Biomedical subjects
Publications and source records attributed to G Wallach.
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Adrenalectomized-ovariectomized (ADX-OVX) rats were given tail vein infusions of [3H]corticosterone, dexamethasone, cortisol, deoxycorticosterone or progesterone in doses around 10 nmoles/kg body weight. After a 30-60 min uptake period, cell nuclei were isolated from 9 brain regions and pituitary. Patterns of cell nuclear retention of [3H]corticosterone and [3H]dexamethasone differed: the former steroid was highest in hippocampus and septum and low in pituitary; the latter steroid was highest in pituitary and more uniformly distributed in the brain. The other 3H steroids showed very little cell nuclear labeling in vivo. In contrast, in vitro cytosol binding in hippocampus for [3H]progesterone, cortisol, deoxycorticosterone, and dexamethasone was 40-60% of that observed for [3H]corticosterone. The specificity of cell nuclear binding in slices of hippocampus in vitro was similar to that observed for cytosol binding. Reasons for the selectivity of in vivo cell nuclear labeling remain to be discovered but the selectivity does not appear to be an intrinsic feature of the receptors themselves. The pattern of in vivo labeling by [3H]corticosterone and [3H]dexamethasone differs from the in vivo distribution of [3H]estradiol in ADX-OVX rats using the same dissection procedure and this demonstrates the regional differentiation within brain of steroid hormone uptake and 'receptor' processes.
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In an attempt to relate binding of 3H-corticosterone and 3H-dexamethasone to their respective potencies in blocking pituitary-adrenal activity, cytosol binding in vitro and cell nuclear binding both in vivo and in tissue slices in vitro were studied in hippocampus, hypothalamus, and anterior pituitary of adrenalectomized rats. It was found that the extremely potent glucocorticoid dexamethasone has a different pattern of binding than corticosterone in the brain and in the anterior pituitary. 1) In cytosol, differences in the estimated binding capacities in a particular tissue for 3H-corticosterone and 3H-dexamethasone and different rates of inactivation in the ability to bind the two steroids are observed. 2) For 3H-corticosterone, cytosol binding in hippocampus is higher than that in hypothalamus, and cell nuclear binding follows the same pattern. For 3H-dexamethasone, cytosol binding is again higher in the hippocampus than in hypothalamus but cell nuclear binding in the two structures is not significantly different. With respect to the anterior pituitary, binding to cell nuclei is higher for 3H-dexamethasone, while the binding to cytosol macromolecules is higher for 3H-corticosterone. 3) In vivo and in vitro cell nuclear binding for both steroids showed the same pattern among the three tissues, but in vivo data showed more distinctly the preference of 3H-dexamethasone for the anterior pituitary and the preference of 3H-corticosterone for the hippocampus. 4) When labeled in tissue slices, cell nuclear radioactivity appears to be bound to macromolecules. 5) Steroid metabolism does not occur in slices during 60 min in vitro at 25 C and cannot account for the observed tissue differences in binding. The existence of more than one population of corticosteroid-binding sites in brain and in anterior pituitary is suggested. The results are consistent with the view that the dexamethasone blockade of stress-induced ACTH release is mediated by the anterior pituitary, while the high specificity of cotricosterone binding in the hippocampus implies a specific but as yet undetermined effect of the hormone in this brain area, an effect which may not be directly related to regulation of ACTH secretion.
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The National Immunization Information Hotline (NIIH) has been providing information regarding immunizations to the public and to health care professionals since March 1997. We describe the operations of the NIIH, its experience over the first two and a half years of operation and lessons learned for other immunization hotlines. From 1998-2000, the hotline answered 246,859 calls. Calls concerning immunization information requests totaled 175,367; data about the calls were collected from 35,102. Approximately a third of the 35,102 calls were from health care providers. Of the remaining calls from the public, the greatest number of calls concerned childhood immunizations. Immunization schedule queries from the public increased 323.0% from 1998 to 2000. While the major goal of the NIIH is to provide accurate and reliable information to the public and to health care providers, data from the hotline can be used to monitor changes over time in calls concerning inquiries about the immunization schedule in addition to other variables of interest.
Data from the National Immunization Information Hotline (NIIH) concerning vaccine adverse event inquiries were analyzed from 1998 to 2000 (total n = 23,841 [public n = 14,330; health care professionals n = 9,511]). Approximately 20% of calls from the public from 1998 to 2000 concerned vaccine adverse events. These calls increased 199.5% from 1998 (n = 422) to 1999 (n = 1,264), then declined 12.4% from 1999 to 2000 (n = 1,107). A Lexus Nexus search showed that the number of news stories mentioning vaccine safety showed a similar pattern. Women were more likely to call the NIIH concerning vaccine adverse events than men, and persons 40-59 years old and persons 60 years old and over were less likely to call about vaccine adverse events than those 20-39 years. The parallel trends in news stories mentioning vaccine safety and calls to the NIIH concerning adverse events suggests that news stories may stimulate questions about vaccine safety. Understanding that news stories may elicit questions about vaccine adverse events and examining the characteristics of persons who ask vaccine adverse event questions may guide future informational interventions toward those most in need.