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Biomedical subjects

J Robertson

Publications and source records attributed to J Robertson.

At least 253 records · Page 14Linked to original sources
PubMed1977

Humoral regulation of vitamin B12 absorption by pregnant mouse small intestine.

In vivo experiments in which pregnant mice were fed an oral dose of 40 ng of [57Co]B12 demonstrated that there was a progressive increase in B12 absorption in the 3rd week of pregnancy. The absorptive mechanism resembled that in nonpregnant animals on the grounds that the mechanism was saturable, and presumably intrinsic factor (IF) dependent, and that it was localized to the ileum. In vitro studies of IF-57Co B12 binding to ileal homogenates confirmed the requirement for IF. Studies in late pregnancy showed that IF-[57Co]B12 binding to ileal homogenates, expressed as nanograms of IF-[57Co]B12 bound per milligram of protein, was twice that of nonpregnant animals. When ileal homogenates were prepared from mice on days 20 to 21 of gestation, IF-[57Co]B12 binding fell to nonpregnant levels within 2 to 4 hr of hysterectomy. Hourly injections of serum from mice in late pregnancy, or from a female at the 37th week of gestation, maintained IF-B12 binding at levels reached during pregnancy, whereas nonpregnant serum was ineffective.

Animals↗
PubMed1976

Spermatogenesis in an infertile XYY man.

Testicular histology and meiosis has been studied in an XYY male patient identified at an infertility clinic. This man was found to have an XYY set chromosome complement in 15% of spermatogonial metaphases. There was no evidence of 2 Y chromosomes at diakinesis but there appeared to be a slight excess of sperm with a fluorescent Y body.

Adult↗
PubMed1976

A method to measure the adsorption of bile salts to vegetable fiber of differing water holding capacity.

Dietary vegetable fibers have physico-chemical properties which may influence their role in nutrition. A method is described which measures bile acid adsorption to fibers of differing water holding capacity. Such absorption studies are complicated by the water held in the fiber matrix which includes bile acid in solution. The entrapped solution gives some apparent adsorption but this can be removed by washing the fibers with water. This method differentiates between strong adsorption and reversible adsorption. This enables dietary vegetable fibers to be classified according to their bile acid absorption capacity which may be useful in selecting fibers for clinical trials.

Adsorption↗
PubMed1976

Pure partial trisomy for long arm of chromosome 9.

A case of a 4-year-old boy with trisomy of the long arm of chromosome 9 is described (46,XY, der (9), t (9;9) (q32;q12)). The trisomy is probably the result of a translocation of the long arm of the chromosome from one homologue to the other in a parental gonad. The clinical features of the child which include severe developmental retardation, bird-like facies, tapered fingers, and flexion contractures of the legs are similar to those of the few cases described of trisomy of the whole chromosome.

Abnormalities, Multiple↗
PubMed1976

A system for evaluating and treating chronic back disability.

Five methods of personality assessment are evaluated to provide guidance for the psychological treatment of patients with chronic back pain. Patient pain drawings, pentothal pain studies, stress score index, psychological testing with the Minnesota Multiphasic Personality Inventory (MMPI) and response to treatment challenge are used as measurements for evaluation. This evaluation gives the treating staff guidelines for individual treatment programs utilizing operant conditioning techniques. Using this approach, three fourths of the severely disabled patients seen have been successfully treated.

Back Pain↗
PubMed1976

Evidence for the presence of components of the alternative (properdin) pathway of complement activation in respiratory secretions.

Activation of the alternative complement pathway by respiratory secretory IgA was demonstrated by incubating purified, aggregated preparations of serum and secretory IgA with neat human serum. No depletion of the early components (C1-4) was observed, but 63 and 70% of C3-9, respectively, were consumed. The C3-9-consuming capacity of heat-aggregated nasal secretions from an IgA-deficient volunteer was compared with heat-aggregated nasal secretions from a normal volunteer known to have secretory IgA. The deficient secretions consumed C3-9, whereas the IgA deficient secretions did not. Reconstitution of the nasal secretions from the IgA-deficient volunteer with purified secretory IgA produced alternative pathway activation. Factor B of the alternative complement pathway was found to be present in 16 of 18 bronchoalveolar lavage samples (BALF) from normal volunteers. Simultaneous measurement of lavage and serum albumin and Factor B concentrations rendered it unlikely that Factor B was merely a transudative product from serum in half the samples but rather suggested that it may be a component of lower respiratory tract secretions. The presence of an intact alternative complement pathway in BALF was indicated by showing that cobra venom factor and endotoxin cleaved functionally pure human C3 when mixed with BALF, but had no effect on C3 in the absence of BALF.

Bronchi↗
PubMed1975

Maternal serum FDP and circulating fetal red cells throughout pregnancy. A longitudinal study.

The presence of fetal red cells in the maternal circulation and the serum FDP content of 73 women was followed serially throughout a normal pregnancy. There was a signigicant increase in the mean serum FDP levels in late pregnancy, which was due to episodic elevations occurring in approximately 65% of women. These transient elevations appeared to increase in frequency and severity as pregnancy progressed. There was also an increase in the number of occasions fetal red cells were detected in the maternal circulation in the later months of pregnancy, but his phenomenon did not appear to be associated in any way to the serum FDP elevations. It is concluded that the episodic rises in serum FDP occurring in normal pregnancy are not related to episodes of occult disseminated intravascular coagulation secondary to placental haemorrhage as was previously hypothesized. Their etiology and clinical significance remain unknown.

Adolescent↗
PubMed1975

Mycoplasma hominis: growth, reproduction, and isolation of small viable cells.

Improved methods for studying the growth of Mycoplasma hominis (ATCC 14027) have been developed, involving modified growth conditions and preparation of the organisms under minimally distorting conditions. Cells so prepared from batch cultures show relatively uniform exponential growth and appear to be dividing by binary fission; but pleomorphic forms appear upon further incubation. Similar behavior was demonstrated by another laboratory-adapted strain and by three clinical isolates, and therefore seems characteristic of the species. The pleomorphic populations contain small forms having diameters within the 100- to 250-nm size range reported for "elementary bodies." Such forms were isolated from this strain of M. hominis by sequential filtration using gravity alone, after cell aggregates were dispersed by Pronase treatment. Of the small bodies which traversed membranes of 220-nm pore size, a negligible number grew in liquid or on solid media, suggesting that these were not essential reproductive units in a life cycle, but involution forms due to growth in an altered environment.

Bacteriological Techniques↗
PubMed1975

Effect of preparatory techniques on the gross morphology of Mycoplasma hominis.

A method is presented whereby cells of Mycoplasma hominis can be prepared with minimal distortion for electron microscopy. After the addition of glutaraldehyde to broth cultures, incubation is continued for 1 h. The cells are then collected by centrifugation, washed in distilled water, and used for negative-contrast preparations.

Bacteriological Techniques↗