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Biomedical subjects

Y H Chou

Publications and source records attributed to Y H Chou.

At least 91 records · Page 5Linked to original sources
PubMed1998

Torsion of a malignant undescended testis.

Cryptorchid testis have a greater risk of malignant change than do normally descended testis. The undescended testis would also be susceptible to torsion by the mechanism of increase in testicular size. A 36-year-old man of torsion of malignant undescended testis is presented. He was diagnosed as having incarcerated inguinal hernia on his first visit to general surgeon due to acute left lower abdominal pain. At laparotomy, a 7.5 x 5.5 x 3.0 cm3, greyish tan color mass was found. The pathological diagnosis is choricarcinoma and teratoma, mixed germ cell tumor. We would emphasise that in any patient presenting with acute abdominal symptoms and an absent scrotal testis, the possibility of a complication of torsion of undescended testis should be considered.

Adult↗
PubMed1998

Carbon-11-NNC 112: a radioligand for PET examination of striatal and neocortical D1-dopamine receptors.

UNLABELLED: The aim of this work was to explore the potential of a selective D1-dopamine receptor antagonist as a new radioligand for PET examination of striatal and neocortical D1-dopamine receptors. METHODS: The active (+)- and inactive (-)-enantiomers of [11C]NNC 112 were radiolabeled using the N-methylation approach and were examined by PET in cynomolgus monkeys and healthy men. Metabolite levels in plasma were measured by gradient high-performance liquid chromatography (HPLC). RESULTS: N-methylation of the corresponding desmethyl precursors with [11C]methyl triflate gave high total radiochemical yield (50%-60%) and specific radioactivity (110 GBq/micromol). (+)-[11C]NNC 112 binding in cynomolgus monkeys was 5.77+/-0.31 and 2.36+/-0.14 times higher in the striatum and neocortex, respectively, than in the cerebellum at a transient equilibrium that appeared 40-50 min after injection. The binding of (+)-[11C]NNC 112 is stereoselective, because the brain distribution of the inactive (-)-enantiomer was on an equally low level for all brain regions. Displacement and pretreatment experiments using unlabeled SCH 23390 and ketanserin confirms that (+)-[11C]NNC 112 binds specifically and reversibly to D1-dopamine receptors. The radioactivity ratios of the striatum, frontal cortex and nucleus accumbens to the cerebellum were 3.8-4.0, 1.7-2.0 and 2.8-3.1, respectively, at a transient equilibrium that appeared 40-50 min after injection in four healthy human subjects. Linear graphical analysis gave distribution volume ratios of 3.9 and 1.5 in the putamen and frontal cortex, respectively. The fraction of the total radioactivity in human plasma representing unchanged (+)-[11C]NNC 112 was 85% at 5 min and 25% at 75 min after injection. CONCLUSION: (+)-[11C]NNC 112 should be a useful PET radioligand for quantitative examination of not only striatal but neocortical D1-dopamine receptors in man.

Adult↗
PubMed1998

[Changing trends of ureteral injuries].

Ureteral injury is a potential complication of any abdominal or pelvic surgery. Gynecological surgery has traditionally accounted for most injuries. In the last decade, there have been major advances in endoscopic surgery including ureteroscopy and laparoscopy, both of which may cause ureteral injury. Increased use of these procedures change the nature of ureteral injuries. From 1988 to 1997, 22 patients with 24 ureteral injuries were identified. The causes, diagnostic methods and treatments were reviewed. Ureteral injury was defined as any laceration, transection or ligation of the ureter that required an unexpected procedure for repair, stent or drainage. In 24 ureteral injuries, there were 20 unilateral cases and 2 bilateral cases eight men (33%) were 15 to 43 years old (mean age 30), and 14 women including 2 case of bilateral lesion (67%) were 30 to 75 years old (mean age of 46). The injuries were on the right side in 11 cases (46%), left side 13 cases (54%), and in the upper, and lower third of the ureter in 7 (29%) and 17 cases (71%), respectively. Bilateral injuries were all in the lower ureter and another 2 cases of lower ureteral injuries were combined with bladder injuries. In the cases of ureteral injuries, iatrogenic injuries accounted for 19 cases (79%). Of these, urological surgery, laparoscopic surgery, ureteroscopic procedures and gynecological surgery accounted for 1 (4%), 2(8%), 5(21%) and 11 cases (46%) respectively. Between 1988 and 1992, there were 7 cases, and after 1993, there were 17 cases of ureteral injuries. The injuries caused by trauma and gynecological surgery remained stable in the 2 period. The recent increases were caused by endoscopic procedures including ureteroscopy and laparoscopy. Of the 24 cases, 13 cases (54%) were managed by ureteroneocystostomy, 5 cases (21%) by nephrectomy, 4 cases (17%) by ureteroureterotomy, 1 case by PCN and 1 case by double-J catheter stenting only. The early recognition and repair at injury allow for better results with fewer complications. Delayed finding or commitant infection may lead to failure of reconstructive procedure and lead to nephrectomy.

Adult↗
PubMed1997

Breast mass due to alveolar soft part sarcoma of the pectoris major muscle.

We present a case of alveolar soft part sarcoma (ASPS) of the pectoris major muscle in a 20-year-old female. She felt a mass in her right side breast for 7 years. The lesion was almost the same size with occasional throbbing pain and tenderness. Fine needle aspiration of the tumor was performed in the OPD and suspicious abnormal cells were reported. Ultrasound (US) examination of the breast revealed a large heterogeneously hypoechoic lesion contiguous to the pectoris major muscle. Profound color flow signals were evident in both central and peripheral regions of the mass. Spectral Doppler US showed high flow velocity in the tumor vessels with resistivity index of 0.73. Surgical intervention was performed and the histological examination yielded a diagnosis of ASPS.

Adolescent↗
PubMed1997

Intermediate filaments and cytoplasmic networking: new connections and more functions.

Recent research highlights the roles of cytoskeletal intermediate filaments (IFs) and their interactions with both the cell surface and other cytoskeletal systems in maintaining cellular integrity and the mechanical properties of cytoplasm. This has been demonstrated by analyses of mutations in IF-associated proteins (IFAPs) that are involved in connecting IFs to cell surface junctions. New data also point to the role of IFAPs as molecular 'nuts and bolts' in the construction of an integrated cytoplasmic architecture. This is highlighted by the initial descriptions of a family of multifunctional molecules that are capable of bridging IFs to other cytoskeletal elements. These findings, together with the development of specific peptide inhibitors capable of disassembling IF networks in vivo, are paving the way to the identification of new cellular functions for IFs and IFAPs.

Cytoplasm↗
PubMed1997

Retrobulbar haemodynamic changes studied by colour Doppler imaging in glaucoma.

PURPOSE: To determine the effect of spontaneously elevated intraocular pressure (IOP) on the ocular circulation, and evaluate the result of IOP-lowering procedures in terms of haemodynamics. METHODS: Colour Doppler imaging (CDI) was employed to determine the peak systolic velocity (PSV), end-diastolic velocity (EDV) and time average maximal velocity (TAMV), as well as the Pourcelot ratio (PR) and pulsatility index (PI), of the central retinal artery (CRA), posterior ciliary arteries (PCA) and ophthalmic artery. Various CDI parameters of the eyes with elevated IOP were compared with those of the clinically healthy fellow eyes and the control eyes, separately. Also, data from CDI of glaucoma eyes obtained during the period of elevated IOP and then following IOP-lowering procedures were compared, deliberately avoiding the influence of glaucoma medications. RESULTS: Eyes (n = 12) with elevated IOP showed significantly decreased flow velocities of the CRA and significantly increased PR and PI of the nasal and temporal PCA, compared with the fellow and control eyes, respectively. Following IOP-lowering procedures, the PR and PI of the nasal PCA decreased significantly. CONCLUSION: Spontaneously elevated IOP may induce haemodynamic changes in the CRA and PCA, but no significant change is identified in the ophthalmic artery. Flow velocities tend to decrease while the resistance indices tend to increase with elevated IOP. Such haemodynamic changes may reverse following normalisation of IOP.

Aged↗
PubMed1997

Percutaneous drainage in the treatment of emphysematous pyelonephritis: 10-year experience.

PURPOSE: We investigated the effect of percutaneous drainage for the treatment of emphysematous pyelonephritis. MATERIALS AND METHODS: A retrospective analysis was done of 25 patients with emphysematous pyelonephritis who were treated initially with computerized tomography (CT) guided percutaneous drainage during a 10-year period. The patients were concomitantly treated with antibiotics, fluids, and correcting blood glucose and/or ureteral obstruction. We also compared our results of percutaneous drainage to CT findings. RESULTS: CT identified 12 patients with emphysematous pyelonephritis who had gas with little fluid and 13 who had gas with renal or perirenal fluid collections. In 20 of 25 patients (80%) antibiotic therapy combined with percutaneous drainage constituted the only treatment required. Three patients (12%) whose clinical status improved after percutaneous drainage subsequently underwent elective nephrectomy without further complications. Two patients (8%) died of multiple organ failure. There was no correlation between the gas patterns of emphysematous pyelonephritis and initial success with the antibiotics and percutaneous drainage. There were no recurrences and no complications during a followup of 1 to 10 years (mean 5). Mean duration of treatment was 5.54 weeks (range 1 to 12.6). CONCLUSIONS: CT is an efficient imaging method for diagnosis, guiding the drainage procedures and monitoring response to percutaneous drainage of emphysematous pyelonephritis. Antibiotic therapy combined with CT guided percutaneous drainage of emphysematous pyelonephritis is an acceptable alternative to antibiotic therapy with surgical intervention.

Adult↗
PubMed1997

The correlation between ultrasound-detected renal parenchymal thickness and isotope-detected individual renal function.

Ultrasound has been used as a convenient examination method to obtain an estimate of the kidney size and parenchymal thickness. The aim of this study was to determine the relationship between the renal parenchymal thickness and individual renal function. Renal ultrasonography to determine parenchymal thickness and 99mTc-DTPA renal scan to detect individual renal function were carried out on 30 patients. The statistic analysis showed poor correlation between these two factors. The correlation coefficients is 0.1 only. However, the correlation coefficients of the difference of bilateral renal parenchymal thickness and the difference of bilateral renal function in the same patient is much higher (r = 0.67). So, it is unreliable to predict the random single renal function based on parenchymal thickness only. However, in the same patient, it is sometimes worthwhile to differentiate bilateral renal function based on the difference of renal parenchymal thickness between the two kidneys.

Adult↗
PubMed1996

The function of intermediate filaments in cell shape and cytoskeletal integrity.

This study describes the development and use of a specific method for disassembling intermediate filament (IF) networks in living cells. It takes advantage of the disruptive effects of mimetic peptides derived from the amino acid sequence of the helix initiation 1A domain of IF protein chains. The results demonstrate that at 1:1 molar ratios, these peptides disassemble vimentin IF into small oligomeric complexes and monomers within 30 min at room temperature in vitro. Upon microinjection into cultured fibroblasts, these same peptides induce the rapid disassembly of IF networks. The disassembly process is accompanied by a dramatic alteration in cell shape and the destabilization of microtubule and actin-stress fiber networks. These changes in cell shape and IF assembly states are reversible. The results are discussed with respect to the roles of IF in cell shape and the maintenance of the integrity and mechanical properties of the cytoplasm, as well as the stability of the other major cytoskeletal systems.

3T3 Cells↗
PubMed1996

Accumulation of Ga-67 citrate in a tuberculous splenic abscess. Report of a rare case.

A case of 65-year-old man with tuberculous splenic abscess is presented. The Ga-67 citrate scan revealed three focal areas of increased uptake in the left upper quadrant of the abdomen. The combined Tc-99m SC/Ga-67 scans revealed that these Ga-67 avid lesions localized in the splenic photon-deficit areas found in the Tc-99m SC scan. This case demonstrated the usefulness of Ga-67 imaging in a survey of fever of unknown origin in unsuspected tuberculous splenic abscess.

Abscess↗
PubMed1996

The relative roles of specific N- and C-terminal phosphorylation sites in the disassembly of intermediate filament in mitotic BHK-21 cells.

Previously we identified p34cdc2 as one of two protein kinases mediating the hyperphosphorylation and disassembly of vimentin in mitotic BHK-21 cells. In this paper, we identify the second kinase as a 37 kDa protein. This p37 protein kinase phosphorylates vimentin on two adjacent residues (thr-457 and ser-458) which are located in the C-terminal non-alpha-helical domain. Contrary to the p34cdc2 mediated N-terminal phosphorylation (at ser-55) which can disassemble vimentin intermediate filaments (IF) in vitro, p37 protein kinase phosphorylates vimentin-IF without obviously affecting its structure in vitro. We have further examined the in vivo role(s) of vimentin phosphorylation in the disassembly of the IF network in mitotic BHK cells by transient transfection assays. In untransfected BHK cells, the interphase vimentin IF networks are disassembled into non-filamentous aggregates when cells enter mitosis. Transfection of cells with vimentin cDNA lacking the p34cdc2 phosphorylation site (ser55:ala) effectively prevents mitotic cells from disassembling their IF. In contrast, apparently normal disassembly takes place in cells transfected with cDNA containing mutated p37 kinase phosphorylation sites (thr457:ala/ser458:ala). Transfection of cells with vimentin cDNAs lacking both the N- and C-terminal phosphorylation sites yields a phenotype indistinguishable from that obtained with the single N-terminal mutant. Taken together, our results demonstrate that the site-specific phosphorylation of the N-terminal domain, but not the C-terminal domain of vimentin plays an important role in determining the state of IF polymerization and supramolecular organization in mitotic cells.

Animals↗
PubMed1996

[Experiment study on biological and immunological characteristics of modified DNL of oral squamous cell carcinoma with TNF-alpha gene]

Growing characteristic of gene-transduced and nontransduced DNL in medium of containing rIL-2 was compared,and growing characteristic of gene-transduced DNL in medium of non containing rIL-2 was analyzed.DNA index (DI),cell cycle and immunologic phenotypes of gene-transduced and nontransduced DNL were analyzed with FACS.The results revealed interfered with growth,DL,cell cycle and immunologic phenotypes of DNL,and gene-transduced DNL couldn't growing infinitely.

Journal Article↗
PubMed1996

Sonographic signs of complete rotator cuff tears.

BACKGROUND: To evaluate the usefulness of high resolution ultrasound (HRUS) in the examination of complete rotator cuff tear (RCT). METHODS: A prospective study of 157 patients with sonographic examination of shoulder was performed. All of them complained of chronic shoulder pain and were referred by clinician for suspicion of RCT. Their age ranged from 30 to 76 years. The ultrasonic scanners we used were Acuson 128 XP 10 with 7MHz linear transducer, or Diasonics VST master series using 10MHz linear transducer. Examination positions included external rotation of shoulder for scanning biceps tendon and subscapularis tendon, and internal rotation for supraspinatus tendon and lateral scan of infraspinatus tendon and teres minor tendon. Sonographic criteria of complete RCT included 1. complete absence of rotator cuff (RC); 2. focal thinning of RC; 3. focal hypoechoic cleft of RC; 4. focal depression of RC; and 5. heterogeneous hypoechoic RC with subdeltoid bursa fluid. Arthrography was performed after sonography examination on the same day. RESULTS: Among 49 complete RCTs diagnosed by sonography, 46 were proved to be complete RCT by arthrography; only 3 were false positive. In 108 patients with normal rotator cuff diagnosed by sonography, 104 had compatible results with arthrography; only 4 patients turned out to be complete RCT. The sensitivity, specificity, positive predictive values, negative predictive values and accuracy were 92%, 97.2%, 93.9%, 96.3% and 95.5%, respectively. CONCLUSIONS: HRUS can directly demonstrate the morphological changes of RC. It has a high sensitivity and specificity in the diagnosis of complete RCT, and can be used as a firstline screening modality for complete RCT in patients with chronic shoulder pain.

Adolescent↗
PubMed1995

Cell cycle phase-dependent changes of localization and oligomerization states of nucleophosmin / B23.

Nucleophosmin / B23, an abundant nucleolar phosphoprotein, accumulates in the nucleoplasm of cells during the stationary phase of growth or after exposure to selected cytotoxic drugs [Chan, P.K. (1992) Exp. Cell Res. 203, 174-181]. Monomeric and hexameric forms of nucleophosmin / B23 are present in cells [Yung, B.Y.M. and Chan, P.K. (1987) Biochim. Biophys. Acta. 925, 74-82]. Using indirect immunofluorescence, here we show that there are changes in nucleophosmin / B23's cellular localizations throughout the cell cycle. The alternation of the nuclear and nucleolar localizations of nucleophosmin / B23 is most frequently observed in cells of G1 and G1/S phases. The incidence of the changes of localizations of nucleophosmin / B23 decreases as cells enter into S and G2 phases. In parallel, using Western blotting, the reversible change of oligomerization states between the hexameric and monomeric forms of nucleophosmin / B23 is also found to occur most frequently in cells of G1 and G1/S phases. As cells progressed into S, G2 and M phases, the frequency of the reversible change of hexameric and monomeric forms of nucleophosmin / B23 decreases. These findings suggest that nucleophosmin / B23 being possibly involved in rRNA processing and transport, is highly active at G1 and G1/S phases as demonstrated by the dynamic, reversible changes of localization and oligomerization states of nucleophosmin / B23.

Biological Transport, Active↗
PubMed1995

Cloning and functional characterization of extracellular Ca(2+)-sensing receptors from parathyroid and kidney.

Parathyroid cells recognize and respond to (i.e., "sense") minute perturbations in the extracellular ionized calcium concentration (Ca2+o), but the mechanisms underlying this process have remained obscure. Recently, we employed expression cloning in Xenopus laevis oocytes to isolate a cDNA coding for a Ca2+o-sensing receptor from bovine parathyroid. Like the native receptor, the cloned Ca2+o-sensing receptor stimulates phospholipase C (PLC) in a G-protein-dependent manner with a nearly identical pharmacological profile. Its deduced amino acid sequence confirms that it is a member of the superfamily of G-protein-coupled receptors (GPR). Transcripts for the receptor are expressed in parathyroid and other tissues that sense Ca2+o (viz., kidney and thyroidal C-cells) as well as those that have no known role in extracellular Ca2+ homeostasis, such as the brain. The availability of the cDNA clone for the Ca2+o-sensing receptor made it possible to test the hypothesis that mutations in the gene encoding the human homolog of the receptor cause inherited disorders of mineral ion metabolism. Familial hypocalciuric hypercalcemia (FHH) and neonatal severe hyperparathyroidism (NSHPT) are, in fact, caused by mutations that reduce the activity of the receptor when they are present in the heterozygous and homozygous states, respectively. In contrast, we have subsequently discovered a family in which a form of autosomal dominant hypocalcemia results from an activating mutation in the receptor gene. The Ca2+-sensing receptor, therefore, permits Ca2+o to play a "hormonelike" role as an extracellular first messenger in addition to its well described role as an important intracellular second messenger.

Amino Acid Sequence↗
PubMed1995

The cloning of extracellular Ca(2+)-sensing receptors from parathyroid and kidney: molecular mechanisms of extracellular Ca(2+)-sensing.

The parathyroid cell detects changes in the extracellular ionized calcium concentration (Ca2 + o) with exquisite sensitivity, but the mechanisms through which it senses Ca2 + o have remained obscure. Recently, we isolated a cDNA encoding a Ca2 + o-sensing receptor from bovine parathyroid using expression cloning in Xenopus laevis oocytes. The expressed receptor stimulates phospholipase C and has a pharmacological profile almost identical to that of the native receptor. Furthermore, its deduced amino acid sequence confirms that it belongs to the superfamily of G-protein-coupled receptors. Receptor transcripts are present in parathyroid and other tissues sensing Ca2 + o (e.g., kidney and thyroidal C-cells) as well as those not known to be involved in Ca2+ homeostasis (viz., in the brain). We have also shown that mutations in the receptor cause three inherited disorders of calcium metabolism: Familial hypocalciuric hypercalcemia (FHH) and neonatal severe hyperparathyroidism (NSHPT) result from inactivating mutations, when present in the heterozygous and homozygous states, respectively, whereas an autosomal dominant form of hypocalcemia is due to an activating mutation. Thus this Ca2 + o-sensing receptor permits Ca2+o to act as an extracellular, first messenger in addition to its better known role as an intracellular second messenger.

Animals↗
PubMed1995

An unusual testicular metastasis from transitional cell carcinoma of the ureter: a case report.

Testicular tumor metastasis from transitional cell carcinoma (TCC) of the ureter is very rare. Herein, we report a case who presented with a palpable mass of left testis, after he underwent radical nephroureterectomy and bladder cuff excision and adjuvant radiotherapy and chemotherapy for the TCC of left ureter tumor for 5 months. We performed left radical orchiectomy and histology revealed a TCC identical to the original ureteral tumor. In a review of the literature, we found this case was the second case of metastatic testicular tumor from the ureteral TCC. In patients presenting the symptom of a palpable testicular mass, if they are known to have a ureteral TCC, metastatic neoplasm should be considered in the differential diagnosis, even if in the absence of other systemic metastasis.

Carcinoma, Transitional Cell↗