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Biomedical subjects

C H Hsiao

Publications and source records attributed to C H Hsiao.

At least 19 recordsLinked to original sources
PubMed2001

Recurrent cardiac myxoma with multiple distant metastasis and malignant change.

A 37 year-old female underwent open heart surgery for a left atrial myxoma. The post-operative course was uneventful and she was discharged two weeks later. She had regular monthly follow-up in the outpatient department until 10 months postoperatively when she was readmitted to the orthopedic ward for excision of a left ankle tumor. Two days after admission, she developed severe orthopnea. The initial diagnosis was heart failure, and she was transferred to the medical ward for treatment. Transthoracic and transesophageal echocardiography revealed a recurrent left atrial tumor. Because of acute obstruction of the mitral valve and deterioration of her condition, she underwent emergent open heart surgery. The recurrent atrial tumor was excised; histopathologic examination revealed a myxoid sarcoma. Multiple tumors were found on this admission, including a mass in the neck and in the left forearm; computed tomography revealed a brain tumor in the left posterior frontal lobe and a chest wall tumor. She died two months later. Recurrent cardiac myxoma with multiple distant metastasis may have a malignant potential. Because of the potential for tumor recurrence, long-term and regular follow-up is mandatory.

Adult↗
PubMed2000

Constructing a 3-D mesh model for electrical cardiac activity simulation.

The 3-D ventricle model in this study was reconstructed from a series of MRI torso cross-section data. We used a 3-D voxel array to represent the ventricle. As in cardiac simulations proposed by previous studies, the activation sequence and body surface ECG were simulated in this model. But to reduce the amount of elements in the model, so that the amount of parameters in the model can be handled numerically, we propose another approach to simulate cardiac activity. A mesh model was constructed on the closed surface formed by epicardiac and endocardiac surfaces of the ventricle. We propose a method to simulate the activation sequence on the epicardiac and endocardiac surfaces of the mesh model. As with the uniform double layer theorem, body surface ECG can be estimated in terms of epicardiac and endocardiac surface current source. Consequently, we can also generate ECG waveforms corresponding to this mesh simulation. Both the depolarization sequence and ECG simulated by the mesh model resemble those generated by the 3-D voxel model. However, the mesh model greatly simplified the process of ECG simulation. Both the simulation of depolarization and ECG estimation were expressed in terms of clear and simple mathematical representations. Consequently, we can analytically investigate the effects of the mesh model's parameters on the cardiac activation sequence and ECG. It could be a useful tool to numerically study the relation of ECG waveforms and electrical activity of the heart.

Computer Simulation↗
PubMed2000

Characterization of acute myeloid leukemia with MLL rearrangements--no increase in the incidence of coexpression of lymphoid-associated antigens on leukemic blasts.

MLL gene rearrangements are associated with coexpression of myeloid- and lymphoid-associated antigens on leukemic blasts and a dismal outcome in acute lymphoblastic leukemia (ALL). Whether the same conditions can apply to acute myeloid leukemia (AML) is not quite clear. Rearrangements of the MLL gene were analyzed on 113 patients with newly diagnosed de novo AML in a single institution. Sixteen (14%) of them showed rearranged bands by Southern blot analysis, including three (50%) of six infants, three (14%) of 21 children between 1 and 15 years and 10 (12%) of 86 adults. MLL rearrangements were not only detected in M5 (four of 12 patients, 33%) and M4 (six of 31, 19%) subtypes but also in other non-M4-M5 AML (six of 70, 9%), including M1, M2 and M7, but not M3 subtype. Seven patients had chromosomal abnormalities involving 11q23, but nine did not. The latter comprised three (6%) of 48 patients with normal karyotype, one with t(8;21), none with t(15;17), inv(16) or t(9;22), and four (15%) of 27 with cytogenetic aberrations other than those specific structural abnormalities. In contrast to ALL, AML patients with MLL rearrangements did not tend to coexpress lymphoid- and myeloid-associated antigens simultaneously on leukemic blasts and have similar outcome as those without the gene rearrangements.

Acute Disease↗
PubMed1999

Contact leukomelanosis induced by the leaves of Piper betle L. (Piperaceae): a clinical and histopathologic survey.

BACKGROUND: In April 1997, an unusual pigmentary disorder was noticed by dermatologists in Taiwan. All patients had a history of using facial dressings with steamed leaves of Piper betle L. (Piperaceae). OBJECTIVE: Our purpose was to clarify the evolution and the origin of this unique leukomelanosis. METHODS: Fifteen patients with an unusual pigmentary disorder, who visited our clinic in September and October 1997, were asked to complete a questionnaire designed to elicit the history related to the disorder. Eight of these 15 patients underwent skin biopsies: 6 on the mottled hyperpigmented area (group A) and 2 on the hypopigmented area (group B). All 8 specimens were prepared with hematoxylin-eosin, Masson-Fontana, and S-100 stains. RESULTS: The results of the questionnaire revealed that these patients had all experienced a temporary erythematous reaction in the first few days of the use of the facial dressing, and 9 of them also complained of an accompanying stinging sensation. A bleaching effect became noticeable approximately 1 week to 1 month later. Eight patients reported that the hyperpigmentation and confetti-like hypopigmentation occurred after overexposure to the sun. In both groups, histopathologic examination revealed some melanophages in the dermis. Masson-Fontana staining of specimens from group A showed local interspersed depigmentation and hyperpigmentation in the basal epidermis and pigmentary incontinence in the dermis. This picture was different from the homogeneous depigmentation within basal epidermis in specimens from group B. In both groups, S-100 staining was negative for melanocytes in the depigmented area. CONCLUSION: The clinical course and histopathologic findings suggest that the evolution of this pigmentary disorder can be divided into 3 stages. The first stage is the immediate bleaching stage, when an irritant reaction is usually conspicuous. The second stage consists of prominent hyperpigmentation visible both grossly and microscopically. The final stage is characterized by confetti-like depigmentation. It may be induced by chemicals in the betel leaves such as phenol, catechol, and benzene derivatives, perhaps through inhibition of melanin synthesis or melanocytotoxicity.

Adult↗
PubMed1999

Epstein-Barr virus-associated intravascular lymphomatosis within Kaposi's sarcoma in an AIDS patient.

Intravascular lymphomatosis (IL) is an unusual neoplasm characterized by multifocal proliferation of lymphoma cells exclusively within the blood vessels. We report here a patient with acquired immunodeficiency syndrome (AIDS) and disseminated Kaposi's sarcoma. A 233-bp amplification product of HHV-8 was detected in the DNA extracted from specimens of Kaposi's sarcoma at different sites by polymerase chain reaction (PCR). At autopsy, the vessels within the Kaposi's sarcoma were dilated and filled with atypical large mononuclear cells. No such feature was seen in the vessels of non-Kaposi's sarcomatous regions. Immunohistochemically, the spindle cells of Kaposi's sarcoma were positive for CD31 (endothelial cell marker). The intravascular tumor cells were positive for CD45 (leukocyte common antigen) but negative for others, including chloroacetate esterase, CD45-RO (UCHL-1, Pan-T), CD3, CD43, CD20 (L26, Pan-B), CD30 (Ki-1), immunoglobulin heavy chains and light chains, CD56 (natural killer cell antigen), and CD31. Monoclonal rearrangement of immunoglobulin heavy chain gene was detected in the DNA extracts from fresh tissue of Kaposi's sarcoma by PCR, which indicated that the lymphoma cells within the Kaposi's sarcoma were of monoclonal B cell origin. In situ hybridization revealed that EBER-1 transcripts were present in the lymphoma cells of IL but not in the spindle cells of Kaposi's sarcoma. To the authors' best knowledge, this is the first instance of IL in an AIDS patient with direct evidence of EBV association.

Biomarkers, Tumor↗
PubMed1999

Merkel cell carcinoma and chronic arsenicism.

Arsenic is a well-documented human carcinogen. Bowen's disease, squamous cell carcinoma, and basal cell carcinoma are the most common skin cancers found in patients exposed to arsenic over the long term. Merkel cell carcinoma has been documented in Taiwanese patients who resided in an endemic area of black foot disease, another condition found in patients with chronic arsenicism. We collected all cases of Merkel cell carcinoma diagnosed at two medical centers in Taiwan (N = 11) to find a possible association between chronic arsenicism and Merkel cell carcinoma. In our study 6 of the 11 patients were residents of the endemic areas for chronic arsenicism.

Aged↗
PubMed1998

Effervescent gallbladder: sonographic findings in emphysematous cholecystitis.

We report a case of emphysematous cholecystitis with the sonographic appearance of an "effervescent gallbladder"--a large amount of gas bubbles rising like bubbles in a glass of champagne from the dependent part of the gallbladder and floating to the nondependent part. The etiology of this finding was acute obstruction of the distal common bile duct by a stone and purulent cholangitis. Short-term follow-up sonography is important to confirm the diagnosis of cholecystitis.

Cholangitis↗
PubMed1998

The cycloplegic effects of cyclopentolate and tropicamide on myopic children.

Thirty-seven myopic children were given either 1-2 drops of 1% cyclopentolate or 1% tropicamide twice with 5 min intervals to evaluate the time course and maximal cycloplegic effect of both agents. The other fifteen subjects were given 1% tropicamide initially, then 1% cyclopentolate given after 30 min of maximal effect of tropicamide appeared to evaluate whether the effect of cyclopentolate was superior to tropicamide. Cycloplegic refraction was measured with an auto-refractometer (Topcon RK-3000) before drug delivery and every 15 min thereafter, for 90 min. The maximal cycloplegic effect of cyclopentolate was around 45 min, then it remained stable until 90 min after the last instillation. The effect of tropicamide was faster than that of cyclopentolate. It was around 30 min, then it stabilized until 75 min. The extra effect of cyclopentolate over tropicamide was minimal (only -0.1D). The power of cornea and astigmatism were not affected by either agent. However, a big variation in astigmatism was noted during the course, especially with cyclopentolate. This study suggests that 1% tropicamide should be a good agent for routine refractive status checking on myopic children.

Accommodation, Ocular↗
PubMed1998

Intrascleral dissemination of infectious scleritis following pterygium excision.

AIMS: To assess the clinical pictures, possible pathogenesis, management, and therapy of patients with infectious scleritis associated with multifocal scleral abscesses following pterygium excision. METHODS: The records of patients with infectious scleritis after pterygium excision who developed multifocal scleral abscesses presenting from 1988 to the end of 1995 were reviewed. Early culture of abscesses was performed, and topical, systemic antimicrobials, or both were given to all patients. Fourteen eyes were operated on in addition to antimicrobial treatment. RESULTS: The initial culture reports of scleral ulcers identified Pseudomonas species in 12 of these 18 patients, Aspergillus in one, Mycobacterium fortuitum in one, and mixed organisms in four. Subsequent abscess cultures were taken from 15 of the infected eyes, and revealed the same organism as the initial culture in 12. Associated complications included four serous retinal detachments, three choroidal detachments, two double detachments, five complicated cataracts, and four recurrences of the initial infection. Four eyes required eventual enucleation and 11 eyes regained useful vision. CONCLUSIONS: With subsequent abscess cultures proving to be the same organism as found in the initial ulcer, the abscess formation appears to represent intrascleral dissemination. Early diagnosis and appropriate, prolonged topical plus systemic antimicrobial treatment are essential to halt the progression of such severe infections.

Abscess↗
PubMed1997

Autopsy findings on patients with AIDS in Taiwan.

At National Taiwan University Hospital, from 1986 to 1996, autopsies were performed on 16 patients with acquired immunodeficiency syndrome. There were 15 men and 1 woman. Fourteen of these male patients had contracted the disease as a result of sexual practice, among which 9 were homosexual, 1 was bisexual and 4 were heterosexual. One of the patients had become infected by sharing a syringe during intravenous drug use. The female was a sex worker. Among these patients, only 2 had been tested for HIV before developing AIDS. On autopsy, lymphoid depletion and thymus atrophy were found in all patients. Testicular atrophy was noted in all the male patients. Three patients died of malignant lymphoma. Twelve patients died of opportunistic infections and 1 committed suicide. The initial opportunistic infection was usually oral candidiasis. Pneumocystis carinii pneumonia (PCP) was the most common opportunistic infection developed in the early stage while cytomegalovirus (CMV) infection was the most common one found in the late stage. Mycobacterium infection had developed in 8 patients. Six patients had disseminated Kaposi's sarcoma (KS) and 4 of them were homosexual. In 4 patients, biopsy specimens were proved to have KS associated viral (HHV-8) genome. Malignant lymphoma was found in 4 cases, all were of high grade B cell type. Epstein-Barr virus (EBV) encoding small RNA (EBER1) was demonstrated in all the lymphomas. In conclusion, (1) the prevalence of tuberculosis (38%) in patients with AIDS in Taiwan is high; (2) the most common opportunistic infections in this series are candidiasis, PCP and CMV infections; (3) the incidence of AIDS related non-Hodgkin's lymphoma in Taiwan has increased since 1995.

AIDS-Related Opportunistic Infections↗
PubMed1997

Immunohistochemical and ultrastructural study of malignant plasmacytoid myoepithelioma of the maxillary sinus.

Myoepithelioma is a rare salivary gland tumor which is composed exclusively of myoepithelial cells. Histologically, it can be divided into three cell types: spindle, plasmacytoid and mixed type. Malignant myoepithelioma is characterized by invasive growth. In March 1995, a 60-year-old man presented with a left cheek tumor which he had first noted 2 years previously. Computed tomography revealed a large expansile tumor in the maxillary sinus with invasion into the surrounding soft tissue. Partial resection of the tumor was performed because of extensive involvement of the surrounding tissue. The patient died due to spread to the brain 5 months after surgery. Histologically, the tumor was composed exclusively of plasmacytoid cells, with bone destruction. Immunohistochemically, these cells were negative for immunoglobulin light chains (kappa and lambda) and heavy chains (Ig G, A, M) but positive for S-100, cytokeratin, actin and vimentin.Ultrastructurally, the tumor cells contained numerous randomly oriented actin-like microfilaments in the cytoplasm, and had desmosomes on the cell membrane. Malignant plasmacytoid myoepithelioma of the maxillary sinus was diagnosed. In addition to our case, only five cases of pure plasmacytoid myoepithelioma have been reported. Plasmacytoid myoepithelioma tends to occur in the minor salivary glands and has more aggressive behavior than spindle cell myoepithelioma. Morphologically, it is very difficult to differentiate plasmacytoid myoepithelioma from plasmacytoma and immunohistochemical staining is necessary to make a correct diagnosis.

Actins↗
PubMed1996

Angiocentric T-cell lymphoma of the intestine: a distinct etiology of ischemic bowel disease.

BACKGROUND & AIMS: Bowel ischemia and perforation is an infrequent but ominous event in patients with malignant lymphoma. The underlying pathogenesis of this association remains to be clarified in most cases. Seven unusual cases of angiocentric T-cell lymphoma of the intestine presenting with bowel ischemia or perforation are reported. Their clinicopathologic features were analyzed. METHODS: Clinical records and histopathology were reviewed. Immunophenotypic studies and EBER1 in situ hybridization for Epstein-Barr virus were performed. RESULTS: All patients (3 men and 4 women; mean age, 42 years) presented with acute abdominal pain, bloody stool, or bowel perforation. The intestinal lesions were ulcerated and transmurally necrotic or gangrenous. The angiodestruction of the tumor cells appeared to be responsible for the presenting bowel ischemia. The neoplastic cells expressed a pan-T-cell antigen CD45RO; 4 of them contained Epstein-Barr virus transcripts EBER1. The prognosis was grave; 6 patients died within 3 months of onset. CONCLUSIONS: Intestinal angiocentric T-cell lymphoma represents a distinct etiology of bowel ischemia. The condition should be taken into consideration, particularly in young adults with ischemic bowel disease.

Adult↗