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Biomedical subjects

Y H Chou

Publications and source records attributed to Y H Chou.

At least 19 recordsLinked to original sources
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

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↗
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

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↗
PubMed1995

Umbilical venous line related pericardial effusion in a premature neonate: report of a case.

Cardiac tamponade occurs very rarely, but is life-threatening in the newborn. This paper reports a premature newborn who developed profound shock 25 hours after undergoing umbilical venous catheterization. Echocardiography taken later, showed marked pericardial effusion. An umbilical venous catheter was located in the left atrium. Immediate pericardiocentesis was performed, 11 mL of a clear straw-colored fluid was removed and the umbilical venous catheter was withdrawn into the inferior vena cava. The heart rate and blood pressure recovered immediately. Analysis of the pericardial fluid showed a high glucose level of 2,451 mg/dL. There was no pericardial effusion reaccumulation thereafter. Rapid diagnosis and treatment of pericardial effusion are mandatory to prevent subsequent morbidity and mortality when disastrous episodes, such as in the present case, occur.

Cardiac Tamponade↗
PubMed1995

[Epidermoid cyst of testis: benign testicular tumor].

Epidermoid cyst of the testis is very rare and accounts for approximately 1% of all testicular tumors. In the clinical examination, the testis has a palpable mass. Pathological findings usually reveal a squamous cell lined cyst, containing keratin, and the absence of appendages and teratoma element. If scrotum ultrasonography reveals a target sign suggestive of epidermoid cyst, the testis should be explored through an inguinal incision. Clamp the spermatic cord gently, and perform tumor enucleation. The frozen section is available at the time to check for any malignant cells. If no malignant cells exist, it is important to perform testis-preserving surgery, especially for young adults and children. We report two cases of epidermoid cyst. Serum beta-HCG and alpha-fetoprotein were within normal limits. We review our experience with scrotum ultrasonography and testis-preserving surgery in 2 men with epidermoid cyst to indicate when the clinical and intraoperative characteristics justify testis-preserving management.

Adolescent↗
PubMed1995

Mutations in the human Ca(2+)-sensing-receptor gene that cause familial hypocalciuric hypercalcemia.

We report five novel mutations in the human Ca(2+)-sensing-receptor gene that cause familial hypocalciuric hypercalcemia (FHH) or neonatal severe hyperparathyroidism. Each gene defect is a missense mutation (228Arg-->Gln, 139Thr-->Met, 144Gly-->Glu, 63Arg-->Met, and 67Arg-->Cys) that encodes a nonconservative amino acid alteration. These mutations are each predicted to be in the Ca(2+)-sensing receptor's large extracellular domain. In three families with FHH linked to the Ca(2+)-sensing-receptor gene on chromosome 3 and in unrelated individuals probands with FHH, mutations were not detected in protein-coding sequences. On the basis of these data and previous analyses, we suggest that there are a wide range of mutations that cause FHH. Mutations that perturb the structure and function of the extracellular or transmembrane domains of the receptor and those that affect noncoding sequences of the Ca(2+)-sensing-receptor gene can cause FHH.

Calcium↗
PubMed1995

Recent experience of penile fracture (1989-1993).

Penile fracture is an uncommon injury in the genitourinary organ which occurs following a blunt injury on the rigid penis. Penile fracture with urethral injury is even rarer. A total of 11 new patients with penile fracture were treated at our institution from 1989 to 1993. All of these injuries occurred during sexual intercourse and received immediate surgical repair to preserve the sexual function. Only one patient with complete transection of the urethra received end-to-end anastomosis of the urethra. Unfortunately, he suffered from urethral-cutaneous fistula ten days later. Suprapubic urinary diversion was performed in 3 patients with partial urethral tearing, and they enjoyed satisfactory outcomes during the limited follow-up. Immediate surgical repair of tunica albuginea is recommended for preserving penile function. If associated with partial urethral tear, suprapubic urinary diversion is sufficient to treat urethral lesions.

Adult↗
PubMed1995

Comparison of radioisotopic and ultrasonic scanning in the evaluation of neonatal hypothyroidism.

BACKGROUND: Technetium-99m pertechnetate (Tc-99m) scan is presently the best diagnostic modality to delineate the anatomy of the neonatal thyroid. Because several factors will inhibit Tc-99m uptake in a normal thyroid gland and the Tc-99m scan requires expensive equipment and sometimes raises fear of radiation in parents, the ultrasonography might be an important complementary method for neonatal thyroid disorders. We described our experience with ultrasonography of the thyroid in 52 infants with suspected congenital hypothyroidism to compare the results obtained by using Tc-99m imaging in the same infants. METHODS: From Dec. 1991 to May 1992, 52 neonates with suspected congenital hypothyroidism by newborn screening were referred to Veterans General Hospital-Taipei for confirmatory diagnoses. All of them were investigated with Tc-99m and ultrasonography of the thyroid gland. Results of Tc-99m scan and ultrasonography were compared and analyzed. RESULTS: The ultrasonography failed to identify any ectopic gland and all cases were misinterpreted as hypoplasia or hemiagenesis of thyroid gland, but it never misinterpreted them as normal thyroid glands. The ultrasound never misinterpreted normal thyroid gland, while the Tc-99m scan misguided a normal gland as an athyreotic gland. CONCLUSIONS: The ultrasonography may be adopted as the first line image examination for the babies with suspected congenital hypothyroidism. If sonography shows abnormal thyroid gland such as hypoplasia, hemiagenesis or agenesis, the isotopic scan may be a good complementary method to confirm the diagnosis.

Female↗
PubMed1994

Intestinal schistosomiasis japonica: CT-pathologic correlation.

PURPOSE: To study the pathologic basis of intestinal wall calcification caused by Schistosoma japonicum visualized with computed tomography (CT). MATERIALS AND METHODS: Twelve patients underwent CT of the abdomen to detect what pathologic examination proved to be schistosomiasis japonica. Eight intestinal specimens from five of the patients were subjected to radiography, and the pathologic and radiographic findings were correlated. RESULTS: CT demonstrated curvilinear or nodular calcification in the colon in 11 patients, in the appendix in two, and in the distal ileum in one. In five patients, calcifications resembling tram tracks were found in the sigmoid colon. Pathologic examination of the specimens showed calcified eggs of S japonicum deposited more extensively in the submucosa and subserosa than in the muscularis propria, which led to the tram-track appearance. CONCLUSION: The extensive curvilinear or tram-track calcification found in the colon in patients with schistosomiasis japonica is calcification of deposited eggs.

Aged↗