Chlorination disinfection by-products and pancreatic cancer risk

Chlorination disinfection by-products (CDBPs) are produced during the treatment of water with chlorine to remove bacterial contamination. CDBPs have been associated with an increased risk of bladder cancer. There is also some evidence that they may increase the risk of pancreatic cancer. We report results from a population-based case-control study of 486 incident cases of pancreatic cancer and 3,596 age- and sex-matched controls. Exposure to chlorination by-products was estimated by linking lifetime residential histories to two different databases containing information on CDBP levels in municipal water supplies. Logistic regression analysis found no evidence of increased pancreatic cancer risk at higher CDBP concentrations (all odds ratios < 1.3). Null findings were also obtained assuming a latency period for pancreatic cancer induction of 3, 8, or 13 years.

Chemo-enzymatic synthesis of N-arachidonoyl glycine

N-Arachidonoyl glycine was synthesized in a chemo-enzymatic process where glycine tert -butyl ester was acylated by arachidonic acid and the resulted ester was then de-protected to give the final product. Among various lipases tested and chosen for their ability to cleave fatty amides, that from Candida antarctica B gave the best results resulting in a 39% hydrolysis after 24 h. This enzyme was then used for the reverse N-acylation synthesis and gave a 75% product formation after 24 h using methyl ester of arachadonic acid as acyl donor and acetonitrile as solvent. Direct acylation of glycine gave less than 10% yield.

Toward the synthesis of pyroglutamate lauroyl ester: biocatalysis versus chemical catalysis

The synthesis of dodecyl pyroglutamate (or pyroglutamate lauroyl ester) was achieved in a two-step process involving a pyroglutamic acid alkyl ester intermediate. The reaction was carried out either by lipase or by chemical catalysis using ion exchange resin. Among the various tested lipases, the one from Candida antarctica B gave the best results allowing 73% formation of the desired ester after 6 h. Comparing the efficiency of this latter lipase with the one of Amberlyst IR120H resin in catalyzing this reaction, the biocatalyst gave a molar yield of pyroglutamate lauroyl ester of 79% compared to 69% when using the ion exchange resin starting with 1.04 mmol substrate in each case.

Immunohistochemical evidence for the implication of PC1 in the processing of proneurotensin in rat brain

Biochemical studies have shown that prohormone convertases PC1, PC2 and PC5A all have the capacity to process, with different specificities, the neurotensin/neuromedin N precursor, pro-NT/NN. A previous study from our laboratory has demonstrated that in rat brain, both PC2 and PC5A may be co-expressed with NT, lending support to a physiological implication of these two enzymes in the endoproteolytic maturation of pro-NT/NN. In the present study, we sought to determine whether PC1 might also be involved in this process by comparing the immunohistochemical distribution of the enzyme with that of NT in both singly labeled and dually labeled serial brain sections. PC1 was found to co-localize extensively with NT throughout the rat neuraxis. However, there were important regional variations in the proportion of NT neurons co-expressing PC1. Furthermore, this proportion was negatively correlated with that of NT neurons expressing PC5, suggesting that PC1 may serve as an alternative to PC5A for processing pro-NT/NN in mammalian brain.

Immunohistochemical evidence for the involvement of protein convertases 5A and 2 in the processing of pro-neurotensin in rat brain

The neuropeptides/neurotransmitters neurotensin (NT) and neuromedin (NN) are synthesized by endoproteolytic cleavage of a common inactive precursor, pro-NT/NN. In vitro studies have suggested that the prohormone convertases PC5A and PC2 might both be involved in this process. In the present study, we used dual immunohistochemical techniques to determine whether either one or both of these two convertases were co-localized with pro-NT/NN maturation products and could therefore be involved in the physiological processing of this propeptide in rat brain. PC2-immunoreactive neurons were present in all regions immunopositive for NT. All but three regions expressing NT were also immunopositive for PC5A. Dual localization of NT with either convertase revealed that NT was extensively co-localized with both PC5A and PC2, albeit with regional differences. These results strongly suggest that PC5A and PC2 may play a key role in the maturation of pro-NT/NN in mammalian brain. The regional variability in NT/PC co-localization patterns may account for the region-specific maturation profiles previously reported for pro-NT/NN. The high degree of overlap between PC5A and PC2 in most NT-rich areas further suggests that these two convertases may act jointly to process pro-NT/NN. At the subcellular level, PC5A was largely co-localized with the mid-cisternae Golgi marker MG-160. By contrast, PC2 was almost completely excluded from MG-160-immunoreactive compartments. These results suggest that PC5A, which is particularly efficient at cleaving the two C-terminal-most dibasics of pro-NT/NN, may be acting as early as in the Golgi apparatus to release NT, whereas PC2, which is considerably more active than PC5A in cleaving the third C-terminal doublet, may be predominantly involved further distally along the secretory pathway to release NN.

Risk factors associated with alpine skiing injuries in children. A case-control study

We investigated the relative contribution of four risk factors to the occurrence of injuries among alpine skiers aged 12 years and younger (3 to 12 years old; mean age, 9.43 years). The risk factors selected were deficient binding adjustment, absence of formal training, low skill level, and use of rented equipment. A group of injured skiers (N = 41) and a control group of uninjured skiers (N = 313) were recruited among young skiers at one major alpine ski center in the Quebec City, Canada, area during the 1995 to 1996 season. No significant group differences were found for mean age or sex distribution. The adjusted odds ratios for injury were 7.54 (95% confidence interval [2.57, 22.15]) for skiers in the low level of skill category relative to highly skilled skiers, 7.14 (2.59, 19.87) for skiers who rented their ski equipment compared with skiers who owned their equipment, and 2.11 (1.02, 4.33) for skiers with ill-adjusted bindings compared with skiers with better-adjusted bindings. Only formal training did not meet the 0.05 significance level for entry into the model; this is probably because of methodologic limitations. Implications of these results for the development of a prevention program aimed at young skiers are discussed.

Ovarian follicular growth and maturity and follicular production of progesterone and oestradiol in response to porcine luteinising hormone and porcine follicle stimulating hormone in albino (S*AS) hens in vivo and in vitro

The effects of the SAS gene on follicular growth were studied by feeding Sudan IV and Sudan Black B, on follicular maturity by measuring P4 and E2 output of the 5 largest follicles (F1 to F5) in vitro, and on ovarian response (plasma progesterone, P4, and oestradiol, E2) to administration of porcine follicle-stimulating hormone (pFSH) and porcine luteinising hormone (pLH) in old laying hens. Albino hens had fewer dye rings in the yolks of their eggs than non-albinos (8.32 compared to 8.59) and the yolks from albinos weighed less. The numbers of normal and atretic follicles larger than 3 mm in diameter did not differ between the two genotypes. The P4 outputs from the F1 and F2 follicles were significantly greater for albino hens, but P4 production of other follicles was not different for the two genotypes. The P4 output of the F1 follicle in response to pLH was dose-dependent and greater for albino hens than for non-albinos. Porcine LH did not increase the follicular E2 output in either genotype. Administration of pLH, but not pFSH, increased plasma P4 and E2 concentrations, with no difference between genotypes. These data suggest that the F1 follicles for albino hens are precocious, resulting in a reduced growth period and a smaller weight at ovulation.

Immunohistochemical distribution of the prohormone convertase PC5-A in rat brain

Prohormone convertase 5 is an endoprotease of the kexin/subtilisin-like family, which has been postulated to play a role in the proteolytic maturation of a variety of pro-peptides in the mammalian brain. In order to gain insight into the functional role of prohormone convertase 5 in the central nervous system, the regional, cellular and subcellular distributions of the enzyme were investigated by immunohistochemistry in rat brain using an N-terminal-directed specific antibody shown previously to recognize both the mature and unprocessed forms of the enzyme. Throughout the brain, prohormone convertase 5 immunoreactivity was concentrated within nerve cell bodies and proximal dendrites. No prohormone convertase 5 immunoreactivity was associated with astrocytes, as confirmed by the absence of prohormone convertase 5 immunolabeling in cells immunopositive for the glial protein S-100alpha. Within neurons, prohormone convertase 5 immunoreactivity was concentrated within the Golgi apparatus, as revealed immunohistochemically within the same sections using antibodies against the medial cisternae protein MG-160. It was also present within small vesicular-like elements distributed throughout the cytoplasm of perikarya and dendrites, but not of axons, as confirmed by its lack of co-localization with the synaptic terminal marker Dynamin-1. These results suggest that prohormone convertase 5 is active within early compartments of the neuronal regulated secretory pathway and that it is unlikely to be released with its processed substrates. At the regional level, prohormone convertase 5-immunoreactive perikarya were distributed extensively throughout the forebrain. The most numerous and intensely labeled were detected in the olfactory bulb, cerebral cortex, globus pallidus, endopeduncular and subthalamic nuclei, septum, diagonal band of Broca, magnocellular and medial preoptic areas, supraoptic and arcuate nuclei of the hypothalamus, and anterodorsal, laterodorsal, paraventricular and reticular nuclei of the thalamus. Moderate to dense neuronal labeling was also evident in the olfactory tubercle, caudate-putamen, claustrum, bed nucleus of the stria terminalis, substantia innominata, hippocampus, amygdala, and remaining thalamic and hypothalamic nuclei. This widespread distribution suggests that prohormone convertase 5 is involved in the processing of a variety of neuropeptide and/or neurotrophin precursors in mammalian brain.

Channel drop filters in photonic crystals

We present a general analysis of channel drop filter structures composed of two waveguides and an optical resonator system. We show that 100% transfer between the two waveguides can occur by creating resonant states of different symmetry, and by forcing an accidental degeneracy between them. The degeneracy must exist in both the real and imaginary parts of the frequency. Based on the analysis we present novel photonic crystal channel drop filters. Numerical simulations demonstrate that these filters exhibit ideal transfer characteristics.

A novel culturing and grafting system for the treatment of leg ulcers

The purpose of this study was to develop and test an efficient culturing and grafting system for the treatment of leg ulcers. The culturing system consisted of a Petriperm culture vessel (20 cm2) aseptically placed in a larger standard Petri dish (60 cm2). Skin cultures were established and cultivated in the Petriperm dish. The cells grew on the bottom of the Petriperm dish, which was made of a gas-permeable 25-micron thick transparent Teflon film. Grafts were produced simply by cutting the film from the bottom of the Petriperm dish with a scalpel. The system was used to produce subconfluent epidermal autografts which were used to heal a 32 cm2 chronic rheumatoid arthritis leg ulcer. The cultured autografts were transferred cell side down on to the cleaned wound bed without an enzymatic digestion. The grafts consisted of autologous keratinocytes, melanocytes and fibroblasts. Caution was taken not to disturb the wound bed for 7-9 days at which time the Teflon film was removed. The wound closed 2 weeks after the last grafting and has remained closed for more than a year post-treatment. The culturing and grafting system presented here will make it possible to develop cellular-based therapies that were previously not possible.

Sensory presynaptic and widespread somatodendritic immunolocalization of central ionotropic P2X ATP receptors

Recent evidence suggests that extracellular ATP plays a neurotransmitter role in the central nervous system. Its fast ionotropic effects are exerted through a family of P2X ATP-gated channels expressed in brain and spinal cord. To determine the physiological significance of central ATP receptors, we have investigated the localization of a major neuronal P2X receptor at the cellular and subcellular levels using affinity-purified antibodies directed against the C-terminal domain of P2X4 subunit. Subunit-specific anti-P2X4 antibodies detected a single band of 57,000 +/- 3000 mol. wt in transfected HEK-293 cells and in homogenates from adult rat brain. The strongest expression of central P2X receptors was observed in the olfactory bulb, lateral septum, cerebellum and spinal cord. P2X4 immunoreactivity was also evident in widespread areas including the cerebral cortex, hippocampus, thalamus and brainstem. In all regions examined, P2X receptors were associated with perikarya and dendrites where they were concentrated at the level of afferent synaptic junctions, confirming a direct involvement of postsynaptic ATP-gated channels in fast excitatory purinergic transmission. Moreover, P2X4-containing purinoceptors were localized in axon terminals in the olfactory bulb and in the substantia gelatinosa of nucleus caudalis of the medulla and dorsal horn of the spinal cord, demonstrating an important selective presynaptic role of ATP in the modulation of neurotransmitter release in central sensory systems.

The effect of strain of broiler on physiological parameters associated with the ascites syndrome

Differences among eight commercial broiler strains in factors indicating susceptibility to ascites were investigated. Chicks from eight crosses were obtained from two hatcheries (one was obtained from both hatcheries to give a total of nine) and raised to 6 wk of age on commercially prepared rations containing 3,300 kcal/kg energy with 24% protein to 3 wk of age and 20% protein from 3 to 6 wk. Each cross was represented by four pens of 90 broilers each. At 21 and 42 d, groups of 20 birds per pen were weighed and feed consumption was measured in order to calculate the feed conversion ratio. At 21 and 42 d, a blood sample was taken from two birds per pen to determine the hematocrit value. These birds were killed and dissected to determine heart, liver, lung, and spleen weights. Lung volume was determined by water displacement. Significant differences were observed between crosses for all of the measures with the exception of feed conversion ratio and mortality. These differences were most prominent for hematocrit value, which is an initial adaptation to anoxia, suggesting that broiler lines could be chosen that resist anoxic environmental conditions.

Determination of pregastric lipase specificity in young ruminants

The combined hydrolysis of a chiral triglyceride clearly defined on these three positions and of its racemic equivalent reveals all sorts of lipase specificities: regioselectivity, typoselectivity and stereospecificity. This article describes a study of the pregastric lipases of young ruminants (kid, calf, lamb), whose specificity is still somewhat ambiguous. The use of a chiral triglyceride in which position sn 1 was occupied by a short-chain fatty acid showed that these lipases had dual specificity, i.e. a combination of typoselectivity with respect to short-chain fatty acids and sn3 stereospecificity. A comparison between the performance of the lipase of young animals and the fatty acid composition and distribution in the mother's milk suggests that the degree of dual specificity in these enzymes is related to the characteristics of the mother's milk.

Trends in mammography and Pap smear utilization in Canada

We have examined trends in the utilization of two preventive health procedures for women in Canada based on our analysis of the 1994 National Population Health Survey (NPHS) and comparisons with two previous large population health surveys. The NPHS provides evidence that Canadian women's use of mammography has continued to increase between 1990 and 1994, while use of Pap smears has remained steady. Increases in mammographic utilization are seen for all age groups and in all provinces of Canada. Women who are less than the recommended age of 50-69 years for screening mammography access these services in considerable numbers. Large proportions of women aged 18-24 and 65 or over have never had a Pap smear, and recency of Pap smear is associated with age. Income adequacy and educational attainment are still strong predictors of which women utilize Pap smears and mammograms. We conclude that the NPHS is sufficiently broad-based to be used in a surveillance program to track Pap smear and mammography utilization.

Effects of sex-linked imperfect albinism (sal-s) in the chicken on the relationships of plasma concentrations of progesterone and 17 beta-estradiol with egg production

Effects of the sal-s gene for sex-linked imperfect albinism on the relationships of plasma concentrations of progesterone (P4) and estradiol (E2) with egg production were investigated during the laying period. Egg production of 17 albino and 16 nonalbino hens was recorded from 19 to 60 wk of age. Blood samples of these hens were taken between 1330 and 1500 h at 19 and 20 wk of age and every 4 wk until 60 wk of age. At 61 wk, blood samples were taken 6, 5, and 4 h before a midsequence ovulation. Plasma P4 and E2 were measured by RIA. There was no difference between genotypes in days to first egg (157.8 vs 158.1 d). Hen-day egg production of albinos was greater (P < 0.05) than that of nonalbinos in the 4-wk periods between 52 and 56 wk (83.8 vs 69.2%) and 56 and 60 wk (81.3 vs 64.3%). Egg production for the entire laying cycle was not different between genotypes (81.0 vs 73.0%, P = 0.08). Plasma P4 and E2 concentrations were not different between albino and nonalbino hens. From 28 to 60 wk of age, partial correlation coefficients between P4 and egg production, and E2 and egg weight were significant for albino hens (r = 0.15 and 0.16, respectively) but not for nonalbinos (r = -0.03 and -0.1, respectively), and age and P4 concentrations were negatively correlated for both albinos (r = -0.22, P < 0.01) and nonalbinos (r = -0.32, P < 0.01). Preovulatory levels of P4 in albino hens were higher (P < 0.05) than those in nonalbinos. Plasma E2 was higher in albinos than in nonalbinos 5 h before ovulation (P < 0.05). These data suggest that increased egg production of albino hens is associated with differences in P4 and E2 metabolism.

Ovarian morphology and follicular development in sex-linked imperfect albino (s(al)-s) and nonalbino hens before or after a forced moult

1. The effects of the s(al-s) gene on ovarian morphology and the development of ovarian follicles in old laying hens before and after a forced moult were investigated by measuring and weighing the ovaries and follicles. 2. The laying rate of albinos was higher than that of nonalbinos before the forced moult but not afterwards. Hierarchical follicles in albino hens were smaller than those of nonalbinos before but not after the moult. 3. Growth intensity of hierarchical follicles was greater in albino hens before the moult, suggesting that follicular maturation was more rapid, possibly explaining the higher egg production observed. 4. All differences between genotypes disappeared after the moult, suggesting that the state of the ovary before a moult is independent of that afterwards.

Effets des tensions sinusoïdales normales et des trains d'impulsions sur le comportement et la production des poules pondeuses

The effects of normal sinusoidal electrical voltages and impulses on laying hens between 23 and 48 wk of age were evaluated. One hundred and twenty hens were caged individually in six blocks of 20 animals each. Within each block, the treatments were distributed in a randomized complete blocks design. Electrical voltages of constant amplitude of 0–3 V, 4–6 V and 7–9 V were applied in exp. 1, 2 and 3, respectively. Voltage differences with random amplitudes of 0–9 V were applied at a frequency of one pulse every 10 s in exp. 4 and a frequency of two pulses every 10 s in exp. 5. In exp. 6, the hens were subjected to voltages of 12–18 V at a frequency of one pulse every 10 s. In exp. 7, hens were placed three per cage and received either 0 or 12 V with one pulse every 10 s. All voltages were applied between the metallic nipple drinker and the metallic cage. Daily water and feed intake, laying rate and behavior of the hens were measured. These voltages did not affect feed or water consumption, laying rate or egg quality. Frequency of eating and drinking behavior, time spent eating and drinking and time spent standing or sitting were not affected by the treatment. Although poor performance of farm animals is occasionally attributed to stray electrical voltages, in this experiment, voltage differences as high as 18 V had no effect on the hens' production and behavior. Key words: Laying hens, stray voltage, behavior, production performance

Impact of magnetic resonance imaging on the diagnosis of abdominal complications of paroxysmal nocturnal hemoglobinuria

Magnetic resonance (MR) imaging is a method of choice for assessing vascular patency and parenchymal iron overload. During the course of paroxysmal nocturnal hemoglobinuria (PNH), it is clinically relevant to differentiate abdominal vein thrombosis from hemolytic attacks. Furthermore, the study of the parenchymal MR signal intensity adds informations about the iron storage in kidneys, liver, and spleen. Twelve PNH patients had 14 MR examinations of the abdomen with spin-echo T1- and T2-weighted images and flow-sensitive gradient echo images. Vessels patency and parenchymal signal abnormalities--either focal or diffuse--were assessed. MR imaging showed acute complications including hepatic vein obstruction in five patients, portal vein thrombosis in two patients, splenic infarct in one patient. In one patient treated with androgens, hepatocellular adenomas were shown. Parenchymal iron overload was present in the renal cortex of eleven patients with previous hemolytic attacks. On the first MR study of the remaining patient with an acute abdominal pain showing PNH, no iron overload was present in the renal cortex. Follow-up MR imaging showed the onset of renal cortex iron overload related to multiple hemolytic attacks. Despite the fact that all our patients were transfused, normal signal intensity of both liver and spleen was observed in three of them. MR imaging is particularly helpful for the diagnosis of abdominal complications of PNH.

Nutritional change and economic crisis in an urban Congolese community

BACKGROUND

In 1986, the government of Congo undertook a structural adjustment programme to cope with the economic crisis. We present the results of a study whose objectives were to assess the evolution of nutritional status of an urban community between 1986 and 1991 and to identify specific groups for which the nutritional status may have worsened.

METHODS

Two cross-sectional surveys were carried out on representative samples of Brazzaville children < 6 years old: 2295 children were surveyed in 1986 and 2373 in 1991. Anthropometric assessment of nutritional status was performed. For children, weight-for-height and height-for-age indices were used according to WHO recommendations. Wasting and stunting were respectively defined as indices under -2 z-scores. Body mass index of mothers was calculated and risk of chronic energy deficiency (CED) was defined as < 18.5 kg/m2. Socioeconomic data relative to the households were also collected. Multivariate statistical methods were used to obtain adjusted estimates of nutritional changes in the community.

RESULTS

Data analysis led to several converging results: increase in the percentage of low birthweight (10.2% in 1985 versus 18.7% in 1990), increase in the percentage of CED (from 7.9% to 10.5%), and increase in the prevalence of wasting (from 2.9% to 4.2%). By contrast, the overall prevalence of stunting decreased from 13.9% to 11.0%. After statistical adjustment, the factors found to influence the evolution of anthropometric status were: age of child, age of mother, schooling of mother and household characteristics such as number of preschool children, economic level and head of household's occupation.

CONCLUSIONS

The study enables the negative effects of the economic crisis to be quantified. Body mass index is shown to be sensitive to economic changes. It could be recommended as a possible indicator for monitoring the nutritional status at population level. The results also call for a new impetus in preventive health programmes and the implementation of nutritional surveillance activities.

Production and quality of eggs from sex-linked imperfect albino (sal-s) and nonalbino (s+) hens kept under commercial conditions

The beneficial effects of the gene for imperfect albinism on egg production were investigated under commercial conditions. In one line (Line 8) but not in another (Line 3), hen-day egg production of albinos from 46 to 75 wk of age was higher than that of nonalbinos (76.1 vs 72.6%) resulting in higher overall hen-day (71.1 vs 69.3%, P < .08) and hen-housed (276.3 vs 263.6 eggs) egg production by albino hens. Egg production of Line 8 albinos was not different than that of one of two commercial strains (Strain A) included as a control (76.1 vs 75.6%, P > .05). In data from Lines 3 and 8 combined, sexual maturity of albinos was delayed by 3.0 d. Mortality was higher for albinos than nonalbinos (3.6 vs 1.8%) during the first 2 wk of brooding and lower for albinos (5.8 vs 8.9%) during the laying period. Eggs from albinos weighed less (53.8 vs 55.3 g), had smaller yolks (16.9 vs 17.6 g) and shells (5.16 vs 5.27 g), and firmer albumen (5.9 vs 5.6 mm). The results suggest that the gene produces beneficial effects on egg production under commercial conditions.

[Blood lactate in the steeplechase horse: triangular and rectangular series of steps during short duration races]

Five steeplechase race horses were observed during incremental and constant-load exercises with the aim of separating effects of work rate and time on blood lactate. Each independent exercise (an incremental and three constant load tests) was a sequence of three two-minute runs, separated by two one-minute rest intervals for jugular blood sampling. The following observations were made: 1. During constant load exercises, in the five horses, blood lactate stabilized below 4 mmol.l-1: lactatemia critical velocity (LVC) = 3.33 +/- 0.16 mmol.l-1. Nevertheless, VCL, critical lactate velocity inducing LVC, was not statistically different from VS4, velocity inducing a 4 mmol.l-1 blood lactate during incremental tests. Remaining reticent on the meaning of "lactate threshold" often attributed to VS4, an incremental exercise thus seemed pertinent for routine long-term surveys of endurance. 2. If delta L is the blood lactate increase within a single short run, delta L increases linearly with running velocity for an incremental test, allowing the calculation of a "null" velocity, the highest velocity for which there is no significant lactate increase. For independent runs, delta L increased exponentially with velocity, with noticeable differences between horses. This individual short-term functional adaptation variability could be considered in assessment and follow-up of race horse fitness.