Search PubMed⌕ Search

Biomedical subjects

Z Lin

Publications and source records attributed to Z Lin.

At least 235 records · Page 13Linked to original sources
PubMed1997

Identification of functionally distinct isoforms of the N-type Ca2+ channel in rat sympathetic ganglia and brain.

The N channel is critical for regulating release of neurotransmitter at many synapses, and even subtle differences in its activity would be expected to influence the efficacy of synaptic transmission. Although several splice variants of the N channel are expressed in the mammalian nervous system, their biological importance is presently unclear. Here, we show that variants of the alpha1B subunit of the N channel are expressed in sympathetic ganglia and that alternative splicing within IIIS3-S4 and IVS3-S4 generate kinetically distinct channels. We further show a striking difference between the expression pattern of the S3-S4 variants in brain and peripheral ganglia and conclude that the brain-dominant form of the N channel gates 2-to-4-fold more rapidly than that predominant in ganglia.

Alternative Splicing↗
PubMed1997

Fas ligand expression in islets of Langerhans does not confer immune privilege and instead targets them for rapid destruction.

Fas ligand is believed to mediate immune privilege in a variety of tissues, including the eye, testis, and a subset of tumors. We tested whether expression of Fas ligand on pancreatic islets either following adenoviral or germline gene transfer could confer immune privilege after transplantation. Islets were infected with an adenoviral vector containing the murine Fas ligand cDNA (AdFasL), and were transplanted into allogenic diabetic hosts. Paradoxically, AdFasL-infected islets underwent accelerated neutrophilic rejection. The rejection was T cell and B cell independent and required Fas protein expression by host cells, but not on islets. Similarly, transgenic mice expressing Fas ligand in pancreatic beta cells developed massive neutrophilic infiltrates and diabetes at a young age. Thus, Fas ligand expression on pancreatic islets results in neutrophilic infiltration and islet destruction. These results have important implications for the development of Fas ligand-based immunotherapies.

Adenoviridae↗
PubMed1997

The effect of intravenous vasopressin on gastric myoelectrical activity in human subjects.

UNLABELLED: Vasopressin's role in the sensation of nausea is incompletely understood. In this study, our goals were to investigate whether high intravenous vasopressin levels in normal subjects would induce nausea and vomiting and to determine the electrogastrographic (EGG) pattern which would develop at these concentrations. METHODS: EGG recordings were made on five fasting healthy subjects (three females, mean age: 27 years). Vasopressin was infused (0.15 or 0.3 U kg-1 h-1) for 1 h after a 30-min baseline recording. Serum vasopressin levels were measured every 15 min. Symptoms of nausea, cramping, retching, vomiting and bloating were graded from 0 to 5 (0 = none, 5 = most severe). Normal saline at the same rate was then infused for 1 h, with recording of symptoms and measuring blood levels of vasopressin as done previously. RESULTS: EGG data showed a 43% reduction in the percentage of normal slow waves (96-53%) at a vasopressin rate of 0.3 U kg-1 h-1. A 29% reduction (88-59%) occurred at 0.15 U kg-1 h-1. The EGG dominant frequency decreased by 0.8 cpm (3.07-2.25) for the high dose, while only 0.2 cpm reduction (2.9-2.7) occurred at the lower dose. Bradygastria (< 2.4 cpm) rather than tachygastria (> 3.7 cpm) was the predominant abnormality with the high dose. Symptoms of nausea correlated with the infusion of vasopressin and significantly increased with the higher dose. CONCLUSIONS: (i) At supraphysiological vasopressin levels, nausea was present in 80% of subjects but there was no retching or vomiting, (ii) bradygastria was the predominant dysrhythmia at these high vasopressin concentrations, (iii) increasing vasopressin levels correlated symptomatically with increases in nausea.

Adult↗
PubMed1997

A new nausea model in humans produces mild nausea without electrogastrogram and vasopressin changes.

UNLABELLED: The standard human vection model utilized for nausea has been an optokinetic drum. This model may be difficult to extrapolate to the usual clinical setting. Our goals were to develop an experimental model which could induce low grade nausea in humans and to determine the relationship between mild nausea and changes in the electrogastrogram and plasma vasopressin concentrations. METHODS: Twenty-one volunteers (11 males, mean age: 37 years) participated. At baseline and throughout the study the electrogastrogram was monitored, blood was drawn for vasopressin assay and symptoms of nausea, dizziness and headache were rated on a 0-10-point scale. Subjects were semireclined in a darkened room while viewing moving bars of light rotating at a rate of 85 degrees s-1. Subjects were asked to rate their proneness to motion sickness and their current level of anxiety at baseline. RESULTS: Eight subjects developed mild to moderate (mean: 3.6) nausea during vection. Symptoms of nausea were correlated with a reported history of motion sickness (r = 0.49, P < 0.05) but not with anxiety (r = 0.14, P = 0.54). Degrees of nausea correlated with degrees of dizziness (r = 0.47, P < 0.05) but not with headache (r = 0.29, P = 0.14). Subjects who developed mild nausea were not significantly more likely to exhibit altered electrogastrogram or vasopressin than subjects who did not report nausea. Vasopressin levels during baseline and experimental conditions were highly correlated (r = 0.66, P < 0.005 and r = 0.55 P < 0.005, respectively) with reported baseline anxiety. CONCLUSIONS: (1) This new model in humans induced mild nausea that was unrelated to electrogastrogram and vasopressin abnormalities, (2) high correlation between anxiety and vasopressin suggests that vasopressin may not be directly related to nausea, and (3) these data indicate that onset of nausea mediated centrally can occur without associated electrogastrogram changes.

Adult↗
PubMed1997

A model of the lutropin/choriogonadotropin receptor: insights into the structural and functional effects of constitutively activating mutations.

A model of the seven transmembrane helical domain (7-TM) of the human lutropin receptor was constructed from the 2D electron density map of bovine rhodopsin and a set of geometric parameters derived from a published analysis of 204 G-protein coupled receptor sequences. The Self-Consistent Ensemble Optimization method was applied to predict overall side chain packing. The model is consistent with the general helical packing properties expected of transmembrane proteins and suggests possible structural and functional effects of constitutively activating mutations. A tightly packed hydrophobic cluster formed between the intracellular halves of TM5 and TM6, as well as a specific H-bonding network formed between the central regions of TM6 and TM7, is proposed to be critical for stabilizing the inactive form of the receptor. The model suggests that single activating mutations perturb the specific interactions of TM6 with TM5 and TM7, either by disrupting the hydrophobic packing between TM5 and TM6, or by weakening the H-bonds between TM6 and TM7.

Amino Acid Sequence↗
PubMed1997

[Isolation of verotoxin-producing Escherichia coli from cattle and characterization of the isolated strains].

Attempts to isolate Verotoxin-producing Escherichia coli (VTEC) from 53 dead baby cattle were made during a period from January 1989 to July 1991. From 6 cattle of 5 farms, VTECs were isolated. Further examination of cattle from 2 farms with dead baby cattle and from 1 farm with an outbreak of diarrhea among baby cattle, from 8 of 26 cattle with diarrhea and from 9 of 58 healthy cattle, VTECs were isolated. Several serotypes which caused food poisoning in Japan as well as in the US and Europe were included in the isolated strains. VTECs were also isolated from several cattle imported from the US suggesting that these VTECs were from outside the country together with the imported cattle.

Animals↗
PubMed1997

[Alterations in metastatic properties of hepatocellular carcinoma cell following H-ras oncogene transfection].

OBJECTIVE: To demonstrate the relationship between H-ras oncogene and HCC metastasis. METHODS: Activated H-ras oncogenes were transfected into SMMC7721, a cell line derived from human hepatocellular carcinoma (HCC), by calcium phosphate transfection method. Some metastasis-related parameters were detected in vitro, including adhesion assay, migration assay, expresion of collagenase IV (cIVase) and EGFR. RESULTS: The abilities of H-ras-transfected cell clones in adhesion to laminin or fibronectin, migration, cIVase secretion increased markedly, and the expression of EGFR elerated moderately. More importantly, these alterations were consistently positive with the expression of p21, the protein product of H-ras oncogene. CONCLUSION: H-ras oncogene could induce the metastatic phenotype of HCC cell in vitro, therefore enhancing its metastatic potential.

Carcinoma, Hepatocellular↗
PubMed1997

[Long-term results of intravesical N-CWS instillation to prevent recurrence after surgery for bladder cancer].

OBJECTIVE: To evaluate the long term results of intravesical nocardia rubre cell wall skeleton instillation to prevent recurrence after surgery for bladder cancer. METHODS: A randomized and placedo-controlled trial on intravesical N-CWS instillation versus mitomycin-C(MMC) therapy for recurrence prevention in postopenative bladder cancer patients was carried out. RESULTS: Fourty-five patients were treated with N-CWS with 39 followed for 12 to 60 months. Thirteen patients developed recurrence. The 1-year tumor free survival rate was 87.2% and that at 5 years was 66.7%. Thirty patients as treated with MMC serving as controll with 25 followed for the same duration, twelve patients developed recurrence. The 1-year tumor free survival rate was 84% and that at 5 years was 52%. The results indicate that N-CWS gave better results with rare and milder side effects. CONCLUSION: N-CWS is believed to be one of the effective drugs in preventing bladder cancer recurrence after surgery.

Adjuvants, Immunologic↗
PubMed1997

[Inhibition of in vivo growth of lung carcinoma cells after transfection with gap junction gene Cx43].

OBJECTIVE: To explore the effects of expression of gap junction gene and cell-cell communication on tumor growth. METHODS: A highly metastatic human lung carcinoma cell line PG was used. PG cells were defective of gap junctional intercellular communication(GJIC) and lacking expression of gap junction gene Cx43. By transfection, Cx43 cDNA was introduced into PG cells and blank vector cDNA was used as mock control. By using Northern-blot, dye-transfer methods and examinations of in vitro/in vivo growth, stable Cx43 transfectant cells were studied. RESULTS: The mock control cells resembled untransfected PG cells in lacking expression of Cx43 and GJIC function. They grew fast in soft agar(colony formation rate 11.6%) and in nude mice (average tumor weight 3.47 g in 28 days). The Cx43 transfectant cells showed increased level of Cx43 mRNA and increased function of GJIC. Cell growth in soft agar and in nude mice was markedly retarded. The inhibition rate was 90% and 75%, respectively. CONCLUSION: Increased expression of gap junction gene Cx43 induced tumor-suppressing effects in human lung carcinoma cells.

Animals↗
PubMed1997

Non-trans-scleral suture fixation of posterior chamber intraocular lenses in the absence of posterior capsular support.

PURPOSE: To develop a new technique for fixation of posterior chamber intraocular lens (IOL) in the absence of posterior capsule support. MATERIALS AND METHODS: We performed non-trans-scleral fixation of intraocular lenses on 24 cases (24 eyes) without posterior capsule support. Two scleral flaps with limbal incisions and two peripheral iridectomies were made at 1 o'clock and 7 o'clock positions respectively. A suture-leading needle was used to lead the prolene suture from the limbal incision and iridectomy on one side through the iridectomy and limbal incision on the other side. Intraocular lens (IOL) was then fixed in the ciliary sulcus. RESULTS: After a mean follow-up of 6.6 months (range from 3 to 14 months), corrected visual acuity of 16 cases (16 eyes, 66.7%) got 0.5 or better. Postoperative complications included discoria (4 eyes), surface membrane formation (1 eye), choroidal detachment (1 eye) and tilt of IOL (1 eyes), but all were not severe. CONCLUSION: In some situations such as low intraocular pressure, non-penetration scleral fixation may be a good way to implant IOL in the absence of posterior capsule support.

Adolescent↗
PubMed1997

[Preparation of liposomes of superoxide dismutase].

The liposomes of SOD were prepared by reverse-phase evaporation. By examining the important effects on preparation we obtained the liposomes of SOD. The encapsulation of SOD was more than 60%, and the stability of the liposomes was excellent.

Delayed-Action Preparations↗
PubMed1997

Study on small hepatocellular carcinoma and its extension.

This paper summarizes the "study on small hepatocellular carcinoma and its extension" in Liver Cancer Institute, Zhongshan Hospital of Shanghai Medical University during the past 25 years. The results indicated that it was an important approach to obtain long-term HCC survivors, of the 239 patients with 5-year survival, small HCC resection accounted for 51.4%. It was an effective approach to improve the prognosis of HCC in the entire series, the 5-year survival of inpatients treated in authors' institution was 4.8% in 1958-1970, 12.2% in 1971-1983, and 46.7% in 1984-1995; which were correlated to the increase proportion of small HCC resection in the series; it was more effective as compared to large HCC resection, the 5 year survival was 61.3% (n = 645) versus 33.6% (n = 950). Extensions of small HCC study included early detection and treatment of small recurrent HCC, of the 147 patients with re-resection, the 5-year survival was 48.9% calculated from the time of first resection. Another extension was conversion of large HCC into small HCC, using multimodality combination treatment, 72 out of the 663 patients with surgically verified unresectable HCCs have been converted to resectable, 5-year survival being 62.1%, which was comparable to that of small HCC resection. Studies on related basic aspect of small HCC such as cell origin of recurrence, and molecular aspect of small HCC, indicated that biological characteristics, particularly the tumor invasiveness, remained the key link for further prolong survival after small HCC resection. Recently, a "patient-like" human HCC metastatic model in nude mice has been established. Experimental interventions have also been tried. Clinical trials for prevention of recurrence after small HCC resection have shown preliminary encouraging results. However, the "cost-effectiveness" of screening, the invasiveness of HCC, the multicentric origin, the coexisted Child C cirrhosis, etc., remained great challenge.

Animals↗
PubMed1997

[Cord blood plasma selectively stimulates the expansion of hematopoietic pregenitor cells in vitro].

OBJECTIVE: To explore the effect of cord blood (CB) plasma on the expansion of hematopoietic progenitor cells. METHODS: The effect of CB plasma on the expansion of CB and bone marrow (BM)-derived hematopoietic progenitor cells was studies and compared with those of adult's peripheral blood (PB) plasma and cytokines such as IL-3 and SCF. RESULTS: (1) CB plasma increased CFU yields of CB-derived progenitor cells by 2.23 +/- 0.52-fold and this expansion was dependent on CB plasma concentrations supplemented in the cultures. Greater expansion of progenitor cells was found when ABO was unmatched between the CB-derived cells and CB plasma. (2) Stimulating effect of CB plasma on BM-derived progenitor cells was also related to ABO type. CFU yields were increased by 1.55 +/- 0.43-fold when ABO was unmatched and not increased when ABO was matched. (3) Expansion of CB-derived progenitor cells by IL-3 and SCF was revealed. Significant increase in CFU yields occurred in the addition of both the cytokine and the CB plasma. (4) No expansion occurred in CB-and BM-derived cell cultures supplemented with PB plasma. CONCLUSION: There is factor(s) selectively stimulating expansion of progenitor cells in CB plasma. It may be beneficial that CB plasma was transfused with CB-derived stem cell transplantation.

Animals↗
PubMed1997

[Study on the immunophenotype of myeloid cells in myelodysplastic syndromes and its clinical implications].

OBJECTIVE: To explore the immunophenotype of myeloid cells in myelodysplastic syndromes and its clinical implications. METHODS: A panel of monoclonal antibodies was used to detect CD13, CD33, CD15 and CD14 on the membrane surfaces of myeloid cells in the bone marrow from 51 patients with myelodysplastic syndromes (MDS), 21 with aplastic anemia (AA), 21 with paroxysmal nocturnal hemoglobinuria (PNH), and 15 normal subjects, by immunoenzymatic assay. The morphology and chromosome karyotype of bone marrow cells of MDS patients were also examined. RESULTS: CD14+ cells, CD13+ cells and CD33+ cells in the bone marrow were more in MDS patients than in normal controls, AA patients and PNH patients. CD15+ cells in the bone marrow were less in MDS patients than in normal controls. The percentages of CD14, CD13 and CD33 positive cells in the bone marrow of MDS patients were related to the percentage of myeloblast, the chromosomal aberrations and the response to treatment. CONCLUSION: There was an immunophenotypic misexpression of myeloid cells in MDS patients. Immunophenotype analysis of myeloid cells might be useful for the diagnosis and directing treatment in MDS patients.

Adolescent↗
PubMed1997

Median arcuate ligament syndrome: a possible cause of idiopathic gastroparesis.

The median arcuate ligament syndrome (MALS) is characterized by abdominal pain, nausea, and vomiting attributed to compression of the celiac axis by a fibrous band (the median arcuate ligament) connecting the diaphragmatic crura. The pathophysiologic origin of these symptoms is not clearly understood. Theories invoking either a neurogenic or vascular origin for the clinical features associated with MALS have been proposed, but objective evidence to support these theories is lacking. We describe the clinical course and gastric myoelectrical features of a patient with postprandial epigastric pain, weight loss, gastroparesis, and gastric dysrhythmias in whom a diagnosis of MALS was established. Surgical decompression of the celiac axis in our patient resulted in resolution of abdominal pain, return to a full diet within 4 weeks without nausea or vomiting, improvement in radionuclide gastric emptying, and restoration of the gastric electrical rhythm to a normal 3 cycle/min conduction rate. This is the first demonstration of altered gastric myoelectrical activity in a patient with MALS. The regularization of the gastric electrical rhythm in our patient after surgical decompression of the celiac axis would support a neurogenic basis for the symptoms associated with MALS. MALS should be excluded in patients with idiopathic gastroparesis and unexplained epigastric pain.

Abdominal Pain↗