Detection of a novel nonsense mutation of the MEN1 gene in a familial multiple endocrine neoplasia type 1 patient and its screening in the family members

We identified a novel nonsense mutation(R29X) of the MEN1 gene in a familial multiple endocrine neoplasia type 1 (MEN1) patient. Molecular analysis of the MEN1 gene was performed in the family members by a restriction digestion method. The same mutation pattern was seen in both the proband's younger brother and cousin diagnosed as MEN1, and was also observed in the son of the cousin who showed signs of normal levels of serum PTH associated with mild hypercalcemia and hypophosphatemia. These findings suggest that mutation analysis of the MEN1 gene is very useful in identifying the subclinical state of MEN1 as well as clinical MEN1.

Inhibitory effects of rebamipide on ENNG-induced duodenal carcinogenesis in mice: a possible strategy for chemoprevention of gastrointestinal cancers

Rebamipide is a potent antioxidative agent; it increases gastric mucosal PGE2 production and thus protects the gastric mucosa. We hypothesized that the mechanisms of ulcer formation could be extended to carcinogenesis and that an increase in gastric mucosal protection may result in a decrease in gastric carcinogenesis. Therefore, we assessed the inhibitory effects of rebamipide on N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) -induced carcinogenesis in mice. The percentage of tumor-bearing mice in three treatment groups--ENNG + rebamipide 20 mg, ENNG + rebamipide 50 mg, and ENNG alone--was 55%, 42%, and 67%, respectively. The incidence of tumorigenesis tended to decrease with increasing doses of rebamipide. The difference between ENNG + rebamipide 50 mg and ENNG alone was statistically significant (P < 0.05). These results suggest that rebamipide may strengthen the host defense mechanisms related to carcinogenesis in the digestive tract.

The gene structure and organization of mouse PG-Lb, a small chondroitin/dermatan sulphate proteoglycan

PG-Lb was originally characterized as a small chondroitin/dermatan sulphate proteoglycan expressed preferentially in the zones of flattened chondrocytes in developing chick limb cartilage. The occurrence of this proteoglycan in mammalian cartilage has been shown by the isolation of a cDNA clone from mouse cartilage cDNA library [Kurita, Shinomura,Ujita, Zako, Kida, Iwata and Kimata (1996) Biochem. J. 318, 909-914]. To understand the regulation mechanisms for such a unique expression, we have investigated a genomic DNA structure of the PG-Lb gene. The gene is composed of seven exons and six introns spanning more than 50 kb. The leucine-rich repeats are encoded from exon V to exon VII. The transcription initiation site has been determined by rapid amplification of the cDNA ends ('5'-RACE'). The possible TATA box was detected about 90 bp upstream of the adenosine residue that was numbered as position +1. Further analyses of 1.5 kb of the 5' flanking region and 2.2 kb of the first intron have revealed several potential binding motifs for transcription factors such as Sox 5 and 9. The presence of those sequences in the PG-Lb gene was discussed in relation to the unique expression of this proteoglycan. The chromosomal localization of the murine PG-Lb gene was determined to be on the mouse chromosome 10 by the fluorescence-in-situ-hybridization ('FISH') method.

Atrial septal displacement for repair of anomalous pulmonary venous return into the right atrium

BACKGROUND

In the repair of anomalous connection of the pulmonary veins to the right atrium, the use of a baffle of pericardium to divert the pulmonary venous blood into the left atrium could cause pulmonary venous obstruction as a result of thickening of the pericardial patch. Anomalous pulmonary venous drainage to the right atrium caused by malposition of the atrial septum primum can be repaired by displacing the shifted septum primum to the normal position.

METHODS

In 5 patients with total (n=2) or partial (n=3) anomalous pulmonary venous drainage into the right atrium, the septum primum was shifted toward the left atrium and the pulmonary veins drained into the anatomic right atrium despite their normal connection with the posterior wall of the left atrium. This method consisted of incision of the posterior edge of the atrial septum primum and displacement of the incised atrial septum between the anomalous pulmonary veins and both venae cavae. No patch was used.

RESULTS

Postoperative echocardiography showed a wide pathway from the pulmonary veins to the left atrium with no stenotic portions. No atrial arrhythmias occurred after the operation.

CONCLUSIONS

This technique may be advantageous because it allows for future growth of the route of the pulmonary venous pathway and avoids postoperative supraventricular arrhythmias.

Alpha1-syntrophin has distinct binding sites for actin and calmodulin

Overlay and co-sedimentation assays using recombinant alpha1-syntrophin proteins revealed that two regions of alpha1-syntrophin, i.e. aa 274-315 and 449-505, contain high-affinity binding sites for F-actin (Kd 0.16-0.45 microM), although only a single high-affinity site (Kd 0.35 microM) was detected in the recombinant full-length syntrophin. We also found that actomyosin fractions prepared from both cardiac and skeletal muscle contain proteins recognized by anti-syntrophin antibody. These data suggest a novel role for syntrophin as an actin binding protein, which may be important for the function of the dystrophin-glycoprotein complex or for other cell functions. We also found that alpha1-syntrophin binds calmodulin at two distinct sites with high (Kd 15 nM) and low (Kd 0.3 microM) affinity.

Increased expression of proliferating cell nuclear antigen in autoimmune hepatitis in a patient with raised serum concentration of CA19-9

A 52 year old woman had autoimmune hepatitis and an increased concentration of serum carbohydrate antigen 19-9 (CA19-9). The origin of the raised CA19-9 was studied using immunohistochemistry. Liver biopsy section showed chronic active hepatitis with large numbers of proliferated bile ductules. Immunohistochemical analysis revealed that the proliferated bile ductule cells were positive for proliferating cell nuclear antigen (PCNA) and for CA19-9. It is speculated that the raised serum CA19-9 concentration was derived from proliferated bile ductule cells and these cells, which are positive for PCNA, may be able to produce high concentrations of CA19-9.

Calcium-dependent Ret activation by GDNF and neurturin

Glial cell line-derived neurotrophic factor (GDNF) and neurturin (NTN) define a new family of neurotrophic factors that play crucial roles in survival and differentiation of various neurons. Recent studies demonstrated that GDNF and NTN use a multicomponent receptor system in which glycosyl-phosphatidylinositol (GPI)-linked cell surface proteins and Ret receptor tyrosine kinase function as the ligand-binding and signalling components, respectively. In the present study, we investigated the role of Ca2+ ions for biochemical and biological activities of Ret because Ret has a unique structure of the extracellular domain with the cadherin-like motif. The results demonstrated that Ca2+ ions might be required for the complex formation of Ret and GDNF or NTN that induces Ret oligomerization and autophosphorylation. Full morphological differentiation of neuroblastoma cells by these neurotrophic factors was also Ca2+-dependent. These findings thus suggested that, in addition to GPI-linked cell surface proteins, Ca2+ ions are components of the signal transducing complex formed by Ret and GDNF protein family.

Bidirectional signaling between sarcoglycans and the integrin adhesion system in cultured L6 myocytes

The rat L6 skeletal muscle cell line was used to study expression of the dystrophin-containing glycoprotein complex and its interaction with the integrin system involved in the cell-matrix adhesion reaction. A complex of dystrophin and its associated proteins was fully expressed in L6 myotubes, from which anti-dystrophin or anti-alpha-sarcoglycan co-precipitated integrin alpha 5 beta 1 and other focal adhesion-associated proteins vinculin, talin, paxillin, and focal adhesion kinase. Immunostaining and confocal microscopy revealed that dystrophin, alpha-sarcoglycan, integrin alpha 5 beta 1, and vinculin exhibited overlapping distribution in the sarcolemma, especially at focal adhesion-like, spotty structures. Adhesion of cells to fibronectin- or collagen type I-coated dishes resulted in induction of tyrosine phosphorylation of alpha- and gamma-sarcoglycans but not beta-sarcoglycan. The same proteins were also tyrosine-phosphorylated when L6 cells in suspension were exposed to Arg-Gly-Asp-Ser peptide. All of these tyrosine phosphorylations were inhibited by herbimycin A. On the other hand, treatment of L6 myotubes with alpha- and gamma-sarcoglycan antisense oligodeoxynucleotides resulted in complete disappearance of alpha- and gamma-sarcoglycans and in significant reduction of levels of the associated focal adhesion proteins, which caused about 50% reduction of cell adhesion. These results indicate the existence of bidirectional communication between the dystrophin-containing complex and the integrin adhesion system in cultured L6 myocytes.

[A case of total arch replacement for redissected impending rupture of early thrombosed aortic dissection without intimal tear detectable at operation]

A 51-year-old suddenly developed severe chest and back pains. The diagnosis was acute aortic dissection of Stanford type A, but the dissecting space was not observed by enhanced CT scan. Medical treatment was started as early thrombosed aortic dissection. The blood pressure was sufficiently controlled, and the symptom was gradually improved. On the 8th hospital day, a severe chest pain appeared again, Enhanced CT scan showed an enlarged dissecting space, pericardial and pleural effusion. These findings were considered a redissected impending rupture, so the emergency operation was performed. Fresh clots were observed in the dissecting space of ascending aorta, but the intimal tear was not found in any portion of the examined aorta. Therefore total arch replacement was needed to resect the wall which may be responsible for the dissection and to reduce the residual dissecting space. The patient recovered without complications. Postoperative CT scan revealed no residual false lumen in the distal descending aorta.

[Talc pulmonary granulomatosis caused by intravenous administration of methylphenidate]

A 57-year-old man was admitted with fever and a dry cough in 1985. He had used methylphenidate intravenously for 3 years. A chest X-ray film on admission showed diffuse micronodular shadows and massive lesions in the lower lung fields bilaterally. Pulmonary granulomatosis was diagnosed histologically, but the etiology remained unclear. In 1993, the patient was readmitted because of symptom exacerbation. The micronodular shadows had extended and the bilateral, massive lesions had enlarged. Transbronchial lung biopsy revealed granulomas with crystallized foreign bodies. Electron microscopy confirmed that the foreign bodies consisted of magnesium and silicon, suggesting talc. Talc granulomatosis caused by intravenous administration of methylphenidate was subsequently diagnosed. The symptoms improved with conservative treatment, and no signs of reexacerbation have appeared.

[Current status and problems of home parenteral nutrition for terminal cancer patients from the viewpoint of indication]

Since June 1993, we have been performing home parenteral nutrition (HPN) for end-stage cancer patients. We studied how many patients could be treated with HPN, why they were not able to be treated with HPN in the terminal stage cancer patients, 158 cases, who admitted and died in our ward from June 1993 to April 1997. Eighty-six patients (54.4%) were considered to not be indicated for HPN, due to general weakness (28 cases), dyspnea (17 cases), need for medical care other than HPN (34 cases), and inability to understand this treatment (1 case). Fifty-six patients (35.4%) were considered to have been able to be treated with HPN and could have had returned home. Fifteen patients (26.8%) were given HPN. Four cases wanted to stay in the hospital after they knew the truth and the prognosis of their disease. Another four patients became weak while preparing for HPN and could not go home. Eighty percent of patients could not to be treated with HPN because of the factors of their family. Eight patients had no family to cared for them. Twelve patients were refused to the truth of their disease. The families of 13 cases refused to accept and care for them in their home. We may conclude that co-operation among patients, their family and the medical staff is the most important factor in providing HPN for end-stage cancer patients.

[Sequence variability in Borna disease virus ORF II from human beings]

40 clones from five psychiatric patients and three healthy blood donors in whom Borna disease virus (BDV) ORF II fragments in PBMC were previously proved by nested RT-PCR were sequenced and compared with BDV/MDCK. There were eleven point mutations in all clones compared with reported HE80-1, but no difference between human and BDV/MDCK clones. We found specific sequence variability at nt 1701 in ten clones from two psychiatric disorder patients (T-->C) and at nt 1696 in fifteen clones from three healthy blood donors (A-->T). This result strongly suggests there are some special gene divergence in BDV derived from human beings.

Left midcardiac border of frontal chest radiographs of patients with annulo-aortic ectasia

The utility of the frontal chest radiograph for the diagnosis of annulo-aortic ectasia (AAE) was evaluated in 12 patients with Marfan's syndrome and five patients with incomplete stigmata (forme fruste). Prominence of the left midcardiac border was seen in 11 patients: the upper midsegment in one, the lower midsegment in two, and the whole midsegment in eight patients. Either a linear or an arcuate contour was seen. The contours of the prominent left midcardiac border in three patients who had moderate to marked aortic regurgitation and a cardiothoracic ratio (CTR) over 59% were nonspecific. In the remaining eight patients (47%), the contour was considered to be characteristic of AAE, as suggested by the displacement of either all or part of the right ventricular outflow tract, main pulmonary artery and left atrial appendage. Six patients showed only left midcardiac border prominence. The contour of the left midcardiac border on the conventional frontal chest radiograph is characteristic and of paramount importance for the diagnosis of AAE in Marfan' s syndrome or its forme fruste, particularly in patients whose CTRs are within the normal range.

Characterization of Ret-Shc-Grb2 complex induced by GDNF, MEN 2A, and MEN 2B mutations

We analyzed the intracellular signalling pathway through Ret activated by glial-cell-line-derived neurotrophic factor (GDNF), multiple endocrine neoplasia (MEN) 2A and 2B mutations. The results showed that all of them induce a signal transducing complex consisting of Ret, Shc, and Grb2 proteins. In addition, GDNF clearly activated a Ras-MAPK pathway in human neuroblastoma cells. Rat is expressed mainly as two isoforms that differ in the carboxy-terminal sequence: a long isoform (1114 amino acids) and a short isoform (1072 amino acids). The long isoform contains the consensus sequence for binding of the Shc PTB domain but not of its SH2 domain, whereas the short isoform has the consensus sequences for binding of both domains. In vitro binding assay revealed that the long isoform of the MEN2A-Ret protein and both isoforms of the MEN2B-Ret protein bound preferentially to the Shc PTB domain. On the other hand, the short isoform of MEN2A-Ret bound to the PTB and SH2 domains. In neuroblastoma cells expressing both isoforms of Ret, its activation by GDNF also resulted in the binding of both domains. GDNF and MEN 2A mutations activate Ret by inducing its dimerization, whereas the MEN 2B mutation increases Ret catalytic activity without dimerization. Our results thus suggest that Ret dimerization might be required for binding of the Shc SH2 domain to the short isoform.

Biological properties of Ret with cysteine mutations correlate with multiple endocrine neoplasia type 2A, familial medullary thyroid carcinoma, and Hirschsprung's disease phenotype

We investigated the transforming activity of the ret proto-oncogene with a mutation in cysteine 609, 611, 618, 620, 630, or 634 detected in patients with multiple endocrine neoplasia type 2A (MEN 2A), familial medullary thyroid carcinoma (FMTC), or Hirschsprung's disease. Of these cysteine mutations, codon 634 mutations are known to be correlated with the development of MEN 2A, whereas codon 609, 618, or 620 mutations were detected in two-thirds of FMTCs and in several cases of Hirschsprung's disease. Analysis of a total of 18 mutant genes revealed that codon 634 mutations have the highest transforming activity. The activity of ret with a codon 609, 611, 618, or 620 mutation and with a codon 630 mutation was approximately 3- to 5-fold and 2-fold lower than that of ret with a codon 634 mutation, respectively. In addition, different amino acid substitutions for the same cysteine displayed comparable transforming activity. The expression of the cell surface form of Ret with codon 609, 611, 618, or 620 mutation was very low compared with that of Ret with codon 634 mutation, indicating that the former four mutations might impair transport of Ret to the plasma membrane, as observed for several Hirschsprung mutations affecting the Ret extracellular domain. These results thus suggest that mutations in cysteine 609, 611, 618, or 620 may have the potential to develop Hirschsprung's disease in addition to MEN 2A and FMTC.

Expression of matrix metalloproteinase (gelatinase) in T1 adenocarcinoma of the lung

The expression of matrix metalloproteinase-2 (MMP-2; 72 kDa type IV collagenase/gelatinase A) and MMP-9 (92 kDa type IV collagenase/gelatinase B) was immunohistochemically investigated in 79 T1 adenocarcinomas of the lung using non-commercial polyclonal anti-MMP-2 and -9 antibodies. Thirty-two (41%) and 22 (28%) among the 79 cases were positive in the tumor cells for MMP-2 and -9, respectively. The incidences of MMP-2 and -9 immunoreactivities were higher (64 and 45%, respectively) in poorly differentiated tumors than in well differentiated tumors (36 and 25%, respectively), and lower in bronchioloalveolar carcinoma (22 and 10%, respectively) compared with other subtypes of adenocarcinoma. The prognosis for patients with MMP-2 and/or -9 positive immunoreactivities was significantly poorer than for those with a MMP-negative tumor (P < 0.05). The degree of collagenization was divided into four grades, and tumors with a small to abundant amount of collagen (grade 2 and grade 3 fibrosis) had a higher incidence of immunoreactivity to both types of MMP. It is estimated that these expressions might be responsible for tumor invasion, metastasis, and for grade 2 and grade 3 fibrosis in T1 adenocarcinoma of the lung.

[CABG performed for LMT orifice stenosis 15 years after AVR in a case of aortitis syndrome]

The case is a 54-year-old female at age 39 years, she underwent aortic valve replacement (AVR) for aortic valve regurgitation (AR) due to aortitis syndrome at a certain hospital. At the 15th year after AVR she was diagnosed with unstable angina due to LMT orifice stenosis and underwent CABG at this hospital. A distal side of anastomosis was performed on the LAD branch seg 6, an artificial vascular patch was placed for the proximal side of anastomosis to prevent inflammation of the aortic wall from spreading to the proximal side of anastomosis. On the postoperative cardiac catheter examination, the graft was found to be patent well. In the case of CABG complicated with aortitis syndrome, stenosis and obstruction of the proximal side of anastomosis long time after surgery pose a problem. However, the method so as to perform a proximal anastomosis by placing an artificial vascular patch on the aortic wall is considered to be one of the useful means which can avoid such a problem.

Macrophage cathepsin L, a factor in the erosion of subchondral bone in rheumatoid arthritis

OBJECTIVE

To test the hypothesis that the proteinase cathepsin L is involved in the subchondral bone lesions found in chronic rheumatoid arthritis (RA).

METHODS

The medial tibial plateaus from 4 control cases and 30 patients diagnosed as having end-stage RA were examined immunochemically for cathepsin L.

RESULTS

RA lesions include large groups of mononuclear cells, many of which are rich in cathepsin L. Since these mononuclear cells contained the CD68 glycoprotein and, in the electron microscope, displayed an irregular cell surface, cytoplasmic vacuoles, lysosomes, and phagosomes, they were identified as belonging to the macrophage family. The lesions were classified into 2 main patterns, both displaying these cathepsin L-rich cells, which, in at least 1 of the 2, were closely associated with bone degradation.

CONCLUSION

The cathepsin L-rich macrophages are sufficiently numerous to be considered a major factor in producing the erosion of subchondral bone found in chronic RA lesions.

mRNA expression and cDNA sequences of beta- and gamma-sarcoglycans are normal in cardiomyopathic hamster heart

In BIO14.6 cardiomyopathic hamster heart, the dystrophin-glycoprotein complex is disrupted and sarcoglycans are greatly reduced in abundance. We examined whether the gene expression of beta- and gamma-sarcoglycans is indeed defective in this hamster. We found that mRNA expression for these proteins and the cDNA sequences of their coding regions are identical in both normal and myopathic hamster cardiomyocytes. The results strongly suggest that defect in a currently unknown sarcoglycan-associated protein(s) is responsible for the deficiency of the sarcoglycan complex that leads to muscle cell necrosis in the myopathic hamster.