Cardiovascular autonomic function tests in healthy and diabetic subjects

Diabetic autonomic neuropathy [DAN] is common chronic complications of diabetes mellitus [DM] that occur in nearly half of diabetic patients. DAN in patients with diabetes is an irreversible complication, but early detection is important because the condition can't be reversed. The present study was undertaken primarily to investigate cardiovascular autonomic functions in normal healthy individuals and patients with diabetes mellitus [type 1 and type 2 diabetes mellitus; T1DM and T2DM], and to determine the relationship between diabetes and extent of autonomic function impairment. Autonomic functions using five standard tests were examined in 40 diabetic patients and 40 age and sex matched controls. The extent of autonomic dysfunction was determined in the patients. All the patients and the controls were subjected to measurement of heart rate [HR] and P-R interval were monitored from lead II of the ECG and BP was measured by electrosphygmomanometry. Significant [p <0.001] increase in resting heart rate in T2DM [112 +/- 10 bpm] than T1DM [65 +/- 12 bpm] associated with significant decrease in HR variation daring deep breathing T2DM [8 +/- 3 bpm] compared to T1DM [18 +/- 5 bpm], significant decrease in HR response to standing in T2DM [0.7 +/- 0.2 bpm] compared to T1DM [1.06 +/- 0.2 bpm], significant decrease in postural changes in SBP in T2DM [-15 +/- 3 mmHg] compared to T1DM [-3 +/- 8 bpm] and significant decrease in DBP response to hand grip inT2DM [6 +/- l mmHg] compared to T1DM [20 +/- 7 mmHg] within 2-5 years of both types of DM. Moreover, no significant difference between T1DM and T2DM in cardiovascular autonomic function tests after 5 years of DM. Autonomic dysfunction was significantly more frequent in type 2 diabetes mellitus [T1DM] compared with type 1 diabetes mellitus [T2DM]. This study showed that autonomic neuropathy is common in diabetic patients, and that it increases in severity with increase in extent of T2DM, and starts after 5 years in T1DM suggesting that diabetes mellitus contributes to these neurological derangements

Age-related changes in carotid vascular responses to noradrenaline and nitric oxide synthase inhibitor

The aim of the present work was to study whether age alters the constrictor responses evoked by the sympathetic transmitter Noradrenaline in the carotid circulation in the rat. Another aim was to test whether age changes the influence of tonically synthetised nitric oxide [NO] on arterial blood pressure [ABP] and on carotid circulation. Further, to investigate the effect of NO synthesis inhibition on carotid vascular responses euoted by noradrenaline in three age groups of rats. In anaesthetised rats aged 4-5, 10-12 and 42-44 weeks [young, mature, middle-aged respectively], carotid blood flow [CBF] and carotid vascular conductance [CVC] were recorded during infusion of noradrenaline [2.5/micro g.kg[-1]], before and after a bolus dose of the nitric oxide synthase inhibitor L-NAME [10mg.kg[-1]]. In mature and middle-aged rats, noradrenaline infusion increased mean ABP to 180mmHg, but only to 150mmHg in young rats. Concomitantly, CVC decreased more in mature and middle-aged, than in young rats: CBF remained constant in young, but decreased in mature and middle-aged rats. NO synthase inhibition produced similar increases in baseline ABP in all groups, but decreased CVC and CBF more in mature and middle-aged rats. Following NO inhibition, noradrenaline infusion increased ABP to similar levels as before in young and mature rats, but to higher levels in middle-aged rats. Further, CVC fell in young and mature, but not in middle-aged rats, in whom CBF increased with ABP.Thus, in young rats there was a weak noradrenaline-evoked pressor response and decrease in CVC. By contrast, in mature and middle-aged rats, noradrenaline evoked a strong pressor response and decrease in CVC. In young and mature rats, NO seems not to limit the noradrenaline-evoked increases in ABP or decreases in CVC. However, by middle age NO limits noradrenaline-evoked pressor response and prevents breakthrough of CBF Autoregulation. The three age groups showed good autoregulatory response of carotid circulation during a pressor response induced by noradrenaline. However, the constrictor responses evoked by noradrenaline is weak in youngs before the age of sexual maturity. On the other hand, by middle-age and well before old age, the constrictor influences of noradrenaline in carotid circulation have begun to weaken. Moreover, by middle age, the dilator influence of NO helps to prevent breakthrough of Autoregulation of CBF at the upper end of the range

Ectopic hormones secretion in cases of copd and cancer lung is it an index for malignant potential?

This work was undertaken to study the level of peptide hormones [ACTH, aldosterone and parathormone] in patients with lung cancer and different stages of COPD since lung cancers are the most common tumour associated with ectopic production of peptide hormones. Peptide production may be better correlated with the state of tumour differentiation than with the tumour mass, but changes in peptide concentration can signale changes in tumour metabolism or malignant potential. Results revealed an increase in the level of parathormone and ACTH while the level of aldosterone was decreased in about 10% of patients of lung cancer. The changes in hormone level were marked in smoker than non smoker which may be due to tobacco metabolites that alter oncogens and tumor suppression genes. The increase in hormones level occur also in cases of COPD and this increase was directly proportional with the stage of COPD and degree of malignancy. SO these cases of COPD with a high level of hormones considered potential for malignant transformation. Also there was an increase in calcium level in most of patients as a consequence of increase in parathormone. So All signs and symptoms of hormononal disturbance or electrolyte imbalance in cases of COPD should be taken with caustion as an alarming sign for malignancy