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Biomedical subjects

R Wallace

Publications and source records attributed to R Wallace.

At least 163 records · Page 9Linked to original sources
PubMed1976

The goat mammary gland as a model infection site for Neisseria gonorrhoeae.

Live and formalin-killed gonococci were instilled into the mammary glands of lactating and nonlactating goats. In lactating goats viable gonococci elicited a limited inflammatory process whereas in non-lactating goats, severe inflammation and swelling appeared and peaked on the 3rd day after instillation and persisted for about 10 days. No viable gonococci were recovered after the first day, but fluorescent antibody staining showed gonococci in the exudate from non-lactating goats up to 7 days after instillation.

Animals↗
PubMed1976

Antibody production in milk serum of goats experimentally infected with Neisseria gonorrhoeae.

Instillation of the goat's mammary gland with Neisseria gonorrhoeae colony type T1 has elicited and antibody response in the goat milk serum (GMS). Purification, and characterization of the GMS by gel filtration, electrophoresis, immunodiffusion, analytical ultracentrifugation, and serological analyses demonstrated thtat the active immune component was mainly in the IgA and IgG fractions (F2 and F3) of GMS.

Animals↗
PubMed1976

Studies with 2,5-piperazinedione, 3,6-bis(5-chloro-2-piperidyl)-,dihydrochloride. I. Cell kinetic and biologic effects in cultured L1210, human epidermoid No. 2, and adenocarcinoma 755 cells.

Experimental results obtained with cultured L1210, human epidermoid No. 2, and Adenocarcinoma 755 cells are consistent in showing that inhibition of proliferation of the cells by 2,5-piperazinedione, 3,6-bis(5-chloro-2-piperidyl)-,dihydrochloride is accompanied by cell enlargement. Although cells initially in the G2 phase when exposure to the agent is begun can probably proceed through mitosis and divide, cells that are initially in G1 and S phases accumulate in the G2 phase. Progression of cells to G2 phase during the period of exposure to the agent is not a requisite for cell-killing, because cells exposed for periods insufficient to permit their accumulation in G2 are killed.

Adenocarcinoma↗
PubMed1976

Influence of size, protein concentration, protein synthesis inhibitors,and carbon on clearance of enzymes and proteins from blood.

In order to (1) clarify the mechanism(s) for clearance and maintenance of protein levels from and in extracellular fluids, and (2) explore the possibility of interconnections between enzyme plasma levels and those of tissues, rats were injected with glutamate dehydrogenase, phosphoglycerate, encolase, carbamyl phosphate synthetase, serine dehydratase, deoxyribonuclease I, ribonuclease A, hemoglobin, and human serum albumin. A close relationship between the molecular weights of enzymes and the rates of clearance was found.

Animals↗
PubMed1976

Effects of Medicare on hospital use: a disease-specific study.

This paper presents results of a study to determine 1) the effects of Medicare on the patients of hospital use in specific disease groups, and 2) the sensitivity of length of stay and proportions of admission in specific disease groups to "short-run" changes in hospital occupancy rates. The analysis indicates that Medicare did increase utilization of hospital services by patients 65 and over through increases in both admissions and average length of stay. The largest increases occurred in the lower risk disease categories, although it is pointed out that this result does not necessarily imply a misallocation of hospital resources. The results also indicate significant differences among different socioeconomic groups and a much greater initial impact on the 75 and over age group than on the 65-74 age group.

Age Factors↗
PubMed1975

A mouse intracerebral infection with Neisseria gonorrhoeae.

An intracerebral challenge of HPB black mice with Neisseria gonorrhoeae is described. In this mode, the mice died from 1 to 6 days after challenge, and T1 organisms were obtained up to the fifth day from brain, liver, kidney, and spleen. Experimental gonococcal vaccines gave good protection against the challenge.

Animals↗
PubMed1975

Gonococcal growth factors in tissue cultures.

Growth of Neisseria gonorrhoeae in the presence of Rhesus monkey kidney (RE2) cells containing Eagle's minimal essential medium (MEM) 'conditioned' by 18-20 h of contact with RE2 cells began 3-4 h after inoculation and by 16-20 h had reached a maximum. When 'conditioned' medium (CM) was removed from the tissue cells and replaced with fresh medium a 5-6 h lag period occurred before multiplication of gonococci began and by 16 h growth was also near a maximum. CM removed from tissue cells supported the growth of six strains of N. gonorrhoeae. Three strains failed to grow in CM but multiplied when tissue cells were present. None of the strains grew in the presence of tissue cells killed by heating or in tissue-culture medium alone. Of the six strains of N. gonorrhoeae which grew in CM, three kept as their major (90%) population T1 colonies, while the remaining strains produced T1 organisms and T1A, T3, and T4 colonial variants. These results indicate that tissue cells secrete growth factors which support the growth and maintenance of T1 colonial forms of certain strains of N. gonnorhoeae.

Animals↗
PubMed1975

Correlation between in vivo and in vitro metabolic measurements. Maximum capacity for urea synthesis.

Estimations of enzyme activity in vivo have been or can often only be done at unphysiological conditions. A main biochemical goal is to correlate in vivo and in vitro measurements. A possible approach to this problem is presented based on forcing metabolic activity in vivo to the maximum for a certain metabolic sequence. Since the urea synthesis system, including maximal rates of enzyme activities, is well known, we have compared in vitro maximum rates for the individual enzymes of urea synthesis with in vivo rates as judged by urea levels in blood of rats given large amounts of protein. The excellent agreement found between the calculated maximum activities from in vitro measurements to the time needed to metabolize a protein overload is presented and comments made on its significance and on the importance of maintaining protein intake at moderate levels, for the capacity of the urea system is limited. Since the intake of large quantities of protein increases the urea level in blood and in other tissues and since high urea levels are somewhat deleterious "per se" and particularly due to equilibrium with cyanate, ingestion of excessive amounts of protein is at best expensive and possibly hazardous.

Animals↗
PubMed1975

The chick embryo in studies of virulence and immunity with Neisseria Gonorrhoeae.

Intravenous inoculation of 11-day old chick embryos with Neisseria gonorrhoeae has confirmed the original observation of Bumgarner and Finkelstein that T1 and T2 gonocci are significantly more virulent than T3 and T4. Pili do not seem to be solely responsible for this virulence, since elimination of pili did not effect either the viability or the virulence of N. gonorrhoeae. In neutralization studies, there was only one log difference between the ability of normal and hyperimmune rabbit serum to protect the embryo against gonoccocal infection. However, when mouse sera were used in the same chick embryo system a clear difference was noted between the protective activity of normal serum and that antisera elicited in mice by purified gonococcal antigens. It is suggested therefore that mouse antisera be used in this chick embryo model for the assay for gonococcal antigens.

Animals↗
PubMed1974

Role of typhoid antigens in protection and pathogenicity for mice.

Swiss white mice immunized with acetone-killed vaccines prepared from strains of Salmonella typhosa, S. typhimurium, and mouse-virulent S. typhimurium hybrids which had acquired, by conjugal genetic transfer, the S. typhosa antigens 9, Vi, and d were challenged with the S. typhimurium hybrids and with the S. typhimurium parent strain. The results of these experiments suggested that the Salmonella somatic antigens were important in conferring protection against death in this system. The S. typhosa Vi antigen did not appear to play any significant role in this protection. The S. typhimurium hybrids employed in these studies did not show any loss of mouse virulence as the consequence of acquisition of various combinations of the S. typhosa somatic, flagella, or Vi antigens, nor did S. typhosa hybrids which had acquired the somatic antigen of S. typhimurium show any increase in mouse virulence.

Animals↗
PubMed1973

Assay of typhoid vaccines with Salmonella typhosa-Salmonella typhimurium hybrids.

Salmonella typhimurium hybrids expressing the S. typhosa antigens 9, d, and Vi were constructed by genetic crosses with an S. typhosa Hfr donor. The hybrids retained the same degree of mouse virulence as their S. typhimurium parent strain, the minimum lethal dose being less than 50 organisms when tested either in C(57) black mice or Swiss white mice. Vaccination of the Swiss white mice with S. typhosa Ty2 vaccines prepared by acetone treatment, alcohol treatment, or heat-killing conferred significant protection against challenge by the hybrid strains but not against their S. typhimurium parent. Both the acetone-treated and alcohol-treated typhoid vaccines were markedly more protective than the heat-killed, phenol-preserved vaccine.

Animals↗