Search PubMed⌕ Search

Biomedical subjects

J Mohan

Publications and source records attributed to J Mohan.

At least 37 records · Page 2Linked to original sources
PubMed1994

Responses evoked in the forearm vasculature on normal human subjects on repetition of mild, indirect cooling.

We have studied responses evoked in the forearm vasculature of normal subjects by mild cooling of the contralateral hand; it was transferred from thermoneutral water at -33 degrees C to water at 16 degrees C for 2 min. Total forearm blood flow was measured by venous occlusion plethysmography, cutaneous red cell flux was monitored with a laser Doppler flowmeter and arterial pressure was recorded by semi-automatic sphygmomanometry. In each of two groups (I and II) of twelve and 15 subjects, mild cooling evoked a rise in mean arterial pressure, but in each group, approximately half (six and eight respectively) showed a decrease in total forearm vascular resistance (FVR) in response to the first cool immersion (dilator group), while the remainder showed an increase in FVR (constrictor group), apart from one of group II who showed no change in FVR. Cutaneous vascular resistance tended to increase in both the dilator and constrictor groups, but this did not reach statistical significance. When cooling was repeated six times in group II, the decrease in FVR (-18% from control) in the dilator group reversed to an increase in FVR (+25%) by the sixth immersion, while the increase in FVR (+55%) in the constrictor group persisted through to the sixth immersion (+23%). We propose that mild cooling evokes a primary reflex vasoconstrictor response in forearm muscles, but that this can be overcome in some subjects by the characteristic muscle vasodilatation of the alerting response which is evoked by novel, or noxious stimuli; the latter is known to habituate on repetition of the stimulus.

Adult↗
PubMed1994

A comparative study in subjects with homozygous sickle cell disease and in normal subjects of responses evoked in forearm vasculature by mild, indirect cooling.

We have studied responses evoked in the forearm vasculature of twelve subjects with homozygous sickle cell disease (SS) and in eight dark-skinned controls of West Indian ancestry (AA) by mild cooling of the contralateral hand in water at 16 degrees C for 2 min; this stimulus was repeated six times at randomized time intervals. Total forearm blood flow was measured by venous occlusion plethysmography, cutaneous red cell flux was monitored by a laser Doppler flowmeter and arterial pressure was recorded by semi-automatic sphygmomanometry. Of the AA subjects, three showed a decrease in total forearm vascular resistance (FVR, of -10%) in response to the first immersion and this reversed to an increase in FVR (+7%) by the sixth immersion. The remaining five showed an increase in FVR (+65%) which persisted until the sixth immersion (26%). By contrast, all SS subjects showed an increase in FVR (+32%) which persisted to the sixth stimulus (+27%). Further, on a scale of discomfort of 0-10, none of the AA subjects rated the cool stimulus higher than 0, whereas SS subjects gave a rating of 7 for the first stimulus which decreased to 5 by the sixth stimulus. Both AA and SS subjects showed an increase in arterial pressure and a tendency towards vasoconstriction in forearm skin. We propose that, as in Caucasian AA subjects, dark-skinned AA subjects showed a primary reflex vasoconstriction in forearm muscle in response to mild, indirect cooling which was overcome in some individuals by muscle vasodilation of the alerting response that is evoked by novel or noxious stimuli.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Coronary heart disease: trends in spatial inequalities and implications for health care planning in England.

The idea of health gain has recently received particular emphasis in health policy in England. One of the areas where there is considerable scope for health gain is in the reduction of mortality due to Coronary Heart Disease. Some reduction in mortality rates due to this cause have already been achieved in England in the 1980s. However, the change in standardised mortality rates varies around the country. A review of studies of geographies of declining CHD mortality shows that such geographical variation is typical of other countries which have recently experienced a reduction in the CHD epidemic. The paper presents the results of an analysis of change in spatial inequality in coronary heart disease mortality among the population aged 35-74 for the 190 District Health Authorities in England over the period 1982-1989. Data were derived from counts of cause-specific deaths and population estimates published by the Office of Population Censuses and Surveys. Various approaches were used to assess the change in spatial disparity which has accompanied the average overall reduction in mortality rates over the study period. The results show that the trends vary between age and sex groups in the population and that, particularly for older people, overall health gain across the country is being achieved at the cost of greater inequality in health between areas. The implications for local health strategies with respect to coronary heart disease reduction are discussed.

Adult↗
PubMed1993

Angiotensin converting enzyme activity in female reproductive tract of domestic fowl (Gallus domesticus) and its interactions with semen.

Presence of angiotensin converting enzyme (ACE, EC 3.4.15.1) in female reproductive tract and its interaction with semen has been investigated in domestic fowl. Higher activity of ACE was detected in homogenates of infundibulum region followed by magnum and relatively low level was noticed in rest of the parts of the oviduct (i.e. isthmus, uterus, uterovaginal-junction and vagina). This decreasing order in ACE activity was, however, reversed when these segments were incubated with semen. ACE in the ovarian follicular wall increased with corresponding increase in the follicle size. Presence of some stimulatory or inhibitory substances for ACE in the oviduct of fowl is suggested.

Animals↗
PubMed1992

Effects of cold shock treatment on angiotensin-converting enzyme activity and on semen characteristics in roosters and bulls.

Angiotensin-converting enzyme (ACE) activity has been determined in the semen of certain avian and mammalian species as well as its release during cold shock. The maximum and minimum levels of this enzyme were found in mammalian spermatozoa and in seminal plasma, respectively. It was found that ACE activity in mammalian spermatozoa was more pronounced than in the seminal plasma, whereas in the avian species a revers pattern was observed. However, there were no significant differences in ACE activity in spermatozoa and seminal plasma between layer and broiler strains of avian species. By contrast, ACE activity in the spermatozoa and seminal plasma of buffalo bulls was significantly higher (P/ 0.01) than in cattle bulls. Cold shock did not significantly alter semen characteristics in avian species, while a significant (P/ 0.01) decrease in sperm live counts and motility as well as a corresponding increase in morphological abnormalities were observed in the spermatozoa of cattle and buffalo bulls due to cold shock.

Journal Article↗
PubMed1992

The influence of prepubertal partial sinistral ovariectomy on the subsequent reproductive function of domestic hens (Gallus domesticus ).

Each of 20 White Leghorn hens of 13 to 14 weeks were subjected to partial sinistral ovariectomy and sham-operations. In half of the hens from each group, the percentage of egg production and clutch size were noted until 50 weeks of age. The growing pattern of normal ovarian follicles was also recorded at 26 weeks of age in a rest half ofthe hens in the two groups. The percentage of egg production and the mean and variance of clutch size did not differ significantly (P / 0.05) between the partially ovariectomized and sham-operated groups. The growing yellow follicles (>8 mm) in the rapidly developing phase in these two groups did not vary, although the smaller follicles (4 to 8 mm in diameter) remained significantly (P / 0.01) more in the shamoperated control group than in the partially ovariectomized group. This observation indicates that smaller follicles (4 to 8 mm) developed in the larger (>8 mm) follicles more efficiently in partially ovariectomized hens than in the sham-operated (control) hens. In a second experiment, one group of hens had all the yellow follicles (>8 mm) removed, while a second group of hens was left untreated. On the 3rd and 6th day post treatment, the hens were examined for the presence of ovarian follicles. No significant (P / 0.05) difference in the growing pattern of subsequent follicles (2 to 4 or 4 to 8 mm) was detected due to treatment. These data demonstrate that the mechanisms that regulate follicular growth and atresia are adjust to maintain normal ovulation following partial ovariectomy.

Journal Article↗
PubMed1992

Effects of cadmium salt on phosphomonoesterases activity and fertilizing ability of fowl spermatozoa.

Daily administration of cadmium salt for 25 days (2.5 mg per Kg body weight) in the male domestic fowl caused the end of treatment period. An increased incidences of concentration. Fertility dropped to zero at the end of the treatment period. Activity of acid and alkaline phosphomonoesterases were also drastically reduced by the end of treatment period. An increased incidences of morphological abnormalities of spermatozoa were noticed in the treated birds. After 46 days cessation of the treatment, full recovery of the above measures was found. These alterations suggest the reversible type of effect of cadmium chloride on the spermatozoa of male domestic fowl.

Animals↗
PubMed1991

Histamine in egg yolk: heat resistance and relation to production status.

1. The presence of histamine in egg yolk, its losses during storage, incubation and heating, and its relationship to cage density stress and the egg production status of hens are described. 2. A significant (P less than 0.05) reduction in the histamine concentration of egg yolk was noted after incubating or heating egg yolks or on storage eggs. 3. Histamine concentration was greater in the yolks of high egg producing hens. 4. The concentrations of histamine in egg yolks did not change significantly (P less than 0.05) on keeping the hens individually in a cage, pairing them in the same size cage or after separating them again to individual cages.

Animals↗
PubMed1990

Variation in angiotensin-converting enzyme activity in the testes of prepubertal, pubertal and adult cockerels.

The variation in the level of angiotensin-converting enzyme in the testes of prepubertal, pubertal and adult cockerels were investigated. Maximum levels of angiotensin-converting enzyme were observed at 8 wk of age, followed by a progressive decrease (P/0.01) until 14 wk of age. After this stage, however, a rapid growth rate of the testes and comb was noted. The concentration of angiotensin-converting enzyme in pubertal and adult birds remained at a significantly lower level than in the prepubertal birds. The level of activity of this enzyme was significantly but negatively correlated with age and with the weights of the testes and comb. The high level of this enzyme found in prepubertal cockerels suggests it may be more highly involved in the early rather than later stages of spermatogenesis.

Journal Article↗
PubMed1990

Effects of cyproterone acetate and testosterone treatments on some physical parameters, angiotensin converting enzyme activity and fertilizing ability of spermatozoa of domestic cocks (Gallus domesticus).

Healthy adult cocks were administered through the intramuscular route with 1 or 15 mg cyproterone acetate (CyA)/kg b. wt. or testosterone at the rate of 1.5 mg/kg b. wt. daily for a period of 25 days. High doses of CyA and testosterone caused severe suppression (P less than 0.01) of semen volume, sperm concentration, sperm motility and angiotensin converting enzyme activity (ACE EC 3.4.15.1). Fertilizing ability of spermatozoa was also reduced drastically at the end of treatment period. No loss of sexual behaviour was observed in treated birds as compared to controls. Recovery in all parameters from deleterious effects of these drugs was rapid after cessation of treatment. Lower doses of CyA did not affect the parameters of semen. The results are discussed in relation to the possible mechanism of action of CyA and testosterone.

Animals↗
PubMed1989

Studies on antifertility effects of gossypol acetic acid in domestic cocks.

Daily oral administration of gossypol acetic acid (40 mg/kg body weight daily) resulted in a gradual decrease in the semen volume and sperm concentration. Fertility dropped to zero at the end of the treatment period. Activities of acrosin, hyaluronidase and angiotensin converting enzyme were also drastically decreased by the end of the treatment period. A loss of appetite, loss of body weight and morphological abnormalities in spermatozoa were noticed in the treated cocks. At 4 weeks after cessation of the treatment, full recovery of the above measures was recorded. Healthy chicks were hatched and were observed for several months.

Acrosin↗
PubMed1986

Private medical care and the British conservative government: what price independence?

This paper discusses issues raised by the uneven expansion of private health care in Britain in recent years. The problems being experienced by the industry have exposed divisions in the private health care industry and have provoked criticisms of the Government and requests for a greater degree of state support for, and regulation of, the industry. The paper therefore examines the scope for changes of government policy to facilitate further expansion. It argues that few of the alternatives are either technically adequate, in terms of solving the private sector's problems, or politically feasible, in the sense of being electorally justifiable. It concludes that policies to further private sector expansion could be implemented only at the cost of the private sector's independence, or at the expense of the Government's commitment to the NHS.

Economic Competition↗
PubMed1985

Restructuring health care: the social geography of public and private health care under the British Conservative Government.

The 1979 election of the Conservative Government in Britain was not followed by the demolition of the welfare state. However, a variety of policy initiatives were introduced both to restructure National Health Service (NHS) expenditure, and to facilitate private provision of health services. This article considers the effects of such policies on the existing and future distribution of health care resources. A historical introduction discusses the main thrusts of conservative welfare policy. This is followed by an examination of the current financial situation of NHS authorities, at the regional and sub-regional scales; the political response to the 1983 manpower reductions is also considered. Events in the NHS are then contrasted with the deregulation of the private sector. The emergence and distribution of commercial acute hospitals are examined, as are other initiatives designed to transfer some of the financial burden of welfare provision away from the state. A concluding section compares and contrasts these developments and considers prospects for the future form of health care provision in Britain.

Catchment Area, Health↗