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Biomedical subjects

R A Berg

Publications and source records attributed to R A Berg.

At least 145 records · Page 8Linked to original sources
PubMed1983

Language-related skills in children with acute lymphocytic leukemia.

The success of cranial irradiation and chemotherapy in the treatment of acute lymphocytic leukemia (ALL) has raised concerns about possible central nervous system damage in long-term survivors. The current study focused on language-related skill measures obtained as part of a neuropsychological test battery. Performance was analyzed as a function of age at diagnosis and age at evaluation in a sample of 110 children with ALL (mean age = 13.28 years). Results, although for the most part nonsignificant, do reveal significantly poorer performance on an Aphasia Screening Test rating by those diagnosed early (at or before five years of age) and assessed at or before 13 years of age when contrasted with those diagnosed early and assessed after their thirteenth year. Further analysis revealed a significant decline in spelling scores for those off therapy for more than two years. There was also a consistent trend for decline across most language-related skills measures as time off therapy increased. These results reflect either recovery from mild acute language dysfunction over time superimposed on a general trend for decline in language-related skills as time off therapy increases, or sampling error. Suggestions for future lines of investigation are discussed.

Achievement↗
PubMed1983

Cutaneous amebiasis.

An infant with cutaneous amebiasis of the vulva and amebic liver abscess is described. Epidemiologic investigations and serologic studies were crucial in establishing the diagnosis. The vulvar amebic ulcers responded dramatically to metronidazole therapy. Cutaneous amebiasis is a rare complication of Entamoeba histolytica infection which should be considered in the differential diagnosis of perineovulvar or penile ulcers. Cutaneous amebiasis may also occur on the abdominal wall surrounding a draining hepatic abscess, colostomy site, or laparotomy incision.

Amebiasis↗
PubMed1982

Modulation of collagen production by fibroblasts. Effects of chronic exposure to agonists that increase intracellular cyclic AMP.

Cultured human lung fibroblasts were evaluated for their responsiveness to isoprenaline (isoproterenol) or prostaglandin E2 before and after chronic incubation with the agonist. Cells incubated for 6 h with either agonist were suppressed in terms of collagen production and exhibited increased intracellular cyclic AMP. Cells incubated for 72 h with the agonist and then re-challenged for 6 h with the same agonist did not demonstrate suppressed collagen production or increased cyclic AMP. Cells incubated for 72 h with isoprenaline still responded to prostaglandin E2 when challenged for 6 h; however, when the order of agonist exposure was reversed, cells incubated with prostaglandin E2 did not respond to a challenge by isoprenaline. If cells were allowed to recover for 48 h without the agonist after a 72 h chronic incubation, they recovered their responsiveness to the agonist. The results indicate that, although cultured fibroblasts may become desensitized to one agonist, they may retain their sensitivity to a second agonist and chronic suppression of collagen production may be achieved by alternate exposure to isoprenaline and prostaglandin E2.

Cell Line↗
PubMed1982

beta-Aminopropionitrile prevents bleomycin-induced pulmonary fibrosis in the hamster.

beta-Aminopropionitrile (beta APN), an agent that prevents collagen accumulation in tissues, was evaluated for its ability to prevent excess collagen formation in bleomycin-induced pulmonary fibrosis in the hamster. Two groups of animals received a single endotracheal dose of bleomycin; one of these was injected with beta APN twice daily for 30 days. A third group received endotracheal saline and a fourth group received saline and beta APN. After 30 days, we measured pressure-volume curves of saline-filled lungs, collagen content, and degree of fibrosis. Endotracheal bleomycin increased collagen content, decreased lung volume, and produced fibrosis and a mortality rate of 51%. The administration of beta APN to bleomycin-treated animals prevented excess collagen accumulation and diminished total protein, reversed volume diminution, produced less fibrosis, and improved the mortality rate to 24%; beta APN alone had no effect on lung mechanics or collagen content. The biochemical, functional, and structural features of bleomycin-induced lung fibrosis are amenable to control with beta APN.

Aminopropionitrile↗
PubMed1982

The effect of cis-4-hydroxy-L-proline on intracellular degradation of newly synthesized collagen by freshly isolated chick tendon fibroblasts.

Freshly isolated embryonic chick tendon cells were incubated for 6 hrs in suspension culture in the presence of the proline analogue, cis-4-hydroxyproline to cause the cells to synthesize collagen which was incapable of becoming triple helical. The cells were evaluated for the percentage of total protein synthesis devoted to collagen and for the percentage of newly synthesized collagen which was rapidly degraded. Collagen production in the presence of cis-4-hydroxyproline was reduced from 25% to 7% of total protein synthesis. Under normal conditions the cells degraded 8% of their newly synthesized collagen but when the cells were incubated in the presence of cis-4-hydroxyproline, 25% of their total collagen synthesized was degraded to dialyzable peptides. The enhanced degradation of nonhelical, analogue containing collagen was inhibited by inhibitors of lysosome function. These observations provide support for the concept that fibroblasts are able to recognize and degrade a portion of their newly synthesized collagen, and that defective collagen may be selectively degraded by an intracellular lysosomal process. Enhanced intracellular degradation can in part explain the decrease in collagen production by freshly isolated tendon fibroblasts incubated with cis-4-hydroxyproline.

Ammonium Chloride↗
PubMed1981

Impaired immune response of splenectomised patients to polyvalent pneumococcal vaccine.

Immune response to polyvalent pneumococcal vaccine was measured in normal volunteers and splenectomised patients, by means of a newly developed enzyme-linked immunosorbent assay for pneumococcal antibodies. IgG and IgM responses to eight of the nine polysaccharides tested were markedly impaired in splenectomised patients. The response of splenectomised patients was less than that of the controls in terms of absolute titre of antibody achieved, relative rise in titre (fold increase of post-immunisation titre over pre-immunisation titre), and rate of rise.

Antibodies, Bacterial↗
PubMed1981

Procollagen production and procollagen messenger RNA levels and activity in human lung fibroblasts during periods of rapid and stationary growth.

The production of procollagen molecules by human diploid fetal lung fibroblasts (HFL-1 cells) remains constant in both rapid and stationary growth phases. However, log phase cells degrade 3-fold more newly synthesized collagen inside the cell prior to secretion than do stationary phase cells. Procollagen mRNA levels, measured by hybridization with a type I procollagen mRNA-specific complementary DNA, are approximately 2-fold higher in confluent cells than in log phase cells. There are no significant differences in the ability of either log phase or confluent HFL-1 cell procollagen mRNA to be translated in an in vitro cell-free translation system. Therefore, the ability of HFL-1 cells to maintain constant collagen production irrespective of the growth status of the cells results from the combined action of a number of regulatory mechanisms, including changes in procollagen mRNA levels, the utilization of procollagen mRNA, and intracellular procollagen degradation.

Cell Division↗
PubMed1981

Structural brain deficits in schizophrenia. Identification by computed tomographic scan density measurements.

Research has suggested the presence of brain damage as a cause or concomitant of chronic schizophrenia. The most recent research in this area has been the identification of abnormalities in schizophrenia by computed tomographic (CT) scans. A study was done to investigate localized changes in CT scan density numbers in the brains of schizophrenic patients, as opposed to the brains in normal control subjects. Twenty-four normal subjects and 23 schizophrenic patients were tested with CT scans. Density measurements in each area of the brain (left, right, anterior and posterior) were compared to three separate CT scan levels. Of six measurements of anterior left-hemisphere density, it was found that five showed lower density in schizophrenic brains, as compared with normal brains. Of the remaining 18 measurements that evaluated other areas of the brain, only three differentiated between schizophrenic patients and normal subjects. The results support the hypothesis that there are primary structural deficits in some schizophrenic patients, and these deficits are centered in and around the anterior area of the left (dominant) hemisphere. The results also demonstrated further implications.

Absorptiometry, Photon↗
PubMed1981

An improved method for the purification of vertebrate prolyl hydroxylase by affinity chromatography.

Prolyl hydroxylase was purified from extracts of 13-day old chick embryos by an improved affinity column technique. Prolyl hydroxylase was released from the affinity column by poly-L-proline and was separated from the other proteins and from the poly-L-proline by ion exchange chromatography. This improvement allowed eluates from up to six affinity columns to be pooled and chromatographed in a single step. Furthermore, a major contaminating protein which was difficult to remove from the eluted enzyme using the previous procedure was easily separated by the ion exchange column. The overall advantage of the new technique allows much larger amounts of prolyl hydroxylase to be prepared at a single time than was previously possible.

Animals↗
PubMed1981

Prevention of bleomycin-induced pulmonary fibrosis in the hamster by cis-4-hydroxy-l-proline.

We investigated the effect of the proline analogue cis-hydroxyproline on pulmonary fibrosis produced by intratracheal administration of bleomycin in hamsters. Two groups of animals received a single dose of bleomycin; one of these groups was also injected with cis-hydroxyproline twice daily for 30 days. Control animals received intratracheal saline. Lungs were examined on day 30. In the bleomycin group, the collagen content of lungs was 131% of the control value (p less than 0.05). Administration of cis-hydroxyproline decreased collagen accumulation to 114% of the control value (p less than 0.05). Pressure-volume curves were significantly shifted downward and to the right of control in the bleomycin group; this shift was partially prevented by cis-hydroxyproline. Morphometric studies showed that alveolar walls comprised 15% of the lung parenchyma in the control group and 19% in the bleomycin group (p less than 0.05). Administration of cis-hydroxyproline significantly decreased alveolar walls to 16% of the lung parenchyma (p less than 0.05). We conclude that cis-hydroxyproline partially prevents the chemical, structural, and functional changes of bleomycin-induced pulmonary fibrosis in the hamster.

Animals↗