Hirschsprung's disease: genetic mutations in mice and men

MRC Brain Development Programme,Department of Developmental Neurobiology,UMDS Guy's Hospital,London SE1 9RT, UK

S HALL

Hirschsprung's disease is a neuronal dysplasia of the hindgut,characterised by a loss of neurones, which affects about 1in 5000 livebirths.1 Genetic factors have been implicated in theaetiology of this disease in about 20% of cases and a dominant patternof inheritance has been revealed in several families. The pathogenesis of the aganglionosis is often attributed to a failureof migration of neural crest cells, although this has not been proven.
Recently, mutations in a developmentally regulated receptor tyrosinekinase gene, ret, and mutations in the endothelinreceptor-B gene (ENDR-B) have both been linked to familialHirschsprung's disease in humans.4-6 Moreover, certainmutant mouse strains—namely piebald lethal and lethal spotted—exhibitstriking similarities to the human condition. The mutation which givesrise to piebald lethal has now been found to be in the ENDR-Bgene,7 and the mutation associated with lethal spottedoccurs in the gene for endothelin-3 (ET-3), a ligand forENDR-B.8
Two transgenic mouse lines have been developed which also reflect thehuman disease: ret-k , which has aloss of function mutation of the retgene,9 and ENDR-B null.10 In addition, theintroduction of a Lac-Z reporter gene into neural crest cells ofaganglionic mice has made it possible to study directly the fate ofenteric neuroblasts which are affected by "Hirschsprung's-like"mutations.11 Here, we review the possible roles of RET andendothelin in the normal development of the enteric nervous system, andthe significance of their mutated forms in the pathogenesis of familialaganglionosis.
This review focuses on recent advances in our understanding of thegenetic basis of the lesions which have been implicated in congenitalforms of Hirschsprung's disease. Disruption of these genes in themouse, either by transgenic "knockout" approaches or in mutantmouse lines, offers the prospect of greater understanding of both thecellular and developmental bases of the human disease.

     

大肠癌免疫组化表达与临床病理的关系

目的:探讨大肠癌CEA、P53、nm23、Ki-67、MRP免疫组化表达特点和相互关系,及其与临床病理的关系．方法:回顾性分析2003-01／2006-07我院收治的73例大肠癌患者的临床病理及随访资料,并对其石蜡标本采用免疫组化SP染色法检测CEA、P53、nm23、Ki-67、MRP,分析其免疫组化特点及其与临床病理之间的关系．结果:CEA、P53、nm23、Ki-67、MRP在大肠癌中的阳性表达率依次为82．2％、68．5％、75.3％、84．9％和64．4％．CEA、MRP与大肠癌患者的各因素无统计学差异．P53、Ki-67和nm23与肿瘤的Dukes分期和淋巴结转移有关, P53、Ki-67在Dukes C、D期的阳性表达率(依次为82．8％和100％1明显高于Dukes A、B期者(59．1％和75．0％)(P<0．05),而nm23在Dukes C、D期的阳性表达率(58．6％)明显低于Dukes A、B期者(86．4％)(P<0．05)．CEA与nm23的表达呈明显的负相关(r=-0．296,P=0．011),而P53和Ki-67表达之间呈现明显的正相关(r= 0．308,P=0．008),其他各指标间的表达无相关性．nm23、P53和Ki-67与预后因素关系明显,nm23在生存期≥3 a患者的阳性表达率(92．9%)高于生存期<3 a者(71．2％)(P<0．05),而P53和Ki-67在生存期≥3 a患者的阳性表达率(依次为42．9％和64.3％)明显低于生存期<3 a者(74．6％和89．8％)(P<0．05)．结论:P53、Ki-67和nm23的表达与大肠癌的侵袭转移和预后密切相关．CEA可能是大肠癌的侵袭转移的促进因素．MRP所引起的耐药机制是一个相对独立的机制．CEA、P53、nm23、Ki-67可作为判断大肠癌恶性程度、侵袭转移以及预后的指标．     

Combination chemotherapy (M-2) protocol (BCNU, cyclophosphamide, vincristine, melphalan, and prednisone) for Waldenstrom macroglobulinemia: preliminary report

Fourteen consecutively referred, symptomatic patients with Waldenstrom's macroglobulinemia (ages 52-87 yr) have been treated with the 5-drug M-2 protocol (BCNU, cyclophosphamide, vincristine, melphalan, and prednisone). Three patients were previously treated and 11 patients were untreated. The majority of patients were symptomatic from hyperviscosity. All patients have responded to therapy. Two patients have achieved complete remissions and 12 patients partial remissions to date. None of the patients with symptomatic hyperviscosity has required plasmapheresis since therapy with the M-2 has been initiated. Lymphadenopathy, hepatosplenomegaly, and anemia have also responded to treatment. Follow-up data are limited, with survival from initiation of therapy with the M-2 ranging from 2+ to 35% mo (median 17+ mo) 2+-40+ mo from time of diagnosis). Combination chemotherapy for Waldenstrom's macroglobulinemia with the M-2 protocol appears to increase the response rate in patients with symptomatic disease. Further survival analysis will be carried out.     

Acute leukemia associated with the t(4;11) chromosome rearrangement: ultrastructural and immunologic characteristics

The acute leukemia associated with the t(4;11) chromosome rearrangement is characterized by relatively consistent clinical features: occurrence primarily in young individuals, hyperleukocytosis, and poor response to therapy. This study describes the morphological, ultrastructural, and immunologic characteristics of the leukemic cells from ten patients with this type of leukemia. The morphological features of the leukemic blasts vary from lymphoid-appearing to monocytic. Ultrastructurally and cytochemically, some of the lymphoid-appearing blasts possess features of myeloid origin. The immunologic phenotype is characteristically E- SIg- CALLA- BA-1- BA-2+ HLA-DR+ and TdT+. These findings suggest that the t(4;11)-associated acute leukemia represents a proliferation of an early myeloid progenitor cell.     

Acquired immunodeficiency syndrome-associated non-Hodgkin's lymphomas and other malignancies in patients with hemophilia

Non-Hodgkin's lymphoma (NHL) is the most common human immunodeficiency virus (HIV)-associated malignancy in hemophiliacs. We studied the incidence and clinicopathologic features of NHL in 3,041 hemophiliacs followed at 18 US Hemophilia Centers between 1978 and 1989. Of the 1,295 (56.6%) who were HIV(+), 253 (19.5%) developed acquired immunodeficiency syndrome (AIDS), of whom 14 (5.5%) developed NHL. Three NHL occurred in HIV(-) hemophiliacs, for a 36.5-fold greater risk in HIV(+) than HIV(-) hemophiliacs (P < .001). The NHL incidence rate was 29-fold greater than in the US population by Surveillance, Epidemiology, and End Results (SEER) estimates (P < .001). Between 0 and 4 lymphomas have been observed per year between 1978 and 1989. At presentation 13 (92.9%) of the HIV(+) NHL were extranodal. Ten were stage IV, 1 stage II, and 3 stage IE. Ten (71.4%) were high-grade, 3 (21.4%) intermediate-grade, and 1 (7.1%) was a low-grade B-cell lymphoma. Epstein-Barr virus (EBV) DNA was detected in 36% by in situ hybridization, including one central nervous system (CNS) lymphoma. The mean CD4 cell count at NHL diagnosis was 64/mm3, the mean latency from initial HIV infection was estimated to be 59 months, and the median survival was 7 months. The incidence of basal cell carcinoma in HIV(+) hemophiliacs was 18.3-fold greater than in HIV(-) hemophiliacs (P < .001) and 11.4-fold greater than in the US population (P < .001). In conclusion, incidence rates of NHL and basal cell carcinoma in HIV(+) hemophiliacs are significantly increased over rates in HIV(-) hemophiliacs and over rates in the US population. Clinicopathologic presentation of NHL in HIV(+) hemophiliacs is similar to that in HIV(+) homosexual men.     

Antibody responses to a 33 kDa cysteine protease of Trypanosoma congolense: relationship to 'trypanotolerance' in cattle

A cysteine protease of Trypanosoma congolense (congopain) elicited IgG1 antibodies in those cattle which exhibited a degree of resistance to disease during experimental infections (Authié et al. 1992, 1993). The aim of the present study was to investigate further the association between anti-congopain antibodies and resistance to trypanosomiasis, and to provide a lead into the mechanisms responsible for the differential responses to congopain in cattle. Isotype characteristics and kinetics of the antibody response to congopain were studied in three N'Dama (trypanoresistant) and three Boran (susceptible) cattle during primary infection with T. congolense ILNat 3.1. In both groups an IgM response to congopain was elicited, thus demonstrating that congopain is antigenic in both types of cattle. Most of the IgM appeared to be incorporated into immune complexes. IgG was detected as free antibody; IgG1 but not IgG2 was detected. All three N'Dama, but none of the three Boran cattle, mounted a significant IgG response to congopain. Sera from 70 primary-infected cattle belonging to five breeds of differing susceptibility were tested for their reactivity to congopain. High levels of IgG to congopain were observed in the two trypanotolerant breeds, whereas the three susceptible breeds had lower levels of these antibodies. Crosses between N'Dama and Boran cattle, which exhibit an intermediate susceptibility, had intermediate levels of antibodies. Thus, the results from experimental infections confirmed our initial observations. However, under natural tsetse challenge, repeated infections and trypanocidal treatments in Zebu cattle stimulated as high anti-congopain antibody levels as in non-treated trypanotolerant taurine cattle.     

Beta 2-integrin and L-selectin are obligatory receptors in neutrophil aggregation [see comments]

We have recently found that antibodies to L-selectin, the homing receptor on neutrophils, are as effective as those to beta 2-integrin at blocking formyl peptide-stimulated aggregation. Therefore, we investigated the requirements for expression of L-selectin and beta 2- integrin on adjacent cells during aggregation. Fluorescence flow cytometry allowed characterization of aggregates on the basis of size and color, as well as antibody binding to these two adhesive molecules. Formyl peptide-stimulated aggregate formation was measured for individual populations fluorescently labeled red (LDS-751) or green (CD44-FITC), and interpopulation red-green cell conjugates. Blocking either the beta 2-integrin or L-selectin adhesive epitope with monoclonal antibody on individual cell populations resulted in an approximately 50% reduction in two-color aggregation as compared with that in unblocked samples. Shedding the L-selectin on a cell population by preincubation with complexes of lipopolysaccharide and its plasma membrane binding protein also decreased aggregation to a control population by approximately 50%. We examined the aggregation of neutrophils from patients genetically deficient in beta 2-integrin and clinically leukocyte adhesion deficient (LAD). LAD adhesion to normal neutrophils was dependent on the expression of L-selectin on LAD cells and beta 2-integrin on normal cells. Thus, the minimum requirement for adhesion between two mixed populations of neutrophils was that one population expressed the beta 2-integrin and the other expressed the L- selectin adhesive epitope.     

THE PITUITARY-LEYDIG CELL AXIS IN MEN WITH SEVERE DAMAGE TO THE GERMINAL EPITHELIUM

Eighteen men (mean age 27, range 18-30 years) treated for Hodgkin's disease with 6-8 courses of MVPP (Mustine, Vinblastine, Procarbazine and Prednisolone) have had Leydig cell function assessed by their steroidogenic responses to stimulation by a single bolus dose of HCG (1000 units intramuscularly). Normal age-matched men (n = 16) acted as controls. Baseline immunoreactive FSH was markedly raised in the patients (mean 18.1 +/- SD 6.9 vs 2.0 +/- 1.5 IU/l, P less than 0.0001) reflecting damage to the germinal epithelium. Immunoreactive LH was also greater in patients (10.3 +/- 3.9 IU/l) than in controls (3.9 +/- 1.9 IU/l, P less than 0.0001). There were no differences between the baseline testosterone, androstenedione, oestradiol, oestrone and sex hormone binding globulin (SHBG) concentrations. The testosterone/SHBG ratios were similar in the two groups and there was no correlation between baseline LH and testosterone concentrations or testosterone/SHBG ratios. Testosterone, androstenedione, oestradiol and oestrone secretion in response to HCG stimulation were similar at 24 h and 96 h in both groups. In order to explain the paradox of elevated immunoreactive LH in the face of normal testicular steroidogenesis in such patients, LH biological activity (B) as well as LH immunoreactivity (I) and FSH and testosterone were estimated in a second similar group of patients (n = 17, mean age 27, range 17-43 years) and in a further age-matched control group (n = 17). Bioactive and immunoreactive LH levels were significantly increased (P less than 0.005 and P less than 0.001, respectively) in the patient group.(ABSTRACT TRUNCATED AT 250 WORDS)