Selective demonstration of mural nerves in ganglionic and aganglionic colon by immunohistochemistry for glucose transporter-1: prominent extrinsic nerve pattern staining in Hirschsprung disease

OBJECTIVE: Hypertrophic nerves have long been considered a histopathologic feature of the aganglionic segment in Hirschsprung disease, but they remain incompletely explained. The purpose of this study was to define the nature and diagnostic importance of hypertrophic nerves in Hirschsprung disease and to clarify their relation to nearby smaller nerve fibers. METHODS: We used an immunoperoxidase staining technique to compare the distribution of 2 nerve markers-erythrocyte-type glucose transporter (GLUT-1), a marker of perineurium, and nerve growth factor receptor, a marker of both nerve fibers and perineurium-in aganglionic tissue (12 resected specimens and 4 rectal biopsies) and control tissue (6 autopsy specimens and 17 rectal biopsies) of children. RESULTS: In control ganglionic tissue, the myenteric and submucosal areas contained only occasional GLUT-1-positive nerves (usually less than 50 microm in diameter), but extramural extrinsic (serosal) nerves were invariably positive for GLUT-1. In aganglionic tissue, GLUT-1-positive nerves in the myenteric and submucosal areas were frequent and included both large (50-150 microm) and small (<50 microm) diameter nerves. Nerve growth factor receptor-positive fibers were frequent in all layers of all tissue studied. In aganglionic bowel, a distinct perineurium could be identified in the largest nerves, but nerve growth factor receptor had poor discrimination for small perineurium-sheathed nerves. CONCLUSION: Most nerves, of both large and small diameter, in the myenteric and submucosal plexus of aganglionic bowel are GLUT-1 positive. Serosal extrinsic nerves stain identically, supporting the interpretation that the mural nerves are of extrinsic origin. Mural GLUT-1-positive nerves, when they are multiple and especially when they are greater than 50 microm in diameter (a figure which may be used as a threshold for hypertrophic nerves), are suggestive of Hirschsprung disease.     

A mathematical model of optimized radioiodine-131 therapy of Graves' hyperthyroidism

Background

The current status of radioiodine-131 (RaI) dosimetry for Graves' hyperthyroidism is not clear. Recurrent hyperthyroidism and iatrogenic hypothyroidism are two problems which interact such that trying to solve one leads to exacerbation of the other. Optimized RaI therapy has therefore begun to be defined just in terms of early hypothyroidism (ablative therapy) as physicians have given up on reducing hypothyroidism.

Methods

Optimized therapy is evaluated both in terms of the greatest separation of cure rate from hypothyroidism rate (non-ablative therapy) or in terms of early hypothyroidism (ablative therapy) by mathematical modeling of outcome after radioiodine and critically discussing the three common methods of RaI dosing for Graves' disease.

Results

Cure follows a logarithmic relationship to activity administered or absorbed dose, while hypothyroidism follows a linear relationship. The effect of including or omitting factors in the calculation of the administered I–131 activity such as the measured thyroid uptake and effective half-life of RaI or giving extra compensation for gland size is discussed.

Conclusions

Very little benefit can be gained by employing complicated methods of RaI dose selection for non-ablative therapy since the standard activity model shows the best potential for cure and prolonged euthyroidism. For ablative therapy, a standard MBq/g dosing provides the best outcome in terms of cure and early hypothyroidism.     

Effects of interferon in malaria infection

Earlier, we reported that prophylactic treatment with human interferon gamma (rHuIFN-gamma) protected monkeys against Plasmodium cynomolgi B malaria infection. We have tested the efficacy of rHuIFN-gamma on relapsing stage of experimental P. cynomolgi B malaria infection in rhesus monkeys. No effect of rHuIFN-gamma was seen against experimental relapsing stage compared with controls; however, it appears that chloroquine (CHL) may have interfered with the antimalarial effect of IFN, since treatment with CHL inhibits the antiviral activity of mouse alpha/beta IFN and polyinosinic-polycytidylic acid (poly I:C) against Semliki forest virus (SFV) in mice. These results may have clinical implications especially with the use of IFN against virus infection, cancer and in parasitic infections in malaria endemic areas where CHL is one of the most widely used antimalarial drugs. Our result also shows that CHL treatment enhances the virus replication in mice and suggest a possible connection between AIDS and malaria infection, since the spread of AIDS has been rapid in parts of tropical Africa that have a high incidence of malaria, and chloroquine has been frequently used in the chemotherapy of malaria.     

Expression of high-affinity IL-4 receptors on murine tumour infiltrating lymphocytes and their up-regulation by IL-2.

Since interleukin-2 (IL-2) and IL-4 act in concert to support the development of cytotoxic T lymphocytes (CTL) and the generation of antigen-specific tumour infiltrating lymphocytes (TIL), we investigated the interaction of these cytokines with an established TIL line. TIL proliferated in an additive fashion in response to suboptimal concentrations of IL-2 and various concentrations of IL-4. TIL possessed high-affinity IL-4 receptors whether cultured in recombinant IL-2 (rIL-2) or rIL-4, but cells cultured in rIL-2 had higher numbers of IL-4 receptors than cells cultured in rIL-4. When TIL were cultured in increasing concentrations of rIL-2, a dose-dependent enhancement in IL-4 receptor number was observed. The maximum induction of IL-4 receptor expression was achieved by 4 hr of incubation with rIL-2 and was completely blocked by cycloheximide. Other cytokines, such as rIL-1, recombinant tumour necrosis factor (rTNF), recombinant interferon-alpha (rIFN-alpha) and rIFN-gamma, had no effect on IL-4 receptor number. rIL-2 also up-regulated IL-4 receptors on CTLL-2, a murine CTL line. These data indicate that high-affinity IL-4 receptors exist on murine TIL and they can be up-regulated by IL-2. Our observation that IL-2 up-regulates IL-4 receptor may help explain the additive effects of these lymphokines on the proliferation of TIL and other cell lines. It may also help explain their co-operative effects on the generation of antigen-specific TIL and the differentiation of CTL.     

Complete Nucleotide Sequence Analysis of a Western Pacific Dengue-1 Virus Strain

We have determined the complete nucleotide sequence and the deduced amino acid polypeptide sequence of the genome of a dengue-1 (DEN-1) virus strain isolated from a patient on Nauru in the Western Pacific in 1974 (West Pac 74). The complete genome is 10,735 nucleotides in length and contains a single long open reading frame of 10,176 nucleotides encoding a polyprotein of 3392 amino acids. When compared to DEN-1 Singapore S275/90, the nucleotide and amino acid sequence homology are 94% and 97.8%, respectively. This revised version was published online in July 2006 with corrections to the Cover Date.     

Identification and characterization of aquaporin-2 water channel mutations causing nephrogenic diabetes insipidus with partial vasopressin response

Congenital nephrogenic diabetes insipidus (NDI) is a rare disease caused most often by mutations in the vasopressin V2 receptor (AVPR2). We studied a family which included a female patient with NDI with symptoms dating from infancy. The patient responded to large doses of desmopressin (dDAVP) which decreased urine volume from 10 to 4 I/day. Neither the parents nor the three sisters were polyuric. The patient was found to be a compound heterozygote for two novel recessive point mutations in the aquaporin-2 (AQP2) gene: L22V in exon 1 and C181W in exon 3. Residue Cys181 in AQP2 is the site for inhibition of water permeation by mercurial compounds and is located near to the NPA motif conserved in all aquaporins. Osmotic water permeability (Pf) in Xenopus oocytes injected with cRNA encoding C181W-AQP2 was not increased over water control, while expression of L22V cRNA increased the Pf to approximately 60% of that for wild-type AQP2. Co-injection of the mutant cRNAs with the wild-type cRNA did not affect the function of the wild-type AQP2. Immunolocalization of AQP2-transfected CHO cells showed that the C181W mutant had an endoplasmic reticulum-like intracellular distribution, whereas L22V and wild-type AQP2 showed endosome and plasma membrane staining. Water permeability assays showed a high Pf in cells expressing wild-type and L22V AQP2. This study indicates that AQP2 mutations can confer partially responsive NDI.      

Reciprocal effect of Waardenburg syndrome mutations on DNA binding by the Pax-3 paired domain and homeodomain

The Pax-3 protein contains two DNA-binding domains, a paired domain and a homeodomain. Mutations in Pax-3 cause Waardenburg syndrome (WS) in humans and the mouse Splotch (Sp) phenotype. In the Sp-delayed mouse, a mutation in the Pax-3 paired domain (G9R) abrogates the DNA-binding activity of both the paired domain and the homeodomain, suggesting that they may functionally interact. To investigate this possibility further, we have analyzed the DNA-binding properties of additional point mutants in the Pax-3 paired domain and homeodomain that occur in WS patients (F12L, N14H, G15S, P17L, R23L, G48A, S51F and G66D in the paired domain, V47F and R53G in the homeodomain), the Pax-1 un mutation (G15A) and a substitution associated with Peters' anomaly in the PAX-6 gene (R23G). Within the paired domain, seven of 10 mutations were found to abrogate DNA-binding by the paired domain. Remarkably, these seven mutations also affected DNA binding by the homeodomain, causing either a complete loss (P17L and G66D), a reduction (R23G, R23L, G15S and G15A) or an increase in DNA-binding activity (N14H). In addition, the effect of paired domain mutations occurred at the level of monomer formation by the homeodomain, while the dimerization potential of this domain seemed unaffected in mutants where it could be analyzed. Furthermore, while both homeodomain mutations were found to abolish DNA binding by this domain, the R53G mutation also abrogated DNA binding by the paired domain. The important observation that independent mutations in either domain can affect DNA binding by the other in the intact Pax- 3 protein strongly suggests that the two domains are not functionally independent but bind DNA through cooperative interactions. Modeling the deleterlous mutations on the three-dimensional structure of the paired domain of Drosophila Prd shows that these mutations cluster at the DNA interface, thus suggesting that a series of DNA contacts are essential for DNA binding by both the paired domain and the homeodomain of Pax-3.      

Pulmonary edema in renal transplant patients

A syndrome heralded by fever, deterioration of graft function, respiratory failure accompanied by pulmonary infiltrates has been termed "transplant lung." We hemodynamically studied eight such patients. At the height of their illness, pulmonary artery wedge pressure (PAWP) was elevated to 19.3 +/- 2.6 mm Hg along with mean pulmonary artery pressure (PAP) of 35.0 +/- 3.8 mm Hg in presence of increased cardiac index (CI) of 4.9 +/- 0.9 L.m2.min. Pathophysiology of pulmonary edema appears to include high left ventricular filling pressures, pulmonary hypertension, alterations of oncotic hydrostatic gradient, and increased cardiac output. A partial reversal of pulmonary hypertension was observed with dialysis or diuresis. Our data suggest incipient renal failure and fluid accumulation as the etiology of hemodynamic pulmonary edema in "transplant lung."