Cytokine analysis at the single cell level and lymphoproliferative responses to mycobacterial antigens in HIV-1 patients with successful virologic response to potent antiretrovirals

Immunologic parameters, known to be grossly abnormal in HIV-1-infected subjects, were analyzed in 22 patients with sustained viral load suppression (<200 copies/ml) following long-term highly active antiretroviral therapy (HAART). Responses were compared with those from 18 HIV-seronegative healthy controls. Persistent phenotypic alterations in patients' blood mononuclear cells were minimal, though the percentages of lymphocytes that could be activated to produce interleukin-2 (IL-2) remained severely depressed. Using lymphoproliferative assays, a striking deficit in the capacity of patients to respond to the common mycobacterial antigens and particularly to recombinant heat-shock proteins paralleled the absence of responses to virus p24 antigen. In view of the important immunoregulatory role of stress proteins, these findings reveal profound functional deficiencies and persistent immune dysregulation in HIV-1 patients, despite successful HAART and a considerable recovery of CD4+ lymphocyte numbers. Rational immunotherapeutic approaches should be aimed to correct the characterized immune abnormalities.

Interleukin-16 (IL-16) inhibits human immunodeficiency virus replication in cells from infected subjects, and serum IL-16 levels drop with disease progression

The role of recombinant interleukin-16 (rIL-16) in regulating human immunodeficiency virus type 1 (HIV-1) replication in endogenously infected cells has been investigated. Cultures of CD8 cell-depleted mitogen-activated lymphocytes from 22 of 26 HIV-1-infected subjects presented variable levels of secreted p24 antigen. The presence of rIL-16 throughout the 14-day culture period dramatically inhibited p24 release into the culture supernatants. This effect was found to be mediated through inhibition of viral transcription but to be independent of the induced levels of other cytokines or chemokines known to regulate viral replication. Analysis of serum samples from HIV-1-infected subjects over a period of 8 years showed maintained or even increased IL-16 levels during the whole asymptomatic phase and a significant drop on progression to disease. These results strongly support a potential therapeutic value of rIL-16 in HIV-1 infection and the use of serum IL-16 levels to monitor disease progression.

A study of strontium binding to albumins, by a chromatographic method involving atomic emission spectrometric detection

A chromatographic method involving ICP-AES (inductively coupled plasma atomic emission spectrometry) detection has been successfully applied for the study of strontium-protein complexes. The chromatographic step involves the use of gel filtration-a large-zone Hummel and Dreyer method-which allows to dissociate the bound metallic ions and the free ones. This step is followed by an ICP-AES analysis of fractions collected throughout the chromatographic experiment: the concentration of ionic metallic species in solution can therefore be calculated. Two proteins have been tested: bovine serum albumin, which showed only weak interactions with Sr2+ ions, and bovine alpha-lactalbumin: this protein, well-known for its calcium binding capacity, proved to interact strongly with strontium. The influence of various parameters on the formation of strontium-lactalbumin complexes were determined, namely temperature, pH. Competition experiments between Sr2+ ions and, respectively Na+ and Ca2+ ions were also performed, by varying ionic strength of the medium, and by using both apo and native forms of bovine alpha-lactalbumin.

Genital mycoplasmas in patients with acquired immunodeficiency syndrome

To determine whether Mycoplasma fermentans. Mycoplasma genitalium and Mycoplasma penetrans were present in the genitourinary tract of HIV infected patients in Nancy, France, we have used culture and polymerase chain reactions on urine from 54 HIV-infected patients. Both techniques failed to reveal these bacteria. This renders their presence very unlikely in our population.

Effect of locally applied drugs on the endolymphatic sac potential

In Ménière's disease, an inner ear disorder related to an endolymphatic hydrops, an alteration of the functioning of the endolymphatic sac has been proposed. The endolymphatic sac is assumed to be involved in the secretion/resorption of endolymph. The epithelial transport systems have been indirectly studied by the recording of the endolymphatic sac transepithelial potential (ESP) in control conditions and after the local injection of drugs such as diuretics that have been proposed in the treatment of Ménière's disease. The ESP was recorded, in vivo, in guinea pigs up to 150 minutes after the perisaccular injection of 5 microL of a 150 mmol/L (mM) NaCl solution containing various drugs known to inhibit ionic transport systems. The initial ESP was +8.4+/-0.3 mV (mean +/- SEM, n = 78). The basolateral injection of 5 microL of 150 mM NaCl induced an ESP decrease of 64%+/-6.0% (n = 12), 5 minutes after the end of the injection. Then ESP increased, returning to its initial value at 60 minutes and surpassing it at 120 minutes. Diuretics such as acetazolamide (10[-3] mol/L [M]), an inhibitor of carbonic anhydrase, and amiloride (10[-4] M), an inhibitor of Na channel or Na/H exchanger, decreased the ESP recovery. At variance, bumetanide (10[-6] M, 10[-4] M), the Na-K-Cl cotransport inhibitor, and chlorothiazide (10[-4] M), a Na-Cl cotransporter inhibitor, failed to alter the ESP as compared with the control group. Ouabain (10[-3] M), the Na+,K+-adenosine triphosphatase (ATPase) inhibitor, prevented the ESP recovery otherwise observed 60 minutes after the NaCl injection. Bafilomycin A1, the inhibitor of the vacuolar-type H+-ATPase, prevented the recovery of the ESP with a log-dose/effect (10[-5] M, 10[-6] M, 10[-8] M). Disulfonic acid stilbene (DIDS) (10[-4] M), an inhibitor of transporters involving HCO3-, also prevented the ESP recovery. These results suggest that the genesis of the ESP was highly dependent on acid-base transport systems including carbonic anhydrase, a vacuolar-type H+-ATPase, and an anionic transport system blocked by DIDS. Further studies are needed to confirm the alteration of the acid-base balance in this epithelium and its possible involvement in the pathogenesis of Ménière's disease.

Enterocytozoon bieneusi multiorgan microsporidiosis in a HIV-infected patient

Multiorgan microsporidiosis due to Enterocytozoon bieneusi was diagnosed in an HIV-infected patient. The parasite was found and identified as E. bieneusi by transmission electron microscopy in stools, duodenal biopsy, nasal discharge and sputum. No clinical improvement or parasite eradication was obtained after albendazole therapy, but the patient remained alive 9 months after diagnosis.

Chromatographic method involving inductively coupled plasma atomic emission spectrometric detection for the study of metal-protein complexes

A chromatographic method has been used to study metal ion-protein complexes. It involves successively a gel filtration technique to separate and distinguish the complexed from the free metallic ions, and a spectrometric technique, inductively coupled plasma atomic emission spectrometry (ICP-AES), which allows us to calculate accurately the concentration of ionic metallic species in solution. In the chromatographic step, we applied a large-zone Hummel and Dreyer method. Thus, fractions can be collected throughout the chromatographic experiment and their metal concentration measured by ICP-AES, at constant and known protein concentration. This method has been tested on the copper complex of bovine serum albumin. Results of our study are in good agreement with previous studies on this complex.

Legionella jordanis pneumonia unresponsive to fluoroquinolones in a non-immunocompromised host

Legionella jordanis has seldom been reported as a cause of infection in humans. We describe a case of pneumonia due to L. jordanis that occurred in a non-immunocompromised 74-year-old patient and failed to respond to a combination of ceftriaxone and ofloxacin. Cure was achieved only after an erythromycin-rifampin combination was started.

[Malnutrition and HIV infection]

The wasting syndrome is well known in HIV infected patients. Predominant free fatty mass deletion is achieved. The weight loss results from decrease of food intake, from gut disorders due to HIV or opportunistic infections. Metabolic disorders are reported too. Breakdown of carbohydrates and proteins presents energy source. Raised free fatty acid turn over and hypertriglyceridemia are reported. Polyunsatured fatty acid level is raised inducing free radicals increase. Free radicals delete immune functions (apoptosis). Vitamin and trace element decrease worsen negative effects of free radicals.

Locally formed 5-hydroxytryptamine stimulates phosphate transport in cultured opossum kidney cells and in rat kidney

Renal proximal tubular cells have been shown to express aromatic L-amino acid decarboxylase (L-AAAD), which converts L-dopa into dopamine and 5-hydroxytryptophan [(OH)Trp] into 5-hydroxytryptamine (5-HT; serotonin). Because 5-HT receptors have been demonstrated in proximal cells, we hypothesized that 5-HT may act as an autocrine/paracrine modulator of proximal transport. We evaluated this possibility in opossum kidney (OK) cells, a renal epithelial cell line with a proximal phenotype expressing 5-HT1B receptors, and in intact anaesthetized rats. 5-HT synthesis by OK cells increased with incubation time and (OH)Trp concentration, and was abolished by benserazide, an L-AAAD inhibitor. 5-HT reversed parathyroid hormone (PTH)-induced cAMP accumulation in a pertussis toxin-sensitive manner and reduced the PTH inhibition of P(i) uptake without affecting the NaP(i)-4 mRNA level. The effects of 5-HT on cAMP generation and Na-P(i) co-transport were reproduced by (OH)Trp, except in the presence of benserazide, and by L-propranolol and dihydroergotamine, two 5-HT1B receptor agonists. In rats, (OH)Trp and dihydroergotamine decreased fractional P(i) excretion. Benserazide abolished the effect of (OH)Trp but not that of dihydroergotamine.

IN CONCLUSION

(i) locally generated 5-HT blunts the inhibitory effect of PTH on Na-P(i) co-transport in OK cells; (ii) endogenous 5-HT decreases P(i) excretion in rats; and (iii) 5-HT is a paracrine modulator involved in the physiological regulation of renal P(i) transport.

Rat lung alveolar type II cell line maintains sodium transport characteristics of primary culture

Culture of primary alveolar type II cells has been widely used to investigate the Na+ transport characteristics of alveolar epithelium. However, this model was restricted by early morphological and physiological dedifferentiation in culture. Recently, a cell line has been obtained by transfection of neonatal type II cells with the simian virus SV40 large T antigen gene (SV40-T2). SV40-T2 cells have retained proliferative characteristics of the primary type II cells (Clement et al., 1991, Exp. Cell Res., 196:198-205.) In the present study, we have characterized Na+ transport pathways in SV40-T2 cells. SV40-T2 cells retained most cardinal properties of the original alveolar epithelial cells. Na+ entry occurred, as in primary cultures, through both Na(+)-cotransporters and amiloride-sensitive Na+ channels. SV40-T2 cells expressed Na(+)-phosphate. Na(+)-amino acid and Na(+)-K(+)-Cl cotransports which are quantitatively similar to that of primary cultures. The existence of amiloride-sensitive Na+ channels was supported by molecular and functional data. SV40-T2 expressed the cloned alpha- and gamma-mRNAs for the rat epithelial Na+ channel (rENaC), whereas beta subunit was not detected, and 22Na+ influx was significantly inhibited by 10 microM amiloride. Na+, which enters SV40-T2 cells, is extruded through a Na+, K(+)-ATPase: mRNA for alpha 1 and beta 1 isoforms of Na+, K(+)-ATPase were present and Na+, K(+)-ATPase activity was evidenced either on intact cells by the presence of a ouabain-sensitive component of 86Rb+ influx or on cell homogenates by the measurement of ouabain-inhibitable ATP hydrolysis. These results indicate that SV40-T2 cell line displays most of the Na+ transport characteristics of well-differentiated primary cells in the first days of culture. We conclude that the SV40-T2 cell line provides a model of differentiated alveolar type II cells and may be a powerful tool to study, in vitro, the modulation of Na+ transport in pathophysiological conditions.

Effect of glycerol on electrochemical composition of endolymph and perilymph in the rat

Glycerol (2 g/kg body weight), or 0.15 M NaCl for control animals, was administered to rats by i.v. injection. The dose was chosen in order to obtain an osmolarity increase in plasma of about 15 mosm/l 1 h after the glycerol administration, an increase which is similar to that observed in the human glycerol dehydration test. Endolymph and perilymph were sampled from the basal turn of the cochlea; cerebrospinal fluid (CSF) was sampled from cisterna magna. Plasma osmolarity, endocochlear potential, Na and K concentrations in endolymph, perilymph and CSF were determined 1 and 2 h after the glycerol injection. Compared with control animals, glycerol induced an increase in Na and K concentration in perilymph and endolymph, respectively, 1 and 2 h after the glycerol injection. No modification of the endocochlear potential was observed. These results are compatible with an increase in inner ear fluids osmolarity induced by glycerol.

Inhibition of Na-K-ATPase activity after prolonged hypoxia in an alveolar epithelial cell line

Exposure to alveolar hypoxia may induce acute pulmonary edema. Because the vectorial sodium transport by alveolar epithelium represents an important mechanism for alveolar edema clearance, we examined whether hypoxia affects Na-K-ATPase activity in cultured SV40-transformed rat alveolar type II cells (SV40 ATII cells). Hypoxic exposures (O or 5% O2 for at least 12 h) induced a time- and O2 concentration-dependent decrease in ouabain-sensitive rubidium (osRb) influx. Neither the sensitivity of Rb influx to ouabain nor the maximum velocity of the enzyme measured on crude cell homogenates was affected by hypoxia. The osRb influx decrease was independent of hypoxia-induced ATP depletion. Na-K-ATPase inhibition was most likely related to impaired calcium homeostasis, because 1) calcium influx was increased in hypoxic cells, 2) hypoxia-induced osRb influx decrease was completely prevented by nifedipine (10-5 M), and 3) osRb influx decreased in normoxic cells incubated with ionomycin (10-6 M, 15 min). Furthermore, hypoxia-induced Na-K-ATPase impairment might be due, at least in part, to the endogenous release by hypoxic cells of a lipidic factor in extracellular medium, because incubation of normoxic cells with hypoxic cells conditioned medium (CM), or with the lipidic subphase from hypoxic cells CM, also induced a partial decrease in osRb influx. This decrease was associated with increased calcium influx into normoxic cells and was suppressed either by the removal of external calcium or by nifedipine, suggesting that the lipidic factor exerted its inhibitory action on Na-K-ATPase via an enhancement of calcium entry. These results indicate that prolonged hypoxic exposure impairs Na-K-ATPase activity in SV40 ATII cells and may therefore decrease the vectorial sodium transport by alveolar epithelium.

[Prognostic factors of Pneumocystis carinii pneumonia in AIDS]

OBJECTIVES

Identify prognosis factors in Pneumocystis carinii pneumonia at diagnosis and construct a model to predict mortality according to these prognosis factors.

METHODS

Seventy-seven consecutive cases of proven AIDS-related Pneumocystis carinii pneumonia (67 men, 10 women, mean age 37.2 years) were reviewed to determine the most accurate initial prognostic factors and estimate an individual prediction of death. A stepwise logistic regression analysis was performed. Three kinds of data were entered into the logistic model: historical data, clinical and laboratory data obtained within the first 24 hours of diagnosis, and specific data related to chest X-ray and bronchoalveolar lavage results.

RESULTS

The sum of arterial partial pressure of oxygen and carbon dioxide (PaO2 + PaCO2) and serum albumin level best predicted a fatal outcome in multivariate analysis.

CONCLUSION

The logistic equation provided by the model might be used to accurately and quickly identify the patients with severe Pneumocystis carinii pneumonia who might benefit from supportive intensive care.

Inhibition of ecto-5'-nucleotidase by nitric oxide donors. Implications in renal epithelial cells

We evaluated, in renal epithelial cells with a proximal tubule phenotype, the effect of nitric oxide (NO) on ecto-5 -nucleotidase (5'-N U), the underlying mechanism and its functional consequence. Sodium nitroprusside (SNP, 1-1000 microM), a NO donor, inhibited 5'-NU activity in a time- and concentration-dependent manner. Consequently, NO blunted the inhibition by extracellular cyclic AMP (cAMP, 10-1000 microM) of sodium-phosphate cotransport, a pathway which involves degradation of adenosine monophosphate (AMP) by 5'-NU. SNP-induced inhibition of 5'-NU was not mediated by cyclic GMP, since it was not mimicked by atrial natriuretic peptide, and was reproduced by isosorbide dinitrate and sodium nitrate, two NO donors. SNP and genuine NO decreased the activity of 5'-NU in renal homogenates, and the effect of SNP was potentiated by dithiothreitol and glutathione, but not by nicotinamide adenine dinucleotide. In vivo in rats, kidney ischemia/reperfusion, which activates inducible NO-synthase, inhibited renal 5'-NU. This inhibition was prevented by Nomega-nitro-L-arginine methyl ester, a NO-synthase inhibitor. These results indicate that: (i) NO-related activity inhibited the activity of an ecto-enzyme, 5'-NU, most likely through S-nitrosylation of the enzyme; (ii) inhibition of 5'-NU activity by NOx, which can occur in vivo under pathophysiological conditions, affected the extent to which extracellular cAMP inhibited sodium-Pi cotransport.

Hormonal modulation of inner ear fluids

In the cochlea, hormones such as antidiuretic hormone and adrenocorticosteroid hormones are supposed to modulate the endolymph osmolality acting on the labyrinthine water permeability, on the one hand, and on the Na+, K(+)-ATPase, on the other hand. To test the hypothesis that these hormones are involved in the inner ear fluids homeostasis, the electrochemical composition of cochlear fluids was studied in control Long Evans rats, Brattleboro rats that are genetically deprived of antidiuretic hormone, and in adrenalectomized Long Evans rats. The results demonstrated that: i) in Brattleboro rats, the endocochlear K gradient was absent whereas the endocochlear potential and the Cl concentration gradients were maintained; the K gradient was restored by the dDAVP administration; ii) in adrenalectomized rats, no modification of the electrochemical composition of endolymph occurred; the injection of bumetanide (10 mg/kg) induced a larger decrease of the endocochlear potential in adrenalectomized rats than in control animals. These results suggest that the cellular transport systems involved in the endolymph secretion may be altered by different hormones such as antidiuretic hormone and/or adrenocorticosteroid hormones. Nevertheless, the hormonal modulation of the inner ear fluid homeostasis remains to be further documented.