Lytic to temperate switching of viral communities.

Microbial viruses can control host abundances via density-dependent lytic predator-prey dynamics. Less clear is how temperate viruses, which coexist and replicate with their host, influence microbial communities. Here we show that virus-like particles are relatively less abundant at high host densities. This suggests suppressed lysis where established models predict lytic dynamics are favoured. Meta-analysis of published viral and microbial densities showed that this trend was widespread in diverse ecosystems ranging from soil to freshwater to human lungs. Experimental manipulations showed viral densities more consistent with temperate than lytic life cycles at increasing microbial abundance. An analysis of 24 coral reef viromes showed a relative increase in the abundance of hallmark genes encoded by temperate viruses with increased microbial abundance. Based on these four lines of evidence, we propose the Piggyback-the-Winner model wherein temperate dynamics become increasingly important in ecosystems with high microbial densities; thus 'more microbes, fewer viruses'.

Cutaneous phaeohyphomycosis due to Cladophialophora bantiana.

We present a case of cutaneous infection due to Cladophialophora bantiana, an agent of phaeohyphomycosis. The patient developed a nodule with pustule formation on the dorsum of the left hand; no trauma was reported. The lesion was successfully treated with itraconazole and surgical excision. Histopathologically, there was a blastomycosis-like tissue reaction pattern. Pigmented organisms were readily identified in tissue sections, and the cultural characteristics were those of Cladophialophora bantiana. This organism, known primarily for intracerebral involvement, can rarely produce cutaneous and subcutaneous infection. Immunosuppression should be suspected but is not always clinically apparent, as was demonstrated by our case.

Pentoxifylline increases retinal capillary blood flow velocity in patients with diabetes.

OBJECTIVE: The purpose of this study was to determine whether oral pentoxifylline would improve retinal microvascular hemodynamics and blood rheology in patients with diabetes. DESIGN: Patients were enrolled in a double-masked, placebo-controlled trial of pentoxifylline at 2000 mg/d. Retinal capillary blood velocity and leukocyte density, filterability, viscosity, and fibrinogen content were measured by the blue-field entoptic phenomenon simulation, filtration, rotational viscosimetry, and heat precipitation techniques, respectively, before, during, and after drug therapy. RESULTS: Treatment with pentoxifylline resulted in a 23.2%, 26.8%, and 37.8% increase in capillary blood flow velocity at 1, 2, and 3 months of therapy, respectively, with a return to pretreatment baseline levels 1 month after cessation of therapy. There were no apparent effects on the remaining variables during treatment. CONCLUSION: Pentoxifylline increases retinal capillary blood flow velocity in patients with diabetes.

Alterations in viscosity and filterability of whole blood and blood cell subpopulations in diabetic cats.

Capillary closure and venous dilatation occur early in diabetic retinopathy, and altered blood rheology may play a role. For example previous studies have shown leukocytes are less deformable, are more activated, and occlude retinal capillaries more often in diabetic subjects. The purpose of this study was to determine if rheologic changes developed in diabetic cats, a model in which we have documented retinal capillary basement membrane thickening, microaneurysms, and intraretinal hemorrhage characteristics of early diabetic retinopathy. Viscosity of blood, plasma and purified erythrocyte suspensions was measured by rotational viscometry and plasma fibrinogen content was determined by heat precipitation. Filterability of blood and purified erythrocyte, mononuclear leukocyte, and granulocyte suspensions was determined at constant flow, measuring the increase in pressure over 2 min relative to the pressure generated by buffer alone. Viscosity of whole blood and plasma, but not erythrocytes, was significantly elevated (P < 0.005) in the diabetic cats over normals at all shear rates studied (450, 225 and 90 sec-1). Furthermore, fibrinogen levels were significantly elevated in diabetic cats compared to normals (P < 0.004), and were positively correlated with the viscosity of whole blood and plasma. The filterability of mononuclear leukocytes and whole blood in diabetic cats was decreased 56% and 74% when compared to normals, P < 0.0006 and P < 0.025, respectively. In contrast, the filterability of granulocytes and erythrocytes was not significantly different between the two groups. These results suggest that the rheologic alterations in diabetes are numerous, and involve both cellular and plasma protein changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Internists' perceptions and performance in office practice.

Thirty-one internists in private practice chose items of care that they considered essential and likely to be recorded in the evaluation and management of diabetics, hypertensives, women with symptoms of dysuria or frequency, and patients requesting a general examination. Records of patients with these conditions, in those practices, were reviewed to determine which items of care were routinely performed and recorded. Overall, physical examination and laboratory evaluation items were more likely both to be considered essential and to be recorded than were history questions or management instructions. The lists of cure criteria and frequently performed components of the care process are presented for use by other peer review groups and for the interest of other practicing internists.

Tinea pedis in children.

Many children have dermatoses involving the feet. Such problems are often misdiagnosed as tinea pedis, which is relatively uncommon in this age group. On the other hand, tinea pedis should not be ignored as a diagnostic possibility just because of its infrequent occurrence. Six cases are reported to demonstrate that this diagnosis will be missed if appropriate laboratory studies are not done as a part of the evaluation of these dermatoses.