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Biomedical subjects

S T Ho

Publications and source records attributed to S T Ho.

At least 145 records · Page 8Linked to original sources
PubMed1990

Restriction site mapping for three or more enzymes.

Restriction site mapping requires a generator to put forward possible maps and a constraint checker to reject false maps. Ideally these combine to give an algorithm which calculates a sound and complete solution set. Three algorithms for generation are presented and compared. Two decompose a multi-enzyme problem (greater than or equal to 3) into subproblems. The constraint checker is based on separation theory. Some insights into the extent of constraint checking involved in and feasibility of more checking for three or more enzymes are discussed. The trade-off between computation time and the soundness of the solution set is examined.

Algorithms↗
PubMed1990

Opsonizing effect of normal cerebrospinal fluid on Staphylococcus aureus.

The opsonizing effect of normal cerebrospinal fluid (CSF) on Staphylococcus aureus has been demonstrated through phagocytic assay. Radiolabelled S. aureus was opsonized using various CSF preparations and then ingested by neutrophils. Uptake of S. aureus by neutrophils was 31 +/- 12% for untreated CSF, 28 +/- 14% for ethylene-glycol-bis(beta-aminoethyl ether) -N,N-tetraacetic acid(EGTA) chelation, 18 +/- 5% for heat-treated (50 degrees C), 14 +/- 8% for heat-inactivated (56 degrees C), 11 +/- 6% for S. aureus-absorbed, and 5 +/- 4% for heat-inactivated and S. aureus-absorbed, respectively. Indirect immunofluorescence antibody assay revealed that IgG was the class of immunoglobulins involved in the opsonic activity of CSF, and complement 3 (C3) deposition was weakly detected in S. aureus. These results suggest that both heat-labile (complement) and heat-stable (antibody) factors are crucial for the opsonization of S. aureus by normal CSF. We conclude that activation of the complement by S. aureus in normal CSF is through an alternative pathway and is enhanced by the presence of a specific antibody (IgG).

Cerebrospinal Fluid↗
PubMed1990

[Dose-response relationships of propofol in Chinese].

Propofol is a new intravenous anesthetic which possesses the rapid induction and recovery of anesthesia. It has been approved to be used in clinical anesthesia and critical care medicine since 1989. From the dose-response study of propofol, we can get the ED50 and induction dose of propofol and compare those with other anesthetics. Sixty young patients, ASA I-II, both sexes, were allocated into six groups of ten patients. All of patients did not receive premedicants. Groups I-VI were given intravenously over 25 sec 1.0 mg/kg, 1.2 mg/kg, 1.4 mg/kg, 1.6 mg/kg, 1.8 mg/kg and 2.0 mg/kg, respectively. Blood pressure and heart rate were monitored and recorded before and 1 min, 3 min, 5 min after the injection of propofol. Induction of anesthesia by propofol is considered to be successful as a patient closes his eyes and does not response to simple command. As a patient obeys the order to open his eyes, he is judged to emerge from anesthesia. Induction and recovery times were recorded in each successfully-induced patient. Data were analyzed using Litchfield and Wilcoxon, and Student's t tests. The ED50 of propofol was found to be 1.46 mg/kg (95% confidence interval: 1.35 mg/kg to 1.58 mg/kg). Induction and recovery times at 1.0 mg/kg, 1.2 mg/kg, 1.4 mg/kg, 1.6 mg/kg, 1.8 mg/kg and 2.0 mg/kg were 40 sec and 5.6 min, 38 sec and 6.0 min, 38 sec and 6.2 min, 36.8 sec and 6.7 min, 36.3 sec and 7.2 min, 35.5 sec and 7.2 min, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Transfusion-induced severe allergic reaction--report of one case].

Recently, improved cross-matching techniques have reduced the frequency of adverse reactions of blood transfusion less the 2%, but allergic reactions (non-hemolytic) occur in about 3% of patients receiving properly typed and crossmatched blood. Allergic reactions to blood or drugs administered during anesthesia represent an unpredictable and occasionally life-threatening event. When a severe allergic reaction develops, an aggressive and prompt treatment, including intravenous epinephrine, is necessary to minimize morbidity and mortality. We experienced a case of intraoperative shock due to blood transfusion. The case manifested with hypotension, tachycardia, cutaneous rash and bronchospasm during blood transfusion and then the aggressive treatment was given to resume normal vital signs. The rest of anesthesia and surgery as well as the recovery was uneventful and the patient was discharged on the 18th postoperative day.

Adult↗
PubMed1990

[The study of pretreatment with diphenylhydantoin or D-tubocurarine on succinylcholine-induced adverse effects].

Intravenous succinylcholine (SCh) is widely used as a muscle relaxant but it is often associated with adverse effects, including muscle fasciculations, postoperative myalgia, elevated serum potassium (K+) and creatine phosphokinase (CPK), etc. The present study was undertaken to evaluate the effects of pretreatment with Diphenylhydantoin (DPH) or d-Tubocurarine (d-TC) on SCh-induced adverse effects. 54 ASA I-II adult patients were randomly divided into 3 groups of 18 patients each. Four min before injection of SCh, group A received 1 ml of normal saline as a control group, group B DPH 2.5 mg kg-1 and group C d-TC 50 micrograms kg-1. Anesthesia was induced with thiopentone 3-4 mg kg-1 and then SCh was given to facilitate tracheal intubation. Anesthesia was maintained with isoflurane and nitrous oxide in oxygen. Muscle fasciculations, postoperative 24 hours myalgia, intubating conditions and levels of serum K+, CPK and DPH were recorded in every patient. All data were analyzed with Chi-Square and ANOVA tests. DPH and d-TC significantly decreased the incidence of fasciculations, whereas there were no differences regarding intubating condition, post-operative myalgia, and serum K+ among three groups. DPH concentration was 8.49 +/- 1.55 micrograms ml-1. Serum CPK was increased postoperatively in three groups. Pretreatment with DPH 2.5 mg kg-1 or d-TC 50 micrograms kg-1 effectively decreased SCh-induced fasciculations and did not affect intubating condition facilitated with SCh 1.5 mg kg-1. Nevertheless, these pretreatment did not improve postoperative myalgia and decrease serum CPK.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Evaluation of abdominal motor blockade using surface integrated electromyography during bupivacaine spinal anesthesia].

The study was undertaken to investigate abdominal motor blockade and compare sensory-motor differential blockade in bupivacaine spinal anesthesia by surface integrated electromyography (SIEMG). Seventeen physical status I adult male patients underwent lower limb surgery under spinal anesthesia were divided into two groups: hyperbaric bupivacaine (HB) group (n = 8) receiving 3 mL of 0.5% bupivacaine (8% glucose) and isobaric bupivacaine (IB) group (n = 9), 3 mL of 0.5% bupivacaine (glucose-free). Each patient was monitored with a blood pressure cuff, an ECG and a precordial stethoscope. Spinal anesthesia was performed at L3-4 interspace on the lateral position. Immediately following injection of bupivacaine, the patients were turned to the supine position and then simultaneous measurements of sensory blockade using pinprick, abdominal motor blockade at T6, T8, T10, T12 level using SIEMG and lower limb motor blockade using Bromage scale were made for 4 hours. Between two groups, there were no significant differences in terms of age, body weight, height as maximum level and mean times to maximum level of sensory blockade, abdominal motor blockade and lower limb motor blockade. The times of 2-segment regression of sensory blockade were 66.3 +/- 11.1 min in HB group and 115.6 +/- 31.3 min in IB group. The sensory-motor differential blockades were 4.6 +/- 0.5 segments and 4.8 +/- 2.1 segments in HB and IB groups, respectively. According to the linear regression analysis, the correlation between sensory blockade and abdominal motor blockade was better than the lower limb motor blockade and abdominal motor blockade. (Correlation coefficient (r): 0.893 vs 0.580 in HB group; 0.773 vs 0.366 in IB group).(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1989

Ultrastructural changes of the peripheral nerve induced by vibration: an experimental study.

To investigate the effects of vibration on the peripheral nerves, rabbits were exposed to vibration of 60 cycles/s frequency with 0.35 mm amplitude (acceleration: 51 m/s2) for two hours daily. After 150, 250, 450, and 600 hours vibration, thin sections of the saphenous and median nerves were examined under the electron microscope. Vibration was found to induce the following changes: (1) disruption of the myelin sheath and constriction of the axon, (2) accumulation of vacuoles in the nodal gap and paranodal region, (3) disorganisation of the paranodal end loops and detachment of the paranodal end loops from the axolemma, (4) dilatation of the Schmidt-Lanterman incisures (SLI) and increased density of SLI, and (5) disappearance of neurotubules and neurofilaments in axons. The diameters of myelin sheaths disrupted by vibration varied from 2 to 12 microns. The extent of the myelin disruption is proportional to the vibration dose.

Animals↗
PubMed1988

The mechanism of reducing thiopentone dose in elderly patients undergoing surgery.

The dose of thiopentone required to induce anesthesia in adults decreasing with age is not due to pharmacodynamic change. The change of pharmacokinetic properties of thiopentone with age in undergoing surgery patient's arterial blood was investigated in seven elderly (67-82 yr) and six young (21-33 yr) patients of both sexes. Thiopentone (3 mg kg-1) was administered intravenously and arterial blood samples were obtained immediately after the injection to measure plasma and red blood cell thiopentone concentrations by an HPLC method. Plasma protein binding was studied using ultracentrifuge method. The disappearance of thiopentone from the arterial blood was described by a two-compartment open model. The distribution rate constant (alpha) was significantly larger in the young patients (p less than 0.001). The distribution half-life was longer in the elderly (p less than 0.05). Both the input microscopic rate constant, K21, and the exit microscopic rate constant, K12, with the central compartment were significantly larger in the young patients. (p less than 0.02 and p less than 0.001, respectively). The difference between the exit and input microscopic rate constant, K12-K21, was much larger in the young patients (p less than 0.001). The plasma protein binding was significantly reduced in the elderly (p less than 0.05). The apparent overall volume of distribution, Vd was not significantly different between young and elder patients. However, the volume of distribution of the central compartment was smaller in the young patients (p less than 0.05). This was probably due to the difficulty of estimation of initial thiopentone plasma concentration post-equilibrium in the central compartment after administration of thiopentone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Acute effects of verapamil on neuromuscular transmission in patients with myasthenia gravis.

The effects of intravenous verapamil (18 micrograms, 36 micrograms, 72 micrograms kg-1) on neuromuscular transmission were studied in the integrated electromyographic (IEMG) responses of indirectly stimulated thenar muscles of five myasthenia gravis patients and 12 other patients without neuromuscular diseases anesthetized with thiopentone, pethidine and nitrous oxide in oxygen. In all subjects, verapamil 72 micrograms kg-1 significantly prolonged the P-R interval of the electrocardiogram from 0.122 +/- 0.004 to 0.152 +/- 0.005 sec and decreased the heart rate from 78.7 +/- 9.5 to 69.6 +/- 6.6 beat min-1, but it had no effect on arterial blood pressure. Verapamil 36 micrograms, 72 micrograms kg-1 significantly inhibited the IEMG to 84.50 +/- 3.30% and 79.25 +/- 3.52% of control value, respectively, in the myasthenia gravis patients. However, these doses did not influence the IEMG of normal subjects. The specific site and mechanism of verapamil's neuromuscular blocking action remain unclear. It is concluded that verapamil can produce neuromuscular blocking action in myasthenia gravis patients and that therefore caution is needed in administering verapamil to such patients.

Adult↗
PubMed1986

A study of neurophysiological measurements and various function tests on workers occupationally exposed to vibration.

Seventy male air grinder operators and 72 age-matched control workers were examined. Both groups of workers worked in the warm climate (20 degrees-33 degrees C) of southern Taiwan. None of the workers had symptoms of white fingers. The investigation program comprised: case history, physical examination, determination of maximal motor conduction velocity, proximal and distal sensory conduction velocity (NCV) of the median and ulnar nerves of the right upper extremity, measurement of skin temperature, nail press test, pain threshold and vibratory sense threshold of the upper extremities, and testing of the motor function. The dose-effect correlation between the NCV, various function tests and total operating time (TOT) was performed by multiple stepwise regression analyses. The regression analyses revealed a statistically significant correlation (dose/effect) between "the six NCV, vibratory sense threshold, pain threshold" and "age", as well as "TOT".

Adult↗