Cost versus care.
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Delivery of Health Care↗
Biomedical subjects
L S Anderson
Publications and source records attributed to L S Anderson.
The choice is ours. Ethical actions under managed care.
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Ethics, Medical↗
Synthesis of a photoaffinity analog of 3'-azidothymidine, 5-azido-3'-azido-2',3'-dideoxyuridine. Interactions with herpesvirus thymidine kinase and cellular enzymes.
Long term administration of 3'-azidothymidine (AZT) for the treatment of AIDS has led to detrimental clinical side effects in some patients, the biochemical causes of which are still being delineated. Base-substituted, azido-nucleotide photoaffinity analogs have routinely proven to be effective tools for identifying and characterizing nucleotide-utilizing enzymes. Therefore, we have synthesized 5-azido-3'-azido-2',3'-dideoxyuridine, which is a potential photoaffinity analog of two human immunodeficiency virus drugs, AZT and 3'azido-2',3'-dideoxyuridine. A partially purified herpes simplex virus type 1 thymidine kinase and [gamma-32P]ATP were used to make an AZT monophosphate analog, [32P]5-azido-3'-azido-2',3'-dideoxyuridine monophosphate. The photoaffinity properties of this analog were initially tested with herpes simplex virus type 1 thymidine kinase. Photoaffinity labeling of this enzyme was saturable (half-maximal, 30 microM) and could be specifically inhibited by AZT, AZT monophosphate, thymidine, and thymidine monophosphate. Photolabeling of rat liver microsomal membranes was also done, and several membrane proteins that interact with AZT monophosphate were identified. The antiviral and cytotoxic activities of 5-azido-3'-azido-2',3'-dideoxyuridine were determined using human immunodeficiency virus, type 1 strain IIIB and an AZT drug-resistant strain in human T lymphocyte H9 cells.
Affinity Labels↗
Comparative analyses of peritoneal fluid from calves and adult cattle.
Reference values for hematologic variables change with increasing age in cattle. Therefore, the purpose of the study reported here was to describe the peritoneal fluid constituents of clinically normal young calves, and to compare cellular concentration and distribution in blood and peritoneal fluid of young calves with those of adult cattle. Eight healthy 8-week-old male Holstein calves and 8 healthy 3- to 8-year-old Holstein cows were studied. Peritoneal fluid was collected from calves along the ventral midline, 4-cm cranial to the umbilicus. Abdominocentesis was performed in the region of the lower right flank in adult cattle. Correlation analysis, using the Pearson's correlation coefficient, and regression analysis were performed for blood and peritoneal fluid data from calves. Data from calves were compared with those of cows, using Wilcoxon's rank sum test. A P value < 0.05 was considered significant for all tests. Calves had significantly lower blood eosinophil count (P < 0.003) and plasma protein concentration (P < 0.001) than did cows. Calves had significantly higher peritoneal fluid nucleated cell (P < 0.05) and mononuclear cell (P < 0.05) counts, but lower peritoneal fluid eosinophil cell count (P < 0.003) than did cows. For calves, nucleated cell and lymphocyte cell counts in the blood had a high, positive correlation with those of peritoneal fluid. However, the prediction equation for nucleated cell count accounted for a modest proportion of variability. A prediction equation for peritoneal fluid lymphocyte cell count was established.(ABSTRACT TRUNCATED AT 250 WORDS)
Aging↗
An algorithm to describe the oxygen equilibrium curve for the thoroughbred racehorse.
An algorithm to describe the oxygen equilibrium curve (OEC) of the Thoroughbred horse was derived from raw oxygen equilibrium curve data obtained under standard conditions of temperature, pH and PCO2 (Smale and Butler, 1994). This algorithm was derived by a curve-fitting procedure based on the algorithm for human blood produced by Kelman (1966). The temperature, fixed acid and net CO2 coefficients were then incorporated in the algorithm to enable the accurate calculation of % saturation from any combination of PO2, temperature, pH and PCO2. The algorithm was checked using blood gas data obtained from in vivo treadmill exercise tests as well as a standardised breathing test whereby horses inhaled several different gas mixtures. This algorithm proved more accurate for the Thoroughbred horse than that derived by Kelman.
Algorithms↗
Comparison of peritoneal fluid analysis before and after exploratory celiotomy and omentopexy in cattle.
The effect of right paralumbar fossa exploratory celiotomy and omentopexy on peritoneal fluid constituents was studied in 22 adult dairy cows. Six cows were eliminated on the basis of physical examination findings (n = 2), surgical findings (n = 2), or inability to obtain a sufficient volume of peritoneal fluid (n = 2). Sixteen cattle had normal results of CBC and serum biochemical analysis, and a minimum of 1 ml of peritoneal fluid was obtained by abdominocentesis. Abdominocentesis was repeated on days 1, 2, and 6 after surgery. Statistical analysis for repeated measures was performed, using a significance level of P < 0.05. Stage of gestation was evaluated for interaction with time. Mean total nucleated cell count was 3,200 cells/microliters before surgery, was significantly increased 2 days after surgery (16,336 cells/microliters), and continued to increase through day 6 (20,542 cells/microliters). Mean polymorphonuclear cell count was 1,312 cells/microliters before surgery and was significantly higher at 2 (11,043 cells/microliters) and 6 (10,619 cells/microliters) days after surgery. Mean lymphocyte count was 254 cells/microliters before surgery and was significantly increased 2 days (1,911 cells/microliters) after surgery. By day 6, lymphocyte numbers were similar to preoperative values. Mean mononuclear cell count was 770 cells/microliters before surgery and was significantly increased on days 1 (3,084 cells/microliters), 2 (3,285 cells/microliters), and 6 (2,349 cells/microliters) after surgery. Mean eosinophil numbers were 1,388 cells/microliters before surgery and were significantly increased on day 6 (6,347 cells/microliters) only. Interaction between time and stage of gestation was found only for specific gravity and total protein concentration.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Stride length and respiratory tidal volume in exercising thoroughbred horses.
The purpose of this study was to test the hypothesis that locomotor-respiratory coupling in horses may provide a basis for the appropriate matching of lung ventilation to running speed and metabolic power. This was achieved by determining the effect on respiratory frequency and tidal volume in thoroughbred horses of changing running speed while maintaining a constant metabolic demand by also varying the incline of the treadmill. This procedure was performed at three different speeds at two different levels of metabolic rate. It appears that, in response to metabolic demands which are not directly related to speed, horses can control tidal volume independently of stride length but they do not vary respiratory frequency independently of stride frequency. When running at 0 degrees incline, however, they probably do not operate an elevated tidal volume, because of the increased energetic costs such an elevated tidal volume would incur.
Animals↗
New mechanism for disruption of axillofemoral bypass.
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Anastomosis, Surgical↗
Avoiding complications in arterial surgery.
Our approach to vascular surgery is to recognize and contemplate perioperative complications and devise strategies to avoid them. These strategies are detailed in several of the major areas of arterial surgery. It is far easier to avoid complications than to deal with them when they occur. This is especially true for some complications in vascular surgery, such as intraoperative or postoperative cerebrovascular accident, atheroembolic complications, or distal thrombosis in lower-extremity reconstruction, that may result in either irreversible morbidity or death.
Aortic Aneurysm↗
Unraveling rural EMS problems.
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Emergency Medical Services↗
Interpersonal style differences among drug abusers.
Interpersonal style differences among drug abusers were explored using Ryan's (1977) typological system of FIRO-B interpretation. One hundred eleven male veteran drug abusers were administered the FIRO-B, along with a battery of psychological tests and a structured interview. The drug abusers were more likely to be categorized as "loners," "rebels," and "pessimists" than was the general population sample. The categories within each FIRO-B dimension (inclusion, control, and affection) were collapsed into three larger subtypes based on general patterns of "expressed" and "wanted" scores within each dimension. The construct validity of the Ryan schema was tested by comparing the three larger groups for each dimension on a series of preselected variables for which differences would be hypothesized from FIRO theory. The results of these analyses were consistent with Ryan's (1977) and Schutz's (1978) theories about interpersonal orientation. The findings of the study provide information about the commonality and heterogeneity of interpersonal style among drug abusers. The findings also support the construct validity of Ryan's typological schema for the FIRO-B.
Adult↗
Increased hair growth and density following controlled expansion of guinea pig skin and soft tissue.
The goal of this study was to investigate the effect of controlled tissue expansion on hair growth and density using the guinea pig model. Thirty white guinea pigs were randomly divided into three groups: a group to undergo expansion (EXP), an operated control group (OC), and a nonoperated control group (NOC). All groups were shaved to create a 1 cm X 2 cm tuft of dorsal hair, which was subsequently dyed. Only the EXP and OC group members underwent construction of a pocket beneath the tuft. Only the EXP group was implanted and expanded over four weeks. The EXP group revealed a significant increase (p less than 0.005) over the controls in both the number of new white hairs produced (W) and density proportion (W/A). The OC group exhibited a significant increase (p less than 0.005) over the NOC group in both W and W/A. Mechanisms to explain the results are postulated. These include the possible roles of increased follicular mitotic activity (hair follicle transformation and cycle dynamics) and improved perifollicular vascularity (capsule formation and the delay phenomenon of skin pocket construction). Clinical implications are discussed.
Animals↗
Rhegmatogenous retinal detachment in angiomatosis retinae.
Three patients with von Hippel tumors of the retina developed rhegmatogenous retinal detachments caused by surface traction on the angioma. The break in each case was located at the posterior base of the angioma, between the afferent and efferent vessels. Conventional scleral buckling surgery with cryotherapy and a silicone episcleral sponge successfully reattached the retina in all three cases.
Adolescent↗
Respiratory responses of the domestic fowl to low level carbon dioxide exposure.
Respiratory function in the restrained, conscious domestic fowl was measured using a non-invasive technique and computer aided analysis to examine respiratory flow, and in-dwelling arterial catheters to monitor blood carbon dioxide levels. The effects of two low ranges of inspiratory carbon dioxide (0.2 to 1.0 per cent and 0.25 to 2.25 per cent) were studied, simulating levels of carbon dioxide that may occur in commercial poultry units and representing a mild environmental stress for the birds. A linear increase in minute volume with inspiratory carbon dioxide was observed, due primarily to increases in tidal volume. Arterial carbon dioxide (PaCO2) tension also rose as the inspiratory carbon dioxide concentration was raised, but higher inspiratory carbon dioxide levels were required to affect significantly blood carbon dioxide concentration than to modify respiratory parameters. Variation was observed in the individual bird's response to carbon dioxide (bird X carbon dioxide interaction), suggesting that resting values of the respiratory parameters measured were important in determining the bird's ventilatory response to carbon dioxide.
Analysis of Variance↗
Variability in respiratory function of the domestic fowl.
Several respiratory parameters were measured in five groups of hens to estimate the variation in respiratory function of the general hen population. A non-invasive technique was used to measure respiratory flow, with computer-aided analysis of the data, and the results were examined statistically. Using different groups of hens, additional information was obtained regarding possible sources of variation between individual hens, such as egg laying condition, age and health. Significant differences between individuals within the groups were observed, but there were also changes in breath-to-breath variation for individual hens. While some changes in the variation between birds were observed from one group to another, variation within individual birds made interpretation of the results difficult. Repeated measurements made on one group revealed significant changes in minute volume with time, but the changes were not related to learning. Significant interactions between hens and time of measurement occurred for certain parameters, showing that the individuals' responses changed with time in different ways. The groups of hens were compared to observe whether they represented the same or distinct populations, and were found to overlap to varying extents for different respiratory parameters. Single respiratory variables and weighted combinations of certain variables were also used to separate the groupings, as a possible diagnostic method for partitioning groups of hens.
Animals↗
Ventilatory and cardiovascular responses of the unanaesthetized chicken, Gallus domesticus, to the respiratory stimulants etamiphylline and almitrine.
The ventilatory and cardiovascular effects of i.v. administration of the respiratory stimulants etamiphylline and almitrine were investigated in conscious or decerebrate adult female domestic fowl. Infusion of etamiphylline (100 mg . kg-1) or injection of almitrine (2 mg . kg-1) evoked a potent long-lasting stimulation of ventilation in both conscious and decerebrate fowl. The pattern of the respiratory response was characteristically different to that observed in mammals in that the increased minute volume of ventilation was attained by large increases in respiratory frequency accompanied by a reduction in tidal volume. The pattern of respiration following drug-induced stimulation was, in some birds, typical of thermal panting although neither etamiphylline nor almitrine caused significant increases in body temperature. Differences in the pattern of responses of the rate and depth of breathing may be attributed in part to the differences in pulmonary receptor systems involved in the control of breathing in birds and mammals.
Almitrine↗
Notes on the linkage between the sexually abused child and the suicidal adolescent.
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Adolescent↗
Focal choroidal calcification.
Localized choroidal calcification was detected clinically in two otherwise healthy men. The lesions showed typical features of choroidal nevi. One patient exhibited features suggesting a drusen overlying the nevus. Echography detected choroidal calcification in both cases. A-scan echography revealed a highly reflective choroidal mass attenuating the ultrasound beam. B-scan ultrasonography revealed a dense choroidal mass attenuating the ultrasound beam with focal echoes remaining at low sensitivity. Orbital radiographic and CT scan examination confirmed the echographic findings.
Adult↗