Early computed tomographic scanning after resection of brain tumors in children

Enhanced and non-enhanced computed tomography (CT) brain scans were performed within 72 h of surgery on 21 children in whom brain tumors had been resected totally or subtotally, and scans were repeated at varying intervals thereafter. Biopsies of the resection margins were performed in 12 patients at the end of the surgical procedure. The immediate CT scan showed enhancement in the resection margin in 13 of the 21 patients and in 9 of the 13, the enhancement disappeared on follow-up scans. There was discordance between the results of immediate CT scan examination and the biopsies of the resection margins in 7 of the 12 cases. The advantages and disadvantages of an immediate postoperative scan versus a more delayed CT scan are discussed.     

Peritoneal dialysis patient survival: a comparison between a Swedish and a Korean centre.

BACKGROUND: Dialysis patient mortality remains high, and this high mortality may be due to many factors. In peritoneal dialysis (PD) patients, old age, co-morbid diseases, malnutrition, low residual renal function (RRF) and a high peritoneal transport rate have been shown to influence survival, but the relative importance of these factors may differ between different patient populations. Besides, centre practice patterns may differ between centres and may influence patient survival. In addition, the literature suggests that dialysis patient survival may be better in Asian than in Caucasian patients. METHODS: The influence of centre and patient characteristics on patient survival was investigated in 132 Korean and 106 Swedish incident PD patients, who underwent initial biochemical measurements and assessment of adequacy of dialysis, nutritional status, RRF and peritoneal transport characteristics. RESULTS: At the start of PD, Korean patients had a higher prevalence of diabetes, peritoneal Kt/V(urea), peritoneal creatinine clearance and peritoneal fluid removal, and lower body mass index, RRF and dialysate to plasma creatinine concentration ratio (D/P Cr) compared with Swedish patients. Significantly more patients from Korea were placed on temporary haemodialysis before PD (100 out of 132) when compared with Swedish patients (21 out of 106). During the follow-up, there was a significantly higher rate of transfer to other units in Korea and a significantly higher rate of kidney transplantation in Sweden. On Kaplan-Meier analysis, overall patient survival did not differ and relative risk for death was also not different between the two centres even after adjustment for age, diabetes, cardiovascular disease, RRF and D/P Cr. On Cox proportional hazards multivariate analysis, age, diabetes, RRF and D/P Cr were found to be independent predictors of mortality in the combined cohort of patients. While age, diabetes and D/P Cr were independent predictors of mortality in Korean patients, age and RRF independently predicted mortality in Swedish patients. CONCLUSION: Although there were significant differences in centre and patient characteristics, we were unable to confirm a survival advantage for Korean over Swedish PD patients. The results of this study suggest that the reported difference in survival between Asian and Caucasian dialysis patients may have been due, in part, to differences in centre and patient characteristics rather than to race as such. The genetic influence on patient characteristics remains, however, to be elucidated.     

Densities in dependent lung regions during anaesthesia: atelectasis or fluid accumulation?

In previous studied with computed tomography (CT) prior to and during general anaesthesia, we found that densities developed in dependent parts of the lungs immediately after induction of anaesthesia in all examined patients. It was suggested that the densities were atelectases created by compression of lung tissue but an alternative explanation could be accumulation of extravascular fluid in the lung tissue and/or in the pleural space. In the present study the nature of the densities was analysed in further detail. Injections of contrast medium into the pleural space revealed that the densities were located in the lung tissue and not in the pleural space. By injecting contrast medium intravenously and repeating the CT scanning over a 2-min period the passage of contrast through the major vessels and the lung densities could be studied. The transit time of the contrast medium was of the same magnitude in the densities and the major lung vessels. This indicates that there were no regions with an increased amount of extravascular fluid to delay the contrast passage. These findings oppose the idea of fluid accumulation as the cause of the densities, while atelectasis remains the most plausible explanation.     

Distinct Pharmacologic Properties of Neuromuscular Blocking Agents on Human Neuronal Nicotinic Acetylcholine Receptors: A Possible Explanation for the Train-of-four Fade

Background: Nondepolarizing neuromuscular blocking agents (NMBAs) are extensively used in the practice of anesthesia and intensive care medicine. Their primary site of action is at the postsynaptic nicotinic acetylcholine receptor (nAChR) in the neuromuscular junction, but their action on neuronal nAChRs have not been fully evaluated. Furthermore, observed adverse effects of nondepolarizing NMBAs might originate from an interaction with neuronal nAChRs. The aim of this study was to examine the effect of clinically used nondepolarizing NMBAs on muscle and neuronal nAChR subtypes.

Methods: Xenopus laevis oocytes were injected with messenger RNA encoding for the subunits included in the human [alpha]1[beta]1[varepsilon][delta], [alpha]3[beta]2, [alpha]3[beta]4, [alpha]4[beta]2, and [alpha]7 nAChR subtypes. The interactions between each of these nAChR subtypes and atracurium, cisatracurium, d-tubocurarine, mivacurium, pancuronium, rocuronium, and vecuronium were studied using an eight-channel two-electrode voltage clamp setup. Responses were measured as peak current and net charge.

Results: All nondepolarizing NMBAs inhibited both muscle and neuronal nAChRs. The neuronal nAChRs were reversibly and concentration-dependently inhibited in the low micromolar range. The mechanism (i.e., competitive vs. noncompetitive) of the block at the neuronal nAChRs was dependent both on subtype and the NMBA tested. The authors did not observe activation of the nAChR subtypes by any of the NMBAs tested.     

Glucose concentration in the vitreous of nondiabetic and diabetic human eyes

Glycation (nonenzymatic glucosylation) of collagen may play a role in the primary pathology of the vitreous in diabetes. The extent of glycation is determined by the glucose concentration in the tissue. In this study glucose concentration was assayed in blood and vitreous samples obtained from three patient groups undergoing vitrectomy: nondiabetic patients (ND), diabetic patients with insulin-dependent diabetes mellitus (IDDM) and diabetic patients with non-insulin-dependent diabetes mellitus (NIDDM). In the ND group the glucose concentration in the vitreous (3.5 +- 1.8 mM/1) was always lower than in the blood (9.1 +- 3.5 mM/1). In the diabetic groups the vitreous glucose concentration was, with a few exceptions, generally lower than the blood glucose concentration. The vitreous glucose concentration in these groups was generally higher (IDDM 9.4+-3.3 mM/1, NIDDM 7.2+-3.9 mM/1) than in the ND group, and in 15 specimens exceeded 11 mM/1, a level increasing the probability of collagen glycation in the vitreous of diabetic patients.This study was given financial support by the Herman Järnhardt Foundation, the Inez and Joel Carlsson Foundation and by Diabetesföreningen in Malmö     

Natural killer cell activity and CSF monoamine metabolites in suicide attempters

The aim of this study was to investigate markers of serotonin and immune function in suicidal patients. Cytotoxic activity of natural killer cells (NK) and CD16 lymphocytes were studied in 28 suicide attempters and 26 healthy controls, and related in patients to 5-hydroxyindoleacetic acid (5-HIAA) in cerebrospinal fluid (CSF). Patients with CSF 5-HIAA below the median had significantly lower NK cell activity than other patients. CD16 cell frequency was significantly lower in patients than in controls, and patients also tended to have lower NK cell cytotoxicity than healthy controls. There were no statistically significant correlations between 4-hydroxy-3methoxyphenyl glycol (HMPG), homovanillic acid (HVA), CSF cortisol and NK cell activity. The results support the hypothesis of compromised immune function in suicidal patients with evidence of disordered serotonin function.     

The effect of various thermal processes on the glycemic response to whole grain wheat products in humans and rats

The effects of different thermal processes used to produce ready-to-eat cereals on the glycemic response to whole grain wheat were investigated in rats. The metabolic response to drum dried flour, which constitutes the major component in instant gruel and porridge, was also studied in healthy human subjects. Boiled flour was used for comparison. The degree of starch gelatinization and rate of starch hydrolysis in vitro were also measured. Incompletely gelatinized steam flaked and dry autoclaved products were digested more slowly in vitro and elicited lower glucose responses in rats compared with completely gelatinized drum dried, extrusion cooked or boiled samples. The initial glycemic response in rats was closely related to the rate of starch hydrolysis in the pepsin/alpha-amylase assay (r = 0.91, P less than 0.04). When pepsin was omitted, no significant correlation was obtained. The peak glucose, insulin and C-peptide responses in humans after breakfast meals of porridge prepared from drum dried flour and from boiled flour were similar, whereas the rate of depression of the glucose curve was more rapid after consuming drum dried porridge. It is concluded that the glycemic response to wheat products is affected by the processing conditions used. The more severe the processing conditions, the more rapid the digestion of starch.     

Glycogen and glycogen-hydrolysing lysosomal enzyme activity in mouse liver: effects of fasting, adrenoceptor antagonism and insulin-induced hypoglycaemia

Whereas the phosphorolytic breakdown of liver glycogen is known to be of great physiological importance, the functional role of the hydrolytic glycogenolysis in the lysosomal system is less well understood. In the present study the effects of fasting, alpha- and beta-adrenoceptor antagonism and insulin-induced hypoglycaemia on liver lysosomal glycogen-hydrolysing enzyme activity were investigated in mice. In freely fed mice the glycogen-hydrolysing activity (acid amyloglucosidase) was only 50% of the maltose-hydrolysing activity (acid maltase). Starvation for 24 h reduced the acid amyloglucosidase activity by approximately 30% (P less than 0.001), whereas the activities of acid maltase, acid phosphatase and beta-glucuronidase appeared unaffected. N-acetyl-beta-D-glucosaminidase activity was moderately (20%; P less than 0.01) enhanced by fasting. Thus, liver lysosomal enzyme activities may change independently of each other during fasting. Further, during short-term hypoglycaemic conditions (45 min) induced by endogenous or exogenous insulin, the activity of liver acid amyloglucosidase was found to be moderately reduced (15-20%). Blockade of alpha- and beta-adrenoceptors by phentolamine and propranolol did not result in any apparent influence on acid amyloglucosidase activity except for the indirect effect exerted by the phentolamine-induced hypoglycaemia. A moderate negative correlation (r = -0.51; P less than 0.001) between total liver glycogen concentration and acid amyloglucosidase activity was observed in a series of 43 freely fed NMRI mice. Our data show that in mouse liver the acid maltase activity predominates over the acid amyloglucosidase activity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Neuropeptide Y and calcitonin gene-related peptide: effects on glucagon and insulin secretion in the mouse

Neuropeptide Y (NPY) and calcitonin gene-related peptide (CGRP) are both intrapancreatic neuropeptides that are known to inhibit stimulated insulin secretion. In the present study, we examined their influences on basal and stimulated glucagon and insulin secretion in the mouse. Either NPY or CGRP was injected intravenously at two dose levels (0.85 or 4.25 nmol/kg). When injected alone, neither of them did affect basal plasma glucagon levels but CGRP reduced basal plasma insulin levels. Glucagon secretion stimulated by the cholinergic agonist carbachol was modestly inhibited by NPY at 4.25 nmol/kg (P less than 0.01) but not affected by CGRP. In contrast, glucagon secretion stimulated by the beta 2-adrenoceptor agonist terbutaline was markedly inhibited by NPY already at the lower dose level (P less than 0.01) and potentiated by CGRP (P less than 0.01). Insulin secretion stimulated by carbachol was inhibited by CGRP (P less than 0.01) but not affected by NPY, whereas terbutaline-induced insulin secretion was inhibited by both NPY (P less than 0.05) and CGRP (P less than 0.01). We conclude that the two intrapancreatic neuropeptides NPY and CGRP have opposite actions on stimulated glucagon secretion in the mouse: NPY in an inhibitory and CGRP in a potentiatory direction. Both peptides, however, inhibit insulin secretion stimulated by terbutaline.