Biomedical subjects

G Fernandez

Publications and source records attributed to G Fernandez.

At least 19 recordsLinked to original sources

PubMed2006

Organochlorine compounds and stable isotopes indicate bottlenose dolphin subpopulation structure around the Iberian Peninsula.

Isotopic signatures and organochlorine pollutant loads of organisms reflect the characteristics of the waters in which they live and feed. To investigate population structure of bottlenose dolphins around the Iberian Peninsula we determined delta(13)C and delta(15)N in the skin and organochlorine (OC) levels in the blubber of stranded bottlenose dolphins inhabiting the Mediterranean (Catalonia, Valencia and Balearic Islands) and adjacent Atlantic waters (Huelva and Portugal). OC levels were high in all regions, reflecting the predatory habits of the species, its coastal distribution and the existence of intense agricultural and industrial activity throughout the region. PCB congeners showed a gradient from the relatively more chlorinated forms to those that are less so, and followed a northeast to northwest direction across the Iberian Peninsula. This suggests that PCB inputs are more recent in the temperate latitudes of the eastern Atlantic Ocean than in the western Mediterranean Sea. Comparatively, OC ratios and isotopic signatures proved to be more efficient ways of discriminating groups than did raw OC concentrations. Significant differences in delta(13)C and in PCB congener profiles indicate that dolphins from the Atlantic and the Mediterranean do not intermingle. In addition, the two Atlantic groups differed in delta(15)N signature, tDDT concentration, DDT/PCB ratio and the PCB congener profile, which also suggests some degree of isolation between them. In the Mediterranean, dolphins from Catalonia and Valencia were indistinguishable, suggesting a common distribution area. However, dolphins from the Balearic Islands differed from those of the Peninsula in their DDT/PCB ratio and from all the other sample groups in their PCB congener profiles, which supports the hypothesis that the deep waters between the Islands and the Peninsula represent an effective barrier for the species.

Animals↗

PubMed2004

Involvement of an unnamed protein, RDA288, in the mechanism through which progesterone mediates its antiapoptotic action in spontaneously immortalized granulosa cells.

Progesterone (P4) inhibits apoptosis of rat granulosa cells and spontaneously immortalized granulosa cells (SIGCs), which were derived from rat granulosa cells. Defining the mechanism through which P4 mediates its action has been difficult because these cells do not express the classic nuclear P4 receptor. Previous studies have shown that a P4 receptor antibody, C-262, detects a 60-kDa protein that is involved in regulating P4's antiapoptotic action. Using a C-262 affinity column, this 60-kDa protein was isolated and sequenced by mass spectrometry. This analysis revealed that the C-262-detectable protein is an unnamed protein referred to as RDA288. This protein has several putative hyaluronic acid binding sites. Further hyaluronic acid antagonizes (3)H-P4 binding to SIGCs and mimics P4's action, whereas exogenous hyaluronic acid binding protein attenuates P4's actions. RT-PCR demonstrated that RDA288 mRNA was present in SIGCs, immature rat ovary, lung, and skeletal muscle but was not present in several other organs. Forced expression of RDA288 increased the capacity of SIGCs to bind and respond to P4. An antibody was also developed against RDA288. Using this antibody in a Western blot protocol, RDA288 expression was confirmed in both SIGCs and granulosa cells. An immunohistochemical study detected RDA288 in the cytoplasm and plasma membrane components of granulosa cells of antral follicles. Immunocytochemical studies on living nonpermeabilized SIGCs revealed that RDA288 was present on the extracellular surface of the plasma membrane. Finally, pretreatment with the RDA288 antibody blocked P4's antiapoptotic actions. Taken together, these data suggest that RDA288 plays a significant role in mediating P4's antiapoptotic action in granulosa cells.

Amino Acid Sequence↗

PubMed2004

Longitudinal prescribing patterns for psychoactive medications in community-based individuals with developmental disabilities: utilization of pharmacy records.

BACKGROUND: Little is known about longitudinal prescribing practices for psychoactive medications for individuals with intellectual disabilities and developmental disabilities (IDDD) who are living in community settings. METHODS: Computerized pharmacy records were accessed for 2344 community-based individuals with IDDD for whom a total of 3421 prescriptions were written during a 17-month period of study. Forty-two psychoactive medications were rank ordered in terms of prescription frequency. RESULTS: Fifty-two per cent (52%) of all prescriptions written during the study period were for psychoactive medications. Anticonvulsant, antipsychotic and antidepressant medications were the most commonly filled prescriptions among psychoactive medications. Sixty per cent (62%) of the study population was given prescriptions for more than one psychoactive medication and 36% received three or more psychoactive medications. During the study period there was a statistically significant increase in prescriptions filled for olanzapine, risperidone, valproic acid, and clonazepam whereas prescriptions filled for thioridazine, haloperidol, and benzotropine showed a significant decline (P < 0.05-0.001). Distribution of psychoactive drug class by age showed that the majority of prescriptions were filled for individuals between 20 and 50 years with the exception of prescriptions for psychostimulants which peaked for individuals prior to 20 years. CONCLUSIONS: (1) Analysis of pharmacy billing records provides a method for assessing prescribing patterns of psychoactive medications in community-based individuals with IDDD. (2) Polypharmacy for psychoactive medications is prevalent in this setting. (3) The second-generation antipsychotic medications are prominently represented by an increasing number of filled prescriptions during the study period.

Adult↗

PubMed2004

Efficacy of a commercial mycotoxin binder in alleviating effects of ochratoxin A, fumonisin B1, moniliformin and zearalenone in adult mink.

The addition of nutritionally inert adsorbents to mycotoxin-contaminated animal feed has been a popular approach to decreasing toxicity in animals and carryover of mycotoxins from contaminated feed to animal by-products. Some studies suggest that esterified glucomannan derived from the cell wall of Saccharomyces cerevisiae is effective in reducing the bioavailability of at least some of the mycotoxins occurring in contaminated feed. Because cereal grains are important components of ranch mink diets, mycotoxicoses in mink is a potential problem faced by mink ranchers. We conducted a series of studies to determine if inclusion of a commercially available esterified glucomannan in ranch mink feed was effective in alleviating clinical signs indicative of exposure to ochratoxin A, fumonisin B1, moniliformin or zearalenone in adult mink. In 4 separate trials, mink were fed diets that contained 2.5, 5 or 10 mg ochratoxin A/kg feed, 200 mg fumonisin B1/kg feed, 20 mg moniliformin/kg feed, or 30 mg zearalenone/kg feed with or without 2 g esterified glucomannan/kg feed. Male mink fed diets containing ochratoxin A had significantly decreased feed intake as well as renal lesions characteristic of exposure to that mycotoxin. Inclusion of the esterified glucomannan did not ameliorate these effects. Male mink exposed to fumonisin B1 had increased urinary sphinganine concentration, which was not significantly reduced by the mycotoxin adsorbent. Male mink that consumed monilformin-contaminated diets had characteristic ultrastructural changes in the heart that were not reduced in severity by the esterified glucomannan. Female mink exposed to zearalenone had increased uterine weight, which was not reversed by inclusion of commercial mycotoxin binder in the contaminated feed. The results of this study suggest that a commercial esterified glucomannan was generally ineffective in alleviating effects indicative of exposure to ochratoxin A, fumonisin B1, monilformin and zearalenone in mink.

Adsorption↗

PubMed2003

Expression pattern and role of a 60-kilodalton progesterone binding protein in regulating granulosa cell apoptosis: involvement of the mitogen-activated protein kinase cascade.

Progesterone (P4) inhibits both granulosa cells and spontaneously immortalized granulosa cells (SIGCs) from undergoing apoptosis. P4 does so through a plasma membrane-initiated event. It appears that P4's membrane-initiated actions are mediated by a 60-kDa P4 binding protein (P4BP), which is detected by an antibody directed against the ligand binding domain of the nuclear P4 receptor (i.e., C-262). Immunohistochemical analysis revealed that a C-262-detectable protein was first observed in the periphery of a few granulosa cells within early antral-stage follicles. In nonatretic antral follicles, this protein was detected at the periphery of virtually all granulosa cells. In contrast, granulosa cells of atretic follicles lost the distinct peripheral localization of this C-262-detectable protein. This reduction in the membrane localization was also observed by Western blot analysis. To assess the temporal changes in this 60-kDa P4BP during apoptosis, studies were conducted using SIGCs. That this 60-kDa protein is important in mediating P4's action was confirmed by the observation that C-262 but not IgG attenuated P4's antiapoptotic action. Interestingly, the membrane localization of this 60-kDa P4BP was maintained but the ability of P4 to prevent apoptosis was lost within 20 min of initiating the apoptotic cascade. In addition, Erk-1 and -2 phosphorylation (i.e., activity) increased within 20 min of P4 withdrawal. Further, P4 suppressed the increase in the Erk-1 phosphorylation if administered within 5 but not 20 min of initiating the apoptotic cascade. Moreover, the mitogen-activated protein kinase kinase (MEK) inhibitor, PD98059, reduced the percentage of SIGCs undergoing apoptosis in the absence of P4. Because MEK phosphorylates Erk, these observations suggests that 1) the increase in Erk-1 activity is an important part of the apoptotic cascade, 2) P4 promotes granulosa cell viability by modulating the activity of Erk-1, and 3) P4 becomes "uncoupled" from its antiapoptotic signal transduction mechanism within 20 min of initiating apoptosis, even though the membrane localization of the 60-kDa P4BP is maintained.

Animals↗

PubMed2002

Membrane-initiated events account for progesterone's ability to regulate intracellular free calcium levels and inhibit rat granulosa cell mitosis.

It has been proposed that the antimitogenic action of progesterone (P(4)) is mediated through a membrane receptor that has GABA(A) receptor-like characteristics. To test this hypothesis, studies were designed to compare the antimitogenic effects of P(4) with its gamma amino butyric acid(A) (GABA(A)) receptor-activating metabolite, 5alpha-pregnane-3alpha-21-diol-20-one (5alpha3alpha). These studies revealed that P(4) was more effective than 5alpha3alpha in blocking mitogen-dependent mitosis of both small granulosa cells (GCs) and spontaneously immortalized granulosa cells (SIGCs). Ligand binding studies illustrated that P(4) bound to SIGCs with an apparent dissociation constant (K(d)) of 0.32 +/- 0.09 microM, whereas 5alpha3alpha bound with an apparent K(d) of 40 +/- 19 microM. Further, the GABA(A) antagonist, bicuculline, did not attenuate P(4)'s antimitotic action in SIGCs. Finally, reverse transcriptase-polymerase chain reaction (RT-PCR) studies demonstrated that none of the 6 known alpha chains of the GABA(A) receptors to which bicuculline binds were detected in SIGCs. Taken together, these studies suggest that P(4) does not mediate its action via a GABA(A)-like receptor. Additional studies revealed that P(4) regulated intracellular free calcium levels ([Ca(2+)](i)) as part of its antimitotic action. Specifically, P(4) maintained a basal [Ca(2+)](i) level that was slightly lower than normal. Increasing extracellular calcium not only increased basal [Ca(2+)](i) but also attenuated P(4)'s antimitogenic effect. P(4)'s actions appeared to be initiated at the membrane, since horseradish peroxidase conjugated-P(4) (HP-P(4)), which is cell impermeable, was as effective in blocking mitosis as P(4). Progesterone receptor (PR) mRNA was not detected in SIGCs by RT-PCR analysis, which is consistent with the findings in GCs. However, a 60-kDa protein was detected within crude membrane fractions of both GCs and SIGCs using an antibody directed against the ligand binding domain of the PR (C-262). This antibody was also used in immunocytochemical studies to detect a protein that was associated with the plasma membrane of SIGCs. It is proposed that this 60-kDa protein mediates P(4)'s membrane-initiated actions.

Animals↗

PubMed2001

Immune complexes (IC) down-regulate the basal and interferon-gamma-induced expression of MHC class II on human monocytes.

The interaction of Fc receptors for IgG (FcgammaRs) on monocytes/macrophages with immune complexes (IC) triggers regulatory and effector functions. Previous studies have shown that FcgammaR-IC interactions inhibit the IFN-gamma-induced expression of MHC class II in murine macrophages. However, the mechanism(s) responsible for these effects have not been elucidated. In addition, whether this IC-dependent effect also occurs in human cells is not known. Taking into account the fact that IC and IFN-gamma are frequently found in infections and autoimmune disorders, together with the crucial role MHC class II molecules play in the regulation of immune response, we explored the effect and mechanism of IC-induced MHC class II down-regulation in human peripheral blood mononuclear cells (PBMC). This effect was studied either in the presence or absence of IFN-gamma. We demonstrate that IC exert a drastic inhibition of basal and IFN-gamma-induced expression of MHC class II on human monocytes. This effect was mediated through the interaction of IC with both FcgammaRI and FcgammaRII. Moreover, similar results were obtained using supernatants from IC-treated PBMC. The IC-induced down-regulation of MHC class II is abrogated by pepstatin and phosphoramidon, supporting the role of aspartic protease(s) and metalloprotease(s) in this process. In parallel with MHC class II expression, antigen presentation was markedly inhibited in the presence of IC.

Antigen Presentation↗

PubMed2001

Estrogenic status influences nitric oxide-regulated TNF-alpha release from human peripheral blood monocytes.

Cytokines and nitric oxide (NO) have been implicated in bone loss caused by estrogen deficiency. Here we evaluated the effect of nitric oxide synthase (NOS) inhibitors on the bone particle resorbing activity and TNF-alpha release of cultured peripheral blood monocytes (PBM) obtained from 10 premenopausal (PreM) and 10 postmenopausal (PostM) women. Gonadal status (menopause < 3 yr) was assessed by FSH and estradiol. Bone alkaline phosphatase and N-Telopeptide were significantly increased in PostM. Significant differences between PreM and PostM women were observed in bone mineral density of lumbar spine. The bone particle resorbing activity of PBM cultured in the presence of L-arginine-methyl ester (NAME) or aminoguanidine, NOS inhibitors, was determined by (45)Ca release from rat bone labeled particles. TNF-alpha release was assayed in supernatants by ELISA. (45)Ca release was higher in PostM (p < 0.01) and was enhanced by NAME (p < 0.02). Furthermore, TNF-alpha release from PBM was significantly higher in PostM (p < 0.01). Aminoguanidine significantly increased TNF-alpha release in PreM. Based on these findings and on the evidence that estrogen stimulates NOS, we suggest that estrogen withdrawal may reduce the inhibitory effect of NO on TNF-alpha release. Thus, this increased production of TNF-alpha could contribute to the increased postmenopausal bone turnover.

Adult↗

PubMed2001

E-cadherin-mediated cell contact prevents apoptosis of spontaneously immortalized granulosa cells by regulating Akt kinase activity.

The present studies were designed to determine the role that homophilic E-cadherin binding plays in preventing apoptosis of spontaneously immortalized granulosa cells (SIGCs). Although the levels of E-cadherin were similar to serum control levels, the amount of E-cadherin at the plasma membrane was dramatically reduced by 5 h after serum withdrawal. To determine whether disrupting homophilic E-cadherin binding leads to apoptosis, SIGCs were cultured in serum in the presence of either EGTA or an E-cadherin antibody. Treatment with either EGTA, which disrupts all calcium-dependent contacts, or E-cadherin antibody, induced apoptosis. Exposure to EGTA reduced MEK and Akt kinase activity, whereas E-cadherin antibody only attenuated Akt kinase activity. Because Akt kinase controls caspase-3 activity, an important activator of apoptosis, caspase-3 activity was monitored. Caspase-3 activity increased after serum depletion, or EGTA or E-cadherin antibody treatment. Time-series analysis of caspase-3 activity within single cells revealed that during apoptosis cell contact was disrupted then caspase-3 activity was detected. Finally, the caspase inhibitor, Z-VAD-FMK, blocked apoptosis. These data taken together are consistent with the concept that E-cadherin-mediated cell contact, either directly or indirectly, promotes Akt kinase activity, which in turn, inhibits caspase-3 activation and thereby maintains SIGC viability.

Amino Acid Chloromethyl Ketones↗

PubMed2001

Characterization of a putative membrane receptor for progesterone in rat granulosa cells.

Progesterone (P(4)) inhibits granulosa cell apoptosis in a steroid-specific, dose-dependent manner, but these cells do not express the classic nuclear P(4) receptor. It has been proposed that P(4) mediates its action through a 60-kDa protein that functions as a membrane receptor. The present studies were designed to determine the P(4) binding characteristics of this protein. Western blot analysis using an antibody that recognizes the P(4) binding site of the nuclear P(4) receptor (C-262) confirmed that the 60-kDa protein was localized to the plasma membrane of both granulosa cells and spontaneously immortalized granulosa cells (SIGCs). To determine whether this protein binds P(4), proteins were immunoprecipitated with the C-262 antibody, electrophoresed, transferred to nitrocellulose, and probed with a horseradish peroxidase-labeled P(4) in the presence or absence of nonlabeled P(4). This study demonstrated that the 60-kDa protein specifically binds P(4). Scatchard plot analysis revealed that (3)H-P(4) binds to a single site (i.e., single protein), which is relatively abundant (200 pmol/mg) with a K(d) of 360 nM. (3)H-P(4) binding was not reduced by dexamethasone, mifepristone (RU 486), or onapristone (ZK98299). Further studies with SIGCs showed that P(4) inhibited apoptosis and mitogen-activated protein kinase kinase (MEK) activity, and maintained calcium homeostasis. These studies taken together support the concept that the 60-kDa P(4) binding protein functions as a low-affinity, high-capacity membrane receptor for P(4).

Animals↗

PubMed2001

Basic fibroblast growth factor maintains calcium homeostasis and granulosa cell viability by stimulating calcium efflux via a PKC delta-dependent pathway.

Previous studies have demonstrated that basic fibroblast growth factor prevents granulosa cell apoptosis. The following six observations provide insight into the mechanism by which basic fibroblast growth factor mediates its antiapoptotic action. First, loading granulosa cells with 1,2 bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, an intracellular calcium chelator, prevented apoptosis when granulosa cells were deprived of basic fibroblast growth factor. Second, treatment with thapsigargin, an agent known to increase intracellular free calcium, induced granulosa cell apoptosis even in the presence of basic fibroblast growth factor. Third, an activator of PKC mimicked, whereas PKC inhibitors blocked, basic fibroblast growth factor's antiapoptotic action. Fourth, continuous basic fibroblast growth factor exposure maintained relatively constant levels of intracellular free calcium, and a PKC inhibitor induced a sustained 2- to 3-fold increase in intracellular free calcium. Fifth, granulosa cells, as well as spontaneously immortalized granulosa cells, were shown to express PKC delta, -lambda, and -zeta. Finally, the PKC delta-specific inhibitor, rottlerin, blocked basic fibroblast growth factor's antiapoptotic action in granulosa cells and spontaneously immortalized granulosa cells. These studies suggest that basic fibroblast growth factor regulates intracellular free calcium through a PKC delta-dependent mechanism and that a sustained increase in intracellular free calcium is sufficient to induce and is required for granulosa cell apoptosis. Additional studies demonstrated that in spontaneously immortalized granulosa cells, basic fibroblast growth factor increased PKC delta activity by 60% within 2.5 min compared with serum-free control levels. Rottlerin attenuated basic fibroblast growth factor's ability to stimulate PKC delta activity and to maintain intracellular free calcium. Further, intracellular free calcium levels in spontaneously immortalized granulosa cells transfected with a PKC delta antibody in the presence of basic fibroblast growth factor were 2-fold higher than those spontaneously immortalized granulosa cells transfected with IgG. Similarly, transfecting spontaneously immortalized granulosa cells with a specific PKC delta-substrate increased intracellular free calcium compared with spontaneously immortalized granulosa cells transfected with a specific substrate for PKC epsilon. Moreover, basic fibroblast growth factor increased and rottlerin attenuated (45)Ca efflux by 50% compared with that in basic fibroblast growth factor-treated cells. Finally, an inhibitor of the plasma membrane calciumadenosine triphosphatase pump suppressed (45)Ca efflux, elevated intracellular free calcium, and induced apoptosis. Collectively, these studies demonstrate that basic fibroblast growth factor activates PKC delta, which, in turn, stimulates calcium efflux, accounting in part for basic fibroblast growth factor's ability to maintain calcium homeostasis and, ultimately, granulosa cell viability.

Animals↗

PubMed2001

Traumatic perforation of the tympanic membrane.

Traumatic perforations of the ear drum are often encountered in the emergency room and in the primary care setting. We review mechanisms of injury to the tympanic membrane and elucidate the appropriate evaluation and treatment of this injury.

Humans↗

PubMed2001

Influence of HLA-DR alleles on rheumatoid arthritis: susceptibility and severity in Argentine patients.

OBJECTIVE: To determine the frequency of shared epitopes in our population of patients with rheumatoid arthritis (RA) and to investigate whether the presence of these alleles is associated with a more aggressive form of disease. METHODS: Demographic and clinical data were obtained from 140 patients with RA, 123 female, mean age 49.9+/-11.7 years and mean disease duration 9.4+/-6.3 years. Radiographs of both hands were taken and scored by Larsen's method. HLA-DR alleles were determined by PCR-SSP. The control group comprised 202 healthy ethnic-matched subjects. RESULTS: DR4 was significantly more frequent in patients with RA than controls, and was observed in 70/140 patients (50%) versus 47/202 controls (23.27%) (odds ratio 3.25, CI 1.99-5.35, Pcorr 5 x 10(-5)). Within DR4 subtypes *0404 and *0401 were the most commonly found (37.7 and 29%, respectively). DR3 and DR11 exerted a protective effect with significantly higher frequency in controls than in patients with RA. When patients were divided into 2 groups according to disease severity (radiographic score) the frequency of alleles with QKRAA and QRRAA sequences was similar in both groups. Although with lower frequency, subtype *1001 alone was significantly more frequent in the severe-condition group [7 (13.5%) vs 3 (3.4%), p = 0.03]. CONCLUSION: These results are in accordance with findings observed in Caucasians and differ from other Latin American populations. However shared epitope alleles failed to correlate with more severe disease with the exception of subtype *1001 which, although infrequent, was significantly more frequent in patients with relevant radiological damage.

Adult↗

PubMed2001

CT findings associated with Eagle syndrome.

Eagle syndrome is an aggregate of symptoms caused by an elongated ossified styloid process, the cause of which remains unclear. This is a rare finding that often goes undetected in the absence of radiographic studies. In this case, we present the diagnostic CT and lateral view plain film radiography findings of a 39-year-old woman with clinical evidence of Eagle syndrome. Eagle syndrome can occur unilaterally or bilaterally and most frequently results in symptoms of dysphagia, headache, pain on rotation of the neck, pain on extension of the tongue, change in voice, and a sensation of hypersalivation (1, 2). We present rare and diagnostic radiographic evidence of this on both plain film radiographs and CT scans. Although well documented in otolaryngology literature and dentistry literature, this syndrome has not been reported in the radiology literature.

Adult↗

PubMed2000

Invasive carcinoma in clinically suspicious breast masses diagnosed as adenocarcinoma by fine-needle aspiration.

BACKGROUND: Fine-needle aspiration (FNA) biopsy of palpable breast masses along with clinical and radiologic findings can provide rapid distinction between benign and malignant lesions. A preoperative determination of invasive or in situ carcinoma assists in the planning of definitive treatment. Previous studies have concentrated on whether cytologic features adequately distinguish invasion, but to the authors' knowledge the predictive value of clinicopathologic correlation has not been investigated. The authors attempted to determine whether a malignant cytologic diagnosis for a palpable breast mass is sufficient for its definitive surgical management as an invasive neoplasm. METHODS: The authors reviewed 351 FNAs from palpable breast lesions with a cytologic diagnosis of "adenocarcinoma." The presence of invasive disease was determined by histologic demonstration of invasive carcinoma in the corresponding surgical specimen or by identifying metastatic carcinoma in the absence of another primary source. RESULTS: Three hundred forty-three (97.7%) palpable tumors diagnosed as adenocarcinoma by FNA proved to be invasive adenocarcinoma. The remaining eight tumors contained high grade ductal carcinoma in situ, and two of these contained foci suggestive of microinvasion. CONCLUSIONS: A palpable breast mass with an FNA diagnosis of adenocarcinoma usually represents invasive carcinoma. A definitive treatment plan therefore can be planned based on these clinical and FNA findings.

Adenocarcinoma↗

PubMed2000

Enhancement of hydralazine hypotension by low doses of isoniazid. Possible role of semicarbazide-sensitive amine oxidase inhibition.

The influence of pretreatment with 1 through 300 mg/kg ip of isoniazid (ISO) on blood pressure and heart rate responses to 0.1 mg/kg iv of hydralazine (HYD) was assessed in rats anesthetized with chloralose--urethane. HYD hypotension was significantly enhanced by ISO at doses between 3 and 300 mg/kg ip. Heart rate was not influenced by HYD in control or pretreated animals. Depressor responses to 0.2 mg/kg iv of pinacidil (PIN) were also potentiated by ISO at 100 and 300, but not at 30 mg/kg. Similarly, ISO decreased cerebral gamma-aminobutyric acid (GABA) at the two highest doses; 30 mg/kg was without effect. Pretreatment of rats with ISO at 1 through 300 mg/kg failed to influence HYD-induced relaxation of aortic rings. These results were interpreted as indicating that potentiation of HYD hypotension by high doses of ISO is not specific for that vasodilator and is related to decreased cerebral GABA, as postulated previously. Lower doses could specifically potentiate the HYD-induced hypotensive effect by inhibition of semicarbazide-sensitive amine oxidase (SSAO), since both ISO and HYD are potent inhibitors of this enzyme. In support of this hypothesis, the SSAO inhibitors, benserazide (100 mg/kg ip) and mexiletine (50 mg/kg ip), were also found to enhance HYD hypotension.

Amine Oxidase (Copper-Containing)↗

PubMed2000

Basic fibroblast growth factor inhibits apoptosis of spontaneously immortalized granulosa cells by regulating intracellular free calcium levels through a protein kinase Cdelta-dependent pathway.

Previous studies have shown that basic fibroblast growth factor (bFGF) inhibits primary granulosa cells from undergoing apoptosis. The present studies were designed to determine whether spontaneously immortalized granulosa cells (SIGCs) undergo apoptosis when deprived of growth factors and whether bFGF prevents apoptosis. In the absence of serum, the SIGCs lost cell contact and underwent apoptosis as indicated by the presence of annexin V binding, DNA ladders, and nuclear fragmentation. Basic FGF maintained cell contact and reduced the percentage of apoptotic cells. This antiapoptotic action was not observed ifbFGF was added 30 min after serum withdrawal. Further, intracellular free calcium ([Ca2+]i) levels gradually increased 3- to 4-fold within 10 min of serum withdrawal. This increase was inhibited by bFGF. The intracellular calcium chelator, BAPTA, completely prevented the SIGCs from undergoing apoptosis in the absence of serum. These observations suggest that bFGF's ability to regulate [Ca2+]i is an essential component of its antiapoptotic action. The phorbol ester TPA, an activator of protein kinase C (PKC), blocked apoptosis due to serum deprivation. Conversely, bisindolylmaleimide II, an inhibitor of PKC, completely attenuated, whereas bisindolylmaleimide V, an inactive bisindolylmaleimide analog, did not influence bFGF's antiapoptotic action. Also, treatment with the PKC inhibitor, chelerythrine chloride, interfered with bFGF's ability to maintain calcium homeostasis. Western blot analysis revealed that SIGCs expressed PKCdelta, tau, lambda, and zeta. Of these PKC isoforms, only PKCdelta has been shown to be activated by TPA. In apoptotic SIGCs, PKCdelta levels were depleted. When PKCdelta levels were reduced by pretreatment with 500 nM TPA, neither bFGF nor 10 nM TPA suppressed apoptosis. Collectively, these observations suggest that bFGF maintains [Ca2+]i and thereby SIGC viability through a PKCdelta-dependent pathway.

Animals↗

PubMed2000

Usefulness of three-dimensional echocardiography for the evaluation of mitral valve prolapse: an intraoperative study.

BACKGROUND AND AIM OF THE STUDY: The study aim was to evaluate the feasibility of intraoperative three-dimensional (3D) transesophageal echocardiography (TEE) in patients referred for mitral valve prolapse (MVP) repair and to compare two-dimensional (2D) TEE and 3D TEE and surgical findings. METHODS: Forty-six patients (mean age 67 +/- 11 years) underwent 3D TEE intraoperatively. Measurements were made of the posterior part of mitral annulus circumference (PMAC), and the width of mitral valve surgical resection on the mitral annulus (WMVR). Using 3D TEE, MVP topography was described, and PMAC in diastole and the width of implantation of MVP on the mitral annulus (WMVP) in systole were measured. RESULTS: 3D TEE was successful in 42 patients (91%). 2D and 3DTEE correctly predicted MVP localization in 38 (90%) and 36 (86%) patients, respectively (p = NS). 3D TEE and surgical PMAC were 89 +/- 13 and 93 +/- 21 mm, respectively (p = 0.01, R = 0.42). WMVR and WMVP were 28 +/- 11 mm and 26 +/- 11 mm, respectively (p <0.0001, R = 0.82). WMVR/anatomic PMAC (0.29 +/- 0.11) and WMVP/3D echo PMAC (0.32 +/- 0.11) were correlated (p <0.0001, R= 0.69). CONCLUSION: Intraoperative 3D TEE evaluation of MVP is feasible. MVP width and its ratio to the mitral annulus were assessed, and found to correlate with surgical findings. These 3D data may be of value to the surgeon when performing mitral valve repair.

Aged↗