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Biomedical subjects

R Nicholson

Publications and source records attributed to R Nicholson.

At least 55 records · Page 3Linked to original sources
PubMed1976

GPC diesterase activity in human endometrial secretion. (Its variations under the action of estrogens, clomiphene citrate, D-norgestrel (post-coital and low dose) and intrauterine device (IUD).)

Diesterase activity was studied in human uterine secretions of normal women and in those under treatment for sterility or contraception. Endometrial secretions were obtained from 78 patients and the material divided into four groups: normal women, under different estrogens; with D-Norgestrel treatment (daily and post-coital) and patients with IUD Lippes D. The mean concentration of free choline delivered by the GPC diesterase in the normal group was 777 +/- 128 mug/ml (SD 286). Under hormonal treatment an increase of diesterase activity was observed. D-Norgestrel post-coital produced a fall of the enzymatic activity between 180 to 420 minutes. The uninterrupted use of D-Norgestrel (30 gammas daily) produced a loss of diesterase activity in 80% of cases studied. The use of IUD (Lippes D) did not modify the enzymatic activity in this group.

Clomiphene↗
PubMed1969

Oral contraceptives: long-term use produces fine structural changes in liver mitochondria.

Liver biopsies from two groups of women receiving oral contraceptives from 1 to 6 months and from 12 to 30 months, respectively, were examined by electron microscopy. The fine structure of the liver cells from the first group appeared normal, except for an increase in the amount of smooth endoplasmic reticulum. In the second group, however, there were many cases with striking changes-altered shape, increase in size, and presence of paracrystalline inclusions-in the mitochondria. No significant correlation between mitochondrial changes and alterations in liver function was detected.

Adult↗
PubMedDate not supplied

Effects of methyl xanthines upon the spermatozoa adenosinetriphosphate (ATP) concentration in normal semen.

The aim of the present study was to ascertain the effect of methyl xanthines upon the spermatozoa ATP concentration in normal semen in vitro. 26 normal semen were studied. The specimens were diluted after liquefaction with equal volume of Lopata's buffer or Lopata's buffer plus 1 or 6 mM either of caffeine or pentoxifylline. The samples of semen were incubated at room temperature during 90, 180 and 240 minutes before motility and ATP determination by the firefly luciferin-luciferase method. Significant variation was observed in sperm motility nevertheless variations in the ATP concentration was not induced by any of the methyl xanthines we used.

Adenosine Triphosphate↗
PubMedDate not supplied

Changes in sialic acid concentration in human saliva during the menstrual cycle.

Salivary sialic acid concentration was studied daily in 20 fertile women during the menstrual cycle. The Warren method was used and plasma LH and BBT were also determined. The sialic acid concentrations in saliva throughout the cycle showed a peak 4 or 5 days before the LH preovulation surge. This maximal peak showed a mean of 10.89 +/- 1.11 mg%. This method may be useful for predicting the pre- and postovulatory fertile period.

Adolescent↗