[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.

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 17β- 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.

[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.

[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.

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-, β1- and β2-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, β1-AR and β2-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.

Antitumor agents 294. Novel E-ring-modified camptothecin-4β-anilino-4'-O-demethyl-epipodophyllotoxin conjugates as DNA topoisomerase I inhibitors and cytotoxic agents

Two conjugates (1 and 2) of camptothecin (CPT) and 4β-anilino-4'-O-demethylepipodophyllotoxin were previously shown to exert antitumor activity through inhibition of topoisomerase I (topo I). In this current study, two novel conjugates (1E and 2E) with an open E-ring in the CPT moiety were first synthesized and evaluated for biological activity in comparison with their intact E-ring congeners. This novel class of CPT-derivatives exhibits its antitumor effect against CPT-sensitive and -resistant cells, in part, by inhibiting topo I-linked DNA (TLD) religation. An intact E-ring was not essential for the inhibition of TLD religation, although conjugates with an open E-ring were less potent than the closed ring analogs. This lower religation potency resulted in decreased formation of protein-linked DNA breaks (PLDBs), and hence, less cell growth inhibition. In addition to their impact on topo I, conjugates 1E, 2, and 2E exhibited a minor inhibitory effect on topo II-induced DNA cleavage. The novel structures of 1E and 2E may present scaffolds for further development of dual function topo I and II inhibitors with improved pharmacological profiles and physicochemical properties.

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.

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.

Selective inhibition of tumor microvascular permeability by cavtratin blocks tumor progression in mice

Tumor vasculature is hyperpermeable to macromolecules compared to normal vasculature; however, the relationship between tumor hyperpermeability and tumor progression is poorly understood. Here we show that a cell-permeable peptide derived from caveolin-1, termed cavtratin, reduces microvascular hyperpermeability and delays tumor progression in mice. These antipermeability and antitumor actions of cavtratin occur in the absence of direct cytostatic or antiangiogenic effects. Cavtratin blocks microvascular permeability by inhibiting endothelial nitric oxide synthase (eNOS), as the antipermeability and antitumor actions of cavtratin are markedly diminished in eNOS knockout mice. Our results support the concepts that hyperpermeability of tumor blood vessels contributes to tumor progression and that blockade of eNOS may be exploited as a novel target for antitumor therapy.

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.

[The preparation of Ag/AgCl nanoparticle and its resonance scattering spectroscopic study]

Putting the AgCl nanoparticle as crystal nucleus and in the condition of the existence of tri-sodium citrate, the Ag+, which covers the surface of AgCl nanoparticle, photochemically reduces to Ag and thus Ag/AgCl composite nanoparticle is obtained. The spectroscopic characters of Ag/AgCl nanoparticle in aqueous solution have been studied. There are two resonance scattering peaks at 310 and 590 nm, and an absorption peak at 400 nm.

[The determination of lorazepam in human urine by gas chromatography/nitrogen-phosphorus detector]

A method to assay lorazepam in human urine has been developed. After addition of hydroxyethylflurazepam (internal standard) and hydrolysis with beta-glucuronidase, the lorazepam and hydroxyethylflurazepam were extracted with ethyl ether at pH 10.8. The analysis was performed on an HP-5 capillary column with nitrogen-phosphorus detector(NPD). The detection limit and recovery of analytes in urine were 5 micrograms/L and (83.4 +/- 3.1)% respectively. The method was successfully applied to urine specimens collected from healthy human volunteers who have ingested 2 mg of lorazepam. The method was sensitive enough to assay urine specimen excreted at 32 h after taking the medicine by volunteers.

Local high-capacity adenovirus-mediated mCTLA4Ig and mCD40Ig expression prolongs recombinant gene expression in skeletal muscle

Multiple forms of muscular dystrophy are due to the absence of cytoskeletal muscle proteins that normally protect the integrity of muscle cells. The lack of any adequate treatments for these devastating diseases propels research toward the development of strategies for gene delivery to skeletal muscle. High-capacity adenoviral vectors (HC-AdV) devoid of all viral coding sequences have been developed to avoid expression of viral proteins by the gene therapy vector. However, the capsid proteins that are an essential component of the input viral vector and any residual helper virus in the vector preparation could induce an immune response. Furthermore, the therapeutic protein provided by a gene transfer vector presents the potential to induce an immune response in a patient who does not express a normal cellular protein due to genetic mutation. Therefore, we hypothesize that some immune suppression will be required with therapeutic gene delivery designed for the treatment of patients with inherited muscle diseases. In this study, we constructed and rescued three HC-AdVs expressing murine CTLA4Ig, murine CD40Ig, or both. The backbone vector without a gene insert was rescued as a negative control vector. The production of relevant proteins from each vector was determined in vitro. In vivo function of each of the immunosuppressant vectors was assayed by co-injection with an enhanced green fluorescent protein (EGFP)-expressing first-generation adenoviral vector (AdEGFP) into the tibialis anterior muscle of C57BL/10 mice. Higher levels of muscle EGFP expression were observed in animals receiving an immunosuppressant vector. Furthermore, the production of total anti-AdV and anti-EGFP antibodies was reduced in mice treated with each of the three immunosuppressant vectors. A second intramuscular administration of AdEGFP alone 4 weeks after the initial co-injection was successful in all immunosuppressant vector-treated groups, but not in the negative control vector-treated group. All groups had a high antibody response to adenoviral proteins after the second injection of AdEGFP alone, indicating that the initial co-injection did not tolerize against vector capsid antigens.

[Glutamate-related mechanism of ginsenosides against anoxic-ischemic brain damage]

AIM AND METHODS

To observe the antagonist effect of ginsenosides upon excitatory neurotoxicity of glutamate in rat hippocampal slices, and to observe the inhibitory and facilitated effects of ginsenosides upon glutamate release from cultured mice cortical neurons and upon glutamate uptake by cultured astrocytes, respectively, during simulated ischemia, in order to elucidate whether the protective effect of ginsenosides against anoxic-ischemic brain damage is related to reducing the excitatory neurotoxicity of glutamate.

RESULTS

The orthodromic population spikes (OPS) recorded in hippocampal slice decreased in amplitude and disappeared finally during 20-min glutamate (1 mmol/L) exposure, and recovered less 1 h after the end of this exposure. However, OPS recovered well after the use of ginsenosides at different concentrations, especially at 20 microg/ml. In cultured mice cortical neurons and astrocytes, glutamate released from neurons up to several times of control and its uptake by astrocytes decreased markedly during simulated ischemia, ginsenosides (20 microg/ml) could significantly inhibit glutamate release from neurons and facilitate glutamate uptake by astrocytes during the same ischemia exposure.

CONCLUSIONS

Reducing the excitatory neurotoxicity of glutamate may be an important mechanism of ginsenosides against anoxic-ischemic brain damage.

[Research of the extraction method of morphine from biological fluids]

A solid-phase extraction method of morphine from urine and blood has introduced. The effect of 5 SPE columns, 3 eluents and pH on morphine recovery has been investigated systematically. Derivative GC was used as a method of detection. The result showed that the column and the eluent of such as GDX-301, GDX-403 and C18 chloroform:isopropanol (9:1) had good behaviors to extraction of morphine. When GDX-301 was used as a sorbent, the recovery of morphine from urine was above 90% at pH 9, then went down with the increase of pH. While the recovery from blood was growing with the increase of pH, which reached above 90% in strong alkaline. The extraction method is simple, inexpensive, efficient and reproducible, which provides an effective and practical method to extract morphine and similar illicit drugs from biological fluids.

Rise in plasma oxidized glutathione by experimental hypoglycemia

Changes in plasma glutathione were investigated under hypoglycemic status. Twelve rabbits were randomly divided into hypoglycemic group (n=6) and saline-injected control group (n=6). Hypoglycemia was induced by intravenous injection of insulin as 10 U/kg and recovered by intravenous glucose injection after 60 minutes. In the control group, saline was intravenously injected in stead of insulin. Plasma levels of oxidized glutathione (GSSG) rose significantly (p<0.01) and remarkably decrease in plasma GSH/GSSG ratio (p<0.05) accompanying increase in serum enzymes in the hypoglycemic group. These results suggest that hypoglycemia might cause change in plasma GSSG which is related to increase of serum enzymes by hypoglycemia.

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.

Cardiac angiotensin converting enzyme and endothelin receptor in rats with chronic myocardial infarction

To ascertain the pathophysiological roles of the renin-angiotensin system and endothelin in heart failure and cardiac hypertrophy, we assessed changes in cardiac angiotensin converting enzyme (ACE) and endothelin-1 (ET-1) receptor using rats in which myocardial infarction was induced by left coronary ligation. The animals were decapitated 1 or 8 months after the operation. Cardiac ACE and ET-1 receptor were quantified by computerized in vitro autoradiography using 125I-MK351A (a lisinopril derivative) and 125I-ET-1. One month after myocardial infarction, cardiac weight and plasma atrial natriuretic peptide had increased in rats with infarction, compared to sham-operated controls, indicating the presence of chronic left ventricular dysfunction, although exchangeable body sodium and plasma renin activity were unchanged. Cardiac ACE increased markedly in the infarcted area and moderately in hypertrophied myocardium without any change in affinity compared to sham-operated rats. On the other hand, there was no change in cardiac ET-1 receptors in infarcted rats. The same results were found even at 8 months after myocardial infarction. The present study indicates that cardiac ACE may participate in tissue repair at the site of myocardial infarction and may also play a role in the pathophysiology of cardiac hypertrophy in rats with chronic heart failure. However, the present results do not reveal whether ET-1 receptor participates in the pathophysiology of cardiac hypertrophy in this model.

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.

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.

Plasma enzymic changes in insulin-induced hypoglycemia in experimental rabbits

In order to elucidate the effects of hypoglycemia on cardiac and skeletal muscle, plasma activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and creatine kinase (CK) were assessed in rabbits with hypoglycemia induced by i.v. injection of insulin. After hypoglycemia lasting for more than 30 min, the plasma levels of ALT, AST and LDH rose significantly in 4 out of 5 rabbits reaching a peak at 24 hr. The plasma activity of CK rose remarkably and reached a peak at 6 hr after insulin injection in all rabbits. These results suggest prolonged hypoglycemia may cause myocardial and/or skeletal muscle damage, which can be ascertained by measuring plasma activities of the related enzymes.

A cohort study of cancer among benzene-exposed workers in China: overall results

A large cohort study of 74,828 benzene-exposed and 35,805 unexposed workers employed between 1972 and 1987 in 12 cities in China were followed to determine mortality from all causes and the incidence of lymphohematopoietic malignancies and other hematologic disorders. Benzene-exposed study subjects were employed in a variety of occupations, including painting, printing, and the manufacture of footwear, paint, and other chemicals. All-cause mortality was similar in the benzene-exposed and unexposed comparison group. Statistically significant excess deaths were noted among benzene-exposed subjects for leukemia (RR = 2.3, 95% CP 1.1-5.0), malignant lymphoma (RR = 4.5, 95% CI: 1.3-28.4), and nonneoplastic diseases of the blood (RR = 95% CP 2.5-infinity), and a marginally significant excess was noted for lung cancer (RR = 1.4, 95% CI: 1.0-2.0). Risk was significantly elevated for the incidence of all lymphohematopoietic malignancies (RR = 2.6, 95% CI: 1.5-5.0), malignant lymphoma (RR = 3.5, 95% CI: 1.2-14.9), and leukemia (RR = 2.6, 95% CI.. 1.3-5.7). Among the leukemia subtypes, only acute myelogenous leukemia (AML) incidence was significantly elevated (RR = 3.1, 95% CI: 1.2-10.7), although nonsignificant excesses were also noted for chronic myelogenous leukemia (CML) (RR = 2.6, 95% CI: 0.7-16.9) and lymphocytic leukemias (RR = 2.8, 95% CI.. 0.5-54.5). Significant excesses were found for aplastic anemia (RR = infinity, 95% CI: 2.2-co) and myelodysplastic syndrome (RR = infinity, 95% CI: 1.7-infinity). Employment in benzene-associated occupations in China is associated with a wide spectrum of myelogenous and lymphocytic malignant diseases and related disorders. Investigations continue to assess the nature of these associations.

Blood flow velocity in the common carotid artery in humans during graded exercise on a treadmill

Cerebral blood volume flow and flow velocity have been reported to increase during dynamic exercise, but whether the two increase in parallel and whether both increases occur as functions of exercise intensity remain unsettled. In this study, blood flow velocity in the common carotid artery was measured using the Doppler ultrasound method in eight healthy male students during graded treadmill exercise. The exercise consisted of stepwise progressive increases and decreases in exercise intensity. The peak intensity corresponded to approximately 85% of maximal oxygen consumption. During this exercise, the heart rate (fc), mean blood pressure (BP) in the brachial artery and mean blood flow velocity (vcc) in the common carotid artery increased as functions of exercise intensity. At the peak exercise intensity, fc, BP and vcc increased by 134.5%, 20.5% and 51.8% over the control levels before exercise (P < 0.01), respectively. The resistance index (RI) and pulsatility index (PI) were determined from the velocity profile and were expected to reflect the distal cerebral blood flow resistance. The RI and PI increased during the graded exercise, but tended to decrease at the highest levels of exercise intensity. As vcc increased with increases in exercise intensity it would be expected that cerebral blood flow would also increase at these higher intensities. It is also suggested that blood flow velocity in the cerebral artery does not proportionately reflect the cerebral blood flow during dynamic exercise, since the cerebral blood flow resistance changes.

Blood flow velocity in common carotid artery in humans during breath-holding and face immersion

Blood flow velocity was measured in the common carotid artery of humans during breath-holding (BH) in the supine and upright positions, and during breath-hold face immersion (FIBH) in cold (20 degrees C) and warm (35 degrees C) water in the upright position with 90 degrees flexion of the upper body, to test the influences of the body position, facial immersion and temperature on changes in cerebral blood flow. Simultaneously, the heart rate (HR) and blood pressure (BP) under the same conditions, and the end-tidal PO2 and PCO2 (PETO2 and PETCO2) during supine BH, were also measured. Results showed that posture had no significant effect on the apneic HR. Bradycardia developed during cold FIBH, but not warm FIBH. The BP increased during BH in both positions, and during both cold and warm FIBH. The PETO2 decreased and the PETCO2 increased significantly at the end of BH. The blood velocity decreased transiently at the beginning of upright BH, but increased time-dependently during both supine and upright BH. Moreover, the velocity increased more during warm FIBH than during BH's, and even more during cold than warm FIBH. When bradycardia occurred during cold FIBH, the velocity integral per minute tended to decrease. These results suggest that the cerebral blood flow increases in these conditions of BH. This increase can be explained by the increase in PETCO2 and decrease in PETO2, possibly with a slight contribution from the increase in the BP.(ABSTRACT TRUNCATED AT 250 WORDS)

Cohort study among workers exposed to benzene in China: I. General methods and resources

Benzene is recognized internationally as a leukemogen, but the available data to clarify dose-response relationships and examine risks of malignancies other than leukemia are sparse. A collaborative study was therefore carried out to expand on a previous retrospective cohort mortality study of Chinese benzene-exposed workers. Methods and resources used in the 16-year follow-up of 74,828 benzene-exposed and 35,805 unexposed workers employed for any length of time during 1972-1987 in 712 factories in 12 cities in China are described. Details are provided of the study organization, assessment of benzene exposures since 1949, characterization of factories and workers by exposure status, city, and sex, identification and confirmation of cancers and other deaths, and quality control procedures. The distinguishing features of the study are discussed in relation to earlier cohort studies, and study limitations as well as strengths are presented.

Cohort study among workers exposed to benzene in China: II. Exposure assessment

This report describes a retrospective exposure assessment method used in a follow-up mortality study of workers exposed to benzene. The approach quantified historical exposure to benzene in a multi-industry, multicenter cohort, involving 672 factories in 12 cities in China. Historical exposure data were collected to obtain exposure information related to 1,427 work units (departments) and 3,179 unique job titles from benzene-producing or -using factories in which written records and other data sources were evaluated. The basic unit for exposure assessment was a factory/work unit/job title combination which was considered separately during each of seven calendar-year time periods between 1949 and 1987 for a total of 18,435 exposure assignments. Historical information collected to estimate exposure included benzene monitoring data; lists of raw materials and factory products, and the percentage of benzene in each; the total amount and dates of use of benzene or benzene-containing materials; use of engineering controls and personal protective equipment; and other available exposure information. Overall, 38% (ranging from 3% for the earliest periods to 67% for the last period) of the estimates were based primarily on benzene monitoring data. In the absence of job-specific benzene monitoring data for a given calendar period, measurement results or exposure estimates for similar jobs and/or other calendar periods were used in conjunction with other exposure information to derive estimates. Estimated exposure levels are presented by industries and occupations. The highest average exposures during 1949-1987 were observed for the rubber and plastic industry (30.7 ppm), and for rubber glue applicators (52.6 ppm).

Gender differences in hematopoietic and lymphoproliferative disorders and other cancer risks by major occupational group among workers exposed to benzene in China

Gender differences in risk for leukemia and other selected and combined disease categories were examined by major occupational category for 74,828 benzene-exposed workers compared to 35,805 unexposed workers from 12 cities in China. No significant differences in the relative risks for total mortality and cancer mortality were found between female and male benzene-exposed workers, although risks tended to be somewhat higher among male than among female employees. Both female and male workers in several occupational categories had notably increased risks for all hematopoietic and lymphoproliferative (HLP) malignant and nonmalignant disorders combined and for total leukemia. Variation in risk for HLP disorders by occupational category was observed in both genders, with highest risks for male and female chemical manufacturing workers, female nonproduction employees, and male printers. However, the numbers of leukemia and other HLP malignancies in each category were small. The findings suggest that both female and male benzene-exposed workers in several occupational categories experience excess leukemia and other HLP disorders with relatively minor gender differences. Although this population is one of the largest cohorts of benzene-exposed workers studied to date, evaluation of the observed variation in risk for HLP neoplasms among the occupational groups for workers of each gender is limited by the small numbers of these relatively rare malignancies.

Flow velocity in carotid artery in humans during immersions and underwater swimming

Heart rate and flow velocity in the common carotid artery were examined on eight subjects in various underwater conditions. The heart rate decreased more markedly during whole-body immersion than during head-out immersion. The end-diastolic flow velocity and the flow-velocity integral in a cardiac cycle during whole-body immersion increased more markedly than during head-out immersion. Differences in heart rate and flow velocity were not detected between sitting and prone positions in whole-body immersion. Heart rate increased at the beginning and after underwater swimming. The peak systolic flow velocity increased significantly after the end of underwater swimming. The flow-velocity integral in a cardiac cycle decreased during underwater swimming, but in a minute did not change significantly. These results suggest that facial immersion is important in eliciting pronounced carotid artery flow-velocity response in addition to the heart-rate response and that underwater exercise influences these responses. However, underwater posture apparently does not influence them.

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.

Changes in carotid blood flow and electrocardiogram in humans during and after walking on a treadmill

Blood flow velocity in the common carotid artery and the electrocardiogram were measured simultaneously by telemetry in seven male subjects during 20-min walking on a treadmill at an exercise intensity corresponding to a mean oxygen uptake of 26.0 (SD 2.9) ml.kg-1.min-1. The mean cardiac cycle was shortened from 0.814 (SD 0.103) s to 0.452 (SD 0.054) s during this exercise. Of this shortening, 73% was due to shortening of the diastolic period and 27% to shortening of the systolic period. In the relatively small shortening of the mean systolic period [from 0.377 (SD 0.043) s to 0.268 (SD 0.029) s], the isovolumetric contraction time was shortened by 56%. During exercise, the heart rate (fc) increased by 79.4% [from 74.3 (SD 9.3) beats.min-1 to 133.3 (SD 14.8) beats.min-1], and the peak blood velocity (S1) in the common carotid artery increased by 56.1% [from 0.82 (SD 0.10) m.s-1 to 1.28 (SD 0.11) m.s-1]. After exercise, the S1 decreased rapidly to the resting level. The fc decreased more slowly, still being higher than the initial resting level 5 min after exercise. The diastolic velocity wave and the end-diastolic foot decreased during exercise. The blood flow rate in the carotid artery increased transiently by 13.5% at the beginning of exercise [from 5.62 (SD 0.63) ml.s-1 to 6.38 (SD 0.85) ml.s-1] and by 26.5% at the end of the exercise period [from 5.62 (SD 0.63) ml.s-1 to 7.11 (SD 1.34) ml.s-1].(ABSTRACT TRUNCATED AT 250 WORDS)

Arrest of cell cycle progression of HeLa cells in the early G1 phase in K(+)-depleted conditions and its recovery upon addition of insulin and LDL

Cell cycle progression of synchronized HeLa cells was studied by measuring labeling of the nuclei with [3H]thymidine. The progression was arrested in a chemically defined medium in which K+ was replaced by Rb+ (Rb-CDM) but was restored upon addition of insulin and/or low density lipoprotein (LDL). Cells started DNA synthesis 12 hr after addition of insulin and/or LDL, regardless of the time of arrest, suggesting their arrest early in the G1 phase. After incubation of cells in Rb-CDM containing insulin or LDL singly for 3, 6, or 9 hr, replacement of the medium by that without an addition resulted in marked delay in entry of cells into the S phase, but in its replacement by medium containing both agents, the delay was insignificant. Synthesis of bulk protein, estimated as increase in the cell volume, was not strongly inhibited. From these results we conclude that cell cycle progression of HeLa cells in K(+)-depleted CDM is arrested early in the G1 phase and that the arrest is due to lack of some protein(s) required for entry into the S phase that is synthesized in the early G1 phase.

Changes in cardiac rhythm in man during underwater submersion and swimming studied by ECG telemetry

A previously reported method for electrocardiographic (ECG) telemetry in water using frequency-modulated current was improved to obtain more stable ECGs. The ECGs of seven healthy men were monitored using the improved method during and after whole-body submersion or underwater swimming. Bradycardia and arrhythmias were observed during the submersion, and transient tachycardia was detected after the start of underwater swimming, followed by bradycardia with arrhythmias. Three different types of arrhythmias were observed: sinus arrhythmia (SA), supraventricular extrasystole (SE) and ventricular extrasystole (VE). SA and SE tended to develop during the latter half of the period of submersion or underwater swimming, and especially after the restart of breathing. VEs were detected in only one subject during submersion, whereas they occurred in most subjects during and after underwater swimming. Individual variations were found in development of arrhythmias, one subject showing no arrhythmia. Bradycardia, SA and SE could depend on vagal suppression in underwater conditions, and VE may be related to the effect of muscular movement on cardiac function in addition to vagal inhibition.

Isolation and regional localization of the murine homeobox-containing gene Hox-3.3 to mouse chromosome region 15E

A murine homeobox-containing cDNA clone has been isolated from an adult spinal cord library. Using in situ hybridization and somatic cell genetics techniques, the newly isolated homeobox gene has been mapped to mouse chromosome region 15E. Because of its chromosomal location, we called this gene locus Hox-3.3. Nucleotide sequence analysis revealed that the Hox-3.3 gene represents the murine cognate of the human homeobox gene c8. The presumptive organization of the murine Hox-3 homeobox gene cluster is discussed.

The distribution of P elements in D. melanogaster along the coast of China studied by DNA hybridization method

The distribution of the P-M system in four local Drosophila melanogaster populations obtained in southern China has been examined by mating tests. There was no P strain. A HindIII fragment of the P element has been cloned, named as pPH 0.86, and used as probe in this study. The distribution of the P element itself in thirteen local D. melanogaster populations along the eastern coast of China has been studied by the method of DNA hybridization. It is found that all the populations obtained from the north of Shanghai carry P elements but few populations from the south of Shanghai carry P elements. In comparison with the mating test, the method of DNA hybridization is more direct and reliable. The origin and trends of distribution of P elements in China are discussed in this paper.