Biomedical subjects

M Lin

Publications and source records attributed to M Lin.

At least 145 records · Page 8Linked to original sources

PubMed2000

[Study on the revision of hygiene standard for fresh-cream cake].

In order to revise the hygiene standard for fresh-cream cake, 44 samples were examined. With regard to the specific selling condition and the results inspected, a reference for acid value, peroxide value, bacterial colony forming efficiency and mould count was proposed. Moreover the yeast count was suggested as one of the hygienic standard for GB7099 too. The result of this study could be used as a reference for developing the law on the hygienic inspection and control of fresh-cream cake.

Bread↗

PubMed2000

[The expression of PCNA and NOR in carcinogenesis procession of hamster buccal pouch mucosa].

OBJECTIVE: To investigate the expression of proliferating cell nuclear antigen (PCNA) and nucleolar organizer regions (NOR) with the carcinogenesis model of hamster buccal pouch mucosa. METHODS: 48 Syrain hamsters with 6-8 weeks old and 70-80 g weight were selected. The material used for inducing cancer is 0.5% DMBA (7,12-dimethylbenzanthracene) in acetone. 0.5% DMBA was applied in the right buccal pouch of the hamster 3 times a week for 12 weeks. The control received no treatment. The time for collecting specimens was 3, 6, 9 and 12 weeks. The specimens were immediately fixed with 10% formalin, dyed with HE, and then two doctors major in histopathology evaluated with the WHO criterion (1986). The wax of immunohistochemical specimen was cut and placed on the APES pieces of glass, treated with 50 degrees C for 2 hours and preserved under the indoor temperature. The PCNA was examined with the LSAB technique of immunohistochemistry. The company called Zymed provided the MonAb. The positive control was a sample of human inflammatory hyperplastic lymphoma, and the negative was PBS replacing the MonAb. NOR count was determined in a method of silver nitrate staining. The test condition should be at 45 degrees C without light. RESULTS: 1. AgNOR was usually located in the basal-cell layer of normal epithelium, mainly in a single form. High dysplasia was mainly in an aggregated form, however, carcinoma in infiltration appeared to be in a mixed form. 2. PCNA expression was similar to that of the normal control in hyperplastic epithelia (3 weeks) at a moderate level in dysplasia epithelia (6-9 weeks). PCNA expressed highly in squamous cell carcinoma. The expression of the PCNA in line with malignant progress became stronger increasingly. The positive cell was perceivable in all epithelia of high dysplasia. CONCLUSION: PCNA has been significantly positive and correlative with AgNOR (r = 0.635, P < 0.001), however, the film of PCNA is much clearer and the practical value is greater.

Animals↗

PubMed2000

[Tn5 mutagenesis and the characteristics of indole-3-acetic acid biosynthesis in Alcaligenes faecalis A1501].

The IAA production of Alcaligenes faecalis wild type strain A1501 depended on addition of L-tryptopham(trp). A1501 could grow well in minimal medium without Trp, but could not produce IAA. The results indicated that there was Trp-dependent IAA biosynthesis pathway in A. faecalis A1501. A1501 shows a characteristic of cell density-dependent IAA biosynthesis. The Tn5-induced mutant bank of A1501 was constructed using Tn5 mutagenesis and one Trp auxotrophic mutant AT63 was selected and identified. The Tn5-induced mutant AT63 could synthesis 2.24 micrograms/mL IAA in minimal medium without L-Trp. It indicated there were at least two IAA biosynthesis pathways in A. faecalis, one needed Trp, the other needed IGP as precursor. The results of southern hybridization also suggested that the Tn5-insertion might locate in gene locus encoded IAA synthetase.

Alcaligenes faecalis↗

PubMed2000

The preliminary study of interferon-gamma gene transfection to human Tenon's capsule fibroblasts in vitro.

PURPOSE: To investigate the results of the interferon-gamma (IFN-gamma) gene transfer and transient expression in human Tenon's capsule fibroblast in vitro in order to find a way to gene therapy in vivo. METHOD: Using LipofectAMINE, IFN-gamma gene was transferred in human Tenon's capsule fibroblasts with plasmid pcDNA3 IFN-gamma. Its mRNA transcription and protein expression were determined by RT-PCR and flow cytometry assay respectively. RESULT: The human Tenon's capsule fibroblasts transferred the IFN-gamma gene can express the IFN-gamma in transcription and protein level transiently. CONCLUSION: IFN-gamma gene can be transferred successfully and expressed expressed efficiently in human tenon's capsule fibroblast in vitro.

Conjunctiva↗

PubMed2000

New management of angle-closure glaucoma by phacoemulsification with foldable posterior chamber intraocular lens implantation.

OBJECTIVE: To investigate the management of angle-closure glaucoma by phacoemulsification with foldable posterior chamber intraocular lens (PC-IOL) implantation. DESIGN: Retrospective, noncontrolled interventional case series. PARTICIPANTS: In 36 eyes with angle-closure glaucoma (ACG), there were 18 eyes with primary acute angle-closure glaucoma (PACG), 14 eyes with primary chronic angle-closure glaucoma (PCCG), 3 eyes with secondary acute angle-closure glaucoma (SACG) and 1 eye with secondary chronic angle-closure glaucoma (SCCG). INTERVENTION: Phacoemulsification with posterior chamber intraocular lens implantation. MAIN OUTCOME MEASURES: Postoperative visual acuity, IOP, axial anterior chamber depth. RESULTS: After a mean postoperative follow-up time of 8.81 +/- 7.45 months, intraocular pressure was reduced from a preoperative mean of 23.81 +/- 17.84 mmHg to a postoperative mean of 12.54 +/- 4.73 mmHg (P = 0.001). Mean anterior chamber depth was 1.75 +/- 0.48 mm preoperatively and 2.29 +/- 0.38 mm postoperatively (P = 0.000). Best spectacle-corrected visual acuity in 36 eyes ranged from 0.01 to 0.7 (20/200 to 20/30) postoperatively, which was better than preoperative VA ranging from hand movement to 0.4 (20/50) (P = 0.000). CONCLUSION: Phacoemulsification with posterior chamber foldable intraocular lens implantation can be a good alternative in treating angle-closure glaucoma.

Aged↗

PubMed2000

The analysis of pedigree GZ (Guangzhou). 1 with primary open angle glaucoma.

PURPOSE: To analyze the hereditary modality of primary open-angle glaucoma in China. METHODS: The genetic form of Pedigree GZ. 1 was analyzed using Mandalian hereditary rules. RESULTS: Pedigree GZ. 1 had following characteristics: 1) The pedigree had four generations, and there existed POAG patients in each generation; 2) Each patient had a parent with POAG. If the parents didn't suffer from the disease, their children would not. 3) The incidence of POAG in the relatives of the patients was 1/2. In addition, The age of onset, intraocular pressure, fundus and prognosis was different from each other in the patients. CONCLUSIONS: 1) Pedigree GZ. 1 is inherited as an autosomal dominant trait. 2) There exists individual differences of clinical manifestations in POAG patients.

Adolescent↗

PubMed2000

[The cultivation, freezing-state preservation and resuscitation of human iris pigment epithelial cells in vitro].

PURPOSE: To establish the culture of human iris pigment epithelial cells in vitro and study the freezing-state preservation and resusciation. METHODS: The iris pigment epithelial specimens from human eyes were cultured in vitro. Based on the cell-frozen principle, the cultured cells were collected, then frozen in liquid nitrogen and resuscitation. RESULTS: Cultured iris pigment epithelial cells were obtained. Under the inverted light microscope, primary cells appeared multigonal and arranged in monolayer, there were abundant pigment granules in the cytoplasm and the nuclei each of which contained 1 or 2 nuceoli wre relatively transparent. Under the transmission electron microscope, there were plenty of microvilli at the cell membrane and desmosomes present in the intercellular space. 6 groups of cells were frozen. The resuscitation exeriment was carried out for 4 times, every times being successful. All of the resuscitated rates were more than 90%. CONCLUSION: The human iris pigment epithelial cells were cultured in vitro successfully, they can also be frozen and resuscitated, which will be useful in studies of pathogenesis for some eye disease.

Cells, Cultured↗

PubMed2000

[The culture and cryopreservation of human conjunctival epithelium in vitro].

PURPOSES: To detect the best method of culture and preservation of human conjunctival epithelia. METHODS: Human conjunctival epithelia were cultured by tissue inoculation, mechanical separation or enzyme digestion with 0.25% trypsin. The cultured cells were identified through their morphology, growing features and immunohistochemical staining. The third and fourth passage confluent cells were frozen in liquid nitrogen, and resuscitated 30 days later. RESULTS: Cells from tissue digested with 0.25% Trypsin grew much better than those from tissue inoculation. No cell outgrew in mechanical separating group. The cultured cells spread along the flask in polygonal shape and positive in pan-Keratin staining. Ninty percent of the cryopreserved cells were successfully resuscitated. CONCLUSION: Tissue digestion with trypsin is the best approach to culture human conjunctival epithelium, and the cultured cells can be cryopreserved in liquid nitrogen.

Cell Culture Techniques↗

PubMed1999

Effects of dark-rearing on triphenyl phosphate-induced neuropathy in the visual system of the developing European ferret (Mustela putorius furo).

Results of a previous study in our lab (Tanaka et al., 1994) suggested that the onset of susceptibility to the organophosphorus compound triphenyl phosphite (TPP) in the developing ferret visual system might be closely related to eye opening and the onset of light stimulation. In order to explore this idea further, TPP was administered to ferret kits that had been raised for varying periods of time in total darkness to assess whether a delay in the onset of light stimulation to the visual system might also result in a delay in its susceptibility to TPP. Ferret kits were raised from birth either in total darkness or in open-sided sheds exposed to ambient light, injected subcutaneously with TPP (888 mg/kg body weight) at 5.5, 7.5, 9.5, or 21.5 wk of age, euthanized, and perfused transcardially with a 10% formalin-saline solution 4 d after injection. Brains were sectioned parasagittally at a thickness of 40 microm and subsequently processed with the Fink-Heimer silver impregnation technique to reveal the presence of degenerating axons and terminals, and with cresyl violet stain to delineate nuclear boundaries and cell soma morphology. Comparisons among degeneration patterns present in light-reared and dark-reared kits at the four ages examined revealed that the time of onset, extent, and density of TPP-induced axonal and terminal degeneration seen in the lateral geniculate nucleus and primary visual cortex did not differ significantly between light- and dark-reared groups, with the possible exception of dark-reared kits exposed to TPP at 7.5 wk of age. In addition, neurons in the primary visual cortex showed shrinkage and increased packing densities in kits exposed to TPP in both light and dark environments, as well as in dark-reared non-injected kits. The results of this study indicate that dark-rearing does not delay the onset or lessen the severity of TPP-induced axonal and terminal degeneration in the developing visual system of the ferret. Data suggest that light activation and stimulation of the retino-geniculo-striatal visual pathway is not a necessary prerequisite for the onset of visual system susceptibility to the axonopathic effects of triphenyl phosphite.

Animals↗

PubMed1999

Australia's notifiable diseases status, 1998. Annual report of the National Notifiable Diseases Surveillance System.

In 1998 there were 85,096 notifications to the National Notifiable Diseases Surveillance System; slightly lower than in 1997 (89,579). The number of measles cases remained low, and well below the number reported in the outbreak years of 1993 and 1994. Rubella notifications further decreased and remained low in 1998. The Measles Control Campaign from August to November 1998, did not impact significantly on the number of measles or rubella cases reported for 1998. Notifications of Haemophilus influenzae type b reached a record low since surveillance began in 1991, and appeared to have stabilised at a low rate since the introduction of the conjugated vaccine in 1992. The previously reported outbreak of pertussis in 1997 tapered off in early 1998. Food-borne disease, or detection of disease, appeared to be on the rise with an increase in notification rates of campylobacteriosis and salmonellosis. Notifications of hepatitis A decreased, correcting the previous high number of notifications in 1997. Sexually transmissible diseases (STDs) increased. Notifications for chlamydial infection were the highest for all sexually transmitted diseases and third highest for all notifiable diseases. Notifications of gonococcal infection also continued to rise and have doubled since 1991, whilst notifications for syphilis increased slightly after falling steadily over recent years. Arbovirus infections of concern in 1998 were dengue outbreaks in Far North Queensland and the first case of Japanese Encephalitis for mainland Australia, highlighting the importance of surveillance of arboviruses and vectors for their detection and management.

Australia↗

PubMed1999

The molecular basis for the B(A) allele: an amino acid alteration in the human histoblood group B alpha-(1,3)-galactosyltransferase increases its intrinsic alpha-(1,3)-N-acetylgalactosaminyltransferase activity.

The formation of the subgroup B(A) phenotype is thought to be due to an overlapping specificity of the human blood group A and B transferases. A new molecular basis for the B(A) allele, resulting from the C(700) to G substitution which predicts the alteration of Pro(234) to Ala, just ahead of the second of the four amino acid residues which differentiates the specificities of the A and B transferases, is reported here. Compared to normal group B sera, a relatively lower B-transferase activity was demonstrated in the B(A) serum, which correlated well with the observation of a smaller amount of B antigen on the B(A) red cells. Also a much higher A-transferase activity was demonstrated in the B(A) serum in contrast to the minute amount of A-transferase activity found in normal group B sera. The formation of the B(A) phenotype in this report is most likely due to the shifting of the specificity of the B transferase rather than an enhanced B-transferase activity which was previously presumed to be responsible for the formation of this phenotype. The Pro(234) to Ala alteration is suggested to be responsible for the shifting of the specificity with a subsequent increase in A- but a decrease in B-transferase activity. This new B(A) allele shows that not only the four critical residues but also the neighboring areas may influence the specificity of the A and B transferases.

ABO Blood-Group System↗

PubMed1999

Proteolytic processing of big endothelin-3 by the kell blood group protein.

Kell blood group protein shares a consensus sequence (H.E.X.X.H) with a large family of zinc-dependent endopeptidases. Kell has closest homology with neutral endopeptidase 24.11, endothelin converting enzyme-1 (ECE-1), and the PEX gene product that, as a group, comprise the M13 subfamily of mammalian neutral endopeptidases. The proteolytic activity of the M13 members, but not of Kell, has been previously demonstrated. A secreted form of wild-type Kell protein (s-Kell), devoid of the intracellular and transmembrane domains, was expressed in sf9 cells. As a negative control, an inactive mutant Kell protein (E582G) was expressed. As determined by N-terminal amino acid sequencing and mass spectrometry of the cleaved products, wild-type s-Kell, but not the control mutant protein, specifically cleaved big endothelin-3 (ET-3) at Trp(21)-Ile(22), yielding ET-3, and, to a much lesser extent, also cleaved big ET-1 and big ET-2 at Trp(21)-Val(22), yielding ET-1 and ET-2. Enzymatic activity was partially inhibited by phosphoramidon. s-Kell has an acidic pH optimum (pH 6.0 to 6.5). Like the recombinant protein, red blood cells of common Kell phenotype also preferentially process big ET-3, in contrast to Ko (null) cells that do not. These data demonstrate that the Kell blood group protein is a proteolytic enzyme that processes big ET-3, generating ET-3, a potent bioactive peptide with multiple biological roles.

Endothelin-3↗

PubMed1999

Long QT syndrome-associated mutations in the S4-S5 linker of KvLQT1 potassium channels modify gating and interaction with minK subunits.

Long QT syndrome is an inherited disorder of cardiac repolarization caused by mutations in cardiac ion channel genes, including KVLQT1. In this study, the functional consequences of three long QT-associated missense mutations in KvLQT1 (R243C, W248R, E261K) were characterized using the Xenopus oocyte heterologous expression system and two-microelectrode voltage clamp techniques. These mutations are located in or near the intracellular linker between the S4 and S5 transmembrane domains, a region implicated in activation gating of potassium channels. The E261K mutation caused loss of function and did not interact with wild-type KvLQT1 subunits. R243C or W248R KvLQT1 subunits formed functional channels, but compared with wild-type KvLQT1 current, the rate of activation was slower, and the voltage dependence of activation and inactivation was shifted to more positive potentials. Co expression of minK and KvLQT1 channel subunits induces a slow delayed rectifier K(+) current, I(Ks), characterized by slow activation and a markedly increased magnitude compared with current induced by KvLQT1 subunits alone. Coexpression of minK with R243C or W248R KvLQT1 subunits suppressed current, suggesting that coassembly of mutant subunits with minK prevented normal channel gating. The decrease in I(Ks) caused by loss of function or altered gating properties explains the prolonged QT interval and increased risk of arrhythmia and sudden death associated with these mutations in KVLQT1.

Animals↗

PubMed1999

Targeted correction of an episomal gene in mammalian cells by a short DNA fragment tethered to a triplex-forming oligonucleotide.

Triplex-forming oligonucleotides (TFOs) can bind to polypurine/polypyrimidine regions in DNA in a sequence-specific manner and provoke DNA repair. We have coupled a TFO to a short donor fragment of DNA that shares homology to a selected gene as a strategy to mediate gene targeting and correction. In this bifunctional oligonucleotide, the TFO domain is designed to bind the target gene and stimulate repair and recombination, with the donor domain positioned for recombination and information transfer. A series of these tethered donor-TFO (TD-TFO) molecules with donor domains of 40-44 nucleotides and TFO domains in both the purine and pyrimidine triplex motifs were tested for their ability to mediate either gene correction or mutation of a supF reporter gene contained in a SV40 shuttle vector in mammalian cells. In vitro binding assays revealed that the attachment of the donor domain via a flexible linker did not significantly alter the binding affinity of the TFO domain for the polypurine site in the supF target DNA, with equilibrium dissociation constants in the 10(-8) M range. Experiments in which the target vector and the linked TD-TFOs were pre-incubated in vitro and co-transfected into cells led to conversion frequencies approaching 1%, 4-fold greater than with the two domains unlinked. When cells that had been previously transfected with the SV40 vector were electroporated with the TD-TFOs, frequencies of base pair-specific gene correction were seen in the range of 0.04%, up to 50-fold over background and at least 3-fold over either domain alone or in unlinked combinations. Sequence conversion by the TD-TFOs was achieved using either single- or double-stranded donor domains and either triplex motif. Substitution of either domain in the TD-TFO with control sequences yielded reagents with diminished activity, as did mixtures of unlinked TFO and donor DNA segments. The boost in activity provided by the attached TFO domain was reduced in cells deficient in the nucleotide excision repair factor XPA but was restored in a subclone of these cells expressing XPA cDNA, suggesting a role for nucleotide excision repair in the pathway of triple helix-stimulated gene conversion. The ability to correct or mutate a specific target site in mammalian cells using the TD-TFO strategy may provide a useful tool for research and possibly for therapeutic applications.

Animals↗

PubMed1999

ebi regulates epidermal growth factor receptor signaling pathways in Drosophila.

ebi regulates the epidermal growth factor receptor (EGFR) signaling pathway at multiple steps in Drosophila development. Mutations in ebi and Egfr lead to similar phenotypes and show genetic interactions. However, ebi does not show genetic interactions with other RTKs (e.g., torso) or with components of the canonical Ras/MAP kinase pathway. ebi encodes an evolutionarily conserved protein with a unique amino terminus, distantly related to F-box sequences, and six tandemly arranged carboxy-terminal WD40 repeats. The existence of closely related proteins in yeast, plants, and humans suggests that ebi functions in a highly conserved biochemical pathway. Proteins with related structures regulate protein degradation. Similarly, in the developing eye, ebi promotes EGFR-dependent down-regulation of Tramtrack88, an antagonist of neuronal development.

Amino Acid Sequence↗

PubMed1999

[Missense mutations of exons 14 and 18 of Wilson's disease gene in Chinese patients]

OBJECTIVE: To investigate the characteristics of mutations of exons 14 and 18 of Wilson's disease (WD) gene in Chinese patients. METHODS: The subjects of study included 60 unrelated normal controls and 44 unrelated WD patients. Genomic DNA was prepared from peripheral blood leukocytes by a salt-out method. Mutations of exons 14 and 18 in these subjects were screened by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and further confirmed by sequencing. RESULTS: One patient was homozygous for Arg1041Pro mutation of exon 14 and another patient was heterozygous for Asn1270Ser mutation of exon 18. CONCLUSION: The mutations of exons 14 and 18 of WD gene in Chinese patients were confirmed by sequencing for the first time in China. Arg1041Pro was identified as a novel missense mutation. In addition, an Asn1270Ser, previously described mutation, was detected in this study. But exons 14 and 18 are not the hot point mutations of WD gene in Chinese patients.

Journal Article↗

PubMed1999

Mitochondrial tRNA(leu)(UUR) gene mutation and the decreased activity of cytochrome c oxidase in preeclampsia.

To explore the roles of mitochondria tRNA(leu)(UUR) gene mutation at nucleotide 3243 and the activity of cytochrome c oxidase in pathogenesis of preeclampsia, 57 patients with preeclampsia and 60 normotension pregnancy women were screened for tRNA(leu)(UUR) nt3243 A-->G mutation with the method of polymers chain reaction (PCR) and restriction fragment length polymorphism. Cytochrome c oxidase activity was determined by measuring the rate of cyanide-sensitive oxidation of reduced cytochrome c using luminosity photographer. The results showed that cytochrome c oxidase activity was significantly lower in the preeclampsia group (0.30 +/- 0.39/min, n = 32) than that in the controls (0.73 +/- 0.54/min, n = 26, P < 0.01). The mitochondria DNA mutation at position 3243 was not found in our series. The results suggested that the decreased activity of cytochrome c oxidase might impair the energy production, leading to the mitochondria dysfunction and placenta dysfunction in preeclampsia patients. Mitochondria dysfunction may be involved in the pathogenesis of preeclampsia. The mutation of mitochondria DNA may not be the common contributor of preeclampsia in our series.

Adult↗

PubMed1999

Long-term observation on the changes of somatotopy in the facial nucleus after nerve suture in the cat: morphological studies using retrograde labeling.

To examine the time course of plasticity of the cranial nucleus during axonal regeneration, we followed the topographical reorganization of the cat facial nucleus (FN) up to 24 months after facio-facial nerve suture using retrograde labeling methods. The trunk of the temporal-zygomatico-orbital and both superior and inferior buccolabial branches (defined as main branch) of the facial nerve was cut and sutured again under ketamine hydrochloride anesthesia. At 11-722 days after nerve suture, Fast Blue (FB) and 1,1'-dioctadecyl-3, 3, 3', 3'-tetramethylindocarbocyanine perchlorate (Dil) or horseradish peroxidase (HRP) were injected into the distal part of the sutured main branch and the unoperated posterior auricular branch, respectively. Until about 3 months after suture, the topographical pattern in FN was similar to that observed in normal cats. At about 4 months after suture, FB-labeled motoneurons were distributed not only in the lateral part (including intermediate, dorsal and ventrolateral divisions) but also in the medial subdivision of FN. After a survival period of 18-24 months, FB-labeled neurons were found all over the FN, and their number increased significantly. Interestingly, in the longer survival cases, we noticed that the Dil- or HRP-labeled posterior auricular branch motoneurons also showed a tendency to distribute outside the medial region. The present study showed that somatotopic disorganization starts at around 4 months after suture, which seems to be somewhat slower than that in rats, and continues until a much later postoperative period. Furthermore, we suggested a possibility that the regeneration of one branch may affect the somatotopy of the unoperated nerve branch. These phenomena may contribute to aberrant facial nerve functions such as abnormal associated movement and facial spasm observed after nerve injury.

Amidines↗