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Biomedical subjects

A Shah

Publications and source records attributed to A Shah.

At least 145 records · Page 8Linked to original sources
PubMed1999

Ciprofloxacin concentrations in lung tissue following a single 400 mg intravenous dose.

Intravenous ciprofloxacin is frequently prescribed for the treatment of infections due to nosocomially acquired gram-negative organisms, including those originating in the respiratory tract. In this study, the concentrations of ciprofloxacin in serum and lung tissue were determined by HPLC in patients undergoing lung surgery. A total of 22 patients scheduled for lung surgery received a single 400 mg i.v. dose of ciprofloxacin administered as a 1 h infusion. A specimen of healthy lung tissue was obtained from resected lung from 18 of the patients for analysis of ciprofloxacin concentration during the following time intervals after infusion (one sample/patient): 0-2, 2-4, 4-8 and 8-12 h. Corresponding mean serum and tissue concentrations were 2.37 mg/L and 3.84 mg/kg (0-2 h), 1.18 mg/L and 1.92 mg/kg (2-4 h), 0.69 mg/L and 1.77 mg/kg (4-8 h), and 0.13 mg/L and 0.67 mg/kg (8-12 h). Ciprofloxacin distributed rapidly to lung tissue, as seen by the high concentrations in the lung tissue as early as 2 h after infusion. Concentrations in lung tissue were generally higher than those in serum (tissue:serum ratios ranged from 1.7 to 7.1). The mean tissue concentrations found in this study remained above the MIC for most susceptible organisms.

Adult↗
PubMed1999

Oral bioequivalence of three ciprofloxacin formulations following single-dose administration: 500 mg tablet compared with 500 mg/10 mL or 500 mg/5 mL suspension and the effect of food on the absorption of ciprofloxacin oral suspension.

The oral bioequivalence and tolerability of two ciprofloxacin formulations (tablet and suspension) and the effect of food on the absorption of ciprofloxacin oral suspension were investigated. Sixty-eight young, healthy male subjects participated in two separate, randomized, crossover studies. In study 1, ciprofloxacin as a single 500 mg tablet or as 500 mg/10 mL oral suspension was administered in a fasted state on day 1. In study 2, subjects participated in a three-way crossover study in which ciprofloxacin suspension was administered as 500 mg/10 mL in a fasted state, or 500 mg/10 mL with food, or 500 mg/5 mL in a fasted state. Plasma ciprofloxacin concentrations were measured by high-performance liquid chromatography. Standard pharmacokinetic parameters were estimated using non-compartmental methods. In study 1, geometric mean Cmax values of ciprofloxacin following the single 500 mg tablet and 500 mg/10 mL suspension doses were 2.36 and 2.18 mg/L, respectively; corresponding geometric mean t(max) values were 1.1 and 1.6 h, respectively. Geometric mean AUC(0-infinity) values were 12.0 and 11.8 mg x h/L, respectively. In study 2, geometric least squares mean Cmax values following ciprofloxacin 500 mg/10 mL and 500 mg/5 mL suspension during fasted conditions were 1.54 and 1.59 mg/L, respectively. Corresponding geometric least squares mean AUC(0-infinity) values were 7.3 and 8.0 mg x h/L. Administration of ciprofloxacin 500 mg/10 mL suspension, in either a fasted or fed state, was not associated with significant changes in Cmax (1.54 mg/L for fasted vs 1.37 mg/L for fed) or AUC(0-infinity) values (7.28 mg x h/L for fasted vs 8.19 mg x h/L for fed). Each ciprofloxacin formulation was well tolerated for the duration of each study. These studies demonstrated bioequivalence between ciprofloxacin 500 mg tablet and two strengths of ciprofloxacin suspension (500 mg/10 mL and 500 mg/5 mL). Bioavailability was unaltered by food.

Administration, Oral↗
PubMed1999

Brain activation during intermittent photic stimulation: a [15O]-water PET study on photosensitive epilepsy.

PURPOSE: Intermittent photic stimulation (IPS) is an activation procedure used during electroencephalogram (EEG) recording to elicit paroxysmal discharges in individuals with photosensitivity. Specific responses on EEG recording may be provoked by IPS at different frequencies of flickering in normal individuals and in patients with photosensitive epilepsy. METHODS: Changes in regional cerebral blood flow (rCBF) were studied during IPS in two groups of subjects by using [15O]-water positron emission tomography (PET): a control group consisting of eight healthy adults with photic driving response during IPS on EEG recording (mean age, 25 +/- 10.5 years) without history of neurologic or psychiatric abnormalities and a patient group consisting of four adults (mean age, 33 +/- 7.5 years) with history of photosensitive epilepsy. [15O]-water PET scanning with concomitant EEG monitoring was performed during baseline and IPS at 4-, 14-, and 30-Hz frequencies. RESULTS: The control group showed photic driving response at 14-Hz IPS frequency. The patient group showed photoparoxysmal response at 14 and 30 Hz, but not at 4 Hz. Changes in rCBF were determined by means of statistical parametric mapping. Increases in rCBF in occipital cortex (Brodmann's areas 17, 18, and 19) were observed in both groups. In addition, during photic driving responses, the control group showed rCBF increases in the insula and in the thalamus, on the right side. The patient group showed a significant rCBF increase in the hypothalamic region inferior to the left caudate nucleus during photoparoxysmal response. This activation was not found in the control group. Increased rCBF also was observed in the patient group in the head of the left caudate nucleus, in the left hippocampus, and in left insula during IPS without photoparoxysmal response. No activations in these regions were observed during photoparoxysmal response. CONCLUSIONS: These data may indicate involvement of the hypothalamus in photosensitive epilepsy and may suggest a modulatory function of the caudate nucleus, which might be associated with an inhibition of epileptic discharges during IPS in patients with photosensitive epilepsy.

Adult↗
PubMed1999

Radioaerosol scintigraphy in infants and children born to mothers with HIV disease. Pediatric Pulmonary and Cardiovascular Complications (of Vertically Transmitted Human Immunodeficiency Virus) Study Group.

PURPOSE: To determine the usefulness of technetium 99m diethyltriaminepentacetic acid (DTPA) radioaerosol inhalation-clearance scintigraphy for early detection of pulmonary complications of human immunodeficiency virus (HIV) disease in children. MATERIALS AND METHODS: A total of 301 studies were performed in 132 HIV-positive children (group 1; mean age, 46.6 months). In children born to HIV-positive mothers (group 2), 273 studies were performed in 160 children who eventually were proved to be HIV negative (mean age, 10.3 months), and 80 studies were performed in 47 HIV-positive children (mean age, 15.6 months). Radioaerosol studies were performed by using commercially available radioaerosol nebulizers. Pulmonary clearance half-time was measured by using conventional gamma camera computer systems. Radioaerosol results were correlated with indexes of pulmonary health and function. RESULTS: The HIV-negative, group 2 children had a mean radioaerosol clearance half-time (58.1 minutes; 162 studies in 108 children) similar to that reported in healthy adults. Group 1 children with pulmonary involvement exhibited a faster mean clearance half-time (28.6 minutes) than did children without evidence of pulmonary involvement from either group 1 or group 2 (P < .05). A faster pulmonary clearance rate did not simply reflect the presence of chest disease that also was detectable on radiographs (P = .3). CONCLUSION: Quantitative DTPA radioaerosol clearance studies may provide useful information about pulmonary involvement in selected children with HIV disease.

Administration, Inhalation↗
PubMed1999

Suicide among psychiatric in-patients with schizophrenia in an Australian mental hospital.

Psychiatric in-patient suicides are associated with schizophrenia. In this paper, 62 suicides in patients with schizophrenia, over a 21-year period in a large psychiatric hospital in Melbourne, Australia, were examined. The characteristics, including demographic and clinical data, for the suicides were compared with a comparison group of 22 'alive' in-patients with schizophrenia. Suicide among in-patients with schizophrenia was associated with previous deliberate self-harm, a greater number of episodes of previous deliberate self-harm, pre-admission and intra-admission suicidal thoughts, intra-admission suicidal attempts, fluctuating suicidal ideation, longer length of stay, a greater number of ward transfers, and prescription of a greater number of neuroleptics and antidepressants. Over 40% of suicides occurred after absconding from hospital and a similar number during periods of approved leave. Violent methods (including jumping in front of trains, trams and road traffic, jumping off buildings, hanging and drowning) were most frequently used. It is concluded that psychiatric units should be developed away from readily available methods of suicide. In-patients at high risk should be observed carefully to avoid absconding and suicide. Suicide risk should be examined carefully in patients prior to approving leave, particularly if they have fluctuating suicidal ideation.

Adolescent↗
PubMed1999

The Bournewood judgment: a way forward?

In this article we provide a commentary on the various reasonings behind the Law Lords' unanimous judgements in their recent decision (25 June 1998) in Regina v. Bournewood Community and Mental Health NHS Trust, Ex parte L. After summarizing the judgment and commenting on its important implications, we suggest a way forward. The 1995 Law Commission incapacity proposals, on which the 1997 consultation paper Who Decides? was based, do afford a mechanism which could resolve much of the practical difficulty which practitioners feared from the Appeal Court decision, whilst at the same time affording the sorts of rights which the House of Lords decision denies.

Adult↗
PubMed1999

Altered pharmacokinetics of indinavir by a novel nonnucleoside reverse transcriptase inhibitor (HBY-097): a pharmacokinetic evaluation in HIV-positive patients.

HBY-097 (HBY), an investigational nonnucleoside reverse transcriptase inhibitor (NNRTI), and indinavir (IDV) share a common metabolic pathway, cytochrome P4503A4 (CYP3A4), and may clinically be used together as well as with zidovudine (ZDV). Thus, the potential pharmacokinetic (PK) interaction between these drugs was evaluated. HBY (500 mg Q8H), IDV (800 mg Q8H), and ZDV (200 mg Q8H) were given to 8 HIV-infected subjects. Serial plasma samples were collected at baseline (ZDV and IDV alone) and day 11 (all 3 drugs) to determine PK parameters using noncompartmental analysis. PK parameters for ZDV in the presence and absence of HBY were not appreciably different. However, both the maximum (Cmax) and minimum (Cmin) concentrations of IDV were significantly reduced, from a mean of 7514 +/- 1636 and 146 +/- 81 mcg/L to 4725 +/- 2494 mcg/L and 54 +/- 24 mcg/L (p < .05) after addition of HBY. Furthermore, apparent clearance (CL/F) of IDV before and after 11 days of concomitant HBY administration was significantly higher, from 0.69 +/- 0.14 to 1.94 +/- 0.63 L/h/kg (p < .05) with an associated reduction in area under the curve (AUC0-8) from 16,034 +/- 4903 to 6134 +/- 2701 mg/L/h (p < .05). The increase in IDV CL/F is consistent with the observed metabolic induction effects of other NNRTIs. The results of this trial showed that HBY significantly alters the pharmacokinetic parameters of IDV at the dose studied.

Adult↗
PubMed1999

An optimized strategy for choosing the number of platelet concentrates to pool.

CONTEXT: The number of platelet concentrates (PCs) pooled per dose varies widely. The number should be based on quality control statistics. OBJECTIVE: To determine the optimal number of PCs per pool that will achieve a target dose. DESIGN: The population statistics of PC cell counts were obtained from routine quality control records. A target value of 3.00x10(11) cells was chosen. A theoretical model to predict the probability of achieving this target cell count was developed. MAIN OUTCOME MEASURES: The calculated probability was tested in a Monte Carlo simulation. RESULTS: The mean of a sequential series of 100 PC counts (obtained from routine quality control records) was 9.08x10(10), and the standard deviation was 2.70x10(10). Platelet loss during pooling was measured at 8.3%, so that the pooling of 3.27x10(11) cells is required to deliver a dose of 3.00x10(11) cells. The pooling of 4 PCs from this data set predicts an average pool cell count of 3.63+/-2.30x10(11). Using standard tables for normal distribution, the probability of achieving a minimal pool dose of 3.00x10(11) cells is estimated to be greater than 0.76. Similarly, the probability of achieving the target value by pooling 5 PCs is greater than 0.99. In a Monte Carlo simulation selecting 4 PCs, 76.5% of the trials were successful, and for 5 PCs, 99.5% were successful (estimated P values of .77 and .99, respectively). CONCLUSION: Five PCs per pool are necessary and sufficient to achieve the chosen target value given the cell count characteristics of our PC supply.

Humans↗
PubMed1999

Endometrial response to raloxifene compared with placebo, cyclical hormone replacement therapy, and unopposed estrogen in postmenopausal women.

OBJECTIVE: To determine the endometrial effects of raloxifene 60 mg/day in postmenopausal women as assessed by vaginal bleeding and endometrial thickness. DESIGN: Data from 1157 postmenopausal women were analyzed from a database consisting of four independent, double-blind, randomized, placebo-controlled trials (range = 6-30 months duration), a 24-month open-label randomized, cyclical hormone replacement therapy (HRT)-controlled trial, and a 6-month double-blind, randomized, unopposed estrogen-controlled trial. Vaginal bleeding rate was derived from self-reported adverse events collected at least every 6 months. Endometrial thickness was measured by ultrasonography at regular intervals. RESULTS: Raloxifene 60 mg/day was not significantly different from placebo with regard to the incidence of vaginal bleeding, the baseline-to-endpoint change in endometrial thickness, or the proportion of women experiencing an increase in endometrial thickness above baseline after either 12 or 24 months of therapy. Unexpected bleeding was reported significantly more frequently in the unopposed estrogen groups compared with the raloxifene group (raloxifene 60 mg/day, 0% versus estrogen, 50%; p = 0.002). A significantly greater baseline-to-endpoint increase in endometrial thickness was observed in both the HRT and estrogen groups compared with their respective raloxifene comparison group (raloxifene 60 mg/day, 0.01 +/- 2.0 mm versus HRT, 1.8 +/- 3.2; p < 0.001; raloxifene 60 mg/day, 1.1 +/- 1.7 mm versus estrogen, 7.8 +/- 3.8; p < 0.001). No cases of endometrial hyperplasia or cancer were diagnosed in the placebo or raloxifene 60 mg/day groups. Endometrial hyperplasia was diagnosed in one case in the HRT group and in two cases in the estrogen group. CONCLUSION: Raloxifene 60 mg/day for up to 30 months is not associated with vaginal bleeding or increased endometrial thickness in postmenopausal women.

Aged↗
PubMed1999

Characterization and localization of estrogen and progesterone receptors of human fallopian tube.

The cellular distribution of estrogen and progesterone receptors (ER and PR) in the human fallopian tube was investigated by immunohistochemical localization with specific monoclonal antibodies. Nuclear immunostaining was observed. Intense PR immunostaining was seen in tissues obtained at mid cycle and luteal stages of the normal menstrual cycle. On the other hand, enhanced staining for ER was seen in early follicular phase and mid cycle. Menopausal tissues showed negligible staining for both ER and PR. The ER and PR were characterized for their molecular size, anatomical distribution and levels during the menstrual cycle and in menopause. ER protein was present throughout the cycle and also during menopause. Western blot analysis revealed two forms of ER approximately 66 kDa and a truncated from approximately 49 kDa in hFT. Presence of A [approximately 90 kDa] and B [approximately 120 kDa] isoforms of human PR was detected. Follicular and early luteal tissue possessed relatively high concentration of immunoreactive PR whereas it was almost undetectable in menopausal tissues. These results suggests that ER and PR are regulated by the changing ovarian steroid hormones.

Fallopian Tubes↗
PubMed1999

Modern management of postoperative pain.

In the last 10 years there has been an increased awareness of the need for improved pain management, especially in the postoperative period, to a large extent stimulated by the US Agency for Health Care Policy and Research (AHCPR), which published its clinical practice guidelineS for pain management in 1992. Teams of surgeons, nurses and anesthesiologists now are combining modalities for managing pain so as to provide the most comfortable postoperative course possible for their patients.

Journal Article↗
PubMed1998

Distinct roles for the p110alpha and hVPS34 phosphatidylinositol 3'-kinases in vesicular trafficking, regulation of the actin cytoskeleton, and mitogenesis.

We have examined the roles of the p85/ p110alpha and hVPS34 phosphatidylinositol (PI) 3'-kinases in cellular signaling using inhibitory isoform-specific antibodies. We raised anti-hVPS34 and anti-p110alpha antibodies that specifically inhibit recombinant hVPS34 and p110alpha, respectively, in vitro. We used the antibodies to study cellular processes that are sensitive to low-dose wortmannin. The antibodies had distinct effects on the actin cytoskeleton; microinjection of anti-p110alpha antibodies blocked insulin-stimulated ruffling, whereas anti-hVPS34 antibodies had no effect. The antibodies also had different effects on vesicular trafficking. Microinjection of inhibitory anti-hVPS34 antibodies, but not anti-p110alpha antibodies, blocked the transit of internalized PDGF receptors to a perinuclear compartment, and disrupted the localization of the early endosomal protein EEA1. Microinjection of anti-p110alpha antibodies, and to a lesser extent anti-hVPS34 antibodies, reduced the rate of transferrin recycling in CHO cells. Surprisingly, both antibodies inhibited insulin-stimulated DNA synthesis by 80%. Injection of cells with antisense oligonucleotides derived from the hVPS34 sequence also blocked insulin-stimulated DNA synthesis, whereas scrambled oligonucleotides had no effect. Interestingly, the requirement for p110alpha and hVPS34 occurred at different times during the G1-S transition. Our data suggest that different PI 3'-kinases play distinct regulatory roles in the cell, and document an unexpected role for hVPS34 during insulin-stimulated mitogenesis.

Actins↗
PubMed1998

Clinically favorable effects of raloxifene on bone mineral density and serum lipids: population assessment via bivariate analysis.

Introduction: Raloxifene is a nonsteroidal benzothiophene derivative that is classified as a selective estrogen receptor modulator (SERM). It has clinical promise because of its actions as an estrogen-agonist on bone and serum lipids and an estrogen-antagonist on the breast and uterus.Objectives: To determine the percentage of women who respond to raloxifene therapy with regard to bone mineral density (BMD) and serum low density lipoprotein cholesterol (LDL-C) concentration in a large population of healthy postmenopausal women.Methods: Pooled 24-month interim data from two multicenter, placebo-controlled, double-blind phase III studies were used in this analysis. The study population included 1145 healthy women, 45-60 years of age and 2-8 years postmenopausal, randomized to receive either placebo, raloxifene (RLX) 30 mg/day, RLX 60 mg/day, or RLX 150 mg/day. Changes in BMD, measured by dual x-ray absorptiometry, and serum LDL-C concentration, measured by enzymatic assay, were analyzed simultaneously by plotting the median percentage change (baseline to endpoint) in BMD of the lumbar spine and total hip on the y-axis against the corresponding median percentage change in serum LDL-C on the x-axis for each subject in the placebo group and each of the raloxifene groups. The data localized to one of four quadrants on the plot, the upper-left quadrant representing clinically favorable shifts (increased BMD and decreased LDL-C) and the lower-right quadrant representing clinically unfavorable shifts (decreased BMD and increased LDL-C). The bivariate mean, 50th and 95th percentile ellipses, and the percentage of patients improving in one, both, or neither of the measured parameters are displayed.Results: At the end of 24 months, the bivariate mean and the 50th and 95th percentile ellipses of the placebo group for lumbar spine BMD and LDL-C were shifted to the clinically unfavorable quadrant of the plot, reflecting a decrease in BMD and an increase in LDL-C. In contrast, the bivariate mean for all raloxifene groups had shifted to the clinically favorable quadrant of the plot, reflecting an increase in BMD and a decrease in LDL-C. There was a statistically significant difference (Hotelling-Lawley test, P <.001) in the bivariate mean for all doses of raloxifene compared to placebo. Only 19.1% of subjects in the placebo group exhibited improvement in both lumbar spine BMD and LDL-C, whereas 43.5%, 47.4%, and 49.8% of subjects in the RLX 30, RLX 60, and RLX 150 group, respectively, exhibited improvement in both of these variables. Furthermore, 35.9% of subjects in the placebo group exhibited no improvement in either lumbar spine BMD or LDL-C, whereas only 13.7%, 10.1%, and 11.6% of subjects in the RLX 30, RLX 60, and RLX 150 groups, respectively, exhibited no improvement in either of these variables. Similar results were obtained comparing total hip BMD and LDL-C.Conclusions: Compared with placebo, raloxifene has beneficial effects on BMD and LDL-C in a large sample of healthy postmenopausal women. Thus, insofar as these intermediate endpoints predict disease outcomes, long-term therapy with raloxifene may be beneficial in the prevention of osteoporosis and cardiovascular diseases.

Journal Article↗
PubMed1998

The efficacy of reducing agents or antioxidants in blocking the formation of dense cells and irreversibly sickled cells in vitro.

We show that N-acetylcysteine (NAC) has the ability to cause statistically significant diminishment in the in vitro formation of irreversibly sickled cells (ISCs) at concentrations greater than 250 micromol/L. Other antioxidants, approved for human use (cysteamine, succimer, dimercaprol), were not efficacious. NAC had the ability to cause statistically significant conversion of ISCs formed in vivo back to the biconcave shape. NAC was also shown to reduce the formation of dense cells and increase the available thiols in beta-actin. We showed that diminishing reduced glutathione (GSH), by treatment with 1-chloro-2,4-dinitrobenzene, resulted in increased dense cells. We conclude the NAC blocks dense cell formation and ISC formation by targeting channels involved in cellular dehydration and beta-actin, respectively. The efficacy of NAC is probably due to its combined antioxidant activity and ability to increase intracellular GSH.

Acetylcysteine↗
PubMed1998

Caspase inhibitor affords neuroprotection with delayed administration in a rat model of neonatal hypoxic-ischemic brain injury.

Programmed cell death (apoptosis) is a normal process in the developing nervous system. Recent data suggest that certain features seen in the process of programmed cell death may be favored in the developing versus the adult brain in response to different brain injuries. In a well characterized model of neonatal hypoxia-ischemia, we demonstrate marked but delayed cell death in which there is prominent DNA laddering, TUNEL-labeling, and nuclei with condensed chromatin. Caspase activation, which is required in many cases of apoptotic cell death, also followed a delayed time course after hypoxia-ischemia. Administration of boc-aspartyl(OMe)-fluoromethylketone, a pan-caspase inhibitor, was significantly neuroprotective when given by intracerebroventricular injection 3 h after cerebral hypoxia-ischemia. In addition, systemic injections of boc-aspartyl(OMe)-fluoromethylketone also given in a delayed fashion, resulted in significant neuroprotection. These findings suggest that caspase inhibitors may be able to provide benefit over a prolonged therapeutic window after hypoxic-ischemic events in the developing brain, a major contributor to static encephalopathy and cerebral palsy.

Amino Acid Chloromethyl Ketones↗