Mouse spleen lymphoblasts generated in vitro. Their replication and differentiation in vitro

Mouse spleen lymphoblasts induced with lipopolysaccharide and fetal calf serum were obtained in high yield and purity in their first proliferative cell cycle by floatation in dense bovine plasma albumin columns (3). The blasts were maintained in vitro for 3 more days. The cultures were examined in bulk on each day, and in addition, those cells in S phase initially were tagged with [(3)H]thymidine and followed continuously in vitro. Grain count dilution data indicated that most blasts divided but twice over a 2- to 3-day interval in vitro. [(3)H]Thymidine pulse radiolabeling and flow microfluorometry suggested that at least 50-70 percent of the proliferating blasts withdrew from proliferative activity after 2-3 days of culture. Morphologic studies demonstrated that lymphoblasts persisted as such for 1-2 days in vitro and then matured into typical plasma cells. Many of the blastprogeny had small nuclei and considerable basophilic cytoplasm on Giemsa-stained cell smears; abundant rough endoplasmic reticulum by electron microscopy; and readily detectable cytoplasmic Ig by immunocytochemistry. Reversion of blasts to small lymphocytes could not be detected; however, some blasts persisted even after 3 days of culture. The viability of the cultured lymphoblast was followed by initially tagging the cells with [(3)H]thymidine as well as several other techniques. Little cell death was documented during the first day of culture. The number of labeled progeny increased twofold whereas the grain count halved. But 40- 50 percent of the cell-associated label was lost during each of the second and third days, and fewer labeled progeny than predicted by grain count dilution were identified. The culture medium could not be implicated in this loss of lymphoblast progeny, and we suggest that the maturation of the lymphoblast to a short-lived plasma cell was responsible. Therefore mitogen-stimulated B blasts seem to mature into typical plasma cells after just two cycles of cell division. The plasma cells resemble those produced in situ during an immune response in their cytologic features, withdrawal from active proliferative activity, and short life-span.     

Erythema multiforme, Stevens–Johnson syndrome and toxic epidermal necrolysis in northeastern Malaysia

Background Previous studies have reported that drugs and infections are common causes of erythema multiforme (EM) and Stevens–Johnson syndrome (SJS). Toxic epidermal necrolysis (TEN) is mainly related to drugs. No study has been conducted in Kelantan, the northeastern state of Malaysia, to assess these cutaneous reactions. Methods A retrospective study of all hospitalized cases of EM, SJS, and TEN was conducted covering an 8-year period from 1987 to 1994. Results There were four cases (13.8%) of EM, 22 cases (75.9%) of SJS, and three cases (10.3%) of TEN. Drugs as a definitive cause was observed in one case (25%) of EM, 12 cases (54.5%) of SJS, and two cases (66.7%) of TEN. Drugs as a probable cause was observed in seven cases (31.8%) of SJS and one case (33.3%) of TEN. The male to female ratio was equal in EM and SJS. Antiepileptics were the commonest culprits, followed by antibiotics. One patient died of SJS and one patient died of TEN, giving mortality rates of 4.5% and 33.5% respectively. Fever was noted in 18 patients (62.1%). Leukocytosis was noted in 10 patients (34.5%), and nine patients (31.0%) had elevated liver transaminase enzymes. No significant correlation was noted between these biochemical changes and cutaneous eruption. Secondary infections were observed in 11 patients (37.9%): Staphylococcus aureus was the commonest isolated organism. Conclusions This study shows that drugs remain the commonest culprit in SJS and TEN. Despite adequate treatment, the mortality rate remains high, especially in TEN. These findings are similar to those of other reported studies.     

盐步医院2008年细菌耐药性分析

目的了解本院2008年临床分离出的细菌对各类抗菌药物的耐药性,为临床合理应用抗生素提供依据。方法采用法国生物梅里埃ATB-Expression细菌鉴定仪进行细菌鉴定及药敏试验,应用Whonet5.4软件统计耐药率。结果临床分离274株细菌中革兰阳性球菌83株(30.5%),革兰阴性杆菌191株(69.5%);金黄色葡萄球菌和凝固酶阴性葡萄球菌中耐甲氧西林分别占63.2%和80.8%,未发现万古霉素耐药菌株。大肠埃希菌和肺炎克雷伯菌中产ESBLs菌株检出率分别为44.6%和35.7%,各种肠杆菌科细菌和铜绿假单胞菌对亚胺培南敏感,耐药率1.4%～5.9%。结论通过监测临床致病菌的分布特点和耐药性变迁,对指导临床合理使用抗生素,控制医院感染和细菌耐药性发展有重要意义。     

Risk perception and impact of Severe Acute Respiratory Syndrome (SARS) on work and personal lives of healthcare workers in Singapore: what can we learn?

INTRODUCTION: Healthcare workers (HCWs) were at the frontline during the battle against Severe Acute Respiratory Syndrome (SARS). Understanding their fears and anxieties may hold lessons for handling future outbreaks, including acts of bioterrorism. METHOD: We measured risk perception and impact on personal and work life of 15,025 HCWs from 9 major healthcare institutions during the SARS epidemic in Singapore using a self-administered questionnaire and Impact of Events Scale and analyzed the results with bivariate and multivariate statistics. RESULTS: From 10,511 valid questionnaires (70% response), we found that although the majority (76%) perceived a great personal risk of falling ill with SARS, they (69.5%) also accepted the risk as part of their job. Clinical staff (doctors and nurses), staff in daily contact with SARS patients, and staff from SARS-affected institutions expressed significantly higher levels of anxiety. More than half reported increased work stress (56%) and work load (53%). Many experienced social stigmatization (49%) and ostracism by family members (31%), but most (77%) felt appreciated by society. Most felt that the personal protective measures implemented were effective (96%) and that the institutional policies and protocols were clear (93%) and timely (90%). CONCLUSION: During epidemics, healthcare institutions have a duty to protect HCWs and help them cope with their personal fears and the very stressful work situation. Singapore's experience shows that simple protective measures based on sound epidemiological principles, when implemented in a timely manner, go a long way to reassure HCWs.     

Physician attitudes toward end-stage heart failure: a national survey

Background

Despite recent improvements in medical therapies, heart failure remains a prevalent condition that places significant burdens on providers, patients, and families. However, there is a paucity of data published describing physician beliefs about heart failure management, especially in its advanced stages.

Methods

In order to better understand physician decision-making in end-stage heart failure, we used a stratified random sampling of physicians obtained from the Master File of the American Medical Association to survey cardiologists (n = 600), geriatricians (n = 250), and internists/family practitioners (n = 600).

Results

Response rate was 59.6% (highest among geriatricians). The vast majority (>90%) of respondents cited similarities between the clinical trajectory of end-stage heart failure and lung cancer or chronic obstructive pulmonary disease; however, only 15.7% stated that they could predict death at 6 months “most of the time” or “always.” Inpatient volume was a predictor of confidence in predicting mortality (odds ratio = 1.38, 95% confidence interval, 1.36-1.40). Less than one quarter of respondents formally measure quality of life. The experience with deactivation of implantable cardioverter defibrillators was limited: 59.8% of cardiologists, 88.0% of geriatricians, and 95.1% of internal medicine/family practice physicians have had 2 or fewer conversations with patients and families about this option.

Conclusions

Significant gaps in knowledge about and experience with end-stage heart failure exist among a large proportion of physicians. The growing prevalence and highly symptomatic nature of heart failure highlight the need to further evaluate and improve the way in which care is delivered to patients dying from the disease.     

Electrical Performance of Polymer-Insulated Rail Brackets of DC Transit Subjected to Lightning Induced Overvoltage

The fourth rail transit is an interesting topic to be shared and accessed by the community within that area of expertise. Several ongoing works are currently being conducted especially in the aspects of system technical performances including the rail bracket component and the sensitivity analyses on the various rail designs. Furthermore, the lightning surge study on railway electrification is significant due to the fact that only a handful of publications are available in this regard, especially on the fourth rail transit. For this reason, this paper presents a study on the electrical performance of a fourth rail Direct Current (DC) urban transit affected by an indirect lightning strike. The indirect lightning strike was modelled by means of the Rusck model and the sum of two Heidler functions. The simulations were carried out using the EMTP-RV software which included the performance comparison of polymer-insulated rail brackets, namely the Cast Epoxy (CE), the Cycloaliphatic Epoxy A (CEA), and the Glass Reinforced Plastic (GRP) together with the station arresters when subjected by 30 kA (5/80 µs) and 90 kA (9/200 µs) lightning currents. The results obtained demonstrated that the GRP material has been able to slightly lower its induced overvoltage as compared to other materials, especially for the case of 90 kA (9/200 µs), and thus serves better coordination with the station arresters. This improvement has also reflected on the recorded residual voltage and energy absorption capacity of the arrester, respectively.