Role for c-myc in activation-induced apoptotic cell death in T cell hybridomas

Immature T cells and some T cell hybridomas undergo apoptotic cell death when activated through the T cell receptor complex, a phenomenon that is probably related to antigen induced negative selection of developing T cells. This activation-induced apoptosis depends on active protein and RNA synthesis in the dying cells, although none of the genes required for this process have previously been identified. Antisense oligonucleotides corresponding to c-myc block the constitutive expression of c-Myc protein in T cell hybridomas and interfere with all aspects of activation-induced apoptosis without affecting lymphokine production in these cells. These data indicate that c-myc expression is a necessary component of activation-induced apoptosis.

Comparison of the properties of the CsA analogs monoacetyl CyC (o-acetyl-threonine2 cyclosporin) and methyl-alanyl CsA (N-methyl-L-alanyl6 cyclosporin); monoacetyl cyclosporin is immunosuppressive without binding to cyclophilin

Cyclosporin (CsA) is an immunosuppressant which binds to cyclophilin (Cyp). The relationship between Cyp binding and immunosuppression has been questioned since one of the analogs of CsA, N-methyl-L-alanyl6 cyclosporin (methyl-alanyl CsA) binds to Cyp but is not immunosuppressive. We compared the immunosuppressive properties of CsA, methyl-alanyl CsA and o-acetyl-threonine2 cyclosporin (monoacetyl CyC), since monoacetyl CyC does not bind to Cyp when tested in cell-free assays and its immunosuppressive properties had not been tested. Cyp is a peptidyl-prolyl isomerase which is abundant in all human tissues, yet the activities of CsA are mostly confined to inhibition of T cell and thymocyte activation, and to neuro- and nephro-toxicity and are independent of inhibition of the isomerase. Activation of thymocytes and of T cells is regulated by the binding of a nuclear factor(s) (NFs) to the NF-AT region (-285 to -255) of the IL-2 promoter. We studied inhibition of binding to the NF-AT region of NFs derived from primary cultures of thymocytes treated with CsA or its analogs. In addition, we compared the effect of CsA and its analogs on the expression of the IL-2 gene in a stably transfected Jurkat-cell line (Fgl 5) which contains three copies of NF-AT and the reporter enzyme beta-galactosidase; and on inhibition of proliferation induced by concanavalin A (Con A) or IL-2. We found that monoacetyl CyC which does not bind to Cyp is immunosuppressive by our criteria when tested in cultured cells due to either a different mechanism of action or to metabolic activation.

[Isolation and identification of a strain of Pseudomonas SP. producing insoluble glucan hydrolase]

A strain, CIB871, isolated from the natural world can hydrolyze insoluble glucan(IG) produced by S. mutans. This organism has been identified to be a strain of Pseudomonas SP. It grows well at 30 degrees C. The optimum medium for producing insoluble glucan hydrolase (IGase) is composed of 0.3% peptone, 0.03% IG and M1 salt solution (NH4)2 SO4 1mg/ml, MgSO4 50 micrograms/ml, FeCl2 50 micrograms/ml, K2HPO4 0.5mg/ml). The IGase production reached maximum when cultured for 65-70 hours.

[The construction of rich genomic library of bovine Y chromosome]

According to the fundamentals of DNA renatured kinetics, we made a study in which genomic DNA from male cattle was completely digested with Sau 3A, while female DNA was sheared to an average size of 500 bp fragments. The Y derived DNA sequence rich library of bovine has been contracted with pUC19 plasmid as vector and JM109 as host bacteria by reassociation of male and female DNA. Male and female DNA probes, were used. The result of colony hybridization showed that out of 1000 recombinants analysed, 6 were found to be stronger signal with male probe. Analysis of Pvu' I digested DNA fragment revealed that most of the inserts were in the 90-300 bp.

The transport of proteins into the nucleus requires the 70-kilodalton heat shock protein or its cytosolic cognate

The 70-kDa heat shock protein hsp70 and its constitutively expressed cognate, hsc70, are abundant proteins implicated in a number of cellular processes. When a permeabilized cell system for examining the transport of proteins into the nucleus is depleted of hsc70 and hsp70, either by affinity chromatography on ATP-agarose or with antibodies against these proteins, nuclear transport activity is lost. Full activity is restored by the addition of HeLa proteins that bind to ATP-agarose. hsc70 and hsp70 are the active factors, since activity is also fully restored by the addition of either recombinant hsc70 or hsp70 which has been bacterially expressed and highly purified. The restoration of activity is saturable. The transport system requires other cytosolic factors as well, including at least one protein that is sensitive to inactivation by N-ethylmaleimide, but neither hsc70 nor hsp70 is the sensitive protein.

Early luteal progesterone supplementation during in vitro fertilization cycles. A randomized trial

The effects of early luteal phase progesterone (P) supplementation were studied in women with endogenous serum P levels less than or equal to 12 ng/mL prior to embryo transfer. From a total of 129 cycles that received the same ovarian hyperstimulation protocol, 72 cycles were characterized by levels less than 12 ng/mL on the day prior to embryo transfer. Of those women, 42 (group B) were started on P supplementation one day prior to embryo transfer, and 30 (group C) were started according to the standard protocol after embryo transfer. The clinical course and outcomes in both groups were compared with 57 cycles that had P levels greater than or equal to 12 ng/mL (group A). The early P supplementation in group B resulted in a transient increase in P levels on the morning of embryo transfer as compared with group C. It did not, however, approach the levels seen in group A, which had higher P levels from the early luteal phase through embryo transfer and more favorable oocyte recovery, fertilization and cleavage rates. We were unable to improve the clinical outcome in group B as compared with group C by providing earlier P supplementation.

Microcarrier culture of fish cells and viruses in cell culture bioreactor

This article deals with the culture of grass carp (Ctenopharyngodon idellus) lip and embryo cells on Cytodex 3 and GT-2 microcarriers in a 1.5-L cell culture bioreactor to propagate grass carp hemorrhage virus. The cells and viruses were successfully cultivated at 26 degrees C, pH 7.0, and dissolved oxygen 40% of air saturation. The cell density achieved was as high as 7.4 x 10(6) cells/mL, and the virus titre reached 6.75 log LD50/0.5 mL from an initial 3.00 log LD50/0.5 mL. The results present broad prospects for fish virus vaccine production.

WHO pathfinder caries survey in Beijing extended with data for prevalence of mutans streptococci

A pathfinder caries survey was carried out in Beijing, People's Republic of China, using WHO standard methodologies, in order to estimate the trend by comparing the results with the 1981 caries survey, performed in the same area. Simultaneously, the levels of mutans streptococci in the group were estimated in order to define the proportion of children with high and low mutans levels. Twelve-year-old children were randomly selected from schools in five districts within the city limits. Examinations for caries were performed according to 'WHO Oral Health Surveys' by two calibrated examiners. A total of 178 children were examined for caries and 156 of them were randomly selected for saliva sampling of mutans streptococci, using the 'Strip mutans' method. The number of colonies adhering to the strips were compared with a chart, supplied by the manufacturer, and given a score between 0 and 3, indicating low to very high saliva mutans counts, respectively. The results showed a mean DMFT of 1.87 (1.61-0.06-0.20, for decayed, missing and filled teeth respectively); 66.3 per cent of the children were affected. Fourteen per cent had mutans class 0, 28 per cent class 1, 35 per cent class 2 and 23 per cent class 3. The mean DFT, for each mutans class was 0.82, 1.48, 2.09 and 2.69, respectively. The differences were statistically significant (P = 0.0015). In the lowest mutans class, 50 per cent had caries and the mean number of teeth requiring conservative care was 0.68. For the high mutans group, the corresponding values were 72 per cent and 2.11 teeth.(ABSTRACT TRUNCATED AT 250 WORDS)

Fibrinolytic activity after vessel wall injury

The goal of this study was to assess fibrinolytic activity after vessel wall injury and to correlate changes in fibrinolytic activity with angiographic and histologic findings. Accordingly, in 18 atherosclerotic rabbits, vessel wall injury was produced by means of iliac artery balloon angioplasty (the injury group), whereas 8 atherosclerotic rabbits served as a control group. In all rabbits from the injury group, deep vessel wall injury was documented by either angiography or histologic study. Plasminogen activator inhibitor-1 activity in plasma increased significantly, from 21.79 +/- 1.29 arbitrary units/ml (AU/ml) at baseline study to 32.05 +/- 1.47 AU/ml at 6 h after vessel wall injury (p less than 0.01), whereas activity remained unchanged throughout the 24-h period in the control group. Plasma levels of tissue plasminogen activator activity were similar in both groups. Intravascular thrombus was found in five of six additional rabbits 6 h after vessel wall injury, that is, at the time of impaired fibrinolytic activity, whereas no thrombus was found in the control group (p less than 0.05). It is concluded that deep vessel wall injury is associated with reduced fibrinolytic activity. In addition to other procoagulant factors, elevated plasminogen activator inhibitor-1 activity may lead to intravascular thrombosis and impaired resolution of thrombus.

YY1 is an initiator sequence-binding protein that directs and activates transcription in vitro

Regulation of eukaryotic messenger RNA transcription is governed by DNA sequence elements that serve as binding sites for sequence-specific transcription factors. These include upstream and downstream promoter-proximal elements, enhancers, repressors, and silencers, which modulate the rate of specific initiation by RNA polymerase II. In addition, the promoter-proximal region between -45 and +30 (relative to the start of initiation) contains two highly conserved motifs, the TATA sequence at around -30 and CA at +1. Although the TATA element-binding factor TFIID has been purified and cloned from several organisms and has provided invaluable insight into the process of transcription initiation and its regulation, little is known about factors that interact at the +1 region. We have recently shown that the adeno-associated virus type 2 P5 promoter +1 region (P5 + 1 element) binds transcription factor YY1. We report here that this sequence is necessary and sufficient for accurate basal transcription. Further, partially purified YY1 can restore basal level transcription from a P5 + 1 element in a HeLa extract depleted for YY1 or a Drosophila embryo extract devoid of YY1 activity, whereas a YY1-specific antibody can block the reactivation. Finally, using electrophoretic mobility shift assay, we have identified YY1-related factors that bind to two other transcription initiators in cellular genes.

Transcriptional repression by YY1, a human GLI-Krüppel-related protein, and relief of repression by adenovirus E1A protein

A sequence within the transcription control region of the adeno-associated virus P5 promoter has been shown to mediate transcriptional activation by the adenovirus E1A protein. We report here that this same element mediates transcriptional repression in the absence of E1A. Two cellular proteins have been found to bind to overlapping regions within this sequence element. One of these proteins, YY1, is responsible for the repression. E1A relieves repression exerted by YY1 and further activates transcription through its binding site. A YY1-specific cDNA has been isolated. Its sequence reveals YY1 to be a zinc finger protein that belongs to the GLI-Krüppel gene family. The product of the cDNA binds to YY1 sites. When fused to the GAL4 DNA-binding domain, it is capable of repressing transcription directed by a promoter that contains GAL4-binding sites, and E1A proteins can relieve the repression and activate transcription through the fusion protein.

[Relation between psychoactive drugs and body weight among inpatients]

A self-control study was conducted among 92 inpatients for the purpose of the establishment of the relationship between psychoactive and body weight, with the latter measured once a week, stepwise regression (alpha = 0.3) revealed: increase or decrease of body weight was associated not only with the kinds of medicines administered, but also with the types of the diseases, living standard, and therapeutic effects. The mechanism of body weight increase was explored and some suggestions were also given with regard to the prevention of the increase of body weight.

[Consecutive observation of the plasma MDA, XO and UA levels and erythrocyte SOD in 10 cases of cardiopulmonary bypass]

The plasma malonaldehyde (MDA), xanthine oxidase (XO) and uric acid (UA) levels and erythrocyte superoxide dismutase (SOD) were measured in 10 cases during cardiopulmonary bypass (CPB) operation. These examinations were taken at pre-aortic clamping, 15 min after aortic clamping, 30, 60, 120 and 180 min after reperfusion respectively. The results showed that MDA, XO and UA rise but SOD decreases after reperfusion. We believe that a lot of oxygen free radicals (OFR) release during peri-operative period and the XO may be an important pathway of OFR release.

Nonlinear system identification by m-pulse sequences: application to brainstem auditory evoked responses

The purpose of this paper is to introduce a method for characterizing the nonlinear behavior of the auditory system. The method uses an m-pulse sequence as the stimulus and employs a general nonlinear framework for the auditory system. Like Sutter's binary m-sequence approach, the m-pulse sequence approach is computationally efficient since calculation of the first-order input-output cross-correlation function is all that is necessary for obtaining the nonlinear characteristics of the system. The nonlinear system characteristics are reflected in pulse kernels in contrast to binary kernels associated with the binary m-sequence approach. By assuming the system under study is a third-order nonlinear system, binary and pulse kernels are shown to be related to Volterra kernels. The results suggest that the m-pulse sequence can be used to study the system nonlinear effects of varying the stimulus repetition rate more effectively than conventional methods. Preliminary physiological data obtained by applying m-pulse sequences to the brainstem auditory evoked response (BAER) clearly illustrates the feasibility of obtaining replicable evoked responses using this method.

Negative regulation of the BZLF1 promoter of Epstein-Barr virus

The Epstein-Barr virus BZLF1 gene product (ZEBRA) is a transcriptional activator whose expression in latently infected B cells is sufficient to induce the viral lytic cycle. Since there is no transcription of BZLF1 during latency, we carried out experiments to determine whether cis-acting negative elements in the BZLF1 promoter contribute to the lack of expression during this phase of the virus cycle. A series of deletion plasmids encompassing positions -551 to +14 of the BZLF1 promoter region were constructed and tested for the ability to drive chloramphenicol acetyltransferase (CAT) gene expression in the absence of inducing agents such as 12-O-tetradecanoylphorbol-13-acetate (TPA) and anti-immunoglobulin. Expression from the intact 551-bp region was very weak in most of the cell lines tested, but deletion of 165 bp from the 5' end caused a sevenfold increase in expression of CAT. Within these 165 bp, a minimal 48-bp region was sufficient to down regulate the expression of a simian virus 40/CAT fusion plasmid. The 48-bp negative element consists of 7-bp dyad symmetry elements separated by 27 bp. The rightmost half of the dyad symmetry element partially overlaps a region which has a 14-of-15-bp homology to the human cytoskeletal gamma-actin promoter.

Evaluation of HemoQuant test and enteroclysis in estimating the sites of obscure gastrointestinal bleeding

The HemoQuant test includes the measurement of total fecal hemoglobin (Hb) or porphyrin derived from heme, and of intestinal converted fraction (ICF) which is the performed porphyrin probably by bacteria during enterocolic transit. The mean +/- SD of HemoQuant in 31 healthy subjects was 0.57 +/- 0.49 mg Hb/g stool, values above 2 mg Hb/g stool are considered to be positive. In patients with upper GI bleeding (n = 44), small bowel bleeding (n = 11) and large bowel bleeding (n = 16), the ICF ranged 0.03-23%, 0.09-20.20% and 0.35-11.0%, respectively. There was major overlap in individual ICF due to some influencing factors such as the quantity of fecal blood and the enterocolic transit. We conclude that HemoQuant is a sensitive assay for detection of fecal occult blood, but ICF is not helpful in estimating the anatomic site of bleeding. Seventy-one patients with GI bleeding of obscure origin underwent enteroclysis. The results showed 77.5% had definite lesions in the small bowel, but 22.5% still were undefined. It is suggested that enteroclysis should be performed without delay if upper and lower GI endoscopic studies are negative.

[A study on the male DNA special restricted fragment of bovine]

Bkm, which is related to sexes, is a satellite DNA of the female snake. After the genomic DNA of bovine was digested by Pst I, it was hybridized with Bkm sequence probe (p184) and subcloned in the vector pUC19. Recombinants were identified by the colony in situ and Southern blot hybridization. When we determined genomic DNA of bovine using the male DNA fragment, it was observed that the pattern of hybridization was different because of different sexes. The results showed that we could identify the sex of bovine by Southern blot hybridization with recombinants of male DNA special restricted fragment of bovine origin.

Evidence for reduced fibrinolytic activity in unstable angina at rest. Clinical, biochemical, and angiographic correlates

BACKGROUND

The goal of this study was to evaluate the role of the fibrinolytic system in patients with unstable angina at rest associated with transient electrocardiographic changes.

METHODS AND RESULTS

Tissue plasminogen activator activity in plasma was comparable among patients with unstable angina (n = 17), patients with stable exertional angina (n = 10), and control patients with normal coronary arteriograms (n = 8). In contrast, plasminogen activator inhibitor-1 (PAI-1) activity in plasma was elevated in the unstable angina group (21.67 +/- 9.52 AU/ml) as compared with either the stable angina group (12.01 +/- 7.06 AU/ml, p less than 0.02) or the controls (12.49 +/- 8.54 AU/ml, p less than 0.02). Coronary angiography performed within 24 hours after the last anginal episode showed a similar extent of coronary artery disease in the unstable and stable angina groups. However, intracoronary thrombi were observed in eight patients in the unstable angina group while no thrombus was noted in the stable angina group (chi 2 = 7.22, p less than 0.01).

CONCLUSIONS

We conclude that patients with unstable angina at rest have a reduced fibrinolytic activity and an increased incidence of intracoronary thrombi. It is postulated that elevated PAI-1 activity in the presence of coronary arterial wall injury may be an important factor leading to the development of acute coronary syndromes.