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Biomedical subjects

R Parker

Publications and source records attributed to R Parker.

At least 235 records · Page 13Linked to original sources
PubMed1978

Storage of heart valve allografts in glycerol with subsequent antibiotic sterilisation.

Fresh allograft valves stored in a nutrient medium at +4 degrees C have a limited storage time of eight weeks. Dura mater has been stored in glycerol for longer periods, and this paper presents work on the glycerol storage of allograft heart valves. The elastic properties of the valve cusps showed a fall during storage in glycerol that was associated with an altered histological appearance of the cusp tissue. The loss in nuclearity in the histological sections of stored tissue was partially responsible for the observed decrease in viability during storage. All these changes during storage in glycerol, or glycerol and subsequent antibiotic treatment, were similar to the changes seen in valves stored in a nutrient medium. Glycerol therefore offers an alternative storage system to the cold nutrient medium but has no practical advantages. Glycerol alone will not sterilise the allograft tissue, and a post-storage treatment with antibiotics is essential.

Anti-Bacterial Agents↗
PubMed1978

DES action.

Explore the source record for details and available documents.

Diethylstilbestrol↗
PubMed1978

Liquid nitrogen storage of Anaplasma marginale complement-fixation antigen by a multiple small aliquot technique.

Anaplasma marginale complement fixation test antigens were frozen as drops in liquid nitrogen using an easily constructed apparatus. Economy in the use of antigen was achieved as the frozen drops were retrieved from storage in any required volume. The potency of the antigen was unaffected by the freezing and thawing technique. The technique is useful for storing other biological reagents.

Anaplasma↗
PubMed1977

Are pelvic irradiation and routine staging laparotomy necessary in clinically staged IA and IIA Hodgkin's disease?

Thirty-nine patients with clinically staged IA and IIA Hodgkin's disease were treated with mantle plus paraaortic/splenic irradiation between 1968 and 1975. All patients had supradiaphragmatic presentations, and none had staging laparotomies. With a follow-up time of 1 to 9 years, mean 4.3 years, the overall relapse-free survival is 92% (100% for stage IA and 89% for stage IIA). The absolute relapse-free 5-year survival is 91% There were no pelvic recurrences. These data show that routine staging laparotomy and pelvic irradiation are not indicated for clinically staged IA and IIA Hodgkin's disease with supradiaphragmatic presentation. The criteria for staging laparotomy in early-stage Hodgkin's disease are discussed.

Adolescent↗
PubMed1977

Elasticity of frozen aortic valve homografts.

Homograft aortic valves were treated and stored in different ways and then tested for elastic qualities. It appears from the findings that the most satisfactory long-term storage technique is to flash-freeze the valves in the presence of dimethyl sulphoxide immediately after dissection.

Aortic Valve↗
PubMed1977

Changes in tonsillectomy rates associated with feedback and review.

Among 13 Vermont Hospital Service Areas, tonsillectomy rates decreased over a five-year period. In 1969, the rates in seven areas exceeded the estimated United States national rate; by 1973, the average rate for all areas had declined 46% and only one area remained above the U.S. rate. Much of the change occurred after feedback of data to the Vermont State Medical Society demonstrating 1969 variations. In 12 of the 13 areas, the relationship between feedback and change in clinical practices could not be documented; however, physicians in the area with the highest rate reviewed the indications for tonsillectomy and adopted a second opinion procedure for reviewing candidates for the surgery. The experience suggests that feedback of population-based data on incidence of procedures may be a valuable tool for the peer review process.

Adenoidectomy↗
PubMed1976

Visual pathways, acuity dominance, and visual half-field asymmetry.

The effects of the visual pathways and acuity dominance on visual half-field (VHF) recall of verbal stimuli were investigated with 36 right-handed male undergraduates, with the use of the Hines-Satz short-term memory paradigm under monocular conditions. Scores for stimuli transmitted via the left temporal and right nasal pathways were significantly greater than those for stimuli transmitted via the left nasal and right temporal pathways. No other significant differences were found for either the pathways or acuity dominance variables. The results were hypothesized to reflect the primary influence of hemispheric asymmetry of function on the VHF recall task.

Adolescent↗
PubMed1976

Immunotherapy with nonviable microbial components.

Structural components of microorganisms have been studied for immunopotentiating effect with the aid of transplantable (line 10) tumors in syngeneic guinea pigs. Microbial components were associated with oil droplets, suspended in Tween-saline, and injected intralesionally. BCG cell walls, given in this way, produced regression and cure of 50-60% of established tumors, as did viable BCG. Lipid extraction markedly reduced the tumor-regressing potency of cell walls, but P3, a trehalose mycolate present in the extract, restored full activity to the cell wall residue. P3 alone was nonsensitizing and had no antitumor activity, but it enhanced the latter property of various other microbial products. For example, the cure rates produced by cell walls of M. tuberculosis, M. bovis, M. phlei, or M. smegmatis were enhanced from 20-60% to as much as 90% by addition of P3. P3 also conferred antitumor activity on products from unrelated microbes, such as cell walls of E. coli, and in combination with endotoxins from rough Re mutant salmonellae, it produced cure rates of up to 93%. These results suggest that P3 is essential to the immunopotentiating activity of mycobacteria and that it may be broadly applicable in immunotherapy of cancer with microbial agents.

Animals↗