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Biomedical subjects

M Bates

Publications and source records attributed to M Bates.

At least 73 records · Page 4Linked to original sources
PubMed1980

The interaction of phenobarbital and other anticonvulsants with oral contraceptive steroid therapy.

In a group of 5 women on long-term anticonvulsant and oral contraceptive therapy, the plasma ethynylestradiol (EE) concentration on 50 microgram EE daily was 11.1 +/- 4.5 pg/ml. These values were at the lower end of the range found in normal women in this laboratory taking 30 microgram EE daily (6-190 pg/ml). Four women have been studied prospectively for 3 months, over 1 cycle before and 2 cycles during phenobarbital 30 mg b.i.d. therapy. Significant falls in the plasma EE concentration were seen in two women (from 104.8 +/- 13.4 to 37.7 +/- 2.0 pg/ml and from 125.6 +/- 23.8 to 34.8 +/- 6.7 pg/ml p less than 0.01) and breakthrough bleeding was seen in both women. No changes in plasma concentrations of follicle stimulating hormone, progesterone, norethindrone or norgestrel were seen. There was a significant increase in the sex hormone binding globulin capacity from 100.7 +/- 5.8 to 133.3 +/- 1.2 nmoles/1 (p less than 0.05). These changes are consistent with the known microsomal enzyme inducing effect of phenobarbital.

Adolescent↗
PubMed1980

Nonradioactive iodoantipyrine enhanced cranial computed tomography: preliminary observations.

Nonradioactive 4-iodoantipyrine, an iodinated indicator that freely diffuses across the blood-brain barrier, was serially imaged in vivo using computed tomography (CT). Prominent enhancement was immediately detected in the brain substance of the dog following the intracarotid injection of this contrast medium. An estimate was made of the brain:blood partition coefficient for 4-iodoantipyrine from the CT derived arterial and brain concentration of this iodinated marker. Practical applicability of this technique is limited unless an improved method for getting the 4-iodoantipyrine into solution can be developed. However, this study reinforces the concept that local cerebral blood flow and metabolism can be analyzed by diffusible tracers using CT.

Animals↗
PubMed1980

Comparison of oral cholecystopaques: iopronic acid vs. iopanoic acid.

A new oral cholecystopaque, iopronic acid, was compared to iopanoic acid. This was a double blind, randomized study of 260 subjects. A 4.5-G dose of iopronic acid produced a similar degree of gallbladder opacification as 3.0 g of iopanoic acid. Adverse reactions to the contrast media were generally mild, but were significantly less with iopronic acid. The present study is criticized because it was not designed to help the radiologist determine the better contrast medium under optimal clinical conditions.

Cholecystography↗
PubMed1978

Synthesis of phage M13 coat protein and its assembly into membranes in vitro.

The coat protein (gene 8 product) of coliphage M1O is an integral protein of the host cell membrane at all stages of virus infection. This protein, when made in a cell-free reaction, has been shown by others to have an additional NH2-terminal peptide region and is referred to as "procoat." It is initially not membrane-bound but, upon exposure to Escherichia coli membrane vesicles or to liposomes prepared from E. coli lipids, it assembles into the bilayer in an integral fashion. Much of this protein is shown to be exposed on the inner surface of the liposome. We suggest that refolding of procoat as it encounters the bilayer is sufficient to transport large segments of the peptide chain through the apolar hydrocarbon core.

Cell-Free System↗
PubMed1977

Abnormalities of circulating 25-OH vitamin D after jejunal-lleal bypass for obesity: evidence of an adaptive response.

Circulating levels of 25-OH vitamin D were measured in 44 patients who had undergone small intestinal bypass for obesity. Sixty-one percent had low circulating levels of the metabolite, which tended to normalize with time. This adaptive response also occurred for circulating total calcium, magnesium, albumin, and alkaline phosphatase. Serum concentrations of 25-OH vitamin D were directly related to total serum calcium and albumin. Impaired intestinal absorption of 25-OH vitamin D was seen in two patients. Following correction of total serum calcium for attendant hypoalbuminemia, 27% of patients remained hypocalcemic. The bone densities of two of 32 patients were low. In addition, skeletal biopsies of three of six patients were abnormal. It is concluded that small intestinal bypass results in at least transient deficits of circulating 25-OH vitamin D. As this operation may be associated with abnormal bone morphology, clinically significant skeletal disease may become apparent with long-term follow-up.

Adolescent↗
PubMed1976

Calcifediol in chronic renal insufficiency. Skeletal response.

Quantitative histology of thin, nondecalcified sections was performed on sequential bone biopsy specimens from five patients undergoing long-term hemodialysis and treated with calcifediol (25-hydroxycholecalciferol) for periods of three to nine months. With increase of intestinal absorption of calcium and decline of circulating immunoreactive parathyroid hormone and alkaline phosphatase, the bones of each patient exhibited striking histological improvement. The group as a whole showed statistically significant decreases in osteoclast number and in the percentages of osteoid surface covered by active osteoblasts. Marrow fibrosis was either eliminated or strikingly decreased in each patient. Osteoid volume significantly declined in four of five patients. In patients with osteitis fibrosa as the predominant histological lesion, calcifediol therapy resulted in decreased calcification front activity. Increased activity was the result when osteomalacia predominated.

Adult↗
PubMed1976

Improved microradiographic contrast for bone stain-historadiography.

Microradiographs of 5-micron sections of methyl methacrylate embedded undemineralized bone show poor resolution, but prestaining with silver nitrate increases the radioopacity of the calcified tissues to soft x-rays without masking regional differences in microscopic mineralization. Identical results are achieved using aqueous (pH 5.8 and 7.5) or ammoniacal solutions (pH 7.9). Atomic absorption spectrometry detected no loss of calcium from the sections during staining. Osteoid in plastic-embedded bone is not rendered radiopaque by this technique even after prolonged staining times (5 min-2 hr).

Autoradiography↗
PubMed1976

The effects of phosphate and vitamin D therapy on osteopenic, hypophosphatemic osteomalacia of childhood.

Two severely osteopenic adolescent males with clinical manifestations of adult onset hypophosphatemic osteomalacia were resistant respectively to physiological and pharmacological doses of vitamin D. Clinical improvement ensued following initiation of pharmacological doses of vitamin D and phosphate. Non-decalcified bone biopsies obtained before and during therapy exhibited correction of an isolated mineralization in the second. The response to treatment was reflected in striking changes in tetracycline-labelled calcification fronts in both patients.

Bone Regeneration↗
PubMed1975

The influence of testosterone on the synthesis and degradation rate of various RNA species in the mouse kidney.

1. The effect of a daily injection of testosterone on the in vivo rate of RNA synthesis and degradation in the kidney of castrated mice was determined. 2. Following the administration of testosterone there was a progressive increase in kidney weight, RNA and protein content in the castrated mouse kidney. 3. The rates of synthesis were calculated from the measured incorporation of radioactivity into various RNA species and acid-soluble nucleotides. The kidney RNA was labelled by the injection of a single dose of [5-3H] orotic acid. When the incorporation into ribosomal RNA was at the maximum (48 h), one group of mice was injected with testosterone (100 mug/day/20 g body weight) and the other served as the control. 4. The rates of synthesis and the turnover time were calculated on the basis of the half-life and the rate of decrease of specific radioactivity of RNA. The rates obtained were high in the first 5 days following hormone administration and then slowed down. 5. The results suggest that testosterone changes the rate of synthesis, not the rate of degradation of the mouse kidney RNA. This is consistent with the higher activity of RNA polymerase in testosterone-treated mice as previously observed and described (Avdalović, N. and Kochakian, C.D. (1969) Biochim. Biophys. Acta 183, 382-393; Avdalović, N. (1970) Biochem. J. 119, 331-338).

Animals↗
PubMed1975

Hiatus hernia.

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Hernia, Diaphragmatic↗