[Comparing the impact of left bundle branch area pacing and traditional left ventricular pacing on right heart function following dual-chamber pacemaker implantation].

Objective: To compare the effects of left bundle branch area pacing (LBBaP) versus traditional right ventricular pacing (RVP) on left ventricular function in patients after dual-chamber pacemaker implantation. Methods: A retrospective cohort study was conducted on patients who underwent dual-chamber pacemaker implantation from March 2017 to April 2021 in Beijing Anzhen Hospital. The patients were divided into the LBBaP group and RVP group based on the placement of the ventricular lead. Follow-up was conducted until March 2022, comparing baseline and follow-up echocardiographic parameters, pacing parameters, and the incidence and timing of complications between the two groups. The complications included ventricular electrode perforation, dislocation, pericardial effusion, tricuspid valve perforation, etc. Results: A total of 163 patients aged (68.3±13.5) years were included, including 82 (50.3%) men, with 80 patients in the LBBaP group and 83 in the RVP group. Baseline left ventricular end-diastolic diameter ((50.49±4.95) mm vs. (47.43±8.15) mm, P=0.01) and left atrium (LA) ((33.14±5.94) mm vs. (30.18±3.92) mm, P=0.001) in the LBBaP group were significantly higher than those in the RVP group. Follow-up LA diameter ((37.10±6.70) mm vs. (40.10±8.90) mm, P=0.016) showed a statistically significant difference in the LBBaP group compared to the RVP group. There was no statistically significant difference between the two groups in baseline QRS duration(P=0.490). Postoperative QRS duration in the LBBaP group was significantly lower ((110.69±24.01) ms vs. (139.65±29.85) ms, P<0.010). Intraoperative threshold in the LBBaP group was significantly higher ((0.83±0.32) V/0.48 ms vs. (0.71±0.23) V/0.48 ms, P=0.004), while impedance was lower ((754.53±205.59) Ω vs. (905.41±302.75) Ω, P<0.01). Comparing with the RVP group, postoperative ventricular pacing ratio (VP) ((87.39±20.92) % vs. (79.49±25.76) %, P=0.034), threshold ((0.90±0.38) V/0.48 ms vs. (0.69±0.27) V/0.48 ms, P<0.01) in the LBBaP group were higher, and impedance ((507.45±77.37) Ω vs. (620.52±197.29) Ω, P<0.01) in the LBBaP group was lower. Postoperative follow-up period was 5 to 51 months, with a median follow-up time of 17 months. No statistically significant difference in overall complications between the LBBaP and RVP groups was found (13.8% (11/80) vs. 7.2% (6/83), P>0.05). The median time to occurrence of complications after surgery was significantly earlier in the LBBaP group (29.74 (95%CI 27.21-32.26) months vs. 46.17 (95%CI 42.48-49.86) months, P=0.030). Conclusion: LBBaP demonstrates more stable pacing parameters, substantial improvement in clinical left ventricular function, with a relatively higher threshold compared to traditional RVP, and complications occurs relatively early.

[Role and potential value of circular RNAs in the occurrence of primary hepatic cancer].

Circular RNA is a class of non-coding RNAs, which are covalently closed and circular at both ends, showing dissimilar characteristics from linear RNA. Several studies have shown that circular RNAs play an important role in the occurrence and development of primary hepatic cancer. By combining with the latest research progress of this field at home and abroad, we summarized the mechanism regulating the occurrence and development of liver cancer, abnormal expression, and as potential molecular markers for disease diagnosis and treatment.

[Clinical results of Mei mini maze procedure for atrial fibrillation patients with previously failed catheter ablation].

Objective: To evaluate the efficacy of Mei mini maze procedure for treating atrial fibrillation (AF) patients with previously failed catheter ablation. Methods: Between August 2010 and May 2016, 48 AF (8 proximal AF, 15 persistent AF and 25 long-standing persistent AF) patients (29 males, 19 females, mean age: (62.5±7.3) years old) with previously 1-3 failed catheter ablation results were treated with Mei mini maze procedure in our department. Under thoracoscopic assistance, the procedure was performed through three ports on left chest wall, pulmonary vein isolation and ablations of the roof and posterior wall of left atrium was made by bipolar radiofrequency ablation. Ganglionic plexus ablation was made by the ablation pen. Left atrial appendage was excluded. Patients were followed at outpatient clinic and per telephone. Electrocardiogram, CT and echocardiography examinations were performed at 1, 3, 6 and 12 months post operation. The success rate of the procedure was analyzed by Kaplan-Meier curves and evaluated by the log-rank test. Results: Mean AF history was (8.1±6.3) years and left atria dimension was (44.1±6.2) mm in this patient cohort. All procedures were performed successfully in these 48 patients. Pericardial adhesions were dissected in 21 patients. Durations of the procedures were (142.3±35.6) minutes.There were no serious complications. The hospital stay was (9.3±1.8) days. Sinus rhythm was documented in 44 patients (91.7%) at discharge. The mean follow-up duration was (28.0±17.2) months. Thirty-eight patients (82.6%) were in sinus rhythm. There was no stroke, thrombus in the left atrium and stenosis of pulmonary vein during the follow-up. Sinus rhythm was achieved in 7 out of 8 paroxysmal AF patients, in 31 out of 38 non-paroxysmal AF patients, and in 13 out of 15 persistent AF patients. Kaplan-Meier curve showed that the success rate in the long-standing persistent AF group was lower than in the other two groups, but there was no statistical difference. Conclusions: Mei mini maze procedure has a high success rate for AF patients with previously failed catheter ablation history, which could completely isolate the bilateral pulmonary vein and left atrial posterior wall with good quality and integrity of ablation line, and left atrial appendage is also resected during the procedure.

Platelet-derived miR-142-3p induces apoptosis of endothelial cells in hypertension.

The dysfunction of endothelial cells (ECs) plays crucial roles in vascular remodeling during hypertension. Researches suggested that ECs are regulated by the circulating platelets in vivo, which may participate in abnormal EC apoptosis in hypertension. However the molecular mechanism in this process is still unclear. Here we focused on the microRNAs (miRs) in platelets, and detected the potential role and delivery mechanism of platelet-derived miRs in ECs. Using microarray, the differentially expressed profile of miRs between platelets and ECs was detected. The results revealed that compared with ECs, 67 miRs highly expressed in platelets including the most significant one- miR-142-3p. Since platelets are activated by thrombin in hypertension, we detected the miR-142-3p transferring mechanism of activated platelet, and proved that platelet-derived microparticles (PMPs), but not platelets directly, delivered miR-142-3p into ECs via cellular adherent. Furthermore, BCL2L1, an important molecule in cell apoptosis, was predicted to be a putative target of miR-142-3p by multiple algorithms. Dual luciferase reporter assays, as well as miR-142-3p mimics treatment were used to confirm the interplay between miR-142-3p and BCL2L1. Meanwhile, using in vivo hypertensive rat model, our results showed that the expression of platelet-derived miR-142-3p and the apoptosis were both significantly increased in ECs during hypertension. The present results suggested that platelet-derived miR-142-3p is delivered into ECs via PMPs, and may modulate the expression of target molecule- BCL2L1, which may subsequently display a negative function by modulating EC apoptosis in hypertension.

[Serological and pathological features of drug-induced liver injury and autoimmune hepatitis].

Objective: To investigate the differences and similarities between drug-induced liver injury (DILI) and autoimmune hepatitis (AIH) in serum biochemical parameters and liver pathology, and to provide some thoughts for clinical diagnosis and differentiation of these two diseases. Methods: A retrospective analysis was performed for the biochemical, immunological, autoantibody, and liver pathological data of 106 DILI patients and 63 AIH patients who were hospitalized, diagnosed, and treated in our hospital from January 2012 to October 2014. The patients' general data, biochemical parameters, immunological data, Ishak score, and qualitative changes in liver tissue were analyzed and compared. The Kruskal-Wallis test was used for comparison of nonparametric data between multiple groups, the Nemenyi test was used for comparison of nonparametric data between any two groups, the Wilcoxon rank sum test was used for comparison of Ishak scores, and the chi-square test was used for comparison of constituent ratio of categorical data. Results: There were significant differences between AIH group and DILI hepatocyte injury group/mixed-type DILI group in the following serum biochemical parameters: alanine aminotransferase (187.2 U/Lvs 1 326.5 U/L and 455.6,P< 0.05), aspartate aminotransferase (172.2 U/L vs 759.5 U/L and 349.5 U/L,P<0.05), alkaline phosphatase (209.3 U/L vs 157.3 U/L and 169.4 U/L,P< 0.05), gamma-glutamyl transferase (254.8 U/L vs 176.5 U/L and 170.5 U/L,P< 0.05), total bilirubin (37.2µmol/L vs 95.8µmol/L and 52.6µmol/L,P< 0.05), serum iron (18.9µmol/L vs 36.2µmol/L and 23.9µmol/L,P< 0.05), serum ferritin (122.5µmol/L vs 410.4µmol/L and 186.5µmol/L,P< 0.05), immunoglobulin G (18.4 g/L vs 12.6 g/L and 12.3 g/L,P< 0.05), and immunoglobulin M (1.8 g/L vs 1.3 g/L and 1.1 g/L,P< 0.05). There were also significant differences between AIH group and DILI hepatocyte injury group/mixed-type DILI group in the Ishak score for interface inflammation (2.2±0.8 vs 1.3±0.7 and 1.3±0.6,P< 0.05), Ishak score for portal inflammation (2.3±0.9 vs 1.5±0.7 and 1.4±0.8,P< 0.05), and fibrosis score (2.8±1.1 vs 1.5±0.7 and 1.3±0.7,P< 0.05). There were significant differences between AIH group and DILI hepatocyte injury group/mixed-type DILI group in the proportion of wax-like deposition (0 vs 29.2% and 34.5%, P <0.05) and proportion of iron deposition (11.1% vs 52.1% and 25.9%,P< 0.05). Conclusion: There are differences in biochemistry, immunology, and liver histology between DILI and AIH patients. AIH patients have more serious interface inflammation and portal inflammation and a higher fibrosis degree compared with DILI patients, while DILI patients have greater proportions of wax-like deposition and iron deposition compared with AIH patients.

Fibroblast growth factor-2 regulation of Sprouty and NR4A genes in bovine ovarian granulosa cells.

Fibroblast growth factors (FGFs) alter ovarian function, at least in part by inhibiting steroid hormone secretion and affecting survival of granulosa cells. The mechanism of action of FGFs in ovarian follicle cells is largely unknown; in the present study we identified the major pathways used by FGF2 in non-luteinizing granulosa cells cultured under serum-free conditions. FGF2 increased abundance of mRNA encoding SPRY1, 2, and 4, but not SPRY3. Common pathways employed by FGF2 in the regulation of SPRY1, 2, and 4, as demonstrated by immunoblot and inhibitor studies, included ERK1/2 and Akt signaling. In contrast, PKC activation was necessary for FGF2-stimulated expression of SPRY1 and 4, but not for SPRY2. Intracellular calcium flux is critical and sufficient for SPRY2 expression, but not for SPRY1 and 4. We also identified the orphan nuclear receptor NR4A1 as a potential early response gene in FGF2 signaling, whose expression, like that of SPRY2, is critically dependent on calcium signaling. Together, these data identify FGF2-target genes in follicular granulosa cells, and demonstrate alternative pathway use for the differential control of SPRY genes.

Occurrence of Chilli veinal mottle virus in Nicotiana tabacum in Yunnan, China.

Flue-cured tobacco (Nicotiana tabacum) is an important crop in Yunnan Province, China. During a survey in July 2010, tobacco plants (N. tabacum cv. Yunyan 85) in the fields near Dali County in the northwest Yunnan Province of China had symptoms of chlorosis along leaf veins and later showed symptoms of white or brown necrosis along the veins. In 10 surveyed fields in Baizhishu Village in the city of Weishan, a commercial tobacco field (10 ha) developed virus-like disease symptoms; the incidence of affected plants ranged from 0.5 to 3%, which caused obvious economic losses. An isolate (YN75) was collected at random from five symptomatic leaves sampled from five plants. Negative staining of crude extracts of the infected leaves and subsequent electron microscopy revealed flexuous rods of 12 to 13 × 750 nm. Pinwheel-like inclusion bodies were abundant in thin sections of infected leaves. The particle size suggested a species of Potyviridae. Thus, the isolate was assayed in double antibody sandwich-ELISA (Agdia, Elkhart, IN) for the presence of Potato virus Y, Tobacco etch virus, and Tobacco vein mottling virus. All antigens gave negative results. Total RNA was extracted from leaves and tested by reverse transcription (RT)-PCR. The primer M4-T (5'-GTT TTC CCA GTC ACG ACT TTT TTT TTT TTT TT-3') was employed for cDNA synthesis described by Chen et al (1). The primer set ChiVMV-F (5'-TAG TTG YGC ATA C (C/G) C AGG AGA GAG-3')/M4 (5'-GTT TTC CCA GTC ACG AC-3') is complimentary to the region of coat protein and 3'-untranslated region of Chilli veinal mottle virus (ChiVMV), respectively. The expected 1,189-bp fragments were amplified from RNA templates and the amplicon was cloned and sequenced (GenBank Accession No. HQ218936). Comparisons of amplicons with the amino acid sequence available in the NCBI database using BLAST showed 91.4% identity with ChiVMV from India (GenBank Accession No. EF213688) and 90.7% with ChiVMV from Taiwan (Accession No. DQ854950). The virus particle size, RT-PCR results, and sequence data revealed that these tobacco plants were infected by ChiVMV. To our knowledge, this is the first report of ChiVMV infecting N. tabacum in China. Reference: (1) J. Chen et al. Arch. Virol. 146:757, 2001.

Changed expression of microRNAs may predict postoperative atrial fibrillation in patients with cardiac surgery.

OBJECTIVE: Changes of microRNAs (miRNAs) may contribute to the pathogenesis and progression of postoperative atrial fibrillation (POAF) in patients undergoing cardiac valve surgery. This study aimed to measure the expression levels of miRNAs in peripheral blood, as well as their target mRNAs, in POAF patients and normal controls (non-POAF), and to evaluate the potential of miRNAs as promising biomarkers to predict POAF. PATIENTS AND METHODS: The expression of miRNAs in peripheral blood, including miR-27b, miR-133a, miR-328, miR-499 and their target mRNAs, was analyzed in 109 POAF patients and 96 non-POAF patients via quantitative real-time polymerase chain reaction (RT-PCR). We compared differences between the two groups and also analyzed the treat reaction to amiodarone. RESULTS: All miRNAs in POAF patients were significantly highly expressed. Compared to non-POAF, the expression of miR-27b, miR-133a, miR-328, miR-499 increased in both groups of POAF patients, and miR-499 was the only upregulated miRNAs in the amiodarone - group versus amiodarone + group and non-POAF. Among the upregulated miRNAs, miR-499 expression significantly changed in amiodarone + and amiodarone - patients (p = 0.005). The ROC curve analysis revealed that miR-499 might be a potential therapeutic response biomarker. The miRNA-mRNA interactions revealed 10 mRNAs regulated by miR-27b, miR-133a, and miR- 499. CONCLUSIONS: We found an expression on miR-133a, miR-27b, miR-328, and miR-499 was significantly different between these groups, with a high expression being observed in POAF patients compared to non-POAF patients. Further, the present results showed that miR-499 was significantly upregulated in amiodarone - patients, compared to non-POAF, and amiodarone + patients. This finding indicates that miR-499 may be a potential biomarker for predicting the occurrence of POAF after cardiac valve surgery and treat the reaction to amiodarone.

Changed expression of microRNAs may predict postoperative atrial fibrillation in patients with cardiac surgery.

The article "Changed expression of microRNAs may predict postoperative atrial fibrillation in patients with cardiac surgery, by Z.-W. Xu, Z.-L. Jiang, Z. Fu, S. Huang, published in Eur Rev Med Pharmacol Sci 2021; 25 (1): 287-292-DOI: 10.26355/eurrev_202101_24394-PMID: 33506917" has been withdrawn from the authors since the results provided are not complete enough. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/24394.

Rhodiola sacra aqueous extract (RSAE) improves biochemical and sperm characteristics in cryopreserved boar semen.

Although Rhodiola sacra aqueous extract (RSAE) has been used in many studies as an antioxidant, its effects on semen characteristics and its antioxidant properties during cryopreservation of boar sperm have never been evaluated. Semen was collected from five Duroc boars (2-4-year-old) twice weekly and frozen-thawed in extender with RSEA. Motion characteristics were assessed with a computer-aided semen analysis (CASA) system, whereas other sperm quality end points were assessed by routine methods. The effective concentration of RSEA in extender ranged from 4 to 8mg/L and the effect of RSEA on sperm quality was better in glycerol-free extender than extender containing glycerol (P<0.05). In frozen-thawed boar semen, there was a direct correlation (P<0.05) between RSEA concentration and glutathione (GSH) concentrations, mitochondrial activity, and hypoosmotic swelling test (HOST), and an inverse correlation (r=-0.982, P<0.05) between RSEA concentration and malondialdehyde (all end points were significantly higher at 6mg/L than in the control group). In summary: (i) the effective concentration of RSEA in extender ranged from 4 to 8mg/L; (ii) the effect of RSEA on sperm quality was better in extender without glycerol; and (iii) there was a significant correlation between RSEA concentrations and concentrations of GSH and MAD in frozen-thawed boar semen (antioxidant effects of RSEA were concentration-dependent). Further studies are needed to define the active ingredient in RSEA that protects boar sperm against ROS.

The cryoprotective effect of trehalose supplementation on boar spermatozoa quality.

In order to improve boar sperm quality during frozen-thawed process, the influence of the presence of trehalose on success of cryopreservation of boar sperm were investigated. We evaluated freeze-thawing tolerance of boar spermatozoa in a base cooling extender with the addition of different trehalose concentrations (0, 25, 50, 100 and 200 mm), and try to determine the optimum concentration of trehalose. We chose sperm motility, mitochondrial activity, acrosome integrity and membrane integrity as parameters to evaluate cryopreservation capacity of boar spermatozoa. We obtained the best results for 100 mm trehalose-supplemented extenders, with values of 49.89% for motility, 44.69% for mitochondrial activity, 66.52% for acrosome integrity and 44.61% for membrane integrity, while freeze-thawing tolerance diminished significantly for 200 . The synergic effect of trehalose and glycerol resulted in better cryosurvival of boar spermatozoa than that of a single cryoprotectant. In conclusion, when trehalose-supplementation was added up to 100 mm, trehalose confers a greater cryoprotective capacity to the extender, and the sperm motility, mitochondrial activity, membrane integrity and acrosome integrity parameters were significantly improved during frozen-thawed process.

Protective effects of trehalose on frozen-thawed ovarian granulosa cells of cattle.

In this study, trehalose was investigated for its cryoprotective effects on ovarian granulosa cells (bGCs) of cattle. Five concentrations of trehalose at 0, 0.2, 0.4, 0.6 and 0.8 mol/L were added to the cryopreservation medium of bGCs, and the effects on the quality of frozen-thawed bGCs were assessed. The results indicate that the use of cryopreservation medium containing 0.2 and 0.4 mol/L of trehalose resulted in a greater rate of bGC viability compared to those of other groups (P<0.05). Culturing with trehalose at 0.2 and 0.4 mol/L increased 17ß- estradiol (E2)and decreased progesterone (P4)production (P < 0.05) in post-thawed bGCs. Compared with the control group, the intracellular Ca2+ concentrations of frozen-thawed bGCs were less in all treatment groups (P<0.05), and the least Ca2+ concentration was observed in the group containing 0.4 mol/L trehalose. The plasma membrane potentials of frozen-thawed bGCs were greater in the groups with 0.2 and 0.4 mol/L trehalose, and the group treated with 0.4 mol/L trehalose had the greatest membrane potential in comparison to other groups (P < 0.05). The relative abundance of the CYP19 mRNA in frozen-thawed bGCs was greater in the groups containing 0.2, 0.4 and 0.6 mol/L trehalose, and relative abundances of FSHR and BCL2 mRNA were greater in the group of bGCs treated with 0.2 mol/L trehalose (P<0.05). Trehalose treatment at 0.4, 0.6 and 0.8 mol/L had an inhibitory effect on BAX gene transcription in frozen-thawed bGCs (P<0.05). In summary, trehalose exhibited a greater cryoprotective effect on bGCs than basic cryopreservation medium.

The differentiation of beige adipocyte in pericardial and epicardial adipose tissues induces atrial fibrillation development.

OBJECTIVE: Growing evidence has identified that excessive accumulation of pericardial adipose tissues (PAT) and epicardial adipose tissues (EAT) is associated with atrial fibrillation (AF) development. Moreover, beige adipocytes, present in PAT and EAT, have been proved beneficial in consumption of fatty acid and promotion of weight lose by nonshivering thermogenesis. The objective of this prospective, observational study was to reveal the potential association between beige adipocytes and AF development. PATIENTS AND METHODS: Fat tissues from subcutaneous adipose tissue (SAT), PAT and EAT were obtained from 70 AF and 30 sinus rhythm patients. Hematoxylin and eosin (H&E) staining were performed to analyze morphological changes in fat tissues. Real-time PCR was performed to identify mRNA expression of unique uncoupling protein-1 (UCP-1). Western blotting and immunohistochemistry (IHC) were performed to determine protein expression of UCP-1. RESULTS: Our results indicated that pericardial and epicardial adipocytes in AF patients demonstrated white-like change tendency and had lower expression of UCP-1 when compared to sinus rhythm patients. Additionally, the decrease of UCP-1 mRNA expression in PAT and EAT, together with LA enlargement, were independent risk factors of AF. Further, UCP-1 mRNA expression in EAT, but not in PAT, have a significant correlation with LA diameter. The function of nonshivering thermogenesis in PAT and EAT was impaired in AF patients, and this dysfunction in EAT had a great correlation with LA dilation. CONCLUSIONS: Our data provide a new therapeutic target for LA remodeling and AF treatment.

Effects of olmesartan therapy on the expression of lung adrenoceptors in rats with chronic heart failure.

INTRODUCTION: Adrenergic receptors (AR) play important roles in regulating lung function. However, there are few reports concerning AR expression and the protective effect of angiotensin II receptor blockers (ARB) on the lung in chronic heart failure (CHF). In this study, we aimed to investigate the protective effects of the ARB olmesartan on the lung in CHF. MATERIALS AND METHODS: Wistar rats were randomly divided into four groups: normal control, sham-operated rats, rats with CHF induced by ligating the left anterior descending coronary arteries, and rats with CHF treated with olmesartan (1 mg/kg) once daily for 8 weeks. Heart function, plasma renin activity (PRA) and angiotensin II (Ang II) levels, lung microscopic structure inspection and mRNA and protein expressions of α1A-, ß1- and ß2-AR in lung were tested. RESULTS: Compared with the CHF group, PRA and Ang II levels were decreased while heart function and mRNA and protein expression of α1A-AR, ß1-AR and ß2-AR were up-regulated in the olmesartan group (p<0.05 or p<0.01). The inflammation and cell proliferation in CHF lung tissue were reduced in the olmesartan group. CONCLUSION: Olmesartan may play a beneficial role in protecting lung in CHF by up-regulating AR and decreasing levels of PRA and Ang II.

Protein kinase C epsilon is involved in ethanol potentiation of glycine-gated Cl(-) current in rat neurons of ventral tegmental area.

Previously, we demonstrated that ethanol potentiates glycine current (I(Gly)) in 35% of neurons freshly isolated from the ventral tegmental area (VTA) of rats (J. Pharmacol. Exp. Ther. 296 (2001) 77). In the present study, we examined the role of protein kinase C (PKC) in this action of ethanol on VTA neurons from young rats. Extracellular ethanol and intracellular ATP-gamma-S when applied separately potentiated I(Gly). However, ethanol potentiation of I(Gly) was significantly reduced in neurons dialyzed with 2 mM ATP-gamma-S. Phorbol-12-myristate-13-acetate (PMA, 10 nM), a PKC activator also increased I(Gly) and reduced ethanol potentiation of I(Gly). In addition, GF109203X (0.2 microM), a PKC inhibitor antagonized the potentiation effects produced either by PMA or by ethanol. Thus, ethanol potentiation of I(Gly) may be associated with PKC activation. While intracellular application of 1,2-bis(aminophenoxy)-ethane-N,N,N,N'-tetraacetic acid, a Ca(2+) chelator or Gö6976, an inhibitor of Ca(2+)-dependent PKC had no appreciable effect on ethanol potentiation of I(Gly), translocation inhibitor peptide (PKC(epsilon)-TIP) (500 nM) significantly reduced ethanol potentiation, an action the translocation inhibitor peptide negative control (PKC(epsilon)-TIP-NC) (500 nM) did not have. These results suggest that the activation of PKC(epsilon) isoenzyme contributes to ethanol-induced potentiation of GlyR function.

Genistein directly blocks glycine receptors of rat neurons freshly isolated from the ventral tegmental area.

The effects of tyrosine kinase inhibitors on the glycine-induced current (I(Gly)) were studied in rat neurons freshly isolated from the ventral tegmental area (VTA). Genistein reversibly and concentration-dependently depressed I(Gly), with an IC(50) of 13 microM. Preincubation with genistein had no effect on I(Gly), indicating that genistein is effective only when glycine is bound to the receptor and channels are most likely open. Genistein depressed maximum I(Gly) without significantly changing the EC(50) for glycine. Genistein-induced inhibition of I(Gly) was sensitive to membrane voltage, being greater at positive membrane potentials. A kinetic analysis indicated that genistein lengthens the time constant of I(Gly) activation, but has no effect on deactivation or desensitization. When genistein was rapidly washed out, a transient rebound current probably reflected a faster dissociation of genistein, with respect to glycine. Results of competition experiments suggest that genistein acts on the same region of the glycine receptor as picrotoxin. Daidzein, an analog of genistein that does not act on protein kinases, also inhibited I(Gly). Co-application of lavendustin A, a specific inhibitor of tyrosine kinase, had no effect on I(Gly). Our results extend to neurons isolated from the VTA, the previous finding that genistein directly inhibits glycine receptors of hypothalamic brain slices.

Indirect validation of benzene exposure assessment by association with benzene poisoning.

We present a validation study of a quantitative retrospective exposure assessment method used in a follow-up study of workers exposed to benzene. Assessment of exposure to benzene was carried out in 672 factories in 12 cities in China. Historical exposure data were collected for 3179 unique job titles. The basic unit for exposure assessment was a factory/work unit/job title combination over seven periods between 1949 and 1987. A total of 18,435 exposure estimates was developed, using all available historical information, including 8477 monitoring data. Overall, 38% of the estimates were based on benzene monitoring data. The highest time-weighted average exposures were observed for the rubber industry (30.7 ppm) and for rubber glue applicators (52.6 ppm). Because of its recognized link with benzene exposure, the association between a clinical diagnosis of benzene poisoning and benzene exposure was evaluated to validate the assessment method that we used in the cohort study. Our confidence in the assessment method is supported by the observation of a strong positive trend between benzene poisoning and various measures, especially recent intensity of exposure to benzene.

Mortality among benzene-exposed workers in China.

A large cohort of 74,828 benzene-exposed and 35,805 nonexposed workers employed between 1972 and 1987 in 12 cities in China was followed to determine mortality from all causes. Benzene-exposed study subjects were employed in a variety of occupations including coating applications, and rubber, chemical, and shoe production. Mortality was slightly increased among workers with greater cumulative exposure to benzene (ptrend < 0.05), but this excess was largely due to cancer deaths (ptrend < 0.01). Deaths due to lymphatic and hematopoietic malignancies (ptrend = 0.01) and lung cancer (ptrend = 0.01) increased with increasing cumulative exposure to benzene. Investigations continue to relate benzene exposure to specific lymphatic and hematopoietic malignancies and other causes of death.

Muscle damage induced by experimental hypoglycemia.

To determine organ damage due to hypoglycemia, we studied the effects of insulin dose and hypoglycemia duration on serum enzyme activity in rabbits. Thirty rabbits were randomly divided into five groups according to hypoglycemia duration and insulin dose: A2, hypoglycemia for 30 minutes with 2 U/kg insulin; A10, hypoglycemia for 30 minutes with 10 U/kg insulin; B2, hypoglycemia for 60 minutes with 2 U/kg insulin; B10, hypoglycemia for 60 minutes with 10 U/kg insulin; and C, no hypoglycemia with 10 U/kg insulin and 50% glucose. Insulin-induced hypoglycemia was reversed by intravenous injection of glucose. Alterations in serum enzyme activity and creatine kinase (CK) isoenzyme distribution were determined before and after insulin injection. Serum CK activity increased significantly in all hypoglycemic groups compared with preinjection values, and tended to remain high for 24 hours in both groups A10 and B10. Serum activity of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) increased only in group B10. In addition, the level of band 4 of serum CK isoenzymes, which exists predominantly in skeletal muscle and myocardium, increased significantly in group B10. These results suggest that the increase in both serum enzyme and CK band 4 isoenzyme activities during hypoglycemia is primarily due to damage in muscle rather than liver, and that the hypoglycemia duration and insulin dosage may influence the extent of organ damage.

Diameter-defined Strahler system and connectivity matrix of the pulmonary arterial tree.

For modeling of a vascular tree for hemodynamic analysis, the well-known Weibel, Horsfield, and Strahler systems have three shortcomings: vessels of the same order are all treated as in parallel, despite the fact that some are connected in series; histograms of the diameters of vessels in the successive orders have wide overlaps; and the "small-twigs-on-large-trunks" phenomenon is not given a quantitative expression. To improve the accuracy of the hemodynamic circuit model, we made a distinction between vessel segments and vessel elements: a segment is a vessel between two successive nodes of bifurcation; an element is a union of a group of segments of the same order that are connected in series. In an equivalent circuit, all elements of the same order are considered as arranged in parallel. Then, we follow the ordering method of Horsfield and Strahler, with introduction of an additional rule for the assignment of order numbers. If Dn and SDn denote the mean and standard deviation of the diameters of vessels of order n, then our rule divides the gap between Dn--SDn and Dn--1 + SDn--1 evenly between orders n and n--1. Finally, we introduced a connectivity matrix with a component in the mth row and the nth column that is the average number of vessels of order m that grow out of the vessels of order n. This method was applied to the rat. We found that the rat pulmonary arterial tree has 11 orders of vessels and that the geometry is fractal within these orders. The ratios of diameters, lengths, and numbers of elements in successive orders are 1.58, 1.60, and 2.76, respectively. The connectivity matrix reveals interesting features beyond the fractal concept. New features are found in the variation of the total cross-sectional area of elements with order numbers.