Biomedical subjects
L Roberts
Publications and source records attributed to L Roberts.
Experimental reproduction of porcine intestinal adenomatosis and necrotic enteritis.
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Location of the ss--mutation of bacteriophage T7 in genes 10, the structural gene for the major capsid protein.
T7+ phage are unable to plate on a strain of Shigella sonnei D2 371-48. Spontaneous phage mutants arise (ss--mutants) that are able to plate on this strain of Shigella. We have shown by complementation studies and genetic crosses that the ss--mutation maps in gene 10, the structural gene for the major protein of the capsid. This finding implies that the gene 10 protein may interact with a host protein during phage development and that the abortive infection of T7 observed in S. sonnei D2 371-48 with T7+ phage may be a defect in head morphogenesis. Our studies also reveal that various T7 strains commonly contain deletions in nonessential regions. T7 ss--mutants selected after growth of T7+ on Shigella D2 371-48 often acquire a deletion in the 0.7 gene that is not necessary for the ss--phenotype. Finally, we have found a new nonessential region of the T7 chromosome that is located between 33 and 35.5% of the T7 genome length.
The effect of constant illumination on the circadian rhythms of plasma thyrotropin and corticosterone and on the estrous cycle in the rat.
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The surface antigens of Campylobacter sputorum subspecies mucosalis.
Campylobacter sputorum subsp mucosalis is the vibrio associated with a group of porcine enteropathies in which it is believed the primary lesion is that of adenomatosis. The surface antigens of mucosalis were investigated and individual factor sera were produced; these were used to examine a range of field strains from adenomatosis, necrotic enteritis, regional ileitis and proliferative haemorrhagic enteropathy. Neither these not sequential isolants from the same farm showed any distinctive antigenic pattern and it is suggested that changes in the surface antigens take place during the intracellular existence of the organism.
Porcine intestinal adenomatosis associated with serologically distinct Campylobacter sputorum subspecies mucosalis.
A variant of Campylobacter sputorum subspecies mucosalis which is serologically distinct from all strains previously examined is described. It has been isolated from cases of porcine intestinal adenomatosis and necrotic enteritis and in all other characteristics conforms to the description of mucosalis.
Has psychiatry come in from the cold?
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The scapegoat.
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Inhibition of muscle cell development in culture by cells from spinal cord due to production of low molecular weight factor.
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Studies on Campylobacter sputorum subspecies Mucosalis.
Catalase-negative vibrios can be isolated in large numbers from the affected intestinal mucosa of pigs suffering from a range of porcine enteropathies in which the mucosa has an adenomatous component. These vibrios cannot be distinguished from strains of Campylobacter sputorum subsp. mucosalis. The resemblance between these bacteria strengthens the case already made on morphological evidence that these enteropathies have a common origin. Catalase-negative vibrios have also been isolated from the mouth and faeces of pigs. Some of these conform to the criteria established for the mucosalis subspecies but others can be differentiated from it. An antigenic analysis shows that strains of the mucosalis subspecies are closely related antigenically, but that differences may allow separation of strains.
Racial distribution of alpha1-antitrypsin variants among junior high school students.
A survey of alpha1-antitrypsin phenotypes and serum trypsin inhibitory capacities was performed in 1,841 seventh grade junior high school students. Antitrypsin deficiency states were detected only in white subjects (3.04) per cent) and not in 461 subjects of other races or of Mexican origin. A screening level of serum trypsin inhibitory capacity at 75 per cent of normal or less included all of the deficient phenotypes, but phenotyping was necessary to eliminate a small percentage of normal and unimportant variant phenotypes from this group. It is suggested that future programs for detecting antitrypsin deficiency and for counseling students who are genetically prone to develop pulmonary emphysema be aimed primarily at white populations.
Trends in hospital versus community treatment of mental illness: a Texas example.
The authors present statistics from Harris County, Tex., that indicate community psychiatry is making progress toward its goals of decreasing inpatient hospitalization and increasing services to the community. At the present ratio of services, a 30%-40% increase in outpatient services could theoretically eliminate the inpatient system. The authors stress the fact that inpatient facilities are still vital and offer directives for the future roles of the hospital and of community psychiatry.
Synovial osteochondromatosis involving the elbow.
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Negotiating a union contract in a Visiting Nurse Association.
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Isolation of Campylobacter sputorum subsp mucosalis from oral cavity of pigs.
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South East: the care of psychogeriatric patients.
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Myoglobinemia following acute myocardial infarction.
Myoglobin was identified in the serum of 11 of 21 patients after myocardial infarction by a sensitive specific complement fixation technic. This method allowed detection of as little as 0.03 mug of myoglobin. The assay tended to underestimate small concentrations of myoglobin due to serum interference. Myoglobinuria occurred with myoglobinemia but did not reflect the level of myoglobinemia or the duration of elevated serum levels. Larger amounts of myoglobin, 0.4 mug/ml or greater, were found in patients with severe infarctions, three of four of whom died as a result of this illness.
Nyctohemeral and sex-related variations in plasma thyrotropin, thyroxine and triiodothyronine.
TSH, T4, and T3 were measured by radioimmunoassay in plasma samples obtained from 77 young adult male and 114 female rats fed a Purina high-iodine diet and maintained in an isolated room, 2-4/cage, at 24 +/- 1 C with light from 0600-1800 h. In one experiment, 7 male and 7 female rats were decapitated every 3 h for 30 consecutive h and trunk blood was collected. There was a clear nyctohemeral rhythm of plasma TSH in both sexes characterized by a zenith at 1200 h and a nadir between 1800 and 2100 h. The plasma TSH cycle was approximately 180 degrees out of phase and negatively correlated (P less than .05) with that of plasma corticosterone (B) in both sexes. Although glucocorticoids have been reported to suppress TSH secretion, there was no causal relationship between plasma B and TSH in our experiments since the TSH cycles were normal in chronically adrenalectomized rats. Normal TSH cyclicity was not observed in severely iodine-deficient rats with extremely high plasma TSH levels although the nyctohemeral B rhythm was normal. Plasma TSH was approximately twice as high in males as in females (overall mean +/- SE: M = 149 +/- 11, F = 81 +/- 7 muU/ml, p less than 0.001). There was no significant difference (P greater than 0.05) in plasma TSH at different stages of the estrous cycle. Plasma T4 was slightly, but significantly, higher in males than females (overall mean +/- SE: M = 6.4 +/- 0.1, F = 6.0 +/- 0.1 mug/100 ml; P less than 0.001), while T3 was higher in females than in males (overall mean +/- SE: M = 69.5 +/- 1.7, F = 80.3 +/- 2.1 ng/100 ml; P less than 0.001). No significant nyctohemeral rhythm was observed in plasma T4 or T3 in either sex. These observations indicate that: 1) There is a nyctohemeral rhythm of plasma TSH which is independent of plasma B fluctuations and not associated with proportional changes in plasma thyroid hormones. 2) A sustained high rate of TSH secretion abolishes the normal nyctohemeral plasma TSH rhythm. 3) There are significant differences in plasma concentrations of TSH, T4, and T3 between male and female rats.