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Biomedical subjects

J Song

Publications and source records attributed to J Song.

At least 307 records · Page 17Linked to original sources
PubMed1996

[Effects of temperature on the viability and infectivity of preparasitic larvae of Romanomermis yuanenesis].

Romanomermis yuanenesis (Mermithidae: Nematoda) was found in Henan, China (Song and Peng, 1987), which has a broad host range in Culicinae mosquito and has been used successfully in field test for control of culex tritaeniorhynchus, culex fatigans and Aedes albopictus in Sichuan, Yunnan, Guangxi and Henan Provinces. This study was attempted to determine the viability and infectivity of preparasitic larvae in various temperatures. The cultures containing R. yuanenesis eggs were flooded 2h with distilled water, filtered and blocked with 1% agarose. Put the filter paper into water, then the motile preparasites separated from the unhatched eggs and got through the agarose membrane into water. About 200ml water containing preparasites free from eggs were held at 26 degrees C-28 degrees C, 16 degrees C-18 degrees C and -2 degrees C to 2 degrees C for test. The motility or lack of motility was used as the criterion to distinguish the living and dead nematodes. The rate of infection of mosquitoes and the rate of parasitism of nematodes were used to show the infectivity of the preserved preparasites. The results showed that at -2 degrees C to 2 degrees C, more than 90% of preparasitic larvae of R. yuanenesis survived for 8 days and the rate of mosquito infection was 87.5% to 100%, but at 26 degrees C-28 degrees C and 16 degrees C-18 degrees C the survival times of 90% preparasites were only 24 hours and 48 hours respectively. It indicates the low temperature preservation may prolong the survival time and keep the infectivity of these preparasitic larvae.

Animals↗
PubMed1996

[Repair of acute thumb avulsion with the bi-lobed island flap of the second web].

The authors designed a bi-lobed island flap of the second web pedicled with the first and the second dorsal metacarpal arteries. Since 1993, five cases of acute thumb avulsion have been repaired using this flap. The size of the flaps ranged from 3 cm x 6 cm to 6 cm x 7 cm. All flaps survived with primary healing of the incisions. Three to nine months' follow-up showed that the flaps were thin and had sensation. The function and appearance of the reconstructed thumb were satisfactory. The bi-lobed island flap of the second web is a valuable method for the repair of thumb avulsion.

Adolescent↗
PubMed1996

[Treatment of severe hump nose].

An improved operative method has been used to treat severe hump nose in 6 cases since 1989. During the one-stage operation, the shape of the nose was remodeled by correcting the hump deformity and trimming the large lateral cartilage, alar cartilage and septal cartilage. Five cases obtained satisfactory results. One case had second operation because of callus hyperplasia. The article describes the operative design and main points of the procedure. The advantages of the method are discussed.

Adult↗
PubMed1996

[Epidermal growth factor receptor expression in laryngeal cancer].

The expression of epidermal growth factor receptor (EGFR) in 60 laryngeal carcinoma and 20 normal laryngeal mucosa was studied with immunohistochemical LSAB (labelled streptavidin biotin) method to elucidate its role in tumor progression. EGFR was negative in all 20 normal laryngeal mucosa specimens, and it was positive in 44 of 60 laryngeal carcinoma specimens. The expression of EGFR did not correlate with tumor location, tumor stage and lymph node metastasis, but correlated significantly with histological grading and the survival rate. A significantly higher positive rate was found in poorly differentiated than in moderately well differentiated tumors. The 3-year survival rate in patients with expression of EGFR was much lower than those with negative results (P < 0.01). The results suggest that EGFR may play an important role in the process of carcinogenesis in laryngeal mucosa and be used as a useful marker for the assessment of biological behavior and prognosis of laryngeal carcinoma.

Adult↗
PubMed1995

HIV nuclear import is governed by the phosphotyrosine-mediated binding of matrix to the core domain of integrase.

The karyophilic properties of the viral matrix (MA) protein govern HIV nuclear import in nondividing cells such as macrophages. A critical regulator of this process is the C-terminal tyrosine phosphorylation of MA during virus maturation. Here, we reveal the mechanism of this phenomenon, by demonstrating that tyrosine phosphorylation induces the binding of MA to integrase (IN). This leads to the incorporation of MA molecules into virus cores, and subsequently into uncoated viral nucleoprotein complexes. A direct interaction between tyrosine-phosphorylated MA and the central domain of IN can be demonstrated in vitro. It is blocked by phosphotyrosine, indicating that IN recognizes the phosphorylated C-terminal residue of MA. These results explain how the karyophilic potential of MA is conferred to the HIV nucleoprotein complex.

Base Sequence↗
PubMed1995

Regulation of somatostatin receptor mRNA expression.

The five somatostatin receptor mRNAs are expressed with distinct though overlapping patterns of distribution in the CNS and peripheral tissues. All receptor types are expressed in the anterior pituitary and hypothalamus and could therefore be modulated in states of growth hormone (GH) dysregulation. Metabolic perturbations such as food deprivation and diabetes mellitus lead to suppression of GH levels in the rat, in part due to increased somatostatin tone. In rats deprived of food, pituitary sstr1, 2 and 3 mRNAs were reduced by 80% compared to fed controls; sstr4 and sstr5 mRNAs were unchanged. Hypothalamic sstr mRNA expression was unaltered. In diabetic rats pituitary sstr1, 2 and 3 mRNAs were reduced by 50-80% with sstr1 mRNA restored in part by insulin therapy. Pituitary sstr4 mRNA and hypothalamic expression of these four types was unaffected. sstr5 mRNA is reduced by 70% in the pituitary and by 30% in the hypothalamus with restoration of both by insulin treatment. Altered pituitary sstr expression in food deprivation and diabetes could result from chronic exposure to increased plasma somatostatin. In rat GH3 pituitary tumour cells exposed to 1 microM somatostatin for up to 48 h, sstr1, 3, 4 and 5 mRNA increased dramatically while sstr2 mRNA exhibited a biphasic response. We observed a net increase in receptor binding associated with increased sstr mRNA. Somatostatin receptor expression is regulated in a tissue- and type-specific manner, adding further complexity to the action of the multifaceted peptide somatostatin.

Animals↗
PubMed1995

Kinetics of the inhibition of axonal defasciculation and arborization mediated by carbohydrate markers in the embryonic leech.

We studied carbohydrate interactions that mediate the targeting of sensory afferents in the synaptic neuropil of segmental central nervous system (CNS) ganglia in the embryonic leech. First, we determined the rate of sensory afferent development in vivo, and then we devised a culture system that permits the normal patterning of their projections in the CNS and PNS to proceed at 92% the normal rate. Using this in vitro system, we analyzed the mannose-specific recognition that mediates the defasciculation and arborization of sensory afferents in the CNS neuropil after they have tracked through peripheral nerves as a tight axon bundle. Sensory afferent defasciculation and arborization in the neuropil were inhibited by culturing embryos in Fab fragments directed against the mannose-containing surface epitope of sensory afferents. We demonstrate that the rate at which separately extending axons or their branches are lost from the neuropil can be modeled by a first-order decay process. These kinetic studies indicate that the loss of each separately extending axon or branch is an independent event. This suggests that sensory afferent projections extend autonomously across the target region in the search of their appropriate postsynaptic partners.

Animals↗
PubMed1995

Simultaneous detection by consensus multiplex PCR of high- and low-risk and other types of human papilloma virus in clinical samples.

A consensus multiplex PCR (CM-PCR) technique was developed to detect high-risk (HPV 16/18), low-risk (HPV 6/11), and over 40 other types of human papillomavirus (HPV), separately but simultaneously, by mixing three pairs of consensus primers in the same PCR mixture, for gene amplification. Simultaneous detection of three groups of HPV DNA provides valuable information for clinical practice and this procedure is simple and convenient for routine laboratory examinations. We detected HPV DNA sequences in plasmid HPV DNA and DNA extracted from tissues of condyloma acuminata and cervical carcinoma and from exfoliated cells of the lower genital tract of healthy Chinese women living in the People's Republic of China. We confirmed that this simple, convenient, and cost-beneficial CM-PCR technique is reliable for the detection of HPV DNA sequences.

Adolescent↗
PubMed1995

Damage and recovery of hair cells in fish canal (but not superficial) neuromasts after gentamicin exposure.

Recent evidence demonstrating the presence of two types of sensory hair cell in the ear of a teleost fish (Astronotus ocellatus, the oscar) indicates that hair cell heterogeneity may exist not only in amniotic vertebrates but also in anamniotes. Here we report that a similar heterogeneity between hair cell types may also occur in the other mechanosensory organ of the oscar, the lateral line. We exposed oscars to the aminoglycoside (ototoxic) antibiotic gentamicin sulfate and found damaged sensory hair cells in one class of the lateral line receptors, the canal neuromasts, but not in the other class, the superficial neuromasts. This effect was not due to the canal environment. Moreover, new ciliary bundles on hair cells of the canal neuromasts were found after, and during, gentamicin exposure. The pattern of hair cell destruction and recovery in canal neuromasts is similar to that of type I-like hair cells found in the striolar region of the utricle and lagena of the oscar after gentamicin treatment. These results suggest that the hair cells in the canal and superficial neuromasts may be similar to type I-like and type II hair cells, respectively, in the fish ear.

Animals↗
PubMed1995

Targeting of neuronal subsets mediated by their sequentially expressed carbohydrate markers.

The targeting of sensory afferent neurons in the leech CNS occurs in two discrete steps that are mediated via different carbohydrate recognitions, as shown by molecular perturbations of cultured embryos. A constitutive carbohydrate marker that is generic to all of these neurons mediates their initial defasciculation and arborization across the entire target region via mannose-specific recognition. Subsequently, two subsets of these same neurons can be differentiated by their expression of other markers that are located on hybrid or complex type carbohydrate chains. These developmentally regulated carbohydrate markers then mediate the target assembly of their respective neuronal subsets into discrete subregions. Thus, by performing opposing functions in a temporal sequence, constitutive and developmentally regulated carbohydrate markers collaborate in the targeting of neuronal subsets in the CNS.

Afferent Pathways↗
PubMed1995

Development of immortalized endometrial epithelial and stromal cell lines from the mink (Mustela vison) uterus and their effects on the survival in vitro of mink blastocysts in obligate diapause.

Mink endometrial cell lines were established by stable transfection of a plasmid vector encoding the SV40 large T antigen driven by the human beta-actin promoter. A second plasmid vector, pSV2neo, was employed for selection of transfected cells. Specificity and homogeneity of consequent cell lines were evaluated by immunocytochemistry employing antibodies against cytokeratin, desmin, and vimentin. Cytokeratin was found exclusively in epithelial cells, whereas vimentin appeared primarily in stromal cells. Neither cell line showed detectable desmin activity. These cell lines along with Buffalo rat liver (BRL) cells were employed in coculture with mink embryos in obligate diapause. Mink stromal and BRL cell lines were most effective in enhancing embryo survival in vitro. The percentages of cocultured embryos that survived for 72 h or more were 65% with epithelial cells, 75% with stromal cells, 68% with the combination of stromal and epithelial cells, and 93% with BRL cells. Only 23% of the embryos cultured without cells survived beyond 48 h. Embryo growth was also observed; some embryos in coculture showed trophoblastic outgrowth and adhesion to the cell surfaces. These results demonstrate that mink embryos in obligate delay can survive and develop in culture and that coculture with uterine or BRL cells increases the length and frequency of survival.

Alkaline Phosphatase↗
PubMed1995

Inhibition of G-protein signaling by dominant gain-of-function mutations in Sst2p, a pheromone desensitization factor in Saccharomyces cerevisiae.

Genetic analysis of cell-cell signaling in Saccharomyces cerevisiae has led to the identification of a novel factor, known as Sst2p, that promotes recovery after pheromone-induced growth arrest (R. K. Chan and C. A. Otte, Mol. Cell. Biol. 2:11-20, 1982). Loss-of-function mutations lead to increased pheromone sensitivity, but this phenotype is partially suppressed by overexpression of the G protein alpha subunit gene (GPA1). Suppression is allele specific, however, suggesting that there is direct interaction between the two gene products. To test this model directly, we isolated and characterized several dominant gain-of-function mutants of SST2. These mutations block the normal pheromone response, including a loss of pheromone-stimulated gene transcription, cell cycle growth arrest, and G protein myristoylation. Although the SST2 mutations confer a pheromone-resistant phenotype, they do not prevent downstream activation by overexpression of G beta (STE4), a constitutively active G beta mutation (STE4Hpl), or a disruption of GPA1. None of the SST2 alleles affects the expression or stability of G alpha. These results point to the G protein alpha subunit as being the direct target of Sst2p action and underscore the importance of this novel desensitization factor in G-protein-mediated signaling.

Cell Division↗