Determination of 3,4-dihydroxyphenylalanine (DOPA) in plasma and cerebrospinal fluid by high performance liquid chromatography with electrochemical detection

We report a reliable method for determining DOPA levels in plasma and cerebrospinal fluid. The method is based on complete conversion of DOPA to dopamine and quantification by HPLC-ECD of the dopamine formed. Lower limit of detection was 0.5 nmol/l. No differences in plasma DOPA levels were found between normal children (0-15 yr, n = 60), normal adults (n = 39) and patients with essential hypertension (n = 40) or Parkinson's disease (no DOPA therapy, n = 30). In normal individuals and in patients with essential hypertension venous plasma levels were higher than arterial levels (10.2 vs 9.3 nmol/l, p less than 0.001, V/A ratio 1.11 (SD 0.08), n = 15). Sympathetic stimuli (standing, tilting, bicycle exercise, tyramine) did not influence DOPA levels. In untreated depressed patients (n = 10) and in non-parkinsonian neurological patients (n = 12) cerebrospinal fluid levels of DOPA were 4.5 (SD 2.4) and 5.2 (SD 1.3) nmol/l respectively. A direct method for the measurement of DOPA by HPLC-ECD after deproteinization of plasma is also described and compared with the conversion method. Good agreement was found when plasma DOPA levels exceeded 0.25 mumol/l (y(conversion method) = 0.943x (direct method) + 0.118; n = 60; r = 0.985). The direct method, because of greater simplicity and the possibility of simultaneous measurement of the DOPA metabolite 3-O-methyldopa, is the method of choice with plasma samples from DOPA-treated patients. In non-DOPA treated individuals the conversion method is superior and has proved to be an accurate and sensitive method for the determination of DOPA levels in plasma and cerebrospinal fluid.     

Chronic fatigue of the small enterprise workers participating in an occupational health checkup center in southern Taiwan

Purpose  There has been increasing interest in the occupational health of workers in small enterprises, especially in developing countries. This study examines the association between psychosocial job characteristics and fatigue, and attempts to identify risk factors for fatigue among workers of small enterprises in southern Taiwan. Methods  A structured questionnaire was administered to workers receiving regular health examinations between August 2005 and January 2006. The questionnaire collected demographic information and data on working conditions, personal health status and life styles. It also collected information on psychosocial job characteristics, fatigue and psychological distress using three instruments. Results  A total of 647 workers with mean age of 43.7 were completed. Probable fatigue was found in 34.6% of the sample. Fatigue was found by multiple logistic regressions to be associated with the lack of exercise, working in shifts, depression score and lack of social support at workplace. Conclusions  This study found associations between life style, psychosocial job characteristics and fatigue. Because the high prevalence of probable fatigue was found in such small enterprises, the authors suggest that a short interview with some quick questionnaires in health checkup for these small enterprise workers are helpful to early detect psychosocial and fatigue problems.     

胰岛素瘤的超声诊断:与其他诊断方法比较

目的:探讨超声等方法对胰岛素瘤的定位诊断价值。材料和方法:对42例经过手术和病理证实的胰岛素瘤患者术前定位诊断的各种方法进行回顾性分析,并与其他诊断方法对比分析其各自的定位符合率。结果:定位诊断符合率分别为B超31%(13/42)、EUS55.6%(5/9)、IOUS100%(10/10)、超声引导下PTPC100%(3/3)、CT59.5%(25/42)、MRI50%(6/12)、选择性DSA27.3%(3/11)及ASVS90%(9/10)。彩超(CDUS)对胰岛素瘤良、恶性有鉴别作用。结论:遵循循序渐进原则,先后选用B超(含CDUS)、EUS、CT等已可解决80%以上的定位诊断,然后再做MRI及ASVS;对仍未作出定位者,只要定性诊断明确即有手术探查指征,因为IOUS能提供可靠的定位信息。     

Comparison of the effects of three different combinations of general anesthetics on the electroretinogram of dogs

The objective of this study is to compare the effects of three different anesthetic combinations on the electroretinogram in the same animals under similar laboratory conditions. Thiopental–isoflurane (TI), medetomidine–ketamine (MK), and xylazine–ketamine (XK) were used on each of 12 healthy miniature schnauzer dogs (MS) with a period of at least 3 weeks in between subsequent anesthesia protocols, using the Dog Standard Protocol. The scotopic ERGs consisted of scotopic low stimulus strength (S) responses designated S1, S2, S3, S4, and S5, at 1, 5, 10, 15, and 20 min after dark adaptation, respectively, and scotopic standard stimulus strength (S-ST) responses. The photopic ERGs consisted of a photopic single flash (P) response and 31 Hz flicker (P-FL) responses. For S-ST (2.5 cd s/m²), the amplitude of the a-wave using TI was significantly lower than that using MK (adjusted P = 0.05) and XK (adjusted P = 0.03), and the implicit time of the a-wave was significantly shorter than that using MK (adjusted P = 0.04). For P (2.5 cd s/m²), the amplitude of the b-wave using XK was significantly higher than that using MK (adjusted P = 0.01). The implicit times of the b-wave using TI was significantly longer and shorter than that of MK for S1, S2 and P-FL and for S4 and S-ST, respectively, and than that of XK for S2 and P-FL and for S5 and S-ST, respectively. The results of the present study showed that TI affected both the amplitude and the implicit time of the a-wave for S-ST and the implicit time of the b-wave relatively more so than was the case when using XK or MK. Therefore, it appears that either XK or MK could be advantageous to use rather than TI for clinical studies.     

Pediatric traumatic brain injuries in Taiwan: an 8-year study.

Background. This study is intended to determine the causes of pediatric traumatic brain injuries (PTBI) in children aged 14 years or less, and to identify various types of craniocerebral damage resulting from different mechanisms of injury.Methods. From July 1, 1993 to June 30, 2001, a survey on PTBI was conducted in Taiwan. The data of patients used in this study were collected from 56 major hospitals among the age group of 0-14 years. The items in the traumatic brain injury survey included sex, age, causes of injuries, severity, and the eventual outcome.Results. A total of 5349 cases were identified. The male-to-female ratio was 1.69: 1. The incidence rate was higher in the age groups of 4-9 years and 10-14 years. The main cause of PTBI was traffic injury, which accounted for 2537 of the cases (47.3%), followed by falls, 2160 (40.3%). Of all traffic injuries, motorcycle-related injury had the highest incidence, followed by the pedestrian and bicycle-related injury. This study also showed that 83.2% of the patients had mild injury, 9.8% had moderate injury, and 7.0%, severe injury.Conclusions. The results of this study suggest that it is important to decrease all the risk factors in the environment of homes and public areas as much as possible. Helmet wearing and the development of public transportation are essential for the prevention of head injury.