Influence of electrical stimulation of the substantia nigra on spontaneous activity of raphe neurons in the anesthetized rat

Recent studies of afferent connections of the anterior raphe using the horseradish peroxidase technique have demonstrated a major projection originating in the substantia nigra (SN). The present acute electrophysiological study examined the influence of stimulation of the afferent on the activity of individual neurons in the raphe of the posterior midbrain and anterior pons (n = 51), and of a control group of cells (n = 15) located 2 mm lateral to the raphe. The predominant effect of SN stimulation at 0.1-1.0 mA, 1 Hz or 10 Hz, was suppression of raphe activity, with 63% of the cells showing cessation of firing following SN pulses and only 8% showing excitation. The average duration of suppression was 200 msec at 1 Hz and 38 msec at 10 Hz. In contrast, 40% of the lateral cells were excited, with 27% of the cells showing suppression. The mean duration of total suppression of lateral cell firing was 61 and 17 msec at 1 and 10 Hz, respectively. The results from the raphe cells are consistent with recent reports of stimulation of other forebrain and brainstem afferents to the raphe in which suppression of raphe activity was the main effect.

The electrocardiogram in asymmetric septal hypertropy

Electrocardiograms and echocardiograms in 44 patients with asymmetric septal hypertrophy were reviewed. Patients with asymmetric septal hypertrophy had incidences of left ventricular hypertrophy (33 percent; 16/44) and left atrial hypertrophy (25 percent; 11/44) by ECG that were less than in a group of patients with significant aortic stenosis (70 percent [31/44] and 64 percent [28/44], respectively). Left ventricular hypertrophy on the ECG was associated with a greater septal-posterior wall thickness ratio in asymmetric septal hypertrophy. A small Q wave in lead V4 or a ratio of the R-wave to the S-wave amplitude (R/S ratio) of greater than 0.20 in lead V1 was found in 14 of 44 patients with asymmetric septal hypertrophy but in no patients with aortic stenosis. The mean corrected Q-T interval (Q-Tc) of patients with asymmetric septal hypertrophy was prolonged, and the mean Q-Tc of patients with aortic stenosis was normal. The distinctive findings of an R/S ratio of more than 0.2 in lead V1 and Q waves in lead V4 in asymmetric septal hypertrophy have clinical significance, and the prolonged Q-T interval may relate to sudden death.

Nursing care of oncology patients receiving chemotherapy

As part of a research effort directed at identifying specific nursing activities related to the subsequent health status of the patient, this study explored relationships between selected nursing activities and patient outcomes for the oncology patient who was receiving chemotherapy. The study was correlational in design and descriptive in nature. Included in the study were 57 subjects from oncology and/or medical units in public and private nonprofit general hospitals. Human subjects' clearance was obtained for the study in each participating hospital. Data were collected primarily by means of patient and nurse responses to self-administered questionnaires. In the initial phase of data analysis, zero-order correlations were obtained for each pair of nursing activity and patient outcome variables. In addition, to identify relative contributions of different nursing activities to the health status of patients, regression analyses were performed in selected situations. The content and the quality of the explanation of the treatment and care regime were observed to be correlated positively with the patient's self-esteem. The quality of the explanation was observed to be positively related to the patient's knowledge base. Involving the patient in his care plan and giving him control over the activities of the day were positively correlated with importance of having things explained to him.

Diastolic left ventricular pressure-volume and stress-strain relations in patients with valvular aortic stenosis and left ventricular hypertrophy

Left ventricular (LV) chamber and myocardial stiffness were determined in 17 patients, four subjects with normal LV function and 13 subjects with valvular aortic stenosis and concentric myocardial hypertrophy, using simultaneous catheter micromanometry and LV cineangiography. Pressure (P), volume (V), and wall thickness (h) were measured. Variability in both chamber and myocardial stiffness parameters was found with five of the aortic stenosis patients (Group 1, left ventricular end-diastolic pressure = 15 +/- 2 (SEM) mm Hg) exhibiting normal values for end-diastolic dP/dV and dP/dV/V, for chamber stiffness constants (a,a') derived from P-V and normalized P-V relations, respectively, for end-diastolic myocardial elastic stiffness (ES or EE, where S = spherical model and E = ellipsoidal model) at the midwall of the minor axis circumference, and for the myocardial stiffness constants (KS or KE) of the circumferential stress-strain relation. Eight other patients with aortic stenosis (Group II, left ventricular end-diastolic pressure = 20 +/- 3 (SEM) mm Hg) exhibited significant increases in end-diastolic dP/dV,dP/dV/V,ES and EE and a tendency for increase in the chamber stiffness constants (a,a') and myocardial stiffness constants (KS, KE). These observations suggest that concentric increase in muscle mass (increase in wall thickness/minor axis radius ratio and wall volume/chamber volume ratio) is an important determinant of elevated mid- and late diastolic pressures in patients with valvular aortic stenosis, while concurrently mitigating increases in both systolic and diastolic wall stress. In some patients with aortic stenosis, however, diastolic filling pressures are elevated more severely, not only as a result of concentric hypertrophy, but also in response to augmented muscle stiffness. Reversibility of increased ventricular diastolic stiffness and elevated filling pressures was documented as concentric hypertrophy regressed post-aortic valve replacement in one patient, suggesting that fibrosis is not invariably the cause of enhanced myocardial stiffness in this secondary and compensatory form of hypertrophy.

Evaluation of the in vivo function of the Hancock porcine xenograft in the aortic position

We evaluated the vivo hemodynamic function of the stent-mounted glutaraldehyde-fixed porcine xenograft in 23 patients who had undergone aortic valve replacement from 2 days to 24 months prior to the study. Functional aortic valve orifice areas for the porcine xenograft ranged from 0.58 to 3.0 sq. cm., the average area being 1.36 sq. cm. Six patients had calculated prosthetic valve orifice areas less than 1.0 sq. cm. Valve orifice area did not correlate significantly with valve size or the time interval from surgery to postoperative study. Left ventricular stroke volume showed a significant, positive correlation with calculated xenograft orifice area. Systemic thromboembolism was not encountered. One patient required reoperation for xenograft stenosis caused by dense fibrin deposition on the aortic leaflets. We conclude that use of the stent-mounted glutaraldehyde-fixed porcine xenograft can be associated with significant functional stenosis which may be related to annulus size or inertial properties of the valve. These factors should be taken into consideration when considering use of the stent-mounted glutaraldehyde-fixed porcine xenograft in individual patients.

Mechanism of action of the cro protein of bacteriophage lambda

The mechanism of action of cro protein was probed by measuring its ability to protect DNA against methylation by dimethyl sulfate and its effect on transcription in vitro. The cro protein binds to the same three sites in the right operator (OR) of bacteriophage lambda DNA as does the lambda repressor. Dimethyl sulfate protection experiments reveal major groove contacts for both proteins, and cro protein protects from methylation a subset of those purines protected by lambda repressor. These experiments also show that the relative affinity of these two proteins for the three operator sites is different: whereas lambda repressor binds with an affinity OR1 greater than OR2 greater than OR3, the order for cro protein is OR3 greater than (OR1, OR2). As predicted by these results, cro protein, like the lambda repressor, blocks in vitro transcription of cI and cro from the two divergent promoters that overlap OR. Also as predicted, transcription of cI is turned off at lower cro protein concentrations than is transcription of cro, whereas the opposite order of repression is obtained with lambda repressor. These results describe the molecular mechanism of cro protein action and show that two regulatory proteins can bind to the same three adjacent sites in DNA with markedly different consequences.

Thryo-endocrine pathology, obstetric morbidity and schizophrenia: survey of a hundred families with a schizophrenic proband

This preliminary communication reports that the mothers of 104 schizophrenic patients had: (1) a significantly higher incidence of thyroid disease than a carefully matched control group; (2) significantly more abortions, still-births and greater infant mortality. The findings and possible relevance of thyroid disease to schizophrenia are discussed. Three prospective studies currently in progress are outlined.

Mixed-valence cytochrome oxidase-formate complex. A steady-state intermediate

At neutral pH, formate binds to the haem a3 component of cytochrome c oxidase to give a complex that reacts differently from the non-liganded enzyme with reducing agents. Addition of sodium dithionite to the formate complex leads directly to the formation of the fully reduced species, whereas reduction with ascorbate/tetramethylenephenylene-diamine can lead to the production of a mixed-valence species. The stability of this mixed-valence form was studied, and the species appears to represent a 'steady-state' situation that is stable only in the presence of an excess of O2 and reducing equivalents. Characterization of the mixed-valence complex by electron paramagnetic resonance and magnetic circular dichroism reveals the presence of reduced low-spin haem a together with reduced detectable copper and high-spin ferric haem a3.

Treatise on aeromedical evacuation: I. Administration and some medical considerations

Well conceived administrative procedures must be considered the backbone of a good, strong aeromedical evacuation system. These procedures must insure 1) centralized control of patient transportation by aircraft, 2) specialized medical attendants and equipment for inflight medical care, 3) facilities for limited medical care of patients entering, en route in, or leaving the system, and 4) communications with destination and enroute medical facilities concerning patient transportation. There are no absolute contraindications to aeromedical evacuation. However, patients with the following conditions require special consideration. Such conditions are 1) severe anemia, less than 2.5 million RBC/cc or less than 7.0 g hemoglobin/100 ml, 2) respiratory embarrassment, and 3) trapped gas within any of the body cavities. Medical problems in aeromedical evacuation defy resolution only when patient preparation has been improper. When the patient is properly evaluated, then unnecessary, costly, hazardous, and special flights are avoided. Aeromedical evacuation presents no problem so long as one remembers that man is adapted for life at or near sea level and that changes in pressure with increasing altitude affect his physiological processes. This invisible barrier will continue to challenge human ingenuity in the conquest of high altitude.

Treatise on aeromedical evacuation: II. Some surgical considerations

Preventive medicine is the primary responsibility of every physician. When prevention fails and therapeutic measures are required, the initial approach tends to be along a conservative line. When this approach fails, surgical intervention becomes a necessity. Surgical patients, both pre- and post-surgical, may be moved by aircraft providing that one is aware of the hazards in a hostile atmosphere in which pressure and temperature change with increasing altitude. Air or gas trapped in the body cavities expands in direct proportion to the decrease in pressure. This increased volume becomes significant at 5500 m, where the volume of air or gas in the body is doubled. Quite apart form intense discomfort and actual pain caused in certain types of injury, this expansion of gas at high altitude may constitue a real danger, such as in the probability of rupturing a recently sutured intestine and, in cases of pneumothorax, by disturbance of cardiopulmonary dynamics. Thus, aeromedical evacuation of the surgical patient becomes a challenge to those responsible for the medical care between the originating and destination hospitals.

Two years of routine patient movement in the U.S.A. (Jan. 1974-Dec. 1975)

During a 2-year period, Jan. 1974-Dec. 1975, a total of 102,547 routine patients were aeromedically evacuated from an originating medical facility to a destination hospital within the Continental United States (CONUS). It is the policy of the Department of Defense (DOD) that, in both peace and war, the movement of patients of the Armed Forces shall be accomplished by airlift when airlift is available and conditions are suitable for aeromedical evacuation, unless medically contraindicated. The DOD Regulation 4515.13-R states that a routine patient will be delivered to the destination hospital within 72 h after pickup from aerial ports or from the originating CONUS medical facility. During this 2-year period, 66% of all patients moved were delivered to their destination hospital the same-day they were picked up and 93% of all patients were delivered to their destination hospital within the 72-h DOD criteria for routine patients. In order to reach the destination medical facility, many patients had to remain overnight (RON) at an aeromedical staging facility (ASF). Contributing factors were weather, aircraft maintenance problems, expiration of the crew duty day, patients originating overseas, and patients moving out of originating areas and requiring a second mission to reach the destination hospital.

Recent trends in sex mortality differentials in the United States

Since 1920, American men, to an increasing degree, have experienced higher levels of mortality than American women for virtually all causes of death at almost every age. Recently, several authors have asserted that there is evidence of a change in these trends, caused primarily by rises in the levels of female mortality. Using age-adjusted death rates and data for the most recent years available (1960-1974). This paper shows that most female death rates are either stable or falling, and that the sex mortality differential for all causes except lung cancer is either stable or increasing.