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Biomedical subjects

J McConnell

Publications and source records attributed to J McConnell.

At least 55 records · Page 3Linked to original sources
PubMed1994

Androgenesis and gynogenesis are not causative in early pregnancy loss in humans.

OBJECTIVE: Androgenetic and gynogenetic embryos in the mouse have been shown to fail early in development, exhibiting many features that are similar to those seen in early pregnancy loss in humans. Because androgenetic or gynogenetic abortuses contain the genetic complement from a single paternal or maternal genome, we used locus-specific minisatellite probes to determine individual genetic relationships and parentage from samples of parental blood and abortus tissue, to investigate whether androgenesis and gynogenesis contribute to the cause of early pregnancy loss. STUDY DESIGN: We carried out prospective recruitment over 2 years of 145 patients admitted to a teaching hospital in Cambridge with ultrasonographic confirmation of early pregnancy failure. RESULTS: Blood and products of conception suitable for complete analysis were obtained from 75 cases. Twenty-seven (56%) of the 48 samples that could be karyotyped had normal chromosome complements, with trisomy 16 the most frequent aberration (5/21). Both paternal and maternal genomic contributions to the abortuses were found in all cases investigated, irrespective of the karyotypes of the tissue. Germline mutations were detected in six of 42 (7.1% per gamete) hybridizations with lambda MS1 and in one of 15 (3.3% per gamete) with p lambda g3, which is higher than the rate estimate for the general population. No inappropriate paternity was detected. CONCLUSION: Androgenesis and gynogenesis are unlikely to be causative in the cause of human early pregnancy loss, but germline mutations even in the presence of a normal karyotype could be influential.

Abortion, Missed↗
PubMed1993

ICAAC 1993.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Risk management in health care: where did it come from and where is it going?

This article reviews some of the historical developments contributing to the evolution of risk management and its current role in health care. The scope of activities and concerns that today's health care risk managers address and the need for involvement by the entire health care team are discussed.

Hospital Administration↗
PubMed1993

Use of transdermal clonidine in chronic hemodialysis patients.

Large fluctuations of blood pressure are commonly experienced by hypertensive, chronic hemodialysis patients. Many patients hold anti-hypertensive medication immediately prior to dialysis to prevent intradialytic hypotension. Weekly dosing of continuously released antihypertensive agents may result in better blood pressure control than conventional daily dosing. To evaluate the effect of weekly transdermal clonidine on this problem, we compared intra- and interdialytic blood pressure control and side effects during six weeks of transdermal clonidine monotherapy and six weeks of conventional oral antihypertensive treatment in nine stable chronic hemodialysis patients. Since transdermal clonidine is recommended for mild to moderately severe hypertension and since clonidine is excreted by the kidneys and removed by hemodialysis, we also evaluated blood pressure control and clonidine levels while utilizing high-dose transdermal clonidine, up to 0.12 mg per week. Intradialytic blood pressure was monitored twice weekly during the weeks 3-6 of transdermal clonidine and conventional therapy. Twenty-four hour blood pressure was monitored weeks 3 and 6 of each study phase. Plasma clonidine levels were measured by HPLC in 11 patients. Transdermal clonidine monotherapy failed to adequately control blood pressure in 6 of 21 chronic dialysis patients with moderate to severe hypertension. No significant difference in intra- or interdialytic blood pressure control or side effects (including dry mouth or thirst) was found comparing conventional to transdermal clonidine therapy. While not statistically different, heart rate was lower during transdermal clonidine therapy compared to conventional therapy, especially at very high doses. Despite a mean hemodialysis clearance of clonidine of 59.2 +/- 7.8 ml/min, clonidine levels remained therapeutic beyond one week.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Cutaneous↗
PubMed1992

Indications for treatment of benign prostatic hyperplasia. The American Urological Association Study.

BACKGROUND: In 1990, a pilot study was begun that evaluated benign prostatic hyperplasia (BPH) at five clinical institutions. Data management and coordination of this study was performed at the Medical Practices Evaluation Center at Massachusetts General Hospital. Because of decreased patient enrollment, one institution was dropped. This was a randomized, prospective, clinical study that provided an initial overview of the trial and a rationale for the project. METHODS: Patients with clinically significant signs and symptoms of BPH were enrolled in this study. A symptom index consisting of seven items was used to document patient complaints of prostatic enlargement. Prostate size was determined using ultrasonography. Uroflowmetry (peak flow and mean flow) and residual urine volumes were documented. Abdominal ultrasonography was performed to rule out the presence of a dilated upper urinary tract. Cystoscopy was completed to determine the extent of prostatic and bladder neck obstruction. Trabeculations or cellules in the bladder, if present, were also documented. Conclusions. Preliminary results were obtained. The operative and nonoperative options depending on prostate size are shown in the figures of this article. The use of an interactive video disc has been beneficial in explaining the risks and benefits of each treatment option applicable to the patient in this randomized, controlled study.

Aged↗
PubMed1992

The effect of obstruction on the developing bladder.

Congenital bladder obstruction causes significant immediate and long-term consequences yet its pathophysiology remains poorly understood. A model of early fetal bladder obstruction in sheep has been developed to study the response of the developing bladder to high grade obstruction, with particular emphasis on the regulation of growth and development. Congenital bladder obstruction was produced in fetal sheep at 60 days of gestation and studied at 95 days of gestation (14 sheep) or term (12 sheep). A total of 24 age-matched normal sheep served as controls. Bladders were analyzed by total weight, stereological estimation of smooth muscle cell size, number and total mass, deoxyribonucleic acid concentration, muscarinic cholinergic receptor density, myosin isoform analysis and/or passive cystometrics. Congenital bladder obstruction caused a 4.6 times increase in bladder weight at term reflecting a 5.8 times increase in smooth muscle mass. This increase was predominantly that of cellular hypertrophy and less so of hyperplasia, based upon increased cell volume, increased protein-to-deoxyribonucleic acid ratio, and no significant increase in total cell number. Muscarinic cholinergic receptor number per smooth muscle cell increased 3.2 times but it did not change relative to myosin content. The ratio of myosin heavy chain isoforms SM1:SM2 is developmentally regulated and was seen to change from 1.6 at 100 days of gestation to 1.13 at term in normals. After 5 weeks of obstruction SM1:SM2 was 1.27 and it was 1.25 at term, indicating an effect on the developmental regulation of smooth muscle. Rapid fill cystometry in vivo measured the rate of stress relaxation to assess accommodative properties. The half-decay time was increased in all 3 obstructed bladders tested to greater than 15 seconds at 50% capacity (normal less than 5 seconds), suggesting reduced compliance. This study shows that an in utero model of bladder obstruction is feasible. Congenital bladder obstruction produces a variety of structural, biochemical and functional changes in the developing bladder indicative of alterations in the regulation of growth and differentiation.

Actins↗