Importance of Ileum and Colon in Children with Short Bowel Syndrome

BACKGROUND

It is well known that small bowel length is a dominant prognostic indicator in patients with short bowel syndrome (SBS). The relative importance of jejunum, ileum, and colon is less well defined in children with SBS. Here we review the outcome of children with SBS with respect to the type of remnant intestine.

METHODS

A retrospective review of 51 children with SBS was conducted at a single institution. The duration of parenteral nutrition use was the main outcome variable. The length of the remaining intestine as well as the type of intestine were recorded for each patient. Kaplan-Meier analyses were conducted to compare the subgroups.

RESULTS

Children with greater than 10% expected small bowel length or more than 30 cm of small bowel achieved enteral autonomy faster than those with less. The presence of ileocecal valve enhanced the ability to wean from parenteral nutrition. The presence of ileum significantly enhanced the ability to wean from parenteral nutrition. Patients with the entire colon also achieved enteral autonomy sooner than those with partial colon.

CONCLUSIONS

The preservation of ileum and colon is important in patients with SBS. Approaches to preserve or lengthen ileum and colon may be beneficial for these patients.

LEVEL OF EVIDENCE

IV.

Delayed appearance of mature ganglia in an infant with an atypical presentation of total colonic and small bowel aganglionosis: a case report

Background

Total colonic and small bowel aganglionosis (TCSA) occurs in less than 1% of all Hirschsprung’s disease patients. Currently, the mainstay of treatment is surgery. However, in patients with TCSA, functional outcomes are often poor. A characteristic transition zone in TCSA can be difficult to identify which may complicate surgery and may often require multiple operations.

Case presentation

We present the case of a male infant who was diagnosed with biopsy-proven total colonic aganglionosis with extensive small bowel involvement as a neonate. The patient was diverted at one month of age based on leveling biopsies at 10 cm from the Ligament of Treitz. At 7 months of age, during stoma revision for a prolapsed stoma, intra-operative peristalsis was observed in nearly the entire length of the previously aganglionic bowel, and subsequent biopsies demonstrated the appearance of mature ganglion cells in a previously aganglionic segment.

Conclusions

TCSA remains a major challenge for pediatric surgeons. Our case introduces new controversy to our understanding of aganglionosis. Our observations warrant further research into the possibility of post-natal ganglion maturation and encourage surgeons to consider a more conservative surgical approach.

Nutritional Needs and Support for Children with Chronic Liver Disease

Malnutrition has become a dangerously common problem in children with chronic liver disease, negatively impacting neurocognitive development and growth. Furthermore, many children with chronic liver disease will eventually require liver transplantation. Thus, this association between malnourishment and chronic liver disease in children becomes increasingly alarming as malnutrition is a predictor of poorer outcomes in liver transplantation and is often associated with increased morbidity and mortality. Malnutrition requires aggressive and appropriate management to correct nutritional deficiencies. A comprehensive review of the literature has found that infants with chronic liver disease (CLD) are particularly susceptible to malnutrition given their low reserves. Children with CLD would benefit from early intervention by a multi-disciplinary team, to try to achieve nutritional rehabilitation as well as to optimize outcomes for liver transplant. This review explains the multifactorial nature of malnutrition in children with chronic liver disease, defines the nutritional needs of these children, and discusses ways to optimize their nutritional.

Management of short bowel syndrome in postoperative very low birth weight infants

Short bowel syndrome is a potentially devastating morbidity for the very low birth weight infant and family with a high risk for mortality. Prevention of injury to the intestine is the ideal, but, if and when the problem arises, it is important to have a systematic approach to manage nutrition, use pharmaceutical strategies and tools to maximize the outcome potential. Safely maximizing parenteral nutrition support by providing adequate macronutrients and micronutrients while minimizing its hepatotoxic effects is the initial postoperative strategy. As the infant stabilizes and starts to recover from that initial injury and/or surgery, a slow and closely monitored enteral nutrition approach should be initiated. Enteral feeds can be complemented with medications and supplements emerging as valuable clinical tools. Engaging a multidisciplinary team of neonatologists, gastroenterologists, pharmacists, skilled clinical nutrition support staff including registered dietitians and nutrition support nurses will facilitate optimizing each and every infant's long term result. Promoting intestinal rehabilitation and adaptation through evidence-based practice where it is found, and ongoing pursuit of research in this rare and devastating disease, is paramount in achieving optimal outcomes.

Parenteral Nutrition-Associated Cholestasis Related to Parental Care

Parenteral nutrition-associated cholestasis (PNAC) is a complication not uncommon in the pediatric population. In severe cases, patients require a liver transplant. To our knowledge, we report the only case of PNAC with end-stage liver failure in a child with short bowel syndrome that resolved with a change in caretaker. Until his care was transferred from his abusive parents, he was frequently admitted for infection and sepsis. His liver function vastly improved from aspartate aminotransferase (AST) 3139 units/L, conjugated bilirubin 25.9 mg/dL to AST 47 units/L, direct bilirubin 0.3 mg/dL under the care of his attentive foster mother, and a liver transplant was no longer necessary. Bacterial infection and sepsis are risk factors correlated with patients with PNAC requiring liver transplant. Prevention of infection by a good caregiver may be a means to reduce the incidence of PNAC.

Echinocandin and ethanol lock therapy treatment of fungal catheter infections

Ethanol lock therapy has been implemented to prevent infections of central venous catheters as well as to treat infections. Fungal catheter-associated blood stream infections are historically more difficult to treat and have required removal of central venous catheters. We report the largest case series to date, successfully treating 5 of 7 fungal catheter-associated blood stream infections with ethanol lock therapy and systemic echinocandin administration.

Aluminum exposure in neonatal patients using the least contaminated parenteral nutrition solution products

Aluminum (Al) is a contaminant in all parenteral nutrition (PN) solution component products. Manufacturers currently label these products with the maximum Al content at the time of expiry. We recently published data to establish the actual measured concentration of Al in PN solution products prior to being compounded in the clinical setting [1]. The investigation assessed quantitative Al content of all available products used in the formulation of PN solutions. The objective of this study was to assess the Al exposure in neonatal patients using the least contaminated PN solutions and determine if it is possible to meet the FDA “safe limit” of less than 5 μg/kg/day of Al. The measured concentrations from our previous study were analyzed and the least contaminated products were identified. These concentrations were entered into our PN software and the least possible Al exposure was determined. A significant decrease (41%–44%) in the Al exposure in neonatal patients can be achieved using the least contaminated products, but the FDA “safe limit” of less than 5 μg/kg/day of Al was not met. However, minimizing the Al exposure may decrease the likelihood of developing Al toxicity from PN.

Aluminum in pediatric parenteral nutrition products: measured versus labeled content

OBJECTIVE

Aluminum is a contaminant in all parenteral nutrition solutions. Manufacturers currently label these products with the maximum aluminum content at the time of expiry, but there are no published data to establish the actual measured concentration of aluminum in parenteral nutrition solution products prior to being compounded in the clinical setting. This investigation assessed quantitative aluminum content of products commonly used in the formulation of parenteral nutrition solutions. The objective of this study is to determine the best products to be used when compounding parenteral nutrition solutions (i.e., those with the least amount of aluminum contamination).

METHODS

All products available in the United States from all manufacturers used in the production of parenteral nutrition solutions were identified and collected. Three lots were collected for each identified product. Samples were quantitatively analyzed by Mayo Laboratories. These measured concentrations were then compared to the manufacturers' labeled concentration.

RESULTS

Large lot-to-lot and manufacturer-to-manufacturer differences were noted for all products. Measured aluminum concentrations were less than manufacturer-labeled values for all products.

CONCLUSIONS

The actual aluminum concentrations of all the parenteral nutrition solutions were significantly less than the aluminum content based on manufacturers' labels. These findings indicate that 1) the manufacturers should label their products with actual aluminum content at the time of product release rather than at the time of expiry, 2) that there are manufacturers whose products provide significantly less aluminum contamination than others, and 3) pharmacists can select products with the lowest amounts of aluminum contamination and reduce the aluminum exposure in their patients.

Refeeding syndrome

Refeeding syndrome (RFS) is the result of aggressive enteral or parenteral feeding in a malnourished patient, with hypophosphatemia being the hallmark of this phenomenon. Other metabolic abnormalities, such as hypokalemia and hypomagnesemia, may also occur, along with sodium and fluid retention. The metabolic changes that occur in RFS can be severe enough to cause cardiorespiratory failure and death. This article reviews the pathophysiology, the clinical manifestations, and the management of RFS. The key to prevention is identifying patients at risk and being aware of the potential complications involved in rapidly reintroducing feeds to a malnourished patient.

Nordihydroguaiaretic acid (NDGA), an inhibitor of the HER2 and IGF-1 receptor tyrosine kinases, blocks the growth of HER2-overexpressing human breast cancer cells

We have reported that nordihydroguaiaretic acid (NDGA) inhibits the tyrosine kinase activities of the IGF-1 receptor (IGF-1R) and the HER2 receptor in breast cancer cells. Herein, we studied the effects of NDGA on the growth of estrogen receptor (ER) positive MCF-7 cells engineered to overexpress HER2 (MCF-7/HER2-18). These cells are an in vitro model of HER2-driven, ER positive, tamoxifen resistant breast cancer. NDGA was equally effective at inhibiting the growth of both parental MCF-7 and MCF-7/HER2-18 cells. Half maximal effects for both cell lines were in the 10-15 microM range. The growth inhibitory effects of NDGA were associated with an S phase arrest in the cell cycle and the induction of apoptosis. NDGA inhibited both IGF-1R and HER2 kinase activities in these breast cancer cells. In contrast, Gefitinib, an epidermal growth factor receptor inhibitor but not an IGF-1R inhibitor, was more effective in MCF-7/HER2-18 cells than in the parental MCF-7 cells and IGF binding protein-3 (IGFBP-3) was more effective against MCF-7 cells compared to MCF-7/HER2-18. MCF-7/HER2-18 cells are known to be resistant to the effects of the estrogen receptor inhibitor, tamoxifen. Interestingly, NDGA not only inhibited the growth of MCF-7/HER2-18 on its own, but it also demonstrated additive growth inhibitory effects when combined with tamoxifen. These studies suggest that NDGA may have therapeutic benefits in HER2-positive, tamoxifen resistant, breast cancers in humans.

Alteplase for the treatment of central venous catheter occlusion in children: results of a prospective, open-label, single-arm study (The Cathflo Activase Pediatric Study)

PURPOSE

Alteplase is approved for use in the restoration of function to occluded central venous access devices (CVADs); however, there are few prospective studies in children. This study was undertaken to evaluate the safety and efficacy of alteplase in the treatment of CVAD occlusions in a pediatric population.

MATERIALS AND METHODS

A prospective, multicenter, open-label, single-arm study evaluating a maximum of two doses (< or =2 mg per dose) of alteplase was performed in pediatric patients. Inclusion criteria included patient age less than 17 years with an occluded CVAD (single-, double-, and triple-lumen catheter or implanted port). Patients with hemodialysis catheters, those with known mechanical occlusion, or those considered at high risk for bleeding or embolization were excluded. Assessment of function was made 30 and 120 minutes (if required) after each dose. The primary objective of the study was to evaluate the safety of alteplase as measured by the incidence of intracranial hemorrhage (ICH); secondary objectives included the evaluation of specific targeted serious adverse events and efficacy of alteplase in the restoration of catheter function.

RESULTS

A total of 310 patients (174 male patients, 136 female patients; mean age, 7.2 years; range, 0.04-18.3 y) were treated; 55 of the patients (17.7%) were younger than 2 years of age. No patients experienced ICH (95% CI, 0%-1.2%). Nine serious adverse events were noted in eight patients (2.6% incidence), two of which were attributed by the investigator to study drug administration (one case of sepsis and one case of a ruptured catheter lumen). The cumulative rate of restoration of CVAD function after serial administration of a maximum of two instillations of alteplase, each with a maximum dwell time of 120 minutes, was 82.9% (95% CI, 78.2%-86.9%). Similar rates of catheter function restoration were seen among all catheter types studied; there were no clinically meaningful differences among age or sex subgroups.

CONCLUSION

The administration of alteplase is safe and effective for the restoration of function to CVADs in pediatric patients.

The use of IV fat in neonates

IV fat emulsion (IVFE) is an integral part of the parenteral nutrition (PN) regimen in neonates. It provides a concentrated isotonic source of calories and prevents or reverses essential fatty acid deficiency. Continuous administration of IV fat with PN regimens prolongs the viability of peripheral IV lines in infants who might have limited venous access. IVFE must be administered separately from the PN solution in neonates. The acidic pH of a PN solution is necessary for maximum solubility of calcium and phosphorus. If fat emulsion is added to the PN solution, as is done in 3-in-1 (total nutrient admixture) solutions, the high amount of calcium and phosphorus needed by these infants may result in an unseen precipitate with serious consequences. Continuous fat infusion over 24 hours is the preferred method in neonates. The administration rate of 0.15 g/kg/hour for IVFE in the neonate should not be exceeded. Essential fatty acid deficiency can be prevented in neonates by providing IVFE in a dose of 0.5-1.0 g/kg/day. Carnitine is not routinely required to metabolize IVFE in the neonate. Infants should receive 20% lipid emulsion to improve clearance of triglycerides and cholesterol. Serum triglyceride levels should be maintained at <150-200 mg/dL in neonates. There are concerns about potential adverse effects of early administration of IV fat in very-low-birth-weight infants weighing <800 g. We hold the IV fat dose at 1.0-1.5 g/kg/day until the second week of life in infants <30 weeks gestation.

Treatment of catheter occlusion in pediatric patients

A proper initial assessment of catheter occlusion is the key to successful management. The assessment screens are for both thrombotic and nonthrombotic causes (including mechanical occlusion). If mechanical occlusion is excluded, thrombotic occlusion is treated with alteplase. Nonthrombotic occlusions are treated according to their primary etiologies: lipid occlusion is treated with 70% ethanol, mineral precipitates are treated with 0.1-N hydrochloric acid (HCl), drug precipitates are treated according to their pH-acidic drugs can be cleared with 0.1-N HCl, basic medications can be cleared with sodium bicarbonate or 0.1-N sodium hydroxide (NaOH). Prevention of occlusion of central venous access devices is also critical. To date, no data conclusively show heparin flushes to be superior to saline flushes. No prophylactic regimen, including low-dose warfarin, low-molecular-weight heparin, or 1 unit heparin/mL of parenteral nutrition has been endorsed by any major medical, nursing, or pharmacy group due to lack of scientific evidence. The most encouraging information on decreasing occlusion rate comes from experience with positive-pressure devices that attach to the hub of most catheter lumens and prevent retrograde blood flow and, consequently, decrease the risk of thrombus formation in the catheter lumen.

Diarylureas are small-molecule inhibitors of insulin-like growth factor I receptor signaling and breast cancer cell growth

In breast and certain other cancers, receptor tyrosine kinases, including the insulin-like growth factor I receptor (IGF-IR), play an important role in promoting the oncogenic process. The IGF-IR is therefore an important target for developing new anti-breast cancer therapies. An initial screening of a chemical library against the IGF-IR in breast cancer cells identified a diaryl urea compound as a potent inhibitor of IGF-IR signaling. This class of compounds has not been studied as inhibitors of the IGF-IR. We studied the effectiveness of one diaryl urea compound, PQ401, at antagonizing IGF-IR signaling and inhibiting breast cancer cell growth in culture and in vivo. PQ401 inhibited autophosphorylation of the IGF-IR in cultured human MCF-7 cells with an IC50 of 12 micromol/L and autophosphorylation of the isolated kinase domain of the IGF-IR with an IC50 <1 micromol/L. In addition, PQ401 inhibited the growth of cultured breast cancer cells in serum at 10 micromol/L. PQ401 was even more effective at inhibiting IGF-I-stimulated growth of MCF-7 cells (IC50, 6 micromol/L). Treatment of MCF-7 cells with PQ401 was associated with a decrease in IGF-I-mediated signaling through the Akt antiapoptotic pathway. Twenty-four hours of treatment with 15 micromol/L PQ401 induced caspase-mediated apoptosis. In vivo, treatment with PQ401 (i.p. injection thrice a week) reduced the growth rate of MCNeuA cells implanted into mice. These studies indicate that diaryl urea compounds are potential new agents to test in the treatment of breast and other IGF-I-sensitive cancers.

Gastrointestinal manifestations of food allergies in pediatric patients

Foods that account for 90% of allergic reactions in children are cow's milk protein, eggs, peanut, soy, tree nuts, fish, and wheat. Food allergy can manifest as urticaria/angioedema, anaphylaxis, atopic dermatitis, respiratory symptoms, or a gastrointestinal (GI) disorder. GI allergic manifestations can be classified as immunoglobulin E (IgE) mediated (immediate GI hypersensitivity and oral allergy syndrome); "mixed" GI allergy syndromes (involving some IgE components and some non-IgE or T-cell-mediated components) include eosinophilic esophagitis and eosinophilic gastroenteritis. Non-IgE-mediated or T-cell-mediated allergic GI disorders include dietary protein enteropathy, protein-induced enterocolitis, and proctitis. All these conditions share a common denominator: the response of the immune system to a specific protein leading to pathologic inflammatory changes in the GI tract. This immunological response can elicit symptoms such as diarrhea, vomiting, dysphagia, constipation, or GI blood loss, symptoms consistent with a GI disorder. The detection of food allergies can be accomplished by the use of radioallergosorbent (RAST) testing and skin prick tests in helping to assess the IgE-mediated disorders. Patch tests may help evaluate delayed hypersensitivity reactions. Treatment of GI allergic disorders ranges from strict dietary elimination of offending food(s), use of protein hydrolysates, and use of L-amino acid-based formula when protein hydrolysates fail. Treatment with topical (for eosinophilic esophagitis) or systemic steroids is used if all dietary measures are unsuccessful. Maternal breast feeding or the use from birth of hydrolysate formulas (extensive or partial hydrolysates) may be efficacious in the prevention of atopic disease in "high-risk" families (with at least 1 parent or sibling with a history of atopic disease).

The use of alteplase for restoring patency to occluded central venous access devices in infants and children

A 21-month retrospective review was completed at the Lucile Packard Children's Hospital to assess the experience of 22 infants and children who received alteplase for the clearance of occluded central venous access devices. After the first dose, 86% (n = 19) of the catheters cleared. Two additional catheters cleared with a second dose. With alteplase treatment, 95% (n = 21) of the catheters cleared. No adverse events were noted within 24 hours after the alteplase was received. Infusion of alteplase appeared to be safe and effective in restoring patency to occluded central venous access devices in infants and children.

Copper Deficiency During Parenteral Nutrition: A Report of Four Pediatric Cases

The standard of care for patients with cholestasis (direct bilirubin >or=2 mg/dL) while receiving parenteral nutrition (PN) solutions is to reduce or discontinue the copper and manganese. The repercussions of this action have not been studied. Two adult case reports document low serum copper levels associated with clinical symptoms of copper deficiency after the removal of copper from their PN solutions. We now describe the first known series of pediatric patients to develop copper deficiency after copper was removed from their PN solutions.

Cellular distribution of NMDA glutamate receptor subunit mRNAs in the human cerebellum

We have used a quantitative in situ hybridization method with human ribonucleotide probes to examine the regional and cellular distribution of N-methyl-D-aspartate receptor (NMDAR) subunit mRNAs in the human cerebellum. Purkinje cells showed very dense labeling for NMDAR1 mRNA, dense labeling for NMDAR2A mRNA, and moderate labeling for NMDAR2D mRNA, whereas labeling for NMDAR2C mRNA was low. Granule cells showed high hybridization signals for the NMDAR1 and NMDAR2C mRNAs and moderate signals for the NMDAR2A and NMDAR2D mRNAs. In addition intense labeling with the NMDAR2B probe was observed in medium-sized neurons with chromophilic cell bodies in the upper part of the granule cell layer, most likely representing Golgi cells. Neurons in the molecular layer, i.e., basket cells and stellate cells, showed moderate hybridization signals for NMDAR1 and NMDAR2D and low signal for NMDAR2C. Each type of cerebellar neuron analyzed displayed a distinct NMDAR2 subunit profile, suggesting that they are likely to have NMDA receptors with distinct properties.

Altered neurotransmitter receptor expression in transgenic mouse models of Huntington's disease

Alterations in neurotransmitter receptors are a pathological hallmark of the neurodegeneration seen in Huntington's disease (HD). However, the significance of these alterations has been uncertain, possibly reflecting simply the loss of brain cells. It is not known for certain whether the alteration of neurotransmitter receptors occurs before the onset of symptoms in human HD. Recently we developed transgenic mice that contain a portion of a human HD gene and develop a progressive abnormal neurological phenotype. Neurotransmitter receptors that are altered in HD (receptors for glutamate, dopamine, acetylcholine and adenosine) are decreased in the brain transgenic mice, in some cases before the onset of behavioural or motor symptoms. In transgenic mice, neurotransmitter receptor alterations occur before neuronal death. Further, receptor alterations are selective in that certain receptors, namely N-methyl-D-aspartate and gamma-aminobutyric acid receptors, are unaltered. Finally, receptor decreases are preceded by selective decreases in the corresponding mRNA species, suggesting the altered transcription of specific genes. These results suggest that (i) receptor decreases precede, and therefore might contribute to, the development of clinical symptoms, and (ii) altered transcription of specific genes might be a key pathological mechanism in HD.

The human N-methyl-D-aspartate receptor 2C subunit: genomic analysis, distribution in human brain, and functional expression

cDNAs encoding four isoforms of the human NMDA receptor (NMDAR) NMDAR2C (hNR2C-1, -2, -3, and -4) have been isolated and characterized. The overall identity of the deduced amino acid sequences of human and rat NR2C-1 is 89.0%. The sequences of the rat and human carboxyl termini (Gly925-Val1,236) are encoded by different exons and are only 71.5% homologous. In situ hybridization in human brain revealed the expression of the NR2C mRNA in the pontine reticular formation and lack of expression in substantia nigra pars compacta in contrast to the distribution pattern observed previously in rodent brain. The pharmacological properties of hNR1A/2C were determined by measuring agonist-induced inward currents in Xenopus oocytes and compared with those of other human NMDAR subtypes. Glycine, glutamate, and NMDA each discriminated between hNR1A/2C-1 and at least one of hNR1A/2A, hNR1A/2B, or hNR1A/2D subtypes. Among the antagonists tested, CGS 19755 did not significantly discriminate between any of the four subtypes, whereas 5,7-dichlorokynurenic acid distinguished between hNR1A/2C and hNR1A/2D. Immunoblot analysis of membranes isolated from HEK293 cells transiently transfected with cDNAs encoding hNR1A and each of the four NR2C isoforms indicated the formation of heteromeric complexes between hNR1A and all four hNR2C isoforms. HEK293 cells expressing hNR1A/ 2C-3 or hNR1A/2C-4 did not display agonist responses. In contrast, we observed an agonist-induced elevation of intracellular free calcium and whole-cell currents in cells expressing hNR1A/2C-1 or hNR1A/2C-2. There were no detectable differences in the macroscopic biophysical properties of hNR1A/2C-1 or hNR1A/2C-2.

Simultaneous isotopic and nonisotopic in situ hybridization histochemistry with cRNA probes

In situ hybridization histochemistry is widely used to study gene expression at the mRNA level in tissues and cells. Double label in situ hybridization allows for coexpression studies. We describe a protocol for the simultaneous hybridization of two cRNA probes tagged with and digoxigenin-UTP, respectively, to frozen brain tissue sections. Hybridization signals of digoxigenin-tagged probes appear as purple cytoplasmic staining following detection of digoxigenin residues by an alkaline-phosphatase-(AP)-linked antibody. Signals resulting from hybridization of radiolabeled probes are detected as silver grains overlying cellular profiles in sections coated with autoradiographic emulsion. Grain counting allows for semiquantitatively estimates of the cellular expression levels of transcripts. Suitable cRNA-probes can be derived from linear templates generated by polymerase chain reaction (PCR) using nested primers which contain RNA-polymerase promotor sites. The cRNA-probes are sensitive and allow an application of this protocol to the detection of a wide range of mRNAs of medium or low abundance.

Altered brain neurotransmitter receptors in transgenic mice expressing a portion of an abnormal human huntington disease gene

Loss of neurotransmitter receptors, especially glutamate and dopamine receptors, is one of the pathologic hallmarks of brains of patients with Huntington disease (HD). Transgenic mice that express exon 1 of an abnormal human HD gene (line R6/2) develop neurologic symptoms at 9-11 weeks of age through an unknown mechanism. Analysis of glutamate receptors (GluRs) in symptomatic 12-week-old R6/2 mice revealed decreases compared with age-matched littermate controls in the type 1 metabotropic GluR (mGluR1), mGluR2, mGluR3, but not the mGluR5 subtype of G protein-linked mGluR, as determined by [3H]glutamate receptor binding, protein immunoblotting, and in situ hybridization. Ionotropic alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid and kainate receptors were also decreased, while N-methyl-D-aspartic acid receptors were not different compared with controls. Other neurotransmitter receptors known to be affected in HD were also decreased in R6/2 mice, including dopamine and muscarinic cholinergic, but not gamma-aminobutyric acid receptors. D1-like and D2-like dopamine receptor binding was drastically reduced to one-third of control in the brains of 8- and 12-week-old R6/2 mice. In situ hybridization indicated that mGluR and D1 dopamine receptor mRNA were altered as early as 4 weeks of age, long prior to the onset of clinical symptoms. Thus, altered expression of neurotransmitter receptors precedes clinical symptoms in R6/2 mice and may contribute to subsequent pathology.

Expression of N-methyl-D-aspartate receptor subunit mRNAs in the human brain: hippocampus and cortex

N-methyl-D-aspartate receptor (NR) activation in the hippocampus and neocortex plays a central role in memory and cognitive function. We analyzed the cellular expression of the five NR subunit (NR1 and NR2A-D) mRNAs in these regions with in situ hybridization and human ribonucleotide probes. Film autoradiograms demonstrated a distinct pattern of hybridization signal in the hippocampal complex and the neocortex with probes for NR1, NR2A, and NR2B mRNA. NR2C and NR2D probes yielded scattered signals without a distinct organization. At the emulsion level, the NR1 probe produced high-density hybridization signals across the hippocampal complex. NR2A mRNA was higher in dentate granule cells and pyramidal cells in CA1 and subiculum compared to hilus neurons. NR2B mRNA expression was moderate throughout, with higher expression in dentate granule cells, CA1 and CA3 pyramidal cells than in hilus neurons. In the hippocampal complex, the NR2C probe signal was not different from background in any region, whereas the NR2D probe signal resulted in low to moderate grain densities. We analyzed NR subunit mRNA expression in the prefrontal, parietal, primary visual, and motor cortices. All areas displayed strong NR1 hybridization signals. NR2A and NR2B mRNAs were expressed in cortical areas and layers. NR2C mRNA was expressed at low levels in distinct layers that differed by region and the NR2D signal was equally moderate throughout all regions. Pyramidal cells in both hippocampus and neocortex express NR1, NR2A, NR2B, and, to a lesser extent, NR2D mRNA. Interneurons or granular layer neurons and some glial cells express NR2C mRNA.

Expression of N-methyl-D-aspartate receptor subunit mRNAs in the human brain: striatum and globus pallidus

N-methyl-D-aspartate receptors (NRs) play an important role in basal ganglia function. By using in situ hybridization with ribonucleotide probes, we investigated the regional and cellular distribution of NR subunit mRNA expression in the human basal ganglia: caudate nucleus, putamen, lateral globus pallidus (LGP), and medial globus pallidus (MGP). Analysis of both film autoradiograms and emulsion-dipped slides revealed distinct distribution patterns for each subunit. On film autoradiograms, the signal for NR1, NR2B, and NR2C in the striatum (STR) was higher than in globus pallidus (GP). The NR2D probe gave a stronger signal in GP than in STR. For NR2A we found a signal in all regions. Analysis of emulsion-dipped sections demonstrated that in striatal neurons, the NR2B signal was higher than in GP neurons. In GP neurons, NR2D was more abundant than in striatal neurons. Despite the relatively low signal on film for NR2C in GP, we found a slightly higher signal in GP per neuron than in STR since in the pallidal areas neurons were sparse but intensely labeled. NR1 and NR2A were more evenly distributed over neurons of STR and GP Between the different parts of STR and GP, we observed only minor differences in the expression of NRs. In MGP a subpopulation of neurons exhibiting low NR2D signals could be separated from the majority of neurons showing an intense NR2D signal. Since the physiological properties of NRs are dependent on subunit composition, these data suggest a high degree of regional specialization of NR properties in the human basal ganglia.

Expression of group one metabotropic glutamate receptor subunit mRNAs in neurochemically identified neurons in the rat neostriatum, neocortex, and hippocampus

Metabotropic glutamate receptors (mGluRs) can be divided into three groups based on sequence homology and pharmacology. We studied expression of group I mGluRs (mGluR1 and mGluR5) in identified neurons of the rat neostriatum, neocortex, and hippocampus using in situ hybridization. Tissue sections were hybridized with radiolabeled RNA probes for mGluR1 or mGluR5 and digoxygenin labeled RNA probes detecting somatostatin (SOM), preproenkephalin (ENK), preprotachykinin (SP), glutamic acid decarboxylase 67 (GAD67), parvalbumin (PARV), or choline acetyltransferase (ChAT) mRNA. In the striatum, mGluR1 hybridization signal was observed in all six neuronal populations. The strongest signal was found in SP-positive neurons, with a lower signal in ENK-positive neurons. All striatal interneurons were labeled less intensely than ENK- and SP-positive projection neurons. For striatal mGluR5 mRNA, both SP- and ENK-positive projection neurons were intensely labeled, but only GAD67-positive interneurons exhibited a significant signal. In the neocortex and hippocampus, mGluR1 and mGluR5 hybridization signals were studied in SOM-, GAD67-, and PARV-positive neurons. Hybridization signal for mGluR1 mRNA was intense in SOM-positive neurons of the cortex, CA1, CA3, and dentate gyrus, and weaker in GAD67-positive neurons of CA3 and dentate gyrus. MGluR5 signals were intensely labeled in SOM-, GAD67- and PARV-positive neuronal populations of the cortex and hippocampus. SOM-positive neurons were more intensely labeled in the hippocampus than cortex.

Cloning and stable expression of the mGluR1b subtype of human metabotropic receptors and pharmacological comparison with the mGluR5a subtype

We isolated and characterized a cDNA encoding the human metabotropic glutamate receptor subtype 1b (hmGluR1b). In situ hybridization studies in human brain regions revealed a higher distribution of mGluR1 mRNA in the dentate gyrus of the hippocampus, the substantia nigra pars compacta and the Purkinje cell layer of the cerebellum compared to other regions studied. We established stable expression of recombinant hmGluR1b in L(tk-) mouse fibroblast and Chinese hamster ovary (CHO-dhfr-) cells. In both expression systems, agonist activation of hmGluR1b stimulated inositol phosphate (InsP) formation and elevation of the cytosolic free calcium ([Ca2+]i), and both responses were blocked by (S)-MCPG. The rank order of potency for agonists was quisqualate > glutamate > (1S,3R)-ACPD in both expression systems. Comparison of the agonist profiles of hmGluR1b and hmGluR5a, both stably expressed in L(tk-) cells, indicated the same rank order of potency (quisqualate > glutamate > or = (RS)-3,5-DHPG > or = (1S,3R)-ACPD), but each of the four agonists were more potent on hmGluR5a than on hmGluR1b. In antagonist studies, (S)-MCPG inhibited the agonist-induced InsP formation and elevation of [Ca2+]i in both hmGluR1b- and hmGluR5a-expressing cells. (S)-4CPG and (S)-4C3HPG both inhibited agonist responses only in hmGluR1b-expressing cells. However, in hmGluR5a-expressing cells the antagonist activity of (S)-4CPG and (S)-4C3HPG was dependent on the agonist used in the study, since they inhibited responses to glutamate but not to quisqualate. Stable cell lines expressing specific subtypes of human mGluRs represent valuable tools for the study of the mechanism of action of mGluRs at the molecular and cellular level and as screening targets for identification of subtype-selective agonists or antagonists.

Clinical pathway for pediatric parenteral nutrition

The nutrition support team at Lucile Salter Packard Children's Hospital at Stanford developed a clinical pathway for infants and children receiving parenteral nutrition (PN). Use of clinical pathways for health care delivery is one way in which clinicians and institutions are responding to pressure from managed care organizations to reduce costs and maintain or improve quality. This pathway was developed to standardize the process for ordering, implementing, and monitoring PN. Specific goals for the pathway are as follows: to decrease the number of patients receiving PN inappropriately, to decrease the duration of PN for those patients who require it, to determine complication rates, and to monitor outcomes of therapy. Such comprehensive monitoring will help identify areas for improvement. By developing and implementing action plans to address these issues, we expect to improve continuously the processes and outcomes associated with PN therapy.

Expression of NMDAR2D glutamate receptor subunit mRNA in neurochemically identified interneurons in the rat neostriatum, neocortex and hippocampus

NMDA receptors are composed of proteins from two families: NMDAR1, which are required for channel activity, and NMDAR2, which modulate properties of the channels. The mRNA encoding the NMDAR2D subunit has a highly restricted pattern of expression: in the forebrain, it is found in only a small subset of cortical, neostriatal and hippocampal neurons. We have used a quantitative double-label in situ hybridization method to examine the expression of NMDAR2D mRNA in neurochemically defined populations of neurons. In the neostriatum, NMDAR2D was expressed by the interneuron populations marked by preprosomatostatin (SOM), the 67-kDa form of glutamic acid decarboxylase (GAD67), parvalbumin (PARV), and choline acetyltransferase (ChAT) mRNAs but not by the projection neurons expressing beta-preprotachykinin (SP) or preproenkephalin (ENK) mRNAs. In the neocortex, NMDAR2D expression was observed in only a small number of neurons, but these included almost all of the SOM-, GAD67-, and PARV-expressing interneurons. In the hippocampus, NMDAR2D was not present in pyramidal or granule cells, but was abundant in SOM-, GAD67-, and PARV-positive interneurons. NMDAR2D expression appears to be a property shared by interneurons in several regions of the brain. The unique electrophysiological characteristics conveyed by this subunit, which include resistance to blockade by magnesium ion and long channel offset latencies, may be important for the integrative functions of these neurons. NMDAR2D-containing receptor complexes may prove to be important therapeutic targets in human disorders of movement. In addition, the presence of NMDAR2D subunits may contribute to the differential vulnerability of interneurons to excitotoxic injury.

Formula allergy and intolerance

There are two major types of adverse reactions in infant formulas: (1) formula allergy/hypersensitivity, which is an immunologic response, and (2) formula intolerance, which is a nonimmunologic response. Formula intolerance can occur in infants with an underlying congenital or acquired enzyme deficiency (disaccharidase deficiency, galactosemia, hereditary fructose intolerance). The clinical presentation, diagnosis, and treatment of both reactions are reviewed in this article. The appropriateness of the use of a variety of infant formulas is discussed. Guidelines for the prevention of allergic disease are described as well.

Evolving asymmetric hypertrophic pyloric stenosis associated with histologic evidence of eosinophilic gastroenteritis

The most frequently occurring and important cause of gastric outlet obstruction in the neonate and young infant is infantile hypertrophic pyloric stenosis (IHPS). A reported association of IHPS and eosinophilic gastroenteritis [1] raises interesting questions about the possible etiologic relationship between the two entities. It is plausible that the observed sonographic pyloric muscular wall thickness in IHPS may in part be dependent on the degree and duration of an allergic gastroenteropathy. A recent report suggests that endoscopy may be a more reliable diagnostic method than sonography in the patient with evolving IHPS [2]. Our recent experience with a patient with evolving IHPS supports the findings described in these prior reports.

The effect of nutritional additives on anti-infective factors in human milk

It has become a common practice to supplement human milk with a variety of additives to improve the nutritive content of the feeding for the premature infant. Twenty-two freshly frozen human milk samples were measured for lysozyme activity, total IgA, and specific IgA to Escherichia coli serotypes 01, 04, and 06. One mL aliquots were mixed with the following: 1 mL of Similac, Similac Special Care, Enfamil, Enfamil Premature Formula, and sterile water; 33 mL of Poly-Vi-Sol, 33 mg of Moducal, and 38 mg of breast-milk fortifier, and then reanalyzed. Significant decreases (41% to 74%) in lysozyme activity were seen with the addition of all formulas; breast-milk fortifier reduced activity by 19%, while no differences were seen with Moducal, sterile water, or Poly-Vi-Sol. No differences were seen in total IgA content, but some decreases were seen in specific IgA to E. coli serotypes 04 and 06. E. coli growth was determined after 3 1/2 hours of incubation at 37 degrees C after mixing. All cow-milk formulas enhanced E. coli growth; soy formulas and other additives preserved inhibition of bacterial growth. Nutritional additives can impair anti-infective properties of human milk, and such interplay should be considered in the decision on the feeding regimen of premature infants.

Improved growth and disease activity after intermittent administration of a defined formula diet in children with Crohn's disease

Growth failure is the most common extraintestinal manifestation of Crohn's disease in childhood, occurring in up to 50% to 88% of affected patients. Previous studies have shown malnutrition to be the most likely cause of the decrease in height and weight velocities in these children. The purpose of this study was to determine the effect of an intermittent defined formula diet on growth and disease activity in children with Crohn's disease and growth failure. Six Tanner stage I-II patients, mean age 13.6 years with height less than the 5th percentile or height velocity less than the 3rd percentile were enrolled in a 1-year prospective study. An isotonic, hydrolyzed whey, medium-chain triglyceride formula was given by nocturnal nasogastric infusion at a caloric equivalent of 50th percentile for age, as the exclusive nutrient source 1 out of 4 months during a 1-year period. A 2-week exclusion diet and a 2-week low-residue diet followed the defined formula diet before resuming the regular diet for 2 months. Patients served as their individual control based on observations of at least 1 year before the study. Height and weight velocity significantly increased. Prednisone intake significantly decreased, and significant improvement was seen in disease activity, albumin, and somatomedin C. The results indicate that an intermittent defined formula diet can improve growth failure and significantly decrease disease activity in children with Crohn's disease.

Effects of microwave radiation on anti-infective factors in human milk

In intensive care nurseries it has become common practice to use microwave thawing of frozen human milk for more rapid accessibility. Twenty-two freshly frozen human milk samples were tested for lysozyme activity, total IgA, and specific secretory IgA to Escherichia coli serotypes 01, 04, and 06. The samples were heated by microwave for 30 seconds at a low- or high-power setting and then reanalyzed. One-mL aliquots of 10 additional human milk samples were microwaved at low (20 degrees C to 25 degrees C), medium (60 degrees C to 70 degrees C), and high (greater than or equal to 98 degrees C) setting before the addition to each of 1 mL of diluted E coli suspension. E coli growth was determined after 3 1/2 hours of incubation at 37 degrees C. Microwaving at high temperatures (72 degrees C to 98 degrees C) caused a marked decrease in activity of all the tested antiinfective factors. E coli growth at greater than or equal to 98 degrees C was 18 times that of control human milk. Microwaving at low temperatures (20 degrees C to 53 degrees C) had no significant effect on total IgA, specific IgA to E coli serotypes 01 and 04, but did significantly decrease lysozyme and specific IgA to E coli serotype 06. Even at 20 degrees C to 25 degrees C, E coli growth was five times that of control human milk. Microwaving appears to be contraindicated at high temperatures, and questions regarding its safety exist even at low temperatures.

Microvillous inclusion disease. The importance of electron microscopy for diagnosis

We report two cases of microvillous inclusion disease (MID) occurring in a set of siblings. Although it is a rare disorder, MID appears to be a common cause of familial intractable secretory diarrhea. Diagnosis rests on the ultrastructural finding of intracytoplasmic inclusions that are lined by intact microvilli. These inclusions are present in the absorptive surface epithelial cells of the small and large intestine and are associated with poorly developed surface brush border microvilli. The prognosis of MID is poor and curative therapy is not currently available. Because MID appears to be a hereditary disorder, genetic counseling of affected families is essential.

Anthropometry and bilirubin production

Anthropometric measurements and total bilirubin formation (TBF) estimates were performed on infants born to normal and diabetic mothers. Although we do not exclude the theoretical possibility of a low-frequency occurrence of increased TBF in macrosomic infants of normal mothers, we can conclude that infants of mothers whose diabetes is well managed may have normal TBF.