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Biomedical subjects

P May

Publications and source records attributed to P May.

At least 109 records · Page 6Linked to original sources

[Prevention of urinary calculi with thiazides and allopurinol. A long-term study].

In 30 cases of recurring urinary calcium oxalate and calcium phosphate calculi, renal or absorptive hypercalciuria or hyperuricemia, long term controls of serum and urine electrolytes were made under hydrochlorothiazide and allopurinol therapy. By differentiating the type of hypercalciuria it could be determined, if thiazide-therapy is indicated in renal hypercalciuria only or in the absorptive cases as well. Statistic comparison of the patients with - and without increased urinary sodium excretion solved the question whether high sodium excretion diminishes or abolishes the hypocalciuric thiazide effect. The frequency of stones before and after treatment supports the efficacy of thiazide prophylaxis.

Adult↗

Study of the functional activities concomitantly retained by the 115,000 Mr super T antigen, an evolutionary variant of simian virus 40 large T antigen expressed in transformed rat cells.

Simian virus 40 (SV40) transformed V 11 F 1 clone 1 subclone 7 rat cells (subclone 7) do not synthesize normal-size large T antigen (M(r), 90,000); instead, they produce a 115,000 M(r) super T antigen (115K super T antigen). This super T antigen is SV40 virus coded, and its synthesis results from rearrangement and amplification of integrated viral DNA sequences in subclone 7 (May et al., Nucleic Acids Res. 9:4111-4128, 1981). In this study the functional activities of 115K super T antigen were compared with the functional activities of SV40 large T antigen. Transfection experiments were performed with (i) cosmid SVE 5 Kb and plasmid pSVsT, both containing the super T antigen gene and (ii) plasmids pSV1 and pSV40, both containing the large T antigen gene. Transfection of pSVsT DNA or SVE 5 Kb DNA into secondary cultures of rat kidney cells induced the formation of transformed cell foci with an efficiency that was about 50% of the efficiency of pSV1 DNA or pSV40 DNA. Concomitant with the transforming activity, two other activities were also retained by super T antigen, namely, the ability to enhance the level of host cellular protein p53 and the capacity to bind to p53. In contrast, pSVsT and SVE 5 Kb DNAs were markedly deficient in the capacity to support tsA58 DNA replication in CV1-P cells at a nonpermissive temperature (41 degrees C), as shown by cotransfection experiments. The yield of virus produced in these experiments was 400-fold less than the yield obtained in parallel experiments with pSV40 or pSV1. However, SVE 5 Kb and pSVsT have a functional SV40 replication origin, as shown by their efficient replication in COS 1 cells which provided functional large T antigen. Super T antigen also possesses a specific affinity for sequences of SV40 viral origin. Our results suggest that under certain conditions, evolutionary changes in T antigen take place and that these changes could be restricted to the phenotypic requirement of maintaining a structure that is able to induce cell transformation, to form a complex with p53, and to enhance the cellular level of p53. Therefore, there appears to be a close relationship among the activities of T antigen involved in transforming cells, in binding to p53, and in enhancing the p53 cellular level. Moreover, this set of activities appears to be separable from the replicative ability of T antigen, based on the observation that 115K super T antigen is markedly defective for initiating viral DNA synthesis.

Animals↗

Long-term observation of young cystinuric patients under ascorbic acid therapy.

Long-term results of ascorbic acid monotherapy in four young patients with cystine stone complaints are reported. The therapeutic program is based on the descriptions by Asper and Schmucki, who publicized the method for the first time in 1979. Clinical course observations, renal function checks as well as the excretion of cystine, uric acid and oxalic acid during ascorbic acid therapy of our patient pool will be discussed. Clinical observations made to date indicate that ascorbic acid therapy is a practical, inexpensive prophylaxis for cystine stone patients that is virtually free of side effects.

Adolescent↗

[Value of urine cytology in the diagnosis of tumors of the kidney pelvis].

Based on case report the value of urine cytology after renal pelvis lavage for the definite diagnosis of a renal pelvis carcinoma is demonstrated. The exact preoperative differential diagnosis permits a radical operative procedure without intraoperative tumor exposure decreasing the danger of spread of tumor. The simple and inexpensive technique should be applied in the urologic practice more often.

Cytodiagnosis↗

Mapping of the viral mRNA encoding a super-T antigen of 115,000 daltons expressed in simian virus 40-transformed rat cell lines.

Simian virus 40-transformed V11 F1 clone 1 subclone 7 rat cells produced a considerable amount of an elongated form of large-T antigen with an Mr of 115,000 (115K super-T antigen), but these cells did not produce detectable traces of normal-sized large-T antigen (86,000 daltons) (P. May, M. Kress, M. Lange, and E. May, Cold Spring Harbor Symp. Quant. Biol. 44:189-200, 1980). First, a comparison of the tryptic peptide fingerprints of 115K super-T and large-T antigens suggested that 115K super-T antigen is simian virus 40 coded and contains a duplication of amino acid sequences of large-T antigen. Second, from S1 mapping analysis of 115K super-T mRNA, performed with various restriction fragments of simian virus 40 DNA, it was concluded that super-T mRNA is a form of large-T mRNA containing a tandem duplication of the sequence extending from approximately 0.46 to 0.35 map unit. The duplicated sequence corresponded to that region of the simian virus 40 genome in which 12 of 13 tsA mutation sites are clustered (C. J. Lai and D. Nathans, Virology 66:70-81, 1975).

Animals↗

Ability of nonpermissive mouse cells to express a simian virus 40 late function(s).

Mouse cells are fully nonpermissive for simian virus 40 (SV40). Infection does not lead to detectable virus replication. In this report, it was shown, first, that spliced 16S and 19S SV40 late mRNA were present in cytoplasmic and polysomal polyadenylated acid+ RNA preparations from SV40-infected baby mouse kidney cells. The 16S and 19S SV40 late mRNA's produced in infected baby mouse kidney cells were identical to or similar to the 16S and 19S SV40 late mRNA's produced in permissive monkey cells as judged by their S1 mapping patterns performed with the late strand of HpaII-BamHI fragment B and by their sedimentation patterns in a sucrose gradient. It was also shown that the 16S late mRNA from infected baby mouse kidney cells could be translated into a polypeptide which was identical to or similar to virion protein VP1 in every aspect examined, including the patter of peptide mapping by limited proteolysis. Second, we reported that mouse kidney cells produced detectable, although low, levels of SV40 virion protein VP1, as shown by the sodium dodecyl sulfate-polyacrylamide gel autoradiogram of [35S]methionine-labeled proteins immunoprecipitated by a rabbit antiserum directed against SV40 virion proteins. Third, it was reported that infected baby mouse kidney cells produced late mRNA's either (i) when the infection was done at a restrictive temperature with the nonleaky tsA58 mutant or (ii) in cells treated with 100 microgram of cycloheximide per ml, in which large T antigen synthesis was inhibited by more than 99.9%. This suggested that large T antigen was not required for the synthesis of late mRNA in mouse cells.

Animals↗

Blunted prolactin response to hypoglycemia in patients with hypothalamic-pituitary disease and in subjects receiving estrogen.

The prolactin response to hypoglycemia was evaluated in 22 control subjects and 8 patients with hypothalamic-pituitary disease but normal basal serum prolactin levels. Eighteen of the 22 control subjects demonstrated at least a twofold prolactin rise in response to hypoglycemia. In contrast to the control subjects, none of the 8 patients demonstrated a prolactin response to hypoglycemia. This blunted prolactin response to hypoglycemia was the only endocrine abnormality in 3 of these 8 patients. In an attempt to better determine the sensitivity of the prolactin response to hypoglycemia as an index of early pituitary disease, the effect of a short course of estrogen on the prolactin response to hypoglycemia was examined. Estrogen was selected because of its known acute stimulatory effect on pituitary mitosis and chronic effects that lead to pituitary tumor formation in rodents. Accordingly, diethylstilbestrol (DES) 5 mg t.i.d. was administered orally to 6 normal men for 3 days, a period known to stimulate pituitary mitotic activity in rodents. Diethylstilbestrol treatment caused significant elevation of the baseline prolactin (8 +/- 2 versus 18 +/- 3 ng/ml, p less than 0.05); however, the prolactin response to hypoglycemia was blunted (8 +/- 2--30 +/- 10 ng/ml, p less than 0.05, before DES; 18 +/- 3--20 +/- 5 ng/ml after DES, p greater than 0.05). This estrogen-induced blunted prolactin response to hypoglycemia resembled the blunted prolactin response to hypoglycemia found in patients with hypothalamic-pituitary disease.

Acromegaly↗

A Navajo health consumer survey.

The findings of a health consumer survey of 309 Navajo families in three areas of the Navajo Reservation are reported. The survey shows that access to facilities and lack of safe water and sanitary supplies are continuing problems for these families. The families show consistent use of Indian Health Service providers, particularly nurses, pharmacists and physicians, as well as traditional Navajo medicine practitioners. Only incidental utilization of private medical services is reported. Extended waiting times and translation from English to Navajo are major concerns in their contacts with providers. A surprisingly high availability of third-party insurance is noted. Comparisons are made between this data base and selected national and regional surveys, and with family surveys from other groups assumed to be disadvantaged in obtaining health care. The comparisons indicate somewhat lower utilization rates and more problems in access to care for this Navajo sample. The discussion suggests that attitudes regarding free health care eventually may be a factor for Navajo people and other groups, that cultural considerations are often ignored or accepted as truisms in delivering care, and that the Navajo Reservation may serve as a unique microcosm of health care in the U.S.

Adolescent↗

Effects of ethidium bromide on the production of ribosomal RNA in cultured mouse cells.

A treatment of primary mouse kidney cell cultures with 5 microM Ethidium Bromide (Eth Br) reduces the transcription of nuclear-coded genes and especially of ribosomal RNA genes. This effect was consistently observed when comparing drug-treated and control cells for (i), the incorporation of 3H uridine into total nuclear and B RNA polymerases as determined in isolated nuclei. It became more pronounced with exposure time; however, after removal of the drug, there was a progressive recovery of RNA synthesis culminating in the complete reversal of the drug effect. That this effect is probably not due only to the suppression of mitochondrial protein synthesis by the drug, is shown by a comparative study of the effects of chloramphenicol treatment. In addition, in the cytoplasm Eth Br depresses the labeling of 28 S rRNA more than that of 18 S whereas no abnormal accumulation of 28 S rRNA is observed in the nucleus. It is suggested that Eth Br may affect either the stability of the 28 S rRNA or its rate of formation from the 32 S precursor.

Animals↗

Simian virus 40-transformed cells express new species of proteins precipitable by anti-simian virus 40 tumor serum.

In addition to the virus-coded large-T and small-t antigens, two new classes of proteins were immunoprecipitated by anti-simian virus 40 (SV40) tumor serum from extracts of various SV40-transformed cell lines. These were as follows: (i) proteins (termed "super-T proteins") with an Mr higher than that of large-T antigen (86,000), which were found in many SV40-transformed cell lines derived from mouse and rat cells (super-T proteins and large-T antigen appeared to have closely related structures as judged by the Chromobead elution patterns of their methionine-labeled tryptic peptides); (ii) proteins (termed "55K proteins") with an Mr ranging from 50,000 to 60,000, which were present in all SV40-transformed cell lines examined so far, including those obtained by chromosome-mediated gene transfer. The 55K proteins were not structurally related to large-T antigens, as judged by the Chromobead elution patterns of their methionine-labeled tryptic peptides. Our data are compatible with the assumption that the 55K proteins are largely or totally cell coded.

Animals↗

Evidence for a thyrotropin inhibitory effect of histamine in man.

Because of certain side effects of cimetidine therapy which may be hormonally mediated (e.g. gynecomastia), there has been recent interest in the possible endocrine effects of this H2 histamine receptor-blocking agent used in the treatment of peptic ulcer disease. Accordingly, the effect of chronic cimetidine therapy on anterior pituitary function was examined in 12 adult men with mild peptic ulcer disease. TRH and insulin-hypolycemic stimulation tests were performed by standard methods. Serum for TSH and PRL RIA was obtained after TRH; serum for GH, cortisol, and PRL RIA was obtained after insulin-induced hypoglycemia. In addition, serum for LH, FSH, testosterone, and PRL was obtained every 4 h for 24 h. After these baseline studies, 300 mg cimetidine were administered orally 4 times a day for 4--8 weeks and the studies were repeated as before. Chronic treatment with cimetidine caused a significant increase in the peak TSH response to TRH at 30 min (mean peak TSH value before cimetidine, 7.0 microU/ml; after cimetidine, 10.2 microU/ml; P less than 0.05) as well as a significant increase in the TSH area under the curve. There was no statistically significant effect of cimetidine on basal TSH or basal or stimulated PRL secretion. Cimetidine had no effect on the GH, PRL, or cortisol response to insulin-induced hypolycemia or the 24-h secretion of LH, FSH, testosterone, or PRL.

Adult↗