Protein engineering on subtilisin E

Protein engineering was carried out by site-directed and random mutagenesis on subtilisin E gene. Four mutants were obtained. They are M222A; M222A, N118S; M222A, N118S, Q103R; and M222A, N118S, Q103R, D60N. The mutant genes were recombined in pBE-2, an E. coli-B. subtilis shuttle vector, and transformed into B. subtilis DB104, an alkaline and neutral proteinase deficient strain. The subtilisin E mutations obtained from their gene expressions were purified. The properties of these mutants showed that the M222A mutation made the enzyme resistant to oxidation, N118S mutation increased the thermal stability, while Q103R and D60N mutations enhanced the specific activity of the enzyme but decreased the thermal stability and, in particular, D60N mutation caused the enzyme to be very unstable. The IEF-PAGE showed that the wild type and M222A mutant had the same pI of 8.92, while those of double mutant, triple mutant, and quadruple mutant were 8.88, 9.10, and 9.17, respectively. The optimum pH range was 7.5-9.5 for suc-AAPF-pNA substrate and was 10-12 for casein substrate.

Characterization of the tumor invasion area in the rat intracerebral glioma

Tumor cell invasion surrounding intracerebrally implanted tumors in rats was studied by comparing the results of cerebral microangiography, fluorescence imaging of blood-brain barrier (BBB) disruption and histopathology. Each comparison was on subsequent sections taken from an initial 1 mm coronal slice of brain taken through the cell injection site containing tumor using the RT-2 glioma model. Tumor extension was assessed at 3, 5, 7 and 9 days after tumor implantation. Analysis of the brain adjacent to tumor shows that the actual tumor cell invasion area is greater than the area of BBB disruption at later stages of tumor growth and the extent of tumor vascularization lies well within the area defined by the extent of tumor cell invasion. Furthermore, this study found that the size of the area of tumor cell invasion remains relatively stable in proportion to the solid tumor mass at various stages of growth such that the area of tumor invaded brain was approximately 2.5 times greater than the area outlined by solid tumor mass. We conclude that measurement of the solid tumor mass, tumor vascular area and region of blood-brain barrier disruption due to tumor, grossly underestimate the total tumor volume. Therapies aimed at controlling glial tumor growth must, therefore, include normal appearing regions of brain peripheral to the abnormal region defined as tumor and tumor invaded brain as defined by radiographic and imaging studies.

[High-dose chemotherapy supported by peripheral blood stem cells to treat intermediate--and high-grade non-Hodgkin's lymphomas]

In this study, 16 eligible patients with intermediate and high-grade non-Hodgkin's lymphoma were treated with a new high-dose DHACT regimen supported by rhG-CSF and peripheral blood stem cell (PBSC) rescue. PBSC were mobilized by rhG-CSF or rhGM-CSF. Single leukapheresis was performed and the PBSC were then frozen in liquid nitrogen. CFU-GM clonogenic assay for mononuclear cells and resuscitated progenitor cells done to calculate how many progenitor cells were alive after freezing. The DHACT chemotherapy was composed of carboplatin 600 mg/m2 on d1, Ara-C 1500 mg/m2 on d2, VM-26 100 mg/m2 on d3, 4, and dexamethasone 40 mg/d, on d1-4. Autologous PBSC was reinfused after 24 to 48 hours of chemotherapy. Recombinant human G-CSF at 300 micrograms administered daily on 2 successive days when the absolute neutrophil count was greater than 1 x 10(9)/L. Other supportive care procedures were standard for the unit. The median amount of PBSC reinfused into a patient was 0.9 x 10(8)/kg. The recovery rate of CFU-GM was 78% after cryopresevation. Within 7 to 9 days after high-dose DHACT chemotherapy, the WBC count and the platlet count arrived nadir, and then rose gradually with rhG-CSF injection. The median time for WBC count from nadir to > or = 1 x 10(9)/L was 4 days, and that for platelet count from nadir to > or = 50 x 10(9)/L was 7 days. Nine patients achieved complete remission and 5 patients achieved partial remission. The median follow-up on survival was 9 months. High-dose DHACT regimen supported by rhG-CSF and PBSC rescue is a safe and effective treatment for patients with advanced intermediate and high-grade non-Hodgkin's lymphoma.

Presenilin-1 polymorphism in patients with Alzheimer's disease, vascular dementia and alcohol-associated dementia in Japanese population

We investigated the genetic association between intronic polymorphism in Presenilin-1 (PS-1) gene and patients with various types of dementia such as Alzheimer's disease (AD), vascular dementia (VD) and alcohol associated dementia (ALD), in Japanese population. Homozygosity for allele 1 of the PS-1 polymorphism was significantly increased in late-onset sporadic AD, but not in early-onset sporadic AD, familial AD, VD and ALD. When late-onset sporadic AD patients were divided on the basis of apolipoprotein E (APOE) genotype, homozygosity for the allele 1 of the PS-1 polymorphism was significantly increased in patients with late-onset sporadic AD without APOE epsilon 4 allele, but not in those with APOE epsilon 4 allele. Intronic mutation in PS-1 gene may be specific and one of the genetic risk factor for late-onset sporadic AD.

Role of intracardiac angiotensin II in cardiac dysfunction of rat during septic shock

OBJECTIVE

To observe changes in the content of myocardial angiotensin II and its role in cardiac dysfunction of rat during septic shock.

METHODS

Septic shock model was produced by cecal ligation and puncture (CLP) operation on rats. Experimental rats were given captopril 15 mg.kg-1/d per os for 3 days before CLP operation. Mean blood pressure and left ventricular pressure were recorded. Myocardial angiotensin converting enzyme (ACE) activities were determined by a fluorometric assay and myocardial angiotensin II content was measured by radioimmunoassay. Highly purified membrane of sarcoplasmic reticulum (SR) was prepared from rat hearts. Assays were made of ATP-dependent Ca2+ uptake by cardiac SR and (3H) ryanodine binding to SR.

RESULTS

Myocardial angiotensin II content increased by 51.5% (P < 0.01) at the 18th hour post CLP, meanwhile there was a decrease in left ventricular +/- dp/dtmax value and the impairment in Ca2+ uptake and (3H) ryanodine binding to cardiac SR. Preliminary administration of captopril reduced myocardial ACE activity and angiotensin II content, but increased left ventricular +/- dp/dtmax value. In comparison to shock group, the initial rate and the capacity of SR Ca2+ uptake were increased by 120% (P < 0.01) and 33.9% (P < 0.05), the Bmax value of (3H) ryanodine binding to SR was also elevated, while the Kd value remained unchanged.

CONCLUSIONS

The elevated intracardiac angiotensin II, resulting from the activation of myocardial ACE during sepsis, probably serves as one of the important mediators participating in the pathogenesis of heart failure: the effects of angiotensin II may be associated with the disturbance of Ca2+ transport function of cardiac SR.

[Effects of Peucedanum praeruptorum extractum on blood pressure, left ventricular hypertrophy and hemodynamic changes in left ventricular hypertrophied hypertensive rats]

After intragastric administration of Peucedanum praeruptorum (PPE) 0.6 g/100 g body weight, the blood pressure was decreased significantly in both the normal and the left ventricular hypertrophied hypertensive (LVH) rats. The PPE could still prevent the formation of the left ventricular hypertrophy in renovascular hypertensive rats, the ratio of weight of left ventricular over the weight of body was reduced markedly than that of the LVH group, and was nearly the same of the sham-operated group. The PPE could improve both the systolic and diastolic function than that of the LVH group in the isolated heart, especially, the flow of the coronary artery was increased significantly.

Distribution of 5S and 18S-28S rDNA loci in a tetraploid cotton (Gossypium hirsutum L.) and its putative diploid ancestors

The most widely cultivated species of cotton, Gossypium hirsutum, is a disomic tetraploid (2n=4x=52). It has been proposed previously that extant A- and D-genome species are most closely related to the diploid progenitors of the tetraploid. We used fluorescent in situ hybridization (FISH) to determine the distribution of 5S and 18S-28S rDNA loci in the A-genome species G. herbaceum and G. arboreum, the D-genome species G. raimondii and G. thurberi, and the AD tetraploid G. hirsutum. High signal-to-noise, single-label FISH was used to enumerate rDNA loci, and simultaneous, dual-label FISH was used to determine the syntenic relationships of 5S rDNA loci relative to 18S-28S rDNA loci. These techniques provided greater sensitivity than our previous methods and permitted detection of six new G. hirsutum 18S-28S rDNA loci, bringing the total number of observed loci to 11. Differences in the intensity of the hybridization signal at these loci allowed us to designate them as major, intermediate, or minor 18S-28S loci. Using genomic painting with labeled A-genome DNA, five 18S-28S loci were localized to the G. hirsutum A-subgenome and six to the D-subgenome. Four of the 11 18S-28S rDNA loci in G. hirsutum could not be accounted for in its presumed diploid progenitors, as both A-genome species had three loci and both D-genome species had four. G. hirsutum has two 5S rDNA loci, both of which are syntenic to major 18S-28S rDNA loci. All four of the diploid genomes we examined contained a single 5S locus. In g. herbaceum (A1) and G. thurberi (D1), the 5S locus is syntenic to a major 18S-28S locus, but in G. arboreum (A2) and G. raimondii (D5), the proposed D-genome progenitor of G. hirsutum, the 5S loci are syntenic to minor and intermediate 18S-28S loci, respectively. The multiplicity, variation in size and site number, and lack of additivity between the tetraploid species and its putative diploid ancestors indicate that the behavior of rDNA loci in cotton is nondogmatic, and considerably more complex and dynamic than previously envisioned. The relative variability of 18S-28S rDNA loci versus 5S rDNA loci suggests that the behavior of tandem repeats can differ widely.

Separation of enantiomers of drugs by capillary electrophoresis. III. Beta-cyclodextrin as chiral solvating agent

Enantiomer separation by capillary zone electrophoresis was studied for a set of 34 chiral drugs. Keeping the concentration of beta-cyclodextrin as a chiral solvating agent as constant as possible led to the separation of seven enantiomeric pairs. Carvedilol, Tetryzoline, Tropicamide and Zopiclone gave a baseline separation, Chlorphenamine, Ketamine, and Orciprenaline a partial separation. Statistical analysis revealed that the best separation factors were observed for a medium degree of interaction with the cyclodextrin. A theory explaining this effect provides a helpful guideline for further optimization.

Evidence of hypoxia-inducible factor-1 in vascular endothelial and smooth muscle cells

The hypoxia-inducible element (HIE-1), a 50-bp region just 3' to the human erythropoietin gene, has been found to regulate transcription in cells that do not ordinarily synthesize erythropoietin. We hypothesized that the HIE-1 and associated protein factors may have a role in transcriptional regulation in hypoxic vascular tissues. Therefore, tissues of vascular origin were grown in culture and exposed to hypoxia (1% 02, 5% CO2, balance N2) or normoxia (21% O2, 5% CO2). Human microvascular endothelial cells (HMEC-1) studied with electrophoretic mobility shifting demonstrated that HIE-1 was bound to a protein induced by hypoxia in these cells. HMEC-1 and rat aortic smooth muscle cells (RASM) were transfected with the vector pGL2-HIE-1. HMEC-1 reporter gene expression was 3.7 +/- 0.5-fold increased at 12 hours and 3.7 +/- 1.3-fold increased at 24 hours by hypoxia. RASM reporter gene expression was 18.6 +/- 6.5-fold (SEM) increased at 12 hours and 2.0 +/- 0.7-fold increased at 24 hours by hypoxia. These findings provide indirect evidence of a hypoxia-inducible factor in vascular cellular transcriptional regulation.

Analysis of amyloid precursor protein mRNAs in skin fibroblasts in Down's syndrome

We examined amyloid precursor protein (APP) mRNAs expression in skin fibroblasts from Down's syndrome (DS) patients of different ages to determine the time of occurrence of abnormal splicing. The ratio of APP770 + 751 mRNA to APP695 mRNA (APP770 + 751/695) was significantly increased in the young DS group and adult DS group compared with the age-matched control groups (p < 0.01, p < 0.05), but no significant increase was observed in the aged DS group compared with the age-matched control group. These findings suggest that metabolic abnormalities of the APP gene occur at a very early stage of DS, at a mean age of about 5 years. Therefore, metabolic abnormalities of the APP gene are considered to appear at a very young age also Alzheimer's disease (AD). In this study, we confirmed that examination of the APP gene in skin fibroblasts might be useful for early diagnosis of AD.

Effects of Arg-Gly-Asp-Ser on Ca2+ transport of myocardial sarcoplasmic reticulum in rat septic shock

AIM

To study the effects of Arg-Gly-Asp-Ser (RGDS), a synthetic short peptide of fibrinogen degradation, on the Ca2+ transport function of cardiac sarcoplasmic reticulum in rat septic shock.

METHODS

RGDS 5 mumol.kg-1 was injected i.v. at 4 h and 14 h after cecal ligation and puncture (CLP) operation on rats. Highly purified membrane of sarcoplasmic reticulum (SR) was prepared from rat hearts. Assays were made of ATP-dependent Ca2+ uptake by cardiac SR and [3H] ryanodine binding to SR.

RESULTS

The initial rate and the capacity of SR Ca2+ uptake were increased by 104% (P < 0.01) and 12% (P < 0.05), respectively, paralleled by an increase in Ca(2+)-ATPase activity and a decrease in calcium accumulation of myo- cardium of septic rats, whereas the Bmax and Kd values of Ca2+ activated [3H]ryanodine binding to SR were unaffected after RGDS administration.

CONCLUSIONS

The results indicated that RGDS have cardioprotective effects of maintaining Ca2+ homeostasis of cardiac myocytes by enhancing SR Ca2+ uptake in rat septic shock.

C5a peptidase alters clearance and trafficking of group A streptococci by infected mice

Group A streptococcal C5a peptidase (SCPA) specifically cleaves the human serum chemotaxin C5a at the polymorphonuclear leukocyte (PMNL) binding site. This study tested the proposal that SCPA contributes to virulence by retarding the influx of inflammatory cells and clearance of streptococci during the first few hours after infection. To investigate the specific contribution of SCPA to the virulence of group A streptococci, scpA insertion and deletion mutants were created by directed plasmid insertion into scpA and gene replacement. The precise locations of insertion and deletion mutations were confirmed by PCR and DNA sequence analysis. The impact of mutation on virulence was investigated with a mouse air sac model of inflammation. Experiments evaluated clearance of streptococci from the air sac within 4 h after infection. SCPA- streptococci were cleared more efficiently than wild-type bacteria. Localization of streptococci in lymph nodes and spleens of infected mice revealed a significant difference between mutant and wild-type streptococci. PMNLs and other granulocytes that infiltrated the air sac were quantitated by single-color flow cytometry. The total cellular infiltrate was greater and PMNLs dominated the granulocytic infiltrates of air sacs inoculated with SCPA- mutant bacteria. The data obtained are consistent with the possibility that SCPA- streptococci are initially cleared from the site of infection primarily by PMNLs. Moreover, mutant and wild-type streptococci followed different paths of dissemination. SCPA- bacteria were transported to lymph nodes, whereas wild-type streptococci avoided transport to the lymph nodes and rapidly spread to the spleen.

Microsomal formation of S-nitrosoglutathione from organic nitrites: possible role of membrane-bound glutathione transferase

The formation of S-nitrosoglutathione (GSNO) from amyl nitrite and n-butyl nitrite was studied in rat liver microsomes, employing N-ethylmaleimide (MalNEt) as an activator and indomethacin as an inhibitor of microsomal glutathione S-transferase (GST). Rates were compared with GST activity measured with 1-chloro-2,4-dinitrobenzene (CDNB) as a substrate. MalNEt stimulated GST activity and the formation of GSNO from amyl nitrite and n-butyl nitrite about 10-fold. Increasing concentrations of indomethacin inhibited both reactions in parallel. N-Acetyl-L-cysteine but not L-cysteine could substitute for GSH. It is concluded that rat liver microsomal GST catalyses the formation of GSNO from amyl nitrite and n-butyl nitrite. The activity of the MalNEt-stimulated microsomal GST is calculated to be about 17 units/mg of enzyme with the alkyl nitrites and about 16 units/mg of enzyme with CDNB as a substrate, assuming that 3% of microsomal protein is GST. These rates are comparable with those obtained for cytosolic GSTs. Thus microsomal GST may play a significant role in the metabolism of alkyl nitrites in biological membranes.

[Effects of m-Nif and Nif on left ventricle hypertrophy in rats induced by partial ligation of abdominal aorta]

Partial ligation of the abdominal aorta of rats was adopted to induce left ventricle hypertrophy (LVH). The effects of m-nifedipine (m-Nif) and nifedipine (Nif) on prevention of hypertrophy and the possible mechanism were investigated. The wet weights of the left ventricle (WWLV) of the LVH group were increased compared with those of the sham operated group. After treatment with m-Nif and Nif for 4 wks, the WWLV decreased by 25% +/- 9% and 16% +/- 9%, respectively. The pressure-volume (P-V) curve of the hypertrophied group was markedly elevated, which means that the myocardial compliance was decreased, and the stiffness coefficient of the hypertrophied group was significantly elevated than that of the sham operated group, but the groups treated with m-Nif or Nif were significantly improved. The characteristics of the left ventricular myocardial DHP binding sites were studied. The results showed that the Kd and the Bmax were similar in the m-Nif, Nif and hypertrophied groups, but the total number of the DHP receptors (TNR) of the LVH group was markly increased than that of the sham operated group, but the TNR of the m-Nif and Nif groups were the same as that of the sham operated group. These results suggest that the effects of m-Nif and Nif on preventing cardiac hypertrophy and improving myocardial compliance may be related to their depressing the TNR of DHP.

Tangential migration of luteinizing hormone-releasing hormone (LHRH) neurons in the medial telencephalon in association with transient axons extending from the olfactory nerve

During embryonic development, luteinizing hormone-releasing hormone (LHRH) neurons migrate to the brain from the medial olfactory epithelium through the olfactory nerve. LHRH neurons enter the brain and migrate tangentially along the medial edge of the telencephalon in close association with a neural cell adhesion molecule (N-CAM) enriched fiber bundle. In the current work we wished to determine whether this N-CAM enriched fiber bundle is an extension of the olfactory nerve. Ablation experiments, immunocytochemistry and diI implants all suggest that LHRH neurons migrate in association with a very small subset of transient N-CAM enriched neuronal processes which extend out of the olfactory nerve proper to the septal-preoptic area.

[Effects of taurine and enalapril on blood pressure, platelet aggregation and the regression of left ventricular hypertrophy in two-kidney-one-clip renovascular hypertensive rats]

In two-kidney-one-clip (2k-1c) renovascular hypertensive rats, the blood pressure, left ventricular weight/body weight (LVW/BW) ratio and blood platelet aggregation were increased significantly. Enalapril (Ena) 6 mg . kg-1 . d-1 ig 9 wk and Taurine 30 mg . kg-1 . d-1 ig 9 wk can not only decrease the high blood pressure, LVW/BW ratio, but also the blood platelet aggregation induced by ADP or thrombin, though still different from that of the normal group. When the 2k-1c renovascular hypertensive rats were treated with both Ena and Tau, the blood pressure and blood platelet aggregation were decreased to the same as that of the normal group, and the LVW/BW ratio was also lowered markedly, though still higher than that of the normal group. These results show that both Ena and Tau can reverse the left ventricular hypertrophy, decrease the blood pressure and suppress the blood platelet aggregation in 2k-1c renovascular hypertensive rats. When treated with both drugs, the effects can be improved. It suggests that the two drugs can enhance the effects when used together, and that they may be two good agents for treatment of hypertension.

[Impaired calcium uptake by cardiac sarcoplasmic reticulum and its underlying mechanism during rat septic shock]

The underlying mechanism of Ca2+ uptake function of cardiac sarcoplasmic reticulum (SR) was investigated in the rat septic shock model produced by cecal ligation and puncture (CLP). The results are as follows. During the early phase of sepsis, the initial rate of ATP-dependent Ca2+ uptake by SR was decreased, while both the capacity of Ca2+ uptake and the activity of Ca(2+)-ATPase were unaffected. In the late sepsis, the impairment in SR function was even greater as the initial rate and the capacity of Ca2+ uptake by SR were significantly decreased, and this was paralleled by a reduction in Ca(2+)-ATPase activity. Although Ca2+ affinity (Km value) to calcium pump and the A0.5 values for Mg2+ and ATP activation on the Ca2+ uptake rate were unchanged, during sepsis the phosphorylation of SR vesicles by adding of catalytic subunit of the cAMP-dependent protein kinase (PKA), calmodulin, or the fragment of PKC into Ca2+ uptake buffer, failed to stimulate Ca2+ uptake activities of SR isolated from early or late septic rats. These data suggest that depression of cardiac SR function is aggravated as sepsis develops, the impairment of SR Ca2+ uptake is possibly based on a mechanism of defective phosphorylation of SR rather than the ionic and energic regulatory actions of Ca2+, Mg2+, ATP on cardiac SR.

[Altered ryanodine receptor of rat cardiac sarcoplasmic reticulum and its underlying mechanism during septic shock]

The present study was undertaken to observe the changes of Ryanodine receptor of cardiac junctional sarcoplasmic reticulum (SR) in relation to membrane lipid microenvironment alteration during septic shock. The results showed that the Bmax for 3H-ryanodine binding to cardiac junctional SR was decreased by 41.3% (3.9 +/- 0.1 vs. sham 6.6 +/- 0.7 pmol/mg, P < 0.01) while the Kd value was unaffected during late septic shock (CLP 18 h). Ca2+ activated 3H-ryanodine binding significantly and reached a saturation value when Ca2+ concentration was 5 x 10(-5) mol/L, while the S0.5 and the Hill coefficient values remained unchanged during septic shock. Caffeine, ATP, and AMP-PCP activated while Mg2+, ruthenium red inhibited 3H-ryanodine binding in both groups but the A0.5 (concentration requires for half maximum activation) and the IC50 (concentration requires for half-maximum inhibition) for the above mentioned activators and inhibitors, were respectively unaffected during septic shock. Digestion of cardiac SR isolated from control rats with phospholipase A2 inhibited 3H-ryanodine binding, which could be dramatically recovered by the incorporation of phosphatidylcholine (PC), or phosphatidylserine (PS), or phosphatidylethanolamine (PE) into the isolated cardiac SR. Incorporation of above phospolipids into SR isolated from septic rats reversed shock-induced inhibition of 3H-ryanodine binding. It is concluded that the mechanism responsible for the inhibition of 3H-ryanodine binding of junctional SR during septic shock may be related to modification of membrane lipid microenvironment in response to PLA2 overactivation during septic shock.

An extensive subfrontal approach to the lesions involving the skull base

A modification of the transbasal approach of Dorome called extensive subfrontal approach and the surgical results with this approach in 22 cases are presented. Bilateral frontal craniotomies incorporated with the removal of orbital ridges and part of the orbital roofs were fashioned en bloc. It may give rise to good exposure of the midline lesions of the anterior, middle and posterior skull base, minimizing the need for the retraction of frontal lobes. There was no surgical mortality in this series of cases. Of the 20 cases with tumors, total resections were achieved in 11 cases, subtotal or large resections in 4 cases and partial resection in one case. Two patients with spontaneous rhinorrhea were successively treated surgically. 21 patients had a follow-up with a time ranging from 1-11 years (a mean of 3 years). 15 patients resumed their jobs with no evidence of recurrence of the original disease, and 5 patients able to live self-care. One patient with an olfactory neuroblastoma died 3 years after the operation owing to relapse of the tumor.