The effect of hyperthermia on microcirculatory and metabolic parameters in s.c. DS-sarcomas of different sizes on the hind foot dorsum of SD-rats was investigated. Hyperthermia was carried out using a novel water-filtered, infrared-A radiation technique. Heating was performed at a rate of 0.5 degrees C/min until 44 degrees C was achieved in the tumour centre, which was maintained for 60 min. Using a multichannel laser Doppler flowmeter, red blood cell flux could be assessed continuously and at several sites within the tumour tissue simultaneously. Substantial inter-site variations in laser Doppler flux (LDF) were observed during hyperthermia which were independent of tumour size, site of measurement, and temperature at the site of measurement, indicating that single site measurements of tumour LDF are poor predictors of the mean response of a tumour to hyperthermia. When mean LDF was considered, decreases in red blood cell fluxes occurred that were more pronounced the greater the tumour volume. In no case was vascular stasis observed. Hyperthermia did not affect tumour oxygenation substantially. Microregional and global assessment of lactate and ATP concentrations demonstrated increased lactate and decreased ATP levels following hyperthermia. Tumour glucose levels were increased following hyperthermia, possibly due to an enlarged distribution space resulting from development of interstitial oedema. Changes in lactate and ATP levels and the lack of changes in tumour oxygenation suggest a modification of energy metabolism following hyperthermia in the form of increased ATP hydrolysis, intensified glycolysis and impaired oxidative phosphorylation.

Adenosine Triphosphate↗

PubMedDate not supplied

Oral antibiotic prophylaxis of bacterial endocarditis--why amoxicillin?

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Amoxicillin↗

PubMedDate not supplied

Pregnancy outcomes of U.S.-born Puerto Ricans: the role of maternal nativity status.

This study examines maternal sociodemographic characteristics, prenatal care use, and birth outcomes of U.S. resident Puerto Ricans by maternal nativity status in order to ascertain if Puerto Rican-born mothers exhibit better birth outcomes than U.S.-born Puerto Rican mothers, after controlling for maternal risk characteristics. All single live births to U.S. resident mothers indicating a Puerto Rican heritage or ethnicity on the infant's Certificate of Live Birth were selected for analysis from the 1983-1986 National Center for Health Statistics' Public Use U.S. Linked Live Birth and Infant Death File. Infants of Puerto Rican-born mothers had a significantly lower risk of low birthweight and small for gestational age infants than infants of U.S.-born Puerto Rican mothers, after controlling for available maternal risk factors. Nevertheless, infants of Puerto Rican-born mothers had a significantly higher risk of neonatal mortality, although they exhibited a significantly lower risk of postneonatal mortality. No significant maternal nativity status differences in very preterm, preterm, very low birthweight, and infant mortality were identified after controlling for the same maternal sociodemographic and prenatal care use variables. Infants of Puerto Rican-born mothers demonstrated higher birthweight-specific neonatal mortality rates but lower birthweight-specific postneonatal mortality rates for nearly every birthweight category. These findings emphasize the need for further investigation of the factors that may influence maternal nativity variations in intrauterine growth retardation, access to tertiary health care services, and postneonatal mortality.

Adolescent↗