Estrogen deficiency aggravates insulin resistance and induces β-cell loss and diabetes in female New Zealand obese mice.

In several rodent strains such as the New Zealand Obese (NZO) mouse, the incidence of obesity-associated diabetes mellitus is much higher in males than in females. In the present study, we investigated the effects of ovariectomy on glucose homeostasis in female NZO mice in order to elucidate the mechanism of their diabetes resistance. NZO females were ovariectomized at the age of 4 weeks, received a high-fat diet and body weight, body fat, glucose and insulin tolerance were investigated in comparison to sham-operated mice.

Study of 5-hydroxymethylfurfural and its metabolite 5-sulfooxymethylfurfural on induction of colonic aberrant crypt foci in wild-type mice and transgenic mice expressing human sulfotransferases 1A1 and 1A2.

Scope: It was reported that the Maillard product 5-hydroxymethylfurfural (HMF) initiates and promotes aberrant crypt foci (ACF) in rat colon. We studied whether 5-sulfooxymethylfurfural (SMF), an electrophilic and mutagenic metabolite of HMF, is able to induce ACF in two murine models.

Methods And Results: In the first model, FVB/N mice received four intraperitoneal administrations of SMF (62.

Toxicity studies with 5-hydroxymethylfurfural and its metabolite 5-sulphooxymethylfurfural in wild-type mice and transgenic mice expressing human sulphotransferases 1A1 and 1A2.

5-Sulphooxymethylfurfural (SMF), an electrophilic metabolite of the abundant Maillard product 5-hydroxymethylfurfural (HMF), was intraperitoneally administered to FVB/N mice. At a dosage of 250 mg/kg, most animals died after 5-11 days due to massive damage to proximal tubules. At lower dosages, administered repeatedly, tubules also were the major target of toxicity, with regeneration and atypical hyperplasia occurring at later periods.

Indication of cocarcinogenic potential of chronic UMTS-modulated radiofrequency exposure in an ethylnitrosourea mouse model.

Purpose: To evaluate putative effects on tumour susceptibility in mice exposed to a UMTS (universal mobile telecommunications system) test signal for up to 24 months, commencing with embryo-fetal exposure.

Material And Methods: Animals were exposed to UMTS fields with intensities of 0, 4.8, and 48 W/m(2), the low-dose group (4.

Inflammation does not precede or accompany the induction of preneoplastic lesions in the colon of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine-fed rats.

Heterocyclic aromatic amines (HCAs) are formed in meat cooked at high temperatures for a long time or over an open flame. In this context 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), the most abundant HCA in cooked meat, has been suggested to be involved in colon and prostate carcinogenesis. In the latter case it has been reported that: (1) roughly 50% of Fischer F344 male rats treated with PhIP develop carcinomas in the ventral prostate lobe at 1 year of age; (2) inflammation precedes prostatic intraepithelial neoplasia in PhIP-fed rats; (3) inflammation specifically occurs in the ventral prostate lobe of PhIP-fed rats.

Matrix "blues": clue to a cranial thoracic mass in a dog.

A 5-year-old, intact male Italian Spinone dog was presented for progressive, severe dyspnea and coughing. Thoracic radiographs revealed a large mass in the right cranial thorax. Fine needle aspiration of the mass yielded a highly cellular sample containing dense clumps of oval to spindle-shaped mesenchymal cells with distinct intracytoplasmic vacuolation, consistent with lipoblasts and lipocytes.

Stimulation of the renin-angiotensin system in cats with hypertrophic cardiomyopathy.

Feline hypertrophic cardiomyopathy (HCM) is a disease of the ventricular myocardium, which may cause sudden death in cats, but neither the aetiology nor the effect on the circulation are well understood. Fourteen cats of either sex with naturally occurring HCM were studied post mortem. Their ages ranged from 9 months to 10 years with an average age of 4.

The distribution of renin in the segments of the renal arterial tree in cats: an immunohistochemical and ultrastructural study.

The intrarenal distribution of renin in the cat kidney was evaluated in a semi-quantitative immunocytochemical study using a cross-reacting antiserum directed against purified renin. In addition, the morphology of the juxtaglomerular apparatus was studied electron-microscopically. The majority of renin in the cat kidney was located in the distal portion of the afferent arteriole.

The renin-angiotensin system in cats with chronic renal failure.

The kidneys of eight male and two female cats with subacute (clinical illness 1-3 months) to chronic (clinical illness > 3 months) renal failure were examined histopathologically, electron microscopically and immunohistochemically. Semiquantitative morphometric data, obtained by measurement of the reninpositive portion of the afferent arteriole (RPP) and evaluation of the juxtaglomerular index (JGI), were compared with data from three healthy control cats. On the basis of the morphometric data, the animals with renal failure could be classified in three groups showing either a stimulated (group A), an unaltered (group B) or an inhibited (group C) renin-angiotensin system.

Hypothetical interpretation of the calcium paradox in renin secretion.

Most renin-positive cells of the preglomerular arteriole are intermediate in morphological appearence between smooth muscle cells and epithelioid cells. Intermediate cells contain, in addition to secretory granules, contractile proteins arranged as a sublemmal network. The paradoxical (inhibitory) role of calcium in renin secretion is explained, on the basis of these findings, by an increased tone of the sublemmal network; this might impair the preexocytotic access of renin granules to the cell membrane.