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A Hua

Publications and source records attributed to A Hua.

14 recordsLinked to original sources
PubMed2003

Gene content and organization of an 85-kb DNA segment from the genome of the phytopathogenic mollicute Spiroplasma kunkelii.

Spiroplasma kunkelii, the causative agent of corn stunt disease in maize (Zea maysL.), is a helical, cell wall-less prokaryote assigned to the class Mollicutes. As part of a project to sequence the entire S. kunkelii genome, we analyzed an 85-kb DNA segment from the pathogenic strain CR2-3x. This genome segment contains 101 ORFs and two tRNA genes. The majority of the ORFs code for predicted proteins that can be assigned to respective clusters of orthologous groups (COGs). These COGs cover diverse functional categories including genetic information storage and processing, cellular processes, and metabolism. The most notable gene cluster in this genome segment is a super-operon capable of encoding 24 ribosomal proteins. The organization of genes in this operon reflects the unique evolutionary position of the spiroplasma. Gene duplications, domain rearrangements, and frameshift mutations in the segment are interpreted as indicators of phase variation in the spiroplasma. To our knowledge, this is the first analysis of a large genome segment from a plant pathogenic spiroplasma.

Base Sequence↗
PubMed2003

An open phase I study assessing the feasibility of the triple combination: oxaliplatin plus irinotecan plus leucovorin/ 5-fluorouracil every 2 weeks in patients with advanced solid tumors.

BACKGROUND: The aim of this study was to determine the maximum-tolerated dose (MTD) and the recommended dose of irinotecan and oxaliplatin with a fixed 5-fluorouracil (5-FU)/leucovorin (LV) regimen in patients with metastatic solid tumors. PATIENTS AND METHODS: The trial was designed to evaluate escalating doses of oxaliplatin and irinotecan, starting at 60 mg/m2 and 90 mg/m2, respectively, given at day 1 with the full-dose LV5FU2 regimen, given on days 1 and 2 as follows: folinic acid 200 mg/m2 followed by 5-FU 400 mg/m2 bolus and 600 mg/m2 22 h continuous infusion, every 2 weeks. The second cohort of patients was treated at the recommended dose for oxaliplatin and irinotecan with the simplified LV5FU regimen: on day 1, a 2-h infusion of folinic acid (400 mg/m2), followed by a 10-min intravenous bolus of 5-FU (400 mg/m2), followed by a continuous infusion of 5-FU (2400 mg/m2) over 46 h. RESULTS: Thirty-four patients were treated at the following dose levels (oxaliplatin/irinotecan mg/m2): 60/90, 60/120, 85/120, 85/150, 85/180, 85/200 and 85/220 and seven patients were treated at the recommended dose with the simplified LV5FU scheme. The MTD was reached at dose level 85/220 mg/m2 but the recommended dose chosen for the second step was 85/180 mg/m2 to keep a better compliance with the biweekly schedule. Main grade 3/4 toxicities per patient included the following: neutropenia in 78% (febrile episodes in 12%), diarrhea in 27%, nausea/vomiting in 24% and peripheral neuropathy in 37% (Lévi's scale). Antitumor activity was observed at almost all dose levels. Most objective responses were observed in digestive malignancies, since 10 out of 11 were obtained in five colorectal cancers, two pancreatic cancers, two cholangiocarcinoma and one gastric cancer. CONCLUSION: The recommended dose for the triple association is 85/180 mg/m2 of oxaliplatin and irinotecan, respectively, with LV5FU2 or simplified LV5FU. The antitumor activity in gastrointestinal malignancies should be evaluated in phase II studies in different tumor types.

Adult↗
PubMed2002

High-dose, single-agent irinotecan as first-line therapy in the treatment of metastatic colorectal cancer.

PURPOSE: The efficacy and safety of single-agent, high-dose irinotecan (CPT-11, Campto) 500 mg/m(2) every 3 weeks were investigated as first-line treatment for advanced colorectal cancer (CRC). PATIENTS AND METHODS: Patients were enrolled into the study to receive a first cycle of therapy with irinotecan at a dose of 350 mg/m(2) every 3 weeks, which could be escalated to 500 mg/m(2) for the second and subsequent cycles depending on toxicity. Efficacy, safety and pharmacokinetics were determined in the intent to treat (ITT) population and the high-dose population (i.e. patients who had received at least three cycles of irinotecan, the second and third at 500 mg/m(2)). RESULTS: Of 49 patients enrolled into the study (ITT population), 31 (63%) received at least three cycles of treatment with cycles 2 and 3 at an irinotecan dose of 500 mg/m(2) (the high-dose population). The response rates (RR) for the ITT and high-dose populations were 24.5% and 35.5%, respectively. The main grade 3/4 toxicities per cycle in the ITT and high-dose populations were neutropenia 22% and 17%, febrile neutropenia 5% and 3%, and diarrhoea 12% and 7%, respectively. The pharmacokinetics of irinotecan and its metabolite SN-38 were investigated in 31 patients in cycle 1 and 22 patients in cycle 2. Irinotecan clearance and SN-38 exposure were not sufficiently correlated with toxicity in cycle 1 to identify patients for dose increase in subsequent cycles. The exposure to irinotecan and SN-38 increased in proportion to dose from 350 to 500 mg/m(2). CONCLUSION: These results suggest that high-dose irinotecan can be safely administered as first-line monotherapy to approximately two-thirds of patients who present with advanced CRC following a selective first cycle.

Adenocarcinoma↗
PubMed2002

Antitumour activity of three second-line treatment combinations in patients with metastatic colorectal cancer after optimal 5-FU regimen failure: a randomised, multicentre phase II study.

BACKGROUND: We have investigated the efficacy, safety and quality of life profiles of three therapeutic combinations [irinotecan + leucovorin (LV)/5-fluorouracil (5-FU), oxaliplatin + LV/5-FU and irinotecan +oxaliplatin] in patients with metastatic colorectal cancer after failure of a 5-FU-based regimen, or whose disease had progressed within 6 months of the end of treatment. PATIENTS AND METHODS: One hundred and one patients were randomised to receive either: (i) irinotecan 180 mg/m(2) on day 1 followed by an LV 200 mg/m(2) infusion, before a 5-FU 400 mg/m(2) bolus followed by a 5-FU 600 mg/m(2) infusion (LV5FU2 regimen), on days 1 and 2 every 2 weeks; (ii) oxaliplatin 85 mg/m(2) on day 1 followed by the LV5FU2 regimen on days 1 and 2 every 2 weeks; or (iii) oxaliplatin 85 mg/m(2) followed by irinotecan 200 mg/m(2), both on day 1 every 3 weeks. The primary end point was overall response rate (ORR). RESULTS: The intention-to-treat ORRs were 11.4% [95% confidence interval (CI) 3.2-26.7), 21.2% (95% CI 9.0-38.9) and 15.2% (95% CI 5.1-31.9), respectively, in the three arms. Tumour growth control was >or=60% for all three combinations and overall survivals were 12.2 months (95% CI 9.2-16.0), 11.5 months (95% CI 9.0-14.1) and 11.0 months (95% CI 8.1-12.2), respectively. All patients were evaluable for safety. Main grade 3-4 toxicity was neutropenia (33 to 39% of patients). CONCLUSIONS: Thus, second-line treatment with irinotecan/LV5FU2, oxaliplatin/LV5FU2 or irinotecan/oxaliplatin, provides good tumour growth control and survival coupled with an acceptable safety profile.

Adult↗
PubMed2000

Comparative sequence analysis of 634 kb of the mouse chromosome 16 region of conserved synteny with the human velocardiofacial syndrome region on chromosome 22q11.2.

Mouse genomic DNA sequence extending 634 kb on proximal mouse chromosome 16 was compared to the corresponding human sequence from chromosome 22q11.2. Haploinsufficiency for this region results in velocardiofacial syndrome (VCFS) in humans. The mouse region is rearranged into three conserved blocks relative to human, but gene content and position are highly conserved within these blocks. Examination of the boundaries of one of these blocks suggested that the evolutionary chromosomal rearrangement occurred in the mouse lineage, resulting in inactivation of the mouse orthologue of ZNF74. Sequence analysis identified 21 genes and 15 ESTs. These include 2 novel genes, Srec2 and Cals2, and previously undescribed splice variants of several other genes. Exon discovery was carried out using GRAIL2, MZEF, or comparative analysis across 491 kb of conserved mouse and human sequence. Sequence comparison was highly effective, identifying every gene and nearly every exon without the high frequency of false-positive predictions seen when algorithmic methods were used alone. In combination, these procedures identified every gene with no false-positive predictions. Comparative sequence analysis also revealed regions of extensive conservation among noncoding sequences, accounting for 6% of the sequence. A library of such sequences has been established to form a resource for generalized studies of regulatory and structural elements.

Abnormalities, Multiple↗
PubMed1999

Comparative sequence of human and mouse BAC clones from the mnd2 region of chromosome 2p13.

The mnd2 mutation on mouse chromosome 6 produces a progressive neuromuscular disorder. To determine the gene content of the 400-kb mnd2 nonrecombinant region, we sequenced 108 kb of mouse genomic DNA and 92 kb of human genomic sequence from the corresponding region of chromosome 2p13.3. Three genes with the indicated sizes and intergenic distances were identified: D6Mm5e (>/=81 kb)-787 bp-DOK (2 kb)-845 bp-LOR2 (>/=6 kb). D6Mm5e is expressed in many tissues at very low abundance and the predicted 526-residue protein contains no known functional domains. DOK encodes the p62(dok) rasGAP binding protein involved in signal transduction. LOR2 encodes a novel lysyl oxidase-related protein of 757 amino acid residues. We describe a simple search protocol for identification of conserved internal exons in genomic sequence. Evolutionary conservation proved to be a useful criterion for distinguishing between authentic exons and artifactual products obtained by exon amplification, RT-PCR, and 5' RACE. Conserved noncoding sequence elements longer than 80 bp with >/=75% nucleotide sequence identity comprise approximately 1% of the genomic sequence in this region. Comparative analysis of this human and mouse genomic DNA sequence was an efficient method for gene identification and is independent of developmental stage or quantitative level of gene expression. [The sequence data described in this paper have been submitted to the GenBank data library under the following accession numbers: AC003061, mouse BAC clone 245c12; AC003065, human BAC clone h173(E10); AF053368, mouse Lor2 cDNA; AF084363, 108-kb contig from mouse BAC 245c12; AF084364, mouse D6Mm5e cDNA.]

Amino Acid Sequence↗
PubMed1997

Disruption of the clathrin heavy chain-like gene (CLTCL) associated with features of DGS/VCFS: a balanced (21;22)(p12;q11) translocation.

The smallest region of deletion overlap in the patients we have studied defines a DIGeorge syndrome/velocardiofacial syndrome (DGS/VCFS) minimal critical region (MDGCR) of approximately 250 kb within 22q11. A de novo constitutional balanced translocation has been identified within the MDGCR. The patient has some features which have been reported in individuals with DGS/VCFS, including: facial dysmorphia, mental retardation, long slender digits and genital anomalies. We have cloned the breakpoint of his translocation and shown that it interrupts the clathrin heavy chain-like gene (CLTCL) within the MDGCR. The breakpoint of the translocation partner is in a repeated region telomeric to the rDNA cluster on chromosome 21p. Therefore, it is unlikely that the patient's findings are caused by interruption of sequences on 21p. The chromosome 22 breakpoint disrupts the 3' coding region of the CLTCL gene and leads to a truncated transcript, strongly suggesting a role for this gene in the features found in this patient. Further, the patient's partial DGS/VCFS phenotype suggests that additional features of DGS/VCFS may be attributed to other genes in the MDGCR. Thus, haploinsufficiency for more than one gene in the MDGCR may be etiologic for DGS/VCFS.

Abnormalities, Multiple↗
PubMed1981

Glomerulonephritis in leprosy.

A renal biopsy from a patient with lepromatous leprosy but no history of erythrema nodosum leprosum (ENL) showed histologic, immunofluorescent, and ultrastructural features typical of immune-complex glomerulonephritis. A literature review found reports of 187 renal biopsies from leprosy patients, with glomerulonephritis in 31% of the cases, and a variety of other renal lesions. This accumulated evidence demonstrates that, contrary to widely held opinion, there is no association between glomerulonephritis and a history of ENL. Furthermore, it suggests that glomerulonephritis in leprosy patients has a similar incidence in lepromatous and non-lepromatous cases. These observations have an important bearing on concepts regarding the pathogenesis of immune complex glomerulonephritis in leprosy and the humoral immune mechanisms in patients with leprosy.

Antigen-Antibody Complex↗
PubMed1976

The pathogenesis of hypertensive vascular changes in the rat: microscopic and ultrastructural correlation in vivo.

1. This study describes the changes observed in the rat microcirculation in vivo in the transparent tissue chamber of the rat back, during the florid hypertension produced by ligation of the rat aorta between both renal arteries. 2. Besides providing a new model for analysis of the action of therapeutic agents in hypertension, direct evidence of the variation in blood flow in hypertension is discussed. Fixation of the chamber tissues allows direct ultrastructural correlation with the altered function of particular vessels observed and recorded cinemicroscopically in vivo.

Animals↗
PubMed1975

Changing concepts in the management of hypertension.

Experience in a hypertension clinic attended by 591 patients over a 13-year period has shown marked changes in the pattern of use of hypotensive agents. Thiazides have been used throughout the period in almost all cases. Methyldopa was used for most patients for almost a decade. Since 1967 there has been a steady increase in the use of beta adrenergic blocking agents, and these are now used for over 60% of patients attending the clinic. Combination beta adrenergic blocking agents with peripheral vasilodators such as hydrallazine and prazosin have provided a very effective means of controlling the blood pressure in moderate and severe hypertension. Prazosin, a new peripheral vasodilator, has been used in the treatment of 295 patients. In most cases it has been used in combination with a thiazide diuretic and beta adrenergic blocking agent. Open studies have demonstrated that this is an effective hypot .ensive agent. Side effects are few and are counteracted by combination with a beta adrenergic blocking agent. Prazosin and hydrallazine are being compared in double-blind studies.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Early cytotoxic effects induced by bis-chloroethyl sulphide (sulphur mustard): [Ca2+]i rise and time-dependent inhibition of B77 fibroblast serum response.

Early cytotoxic events were studied on B77 fibroblasts. Cells were treated with sulphur mustard (SM) in short-term experiments in which cell viability was unchanged, as evaluated by the neutral red cytotoxicity test. This treatment was correlated to two early signs of cytotoxicity. The intracellular Ca2+ concentration [Ca2+]i level in SM-treated Fura-2-loaded fibroblasts showed a significant dose-dependent increase. This observed rise was sustained, in contrast to the Ca2+ signal induced by serum, and was already visible 5-10 min after the addition of SM to cell suspensions in vitro. Modification of the extracellular Ca2+ concentration in the medium had no effect on the cytosolic calcium rise caused by SM, suggesting release from intracellular Ca2+ pools. Furthermore, a time-dependent inhibition of the [Ca2+]i transient increase induced by growth-factors (as evaluated by the fetal calf serum (FCS) response) was observed within the first hour of exposure. These latter results suggest that early alterations of calcium distribution induced by SM could be one of the earliest markers of SM intoxication.

Animals↗