Inhibition by heparin-modulated antithrombin III of amidolysis catalysed by m beta-acrosin.

Purified m beta-acrosin catalysed amidolysis of several p-nitroanilides with C-terminal arginine residues. Antithrombin III inhibited amidolysis catalysed by the enzyme. This effect of antithrombin III was potentiated by heparin, and to a modest extent by heparan sulphate, cellulose sulphate, dextran sulphate and xylan sulphate. De-N-sulphated heparin, de-N-sulphated N-acetylated heparin, heparin of low relative molecular mass, chondroitin 4-sulphate, chondroitin 6-sulphate, dermatan sulphate and hyaluronic acid were ineffective.     

The sociocultural context of nursing in Japan

Both by the standards of American nurses and in the eyes of the Japanese public, nurses in Japan appear subservient. In this paper I explore this situation from three perspectives. Most Japanese nurses lack a sense of professionalism which the nursing elite in Japan as well as sociological theory attributes to the low educational levels of the nurses. The second perspective investigates the nurses' functional role as intermediary between the medical world and the many patients who regard physicians as socially distant. Thirdly, Japanese nurses might be considered the housewives of the hospital in terms not only of their physical duties but also of their caretaking role. If the housewife analogy holds, the values, behavior, and attitudes that give Japanese housewives their satisfaction and their autonomy would considerably alter the role of the nurse in the delivery of cosmopolitan medical care.     

Ultrastructural changes induced by ACTH in normal adrenocortical cells in culture

The effects of ACTH, its o-nitrophenyl sulfenyl derivative (NPS-ACTH) and dibutyryl cyclic AMP (dbc AMP) on the ultrastructural morphology of adrenocortical cells of adult rats in monolayer culture have been investigated. NPS-ACTH, which has previously been shown to stimulate steroidogenesis but not cAMP synthesis in adrenal cells, induced the same characteristic transformation of mitochondrial architecture as produced by ACTH or high concentrations of dbcAMP. All three agents caused the disappearance of electron-opaque granules present in the mitochondria of unstimulated cells. It was found that these granules could be extracted with EGTA (ethylene glycol-bis(beta-aminoethyl ether) N,N,N',N'-tetraacetate). These results are discussed in the light of the known importance of calcium ions in the actions of ACTH.     

Calculated molecular weight of proteins in high ionic strengths: contribution of the apparent isopotential specific volume.

Recent sedimentation equilibrium measurements of the molecular weight of tail muscle lactate dehydrogenase from the North American East Coast lobster Homarus americanus show that this enzyme does not dissociate in buffer with high ionic strength (1.2 m ammonium sulfate). However, the apparent isopotential volume φ₂′ increases significantly with increasing ionic strength of the solution. Consequently, molecular weight estimates for proteins using an assumed apparent specific volume equal to that in low salt concentration solutions may lead to erroneously low values under experimental conditions of high ionic strength.     

Mice with Spontaneous Mammary Tumors Develop Type-Specific Neutralizing and Cytotoxic Antibodies Against the Mouse Mammary Tumor Virus Envelope Protein gp52

Sera from C3H mammary tumor-bearing mice contain cytotoxic antibodies for mouse mammary tumor virus (MMTV)-producing cells, based on (51)Cr release in a complement-dependent serum cytotoxicity assay. The cytotoxic antibodies could be absorbed by purified C3H MMTV gp52 and C3H MMTV-infected cat cells (C3H [MMTV] CrFK) containing cell surface MMTV gp52. However, purified MMTV p27 and uninfected CrFK cat cells were negative. Absorption of the sera with GR (MMTV) CrFK cells also removed all of the cytotoxicity, whereas absorption with RIII (MMTV) CrFK cells was negative, even though all three infected cat cells contained equivalent amounts of gp52. The same C3H cytotoxic sera also neutralized the focus-forming capacity of a C3H MMTV pseudotype of Kirsten sarcoma virus containing MMTV gp52. In contrast, sera from mammary tumor-bearing GR and RIII mice did not neutralize the pseudotype. Furthermore, neutralization could be achieved only by anti-gp52 but not by anti-gp36, -p27, -p14, or -p10 C3H MMTV sera. The gp52's of C3H, GR, and RIII MMTV could also be distinguished by using a type-specific competition radioimmunoassay employing (125)I-gp52 of C3H MMTV and a hyperimmune rabbit anti-C3H MMTV serum. To demonstrate these differences directly, we studied the primary structure of gp52 on the surface of the C3H, GR, and RIII (MMTV) CrFK cells. Two-dimensional tryptic peptide maps of the cell surface lactoper-oxidase-catalyzed iodinated gp52's revealed a greater number of peptides common to the gp52's of C3H and GR MMTVs than to RIII MMTV gp52. These results demonstrate that gp52 is a major target antigen for both cytotoxic and neutralizing antibodies, that the cell surface and virion-associated gp52's of C3H, GR, and RIII MMTV contain both group- and type-specific determinants, and that C3H and GR MMTV gp52's are antigenically more related to each other than to RIII MMTV gp52. Furthermore, C3H mammary tumor-bearing mice develop type-specific antibodies capable of recognizing unique gp52 determinants and, therefore, are able to distinguish the gp52 of C3H MMTV from the gp52's of GR and RIII MMTV.     

湖北石松目植物的研究

石松目植物是蕨类植物中经济价值较高的一个类群,除孢子粉供铸造工业使用外,大部份种类供药用,有的种类为酸性土的指示植物。湖北石松种类比较丰富,历年来植物学工作者们在我省采集了大量标本,并对民间使用情况进行过调查,积累了不少有用     

Potentiation by calcium ions of the antithrombin III inhibition of thrombin

Calcium ions potentiated heparin-modulated antithrombin III inhibition of amidolysis catalysed by thrombin. Potentiation by calcium ions of heparin-independent antithrombin III inhibition of thrombin activity appeared to contribute to this effect. These results suggest a complex modulatory role for calcium ions in proteinase-catalysed reactions influenced by anti-proteinases and glycosaminoglycans.     

Thyroid lysosomes: the stability of the lysosomal membrane

To determine the integrity of lysosomes during their isolation from rat thyroid glands and their subsequent incubation at 37 degrees C, the sedimentability of lysosomal acid phosphatase and thyroglobulin (amount of undisrupted lysosomes) and the latency of sedimentable acid phosphatase (permeability of undisrupted lysosomes) were measured concomitantly. The following results were obtained: (a) During isolation of lysosomes in 0.25 M sucrose medium, mild homogenization of thyroid tissue or cholesterol addition did not modify the amount of undisrupted lysosomes but reduced their permeability. Homogenization in 0.5 M sucrose decreased both the amount and the permeability of undisrupted lysosomes. It also reduced their content of recently iodinated thyroglobulin (Tg). Cholesterol addition had no effect in 0.5 M sucrose medium. (b) During incubations at 37 degrees C of lysosomes, the amount of undisrupted lysosomes decreased progressively while their permeability increased. According to the incubation pH, the permeability of lysosomes prepared in 0.25 M sucrose was either more (pH 8) or less (pH 6) extensively increased than that of lysosomes prepared in 0.5 M sucrose. From these results, we concluded: (a) that isolation and incubation of the thyroid lysosomal fraction induce increased permeability of lysosomes prior to their complete disruption: (b) that recently formed lysosomes (high content of recently iodinated Tg) and aged lysosomes (low content of recently iodinated Tg) differ significantly. Recently formed lysosomes are more permeable, are stabilized by cholesterol and are more extensively disrupted in 0.5 M sucrose medium. During incubations, the permeabilities of these two classes of lysosomes are also differently affected by external pH.     

Effects of serotonin1-like receptor agonists on autonomic neurotransmission.

Serotonin1A receptor agonists, 8-hydroxy-2-(di-n-propylamino)tetralin and 10-methyl-11-hydroxyaporphine, inhibited electrical stimulation-induced contraction of the guinea-pig ileum. These agonists also inhibited the pressor and tachycardiac responses to low frequency (0.25 Hz) but not to high frequency (2.0 Hz) electrical stimulation of the sympathetic nervous system in pithed rats. Serotonin1B receptor agonist RU 24969 inhibited pressor and tachycardiac responses to both low and high frequencies of stimulation in pithed rats. In the cat nictitating membrane, serotonin1A receptor agonists did not alter contractions elicited by electrical stimulation (0.1-3.0 Hz). Serotonin not only contracted the cat nictitating membrane but also facilitated contractile responses to low frequency (0.1-1.0 Hz) stimulation. The contractile effect of serotonin in the cat nictitating membrane was blunted by bretylium, methysergide, and ketanserin, but not by metoclopramide. The facilitatory effect of serotonin was antagonized by methysergide, but not by ketanserin, pindolol, propranolol, or metoclopramide. These results suggest that serotonin1A receptors modulate autonomic neurotransmission in the guinea-pig ileum and pithed rats, but not in the cat nictitating membrane. Serotonin contracts the cat nictitating mebrane via serotonin2 subtypes, while facilitating stimulated contractile responses through the serotonin1-like receptors.