Overnight observation in former premature infants undergoing inguinal hernia repair

BackgroundOvernight observation for apneic events is standard practice in former preterm infants. However, the literature supporting current protocols is dated. Therefore, we retrospectively evaluated the post-anesthetic risks in these patients.MethodsA retrospective review was conducted on former preterm infants admitted after an inguinal herniorrhaphy between 1/00 and 10/09. The protocol for overnight admission was for patients born before 37 weeks gestation who are less than 60 weeks post-conceptional age (PCA).ResultsThere were 363 patients, of which 23 were <40 weeks PCA (group 1), 244 were 40 to 49.9 weeks PCA (group 2), and 96 were 50 to 60 weeks PCA (group 3). Events registered by alarms occurred in 4 patients (1.1%), 2 from group 1 and 2 from group 2. In Group 1, one occurred during nasogastric tube placement and resolved spontaneously. In group 2, one was apnea-induced bradycardia that resolved spontaneously, and one was in a patient on home monitors with an event similar to home reports. There were no events in group 3.ConclusionConservative guidelines for overnight observation after inguinal hernia repair could be set for patients born before 37 weeks gestation who are under 50 weeks PCA.     

A light and electron microscopic study of the metabotropic glutamate receptor mGluR1a in the normal and kainate-lesioned rat hippocampus

The distribution of the metabotropic glutamate receptor mGluR1a was studied in the normal and kainate-lesioned rat hippocampus using a monoclonal (MAb) and a polyclonal antibody to mGluR1a. Many labeled nonpyramidal neurons were observed in the stratum oriens of CA1 in sections incubated with MAb. In comparison, fewer labeled neurons were observed in this layer in sections incubated with polyclonal antibody. Many nonpyramidal neurons were observed in the stratum lucidum of CA3 and the hilus of the dentate gyrus, with both antibodies. The cell bodies of pyramidal neurons were unlabeled. A dense network of labeled processes was observed in the neuropil of the CA fields at electron microscopy. Some dendrites were very densely labeled and did not contain dendritic spines. These were identified as dendrites of nonpyramidal neurons. Other dendrites contained lightly labeled dendritic shafts, but densely labeled dendritic spines, and were identified as dendrites of pyramidal neurons. Intravenous kainate injections resulted in destruction of pyramidal neurons and a massive decrease in mGluR1a immunoreactivity in the CA fields. This decrease was obvious even at 1–5 d postinjection, when the nonpyramidal neurons in the stratum oriens remained densely labeled, suggesting that pyramidal neurons contributed significantly to mGluR1a staining in the CA fields. We conclude that the dendritic spines of hippocampal pyramidal neurons contain mGluR1a, even though little staining is observed in their parent dendritic shafts or cell bodies.     

Cerebrospinal fluid creatine kinase in acutely psychotic patients

Significantly elevated serum creatine phosphokinase concentrations have been demonstrated in 70% of patients with acute psychosis. Elevations in spinal fluid creatine phosphokinase (CPK) activity have been reported in several neurological diseases, often in association with otherwise normal routine spinal fluid studies. Spinal fluid and serum were obtained simultaneously from 11 patients with acute psychosis, the majority being schizophrenic. Although the serum CPK was elevated in eight of the 11 subjects, spinal fluid glucose, protein, colloidal gold, and CPK were normal in all cases. The theoretical implications of these results are discussed.     

Projections to the visual cortex in the golden hamster.

Retrograde transport of horseradish peroxidase (HRP) was used to determine the origins of afferent connexions to the visual cortex (areas 17, 18a and 18b) in the hamster. The distribution of neurons projecting to the visual cortex from other cortical areas, from the thalamus and from the brainstem was studied using a computer technique for three-dimensional reconstruction. There is a topographically organized projection from the dorsal lateral geniculate nucleus to area 17, but probably to no other of the areas studied. The lateral posterior nucleus of the thalamus (LP) projects to area 18a and weakly to area 17. The lateral nucleus (L) projects to area 18b and also, probably, weakly to area 17. The cortical projections from LP and L are also organized topographically but relatively grossly compared with the geniculo-cortical pathway. There are reciprocal association projections between area 17 and areas 18a and 18b. Areas 18a projects weakly to 18b. The main commissural connexions of the posterior neocortex are between the area 17/18a boundary zones in the two hemispheres, with little between the bodies of area 17. Labelled neurons were found bilaterally in the locus coeruleus, more ipsilaterally than contralaterally, after multiple injections into the visual cortex: single, small injections sometimes resulted in the labelling of a single cell body in the locus coeruleus.     

Postnatal development of dendrites of relay neurons in the lateral geniculate nucleus of the marmoset (Callithrix jacchus): a quantitative Golgi study

Dendrites of multipolar relay neurons in the lateral geniculate nucleus of the marmoset (Callithrix jacchus), at various ages from birth to adulthood, were studied in rapid Golgi preparations. The dendrites were analyzed by means of three-dimensional computer reconstructions and decomposed into intermediate and terminal segments, both of which were further classified according to their centrifugal order. Measurements were made of the number of segments per dendrite, the total length of dendrites, and the mean length of intermediate and terminal segments. In adult marmosets, there are four stem dendrites on average per neuron, and each dendrite divides into a mean of 14 segments. Between birth and 6 weeks of age, the mean dendritic length doubles, mainly because of changes in terminal segments. There is a significant decrease in dendritic length into adulthood. The total number of stem dendrites does not change after birth, but during the first postnatal week dendrites lose distal segments, after which there is a significant increase in the number of segments of orders 3 to 7. The mean length of intermediate segments does not change with age, nor with order, whereas the length of terminal segments increases from 50 to 120 microns from birth to 6 weeks of age, and then decreases to the adult value of 80 microns. In conclusion, during the period of most rapid visual development, important morphological changes occur in geniculate relay-cell dendrites, involving essentially terminal segments. These observations correlate well with changes of geniculate volume and neuronal density.