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Biomedical subjects

R R Howard

Publications and source records attributed to R R Howard.

13 recordsLinked to original sources
PubMed1996

Reference intervals of CD3, CD4, CD8, CD4/CD8, and absolute CD4 values in Asian and Non-Asian populations.

A study to determine reference intervals in normal Asian and non-Asian populations for CD3 (T cells), CD4 (T helper/inducer cells), CD8 (T suppressor/cytotoxic cells), and for the CD4/CD8 ratio and absolute CD4 lymphocyte count was performed. Coulter Clone/Cytostat reagents were used. The samples were lysed using the Coulter Q-Prep and analyzed on the Coulter Profile II flow cytometer. The Asian population appeared to have a lower mean percentage of CD3 and CD4 cells, a lower CD4/CD8 ratio, and lower absolute CD4 lymphocytes. These findings indicate that race should be a consideration in determining reference intervals for immunophenotyping for CD3, CD4, and CD8.

Adult↗
PubMed1994

DNA content of head and neck squamous carcinoma by flow and image cytometry.

OBJECTIVE: To compare the measurement of quantitative DNA in squamous cell carcinoma of the head and neck by flow cytometry and image cytometry. DESIGN: Comparison of image cytometry to the more commonly used flow cytometry using paraffin-embedded tissues. SETTING: University of California, Davis Medical Center, Sacramento. A 472-bed university teaching hospital. PATIENTS: Records of 26 patients with squamous cell carcinoma of the tongue, base of tongue, and larynx were obtained from the case files of an otolaryngologist-head and neck surgeon. They were reviewed for staging and follow-up. RESULTS: We demonstrated a 96% concordance rate between the methods. A solitary discrepant case was aneuploid by image cytometry and diploid by flow cytometry. The specimen involved tumor infiltrated by lymphocytes that may have masked the aneuploid population to measurement by flow cytometry. Quantitative DNA analysis correlated moderately well with tumor grade, tumor stage, and patient outcome with a minimum of 6 years of follow-up. All patients with diploid tumors were long-term survivors. CONCLUSIONS: Both methods provide accurate quantitative DNA analyses in squamous cell carcinoma of the head and neck. The methods are highly correlative and yield similar predictive data regarding tumor behavior and prognosis.

Carcinoma, Squamous Cell↗
PubMed1992

Concurrent experimentally induced infection with Eimeria bovis and coronavirus in unweaned dairy calves.

Over a period of 3 summers, 21 colostrum-fed Holstein bull calves, 1 to 3 days old, were assigned to 7 replicates, each consisting of 3 calves. Within each replicate of 3 calves, 2 were selected at random, to be given 100,000 to 146,000 sporulated coccidia oocysts (principally Eimeria bovis) orally 60 hours after arrival at the college research farm. On the thirteenth day after coccidia inoculation, 1 of the 2 calves that had been given coccidia and the third calf that had not been inoculated, were given coronavirus by intranasal and oral routes. Calves were observed daily, and consistency of feces was scored visually. Nasal swab specimens for indirect immunofluorescent antibody testing for coronavirus and fecal samples for oocyst determination were obtained approximately every third day. Of 7 calves that were given only coronavirus, 3 developed diarrhea of short duration. Of 7 calves that were given only coccidia oocysts, 6 developed diarrhea. All 7 calves inoculated initially with coccidia and subsequently with coronavirus developed diarrhea. For 5 of 7 replicates, calves that were given coccidia and coronavirus developed diarrhea first. When overall severity, measured by fecal score and by blood in the feces, was compared, calves inoculated with coccidia followed by coronavirus were more severely affected (P less than 0.05) than were calves that were given only coronavirus. Calves that were given only coccidia oocysts appeared more severely affected than calves that were given only coronavirus, but differences were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Severe head injury: effect upon cellular immune function.

Infection is a major cause of morbidity following severe head injury. Although investigations have demonstrated central nervous system modulation of immune function, the effects of severe head injury on immune activity have not been well documented. This study prospectively investigated cellular immune function in 20 patients with isolated severe head injury. In vivo cellular immune status was determined by responses to delayed-type hypersensitivity (DTH) skin tests. In vitro studies included the effect of the lymphocyte mitogen, phytohaemagglutinin (PHA), on peripheral blood lymphocyte (PBL) phenotype expression and PBL blastogenesis. DTH skin testing demonstrated anergy to all antigens used during the first two weeks following head injury. Analysis of PBLs incubated with PHA demonstrated a decrease in the percent of PBL blastogenesis (p = 0.002), the percentage of cells marking as T-cells (p = 0.018), helper T-cells (p less than 0.001) and those expressing interleukin-2 receptors (p less than 0.001). There was a significant increase in the percentage of cells that marked as monocytes (p = 0.030), whereas there was no significant change in the percentage of B-cells, suppressor/cytotoxic T-cells, natural killer cells or in cells expressing the HLA-DR antigen. The infection rate was 55% with most occurring within 5 days of injury. The results of this study suggest that isolated severe head injury causes suppression of cellular immunity. The decrease in PHA stimulated PBL blastogenesis, helper T-cell phenotypic and interleukin-2 receptor expression, suggests suppression in early helper T-cell activation may be responsible for the high incidence of infection following severe head injury. The possible significance of increased monocyte phenotypic expression is discussed.

Adolescent↗
PubMed1989

Evaluation of lasalocid and decoquinate against coccidiosis resulting from natural exposure in weaned dairy calves.

Eighteen female Holstein calves, raised as natural herd additions under conditions typical of a well-managed midwestern United States dairy farm, were used in a natural-exposure study to determine the anticoccidial efficacies of lasalocid and decoquinate. Calves were allotted to 6 treatment blocks of 3 calves each as they were weaned. Within each block, calves were randomly assigned to be given either lasalocid or decoquinate or to remain as a nonmedicated control. Calves were given medication for 90 days and remained separated from other calves for 120 days. Adjusted weight gains were consistently greater in calves that were given medication; however, differences were not statistically significant. Fecal specimens were obtained from calves at weekly intervals during the study. Overall, oocyst shedding was low. During the medication period, quantitative mean fecal shedding of oocysts was reduced eightfold in calves given decoquinate and four-fold in calves given lasalocid, as compared with nonmedicated control calves. During the period following the medication period, calves that had been controls shed fewer oocysts than did calves that had previously been given medication. A pairwise comparison of the proportion of specimens that were oocyst-positive was made to assess qualitative oocyst shedding among treatment groups. During the medication period, qualitative oocyst shedding (all species, Eimeria bovis, E zuernii, species other than E bovis and E zuernii) was greater in controls than in either lasalocid-or decoquinate-treated groups. Like-wise, lasalocid-medicated calves shed oocysts more frequently than did the decoquinate-medicated group. After medication, qualitative findings were reversed. Little diarrhea was noticed in treatment or control calves during the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗