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.     

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     

Occupational exposure of deck crews to carcinogenic agents on crude oil tankers

Occupational exposure to carcinogenic agents on the decks on six Norwegian crude oil tankers was examined in five harbors. The purpose of the study was to evaluate the need for improving the working environment on deck on these tankers. Technical arrangments and the work itself on the deck were observed during loading or unloading. Occupational monitoring was performed by active sampling of benzene, polyaromatic hydrocarbons, and some aldehydes. The crew answered a questionnaire concerning their work, use of protective equipment, and occurrence of acute symptoms. The levels of air-borne carcinogenic agents were low, probably due to closed loading systems on all tankers. However, the seamen reported discomfort during the work that may be related to other chemical agents in the cargo. The seamen were frequently painting with lead chromate paint without using personal protective equipment. This type of chemical exposure should be evaluated.     

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.     

Biological exposure limits estimated from relations between occupational styrene exposure during a workweek and excretion of mandelic and phenylglyoxylic acids in urine

Summary Styrene exposure of 18 workers in fiber-glass reinforced plastic industries was measured for 30-min periods throughout each workday for a week. The styrene uptake was estimated using pulmonary ventilation measurements. All urine voidings were collected separately and the styrene metabolites, mandelic acid (MA) and phenylglyoxylic acid (PGA) were determined. The relationship between both exposure and uptake versus excretion of these metabolites was studied. Styrene metabolite concentrations and excretion rates (with 95% tolerance limits) were calculated to correspond to a constant 8-h exposure at the Swedish exposure limit level (25 ppm) or an uptake of an exposure limit related styrene dose (6.3 mmol). The tightest tolerance limits were obtained for excretion rate of MA + PGA per 24 h. The calculated biological exposure limit was 3.4 (± 0.7) mmol MA + PGA/24 h for a dose of 6.3 mmol styrene.     

Oral estrogen retains potency as an aversion agent in eggs: implications to studies of community ecology and wildlife management.

The first of two experiments with laboratory rats demonstrated that oral estrogen (17 alpha-ethinylestradiol) can remain in the albumen of eggs at room temperature for up to 8 days with undiminished capacity to produce conditioned taste aversion. The second experiment showed that estrogen remains potent in the yolk of eggs for at least 4 days. There is now greater assurance that egg prey placed into the field will induce reliable CTA among mammalian predators. Community ecologists interested in such processes as competitive release and the responses of prey populations to reduced predation upon their eggs can selectively factor predation out of field experiments without the need for physically excluding predators. Wildlife biologists interested in reducing predation upon the eggs of endangered species now have greater assurance that estrogen-treated egg baits will suppress predation in a more cost-effective manner and with less likelihood of discrimination between treated eggs and those of endangered species.     

Gender differences in facial reactions to facial expressions

This study explored whether males and females differ in facial muscle reactivity when exposed to facial expressions. The study also examined whether the sex of the stimulus faces differentially influences the response patterns to facial stimuli. Thus, the sex was manipulated in a 2 x 2 factorial design by exposing males and females to slides of angry and happy faces displayed by both sexes. Facial electromyographic (EMG) activity was measured from the corrugator and zygomatic muscle regions. The subjects were also required to rate the stimuli on different dimensions. The results showed that angry faces evoked increased corrugator activity whereas happy faces evoked increased zygomatic activity. As predicted, these effects were more pronounced for females, particularly for the response to happy faces. Interestingly, there were no facial EMG effects for gender of stimulus. It was further found that males and females perceived the stimuli similarly. The results are consistent with previous findings indicating that females are more facially reactive than are males.