Biomedical subjects
Publications and source records attributed to A Fraser.
Blood pressure estimation is probably the most frequent and least accurate clinical measurement carried out by both nursing staff and doctors. The more the observer realizes that this routine and apparently simple procedure needs skill, strict observance of rules, and a clear understanding of the mechanics involved so will his or her readings be valid.
The differential leukocyte count is very important in the diagnosis of various leukocyte disorders. Newer automated haematology counters can now perform differential leukocyte count, thus reducing the dependence on experienced medical technologists. The Technicon H.1 analyser (Technicon Instruments Corp., New York, USA) can perform even more complicated tasks like flagging abnormal cells, generating cytograms based on cell size and cytochemistry. In this paper we report on the useful cellular characteristics of the various leukocyte disorders as measured by the Technicon H.1 analyser.
Prosthetic mitral valve regurgitation was evaluated by both pulsed Doppler ultrasound and left ventriculography. Pulsed Doppler ultrasound was found to have only a 20% sensitivity in detecting prosthetic mitral valve regurgitation documented by left ventriculography. Possible reasons for this poor sensitivity include 1) an eccentric jet not identified by the small pulsed Doppler sample volume; 2) prosthesis interference with the Doppler signal in the apical four chamber view; and 3) the large angle of incidence between the pulsed Doppler signal and the regurgitant jet. Mitral insufficiency, especially when not severe, may be missed by this technique. Care must be taken in interpreting negative results from a pulsed Doppler ultrasound evaluation of a prosthetic mitral valve.
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We report five episodes of carbamazepine (CBZ) intoxication in four patients. Clinically, there were four distinct stages: I--coma, seizures (CBZ levels more than 25 micrograms/ml [105 mumol/l]); II--combativeness, hallucinations, choreiform movements (15 to 25 micrograms/ml [65 to 105 mumol/l]); III--drowsiness, ataxia (11 to 15 micrograms/ml [45 to 65 mumol/l]); and IV--potentially catastrophic relapse (less than 11 micrograms/ml [45 mumol/l]). Pharmacokinetic studies revealed a prolongation of the CBZ half-life, elevation of the CBZ-epoxide/CBZ ratio, and emergence of CBZ-epoxide as a significant toxic metabolite. A treatment approach is proposed including repeated gastric lavage, detection of an insoluble tablet coagulum, electrolyte monitoring, avoidance of cathartics, and treatment of seizures with diazepam and phenytoin.
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Infants weighing 1500 g at birth requiring either intermittent positive pressure ventilation or continuous positive airway pressure by 12 hours of age were entered in a randomized double blind controlled trial to test the efficacy of early intravenous indomethacin therapy in preventing chronic pulmonary disease of prematurity. Of the 30 newborns enrolled, 15 were treated with indomethacin and 15 were treated with placebo at 12, 24 and 36 hours of age. The groups were similar for birth weight, gestational age, sex, hyaline membrane disease and intracranial hemorrhage. Infants in the placebo group were successfully weaned from intermittent positive pressure ventilation at an earlier age than infants in the indomethacin group (p less than 0.05). Furthermore, chronic pulmonary disease of prematurity was similar in the two groups despite a reduction in the incidence of patent ductus arteriosus in the indomethacin group.
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A simple photographic technique was used to assess the objective response of hirsute women to treatment with cyproterone acetate (CA). The skin in front of the left ear was shaved and photographs taken immediately and after 1 week, and hair growth per week estimated by averaging the length of 20 hairs in the magnified photographs. The precision, repeatability and patient acceptance of the method were found to be satisfactory. Basal hair growth rates were 2.28 +/- 0.4 mm/week (mean +/- SD, n = 34) and showed a significant correlation with hirsutism scores derived from a standard physician-rated scale. During therapy with CA the mean (+/- SD) improvement in hair growth rate was 19 +/- 13%, whereas physician-rated hirsutism scores improved by 33 +/- 20%. The reduction in hair growth rate showed no significant correlation with improvement assessed using subjective rating by either physician or patient. The greater improvement in physician-rated scores compared with hair growth rate assessment suggests that hair shaft width, colour and other factors may be as important as hair length when assessing treatment response.
T cell subsets have been quantitated in 40 human cardiac biopsies to characterize the surface phenotype of T lymphocytes involved in acute rejection. Seventeen biopsies were from patients receiving conventional immunosuppression, and 18 were from patients receiving cyclosporine (Cys) as the major immunosuppressive drug. Five biopsies were from nontransplanted hearts. Frozen sections were treated with monoclonal antibodies of the Leu series and an immunoperoxidase technique to determine numbers of Leu 4 (T3 or pan-T-cell), Leu 2a (T8 or suppressor/cytotoxic), and Leu 3a (T4 or helper/inducer) positive cells. Biopsies from patients on conventional immunosuppression during rejection contained 68.3 +/- 10 infiltrating leukocytes/0.048 mm2 of the biopsy, of which 47 +/- 7.4% were T cells. Most of the T cells (86%) were of the 2a/T8 phenotype. In contrast, nonrejecting hearts contained substantially fewer infiltrating leukocytes (43.3 +/- 18.8/0.048 mm2), of which only 12.6% were T cells. There was no predominance of the 2a/T8 subset in nonrejecting biopsies. It is concluded that in patients receiving conventional immunosuppression, rejection is associated with an influx of T cells, most of which are 2a/T8-positive, into the cardiac allograft. In contrast, biopsies from patients on Cys contained large numbers of infiltrating leukocytes that did not appear to correlate with the histological assessment of rejection. However, in these patients, rejection was associated with an increase in the number of T cells with no consistent pattern of subset distribution. Biopsies from nontransplanted hearts contained few infiltrating leukocytes (31.5 +/- 9.4/0.048 mm2), and none of them were T cells.
Patients with moderate to severe hirsutism presenting over an 18-month period to an endocrine clinic were assessed by clinical evaluation and hormone measurements. Hair growth rate was estimated by a photographic technique and the severity of hirsutism graded using an objective scale. Of 43 patients, 9 had polycystic ovaries and the remainder were considered to have idiopathic hirsutism. The most severely affected group had significantly increased hair growth rates compared with less clinically affected subjects, and 47% of this group showed objective features of virilization. However, apart from a significantly higher 24-hr urine 17-ketosteroid excretion all other hormonal patterns were not significantly different between severely and mildly affected patients. Serum levels of testosterone (T), sex hormone-binding globulin (SHBG), free T (calculated from T and SHBG values), and androstenedione (A) were abnormal in 44%, 51%, 60% and 60% of patients respectively, whereas plasma levels of the specific adrenal androgen DHAS were increased in 40% of patients. There was an overlap between patients with elevated hormone levels, although isolated elevation of T, A or DHAS were seen in 9%, 19% and 3% of patients respectively. In 19% of patients all serum androgen measurements were normal. Gonadotrophin levels were significantly lower in the more severely affected group. Thus androgen levels in patients with idiopathic hirsutism or polycystic ovaries, show considerable overlap with measurements in normal subjects, and elevated plasma androgens may be of adrenal (DHAS) or combined adrenal/ovarian (T, A) origin.