Neurohumoral activation during exercise in congestive heart failure

Neurohumoral factors were assessed in 14 subjects with chronic, stable New York Heart Association functional class II or III congestive heart failure and nine comparably aged normal subjects at rest and during moderate (50 W) and strenuous (100 W) upright exercise. Heart failure was associated with elevated plasma renin activity and plasma antidiuretic hormone (ADH) concentrations at rest. However, plasma renin activity almost doubled (from 4.7 +/- 0.6 to 8.4 +/- 1.1 ng/ml per hour) during strenuous exercise in subjects with heart failure, and changed only minimally in normal control subjects. Plasma ADH concentration did not change during exercise in the presence of heart failure, but rose in normal subjects during strenuous exercise to levels comparable to those of subjects with heart failure. Similar plasma osmolality values were present in both groups. Circulating norepinephrine concentrations were insignificantly elevated by heart failure both at rest and during exercise, and plasma epinephrine concentrations were similar. These findings suggest independent neurohumoral activation during exercise in the presence of congestive heart failure, with predominant activation of the renin-angiotensin-aldosterone axis.

A study of dynamic load balancing in a distributed system

This paper presents a study of a distributed system consisting of a number of hosts connected by a local area network. The system model is based on the LOCUS distributed file system. The LOCUS file system allows replicated files, and the synchronization policy is enforced by the use of the Centralized Synchronization Sites (CSS). All requests to open a file for access must be sent to the file's CSS which checks for access conflicts. Our simulation model allows process migration. The focus of this study is on load balancing as applied to optimal process and read site placement. An algorithm is proposed that increases system performance through load balancing. This algorithm uses data collected by the system on which to base its decisions. The characteristics of the algorithm and their effects on system performance are analyzed and discussed.

Potential methods for predicting tumor radiocurability

Several predictors of tumor radiocurability are already integrated into clinical practice, for example, tumor size, gross morphology (that is, infiltrative or exophytic), histologic type and grade. These are nonspecific and relatively imprecise. The aim of research into predictive assays is not only to refine the discrimination of existing predictors, but also to suggest specific experimental approaches for overcoming tumor radioresistance in individual patients. Two broad categories of predictive assays can be defined: direct and indirect measurement of tumor cell survival and/or repair capability following irradiation, and measurement of cellular and extracellular parameters affecting radiosensitivity. The ongoing research at The University of Texas M. D. Anderson Hospital is overviewed to illustrate potential methods for predicting radiocurability.

Alcohol and drug use among "street" adolescents

Studies of adolescent alcohol use typically sample intact high school populations. This study assessed "street" adolescents alienated from the mainstream educational system. Despite recent optimism regarding adolescent substance use, these respondents showed considerable alcohol consumption, drinking to get drunk, and problems. The major correlates of substance abuse were "personal" drinking motives, expectancies of alcohol effects and peer behavior. Thus, adolescents who would not appear in typical studies showed much stronger alcohol involvement than the general population, with individual differences best accounted for by attitude variables relevant to a "stress-vulnerability" approach to substance abuse.

Detection of an abdominal aneurysm by indium-111 platelet imaging

The authors report a case in which In-111 platelet imaging provided uniquely useful information in the discovery of an abdominal aortic aneurysm. This case illustrates the potential usefulness of this procedure in the detection of unsuspected sites of thrombogenic vascular disease.

Evaluation of right subphrenic fluid collections with emission computed tomography: an experimental study

An animal model to study subphrenic fluid collections is presented. Performance of single photon emission computed tomography (SPECT) for detection of subphrenic fluid collections was compared to that of liver-lung scintigraphy and transmission computed tomography (TCT). TCT detected a water volume of 25 ml in the right subphrenic space. This volume was barely seen using SPECT and not detectable on scintigraphy. Differences in performance of the three imaging modalities are discussed.

Predicting radiocurability

Several predictors of tumor radiocurability are already integrated into clinical practice, e.g., tumor size, gross morphologic features (i.e., infiltrative or exophytic), histologic type, and grade. These are relatively imprecise, however, and none is specific. The aim of research into predictive assays is not only to refine the discrimination of existing predictors but also to suggest specific experimental approaches for overcoming tumor radioresistance in individual patients. Two broad categories of predictive assays can be defined: direct and indirect measurements of tumor cell survival and/or repair capability following irradiation and measurement of cellular and extracellular parameters affecting radiosensitivity. Examples from ongoing research at the University of Texas M. D. Anderson Hospital using one technique from each category (the micronucleus assay and flow cytometric analysis of tumor cell proliferation kinetics and ploidy) are used to illustrate potential methods of selecting patients for fast neutron radiotherapy.

Nasal carriage and antibiotic susceptibility of Staphylococcus aureus in general practice

The incidence of nasal carriage of Staphylococcus aureus and the in vitro susceptibility of isolates to fusidic acid, penicillin, erythromycin, methicillin and tetracycline was determined in 204 patients who had been treated previously with a short course of a topical preparation of Fucidin for acute skin sepsis, and in an equal number of control subjects. Staphylococcus aureus was isolated from 36 per cent and 34 per cent of patients in the Fucidin and control groups respectively. Only one of the 144 isolates was resistant to fusidic acid. Short, single courses of topical therapy in general practice are unlikely to be epidemiologically hazardous in the long term. Evidence of possible cross-infection in general practice was obtained.

Venous pressures during simulated Bier's block

Venous pressures in the forearm veins during the simulated performance of intravenous regional analgesia were measured. Pressures obtained equalled or exceeded the recommended occluding pressure of the tourniquet. This finding is proposed as one of the possible reasons for the occasional observation that convulsions may occur during Bier's block despite the presence of an intact tourniquet system.

Methylprednisolone sodium succinate (Solu-Medrol) in the treatment of typhoid perforation (a preliminary report)

It is now universally accepted that treatment of typhoid perforation must be surgical. In spite of this and the use of antibiotics, the mortality rate is still high. Previous observations that some patients with typhoid perforation present with features suggestive of septicaemia and septic shock made us conduct a clinical trial with methylprednisolone sodium succinate (Solu-Medrol) in treating this disease. Our data show that use of this drug in addition to antibiotics and early surgical intervention reduces the mortality rate in typhoid perforation.

Simultaneous three color and electronic cell volume analysis with a single UV excitation source

We have adapted an Ortho ICP-22 flow cytometer (Ortho Instruments, Westwood MA) for the simultaneous measurement of three independent fluorochromes and cell volume. This has been accomplished by the addition of a third photomultiplier tube and the development of a new electronic cell volume (ECV) flow cell. Cells are first analyzed as they pass through the 100 U ECV aperture and are then excited approximately 15 musec later by the 365 nm mercury are beam reflected by a 400 nm dicroic mirror. Independent blue, green and red signals can be associated by a delay circuit to the ECV signal from the same cell. We have developed this system as an aid in the analysis of tumor cell and macrophage heterogeneity and differentiation. The choice of stain combinations to be used is extremely flexible and permits the analysis of a wide range of enzyme activities in conjunction with DNA/RNA and phagocytic probes. Data presented indicates the value of this approach in identifying the presence of plasminogen activator-like activity in both tumor and inflammatory cells within a malignant effusion as well as the quantitative expression of a number of markers of macrophage differentiation. Although the described techniques have been developed on a mercury arc instrument, they can be used equally well with cell sorters.

Age-related differences in isometric and dynamic strength and endurance

To measure age-related skeletal muscle changes, 30 healthy, moderately active women performed isometric and dynamic strength and endurance tests of their left quadriceps femoris muscle groups. Fifteen of the subjects were ages 20 to 29 years and 15 were ages 50 to 80 years. A cybex II isokinetic dynamometer was used to measure the torque output isometrically with the knee at 90 degrees of flexion on three trials. In addition, each subject performed three trials from 90 degrees of knee flexion to full knee extension and back to 90 degrees of knee flexion with the velocity of the isokinetic dynamometer set at 10 rpms. Endurance time was calculated to be the length of time a torque output of at least 50 percent of the maximal strength could be maintained. The t tests done revealed a significant difference between the two groups on isometric and dynamic strength, while no significant difference was found on isometric or dynamic endurance. Statistically correcting for the extraneous variables, height and weight, through a partial correlation revealed a significant negative correlation between age and strength. The younger subjects had higher torque outputs, both isometrically and dynamically, than the older subjects. The same partial correlation between isometric endurance and age and dynamic endurance and age demonstrated no significant correlation. The fact that endurance did not change in this older population while strength did may be the result of fast-twitch and slow-twitch muscle fibers changing with age.

Single-photon emission tomography with a 12-pinhole collimator

To assess the advantages of more complete angular sampling and of more views in the tomographic reconstruction process, tomographic imaging with a 12-pinhole (12PH) collimator has been compared with 7-pinhole tomography (7PH). The 12PH system gives a 50% increase in sensitivity but resolution degrades more rapidly with depth. The 7PH and 12PH systems provide similar accuracy of detection of lesions in a myocardial ring phantom. The 7PH images, however, demonstrated more noise and "ripple" artifacts. The 12PH system offers a larger reconstruction volume and generates fewer artifacts when the collimator is misaligned with the myocardial long-axis, thus making patient positioning less critical than with 7PH. A disadvantage is that individual views are minified by the 12PH collimator, and a 256 X 256 image matrix should be used during image acquisition to limit digital sampling errors.

Slow late myocardial clearance of thallium: a characteristic phenomenon in coronary artery disease

We extended the quantitative seven-pinhole method to follow the dynamics of thallium redistribution after exercise. We observed a pattern of slow late thallium clearance that appears to be characteristic of myocardium supplied by obstructed coronary arteries. In 28 subjects, quantitative thallium scintigrams (seven-pinhole tomography, circumferential count profiles) and blood samples for thallium concentration were taken immediately, 2 hours and 4 hours after maximal treadmill exercise. Twenty subjects had coronary artery disease (CAD) and eight were normal. The rate of thallium clearance from the blood (TCB) was compared with the rate of thallium clearance from each segmental region of myocardium (TCM, derived by ratioing corresponding segments of the absolute circumferential count profiles) between the 2- and 4-hour images. In seven of the eight normal subjects, TCM exceeded TCB in all regions of all images (specificity 88%). Seventeen of the 20 CAD patients had at least one region where TCM was less than TCB (sensitivity 85%). Of the 13 patients with multivessel CAD, 11 had multiple regions with TCM less than TCB. Using this criterion, we detected 31 of 39 obstructed coronary arteries. Of the 37 regions that were abnormal by this analysis, 30 corresponded to obstructed coronary arteries. In contrast, while conventional circumferential count profile analysis also was abnormal in 17 of the 20 CAD patients, it diagnosed multivessel CAD in only five of the 13 patients that had it. These results show that slow late thallium clearance from myocardium is characteristic of regions of myocardium supplied by diseased coronary arteries and that observation of this phenomenon may improve diagnostic sensitivity for the presence of multivessel CAD.

Faculty supervision of residents in an internal medicine practice

This study examines the supervision of residents by faculty members in an outpatient internal medicine practice. For the study, the investigators developed a methodology to analyze the cognitive content and the focus of residents' thoughts during conversations between faculty members and residents. The residents also identified characteristics of productive and less productive exchanges with the faculty. The study shows that both residents and faculty members use the majority of their part of conversations to present information. Residents in early training appear to be more challenged by diagnostic issues, while residents later in training are more concerned with therapy and management. The study results suggest that effective supervision may relate more to the ability of faculty members to display their reasoning as they present information to residents than to the quantity and types of questions they pose to residents.

Industrial relations: conflict and communication

Organisational roles and systems are a reflection of professional group norms, says Tony Johnson of the West Midlands RHA personnel division. He suggests that professionals need to be encouraged to be aware of how their expectations affect their particular service, and thus the patient.

Allocation of time and resources by married couples approaching retirement

The work and retirement decisions of husbands and wives are likely to be made jointly as they allocate their available resources. This article models the allocation of family wealth and family members' time over the lifetime of the unit. The first section reports simulation results that illustrate the relationship between the value of members' time in both market work and the production of home services. The model is then tested by means of the Retirement History Study for 1969-73. The estimation is conducted by employing a simultaneous logit model of labor-force participation by the husband and wife. Principal findings are: (1) Individuals respond positively to increases in their own wage rate but tend to reduce labor-force participation as the wage rate of their spouse increases, (2) the health of the husband is an important determinant of his labor-force participation, and (3) the probability that a person will be in the labor force is raised if the spouse is employed.

Particle size distribution analysis for the rapid detection of microbial infection of urine

The accuracy and practicality of particle size distribution analysis for rapid screening of urine specimens are assessed. Six hundred urines were subjected simultaneously to routine bacteriological examinations and particle size distribution analysis using a Coulter Counter (ZBI) linked to a C1000 Channelyzer. There was complete agreement in the results of 593 (98.8%) specimens. Characteristic profiles of various bacterial species in infected specimens were consistently obtained. This system can easily be linked to any existing computer reporting in a district hospital laboratory, and the results of negative specimens (70--80%) can be obtained within 5--10 minutes.

Chloramphenicol and phenobarbitone--a drug interaction

Two infants with meningitis who were treated with phenobarbitone and high-dose chloramphenicol showed progressive falls in the peak blood levels of chloramphenicol. A standard chloramphenicol dose of 50 mg/kg daily would have produced subtherapeutic blood levels after only a few days. The importance of measuring serial blood chloramphenicol concentrations is stressed.

Isolation of salmonella using a standardised inoculum and a rotary plating technique

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Transcallosal approach to third ventricle tumor: case report. Partial removal of an infundibuloma (grade I astrocytoma arising from the floor of the third ventricle)

A care is described of an astrocytoma grade 1 arising from the floor of the third ventricle, operated upon transcallosally. No disconnection symptoms were produced. Five years later the patient has above normal intelligence and is attending school at normal grade level in spite of a CT scan suggesting recurrence of the tumor.

Detection of beta lactamase activity of Haemophilus influenzae

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Crystals, paracrystals, and rigid tubules in multiple sclerotic brain and spinal fluid

Brain and spinal fluid were obtained post mortem from an individual with multiple sclerosis who died following carbon monoxide inhalation. Electron microscopic examination of the plaque region revealed a crystalline structure (repeat unit 380 to 410 A) within rough endoplasmic reticulum of astrocytes, a paracrystal (160 to 220 A) within the cytoplasm of astrocytes, and rigid tubules (outer diameter 320 to 450 A) within a cell in the lumen of a capillary. The paracrystal was enclosed by the glial fibrils. A second crystalline material was observed within cells in the 15,000 X g pellet from spinal fluid. The ultrastructural pattern of this second crystal was generated by three sets of parallel lines; a given set was intersected by the other two sets. The crystal had only two different repeat units (410 to 450 A; 310 to 350 A) since the smaller dimension was common for two sets of lines. The two crystals were large; the one in astrocytes had a length of 52,000 A and that in spinal fluid sediment was 62,000 A. These structures were observed in the one multiple sclerotic brain obtained at autopsy but were not detected in multiple sclerotic brains that had been frozen for extended periods. Plaque regions and grossly normal white matter were homogenized and the 1000 X g supernatant of this material was fractionated in a continuous CsCl-sucrose density gradient. Long tubules (320 to 500 A diameter) were observed in the 1.24 to 1.26 density region. The major proteins of the 1.24 to 1.26 fraction had molecular weights clustered at 40,000 to 45,000, 88,000 to 130,000, and 300,000.

Isolation of dendrodendritic synapses from swine olfactory bulbs

Dendrodendritic synapses from swine olfactory bulbs were isolated by homogenization of the gray layer, followed by centrifugation at 1000 X g. Centrifugation of the supernatant at 10,000 X g revealed that all dendrodendritic synapses had pelleted at 1000 X g. The upper portion of the 1000 X g pellet was further purified in a discontinuous sucrose gradient, and each resultant fraction was examined by electron microscopy. The dendrodendritic synapses band below the 1.2-1.4 M sucrose interface, appear to be minimally contaminated with other membranous elements, and have retained their adhesions. The banding pattern and relative amounts of proteins from dendrodendritic synaptosomes were very similar to those of axonal synaptosomes as determined by electrophoresis on polyacrylamide gels containing sodium dodecyl sulfate (SDS) and 8 M urea.

Routine radioimmunoassay of plasma testosterone, and results for various endocrine disorders

We describe a modification of published methods for radioimmunoassay of plasma testosterone. This simpler method involves no chromatographic steps, and the necessary reagents, including tritiated testosterone and testosterone anti-serum, are commercially available. A digital computer is used for the calculation. Without difficulty, a technician can complete 100 assays in three working days. Mean testosterone concentrations (plus or minus 2 SD) in the plasmas of 21 normal men and 26 women with a normal menstrual cycle were 684 plus or minus 300 and 45 plus or minus 20 ng/dl, respectively. Within- and between-assay precision (coefficient of variation) were 5.2% (n = 29) and 6.7% (n = 26), respectively. We have assayed more than 1000 samples during the past year. We give data on the concentrations of testosterone in plasma of patients with various endocrine disorders.