Sympathetic nerve response to microgravity induced by parabolic flight

The aim of this study was to clarify how muscle sympathetic nerve activity (MSNA) in humans, which plays an important role in blood pressure control against gravity, is altered under microgravity conditions. Subjects were seated in a jet aircraft with their legs extended. MSNA was recorded microneurographically from the tibial nerve of the sitting subjects with simultaneous monitoring of electrocardiogram, blood pressure, respiration, and intrathoracic blood volume during parabolic flights. In the Air Force training area, the aircraft made parabolas up to 10 times. At the entry to microgravity, intrathoracic blood volume increased, systemic blood pressure was elevated, and MSNA was suppressed. However, this MSNA suppression lasted only 10-15 sec, and then followed by an enhancement to the end of the parabolas. We conclude that MSNA is suppressed at the onset of microgravity during parabolic flight in response to loading of the cardiopulmonary volume receptor due to a cephalad body fluid shift. However, this MSNA suppression is transient during such dynamic gravitational changes as those induced by parabolic flight, probably modulated by arterial baroreceptors.

[A novel immune system]

We found a novel lymphoid cell lineage, V alpha 14 NKT cell, which is characterized by 1) the expression of both NK1.1 (NK receptor) and an invariant TCR encoded by V alpha 14 and J alpha 281 gene segments; 2) the expression of unusual phenotypes, such as NK1.1+, B220+, Mac-1+, HSA+, CD44+, CD45Rlow and MEL-14low; and 3) the extrathymic development: V alpha 14 NKT cells appear at d9.5 of gestation before thymus development. Moreover, the deletion of the invariant V alpha 14 TCR gene expression caused the lack of NKT cells in vivo, while transgene of the invariant V alpha 14 V beta 8 TCR in the RAG-deficient background resulted in the generation of only V alpha 14 NKT cells without other lymphoid cells. These results indicate the essential requirement of invariant V alpha 14 TCR for the development of NKT cells. Recent studies clearly show that V alpha 14 NKT cells, but not NK cells or T cells are the primary target of IL-12 in the IL-12-mediated tumor rejection.

CD1d-restricted and TCR-mediated activation of valpha14 NKT cells by glycosylceramides

Natural killer T (NKT) lymphocytes express an invariant T cell antigen receptor (TCR) encoded by the Valpha14 and Jalpha281 gene segments. A glycosylceramide-containing alpha-anomeric sugar with a longer fatty acyl chain (C26) and sphingosine base (C18) was identified as a ligand for this TCR. Glycosylceramide-mediated proliferative responses of Valpha14 NKT cells were abrogated by treatment with chloroquine-concanamycin A or by monoclonal antibodies against CD1d/Vbeta8, CD40/CD40L, or B7/CTLA-4/CD28, but not by interference with the function of a transporter-associated protein. Thus, this lymphocyte shares distinct recognition systems with either T or NK cells.

Requirement for Valpha14 NKT cells in IL-12-mediated rejection of tumors

A lymphocyte subpopulation, the Valpha14 natural killer T (NKT) cells, expresses both NK1.1 and a single invariant T cell receptor encoded by the Valpha14 and Jalpha281 gene segments. Mice with a deletion of the Jalpha281 gene segment were found to exclusively lack this subpopulation. The Valpha14 NKT cell-deficient mice could no longer mediate the interleukin-12 (IL-12)-induced rejection of tumors. Although the antitumor effect of IL-12 was thought to be mediated through natural killer cells and T cells, Valpha14 NKT cells were found to be an essential target of IL-12, and they mediated their cytotoxicity by an NK-like effector mechanism after activation with IL-12.

Inhibition of platelet deposition with local delivery of heparin using a double balloon catheter

Heparin is an effective agent in the treatment of unstable angina and myocardial infarction. The clinical utility of heparin is limited by bleeding complications. This study was performed to determine whether static delivery of heparin could effectively inhibit further platelet deposition. Thrombogenic graft segments were incorporated into chronic arteriovenous shunts in pigs. Autologous platelets were labeled with 111Indium. Platelet deposition was quantitated with gamma camera imaging. The grafts were exposed to blood flow for 15 min in order to induce platelet deposition on the thrombogenic surface. Heparin was delivered locally either by direct exposure or with a double balloon catheter. After a 15 minute exposure period, the heparin solution was removed and subsequent platelet deposition was monitored for 90 minutes. Heparin, administered with the double balloon catheter in doses as low as 12.5 U, effectively inhibited further platelet deposition. An intravenous injection of 100 U of heparin, the highest dose use for local delivery, did not perturb bleeding time or the activated partial thromboplastin time. In conclusion, platelet deposition can be inhibited with static local delivery of heparin at doses that are not associated with systemic bleeding.

Response to vestibular stimulation of sympathetic outflow to muscle in humans

The objective of the present study was to determine the effect of vestibular stimulation on the sympathetic outflow to muscle in humans. Fourteen healthy volunteers were studied while in the supine position with electrocardiography, blood pressure monitoring and electro-oculography. The muscle sympathetic nerve activity (MSNA) was recorded directly from the bilateral tibial nerves by using microneurographic double recording technique. Caloric vestibular stimulation was loaded by alternate irrigation with 50 ml of cold (10 degrees C) water and 50 ml of hot (44 degrees C) water into the left and right external meatus. After cold water irrigation, two MSNA response peaks were elicited, respectively, before and after the maximum slow phase velocity (SPV) of nystagmus. The first peak of the MSNA enhancement was caused by non-specific factors because its time course coincided with that in cold pressor test with immersion of the subject's hand in ice/water (4 degrees C). Transient suppression of MSNA after cold water irrigation in the period of maximum SPV of nystagmus was observed by cross correlogram analysis between the SPV of the nystagmus and MSNA. After hot water irrigation, only one MSNA response peak was elicited after the period of strong nystagmus. The second peak of MSNA enhancement evoked by cold irrigation (379.4 +/- 221.8%, with the control value set as 100%, mean +/- SE) was significantly higher than that evoked by hot irrigation (243.0 +/- 14.5%). The degree of MSNA enhancement by either cold (the second peak) or hot stimulation was proportional to the maximum SPV of the nystagmus. There was no significant difference between the MSNA responses ipsilateral to and contralateral to the irrigated side. In conclusion, the caloric vestibular stimulation can influence the bilateral sympathetic outflow to muscle in humans. The degree of MSNA enhancement is proportional to the magnitude of vestibular excitement indicated by maximum slow phase velocity of the nystagmus.

[Phenylethanoid glucosides from flos Buddlejae]

Four phenylethanoid glucosides were isolated from the flower of Buddleja officinalis. On the basis of specteral data, they were identified as salidroside(1), verbascoside(2), isoverbascoside(3) and echinacoside(4). Compounds 1, 3 and 4 were obtained from the plant for the first time. Compound 2 showed antibacterial and anticancer activities.

Allosteric gating of a large conductance Ca-activated K+ channel

Large-conductance Ca-activated potassium channels (BK channels) are uniquely sensitive to both membrane potential and intracellular Ca2+. Recent work has demonstrated that in the gating of these channels there are voltage-sensitive steps that are separate from Ca2+ binding steps. Based on this result and the macroscopic steady state and kinetic properties of the cloned BK channel mslo, we have recently proposed a general kinetic scheme to describe the interaction between voltage and Ca2+ in the gating of the mslo channel (Cui, J., D.H. Cox, and R.W. Aldrich. 1997. J. Gen. Physiol. In press.). This scheme supposes that the channel exists in two main conformations, closed and open. The conformational change between closed and open is voltage dependent. Ca2+ binds to both the closed and open conformations, but on average binds more tightly to the open conformation and thereby promotes channel opening. Here we describe the basic properties of models of this form and test their ability to mimic mslo macroscopic steady state and kinetic behavior. The simplest form of this scheme corresponds to a voltage-dependent version of the Monod-Wyman-Changeux (MWC) model of allosteric proteins. The success of voltage-dependent MWC models in describing many aspects of mslo gating suggests that these channels may share a common molecular mechanism with other allosteric proteins whose behaviors have been modeled using the MWC formalism. We also demonstrate how this scheme can arise as a simplification of a more complex scheme that is based on the premise that the channel is a homotetramer with a single Ca2+ binding site and a single voltage sensor in each subunit. Aspects of the mslo data not well fitted by the simplified scheme will likely be better accounted for by this more general scheme. The kinetic schemes discussed in this paper may be useful in interpreting the effects of BK channel modifications or mutations.

Histopathological and electron microscopical studies on experimental Penicillium marneffei infection in mice

Experimental Penicillium marneffei infection in mice was investigated histopathologically and by electron microscopy. Viable conidia (5 x 10(6) cells) of P. marneffei were inoculated into each mouse of group A (BALB/c mice) and group B (BALB/c-nu/nu-SIc mice) through the tail vein. All the mice were sacrificed at intervals and the livers were examined. In group A, the conidia were phagocytosed by Kupffer cells soon after inoculation, and proliferated by fission in the cytoplasm. Marked proliferation of yeast cells was observed 7 and 14 days after inoculation. With proliferation of the fungus, the number of lysosomes in Kupffer cells increased, and numerous granulomas were formed in the liver. These granulomas consisted mainly of macrophages with yeast cells, together with a few polymorphonuclear leukocytes, lymphocytes and giant cells. From 28 days on yeast cells were gradually cleared from the granulomas, and 56 days after inoculation almost all the granulomas disappeared. In group B, at an early stage of infection, similar pathological changes to those seen in mice of group A were observed. However, as the infection progressed, the number of granulomas continued to increase and yeast cells continued to proliferate although lymphocytes did not infiltrate these granulomas. With proliferation of yeast cells the liver tissue was replaced with both yeast cells engulfed by macrophages and extracellular yeasts, and dissemination occurred.

BRCA1 proteins are transported to the nucleus in the absence of serum and splice variants BRCA1a, BRCA1b are tyrosine phosphoproteins that associate with E2F, cyclins and cyclin dependent kinases

BRCA1, a familial breast and ovarian cancer susceptibility gene encodes nuclear phosphoproteins that function as tumor suppressors in human breast cancer cells. Previously, we have shown that overexpression of a BRCA1 splice variant BRCA1a accelerates apoptosis in human breast cancer cells. In an attempt to determine whether the subcellular localization of BRCA1 is cell cycle regulated, we have studied the subcellular distribution of BRCA1 in asynchronous and growth arrested normal, breast and ovarian cancer cells using different BRCA1 antibodies by immunofluorescence and immunohistochemical staining. Upon serum starvation of NIH3T3, some breast and ovarian cancer cells, most of the BRCA1 protein redistributed to the nucleus revealing a new type of regulation that may modulate the activity of BRCA1 gene. We have also characterized two new variant BRCA1 proteins (BRCA1a/p110 and BRCA1b/ p100) which are phosphoproteins containing phosphotyrosine. Immunofluorescence and Western blotting analysis indicate cytoplasmic and nuclear localization of BRCA1a and BRCA1b proteins. To elucidate the biological function of BRCA1, we created a bacterial fusion protein of glutathione-transferase (GST) and BRCA1 zinc finger domain and detected two cellular proteins with molecular weights of approximately 32 and 65 kD, one of which contains phosphotyrosine designated p32 and p65 BRCA1 interacting proteins (BIP) that specifically interact with BRCA1. Western blot analysis of BIP with cyclins/CDKs and E2F antisera indicated association with cdc2, cdk2, cdk4, cyclin B, cyclin D, cyclin A and E2F-4 but not with cdk3, cdk5, cdk6, E2F-1, E2F-2, E2F-3, E2F-5 and cyclin E. Furthermore, we have also demonstrated a direct interaction of in vitro translated BRCA1a and BRCA1b proteins with recombinant cyclin A, cyclin B1, cyclin D1, cdc2, cdk2 and E2F fusion proteins in vitro. Taken together these results seem to suggest that BRCA1 could be an important negative regulator of cell cycle that functions through interaction with E2F transcriptional factors and phosphorylation by cyclins/cdk complexes with the zinc ring finger functioning as a major protein-protein interaction domain. If the interactions we observe in vitro is also seen in vivo then it may be possible that lack or impaired binding of the disrupted BRCA1 proteins to E2F, cyclins/CDKs in patients with mutations in the zinc finger domain could deprive the cell of an important mechanism for braking cell proliferation leading to the development of breast and ovarian cancers.

Epidemiological and clinical studies on an outbreak of trichinosis in central China

An outbreak of trichinosis occurred in the city of Zhengzhou, central China, between December 1995 and February 1996, affecting 85 of the administrative units into which the city is split. Of 297 subjects from eight of the affected units, 54% were seropositive for Trichinella and 41% had symptoms consistent with acute trichinosis. Of the 490 subjects who had eaten at one particular dumpling restaurant 1-5 weeks before the outbreak and who were traced, 291 (59%) were seropositive and 212 (43%) had been or were ill. MOst of the infections were in manual workers, cadres and merchants aged 20-49 years. Most of those who had been infected failed to develop gastro-intestinal symptoms or a cutaneous rash. Eyelid oedema was only seen in the early stages of the infection, the main clinical manifestations being fever of long duration of tiredness. Surprisingly, six cases had no marked symptoms after repeated infection. Eosinophilia (eosinophils > 7% of leucocytes) was noted in 71 (55%) of the 130 cases in which blood cells were counted. When 212 sera were tested for antibodies to Trichinella, seropositivities were found to increase from 89.1% (IFAT) of 87.7% (microprecipitation test) at presentation to 100% (both tests) 1 week after treatment with albendazole. All those treated were cured. The outbreak was one of the most extensive, single-source outbreaks ever recorded in China, probably with > 600 infections and > 300 clinical cases. The entire episode was attributed to the ingestion of undercooked pork dumplings at one restaurant.

[Using lyophilization to the preparation of drug paper disks for antimicrobial susceptibility test]

It was found that the paper disks used in the antimicrobial susceptibility test could be prepared by natural drying at 37 degrees C, but the drug distribution between these disks is not so enen as determined by antimicrobial inhibitory test, thus it was difficult to fit the needs of the national standards. Alternatively, we applied the lyophilization technique to the disks preparation and 12 batches, of different antibiotic disks were made out and found that the difference between disks is reduced, and all are meet to the national requirement. It is supposed that the capillary action may play a role in the variation of drug distribution in the natural drying process, and the lyophilization process avoided the capillary action, hence the more even distributed antibiotic disks are produced. The preparation of lyophilized disks is a simple and practical method that could be used in the antimicrobial susceptibility tests in hospital.

Intrinsic voltage dependence and Ca2+ regulation of mslo large conductance Ca-activated K+ channels

The kinetic and steady-state properties of macroscopic mslo Ca-activated K+ currents were studied in excised patches from Xenopus oocytes. In response to voltage steps, the timecourse of both activation and deactivation, but for a brief delay in activation, could be approximated by a single exponential function over a wide range of voltages and internal Ca2+ concentrations ([Ca]i). Activation rates increased with voltage and with [Ca]i, and approached saturation at high [Ca]i. Deactivation rates generally decreased with [Ca]i and voltage, and approached saturation at high [Ca]i. Plots of the macroscopic conductance as a function of voltage (G-V) and the time constant of activation and deactivation shifted leftward along the voltage axis with increasing [Ca]i. G-V relations could be approximated by a Boltzmann function with an equivalent gating charge which ranged between 1.1 and 1.8 e as [Ca]i varied between 0.84 and 1,000 microM. Hill analysis indicates that at least three Ca2+ binding sites can contribute to channel activation. Three lines of evidence indicate that there is at least one voltage-dependent unimolecular conformational change associated with mslo gating that is separate from Ca2+ binding. (a) The position of the mslo G-V relation does not vary logarithmically with [Ca]i. (b) The macroscopic rate constant of activation approaches saturation at high [Ca]i but remains voltage dependent. (c) With strong depolarizations mslo currents can be nearly maximally activated without binding Ca2+. These results can be understood in terms of a channel which must undergo a central voltage-dependent rate limiting conformational change in order to move from closed to open, with rapid Ca2+ binding to both open and closed states modulating this central step.

Separation of gating properties from permeation and block in mslo large conductance Ca-activated K+ channels

In this and the following paper we have examined the kinetic and steady-state properties of macroscopic mslo Ca-activated K+ currents in order to interpret these currents in terms of the gating behavior of the mslo channel. To do so, however, it was necessary to first find conditions by which we could separate the effects that changes in Ca2+ concentration or membrane voltage have on channel permeation from the effects these stimuli have on channel gating. In this study we investigate three phenomena which are unrelated to gating but are manifest in macroscopic current records: a saturation of single channel current at high voltage, a rapid voltage-dependent Ca2+ block, and a slow voltage-dependent Ba2+ block. Where possible methods are described by which these phenomena can be separated from the effects that changes in Ca2+ concentration and membrane voltage have on channel gating. Where this is not possible, some assessment of the impact these effects have on gating parameters determined from macroscopic current measurements is provided. We have also found that without considering the effects of Ca2+ and voltage on channel permeation and block, macroscopic current measurements suggest that mslo channels do not reach the same maximum open probability at all Ca2+ concentrations. Taking into account permeation and blocking effects, however, we find that this is not the case. The maximum open probability of the mslo channel is the same or very similar over a Ca2+ concentration range spanning three orders of magnitude indicating that over this range the internal Ca2+ concentration does not limit the ability of the channel to be activated by voltage.

Phenotypes and invariant alpha beta TCR expression of peripheral V alpha 14+ NK T cells

A novel subset of peripheral T cells, peripheral NK T cells, is found to be a major population comprising 5% of splenic T and 40% of bone marrow T cells. The majority of peripheral NK T cells are characterized by the expression of an invariant TCR-alpha encoded by V alpha 14/J alpha 281 with a one nucleotide N region. Moreover, a specific reduction of V alpha 14+ NK T cells has been demonstrated to be tightly associated with various autoimmune diseases, indicating their decisive role in autoimmune disease development. In this study, we investigated the phenotypes of peripheral V alpha 14+ NK T cells and their TCR-beta repertoire. Peripheral V alpha 14+ NK T cells, comprise two populations, i.e., small and large sized cells, at an equal frequency, belonged to the CD4- CD8- fraction, and are heat stable antigen(bright), macrophage-1bright, B220bright, CD45RBdim, and Mel-14dim, but CD5-, distinct from thymic NK T cells. TCR-beta analysis clearly showed that peripheral V alpha 14+ NK T cells utilized two to three dominant invariant TCR-beta, such as V beta 8.2 D beta J beta 2.5/V beta 7 D beta J beta 2.1 in the spleen and liver, V beta 8.2 D beta J beta 2.5/V beta 8.3 D beta J beta 2.2/V beta 7 D beta J beta 2.6 in the bone marrow, and V beta 7 D beta J beta 2.1/V beta 3 D beta J beta 1.2 in intestinal intraepithelial lymphocytes. Judging from the unusual surface phenotypes, such as heat stable antigen, macrophage-1, B220, CD45RBdim, and Mel-14dim, which are known to be T cell activation markers, peripheral V alpha 14+ NK T cells may always be activated under physiologic conditions, resulting in the oligoclonal expansion of V alpha 14+ NK T cells with different invariant TCR-beta in different peripheral organs. The unique features of V alpha 14+ NK T cells are discussed.

Phenotypes and invariant alpha beta TCR expression of peripheral V alpha 14+ NK T cells

A novel subset of peripheral T cells, peripheral NK T cells, is found to be a major population comprising 5% of splenic T and 40% of bone marrow T cells. The majority of peripheral NK T cells are characterized by the expression of an invariant TCR-alpha encoded by V alpha 14/J alpha 281 with a one nucleotide N region. Moreover, a specific reduction of V alpha 14+ NK T cells has been demonstrated to be tightly associated with various autoimmune diseases, indicating their decisive role in autoimmune disease development. In this study, we investigated the phenotypes of peripheral V alpha 14+ NK T cells and their TCR-beta repertoire. Peripheral V alpha 14+ NK T cells, comprise two populations, i.e., small and large sized cells, at an equal frequency, belonged to the CD4- CD8- fraction, and are heat stable antigen(bright), macrophage-1bright, B220bright, CD45RBdim, and Mel-14dim, but CD5-, distinct from thymic NK T cells. TCR-beta analysis clearly showed that peripheral V alpha 14+ NK T cells utilized two to three dominant invariant TCR-beta, such as V beta 8.2 D beta J beta 2.5/V beta 7 D beta J beta 2.1 in the spleen and liver, V beta 8.2 D beta J beta 2.5/V beta 8.3 D beta J beta 2.2/V beta 7 D beta J beta 2.6 in the bone marrow, and V beta 7 D beta J beta 2.1/V beta 3 D beta J beta 1.2 in intestinal intraepithelial lymphocytes. Judging from the unusual surface phenotypes, such as heat stable antigen, macrophage-1, B220, CD45RBdim, and Mel-14dim, which are known to be T cell activation markers, peripheral V alpha 14+ NK T cells may always be activated under physiologic conditions, resulting in the oligoclonal expansion of V alpha 14+ NK T cells with different invariant TCR-beta in different peripheral organs. The unique features of V alpha 14+ NK T cells are discussed.

[Volume loading experiment in dogs with large area infarction of right and left ventricles]

In order to study volume loading effect on large area myocardial infarction (MI) in right and left ventricles, large area MI in both ventricles and cardiogenic shock in 12 dogs were induced by occluding coronary arteries. Left ventricular systolic pressure (LVSP) and +/- dp/dt max. dropped markedly by 54%, 51% and 47% respectively, whereas right ventricular systolic pressure (RVSP) and +/- dp/dt max. fell by 9%, 25% and 27% respectively. The condition was obviously worse by rapid volume loading (dextran, 30 ml/kg, i.v. in 20 min.) in group I (n = 6), leading to increased retrograde beat of right ventricle, further decrease of +/- dp/dt max. in both ventricles, significant increase of right atrial pressure (RAP) and left ventricular and diastolic pressure (LEVDP) (2.9 +/- 0.2 kPa, P < 0.01 and 5.0 +/- 0.3 kPa, P < 0.001, respectively), and even ventricular fibrillation. Shock was reversed by combined treatment of dopamine (10 micrograms/kg.min) and glyceryl trinitrate (1 microgram/kg.min) in group II (n = 6) in 30 min, showing evident increase of arterial pressure, cardiac output, LVSP and +/- dp/dt max. without rise in RAP and LVEDP.

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.