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Biomedical subjects

R Edwards

Publications and source records attributed to R Edwards.

At least 199 records · Page 11Linked to original sources
PubMed1995

Changes in protein methylation associated with the elicitation response in cell cultures of alfalfa (Medicago sativa L.).

The methylation of endogenous proteins increased in alfalfa cell suspension cultures following treatment with a fungal elicitor. Carboxyl methylation, a post-translational modification associated with controlling the localisation and longevity of proteins, was the dominant form of protein methylation in both elicited and unelicited cells. Protein methylation was restricted to a limited number of peptides prior to elicitor treatment but as elicitation progressed the number of endogenous substrates increased. Increases resulted from a combination of an elicitor-dependent increase in the activity of a protein carboxyl methyltransferase and the accumulation of preferred endogenous substrates in the latter stages of elicitation.

Cells, Cultured↗
PubMed1995

Epidemiology and practice of emergency medicine in a developing country.

STUDY OBJECTIVE: To analyze the emergency medicine system in a developing country and identify areas of need and potential collaboration. DESIGN: Convenience sample surveys of all emergency visits over a 2-week period, hospital admission and health department statistics, and interviews with government officials, health providers, and EMS managers. SETTING: Port of Spain General Hospital, Trinidad and Tobago. RESULTS: The ED has more than 100,000 visits per year. No records are kept. No physician in this study had emergency medicine training; only one had completed any residency. The survey included 3,710 patients: 40.5% were admitted, and .3% died. Injuries accounted for 41.6% of all visits, asthma 7.8%. The mean time elapsed before a patient was seen was .5 hour; mean time to discharge, 1.9 hours. In only 9% of patients were laboratory tests performed. Prehospital providers had limited equipment and training. CONCLUSION: The ED and prehospital systems provide high-volume and often high-acuteness care. Barriers to improved care include limited specialized training and lack of medical records.

Adolescent↗
PubMed1995

A comparison of the efficacy and tolerability of moclobemide given as a single daily dose or in three divided doses per day for the treatment of patients with a major depressive episode (DSM-III-R)

This was a prospective, double-blind, randomized, multicenter trial comparing moclobemide once daily (OD) with three times daily (TDS) dosing. The duration of the study was 6 weeks with the initial dose of moclobemide being 450 mg/day (either 450 mg in the morning or 150 mg three times daily). Placebo tablets were used to ensure that the study was double blind. After 2 weeks, the dose could be increased to 600 mg/day if tolerability was acceptable and efficacy was judged insufficient by the investigator. Patients were assessed at baseline and at days 3, 7, 14, 21, 28, and 42. Efficacy was primarily judged on the Hamilton Rating Scale for Depression (HAM-D) (17item). Patients had to score at least 17 to enter the study. Safety and tolerability were judged on reported adverse events, safety parameters, premature withdrawals, and a physicians' global tolerability rating. There were also three secondary efficacy parameters--the Hamilton Rating Scale for Anxiety, Visual Analogue Scales for pain and irritability, and physicians' Clinical Global Impression (CGI). A total of 130 evaluable patients were required to detect a difference of more than 20% (alpha = 0.05 and beta = 0.8) between groups. A total of 189 patients entered the study, and the standard analysis comprised 145 patients. The efficacies between the two dosing regimens as determined by the HAM-D score and from the CGI were found not to differ significantly. For the standard analysis population, there was a reduction in mean HAM-D of 73.8 and 72.9% for the OD and TDS groups, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Benzodiazepines attenuate the pituitary-adrenal responses to corticotrophin-releasing hormone in healthy volunteers, but not in patients with Cushing's syndrome.

OBJECTIVE: The corticotrophin-releasing hormone (CRH) stimulation test has become established as a powerful tool in differentiating the source of ACTH in patients with Cushing's syndrome. Psychiatric symptoms are common in patients with Cushing's syndrome, and many patients with psychiatric illnesses may show disturbances of function of the pituitary-adrenal axis; both of these groups of patients may be receiving benzodiazepine drugs when presenting for evaluation of their possible endocrine problems. Both animal and human studies suggest that interactions occur between benzodiazepines and the hypothalamo-pituitary-adrenal axis. We have therefore evaluated the effects of a benzodiazepine drug on the pituitary-adrenal response to CRH. DESIGN: We have investigated the effects of 20 mg oral temazepam or placebo on serum cortisol and plasma ACTH after the administration of 100 micrograms i.v. human CRH in 12 healthy volunteers and in 9 patients with Cushing's syndrome. RESULTS: Temazepam significantly inhibited the peak serum/plasma levels and area under the curve for circulating cortisol and ACTH in normal subjects after CRH, but there was no such difference after temazepam in patients with Cushing's syndrome. CONCLUSIONS: Our results have shown that temazepam inhibits the pituitary-adrenal responses to human CRH in normal subjects, but not in those with Cushing's syndrome. We believe that inhibition of endogenous AVP by temazepam is the most likely explanation for our findings in healthy volunteers: the hypercortisolaemia in Cushing's syndrome suppresses the release of both endogenous CRH and AVP in portal blood which then results in abolition of the temazepam induced reduction in the pituitary-adrenal response to exogenous CRH, as seen in our patients. These effects of benzodiazepines should clearly be taken into account in patients using these compounds while undergoing endocrine assessment.

Adrenocorticotropic Hormone↗
PubMed1995

Molecular method for typing Mycobacterium ulcerans.

A cluster of Mycobacterium ulcerans infections has recently occurred on Phillip Island, Victoria, Australia. Previous cases of infection have generally been located around Bairnsdale in southeast Gippsland. The aim of this study was to determine the epidemiological relationship between these strains and other strains originating in Australia and Africa. The previously described plasmid pTBN12 was used as a probe with restriction enzyme-digested chromosomal DNA to differentiate the strains of M. ulcerans. The probe was able to distinguish 11 restriction fragment length polymorphisms (RFLPs). Forty-three strains originating in Victoria were divided into three types, i.e., V1, V2, and V3. The majority of strains (40) yielded a type V1 pattern, including strains from southeast Gippsland. Fourteen strains from Queensland yielded three additional RFLP types, i.e., Q1, Q2, and Q3. Five strains from Benin and seven strains from Zaire yielded five additional RFLP types. It is envisaged that molecular typing of M. ulcerans strains from around the world may have a great impact on understanding of the epidemiology of infection with this organism.

Australia↗
PubMed1995

The expandable metal stent for tracheal obstruction.

A 10 month old boy with stridor persisting from birth was found to have tracheal narrowing secondary to myofibromatosis of the tracheal wall. An expandable metal stent was positioned across the tracheal stenosis with immediate clinical improvement. There were no complications relating to stent insertion. The child remained clinically asymptomatic and repeat bronchoscopy at nine months' follow up showed that the stent had become completely endothelialised with no evidence of granuloma formation.

Follow-Up Studies↗
PubMed1995

Effect of peptide YY on human renal function.

Peptide YY (PYY) is released from the intestine into the circulation in response to ingestion of food. As PYY/neuropeptide Y (NPY) receptors have recently been identified in the human kidney, we examined the effect of PYY on human renal function. Male subjects (6 per group) received control infusate or PYY at 0.4 or 1.2 pmol.kg-1.min-1 intravenously for 90 min with control periods before and after. Infusion of PYY at the lower dose reproduced normal postprandial plasma concentrations and caused significant decreases in glomerular filtration rate (10% reduction), plasma renin activity (30% reduction), and aldosterone levels while increasing sodium excretion by approximately 30% (all P < 0.01). Infusion of PYY at the higher dose, which reproduced plasma levels seen during a diarrheal illness, resulted in similar changes in renal function and also reduced renal plasma flow by approximately 10% (P < 0.05). Therefore, PYY may be an important mediator of the normal postprandial natriuretic response, and PYY agonists could provide a novel approach to the treatment of patients with sodium overload.

Adult↗
PubMed1995

Pediatric spinal blastomycosis: case report.

A 5-year-old male patient presented with flank pain, limping, weight loss, and cachexia. Magnetic resonance imaging revealed destructive vertebral changes, an epidural mass, psoas abscesses, and lack of involvement of the disc spaces. Blastomyces dermatitidis was isolated from a needle aspiration specimen. Sparing of the disc spaces, an unusual finding, suggested that the spread of infection was by way of paravertebral structures and surrounding potential spaces. Management was simplified by using gadolinium contrast-enhanced magnetic resonance imaging, which indicated that the epidural mass was mainly solid, thereby obviating abscess drainage.

Amphotericin B↗
PubMed1994

Characterization of a basic serine proteinase (pI approximately 9.5) secreted by virulent strains of Dichelobacter nodosus and identification of a distinct, but closely related, proteinase secreted by benign strains.

An extracellular serine proteinase with a PI approximately 9.5 (referred to as 'basic proteinase') was purified to homogeneity, from strains of Dichelobacter nodosus that cause virulent foot-rot, by gel filtration of concentrated culture supernatant on Sephadex G-100 and chromatography on sulphopropyl-Sephadex C-25 at pH 8.6 D. nodosus strains that cause benign foot-rot do not secrete a corresponding basic proteinase with a pI of approximately 9.5. Benign strains secrete a closely related, but distinct, proteinase which has the same molecular mass and N-terminal sequences as the 'virulent' basic proteinase, but a lower pI of approximately 8.6. The basic proteinases from both strains appear to interact with other proteins present in the culture medium, which results in anomalous behavior on gel filtration. Pure D. nodosus 'virulent' basic proteinase has a molecular mass of 36 kDa and showed a low solubility at I < 0.05 precipitating quantitatively from solution as microcrystals. The proteinase shows optimal activity at pH 8.0 and is stable to heating to 55 degrees C for 30 min, but at higher temperatures activity is rapidly lost. Bivalent-metal ions (e.g. Ca2+) are required to maintain the structural integrity and stability of the proteinase; in the presence of EDTA or conditions that cause protein unfolding, the proteinase undergoes rapid and complete autolysis. Cleavage of oxidized insulin A- and B-chain showed that the basic proteinase has a broad specificity, including cleavage at lysine and arginine bonds.

Amino Acid Sequence↗
PubMed1994

Hair cells of different shapes and their placement along the frog crista ampullaris.

The list of distinguishing morphological features of hair cells includes: Type I and Type II afferent innervation, and length, shapes and arrangements of stereo- and kinocilia. We now add to this list the shapes of the hair cells themselves and their placement within the mechanosensory organ, in this case the semicircular canal. Although hair cells of the crista ampullaris of the frog are only of Type II they may now be further classified into three sub-groups according to shape: club-, cigar- and pear-shaped. The cigar- and club-shaped hair cells are each about 40% while the pear-shaped cells are about 20% of the total numbers of hair cells in the crista. The differently-shaped hair cells also distribute differently along the crista. The cigar- and club-shaped are more-or-less uniformly distributed with somewhat higher concentrations at the ends of the crista than in the center. The pear-shaped hair cells, on the other hand, are mostly concentrated toward the center of the crista. This distribution of the pear-shaped hair cells, and their shape is reminiscent of the distribution of calyceal endings (Type I hair cell) in the cristae of amniotes [Goldberg et al., Hear. Res. 49, 89-102 (1990) in Chinchilla; Fernandez et al., Soc. Neurosci. Abstr. 17, 312 (1991) in Monkey]. There are some quantitative differences between hair cells of the same shape but from different portions of the crista. For instance, pear-shaped hair cells of the center are generally of greater cross-sectional area than those of the ends.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Current methods for the measurement of growth hormone in urine.

Since the development of sensitive immunoassay procedures for the measurement of GH in urine, a urinary GH determination has been proposed as an alternative way of assessing pituitary GH secretion. Whilst studies on the clinical application of these assays have been difficult to correlate, for the reasons described, it is clear that an estimation of urinary GH has a useful role in clinical and physiological studies in both children and adults.

Acromegaly↗
PubMed1994

Religiosity, sexual intercourse and condom use among university students.

There is strong evidence that religiosity among adolescents is associated with delayed onset of sexual activity. However, research on relationships between religiosity and contraceptive practices is limited and inconsistent. This paper provides data from a survey of 374 students aged between 16 and 21 at two Brisbane universities (72.4 per cent response rate). Those who perceived religion to be important in their lives were less likely to have had intercourse. Among the sexually active sample, religious youth did not differ from their peers in recent condom use, the age at which they first used condoms or the rate of partner change. Contrary to several recent assertions in review articles, this and other empirical studies do not show that religious youth are less likely than nonreligious youth to take precautions during sex.

Adolescent↗
PubMed1994

Laboratory evaluation of the DCA 2000 clinic HbA1c immunoassay analyser.

The DCA 2000 clinical analyser for the measurement of haemoglobin A1c was evaluated for analytical quality. The analyser, which utilises inhibition of latex agglutination immunoassay, demonstrated good within-batch (1.9-3.1% CV) and between-batch (2.2% CV) imprecision, and was not affected by haemoglobin concentration. The analyser was linear throughout the analytical range, and was found to correlate well with agar electroendosmosis (r = 0.93), affinity chromatography (r = 0.97), HPLC (r = 0.90) and EIA (r = 0.98). The analyser was found to give reliable analytical results, and with its ease of use, will provide the diabetologist with HbA1c results in the clinic; although an analysis time of 9 min will limit sample throughput.

Antibodies, Monoclonal↗
PubMed1994

Cause-specific mortality in long-term survivors of breast cancer who participated in trials of radiotherapy.

PURPOSE: To examine long-term cause-specific mortality in patients irradiated for breast cancer as part of a randomized clinical trial. PATIENTS AND METHODS: We studied all available information from randomized trials initiated before 1975 in which radiotherapy was the randomized option and surgery was the same for both treatment arms. Eight such trials were identified. RESULTS: The increased all-cause mortality rate in 10-year survivors previously reported is no longer significant, although a numerical difference in favor of non-irradiated patients remains. This result was strongly influenced by the earliest trials, and more recent trials have found a nonsignificant net benefit in overall mortality associated with radiation therapy. An excess of cardiac deaths was apparent in both early and more recent trials (P < .001), but this was offset by a reduced number of deaths due to breast cancer, especially in more recent trials. CONCLUSION: The reduction of breast cancer deaths suggests that radiation therapy may have a value beyond the clearly established improvements obtainable for local control. Use of techniques that minimize cardiac dose is important in reducing the risks of adjuvant radiotherapy, especially in good-prognosis patients.

Breast Neoplasms↗
PubMed1994

Spontaneous fracture of the outlet catheter of a totally implanted catheter system (Port-A-Cath).

A case of spontaneous fracture of the outlet catheter of a totally implanted catheter system (Port-A-Cath) is presented. The outlet catheter was fractured at the entrance into the left subclavian vein twenty-one weeks after insertion and the distal part was embolized in the right ventricle. The embolized catheter fragment was retrieved by a 'goose-neck' snare via the right femoral vein. The awareness of a possible spontaneous fracture of the outlet catheter of a totally implanted catheter system (Port-A-Cath) is important to prevent accidental spillage of potent cytotoxic substances.

Adolescent↗