Virulence of coagulase-deficient mutants of Staphylococcus aureus in experimental endocarditis

A sensitive rat endocarditis model which employed relatively small inocula (< or = 10(4) cfu) was used to examine the role of coagulase in the pathogenesis of infection. Rats with indwelling, intracardiac catheters were challenged intravenously with three strains of Staphylococcus aureus. The virulence of a coagulase-positive parental strain DU5808 was compared in terms of its ID50 for resected vegetations and catheters to that of two coagulase-negative mutant strains (DU5809 and DU5814) which had undergone site-specific mutagenesis. Confidence intervals of infection rates were calculated and comparisons were performed of weights of infected vegetations, bacterial concentrations in vegetations and early mortality rates. From these virulence parameters, it was concluded that there were no differences in virulence among the three strains. The results from this investigation support the previous findings in mouse models of subcutaneous infection and mastitis, which indicated that coagulase production by S. aureus does not appear to function as a virulence factor. Together, these data refute the longheld belief that coagulase is important in the pathogenesis of infection and indicate that other markers of virulence must be operative in diseases caused by the enduring pathogen S. aureus.

Cytopathology in the post mortem room

AIM

To demonstrate the role of cytopathology in examining tumours found at post mortem examination.

METHODS

Tumour deposits were found in 25 hospital necropsies. Cytological diagnosis made at the time of necropsy was compared with subsequent paraffin wax embedded histological sections.

RESULTS

In 19 out of 20 cases with no previous histological diagnosis, cytology at the time of necropsy provided rapid and accurate assessment of tumour type. Subsequent histological examination of formalin fixed material merely refined the diagnosis in some cases. In the remaining five cases in which tumour type was known, cytological examination of deposits found at necropsy provided extra information that was useful for compiling a provisional report.

CONCLUSIONS

Rapid cytological examination of tumours found during post mortem examinations provides accurate relevant information which can be used to produce a more comprehensive provisional necropsy report. The technique has advantages over frozen section histology and can provide useful cytological experience for histopathology trainees.

The predictors of persistence of depression in primary care

164 patients in primary care who were recognized as depressed by their physicians and started on antidepressants were interviewed at 1 and 4 months after initiation of treatment. Ten factors hypothesized to be related to persistence of depressive symptoms were entered into a multivariate analysis to determine predictors of persistence of affective symptoms. Patients with minor depression were significantly older, more likely to be married or cohabitating, more likely to have serious medical illness, and had significantly less comorbid panic disorder, recurrent depression and lower neuroticism scores compared to patients with major depression. Approximately half of the patients in this primary care sample with major depression and one-third of those with minor depression were still distressed at 4 months, although few met criteria for major depression. Severity of depression and high neuroticism scores were the best predictors of persistent depressive symptoms.

Flow cytometric DNA ploidy analysis in canine transitional cell carcinoma of urinary bladders

Flow cytometric analysis of DNA ploidy was performed on 51 formalin-fixed, paraffin-embedded samples of canine transitional cell carcinoma of the urinary bladder. The DNA ploidy data obtained were compared to several clinicopathologic features. In addition, the DNA ploidy of 15 hyperplastic/inflamed and 8 normal canine urinary bladders was measured. Forty-three of the 51 neoplastic samples had interpretable DNA histograms. DNA aneuploidy was found in 34/43 (79%) of the transitional cell carcinoma samples. Of the 34 aneuploid neoplasms, 16 (47%) were hyperdiploid, 17 (50%) were tetraploid, and 1 (3%) was hypertetraploid. No significant correlation was found between the presence of DNA aneuploidy and the growth pattern, histologic grade, clinical stage, or individual morphologic features of this neoplasm. Additionally, the DNA ploidy was not related to the sex, age, or survival time of dogs with transitional cell carcinoma. All of the normal and all but one of the hyperplastic/inflamed urinary bladders were diploid. The results from this study demonstrated that DNA ploidy can be measured from paraffin-embedded canine samples by flow cytometry, a majority of the canine transitional cell carcinomas were aneuploid, and a significant correlation did not exist between the DNA ploidy and specific clinicopathologic features of this neoplasm.

Methodologic issues in randomized trials of liaison psychiatry in primary care

Most anxiety, depressive, and substance abuse disorders are treated exclusively in the primary care health system. However, recognition and treatment of these disorders in primary care is deficient. Psychopharmacologic and psychotherapeutic interventions have been developed and proven effective in randomized trials in specialty care. However, the results of successful trials of mental health interventions in specialty settings may not generalize to primary care settings because of epidemiologic differences in patients, differences in skills of providers, as well as differences in the very structure of care. The importance of the development of innovative randomized trials to improve recognition and treatment of mental illness in primary care is emphasized, as well as the methodologic problems inherent in carrying out these trials.

Comparison of image analysis and flow cytometric measurements of DNA content of canine transitional cell carcinomas

The DNA content of neoplasms is generally determined by flow cytometry, but quantitative microscopic image analysis is an alternative technique for DNA quantification. To compare these two methods, the DNA content of 31 paraffin-embedded canine transitional cell carcinomas was measured by flow cytometry and image analysis. Interpretable data were available for 26 samples by flow cytometry and 27 samples by image analysis. For 23 neoplasms with interpretable data by both methods, a good correlation (r = .80, P < .001) was obtained between the DNA indices determined by flow cytometry and image analysis. Concordance of DNA ploidy classification was reached in 21 samples; however, for 4 samples an aneuploid cell population, usually tetraploid, was identified by image analysis and not by flow cytometry. Two samples also had aneuploid peaks by flow cytometry and not by image analysis. Although a good correlation was seen between the measurement of DNA content of paraffin-embedded canine tissue by image analysis and flow cytometry, this study did demonstrate that aneuploid cell populations can be missed by both methods and that image analysis was better than flow cytometry in the detection of aneuploid cell populations, particularly tetraploid ones, in samples with excessive cellular debris.

Cyclosporine A induced colitis and acquired selective IgA deficiency in a patient with juvenile chronic arthritis

A 12-year-old girl with juvenile chronic arthritis was treated with cyclosporine A for recurrent uveitis. Two years later she presented with weight loss and diarrhea. Investigations suggested drug induced colitis. She improved after withdrawal of cyclosporine and her nonsteroidal antiinflammatory drug. Symptoms recurred on rechallenge with cyclosporine. She has developed a progressive selective IgA deficiency which persists despite cessation of cyclosporine.

The effect of beta-adrenoreceptor agonists and antagonists on fructose absorption in man

To explore the effect of beta-adrenoreceptor stimulation and blockade on the extraction of monosaccharide from the upper gut, we first established the malabsorption threshold in 26 normal volunteers using a series of test meals containing varying proportions of fructose and glucose. Incomplete small intestinal extraction and consequent arrival of carbohydrate into the caecum was identified by a rise in exhaled breath hydrogen concentration. The malabsorption threshold varied between individuals from 30 to 80 g fructose (median 40 g) but was reproducible within individuals, with 90% agreement of repeat studies. The malabsorption threshold for an individual was unrelated to body height (tau = 0.007, P > 0.05) or weight (tau = 0.003, P > 0.05) but correlated closely with time to onset of the breath hydrogen rise of a standard meal (tau = 0.70, P < 0.001). Administration of the beta-adrenoreceptor antagonist propranolol (160 mg) reduced the quantity of fructose required to exceed the malabsorption threshold from 45, 30-60 (median and range) to 40, 30-50 g (P = 0.03); administration of the beta-adrenoreceptor agonist isoprenaline (0.015 micrograms.kg/min) increased the quantity of fructose required to exceed the malabsorption threshold by 10 g (55 (50-90) g; P < 0.02). The effect of both drugs correlated closely with their transit effect (tau = 0.79, P < 0.01). A beta-adrenoreceptor mediated pathway thus appears to be capable of influencing the extraction of monosaccharide from the small intestine in normal subjects both under resting and stimulated conditions, probably acting via an effect on upper gastrointestinal motility.

An outbreak of echovirus type 4 infections and its implications for diagnosis and management in general practice

Altogether, 133 patients with Echovirus type 4 infection were studied. Presenting illnesses and reasons for referral to hospital were analyzed. The reason for admission was commonly concern about meningitis, but also an unexplained rash or sore throat. More research is needed in general practice in order to clearly elucidate the spectrum of disease caused by Echoviruses.

Fatty acid composition of adipose tissue in aged rats: effects of dietary restriction and exercise

Little is known about the long-term effects of diet restriction, exercise, and aging on the fatty acid composition of adipose tissue. To investigate these effects, male Wistar rats were placed in one of four experimental groups: 1) ad libitum fed, nonexercised; 2) ad libitum fed, exercised; 3) diet restriction, nonexercised; and 4) diet restriction, exercised. Exercise consisted of swimming on alternate days, and diet-restricted animals were fed every other day. Animals were assigned to one of the four treatment groups at weaning, and the fatty acid composition in the epididymal, perirenal, and inguinal fat depots were determined every 4 months from 12 to 28 months of age. All animals were fed the same diet so the relative percentage of fatty acids in the diet did not contribute to the changes observed in adipose tissue fatty acid composition. Regardless of treatment groups and fat depot, the concentration of saturated fatty acids in adipose tissue tended to decrease as body weight increased. Saturated fatty acid composition was greater in the diet-restricted than the ad libitum-fed groups. The saturated fatty acid concentration was different between the three fat depots (perirenal 27.8%, inguinal 24.7%, and epididymal 21.6%; P < 0.001). The linoleic acid content did not change with age in the epididymal or perirenal fat depot; however, the change was significant for the inguinal fat depot. Following a large decrease in inguinal linoleic concentration through 20 months, linoleic acid concentration increased in all treatments between 20 and 28 months. The results indicate that diet restriction, exercise, and aging have significant effects on adipose tissue fatty acid composition and these effects are different depending on the anatomical location of the adipose tissue depot.

Interpersonal behavior of preschizophrenic children: a study of home-movies

This study used an interpersonal coding scheme to compare the childhood behavior of adult-diagnosed schizophrenics and their nearest in age, normal sibling. Subjects consisted of 14 preschizophrenics (11 male and 3 female) and 14 sibling controls (8 male and 6 female) depicted in home movies between the ages of five and ten inclusive. Data were analyzed in two age groups: 5-7 vs. 8-10. Preschizophrenics were found to display more frequent negative affect between the ages of 5-7, but this difference disappeared in the 8-10 year age group. This finding is consistent with existing literature on affect development and represents the first directly observed evidence of developmental deviance in preschizophrenic subjects before the age of 11.

Cytokine production and surface antigen expression by peripheral blood mononuclear cells in postmenopausal osteoporosis

It was reported earlier that IL-1 production by cultured monocytes and the ratio of helper (CD4) to suppressor (CD8) lymphocytes in peripheral blood are different in osteoporotic compared to nonosteoporotic subjects. We examined these and several other parameters related to the biosynthetic activity and differentiation status of peripheral blood mononuclear cells (PBMC) in untreated osteoporotic postmenopausal women (age 65 +/- 7, n = 46), nonosteoporotic postmenopausal women (age 55 +/- 3, n = 20), and nonosteoporotic premenopausal women (age 37 +/- 7, n = 8), as defined by spine density. We found that unstimulated monocytes from osteoporotics did not produce detectable IL-1 beta as determined by ELISA. In addition, there were no significant differences between osteoporotics and nonosteoporotics in IL-1 beta or IFN-gamma production by PBMC stimulated with OKT3, a monoclonal antibody to the T cell-receptor complex. The proliferative response of lymphocytes to OKT3 was significantly less (p < 0.02) in osteoporotics compared to nonosteoporotic post- and premenopausal women; multiple-regression analysis, however, indicated that this difference was not due to bone density but to age. Flow cytometric analysis of PBMC revealed no difference between osteoporotics and nonosteoporotics in the distribution of 18 phenotypic subsets determined, including CD4- or CD8-positive lymphocytes or the ratio of CD4 to CD8 cells. Further, there was no correlation of the surface markers with bone density, the exceptions being the subsets expressing the CD3/CD56 and CD8/CD56 markers, which were inversely related to spine density in the osteoporotic women.(ABSTRACT TRUNCATED AT 250 WORDS)

Fumarylacetoacetase activity in cultured and non-cultured chorionic villus cells, and assay in two high-risk pregnancies

We describe further development of the fumarylacetoacetase (FAA) assay for the prenatal diagnosis of tyrosinaemia type 1 using chorionic villus sampling (CVS). We have established a reference range for FAA activity in cultured villus cells and have confirmed previously reported data on the FAA activity in uncultured chorionic villus cells. This should allow confirmation of results using CVS, without the need for further invasive procedures. We report the FAA enzyme stability at -70 degrees C, +4 degrees C, and at room temperature, and we have shown no obvious difference in enzyme activity with gestational age. We have analysed cultured and non-cultured CVS activity of FAA in two pregnancies at risk of tyrosinaemia type 1. In both, the fetus was designated unaffected, and these results were confirmed postnatally.

In situ Hybridization demonstrates the stability of mRNA in post-mortem rat tissues

In situ hybridization was used to detect messenger RNA (mRNA) in a variety of rat tissues which were fixed in formalin either immediately after death or after a 24 h period of storage at 5 degrees C. A synthetic polydeoxythymidine [poly d(T)] oligonucleotide probe was used to demonstrate polyadenylated [poly (A)] mRNA in the small intestine, pancreas, liver, cerebellum, and pituitary. Of these tissues, only the liver showed a small reproducible reduction in hybridization signal following delayed fixation. Synthetic oligonucleotide probes complementary to albumin and pro-opiomelanocortin (POMC) mRNAs were hybridized to liver and pituitary, respectively. There was no significant reduction in hybridization signal in post-mortem tissues. The results suggest that some mRNAs may be remarkably stable under certain post-mortem conditions and this should encourage the wider application of in situ hybridization techniques to post-mortem material.

The effect of alpha-1-adrenoreceptor agonist and antagonist administration on human upper gastrointestinal transit and motility

To explore the role of alpha-1-adrenoreceptor-mediated pathways on human upper gut motor function in vivo, we studied the effects of the alpha-1-agonist phenylephrine and the alpha-1-antagonist thymoxamine on oro-caecal transit and antroduodenal motor activity. Transit was measured using a standard exhaled-breath hydrogen method, and motility was measured by intraluminal manometry. Oro-caecal transit was unaffected by 80 mg thymoxamine [median 63 min (range 35-164 min) vs. control, 65 min (range 30-155 min), P greater than 0.1]. However, phenylephrine (2.4 micrograms/kg/min) consistently delayed oro-caecal transit time to 103 min (50-215 min), P greater than 0.005. Co-administration of thymoxamine abolished this phenylephrine-induced delay. The mean amplitude of antral postprandial contractions was reduced by phenylephrine from 29 (13-37) to 10 (3-13) mmHg (P less than 0.02). In contrast, neither the pattern nor the mean inter-contraction interval was altered. Responses to phenylephrine in the duodenum were similar to those in the antrum, with reduction in amplitude from 12 (3-18) to 6 (5-13) mmHg without alteration in the pattern or interval between contractions. Nutrient transit through the upper gut can thus be inhibited via activation of an alpha-1-adrenoreceptor-mediated pathway. Failure of alpha-1-antagonist administration to alter oro-caecal transit suggests that this pathway is not tonically active, and it is therefore unlikely to play a major role in nutrient passage under normal circumstances.