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Biomedical subjects

W Yang

Publications and source records attributed to W Yang.

At least 469 records · Page 26Linked to original sources
PubMed1995

Modulation of tRNA(iMet), eIF-2, and eIF-2B expression shows that GCN4 translation is inversely coupled to the level of eIF-2.GTP.Met-tRNA(iMet) ternary complexes.

To understand how phosphorylation of eukaryotic translation initiation factor (eIF)-2 alpha in Saccharomyces cerevisiae stimulates GCN4 mRNA translation while at the same time inhibiting general translation initiation, we examined the effects of altering the gene dosage of initiator tRNA(Met), eIF-2, and the guanine nucleotide exchange factor for eIF-2, eIF-2B. Overexpression of all three subunits of eIF-2 or all five subunits of eIF-2B suppressed the effects of eIF-2 alpha hyperphosphorylation on both GCN4-specific and general translation initiation. Consistent with eIF-2 functioning in translation as part of a ternary complex composed of eIF-2, GTP, and Met-tRNA(iMet), reduced gene dosage of initiator tRNA(Met) mimicked phosphorylation of eIF-2 alpha and stimulated GCN4 translation. In addition, overexpression of a combination of eIF-2 and tRNA(iMet) suppressed the growth-inhibitory effects of eIF-2 hyperphosphorylation more effectively than an increase in the level of either component of the ternary complex alone. These results provide in vivo evidence that phosphorylation of eIF-2 alpha reduces the activities of both eIF-2 and eIF-2B and that the eIF-2.GTP. Met-tRNA(iMet) ternary complex is the principal component limiting translation in cells when eIF-2 alpha is phosphorylated on serine 51. Analysis of eIF-2 alpha phosphorylation in the eIF-2-overexpressing strain also provides in vivo evidence that phosphorylated eIF-2 acts as a competitive inhibitor of eIF-2B rather than forming an excessively stable inactive complex. Finally, our results demonstrate that the concentration of eIF-2-GTP. Met-tRNA(iMet) ternary complexes is the cardinal parameter determining the site of reinitiation on GCN4 mRNA and support the idea that reinitiation at GCN4 is inversely related to the concentration of ternary complexes in the cell.

Binding, Competitive↗
PubMed1995

[Dynamec changls in dimension of cross-sectional areas of lumbar canal and dural sac: an experimental study].

The variation in the cross-sectional areas (CSA) of lumbar canal and dural sac under extension and flexion was studied by using CT scans in ten human cadaver lumbar spine specimens. CSA at different levels or same level in varying positions were distinctive. CSA in flexion position was increased, while in extension position reduced. Dynamic changes of CSA of canal (CSAC) at L4,5,L5-S1 were very significant (P < 0.01), and those of CSA of dural a (CSADS) at all levels but L5-S1 were significant (P < 0.05). It was considered that dynamic changes of CSAC at intervertebral levels were determined by the range of lumbar motions, but those of CSADS were influenced by changes of canal and biomechanical factors of intracanal soft-tissue and changes of dural sac length. Measurement of CSADS was more significant than that of CSAC.

Adolescent↗
PubMed1995

[Evaluation of the effects of intermittent iron supplement on iron-deficiency anemia in children].

A three-month iron supplement trial was conducted in 238 preschool children, who were divided randomly into three groups supplemented with oral administration of iron preparation at the same dose everyday, every other two days, and each week, respectively, to avoid low-absorption and side-effects of oral iron preparation and to evaluate its preventive and treatment effects and side-effects. Results showed individual iron-supplement by once every other two days or each week was efficient as same as by once everyday in improving anemia and increasing serum ferritin level. It can also reduce transient iron overload and gastrointestinal side-effects caused by daily iron supplement.

Anemia, Iron-Deficiency↗
PubMed1995

Large-scale spraying of bednets to control mosquito vectors and malaria in Sichuan, China.

Since 1987, up to 2.42 million bednets owned by rural householders in over 40 counties in seven prefectures of Sichuan Province, China, have been sprayed annually with deltamethrin at a dose of about 10 mg/m2. Data for the years 1987-89 indicate that there were marked reductions in the biting populations and survival of the two vector species Anopheles anthropophagus and A. sinensis. Extensive tests in 1992 in areas where bednet spraying had been carried out for 5 years showed that mortality was 100% with the WHO-recommended discriminating dose of deltamethrin, i.e., there was no indication of resistance. Malaria data obtained by passive surveillance of reported cases, mass blood surveys of schoolchildren, and active surveillance of reported blood slides from fever cases all indicated marked reductions after introduction of the net spraying. In contrast, in the control areas, where the nets were not treated, the situation remained static or deteriorated slightly.

Animals↗
PubMed1995

[Study on treatment of absence of the oval window].

From March 1983 to June 1991 ten cases (twelve ears) underwent middle ear exploration for severe conductive hearing loss. Absence of oval window was found. Vestibulotomy and reconstruction of the ossicular chain were performed. Among patients with horizontal segments of the facial nerve displaced downward over the oval window region, or those after operation the inital gain of the hearing gradually reduced as a result of ablitecation of new fenestra, fenstration operation on the horizontal semicircular canal was performed. Vestibulotomy (10 ears) had resulted in elevated spech reception thresholds of 10-30 dB or more in 7 ears. Four of these patients had initial gain of the hearing reduced after 3 months. Fenestration in four cases resulted in elevated SRT of 20-45 dB. So fenestration is preferred. The authors have also presented their experience in the management of absence of the oval window.

Adolescent↗
PubMed1995

Fragile X gene instability: anchoring AGGs and linked microsatellites.

Interspersed AGGs within the FMR1 gene CGG repeat region may anchor the sequence and prevent slippage during replication. In order to detect the AGG position variations, we developed a method employing partial MnlI restriction analysis and analyzed X chromosomes from 187 males, including 133 normal controls (117 with 20-34 and 16 with 35-52 repeats), plus 54 fragile X premutations with 56-180 repeats. Among controls, the interspersed AGG positions were highly polymorphic, with a heterozygosity of 91%. Among the control samples, 1.5% had no AGG positions, 25% had one, 71% had two, and 3% had three. Among the fragile X premutation samples, 63% had no AGG, while 37% had only one AGG. Analysis of premutation samples within fragile X families showed that variation occurred only within the 3' end of the region. Thus, the instability was polar. Controls with > or = 15 pure CGG repeats were associated with the longest alleles of two nearby microsatellites, FRAXAC1 with 20-21 repeats and DXS548 with 202-206 bp and with increased microsatellite heterozygosity. The association of long pure CGG regions, as with fragile X chromosomes, with the longer and more heterozygous microsatellite alleles suggests they may be related mechanistically. Further, our results do not support a recent suggestion that the frequency of fragile X alleles may be increasing. Finally, analysis of a set of nonhuman primate samples showed that long pure CGG tracks are variable in size and are located within the 3' region, which suggests that polar instability within FMR1 is evolutionarily quite old.

Alleles↗
PubMed1995

[Baseline hypertriglyceridemia, a risk factor for non-insulin dependent diabetes mellitus: a 6-year follow-up study of 432 nondiabetics].

The relationship between baseline fasting plasma triglycerides level (FTG) and the incidence of non-insulin-dependent diabetes mellitus (NIDDM) within 6 years were investigated in 432 Chinese nondiabetics. They were identified by oral glucose tolerance test (OGTT, oral 75 g glucose) in Daqing diabetes survey in 1986. 220 subjects were men and 212 women. Among them 226 had normal glucose tolerance and 206 impaired glucose tolerance. The measurement of fasting plasma lipids and glucose were performed at the baseline examination and after 6-year follow-up. Six-year incidence of NIDDM in the highest triglycerides tertile group (top tertile Q3, mean = 2.5 mmol/L) was 2.3 times (38.6% vs 16.6%, P < 0.01) as compared with that of the lowest triglycerides tertile group (first tertile Q1, mean = 0.7 mmol/L). The difference of 2-hour blood glucose level in OGTT (OGTT BG2h level) between Q1 and Q3 was 2.4 mmol/L (mean = 7.6-10.0 mmol/L) after 6 years. Multivariate general linear regression analysis demonstrated that the FTG level was positively associated with the OGTT BG2h level after 6 years (P = 0.0335) after controlling the age, sex, fasting blood glucose (FBG) and body mass index (BMI). Therefore this result indicates that FTG level is an independent risk factor for the development of NIDDM in this population.

Adult↗
PubMed1995

[Anaesthesia for esophageal reconstruction with abdominal viscera in non-thoracotomy].

Radical resection of carcinoma of the hyopharynx and cervical esophagus usually involves pharyngolaryngo-esophagectomy and esophaged reconstruction with stomach or colonic replacement. From 1983 to 1994, 139 patients underwent the operations in our hospital. Although no thoracotomy, the extensive involvement of the neck, thorax and abdomen in the operation made the anesthesia difficult. There were 66 patients whose blood pressure dropped more than 3 kPa in the course of trans-mediastinum extraction of esophagus and gastric pull-up. There were injury of posterior wall of trachea in 2 patients and spleen rupture in 3. However, no anesthetic complications occurred during the operation.

Adult↗
PubMed1995

[Ultracytochemical observation of secretory cells and surfactant-like lamellar bodies in mucosa of eustachian tube].

The distribution of secretory cells and surfactant-like lamellar bodies in mucosa of the guinea pig eustachian tube were studied ultracytochemically. Classified by means of their morphologic characteristics, three types of secretory cells were identified. The dark granulated cells were predominant in the tympanic orifice, the mixed cells were predominant in the isthmus portion, while the light cells were predominant in the pharyngeal orifice. The distribution of the secretory cells in different part of the eustachian tube might play a role in the pathogenesis of middle ear effusions. Surfactant-like lamellar bodies were found in ciliated cells, nonciliated cells and secretory cells of the eustachian tube mucosa. Surfactant-like lamellar bodies (surfactant-like substance) are important in maintaining the physiological function of the eustachian tube, their behavior in normal and pathological states should be further studied.

Animals↗
PubMed1995

[Peribulbar anesthesia and intraocular lens implantation].

We studied the effectiveness of peribulbar anesthesia in 146 patients undergoing cataract surgery and intraocular lens implantation. The results revealed that the analgesic and akinetic effects obtained from peribulbar anesthesia are the same as or even better than that obtained from retrobulbar anesthesia. In the mean time, the use of peribulbar injection can avoid or reduce the serious complications associated with the retrobulbar injection. In this report, the method of peribulbar anesthesia was introduced and its mechanisms and effectiveness were discussed. The pre- and post-anesthetic intraocular pressures were especially observed and compared. It is safe to perform the operation 10 minutes after the administration of the peribulbar anesthesia.

Adolescent↗
PubMed1995

Primary posterior chamber intraocular lens implantation in traumatic cataract with posterior capsule breaks.

BACKGROUND: In patients with incomplete posterior capsule support, posterior chamber intraocular lenses (PC-IOLs) were implanted with both haptics transscleral fixation. This causes more damage to the eye and may result in more complications. In patients with small posterior breaks, non-fixation or single haptic fixation may be adequate. METHODS: Thirty-two consecutive patients of traumatic cataract with posterior capsule breaks caused by penetrating eye trauma were retrospected. Posterior chamber intraocular lenses were implanted in all these patients with three techniques, ie, without fixation, with single haptic fixation and with both haptics fixation. The selection of the technique was based on the position and size of the posterior capsule. The follow-up period was 21 days to 28 months (mean, 15.2 months). RESULTS: Intra-operative problems included ciliary body bleeding (two patients, 6.25%) and enlargement of posterior capsule breaks (2 patients, 6.25%). Postoperative visual acuity was 0.5 or better (corrected) in 28 case (87.5%) and 0.1-0.4 in four patients (12.5%). Postoperative complications included hyphema (6 eyes, 18.8%), transient intraocular pressure elevation (6 eyes, 18.8%), transient hypotention (7 eyes, 21.8%). Postoperative IOL position were good except one case of IOL tilt. No pupillary capture or endophthalmitis was found. CONCLUSIONS: Not all PC-IOLs have to be fixed by two haptics. In patients with small posterior capsule breaks, PC-IOL may not be fixed or fixed by only one haptics.

Adolescent↗
PubMed1995

[Early diagnosis of acoustic neuroma].

The diagnostic findings in 31 patients (32 ears) with acoustic neuromas are reported. In patients suspicious of acoustic neuroma, case history and clinical examination are important. In our material of 31 patients with acoustic neuromas, hearing loss was presented in 94% (slow onset 87%, sudden onset 10% and fluctuating 3%), tinnitus in 91%, vestibular symptoms (dizziness or vertigo) in 62%. It should be stressed that in patients with unilateral hearing loss (or tinnitus) or vestibular symptoms, it is necessary to exclude the presence of an acoustic neuroma. In addition, the trigeminal never was affected in 34%, which was encountered in tumours larger than 26-40 mm. There was a positive correlation between duration of symptoms and size of the tumour, but there was no correlation between hearing loss and size of the tumour. Brainstem response audiometry (ABR) exhibited a very high sensitivity (100%), making it a suitable single test for screening patients suspected to have an acoustic neuroma.

Adolescent↗
PubMed1995

[Surgical treatment of space-occupying lesions in the nasal cavity and paranasal sinus involving the skull base].

This paper reports 29 cases of space-occupying lesions in the nasal cavities and the paranasal sinuses. Of them, 12 were benign and 17 malignant. They were all surgically treated, 17 by lateral rhinotomy, 6 by combined cranio-nasal approaches, 3 by maxillectomy and evisceration of the orbit, 1 by transfrontal and 1 by midfacial degloving approaches, respectively. The regional chemotherapy was administered to a case via external carotid artery after neck dissection. Among these cases, 18 of the skull defects were rehabilitated. The repairing materials included the autologous perpendicular plate of the ethmoid bone, the vomer, the septal cartilage, the middle turbinate and the internal laminae of the frontal bone or sinus. The meningeal defects in 14 cases were repaired using autologous muscle, fascia, galea aponeurotica. Except for one case of postoperative cerebrospinal rhinorrhea due to improper surgical approach, no cases had postoperative complications.

Adolescent↗
PubMed1995

[Transscleral suture fixation of posterior chamber intraocular lenses].

PURPOSE: To determine the effects of posterior chamber intraocular lens implantation in patients with ruptured capsules of after intracapsules cataract extraction. METHODS: Using transscleral suture fixation, posterior chamber intraocular lenses were implanted in 23 eyes (23 cases), including 13 eyes after intracapsular cataract extraction and 10 eyes with ruptured capsules due to complicated extracapsular cataract extraction or traumatic cataract. RESULTS: All the patients obtained satisfactory visual acuities of 20/40 or better. Few complications were observed in the follow-up period of 3 to 16 months. CONCLUSIONS: This technique makes it possible for almost all eyes after cataract extraction to be implanted posterior chamber intraocular lens.

Adult↗