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We have used fluorescence and circular dichroism spectroscopy to investigate the effect of phospholipid on the structure and molecular stability of human apolipoprotein A-IV (apo-A-IV). Binding of apo-A-IV to egg phosphatidylcholine vesicles was rapid and did not cause release of encapsulated 6-carboxyfluorescein. Fluorometric titration established that apo-A-IV bound to the vesicles with an association constant of 1.36 x 10(6) liters/mol and a binding maximum of 2 molecules per vesicle. Binding of apo-A-IV to the vesicle surface caused a progressive increase in alpha helicity from 43% at baseline to 83% at saturation; denaturation studies showed that the free energy of stabilization of binding was 6.31 kcal/mol. Fluorescence quenching studies revealed that binding of apo-A-IV to the vesicles was associated with a dramatic decrease in the fractional exposure of tyrosine to iodide, and a decrease in the efficiency of intramolecular tyrosine-tryptophan energy transfer. These findings suggest that the binding of apo-A-IV to the vesicle surface may involve a relaxation of the globular protein conformation in which the tyrosine containing alpha-helical domains surrounding the tryptophan "unfold" and reorient their hydrophobic faces toward the phospholipid monolayer, with a consequent induction of additional alpha-helical structure. However, our data also suggest that apo-A-IV does not penetrate deeply into the region of the phospholipid fatty acyl chains, but rather sits higher in the monolayer, intercalated between the charged phospholipid head groups. This characteristic may determine the labile interaction of apo-A-IV with high density lipoproteins.

To determine whether venting the left ventricle during coronary reperfusion limits myocardial infarct size, we studied paced (200 beats/min) Langendorff rabbit hearts, perfused with blood from a support rabbit. A left coronary artery was occluded for 60 minutes, followed by 2 hours of reperfusion. Four experimental conditions, as follows, were used: In group 1 (control), the hearts contracted isovolumetrically on a fluid-filled balloon in the left ventricle during both occlusion and reperfusion. In group 2, the balloon was present only during occlusion, and the heart was vented during reperfusion. Hearts in group 3 were vented during occlusion and developed pressure during reperfusion. In group 4, the left ventricle was vented during occlusion and reperfusion. Perfusion pressure (91.2 +/- 0.9 mm Hg) and coronary flow (0.88 +/- 0.03 ml/min/g) were not different between groups. Left ventricular pressures (mean of all groups) were 87.3 +/- 1.5 mm Hg systolic and 6.5 +/- 0.6 mm Hg diastolic. Infarcted myocardium was assessed by triphenyl tetrazolium staining and expressed as a percentage of the area at risk, as measured by fluorescent particles. Venting during both ischemia and reperfusion (n = 10) did result in significantly smaller infarcts than in the unvented controls (n = 10), that is, 13 +/- 5% vs. 41 +/- 6%, respectively. Venting only during reperfusion (n = 10) or occlusion (n = 11) did not significantly limit infarct size (57 +/- 6% and 32 +/- 5%, respectively), as compared with controls. Thus, the clinically feasible intervention of left ventricular venting during reperfusion was not cardioprotective.

Viral pulmonary infections are a major cause of morbidity and mortality in solid organ transplant recipients. The herpes viruses-cytomegalovirus, herpes simplex virus, varicella zoster virus, and Epstein-Barr virus--cause most of the viral infections in this population. Respiratory syncytial virus, adenovirus, and human immunodeficiency virus also cause pneumonitis in the transplant recipient. Differences in the clinical and laboratory presentation of pneumonitis due to the various viral agents can provide clues to the etiology. However, definitive diagnosis requires laboratory identification of the virus or appropriate serologic changes. With cytomegalovirus, herpes simplex virus, Epstein-Barr virus, and adenovirus, one must take care to distinguish between asymptomatic shedding of the virus and disease produced by the virus. Advances in diagnostic techniques such as rapid antigen detection, nucleic acid hybridization, and gene amplification may allow an earlier diagnosis of viral pneumonia. Advances in risk reduction with appropriate pairing of donors and recipients, improved immunosuppressive regimens, vaccination, and prophylactic administration of antiviral agents may reduce the incidence of viral infection. Finally, advances in anti-viral therapy have made possible the successful treatment of pneumonia due to some of the viral agents.

We investigated the association between self-reported constipation and several demographic and dietary variables in 15,014 men and women 12-74 years of age examined between 1971-75 during the first Health and Nutrition Examination Survey. Overall, 12.8 percent reported constipation. Self-reported constipation correlated poorly with stool frequency. Nine percent of those with daily stools and 30.6 percent of those with four to six stools/week, reported constipation. Constipation was more frequent in Blacks (17.3 percent), women (18.2 percent), and those over age 60 (23.3 percent); after adjusting for age, sex, and race it was more prevalent in those with daily inactivity, little leisure exercise, low income, and poor education. Constipated subjects reported lower consumption of cheese, dry beans and peas, milk, meat and poultry, beverages (sweetened, carbonated and noncarbonated), and fruits and vegetables. They reported higher consumption of coffee or tea. They consumed fewer total calories even after controlling for body mass and exercise.

Triticale (× Triticosecale Wittmack) is a man-made cereal grain developed through the hybridization of wheat (Triticum aestivum or Triticum durum) and rye (Secale cereale) The first fertile hybrid was developed by Rimpau in 1891 but interest in developing triticale as a potential crop species did not occur until after the discovery of the chromosome doubling property of colchicine in the 1930’s (Bushuk and Larter 1980). It was hoped that triticale would combine the quality and productivity of wheat with the vigor and hardiness of rye.

Real-time metabolic monitoring of varied vascular beds provides the raw data necessary to conduct ultraprecise burn shock resuscitation based on second-by-second assessment of regional tissue perfusion. It also illustrates shortcomings of current clinical practices. Arterial base deficit was continuously monitored during 11 clinical resuscitations of patients suffering burn shock using a Paratrend monitor. Separately, in a 30% TBSA rat burn model (N = 70), three Paratrend monitors simultaneously recorded arterial blood gas and tissue pCO 2 of the burn wound and colonic mucosa during resuscitation at 0, 2, 4, 6, and 8 ml/kg/ %TBSA. Paratrend data were analyzed in conjunction with previously reported laser Doppler images of actual burn wound capillary perfusion. With current clinical therapy, continuous monitoring of arterial base deficit revealed repetitive cycles of resolution/worsening/ resolution during burn shock resuscitation. In the rat model, tissue pCO 2 in both burn wounds and splanchnic circulation differed depending on the rate of fluid resuscitation (P

Nature 401, 55–57; 1999 In the second paragraph on page 55, the third sentence is misleading and should read “The yields even exceed those of the empty-cage C84” (without the erroneously inserted text “…the usually most abundant species…”).