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Biomedical subjects

T Tracy

Publications and source records attributed to T Tracy.

At least 19 recordsLinked to original sources

Metformin to restore normal menses in oligo-amenorrheic teenage girls with polycystic ovary syndrome (PCOS).

PURPOSE: To describe our clinical experience in using Metformin combined with a high protein-low carbohydrate diet to restore normal menstrual cycles in teenaged females with polycystic ovary syndrome (PCOS). METHODS: To enter the study, patients had to have well-documented PCOS, be oligo- (six cycles or less in the preceding year) or amenorrheic (absence of menstrual cycles for 1 year), and not have exclusionary diseases or drugs. Accompanying a high protein-low carbohydrate diet, Metformin (1.5-2.55 g/day) was given for 10.5 +/- 6.4 months (range, 4.5-26.5 months). Follow-up every 8-10 weeks for > or =6 months was scheduled with interval history, review of menstrual status, assessment of any Metformin-related side effects, brief physical examination, and determination of weight and blood pressure. RESULTS: All 11 girls had normal fasting blood glucose and glycohemoglobin. Pre-Metformin, five girls were amenorrheic, three had only one menstrual cycle in the previous year, and three had > or =6 cycles/year. With Metformin, 10 of 11 girls (91%) resumed regular normal menses; 39% of 38 follow-up visits with regular normal menstrual cycles were ovulatory with normal luteal-phase serum progesterone (> or =2.3 ng/mL). Of the 11 girls, nine (82%) lost weight; five girls lost > or =11 lb and seven lost > or =5 lb. After adjusting for weight reduction, with Metformin, estradiol and progesterone rose (p =.0014,.027, respectively) (changes consistent with resumption of regular normal menses), total plasma cholesterol fell (p =.026), and there was a downward trend in testosterone (p =.068). CONCLUSION: Metformin safely ameliorates the endocrinopathy of PCOS in previously oligo-amenorrheic teenage females with PCOS, facilitating resumption of normal menses in most girls.

Adolescent↗

Parenteral nutrition-associated cholestasis.

Cholestasis is a major complication that occurs frequently in patients with the short bowel syndrome and accounts for the majority of morbidity and mortality in this group of patients. The exact cause of this condition is not known and the etiology is likely multifactorial. Many new mechanistic insights into this disease are discussed and have paved the way for future investigation. For now, prompt recognition, early initiation of enteral feeding, prevention of overfeeding with parenteral nutrition, and agents that induce bile flow may be useful to prevent this catastrophic morbidity.

Animals↗

Hypofibrinolysis, thrombophilia, osteonecrosis.

In the context of additional characterization of the pathoetiologic associations of heritable hypofibrinolysis and thrombophilia with osteonecrosis of the hip, the authors assessed 15 women and 21 men at entry to a 12-week treatment study of the amelioration of Ficat Stages I or II osteonecrosis by low molecular weight heparin (Enoxaparin). All 36 patients had osteonecrosis of the hip; four patients had unifocal osteonecrosis, 25 patients had two joints affected, five had three affected joints, and two had four affected joints. In 11 of 15 women (73%), hyperestrogenemia of pregnancy (20%) or exogenous estrogen supplementation (53%) were associated with the development of osteonecrosis. Five gene mutations affecting coagulation and nine serologic coagulation tests were studied. Compared with control subjects, patients were more likely to have heterozygosity and homozygosity for the hypofibrinolytic 4G polymorphism of the plasminogen activator inhibitor-1 gene. Moreover, the plasminogen activator inhibitor-1 gene product, plasminogen activator inhibitor activity, the major determinant of hypofibrinolysis, was 10 times more likely to be high (> 21.1 U/mL) in patients than in control subjects (31% versus 3%), with a median of 15.7 versus 6.3 U/mL. Compared with controls, patients were more likely to have the thrombophilic methylenetetrahydrofolate reductase gene mutation. In addition, the thrombophilic methylenetetrahydrofolate reductase gene product, homocysteine, was four times more likely to be high (> 13.5 umol/L) in patients than in control subjects (20% versus 5%), with a median of 9.1 versus 7 umol/L. Twenty-three percent of patients had low levels (< 65%) of the thrombophilic free protein S versus 3% of control subjects. Patients were more likely than control subjects to have hypofibrinolytic high lipoprotein (a) (> or = 35 mg/dL), 33% versus 13%. Median lipoprotein (a) was higher in patients than in control subjects, 15 versus 5 mg/dL. Heritable hypofibrinolysis and thrombophilia, often augmented in women by hyperestrogenemia, seem to be major pathoetiologies of osteonecrosis. If the association between coagulation disorders and osteonecrosis reflects cause and effect, as postulated, then anticoagulation with Enoxaparin should be a promising therapy for patients with osteonecrosis.

Adult↗

In vitro inhibition of the cytochrome P450 (CYP450) system by the antiplatelet drug ticlopidine: potent effect on CYP2C19 and CYP2D6.

AIMS: To examine the potency of ticlopidine (TCL) as an inhibitor of cytochrome P450s (CYP450s) in vitro using human liver microsomes (HLMs) and recombinant human CYP450s. METHODS: Isoform-specific substrate probes of CYP1A2, 2C19, 2C9, 2D6, 2E1 and 3A4 were incubated in HLMs or recombinant CYPs with or without TCL. Preliminary data were generated to simulate an appropriate range of substrate and inhibitor concentrations to construct Dixon plots. In order to estimate accurately inhibition constants (Ki values) of TCL and determine the type of inhibition, data from experiments with three different HLMs for each isoform were fitted to relevant nonlinear regression enzyme inhibition models by WinNonlin. RESULTS: TCL was a potent, competitive inhibitor of CYP2C19 (Ki = 1.2 +/- 0.5 microM) and of CYP2D6 (Ki = 3.4 +/- 0.3 microM). These Ki values fell within the therapeutic steady-state plasma concentrations of TCL (1-3 microM). TCL was also a moderate inhibitor of CYP1A2 (Ki = 49 +/- 19 microM) and a weak inhibitor of CYP2C9 (Ki > 75 microM), but its effect on the activities of CYP2E1 (Ki = 584 +/- 48 microM) and CYP3A (> 1000 microM) was marginal. CONCLUSIONS: TCL appears to be a broad-spectrum inhibitor of the CYP isoforms, but clinically significant adverse drug interactions are most likely with drugs that are substrates of CYP2C19 or CYP2D6.

Anticonvulsants↗

The 4G/4G polymorphism of the hypofibrinolytic plasminogen activator inhibitor type 1 gene: an independent risk factor for serious pregnancy complications.

The specific aim of the current study of 133 women with at least 1 pregnancy and measures of hypofibrinolytic and thrombophilic gene mutations was to determine retrospectively whether the mutations were associated with adverse pregnancy outcomes including prematurity, miscarriage, stillbirth, intrauterine growth retardation (IUGR), eclampsia, and abruptio placentae. Four gene mutations (factor V Leiden, methylenetetrahydrofolate reductase [MTHFR], prothrombin, and 4G/5G polymorphism of the plasminogen activator inhibitor type 1 [PAI-1] gene) were assessed by polymerase chain reaction (PCR). One hundred twenty-two women were genotyped for all 4 genes and divided into gene mutation (n = 68) and non-gene (n = 54) groups. The gene mutation group included those with at least 1 thrombophilic mutation (heterozygous for factor V Leiden, heterozygous for prothrombin, and homozygous for MTHFR), or hypofibrinolysis with homozygosity for the 4G polymorphism of the PAI-1 gene. The non-gene mutation group included those with no mutation for all 4 genes (wild-type normal) or who were wild-type normal for the prothrombin and factor V Leiden mutations and heterozygous for MTHFR and/or 4G/5G for the PAI-1 gene, neither heterozygosity associated with coagulation abnormalities. The 68 women with gene mutations, versus 54 in the non-gene mutation group, has more prematurity (10% v 4%, chi2 = 5.4, P = .021), more IUGR (3% v 0%, P = .035), and more total complications of pregnancy (37% v 21%, chi2 = 11.6, P = .001). The number of pregnancies (P = .0001) and 4G/4G polymorphism of the PAI-1 gene (P = .029) were positively associated with complications of pregnancy by stepwise logistic regression when the age, number of pregnancies, and all 4 gene mutations were the explanatory variables. Heritable hypofibrinolysis, mediated by 4G/4G homozygosity for the PAI-1 gene, is an independent significant, potentially reversible risk factor for pregnancy complications, probably acting through thrombotic induction of placental insufficiency.

Antibodies, Anticardiolipin↗

Developmental practicum experiences of preservice teachers in deaf education: implications for practicum placement and faculty-student collaborative research.

The study examined the developmental practicum experiences of second-year graduate students in deaf education. Participants in the study consisted of a convenient sample of five practicum students. Triangulated data for the study came from the researcher's observational notes, e-mail correspondence with participants, and participants' journals. Inductive analysis was used to analyze the data. Results of the study evinced developmental experiences that are different from those reported in previous studies. The results of the study have significant implications for (a) practicum placement of graduate students in deaf education in terms of site-based orientation, use of the clinical model of supervision, opportunities for self-reflection, and periodic practicum seminars; and (b) faculty-student collaborative research in terms of planning, ethical issues, students' time needs, and training.

Curriculum↗

Effect of exogenous estrogen on atherothrombotic vascular disease risk related to the presence or absence of the factor V Leiden mutation (resistance to activated protein C).

Estrogen replacement therapy (ERT), which produces acquired resistance to activated protein C when superimposed on heritable resistance to activated protein C (the mutant Factor V Leiden trait), may promote venous and arterial thrombosis. In a cross-sectional study of 423 women referred for hyperlipidemic therapy (93 of whom [22%] were on ERT), our specific aim was to determine whether ERT and heterozygosity for the Factor V Leiden mutation and/or resistance to activated protein C interacted as risk factors for atherothrombosis. Of the 423 women, 168 (40%) had atherothrombosis, 19 (4%) were heterozygous for Factor V Leiden mutation or had resistance to activated protein C <2 (Factor V Leiden mutation+), and 404 were wild-type normal for the Factor V gene and/or had resistance to activated protein C > or =2 (Factor V Leiden mutation-). By stepwise logistic regression, positive explanatory variables for atherothrombosis included hypertension (p = 0.002), age (p = 0.003), relatives with atherothrombosis (p = 0.002), anticardiolipin antibody immunoglobulin-M (p = 0.02), and a Factor V Leiden mutation*ERT interaction term where atherothrombosis events were more likely in 2 subgroups of women (ERT- and Factor V Leiden mutation-) or (ERT+ and Factor V Leiden mutation+) (p = 0.02). High-density lipoprotein cholesterol was inversely associated with atherothrombosis (p = 0.004). In a separate logistic regression model for the 213 women with a polymerase chain reaction measurement of the Factor V gene, ERT was protective (p = 0.008); the Factor V Leiden mutation was positively associated with atherothrombosis (p = 0.05). The atherothrombosis odds ratio risk for ERT (yes vs no) was 0.36 (95% confidence intervals [CI] 0.16 to 0.74, p = 0.007). The atherothrombosis risk odds ratio in women heterozygous for the Factor V Leiden mutation (vs normal) was 2.00 (95% CI 1.02 to 4.22, p = 0.05). ERT may be protective against atherothrombosis when the Factor V Leiden mutation is absent, whereas the Factor V Leiden mutation may increase risk for atherothrombosis, particularly in the presence of ERT. We suggest that the Factor V Leiden mutation be measured in all women on ERT or before beginning ERT to identify those heterozygous for the Factor V Leiden mutation (4%), in whom ERT is relatively or absolutely contraindicated because of increased risk for atherothrombosis and thromboembolism. A second, much larger group of women will also be identified without the factor V Leiden mutation (96%), in whom ERT may reduce the risk for atherothrombosis.

Activated Protein C Resistance↗

Evidence that anticardiolipin antibodies are independent risk factors for atherosclerotic vascular disease.

Thrombophilic anticardiolipin antibodies (ACLAs) are independent risk factors for atherosclerotic vascular disease. We suggest that ACLAs IgG and IgM be routinely measured as ancillary atherothrombotic risk factors in all patients with atherosclerotic vascular disease events, in those at high risk for atherosclerotic vascular disease, and in those in whom thrombosis is a major pathoetiology.

Aged↗

Metformin-induced resumption of normal menses in 39 of 43 (91%) previously amenorrheic women with the polycystic ovary syndrome.

In 43 amenorrheic women with polycystic ovary syndrome (PCOS), 31 (74%) with fasting hyperinsulinemia (> or =20 microU/mL), our aim was to determine whether Metformin (Bristol-Myers Squibb, Princeton, NJ), which reduces hyperinsulinemia, would reverse the endocrinopathy of PCOS, allowing resumption of regular normal menses. A second aim was to assess the effects of weight loss versus other Metformin-induced effects on ovarian function, and to determine if there were different responses to Metformin between those who lost weight and those who did not. A third aim was to assess associations between PCOS, 4G/5G polymorphism in the promoter sequence of the plasminogen activator inhibitor-1 gene (PAI-1 gene), and PAI activity (PAI-Fx). Of the 43 women, 40 (93%) had normal fasting blood glucose and 37 had normal hemoglobin A1C (HgA1C); onlythree (7%) had type 2 diabetes mellitus. Metformin (1.5 to 2.25 g/d) was given for 6.1+/-5.1 months (range, 1.5 to 24), to 16 patients for less than 3 months, to 12 for 3 to 6 months, and to 15 for at least 6 months. On Metformin, 39 of 43 patients (91%) resumed normal menses. The percentage of women resuming normal menses did not differ among treatment duration groups (P<.1) or among dose groups (P>.1). The body mass index (BMI) decreased from 36.4 + 7 Kg/m2 at study entry to 35.1+/-6.7 on Metformin (P=.0008). Of 43 patients, 28 (67%) lost weight (1 to 69 pounds), with nine (21%) losing at least 12 pounds. On Metformin, the median fasting serum insulin decreased from 26 microU/mL to 22 (P=.019), testosterone decreased from 61 ng/dL to 47 (P=.003), and estradiol increased from 41 pg/mL to 71 (P=.0001). Metformin-induced improvements in ovarian function were independent of weight loss (testosterone decrease, P<.002; estradiol increase, P<.0004). The change in response variables on Metformin did not differ (P>.05) between those who lost weight and those who did not, excepting Lp(a), which increased 4 mg/dL in those who lost weight and decreased 9 mg/dL in those who did not (P = .003). The change in response variables on Metformin did not differ among the five quintiles of weight loss, excepting fasting glucose (P<.05), which increased 6 mg/dL in those who lost the least weight on Metformin versus those in the 60th to 80th percentile for weight loss, in whom glucose decreased 33 mg/dL. Although the pretreatment fasting serum insulin was not significantly correlated with testosterone (r=.24, P=.13) or androstenedione (r=.27, P=.09), on Metformin, the change in insulin correlated positively with the change in testosterone (r=.35, P=.047) and with the change in androstenedione (r=.48, P=.01). Patients were more likely than normal controls (83% v 64%, P=.016) to be heterozygous or homozygous for 4G polymorphism of the PAI-1 gene and were also more likely to have high PAI-Fx (> or =22 U/mL, 28% v3%, chi(2)=10.1, P=.001). Metformin reduces the endocrinopathy of PCOS, allowing resumption of normal menses in most (91%) previously amenorrheic women with PCOS.

Adult↗

Contribution of fasting hyperinsulinemia to prediction of atherosclerotic cardiovascular disease status in 293 hyperlipidemic patients.

In a cross-sectional study of 293 nondiabetic patients (169 men and 124 women) referred for the diagnosis and treatment of hyperlipidemia, our specific aim was to determine whether fasting serum insulin independently contributes to the prediction of atherosclerotic cardiovascular disease (ASCVD) status. Of the 169 men and 124 women, 65 (38%) and 44 (35%), respectively, had ASCVD with at least one of the following: unstable angina, myocardial infarction (MI), angioplasty, coronary artery bypass graft (CABG), claudication, transient ischemic attack, or ischemic stroke. In addition, 42% and 38% had fasting hyperinsulinemia (> or =20 microU/mL). Fasting serum insulin of 20 microU/mL or higher was very common in women (59% to 100%) and men (67% to 88%) when hypertension, obesity, top-decile triglyceride (TG), and bottom-decile high-density lipoprotein cholesterol (HDLC) were concurrent in various combinations. ASCVD events (present or absent) were dependent variables in a stepwise logistic regression model with explanatory variables including age, gender, race, hypertension, cigarette smoking, ASCVD in first-degree relatives at age 55 years or less, Quetelet Index, fasting serum insulin, a gender x insulin interaction term, anticardiolipin antibodies (ACLAs) IgG and IgM, total cholesterol to HDLC ratio, TG, lipoprotein(a) [Lp(a)], and homocysteine. The risk odds ratio for ASCVD (109 events and 184 nonevents) for subjects with top-decile insulin (vthe bottom nine deciles) was 3.71, with a 95% confidence interval (CI) of 1.62 to 8.9 (P = .002). For patients with MI and/or CABG and/or angioplasty ([MCA] 63 events and 184 nonevents), the risk odds ratio for top-decile insulin versus the rest was 5.07 (95% CI, 1.83 to 14.8, P = .002). For patients with MCA at age 55 or less, the gender x insulin interaction term was significant (P = .0004); the risk odds ratio for men with top-decile insulin was 13.28 (95% CI, 3.82 to 51.65, P = .0001). Hyperinsulinemia is very common in nondiabetic hyperlipidemic women and men. Fasting serum insulin, a crude, simple, practical, and inexpensive measure, independently and uniformly improved the prediction of ASCVD status beyond traditional risk factors and lipid variables in patients referred for treatment of hyperlipidemia.

Adult↗

Plasminogen activator inhibitor activity: an independent risk factor for the high miscarriage rate during pregnancy in women with polycystic ovary syndrome.

In 41 women with at least one pregnancy drawn from a group of 149 (108 never-pregnant) women with polycystic ovary syndrome (PCOS), our specific aim was to determine whether hypofibrinolysis mediated by high plasminogen activator inhibitor activity (PAI-Fx) is an independent risk factor for miscarriage. The 41 women had 77 total pregnancies with 34 miscarriages (44%) and 42 live births (55%). There were 12 women with at least one pregnancy, at least one miscarriage, and no live births (16 pregnancies and 16 miscarriages). There were 15 women with at least one pregnancy, no miscarriages, and at least one live birth (25 pregnancies and 28 live births). Of 12 women with only miscarriages and no live births, 67% had PAI-Fx greater than 16.4 U/mL (normals' 95th percentile), versus 29% of 15 women with no miscarriages and all live births (chi2 = 3.8, P = .052). By stepwise logistic regression, the number of pregnancies (P = .0001) and PAI-Fx (P = .016) were significant positive explanatory variables for the number of miscarriages. Age, 4G/5G polymorphisms of the PAI gene, factor V Leiden, methylenetetrahydrofolate reductase (MTHFR) gene mutations, androstenedione, testosterone, sex hormone-binding globulin, the Quetelet index, and fasting serum insulin and glucose were not significant variables in the logistic regression model. In a separate stepwise logistic regression, three nonoverlapping groups of women (12 with > or = 1 pregnancy, > or = 1 miscarriage, and 0 live births, 10 with > or = 1 pregnancy, > or = 1 miscarriage, and > or = 1 live births, and 15 with > or = 1 pregnancy, 0 miscarriages, and > or = 1 live births) were the dependent variables. PAI-Fx was positively associated (P = .05) with the group with the worst pregnancy outcome (> or = 1 pregnancy, > or = 1 miscarriage, and 0 live births). The 41 women with PCOS and at least one pregnancy were more likely than healthy normal controls to have heterozygosity and homozygosity for the 4G/5G polymorphism of the PAI-1 gene (P = .028), but did not differ from normals for factor V Leiden (P > .10) or MTHFR (P > .09) mutations. PAI-Fx is a predominant independent significant positive reversible risk factor for miscarriage in women with PCOS.

Abortion, Spontaneous↗

The plasminogen activator inhibitor-1 gene, hypofibrinolysis, and osteonecrosis.

In 59 patients with osteonecrosis of the hip, four genes associated with thrombophilia or hypofibrinolysis along with coagulation tests were studied to determine the pathoetiologic associations of heritable coagulation disorders with osteonecrosis. Patients did not differ from healthy control subjects for the thrombophilic Factor V Leiden, prothrombin, or methylenetetrahydrofolate reductase mutations. The plasminogen activator inhibitor-1 gene was shifted toward homozygosity for the 4G polymorphism; 41% of patients with osteonecrosis were homozygous for the 4G/4G polymorphism versus 20% of 40 healthy control subjects. The gene product of the 4G polymorphism, hypofibrinolytic plasminogen activator inhibitor activity, was higher in patients than in control subjects (median 19.2 versus 6.3 U/mL); 61% of patients had high plasminogen activator inhibitor activity (> or = 16.4 U/mL) versus 5% of control subjects. Stimulated tissue plasminogen activator activity (inhibited by plasminogen activator inhibitor activity) was lower in patients than in control subjects (3.10 versus 5.98 IU/mL); 31% of patients had low stimulated tissue plasminogen activator activity (< 2.28 IU/mL) versus 3% of control subjects. Heritable hypofibrinolysis conferred by the 4G/4G mutation of the plasminogen activator inhibitor-1 gene seems to be a major pathoetiology of primary osteonecrosis.

Adult↗

Achiral and chiral HPLC analysis of norverapamil and its metabolites in microsomal samples.

Achiral and chiral HPLC (high performance liquid chromatography) were developed for monitoring norverapamil and its two metabolites in in vitro microsomal samples. Norverapamil is a chiral drug with the same ability as verapamil in reversing MDR (multi-drug resistance) against some cytostatics. R(+) norverapamil is less cardiotoxic as S(-) enantiomer and so it could be applied in higher concentrations. HPLC conditions were worked out for both achiral and chiral assays and very simple and effective preseparation procedure (SPE - solid phase extraction) was used for microsomal sample as clean-up step before HPLC analysis. The total concentrations of norverapamil and its metabolites were calculated from achiral chromatograms and the ratio of enantiomers were determined from chiral separations. The complete assay could be used for both in vitro and in vivo experiments.

Biotransformation↗

A preliminary pilot study of treatment of thrombophilia and hypofibrinolysis and amelioration of the pain of osteonecrosis of the jaws.

OBJECTIVES: In a preliminary pilot study of 30 treatments in 26 patients with osteonecrosis of the jaws and chronic disabling facial pain, our specific aim was to determine whether, to what degree, and how safely therapy of hypofibrinolysis and thrombophilia would ameliorate the chronic pain associated with osteonecrosis of the mandible and maxilla. STUDY DESIGN: Thrombophilia was treated with Coumadin (DuPont) in 10 patients; hypofibrinolysis was treated with Winstrol (Sanofi-Winthrop) in 20 patients, including 4 who had mixed thrombophilia and hypofibrinolysis and had previously been treated with Coumadin. The initial treatment period was targeted to be 4 months. Each patient was asked to keep a daily written pain-relief numeric rating score and side-effects diary and to provide a summary pain-relief numeric rating score and side effects compilation for the total treatment period. RESULTS: There were 4 men and 22 women in the study group; their mean age was 49 +/- 11 years. The mean onset of their osteonecrosis pain was at age 45 +/- 12 years, and the mean duration of their facial pain prior to therapy was 4.5 +/- 4.2 years. Ten patients had one or more thrombophilic traits (there were two patients with protein C deficiency, five with resistance to activated protein C and/or the mutant Factor V Leiden gene, and four with high anticardiolipin antibodies). The 10 patients who were thrombophilic were treated with Coumadin (the international normalized ratio was targeted to 2.5-3.0) for 22 +/- 9 weeks. By self-reported pain-relief numeric rating scores, 6 of the 10 patients with thrombophilia (60%) had > or = 40% pain relief, 2 (20%) had no change, and 2 (20%) had increased pain (30% and 80% worse). Nine of the 10 patients with thrombophilia (90%) had no Coumadin-related side effects; 1 patient (10%) stopped Coumadin therapy (after 28 weeks) because of nosebleeds. Winstrol (6 mg per day) was used for 16 +/- 9 weeks in 20 patients with hypofibrinolysis, some of whom had one or more hypofibrinolytic traits (10 had high levels of plasminogen activator/inhibitor activity, usually accompanied by low stimulated tissue plasminogen activator activity; 13 had high Lp[a] lipoprotein). Of these 20 patients with hypofibrinolysis, 9 patients (45%) had > or = 40% pain relief, 3 patients (15%) had 20% to 30% relief, 5 patients (25%) had no improvement, and 3 patients (15%) had increased pain (30% worse, 60% worse, and 70% worse). Six of the 20 patients with hypofibrinolysis (30%) had no Winstrol-related side effects, while 14 (70%) had side effects that could be attributed to Winstrol, including weight gain, peripheral edema, increased facial and body hair, and acne--all of which were reversed within 6 weeks of stopping Winstrol therapy. CONCLUSIONS: We postulate that thrombophilia and hypofibrinolysis lead to impaired venous circulation and venous hypertension of the mandible/maxilla with subsequent development of osteonecrosis and chronic facial pain. In many patients, facial pain can be ameliorated by treating the pathogenetic coagulation defects with Coumadin or Winstrol. Large, double-blind, placebo-controlled crossover studies will be required in the future to validate these preliminary results and to determine whether pain relief with Coumadin or Winstrol justifies the risks and side effects associated with these medications, especially for long-term use, in osteonecrosis of the jaws.

Adult↗

Reduction of the Human Placental Vascular Relaxation to Progesterone by Gestational Diabetes

>Background: We have recently described a dose-dependent, endothelium-independent relaxation to progesterone in human placental arteries and veins. This receptor-operated, cAMP-mediated relaxation may be of value in maintaining adequate blood flow in the placental circulation.Objective: To investigate if gestational diabetes alters this relaxation to progesterone.Study design: Isolated human placental vessels from pregnancies complicated by gestational diabetes and well matched controls (uncomplicated term pregnancies), incubated in Krebs-bicarbonate buffer and submaximally precontracted with KCl, were exposed to cumulative doses of progesterone (0.01-30 µmol/liter), nitroglycerin (0.001-1 µmol/liter), arachidonic acid (0.01-10 µmol/liter), forskolin (0.01-10 µmol/liter) and 5-hydroxytryptamine (serotonin, 0.01-10 µmol/liter).Results: The relaxation to progesterone in vessels from patients with gestational diabetes was reduced by 50-100% in both arteries and veins compared with control (for example, relaxation to 10 µmol/liter progesterone was reduced from 52 +/- 7 to 18.8 +/- 5.4% in arteries and from 58 +/- 8 to 19 +/- 5.2% in veins, n = 7-13, P < 0.05), whereas responses to the other vasoactive agents were unchanged.Conclusion: Based on these results, gestational diabetes significantly reduces the relaxation to progesterone in human placental vessels. This alteration of the relaxation to progesterone may lead to an increase in placental vascular resistance and possibly to a reduction of placental blood flow.

Journal Article↗

Secondhand smoke, hypofibrinolysis, and Legg-Perthes disease.

In 39 children with Legg-Perthes disease who were nonsmokers, the specific aim was to assess relationships among parental cigarette smoking during pregnancy, household smoking before diagnosis of Legg-Perthes disease, hypofibrinolysis, and thrombophilia. Fifteen (38%) children had no secondhand smoke exposure; 24 (62%) had secondhand smoke exposure before their diagnosis. Seventeen (71%) of these 24 children were exposed while in utero to smoking by a parent or live in relative and also had exposure to household smoke during childhood; seven (29%) had only household smoke exposure in childhood. In the full cohort of 39 children, secondhand smoke exposure correlated inversely with the major stimulator of fibrinolysis, stimulated tissue plasminogen activator activity. Of the children exposed to smoking, 48% had low stimulated tissue plasminogen activator activity (< 2.19 IU/ml) compared with 7% of the children without secondhand smoke exposure and 14% of 22 healthy control children. Secondhand smoke exposure had no significant effects on other measures of coagulation. Secondhand smoke exposure while in utero and during childhood appears to lower stimulated tissue plasminogen activator activity and additionally may depress heritable low stimulated tissue plasminogen activator activity, leading to hypofibrinolysis. Hypofibrinolysis may facilitate thrombotic venous occlusion in the head of the femur, leading to venous hypertension and hypoxic bone death, Legg-Perthes disease.

Adult↗

Resistance to activated protein C and Legg-Perthes disease.

Thrombophilia may cause thrombotic venous occlusion in the femoral head, with venous hypertension and hypoxic bone death, leading to Legg-Perthes disease. Resistance to activated protein C, the most common thrombophilic trait, was measured in 64 children with Legg-Perthes disease. Genomic deoxyribonucleic acid was studied to delineate the CGA-->CAA substitution at position 1691 of the Factor V Leiden gene responsible for resistance to activated protein C. The activated protein C ratio was calculated by dividing clotting time obtained with activated protein C-calcium chloride by clotting time obtained with calcium chloride alone. Resistance to activated protein C, with a low activated protein C ratio (less than 2.19, the 5th percentile for 160 normal pediatric controls) was the most common coagulation defect, found in 23 of 64 children with Legg-Perthes disease versus 7 of 160 pediatric controls. Eight of 64 children with Legg-Perthes disease had a low activated protein C ratio and the mutant Factor V gene (7 heterozygotes, 1 homozygote) versus 1 of 101 normal pediatric controls. Two or 3 generation vertical and horizontal transmission of heterozygosity for the mutant Factor V gene was found in 4 of the 8 kindreds. Of 64 children with Legg-Perthes disease, only 14 (22%) had entirely normal coagulation measures. Resistance to activated protein C appears to be a pathogenetic cause of Legg-Perthes disease.

Blood Coagulation Disorders↗

Differential expression of the major histocompatibility antigens and ICAM-1 on bile duct epithelial cells in biliary atresia.

Aberrant expression on biliary epithelial cells of the major histocompatibility complex (MHC) antigens in association with adhesion molecule intercellular adhesion molecule-1 (ICAM-1) may be crucial to the immunopathogenesis of biliary atresia. The patterns of MHC class I and II expression in relation to ICAM-1 expression as well as the associated lymphocyte subpopulations were studied in frozen section liver biopsies from six infants with biliary atresia. Intense ICAM-1 expression was found on all ductal epithelial cells in association with MHC I. No ductal epithelial cells demonstrated MHC II expression. Lymphocyte populations within the portal tracts all expressed LFA-1 and were predominantly CD4 positive (> 70%). CD8 positive cells accounted for less than 30%. The expression of ICAM-1 appears to be important in the pathogenesis of biliary atresia but is not linked to the expression of MHC II determinants. This result suggests that different regulatory mechanisms govern the expression of these important immunological receptors on biliary epithelial cells.

Bile Ducts↗