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Biomedical subjects

S Shah

Publications and source records attributed to S Shah.

At least 235 records · Page 13Linked to original sources
PubMed1997

["Tension-free technique" in open inguinal hernia repair. A prospective, randomized study of postoperative pain perception ("tension-free reconstruction" vs. Shouldice technique)].

A prospective randomized study was performed on 64 patients suffering from primary inguinal hernia. Two groups were formed, each consisting of 32 patients. The patients either underwent tension-free surgical treatment or Shouldice herniorraphy. The aim of the study was to determine if the tension-free operative technique on inguinal hernia patients reduces postoperative pain intensity by 2 days in comparison to the patients receiving Shouldice repair treatment. By using the VAS was shown that at no time was there any significant difference in the pain sensation levels between the two groups. The amount of pain tablets consumed among the patients was similar in each group. The number of complications in both groups was also comparable. During the postoperative follow-up of 6 days six patients in the tension-free surgical group and four patients in the Shouldice group developed uncomplicated hematomas on the 4th day, which were traced to the heparin medication. One patient from the Shouldice group suffered from temporary swelling of the scrotum. The advantage of open tension-free repair using extraperitoneally placed polypropylene mesh is that the technique is simple, size-adapted, and can be carried out easily and at any time under local anesthesia. With regard to the lower recurrence rate of hernia as published in the American literature, this can only be verified by randomized studies.

Adolescent↗
PubMed1997

Time-dependent effects of in vivo pertussis toxin on morphine analgesia and G-proteins in mice.

Previous studies have indicated a long-duration of effect of in vivo pertussis toxin (PTX) on morphine analgesia in the mouse. However, the time-course of potency changes in morphine analgesia as determined in dose-response studies and biochemical correlates of PTX treatment have not been reported to date. Therefore, in the present studies the effects of in vivo PTX on morphine analgesia ED50 and PTX-catalyzed incorporation of [32P]-ADP-ribose and synapsin content in mouse spinal cord were examined. Mice were injected IT & ICV with saline or PTX (total dose = 0.2 microg) and tested for systemic morphine analgesia (tail-flick) 1, 10, 16 & 40 days later. There was no significant decrease in morphine potency 1 day following PTX treatment, whereas PTX produced a significant decrease in morphine potency at 10, 16 & 40 days. Concurrent decreases in the incorporation of [32P]-ADP-ribose in spinal cord by PTX were observed on days 10, 16 & 40. No changes were observed in synapsin content which suggests that the effect was not nonspecific. This study indicates that in vivo PTX produces co-ordinate long-lasting effects in both functional (analgesia) and biochemical (Gi/o-proteins) assays.

Adenosine Diphosphate Ribose↗
PubMed1997

Mixed D2/5-HT2 antagonism differentially affects apomorphine- and amphetamine-induced stereotyped behavior.

Evidence supports the hypothesis that psychostimulant stereotypy is mediated through postsynaptic dopamine receptors. Given the recent findings of behavioral, neurochemical and electrophysiological studies showing 5-HT2 modulation of dopamine systems, a series of experiments were undertaken to assess the ability of D2 and 5-HT2 antagonists to reverse apomorphine and amphetamine stereotypy in the rat. Haloperidol reduced stereotyped behavior induced by d-amphetamine (50% reduction with 0.162 mg/kg) and apomorphine (50% reduction with 0.112 mg/kg) MDL 28,133A, a mixed D2/5-HT2 antagonist, also reduced stereotypy in the apomorphine group (50% reduction with 3.89 mg/kg) but was much less effective in antagonizing the effects of d-amphetamine (not even a 25% reduction with 9.0 mg/kg). MDL 100,907, a selective 5-HT2 antagonist, was ineffective at reducing stereotyped behavior induced by either stimulant. Thus, 5-HT2 modulation of dopaminergic activity was not demonstrated in the case of psychostimulant stereotypy. Furthermore, 5-HT2 antagonism did not induce stereotypy, as has been proposed in some models. These findings provide further support for the hypothesis that antipsychotic medications with high affinity for 5-HT2 receptors do not interfere with the regulation of the nigrostriatal dopaminergic system and, therefore, would be less likely to produce extrapyramidal side effects.

Amphetamine↗
PubMed1997

Results of excimer laser retreatment of residual myopia after previous photorefractive keratectomy.

BACKGROUND: Nine percent to 30% of all patients who undergo a single excimer laser photorefractive keratectomy (PRK) do not achieve an unaided visual acuity of 20/ 40 or better and may require optical correction to obtain adequate vision. METHODS: The authors performed a retrospective analysis of the records of 164 patients who had undergone retreatment with the excimer laser for residual myopia after a previous PRK. Mean follow-up was 35.5 +/- 15.2 weeks (range, 26-104 weeks). RESULTS: The mean spherical equivalent (MSE) before retreatment was -2.59 +/- 1.36 diopter (D) (range, -0.50 to -7.75 D). The final MSE after reablation was -0.52 +/- 1.36 D (range, 2.50 to -5.50). Of the 164 patients, 107 (65.2%) obtained a final refraction within 1.00 D of emmetropia and 111 (67.3%) achieved an unaided visual acuity of 20/40 or better. Only 10 patients (6.1%) lost more than one Snellen line of best-corrected visual acuity. The final MSE result for the subgroup of patients who had a pre-retreatment myopia of between -0.50 and -1.90 D (-0.31 +/- 1.09 D) was significantly closer to emmetropia than that of the subgroup with a residual myopia of -4.00 to -7.75 D (-1.62 +/- 1.94 D). CONCLUSIONS: Excimer laser retreatment may provide a relatively safe and predictable method of correcting residual myopia after an earlier PRK with a 25% extra correction recommended for residual myopia.

Adult↗
PubMed1997

Astigmatism induced by spherical photorefractive keratectomy corrections.

PURPOSE: The purpose of the study is to evaluate the induced astigmatism after spherical photorefractive keratectomy on the Summit Omnimed (Summit Instruments, Waltham, MA) and the Nidek EC-5000 (Nidek Co. Ltd, Aichi, Japan) excimer lasers. METHODS: A total of 4269 eyes of 3289 patients were treated with a 5-mm optical zone using the Summit Omnimed excimer laser and 1825 eyes of 1303 patients treated with the Nidek EC-5000 excimer laser. The final astigmatic refractive outcome was compared with the initial refraction by vector analysis (Alpin and Jaffe method). RESULTS: Subjective astigmatic refraction for the Summit laser reduced from a mean of -0.39 diopter (D) +/- standard deviation (SD) 0.33 D (range, 0 to -2.50 D) to -0.33 D +/- SD 0.41 D (range, 0 to -3.00 D). Surgically induced astigmatism (SIA) had a mean of 0.42 +/- SD 0.34 D (range, 0 to 2.89 D). Mean SIA increased with increasing preoperative astigmatism by 0.60 D SIA for every 1.00 D of preoperative cylinder. For the Nidek laser, subjective astigmatic refraction changed from a mean of -0.18 D +/- SD 0.21 D (range, 0 to -1.25 D) to -0.30 D +/- SD 0.33 D (range, 0 to -3.00 D). Surgically induced astigmatism had a mean of -0.32 D +/- SD 0.29 (range, 0 to 3.05 D). Mean SIA increased with increasing preoperative astigmatism by 0.47 D SIA for every 1.00 D of preoperative cylinder. CONCLUSIONS: The authors show that spherical photorefractive keratectomy corrections can induce significant astigmatic change, particularly if a large amount of preoperative astigmatism is present.

Astigmatism↗
PubMed1997

Reduction in intraocular pressure after excimer laser photorefractive keratectomy. Correlation with pretreatment myopia.

PURPOSE: The authors relate the observed reduction in intraocular pressure (IOP) after excimer laser treatment to the degree of myopia treated. BACKGROUND: Intraocular pressure, measured by both Goldmann applanation and noncontact tonometry, has been reported to decrease after excimer laser photorefractive keratectomy (PRK). However, IOP readings after excimer laser PRK might be inaccurate as a consequence of changes in both the thickness and curvature of the cornea. METHODS: Baseline IOP readings were measured by noncontact tonometry in each eye of a group of 1320 patients at the time of their initial consultation. These were compared to readings obtained before treatment of the second eye, which took place a minimum of 4 months later. The untreated eyes served as controls. The paired Student's t test was used for statistical analysis. RESULTS: After PRK, a decrease was observed in the IOP of treated eyes that was related to the degree of myopia treated. A significant difference was observed between treated and untreated eyes (P < 0.0000). CONCLUSIONS: The IOP measured after PRK for myopia may be reduced because of changes in corneal thickness (absence of Bowman's membrane and central thinning) and topography. This is of particular relevance when monitoring the IOP of those patients who are given steroid drops to prevent regression. It also may be of importance in the management of any future glaucoma.

Adult↗
PubMed1997

The effect of mu-opioid receptor antisense on morphine potency and antagonist-induced supersensitivity and receptor upregulation.

The present study examined the effect of in vivo antisense oligodeoxynucleotide treatment on naltrexone (NTX)-induced functional supersensitivity and mu-opioid receptor up-regulation in mice. On day 1 mice were implanted S.C. with a NTX or placebo pellet and injected I.T. and I.C.V. with dH2O or oligodeoxynucleotides. The oligodeoxynucleotides were designed so that they were either perfectly complementary to the first 18 bases of the coding region of mouse mu-opioid receptor mRNA, or had one (Mismatch-1) or four (Mismatch-4) mismatches. On days 3, 5, 7, and 9, mice were again injected I.T. and I.C.V. with dH2O or one of the oligodeoxynucleotides. After the final injections on day 9, placebo and NTX pellets were removed, and 24 h later mice were tested for morphine analgesia or sacrificed for saturation binding studies ([3H]DAMGO). Naltrexone increased the analgesic potency of morphine in dH2O treated mice by approximately 70%. In binding studies, NTX significantly increased density of brain (approximately 60%) and spinal cord (approximately 140%) mu-opioid receptors without affecting affinity. The mu-opioid antisense and the oligodeoxynucleotide with one mismatch (Mismatch-1) significantly reduced the potency of morphine by approximately twofold in placebo-treated mice. The oligodeoxynucleotide with four mismatches (Mismatch-4) did not significantly alter morphine potency. When placebo-treated mice were treated with either the antisense to the mouse mu-opioid receptor, Mismatch-4 or Mismatch-1 there were no significant changes in the density of mu-opioid receptors. Thus, mu-opioid antisense significantly reduced morphine potency without changing mu-opioid receptor density. When NTX and oligodeoxynucleotide treatments were combined, there was no change in NTX-induced supersensitivity and mu-opioid receptor upregulation. These data suggest that opioid antagonist-induced supersensitivity and upregulation of mu-opioid receptors does not involve changes in gene expression.

Animals↗
PubMed1997

Weight gain associated with adjuvant tamoxifen therapy in stage I and II breast cancer: fact or artifact?

There is a perception that tamoxifen causes weight gain in breast cancer patients. The purpose of this research study was to determine if weight gain is associated with tamoxifen therapy and to observe the impact of weight gain on recurrence and survival. Prognostic indicators, changes in weight, and disease status from diagnosis to the end of treatment were studied in 200 consecutive Stage I and II breast cancer patients, not receiving systemic chemotherapy, admitted from 1986 to the present, with observation periods ranging from 3-5 years. A mean weight gain of 1.2 Kgs was seen in all patients; however, weight gain was not significantly different for those receiving tamoxifen vs. those not receiving tamoxifen, (P = 0.66, CI 95% for the difference -1.8 Kgs to +1.2 Kgs). Weight gain during treatment with tamoxifen was not correlated with treatment duration or with recurrence or survival. Age at diagnosis was positively correlated to weight gain in all groups. Our data failed to show that tamoxifen is associated with weight gain. The moderate weight gain observed in this patient population is comparable to the general aging disease-free population and may no be treatment-related. These findings may help to alleviate some concerns of both physicians and patients when tamoxifen is the drug of choice for adjuvant therapy.

Adult↗
PubMed1997

Plant immunomodulators for termination of unwanted pregnancy and for contraception and reproductive health.

Neem (Azadirachta indica) seed and leaf extracts have spermicidal, anti-microbial, anti-fungal and anti-viral properties. They are also immunomodulators that induce primarily a TH1 type response. These properties are being exploited to develop two different useful methods of fertility control. Neem extracts given orally at early post-implantation stage terminate pregnancy in rodents and primates. Treatment has no residual permanent effect and fertility is regained in subsequent cycles. The mechanism by which the action occurs is not fully clear. A transient increase in CD4 and more significantly in CD8 cells is noticed in mesenteric lymph nodes and spleen. A rise in immunoreactive and bioactive TNF-alpha and IFN-gamma in draining lymph nodes, serum and foetal-placental tissue is observed. A polyherbal cream and pessary have been developed containing three active ingredients of plant origin. These have synergistic spermicidal properties on human sperm as determined by the Sander Cramer test. Their use before mating has high contraceptive efficacy in rabbits and baboons. Another interesting property is their inhibitory action on a wide spectrum of micro-organisms, including Candida albicans, C. tropicalis, Neisseria gonorrhoeae, the multidrug-resistant Staphylococcus aureus and urinary tract Escherichia coli, Herpes simplex-2 and HIV-1. Phase I clinical trials have been completed in India, Egypt and the Dominican Republic, and indicate the safety of the formulation, its acceptability and beneficial action invaginosis due to infections.

Abortion, Induced↗
PubMed1997

Subtyping of Listeria monocytogenes on the basis of plasmid profiles and arsenic and cadmium susceptibility.

The susceptibilities to arsenic and cadmium together with the detection of plasmid DNA were evaluated for use as epidemiological markers for the subtyping of Listeria monocytogenes. Plasmid DNA was detected in 34% of 322 apparently unrelated isolates of L. monocytogenes. The resistance to cadmium and arsenic differentiated 565 apparently unrelated cultures into four groups, the smallest being 5% of cultures resistant to both agents, and the largest (53%) being sensitive to cadmium and resistant to arsenic. The resistance patterns to these agents and the presence of plasmid DNA varied markedly between the serotypes of the cultures. The detection of plasmid DNA was strongly associated with cadmium resistance in serogroup 1/2 cultures, but not within those of serogroup 4. Arsenic resistance was not associated with plasmid DNA. All methods were sufficiently stable to be useful for epidemiology investigations. The techniques described here offer simple methods which can be easily utilized in laboratories without a specialized expertise for this bacterium.

Arsenites↗
PubMed1997

In-vitro microbiological assessment of a new penem, Men 10700.

The in-vitro antibacterial activity of Men 10700, a novel penem, has been compared with that of ritipenem, ciprofloxacin, amikacin, cefotaxime and co-amoxiclav against 539 strains taken from 17 genera. Men 10700 was most active against staphylococci and streptococci (MIC90 < 0.5 mg/L), slightly less active against Escherichia coli, Klebsiella pneumoniae, Enterobacter spp., Citrobacter spp., Moraxella catarrhalis and peptostreptococci (MIC90 0.5-2 mg/L), moderately active against Enterococcus faecalis, members of the tribe Proteae, Serratia marcescens, Acinetobacter spp., clostridia and Bacteroides spp. (MIC90 4-16 mg/L), and inactive against Pseudomonas aeruginosa, Stenotrophomonas maltophilia and Enterococcus faecium. Its antibacterial spectrum is thus slightly less broad than that of imipenem, but it compares favourably with an oral third-generation cephalosporin. Men 10700 was more active than ritipenem against many species, especially Enterobacter spp. and Citrobacter spp.

Anti-Bacterial Agents↗
PubMed1997

Activity of quinupristin/dalfopristin against Staphylococcus epidermidis in biofilms: a comparison with ciprofloxacin.

Bactericidal effects of quinupristin/dalfopristin and ciprofloxacin have been studied against six strains of Staphylococcus epidermidis, with varying erythromycin resistance phenotypes and varying abilities to form slime and adhere, growing as biofilms. Ciprofloxacin and quinupristin/dalfopristin killed (2-3 log10 cfu/mL) planktonic and sessile cells slowly, but progressively, over the course of 48 h. Rates of killing by quinupristin/dalfopristin were independent of concentration over the range 5-30 mg/L, and were somewhat slower than those seen with ciprofloxacin. These findings suggest that quinupristin/dalfopristin may be useful in the treatment of line-associated infections.

Anti-Bacterial Agents↗
PubMed1997

The structure of the human multiple exostoses 2 gene and characterization of homologs in mouse and Caenorhabditis elegans.

Hereditary multiple exostoses (EXT) is an autosomal dominant disorder characterized by multiple cartilage-capped outgrowths from the epiphyses of long bones. In some cases, these osteochondromas progress to malignant chondrosarcomas. Alterations in at least three genes (EXT1, EXT2, and EXT3) can cause this disorder. Two of these have been isolated (EXT1 and EXT2) and encode related members of a putative tumor suppressor family. We report here the genomic structure of the human EXT2 gene consisting of 14 exons (plus 2 alternative exons) covering an estimated 108 kb of chromosome 11p11-13. We have derived the DNA sequences at all exon/intron boundaries throughout this gene-information that is important for the detailed study of mutations in EXT2. We have also characterized the mouse EXT2 cDNA and have mapped the mouse locus to chromosome 2 between D2Mit15 and Pax6. This mouse homolog should enable transgenic knockout experiments to be initiated to further elucidate gene function. Interestingly, sequence comparisons reveal that the human and mouse EXT genes have at least two homologs in the invertebrate Caenorhabditis elegans, indicating that they do not function exclusively as regulators of bone growth. This observation opens the way for a functional analysis of these genes in nematodes and other lower organisms.

Amino Acid Sequence↗
PubMed1997

Overexpression of the FAD3 desaturase gene in a mutant of Arabidopsis.

A mutant of Arabidopsis contained increased levels of 18:3 fatty acids and correspondingly decreased levels of 18:2. The fatty acid phenotype was strongly expressed in root and seed tissues and this observation, together with other data, suggested that the mutation leads to increased activity of the endoplasmic reticulum 18:2 desaturase encoded by the FAD3 gene. Gel-blot analysis of RNA from wild-type and mutant plants established that FAD3 transcript levels were increased 80% in the mutant relative to the wild type. Genetic analysis demonstrated a linkage between the new mutation and the fad3 locus. Linkage of the mutation to fad3 raises the possibility that the lesion is an alteration to the promoter or another regulatory region of the FAD3 gene, which results in increased transcription.

Arabidopsis↗
PubMed1997

Induced termination of pregnancy by purified extracts of Azadirachta Indica (Neem): mechanisms involved.

PROBLEM: To develop a self-administered, orally delivered method for abrogation of early pregnancy. METHOD: Use of purified Neem extracts containing immunomodulators stimulating Th1 cells and macrophages; test animals, rats, baboons, and monkeys, onset of pregnancy confirmed by surgery and counting of implants on day 7 in rats and by chorionic gonadotropin (CG) and progesterone assays in primates; termination defined by complete resorption on day 15 in rats and by bleeding and decline of CG and progesterone in baboons. RESULTS: Pregnancy was terminated successfully in both rodents and primates with no significant side effects. Fertility was regained in both species after one or two irregular cycles. Progeny born had normal developmental landmarks and mothered normal litters in the course of time. The active principle in Neem has been partially fractionated by activity-guided purification. A cascade of events are involved in abrogation of pregnancy. In primates, a decrease in progesterone is an early event. A transient increase in CD4 and CD8 cells is noted in spleen at 96 hr and in mostly CD8 cells in mesenteric lymph nodes. Treatment causes an elevation of both immunoreactive and bioactive TNF-alpha and gamma-interferon in serum, mesenteric lymph nodes, and foetoplacental tissue. CONCLUSION: Immunomodulators of plant origin are potentially usable for termination of unwanted pregnancy

Abortifacient Agents, Nonsteroidal↗
PubMed1997

Quinolone resistance locus nfxD of Escherichia coli is a mutant allele of the parE gene encoding a subunit of topoisomerase IV.

The locus nfxD, which contributes to high-level quinolone resistance in Escherichia coli KF111b (gyrAr nfxB nfxD), is only expressed in the presence of a gyrA mutation, and maps to the region of the parC and parE genes, was outcrossed into strain KF130, creating strain DH161 (gyrAr nfxD). DNA sequence analysis of DH161 revealed no changes in the topoisomerase IV parC quinolone resistance-determining region but did identify a single T-to-A mutation in parE at codon 445, leading to a change from Leu to His. Full-length cloned parE+ partially complemented the resistance phenotype in KF111b and DH161, but did not complement the resistance phenotype in strain KF130 (gyrAr). No complementation was seen with cloned, truncated parE+. To confirm these findings, gyrAr was first outcrossed from KF130 into E. coli W3110parE10 [parE temperature sensitive(Ts)] and KL16. The transduced strains KL16 and W3110parE10 were subsequently transformed with plasmids containing cloned parE from DH161 or KL16. Cloned parE from DH161 increased norfloxacin resistance in the parE(Ts) background twofold at 30 degrees C and fourfold at 42 degrees C compared to those for cloned parE from KL16. The same experiment with a non-Ts background revealed a twofold increase in the norfloxacin MIC at both 30 and 42 degrees C. These data identify the nfxD conditional resistance locus as a mutant allele of parE. This report is the first of a quinolone-resistant parE mutant and confirms the role of topoisomerase IV as a secondary target of norfloxacin in E. coli.

Alleles↗
PubMed1997

Creatine kinase subform analysis in hemodialysis patients without acute coronary syndromes.

The finding of elevated levels of creatine kinase (CK) and its myocardial isoenzyme (CK MB) in the blood of patients with acute chest pain syndromes is a key factor in making the diagnosis of acute myocardial infarction. With the widespread use of thrombolytic therapy and emergency angioplasty, the ability to make a rapid and accurate diagnosis of myocardial infarction is critical. A new rapid method for analysis of the subforms of the MB isoenzyme has been shown to be sensitive and specific for the diagnosis of myocardial infarction in the general population. Because of its rapidity it has been replacing standard analyses of total CK and CK MB in some centers in guiding the initial therapy of patients with chest pain. Levels of CK MB can be abnormally elevated in hemodialysis patients even in the absence of acute myocardial necrosis. This study was undertaken in order to determine if subform analysis of the MB isoenzyme could similarly be abnormal in hemodialysis patients without acute coronary syndromes. CK MB subforms were analyzed in 52 patients without any recent cardiac symptoms who came into the dialysis unit for a routine hemodialysis treatment. We then applied the same criteria for the diagnosis of an acute myocardial infarction as would be used clinically. In this population, the subform analysis was surprisingly consistent with myocardial infarction in approximately 29% of the patients. Thus, subform analysis appears likely to result in an erroneous diagnosis of acute myocardial infarction in patients on hemodialysis.

Acute Disease↗