Erratum: Dilute spin glass at zero temperature in general dimension
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Journal Article↗
Biomedical subjects
L Klein
Publications and source records attributed to L Klein.
Series expansions for the Ising spin glass in general dimension.
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Journal Article↗
Incidence and prevalence of human immunodeficiency virus infection in a prenatal population undergoing routine voluntary human immunodeficiency virus screening, July 1987 to June 1990.
To characterize the epidemiologic characteristics of human immunodeficiency virus type 1 infection in an urban prenatal population in the southeastern United States, we conducted serial routine voluntary antenatal human immunodeficiency virus antibody testing and obtained self-reported human immunodeficiency virus risk behavior profiles on women registering for prenatal care. From July 1987 to June 1990, 23,432 women registered for prenatal care. The majority of women (95%) consented to human immunodeficiency virus antibody testing and completed risk behavior profiles. The cumulative incidence of human immunodeficiency virus infection increased from 3.5 per 1000 in 1987 and 1988 to 5.3 per 1000 in 1989 and 1990. A history of "crack" cocaine use emerged as a significant risk factor for infection (p less than 0.01). The majority (70%) of human immunodeficiency virus-infected women did not self-acknowledge risk factors for infection and would not have been identified if screening had been targeted. The increasing incidence of human immunodeficiency virus type 1 infection in our prenatal population reinforces the need for our continued routine voluntary antenatal human immunodeficiency virus screening and risk behavior assessment.
Acquired Immunodeficiency Syndrome↗
Bone mass and comparative rates of bone resorption and formation of fibular autografts: comparison of vascular and nonvascular grafts in dogs.
The metabolic fate of whole grafts that were either vascularized or nonvascularized were compared. This study was designed to quantify and correlate changes in bone resorption, formation, and mass in orthotopic, stably fixed, weight-bearing autografts. The grafts were 8-cm segments of the fibula that were internally fixed. Fibula segments subjected to sham operations, nonvascularized autografts, and vascularized autografts were studied in 16 dogs at three months after surgery. Three months prior to surgery the dogs were labeled repeatedly over two months with 3H-tetracycline and 3H-proline. Metabolic turnover of whole grafts was evaluated by quantifying loss of 3H-tetracycline for measuring postoperative resorption of bone mineral and loss of 3H-collagen for resorption of bone collagen. Net changes in bone dry weight, calcium, and collagen per whole grafts were obtained to determine differential changes in the mineral and matrix mass. The difference in change between bone resorption and bone mass was used to determine the amount of new bone formation that had replaced the resorbed bone. Vascularized autografts lost more mass (12%), and had more bone resorption (40%) and more bone formation (28%) than sham operated and unoperated fibulas. Nonvascularized grafts lost much more bone mass (48%) because resorption was large (61%) and formation was relatively small (13%). More new bone was formed in vascularized autografts than in nonvascularized autografts. During the incorporation of bone grafts, resorption is an early and rapid process, whereas formation is a late and slow process.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Differential patterns of incorporation and remodeling among various types of bone grafts.
The early (3 months) and later (6 months) patterns of incorporation and bone formation have been evaluated histomorphometrically for different types of bone grafts; that is, vascularized and nonvascularized autografts with and without ciclosporin, and vascularized and nonvascularized dog leukocyte antigen (DLA)-mismatched allografts with and without ciclosporin. The vascularized bones were superior to the nonvascularized ones in healing and remodeling their grafted segments. In the autograft bones, ciclosporin did not alter the incorporation process 3 months after transplantation but delayed and increased the remodeling activities in the long run (6 months). Nonvascularized allografts underwent vigorous resorption, and were markedly porotic. Ciclosporin administration significantly reduced resorption and enhanced remodeling in nonvascularized allografts. The remodeling of allografts was similar to that of autografts in the presence of ciclosporin, but stopped soon after the administration of ciclosporin ceased.
Animals↗
The use of fasciocutaneous flaps on perforating vessels.
The distally based fasciocutaneous flaps on perforating vessels are mobile, well shapable and cosmetically satisfactory ones. In soft tissue defects of the lower third of the leg the above flaps should be a method of choice for their simple applicability and shapability of tissues. Pedicular fasciocutaneous flaps enable us to enlarge the possibilities of reconstructive surgery in this field. Microsurgical flaps may then be reserved for more important losses of soft tissues.
Humans↗
Determinants of acceptance of routine voluntary human immunodeficiency virus testing in an inner-city prenatal population.
Routine voluntary prenatal human immunodeficiency virus (HIV) counseling and testing offer the opportunity to encourage reduction of high-risk behaviors among uninfected women and to identify those women with asymptomatic HIV infection. To characterize the determinants of acceptance of routinely offered and encouraged HIV testing in inner-city parturients in Atlanta, we identified two groups of women, one that declined HIV testing and another that accepted testing. Each group was asked to complete a questionnaire designed to assess the effectiveness of pre-test counseling. During the 7-month study period, 4731 women registered for prenatal care and 4574 (97%) consented to HIV testing. Nearly all women stated that they were not pressured into having HIV testing performed. Women who accepted HIV testing were more likely to be young, black, and single (P less than .001) and less likely to have received education beyond high school (P less than .05). More accepters than decliners thought the HIV counseling session was valuable (97 versus 91%; P = .04); 55% of accepters agreed to antibody testing because of concern about the risk of transmitting HIV infection to their fetus or infant. More accepters than decliners indicated a willingness to have HIV testing in a future pregnancy (74 versus 33%; P less than .001). These data suggest that most inner-city parturients in our institution view routine voluntary HIV counseling as a valuable component of their prenatal care.
Adolescent↗
Automated immunoassay for prolactin with the Abbott IMx analyzer.
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Autoanalysis↗
Routine human immunodeficiency virus infection screening in unregistered and registered inner-city parturients.
Women who receive little or no prenatal care are at increased risk of adverse pregnancy outcome. Although many of these women are disadvantaged and presumably at increased risk for human immunodeficiency virus (HIV) infection, few data are available to describe risk behaviors and infection prevalence in this population. To better characterize HIV infection in unregistered inner-city parturients in Atlanta, we offered routine voluntary screening for HIV antibody and requested HIV risk-behavior profiles on all unregistered and registered parturients seen at Grady Memorial Hospital from July 1, 1987 to June 30, 1988. Of the 834 unregistered and 7356 registered parturients screened, significantly more unregistered parturients were seropositive on enzyme-linked immunosorbent assay and Western blot testing, 12 (1.4%) versus 26 (0.4%) (odds ratio 4.06; 95% confidence interval 1.93-8.43). Five unregistered and 15 registered parturients were seropositive by repeat enzyme-linked immunosorbent assay testing but were Western blot-negative. Significantly more unregistered parturients reported both a history of intravenous drug use, 4.4 versus 1.5% (odds ratio 3.09; 95% confidence interval 2.10-4.54), and crack cocaine use, 3 versus 0.8% (odds ratio 3.96; 95% confidence interval 2.42-6.44). Significantly more unregistered parturients acknowledged risk factors for HIV infection, 14.3 versus 9.9% (odds ratio 1.46; 95% confidence interval 1.19-1.80). Nearly all registered and 86% of unregistered parturients consented to HIV testing. Nearly all parturients completed HIV risk-behavior questionnaires. These data suggest that unregistered inner-city parturients in Atlanta are at greater risk of being HIV-infected and are more likely to report risk behaviors for infection.
Adolescent↗
Decreased very low density lipoprotein fluidity in familial hypercholesterolemia.
The fluidity of lipoproteins from normolipidemic subjects and from familial hypercholesterolemic patients was investigated by fluorescence polarization. The fluorescent probe DPH (1,6-diphenyl-1,3,5-hexatriene) was incorporated into the lipoprotein fractions, and assessment of the fluidity pattern of each particle was determined by fluorescence anisotropy measurements over a temperature range of 10 to 40 degrees C. The very low density lipoprotein (VLDL) of the hypercholesterolemic patients was found to be considerably more rigid than the respective VLDL of normolipidemic subjects. Analysis of the constituents of the various lipoproteins suggested that the large difference in the fluidity between hypercholesterolemic and normal VLDL patients might be due to increased VLDL cholesterol/triglyceride, cholesterol/protein and cholesterol/phospholipid ratios, which were 10, 2 and 1.4 fold higher, respectively, in the hypercholesterolemic VLDL patients. Decreased VLDL fluidity in familial hypercholesterolemic patients may be of importance in the pathogenesis of their accelerated atherosclerosis.
Adolescent↗
Simultaneous measurement of bone formation and resorption in vivo.
Bone resorption and formation in terms of milligram of calcium deposited into and released from whole humerus of 15-23 weeks old male rats were assessed, via linear least-squares regression analysis of change in calcium content and 3H-tetracycline kinetics of the bone. The rate of resorption was 0.376 mg calcium per day, while formation was 0.758 mg calcium per day. The data indicate that the computation results in a simultaneous and explicit measurement of bone resorption and formation at the organ level.
Animals↗
Variation of resorption rates in vivo of various bones in immature rats.
The 3H-tetracycline method of measuring bone resorption in vivo was applied to the comparison of various whole bones in rats of two different ages. The rat was chosen because it grows via modelling processes and contains little, if any, cortical remodelling except for a small amount of trabecular remodelling. It was found that resorption rates in vivo are high and similar in almost all of the 18 bones measured between birth and 2 weeks of age. However, in weanling rats studied at 4-6 weeks of age, resorption rates in the skull and in the long bones had decreased significantly while remaining high in the vertebrae, scapula, sternum and pelvis. Bones of neonatal rats were quite alike in their rates of bone resorption, but the bones of the weanlings manifested significant heterogeneity in their rates. It is known that anatomic heterogeneity of metabolic turnover of various bones characterizes the mature state in humans and dogs as well. The present data are unique in that they reflect absolute resorption rates in vivo uncomplicated by the extensive re-utilization of calcium inherent in other isotopic or non-isotopic protocols.
Animals↗
Decreasing rates of bone resorption in growing rats in vivo: comparison of different types of bones.
This study quantifies rates of bone resorption by measuring the kinetic loss of 3H-tetracycline in vivo from the five different types of whole bones in four ages of normal male rats: appendicular bone (femur), cephalic bone (calvarium), axial bones (sixth lumbar vertebrae and sternum), and pelvis. The skeletons of newborn (0-2 weeks), weanling (4-7 weeks), adolescence (10-14 weeks), and mature (15-23 weeks) of Sprague Dawley rats were multiply labeled with 3H-tetracycline. The radioactivity in whole calvaria, the 6th lumbar vertebra, sternum, pelvis and femur was quantified to calculate the time course of tetracycline loss. The isotopic half lives (t1/2) were different for each age group and each bone, but the rates of resorption were usually the highest in the newborn rats. In the youngest animals, the t1/2 for the femur, vertebrae, and sternum was 1.5 week, for the pelvis it was 2.0 week, and for the calvarium it was 2.5 week. In the oldest age group, t1/2 for the femur was 28 week, for the calvarium was 19 week, for the sternum and pelvis was 16.5 week, and for the vertebrae was 13 week. For cephalic bones and femur, the greatest decrement in the rate of resorption occurred in the first 7 weeks of life (-52% and -72%, respectively). The axial bones and pelvis maintained a uniformly high resorptive rate until 7 weeks of age, which waned sharply at adolescence (-70% to -78%). At maturity the resorptive rate of these bones was less than 16% of the rate in the newborn.(ABSTRACT TRUNCATED AT 250 WORDS)
Aging↗
Anesthetic complications in the horse.
The basis for management of all complications is early recognition, preparation, and a problem-solving approach. Some anesthetic complications, such as equipment malfunction and injuries from endotracheal intubation or misplaced drug injections, are common to all animals and can be prevented almost entirely by careful management. Other problems, such as pulmonary dysfunction and cardiovascular depression, seem to occur more often in healthy horses than in healthy members of other domestic species. Postoperative myopathy-neuropathy, sometimes a devastating complication, seems to be peculiar to the horse, and its incidence has been linked to hypotensive inhalant anesthesia. Careful positioning and padding, monitoring of anesthetic depth, and treating of cardiovascular depression may prevent most cases of postanesthetic myopathy. Idiosyncratic drug reactions, such as MH, are entirely unpredictable and can be rapidly fatal unless recognized early and treated vigorously and specifically.
Anesthesia↗
Antigenic requirements for stimulation and target cell recognition by immune and non-immune cytotoxic T lymphocytes.
The molecular requirements for recognition of antigen-modified cells by cytotoxic T lymphocyte precursors (CTLp) and their activated progeny, cytotoxic T lymphocytes (CTL), have been compared using haptenated stimulator and target cells. The antigen density requirements of T cell recognition by fluorescein-specific CTLp and CTL derived both from naive mice and from animals previously primed in vivo were determined. The cell surface hapten concentration required to stimulate CTLp cannot be distinguished from that required on target cells for lysis by their mature daughter CTL 5-7 days later. However, if the CTL (and their precursor CTLp) are derived from mice primed in vivo with hapten-conjugated cells, they require lower cell surface hapten densities for recognition than do the analogous T cell populations from naive animals. Thus, the maturation of CTLp into CTL during 5-7 days in vitro does not result in any functionally relevant change in the nature or density of antigen receptors on the surface of the T cell. This is in contrast to the apparent selection which occurs over longer time periods in vivo following priming.
Animals↗
Molecular structure of frizzled, a Drosophila tissue polarity gene.
The function of the frizzled (fz) locus is required to coordinate the cytoskeletons of pupal epidermal cells so that a parallel array of cuticular hairs and bristles is produced. We report here the molecular cloning and characterization of the fz locus. The locus is very large. Mutations that inactivate the gene are spread over 100 kb of genomic DNA. The major mRNA product of the gene is a 4-kb RNA that is encoded by 5 exons spread over more than 90 kb of genomic DNA. Conceptual translation of this mRNA indicates that it encodes an integral membrane protein that is likely to contain both extracellular and cytoplasmic domains.
Amino Acid Sequence↗
Visualization of multimodality cardiac imagery.
A large number of clinically important and medically difficult decisions in diagnostic radiology involve interpreting the information derived from multiple imaging modalities. This is especially true in the assessment of heart disease, wherein at least two types of image information are generally required prior to deciding on the course of action: structural information describing coronary vessel anatomy and functional information related to heart muscle physiology. This paper will present and discuss the methods and results associated with a research program aimed at quantifying and visualizing the unified anatomic and physiologic information obtained from these complementary imaging modalities. The discussions will emphasize the reconstruction, processing, and visualization of three-dimensional cardiovascular structure, including the procedures and results obtained from phantom and patient studies.
Computer Graphics↗
Cyclosporin A and tissue antigen matching in bone transplantation. Fibular allografts studied in the dog.
We studied the mechanical, metabolic, and histologic properties of short-term nonvascularized cortical bone grafts in a canine fibular graft model. Sham operated nonvascularized autotransplanted and allotransplanted bones were compared. The allografts were performed between dog leukocyte antigen (DLA) class I and II matched; DLA class I and II mismatched; and cyclosporin A (CsA) treated, DLA class I and II mismatched animals. Cyclosporin was given for 1 month, and all the animals were followed for 3 months after surgery. Mechanical properties were investigated using standard torsional tests, metabolic kinetics were assessed using isotopic prelabeling techniques, and histomorphometric analysis of cross-sectional area properties and sequential fluorochrome labels were performed. Autografts were mechanically stronger and stiffer than all the types of allograft. CsA-treated, DLA-mismatched allografts performed better than matched allografts. These in turn were stronger than non-CsA-treated, mismatched allografts, which underwent nearly complete resorption. These relationships were preserved in the metabolic and histologic analyses. In this short-term animal study, although DLA matching resulted in a slight improvement in graft outcome, mismatched grafts in dogs receiving a short course of cyclosporin A fared even better.
Animals↗