Enfermedad de Castleman multicéntrica en sida. Su relación con el VHH-8 o virus herpes asociado al sarcoma de Kaposi. Estudio de dos casos

Castleman disease is considered a reactive lymphadenopathic picture with two clinical forms: one localized, frequent in immunocompetent patients and another multicenter one that is more characteristic in immunodepressed patients. Two cases of Castleman disease multicenter in HIV positive patients with Kaposi's sarcoma are presented. Both patients have multiple adenopathies, hepatomegaly and symptoms B on diagnosis. One of them had a favorable response to chemotherapy treatment and another died. A review of the concept of multicenter Castleman disease and its pathogenic relationship to human herpes virus 8 (HHV-8) is done.

A randomized controlled trial investigating the efficacy and safety of switching from a protease inhibitor to nevirapine in patients with undetectable viral load

OBJECTIVE

To assess the antiviral efficacy and safety of switching from a protease inhibitor (PI) to nevirapine in patients with long-term HIV-1 RNA suppression on PI-containing regimens, and to assess its influence in the adherence to treatment.

METHODS

In an open-label multicentre study, 160 HIV-infected patients with undetectable viral load for at least 6 months on a PI-containing regimen were randomized to either continue with their PI regimen (n=79) or replace PI with nevirapine (n=81). Clinical assessment included plasma HIV-1 RNA, blood chemistry, haematology, lymphocyte counts and adverse events reports. Adherence to treatment and lipodystrophy syndrome were assessed by patient self-reporting.

RESULTS

Treatment efficacy was equivalent in the two arms, for patients with viral loads either above or below 100 000 HIV-1 RNA copies/mL. The increase in CD4 cell count was significant in both arms (P<0.00001) but the average CD4 cell count at 48 weeks was slightly higher in the nevirapine arm (596 vs. 569; P=0.1588). The number of patients with severe hypertriglyceridaemia (>400 mg/dL) after 48 weeks of treatment decreased in the nevirapine arm (from 11 to six), but increased in the PI arm (from four to 11) and led to treatment discontinuation in two patients. Lipodystrophy changes increased in 15% of patients in the PI arm but decreased in 4% of patients in the nevirapine arm. Finally, although adherence was similar in the two arms, patients reported that it required significantly less effort to stay on treatment in the nevirapine arm. Conclusions The results indicate that switching from PI to nevirapine is as effective as continuing with PI for maintaining viral control, even in patients with baseline viral load above 100,000 copies/mL. In addition, reductions in hypertriglyceridaemia and lipodystrophy and in the effort required to stay on treatment were observed.

Vasorelaxant effect of new neo-clerodane diterpenoids isolated from Croton schiedeanus

The vasorelaxant effect of two new neo-clerodane diterpenoids, (12R)-12-hydroxycascarillone and 5beta-hydroxy-cis-dehydrocrotonin, in addition to the known cis-dehydrocrotonin and trans-dehydrocrotonin, all them previously isolated by us from Croton schiedeanus Schlecht, was studied in isolated aorta rings contracted by high K+ (80 mM) or phenylephrine (1 microM). According to their IC50 values to KCl induced contraction, the potency order was (12R)-12-hydroxycascarillone > cis-dehydrocrotonin > 5beta-hydroxy-cis-dehydrocrotonin > trans-dehydrocrotonin (0.3, 1.5, 96 and >100 mM, respectively). The possible cooperativity between diterpenoid compounds and the predominant flavonoid (ayanin) was studied. The vasorelaxant activity of cis-dehydrocrotonin and ayanin was increased when both compounds were incorporated simultaneously to the aortic rings precontracted with phenylephrine. These results suggest that Croton schiedeanus induces its effects via the synergistic actions of several vasodilator substances, among which neo-clerodane diterpenoids play an important role.

Quercetin 3,7-dimethyl ether: a vasorelaxant flavonoid isolated from Croton schiedeanus Schlecht

The vasorelaxant profile of quercetin 3,7-dimethyl ether, a flavonoid isolated from Croton schiedeanus Schlecht (Euphorbiaceae), was assessed in aortic rings isolated from Wistar rats. To gain insight into its structure-activity relationship, we compared this substance with quercetin 3,4',7-trimethyl ether (ayanin), another flavonoid isolated from this plant, quercetin 3,3',4',7-tetramethyl ether, a flavonoid synthesized by us, and quercetin. In addition we examined the interaction of quercetin 3,7-dimethyl ether with the nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) pathway. According to their pEC50 values (concentration producing a 50% inhibition of the maximal contractile response) to phenylephrine-induced precontraction in rat isolated aorta, the potency order was quercetin 3,7-dimethyl ether > quercetin > quercetin 3,4',7-trimethyl ether > quercetin 3,3',4',7-tetramethyl ether (4.70+/-0.18; 3.96+/-0.07; 3.64+/-0.02; 3.11+/-0.16). The relaxant effect of quercetin 3,7-dimethyl ether was significantly decreased by the removal of endothelium as well as by methylene blue, an inhibitor of guanylyl cyclase, and by N(G)-nitro-L-arginine methyl ester hydrochloride (L-NAME), an NO-synthase inhibitor. Therefore, quercetin 3,7-dimethyl ether has a NO/cGMP pathway-related profile, with increased vasorelaxant activity due to hydroxylation at positions 3 and 4 of the B ring. In addition, methylation at positions 3 and 7 with respect to quercetin of the C and A rings, respectively, seems to further enhance the vasorelaxant activity of quercetin 3,7-dimethyl ether.

Inhibitory effect of N(G)-nitro-L-arginine methyl ester on the anti-adrenergic response elicited by ayanin in the pithed rat

In this study we evaluated the anti-adrenergic response elicited by ayanin, a flavonoid compound isolated from Croton schiedeanus Schlecht, in the pithed rat, and the inhibitory effect of NO synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME), and its acute toxicity profile in mice. In pithed rats ayanin (5 - 50 mg/kg i. v.) caused a dose-dependent decrease in the pressor and chronotropic responses induced by intravenous noradrenaline administration (0.25 microg/kg). This anti-adrenergic response was completely abolished by prior treatment with L-NAME (10 mg/kg i.v ) and the inhibitory effect of L-NAME was reversed after intravenous administration of L-arginine (100 mg/kg, i. v.). No lethal or major toxic effects were observed in mice receiving i. p. administration of ayanin up to a dose of 500 mg/kg. Our findings confirm that ayanin exerts protective cardiovascular effects against the increase in blood pressure and heart rate mainly through a mechanism that depends on the NO/cyclic guanosine monophosphate (cGMP) pathway without acute toxic effects. These results suggest that extracts of Croton schiedeanus, the native south American plant from which ayanin was isolated, might be beneficial in cardiovascular disease.

Assessment of the antihypertensive and vasodilator effects of ethanolic extracts of some Colombian medicinal plants

The antihypertensive and vasodilator effects of ethanolic extracts prepared from Calea glomerata Klatt, Croton schiedeanus Schlecht, Curatella americana L., Lippia alba (Mill)n N.E.Br. and Lupinus amandus, which are medicinal plants used in Colombian folk medicine for the treatment of hypertension, were assayed both in SHR and Wistar rats and in rat isolated aortic rings. At a dose of 20 mg/kg, intravenous bolus administration of the ethanolic extracts, from C. schiedeanus, C. americana and L. amandus showed significant antihypertensive activity in SHR, C. schiedeanus being the most active. C. schiedeanus elicited dose-dependent decreases in mean arterial pressure and heart rate (5-100 mg/kg, i.v.) in SHR but 200 mg/kg administered orally did not show any significant effects, even after 3 h of observation. In intact rat aortic rings, ethanolic extracts from C. schiedeanus and Calea glomerata relaxed the contractions induced by KCl (80 mM) and phenylephrine (10(-6) M) in a concentration-dependent manner (10(-6)-3x10(-4) g/ml), with IC(50) of 6.5x10(-5) (7.3-5.8) g/ml and 7.1x10(-5) (7.9-6.4) g/ml, respectively. Bioguided phytochemical fractionation of the ethanolic extract from C. schiedeanus was started. More than one active principle seems to be present, flavonoids and terpenoids compounds were detected.

Antihypertensive and vasorelaxant effects of aqueous extract from Croton schiedeanus Schlecht in rats

Antihypertensive and vasorelaxant effects of treatment with the aqueous extract of Croton schiedeanus Schlecht (AECS) were investigated in anaesthetized spontaneously hypertensive rats (SHR). Intravenous bolus injections of AECS (5-100 mg/kg) elicited dose-dependent decreases in mean arterial pressure (MAP) and heart rate (HR). Additionally, AECS (10(-6)-3x10(-3)g/ml) completely relaxed the contractions induced by high K(+) concentrations in intact rat aortic rings in a concentration-dependent manner.

Hyperkalemia in patients infected with the human immunodeficiency virus: involvement of a systemic mechanism

BACKGROUND

The appearance of hyperkalemia has been described in human immunodeficiency virus (HIV)-positive patients treated with drugs with amiloride-like properties. Recent in vitro data suggest that individuals infected with HIV have alterations in transcellular K+ transport.

METHODS

With the objective of examining the presence of alterations in transmembrane K+ equilibrium in HIV-positive patients, we designed a prospective, interventional study involving 10 HIV-positive individuals and 10 healthy controls, all with normal renal function. An infusion of L-arginine (6%, intravenously, in four 30-min periods at 50, 100, 200, and 300 ml/hr) was administered, and plasma and urine electrolytes, creatinine, pH and osmolality, total and fractional sodium and potassium excretion, transtubular potassium gradient, plasma insulin, renin, aldosterone, and cortisol were measured.

RESULTS

A primary disturbance consisting of a significant rise in plasma [K+] induced by L-arginine was detected in only the HIV patients but not in the controls (P < 0.001 between groups). A K+ redistribution origin of the hyperkalemia was supported by its rapid development (within 60 min) and the lack of significant differences between HIV-positive individuals and controls in the amount of K+ excreted in the urine. The fact that the HIV-positive individuals had an inhibited aldosterone response to the increase in plasma K+ suggested a putative mechanism for the deranged K+ response.

CONCLUSIONS

These results reveal that HIV-infected individuals have a significant abnormality in systemic K+ equilibrium. This abnormality, which leads to the development of hyperkalemia after the L-arginine challenge, may be related, in part, to a failure in the aldosterone response to hyperkalemia. These results provide a new basis for understanding the pathogenesis of hyperkalemia in HIV individuals, and demonstrate that the risk of HIV-associated hyperkalemia exists even in the absence of amiloride-mimicking drugs or overt hyporeninemic hypoaldosteronism.

Immune complexes from HIV-1+ patients contain infectious virus able to infect normal lymphocytes

It has been suggested that circulating immune complexes containing HIV-1 could be involved in enhancement of the infection through Fc receptors. To test this hypothesis, immune complexes precipitated from the sera of 25 HIV-1-seropositive individuals, at different stages of the disease, were assayed for the presence of infectious virus. When added to phytohemagglutinin-activated peripheral blood lymphocytes, seven of 25 complexes were able to sustain a productive infection. This was demonstrated by release of HIV-p24 antigens in the supernatant of activated but not resting peripheral blood lymphocytes after several days of culture. Moreover, peripheral blood lymphocytes cultured with complexes from HIV-1+ patients but not from control subject, contained integrated HIV-1 provirus in their DNA. These results demonstrated the presence of infectious virus in immune complexes from HIV-1+ patients.

Acute renal failure due to sulphadiazine crystalluria in AIDS patients

We report two AIDS patients who developed acute renal failure while receiving sulphadiazine for cerebral toxoplasmosis. Renal ultrasound revealed diffuse bilateral echogenic shadowing material. 'Sheaves of wheat' crystals, typical of sulphadiazine crystalluria, were present in the urine. One patient required a percutaneous nephrostomy. Hydration and urine alkalinisation resulted in rapid improvement of renal function and ultrasonographic findings. Sulphadiazine-induced crystalluria and acute renal failure is increasingly frequent. Awareness of its existence may lead to prevention and early conservative treatment.

Cutaneous tuberculosis: a clinical, histopathologic, and bacteriologic study

BACKGROUND

In recent years cutaneous infections with Mycobacterium tuberculosis with an atypical clinical appearance have become more common because of the increasing number of immunocompromised patients.

OBJECTIVE

We report the clinical, histopathologic, and bacteriologic data of 11 patients with several forms of cutaneous tuberculosis seen during the past 14 years.

METHODS

Patients from whom M. tuberculosis was isolated from culture of skin biopsy specimens, sinus drainage, or material aspirated from cutaneous abscesses were included. In all but two patients a biopsy specimen was obtained for histopathologic study. All but one patient received combined antituberculous therapy.

RESULTS

The clinical diagnoses were scrofuloderma (four cases), cutaneous miliary tuberculosis (two), lupus vulgaris (two), tuberculous gumma (two), and one unclassified. All but three patients had evidence of either previous or simultaneous tuberculous foci other than in the skin. Histopathologic findings varied according to the type of cutaneous tuberculosis.

CONCLUSION

In some patients with cutaneous tuberculosis, lesions are atypical in appearance because of immunodeficiency. Culture for M. tuberculosis should be performed in all suspected cases, even in those in whom special stains for acid-fast bacilli are negative.

[Nocardiosis: clinical observations apropos of 9 cases]

We have retrospectively analyzed 9 cases of nocardiosis that were studied in our hospital over the past 10 years. 66% of the patients had an associated disease and half of them were on steroid treatment. The clinical manifestations of the infection were pulmonary and cutaneous and in 44% of cases, it disseminated to the central nervous system. The diagnosis was made in all cases isolating the microorganism from pulmonary secretions, puss, spinal fluid and blood. Nocardia asteroides was isolated in 8 cases, and nocardia caviae in one case. There was a 55% mortality rate. The different clinical presentation and evolution are reviewed, as well as prognostic factors and antimicrobial treatment of nocardiosis.