Monitoring cerebral oxygenation during balloon occlusion with multichannel NIRS

We report on oxygenation changes noninvasively recorded by multichannel continuous-wave near infrared spectroscopy (CW-NIRS) during endovascular neuroradiologic interventions requiring temporary balloon occlusion of arteries supplying the cerebral circulation. Digital subtraction angiography (DSA) provides reference data on the site, timing, and effectiveness of the flow stagnation as well as on the amount and direction of collateral circulation. This setting allows us to relate CW-NIRS findings to brain specific perfusion changes. We focused our analysis on the transition from normal perfusion to vessel occlusion, i.e., before hypoxia becomes clinically apparent. The localization of the maximal response correlated either with the core (occlusion of the middle cerebral artery) or with the watershed areas (occlusion of the internal carotid artery) of the respective vascular territories. In one patient with clinically and angiographically confirmed insufficient collateral flow during carotid artery occlusion, the total hemoglobin concentration became significantly asymmetric, with decreased values in the ipsilateral watershed area and contralaterally increased values. Multichannel CW-NIRS monitoring might serve as an objective and early predictive marker of critical perfusion changes during interventions—to prevent hypoxic damage of the brain. It also might provide valuable human reference data on oxygenation changes as they typically occur during acute stroke.     

Pharmacokinetic role of L-type amino acid transporters LAT1 and LAT2

LAT1 and LAT2 are heterodimeric large amino acid transporters that are expressed in various tissues, including the intestinal wall, blood-brain barrier, and kidney. These transporters consist of membrane spanning light chain and heavy chain, and they act as 1:1 exchangers in concert with other amino acid transporters. Only a few drugs (less than 10) are substrates of LAT1 and LAT2, including l-DOPA, alpha-methyldopa, melphalan, and gabapentin. The mechanisms and substrates have been mostly elucidated using mammalian cells and Xenopus oocytes. The in vivo relevance of LAT1 and LAT2 in pharmacokinetics is obscure, because contradictory findings have been reported. It is difficult to make quantitative pharmacokinetic conclusions about LAT1 and LAT2. This is due to the possible involvement of other transporters (including cross-linked heterodimers of light chain with different heavy chains, other overlapping transporters, for example TAT1), competing endogenous amino acids, and saturation phenomena. This review presents the current functional knowledge on LAT1 and LAT2 with emphasis on their potential involvement in pharmacokinetics.     

The effect of spraying and rolling process factors on styrene emission during the application of unsaturated polyester resins

In recent years the awareness of the problems caused by styrene emission during the processing of unsaturated polyester resins has enlarged. The spray-up application of gel coats is especially problematic, and it produces high styrene emission rates. The emission of styrene has been reduced through material changes, work practice controls, and add-on controls. However, the influence of the spray-up process factors on styrene emission has not been studied before. The aim of this study was to examine possibilities to reduce styrene emission by optimization of spray-up process factors. The following factors were studied under controlled laboratory conditions: orifice size and angle of the spray gun tip, spraying pressure, distance between spray gun and mold, and shape of the mold. The influence of the rolling pattern during lamination was also studied. Several significant factors were found. High pressure and long spraying distance increased both the unit styrene emission and the emission rate. The orifice size had two effects; a large orifice decreased the amount of styrene emitted per sprayed amount of resin but increased the emission rate of styrene. The shape of the mold did not affect the styrene emission. Styrene emission is greater if the entire mold area is rolled. To achieve lower emission is it necessary to roll an area as small as possible; this is especially important if a large mold is laminated. The results showed that emission of styrene can be reduced significantly by an optimal selection of the spray gun settings and the way of working. Optimal settings also increased the transfer efficiency resulting in decreased material loss.     

Serum insulin and leptin levels in valproate-associated obesity

PURPOSE: Weight gain is an important adverse effect of valproate (VPA) therapy, and it is associated with hyperinsulinemia and hyperandrogenism in women with epilepsy. Leptin is considered a signaling factor regulating body weight and energy metabolism. In human subjects, obesity is in general associated with elevated serum leptin levels, suggesting decreased sensitivity to leptin. The present study aimed at evaluating the role of insulin and leptin in VPA-related obesity. METHODS: Body mass index (BMI) was calculated, and serum insulin and leptin levels were measured in 81 patients with epilepsy taking VPA and in 51 healthy control subjects. RESULTS: Forty (49%) of the patients taking VPA and 25 (49%) of the control subjects were obese. The mean insulin levels were higher in VPA-treated patients than in the control subjects despite similar BMI values, when all subjects were included in the comparison. Both obese male and female patients taking VPA had higher serum insulin levels than the respective control subjects with similar BMI values. Serum insulin levels also were higher in lean male and lean female patients compared with the lean control subjects of same sex. Serum leptin levels did not differ between the VPA-treated patients and the control subjects. CONCLUSIONS: Both obese and lean patients taking VPA for epilepsy have hyperinsulinemia, suggesting development of insulin resistance. This may be one of the factors leading to weight gain during VPA treatment. However, the results of the present study do not suggest an independent role for leptin in the pathogenesis of VPA-related obesity.     

Serum hormones during prolonged training of neuromuscular performance

Summary The effects of a 24-weeks' progressive training of neuromuscular performance capacity on maximal strength and on hormone balance were investigated periodically in 21 male subjects during the course of the training and during a subsequent detraining period of 12 weeks. Great increases in maximal strength were noted during the first 20 weeks, followed by a plateau phase during the last 4 weeks of training. Testosterone/cortisol ratio increased during training. During the last 4 weeks of training changes in maximal strength correlated with the changes in testosterone/cortisol (P<0.01) and testosterone/SHBG (P<0.05) ratios. During detraining, correlative decreases were found between maximal strength and testosterone/cortisol ratio (P<0.05) as well as between the maximal strength and testosterone/SHBG ratio (P<0.05). No statistically significant changes were observed in the levels of serum estradiol, lutropin (LH), follitropin (FSH), prolactin, and somatotropin. The results suggest the importance of the balance between androgenic-anabolic activity and catabolizing effects of glucocorticoids during the course of vigorous strength training.     

No evidence of Mycoplasma pneumoniae in acute myringitis

Our aim was to discover Mycoplasma pneumoniae in bullous and hemorrhagic myringitis in children <2 years of age. Middle ear fluid samples (n = 37) and samples taken from the blisters of the tympanic membranes (n = 12) studied by polymerase chain reaction for M. pneumoniae were negative. This study does not support an important role for M. pneumoniae as an etiologic agent in acute myringitis.     

Epidemiology of choriocarcinoma in Finland, 1953 to 1999

OBJECTIVE: Choriocarcinoma is a rare tumor with remarkable differences in the incidence in various parts of the world. The available data do not elucidate recent time trends in the incidence of the disease in Western countries. We studied the epidemiology of choriocarcinoma in Finland over a period of 47 years. METHODS: Incidence rates for choriocarcinoma from 1953 to 1999, according to the population-based Finnish Cancer Registry, were calculated per number of deliveries, obtained from the National Research and Development Center for Welfare and Health. Standardized incidence ratios (SIRs) for the years 1971 through 1995 for women born between 1906 and 1945 were calculated by occupation taken from the 1970 Population Census. RESULTS: The incidence of choriocarcinoma was 40/10(6) deliveries for the study period 1953-1999 as a whole. The respective incidence rate calculated per female population and adjusted for age to the world standard population was 1.3/10(6). The incidence, per number of deliveries, was remarkably higher in women above 40 years as compared to younger women. There was a decline in the incidence of the disease in women between 25 and 39 years of age from 53/10(6) deliveries in 1953-1984 to 26/10(6) deliveries in 1985-1999. High occupation-specific risks were observed for nurses (SIR 7.8; 95% confidence interval 2.1-20) and agricultural workers (SIR 11; 95% confidence interval 1.4-40). CONCLUSION: The incidence of choriocarcinoma in Finland is similar to that reported earlier for other Western countries. The recent decline in the incidence of the disease, the enormous increase in the risk among old fertile women, and clustering of cases to certain occupations should be targets of future studies.     

Published evidence on the success of telecardiology: a mixed record

We carried out a systematic review of the literature on telecardiology assessment from 1992 to September 2003. We selected articles reporting clinical, economic or administrative outcomes. Quality of evidence was assessed using an approach that considered both study design and study performance. Forty-four studies met the selection criteria. Studies of home care applications, particularly management of congestive heart failure, were of highest quality, giving a high degree of confidence in their findings. Studies on paediatric and non-emergency adult hospital applications were of poorer quality; they were mostly reports of case series and gave relatively little detail. Economic analysis was limited to cost studies and in most cases was judged to be of poor to fair quality. While telecardiology has been widely applied, there is still limited good-quality evidence of its benefits to health-care. Success in establishing the feasibility of telecardiology applications is offset by a failure to obtain convincing data on their influence on health outcomes and on their cost-effectiveness.