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Biomedical subjects

X Ge

Publications and source records attributed to X Ge.

89 records · Page 5Linked to original sources
PubMed1993

Factors influencing results with streptomycin perfusion of the labyrinth.

Streptomycin perfusion of the labyrinth is the logical choice of treatment for the third stage of Meniere's disease with intractable vertigo. The results of streptomycin perfusion of the labyrinth are comparable to those of other treatments, including endolymphatic shunt and vestibular nerve section. Refinements must be made in the process of selecting candidates for the operation. To study the factors influencing the results of streptomycin perfusion of the labyrinth, 144 patients who had streptomycin perfusion of the labyrinth and were followed for 1 year were studied using the 1972 AAOO classification of results. The findings of this study indicate that only a low dosage of streptomycin and a small volume of perfusate are required to obtain good results. Patients who have long lasting severe endolymphatic hydrops with poor hearing preoperatively are less likely to achieve good results.

Adult↗
PubMed1993

Transtympanic electrocochleography in Menière's disease using clicks and tone-bursts.

Transtympanic electrocochleography (ECoG), using clicks and tone-bursts at 500, 1000, and 2000 Hz, was employed to study 80 patients with Meniere's disease and 25 non-Meniere's patients. The magnitude of the negative summating potential and the summating potential:action potential ratio (SP:AP) were examined in both groups. Groups were further divided based upon degree of hearing loss and audiometric configuration. An elevated SP:AP ratio was found in 83.7 percent of the Meniere's ears and 12 percent of the non-Meniere's. The likelihood of obtaining a positive ECoG in Meniere's patients was strongly related to degree of hearing loss but not audiometric configuration.

Audiometry, Evoked Response↗
PubMed1993

Intramuscular streptomycin effect on dark cells of utricle in guinea pigs.

Streptomycin has been used in the treatment of Meniere's disease for almost half a century. Clinical studies showed that streptomycin may eliminate vertigo attacks and stabilize or improve hearing in the majority of patients. Animal experiments have demonstrated severe damage to the vestibular hair cells after streptomycin treatment. This study is to observe the effect of intramuscular streptomycin on dark cells of utricle. Guinea pigs that had received intramuscular injections of streptomycin sulfate 400 mg/kg per day for 1 and 2 weeks were studied. The dark cells of utricle were observed under transmission electron microscope. The pinocytotic vesicles and rough endoplasmic reticula markedly decreased and the plasmalemma infoldings in the lower part of the cell reduced in the 1-week group. The luminal membrane of the cells bulged out on the surface. After the cell membrane ruptured, the cytoplasmic organelle moved into the endolymphatic space and the cell dissolved. The morphologic changes indicated that streptomycin damaged the cytoplasmic granules and the plasma membrane infoldings of the dark cells. These cytologic characteristics are engaged in fluid secretion. The damage of secretory function of the dark cells may reduce the volume of endolymph.

Animals↗
PubMed1993

Husband and wife differences in response to undesirable life events.

In the present study of 451 married couples living in the rural midwest, gender differences were examined in reports of exposure and vulnerability to specific types of undesirable life events. Consistent with expectations derived from either a social structural or identity perspective, the results demonstrated that men are more likely than women to report exposure to and to be distressed by work and financial events. Women, on the other hand, are more strongly influenced by exposure to negative events within the family but not within their network of friends. Outcomes vary according to the type of emotional distress. Financial stress, for example, increases hostility among men more than among women, but wives are more likely than husbands to report somatic complaints in response to the same stressor. The findings demonstrate the need for future research that more directly investigates the intraindividual and social mechanisms which account for gender differences in a broad range of emotional and behavioral responses to varying types of significant life changes.

Adaptation, Psychological↗
PubMed1993

Effect on endocochlear potential of streptomycin perfusion of the cochlea in guinea pigs.

Perilymphatic perfusion of the cochlea with streptomycin was performed on 17 guinea pigs. The first and second group, consisting of five animals each, received streptomycin 150 micrograms and 1500 micrograms respectively. In a control group, consisting of seven animals, the perilymph was perfused with artificial perilymph only. The endocochlear potential (EP) was recorded from the second turn of the cochlea in each animal. The results indicate that streptomycin in a low dosage that will destroy the vestibular receptors was not harmful to the function of either the stria vascularis or the hair cells in the cochlea, as measured by changes in the EP after streptomycin perfusion of the cochlea.

Animals↗
PubMed1991

Functional analysis of the trans-acting factor binding sites of the mouse alpha-fetoprotein proximal promoter by site-directed mutagenesis.

The trans-acting factors of the mouse alpha-fetoprotein proximal promoter (-202 base pairs) are aligned as follows: regions Ia (HNF-1), Ib (C/EBP), II (NF-1 or C/EBP), II' (NF-1 or HNF-1), III (NP-III), IV (NP-IV), Va (NP-Va), and Vb (C/EBP). Site-specific mutation abolished protein binding to the corresponding mutated site with the exception of the NF-1 site, in which mutation causes partial protection. Transient expression analyses indicate that chloramphenicol acetyl-transferase (CAT) activity is reduced by mutations in regions Ia, II', Ib, II, and IV. Mutation of region III causes an increased activity and mutation of regions Va and Vb shows a slight inhibitory effect. Linking alpha-fetoprotein enhancer I to the wild type promoter resulted in a 12-fold stimulation of CAT activity. The activity of promoters with mutated C/EBP-binding sites (Ib, II, and Vb), was slightly above controls, indicating that enhancer I can reverse the effect of these mutations. Inhibition or stimulation of promoter activity resulting from mutations of the HNF-1 or NP-III binding sites, respectively, persisted when enhancer I was linked to the promoters, indicating that enhancer I cannot rescue these mutations. Mutation of both HNF-1-binding sites resulted in greater than 90% inhibition of CAT expression with and without enhancer I, indicating these sites are essential for promoter activity. The stimulation of promoter activity by mutation of the NP-III site suggests that this site may be essential for repression or attenuation of the alpha-fetoprotein gene. Our studies indicate that regulation of the alpha-fetoprotein gene requires the combinatorial effect of multiple cis- and trans-acting elements in the proximal promoter and that enhancer I may provide a factor(s) that specifically rescue the promoter from the inhibitory effect of mutation in the C/EBP-binding sites.

Animals↗
PubMed1991

Induction of several acute-phase protein genes by heavy metals: a new class of metal-responsive genes.

Acute-phase reactants, metallothioneins, and heat-shock proteins are the products of three families of genes that respond to glucocorticoids and cytokines. Metallothioneins and heat-shock proteins, however, are also stimulated by heavy metals, whereas very little is known about the effect of heavy metals on acute-phase-reactant genes. We have studied the effect of heavy metals (Hg, Cd, Pb, Cu, Ni, and Zn) and Mg on the acute-phase reactants alpha 1-acid glycoprotein, C-reactive protein, alpha 1-antitrypsin and alpha 1-antichymotrypsin. alpha 1-Acid glycoprotein and C-reactive protein mRNA levels were increased severalfold in livers of heavy-metal-treated Balb/c mice. The strongest induction was mediated by Hg, followed in order of response by Cd greater than Pb greater than Cu greater than Ni greater than Zn greater than Mg. None of the metals affected the mRNA levels of albumin, alpha 1-antitrypsin, and alpha 1-antichymotrypsin. Furthermore, failure to repress albumin, a negative acute-phase reactant, indicated that the induction of these genes was not due to a metal-mediated inflammatory response. The metals also induced alpha 1-acid glycoprotein and C-reactive protein in adrenalectomized animals, indicating that induction by the heavy metals is not mediated by the glucocorticoid induction pathway. Sequence analysis has revealed a region of homology to metal-responsive elements in the alpha 1-acid glycoprotein and C-reactive protein promoters. Additionally, an alpha 1-acid glycoprotein expression vector, pAGP(-595)CAT, responded to Hg and Cd when transfected into human HepG2 cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute-Phase Proteins↗
PubMed1991

[Streptomycin toxicity on dark cells of utricles in guinea pigs].

Thirty guinea pigs were divided into three groups. The first group received intramuscular injection of streptomycin sulfate 400 mg/kg/day for one week; the second group received the same dosage for two weeks; the third group served as the control. The cochlea was dissected after treatment and the utricle observed under electron microscope. The nystagmus lasted 11.3 sec. clockwise and 12.75 sec. counter-clockwise before treatment, 10.75 sec. and 9.25 sec. after one week and 6.0 sec. and 5.5 sec. after two weeks. Histopathologic study showed the normal dark cells in the control group. In the one week group, the dark cell remained in cuboidal shape. On the luminal surface of the cell were a few microvilli and invaginations which were in the process of forming pinocytotic vesicles. In the apical cytoplasm, the coated pinocytotic vesicles, vacuoles and rough endoplasmic reticula markedly decreased. The crest of mitochondria was blur, coalescent and vacuous. The plasmalemma in the lower part of the cell reduced. In the two-weeks group, the cells became squamous with less cytoplasm and organelle. There was no pinocytotic vesicles and vacuoles in the apical cytoplasm. The luminal membrane of the cells were bulging out into the cavity. In case the membrane ruptured, the cytoplasmic organelle run into the endolymphatic space and the cell dissolved and damaged. The morphological changes indicated that streptomycin damaged the cytoplasmic granules and the plasma membrane of dark cells. These cytologic characteristics of dark cells which engaged in the fluid transport were similar to those of the secretory cells in other organs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Short-term curative effect of cultured Cordyceps sinensis (Berk.) Sacc. Mycelia in chronic hepatitis B].

33 cases of chronic hepatitis B. patients treated with cultured Cordyceps sinensis mycelia have shown that the drug improves the liver function, promotes negative transfer HBsAg, and markedly helps to raise plasma albumin, resist high gamma globulin and to adjust body immunocompetence. It is therefore suggested that cultured Cordyceps sinensis mycelia may be used as a medicine for chronic hepatitis B. patients in adjusting protein metabolism and correcting inversion of albumin and globulin.

Albumins↗
PubMed1990

[Decompression of geniculate ganglion of facial nerve].

Decompression of geniculate ganglion of facial nerve in 20 cases of facial palsy caused by temporal bone fracture, herpes zoster otitic and Bell's palsy was reported. Sixteen cases had been followed up for half to four years. Complete recovery was observed in 13 cases and partial recovery in 3 cases. Transmastoid-attical approach was used. The geniculate ganglion and the distal part of the labyrinthine segment of the facial nerve could be exposed by this approach. The authors emphasized the importance of decompression of the geniculate ganglion, because of the anatomic characteristics and the pathologic features. The indications, the surgical approach and the precautions during operation were discussed.

Adolescent↗
PubMed1989

[The facial nerve in acoustic tumor surgery].

The results of facial nerve function in twenty-four cases of acoustic neuroma removal using translabyrinthine approach from 1982 to 1987 were reported. Facial nerve had been paralysed in one case preoperatively. The facial nerve function were preserved in 21 out of 23 cases (91.3%). The appearance of facial nerve during surgery was as follows: normally located in 9 cases, displaced and deformed in 12 cases and invaded by the tumor in 3 cases. The size and location of the tumor determine the chance of preservation of facial nerve function. The procedures of manipulating the facial nerve and preventing the injury to the facial nerve during surgery were discussed in detail.

Adolescent↗
PubMed1989

[Glycerol opening of blood-labyrinth barrier using electron-opaque tracer ferritin].

Fifteen guinea pigs were divided into three groups: the control, the ferritin and the glycerol-ferritin groups. In the first group, no any medication had been given; in the second group, ferritin 1 gm/kg was injected via the jugular vein; in the third group, 50% glycerol 3 ml/kg was injected 30, 60 and 120 minutes prior to the injection of ferritin. Striae were removed, fixed and embedded in Epon. Ultra-thin sections were cut and observed under electron microscope. No ferritin molecule was seen in the control group. In the ferritin group, the ferritin particles were seen in stria capillary only. In the glycerol-ferritin group, the ferritin molecules had entered the endothelial cells of stria capillary at 30 minutes. Ferritin molecules had got into stria vascularis and accumulated around the mitochondria at 60 minutes. The electron-opaque tracers had migrated to the apex of the marginal cells along microtubular system and permeated to the endolymphatic space through cell membranes and junctions. The ferritin particles appeared at the surface of marginal cells in the endolymphatic space at 120 minutes. The results indicate that glycerol can serve as an opener of blood-labyrinth barrier.

Animals↗
PubMedDate not supplied

The influence of neighborhood disadvantage, collective socialization, and parenting on African American children's affiliation with deviant peers.

This study focused on hypotheses about the contributions of neighborhood disadvantage, collective socialization, and parenting to African American children's affiliation with deviant peers. A total of 867 families living in Georgia and Iowa, each with a 10- to 12-year-old child, participated. Unique contributions to deviant peer affiliation were examined using a hierarchical linear model. Community disadvantage derived from census data had a significant positive effect on deviant peer affiliations. Nurturant/involved parenting and collective socialization processes were inversely associated, and harsh/inconsistent parenting was positively associated, with deviant peer affiliations. The effects of nurturant/involved parenting and collective socialization were most pronounced for children residing in the most disadvantaged neighborhoods.

Adolescent↗
PubMedDate not supplied

Induction of apoptosis in MCF-7 cells by indole-3-carbinol is independent of p53 and bax.

The anticancer activity of indole-3-carbinol and the possible mechanisms involved were explored in human breast cancer cell lines MCF-7 and T47D. Treatment with indole-3-carbinol suppressed the growth of MCF-7 and T47D cells. MCF-7 cells were more sensitive to indole-3-carbinol than T47D cells. The growth suppression caused by indole-3-carbinol was found to be partially involved in its ability to induce apoptosis (programmed cell death) in MCF-7 cells. Western blot analysis demonstrated that wild-type p53 was not induced after treatment of MCF-7 cells with indole-3-carbinol. Northern blot analysis showed that treatment of MCF-7 cells with indole-3-carbinol did not affect the expression of bax gene (one of the death genes). In the tissue culture medium, indole-3-carbinol was found to be partially converted to 3,3'-diindolylmethane. The experiments indicated that indole-3-carbinol suppressed MCF-7 cell growth in part by induction of apoptosis which was independent of p53 and bax expression and that the effect caused by indole-3-carbinol was partially due to its conversion to a more potent compound, 3,3'-diindolylmethane, in vitro.

Apoptosis↗