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Biomedical subjects

S Ho

Publications and source records attributed to S Ho.

At least 37 records · Page 2Linked to original sources
PubMed2000

Immediate response of glenohumeral abduction range of motion to a caudally directed translational mobilization: a fresh cadaver simulation.

OBJECTIVE: To investigate the immediate effect of caudal glide translational mobilization on the range of motion (ROM) of passive glenohumeral abduction with a fresh cadaver model to simulate the mobilization movement performed by a physical therapist treating patients with glenohumeral hypomobility. DESIGN: Mechanical simulation of caudal glide mobilization and abduction torque range of motion (TROM) measurement of the glenohumeral joint with 2 material testing systems. Mobilizations were conducted with the glenohumeral joint positioned at a resting position (IGR) and at the end range of abduction (IGE). SETTING: Biomechanics laboratory. CADAVERS: Twenty fresh shoulder specimens from 10 cadavers (mean age, 68 +/- 8 yr). MAIN OUTCOME MEASURE: Changes in TROM of the glenohumeral abduction in response to 5 bouts of caudal glide mobilization. RESULTS: At least 3 repetitions of TROM were required to attain consistent measurements on glenohumeral abduction ROM. Significant differences were found among changes in TROM because of rest, IGR, and IGE (Kruskal-Wallis statistics, (chi2 = 14.58, p = .001). A greater increase in glenohumeral abduction TROM was found after IGE (mean +/- standard error of the mean, 4.38 degrees +/- 0.95 degrees) compared with the rest control (0.03 degrees +/- 0.07 degrees; Mann-Whitney test, p = .001, alpha = .017) or its IGR counterpart (0.26 degrees +/- 0.46 degrees, p = .001, alpha = .017). CONCLUSION: This simulation of caudal glide translational mobilization at the end range using cadaver models improved passive glenohumeral abduction ROM but was ineffective when performed with the shoulder placed in a resting position. The mechanical responses of the glenohumeral joint to translational mobilization in a live patient may be similar, but some caution should be used in generalizing these findings.

Aged↗
PubMed2000

Elevated tumour marker CA19-9: clinical interpretation and influence of obstructive jaundice.

AIMS: The tumour marker CA19-9 has been promoted as a reliable test for the detection of pancreatobiliary malignancy, yet its diagnostic role remains poorly defined. In this study the clinical interpretation of a raised serum CA19-9 level has been evaluated, with particular reference to obstructive jaundice. METHODS: One hundred and sixty-four patients with a CA19-9 level above 33 U/ml were studied. Serum CA19-9 was compared with clinical diagnosis and correlated with serum bilirubin level. In a subgroup of jaundiced patients (16 benign and 15 malignant cases), follow-up CA19-9 levels were determined 2 weeks after biliary drainage. RESULTS: The median CA19-9 level was lower in benign cases (102 (IQR 50-264) U/ml) than those with pancreatobiliary tumours (910 (IQR 263-6170) U/ml; P<0.01), although the overlap was substantial. In benign jaundiced cases, a positive correlation was observed between bilirubin and CA19-9 elevation (R=0.41, P<0.01). Relief of jaundice was associated with a fall in CA19-9 level in all benign cases and in nine of the 15 with malignancy. CONCLUSION: Confident discrimination between benign and malignant disease could not be made on the basis of a solitary elevated CA19-9 measurement. Hyperbilirubinaemia was associated with a further deterioration in specificity and caution is warranted when interpreting the results in jaundiced patients. Overall, only one half of patients with an elevated CA19-9 level ultimately proved to harbour a malignancy.

Adult↗
PubMed2000

Cryptotia.

Explore the source record for details and available documents.

Child↗
PubMed2000

Vegetarianism and ischemic heart disease in older Chinese women.

OBJECTIVE: This study compared the risk of ischemic heart disease among older vegetarian Chinese women with that of older non-vegetarian women. METHODS: 90 vegetarian Chinese women over 70 years old in Hong Kong were screened for ischemic heart disease by electrocardiogram (ECG) and cardiovascular questionnaire. They were compared with 90 non-vegetarian women of similar age examined in a previous local survey. The effects of confounding factors were adjusted by stepwise logistic regression analysis. RESULTS: The percentages of subjects with ischemic heart disease defined by symptoms and ECG or by ECG alone were significantly lower in vegetarian women (p <0.005 and p<0.05 respectively). Vegetarians had lower serum cholesterol levels: more were old age home residents and were less likely to perform regular exercise. On stepwise logistic regression, using probable ischemic heart disease defined by questionnaire and ECG as outcome measure, vegetarianism was the only significant predictor (OR 0.3, 95%CI 0.1-0.6, p<0.005). CONCLUSIONS: Vegetarian older Chinese women had lower risk of ischemic heart disease when compared with non-vegetarians. Apart from lower serum cholesterol levels, vegetarianism may have other protective factors against ischemic heart disease.

Age Factors↗
PubMed2000

Factors critical to the design and execution of epidemiologic studies and description of an innovative technology to follow the progression from normal to cancer tissue.

The results obtained from experimental studies of estrogen carcinogenesis need validation in epidemiologic studies. Such studies present additional challenges, however, because variations in human populations are much greater than those in experimental systems and in animal models. Because epidemiologic studies are often used to evaluate modest differences in risk factors, it is essential to minimize sources of errors and to maximize sensitivity, reproducibility, and specificity. In the first part of this chapter, critical factors in designing and executing epidemiologic studies, as well as the influence of sample collection, processing, and storage on data reliability, are discussed. One of the most important requirements is attaining sufficient statistical power to assess small genetic effects and to evaluate interactions between genetic and environmental factors. The second part of this chapter describes innovative technology, namely, Fourier transform-infrared (FT-IR) spectra of DNA that reveal major structural differences at various stages of the progression from normal to cancer tissue. The structural differences become evident from wavenumber-by-wavenumber statistical comparisons of the mean FT-IR spectra of DNA from normal to cancer tissues. This analysis has allowed distinguishing benign tissues from cancer and metastatic tissues in human breast, prostate, and ovarian cancers. This analysis, which requires less than 1 microg of DNA, is predicted to be used for detecting early cancer-related changes at the level of DNA, rather than at the cellular level.

DNA, Neoplasm↗
PubMed2000

Automatic optimization of resting and exercise atrioventricular interval using a peak endocardial acceleration sensor: validation with Doppler echocardiography and direct cardiac output measurements.

Peak endocardial acceleration (PEA) measured by an implantable acceleration sensor inside the tip of a pacing lead reflects ventricular filling and myocardial contractility. The contribution of the plateau phase of PEA as an indicator of optimal ventricular filling, hence of the appropriate atrioventricular interval (AVI) at rest and during exercise, was studied in 12 patients (age 69 +/- 6 years) with complete AV block and a PEA sensing DDDR pacemakers (Living 1 Plus, Sorin Biomedica). At a mean resting heart rate of 79 +/- 15 beats/min, the mean AVI optimized by PEA versus Doppler echocardiography (echo) were identical (142 +/- 37 vs 146 +/- 26 ms, P = 0.59). During submaximal exercise at a mean heart rate of 134 +/- 6 beats/min, AVI optimized by PEA was 135 +/- 37 ms. Cardiac output at rest, measured by the CO2 rebreathing method, was comparable with AVI determined by echo versus PEA (4.3 +/- 2.9 and 3.7 +/- 2.4 L/min, respectively), and increased to the same extent (8.0 +/- 3.9 vs 8.3 +/- 5.2 L/min) during submaximal exercise. In patients with AV block, AVI automatically set by PEA was comparable with AVI manually optimized by Doppler echocardiography and was associated with comparable exercise induced hemodynamic changes.

Aged↗
PubMed1999

The nature of the principal type 1 interferon-producing cells in human blood.

Interferons (IFNs) are the most important cytokines in antiviral immune responses. "Natural IFN-producing cells" (IPCs) in human blood express CD4 and major histocompatibility complex class II proteins, but have not been isolated and further characterized because of their rarity, rapid apoptosis, and lack of lineage markers. Purified IPCs are here shown to be the CD4(+)CD11c- type 2 dendritic cell precursors (pDC2s), which produce 200 to 1000 times more IFN than other blood cells after microbial challenge. pDC2s are thus an effector cell type of the immune system, critical for antiviral and antitumor immune responses.

CD40 Ligand↗
PubMed1999

Activity patterns and synaptic organization of ventrally located interneurons in the embryonic chick spinal cord.

To investigate the origin of spontaneous activity in developing spinal networks, we examined the activity patterns and synaptic organization of ventrally located lumbosacral interneurons, including those whose axons project into the ventrolateral funiculus (VLF), in embryonic day 9 (E9)-E12 chick embryos. During spontaneous episodes, rhythmic synaptic potentials were recorded from the VLF and from spinal interneurons that were synchronized, cycle by cycle, with rhythmic ventral root potentials. At the beginning of an episode, ventral root potentials started before the VLF discharge and the firing of individual interneurons. However, pharmacological blockade of recurrent motoneuron collaterals did not prevent or substantially delay interneuron recruitment during spontaneous episodes. The synaptic connections of interneurons were examined by stimulating the VLF and recording the potentials evoked in the ventral roots, in the VLF, or in individual interneurons. Low-intensity stimulation of the VLF evoked a short-latency depolarizing potential in the ventral roots, or in interneurons, that was probably mediated mono- or disynaptically. At higher intensities, long-latency responses were recruited in a highly nonlinear manner, eventually culminating in the activation of an episode. VLF-evoked potentials were reversibly blocked by extracellular Co2+, indicating that they were mediated by chemical synaptic transmission. Collectively, these findings indicate that ventral interneurons are rhythmically active, project to motoneurons, and are likely to be interconnected by recurrent excitatory synaptic connections. This pattern of organization may explain the synchronous activation of spinal neurons and the regenerative activation of spinal networks when provided with a suprathreshold stimulus.

Activity Cycles↗
PubMed1999

Spontaneous network activity transiently depresses synaptic transmission in the embryonic chick spinal cord.

We examined the effects of spontaneous or evoked episodes of rhythmic activity on synaptic transmission in several spinal pathways of embryonic day 9-12 chick embryos. We compared the amplitude of synaptic potentials evoked by stimulation of the ventrolateral funiculus (VLF), the dorsal or ventral roots, before and after episodes of activity. With the exception of the short-latency responses evoked by dorsal root stimulation, the potentials were briefly potentiated and then reduced for several minutes after an episode of rhythmic activity. Their amplitude progressively recovered in the interval between successive episodes. The lack of post-episode depression in the short-latency component of the dorsal root evoked responses is probably attributable to the absence of firing in cut muscle afferents during an episode of activity. The post-episode depression of VLF-evoked potentials was mimicked by prolonged stimulation of the VLF, subthreshold for an episode of activity. By contrast, antidromically induced motoneuron firing and the accompanying calcium entry did not depress VLF-evoked potentials recorded from the stimulated ventral root. In addition, post-episode depression of VLF-evoked synaptic currents was observed in voltage-clamped spinal neurons. Collectively, these findings suggest that somatic postsynaptic activity and calcium entry are not required for the depression. We propose instead that the mechanism may involve a form of long-lasting activity-induced synaptic depression, possibly a combination of transmitter depletion and ligand-induced changes in the postsynaptic current accompanying transmitter release. This activity-dependent depression appears to be an important mechanism underlying the occurrence of spontaneous activity in developing spinal networks.

Animals↗
PubMed1999

Cognitive effects of topiramate, gabapentin, and lamotrigine in healthy young adults.

OBJECTIVE: To study the acute and steady-state cognitive effects of three new antiepileptic drugs (AEDs): gabapentin, lamotrigine, and topiramate. BACKGROUND: Several newer antiepileptic medications approved recently by the Food and Drug Administration are gaining attention as efficacious alternatives to established AEDs. Greater tolerability with fewer side effects are reported in some. However, the potential cognitive effects of these newer AEDs have received limited attention. METHODS: Healthy young adults randomized to either of the three drugs were administered tests of attention, psychomotor speed, language, memory, and mood at baseline (predrug), acute single-dose period, and after 2 and 4 weeks on the drug. RESULTS: Compared with baseline, the topiramate group had selective, statistically significant declines on measures of attention and word fluency at acute doses, whereas the other two AED groups had no performance changes. At the 2- and 4-week test periods, only the topiramate subjects continued to display neurocognitive effects from drug administration. CONCLUSIONS: Results demonstrate potential acute and steady-state adverse cognitive effects for topiramate, whereas minimal effects were displayed for either gabapentin or lamotrigine in young healthy adults.

Acetates↗
PubMed1999

Phase II studies with DaunoXome in patients with nonresectable hepatocellular carcinoma: clinical and pharmacokinetic outcomes.

A total of 14 Chinese patients with inoperable hepatocellular carcinoma received a liposomal formulation of daunorubicin (DaunoXome) at a dose equivalent to 100 mg/m2 of the free drug every 3 weeks. Altogether, 12 patients were assessable for response; 2 patients had stable disease for 8 weeks, but all eventually developed progressive disease and there was no responder. The drug was well tolerated, with no evidence of cardiac toxicity being observed. Deterioration of liver-function tests was attributed to progressive tumors in the terminal stage of the disease. Pharmacokinetics studies revealed a biexponential decay for daunorubicin in association with mean initial and terminal half-lives of 1.8 and 7.4 h, respectively, and a mean total clearance of 15.0+/-5.5 ml/min. The AUC ratio between the metabolite daunorubicinol and daunorubicin was 0.07. These data differ markedly from the pharmacokinetics of the free drug.

Adult↗
PubMed1999

Mucin gene expression in the rat middle ear: an improved method for RNA harvest.

Mucins are heavily glycosylated proteins characterized by high molecular weight and heterogeneous structure. Mucin genes are expressed in a tissue- or epithelium-specific manner. Although mucins are known to be important structural components of the mucociliary transport system that protects epithelium against invading microorganisms, very little is known about mucin gene expression unique to the middle ear. This study demonstrated that middle ear messenger RNA specifically hybridized with rat MUC2 and human MUC2 (SMUC-41) complementary DNA probes. MUC3 and MUC5AC mucin genes, dominantly expressed in rodent intestine and trachea, were not detected in the rat middle ears in this study. The middle ear MUC2 messenger RNA harvested by lavage was characterized by a single transcript--unlike its counterpart in intestine and airways, which is characterized by polydispersity--suggestive of a better method for RNA analysis. It was concluded that rat middle ears possess a MUC2 mucin gene or homologue of human MUC2 (SMUC-41).

Animals↗
PubMed1999

Combating hepatocellular carcinoma with an integrated approach.

This short review summarizes an integrated approach to new methods of managing hepatocellular carcinoma (HCC) developed at our centre. HCC-specific isoforms of alpha-fetoprotein were detected by isoelectric focusing and their value in the differential diagnosis of early HCC on a background of chronic liver disease has been shown. Selective internal radiation therapy using yttrium-90 (90 Y) microspheres has been shown to be an effective treatment for inoperable HCC in a phase I and II study. A partition model for estimating the radiation doses from the 90 Y microspheres to the tumour and the non-tumorous liver during the therapy was then formulated, verified by correlating with intraoperative dosimetry, and evaluated in clinical settings. This permits 90 Y microspheres to be administered safely without the need of an open surgery and a randomized therapeutic controlled trial is in progress. Another randomized controlled trial using iodine-131 Lipiodol as a post-operative adjuvant therapy, aiming at reducing the recurrence rate is also on-going. HCC may be more effectively combated with a better understanding of its pathogenesis from chronic liver disease.

Carcinoma, Hepatocellular↗
PubMed1998

Internal radiation therapy for patients with primary or metastatic hepatic cancer: a review.

BACKGROUND: The limited efficacy of current approaches to the treatment of patients with hepatic cancer, including external beam radiation therapy and cytotoxic chemotherapy, has reawakened interest in the use of internal radiation therapy. METHODS: The authors reviewed series of patients with liver metastases or hepatocellular carcinoma (HCC) treated with 1) interstitial irradiation and direct intratumoral injection of 90Y microspheres, 2) intraarterial infusion of (131)I-Lipiodol, 3) intraarterial infusion of 90Y microspheres, or 4) parenteral administration of radiolabeled monoclonal antibodies. RESULTS: High dose rate interstitial irradiation with afterloading of (192)Ir resulted in local control of hepatic metastases for a median of 8 months and complete tumor eradication in 2 patients. Direct intratumoral injection of 90Y microspheres reduced the size of 90.6% of tumors and completely destroyed them in 8 patients. Treatment with arterial (131)I-Lipiodol resulted in a 17-92% response rate as well as a case of complete remission of unresectable HCC. It was found to be most effective against small tumors. No response was observed with liver metastases from colorectal carcinoma. Partial response was commonly achieved when patients with unresectable liver metastases or HCC were treated with intraarterial 9OY microspheres. Among four patients whose HCC became resectable following treatment with 90Y microspheres, two cases of complete remission were documented. In a prospective randomized trial, (131)I-antiferritin combined with chemotherapy was no more effective than chemotherapy alone. CONCLUSIONS: The different approaches to internal radiation therapy that are reviewed in this article represent several ways in which radiation can be selectively targeted to hepatic tumors without undue radiation to the nontumorous liver. However, the efficacy of each of these therapies still needs to be evaluated in randomized controlled trials.

Brachytherapy↗
PubMed1998

Human alpha1,3/4-fucosyltransferases. I. Identification of amino acids involved in acceptor substrate binding by site-directed mutagenesis.

In a previous study (Xu, Z., Vo, L., and Macher, B. A. (1996) J. Biol. Chem. 271, 8818-8823), a domain swapping approach demonstrated that a region of amino acids found in human alpha1, 3/4-fucosyltransferase III (FucT III) conferred a significant increase in alpha1,4-FucT acceptor substrate specificity into alpha1, 3-fucosyltransferase V (FucT V), which, under the same assay conditions, has extremely low alpha1,4-FucT acceptor substrate specificity. In the current study, site-directed mutagenesis was utilized to identify which of the eight amino acids, associated with alpha1,4-FucT acceptor substrate specificity, is/are responsible for conferring this new property. The results demonstrate that increased alpha1,4-FucT activity with both disaccharide and glycolipid acceptors can be conferred on FucT V by modifying as few as two (Asn86 to His and Thr87 to Ile) of the eight amino acids originally swapped from FucT III into the FucT V sequence. Neither single amino acid mutant had increased alpha1,4-FucT activity relative to that of FucT V. Kinetic analyses of FucT V mutants demonstrated a reduced Km for Galbeta1,3GlcNAc (type 1) acceptor substrates compared with native FucT V. However, this was about 20-fold higher than that found for native FucT III, suggesting that other amino acids in FucT III must contribute to its overall binding site for type 1 substrates. These results demonstrate that amino acid residues near the amino terminus of the catalytic domain of FucT III contribute to its acceptor substrate specificity.

Amino Acid Sequence↗