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Biomedical subjects

R T Jones

Publications and source records attributed to R T Jones.

At least 307 records · Page 17Linked to original sources
PubMed1976

Salmonellosis in calves due to lactose fermenting Salmonella typhimurium.

A lactose fermenting strain of Salmonella typhimurium was isolated from two calves which died during an outbreak of acute enteritis. The organism was biochemically typical in all other respects. In one calf, uncomplicated by treatment before death, the autopsy findings were those of a severe fibrinous enteritis which was reproduced in another calf dosed orally with culture. Attention is drawn to scattered reports of lactose fermenting salmonelle causing morbidity and mortality in calves and man.

Animals↗
PubMed1976

Multiple structural genes for the alpha chain of canine (Canis familiaris) hemoglobin.

There are two forms of the alpha chain of canine hemoglobin differing only at residue 130. One form (taualpha) contains threonine at this position, the other (Aalpha) contains alanine. Studies of two Labrador dog families strongly support the existance of multiple alpha-chain structural genes as the basis of the alpha-chain heterogeneity. There must be at least one gene locus for Talpha and one for Aalpha; the exact number of loci has not been determined. Two other dog breeds, the Basenji and the Beagle, also have both Talpha and Aalpha chains.

Alanine↗
PubMed1976

Characterization of hemoglobin Burke [beta 107 (G9) Gly replaced by Arg].

Hb Burke [beta 107 (G9) Gly replaced by Arg] was discovered in a young woman with hemolytic anemia. A substitution in this position has not been previously reported either in the human beta-chain or in any of the animal beta-chains so far sequenced. The abnormal hemoglobin shows heat instability and a lowered oxygen affinity. The substitution of a large charged arginine residue for the small glycine residue in the G helix next to a heme contact (Leu-106) may be responsible for these effects. Hb Burke is compared with five other hemoglobins having Gly-Arg substitutions in other parts of the molecule.

Adult↗
PubMed1976

Analysis of the potency of extracts of June grass pollen by their inhibitory capacities in the radioallergosorbent test.

The potencies of 11 commercial extracts of June grass pollen were analyzed by skin test end point titrations and compared to potencies as determined in vitro (1) by the radioallergosorbent test (RAST), (2) by Group I antigen content, and (3) by protein nitrogen units (PNU). RAST potencies were determined by the capacity of the extract to inhibit the binding of IgE antibody to solid-phase allergen, and they were expressed as the quantity of extract required for 50% inhibition of binding. Potencies determined by skin testing in 8 patients were significantly related among the various patients in 19 of 27 comparisons and showed differences of up to 95,000-fold in the strengths of the extracts. Estimation of potencies by RAST inhibition showed approximately a 100-fold difference among the extracts and in 5 of 8 cases these were significantly related to potencies measured by skin tests. Similarly, PNU determinations and Group I determinations were also significantly related to potencies by skin test titration in 5 of 8 and in 4 of 8 comparisons, respectively. Comparison of the geometric mean skin test potencies with RAST, PNU, and Group I potencies revealed that all were significantly related to skin test potencies although the correlation of RAST and skin potency was the highest. The results indicate that measurement of potency by RAST inhibition compares favorably with other in vitro measurements of potency. These results are compared with those of a prior study with extracts of short ragweed, and the reasons for the differences between the results in the two studies are discussed.

Absorption↗
PubMed1976

Studies on Alternaria allergens. II. Measurement of the relative potency of commercial Alternaria extracts by the direct RAST and by RAST inhibition.

The relative potency of 12 commercial Alternaria extracts was analyzed by end-point skin test titrations and compared to in vitro measurements of potency, including (1) the radioallergosorbent test (RAST) inhibition procedure; (2) the direct RAST procedure; and (3) the protein nitrogen unit (PNU) content. Potencies determined by skin testing 10 sensitive patients were strongly correlated among the various patients. Measurements of potency by both RAST inhibition and direct RAST assay were strongly correlated to potency as measured by skin testing. In contrast, neither the weight:volume nor the PNU content bore any relationship to allergenic potency as measured by skin testing or by either of the RAST procedures. Extracts differed by as much as 3,000-fold in allergen content by skin testing. Moreover, the extracts appeared to contain different allergenic determinants when tested by RAST inhibition. RAST inhibition offered several technical advantages over the direct RAST procedure, in that only one solid-phase RAST reagent was required, slopes of dose-response curves could be more easily compared, and a greater discrimination in allergenic potencies among extracts could be made. The RAST appears to offer an excellent method for measuring the potency of allergy extracts, pending the isolation and characterization of actual allergens.

Allergens↗
PubMed1976

The cross-reactivity of IgE antibodies with pollen allergens. II. Analyses of various species of ragweed and other fall weed pollens.

Although the antigenic composition of short ragweed pollen has been extensively investigated, very few studies have analyzed the allergenic cross-reactivity among various types of ragweed pollens. Using a serum pool from patients sensitive to short ragweed, we studied the cross-reactivity of IgE antibodies to six ragweeds by the radioallergosorbent test. Extracts were analyzed for their inhibitory activities with solid-phase allergens prepared from all of the ragweed pollens. Also, samples of serum were absorbed with the various solid-phase allergens and the reactivity of the remaining IgE antibodies was determined. Two patterns of reactivity were observed. Short, giant, western, and false ragweeds displayed comparable reactivity in both inhibition and absorption experiments. Slender and southern ragweed were considerably less active, indicating that they lacked allergenic groupings possessed by the other species. These same patterns of cross-reactivity were found using ragweed pollens from four commercial sources. Knowledge of these patterns of cross-allergenicity is of importance for diagnosis and treatment of sensitive patients as well as for in vitro standardization of extracts.

Absorption↗
PubMed1976

Aging changes in the human aortic valve in relation to dystrophic calcification.

To elucidate the pathogenesis of aging changes and their relation to age associated calcification, a morphological study of 27 human aortic valves was carried out. Nine valves were obtained from immediate autopsies and 18 valves from routine autopsies done within four hours after death. Calcium deposition was present deep in the zona fibrosa along a zone of lipid accumulation. Fibrocytes in the zona fibrosa showed predominant age associated changes, i.e., a massive accumulation of residual bodies in the cytoplasm probably derived from autophagic vacuoles. Light microscopic lipid accumulation corresponded with both intracellular accumulation of electron dense spherules and membranous vesicles derived from degenerate fibrocytes. Calcium deposition in various stages, including needle shaped hydroxyapatite crystals, was seen in close association with these cellular degradation products rather than collagen or elastic fibers. Dystrophic calcification in the aortic valve appears to result from cellular aging and death followed by petrification of cellular degradation products, which may progress to calcific aortic stenosis.

Adolescent↗
PubMed1976

Post-traumatic hepatic dysfunction as a major etiology in post-traumatic jaundice.

Thirty-eight patients who had sustained acute trauma, profound hemorrhagic shock, and massive transfusion were studied prospectively to determine the predominant etiologic factors in the development of post-traumatic jaundice. An analysis of clinical and biochemical factors occurring in association with each bilirubin peak in the postoperative course found the jaundice related to transfusion and surgery in 11 instances, to sepsis and septicemia in 15 instances, and to hepatic dysfunction in 23 instances. Results indicated that admission estimates of SGOT and LDH levels, the height of the bilirubin peak and the postoperative day on which it occurs, and the white cell count and GGT at the time of the peak may be of use in the differential diagnosis. Four case reports were used to emphasize the fluctuating pattern of jaundice and the different etiologic factors that may predominate. Light and electron microscopy from three patients illustrated the structural alterations that accompany the biochemical impairment of liver function and enable a more precise appreciation of this syndrome. Hepatic dysfunction appears to be implicated in a high proportion of patients who develop post-traumatic jaundice, which frequently occurs as part of a spectrum of multiple organ failure.

Adolescent↗
PubMed1976

Alcohol and marijuana effects on ocular tracking.

Experienced alcohol and marijuana users were instructed to track with their eyes a small spot that moved horizontally back and forth in pendular (sinusoidal) motion across a 7.5-degree field. The frequency of spot oscillation was gradually increased from 0.5 to 3.0 Hz in 40 sec. Eye movement recordings showed the frequency at which smooth tracking and, soon thereafter, saccadic tracking broke down. These smooth and saccadic cutoff frequencies were reduced after administration of alcohol, but not after marijuana or placebo. For low alcohol doses, smooth tracking was impaired and saccadic tracking was unaffected, much like an effect previously reported for barbiturates. Alcohol seems to affect smooth tracking by increasing the central processing time required to generate the appropriate eye movement. It affects saccadic tracking by slightly decreasing saccadic velocity and to a greater extent by increasing latency time, part of which may be devoted to central processing. The site of action of alcohol appears to be central to both the paramedian pontine reticular formation and the flocculus of the cerebellum.

Adult↗
PubMed1976

A hypothesis for the increased oxygen affinity in haemoglobin Malmö.

Haemoglobin Malmöbeta97His leads to Gln, a high oxygen affinity haemoglobin which causes secondary erythrocytosis, is transmitted in an autosomal dominant manner. A hypothesis accounting for the high oxygen affinity, hyperbolic oxyhaemoglobin dissociation curve, and the relatively normal Bohr effect is presented. The purified abnormal haemoglobin from the present family provided biochemical and functional data for this hypothesis based on the allosteric model proposed by Perutz. Experimental results support the formation of a chemical bond between the -SH proton of the beta93 cysteine and the amide of oxygen of the substituted beta97 glutamine as an explanation for the high oxygen affinity of haemoglobin Malmö.

Hemoglobinopathies↗
PubMed1976

Red cell age-related changes of hemoglobins AIa+b and AIc in normal and diabetic subjects.

The minor hemoglobin components, hemoglobin AIa+b and hemoglobin AIc, were measured in the 10% youngest and 10% oldest erythrocytes of 15 normal and 14 diabetic subjects. Erythrocyte fractions were obtained by centrifugation in isopyknic concentrations of dextran: 28.5% of 40,000-mol wt dextran yeilded the 10% lightest of young cells, and 30.5% dextran provided the 10% heaviest or old erythrocytes. Both normal and diabetic erythrocytes contain increased amounts of Hb AIa+b and Hb AIc in old as compared to young cells. In normal subjects, young cells contained 1.2+/-0.2%, and old cells contained 1.8+/-0.4% Hb AIa+b. Corresponding values for diabetic cells were 1.7+/-0.6 and 2.6+/-0.9%. Hb AIc increased from 3.1+/-0.8 to 6.0+/-1.1% in normals and from 5.1+/-2.1 to 10.1+/-3.7% in diabetics. The results indicate that both cell age and diabetes are significant determinants of the amounts of Hb AIa+b and Hb AIc.

Adult↗
PubMed1976

Depression of growth hormone and cortisol response to insulin-induced hypoglycemia after prolonged oral delta-9-tetrahydrocannabinol administration in man.

Six hospitalized volunteer male subjects were given insulin, 0.15 U/kg, before and after 14 days of administration of delta-9-tetrahydrocannabinol (THC) at a dose of 210 mg/day. A diminished maximal serum human growth hormone (GH) increase followed the prolonged THC ingestion. The mean maximal GH response was: 52.6 ng/ml +/- 8.7 (+/-SE) before THC and 18.8 ng/ml +/- 6.7 (+/-SE) during THC, P less than 0.01; corresponding cortisol responses were 20.1 mug/dl +/- 3.0 before THC and 10.0 mug/dl +/- 1.1 during THC, P less than 0.05. The data suggest suppression of the hypothalamic-pituitary axis after prolonged high dose THC use. This is consistent with other reported endocrine effects of marijuana in man.

Administration, Oral↗
PubMed1976

A clinicopathologic study of hepatic dysfunction following shock.

Nineteen patients who had profound hypotensive shock were studied to correlate the light and electron microscopic appearances of the liver with the clinical and biochemical evidence of hepatic dysfunction. Despite the multiple etiologic factors that can result in jaundice in these patients, a fluctuating pattern occurs which enables the correlation of a bilirubin peak with the predominating etiologic factor. Immediately after shock, there was enzymatic and light and electron microscopic evidence of hepatocellular damage, resulting in a jaundice peak on the eighth to tenth day after the shock episode. This was followed by repair and regeneration of the liver as well as an increase in cholestatic enzyme levels. Later, bilirubin peaks occurred when hepatocellular function was further decreased or overloaded against this background of dysfunction related to the episode of shock. Recovery of hepatic function could continue or be delayed by intercurrent disease, particularly systemic infection. Support of hepatic function, similar to that available for pulmonary and renal failure may, in the future, be used to effect the prognosis of these patients.

Bilirubin↗