In vitro studies of HIV-1 infection in thymic lymphocytes: a putative role of the thymus in AIDS pathogenesis

To ascertain whether thymic lymphocytes represent suitable targets for HIV-1 infection, we infected thymic cell suspensions from normal donors with HIV-1 (HTLV-IIIB strain). We found that, in vitro, thymic lymphocytes are readily infected and highly permissive for HIV-1 replication. In addition, immature cells with the CD4+/CD8+ phenotype, most likely the precursors of mature circulating CD4+ and CD8+ lymphocytes, showed a marked susceptibility to viral infection and replication. These findings suggest that thymus infection may play a triggering role in the pathogenesis of AIDS, particularly in pediatric cases, and may partially explain the lack of restoration of peripheral CD4+ lymphocytes killed by HIV-1.

Assessment of captopril and nicardipine effects on chronic occlusive arterial disease of the lower extremity using Doppler ultrasound

The effects of two potent vasodilating drugs, captopril (C) (25 mg tid), nicardipine (N) (20 mg tid), and placebo (P) were evaluated and compared, in 10 men (mean age of sixty-five years) with intermittent claudication from moderate to severe multilevel chronic occlusive arterial disease (COAD) of the lower extremity, by use of the Doppler ultrasonic method, at rest and after Carter's exercise test. All the examined subjects were normotensive, without diabetes or cardiopathy; all have been smokers. The eight-week total protocol consisted of an initial two-week placebo run-in period followed by two active drug phases and a two-week placebo phase, according to a double-blind, randomized, crossover design. At the end of each two-week period, ankle-arm index (AAI) and, following exercise, onset of lower extremity discomfort time (ODT), duration of exercise (ET), decrease of ankle systolic pressure after test (APD), and recovery time (RT) were determined. Moreover, at rest, just after exercise, and after recovery, simultaneous common femoral artery velocity waves were recorded and analyzed by a quantitative approach to detect the peripheral vasomotor adjustments. None of the patients required the withdrawal of the active treatments. Compared with P, C significantly reduced APD and RT, and N reduced RT and AAI; furthermore N caused a significant decrease in ODT, whereas C showed a trend, although not statistically significant, to increase ODT. Neither active therapy modified ET. These results suggest that C and N have different short-term effects on peripheral circulation in COAD. During exercise, C induces hemodynamic improvement in the ischemic lower extremity probably by inhibition of the sympathetic system and consequent reduction in collateral vessel vasoconstriction.

Carotid artery atherosclerotic disease assessed by flow velocity wave form analysis in hemodialyzed normotensive and hypertensive patients

Cerebrovascular accidents, often secondary to severe atherosclerotic disease, are very common in uremic patients on long-term hemodialysis. The aim of the present study is to assess asymptomatic carotid artery atherosclerotic disease (CAAD) in hemodialyzed normotensive and hypertensive patients in comparison with age-matched controls, by the use of Doppler ultrasound flow velocity wave form analysis (FVWFA), recorded from the common carotid artery. This study was performed on 47 subjects divided into four groups: 10 young and 10 middle-aged normals were considered in groups I and II, respectively, 5 young uremic normotensive, 6 young uremic hypertensive and 16 middle-aged uremic normotensive patients in groups III, IV and V, respectively. All the examined patients were nonsmokers, without diabetes or cardiopathy. The five wave form dimensions most capable of separating different degrees of atherosclerotic disease were determined on every common carotid tracing and used in a single best fit discriminant equation; the resultant discriminant score (DS) classified each carotid tracing and consequently every group's range. DS of groups I and III were not different, but significantly higher compared to the other three groups; besides DS was statistically not different in groups II, IV and V. In conclusion, FVWFA did not detect a different degree of CAAD between normotensive dialyzed patients and age-matched normals, whereas the blood pressure pharmacological control did not affect the velocity findings of advanced CAAD in young uremic hypertensive patients.

Asymmetric septal hypertrophy and sympathetic overactivity in normotensive hemodialyzed patients

Sympathetic activity has been evaluated in 23 chronic uremic normotensive patients on long-term hemodialysis. M-mode and bidimensional echocardiographic finding of asymmetric septal hypertrophy (ASH) was shown in seven (30.4%). Sympathetic function was assessed by determining arterial plasma norepinephrine (plasma NE) and epinephrine (plasma E) in supine and upright positions, both before and after dialysis. After dialysis standing caused a significant increase in plasma NE levels in the patients with ASH in comparison to the patients without ASH and the control group. A significant decrease in mean blood pressure (mBP) and a sharp heart rate (HR) increase were detected in the patients without ASH, whereas mBP and HR were unchanged in the patients with ASH. Predialysis serum creatinine and fasting triglycerides were found to be significantly higher in the group with ASH. These results suggest that sympathetic overactivity may play a role in the development of interventricular septum hypertrophy. This increased neurosympathetic responsiveness is probably related to the counteraction of the postural dialysis-induced hypotension.

Asymmetric septal hypertrophy in uremic-normotensive patients on regular hemodialysis. An M-mode and two-dimensional echocardiographic study

We have observed a high incidence (36.4%) of asymmetric septal hypertrophy (ASH), detected with the use of M-mode (MME) and two-dimensional echocardiography (2DE), in normotensive patients with chronic renal failure on maintenance hemodialysis without signs of cardiac diseases. ASH was detected by conventional MME in 11 cases and was confirmed with the use of 2DE in 8 cases showing a diagnostic concordance of 72.7% between the two methods. After dialysis the MME study of the left ventricular (LV) performance showed an evident impairment of cardiac index (CI) due to reduction of LV volume in addition to an abnormality of septal function. The presence of ASH does not impair the percentage of fractional shortening (FS%), the mean circumferential shortening (mean Vcf) and the ejection fraction (EF%), probably because of a compensatory performance of the LV posterior wall. Predialysis serum creatinine and fasting triglycerides have been found significantly higher in the group with ASH. ASH may be considered as a focal and early form of myocardial involvement in uremic patients on regular hemodialytic treatment.

[Relation between asymmetrical hypertrophy of the interventricular septum and plasma levels of catecholamines in normotensive chronic uremic patients undergoing hemodialysis treatment]

Sympathetic-adrenergic activity has been evaluated in 23 chronic uremic, normotensive patients on regular hemodialysis, 7 of which (30.4%) with M-mode and bidimensional echocardiographic finding of asymmetric septal hypertrophy. The sympathetic function has been assessed by measuring arterial plasma norepinephrine and epinephrine levels before and after postural activation, just before and after dialysis. After dialysis, standing caused a significant increase of plasma norepinephrine levels in patients with asymmetric septal hypertrophy in comparison with patients without asymmetric septal hypertrophy and with the control non uremic group. Moreover, a significant decrease in blood pressure and a sharp heart rate increase were noted in the patients without asymmetric septal hypertrophy, whereas mean blood pressure and heart rate were unchanged in the patients with asymmetric septal hypertrophy. These results suggest that increased plasma norepinephrine concentration may have a role in the development of interventricular septal hypertrophy.

Peripheral and central components in the hyperthermic effect of desipramine in reserpinized rats

Pithed rats show a decrease of body temperature which is not affected by reserpine, cocaine or desipramine. Noradrenaline decreases the rate of fall of body temperature and this effect is enhanced by pretreatment with cocaine or desipramine. Reserpine with desipramine or with cocaine also produces a decreased rate of fall of body temperature. But if reserpine is given 18 hr before pithing, desipramine is without effect although noradrenaline and 2,4-dinitrophenol produce a calorigenic response. The hyperthermic effect of desipramine in reserpinized rats is also decreased by spinal transection. Lumbar transection is less effective than cervical transection. It is concluded that the integrity of the central nervous system is required for the development of the hyperthermic effect of desipramine in previously reserpinized rats.

Further effects of imipramine and its desmethyl derivative on the hypothermia induced by reserpine

Imipramine and desipramine injected intracerebrally increase the temperature of fully reserpinised rats. Desipramine is more effective than imipramine in this. The effect of imipramine seems to be independent of the formation of desipramine in the brain. That imipramine, injected intraperitoneally, leads to an accumulation of brain desipramine has been confirmed.