Pharmacokinetics of intravenous chloramphenicol sodium succinate in adult patients with normal renal and hepatic function

The pharmacokinetics of chloramphenicol (CAP) and total chloramphenicol succinate (CAPS) were studied in eight hospitalized adult patients with normal renal and hepatic function receiving intravenous chloramphenicol sodium succinate therapy. The steady-state peak concentrations of CAP (8.4–26.0 g/ml) occurred at an average of 18.0 min (range 5.4–40.2) after cessation of the chloramphenicol sodium succinate infusion. Unhydrolyzed CAPS prodrug, representing 26.0±7.0% of the dose, was recovered unchanged in the urine indicating that the bioavailability of CAP from a dose of intravenous chloramphenicol succinate is not complete. A pharmacokinetic model was developed for simultaneous fitting of CAP and CAPS plasma concentration data. Pharmacokinetic parameters determined by simultaneous fitting were: V, 0.81±0.18 liters/kg; t_1/2, 3.20 ±1.02 hr; CL_B, 3.21±1.27 ml/min/kg for chloramphenicol; and V, 0.38±0.13 liters/kg; t_1/2, 0.57±0.12hr; CL_B, 7.72±1.87 ml/min/kg for total chloramphenicol succinate.Supported in part by Faculty Research Council Grant VF648 from the University of North Carolina.     

Diazepam metabolism in human foetal and adult liver

Summary Diazepam was metabolized by human foetal liver microsomes to N-desmethyldiazepam and N-methyloxazepam as early as the 13th week of gestation. The metabolic activity was lower than that of microsomes from adult human liver. Diazepam was shown mainly to be hydroxylated to N-methyloxazepam at substrate concentrations higher than 0.1 mM. Diazepam levels above 1.0 mM were inhibitory to the overall metabolic reaction. SKF 525-A inhibited diazepam metabolism by foetal liver microsomes at a concentration of 0.1 mM. The addition of diazepam to foetal and adult human liver microsomes resulted in a type II spectral change. Its inhibition by carbon monoxide indicated that biotransformation of diazepam was performed by the cytochrome P-450-linked mono-oxygenase system.     

p16和p15第二外显子HapⅡ位点在成人急性髓性白血病中的突变

目的　探讨p16和p15基因第二外显子HapⅡ位点在成人急性髓性白血病 (AML)中的突变。方法　用甲基敏感和甲基非敏感限制性内切酶切消化基因组DNA后 ,经PCR扩增和琼脂糖电泳研究 3 1例AML中无p16/p15基因第二外显子缺失的患者中HapⅡ位点的突变情况。结果　在 3 1例成人AML样本中 ,p16E2 的 4个HapⅡ位点和p15E2 的 6个HapⅡ位点均未发生突变。结论　本研究提示p16和p15基因第二外显子中因甲基化而引起的CCGG位点的突变在成人AML患者中不是主要失活方式。     

Diagnosis of pneumothorax in critically ill adults

The diagnosis of pneumothorax is established from the patients' history, physical examination and, where possible, by radiological investigations. Adult respiratory distress syndrome, pneumonia, and trauma are important predictors of pneumothorax, as are various practical procedures including mechanical ventilation, central line insertion, and surgical procedures in the thorax, head, and neck and abdomen. Examination should include an inspection of the ventilator observations and chest drainage systems as well as the patient's cardiovascular and respiratory systems.Radiological diagnosis is normally confined to plain frontal radiographs in the critically ill patient, although lateral images and computed tomography are also important. Situations are described where an abnormal lucency or an apparent lung edge may be confused with a pneumothorax. These may arise from outside the thoracic cavity or from lung abnormalities or abdominal viscera inside the chest.     

Impairment in short-term but enhanced long-term synaptic potentiation and ERK activation in adult hippocampal area CA1 following developmental thyroid hormone insufficiency.

Thyroid hormones are critical for the development and maturation of the central nervous system. Insufficiency of thyroid hormones during development impairs performance on tasks of learning and memory that rely upon the hippocampus and impairs synaptic function in young hypothyroid animals. The present study was designed to determine if perturbations in synaptic function persist in adult euthyroid animals exposed developmentally to insufficient levels of hormone. Pre- and postnatal thyroid hormone insufficiency was induced by administration of 3 or 10 ppm propylthiouracil (PTU) to pregnant and lactating dams via the drinking water from gestation day (GD) 6 until postnatal day (PN) 30. This regimen produced a graded level of hormonal insufficiency in the dam and the offspring. Population spike and population excitatory postsynaptic potentials (EPSP) were recorded at the pyramidal cell layer and the stratum radiatum, respectively, in area CA1 of hippocampal slices from adult male offspring. PTU exposure increased baseline synaptic transmission, reduced paired-pulse facilitation, and increased the magnitude of the population spike long-term potentiation (LTP). Phosphorylation of the extracellular signal-regulated kinases (ERK1 and ERK2) was increased as a function of LTP stimulation in slices from PTU-exposed adult animals. On the other hand, no differences in the basal levels of synaptic proteins implicated in synaptic plasticity (total ERK, synapsin, growth-associated protein-43, and neurogranin) were detected. These results reinforce previous findings of persistent changes in synaptic function and, importantly extend these observations to moderate levels of thyroid hormone insufficiency that do not induce significant toxicity to the dams or the offspring. Such alterations in hippocampal synaptic function may contribute to persistent behavioral deficits associated with developmental hypothyroidism.     

Impacts of Informal Caregiver Availability on Long-term Care Expenditures in OECD Countries

Objective. To quantify the effects of informal caregiver availability and public funding on formal long-term care (LTC) expenditures in developed countries.
Data Source/Study Setting. Secondary data were acquired for 15 Organization for Economic Cooperation and Development (OECD) countries from 1970 to 2000.
Study Design. Secondary data analysis, applying fixed- and random-effects models to time-series cross-sectional data. Outcome variables are inpatient or home heath LTC expenditures. Key explanatory variables are measures of the availability of informal caregivers, generosity in public funding for formal LTC, and the proportion of the elderly population in the total population.
Data Collection/Extraction Method. Aggregated macro data were obtained from OECD Health Data, United Nations Demographic Yearbooks, and U.S. Census Bureau International Data Base.
Principal Findings. Most of the 15 OECD countries experienced growth in LTC expenditures over the study period. The availability of a spouse caregiver, measured by male-to-female ratio among the elderly, is associated with a $28,840 (1995 U.S. dollars) annual reduction in formal LTC expenditure per additional elderly male. Availability of an adult child caregiver, measured by female labor force participation and full-time/part-time status shift, is associated with a reduction of $310 to $3,830 in LTC expenditures. These impacts on LTC expenditure vary across countries and across time within a country.
Conclusions. The availability of an informal caregiver, particularly a spouse caregiver, is among the most important factors explaining variation in LTC expenditure growth. Long-term care policies should take into account behavioral responses: decreased public funding in LTC may lead working women to leave the labor force to provide more informal care.     

呼吸机所致大鼠急性肺损伤病理学研究

目的 探讨不同潮气量机械通气大鼠肺组织的病理学变化。方法 32只Wistar大鼠随机分为对照组、小潮气量组、常规潮气量组和大潮气量组，分别在肉眼、光镜和电镜下观察各组大鼠肺组织的病理改变，测定肺湿／干重比值。结果 小潮气量组大鼠肺组织在肉眼、光镜和电镜下观察与对照组比较均无明显差别；常规潮气量组在光镜和电镜下可见肺问质水肿及炎性细胞浸润；大潮气量组肺组织不但在肉眼和光镜下有明显损伤表现，而且在超微结构上也有特殊改变。肺湿／于重比值测定结果显示，大潮气量组和常规潮气量组肺湿／干重比值与对照组和小潮气量组比较差异均有显著性（均P〈0．01）；小潮气量组与对照组比较差异无显著性（P〉0．05）。结论 小潮气量通气对正常肺组织结构无明显影响。     

成人视网膜前体细胞的体外分离培养和鉴定

 【目的】对成人视网膜前体细胞进行体外分离、培养和鉴定。【方法】成人眼球12只，“机械分离联合酶消化法”分离出睫状上皮层的色素性细胞。10ng／mL碱性成纤维细胞生长因子（bFGF）＋10ng／mL表皮生长因子（EGF）的无血清DMEM／F12培养液中培养，并从三方面鉴定其神经干细胞特性：A．免疫荧光染色检测神经干细胞特异性抗原神经巢蛋白Nestin的表达；B．自我更新能力：原代神经球消化传代后，继续培养观察新神经球的形成；C．多向分化潜能：原代细胞培养4～5d，改用含10mL／L胎牛血清的DMEM/F12培养液。继续培养7～10d，分别用抗神经丝蛋白（NF）抗体、抗微管相关蛋白-2（MAP2）抗体、抗胶质纤维酸性蛋白（GFAP）抗体、抗视紫质蛋白抗体、抗β-微管蛋白抗体以及抗无长突细胞特异性抗体作免疫荧光细胞染色。【结果】0．48％±0．08％（1：208）原代细胞在含bFGF＋EGF无血清培养条件下能保持增殖未分化状态。形成神经球样结构，消化传代后90．1％±8．3％的第二代细胞能重新形成新的神经球样结构，具有自我更新能力：原代及传代后的神经球均表达神经干细胞特异性抗原nestin；在含10mL／L胎牛血清的促分化培养液中。细胞分别分化为可表达神经细胞、星形神经胶质细胞和感光细胞等特异性抗原的细胞，表明具有多向分化潜能。【结论】在成人眼睫状体扁平部分离得到具有干细胞特性的视网膜前体细胞，并在体外成功进行培养鉴定。     

黄芪和硫酸锌对肠缺血-再灌注致肺损伤的防治作用

目的：研究黄芪、硫酸锌对肠缺血-再灌注(I／R)过程中肺脂质过氧化变化的影响并探讨其机制。方法：采用夹闭兔肠系膜上动脉及松央再灌注，复制损伤模犁。将动物随机分成4组，观察黄芪、硫酸锌对人、出肺血及肺组织超氧化物歧化酶(SOD)、黄嘌呤氧化酶（XO)、丙二醛(MDA)及肺表面活性物质(PS)含量的影响。结果：肠I／R过程中伴有急性肺损伤，静脉给予黄芪及硫酸锌可使再灌注后XO及MDA含量降低，且可防止SOD和PS减少。结论：黄芪、硫酸锌通过抗脂质过氧化能减轻或住一定程度上防止急性肺损伤的发生和发展。