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Biomedical subjects

C K Ho

Publications and source records attributed to C K Ho.

At least 19 recordsLinked to original sources
PubMed1996

Cathepsin D and epidermal growth factor receptor immunohistochemistry does not predict recurrence of prostate cancer in patients undergoing radical prostatectomy.

PURPOSE: We determined if immunohistochemical expression of the epidermal growth factor receptor and cathepsin D in the primary tumor was of prognostic value in clinically localized prostate cancer after radical prostatectomy. MATERIALS AND METHODS: Immunohistochemical staining for epidermal growth factor receptor and cathepsin D was performed on 105 radical prostatectomy specimens from 2 academic centers. The epidermal growth factor receptor and cathepsin D expressions were graded using H scoring by an experienced pathologist blinded to other patient data, and compared with age, grade, stage, race and initial serologic (prostate specific antigen) recurrence. Univariate and multivariate statistical testing was performed. RESULTS: Immunohistochemically detectable epidermal growth factor receptor and cathepsin D expression was not correlated to age, race, stage or Gleason grade. In univariate and multivariate testing epidermal growth factor receptor and cathepsin D were not prognostic markers for disease progression following radical prostatectomy. CONCLUSIONS: Immunohistochemical analysis of the biomarkers cathepsin D and epidermal growth factor receptor in radical prostatectomy specimens does not predict disease recurrence. Further biological marker study is needed in clinically localized prostate cancer.

Aged↗
PubMed1995

Effect of lymphocytes on the production of granulomonopoietic enhancing factor by fully mature macrophages.

The granulomonopoietic enhancing factor (GM-EF) is a novel myelopoietic regulator produced by human monocyte-derived lipid-containing macrophages (MDLMs). In the present study, we examined the effect of lymphocytes on GM-EF production by preincubation of MDLMs with various preparations of lymphocyte subpopulations in cell-mixed and in double agar layer cultures. Our results showed that a cell concentration-dependent suppression of GM-EF production was noted in cultures with mitogen-activated T cells, and mitogen-activated/resting B cells, while those containing resting T cells had no such effect. Thus, GM-EF production in the presence of 1 x 10(5)/ml activated T cells or activated/resting B cells was greatly reduced to 5% or 20%, respectively. The lymphocyte-induced suppression was evident in both cell-mixed and double layer cultures, implying that the effector cells might exert their influences via mediators. Assay for cytokine activity revealed that a high level (648.2-685.2 pg/ml) of tumor necrosis factor-alpha (TNF-alpha) was found in MDLM cultures with resting/activated B cells, and in those with activated T cells high levels of both TNF-alpha (510.5 pg/ml) and interferon-gamma (IFN-gamma) (321.3 pg/ml) could be detected, whereas in cultures with MDLMs and/or resting T cells, these cytokines were not measurable. Treatment of MDLMs with either recombinant (r) TNF-alpha or rIFN-gamma invariably resulted in a dose-dependent decrease in GM-EF production with intense suppression at doses between 400-800 U/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

B-Lymphocytes↗
PubMed1995

Establishment of an occupational diseases surveillance system to monitor blood lead levels in Taiwan.

BACKGROUND: Occupational diseases share many common characteristics with infectious diseases. However, the successful approach of using surveillance systems to eradicate infectious diseases has never been applied to the control and prevention of occupational diseases. METHODS: On the basis of a nationwide survey of blood lead levels in the general population in Taiwan, we (the Ministry of Health, Taiwan) have developed an obligatory surveillance system for blood lead. RESULTS: This government-administered system, which uses laboratory data as its source of information, enrolls all workers whose blood lead level exceeds regulation points (40 microgram/dl for men and 30 micrograms/dl for women). A Group of Health Promotion of Lead-using Workers (GHPLW) has been organized to be responsible for conducting epidemiological investigations to locate exposure sources in the workplace and to improve the working environment of cases and other workers with the same exposure. CONCLUSIONS: We emphasize that the accomplishment of the GHPLW's task depends not only on "curing" the case, but also on eradicating the lead exposure source and decreasing the blood lead level of workers in the workplace during long-term follow-up. The system aims to upgrade occupational disease control to the stage of specific prevention and health promotion. The establishment of this system is a historic step in industrial hygiene and occupational disease prevention in Taiwan.

Female↗
PubMed1995

Production of a monoclonal antibody to an antigen present on both trophoblasts and leukocytes.

In the present study, we report the establishment of a monoclonal antibody (Mab) designated F10 that recognized an antigen commonly shared by human trophoblasts and leucocytes. F10 MAb was obtained using cell membrane components from a trophoblast cell line HT as immunogen. Based on immunochemical studies, the F10 reactive antigen (F10-Ag) could be located on both villous and nonvillous trophoblasts from early and term placental tissues and on all trophoblastic cell lines. In addition, flow cytometry revealed that most ( > 95%) peripheral blood lymphocytes, monocytes, as well as polymorphonuclear leukocytes (PMN) were positively stained with F10 MAb. Immunoblotting with F10 MAb identified two protein bands with apparent molecular mass of 62 and 56 kDa. Furthermore, the antigens were glycoproteins and were glycosylated via the O-linkage. Scatchard plot analyses of the binding data between 125I-labeled MAb F10 IgG and HT cells revealed a single class of F10 binding sites with an apparent dissociation constant (Kd) of 10.54 +/- 2.03 pM and maximum binding-site (Bmax) value of 2.1 +/- 0.11 x 10(6) sites per cell. We suggest that F10 may be useful for the identification of a novel epitope that is commonly shared by all trophoblasts and leukocytes and such an epitope may be potentially active in maternal-fetal interactions.

Antibodies, Monoclonal↗
PubMed1995

Some new insights into bladder function in infancy.

OBJECTIVES: To evaluate normal bladder function and micturition patterns in infants. PATIENTS, SUBJECTS AND METHODS: Twenty-one infants (16 boys, five girls; mean age 5.9 months) with no lower urinary tract pathology underwent natural filling cystometry. Micturition patterns were also observed simultaneously with polysomnography in 26 healthy neonates (16 boys, 10 girls; mean age 7.4 days). RESULTS: In infants, cystometry showed (95% CI) a capacity of 42-53 mL, a maximum rise in detrusor pressure during voiding of 95-120 cmH2O and a voiding efficiency (voided volume/capacity) of 0.86-0.91. On micturition, urinary flow was discoordinated from peak detrusor pressures in 10 infants. Detrusor instability occurred in one of 21 infants. Micturition was observed only during wakefulness or on arousal from sleep. In neonates, 17 of 61 recorded voids (28%) were during full wakefulness and 44 (72%) during arousal from sleep. Notably, none of the recorded voids occurred during quiet sleep. CONCLUSIONS: The normal infant's bladder was stable and emptied almost completely. Voiding with incomplete co-ordination between detrusor contraction and urinary sphincter relaxation could be normal. Micturition never occurred during quiet sleep. There was cortical arousal in response to a full bladder even in new-born infants. This contradicts the traditional concept of a totally uninhibited bladder in infancy. There are potential implications for the management of children with nocturnal enuresis.

Female↗
PubMed1994

Effect of arginase on splenic killer cell activity in patients with gastric cancer.

Arginase has been detected in high levels in gastric cancer tissues. The effect of arginase on the activities of splenic natural killer (NK) cell, phytohemagglutinin activated killer (PAK) cell, and interleukin-2 activated killer (LAK) cell in patients with gastric cancer (N = 12) was evaluated in vitro. These activities in patients (N = 10) with trauma and benign lesions were used as control. The splenic NK and PAK cell activities in patients with gastric cancer were significantly lower than in the controls (P < 0.05), whereas LAK cell activity did not have significant difference. Arginase inhibited all splenic killer cell activities to a similar degree between patients with gastric cancer and the controls. The inhibition was dose-related. These data suggest that arginase may play a positive role in the spread of gastric cancer cells. However, LAK may be a potential approach of immunoadoptive therapy in the future.

Arginase↗
PubMed1994

Thymic hyperplasia in newly diagnosed testicular germ cell tumors.

Thymic hyperplasia has been reported as a rebound phenomenon in children and young people, most commonly following chemotherapy for cancer. Although thymic hyperplasia has been documented in testis cancer patients after chemotherapy, to our knowledge it has not previously been reported in newly diagnosed cases before systemic therapy. A retrospective review of 362 testicular germ cell tumor patients treated at a single tertiary care center between January 1, 1980 and August 1, 1993 was performed, with special review of 221 who underwent computerized tomography staging of the chest. Thymic hyperplasia was detected in 4 of the 221 patients (1.8%) including 3 of 100 (3.0%) with seminoma and 1 of 121 (0.8%) with nonseminoma. All 4 patients had low stage (I or IIa) disease with a delay in diagnosis (5 to 24 weeks) and thymic hyperplasia was discovered at staging evaluation 18 to 37 days after orchiectomy but before other cancer therapy was administered. Of the 4 patients 2 underwent thymectomy, revealing histological thymic rebound hyperplasia. All 4 patients had no evidence of recurrence at 1 to 54 months after treatment. In addition to the well known post-chemotherapy phenomenon, thymic hyperplasia may also occur in nonsystemically treated, newly diagnosed testicular cancer patients. An anterior mediastinal mass in an otherwise low stage newly diagnosed testicular cancer patient may represent thymic hyperplasia and not necessarily metastatic disease.

Adult↗
PubMed1994

Immunohistologic detection of prostate cancer pelvic lymph node micrometastases: correlation to preoperative serum prostate-specific antigen.

OBJECTIVE: To test the hypothesis that prostate cancer lymph node (LN) micrometastases, undetected by standard histology, might be found using sensitive immunohistologic methods and may correlate to preoperative prostate-specific antigen (PSA) levels. METHOD: Archival paraffin blocks of pelvic lymphadenectomy specimens from radical prostatectomy were blindly submitted for immunostaining using pan-cytokeratin monoclonal antibody SB-3, as well as antibodies directed against PSA. Automated immunostaining was performed on a Ventana Medical Systems 320 immunostainer. As a positive control, 7 cases with known nodal metastases by standard histology were blindly analyzed and all has detectable micrometastases by this methodology. RESULTS: For 13 patients with PSA < 10.1 (8%) had LN micrometastases detected. For 10 patients with PSA between 10 and 20 and for 9 patients with PSA > 20, no occult metastases were detected. We did find previously undetected prostate cancer (CaP) LN micrometastases in 1 of 32 (3%) clinically localized prostate cancer patients who had undergone radical prostatectomy. In many LNs, cytokeratin stains cross-reacted and stained individual plasma cells, whereas in the positive metastatic case, a cluster/nest of CaP cells were reactive. To the unfamiliar observer, the pitfall of false-positive results because of nonspecific cytokeratin staining must be considered. These results are in exact agreement with another recent study which also found only a 3 percent incidence of unsuspected pelvic lymph node micrometastases in clinically localized CaP utilizing similar methods. CONCLUSIONS: Our hypothesis was not substantiated: LN micrometastases were uncommon and did not correlate to serum PSA. Unlike studies with breast cancer, occult micrometastatic nodal disease not appreciated by standard methods appears to be uncommon in clinically localized prostatic carcinoma.

Humans↗
PubMed1994

Narcolepsy in Hong Kong Chinese--a preliminary experience.

BACKGROUND: Narcolepsy is a sleep disorder of unknown aetiology. Despite the widely reported strong association with HLA DR2 among different ethnic groups and their varying prevalence rates, there has never been any series of laboratory documented narcolepsy in Chinese. AIMS: To report the preliminary experience with Chinese narcoleptic patients and their HLA typing. METHODS: The records of 342 patients who presented to our sleep laboratory for various sleep problems from 1986 to 1992 were examined. Both clinical and polysomnographic data were analysed. The criteria for a diagnosis of narcolepsy is based on shortened mean sleep latency of less than 5 minutes and presence of rapid eye movement (REM) sleep in two or more of the five 20-minute naps during multiple sleep latency test (MSLT). RESULTS: There were five narcoleptic patients documented resulting in an overall laboratory prevalence of 1.5% or 2.3% of patients presenting with hypersomnia. All patients were HLA DR2 positive. CONCLUSION: There is 100% association with HLA DR2 in Hong Kong Chinese narcoleptic patients. Based on the laboratory prevalence, the prevalence rate of narcolepsy among Hong Kong Chinese population is estimated to be within the range of four in 10,000 to one in 100,000.

Adolescent↗
PubMed1994

A patient with coexisting narcolepsy and morbid jealousy showing favourable response to fluoxetine.

A 37 year old Chinese man suffered from coexisting narcolepsy and morbid jealousy which were precipitated by head injury 5 years previously. Fluoxetine 20 mg/day reduced his narcoleptic symptoms and morbid jealousy but not his sleepiness. On defaulting treatment, the patient's symptoms and marital problem recurred. A common central serotonin disturbance might be involved in mediating the sleep disorder and associated psychopathology.

Accidents, Traffic↗
PubMed1994

Measles--an experience in Sandakan Hospital, Sabah, 1990.

A descriptive study of 143 cases of clinically diagnosed measles in patients under the age of 12 years admitted to the Duchess of Kent Hospital, Sandakan, Sabah, during the year 1990 was carried out. The median age of the patients was one year and 13.3% of the cases were between the ages of 6 and 9 months. The male to female ratio was 1.3:1. The majority of the cases (85.3%) were not immunised against measles while 60.0% of the cases were malnourished. Most of the cases (86.0%) had at least one complication with 32.9% of the cases having more than one complications. The main complications were pneumonia (74.1%) and diarrhea (38.5%). Other complications were convulsions, otitis media and corneal ulceration/scarring. A case of pneumonia with mediastinal emphysema and subcutaneous emphysema was noted. The case fatality rate was 1.4% while blindness was the long term morbidity in 1.4% of the cases. Measles remains an important cause of morbidity in children in Sabah.

Borneo↗
PubMed1994

Direct detection of the intracellular formation of carboxyphosphamides using nuclear magnetic resonance spectroscopy.

31P nuclear magnetic resonance (NMR) spectroscopy was used in conjunction with cell perfusion techniques to monitor the intracellular chemistry of the cyclophosphamide (CP, CAS 6055-19-2) metabolites 4-hydroxy-cyclophosphamide (4-HO-CP) and aldophosphamide (AP) in U937 human histiocytic (CP-sensitive) and K562 human erythroleukemia (CP-resistant) cells. Similar experiments were carried out using the ifosfamide (IF, CAS3778-73-2) metabolites 4-hydroxyifosfamide (4-HO-IF) and aldoifosfamide (AIF). The hydroxy and aldehydic metabolites were generated by the triphenylphosphine reduction of 4-hydroperoxycyclophosphamide (4-HO2-CP) or 4-hydroperoxyifosfamide (4-HO2-IF) or by a spontaneous elimination/addition reaction involving water and 4-thiocyclophosphamide analogs 4-(2-hydroxyethyl) thiocyclophosphamide (4-ESCP) or mafosfamide. Cell death resulting from 4-HO-CP/AP perfusions was mimicked by perfusion with acrolein or an acrolein producing but non-alkylating, dechloro-CP analog. Acrolein toxicity was minimized by the presence of 2-mercaptoethanol or mesna (sodium 2-mercaptoethanesulfonate) in perfusion solutions as well as by fractional dose drug perfusions (sequential 2.5-3.0 h perfusions separated by cell washes with drug-free medium). The intracellular half-life for phosphoramide mustard (PM) at an intracellular pH value of 7.1 +/- 0.1 and an ambient probe temperature of 23 +/- 1 degree C in U937 cells was 2.1 h [k = (5.4 +/- 0.3) x 10(-3) min-1] and in K562 cells was 3.1 h [k = (3.7 +/- 0.4) x 10(-3) min-1]. Similar half-lives (2-4 h) were determined for intracellular isophosphoramide mustard (IPM). Fractional dose perfusion of U937 or K562 cells with 1.5 mmol/l 4-HO-CP/AP (generated from 4-HO2-CP) and 0.3 mmol/l mesna allowed for the observation of intracellular carboxyphosphamide (CBP); CBP was formed in higher concentrations in the CP-resistant K562 cells. Similar results were obtained using 4-ESCP and mafosfamide as sources of 4-HO-CP/AP. Identification of CBP was based on chemical shift, chemical stability, and membrane permeability studies of synthetic CBP. Concentrations of carboxyifosfamide (CBIF) formed in K562 cells were also greater than that in U937 cells.

Acrolein↗
PubMed1993

Synchronous bilateral testis tumor: mixed germ cell and theca cell tumors.

Synchronous bilateral testis tumors of different histologic types are rare. All previous cases have demonstrated germ cell tumors on both sides. The simultaneous appearance of a germ cell tumor and a contralateral non-germ cell tumor has not been reported. We herein report a thirty-four-year-old man who presented with a mixed non-seminomatous germ cell tumor of the left testis and theca cell tumor of the right testis.

Adult↗
PubMed1993

Clinical and polygraphic characteristics of patients with respiratory dyskinesia.

Respiratory dyskinesia is characterized by irregularity in rate, rhythm and depth of breathing. This study reports on the clinical features of 11 patients with respiratory dyskinesia identified from a mental hospital in Hong Kong, together with the results of the 24-hour polygraphic recording of seven patients. Virtually all patients with respiratory dyskinesia had tardive dyskinesia. However, the condition was missed or misdiagnosed in all cases by the case psychiatrists. The respiratory irregularity persisted for most of the day and only disappeared when patients took a prolonged rest or fell asleep. A standardised clinical examination for respiratory dyskinesia is proposed.

Adult↗
PubMed1993

Cell source and biological characteristics of murine bone marrow-derived colony-promoting activity.

A murine colony-promoting activity (CPA) was found in the supernatants of Dexter long-term bone marrow cultures (LTBMC). This activity itself failed to stimulate in vitro granulocyte-macrophage colony (CFU-GM) formation but could increase the number of colonies induced by colony-stimulating factors (CSFs). CPA was produced by the adherent stromal cells but not by the nonadherent cells. No CPA could be detected in cultures of pure marrow fibroblasts, nor was it secreted by the stromal cells following macrophage depletion. In contrast, a large amount of CPA was found in cultures of isolated macrophages, suggesting that marrow macrophages may be the main cell source of CPA. Although colony formation was augmented by adding CPA in combination with various CSFs, the colony type induced by CPA plus CSF was no different from that of CSF alone. Preincubation of bone marrow (BM) cells with CPA at 37 degrees C for 24 hours before using in clonal culture assay resulted in a marked colony enhancement. Furthermore, colony formation by 5-fluorouracil (5-FU)-treated marrow cells could be induced by granulocyte-macrophage (GM)-CSF plus CPA but not by GM-CSF alone. These results suggest that CPA may act on early developing hematopoietic stem cells to induce them to differentiate into more mature myeloid progenitor cells capable of responding to CSF stimulation. CPA was nondialyzable and stable under heat (56 degrees C for 30 minutes) and freeze/thawing (3 times). Its activity was acid-labile (pH 2.0) but relatively alkaline-resistant (pH 11.0). When treated with enzymes, CPA was sensitive to trypsin and bacterial protease but not to neuraminidase. In addition, the activity of CPA could be abrogated by anti-CPA antiserum but remained unchanged after treatment with antibodies to other murine hematopoietic synergizing/stimulating factors, including interleukin-1 (IL-1), IL-3, IL-4, IL-6, and stem cell factor (SCF).

Animals↗
PubMed1993

Asbestos related pleural plaques in retired boiler room workers.

Occupational disease is often underestimated and only a few formal reports have been published in Taiwan. This study reports of a group of workers with asbestos-induced-disease, pleural plaque in Taiwan. Pleural plaque is a marker of exposure to asbestos. The disease was found in chest radiographs of five boiler room workers in a sugar refining factory. The chest radiographs of 248 current workers in that plant were reviewed, and none of them was found to have pleural plaques. The storage of asbestos and the long-time use of mixed asbestos cement for insulation of the inner wall of the stove and pipes were found in the factory. The authors believe that the pleural plaques might be resulted from occupational exposure to asbestos. It is suggested that the use of asbestos should be prohibited, step by step, and regular follow-up of the workers with an asbestos exposure history is required.

Aged↗