Typing for HLA Class I Gene Products Using Plasma as Source

Soluble HLA class I proteins have been found in serum or plasma of healthy and diseased individuals. Here we present evidence that these molecules can be readily used for determination of the HLA type by biochemical methods. Immunoprecipitation of the soluble class I gene products using monomorphic monoclonal antibodies coated to immunobeads and one-dimensional isoelectric focusing followed by immunoblotting represents a feasible and reproducible technique for typing. Analysis of these gene products in families (n = 12, with a total of 62 individuals) as well as in the population (n = 82) showed that all serologically defined antigens tested to date were present in plasma. A reference chart established primarily for the membrane-bound antigens could also be used for the soluble ones.     

Impaired Glucose Metabolism and the Exaggerated Blood Pressure Response to Exercise Treadmill Testing in Normotensive Patients

The authors aimed to investigate the association between glucose metabolism measures and the exaggerated blood pressure response (EXBPR) to exercise testing in normotensive nondiabetic patients. One hundred and forty-two consecutive patients underwent office blood pressure (BP) measurements, 24-hour BP monitoring, echocardiography, and treadmill exercise test according to the Bruce protocol. The population was divided into 2 groups according to EXBPR at a submaximal workload level. Furthermore, blood samples were obtained for fasting glucose (FG), fasting insulin (FI), and lipid profile assessment. Measures of insulin resistance (homeostasis model assessment of insulin resistance [HOMA-IR], quantitative insulin sensitivity check index [QUICKI], and McAuley index) were also estimated, and a standardized oral glucose tolerance test was performed to evaluate glucose levels at 120 minutes (G120). Patients with EXBPR (n=40; 27 men) compared with those without EXBPR (n=102; 66 men) were older by 4±6 years (P<.001). FG, FI, G120, HOMA-IR, QUICKI, and McAuley index differed in patients with EXBPR compared with those without EXBPR (P<.001 for all). Logistic multivariable regression models revealed that the studied glucose metabolism measures, duration of exercise, and 24-hour systolic BP remained determinants of EXBPR (P<.05 for all) after adjustment. Impaired glucose measures are significant determinants of EXBPR to exercise testing in normotensive nondiabetic patients, suggesting that impaired glucose metabolism may contribute to adverse cardiovascular prognosis including new-onset hypertension.     

Survival among children with medulloblastoma in Greece: gains from transition to chemotherapy and socio-economic differentials.

The objective of this study was to quantify improvements in survival due to chemotherapy among children with medulloblastoma treated during the last three decades at a university unit in Greece, compare these gains with figures derived from a specialized unit in the United States and explore the role of extrinsic factors affecting survival. The records of all children with medulloblastoma (n=50) treated at the University Childhood Oncology Unit in Athens, Greece during the period 1973-2003 were reviewed. The role on survival of socio-demographic factors was studied by modeling the data through Cox's proportional-hazards regression, controlling for the mode of treatment (chemotherapy, yes vs. no), whereas survival of children with medulloblastoma treated in Greece was compared with that of 76 children treated in a specialized center in the United States during a respective period. After adjustment for demographic factors, children with medulloblastoma who received adjuvant therapy in Greece had an approximately four times higher instantaneous rate of remaining alive than those who did not (P=0.05). The 5-year survival of children with medulloblastoma treated at specialized medical centers in Greece and the United States was 66 and 63%, respectively. Despite the comparable figure with that of an acceptable standard, however, there was a suggestion (P=0.07) that a rural place of residence in Greece is a poor prognostic indicator. Assuming inherently similar age of occurrence in urban and rural areas, children from rural areas in this study had a more advanced age at diagnosis than those residing in urban Greece (mean age: 7.9 vs. 6.6 years) with a 5-year survival of 57 and 73%, respectively. As expected, incorporation of adjuvant chemotherapy in the treatment of Greek children with medulloblastoma has yielded remarkable improvement in 5-year survival, comparable to that of technologically advanced countries. On the contrary, children residing in rural areas of the country seem to enjoy less favorable prognosis, possibly owing to delays in diagnosis or limited access to optimal treatment facilities.     

Disposition of valproic acid in the rat: dose-dependent metabolism, distribution, enterohepatic recirculation and choleretic effect.

A specific gas chromatographic assay has been developed for measurement of valproic acid (VPA) and its major conjugated metabolites. In rats given single intravenous doses, the decline in blood concentration of VPA was dose-dependent and followed first-order kinetics only at the lowest dose. The time required for the maximum concentration of VPA, after completion of the brief distribution phase, to decline by 50% was 11.7, 41 and 125 min at doses of 15, 150 and 600 mg of NaVPA per kg, respectively. A secondary increase in drug concentration, abolished by exteriorization of the bile, was observed in all intact rats with all doses. Some 45 to 55% of the dose appeared in the bile in 5 hr as VPA glucuronide. Urinary excretion of VPA glucuronide in intact animals accounted for 23 and 51% of the 15 and 150 mg/kg doses, respectively. Tissue distribution studies in rats sacrificed 20 and 90 min after dosage with [14C] NaVPA (150 mg/kg) showed that the drug concentration was highest in blood, moderate in liver, kidney, heart and lung and low in brain, fat, testis and skeletal muscle. During this interval the drug concentration declined in all tissues, whereas the total conjugated metabolites in the small intestine increased from 7 to 28% of the administered dose. The large intestine contained 30 times as much free drug as conjugate. Reabsorption of free VPA, released by hydrolysis of conjugate in the large bowel, accounted for the secondary rise in concentration of VPA observed in blood after single doses. The major urinary metabolites, VPA-glucuronide and 2-n-propylgutaric acid, were identified by gas chromatography/chemical ionization mass spectrometry. Sodium VPA caused a dose-dependent stimulation of bile flow, the magnitude and duration of which closely followed the blood concentration of VPA.     

Adrenal function in non-septic long-stay critically ill patients: evaluation with the low-dose (1 micro g) corticotropin stimulation test

OBJECTIVE: To investigate the adrenal function in non-septic, long-stay critically ill patients. DESIGN: Prospective, consecutive study. SETTING: General intensive care unit in a university hospital. PATIENTS: Forty-three non-septic patients with protracted critical illness. INTERVENTIONS: A morning blood sample was first obtained to measure baseline plasma cortisol. Subsequently, 1 micro g of corticotropin (ACTH, Synacthene) was injected intravenously and 30 min later a second blood sample was drawn to determine stimulated plasma cortisol. Patients having a stimulated cortisol level of at least 18 micro g/dl were defined as responders. In 36 patients, morning interleukin-6 (IL-6) was also measured. MEASUREMENTS AND RESULTS: Baseline and stimulated plasma cortisol were 16.8+/-4.1 micro g/dl and 21.2+/-5.1 micro g/dl, respectively. Interleukin-6 was high (median 39.3 pg/ml, interquartile range 24.9-86.6 pg/ml) and correlated negatively with stimulated plasma cortisol (r=-0.40, p<0.05). Of the 43 patients studied, 31 patients (72%) were responders and 12 patients (28%) were non-responders to the ACTH stimulation test. Overall, 18 patients died and 25 patients survived to hospital discharge. Non-responders had significantly higher IL-6 levels compared to responders (106+/-73 versus 48+/-42 pg/ml, p<0.05), whereas mortality rate was comparable in the two groups (50% versus 38%, p=0.74). CONCLUSIONS: Circulating plasma IL-6 levels are high during protracted critical illness, and are partially responsible for the relative adrenal insufficiency found in a subset of severely ill patients.     

Impact of passive humidification on clinical outcomes of mechanically ventilated patients: a meta-analysis of randomized controlled trials

OBJECTIVE: Previous meta-analyses reported advantages of passive (i.e., heat and moisture exchangers, or HMEs) compared with active (i.e., heated humidifiers, or HHs) humidifiers in reducing the incidence of ventilator-associated pneumonia, but they did not examine the effect of these devices on mortality, length of intensive care unit stay, and duration of mechanical ventilation. In addition, relevant data were recently published. DESIGN: Meta-analysis of randomized controlled trials comparing HMEs with HHs for the management of mechanically ventilated patients to determine the impact of these devices on clinical outcomes of such patients. METHODS: We searched PubMed and the Cochrane Central Register of Controlled Trials as well as reference lists from publications, with no language restrictions. We estimated pooled odds ratios (ORs) and 95% confidence intervals (CIs), using a random effects model. RESULTS: Thirteen randomized controlled trials, studying 2,580 patients, were included. There was no difference in incidence of ventilator-associated pneumonia among patients managed with HMEs and HHs (OR 0.85, 95% CI 0.62-1.16). There was no difference between the compared groups regarding mortality (OR 0.98, 95% CI 0.80-1.20), length of intensive care unit stay (weighted mean differences, -0.68 days, 95% CI -3.65 to 2.30), duration of mechanical ventilation (weighted mean differences, 0.11 days, 95% CI -0.90 to 1.12), or episodes of airway occlusion (OR 2.26, 95% CI 0.55-9.28). HMEs were cheaper than HHs in each of the randomized controlled trials. CONCLUSION: The available evidence does not support the preferential performance of either passive or active humidifiers in mechanical ventilation patients in terms of ventilator-associated pneumonia incidence, mortality, or morbidity.