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Biomedical subjects

M N Huang

Publications and source records attributed to M N Huang.

11 recordsLinked to original sources
PubMed2001

Important ECG diagnosis-aiding indices of ventricular septal defect children with or without congestive heart failure.

In this paper we perform a statistical study of the conventional RR intervals and two newly defined PR' and RT intervals of ECG data. A quadratic classification rule is applied to extract several important ECG diagnosis-aiding indices among normal children and children with ventricular septal defect (VSD) with or without congestive heart failure (CHF). The results show that certain statistics computed from PR', RR and RT intervals are important diagnosis-aiding indices. Best classification vectors are searched for pairwise classification. Two methods, minimum distance criterion and a two-stage classification procedure, are considered for three-way classification. Furthermore, logistic regression models based on transformations of these important diagnosis-aiding indices are proposed. The receiver operating characteristic curves of the proposed models show better performance than those of linear and quadratic logistic models. In order to proceed with this study, a computer algorithm to automatically detect the three intervals is developed and the related ECG data are collected and analysed. The algorithm is also enhanced with an outlier detection procedure for the automatic measurements of the PR' and RT intervals.

Algorithms↗
PubMed2001

Free anterolateral thigh flap for extremity reconstruction: clinical experience and functional assessment of donor site.

From August of 1995 through July of 1998, 38 free anterolateral thigh flaps were transferred to reconstruct soft-tissue defects. The overall success rate was 97 percent. Among 38 anterolateral thigh flaps, four were elevated as cutaneous flaps based on the septocutaneous perforators. The other 34 were harvested as myocutaneous flaps including a cuff of vastus lateralis muscle (15 to 40 cm3), either because of bulk requirements (33 cases) or because of the absence of a septocutaneous perforator (one case). However, vastus lateralis muscle is the largest compartment of the quadriceps, which is the prime extensor of the knee. Losing a portion of the vastus lateralis muscle may affect knee stability. Objective functional assessments of the donor sites were performed at least 6 months postoperatively in 20 patients who had a cuff of vastus lateralis muscle incorporated as part of the myocutaneous flap; assessments were made using a kinetic communicator machine. The isometric power test of the ratios of quadriceps muscle at 30 and 60 degrees of flexion between donor and normal thighs revealed no significant difference (p > 0.05). The isokinetic peak torque ratio of the quadriceps and hamstring muscles, including concentric and eccentric contraction tests, showed no significant difference (p > 0.05), except the concentric contraction test of the quadriceps muscle, which revealed mild weakness of the donor thigh (p < 0.05). In summary, the functional impairment of the donor thighs was minimal after free anterolateral thigh myocutaneous flap transfer.

Adult↗
PubMed1996

1-Methylpyrrolidine-2-acetic Acid is not a Precursor of Tropane Alkaloids.

1-Methylpyrrolidine-2-acetic acid and related compounds were studied as precursors in the biosynthesis of the tropane alkaloids in Erythroxylum coca and Datura innoxia. (R,S)-[1',2-(13)C2,2-(14)C,(15)N]-1-methylpyrrolidine-2- acid, (R,S)-[1',2'-(13)C2,1'-(14)C]-1-methylpyrrolidine-2-acetic acid, (R,S) [1',2'-(13)C2,1-(14)C]-1-methylpyrrolidine-2-acetate, and (R,S)-+2'-(14)C] methylpyrrolidine-2-acetic acid N-acetylcysteamine thioester were synthesized an intact plants by leaf-planting or hydroponic-feeding. Specific incorporation of compounds into ( - )-hyoscyamine, ( - )-scopolamine, ( - )-cocaine and the biosynthetically related cuscohygrine were very low. These results indicate that 1-methylpyrrolidine acid is not an efficient precursor of tropane alkaloids.

Alkaloids↗
PubMed1992

Characterization of the human blood coagulation factor X promoter.

Blood coagulation Factor X is a serine protease required for both the intrinsic and extrinsic pathways of coagulation. The gene for Factor X spans 27 kilobases and is located on chromosome 13, in close proximity to the gene encoding Factor VII. Expression of Factor X is restricted to the liver. We have characterized the human Factor X promoter by mapping the start sites of transcription and carrying out a functional analysis of the promoter. The first 279 base pairs (bp) of 5'-flanking sequence upstream from the first AUG are sufficient to confer maximal promoter activity in HepG2 cells. Protein-binding sites within the 279-bp fragment are defined using gel mobility shift assays. Mutagenesis of two specific sequences within the 279-bp fragment (CCAAT at -120 to -116, and ACTTTG at -56 to -51), results in loss of ability to bind proteins from a HepG2 nuclear extract, and profound reduction in promoter activity of the 279-bp fragment. We conclude that these two protein-binding sites are critical for the activity of the Factor X promoter.

Base Sequence↗
PubMed1989

Functional consequences of an arginine180 to glutamine mutation in factor IX Hilo.

Factor IX Hilo is a variant factor IX molecule that has no detectable coagulant activity. The defect in factor IX Hilo arises from a point mutation in the gene such that in the protein Arg180 is converted to a Gln. Activation of factor IX Hilo by factor Xla was monitored using the fluorescent active site probe p-aminobenzamidine. Normal factor IX showed complete activation in one hour as determined by measuring the increase in fluorescence when p-aminobenzamidine bound to activated factor IX. Factor IX Hilo showed no increase in fluorescence even after 24 hours, indicating that the active site was not exposed. Polyacrylamide gel electrophoresis showed that factor IX Hilo was cleaved to a light chain plus a larger peptide with a molecular weight equivalent to a heavy chain covalently linked to an activation peptide. Amino terminal amino acid sequencing of factor IX Hilo cleaved by factor Xla showed cleavage only at Arg145-Ala146, indicating that the Gln180-Val181 bond was not cleaved and that the active site was thus not exposed. The presence of factor IX Hilo in patient plasma was responsible for the patient having a very long ox brain prothrombin time characteristic of severe hemophilia Bm. Patient plasma had an ox brain prothrombin time of 100 seconds using a Thrombotest kit, significantly prolonged over the normal control value of 45 seconds. When factor IX Hilo was depleted from patient plasma using an immunoaffinity column, the ox brain prothrombin time decreased to 41 seconds. When factor IX Hilo was added back to depleted patient plasma, to normal plasma depleted of factor IX by the same affinity column, or to plasma from a CRM- hemophilia B patient, the ox brain prothrombin time was significantly prolonged. We conclude that the Arg180 to Gln mutation in factor IX Hilo results in a molecule that cannot be activated by factor Xla. Further, our data suggest that the mutation results in a molecule that interacts with components of the extrinsic pathway to give a prolonged ox brain prothrombin time.

Amino Acid Sequence↗
PubMed1989

Molecular defect in factor IXHilo, a hemophilia Bm variant: Arg----Gln at the carboxyterminal cleavage site of the activation peptide.

A genomic DNA library and the enzymatic DNA amplification technique were used to isolate human factor IX coding sequences of a hemophilia Bm variant, factor IXHilo. A point mutation that resulted in the substitution of a glutamine (CAG) for an arginine (CGG) at amino acid 180 was found in exon VI of the factor IX gene (G----A at nucleotide 20519). This mutation alters the carboxy terminal cleavage site for the activation peptide at Arg180-Val181. The arginine residue at the activation peptide cleavage site is conserved in mouse, canine, bovine, and human factor IX, suggesting that the arginine at amino acid 180 is important for normal cleavage. Sequencing of all of the coding regions of factor IXHilo revealed no other mutations. We have also shown that the point mutation in exon VI creates a new Dde I restriction site, which, in combination with the enzymatic DNA amplification technique, provides a quick, reliable, and sensitive method for carrier detection and antenatal diagnosis in affected kindreds. This is the first report of the molecular defect in a hemophilia Bm patient with a markedly prolonged ox brain prothrombin time.

Amino Acid Sequence↗
PubMed1978

Lung resection for metastatic osteogenic sarcoma.

Osteogenic sarcoma, excluding the paraosteal osteosarcoma, has a grave prognosis, half of the patients dying within 1 year following ablative surgery of the primary lesion. Once pulmonary metastasis is detected, most patients do not survive more than 3 years. Various attempts by investigators to prolong patient survival, including surgery, chemotherapy, immunotherapy, radiation therapy, and combined modalities, have met with some success. This report is a summary of 13 patients who underwent lung resections and received adjuvant chemo- and/or immunotherapy for metastatic osteogenic sarcoma in our intstitute in the past 7 years.

Adolescent↗
PubMed1978

Lung resection for metastatic sarcoma.

Our experience with lung resection in fifty patients with metastatic sarcoma is presented. Seventeen patients underwent lung resection for solitary lung metastasis and thirty-three had multiple metastases. The overall estimated median survival of the patients was 22.2 months. Shorter tumor doubling time was found to indicate poor prognosis. The tumor-free interval, length of the waiting period, and the number of metastatic lesions removed did not influence the postoperative survival rate. Surgical therapy of solitary as well as multiple metastatic sarcoma of the lung appears to produce acceptable therapeutic results.

Adolescent↗
PubMed1978

Therapy of small cell carcinoma of the lung with hexamethylmelamine.

Hexamethylmelamine (HXM) is one of the substituted melamines derived from cyanuric chloride [1]. Previous studies with HXM have shown activity against small cell carcinoma of the lung, when it was given as a single agent [2, 3]. Because of relatively mild bone marrow toxicity, HXM was subsequently given in combination with other drugs and/or radiation therapy, in order to improve the therapeutic results. In this paper, our experience with HXM in treatment of small cell carcinoma of the lung is summarised.

Adult↗
PubMedDate not supplied

Shanxi Province cervical cancer screening study II: self-sampling for high-risk human papillomavirus compared to direct sampling for human papillomavirus and liquid based cervical cytology.

The objective of this study was to compare the sensitivity and specificity of a new method for self-sampling for high risk human papillomavirus (HPV) with direct sampling and liquid based cervical cytology. In Shanxi Province, China, 8,497 women (ages 27-56) underwent a self-sample for HPV using a conical-shaped brush placed into the upper vagina and rotated. Three to sixteen months later the women were screened with liquid-based cytology and direct HPV tests. Subjects with any abnormal test underwent colposcopy and multiple biopsies. Mean age was 40.9 years. 4.4 percent of subjects had >or=CIN II, 26% a positive self-sample and 24% a positive direct test for HPV. The sensitivity for detection of >or=CIN II was 87.5% for self-sampling, and 96.8% for the direct test (P < 0.001). The specificity was 77.2% for the self-sample and 79.7% for the direct test. With an abnormal Pap defined as ASCUS or greater the sensitivity of the Pap for the detection of >CIN II was 88.3% and the specificity was 81.2%. We conclude that self-sampling for HPV is less sensitive for >CIN II than the direct test, but similar to liquid based cytology.

Adult↗