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Biomedical subjects

S H Lin

Publications and source records attributed to S H Lin.

At least 109 records · Page 6Linked to original sources
PubMed1998

Isolation and characterization of PAGE-1 and GAGE-7. New genes expressed in the LNCaP prostate cancer progression model that share homology with melanoma-associated antigens.

The LNCaP progression model of human prostate cancer consists of lineage-related sublines that differ in their androgen sensitivity and metastatic potential. A differential display polymerase chain reaction was employed to evaluate mRNA expression differences between the LNCaP sublines in order to define the differences in gene expression between the androgen-sensitive, nontumorigenic LNCaP cell line and the androgen-insensitive, metastatic LNCaP sublines, C4-2 and C4-2B. An amplicon, BG16.21, was isolated that showed increased expression in the androgen-independent and metastatic LNCaP sublines, C4-2 and C4-2B. Hybridization screening of a lambda gt11 expression library with BG16.21 revealed two transcripts, both homologous to BG16.21 at the 3' end. A GenBankTM data base search using the GCG Wisconsin software package revealed the shorter approximately 600-bp transcript (designated GAGE-7) to be a new member of the GAGE family. The second approximately 700-bp transcript was a novel gene (designated PAGE-1, "prostate associated gene") with only 45% homology to GAGE gene family members. RNA blot analysis demonstrated that GAGE-7 mRNA was expressed at equal levels in all lineage related prostate cancer cell sublines, while PAGE-1 mRNA levels were elevated 5-fold in C4-2 and C4-2B as compared with LNCaP cells. Neither GAGE-7 nor PAGE-1 demonstrated any regulation by androgens in the prostate cancer cell lines used in this study. PAGE-1 and GAGE-7 expression was found to be restricted to testes (high) and placenta (low) on human multiple tissue Northern blots. As GAGE/MAGE antigens were reported previously to be targets for tumor-specific cytotoxic lymphocytes in melanoma, these results suggest that PAGE-1 and GAGE-7 may be related to prostate cancer progression and may serve as potential targets for novel therapies.

Amino Acid Sequence↗
PubMed1998

Disassociation of sigma subunit from RNA polymerase of Xanthomonas oryzae pv. oryzae by phage Xp10 infection.

The sigma subunit of Xanthomonas oryzae pv. oryzae is disassociated from host RNA polymerase after phage Xp10 infection. To clarify the possible mechanism for this observation, sigma subunit was purified and an antiserum against sigma subunit was prepared. Immunoprecipitation of RNA polymerase by the anti-core RNA polymerase antiserum, followed by immunoblotting with anti-sigma subunit antibody, revealed that sigma subunit was lost from RNA polymerase within 10 minutes after Xp10 infection. Loss of sigma subunit was not observed under other stress conditions including heat and cold stress, starvation and growth to stationary phase. Two-dimensional immunoblotting analysis did not reveal any covalent modification of either sigma subunit or RNA polymerase after Xp10 infection. These results suggest that separation of th subunit from RNA polymerase may be due to competition with other binding factors.

Antibodies, Bacterial↗
PubMed1998

Demonstration of adhesion activity of the soluble Ig-domain protein C-CAM4 by attachment to the plasma membrane.

The carcinoembryonic antigen (CEA) family is a large group of proteins with immunoglobulin (Ig)-like structures. The membrane-associated CEA-family proteins have been shown to mediate intercellular adhesion. In addition to these membrane-associated proteins, several secreted CEA-like proteins, such as C-CAM4, PSG1b, and PSG11s, have also been identified. The functions of these soluble proteins are not clear because they cannot support intercellular adhesion like the membrane-associated proteins can. A fundamental question important for understanding the functions of these soluble proteins is whether they can interact in a homophilic fashion as do many of their membrane-associated homologues. We found that the homophilic interactions between these soluble proteins were too weak to be detected by solution binding assays. This is not unexpected because interactions between adhesion molecules are usually transient and weak to allow for control of association and dissociation. By expressing these soluble CEA-family proteins, C-CAM4, PSG1b, and PSG11s, as membrane-anchored forms, we showed that C-CAM4 could mediate intercellular adhesion, whereas PSG1b and PSG11s, despite their 52% identity to C-CAM4, could not. These results suggest that C-CAM4, but not PSG1b and PSG11s, can probably form homodimers. Thus, these secretory CEA-family members most likely have different interaction mechanisms, i.e., C-CAM4 might function as dimers, while PSGs might function as monomers.

Adenosine Triphosphatases↗
PubMed1998

Metabolic mapping of the brain in pregnant, parturient and lactating rats using fos immunohistochemistry.

The present study was designed to investigate Fos-positive neurons of the female rat brain at various reproductive states in order to analyze the metabolic map connected with pregnancy, parturition and lactation. The number of Fos-positive neurons in each brain nucleus was analyzed with a quantitative immunohistochemical method in virgin, pregnant, parturient, lactating and arrested lactating rats. In parturient rats, a significant number of Fos-positive neurons was observed as compared to virgin or pregnant females in the following brain regions; the bed nucleus of the stria terminalis (BST), lateral septal nucleus (LS), medial preoptic area (MPA), periventricular hypothalamic nucleus (Pe), parvocellular paraventricular hypothalamic nucleus (PaPVN), magnocellular paraventricular hypothalamic nucleus (MaPVN), supraoptic nucleus (SON), paraventricular thalamic nucleus (PV), anterior hypothalamic area (AHA), lateral hypothalamic area (LH), amygdaloid nucleus (AM), supramammillary nucleus (SuM), substantia nigra (SN), central grey (CG), microcellular tegmental nucleus (MiTg), subparafascicular thalamic nucleus (SPF), posterior hypothalamic area (PH), dorsal raphe nucleus (DR), locus coeruleus (LC), dorsal parabrachial nucleus (DPB), nucleus of solitary tract (Sol), and ventrolateral medulla (VLM). Significant differences were found in the number of Fos-positive neurons between parturient and lactating females, although localization of Fos-positive neurons in lactating females was quite similar to parturient ones. Between parturient and lactating rats: (1) In the MPA, PaPVN, AHA, arcuate hypothalamic nucleus (Arc), ventromedial hypothalamic nucleus (VMH), MLT, and Ge, the number of Fos-positive neurons of lactating females were significantly higher than those of parturient ones; (2) In the LS, Pe, PV, LH, AM, SuM, CG, MiTg, SPF, PH, DR, LC, and VLM, there was no significant differences in the number of Fos-positive neurons; (3) In the BST, MaPVN, SON, SN, DPB and Sol, the number of Fos-positive neurons of lactating rats were significantly lower than those of parturient ones. These different patterns of Fos expression among many brain regions may be owing to the functional differences in each region. Fos expression in lactating rats was apparently induced by suckling stimulation because the removal of their litters immediately after parturition completely eliminated expression of Fos protein in each nucleus. These results suggest that the localization of Fos-positive neurons in a number of neural populations throughout the brain may be revealing the neural circuits in response to parturition or lactation.

Animals↗
PubMed1998

Association of an 80 kDa protein with C-CAM1 cytoplasmic domain correlates with C-CAM1-mediated growth inhibition.

Decreased expression of C-CAM, a member of the CEA family of immunoglobulin like cell adhesion molecules, occurs in carcinomas of the colon, liver and prostate. Down regulation of C-CAM during the early stages of carcinogenesis in rat liver and human prostate has also been reported. We have recently shown that restoration of the expression of the isoform with long cytoplasmic domain, C-CAM1, leads to suppression of the tumorigenicity of prostatic carcinoma cells in vivo and growth suppression in vitro. These observations suggest that C-CAM1 may play an important role in regulating cell growth in normal tissues. Previous studies have demonstrated that the function of many members of the Ig-supergene family is dependent on interactions with cytoplasmic proteins. In the present study, we have used a bifunctional cross-linker to identify cellular proteins that interact directly with C-CAM1. Immunoblot analysis of WGA bound membrane proteins crosslinked with DSS identified a 180 kDa complex composed of C-CAM and an 80 kDa protein designated CAP-80 (C-CAM Associated Protein). Immunoprecipitation with anti-C-CAM antibodies showed that CAP-80 was co-precipitated with C-CAM from detergent solubilized, WGA-purified proteins. To assess the specificity of CAP-80 binding, the ability of CAP-80 to form stable complexes with C-CAM1 mutants expressed in insect cells was tested. Deletion of the cytoplasmic domain of C-CAM1 abolished complex formation whereas deletion of the extracellular Ig domains had no effect. These results suggest that a CAP-80 homologue (ICAP-80) is present in insect cells and ICAP-80 interacts with the cytoplasmic domain of C-CAM1. Replacement of Tyr488, a residue in the cytoplasmic domain known to be phosphorylated in vivo, with Phe did not diminish the association between C-CAM1 and ICAP-80, suggesting that Tyr488 phosphorylation is not required for association. The ability of various C-CAM1 mutants to associate with ICAP-80 correlated with their growth inhibitory activities, suggesting that ICAP-80/CAP-80 may play an important role in C-CAM1-mediated growth inhibition.

Adenosine Triphosphatases↗
PubMed1998

Dynamical principles in biological processes.

The purpose of this paper is to propose certain dynamical principles in biological systems, which can be used to explain the effectiveness of charge transfer or excitation transfer in biological systems. Some of these systems are accessible experimentally.

Electron Transport↗
PubMed1998

Evidence that endothelin-1 (ET-1) inhibits insulin-stimulated glucose uptake in rat adipocytes mainly through ETA receptors.

The specificity of endothelin (ET) receptors involved in the inhibition of insulin-stimulated glucose uptake (ISGU) in rat adipocytes was investigated. Adipocytes were isolated from the epididymal fat pads of Sprague-Dawley rats. To determine receptor subtypes, we used three ET isopeptides, ET-1 and ET-2, both of which are nonselective agonists, and ET-3, a selective agonist for ETC receptors, to displace [125I]ET-1 binding from the fat cells. The efficiency of displacement was ET-1 > ET-2 >> ET-3, indicating that the primary receptors involved belonged to the ETA subtype. At an equal concentration of 1 micromol/L, BQ-610, a selective ETA antagonist, displaced [125I]ET-1 from binding to fat cells, whereas IRL-1038, a selective ETB antagonist, did not. Using [3H]2-deoxy-D-1-glucose ([3H]2-DG) as a tracer in studies of glucose uptake, we found that equimolar BQ-610 completely reversed the inhibitory effect of ET-1 on ISGU, whereas IRL-1038 was ineffective. Northern blot analysis of adipocyte receptors showed abundant mRNA for ETA, but no ETB subtype. These results clearly demonstrate that ETA is the predominant receptor in rat adipocytes.

Adipocytes↗
PubMed1998

Comparison of the expression of two immediate early gene proteins, FosB and Fos in the rat preoptic area, hypothalamus and brainstem during pregnancy, parturition and lactation.

Medial preoptic area (MPA), supraoptic nucleus (SON), magnocellular (MaPVN) and parvocellular (PaPVN) paraventricular hypothalamic nuclei, and mesencephalic lateral tegmentum (MLT) are involved in maternal behavior, parturition and lactation. This study investigated the FosB and Fos immunoreactivity in these regions of virgin, pregnant, parturient, lactating, and lactating-arrested rats. The patterns of FosB and Fos expression were compared between the sections taken from the same animals. Quantitative immunohistochemistry revealed a significant increase in the numbers of FosB-positive neurons in the MPA, SON, MaPVN, and MLT of parturient and lactating females as compared with pregnant or virgin animals. In lactating rats, the numbers of FosB-positive neurons in the MPA, PaPVN, and MLT were increased, but the numbers in the SON and MaPVN were decreased as compared with parturient females. Many Fos-positive neurons were also seen in parturient and lactating rats, and the patterns of Fos expression in each region were quite similar to those of FosB. Moreover, double-labeling immunohistochemistry revealed that: (1) many FosB-positive nuclei were observed in oxytocin and vasopressin neurons of the SON and PVN in parturient rats; (2) within FosB-positive neurons, 89.5% in the MPA, 86.8% in the MLT of parturient rats, and 92% in the MPA and 90.8% in the MLT of lactating animals were also Fos-positive. Only a small number of FosB and Fos-positive neurons were seen in females that were killed in the early stage of parturition. Removal of the litters immediately after parturition completely eliminated FosB and Fos expression in each region in the dams. Taken together, the present results suggest that FosB expression is co-involved with Fos in the neural activation during parturition and lactation in rats.

Animals↗
PubMed1998

Physiological disposal of the potential alkali load in diet of the rat: steps to achieve acid-base balance.

The purpose of this study was to provide a better understanding of the physiological role of endogenous net organic acid production in rats consuming their usual diet. Balance studies were performed over 24 h, and urine was collected in the day and night portions of the diurnal cycle. A supplemented low-electrolyte diet(LED) was fed to determine whether urinary organic anions were identical to those in the diet. A titration procedure was developed to determine the pK of titratable groups in the urine of rats studied with and without an acid load. Although normal rats excreted net acid (NAE), the latter was inversely related to the amount of food consumed. The rates of excretion of bicarbonate (HCO3), citrate, unmeasured organic anions, and NH+4 were higher in the night portion of the diurnal cycle. NAE rose dramatically when alkali intake was decreased by consuming the LED. Dietary and urinary organic anions were not identical because rats fed the LED supplemented with potassium citrate excreted <10% of this alkali load as citrate and <25% as HCO3. In the 24 h after 3,000 ¿mol NH4Cl was given intraperitoneally, H+ did not appear to be retained, yet NAE rose by only close to 2,000 ¿eq. The rate of excretion of titratable groups with a pK in the 3 to 5 pH range fell by close to 1,000 ¿eq; most of these changes occurred in the first 7 h after NH4Cl was given. We conclude that rat chow provides a large net alkali load. There appear to be two types of endogenous acid production, a form associated with a rise in NAE (e.g., sulfuric acid) and dietary alkali-driven endogenous net acid production, which titrates this alkali. Renal excretion of organic anions makes these acids end products of metabolism.

Acid-Base Equilibrium↗
PubMed1998

The neuromuscular effects of mivacurium in adults with priming technique during nitrous oxide-fentanyl anesthesia: a randomized comparative study with succinylcholine.

BACKGROUND: We investigated the neuromuscular effects of equipotent dose (3 x ED90) of mivacurium either given as a single bolus or under the influence of priming technique, comparing with that of succinylcholine in adults undergoing elective surgery during nitrous oxide-narcotic anesthesia. METHODS: Sixty ASA class I patients of either sex with age between 16 to 49 years were randomly assigned to 3 groups for a trial of mivacurium under nitrous oxide-narcotic anesthesia. Group I (non-priming group, n = 20) received mivacurium 0.25 mg/kg straight as a single intubating dose; Group II (priming group, n = 20) received an intubating dose of 0.225 mg/kg mivacurium which was preceded by 0.025 mg/kg 3 min earlier; and Group III received an intubating bolus of succinylcholine 1 mg/kg. Thenar electromyogram response to supramaximal train-of-four stimulation of the ulnar nerve at 12-s intervals was used to determine neuromuscular blockade. Blood pressure and heart rate were recorded before and at 1-min interval for 3 min after injection of drugs. Data were presented as mean +/- standard deviation. P value < 0.05 was considered statistically significant. RESULTS: The onset time of mivacurium was accelerated by priming procedure in comparison with the nonpriming technique (2.0 min vs. 2.7 min), but it was much slower than that of succinylcholine (0.8 min). The priming procedure did not influence the duration of action or recovery. Side effects of mivacurium, such as cutaneous flushing and hypotension, were minimal at this dose in our patients. CONCLUSIONS: Priming technique (with 10% of the total dose as the priming dose, and 3 min as the priming interval) can hasten the onset of mivacurium in adults during nitrous oxide-narcotic anesthesia without influencing the duration of action and recovery time.

Adolescent↗
PubMed1998

Anesthetic management of a parturient with Eisenmenger's syndrome and preeclampsia during cesarean section--a case report.

It has been recommended that women with Eisenmenger's syndrome (ES) are better not to become pregnant and pregnancy may justifiably be terminated by artificial abortion to avoid high maternal mortality and coherent fetal mortality. We present a case report about a parturient with ventricular septal defect (VSD) and ES who received general anesthesia for Cesarean section (C/S) because of preeclampsia, as a result of which she finally succumbed to an episode of intraoperative hypotension in spite of vigorous cardiopulmonary resuscitation. The death was thought to be precipitated by continuous deterioration of maternal health during the 3rd trimester of gestation. The anesthetic management of pregnant ES patients in confinement was reviewed and discussed, and the possible etiological factors relevant to the tragic outcome were also explored.

Adult↗
PubMed1998

Acute hyponatremia in the perioperative period: insights into its pathophysiology and recommendations for management.

Our purpose is to review the topic of acute postoperative hyponatremia by focusing on pertinent aspects of the physiology of water and solute excretion. Four areas will be highlighted: an examination of the source of addition of electrolyte-free water, an exploration of the basis for the very large natriuresis that occurs during cerebral salt wasting following neurosurgery, possible reasons to explain why acute postoperative hyponatremia may pose a greater risk for young women [Ayus and Arieff 1996, Ayus et al. 1992, Arieff 1986, Wijdick et al. 1991], and issues related to treatment of acute hyponatremia.

Acute Disease↗
PubMed1997

Detection of specific and 'constitutive' antibody secreting cells in the gills, head kidney and peripheral blood leucocytes of dab (Limanda limanda).

The relative immunological importance of the gills of fish was investigated in terms of antibody production by enumerating antibody secreting cells (ASC) in the gills, head kidney and blood of dab (Limanda limanda) using the ELISPOT assay. The contribution of 'constitutive' ASC in the gill appeared more substantial than that of elicited specific ASC. The gills were found to contain a mean (+/- SD) of 4227 +/- 1029 'constitutive' ASC/10(6) cells which was fewer than the head kidney which contained a mean (+/- SD) of 15617 +/- 3723 'constitutive' ASC/10(6) cells but more than peripheral blood leucocytes which contained a mean (+/- SD) of 2650 +/- 212 'constitutive' ASC/10(6) cells. The number of specific anti-human gamma globulin (HGG) ASC following parenteral or oral administration of HGG was also determined. Anti-HGG ASC were detected in all three tissues following parenteral immunization, peaking simultaneously, 4 weeks post-immunization. The strongest response was found in the head kidney. After oral immunization, responses were much weaker: again the head kidney was the most active but the gill response was barely detectable. These data were complemented by measurement of specific antibody in the serum by ELISA. Serum antibody titres following immunization were found to correlate closely with the number of specific ASC in the head kidney following parenteral immunization whereas serum antibody titres after oral administration of antigen most closely followed the number of specific ASC in the blood. In the light of these data it is suggested that the primary immunological role of the leucocytes in the gill may be in the earliest stages of defence against infection.

Animals↗
PubMed1997

Changes in BRCA2 expression during progression of the cell cycle.

It has been shown that genetic alterations in BRCA1 and BRCA2 can predispose an individual to develop breast cancer. We investigated the expression of both BRCA2 and BRCA1 during the progression of the cell cycle by northern blot analysis. In MCF-10F (normal breast epithelial cell line) and MCF-7 (breast cancer cell line) cells the expression of BRCA2 RNA was low in G0 and early G1 phases then up-regulated at the G1/S phase junction. Expression of BRCA2 was maintained at relatively high levels when cells progressed through S and G2/M phases. For MCF-7 cells, the level of BRCA2 transcript decreased as cells were released from nocodazole-mediated metaphase arrest. This is consistent with the observation of low but detectable BRCA2 RNA level in G1 phase of the cell cycle. For both cell lines, the patterns of RNA expression of BRCA1 and BRCA2 were similar during the proliferation phase of cell cycle. However, the transcripts from both genes were undetectable in quiescent cells. These results suggest important functions for both BRCA2 and BRCA1 in regulation of cell growth.

BRCA2 Protein↗
PubMed1997

Suppression of tumorigenicity of breast cancer cells by an epithelial cell adhesion molecule (C-CAM1): the adhesion and growth suppression are mediated by different domains.

C-CAM1 is an epithelial adhesion molecule of immunoglobulin supergene family and has been implicated in the growth suppression of prostate cancer cells. Here we show that C-CAM1 can also suppress the tumorigenicity of breast cancer cells. These observations suggest that C-CAM1 may be a general growth suppressor in epithelial cells. In addition, we have identified the cytoplasmic domain, but not the extracellular adhesion domain, of C-CAM1 as critical for the growth suppression. Thus, the adhesion and the growth suppression functions of C-CAMI are independent of each other. Furthermore, mutation at the tyrosine phosphorylation site in the cytoplasmic domain of C-CAM1 did not obliterate C-CAM1's growth suppression function, suggesting that tyrosine phosphorylation is not involved in the signal transduction pathway leading to cell growth suppression. These studies provide the structural basis for future development of therapeutics that may selectively activate C-CAM1's growth suppression function.

Adenosine Triphosphatases↗
PubMed1997

Psychopathology in male and female HIV-positive and negative injecting drug users: longitudinal course over 3 years.

OBJECTIVE: To evaluate the impact of HIV illness on psychiatric and psychosocial functioning over 3 years in a sample of male and female HIV-positive injecting drug users (IDU), with a comparison group of HIV-negative male and female IDU. DESIGN: As part of a multidisciplinary study, 121 men (69 HIV-positive, 52 HIV-negative) and 66 women (36 HIV-positive, 30 HIV-negative) were evaluated semiannually for seven visits. Attrition, unrelated to sex or serostatus, was 33%. RESULTS: At baseline, rates of major depression and dysthymia ranged from 15% (HIV-negative men) to 33% (HIV-positive men and HIV-negative women). Global impairment was in the range found in psychiatric patients (mean Global Assessment of Functioning scores, 46-51). Higher levels of social support and less social conflict were independently associated with decreased distress and improved global functioning among both men and women. For both HIV-positive groups, degree of improvement over time was related to degree to HIV progression: those who remained healthier in terms of CD4 count and illness stage showed more improvement. HIV-seronegative status was associated with less distress for men but not for women. Overall, women reported higher levels of psychiatric distress than men. CONCLUSIONS: High rates of psychopathology were found in this IDU cohort, independent of HIV status and sex. Although rates of psychopathology, injecting drug use and distress declined slightly during the study, they remained elevated; accordingly, psychiatric services are indicated for this population.

Cohort Studies↗