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Biomedical subjects

A Lin

Publications and source records attributed to A Lin.

At least 91 records · Page 5Linked to original sources

[Treatment of recurrent anterior dislocation of the shoulder with pectoralis minor muscle-bone flap].

We treated 10 patients with recurrent anterior dislocation of the shoulder by transplantation of pectoralis minor muscle-bone flap transplanted to the upper part of the humerus. All patients were followed-up for an average 31 months and no recurrent was found. We consider that the muscle beily exerts a protective effect like a barrier on the weak anterio inferior region of the shoulder and increases the force for extending the shoulder and lifting the arm. The operation is based on biomechanics. Meanwhile, suturing the laxative joint capsule and repairing the weak anteroinfeior region of the shoulder is more beneficial to prevent from redislocation of the humerus head.

Adult↗

Selective activation of the JNK signaling cascade and c-Jun transcriptional activity by the small GTPases Rac and Cdc42Hs.

The Rho subfamily of GTPases is involved in control of cell morphology in mammals and yeast. The mammalian Rac and Cdc42 proteins control formation of lamellipodia and filopodia, respectively. These proteins also activate MAP kinase (MAPK) cascades that regulate gene expression. Constitutively activated forms of Rac and Cdc42Hs are efficient activators of a cascade leading to JNK and p38/Mpk2 activation. RhoA did not exhibit this activity, and none of the proteins activated the ERK subgroup of MAPKs. JNK, but not ERK, activation was also observed in response to Dbl, an oncoprotein that acts as a nucleotide exchange factor for Cdc42Hs. Results with dominant interfering alleles place Rac1 as an intermediate between Ha-Ras and MEKK in the signaling cascade leading from growth factor receptors and v-Src to JNK activation. JNK and p38 activation are likely to contribute to the biological effects of Rac, Cdc42Hs, and Dbl on cell growth and proliferation.

3T3 Cells↗

Identification of a dual specificity kinase that activates the Jun kinases and p38-Mpk2.

One Ras-dependent protein kinase cascade leading from growth factor receptors to the ERK (extracellular signal-regulated kinases) subgroup of mitogen-activated protein kinases (MAPKs) is dependent on the protein kinase Raf-1, which activates the MEK (MAPK or ERK kinase) dual specificity kinases. A second protein kinase cascade leading to activation of the Jun kinases (JNKs) is dependent on MEKK (MEK kinase). A dual-specificity kinase that activates JNK, named JNKK, was identified that functions between MEKK and JNK. JNKK activated the JNKs but did not activate the ERKs and was unresponsive to Raf-1 in transfected HeLa cells. JNKK also activated another MAPK, p38 (Mpk2; the mammalian homolog of HOG1 from yeast), whose activity is regulated similarly to that of the JNKs.

Amino Acid Sequence↗

A randomized trial of extra-amniotic saline infusion versus laminaria for cervical ripening.

OBJECTIVE: To compare extra-amniotic saline infusion versus laminaria for cervical ripening and labor induction. METHODS: Patients of at least 34 weeks' gestation with a Bishop score of 3 or less were randomized to either laminaria ripening for 6 hours or more followed by oxytocin induction versus initiation of extra-amniotic saline infusion at the start of oxytocin induction. Indications for induction included 41 weeks' gestation or greater, hypertensive disease, diabetes, oligohydramnios, suspect fetal growth, and nonreassuring fetal testing. RESULTS: There were no significant differences in maternal age, race, parity, gestational age, or indications for induction between the two groups (extra-amniotic saline infusion group, n = 26, laminaria group, n = 26). After only 3 hours of oxytocin induction, patients in the extra-amniotic saline infusion group achieved an identical distribution of Bishop scores compared with the patients in the laminaria group after 6 hours or more of pre-induction ripening as well as 3 hours of oxytocin induction. There were no differences in rates of cesarean delivery (extra-amniotic saline infusion 35%, laminaria 35%), infectious complications, or neonatal outcomes between the two groups. The induction-to-delivery interval (+/- standard deviation) was significantly shortened with extra-amniotic saline infusion (extra-amniotic saline infusion 12.9 +/- 5.7 hours versus laminaria 16.9 +/- 7.1 hours, P = .03). In addition, fewer cesarean deliveries were performed for failed inductions (cervix less than 5 cm dilated) in the extra-amniotic saline infusion group (one of 26 versus six of 26, P = .049). CONCLUSION: Extra-amniotic saline infusion offers potential advantages over the use of laminaria. Extra-amniotic saline infusion saves a significant amount of time both by obviating the need for pre-induction cervical ripening and in shortening the induction-to-delivery interval. Also, fewer patients required cesarean delivery for failed induction of labor with extra-amniotic saline infusion.

Adult↗

Production of type II ribotoxins by Aspergillus species and related fungi in Taiwan.

A molecular investigation was conducted on the production of type II ribotoxin of the species Aspergillus and related fungi in Taiwan. Species that carried ribotoxin were confirmed by (1) cross-reactivity to anti-alpha-sarcin serum; (2) Southern dot hybridization; (3) PCR amplification of genomic DNA with specific primers; and (4) analysis of ribotoxic activity. Five new strains, A. clavatus, A. oryzae var. effusus, A. ostianus, A. tamarii, and Neosartorya fischeri var. spinosa, were identified to contain an alpha-sarcin-like ribotoxin. These positive strains exhibit ribotoxic activity by cleaving ribosomes and generating an alpha-fragment.

Animals↗

Adsorption of charged non-albumin bound drugs by amorphous silica.

We investigated the in vitro drug adsorption of PQ 10150 sodium silicate gel (AIS, Santa Clara, CA) with particle size of 230 microns and surface area of 400 m2/g. We observed 99% to 88% adsorption of gentamicin; a mean 91% of disopyramide; a mean 89% of quinidine at low concentration, falling to 75% at higher concentration. Insulin was 88% adsorbed at low concentrations but less so (65%) at higher concentrations. We observed a mean 83% adsorption of procainamide, a mean 84% of N-acetyl procainamide, 74% of lidocaine, 73% of amitriptyline, and 44% of desipramine. We found an average of 14% reduction of total digoxin concentration when serum containing digoxin (2 to 33 ng/mL) was exposed to sodium silicate, while the reduction in free digoxin concentration was 16%. Five percent ethosuximide was also removed. The adsorption of theophylline, phenobarbital, acetaminophen, phenytoin, ethylene glycol, methotrexate, salicylate, thiocyanate and diazepam was minimal and not significant. We conclude that significant amounts of charged, non-albumin bound drugs can be removed by PQ 10150 sodium silicate gel.

Adsorption↗

[Treatment of maxillofacial vascular malformation by arterial embolism and application of sclerosing agent].

30 cases of large cavernous and racemose hemangioma of the maxillofacial were treated selectively with arterial embolism of the tumor and inject Xiaozhiling into the tumor, from November 1990 to November 1993. This method has exact effect either to racemose or to cavernous hemangioma, without facial defect and functional damage. All the patients were followed up 6 months to 3 years. 27 cases were cured, 1 failed, 1 gave up treatment, 1 died of complication. Its mechanism, indications, prevention of complications and recurrence were discussed.

Adolescent↗

Differential activation of ERK and JNK mitogen-activated protein kinases by Raf-1 and MEKK.

Growth factors activate mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated kinases (ERKs) and Jun kinases (JNKs). Although the signaling cascade from growth factor receptors to ERKs is relatively well understood, the pathway leading to JNK activation is more obscure. Activation of JNK by epidermal growth factor (EGF) or nerve growth factor (NGF) was dependent on H-Ras activation, whereas JNK activation by tumor necrosis factor alpha (TNF-alpha) was Ras-independent. Ras activates two protein kinases, Raf-1 and MEK (MAPK, or ERK, kinase) kinase (MEKK). Raf-1 contributes directly to ERK activation but not to JNK activation, whereas MEKK participated in JNK activation but caused ERK activation only after overexpression. These results demonstrate the existence of two distinct Ras-dependent MAPK cascades--one initiated by Raf-1 leading to ERK activation, and the other initiated by MEKK leading to JNK activation.

3T3 Cells↗

Acute inflammatory injury in the lung precipitated by oxidant stress induces fibroblasts to synthesize and release transforming growth factor-alpha.

Although transforming growth factor-alpha (TGF-alpha) is widely distributed in transformed cells and in some normal cells and much is known about its structure and metabolism, there is little information about its physiological actions. TGF-alpha is not thought to be synthesized by nontransformed fibroblasts, but it is thought to be a mitogen for these and epithelial cells (Derynck, R. (1986) J. Cell. Biochem. 32, 293-304). We report here that fibroblasts obtained from hamsters with oxidant-induced lung injury release TGF-alpha at levels comparable with those reported for transformed cells. In conditioned media, one isoform of 18 kDa was recognized by a monoclonal antibody to mature TGF-alpha; five isoforms ranging from 18 to 42 kDa were recognized in cell lysates. Conditioned media from these fibroblasts stimulated tyrosine phosphorylation of the epidermal growth factor (EGF)/TGF-alpha receptor, competed with radioactive EGF for binding sites on A431 cells, and were mitogenic for mesenchymal and epithelial cells. This mitogenic activity could be almost completely blocked by anti-TGF-alpha. Conditioned media from normal lung fibroblasts exhibited none of these activities. Using normal lung fibroblasts, we found that TGF-alpha synthesis could be induced in vitro with 25 nmol/ml EGF, suggesting that the induction in vivo may have been due, in part, to a stimulation by EGF (or TGF-alpha) released by other cell types such as alveolar macrophages recruited to the injury site. TGF-alpha is, in general, a mitogen for epithelial cells (Derynck, 1986); more specific to acute injury in the lung, it may affect the proliferation (Ryan, R. M., Mineo-Kuhn, M. M., Kromer, C. M., and Finkelstein, J. N. (1994) Am. J. Physiol. 266, L17-L23) and metabolic activities (Whitsett, J. A., Weaver, T. E., Lieberman, M. A., Clark, J. G., and Daugherty, C. (1987) J. Biol. Chem. 262, 7908-7913) of alveolar epithelial type II cells. This is, we believe, the first report of a fibroblast-derived TGF-alpha induced with oxidant injury. If this response was ubiquitously manifested in other tissues, then fibroblast-derived TGF-alpha might be an important determinant of the epithelial and mesenchymal hyperplasia commonly observed in tissue repair.

Acute Disease↗

Three unrelated cases of paracentric inversions of 1p in individuals with abnormal phenotypes.

Paracentric inversions, involving a rearrangement within one chromosome arm, are rare. Although carriers of balanced paracentric inversions should theoretically not be at risk for abnormal offspring, such cases have been reported. We report on 2 unrelated cases of inherited paracentric inversions of 1p with breakpoints at p32 and p36.1 and p32.3 and p36.22 in individuals with abnormal phenotypes. Another case of 2 abnormal monozygotic twins with a de novo paracentric inversion of 1p with breakpoints at p22 and p34 is presented as well.

Abnormalities, Multiple↗

c-Jun N-terminal phosphorylation correlates with activation of the JNK subgroup but not the ERK subgroup of mitogen-activated protein kinases.

c-Jun transcriptional activity is stimulated by phosphorylation at two N-terminal sites: Ser-63 and -73. Phosphorylation of these sites is enhanced in response to a variety of extracellular stimuli, including growth factors, cytokines, and UV irradiation. New members of the mitogen-activated protein (MAP) kinase group of signal-transducing enzymes, termed JNKs, bind to the activation domain of c-Jun and specifically phosphorylate these sites. However, the N-terminal sites of c-Jun were also suggested to be phosphorylated by two other MAP kinases, ERK1 and ERK2. Despite these reports, we find that unlike the JNKs, ERK1 and ERK2 do not phosphorylate the N-terminal sites of c-Jun in vitro; instead they phosphorylate an inhibitory C-terminal site. Furthermore, the phosphorylation of c-Jun in vivo at the N-terminal sites correlates with activation of the JNKs but not the ERKs. The ERKs are probably involved in the induction of c-fos expression and thereby contribute to the stimulation of AP-1 activity. Our study suggests that two different branches of the MAP kinase group are involved in the stimulation of AP-1 activity through two different mechanisms.

Animals↗

Tricholin, a new antifungal agent from Trichoderma viride, and its action in biological control of Rhizoctonia solani.

Tricholin, a ribosome-inactivating protein isolated from the culture broth of Trichoderma viride, has been shown to exert fungicidal effects on Rhizoctonia solani through a multi-hit kinetic interaction. Tricholin causes a parallel cessation of growth, uptake of amino acids, and protein biosynthesis. The in vivo mode of action of tricholin on protein synthesis and cell growth appears to be attributed to the diminishing of the polysome formation in R. solani through damage to large ribosomal subunits. These results concur with previous data and prove that tricholin is an effective inhibitor of protein synthesis. The efficacy of tricholin as an antibiotic agent was estimated to have a duration of approximately 42 hours.

Antifungal Agents↗

[Epidemiology and control of hookworm infection in Fujian province].

Fujian province has been known to be endemic for mixed hookworm infection with Ancylostoma duodenale as the predominant species. The infection rate was 50% before 1980. As a result of mass treatment starting from 1980, the infection rate was decreased in most areas. And, infection foci were changed from sweet potato fields to the banana, sweatcane and asparagus fields where the infection rate tended to increase. It is stressed that the current endemic characteristics of hookworm infection should be paid more attention in implementing the control programme of hookworm infection.

Adolescent↗

The significance of eccentric foci of hyperpigmentation ('small dark dots') within melanocytic nevi. Analysis of 59 cases.

BACKGROUND AND DESIGN: Fifty-nine melanocytic nevi with eccentric foci of hyperpigmentation ("small dark dots") that measured primarily 1 to 2 mm in diameter were prospectively examined to determine the histologic correlates of the dark dots. RESULTS: Forty-one (69%) of the dark dots were due to increased melanin in epidermal melanocytes and/or keratinocytes, usually accompanied by melanophages; of these 41, six (15%) were associated with slight or moderate melanocytic nuclear atypia. Fifteen (25%) of the dark dots were due to increased dermal pigment that was either superficial or deep. Three (5%) of the dark dots were due to melanoma arising within a nevus. CONCLUSIONS: A small percentage of "small dark dots" within melanocytic nevi are due to melanoma. Biopsy specimens of nevi with small dark dots should be sectioned to ensure histologic examination of this focus of hyperpigmentation.

Adolescent↗

Purification and properties of a human platelet inositol 1,4,5-trisphosphate 3-kinase.

An inositol 1,4,5-trisphosphate 3-kinase (Ins(1,4,5)P3 3-kinase) has been purified 943-fold from a 30,000g human platelet extract and has a specific activity of 283 nmol/min/mg protein and an apparent Km for inositol 1,4,5-trisphosphate of 0.76 microM; the optimal pH for the enzymatic activity was 7.2. Under both denaturing and nondenaturing conditions, the kinase preparation contained two polypeptides, both of which exhibited Ca2+/calmodulin-dependent Ins(1,4,5)P3 3-kinase activity. In the presence and absence of calmodulin, Ins(1,4,5)P3 3-kinase exhibited a biphasic response to Ca2+, being stimulated between 10(-7) and 10(-6) M Ca2+ and inhibited when the Ca2+ level was further increased. Ins(1,4,5)P3 3-kinase was stimulated by calmodulin approximately 10-fold, requiring 55 nM calmodulin for a half-maximal effect. Calmodulin stimulation was immediately reversed upon chelation of Ca2+ by ethylene glycol bis (beta-amino-ethyl ether) N,N'-tetraacetic acid consistent with a mechanism of activation involving a direct interaction of calmodulin with Ins(1,4,5)P3 3-kinase. Since we have previously shown that Ins(1,4,5)P3 3-kinase can also be phosphorylated and consequently inactivated by protein kinase C in vitro (Lin, A. N., Barnes, S., and Wallace, R. W., 1990, Biochem. Biophys. Res. Commun. 170, 1369-1376), Ins(1,4,5)P3 3-kinase appears to be a key enzyme in the inositol phosphate signaling pathway and as such may play an important role in human platelet function.

Animals↗