Growth rate rather than gender determines the size of the adaptive response of the growing skeleton to mechanical strain.

To determine whether male and female skeletons are equally responsive to mechanical load, the left ulnae in a group of juvenile male (n = 7), and age-matched female (n = 9) rats received a short daily period of controlled dynamic loading in vivo (1200 cycles at 2 Hz each day for 10 days) in addition to their normal exercise. Axial loads for each group were adjusted to engender a peak dynamic strain of -4000 microstrain at the medial face of the ulna midshaft, applied and released at a rate of +/-30,000 microstrain/sec. Fluorescent labels were administered at the start and finish of the loading period.

Linkage analysis of alpha 1-antitrypsin deficiency: lessons for complex diseases.

Objectives: Severe alpha 1-antitrypsin (A1AT) deficiency is the one proven genetic risk factor for chronic obstructive pulmonary disease (COPD). Familial aggregation has been demonstrated for COPD among individuals who do not have A1AT deficiency, but linkage analysis of COPD has not been reported. To investigate the optimal phenotype definitions and analytical methods for the linkage analysis of COPD, we examined a set of 28 A1AT- deficient families containing 155 individuals.

Cardiovascular risk factors in normotensive and hypertensive Egyptians.

Objectives: To define the prevalence of cardiovascular risk factors and their relation to the level of blood pressure, in Egyptians.

Methods: Data were collected during the Egyptian National Hypertension project, a national hypertension survey in Egypt. During phase I of the survey, hypertensive (HT) patients were identified.

Age-related deficits in cognitive functioning are not mediated by time of day.

Few studies have examined whether cognitive performance of adults is influenced by the time of day in which they are tested. It has been suggested (May, Hasher, & Zacks, 1993) that some of the reported age differences in performance may be attenuated when older adults are tested during their optimal time, and younger adults are tested during their nonoptimal time. A total of 100 adults (20 to 78 years of age) participated in this study to investigate whether time of day and/or age are significant predictors of cognitive performance.

Surveillance of HIV-1 genetic subtypesand diversity in the US blood supply.

Background: Recent reports of variant (non-subtype B) HIV infections in US populations have raised concerns about the sensitivity of subtype B virus-based donor screening and diagnostic assays. This study was designed to determine the prevalence and genetic diversity of HIV subtypes in US blood donors over the last two decades.

Study Design And Methods: Three groups were studied: hemophiliacs infected by clotting factor concentrates in the early 1980s (n = 49), blood donors retrospectively identified as being seropositive in 1985 (n = 97), and blood donors identified as seropositive between 1993 and 1996 (n = 405).

Hemispheric specialization for reading.

Behavioral laterality tasks with linguistic stimuli were used to assess the differential processing efficiencies of the cerebral hemispheres in right- and left-handed adults. Findings from a lateralized lexical decision task with concrete nouns supported Zaidel's (1983) "direct access" model of hemispheric functioning. A dual task consisting of oral and silent reading indicated that the right hand was significantly more disrupted than the left during unimanual finger tapping; however, some bilateral interference was observed.

Relationship between skin color and blood pressure in egyptian adults: results from the national hypertension project.

In many, but not all societies, dark skin color is associated with high blood pressure. Whether the association between skin color and blood pressure is independent of known determinants of blood pressure remains controversial. We examined the association between skin color and blood pressure in 835 Egyptian adults (370 men and 465 women) participating in the National Hypertension Project, a national survey of hypertension prevalence and blood pressure-related complications conducted in Egypt during 1991-1993.

Osteoporosis and bone functional adaptation: mechanobiological regulation of bone architecture in growing and adult bone, a review.

During life, bone is continually optimized for its load-bearing role by a process of functionally adaptive (re)modelling. This process, which is more active in growing bone, is dominated by high-magnitude, high-rate strains, presented in an unusual distribution. Adaptation occurs at an organ level, involving changes in whole bone architecture and bone mass.

Operative versus conservative management of adhesional intestinal obstruction.

AIMS: This prospective controlled trial was undertaken to resolve the controversy over whether intestinal obstruction due to postoperative adhesions should be managed by immediate operation or by conservative care. METHODS: A randomized prospective controlled study was undertaken of all private and public sector patients admitted under the care of one surgeon with intestinal obstruction due to postoperative adhesions over a 15-year period. The patients were randomly allocated either to immediate operation or conservative care with nasogastric aspiration and intravenous fluids.

Hemispheric processing deficits in patients with paranoid schizophrenia.

The purpose of the present study was to investigate hemispheric deficits in individuals with paranoid schizophrenia on four kinds of tasks: dichoptic viewing tasks involving verbal and nonverbal visual stimuli, and dichotic listening tasks involving verbal and nonverbal auditory stimuli. As dependent measures, both accuracy and speed of (correct) responding were measured. The sample recruited for this study consisted of 18 patients with paranoid schizophrenia, 15 outpatients with anxiety disorders, and 20 controls with no history of psychiatric disorders.

Developmental trends in right hemispheric participation in reading.

Behavioral laterality tasks assessed the differential processing efficiencies of the cerebral hemispheres in younger and older reading-age children. Lateralized lexical decision task findings supported a "direct access" model of hemispheric processing for the younger children whereas the older children demonstrated a "callosal relay" pattern. A dual-task with oral and silent reading indicated that the right hand was significantly more disrupted than the left during unimanual finger tapping.

An experimental, observational investigation of children's responses to peer provocation: developmental and gender differences in middle childhood.

The primary goal of this research was to use an experimental, observational method to study the development of anger expression during middle childhood. Eight-, 10-, and 12-year-old girls and boys (N = 382) were observed during a laboratory play session that was provoking in two ways: Participants lost a computer game they were playing for a desirable prize, and their play partner was a same-age, same-gender confederate actor who taunted them. Children's responses to the provoking play sessions--facial expressions, verbalizations, and gestures--were reliably coded.

Mechanical strain stimulates nitric oxide production by rapid activation of endothelial nitric oxide synthase in osteocytes.

Previous studies have indicated that physiological levels of dynamic mechanical strain produce rapid increases in nitric oxide (NO) release from rat ulna explants and primary cultures of osteoblast-like cells and embryonic chick osteocytes derived from long bones. To establish the mechanism by which loading-induced NO production may be regulated, we have examined: nitric oxide synthase (NOS) isoform mRNA and protein expression, the effect of mechanical loading in vivo on NOS mRNA expression, and the effect of mechanical strain on NO production by bone cells in culture. Using Northern blot analyses, in situ hybridization, and immunocytochemistry we have established that the predominant NOS isoform expressed in rat long bone periosteal osteoblasts and in a distinct population of cortical bone osteocytes is the endothelial form of NOS (eNOS), with little or no expression of the inducible NOS or neuronal NOS isoforms.

Bone's early responses to mechanical loading differ in distinct genetic strains of chick: selection for enhanced growth reduces skeletal adaptability.

Bone's functional competence is established and maintained, at least partly, by mechanisms involving appropriate adaptation to mechanical loading. These appear to fail in chickens selectively bred either for maximum egg (Egg-type) or meat (Meat-type) production, which show high rates of fracture and skeletal abnormality, respectively. By measuring several early strain-induced responses in cultured embryonic tibiotarsi from commercially bred (Egg-type and Meat-type) and wild-type (Wild-type) chicks, we have investigated the possibility that these skeletal failures are the product of a compromised ability to respond appropriately to loading-induced mechanical strain.

Heme oxygenase isozymes in bone: induction of HO-1 mRNA following physiological levels of mechanical loading in vivo.

Heme oxygenases (HO) are responsible for the production of carbon monoxide, which has been suggested to act similarly to nitric oxide as a signaling molecule. Inducible HO-1 and constitutive HO-2 were located in sections of weight-bearing ulnae of the rat by immunocytochemistry. Intense HO-1 localization was restricted to peri- and endosteal sites, whereas HO-2 staining occurred in osteoblasts and osteocytes throughout the cortex.

A 32-bp deletion within the CCR5 locus protects against transmission of parenterally acquired human immunodeficiency virus but does not affect progression to AIDS-defining illness.

The beta-chemokine receptor CCR5 is required as a coreceptor by non-syncytium-inducing (NSI) strains of human immunodeficiency virus type 1 (HIV-1). NSI viruses predominate early during an infection and are thought to be important for the transmission of HIV-1. The importance of CCR5 during parenteral transmission of HIV-1 was investigated.

Strain rate as a controlling influence on adaptive modeling in response to dynamic loading of the ulna in growing male rats.

To test the hypothesis that the rate of change of strain to which a bone is subjected is an important determinant to the subsequent functionally adaptive modeling response, the ulnae of growing male rats were subjected to dynamic axial loading in vivo for a short period each day over 2 weeks. Due to the longitudinal curvature of the ulna, such axial loading leads to both compression and bending. The left ulna in three groups of rats was loaded cyclically between 1 and 20 N in a trapezoidal pattern to produce dynamic, longitudinal compressive strains of -0.

Role of viral load in heterosexual transmission of human immunodeficiency virus type 1 by blood transfusion recipients. Transfusion Safety Study Group.

Eighteen transfusion recipients infected with human immunodeficiency virus type 1 (HIV-1) were followed prospectively with their 19 long-term sexual partners from 1986 to 1993 in California, Florida, and New York. Follow-up included clinical, behavioral, immunologic, serologic, and virologic evaluations. Two partners were already infected when seen 18 and 34 months after sexual contact began following the infectious transfusion.

Comparative rates of disease progression among persons infected with the same or different HIV-1 strains. The Transfusion Safety Study Group.

Rates of HIV-1 progression vary widely. To investigate the relative effects of viral and host characteristics on course, we compared persons infected by the same and different subtype B strains. Forty-three infection chain clusters were identified, each defined by an infected blood donor, that donor's recipients, and the recipients' sexual partners, representing second and third generations of infection.