Serum stimulation of quiescent human fibroblasts induces the synthesis of tissue factor mRNA followed by the appearance of tissue factor antigen and procoagulant activity

Expression of the gene for tissue factor, the cell-surface initiator of blood coagulation, was examined by stimulating growth-arrested human fibroblasts with serum and measuring changes in the cellular content of tissue factor mRNA, antigen, and activity. Maximum tissue factor mRNA levels were reached within 1 h following serum induction and slowly declined to basal levels from 24 to 48 h after stimulation. The appearance of the tissue factor mRNA was followed by an increase in tissue factor antigen and activity. The parallel rise in antigenically positive protein and procoagulant activity was first observed about 2 h after serum stimulation with a peak at 12 h followed by a slow decline during the next 36 h. The serum-induced synthesis of the tissue factor mRNA was independent of de novo protein synthesis as demonstrated by the increased tissue factor mRNA levels generated in the presence of cycloheximide. The results of this study suggest that the synthesis of tissue factor in human fibroblasts is regulated principally at the level of transcription. In one strain of fibroblasts the activity/antigen ratio, during the period of maximum synthesis, was indistinguishable from that of tissue factor which had been immunoaffinity purified from human brain and reconstituted into phospholipid vesicles. However, during serum starvation the activity/antigen ratio in these cells was significantly reduced. Western blot analysis revealed that in serum-starved cells there was an accumulation of truncated forms of the tissue factor antigen while in the serum-stimulated cells only the full-length antigen was observed.

Antagonism of serum of mice infected with chloroquine-resistant 'NS' line to the antimalarial action of chloroquine

Chloroquine (CQ) solution was separately mixed with the serum of mice infected with chloroquine-resistant 'NS' line (SMNS), the serum of mice infected with chloroquine-sensitive Plasmodium berghei ANKA strain (SMCS), and the serum of normal mice (SM). These mixtures were then used in treating mice inoculated with P. berghei ANKA strain. The results obtained on d 5 after drug-serum administration showed that the erythrocyte infection rates in the SMNS + CQ, SMCS + CQ, and SM + CQ groups were 32, 16, and 14% respectively. There were significant differences with respect to parasitemia between the SMNS + CQ group and the SMCS + CQ or SM + CQ group (P less than 0.05), suggesting that SMNS may be antagonistic to the antimalarial action of chloroquine. Further study showed that when the 'NS' line lost resistance to chloroquine, the antagonism of SMNS to chloroquine disappeared. The antagonism rates of SMNS to chloroquine, piperaquine, hydroxypiperaquine and pyronaridine were 75, 56, -5, and -17% respectively, a trend similar to that of the results from cross-resistance tests on chloroquine-resistant P. berghei ANKA strain. The results indicate that drug-resistant malaria parasites may produce and release a certain 'specific anti-drug substance'.

[The Balint syndrome]

This paper reports a case of complete form of Bálint syndrome. A 56-year-old male suffered form psychic paralysis of gaze, impaired visual attention and optic ataxia of sudden onset in the basis of sequlae of cerebral vascular disease. CT scans of the present case demonstrated low densities in the left frontal, parietal lobe and right basal ganglia, right parito-occipital lobe. As for possible anatomical substrate of the Balint syndrome. according to Damasio's atlas, the authors inferred that despit the multiplicity of lesions in the present case, prefrontal area, lobulus paritalis inferior gyrus angularis and the associated fibers between the prefrontal area and 18, 19 area of occipital lobe were considered to be most responsible for the production of the Balint syndrome.

[Cross correlation function of BAEP for objective assessment of hearing threshold]

Brainstem auditory evoked potentials (BAEP) recorded were equally divided into two subensembles and a cross correlation function R (lambda) was calculated for them. The average amplitude of R (lambda) around lambda = 0 was chosen as the criterion for hearing threshold measurement. A linear regression equation which represented the relationship between the criterion and stimulus intensity above threshold was obtained on 21 normal and abnormal ears and thus a equation for assessment of hearing threshold was derived. When the equation was applied to ears to be evaluated, the criteria obtained at three different stimulus intensities above threshold were put into the equation and the mean value was calculated for assessment of hearing threshold. The results from 8 ears with different degrees of hearing loss demonstrated that the differences between estimated thresholds and corresponding subjective thresholds are 4.6 dB on the average.

Cardiac gap junctions and gap junction-associated vesicles: ultrastructural comparison of in situ negative staining with conventional positive staining

By comparing in situ negative staining of mammalian heart muscle using La(NO3)3 with conventional positive staining by uranium and lead salts, we showed that 1) the membrane area of rat cardiac gap junctions (GJs) at the intercalated disks is threefold to fourfold greater than previously thought; 2) connexon arrays of cardiac GJ are subdivided into microdomains by connexon-free aisles; 3) profiles of GJ-associated vesicles (GJAVs) of plasmalemmal origin (which are present extracellularly and sharply localized at three extracellular sites) are paired to form GJs with each other and with myocyte plasmalemma; 4) some GJAVs contain arrays of assembled connexons; and 5) myocytes contain intracytoplasmic complexes lying within cylindrical or cigar-shaped membranes and consisting of GJs and multiple vesicles apparently dissociating from these GJs.

Mechanical factors do not influence blood flow distribution in atelectasis

The contribution of mechanical factors to the vascular resistance of the atelectatic lung has been studied in vivo in the anesthetized open-chest dog. When the left lung was ventilated with an hypoxic gas mixture (while the right lung was ventilated with 100% O2), left lung blood flow decreased from 0.99 +/- 0.11 1.min-1 to 0.40 +/- 0.08 1.min-1 due to hypoxic pulmonary vasoconstriction (hypoxic stimulus PSO2 = 36.1 +/- 0.8 mmHg). When the left lung was made atelectatic, blood flow decreased to 0.65 +/- 0.11 1.min-1, consistent with a weaker hypoxic stimulus (PSO2 = 54.0 +/- 3.2 mmHg). With the addition of sodium nitroprusside infused intravenously, left lung blood flow increased to 1.05 +/- 0.14 1.min-1 during atelectasis, and to 0.61 +/- 0.09 1.min-1 during hypoxic ventilation, while flow remained at 0.94 +/- 0.18 1.min-1 during hyperoxic ventilation. When the results were plotted on pressure-flow diagrams, the hyperoxic, hypoxic, and atelectatic lung points fell on the same pressure-flow line in the presence of nitroprusside. It is concluded that hypoxic pulmonary vasoconstriction is the major (but not necessarily only) determinant of increased vascular resistance in the atelectatic lung, and that passive mechanical factors do not measurably affect blood flow distribution during open-chest atelectasis.

Purification of the Escherichia coli secB gene product and demonstration of its activity in an in vitro protein translocation system

Mutations in the Escherichia coli secB gene lead to protein export defects in vivo (Kumamoto, C.A., and Beckwith, J. (1985) J. Bacteriol. 163, 267-274). To demonstrate directly the participation of the secB gene product (SecB) in protein export, SecB was purified, and its effects on in vitro protein translocation were analyzed. SecB was purified from soluble extracts of a strain that overproduced it, by ammonium sulfate precipitation, DEAE-cellulose chromatography, and differential precipitation at acid pH. The chromatographic behavior on gel filtration columns indicated apparent molecular masses of approximately 90 kDa for both purified SecB and SecB in cytosolic extracts of wild type cells. When added to a translocation mixture, purified SecB stimulated pro-OmpA translocation into membrane vesicles. SecB also suppressed the thermoinduced defect in translocating activity of membranes derived from a secY24 mutant. The results of these in vitro studies and of previous in vivo studies demonstrate that SecB plays a direct role in normal protein export in E. coli.

Molecular and cellular responses of islets during perturbations of glucose homeostasis determined by in situ hybridization histochemistry

We have evaluated in situ hybridization histochemistry as a means of estimating simultaneously the level of prohormone mRNA and the dimensions of rat pancreatic islets. Localization of the 27-mer 32P-labeled oligonucleotide probes for rat proinsulin I, glucagon, and prosomatostatin I corresponded with localization of antibodies to the three hormones. In normal rats subjected to chronic hyperglycemic clamping, the density of the proinsulin mRNA signal increased 54%, islet size and number increased approximately 100%, while proglucagon mRNA signal was reduced 81%. Resection of 50% of the pancreas increased proinsulin mRNA 36% and proglucagon mRNA 500%; islet area doubled and islet number increased 50%. In 150-day-old diabetic ob/ob mice, there was an 18-fold expansion in islet area, a 4-fold increase in islet number, but no increase in insulin gene expression. In insulin-dependent streptozotocin-treated diabetic rats, islet area and number were profoundly reduced; insulin deprivation failed to raise proinsulin mRNA in surviving beta cells above control levels. Proglucagon mRNA was high despite the hyperglycemia but was reduced by insulin within 1 hr, suggesting that insulin regulates glucagon gene expression or is required for its regulation by glucose. In situ hybridization of rat islets provides a valid semiquantitative index of insulin and glucagon biosynthesis and of islet dimensions and reveals that normal but not diabetic islets meet increased insulin demand by increasing both number and biosynthetic activity of beta cells.

[Research on the dose-response relationship of hand transmitted vibration and its hygienic standard]

According to ISO 5349-1986, the akw(4) was 9.04-41.47m/s2 which was measured and calculated in 5 types of instruments: chain saw, cleaner, rock driller, riveter & emery wheel. There were 170 cases with white finger through epidemiologic investigation on 5 types of workers in 1,675 persons. Based on the work mentioned above, a formula, which represented worker cumulative exposure to vibration was deduced: D = [(a2kw(4).T)1/2.Y.d]2 Furthermore, the dose-response relationship of hand transmitted vibration and prevalence of white finger was computed, the regression equation was: P = 1.0904X - 6.214 2 Under precondition of exposure to vibration for 20 years with 90% of workers having no white fingers, the limit of hygienic standard of hand transmitted vibration in china should be set at 4 hours and as akw(4) less than or equal to 5 m/s2 based on the regression equation.

[The effect of biphenyl dimethyl dicarboxylate (DDB) on the fluidity of human erythrocyte membrane]

This paper deals with the effects of DDB on human RBC membrane fluidity as reflected by changes in the phase transition temperature and microviscosity monitored by ANS, NPN and DPH. The results showed that DDB decreased the fluidity of the shallow layer (ANS as probe), but increased the fluidity of the middle layer (NPN as probe) and deeper layer (DPH as probe). In addition, the drug was found to inhibit the hemolysis induced by MDA.

SecA protein is required for secretory protein translocation into E. coli membrane vesicles

The soluble and membrane components of an E. coli in vitro protein translocation system prepared from a secA amber mutant, secA13[Am], contain reduced levels of SecA and are markedly defective in both the cotranslational and posttranslational translocation of OmpA and alkaline phosphatase into membrane vesicles. Moreover, the removal of SecA from soluble components prepared from a wild-type strain by passage through an anti-SecA antibody column similarly abolishes protein translocation. Translocation activity is completely restored by addition of submicrogram amounts of purified SecA protein, implying that the observed defects are solely related to loss of SecA function. Interestingly, the translocation defect can be overcome by reconstitution of SecA into SecA-depleted membranes, suggesting that SecA is an essential, membrane-associated translocation factor.

Recombinant interferon-beta 2 (interleukin-6) induces myeloid differentiation

Human IFN-beta 2 cytokine produced in E. coli was purified to homogeneity by immunoaffinity and ion-exchange chromatography. The cytokine inhibits the growth of myeloleukemic M1 cells and induces their morphological and functional differentiation into macrophages. Differentiation was also observed in the histiocytic lymphoma U937 cells. The effect on U937 was synergized by IFN-gamma and under these conditions IFN-beta 2 produced the induction of (2'-5') oligo(A) synthetase typical to IFN action and to differentiation.

Growth inhibition of human breast carcinoma and leukemia/lymphoma cell lines by recombinant interferon-beta 2

Recombinant human interferon-beta 2 was produced in Escherichia coli by direct expression of cDNA encoding the mature protein sequence. At concentrations that stimulate DNA synthesis and growth in B-cell hybridomas and plasmacytomas, the cytokine was found to exert a strong inhibition on the growth of a number of carcinoma and leukemia/lymphoma cell lines. This antigrowth effect was observed in clonogenic assays and by measurements of cell number and thymidine incorporation in growing cultures. The effect was blocked by antibodies to a synthetic peptide from the N terminus of the molecule. Normal diploid fibroblasts were inhibited at concentrations higher than those needed for breast carcinoma cells.

Dimerization of the tat protein from human immunodeficiency virus: a cysteine-rich peptide mimics the normal metal-linked dimer interface

We have synthesized an 18-amino acid peptide that contains the cysteine-rich region of the tat protein from human immunodeficiency virus. Previous experiments in vitro with the intact tat protein have shown that these cysteines serve as metal ligands, causing tat to form metal-linked dimers. Ultraviolet absorption spectra show that the synthetic peptide (tat21-38) binds two Cd2+ or two Zn2+ ions per peptide monomer, and some changes in the circular dichroism spectra are seen as the metals bind. The peptide-metal complexes are completely resistant to proteolytic digestion, and mass spectrometry demonstrates that this peptide forms metal-linked dimers. The peptide can also combine with the intact tat protein to form metal-linked heterodimers. If these heterodimers are unable to trans-activate viral transcription, tat21-38 could be a lead compound for designing drugs to treat acquired immunodeficiency syndrome.

The effect of pleural pressure on the hypoxic pulmonary vasoconstrictor response in closed chest dogs

The effect of intrapleural pressure on the hypoxic pulmonary vasoconstrictor (HPV) responses to atelectasis and hypoxia were measured in two groups of anesthetized closed chest dogs. The right lung was continuously ventilated with 100% O2. The left lung was initially ventilated with 100% O2 (hyperoxia) but subsequently underwent either reabsorption atelectasis (atelectasis; group I) or ventilation with a hypoxic gas mixture (hypoxia; group II). The mean intrapleural pressure in the left hemithorax was 5.4 cm H2O during hyperoxia, but with left lung atelectasis decreased significantly to -3.8 cm H2O by 15 minutes and to -4.2 cm H2O by 90 minutes. Venous admixture (% VA) increased significantly from 10.3% during hyperoxia to 33.2% at 15 minutes of left lung atelectasis and to 34.6% at 90 minutes. However, after sternotomy with the left lung still atelectatic, the %VA decreased significantly to 25.4% For the hypoxia group, %VA increased significantly from 9.2% during hyperoxia to 29.9% at 15 minutes of left lung hypoxia and 25.1% at 90 minutes. HPV diverted blood flow away from both atelectatic lung and hypoxic lung. However, due to the negative intrapleural pressure generated during left lung resorption atelectasis when the chest was closed, HPV was less effective during atelectasis than during hypoxia.