Similar abnormalities of idiotype and immunoglobulin light chain expression and of cell-mediated cytotoxicity in HIV-infected humans and simian immunodeficiency virus (SIV)-infected rhesus macaques

The pathogenesis of AIDS in simian immunodeficiency virus (SIV)-infected rhesus macaques models the pathogenesis of human AIDS. We investigated whether certain immunological abnormalities associated with HIV infection and implicated in disease progression also occur in SIV infection. We observed striking parallels between the rhesus macaque humoral immune response to SIV and unusual features of the human humoral immune response to HIV infection. Anti-SIV envelope antibodies from SIV-infected macaques exhibited skewed kappa/lambda L chain usage relative to the ratio of kappa/lambda L chain usage detected on total plasma Ig. In addition, the same idiotope conserved on human anti-HIV gag, pol and env antibodies was detected with a similar distribution pattern on macaque anti-SIV env, gag and pol antibodies. Skewed Ig L chain representation and selection of a highly conserved possible dominant regulatory idiotope on antibodies against key neutralizing antigens raise the possibility that the progressive failure of the humoral immune response to SIV and HIV involves skewed oligoclonal humoral immunity. We also found that SIV-infected macaques, like HIV-infected humans, have elevated levels of CD8+ lymphocyte-mediated cytotoxicity. Cytotoxicity against human B cells was higher in CD8+ effector lymphocytes from SIV-infected macaques than in those from uninfected macaques (P < 0.05). Cell-mediated cytotoxicity against human NK cell targets was not elevated in effector lymphocytes from the SIV-infected macaques, suggesting that CTL activity was selectively elevated. Two out of seven SIV-infected macaques tested had CD8+ cytotoxic lymphocytes that selectively killed activated uninfected CD4+ macaque lymphocytes. Oligoclonal B cell responses and persistently elevated CD8+ lymphocyte-mediated cytotoxicity are consistent features of primate retroviral infections leading to AIDS. Understanding immune predispositions to these features triggered by HIV and SIV may advance new prophylactic and therapeutic strategies.

[Neonatal hypoglycemia in congenital isolated aplasia of the adenohypophysis. A case report]

We report a female newborn with prolonged neonatal hypoglycaemia and vomiting. Endocrinologic studies demonstrated the absence of the anterior pituitary hormones ACTH, STH, LH, FSH, and PRL while TSH basal secretion as well as TSH stimulation were normal at the age of 2 months. Magnetic resonance imaging showed aplasia of the anterior pituitary and a nodular ectopic posterior lobe. Substitution with prednisone resulted in normalization of blood glucose values with clinical improvement of the patient. At the age of 8 months the patient was started on recombinant human growth hormone due to poor growth; with 10 months decrease of thyrotropin secretion resulted in additional thyroxine replacement therapy.

Induction of inducible nitric oxide synthase expression by neopterin in vascular smooth muscle cells

The pteridine compounds neopterin and 7,8-dihydroneopterin serve as valuable indicators for the stimulation of the cellular immune system. Whether they exhibit distinct biochemical functions in the immunological process is at present under discussion. We show that neopterin, but not 7,8-dihydroneopterin, is a stimulus for iNOS gene expression in rat vascular smooth muscle cells in vitro. At a concentration of 20 microM, neopterin leads to an iNOS mRNA expression of 2.5 amol iNOS cDNA/micrograms total RNA. When cells were coincubated with 20 microM neopterin and 5 micrograms/ml lipopolysaccharide derived from Escherichia coli, at least an additive effect on iNOS mRNA expression could be detected (iNOS cDNA concentration was 5.0 amol/micrograms total RNA). We speculate that neopterin enhances the macrophage-induced extracellular toxicity. This might be of relevance in situations associated with excessive release of cytokines, neopterin, and nitric oxide, as observed in septic shock.

The pulmonary epithelial cell line L 2 as a new model for an inducible nitric oxide synthase expressing distal airway epithelial cell

Nitric oxide released in large amounts by inducible nitric oxide synthase (iNOS)-containing pulmonary cells plays an important role in many aspects of lung function in health and disease. The aim of this study was to establish a permanent non tumor-derived alveolar epithelial cell line that exhibits the typical characteristics of an iNOS-expressing cell. Therefore, the pulmonary epithelial cell line L2 (adult rat) was incubated with lipopolysaccharide derived from Escherichia coli (serotype 0111:B4) and different cytokines. The strongest effect on iNOS gene expression and nitric oxide release could be detected when L2 cells were coincubated with interferon-gamma + tumor necrosis factor-alpha. iNOS complementary DNA concentration was 25 amol/microliters at 9h, and nitrite/nitrate levels were 99.43 +/- 3.97 nmol/10(6) cells at 24h, respectively. Our results show that L2 cells can be regarded as an appropriate model for investigating iNOS gene expression and nitric oxide functions in alveolar epithelial cells.

The T cell receptor and AIDS pathogenesis

An idiotypic network model of AIDS pathogenesis is described in which the T cell receptor plays a role both in infection and as a target of autoimmunity. This is an extension of a previously published autoimmunity model, and provides explanations for several otherwise puzzling aspects of AIDS pathogenesis. In the model HIV-specific T cells are preferentially infected, and HIV, acting as an antigen, stimulates the expansion of the infectable pool of T cells. The HIV variants that are most strongly selected are those that are recognized by the most helper T cells. HIV and suppressor T cells are subject to the same selective environment, and consequently undergo a process of convergent selection to resemble each other more and more with time. Eventually immunity against HIV cross-reacts with suppressor T cell idiotypes, disrupting the normal regulation of helper T cells. Autoimmunity ensues. The model leads to novel vaccine and therapy approaches involving the targeting and elimination of HIV-specific T cells.

Study of morbidity of personnel with potential exposure to vinclozolin

OBJECTIVES

To examine internal exposure and targeted health outcomes of employees exposed to 3-(3,5-dichlorophenyl)-5-methyl-5-vinyl-1,3-oxazolidine-2,4-dione; chemical abstracts service (CAS) number: 50471-44-8 (vinclozolin).

METHODS

A cross sectional study of 67 men exposed to vinclozolin for one to 13 years during synthesis and formulation operations and 52 controls. Biomonitoring was based on determination of urinary metabolites that contained a 3,5-dichloroaniline (3,5-DCA) moiety. Targeted health endpoints were the same as in previous subchronic and chronic animal studies--namely, reversible changes in the concentrations of hormones of the adrenocorticotrophic and gonadotrophic feedback systems, signs of liver injury, haemolytic anaemia, cataract formation (uniquely in rats), and hormonally induced hyperplasia and tumours at high doses. The clinical investigation consisted of a medical and occupational history questionnaire, physical examination, laboratory determinations (including testosterone, LH, and FSH measurements), ultrasonography of the liver and prostate, a detailed eye examination, and routine spirometry.

RESULTS

The mean 3,5-DCA concentration for two thirds of the study group exceeded an equivalent of the vinclozolin acceptable daily intake (ADI) used for consumer regulatory purposes. Even the highest concentrations were, however, at least 10 times below the no observable adverse effect level (NOAEL) based on animal studies. Analysis of physical examination and laboratory data provided no evidence of hormonal responses induced by vinclozolin. Furthermore, no evidence of liver injury, prostate changes, cataract formation, or haemolytic anaemia was found.

CONCLUSION

There was no evidence of any health effects induced by vinclozolin among employees with potential long term exposure. In particular, no antiandrogenic effects were found.

A multicenter study of phospholipase A2 in patients in intensive care units

BACKGROUND

Multiple organ failure (MOF) is becoming the most common cause of death in patients in surgical intensive care units. In this respect, a multicenter study in four different groups of patients in surgical intensive care units was done to evaluate the role of phospholipase A2 (PLA2) in comparison with C-reactive protein (CRP) and polymorphonuclear (PMN) elastase.

STUDY DESIGN

A total of 223 patients entered the study: 73 patients with multiple injuries, 46 patients with diffuse peritonitis, 52 patients with sepsis, and 52 patients in a control group who were at a higher risk for postoperative sepsis after defined surgical interventions. The patients underwent a daily monitoring of PLA2, CRP, and PMN elastase for seven days.

RESULTS

Phospholipase A2 activity remained within the normal range in patients with multiple injuries and patients in the control group, indicating that this parameter is not influenced by the postaggression metabolism. In contrast, in patients with peritonitis, high PLA2 values were found from the beginning. The efficiency for predicting a lethal MOF was 85 percent for PLA2 (cut-off 80 U/L) in patients if determined at the day of operation. A comparably favorable efficiency (84 percent) was demonstrated for PMN elastase in patients with multiple injuries (cut-off 205 micrograms/L) measured at day one.

CONCLUSIONS

These efficiency rates of PLA2 in peritonitis and PMN elastase in multiple injuries were comparable or even better than multifactorial scoring systems used in the study. C-reactive protein did not contribute to an early estimation of the prognosis in all groups analyzed. Therefore, the measurement of PLA2 in patients with diffuse peritonitis and PMN elastase in patients with multiple injuries, as single parameters, is recommended to estimate the individual risk for the occurrence of lethal MOF.

Kinetics of Na+/H+ exchange in vascular smooth muscle cells from WKY and SHR: effects of phorbol ester

The kinetic properties of Na+/H+ exchange were investigated in vascular smooth muscle cells (VSMC) in culture from normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). Antiport activity was measured in 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein-loaded cells after nigericin-induced cytosolic acidification. Studies were performed without (control) and with pretreatment of the cells with phorbol 12-myristate 13-acetate (PMA; 200 nM). Na+/H+ exchange markedly differed between the two strains with lower Hill coefficients [1.56 +/- 0.17 (SE) vs. 2.62 +/- 0.36] and higher maximal activity (Vmax) values (55.85 +/- 5.24 vs. 31.11 +/- 2.38 mmol H+.l-1.min-1) in SHR compared with WKY cell lines. PMA markedly altered the antiport kinetics in WKY VSMC with a decrease in the Hill coefficient (1.75 +/- 0.14) without affecting Vmax (31.88 +/- 1.55 mmol H+.l-1.min-1). In VSMC from SHR, PMA had no effect on the kinetic variables investigated. Thus two kinetic abnormalities are present with respect to Na+/H+ antiport activity in VSMC from SHR compared with WKY, i.e., increased Vmax and decreased Hill coefficient. The observation that PMA does not affect the kinetics of the Na+/H+ antiport in VSMC from SHR suggests a marked degree of antiporter prestimulation in this animal model of genetic hypertension.

Hypertonic saline infusion induces activation of the lymphocyte Na+/H+ antiport and cytosolic alkalinization in healthy human subjects

The Na+/H+ antiport is a membrane transport protein that extrudes intracellular protons in exchange for extracellular sodium. Some details of its physiological and pathophysiological role remain poorly defined. Experimental evidence suggests that the antiporter is involved in the regulation of cell volume. In the present study, we therefore investigated the activity of the lymphocyte Na+/H+ antiport in nine healthy volunteers following acute hypertonic (2.5%) saline infusion (4 mmol NaCl/kg over 120 min). Antiport activity was measured after acidifying the cells with Na+ propionate (5-40 mM) using the fluorescent dye bis-carboxyethyl carboxyfluorescein. Hypertonic saline induced significant increases in plasma osmolality (308.4 +/- 2.3 vs. 293.5 +/- 2.7 mOsm/kg; P < 0.01), serum Na+ (150.8 +/- 3.7 vs. 138.9 +/- 0.5 mmol/kg; P < 0.01), and Cl- concentrations (118.0 +/- 3.9 vs. 101.1 +/- 1.0 mmol/kg; P < 0.01). Extracellular hypertonicity was followed by a stimulated activity of the lymphocyte Na+/H+ antiport with an increase in the apparent Vmax values from 2.44 +/- 0.16 to 3.27 +/- 0.34 10(-3) s-1 (P < 0.01) and a slight rise in pK, from 6.81 +/- 0.03 to 6.87 +/- 0.03 (P < 0.05) after hypertonic saline. In addition to antiport activation, cytosolic alkalinization was observed with cytosolic pH values averaging 6.90 +/- 0.02 before and 6.99 +/- 0.02 (P < 0.01) after hypertonic saline. Our results show for the first time that acute extracellular hypertonicity in man due to hypertonic NaCl loading is associated with a stimulated lymphocyte Na+/H+ antiport activity and cytosolic alkalinization.

[Chronic fatigue syndrome]

The major and minor diagnostic criteria of the chronic fatigue syndrome are described. The stages of the differential diagnosis, the diagnostic strategies and the controversies, while insisting on certain sleeping disorders are discussed. The cause of the syndrome may be a viral infection, and an anxious-depressive state may increase somatic complaints. Patients with chronic fatigue syndrome did not demonstrate a specific response to therapy. Spontaneous remission after a few years is a typical feature of this syndrome.

Co-selection in immune network theory and in AIDS pathogenesis

Co-selection is a term used to denote the mutual positive selection of individual members from within two diverse populations, such that selection of members within one population is dependent on interaction with (recognition of) one or more member(s) within the other population. Co-selection is a recurring theme of the idiotypic network model that my colleagues and I have developed. This paper discusses the role that co-selection plays in basic symmetrical network theory and in a network model that resolves the I-J paradox. It proposes that co-selection of helper T cells and HIV variants plays a role in the pathogenesis of AIDS. The AIDS model involves a role for the T cell receptor in the infection of T cells. Finally, a way in which a co-selection process may potentially be used in the prevention and therapy of harmful forms of immunity is described.

The lymphocyte Na+/H+ antiport: activation in primary hypertension and during chronic NaCl-loading

Increased activity of the Na+/H+ antiport may be a major abnormality in essential hypertension. The activity of this transport system was investigated in lymphocytes from 13 patients with untreated essential hypertension (Ht) and 13 normotensive control subjects (Nt) on an ad libitum (130-170 mmol d-1) NaCl intake. Furthermore, the effects of different states of NaCl balance on lymphocyte Na+/H+ antiport were evaluated in two groups of Nt volunteers receiving 20 vs. 300 mmol d-1 (n = 8) and 85 vs. 200 mmol d-1 (n = 14) of NaCl for 1 week each and in seven Ht patients (20 vs. 300 mmol NaCl d-1 for 1 week each). Additionally, during the 20 and 300 mmol/d NaCl intake red blood cell membrane transport was studied in eight subjects. For the determination of lymphocyte antiport activity, cells were loaded with the cytosolic pH (pHi) indicator bis-carboxyethyl carboxyfluorescein (BCECF-AM) and acidified by addition of different amounts of Na(+)-propionate (5-40 mM). Initial pHi-recovery was taken as the activity of the antiport system and plotted against pHi-values after acidification. Non-linear regression analysis yielded higher 'apparent' maximal transport rates in Ht than Nt (Nt: 2.00 +/- 0.22; Ht: (3.81 +/- 0.59) x 10(-3) s-1; P < 0.025). In contrast, baseline pHi-values and pHi-values at half-maximal activity (pK) were identical in Nt and Ht. In normotensive control subjects on an NaCl intake of 20, 85, 200 and 300 mmol d-1 for 7 d, 'apparent' maximal transport rates averaged 2.75 +/- 0.20, 2.89 +/- 0.17, 2.81 +/- 0.18 and (3.62 +/- 0.25) x 10(-3) s-1, respectively. Thus, antiport activity was significantly (P < 0.05) stimulated on the 300 mmol d-1 intake as compared to the three other NaCl intakes. The extreme intakes of NaCl (20 vs. 300 mmol d-1) in normotensive volunteers did not affect the erythrocyte Na+/K+ pump, Na+/K+ cotransport and Na+/Li+ countertransport. Our study supports the concept that a group of patients with primary hypertension exhibit an activated Na+/H+ antiport. Furthermore, our data demonstrate that a chronic high intake of NaCl is associated with an increase in lymphocyte antiport activity towards the high values observed in primary hypertension.

Establishment of new ovarian and colon carcinoma cell lines: differentiation is only possible by cytokeratin analysis

Two human ovarian (OV-MZ-10, OV-MZ-15) and two colon cancer cell lines (CO-MZ-5, CO-MZ-6) were newly established in permanent cell culture. These cell lines have been maintained in vitro for 5-6 years, the passage number varying from 25 to 228. They were established from ascites or solid tumours at the time of primary surgery. By clinical and histopathological judgement alone all four cell lines would have been interpreted as ovarian cancer cell lines. Morphological criteria or the expression of the tumour-associated antigens CA-125 and CEA allowed no differential diagnosis. Only the analysis of the expression of different cytokeratins and vimentin enabled us to verify the different origin of the cell lines. Ovarian cancer cell lines, in contrast to the colon cancer cell lines, are positive for the expression of cytokeratin (CK) 7 and for vimentin. CK 20 proved to be the marker with the best discrimination. CK 20 was found exclusively in the colon carcinoma cell lines, but not in the ovarian carcinoma cell lines. The evaluation of cytokeratin expression is a helpful diagnostic modality in differentiating between adenocarcinoma cell lines derived from ovarian and colon tumours.