[Multivariate statistical methods for the exploratory analysis of multidimensional data].
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Chemistry, Pharmaceutical↗
Biomedical subjects
M Schaefer
Publications and source records attributed to M Schaefer.
Home and health--on solid foundations?
This article is based on a WHO survey confirming that a large part of humanity lacks adequate shelter or knowledge of how to obtain the best possible health benefits from housing. The reasons for this state of affairs, and the health sector's role in overcoming it, are discussed.
Health Policy↗
[Female hypospadias: a rare cloacal abnormality].
The term "hypospadia feminis" means a congenital false urethral opening in the anterior vaginal wall proximal to the hymenal ring. In comparison to the male hypospadia it is a rare event. Obligatory an obstructive uropathy is found, but the pathophysiology remain obscure.
Female↗
Antigen-presenting cells for unprimed T cells.
The triggering requirements of T cells differ for primed and unprimed cells: primed T cells can be triggered to produce lymphokines without viable antigen-presenting cells (APCs), apparently by crosslinking the T-cell receptor (TCR). Unprimed T cells do, however, require viable APCs and here Jonathan Sprent and Mary Schaefer review what type of cells can carry out this function, with particular reference to APCs for unprimed CD8+ cells.
Animals↗
Antigen-presenting cells for Lyt-2+ cells. II. Primary mixed-lymphocyte reactions stimulated by Ia+ dendritic cells and Ia- peritoneal exudate cells.
Information was sought on the antigen-presenting cells (APC) required for stimulating primary mixed-lymphocyte reactions (MLR) by unprimed Lyt-2+ cells in the absence of added lymphokines. Like L3T4+ cells, Lyt-2+ cells gave very high MLR in response to H-2-different dendritic cells (DC). Surprisingly, high MLR were also elicited by thioglycollate-induced peritoneal exudate cells (PEC), including Ia- PEC; these cells were non-immunogenic for L3T4+ cells. Since PEC consisted almost entirely of macrophages (M phi), the data suggest that at least two different cell types, DC and M phi, can express APC function for unprimed Lyt-2+ cells. Since resident peritoneal M phi and in vitro cultured PEC were poorly immunogenic, the APC function of M phi might be limited to a subset of these cells, e.g. to immature M phi.
Animals↗
New needs in health management.
National health development policies demand the building of operational and management capacities. A WHO study has identified key requirements in these areas and has found that few countries are in a position to meet them.
Delivery of Health Care↗
[Drug consumption statistics--a method for comparing studies].
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Drug Utilization↗
Effects of thoracic epidural anesthesia on systemic hemodynamic function and systemic oxygen supply-demand relationship.
The effects of thoracic epidural anesthesia (TEA) on total body oxygen supply-demand ratio are complex due to potential influences on both O2 delivery (QO2) and consumption (VO2). One hundred and five patients undergoing abdominal aortic surgery were randomly assigned to one of three groups to compare the cardiovascular and metabolic responses associated with (1) thoracic epidural anesthesia plus light general anesthesia (group TEA); (2) general anesthesia with halothane (group H); and (3) neuroleptanalgesia (group NLA). Values of cardiac index (CI) and QO2 were less intraoperatively in the TEA group than in the H or NLA groups, while VO2 values were similar. VO2 during recovery was greater in both the TEA and NLA groups than in the H group. Consequently the oxygen supply-demand ratio (QO2/VO2) was less in the TEA group throughout the perioperative period and about 30% below baseline values during early recovery. At comparable VO2, CI and mixed venous O2 saturation were always less in the TEA group than in the NLA group. Heart rate was slowest intraoperatively during TEA, and stroke work was less with TEA than with NLA. As cardiac filling pressure and systemic vascular resistance did not differ among the three groups, reduced adaptation of CI to tissue O2 needs during TEA was attributed to negative inotropic and chronotropic effects of the sympathetic blockade. We conclude that in patients undergoing abdominal aortic surgery, TEA has no apparent advantage over general anesthesia.
Anesthesia, Epidural↗
Antigen-presenting cells for Lyt-2+ cells. I. Stimulation of unprimed Lyt-2+ cells by H-2 different Thy-1-Ia- cells prepared from spleen and bone marrow.
In agreement with previous studies on Ia- tumor cells, evidence is presented that primary MLR of purified Lyt-2+ T cells to class I alloantigens can be elicited by a minor population of Thy 1- Ia- cells present in normal spleen, bone marrow, and day-13 fetal liver; these cells are non-stimulatory for L3T4+ T cells. The data strengthen the view that primary responses of Lyt-2+ cells do not require the presence of Ia+ cells.
Animals↗
Capacity of purified unprimed Lyt-2+ cells to reject Ia- H-2-different tumor cells in the Winn assay.
To examine which cells participate in primary anti-H-2 responses to Ia- tumors in vivo, irradiated mice were injected intracutaneously with small doses of tumor cells mixed with purified populations of host-type lymphoid cells. Studies with three different Ia- H-2-different tumors showed that purified unprimed Lyt-2+ cells were highly efficient at suppressing tumor growth. Lyt-2+ cells were appreciably more effective at suppressing tumor growth than unseparated T cells, and no protection was seen with injection of L3T4+ cells (except in the late states of tumor growth). It is suggested that class I alloantigens on the tumors are directly immunogenic for Lyt-2+ cells. Without need for help from L3T4+ cells, the responding Lyt-2+ cells rapidly differentiate into cytotoxic cells and destroy the tumor cells before macroscopic tumors can arise.
Animals↗
Role of T cell subsets in lethal graft-versus-host disease (GVHD) directed to class I versus class II H-2 differences. I. L3T4+ cells can either augment or retard GVHD elicited by Lyt-2+ cells in class I different hosts.
Detailed information was sought on the capacity of purified Lyt-2+ cells to mediate lethal graft-versus-host disease (GVHD) directed to class I H-2 differences. When B6 Lyt-2+ cells were transferred to irradiated class I-different (B6 x bm 1)F1 mice, three different patterns of lethal GVHD were observed. First, rapid death from hematopoietic failure occurred when Lyt-2+ cells were transferred together with host-type marrow cells; this form of GVHD probably reflected direct destruction of stem cells by Lyt-2+ cytotoxic cells. Second, a pattern of late-onset, chronic GVHD resulting in death only after 4-6 wk occurred when Lyt-2+ cells were supplemented with donor marrow. This syndrome developed in the apparent absence of L3T4+ cells and was observed with either high or low doses of Lyt-2+ cells and with either light or heavy irradiation of the host. Third, an acute form of GVHD resulted when Lyt-2+ cells plus donor marrow cells were supplemented with exogenous help, i.e., by adding small doses of donor L3T4+ cells or injecting the hosts with rIL-2. Although L3T4+ cells potentiated GVHD when injected in small doses, supplementing Lyt-2+ cells with large doses of L3T4+ cells paradoxically led to marked protection; symptoms of GVHD were mild and no deaths occurred.
Animals↗
Test-retest reliability of the MSLT.
The test-retest reliability of the Multiple Sleep Latency Test (MSLT) was evaluated in 14 healthy normal subjects. Each slept a single night in the laboratory (8 h time in bed) and received the MSLT the following day (1000, 1200, 1400, and 1600 h) on two occasions separated by 4-14 months. Mean sleep latency (four tests) was highly reliable from MSLT to MSLT (r = 0.97, p less than 0.001). The test-retest reliability did not change as a function of the interval of time between tests or as a function of the level of sleepiness (range = 4-20 min) within the population. However, as the number of tests comprising the MSLT was reduced below three, the reliability was reduced such that only 50% or less of the variance could be predicted.
Adult↗
Gd-DOTA, a potential MRI contrast agent. Current status of physicochemical knowledge.
The complex (Gd-DOTA) meglumine has recently been used as an MRI contrast agent in humans. Due to its particularly interesting physicochemical properties, the risk of in vivo dissociation of the complex is reduced. Indeed, as a result of the macrocyclic nature of the DOTA ligand, Gd-DOTA appears very stable, demonstrating a calculated conditional stability constant of 10(22.19) at pH = 7. Other characteristics making Gd-DOTA a positively attractive compound include slow dissociation kinetics inherent in the rigidity of the macrocycle and marked specific affinity of DOTA for gadolinium in comparison with other endogenous ions. Finally, although the relaxivity R1 of Gd-DOTA at 20 MHz appears similar to that of Gd-DTPA, Gd-DOTA demonstrates higher paramagnetic efficacy at low field strength due to greater symmetry of the complex. Such promising properties open up wide prospects for the use of Gd-DOTA in MRI.
Contrast Media↗
[Pathology of the urachus: diagnosis and therapy].
Urachal abnormalities may provoke especially urinary tract infections. They become symptomatically first of all in the childhood. The development of urachal carcinoma is particularly described in the adult. The features of diagnosis and treatment will be presented with clinical examples. The only possible treatment of those malformations is the operative removal of the urachal tissue. This is most important to prevent as well urinary tract infections as the malignant degeneration of the urachal malformations.
Abdominal Neoplasms↗
Detection of cholecystokinin-58 in human blood by inhibition of degradation.
Although cholecystokinin-58 (CCK-58) is a major molecular form stored in the intestine, it has not yet been shown to be released into the circulation. This report describes in vitro degradation of CCK-58 in human blood and plasma and the molecular forms detected when this degradation is inhibited. After incubation of CCK-58 for 150 min between 20 and 24 degrees C, approximately 60% of immunoreactivity recovered was degraded to smaller immunoreactive forms. Storage of the 150-min incubate at -20 degrees C for 3 days greatly increased the observed degradation to 85%. When CCK-58 was added in vitro to blood, similar degradation occurred. Degradation of CCK-58 could be inhibited by addition of acid. Blood was obtained 1 h after a test meal designed to stimulate CCK release. The pH was lowered during collection and processing of blood and plasma to inhibit in vitro degradation of cholecystokinin. This method permitted the detection of significant amounts of CCK-58 in circulation.
Cholecystokinin↗
[Comparison of prescribed and defined daily doses (DDD) of selected antihypertensives--problems and conclusions].
The comparison of prescribed and defined daily doses of 21 antihypertensive drugs showed minor to major differences, which have an impact on how to assess future drug demand and how to evaluate the therapeutic equivalence of various drugs. Relating problems concerning prescribing habits of drugs and research in drug demand are being discussed.
Antihypertensive Agents↗
Properties of purified T cell subsets. II. In vivo responses to class I vs. class II H-2 differences.
Highly purified populations of C57BL/6 (B6) L3T4+ and Lyt-2+ T cell subsets were compared for their capacity to exert alloreactivity to class I vs. class II H-2 differences in vivo. B6 Lyt-2+ cells responded strongly to the class I different mutant, bm1, as manifested by DNA synthesis in the spleen of irradiated mice followed by entry of blast cells into thoracic duct lymph, induction of splenomegaly in newborn mice, production of lethal GVHD in irradiated mice, and skin allograft rejection. By all of these parameters, B6 Lyt-2+ cells showed almost total unresponsiveness to the class II-different mutant, bm12. Reciprocal results were observed with B6 L3T4+ cells, these cells responding strongly against bm12 but not against bm1. In the case of purified T cell subsets from other strains, CBA/Ca and B10.BR L3T4+ cells both responded well to a full H-2 difference. Responses by Lyt-2+ cells from these strains were weaker, especially for CBA/Ca cells. The implications of these findings are discussed.
Animals↗
Modulation of a respiratory motor program by peptide-secreting neurons in Aplysia.
Respiratory pumping of the gill and siphon of Aplysia californica is a fixed-action pattern coordinated by a defined set of interneurons and motor neurons. In semi-intact preparations of the gill and siphon innervated by the abdominal ganglion, respiratory pumping is facilitated for a prolonged period following activation of the peptidergic bag cell neurons. The induced changes in contractile behavior of the gill and siphon correlate with cell-specific actions of the bag cells on motor neurons regulating these organs. Our results suggest that peptidergic neurons can alter the expression of a fixed pattern of behavior by modulating the excitability of motor neurons controlling the behavior.
Animals↗