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The effect of water deprivation for 1 day on Na balance was measured in rats, rabbits, and sheep. In all three species, dehydration induced a considerable increase in the daily output of Na in urine. This resulted in the water-deprived animals becoming Na depleted as well as water deficient. Experiments were also designed to control for the reduced food intake that results from water deprivation in rats and rabbits. The results showed that decreased food intake was not the cause of the natriuresis and subsequent Na depletion that occurred during dehydration. When water was again made available to the dehydrated animals, a period of urinary Na retention ensued. This Na retention usually continued until the Na deficit that had accrued during the period of dehydration had been ameliorated. It seems likely that natriuresis in response to dehydration is common in mammals. We postulate that such a natriuretic response may serve a homeostatic function in buffering increases in plasma [Na] and osmolality that result from dehydration.

1. The subfornical organ, median preoptic nucleus and the organum vasculosum of the lamina terminalis (OVLT) are a series of structures situated in the anterior wall of the third ventricle and form the lamina terminalis. The OVLT and ventral part of the median preoptic nucleus are part of a region known as the anteroventral third ventricle region. 2. Data from many laboratories, using techniques ranging from lesions, electrophysiology, neuropharmacology, Fos expression, immunohistochemistry and receptor localization, indicate that the tissue in the lamina terminalis plays a major role in many aspects of body fluid and electrolyte balance. 3. The subfornical organ and OVLT lack the blood-brain barrier and detect alterations in plasma tonicity and the concentrations of circulating hormones such as angiotensin II and possibly atrial natriuretic peptide and relaxin. 4. This information is then integrated within the lamina terminalis (probably in the median preoptic nucleus) with neural signals from other brain regions. The neural output from the lamina terminalis is distributed to a number of effector sites including the paraventricular (both parvo- and magno-cellular parts) and supraoptic nuclei and influences vasopressin secretion, water drinking, salt intake, renin secretion, renal sodium excretion and cardiovascular regulation.

To ensure the accuracy and reproducibility of immunohistochemical assays for determining HER-2/neu status of patients with breast cancer, a reliable standard for monitoring assay sensitivity is necessary. We optimally fixed and paraffin processed human ovarian and breast carcinoma cell lines SKOV-3, MDA-MB-453, BT-20, and MCF-7 in quantities sufficient to meet the needs of a laboratory for the foreseeable future. The material was tested, alongside HercepTest kit cell lines (DAKO, Carpinteria, CA), by 7 breast cancer centers in the United Kingdom and France with different immunohistochemical assays and markers. The cell lines also were analyzed by fluorescence in situ hybridization (FISH) by 2 centers using HER-2/neu kits. FISH produced 100% agreement between the 2 centers: SKOV-3 and MDA-MB-453 showed HER-2/neu amplification and BT-20 and MCF-7 did not. Immunohistochemical analysis and a common evaluation method produced 100% agreement that SKOV-3 and MCF-7 showed 3+ and zero HER-2/neu overexpression, respectively. For MDA-MB-453, there was 71% (5/7) concordance of 2+ immunohistochemical staining and 86% (6/7) concordance of zero or 1 + staining for BT-20. The cell lines provide a valuable standard for gauging HER-2/neu assay sensitivity irrespective of the antibody, antigen retrieval system, detection system, or method of evaluation used.

The subfornical organ (SFO), organum vasculosum of the lamina terminalis (OVLT), and median preoptic nucleus (MnPO) were ablated either individually or in various combinations, and the effects on drinking induced by either intravenous infusion of hypertonic 4 M NaCl (1.3 ml/min for 30 min) or water deprivation for 48 h were studied. Ablation of either the OVLT or SFO alone did not affect drinking in response to intravenous 4 M NaCl, although combined ablation of these two circumventricular organs substantially reduced but did not abolish such drinking. Ablation of the MnPO or MnPO and SFO together also substantially reduced, but did not abolish, drinking in response to intravenous hypertonic NaCl. Only near-total destruction of the lamina terminalis (OVLT, MnPO, and part or all of the SFO) abolished acute osmotically induced drinking. The large lesions also reduced drinking after water deprivation, whereas none of the other lesions significantly affected such drinking. None of these lesions altered feeding. The results show that all parts of the lamina terminalis play a role in the drinking induced by acute increases in plasma tonicity. The lamina terminalis appears to play a less crucial role in the drinking response after water deprivation than for the drinking response to acute intravenous infusion of hypertonic saline.

The effect of intracerebroventricular (ICV) injections of synthetic human or rat relaxin (25 or 250 ng) on the distribution of Fos detected immunohistochemically in the rat forebrain was investigated. Following ICV relaxin, many Fos-positive neurons were observed in the periphery of the subfornical organ, dorsal part of the organum vasculosum of the lamina terminalis, throughout the median preoptic nucleus, supraoptic nucleus and hypothalamic paraventricular nucleus. Such effects did not occur following ICV injection of artificial cerebrospinal fluid or the separated A and B chains of relaxin, nor following the intravenous injection of 250 ng of relaxin. Both vasopressin and oxytocin containing neurons identified immunohistochemically in the supraoptic and paraventricular nuclei exhibited Fos following ICV relaxin, and many neurons in the medial parvocellular part of the paraventricular nucleus contained Fos. The results indicate that centrally administered relaxin may increase neuronal activity in regions of the hypothalamus and lamina terminalis which are associated with cardiovascular and body fluid regulation and oxytocin secretion.

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