Effect of some physiological factors and pharmacological agents on left ventricular function in man

In recent years, significant conceptual advances have helped to formulate a broad scheme of the mechanisms which regulate ventricular function. Likewise, methodological advances now enable a wide range of haemodynamic measurements to be made in human subjects, with reasonable precision and relative ease. It has thus become possible to relate changes in several haemodynamic variables recorded simultaneously. Although it is still not feasible to estimate the functional competence of the left ventricle (or the heart as a whole) in absolute terns, the qualitative changes can now be assessed with greater confidence. The studies reported here were designed to investigate the changes in left ventricular performance in man during dynamic exercise and following the administration of two pharmacological agents used in clinical practice. The two pharmacological agents, morphine and propranolol, were selected for different reasons. Morphine was chosen in order to determine the circulatory effects that may be attributable to the drug and thereby provide, if possible, a rational basis for its use in the treatment of acute left ventricular failure. The therapeutic efficacy of morphine in this disorder is widely acknowledged, but to date no attempts, other than the one reported here, seem to have been made, (or at least none reported) to delineate the precise mode of action of this drug in the treatment of acute left ventricular failure. A detailed investigation was, therefore, designed to study the haemodynamic changes, with particular reference to left ventricular function, following an intravenous injection of morphine in therapeutic amounts. The report on this study forms the subject matter of Chapter IV. The other pharmacological agent used was propranolol, which is an adrenergic JS-receptor blocking agent. It is generally agreed that the sympathetic nervous system (and the adrenal medulla) dominates in the regulation of the cardiovascular response during dynamic exercise. Since the sympathetic influence (both chronotropic and inotropic) on the heart is mediated through ^-receptors (Ahlquist, 1948), it was felt that with the help of propranolol it should be possible to assess the importance of the sympatho-adrenal system in the regulation of cardiac performance during dynamic exercise. A study was, therefore, designed to investigate the haemodynamic changes during supine leg exercise before and after ^-adrenergic block with propranolol. The report on this investigation is presented in Chapter V. An assessment of the changes in left ventricular performance rg supine leg exercise, which has been used as the standard physiological stimulus, was also undertaken in the course of the study reported in Chapter V. In Chapter I a summary of the present concepts (and some controversies) regarding the regulation cf left ventricular performance is presented. Also Included in this chapter is additional information relevant to the understanding of left ventricular function and the methods that may be used to assess this. A detailed critique of the methods used is given in Chapter II. Since it was not feasible to measure either end-diastolic fibre length or end-diastolic pressure in the left ventricle, the mean pulmonary wedge pressure has been used as an indirect estimate of left ventricular end-diastolic pressure and hence end-diastolic fibre length. It was felt necessary to determine the confidence with which the mean pulmonary wedge pressure could be used as an estimate of left ventricular end-diastolic pressure. To this end, therefore, another study was designed and the report on this is presented in Chapter III. A brief comment on the statistical methods used is given in the appendix. Since this thesis is being presented In two volumes, it was thought best, for ease of reference, to Include all the tables and references in the companion volume

Evidence for long-term variability in the ultra high energy photon flux from Cygnus X-3

A time-correlation analysis of atmospheric Cerenkov pulses by a wide-angle photomultiplier system was previously shown to have present in it a nonrandom component which seemed associated with the Right Ascension (RA) range approx. 20+or-04h. A recent examination of multi-muon events recorded by a photon-decay detector shows a similar time-dependent effect, closely matching the previous results, supporting the suggestion that the effect is of cosmic origin. However, even though Cyg. X-3 lies well inside the region of peak intensity, it does not seem possible to ascribe to it the whole effect, for the implied photon flux appears too large to be reconciled to various gamma-ray measurements of Cyg. X-3. The original data were subjected to a phase-histogram analysis and it as found that only 2.5% of overall recorded data are compatible with a phase-dependent emission from Cyg. X-3. Assuming these events to be gamma rays yields a detected flux of (2.6 + or - 0.3) x 10 to the minus 12th power gamma cm -2s-1 above 5 x 10 to the 14th power eV. Comparing this value with more recent ultra high energy (UHE) photon data from the same source, it is suggested that the available data generally favor a long-term reduction in the Cyg. X-3 inferred luminosity ( 10 to the 13th power eV) by a factor of (1.8 + or - 0.3) per year

Priorities and preferences for school-based mental health services in India: a multi-stakeholder study with adolescents, parents, school staff and mental health providers

Background Schools are important settings for increasing reach and uptake of adolescent mental health interventions. There is limited consensus on the focus and content of school-based mental health services (SBMHSs), particularly in low-resource settings. This study elicited the views of diverse stakeholders in two urban settings in India about their priorities and preferences for SBMHSs. Methods We completed semi-structured interviews and focus group discussions with adolescents (n=191), parents (n=9), teachers (n=78), school counsellors (n=15), clinical psychologists and psychiatrists (n=7). Qualitative data were obtained on prioritized outcomes, preferred content and delivery methods, and indicated barriers. Results All stakeholders indicated the need for and acceptability of SBMHSs. Adolescents prioritized resolution of life problems and preferred practical guidance. Parents and teachers emphasized functional outcomes and preferred to be involved in interventions. This contrasted with adolescents’ preferences for limited involvement from parents and teachers, to maintain confidentiality. Face-to-face counselling was the most acceptable delivery format; self-help was less frequently recommended but was more acceptable when blended with guidance or delivered as digital interventions. Structured sensitization was recommended to ensure adolescent engagement. Providers endorsed a stepped care approach to address different levels of mental health need among adolescents. Conclusion SBMHSs are desired by adolescents and adult stakeholders in this setting where few such services exist. Sensitization activities are required to support implementation. School counsellors have an important role in identifying and treating adolescents with different levels of mental health need, and a suite of interventions are needed to target these needs effectively and efficiently

Periodic gamma-ray emissions from Geminga at or = 10(12) eV

Analysis of data from an atmospheric Cerenkov telescope indicated the periodic emission of gamma rays of energy 10 to the 12th power eV, at 60.25 second period, from 2CG 195+4. The gamma ray flux at 99% confidence level is estimated to be 9.5 x 10 to 12 photons/sq cm/s

Temporal variation in saffron (Crocus sativus L.)

Saffron (Crocus sativus L. : Irridaceae), the world's most expensive spice is unknown in the wild state (Mathew 1982). It is a triploid (2n=3x=24) and reproduces asexually through corms. In India saffron is cultivated in the Kashmir Valley and also at Kishtwar (Jammu and Kashmir), Ranikhet and Chamoli (Uttar Pradesh). The present investigation was undertaken to assess the temporal variation in saffron from four locations (Chrar-Sharief, Sanatnagar, Pampore and Malabagh). Observations on floral characters were recorded from 200 randomly selected flowers at each location during October-November 1988. The characters included fresh flower weight, flower size (perianth area), stigma length, fresh and dry stigma weight and saffron percentage. &nbsp

Effect of spacings and nitrogen levels on herb and oil yield oil concentration and composition in three selections of Cymbopogon jwarancusa (Jones) Schultz

The performance of three selections of Cymbopogon jwarancusa (SL-7822, SL-7869 and SL-7896) was studied under five spacings and two levels of nitrogen. Though herbage and oil yield was higher in 4.01 m' stand density (50 x 50 cm spacing), 1l.l/m' (30 x 30 cm spacing) stand density was preferred as the projected yield per ha was higher in the latter. Increase in nitrogen from 200 to 300 kg/ba did not result in higher herbage and oil concentration in the leaves. The composition of oil was also not affected by spacings or nitrogen levels. &nbsp