Renin gene and angiotensin II AT1 receptor gene expression in the kidneys of normal and of two-kidney/one-clip rats

This study aimed to investigate the inter-relation between the angiotensin II (ANG II) AT₁ receptor and renin gene expression in rat kidneys. To this end, renin mRNA levels and mRNA levels for AT_1a and AT_1b were assayed by RNase protection in the kidneys of normal rats, in animals treated with the AT₁ antagonist losartan and in rats bearing 0.2-mm left renal artery clips for 2 days. In normal rats, we found a negative correlation between renin mRNA levels and AT_1a receptor mRNA levels. Losartan led to a fourfold increase in renin mRNA levels without changing AT₁ receptor mRNA levels. Unilateral renal artery clipping increased renin mRNA levels fourfold in the clipped kidney and suppressed renin mRNA levels in the contralateral kidneys. AT₁ receptor mRNA levels were not changed in the contralateral intact kidneys, but were significantly decreased by 15–25% in the clipped kidneys. Renin mRNA levels were inversely correlated to AT_1a mRNA levels in the clipped, but not in the contralateral, kidneys. Our findings suggest that the systemic activity of the renin angiotensin system has no regulatory influence on renal AT₁ receptor gene expression. Renin mRNA levels in normal and in clipped kidneys appear to be negatively determined by the level of AT_1a receptor gene expression. Thus modulation of AT_1a receptor gene expression could be a pathway for indirect modulation of renin gene expression by ANG II. This conclusion is in agreement with the observation that AT₁ receptor antagonists are powerful stimulators of the renin system.     

Divergent regulation of vascular endothelial growth factor and of erythropoietin gene expression in vivo

There is accumulating evidence from in vitro experiments that the gene expression of the vascular endothelial growth factor (VEGF) is, like that of the erythropoietin (EPO) gene, regulated by the oxygen tension and by divalent cations such as cobalt. Since the information about the regulation of VEGF gene expression in vivo is rather scarce, this study aimed to examine the influence of hypoxia and of cobalt on VEGF gene expression in different rat organs and to compare it with that on EPO gene expression. To this end male Sprague-Dawley rats were exposed to carbon monoxide (0.1% CO), hypoxia (8% O₂ ) or to cobalt chloride (12 and 60 mg/kg s.c.) for 6 h. mRNA levels for VEGF- 188, -164, and -120 amino acid isoforms in lungs, hearts, kidneys and livers were semiquantitated by RNase protection. For these organs we found a rank order of VEGF mRNA abundance of lung >> heart > kidney = liver. EPO mRNA levels were semiquantitated in kidneys and livers. Hypoxia, CO and cobalt increased EPO mRNA levels 60-fold, 140-fold and 5-fold, respectively, in the kidneys, and 11-fold, 11-fold and 3-fold, respectively, in the livers. None of these manoeuvres caused significant changes of VEGF mRNA in lung, heart or kidneys. Only in the livers did hypoxia lead to a significant (50%) increase of VEGF mRNA. These findings suggest that, in contrast to the in vitro situation, the expression of the VEGF gene in normal rat tissues is rather insensitive to hypoxia. In consequence, the in vivo regulation of the VEGF and the EPO genes appear to differ substantially, suggesting that the regulation of the VEGF and EPO genes may not follow the same essential mechanisms in vivo. Received: 31 July 1995/Received after revision: 20 November 1995/Accepted: 27 November 1995     

Analysis of lymph nodal metastases in malignant melanoma using the poisson probability paradigm and Bayes rule

This article deals with and formalizes 2 notions common to the practice of pathology. The first is that the number of lymph nodes found positive for metastasis relates directly to the total number of lymph nodes examined. The second is that for any patient, there is a chance that the absence of lymph node metastases is a false-negative result. I introduce the Poisson probability density function to deal with the first notion and the Bayes probability rule to deal with the second. To illustrate the insight these 2 models provide, I apply them to data regarding lymph nodal metastases in malignant melanoma. In this preliminary study, the results of these 2 models correlate well with observed survival probabilities in patients with stage N0 melanoma and with observed rates of false-negative results in sentinel lymph node biopsy technology. With further development, the combination of these models should provide a way to estimate the probability of nodal metastasis when, in fact, none have been observed. Thus, these models might provide useful tools for evaluating patients with stage N0 malignant neoplasms.     

Differentiating moderate and severe depression using the Montgomery-Asberg depression rating scale (MADRS)

BACKGROUND: MADRS cut-off scores for moderate and severe depression were estimated in relation to the Hamilton Depression Rating Scale (HAMD(17)) and the Clinical Global Impressions Scale (CGI). METHOD: HAMD(17), MADRS, and CGI ratings from patients with major depression (DSM-IV) were analyzed (N=85). Receiver operating characteristics (ROC) curves were applied. RESULTS: Mean age was 51.4+/-14.5 years, 69% were female. Mean MADRS scores were 23.4+/-13.2, HAMD(17), MADRS, and CGI scores were highly correlated (r>0.85; P<0.0001). Best separation between moderate and severe depression according to CGI criteria was achieved with a MADRS score of 31 (sensitivity 93.5%, specificity 83.3%). LIMITATIONS: Studies to validate severity gradations including DSM-IV or ICD-10 diagnostic severity categories are recommended. CONCLUSIONS: Empirically based MADRS cut-off scores to separate moderate from severe depression on the basis of HAMD(17) and CGI severity ratings in patients with major depression were yielded.     

Dermatoglyphic peculiarities in patients with Williams-Beuren syndrome

The dermatoglyphic patterns of fingertips and palms of 115 patients with Williams-Beuren syndrome (WBS) were analysed and compared with the data from 199 control individuals from Germany. The following combination of dermatoglyphic patterns appears to be characteristic to WBS: an excess of whorls on all fingertips; high termination values of the main lines D, B, and A; frequent absence of C triradius (C°); high frequencies of ulnar loops on the hypothenar and distal loops on the 2nd, 3rd, and 4th inter digital areas, of distal axial triradii t", and of abnormal palmar creases such as simian crease and Sydney lines. The combination of fingertip and palmar patterns expressed by a “Log.Score-Index,” provides a high degree of discrimination between the WBS patients (92%) and the control group (88%). A “phantom picture” for WBS was constructed, which can be used for its diagnosis. © 1994 Wiley-Liss, Inc.     

Consumption of solutions containing sodium chloride is enhanced in female oxytocin-deficient mice

Intact and ovariectomized oxytocin (OT)-deficient (OT-/-) and wild-type (OT+/+) mice were tested for consumption of 0.5 M NaCl solution or tap water in a 2-bottle choice test. During 3 days of acclimation, voluntary ingestion of NaCl was equal between genotypes. After overnight fluid deprivation, intact OT-/- mice ingested 2 times more NaCl solution than OT+/+ mice in the 6th hr, but not the 1st hr, after reintroduction of fluid. Ovariectomized mice consumed less than intact mice after overnight fluid deprivation. When a 0.2 M NaCl solution was administered for 6 days in ovariectomized mice, OT-/- mice voluntarily consumed greater amounts than OT+/+ mice. After overnight fluid deprivation, consumption by OT-/- mice was 3 times that of OT+/+ mice at 1 hr and 2-fold greater after 6 hr. Enhanced intake of NaCl-containing solutions in female OT-/- mice suggests that central OT may be an important inhibitor of sodium consumption.     

Cross-reactive trinitrophenylated peptides as antigens for class II major histocompatibility complex-restricted T cells and inducers of contact sensitivity in mice. Limited T cell receptor repertoire

The induction of contact sensitivity in mice by hapten reagents such as trinitrochlorobenzene (TNCB) involves the activation of class II major histocompatibility complex (MHC)-restricted, hapten-specific, CD4⁺ T cells. Reports from different laboratories have indicated that the relevant antigenic epitopes in such reactions might include hapten-conjugated, MHC class II-associated peptides. This study for the first time directly demonstrates that hapten-peptides account for the majority of determinants recognized by trinitrophenyl (TNP)-specific CD4⁺ T lymphocytes. The sequences of those TNP carrier peptides do not have to be related to mouse proteins. Thus, we show that TNP-modified peptides derived from mouse IgG, pigeon cytochrome c or staphylococcal nuclease known to bind to I-A^b or from λ represser with specificity to I-A^d as well as TNP-proteins such as bovine serum albumin, ovalbumin or keyhole limpet hemocyanin all create class II-restricted hapten determinants for a number of TNP-specific T cell clones and hybridomas. All of these cells were induced with cells modified by trinitrobenzene sulfonic acid (TNBS). In addition, we present arguments indicating that individual TNP-specific helper T cells may cross-react with different TNP-peptides bound to identical class II molecules. Chemical treatment of antigen-presenting cells with TNCB or TNBS may thus result in a limited number of particularly repetitive immunodominant hapten epitopes. Immunodominant epitopes were also indicated by an overrepresentation of the TCR elements Vβ2 and Vα10 in I-A^b/TNP-specific T cells. Most importantly, however, we demonstrate that TNP attached to lysine 97 in the staphylococcal nuclease peptide 93–105 (i.e. a clearly “non-self” sequence) is able to prime mice for subsequent elicitation of contact sensitivity by TNCB in the absence of foreign protein. We take this to indicate that those TNP-peptide determinants defined by us as immuno-dominant are responsible for the induction of contact sensitivity to haptens.