抗血管生成因子Angiostatin与Endostatin作用下肿瘤血管生成的二维数值模拟

目的数值模拟抗血管生成因子Angiostatin和Endostatin对肿瘤血管生成的影响。方法建立肿瘤内外血管生成的二维离散数学模型。模型耦合两种抗血管生成因子Angiostatin和Endostatin的抑制效应,数值模拟在促血管生成因子诱导下肿瘤微血管网生成,讨论血管生成抑制因子的影响。结果抗血管生成因子Angiostatin对肿瘤内外血管网络生成的速度和成熟度有抑制作用。抗血管生成因子Angiostatin和Endostatin耦合作用时,在肿瘤血管生成的早期有明显的抑制效应;在肿瘤血管生成的中后期,它们可以降低肿瘤血管化程度。结论本文模型能够较好的模拟抗血管生成因子Angiostatin和Endostatin对内皮细胞迁移和增殖的抑制作用。     

CSF monoamine metabolites in chronic pain

Metabolites of selected neurotransmitters (5-HIAA, HVA and DOPAC) and beta-endorphin were measured in the CSF of 39 chronic pain patients and compared to controls. Twelve of the pain patients also fulfilled criteria for major depression. The concentration of 5-HIAA was increased in female but not male pain patients; there was no significant difference in the CSF concentrations of HVA and DOPAC. The presence of depression did not influence the concentrations of neurotransmitters. No correlation was found between the concentrations of monoamine metabolites and beta-endorphin. However, there was a positive correlation between 5-HIAA and HVA in controls and chronic pain patients without depression but not in depressed patients. It is concluded: chronic pain states are associated with elevation of CSF 5-HIAA in female patients; depression abolishes a positive correlation between 5-HIAA and HVA.     

Intratympanic steroid therapy for refractory sudden sensory hearing loss: a 12-year experience with the Silverstein catheter

Background: Sudden sensorineural hearing loss (SSNHL) is commonly encountered in clinical practice.

Aim/Objective: Determine if local administration of corticosteroids to the inner ear can improve hearing and speech intelligibility after the failure of conventional treatment for SSNHL loss when administered for 10 days after the onset of the hearing loss in a large cohort of 77 patients.

Materials and methods: A Silverstein MicroWick? was placed under local anesthesia and endoscopic control in the round window niche, allowing self-administration of methylprednisolone twice daily for four weeks.

Results: An improvement of the pure tone average was shown in 31% of patients. Speech intelligibility improved significantly in 55% of the total cohort and in 34% of the population with a stable pure tone average. Among the 77 patients, 22% used a hearing aid. Only 14% of the patients were hearing-aid users in the group with an improvement in speech intelligibility as opposed to 31% in the failure group.

Conclusion and significance: Local administration of steroids to the inner ear through the round window route improves hearing and speech intelligibility in patients after failure of conventional therapy. The use of a hearing aid was reduced by 50% when speech intelligibility was improved.     

Lowering of glucose in critical care: a randomized pilot trial

BACKGROUND: Similar to cardiac surgery patients, medical-surgical critically ill patients may benefit from intensive insulin therapy. The objectives of this pilot trial were to evaluate the feasibility of a randomized trial of intensive insulin therapy with respect to (a) achieving target glucose values in the 2 ranges of 5 to 7 and 8 to 10 mmol/L and (b) uncovering problems with the protocol in anticipation of a larger trial. SETTING: The trial was conducted in a 15-bed medical-surgical university-affiliated intensive care unit (ICU). METHODS: We included patients older than 18 years, expected to be in ICU for more than 72 hours, with a glucose value of more than 10 mmol/L within 48 hours of ICU admission. Exclusion criteria were diabetic ketoacidosis, severe hepatic failure or hepatic resection, pancreatitis, glucose of less than 2.2 mmol/L on admission to hospital, insulin infusion on admission to ICU, planned withdrawal of life support, and inability to obtain informed consent. Patients underwent concealed random allocation to a target glucose range of 5 to 7 or 8 to 10 mmol/L using pretested algorithms of insulin infusions. Dedicated glucometer measurement of arterial glucose values was calibrated daily to values measured in the laboratory. RESULTS: We enrolled 20 patients with a mean (SD) Acute Physiology and Chronic Health Evaluation (APACHE) II score of 32 (10.2); 14 were insulin-dependent pre-ICU, and all were medical admissions. Mean glucose values were different in the 2 groups (7.1 +/- 2.6 vs 9.4 +/- 2.1 mmol/L, P < .001). Although the intensive insulin therapy group had more glucose measurements performed than the control group, a similar proportion of values were within the target range (682 [42.4%] of 1607 values in the 5- to 7-mmol/L range; 250 [38.7%] of 660 values in the 8- to 10-mmol/L range, P = .35). Glucose values of less than 2.5 mmol/L developed 7 times in 5 patients, 4 of whom were in the intensive insulin therapy group; however, no adverse consequences were documented. As expected, there were no differences in clinically important outcomes. CONCLUSIONS: In this pilot trial of ICU patients with high illness severity, glucose values were in the 2 target ranges only 40% of the time, using well-accepted initiation and maintenance insulin infusion algorithms. A large randomized trial of glycemic control is feasible in this population to examine clinically important outcomes, but will require refined insulin algorithms and more comprehensive behavior change strategies to achieve target values.     

A(H1N1) pandemic influenza and its prevention by vaccination: Paediatricians' opinions before and after the beginning of the vaccination campaign

Background  

In June 2009, the World Health Organization declared an A(H1N1) influenza pandemic. In October 2009, the largest vaccination campaign in Canadian history began. The aim of this study was to document paediatricians' knowledge, attitudes and practices (KAP) regarding A(H1N1) pandemic influenza and its prevention by vaccination just after the beginning of the A(H1N1) vaccination campaign and to compare the results with those obtained before campaign initiation.     

High-Throughput Analysis of Antimalarial Susceptibility Data by the WorldWide Antimalarial Resistance Network (WWARN) In Vitro Analysis and Reporting Tool

Assessment of in vitro susceptibility is a fundamental component of antimalarial surveillance studies, but wide variations in the measurement of parasite growth and the calculation of inhibitory constants make comparisons of data from different laboratories difficult. Here we describe a Web-based, high-throughput in vitro analysis and reporting tool (IVART) generating inhibitory constants for large data sets. Fourteen primary data sets examining laboratory-determined susceptibility to artemisinin derivatives and artemisinin combination therapy partner drugs were collated from 11 laboratories. Drug concentrations associated with half-maximal inhibition of growth (IC₅₀s) were determined by a modified sigmoid E_max model-fitting algorithm, allowing standardized analysis of 7,350 concentration-inhibition assays involving 1,592 isolates. Examination of concentration-inhibition data revealed evidence of apparent paradoxical growth at high concentrations of nonartemisinin drugs, supporting amendment of the method for calculating the maximal drug effect in each assay. Criteria for defining more-reliable IC₅₀s based on estimated confidence intervals and growth ratios improved correlation coefficients for the drug pairs mefloquine-quinine and chloroquine-desethylamodiaquine in 9 of 11 and 8 of 8 data sets, respectively. Further analysis showed that maximal drug inhibition was higher for artemisinins than for other drugs, particularly in ELISA (enzyme-linked immunosorbent assay)-based assays, a finding consistent with the earlier onset of action of these drugs in the parasite life cycle. This is the first high-throughput analytical approach to apply consistent constraints and reliability criteria to large, diverse antimalarial susceptibility data sets. The data also illustrate the distinct biological properties of artemisinins and underline the need to apply more sensitive approaches to assessing in vitro susceptibility to these drugs.     

Clinical and Biochemical Evaluation of Patients with Hirsutism

Summary: Patients with moderate to severe hirsutism presenting over an 18-month period to an endocrine clinic were assessed by clinical evaluation and hormone measurements. Hair growth rate was estimated by a photographic technique and the severity of hirsutism graded using an objective scale. Of 43 patients, 9 had polycystic ovaries and the remainder were considered to have idiopathic hirsutism. The most severely affected group had significantly increased hair growth rates compared with less clinically affected subjects, and 47% of this group showed objective features of virilization. However, apart from a significantly higher 24-hr urine 17-ketosteroid excretion all other hormonal patterns were not significantly different between severely and mildly affected patients. Serum levels of testosterone (T), sex hormone-binding globulin (SHBG), free T (calculated from T and SHBG values), and androstenedione (A) were abnormal in 44%, 51%, 60% and 60% of patients respectively, whereas plasma levels of the specific adrenal androgen DHAS were increased in 40% of patients. There was an overlap between patients with elevated hormone levels, although isolated elevation of T, A or DHAS were seen in 9%, 19% and 3% of patients respectively. In 19% of patients all serum androgen measurements were normal. Gonadotrophin levels were significantly lower in the more severely affected group. Thus androgen levels in patients with idiopathic hirsutism or polycystic ovaries, show considerable overlap with measurements in normal subjects, and elevated plasma androgens may be of adrenal (DHAS) or combined adrenal/ovarian (T, A) origin.     

Mivacurium arteriovenous gradient during steady state infusion in anesthetized patients

BACKGROUND: Mivacurium and isomers undergo rapid hydrolysis by plasma cholinesterase. As this enzyme is largely distributed, it cannot be excluded that these isomers might undergo peripheral elimination. This hypothesis was investigated in patients by measuring the difference between arterial and venous concentrations under a constant-rate continuous infusion of mivacurium. METHODS: During propofol-remifentanil anesthesia, eight adult consenting patients received an intravenous bolus dose of 0.2 mg/kg mivacurium, followed by a constant infusion (3, 5, or 7 microg. kg. min ) into the brachial vein. One hour after starting the infusion, arterial (radial artery) and venous (contralateral brachial vein) blood samples were drawn simultaneously at 15-min intervals for 45 min. Mivacurium isomers and metabolite plasma concentrations were determined by stereospecific high-performance liquid chromatography. Using the corresponding arterial and venous concentrations, the tissue extraction coefficient as well as total body clearance were calculated. RESULTS: During steady state conditions, the venous concentrations of the and isomers were 34 +/- 13% and 42 +/- 11% (mean +/- SD) lower than the corresponding arterial concentrations (P < 0.05), respectively. For the isomer, the difference between venous and arterial concentrations was 3 +/- 4% (P = 0.063). Total body clearances of the and isomers were greater when based on venous sampling (P < 0.05). CONCLUSION: Pharmacokinetic parameters derived from a constant infusion of mivacurium depend heavily on the sampling site (arterial or venous) for the rapidly hydrolyzed isomers. These results strongly suggest a significant metabolism of mivacurium within muscle tissue that may account for the large interpatient variability in response to mivacurium.