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Biomedical subjects

C Evans

Publications and source records attributed to C Evans.

At least 163 records · Page 9Linked to original sources
PubMed1991

Kindling-induced potentiation in the piriform cortex.

At intensities sufficient to induce epileptiform afterdischarges, repeated electrical stimulation of limbic structures can lead to the development of permanent increases in the strength of the epileptiform response (kindling). Field potentials evoked by pulse stimulation are also increased in amplitude in a number of forebrain pathways following kindling. This kindling-induced potentiation effect is similar in many respects to the 'long-term potentiation' (LTP) effect which is produced by non-epileptogenic stimulation. There are, however, some interesting differences. For example, kindling-induced potentiation can far outlast LTP. In these experiments, we attempted to determine the longevity of the kindling-induced potentiation of the response evoked in the piriform cortex by olfactory bulb stimulation, following olfactory bulb kindling. This system was targeted because both the olfactory bulb and the piriform cortex are highly reactive kindling sites. In addition, we used the paired pulse technique to monitor facilitation and inhibition in this system. Kindling was found to induce a potentiation in the piriform field potential that lasted for at least 3 months (the period of the experiment) with little or no decay. Kindling also produced a decrease in paired pulse facilitation. In some animals the net facilitation was changed to a net depression. These results are consistent with the interpretation that kindling produces an increase in recurrent inhibition in the piriform cortex. The paired pulse measures, however, returned to near baseline levels over the 3-month test period.

Animals↗
PubMed1991

Case report: hepatic and splenic calcification due to amyloid.

A case of marked hepatic and splenic calcification due to primary amyloidosis is presented. Although the patient had been treated with continuous ambulatory peritoneal dialysis, there was no evidence of a causal relationship with the calcification. Amyloid is known to have an affinity for calcium, but this radiographic manifestation has not been previously reported.

Amyloidosis↗
PubMed1991

Total body calcium in patients with inflammatory bowel disease: a longitudinal study.

1. Serial measurements of total body calcium have been made by prompt gamma-neutron activation analysis in 13 patients with inflammatory bowel disease over a mean period of 23 months. Changes in spinal trabecular bone mineral density and radial shaft bone mineral content were also assessed by using quantitative computed tomography and single photon absorptiometry, respectively. 2. The mean annual decreases (95% confidence intervals) were: total body calcium, 7.8% (-12.0 to -3.7%; P less than 0.001); spinal trabecular bone mineral density, 2.5% (-5.0 to +0.1%; 0.05 less than P less than 0.1), radial bone mineral content, 2.1% (-3.4 to -0.8%; P less than 0.01). 3. No significant correlations were found between rates of change of the three variables. However, there were significant positive correlations between the baseline values for total body calcium and radial bone mineral content (r = 0.638, P less than 0.05), spinal bone mineral density and radial bone mineral content (r = 0.854, P less than 0.01), and total body calcium and spinal bone mineral density (r = 0.876, P less than 0.001). 4. These results demonstrate rapid decreases in total body calcium in patients with inflammatory bowel disease which, in conjunction with the significant decrease in radial shaft bone mineral content, indicate increased rates of cortical bone loss. Whilst values for bone mass at different skeletal sites showed positive correlations within individuals, no relationship was found between the rates of change in bone mass at these sites. 5. The rapid bone loss observed in some subjects emphasizes the importance of early detection of osteoporosis by bone densitometry and the need for effective prophylactic measures to be established in this group of patients.

Absorptiometry, Photon↗
PubMed1991

Covert bacteriuria: long term follow up.

In a longitudinal prospective study 58 schoolgirls with covert bacteriuria were followed up for an average of 11.2 years (range 8.8 to 13.5 years). Intravenous urography was carried out at the start of the study (aged 4 to 11 years) and after completion of the follow up period (aged 14.8 to 22.3 years). After random allocation 27 of these girls received intermittent treatment for covert bacteriuria for the first four years and the control group received no treatment. The effect of covert bacteriuria, treatment, vesicoureteric reflux, and reflux nephropathy at presentation on the final renal length, progression of scarring, and development of new scars was analysed. No new scars were found in girls with bilaterally normal kidneys. In girls with reflux nephropathy, three kidneys showed progression of existing scars and two kidneys developed new scars. It was shown that final renal length was not influenced by vesicoureteric reflux or treatment, but reduced renal length at final assessment was associated with the presence of kidney scarring at initial assessment.

Bacteriuria↗
PubMed1991

Polycystic kidney disease re-evaluated: a population-based study.

A genetic register of all known cases of autosomal dominant polycystic kidney disease occurring in South and Mid-Wales has been established. In a population of 2.1 million, 209 families with affected members were identified, 303 of whom are currently alive, 70 on renal replacement therapy. An additional 551 cases would be predicted amongst family members at 50 per cent and 25 per cent risk, giving an apparent prevalence of 1:2459 in the general population. Five possible new mutations were seen where adults with phenotypic autosomal dominant polycystic kidney disease had both parents alive, age greater than 55 years with no cysts visible on ultrasound. The take-on rate for renal replacement therapy increased during 1970-79 but has apparently reached a plateau of 4.8 cases per million population per year over the last 8 years, despite a rapidly increasing acceptance of uraemic patients as a whole (72/10(6)/year in 1988-89). Considerably more patients with autosomal dominant polycystic kidney disease aged over 50 years were started on treatment in 1980-89 than in 1970-79, but the survival overall improved with time. All cases of autosomal dominant polycystic kidney disease reaching end-stage renal disease are now being treated, but the apparent clinical prevalence of this condition in our region is less than half the supposed gene frequency, suggesting that undiagnosed cases have a benign prognosis.

Adolescent↗
PubMed1991

Polycystic ovary syndrome and bulimia.

One hundred fifty-three patients classified as suffering from polycystic ovarian syndrome (PCOS) and 109 patients who were suffering from a clear organic disorder or endocrinopathy received the bulimia investigation test (Edinburgh) (BITE) questionnaire for abnormal eating behaviors. Patients with PCOS showed a significant increase in their mean BITE score for approximately a third had abnormal eating patterns, and 6% have scores suggestive of clinical bulimia compared with only 1% of women in the group with organic endocrinopathies. The work suggests that women with PCOS should be screened for abnormal eating behaviors and raises the possibility that treatment by psychological means should be considered when abnormal eating behaviors are present.

Analysis of Variance↗
PubMed1991

Comparison of intravenous versus subcutaneous recombinant human granulocyte-macrophage colony-stimulating factor in patients with primary myelodysplasia.

The primary objective of this study was to compare the toxicity and hemopoietic effects of s.c. and i.v. recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) in patients with primary myelodysplasia. Twenty patients were treated in this phase I crossover-designed study. In three groups of patients, the dose of rhGM-CSF was escalated from 60 to 250 micrograms/m2/day. Each patient was to receive 2 weeks of i.v. (daily 2-h infusion) and s.c. (twice daily) rhGM-CSF separated by a 2-week rest period. The decision to start with i.v. or s.c. administration was by random selection. Toxicity was comparable between i.v. and s.c. administration. At the highest dose level, 63% (five of eight) of the patients developed moderate to severe toxicity. Increases in the absolute neutrophil count showed a dose-response relationship and were more pronounced with s.c. than i.v. administration. Failure to grow in vitro granulocyte-macrophage colonies or a hypocellular marrow (less than or equal to 30%) predicted for a poor response to therapy. No patient had a platelet or a reticulocyte response. No patient progressed to acute leukemia. Compared to a 2-h infusion of i.v. rhGM-CSF, s.c. administration is more myelostimulatory without an increase in toxicity.

Adolescent↗
PubMed1990

Human macrophage colony-stimulating factor induces macrophage colonies after L-phenylalanine methylester treatment of human marrow.

Macrophage-colony stimulating factor (M-CSF) has well-known effects on murine bone marrow, but its colony stimulating activity for human bone marrow is controversial. After treatment of human bone marrow with L-phenylalanine methylester (PME), macrophage-colonies (CFU-M) were induced by M-CSF in a dose-dependent fashion. The optimal concentration of recombinant human-macrophage colony stimulating factor (rhM-CSF) was 1,000 U/mL. Purified human urine M-CSF had colony stimulating activity similar to rhM-CSF. Further studies were performed to determine the factors responsible for the enhanced CFU-M formation from PME treated marrow. Compared with nylon wool and carbonyl iron monocyte depletion methods, PME eliminated significantly more monocytes and myeloid cells. This observation suggested that these cells may release hematopoietic inhibitory factors for CFU-M. Low concentrations (1%) but not normal (10%) concentrations of blood monocytes were inhibitory (mean inhibition, 48%) to CFU-M. High concentrations of monocytes (50%) augmented CFU-M colonies. HL-60 conditioned media was used to simulate secretory products of early myeloid cells. HL-60 conditioned media (1%) inhibited CFU-M formation but not granulocyte macrophage or granulocyte colonies. We conclude that M-CSF has colony stimulating activity for human marrow that can be recognized after removal of inhibitory cells by PME treatment.

Bone Marrow↗
PubMed1990

High-dose cytosine arabinoside and L-asparaginase therapy for poor-risk adult acute nonlymphocytic leukemia. A retrospective study.

The effectiveness and toxicities of high-dose cytosine arabinoside with L-asparaginase (HiDAC-ASNase) were evaluated in 41 patients with "poor risk" acute nonlymphocytic leukemia (ANLL). Twenty-four patients had either refractory or relapsed primary ANLL, and 17 had ANLL secondary to prior cytotoxic chemotherapy or an underlying hematologic disorder. The overall complete remission (CR) rate was 37%. The CR rates for primary and secondary ANLL were almost identical. Furthermore, advanced age alone did not adversely influence the CR rate. The median CR duration was 302 days with no differences between primary and secondary ANLL. The induction death rate was 24%. Predictors for induction deaths included poor initial performance status, fever at the time of presentation, low cholesterol and/or albumin, and an initial bone marrow aspirate with greater than 50% blasts. These data indicate that HiDAC-ASNase is a moderately effective regimen for patients with poor prognosis ANLL including secondary ANLL.

Adolescent↗
PubMed1990

Suspected adverse reactions to medicines during 1989.

There was an increase in reports of suspected adverse reactions to veterinary medicines in 1989 with 329 reports (compared with 206 in 1988), from veterinary surgeons, farmers and the public, comments the Veterinary Medicines Directorate (VMD). Suspected adverse reactions to clostridial/pasteurella vaccines in sheep were a dominant feature and important experience was gained both in terms of liaison with the farming press, and in handling large scale incidents involving PML products. The general trend towards increased reporting of adverse drug effects continues. The UK is the only EC member state to have a PML system and the VMD is looking with some urgency at ways of ensuring the more representative reporting of all categories of drug. Substantial liaison with the veterinary pharmaceutical industry occurred during the year and 204 product reports were requested from companies.

Analgesics↗