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Biomedical subjects

S Green

Publications and source records attributed to S Green.

At least 163 records · Page 9Linked to original sources
PubMed1997

'Curing' empty follicle syndrome.

We report a novel method of rescuing empty follicle syndrome (EFS) and provide evidence that it is a drug-related problem rather than a clinical dysfunction. In a preliminary study we established that in EFS the serum beta-human chorionic gonadotrophin (beta-HCG) concentrations 36 h after HCG administration never exceeded 10 mIU/ ml. beta-HCG concentrations were thus used to confirm EFS when oocytes were not retrieved from one ovary after controlled ovarian hyperstimulation. The procedure was suspended leaving intact all follicles in the second, ovary. After confirmation of EFS, a second HCG from a different batch was administered and 36 h later mature oocytes were retrieved from the intact ovary, suggesting a fault with the HCG previously administered. Three patients have been treated in this way. In the first case, four out of five mature eggs were fertilized after intracytoplasmic sperm injection (ICSI) resulting in the transfer of three top grade (grade 1) embryos. In the second case all seven mature oocytes fertilized after in-vitro fertilization (IVF) and three grade 1 embryos were transferred resulting in a twin pregnancy, now delivered. In the third case, five out of nine oocytes were fertilized after ICSI and one out of the three treated with high insemination concentration IVF fertilized, resulting in the transfer of three ICSI embryos.

Chorionic Gonadotropin↗
PubMed1997

Increased polymorphonuclear granulocytes in seminal plasma in relation to sperm morphology.

Much controversy surrounds the clinical significance of an increased concentration of white blood cells (WBC) in the male ejaculate. The World Health Organization's classification of leukocytospermia is a concentration > 1 x 10(6) WBC/ml. The aim of this study was to assess the association of varying concentrations of leukocytes to sperm morphology evaluated by strict criteria. Semen samples were collected from a total of 79 patients. Round cells on the initial semen analysis were stained for identification of polymorphonuclear granulocytes (PMN) as the largest group (50-60%) of white blood cells using the Endtz Method commercially produced as Leucoscreen. Diff Quick Staining Kit was used for sperm morphology assessment and 200 spermatozoa were assessed per slide. Data were evaluated using two cut-off criteria, at 0.5 x 10(6) WBC/ml and 1 x 10(6) WBC/ml. Mann-Whitney U-values at both < and > 0.5 x 10(6)/ml PMN (P < 0.001) and at < and > 1.0 x 10(6)/ml PMN (P < 0.015) showed differences between percentage normal forms. Spearman's rank correlation coefficient for PMN concentration showed a negative correlation (P < 0.01) with percentage normal sperm morphology and positive correlation for midpiece abnormalities (P < 0.04). These data support the hypothesis that PMN have a role in the increase of abnormal spermatozoa, particularly those with midpiece abnormalities, by as yet unknown mechanisms.

Blood Cell Count↗
PubMed1997

Human fertilization with round and elongated spermatids.

Human spermatids from ejaculate and testicular tissue have been utilized for evaluating human fertilization by intracytoplasmic sperm injection (ICSI) and, where possible, compared with spermatozoa utilizing sibling oocytes. Round and elongated spermatids obtained from ejaculates were either prepared through Percoll gradients or isolated and washed individually using subzonal insemination needles (SUZI; 10-14 microm internal diameter). Seminiferous tubules obtained after biopsy were placed into HEPES-buffered Earle's medium and dissected using 21-gauge needles. Spermatogenic cells and spermatozoa were isolated and washed individually using SUZI needles. Spermatozoa were subsequently injected into the ooplasm using 5 microm (internal diameter) ICSI needles, whereas 8-9 microm (internal diameter) needles were used for spermatid injection. Only metaphase II oocytes (n = 207) were injected: 64 with round spermatids, 92 with elongated spermatids and 51 with spermatozoa; the fertilization rate was 30, 24 and 67% respectively. There was a significant (P < 0.001) increase in the fertilization rate using spermatozoa compared with spermatids. The fertilization rate was not different between round and elongated spermatids, although the fertilization rates for round and elongated spermatids in the ejaculate were 33 and 18% respectively, compared with 22 and 38% respectively when testicular spermatids were utilized. In three patients sibling oocytes were used to compare round and elongated spermatids found in the ejaculate with spermatozoa extracted from seminiferous tubules. The fertilization rate was 24% for spermatids and 79% for testicular spermatozoa. This result suggests that, should only spermatids be available in the ejaculate, a testicular biopsy in the hope of obtaining testicular spermatozoa would be worth while.

Cell Size↗
PubMed1997

Ramp and constant power trials produce equivalent critical power estimates.

The standard critical power test protocol on the cycle ergometer prescribes a series of trials to exhaustion, each at a different but constant power setting. Recently the protocol has been modified and applied to a series of trials to exhaustion each at a different ramp incremental rate. This study was undertaken to compare critical power and anaerobic work capacity estimates in the same group of subjects when derived from the two protocols. Ten male subjects of mixed athletic ability cycled to exhaustion on eight occasions in randomized order over a 3-wk period. Four trials were performed at differing constant power settings and four trials on differing ramp incremental rates. Both critical power and anaerobic work capacity were estimated for each subject by curve fitting of the ramp model and of three versions of the constant power model. After adjusting for inter-subject variability, no significant differences were detected between critical power estimates or between anaerobic work capacity estimates from any model formulation or from the two protocols. It is concluded that both the ramp and constant power protocols produce equivalent estimates for critical power and anaerobic work capacity.

Adult↗
PubMed1997

Use of ciprofloxacin in developing countries.

BACKGROUND: The demographic and subsequent economic pressures in developing nations have contributed to the increasing levels of antibiotic resistance among both commensal flora and pathogenic bacteria. As empirical options are diminishing daily, the role of ciprofloxacin in pediatric infections is becoming increasingly significant. OBJECTIVE: The levels of resistance among various enteric pathogens are described, and the efficacy and safety of ciprofloxacin in treating infections such as shigellosis, cholera and Escherichia coli gastroenteritis are discussed. The findings of a large study of invasive salmonellosis in children in rural Africa are briefly presented, including the role of ciprofloxacin in multiresistant invasive disease. In addition the role of ciprofloxacin as a chemoprophylactic agent in the control of meningococcal disease is discussed. RESULTS: The efficacy and safety of ciprofloxacin in children were found to be similar to those observed in adults for gastrointestinal infectious diseases. Overall the data presented confirm that ciprofloxacin is a safe and efficacious agent for use in children in the developing world. CONCLUSION: Ciprofloxacin has been shown to be safe and efficacious in children in developing countries. Subsequently a priority for both the pharmaceutical industry and regulatory authorities in developing nations is to prevent fluoroquinolone misuse and development of antibiotic resistance.

Anti-Infective Agents↗
PubMed1997

Lymphogranuloma venereum: biopsy, serology, and molecular biology.

A 21 year old woman presented with painful groin lymphadenopathy and malaise. Lymph node biopsy, to exclude atypical infection and malignancy, suggested the diagnosis of lymphogranuloma venereum. This diagnosis was confirmed by serology and polymerase chain reaction, with the patient subsequently admitting to a casual sexual contact within the United Kingdom. Alternative methods of investigation of this disease are discussed.

Adult↗
PubMed1997

bcl-2, p53, and response to tamoxifen in estrogen receptor-positive metastatic breast cancer: a Southwest Oncology Group study.

PURPOSE: To test the hypothesis that high bcl-2 expression and accumulation of p53 protein, both of which should inhibit apoptosis, are associated with a poorer tamoxifen response and a more aggressive clinical course in estrogen receptor (ER)-positive metastatic breast cancer. METHODS: A total of 205 paraffin-embedded tumor blocks were evaluated for nuclear p53 (a marker of p53 inactivation) and cytoplasmic bcl-2 by immunohistochemistry (IHC). All patients received tamoxifen as initial therapy for metastatic disease. The study began in 1982 and follow-up duration of the 24 patients last known alive is 8 years. RESULTS: Response to tamoxifen and time to treatment failure (TTF) were not significantly associated with p53 status, although patients with higher p53 had a worse survival (P = .008; median, 36 v 20 months). Higher bcl-2 expression was associated with higher levels of ER (P = .02), better response to tamoxifen (62% v 49%; P = .07), longer TTF (median, 9 v 5 months; P = .002), and better survival (median, 40 months v 25 months; P = .009). In multivariate analyses, including ER, progesterone receptor (PgR), and p53, high bcl-2 remained significantly associated with a longer TTF (P = .007) and survival (P = .07). p53 status was a significant factor for shorter survival (P = .05), but not for TTF (P = .61). CONCLUSION: p53 status, as determined by IHC is not significantly associated with response to tamoxifen, although tumors with altered p53 protein are inherently more aggressive. Contrary to expectation, high bcl-2 identifies a relatively indolent phenotype of ER-positive metastatic breast cancer, in which patients experience a better clinical response to tamoxifen and a longer survival.

Adult↗
PubMed1997

Rapid diagnosis of dengue viremia by reverse transcriptase-polymerase chain reaction using 3'-noncoding region universal primers.

A reverse transcriptase-polymerase chain reaction (RT-PCR) method was developed as a rapid diagnostic test of dengue viremia. To detect dengue viruses in serum or plasma specimens, a pair of universal primers was designed for use in the RT-PCR. Using these primers, the 3'-noncoding region of dengue virus types 1, 2, 3, and 4 could be amplified, but not those of other flaviviruses, such as West Nile virus, Japanese encephalitis virus, and yellow fever virus, or the alphavirus Sindbis virus. The sensitivity of the RT-PCR assay was similar to that of a quantitative fluorescent focus assay of dengue viruses in cell culture. Combining a silica method for RNA isolation and RT-PCR dengue virus could be detected in a 6-hr assay. In a preliminary study using this method, we detected dengue virus in 38 of 39 plasma specimens from which dengue virus had been isolated by mosquito inoculation. We then applied this method for detecting dengue viremia to 117 plasma samples from 62 children with acute febrile illnesses in a dengue-endemic area. We detected dengue viremia in 19 of 20 samples obtained on the day of presentation, which had been confirmed as acute dengue infection by mosquito inoculation and antibody responses. The overall sensitivity of this method was 91.4% (32 of 35; 95% confidence interval [CI] = 82.2-100%). The results from testing plasma samples from febrile nondengue patients showed a specificity of 95.4% (42 of 44; 95% CI = 89.3-100%).

Acute Disease↗
PubMed1997

Reflection of an experience!

Reflection has become an everyday word in the nursing press and literature, but what does it mean exactly to us as nurse practitioners, and how can we actually use it to good effect in our everyday working practice? Much of the literature available on reflection is both complex and abstract. The aims of this article are to give an insight into the topic through reviewing the literature and then presenting a personal example of 'reflection of an experience'.

Humans↗
PubMed1996

Bcl-2 regulates activation of apoptotic proteases in a cell-free system.

BACKGROUND: Apoptosis plays an important role in the normal development and homeostasis of metazoans. Aberrations in this process have been implicated in several major human diseases, but its molecular mechanism is poorly understood. In animals as diverse as humans and nematodes, the Bcl-2 oncoprotein prevents or delays apoptosis, whereas proteases of the interleukin-1beta-converting enzyme (ICE) family are required, suggesting that they are components of a conserved mechanism controlling the onset of apoptosis. RESULTS: A cell-free system produced from Xenopus laevis eggs reproduces nuclear events characteristic of apoptosis after a lag phase. We have used this system to define the temporal sequence of biochemical events and to examine the relationship between Bcl-2 and apoptotic proteases. Bcl-2 prevents apoptotic chromatin condensation and DNA cleavage, but only when added prior to the activation of a protease which has characteristics similar to the Ced-3 sub-family of ICE-like proteases and which cleaves poly(ADP-ribose) polymerase (PARP). Bcl-2 attenuates activation of this protease, an effect that does not require de novo protein synthesis or the presence of intact nuclei. The Ced-3-related protease CPP-32 is cleaved during the late stages of apoptosis in this system and after PARP cleavage. Generation of CPP-32-cleaving activity is inhibited by Bcl-2. CONCLUSIONS: These experiments provide direct biochemical evidence that Bcl-2 protects against apoptosis, at least in part, by regulating the activation of a series of apoptotic proteases that cleave PARP and other substrates. This cell-free system provides a useful biochemical model for analyzing the molecular mechanism controlling the activation of these proteases.

Animals↗
PubMed1996

Evaluation of blood pressure response to the combination of enalapril (single dose) and diltiazem ER (four different doses) in systemic hypertension.

Angiotensin-converting enzyme inhibitors and calcium antagonists are 2 classes of antihypertensive agents frequently used either as monotherapy or in combination. A 6-week, multicenter, randomized, double-blind, placebo-controlled trial was conducted in essential hypertensive patients (diastolic blood pressures [BP] when seated, 95-115 mm Hg) to evaluate the efficacy, dose response, and safety profiles of enalapril combined with a new once-daily formulation of diltiazem. BP and heart rate were measured at 5 (peak) and 24 (trough) hours after dose to assess the efficacy and pharmacodynamic profile of the combination given once daily. There were 336 patients randomly assigned to either enalapril 5 mg plus 1 of 4 dose levels of diltiazem ER (60, 120, 180, or 240 mg), enalapril 5 mg alone, or placebo. Each combination dose level produced statistically significant reductions (p <0.05) in trough diastolic BP when seated, compared with placebo (-6.8, -8.3, -10.1, and -10.3 mm Hg for the diltiazem ER doses of 60, 120, 180, and 240 mg, respectively). The 3 highest combination dose levels resulted in statistically significant (p <0.05) decreases in trough diastolic BP when seated, compared with placebo. There was a significant (p <0.001) linear dose-response relation. A trough-to-peak ratio > or = 0.5 was shown for the 3 highest combination doses. Drug-related adverse events were seen in 8.9% to 19% of the combination patients, 14.3% of the enalapril patients, and 8.6% of the placebo patients. The frequency and type of adverse events were those currently noted with each drug studied when used as monotherapy.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1996

Cloning and expression in Xenopus oocytes of a mouse homologue of the human acylcoenzyme A: cholesterol acyltransferase and its potential role in metabolism of oxidized LDL.

We used a Xenopus oocyte expression system to screen a mouse macrophage cDNA library for receptors for oxidized LDL (OxLDL). Injection of unfractionated mouse macrophage mRNA induced OxLDL binding activity on oocytes. An excess of acetylated LDL (AcLDL) inhibited the binding of OxLDL by only 30%, indicating the expression of OxLDL receptors distinct from the scavenger receptor (SRA). The library was screened and analyzed by competition binding using [125I]OxLDL and AcLDL, to avoid cloning of SRA. One of the purified clones encoded a peptide with 85% identity with human acyl-coenzyme A:cholesterol acyltransferase (ACAT). Injection of ACAT mRNA into oocytes induced specific binding of OxLDL. ACAT is expressed in mouse macrophages as a approximately 3.6 kB transcript and the expression is upregulated in human THP-1 cells treated with PMA.

Amino Acid Sequence↗
PubMed1996

The Y-intercept of the maximal work-duration regression and field tests of anaerobic capacity in cyclists.

The purpose of the present study was to provide initial data upon which field tests of anaerobic capacity for cyclists might be developed, by examining the relationships between the y-intercept of the maximal work-duration regression (Y-int) and cycle performance variables in fifteen well-trained male cyclists (mass = 73.3 +/- 8.6 kg; VO2peak = 4.93 +/- 0.70 l.min-1). The Y-int was determined from three maximal supra-VO2peak cycle bouts varying in duration from 195 to 369 s. Each cyclist performed two performance tests: 1) an all-out cycle sprint over 1000 m (AOS) during which the accumulated time over intervals of 125 m (e.g., AOS125, AOS250, etc. was recorded; 2) a 2-by-2000 m ride from which an "anaerobic distance" (Anl) was determined as the product of anaerobic speed (i.e. average speed during a second, maximal 2000 m time-trial minus the average speed during a 20 km time-trial) and time taken to complete the maximal 2000 m ride. The frontal area (FA) of each cyclist and common values for air density, work efficiency and the drag coefficient were used to estimate the energy equivalent of Anl. The Y-int was 20.0 +/- 9.4 kJ or 278 +/- 128 J.kg-1. The Y-int (J.FA-1) was correlated (p < or = 0.05) with AOS250 (r = -0.50), AOS375 (r = -0.53) and AOS625 (r = -0.50) which were 21.5 +/- 1.1 s, 30.1 +/- 1.3 s and 47.5 +/- 1.9 s long, respectively. The Y-int (kJ) was also correlated with AOS375 (r = -0.51), but Y-int (kJ) was not correlated with a performance variable lasting longer than approximately 30 s. The energy equivalent of Anl (91.5 +/- 26.0 kJ) was similar to the energy equivalent for Y-int (90.9 +/- 43 kJ), although these two variables were not significantly correlated. However, given the potential sources of variance in determining both of these variables, their quantitative similarity provides limited evidence supporting the use of Anl to estimate anaerobic capacity. The results also support the use of an all-out sprint performance lasting between 20-30 s to best reflect anaerobic work capacity in cyclists.

Adult↗
PubMed1996

A primary health care service for Glasgow street sex workers--6 years experience of the "drop-in centre', 1989-1994.

In Glasgow, a health and social care centre opened in 1988 principally to facilitate HIV prevention among street prostitutes, most of whom are injecting drug users. During 1992 to 1994, 551 women made 17,554 visits to the medical room which is functional 5 nights per week. The mean age of the sex workers was 26 years (range 15 to 62) and 89% injected drugs. Fifty-five per cent of the attendances were for needle/syringe exchange only whilst the remainder involved other health care provision. Common presenting problems included abscesses, burns and venous thromboses, reflecting the high proportion of sex workers who injected drugs. Most women always used condoms for penetrative commercial sex and symptomatic sexually transmitted disease was seen infrequently. In addition to the provision of injecting equipment and condoms, other key prevention activities included Hepatitis B vaccination and cervical screening. The prevalence of HIV infection amongst the women remains under 5% and most seropositives were known to be infected before the Centre opened. This initiative shows that if multidisciplinary health and social services are provided to street sex workers at a time and place convenient to their work, the benefits are considerable.

Adolescent↗
PubMed1996

The hippocampus: a "working memory" structure? The effect of hippocampal sclerosis on working memory.

Patients with medically intractable epilepsy and either hippocampal sclerosis or frontal lobe lesions were compared with healthy controls, to investigate a possible neuroanatomical correlate of a component of working memory: the central executive. Patients were tested on a short-term memory task which comprised visuo-spatial and verbal components, in single and concurrent trials. Differences were found between the patient groups for dual-task capacity, despite being equated on single-task trials. Patients with frontal lobe damage were the most affected by the demands of attention division. The results of this study do not support the thesis of a hippocampal role in the working memory component examined, but point to a frontal lobe focus for this janusian cognitive function. An unexpected finding of an increment in performance over the trials of visuo-spatial assessment, in patients with hippocampal sclerosis, is presented.

Analysis of Variance↗
PubMed1996

Effects of gamma-aminobutyric acid on human sperm motility and hyperactivation.

This study was undertaken to evaluate the effects of gamma-aminobutyric acid (GABA) and GABAergic agonists and antagonists on sperm kinematic parameters and hyperactivation, evaluated by a computer-assisted semen analysis (CASA) system, and intracellular cAMP content in 22 normozoospermic semen samples. Because of the possible interaction of progesterone with the GABAA receptor, we also evaluated the effects of progesterone on these parameters. GABA increased beat cross frequency, curvilinear velocity (VCL), the percentage of spermatozoa moving with an average path velocity > 10 microns/s (active) and hyperactivation, and decreased linearity and straightness. Bicuculline, a GABAA receptor antagonist, antagonized the effects of GABA on all these parameters except the percentage of active spermatozoa. Muscimol, a GABAA receptor agonist, increased VCL, the percentage of active spermatozoa, and hyperactivation by about the same extent as GABA, suggesting the involvement of the GABAA receptor. However, the GABAB receptor also seems to mediate some of the effects of GABA, because baclofen, a selective agonist for this receptor, increased significantly the percentage of active spermatozoa and hyperactivation. The effect of baclofen on this latter parameter was, however, less pronounced than that obtained with GABA or muscimol. Progesterone had the same effects as GABA on sperm kinematic parameters and hyperactivation and the simultaneous presence of both compounds was not more effective than each single one. GABA and progesterone did not have any effect on intracellular cAMP content. In conclusion, GABA modulated sperm kinematic parameters and increased hyperactivation. These effects have the same magnitude of those produced by progesterone and seem to be mediated mainly by the GABAA receptor. We speculate that GABA may be a physiological regulator of sperm function.

Baclofen↗
PubMed1996

Anaerobic ATP production and accumulated O2 deficit in cyclists.

Anaerobic ATP production in skeletal muscle and the accumulated oxygen deficit (O2D) incurred during an exhaustive cycle bout (duration = 173 +/- 24 s; intensity = 112 +/- 3% VO2peak), were determined in 10 male cyclists (mean +/- SD: VO2peak = 69.8 +/- 4.2 ml.kg-1.min-1). Anaerobic ATP production (mmol.kg-1 d.w.) was determined from changes in lactate, phosphocreatine, ATP, and ADP in vastus lateralis. Muscle buffer value and the activities of glycogen phosphorylase (PHOS), phosphofructokinase and citrate synthase (CS) were also determined. The anaerobic ATP production determined from measured muscle metabolites was 202.7 +/- 46.9 mmol.kg-1 d.w. and was correlated (P < or = 0.05) with muscle buffer value (r = 0.81), PHOS (r = 0.69) and the ratio of PHOS to CS activity (r = 0.77). The O2D was 55.2 +/- 10.3 ml O2 Eq.kg-1, but was not correlated (P > 0.05) with anaerobic ATP production (r = -0.38), buffer value (r = -0.50) or PHOS (r = -0.39). These latter findings could be explained by error in measuring the O2D and/or muscle anaerobic ATP production in well-trained cyclists.

Adenosine Triphosphate↗