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Biomedical subjects

J Marks

Publications and source records attributed to J Marks.

At least 163 records · Page 9Linked to original sources
PubMed1986

Growth polarity and cytokinesis in fission yeast: the role of the cytoskeleton.

The distribution of F-actin in the fission yeast Schizosaccharomyces pombe was investigated by fluorescence microscopy using rhodamine-conjugated phalloidin. Fluorescence was seen either at the ends of the cell or at the cell equator. End staining was predominantly in the form of dots whilst equatorial actin was resolved as a filamentous band. The different staining patterns showed a close correlation with the known pattern of cell wall deposition through the cell cycle. In small, newly divided cells actin was localized at the single growing cell end whilst initiation of bipolar cell growth was coincident with the appearance of actin at both ends of the cell. As cells ceased to grow and entered cell division, a ring of actin was seen to anticipate the deposition of the septum at cytokinesis. The relationship between actin and cell wall deposition was further confirmed in three temperature-sensitive cell division cycle (cdc) mutants; cdc10, cdc11 and cdc13. Immunofluorescence microscopy of S. pombe with an anti-tubulin antibody revealed a system of cytoplasmic microtubules extending between the cell ends. The function of these was investigated in the cold-sensitive, benomyl-resistant mutant ben4. In cold-grown cells actin was seen to form conspicuous filamentous rings around the nucleus. The origin of these and the possible role of microtubules in the cell-cycle-dependent rearrangements of F-actin are discussed.

Actins↗
PubMed1985

Restriction fragment length polymorphism of the gene encoding the alpha chain of the human T cell receptor.

Two allelic forms of the T cell antigen receptor alpha chain gene were discerned by restriction fragment length polymorphism (RFLP) employing the T cell antigen receptor alpha chain probe pGA5, and the restriction enzyme Bgl II. Analysis revealed that the polymorphic fragments are detected by a probe specific for the constant region exon of the T cell antigen receptor alpha chain gene. Furthermore, the polymorphic fragments were shown to segregate within families. The two allelic forms yield two homozygous states, 3.2/3.2 and 2.9/2.9, at a frequency of 76.5 and 2.9%, respectively, within the normal population. The heterozygous state was observed in 20.6% of the population. The discovery of allelic forms of both the alpha and beta chains of the T cell antigen receptor genes may provide a unique opportunity to study heritable markers of T cell function in several human diseases.

Bacterial Proteins↗
PubMed1985

Pilonidal sinus excision--healing by open granulation.

A prospective study is reported of 100 pilonidal sinus excisions healing by open granulation. Delays in healing appeared to be due to infection, particularly by anaerobic bacteria. Comparisons are made between three groups studied consecutively - 30 wounds not treated with antibiotics, 20 given a fixed two-week course of metronidazole and 50 managed flexibly. In this last group, wound management was determined by clinical appearance; 24 wounds were clinically healthy throughout and received no antibiotic while 26 looked unhealthy initially or after an interval and were treated with metronidazole, supplemented in some cases with erythromycin. The best results were obtained in the group managed flexibly. It is considered that the problems of delayed healing are due to excisions which leave a wound of a shape ill-designed to maintain good drainage. Unhealthy wounds should be re-shaped if possible and treated early with a combination of metronidazole and erythromycin.

Bacteria, Anaerobic↗
PubMed1985

The disinfection of silicone-foam dressings.

The efficiency of four commonly used antiseptics, chlorhexidine, povidone-iodine, cetrimide and sodium hypochlorite was compared in the disinfection of silicone-foam dressing used in the management of open granulating wounds. An in vitro model was first used to determine the minimum effective concentration of each antiseptic in killing a standard culture of Pseudomonas. The appropriate concentrations were then compared in comparative studies of clinical wounds. Chlorhexidine proved to be the most effective antiseptic, povidone-iodine and cetrimide were moderately successful, but sodium hypochlorite gave poor results. A subsidiary study looked at the problem of wound irritation by carry-over of the antiseptic. A rinse of the dressing after disinfection prevented irritation by chlorhexidine without compromising its antibacterial effect, but this procedure sometimes failed to prevent irritation when using the other antiseptic agents. It is concluded that chlorhexidine is the preferred cleansing agent in the management of silicone-foam dressings on both grounds of bacteriological efficiency and lack of wound irritation. It should be noted that Hibitane concentrate used in this work contains non-ionic detergent and a stabilizing agent. Pure preparations of chlorhexidine may not behave similarly.

Anti-Infective Agents, Local↗
PubMed1984

Safety and efficacy of esmolol (ASL-8052: an ultrashort-acting beta-adrenergic blocking agent) for control of ventricular rate in supraventricular tachycardias.

Esmolol (ASL-8052) is a new intravenous beta-adrenergic blocking agent that has exhibited both cardiac selectivity and an extremely short half-life in animal studies. To assess its clinical efficacy, 16 patients were studied with a rapid ventricular rate associated with atrial flutter (n = 2), atrial fibrillation (n = 10), atrial tachycardia (n = 2) and multifocal atrial tachycardia (n = 2). During a 30 minute control period of observation, the ventricular rate ranged from 121 to 150 beats/min (mean 133.2 +/- 10.6). Using a double blind crossover method, esmolol was infused intravenously for a maximum of 60 minutes. Infusions of 50, 100, 150, 200, 250 and 300 micrograms/kg per min were given in consecutive 5 minute periods (during the first minute of each period, a loading dose of 500 micrograms/kg was given). Not all patients received the maximal dose. A response was defined as conversion to sinus rhythm or a 20% reduction in ventricular rate. One patient with atrial fibrillation associated with the Wolff-Parkinson-White syndrome did not respond. In the remaining 15 patients, their highest esmolol infusion rate was maintained for an additional 30 minutes. This resulted in a reduction in ventricular rate to a mean of 97.8 +/- 12.9 beats/min (range 72 to 119) (p less than 0.001). Conversion from flutter/fibrillation to sinus rhythm occurred in two patients. During the infusion, six had transient asymptomatic hypotension that was mild and manageable. After infusion, ventricular rate and blood pressure returned rapidly toward control values within 25 minutes in patients without conversion to sinus rhythm.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1984

A randomized double-blind comparison of PUVA-etretinate and PUVA-placebo in the treatment of chronic plaque psoriasis.

Twenty-eight patients with chronic plaque psoriasis affecting 20-40% of their body surface were treated with either PUVA and placebo (thirteen patients) or PUVA and etretinate (0.75 mg/kg) (fifteen patients). PUVA was given three times a week for a maximum of 10 weeks after a 2-week period on placebo or etretinate alone. Four patients failed to clear with PUVA and placebo compared with one patient with PUVA and etretinate, and the mean total UV-A dose to clear was lower with etretinate (mean = 62.1 J/cm2) than with placebo (mean = 77.3 J/cm2) but none of these differences were significant. Because the additional response to etretinate was only marginal, whilst unwanted effects were common, we found no advantage in adding etretinate to PUVA.

Chronic Disease↗
PubMed1984

A comparison of PUVA-etretinate and PUVA-placebo for palmoplantar pustular psoriasis.

Seventeen patients with palmoplantar pustular psoriasis and three with hyperkeratotic psoriasis of palms and soles were treated with either PUVA-etretinate (1 mg/kg) or PUVA-placebo. Patients were randomly allocated to each group and the trial was conducted according to a double-blind protocol, so far as the side-effects of etretinate made this possible. PUVA was given three times a week for a maximum of 18 weeks, after 2 weeks on daily placebo or etretinate alone. All ten patients in the PUVA-etretinate group cleared, but there were four failures in the PUVA-placebo group (P = 0.03). The PUVA-etretinate treated patients required significantly fewer PUVA treatments (13.1 +/- 2.9; mean +/- s.e.) and cleared in a significantly shorter time (30.3 +/- 7.1 days) than the PUVA-placebo group (23.2 +/- 4.2 treatments; 59.2 +/- 11.5 days, P less than 0.05). The cumulative UV-A dose to clear was less in the PUVA-etretinate group (53.9 +/- 18.5 J/cm2) than the PUVA-placebo group (113.1 +/- 33.4 J/cm2). This difference was not significant due to the exceptionally large dose of UV-A used on one patient but the results were significant when it was excluded. The therapeutic advantage of adding etretinate to PUVA is offset by the side-effects of cheilitis, hair loss and peeling skin which occurred in eight of the ten PUVA-etretinate patients, and an increase in fasting triglyceride concentrations and serum alkaline phosphatase activity.

Etretinate↗
PubMed1984

Is there a place for beta-carotene/canthaxanthin in photochemotherapy for psoriasis?

A randomised study of beta-carotene/canthaxanthin or placebo in chronic plaque psoriasis has failed to show any significant difference in the time to clearing and in the total accumulative dose required. Orange discolouration and hyperpigmentation of the skin occurred in the test group. In patients studied outside the randomised comparison, 2 patients who had not been able to tolerate PUVA therapy because of burning were subsequently able to do so when beta-carotene/canthaxanthin was added to their treatment regimen.

Adolescent↗
PubMed1983

The impact of publicly funded perinatal care programs on neonatal outcome, Georgia, 1976-1978.

The State of Georgia administers three publicly funded perinatal care programs for medically high risk and/or low-income women: the High Risk Pregnancy Program, the Medicaid Program, and the Maternal and Infant Care Projects. To assess the impact of these programs on infant health, we compared the birth weight distribution and neonatal mortality rates of infants born to women in each program with those of infants of a nonfunded group of women with less than 12 years' education. Infants of women in publicly funded groups were more likely to weigh less than or equal to 2,500 gm at birth than those of women in the nonfunded group. Neonatal mortality rates for publicly funded groups were similar to those of the nonfunded group. The neonatal mortality rates for infants of birth weight less than or equal to 2,500 gm of publicly-funded women were significantly lower than those of the nonfunded women. There were no significant differences between groups for neonatal mortality rates for infants of birth weight greater than 2,500 gm. These findings suggest that publicly funded perinatal care programs may improve neonatal survival of infants of birth weight less than or equal to 2,500 gm of low-income mothers.

Adult↗