Apendicitis aguda en la infancia. Factores asociados al retraso diagnóstico / Acute appendicitis in childhood. Factors associated to diagnostic delay

Objetivo: Establecer si existen diferencias clínicas, analíticas y de estudios de imagen en los niños diagnosticados de apendicitis, en la segunda o sucesivas consultas, respecto a los diagnosticados en su primera consulta, en nuestro servicio de urgencias. Método: Estudio retrospectivo de las historias clínicas de los 252 niños con diagnóstico anatomopatológico de apendicitis, durante los años 1999 y 2000. Se clasificaron los pacientes en 2 grupos. Los diagnosticados en su primera consulta (A), versus los que lo fueron en la segunda o sucesivas (B). Resultados: De los 252 niños diagnosticados de apendicitis, 38 (15%) habían consultado previamente en el mismo episodio. Los diagnósticos al alta en esa primera consulta fueron: Dolor abdominal inespecífico (26), diarrea (9), vómitos (2), adenitis mesentérica (1). Se encontraron diferencias significativas en el tiempo de evolución de los síntomas en su primera consulta en urgencias, A (26,84 ± 32,11 horas) versus B (11,31 ± 7,28 horas); edad media, A (114,07 ± 35,63 meses) versus B (98,24 ± 40,5 meses); presencia de diarrea, A (15; 7%) versus B ( 8; 23,6%); presencia de dolor localizado en fosa ilíaca derecha, A (144; 67%) versus B (12; 31%) y exploración física sugestiva, A (138; 64%) versus B (5; 13%). También en el número de pruebas radiológicas realizadas hubo diferencias significativas. Se realizó Rx de abdomen a 200 niños del grupo A (93%) versus 14 del grupo B (37%); ecografía abdominal a 89 niños del grupo A (42%) versus 7 del B (21%). Dentro de las pruebas analíticas se encontró diferencia significativa en el valor de la proteína C reactiva, grupo A (5,01 ± 7,2 mg/dl), versus grupo B (2,2 ± 2,3 mg/dl). En el grupo A hubo 70 (33%) apendicitis perforadas versus 25 (66%) en el B. La media de días de hospitalización fue de 5,75 ± 3,9 para el grupo A versus 7,84 ± 5,5 para el B, siendo también una diferencia significativa. No se encontraron diferencias entre los dos grupos en la presencia de fiebre, vómitos ni leucocitosis. Conclusiones: El retraso en el diagnóstico en la apendicitis aguda se asocia a: un aumento del número de apendicitis perforadas, con el consiguiente incremento de la morbi-mortalidad y aumento de días de hospitalización. Los errores diagnósticos en la primera consulta en urgencias se deben sobre todo al menor tiempo de evolución de los síntomas. También influyen la presencia de síntomas inespecíficos como la diarrea y la menor edad de los pacientes. Las pruebas diagnósticas tienen un escaso valor en los casos poco evolucionados (AU)

Aim: To assess whether clinical, analytical and/or image studies differences do exist among children with a diagnosis of appendicitis in second or successive visits as compared to those diagnosed on the first visit in our Emergency Outpatient Ward. Methods: Retrospective study of the clinical records of 252 children with an anatomopathological diagnosis of appendicitis between 1999 and 2000. Patients were classified into two groups: those diagnosed during the first visit (A), versus those diagnosed in the second or successive visits (B). Results: From among the 252 children with a diagnosis of appendicitis, 38 (15%) had a previous consultation during the same episode. The discharge diagnoses upon that first visit (consultation) were “non-specific abdominal pain” (n = 26), “diarrhoea” (n = 9), “vomiting” (n = 2) and “mesenteric adenitis” (n = 1). Statistically significant differences were seen in a number of criteria: period of evolution of symptoms upon the first Outpatient Emergency Ward consultation (A, 26.84 ± 32.11 hours; B, 11.31 ± 7.28 hours), mean age (A, 114.07 ± 35.63 months; B, 98.24 ± 40.5 months), presence of diarrhoea (A, n = 15, 7%; B, n = 8, 23.6%), presence of right iliac fossa pain (A, n = 144, 67%; B, n = 12, 31%), and suggestive physical examination (A, n = 138, 64%; B, n = 5, 13%). There were also significant differences in the number of radiologic examinations performed: a plain film of the abdomen was carried out in 200 children in group A (93%) versus 14 in group B (37%), and abdominal ultrasound scans were carried out in 89 children in group A (42%) versus 7 in group B (21%). Among the laboratory tests, a significant difference was observed in the C-reactive protein level: 5.01 ± 7.2 mg/dl in group A, versus 2.2 ± 2.3 mg/dl in group B. There were 70 cases of perforated appendicitis (33%) in group A versus 25 (66%) in group B. The mean duration of hospital admission was 5.75 ± 3.9 days for group A and 7.84 ± 5.5 days for group B (also a statistically significant difference). There were no inter- group differences in presence of vomiting, fever or leukocytosis. Conclusions: The delay in diagnosis of acute appendicitis is associated to an increase in the number of perforated appendicitides, with the subsequent increase in morbi-mortality and in the duration of hospital admission. Diagnostic errors on the first consultation at the Outpatient Emergency Ward were mainly due to the shorter period of symptom evolution. The presence of nonspecific symptoms such as diarrhoea and the shorter age of the patients also have an influence. The diagnostic tests are of little value in cases with a short evolution (AU)

[Diagnostic yield of abdominal ultrasonography in acute appendicitis]. / Rendimiento de la ecografía abdominal en el diagnóstico de apendicitis aguda.

INTRODUCTION: Acute appendicitis (AA) is the first cause of surgical abdomen in childhood but diagnosis continues to be difficult in some cases. Abdominal ultrasonography has been shown to be useful when there is doubt about the diagnosis and can be quickly and easily performed at the patient's bedside. OBJECTIVE: To evaluate the efficacy of abdominal ultrasonography in the diagnosis of acute appendicitis in our hospital. PATIENTS AND METHODS: All patients who visited the emergency department for abdominal pain and who underwent abdominal ultrasonography to rule out AA between January 1, 1999 and December 31, 2000 were retrospectively studied. RESULTS: During the study period, 4217 children were evaluated in our service for abdominal pain. Ultrasonography was performed in 528 children. Of these, the procedure was performed to rule out AA in 308 patients. Of these 308 patients who met the study's inclusion criteria, the results of ultrasonography were compatible with AA in 102 and were normal in 196. Ultrasonographic diagnosis differed from the final diagnosis in 16 patients. In eight children with ultrasonographic findings suggestive of AA, laparotomy revealed normal appendices. In the remaining eight patients, ultrasonographic findings were normal and surgery revealed AA. Based on these findings, the diagnostic yield of abdominal ultrasonography was: sensitivity: 96.6 %; specificity: 95.9 %, positive predictive value: 86 %; negative predictive value: 95.9 %. CONCLUSIONS: The overall diagnostic yield of abdominal ultrasonography in AA our hospital is acceptable. Because ultrasonographic diagnosis is not always accurate, others diagnostic methods such as computed tomography should be used in doubtful cases.

Rendimiento de la ecografía abdominal en el diagnóstico de apendicitis aguda / Diagnosticyield of abdominal ultrasonography in acute appendicitis

Introducción. Aunque la apendicitis aguda es la primera causa de abdomen agudo en la infancia, el diagnóstico continúa siendo difícil en algunas ocasiones. En los casos en que existan dudas diagnósticas la ecografía abdominal es una herramienta útil, de rápida realización y accesible en la cabecera del enfermo. Objetivo. Evaluar la eficacia en nuestro medio de la ecografía abdominal para el diagnóstico de apendicitis aguda. Pacientes y métodos. Estudio retrospectivo, entre el 1 de enero de 1999 y el 31 de diciembre de 2000, de todas las consultas en el servicio de urgencias por dolor abdominal indicativo de abdomen agudo, en los que se realizó una ecografía abdominal para descartar apendicitis aguda. Resultados. Consultaron en nuestro servicio 4.217 niños por dolor abdominal. Se realizó ecografía en 528 niños. De éstos, en 308 niños la exploración ecográfica se llevó a cabo para descartar el diagnóstico de apendicitis aguda. De los 308 pacientes que reunieron los criterios de inclusión en el estudio, en 112 ocasiones la ecografía fue indicativa de apendicitis aguda y en 196, normal. En 16 pacientes el diagnóstico ecográfico fue discordante con el diagnóstico final. En 8 pacientes el informe ecográfico de apendicitis y laparotomía en blanco. Los otros 8 niños restantes con ecografía informada como normal y diagnóstico quirúrgico de apendicitis aguda. Con estos datos, el rendimiento global de la ecografía para el diagnóstico de apendicitis aguda que se obtuvo en el presente estudio se tradujo en una sensibilidad del 96,6 por ciento, especificidad del 95,9 por ciento, un valor predictivo positivo del 86 por ciento y un valor predictivo negativo del 95,9 por ciento. Conclusiones. El rendimiento global de la ecografía abdominal para el diagnóstico de apendicitis aguda en nuestro medio es aceptable. La presencia de falsos positivos y negativos, aunque mínima, obliga a valorar la utilización de otras pruebas diagnósticas (tomografía computarizada) en los casos dudosos (AU)

Central vasotocin-immunoreactive system in a male passerine bird (Junco hyemalis).

Previous investigations have identified regions of the avian brain that contain immunoreactive vasotocinergic (VT-ir) cell bodies and fibers. These studies exclusively used domesticated species, and the relevance of the findings for free-living birds has not been established. The present study used immunocytochemistry to determine the neuroanatomical distribution of the VT-ir system in the brain of a well-studied male passerine bird (dark-eyed junco, Junco hyemalis) obtained from a natural population in interior Alaska (65 degrees N, 147 degrees W). VT-ir cell bodies were observed in several brain regions (paraventricular and supraoptic nuclei, nucleus of the stria terminalis), where they have been described in other oscine species. VT-ir fibers were widespread in many brain regions and were especially abundant in the medial preoptic nucleus, the basal region of the septum, and the hypothalamic-neurohypophyseal tract. Fibers were also present in brain regions that are involved in the control of vocal behavior including the ventromedial capsular region of the nucleus robustus archistriatalis and the dorsomedial portion of the mesencephalic nucleus intercollicularis. The widespread brain distribution of VT-ir cell bodies and fibers in juncos generally resembles that of domestic birds and suggests a role for this neuropeptide in the control of reproductive behavior and physiology.

Calretinin immunoreactivity in the anterior olfactory nucleus of the rat.

Calretinin-immunoreactive structures in the anterior olfactory nucleus of the rat were studied using a polyclonal antibody, which does not cross-react with the highly homologous calcium-binding protein calbindin-D28k, and the avidin-biotin-peroxidase technique. Calretinin-immunopositive neurons were found in all regions of the anterior olfactory nucleus, with the highest number in the medial subdivision and dorsal transition area. The immunostained neurons, although morphologically heterogeneous, demonstrated typically small size. In addition to neuronal somata, calretinin-immunopositive fibres and terminals, some of them forming basket-like arrangements surrounding immunonegative neurons, were observed. Although calretinin and calbindin-D28k colocalize in several brain regions, and both proteins showed an extensive overlap in the anterior olfactory nucleus, immunostained semithin sections demonstrated that calretinin does not co-localize with calbindin-D28k in this nucleus.

McAB 300 antibody against calbindin D-28K is a glial marker in the teleost brain.

The monoclonal antibody McAB 300 against calbindin D-28 k demonstrated an immunostaining pattern in the teleost brain completely different to those obtained in other classes of vertebrates, or after using in the teleost brain other monoclonal and polyclonal antibodies raised against the same protein. Although calbindin D-28k is considered a neuronal marker, McAB 300 specifically stained glial cells throughout the brains of teleosts, with the only exception of some retinal amacrine and horizontal cells.

Calretinin- and parvalbumin-immunoreactive neurons in the rat main olfactory bulb do not express NADPH-diaphorase activity.

The presence of nitric oxide synthase (NOS) in neuronal elements expressing the calcium-binding proteins calretinin (CR) and parvalbumin (PV) was studied in the rat main olfactory bulb. CR and PV were detected by using immunocytochemistry and the nitric oxide (NO) -synthesizing cells were identified by means of the reduced nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-diaphorase) direct histochemical method. The possible coexistence of NADPH-diaphorase and each calcium-binding protein marker was determined by sequential histochemical-immunohistochemical double-labeling of the same sections. Specific neuronal populations were positive for these three markers. A subpopulation of olfactory fibers and olfactory glomeruli were positive for either NADPH-diaphorase or CR. In the most superficial layers, groups of juxtaglomerular cells, superficial short-axon cells and Van Gehuchten cells demonstrated staining for all three markers. In the deep regions, abundant granule cells were NADPH-diaphorase- and CR-positive and a few were PV-immunoreactive. Scarce deep short-axon cells demonstrated either CR-, PV-, or NADPH-diaphorase staining. Among all these labeled elements, no neuron expressing CR or PV colocalized NADPH-diaphorase staining. The present data contribute to a more detailed classification of the chemically- and morphologically-defined neuronal types in the rodent olfactory bulb. The neurochemical differences support the existence of physiologically distinct groups within morphologically homogeneous populations. Each of these groups would be involved in different modulatory mechanisms of the olfactory information. In addition, the absence of CR and PV in neuronal groups displaying NADPH-diaphorase, which moreover are calmodulin-negative, indicate that the regulation of NOS activity in calmodulin-negative neurons of the rat olfactory bulb is not mediated by CR or PV.

Transient expression of NADPH-diaphorase/nitric oxide synthase in the paratenial nucleus of the rat thalamus.

The distribution pattern of nitric oxide synthesizing neurons was studied in the paratenial nucleus throughout the rat development using the NADPH-diaphorase (ND) histochemical method and nitric oxide synthase (NOS) immunocytochemistry. The onset of ND/NOS activity in the paratenial nucleus was detected in the postnatal life day 1. Until the postnatal stage 4, a quick increase in the number and staining intensity of the ND/NOS positive neurons was observed. From postnatal day 4 to postnatal day 6, these variations continued slowly, whereas an increase in the neuronal size was evident. In these stages, densely packed ND/NOS-labeled neurons were observed. From stages 6 to 10, the ND/NOS-positive elements demonstrated similar number, size, and staining intensity. These cells had medium size, variable morphology and showed reaction product in the cell bodies and, at most, their proximal dendrites. After postnatal day 10, a quick decrease in the staining intensity and in the number of ND/NOS-labeled elements was detected, although no changes were observed in their morphological characteristics. Postnatal day 15 was the last developmental stage studied in which ND/NOS-positive elements were observed. Finally, the paratenial nucleus did not present ND/NOS-positive elements in adult animals. This transient expression of the ND/NOS-activity suggests a role of nitric oxide in the reorganization of the paratenial nucleus during the first postnatal fortnight.

Coexistence of NADPH-diaphorase and tyrosine hydroxylase in the mesencephalic catecholaminergic system of the Japanese quail.

Previous studies have shown the presence of a large number of tyrosine hydroxylase immunoreactive neurons and nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase positive elements within the mesencephalic and pontine regions of the Japanese quail. In the present study histochemical and immunohistochemical procedures reveal that cells expressing at least one of these two neurochemical markers coexist throughout a large part of the substantia nigra and of the area ventralis of Tsai. Also about 40% of the neurons in these two regions that contain immunoreactive tyrosine hydroxylase also exhibit NADPH-diaphorase activity. This is not a general property of the quail catecholaminergic system: in the locus coeruleus (the main noradrenergic group) there is a complete separation between these two neuronal populations. The number of neurons expressing either neurochemical marker is not different between males and females in any of the regions that have been investigated. NADPH-diaphorase is known to be an indicator of the enzyme nitric oxide synthase; these results therefore suggest that nitric oxide may play an important role in the regulation of the activity of a significant part of the avian mesencephalic dopaminergic system.

Testosterone effects on vasotocinergic innervation of sexually dimorphic medial preoptic nucleus and lateral septum during aging in male quail.

Vasotocin fibers are known to innervate regions important in the regulation of sexual behavior and neuroendocrine systems in quail. In this experiment, vasotocinergic innervation of the lateral septum and of the sexually dimorphic medial preoptic nucleus was studied during reproductive aging relative to sexual behavior or following testosterone (T). There were 4 groups of male Japanese quail (Coturnix japonica) studied: adult reproductive (6 month, n = 4), photoregressed adult (n = 5), old senescent (36 month, n = 4), and old testosterone-treated (n = 5). Immunocytochemistry for vasotocin (VT) was performed on serial sections and quantification of the density of VT-positive fibers was performed by image analysis. Results showed a highly significant decrease in VT-immunocytochemical staining in photoregressed and in old senescent males; whereas T-treatment in old males was associated with recovery of VT-immunocyto-chemical staining, comparable to the adult reproductive male. Previous experiments have shown that T treatment restimulates sexual behavior in senescent males similar to the recovery of sexual behavior in T-treated castrates. These results indicate that the VT system may be associated with the behavioral recovery observed in senescent T-treated males.

Calbindin D-28k immunoreactivity in the rat accessory olfactory bulb.

The distribution pattern and the morphology of calbindin D-28k-immunoreactive neurons were studied in the accessory olfactory bulb of the rat using a monoclonal antibody and the avidin-biotin-immunoperoxidase method. Positive neurons were observed in all layers but the vomeronasal nerve layer. Scarce mono-dendritic periglomerular neurons were calbindin D-28k-immunoreactive. Different morphological types of short-axon cells were calbindin D-28k-immunostained, with different degrees of intensity, in the boundary between the internal and external plexiform layer. In addition, deep short-axon cells located in the granule cell layer were calbindin D-28k-immunopositive. By contrast, previous studies described all cells in the rat accessory olfactory bulb as calbindin D-28k-immunonegative. The staining pattern in the rat accessory olfactory bulb showed both similarities and differences with the distribution pattern of the same calcium-binding protein in the main olfactory bulb.

NADPH-diaphorase in the central nervous system of the tench (Tinca tinca L., 1758).

The distribution and morphological characterization of nicotinamide adenine dinucleotide phosphate-diaphorase (ND)-positive cells and fibers in the tench central nervous system was mapped by using a direct histochemical method. This enzyme was observed in specific cell populations throughout all main divisions of the tench brain. In the telencephalon, we found strongly labeled olfactory fibers, as well as positive cells and fibers in the area ventralis of the telencephalic lobes. Positive staining was observed in the following diencephalic nuclei: nucleus preopticus magnocellularis pars magnocellularis, nucleus recessus lateralis, nucleus recessus posterioris, nucleus posterior tuberis, and nucleus diffusus torus lateralis, as well as small cells with a diffuse distribution surrounding the diencephalic ventricle. In the mesencephalon, heavily stained ND-positive neurons were observed in the nucleus fasciculi longitudinalis medialis, nucleus nervi oculomotorius, and nucleus nervi trochlearis. In the hindbrain the most evident staining was observed as large neurons located in the nuclei of the cranial nerves, scattered positive cells located between the negative fibers of the cranial nerves, and in the nucleus fasciculi solitari. Finally, in the spinal cord, ND-positive cells and fibers were mainly located in the ventral horn. This distribution of ND labeling in the brain of the tench is significantly different from previous data on ND activity in the brain of terrestrial vertebrates and does not correlate with the presence and distribution patterns of several neurotransmitters and neuroactive substances in the teleost brain.

NADPH-diaphorase active and calbindin D-28k-immunoreactive neurons and fibers in the olfactory bulb of the hedgehog (Erinaceus europaeus).

The hedgehog, a macrosomatic insectivore with an extraordinary development of the olfactory structures, has a crucial value for any phylogenetic or comparative study in mammals. The distribution pattern and morphology of NADPH-diaphorase-active and calbindin D-28k-immunoreactive neurons were studied in the main and accessory olfactory bulbs of the hedgehog. NADPH-diaphorase (ND) staining was carried out by a direct histochemical method, and the calbindin D-28k (CaBP) immunoreaction by using a monoclonal antibody and the avidin-biotin-immunoperoxidase method. The possible coexistence of both markers was determined by sequential histochemical-immunohistochemical double labeling of the same sections. Specific neuronal populations were positive for both ND and CaBP markers. No cell colocalized both stains in the hedgehog olfactory bulb. A subpopulation of olfactory fibers, and a subpopulation of olfactory glomeruli, located on the medial side, were positive for ND. Surrounding both the ND-positive and ND-negative glomeruli, there were ND- and CaBP-positive periglomerular cells, the latter group being much more abundant. A subpopulation of superficial short-axon cells was CaBP positive but, contrary to what is observed in rodents, this neuronal type was always ND negative. In addition, three neuronal types were observed in the GL-EPL border after CaBP immunostaining. These neuronal types have not been previously described either in the hedgehog or in the rodent olfactory bulb. Horizontal cells and vertical cells of Cajal were also observed after both ND and CaBP labeling. Distinct groups of ND- and CaBP-positive cells, differing in size, shape, dendritic branching pattern, and staining intensity, were distinguished in the granule cell layer and in the white matter. The large and medium-sized cells were identified as a very heterogeneous population of deep short-axon cells, whereas a subpopulation of granule cells was ND positive. The accessory olfactory bulb showed ND staining in all vomeronasal fibers and glomeruli, and in subpopulations of periglomerular cells, granule cells, and deep short-axon cells. The CaBP immunolabeling was more restricted and located in subpopulations of periglomerular cells and in deep short-axon cells. These results indicate different and more complex ND and CaBP staining patterns in the hedgehog olfactory bulb than those previously described in rodents, including the presence of specific, chemically and morphologically defined new neuronal types.

Histochemical localization of NADPH-diaphorase in the rat accessory olfactory bulb.

The distribution of NADPH-diaphroase activity was examined in the accessory olfactory bulb of the rat using a direct histochemical technique. Labeled fibers and somata were found in all layers of the accessory olfactory bulb. The entire vomeronasal nerve and all vomeronasal glomeruli were strongly labeled, contrary to the main olfactory bulb, where only dorsomedial olfactory glomeruli displayed NADPH-diaphorase activity. NADPH-diaphorase positive neurons were identified as periglomerular cells in the glomerular layer and external plexiform layer, horizontal cells in the internal plexiform layer, and granule cells and deep short-axon cells in the granule cell layer. The labeled dendrites of the granule cells formed a dense neuropile in the granule cell layer, internal plexiform layer and external plexiform layer. The staining pattern in the accessory olfactory bulb was more complex than what has been previously reported, and demonstrated both similarities and differences with the distribution of NADPH-diaphorase in the main olfactory bulb.

Parvalbumin immunoreactivity in the telencephalic hemispheres of the tench, Tinca tinca.

The distribution of parvalbumin immunoreactivity in the telencephalic hemispheres of the tench (Tinca tinca L.) was studied using a monoclonal antibody and the avidin-biotin immunoperoxidase method. A wide distribution of immunoreactive structures was found in both dorsal and ventral areas of the telencephalic hemispheres. Normally, the parvalbumin-immunostained neurons in the dorsal area were smaller, more weakly stained, and more scattered than those in the ventral one. In the dorsal area, parvalbumin-immunoreactivity was observed in practically all divisions. The highest density of positive somata was found in the lateral nucleus. Density of stained fibres was generally low. Labelling in the ventral area appeared in the ventral and dorsal nuclei, with a high density of both immunoreactive fibres and cell bodies. Neurons were seen close to the ventricle, arranged in two groups of neurons with different sizes and morphologies. The distribution and morphological characteristics of the parvalbuminergic cells were similar to those of previously described GABAergic elements, suggesting a possible colocalization of both substances in the teleost telencephalon, as it has been observed in different telencephalic areas of land vertebrates. On the other hand, significant differences were seen between the distribution of parvalbumin in the telencephalic hemispheres of the tench in comparison with its distribution pattern in supposed homologous structures of the forebrain of amniotes.

Nicotinamide-adenine-dinucleotide-phosphate diaphorase-positive neurons and fibers in the nucleus olfactorius anterior of the rat.

The distribution patterns of NADPH-diaphorase activity in the nucleus olfactorius anterior (NOA) and anterior commissure (AC) of the rat were described using an histochemical technique. In the lateral, dorsal, ventral, medial and posterior subdivisions of the NOA we have demonstrated heavily stained elements (neurons and processes), and slightly labelled cell bodies. The neurons were mainly located in the inner zone of these subdivisions. However, in the external subdivision (NOAe) strongly stained fibers and weakly labelled cell bodies were present. The NOA transitions areas showed the same NADPH-diaphorase activity distribution patterns as those of the corresponding NOA subdivisions. In the AC we described scarce NADPH-diaphorase positive fibers parallelly oriented to the unstained commissural fibers, and scattered stained neurons.

Distribution of calbindin D-28K and parvalbumin immunoreactivities in the nucleus olfactorius anterior of the rat.

The distributions of calbindin D-28K (CaBP) and parvalbumin (PV) in the rat nucleus olfactorius anterior (NOA) were described using monoclonal antibodies and the avidin-biotin-peroxidase method. The NOA showed a high immunoreactivity for CaBP, with a rostrocaudal increase in the positive neurons and fibres. Pars externa (NOAe) was the only subdivision which showed a low CaBP immunostaining. PV-positive elements were less abundant than those CaBP immunostained. The main difference in the distributions for both proteins was observed in the pars medialis which was practically PV negative. PV- and CaBP-stained neurons showed similar morphologies in the subdivisions where they were present. In NOAe, we observed a characteristic PV- and CaBP-positive neuronal type, with an oriented dendritic pattern. Transition areas were clearly observable in both CaBP- and PV-labelled sections.

Calbindin D-28k-positive neurons in the rat olfactory bulb. An immunohistochemical study.

We have studied the distribution of calbindin D-28k immunoreactivity in the rat olfactory bulb using specific monoclonal antibodies and the avidin-biotin-immunoperoxidase method. The largest number of positive neurons was located in the periglomerular layer. These neurons were identified as periglomerular cells; they have been described also by other authors as calbindin-positive elements. Close to these neurons, a second population of nerve cells was identified as superficial short-axon neurons. The remaining layers showed a smaller number of stained elements. Other labeled neurons were located along the external border of the external plexiform layer; the scarce neurons marking its internal border were identified as van Gehuchten cells. No immunoreactive structures were found in the mitral cell layer, although we observed another population of immuno-stained short-axon cells at its internal border. Some reactive structures, identified by us as horizontal and vertical cells of Cajal, were located in the boundary zone between the internal plexiform layer and the granule layer. In the white matter, we found a neuronal type characterized by its large size and oriented arborization of varicose dendrites.

An atlas of the brain of the tench (Tinca tinca L., 1758; Cyprinidae, Teleostei).

This report provides an atlas of the tench brain in the transverse plane. The brain atlas is based on paraffin-embedded brains which are serially sectioned and stained with cresyl violet. It consists of drawings and photographs at several levels throughout the main divisions of the tench brain. The brain of the tench shows important variations in the shape, extension and boundaries of different brain areas and nuclei in comparison with those previously described in the brain of other teleosts.