Decreased serotonergic receptor binding in rhombic lip-derived regions of the medulla oblongata in the sudden infant death syndrome.

The sudden infant death syndrome (SIDS) is postulated to result from a failure of homeostatic responses to life-threatening challenges (e.g. asphyxia, hypercapnia) during sleep. The ventral medulla participates in sleep-related homeostatic responses, including chemoreception, arousal, airway reflex control, thermoregulation, respiratory drive, and blood pressure regulation, in part via serotonin and its receptors. The ventral medulla in humans contains the arcuate nucleus, in which we have shown isolated defects in muscarinic and kainate receptor binding in SIDS victims. We also have demonstrated that the arcuate nucleus is anatomically linked to the nucleus raphé obscurus, a medullary region with serotonergic neurons. We tested the hypothesis that serotonergic receptor binding is decreased in both the arcuate nucleus and nucleus raphé obscurus in SIDS victims. Using quantitative autoradiography, 3H-lysergic acid diethylamide (3H-LSD binding) to serotonergic receptors (5-HT1A-D and 5-HT2 subtypes) was measured blinded in 19 brainstem nuclei. Cases were classified as SIDS (n = 52), acute controls (infants who died suddenly and in whom a complete autopsy established a cause of death) (n = 15), or chronic cases with oxygenation disorders (n = 17). Serotonergic binding was significantly lowered in the SIDS victims compared with controls in the arcuate nucleus (SIDS, 6 +/- 1 fmol/mg tissue; acutes, 19 +/- 1; and chronics, 16 +/- 1; p = 0.0001) and n. raphé obscurus (SIDS, 28 +/- 3 fmol/mg tissue; acutes, 66 +/- 6; and chronics, 59 +/- 1; p = 0.0001). Binding, however, was also significantly lower (p < 0.05) in 4 other regions that are integral parts of the medullary raphé/serotonergic system, and/or are derived, like the arcuate nucleus and nucleus raphé obscurus, from the same embryonic anlage (rhombic lip). These data suggest that a larger neuronal network than the arcuate nucleus alone is involved in the pathogenesis of SIDS, that is, a network composed of inter-related serotonergic nuclei of the ventral medulla that are involved in homeostatic mechanisms, and/or are derived from a common embryonic anlage.

Laryngeal basement membrane thickening is not a reliable postmortem marker for SIDS: results from the Chicago Infant Mortality Study.

It has been suggested that laryngeal basement membrane (LBM) thickening is a pathognomonic postmortem marker for sudden infant death syndrome (SIDS) and is not seen in other causes of explained sudden infant death. To test this hypothesis, we evaluated longitudinal sections of the right hemilarynx taken through the midpoint of the true vocal cord from 129 SIDS cases and 77 postneonatal sudden infant death controls. Using a five-point semi-quantitative scale, maximum LBM thickness (LBMT) for SIDS cases and controls was not statistically different (mean, 2.39 + 0.69 and 2.40 + 0.77, respectively). Likewise, scores based on the average thickness along the entire basement membrane (i.e., "average" score), were not found to be different between SIDS cases and controls. Average and maximum LBMT increased with age in both SIDS cases and controls and were not different between SIDS cases and controls within each age interval. Similar trends in the distribution of maximum and average LBMTs were found between black and Hispanic SIDS and controls; the number of white/non-Hispanic infants was too low for meaningful comparisons. Maximum and average LBMTs were not different in SIDS cases and controls exposed to environmental tobacco compared with unexposed infants. The LBMTs also increased significantly with body weight and length in both SIDS cases and controls. Finally, there were no differences in LBMT in infants intubated prior to death compared with those who were not intubated. From these data, we conclude that LBMT is not pathognomonic of SIDS, is present or absent with equal frequency in SIDS and controls, increases with postnatal age, and does not correlate with passive smoke exposure. Therefore, LBMT should not be used to diagnose SIDS.

Brainstem 3H-nicotine receptor binding in the sudden infant death syndrome.

Maternal cigarette smoking during pregnancy has been shown to be a major risk factor for the sudden infant death syndrome (SIDS). We hypothesized that SIDS is associated with altered 3H-nicotine binding to nicotinic receptors in brainstem nuclei related to cardiorespiratory control and/or arousal. We analyzed 3H-nicotine binding in 14 regions in SIDS and control brainstems using quantitative tissue receptor autoradiography. Three groups were analyzed: SIDS (n = 42), acute controls (n = 15), and a chronic group with oxygenation disorders (n = 18). The arcuate nucleus, postulated to be important in cardiorespiratory control and abnormal in at least some SIDS victims, contained binding below the assay detection limits in all (SIDS and control) cases. We found no significant differences among the 3 groups in mean 3H-nicotine binding in the 14 brainstem sites analyzed. When a subset of the cases were stratified by the history of the presence or absence of maternal cigarette smoking during pregnancy, however, we found that there was no expected increase (upregulation) of nicotinic receptor binding in SIDS cases exposed to cigarette smoke in utero in 3 nuclei related to arousal or cardiorespiratory control. This finding raises the possibility that altered development of nicotinic receptors in brainstem cardiorespiratory and/or arousal circuits put at least some infants, i.e. those exposed to cigarette smoke in utero, at risk for SIDS, and underscores the need for further research into brainstem nicotinic receptors in SIDS in which detailed correlations with smoking history can be made.

Tritiated-naloxone binding to brainstem opioid receptors in the sudden infant death syndrome.

The sudden infant death syndrome (SIDS) is defined as the sudden death of an infant under 1 year of age that remains unexplained after a thorough case investigation, including a complete autopsy. We hypothesized that SIDS is associated with altered 3H - naloxone binding to opioid receptors in brainstem nuclei related to respiratory and autonomic control. We analyzed 3H - naloxone binding in 21 regions in SIDS and control brainstems using quantitative tissue receptor autoradiography. Three groups were analyzed: SIDS (n = 45); acute controls (n = 14); and a chronic group with oxygenation disorders (n = 15). Opioid binding was heavily concentrated in the caudal nucleus of the solitary tract, nucleus parabrachialis medialis, spinal trigeminal nucleus, inferior olive, and interpeduncular nucleus in all cases analyzed (n = 74). The arcuate nucleus on the ventral medullary surface contained negligible binding in all cases (n = 74), and therefore binding was not measurable at this site. We found no significant differences among the three groups in the age-adjusted mean 3H - naloxone binding in 21 brainstem sites analyzed. The only differences we have found to date between SIDS and acute controls are decreases in 3H - quinuclidinyl benzilate binding to muscarinic cholinergic receptors and in 3H - kainate binding to kainate receptors in the arcuate nucleus in alternate sections of this same data set. The present study suggests that there is not a defect in opioid receptor binding in cardiorespiratory nuclei in SIDS brainstems.

CHARGE association: histopathological report of two cases and a review.

BACKGROUND: The CHARGE association (C = coloboma, H = heart disease, A = atresia or stenosis of the choanae, R = retarded growth and development or CNS anomalies, G = genital hypoplasia, and E = ear anomalies or deafness) is a rare, recently well-recognized clinical study. The ophthalmic abnormalities have been described in numerous reports, but the ocular histopathologic findings have not been presented in detail. METHODS: We conducted gross and microscopic studies of eyes of two patients with the CHARGE association obtained postmortem. RESULTS: The eyes in one case had a small, symmetrical, inferior nasal coloboma of the choroid. In the other case, extensive inferior nasal colobomas of the iris, ciliary body, and choroid with retinal dysplasia, ectopic retinal/glial tissue in the sclera and hypoplasia of the optic nerve head were present. CONCLUSION: We document the histopathological features of eyes of two subjects with the CHARGE association. The abnormalities of these eyes were typical ocular colobomas presumably resulting from the failure of complete closure of the optic fissure.

Decreased kainate receptor binding in the arcuate nucleus of the sudden infant death syndrome.

The human arcuate nucleus is postulated to be homologous to ventral medullary surface cells in animals that participate in ventilatory and blood pressure responses to hypercarbia and asphyxia. Recently, we reported a significant decrease in muscarinic cholinergic receptor binding in the arcuate nucleus in victims of the sudden infant death syndrome compared with control patients that died of acute causes. To test the specificity of the deficit to muscarinic cholinergic binding, we examined kainate binding in the arcuate nucleus in the same database. We assessed 3H-kainate binding to kainate receptors with tissue receptor autoradiography in 17 brainstem nuclei. Analysis of covariance was used to examine differences in binding by diagnosis, adjusted for postconceptional age (the covariate). Cases were classified as SIDS, 47; acute control, 15; and chronic group with oxygenation disorder, 17. (Acute controls are infants who died suddenly and unexpectedly and in whom a complete autopsy established a cause of death). The arcuate nucleus was the only region in which there was a significant difference in the age-adjusted mean kainate binding between the SIDS group (37+/-2 fmol/mg tissue) and both the acute controls (77+/-4 fmol/mg tissue) (p < 0.0001) and the chronic group (69+/-4 fmol/mg tissue) (p < 0.0001). There was a positive correlation between the density of muscarinic cholinergic and kainate binding in the SIDS cases only (R = 0.460; p = 0.003). The neurotransmitter deficit in the arcuate nucleus in SIDS victims involves more than one receptor type relevant to carbon dioxide and blood pressure responses at the ventral medullary surface.

[Risk factors for persistent diarrhea]. / Factores de riesgo para la diarrea persistente.

The current concepts in persistent diarrhoea (PD) are reviewed. 102 patients with acute diarrhoea and 85 with PD are studied. All were less than one year old. Information about age, nutritional status, time of breast feeding, previous episodes of acute and persistent diarrhoea and the previous use of drugs is registered. Microbiological and parasitologics studies were done to identify enteric pathogens. To prove the association of PD and the exposure to different risk factors the statistic method of Chi square (chi 2) was used and the odds ratio (OR) estimated. In order of importance and according to the OR the risk factors identified were: previous episodes of PD, malnutrition, less than one month with breast feeding, the use of metronidazol and antibiotics, multiple infections, previous episodes of acute diarrhoea and the identification of enteric pathogens. The most frequent pathogen was Salmonella followed by entero pathogenic Escherichia coli.

Decreased muscarinic receptor binding in the arcuate nucleus in sudden infant death syndrome.

Muscarinic cholinergic activity in the human arcuate nucleus at the ventral medullary surface is postulated to be involved in cardiopulmonary control. A significant decrease in [3H]quinuclidinyl benzilate binding to muscarinic receptors in the arcuate nucleus is now shown to occur in sudden infant death syndrome (SIDS) infants, compared to infants dying acutely of known causes. In infants with chronic oxygenation abnormalities, binding is low in other nuclei, as well as in the arcuate nucleus. The binding deficit in the arcuate nucleus of SIDS infants might contribute to a failure of responses to cardiopulmonary challenges during sleep.

The sudden infant death syndrome: pathologic findings.

The last decade has witnessed a remarkable evolution in fundamental concepts regarding SIDS. It begins to appear now that the phenomenon is more likely the remote consequence of a subtle, physiologic birth defect than a single catastrophic incident. One can only hope that the next 10 years will continue to shed more light on this gradually resolving mystery.

Glomerulosclerosis in the sudden infant death syndrome.

In the past two decades, two groups of investigators have alleged that infants who die of the sudden infant death syndrome (SIDS) have excess numbers of sclerotic glomeruli in their kidneys. This double blind, case-control study was undertaken to test that assertion. Using microscopic sections of the kidney from 153 autopsies (99 SIDS infants and 54 control infants) in the National Institute of Child Health and Human Development (NICHD) Cooperative Epidemiologic Study of Risk Factors for SIDS, we counted relative numbers of sclerotic glomeruli in four fields of renal cortical tissue in two sections from each infant. Our results indicate that there is no difference between the two groups in regard to the proportion of sclerotic glomeruli.

A senior elective program in anatomic pathology.

The faculty of the Department of Pathology at the University of Miami School of Medicine has developed a senior elective program in anatomic pathology for fourth-year students. The program is designed in such a way that the fundamental concepts involved will be easily remembered and clinically useful. The teaching methods, which maximize active learning, include the students' group resolution of challenging unknown autopsy cases, participation in the performance of necropsies, individual presentation of one of their own autopsy cases to the group, and work with several interactive videodisc programs. The program has proved to be both effective and popular. It could be reproduced with relative ease in any academic department of pathology.

Iatrogenic disease in the perinatal period.

The ever-changing complexion of iatrogenic perinatal disease dictates the following: 1. Neonatologists and pediatric pathologists must be aware of the current spectrum of these lesions and ever alert to the appearance of new ones. 2. The neonatologist and pediatric pathologist within any given institution should be in regular, systematic communication with each other concerning lesions of this type. 3. There must be a national network for rapid dissemination or exchange of information among institutions regarding these lesions. The Study Group for the Complications of Perinatal Care (SGCPC), established in 1984 as an international, multicenter, multidisciplinary study group, is committed to the prevention of complications of perinatal care by individual and collective effort. Its individual members include perinatologists, neonatologists, pediatric pathologists, and obstetricians. There are institutional members as well. Activities to date include the development of a standardized perinatal autopsy protocol and the initiation of a uniform system for the categorization of perinatal deaths. If the reader is interested in obtaining further information about the organization, contact Trevor Macpherson, MD, in the Department of Pathology at the Magee-Womens Hospital in Pittsburgh, Pennsylvania.

Pediatric pathology and the autopsy.

The damaging effects of low and declining autopsy rates on the discipline of pediatric pathology are discussed. A survey of autopsy rates in 25 children's hospitals indicates that current rates are about 51%. Strategies for improving autopsy rates are presented.

The Goldston syndrome: report of a case.

We present a case of the Goldston syndrome--that is, cystic renal dysplasia and the Dandy-Walker malformation. The condition was diagnosed by ultrasound in a 635 g fetus in the seventeenth week of gestation. Ultrasound studies showed the fetal head to be somewhat enlarged with slight dilatation of the lateral ventricles and marked dilatation of the fourth ventricle. The kidneys were symmetrically enlarged and multicystic. Autopsy revealed evidence of the oligohydramnios syndrome. The kidneys were typical of the Goldston syndrome as were the microscopic lesions in the liver. To our knowledge this is the first reported case in which this diagnosis was made during intrauterine life.