Advantages of the CBA mouse in leukemogenesis research.

The objectives of this review are to: (a) demonstrate that the male CBA/Ca mouse has several characteristics that make it an excellent animal for the study of leukemogenesis, (b) show that several of the genetic abnormalities observed in the male CBA/Ca mouse during the development of radiation induced acute myeloid leukemia (AML) are syntenic with those frequently detected in patients with myeloid disorders such as myelodysplastic syndrome and AML, (c) illustrate that leukemia-related chromosomal lesions are the indicators for high risk individuals.

Cellular signal adaptation with damage control at low doses versus the predominance of DNA damage at high doses.

Ionizing radiation is known to potentially interfere with cellular functions at all levels of cell organization and induces DNA lesions apparently with an incidence linearly related to D, also at low doses. On the other hand, low doses have also been observed to initiate a slowly appearing temporary protection against causation and accumulation of DNA lesions, involving the radical detoxification system, DNA repair and removal of DNA damage. This protection apparently does not operate at high doses; it has been described to be nonlinear, increasing initially with D, beginning to decrease when D exceeds approximately 0.

Application of random amplified polymorphic DNA PCR for genomic analysis of HIV-1-infected individuals.

Random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) is a DNA fingerprinting technique used to detect genomic polymorphisms. We employed sixteen different RAPD-PCR 10-mer primers to amplify DNA from the peripheral blood mononuclear cells (PBMC) of 80 HIV-1-infected individuals. These individuals were previously identified as either heterozygotes (+ /delta32) and homozygotes (+/+) for the CCR5 locus by PCR with gene specific primers.

Parental report of occurrences and consequences of traumatic brain injury among delinquent and non-delinquent youth.

Completed questionnaires from parents of youths attending a public middle school or high school and parents of youths admitted to an institution for juvenile delinquents provided information about incidents of traumatic brain injury (TBI) in their children. Results revealed that approximately 40% of the non-delinquent youth and 50% of the delinquent youth had sustained one or more TBIs during their childhood or youth. The majority of injuries appeared to be mild and had no permanent consequences.

Growth inhibition of subcutaneously transplanted hepatomas without cachexia by alteration of the dietary arginine-methionine balance.

Previous studies have shown that alteration of the dietary arginine-methionine balance by use of synthetic L-amino acids inhibits tumor growth of a subcutaneously transplanted Morris hepatoma at the expense of maintaining body weight. However, L-methionine is susceptible to degradation and, therefore, may contribute to a deficiency state. The present studies were performed to determine whether growth of subcutaneous hepatoma transplants is inhibited, and body growth maintained, when rats are fed diets containing L-methionine in replacement of N-acetyl-L-methionine (NALM) for 28 days.

Epidemiology of HIV-1 infection in rural Georgia: demographic trends and analysis at the Medical College of Georgia.

We have conducted a retrospective study of 100 HIV-infected patients enrolled in an AZT monotherapy clinical study at the Medical College of Georgia (MCG) in Augusta, Georgia. When compared to the national trends, our results confirm previous studies that describe an overall increase in the burden of HIV infections among blacks, and, in particular, black women in the rural Southeast. In our cohort, infections due to homosexual contact accounted for approximately 40% of all cases while heterosexual contact and intravenous drug use (IDU) comprised 33% and 13%, respectively.

Effects of the human immunodeficiency virus type 1 Rev protein on reporter gene and host T-cell gene expression.

The HIV-1 encoded regulatory Rev protein acts to selectively increase the cytoplasmic concentration of incompletely spliced viral mRNAs through interaction with the Rev responsive element (RRE). In addition, the Rev activation domain, believed to be a nuclear export sequence, has been shown to modulate the export of non-RRE containing RNAs (e.g.

Skeletal muscle fibre type and capillary density in college-aged blacks and whites.

The purpose of this study was to compare muscle fibre type proportions and capillary density in untrained, college-aged blacks (n = 14) and whites (n = 14). Both groups were similar in terms of peak oxygen uptake (VO2peak), measured during cycle ergometry (blacks: 42.6 +/- 4, whites: 44.

Historical events associated with fallout from Bravo Shot--Operation Castle and 25 Y of medical findings.

The events prior to Bravo Shot-Operation Castle that led to a decision not to evacuate the Marshallese prior to testing the thermonuclear bombs are presented as are the actions taken after the fallout incident in evacuating the exposed Marshallese and the military personnel. The initial medical effects (findings during first 6 wk after exposure) are briefly described and are followed by description of long term effects, namely, induction of one case of fatal acute myeloid leukemia and a large number of thyroid tumors (benign and malignant) in addition to hypothyroidism in adults and children and two cases of cretinism. The hypothyroidism and cretinism responded well to administration of oral thyroxine.

Identification of a second endogenous Porphyromonas gingivalis insertion element.

In this study a second endogenous Porphyromonas gingivalis insertion element (IS element) that is capable of transposition within P. gingivalis was identified. Nucleotide sequence analysis of the Tn4351 insertion site in a P.

The difficulties of compiling a glossary of diseases associated with sexual intercourse in Chiawa, rural Zambia.

It is increasingly appreciated that health interventions need to be sensitive to cultural perceptions of diseases and local disease terminology. This paper examines linguistic and conceptual problems encountered when researchers in rural Zambia try to develop a glossary which correlates biomedical terms for sexually transmitted diseases (STDs) with local terms for diseases associated with sexual intercourse. Problems arise because it is difficult to establish definite connections between local names and actual biomedical STDs.

Evidence for an uncommon microsatellite instability on mouse chromosomes 2 and 4 and its possible role in radiation leukemogenesis.

Although microsatellite instability (MSI), usually detected by DNA length polymorphisms, has been implicated in the induction of solid tumors in both humans and animals, its role in leukemogenesis is unclear. The goal of this study was to investigate whether there is an association between MSI and radiation leukemogenesis in CBA/Ca mice. Microsatellite lengths at 55 loci, mapped to eight different mouse chromosomes, were examined in two groups of DNA samples: 1) 10 normal DNA samples collected from the bone marrow cells of control male CBA/Ca mice, and 2) 17 DNA samples isolated from the spleens of mice that developed myeloid leukemia (ML) after exposure to neutrons, or X rays, or gamma rays.

'Between a rock and a hard place': applied anthropology and AIDS research on a commercial farm in Zambia.

Fieldwork on a commercial farm in southern Zambia, which was aimed at designing an HIV prevention program for farm workers, gradually exposed the nature of sexual liaisons between young girls, coming to work on the farm from the surrounding villages, and older migrant men workers. Before completing fieldwork, the anthropologist voiced her concern about the implications of these liaisons for the spread of STDs and HIV with the local rural community, farm management and farm workers. The immediate outcome of her intercessions was the decision by management to sack under-age workers.

Men, women and the trouble with condoms: problems associated with condom use by migrant workers in rural Zambia.

Understanding cultural attitudes to condoms is of the utmost importance in promoting their use as a means of protection against HIV transmission. This article examines condom use in relation to what people see as the purpose of sex, what good sex entails and how this relates to ideas of being a proper woman or man. It seems that the underlying and pervasive ideal is that sex is essentially a procreative act, since an emphasis on male potency and male and female fertility often overrides anxieties about contracting HIV and other sexually transmitted diseases.

Race and physical activity: cardiovascular and renal response to sodium loading.

Race and level of physical activity may be important factors affecting cardiovascular responsiveness to acute sodium intake. We examined the effects of a 4-day sodium loading procedure on heart rate (HR), systolic (SBP) and diastolic (DBP) blood pressure, 24-hour electrolyte excretion, and extracellular fluid volume (ECF) in African-American (n = 16) and Caucasian (n = 16) adult males. All subjects were normotensive with either moderately high (> or = 3 day/wk; > or = 20 min/day) or low (< or = 3 day/wk; < or = 20 min/day) physical activity levels.

Racial differences in minimum lower leg vascular resistance in normotensive young adults with positive and negative parental histories of hypertension.

Objective: To determine whether peripheral hemodynamic differences exist in young adult normotensive African Americans and white Americans with a positive and negative parental history of hypertension.

Methods: The participants were healthy men of whom 13 were African Americans and nine white Americans with a positive parental history and 19 were African Americans and 13 white Americans with a negative parental history. Lower leg blood flows were obtained at rest and during reactive hyperemia.

Lower leg high-intensity resistance training and peripheral hemodynamic adaptations.

High-intensity resistance (HIR) training has been associated with muscle hypertrophy and decreased microvascular density that might produce a blood flow limitation. The effect of HIR training on lower leg maximal blood flow and minimum vascular resistance (Rmin) during reactive hyperemia were investigated in 7 healthy males. The gastrocnemius-soleus muscles of one leg were trained using maximal isokinetic concentric contractions for 4 weeks; the nontrained leg was the control.

Current misinterpretations of the linear no-threshold hypothesis.

Contrary to the "linear no-threshold hypothesis," which implies that "any amount, however small" of radiation energy is a serious cancer threat, it is shown here that only relatively quite large amounts of such energy can pose such a threat to a person or population. Key to doing this is to make a sharp distinction between the actual amount of the radiation agent imparted energy, epsilon, which must be expressed in units of joules, and the average concentration or density of energy, epsilon/m (i.e.

The use of cell-oriented factors and the hit size effectiveness function in radiation protection.

It has long been argued that ionizing radiation can be considered to interact with matter in discrete, randomly occurring energy transferring events ("hits") and that the resulting microscopically nonuniform pattern of energy deposition strongly influences the biological effect of a given exposure. Microdosimetric measurements combined with cellular biological response data in the form of a "hit size effectiveness function" (HSEF) suggest a possible cell-oriented alternative method of correlating exposure with effect at low levels of any radiation or mixture of radiations. The instrumentation required, the validity of the approach, and its practical usefulness in radiation protection are examined, and its application to space radiation exposure is proposed as a test case.

Relative biological effectiveness of ionizing radiations determined in tissue (RBE) fails in assessing comparative relative effectiveness in the tissue cells.

The value of the RBE of a test radiation is conventionally determined against a known standard radiation for a chosen response of a selected biological tissue and is expressed as the ratio of tissue absorbed doses at equal effect, or as ratio of magnitudes of the effect at equal absorbed dose. If such an effect is observable as a consequence of responses of individual elements of this tissue, namely the cells, such as induction of cancer that arises from a single cell, the relative biological effectiveness should be expressed as the ratio of the incidences of the effects at equal mean absorbed dose to the cells rather than at equal absorbed dose to tissue. This cell based relative biological effectiveness is here termed the relative local efficiency.