A study of the relationship between ambient lead and blood lead among lead battery workers

 Objective: To examine the relationship between ambient lead levels and blood lead levels and to explore the modifiers of the relationship between ambient lead and blood lead. Method: A cross-sectional study was conducted in two lead battery factories. Blood lead level and ambient lead concentration were measured for each participant concurrently. A structured questionnaire was administered to collect sociodemographic characteristics and occupational history. Design: Biological and personal environmental measurements of 219 lead-exposed workers were analyzed by both simple and multiple linear regression. A regression model was selected for interpretation. Results: A high correlation (r=0.62) between ambient lead (PbA) and blood lead (PbB) was observed. In addition, numerous factors, including age, sex, alcohol consumption, personal hygiene practice and type of lead exposure, were also found to influence blood lead levels. Although PbB was highly correlated with PbA, blood lead level may not be effectively lowered by reducing ambient lead level. Based on the regression coefficients, improvement of hygienic practice was more effective at lowering PbB than reducing ambient lead level. Good hygienic practice may be the preferential way to reduce lead exposure in current conditions. Conclusion: Education of correct work practice may be more important than engineering control in the developing countries to lower blood lead levels in lead battery factories. Received: 28 May 1996/Accepted: 30 August 1996     

Photoinactivation of bladder tumor cells by methylene blue: study of a variety of tumor and normal cells

Human bladder cancer cell lines, J82, Yen-87, Shen-87 and Zoa-88, and murine bladder cancer cell lines, MBT-2 and M1660, were used as target cells for dye-sensitized photoinactivation study in using methylene blue. Normal fibroblast cells, FB-1 and FB8490, were used as control group. The cytoplasmic activity of lactic dehydrogenase, soft agar clonogenic assay, and in vivo tumor growth, survival rate and tumor taking rate with or without photoinactivation were monitored and compared between different cell lines. Efficacy of photoinactivation was time-related and more than 90 per cent of cytotoxicity could be obtained within 60 minutes of illumination. The plateau of cytotoxicity curve could be achieved after staining for 30 minutes by methylene blue under the same illumination time. Normal fibroblasts had the same features with cancer cells. Photoinactivation of tumor cells showed significant inhibition of tumor growth and tumor taking rate in experimental animals. Survival rate was also significantly prolonged in the animals with tumor cells receiving photoinactivation. These results suggest that methylene blue-sensitized photoinactivation may be useful as an adjuvant photochemotherapy for superficial bladder cancer.     

Features of head injury in a developing country--Taiwan (1977-1987)

Certain features of head-injured patients admitted to the Chang Gung Memorial Hospital in Taiwan during the period 1977 to 1987 were reviewed. The most common causes of injury were motorcycle accidents (56.3%) and street accidents with pedestrian injury (29.47%). The age groups with the greatest incidence of injury were aged 16-20 years, 21-25 years, and 25-30 years. The pedestrian group involving the highest incidence of injury was less than 10 years of age. Overall mortality was 17.26%. The injured pedestrian group had the highest mortality (19.1%). Initial clinical assessment was recorded using the Glasgow Coma Scale. Head-injured patients with a GCS less than 8 had a mortality in the injured pedestrian group of 46%, whereas the mortality rate in the motorcycle accident group was 41%. Additional features studied were time of occurrence of injury and pattern of injury. Information gathered from this study would suggest the need to establish a Head Injury Prevention Program in Taiwan. This of course implies major cooperation among the providers of health care delivery, the medical profession, legislators, and the government at all levels.     

Primary cutaneous rhabdomyosarcoma

We report an unusual case of primary cutaneous embryonal rhabdomyosarcoma presenting as a solitary skin lesion on the anterior chest of a 20-month-old child. The tumor was characterized by small, round to oval, poorly differentiated cells. Immunohistochemically, the tumor was negative for NSE, S-100 protein, LCA, and keratin but positive for muscle-specific actin, myoglobin, desmin, and vimentin, thus indicating the presence of myogenous differentiation. Ultrastructural analysis demonstrated thick and thin filaments. Special studies showed no evidence of a primary rhabdomyosarcoma in the patient at a more typical location, nor was there any evidence of metastases.     

Repeat hepatic resections for colorectal metastases

We identified 106 patients who had undergone complete resection of isolated colorectal hepatic metastases. Nine of these patients subsequently underwent repeat liver resections for isolated hepatic recurrences. The median follow-up for these patients was 21 months. One postoperative death was related to the second hepatectomy. At the time of last follow-up, five patients were alive and free of recurrent disease at 9, 19, 31, 50, and 67 months after their second hepatic resection. The remaining three patients were alive, but disease had recurred 11 months after resection in the first patient, 12 months after resection in the second, and 18 months after resection in the third. Among these three patients, two had solitary pulmonary nodules, which were resected, and one had unresectable liver disease. Our experience and a review of the literature suggest that repeat hepatic resection for isolated colorectal metastases can result in long-term survival in selected patients.     

Detection of RAS mutations in archival testicular germ cell tumors by polymerase chain reaction and oligonucleotide hybridization.

Preliminary studies of RAS mutational activation in human testicular germ cell neoplasms have yielded conflicting results. Whereas two studies of clinical material revealed a significant incidence of N- and KRAS mutations, two studies of a variety of germ cell lines failed to document RAS mutations. To clarify the incidence of RAS mutations in these tumors, we studied archival paraffin-embedded, formalin-fixed orchiectomy specimens from 25 nonseminomas (NSGCT), 18 seminomas (SEM), and one Leydig cell tumor. For 14 of the 44 neoplasms, DNA was also available from nonmalignant testis adjacent to the tumor. Six age-matched patients had testes removed because of nonmalignant disease and were studied as controls. Polymerase chain reaction (PCR) amplified the K-, N-, and HRAS 12, 13, and 61 codons of these specimens, and mutations were detected with mutation-specific oligonucleotide probe hybridization of Southern and slot blots. Four mutations were found in KRAS 12 (4/44;[9.1%]). One seminoma [1/18(5.6%)] contained the mutation GGT(GLY)----CGT(ARG), and three NSGCT [3/25(12%)] were found to have GGT(GLY)----GAT(ASP) mutations. One of the NSGCT mutations was detected in adjacent nonmalignant tissue, but the corresponding tumor did not contain any detectable mutation. No mutations were detected at KRAS 13 or 61, in NRAS or HRAS 12, 13, or 61, or in the control normal testes. PCR, slot blots, and hybridizations were performed twice by two separate investigators for confirmation of results. PCR-generated mutation-specific positive controls were created for all possible RAS mutations, and these along with wild-type DNA controls were integral to interpretation of the oligonucleotide mismatch hybridization assay. By using positive and negative controls, we have detected a relatively low incidence of RAS mutations in archival human testicular germ cell tumors.     

育龄妇女月经周期中心血管功能的变化

本研究采用先进的三维超声成像技术及多普勒技术对正常育龄妇女月经周期中心血管功能进行研究。结果：月经周期中ＨＲ、ＢＰ无变化；血清Ｅ２是周期性变化，排卵前达高峰。ＳＶ、ＣＯ、ＥＦ在排卵前期升高达峰值，显著高于月经期和黄体期；ＳＶＲ排卵前期最低，而Ｖｅｄ、Ｖｅｓ无变化。Ｖｍａｘ、Ａ、Ｅ在内源性Ｅ２高峰时明显加快，而Ｅ／Ａ比值无明显变化。结果提示：月经周期中随内源性Ｅ２的周期性变化，心脏功能也发生周期性变化。Ｅ２高峰时，心输出量、心搏量和射血分数达最高。外周阻力最低，心脏内血流速度加快。     

《医院感染控制多媒体教学》软件的设计与应用

为加强医院感染控制，开展医院感染控制继续教育，本介绍了医院感染控制多媒体软件的设计与应用，为有效预防和控制医院感染，促进医院感染控制的进展，把感染管理工作推上新的台阶提供参考。     

Cellular interactions in effector cell generation and tumor regression mediated by anti-CD3/interleukin 2-activated tumor-draining lymph node cells.

Previous studies have demonstrated that progressive growth of the weakly immunogenic MCA 106 murine sarcoma stimulated, in the draining lymph nodes, the production of tumor-sensitized but not fully functional preeffector lymphocytes. These lymphocytes could develop into specific immune effector cells after sequential in vitro activation with anti-CD3 monoclonal antibody and interleukin 2 (IL-2). In this study, we analyzed cellular requirements for in vivo sensitization of preeffector cells, for generation of immune effector cells by the method of anti-CD3/IL-2 activation, and for adoptive immunotherapy mediated by activated cells. By selective depletion of T-cell subsets in vivo, we found that tumor regression after systemic adoptive immunotherapy required the collaboration of activated CD4+ and CD8+ cells. It was further demonstrated that CD8+ immune cells alone could mediate antitumor effects if exogenous IL-2 was provided in vivo. These results suggest that CD8+ cells served as immediate effector cells, whereas CD4+ immune cells provided a helper function via the secretion of IL-2. During in vitro anti-CD3/IL-2 activation, generation of effector cells depended on the collaborative interaction between previously sensitized CD4+ and CD8+ preeffector cells. At the stage of in vitro activation, the addition of IL-2 could not substitute the function of CD4+ cells. We next examined whether the sensitization of preeffector cells in the draining lymph nodes required cellular interactions between CD4+ and CD8+ T-cells. By in vivo depletion of T-cell subsets during tumor growth, we found that CD4+ cells were sensitized independently of CD8+ cells. More interestingly, in vivo sensitization of CD8+ preeffector cells also occurred independently in the absence of a CD4+ helper cell response. The lack of T-cell-T-cell interactions in vivo may explain the failure of effector cell generation during progressive tumor growth. Taken together, these results demonstrate that the anti-CD3/IL-2 activation defines an immune response distinct from many previously described mechanisms of antitumor immune responses.     

Comparison of polychlorinated dibenzodioxin levels with hepatic mixed-function oxidase induction in great blue herons

As part of the Canadian Wildlife Service monitoring of great blue herons in British Columbia, eggs were collected from three colonies with low, intermediate, and high levels of PCDD and PCDF contamination: Nicomekl, Vancouver, and Crofton, respectively. One egg from each nest was used for chemical analysis by GC-MS; the others were hatched. Liver microsomes were prepared from the heron chicks and used for determination of cytochrome P-450-dependent activities. No erythromycin N-demethylase activity was found in any sample. Ethoxyresorufin O-dealkylase activity in the Nicomekl group was similar to that in pigeons, a control altricial species. The ethoxyresorufin activity in the herons from the Crofton colony was 2.6-fold higher than in the Nicomekl group. The Vancouver colony was intermediate. No difference among the three heron colonies was found in pentoxyresorufin O-dealkylase activity, although levels were 20-33 times that in the pigeon. Chemical analysis was carried out on paired heron eggs. Vancouver and Crofton eggs contained 13.5 and 21 times the levels of 2,3,7,8-TCDD compared to the Nicomekl group. The Crofton eggs contained higher levels of several other contaminants also. A highly significant correlation (p less than .001) was found between ethoxyresorufin O-dealkylase and 2,3,7,8-TCDD concentrations. The correlation coefficient did not change when ethoxyresorufin O-dealkylase was compared to total chemical contamination using several toxic equivalency factors. Multiple regression analysis resulted in only one predictor variable for ethoxyresorufin O-dealkylase: 2,3,7,8-TCDD.