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Biomedical subjects

B Hu

Publications and source records attributed to B Hu.

At least 181 records · Page 10Linked to original sources
PubMed1998

[Genetic diagnosis of alpha and beta thalassemia dual heterozygote].

OBJECTIVE: To perform genetic diagnosis of alpha and beta thalassemia dual heterozygotes. METHODS: PCR and beta-thalassemia allele specific oligonucleotide probe/reverse dot blot(ASO/RDB) techniques were used. RESULTS: Six cases of suspected alpha-thalassemia-1 and beta-thalassemia dual heterozygotes were found in genetic counseling and prenatal diagnosis. On genetic diagnosis, they were all Southeast Asia(SEA) type of alpha-thalassemia-1 and beta-thalassemia (--SEA/alpha alpha, beta T/beta A) dual heterozygotes. Out of them, 3 cases were alpha-thalassemia-1 and beta 41-42 (-TCTT), 2 were alpha-thalassemia-1 and beta-28(A-->T) and 1 was alpha-thalassemia-1 and beta IVS-II-654(C-->T) double heterozygotes. CONCLUSION: The detection of thalassemia dual heterozygotes facilitates the prenatal diagnosis with more precision.

Adult↗
PubMed1998

[An internet based medical communication server].

The telemedicine and medical conference usually need multi-point to multi-point communication. Because the communication users can be patients, specialists or medical centers, they have different communication ratios and different physical connection, therefore, this kind of communication is complicated and limited by the communication ratios. In this paper, to meet the requirements of medical communication, we presented a concept of medical communication server which is able to receive data packages and deliver them according to the request of clients, and described its implementation in Windows 95 environment by using Windows Sockets.

Computer Systems↗
PubMed1998

[The technique of chronic infusion of drugs into the cochlea by an osmotic pump].

OBJECTIVE: To introduce a method of chronic infusion of drugs into the cochlea using a osmotic pump. METHODS: A stainless steel tube was surgically implanted into the basal turn of the chinchilla cochlea and connected to the pump. To assess the reliability of the procedure, and the pump, Hank's solution or L-buthionine-[S,R]-sulfoximine (BSO) was infused into the cochlea by this pump and inferior colliculus (IC) potential and hair cell morphology were examined. RESULTS: In three Hank's solution infused cochleas, the thresholds of IC potential were kept in the normal level and no hair cell loss was found 14 days after the beginning of the infusion, suggested that the pump implantation and Hank's solution infusion had no significant effects on the cochlear functions. In contrast, threshold shifts of IC potentials and hair cell loss were found in two BSO infused animals, suggested that the infused solution had distributed into the whole cochlea. CONCLUSION: This study indicates that the osmotic pump can be used in chronic delivery of experimental drugs into the cochlea.

Animals↗
PubMed1998

Association of primary intracranial meningioma and cutaneous meningioma of external auditory canal: a case report and review of the literature.

A cutaneous meningioma of the external auditory canal occurred in a 48-year-old Filipino woman who had undergone subtotal resection of a dural-based intracranial meningioma at the ipsilateral cerebellopontine angle 36 months previously. Radiologic findings demonstrated a recurrence of intracranial meningioma with surface erosion and heterogeneous densities of the mastoid bone, without extension to the area of the external auditory canal. Meningioma in the external ear canal is extremely rare. To our knowledge, there have been only two previously reported cases, both without intracranial lesion. In this case, the auditory canal lesion may represent either an ectopic meningioma arising from an arachnoid cell rest or an occult direct extension from intracranial menigioma.

Actins↗
PubMed1998

Localization of p75 neurotrophin receptor in the retina of the adult SD rat: an immunocytochemical study at light and electron microscopic levels.

The low-affinity neurotrophin receptor p75(NTR), or p75, is a 75-kDa cell surface glycoprotein that binds all neurotrophins with similar affinity and is thought to help to ensure the specificity of each neurotrophin. In order to better understand the role of p75 and how it is involved in the neurotrophic effects in the retina, we have examined its cellular localization in the adult rat retina by immunocytochemistry at both light and electron microscopic levels. The similarity between the staining pattern of p75 and that of the distribution of Müller cell processes, as marked by antibodies against S-100 and vimentin, suggests that p75 may be on the Müller cell processes and not on the retinal ganglion cells (RGCs) as previously reported. The failure to detect p75 immunoreactivity on Fluoro-Gold retrogradely labeled RGCs in the radially sectioned retinae also indicates that it is not expressed on RGCs. The results from the light microscopic immunohistochemical studies are supported at the ultrastructural level, showing that p75-immunopositive staining is localized on Muller cell processes and not on RGC bodies. Muller cell processes not only form the inner limiting membrane but also partially wrap around the RGC bodies. Our results lead us to conclude that the previously reported immunopositive staining of p75 on RGCs might belong to the surrounding Miller cell processes. Thus, the pathway of neurotrophic effects on RGCs might be, at least partially, through a glial-neuronal pathway rather than on RGCs directly.

Animals↗
PubMed1997

The eye-specification proteins So and Eya form a complex and regulate multiple steps in Drosophila eye development.

Sine oculis (so) and eyes absent (eya) are required for Drosophila eye development and are founding members of the mammalian Six and Eya gene families. These genes have been proposed to act with eyeless (Pax6) to regulate eye development in vertebrates and invertebrates. so encodes a highly diverged homeobox transcription factor and eya encodes a novel nuclear protein. We demonstrate that So and Eya (1) regulate common steps in eye development including cell proliferation, patterning, and neuronal development; (2) synergize in inducing ectopic eyes; and (3) interact in yeast and in vitro through evolutionarily conserved domains. We propose that an So/Eya complex regulates multiple steps in eye development and functions within the context of a network of genes to specify eye tissue identity.

Animals↗
PubMed1997

Theophylline accelerates human granulocyte apoptosis not via phosphodiesterase inhibition.

Theophylline, in addition to its bronchodilator effect, is reported to have an antiinflammatory action that may account for its clinical effectiveness in the reduction of inflammatory cells in the airway. In bronchial asthma, such inflammatory cytokines as GM-CSF and IL-5 are upregulated and have been proposed to cause granulocyte infiltration (neutrophils and eosinophils) in the airway by inhibition of granulocyte apoptosis. We examined the abilities of theophylline to counteract the prolongation of human granulocyte survival caused by cytokines. Theophylline was shown to shorten granulocyte survival in a dose-dependent manner. Upon incubation with a therapeutical concentration of theophylline (0.1 mM; 18 microg/ml), percentages of GM-CSF (10 ng/ml)-induced delayed apoptosis increased from 18+/-2% to 38+/-3% (p < 0.02) in neutrophils and from 21+/-2% to 35+/-2% (p < 0.02; 24-h incubation) in eosinophils. The percentage of IL-5 (5 ng/ml)-induced delayed eosinophil apoptosis also increased from 22+/-4% to 33+/-2% (P < 0. 05). In contrast, cyclic AMP (cAMP)-increasing agents (3-isobutylmethylxanthine, dibutyryl cAMP, and rolipram) inhibited granulocyte apoptosis in the control and anti-Fas antibody-treated cells. In eosinophils, the expression of bcl-2 protein decreased after incubation with theophylline. These findings suggest that theophylline accelerates granulocyte apoptosis, which may play an essential role in inflammation, and controls granulocyte longevity regardless of the elevation of intracellular cAMP levels.

1-Methyl-3-isobutylxanthine↗
PubMed1997

Identification of genes required for Drosophila eye development using a phenotypic enhancer-trap.

A novel method of P-element mutagenesis is described for the isolation of mutants affecting the development of the Drosophila compound eye. It exploits the interaction between the Bride of Sevenless (Boss) ligand and the Sevenless (Sev) receptor tyrosine kinase that triggers the formation of the UV-sensitive photoreceptor neuron, R7. Transposition of a boss cDNA transgene, in an otherwise boss mutant background, was used as a "phenotypic trap" in live flies to identify enhancers expressed during a narrow time window in eye development. Using a rapid behavioral screen, more than 400,000 flies were tested for restoration of R7. Some 1,800 R7-containing flies were identified. Among these, 21 independent insertions with expression of the boss reporter gene in the R8 cell were identified by a external eye morphology and staining with an antibody against Boss. Among 900 lines with expression of the boss reporter gene in multiple cells assessed for homozygous mutant phenotypes, insertions in the marbles, glass, gap1, and fasciclin II genes were isolated. This phenotypic enhancer-trap facilitates (i) the isolation of enhancer-traps with a specific expression pattern, and (ii) the recovery of mutants disrupting development of specific tissues. Because the temporal and tissue specificity of the phenotypic trap is dependent on the choice of the marker used, this approach can be extended to other tissues and developmental stages.

Animals↗
PubMed1997

The electrogenic effects of Na(+)-K(+)-ATPase in rat auditory thalamus.

1. The electrogenic effects of the Na(+)-K(+)-ATPase in thalamic neurones were investigated by means of intracellular and whole-cell patch-clamp recording techniques in rat medial geniculate body (MGB) maintained in vitro. 2. In twenty-six out of thirty-one neurones recorded intracellularly, application of the Na(+)-K+ pump inhibitor strophanthidin induced two different types of membrane depolarization: a small, reversible depolarization with a peak amplitude of 4 +/- 2.6 mV or a prolonged depolarization of large amplitude (48.6 +/- 9.0 mV) with or without a decrease in apparent membrane resistance. Blockade of glutamate receptors with kynurenic acid or 6-cyano-7-nitroquinoxaline-2,3-dione and (+/-)-2-amino-5-phosphonopentanoic acid did not prevent either type of pump response, but the large depolarization was not seen when the medium contained the sodium channel blocker TTX. 3. Whole-cell patch-clamp recording showed that the small membrane depolarization is mediated by an inward membrane current (39.00 +/- 5.70 pA) that exhibited a weak voltage dependence. An inward current of similar amplitude was also induced in MGB cells when the pipette solution contained nominally zero Na+ or when K+ was temporarily omitted from the extracellular medium. The large membrane depolarization or the corresponding membrane current was not observed in whole-cell conditions. 6. Transient inhibition of the electrogenic Na(+)-K(+)-ATPase consistently led to a change in the mode of synaptic transmission in MGB cells, during which the synaptically evoked burst response was either blocked or converted into a single spike discharge. 7. Taken together, these data suggest that blockade of the electrogenic pump produces a dual membrane effect in mammalian thalamic neurones: a small electrogenic membrane depolarization and a large depolarization response that can be prevented by artificially maintaining the transmembrane ionic gradients. The electrogenic activity of the Na(+)-K(+)-ATPase may play an important role in setting the mode of synaptic transmission in sensory thalamus.

Animals↗
PubMed1997

Differential Na(+)-K(+)-ATPase activity in rat lemniscal and non-lemniscal auditory thalami.

1. Using whole-cell recording and confocal immunofluorescent microscopy, we have investigated the differential electrogenic activity, subunit expression and subcellular distribution of the Na(+)-K(+)-ATPase in the lemniscal (ventral) and non-lemniscal (dorsal) pathways of the rat medial geniculate body (MGB) in vitro. 2. Bath application of Na(+)-K(+)-ATPase inhibitors strophanthidin or dihydro-ouabain produced a transient, dose-dependent inward current or membrane depolarization which were significantly larger in dorsal MGB neurones than in ventral cells (45.9 +/- 6.45 vs. 24.3 +/- 4.1 pA; P < 0.05). Electrophysiological and morphometric measurements showed that the dorsal MGB neurones had a significantly lower input conductance and a smaller somata than their ventral counterparts. The level of the resting membrane potential also differed by about 6 mV between the two cell populations, with the dorsal cells being more hyperpolarized (-74.2 +/- 0.6 vs. -67.7 +/- 1.3 mV; P < 0.001). 3. Incubation of enzymatically dissociated MGB neurones with fluorescent monoclonal antibodies against alpha 1-alpha 3 isoforms of Na(+)-K(+)-ATPase showed that both dorsal and ventral cells expressed primarily alpha 3 subunits. Confocal laser scanning revealed, however, that the mean pixel density of alpha 3 fluorescent antibodies in the plasma membrane domain, but not in the cytoplasmic compartment, was about 40% higher in dorsal neurones than in the ventral cells (29.7 +/- 4.7 vs. 16.9 +/- 2.3 grey shadow per pixel; P < 0.05). 4. The above results suggest that the electrogenic activity of the Na(+)-K(+)-ATPase is differentially regulated between lemniscal and non-lemniscal auditory thalami through a mechanism that probably involves differential pump densities in the cell membrane.

Animals↗
PubMed1997

Genetic immunization for the melanoma antigen MART-1/Melan-A using recombinant adenovirus-transduced murine dendritic cells.

Dendritic cells (DCs) are professional antigen-presenting cells that process and present antigenic peptides and are capable of generating potent T-cell immunity. A murine tumor model was developed to evaluate methods of genetic immunization to the human MART-1/Melan-A (MART-1) melanoma antigen. A poorly immunogenic murine fibrosarcoma line (NFSA) was stably transfected with the MART-1 gene. This transfected tumor [NFSA(MART1)] grows progressively in C3Hf/Kam/Sed (H-2k) mice. Partial protection against a challenge with NFSA(MART1) could be achieved with i.m. injections of a MART-1 expression plasmid or with systemic administration of an adenovirus vector expressing MART-1. However, superior protection was achieved when granulocyte macrophage colony-stimulating factor/interleukin-4-differentiated murine DCs transduced with an adenovirus vector expressing MART-1 were used for immunization. Both partial and complete protection could be achieved with i.v. administration of MART-1-engineered DCs. Splenocytes from immunized mice contained MHC class 1-restricted CTLs specific for MART-1. This preclinical model of genetic immunization supports a therapeutic strategy for human melanoma.

Adenoviridae↗
PubMed1997

Mechanism of colchicine impairment on learning and memory, and protective effect of CGP36742 in mice.

Fourteen days after hippocampal microinfusion with colchicine (COL), learning and memory ability of mice was significantly impaired, while glutamate (Glu), gamma-aminobutyric acid (GABA), Glu/GABAB and GABAB receptor levels in the cortex and/or the hippocampus were significantly changed. After treatment with a GABAB receptor antagonist, CGP36742, learning and memory impairment caused by COL could be significantly improved, and the above indices in brain regions reversed. These results suggest GABAB antagonists may have therapeutic value in the treatment of Alzheimer's disease.

Animals↗
PubMed1997

Effect of cell density and growth factors on matrix GLA protein expression by normal rat kidney cells.

The present studies demonstrate that the expression of the vitamin K-dependent matrix Gla protein (MGP) is critically dependent on cell density in culture. Subculture of confluent NRK cells to 1/30 of the confluent cell density causes a 50- to 100-fold decline in MGP expression per cell within two days. MGP expression subsequently increases with increasing cell density and eventually attains a level of expression per cell at five days post-confluence that is over 2,000-fold greater than was seen in the cells two days after the 1 to 30 subculture. These reversible, density-dependent changes in MGP expression are far larger than have been previously reported for other secreted proteins and suggest that the as yet unknown function of MGP requires its expression at high cell density but not at low. We have also observed that human epidermal growth factor (EGF) causes a 20-fold reduction in MGP expression in post-confluent, non-dividing cultures and suggest that the suppression of MGP function at high density may be a prelude to cell migration or division in response to appropriate signals.

Animals↗
PubMed1997

Metastasis of an intracranial germinoma through a ventriculoperitoneal shunt: recurrence as a yolk-sac tumor.

Extraneural metastases of intracranial germinomas, although infrequent, are associated with a generally poor prognosis despite the high radiosensitivity of localized primary tumors. Ventriculoperitoneal shunts have been implicated in facilitating metastatic spread of primary intracranial germinomas. We present a case of a successfully irradiated suprasellar germinoma recurring after 13 months as an intra-abdominal yolk-sac tumor in a young man. The tumor was eradicated with a combination of systemic chemotherapy and local irradiation, with no residual viable tumor cells confirmed at final surgical extirpation. The role of cerebrospinal fluid (CSF) shunts in metastases, mixed germ-cell tumor histology, and tumor markers in recurrences as well as radiation doses and volumes for treating primary tumors are discussed. Systemic chemotherapy may be utilized as prophylaxis against shunt metastases when CSF drainage is necessary.

Abdominal Neoplasms↗
PubMed1997

Triterpenoid saponins from Aster lingulatus.

Two new triterpenoid saponins named asterlingulatosides A and B were isolated from the whole plants of Aster lingulatus. Their structures were determined by spectroscopic data and chemical transformations to be 3-O-beta-D-glucopyranosyl-3 beta,16 alpha-dihydroxyolean-12-en-28-oic acid-28-O-alpha-L-O-arabinopyranoside and 3-O-beta-D-glucopyranosyl-3 beta,16 alpha-dihydroxyolean-12-en-28-oic acid-28-O-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranoside++ +. They showed inhibitory activity on DNA synthesis in human leukaemia HL-60 cells.

Antineoplastic Agents, Phytogenic↗
PubMed1997

Expression of cholecystokinin messenger RNA in reciprocally-connected auditory thalamus and cortex in the rat.

Cholecystokinin exerts a potent antiepileptic action in mammalian auditory system and undergoes seizure-mediated up-regulation. The present study investigated cholecystokinin messenger RNA expression in the reciprocally-connected auditory thalamus and cortex in the rat. Immunofluorescence in situ hybridization was performed using a 24-base cholecystokinin-messenger RNA oligonucleotide probe. Corticothalamic projection neurons were identified by means of the retrograde fluorescent tracer rhodamine latex microspheres injected into the medial geniculate body. In our experiments, cholecystokinin messenger RNA transcripts were found in about 80% of neurons located within the reciprocally-connected regions of the medial geniculate body and the auditory cortices. These observations provide evidence of cholecystokinin production in the reciprocally-connected regions of the auditory thalamus and cortex, the structures which jointly create the thalamo-corticothalamic circuit which has been implicated in seizure genesis.

Animals↗
PubMed1997

Effects of colony-stimulating factors (CSFs) on neutrophil apoptosis: possible roles at inflammation site.

We found that granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) had different effects on the apoptosis of human mature neutrophils induced by anti-Fas antibody. GM-CSF suppressed this process and neutrophils retained their functions of superoxide production and enzyme release against invasion of microorganisms. In contrast, G-CSF had a weaker effect on the anti-Fas antibody-induced neutrophil apoptosis than GM-CSF, with neutrophil function suppressed in proportion to the apoptosis. GM-CSF produced by satellite cells at the inflammatory site may inhibit apoptosis and the neutrophils may maintain their primed functions to kill the invading microorganisms. G-CSF produced by fibroblasts or endothelial cells may work in another fashion by increasing the number of neutrophils more effectively than GM-CSF. GM-CSF and G-CSF may exert different effects on neutrophils at the inflammatory sites in the human body.

Antibodies, Monoclonal↗