Search PubMed⌕ Search

Biomedical subjects

K Y Ho

Publications and source records attributed to K Y Ho.

At least 73 records · Page 4Linked to original sources
PubMed1997

MR angiography of the iliac and upper femoral arteries using four different inflow techniques.

OBJECTIVE: The purpose of this study was to compare two inflow MR angiography pulse sequences obtained with and without systolic synchronization. We also compared these two MR angiography pulse sequences with conventional angiography. SUBJECTS AND METHODS: Thirty-one consecutive patients who were scheduled for conventional angiography because of symptomatic atherosclerotic occlusive disease of the iliac or femoral artery underwent MR angiography using four different MR angiography techniques. These techniques consisted of a multiple two-dimensional inversion prepulse gradient-recalled echo technique (turbo field-echo) obtained with and without systolic synchronization and a multiple two-dimensional gradient-recalled echo technique (fast field-echo) obtained with and without systolic synchronization. We then compared image quality and our ability to detect and grade degree and length of stenosis, using conventional angiography as the gold standard. RESULTS: The systolic-synchronized turbo field-echo sequence produced the best results both objectively and subjectively. Comparing systolic-synchronized turbo field-echo and fast field-echo techniques with conventional angiography regarding detection and grading degree of stenoses, we found no statistically significant differences. CONCLUSION: Systolic synchronization proved to be of significant importance for image quality. The systolic-synchronized turbo field-echo pulse sequence proved to be superior to the other three MR angiography techniques.

Aged↗
PubMed1997

Periodontal manifestations and treatment of Sturge-Weber syndrome--report of two cases.

Encephalotrigeminal angiomatosis (Sturge-Weber syndrome) is a rather uncommon congenital condition characterized by the combination of venous angioma of the leptomeninges over the cerebral cortex with ipsilateral angiomatous lesions of the face and sometimes, the skull, jaws and oral soft tissues. Two patients came to the Kaohsiung Medical College Hospital's dental clinic with complaints of localized gingival enlargement or tumor-like swelling. Based on the presence of facial nevus flammeus, examinations of angiography, radiological evidence of calcific densities, and ipsilaterally intraoral vascular hyperplasia in the lip, cheek and gingiva, encephalotrigeminal angiomatosis was diagnosed. Dental management included plaque control instructions, scaling, root planing and periodontal surgery. Recurrence of gingival enlargement in both cases was noted, so periodontal surgery was performed a second time. Close follow up and complete plaque control have kept the periodontal condition fairly well under control in these two cases. We introduce the oral manifestations and the experience of treatments in these two cases.

Adolescent↗
PubMed1997

Collagen synthesis in idiopathic and dilantin-induced gingival fibromatosis.

Gingival fibromatosis is an uncommon but benign oral disease which causes progressive and non-hemorrhagic enlargement of the gingiva. There are two types of gingival fibromatosis: idiopathic gingival fibromatosis (GF), which is of unknown cause and may be associated with hereditary factors, and drug-induced gingival fibromatosis which is caused primarily by phenytoin intake. In cases of gingival fibromatosis, either the teeth are delayed in emergence or most of the crowns are embedded in the soft tissue even after full eruption. The objective of this study was to examine the basis of excess collagen formation in the two types of gingival fibromatosis in four patients admitted to the dental clinic at Kaohsiung Medical College Hospital, Kaohsiung, Taiwan. There were two male patients, aged ten (Case 1) and sixteen (Case 2), with idiopathic gingival fibromatosis and hypertrichosis, and two female patients, aged sixteen (Case 3) and eleven (Case 4), with Dilantin-induced gingival hyperplasia (DGH). Cultures of gingival fibroblast were established either from clinically excised hyperplastic tissues or from pre-orthodontic surgical normal gingiva. The synthesis of collagen and levels of prolyl hydroxylase, a key enzyme in collagen synthesis, were examined in the healthy and affected fibroblasts. Our studies showed that after two days in culture, fibroblasts from all four patients multiplied faster than healthy gingival fibroblasts, though the amount of DNA and protein per cell remained unchanged. In addition, all cultures (except Case 1) had a 2- to 3- fold increase of prolyl hydroxylase activity over that of the controls. As in the cases of prolyl hydroxylase activity, Case 1 did not show any change in collagen synthesis when compared to the control. However, Cases 2, 3, and 4 showed appreciable collagen increases in the cell and medium: 61% and 60% for Case 2; 16% and 36% for Case 3; and 21% and 80.7% for Case 4 respectively.

Adolescent↗
PubMed1997

Liposomes-coated hydroxyapatite and tricalcium phosphate implanted in the mandibular bony defect of miniature swine.

Hydroxyapatite and tricalcium phosphate have been used as bone implants for some period of time. Now unfortunately, these materials have failed to become the nucleation sites for bone regeneration. We hypothesized that coating hydroxyapatite and tricalcium phosphate with negatively charged liposomes may improve the nucleation process for new bone formation. The present study was designed to test this hypothesis. Experiments were carried out in 15 miniature swines' mandibular angle with artificial bony defects. In each of the swine, the bony defects on one side were implanted with either liposomes coated with hydroxyapatite or liposomes coated with tricalcium phosphate, while the other side served as control. At the end of the third and sixth weeks following the operation, we observed result, took histology and radiographs of the operated area. The results showed that liposomes-coated materials were biocompatible and their clinical endpoint was enhanced. At the end of the third week, the implant material was surrounded by dense connective tissues. At the end of the sixth week, there were new bone formations near the implanted material. In addition, liposomes which were immobilized in agarose gel and implanted in the defects showed new bony bridge formation. These observations suggest that liposomes have the ability in promoting repair of osseous deficiencies.

Alveolar Process↗
PubMed1997

[Multiple myeloma with oral manifestations--report of two cases].

Multiple myeloma is a neoplastic disorder of bone that originates from cells of bone marrow. It is most commonly seen within the age range of 50-80 years, cases under the age of 40 being rare. Men are affected more frequently than are women. Bone pain is the cardinal clinical symptom in multiple myeloma. Because of the destruction of bone, pathologic fracture is fairly common. In the oral manifestations, the mandible is involved far more frequently than the maxilla, especially the most active hematopoietic areas-the remus, angle and molar region of the mandible. Other signs and symptoms of jaw involvement include swelling, pain, and increased tooth mobility. Extraosseous lesions may result in paresthesia of soft tissue and gingival enlargement with bleeding tendency. Roentgenographic examination will usually reveal numerous punched-out lesions in a variety of bones. In addition, blood examination will reveal hyperglobulinemia and Bence-Jones protein may be present in the urine of myeloma patients. The histological features of myeloma are closely packed cells resembling plasma cells. Case 1 in this report is a 64-year-old female, who has been diagnosed as having multiple myeloma (IgG, lambda). She was referred to our hospital because of gingival swelling, bleeding and pain. Case 2 is a 60-year-old female suffering from spontaneous gingival bleeding. After blood, urine examination and bone marrow biopsy, multiple myeloma was diagnosed (IgG, lambda). This paper reports the clinical manifestations and treatment courses of these two cases, and the concerns of treatment of multiple myeloma are also discussed.

Female↗
PubMed1996

Antioxidant activity of natural flavonoids is governed by number and location of their aromatic hydroxyl groups.

We studied antioxidant activity of five natural flavonoids in canola oil, an emulsion, and rat red blood cell membrane. In the canola oil heated at 105 degrees C, myricetin most effectively attenuated lipid oxidation, followed by quercetin, morin and kaempferol in a decreasing order. When the emulsion containing canola oil was incubated at 54 degrees C, quercetin was most protective against lipid oxidation, followed by kaempferol, myricetin and morin in a decreasing rank. Apigenin demonstrated no antioxidant activity in either the canola oil or the emulsion. Of the flavonoids tested, quercetin was the best in quenching free radical chain reaction in rat red blood cell membrane. The antioxidative characteristics of these flavonoids was determined by multiple factors including the system used, the hydrophobicity, and the total number and the location of aromatic hydroxyl groups. We conclude that myricetin is an effective antioxidant in canola oil, while quercetin is an effective protector against lipid oxidation in the cell membrane.

Animals↗
PubMed1996

Chronic upper abdominal pain due to duodenal ulcer and other structural and functional causes: its localization and nocturnal occurrence.

The aim of the present study was to determine the degree of pain localization and frequency of nocturnal pain in duodenal ulcer and other causes of chronic upper abdominal pain. These parameters were prospectively recorded in a consecutive series of 1615 patients with chronic upper abdominal pain presenting to one gastroenterologist. The proportion of patients who were able to localize the site of their pain using a single finger was 13% for duodenal ulcer, 5% for gastric ulcer, 17% for biliary disease, 7% for functional dyspepsia and 8% for irritable bowel syndrome. The numbers of subjects with the above diagnoses who experienced nocturnal pain were 63, 63, 51, 41 and 58%, respectively. The sensitivity, specificity, positive predictive value and negative predictive value for duodenal ulcer were 13, 92, 14 and 91%, respectively, for localized pain; 63, 50, 11 and 93%, respectively, for nocturnal pain occurrence; and 9, 96, 20 and 90%, respectively, if the pain was both localized and nocturnal. If the pain was neither localized nor nocturnal, the corresponding values for the absence of duodenal ulcer disease were 49, 68, 93 and 13%, respectively. The pain of duodenal ulcer was therefore more likely to be nocturnal and well localized compared with pain from other causes. However, while the absence of these features made duodenal ulcer unlikely, their presence was less helpful in the diagnostic process.

Abdominal Pain↗
PubMed1995

How does chili cause upper gastrointestinal symptoms? A correlation study with esophageal mucosal sensitivity and esophageal motility.

Chili ingestion produces gastrointestinal symptoms in many subjects. Some of these symptoms, such as heartburn, might well arise from the esophagus, but the pathogenesis is unknown. We studied the effects of chili ingestion on esophageal motility in 16 healthy volunteers and correlated these with the production of chili-induced upper gastrointestinal symptoms. We also studied the effects of chili instillation into the esophagus in 15 of the subjects to determine whether typical symptoms were produced. There were no changes in esophageal manometric parameters in all 16 subjects after the ingestion of a chili suspension (5 g chili powder in 100 ml water), although half of them reported one or more symptoms. Direct instillation of the same chili suspension into the lower esophagus produced typical symptoms in all 15 volunteers tested. Chili-induced upper gastrointestinal symptoms were not accompanied by changes in esophageal motility. The esophageal mucosa itself was sensitive to chili, suggesting that at least some of the upper gastrointestinal symptoms produced by chili are mediated by direct stimulation of chili-sensitive afferent nerve endings in the esophageal mucosa.

Adult↗
PubMed1995

Treatment of hepatitis B surface antigen carriers in the early stage of the infection using recombinant alpha-interferon with steroid priming.

BACKGROUND: Alpha-interferon has been found to inhibit hepatitis B virus (HBV) replication in Chinese patients with chronic HBV infection although a sustained effect was rarely achieved in those with normal pretreatment serum alanine amino transferase (ALT) levels. Prednisolone priming has been found to be beneficial over treatment with interferon alone in these subjects. We studied the effect of steroid pre-treatment followed by recombinant interferon alpha-2a in the treatment of asymptomatic HBV carriers with positive hepatitis Be antigen (HBeAg), hepatitis B viral DNA (HBV-DNA) and minimal changes in liver histology. METHODS: The treatment regimen included a 6-week prednisolone priming, a 2 week rest followed by 14 weeks of three times weekly 9 mega units of interferon alpha-2a injection and 52 weeks of follow-up. There were seven patients in the treatment group and seven controls. RESULTS: The mean age, pre-treatment ALT (normal in all except for one in each of the treatment and control groups), HBV-DNA levels and histological scores were similar in the two groups. Serum HBV-DNA levels fell in six patients during treatment and became undetectable in two of them by the end. During follow-up, serum HBV-DNA returned to pre-treatment levels in all patients. None of the treated patients had HBeAg sero-conversion and none of the controls had spontaneous clearance of HBV-DNA or sero-conversion of HBeAg. No improvement of liver histology was observed in any of the treated patients. There were only mild flu-like side-effects noted and interferon alpha-2a was well tolerated at the doses given among treated patients. CONCLUSION: Prednisolone priming followed by interferon alpha-2a treatment has no beneficial effect on HBV carriers in the early stages of chronic hepatitis B infection.

Adult↗
PubMed1995

The effect of polyunsaturated phosphatidyl choline in the treatment of acute viral hepatitis.

BACKGROUND: Polyunsaturated phosphatidyl choline is a preparation often advocated for diseases of the liver. METHODS: In a randomized open controlled trial, a preparation of polyunsaturated phosphatidyl choline, at a dose of 900 mg orally daily, was given to 22 patients with acute viral hepatitis. A control group of 25 patients was not treated. RESULTS: Serial serum bilirubin and alanine amino transferase levels were measured up to 12 weeks. The falls in their levels after 2 and 5 weeks, and the lengths of time to their normalization, were not significantly different in the treated group compared to the control group. CONCLUSION: The results indicated that polyunsaturated phosphatidyl choline had no beneficial effect on the course of acute viral hepatitis.

Acute Disease↗
PubMed1995

Control of growth hormone (GH) binding protein release from human hepatoma cells expressing full-length GH receptor.

In humans and rabbits, the circulating GH binding protein (GHBP) is released from the GH receptor by cleavage at a site proximal to the cell surface. There is evidence that GHBP status is predictive of GH responsiveness, presumably because it reflects GH receptor status. This assumes that GHBP release is not a regulated step. Here we report a model for study of GHBP release that provides some insight into this question. Human HepG2 cells were stably transfected with rabbit GH receptor and shown to be responsive to nonprimate (bovine) GH, indicating functionality of the transfected receptor. These cells released GHBP of the expected size, and this release could be increased by incubation with a phorbol ester, which stimulated receptor synthesis through the cytomegalovirus promoter. We surveyed a wide range of protease inhibitors both with and without streptolysin-O permeabilization, with the intention of defining the endogenous protease. Of 16 inhibitors, only benzamidine proved an effective inhibitor of release, indicating the existence of a novel protease. We could increase GHBP release with a membrane impermeable thiol blocker, suggesting activation of a membrane protease. We examined the ability of IGF-1, insulin, dexamethasone, sex steroids, and T4 to influence GHBP release. Although these agents are known to be effective in the parent hepatoma line, none were effective in modulating GHBP release, although GH itself decreased release by around 30% as assessed with a ligand immunofunctional assay. We conclude that GHBP release appears to be constitutive in this model and driven by receptor availability. This is consistent with an in vivo situation where circulating GHBP provides an index of hepatic receptor expression.

Animals↗
PubMed1995

Immunogenicity and safety of an inactivated hepatitis A vaccine amongst Singaporeans.

The immunogenicity and reactogenicity of an inactivated hepatitis A virus (HAV) vaccine was studied in healthy Singaporean adult volunteers. One hundred and forty healthy volunteers with normal alanine (ALT) and aspartate (AST) transaminases and no previous exposure to HAV, received three 1 ml doses (720 ELISA units) of an inactivated HAV vaccine (Smithkline Beechams Biologicals) following a 0, 1, 6 months vaccination schedule. All subjects were asked to record and grade the severity of any reactions for three consecutive days after each dose. Serum ALT and AST as well as anti-HAV were measured at 0, 1, 2, 6 and 7 months after the first vaccine dose. Anti-HAV seroconversion occurred when levels rose above 40 mIU/ml. Eighty-five percent of vaccinees seroconverted after the first innoculation and 99% after the second injection. All vaccinees seroconverted after the third dose. Geometric mean anti-HAV titers (GMTs) were, respectively, 119, 391, 4406 mIU/ml one month after each of the three doses. The most common side effect was transient pain and tenderness at the vaccination site. No elevation of ALT or AST levels were noted during the study period. The inactivated hepatitis A vaccine used in this study is safe and highly immunogenic in the local adult population. Two doses one month apart appeared to give adequate protection.

Adult↗
PubMed1994

Characterization of 24-hour growth hormone secretion in acromegaly: implications for diagnosis and therapy.

OBJECTIVE: Early studies of acromegaly undertaken before the general availability of insulin-like growth factor I (IGF-I) assays have used arbitrary and varying growth hormone (GH) threshold levels for diagnosing and assessing outcome of treatment for this disease. We have undertaken a detailed study of GH secretion and its relationship to IGF-I levels to assess the usefulness of GH and IGF-I measurements in the assessment of acromegaly. PATIENTS: Thirty acromegalic subjects (12 untreated and 16 previously treated) and 30 age and sex-matched normal subjects were studied. MEASUREMENTS: Twenty-four-hour GH secretion was obtained from 20-minute sampling and serum IGF-I was measured. Comparisons were made of IGF-I, mean 24-hour GH concentration, and of the pulsatile and diurnal characteristics of GH secretion between the two groups. RESULTS: IGF-I levels in untreated acromegaly were elevated and clearly separated from the normal range. Mean 24-hour GH concentrations in untreated and treated acromegalic subjects with elevated IGF-I (> 40 nmol/l) were greater than (P < 0.01), and showed good separation from, those of normal subjects only after age-matching. From the 24-hour profiles, nadir GH levels in normal subjects fell below the level of detectability while those in untreated acromegalic subjects did not. Pulse amplitude (P < 0.01), ratio of pulsatile to non-pulsatile GH release and the night to daytime GH ratio (P < 0.05) were significantly reduced in acromegaly. In the six patients who attained normal IGF-I levels after surgery, pulsatile characteristics remained abnormal in four. Mean 24-hour GH was significant related (r = 0.57) to IGF-I. A random GH concentration > 2.5 micrograms/l (5 mIU/l) has a sensitivity of 77% and specificity of 95% in identifying acromegalic patients who have biochemically active disease (elevated IGF-I) after treatment. CONCLUSIONS: Patients with active acromegaly secrete more GH than age-matched normal controls. GH secretion in acromegaly is characterized by marked blunting of pulsatile secretion and, in contrast to normal subjects, the failure of GH to fall to undetectable levels at any time during the 24-hour day. IGF-I measurement is a more practical alternative in the diagnosis of acromegaly and in the assessment of therapeutic outcome. Since abnormalities of GH regulation may persist despite normalization of IGF-I, a distinction between remission and cure should be made. Detailed post-treatment evaluation of GH secretion is necessary to define the nature of underlying GH regulation and to evaluate the risk of disease recurrence.

Acromegaly↗
PubMed1994

Acute treatment of paroxysmal tachycardia by adenosine.

BACKGROUND: Adenosine has proven efficacy in clinical trials and in the electrophysiological laboratory for the treatment of paroxysmal tachycardia. AIMS: To evaluate the efficacy and safety of adenosine administered in a clinical setting by non-consultant staff. METHODS: Incremental doses of adenosine were administered intravenously to five children and 32 adults during 39 episodes of paroxysmal tachycardia in a clinical setting. Structural heart disease was present in 43% of patients. RESULTS: Of 35 episodes of narrow complex tachycardia, adenosine terminated 26 of 28 episodes of supraventricular re-entrant tachycardia (SVRT), one episode of ectopic atrial tachycardia, and induced transient atrioventricular block to reveal atrial arrhythmias in four. Termination of SVRT occurred at a mean (SD) dose of 9.2 (4.0) mg in adults and 0.09 (0.04) mg/kg in children, but two patients had later spontaneous reinitiation of SVRT. Two patients with narrow complex tachycardia who failed to respond to adenosine were subsequently found to have ventricular tachycardia. Adenosine was therapeutic or diagnostic in three of four episodes of broad complex tachycardia. Overall, by intention to treat by the clinician, adenosine was therapeutic or diagnostic in 34 of 39 episodes (87%). Breathlessness (26%), chest tightness (18%) and flushing (18%) occurred transiently. There were no episodes of hypotension. Adenosine was given safely to 15 patients in whom verapamil was considered contraindicated. CONCLUSIONS: Adenosine is a safe treatment for both narrow and broad complex tachycardias; usually effective for the former and diagnostic for the latter.

Acute Disease↗
PubMed1994

Central sleep apnea is associated with increased ventilatory response to carbon dioxide and hypersecretion of growth hormone in patients with acromegaly.

Although obstructive sleep apnea (OSA) occurs commonly in acromegaly, we have recently reported an unexpectedly high prevalence of central sleep apnea (CSA) in these patients. Acromegalic patients with CSA have increased growth hormone (GH) and insulin-like growth factor-1 (IGF-1) levels compared with their counterparts with OSA. Studies in animals, normal humans, and patients with sleep apnea have suggested that CSA is associated with increased gain of the respiratory control system. To examine the relationship between sleep apnea, respiratory control, and hormonal activity in acromegaly, we performed sleep studies and examined ventilatory responses to hypoxia at resting CO2 (HVR) and 8 mm Hg above resting CO2 (HHVR) and hypercapnia (HCVR) in 54 patients with acromegaly who also underwent detailed endocrine evaluation. Patients with CSA (n = 11) had higher HCVR (3.47 +/- 0.57 L/min/mm Hg) than did patients with obstructive sleep apnea (OSA) (1.86 +/- 0.19, n = 33) and patients without sleep apnea (1.77 +/- 0.21, n = 10). Measures of ventilatory control were all correlated with the mean of 12 hourly GH concentrations, but only HCVR was correlated with IGF-1 levels. Multiple linear regression analysis revealed that HCVR, HHVR, and IGF-1 could explain 39% of the variability in the degree of CSA in acromegalic patients with sleep apnea. We conclude that increased ventilatory responsiveness and elevated hormonal parameters of disease activity both contribute to the pathogenesis of central sleep apnea in acromegaly.

Acromegaly↗
PubMed1993

Potent effects of human galanin in man: growth hormone secretion and vagal blockade.

Human galanin (hGAL) is a 30-amino acid neurohormone that has recently been shown to differ significantly from porcine and rat GAL. We investigated the endocrine and cardiovascular effects of hGAL in eight male volunteers. On three separate occasions, each received a 90-min infusion of saline, low dose (33 pmol/kg.min) and high (132 pmol/kg.min) dose hGAL, combined with an iv glucose bolus (to assess effects on insulin and GH release). hGAL was undetectable, 1.4 +/- 0.2 nmol/L, and 3.7 +/- 0.5 nmol/L during control, low dose, and high dose studies, respectively. The half-life of hGAL was 3.5 +/- 0.5 min. GH levels rose significantly in both studies (vs. control) and were not suppressed by hyperglycemia [low dose area under the curve (AUC), 1827 +/- 348 micrograms/min.L (P < 0.05); peak, 19.5 +/- 5.3 micrograms/L; high dose AUC, 1896 +/- 401 micrograms/min.L (P < 0.005); peak, 28.0 +/- 7.5 micrograms/L]. PRL levels rose significantly with the high dose study only (AUC, 12.8 +/- 1.1 micrograms/min.L; P < 0.01). FSH, LH, and catecholamine levels were unchanged. Glucose-stimulated insulin release was not inhibited. There was a dose-dependent increase in pulse rate and a profound decrease in sinus arrhythmia, but no change in blood pressure. These cardiovascular effects have not been reported with studies in humans using GAL of other species. We conclude that hGAL may play an important role in man in modulating GH secretion and cardiac vagal tone, but not insulin release.

Adolescent↗
PubMed1993

Evaluation of the reproducibility and accuracy of ambulatory blood pressure monitoring using the Takeda TM-2420 automated blood pressure monitor.

The reproducibility of ambulatory blood pressure measurements was assessed in eight normotensive subjects who underwent three separate days of recording, using Takeda Medical TM-2420 (TM-2420) blood pressure monitors. The coefficients of variation of mean 24 hour systolic and diastolic blood pressure were 2.1% and 2.8% respectively. The corresponding values for systolic and diastolic blood pressure variability, were 19% and 14% respectively. Measurement intervals of greater than 30 minutes significantly reduced the reproducibility of mean day interval systolic measurements. The bias of the TM-2420 systolic and diastolic blood pressure measurements compared to standard sphygmomanometer measurement were 0 +/- 7 mmHg and 1 +/- 6 mmHg respectively. Ambulatory blood pressure monitoring provides reproducible estimates of mean systolic and diastolic blood pressure, however, blood pressure variability is poorly reproducible.

Adaptation, Physiological↗