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Biomedical subjects

J Clarke

Publications and source records attributed to J Clarke.

At least 235 records · Page 13Linked to original sources
PubMed1990

V beta 5 and V beta 8 memory T cells in adults and infancy: co-ordinated increase in response to early antigen stimulus.

Blood mononuclear cells (MNC) expressing the T cell receptor V beta gene families were identified with the monoclonal antibodies 1C1 (V beta 5) or Mx6 (V beta 8). These cells were typed for expression of the T200 common leucocyte antigen with the CD45RA antibody defining the 220-kD variant (which characterizes naive cells) and the UCHL1 antibody which defines the 180-kD variant (characterizing memory cells). Of adult MNC, 3 +/- 0.44% stained for V beta 5 and 4.12 +/- 0.26% stained for V beta 8; similar results were obtained in a group of infants aged less than 3 months, who were exposed to antigen stimulus in the form of infection and/or blood transfusion. While the total percentages of V beta 5 and V beta 8 cells in the blood of adults were not correlated, the proportions of these cells expressing CD45RO was positively correlated. A similar trend which did not reach statistical significance was present in a group of infants. A minority of the infants studied showed transient deviations from the mean established for adults. The results suggest that naive and memory T cell populations have similar frequencies of V beta 5 and V beta 8 expressing cells, and that age does not affect the frequency of usage of either of these V beta families.

Adult↗
PubMed1990

The sexual behaviour and knowledge about AIDS in a group of young adolescent girls in Leeds.

A questionnaire was given to 56 sexually active girls 12-16 years old, in a juvenile assessment centre or attending a genitourinary medicine clinic. Sexual behaviour, drug use, contraceptive practice and knowledge and attitudes about AIDS were evaluated. The girls were similar in demographic characteristics from both centres and were regarded as one group. Sexual experience ranged from 1 partner ever to 70 clients/week; 19 girls had contracted a sexually transmitted disease at some time. Half had never used a contraceptive. Twenty eight had used illicit drugs, with two girls experimenting with intravenous misuse. Misconceptions about modes of transmission of HIV were common, but most girls knew some basic facts about the virus. Most girls realised they were at risk, were anxious about contracting HIV infection in the future, but had not modified their behaviour in terms of condom usage. This study indicates that high risk adolescents need to be targeted for effective health education in order to modify behaviour patterns which put them at risk of acquiring HIV in the future.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Asymptomatic herpes simplex virus shedding from the genital tract whilst on suppressive doses of oral acyclovir.

Forty-eight patients were recruited into a study of continuous oral acyclovir therapy for the suppression of recurrent genital herpes simplex virus (HSV) infection. Seven of these patients were shown to shed HSV in the absence of clinical signs or symptoms whilst on medication. The asymptomatic shedders did not differ significantly from the rest of the group in terms of age, interval from first attack to enrollment or number of recurrences prior to enrollment. Only one patient admitted to poor compliance as a trigger to asymptomatic HSV shedding. Failure to suppress asymptomatic shedding during prophylactic acyclovir therapy may have implications for sexual transmission to partners and vertical transmission to neonates and requires further study.

Acyclovir↗
PubMed1990

The timing of amputation for lower limb trauma.

We reviewed 35 patients who had an amputation following the failure of treatment for severe lower limb trauma. Seven of the amputations were for ischaemia, within one month of injury; 13 were between one month and one year for infection complicating loss of wound cover in un-united fractures; and 15 were later than one year after injury, mainly for infected non-union. The latter group of patients had had an average of 12 operations and 50 months of treatment, including eight months in hospital. We used a new limb injury score based on damage to the individual tissue elements; this indicated that, even in the absence of neurovascular injury, the presence of severe damage to skin, bone and muscle, with wound contamination, particularly in the lower tibia, had a poor prognosis. We therefore recommend, to avoid multiple operations, with prolonged hospitalisation and suffering, that these patients should have early independent review by orthopaedic and plastic surgeons with the aim of establishing an accurate prognosis for the salvage of a useful limb.

Adolescent↗
PubMed1990

Penetration rate of two pesticide carriers at a large used-tire storage facility in Chicago, Illinois.

During August 1987, a large and concentrated infestation of Aedes albopictus was discovered on the property of a tire recapper and gasket manufacturer in Chicago, IL, in a densely populated urban environment. The infestation called for special abatement procedures because of the large number of tires and the varied ways they were stacked. An effective method for delivering pesticides into the cavity of each tire is described. Corncob granules, when applied to stacked tires, effectively penetrated this larval habitat at rates of 85% in column-stacked piles, 93% in random-stacked piles and an average of 95% in shingle-stacked piles. By comparison, gypsum pellet carriers sustained penetration rates of 37% in shingle-stacked piles and 87% in random-stacked piles.

Aedes↗
PubMed1989

A comparison of the effects of various stimulatory agents on t-PA secretion by normal and malignant cell lines.

Succinyl con A and acetyl con A both stimulated epithelial cells to produce similar yields of tissue plasminogen activator (t-PA) to those previously obtained with native con A. However, unlike con A, the derivatized lectins did not adversely affect cell morphology and viability, and cells treated with succinyl con A could secrete t-PA for a prolonged period. Con A and the two derivatives produced similar morphological effects in Bowes melanoma cells, but t-PA production was not increased. Elevated cyclic nucleotide concentrations did not affect t-PA production from epithelial cells, but calcium ionophore treatment generated t-PA yields similar to those obtained with lectins. Azacytidine, which enhanced t-PA production from epithelial cells, did not increase yields from Bowes melanoma cells, and also sodium butyrate, reported to increase t-PA yields from human endothelial cells, had no effect on either cell line.

Azacitidine↗
PubMed1989

A phase II study of mitozantrone in advanced carcinoma of the ovary.

A total of 37 patients with advanced epithelial ovarian cancer were treated with single-agent mitozantrone at a dose of 12-16 mg/m2. All patients had received previous chemotherapy, including a platinum compound in 36. In all, 35 patients were evaluable for response. One patient (3%) achieved a partial response lasting 4 months. Treatment was well tolerated, and at the doses used in this study significant bone marrow suppression was uncommon. Our results suggest that mitozantrone has only minimal activity in previously treated ovarian cancer. However, the possibility of its useful activity in first-line treatment or at higher doses has not been excluded.

Adult↗
PubMed1989

A dose finding study of prochlorperazine as an antiemetic for cancer chemotherapy.

This phase I study determined the maximum tolerated dose of prochlorperazine when used as an antiemetic prior to cytotoxic chemotherapy. Initially, cohorts of three patients were given prochlorperazine at escalating doses of 0.2, 0.4, 0.6, 0.8, 1.0 and 1.2 mg/kg as an intravenous infusion over 20 min. The maximum tolerated dose was 1.2 mg/kg. The dose-limiting toxicity was hypotension which was reversed by a fluid load. The other major toxicities were extrapyramidal reactions which were dose related. All patients at the 1.2 mg/kg dose reported restlessness while five of six were restless and two of six at 1.0 mg/kg had muscle spasms. Two of seven patients reported restlessness at the 0.8 mg/kg level. Sedation and dry mouth were reported at all dose levels but were more common at higher doses. Prochlorperazine in plasma was assayed by high performance liquid chromatography with electrochemical detection and pharmacokinetics were determined for three patients at the 1.0 mg/kg dose level. The average terminal elimination half life was 7.6 +/- 0.4 h, plasma clearance 27 +/- 5 ml/min/kg and volume of distribution 17.7 +/- 4.5 l/kg. The dose of prochlorperazine recommended for further studies of antiemetic efficacy is 0.8 mg/kg intravenously.

Antiemetics↗
PubMed1989

Continuous hemodynamic monitoring by esophageal Doppler.

A new 5.1-mHz continuous wave esophageal Doppler system is described for continuous hemodynamic monitoring in ventilated patients. Information is obtained from the size, shape, and changes in shape of the velocity waveforms of descending aortic blood flow. Minute distance, the product of waveform area (stroke distance) and heart rate, provides a measure of cardiac output. Good agreement between this technique and thermodilution was shown for cardiac output changes with 238 paired measurements made in 38 patients. The coefficient of variation was lower for Doppler (3.8%) than for simultaneous thermodilution measurements (6.2%). Seventy-eight changes in left ventricular filling, systemic vascular resistance, or inotropic state produced consistent alterations in waveform shape with a narrow-based waveform being indicative of hypovolemia. This development marks a significant advance in the technique and provides a useful alternative to invasive hemodynamic monitoring, both in the ICU and perioperatively.

Adult↗