Prenatal or postnatal indomethacin exposure and neonatal gut injury associated with isolated intestinal perforation and necrotizing enterocolitis.

OBJECTIVE: To examine the role of indomethacin in neonatal gut injury. STUDY DESIGN: Infants born at gestational age 23 weeks and with birth weights 400-1200 g were included in this prospective prevalence study of neonatal gut injury. Infants with isolated intestinal perforation (IIP) confirmed at laparotomy or at autopsy or with necrotizing enterocolitis (NEC) were identified. Data were abstracted bi-weekly. RESULT: Among 992 study infants, 58 infants exposed solely to prenatal indomethacin did not show an increased rate of neonatal gut injury. Any postnatal indomethacin exposure (n=611) increased the odds of IIP (OR 4.17, CI, 1.24-14.08, P=0.02) but decreased the odds of NEC (OR 0.65, CI 0.43-0.97, P=0.04). There was a negative association between the timing of indomethacin-exposure and the odds of developing IIP (OR 0.30, CI 0.11-0.83, P=0.02). Compared with NEC, IIP occurred at an earlier age (P<0.05) and was more common (P<0.05) among infants who received early indomethacin (first dose at <12 h of age) to prevent intraventricular hemorrhage than among infants who were treated with late indomethacin for closure of a patent ductus arteriosus (PDA). Unlike the classic hemorrhagic ischemic lesions of NEC in which large areas of tissue were inflamed or necrotic, the IIP lesions were small and discrete. CONCLUSION: Early (<12 h) postnatal indomethacin exposure was associated with an increased odds of IIP in very low birth weight infants whereas its later use for closure of a PDA appeared to provide protection against NEC. The paradoxical effect of the timing of indomethacin on IIP versus on NEC may be related to the different pathogeneses of the two diseases. Our findings also suggest that PDA may contribute to NEC.

Anthropometry as a predictor of high speed performance.

To assess anthropometry as a predictor of high-speed performance, subjects performed four seated knee- and hip-extension workouts with their left leg on an inertial exercise trainer (Impulse Technologies, Newnan GA). Workouts, done exclusively in either the tonic or phasic contractile mode, entailed two one-minute sets separated by a 90-second rest period and yielded three performance variables: peak force, average force and work. Subjects provided the following anthropometric data: height, weight, body mass index, as well as total, upper and lower left leg lengths. Via multiple regression, anthropometry attempted to predict the variance per performance variable. Anthropometry explained a modest (R2=0.27-0.43) yet significant degree of variance from inertial exercise trainer workouts. Anthropometry was a better predictor of peak force variance from phasic workouts, while it accounted for a significant degree of average force and work variance solely from tonic workouts. Future research should identify variables that account for the unexplained variance from high-speed exercise performance.

3-Methylindole alters both olfactory and trigeminal nasal mucosal potentials in rats.

Data from human studies imply that vanillin is an olfactory stimulant, whereas CO2 activates intranasal trigeminal nociceptors. We examined the effects of the olfactotoxin 3-methylindole (3-MI) on nasal mucosal potentials evoked by vanillin and CO2 in rats. A single i.p. administration of 300 mg/kg 3-MI altered both olfactory and trigeminal mucosal responses. Relative to amplitude values determined in non-3-MI-injected rats, the response to vanillin was reduced to 6%, 7%, and 43%, and the response to CO2, recorded in the same rats, decreased to 25%, 38%, and 51% at 4, 8 and 16 days post-3-MI, respectively. The results suggest that 3-MI affects both olfactory and trigeminal elements within the nasal mucosa.

Chronic dexamethasone treatment potentiates insult to olfactory receptor cells produced by 3-methylindole.

The effect of chronic dexamethasone treatment on damage to olfactory receptor cells produced by 3-methylindole (3-MI) was examined. Twelve rats were injected, every other day, with dexamethasone (1.5 mg/kg, i.p.), and 12 rats with saline alone. Injections began 1 week before and continued, in different rats, from 1 to 4 weeks after a single intraperitoneal administration of 150 mg/kg 3-MI. One, two, three, and four weeks after exposure to 3-MI, different groups of rats, three specimens per each treatment condition, received bilateral application of horseradish peroxidase to the olfactory mucosa and were subsequently sacrificed. Anterograde labeling of primary afferents, i.e., an inverse correlate of the degree of cellular damage, was quantitatively determined by measuring the mean optical density (MOD) of staining in sections of the olfactory bulb. In saline-injected rats, the MOD values were 27.0, 46.6, 87.1, and 104.7 for one, two, three, and four post-3-MI weeks, respectively. The corresponding values in the dexamethasone-treated rats were 15.7, 29.7, 87.5, and 110.5. The MOD values of the dexamethasone-injected rats were significantly lower than those of the saline-injected rats for post-3-MI weeks 1 and 2, indicative of stronger damage to olfactory receptor cells in the rats treated with the glucocorticoid. The data suggest that dexamethasone potentiates the 3-MI olfactotoxicity during the first 2 weeks after insult. This effect, at least partly, may be due to the inducing action of dexamethasone on the cytochrome P450 responsible for metabolic bioactivation of 3-MI.

A study testing the routine use of ultrasound measurements when selecting the electron energy for breast boost radiotherapy.

The determination of the depth of the tumour bed within the breast requiring an electron therapy boost dose is generally judged clinically and can be inconsistent between individual radiotherapists. High frequency ultrasound provides a reproducible, safe and quick method of measuring this depth. In order to improve current working practice at the Royal Marsden NHS Trust the routine use of ultrasound when planning breast boost radiotherapy was established. Fifty-three early stage postoperative breast cancer patients had both clinical and ultrasound assessments of boost depth performed. These measurements were converted into electron energy and compared. Measurements ranged from 0.8 cm to 4.9 cm and electron energy from 4 MeV to 15 MeV. As a direct result of the ultrasound measurements taken, 60% of patients had their electron energy changed from that chosen by the clinically assessed measurement. Overall, the energy was as likely to be increased as decreased. Breast size did not influence the need for change but patients with small breasts never required an increase in the energy from that chosen clinically. It was concluded that the use of ultrasound, once integrated into the planning process, can improve accuracy when selecting electron energy for patients receiving breast boost irradiation.

Mechanistic link between lidocaine block and inactivation probed by outer pore mutations in the rat micro1 skeletal muscle sodium channel.

1. Mutations that disrupt Na+ channel fast inactivation attenuate lidocaine (lignocaine)-induced use dependence; however, the pharmacological role of slower inactivation processes remains unclear. In Xenopus oocytes, tryptophan substitution in the outer pore of the rat skeletal muscle channel (micro1-W402) alters partitioning among fast- and slow-inactivated states. We therefore examined the effects of W402 mutations on lidocaine block. 2. Recovery from inactivation exhibited three kinetic components (IF, fast; IM, intermediate; IS, slow). The effects of W402A and W402S on IF and IS differed, but both mutants (with or without beta1 subunit coexpression) decreased the amplitude of IM. In wild-type channels, lidocaine imposed a delayed recovery component with intermediate kinetics, and use-dependent block was attenuated in both W402A and W402S. 3. To examine the pharmacological role of IS relative to IM, drug-exposed beta1-coexpressed channels were subjected to 2 min depolarizations. Lidocaine had no effect on sodium current (INa) after a 1 s hyperpolarization interval that allowed recovery from IM but not IS, suggesting that lidocaine affinity for IS is low. 4. Both W402 mutations reduced occupancy of IM in drug-free conditions, and also induced resistance to use-dependent block. We propose that lidocaine-induced use dependence may involve an allosteric conformational change in the outer pore.

Effects of insulin-like growth factor 1 on olfactory neurogenesis in vivo and in vitro.

The rate of neurogenesis in the peripheral olfactory neuroepithelium is regulated by unknown mechanisms. The members of the insulin-like growth factor (IGF) family can influence neuronal generation, survival and/or differentiation. Several members of this family, in particular IGF-1, are expressed at high levels in the olfactory bulb and epithelium, where they could influence the generation and/or survival of olfactory receptor neurons (ORNs). To explore the role of IGF-1 in the olfactory epithelium (OE), we asked which cells expressed IGF-1 receptors (IGF-1Rs), using olfactory cell cultures and cryostat-cut tissue sections of neonatal (postnatal day four) and adult rat OE. An antibody specific for the alpha subunit of the IGF-1R densely labeled a subset of ORNs but not other cell types in sections and cultures. These ORNs were primarily immature, as determined by double labeling with neuronal markers. The number of IGF-1R-labeled cells as well as the levels of IGF-1R protein (determined by immunoprecipitation and Western blotting) decreased with age, which is consistent with normal developmental changes. To study IGF-1 effects in the intact animal, we infused IGF-1 and related growth factors into the noses of newborn Sprague-Dawley rats, i.e., when the epithelium is still developing. Growth factors or carrier solution (0.9% NaCl with 0.25% bovine serum albumin to prevent nonspecific binding) were applied (10 microliters) to the left nostril once per day starting shortly after birth on postnatal day 1 (P1), P2 and P3, and the animals were sacrificed on P4 by decapitation. After paraformaldehyde immersion fixation, cryostat sections of the olfactory area of the nose were immunostained for the proliferating cell nuclear antigen (PCNA). Sections were position-matched by turbinate structure and then epithelial height and area of PCNA staining at the base of the epithelium (which represents division of primarily neuronal precursors) were measured by image analysis. Both were significantly increased by rat IGF-1 (20 ng/ml, 2.6 nM), but not insulin (20 ng/ml, 2.6 nM) or an IGF-1 derivative, LongR3 IGF-1 (200 ng/ml, 22 nM), that does not bind to the IGF-1 binding proteins (IGFBPs). Thus IGF-1 appears to influence the rate of olfactory neurogenesis, and its actions are not modified by the IGFBPs. These data suggest an important role for IGF-1 in the OE.

A retrospective survey of clusters of meningococcal disease in England and Wales, 1993 to 1995: estimated risks of further cases in household and educational settings.

Information about the epidemiology of meningococcal disease case clusters and the risk of further cases is sparse. Data on clusters in household and educational settings from 1 January 1993 to 31 March 1995 was requested from consultants in communicable disease control in England and Wales through a retrospective postal survey. Ninety-three per cent (122/131) responded. Of the 114 cases in 45 reported clusters, 77 (67.5%) were microbiologically confirmed. The case fatality rate in index cases was higher than in associated cases (18.2% vs 4.5%; p = 0.02). Five out of 11 clusters in household settings consisted only of index and co-primary cases. No further cases occurred within two weeks after giving chemoprophylaxis to household contacts. The relative risks of further cases in the week after the index case arose were estimated to be 1200 for contacts in the household, 160 in secondary schools, 60 in primary schools, 1.8 in universities/colleges, and 0 in nurseries. Between seven and 30 days the relative risks were lower; 150 in households, and between 0 and 13 in all other settings. Beyond 30 days, the relative risk in the household setting was 8 and lower than this in all other settings. The absolute risk of further cases in the month following the index case was calculated as 210 per 100,000 in household members, 7-10/10(5) in pupils at the same school, and 0.6/10(5) in students at the same university or college. The current policy in England and Wales to recommend chemoprophylaxis for household members may prevent half of the further cases in this setting. Raised awareness may have contributed to the lower case fatality rate among household contacts who developed meningococcal disease, but the number of co-primary cases observed should prompt urgent enquiries about current illness in household contacts of index cases. The relative risk of further cases in preschool groups was low and apparently unaffected by changes in chemoprophylactic policy. The relative risk in school settings was raised in the month following a case, but the absolute risk was still low. Further study to quantify the risk in university settings is needed.

Salm-Net facilitates collaborative investigation of an outbreak of Salmonella tosamanga infection in Europe.

Twenty-eight cases of Salmonella tosamanga infection were identified in six western European countries during the first half of 1995. Salm-Net, a European system for collaborative surveillance of gastrointestinal infection, detected the outbreak and coordinated its investigation. There were 28 cases, 14 of each sex, with a broad age distribution. Interviews with cases to identify common food and other exposures failed to generate a working hypothesis. The initial cluster occurred in a period of eight weeks and, since only one further case occurred in June, the investigation was closed. This incident shows that Salm-Net is effective in identifying international outbreaks of human salmonellosis. Practical difficulties in the field investigation of the outbreak are discussed.

Effects of inhalation of cadmium on the rat olfactory system: behavior and morphology.

To investigate the effects of cadmium on olfaction, two separate studies were conducted in which male adult rats were exposed to CdO, via inhalation, for 5 h per day, 5 days a week for 20 weeks. Target exposure values of 250 and 500 micrograms/m3 were measured at 200 and 325 micrograms/m3 for the low concentration in two experiments, and 550 and 660 micrograms/m3 for the high concentration. Prior to exposure, olfactory thresholds were obtained using a conditioned suppression technique. After 20 weeks of cadmium exposure, there was no evidence of anosmia in any of the rats nor were there any significant changes observed in olfactory thresholds. Although olfaction was not impaired, cadmium levels in the olfactory bulbs of exposed rats were significantly elevated compared to controls. Cardiac and respiratory histopathology were observed at all exposure levels, but there was no evidence of nasal pathology related to exposure to cadmium. Failure of cadmium to produce olfactory dysfunction may be due to the protective effects of metallothionein and/or to the highly resilient nature of the rodent olfactory system.

Relationships between the nuclear membrane, nuclear pore complexes, and organelles in the type II pneumocyte.

Functional relationships among organelles of the type II cell are suggested based upon the proximity of organelles to specialized areas of the plasma- and nuclear membranes. In a two-dimensional morphometric analysis of the profiles of organelles in type II cells of the ferret and rat (and beagle dog), lamellar bodies were more likely to be located near the nuclear membrane than at the alveolar space (where exocytosis occurs). The size of lamellar body profiles was not correlated with distance from the nuclear membrane; however, large profiles were nearer the apical membrane, and smaller ones nearer the basement membrane. Profiles of highly branched mitochondria were 10 times more frequently associated with nuclear pore complexes than with the inter-pore nuclear membrane. Forty percent of all mitochondrial profiles were within 0.25 microns of the nucleus, 5% were within 0.02 microns and half of these appeared to touch the filaments of the nuclear pore complexes. The size of mitochondrial profiles was not correlated with distribution. In the ferret and rat, 8.6% and 2.5% respectively, of the nuclear pore complexes were associated with mitochondria. Sebaceous cells, from control mice, demonstrated a spatial distribution of granules which was size dependent but unrelated to the nuclear membrane.

Behavioral, histological, and neurochemical effects of nickel (II) on the rat olfactory system.

Experimentally, inorganic, sulfated nickel compounds (Ni2+) have been shown to produce histological lesions in the nasal mucosa of rats, more specifically, atrophy of the olfactory epithelium. The present project was designed to assess the effects of inhalation of nickel sulfate hexahydrate on behavioral, histological, and neurochemical aspects of the olfactory system. Male Long-Evans rats were exposed to either background air (control) or 635 micrograms Ni/m3 for 16 consecutive days, 6 hr/day. Exposure resulted in selective lesions to the olfactory epithelium. The number of bipolar sensory receptor cells was slightly reduced and there was a significant decrease in the thickness of the olfactory epithelium. This was due primarily to a significant loss of the sustentacular cell population, with a thinning of the apical cytoplasm, concomitant with a reduction in the number of microvilli at the surface of these cells. Significant decreases in carnosine level, consistent with the nickel sulfate exposure, were observed. However, there were no changes in olfactory function as measured by either absolute threshold or two-oder discrimination tasks.

Microvillar cells of the olfactory epithelium: morphology and regeneration following exposure to toxic compounds.

In recent years microvillar cells (MVC) have been identified in the olfactory epithelium of numerous species, including rodents, canines, and primates. However, there is no consensus on the morphologic or histochemical features of this cell, nor is the function of these cells currently known. Previous studies have examined MVC during development and in the mature olfactory epithelium, but not after toxic insult. A microvillar cell, defined by specific morphologic criteria, was studied in adult male Long-Evans rats exposed via inhalation to either 200 ppm methyl bromide for 4 h/day, 4 days/week for 2 weeks, or to 635 micrograms/m3 nickel for 6 h/day for 16 consecutive days, and sacrificed serially over several months. The pattern of recovery for MVC differed according to the severity and specificity of the insult to the olfactory epithelium. With methyl bromide, all cell types were completely depleted from olfactory epithelium immediately after injury, including MVC. MVC were slow to repopulate the epithelium, and appeared only when olfactory epithelium was complete in other respects. With nickel exposure, where the major effect was a gradual decrease in sustentacular cells with a thinning of the apical cytoplasm thickness, MVC showed a decline during exposure, but reappeared during recovery. In both cases, there was no difference in olfactory function, even when MVC were absent from the olfactory epithelium. A mature olfactory epithelium appears to be necessary to support the presence of this MVC, suggesting that it is not crucial to the regeneration processes or recovery of olfactory function, but perhaps plays some role, as yet undefined, in the unperturbed olfactory epithelium.

The effects of chlordane exposure during pre- and postnatal periods at environmentally relevant levels on sex steroid-mediated behaviors and functions in the rat.

Technical chlordane is a mixture of four main isomers (i.e., heptachlor, cis-chlordane, trans-chlordane, and trans-non-achlor) found in meat and dairy products as well as in indoor air of houses treated for termites. These isomers are metabolized to more potent epoxides (heptachlor epoxide and oxychlordane) which accumulate in lipid compartments of tissues and have been shown to reduce chloride influx through GABAA receptor complex channels and to alter steroid levels. However, considering the almost universal human exposure and the potential for accumulation of these agents, very little is known about how chronic, low-level exposures during development affect adult behavior and steroid-mediated processes. Time-pregnant Sprague-Dawley dams (Day 4 of gestation through Day 21 of lactation) and offspring (Day 22 of age through Day 80) were exposed to three levels of technical chlordane (100, 500, or 5000 ng/g) on a daily schedule. The low-exposure level generated heptachlor epoxide and oxychlordane plasma levels in the dam (Day 20) and in the offspring (Day 80) representative of those found in the U.S. populace. Chlordane-dosed offspring exhibited sex- and dose-dependent effects on testosterone levels, behavioral tests, and body weight conducted between postnatal Days 77 and 85. Chlordane-dosed females, but not males, had significant decreases in testosterone levels, significant improvements in spatial abilities (i.e., decreases in Cincinnati maze errors, navigation times, and failures to escape), and significant increases in body weight and in auditory startle-evoked responses. In two other tests, only males were used. These chlordane-dosed males showed significant increases in male-typical mating behaviors and decreases in 36Cl- uptake into brain microsacs. For all behavioral and body weight measurements, dose-response effects were observed for the 100 and 500 ng/g dosed groups. However, the 5000 ng/g dose group responses were closer to those of control values. These results suggest that these cyclodienes masculinize sexually dimorphic functions and behaviors by mimicking sex steroids and/or changing their levels.

Financial resources, parent psychological functioning, parent co-caregiving, and early adolescent competence in rural two-parent African-American families.

We proposed a family process model that links family financial resources to academic competence and socioemotional adjustment during early adolescence. The sample included 90 9-12-year old African-American youths and their married parents who lived in the rural South. The theoretical constructs in the model were measured via a multimethod, multi-informant design. Rural African-American community members participated in the development of the self-report instruments and observational research methods. The results largely supported the hypotheses. Lack of family financial resources led to greater depression and less optimism in mothers and fathers, which in turn were linked with co-caregiving support and conflict. The associations among the co-caregiving processes and youth academic and socioemotional competence were mediated by the development of youth self-regulations. Disruptions in parental co-caregiving interfered with the development of self-regulation. This interference negatively influenced youths' academic competence and socioemotional adjustment.

Olfactory neurons in vitro show phenotypic orientation in epithelial spheres.

Production and differentiation of olfactory neurons occur in spherical, multi-neuronal aggregates that form in cultures where dissociated newborn rat nasal cells are plated on to CNS glial cells. We show here that neuronal cell bodies were primarily located in the peripheral layers of the spheres, and almost every neuronal sphere contained one or several non-cellular central cavities. The dendrite-like processes of the olfactory neurons, immunostained for neuron-specific tubulin or the olfactory marker protein, were aligned and directed towards the central cavities. Olfactory neurons in the intact animal show a similar relationship with the nasal lumen. Non-neuronal cells formed multiple layers centrally, bordering the cavities. This degree of phenotypic re-creation is unusual in a dissociated monolayer culture system.

Adsorption of 222Rn by open-faced and diffusion-barrier canisters at different conditions of temperature and humidity.

Open-faced and diffusion-barrier charcoal canisters were individually exposed to a fixed temperature, humidity, and radon concentration in a chamber for a period of 7 d. The radon progeny activity in the canister under study was measured every 3 h. A total of 15 runs were made for the open-faced canisters and nine runs for the barrier canisters with temperatures and absolute humidities ranging from 15-30 degrees C and 0-15 g m-3, respectively. In addition, several runs were made with the radon, temperature, and humidity changing during the 7 d. Results show that open-faced canisters adsorb radon up to 60% more efficiently at 15 degrees C than at 30 degrees C while the barrier canisters show little temperature dependence. The barrier canisters are much less sensitive to humidity effects than the open-faced canister. When used to measure the radon concentration in air, the open-faced canister integrates over a period of only approximately 48 h while the barrier canister integrates over a period of approximately 96 h. The short integration time and the interference of water adsorption by open-faced canisters indicate that the open-faced canisters should be used for exposure times of 48 h and no longer.

Accumulation of Cd(II) in the CNS depending on the route of administration: intraperitoneal, intratracheal, or intranasal.

The uptake and subsequent neuronal transport of certain heavy metals in the olfactory mucosa may be a major means by which these compounds gain access to the CNS. To contrast olfactory versus blood-borne routes of exposure, three groups (n = 4) of adult Long-Evans rats were exposed to solutions of radiolabeled CdCl2. Exposure was by one of three routes: unilateral intranasal instillation (IN), intratracheal lavage (IT), or intraperitoneal injection (ip). The dose level for the intranasal route was 30 microliters of 1 microM CdCl2 labeled with 1 microCi 109Cd. For IT and ip, the dose was 30 microliters of 1 microM CdCl2 diluted to 300 microliters in saline and labeled with 1 microCi 109Cd. Rats were euthanized 24 hr after exposure, tissue samples were taken, and radioactivity was counted. Cd levels were low in the olfactory bulbs of rats exposed either intratracheally or intraperitoneally. However, in rats intranasally exposed, Cd levels were nearly 40 x higher in olfactory bulbs ipsilateral to the exposed side than in those on the contralateral side. With all routes of exposure, Cd levels in brain samples were only slightly elevated. These results suggest that for certain airborne toxicants, especially those that are excluded from the CNS by the blood-brain barrier, the olfactory system may provide a direct route of entry into the CNS.

Olfactory primary neurons as a route of entry for toxic agents into the CNS.

Reports in the literature suggest that the primary sensory neurons of the olfactory system may provide a direct route of entry for agents into the central nervous system (CNS). To investigate whether cadmium, a heavy metal which is normally excluded from the CNS by the blood-brain barrier, can enter the CNS via the olfactory system, rats were exposed either intranasally (unilaterally) or ip to 109Cd (1 mumol Cd labeled with 1 microCi 109Cd). Rats were allowed to survive 7 days, at which point they were euthanized and the kidneys, livers, right and left forebrains, right and left olfactory bulbs, and right and left olfactory epithelia were removed. Tissues were placed in scintillation vials and radioactivity counted. In rats exposed by intranasal instillation, Cd levels were significantly elevated in the kidney, liver and ipsilateral olfactory bulb and epithelium, but not in the contralateral bulb and epithelium or forebrain areas. With the ip exposure, Cd levels were only elevated in the kidney and liver. In a second study the protocol was repeated (without ip exposure), but the olfactory bulbs and epithelium were washed in EDTA before counting. Cd was still present in the bulbs after washing, suggesting that the metal was internal and not bound to the external membrane. In the final experiment, both time course and dose effect of this phenomenon were explored. Rats were exposed either intransally to 1 mumol Cd labeled with 109Cd (1 microCi) and then sacrificed after 1, 3, 7, or 14 days or were exposed to 0.01, 0.1, or 1.0 mumol Cd labeled with 1 microCi 109Cd and sacrificed after 7 days.(ABSTRACT TRUNCATED AT 250 WORDS)