Biomedical subjects
Publications and source records attributed to K Li.
Pharyngoesophageal reconstruction utilizing free jejunal transfer is well established. Extensive resection or debridement for extensive tumor, infection, or radiation may necessitate additional soft-tissue coverage. The authors report a successful reconstruction using a split, free, jejunal transfer to provide simultaneous pharyngoesophageal and soft-tissue coverage.
Two uracil auxotrophs of the phytopathogen Burkolderia cepacia ATCC 25416, which is known to be involved in food spoilage, were isolated by a combination of ethylmethane sulphonate and D-cycloserine counterselection. One mutant exhibited depressed orotate phosphoribosyltransferase activity while the other mutant lacked orotidine 5'-monophosphate decarboxylase activity. Pyrimidine limitation of either auxotroph elevated aspartate transcarbamoylase and dihydroorotase activities by at least 1:5-fold indicating that these pathway enzymes may be repressible by a uracil-related compound in B. cepacia. Overall, regulation of de novo pyrimidine synthesis in the uracil auxotrophs of B. cepacia ATCC 25416 was observed.
Pyrimidine synthesis in the food spoilage agent Burkholderia cepacia ATCC 25416 was investigated. The five de novo pathway enzymes of pyrimidine biosynthesis were found to be active in B. cepacia ATCC 25416 and growth of this strain on uracil had an effect on the de novo enzyme activities. The in vitro regulation of aspartate transcarbamoylase activity in B. cepacia ATCC 25416 was studies and its activity was inhibited by PP(i), ATP, GTP, CTP and UTP. The enzymes cytidine deaminase, uridine phosphorylase and cytosine deaminase were found to be active in the salvage of pyrimidines in ATCC 25416. Overall, de novo pyrimidine synthesis in B. cepacia ATCC 25416 was regulated at the level of enzyme activity and its pyrimidine salvage enzymes differed from those found in B. cepacia ATCC 17759.
The derivation of human cell lines devoid of mitochondrial (mt) DNA (rho 0) provides an opportunity to study nuclear responses to a chronic impairment of mitochondrial oxidative phosphorylation. Expression of several nuclear genes is induced in human rho 0 cells, including those encoding integral proteins of the mitochondrial inner membrane, intermediate filaments, and ribosomes. In contrast to conditions in which mitochondrial respiration is altered acutely, expression of heat shock proteins and immediate early genes is not induced. Mitochondria from rho 0 cells maintain a transmembrane electrochemical potential and are distributed within the cytoplasm of these cells in a manner indistinguishable from that of wild-type cells. We conclude that a chronic deficiency of mitochondrial oxidative phosphorylation produced by elimination of mtDNA is associated with a different pattern of gene induction than that provoked by other acute or subacute conditions that impair mitochondrial respiration or create energy demands in excess of mitochondrial respiratory capacity.
A mutation in the HSD11B2 gene has been discovered in a consanguineous Iranian family with three sibs suffering from Apparent Mineralocorticoid Excess (AME). Sequence data demonstrate a C to T transition resulting in an R337C mutation.
The products of the homeotic genes in Drosophila are transcription factors that are necessary to impose regional identity along the anterior-posterior axis of the developing embryo. However, the target genes under homeotic regulation that control this developmental process are largely unknown. We have utilized an immunopurification method to clone target genes of the Antennapedia protein (ANTP). We present here the characterization of centrosomin (cnn), one of the target genes isolated using this approach. The spatial and temporal expression of the cnn gene in the developing visceral mesoderm (VM) of the midgut and the central nervous system (CNS) of wild-type and homeotic mutant embryos is consistent with the idea that cnn is a homeotic target. In the VM, Antp and abdominal-A (abd-A) negatively regulate cnn, while Ultrabithorax (Ubx) shows positive regulation. In the CNS, cnn is regulated positively by Antp and negatively by Ubx and abd-A. Characterization of a cDNA encoding CNN predicts a novel structural protein with three leucine zipper motifs and several coiled-coil domains exhibiting limited homology to the rod portion of myosin. Immunocytochemical results demonstrate that the cnn encoded protein is localized to the centrosome and the accumulation pattern is coupled to the nuclear and centrosome duplication cycles of cleavage. In addition, evidence suggests that the expression of the cnn gene in the VM correlates with the morphogenetic function of Ubx in that tissue, i.e., the formation of the second midgut construction. The centrosomal localization of CNN and the involvement of microtubules in midgut morphogenesis suggest that this protein may participate in mitotic spindle assembly and the mechanics of morphogenesis through an interaction with microtubules, either directly or indirectly.
An assay was made on the bioactivity of the extracts of tangerine peel from Cinocitrus tangerina, orange peel from Citrus sinensis and mixed tangerine peel from Cinocitrus sp. against aphis Semia phis heraclei, Aphis craccivora, Uroleucon gobonis and Myzus persicae using residual film or topical method, and against mites Tetranychus viennensis and T. trancatus using slide-dip or immersion method. Test results show that these extracts have strong bioactivity against aphids and mites. The corrected mortality regression equations and LC50 (or LD50) of these extracts to pests are presented.
72 feet with hallux valgus among 40 patients treated by reconstruction of metatarsal arch and modified McBride operation are reported in this paper. After an average of 4.5 years of postoperative follow-up, the results showed an overall 9 degrees and 3 degrees correction of the hallux abductus angle and the intermetatarsal angle, respectively. 95% of the cases of bunions disappeared, 66% calli under the heads of the first and second metatarsal disappeared, and 91% patients were satisfied with the changes of their feet appearance.
BACKGROUND: Chronic sun exposure induces numerous changes in exposed skin; the most striking histopathologic change is the massive accumulation of material with the staining characteristics of elastin, termed solar elastosis, in the superficial dermis. Previous studies have identified elastic fibers within areas of solar elastosis, as well as a decrease in collagen content. Recently, the large chondroitin sulfate (CS) proteoglycan, versican, has been identified in the dermis in association with elastic fibers, and the smaller CS proteoglycan, decorin, has been shown to codistribute with collagen fibers. Thus, changes in expression of these CS proteoglycans might be expected in photoaging and may help to explain the clinical alterations of chronically sun-exposed skin. EXPERIMENTAL DESIGN: Immunohistochemical staining and confocal laser scanning microscopy for versican and decorin was performed on paired tissue samples from photoaged and non-sun-exposed skin taken from the same individuals. To investigate versican and decorin mRNA expression, Northern analysis was performed on paired fibroblast cultures derived from tissue explants of photoaged and non-sun-exposed skin. RESULTS: Immunohistochemical staining and confocal laser scanning microscopy revealed a massive accumulation of versican localized to the abnormally large fibers comprising solar elastosis in the superficial and mid-dermis of photoaged specimens. Decorin staining was greatly decreased within the area of solar elastosis. Similarly, changes in mRNA were measured from fibroblast cultures, with a significant increase in versican mRNA in cultures derived from photoaged skin, whereas decorin mRNA levels were significantly decreased in photoaged skin. CONCLUSIONS: This study provides further evidence for the close association of versican with elastic fibers and decorin with collagen fibers, even in the situation of abnormal fiber deposition occurring in photodamaged skin. In addition, changes in versican and decorin immunostaining are accompanied by similar alterations in gene expression.
In magnetic shield room, 9 normal subjects were measured by magnetoencephalography (MEG) and auditory evoked magnetic field (AMF) with superconducting quantum device (SQUID). In our experiment, the magnitudes of MEG were between +100 fT and -100 fT and an AMF evoked with 1 kHz tone burst had 8 stable waves. The main waves were N2, P3, N3 with latencies 65, 118, 175 ms and magnitudes -13, +15, -12 fT. The latencies of waves showed small deviations. The magnitudes of waves were about +/- 15 fT. We also found that the two lateral records of countralateral AMFs have revert waveforms in the last two subjects.
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Twenty-six patients with obstructive jaundice were investigated for RBC immune function. It was found that C3b receptor's E rosette forming rate in jaundiced patients was significantly lower than that of nonjaundiced patients, and the C3b receptor's E rosette forming inhibitory rate was higher than that of nonjaundiced patients. The RBC immune function disturbance may contribute to the postoperative sepsis in jaundiced patients.
A simple and sensitive technique to detect point mutation of the p53 gene using silver staining method for single-strand conformation polymorphism analysis of polymerase chain reaction (PCR-SSCP) is reported. In this study, the aberrations of the p53 gene (exon 6-8) in clinical specimens of primary cervical carcinoma were examined. Of 27 tumor tissues 2 samples showed mutations of p53 exon 7. Absence of abnormal bands in the p53 exon 6-8 in all ten normal cervical tissues. It appears that inactivation of p53 gene by point mutation is infrequent in clinical samples of human cervical carcinomas.
OBJECTIVE: To investigate the role of human papillomavirus (HPV) human cytomegalovirus (HCMV) infections and p53 gene mutations in the oncogenesis of cervical cancer and to clarify the association between p53 inactivation and the presence of HPV DNA. METHODS: We examined 38 primary cervical carcinomas and 21 normal cervical specimens for the presence of HPV and HCMV DNA sequences by multiple primers PCR and nest primers PCR. The structure of p53 gene (exons 6-8) was also analyzed by PCR-SSCP silver staining method. RESULTS: Mutations of p53 gene (exon 7) were detected in 2 of 38 tumors. One of the cases with p53 mutation was positive for HPV 16 and two positive for HCMV. HPV 16 and 18 infections were noted in 63.2% (24/38) of the tumors, the positive rate of HCMV was 84.2% (32/38). However, HPV 16,18 and HCMV infection occurred in 4.8% and 38.1% respectively in 21 normal cervical specimens. 21 of the 24 HPV 16,18 positive tumors were also HCMV positive, but none of the normal cervical tissues was infected with both HPV and HCMV. CONCLUSION: Detection of p53 mutations in cervical carcinoma is infrequent and apparently independent of HPV infection. Cervical carcinoma is strongly associated with HPV 16 and 18 infection. A synergistic interaction may occur between HPV and HCMV infections in the oncogenesis of cervical cancer.
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It has been known that 10 enzymatic reactions are involved in de novo biosynthesis of IMP in Salmonella typhimurium. 10 genes encoding the enzymes have been localized on the Salmonella typhimurium chromosome. Seven structure genes including pur JHD operon are negatively regulated by purR. In this study the purJHD operon containing O+ and Oc were cloned in vivo respectively. Two preliminary clones, p2-9 (O+) and pC-12 (Oc) were identified to be the hybrid plasmids carrying intact pur JHD operon by genetic complementary test and reconstruction enzyme analysis. The fragments of O+ and Oc were subcloned on to pUC19 and DNA sequence were determined directly by DNA sequencer. The DNA sequence of O+ fragment revealed that a 16 base consensus sequence (named PUR box) GCGCAAACGTTTTCGT also existed in control region of pur JHD operon in Salmonella typhimurium. The DNA sequence of Oc fragment indicated that only one base change occurred at the 14th position of PUR box(C-->T). Our result strongly support the idea that PUR box is binding region of purR protein.
There is at present no noninvasive method that reliably measures blood flow in the poorly functioning renal allograft. The present study was designed to evaluate phase-contrast cine magnetic resonance imaging (PC-cine-MRI) for this purpose. We recruited for study 18 patients who had received kidney transplants 13-66 months earlier from closely related living donors. As judged by the glomerular filtration rate, which was elevated for a single kidney (76 +/- 4 ml/min 1.73 m2), allograft function was excellent, permitting the assumption of unimpaired renal extraction of paminohippuric acid (PAH). Allograft blood flow was determined consecutively on the same day, first by the standard PAH clearance technique and they by the product of the velocity of protons and renal vein cross-sectional area using PC-cine-MRI. MRI determinations could not be completed because of claustrophobia in two patients and failure to image the terminus of the allograft vein another two. Comparison of blood flow in the remaining 14 subjects revealed the two techniques to be strongly related (r = 0.91, P < 0.001). On the average, the renal blood flow rate was similar by each method; 732 +/- 62 by PAH clearance and 703 +/- 69 ml/min by PC-cine-MRI, but the agreement among individuals between the two methods was only modest, with a 95% confidence interval of agreement from -214 to +254 ml/min. We conclude that PC-cine-MRI provides a fairly accurate and noninvasive method for determining the rate of blood flow in the transplanted kidney. With further refinement it should permit the role of depressed blood flow in a variety of acute and chronic forms of human allograft dysfunction to be elucidated in humans for the first time.
We have recently cloned and characterized the entire human 230-kDa bullous pemphigoid antigen gene, which is expressed at a relatively high level in the basal keratinocytes. A putative AP2 binding sequence (KRE2), identified in the position -1786 to -1778, was cloned in front of a heterologous thymidine kinase chloramphenicol acetyltransferase construct, and transient transfections of normal human keratinocytes indicated a marked enhancement of the promoter activity. Normal human keratinocyte nuclear extracts contained a protein, designated as keratinocyte transcriptional protein-1 (KTP-1), which complexed with the KRE2 oligomer when examined by gel mobility shift assays. This protein was not detected in human skin fibroblast or HeLa cell nuclear extracts that did, however, contain AP2. UV cross-linking studies and Southwestern analyses suggested that KTP-1 binds to DNA as a single polypeptide of approximately 110 kDa. These data suggest that KTP-1 is a DNA-binding protein clearly distinct from AP2, and this protein may be responsible for the basal keratinocyte-specific expression of the bullous pemphigoid antigen gene.