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Biomedical subjects

R A Robinson

Publications and source records attributed to R A Robinson.

At least 163 records · Page 9Linked to original sources
PubMed1985

5 Alpha-reductase activity in human prostate cancer is related to the histological differentiation of the tumour.

We have measured the activities of two androgen metabolizing enzymes in tissue obtained from thirty-nine patients with carcinoma of the prostate (CaP). The enzyme activities were correlated to the histological differentiation of the tumours based on the Gleason Score and also compared to the activities measured in fourteen age matched patients with nodular prostatic hyperplasia (BPH). Although the mean values for the 5 alpha-reductase in CaP (9.29 +/- 1.47 pmol/mg protein/30 min) were found to be significantly lower than the corresponding values in BPH (16.26 +/- 3.04 pmol/mg protein/30 min) (P less than 0.05), there were nonetheless significant differences within the cancer group and these were totally dependent on the degree of differentiation of the tumour. A progressively suppressed enzyme activity was measured as the carcinomatous tissue became more anaplastic. No correlation was, however, observed between tumour bulk which was also estimated histologically and 5 alpha-reductase, indicating that the activity of this enzyme is purely a function of the histological grade of the cancer and as such 5 alpha-reductase could be used as a biochemical marker for tumour differentiation. We also measured the 3 alpha (beta)-hydroxysteroid dehydrogenase activities in cancer of the prostate but our findings indicated no significant differences between the various stages of the cancer. Furthermore we were unable to correlate the activities of this enzyme with that of the 5 alpha-reductase. Nonetheless two interesting patterns relating to the 3 alpha (beta)-hydroxysteroid dehydrogenase emerged.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Hydroxysteroid Dehydrogenases↗
PubMed1984

Lingual abscesses in suckling and weaned lambs.

Lingual abscesses were found in lambs from 2 midwestern flocks. Lesions resulted in reluctance to feed, emaciation, and death. Plant material was demonstrated at the center of abscesses in 1 flock. Veterinarians should examine tongues carefully when investigating lamb mortalities.

Abscess↗
PubMed1984

Pneumonia and atrophic rhinitis in pigs from a test station--a follow-up study.

Pneumonia and atrophic rhinitis were studied for the second consecutive year in pigs at the same test station. Pneumonia was found to reduce mean daily gain by 3.3% for every 10% of the pig's lungs that had lesions. Atrophic rhinitis did not affect mean daily gain. There was no association between the development of atrophic rhinitis and the development of pneumonia. Pigs that were vaccinated with a Bordetella bronchiseptica bacterin did not have turbinate atrophy scores or mean daily gains different from those in pigs that were not vaccinated. Yorkshire and Hampshire pigs had higher prevalences and severity of pneumonia and atrophic rhinitis, compared with pigs of other breeds.

Animals↗
PubMed1984

Chondromyxoid fibroma in a carpal bone.

An unusual lesion developed in the trapezoid of a 25-year-old man. The tumor had histologic features most consistent with a diagnosis of chondromyxoid fibroma and had not recurred four years after curettage and bone grafting.

Adult↗
PubMed1984

Establishment and characterization of four new human non-small cell lung cancer cell lines.

Four new human non-small cell lung cancer cell lines have been established in vitro. These cell lines have been characterized by (a) growth of a tumor in nude mice with histopathology similar to that of the primary, (b) isoenzyme patterns phenotypically human and distinct from each other, (c) distinguishing karyotypic findings, (d) growth rate determinations, and (e) presence of epidermal growth factor receptors. Each of the cell lines will form colonies when directly seeded into a flask without soft agar. The development and availability of the four cell lines may facilitate in vitro studies of the biology of this common cancer. Their clonogenic potential may be of value in the study of sensitivity to antineoplastic agents. Their low passage level may mean that their antigens still resemble those of the primary tumor.

Adenocarcinoma↗
PubMed1983

A comparison of two methods for determining ultrasonic intensity for medical transducers.

The spatial and temporal average intensity (ISATA) is determined for four diagnostic ultrasound transducers by two methods: (a) direct measurements (beam profiling) with a miniature hydrophone, as described in the AIUM-NEMA standard, and (b) estimating from measurements of total power and assumptions about beam size. The latter method is frequently used by diagnostic ultrasound manufacturers when reporting output levels to users and regulatory agencies. However, due to the conventions for defining beam area, this method actually overestimates the spatial average intensity. For the four transducers tested, the estimated ISATA exceeds the measured ISATA by several hundred percent. The spatial peak, temporal average intensity (ISPTA) was also measured for the four transducers and is less than the estimated ISATA in every case.

Acoustics↗
PubMed1983

Effects of intrauterine challenge with Leptospira interrogans serovar hardjo on fertility in cattle.

The purpose of this study was to determine the effects of Leptospira interrogans serovar hardio on fertility in cattle. Twenty seronegative mature dairy cows were assigned to two groups. Group I (challenged cows) was bred by a seronegative bull followed by intrauterine infusion (within 30 minutes) of Leptospira interrogans serovar hardjo. Group II was bred by the same bull followed by intrauterine infusion of 5 ml of sterile culture medium. Blood samples were collected at two-day intervals to monitor serum antibody titers. Daily blood cultures for 10 days and weekly urine cultures for five weeks were performed to monitor the animals for leptospiremia and leptospiuria. Cows were slaughtered 35 days post-breeding, and their reproductive tracts were examined. All animals remained clinically normal following intrauterine challenge. There was no difference in pregnancy rates (Group I, 7/10; Group II, 6/10). All embryos, reproductive tracts, and kidneys appeared normal. A microscopic agglutination test (MA) showed that 4 of 10 challenged cows developed serum antibody titers between 8 and 20 days after challenge. However, on the basis of the hamster passive protection test, all challenged cows had serum antibodies present. All blood and urine cultures were negative through the experimental period, as were the final kidney and uterine cultures. In a second experiment, six seronegative cows were infused with killed microorganisms immediately after insemination. Results of a microscopic agglutination test and a hamster passive protection test indicated that these cows did not develop humoral antibodies against serovar hardjo. These results indicated that intrauterine inoculation of Leptospira interrogans serovar hardjo (hamster-adapted strain) following breeding did not affect pregnancy rates despite an intrauterine challenge which caused the development of humoral antibodies.

Journal Article↗
PubMed1982

Influence of cartilage particle size and proteoglycan aggregation on immobilization of proteoglycans.

Mechanisms by which proteoglycan aggregates are retained within cartilage were studied using two approaches: mechanical fragmentation of cartilage and reassociation of proteoglycans within extracted cartilage. The extractability of proteoglycans from fresh bovine nasal cartilage with low ionic strength buffer was found to vary from 13 to 45% depending upon the degree of cartilage fragmentation. Forty per cent of those extracted from finely fragmented cartilage (5-20-mu diameter) were found to be in aggregates which contained "link" proteins. A method was developed to reintroduce proteoglycans, which had been extracted with guanidine hydrochloride, into cartilage from which they had been extracted. Stability of the newly formed associations was assessed by re-extraction with a guanidine hydrochloride gradient. Purified proteoglycans alone or reduced and alkylated proteoglycans formed associations which were disrupted with less than 2 M guanidine hydrochloride. Addition of "link" proteins resulted in associations which required 2-4 M guanidine hydrochloride to be re-extracted. Association of proteoglycans into Sepharose 4B particles gave extraction patterns similar to reassociation into extracted cartilage. These findings are consistent with the hypothesis that proteoglycans are immobilized within cartilage through the formation of aggregates and suggest that retention is dependent upon the integrity of the collagen mesh.

Animals↗
PubMed1982

Border disease in a flock of Minnesota sheep.

A flock problem affecting newborn lambs on a Minnesota farm was investigated. The lambs had hairy fleece and rhythmic tremors, and were unthrifty. Histologic examination revealed hypomyelinization of the CNS and hypertrophy of primary follicles in the skin. A virus antigenically related to bovine viral diarrhea virus was isolated. Serum neutralization showed that a large number of flock ewes had much higher titers to bovine viral diarrhea virus than did control animals.

Animals↗
PubMed1982

Chronic production of defective-interfering particles by hamster embryo cultures of herpesvirus persistently infected and oncogenically transformed cells.

Highly passaged defective-interfering (DI) particle preparations of equine herpesvirus type 1 (EHV-1) were found to mediate the co-establishment of persistent infection and oncogenic transformation of permissive hamster embryo cells. Four cell lines, designated DI-1 to DI-4, were shown to possess biological properties typical of transformed cells and to induce the rapid formation of metastatic fibrosarcomas when injected into syngeneic LSH hamsters. Corresponding DI tumour cell lines, designated DI-1T to DI-4T, were found to be virus non-producing, to be transplantable in the hamster, and, like the four parent DI cell lines, to express EHV-1-coded antigens and to be resistant to superinfection with EHV-1 but not with a heterologous virus, vesicular stomatitis virus. All transformed cell lines, but not the tumour cell lines, contained a population of cells (2.6 to 9%) that continued to release infectious virus after 100 passages in culture. The production of interferon and selection of temperature-sensitive mutants did not appear to play a role in the maintenance of persistent infection. However, it was demonstrated that these persistently infected cells continued to release not only infectious virus but also DI particles after more than 2 years in culture. DI particles were shown to be present in released virus by: (i) detection of the defective virus DNA species (density 1.724 g/ml; standard EHV-1, density 1.716 g/ml) by CsCl analytical ultracentrifugation techniques; (ii) measurement of interference activity of virus released from DI-1 to DI-4 cells against standard EHV-1 replication; (iii) the presence of the 35 megadalton Bg/II fragment unique to the DI particle genome in DNA of released virus. These studies indicate that herpesvirus DI particles may function both in the initiation and maintenance of persistent infection and alter the cytocidal effects of infection to allow the establishment of oncogenic transformation and persistent infection.

Animals↗
PubMed1982

Growth factors, growth factor receptors, and cell cycle control mechanisms in chemically transformed cells.

Previous studies have shown that the chemically transformed AKR-MCA and C3H/MCA-58 cell lines spontaneously arrested growth at high saturation density in the G1 phase of the cell cycle because of depletion of low-molecular-weight nutrients (amino acids and glucose) from the medium. The nontransformed parent cell lines, AKR-2B and C3H/10T1/2, spontaneously arrest growth in G1 at low saturation density because of depletion of essential serum growth factors. If prevented from becoming deficient in growth factor by maintenance in medium with mitogens such as epidermal growth factor (EGF), fibroblast growth factor, or the tumor promoter 12-O-tetradecanoylphorbol-13-acetate, the nontransformed AKR-2B cells behave similarly to the transformed cells and arrest growth in G1 at high saturation density because of nutrient deficiency. This suggests that a major difference between the nontransformed and chemically transformed cells is an inability of the latter to achieve growth factor deficiency. In addition, the transformed AKR-MCA and C3H/MCA-58 cells show greatly diminished detectable EGF receptors. These observations could be accounted for by the endogenous production of the response to a growth factor-like substance by the transformed cells. Preliminary data indicate that these chemically transformed cells release a transforming growth factor (TGF) into serum-free medium. Whether TGF is similar or identical to the previously described sarcoma growth factor remains to be established.

Cell Cycle↗
PubMed1982

Cell cycle variation in 125I-labeled epidermal growth factor binding in chemically transformed cells.

Previous studies have shown that the nontransformed AKR-2B cells when arrested in the G1 phase of the cell cycle due to low-molecule-weight nutrient (amino acid) deficiency exhibit a 5- to 10-fold lower level of epidermal growth factor (EGF) receptor activity than do the same cells in the rapidly growing state or arrested in G1 due to growth factor deficiency. The chemically transformed AKR-MCA and C3H/MCA-58 cell lines spontaneously arrest growth in G1 due to nutrient deficiency when grown to saturation density in medium with 10% fetal bovine serum. An examination of 125I-labeled EGF binding in rapidly growing and G1-arrested AKR-MCA and C3H/MCA-58 cells showed that the G1-arrested chemically transformed cells also have a 10- to 20-fold reduction in the amount of 125I-labeled EGF binding relative to the same cells in the rapidly growing state. Stimulation of DNA synthesis in the arrested cells by the addition of serum-free medium caused a 6- to 10-fold increase in 125I-labeled EGF binding. This recovery of receptor activity was inhibited by actinomycin D and cycloheximide, suggesting that new messenger RNA synthesis as well as increased protein synthesis is necessary for the recovery of EGF binding. A comparison of EGF binding in C3H/MCA-58 cells and the nontransformed parent line (C3H/10T 1/2) in the rapidly growing state showed the same approximate level of receptor activity. However, the rapidly growing AKR-MCA cells had approximately one-tenth the amount of EGF binding as did the rapidly growing nontransformed parent line (AKR-2B). Scatchard analysis of binding data showed a 10-fold greater number of receptors in the AKR-2B cells relative to the AKR-MCA cells with a lesser difference in apparent receptor affinity. The chemically transformed BP-3T3, like the other two chemically transformed lines, was also demonstrated to arrest growth spontaneously due to nutrient deficiency with an associated 100-fold decrease in EGF binding. Rapidly growing BP-3T3 cells had only slightly less 125I-labeled EGF binding than did the nontransformed parent line (BALB-3T3) in the rapidly growing state. The data indicate that one mechanism for reduction of EGF binding in chemically transformed cells is the propensity of these cells to arrest growth in G1 at saturation density due to low-molecular-weight nutrient deficiency, a state associated with decreased EGF binding.

Amino Acids↗