Gut-derived serotonin contributes to bone deficits in colitis.

Osteoporosis and bone fractures occur at higher frequency in patients with inflammatory bowel disease (IBD), and decreased bone mass is observed in animal models of colitis. Another consistent feature of colitis is increased serotonin (5-HT) availability in the intestinal mucosa. Since gut-derived 5-HT can decrease bone mass, via activation of 5-HT1B receptors on pre-osteoblasts, we tested the hypothesis that 5-HT contributes to bone loss in colitis. Colitis was chronically induced in mice by adding dextran sodium sulfate (DSS) to their drinking water for 21 days. At day 21, circulating 5-HT levels were elevated in DSS-inflamed mice. Micro-computed tomography of femurs showed a decrease in trabecular bone volume fraction, formation, and surface area, due largely to decreased trabecular numbers in DSS-treated mice. The colitis-induced loss of trabecular bone was significantly suppressed in mice treated with the 5-HT synthesis inhibitor, p-chloro-DL-phenylalanine (PCPA; 300 mg/kg/day IP daily), and in mice treated with the 5-HT1B receptor antagonist GR55562 (1 mg/Kg/day SC daily). The 5-HT reuptake transporter (SERT) is critical for moving 5-HT from the interstitial space into enterocytes and from serum into platelets. Mice lacking SERT exhibited significant deficits in trabecular bone mass that are similar to those observed in DSS-inflamed mice, and these deficits were not extensively worsened by DSS-induced colitis in the SERT-/- mice. Taken together, findings from both the DSS and SERT-/- mouse models support a contributing role for 5-HT as a significant factor in bone loss induced by colitis.

Altered gastrointestinal motility involving autoantibodies in the experimental autoimmune encephalomyelitis model of multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) is an autoimmune disease of the central nervous system that, in addition to motor, sensory, and cognitive symptoms, also causes constipation, which is poorly understood. Here, we characterize gastrointestinal (GI) dysmotility in the experimental autoimmune encephalomyelitis (EAE) mouse model of MS and evaluate whether autoantibodies target the enteric nervous system (ENS) and cause dysmotility. METHODS: EAE was induced in male SJL and B6 mice. GI motility was assessed in vivo and ex vivo in wild type (WT) and B cell-deficient mice. MS and EAE serum was used to survey potential targets in the ENS and changes in the ENS structure were characterized using immunohistochemistry. KEY RESULTS: EAE mice developed accelerated gastric emptying and delayed whole GI transit with reduced colonic motility. Fecal water content was reduced, and colonic migrating myoelectrical complexes (CMMC) and slow waves were less frequent. Colons from EAE mice exhibited decreased GFAP levels in glia. Sera from MS patients and from EAE mice targeted ENS neurons and glia. B-cell deficiency in EAE protected against colonic dysmotility. CONCLUSIONS & INFERENCES: Consistent with symptoms experienced in MS, we demonstrate that EAE mice widely exhibit features of GI dysmotility that persisted in the absence of extrinsic innervation, suggesting direct involvement of ENS neurocircuitry. The absence of GI dysmotility in B cell-deficient mice with EAE together with EAE and MS serum immunoreactivity against ENS targets suggests that MS could be classified among other diseases known to induce autoimmune GI dysmotility.

Pre-B acute lymphoblastic leukemia in a 3-year-old boy with pre-acute myelogenous leukemia myelodysplastic syndrome: cytogenetic evidence of common early progenitor cell ontogeny.

PURPOSE: Myelodysplastic syndromes in children commonly evolve into acute leukemia, usually acute myelogenous leukemia (AML) and rarely acute lymphoblastic leukemia (ALL). The lineage of the leukemia can be predicted based on characteristic morphologic and cytogenetic findings of the marrow and peripheral blood. PATIENT AND METHODS: A 3-year-old boy had refractory anemia with excess blasts and abnormalities suggestive of pre-AML with highly unusual cytogenetic changes. ALL of pre-B phenotype developed. RESULTS: Leukoerythroblastic anemia, pseudo Pelger-Huet neutrophils, and dysmyelopoietic hyperplasia of the marrow suggested likely early progression to AML. Complex cytogenetic abnormalities (monosomy 17 and 20, ring chromosome 11 with deletion of bands q23, and a derivative dicentric chromosome 12) were present in both the myelodysplastic marrow and the subsequent ALL. CONCLUSION: This case presents cytogenetic evidence of common early progenitor cell ontogeny of both malignancies (refractory anemia with excess blasts and ALL).

Acceptance of amniocentesis by women in the state of Montana (USA) who are screen positive for Down's syndrome.

OBJECTIVE: To assess factors influencing uptake of amniocentesis after a positive Down's syndrome screening result. METHODS: Interviews of 53 Montana women with screening risks > or = 1 in 300 after delivery. RESULTS: Thirty had accepted amniocentesis ("yes" group) and 23 had declined ("no" group) (57% uptake). Age at delivery was significantly higher (p = 0.02) for the "no" than the "yes" group (mean 35.3 nu 31.7 years). The mean risk of Down's syndrome ascertained by screening was 1 in 190 for the "no" group and 1 in 115 for the "yes" group (p = 0.05). Statistically significant differences (p < or = 0.05) between opinions in the two groups included: (a) desire to know if the fetus had Down's syndrome; (b) perception of the burden of care for an affected child; (c) support of doctor, spouse, and relatives for choice about amniocentesis; (d) attitudes toward abortion; (e) importance of religion; and (f) concerns about the amniocentesis procedure. The most important factor for those choosing amniocentesis was knowing if the fetus had Down's syndrome, and for those not choosing amniocentesis, attitude about abortion. CONCLUSION: Our results show the need for prescreening education to enable pregnant women to make informed decisions about screening for Down's syndrome and diagnostic testing.

Fanconi anemia in brothers initially diagnosed with VACTERL association with hydrocephalus, and subsequently with Baller-Gerold syndrome.

Two brothers with presumed Baller-Gerold syndrome, one of whom was previously diagnosed with the association of vertebral, cardiac, renal, limb anomalies, anal atresia, tracheo-esophageal fistula (VACTERL) association with hydrocephalus, were evaluated for chromosome breakage because of severe thrombo cytopenia in one of them. Spontaneous and clastogen-induced breakage was markedly increased in both patients as compared to control individuals. Clinical manifestations and chromosome breakage, consistent with Fanconi anemia, in patients with a prior diagnosis of either Baller-Gerold syndrome, reported earlier in one other patient [Farrell et al., 1994: Am J Med Genet 50:98-99], or with VACTERL association with hydrocephalus, recently reported in 3 patients [Toriello et al., 1991: Proc Greenwood Genet Center 11:142; Porteus et al., 1992: Am J Med Genet 43:1032-1034], underline the clinical heterogeneity of Fanconi anemia and raise the question of whether these syndromes are distinct disorders or phenotypic variations of the same disease.

Reverse transformation and genome exposure in the C6 glial tumor cell line.

Reexpression of growth control and differentiation in response to physiological inducers can be demonstrated in some malignant cell lines, showing that they are not irreversibly transformed. This switch in phenotype is likely to reflect a changing pattern of gene expression, but it has not been known whether such cellular transitions involve major or only minor modulation of chromatin structure. We have studied growth control and accessibility of chromatin to DNase I in C6 glioma cells subjected to different growth regimens using an in situ nick translation assay to label the most exposed regions of nuclear chromatin. In fibroblasts and primary glia, exposed chromatin was localized mainly at the nuclear lamina. This readily labeled DNA structure was largely lacking in the malignant C6 glioma. When C6 cells were treated with dibutyryl cyclic AMP, exposed chromatin was reestablished around the nuclear periphery. This restoration of a normal genome exposure pattern required cytoskeletal integrity. Thus large-scale nuclear reorganization events proceed in parallel with phenotypic normalization. The changes in cell morphology, growth control, cytoskeletal organization, and chromatin exposure and localization are similar to the reverse transformation reaction in CHO-K1 cells, which is also regulated by the cyclic nucleotide system. Hydrocortisone and dexamethasone also restored genome exposure in C6 but less markedly than cAMP derivatives. Diverse transformed cells can thus respond to growth control stimuli with similar nuclear restructuring events, which presumably underlie changes in gene expression. Reverse transformation and redifferentiation appear to be alternative terms describing essentially the same biological phenomenon.

Clonal sublines of rat neurotumor RT4 and cell differentiation. VI. Chromosome analysis.

The RT4 neurotumor cell system consists of clonally derived cell lines where a stem cell type segregates in vitro into three biochemically and morphologically different cell types, one glial and two neuronal types. This process has been termed cell-type conversion (M. Imada and N. Sueoka, 1978, Dev. Biol. 66, 97-108). Detailed cytogenetic analysis of the RT4 cell lines are described. Giemsa-banding analysis of 12 independent clonal isolates of the four different RT4 cell types showed a relatively stable karyotype. The stem cell line, RT4-AC, is diploid and most stable, and it has one 4q+ marker chromosome in place of a normal No. 4. This 4q+ marker was identified in all cell types of the RT4 system and was not observed in other cell lines of BDIX origin. The 4q+, therefore, is a chromosomal marker of the RT4 system. Consistent chromosome rearrangement was not found in any one of the cell-type conversions of the RT4-AC cells into the three derivative cell types. The relative stability of the karyotype of the different clonal isolates gives the RT4 system an advantage in studies of genetic regulation and expression of cell-type conversion in vitro. Also the 4q+ marker can be used to identify RT4 cells in coculture experiments or to distinguish RT4 cells in cases of suspected cell-line contamination.

Association of chromosome 4 abnormalities with ethylnitrosourea-induced neuro-oncogenesis in the rat.

Cytogenetic studies of rat neurogenic tumor lines induced by ethylnitrosourea (ENU) have shown specific involvement of chromosome 4. The study reported here further characterizes the association of chromosome 4 abnormalities in rat tumor cell lines with regard to etiological agent, tissue of origin, and tumorigenic potential of cloned lines. Lines from rat gliomas induced by avian sarcoma virus did not show abnormalities of chromosome 4. ENU-induced rat tumors of nonneurogenic origin had numerical and/or structural abnormalities of chromosome 4 in seven of nine cell lines. In a comparison of two tumorigenic and two nontumorigenic cloned cell types from the same ENU-induced rat neural tumor, all showed excess chromosome 4. In addition, preneoplastic nervous system tissue, exposed to ENU in vivo, was cultured and sequentially monitored for the concurrent development of chromosome abnormalities and neoplastic properties. Abnormalities of chromosome 4 were observed in 3 of 14 tumorigenic lines and one nontumorigenic clone. The remaining lines had normal karyotypes or abnormalities involving chromosomes other than chromosome 4. Our results suggest that chromosome 4 abnormalities appear late in tumor development, are probably secondary to the tumorigenic potential of the studied cell lines, and apparently are not tissue specific. However, abnormalities of chromosome 4 may be associated preferentially with ENU oncogenesis.

Chromosome analysis of a human neuroblastoma.

Samplings of tumor cells from a patient with Stage IV neuroblastoma were analyzed for chromosome constitution. Chromosome preparations of the tumor cells from a bone marrow sample were compared to preparations of a solid metastatic tumor after growth in the nude mouse host or followed by culture. Six separate chromosome studies were done. The tumor karyotype demonstrated an overall stability, maintaining the consistent abnormalities of a 1p-, +17, and -22. Chromosomes 5 and 9 were also involved in structural abnormalities in sublines of the tumor cells. Double minutes were seen in all preparations.