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Biomedical subjects

R D Walker

Publications and source records attributed to R D Walker.

At least 163 records · Page 9Linked to original sources
PubMed1984

Growth phase-dependent phagocytosis of Pasteurella haemolytica by bovine pulmonary macrophages.

The ability of the bovine pulmonary macrophage (PM) to phagocytize Pasteurella haemolytica in its logarithmic and declining phases of growth was characterized. Pulmonary macrophages were harvested from bovine lungs before and after their in vivo exposure to P haemolytica. The PM from each lavage period phagocytized P haemolytica in the declining phase of growth. However, P haemolytica in the log phase of growth was not phagocytized by PM from any of the lavage periods. Instead, PM exposed to P haemolytica in the log phase of growth had altered cellular morphologic features and were cytolytic. Pasteurella haemolytica in the log phase also inhibited phagocytosis of Saccharomyces cerevisiae by PM. This inhibition of phagocytosis, as well as morphologic alterations, was evident in PM cultures exposed to P haemolytica for less than 1 minute.

Animals↗
PubMed1983

Death of an African elephant from probable toxemia attributed to chronic pulpitis.

A 31-year-old captive male African elephant (Loxodonta africana) of 5,000-kg body weight died suddenly in ventral recumbency. Lesions seen at necropsy were bilateral purulent pulpitis and periodontitis of both tusks, serous atrophy of coronary groove fat, Grammocephalus cholangitis, myocardial and skeletal lipofuscinosis, and scattered segmental necrosis in the pectoral muscles. Nonhemolytic streptococci, Corynebacterium sp, Peptostreptococcus anaerobius, Fusobacterium nucleatum, and Bacteroides sp, were recovered from the exudate around one or both tusks. We postulated that the elephant died of hypoxia from prolonged ventral recumbency because of weakness and inability to rise secondary to toxemia from bilateral pulpitis and periodontitis.

Animals↗
PubMed1983

Anaerobic bacteria associated with osteomyelitis in domestic animals.

Specimens of bony tissue or adjacent soft tissue from 19 animals with osteomyelitis were cultured aerobically and anaerobically. Fourteen specimens (74%) yielded anaerobic bacteria in pure culture or mixed with aerobic or facultative anaerobic bacteria. The most predominant genus encountered was an obligate anaerobe, Bacteroides. The most frequently isolated Bacteroides species was Bacteroides asaccharolyticus, which was isolated 5 times. The most frequently isolated anaerobe was Peptostreptococcus anaerobius, which was isolated 6 times. Staphylococcus aureus and Escherichia coli were the most frequently isolated aerobic bacteria, with 7 and 6 isolates, respectively.

Animals↗
PubMed1983

Predictors of relapse: interaction of drinking-related locus of control and reasons for drinking.

Pretreatment scores from the drinking-related locus of control scale (DRIE) and reasons for drinking were investigated as predictors of drinking relapse over a nine-month follow-up in a sample of 232 male alcoholics. A significant relationship was found between reasons for drinking and the probability of relapse, with the lowest relapse rates occurring among patients who identified interpersonal conflicts or positive emotional states as the most important reasons for their pretreatment drinking. Results of a reasons for drinking by relapse status ANOVA on DRIE scores revealed no significant main effects. There was, however, a significant interaction. Among patients who attributed their drinking to negative emotional states, those who either relapsed or were lost to follow-up had significantly more external DRIE scores. Among patients who identified negative physical states (i.e., craving) as their primary reason for drinking, relapse or attrition was associated with significantly more internal DRIE scores. Results support assessment of these cognitive social learning constructs for differential treatment planning with patients at increased risk of relapse.

Alcohol Drinking↗
PubMed1983

Exploration of the relationship between frequency of illness, attrition from alcohol treatment, neuropsychological status and field dependence.

One hundred thirty-nine male veterans receiving treatment for alcoholism were administered the Cornell Medical Index (CMI), neuropsychological tests comprising the Brain Age Quotient (BAQ) and the Group Embedded Figures Test (GEFT). Patients endorsing items on scale J (frequency of illness) of the CMI comprised a frequently ill group (27%) with the remaining patients comprising an infrequently ill group (73%). The frequently ill group patients were more likely to drop out of treatment, obtain lower BAQ scores and appear more field-dependent on the GEFT. Treatment attrition of frequently ill patients might be less if their individualized treatment plan involved greater structure consistent with their field dependent orientation and impaired neuropsychological status.

Adult↗
PubMed1983

Megalourethra and hypospadias.

We compared clinically 11 patients with megalourethra and hypospadias as well as 2 additional patients previously reported on in the literature to patients with either hypospadias or megalourethra alone. The milder presentation of patients with megalourethra and hypospadias, and the ease of satisfactory repair indicate that they represent a less severe variant of classic megalourethra.

Humans↗
PubMed1983

Renal growth and scarring in kidneys with reflux and a concentrating defect.

A study was done to determine if kidneys with reflux and an associated renal concentrating defect grew less well and had more scars than kidneys with reflux but no renal concentrating defect. To test our hypothesis we measured renal growth and assessed radiographs for renal scars in 11 children with and 20 children without a renal concentrating defect. Kidneys with reflux and a renal concentrating defect grew less well and had more scars than those kidneys with reflux but no renal concentrating defect. A persistent renal concentrating defect may be a predictor of kidneys more likely to have impaired growth and renal scars.

Child↗
PubMed1983

Visceral protein status of patients hospitalized for alcoholism.

The purpose of this study was to evaluate the nutritional status of patients hospitalized for alcoholic rehabilitation. It was hypothesized that thyroxine-binding prealbumin, due to its shorter half-life, would be more sensitive to poor nutritional status than other visceral proteins. Extensive biochemical, anthropometric, and nutrient intake data were obtained on hospital days 2, 7, and 14. No abnormalities in visceral protein status initially, or with time, were seen in this population. The principal conclusion is that severe nutritional deficiencies are not prevalent in this patient sample hospitalized for alcoholic rehabilitation.

Adult↗
PubMed1983

Hydrogen-1 and carbon-13 nuclear magnetic resonance conformational studies of the His-Pro peptide bond: conformational behavior of TRH.

Cis/trans isomerism of the His-Pro peptide bond provides a convenient model for the effect of a slow conformational change which may have wider biological significance. Above the imidazole pK, His-Pro is conformationally analogous to the (isosteric) peptide Phe-Pro. Protonation of the imidazole sidechain is associated with a large decrease in the cis/trans ratio. Detailed 1H and 13C n.m.r. analysis suggests the importance of electrostatic/hydrogen bonding interactions between the charged imidazolium sidechain and the proline carboxyl as the basis for this effect. In contrast to a previous report, cis/trans isomerism in TRH is shown to be related to titration of the imidazole sidechain, exhibiting a pK of 6.1.

Dipeptides↗
PubMed1983

Complications of ureteral duplication surgery.

The complications associated with surgery of duplex collecting systems are difficult to manage, and multiple options for reconstruction are available. Successful correction is based on an assessment of the anatomy and function in the kidney draining the complicated segment and on assessment of the remaining ureteral tissue. Many times successful reconstruction requires an innovative approach.

Child↗
PubMed1982

Renal ultrasound in the neonatal period.

Ultrasound was used for imaging the kidneys in 55 neonates. The normal kidney in a neonate is characterized by prominent medulla and fetal lobulation, the main renal vessels are frequently demonstrated. Of 29 infants with normal kidneys by ultrasound, 4 had renal disease (3 acute tubular necrosis, one partial renal artery thrombosis) and one had a pelvic kidney. In 24 infants congenital abnormalities or acquired renal disease was diagnosed. Multicystic dysplastic kidney and hydronephrosis were the most frequently observed abnormalities. Polycystic kidneys at the early stage (both adult type and infantile) appeared as enlarged hyperechoic kidneys. In 2 neonates the kidneys were normal but they had adrenal mass lesions.

Diagnosis, Differential↗
PubMed1982

Compensatory renal growth and function in postnephrectomized patients with Wilms tumor.

The objective of this study was to determine whether or not renal growth and function were adversely affected in the remaining kidneys of patients who had undergone nephrectomy for Wilms tumor. These patients received chemotherapy and some radiotherapy (tumoricidal agents which might affect the remaining kidney). Renal growth was compared between the treatment groups and normal renal growth. Hypertrophy did occur and did not appear to be affected by subsequent treatment. Renal function was minimally altered in all treatment groups irrespective of the type of treatment.

Adaptation, Physiological↗
PubMed1982

Further investigations of mutagenic cholesterol preparations.

The previously demonstrated mutagenicity of naturally air-aged (autoxidized) USP cholesterol in test strains of Salmonella typhimurium has been confirmed. In contrast, autoxidized brassicasterol, 7-dehydrocholesterol, ergosterol, lanosterol, sitosterol, and stigmasterol were non-mutagenic in the same assay, and 38 individual cholesterol derivatives, including many cholesterol autoxidation products, were also non-mutagenic. The mutagenic species from mutagenic cholesterol preparations were shown to be neutral steroids that are very much more polar than the cholesterol autoxidation products so far identified. High-performance liquid chromatography resolved mutagenic cholesterol preparations into several mutagenic and non-mutagenic fractions. The chemical nature of the mutagens is suggested as involving oxidation of the sterol B-ring and of the side-chain.

Cholesterol↗
PubMed1982

Differential drinking patterns, personality characteristics, and field articulation of court-referred and non-court-referred male alcoholics in treatment.

Male alcoholics in an inpatient rehabilitation program were selected to investigate differential characteristics of court-referred patients on measures of personality, drinking style, demograhics, and cognitive style. Seventy-eight males were separated into two groups based upon the demographic dimension of whether or not the patient was in treatment primarily as a result of legal pressures imposed due to alcohol-related motor vehicle violation (N = 23) or in treatment for a variety of personal/nonlegal reasons (N = 57). All subjects were administered the Clinical Analysis Questionnaire (CAQ), the Alcohol Use Inventory (AUI), and the Group Embedded Figures Test (GEFT). There were no differences found on any of the personality or demographic measures. There were significant differences between the legal and nonlegal groups on 11 of the 20 AUI scales. The legal group tended to be more field dependent than the nonlegal group as measured by the GEFT. The legal group does not appear to suffer as severely from the effects of alcohol as does the nonlegal group and may be in an earlier stage of problem drinking.

Adult↗