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Biomedical subjects

D A Wilson

Publications and source records attributed to D A Wilson.

At least 199 records · Page 11Linked to original sources
PubMed1981

Vasoactive intestinal polypeptide and the canine cerebral circulation.

A potential role for cerebrovascular nerves containing vasoactive intestinal polypeptide (VIP) was examined in 24 anesthetized, ventilated dogs. Cerebral blood flow (CBF) was measured by either the cerebral venous outflow or microsphere method. Plasma VIP concentration was measured by radioimmunoassay. Hypercapnia (5% and 10% CO2) and hypoxia (7% O2) produced significant increases in cerebral venous outflow, but had no affect on arterial or cerebral venous VIP concentrations. Measurements of VIP in cerebrospinal fluid (CSF) made during 5% and 8% CO2 breathing also were not different from control values. VIP produced large dose-dependent increases in common carotid artery and temporalis muscle blood flow when injected or infused intraarterially; however, VIP had no effect on total or regional cerebral blood flow (rCBF) within the brain when administered in a similar manner. Unilateral perfusion of the cerebral ventricles with VIP produced significant increases (range: 11-80%) in rCBF. These data are consistent with the possibility that local release of VIP from perivascular nerve endings could affect CBF. The unresponsiveness of canine cerebral vessels to blood-borne VIP may be due to the blood-brain barrier, since VIP dilates cerebral vessels when the barrier is bypassed by intraventricular infusion. These studies do not support the hypothesis that CBF changes induced during hypercapnia or hypoxia are mediated by VIP.

Animals↗
PubMed1981

Experimental study of high-resolution ultrasound imaging of hemorrhage, bone fragments, and foreign bodies in head trauma.

The accuracy of high-resolution ultrasound scans in detecting foreign bodies and hemorrhage within the brain was evaluated by comparison with computerized tomography (CT) scans and gross pathology. The test lesions were blood and foreign bodies consisting of bone, wood, and metal placed in the brain of an experimental animal. High-resolution ultrasound scans (10 MHz) performed in coronal and sagittal planes accurately delineated the position and spatial orientation of these foreign bodies and hemorrhage. Both hemorrhage and foreign bodies were echogenic compared to normal, hypoechoic brain parenchyma. Metal fragments had a highly characteristic echo pattern caused by sound reverberation within the object. Acute intracerebral hemorrhage produced an ultrasound image consisting of sharply circumscribed homogeneous echoes. The sonographic shape of intracerebral hemorrhage correlated closely with the area of increased density seen on the CT scan. High-resolution ultrasonography accurately delineated experimentally produced components of head trauma and may prove useful as an intraoperative imaging technique to facilitate surgery in head-injured patients.

Animals↗
PubMed1981

Thymic gallium-67 localization in pediatric patients on chemotherapy: concise communication.

Localization of Ga-67 in the thymus has been reported to occur in children. In our control group of 87 patients, 15% of children under 5 yr and 11% of children over 5 yr demonstrated thymic localization. In contrast, in our study group of seven children with acute lymphocytic leukemia or malignant lymphoma, lymphocytic diffuse, treated on a modified non-Hodgkin's lymphoma protocol, Sloan-Kettering LSA2-L2, thymic localization occurred during treatment in five of the seven. We conclude that increased thymic gallium localization in children under chemotherapy for a known malignancy may reflect increased activity of thymic medullary epithelial cells and regeneration of thymic lymphocytes during recovery form involution induced by certain chemotherapeutic agents.

Adolescent↗
PubMed1979

Echocardiographic findings in a fatal case of Kawasaki's disease.

Kawasaki's disease or mucocutaneous lymph node syndrome is being diagnosed with increasing freqency in this country. Although death is a rare complication coronary arteritis with associated myocardial changes is common. Echocardiography is proposed as a non-invasive study that may aid in the early detection of cardiac involvement.

Child, Preschool↗
PubMed1979

The recovery period following exposure of bacteria to penicillins.

Experiments with Staphylococcus aureus and Streptococcus pyogenes have shown that when cells are exposed to bactericidal concentration of benzylpenicillin or ampicillin and the antibiotic then inactivated with beta-lactamase the count of the surviving viable cells (colony-forming units) remains essentially constant for a period of approximately 1.5--3 h before increasing at a normal rate. No such recovery period was observed, however, when Escherichia coli or Proteus mirabilis was exposed to a bactericidal concentration of ampicillin and the antibiotic then inactivated. Microscopic observation of individual surviving cells of S. aureus following exposure to benzylpenicillin showed that in some cases resumption of cell division was delayed as long as 4 h. However, other cells in the same population showed no recovery period and resumed division within 30 min of inactivation of the antibiotic. In the latter case, the recovery period which is observed in terms of viable count may represent the period of time required for individual surviving cells to divide and give rise to normal aggregates before these fragment to produce new colony-forming units.

Ampicillin↗
PubMed1979

Growth of Trichophyton mentagrophytes on individual amino acids.

Trichophyton mentagrophytes was tested for its ability to utilize individual amino acids as a source of carbon and nitrogen in basal medium containing 0.4 mM magnesium sulphate (0.1 g/l) in 0.05 M potassium phosphate buffer at pH6.5. Growth was quantitated by measurement of both dry weight and fungal protein. Seventeen naturally occurring amino acids supported growth, serving as a source of both carbon and nitrogen. Seven amino acids failed to support growth under these conditions; however three of these could be metabolized for nitrogen, but not for carbon.

Amino Acids↗
PubMed1978

Ultrasound and nuclear medicine in evaluation of renal disease.

Multiple diagnostic imaging techniques are currently available to the clinician but the complementary nature of these techniques is frequently overlooked. A case is presented to illustrate the contributions of ultrasound, radiology, and nuclear medicine in evaluating renal disease.

Adult↗
PubMed1978

Treatment of otitis media caused by Hemophilus influenzae: evaluation of three antimicrobial regimens.

Ninety young children with otitis media, proven by tympanocentesis culture to be due to Hemophilus influenzae, were treated in a prospective double-blind study with one of three antimicrobial regimens: ampicillin, erythromycin ethylsuccinate, or erythromycin ethylsuccinate with concomitant trisulfapyrimidines. Results of efficacy evaluation indicated that the combination was as effective as ampicillin and statistically superior to erythromycine alone. Of the strains of H influenzae identified, 15/9 were typable with 12/9, type b. In vitro sensitivity tests indicated that the strains were sensitive to the amtimicrobials studied in clinically attainable levels; however, comparison of individual efficacy ratings with sensitivity results indicated that some children in each treatment group failed to respond as predicted.

Ampicillin↗
PubMed1978

Ultrasound diagnosis of hydrocolpos and hydrometrocolpos.

Two neonates, one with hydrocolpos and one with hydrometrocolpos, were studied with ultrasound. In each case a primarily cystic abdominal mass arose from the pelvis but contained internal echoes. It is concluded that ultrasound evaluation of these disorders should aid in the preoperative diagnosis.

Female↗