Biomedical subjects

S C Chen

Publications and source records attributed to S C Chen.

At least 91 records · Page 5Linked to original sources

PubMed2001

Distribution and dynamics of gap junction channels revealed in living cells.

To study the structural composition and dynamics of gap junctions in living cells, we tagged their subunit proteins, termed connexins, with the autofluorescent tracer green fluorescent protein (GFP) and its cyan (CFP) and yellow (YFP) color variants. Tagged connexins assembled normally and channels were functional. High-resolution fluorescence images of gap junction plaques assembled from CFP and YFP tagged connexins revealed that the mode of channel distribution is strictly dependent on the connexin isoforms. Co-distribution as well as segregation into well-separated domains was observed. Based on accompanying studies we propose that channel distribution is regulated by intrinsic, connexin isoform specific signals. High-resolution time-lapse images revealed that gap junctions, contrary to previous expectations, are dynamic assemblies of channels. Channels within clusters and clusters themselves are mobile and constantly undergo structural rearrangements. Movements are complex and allow channels to move, comparable to other plasma membrane proteins not anchored to cytoskeletal elements. Comprehensive analysis, however, demonstrated that gap junction channel movements are not driven by diffusion described to propel plasma membrane protein movement. Instead, recent studies suggest that movements of gap junction channels are indirect and predominantly propelled by plasma membrane lipid flow that results from metabolic endo- and exocytosis.

Cell Membrane↗

PubMed2001

Effectiveness of transperitoneal and trans-retroperitoneal laparoscopic adrenalectomy versus open adrenalectomy.

PURPOSE: This study compared the effectiveness of laparoscopic adrenalectomy, using either a transperitoneal or trans-retroperitoneal approach, with that of open adrenalectomy in patients with benign adrenal tumors. METHODS: From February 1995 to April 2000, laparoscopic adrenalectomy was performed on 31 patients with adrenal tumors, including 16 aldosteronomas, 10 Cushing's adenomas, three nonfunctioning tumors, and two pheochromocytomas. A lateral trans-retroperitoneal approach was used for the first 16 patients and a lateral transperitoneal approach was used for the last 15 patients. Twenty-one patients who received open adrenalectomy during the same period served as a control group. Comparisons were made between laparoscopy and open groups, and between transperitoneal and trans-retroperitoneal groups. RESULTS: Conversion to open adrenalectomy was necessary in two cases--both in the trans-retroperitoneal group during the first 2 years of the study period. No other intraoperative complications occurred and blood transfusion was not used. Compared with the open group, the laparoscopic group had less blood loss (71 vs 124 mL), resumed oral feeding earlier (28 vs 60 hr), required less postoperative narcotics (45 vs 120 mg meperidine), and had shorter postoperative hospital stays (4.9 vs 7.6 days) (all p < 0.05). The mean operative time was longer in the laparoscopic group (203 vs 123 min, p < 0.001). There were no significant differences between the transperitoneal and trans-retroperitoneal laparoscopy groups in any of the studied parameters, except that the operative time was longer in the trans-retroperitoneal laparoscopy group (244 vs 166 minutes, p < 0.01). CONCLUSIONS: Decreased blood loss, less postoperative pain, earlier resumption of oral feeding, and shorter hospital stays were achieved in patients undergoing laparoscopic adrenalectomy. These findings indicate that laparoscopic adrenalectomy is the treatment of choice for benign adrenal tumors. The transperitoneal approach yielded shorter operative time than the trans-retroperitoneal approach, because it offered a clearer view and familiar landmarks.

Adrenalectomy↗

PubMed2001

Depentylation of the rat esophageal carcinogen, methyl-n-pentylnitrosamine, by microsomes from various human and rat tissues and by cytochrome P450 2A3.

Methyl-n-pentylnitrosamine (MPN) is carcinogenic for the rat esophagus. To determine organ specificity for MPN activation by human tissues, microsomes isolated from human organs (snap-frozen <6 h after death or removed surgically) were incubated with [pentyl-(3)H]MPN, and [(3)H]pentaldehyde formation was measured by high-pressure liquid chromatography of its 2,4-dinitrophenylhydrazone using radioflow assay. With 100 microM MPN, mean depentylation rates were 6.6 (liver), 2.9 to 3.8 (kidney, stomach, small intestine, and colon), and 0.4 to 1.6 (esophagus, lung, and skin) pmol of pentaldehyde/mg of protein/min. Of 14 human esophagi, four showed relatively high depentylation rates of 3.3 to 4.1 pmol/mg/min. Apparent K(m) was 80 to 160 microM (V(max), 3-15 pmol/mg/min) for three esophagi, 90 to 130 (2 livers), and 1330 (1 kidney) microM. Rat tissues showed mean depentylation rates for 100 microM MPN of 24.9 (liver), 14.5 (esophagus), 7.0 (lung), and 0.0 to 2.7 (5 other tissues) pmol/mg/min. MPN depentylation by rat cytochrome P450 2A3 showed an apparent K(m) of 8 microM (V(max), 70 pmol/nmol of P450/min) and was competitively inhibited by the CYP2A inhibitor coumarin (apparent K(i), 4 microM). Coumarin (0.4 mM) inhibited microsomal depentylation of 100 microM MPN by 37 to 62% for human esophagus, liver, kidney, and colon and for rat esophagus but not for rat liver and lung. MPN depentylation by rat esophageal microsomes increased up to 90% on adding P450 reductase. The results indicate organ-specific MPN metabolism by rat but not human esophagus. Nevertheless, the relatively high activity of four human esophagi might indicate increased susceptibility of some individuals to carcinogenesis by unsymmetrical dialkylnitrosamines.

Adult↗

PubMed2001

Changing prevalence of hepatitis C virus genotypes: molecular epidemiology and clinical implications in the hepatitis C virus hyperendemic areas and a tertiary referral center in Taiwan.

To determine the hepatitis C virus (HCV) genotype distribution in Taiwan and to clarify the relationship between genotype and the pathogenesis of HCV infection, 1,164 subjects positive for serum HCV antibodies and HCV RNA from three HCV hyperendemic areas (Masago, Tzukuan, and Taoyuan) and a tertiary referral center in Taiwan were studied during 1995-1997. HCV genotypes and viral loads were determined using Okamoto's method and branched DNA assay, respectively. Genotype 1b was the most prevalent in Tzukuan (61.9%), Taoyuan (76.9%), and the referral center (47.0%). By contrast, genotype 2a was the major HCV type in Masago (63.5%). Prevalence of genotype 1b positively and that of genotype 2a negatively correlated to age, regardless of study populations (P < 0.01). Based on multivariate analysis, the significant factors associated with the presence of cirrhosis, with or without hepatocellular carcinoma, in chronic hepatitis C patients were genotype 1b and age. In conclusion, these results underline that independent HCV outbreaks continue in HCV hyperendemic areas in Taiwan, concomitant with a changing relative prevalence of HCV genotypes in relation to age. Both the correlation of genotype 1b with age (cohort effect) and intrinsic properties of HCV genotypes are probably responsible for the association between genotype and the pathogenesis of HCV infection.

Adolescent↗

PubMed2001

Reoperative Snodgrass procedure.

PURPOSE: We examine the results of a reoperative Snodgrass procedure for complex hypospadias. MATERIALS AND METHODS: A total of 25 patients with hypospadias in whom repair had failed underwent a reoperative Snodgrass procedure. Mean patient age and number of prior repairs were 11.4 years and 2.5, respectively. Before this treatment the meatus was at the distal shaft in 10 cases, mid shaft in 9, proximal shaft in 4 and penoscrotal junction in 2. Preoperatively the associated complications were fistulas in 13 patients, residual chordee in 12 and diverticulum in 1. In 8 cases the fistula was incorporated into the hypospadiac opening and treated as a longer defect. The urethral plates were, subjectively, surgically altered or unaltered in 7 and 18 patients, respectively. In 8 patients (group A) the previous repair(s) did not involve dissection of the urethral plate (unaltered) nor was there a fistula. The remaining 17 patients were classified as group B. The neourethra was then reconstructed as the Snodgrass technique. Followup urethral calibration was performed in 17 patients. RESULTS: Mean followup period was 13.7 months. Mean length and size of neourethra were 19.9 mm. and 14Fr, respectively. There were 7 (28%) postoperative fistulas of the neourethra. The incidences of postoperative fistula of the neourethra were 0% and 41.2% in groups A and B, respectively (p <0.01). Statistically the surgically altered urethral plate and the presence of a preoperative fistula were 2 independent factors predicting a higher postoperative fistula rate. The overall postoperative meatal stenosis rate was 13 (52%) with 3 (37.5%) in group A and 10 (58.8%) in group B, respectively (p >0.05). The meatal stenosis was treated with simple dilation in 11 cases and meatoplasty during subsequent fistula repair in 2. Stricture at the anastomostic site between the normal urethra and neourethra was noted in 2 patients. Fistula repair was successfully performed 6 months later in 4 patients. CONCLUSIONS: The Snodgrass procedure is a viable option for the treatment of previously failed hypospadias repair. It was highly effective in patients with a surgically unaltered urethral plate and no preoperative fistula.

Adolescent↗

PubMed2001

Ultrasonic characteristics of periportal collateral circulation in hepatocellular carcinoma with portal vein invasion.

Real-time ultrasound (US) was used to analyze the morphological characteristics of periportal collateral circulation (PPCC) and the hepatic artery in hepatocellular carcinoma (HCC) patients with portal vein invasion (PVI). During a 5-year interval, a total of 17 HCC patients with main portal vein thrombosis and detectable periportal vessels were collected: 14 men and 3 women, aged 27 to 76 years old. We examined these patients' periportal vessels by real-time US, then differentiated PPCC from hepatic artery by duplex Doppler US. We analyzed the morphological appearances of real-time US imaging of PPCC and the hepatic artery. Our results showed that the PPCC was always torturously worm-like in appearance on real-time US, and the hepatic artery usually had a linear channel appearance on real-time US. When these two kinds of vessels were seen simultaneously along the pathway of a thrombosed portal vein, the inner vessel was always the hepatic artery with linear channel structure, and the outer vessel was always PPCC with a torturously worm-like structure. In conclusion, real-time US is a useful and reliable modality in detecting periportal vessels and differentiating PPCC from the hepatic artery.

Adult↗

PubMed2001

The effects on vesicourethral function following laparoscopic hysterectomy.

The aim of our study is to determine whether laparoscopic hysterectomy is associated with increased postoperative urinary symptoms and to assess the change in urodynamic parameters after operation. Forty-five women were arranged for laparoscopic hysterectomy (LH). Each patient received urinalysis, interview, and urodynamic study including uroflowmetry, filling and voiding cystometry and urethral pressure profilometry before and after hysterectomy. A total of 27 patients (60%) had urinary symptoms preoperatively. After operation, only 22 patients (48.9%) remained symptomatic. There was no significant change in the number of women with one or more voiding symptoms before and after surgery, but the incidence of urinary frequency and stress incontinence decreased significantly after laparoscopic hysterectomy (P < 0.05). In addition, maximal urethral closure pressure and maximal cystometric capacity showed significant increases after operation. They were 73.1 cm H2O (range: 49-114) vs 104.4 cm H2O (range: 60-147) (P < 0.001), and 363.3 ml (range: 287-423) vs 396.1 ml (range: 265-515) (P < 0.001), respectively. The result indicated that laparoscopic hysterectomy did not significantly increase the subjective or objective incidence of vesicourethral dysfunction. On the contrary, some patients might be cured of urinary frequency or stress incontinence postoperatively.

Adult↗

PubMed2001

Pseudo-Meigs syndrome and elevated levels of tumor markers associated with benign ovarian tumors--two case reports.

Elevated tumor markers for a post-menopausal woman presenting with a multilocular adnexal mass, ascites, and pleural effusion were interpreted as being highly suspicious of malignancy. This paper describes two cases of ovarian tumors presenting with all signs of malignancy. Following surgical excision of the masses, and histopathological assay, a benign pure struma ovarii and a mucinous cystadenoma were diagnosed by pathologists. The immediate and complete resolution of symptoms were achieved post-operatively, and the previously-evident abnormal tumor markers rapidly declined to the normal range, the two tumors were subsequently classified as pseudo-Meigs' syndromes.

Aged↗

PubMed2001

External beam radiation therapy for inoperable hepatocellular carcinoma with portal vein thrombosis.

Portal vein thrombosis (PVT) in patients with hepatocellular carcinoma (HCC) has a poor impact on prognosis. Many of these tumors may cause intrahepatic and extrahepatic metastases. From January 1991 to December 1996, 41 unresectable HCC patients with PVT underwent transcatheter arterial chemoembolization (TACE) and external beam radiation therapy (EBRT) to the portion of PVT. The irradiated field, with a mean equivalent field size of 6.6 x 7.1 cm2, was localized and simulated by abdominal sonography, angiography and computed tomography. Radiation dose ranged from 36 to 66 Gy (mean dose: 51.4 Gy), in a daily fraction of 1.8 to 2 Gy. The response of EBRT was evaluated by abdominal sonography within 3 months of completion of EBRT. The response rates of the PVT after treatment were 39% for complete response (CR), 41% for partial response (PR), and 19% for no response (NR), respectively. The median overall survival time from start of radiotherapy was 10 months for all patients, 17 months for CR patients, 8 months for PR patients and 4 months for NR patients. By multivariate analysis, response of PVT resulted in a significant improvement in survival. (P = 0.001) There was no occurrence of severe complication of radiation-induced liver disease. The results obtained with combined treatment modality of EBRT and TACE in the treatment of HCC patients with PVT are encouraging.

Adult↗

PubMed2000

Biochemical properties and cDNa cloning of two new lectins from the plasma of Tachypleus tridentatus: Tachypleus plasma lectin 1 and 2+.

A Sepharose CL-4B-binding protein, Tachypleus plasma lectin 1 (TPL-1), and a lipopolysaccharide (LPS)-binding protein, Tachypleus plasma lectin-2 (TPL-2), have been isolated from the plasma of Tachypleus tridentatus and biochemically characterized. Each protein is coded by a homologous family of multigenes. TPL-1 binds to Sepharose CL-4B and was eluted with buffer containing 0.4 m GlcNAc. The deduced amino acid sequence of TPL-1 consisted of 232 amino acids with an N-glycosylation site, Asn-Gly-Ser at residues 74-76. It shares a 65% sequence identity and similar internal repeats of about 20 amino acid motifs with tachylectin-1. Tachylectin-1 was identified as a lipopolysaccharide-agarose binding nonglycosylated protein from the amebocytes of T. tridentatus. TPL-2 was eluted from the LPS-Sepharose CL-4B affinity column in buffer containing 0.4 m GlcNAc and 2 m KCl. The deduced amino acid sequence of TPL-2 consisted of 128 amino acids with an N-glycosylation site, Asn-Cys-Thr, at positions 3-5. It shares an 80% sequence identity with tachylectin-3, isolated from the amebocytes of T. tridentatus. TPL-2 purified by LPS-affinity column from the plasma predominantly exists as a dimer of a glycoprotein with an apparent molecular mass of 36 kDa. Tachylectin-3 is an intracellular nonglycosylated protein that also exists as a dimer in solution with an apparent molecular mass of 29 kDa. It recognizes Gram-negative bacteria through the 0-antigen of LPS. Western blot analyses showed that, in the plasma, TPL-1 and TPL-2 exist predominantly as oligomers with molecular masses above 60 kDa. They both bind to Gram-positive and Gram-negative bacteria, and this binding is inhibited by GlcNAc. Possible binding site of TPL-1 and TPL-2 to the bacteria could be at the NAc moiety of GlcNAc-MurNAc of the peptidoglycan. The physiological function of TPL-1 and TPL-2 is most likely related to their ability to form a cluster of interlocking molecules to immobilize and entrap invading organisms.

Amino Acid Sequence↗

PubMed2000

Purification and characterization of secretory phospholipase B, lysophospholipase and lysophospholipase/transacylase from a virulent strain of the pathogenic fungus Cryptococcus neoformans.

Infection caused by the fungus Cryptococcus neoformans is potentially fatal. A highly active extracellular phospholipase, demonstrating phospholipase B (PLB), lysophospholipase (LPL) and lysophospholipase/transacylase (LPTA) activities, was purified to homogeneity from C. neoformans using (NH(4))(2)SO(4) fractionation, and hydrophobic-interaction, anion-exchange and gel-filtration chromatography. All three enzyme activities co-purified as a single protein with an apparent molecular mass of 70-90 kDa by SDS/PAGE and 160-180 kDa by gel filtration. The ratio of the three activities remained constant after each purification step. The amino acid composition, as well as the sequences of the N-terminus and of five internal peptide fragments were novel. The protein was an acidic glycoprotein containing N-linked carbohydrate moieties, with pI values of 5.5 and 3.5. The apparent V(max) values for PLB and LPL activities were 12.3 and 870 micromol/min per mg of protein respectively; the corresponding K(m) values were approx. 185.3 and 92.2 microM. The enzyme was active only at acidic pH (pH optimum of 4.0 for PLB and 4.0-5.0 for LPL and LPTA). Enzyme activity did not require added cations, but was inhibited by Fe(3+). LPL and LPTA activities were decreased by 0.1% (v/v) Triton X-100 to 50% of the control value. Palmitoylcarnitine (0.5 mM) inhibited PLB (97% inhibition) and LPL and LPTA activities (35% inhibition) competitively. All phospholipids except phosphatidic acid were degraded by PLB, but dipalmitoyl phosphatidylcholine and dioleoyl phosphatidylcholine were the preferred substrates. This is the first complete description of the purification and properties of a phospholipase, which may be involved in virulence, from a pathogenic fungus.

Acyltransferases↗

PubMed2000

Transgenic expression of the chemokine receptor encoded by human herpesvirus 8 induces an angioproliferative disease resembling Kaposi's sarcoma.

Human herpesvirus 8 (HHV8, also known as Kaposi's sarcoma [KS]-associated herpesvirus) has been implicated as an etiologic agent for KS, an angiogenic tumor composed of endothelial, inflammatory, and spindle cells. Here, we report that transgenic mice expressing the HHV8-encoded chemokine receptor (viral G protein-coupled receptor) within hematopoietic cells develop angioproliferative lesions in multiple organs that morphologically resemble KS lesions. These lesions are characterized by a spectrum of changes ranging from erythematous maculae to vascular tumors, by the presence of spindle and inflammatory cells, and by expression of vGPCR, CD34, and vascular endothelial growth factor. We conclude that vGPCR contributes to the development of the angioproliferative lesions observed in these mice and suggest that this chemokine receptor may play a role in the pathogenesis of KS in humans.

Animals↗

PubMed2000

Isolation and characterization of proteins that bind to galactose, lipopolysaccharide of Escherichia coli, and protein A of Staphylococcus aureus from the hemolymph of Tachypleus tridentatus.

In this study, we report the isolation and characterization of three novel hemolymph proteins that are believed to be involved in the innate immune response of horseshoe crabs, Tachypleus tridentatus. They include two closely related proteins, one that binds to the protein A of Staphylococcus aureus (PAP) and another that binds to the lipopolysaccharide of Escherichia coli (LBP). PAP binds specifically to staphylococcal protein A (SpA) with a K(D) of 3.86 x 10(-5) M, whereas LBP binds to lipopolysaccharide (LPS) with a K(D) of 1.03 x 10(-6) M. Both PAP and LBP are glycoproteins with an apparent molecular mass of about 40 kDa. N-terminal sequences of PAP and LBP showed 61.9 and 72.2% identity, respectively, to tachylectin-3, a lectin isolated from the amebocyte of T. tridentatus, previously characterized by its affinity to the O-antigen of LPS and blood group A antigen (Muta, T., and Iwanaga, S. (1996) Curr. Opin. Immunol. 8, 41-47). The third protein, a galactose-binding protein (GBP), was found to bind tightly to Sepharose CL-4B and could only be eluted from the column matrix with chaotropic agents, such as 4 M urea or 2 M guanidine hydrochloride. Further analysis indicated that GBP binds to D(+)-galactose with a K(D) of 2.47 x 10(-7) M. N-terminal sequence analysis showed that GBP shared a 50% identity with lectin L-6, identified in the granules of amebocyte of T. tridentatus. (Gokudan, S., Muta, T., Tsuda, R., Koori, K., Kawahara, T., Seki, N., Mizunoe, Y., Wai, S. N. , Iwanaga, S., and Kawabata, S. (1999) Proc. Natl. Acad. Sci. U. S. A. 96, 10086-10091). Lectin-L6 and tachylectin-3 are nonglycosylated intracellular proteins with about half the molecular mass of PAP, LBP, and GBP. GBP also binds to PAP and LBP with K(D) values of 1.25 x 10(-7) and 1.43 x 10(-8) M, respectively, and this binding is enhanced about 10-fold upon the addition of SpA and LPS to form the GBP.PAP.SpA and GBP.LBP.LPS complexes, respectively.

Amino Acid Sequence↗

PubMed2000

Accuracy of ultrasonography in the diagnosis of peritonitis compared with the clinical impression of the surgeon.

HYPOTHESIS: Peritonitis is a well-known indication for surgery, but its preoperative cause usually is not established. We hypothesize that abdominal ultrasonography is superior to the clinical impression of the surgeon in detecting the cause of peritonitis. DESIGN: A prospective case series. SETTING: A major university hospital in Taiwan, Republic of China. PATIENTS AND METHODS: One hundred two patients with a diagnosis of peritonitis admitted to the Department of Emergency Medicine, National Taiwan University Hospital, Taipei, were included in this study. All 102 patients underwent an abdominal ultrasonographic examination; and the ultrasonographic findings of these patients were classified into 2 categories: positive findings and normal screening results. The accuracy of clinical impression in detecting the cause of peritonitis was compared with the accuracy of abdominal ultrasonography. RESULTS: Ultrasonography and clinical impression accurately diagnosed the peritonitis in 85 (83.3%) and 52 (51.0%) of the patients, respectively. The difference between ultrasonography and clinical impression in the diagnosis of peritonitis was significant (P<.001). Among 45 patients without a preoperative clinical diagnosis, a diagnosis was made by ultrasonography for 32 (71%) of them. There were a total of 98 patients with positive ultrasonographic findings, and 4 patients had normal screening results. Of the 98 patients with positive ultrasonographic findings undergoing surgery, all had abdominal pathological characteristics. The 4 patients with normal screening results received nonoperative treatment. CONCLUSIONS: Ultrasonography is a more sensitive technique than clinical judgment in diagnosing peritonitis. Ultrasonography may be a useful diagnosing modality in patients with peritonitis in whom the clinical cause is unclear.

Clinical Competence↗

PubMed2000

Sonographic detection of delayed small bowel perforations after blunt abdominal trauma.

Isolated perforations of the small bowel resulting from blunt abdominal trauma are rare and difficult to diagnose because of their variable presentation, especially when their appearance is delayed. We report 2 such cases that were diagnosed by sonography and emphasize the usefulness of sonography in detecting bowel injuries after blunt abdominal trauma.

Abdominal Injuries↗

PubMed2000

Five-loop coil occlusion of patent ductus arteriosus prevents recurrence of shunt at follow-up.

Recent reports suggest reopening of the patent ductus arteriosus (PDA) after complete occlusion with three-loop Gianturco coils. We hypothesize that five-loop coils may produce a larger thrombus than three-loop coils, which will result in no or less probability of recanalization of PDA during follow-up. This study is designed to test this hypothesis. Follow-up echocardiographic and Doppler data of 30 patients who underwent five-loop coil occlusion of small to medium-sized PDA during a 33-month period ending December 1998 were examined. Thirty patients had no residual shunt on echo Doppler study on the day following the procedure and were followed for 6 to 30 months (median, 12) after coil implantation. At the last follow-up study, none of the patients had a residual shunt and left atrial size decreased. Careful pulsed, continuous wave, and color Doppler interrogation of left/main pulmonary artery junction and proximal descending aorta did not reveal any evidence for obstruction. The follow-up data suggest that complete occlusion of small- to medium-sized PDAs is feasible with five-loop coils without evidence for recanalization at a mean follow-up of 12 months. Much longer (2 to 5 years) follow-up data may be necessary to confirm these observations. We speculate that a greater degree of thrombosis is produced within the ductus by the five-loop coils, which in turn may be responsible for lack of shunt recurrence. We recommend use of five-loop instead of three-loop coils for transcatheter occlusion of small- to medium-sized PDAs.

Child↗

PubMed2000

Sonographic and pathologic findings in typical and atypical medullary carcinomas of the breast.

PURPOSE: We investigated whether there was a relationship between the sonographic and histologic appearances of medullary carcinomas of the breast to determine whether sonography is helpful in the differentiation of typical and atypical medullary carcinomas. METHODS: We retrospectively reviewed the histologic slides and sonograms of 20 patients who had been diagnosed with medullary carcinoma of the breast. We then classified the carcinomas as typical or atypical based on strict histologic criteria. We also evaluated the relationship between sonographic findings and the histologic reclassification. RESULTS: Eight (40%) of the 20 medullary carcinomas were classified as typical, and 12 (60%) were classified as atypical. On sonography, a smooth outline was visualized in 6 (75%) of the 8 typical medullary carcinomas but in none of the 12 atypical carcinomas. A jagged margin was sonographically visualized in 10 (83%) of the 12 atypical carcinomas, and a focal irregularity in the margin was visualized in 2 (17%) of the 12 atypical carcinomas. Four of the typical medullary carcinomas had posterior enhancement, and 9 of the atypical medullary carcinomas showed retrotumoral shadowing. The difference in tumor-margin regularity between typical and atypical medullary carcinomas was found to be statistically significant (p < 0.001) using the 2-tailed Fisher's exact test. CONCLUSIONS: To prevent overdiagnosis of medullary carcinoma, a thorough pathologic review of the entire tumor is recommended if sonography shows a jagged margin or a margin with focal irregularity.

Adult↗

PubMed2000

Methanosarcina mazei strain O1M9704, methanogen with novel tubule isolated from estuarine environment.

A new methanogenic isolate, designated as strain O1M9704 (=OCM 667), was isolated from the sediment of the estuarine environment in Eriln Shi, Taiwan. This strain grew on trimethylamine and methanol, but it did not catabolize H2-CO2, acetate, or formate. Cells grew optimally at 37 degrees C with 0.5% NaCl in neutral pH. The cells were stained Gram-negative, nonmotile, irregular coccus 0.3-0.6 microm in diameter. A comparison of 16S rDNA sequences phylogenetically related strain O1M9704 to Methanosarcina mazei. Gas vacuoles were observed both under phase contrast microscope and in thin sections in the electron microscope. Negative stain of electron micrographs showed a novel character of strain O1M9704. with tubule structure extended out of the cells. The tubule structure and gas vacuoles may benefit the adaptation of methanoarchaea in estuarine environment.

Culture Media↗