Biomedical subjects

X Ge

Publications and source records attributed to X Ge.

At least 73 records · Page 4Linked to original sources

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↗

PubMed1994

Endolymphatic hydrops associated with otosclerosis.

Endolymphatic hydrops (EH) associated with otosclerosis has been noted for many years. However, the causal relationship of these two entities remains controversial. Having reviewed the records of patients with otosclerosis describing fluctuant hearing loss and vertiginous symptoms, the authors found the EH may coexist with otosclerosis preoperatively; they may be two separate diseases that exist coincidentally; or EH may be caused by the otosclerotic process. Secondly, EH may occur with a fistula after surgery. Occurring after stapedectomy, EH may be caused by fistulization of the bony labyrinth, which is effectively treated by surgery to seal the fistula, which may cause EH to subside and hearing to improve. Thirdly, delayed EH may occur months or years after stapedectomy, possibly as a result of otosclerotic foci or surgical insult to the labyrinth. Dexamethasone, diuretics, and a room air rebreather can be used in the treatment of delayed EH. Hearing may be maintained or may deteriorate, but there usually is no dizziness. The clinical manifestations of EH associated with otosclerosis include a conductive or mixed type of hearing loss; the presence of fullness, tinnitus, fluctuation of hearing, episodic vertigo, an elevated negative summating potential (SP), and an increased summating potential:action potential (SP:AP) ratio shown by ECoG. This report presents five cases of EH associated with otosclerosis.

Adult↗

PubMed1994

Long-term results of low dose intramuscular streptomycin for Menière's disease.

The initial results of partial ablation of vestibular function are evident to control vertigo attacks and stabilize hearing as well as to reduce the severity of ataxia. The purpose of this study is to observe the long-term results of low dose intramuscular streptomycin in the treatment of bilateral Menière's disease. Eleven patients with disabling bilateral Menière's disease were treated with low doses of intramuscular streptomycin (20-40 g, mean = 25 g). Follow-up was 5-12 years (mean = 8 yr). All 11 patients achieved relief of their disabling vertigo. One patient had recurrent vertigo 1 year after treatment and streptomycin perfusion of the labyrinth was performed subsequently. Four patients reported feeling slightly off balance during follow-up. None experienced oscillopsia in this series. In the entire group of 11 patients (22 ears), hearing was unchanged in 17 ears, improved in two and worse in three. A hearing threshold of < 30 dB was found in two ears before and two after treatment; 30-60 dB was found in seven ears before and six after treatment; and > 60 dB was found in 13 ears before and 14 after treatment. The mean PTA of the 22 ears was 58 dB before and 65.5 dB after treatment. The mean speech discrimination scores were 61.4 percent before and 51.3 percent after treatment. The long-term results suggest that partial ablation of vestibular function by streptomycin has long-lasting effects of controlling vertigo attacks, stabilizing hearing, and reducing the severity of ataxia. Administration of low doses of intramuscular streptomycin is the treatment of choice for bilateral Menière's disease.

Adult↗

PubMed1993

trans-activation of the alpha 1-acid glycoprotein gene acute phase responsive element by multiple isoforms of C/EBP and glucocorticoid receptor.

alpha 1-Acid glycoprotein (AGP) is a major acute phase protein synthesized primarily by the liver. The AGP gene is transcriptionally activated in hepatocytes during the acute phase response to bacterial lipopolysaccharide. In this study, we analyzed an acute phase responsive element (APRE) located between nucleotide residues -127 to -104 relative to the transcription initiation site of the mouse AGP gene. Binding studies show that several trans-acting factors interact with the APRE. Using monospecific antibodies we demonstrate that three isoforms of the CCAAT/enhancer-binding protein (C/EBP) family, namely C/EBP alpha, C/EBP beta, and C/EBP delta, bind to the APRE. Furthermore, with liver nuclear protein from control animals, C/EPB alpha is the predominant form that binds to the APRE, whereas with nuclear proteins from acute phase-induced animals, C/EBP alpha is replaced by C/EBP beta. The mechanism of activation of the AGP gene during the acute phase response appears to involve an exchange of C/EBP alpha by C/EBP beta. C/EBP delta does not play a role in this reaction. Interestingly, the C/EBP binding site of the APRE partially overlaps a functional glucocorticoid responsive element. We present evidence that both purified C/EBP alpha and glucocorticoid receptor bind strongly to the APRE. By site-specific mutation, we have identified the C/EBP and glucocorticoid receptor binding sites in the APRE. These mutants were used in expression vectors to demonstrate that both C/EBP and glucocorticoid receptor are essential for maximal response to interleukin-6 and dexamethasone. These results demonstrate that the APRE is a composite binding site for multiple factors that are responsible for the transcriptional control of the mouse AGP. Finally, functional analyses indicate that C/EBP alpha, C/EBP beta, and C/EBP delta are strong transcriptional trans-activators of the AGP APRE in hepatoma cells. These data suggest that the regulatory activity of the C/EBP with the APRE in the liver may require interactions with adjacent proteins.

Acute-Phase Reaction↗

PubMed1993

Ossification patterns of the tympanic facial canal in the human fetus and neonate.

Dehiscences in the bony facial canal are comparatively common in the human adult. The highest incidence occurs in the tympanic segment of the facial nerve near the region of the oval window. Thirty-three fetal temporal bones, ranging from 16 to 40 weeks' gestation, and four from 1, 2, 4 and 12 weeks' postpartum neonates, were studied to evaluate the normal patterns of ossification of the fallopian canal of the tympanic facial nerve segment in the human. The tympanic facial nerve segment elongates three-fold during this period (from 1 mm to 3 mm). The ossification starts at 21 weeks' gestation anteriorly from apical otic ossification centers and at 26 weeks from canalicular ossification centers near the stapedius muscle. The ossification proceeds in an anterior-to-posterior direction as two periosteal shelves of bone surround the facial nerve. The superior periosteal bony ledge contributes 75% of the circumference of the fallopian canal. The anterior ossification center forms over 83% of the fallopian canal length. The two centers fuse post partum near the region of the oval window. The anatomic location of the facial nerve, nerve branching, and neural vasculature precede ossification. In 80% of the paired temporal bones, this ossification pattern appears to be symmetrical. The patterns and incidence of bony dehiscences within the tympanic fallopian canal segment can be explained by these observations. This study demonstrates that fallopian canal dehiscences are not congenital anomalies, but variations of normal developmental anatomic processes.

Cartilage↗