Sympathetic outflow response to muscle during vestibular stimulation in humans

To observe the effects of caloric vestibular stimulation on muscle sympathetic nerve activity (MSNA) in humans, 14 healthy volunteers were monitored in a supine position by electrocardiogram (ECG), blood pressure (BP), electro-oculogram (EOG). MSNA was monitored by a double recording technique of microneurography from the bilateral tibial nerves. Caloric vestibular stimulation was loaded by injecting 50 ml 44 degrees C warm water and 50 ml 10 degrees C cold water alternately into the external meatus for 1 min. Nystagmus was evoked in all cases by cold stimulation and in some cases by hot stimulation. The nystagmus evoked by cold stimulation was more intense than that by hot stimulation. MSNA was enhanced by either cold or hot stimulation; however, the enhancement mode differed between cold and hot stimulation. Cold stimulation evoked two peaks of MSNA while hot stimulation elicited only one peak. The first peak (404.5 +/- 115.4% with control value set at 100%, mean +/- SE) was estimated to be caused by cold stimulation on the skin of the external meatus while the second peak (379.2 +/- 65.3%) seemed to be the result of vestibular stimulation. With hot stimulation, the response peak of MSNA was 243.3 +/- 28.1%. In general, MSNA was enhanced after vestibular stimulation with MSNA increases was proportional to the stimulated level of the vestibular system.

V alpha 14+ NK T cells: a novel lymphoid cell lineage with regulatory function

A novel lymphoid lineage, NK T cells, was recently found. The NK T cells are the major population in the periphery comprising 5% of splenic T cells and 40% of bone marrow T cells. They express a unique TCR composed of invariant V alpha 14J alpha 281 and V beta 8.2 together with NK receptor (NKRPI). Surprisingly, the invariant V alpha 14+ TCR is exclusively expressed on NK T cells but not on conventional T cells. As the selective decrease in V alpha 14+ NK T cell population in the periphery is tightly correlated with autoimmune disease development, V alpha 14+ NK T cells control development of autoimmune diseases. We also found that V alpha 14 TCR gene rearrangement and transcripts were detected at an early embryogenesis (d9.5) before the thymus formation. Therefore NK T cells are in the distinct category from conventional T cells. The target of NK T cells is found to be CD1 (class 1b, monomorphic class I MHC-like molecule) present on bone marrow-derived cells and is killed by Fas-FasL interaction or perforin-mediated mechanisms. These results indicate that NK T cells consist of an immunoregulatory system different from defense system in terms of homogeneous repertoire, extrathymic development in early stage of gestation, and their regulatory functional role.

Fatal haemorrhage and incomplete block to embryogenesis in mice lacking coagulation factor V

Coagulation factor V is a critical cofactor for the activation of prothrombin to thrombin, the penultimate step in the generation of a fibrin blood clot. Genetic deficiency of factor V results in a congenital bleeding disorder (parahaemophilia), whereas inheritance of a mutation rendering factor V resistant to inactivation is an important risk factor for thrombosis. We report here that approximately half of homozygous embryos deficient in factor V (Fv-/-), which have been generated by gene targeting, die at embryonic day (E) 9-10, possibly as a result of an abnormality in the yolk-sac vasculature. The remaining Fv-/- mice progress normally to term, but die from massive haemorrhage within 2 hours of birth. Considered together with the milder phenotypes generally associated with deficiencies of other clotting factors, our findings demonstrate the primary role of the common coagulation pathway and the absolute requirement for functional factor V for prothrombinase activity. They also provide direct evidence for the existence of other critical haemostatic functions for thrombin in addition to fibrin clot formation, and identify a previously unrecognized role for the coagulation system in early mammalian development.

Essential requirement of an invariant V alpha 14 T cell antigen receptor expression in the development of natural killer T cells

NK1.1+ T [natural killer (NK) T] cells express an invariant T cell antigen receptor alpha chain (TCR alpha) encoded by V alpha 14 and J alpha 281 segments in association with a limited number of V betas, predominantly V beta 8.2. Expression of the invariant V alpha 14/J alpha 281, but not V alpha 1, TCR in transgenic mice lacking endogenous TCR alpha expression blocks the development of conventional T alpha beta cells and leads to the preferential development of V alpha 14 NK T cells, suggesting a prerequisite role of invariant V alpha 14 TCR in NK T cell development. In V beta 8.2 but not B beta 3 transgenic mice, two NK T cells with different CD3 epsilon expressions, CD3 epsilon(dim) and CD3 epsilon(high), can be identified. CD3 epsilon(high) NK T cells express surface V alpha 14/V beta 8 TCR, indicating a mature cell type, whereas CD3 epsilon(dim) NK T cells express V beta 8 without V alpha 14 TCR and no significant CD3 epsilon expression (CD3 epsilon(dim)) on the cell surface. However, the latter are positive for recombination activating gene (RAG-1 and RAG-2) mRNA, which are only expressed in the precursor or immature T cell lineage, and also possess CD3 epsilon mRNA in their cytoplasm, suggesting that CD3 epsilon(dim) NK T cells are the precursor of V alpha 14 NK T cells.

[Interventional treatment for partial stenosis or occlusion type of Budd-Chiari syndrome]

It is difficult to deal with interventional management of partial stenosis or occlusion type of Budd-chiari syndrome and manage the hepatic veins associated with inferior vena cave occlusion. Puncture, PTA and vascular stent plant were used to treat 12 patients with partial stenosis or occlusion of Budd-chiari syndrome. The procedures were successful. Either the symptoms or signs disappeared or relieved after operation. No severe side effects occurred. Follow-up for 1.5 through 26 months (average 8.5 months) revealed that the early or middle results were gratifying. There may be danger during operation, but perfect skills and adequate clinical anatomic knowledge help avoid severe side effects.

Lack of plasminogen activator inhibitor-1 effect in a transgenic mouse model of metastatic melanoma

Tumor cell invasion and metastasis is a complex, multistep process that is postulated to require degradation of extracellular matrix at several steps. Urokinase-type plasminogen activator (uPA) is expressed on the cell surface of B16 murine melanoma cells and is thought to contribute to the pericellular proteolysis necessary for tumor cell migration. In vitro modification of B16 melanoma cell surface uPA activity has been shown to alter the invasive and metastatic potential of these murine melanoma cells in vivo. Plasminogen activator inhibitor-1 (PAI-1), a rapid inhibitor of both uPA and tissue-type plasminogen activator (tPA) is the major physiologic regulator of plasminogen activator activity. To test the role of host PAI-1 in the invasive and metastatic capacity of B16 melanoma cells we analyzed local tumor growth and pulmonary metastasis in transgenic mice engineered to overexpress murine PAI-1 in multiple tissues including lung, and in mice completely deficient in PAI-1. No significant difference in the number of pulmonary metastases was observed after intravenous inoculation of tumor cells into PAI-1-overexpressing and PAI-1-deficient mice when compared with wild-type controls. Similarly, in a spontaneous metastasis model, PAI-1-overexpressing and PAI-1-deficient mice demonstrated no difference in primary tumor size or overall survival. These data demonstrate that wide variations of host PAI-1 expression, from complete absence to marked overexpression, does not significantly influence the metastatic potential of B16 melanoma cells in a murine model.

[The epidemiological and clinical features of 208 patients with trichinosis]

In order to know the epidemiological and clinical features of trichinosis, the data of 208 patients with trichinosis from 1992 to 1994 were analysed. The results showed that these patients came from 11 districts, and acquired the infection mainly by tasting the raw pork filling for dumplings or ingesting instant-boiled pork or mutton. The incidence of trichinosis is high in winter. Young and middle-aged workers and cadres constituted the majority of the patients and the infection was more common in the males than in females. The main clinical manifestations of trichinosis were prolonged fever, general myalgia, muscle weekness and eosinophilia. Most of the patients had no gastrointestinal symptoms and skin eruption. Eyelid edema was only seen in the early stage. Serological tests were significant value in the diagnosis of trichinosis. The key measures to prevent trichinosis were that meat inspection should be strictly carried out and bad eating habit changed.

Exercise echocardiography: feasibility and value for detection of coronary artery disease

OBJECTIVE

To evaluate the feasibility and accuracy of exercise echocardiography (Ex-Echo) for the diagnosis of coronary artery disease (CAD) based on coronary angiography (CA).

PATIENTS AND METHODS

Forty-seven patients were found to have CAD and examined by upright exercise electrocardiography (Ex-ECG) on a treadmill within two weeks of CA. Before and immediately after exercise, the patients lay on a bed beside the treadmill in the left lateral position and parasternal long and short axis and apical two and four chamber views of the heart were acquired. Pre- and post-echocardiograms were analysed in a side-by-side multiple screen format on the imaging view and hypodynamic wall motion of the left ventricle after exercise was defined as Ex-Echo positive. The sensitivity, specificity and predictive accuracy of Ex-Echo and Ex-ECG were calculated on the basis of CA data.

RESULTS

Satisfactory echocardiograms were recorded in 46 patients after exercise. The success rate was 97.8%. Compared with Ex-ECG, Ex-Echo was more sensitive (87.5% vs 62.5%, P < 0.05), specific (92.8% vs 60.0%, P < 0.05) and accurate (89.4% vs 61.7%, P < 0.01). The concord of determining the number of diseased vessels between coronary angiography and Ex-Echo was 90.9% in single vessel disease and 45.0% in multiple vessel disease. Wall motion scoring index, however, was higher in multiple than in single vessel CAD.

CONCLUSIONS

Ex-Echo test is feasible and accurate in detecting CAD and wall motion scoring index is probably useful in distinguishing multiple from single vessel CAD.

[Deletion and down-regulation of mts1/p16 gene in human gastric cancer]

Deletion of mts1/p16 gene was frequently detected in many human tumor cell lines. However, whether alteration of the p16 gene was involved in human gastric carcinogenesis, it is not clear. In order to determine the incidence and correlation of the p16 gene deletion with human gastric cancer, we performed analyses of PCR, Southern and Northern blotting on 85 fresh tumor specimens and 5 tumor cell lines from gastric cancer patients. Homozygous deletion was observed in 1 cell line and down-regulation of expression was observed in 3. High rate of gene deletion was detected by PCR in 14 of 85 fresh tumor tissues. Gene deletion was confirmed by Southern blot analysis with p16 cDNA probe in 6 out of 26 tumor specimens examined.

Presence of antilamin antibodies in sera of patients with systemic lupus erythematosus

In this study, we characterized specifically-stained sera from patients with systemic lupus erythematosus (SLE) which had been shown to display the homogeneous or peripheral region of nuclei by indirect immunofluorescence (IIF). By western blotting, we demonstrated that in some cases there was a correlation between the peripheral or homogenous. IIF staining of nuclei by sera from patients with SLE and the presence of autoantibodies to lamins. Here we first report the presence of 2.2% anti-lamin autoantibodies in the sera among the 174 patients with SLE in China.

Melanoma and vitiligo are associated with antibody responses to similar antigens on pigment cells

BACKGROUND AND DESIGN

Several clinical observations suggest that there is a link between vitiligo and melanoma. We examined whether an immune response to similar antigens on pigment cells could account for this association. We tested 30 patients with melanoma, 29 patients with vitiligo, and 28 patients with unrelated conditions for antibodies to human melanocyte antigens using an immunoprecipitation sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis assay.

RESULTS

Antibodies to melanocytes were present in 24 (80%) patients from the melanoma group, 24 (83%) patients from the vitiligo group, and in two (7%) patients from the control group. The antibodies in patients with melanoma or vitiligo were directed to similar antigens with molecular weights of approximately 40 to 45, 75, and 90 kd. The frequency of antibody responses to each of these antigens was similar in both diseases. By sequential immunodepletion, the antigens defined by antibodies in both diseases were similar. These antigens were also expressed on melanoma cells.

CONCLUSIONS

Most patients with melanoma or with vitiligo develop antibodies to similar antigens that are present both on melanocytes and on melanoma cells. These findings support the hypothesis that the clinical link between the two diseases results from immune responses to antigens shared by normal and malignant pigment cells.

Antimelanoma antibodies in swine with spontaneously regressing melanoma

Sinclair swine provide a unique model for studying mechanisms of tumor regression because they are born with melanomas that spontaneously regress approximately 10 weeks after birth. To examine whether an antitumor immune response is present in these animals, and, if so, to study its relation to tumor regression, 38 sera specimens collected at different times from 13 swine born with melanomas were tested for melanoma antibodies by immunoprecipitation and SDS-PAGE analysis of 125I labelled swine melanoma macromolecules. Antibodies to melanoma were present in 13 (100%) of the swine versus 1 of 3 control swine. The antibodies were directed to antigens of approximately 45, 68-75, or 100 kDa. These antigens were also expressed on human melanomas and normal melanocytes but on only one of five unrelated tumors. The incidence and level of these antibodies increased with time. Antibodies to the 45, 68-75, and 100 kDa antigens were present in 36%, 55%, and 9%, respectively, of sera collected prior to 7 weeks of age, but in 80%, 100%, and 37% of sera collected between 7 and 20 weeks (P < 0.05). The rise in melanoma antibodies usually preceded or appeared together with tumor regression and loss of pigmentation. These findings indicate that Sinclair swine with melanomas have antibodies to antigens preferentially expressed on pigment cells, and support the hypothesis that the regression phenomenon and the vitiligo-like skin depigmentation result from immune responses to common antigens shared by normal and malignant swine pigment cells.

Characterization of vitiligo antigens

Patients with vitiligo have circulating antibodies directed in part to pigment cell antigens with MWs of approximately 90, 75, and 40-45 kDs. These antigens are denominated VIT 90, VIT 75, and VIT 40, respectively. To further characterize these "vitiligo" antigens, we examined their relation to antigens defined by a panel of 25 monoclonal antibodies (moab) to pigment cell antigens. We found by immunoprecipitation and SDS-PAGE analysis of 125I labelled, detergent soluble, human melanocyte macromolecules, that 24 (83%) of 29 patients with vitiligo had antibodies to one or more vitiligo antigens vs. 2 (7%) of 28 control individuals. Seventeen of the 25 moabs did not react with any labelled antigen in the same lysate. Of the remaining eight moabs, only four precipitated an antigen that co-migrated with one of the vitiligo antigens. Moab TA99, HMSA-5, and TMH-1 (all directed to the 75 kD tyrosinase-related protein [TRP1]) co-migrated with VIT 75. Moab W6/32 (directed to class I HLA antigen) co-migrated with VIT 40. Immunodepletion studies with vitiligo antibodies selectively depleted the antigen defined by W6/32 but not the antigen defined by TA99 and HMSA-5, indicating that VIT 75 was not the 75 kD tyrosinase-related protein. The vitiligo antigens were easily labelled by the lactoperoxidase technique but poorly labelled with 35S-methionine, suggesting they are expressed on the cell surface. These studies indicate that VIT 90 and VIT 75 differ from antigens defined by currently available moabs to pigment cell antigens. VIT 40 appears to share a cross-reactive epitope, or be tightly bound to, class I HLA antigen.

Improved survival of patients with melanoma with an antibody response to immunization to a polyvalent melanoma vaccine

BACKGROUND

Melanoma vaccine treatment appears to slow the progression of melanoma in some patients, particularly in patients in whom it stimulates cellular antimelanoma immune responses. The relationship of vaccine-induced antibody responses to clinical outcome is less clear. The purpose of this study was to investigate the clinical relevance of antibody responses to melanoma vaccine immunization.

METHODS

Eighty-two evaluable patients with surgically resected American Joint Committee on Cancer Stage III malignant melanoma were immunized to a partially purified, polyvalent, melanoma antigen vaccine. Antimelanoma antibodies were measured by immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis before vaccine treatment and 1 week after the fourth immunization.

RESULTS

Vaccine treatment induced or augmented antibody responses to melanoma in 32 (39%) of the patients. The antibodies were directed to one or more antigens of 38-43, 75, 110, 150 and/or 210 kDs, which previously have been shown to be expressed preferentially in cultured human melanoma cells. The median disease free survival of patients with a vaccine-induced antibody response to one or more of these antigens was 5.4 years compared with 1.4 years for nonresponders (P = 0.06), and 5-year overall survival was 71% compared with 44%, respectively (P = < 0.01). As determined by Cox multivariate analysis, the difference in overall survival was independent of disease severity or of immunologic competence as evaluated by ability to be sensitized to dinitrochlorobenzene. The difference in survival between antibody responders and nonresponders improved with time.

CONCLUSIONS

The antibody response to vaccine treatment is an immune marker of vaccine activity that appears to be predictive of a later reduction in the recurrence of melanoma and is unrelated to the vaccine's ability to induce cellular immune responses. This finding suggests that vaccine treatment may be effective in slowing the progression of melanoma in some patients and that the protective effect is mediated partly by vaccine-induced antimelanoma antibodies.

Gating of IsK expressed in Xenopus oocytes depends on the amount of mRNA injected

IsK is a K+ channel of the delayed rectifier type widely distributed throughout both excitable and nonexcitable cells. Its structure is different from other cloned K+ channels and molecular details of its gating remain obscure. Here we show that the activation kinetics of IsK expressed in Xenopus oocytes depend upon the amount of its mRNA injected, with larger amounts resulting in slower activation kinetics with a longer initial delay during activation. Similar changes in activation kinetics occur with time after a single injection of IsK mRNA. We present two kinetic schemes which illustrate how our experimental results could arise. Both imply an interaction among individual channel proteins during IsK activation. The dependence of channel gating on mRNA concentration provides a novel mechanism for long term regulation of ion current kinetics.

Studies on atrophic change of soleus muscle and its countermeasures in suspended rat

In the environment of microgravity, the disused atrophy of skeletal muscle, especially leg's muscle, would occur. The three purposes of this study were: 1. To observe the dynamic changes of disused atrophy of skeletal muscle under simulated weightlessness; 2. To approach the mechanism of disused atrophy of muscle; 3. To approach the countermeasures for reducing the degree of atrophy of muscle.

Effect of CL-316,243, a thermogenic beta 3-agonist, on energy balance and brown and white adipose tissues in rats

The objective was to assess the effect of a new, highly selective beta 3-adrenergic agonist, CL-316,243 (CL) (J. D. Bloom, M. D. Dutia, B. D. Johnson, A. Wissner, M. G. Burns, E. E. Largis, J. A. Dolan, and T. H. Claus., J. Med. Chem. 35: 3081, 1992), on energy balance and brown and white adipose tissues (BAT and WAT, respectively) in young rats eating a high-fat diet to induce obesity. Chronic treatment with CL increased body temperature and 24-h energy expenditure, mainly by increasing resting metabolic rate. Food intake was not altered but carcass fat was reduced. Interscapular BAT was markedly hypertrophied, with three- to fourfold increases in the content of uncoupling protein (UCP) and cytochrome oxidase. Quantitative immunoelectron microscopy of interscapular BAT of CL-treated rats showed smaller mitochondria with an unchanged total amount of UCP per mitochondrion. The relative frequency of the four major cell types in BAT (mature brown adipocytes, preadipocytes, interstitial cells, endothelial cells) was not altered. The CL-induced hypertrophy differed from that induced by chronic stimulation by endogenous norepinephrine (as in cold-adaptation) in absence of hyperplasia (there was a slightly reduced DNA content), absence of an increase in the thyroxine (T4) 5'-deiodinase activity, and absence of a selective increase in UCP concentration. WAT depots weighed less and had fewer cells (lower DNA content) in the CL-treated rats. Some multilocular adipocytes appeared in these normally almost exclusively unilocular WAT depots (mesenteric, inguinal, epididymal, retroperitoneal). We conclude that CL not only promotes BAT mitochondrial proliferation and thermogenesis and overall energy expenditure and leanness, but also retards the development of WAT hyperplasia during the early stage of diet-induced obesity.

The change of melanocyte cytotoxicity after systemic steroid treatment in vitiligo patients

Although there is evidence of a strong association between antimelanocyte autoantibodies and vitiligo, the etiology of vitiligo is still unclear. To elucidate the biological significance of antimelanocyte autoantibodies in vitiligo, we measured the percent cytotoxicity of melanocyte mediated by autoantibody and complement in normal controls (n = 31) and in the patients with active, progressive vitiligo (n = 37). Significant differences in percent cytotoxicity of melanocyte were seen between the control and vitiligo groups (P = 0.0001). There were no significant differences in the percent cytotoxicity of melanocyte between the patients (n = 24) with more than 1 year duration and those (n = 13) with less than 1 year duration. The change of percent cytotoxicity between pre- and post-treatment groups (n = 29) with systemic steroid showed significant differences (P = 0.0243). These findings support the hypothesis that a decrease in the antibody-mediated cytotoxicity against melanocytes may play a role in the improvement of vitiliginous lesions after systemic steroid treatment.

[Studies on the pleomorphism of trachoma inclusion]

A series of trachoma inclusion color photograph is taken from the conjunctival smears of 48 trachoma cases. These smears were Giemsa-stained and stored in the slide-boxes for more than 30 years with no distinct changes in color. A description is given to the Pleomorphism of trachoma inclusion and its relation to the host cells. According to the gradual morphological changes of Chlamydia trachomatis multiplied in the infected cells, a 5-staged classification for trachoma inclusions is provided which may be benefit to understanding the pleomorphism of the trachoma inclusion and clinical laboratory diagnosis.

ATPase activity of TyrR, a transcriptional regulatory protein for sigma 70 RNA polymerase

The TyrR protein of Escherichia coli is the chief transcriptional regulator of several genes essential for aromatic amino acid biosynthesis and transport. It was established in previous studies that this protein binds ATP, that the TyrR.ATP complex has enhanced affinity for tyrosine, and that the susceptibility of the TyrR protein to hydrolysis by trypsin is altered by ATP. Here we show that the TyrR protein has ATPase activity, which is stimulated by tyrosine. In this respect the TyrR protein resembles the transcriptional activator NtrC. The NtrC protein contains an internal polypeptide segment, 220 amino acid residues in length, with a high degree of identity to the TyrR protein, that contains the presumptive ATPase catalytic center.

Follow-up of asymptomatic myocardial ischemia in patients with diabetes mellitus

Early detection of asymptomatic myocardial ischemia in patients with diabetes mellitus (DM) is very important for the prevention of painless myocardial infarction. The purpose of this study is to explore the clinical significance of asymptomatic transient ST changes in ECG in patients with DM and to further clarify the relation between asymptomatic myocardial ischemia and myocardial infarction in DM.

Cytolytic antibodies to melanocytes in vitiligo

Patients with vitiligo have been found to have circulating antibodies to pigment cells. To evaluate the functional activity of these antibodies, a highly sensitive europium release assay was used to compare complement-mediated cytolysis of human melanocytes by sera of 56 patients with vitiligo (20 with active disease, 25 with inactive disease, 11 with unidentified disease activity) and 47 control individuals. Significant melanocyte lysis was mediated by 32 (57%) of the patients with vitiligo but by only three (6%) of the control sera (p < 0.001), and by 17 (85%) of 20 patients with active vitiligo versus 11 (44%) of 25 patients with inactive disease (p < 0.025). Mean melanocyte lysis by vitiligo sera was 24% versus 6% by control sera (p < 0.0001). A subset of 12 vitiligo sera with high titers of cytolytic antibodies to melanocytes (34% mean cytolysis) reacted minimally (< 2% mean cytolysis) to a panel of control cells that included human and murine melanomas, human fibroblasts, lung carcinoma, and rhabdomyosarcoma. These findings indicate that antibodies present in patients with vitiligo have the functional ability to selectively kill melanocytes and are more common in active disease. These observations support, but do not prove, the hypothesis that vitiligo is an autoimmune disease and that anti-pigment cell antibodies have a role in inducing the disease.

The TyrR protein of Escherichia coli, analysis by limited proteolysis of domain structure and ligand-mediated conformational changes

The TyrR protein of Escherichia coli K12 is a homodimer containing 513 amino acids/subunit. This protein is important in the transcriptional regulation of several genes whose protein products catalyze steps in aromatic amino acid biosynthesis or transport. Methods were developed for efficiently purifying the TyrR protein to apparent homogeneity. We analyzed the pattern of cleavage of the TyrR protein by trypsin, either in the absence of ligands or in the presence of saturating levels of L-tyrosine, ATP, or poly(dI-dC). At low (1:200 ratio by weight) trypsin levels, in the absence of ligands, two major digestion products accumulated. These were polypeptides of 22 and 31 kDa, shown to contain amino acid residues 1-190 and 191-467, respectively. The pattern of trypsin cleavage was unaffected by tyrosine. In the presence of ATP, an intermediate species of 53 kDa, probably containing amino acid residues 1-467, was observed. The kinetics of appearance of the 53-kDa species were consistent with a role for ATP in accelerating the hydrolysis of the R467-F468 peptide bond. The 53-kDa polypeptide underwent further tryptic hydrolysis to yield fragments of 22 and 31 kDa. When both tyrosine and ATP were present, the rate of formation of the 22- and 31-kDa fragments was more rapid than in the absence of these ligands. It appears that when both ligands are bound, the rates of hydrolysis of peptide bonds R190-Q191 and R467-F468 are both enhanced. Additional limited proteolysis experiments suggested that polypeptide segment 191-467 contains ATP binding site(s), and that the rate of cleavage of peptide bonds R190-Q191 and R467-F468 is altered when the TyrR protein interacts with poly(dI-dC), an analog of target DNA. Our results reveal the presence of two major structural domains within the TyrR protein. The first domain (amino acid residues 1-190) is extremely resistant to hydrolysis by trypsin. The second domain (residues 191-467), which is likely to contain ATP-binding site(s), is homologous to several other transcriptional activators specific for promoters responsive to the sigma 54 form of RNA polymerase. The remainder of the TyrR protein (residues 468-513) contains the operator recognition elements, probably arranged in the form of a helix-turn-helix motif. This polypeptide segment was not detected as a discrete tryptic hydrolysis product.

A mutational analysis of the structural basis for transcriptional activation and monomer-monomer interaction in the TyrR system of Escherichia coli K-12

In response to the binding of tyrosine or phenylalanine, the TyrR protein (513 amino acids) activates certain promoters and represses others. In a previous study (J. Cui and R. L. Somerville, J. Bacteriol. 175:303-306, 1993), it was shown that promoter activation was selectively abolished in mutant proteins lacking amino acid residues 2 to 9. An additional series of constructs that encoded mutant TyrR proteins having deletions or point mutations near the N terminus were analyzed. Residues Arg-2 and Leu-3 were shown to be critical for the activation of the mtr promoter. In confirmation of previous findings, none of the activation-defective mutant TyrR proteins had lost significant repression function. The TyrR protein was shown by chemical cross-linking to be dimeric. The polypeptide segments critical for dimer formation in vivo were identified by evaluating the negative dominance phenotypes of a series of mutant proteins, all defective in DNA binding, lacking progressively greater numbers of amino acid residues from either the N terminus or the C terminus. Amino acid residues 194 to 438 were found to contain all of the essential dimerization determinants.

Mutational uncoupling of the transcriptional activation function of the TyrR protein of Escherichia coli K-12 from the repression function

The tyrosine repressor (TyrR) protein of Escherichia coli can function either as a transcriptional enhancer or as a repressor. The structural basis for these opposite effects was analyzed in specific tyrR deletion mutants constructed in vitro. The functional behavior of the mutant TyrR proteins was evaluated in vivo by using single-copy lacZ reporter systems based on the mtr promoter (10-fold activation by wild-type TyrR protein, mediated by phenylalanine or tyrosine) or the aroF promoter (over 20-fold repression by wild-type TyrR protein, mediated by tyrosine). A mutant TyrR protein lacking amino acids 2 to 9 was completely devoid of transcriptional activation function. Five additional mutant TyrR proteins lacking progressively greater numbers of N-terminal amino acids were likewise activation defective. The mutant TyrR proteins lacking amino acid residues 2 to 9 or 2 to 19 were essentially identical to the wild-type TyrR protein in their ability to repress the aroF promoter. Three other TyrR mutant proteins, lacking up to 143 amino acid residues from the N-terminal end of the protein, retained the ability to repress the aroF promoter, to different extents, in a tyrosine-dependent manner.

Expression and characterization of a canine hippocampal inwardly rectifying K+ current in Xenopus oocytes

1. An inwardly rectifying potassium current expressed in Xenopus laevis oocytes injected with canine hippocampal poly(A)+ RNA was investigated with the two-microelectrode voltage clamp technique. 2. Xenopus oocytes injected with canine hippocampal poly(A)+ RNA expressed a current activated by hyperpolarization. This current contained an instantaneous and a time-dependent component. Both components were inwardly rectifying and could be blocked by extracellular Cs+ or Ba2+. 3. The expressed current was carried mainly by K+. Its reversal potential measured in different [K+]os could be fitted by the Nernst equation with a slope of -50.7 per tenfold change in [K+]o. Extracellular Cl- and Na+ made minimal contributions to the current. 4. The activation of the expressed current depended on both voltage and [K+]o. Activation started near EK and the activation curve shifted along the voltage axis in parallel with EK when [K+]o was altered. 5. The activation time constants of the expressed current also depended on both voltage and [K+]o. The voltage dependence of the time constants was bell-shaped and the peak value was at a potential 30-50 mV more negative than EK. The voltage dependence of the time constants shifted along the voltage axis when EK was changed. 6. The poly(A)+ RNA extracted from canine hippocampus was fractionated in a 10-31% linear sucrose gradient. The size of the mRNA required to express the inwardly rectifying current was estimated to be around 4 kb. 7. In conclusion, the expressed current is an inwardly rectifying potassium current. The canine hippocampal mRNA should be an excellent source for expression-cloning of the inward rectifier channel.

Physical map location and transcriptional orientation of the tyrR gene of Escherichia coli K-12

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Rapid but transient atrophy of brown adipose tissue in capsaicin-desensitized rats

Our previous studies showed atrophy of brown adipose tissue (BAT) in capsaicin-desensitized rats during the period 11-28 days after injections [Cui et al., Am. J. Physiol. 259 (Regulatory Integrative Comp. Physiol. 28): R324-R332, 1990]. The objective of the present studies was to assess the rapidity with which the atrophy occurred and the extent to which recovery had occurred by 8 wk. Rats, either vehicle-injected controls or capsaicin injected, were studied 1, 3, 14, 28, and 52 days after the last injection. BAT was markedly atrophied at 1 day, having less total protein, fewer mitochondria (less total cytochrome oxidase and total uncoupling protein), and fewer cells (less DNA). Atrophy persisted for up to 14 days but had largely disappeared by 28-52 days. A transient reduction in body weight gain and white epididymal adipose tissue weight had also reversed by 28-52 days. We suggest that the rapid atrophy of BAT after capsaicin desensitization is secondary to the loss of sensory neuropeptides in its sensory nerves, neuropeptides that either exert a trophic effect on synthesis of mitochondria or an inhibitory influence on processes that promote degradation of mitochondria. The retardation of the normal age-associated increase in DNA content of BAT in the capsaicin-desensitized rat suggests that sensory neuropeptides might also modulate cell proliferation.

Long-term decrease in body fat and in brown adipose tissue in capsaicin-desensitized rats

Previous studies showed that atrophy of brown adipose tissue (BAT) of capsaicin-desensitized rats occurs rapidly and persists for up to 28 days. The rats do not, however, become any more obese than control rats, despite the frequent association of atrophied BAT with obesity. The objective of the present study was to assess longer-term effects of capsaicin desensitization on BAT and on energy balance. Rats were studied at 2.5, 3.5, and 8 mo after treatment. Major effects at 8 mo, mostly seen to a lesser extent at 3.5 mo but not at 2.5 mo, were a marked reduction in body weight that was largely attributable to a reduction in body fat but also to some stunting of growth and an atrophy or lack of growth of BAT (reduced weight and content of protein, DNA, cytochrome oxidase, and uncoupling protein). Resting metabolic rates and food intake at 8 mo were reduced in proportion to the smaller body size. We suggest that the lack of trophic influence of sensory neuropeptides on BAT proposed previously may extend to other organs, including white adipose tissue, and contribute to the reduced adiposity and the smaller body size of capsaicin-desensitized rats.

An improved europium release assay for complement-mediated cytolysis

An improved assay for complement-mediated cytolysis is described. The target cells are labeled with europium complexed to diethylenetriaminopentaacetate (Eu-DTPA). Cytolysis caused by antibody plus complement leads to the release of the Eu-DTPA complex which is then formed into a highly fluorescent chelate by the addition of 2-naphthoyltrifluoroacetone (2-NTA). The amount of europium chelate formed--a measurement of cell death--is then quantified with a time-resolved fluorometer. The results of the assay are reproducible. Complement-mediated cytolysis when measured by europium release was five times more sensitive than when measured by conventional 51Cr release and three times than when measured by trypan blue exclusion. Because europium does not decay, target cells can be labelled in batches and stored frozen until use, which speeds and simplifies the assay. Thus, europium release assay is a simple and quantitative method to measure complement-mediated cytolysis which is sensitive and more rapid than conventional assays.

Identification of Pigment Cell Antigens Defined by Vitiligo Antibodies

Patients with vitiligo have circulating antibodies to pigment cells. To characterize this response further and to identify the antigens defined by vitiligo antibodies, sera of 23 patients with vitiligo and 22 patients with unrelated conditions were analyzed by immunoprecipitation and SDS-PAGE analysis of 125I-labeled cell antigens on pigment and control cells. Antibodies to pigment cell antigens were present in 18 (78%) of the patients with vitiligo but in only three (14%) of the control patients (p less than 0.05). The antibodies were directed to one or more antigens with molecular weight (MW) in kilodaltons (kD) of approximately 35, 40-45, 75, 90, or 150. The responses were most commonly directed to the 40-45-kD, 75-kD, and 90-kD antigens. Antibodies to these antigens were present in 74%, 57%, and 35% of vitiligo patients versus in 14%, 9%, and 0% of control individuals. The 35-kD and 90-kD antigens were preferentially expressed on human pigment cells, whereas the 40-45-, 75-, and 150-kD antigens were expressed on both pigment and control cells. These antigens were labeled by the lactoperoxidase technique, suggesting that they are cell surface antigens. These results confirm that antibodies to pigment cells are associated with vitiligo. These antibodies are directed to several cell surface antigens, some of which are preferentially expressed on pigment cells.

Relation between the incidence and level of pigment cell antibodies and disease activity in vitiligo

Patients with vitiligo often have antibodies to pigment cells. To examine whether there is a relation between the presence of such antibodies and disease activity, sera of 24 patients with vitiligo (10 with active and 14 with inactive disease) and 19 normal individuals were tested for antibodies to pigment cell surface antigens using a live cell enzyme-linked immunoabsorbent assay. IgG pigment cell antibodies were present in 80% (eight of 10) of patients with active vitiligo but in none of those with inactive disease or in normal individuals. The antibody level of patients with active vitiligo (mean binding index [BI] 3.3 +/- 0.59) was significantly higher than in patients with inactive disease (BI 0.96 +/- 0.04) or normal individuals (BI 1.0 +/- 0.04, p less than 0.001). Antibodies present in eight patients with high titers of pigment cell antibodies reacted to three of four pigment cells but to only one of six unrelated cells. These findings indicate that a correlation exists between the incidence and level of pigment cell antibodies and the activity of vitiligo, and support the hypothesis that vitiligo is an autoimmune disease mediated by an immune reaction to pigment cells.

Role of hair follicles in the repigmentation of vitiligo

Vitiligo is a common pigment disease that is difficult to treat. The mechanism of repigmentation is not known. We combined Dopa-Toluidine Blue complex stain, hair follicle split-Dopa stain, and hair follicle split-scanning electron microscope (SEM) to observe the changes of melanocytes in 23 normal, 24 vitiliginous, and 36 repigmented skin specimens. We found that only active (Dopa-positive) melanocytes existed in the epidermis of normal skin. There were some inactive (Dopa-negative) melanocytes in the outer root sheaths of normal hair follicles, which form the melanocyte reservoir in human skin. In the patients with vitiligo the active melanocytes in the epidermis were totally missing, whereas the inactive melanocytes in the outer root sheaths of hair follicles were not affected. Treatment stimulated the inactive melanocytes in the middle and/or lower parts of the outer root sheaths of hair follicles to divide, proliferate, and migrate upward along the surface of the outer root sheath to the nearby epidermis, where the melanocytes continued to migrate radially to form the pigmented island visible clinically in repigmented vitiligo lesions. During the migration to the epidermis, the melanocytes matured gradually from an inactive phase to an active condition. In conclusion, the existence of these inactive melanocytes provided the melanocyte sources for repigmentation of vitiligo.

[American ginseng compound liquor on retarding-aging process]

71 cases with age over sixty were randomly divided into treated group and control group, and observed by single-blind method. 36 cases were administered with American ginseng compound liquor as a treated group, 35 cases were administered with American ginseng liquor only as a control group. The total effective rates of the treated group and the control group on symptoms associated with aging were 88.89% and 68.57% respectively (P less than 0.05). The effective rates of the treated group for Kidney-Yang, Kidney-Qi and Kidney-Yin deficiencies were 85.71%, 100% and 87.50% respectively. The effective rates of the control group were 81.82%, 100% and 61.53% respectively. The above results indicated that the symptoms of Kidney-Yang deficiency in the treated group were improved much better than those of the control group (P less than 0.05). Obviously, SOD activity of erythrocyte and SOD/LPO ratio increased remarkably and serum content of LPO decreased significantly in both groups (P less than 0.001). In the treated group, the functional months of age (physiological age) decreased from 751.77 +/- 5.215 to 743.53 +/- 5.144, the effective rate was 68.57%. It showed that these two recipes both had the efficiency on prolonging the functional age (P less than 0.05).

Capsaicin desensitization induces atrophy of brown adipose tissue in rats

Interscapular brown adipose tissue (BAT) of capsaicin-desensitized (Cap-Des) rats is atrophied, having a lower wet weight, a reduced total protein content, and as little as 10% of the normal content of uncoupling protein (UCP). Because the mitochondrial concentration of UCP, relative to other mitochondrial proteins, is not altered in Cap-Des rats, it is concluded that most of the mitochondria of BAT of Cap-Des rats have been lost. Consistent with this interpretation is a reduction of almost 40% of the overall thermogenic response to infused norepinephrine by anesthetized Cap-Des rats. Feeding a palatable diet had a delayed thermogenic effect and no trophic effect on BAT of Cap-Des rats. Food selection and intake were normal in Cap-Des rats, and diet-induced weight gain was the same as in control rats. Exposure of Cap-Des rats to cold for 1 or 7 days exerted a normal thermogenic effect on BAT but a delayed trophic effect. The cold-induced increase in thyroxine 5'-deiodinase in BAT occurred normally. Cap-Des rats were hypothermic at 1 day but normothermic by 7 days of cold exposure. The concentration of thyroid hormones in their blood was normal. It is suggested that the depletion of sensory neuropeptides in BAT presumed to be brought about by Cap-Des results either in loss of a trophic influence on mitochondriogenesis in BAT or in lack of an inhibitory influence on mitochondrial breakdown in BAT and leads to atrophy of BAT in rats living at 26 degrees C and an impaired response to stimulation by diet.(ABSTRACT TRUNCATED AT 250 WORDS)

[Analgesic and antipyretic effects of cyproheptadine]

Cyproheptadine-HCl raised the pain thresholds during hot plat test and writhing test in mice and tail flick test in rats, strengthened the hypnotic action by subthreshold dosage of sodium pentobarbital and chloral hydrate. The ED50 were 4.4 (3.2-5.7) and 12.4 (8.4-18.2) mg/kg 30 min after ip cyproheptadine in mice and rats, respectively. The ED50 was 0.14 (0.12-0.18) mg/kg 90 min after icv cyproheptadine in mice. Cyproheptadine po 20, 40 mg/kg and ip 10, 20 mg/kg showed significant antipyretic effects on yeast-induced pyrexia in rats.