Biomedical subjects
Publications and source records attributed to P Hamilton.
One hundred and seventy five recipients of a kidney graft were analyzed to see if mismatching for certain HLA-A, -B antigens was detrimental to graft survival. No association was found between graft survival and a specific mismatched HLA-A, -B antigen.
The pharmacokinetics of melphalan have been studied after intravenous and oral dosing (10 mg) in 6 patients with multiple myeloma. After intravenous administration, mean plasma t0.5 alpha was 8.0 +/- 2.3 min, t0,5 beta was 63.3 +/- 8.7 min, and total systemic clearance was 510.4 +/- 57.9 ml/min. After oral administration, the drug was rapidly absorbed (lag-time = 18.4 +/- 3.7 min, absorption rate constant = 0.0547 +/- 0.0166 min-1, Tmax = 59.3 +/- 6.6 min), but there was considerable variation in its bioavailability (61.5 - 102.0% mean 78.3 +/- 6.3%). Variability in drug absorption may be responsible, at least in part, for variation in response to this drug.
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The lysis-centrifugation technique (ISOLATOR; E. I. du Pont de Nemours & Co., Wilmington, Del.) and the radiometric blood culture technique (BACTEC; Johnston Laboratories, Inc., Cockeysville, Md.) were compared on 1,000 blood cultures. A total of 16 ml of blood was distributed: 8 ml into an ISOLATOR 7.5 microbial tube and 4 ml each into BACTEC 7C and 8B bottles. The concentrate from the ISOLATOR tubes was inoculated under a laminar-flow hood onto two sheep blood agar plates (one incubated in CO2 and one incubated anaerobically), one chocolate agar plate, and one brain heart infusion agar plate. Of 91 blood specimens obtained that yielded clinically significant organisms, 52 were positive by both systems, 27 were positive by the ISOLATOR system only, and 12 were positive by the BACTEC system only. From the positive blood specimens, 97 clinically significant organisms were isolated: 57 by both systems, 27 by the ISOLATOR system only, and 13 by the BACTEC system only. Of the 57 organisms detected by both systems, 28 were detected simultaneously, 13 were detected earlier by the ISOLATOR system, and 16 were detected earlier by the BACTEC system. Isolated colonies were obtained earlier by the ISOLATOR system in 40 cases and by the BACTEC system in 5 cases. Organisms determined to be contaminants by thorough chart review were isolated from 138 ISOLATOR tubes. In 98 instances, these were represented by one colony of Staphylococcus epidermidis, alpha-hemolytic streptococci, or diphtheroids. The ability to determine CFU per milliliter with the ISOLATOR system did not help differentiate clinically significant organisms from contaminants.
We investigated the effect of high-frequency oscillation (HFO) on lung lymphatic function under normal conditions and when lung lymph flow was increased by air microembolization. In six experiments, sheep and goats with chronic lung lymph fistulas and vascular catheters were anesthetized, paralyzed, intubated, and ventilated according to the following protocol: 1) intermittent positive-pressure ventilation (IPPV) for 1 h, 2) HFO with a frequency of 15 Hz and an estimated tidal volume of 1-2 ml/kg for 1-2 h, and 3) IPPV for 0.5 h. Ventilator settings were adjusted to maintain arterial Po2 above 100 Torr and a normal arterial Pco2. Vascular, esophageal, and mean airway pressures were monitored continuously. Lymph flow and cardiac output were recorded every 15 min. With this protocol, there were no changes in pulmonary vascular or esophageal pressures, and lymph flow remained stable throughout the experiment. In an additional five experiments, air microemboli were infused for approximately 30 min during HFO. Left atrial pressure was unchanged and lymph flow tripled. This response was qualitatively and quantitatively similar to that previously reported for unanesthetized spontaneously breathing sheep. We conclude that HFO does not impair lymphatic function under resting conditions and that lymphatics retain their ability to increase water and protein clearance during HFO.
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Reasons for an increase in maximal O2 consumption (VO2max) following blood reinfusion remain unclear; thus the present investigation was undertaken to examine the arterial and femoral venous blood gases during submaximal and maximal exercise. Four untrained males (22-25 yr) performed modified Balke work capacity tests under control conditions (Hct = 42.4 +/- 0.8%; Hb = 14.7 +/- 0.5 g X 100 ml-1) and following autologous blood reinfusion (Hct = 46.2 +/- 1.3%; Hb = 16.4 +/- 0.9 g X 100 ml-1). VO2 was determined by open-circuit spirometry and cardiac output by the N2O method; radial arterial and deep femoral venous blood were sampled at each work load throughout the incremental work tests. Following blood reinfusion, subjects' VO2max increased (P less than 0.05) from 4.0 (in control) to 4.5 1 X min-1. Throughout submaximal exercise arterial PO2 remained relatively constant (between 80.1 +/- 4.4 and 89.1 +/- 5.0 Torr) and cardiac output unchanged, comparing the two experimental conditions. Femoral venous PO2 values were almost identical throughout the work capacity tests, declining at exhaustion to 15.7 +/- 1.5 Torr in control and to 13.8 +/- 3.3 Torr postreinfusion. It appeared that the subjects' increase in VO2max postreinfusion was due to an increased O2 supplied to the tissue [i.e., cardiac output (Q) X arterial O2 content (CaO2)] by the central circulation. This resulted from a small (10%) increase in Q and a constant elevation in CaO2 of 1.7-2.2 ml X 100 ml-1, since virtually no changes were observed in the femoral venous blood postreinfusion and the acid-base status and temperature, important determinant of O2 dissociation, were (almost) identical, comparing the two experimental conditions.
A case of multiple Brenner tumors was studied with light and electron microscopy. Among the epithelial elements, argyrophil cells were found in addition to the typical "transitional" and mucus-secreting cells. In some areas, it was not possible to distinguish epithelial from tumor stromal cells. By electron microscopy, dense-core secretory granules were identified, as well as previously undescribed cytoplasmic tubular bodies. Some epithelial cells were intimately associated with reticulin and collagen. Some stromal cells had desmosomes, dense bodies, incomplete basal lamina, and, occasionally, multivesicular bodies, which suggests epithelial differentiation. Previous authors have documented morphologic similarities and continuity between Brenner-tumor epithelium and ovarian cells of almost every type. The inference is that there are multiple possible sources for the Brenner tumor. Classification must therefore be based on realize differentiation rather than presumed cell of origin.
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This manuscript assesses the outcome of a dental educational program in relation to institutional goals and program objectives. The study, covering the total population of 841 graduates of a dental school from 1972 through 1978, focused on the first classes to complete a significantly revised curriculum. The data identified specific characteristics such as (1) the distribution of dental practices, (2) general practices versus specialization, (3) solo vis-s-vis multiple or group practices, (4) residency training and advanced education, (5) faculty positions, (6) publications and research, (7) hospital affiliations, and (8) community activities. A pattern of responses developed that appears to indicate that those outcomes noted above, when combined with end-of-course and licensure examinations, supports an assumption of achievement of program objectives and institutional goals.
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Studies were performed at rest and during exercise of varied intensity on 52 boys of pre- and post-pubescent age. Each age group consisted of boys who were engaged in a strenuous prolonged hockey training program; this group was compared with a matched control group who did not participate in a regular training program. Any differences observed in the measured lung functions could be explained on the basis of physical size. Relationship of pulmonary capillary blood flow (Qc) and pulmonary diffusing capacity (DLco) to oxygen consumption were similar to those reported for adults and no difference between the trained and control groups was found in either the pre- or post-pubertal aged boys. Similarily, the trained pre-pubertal boys did not differ significantly from their matched control group in respect to the relationships of heart rate (HR) and stroke volume (SV) for any level of oxygen consumption. In contrast, the post-pubertal trained boys had significantly lower HR and higher SV (P less than 0.01) at each level of work than the control group. These differences between the trained and control post-pubertal boys are consistent with training effects observed in adults. The lack of differences between the trained and control pre-pubertal groups was surprising. Whether the differences in the post-pubertal groups due to a detraining effect in the post-pubertal control boys (as compared to the pre-pubertal control group) or to a continued high level of physical activity during and after the on-set of puberty in trained boys cannot be answered by this study. The findings suggest the importance of high intensity exercise programs during the growth period of adolescence if the efficiency of the oxygen delivery system, and possibly its ultimate dimensions, are to be enhanced.
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