Assessing the relationship between organic farming practices and microbiological characteristics of organic lettuce varieties (Lactuca sativa L.) grown in Sao Paulo, Brazil.

AIMS: This study aimed to gather information on farming practices employed in organic lettuce fields in Sao Paulo, Brazil and associate these practices with the microbiological characteristics of the products. METHODS AND RESULTS: Practices were surveyed using a questionnaire applied in ten farms, where 200 heads of lettuce were collected and submitted to enumeration of total coliforms and generic Escherichia coli and tested for Salmonella spp. using culture and molecular (qPCR) methods. Based on the responses, the farms could be clustered in two groups: group 1, comprised by six farms, where chicken manure was used as fertilizer in most of them and the composting process was not performed on site; and group 2, comprised by four farms, where other types of fertilizer were used, and the composting process was performed on site. Generic E. coli was detected in 56 (28%) samples, with an average of 1·1 ± 0·7 log MPN per g. Salmonella DNA was detected in two (1%) samples by qPCR. CONCLUSIONS: The prevalence and bacterial loads of generic E. coli, and the occurrence of Salmonella, even at low populations undetectable by conventional culture methods, highlight the need for control measures during farming practices to reduce microbial contamination and risks of foodborne illnesses. These measures include the use of properly composted manure and appropriate washing procedures for leafy vegetables before consumption. SIGNIFICANCE AND IMPACT OF THE STUDY: The obtained data contribute to a better understanding of the farming practices of organically grown lettuces in Sao Paulo, Brazil.

Patterns of impaired internal anal sphincter activity in patients with anal fissure.

AIM: The patterns of impaired internal anal sphincter activity were studied in patients with anal fissure (AF). METHOD: Twenty healthy controls and 61 patients with acute AF were studied, using anorectal manometry with electromyography (EMG), and 53 patients with chronic AF using high-resolution manometry and ultrasonography. Mean and maximal resting anal pressure (MRAP), spontaneous rhythmic slow and ultraslow waves (USW) and relaxation induced by rectal distension were measured. RESULTS: Patients with acute AF had higher mean (106.4 ± 28.1 mmHg) and maximal resting anal pressure (161.5 ± 43.7 mmHg) than those with chronic AF (P < 0.05); 95% of patients had slow waves (SW) and 67% ultraslow waves. Patients with chronic AF had higher mean (92.4 ± 22.6 mmHg) and maximal resting anal pressure (117.5 ± 32.0 mmHg) than controls and 94% of patients had slow waves and 69% ultraslow waves. Patients with ultraslow waves (with either acute or chronic AF) had increased internal sphincter hypertonicity (mean and maximal resting pressure), decreased internal sphincter relaxation and increased after-contraction following rectal distension. CONCLUSIONS: Patients with acute AF had higher hypertonicity than those with chronic AF and both had increased spontaneous rhythmic activity (waves). Patients with AF and ultraslow waves had higher internal anal sphincter hypertonicity and reduced internal sphincter relaxation and enhanced after-contraction following rectal distension.

Projections from the inferior colliculus to the tectal longitudinal column in the rat.

We have used the anterograde tracer Phaseolus vulgaris-leucoagglutinin (PHA-L) to study with albino rats the projections from the inferior colliculus (IC) to the tectal longitudinal column (TLC), a newly discovered nucleus that spans the midbrain tectum longitudinally, on each side of the midbrain, immediately above the periaqueductal gray matter. We studied the projections of the medial IC, which includes the classical central nucleus (CNIC) and the dorsal cortex (DCIC), and those of the lateral IC, equivalent to the classical external cortex (ECIC). Following unilateral injections of PHA-L into the medial IC, numerous terminal fibers are labeled bilaterally in the TLC. The ipsilateral projection is denser and targets the entire nucleus, whereas the contralateral projection targets significantly only the caudal half or two-thirds of the TLC. Fibers from the medial IC reach the TLC by two routes: as collaterals of axons that travel in the commissure of the IC and as collaterals of thick ipsilateral colliculogeniculate axons; the latter travel through the deep superior colliculus on their way to the TLC. Within the TLC, individual IC fibers tend to run longitudinally. The injection of PHA-L into the lateral IC indicates that this subdivision sends a weak, bilateral projection to the TLC whose trajectory, morphology and distribution are similar to those of the projection from the medial IC. These results demonstrate that all subdivisions of the IC send projections to the TLC, suggesting that the IC may be one of the main sources of auditory input to this tectal nucleus.

Connections of the superior paraolivary nucleus of the rat: projections to the inferior colliculus.

GABAergic neurotransmission contributes to shaping the response properties of inferior colliculus (IC) neurons. In rodents, the superior paraolivary nucleus (SPON) is a prominent and well-defined cell group of the superior olivary complex that sends significant but often neglected GABAergic projections to the IC. To investigate the trajectory, distribution and morphology of these projections, we injected the neuroanatomical tracer biotinylated dextran amine into the SPON of albino rats. Our results demonstrate that: (1) the SPON innervates densely all three subdivisions of the ipsilateral IC: central nucleus (CNIC), dorsal cortex (DCIC) and external cortex (ECIC). The SPON also sends a sparse projection to the contralateral DCIC via the commissure of the IC. (2) SPON axons are relatively thick (diameter >1.2 microm), ascend to the midbrain tectum in the medial aspect of the lateral lemniscus, and, for the most part, do not innervate the nuclei of the lateral lemniscus. (3) SPON fibers ramify profusely within the IC and bear abundant en passant and terminal boutons. (4) The axons of neurons in discrete regions of the SPON form two laminar terminal plexuses in the ipsilateral IC: a medial plexus that spans the CNIC and DCIC parallel to the known fibrodendritic laminae of the CNIC, and a lateral plexus located in the ECIC and oriented more or less parallel to the surface of the IC. (5) The projection from SPON to the ipsilateral IC is topographic: medial SPON neurons innervate the ventromedial region of the CNIC and DCIC and the ventrolateral region of the ECIC, whereas more laterally situated SPON neurons innervate more dorsolateral regions of the CNIC and DCIC and more dorsomedial regions of the ECIC. Thus, SPON fibers follow a pattern of distribution within the IC similar to that previously reported for intracollicular and corticocollicular projections.

Colocalization of GABA and glycine in the ventral nucleus of the lateral lemniscus in rat: an in situ hybridization and semiquantitative immunocytochemical study.

We have studied by in situ hybridization for GAD65 mRNA in thick sections and by semiquantitative postembedding immunocytochemistry in consecutive semithin sections, the expression of gamma-aminobutyric acid (GABA) and glycine in cell bodies and axosomatic puncta of the rat ventral nucleus of the lateral lemniscus (VNLL), a prominent monaural brainstem auditory structure. The in situ hybridization and the densitometric analysis of the immunostaining suggest that the rat VNLL contains two main populations of neurons. Approximately one-third of neurons are unstained with either technique and are presumably excitatory; their cell bodies are enveloped by a large number of glycine-immunoreactive puncta. Most if not all of the remaining two-thirds colocalize GABA and glycine and are assumed to be inhibitory. These two populations show a complementary distribution within the VNLL, with inhibitory neurons located mainly ventrally and excitatory neurons dorsally. In scatterplots of gray values measured from cell bodies, the double-labeled cells appear to form a single cluster in terms of their staining intensities for the two transmitter candidates. However, this cluster may have to be further subdivided because cells with extreme GABA/glycine ratios differ from those with average ratios with respect to location or size. The VNLL seems unique among auditory structures by its large number of neurons that colocalize GABA and glycine. Although the functional significance of this colocalization remains unknown, our results suggest that the VNLL exerts convergent excitatory and inhibitory influences over the inferior colliculus, which may underlie the timing processing in the auditory midbrain.

Anisotropic organization of the rat superior paraolivary nucleus.

In rodents, the superior paraolivary nucleus (SPON) is one of the major nuclei of the superior olivary complex that innervate the inferior colliculus. To analyze the intrinsic organization of the SPON and to gain further insight into its relationship with the inferior colliculus, the neuroanatomical tracers biotinylated dextran and horseradish peroxidase were unilaterally injected into different regions of the central nucleus of the inferior colliculus of adult albino rats. Both tracers resulted in retrograde labeling of SPON cell bodies. In addition, biotinylated dextran rendered excellent filling of dendritic and axonal processes within the nucleus. Our results confirm that the projection from the SPON to the central nucleus of the inferior colliculus is nearly exclusively ipsilateral and strictly topographic. Furthermore, our data show that virtually all SPON neurons participate in this projection. The labeling with biotinylated dextran reveals that typical SPON neurons are medium to large multipolar cells with four to seven thick, long, scarcely branched and smooth dendrites that extend over long distances within a nearly parasagittal plane and intermingle with similarly oriented axonal plexuses. Some of the neurons located ventrally within the nucleus possess dendrites that extend ventrally beyond the limits of the SPON to penetrate into the underlying ventral nucleus of the trapezoid body. The parallel arrangement of flattened dendritic and axonal fields within the SPON is reminiscent of the fibrodendritic laminae found in other mammalian auditory nuclei. This fact and the available data about the connectivity of the nucleus stress the similarities between the SPON and the principal nuclei of the superior olivary complex.

Projections of cochlear root neurons, sentinels of the rat auditory pathway.

In certain rodents, the root of the cochlear nerve contains a population of large neurons, known as cochlear root neurons (CRNs), an essential element of the primary acoustic startle pathway. To characterize the projections of the CRNs, we made stereotaxically guided, iontophoretic injections of biotinylated tracers into the cochlear nerve root of albino rats. CRN axons, which are remarkably thick, enter the trapezoid body, cross the midline, and ascend in the rostral aspect of the lateral lemniscus to reach the upper levels of the midbrain. As a group, CRN axons produce a characteristic pattern of profusely ramified collaterals that innervate specific brainstem regions. The main target of CRN axons is the contralateral pontine reticular formation, where collaterals terminate in the caudal pontine reticular nucleus (PnC) and, to a lesser degree, in the ventrolateral tegmental area, the oral pontine reticular nucleus, and the rostral and medial paralemniscal regions. Other targets of CRN axons include the lateral paragigantocellular nucleus of both sides, the ipsilateral facial motor nucleus and PnC, and the contralateral intercollicular tegmentum and superior colliculus. Notably, CRNs apparently do not innervate any of the nuclei of the auditory brainstem, as usually defined, even though their axons pass through or in close proximity to them. The fact that CRNs innervate several reticular and tectal structures that mediate auditory alerting and escape behaviors suggests that they are "early warning neurons," i.e., true sentinels of the auditory pathway.

Cranial vault moulding by the transcutaneous activation of implanted magnets.

The technique of distraction osteogenesis has not been widely used in the treatment of injuries of the head and face because of the need for external fixators. By using magnetic, rather than mechanical, forces to drive bone movement we hope to expand the applications of the technique to include the treatment of cranial vault deformities. Fifteen immature rabbits were studied. When they were 6 weeks old each had a magnet fixed to their left parietal bone. A head frame was attached and a magnet of either the opposite polarity to, (group 1), or the same polarity as, (group 2), the implanted magnet was mounted on the frame. Five weeks later the rabbits were sacrificed. There were significant differences in parietal skull width and in several measures of skull length between the animals in group 1 and those in group 2. These results demonstrate that, in this model, magnetic forces can be used to modify skull growth.

Distribution of descending projections from primary auditory neocortex to inferior colliculus mimics the topography of intracollicular projections.

To ascertain whether the auditory neocortex also innervates the central nucleus of the inferior colliculus (CNIC) and not only its dorsal (DCIC) and external (ECIC) cortices, the anterograde tracers Phaseolus vulgaris-leucoagglutinin (PHA-L) and biotinylated dextran (BD) were injected into the primary auditory neocortex of albino rats (Te1), and labeled corticocollicular fibers were studied via light and electron microscopy. Axons from discrete regions of Te1 form two rostrocaudally oriented laminar plexuses of terminal fibers in the ipsilateral inferior colliculus (IC) and one in the contralateral IC. The first ipsilateral plexus, located in the medial half of the IC, has a dorsomedial to ventrolateral orientation, parallel to the isofrequency planes of the IC; is continuous through the CNIC and DCIC; and extends into the rostral ECIC. The second plexus is located in the deep layers of the lateral ECIC. These two plexuses meet caudally and ventrally, at the border between the CNIC and the lateral ECIC. The plexus in the contralateral IC is less dense and shorter than the two ipsilateral plexuses and is symmetric to the medial plexus. The thickness of the three plexuses is correlated with the size of the injection site, and their mediolateral and dorsoventral positions change as the injection site in Te1 is displaced rostrocaudally, with more caudal injections resulting in more dorsolateral medial plexuses and more dorsomedial lateral plexuses. Furthermore, the ventromedial border of the IC receives nontopographic, convergent projections from wide regions of rostral portions of Te1. The distribution of these corticocollicular plexuses mimics the topography of previously described intracollicular fibers. Electron microscopy shows that, in all three subdivisions of the ipsilateral IC, corticocollicular fibers form small boutons with features generally associated with excitatory transmission; i.e., they contain round synaptic vesicles and form asymmetric synapses with thin dendritic shafts and spines. These results demonstrate that the auditory corticocollicular projections innervate more extensive regions of the IC than were previously observed. Although peripheral regions receive the densest projection, the entire IC appears to be the target of corticofugal input.

Internal pudendal flap anoplasty for severe anal stenosis. Report of a case.

PURPOSE: A technique for introducing anoderm into the anal canal is described. METHODS: An internal pudendal flap was used. RESULTS: This technique was totally successful in alleviating anal stenosis and maintaining fecal continence. CONCLUSION: Internal pudendal flap should be in the armamentarium of the colon and rectal surgeon for treating severe anal stenosis.

Dorsal nucleus of the lateral lemniscus in the rat: concentric organization and tonotopic projection to the inferior colliculus.

A basic principle of organization in auditory centers is the topographic-tonotopic order. Whether this applies to the dorsal nucleus of the lateral lemniscus (DNLL), however, is still debated. To clarify this problem, we have utilized the neuroanatomical tracers horseradish peroxidase (HRP) and biotinylated dextran (BD) injected into different regions of the central nucleus of the inferior colliculus (CNIC) in the rat. After large injections of HRP that included most of the CNIC, retrogradely labelled neurons were found all across the ipsi- and contralateral DNLL, showing that all parts of this nucleus innervate the CNIC bilaterally. More neurons were seen consistently on the side contralateral to the injection site. Labelled fibers, however, were abundant ipsilaterally, but scarce in the contralateral DNLL. Single, small injections of HRP or BD into the CNIC resulted in labelling in restricted areas of the ipsi- and contralateral DNLL. In coronal sections, the neurons and fibers labelled in the ipsilateral DNLL formed a well-defined, ring-shaped structure made of dendrites and axons oriented parallel to each other, which we termed "annular band." The observation of serial sections revealed that the annular band seen in any individual section represents a slice through a more or less complete three-dimensional, hollow, ovoid structure oriented rostrocaudally. The position and diameter of the annular band changed as the injection site was shifted along the tonotopic axis of the CNIC. Single injections placed in the ventromedial, high-frequency region of the CNIC produced a large annular band along the periphery of the DNLL. After injections placed in progressively more dorsolateral, lower-frequency regions of the CNIC, the annular band became smaller in diameter and occupied a successively more central position in the DNLL. Double injections along the tonotopic axis of the CNIC resulted in two roughly concentric annular bands. The labelled neurons and fibers in the contralateral DNLL systematically occupied a position symmetric to the annular band seen ipsilaterally. These findings indicate that the rat DNLL is primarily composed of neurons with flattened dendritic arbors and flattened fields of terminal fibers. These two elements intermingle, forming concentric layers around the geometric center of the nucleus. The axons of neurons within corresponding layers on the two sides converge onto the CNIC of both sides in a strict topographic fashion: the peripheral layers project to the ventromedial, high-frequency region of the CNIC, and the central layers project to the dorsolateral, low-frequency region. These results suggest that the concentric arrangement of the DNLL is the substrate of its tonotopic organization.

Myocutaneous flaps in genitourinary oncology.

Between January 1983 and September 1992, 32 myocutaneous flaps were fashioned in 28 patients for reconstruction following treatment of genitourinary malignancies or complex pelvic fistulas. Of the myocutaneous flaps 14 were used to obtain primary soft tissue coverage of large but otherwise uncomplicated wounds and 10 were used to cover previously irradiated resection sites. Four myocutaneous flaps were used to repair complex radiation-induced fistulas involving the bladder, vagina, urethra and rectum. Flaps were used to cover infected or nonhealing open wounds in 8 cases, 4 of which also had been previously irradiated. Myocutaneous flap donor sites were the tensor fascia lata in 11 cases, gracilis in 9, rectus abdominis in 10 and rectus femoris in 2. There was 1 major complication (flap loss) and 9 minor complications. There were no perioperative deaths. Myocutaneous flaps are an effective means of covering large groin, perineal and lower abdominal surgical defects after radical surgery.

Input from the inferior colliculus to medial olivocochlear neurons in the rat: a double label study with PHA-L and cholera toxin.

The inferior colliculus provides a strong descending influence capable of modulating the excitability levels of olivocochlear neurons (Rajan, 1990). In an attempt to anatomically demonstrate this pathway in rats, an experimental paradigm was designed by which anterogradely transported Phaseolus vulgaris-leucoagglutinin (PHA-L), which delineates axonal arbors, and retrogradely transported cholera toxin B subunit alone (CT-B) or conjugated to horseradish peroxidase (CT-HRP), which delineate dendritic arbors, are visualized in the same brainstem sections. PHA-L was injected unilaterally into the central nucleus of the inferior colliculus of adult rats 5-9 days prior to injection of CT-B or CT-HRP into either the contralateral or the ipsilateral cochlea. Descending collicular axons labeled with PHA-L densely innervate the ventral nucleus of the trapezoid body (VNTB), which contains neurons of the medial olivocochlear system (MOCS), but do not enter the lateral superior olive, where the neurons of the lateral olivocochlear system (LOCS) are found. The collicular projection to VNTB is largely ipsilateral and supplies mostly the ventral half of the nucleus. Within VNTB, the collicular fibers intermingle with dendrites and, to a lesser extent, cell bodies of MOCS. Collicular boutons, predominantly of the en passant type, are often observed in close apposition to dendrites and, less frequently, cell bodies of both crossed and uncrossed MOCS. These light microscopic results suggest the existence of direct, synaptic contacts between descending collicular axons and ipsilateral crossed and uncrossed MOCS. Numerous collicular boutons were also seen at a distance from MOCS, suggesting that they establish synapses with other neuron types of the VNTB that do not send their axons to the cochlea.

Free flap chest wall reconstruction for recurrent breast cancer and radiation ulcers.

Pedicled myocutaneous flaps are the established first choice for soft tissue coverage of major chest wall defects. In some patients, this alternative is not available because the flap itself or its blood supply may be included within the field of surgical resection, the flap may have been used previously, or the defect is too large or extends past the reach of the flap. In these patients, free flaps can be used to provide adequate soft tissue coverage. This report examines 7 women with major full-thickness chest wall defects treated with free flap soft tissue coverage. Either a rectus abdominis (6 women) or a latissimus dorsi myocutaneous free flap (1 woman) was used. There were no flap failures. Permanent protection of prosthetic material used to stabilize the chest wall was provided in all women. Only 1 woman experienced delayed wound healing. Secondary procedures were not required in any patient. Myocutaneous free flaps provide reliable single-stage soft tissue coverage for large chest wall defects that are not suited to reconstruction with pedicled myocutaneous flaps.

Intrinsic and commissural connections of the rat inferior colliculus.

This study analyzes the distribution of the intrinsic and commissural fiber plexuses originating in the central nucleus of the inferior colliculus in the rat. The anterograde tracer Phaseolus vulgaris-leucoagglutinin (PHA-L) was injected iontophoretically at different places along the tonotopic axis of the central nucleus and visualized immunohistochemically. In coronal sections the terminal fields of axons originating at each injection site are seen to create four well-defined bands across the rostrocaudal extent of the inferior colliculus, two in the ipsilateral and two in the contralateral side. The "ipsilateral main band" extends dorsomedially and ventrolaterally from the injection site, in register with the known isofrequency contours of the central nucleus, spanning this nucleus and extending into the dorsal cortex of the inferior colliculus. The "ipsilateral external band" is located in the external cortex, where it is oriented dorsoventrally, slightly oblique to the pial surface. In caudal sections, the ventral portion of these two bands appear to join. The two bands in the contralateral inferior colliculus occupy a symmetric position to those of the ipsilateral side, forming a mirror-like image. The position of the four bands changes as the position of the injection site is varied along the frequency gradient axis of the central nucleus. After ventromedial (high frequency area) injections, the main band is ventral and medial, and the external band ventral and lateral. After more dorsolateral (lower frequency) injections, the main band is more dorsal and lateral, whereas the external band is more dorsal but more medial. Thus, the change in the position of the external band is separate and opposite to that of the main band. We suggest that the main bands represent isofrequency contours. Since the projection from the central nucleus to the external cortex of the inferior colliculus also appears to be tonotopic, we also propose a tonotopic organization for the external cortex. The main bands overlap the terminal field of the lemniscal fibers in the central nucleus; thus, it is concluded that the intracollicular fibers contribute to the formation of the known fibrodendritic laminae of the central nucleus. A possible role in preservation of frequency information and integration of other different acoustic parameters is proposed for the main bands. The external bands could participate in polysensory integration, and the commissural connections could be involved in hitherto unknown stages of binaural processing of sound. Based on our results, several modifications are proposed for delineating the subdivisions of the inferior colliculus.

Projection from the nucleus reuniens thalami to the hippocampal region: light and electron microscopic tracing study in the rat with the anterograde tracer Phaseolus vulgaris-leucoagglutinin.

In order to study the morphological substrate of possible thalamic influence on the cells of origin and area of termination of the projection from the entorhinal cortex to the hippocampal formation, we examined the pathways, terminal distribution, and ultrastructure of the innervation of the hippocampal formation and parahippocampal region by the nucleus reuniens of the thalamus (NRT). We employed anterograde tracing with Phaseolus vulgaris-leucoagglutinin (PHA-L). Injections of PHA-L in the NRT produce fiber and terminal labeling in the stratum lacunosum-moleculare of field CA1 of the hippocampus, the molecular layer of the subiculum, layers I and III/IV of the dorsal subdivision of the lateral entorhinal area (DLEA), and layers I and III-VI of the ventral lateral (VLEA) and medial (MEA) divisions of the entorhinal cortex. Terminal labeling is most dense in the stratum lacunosum-moleculare of field CA1, the molecular layer of the ventral part of the subiculum, MEA, and layer I of the perirhinal cortex. In layer I of the caudal part of DLEA and in MEA, terminal labeling is present in clusters. Injections in the rostral half of the NRT produce the same distribution in the hippocampal region as those in the caudal half of the NRT, although the projections from the rostral half of the NRT are much stronger. A topographical organization is present in the projections from the head of the NRT, so that the dorsal part projects predominantly to dorsal parts of field CA1 and the subiculum and to lateral parts of the entorhinal cortex, whereas the ventral part projects in greatest volume to ventral parts of field CA1 and the subiculum and to medial parts of the entorhinal cortex. The distribution of the reuniens fibers coursing in the cingulate bundle was determined by comparing cases with and without transections of this bundle. The fibers carried by the cingulate bundle exclusively innervate field CA1 of the hippocampus, the dorsal part of the subiculum, and the presubiculum and parasubiculum. They participate in the innervation of the ventral part of the subiculum and MEA. Electron microscopy was used to visualize the axon terminals of PHA-L-labeled reuniens fibers. These terminals possess spherical synaptic vesicles and form asymmetric synaptic contacts with dendritic spines or with thin shafts of spinous dendrites.(ABSTRACT TRUNCATED AT 400 WORDS)

Morphology of cochlear root neurons in the rat.

The morphology of large neurons in the cochlear nerve root of albino rat has been studied with a variety of techniques including Nissl and cell-myelin staining, Golgi impregnation, horseradish peroxidase back-filling of severed axons, transmission electron microscopy, and morphometry. The cells, called root neurons, resemble the globular cells of the ventral cochlear nucleus in having an oval cell body, an eccentric nucleus, an axon that projects centrally via the trapezoid body, and in receiving many primary-like axosomatic boutons. The root neurons, however, are larger than globular cells, and they have at least two types of dendrites oriented, respectively, parallel and across the cochlear nerve fibres. The soma, moreover, has less finely dispersed Nissl material, is less completely covered with terminals, and receives a smaller proportion of presumably inhibitory synapses. So far, this particular type of neuron has been observed only in rat and mouse.

Distribution of primary afferent fibres in the cochlear nuclei. A silver and horseradish peroxidase (HRP) study.

Horseradish peroxidase, when injected intracochlearly, is transported transganglionically to the brain stem cochlear nuclei, thus providing an excellent method for tracing the central projection of the spiral ganglion neurons. Silver impregnation using the Cajal-de Castro method, which stains axons even when inside the bone, was used as a reference technique. The combination of both procedures led to the following conclusions. Primary cochlear afferents are found only in the ventral zone of the dorsal cochlear nucleus. In this area they cover the deep and fusiform cell layers. The molecular layer shows no HRP label. The higher concentration of primary cochlear afferents in the ventral cochlear nucleus appears in its central zone; wide areas in this nucleus are not labelled at all. A thin bundle of primary cochlear afferents runs parallel to, and beneath, the granular region.

[What is wrong with the measles vaccine in Mexico? Study of an epidemic outbrake of measles]. / Qué pasa con la vacuna de sarampión en México? Estudio de un brote epidémico de sarampión

The study included 205 children with measles seen after an epidemic outbreak in Distrito Federal during the first six months of 1976. 65.8% of the cases had not been given specific immunization and out of the 70 vaccinated cases (34.2%), one half of them were under one year old and were not given re-enforcement afterwards. The clinical picture suffered no changes in vaccinated children, 40% of infants showed initial exanthema on chest and abdomen with centrifugal distribution and in 41.5% of them, diarrhea appeared during the prodromal period. The most outstanding elements of this epidemic outbreak were the high number of sensible cases and the high percentage of children vaccinated before the age of one year and who were not later given re-vaccination. Indequate handling of the vaccine or combination of vaccine withe gammaglobulin used in 1969 and 1970, are also mentioned as a possibility to explain failures of the vaccine in ths group of well vaccinated children.