Biomedical subjects

X Ge

Publications and source records attributed to X Ge.

At least 55 records · Page 3Linked to original sources

PubMed1996

3,3'-Diindolylmethane induces apoptosis in human cancer cells.

3,3'-Diindolylmethane is a dimer of indole-3-carbinol formed both in vivo and in vitro. In this study, human cancer cells MCF-7 (with wild-type p53), T47-D (mutant p53), and Saos-2 (deficient in p53 gene), were used to examine the anticancer activities of 3,3'-diindolylmethane. The dose-dependent growth inhibitory effect was found in all these cell lines. Exposure of the cells to 50 microM solution of 3,3'-diindolylmethane for 48 h, apoptosis (programmed cell death) was evidenced by the characteristic morphology of cell nuclei under fluorescence microscope and the DNA "ladder" in agarose gel electrophoresis. The percentage of apoptotic cells in each cell line was found to be 12% for MCF-7, 14% for T47D and 13% for Saos2 cells. Exposure of MCF-7 cells to 100 microM 3,3'-diindolylmethane for 24 h, 19% of apoptotic cells were detected by flow cytometry analysis. The lowest dose required for induction of apoptosis in MCF-7 cells was found to be 10 microM after 72 h incubation. Western blot showed that wild-type p53 protein was unchanged after MCF-7 cells had been exposed to 50 microM 3,3'-diindolylmethane for 8 h. This study provides evidences that 3,3'-diindolylmethane induces apoptosis in human cancer cells and that the induction of apoptosis is independent of p53 pathway.

Anticarcinogenic Agents↗

PubMed1996

A plant viral coat protein RNA binding consensus sequence contains a crucial arginine.

A defining feature of alfalfa mosaic virus (AMV) and ilarviruses [type virus: tobacco streak virus (TSV)] is that, in addition to genomic RNAs, viral coat protein is required to establish infection in plants. AMV and TSV coat proteins, which share little primary amino acid sequence identity, are functionally interchangeable in RNA binding and initiation of infection. The lysine-rich amino-terminal RNA binding domain of the AMV coat protein lacks previously identified RNA binding motifs. Here, the AMV coat protein RNA binding domain is shown to contain a single arginine whose specific side chain and position are crucial for RNA binding. In addition, the putative RNA binding domain of two ilarvirus coat proteins, TSV and citrus variegation virus, is identified and also shown to contain a crucial arginine. AMV and ilarvirus coat protein sequence alignment centering on the key arginine revealed a new RNA binding consensus sequence. This consensus may explain in part why heterologous viral RNA-coat protein mixtures are infectious.

Alfalfa mosaic virus↗

PubMed1996

The nucleotide sequence of hydrangea mosaic virus RNA 3 exhibits similarity with the RNA 3 of tobacco streak virus.

The complete nucleotide sequence of the RNA 3 of hydrangea mosaic virus (HdMV) was determined. It consists of 2268 nucleotides and contains two open reading frames (ORF). ORF 1 encodes for a putative translation product of 293 amino acids which shared 64.9% identity with the 3a protein of tobacco streak virus (TSV). ORF 2 encodes for a putative translation product of 220 amino acids which shared 54.2% identity with the coat protein of TSV. The relationship between the proteins of HdMV and the corresponding proteins of ilarviruses other than TSV was more distant. No zinc-finger-like motif was found in the coat protein of HdMV but the N-terminus of the protein was rich in basic amino acids. Both terminal, non-coding regions of HdMV RNA 3 contained repeated sequences with corresponding homologous fragments in the RNA 3 of TSV. On the basis of the similarities between HdMV and TSV that we detected, we propose that HdMV be included in subgroup 1 of the genus Ilarvirus together with TSV.

Amino Acid Sequence↗

PubMed1996

An eight-nucleotide sequence in the potato virus X 3' untranslated region is required for both host protein binding and viral multiplication.

Gel retardation and UV-cross-linking techniques were used to demonstrate that two tobacco proteins, with approximate molecular masses of 28 and 32 kDa, bind to a site within the 3' region of potato virus X (PVX) genomic RNA. The protein binding is specific, in that a 50-fold excess of unlabeled probe prevents formation of the complexes but no reduction is observed with a 2,000-fold molar excess of yeast tRNA. Complex formation is inhibited by poly(U) but is relatively unaffected by poly(A), poly(G), or poly(C-I). PVX RNA-host protein complex formation occurs in vitro at salt concentrations up to 400 mM. Deletion mapping indicates that the proteins bind within the 3' untranslated region (UTR) of PVX genomic RNA and that an 8-nucleotide U-rich sequence (5'-UAUUUUCU) is required for the binding. Deletion of the 8-nucleotide U-rich region from the 3' UTR of a sensitive PVX reporter virus that carries the luciferase gene in place of the PVX coat protein gene results in a more than 70,000-fold reduction in luciferase expression in tobacco protoplasts. RNA probes carrying the sequence GCGC in place of the central four contiguous uridines of the 8-nucleotide U-rich motif fail to bind host protein at detectable levels, and the same mutation, when introduced into the PVX reporter virus, eliminates viral multiplication. Mutations of 1 or 2 nucleotides within the same four uridines reduced both binding of host proteins and replication of reporter virus. These results indicate that the 8-nucleotide U-rich motif within the PVX 3' UTR is important for some aspect of viral multiplication and suggest that host protein binding plays a role in the process.

Gene Deletion↗

PubMed1996

Different methylation patterns of the M-BCR gene in myeloblastic and lymphoblastic crisis of chronic myelocytic leukemia.

OBJECTIVE: To investigate the relationship between methylation status of M-bcr gene and transformation of chronic myelocytic leukemia (CML) from chronic to blastic phase. MATERIAL AND METHODS: The methylation patterns of M-bcr in 23 patients with Ph' positive CML were studied. DNAs extracted from mononuclear cells of both chronic and blastic phases (20 cases) or blastic phases only (3 cases), were doubly digested with restriction enzymes HpaII and BglII, hybridized with a 5'M-bcr probe labeled with 32p-deoxycytidine triphosphate, and autoradiographed. RESULTS: In all the patients with myeloblastic crisis, DNAs from both chronic and blastic cells of each patient showed identical methylation patterns. There was substantial heterogeneity in methylation patterns in the patients with lymphoblastic crisis. All the lymphoblastic patterns were distinct from the chronic patterns as well as the patterns shown in myeloblastic crisis. Moreover, in four out of six patients with lymphoblastic crisis, the chronic patterns were different from those in cases with myeloblastic crisis. CONCLUSIONS: The methylation status of M-bcr was stable during evolution of CML from chronic to myeloblastic phase. Analysis of M-bcr methylation status may be of clinical use in distinguishing lymphoblastic from myeloblastic crisis and predicting the cell lineage of crisis when the disease is still in its chronic phase.

Blast Crisis↗

PubMed1996

Dexamethasone perfusion of the labyrinth plus intravenous dexamethasone for Ménière's disease.

Recent clinical and laboratory evidence indicates that Meniere's disease is an immune-mediated disease. Dexamethasone perfusion of the inner ear through the round window plus intravenous dexamethasone often will stop the dizzy spells, reduce the fullness and low-frequency tinnitus, and sometimes improve the hearing in patients with Meniere's disease. The dexamethasone must act mostly on the endolymphatic sac and, to a lesser extent, on the stria vascularis and spiral ligament, the known targets of immune response in the inner ear, to reduce the endolymphatic hydrops and restore the fluid dynamics of the endolymph. Despite the good results with streptomycin perfusion, the number of patients with further hearing loss is large, so dexamethasone perfusion with intravenous dexamethasone should be tried first. The initial response to dexamethasone perfusion plus intravenous dexamethasone has been very good, with very little risk of further hearing loss, and it holds great promise for the future.

Administration, Topical↗

PubMed1996

Coming of age too early: pubertal influences on girls' vulnerability to psychological distress.

This 4-year longitudinal study investigates 3 hypothesized effects of the pubertal transition on the psychological distress of adolescent girls (N = ca. 200): early maturation, the impact of heterosexual versus same-sex friends, and prepubertal vulnerabilities, such as early emotional distress and father hostility. Building on Caspi and Moffitt's study of girls' delinquency, this study found that early maturing girls experienced significantly higher levels of psychological distress compared to their on-time and late maturing age-mates. In line with prior studies of girls' delinquency (Caspi, Lynam, Moffitt, & Silva, 1993; Magnusson, 1988), early maturing girls also experienced higher levels of distress at the tenth grade as reported by fathers, mothers, and adolescents when they were associated with mixed- rather than same-sex friends during the seventh through ninth grades. Finally, early maturing girls were more vulnerable to prior psychological problems, deviant peer pressures, and fathers' hostile feelings when compared to on-time and late maturing peers.

Adolescent↗

PubMed1995

The nucleotide sequence of citrus leaf rugose virus RNA 1.

The nucleotide sequence of citrus leaf rugose virus (CiLRV) RNA 1 consists of 3404 nucleotides and contains one open reading frame (ORF) which encodes a putative translation product of 1051 amino acids with a calculated M(r) of 118339. Both the nucleotide sequence of CiLRV RNA 1 and its translated polypeptide share similarities with those of the RNA 1 of alfalfa mosaic virus. However, the relationship is not as close as that which exists between the polymerase signatures of the two viruses, which are found on RNA 2. This is the first report of the full-length sequence for the RNA 1 of an ilarvirus and completes the first sequence for an entire ilarvirus genome. If it is typical of members of the genus then, as has long been speculated, the genomic organization of ilarviruses is identical to that of other genera in the family Bromoviridae.

Amino Acid Sequence↗

PubMed1995

The complete nucleotide sequence of RNA 3 of citrus leaf rugose and citrus variegation ilarviruses.

Complete sequence data for the RNA 3 of both citrus leaf rugose (CiLRV) and citrus variegation (CVV) ilarviruses have been determined. The RNAs are 2289 nt (CiLRV) and 2309 nt (CVV) in length and both contain the typical Bromoviridae arrangement of two open reading frames (ORFs) which, when translated, code for proteins that correspond to the Mr 32,000 (32K) putative movement proteins (ORF 1) and the coat proteins (ORF 2) of the respective viruses. The 3' termini of both viruses can be folded to form a secondary structure similar to those reported for other ilarviruses. These are the first complete nucleotide sequences for RNA 3 of members of subgroup 2 of the ilarviruses. The two viruses share substantial homology in nucleic acid sequence, code for identically sized coat proteins and share high levels of identity in the translated products of both ORFs. Although related, these viruses differ sufficiently to be considered distinct. The RNA 3s of CiLRV and CVV appear to be distinct from those of other ilarviruses for which comparable sequence data are available and also from the closely related alfalfa mosaic virus.

Amino Acid Sequence↗

PubMed1995

The complete nucleotide sequence of the RNA 3 of lilac ring mottle ilarvirus.

The nucleotide sequence of lilac ring mottle ilarvirus (LRMV) RNA 3 consists of 2287 nucleotides and contains two open reading frames (ORF). The first encodes a putative translation product of 285 amino acids (Mr 31 308) and the second encodes a putative translation product of 206 amino acids (Mr 22751). The 3' terminal nucleotides can be folded into a loop structure similar to models proposed for other ilarviruses, although the last four nucleotides are UCGC not AUGC. The absence of the terminal AUGC motif in both LRMV and two isolates of apple mosaic ilarvirus (ApMV) provides circumstantial evidence which confirms the importance of AUGC motifs upstream of the terminal AUGC in the protein binding function associated with these models. Although the 3' terminal structure of LRMV exhibits similarities to that of ApMV, comparison of the putative translation products of the two ORFs with similar products for other ilarviruses showed greatest identity with citrus leaf rugose (CiLRV) and citrus variegation (CVV) ilarviruses both of which are members of subgroup 2 of this genus. Thus it is proposed that LRMV be reassigned to subgroup 2 rather than remaining in its current subgroup, 7, or being reassigned to subgroup 3 which contains ApMV.

Amino Acid Sequence↗

PubMed1995

It takes two to replicate: a mediational model for the impact of parents' stress on adolescent adjustment.

In this study of parental stress and adolescent adjustment, experiences of negative life events during the recent past were used to generate a measure of acute stress. In addition, multiple indicators based on reports from various informants were used to estimate latent constructs for parental depression, discipline practices, and adolescent adjustment. Employing 2 independent samples of families from 2 different regions of the country (rural Iowa and a medium-sized city in Oregon), structural equation models were used to test the hypothesis that in intact families acute stress experienced by parents is linked to boys' adjustment (average age equaled 11.8 years in the Oregon sample, 12.7 years in the Iowa sample) through 2 different causal mechanisms. The findings showed that parental stress was related to adjustment through stress-related parental depression that is, in turn, correlated with disrupted discipline practices. Poor discipline appears to provide the direct link with developmental outcomes. The structural equation model (SEM) used to test the proposed mediational process was consistent with the data for mothers and boys from both the Oregon and the Iowa samples. The similarity in results was less clear for fathers and boys. Implications of these results for future replication studies are discussed.

Adaptation, Psychological↗

PubMed1995

Middle ear and inner ear effects on clinical bone-conduction threshold.

The measurement of bone-conduction thresholds is an integral part of audiologic evaluation. The relationship between bone-conduction and air-conduction thresholds is the differentiating diagnostic indicator between conductive and sensorineural hearing loss. At the same time, the influence of middle ear and inner ear structures upon the bone-conduction response has been well documented. We present two cases illustrating this influence and attempt to explain the clinical bone-conduction thresholds with operative findings.

Acoustic Impedance Tests↗

PubMed1995

Scanning electron microscopic observation of dark cells after streptomycin perfusion of the vestibule in guinea pigs.

Hearing has been stabilized in the majority of patients studied in the treatment of Meniére's disease with streptomycin. This observation suggests that effects of streptomycin may ameliorate endolymphatic hydrops, possibly by attenuating the activity of secretory tissue. The purpose of this study is to observe the dark cells of the utricle in guinea pigs after streptomycin perfusion of the vestibule. Twelve pigmented guinea pigs weighing 250-350 grams were used in this study. The vestibules in five guinea pigs were perfused monolaterally with 150 micrograms of streptomycin in artificial perilymph and, in seven, the vestibules were perfused only with artificial perilymph as a control group. Specimens were processed for observation with a scanning electron microscope. After streptomycin perfusion, the margin of the dark cells became indistinct. The luminal surface of the cells bulged out like a dome. The microvilli decreased or were absent, and some debris was deposited on the surface. In four of the five animals, the luminal membrane of the dark cell ruptured. The cytoplasm and organelle extruded into the endolymphatic space. After the cellular debris moved out into the endolymph, either a vanished cell or a nucleus in an empty nest was observed. These cells appeared damaged and destroyed. The results indicate that the dark cells in the membranous wall of the utricle were affected by streptomycin. The results lead to the assumption that streptomycin may reduce the volume of endolymph by damaging the dark cells of the utricle.

Animals↗

PubMed1995

Traumatic endolymphatic hydrops.

Traumatic endolymphatic hydrops is an accumulation of endolymph in the cochlear duct caused by traumatic insult. The causative mechanisms are: (1) fistulization of the bony labyrinth, which causes a disturbance in the normal perilymph-endolymph pressure relationship; (2) direct injury to the membranous labyrinth, which may be just a collection of fluid in the cochlear duct from irritation, resulting in endolymphatic hydrops that may not be progressive and may subside in a short period of time after injury and hearing loss may occur; and (3) injury to the endolymphatic fluid drainage system, including a temporal bone fracture in which the fissure happens to extend through the vestibular aqueduct, causing fibro-osseous blockage of the endolymphatic duct and surgical injury to the saccule with obstruction of the longitudinal flow of endolymph, resulting in endolymphatic hydrops that may be delayed in onset and is usually persistent. The diagnosis of traumatic endolymphatic hydrops is made by a history of trauma, such as barotrauma, a blow to the head, or perhaps a previous ear operation, such as stapedectomy; the presence of typical symptoms of endolymphatic hydrops, including fullness, tinnitus, fluctuant hearing loss, and episodic vertigo; and an elevated negative summating potential and an increased summating potential:action potential ratio by electrocochleography. Three patients are presented to demonstrate this clinical entity.

Adult↗

PubMed1994

The nucleotide sequence of citrus leaf rugose ilarvirus RNA-2.

The nucleotide sequence of citrus leaf rugose ilarvirus (CiLRV) RNA-2 consists of 2990 nucleotides and contains one open reading frame (ORF) which encodes a deduced translation product of 832 amino acids with a calculated M(r) of 95,501 (95K). The 5' terminus of the RNA has a m7Gppp cap. Both the nucleotide sequence of CiLRV RNA-2 and its translated polypeptide share homologies with the nucleotide sequence and translated polypeptide, respectively, of RNA-2 of alfalfa mosaic virus (AlMV). The homology occurs in the central region of both the nucleic acid sequence and the polypeptide. Homologies between either CiLRV or AlMV and other Bromoviridae (cucumber mosaic virus--CMV, brome mosaic virus--BMV and cowpea chlorotic mottle virus--CCMV) were far less. Alignment of the 104 amino acid region (polymerase signature) of the 95K protein against 10 other 'alpha-like' plant viral polymerase signatures showed that CiLRV and AlMV are more closely related to each other than to CMV, BMV or CCMV. This is the first report of the full-length sequence of RNA-2 of an ilarvirus.

Amino Acid Sequence↗

PubMed1994

Economic stress, coercive family process, and developmental problems of adolescents.

We propose a model of family conflict and coercion that links economic stress in family life to adolescent symptoms of internalizing and externalizing emotions and behaviors. The 180 boys and 198 girls in the study were living in intact families in the rural Midwest, an area characterized by economic decline and uncertainty. Theoretical constructs in the model were measured using both trained observer and family member reports. These adolescents and their parents were interviewed each year for 3 years during the seventh, eighth, and ninth grades. Our theoretical model proposes that economic pressure experienced by parents increases parental dysphoria and marital conflict as well as conflicts between parents and children over money. High levels of spousal irritability, coupled with coercive exchanges over money matters, were expected to be associated with greater hostility in general by parents toward their children. These hostile/coercive exchanges were expected to increase the likelihood of adolescent emotional and behavioral problems. Overall, results were consistent with the proposed model. Moreover, the hypothesized processes applied equally well to the behavior of mothers and fathers, as well as sons and daughters.

Acting Out↗

PubMed1994

Parents' stressful life events and adolescent depressed mood.

The present study of 451 families living in the rural Midwest examines a mediational model of the relationship between the stressful life events experienced by parents and adolescent depressed mood. This model is intended to overcome two limitations in previous research on the relationship between parents' stressful events and adolescent depressed mood by 1) examining a mediating process involving parental mood and parenting behavior, and 2) using multiple informants to assess the theoretical constructs. Findings from the present study indicate that stressful life events experienced by parents are first related to parents' depressed mood which operates to disrupt skillful parenting practices. The disrupted parenting practices in turn place adolescents at increased risk for developing depressive symptoms. The results show that inclusion of these mediating processes represents a significant improvement over the bivariate model and that the hypothesized mediational model generalizes to four parent-adolescent dyads: fathers and sons, fathers and daughters, mothers and sons, and mothers and daughters. Moreover, parents' stressful life events are related directly to adolescent boys' depressed mood only when parents' reports are included in both theoretical constructs. When parents' reports are removed as an indicator for the adolescent depressed mood construct, the effects of parental stress on adolescent depressed mood are largely accounted for by stress-related parental depressed mood and harsh/inconsistent parenting.

Adolescent↗

PubMed1994

Streptomycin perfusion of the labyrinth through the round window plus intravenous streptomycin.

Streptomycin perfusion of the labyrinth through the round window membrane in the middle ear is a simple, safe, and effective way to stop the dizzy spells, fullness, and tinnitus of Ménière's disease without making the hearing worse. My results with 24 patients in the last 8 months are presented. Although the long-term effect of this operation remains to be seen, my experience with streptomycin perfusion of the labyrinth through the lateral semicircular canal leads me to believe these good results will be maintained in the future. Although the caloric response is not usually eliminated completely in the operated ear, it is reduced enough that the patient no longer has dizzy spells. Because the vestibular receptors are not completely destroyed, and the afferent and efferent nerves coming to and from them are undamaged, the patient compensates after this operation more quickly than when the vestibular receptors are completely destroyed by intramuscular or middle ear aminoglycoside, or when the afferent and efferent nerves of the vestibular receptors are cut as in labyrinthectomy or vestibular neurectomy. Hyaluronan is used to carry the streptomycin into the inner ear because it is known to penetrate the round window easily, and because being hygroscopic, it may reduce the amount of endolymph by osmosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Ear, Inner↗