Although veterans experience better health relative to nonveterans around retirement age, they have poorer health than nonveterans among the oldest old. These findings inform our understanding of the veteran-nonveteran health-mortality paradox found in previous research and suggest a health crossover among veterans and nonveterans in later life.

Mural folliculitis is a consistent histologic lesion of canine demodicosis. The objective of this study was to describe the immunophenotype and to evaluate temporal changes in histologic lesions of demodicosis during the course of therapy. Five dogs with demodicosis were examined and biopsied biweekly for up to 14 weeks; three dogs were evaluated once only. Lymphocyte subsets infiltrating the lesions were quantified using immunohistochemistry to detect CD3, CD21, CD4, and CD8 antigens. Lymphocyte subsets in blood were analyzed from four dogs using flow cytometry. Mural folliculitis was always present during clinically active disease. In contrast, following resolution of clinical lesions, perifolliculitis and/or perifollicular granulomas were present but mural folliculitis was absent. Most lymphocytes infiltrating the follicular epithelium in lesions of mural folliculitis were CD3+ and CD8+; the ratio of CD4+ :CD8+ cells in this epithelium was 0.032. In contrast, the perifollicular dermis contained approximately equal numbers of CD4+ cells and CD8+ cells, with slightly fewer CD21+B cells. In peripheral blood, the ratio of CD4+:CD8+ lymphocytes was reduced and the percentage of CD8+ cells was increased in three of four dogs. These results indicate that mural folliculitis is a consistent lesion of clinically active canine demodicosis and is characterized by infiltration of the follicular epithelium by CD3+ CD8+ T lymphocytes. These lymphocytes are cytotoxic T cells, which may mediate the injury to the follicular epithelium in demodicosis. Alternatively, CD8+ T cells may play a role in resistance to Demodex canis infection or may represent a deleterious immune response in dogs that develop demodicosis.

Spontaneous adult-onset hypothyroidism, confirmed by a thyroid-stimulating hormone stimulation test, thyroid biopsy, and response to replacement therapy, is described in a female cat. Clinical signs consisted of profound apathy, hypothermia, poor hair growth, severe seborrhea sicca, and a puffy face. Cutaneous histological changes consisted of epidermal and follicular hyperkeratosis, teloginization of hairs, and dermal mucin deposition. There was no adnexal atrophy. Lymphocytic thyroiditis, equivalent to Hashimoto's thyroiditis, was shown by thyroid biopsy. Clinical signs rapidly responded to thyroxine replacement therapy. Glucose intolerance was coexistent with the hypothyroidism, but was not dramatically influenced by thyroxine therapy and probably was an independently occurring endocrinopathy. IN DOGS, hypothyroidism is the most common endocrinopathy and usually results from lymphocytic thyroiditis or thyroid atrophy.',2 Although lesions consistent with the development of hypothyroidism, including lymphocytic thyroiditis, have been reported from postmortem surveys of feline thyroid glands, no association with clinical disease has yet been d~c u m e n t e d .~.~ Clinical descriptions of feline spontaneous, adult-onset hypothyroidism in the veterinary literature have been confined to anecdotal reports.2 This report represents the first feline case of spontaneous, adult-onset hypothyroidism confirmed with a thyroid-stimulating hormone (TSH) stimulation test, thyroid biopsy, and response to replacement therapy. Concomitant glucose intolerance was also present, and was probably caused by an independently occurring endocrinopathy, because it did not significantly worsen with time or improve with thyroxine therapy. Materials and MethodsSerum thyroxine concentrations were measured using a radioimmunoassay procedure previously reported for use in cat^.^,^* Although this assay was not validated in our laboratory, it has been used extensively and validated by others.6 The TSH stimulation test was performed as follows: blood was collected in a serum tube for measurement of basal thyroxine (T4) concentration; 2.5 IU (0.4 IU/kg) TSHt was administered intramuscularly in the evening; and the post-TSH blood sample was collected 12 hours later. During exogenous thyroxine therapy, serum thyroxine concentrations were measured 8 to 12 hours after the last dose of thyroxine. Skin and thyroid biopsies were fixed in 10% neutral buffered formalin and processed by standard techniques for histological examination. Sections were stained with hematoxylin and eosin (skin and thyroid) and PAS-alcian blue (skin). An automated serum chemistry analyzer$ was used for serum chemistry analysis. The glucose tolerance test consisted of administration of 1 gm/kg 50% dextrose via a cephalic vein and blood samples collected from a jugular vein into a serum tube at preadministration, and 15, 30,45,60, and 120 minutes after glucose administration. The results were compared with reference values previously reported for cats.'* Tetra-Tab RIA, Organon Te...

In order to improve the diagnostic value of histopathologic examination of skin biopsy samples from dogs with atopic dermatitis and, perhaps, to identify any differences from the normal state that may predispose to this skin condition, we compared the anatomic and cellular morphology of skin from three standard sites in 21 normal and 15 atopic dogs. The standard sites were lateral neck, dorsal rump, and craniolateral abdomen. No differences between the two groups were found in the means of area or thickness of the stratum corneum or the remainder of the epidermis at any site. The area of sebaceous glands, but not apocrine sweat glands, was larger in the atopic group (P less than or equal to 0.05 for the lateral neck skin and P less than or equal to 0.1 for the dorsal rump skin). The mean number of non-metachromatic mononuclear cells in combined skin samples (126 microns 2) in atopic dogs (91.0 +/- 28.7) was significantly greater (P less than or equal to 0.01) than for the control normal dogs (65.3 +/- 19.3); the mean number of mast cells in atopic dogs (12.39 +/- 6.44) was similarly greater than in the controls (8.48 +/- 5.14; P less than or equal to 0.1). Eosinophils were significantly increased in atopic dog skin (P less than or equal to 0.01). with the mean for all three sites combined of 0.81 +/- 0.90 compared with a mean of 0.06 +/- 0.15 for normal dogs. Numbers of circulating blood eosinophils were not significantly different in the atopic and normal group.(ABSTRACT TRUNCATED AT 250 WORDS)

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