Biomedical subjects

J C Ho

Publications and source records attributed to J C Ho.

At least 19 recordsLinked to original sources

PubMed2006

Disturbance of systemic antioxidant profile in nonsmall cell lung carcinoma.

The present study aimed to determine the alterations of antioxidant activities in erythrocytes from patients with nonsmall cell lung carcinoma (NSCLC). A comparative study of the systemic antioxidant activities in red blood cell lysate from subjects with NSCLC and healthy control subjects was conducted. The antioxidants catalase, superoxide dismutase (SOD) and glutathione peroxidase (GPx) were measured using chemical kinetic reactions under spectrophotometry. In total, 189 cases of mostly advanced-stage IIIB or stage IV NSCLC and 202 healthy controls were studied. In subjects with lung cancer, there was similar catalase activity, lower SOD activity (median (interquartile range) 13.4 (9.0-27.2) versus 48.7 (27.0-64.3) U x (ghaemoglobulin(Hb)(-1)), and higher GPx activity (175.2 (126.6-288.3) versus 49.2 (39.5-59.2) mU x (gHb)(-1)) compared with controls. The antioxidant activities in lung cancer subjects were not associated with age, sex, smoking status, or tumour cell types. However, more advanced disease (stage IV compared with stage IIIB) was associated with lower SOD activity. Using multivariable analysis, the presence of lung cancer independently predicted SOD and GPx activities. In conclusion, nonsmall cell lung carcinoma in Chinese subjects is associated with alterations in systemic antioxidant activities, which may play an important role in carcinogenesis.

Adult↗

PubMed2006

A prospective study of respiratory ciliary structure and function after stem cell transplantation.

We prospectively investigated the morphological and ciliary function abnormalities in 19 consecutive Chinese patients undergoing hemopoietic stem cell transplantation (HSCT) and studied their relationship with pulmonary complications. The percentage of structural ciliary abnormalities preceding HSCT was comparable to normal controls, but increased up to 1-year post-HSCT. However, the abnormalities did not correlate with ciliary or pulmonary function. Ciliary beat frequency (CBF) for patients undergoing autologous and allogeneic SCT was lower than that of matched controls, with a further decline at one year. There was, however, no significant change in pulmonary function for the whole cohort. There was considerable variation in CBF and ciliary abnormalities in all cases during 3-month interval assessments. Regular ciliary assessment did not predict the only two patients who eventually suffered from bronchiolitis obliterans (BO). We conclude that structural and functional ciliary abnormalities are common in recipients of HSCT, and predict post-HSCT deterioration. However, there is no evidence to show that CBF monitoring may be of prospective benefit.

Adult↗

PubMed2006

Recurrent pneumothorax in pregnancy: what should we do after placing an intercostal drain.

Recurrent pneumothorax is rare during pregnancy. We describe a Chinese woman, with a history of spontaneous pneumothorax managed with an intercostal drain, who developed a recurrent pneumothorax during her 32nd week of pregnancy. There is no consensus on management in this situation. We review the literature and discuss different management approaches. Thirty-six cases of antepartum pneumothorax have been reported in 31 case reports. An intercostal drain only (n=11) or surgeries (thoracotomy, n=9; or video-assisted thoracoscopy, n=2) were common treatment options with no surgical complications reported. Twenty-two (61%) patients progressed to a normal vaginal delivery, while the rest required forceps delivery (22%) or Caesarean section (14%). No single treatment option outweighed the others. There were no maternal or foetal complications reported in those who underwent antepartum surgical intervention. Surgical management of recurrent pneumothorax during pregnancy is well tolerated.

Adult↗

PubMed2005

An analytical study on the thermal effects of cryosurgery on selective cell destruction.

The aim of cryosurgery is to kill cells within a closely defined region maintained at a predetermined low temperature. To effectively kill cells, it is important to be able to predict and control the cooling rate over some critical range of temperatures and freezing states in order to regulate the spatial extent of injury during any freeze-thaw protocol. The objective of manipulating the freezing parameters is to maximize the destruction of cancer cells within a defined spatial domain while minimizing cryoinjury to the surrounding healthy tissue. An analytical model has been developed to study the rate of cell destruction within a liver tumor undergoing a freeze-thaw cryosurgical process. Temperature transients in the tumor undergoing cryosurgery have been quantitatively investigated. The simulation is based on solving the transient bioheat equation using the finite volume scheme for a single or multiple-probe geometry. Simulated results show good agreement with experimental data obtained from in vivo clinical study. The calibrated model has been employed to study the effects of different freezing rates, freeze-thaw cycle(s), and multi-probe freezing on cell damage in a liver tumor. The effectiveness of each treatment protocol is estimated by generating the cell survival-volume signature and comparing the percentage of cell damaged within the ice-ball. Results from the model show that employing freeze-thaw cycles has the potential to enhance cell destruction within the cancerous tissue. Results from this study provide the basis for designing an optimized cryosurgical protocol which incorporates thermal effects and the extent of cell destruction within tumors.

Biophysical Phenomena↗

PubMed2005

A diffusion model for drying of a heat sensitive solid under multiple heat input modes.

To obtain optimal drying kinetics as well as quality of the dried product in a batch dryer, the energy required may be supplied by combining different modes of heat transfer. In this work, using potato slice as a model heat sensitive drying object, experimental studies were conducted using a batch heat pump dryer designed to permit simultaneous application of conduction and radiation heat. Four heat input schemes were compared: pure convection, radiation-coupled convection, conduction-coupled convection and radiation-conduction-coupled convection. A two-dimensional drying model was developed assuming the drying rate to be controlled by liquid water diffusion. Both drying rates and temperatures within the slab during drying under all these four heat input schemes showed good accord with measurements. Radiation-coupled convection is the recommended heat transfer scheme from the viewpoint of high drying rate and low energy consumption.

Convection↗

PubMed2005

Design of high affinity cyclic pentapeptide ligands for kappa-opioid receptors.

Using results from our previously reported cyclic opioid peptide series and reliable models for mu-, delta-, and kappa-opioid receptors (MOR, DOR, and KOR, respectively) and their complexes with peptide ligands, we have designed and synthesized a series of cyclic pentapeptides of structure Tyr-C[D-Cys-Phe-Phe-X]-NH2, cyclized via disulfide, methylene, or ethylene dithioethers, and where X = D- or L-Cys; or D- or L-penicillamine (Pen; beta,beta-dimethylcysteine). Determination of binding affinities to MOR, DOR, and KOR revealed that members of this series with X = D- or L-Cys display KOR affinities in the low nanomolar range, demonstrating that a 'DPDPE-like' tetrapeptide scaffold is suitable not only for DOR and MOR ligands, but also for KOR ligands. The cyclic pentapeptides reported here are not, however, selective for KOR, rather they display significant selectivity and high affinity for MOR. Indeed, peptide 8, Tyr-C[D-Cys-Phe-Phe-Cys]-NH2-cyclized via a methylene dithioether, shows picomolar binding affinity for MOR ( = 16 pm) with more than 100-fold selectivity for MOR vs. DOR or KOR, and may be of interest as a high affinity, high selectivity MOR ligand. Nonetheless, the high affinity KOR peptides in this series represent excellent leads for the development of structurally related, selective KOR ligands designed to exploit structurally specific features of KOR, MOR, and DOR.

Affinity Labels↗

PubMed2005

Inhaled fluticasone in bronchiectasis: a 12 month study.

BACKGROUND: The clinical efficacy of inhaled corticosteroid (ICS) treatment has not been evaluated in bronchiectasis, despite the presence of chronic airway inflammation. METHODS: After three consecutive weekly visits, 86 patients were randomised to receive either fluticasone 500 mug twice daily (n = 43, 23F, mean (SD) age 57.7 (14.4) years) or matched placebo (n = 43, 34F, 59.2 (14.2) years) and reviewed regularly for 52 weeks in a double blind fashion. RESULTS: 35 and 38 patients in the fluticasone and placebo groups completed the study. Significantly more patients on ICS than on placebo showed improvement in 24 hour sputum volume (OR 2.5, 95% CI 1.1 to 6.0, p = 0.03) but not in exacerbation frequency, forced expiratory volume in 1 second, forced vital capacity, or sputum purulence score. Significantly more patients with Pseudomonas aeruginosa infection receiving fluticasone showed improvement in 24 hour sputum volume (OR 13.5, 95% CI 1.8 to 100.2, p = 0.03) and exacerbation frequency (OR 13.3, 95% CI 1.8 to 100.2, p = 0.01) than those given placebo. Logistic regression models revealed a significantly better response in sputum volume with fluticasone treatment than with placebo among subgroups of patients with 24 hour sputum volume <30 ml (p = 0.04), exacerbation frequency </=2/year (p = 0.04), and sputum purulence score >5 (p = 0.03). CONCLUSIONS: ICS treatment is beneficial to patients with bronchiectasis, particularly those with P. aerurginosa infection.

Administration, Inhalation↗

PubMed2005

A prediction rule for clinical diagnosis of severe acute respiratory syndrome.

A prospective study was undertaken to identify clinical, radiographical, haematological and biochemical profiles of severe acute respiratory syndrome (SARS) patients. A prediction rule, which demarcates low from high risk patients for SARS in an outbreak situation was developed. A total of 295 patients with unexplained respiratory illnesses, admitted to Queen Mary Hospital, Hong Kong SAR, China, in March to July 2003, were evaluated for clinical, radiological, haematological and alanine transaminase (ALT) data daily for 3 days after hospitalisation. In total, 44 cases were subsequently confirmed to have SARS by RT-PCR (68.2%) and serology (100%). The scoring system of attributing 11, 10, 3, 3 and 3 points to the presence of independent risk factors, namely: epidemiological link, radiographical deterioration, myalgia, lymphopenia and elevated ALT respectively, generated high and low-risk (total score 11-30 and 0-10, respectively) groups for SARS. The sensitivity and specificity of this prediction rule in positively identifying a SARS patient were 97.7 and 81.3%, respectively. The positive and negative predictive values were 47.8 and 99.5%, respectively. The prediction rule appears to be helpful in assessing suspected patients with severe acute respiratory syndrome at the bedside, and should be further validated in other severe acute respiratory syndrome cohorts.

Adult↗

PubMed2005

Beta-lactoglobulin is a thermal marker in processed milk as studied by electrophoresis and circular dichroic spectra.

As much of the sterilization process involves heat treatment during the preparation of milk on an industrial scale, the unpredictable measures of the process are an essential issue in determining the quality of the milk. The purpose of the present study was to investigate the major protein change(s) of whey proteins in processed milk and extend the knowledge for future reference in the dairy industry. Using a native polyacrylamide gel electrophoresis, we showed almost a 90% loss and denaturation of beta-lactoglobulin (LG), but not alpha-lactalbumin (LA), in some brands of the processed and dry milks. Immunochemical analysis using Western blotting revealed that part of the loss was attributed to the formation of large multiple forms of LG in the processed product. Such denaturation was presumably associated with the heating procedure used in the process. Essentially, LG was the only major fraction converted to aggregates in milk heated at 95 degrees C for 30 min on 2-dimensional PAGE. The detailed thermal denaturation of purified LG and LA at various temperatures (50 to 95 degrees C) and time (5 to 960 s) were investigated using a circular dichroic analysis. The maximal changes of ellipticity at 205 nm (converting beta-structure to disordered structure) were correlated to heating temperature and time. There were no significant conformational changes of LG at temperatures below 70 degrees C for as long as 480 s. Pronounced and rapid changes occurred between 80 to 95 degrees C in a time-dependent manner. Fifty percent of the maximal changes could be reached within 15 s. In conclusion, the unique chemical and immunochemical loss and conformational changes made LG a superior marker for evaluating the thermal processing of milk. The detailed thermal denaturation curves of LG constructed with its time and temperature in this study provide a valuable reference for the dairy industry. We postulate that heat treatment over 80 degrees C in 15 s may induce a significant denaturation of milk LG.

Amino Acid Sequence↗

PubMed2004

Lymphoepithelioma-like carcinoma of the lung: experience with ten cases.

OBJECTIVE: Lymphoepithelioma-like carcinoma of the lung (LELC) is a rare form of non-small cell lung cancer predominantly affecting young non-smoking Asians, and there has been only limited experience in its palliative chemotherapy and radiotherapy. We investigated tumour response, time to progression and survival of LELC patients who received such treatment. DESIGN: We prospectively recruited patients with confirmed advanced LELC who were treated with chemoradiotherapy in our unit, a regional tertiary referral centre for lung cancer treatment. RESULTS: There were 10 patients (five males, age 47 +/- 9.8 years, median follow-up 22 months) with advanced LELC (respectively 1, 4, and 5 patients at TNM stage IIIA, IIIB and IV) who received systemic chemotherapy and radiotherapy. The primary chemotherapy regimen consisted of 5-fluorouracil/leucovorin/cisplatin. The response rates to 5-fluorouracil/leucovorin/cisplatin were 60% partial response, 10% stable disease, and 30% progressive disease. Eight patients were also given local radiotherapy. Five patients received salvage chemotherapy when disease progressed after primary chemotherapy. The overall median survival was 23.4 +/- 4.7 months. CONCLUSION: The encouraging response to combination chemotherapy with 5-fluorouracil/leucovorin/ cisplatin, although empirical, supports its use with radiotherapy in unresectable lymphoepithelioma-like carcinoma of the lung.

Adult↗

PubMed2004

Pentaglobin in steroid-resistant severe acute respiratory syndrome.

SETTING: The treatment of severe acute respiratory syndrome (SARS) is at best controversial, although there is considerable anecdotal experience to show the benefits of corticosteroid therapy for selected patients. Some patients deteriorate relentlessly despite treatment with antibiotic, corticosteroid and mechanical ventilation. OBJECTIVE: To attempt to determine the clinical efficacy of pentaglobin, an IgM-enriched immunoglobulin preparation, on 12 severe SARS patients who continued to deteriorate despite corticosteroid and ribavirin therapy. DESIGN: Retrospective analysis of daily quantitative and radiographic data on the cohort in a regional teaching hospital. RESULTS AND CONCLUSION: There was significant improvement in radiographic scores, when compared with day 1, on days 5, 6 and 7 (P < 0.05) after commencement of pentaglobin treatment. Similarly, there was significant improvement in oxygen requirement, when compared with day 1, on days 6 and 7 (P < 0.05) after commencement of pentaglobin treatment. There were no reported adverse events attributable to pentaglobin administration. Ten patients made an uneventful recovery after treatment. One elderly man died from cardiorespiratory arrest despite clinical and radiological improvement, and another patient is making good progress. Pentaglobin is safe and probably effective in the treatment of steroid-resistant SARS. A double-blind placebo-controlled study should therefore be considered.

Adrenal Cortex Hormones↗

PubMed2003

Coriolus versicolor polysaccharide peptide slows progression of advanced non-small cell lung cancer.

BACKGROUND: Non-small cell lung cancer (NSCLC) is a leading cause of cancer deaths, and over 60% of patients present with advanced stages. Although polysaccharide peptides (PSP), isolated from the fungus Coriolus versicolor, have been reported to have anti-tumor effects, its clinical efficacy has not been properly evaluated. METHODS: Double-blind placebo-controlled randomized study to evaluate the effects of 28-day administration of PSP (Windsor Pharmaceutical, Hong Kong) on patients, who had completed conventional treatment for advanced NSCLC. RESULTS: Thirty-four patients, with no significant difference in their baseline demographic, clinical or tumor characteristics, or previous treatment regimes (P>0.05) were recruited into each of the PSP and control arms. After 28-day treatment, there was a significant improvement in blood leukocyte and neutrophil counts, serum IgG and IgM, and percent of body fat among the PSP, but not the control, patients (P<0.05). Although the evaluable PSP patients did not improve in NSCLC-related symptoms, there were significantly less PSP patients withdrawn due to disease progression, than their control counterparts (5.9 and 23.5%, respectively; P=0.04; OR 4.00). There was no reported adverse reaction attributable to the trial medications. CONCLUSION: PSP treatment appears to be associated with slower deterioration in patients with advanced NSCLC.

Adult↗

PubMed2003

Effects of erythromycin on Pseudomonas aeruginosa adherence to collagen and morphology in vitro.

The airways of patients with bronchiectasis and cystic fibrosis are often chronically colonised by Pseudomonas aeruginosa (PA), which is virtually impossible to eradicate. Low-dose erythromycin (EM), for unknown mechanisms, is efficacious in bronchiectasis and diffuse panbronchiolitis. In this study, an in vitro model to investigate PA adherence to human type IV basement collagen was developed by using scanning electron microscopy (SEM). There were significantly less PA bacilli per 20 random SEM fields (4,000x) when PA was cultured in 0.05, 0.5 and 5 microg x mL(-1) of EM compared with control (absence of EM). Adherence density (20 SEM fields x log(-1) inocular size) for PA obtained from no EM (56.8 +/- 43.16) was significantly higher than that obtained from 0.05, 0.5, and 5 microg x mL(-1) EM (21.5 +/- 17.56, 23.3 +/- 16.65, and 21.4 +/- 12.65 respectively). By using SEM it was found that PA, when incubated in EM (0.05, 0.5, 5 microg x mL(-1)) had a significant reduction in its diagonal length, radius, height, volume and surface area. It is possible, therefore, that these misshaped Pseudomonas aeruginosa bacilli are more susceptible to host defence mechanisms, while at the same time less adherent to the basement membrane of the airway in vivo. Therefore, this could help explain the clinical efficacy of low-dose erythromycin therapy on patients with Pseudomonas aeoruginosa infection.

Bacterial Adhesion↗

PubMed2003

Lymphoepithelioma-like carcinoma of the lung in a patient with silicosis.

Silicosis is an important form of pneumoconiosis, which is caused by significant exposure to crystalline silica. The carcinogenicity of silica, despite traditional beliefs, in relation to lung cancer has been controversial. Lymphoepithelioma-like carcinoma of the lung, an Epstein-Barr virus-associated undifferentiated carcinoma, is a rare entity of pulmonary malignancy, which tends to affect young nonsmoking Asians. The first case of silicosis, initially complicated by pulmonary tuberculosis, which later developed into advanced lymphoepithelioma-like carcinoma of the lung is reported. A combination of 5-fluorouracil, cisplatin and calcium folinate resulted in partial tumour response.

Aged↗

PubMed2001

SUMO modification of Rad22, the Schizosaccharomyces pombe homologue of the recombination protein Rad52.

The Schizosaccharomyces pombe rad31 and hus5 genes are required for the DNA damage response, as mutants defective in these genes are sensitive to DNA damaging agents, such as UV and ionising radiation and to the DNA synthesis inhibitor hydroxyurea (HU). Sequence analysis has suggested that rad31 and hus5 encode components of the Pmt3 (SUMO) modification process in S.pombe. We show here that the rad31 null and hus5.62 mutants display reduced levels of Pmt3 modification. We have initiated a search for proteins required for the DNA damage response, which may be modified by Pmt3 and have identified Rad22, the fission yeast homologue of the recombination protein Rad52. Purification of myc + His-tagged Rad22 protein from cells expressing HA-tagged Pmt3 identifies an 83 kDa species which cross-reacts with anti-HA antisera. We show here that Rad22 interacts with Rhp51 and Rpa70 (the fission yeast homologues of Rad51 and the large subunit of RPA, respectively), but that neither of these proteins appears to be responsible for the 83 kDa species. The 83 kDa species is observed when extracts are prepared under both native and denaturing conditions, and is also observed when myc + His-tagged Rad22 and Pmt3 are expressed at wild type levels, suggesting that Rad22 is modified by Pmt3 in vivo. We have established an S.pombe in vitro Pmt3 modification system and have shown that Rad22 and Rhp51 are modified in vitro, but that Rpa70 is not.

DNA Damage↗

PubMed2001

Pulmonary sequelae of treatment for breast cancer: a prospective study.

PURPOSE: To prospectively study the effects of loco-regional radiotherapy in women with breast cancer. METHODS AND MATERIALS: Thirty consecutive patients with breast resection underwent clinical, lung function, radiographic, and thoracic high-resolution computed tomography evaluation before and at 1, 3, 6, and 12 months after adjuvant radiotherapy. Chemotherapy was also administered to 15 patients. RESULTS: Nineteen patients reported mild respiratory symptoms at 1 month, which resolved completely at 6 months after radiotherapy. Opacities were present on 80% of chest radiographs and in all patients on high-resolution computed tomography by 3 months. These opacities became compact and persisted on high-resolution computed tomography at 12 months. Lung function indices, including FEV1, FVC, TLC, and DLCO, progressively declined after radiotherapy, and was irreversible at 12 months (p < 0.05). Patients who received chemotherapy did not have significantly different lung function indices compared with their counterparts at all time points (p > 0.05). CONCLUSIONS: Our results have shown that adjuvant loco-regional radiotherapy, a common practice in breast cancer treatment, is associated with irreversible reduction in lung function parameters. These changes are accompanied by radiological evidence of persistent lung injury. Further studies should be performed to evaluate the incidence and long-term pulmonary sequelae of current treatment for breast cancer.

Adult↗

PubMed2001

Suppression of cell cycle progression by a fungal lectin: activation of cyclin-dependent kinase inhibitors.

The antiproliferative activity of a fungal lectin (VVL) isolated from the mushroom, Volvariella volvacea, was studied using a battery of cultured tumor cell lines. It was revealed that [(3)H]thymidine incorporation into the cell lines was markedly reduced at 0.32 microM VVL. When S180 mouse sarcoma cells were incubated for 48 hr with doses of VVL ranging from 0.32 to 0.8 microM, prominent blebs on the cell surface and large vacuoles in the cytoplasm, but not apoptotic bodies, were observed under a fluorescence microscopy. VVL did not exert ribosome-inactivating activity or induce any changes in the expression of cyclins A, D1, and E. However, it did activate the expression of cyclin kinase inhibitors, namely p21, p27, p53, and Rb, in a dose-dependent manner. Flow cytometric analysis demonstrated an accumulation of cells in the G2/M phase in a time- and dose-dependent manner, indicating that VVL arrested cell proliferation by blocking cell cycle progression in the G2/M phase.

Agaricales↗

PubMed2001

Fullerene lipids: synthesis of novel nitrogen-bridged.

Reactions of methyl 6-azido-hexanoate, 8-azidooctanoate, and 12-azido-dodecanoate with [60]fullerene (1) gave the corresponding aza-[60]fullerene ester derivatives (2a-2c, 22-35% based on the amount of [60]fullerene reacted). The nitrogen atom is bonded to the [60]fullerene cage to yield a "[5,6]-open" type aza substructure. This was confirmed by the appearance of 30-31 sp2 signals at deltac 133-147 in the carbon nuclear magnetic resonance spectra. Reaction of methyl 11-azido-7-undecynoate with [60]fullerene furnished a mixture of aza-[60]fullerene (2d, 53%) and aziridine-[60]fullerene (2e, 38%) ester derivatives. Compound 2e was identified as the "[6,6]-closed" type aziridine-[60]fullerene derivative, which displayed 10 sp2 signals in the region deltac 140-145 and one signal at deltac 85.05 for the sp3 carbons of the cage. Refluxing a solution of compound 2d in toluene for 50 h gave about 50% yield of compound 2e, but not vice versa.

Aziridines↗