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Biomedical subjects

D Trump

Publications and source records attributed to D Trump.

At least 37 records · Page 2Linked to original sources

Identification and characterization of the human homologue (RAI2) of a mouse retinoic acid-induced gene in Xp22.

We have identified a novel human gene during studies of a 1.3-Mb region of Xp22 between DXS418 and DXS999. A PAC contig spanning the region was constructed, sequenced, and analyzed by gene and exon prediction programs and by homology searches. Further investigation of predicted exons from PAC clone 389A20 led to the identification of a single-exon gene, designated RAI2 (retinoic acid-induced 2). RAI2 mapped 28 kb centromeric to marker DXS7996, between DXS7996 and DXS7997, and was transcribed from centromere to telomere. Northern blot analysis and reverse transcription-polymerase chain reaction analysis revealed expression of a 2.5-kb transcript in four fetal tissues (brain, lung, kidney, and heart) and eight adult tissues (heart, brain, placenta, lung, skeletal muscle, kidney, pancreas, and retina) but not in fetal or adult liver. The 530-amino-acid protein (57 kDa predicted mass) displays 94% homology with a mouse retinoic acid-induced gene product and contains a novel proline-rich (39%) domain of 68 amino acids. Retinoic acid is involved in vertebrate anteroposterior axis formation and cellular differentiation and has been shown to modulate gene expression controlling early embryonal development, suggesting a developmental role for RAI2. RAI2 remains a candidate gene for diseases mapping to the Xp22 region.

Amino Acid Sequence↗

Exclusion of RAI2 as the causative gene for Nance-Horan syndrome.

Nance-Horan syndrome (NHS) is an X-linked condition characterised by congenital cataracts, microphthalmia and/or microcornea, unusual dental morphology, dysmorphic facial features, and developmental delay in some cases. Recent linkage studies have mapped the NHS disease gene to a 3.5-cM interval on Xp22.2 between DXS1053 and DXS443. We previously identified a human homologue of a mouse retinoic-acid-induced gene (RAI2) within the NHS critical flanking interval and have tested the gene as a candidate for Nance-Horan syndrome in nine NHS-affected families. Direct sequencing of the RAI2 gene and predicted promoter region has revealed no mutations in the families screened; RAI2 is therefore unlikely to be associated with NHS.

Abnormalities, Multiple↗

Mutations of the XLRS1 gene cause abnormalities of photoreceptor as well as inner retinal responses of the ERG.

Intensity-series rod and cone ERGs were recorded in 19 patients with XLRS and 26 control eyes. All patients were examined by one ophthalmologist and diagnosed on the basis of fundus appearance and evidence of the disease in other males in the same family. Mutations in the XLRS1 gene have been identified in 15 of the patients. Dark-adapted ERGs were significantly different from controls for all test conditions and for both a-wave and b-wave responses. Abnormalities were detectable in all patients but there was considerable variation in the severity of abnormality. One third of the patients had the dark-adapted 'negative-wave' response typically associated with inner retinal disorder, but about one third showed only mild depression of the b-wave while the remainder had abnormally low a-waves in addition to depressed b-waves. Light-adapted responses were also affected and both a-wave and b-wave responses differed significantly from controls, but the 'negative-wave' response was not seen in any patient. The severity of the ERG abnormality did not correlate with the classification of fundus appearance or patient age suggesting that retinal function is relatively stable throughout life. The severity of ERG abnormalities did not correlate with the type of mutation and responses could differ between affected males within the same family. These results indicate considerable heterogeneity of ERG response without clinical, age or genetic correlate. The abnormal a-wave responses indicate that photoreceptor as well as inner retinal layer function may be affected in XLRS, at least in some patients.

Adult↗

Hydrocortisone with or without mitoxantrone in men with hormone-refractory prostate cancer: results of the cancer and leukemia group B 9182 study.

PURPOSE: Approximately 40,000 men die each year of hormone-refractory prostate cancer (HRPC). The results of treatment with chemotherapy have been disappointing to date, with no trials demonstrating a benefit with respect to survival duration. Corticosteroids and mitoxantrone each have been shown to be active agents in this disease. The purpose of this study was to demonstrate an advantage of mitoxantrone and hydrocortisone (M+H) over hydrocortisone alone with respect to survival duration. PATIENTS AND METHODS: Two hundred forty-two patients with HRPC were randomized to receive either M+H or hydrocortisone alone. Patients were monitored for survival, time to disease progression, time to treatment failure, response, and quality-of-life (QOL) parameters. RESULTS: Treatment in both arms was well tolerated. Although there was a delay in time to treatment failure and disease progression in favor of M+H over hydrocortisone alone, there was no difference in overall survival (12.3 months for M+H v 12.6 months for hydrocortisone alone). There was an indication that QOL was better with M+H, in particular with respect to pain control. CONCLUSION: M+H generated more frequent responses and a delay in both time to treatment failure and disease progression compared with hydrocortisone alone. In addition, there was a possible benefit of M+H with respect to pain control over hydrocortisone alone. No improvement in survival was observed. Although M+H could be viewed as a palliative option for patients with HRPC, new drugs and novel strategies are needed to improve survival for this disease.

Aged↗

Identification and characterization of a novel serine-threonine kinase gene from the Xp22 region.

Eukaryotic protein kinases are part of a large and expanding family of proteins. Through our transcriptional mapping effort in the Xp22 region, we have isolated and sequenced the full-length transcript of STK9, a novel cDNA highly homologous to serine-threonine kinases. A number of human genetic disorders have been mapped to the region where STK9 has been localized including Nance-Horan (NH) syndrome, oral-facial-digital syndrome type 1 (OFD1), and a novel locus for nonsyndromic sensorineural deafness (DFN6). To evaluate the possible involvement of STK9 in any of the above-mentioned disorders, a 2416-bp full-length cDNA was assembled. The entire genomic structure of the gene, which is composed of 20 coding exons, was determined. Northern analysis revealed a transcript larger than 9.5 kb in several tissues including brain, lung, and kidney. The mouse homologue (Stk9) was identified and mapped in the mouse in the region syntenic to human Xp. This location is compatible with the location of the Xcat mutant, which shows congenital cataracts very similar to those observed in NH patients. Sequence homologies, expression pattern, and mapping information in both human and mouse make STK9 a candidate gene for the above-mentioned disorders.

Amino Acid Sequence↗

Characterization of SCML1, a new gene in Xp22, with homology to developmental polycomb genes.

Using exon trapping, we have identified a new human gene in Xp22 encoding a 3-kb mRNA. Expression of this RNA is detectable in a range of tissues but is most pronounced in skeletal muscle and heart. The gene, designated "sex comb on midleg-like-1" (SCML1), maps 14 kb centromeric of marker DXS418, between DXS418 and DXS7994, and is transcribed from telomere to centromere. SCML1 spans 18 kb of genomic DNA, consists of six exons, and has a 624-bp open reading frame. The predicted 27-kDa SCML1 protein contains two domains that each have a high homology to two Drosophila transcriptional repressors of the polycomb group (PcG) genes and their homologues in mouse and human. PcG genes are known to be involved in the regulation of homeotic genes, and the mammalian homologues of the PcG genes repress the expression of Hox genes. SCML1 appears to be a new human member of this gene group and may play an important role in the control of embryonal development.

Amino Acid Sequence↗

5-Fluorouracil and leucovorin therapy in patients with hormone refractory prostate cancer: an Eastern Cooperative Oncology Group phase II study (E1889).

This report is a multi-institutional phase II study designed to obtain the response rate, survival, and toxicity profile for patients having hormone-refractory prostate cancer. Patients who had bidimensionally measurable prostate carcinoma in first or second remission after previous hormonal therapy but no history of chemotherapy were eligible. Patients were treated with leucovorin, 20 mg/m2 intravenously, followed by 5-fluorouracil (5-FU), 425 mg/m2 intravenously daily for 5 days, with cycles repeated every 28 days. Of 38 eligible patients, 3 (7.9%) had partial responses to therapy and 20 (52.6%) had stable disease. Median survival was 11.6 months for all 38 patients and median time to progression was 4.4 months. Most of the serious side effects were gastrointestinal or hematologic and overall, 23 of 38 patients (60.5%) experienced at least one grade 3 or 4 treatment-related toxicity of any type, as measured by the National Cancer Institute common toxicity criteria. Five patients (13.2%) withdrew from the study because of adverse reactions from chemotherapy. We conclude that treatment of hormone-refractory prostate cancer patients with 5-FU and leucovorin chemotherapy produced few responses at the cost of significant side effects. Further investigation of this combination is not warranted in this setting.

Adenocarcinoma↗

Localisation of X linked recessive idiopathic hypoparathyroidism to a 1.5 Mb region on Xq26-q27.

X linked recessive idiopathic hypoparathyroidism (HPT) has been observed in two kindreds from Missouri, USA. Affected subjects, who are males, suffer from infantile onset of epilepsy and hypocalcaemia, which appears to be the result of an isolated congenital defect of parathyroid gland development; females are not affected and are normocalcaemic. The gene causing HPT has been previously mapped to a 7 cM interval, flanked centromerically by F9 and telomerically by DXS98, in Xq26-q27, and an analysis of mitochondrial DNA has established a common ancestry for these two kindreds. In order to define further the map location of HPT and thereby facilitate its isolation, we have undertaken linkage studies using polymorphic loci whose order has been established as Xcen - DXS1001 - DXS294 - DXS102 - F9 - DXS1232 - DXS984 - CDR1 - DXS105 - DXS1205 - DXS1227 - DXS98 - DXS52 - Xqter, within this region. Our results established linkage (lod score > 3) between HPT and eight of these 12 loci and indicated that the most likely location of HPT was within a 1.5 Mb interval flanked centromerically by F9 and telomerically by DXS984. Thus, the results of this study have helped to refine the map location of HPT, and this will facilitate the identification of this putative developmental gene and its role in the embryological formation of the parathyroids.

Chromosome Mapping↗

Mutational analysis of PHEX gene in X-linked hypophosphatemia.

Hypophosphatemic rickets is commonly an X-linked dominant disorder (XLH or HYP) associated with a renal tubular defect in phosphate transport and bone deformities. The XLH gene, referred to as PHEX, or formerly as PEX (phosphate regulating gene with homologies to endopeptidases on the X-chromosome), encodes a 749-amino acid protein that putatively consists of an intracellular, transmembrane, and extracellular domain. PHEX mutations have been observed in XLH patients, and we have undertaken studies to characterize such mutations in 46 unrelated XLH kindreds and 22 unrelated patients with nonfamilial XLH by single stranded conformational polymorphism and DNA sequence analysis. We identified 31 mutations (7 nonsense, 6 deletions, 2 deletional insertions, 1 duplication, 2 insertions, 4 splice site, 8 missense, and 1 within the 5' untranslated region), of which 30 were scattered throughout the putative extracellular domain, together with 6 polymorphisms that had heterozygosity frequencies ranging from less than 1% to 43%. Single stranded conformational polymorphism was found to detect more than 60% of these mutations. Over 20% of the mutations were observed in nonfamilial XLH patients, who represented de novo occurrences of PHEX mutations. The unique point mutation (a-->g) of the 5'untranslated region together with the other mutations indicates that the dominant XLH phenotype is unlikely to be explained by haplo-insufficiency or a dominant negative effect.

Amino Acid Sequence↗

High-resolution physical map of the X-linked retinoschisis interval in Xp22.

X-linked retinoschisis (RS) is the leading cause of macular degeneration in young males and has been mapped to Xp22 between DXS418 and DXS999. To facilitate identification of the RS gene, we have constructed a yeast artificial chromosome (YAC) contig across this region comprising 28 YACs and 32 sequence-tagged sites including seven novel end clone markers. To establish the definitive marker order, a PAC contig containing 50 clones was also constructed, and all clones were fingerprinted. The marker order is: Xpter-DXS1317-(AFM205yd12-DXS7175-DXS7992) -60N8-T7-DXS1195-DXS7993-DXS7174 -60N8-SP6-DXS418-DXS7994-DXS7995-DXS7996-+ ++HYAT2-25HA10R-HYAT1-DXS7997-DXS7998- DXS257-434E8R-3542R-DXS6762-DXS7999-DXS 6763-434E8L-DXS8000-DXS6760-DXS7176- DXS8001-DXS999-3176R-PHKA2-Xcen. A long-range restriction map was constructed, and the RS region is estimated to be 1300 kb, containing three putative CpG islands. An unstable region was identified between DXS6763 and 434E8L. These data will facilitate positional cloning of RS and other disease genes in Xp22.

Chromosome Mapping↗

Long-term follow-up of a phase III intergroup study of cisplatin alone or in combination with methotrexate, vinblastine, and doxorubicin in patients with metastatic urothelial carcinoma: a cooperative group study.

PURPOSE: A previously reported randomized intergroup trial demonstrated that combination chemotherapy with methotrexate, vinblastine, doxorubicin, and cisplatin (M-VAC) was superior to single-agent cisplatin in patients with advanced urothelial carcinoma. We conducted a long-term analysis of patients included in the intergroup trial to examine factors associated with long-term survival. PATIENTS AND METHODS: Two-hundred fifty-five assessable patients with urothelial carcinoma were randomized to receive either single-agent cisplatin (70 mg/m2 on day 1) or combination chemotherapy with methotrexate (30 mg/m2 on days 1, 15, and 22), vinblastine (3 mg/m2 on days 2, 15, and 22), doxorubicin (30 mg/m2 on day 2), and cisplatin (70 mg/m2 on day 2). Courses were repeated every 28 days. The association between patient characteristics and survival was assessed using Cox proportional hazards models. RESULTS: With long-term follow-up evaluation, survival in the M-VAC arm continues to be superior to cisplatin (P = .00015, log-rank test). Predictors of survival include performance status, histology, and the presence of liver or bone metastasis. Only 3.7% of the patients randomized to M-VAC are alive and continuously disease-free at 6 years. CONCLUSION: Long-term follow-up evaluation of the intergroup trial confirms that M-VAC is superior to single-agent cisplatin in patients with advanced urothelial carcinoma; however, durable progression-free survival is rare. Patients with non-transitional-cell histology, poor performance status, and/or bone or visceral involvement fare poorly and are unlikely to benefit significantly from M-VAC chemotherapy.

Aged↗

Linkage studies of a Missouri kindred with autosomal dominant spondyloepimetaphyseal dysplasia (SEMD) indicate genetic heterogeneity.

A four-generation kindred (14 affected and 10 unaffected members) from Missouri, U.S.A. in which spondyloepimetaphyseal dysplasia (SEMD) had been inherited as an autosomal dominant disorder was investigated for linkage to 13 candidate loci: COL2AI, COL9AI, COL9A2, COL9A3, COL10A1, COL11A1, COL11A2, PSACH, FGFR3, decorin, CRTL1, COMP, and PTHRP. Mutations of COL2A1, COL9A2, COL10, and FGFR3 have been reported previously in the Strudwick type of SEMD, multiple epiphyseal dysplasia type 2 (EDM2), the Schmid type of metaphyseal dysplasia, and in achondroplasia, respectively, and the pseudoachondroplasia (PSACH) locus has been mapped to chromosome 19p12. In addition, mutations in COL9 and COL11A are associated with murine forms of degenerative joint disease and chondroplasia, respectively. The family proved informative for 12 of the 13 loci and was uninformative at the decorin locus. Linkage between this form of SEMD, designated the Missouri variant, SEMDMO, and the 12 informative candidate loci was excluded (LOD scores < -2.00 at theta = 0.005 to 0.15), thereby indicating further genetic heterogeneity in these inherited disorders of bone and cartilage development.

Chromosome Aberrations↗

Construction of a YAC contig and an STS map spanning 3.6 megabase pairs in Xp22.1.

We have constructed a 3.6 Mb sequence tagged sites (STS)-based yeast artificial chromosome (YAC) contig, consisting of 58 individual YAC clones, spanning the region PDHA1 and DXS451 on Xp22.1. In addition to establishing the order of PDHA1, ISPK-1, DXS2504, DXS1528 and the 13 known polymorphic loci as Xpter-PDHA1-DXS443-DXS3424-ISPK-1-DXS12 29-DXS2504-DXS1528-DXS365-DXS7101- DXS1683-DXS1052-DXS274-DXS92-DXS1226-DX S41-DXS989-DXS451-Xcen, we have also developed 35 novel STSs from YAC end clones. These results provide a high density of STS markers (approximately 1 per 70 kb). Furthermore, a detailed long-range restriction map of the contig has been constructed with rare-cutter enzymes and this has refined and verified the physical distances between markers inferred from YAC sizes and their STS content. The integration of the physical mapping data with previous genetic mapping data and the use of STSs and non-chimeric YAC clones reported here should facilitate the construction of a transcript map of this region and the positional cloning of disease genes in this portion of Xp22.1.

Base Composition↗

Loss of heterozygosity studies at the retinoblastoma and breast cancer susceptibility (BRCA2) loci in pituitary, parathyroid, pancreatic and carcinoid tumours.

OBJECTIVE: Allelic deletion of the retinoblastoma (Rb) gene on chromosome 13 has been reported in both pituitary and parathyroid tumours. We have investigated the roles of the Rb and the hereditary breast cancer susceptibility gene (BRCA2), which lie within 25 cM of each other on chromosome 13q12-14, in the multi-step aetiology of endocrine tumours. PATIENTS AND MEASUREMENTS: Seventy-seven endocrine tumours (43 anterior pituitary, 22 parathyroid, 7 carcinoid, and 5 pancreatic islet cell tumours) with paired leucocytes have been examined for loss of heterozygosity (LOH) at the Rb and BRCA2 loci by using specific oligonucleotide primers for the PCR amplification of microsatellite polymorphisms at three intragenic Rb markers, Rb1.20, Rbi4 and D13S153, and D13S260 which is linked to the BRCA2 locus. RESULTS: Seventy-five of the 77 tumour-leucocyte pairs were informative and LOH was detected in 1 of 16 non-functioning pituitary tumours, 1 of 8 prolactinomas, 3 of 19 parathyroid adenomas and 1 of 1 parathyroid carcinoma. All the 3 parathyroid adenomas with LOH were associated with aggressive clinical and histopathological features. Allele loss was not detected in any of the 16 somatotrophinomas, 2 corticotrophinomas, 1 gonadotrophinoma, 7 carcinoid tumours (6 bronchial, 1 metastatic intestinal) or 5 pancreatic islet cell tumours that were informative. CONCLUSIONS: These results demonstrate that allelic deletions of the 13q12-14 region occur in some pituitary adenomas and 16% of parathyroid adenomas. The extensive loss, which involves both the Rb gene and the BRCA2 locus, suggests that tumour suppressor genes in this region other than Rb or BRCA2 may be involved in the development and progression of some endocrine tumours.

BRCA2 Protein↗

Clinical studies of multiple endocrine neoplasia type 1 (MEN1)

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by the combined occurrence of parathyroid, pancreatic islet and anterior pituitary tumours. To facilitate a screening programme for MEN1, we investigated 709 people (364 males and 345 females, age range 1-84 years) from 62 MEN1 families, and 36 non-familial MEN1 patients. Of those investigated, 220 (95 males and 125 females, age range 8-79 years) suffered from MEN1. Parathyroid, pancreatic and pituitary tumours occurred in 95%, 41% and 30% of the patients, respectively. Parathyroid tumours were the first manifestation of MEN1 in 87% of patients, and amongst the pituitary and pancreatic tumours, somatotrophinomas and gastrinomas were more common in patients above the age of 40 years, whilst insulinomas occurred more frequently in patients below the age of 40 years. Biochemical screening indicated that the penetrance of MEN1 by the ages of 20, 35 and 50 years was 43%, 85% and 94%, respectively, and that the development of MEN1 was confined to first-degree relatives in 91% of patients and to second-degree relatives in 9% of patients. These findings have helped to define a proposed screening programme for MEN1.

Adolescent↗

Double-blind, randomized study of primary hormonal treatment of stage D2 prostate carcinoma: flutamide versus diethylstilbestrol.

PURPOSE: Patients with stage D2 prostate carcinoma are often treated initially with hormones to decrease endogenous testosterone. Therapy with diethylstilbestrol (DES), leuprolide, or bilateral orchiectomy has been reported to be equivalent. DES is the cheapest preparation, but has the potential for serious cardiovascular or thromboembolic complications. Flutamide is a novel antiandrogen with fewer side effects. PATIENTS AND METHODS: The Eastern Cooperative Oncology Group (ECOG) conducted a double-blind, randomized study to compare the efficacy of flutamide (250 mg three times daily) to DES (1 mg three times daily) as the primary hormonal therapy for patients with stage D2 prostate cancer. Patients were stratified by performance status, disease sites, and history of cardiovascular disease at randomization. RESULTS: Forty-eight patients received DES and 44 flutamide. Patient characteristics were evenly distributed between the two treatments. The overall response rate was similar (DES, 62%; flutamide, 50%). Grade III or worse cardiovascular or thromboembolic toxicity developed in 33.3% of patients on DES and in 17.6% on flutamide (P = .051). Other toxicities were similar between the two treatment arms. However, DES produced significantly longer time to treatment failure (26.4 v 9.7 months, P = .016) and longer survival than flutamide (43.2 v 28.5 months, P = .040). CONCLUSION: As the primary hormonal therapy for stage D2 prostate cancer, DES caused more serious cardiovascular or thromboembolic complications than flutamide. Despite this, flutamide was not as active an initial agent as DES. However, the effectiveness of flutamide in conjunction with other agents compared with DES remains undetermined, and the optimal initial hormone therapy of stage D2 prostate cancer requires further studies.

Administration, Oral↗

Linkage studies in a kindred from Oklahoma, with familial benign (hypocalciuric) hypercalcaemia (FBH) and developmental elevations in serum parathyroid hormone levels, indicate a third locus for FBH.

A five-generation kindred (19 affected, two obligate carriers and 20 unaffected) from Oklahoma USA, in which familial benign (hypocalciuric) hypercalcaemia (FBH) was associated with a developmental elevation in serum parathyroid hormone (PTH) levels, has been investigated for linkage to the candidate chromosomal regions 3q21-q24 and 19p13.3, 11q13, and 11p15, to which the genes for FBH, multiple endocrine neoplasia type 1 (MEN1) and PTH have been mapped respectively. By means of 17 polymorphic markers from these regions, linkage was excluded [LOD scores < -2.00 at (theta) = 0.05-0.25]. In addition, an analysis of multipoint crossovers and use of the LINKMAP program confirmed the exclusion from these regions. Thus, this form of FBH, designated the Oklahoma variant FBH(Ok), is not linked to markers that segregate with FBH, MEN1 and PTH; our results indicate further genetic heterogeneity and the presence of a third locus for FBH.

Chromosome Mapping↗