Structural elements of an orphan nuclear receptor-DNA complex

The nuclear hormone receptors form the largest known family of transcription factors. The current notion of receptor DNA discrimination, based solely on one major type of hexameric half-site and a highly conserved 66-residue core DNA-binding domain (DBD), does not adequately describe how more than 150 nonsteroid receptors differentiate among response elements. Here, we describe the 2.3 A crystal structure of the DNA-binding region of the orphan receptor RevErb arranged as a tandem homodimer on its optimal response element. The structure reveals the presence of a second major protein-DNA interface adjacent to the classical one involving the half-sites. A sequence comparison of orphan receptors suggests that unique minor-groove interactions involving the receptor hinge regions impart the necessary DNA and dimerization specificity.

Topographical distribution of [125I]-glial cell line-derived neurotrophic factor in unlesioned and MPTP-lesioned rhesus monkey brain following a bolus intraventricular injection

The present study determined the topographical distribution profile for [125I]-glial cell line-derived neurotrophic factor in unlesioned and MPTP-lesioned (unilateral intracarotid injection) rhesus monkeys following an intraventricular injection. Autoradiographic analysis showed that following a bolus intraventricular injection, there was widespread distribution of [125I]-glial cell line-derived neurotrophic factor throughout the ventricular system (walls of lateral, third, and fourth ventricles and aqueduct), with some accumulation at the lateral ventricle injection site, possibly associated with the ependymal cell layer. In both unlesioned and MPTP-lesioned monkeys, there was labelling of the cerebral cortex, substantia nigra/ventral tegmental area and sequestration of [125I]-glial cell line-derived neurotrophic factor adjacent to the hippocampal formation, globus pallidus, ventral to and in the substantia nigra. However, [125I]-glial cell line-derived neurotrophic factor did not appear to diffuse readily or accumulate in the caudate-putamen even though there was some penetration away from the ventricular walls. Throughout the brain, there was also substantial non-parenchymal labelling of [125I]-glial cell line-derived neurotrophic factor, possibly associated with extracellular matrix components, meninges and vasculature due to the heparin binding properties of glial cell line-derived neurotrophic factor. In addition to the extensive loss of tyrosine hydroxylase immunoreactivity within the substantia nigra, there was also decreased accumulation of [125I]-glial cell line-derived neurotrophic factor and reduced glial cell line-derived neurotrophic factor immunoreactivity ipsilateral to the lesion. Microscopic analysis showed that glial cell line-derived neurotrophic factor immunoreactivity was associated with upper cortical layers including a high density of immunoreactivity at the surface of the cortex (meningeal, pial layer, vasculature) and around the ventricular walls (with some cellular labelling and labelling of vasculature). Moderate staining was observed in nigral cells contralateral to the MPTP-lesion, whereas only minimal levels of that glial cell line-derived neurotrophic factor immunoreactivity were detected ipsilateral to the lesion. This study shows that intraventricularly injected glial cell line-derived neurotrophic factor accumulates not only around the ventricular walls, but also in specific brain regions in which sub-populations of cells are more readily accessible than others. The presence of cells labelled with [125I] and immunopositive for glial cell line-derived neurotrophic factor in the substantia nigra indicates that these cells are a target for the trophic factor following intraventricular administration. Thus, the behavioral improvement observed in MPTP-lesioned monkeys following an intraventricular injection of glial cell line-derived neurotrophic factor is likely the result of activation of nigral cells.

Cloning, sequencing, and expression of the Bombyx mori receptor for Bacillus thuringiensis insecticidal CryIA(a) toxin

Bacillus thuringiensis strains produce insect-specific Bt toxins. Bt CryIA(a) toxin binds to a 175-kDa glycoprotein (BtR175) on the microvillus membranes of columnar cells in the Bombyx mori midgut and causes lysis of the cells. BtR175 was purified, and its cDNA was cloned. The cDNA encodes a newly identified 193.3-kDa preproprotein form of BtR175 that includes nine extracellular cadherin repeats, a 23.5-kDa membrane-proximal domain, a membrane-spanning region, and a 13.6-kDa cytoplasmic domain. Spodoptera frugiperda cells transfected with a recombinant baculovirus DNA carrying the cDNA produced a 175-kDa protein that reacted with anti-BtR antibodies and the Bt CryIA(a) toxin.

Activation of the beta-catenin gene by interstitial deletions involving exon 3 in primary colorectal carcinomas without adenomatous polyposis coli mutations

Among 222 primary colorectal cancers we examined, 58 showed no detectable APC mutations by the protein truncation test. We screened those 58 tumors for somatic mutations in the beta-catenin gene. Although amino acid substitutions in serine or threonine residues in exon 3 had been reported, we found no such mutations; however, in seven tumors, we detected somatic interstitial deletions of 234-760 bp, each of which included all or part of exon 3. Short nucleotide sequences at both ends of each deletion were either identical or complementary, indicating that repeated or inversely repeated sequences were involved in the somatic rearrangements. Reverse transcription-PCR experiments using RNAs isolated from three of these seven tumors detected transcripts that lacked exon 3, in addition to the normal transcript. In one of these cases, we confirmed accumulation of aberrant beta-catenin protein in cytoplasm and nuclei of cancer cells by Western and immunohistochemical analyses. This result suggested that, in the absence of a peptide encoded by exon 3, beta-catenin is stabilized and has a dominant oncogenic effect on colorectal tumorigenesis.

Comparison of the functional properties of three different truncated thyroid hormone receptors identified in subjects with resistance to thyroid hormone

The tau4 domain in the extreme carboxyl (C) terminal region of thyroid hormone receptor (TR) is important to transactivation. We identified three truncated TRbeta1s with 11 (F451X), 13 (E449X) and 16 (C446X) amino acid deletions within this domain in subjects with resistance to thyroid hormone (RTH). F451X and C446X were found in a 6-year-old Japanese girl and a 31-year-old American male, respectively, who had both severe mental retardation. E449X was identified in a 16-year-old Japanese boy with no remarkable clinical symptoms except for goiter. Transient expression study revealed that all three mutants had negligible T3 binding and transcriptional activities. Each mutant TRbeta1 exhibited not only very strong dominant negative activity against wild TRbeta1, but also marked silencing activity. Interestingly, the dominant negative activity and silencing activity were significantly stronger in F451X than in E449X and C446X (P < 0.05). Gel-shift experiments revealed no apparent differences in homodimer formations of wild-type or mutant TRbeta1 proteins and in heterodimer formations with retinoid X receptor (RXR). These observations indicate that the tau4 domain affects diverse TR functions, and that the region between 11 and 13 C-terminal amino acids influences ligand-independent TR functions, including dominant negative and silencing activities. The central nervous system involvement is not necessarily determined by the dominant negative potency of the mutant TRbeta1 and other environmental or genetic factors may influence the RTH manifestations.

Early viral complications following CD34-selected autologous peripheral blood stem cell transplantation for non-Hodgkin's lymphoma

A patient with non-Hodgkin's lymphoma who received a CD34-selected autologous peripheral blood stem cell transplant (PBSCT) developed cytomegalovirus retinitis, adenovirus-associated haemorrhagic cystitis (HC) and fatal herpes simplex virus pneumonia. Depletion of mature T cells from the graft and a persistent decrease in CD4+ lymphocytes following PBSCT may have predisposed this patient to such viral infections. Infusion of cryopreserved autologous PBSC (containing mature T cells) was effective for adenovirus-associated HC. Immunosuppression and resultant viral infections may affect patients receiving CD34-selected autologous transplantation.

[A case of poorly differentiated adenocarcinoma of prostate with neuroendocrine differentiation]

A 59-year-old man was diagnosed with clinical stage D1 poorly differentiated prostatic adenocarcinoma (PAC). The patient was treated with total androgen blockade therapy. The tumor recurred 18 months later. Digital rectal examination revealed a large, stony-hard prostate. The serum PSA level was within normal limits. Pathological examination of the prostate revealed conventional adenocarcinoma with large numbers of neuroendocrine (NE) cells. The patient died 3 months after the diagnosis of PAC with NE differentiation, 22 months after the initial diagnosis of prostate cancer.

Localization of the gene responsible for Peutz-Jeghers syndrome within a 6-cM region of chromosome 19p13.3

Patients with Peutz-Jeghers syndrome (PJS), an autosomal dominant disease characterized by hamartomatous polyposis of the gastrointestinal tract, are thought to be predisposed to malignancies of the digestive tract, genital tract, and other organs. Using microsatellite markers on chromosome 19p, we have closely defined the region containing the gene responsible for this disorder through linkage analysis in seven affected families. The lack of obligate recombinants at two of these loci, D19S883 and D19S878, with maximum LOD scores of 2.88 and 3.75, confirmed the localization of the PJS locus to chromosome 19. Furthermore, haplotype analysis placed the PJS locus within a 6-cM telomeric region of chromosome 19p, between D19S886 and D19S565.

Infrequent mutations in the PTEN/MMAC1 gene among primary breast cancers

Recently PTEN/MMAC1, a candidate tumor suppressor gene, was isolated from chromosome 10q23-24 and somatic mutations of this gene were detected in several malignancies including brain, prostate, and breast tumors. To investigate further the potential role of this gene in mammary carcinogenesis, we examined 69 primary breast cancers for mutations in PTEN/MMAC1 by means of polymerase chain reaction single-strand conformation polymorphism and sequencing analysis. We detected only one somatic missense mutation, a change from T to C at codon 59 (TCA to CCA) resulting in substitution of Pro for Ser in the predicted protein. This site is located outside of phosphatase or phosphate-acceptor motifs, but this codon encodes a residue that is conserved in homologous proteins, tensin and auxilin and is likely to be crucial for normal function of PTEN/MMAC1. Among the 69 tumors examined, three low-frequency polymorphisms were found as well, one in the non-coding region of exon 1 and one each in introns 2 and 7. Our results suggested that mutation of the PTEN/MMAC1 gene is not a major factor in the development of most primary breast cancers.

[Effects of milrinone in patients undergoing cardiac surgery]

We investigated effects of milrinone in twenty consecutive patients (6 adults, 1 child, and 3 early infants) during cardiac surgery requiring cardiopulmonary bypass (CPB). The operations were: CABG 5, CABG+mitral valve repair 2, MVR 2, redo-MVR 4, aortic surgery 3 (total arch replacement 2), VSD+pulmonary hypertension 2 (infants), Tetralogy of Fallot 1, and PDA aneurysm 1 (infant). Ten minutes after release of aortic cross-clamp, all patients received milrinone by loading dose (50 micrograms/kg, bolus), followed by a continuous infusion of 0.5 or 0.75 microgram/kg/min. All of patients weaned from CPB with milrinone and low-dose of dopamine. The 75% of patients did not require any other drugs except for milrinone during post operative ICU stay. At the same time, we evaluated the effect of milrinone on platelet number in the patients before and after CPB. Milrinone administration did not cause significant changes in platelet number after CPB. No adverse effects attributable to this drug were found. Milrinone appears to be effective and safe in patients undergoing cardiac surgery of all kinds.

Isolation, mapping and mutation analysis of a human cDNA homologous to the doc-1 gene of the Chinese hamster, a candidate tumor suppressor for oral cancer

We have isolated a human cDNA encoding a 115-amino-acid polypeptide that revealed 97% identity to a candidate tumor suppressor gene for oral cancer in Mesocricetus auratus (deleted in oral cancer-1; doc-1). It also showed a high degree of homology to a gene induced by TNF-alpha in Mus musculus. To investigate its possible role in esophageal carcinogenesis, we examined genetic alterations and expression levels of the gene in 13 esophageal carcinoma cell lines and 10 primary esophageal carcinomas. No mutation nor reduction of expression was observed in any of the 23 cancer materials examined. These results imply that the human doc-1 homologue is unlikely to play a significant role in esophageal carcinogenesis, although its role in the TNF-alpha signaling pathway remains unclear. We mapped DOC1 to chromosome band 12q24.31 by fluorescence in situ hybridization.

A mutant thyroid hormone receptor beta 1 identified in a patient with resistance to thyroid hormone inhibits the activities of not only the wild-type TRs, but also other nuclear receptors

Although mutations of human thyroid hormone receptor beta (hTR beta) have been associated with resistance to thyroid hormone (RTH), the molecular basis by which the mutant TRs cause the various clinical symptoms is unknown. We show here that a mutant TR beta [corrected] identified in a patient with RTH inhibited the transcriptional activities of, not only the wild-type TR beta, but also other nuclear receptors including retinoid X receptor alpha (RXR alpha), vitamin D3 receptor (VDR) and retinoic acid receptor (RAR alpha). We provide evidence that these inhibitions by the mutant TR beta [corrected] occur by different mechanisms. Namely, the mutant TR beta interferes with VDR and RAR alpha by competition for binding to the corresponding response elements, but the pathway through RXR alpha is mainly inhibited by squelching of RXR alpha in solution. These findings suggest that in patients with RTH, not only the T3 responsive genes but also other responsive genes are inhibited by the mutant TRs, which might explain the variety of clinical symptoms in RTH.

Dimerization properties of mutant thyroid hormone beta-receptors with auxiliary proteins

Hormonal responsiveness in peripheral tissues is variable in patients with resistance to thyroid hormone (RTH). One cause of this may be differential interaction of RTH mutants of thyroid hormone receptor beta (TR beta) with TR auxiliary proteins (TRAPs). We used gel shift mobility assays to examine the interaction of wild-type and mutant TR beta s with retinoid X receptors (RXRs) and endogenous TRAPs. Some mutants showed reduced homodimerization but retained heterodimerization with recombinant RXRs. Wild-type TR beta formed heterodimeric complexes with multiple TRAPs in nuclear extracts of rat tissues, but RTH mutants showed variably altered heterodimerization with each TRAP. With liver nuclear extract, all mutants with impaired homodimerization also showed impaired TR beta-TRAP heterodimerization. Thus heterodimerizations with RXRs and TRAPs are differently affected by RTH mutations. Our results suggest that multiple TRAPs are expressed in tissue-specific patterns. The variability of TR beta heterodimerization with TRAPs may account, in part, for the variable tissue responsiveness in RTH.

[Congenital mid-ureteral stricture: report of a case]

A rare case of congenital mid-ureteral stricture is reported. A 17-year-old woman was admitted with sudden onset of right flank pain. Intravenous urography demonstrated bilateral small renal calculi, left hydronephrosis and a stricture of the left ureter at the level of the pelvic brim. The diagnosis was determined as congenital mid-ureteral stricture because the ureter tapered smoothly from 25 mm to 5 mm in diameter at the stenotic site. She was successfully treated by partial ureterectomy with end-to-end anastomosis. Histopathologically, no dysplasia of muscular layer was recognized.

Dose response to intraventricular glial cell line-derived neurotrophic factor administration in parkinsonian monkeys

A double-blinded study was conducted to evaluate the dose response of hemiparkinsonian rhesus monkeys to intracerebroventricular (ICV) injections of recombinant methionine human glial cell line-derived neurotrophic factor (GDNF). Thirty rhesus monkeys with stable hemiparkinsonian features were divided into six treatment groups (vehicle, 10, 30, 100, 300 and 1000 microg GDNF; n = 5/group). Each animal received 4 ICV administrations spaced at four week intervals. In addition, the animals were followed for 4 mo after the last injection. Standardized video taped behavioral tests were used to rate parkinsonian features using a nonhuman primate rating scale and assess side effects from treatment. Significant behavioral improvements were measured in animals receiving 100 to 1000 microg GDNF. One month after the last GDNF administration, parkinsonian features in animals receiving 100 and 1000 microg GDNF began to return to baseline levels. However, 300 microg GDNF recipients continued to display behavioral improvements. Parkinsonian features significantly improved were: bradykinesia, rigidity, posture and balance. The most common side effect was a transient weight loss after GDNF administration. Only one other side effect was observed, one animal receiving 1000 microg GDNF displayed dyskinetic movements. The results provide additional information for evaluating the possible clinical application of GDNF for treating Parkinson's disease.

Glial cell line-derived neurotrophic factor-levodopa interactions and reduction of side effects in parkinsonian monkeys

Glial cell line-derived neurotrophic factor (GDNF) stimulates the nigrostriatal dopaminergic pathway and improves motor functions in animal models of parkinsonism. Sinemet is currently the most widely used drug for treating Parkinson's disease. The present study has evaluated GDNF-Sinemet interactions in parkinsonian rhesus monkeys. Both GDNF and Sinemet, when given alone, significantly improved total parkinsonian scores. The response to Sinemet did not change after intracerebroventricular vehicle injections. In contrast, there was a functional interaction between GDNF and levodopa. When comparing the levodopa dose response before and after GDNF treatment, significant behavioral improvements were seen after trophic factor administration at every levodopa dose level except 500 mg. Adverse responses to Sinemet treatment alone in parkinsonian animals included vomiting, dykinesias, dystonias, and stereotypic movements. Combined GDNF-Sinemet treatment significantly reduced the occurrence of these levodopa-induced side effects, with a >90% decrease in adverse responses seen at the mid-Sinemet (250 mg levodopa-25 mg carbidopa) dose level. The only side effect from GDNF treatment was a transitory weight loss. Thus, combined GDNF-Sinemet treatment could be of therapeutic value in treating parkinsonism, by producing a greater functional response and by mitigating adverse responses to Sinemet treatment.

[Metastatic renal tumor originating from esophageal cancer: report of 2 cases]

We report 2 cases of esophageal cancer metastatic to the kidney. The first case was in a 57-year-old man who complained of severe right flank pain. He had underwent an operation for esophageal cancer 2 months previously. A computerized tomography (CT) scan revealed a wedge-shaped, low-density mass in the right kidney. Right nephrectomy revealed squamous cell carcinoma. He has remained free of recurrence 3 months postoperatively. The second case was in a 57-year-old man with esophageal cancer treated by radiation therapy. Severe right flank pain and gross hematuria appeared after 1 year. A CT scan showed a wedge-shaped, low-density tumor in the right kidney accompanied with a tumor thrombus in the inferior vena cava. Right nephrectomy as well as resection of the thrombus were performed. Pathological diagnosis was squamous cell carcinoma. He died of cancer 2 months postoperatively.

[A case of CEA and CA19-9 producing recurrent transitional cell carcinoma in an Indiana pouch after total cystectomy]

A 73-year-old female with transitional cell carcinoma (TCC) of the bladder underwent total cystectomy and Indiana pouch replacement in April, 1992. Histological examination revealed grade 3 TCC. In February 1995, she complained of gross hematuria. Intravenous pyelography (IVP) revealed a right non-functional kidney and filling defect in the Indiana pouch. We suspected colon cancer in the Indiana pouch because the levels of serum carcino-embryonic antigen (CEA) and CA19-9 were elevated. Endoscopic biopsy of intrapouch tumor was done. Pathological examination revealed grade 2 TCC. In July 1995, right nephroureterectomy with resection of Indiana pouch was performed and the surgical specimen revealed renal pelvic and ureteral cancer, grade 2 TCC. The levels of serum CEA and CA19-9 returned to the normal range 21 days after the operation. CEA and CA19-9 histochemical stain of renal pelvic and ureteral cancer were positive. Also CEA-, CA19-9-positive cells were detected in the specimens of the bladder tumor from the total cystectomy performed in 1992. This rare case is discussed and the literature is reviewed.

High-dose intravenous steroid pulse therapy in thyroid-associated ophthalmopathy

To evaluate the efficacy of high-dose intravenous steroid pulse followed by oral steroids in the treatment of thyroid-associated ophthalmopathy, we performed clinical assessment and measurement of retroorbital muscle enlargement in 27 patients before and after the therapy, and followed them up longitudinally. The mean duration of follow up is (mean +/- SD) 29.8 +/- 23.8 months (range 4-92). Diplopia disappeared in 10 patients and ameliorated in 11 patients. The degree of proptosis decreased in 15 patients and the fall in visual acuity improved in a third of the patients. The total ophthalmopathy index (OI) decreased from 7.0 +/- 1.9 to 3.0 +/- 1.5. The extraocular muscle enlargement (EME), expressed as the maximal ratio of extraocular muscle thickness to the diameter of the optic nerve, decreased from 2.33 +/- 0.56 to 1.27 +/- 0.26. No major side effects were found in any patient. The improvement in the eye disease was found immediately after the pulse therapy, prior to the start of the following therapy by oral steroids and/or orbital irradiation. Both of OI and EME decreased with time after the therapy and did not get worse after withdrawing oral steroids. The efficacy of the therapy evaluated by degrees of improvement in OI and in EME was significantly greater in females than in males. Although there was a significant positive correlation between initial OI and EME values and initial TBII and TSAb activities, a significant correlation was seen only between the degrees of improvement in EME and changes in TBII activity due to the therapy. The duration of eye disease, thyroid status, treatment with anti-thyroid drug, smoking and experience of previous treatment did not affect the efficacy of the present therapy. We conclude that high-dose intravenous steroid pulse therapy is effective and safe for thyroid-associated ophthalmopathy.

Mutations of the transforming growth factor beta type II receptor gene and microsatellite instability in gastric cancer

Forty-three sporadic gastric cancers were analyzed with regard to whether mutations of simple repeated sequences in the transforming growth factor beta type II receptor (TbetaR-II) gene are associated with microsatellite instability (MSI) and gastric carcinogenesis. In 12 of the 43 cancers (28%), MSI was observed at least at 1 of the 2 microsatellite loci. Frameshift mutations of the TbetaR-II gene, all of which were 1 base deletion of 10 adenine repeats, were detected in 3 of 6 cancers, with MSI at 2 loci. However, mutations were not detected in 6 cancers, with MSI only at 1 locus and 31 cancers without MSI. Moreover, microanalysis in these cases revealed that the mutant-type alleles of TbetaR-II were invariably common in different areas within the tumor, in contrast to the markedly variable alleles of microsatellite loci. Our results suggest that frameshift mutation of the TbetaR-II gene may be a critical event associated with MSI and may contribute to carcinogenesis of the stomach. One of the possible mechanisms of escape from growth control by TGFbeta during gastric carcinogenesis could involve frameshift mutations of the TbetaR-II gene caused by DNA replication errors.