Peripheral B cells with intracytoplasmic mu chains in HIV infection.

Besides the major alteration of T lymphocytes, B-cell anomalies have been reported in HIV infection, related to late stages of B-cell maturation, and considered to result from the dysregulation of T/B interactions. Because T cells are also involved in the control of lymphopoiesis and/or because of specific alterations of the B lineage, anomalies of B-cell maturation could occur in HIV-infected patients. We investigated the presence of immature pre-B lymphocytes, characterized by cytoplasmic mu chains, in 35 peripheral blood samples from healthy controls, 82 from HIV-positive/non-AIDS patients, and 45 from AIDS patients. Significant numbers of such cells were observed in 48% of HIV-seropositive patients and in 40% of the patients with AIDS disease. The presence of pre-B cells correlated with higher numbers of CD8+ and/or CD57+ cells and of peripheral lymphocytes. These data suggest that B-cell dysregulation in HIV infection may lead to the abnormal release of immature B cells in the peripheral blood. This observation may be interpreted as a sign of bone marrow activity.     

Expression of human NKRP1A by CD34+ immature thymocytes: NKRP1A-mediated regulation of proliferation and cytolytic activity

In this study, we show that NKRP1A is expressed and functions on a subset of immature human thymocytes. We took advantage of the monoclonal antibody (mAb) 191B8 that was obtained by immunizing mice with cultured human thymocytes characterized by an immature surface phenotype [CD2^? CD3^? CD4^? CD8^? stem cell factor receptor (SCFR)⁺] and expressing cytoplasmic CD3? chain. The 191B8 antibody homogeneously reacted with the immunizing population but not with most unfractionated thymocytes. It stained a minor population of resting immature thymocytes co-expressing CD34, SCFR, or both. Following culture of the CD34⁺ or CD34^? fractions of CD2^? CD3^? CD4^? CD8^? purified immature thymocytes with recombinant interleukin-2 (rIL-2), the 191B8-defined antigen was expressed on virtually all cells even when 191B8⁺ cells were removed from the starting population. On the other hand, no 191B8⁺ cells were detected in fresh or cultured thymocytes expressing a more mature phenotype. Biochemical analysis of 191B8 mAb-reactive molecules revealed, under non-reducing conditions, two bands displaying apparent molecular masses of 80 and 44 kDa and a single band of 44 kDa under reducing conditions. Digestion with proteases indicated that the 80-kDa form represented a homodimeric form of two 44-kDa molecules, while deglycosylation with N-glycanase suggested the existence of four N-glycosylation sites. Transfection of COS7 or NIH3T3 cells with hNKRP1A cDNA showed that the 191B8 mAb recognized NKRP1A as shown by both immunofluorescence analysis and immu-noprecipitation experiments. Functional studies showed that the 191B8/NKRP1A molecule mediated strong inhibition of the cytolytic activity of culturd CD2^? CD3^? immature thymocytes against a panel of tumor target cells. More importantly, 191B8 mAb induced proliferation of CD2^? CD3^? fresh thymocytes which was not increased by rIL-2. Thus, we propose that NKRP1A molecules, which are expressed in highly immature thymocytes, may play a regulatory role in their growth and function.     

Assessment by flow cytometry of peripheral blood leukocyte enzymatic activities in HIV patients

Leukocyte enzymatic activities are important in non-specific protection against bacterial infections, but traditional methods for the detection of intracellular enzymatic activities rely on cumbersome and complex assays. The development of specific substrates, which become fluorescent upon degradation of the biomolecule after its passive entry into intact cells, permits a simplified evaluation of leukocyte enzymatic activities. We have used this method to assess intracellular elastase, collagenase and cathepsin D activities of peripheral blood leukocytes using flow cytometry in a series of HIV patients and healthy controls. Monocytes displayed the highest enzymatic activities for the three proteases tested. In HIV-infected patients, the collagenase and cathepsin D activities of monocytes were significantly lower, whereas the elastase and cathepsin D activities of polymorphonuclear cells were elevated. Slightly higher elastase activity was detected in the lymphocytes of patients. This study demonstrates the feasibility of this new method for the study of intracytoplasmic enzymatic activities. Significant variations were observed in the peripheral blood of HIV-infected patients and different patterns were especially evident in monocytes and polymorphonuclear cells.     

Massive CA1/2 neuronal loss with intraneuronal and N-terminal truncated Abeta42 accumulation in a novel Alzheimer transgenic model

Alzheimer's disease (AD) is characterized by a substantial degeneration of pyramidal neurons and the appearance of neuritic plaques and neurofibrillary tangles. Here we present a novel transgenic mouse model, APP(SL)PS1KI that closely mimics the development of AD-related neuropathological features including a significant hippocampal neuronal loss. This transgenic mouse model carries M233T/L235P knocked-in mutations in presenilin-1 and overexpresses mutated human beta-amyloid (Abeta) precursor protein. Abeta(x-42) is the major form of Abeta species present in this model with progressive development of a complex pattern of N-truncated variants and dimers, similar to those observed in AD brain. At 10 months of age, an extensive neuronal loss (>50%) is present in the CA1/2 hippocampal pyramidal cell layer that correlates with strong accumulation of intraneuronal Abeta and thioflavine-S-positive intracellular material but not with extracellular Abeta deposits. A strong reactive astrogliosis develops together with the neuronal loss. This loss is already detectable at 6 months of age and is PS1KI gene dosage-dependent. Thus, APP(SL)PS1KI mice further confirm the critical role of intraneuronal Abeta(42) in neuronal loss and provide an excellent tool to investigate therapeutic strategies designed to prevent AD neurodegeneration.     

Hypertension and neuroticism

324 normo- and hypertensive subjects were investigated for neurotic symptoms during outpatient screening for arterial hypertension. The patients were randomly selected and subdivided into three groups: 'new' hypertensives, 'old' hypertensives and normotensives. Neurotic symptoms were evaluated using the Kellner and Sheffield Symptom Rating Test. The mean values thus obtained were adjusted using covariance analysis, with age and sex as the covariants. The 'new' hypertensives scored significantly lower for total neuroticism, depression and inadequacy than the normotensives. They also differed from the 'old' hypertensives, scoring significantly lower for total neuroticism, anxiety, somatization and inadequacy. However, no differences were revealed between the 'old' hypertensives and the normotensives. The significance and implications of these psychological differences are discussed.     

Mechanism of impaired urinary concentration in chronic primary glomerulonephritis

To define the role of medullary damage and the influence of solute load and blood pressure (BP) in impairing urinary concentration, patients with chronic glomerulonephritis were investigated by histological and functional studies. In 59 biopsy specimens, the degree of medullary fibrosis was correlated inversely with urinary specific gravity and was significantly greater in hypertensive than in normotensive subjects. The following clearance studies were carried out in patients with a GFR of 15 to 40 ml/min in maximal antidiuresis: (1) Eight patients were studied while receiving a high sodium and protein diet and then after 1 week of low sodium, low protein diet; (2) ten patients were loaded with hypertonic saline (3%) to increase urine volume up to 25 to 30% of GFR; (3) the concentrating ability was compared in 15 normotensives and 15 hypertensives with comparable GFR; (4) the concentrating ability was studied in nine hypertensive patients before and after drug-induced normalization of BP. In (1) no change occurred in maximal urine osmolality (UOsm) even if fractional sodium excretion and filtered load of urea were reduced. In (2), values of UOsm fell below those of plasma osmolality. In (3), UOsm and negative free-water generation were lower in hypertensive than in normotensive subjects. In (4), normalization of BP was not associated with any change in UOsm. These results indicate that osmotic diuresis does not play a critical role in reducing urinary concentration. This defect is better accounted for by an intrinsic medullary damage, enhanced in hypertensive patients, which may impair the permeability of collecting ducts to water.     

Toxicity, biodegradability, and accumulation of a number of Cl/N-containing compounds for classification and establishing water quality criteria

The evaluation of the ecotoxicity of chemical compounds is often hampered by the scarcity of the literature data on toxicity, biodegradability, and accumulation. In this study additional data on 16 Cl/N-containing organic compounds were gathered by laboratory experiments. For assignment to so-called gray or black lists, two different classification schemes were used. According to both schemes 3-nitrotoluene, 1,2- and 1,3-dichlorobenzene, the 1-chloro-nitrobenzenes, 2,3-dichloronitrobenzene, 2-chloroaniline, and 2-chloro-4-nitroaniline were marked as black list substances, primarily based on poor biodegradability; 2- and 4-nitrotoluene, nitrobenzene, and 2-methoxyaniline were classified as gray list substances. For 3- and 4-methoxyaniline and 1,4-dichlorobenzene no agreement in classification was obtained. Additionally, water quality criteria are proposed for 2-, 3-, and 4-nitrotoluene and nitrobenzene, based on long-term toxicity data: respectively 0.3, 0.2, 0.4, and 1.0 mg/liter.