Mitral cell temporal response patterns evoked by odor mixtures in the rat olfactory bulb

Mammals generally have the ability to extract odor information contained in complex mixtures of molecular components. However, odor mixture processing has been studied electrophysiologically only in insects, crustaceans, and fish. As a first step toward a better understanding of this processing in high vertebrates, we studied the representation of odor mixtures in the rat olfactory bulb, i.e., the second-order level of the olfactory pathways. We compared the single-unit responses of mitral cells, the main cells of the olfactory bulb, to pure odors and to their binary mixtures. Eighty-six mitral cells were recorded in anesthetized freely breathing rats stimulated with five odorants and their 10 binary mixtures. The spontaneous activity and the odor-evoked responses were characterized by their temporal distribution of activity along the respiratory cycle, i.e., by cycle-triggered histograms. Ninety percent of the mixtures were found to evoke a response when at least one of their two components evoked a response. Mixture-evoked patterns were analyzed to describe the modalities of the combination of patterns evoked by the two components. In most of the cases, the mixture pattern was closely similar to one of the component patterns. This dominance of a component over the other one was related to the responsiveness of the cell to the individual components of the mixture, to the molecular nature of the stimulus, and to the coarse shape of individual response patterns. This suggests that the components of binary mixtures may be encoded simultaneously by different odor-specific temporal distributions of activity.     

In vivo biocompatibility of dextran-based hydrogels

Dextran-based hydrogels were obtained by polymerization of aqueous solutions of methacrylated dextran (dex-MA) or lactate-hydroxyethyl methacrylate-derivatized dextran (dex-lactate-HEMA). Both nondegradable dex-MA and degradable dex-lactate-HEMA disk-shaped hydrogels, varying in initial water content and degree of substitution (DS, the number of methacrylate groups per 100 glucose units), were implanted subcutaneously in rats. The tissue reaction was evaluated over a period of 6 weeks. The initial foreign-body reaction to the dex-MA hydrogels was characterized by infiltration of granulocytes and macrophages and the formation of fibrin, and exudate, as well as new blood vessels. This reaction depended on the initial water content as well as on the DS of the hydrogel and decreased within 10 days. The mildest tissue response was observed for the gel with the highest water content and intermediate DS. At day 21 all dex-MA hydrogels were surrounded by a fibrous capsule and no toxic effects on the surrounding tissue were found. No signs of degradation were observed. The initial foreign-body reaction to the degradable dex-lactate-HEMA hydrogels was less severe compared with the dex-MA gels. In general, the size of the dex-lactate-HEMA hydrogels increased progressively with time and finally the gels completely dissolved. Degradation of the dex-lactate-HEMA hydrogels was associated with infiltration of macrophages and the formation of giant cells, both of which phagocytosed pieces of the hydrogel. A good correlation between the in vitro and the in vivo degradation time was found. This suggests that extra-cellular degradation is not caused by enzymes but depends only on hydrolysis of the ester and/or carbonate bonds present in the crosslinks of the hydrogels. After 21 days, the degradable hydrogels, as such, could not be retrieved, but accumulation of macrophages and giant cells was observed, both of which contained particles of the gels intracellularly. As for the dex-MA hydrogels, no toxic effects on the surrounding tissue were found. The results presented in this study demonstrate that dextran-based hydrogels can be considered as biocompatible materials, making these hydrogels attractive systems for drug delivery purposes.     

Brain stem infarction, systemic lupus erythematosus and circulating lupus anticoagulant

A 30 year old man admitted with a brain stem infarct presented with intellectual deterioration. A diagnosis of systemic lupus erythematosus (S.L.E.) was based on the presence of five A.R.A. criteria :photosensitivity, arthralgia, leukopenia and thrombopenia, false positive syphilitic serology, antinuclear factors on immunofluorescence. A lupus type circulating anticoagulant (L.C.A.) was no longer detected after corticotherapy. This appears to be a case of the "hematologic" form of S.L.E. in which the presence of L.C.A. predisposes towards thrombosis, not only of veins--which is typical--but also of arteries. These may be isolated and reveal the underlying disease as in the present case. The L.C.A. is an antibody possessing antiphospholipid specificity which explains the anticoagulant action in vitro and the thrombogenic effect in vivo. Some authors consider this to be sufficient justification for administration of anticoagulants and/or antiplatelet agents, but corticotherapy may be effective.     

Soccer injuries of youth.

During a soccer tournament with participation of 6,600 boys and girls (9-19 years) all injuries were evaluated, 5.2% of the players were injured; out of these 51% had "slight injuries", 42% "moderate injuries" and 7% "severe injuries". For the individual player the incidence of injury was 19.1/1,000 playing hours including all degrees of injuries; if "slight injuries" were excluded the incidence was 9.4/1,000 playing hours. The incidence rose with increasing age, girls were injured more often than boys. There were 81% of all injuries localised to the lower extremity, especially the ankle and foot. Contusion was the most frequent diagnosis, amounting to a third of all injuries. Blisters and exoriations amounted to nearly a fifth, 4% of the injuries were fractures, especially in the upper extremity; overuse injuries were seen only in 5.2% of the cases. Based on examination of the injury pattern in these children, injuries of youth seem to be relatively rare and mostly of a non-severe character.     

Clinical phobias and avoidant personality disorder among alcoholics admitted to an alcoholism rehabilitation setting

One hundred seventy-three abstinent patients were screened for phobias and avoidant personality disorder. Ninety-six patients were interviewed and diagnosed by two independent assessors who were in agreement on 74% of the diagnoses. In DSM-III terms, over half of the sample (51.4%) met criteria for agoraphobia (8.5%), social phobia (7.8%) and avoidant personality disorder (35.1%). More than 70% of the patients in each diagnostic category were men. For the vast majority of the patients in the sample the disorder preceded the abuse of alcohol which was used by at least 40% of them to relieve their distress in the past. For many it had still a moderating effect on distress at the present but appeared to be mainly used out of "psychological dependence".     

Immediate repair of urethroperineal fistulas after abdominoperineal amputation by means of a cutaneo-muscular flap of the gluteus maximus. Apropos of 2 successfully treated cases

Although a rare complication, the development of a urethro-perineal urinary fistula immediately after abdomino-perineal amputation is a difficult problem to solve. The fragility of the membranous urethra immediately in contact with the exenterated pelvic cavity which takes several weeks to fill in makes any attempt at isolated direct suture very hazardous. Secondary repair is also frequently difficult and the "functional prognosis is far from being always favourable". The major handicap resulting from the perpetuation of this type of fistula has led us to propose an attempt at immediate repair as soon as it is diagnosed with filling of the pelvi-perineal cavity by a cutaneo-muscular flap taken from gluteus maximus. In the two cases in which this treatment was performed, the fistula was cured and a good quality functional result was obtained.     

Hepatic hemobilia: Hemorrhage from the intrahepatic biliary tract,a review

Hepatic hemobilia is defined as hemorrhage arising from pathological changes in the intrahepatic biliary tract. The main causes are iatrogenic trauma, cholangitis, tumors, and coagulopathy. The salient features of the hemobilia syndrome are described and their causes explained. The treatment, when necessitated by hemorrhage or clot formation, is either resection of the liver or occlusion of the responsible artery by ligature or embolization. The iatrogenic trauma may be operative, resulting from instrumental lesion of the bile ducts, needle biopsy, transhepatic cholangiography, biliary tract prosthesis, or inlaying hepatic artery catheters. Among the inflammatory etiologies, special attention is given to nematodes in the ducts, the tropical hemobilia. Spontaneous hemobilia may, just as nose bleeds or hematuria, result from treatment with anticoagulants.

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Résumé L'hémobilie d'origine hépatique répond à l'hémorragie qui provient de lésions situées au niveau des voies biliaires intra-hépatiques. Les causes principales en sont le traumatisme, l'angiocholite, les tumeurs et les troubles de la coagulation. Les caracteres saillants de l'hémobilie sont décrits ainsi que ses causes. Le traitement quand il devient nécessaire en raison de l'importance de l'hémorragie ou de la formation de caillots consiste à réséquer une partie du parenchyme hépatique ou à obtenir l'occlusion de la plaie vasculaire par ligature ou par embolisation.Le traumatisme peut être d'origine iatrogène, qu'il soit le fait d'une lésion instrumentale des canaux biliaires hépatiques, d'une biopsie du foie à l'aiguille, de la cholangiographie transhépatique, ou encore de la présence d'une prothèse au niveau des voies biliaires ou d'un cathéter artériel.Parmi les causes inflammatoires une attention spéciale doit être accordée à l'existence de nématodes au niveau des canaux biliaires intra-hépatiques qui sont à l'origine de l'hémobilie tropicale.L'hémobilie spontanée, comme l'épistaxis ou l'hématurie, peut être la conséquence d'un traitement anti-coagulant.ResumenLa hemobilia hepática se define como hemorragia proveniente de alteraciones patológicas en el tracto biliar intrahepatico. Las causas principales son el trauma iatrogénico, la colangitis, los tumores y la coagulopatía. Se describen las características sobresalientes del síndrome de hemobilia y se explican sus causas. El tratamiento, cuando se hace necesario por hemorragia o por formación de coágulos, es la resección del hígado o la oclusión de la arteria responsable por ligadura o por embolización. El trauma iatrogénico puede ser de origen operatorio, como resultado de lesión instrumental de los canales biliares, biopsia por aguja, colangiografía transhepática, prótesis en el tracto biliar y catéteres colocados en la arteria hepática. Entre las etiologías de naturaleza inflamatoria se presta atención especial a la presencia de nemátodos en los canales, la hemobilia tropical. Al igual de lo que ocurre con las epistaxis o las hematurias, la hemobilia espontanea puede ser consecuencia de tratamientos con anticoagulantes.

     

Detection of cod (Gadus morhua) subpopulations by chemical and statistical analysis of pollutants

The hypothesis was postulated that various subpopulations may be represented in samples of fish living in an open fjord system. A statistical model based on mercury and octachlorostyrene concentrations in cod from two monitoring programs in a Norwegian fjord, was applied to test the hypothesis. The model was (mercury concentration) = b · (weight), where the coefficient b reflects the mercury concentration in the environment and to is the weight exponent. The effects of weight, time, and sex were considered. The distributions of b values, or normalized b values, were investigated by the normal plot technique. Discontinuities in the graphs were interpreted as indicative of the presence of two subpopulations. Weight-independent concentration ratios were also used in the classification of the fish on the octachlorostyrene data. The two subgroups were the same as those revealed by the mercury data. The statistical analysis of mercury and octachlorostyrene data supported the hypothesis that different subpopulations may be represented in samples of fish found in the present and similar fiord systems. The size of a fish sample must permit the testing of a general hypothesis of nonuniform distribution of concentrations of pollutants in the fish.     

Dietary Patterns During Pregnancy and Their Association with Gestational Weight Gain and Anthropometric Measurements at Birth

Maternal and Child Health Journal - Dietary patterns can influence maternal and child health outcomes. The study aims to characterize dietary patterns during pregnancy as well as to identify their...