Effect of H1-antagonists on spatial memory deficit evaluated by 8-arm radial maze in rats

AIM

To evaluate effects of certain H1-antagonists on spatial memory with 8-arm radial maze performance of rats.

METHODS

Eight-arm radial maze performance was used to measure spatial memory in rats.

RESULTS

Chronic treatments of classical H1-antagonists, diphenhydramine (5 mg/kg) and pyrilamine (20 mg/kg) impaired acquisition memory process regarding both parameters of radial maze performance. In addition, the memory retrieval process was also impaired significantly by a single administration of diphenhydramine (5, 10 mg/kg) and pyrilamine (50 mg/kg). However, the newly developed H1-antagonist, epinastine caused no appreciable effect on both acquisition and retrieval memory even at a high dose of 50 mg/kg. The memory deficit induced by diphenhydramine (10 mg/kg) or pyrilamine (50 mg/kg) was reversed by tacrine (1 mg/kg).

CONCLUSION

Histamine H(1)-receptors plays a certain role in spatial cognition, and its action may be due to both histaminergic and cholinergic neurons.

Exposure to silica and silicosis among tin miners in China: exposure-response analyses and risk assessment

OBJECTIVES

To investigate the risk of silicosis among tin miners and to investigate the relation between silicosis and cumulative exposure to dust (Chinese total dust and respirable crystalline silica dust).

METHODS

A cohort study of 3010 miners exposed to silica dust and employed for at least 1 year during 1960-5 in any of four Chinese tin mines was conducted. Historical total dust data from China were used to create a job exposure matrix for facility, job title, and calendar year. The total dust exposure data from China were converted to estimates of exposure to respirable crystalline silica for comparison with findings from other epidemiological studies of silicosis. Each worker's work history was abstracted from the complete employment records in mine files. Diagnoses of silicosis were based on 1986 Chinese pneumoconiosis Roentgen diagnostic criteria, which classified silicosis as stages I-III-similar to an International Labour Organisation (ILO) classification of 1/1 or greater.

RESULTS

There were 1015 (33.7%) miners identified with silicosis, who had a mean age of 48.3 years, with a mean of 21.3 years after first exposure (equivalent to 11.0 net years in a dusty job). Among those who had silicosis, 684 miners (67.4%) developed silicosis after exposure ended (a mean of 3.7 years after). The risk of silicosis was strongly related to cumulative exposure to silica dust and was well fitted by the Weibull distribution, with the risk of silicosis less than 0.1% when the Chinese measure of cumulative exposure to total dust (CTD) was under 10 mg/m(3)-years (or 0.36 mg/m(3)-years of respirable crystalline silica), increasing to 68.7% when CTD exposure was 150 mg/m(3)-years (or 5.4 mg/m(3)-years of respirable crystalline silica). Latency period was not correlated to the risk of silicosis or cumulative dose of exposure. This study predicts about a 36% cumulative risk of silicosis for a 45 year lifetime exposure to these tin mine dusts at the CTD exposure standard of 2 mg/m(3), and a 55% risk at 45 years exposure to the current United States Occupational Safety and Health Administration and Mine Safety and Health Administration standards of 0.1 mg/m(3) 100% respirable crystalline silica dust.

CONCLUSIONS

A clear exposure-response relation was detected for silicosis in Chinese tin miners. The study results were similar to most, but not all, findings from other large scale exposure-response studies.

[Analysis on genetic polymorphism of mtDNA in endurance athletes and sedentary subjects]

AIM

To analysis the sequence variation of the origin region (D-loop) of mitochondrial DNA (mtDNA) in elite endurance athletes and sedentary subjects in order to find the genetic markers related with performance.

METHODS

Using a new established PCR method by virtue of tracing sample analysis, the restricted fragment length polymorphism (RFLP) of D-loop in mtDNA was assessed in 76 elite Chinese endurance athletes (EEA), 33 endurance athletes with average-level(GEA) and 20 sedentary control(sc).

RESULTS

There is a significant difference in distribution of the polymorphism in mtDNA D-loop between the EEA and SC(chi 2 = 33.3, P < 0.01).

CONCLUSION

The sequence variation of D-loop region of mtDNA in the elite endurance athletes may contribute to the individual difference in aerobic performance and trainability.

Non-malignant respiratory diseases and lung cancer among Chinese workers exposed to silica

The objective of this study was to explore whether a medical history for non-malignant respiratory disease contributes to an increased lung cancer risk among workers exposed to silica. We analyzed data from a nested case-control study in 29 dusty workplaces in China. The study population consisted of 316 lung cancer cases and 1356 controls matched to cases by facility type and decade of birth who were alive at the time of diagnosis of the index case and who were identified in a follow-up study of about 68,000 workers. Age at first exposure and cigarette smoking were accounted for in the analysis. Smoking was the main risk factor for both lung cancer and chronic bronchitis. Lung cancer risk showed a modest association with silicosis and with cumulative silica exposure, which did not vary by history of previous pulmonary tuberculosis. Among subjects without a medical history for chronic bronchitis or asthma, lung cancer risk was associated with silicosis (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.1 to 2.2), and it was increased in each quartile of cumulative silica exposure. However, risk was not elevated in the highest quartile (OR, 1.3, 1.6, 1.8, 1.4). Among subjects with a medical history for chronic bronchitis or asthma, lung cancer risk was associated with neither silicosis (subjects with chronic bronchitis: OR, 0.6; subjects with asthma: OR, 0.4) nor with silica exposure. In this study population, we observed a modest association of both silicosis and cumulative exposure to silica with lung cancer among subjects who were not previously diagnosed with chronic bronchitis or asthma, but not among subjects who had a medical history for either disease. Risk of lung cancer associated with silicosis or cumulative exposure to silica did not vary by previous medical history of pulmonary tuberculosis.

Distinct leukemia phenotypes in transgenic mice and different corepressor interactions generated by promyelocytic leukemia variant fusion genes PLZF-RARalpha and NPM-RARalpha

Acute promyelocytic leukemia (APL) is characterized by a specific chromosome translocation involving RARalpha and one of four fusion partners: PML, PLZF, NPM, and NuMA genes. To study the leukemogenic potential of the fusion genes in vivo, we generated transgenic mice with PLZF-RARalpha and NPM-RARalpha. PLZF-RARalpha transgenic animals developed chronic myeloid leukemia-like phenotypes at an early stage of life (within 3 months in five of six mice), whereas three NPM-RARalpha transgenic mice showed a spectrum of phenotypes from typical APL to chronic myeloid leukemia relatively late in life (from 12 to 15 months). In contrast to bone marrow cells from PLZF-RARalpha transgenic mice, those from NPM-RARalpha transgenic mice could be induced to differentiate by all-trans-retinoic acid (ATRA). We also studied RARE binding properties and interactions between nuclear corepressor SMRT and various fusion proteins in response to ATRA. Dissociation of SMRT from different receptors was observed at ATRA concentrations of 0.01 microM, 0.1 microM, and 1.0 microM for RARalpha-RXRalpha, NPM-RARalpha, and PML-RARalpha, respectively, but not observed for PLZF-RARalpha even in the presence of 10 microM ATRA. We also determined the expression of the tissue factor gene in transgenic mice, which was detected only in bone marrow cells of mice expressing the fusion genes. These data clearly establish the leukemogenic role of PLZF-RARalpha and NPM-RARalpha and the importance of fusion receptor/corepressor interactions in the pathogenesis as well as in determining different clinical phenotypes of APL.

[Phospholipase D and inflammation]

Phospholipase D (PLD) is widely distributed in mammalian cells, where it is regulated by a variety of extracellular signals. Its major substrate is phosphatidylcholine (PC), which is hydrolyzed to phosphatidic acid (PA) and choline. The PLD-catalysed PC hydrolysis is believed to be an important mechanism of signal transduction in cells. More and more lines of evidence indicate that PLD is tightly involved in inflammation. This review introduces the recent advances of PLD in respiratory burst, degranulation and arachidonic acid release.

Extracorporeal immunoadsorption compared to avidin chase: enhancement of tumor-to-normal tissue ratio for biotinylated rhenium-188-chimeric BR96

Based on the biodistribution and kinetics of biotinylated 188Re-chimeric BR96 (chiBR96), the enhancement of the tumor-to-normal tissue (T/N) radioactivity ratio using extracorporeal immunoadsorption (ECIA) was evaluated and compared with that of avidin "chase" in colon carcinoma-isografted Brown Norwegian rats.

METHODS

Extracorporeal immunoadsorption (ECIA) was performed 6 or 12 hr after intravenous administration of biotinylated 188Re-chiBR96. Radioactivity redistribution was investigated just after ECIA [8 or 14 hr postinjection of the antibody] and 40 or 34 hr after ECIA performance (48 hr postinjection). Avidin was administered intraperitoneally at 6 hr postinjection. Tumor radioactivity uptake and T/N activity ratios of biotinylated 188Re-chiBR96 were compared using ECIA and avidin chase and were also compared with controls.

RESULTS

Both ECIA and avidin chase can rapidly increase the radioactivity tumor-to-blood ratio without significantly interfering with the tumor uptake. ECIA at 8 hr postinjection increased the T/N ratios in blood-rich tissues, such as liver and bone marrow, from 6 and 8 to 10 and 18, respectively. Corresponding T/N ratios at 14 hr increased from 9 and 10 to 24 and 36. In contrast, when avidin chase was used, there were no T/N improvements, except in blood. Moreover, avidin chase caused a significant accumulation of radioactivity in the liver.

CONCLUSION

The ECIA approach, with direct removal of unbound circulating biotinylated 188Re-chiBR96, thus can rapidly improve and maintain T/N ratios without overloading the liver with radioactivity, in contrast to avidin chase.

Algebraic Expressions of Irreducible Bases for the Molecule C60

A general procedure is given for obtaining the algebraic expressions of the irreducible bases for any molecule with icosahedral symmetry from those for the molecule B12H12, which have been obtained using the symmetrized boson representation. As an illustration, concise algebraic expressions of the irreducible bases for the molecules C60 are derived for the most general case; those for any specific case can be derived from them easily without a projection procedure. Copyright 1997 Academic Press. Copyright 1997Academic Press

[Rolipram reversed salbutamol tolerance in guinea pig trachea]

Studies were carried out to examine the role of phosphodiesterase(PDE) III and PDE IV in the development of tachyphylaxis of isolated guinea pig trachea to beta 2 adrenoceptor agonists. Treating trachea with salbutamol(SB) 1 mumol.L-1 for 1 h produced a 5-fold rightward shift of the SB concentration-response curve for the spasmolytic effect against methacholine-induced bronchocontraction and decreased the maximum SB-induced relaxation by 30%, i.e. induced tolerance of airway response of SB in vitro. The PDE IV inhibitor rolipram (Rol, 1 mumol.L-1, IC50), but not the PDE III inhibitor siguazodan (SK&F 94836, 1 mumol.L-1, IC50), reversed the SB tolerance. However, the protein synthesis inhibitor cycloheximide(10 mumol.L-1) did not abolish the SB tolerance. These results indicate that the SB tolerance may be related to increase in PDE IV activity.

Production of human insulin in an E. coli system with Met-Lys-human proinsulin as the expressed precursor

The construction of a gene encoding Lys-human proinsulin, its direct expression in E. coli, and the simple purification procedure are described here. The temperature inducible promotor was employed for induction in a very short time. The expression level could reach 20-30%. After simple downstream processing and only one step of Sephadex G50 purification, 150 mg recombinant Lys-human proinsulin with a purity of up to 90% could be obtained easily from 1 L of high density fermentation medium. The obtained product is in the form of Met-Lys-human proinsulin because of the failure of the bacterial host to remove the initiator methionine residue. The Lys-human proinsulin could be changed into human insulin by trypsin and carboxypeptidase B treatment in later steps. After separation with DEAE-Sephadex A25, human insulin with expected amino acid composition and full native biological activity could be obtained with a yield of 50 mg/L of fermentation medium.

Suppression of the constitutive expression of cytochrome P-450 2C11 by cytokines and interferons in primary cultures of rat hepatocytes: comparison with induction of acute-phase genes and demonstration that CYP2C11 promoter sequences are involved in the suppressive response to interleukins 1 and 6

Hepatic expression of various members of the cytochrome P-450 (CYP) superfamily is suppressed during inflammatory responses. We have shown that the specific expression of P-450 2C11 in male rat liver is suppressed transcriptionally by endotoxin treatment. To investigate the molecular mechanisms underlying this phenomenon, we studied the effects of the inflammatory cytokines interleukin (IL)-1, IL-6, tumor necrosis factor-alpha (TNF), interferon (IFN)-alpha, and IFN-gamma on the expression of P-450 2C11 and the mRNAs of two typical acute-phase protein genes, alpha 1-acid glycoprotein (AGP) and fibrinogen, in primary hepatocyte cultures. IL-1, IL-6, TNF, and IFN-alpha all suppressed P-450 2C11 mRNA, whereas IFN-gamma had no effect. IL-1 and TNF were more effective than IL-6 in the suppression of P-450 2C11 mRNA. Whereas IL-1 and IL-6 effects on P-450 2C11 were accompanied by induction of AGP and fibrinogen mRNAs, IFN-alpha and TNF treatments had no effects on AGP. The suppression of P-450 2C11 and the induction of AGP by IL-1 showed similar time courses. The combination of IL-1 and IL-6 showed additivity in suppression of P-450 2C11, at maximally effective concentrations of cytokines. The effects of IL-1 on P-450 2C11 and AGP expression were blocked by IL-1 receptor antagonist protein. We also studied the effects of IL-1 and IL-6 on the transient expression of chloramphenicol acetyl-transferase reporter gene constructs containing 200 or 1287 base pairs of the 5' flanking region of the CYP2C11 gene, transfected into primary hepatocytes. The chloramphenicol acetyltransferase activities in cells transfected with the 200-base pair construct were reduced to about 33% and 58% of control levels by treatment with IL-1 or IL-6, respectively, suggesting that sequences important for cytokine down-regulation lie within the proximal promoter region of the CYP2C11 gene.

[Rational evaluation of different lymph node dissection]

To evaluate the effect and indication of different lymph node dissection (D1+, D2, D3), we performed radical operations for 371 cases of gastric cancer. The results showed that D1+ or D1 lymph node dissection was enough for gastric cancer of Ia stage, D2 was suitable for Ib stage. For localized or massive type gastric cancer of II + III stage, D3, D2 dissection was better than D1+ dissection. For the gastric cancer of the same type in IV stage, the 5-year survival rate after D3 + D2 dissection was 42.9%, but for the gastric cancer of infiltrative type or diffused growth pattern in II + III stage, the effect was not significantly increased even after the D3, D2 dissection. For the gastric cancer of this type in IV stage, the effect was not improved after the extended lymph node dissection. Extended dissection needn't be performed if there was no lymph node metastasis. D3, D2 dissection was better if there was little lymph node metastasis or the metastasis was limited to 1st group. For those metastasized to 2nd group or the quantity was more, D3 was better than D2, D1+. The effect of D3, D2 dissection was not significantly improved in the extensive metastasis case (more than 10 or to the 3rd group).

[Homoplastic keratomileusis for aphakic eyes with corneal leucoma]

We performed homoplastic keratomileusis on 6 aphakic eyes with central corneal leucoma. The results showed that the post-operative corrected visual acuities were markedly increased to 0.3-0.5 in 3 cases and to 0.1-0.2 in another 3 cases. Since such patients were neither indicated to undergo intraocular lens implantation or penetrating keratoplasty for various reasons nor indicated for epikeratoplasty, homoplastic keratomileusis can be chosen for them.

[Factors of graft failure after chemical corneal injury]

83 cases (97 eyes) of keratoplasty after chemical corneal injury were followed up for a mean 14 months with the results that 21 (21.6%) grafts were transparent and 76 (78.4%) opaque or semitransparent. The success rate depended on the severity of the chemical injury; it was 87.5% for type A corneal scarring and 15.7% for type B. The causes of graft failure were postoperative epithelial erosion (70.7%) and corneal rejection (28.0%). Most patients with epithelial erosion had problems of insufficient tear secretion and tear-film defects. The prevention and management of graft failure were discussed.

Effects of Panax notoginseng saponins on myocardial adenosinetriphosphatase

Effects of total Panax notoginseng saponins (PNS) and Panax notoginseng saponin monomers Rb1 and Rg1 (Rb1, Rg1) on total ATPase and Na(+)-K(+)-exchanging ATPase of guinea pig heart were studied. It was found that PNS inhibited the total myocardial ATPase, but had no significant effect on the myocardial Na(+)-K(+)-exchanging ATPase. The total ATPase was inhibited by Rg1, and more clearly by Rb1. The automaticity and contractility of isolated guinea pig atria were inhibited by Rb1. Rg1 decreased the spontaneous frequency of isolated guinea pig right atrium, but not markedly the contractility of the left atrium. These results demonstrate that Rb1 is the main ingredient in PNS.

[Vitrectomy under temporary keratoprosthesis]

In vitreoretinal disorders complicated by corneal opacity, a temporary keratoprosthesis device is placed into a trephined opening in the cornea to provide a clear stable view which permits the performance of pars plana vitrectomy and immediately following the vitrectomy, the keratoprosthesis is replaced by a corneal graft. Using this technique, we have saved blind eyes with corneal and vitreoretinal disorders in one surgical procedure, being a new approach for rehabilitation of eye sight. Since 1990, the operation has been performed on 10 patients of whom 9 obtained satisfactory results. They were the patients who had been impossible to be saved by other methods and had been abandoned. The patient with the best result had been followed for 15 months and his visual acuity achieved and maintained 0.3. In six cases, the operation was combined with multiple procedures in the vitreous, such as gas fluid exchange, internal drainage of subretinal fluid, injection of silicone oil, etc. to facilitate the reattachment of the complicated retinal detachment.

[An immunohistochemical study of cornea and adjacent bulbar conjunctiva in Mooren's ulcer]

The specimens of the corneal lesions and their adjacent bulbar conjunctivas taken from 14 cases with Mooren's ulcers were studied by immunohistochemical techniques to investigate the expression of HLA-DR antigen and the subgroups of lymphocytes. It is discovered that there is an aberrant expression of HLA-DR antigen in a large amount of keratoconjunctival epithelial cells and stromal keratocytes and simultaneously, the CD4/CD8 ratio is significantly higher than that of the normal control group. The results suggest that the aberrant expression of MHC-II antigen in the resident cells at the peripheral cornea and its adjacent conjunctiva and a raised local TH/TS ratio leading to an excessive autoimmune reactivity be possibly the direct cause of the pathogenesis of the Mooren's ulcer.

[Experimental pharmacokinetic studies of carboplatin intraperitoneal chemotherapy]

High performance liquid chromatography was used to study the performances of carboplatin by intraperitoneal (ip) administration in six dogs. 30 mg/kg carboplatin in 500ml 0.9% sodium chloride was injected ip quickly. Drug levels in the peritoneal fluid and blood of the portal vein and femoral vein were measured at different time intervals. The results showed a high drug concentration in the peritoneal fluid within 240 minutes after large dose and volume of carboplatin administered ip. The peak and mean concentrations of carboplatin in the peritoneal fluid were 139 and 64 times that of blood in the femoral vein, respectively. The peak and mean concentrations of the drug in the portal vein were 13.3 and 6.8 times those in the femoral vein. Intraperitoneal chemotherapy of carboplatin can maintain a stable and persistent high drug level in the peritoneal cavity, portal vein as well as liver. Systemic toxic effects were decreased due to low level of drug in the systemic circulation. These pharmacokinetic properties of carboplatin are of advantage in preventing and treating tumor recurrence in the peritoneal cavity and hepatic metastases.

[Corneal topography of keratoconus]

A computerized video keratoscope (TMS-1) was used to determine the topographic findings of 6 eyes of 4 patients with keratoconus and they were compared with those of 18 normal eyes. The results show that in keratoconus the central corneal refractive power is greater, the difference between the refractive powers of the bilateral central corneas of a case is larger and the inferior cornea is steeper than the superior cornea. The above topographic findings are possibly the characteristics of the corneal topography of keratoconus.