Biomedical subjects

Ping Wang

Publications and source records attributed to Ping Wang.

At least 163 records · Page 9Linked to original sources

PubMed2005

Saturated free fatty acid, palmitic acid, induces apoptosis in fetal hepatocytes in culture.

To investigate the effects of saturated free fatty acid, palmitic acid (PA), on hepatocytes, we administered PA to rat hepatocytes. We demonstrated that PA inhibited the cell growth as a dose- and time-dependent manner in rat hepatocytes. PA-induced morphological changes including swelling, membrane dissolution and formation of debris, and apoptosis with appearance of sub-G1 fraction determined by cell cycle analysis after treatment for 4 days. The level of Bcl-2 was slightly decreased, in contrast, the level of Bax elevated markedly, which resulted in a significant decrease of Bcl-2/Bax ratio after PA treatment on HepG2 cells. These findings demonstrated that PA induces cell death on hepatocytes, perhaps via mitochondria-mediated apoptosis. Furthermore, the present study indicates that PA's cell toxicity may play important roles in the transition from steatosis to steatohepatitis in human especially with obesity.

Animals↗

PubMed2005

Idiopathic intracranial hypertension, polycystic-ovary syndrome, and thrombophilia.

We studied thrombophilia, hypofibrinolysis, and polycystic-ovary syndrome (PCOS) in 65 women consecutively referred because of idiopathic intracranial hypertension (IIH) as a means of better understanding the origin of IIH, with the ultimate goal of developing novel medical therapies for IIH. Our hypothesis: IIH results in part from inadequate drainage of cerebrospinal fluid (CSF) resulting from thrombotic obstruction to CSF resorption-outflow, favored by thrombophilia-hypofibrinolysis. We conducted the polymerase chain reaction (PCR) and assessed serologic coagulation measures in 65 women (64 of them white) with IIH, PCR in 102 healthy white female controls (72 children, 30 age-matched adults), and serologic measures in the 30 adults. Of the 65 patients, 37 (57%) were found to have PCOS; 16 (43%) were obese (BMI > or = 30 to < 40), and 19 (51%) were extremely obese (BMI > or = 40). Of the 65 women with IIH, 25 (38%) were homozygous for the thrombophilic C677T MTHFR mutation, compared with 14% of controls (14/102) ( P = .0002). Thrombophilic high concentrations of factor VIII (>150%) were present in 9 of 65 (14%) IIH cases, compared with 0 of 30 controls (0%) (Fisher's p [p f ] = .053). An increased concentration of lipoprotein A (> or = 35 mg/dL), associated with hypofibrinolysis, was present in 19 of 65 IIH cases (29%), compared with 3 of 30 controls (10%) (p f = .039). IIH occurred in 18 of 65 IIH patients taking estrogen-progestin contraceptives (28%), in 6 patients taking hormone-replacement therapy (9%), and in 5 pregnant subjects (8%). We speculate that PCOS, associated with obesity and extreme obesity, is a treatable promoter of IIH. We also speculate that if thrombophilia-hypofibrinolysis and subsequent thrombosis are associated with reduced CSF resorption in the arachnoid villi of the brain, thrombophilia and hypofibrinolysis-often exacerbated by thrombophilic exogenous estrogens, pregnancy, or the paradoxical hyperestrogenemia of PCOS-are treatable promoters of IIH.

Adolescent↗

PubMed2005

Metformin-diet benefits in women with polycystic ovary syndrome in the bottom and top quintiles for insulin resistance.

We prospectively assessed whether metabolic and menstrual benefits of metformin-diet were equally realized in women with polycystic ovary syndrome (PCOS), categorized by pretreatment top (n = 32) and bottom (n = 35) quintile homeostasis model assessment insulin resistance (IR). Effects of metformin (2.55 g/d) and diet (6300-8400 J/d [1500-2000 cal/d], 26% protein, 44% carbohydrate) were prospectively assessed for 12 months. Pretreatment, the bottom and top insulin-resistant quintile groups differed by median weight (84 vs 121 kg), insulin (7.8 vs 40.5 I(1/4) U/mL), IR (1.62 vs 9.28), homeostasis model assessment insulin secretion (131 vs 416), glucose (82 vs 98 mg/dL), sex hormone-binding globulin (40 vs 15 nmol/L), (all P < .0001), free androgen index (2.76 vs 10.8) ( P < .001), triglyceride (92 vs 131 mg/dL), high-density lipoprotein (46 vs 39 mg/dL), systolic blood pressure (116 vs 128 mm Hg), and diastolic blood pressure (76 vs 84 mm Hg), (all P < .01). After 12 months on metformin-diet, weight fell by 7% in both insulin-resistant groups (P < .0001), insulin, IR, and insulin secretion fell in the top insulin-resistant group by 60%, 64%, and 39% (all P < .0001), with smaller reductions in the bottom insulin-resistant group of 18%, 13% (P > .05 for both), and 22% (P < .01), respectively. The free androgen index fell 39% (P > .01) in the top insulin-resistant group. The pretreatment percentage of expected menses in the top insulin-resistant quintile (26 +/- 39%) was 1.6 times less than in the bottom insulin-resistant quintile (41 +/- 38%) (P = .026). Over the 12-month treatment period, the percentage of spontaneous regular normal menses increased to 72 +/- 27% in the top insulin-resistant quintile group (P < .0001) and to 77 +/- 31% in the bottom quintile group (P < .0001), with no group difference (P = .33). Metformin-diet metabolic effects were much more marked in women in the top vs the bottom quintile for IR. Women with PCOS in the bottom insulin-resistant quintile, conventionally thought not to respond optimally to metformin-diet, nevertheless experience significant metabolic and menstrual benefits. Metformin-diet should benefit most women with PCOS, even those with normal serum insulin, without IR.

Blood Pressure↗

PubMed2005

The factor V Leiden mutation, high factor VIII, and high plasminogen activator inhibitor activity: etiologies for sporadic miscarriage.

We hypothesized that the thrombophilic G1691A factor V Leiden gene mutation was a common significant cause of sporadic first trimester miscarriage. We compared thrombophilia and hypofibrinolysis in 92 women (85 white, 5 black, 2 other) with 1 or more pregnancies and 1 miscarriage (143 live births, 92 miscarriages) (cases) and in 380 female controls (355 white, 21 black, 4 other) with 1 or more pregnancies and 0 miscarriages (964 live births). We used polymerase chain reaction techniques to characterize thrombophilic gene mutations (G1691A V Leiden [FV], G20210A prothrombin, C677T/A1298C MTHFR) and hypofibrinolytic gene mutations (plasminogen activator inhibitor [PAI-1] activity 4G4G). We carried out serologic measures of thrombophilia (homocysteine, anticardiolipin antibodies [ACLA] immunoglobulin G and immunoglobulin M, lupus anticoagulant, factor VIII, factor XI, protein C, total and free protein S, antithrombin III) and hypofibrinolysis (plasminogen activator inhibitor activity [PAI-Fx], lipoprotein[a]). Of the 380 controls, 6 (1.6%) had FV heterozygosity vs 12 heterozygous and 2 homozygous FV cases (15.2% [14/92]; P < .0001). Plasminogen activator inhibitor activity was high (> or =21.1 U/mL) in 21 (33%) of 63 cases vs 27 (18%) of 152 controls (P = .013). Factor VIII was high (>150%) in 15 (31%) of 48 cases vs 19 (18%) of 103 controls (P = .079). By logistic regression, with age and factor VIII (categorical [< or =150%, >150%]) as explanatory variables and group (cases, controls) as the dependent variable, after adjusting for age, high factor VIII was a significant predictor for miscarriage (odds ratio, 3.28; 95% confidence interval, 1.34-8.04; P = .01). There were no other group differences (P > .05) in measures of thrombophilia and hypofibrinolysis. After unexplained sporadic first trimester miscarriage, we suggest that measurements be done of the FV mutation, PAI-Fx, and factor VIII, etiologies for sporadic miscarriage.

Abortion, Spontaneous↗

PubMed2005

Congenital iodine deficiency and hypothyroidism impair LTP and decrease C-fos and C-jun expression in rat hippocampus.

Iodine is essential for the synthesis of triiodothyronine (T(3)) and thyroxine (T(4)). Iodine deficiency leads to inadequate thyroid hormone. Thyroid hormones deficiency during brain development affects cognitive functions, such as attention, learning, and memory. However, the mechanism underlying these deficits is unclear. To investigate the role of iodine deficiency and hypothyroidism in synaptic plasticity, this study examined the induction of long-term synaptic plasticity (LTP) and expression of immediate early (IEA) gene proteins in rat hippocampus following congenital iodine deficiency or hypothyroidism. Through gestation and lactation, iodine-deficient or hypothyroid dam rats were administered with either iodine-deficient diet or methimazole-added drinking water. Exposure was terminated on postnatal day (PN) 30. In hippocampus of pup rats, the induction of LTP in area CA1 was determined on PN60 and the expression of c-fos and c-jun proteins was examined on PN20, PN30 and PN60. Compared to control pups, both treated groups have shown: (1) significantly lower concentrations of serum FT(3) and FT(4), (2) much smaller population spike (PS) amplitude (p<0.01) and field-excitatory postsynaptic potential (f-EPSP) slope induced by high-frequency stimulation (HFS) (P<0.01), and (3) significantly lower integrated optical density (IOD) total of c-fos and c-jun expression (P<0.05 or P<0.01). In summary, iodine deficiency and hypothyroidism during critical periods of brain development impair LTP induction and decrease the expression of c-fos and c-jun proteins in hippocampus.

Aging↗

PubMed2005

A novel approach to maintaining cardiovascular stability after hemorrhagic shock: beneficial effects of adrenomedullin and its binding protein.

BACKGROUND: Vascular responsiveness to adrenomedullin (AM), a recently discovered vasodilator peptide, is depressed after hemorrhage and resuscitation. Downregulation of AM binding protein-1 (ie, AMBP-1) appears to be responsible for this hyporesponsiveness. Therefore, we hypothesize that administration of AM/AMBP-1 improves cardiovascular responses after hemorrhagic shock and resuscitation. METHODS: Male rats were bled to and maintained at a mean blood pressure of 40 mm Hg for 90 minutes. The animals were then resuscitated with 4 times the volume of shed blood with Ringer's lactate over 60 minutes. At 15 minutes after the beginning of resuscitation in hemorrhaged animals, AM alone, AMBP-1 alone, AM in combination with AMBP-1, or vehicle (phosphate-buffered saline solution) was administered intravenously over 45 minutes. At 4-hour postresuscitation, in vivo left ventricular contractility parameters, maximal rates of ventricular pressure increase (+dP/dt max ) and decrease (-dP/dt max ), were determined. Cardiac output and organ blood flow were measured with the use of radioactive microspheres. In an additional group of animals, cardiac tumor necrosis factor-alpha (TNF-alpha) levels were measured by an enzyme-linked immunosorbent assay. RESULTS: Four hours after resuscitation, +dP/dt max , -dP/dt max , cardiac output, and organ blood flow in the liver, small intestine, and kidneys were decreased while treatment with AM/AMBP-1 increased these parameters ( P < .05). Moreover, cardiac TNF-alpha levels were elevated at 4 hours after hemorrhage and resuscitation, while AM/AMBP-1 treatment reduced them to sham levels ( P < .05). CONCLUSIONS: Administration of AM/AMBP-1 appears to be a useful approach for restoring and maintaining cardiovascular stability after severe hemorrhagic shock and crystalloid resuscitation.

Adrenomedullin↗

PubMed2005

Study of correlation between expression of bradykinin B2 receptor and pathological grade in human gliomas.

In clinical practice there is a difference in response of the blood-tumour barrier (BTB) permeability induced by bradykinin in brain tumours with the same pathology. The variability in response of tumours to bradykinin is likely to be related to the expression level of bradykinin B(2) receptor. This study used fresh human glioma samples to determine the expression level of bradykinin B(2) receptor on gliomas with different pathological grades. The grade of tumour was classified using the WHO classification. To determine the bradykinin B(2) receptor expression level in gliomas, Immunohistochemistry and Western blot methods were used. In 24 cases of gliomas there were eight cases of WHO I glioma, eight cases of WHO II glioma and eight cases of WHO III glioma. Both Western blot and immunohistochemistry showed bradykinin B(2) receptors localized on tumour cells, whilst brain cells at the edge of the glioma hardly expressed B(2) receptor. There were significant differences of bradykinin B(2) receptor expression level among different pathological grades of glioma. The expression of B(2) receptor in the three grades of glioma was in the order of WHO I < WHO II < WHO III. Determination of bradykinin B(2) receptor expression level in human glioma may be useful in screening glioma patients to predict whether they will be suitable for opening of the blood - tumour barrier with bradykinin or its analogue.

Adolescent↗

PubMed2005

Enoxaparin prevents progression of stages I and II osteonecrosis of the hip.

UNLABELLED: In a prospective pilot study, we hypothesized that enoxaparin (60 mg/day for 12 weeks) would prevent progression of Stages I and II osteonecrosis of the hip associated with thrombophilia or hypofibrinolysis or both over > or = 108 weeks of followup versus untreated historic controls, with different treatment responses in primary versus corticosteroid-associated secondary osteonecrosis. Patients with one or more thrombophilic-hypofibrinolytic disorder and Ficat Stages I or II osteonecrosis of at least one hip were included. A blinded committee interpreted anteroposterior and frog-leg lateral radiographs at entry in the study and every 36 weeks to > or = 108 weeks. Maintenance of the disease at Stages I and II versus progression of the osteonecrosis to Stages III and IV requiring total hip replacement was the major end point. Sixteen patients had primary osteonecrosis (25 hips; 13 Stage I, 12 Stage II), and 12 had secondary osteonecrosis (15 hips; five Stage I, 10 Stage II). With no Enoxaparin-related complications, 19 of 20 hips (95%) with primary osteonecrosis were unchanged from Stages I and II osteonecrosis at > or = 108 weeks; 12 of 15 hips (80%) with secondary osteonecrosis progressed to Stages III and IV osteonecrosis. In primary osteonecrosis at > or = 108 weeks, survival of 95% hips, or 76% (19/25 hips, based on intent to treat), compared favorably with untreated historical controls (approximately 20% 2-year survival), comparable to 20% survival in secondary hip osteonecrosis. Enoxaparin may prevent progression of primary hip osteonecrosis, decreasing the incidence of total hip replacement. LEVEL OF EVIDENCE: Therapeutic study, II-1 (prospective cohort study).

Arthroplasty, Replacement, Hip↗

PubMed2005

The John Charnley Award: heritable thrombophilia and development of thromboembolic disease after total hip arthroplasty.

UNLABELLED: We retrospectively assessed whether heritable thrombophilia-hypofibrinolysis was more common in patients developing venous thromboembolism after total hip replacement than among control patients who did not develop venous thromboembolism, as an approach to better identify causes of venous thromboembolism after total hip arthroplasty. Twenty patients with proximal deep venous thrombosis after THA and 23 patients with symptomatic pulmonary embolism were compared with 43 control patients who did not have postoperative venous thromboembolism. Five of 42 patients with venous thromboembolism (12%) and 0 of 43 control patients (0%) had antithrombin III deficiency (< 75%). Nine of 42 patients with venous thromboembolism (21%) and 2 of 43 control patients (4.7%) had protein C deficiency (< 70%). Ten of 43 patients with venous thromboembolism (9 heterozygous, 1 homozygous; 23%) and 1 of 43 control patients (heterozygous; 2%) had the prothrombin gene mutation. Patients who had venous thromboembolism after total hip arthroplasty were more likely than matched control patients to have heritable thrombophilia with antithrombin III or protein C deficiency, or homo-heterozygosity for the prothrombin gene mutation. Screening for these three tests of heritable thrombophilia before total hip arthroplasty should improve the identification of patients with a reduced risk of venous thromboembolism who may need only mild thromboprophylaxis, and of those patients with heritable thrombophilia in whom prophylaxis should be more aggressive. LEVEL OF EVIDENCE: Prognostic study, Level II-1 (lesser-quality RCT). See the Guidelines for Authors for a complete description of levels of evidence.

Adult↗

PubMed2005

Adrenomedullin and its binding protein attenuate the proinflammatory response after hemorrhage.

OBJECTIVE: The neuroendocrine response to hemorrhage is to maintain perfusion to the heart and brain, often at the expense of other organ systems. Systemic inflammation and tissue injury are important components of pathophysiologic consequences of hemorrhage. We have recently shown that administration of adrenomedullin (AM, a potent vasodilator peptide) and adrenomedullin binding protein-1 (AMBP-1) prevented the transition from the hyperdynamic to the hypodynamic stage in the progression of sepsis. However, the effect of AM/AMBP-1 on the inflammatory response after hemorrhage remains unknown. We therefore hypothesized that administration of AM/AMBP-1 during fluid resuscitation in hemorrhaged animals (i.e., posttreatment) attenuates tissue injury and the proinflammatory response. DESIGN: Prospective, controlled, and randomized animal study. SETTING: A research institute laboratory. SUBJECTS: Male adult rats. INTERVENTIONS: Rats were bled, and then a mean arterial pressure was maintained at 40 mm Hg for 90 mins. They were then resuscitated by infusion of four times the volume of shed blood using Ringer's lactate solution for 60 mins. MEASUREMENTS AND MAIN RESULTS: Fifteen minutes after the beginning of resuscitation, AM (12 microg/kg of body weight) in combination with AMBP-1 (40 microg/kg of body weight) was administered via a femoral venous catheter for 45 mins. Blood samples were collected 4 hrs postresuscitation and assayed for levels of liver enzymes (i.e., alanine aminotransferase and aspartate aminotransferase), lactate, creatinine, proinflammatory cytokines tumor necrosis factor and high mobility group box 1, and anti-inflammatory cytokine interleukin-10. The results indicate that levels of alanine aminotransferase, aspartate aminotransferase, creatinine, lactate, tumor necrosis factor, and high mobility group box 1 markedly elevated after hemorrhage and resuscitation, and AM/AMBP-1 treatment significantly attenuated these increases. In contrast, the serum concentration of anti-inflammatory cytokine interleukin-10 was increased by the treatment of AM/AMBP-1. Moreover, AM/AMBP-1 treatment significantly improved the survival rate from 35% in vehicle-treated animals to 73% in AM/AMBP-1-treated animals in a low-volume resuscitation model of hemorrhage. CONCLUSION: The combined administration of AM and AMBP-1 effectively suppresses hemorrhage-elicited organ injury and reduces hemorrhage-induced mortality, partly through down-regulation of proinflammatory cytokines (tumor necrosis factor and high mobility group box 1) and up-regulation of the anti-inflammatory cytokine interleukin-10.

Adrenomedullin↗

PubMed2005

Proapoptotic effect of curcumin on human neutrophils: activation of the p38 mitogen-activated protein kinase pathway.

OBJECTIVE: Despite advances in the management of sepsis and acute respiratory distress syndrome, the mortality rate remains high. Delayed apoptosis of neutrophils is associated with multiple organ failure under those conditions. Thus, development of nontoxic neutrophil apoptosis regulating molecules may provide a novel therapeutic strategy. Curcumin is a promising dietary supplement for cancer prevention. However, the effect of curcumin on human neutrophil apoptosis remains unknown. We therefore hypothesized that curcumin would produce a proapoptotic effect on neutrophils. DESIGN: Prospective, controlled, and randomized in vitro study. SETTING: Research institute laboratory. SUBJECTS: Human peripheral neutrophils obtained from normal subjects. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: In the presence or absence of curcumin, both spontaneous neutrophil apoptosis and apoptosis of neutrophils following transmigration across a human lung endothelium-epithelium bilayer were studied by morphology and terminal dUTP nucleotide end labeling analyses, respectively. Myeloperoxidase activity and migration assays were performed to determine the impact of curcumin on neutrophil function. To elucidate the potential mechanism, the p38 mitogen-activated protein kinase pathway and caspase-3 activity were examined by Western blotting and enzymatic analyses. The data demonstrate that curcumin increased constitutive neutrophil apoptosis and abrogated the transbilayer migration-induced delay in neutrophil apoptosis. Neutrophil activation was reduced by curcumin treatment as evidenced by a decrease in migration and myeloperoxidase release. A marked increase in p38 phosphorylation and caspase-3 activity was observed following curcumin exposure. In addition, inhibition of p38 mitogen-activated protein kinase with SB203580 suppressed apoptosis and caspase-3 activation induced by curcumin. Thus, activation of p38 mitogen-activated protein kinase or an increase in caspase-3 activity appears to contribute to the proapoptotic effect of human neutrophil apoptosis by curcumin. CONCLUSION: The characteristics of curcumin, including its proapoptotic effect and antidegranulation effect, make it a potential candidate for the therapy of neutrophil-induced lung injury and sepsis.

Antineoplastic Agents↗

PubMed2005

Macrophage migration inhibitory factor within the alveolar spaces induces changes in the heart during late experimental sepsis.

Respiratory dysfunction during sepsis is common. However, although lung function can often be adequately supported, death frequently results from cardiovascular collapse. Despite intense investigation, the mechanism underlying the myocardial dysfunction of sepsis remains unclear. Macrophage migration inhibitory factor (MIF), an important cytokine released in sepsis and the acute respiratory distress syndrome, is a known cardiac depressant. We hypothesized that MIF released from the lung results in myocardial dysfunction during sepsis. In murine models of polymicrobial sepsis, we demonstrate a significant increase in the lungs of total and lavagable MIF between 20 and 30 h post induction of sepsis. At 30 h post sepsis, the lungs released MIF into the pulmonary circulation, increasing the plasma concentration by up to 51% in a single pass. Exogenous MIF, instilled into the lungs, increased alveolar keratinocyte-derived chemokine (KC), Macrophage inflammatory protein-2 (MIP2), and tumor necrosis factor alpha (TNFalpha) at 3 h, and plasma KC and MIP2 at 6 h postinstillation. This was associated with an increase in p38 mitogen-activated protein kinase and c-Jun N-terminal kinase phosphorylation. Because changes in mitogen-activated protein kinase activation can lead to myocardial depression, these data suggest that MIF released from the lungs may be responsible, at least in part, for the cardiac dysfunction seen in the late stages of sepsis.

Animals↗

PubMed2005

Mechanisms responsible for vascular hyporesponsiveness to adrenomedullin after hemorrhage: the central role of adrenomedullin binding protein-1.

OBJECTIVE: Irreversible hypovolemia remains a major clinical problem. Preliminary studies indicate that administration of adrenomedullin and adrenomedullin binding protein-1 in combination (AM/AMBP-1) after hemorrhage, improves cardiovascular function despite the increased levels of AM. Our aim was to determine whether vascular responsiveness to AM is reduced after hemorrhage and, if so, to elucidate the possible mechanism responsible for such hyporesponsiveness. METHODS: Male rats were bled to and maintained at a mean arterial pressure of 40 mm Hg for 90 minutes. The animals were then resuscitated with 4 times the volume of shed blood with lactated Ringer's solution over 60 minutes. At 1.5 hours postresuscitation, vascular responses to AM and AMBP-1, plasma levels of AM and AMBP-1, AMBP-1 and AM receptor gene expression were measured. In additional animals, AM and AMBP-1 were administered intravenously at 15 minutes after resuscitation over 45 minutes. Serum levels of liver enzymes, lactate, creatinine, TNF-alpha, IL-6, and IL-10 were measured at 1.5 hours postresuscitation. RESULTS: AM-induced vascular relaxation decreased significantly after hemorrhage and resuscitation, which was markedly improved by AMBP-1. However, AM receptor gene expression did not change under such conditions. Hemorrhage-induced AM hyporesponsiveness was accompanied by the decreased expression and release of AMBP-1. Moreover, AM/AMBP-1 treatment down-regulated TNF-alpha and IL-6, up-regulated IL-10, and attenuated organ injury. CONCLUSIONS: The decreased AMBP-1 levels rather than alterations in AM receptors are responsible for producing AM hyporesponsiveness after hemorrhage. Thus, administration of AMBP-1 in combination with AM can be useful to reduce organ injury after severe hypovolemia.

Adrenomedullin↗

PubMed2005

Accurate setup of paraspinal patients using a noninvasive patient immobilization cradle and portal imaging.

Because of the proximity of the spinal cord, effective radiotherapy of paraspinal tumors to high doses requires highly conformal dose distributions, accurate patient setup, setup verification, and patient immobilization. An immobilization cradle has been designed to facilitate the rapid setup and radiation treatment of patients with paraspinal disease. For all treatments, patients were set up to within 2.5 mm of the design using an amorphous silicon portal imager. Setup reproducibility of the target using the cradle and associated clinical procedures was assessed by measuring the setup error prior to any correction. From 350 anterior/posterior images, and 303 lateral images, the standard deviations, as determined by the imaging procedure, were 1.3 m, 1.6 m, and 2.1 in the ant/post, right/left, and superior/inferior directions. Immobilization was assessed by measuring patient shifts between localization images taken before and after treatment. From 67 ant/post image pairs and 49 lateral image pairs, the standard deviations were found to be less than 1 mm in all directions. Careful patient positioning and immobilization has enabled us to develop a successful clinical program of high dose, conformal radiotherapy of paraspinal disease using a conventional Linac equipped with dynamic multileaf collimation and an amorphous silicon portal imager.

Equipment Design↗

PubMed2005

Synaptotagmin VII is targeted to secretory organelles in PC12 cells, where it functions as a high-affinity calcium sensor.

Synaptotagmin (syt) I is thought to act as a Ca2+ sensor that regulates neuronal exocytosis. Fifteen additional isoforms of syt have been identified, but their functions are less well understood. Here, we used PC12 cells to test the idea that different isoforms of syt impart cells with distinct metal (i.e., Ca2+, Ba2+, and Sr2+) requirements for secretion. These cells express syt's I and IX (syt IX sometimes referred to as syt V), which have low apparent metal affinities, at much higher levels than syt VII, which we show has a relatively high apparent affinity for metals. We found that syt I and VII partially colocalize on large dense core vesicles and that upregulation of syt VII produces a concomitant increase in the divalent cation sensitivity of catecholamine release from PC12 cells. Furthermore, RNA interference-mediated knockdown of endogenous syt VII reduced the metal sensitivity of release. These data support the hypothesis that the complement of syt's expressed by a cell, in conjunction with their metal affinity, determines the divalent cation sensitivity of exocytosis.

Animals↗

PubMed2005

Amaurosis fugax: associations with heritable thrombophilia.

The aim of this study was to prospectively assess associations between amaurosis fugax, inherited thrombophilia, and acquired thrombophilia. Thrombophilia and hypofibrinolysis were studied in 11 cases (eight women, three men; all white) with amaurosis fugax, 57 +/- 17 years old, selected by the absence of abnormal brain magnetic resonance imaging (MRI), magnetic resonance angiography (MRA), magnetic resonance venography (MRV), ipsilateral internal carotid artery plaque, atrial fibrillation, or cardiac thrombus. Cases were compared to 78 healthy adult white controls (53 +/- 18 years old) for serologic measures, and by polymerase chain reaction to 248 healthy white controls (78 adults, 170 children) for gene mutations. All 11 cases had one or more familial thrombophilic coagulation disorder including one heterozygous for the G1691A factor V Leiden mutation, two with low free protein S, four with high factor VIII, three with resistance to activated protein C, three homozygous for the C677T methylenetetrahydrofolate reductase (MTHFR) mutation, two compound C677T-A1298C MTHFR heterozygotes, and three with hypofibrinolytic 4G4G homozygosity for the PAI-1 gene. The case with factor VIII of 160% had two other thrombophilias (compound MTHFR C677T-A1298C heterozygosity, resistance to activated protein C), and hypofibrinolytic high Lp(a). Thrombophilic C677T MTHFR homozygosity or compound C677T-A1298C heterozygosity was present in five of 10 (50%) cases vs. 30 of 248 (12%) controls, Fisher's p (p(f)) = .005. Thrombophilic factor VIII was high in four of 10 (40%) cases vs. 0 of 38 controls, p(f) = .001. Thrombophilic hyperestrogenemia in five of the eight women (four exogenous estrogen, one pregnant) may have interacted with inherited thrombophilia-hypofibrinolysis, promoting thrombus formation. In cases selected by the absence of abnormal brain magnetic resonance imaging, significant ipsilateral internal carotid artery plaque, atrial fibrillation, or cardiac thrombus, we speculate that amaurosis fugax can be caused by reversible (by anticoagulation) retinal artery thrombi associated with heritable thrombophilia and/or hypofibrinolysis, often augmented by estrogen-driven acquired thrombophilia.

Adult↗

PubMed2005

Associations of thrombophilia, hypofibrinolysis, and retinal vein occlusion.

We prospectively assessed whether thrombophilia and hypofibrinolysis, amplified by thrombophilic hormone replacement therapy (HRT), were associated with retinal vein occlusion (RVO). We studied 44 cases (18 men, 26 women), > or = 3 months after RVO, 42 with central RVO, 2 with branch RVO, in the consecutive order of their referral by 2 community-based ophthalmologists. PCR and serologic coagulation assays were compared to 83 and 40 healthy adult normal controls, respectively. The 4G allele frequency of the plasminogen activator inhibitor-1 (PAI-1) gene, associated with hypofibrinolysis, was 56 of 88 (64%) in cases vs 79 of 166 (48%) in controls, X(2) = 5.95, p = .015. The PAI-1 gene product, plasminogen activator inhibitor activity (PAI-Fx), was higher in cases than controls (age-race-sex- adjusted mean 12.2 U/mL vs 6.3, p = .013). By stepwise logistic regression, the PAI-1 gene 4G allele was associated with RVO, odds ratio 1.94, 95% CI 1.12-3.34, p = .018. Thrombophilic resistance to activated protein C (RAPC) was present in 6 of 32 (19%) of cases vs 0 of 40 (0%) controls, Fisher's p [p(f)] = .006. Thrombophilic high factor VIII (> 150%) was present in 3 of 30 (10%) cases vs 0 of 40 (0%) controls, p = .041, p(f) = .07. Comparing 23 RVO cases < or = age 55 and controls < or = age 55 (n = 44 for PCR, n = 40 for serologic measures), RAPC was present in 17% of cases vs 0% controls (p(f) = .026), high Factor VIII in 17% vs 0% (p(f) = .026), heterozygosity for the G1691A Factor V Leiden mutation in 13% vs 2% (p(f) = 0.11), and the 4G allele frequency of the PAI-1 gene 74% vs 39% (p = .0001). PAI-Fx was higher in cases than controls (age-race-sex adjusted mean 12.7 U/mL vs 6.7, p = .016). The case-control odds ratio for the PAI-1 4G allele was 5.54, 95% CI = 1.86-16.7, p = .002. Of the 26 women, 9 (35%) took HRT; 4 of the 9 had PAI-1 gene 4G4G homozygosity, 2 had thrombophilic high anticardiolipin antibody (IgG), 1 was heterozygous for the G1691A Factor V Leiden mutation, and 2 were heterozygous for the thrombophilic PL A1/A2 mutation of the platelet glycoprotein IIb/IIIa gene. Associations between heritable coagulation disorders and RVO, most marked in cases < or = age 55, and often amplified in women by thrombophilic HRT, are, speculatively, causal.

Adult↗

PubMed2005

Idiopathic intracranial hypertension: associations with thrombophilia and hypofibrinolysis in men.

The existence of an association between idiopathic intracranial hypertension (IIH) and coagulation disorders in men was assessed prospectively. Microthrombi, associated with thrombophilia-hypofibrinolysis, occlude arachnoid sinus villi, thus reducing resorption of cerebrospinal fluid, leading to IIH. Ten consecutively referred men with IIH, nine whites, one African American, median age 36 years, were 2 to 1 matched by age and race by healthy male controls. Polymerase chain reaction assays were done for four thrombophilic and one hypofibrinolytic gene mutations: G1691A factor V Leiden, G20210A prothrombin, C677T MTHFR, platelet glycoprotein IIb/IIIa (PL A1/A2), and 4G/5G polymorphism of the plasminogen activator inhibitor (PAI-1) gene promoter. Coagulation measures in plasma included dilute Russel's viper venom time (dRVVT), activated partial thromboplastin time (aPTT), the lupus anticoagulant, factor VIII, factor XI, plasminogen activator inhibitor activity (PAI-Fx), protein C antigenic, protein S total (antigenic), protein S free (antigenic), antithrombin III (functional), and resistance to activated protein C (RAPC). Tests performed on serum included anticardiolipin antibodies, homocysteine, and Lp(a). The body mass index was 40 kg/m(2) or greater (extremely obese) in two men, 30 to 40 kg/m(2) (obese) in three, and was 25 to 30 kg/m(2) in five (overweight). Cases differed from controls for inherited 4G4G homozygosity of the PAI-1 gene, four of 10 (40%) vs. one of 20 (5%), Fisher's p [p(f)]= .031, and for high levels (>21.1 U/mL) of the hypofibrinolytic PAI-1 gene product, PAI-Fx, 5 of 10 (50%) vs. one of 18 (6%), p(f) = .013. Thrombophilic factor VIII was high (> or = 150%) in three of 10 (30%) cases vs. zero of 16 (0%) controls, p(f)=. 046. The thrombophilic lupus anticoagulant was present in two of 10 (20%) cases vs. zero of 32 (0%) controls, p(f) = .052. Heritable hypofibrinolysis and heritable and acquired thrombophilia appear, speculatively, to be treatable etiologies of IIH in men. Understanding contributions of hypofibrinolysis and thrombophilia to the development of IIH should facilitate development of novel new approaches to treat this often-disabling neurologic disorder.

Adolescent↗