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Biomedical subjects

J Zou

Publications and source records attributed to J Zou.

At least 109 records · Page 6Linked to original sources
PubMed1996

Evidence for a role of Hsp70 in the regulation of the heat shock response in mammalian cells.

Heat and other environmental insults (stress) cause unfolding of proteins, triggering the activation of heat shock transcription factor HSF (HSF1 in vertebrates) that, in higher eukaryotes, involves trimerization of the factor and acquisition of heat shock element (HSE) DNA-binding ability. Interaction of activated HSF1 with HSEs in promoters of genes encoding heat shock proteins (Hsps) enhances their expression. It was suggested that Hsp70 may function as the negative regulator of HSF1. In the simplest model, stress-unfolded proteins would compete with monomeric HSF1 for Hsp70 binding. This competition would result in dissociation of an HSF1-Hsp70 complex, allowing trimerization of released HSF1 monomers. In support of this model, we present evidence herein that 1) non-activated HSF1 forms a 1:1 complex with Hsp70, 2) both rates of heat-induced appearance of HSF1 oligomers and rates of disappearance of HSF1 heterodimers and monomers decrease when concentrations of unengaged Hsps are increased, and 3) transient overexpression of Hsp70 inhibits heat activation of HSF1.

Animals↗
PubMed1996

An observation on otoacoustic emission and ultrastructure of cochlea in experimental autoimmune inner ear disease.

OBJECTIVE: To acquire the detailed knowledge of immune lesion of inner ear. METHODS: A simultaneous study on physiology and ultrastructure was carried out in guinea pigs immunized with homogenous inner ear antigen. The specific antibody was analysed by a modified immunotransfer electrophoresis method. RESULTS: Three positive bands (with molecular weights of 68.0 kD, 62.7 kD and 60.1 kD) were found in all the sera of immunized animals but not in the control animals. Threshold shift of auditory brainstem response over 10dB HL was found in 42% of secondary system immunized animals and 32% of secondary endolymphatic sac (e.sac) immunized animals. Amplitude of distortion production otoacoustic emission dropped obviously in the above two groups. Transmission electron microscope showed the mitochondria of outer hair cells in the cochlea was impaired in animals with auditory disorder. CONCLUSIONS: The research suggests that the immune reaction against homogenous inner ear antigen results in dysfunction of hydroxycorticosteroid during the early stage.

Animals↗
PubMed1996

Approaches and reconstruction in skull base operation.

OBJECTIVE: To design convenient lateronasal and infrafrontal approaches or lateronasal subvolution approach to radically resect skull base tumors involving cranial cavity. METHODS: From 1987 through 1994, 22 patients with malignant tumors, 6 with benign tumors, one with a giant sphenoid sinus cyst and one with intranasal meningoencephalocele underwent the operation. Twenty-three cases had anterocranial fossa involved; 4, midcranial fossa; 2, anteromedial cranial fossa; and 1 case, posteromedial cranial fossa. Among the patients with malignant tumors, 11 underwent expansive maxillectomy and 10 had orbital contents resected. The intracranial approaches through lateronasal and infrafront (21 cases), nasal columella lateral subvolution (3 cases) and other approaches were used. RESULTS: The reconstruction of bony skull base defect in excess of 3.00 cm x 3.00 cm with total front musculocutaneous flap (8 cases), galeal and pericranial flap (5 cases) or other tissues (3 cases) has effectively prevented meningoencephalocele. Twelve cases had the dura resected in a range of 2.00 cm x 2.00 cm to 7.00 cm x 6.00 cm. Reconstruction of the dura defect with autofascia lata in 9 cases and other tissues in 3 cases effectively prevented the cerebrospinal fluid leak. Eight of 22 (36.4%) patients with malignant tumors have been alive and free of disease for 3-7 years after the operation. Six patients with benign tumors, one patient with giant sphenoid sinus cyst and one with meningoencephalocele were cured with this reconstructing method. CONCLUSIONS: Frontal musculocutaneous and pericranial flaps have advantages over free bone because of easy surviving and easy operating without occurrence of osteonecrosis and exclusive reaction.

Adolescent↗
PubMed1995

Asparagine-linked glycosylation in Schizosaccharomyces pombe: functional conservation of the first step in oligosaccharide-lipid assembly.

The gene gpt encoding uridine diphosphate N-acetyl-D-glucosamine:dolichol phosphate N-acetylglucosaminylphosphoryltransferase (L-G1PT) was isolated by screening a Schizosaccharomyces pombe genomic DNA library in lambda phage under low-stringency hybridization using the Saccharomyces cerevisiae gene ALG7 as probe. Sequencing 2.4 kb of S. pombe DNA revealed a 1338-bp open reading frame (ORF) encoding a hydrophobic protein of 446 amino acids with a predicted molecular weight of 49,852. The S. pombe protein was 50% identical to the S. cerevisiae protein and 43% identical to the protein from Chinese hamster ovary (CHO) cells. Overexpression of the gpt gene in S. pombe cells increased resistance to tunicamycin 25-fold and increased the specific activity of the enzyme in isolated cell membranes 13-fold. This was accompanied by a 50-fold increase in poly(A)+ RNA hybridizing to the gpt probe. Northern analysis indicated a single 1.8-kb message is transcribed from the gpt gene. The gpt gene is essential for viability of S. pombe. Cells containing a disrupted ORF could be rescued by an expression plasmid containing either the intact S. pombe gpt ORF or the CHO L-G1PT cDNA. The S. pombe gpt gene was mapped to chromosome 2 near top1 and ade1.

Amino Acid Sequence↗
PubMed1995

Genomic organization and expression of hamster UDP-N-acetylglucosamine:dolichyl phosphate N-acetylglucosaminyl phosphoryl transferase.

The hamster gene for uridine diphosphate N-acetyl-D-glucosamine:dolichyl phosphate N-acetylglucosaminyl phosphoryl transferase (L-G1PT) was found to extend over 6.5 kb and to contain nine exons. The exons ranged in size from 63 to 214 bp, encoding the 408 amino acid protein. The introns ranged from 85 bp to 1.4 kb. Upstream 5' sequences included two possible TATA boxes, one possible CCAAT box and at least two potential GC boxes. Heterologous expression was successful in Schizosaccharomyces pombe, and resulted in cells that were tunicamycin resistant and had 12-fold more L-G1PT activity than wild-type cells. Antiserum prepared to a hydrophilic peptide (residues 300-320) of the L-G1PT protein reacted with a 35-36 kDa protein in membrane samples from Chinese hamster ovary (CHO) cells and S. pombe cells that had increased levels of L-G1PT activity. In both cases, antigenic peptide competed with the 35-36 kDa protein detected by the antiserum.

Animals↗
PubMed1995

Alteration of seed fatty acid composition by an ethyl methanesulfonate-induced mutation in Arabidopsis thaliana affecting diacylglycerol acyltransferase activity.

In characterizing the enzymes involved in the formation of very long-chain fatty acids (VLCFAs) in the Brassicaceae, we have generated a series of mutants of Arabidopsis thaliana that have reduced VLCFA content. Here we report the characterization of a seed lipid mutant, AS11, which, in comparison to wild type (WT), has reduced levels of 20:1 and 18:1 and accumulates 18:3 as the major fatty acid in triacylglycerols. Proportions of 18:2 remain similar to WT. Genetic analyses indicate that the fatty acid phenotype is caused by a semidominant mutation in a single nuclear gene, designated TAG1, located on chromosome 2. Biochemical analyses have shown that the AS11 phenotype is not due to a deficiency in the capacity to elongate 18:1 or to an increase in the relative delta 15 or delta 12 desaturase activities. Indeed, the ratio of desaturase/elongase activities measured in vitro is virtually identical in developing WT and AS11 seed homogenates. Rather, the fatty acid phenotype of AS11 is the result of reduced diacylglycerol acyltransferase activity throughout development, such that triacylglycerol biosynthesis is reduced. This leads to a reduction in 20:1 biosynthesis during seed development, leaving more 18:1 available for desaturation. Thus, we have demonstrated that changes to triacylglycerol biosynthesis can result in dramatic changes in fatty acid composition and, in particular, in the accumulation of VLCFAs in seed storage lipids.

Acyltransferases↗
PubMed1995

[Analysis of antigenity of membranous labyrinth proteins of guinea pigs].

An electrophoretic dot immunobinding assay and a modified western blotting method were established. The components and antigenity of the membranous labyrinth proteins of guinea pigs were analysed. There are the same epitopes between some components of the antigen, between the antigen and extractives of acoustic nerve, cochlear nuclei, kidney and Klebsiella pneumoniae. The antigen distributes in stria vascularis, spiral ligament, spiral ganglion, the organ of Corti and Reissner's membrane etc.

Animals↗
PubMed1995

[Audiological test results of the autoimmune sensorineural hearing loss].

Audiological test results of 71 cases (130 ears) of clinically diagnosed autoimmune sensorineural hearing loss were analysed. Their audiograms can be divided into 4 types: low-frequency loss (55 ears), flat-type (26 ears), bell-type (17 ears) and high-frequency loss (32 ears). The test results of TEOAE, ABR, and -SP/AP amplitude ratio showed that the site of lesions in most of the low-frequency loss were retrocochlear, and most of the other three types were cochlear. Since about 1/3 of cases were chiefly involved retrocochlearly, the term "Autoimmune inner ear diseases" should not be used to substitute "Autoimmune sensorineural hearing loss".

Adolescent↗
PubMed1995

[Clinical evaluation of the vulva reconstruction with myocutaneous flap transposition after radical vulvectomy].

Thirty-three cases with carcinoma of vulva were treated in the division of gynecologic oncology from July, 1989 to April, 1994. Out of 33 cases, 18 with stage II or III underwent radical vulvectomy, pelvic and inguinal lymphadenectomy. These were divided into 3 groups based on the different methods of vulval reconstruction: (1) simple suture group (6 cases); (2) cutaneous flap group (4 cases); (3) myocutaneous flap transposition group (8 cases). The large defect area left by radical vulvectomy and inguinal lymphadenectomy was reconstructed by myocutaneous flap, tensor fascia latae flap, in 6 cases and musculus gracilis myocutaneous flap in 2 cases. All the cases in group 1, 2 suffered from breakdown of wounds, infection or necrosis, resulting in long term hospitalization (mean duration 36.3 days), delayed scar pains, and problems in walking or sexual activity. Primary wound-healing was observed in the 6 cases of group 3, wound infection occurred in one case with diabetes and one case of relapse cancer after radiation therapy. The mean duration of hospitalization in group 3 was 20 days, and neither scar pains nor problems in sexual activity was found after a follow up of 6 months to 4 years. One case in this group died of brain metastases of cancer of vulva. The indications and advantages of myocutaneous flap transposition are discussed. It is suggested that myocutaneous flap transposition surgery is clinically one of the best and safest methods for reconstruction of the vulva and it can improve the quality of life.

Adult↗
PubMed1995

[Laboratory diagnosis of autoimmune sensorineural hearing loss with modified western blotting method].

Anti-membranous labyrinth proteins antibody were tested in suspectable autoimmune sensorineural hearing loss (ASNHL) with a modified western blotting method. 5 strongly positive bands (including 68,000) existed in at most 18 of 25 cases (72%). This method was found to be more sensitive than the routine one (40%). Anti-membranous proteins of Klebsiella pneumoniae antibodies were also found in 7 of 9 tested patients.

Adolescent↗
PubMed1994

Removal/neutralization of hepatitis A virus during manufacture of high purity, solvent/detergent factor VIII concentrate.

Recent reports have suggested an increased risk of type A viral hepatitis in hemophilic patients treated with high purity factor VIII concentrates prepared using ion exchange chromatography coupled with solvent/detergent treatment for inactivation of viruses. To determine the capacity for removal or inactivation of hepatitis A virus during the factor VIII manufacturing process, human plasma and various factor VIII production intermediates were spiked with cell culture-propagated virus and subjected to scaled down conditions mimicking the manufacture of solvent/detergent factor VIII. The combination of antibody-mediated neutralization, cryoprecipitation, anion exchange chromatography, and lyophilization in the absence of sucrose resulted in a minimal reduction of 5.5 to 8.55 log10 in the infectivity of hepatitis A virus.

Animals↗