A catalogue of molecular, physiological and symbiotic properties of soybean-nodulating rhizobial strains from different soybean cropping areas of China

We have analysed 198 fast-growing soybean-nodulating rhizobial strains from four different regions of China for the following characteristics: generation time; number of plasmids; lipopolysaccharide (LPS), nodulation factors (LCOs) and PCR profiles; acidification of growth medium; capacity to grow at acid, neutral, and alkaline pH; growth on LC medium; growth at 28 and 37 degrees C; melanin production capacity; Congo red absorption and symbiotic characteristics. These unbiased analyses of a total subset of strains isolated from specific soybean-cropping areas (an approach which could be called "strainomics") can be used to answer various biological questions. We illustrate this by a comparison of the molecular characteristics of five strains with interesting symbiotic properties. From this comparison we conclude, for instance, that differences in the efficiency of nitrogen fixation or competitiveness for nodulation of these strains are not apparently related to differences in Nod factor structure.

Functional alpha1-adrenergic receptor subtypes in human right gastroepiploic artery

AIM

To study the functional alpha1-adrenergic receptor (alpha1-AR) subtypes in human right gastroepiploic artery (RGA).

METHODS

The effects of alpha2-AR, alpha1-AR, and alpha1-AR subtype selective antagonists on norepinephrine (NE)-induced vasoconstriction in isolated human RGA were observed by contractile function experiment.

RESULTS

Cumulative concentration-response curves for NE were competitively antagonized in RGA by alpha2-AR selective antagonist yohimbine (pA2 6.82+/-0.28, slope 1.12+/-0.40),alpha1-AR selective antagonist prazosin (pA2 9.77+/-0.22, slope 0.90+/-0.22),alpha1A-AR selective antagonists RS17053 (pA2 8.42+/-0.20, slope 0.93+/-0.20) and 5-MU (pA2 8.42+/-0.22, slope 0.88+/-0.18),alpha1D-AR selective antagonist BMY7378 (pA2 6.84+/-0.32, slope 1.05+/-0.17), and alpha1A-,alpha1B-AR selective antagonist WB4101 (pA2 8.88+/-0.20, slope 1.15+/-0.16). The correlation coefficients between these pA2 values of alpha1-AR selective antagonists with pKi values of which obtained from alpha1A-, alpha1B- and alpha1D-AR cloned cells are 0.95, 0.82, and 0.42. After the vessels were pretreated by chlorethylclonidine (CEC), an alpha1B- and alpha1D-AR irreversible alkylating agent, the pD2 values were changed from 5.9+/-0.5 to 5.6+/-0.6 and the maximal contraction was changed from (8.9+/-3.2) g to (8.0+/-3.2) g, respectively. The difference was not significant.

CONCLUSION

In human RGA, the contraction response is mainly mediated by alpha1-AR, of which alpha1A-AR plays an important role, whereas alpha1B- and alpha1D-AR are not involved in the contraction response.

Severe community-acquired pneumonia due to Acinetobacter baumannii

STUDY OBJECTIVES

To investigate the clinical, epidemiologic, and microbiological characteristics of community-acquired pneumonia (CAP) due to Acinetobacter baumannii.

METHODS

Retrospective chart and radiographic reviews of all patients who were admitted to National Taiwan University Hospital from January 1993 to August 1999, fulfilled the criteria for CAP, and had an isolate of A. baumannii from blood or pleural fluid at hospital admission.

RESULTS

Thirteen patients (9 men and 4 women; age range, 37 to 85 years) met the criteria. Conditions associated with the infection included male gender, old age, alcoholism, malignancy, cerebrovascular disease, diabetes mellitus, renal disease, and liver cirrhosis. Eleven patients (85%) acquired the infection during the warmer months of April to October. Twelve patients (92%) had a fulminant course presenting with septic shock and respiratory failure, and 11 patients (85%) needed ventilator support and were treated in an ICU. Six patients (46%) had leukopenia. Lobar consolidations were found in 12 patients (92%), and pleural effusions were present in 4 patients (31%). All patients had positive blood culture results, two patients (15%) had positive pleural effusion culture findings, and nine patients (69%) positive sputum culture results. All the isolates were susceptible to imipenem, and most were susceptible to aminoglycosides, ceftazidime, ciprofloxacin, and extended-spectrum penicillins. Eight patients (62%) died. Four of the five survivors were initially treated with combination of a third-generation cephalosporin and an aminoglycoside.

CONCLUSION

A. baumannii should be considered as a possible etiologic agent in community-acquired lobar pneumonia when (1) patients with a fulminant course present during the warmer and more humid months of the year, and (2) patients are younger alcoholics. A good sputum smear, defined as a Gram stain smear of an adequate sputum specimen that comes from the lower respiratory tract and contains > 25 leukocytes per high-power (100x) field on microscopic examination, can help early diagnosis and treatment. A combination of a third-generation cephalosporin and an aminoglycoside may be appropriate empirical therapy.

Antinociceptive effect of astragalosides and its mechanism of action

AIM

To study the effect and mechanism of astragalosides (AST) related to the antinociceptive activity.

METHODS

The standardized formalin test was performed to induce the direct stimulation of nociceptors followed by inflammatory process in the Kunming strain mice. The involvement of opioid and nitric oxide was studied by subcutaneous injection of morphine with/without naloxone 30 min before formalin test, or peritoneal injection of L-arginine with/without L-NAME 20 min before formalin.

RESULTS

AST 20, 40, and 80 mg/kg significantly lowered pain score of the second phase of formalin response as compared with control group (P<0.01). The maximum analgesic effect of AST 40 mg/kg was found at 4 h after the administration of AST (34.4 % inhibition at the second phase). Injection of morphine 5 mg/kg significantly inhibited pain response of both phases (P<0.01) and this was reversed by naloxone 2 mg/kg (P<0.01). However, naloxone did not alter the effect of AST on the second phase. Antinociceptive effect of AST 40 mg/kg was partially blocked by L-arginine 400 or 800 mg/kg (P<0.01).

CONCLUSION

AST has an antinociceptive effect on formalin test in mice that is not mediated by the endogenous opioid system but related to its inhibitory effect on the production of NO.

A model to study antioxidant regulation of endotoxemia-modulated neonatal granulopoiesis and granulocyte apoptosis

Neonates with septicemia tend to develop granulocytopenia, which may, in part, be due to septic mediators such as oxygen free radicals and tumor necrosis factor alpha (TNF-alpha). Granulocytopenia may be caused by a decrease in granulocyte growth and/or an increase in granulocyte destruction. In the present study, we investigated antioxidant regulation of endotoxin-modulated neonatal granulopoiesis and granulocyte apoptosis. Using human umbilical cord blood (HUCB), we found that simulating endotoxemia in vitro elicited significant superoxide production within a few minutes. Endotoxin exposure suppressed colony-forming unit-granulocyte and monocyte formation in a dose-dependent fashion. Addition of antioxidants such as N-acetyl-cysteine could reverse the endotoxin suppression of colony-forming unit-granulocyte and monocyte formation (13 +/- 5 versus 75 +/- 5 colony-forming units/mL). Spontaneous in vitro granulocyte apoptosis in 6 h, as reflected by phosphatidylserine expression on the cell surface, was higher in granulocytes from HUCB than in those from adult blood (10.8 +/- 1.0% versus 5.6 +/- 1.2%). The addition of endotoxin or IL-8 to the cells in the in vitro model did not promote granulocyte apoptosis, but TNF-alpha, a major mediator of the effects of endotoxin, significantly induced granulocyte apoptosis in HUCB (control versus TNF-alpha: 8.9 +/- 1.2% versus 35.9 +/- 2.9%). Addition of the antioxidant N-acetyl-cysteine effectively blocked TNF-alpha-induced granulocyte apoptosis as demonstrated by DNA fragmentation. Results from these studies indicate that oxygen radicals are directly involved in endotoxin suppression of granulopoiesis, and indirectly promote granulocyte apoptosis, presumably through TNF-alpha-mediated action. Thus, under certain conditions, modulation of oxygen radical production in the blood may benefit neonates with granulocytopenia.

US-guided transthoracic cutting biopsy for peripheral thoracic lesions less than 3 cm in diameter

PURPOSE

To evaluate the safety and accuracy of ultrasonography (US)-guided transthoracic cutting biopsy for diagnosing peripheral thoracic lesions (<3 cm).

MATERIALS AND METHODS

Fifty consecutive patients with peripheral thoracic lesions less than 3 cm in diameter underwent US-guided percutaneous transthoracic cutting biopsy with a modified technique. Fifty lesions (43 parenchymal lung, two pleural, two chest wall, and three anterior mediastinal lesions) were sampled for biopsy. The final diagnosis was based on histopathologic analysis of surgical specimens (n = 18) or clinical follow-up (n = 32).

RESULTS

The histology recovery rate was 98% (49 lesions), and the correct diagnosis was obtained in 48 lesions (96%). Twenty-four (48%) lesions were malignant, and 26 (52%) were benign. The diagnostic accuracy for malignant lesions was 92% (22 of 24 lesions). A specific benign diagnosis was made in 17 (65%) of the 26 benign lesions, and the negative predictive value for malignancy was 93% (26 of 28 lesions). Only two patients (4%) developed postbiopsy pneumothorax, and three (6%) developed postbiopsy hemoptysis. Biopsy helped prevent surgery or thoracoscopy in 32 patients (64%): 18 patients with benign disease and 14 with multiple metastases or inoperable cancer.

CONCLUSION

US-guided transthoracic cutting biopsy appears to be a safe and effective method for diagnosing peripheral thoracic lesions less than 3 cm in diameter. The high diagnostic accuracy for benign lesions and metastatic lung cancer can help prevent surgery in many cases.

Male circumcision and HIV acquisition and transmission: cohort studies in Rakai, Uganda. Rakai Project Team

BACKGROUND

Male circumcision is associated with reduced HIV acquisition.

METHODS

HIV acquisition was determined in a cohort of 5507 HIV-negative Ugandan men, and in 187 HIV-negative men in discordant relationships. Transmission was determined in 223 HIV-positive men with HIV-negative partners. HIV incidence per 100 person years (py) and adjusted rate ratios (RR) and 95% confidence intervals (CI) were estimated by Poisson regression. HIV-1 serum viral load was determined for the seropositive partners in HIV-discordant couples.

RESULTS

The prevalence of circumcision was 16.5% for all men; 99.1% in Muslims and 3.7% in non-Muslims. Circumcision was significantly associated with reduced HIV acquisition in the cohort as a whole (RR 0.53, CI 0.33-0.87), but not among non-Muslim men. Prepubertal circumcision significantly reduced HIV acquisition (RR 0.49, CI 0.26-0.82), but postpubertal circumcision did not. In discordant couples with HIV-negative men, no serconversions occurred in 50 circumcised men, whereas HIV acquisition was 16.7 per 100 py in uncircumcised men (P = 0.004). In couples with HIV-positive men, HIV transmission was significantly reduced in circumcised men with HIV viral loads less than 50000 copies/ml (P = 0.02).

INTERPRETATION

Prepubertal circumcision may reduce male HIV acquisition in a general population, but the protective effects are confounded by cultural and behavioral factors in Muslims. In discordant couples, circumcision reduces HIV acquisition and transmission. The assessment of circumcision for HIV prevention is complex and requires randomized trials.

Effects of indomethacin on secretory function of synoviocytes from adjuvant arthritis rats

In this study the effects of indomethacin on secondary inflammatory reaction and secretory function of synoviocytes were analyzed. The results show that secondary inflammatory reaction in adjuvant arthritis rats on days 16, 20 and 22 was suppressed significantly by intragastric administration of indomethacin in a dose of 2 mg/kg-1/d-1 for 10 days. Synoviocytes from adjuvant arthritis rats released a higher level of interleukin (IL)-1 and tumor necrosis factor (TNF) than that from the normal, control group. The synoviocyte culture supernatants of adjuvant arthritis rats were able to enhance the proliferation of synovial fibroblasts from normal rats in vitro. The synovial fibroblast proliferation mediated by the synoviocyte culture supernatants of adjuvant arthritis rats treated with indomethacin was promoted further because of the inhibition of prostaglandin (PG)E2 synthesis and the enhancement of IL-1 and TNF production in the synoviocytes from these animals. These results suggest that indomethacin is an effective antiinflammatory agent, but it is disadvantageous to the repair of joint destruction.

Effects of indomethacin on joint damage in rat and rabbit

AIM

To study the effects of indometacin (Ind) on joint damages.

METHODS

The volume of noninjected hind paw and interleukin-1 (IL-1) production from peritoneal macrophages and articular synoviocytes induced by lipopolysaccharides were assayed in adjuvant arthritis (AA) rats. Measurements of synovial fibroblast proliferative response and proteoglycan synthesis of cartilage from rabbits were used.

RESULTS

The secondary inflammatory reactions in AA rats on d 18, 21, and 24 were suppressed by i.g. Ind 2 mg.kg-1.d-1 for 9 d. Ind promoted IL-1 production from both macrophages and synoviocytes in AA rats. Ind 10 mumol.L-1 enhanced the proliferation of rabbit synovial fibroblasts and suppressed the proteoglycan synthesis of articular cartilage in response to IL-1 in vitro.

CONCLUSION

Ind is unfavorable to the repair of joint destruction.

No subacute thrombosis and femoral bleeding complications under full anticoagulation in 150 consecutive patients receiving non-heparin-coated intracoronary Palmaz-Schatz stents

Intracoronary stenting has been shown to have better immediate and long-term clinical outcomes and less restenosis than standard balloon angioplasty. However, the benefit was achieved at the cost of higher rates of coronary thrombosis, bleeding complications, the need for anticoagulation, and longer hospital stay. For the latter reasons there is a tendency to replace the anticoagulants by antiplatelet agents alone after stenting. However, we prospectively monitored 150 consecutive patients (133 men, 17 women, mean age 58.5 years) from two centers since February 1993. They all had coronary artery disease and underwent percutaneous implantation of non-heparin-coated Palmaz-Schatz coronary stents under a full but lower dose of anticoagulation. The femoral approach was used in all patients except one. In the 150 patients, 200 stents were implanted in 165 target arteries with 172 lesions. Stenting was performed without the guidance of intravascular ultrasonography; high-pressure poststenting inflation was used in only 17.3% of patients with less than optimal angiographic results. Coronary angiography was performed at baseline, immediately after the procedure, and after 6 months (mean 207 +/- 53.6 days SD) of stenting. The mean (+/-SD) coronary minimum luminal diameter increased from 0.52 0.31 mm to 3.13 +/- 0.42 mm immediately after stenting was performed and was 2.12 +/- 0.91 mm at 6 months. There was a 0% subacute thrombosis rate and a 0% femoral bleeding complication rate in the whole series. Only three (2%) major events occurred: one Q-wave myocardial infarction from closure of an angioplasty site distal to the stent on a very long lesion, one cerebrovascular accident, and one noncoronary-related death. The only patient who underwent the brachial approach had hematoma; otherwise no other minor event occurred. The mean hospital stay was 4.5 days in one of the two study centers. The long-term clinical follow-up rate was 97.3%. The mean (+/- SD) clinical follow-up period was 589 +/- 363 days. Clinical symptoms improved; the percentage of patients who had angina according to the Canadian Cardiovascular Society functional class II, III, and IV was 31.3%, 44.7%, and 4%, respectively, before stenting was performed and was reduced to 4.7%, 3.7%, and 0%, respectively at 6-month follow-up after stenting was performed. The 6-month angiographic restudy rate was 90.6%, and the restenosis rate was 18.3%. In contrast to other reported series, these results support the idea that with careful puncture technique and meticulous postoperative wound care, intracoronary stenting can be successfully performed with the patient under full anticoagulation without major risks of bleeding and femoral vascular complications. Furthermore with a full but comparatively lower dose of anticoagulation, subacute thrombotic complications can be reduced to 0% even with non-heparin-coated stents without the use of intravascular ultrasound guidance and without the use of adjunctive high-pressure poststenting inflation in most patients. The restenosis rate and long-term clinical outcomes remained very favorable.

Alterations of subtypes of cardiac adrenoceptors in old rat

AIM

To determine alterations of subtypes of myocardial adrenoceptors in senescence.

METHODS

Heart membrane preparations were made from 3- and 25-month old Wistar rats. Alpha 1- and beta-adrenoceptors were measured by radioligand, 125I-BE2254 and 125I-pindolol, binding assays, respectively.

RESULTS

In the old rat heart, alpha 1- and beta-adrenoceptor densities were declined from the young rats of 119 +/- 4 and 45.9 +/- 1.9 pmol L-1 to 70 +/- 6 and 36.4 +/- 1.6 pmol L-1 (P < 0.01), with a greater change in alpha 1-AR and in beta-AR. The ratio of alpha 1A/alpha 1B subtypes was decreased from the young rats of 39/61 to the old rats of 26/74 (P < 0.05).

CONCLUSION

The cardiac adrenoceptors are decreased with different extents in the different subtypes in old rats.

A new alpha 1-adrenergic receptor subtype with low affinity for 5-methyl-urapidil but insensitive to chlorethylclonidine

In the present study, we found that a novel alpha 1-adrenergic receptor subtype existed in rat heart by radioligand binding assay. This new alpha 1-adrenergic receptor subtype was different from alpha 1A-, alpha 1B-, alpha 1C-, and alpha 1D-subtypes reported recently. It had high affinity for WB4101, as the same of alpha 1A-subtype, but low affinity for 5-methyl-urapidil, and was insensitive to chlorethylclonidine.

Experimental studies of laser myocardial revascularization in rats

Myocardial revascularization by Nd: YAG laser used in rats with myocardial infarction was studied. The left coronary artery was ligated and the laser channels with a diameter of 300 microns were made immediately by 2.5-4.2 W lasersonics YAG unit. After 24 hours, the rats were killed. Evaluation included hemodynamics, lactate dehydrogenase of myocardium and myocardial infarct size. The results showed that laser myocardial revascularization reduced myocardial infarct size and enzyme leakage, and improved left ventricular function. The study may provide theoretical basis for the clinical applications of this new technique in the treatment of ischemic heart disease.

[Antiinflammatory drugs inhibit the elevation of plasma CGRP concentration in endotoxin shock in rats]

In the present study, we observed the effects of indomethacin, ibuprofen, naloxone and morphine on plasma CGRP concentration 3 h after endotoxin shock in conscious rats. The results showed that indomethacin, ibuprofen and naloxone significantly inhibited the elevation of plasma CGRP concentration as well as reduced the lesion in the intestine during endotoxin shock. However, morphine had no significant effect. The data are consistent with our hypothesis that prostaglandin, as one of the inflammatory mediators which increase in shock may be an important endogenous factor for triggering the CGRP release during endotoxin shock.

[Radioligand assay of beta adrenoceptors in lymphocytes isolated from rat spleen]

[3H]Dihydroalprenolol ([3H]DHA) was used to label beta-adrenoceptors in intact lymphocytes isolated from rat spleen. The binding conditions were investigated by the methods of L9 (3(4)) orthogonal analysis, the results showed the optimum binding conditions were pH 7.7, 1 x 10(8) lymphocytes.ml-1 and 10 min at 25 degrees C for incubation. On these conditions the [3H]DHA binding to beta-adrenoceptors was rapid (T1/2 2 min) and readily reversed by propranolol 1 mmol.L-1 (T1/2 4 min). [3H]DHA saturation experiments indicated a single class of site with a KD of 7.2 +/- 2.2 nmol.L-1 and Bmax of 81 +/- 28 fmol/10(7) lymphocytes (n = 3). Computer analysis of competition experiments with isoproterenol and epinephrine revealed two classes of sites. One site had high affinity for the [3H]DHA and comprised 60 +/- 5% of the total number of sites, whereas the other site had a lower affinity. The affinity of the high affinity site was about 3 orders of magnitude higher than that of the lower affinity site.

[Effects of thyroxine on IgM production and beta-adrenergic receptor on lymphocyte in mice]

The effects of thyroxine (L-T4) on the IgM production of splenocytes in mice induced by sheep red blood cell (SRBC) were investigated by means of spectrophotometry of quantitative hemolysis (QHS). The maximum binding site number (Bmax) and affinity (Kd) of beta-adrenergic receptors (beta-Adr. R.) on splenic lymphocytes of mice under the different thyroid functional status during immune response were determined by radio-ligand combination method. The IgM production and Bmax of beta- Adr. R. of splenic lymphocytes were increased in "hyperthyroid mice" and decreased in "hypothyroid mice" as compared with the control (P less than 0.01) during the 3rd to 5th day after immunization with SRBC, but affinity of beta-Adr. R. was not changed (P greater than 0.05). It is suggested that L-T4 could increase the IgM production in lymphocytes induced by SRBC in mice. The underlying mechanism seems to involve an increasing Bmax of beta-Adr. R. on the immune cell, thus enhancing its sensitivity to catecholamine.

Calcitonin gene-related peptide in the pathogenesis and treatment of hypertension

The present study demonstrated that the plasma calcitonin gene-related peptide (CGRP) concentration was lower but the CGRP content of abdominal aorta was higher in spontaneously hypertensive rats (SHR) than in normotensive rats (WKY), using specific CGRP radioimmunoassay (P less than 0.01). In eighteen patients with essential hypertension, the concentration of plasma CGRP was also much lower than that of normal subjects, suggesting that a decreased release of arterial CGRP might be a part of the pathogenesis of essential hypertension. In SHR, a significant decrease in blood pressure was found following intravenous injection of 2.5 micrograms/kg of CGRP; similarly, in seven patients with essential hypertension intravenous injection of CGRP (50 micrograms) could induce a significant hypotensive effect. These data suggest that CGRP is a new potential drug for the treatment of essential hypertension.