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Biomedical subjects

C Anderson

Publications and source records attributed to C Anderson.

At least 613 records · Page 34Linked to original sources
PubMed1977

Degradation of parathyroid hormone and fragment production by the isolated perfused dog kidney. The effect of glomerular filtration rate and perfusate CA++ concentrations.

The renal degradation of intact bovine parathyroid hormone (b-PTH 1-84) was studied with the isolated perfused dog kidney. Disappearance of b-PTH 1-84 from the perfusate occurred concomitantly with the appearance of smaller molecular weight forms of immunoreactive parathyroid hormone (PTH). These smaller molecular weight PTH fragments included both carboxyl and amino terminal regions of the PTH peptide. Perfusate from kidneys with lower glomerular filtration rates (GFR) contained b-PTH 1-84 for longer periods of time than kidneys with higher GFRs, and perfusate from kidneys with lower GFRs demonstrated greater accumulation of carboxyl terminal PTH fragments. Perfusate containing high Ca++ concentrations retarded, and perfusate with low Ca++ concentrations accelerated the rate of degradation of b-PTH 1-84 by the kidney. These studies, therefore document the production of PTH fragments during the course of intact hormone degradation by the kidney. They also demonstrate renal clearance of the PTH fragments produced and define the effects of glomerular filtration rate and calcium concentrations on degradation of intact hormone and the clearance of PTH fragments.

Animals↗
PubMed1977

The renal handling of parathyroid hormone. Role of peritubular uptake and glomerular filtration.

The mechanisms of uptake of parathyroid hormone (PTH) by the kidney was studied in anesthetized dogs before and after ureteral ligation. During constant infusion of bovine PTH (b-PTH 1-84), the renal arteriovenous (A-V) difference for immunoreactive PTH (i-PTH) was 22+/-2%. After ureteral ligation and no change in renal plasma flow, A-V i-PTH fell to 15+/-1% (P < 0.01), indicating continued and significant uptake of i-PTH at peritubular sites and a lesser role of glomerular filtration (GF) in the renal uptake of i-PTH. Since, under normal conditions, minimal i-PTH appears in the final urine, the contribution of GF and subsequent tubular reabsorption was further examined in isolated perfused dog kidneys before and after inhibition of tubular reabsorption by potassium cyanide. Urinary i-PTH per 100 ml GF rose from 8+/-4 ng/min (control) to 170+/-45 ng/min after potassium cyanide. Thus, i-PTH is normally filtered and reabsorbed by the tubular cells. The physiological role of these two mechanisms of renal PTH uptake was examined by giving single injections of b-PTH 1-84 or synthetic b-PTH 1-34 in the presence of established ureteral ligation. After injection of b-PTH 1-84, renal A-V i-PTH was 20% only while biologically active intact PTH was present (15-20 min). No peritubular uptake of carboxyl terminal PTH fragments was demonstrable. In contrast, after injection of synthetic b-PTH 1-34, renal extraction of N-terminal i-PTH after ureteral ligation (which was 13.4+/-0.6% vs. 19.6+/-0.9% in controls) continued for as long as i-PTH persisted in the circulation. These studies indicate that both GF and peritubular uptake are important mechanisms for renal PTH uptake. Renal uptake of carboxyl terminal fragments of PTH is dependent exclusively upon GF and tubular reabsorption, whereas peritubular uptake can only be demonstrated for biologically active b-PTH 1-84 and synthetic b-PTH 1-34.

Animals↗
PubMed1977

Scanning electron microscopic observations on bone.

The maceration technique employed in the preparation of specimens of bone for museum purposes has also been found to be of use in the preparation of fresh specimens for study with the scanning electron microscope. The technique requires less technical supervision, permits a greater underprocessing to overprocessing margin, and allows comparability of recent biopsy material with previously macerated bone specimens with no less detail than that found by other authors using other techniques on biopsy material.

Bone and Bones↗
PubMed1977

The effect of chronic low level lead intoxication on the Haversian remodeling system in dogs.

The greatest portion of lead ingested by human beings or experimental animals is stored in bone. Once in bone, lead is difficult to remove. It may have a half-life of 20 years or more and could interfere with bone metabolism. The effects of lead intoxication on the production of intercellular matrix have been reported previously but the effects of lead on bone turnovers rates were not reported. In this paper we reported the results of a study of the effects of lead on bone turnover in dogs. Differences between experimental and control dogs were found when measuring appositional rates, radial closure rates, activation frequencies, osteon formation times, and bone formation rates. We found that dogs subjected to a low dose (1.3 mg. per kg. per day) of lead over a long period of time (201 days) showed a statistically significant decrease in bone formation activity at the cell (90 per cent), tissue (85 per cent), and organ (78 per cent) levels when compared to controls. Although these observations were made on a small experimental and control sample (four dogs), they suggest that chronic low dose lead intoxication does alter normal bone physiology.

Animals↗
PubMed1976

Characterization of an adenovirus early protein required for viral DNA replication: a single strand specific DNA binding proteins.

1. The human adenoviruses types 2, 5 and 12 code for the production of a single strand specific DNA binding protein. The molecular weights of these proteins were 72,000 for types 2 and 5 and 60,000 for type 12. In all three cases proteolytic breakdown fragments of these binding proteins (48,000 MW) were also observed. 2. Analysis of the methionine containing tryptic peptides of these proteins indicate that the types 2 and 5 proteins are similar and clearly distinguishable from the type 12 protein. The peptide maps of these three viral proteins are clearly different from a similar protein found in mock infected cells. 3. Temperature sensitive mutants of type 5 (H5ts125) and type 12(H12tsA275) adenoviruses fail to produce these proteins at the nonpermissive temperature. H5ts125 infected cells grown at the permissive temperature produce a 72,000 MW protein that is thermolabile, for continued binding to DNA, when compared to type 5 wild type adenovirus 72,000 MW protein. An analysis of the phenotype of this adenovirus mutant indicates that it codes for a viral function at early times after infection that is required for viral DNA replication. 4. The in vitro translation of adenovirus specific m-RNA results in the synthesis of a small amount of a 72,000 MW protein that binds to single stranded DNA just like the authentic adenovirus DNA binding proteins produced in infected cells. 5. Adenovirus anti-Tumor antigen (T) anti-serum from hamsters carrying independently derived adenovirus tumors, have been tested for the presence of antibody to purified DNA binding proteins. One antiserum is positive for these antibodies while the other is negative. These results indicate that some, but not all, adenovirus tumors contain large enough levels of the DNA binding proteins to elicit an antibody response. 6. The type 5 adenovirus temperature sensitive mutant, H5ts125, that codes for a thermolabile DNA binding protein, was complemented or suppressed at the nonpermissive temperature, for the replication of adenovirus DNA, by SV40. SV40tsA temperature sensitive mutants, defective in SV40 DNA replication, do not suppress or complement H5ts125 at the nonpermissive temperature.

Adenoviridae↗
PubMed1976

Uptake and loss of inorganic mercury in the eastern oyster (Crassostrea virginica).

Eastern oysters (Crassostrea virginica) were found to accumulate significant levels of mercury on exposure to relatively low concentrations of mercuric chloride. Accumulation occurred in two distinct phases which may be described as a two compartment system in which accumulation is logarithmic in the first phase and linear in the second. Mercury, during the initial phase, showed a minimum outward concentration flux of 0.025 hr-1 indicating reversibility of accumulation prior to the change in phase. However, mercury was not excreted at the end of the second phase following exposure to 10, 40, 80, and 100 mug/1 for 256 hr.

Animals↗
PubMed1976

Leukocyte migration inhibition by soluble extracts of MCF-7 tissue culture cell line derived from breast carcinoma.

Studies were conducted to determine whether MCF-7, a tissue culture cell line derived from a pleural effusion of a patient with breast carcinoma, could be used as a source of tumor-associated antigen for direct leukocyte migration-inhibition (LMI) assays. Of 32 patients with breast carcinoma, 27 (84.4%) gave positive migration-inhibition results on their initial tests with a 25-mug protein/ml concentration of a 3 M KCl extract of MCF-7; 1 of 24 (4.5%) normal donors reacted with MCF-7. An intermediate incidence of reactivity (7/16) was observed with the extract when leukocytes of patients with melanoma, lung carcinoma, and Ewing's sarcoma were used. In further specificity studies, leukocytes of patients with breast carcinoma gave a lower incidence of LMl reactivity than did those of patients with Ewing's sarcoma and lung carcinoma with KCl extracts of the appropriate histologic type of tumor. The results indicated that the MCF-7 cells possessed a tumor-associated antigen to which many patients with breast carcinoma are sensitized.

Antigens, Neoplasm↗
PubMed1976

Profiles of couples seeking sex therapy and marital therapy.

Assessment of 29 couples seeking marital therapy and 25 seeking sexual therapy at the same institution permitted the delineation of two distinct profiles. Although the two groups were similar in the degree of their sexual and marital difficulties and in demographic characteristics, the relationships of the sex therapy couples were generally characterized by satisfaction and affection, whereas those of the marital therapy couples were often antagonistic. In addition, the sex therapy couples tended to be less conservative and more thoughtful in their approach to life and their problems.

Demography↗
PubMed1976

Ion chromatography: a new technique for clinical chemistry.

Ion chromatography is a new analytical technique in which the ions to be analyzed are separated on a special pellicular ion-exchange column. Once separated, the effluent from the separating column passes into a second ion-exchange column, which removes the eluent or buffer ions from the moving phase without removing the sample ions, which are detected and measured by electrical conductivity on a background of low conductance. Trace quantities can be so determined. This technique has been applied to four biological fluids: blood serum, tissue extract, urine, and cerebrospinal fluid. It is shown to be a practical analytical tool, particularly for ions having no chromophores, such as sodium, ammonium, potassium, magensium, calcium, chloride, nitrite, phosphate, and sulfate.

Calcium↗
PubMed1975

Sexual attitude reassessment workshops: effect on spinal cord injured adults, their partners and rehabilitation professionals.

Five workshops, focused on the sexuality of adults with acquired spinal cord injuries, were offered for rehabilitation professionals and spinal cord injures adults between December 1971 and October 1972 by the University of Minnesota's Program in Human Sexuality and Department of Physical Medicine and Rehabilitation. The fifth workshop was jointly sponsored with the American Academy of Physical Medicine and Rehabilitation (AAPM&R) and included an optional third day on sexual counseling. The objectives of the workshops were to assist the professional to be more helpful with others and the disabled to be more helpful to themselves. These objectives were accomplished by demythologizing sexual behavior, desensationalizing sexual stimuli and aiding the disabled person and professional to come to an understanding and acceptance of the sexuality of themselves as well as others. Preworkshop, immediately postworkshop and follow-up questionnaires evaluated the effects of the seminars upon all participants: disabled, able-bodied, professional and nonprofessional. Of the 76 who returned anonymous questionnaires mailed to the 95 spinal cord injured adults and their partners, 96.0 per cent reported that they were gland they attended, 82.8 per cent stated that they were personally benefited and 90.8 per cent reported that they would recommend the program to others like themselves. Of the 168 signed evaluations, 119 were returned by the professional group. Of 112 indicating that they or their institutions were currently involved in providing sexual counseling and education to the physically disabled, 97.3 per cent reported that the University of Minnesota workshop had given ideas, impetus or form to the current effort. Sexual attitudes and attitude changes in the AAPM&R-sponsered workshop were similar to those measured in participants in other workshops involving medical and seminary students and community members. Further workshops have been planned based upon these results.

Attitude to Health↗