Crystallization and preliminary X-ray analysis of earthworm fibrinolytic enzyme component A from Eisenia fetida

Earthworm fibrinolytic enzyme component A, a protein which functions both as a direct fibrinolytic enzyme and a plasminogen activator, was purified from the earthworm Eisenia fetida. Diffraction-quality single crystals of the protein were grown by the hanging-drop vapour-diffusion technique with ammonium sulfate as a precipitant. The crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 40.6, b = 127.5, c = 129.2 A and three molecules per asymmetric unit. The data set reached a resolution of 1.95 A.

Development of an affordable diaphragmatic pump for cardiopulmonary bypass: an in vivo evaluation

A new diaphragmatic pump (L-Y pump) and its drive unit were developed in our institute. The pump has a priming volume of 80 ml. The pump housing is 72 mm in diameter and 42 mm in height. Its total weight is 139 g. To assess and confirm the function and controllability of this pump, comparative studies of cardiopulmonary bypass (CPB) with L-Y pump (group A) and conventional roller pump (Group B) were performed using dogs. Both pumps provided pump flow of 90 to 100 ml/kg/min. The hemodynamics of both groups were stable and within the normal range. No leakage or thrombus formation was observed in the L-Y pump. All biochemistry data showed no significant differences between the 2 groups. This data demonstrated low plasma-free hemoglobin levels in the L-Y pump group; after 120 min of CPB, mean plasma free hemoglobin levels were 48.7 +/- 8.6 mg/dl in the roller pump group and 21.4 +/- 7.1 mg/dl in the L-Y pump group, and minimal hemolysis was indicated. In conclusion, this L-Y pump and its controller system might be useful for CPB in terms of its low hemolysis and good pump quality. This pump demonstrated easy manipulation, good controllability, and provided a sufficient pulsatile flow. This pump is suitable not only for CPB, but also as a long-term circulatory support system.

Modeling and predicting selected immunological effects of a chemical stressor (3,4-dichloropropionanilide) using the area under the corticosterone concentration versus time curve

Many chemicals and drugs can induce a neuroendocrine stress response that can be immunosuppressive. Mathematical models have been developed that allow prediction of the immunological impact of such stress responses in mice on the basis of exposure to the important stress-related mediator corticosterone. The area under the corticosterone concentration vs. time curve (AUC) has been used as an indicator of cumulative corticosterone exposure in these modeling studies. In the present study, an immunotoxicant known to induce a stress response, 3,4-dichloropropionanilide (propanil), was evaluated to determine if corticosterone AUC values are related to suppression of immunological parameters in mice treated with this chemical. Linear relationships between corticosterone AUC values and suppression of the following parameters were noted in B6C3F1 female mice: thymus cellularity and thymus subpopulation percentages, splenic subpopulation percentages, natural killer cell activity, MHC class II protein expression, and IgG1 and IgG2a antibody responses to antigen. Linear models derived in previous studies using mice treated with exogenous corticosterone or with restraint stress effectively predicted the immunological effects of 3, 4-dichloropropionanilide on the basis of corticosterone AUC values. The models derived using immobilization stress were more effective (r(2) for observed vs. predicted = 0.90) than the models derived using mice treated with exogenous corticosterone (r(2) for observed vs. predicted = 0.65). This was expected, because most stressors induce a variety of immunomodulatory mediators, not just corticosterone. These findings have implications for risk assessment in immunotoxicology.

The p53 codon 72 polymorphism and lung cancer risk

The p53 tumor suppressor gene frequently is mutated in many forms of human carcinomas. A common polymorphism occurs at codon 72 of exon 4, with two alleles encoding either arginine (CGC) or proline (CCC). This p53 polymorphism reportedly is associated with lung cancer susceptibility. However, not all investigations have been consistent, and this hypothesized association remains controversial. We tested the hypothesis that the Pro/Pro genotype is associated with increased lung cancer risk in a large case-control study of lung cancer that included 482 cases and 510 controls from the Massachusetts General Hospital in Boston, Massachusetts. DNA from peripheral blood samples was examined by PCR-RFLP. Pro/Pro homozygotes were found more frequently in adenocarcinomas (cases, 16.4%; controls, 12.0%; P = 0.03). The prevalence of the Pro/Pro homozygous genotype increased in frequency with increasing pack-years of smoking. The combined susceptible genotype homozygous Pro/Pro and heterozygous Arg/Pro was associated with a 1.45-fold higher risk of adenocarcinoma compared with Arg/Arg genotype (95% confidence interval = 1.01-2.06; P = 0.04) after adjustment for relevant variables. Lung adenocarcinoma risk increased with the presence of one or both variant alleles across smoking strata. In addition, at each level of smoking (except nonsmoker and light smoker), the risk associated with smoking was higher for the population with the combined variant (Arg/Pro + Pro/Pro) genotype. The risk for the combined genotype was associated with tobacco exposure status. In conclusion, the codon 72 germ-line polymorphism (Arg/Pro) of the common tumor suppressor gene p53 contributes to heritable susceptibility for smoke-induced lung adenocarcinoma. The modifications by p53 polymorphism and pack-years resulted in an increased risk of the susceptible genotype to lung adenocarcinoma. The p53 gene may modulate the response to environment carcinogens and thereby affect the risk of developing lung adenocarcinoma.

[The research and manufacture of the pneumatic left ventricular assist pump]

The manufacturing methods and testing results of the pneumatic left ventricular assist pump(L-Y pump) are introduced in this paper. The results demonstrate that L-Y pump is reliable, biocompatible and in keeping with the clinical requirements.

Recognition of a sequestered self peptide by influenza virus-specific CD8+ cytolytic T lymphocytes

The Ag receptors on CD8+ CTL recognize foreign antigenic peptides associated with cell surface MHC class I molecules. Peptides derived from self proteins are also normally presented by MHC class I molecules. Here we report that an H-2Kd-restricted murine CD8+ CTL clone directed to an influenza hemagglutinin epitope can recognize a peptide derived from the murine mitochondrial aconitase enzyme in association with H-2Kd molecules. Surprisingly, this self peptide is not normally displayed on the cell surface associated with the restricting MHC class I molecule. Several lines of evidence suggest that this self peptide, although requiring association with the Kd molecule for CTL recognition, is not associated with this or other MHC class I allele under physiologic conditions in intact cells. Rather, it is sequestered in the cytoplasm associated with a carrier protein and is released only upon cell disruption. These results suggest a means of restricting the entry of self peptide into the class I pathway. In addition, this finding raises the possibility that self peptides sequestered within the cell can, after release from damaged cells, interact with MHC class I molecules on bystander cells and trigger autoimmune injury by virus-specific CTLs during viral infection.

A method for processing fluorescent labelled tissue into methacrylate: a qualitative comparison of four tracers

A technique for preserving fluorescence in retrogradely labelled neurons embedded in resin was developed. Four retrograde tracers were tested, Fast Blue (FB); Diamidino Yellow (DY); tetramethylrhodamine dextran (fluoro-ruby) (TMRD) and fluorescein dextran (fluoro-emerald) (FD). These tracers were applied to the cut end of the sciatic nerves in rats either by: (a) direct application of tracer crystals, or (b) dipping the nerve into an aqueous solution containing the tracer. Each lumbar spinal cord was removed and dehydrated by one of two methods: (a) conventional alcohol dehydration, or (b) dehydration through a graded series of aqueous methacrylate infiltration solutions (inert dehydration). Specimens were embedded in methacrylate and horizontal sections cut. The location of labelled motoneurons was mapped using a fluorescence microscope. Direct application of tracer crystals labelled more motoneurons than dipping. Fast Blue labelled considerably more motoneurons than tetramethylrhodamine. Labelling by all tracers was retained following methacrylate embedding. Fast Blue and Diamidino Yellow required inert dehydration, while tetramethylrhodamine dextran and fluorescein dextran were preserved using conventional dehydration. These results indicate that tissue labelled with commonly used fluorescent tracers can be processed and embedded in methacrylate, thereby permitting quantitative analysis by modern stereological methods.

Quantitative relationships between the suppression of selected immunological parameters and the area under the corticosterone concentration vs. time curve in B6C3F1 mice subjected to exogenous corticosterone or to restraint stress

The neuroendocrine response to stressors increases the concentration of several endogenous mediators, some of which are immunosuppressive. However, quantitative aspects of these effects have been overlooked. Although it should be possible to predict the degree of suppression of particular immunological functions by measuring the concentrations of stress-related mediators such as corticosterone, this cannot be done with data presently available. This study was designed to develop regression models to predict the relationship between the area under the corticosterone concentration vs. time curve (AUC) and two immunological parameters. Models were developed using mice treated with exogenous corticosterone and mice subjected to various periods of restraint stress. The latter treatment was included to determine if the effects of corticosterone were different from those of corticosterone in association with the other mediators induced in a restraint-stress response. Models relating corticosterone AUC to expression of MHC class II proteins on splenocytes were very similar, whether the corticosterone was exogenous or produced as part of a restraint-stress response. This was also true for splenic natural killer (NK) cell activity. However, MHC class II expression was more sensitive to the effects of corticosterone or restraint than was NK cell activity. The corticosterone and restraint models predicted the previously published effect of a chemical stressor (ethanol) on MHC class II expression, but neither model predicted the suppression of NK cell activity by ethanol. These results have mechanistic implications, which are discussed in the context of previous studies. The quantitative models described here should be useful in determining and predicting the stress-related portion of chemical-induced immunosuppression. In addition, these models provide quantitative data essential for a complete understanding of stress-induced immunosuppression.

Autocrine transforming growth factor alpha provides a growth advantage to malignant cells by facilitating re-entry into the cell cycle from suboptimal growth states

CBS human colon carcinoma cells are poorly tumorigenic in athymic nude mice, whereas FET colon carcinoma cells are non-tumorigenic. Both cell lines have well differentiated properties in tissue culture. Transforming growth factor alpha (TGF-alpha) was ectopically expressed by stable transfection of a TGF-alpha cDNA under repressible tetracycline control. The TGF-alpha-transfected cells showed enhanced clonal initiation and shortened lag phase growth in tissue culture without an alteration in doubling time in exponential phase relative to untransfected cells. Furthermore, the TGF-alpha transfectants showed increased independence from exogenous growth factors in clonal growth assays and induction of DNA synthesis after release from quiescence. Growth factor independence was associated with sustained epidermal growth factor receptor activation in quiescent TGF-alpha-transfected cells and the requirement of exogenous insulin for stimulation of quiescent cells to re-enter the cell cycle. Higher cloning, reduced lag time in tissue, and the acquisition of growth factor independence for DNA synthesis without a change in doubling time of TGF-alpha-transfected cells indicate that autocrine TGF-alpha functions by facilitating re-entry into the cell cycle from sub-optimal growth states rather than promoting or controlling the proliferation of actively cycling cells. The modulation of growth regulation by autocrine TGF-alpha was associated with increased malignant properties as TGF-alpha transfectants showed increased tumorigenicity in athymic nude mice. The administration of tetracycline reversed the effects of TGF-alpha expression in these cells both in vivo and in vitro, indicating that the alterations of the biological properties were due to the expression of TGF-alpha. Since these cells are continuously grown in a completely chemically defined medium without serum supplementation, it was possible to assign the mechanism underlying the generation of growth factor independence to the replacement of a requirement for exogenous insulin in parental cells by autocrine TGF-alpha.

Models for haplotype evolution in a nonstationary population

Haplotype mapping has emerged in the past few years as a powerful tool for the fine mapping of disease genes. It is typically carried out on a sample of affected individuals from a population isolate. If the chromosome neighborhood of a disease gene is saturated with markers, then each new mutation in the population or existing mutation introduced by a population founder exhibits a unique haplotype signature at the time of its introduction. Partial disruption of these signatures by recombination can be visualized in affects and provide important clues to the location of the disease gene. The current paper models haplotype evolution with the intention of clarifying the most favorable circumstances for haplotype mapping. Comparisons with linkage mapping are stressed. For dominant diseases, both deterministic and stochastic models are suggested. Numerical examples based on Finnish population parameters illustrate the general theory in the presence of the complications of selection, mutation, and slow, exponential growth of the isolate.

Dynamic activation of endothelial nitric oxide synthase by Hsp90

Heat-shock protein 90 (Hsp90) coordinates the trafficking and regulation of diverse signalling proteins, but its precise role in regulating specific cellular targets is not known. Here we show that Hsp90 associates with endothelial nitric oxide synthase (eNOS) and is rapidly recruited to the eNOS complex by agonists that stimulate production of nitric oxide, namely vascular endothelial growth factor, histamine and fluid shear stress. Moreover, the binding of Hsp90 to eNOS enhances the activation of eNOS. Inhibition of signalling through Hsp90 attenuates both agonist-stimulated production of nitric oxide and endothelium-dependent relaxation of isolated blood vessels. Our results indicate that Hsp90 facilitates signalling mediated by growth-factor, G-protein and mechanotransduction pathways that lead to the activation of eNOS. These observations indicate that in addition to its role as a molecular chaperone involved in protein folding and maturation, Hsp90 may also be recruited to cellular targets depending on the activation state of the cell.

[A preliminary report of histological study on TMJ reconstruction with autogenous costochondral graft]

To study histologically the biological behaviour of the grafts and the reactions in the receipt area after reconstruction of temporomandibular joint (TMJ), we have reconstructed experimentally removed TMJs on purebred juvenile pigs by transplanting autogenous costo-chondral grafts. The findings of continuously survey of histologic changes in the receipt areas and the grafts showed that autogenous grafts healed well with the surrounding soft tissues, and induced the mesenchymal-like cells from the receipt region, rather than the periosteal cells which might be left, to differentiate and ossify both within and at the surface of them, and they themselves were gradually replaced by the new-formed bone; and that active osteogenesis could also be seen within the thick tissues far from the graft, which could not be the result of graft's induction. It may be concluded that the new bone, both from the induction of the graft which acts as a framework and somehow from the outside tissues, reconstructs the new condyle and determines the postsurgical growth of the mandible.

[Studies on relationship between passive smoking and lung cancer in non-smoking women]

A population-based case-control study was conducted in Beijing, as part of Sino-Monica Project, to explore etiology of lung cancer in non-smoking women. Results showed that there was certain association between passive smoking and lung cancer in non-smoking women, with an OR of 2.52, P < 0.05, and its strength also increased with cigarette-years of smoking. A statistically significant risk of lung cancer was observed in non-smoking women, as their passive cigarette-years accumulated to more than 200. Adenocarcinoma of the lung was more possibly induced by environmental tobacco smoke (ETS) (OR = 2.32, P < 0.05), and it seemed to have little relation between ETS and squamous lung cancer (OR = 1.04, P < 0.05).

Endothelial nitric oxide synthase is regulated by tyrosine phosphorylation and interacts with caveolin-1

The regulation of endothelial nitric oxide synthase (eNOS) by phosphorylation is poorly understood. Here, we demonstrate that eNOS is tyrosine-phosphorylated in bovine aortic endothelial cells (BAEC) using 32P metabolic labeling followed by phosphoamino acid analysis and by phosphotyrosine specific Western blotting. Treatment of BAEC with hydrogen peroxide and the protein tyrosine phosphatase inhibitor, sodium orthovanadate, increases eNOS tyrosine phosphorylation. Utilizing a novel immunoNOS assay, the increase in tyrosine phosphorylation is associated with a 50% decrease in the specific activity of the enzyme. Because eNOS is localized in plasmalemma caveolae, we examined if tyrosine phosphorylated eNOS interacts with caveolin-1, the coat protein of caveolae. Immunoprecipitation of eNOS from bovine lung microvascular endothelial cells resulted in the co-precipitation of caveolin-1. Conversely, immunoprecipitation of caveolin-1 resulted in the co-precipitation of tyrosine-phosphorylated eNOS. Thus, tyrosine phosphorylation is a novel regulatory mechanism for eNOS and caveolin-1 is the first eNOS-associated protein. Collectively, these observations provide a novel regulatory mechanism for eNOS and suggest that tyrosine phosphorylation may influence its activity, subcellular trafficking, and interaction with other caveolin-interacting proteins in caveolae.

[Clinical observation on child aplastic anemia treated with integrated Chinese and Western medicine]

Forty-three cases of aplastic anemia were treated with fetal blood transfusion, Chinese medicinal herbs and Vit. C. The results showed that the effective rate of the treated group was 79.1%, among them, the chronic aplastic anemia (CAA) was 88.9%, acute aplastic anemia (AAA) was 62.5%, both rates were higher than that of the control group (with western medicine alone, n = 46). The difference of treatment results between two groups was highly significant. The mechanism was that the therapy could rebuild hematopoietic function, modulate immune function and improve microcosmic environment in bone marrow so that it promoted in all aspect the recovery of hematopoietic function in organism.

Meeting the challenge of diabetic blindness in the 90's

Diabetic retinopathy is a leading cause of blindness in adults in Singapore and it is increasing in incidence. The difficulties and problems of screening for diabetic retinopathy were discussed as well as strategies laid out for overcoming this disease of national importance. Cost considerations and savings in health costs were also discussed. The authors suggested ways of instituting a nation-wide Diabetic Screening and Education programme with hospital diabetic centre based clinic as well as a mobile screening service. A five-year screening plan as well as the costs and equipment necessary for such a programme were examined.

Denervation inhibits early increase in Na(+)-H+ exchange after uninephrectomy but does not suppress hypertrophy

Na(+)-H+ exchange in the rat proximal tubule luminal membrane increases approximately 30% within 15 min after the contralateral uninephrectomy. The present study was designed to test whether altered renal sympathetic nerve outflow to the remaining kidney is the underlying mechanism of increased antiport activity and whether suppression of Na(+)-H+ antiport activity by renal denervation inhibits renal hypertrophy in the remaining kidney after uninephrectomy. Sprague-Dawley rats were divided into four groups: 1) sham operated, 2) uninephrectomized, 3) uninephrectomized with prior denervation of the remaining kidney, and 4) contralateral renal denervation. Na(+)-H+ antiport activity (brush-border vesicles), Na(+)-K(+)-ATPase activity (basolateral vesicles), and kidney weight were measured days 1-7. On days 1 and 7, Na(+)-H+ antiport activity and Na(+)-K(+)-ATPase activities were significantly greater in uninephrectomized rats. Denervation of the remaining kidney before contralateral uninephrectomy prevented the stimulation of the antiporter and Na(+)-K(+)-ATPase activity, but failed to inhibit renal hypertrophy by day 7. In separate experiments, contralateral renal denervation alone without removal of the kidney stimulated the Na(+)-H+ antiporter and Na(+)-K(+)-ATPase activity. Kidney weight, however, remained unchanged. The results demonstrate a dissociation between the activation of the Na(+)-H+ antiporter and induction of renal hypertrophy in vivo.

Maximal mydriasis evaluation in cataract surgery

We propose the maximal mydriasis test (MMT) as a simple and safe means to provide the cataract surgeon with objective and dependable preoperative information on the idiosyncratic mydriatic response of the pupil. The MMT results of a consecutive series of 165 eyes from 100 adults referred for cataract evaluation are presented to illustrate the test's practical applications and value. The results enable the surgeon to anticipate problem eyes preoperatively so he or she can plan an appropriate and effective surgical strategy. The MMT has also improved out cost-effectiveness by cutting down unnecessary delays in the operating room and enabling better utilization of restricted costly resources.

Maximal mydriasis evaluation in cataract surgery

We propose the Maximal Mydriasis Test (MMT) as a simple and safe means to provide the cataract surgeon with objective and dependable pre-operative information on the idiosyncratic mydriatic response of the pupil. The MMT results of a consecutive series of 165 eyes from 100 adults referred for cataract evaluation are presented to illustrate its practical applications and value. The results of the MMT allows the surgeon to anticipate problem eyes pre-operatively so that he can plan his surgical strategy more appropriately and effectively. Conversely, the surgeon can also appropriately and confidently plan surgical procedures where wide pupillary dilation is important. The MMT has also helped improve our cost-effectiveness by cutting down unnecessary delays in the operating room and enabling better utilisation of restricted costly resources.

Sequential argon-YAG laser iridotomies in dark irides

Laser iridotomies in dark coloured irides are associated with higher complication and failure rates. A prospective clinical study to evaluate the use of the argon and Nd:YAG laser in sequential combination for iridotomy was carried out on 20 eyes of 13 patients with dark irides. Patent iridotomies were achieved in single treatment sessions for all the eyes. Iridotomy closure was observed in one eye during a mean follow-up period of 14 months (range 6-20 months). Complications from the treatment occurred in five eyes and were minor. Total mean energy used for the argon and Nd:YAG stages respectively were a third of most studies on pure argon and Nd:YAG iridotomies. Sequential argon-YAG laser iridotomy combines most of the advantages of both laser types while avoiding some of their disadvantages. We find it a safe and effective tool for iridotomy in otherwise difficult dark irides.