Biomedical subjects
Publications and source records attributed to G Phillips.
Two cases of infection due to Corynebacterium minutissimum are described. On the basis of biochemical tests the organisms were thought at first to be Corynebacterium jeikeium. Methods of distinguishing between these species and the role of C. minutissimum in the pathogenesis of erythrasma and other skin infections are discussed.
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As part of a large whole body disinfection (WBD) trial two small sub-groups of patients who showered preoperatively with either a 4% chlorhexidine (CHX: N = 29) or placebo (N =27) detergent were studied to assess intraoperative wound contamination. The groups were well matched for age, sex and length of surgery. A membrane filter contact technique was used for bacterial recovery from the wounds after the initial skin incision and before wound closure. The membrane filters were incubated aerobically on blood agar plates with a CHX neutralizer for 48 h at 37 degrees C and colonies were counted. The results show a significant difference, between the bacterial counts at the start and end of surgery in the CHX and placebo groups. There was no difference in bacterial counts at the start of surgery between the CHX and placebo groups. There was a significant difference in the bacterial counts at the end of surgery between the CHX and placebo groups. These results indicate that preoperative WBD with CHX reduces intraoperative wound contamination but the effect of this on postoperative wound sepsis rates awaits the results of a large WBD trial.
Bacterial skin flora were studied in two groups of patients having three showers with either a 4% chlorhexidine detergent solution (Group A, N = 57) or a placebo detergent (Group B, N = 58). Previous reports on the efficacy of chlorhexidine in decreasing bacterial counts on the skin were confirmed and the time taken to recolonization (median 5 days; range 1-10 days) was in broad agreement with previous reports. However, concern regarding the colonization of the skin of the patients in the chlorhexidine group by potential pathogens during the recolonization period appears unfounded as there was no significant difference in the incidence of non-resident skin flora between the chlorhexidine (17/57; 30%) and the placebo (14/58; 24%) groups. These non-residents are generally lost from the skin before discharge in the chlorhexidine group but nine patients in the placebo group had abnormal skin flora at discharge from hospital. All those patients tested after discharge had lost the non-resident flora within 2 weeks of discharge. The results of this study indicate that recolonization of the skin after whole body disinfection does not present a clinical problem.
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Evidence of activation of the clotting system in individuals with sickle cell anemia (SCA) has been observed by several investigators. It has been suggested that the clotting and fibrinolytic systems may play a role in the pathophysiology of vaso-occlusion in SCA. We reported previously evidence of abnormal fibrinolytic activity as reflected in decreased releasable tissue plasminogen activator (t-PA) using a functional assay. We have examined the mechanism of the decreased functional releasable t-PA in individuals with SCA. We studied 12 patients with respect to releasable t-PA, fast acting inhibitor to t-PA (or PAI-1), and immunoreactive or antigenic t-PA. These SCA individuals were at their baseline states and not taking medications known to interfere with the fibrinolytic or clotting systems. We found that the mean releasable t-PA for the SCA individuals was 0.01 IU/ml of plasma with a standard error of mean (SEM) of 0.01. The mean releasable t-PA of 118 healthy normal controls was 0.70 IU/ml with SEM 0.10 (P less than .001). The mean level of fast-acting inhibitor to t-PA in unoccluded circulation of the SCA patients' plasma was 16.5 IU/ml with SEM of 3.54. The mean plasma levels of fast-acting inhibitor to t-PA in 56 healthy controls was 2.56 IU/ml with SEM of 0.29 (P less than .0001). The SCA patients had a mean baseline t-PA antigen level of 5.98 ng/ml with SEM of 1.72. The mean level of t-PA antigen of 78 healthy controls using the same technique was 4.3 ng/ml with SEM of 2.7 (not significant). The mean baseline functional t-PA for SCA individuals was 0.15 IU/ml with SEM 0.01 and the mean baseline functional t-PA for 118 controls was 0.17 IU/ml with SEM 0.10. These data suggest that the mechanism of decreased releasable t-PA in sickle cell anemia is related to an elevation of fast-acting inhibitor to t-PA and that antigenically t-PA is present in normal quantities in the baseline plasma in this population.
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Herrnstein's matching equation was used to analyze drug effects on performance in random interval reinforcement schedules. Pimozide caused effects compatible with both motor and motivational impairments, in a 5-component multiple schedule, a 3-schedule 3-day cycle (ALT-3), and a 2-schedule 2-day cycle (ALT-2). However, at low doses, both sulpiride and SCH-23390, tested in the ALT-3 and ALT-2 procedures, caused effects compatible with selective motivational impairments. In experiments using the non-multiple schedules, motivational effects increased during the course of the experimental session, under all three drugs. The interpretation of "motor" and "motivational" deficits in the ALT-2 procedure was validated by experiments in which the response-force and deprivation level were systematically varied. The results support the view that dopamine may be involved in the maintenance of rewarded behaviour, but not differentially implicate the D1 or the D2 receptor subtype.
Two sets of experiments were carried out to compare the effects of fenfluramine and fluoxetine on consummatory and operant behaviour. In food-deprived rats allowed access to a 35% sucrose solution, an initial period of sucrose consumption was followed by a short period of grooming and exploratory behaviour, later superceded by resting. This "behavioural satiety sequence" was advanced by fluoxetine, but disrupted by dl-fenfluramine, which suppressed post-prandial resting, even at sub-anorectic doses. Fluoxetine also elicited resting behaviour following water drinking. However, this did not appear to be a non-specific sedative effect, since fluoxetine increased post-prandial grooming. In rats performing on random interval schedules of food reinforcement, fluoxetine caused proportionally greater decreases in responding on a reinforcement-lean schedule (RI-300s), as compared to a reinforcement-rich schedule (RI-7.5s); this effect is similar to that of a reduction in level of food deprivation. By contrast, fenfluramine reduced responding equally on both schedules. In both paradigms, the effects of fluoxetine were compatible with an increase in postprandial satiety, but the effects of fenfluramine were not.
In an initial experiment pimozide decreased preference for a weak sucrose solution but increased preference for a strong solution on the descending limb of the concentration-intake function. As these effects resemble those of dilution, we therefore investigated whether pimozide decreases the perceived intensity of sweet stimuli. Rats were trained to perform a conditional discrimination in a T-maze. A correct response was rewarded by access to a 10% sucrose solution; an incorrect response was punished by confinement in the non-rewarded arm. In the first part of this experiment the discriminative stimulus, located at the choice point of the T-maze, was either water or sucrose, initially a 10% solution, but reduced gradually to 0.0003%. In the second part of the experiment, the discriminative stimulus was either 1% sucrose or a weaker solution, which was initially 0.0001% then raised gradually to 0.5%. Performance fell below 75% accuracy at 0 versus 0.0012% and at 1% versus 0.1%. Pimozide (0.5 mg/kg) administered at these (and other) levels of difficulty decreased running speed but had no effect on discrimination accuracy. As pimozide did not affect either the threshold for sweetness perception or the discrimination of a just noticeable difference, the decreased responsiveness of neuroleptic-treated rats to sweet rewards cannot be explained by a change in the perception of sweetness.
Twenty-nine patients with leukemia were observed for the development of and recovery from oral herpes simplex virus (HSV) lesions. In patients with seropositive test results, lymphocyte and monocyte counts may provide a guide to predict the onset of HSV infections and to indicate when to institute acyclovir prophylaxis. When HSV developed, acyclovir was effective in preventing progression of the lesions, which did not resolve until white cell counts had recovered.
Oral ciprofloxacin in doses of 0.75 to 2 g daily for 8-16 (median 10) days was given as first-line treatment of 33 unselected episodes of CAPD-associated peritonitis in 20 patients. Treatment was well tolerated and effective, curing 25 episodes. Treatment was withdrawn in five episodes, four because of resistant organisms and in the other because of vomiting. Infection relapsed twice in one patient during follow-up and one patient had persistence of the infecting organism (Pseudomonas aeruginosa) despite clinical improvement. Plasma and dialysate ciprofloxacin levels ranged from 1 to 8 mg/l. Assay between days 2 and 4 of treatment indicated the ciprofloxacin steady state concentration. If this proves to be greater than 7 mg/l the dose may be reduced and if less than 2 mg/l the dose should be increased. Overall a single course of oral ciprofloxacin was 76% successful as a first-line treatment for CAPD-associated peritonitis, caused by a wide range of organisms.
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Solutions of ciprofloxacin were irradiated with different wavebands of ultraviolet and visible radiation and the antibiotic activity of the drug was determined against Escherichia coli. A wavelength dependent loss of antibiotic activity was found with maximal effect around 320 nm; no effect occurred with visible irradiation. The degree of the decrease in activity with longer wavelength ultraviolet (UVA) radiation was sufficient to indicate that human exposure to sunlight through window glass (greater than 320 nm) or UVA from tanning sunbeds may result in a significant reduction in both cutaneous and circulating levels of ciprofloxacin.
This study examined the relationship of pain drawings to somatization in patients with sickle cell disease (SCD). Sixty-nine adult patients with SCD completed a pain drawing in which they shaded in areas of the body in which they experienced pain and also completed the symptom checklist (SCL) 90-R as an index of psychological distress. Analysis of variance indicated that patients who were categorized as having pain drawings with sites inconsistent with expected SCD pain patterns had somatization scores in the clinically significant range. The results suggest that health care professionals who treat SCD patients need to consider pain patterns. In individuals with pain patterns atypical for SCD, the psychological status of the patient may need to be evaluated to facilitate optimal pain management.
Eighty opiate addicts who had been successfully withdrawn from drugs were followed up for a period of six months after leaving treatment. Variables which might have been expected to relate to subsequent abstinence or drug taking were regressed against measures of outcome. Two variables consistently emerged as predictors of outcome. The number of protective factors identified by the subject and a measure of confidence about being able to remain drug free were both related to frequency of drug use during the first two months after leaving treatment, to drug status at six months and to improvement during the six-month period. In addition, the length of previous periods of abstinence related to outcome at six months, as did time spent in treatment, though caution is urged in the interpretation of this latter effect. Although risk factors have been found to relate to relapse there was no relation between perceived risks and outcome. Also, the number of coping strategies identified at admission was only related to outcome during the immediate post-discharge period. The implications of these findings are discussed in terms of a model of relapse.
Fifty seven babies with ophthalmia neonatorum had conjunctival smears examined by microscopy and bacterial culture, and by immunofluorescence, to find out which was the best method of diagnosing chlamydial conjunctivitis. The positive (33%) and negative (70%) predictive values of microscopy and culture were too low for us to accept it as an adequate method of detecting the presence of Chlamydia trachomatis.