Diabetes and hypertension: a review.

The basic mechanisms that initiate and sustain hypertension in type 2 diabetics are poorly understood. Contributing factors discussed in this review include obesity, insulin resistance, hyperinsulinemia, genetic factors, and abnormalities of cellular cation homeostasis. Also discussed are the features of hypertension in type 2 diabetic individuals that are reminiscent of the hemodynamic abnormalities characterizing hypertension in the elderly, including increased vascular reactivity and increased atherosclerotic vascular disease. This article reviews mechanisms by which hyperinsulinemia, insulin resistance, or both may lead to hypertension.     

Penetration of hematoporphyrin derivative into rat brain and intracerebral 9L glioma tissue

Summary Brain and glioma tissue levels of tritiated hematoporphyrin derivative (³H-HPD) were measured in normal and 9L intracerebral glioma-bearing rats at 24 hours following administration of³H-HPD 2–20 mg/kg and at 24–120 hours after³H-HPD 10 mg/kg. Levels of³H-HPD in blood, liver, spleen and muscle were also measured.Tissue levels of³H-HPD increased progressively as the dose was increased. In animals given 10 mg/kg, gradual decreases in tissue levels occurred between 24 and 72 hours but thereafter remained stable. The³H-HPD level in gliomas was consistently 2–3 × greater than in brain tissue, despite changes in dosage and time interval. High levels of activity were measured in normal brain tissue at all dosage levels, and subsequent clearance of the³H-HPD from brain, glioma, and other tissues was slow; at 120 hours after administration of 10 mg/kg, approximately 50% of the 24 hour level was still present.These results indicate that although a dose- and time-independent preferential uptake of hematoporphyrin derivative occurs in intracerebral gliomas, persistent high levels may be present in the surrounding brain. The disadvantages of using hematoporphyrin derivative rather than its individual components in studies of HPD uptake and photosensitization in the brain are discussed.     

Effect of CO2 and blood media on laser probe temperature

Blood may limit laser ablation of arterial plaque by decreasing thermal energy transfer from metal-capped probes to arterial occlusions. Since a gas is a good insulator of heat, CO2 may be a better medium for laser recanalization. To study this possibility, a metal-capped fiber was positioned in a segment of blood-filled polyethylene tubing and activated with an argon laser. Probe temperatures were measured in blood and as the blood was displaced by flowing CO2 gas. Probe temperatures were higher at all powers studied in CO2 gas than in blood. Maximum probe temperatures averaged 518 +/- 24 degrees C after CO2 infusion versus 320 +/- 7 degrees C in blood, (P less than 0.0001). Blood aggregate formation was noted on the probe surface in blood but not in CO2 medium. Thus CO2 gas may be a preferable medium for laser recanalization, since higher probe temperatures are achieved, and the probe surface remains free of insulating blood coagulate.     

Scope and strategies of Genetic Epidemiology: Analysis of articles published in Genetic Epidemiology, 1984–1991

Genetic epidemiology is a relatively new discipline that seeks to unravel the role of genetic factors and their interactions with environmental factors in the etiology of diseases, using population and family study approaches. To characterize the overall direction and emphasis of research strategies used in this field, we reviewed original research articles published in the journal Genetic Epidemiology since its inception in 1984 until the end of 1991. Of 259 published original articles, 92 (35%) focused primarily on methodologic/statistical developments, most commonly in the area of linkage analysis/gene mapping, and 167 (65%) articles were applied or data-derived. Only 42 articles (16%) were population studies, and 217 (84%) were family studies. Most family studies dealt with genetic analysis of pedigree data using segregation and linkage analyses. Of the 137 applied family studies, 73 (53%) were drawn from well-defined populations, and only 40 (29%) considered specific environmental factors in their analyses. These findings clearly indicate a rapid growth in the methodologic and statistical aspects of genetic epidemiology, and in the emphasis on family-based studies and genetic analysis methods. Further developments in genetic epidemiology will require greater integration of epidemiologic approaches of study design and analyses into population and family studies of disease etiology. © 1993 Wiley-Liss, Inc.     

Ovarian tumor and Peutz-Jeghers syndrome. A case report

A case of Peutz-Jeghers syndrome associated with ovarian mucinous cystadenoma and ovarian sex cord tumor with annular tubules is presented. The sec cord tumor with annular tubules was described in 1970 by Scully, who recognized its striking association with the Peutz-Jeghers syndrome. This tumor is an almost constant finding in patients' ovaries with this disorder. Three cases of ovarian mucinous cystadenoma and sex cord tumor with annular tubules associated with Peutz-Jeghers syndrome were found in the literature. Our observation confirms that gynecologic abnormalities are an important manifestation of the syndrome and require careful surveillance.     

Mechanism of electrical enhancement of efficacy of antibiotics in killing biofilm bacteria.

The bioelectric effect, in which electric fields are used to enhance the efficacy of biocides and antibiotics in killing biofilm bacteria, has been shown to reduce the very high concentrations of these antibacterial agents needed to kill biofilm bacteria to levels very close to those needed to kill planktonic (floating) bacteria of the same species. In this report, we show that biofilm bacteria are readily killed by an antibiotic on all areas of the active electrodes and on the surfaces of conductive elements that lie within the electric field but do not themselves function as electrodes. Considerations of electrode geometry indicate that very low (< 100 microA/cm2) current densities may be effective in this electrical enhancement of antibiotic efficacy against biofilm bacteria, and flow experiments indicate that this bioelectric effect does not appear to depend entirely on the possible local electrochemical generation of antibacterial molecules or ions. These data are expected to facilitate the use of the bioelectric effect in the prevention and treatment of device-related bacterial infections that are caused by bacteria that grow in biofilms and thereby frustrate antibiotic chemotherapy.