Biomedical subjects

M H Yang

Publications and source records attributed to M H Yang.

At least 37 records · Page 2Linked to original sources

PubMed2000

Venous gangrene in a patient with adenocarcinoma of the lung.

Cancer-related thromboembolism is a severe but not uncommon paraneoplastic syndrome in mucinous cancer patients. However, cancer-induced venous gangrene is extremely rare and has never been reported in the English literature. Here, we present a case of lung cancer complicated with venous gangrene of the left foot. An elevated serum anticardiolipin level was detected during hospitalization, but the patient's clinical condition stabilized after heparinization. We suggest that in cancer patients, an elevated serum anticardiolipin antibody level might be a warning sign of an impending thrombotic event and that low-molecular-weight heparin is a sensible choice in treating this kind of cancer-related thromboembolism.

Adenocarcinoma↗

PubMed2000

Single agent paclitaxel as a first-line therapy in advanced urothelial carcinoma: its efficacy and safety in patients even with pretreatment renal insufficiency.

BACKGROUND: Cisplatin-based chemotherapy is the mainstay of the treatment for advanced urothelial cancer, but patients with renal insufficiency before therapy are usually contraindicated to receiving platinum-based chemotherapy. Paclitaxel is one of the most promising agents against advanced urothelial carcinoma in recent trials and it can be easily tolerated even in patients with compromised renal function. We conducted a study in order to evaluate the efficacy and safety of paclitaxel as a first-line therapy in advanced urothelial carcinoma patients. METHODS: Thirteen advanced chemo-naive urothelial carcinoma patients with a median age of 71 years were studied, seven of them demonstrating renal insufficiency (pretreatment serum creatinine > or = 1.5 mg/dl). All 13 patients received a minimum of two cycles of paclitaxel 175 mg/m2, delivered by intravenous infusion for 3 h every 3 weeks. RESULTS: Four of the 13 patients responded to treatment, a response rate of 30.8%, with two of these achieving complete remission and two showing partial responses. The median overall survival period of all 13 patients was nine months (95% Cl: 6.51-11.49) and our study revealed a statistical tendency in the difference of median overall survival time between responders and non-responders (13 months versus 7.5 months, log-rank p = 0.038), although the number of cases was limited. The differences in response rate and median overall survival time, comparing patients with renal insufficiency and those with normal renal function, were not significant. Treatment-related toxicity was mild, with only two (15.4%) patients suffering from grade 3-4 leukopenia. No treatment-related mortality was noted. CONCLUSIONS: Single-agent paclitaxel can be used as a first-line therapy in advanced urothelial carcinoma patients, and is especially suitable for those with pretreatment renal insufficiency, since the antitumor activity is significant while toxicity is well tolerated.

Aged↗

PubMed2000

Islet cell hyperplasia of the pancreas presenting as hyperinsulinemic hypoglycemia in an adult.

A 72-year-old man who had suffered several episodes of syncope was diagnosed as having hyperinsulinemic hypoglycemia. Although imaging studies and percutaneous transhepatic portal venous sampling did not reveal the existence of any tumors in the pancreas, distal pancreatectomy was performed because the possibility of a small pancreatic endocrine tumor could not be completely rejected. External examination of the surgically removed pancreas did not reveal any tumors. Microscopically, the pancreas exhibited diffuse islet cell hyperplasia without nesidioblastosis. The patient remains euglycemic and has tolerated 24-hour fasting without any medication for a period of 10 months after the operation.

Aged↗

PubMed2000

Clinical experience in using polymerase chain reaction for rapid diagnosis of pulmonary tuberculosis.

BACKGROUND: Polymerase chain reaction (PCR) techniques have revolutionized the diagnosis of tuberculosis (TB). PCR has significantly improved the sensitivity and specificity of existing diagnostic methods. In this study, we report our experience using a modified IS6110-based nested PCR assay for rapid diagnosis of pulmonary TB. METHODS: A total of 327 respiratory specimens from 275 patients suspected of having pulmonary TB at Taipei Veterans General Hospital were tested using the nested PCR assay, acid-fast smear and culture for the presence of Mycobacterium tuberculosis complex (MTB). Nested PCR was performed with IS6110-based primers specific for MTB. We reviewed the medical records of patients and analyzed the clinical features. The PCR results were compared with the final clinical diagnosis. RESULTS: We identified MTB in 167 of 327 samples by the nested PCR assay. No non-tuberculous Mycobacterium (NTM) was identified among the clinical samples. Diagnosis by PCR took about 6 hours in this study. The sensitivity and specificity compared with culture were 94.7% and 100%, respectively for the smear-positive, culture-positive samples, and 76.7% and 98.6% for the smear-negative, culture-positive samples. The overall sensitivity, specificity, positive and negative predictive values, compared with culture results, were 91.7%, 98.6%, 98.8% and 90.6%, respectively. Two specimens positive by PCR and negative by culture were taken from patients on anti-TB drug therapy. These specimens were culture-positive before anti-TB drug therapy. After resolution of the discrepancies by studying the patients' clinical data, both specificity and positive predictive value reached 100%. CONCLUSIONS: The results indicated that this in-house nested PCR assay is a rapid and sensitive method for diagnosing pulmonary TB. It is also good for excluding infections caused by NTM.

Humans↗

PubMed2000

Effect of interleukin-15 and Flt3-ligand on natural killer cell expansion and activation: umbilical cord vs. adult peripheral blood mononuclear cells.

Expansion and activation of cord blood (CB) natural killer (NK) cells by cytokines might greatly benefit patients undergoing stem cell transplantation by increasing resistance against viral infections and providing graft-vs.-leukemia (GVL) effects through enhanced cytolytic abilities. We tested the ability of a recently cloned stem cell factor, Flt3-ligand (Flt3L), in combination with interleukin-15 (IL-15), to stimulate CB mononuclear cells (MNCs) to proliferate and differentiate into NK cells, in comparison with adult peripheral blood (APB) MNCs. Unstimulated CB MNCs had low NK and lymphokine-activated killer (LAK) activity compared with APB MNCs. A similar dose-dependent increase in NK and LAK activity and CD16/56 expression was found with IL-15 in CB and APB MNCs after 10 days of culture. The NK cytotoxicity (against K562 cells) of IL-15-treated CB MNCs was lower than that of corresponding APB MNCs, while IL-15-induced LAK activity (against Daudi cells) of CB MNCs was comparable to that of corresponding APB MNCs. IL-15 resulted in greater CD16/56 expression in CB MNCs compared with APB MNCs after 10 days of culture. Flt3L, alone or in combination with IL-15, had little effect on CD16/56 expression and cytotoxicity. Cytotoxic activities and CD16/56 expression did not alter after CD34 depletion of CB MNCs. We therefore concluded that CB NK cells could be greatly activated and expanded with IL-15, but not with Flt3L. The greater expression of CD16/56 induced by IL-15 in CB MNCs may originate from non-CD34+ NK progenitor cells.

Adult↗

PubMed2000

Immunophenotypic and genotypic characteristics of chronic myelogenous leukemia in blast crisis.

BACKGROUND: Chronic myelogenous leukemia (CML) may transform into blast crisis (BC) if not properly treated. Among patients with transformation, 20% to 30% will develop BC with lymphoid-associated antigens (Ly-BC), and the remaining cases with myeloid-associated antigens (My-BC) or with both (Mix-BC). In this study, we investigated the lineage of blast cells in CML-BC using immunophenotypic and genetic analyses and analyzed the prognostic significance of genotypic change in CML-BC. METHODS: Twenty-one patients with CML-BC diagnosed at the Taipei Veterans General Hospital from 1982 to 1992 were included. Immunophenotyping was done by using the avidin-biotin immunoperoxidase technique. Genetic analyses were carried out by using Southern Blot hybridization. The prognostic influence of genotypic change was analyzed. RESULTS: Thirteen patients (61.9%) expressed myeloid-associated antigens, one patient (4.8%) expressed megakaryoblast-associated antigens, four patients (19%) expressed B lymphoid-associated antigens and three patients (14.3%) expressed both myeloid and B lymphoid antigens. Clonal rearrangement of the immunoglobulin heavy chain (IgH) gene was found in six cases. Among them, four expressed B lymphoid markers only and two expressed both myeloid and B lymphoid markers. Patients with clonal IgH gene rearrangement tended to have a better response to chemotherapy (50% vs 8.3%, p = 0.08) and significantly longer survival (median survival, 5 months vs 3 months, p < 0.05) than did those with a germline configuration. CONCLUSIONS: Clonal rearrangement of the IgH gene was found mostly in cases of Ly-BC and Mix-BC. We found that CML-BC with clonal rearrangement of the IgH gene had a more favorable prognosis than in cases with a germline configuration.

Adolescent↗

PubMed2000

[EEG synchronization index spectrum: definition, calculation and the changes related to visual selective response].

OBJECTIVE: EEG synchronization is usually estimated in terms of coherence amplitude, but the estimation is with apparent uncertainty because of the poor resolution both in time and frequency. The purpose of this work is to surmount this problem. METHOD: A new definition of EEG synchronization index spectrum [SynI(f)] was developed basing on the distribution characteristics of EEG coherence phase which was calculated by a tested algorithm with 1 s and 1 Hz resolution. The basic feature and its changes during visual selective responses were calculated in 25 normal subjects. EEG signals were recorded from 9 locations in two conditions: looking at the central LED only(VC) and making switch response to the target LED flash signals (T) differentially (DR): switch to left or right for Ts from left (LVF) or right (RVF) visual field, repectively but making no response to the non-target ones (NT). RESULT: (1) The frequency dependency of SynI varied with brain location, e.g., SynI was higher in alpha range than others at frontal locations but the situation reversed at posterior locations. (2) The SynIs between midline and right brain locations were higher than that between mid line and left ones. (3) As compared with VC, SynI was increased in DR condition at central and posterior brain locations but not frontal ones, it happened mainly in 7-23 Hz at central locations but in 1-4 Hz at posterior ones. (4) The augmentation of SynI in DR was greater for T than for NT signals. CONCLUSION: The results indicated that the SynI(f) was meaningful for studying the frequency-spatial feature of EEG synchronization change among brain locations related to cognitive activities.

Aerospace Medicine↗

PubMed2000

Unsymmetrical response features of left and right brain to signals from left and right visual fields at different cognitive levels.

OBJECTIVE: To study the response characteristics of left and right brain to signals from left (LVF) and right (RVF) visual fields during cognitive activity. METHOD: ERPs at 9 locations to LVF and RVF signals were compared in 23 normal subjects in 3 task conditions: looking forward only (VC); making switch response to target signals (T) only (SR); making switch response to T differentially (DR). RESULT: (1) Significant difference in ERPs was found between that induced by LVF and RVF signals on left brain especially at frontal location (F5), which appeared as slow negative deflection induced by T and NT from RVF in SR and DR; (2) Condition-dependent unsymmetrical features between left and right brain were found: the slow potential at F5 was significantly more negative in T and contralateral spatial relation (i. e., left brain for RVF) but more positive in NT and ipsilateral relation than that at F6. CONCLUSION: Signals with psychological meaning in RVF might cause more psychological load as suggested by the results obtained in this study.

Adult↗

PubMed1999

TGF-beta1 inhibition of apoptosis through the transcriptional up-regulation of Bcl-X(L) in human monocytic leukemia U937 cells.

To characterize the TGF-beta1 response of monocytic leukemia cells, we analyzed the effects of TGF-beta1 on cell proliferation, differentiation, and apoptosis of human monoblastic U937 cells. Treatment of cells with TGF-beta1 in the absence of growth factors significantly enhanced cell viability. Flow cytometric analysis of DNA content and CD14 expression revealed that TGF-beta1 does not affect cell proliferation and differentiation. Consistent with these results was the finding that no transcriptional induction of Cdk inhibitors such as p21Waf1, p15Ink4b, and p27Kip1 was detected following TGF-beta1 treatment. Interestingly, however, pretreatment of TGF-beta1 significantly inhibited Fas-, DNA damage-, and growth factor deprivation-induced apoptosis. This antiapoptotic effect was totally abrogated by anti-TGF-beta1 antibody. Quantitative RT-PCR analysis demonstrated a dose- and time-dependent transcriptional up-regulation of Bcl-X(L), suggesting its implication in the TGF-1-mediated antiapoptotic pathway. We also observed elevated expression of c-Fos and PTEN/MMAC1. But, no detectable change was recognized in expression of c-Jun, Fas, Fadd, Fap-1, Bcl-2, and Bax. Taken together, our study shows that TGF-beta1 enhancement of cellular viability is associated with its antiapoptotic effect, which may result from the transcriptional up-regulation of Bcl-X(L).

Apoptosis↗

PubMed1999

Neurilemmoma of the mandible.

Intraosseous neurilemmoma is rare, representing less than 1% of benign primary bone tumors. The site most commonly involved is the mandible. We report on a neurilemmoma of the mandible in a 30-year-old woman. A panoramic radiograph of the mandible showed a well-defined unilocular osteolytic lesion with a thin uniform sclerotic margin located in the body of the mandible. The CT scan confirmed a well-defined osteolytic lesion with thinning of the cortex of the body of the left side of the mandible. Histologically, the lesion was a moderately cellular neoplasm with distinct palisading and numerous Verocay bodies. Ultrastructurally, the cytoplasmic membranes were distinct and coated by amorphous bands of basal lamina. Complete excision was achieved by removing the tumor from the inferior alveolar nerve.

Adult↗

PubMed1999

PFAPA syndrome (Periodic Fever, Aphthous stomatitis, Pharyngitis, Adenitis).

This paper aims to remind paediatric clinicians to suspect and confirm 'PFAPA' syndrome (Periodic Fever, Aphthous stomatitis, Pharyngitis and cervical Adenitis syndrome). We report two cases of PFAPA syndrome: a 3-year-old healthy boy with atopic rhinitis and a boy aged 8 years 5 months who simultaneously had lymphocytic vasculitis syndrome treated with immunosuppressive drugs. Both met Marshall's criteria. The literature regarding PFAPA syndrome was complied using a Medline search for articles published between 1963 and 1998 and we then reviewed the reference lists of the articles. The Medline search revealed 28 cases with available clinical manifestations, management and prognosis. Our study describes two additional cases. We divided the cases into typical (28 cases) and atypical (two cases) PFAPA syndrome. In typical PFAPA, the age of onset was less than 5 years in most cases and the patients presented 4.9 +/- 1.4 days of fever (100%), pharyngitis (89.3%), cervical adenitis (72.1%), stomatitis (71.4%), malaise (64.3%), headache (60.7%), abdominal pain (53.6%) and nausea/vomiting (17.9%). Afebrile intervals were 3.2 +/- 2.4 months and increased with age. The time from initial onset to final episode was 3 years 7 months +/- 3 years 6 months. The total number of episodes was 8.3 +/- 2.5 (range 6-14). Effective treatment included steroids, tonsillectomy/adenoidectomy and cimetidine. The general outcome was good. In atypical PFAPF, the clinical manifestations were similar to those of typical PFAPA except that the age of onset was more than 5 years, and life-threatening intestinal perforation happened once in a patient with underlying Fanconi's anaemia. It was concluded that typical PFAPA syndrome is benign and can be diagnosed by detailed history-taking and from physical findings during repeated febrile episodes with tests to rule out other periodic fever syndromes. A review of the literatures since the first report in 1987 has shown that typical PFAPA syndrome is not associated with significant long-term sequelae and has a good response to steroids. One patient with atypical PFAPA, who received low-dose steroids for over 1 year, developed intestinal perforation after an increment of the 7-day steroid dose. If an underlying problem requires long-term immunosuppressive medication, it is wiser to choose cimetidine rather than increasing the steroid dosage to resolve atypical PFAPA.

Azathioprine↗

PubMed1999

Primary alveolar soft part sarcoma of bone.

AIMS: Alveolar soft part sarcoma is a distinct, rare soft tissue tumour occurring primarily within the skeletal muscles or musculofascial planes in young adults. Primary involvement of bone is extremely rare. We report on six patients with alveolar soft part sarcoma occurring primarily in bone. METHODS AND RESULTS: Thorough clinical and radiographic examinations were done to rule out any other primary site. The patients were four women and two men aged 17-35 years (mean, 24.5 years). The primary site of the tumour was the femur in three patients, the ilium in one and the fibula in two. In one of the patients with fibular involvement, the tibia was also involved by direct extension. Of the long bone lesions, three were centred in the metaphysis and one in the diaphysis. Radiographically, all of the lesions demonstrated an osteolytic pattern of bone destruction with ill-defined margins and a wide zone of transition between the lesion and adjacent normal bone. Microscopically, all tumours showed the typical histological pattern of alveolar soft part sarcoma. Diastase-resistant, periodic acid-Schiff-positive crystalline structures were identified within the cytoplasm and confirmed ultrastructurally. Immunohistochemically, a keratin stain was negative in all cases; there was positive staining for MyoD1 in the cytoplasm but not the nuclei. Distant metastasis developed in four patients; one died. CONCLUSION: Alveolar soft part sarcoma arising in bone is extraordinarily rare but should be considered in the differential diagnosis of metastatic hypernephroma in a young patient.

Adolescent↗

PubMed1999

The adsorption protein genes of Xanthomonas campestris filamentous phages determining host specificity.

Gene III (gIII) of phiLf, a filamentous phage specifically infecting Xanthomonas campestris pv. campestris, was previously shown to encode a virion-associated protein (pIII) required for phage adsorption. In this study, the transcription start site for the gene and the N-terminal sequence of the protein were determined, resulting in the revision of the translation initiation site from the one previously predicted for this gene. For comparative study, the gIII of phiXv, a filamentous phage specifically infecting X. campestris pv. vesicatoria, was cloned and sequenced. The deduced amino acid sequences of these two pIIIs exhibit a high degree of identity in their C-terminal halves and possess the structural features typical of the adsorption proteins of filamentous phages: a signal sequence in the N terminus, a long glycine-rich region near the center, and a hydrophobic membrane anchorage domain in the C terminus. The regions between gIII and the upstream gVIII, 128 nucleotides in both phages, are larger than those of other filamentous phages. A hybrid phage of phiXv, consisting of the phiLf pIII and all the other components derived from phiXv, was able to infect X. campestris pv. campestris but not X. campestris pv. vesicatoria, indicating that gIII is the gene specifying host specificity and demonstrating the interchangeability of the pIIIs.

Amino Acid Sequence↗

PubMed1999

Adenosquamous carcinoma of the prostate.

An unusual adenosquamous carcinoma originating in the prostate of a 73-year-old man is described. The histological finding showed a well differentiated squamous cell carcinoma admixed in an adenocarcinomatous area. A transitional area of 2 carcinomatous elements was also noted. Seven months prior to the development of this lesion, a diagnosis of adenocarcinoma had been established by transurethral resection of the prostate and the patient had been treated with bilateral orchiectomy. This is the first case of adenosquamous carcinoma of the prostate reported in Korea. The pathogenesis and previous reports of this lesion will be discussed.

Aged↗

PubMed1999

A case with intrahepatic double cancer: hepatocellular carcinoma and cholangiocarcinoma associated with multiple von Meyenburg complexes.

Combined hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC) is sometimes found in resected livers, however, cases with double cancer of HCC and CC are very rare. As well, the rarity of CC arising in von Meyenburg complexes (VMCs) is appreciated. We report the case of a 74-year-old man found to have intrahepatic double cancer composed of well-differentiated HCC and CC which exhibited a histologic progression from VMCs to adenomatous lesions and CC. To our knowledge, this is the first case report published in the literature of a double HCC and CC associated with multiple VMCs. The pathogenesis and previous associated reports of these lesions are discussed.

Aged↗

PubMed1998

Urinary levels of inorganic and organic arsenic metabolites among residents in an arseniasis-hyperendemic area in Taiwan.

In order to elucidate whether urinary levels of inorganic and organic arsenic metabolites are associated with previous exposure to high-arsenic artesian well water, a total of 302 residents of age 30 yr or older were recruited from three arseniasis-hyperendemic villages in Taiwan. Most study subjects had stopped consuming high-arsenic artesian well water for more than 20 yr. The mean total arsenic (Ast) determined by inductively coupled plasma mass spectrometer (ICPMS) was 267.05 +/- 20.95 microg/L, and the mean level of inorganic arsenic and its metabolites (Asi) was 86.08 +/- 3.43 microg/L. In the multivariate analysis, urinary dimethylarsinic acid (DMA) levels were significantly inversely associated with age, with women exhibiting significantly lower urinary amounts of arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid (MMA), organic arsenic (Aso), and Ast compared to men. After adjustment for age and sex, previous cumulative arsenic exposure through consumption of artesian well water was significantly associated with elevated urinary levels of MMA and DMA, but not As(III) + As(V), Aso and Ast. In the multivariate analysis, the percentage of Aso in Ast was significantly higher in men than women, but this was not significantly associated with age. The percentage of As(III) + As(V) in Asi increased significantly with age, while the reverse was noted with DMA in Asi. Women had a significantly higher DMA percentage but lower As(III) + As(V) and MMA percentages in Asi than men. After adjustment for age and sex, the percentages of As(III) + As(V) in Asi were significantly inversely associated with previous arsenic exposure through consumption of artesian well water. Data suggested that women seem to possess a more efficient arsenic methylation capability than men, and aging diminishes this methylation capability; furthermore, the higher the cumulative arsenic exposure, the greater is the body burden of inorganic arsenic, mainly in the form of MMA and DMA.

Adult↗

PubMed1998

Mutational abrogation of the PTEN/MMAC1 gene in gastrointestinal polyps in patients with Cowden disease.

BACKGROUND & AIMS: To understand the molecular etiology of Cowden disease-associated gastrointestinal polyps, we analyzed the mutational status of PTEN/MMAC1, a recently identified Cowden disease gene located at 10q23, in gastric hamartomas, colonic adenoma, and juvenile polyps of 3 patients with Cowden disease. METHODS: Messenger RNA expression, gene deletion, and sequence alteration of PTEN/MMAC1 were evaluated by quantitative polymerease chain reaction (PCR), PCR-single-strand conformation polymorphism, and sequencing analysis. RESULTS: Germline missense mutation at codon 289 (AAA to GAA, Lys to Glu) and deletion of the wild-type allele were detected in the polyps of 2 patients with Cowden disease in the same family. Germline allelic deletion and transcriptional silencing of the remaining allele, probably caused by abnormal methylation, were also observed in a gastric hamartoma of 1 patient. CONCLUSIONS: The germline mutation and alteration of the remaining allele observed in this study strongly support that PTEN/MMAC1 functions as a tumor suppressor in Cowden disease. This study is the first to show that the mutational abrogation of PTEN/MMAC1 plays a causal role in the genesis of gastrointestinal polyps in Cowden disease, providing molecular genetic evidence that colonic adenoma, juvenile polyp, and gastric hamartoma could be included in the manifestations of Cowden disease.

Adolescent↗

PubMed1998

Detection of t(11;22)(q24;q12) translocation of Ewing's sarcoma in paraffin embedded tissue by nested reverse transcription-polymerase chain reaction.

Ewing's sarcoma is a poorly characterized malignant tumor with a relatively uniform histologic appearance, made up of densely packed small cells with round to oval nuclei, without distinct cell borders and without any structural differentiation. Often the diagnosis has to be made by exclusion. Recently, it has been made possible to identify characteristic chromosomal rearrangements associated with certain solid tumors. More than 85% of Ewing's sarcoma and peripheral neuroectodermal tumor present a specific t(11;22)(q24;q12) balanced translocation, resulting in the production of a novel chimerical EWS/FLI-1 message. Using oligonucleotide primers derived from EWS and FLI-1 complementary DNAs, we were able to use reverse transcription-polymerase chain reaction (RT-PCR) as a diagnostic tool. The described nested RT-PCR method as another supportive diagnostic method enables pathologists to differentiate small blue cell tumors not only to make correct diagnosis but also to investigate retrospective archival tumor samples, using formalin fixed paraffin embedded tissue as a source of RNA.

Chromosomes, Human, Pair 11↗