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Biomedical subjects

K Li

Publications and source records attributed to K Li.

At least 361 records · Page 20Linked to original sources
PubMed1993

The human 230-kD bullous pemphigoid antigen gene (BPAG1). Exon-intron organization and identification of regulatory tissue specific elements in the promoter region.

The 230-kD bullous pemphigoid antigen (BPAG1), a hemidesmosomal protein, is encoded by a gene at the human chromosomal locus 6p11-12. We have elucidated the exon-intron organization of the entire human BPAG1 gene, including approximately 2.6 kb of 5'-flanking DNA. Seven overlapping genomic clones, spanning approximately 20 kb, contained the entire approximately 9 kb coding sequence of BPAG1 and consisted of 22 separate exons, which varied from 78 to 2,810 bp in size. The 5' flanking region of DNA, upstream from the ATG initiation codon for translation, was found to contain several putative transcriptional response elements. Most interestingly, two motifs potentially conferring keratinocyte specific expression to the gene were detected. The presence of such elements was suggested by approximately 20-fold higher expression of a promoter/chloramphenicol acetyl transferase (CAT) construct in normal human epidermal keratinocytes that express the endogenous gene, as compared to several non-expressing cell types. Transient transfections with 5'-deletion clones of the promoter/reporter gene (CAT) constructs identified a region containing a putative tissue specific element, KRE2, which also conferred tissue specificity to the expression of the truncated promoter downstream from this element, however, a mutated derivative of KRE2 was not functional. Detailed knowledge of the structure and regulation of the BPAG1 gene will aid in further elucidation of diseases affecting the cutaneous basement membrane zone.

3T3 Cells↗
PubMed1993

[The role of hemorheologic disturbance in experimental acute pancreatitis].

The role of hemorheologic disturbance in experimental acute pancreatitis was studied in Wistar male rats. It was found that pancreatic duct obstruction with secretin stimulation could induce acute interstitial pancreatitis (AIP), but when high molecular dextran intravenous injection being added, acute necrotizing pancreatitis (ANP) was induced. The authors suggest that the high molecular dextran can increase blood viscosity, aggregation of erythrocytes and decrease erythrocyte deformability, which results in pancreatic microcirculatory disturbances and promotes progressive pancreatic necrosis. Hemorheologic disturbance is one of the key factors in the pathogenesis of ANP.

Acute Disease↗
PubMed1993

Predictors for prognosis of chronic myelocytic leukemia.

Bone marrows from 30 newly diagnosed Ph+chronic myelocytic leukemia (CML) (21 in chronic phase, CML-CP, 9 in accelerate phase, CML-AP) and 8 followed up patients in blast crisis (CML-BC) were tested by DNA strand breaks (%D value), DNA-aneuploidy, flow cytometry-cell surface antigen expression for CD15 and HLA-DR ratio. Our results showed that all these three parameters changed as the disease escalated. A very low value of %D and DNA-aneuploidy occurrences were high risk factors. Cell surface antigen expression CD15 and HLA-DR ratio measurement was simple and reliable. The ratio < 1.0 appeared earlier than morphology clarifying CML-AP and should be followed up regularly.

Aneuploidy↗
PubMed1993

[Synthesis and antifungal activity of 1-(2-[(4-substituted-phenyl) methoxy]-2-(substituted-phenyl) ethyl)-1H-azoles].

Twenty nine 1-(2-[(4-substituted-phenyl) methoxy]-2-(substituted-phenyl) ethyl)-1H-azoles were synthesized for searching of more potent and less toxic antimycotic agents. Nine of the title compounds are first reported. Results of preliminary biological tests showed that most of the title compounds exhibited activity against the common pathogenic fungi such as Candida albicans, Microsporum bodin, Trichophyton gypsum, Epidermophyton floccosum, Trichophyton violaceum, Microsporum ferrugincum, Trichophyton rubrum and Microsporum gypsum. The antifungal activity of compound 14 was roughly comparable to clotrimazole and econazole against Candida albicans, but was more active against other test fungi than clotrimazole and econazole. Compounds 4, 5, 6, 12, 23 also have good antifungal activity, but are less active against Candida albicans.

Antifungal Agents↗
PubMed1993

Aberration antigen expression in adult acute myelocytic leukemias.

Marrows from 58 newly diagnosed acute myelocytic leukemia (FAB-AML) patients were immunophenotyped by flow cytometry with 13 kinds of monoclonal antibodies. Marrows of 53.4% of the patients showed pure myeloid antigen expression (Ly-AML) and 34.5% displayed both myeloid and lymphocyte associated antigen expression (Ly+AML). In general, fluorescence intensity of lymphocyte associated antigen in Ly+AML was weaker than that of myeloid antigen. Myeloid and lymphoid marker cells distributed randomly in DNA-aneuploidy. It took more days to reach the first complete remission in Ly+AML. The aberration antigen expression in AML allows a sensitive detection of minimal residual leukemic cells in complete remission bone marrow and treatment stratification.

Adolescent↗
PubMed1993

[Analysis on postoperative prognosis in relation to blood ketone body ratios in surgical patients with liver disease].

Eighty-one patients with liver disease were studied for the postoperative changes in the arterial blood ketone body ratio (KBR) and routine liver function tests. The postoperative patients were classified into three groups-according to the postoperative changes in KBR. In the 54 patients of group A, KBR did not decrease to below 0.7, only 2 cases with complications (3.7%); in the 25 patients of group B, KBR decreased transiently to 0.4-0.7 and then increased to over 0.7, 9 cases with complications (36.0%), but they were ameliorated concomitantly with the restoration of KBR; in the 2 cases of group C, KBR decreased irreversibly to below 0.4, and a variety of complications occurred, so the patients finally died of multiple organ failure (MOF). It was found that routine liver function tests were less reliable direct indicators for the onset of postoperative hepatic insufficiency than KBR, which reflected the oxidoreduction state of liver mitochondria.

Adult↗
PubMed1993

Production of a bifunctional hybrid molecule B72.3/metallothionein-1 by protein engineering.

A hybrid anti-tumour B72.3 antibody/metallothionein protein B72.3MT-1 was produced by the construction of the expression vector mpSV2neo-EP1-B72.3MT-1. This vector contained the neo gene as a selection marker, the murine immunoglobulin promoter and enhancer, and the hybrid B72.3 heavy chain gene fragment with mouse metallothionein-1 cDNA gene ligated into its CH2 domain. The expression vector was transfected to the heavy chain loss mutant B72.3Mut(K) cell line. The hybrid protein B72.3MT-1 was purified from transfectant supernates using a Protein G column. We showed that the hybrid protein retained the binding reactivity for the TAG72 antigen as the original B72.3 antibody, and the metal-binding capacity of the native metallothionein molecule. Therefore, the bifunctional hybrid protein B72.3MT-1 may be very useful in cancer imaging when labelled with radionuclides such as 99mTc.

Adenocarcinoma↗
PubMed1992

Transcriptional control of nuclear genes for the mitochondrial muscle ADP/ATP translocator and the ATP synthase beta subunit. Multiple factors interact with the OXBOX/REBOX promoter sequences.

The OXBOX promoter regions of the genes for the muscle-specific adenine nucleotide translocator (ANT1) and the beta subunit of the ATPsynthase (ATPsyn beta) have been implicated in the increased transcription of these nuclear-encoded oxidative phosphorylation (OXPHOS) genes in heart and skeletal muscle. DNA binding, electrophoretic mobility shift (gel-shift) assays now reveal that the OXBOX region has two unique but overlapping elements, the 13-base pair (bp) OXBOX and an 8-bp REBOX. The OXBOX binding factors are found only in myogenic cell lines, whereas the REBOX factors are ubiquitous. Methylation interference experiments have defined the boundaries of the OXBOX and REBOX elements, confirmed that the OXBOX factors are muscle-specific, and shown that the OXBOX and REBOX factors do not bind concurrently. The binding of the REBOX factors was found to be sensitive to NADH and thyroxine, suggesting that it may modulate OXPHOS gene expression in response to environmental and hormonal changes. Hence, the OXBOX/REBOX complex provides one mechanism by which mammalian energy metabolism can be adapted to developmental and environmental demands.

Animals↗
PubMed1992

Determination of sialic acids in human serum by reversed-phase liquid chromatography with fluorimetric detection.

A simple, rapid and highly sensitive reversed-phase liquid chromatographic method has been developed for the determination of sialic acids in human serum. The sialic acids, released by hydrolysis of serum, are converted in borate buffer with malononitrile to highly fluorescent compounds. The reaction mixture is separated isocratically within 5 min using an octadecyl-bonded silica column and a mobile phase of methanol and ammonium acetate buffer (15:85, v/v; pH 5.5). Measurement of the fluorescence intensity of the reaction mixture at 434 nm with irradiation at 357 nm allowed determination of 30-1000 ng/ml of sialic acids with high reproducibility. The limit of detection was 2 ng/ml. Intra-day and inter-day coefficients of variation for assaying 300 ng/ml N-acetylneuraminic acid (NANA) were 1.5% (n = 9) and 2.6% (n = 7), respectively. The recoveries of NANA were 98.5-101.1% for serum. The method has been used for clinical determinations.

Chromatography, High Pressure Liquid↗
PubMed1992

Third ventricular pineal gland grafts in the gerbil: an electron microscopical and immunohistochemical investigation.

The superficial pineal gland was grafted into the third ventricle of adult Mongolian gerbils. Donor pineal glands from both neonatal and 3-4 week old gerbils were able to survive for at least 6 months. The pinealocytes of the grafted superficial pineal glands maintained the morphology and the S-antigen immunoreactivity of the in situ pineal complex. Synaptic ribbons and spherules were present but rare. Unlike the in situ pinealocytes, glycogen accumulations were common in the graft pinealocytes. Site specific modulation of structure was indicated as the ventricular surface of the grafts became covered with cerebrospinal fluid (CSF)-contacting pinealocytes typical of those seen in the deep pineal. The CSF-contacting pinealocytes of the graft had numerous processes that extended along the ventricular surface of the graft. The blood vessels of the grafts had non-fenestrated endothelium and wide perivascular areas typical of those seen in the in situ pineal complex. Tyrosine hydroxylase-immunopositive nerve fibers were present in the grafted tissue indicating reinnervation of the graft. The source of the fibers was not determined. The nerve fibers were present both within the perivascular area and within the parenchyma where they were associated with pinealocytes. The results demonstrate that the cerebral ventricles are an ideal location for the survival of superficial pineal gland grafts. It is suggested that pineal grafts may be a means to further study pineal development and innervation.

Animals↗
PubMed1992

Benextramine-neuropeptide Y (NPY) binding site interactions: characterization of 3H-NPY binding site heterogeneity in rat brain.

Pre-incubation of rat brain membranes with 200 microM benextramine followed by extensive dilution and washing to remove unbound ligand reduced Bmax for N-[propionyl-3H]-NPY (3H-NPY) specific binding by 61% relative to control membranes treated identically but in the absence of benextramine. When rat brain membranes were co-incubated with 3H-NPY and 57 microM benextramine, there was a significant shift to the right; the apparent Kd for 3H-NPY binding increased two-fold relative to control membranes. These data are consistent with the hypothesis that benextramine is a competitive and irreversible ligand for a population (60-65%) of rat brain NPY binding sites. 'Paired tube' assays were then used to determine the selectivity of these benextramine-sensitive and insensitive 3H-NPY binding site populations. PYY, NPY and NPY13-36 each displaced 100% of 3H-NPY from rat brain membrane binding sites both in the absence and presence of 1 mM benextramine. In contrast, [Leu31,Pro34]NPY displayed the same binding site selectivity as benextramine in displacing 65% of 3H-NPY from specific binding sites on untreated rat brain membranes, and it failed to displace 3H-NPY from membranes treated with 1 mM benextramine. Thus the selectivity of the benextramine-insensitive 3H-NPY binding site population--PYY > = NPY > NPY13-36 >> [Leu31,Pro34]NPY--is characteristic of a Y2-like NPY binding site population, while the benextramine-sensitive 3H-NPY binding sites appear to be a Y1-like binding site population.

Amino Acid Sequence↗
PubMed1992

Cloning of partial cDNA for mouse 180-kDa bullous pemphigoid antigen (BPAG2), a highly conserved collagenous protein of the cutaneous basement membrane zone.

One-hundred-eighty kilodalton bullous pemphigoid antigen (BPAG2) is recognized by autoantibodies in the sera of patients with blistering skin diseases, bullous pemphigoid (BP), and herpes gestationis (HG). In this study, we have screened a mouse epidermal keratinocyte cDNA library with a 1.0-kb human BPAG2 cDNA, which has been shown to correspond to two collagenous domains (Giudice et al: J Clin Invest 87:734-738, 1991). Screening of the mouse library identified two cDNA clones, the larger one being 1.8 kb in size. Comparison of the mouse amino acid sequences, as deduced from cDNA, with the corresponding human sequences revealed 86% homology. Furthermore, Northern hybridizations of mouse epidermal RNA with these cDNA revealed the presence of an mRNA transcript of approximately 6 kb, the size of the human BPAG2 mRNA. Elucidation of the deduced amino-acid sequences revealed the presence of definitely one and possibly two putative membrane-associated segments, suggesting that the 180-kDa BP antigen is a transmembrane protein. The sequence analysis also identified a 7-amino-acid segment that was predicted by computer analysis to be antigenic. Elucidation of the divergence between the mouse and previously published human and chicken BPAG2 sequences indicated that this protein segment was relatively well conserved. These data suggest, therefore, that the 180-kDa bullous pemphigoid antigen associated with hemidesmosomes is a well-conserved transmembrane protein that may play a critical role in the attachment of epidermis to the underlying basement membrane.

Amino Acid Sequence↗
PubMed1992

Immunohistochemical characterization of amyloid proteins in sural nerves and clinical associations in amyloid neuropathy.

To test whether immunohistochemical characterization of proteins in amyloid deposits in biopsied sural nerves gives reliable and useful diagnostic information using commercially available reagents, biopsy specimens of sural nerves from 38 patients with amyloid neuropathy were studied. Transthyretin (TTR) was detected in the amyloid deposits of 11 nerves, lambda light chains (LC) in 8 nerves, kappa LC in 7 nerves, and both lambda and kappa LC in 3 nerves. In 9 nerves, the amyloid deposits were too small to allow adequate immunohistochemical characterization of amyloid proteins in serial sections. Evidence that immunohistochemical characterization was correct came from: 1) evaluation of kin, 2) search for monoclonal proteins in the plasma, and 3) sequencing of the gene abnormalities in TTR+ cases. In 9 of 11 TTR+ cases, in which DNA could be obtained, sequencing of the gene showed that each of the 9 cases was heterozygous for a gene mutation; 7 had previously described mutations and 2 undescribed mutations. Therefore, in the nine sporadic cases without plasma monoclonal light chains, the immunohistochemical characterization correctly identified the protein in amyloid as transthyretin. Likewise, there was a high concordance between immunoglobulin light chains in plasma and light chains in amyloid in primary amyloidosis. Evaluation of the type, distribution, and severity of the neurologic symptoms and deficits showed: 1) the sensorimotor and autonomic neuropathy of amyloidosis characteristically affects proximal as well as distal limbs, and 2) the type of amyloidosis probably cannot be determined from the characteristics or severity of the neuropathy alone or from the location or size of amyloid deposits in nerve.

Aged↗
PubMed1991

Human bullous pemphigoid antigen (BPAG1). Amino acid sequences deduced from cloned cDNAs predict biologically important peptide segments and protein domains.

Bullous pemphigoid antigens are defined as the autoantigens in a blistering skin disease, bullous pemphigoid. One of them, a 230-kDa protein (BPAG1), is associated with hemidesmosomes, attachment complexes at the basal keratinocyte-lamina lucida interface within the dermal-epidermal basement membrane zone. The precise functions and cellular compartmentalization of BPAG1 are unknown. In this study, a human keratinocyte lambda gt11 cDNA library was screened for clones corresponding to BPAG1. The composite of overlapping cDNAs delineated 8,930 base pairs of nucleotide sequences that contained an open reading frame encoding 2,649 amino acids. Analysis of the deduced amino acid sequences predicted a putative signal peptide of 43 amino acids and the presence of a membrane-associated sequence of 17 amino acids. Several potential sites for N-glycosylation, as well as for protein kinase C or cAMP- and cGMP-dependent protein kinase-mediated phosphorylation were identified. Three peptide segments were predicted to be highly antigenic, potentially serving as epitopes for the formation of autoantibodies. Eight repeat segments of 38 residues each with a high degree of homology with sequences in desmoplakin I, a component of desmosomal cytoplasmic plaques, were detected in the carboxyl-terminal end of the molecule. In addition, the presence of three subdomains characterized by heptad repeats predicted an alpha-helical coiled coil dimer structure in the central portion of the protein. These data suggest that BPAG1 may be a membrane-associated protein that plays a role in the attachment of basal keratinocytes to the underlying basement membrane.

Amino Acid Sequence↗
PubMed1991

S-antigen and glial fibrillary acidic protein immunoreactivity in the in situ pineal gland of hamster and gerbil and in pineal grafts: developmental expression of pinealocyte and glial markers.

Postnatal development of S-Ag and GFAP immunoreactivity in the in situ pineal glands of golden hamsters and gerbils was examined using the avidin-biotin-peroxidase immunohistochemical technique. S-Ag was present in the gerbil pineal gland on the first postnatal day (P1), whereas it did not appear in the hamster pineal until P6. GFAP-immunoreactive astrocytes were first observed in the hamster pineal gland on P7 and in the gerbil pineal gland on P10. The number of S-Ag-immunoreactive pinealocytes and GFAP-immunoreactive astrocytes in the pineal glands of hamsters and gerbils increased with increasing age from P7 to 3 weeks. By 4 weeks, strong S-Ag and GFAP immunoreactivity was observed in both hamster and gerbil pineal glands. GFAP-immunoreactive stellate astrocytes were distributed evenly throughout the gerbil superficial pineal gland, but they were more often located in the peripheral region of the hamster superficial pineal. For the pineal grafts, pineal glands from neonatal (3-5 day old) hamsters were transplanted into the third cerebral ventricle (infundibular recess or posterior third ventricle) or beneath the renal capsule of adult male hamsters. S-Ag immunoreactivity appeared in the pineal grafts within 1 week following transplantation. By 4 weeks the pineal grafts showed strong S-Ag immunoreactivity which was maintained until at least 12 weeks after transplantation. The time course of glial cell maturation in the cerebroventricular pineal grafts is generally parallel to the hamster pineal gland in situ before 4 weeks. By 12 weeks, however, more astrocytes differentiated and developed GFAP-immunoreactivity in the pineal grafts than in the in situ pineals. These studies have described the postnatal development of S-Ag and GFAP immunoreactivity in in situ pineal glands and in neonatal pineal grafts.

Animals↗