p21(WAF1) and transforming growth factor-alpha mediate dietary phosphate regulation of parathyroid cell growth.

BACKGROUND: The parathyroid (PT) hyperplasia induced by renal failure can be further enhanced by high dietary phosphate (P) or completely abolished by P restriction. To identify potential mechanisms mediating these opposing effects of dietary P on PT growth, this study first focused on p21(WAF1) (p21) because high P reduces while low P enhances serum 1,25-dihydroxyvitamin D, whose potent antiproliferative properties result from the induction of p21. In addition to reducing p21, high P-induced PT growth could result from increased PT expression of the growth promoter transforming growth factor-alpha (TGF-alpha), known to be elevated in hyperplastic and adenomatous human PT glands. METHODS: The time course for dietary P regulation of PT expression of TGF-alpha and p21 was assessed for seven days after 5/6 nephrectomy in rats and correlated with the degree of PT hyperplasia and secondary hyperparathyroidism. RESULTS: In P-restricted 5/6 nephrectomized rats, PT-p21 mRNA and protein increased by day 2, independent of changes in serum 1,25-dihydroxyvitamin D, and remained higher than in the high P counterparts for up to seven days. The PT hyperplasia of the high P group could not be attributed to a reduction of PT-p21 expression from normal control values. Instead, PT-TGF-alpha protein was higher in uremic rats compared with normal controls and increased further with high dietary P intake. PT levels of proliferating cell nuclear antigen (PCNA), an index of cell mitoses, correlated inversely with p21 and directly with TGF-alpha. Consistent with these findings, PT gland size and serum PT hormone levels, similar in both dietary groups at day 2, were higher in the high P group by day 5. Induction of p21 by low P and of TGF-alpha by high P was specific for the PT glands. Dietary P had no effect either on intestinal growth or p21 or TGF-alpha protein content. CONCLUSIONS: These findings suggest that low P induction of p21 could prevent PT hyperplasia in early uremia, whereas high P enhancement of TGF-alpha may function as an autocrine signal to stimulate growth further.

[The results of a seroepidemiologic study of Newcastle dysentery]. / Rezul'taty seroépidemiologicheskogo izucheniia dizenterii N'iukasla.

Differences in the monthly distribution in the number of seropositive individuals among children and adults in years with different intensity of the epidemic process have been revealed. Immunity in cases of dysentery caused by S. newcastle reflects the yearly and seasonal activation of the epidemic process in this Shigella infection both in children and adults, the seroconversion characteristics observed in the year of a high morbidity level being a more objective criterion indicating the beginning of the activation of the epidemic process in dysentery caused by S. newcastle in comparison with the commonly registered morbidity level.

[The main trends in a diphtheria epidemic process and the potentials for its elimination in a large city]. / Osnovnye tendentsii épidemicheskogo protsessa difterii i vozmozhnosti ee likvidatsii v usloviiakh krupnogo goroda.

In recent years the tendency towards the activation of the epidemic process of diphtheria, i.e. the appearance of cases of diphtheria simultaneously with the increased levels of circulation of toxigenic and nontoxigenic Corynebacterium diphtheriae and with antitoxic immunity characteristics in children and adults constantly remaining low, has been registered. For the effective control of diphtheria, the profound study of such problems as bacterial carriership, antibacterial immunity and the development of supplementary means of specific prophylaxis is necessary.

[Seasonality of Sonne dysentery among organized and unorganized groups of children in years with different morbidity levels]. / Sezonnost' dizenterii Zonne sredi organizovannykh i neorganizovannykh detei v gody s raznymi urovniami zabolevaemosti.

Differences in the monthly distribution of morbidity in Sonne dysentery among children of preschool age in children's institutions and among those not attending such institutions have been revealed. In years characterized by a high morbidity level, the epidemic process develops simultaneously among all children with some prevalence in its activity being observed from January to August among children not attending children's institutions and from September to December among institutionalized children. In years characterized by a low morbidity level, the rise of morbidity among children aged up to 3 years, both seasonal and not connected with the season (in January), is determined by the rise of morbidity among those children who attend children's institutions, while among noninstitutionalized children aged 4-6 years the seasonal rise of morbidity begins and becomes manifest earlier.

[Risk factors in the epidemiology of dysentery]. / Faktory riska v épidemiologii dizenterii.

The general tendency of a decrease in the morbidity rates of dysentery induced by Shigella sonnei and Shigella flexneri (separately) from Monday to the end of the week (Saturday-Sunday) has been revealed, and at the same time the "infection risk" for both kinds of salmonellosis has been found to fall on the last days of the week (Friday-Sunday).

[Monthly dynamics of the antitoxic immunity against diphtheria and tetanus and of normal antibodies to fraction I of the plague microbe in adults]. / Pomesiachnaia dinamika antitoksicheskogo immuniteta protiv difterii i stolbniaka i normal'nykh antitel k fraktsii I chumnogo mikroba u vzrosylkh.

Monthly characteristics of antitoxic immunity to diphtheria and tetanus toxoids in 3,334 adults in Ryazan were determined. As a result, the following differences were established: the characteristics of antidiphtheria immunity were somewhat higher in the autumn-winter period and dropped to the minimal level in the winter-spring period; the maximal characteristics of antitetanus immunity clearly coincided with the hot season, its minimal characteristics with the cold season. For the first time the frequency and titers of normal antibodies to fraction I of Pasteurella pestis in humans were determined. Their monthly dynamics proved to be parallel to the curve indicating the characteristics of antitetanus immunity, but on a lower level: 1-10%. The presence of normal antibodies was accompanied by higher titers to tetanus toxoid, but not to diphtheria toxoid. According to the results of earlier studies, normal antibodies were shown to be the sign of homologous reactivity in inbred animals. Our data indicate that these antibodies can serve as the indirect sign of heterologous reactivity in humans.