Flow Characteristics of Human Erythrocytes through Polycarbonate Sieves.

We used polycarbonate sieves with uniform cylindrical pores (2.4 to 6.8 microns in diameter) to filter suspensions of human erythrocytes (mean major diameter is 7.2 microns) in Eagle-albumin solution. With 6.8-micron sieves the pressure-flow curves are convexed to the pressure-axis at low pressures and become linear with high pressures. With 4.5-micron sieves, however, the pressure-flow relationship is linear throughout the range of study. In both types of sieves, flow rate is reduced progressively with increasing concentration of red blood cells (RBC) over a range of 0.5 to 95 percent. The resistance to flow of RBC suspensions is higher in 4.5-micron than in 6.8-micron pores. With filter pore diameters of 3.0 microns or more, the RBC concentration in the filtrate was 100 percent of that in the solution being filtered, but only 70 percent with 2.4-micron pores. The observed critical pore diameter for 100 percent cell transmission agrees with theoretical calculation based on the assumption that the RBC membrane is deformable but nonextensible. The importance of cell deformation in the passage of RBC's through small pores is shown by the inability of RBC hardened in acetaldehyde to pass pores with 6.8-micron diameter.

Serum lipid response of hypercholesterolemic men to single and divided doses of canned beans.

Dried beans lower serum lipid concentrations in healthy and hyperlipidemic subjects. To determine the effects of canned beans on serum lipid concentrations, 24 hyperlipidemic men ate one of three bean diets for 21 d in a metabolic ward. Diets A and B included 227 g canned beans (120 g beans with 107 g tomato sauce) daily, in a single dose for diet A and in a divided dose for diet B. Diet C included 182 g canned beans (162 g beans with 20 g tomato sauce) daily in a divided dose. All bean diets combined lowered serum cholesterol and triglyceride concentrations 10.4% (p less than 0.001) and 10.8% (p less than 0.025), respectively. Diet B was as effective as diet C, and the groups on those diets had greater cholesterol reductions than did the group on diet A. Serum cholesterol reduction was positively correlated (p less than 0.01) with intake of total dietary fiber and soluble fiber. The ratios of low- to high-density-lipoprotein cholesterol remained constant for all groups. Body weight decreased 1.0-1.5 kg for all groups despite constant energy intakes. Canned beans may make an important contribution to hyperlipidemia management.

Oat-bran cereal lowers serum total and LDL cholesterol in hypercholesterolemic men.

Oat bran lowers serum lipid concentrations in healthy and hyperlipidemic subjects. To determine the effects of a ready-to-eat oat-bran cereal on lipid concentrations, we fed control (corn flakes) and oat-bran cereal diets for 2 wk to 12 men with undesirably high serum total-cholesterol concentrations. Subjects were randomly assigned to one of the two diets upon admission to the metabolic ward. After completing the first diet, subjects completed 2 wk on the alternate diet. Intakes of carbohydrate, protein, fat, and cholesterol were virtually identical on the two diets. The oat-bran cereal provided 25 g oat bran/d. The oat-bran cereal diet compared with the corn flakes diet lowered serum total-cholesterol and serum LDL-cholesterol concentrations significantly by 5.4% (p less than 0.05) and 8.5% (p less than 0.025), respectively. Final body weights on each of the diets were similar. Ready-to-eat oat-bran cereal provides a practical means to incorporate soluble fiber into the diet to lower serum cholesterol.

Discovery and biological activity of orally active peptidyl trifluoromethyl ketone inhibitors of human neutrophil elastase.

Previously we had shown that tripeptidyl trifluoromethyl ketones (TFMKs) possessing an N-terminal diarylacylsulfonamide, such as ICI 200,880 and ICI 200,355, displayed unparalleled protection against the lung damage induced by human neutrophil elastase (HNE) when the inhibitors were administered intratracheally. Since the diarylacylsulfonamides were designed specifically to afford a long residence time in the lung, it was not unexpected that inhibitors from this class of TFMKs were not active when administered orally. Upon evaluating a large number of peptidyl TFMKs possessing a variety of N-terminal groups, several compounds were identified which demonstrated oral activity. Compounds were evaluated for their oral activity by measuring their ability to inhibit the increase in lung weight relative to body weight (Lw/Bw), the increase in red blood cells, and the increase in white blood cells induced by intratracheally administered HNE (100 micrograms/hamster). A number of tripeptidyl trifluoromethyl ketones containing neutral N-terminal groups displayed good oral activity, while those containing basic, acidic, or polar groups did not. Compound 50, possessing an N-terminal 4-(CH3O)C6H4CO group, was particularly effective, reducing Lw/Bw by 77%, red cells by 89%, and white cells by 91% when dosed at 37.5 mg/kg orally. Thus, by modifying the N-terminal group of tripeptidyl TFMKs, inhibitors can be designed which are effective in vivo when administered either orally or intratracheally.

Beliefs and mammography screening.

INTRODUCTION: Breast cancer is a leading form of preventable cancer among women in the United States. Despite improvements in mammography and other early detection techniques, special populations, including older and minority women, continue to experience high incidence and mortality rates. Knowledge, attitudes, and beliefs are ubiquitous constructs in preventive medicine, health behavior, and behavioral epidemiology. These constructs often are used to explain variation in health screening behavior. While all three have been examined in relation to mammography screening, concentration on the single category of beliefs and the relation between specific beliefs and mammography screening practices has remained largely uninvestigated. METHODS: Using logistic regression modeling, we examined the relationship between four individual beliefs and mammography screening in a cross-sectional study of 407 women. RESULTS: After we controlled for confounding factors in a multivariable analysis, belief in the efficacy of early detection in improving breast cancer outcome (odds ratio [OR] = 2.98; 95% confidence intervals [CI] = 1.62, 5.47) and perceived risk (OR = 0.49; 95% CI = 0.26, 0.94) were significantly associated with screening practice. Belief that mammography is dangerous (OR = 0.46; 95% CI = 0.18, 1.18) or painful (OR = 1.25; 95% CI = 0.75, 2.08) was not significantly associated with screening practice. CONCLUSIONS: Information on the relationship between beliefs and screening practices may be used both to understand screening behaviors and to develop targeted strategies to improve mammography compliance.

Continuous transcutaneous oxygen monitoring during an intraoperative cardiac arrest.

A transcutaneous oxygen sensor was used continuously during surgical management of a ruptured abdominal aortic aneurysm. Closed chest compression initiated for intraoperative cardiac arrest gave an inadequate cardiac output on the basis of falling PtcO2 despite transmitted femoral pulses and an excellent PaO2. This discordance provided a rationale for open cardiac massage, which increased the cardiac output and tissue perfusion (PtcO2) needed for successful resuscitation. The PtcO2 sensor provides immediate, non-invasive, and continuous information regarding tissue oxygenation. It reflects the PaO2 in hemodynamically stable patients as well as providing a sensitive indicator for inadequate cardiac output during shock. In patients undergoing cardiopulmonary resuscitation, a falling PtcO2 with an acceptable PaO2 indicates poor tissue perfusion and, in select circumstances, may warrant open cardiac massage.

Functional imaging of the brain in the evaluation of drug response and its application to the study of aging.

Functional neuroimaging techniques including single photon emission computerised tomography (SPECT), positron emission tomography (PET) and functional magnetic resonance imaging (FMRI) can provide insight into the functional connectivity of the human brain in both health and disease, including the effects of aging and drugs on brain function. Neuroimaging measurement techniques can either be direct, using radio-specific ligands, or indirect, using the neurophysiological consequences of pharmacological interventions. Both approaches can be combined with sensorimotor or cognitive activation to examine the interaction between the targeted receptor function and the sensorimotor or cognitive process implicit in the study design. Using radionuclides, PET can provide absolute measurement of cerebral blood flow to regions of interest and can measure changes in cerebral metabolism using labelled fluorodeoxyglucose. PET offered the first opportunity to image brain activation caused by a variety of stimuli and hence to measure the effect of drugs on brain activation. PET also enables the study of drug disposition within the brain. SPECT has been used to study relative changes in cerebral blood flow associated with disease processes and also receptor occupancy. FMRI, by contrast, does not involve ionising radiation and has better spatial and temporal resolution. It is still a relatively new technique and limited by its ability to only measure haemodynamic changes through the blood oxygen level-dependent (BOLD) signal. The effects of aging on drug responsiveness and the effects of drug treatment of diseases associated with old age are relatively unexplored areas of functional neuroimaging research.

Dietary fiber and diabetes: a comprehensive review and practical application.

Diabetes takes an enormous human and monetary toll each year. Current treatment too often revolves around insulin and drug therapy, neglecting diet and exercise. A comprehensive review was undertaken to assess and summarize the effects of dietary fiber on diabetes. Fiber supplement studies with guar, wheat bran, and apple fiber produced mixed results; some studies reported lowered fasting glucose and cholesterol values and less glycosuria. However, many available fiber supplements cause side effects. High-carbohydrate, high-fiber diets providing 55% to 60% of energy as carbohydrates, 15% to 20% as protein, and 20% to 25% as fat and including 50 gm or more fiber daily hold the most potential for long-term use. These diets reduce insulin requirements, improve glycemic control, lower fasting serum cholesterol and triglyceride values, and promote weight loss. Studies show good long-term adherence with these diets. Dietitians assume primary responsibility for educating individuals on the benefits and use of high-carbohydrate, high-fiber diets. Diets must be individualized, with special modifications for obesity, hyperlipidemia, or physiological states such as pregnancy and lactation. Widespread use of high-fiber diets will ultimately improve metabolic control and decrease health care costs for thousands of diabetic and non-diabetic individuals.

The impact of kin, friend and neighbor networks on infant feeding practices. Cuban, Puerto Rican and Anglo families in Florida.

This paper uses social networks as the major conceptual device to examine the impact of relatives, friends and neighbors on infant practices, Kim, friend and neighbor networks of Cuban, Puerto Rican and Anglo families in Dade County, Florida are described, noting inter-ethnic differences in network members who provide respondents with infant feeding advice and assistance. The geographical proximity of influential network members is shown to effect the impact that health care professionals have on mothers' decisions about feeding practices. Network influences on specific feeding practices also are discussed. Kin, friend and neighbor networks are shown to have a significant impact on decisions surrounding breastfeeding, bottle-feeding, use of sucrose supplements and the time to introduce solid foods into the baby's diet. Network member's advice and encouragement appears to contribute to a successful lactation experience. Applying the Fisher's exact test to a small subsample, however, does not yield a significant association between presence or absence of network support and lactation outcome.

Differences in vitamin A content of enteral feeding solutions following exposure to a polyvinyl chloride enteral feeding system.

This research was conducted to determine if there were significant differences in the vitamin A content of two enteral feeding solutions following timed exposure to a polyvinyl chloride (PVC) enteral tube feeding system. This study took place in the laboratory setting with procedures designed to simulate clinical conditions with respect to rate of flow and time of exposure. Feeding solutions (Ensure Osmolite and Vivonex High Nitrogen) were sampled, placed in PVC feeding system pouches (Vivonex Delivery System, Norwich-Eaton Pharmaceuticals, Norwich, NY) and permitted to drip from the pouches at a constant rate. Solution remaining in the pouches was sampled at intervals for a period of six hours, and all samples were analyzed for Vitamin A content using spectrophotometric methods. Statistical analysis of the data indicated no significant difference in Vitamin A content of either feeding solution following six hours of exposure to a PVC enteral tube feeding system.

Quality assessment of tetanus prophylaxis in the wounded patient.

New guidelines on tetanus prophylaxis in wound management have been prepared by the American College of Surgeons and are available in a poster format or in bulletins. The purpose of this study was to determine the impact of these educational brochures on tetanus prophylaxis in a hospital setting. The results of this study indicate that these informational brochures and posters had insignificant impact on the quality of prophylaxis against tetanus in our hospital. Innovative programs of information exchange and quality assurance are urgently needed to improve the delivery of health care.

Improving the accuracy of burn-surface estimation.

A user-friendly computer-assisted method of calculating total body surface area burned (TBSAB) has been developed. This method is more accurate, faster, and subject to less error than conventional methods. For comparison, the ability of 30 physicians to estimate TBSAB was tested. Parameters studied included the effect of prior burn care experience, the influence of burn size, the ability to accurately sketch the size of burns on standard burn charts, and the ability to estimate percent TBSAB from the sketches. Despite the ability for physicians of all levels of training to accurately sketch TBSAB, significant burn size over-estimation (p less than 0.01) and large interrater variability of potential consequence was noted. Direct benefits of a computerized system are many. These include the need for minimal user experience and the ability for wound-trend analysis, permanent record storage, calculation of fluid and caloric requirements, hemodynamic parameters, and the ability to compare meaningfully the different treatment protocols.

Health professionals and breastfeeding counseling: client and provider views.

Health care providers are the most influential and trusted source of information about breastfeeding, yet many are neither prepared nor able to provide good breastfeeding counseling to their clients. This paper reports findings on low-income mothers' and on providers' perceptions of professional breastfeeding counseling. Data collection included focus group discussions with mothers recruited from public health department clinics in the Southeast USA and who were stratified by age, parity, rural/urban residence and feeding method, and focus groups and individual interviews were conducted with health care providers from the same geographic area. The results of the study indicate a gap between the promotion and support processes for breastfeeding, and point to areas where breastfeeding counseling can be strengthened.

Electric burns of the oral cavity.

Low-voltage electric burns are the leading cause of electric burn injury in childhood and can result in an injury to the oral cavity that can heal with a noticeable deformity. The mechanisms of burn injuries to the oral cavity are either due to the electric arc or current or both. Electric burns of the oral cavity can involve the lip, tongue, mucous membranes, and underlying bone. Therapy for these injuries should include management of systemic sequelae and treatment of the local burn injury. Our therapeutic approach to this injury is dictated by the pathophysiology of the electric burn of the oral cavity.

Interactions between blind parents and their young children.

Observations on four families with blind parents and young sighted children showed that relations between the children and their parents were remarkably little affected by the parents' handicap. Many of the characteristics of normal parent-child interaction, both verbal and non-verbal, seem to be readily adaptable to the special circumstances of blindness. Thus, it appeared that the parents were well able to participate in various kinds of social exchange, som of which had a seemingly strong visual element.

Efficacy of burned surface area estimates calculated from charts--the need for a computer-based model.

An accurate estimation of burn surface area is needed to correctly calculate initial fluid resuscitation, nutritional requirements, prognosis, and comparisons of treatment protocols among burn centers. The following experiment was conducted to test the accuracy of physicians compared to a computer-assisted method. Twenty-seven physicians were asked to estimate the per cent of burned surface area from an adult patient diagram. Physicians were found to consistently overestimate the percentage of burned surface area. The average physician estimate was 42% compared to 29.6% calculated by a computer-assisted program. The degree of error between physician estimates and actual TBSA burned is significant and may critically affect patient management. Additional benefits of computer assistance include a permanent record of injury, burn wound trend analysis, and meaningful statistics involving morbidity, mortality, and comparative treatment protocols among burn centers.