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Biomedical subjects

K K Ho

Publications and source records attributed to K K Ho.

At least 37 records · Page 2Linked to original sources
PubMed2001

Economic assessment of rheolytic thrombectomy versus intracoronary urokinase for treatment of extensive intracoronary thrombus: Results from a randomized clinical trial.

BACKGROUND: Despite advances in mechanical and pharmacologic therapy, thrombus-containing lesions are at high risk for adverse events and remain a challenging subset for percutaneous coronary revascularization. Recently, rheolytic thrombectomy with the AngioJet device has been shown to safely remove intracoronary thrombus, but the overall cost-effectiveness of this technique is unknown. METHODS: We determined in-hospital and 1-year follow-up costs for 349 patients with overt intracoronary thrombus who were randomly assigned to treatment with intracoronary urokinase (6- to 30-hour infusion followed by definitive revascularization; n = 169) or immediate thrombectomy with the AngioJet device (n = 180) as part of the Vein Graft AngioJet Study (VeGAS) 2 trial. Catheterization laboratory costs were based on measured resource utilization and 1998 unit costs, whereas all other costs were estimated from hospital charges and cost center-specific cost-to-charge ratios. RESULTS: Compared with urokinase, rheolytic thrombectomy reduced the incidence of periprocedural myocardial infarction (12.8% vs 30.3%, P <.001) and major hemorrhagic complications (2.8% vs 11.2%, P <.001) and shortened length of stay by nearly 1 day (4.2 vs 4.9 days; P =.02). As a result, AngioJet treatment reduced procedural costs, hospital room/nursing costs, and ancillary costs with resulting hospital cost savings of approximately $3500 per patient during the initial hospitalization ($15,311 vs $18,841, P <.001). These cost savings were maintained at 1 year of follow-up ($24,389 vs $29,109, P <.001). CONCLUSIONS: Compared with standard treatment with intracoronary urokinase, rheolytic thrombectomy both improves clinical outcomes and reduces overall medical care costs for patients with extensive intracoronary thrombus.

Angioplasty, Balloon, Coronary↗
PubMed2001

Oral estrogen antagonizes the metabolic actions of growth hormone in growth hormone-deficient women.

We have determined whether oral estrogen reduces the biological effects of growth hormone (GH) in GH-deficient (GHD) women compared with transdermal estrogen treatment. In two separate studies, eight GHD women randomly received either oral or transdermal estrogen for 8 wk before crossing over to the alternate route of administration. The first study assessed the effects of incremental doses of GH (0.5, 1.0, 2.0 IU/day for 1 wk each) on insulin-like growth factor I (IGF-I) levels during each estrogen treatment phase. The second study assessed the effects of GH (2 IU/day) on lipid oxidation and on protein metabolism using the whole body leucine turnover technique. Mean IGF-I level was significantly lower during oral estrogen treatment (P < 0.05) and rose dose dependently during GH administration by a lesser magnitude (P < 0.05) compared with transdermal treatment. Postprandial lipid oxidation was significantly lower with oral estrogen treatment, both before (P < 0.05) and during (P < 0.05) GH administration, compared with transdermal treatment. Protein synthesis was lower during oral estrogen both before and during GH administration (P < 0.05). Oral estrogen antagonizes several of the metabolic actions of GH. It may aggravate body composition abnormalities already present in GHD women and attenuate the beneficial effects of GH therapy. Estrogen replacement in GHD women should be administered by a nonoral route.

Administration, Cutaneous↗
PubMed2001

Binding and functional studies with the growth hormone receptor antagonist, B2036-PEG (pegvisomant), reveal effects of pegylation and evidence that it binds to a receptor dimer.

GH actions are dependent on receptor dimerization. The GH receptor antagonist, B2036-PEG, has been developed for treating acromegaly. B2036 has mutations in site 1 to enhance receptor binding and in site 2 to block receptor dimerization. Pegylation (B2036-PEG) increases half-life and lowers immunogenicity, but high concentrations are required to control insulin-like growth factor-I levels. We examined antagonist structure and function and the impact of pegylation on biological efficacy. Unpegylated B2036 had a 4.5-fold greater affinity for GH binding protein (GHBP) than GH but similar affinity for membrane receptor. Pegylation substantially reduced membrane binding affinity and receptor antagonism, as assessed by a transcription assay, by 39- and 20-fold, respectively. GHBP reduced antagonist activity of unpegylated B2036 but did not effect antagonism by B2036-PEG. B2036 down-regulated receptors, and membrane binding sites doubled in the presence of dimerization-blocking antibodies, suggesting that B2036 binds to a receptor dimer. It is concluded that the high concentration requirement of B2036-PEG for clinical efficacy relates to pegylation, which decreases binding to membrane receptor but has the advantages of reduced clearance, immunogenicity, and interactions with GHBP. Our studies suggest that B2036 binds to a receptor dimer and induces internalization but not signaling.

Carrier Proteins↗
PubMed2001

Epidemiology and detection of human immunodeficiency virus among pregnant women in Hong Kong.

OBJECTIVES: To determine the epidemiology of human immunodeficiency virus infection among pregnant women and the neonatal outcomes in Hong Kong. DESIGN: Retrospective observational study composed of two parts: record review of pregnant women and unlinked anonymous screening of cord blood from neonates. SETTING: Two human immunodeficiency virus clinics and the Government Virus Unit. PARTICIPANTS: Female patients attending the two clinics who became pregnant and neonates who underwent routine metabolic screening by the Government Virus Unit between 1992 and 1999. MAIN OUTCOME MEASURES: The outcomes of neonates born to women who had human immunodeficiency virus infection during pregnancy. RESULTS: Forty-one human immunodeficiency virus-related pregnancies were recorded among 32 infected women. Fifteen pregnancies were terminated, of which 14 were in women who knew their infection status before conception. Twenty-six pregnancies continued to term, resulting in 26 live births. Twelve babies were born to women who knew their infection status before delivery. One baby was confirmed to be infected. Six women were given zidovudine for prophylaxis against vertical transmission and none of the babies were infected at birth. Of the remaining 14 human immunodeficiency virus-related pregnancies, the mothers' status became known only at a later date and nine (64.3%) babies were confirmed to be infected at the age of 18 months or older. The rate ratio of giving birth to an infected baby was 8.18 from mothers who did not know their status antenatally. Unlinked anonymous screening showed that the seroprevalence rate for human immunodeficiency virus in pregnant women was 0.032% (1/3125) in Hong Kong in 1999. CONCLUSIONS: Human immunodeficiency virus-related pregnancy is not rare in Hong Kong and the majority of infected mothers were not identified and treated. Detection of these pregnancies will be invaluable for the prevention of mother-to-child transmission. Universal antenatal screening of human immunodeficiency virus antibody is proposed as an effective strategy.

AIDS Serodiagnosis↗
PubMed2000

Deaths of children during an outbreak of hand, foot, and mouth disease in sarawak, malaysia: clinical and pathological characteristics of the disease. For the Outbreak Study Group.

From April through June 1997, 29 previously healthy children aged <6 years (median, 1.5 years) in Sarawak, Malaysia, died of rapidly progressive cardiorespiratory failure during an outbreak of hand, foot, and mouth disease caused primarily by enterovirus 71 (EV71). The case children were hospitalized after a short illness (median duration, 2 days) that usually included fever (in 100% of case children), oral ulcers (66%), and extremity rashes (62%). The illness rapidly progressed to include seizures (28%), flaccid limb weakness (17%), or cardiopulmonary symptoms (of 24 children, 17 had chest radiographs showing pulmonary edema, and 24 had echocardiograms showing left ventricular dysfunction), resulting in cardiopulmonary arrest soon after hospitalization (median time, 9 h). Cardiac tissue from 10 patients showed normal myocardium, but central nervous system tissue from 5 patients showed inflammatory changes. Brain-stem specimens from 2 patients were available, and both specimens showed extensive neuronal degeneration, inflammation, and necrosis, suggesting that a central nervous system infection was responsible for the disease, with the cardiopulmonary dysfunction being neurogenic in origin. EV71 and possibly an adenovirus, other enteroviruses, or unknown cofactors are likely responsible for this rapidly fatal disease.

Antigens, Viral↗
PubMed2000

Impact of smoking on health-related quality of life after percutaneous coronary revascularization.

BACKGROUND: PTCA is performed primarily to improve health-related quality of life (HRQOL) in patients with symptomatic coronary artery disease. In patients undergoing PTCA, smoking has been shown to increase risks of late myocardial infarction and death. Whether smoking also affects HRQOL after PTCA is currently unknown. METHODS AND RESULTS: We examined the relation between smoking status and HRQOL among 1432 patients who underwent PTCA as part of 2 multicenter clinical trials. HRQOL was assessed with the use of the Medical Outcomes Study SF-36 questionnaire. Patients were classified as smokers (n=301), quitters (n=141), or nonsmokers (n=990) on the basis of their smoking status at the time of their index procedure and during the first year of follow-up. For the overall population, HRQOL improved significantly after PTCA for all scales except general health perception, with improvements ranging from 5.5 points for mental health to 23.2 points for role-physical functioning. After adjustment for baseline characteristics and initial HRQOL, nonsmokers had gains at 6 months that were larger than those of smokers for all health domains: physical function (15.4 versus 10.4 points), role-physical (24.5 versus 13.9), pain (18.4 versus 13.3), general health perception (1.7 versus -4.5), vitality (11.0 versus 4. 7), social function (12.8 versus 3.5), role-emotional (13.5 versus 6. 7), and mental health (6.8 versus 0.8; P:<0.02 for all comparisons). Quitters had 6-month HRQOL improvements that were greater than those in smokers for all domains as well. Findings were similar at 1 year. CONCLUSIONS: Quality-of-life benefits of PTCA are diminished by continued smoking. Efforts to promote smoking cessation at the time of PTCA may substantially improve the health outcomes of these procedures.

Age Factors↗
PubMed2000

Impact of end-stage renal disease on clinical and angiographic outcomes after coronary stenting.

Although patients with end-stage renal disease (ESRD) are at high risk for restenosis that requires repeat revascularization after balloon angioplasty, their restenosis rate after coronary stenting is still unknown. Over a 4-year period, we performed coronary stenting on 40 lesions in 34 patients with ESRD. We compared these lesions with 80 lesions from patients without renal disease who underwent coronary stenting in the STARS and WINS clinical trials, matched for treatment site, diabetes, lesion length, and reference vessel diameter. Quantitative coronary angiography was performed on all lesions and clinical outcomes were assessed at 9-month follow-up. Clinical and angiographic characteristics were well matched between the 2 groups and acute clinical success rates were similar. Despite comparable initial angiographic results over the 9-month follow-up period, repeat target lesion revascularization was twice as frequent in the ESRD group compared with the control group (35% vs 16%, p <0.05). After adjusting for differences in postprocedural minimum lumen diameter and other angiographic and clinical characteristics, ESRD remained the most important predictor of late target lesion revascularization (relative risk = 2.3, p = 0.04). In addition, overall 9-month mortality was higher for ESRD patients than for the control population (18% vs 2%, p <0.01). Thus, despite similar angiographic results, patients with ESRD are at higher risk for target lesion revascularization after coronary stenting than controls. Nonetheless, most patients with ESRD do not develop restenosis after stent placement, suggesting an important role for stenting in the management of this challenging population.

Aged↗
PubMed2000

Holter monitoring: are two days better than one?

The optimal duration of Holter monitoring (HM) to minimize costs and maximize yield is unknown. In a retrospective review of 164 patients referred to a tertiary care center for evaluation with 2 days of HM, we found that 48 hours was not cost effective when compared with the traditional 24-hour period.

Arrhythmias, Cardiac↗
PubMed2000

Percutaneous coronary revascularization in elderly patients: impact on functional status and quality of life.

BACKGROUND: Percutaneous coronary intervention (PCI) is frequently performed in elderly patients, but little is known about its impact on overall health and quality of life. OBJECTIVE: To examine changes in health-related quality of life among elderly patients after PCI. DESIGN: Observational study. SETTING: 75 U.S. hospitals. PATIENTS: Participants in two clinical trials of PCI. MEASUREMENTS: Health-related quality of life was assessed by using the Medical Outcomes Study Short Form (SF-36) survey and the Seattle Angina Questionnaire at baseline, 6 months, and 1 year. RESULTS: Serial data on health-related quality of life were available for 295 elderly (> or =70 years) and 1150 nonelderly (<70 years) patients. At 6 months, physical health had improved in 51% of elderly patients and mental health had improved in 29%. Cardiovascular-specific health status had improved in 58% to 75% of elderly patients. Improvement did not significantly differ between elderly and non-elderly patients at 6 months or 1 year. CONCLUSIONS: Elderly patients selected for participation in a trial of PCI had substantial improvements in health-related quality of life after PCI that were similar to those in younger patients.

Activities of Daily Living↗
PubMed2000

Suture-mediated closure of the femoral access site after cardiac catheterization: results of the suture to ambulate aNd discharge (STAND I and STAND II) trials.

Despite advances in other aspects of cardiac catheterization, manual or mechanical compression followed by 4 to 8 hours of bed rest remains the mainstay of postprocedural femoral access site management. Suture-mediated closure may prove to be an effective alternative, offering earlier sheath removal and ambulation, and potentially a reduction in hemorrhagic complications. The Suture To Ambulate aNd Discharge trial (STAND I) evaluated the 6Fr Techstar device in 200 patients undergoing diagnostic procedures, with successful hemostasis achieved in 99% of patients (94% with suture closure only) in a median of 13 minutes, and 1% major complications. STAND II randomized 515 patients undergoing diagnostic or interventional procedures to use of the 8Fr or 10Fr Prostar-Plus device versus traditional compression. Successful suture-mediated hemostasis was achieved in 97.6% of patients (91.2% by the device alone) compared with 98.9% of patients with compression (p = NS). Major complication rates were 2.4% and 1.1%, and met the Blackwelder's test for equivalency (p <0.05). Median time to hemostasis (19 vs 243 minutes, p <0.01) and time to ambulation (3.9 vs 14.8 hours, p <0.01) were significantly shorter for suture-mediated closure. Suture-mediated closure of the arterial puncture site thus affords reliable immediate hemostasis and shortens the time to ambulation without significantly increasing the risk of local complications.

Cardiac Catheterization↗
PubMed2000

Outcome of patients with acute myocardial infarction who are ineligible for primary angioplasty trials.

We determined acute outcome in 148 consecutive patients with ST segment elevation myocardial infarction undergoing angioplasty including 72 patients (48.7%) considered ineligible for primary angioplasty trials. Overall, in-hospital mortality for acute infarct angioplasty was 12%, with fivefold higher mortality in the trial-ineligible group (21% vs. 4%, P = 0.003). Thus, primary angioplasty trials continue to exclude nearly 50% of acute infarction patients and reported mortality rates of primary angioplasty trials are likely to be significantly lower than the unselected in-hospital mortality rates. Cathet. Cardiovasc. Intervent. 49:237-243, 2000.

Angioplasty, Balloon, Coronary↗
PubMed2000

Outcome of IgA nephropathy in adults graded by chronic histological lesions.

This prognostic study of primary immunoglobulin A (IgA) nephropathy focused on chronic irreversible glomerular sclerosis and interstitial fibrosis, based on the premise that this disease is characterized by a protracted and, for many, progressive course. We used a chronicity-based histological grading system to assess the biopsy specimens of 126 adults with IgA nephropathy over a median follow-up of 10 years. Our grading system included a glomerular grading (GG) of 1 to 3 based on the extent of glomerular sclerosis, a tubulointerstitial grading (TIG) of 1 to 3 based on the degree of tubular loss or interstitial fibrosis, and the evaluation of hyaline arteriolosclerosis (HA). These three histological parameters were correlated with each other and with serum creatinine level, degree of proteinuria, and blood pressure at the time of renal biopsy. Univariate analysis showed that these three histological and three clinical parameters were significantly correlated with renal survival. By multivariate analysis using the Cox regression model, GG, serum creatinine level, and degree of proteinuria represented independent prognostic factors of renal survival. For a subset of patients at a relatively early stage of disease with a serum creatinine level less than 130 micromol/L at the time of biopsy, all three histological features and degree of proteinuria were significantly correlated with renal survival, and GG was the only independent prognostic factor for renal outcome. This study shows that glomerular sclerosis represents the most important prognostic factor in adult patients with primary IgA nephropathy and has a strong predictive value. Our chronicity-based histological grading system not only correlates well with the natural history of IgA nephropathy but is also reproducible and relatively simple to apply.

Adolescent↗
PubMed2000

Incidence and predictors of myocardial infarction among patients with atrial fibrillation.

OBJECTIVES: We sought to evaluate the utility of excluding myocardial infarction (MI) in patients presenting to the emergency department (ED) with atrial fibrillation (AF) and to identify predictors of MI in this group. BACKGROUND: Patients with AF are frequently admitted to the hospital, in part, to exclude an associated MI. There are no prospective data on unselected patients to support this common practice. METHODS: We conducted a prospective cohort study of all patients who presented to a single-center ED with the primary diagnosis of AF. RESULTS: Of a total of 255 patients, 190 (75%) were admitted to the hospital, and 109 of them underwent a standard "rule-out MI" protocol. Of these 109 patients, six (5.5%) were identified as having an acute MI at the time of admission. Chest pain was present in 39% of patients, with a sensitivity and specificity for the occurrence of MI of 100% and 65%, respectively. ST segment elevation or depression was present in 43% of patients, with a sensitivity and specificity of 100% and 51%. The presence of either major ST segment depression (>2 mm) or elevation on the admission electrocardiogram (ECG) was present in 6%, with a sensitivity of 100% and a specificity of 99%. The resulting positive and negative predictive values were 86% (95% confidence interval [CI] 42% to 99%) and 100% (95% CI 96% to 100%), respectively. Use of this criterion would have reduced the number of rule-out MIs in our study group by 94%, with no loss of sensitivity. CONCLUSIONS: Chest pain and ST segment depression are extremely common findings in patients presenting to the ED with AF and have limited power to predict MI. In contrast, ECG evidence of ST segment elevation or depression >2 mm appears to be a reliable discriminator of which patients are at risk for MI. Patients without significant ST segment changes are at very low risk for MI and may not require performance of the rule-out MI protocol or hospital admission if clinically stable.

Aged↗
PubMed2000

Mycosis fungoides bullosa simulating pyoderma gangrenosum.

A patient with mycosis fungoides (MF) bullosa had a rapidly growing, painful necrotic mass on the left ankle which extended by peripheral bulla formation, clinically resembling pyoderma gangrenosum. Histopathology confirmed MF bullosa with both intraepidermal and subepidermal bulla formation.

Antineoplastic Agents, Phytogenic↗
PubMed2000

Pemphigus with pemphigoid-like presentation, associated with squamous cell carcinoma of the tongue.

A 53-year-old woman presented with an inoperable squamous cell carcinoma of the tongue associated with tense large bullae consistent with bullous pemphigoid, preceded by a prodrome of urticarial plaques. The histological findings showed a regenerating subepidermal blister with eosinophils and no acantholysis. Direct immunofluorescence study, however, showed positive staining for IgG and C3 throughout the epidermis consistent with pemphigus. The blistering eruption had no mucosal involvement and responded to low dose corticosteroids. Our patient may represent another presentation of a 'paraneoplastic pemphigus spectrum'.

Carcinoma, Squamous Cell↗
PubMed2000

Gender- and height-related limits of muscle strength in world weightlifting champions.

To assess factors that limit human muscle strength and growth, we examined the relationship between performance and body dimensions in the world weightlifting champions of 1993-1997. Weight lifted varied almost exactly with height squared (Ht(2.16)), suggesting that muscle mass scaled almost exactly with height cubed (Ht(3.16)) and that muscle cross-sectional area was closely correlated with body height, possibly because height and the numbers of muscle fibers in cross section are determined by a common factor during maturation. Further height limitations of muscle strength were shown by only one male champion >/=183 cm and no female champions >/=175 cm. The ratio of weight lifted to mean body cross-sectional area was approximately constant for body-weight classes </=83 kg for men and </=64 kg for women and decreased abruptly for higher weight classes. These findings suggest a nearly constant fraction of body mass devoted to muscle in lighter lifters and a lesser fraction in heavier lifters. Analysis also suggests that contractile tissue comprises approximately 30% less body mass in female champions.

Body Height↗
PubMed2000

Characterization of a low affinity binding protein for growth hormone in rat serum.

GH forms a high Mr complex in rat serum distinct from that with GH-binding protein (GHBP). The present study investigates the nature of this complex. When subjected to AcA44 filtration chromatography, 125I-labeled human GH (hGH) in rat serum eluted in four peaks. Peak 1 eluted at the void volume, whereas peaks 2, 3, and 4 corresponded to the GHBP complex, free hGH, and iodide, respectively. Stripping of GHBP in serum by immunoaffinity chromatography depleted peak 2 but did not affect peak 1. Peak 1 accounted for 11.4 +/- 1.2% of the total radioactivity (mean +/- SEM; n = 6) in stripped serum. Addition of unlabeled hGH (0.9-9 microM) demonstrated the binding of [125I]hGH to be specific, with Scatchard analysis revealing an affinity of 0.88 +/- 0.03 x 10(5) M(-1)(n = 3)and a capacity of 2.46 +/- 0.14 microM. Sepharose CL-6B filtration chromatography showed the complex to be 260 kDa in size. The distribution of GH binding to GHBP and this high Mr serum factor was investigated by incubating [125I]hGH in sera containing a low (5 nM) and a high (35 nM) concentration of GHBP over a range of physiological GH concentrations. In sera containing a low concentration of GHBP, the proportion of GH complexed in peak 1 increased with increasing GH concentrations. In sera with a high concentration of GHBP, GH was complexed mainly in peak 2. Studies with normal rat sera revealed that more GH was complexed in peak 1 in male than in female rats (3.4 +/- 0.4% and 1.4 +/- 0.1%, respectively; P < 0.006), in contrast to that of peak 2 (1.1 +/- 0.2% and 7.6 +/- 0.4%, respectively; P < 0.002). In summary, we provide strong evidence for the existence of a factor in rat serum that binds GH with low affinity and high capacity. It has a Mr of approximately 240 kDa, assuming a 1:1 binding stoichiometry, and is immunologically distinct from GHBP. This factor may provide supplementary capacity for GH binding when binding to GHBP is saturated.

Algorithms↗