The pathogenesis of the low pleural fluid pH in esophageal rupture

To determine the possible mechanisms responsible for the low pH pleural effusion associated with esophageal rupture we evaluated the following possibilities: (1) gastric acid reflux, (2) bacterial metabolism, and (3) leukocyte metabolism. Neither elimination of gastric hydrogen ion contribution by distal esophageal ligation nor elimination of bacteria with antibiotics prevented the progressive fall in pleural fluid pH after esophageal rupture. Only elimination of polymorphonuclear leukocytes from the pleural space by rendering animals leukopenic with nitrogen mustard, prevented a low pH effusion after esophageal rupture. It appears that pleural fluid leukocyte metabolism is primarily responsible for the low pH effusion associated with esophageal rupture.     

移动Agent技术的发展

由于缺乏统一的概念框架和应用需求驱动，移动Agent技术的发展受到了阻碍，在研究移动性概念的基础上，分别给出了移动Agent和移动Agent平台的定义，总结了一种移动Agent系统的概念框架，并进一步分析了在此框架下实现移动Agent系统的关联技术，结合当前的互联网应用需求，指出了进一步的研究方向。     

Knowledge of medical history information among proxy respondents for deceased study subjects

Proxy respondents were interviewed for 96 decedents in an occupational cohort. A second respondent was interviewed for 59 decedents. Medical records were reviewed to validate questionnaire information. The percentage of respondents who answered "don't know" (non-response) to questions about medical condition ranged from 5% (cancer and heart disease) to 17% (ulcers). Non-response rates were lowest among spouses, intermediate among children, parents, and siblings, and highest among other relatives and friends. Among 41-55 pairs, depending on the condition, agreement between paired respondents was excellent (kappa > 0.75) for ulcers, cancer, diabetes, and lung disease. A higher percentage of medical records was obtained for decedents with spouse respondents and for decedents with more recent dates of death. Sixty percent or more of the medical records were obtained for patients with cancer (n = 30), heart disease (n = 26), stroke (n = 9), and liver disease (n = 10). The positive predictive value of the proxy respondent information for these conditions was 93, 81, 78, and 60%, respectively.     

North Carolina stroke prevention and treatment facilities survey: rtPA therapy for acute stroke

BACKGROUND and PURPOSE: North Carolina is situated in the "stroke belt" region of the United States, an area of the country with a particularly high incidence of cerebrovascular disease. The North Carolina Stroke Prevention and Treatment Facilities Survey was carried out to determine the availabilities of a variety of stroke prevention and treatment services throughout the state. The purpose of the present study was to determine how widely recombinant tissue-type plasminogen activator (rtPA) has been adopted for the treatment of patients with acute ischemic stroke and to determine the characteristics of the medical facilities in the state offering this therapy. METHODS: A single-page survey was mailed to the medical center directors of each inpatient medical facility in North Carolina. Data collected included questions related to the availability of selected basic and advanced diagnostic tests and procedures, stroke prevention and treatment programs and services (community stroke awareness program, acute stroke identification program, acute stroke team, stroke rtPA protocol, stroke care map, neurologist), and facilities (Stroke Acute Care Unit or equivalent). RESULTS: Responses were obtained from all 125 inpatient medical facilities in North Carolina. rtPA stroke protocols were adopted in 54 facilities located in 46 of the state's 100 counties. Seventy-four percent of the state's population resides in counties with hospitals providing rtPA treatment. Compared with facilities not offering rtPA, those with rtPA protocols more commonly sponsored stroke community awareness programs (41% versus 17%, P=0.003) and more frequently had an organized stroke team (31% versus 8%, P=0. 001), used stroke care maps (56% versus 17%, P<0.001), had rapid stroke identification programs (33% versus 6%, P<0.001), or had a Stroke Acute Care Unit or its equivalent (33% versus 7%, P<0.001). Neurologists were available in 78% of the facilities offering rtPA compared with 38% in facilities without rtPA protocols (P<0.001). CONCLUSIONS: These data show that this new therapy for ischemic stroke is potentially available to a high proportion of the state's citizens based on their county of residence. However, other services that may improve outcomes and reduce stroke-related costs (eg, stroke teams, stroke units, care maps) are not being widely used, even in centers providing treatment with rtPA. The simple methodology used in this study is potentially applicable in other states and permits targeting of selected centers for development of stroke treatment capabilities.     

Comparison of bax, waf1, and IMP dehydrogenase regulation in response to wild-type p53 expression under normal growth conditions

Recently, we demonstrated that downregulation of inosine-5'-monophosphate dehydrogenase (IMPD; IMP:NAD oxidoreductase, EC 1.2.1.14), the rate-limiting enzyme for guanine nucleotide biosynthesis, is required for p53-dependent growth suppression. These studies were performed with cell lines derived from immortal, nontumorigenic fibroblasts that express wild-type p53 conditionally by virtue of a metal-responsive promoter. Here, the p53-dependent properties of the original "p53-inducible" fibroblasts are presented in detail and compared to related properties of epithelial cells that also express wild-type p53 conditionally, but by virtue of a temperature-responsive promoter. Both types of p53-inducible cells were designed to approximate normal physiologic relationships between the host cell and the regulated p53 protein. Together, they were used to investigate expression relationships between IMPD and other p53-responsive genes proposed as mediators of p53-dependent growth suppression. In both types of cells, IMPD activity, protein, and mRNA were consistently coordinately reduced in response to p53 expression. In contrast, mRNAs for waf1, bax, and mdm2 showed disparate patterns of expression, being induced in one conditional cell type, but not the other. This distinction in regulation pattern suggests that under normal growth conditions, unlike IMPD downregulation, bax and waf1 induction is not a rate-determining event for p53-dependent growth suppression.     

Acute suppurative thyroiditis and aggressive malignant thyroid tumors: differences in clinical presentation

The FDA has issued proposed regulations to require that manufacturer's evaluate the "steam sterilizability" of parenteral products. There are many different ways to assess sterilizability. Within a company, it is helpful to standardize the methodology used to determine whether the product should be terminally sterilized. The following is one approach to determining product sterilizability. This approach is also depicted in a flow chart (Figure 4).