[Evaluation on the effect of synthetic hydroxyapatite for drinking water defluoridation in field study]

In order to evaluate the effect of synthetic hydroxyapatite on drinking water defluoridation, a coagulative precipitation method and a flow column system was tested in the fields. The defluoridation capacity of coagulative precipitation method was 4.19 mg/g, and the method was simple on operation, but more reagents were needed with high cost for operation. The defluoridation capacity of flow column system was 6 mg/g and the saturated hydroxyapatite could be reused after regeneration. The operation of household defluoridator based on flow column system is simple, with low cost and high capacity in defloridation. The system will be applied in the fluorosis areas.

Foldable lens explantation and exchange: the reason and solution

OBJECTIVE

To report the explanation and exchange of Hydrophilic Acrylic foldable intraocular lens (IOL) on 14 patients who had visual disturbances caused by the change of transparence on optic.

METHODS

Sixteen Hydrophilic Acrylic foldable intraocular lenses from 14 patients who presented with decreased visual acuity from 6 months to 1 year after normal phacoemulsification and IOL implantation associated with extensive transparent change on optic of the lens. The lenses were explanted with the bisection technique. All the eyes were reinserted with Acrysof foldable lenses.

RESULTS

Sixteen lenses were removed successfully and exchanged with the new lens in the capsule. The posterior capsular rupture and vitreous loss were found in the first two cases. One of them had the zonulysis due to the radial tear of the anterior capsule during the enlargement of the capsular opening. The anterior vitrectomy was performed with IOL fixed on the ciliary sulcus. The visual acuity of all the patients improved obviously without posterior complication.

CONCLUSION

Foldable lens explanation with the bisection technique and exchange had a successful outcome with improvement of ocular condition.

[Expression and kinase activity of B-Raf and Raf-1 in leukemia cell lines]

OBJECTIVE

To study expression and kinase activity of B-Raf and Raf-1 kinases in several leukemia cells and normal peripheral blood lymphocytes.

METHODS

Western blot was carried out to detect expression of B-Raf and Raf-1 in peripheral blood lymphocytes and leukemia cells. Kinase activities of Raf-1 and B-Raf were analyzed by immunoprecipitation and Western blot.

RESULTS

The expression levels of Raf-1 were similar in tested leukemia cells and normal peripheral blood lymphocytes, and Raf-1 protein was all minimally tyrosine-phosphorylated. B-Raf expressed in all tested leukemia cells, but not in normal peripheral blood lymphocytes, and B-Raf was highly activated in Jurkat and K562 leukemia cells.

CONCLUSION

The abnormal expression and kinase activity of B-Raf in leukemia cells might be related to leukemia etiologically.

Protein NMR spectroscopy in structural genomics

Protein NMR spectroscopy provides an important complement to X-ray crystallography for structural genomics, both for determining three-dimensional protein structures and in characterizing their biochemical and biophysical functions.

Skeletal muscle kinetics of propofol in anaesthetized sheep: effect of altered muscle blood flow

1. The kinetics of propofol were studied in vivo in a skeletal muscle bed of the hindlimb of the anaesthetized sheep at normal and low rates of blood flow. 2. Propofol kinetics in muscle were determined during and after a 20-min i.v. infusion of propofol (10 mg min-1) via paired arteriofemoral venous blood sampling. One-and-a-half hours later, the study was repeated but with a concurrent left femoral artery infusion of adrenaline (0.004 mg min-1) to lower the muscle blood flow by vasoconstriction. 3. Muscle blood flow in the low flow state was 28% of that in the normal state. The kinetics were poorly described by a single flow-limited compartment model, but were better described by a model with a flow-limited component and a deeper distribution component. There were no significant differences in muscle retention of propofol between normal and low flow states. 4. There was an apparent arteriovenous shunt of approximately 24% of total muscle blood flow for the low flow state, but not for the normal blood flow state.

Characterization of laboratory mutants of Venturia inaequalis resistant to the strobilurin-related fungicide kresoxim-methyl

Several agricultural fungicides related to the antifungal strobilurins act as inhibitors of respiration by binding to mitochondrial cytochrome b. Two types of laboratory mutants resisting higher doses of the strobilurin-related inhibitor kresoxim-methyl were characterized for Venturia inaequalis, the causal agent of apple scab. Selection of mutagenized conidia by kresoxim-methyl yielded mutants altered in the expression of alternative respiration during the stage of conidia germination. Cytochrome b sequences were not affected in the respective mutants. Selection of conidia on media containing the alternative oxidase inhibitor salicylhydroxamic acid in addition to kresoxim-methyl yielded a highly resistant mutant distinguished by a G143A exchange in cytochrome b. The status of mitochondrial cytochrome b genes remained heteroplasmic, and mitochondria containing wild-type cytochrome b returned to high frequencies during cultivation on inhibitor-free medium. However, continuation of the selection process led to a more pronounced replacement of sensitive by mutated mitochondria. The G143A mutation of cytochrome b causing resistance of V. inaequalis to a strobilurin-related inhibitor has been reported previously for mouse mitochondria; and a permanent G143A exchange rendering naturally resistant mitochondria has been reported for the strobilurin-producing basidiomycete Mycena galopoda and for the sea urchin Paracentrotus lividus. At the corresponding position, alanine was also present in chloroplast cytochrome b6 exhibiting low binding of strobilurin-related inhibitors. The mutation of cytochrome b reported here for V. inaequalis describes the first example of a mutation in filamentous ascomycetes and is part of an assessment of resistance risks inherent to strobilurin fungicides.

The presence of humic substances and DNA in RNA extracts affects hybridization results

RNA extracts obtained from environmental samples are frequently contaminated with coextracted humic substances and DNA. It was demonstrated that the response in rRNA-targeted oligonucleotide probe hybridizations decreased as the concentrations of humic substances and DNA in RNA extracts increased. The decrease in hybridization signal in the presence of humic substances appeared to be due to saturation of the hybridization membrane with humic substances, resulting in a lower amount of target rRNA bound to the membrane. The decrease in hybridization response in the presence of low amounts of DNA may be the result of reduced rRNA target accessibility. The presence of high amounts of DNA in RNA extracts resulted in membrane saturation. Consistent with the observations for DNA contamination, the addition of poly(A) to RNA extracts, a common practice used to prepare RNA dilutions for membrane blotting, also reduced hybridization signals, likely because of reduced target accessibility and membrane saturation effects.

Muscle glucose transporter (GLUT 4) gene expression during exercise

Among the many effects of exercise is the induction of glucose transporter (GLUT 4) expression in skeletal muscle. In this review, we examine the intracellular signals that may mediate the exercise-induced increase in GLUT4 gene transcription. This induction is likely to be dependent upon intracellular calcium concentrations and the energy charge of the muscle.

[The disinfection efficiency comparison of different treatments on dental impression and gypsum casts]

OBJECTIVE

In this study, the disinfecting efficiency of five disinfecting methods to three bacterial: Staphylococcus epidermidis, Streptococcus sanguis and Bacillus subtilis were evaluated.

METHODS

Germ free impressions and gypsum casts were divided into three teams contained 16 impressions and 5 gypsum casts for each one. Each team was smeared with each one of the three bacterial solutions. Then four disinfecting methods were administrated on these impressions separately, 2% glutaraldehyde immersion, 2% glutaraldehyde spray, 5% Eric immersion, 5% Eric spray. And ozone treatment was administrated on gypsum casts. Control teams were set up. After the treatment the impressions and gypsum casts were sampled at standard sites. The colonies were counted after culture and were used to deduce the germicidal ratio as the standard of disinfecting efficiency.

RESULTS

There was no difference between the efficiencies of five disinfecting methods for Streptococcus sanguis and Staphylococcus epidermidis. But for B. subtilis, the immersion methods have the highest efficiency among the methods and the ozone treatment has the least efficiency.

CONCLUSION

2% glutaraldehyde immersion, spray, 5% Eric immersion, spray are all effective disinfecting methods for impressions and ozone treatment is an effective method in disinfecting the gypsum casts.

Plasma endothelin-1 levels and circulating endothelial cells in patients with aortoarteritis

To investigate the correlation between plasma endothelin-1 (ET-1), circulating endothelial cells (CECs), and the disease activity in patients with aortoarteritis. In this study, radioimmunoassay was used to measure plasma levels of ET-1 in 56 patients with aortoarteritis. Circulating endothelial cell counts were also carried out as an indicator of vessel wall lesions. The plasma levels of ET-1 and CECs in the active disease patient group were significantly higher than those in inactive patient group (p<0.001). A significant positive correlation was found between plasma ET-1 levels and erythrocyte sedimentation rates (ESRs) in patients with aortoarteritis (r=0.645, p<0.001), as well as CECs (r=0.876, p<0.001). These results suggested that the ET-1 secreted during the active stages of aortoarteritis may cause constriction and proliferation of vascular smooth muscle cells, thus contributing to the pathogenesis of luminal narrowing. The increased CECs might serve as a marker of disease activity.

In vivo manipulation and continuous measurement of muscle blood flow with venous effluent sampling

1. An acute in vivo hindlimb skeletal muscle preparation was developed in anaesthetized sheep in order to facilitate studies of the effects of altered blood flow states on drug kinetics in skeletal muscle. 2. A continuous index of blood flow was recorded via ultrasonic Doppler probes on the femoral artery and vein. Skeletal muscle effluent blood was sampled via a catheter in the femoral vein proximal to the probe. Low- and high-blood flow states were achieved by direct femoral artery infusion of adrenaline (0.002-0.006 mg/min) or magnesium (0.4-1 mmol/min), which produced mean (+/-SD) stable flow states of 25+/-12 and 185+/-56% (both n = 5) of baseline, respectively. The correlation coefficients between arterial and venous Doppler frequency shifts in five sheep during and after adrenaline infusion were 0.96 (indicating these vessels probably supplied and drained common tissue). 3. The venous Doppler frequency shifts were calibrated against timed collections of the femoral vein outflow to provide estimates of the low and normal blood flow states (mean flows of 2.8+/-1.7 and 9.3+/-5.7mL/100 g per min; both n = 3) and against an indirect Kety-Schmidt method during low- and high-blood flow states (mean flows of 2.2+/-1.3 and 18.2+/-7.0 mL/100 g per min; both n = 5). There was a generally good agreement between the two methods. 4. The tissue was neither hypoxic nor acidotic in the low- or high-flow states and altering the flow produced no change in muscle oxygen consumption, suggesting the flow changes were largely due to changes in resistance vessel tone. 5. Postmortem femoral artery dye injection and dissection of stained tissues showed the artery supplied 657+/-96 g (n = 5) of skeletal muscle and 42+/-20 g (n = 5) of other tissues. 6. It is concluded that the method is suitable for sampling predominantly muscle effluent blood at low- or high-blood flow states according to experimental requirements.

[Clinical study on hemorrheologic changes for metastatic state of gastric cancer and its relationship with syndrome-type in traditional Chinese medicine]

OBJECTIVE

To explore the hemorrheologic changes of gastric cancer in various stages, and the relationship between different phases and Syndrome-types.

METHODS

Sixty-three gastric cancer patients and 30 healthy controls matching in sex and age were studied. According to the phases of tumor and the differentiation standards of deficiency and excess syndrome in TCM, the patients were divided into 6 groups: Non-metastasis (NM), lymphnode metastasis (LM), distant metastasis (DM) groups, and Deficiency (D), Excess (E), mixed deficiency and excess (DE) groups. The hemorrheology criteria including whole blood viscosity (BV), plasma viscosity (PV), hematocrit (HCT), fibrinogen (Fib), platelet count (PC), platelet aggregation rate (PAR) were measured.

RESULTS

The value of BV, PV, Fib, PC and PAR in gastric cancer groups were higher significantly (P < 0.05, P < 0.01) than those in the healthy control group, but BV, PV in the LM and DM groups were higher than those in the healthy control group significantly (P < 0.05), while difference between NM group and the healthy control group was insignificant (P > 0.05). Hypercoagulability state presented in all the three Syndrome Type groups of gastric cancer patients, but the difference in some criteria between D and E group were significant (P < 0.05, P < 0.01); and DE groups was greatly higher than D and E groups in high-shear BV, Fib and PC (P < 0.05, P < 0.01).

CONCLUSION

The value of BV, PV Fib, PC and PAR could be regarded as good referential parameters in reflecting the condition of evil excess.

[Molecular clonging of the human dimethyglycine dehydrogenase-like gene (DMGDHL1) from the sarcosinemia critical region at 9q34]

Through the analysis of EST database, we obtained one human EST (GenBank: H28856) which showed significant similarity with the partial coding sequence of rat dimethylglycine dehydrogenase gene. This EST was mapped to 9q34 due to 95.6% identity with one genomic sequence (GenBank: AC002295). A pair of primers (HRP-1/HRP-2) designed on the sequence of the EST were coupled with the primers (lambda gt10-5/lambda gt10-3) on the vector flanking cloning site respectively to amplify the 5' and 3' cDNA beyond the EST. New primers designed based on novel cDNA sequence overlapped with the sequence within EST H28856 were used for amplification with lambda gt10-5 and lambda gt10-3 by the similar way as above untill a complete ORF was obtained. Finally, a 1,970 bp sequence (termed as dimethylglycine dehydrogenase like gene isoform I, DMGDHL1a) containing a 1,428 bp complete coding sequence from the live cDNA library and 1,475 bp sequence (isoform II, termed as DMGDHL1b) containing a 1,296 bp complete coding sequence from the fetas live cDNA library were obtained. Fourteen exons were identified in isoform I and the first nine exons of isoform II which shared with isoform I could be determined too. The last 105 bp cDNA sequence of isoform II could not be found in the public database, indicating a very large intron (> 123 kb) existed between exon 9 and exon 10 of isoform II. DMGDHL1 showed highly homology on both cDNA and amino acid level with rat dimethylglycine dehydrogenase (60% identity in 135 bp and 35% identity in 436 residues respectively). It was reported that human sarcosinemia gene was mapped at 9q34. Therefore it could be a good candidate gene for the sarcosinemia.

Aristolochic acid I-induced apoptosis in LLC-PK1 cells and amelioration of the apoptotic damage by calcium antagonist

OBJECTIVE

To examine the effect of different concentrations of aristolochic acid I (AAI) in inducing apoptosis of cultured porcine renal cell line LLC-PK1 and to investigate the relationship between intracellular free calcium concentration ([Ca++]i) and LLC-PK1 apoptosis induced by AAI and the influence of a calcium antagonist, lacidipine on apoptosis and [Ca++]i.

METHODS

LLC-PK1 cells were treated in different groups: a. the normal group without treatment; b. the group with AAl alone (0.01 g.L-1, 0.02 g.L-1, 0.04 g.L-1, 0.08 g.L-1); c. the group with lacidipine alone (10 ng.L-1, 10(2) ng.L-1, 10(3) ng.L-1); d. the group with AAI (0.04 g.L-1) plus lacidipine (10 ng.L-1, 10(2) ng.L-1, 10(3) ng.L-1). Light microscopy, agarose gel electrophoresis, Annexin-V-Flous apoptosis detection kit and flow cytometry using propidium iodide staining to identify or quantify the apoptosis of LLC-PK1 cells. Mean [Ca++]i was measured by laser confocus microscopy using Fluo-3/AM staining.

RESULTS

A series of morphologic changes that were characteristic of apoptosis, Annexin-V-Flous staining positive apoptotic cells and "DNA ladder" were identified in AAI (0.02 g.L-1-0.08 g.L-1) treated LLC-PK1 cells. Quantitative analysis of apoptotic cells showed that the percentage of apoptotic cells in AAI (0.02 g.L-1, 0.04 g.L-1 or 0.08 g.L-1) group was significantly higher than that in normal group (5.3%, 48.5%, 78.7% vs 2.6%, P < 0.001). Mean [Ca++]i was significantly higher in cells treated with AAI (0.04 g.L-1) than that in normal cells (58.01 +/- 18.89 vs 22.66 +/- 4.78, P < 0.001). In group treated with AAI plus lacidipine (102 ng.L-1, 103 ng.L-1), mean [Ca++]i was significantly lower than that treated with AAI alone (35.47 +/- 12.85, 28.55 +/- 10.16 vs 58.01 +/- 18.89, P < 0.001). And the percentage of apoptotic cells in group treated with AAI plus lacidipine (10(2) ng.L-1, 10(3) ng.L-1) was also significantly lower than that treated with AAI alone (19.0%, 27.8% vs 34.7%, P < 0.001).

CONCLUSIONS

High concentrations of AAI may induce apoptosis of LLC-PK1 cells. The mean [Ca++]i in AAI-treated LLC-PK1 cells was increased significantly, suggesting that the increase of [Ca++]i may be related to apoptosis in LLC-PK1 cells. Lacidipine may decrease the raised mean [Ca++]i levels caused by AAI and the percentage of apoptotic cells, and lacidipine may ameliorate AAI-induced apoptotic damage by inhibiting the increase of [Ca++]i in LLC-PK1 cells.

Desulfotomaculum genus- and subgenus-specific 16S rRNA hybridization probes for environmental studies

Based on comparative analysis of 16S rRNA sequences and the recently established phylogeny of the genus Desulfotomaculum, a set of phylogenetically nested hybridization probes was developed and characterized. A genus-specific probe targets all known Desulfotomaculum species (with the exception of Desulfotomaculum acetoxidans), and five specific probes target subclusters within the Desulfotomaculum genus. The dissociation temperature of each probe was determined experimentally. Probe specificities were verified through hybridizations with pure culture rRNA isolated from a wide variety of target and non-target organisms and through an evaluation of probe 'nesting' using samples obtained from four different environments. Fixation and hybridization conditions for fluorescence in situ hybridizations were also optimized. The probes were used in quantitative membrane hybridizations to determine the abundance of Desulfotomaculum species in thermophilic anaerobic digesters, in soil, in human faeces and in pig colon samples. Desulfotomaculum rRNA accounted for 0.3-2.1% of the total rRNA in the digesters, 2.6-6.6% in soil, 1.5-3.3% in human faeces and 2.5-6.2% in pig colon samples.

[The common C677T polymorphism in the methylenetetrahydrofolate reductase gene is associated with neural tube defects and preeclampsia]

OBJECTIVE

To assess whether methylenetetrahydrofolate reductase(MTHFR) gene C677T polymorphism is associated with neural tube defects and preeclampsia.

METHODS

Twenty- four mothers who had given birth to normal children, 27 mothers who had given birth to NTDs children, 120 normal women, and 57 women who had suffered from preeclampsia were genotyped for C677T polymorphism by using PCR/RFLP method.

RESULTS

(1) VV genotype frequency in the normal mothers group it was 0.13, while in the NTDs mothers group it was 0.33; mothers with VV genotype were at 3 times increased risk to have a NTDs child, compared with the normal mothers. (2) In the normal women group VV genotype frequency was 0.15, while in the preeclampsia women group it was 0.31; women with VV genotype were at 2.5 times increased risk to have preeclampsia, compared with the normal women.

CONCLUSION

The authors believe that MTHFR VV genotype is associated with the development of NTDs and preeclampsia.

Changes in muscle strength, muscle fibre size and myofibrillar gene expression after immobilization and retraining in humans

1. Changes in muscle strength, vastus lateralis fibre characteristics and myosin heavy-chain (MyoHC) gene expression were examined in 48 men and women following 3 weeks of knee immobilization and after 12 weeks of retraining with 1866 eccentric, concentric or mixed contractions. 2. Immobilization reduced eccentric, concentric and isometric strength by 47 %. After 2 weeks of spontaneous recovery there still was an average strength deficit of 11 %. With eccentric and mixed compared with concentric retraining the rate of strength recovery was faster and the eccentric and isometric strength gains greater. 3. Immobilization reduced type I, IIa and IIx muscle fibre areas by 13, 10 and 10 %, respectively and after 2 weeks of spontaneous recovery from immobilization these fibres were 5 % smaller than at baseline. Hypertrophy of type I, IIa and IIx fibres relative to baseline was 10, 16 and 16 % after eccentric and 11, 9 and 10 % after mixed training (all P < 0.05), exceeding the 4, 5 and 5 % gains after concentric training. Type IIa and IIx fibre enlargements were greatest after eccentric training. 4. Total RNA/wet muscle weight and ty I, IIa and IIx MyoHC mRNA levels did not change differently after immobilization and retraining. Immobilization downregulated the expression of type I MyoHC mRNA to 0.72-fold of baseline and exercise training upregulated it to 0.95 of baseline. No changes occurred in type IIa MyoHC mRNA. Immobilization and exercise training upregulated type IIx MyoHC mRNA 2.9-fold and 1.2-fold, respectively. For the immobilization segment, type I, IIa and IIx fibre area and type I, IIa and IIx MyoHC mRNA correlated (r = 0.66, r = 0.07 and r = -0.71, respectively). 5. The present data underscore the role muscle lengthening plays in human neuromuscular function and adaptation.

Quantification of Methanosaeta Species in Anaerobic Bioreactors Using Genus- and Species-Specific Hybridization Probes

A BSTRACTTo evaluate the role of Methanosaeta spp. in a variety of anaerobic environments, small-subunit rRNA targeted oligonucleotide hybridization probes were developed and experimentally characterized. The probes were designed to be genus specific for Methanosaeta and species specific for Methanosaeta concilii and Methanosaeta thermophila. The temperature of dissociation was determined for each probe. Probe specificities were determined using a diverse collection of Archaea and through an evaluation of probe nesting using samples from a variety of anaerobic bioreactors. Cell fixation and hybridization conditions for fluorescence in situ hybridizations were also evaluated. Although permeability of methanogens was variable, M. concilii cells could be permeabilized using a range of paraformaldehyde and ethanol based fixation conditions. Using the newly designed probes together with previously designed probes for methanogens, it was determined that Methanosaeta spp. were the dominant aceticlastic methanogens in a variety of anaerobic bioreactors when acetate concentrations were low. Their levels were higher in bioreactors with granular sludge than in those with flocculent sludge. In lab-scale upflow anaerobic sludge blanket reactors, the levels of M. concilii rRNA were as high as 30% of the total rRNA.

[Overexpression of Bcl-2 inhibited T lymphocyte apoptosis mediated by CD3 epsilon molecule]

OBJECTIVE

To study the role of bcl-2 gene overexpression in T lymphocyte apoptosis mediated by CD8 epsilon chimera molecule.

METHODS

The cells expressed CD8 epsilon chimera molecule were transfected with a bcl-2 expression vector. The cells with Bcl-2 overexperssion were selected by G418 and limited dilution, and then treated with anti-CD8 antibody. The cell death was evaluated with flow cytometry.

RESULTS

It was shown that there were only 2.6% of cells with Bcl-2 overexpression died by apoptosis. Comparing with Jurkat and TJK cells without Bcl-2 expression, in which there were 6.1% and 33.7% of cell death respectively, suggesting that Bcl-2 overexpression remarkbly inhibited apoptosis of the T lymphocytes mediated by CD8 epsilon chimera molecule.

CONCLUSIONS

Bcl-2 overexpression could block T lymphocyte apoptosis mediated by CD3 epsilon molecule and the mechanisms remained to be clarified in detail.

[Light and electron microscope observations of heart and vascular tissues in animals acutely infected with tubercle bacilli]

The objective of this study was to observe the heart and vascular pathological lesions of some animals acutely infected with H37Rv tubercle bacilli. C57 BL/6N mice and rabbits were used for the establishment of the models. Light sections were stained with HE, Z-N, MCT and BCGS-P. Ultrathin sections were stained with uranyl and lead citrate and examined by electron microscope. The results showed that tubercle bacilli were present in heart and vascular tissues. Myocardial fibre, pericardium and vascular tissues had various degrees of lesions. The lesions of myocardial fibre and pericardium were more serious than that of the vascular tissues. These findings suggest that the toxin of the tubercle bacilli can damage the tissues of the infected animals, and the excessive reproduction can be also a factor detrimental to the infected tissues.

The role of the renin-angiotensin and cardiac sympathetic nervous systems in the development of hypertension and left ventricular hypertrophy in spontaneously hypertensive rats

To elucidate the relationship between the development of left ventricular hypertrophy (LVH) in hypertension and the development of both the cardiac sympathetic nervous and renin-angiotensin systems, as measured by norepinephrine and angiotensin II levels, respectively. In this longitudinal study, we compared blood pressure (BP), left ventricular weight, and norepinephrine (NE) and angiotensin II (Ang II) concentrations, in Spontaneously Hypertensive Rats (SHR) and age-matched Wistar-Kyoto (WKY) rats at 5, 10, 15, 20, and 28 wk of age. Blood pressure, plasma and ventricular Ang II and tissue NE were measured by the tail-cuff method, radioimmunoassay, and high-performance liquid chromatography (HPLC), respectively. At 5 wk, systolic blood pressure was the same in both strains. But the left ventricular plus septum weight to body weight (LVSW/BW) ratio was higher in SHR than in WKY rats (p < 0.01), which finding may have been related to the increased cardiac tissue NE concentration, and this increase tended to parallel the rise in blood pressure. Both left ventricle and forelimb muscle NE concentrations were significantly higher in SHR than in WKY rats at 5, 10, and 15 wk of age (p < 0.01, respectively), and were similar at 20 and 28 wk of age. The heart and plasma Ang II levels decreased with age, which results were in keeping with the known developmental tendencies of the biological aging progress. There was no significant difference in plasma Ang II levels between the two strains from 5 to 20 wk, whereas these levels were remarkably higher in WKY than in SHR rats at 28 wk (p< 0.01). Otherwise, the left ventricular tissue Ang II concentrations were significantly higher in SHR than in WKY rats at the late stage (from 15 to 28 wk), which may have contributed to the late-stage cardiac hypertrophy. These results suggested that the sympathetic nervous system (SNS) and the renin-angiotensin-system (RAS) in SHR may contribute to the pathogenesis of hypertension and LVH at the early and late stages, respectively.

[The effect of chlamydia trachomatis infection in pregnant women on pregnant outcome and neonates]

OBJECTIVE

To determine the prevalence of chlamydia trachomatis (CT) in pregnant women and its effect on pregnant outcome and neonate.

METHODS

Specimen of cervical swab were collected and detected for CT by polymerase chain reaction (PCR) method meanwhile relevant factors were investigated. Pregnant outcome and neonatal situation were also followed up.

RESULTS

The infection rates of CT in pregnant women were 35.90%. The Incidence of abnormal pregnant outcome (premature delivery and abortion) was significantly higher in CT positive groups (24.72%) than that in negative groups (12.20%) (P < 0.05). Incidence of neonatal conjunctivitis and pneumonia were significantly higher in CT positive groups (17.98%) than that of negative groups (0.61%) (P < 0.01). There was statistically significant difference in the prevalence of low birth weight (< 2,500 g) between the two groups (13.48% versus 4.88%) (P < 0.05), and mode of delivery also had influence on neonatal morbidity.

CONCLUSION

Prevalence of CT infection in pregnant women is rather common, and it may cause adverse pregnancy outcome.

An A/G polymorphism in the promoter of mitochondrial aldehyde dehydrogenase (ALDH2): effects of the sequence variant on transcription factor binding and promoter strength

INTRODUCTION

The strong protective effect of the ALDH2*2 mutation on risk of alcoholism suggests that other mutations that reduce mitochondrial aldehyde dehydrogenase (ALDH) activity in the liver might also deter drinking. This study describes a polymorphic locus found in the promoter of the ALDH2 gene that affects expression of reporter constructs.

METHODS

Polymerase chain reaction (PCR)-based sequencing was used to search for polymorphisms. The ability of the promoter variants to bind transcription factors apolipoprotein A regulatory protein 1 (ARP-1) and chicken ovalbumin upstream promoter-transcription factor (COUP-TF) was tested in gel retardation assays using in vitro synthesized transcription factors. The variant promoters were tested for transcriptional activity using a heterologous promoter system and transient transfection assays.

RESULTS

A common polymorphism (A or G) in the human ALDH2 promoter region was found at -361 base pair (bp) from the translation start site. This polymorphism was found at different frequencies in African Americans, Caucasians, and Asians. The polymorphism occurs adjacent to the core binding motif for the transcription factors COUP-TF and ARP-1. Competition and binding affinity determinations did not show differences in the ability of these two sequences to bind the factors. Reporter genes containing these elements upstream of a basal thymidine kinase promoter had similar activity when transfected into a fibroblast (CV-1) cell line. However, the reporter containing the G allele was more active than that containing the A allele in hepatoma (H4IIEC3) cells.

CONCLUSIONS

The -361 bp A/G polymorphism is common in all racial groups tested. The G allele was more active than the A allele in a transfection assay. The basis for this difference is not known. If the differences in activity of the promoter constructs were paralleled by differences in ALDH2 enzyme activity in the liver, this polymorphism could affect risk of alcoholism.

Impact of hyperinsulinemia on myosin heavy chain gene regulation

The purpose of this study was to determine whether hyperinsulinemia alters myosin heavy chain (MHC) gene expression in human skeletal muscle. A biopsy from the vastus lateralis was obtained in young, lean [age 24.6 +/- 1.0 (SE) yr, body fat 11.9 +/- 1.9%, body mass index 26.1 +/- 1.1 kg/m2; n = 10] men before and after 3 h of hyperinsulinemia (hyperinsulinemic-euglycemic clamp). Muscle was analyzed for mRNA of type I, IIa, and IIx MHC isoforms. Hyperinsulinemia (mean of 1,065.7 +/- 9.8 pmol/l during minutes 20 to 180) did not change (P > 0.05) the mRNA concentration of either the type I MHC or type IIA MHC isoforms. In contrast, type IIX MHC mRNA increased (P < 0.05) with hyperinsulinemia compared with the fasted condition. These data indicate that hyperinsulinemia rapidly increases type IIx MHC mRNA in human skeletal muscle.

A PCR method for typing B-L beta II family (class II MHC) alleles in broiler chickens

Certain haplotypes of the major histocompatibility (B) complex are strongly associated with resistance or susceptibility to several infectious diseases in Leghorn chickens. Identification of chicken haplotypes based on the nucleotide sequence of B complex loci could provide more precise identification of haplotypes than traditional serological methods. We report the development and application of polymerase chain reaction with sequence specific primers (PCR-SSP) to type broiler chicken B haplotypes based on the DNA sequence of B-L beta II family genes. Five well-defined standard B haplotypes from White Leghorns and 12 recently characterized B haplotypes from a broiler breeder line were used to develop the test system. The B-L beta II family loci were amplified from genomic DNA by B-L beta II family specific primers and then characterized by PCR-SSP. In total, ten pairs of primers, derived from the sequences of expressed B-L beta II family alleles, were used in the PCR typing test to discriminate the chicken B haplotypes identified previously by serological means. The PCR-SSP showed that each haplotype had a different amplification pattern, except those haplotypes known or suspected to have the same B-L beta alleles. Cloning and sequencing of the family specific PCR products indicated that two loci in the B-L beta II family, presumably B-L beta I and B-L beta II, were amplified. Finally, B-L beta PCR-SSP typing was used in combination with B-G RFLP analyses to characterize unusual (variant) B serotypes; the results indicate that some of these are natural recombinants within the B complex.

Effect of endurance exercise on myosin heavy chain gene regulation in human skeletal muscle

The purpose of this study was to determine the effect of endurance-oriented exercise on myosin heavy chain (MHC) isoform regulation in human skeletal muscle. Exercise consisted of 1 h of cycle ergometer work per day at 75% maximal oxygen consumption for seven consecutive days. Muscle was obtained before the first bout of exercise, 3 h after the first bout of exercise, and before and 3 h after the final exercise bout on day 7 (n = 9 subjects). No changes in MHC mRNA (I, IIa, IIx) were evident after the first exercise period. There was, however, a significant (P < 0.05) decline (-30%) in MHC IIx mRNA 3 h after the final training bout. An interesting finding was that a higher pretraining level of MHC IIx mRNA was associated with a greater decline in the transcript before (r = 0.68, P < 0.05) and 3 h after (r = 0.82, P < 0.05) the final exercise bout. These findings suggest that MHC IIx mRNA is downregulated during the early phase of endurance-oriented exercise training in human skeletal muscle but only after repeated contractile activity. Pretraining MHC IIx mRNA content may influence the magnitude of this response.

All-trans retinoic acid reduces intimal thickening after balloon angioplasty in atherosclerotic rabbits

OBJECTIVE

To investigate the effects of oral administration of all-trans retinoic acid (ATRA) on inhibition of intimal thickening after balloon angioplasty in the rabbit iliac artery atherosclerotic model.

METHODS

Iliac atherosclerosis was induced in 24 rabbits, and balloon angioplasty was performed. At angioplasty, 24 rabbits were randomly divided into four groups (n = 6 per group): Group 1: controls not receiving oral ATRA administration; Group 2: receiving oral ATRA (0.6 mg.kg-1.d-1) administration beginning 1 week prior to angioplasty and continuing for 4 weeks; Group 3: receiving oral ATRA (0.6 mg.kg-1.d-1) administration beginning immediately after angioplasty and continuing for 4 wk; Group 4: receiving oral ATRA (0.6 mg.kg-1.d-1) administration beginning 1 wk after angioplasty and continuing for 4 wk. Values of cross-sectional area, ratio of intimal/medial area and thickness were determined by a computer-based morphometric system, and cell proliferative activity was assessed by 3H-thymidine incorporation.

RESULTS

Both the cross-sectional area and the ratio of intimal/medial area and thickness were significantly reduced by ATRA administration compared with control group (P < 0.01). The inhibitory effect is less potent when ATRA is administered 1 week before angioplasty. The ATRA inhibitory effect when administered 1 week after angioplasty is not different significantly form that when administered immediately after angioplasty. The 3H-thymidine incorporation was also decreased in ATRA-treated rabbits compared with controls (P < 0.01).

CONCLUSIONS

Oral ATRA administration can be effective in inhibiting intimal thickening after balloon angioplasty. It is reasonable that ATRA should be administered immediately after angioplasty.

Regulation of skeletal muscle UCP-2 and UCP-3 gene expression by exercise and denervation

The factors that regulate gene expression of uncoupling proteins 2 and 3 (UCP-2 and UCP-3) in skeletal muscle are poorly understood, but both genes are clearly responsive to the metabolic state of the organism. Therefore, we tested the hypothesis that denervation and acute and/or chronic exercise (factors that profoundly affect metabolism) would alter UCP-2 and UCP-3 gene expression. For the denervation studies, the sciatic nerve of rat and mouse hindlimb was sectioned in one leg while the contralateral limb served as control. Northern blot analysis revealed that denervation was associated with a 331% increase (P < 0.001) in UCP-3 mRNA and a 200% increase (P < 0. 01) in UCP-2 mRNA levels in rat mixed gastrocnemius (MG) muscle. In contrast, denervation caused a 53% decrease (P < 0.001) in UCP-3 and a 63% increase (P < 0.01) in UCP-2 mRNA levels in mouse MG. After acute exercise (2-h treadmill running), rat UCP-3 mRNA levels were elevated (vs. sedentary control) 252% (P < 0.0001) in white gastrocnemius and 63% (P < 0.05) in red gastrocnemius muscles, whereas UCP-2 levels were unaffected. To a lesser extent, elevations in UCP-3 mRNA (22%; P < 0.01) and UCP-2 mRNA (55%; P < 0.01) levels were observed after acute exercise in the mouse MG. There were no changes in either UCP-2 or UCP-3 mRNA levels after chronic exercise (9 wk of wheel running). These results indicate that acute exercise and denervation regulate gene expression of skeletal muscle UCPs.

Mutations in the gene encoding gap junction protein beta-3 associated with autosomal dominant hearing impairment

Hearing impairment is the most commonly occurring condition that affects the ability of humans to communicate. More than 50% of the cases of profound early-onset deafness are caused by genetic factors. Over 40 loci for non-syndromic deafness have been genetically mapped, and mutations in several genes have been shown to cause hearing loss. Mutations in the gene encoding connexin 26 (GJB2) cause both autosomal recessive and dominant forms of hearing impairment. To study the possible involvement of other members of the connexin family in hereditary hearing impairment, we cloned the gene (GJB3) encoding human gap junction protein beta-3 using homologous EST searching and nested PCR. GJB3 was mapped to human chromosome 1p33-p35. Mutation analysis revealed that a missense mutation and a nonsense mutation of GJB3 were associated with high-frequency hearing loss in two families. Moreover, expression of Gjb3 was identified in rat inner ear tissue by RT-PCR. These findings suggest that mutations in GJB3 may be responsible for bilateral high-frequency hearing impairment.

Overview of the Diabetes Initiative of South Carolina

Implementation is underway for many of these programs, and there are descriptions of activities elsewhere in this symposium. The Board recognizes that in dealing with the complications of a chronic disease like diabetes, many years of intense effort will be needed before significant results may be appreciated. Progress will be monitored regularly by the Surveillance Council and SCDCP/DHEC, and modifications of the plan will be made by the Board at intervals after review of the data. We are optimistic that over the next decade, this system will make a significant impact to reduce mortality, morbidity, and costs of diabetes, and the result will be an increased quality of life for people affected by diabetes in South Carolina.

Diabetes patient education

Not all medical practices are equipped to provide diabetes self-management training. Physicians can incorporate a team approach in their practice by establishing collaborative relationships with recognized diabetes education programs. The ADA's education recognition program has identified diabetes education programs that meet the National Standards for Diabetes Self-Management Education Programs. This list is available on the ADA's web site at http://www.diabetes.org/recognition and is printed twice a year in Diabetes Forecast. The National Certification Board for Diabetes Educators (NDEA) can provide a list of CDEs in your area. The South Carolina Model Diabetes Patient Education Program of DSC and SCDCP/DHEC is an excellent critical step towards obtaining ADA recognition.

Tachycardia alone fails to change the myocardial pharmacokinetics and dynamics of lidocaine, thiopental, and verapamil after intravenous bolus administration in sheep

Previous reports have suggested that tachycardia alone can increase the rate of myocardial uptake of some drugs. As part of a systematic study of the determinants of the myocardial uptake and effects of drugs in critical illness, the effect of tachycardia induced by intracardiac pacing on the myocardial disposition and effects of lidocaine, verapamil, and thiopental were studied in chronically instrumented sheep. For each drug, seven sheep received either 100 mg of lidocaine, 10 mg of verapamil, or 750 mg of thiopental over 2 min in unpaced and paced (140 beats/min) states on separate occasions and in random order. Arterial and coronary sinus (effluent from the heart) blood samples were taken at regular intervals for 30 min, and the maximum rate of change of left ventricular pressure (LV dP/dtmax) was measured as an index of myocardial contractility. There were no differences between unpaced and paced studies in the time courses of arterial and coronary sinus concentrations, or the time-courses of myocardial contractility and blood flow, after bolus iv injections of these drugs. Tachycardia alone does not appear to influence the myocardial kinetics or dynamics of lipophilic drugs that can rapidly diffuse into the heart.

16-microm infrared generation by difference-frequency mixing in diffusion-bonded-stacked GaAs

Tunable 90-ps 15.6-17.6-microm coherent radiation was generated by means of difference-frequency mixing in diffusion-bonded-stacked GaAs. The sample consisted of 24 alternately rotated layers with a total length of 6 mm and with low optical loss to achieve third-order quasi-phase matching. The wavelength-tuning curve was close to the theoretical prediction, demonstrating that the bonding process maintained nonlinear optical phase matching over the entire interaction length. Maximum conversion efficiency of 0.7%, or 5% internal quantum efficiency, was measured at 16.6 microm, consistent with the theoretical predictions.

[Observation of complications at the operative and early postoperative stages of phacoemulsification]

PURPOSE

The study was designed to investigate the reason and management of the complications at the initial stage of studying the technique of phacoemulsification.

METHODS

Observing the complications at the operative and early postoperative stages of phacoemulsification used in situ nuclear fracture technique or in iridial plain fracture technique on 233 eyes of 212 patients with cataract.

RESULTS

During the operations the rate of vitreous loss was 8.6% (20 eyes); iridial damage was 5.6% (13 eyes); hemorrhage in the anterior chamber was 0.4% (1 eye). After the operations the rate of continued corneal edema was 1.3% (3 eyes); posterior capsular opacity was 3.0% (7 eyes); inflammation was 0.9% (2 eyes); discentral location of intraocular lens was 0.4% (1 eye); leakage of wound was 0.9% (2 eyes); hemorrhage in the anterior chamber was 0.4% (1 eye).

CONCLUSION

Vitreous loss and iridial damage were the frequent complications at the initial stage of studying the technique of phacoemusification. The rate of the complications was lower in situ nuclear fracture technique than in iridial plain fracture technique.

The influence of the bolus injection rate of propofol on its cardiovascular effects and peak blood concentrations in sheep

The influence of the bolus injection rate of propofol on its cardiovascular effects has not been extensively studied. We therefore examined the influence of the injection rate of i.v. bolus doses of propofol on its acute cardiovascular effects and peak blood concentrations in seven chronically instrumented sheep. Each received i.v. propofol (200 mg) over 2 min (slow injection) and 0.5 min (rapid injection) on separate occasions in random order. The rapid injection was associated with more profound decreases in mean arterial blood pressure than slow injection (35.7% vs 23.7% maximal reductions from baseline, respectively; P = 0.02). There were no significant differences between the injection rates for peak reductions in myocardial contractility, increases in heart rate, or degree of respiratory depression. Concurrently, the rapid injections were associated with significantly higher arterial (26.9 vs 11.9 mg/L) propofol concentrations in a manner consistent with indicator dilution principles. There were no differences in the peak coronary sinus concentrations between the injection rates. We conclude that the rapid injection of propofol in the context of the induction of anesthesia produced significantly higher peak arterial propofol concentrations and suggest that it is these higher concentrations that produced relatively greater reductions in arterial blood pressure from rapid injections.

IMPLICATIONS

Propofol is injected into a vein to initiate anesthesia. It can cause a rapid decrease in blood pressure, which may be dangerous to the patient. We examined the effect of rapid and slow injection rates of propofol in sheep and found that rapid injection caused a greater decrease in blood pressure. This was because rapid injection caused higher concentrations of propofol in the blood immediately after the injection. We believe that if the same processes occur in humans, there may be little advantage in injecting propofol rapidly.

[Histologic study on the pulpal response after complete crown preparation]

Protecting pulp health during preparation procedures is one of the key factors for prosthesis success. The histological sections of dental pulp showed the disruption of odontoblastic layer, blood vessels hyperemia and local bleeding. Dental histological sections of 40 healthy teeth which would need to be detracted because of orthodontical treatment were made to observe the pulp response in vivo during different tooth preparation time, including four groups: before preparation, after preparation, one week after being covered with temporary crown and two weeks after being covered with temporary crown. when air-water spray was used during crown preparation, Healing of the pulp was apparent 2 weeks following preparation, when the prepared teeth were covered with temporary crown and cemented with zinc oxide eugenol.

[8-chloro-adenosine induced apoptosis in various human tumor cell lines]

OBJECTIVE

To study the effect of 8-Chloro-adenosine (8CA) on tumor cell growth and apoptosis.

METHODS

Tumor and normal cell lines were treated with 8CA at different concentrations and cell growth was analysed by MTT assay. Cell apoptosis was evaluated by light microscopy, flow cytometry and chromosome DNA fragmentation.

RESULTS

Treatment with 8CA at 10 mumol/L remarkably inhibited tumor cell growth. HL-60 promyelocytic leukemia cell line was more sensitive to 8CA than MGc-803 gastric mucoid adenocarcinoma cell line. NIH3T3 cells were relatively resistant to 8CA. The IC50 of HL-60 and MGc-803 cells was 1.2 mumol/L and 1.8 mumol/L, respectively, while that of NIH3T3 cells was 12 mumol/L. Further study showed that 8CA induced HL-60 and MGc-803 cell death characterized by apoptotic phenotypes, DNA content changes and chromosome DNA fragmentation.

CONCLUSION

8CA is a potential agent for tumor chemotherapy.

The enantiomer-specific kinetics and dynamics of verapamil after rapid intravenous administration to sheep: physiological analysis and modeling

The lung, myocardial and systemic kinetics of the enantiomers of verapamil, and their myocardial effects, were measured after administration of 10 mg of racemic verapamil during 2 min to chronically instrumented sheep; the data were used to develop a physiological model of the process. Verapamil was characterized by relatively slow transit through the lungs and heart. The lung kinetic values were membrane limited, whereas the tissue/blood equilibrium half-life for the heart was approximately 8 min. There was little difference between the kinetic values of the enantiomers, with the exception of their extent of deep distribution into the lung. The time course of the increase in myocardial blood flow caused by verapamil was best related to the time course of the arterial verapamil concentrations, whereas the time course of increases in the interval between P and R waves of the electrocardiogram and decreases in the maximum rate of rise of left ventricular pressure were best related to the time course of its myocardial concentrations. Thus, the observed hysteresis for these effects compared with arterial blood was largely caused by the time required for the myocardial equilibration. The model predicted that the myocardial concentrations of verapamil were relatively insensitive to the duration of injection of a given bolus dose, but that rapid injection caused transient, high arterial concentrations. It also predicted that the bolus dose of verapamil should be modified over a 2-fold range to account for physiologically plausible variations in base-line cardiac output and myocardial blood flow.

[Rheumatoid arthritis synoviocyte hyperplasia and expression of fas and bcl-2 genes]

OBJECTIVE

To determine whether apoptosis occurs in the proliferative synovial tissue and cells from patients with rheumatoid arthritis (RA).

METHODS

In situ hybridization was carried out by using labeled RNA probes of fas, fasL, and bcl-2 synthesized by in vitro transcription. Apoptosis was examined by DNA electrophoresis and flow cytometry.

RESULTS

fas mRNAs were expressed in 6 of 7 patients with RA. bcl-2 mRNAs were positive in 5 of 7 patients with RA. fasL mRNAs were not detectable in all the patients. bcl-2 mRNAs were always coexpressed with fas in RA synovial lining cells. The positive rates of fas and bcl-2 expression in RA synovial tissues were significantly higher than those of patients with osteoarthritis (OA) and normal synovial tissues (P < 0.05). Immunochemistry staining showed that Fas and Bcl-2 proteins were expressed in the synovial lining cells. Nucleic DNA extracted from the synovial tissues of 6 patients with RA, 4 patients with OA and 2 normal controls. Agarose gel electrophoresis demonstrated that DNA ladders occurred in only one OA synovial tissue. The spontaneous apoptosis in cultured synoviocytes from patients with RA and OA was lower as analyzed by immunofluorescence staining and flow cytometry.

CONCLUSION

The phenomena of apoptosis in RA synoviocytes was not significant and overexpression of bcl-2 perhaps inhibited apoptosis in these cells, leading to hyperplasia of RA synoviocytes.

Kindling and associated mossy fibre sprouting are not affected in mice deficient of NGFI-A/NGFI-B genes

Kindling is an animal model of epileptogenesis, whereby repeated administration of an initially subconvulsive electrical stimulation eventually leads to the development of generalized motor seizures. Once established, the kindling effect is permanent. Although the molecular basis of kindling remains incompletely understood, emerging lines of evidence suggest that the induction of immediate-early genes could represent a link between periodic short-term stimuli and the long-lasting functional and structural alterations in the brain associated with the development of seizures. A recent study showed that null mutation of the immediate-early gene c-fos impairs the structural and functional plasticities in kindling. In the present study, we examined whether two other seizure-inducible immediate-early genes--NGFI-A (also termed EGR-1, zifl268, and Krox-24) and NGFI-B (also termed Nur77)--play requisite roles in kindling. We found that neither the rate of kindling nor seizure-induced granule cell axonal sprouting was affected in mice carrying a null mutation of NGFI-A. Furthermore, double knock-out of NGFI-A and NGFI-B genes does not result in detectable changes in kindling development and associated mossy fibre sprouting. Taken together, our observations indicate that neither constitutive nor seizure-induced expression of NGFI-A or NGFI-B is uniquely required for the establishment of kindling. These findings underscore the specificity of the immediate-early genes whose transcriptional activation contributes to kindling epileptogenesis.

gp120-directed antibody-dependent cellular cytotoxicity as a major determinant of the rate of decline in CD4 percentage in HIV-1 disease

OBJECTIVE

To determine the relationship between the rate of CD4 percentage decline and two factors postulated to be associated with CD4 cell destruction: circulating HIV-1 viral load and gp120-directed antibody-dependent cellular cytotoxicity (ADCC).

DESIGN

Four women and 16 men had serial determinations of CD4 percentage gp120-directed ADCC activity [using the cell-mediated cytotoxicity (CMC) assay] natural killer (NK) cell number, spontaneous NK lytic function, and plasma HIV-1 RNA.

METHODS

The rate of decline in CD4 percentage was modeled as a function of gp120-directed ADCC activity and circulating HIV-1 RNA using Pearson correlation and multiple regression analyses.

RESULTS

All individuals had at least four CMC assays performed and two HIV-1 RNA polymerase chain reaction measurements over a median follow-up of 27 months. Although the rate of CD4 percentage decline was associated with either CMC activity (r = -0.53, P = 0.02) or circulating HIV-1 RNA (r = -0.42, P = 0.07), it was strongly correlated with an interaction between CMC and HIV-1 RNA (r = -0.76, P < 0.0001). Mean CMC activity was associated with both mean percentage of circulating NK cells and mean spontaneous NK cell lysis.

CONCLUSIONS

The ability of cells from HIV-infected individuals to mediate gp120-directed ADCC, together with a sufficient circulating viral load, define conditions under which rapid CD4 cell destruction may occur. This relationship between viral load and an HIV-1-specific immune response lends important insights into the central causes of immunodeficiency in AIDS and suggests additional avenues for therapeutic intervention.

The effects of short intravenous infusions of thiopentone on myocardial function, blood flow and oxygen consumption in sheep

The cardiovascular effects of slow (over two minutes) intravenous infusions of thiopentone 750 mg in conscious instrumented sheep breathing 100% oxygen were examined for 30 minutes following the start of the infusion. The maximum rate of rise of left ventricular pressure (an index of myocardial contractility) decreased significantly from 1 to 10 minutes, to a minimum of 45% of baseline. Heart rate increased by up to 33% above baseline from 0.5 min onwards. Both mean arterial pressure and cardiac output were decreased from between 1 and 7 min. Left ventricular minute work was transiently decreased, but left coronary blood flow and myocardial oxygen consumption showed little or no change from baseline. We conclude that in vivo, thiopentone administered at a relatively slow rate caused large reductions in myocardial contractility, and therefore cardiac reserve, in the absence of significant changes in myocardial blood flow or oxygen consumption.

Characterization of the mitochondrial cytochrome b gene from Venturia inaequalis

A new class of agricultural fungicides derived from the group of antifungal strobilurins acts as specific respiration inhibitors by binding to mitochondrial cytochrome b. The cytochrome b gene was cloned and sequenced from the mitochondrial genome of Venturia inaequalis, the causal agent of apple scab. The gene was 10.65 kbp in size and contained seven exons and six introns. The exons encoded a protein of 393 amino acids. Comparison of the deduced amino-acid sequence with cytochrome b proteins from other fungi revealed highest homologies to the respective proteins of Aspergillus nidulans, Podospora anserina and Neurospora crassa. All amino acids of the V. inaequalis cytochrome b at positions altered in mutants of Saccharomyces cerevisiae resistant to strobilurins, and other fungi with reduced sensitivities to strobilurins, were identical to wild-type isolates of several fungi. The cloning and characterization of the V. inaequalis cytochrome b gene is the initial step in the assessment of resistance risks inherent to the strobilurin fungicides.

Tyrosine phosphorylation of the CD3-epsilon subunit of the T cell antigen receptor mediates enhanced association with phosphatidylinositol 3-kinase in Jurkat T cells

T cell receptor signaling results both in T cell proliferation and apoptosis. A key enzyme at the intersection of these downstream pathways is phosphatidylinositol 3'-kinase (PI 3-kinase). In a previous report, we showed that the p85alpha subunit of the PI 3-kinase preferentially associated with the CD3-zeta membrane-proximal immunoreceptor tyrosine-based activation motif of the zeta chain (zetaA-ITAM) (Exley, M., Varticovski, L., Peter, M., Sancho, J., and Terhorst, C. (1994) J. Biol. Chem. 269, 15140-15146). Here, we demonstrate that tyrosine phosphorylation of CD3-epsilon can recruit the PI 3-kinase enzyme in a T cell activation-dependent manner. In vivo studies with Jurkat cells stably transfected with a CD8-CD3-epsilon chimera (termed CD8-epsilon) shows that ligation of endogenous CD3-epsilon or CD8-epsilon by specific antibodies induces tyrosine phosphorylation of CD3-epsilon or CD8-epsilon, respectively. Increased tyrosine phosphorylation correlates with increased binding of p85alpha PI 3-kinase and recruitment of PI 3-kinase enzymatic activity to CD3-epsilon or CD8-epsilon proteins. Mutagenesis studies in COS-7 cells, transiently transfected with CD8-epsilon, p85alpha, and Fyn cDNAs in various combinations, show that both Tyr170 and Tyr181 within the CD3-epsilon-ITAM are required for efficient binding of p85alpha PI 3-kinase. Thus, replacement of Tyr170 by Phe (Y170F), or Tyr181 by Phe (Y181F) significantly reduces binding of p85alpha PI 3-kinase, whereas it does not affect binding of Fyn. Further in vitro experiments suggest that a direct binding of the tandem SH2 domains of p85alpha PI 3-kinase to the two phosphorylated tyrosines in a single CD3-epsilon-ITAM may occur. The data also support a model in which a single CD3 subunit can recruit distinct effector molecules by means of TCR-mediated differential ITAM phosphorylation.

A 7.5-kbp region of the maize (T cytoplasm) mitochondrial genome contains a chloroplast-like trnI (CAT) pseudo gene and many short segments homologous to chloroplast and other known genes

The DNA sequence of a 7.5-kbp region from the maize cmsT mt genome was determined. Nucleotide-sequence analysis of this region reveals the presence of a ct-like trnI (CAT) gene, orf31 and orf48 which are respectively homologous to the trnI (CAT) gene in the maize and rice chloroplast genomes, and to orf28 and orf64 in the rice chloroplast genome. Northern-blot analysis indicates that the ct-like trnI (CAT) gene is likely to be a pseudo gene in the maize cmsT mt genome because it is not transcribed. A nucleotide-sequence homology search of this 7.5-kbp region reveals several short segments homologous to portions of chloroplast (ct), mitochondrial (mt) and other known genes. These segments range from 17 bp to 187 bp in length with homology from 71 to 100%. These observations also suggest that the transfer of DNA fragments from the ct genome to the mt genome may have occurred at different times during the evolution of the maize mt genome, and that multiple recombination events and rearrangements in both mt and ct genomes have occurred after the transfer of DNA fragments from the ct to the mt genome. A few segments were identified by their homology to be portions of genes from sources other than the ct genome. While it is known that large fragments of ctDNA have been transferred to maize mt genomes, this is the first report of the presence of numerous short ctDNA, or other foreign DNA segments, in the maize cmsT mt genome. These segments may provide valuable information regarding the evolution of plant mt genomes.