Biomedical subjects

P Y Tan

Publications and source records attributed to P Y Tan.

13 recordsLinked to original sources

PubMed2001

The WAND local anesthetic delivery system: a more pleasant experience for anal anesthesia.

PURPOSE: The WAND is a computer-controlled local anesthetic delivery system. Its use has been proven to be more comfortable for dental patients. The purpose of this study is to explore its applicability to anal procedures. Our hypothesis is that the WAND will provide greater comfort during anesthesia delivery while achieving the same anesthetic effect as traditional syringe technique. METHODS: Twenty patients with painless anal pathology were randomized to receive anal anesthesia using either the WAND or traditional syringe technique to a randomly selected half of the anoderm (right or left). The opposite side was then anesthetized by the alternate method, allowing patients to act as their own control. Objective and subjective pain scores were obtained from the patient after each mode of delivery. An independent observer interpreted the patient's tolerance by giving a subjective pain score. The volume of anesthetic used was recorded. Adequacy of anesthesia was tested by a pinch test. RESULTS: Sixteen (80 percent) of the 20 patients preferred the use of the WAND. Objective and subjective pain scores per the patients and subjective pain scores per the observer were significantly lower for the WAND than for traditional syringe technique (P < 0.05). The mean volume of local anesthetic used with the WAND was 1.7 ml compared with 3.2 ml for traditional syringe technique (P < 0.005). Anesthesia achieved with the WAND was as good as that achieved with traditional syringe technique when the pinch test was used. CONCLUSION: The WAND is as effective as the traditional syringe technique in the delivery of anal anesthesia while providing a more comfortable experience for the patient.

Adult↗

PubMed2000

The effect of lung injury and excessive lung fluid, on impedance cardiac output measurements, in the critically ill.

OBJECTIVES: To investigate the relationship between the attenuation of impedance cardiac output (IC(co)) measurements and lung fluid content in critically ill patients. DESIGN: Observational study. SETTING: Intensive Care Unit of a major teaching hospital in Hong Kong. PATIENTS: Twenty-four critically ill patients who required a pulmonary artery catheter. MEASUREMENTS AND MAIN RESULTS: Triplicate thermodilution cardiac output (TD(co)) and BoMed NCCOM3 (IC(co)) measurements were made simultaneously on a single occasion in each patient. Lung fluid accumulation was assessed by: (a) thoracic impedance (Zo), (b) radiological assessment of chest X-rays using an alveolar consolidation score (0-4) and (c) scoring the degree of hypoxia and use of positive end-expiratory pressure (PEEP). Offsets (TD(co)-IC(co))/TD(co), expressed as percentage, were compared with these indices of excess lung fluid. Patients were divided into those with sepsis (n = 13), fluid balance problems (n = 5) and cardiothoracic problems (n = 6). Mean cardiac output values were: 6.7 l/min TD(co) (range 3.6-12.9) and 5.2 l/min IC(co) (range 2.7-9.0). Overall the TD(co) and IC(co) values showed great variance, with a bias and limits of agreement of 1.49 +/- 4.16 l/min, or +/- 69%. In septic patients, increasing offset was correlated with decreases in Zo (r = 0.73, P = 0.005) and increases in alveolar consolidation score (r = 0.72, P = 0.005). CONCLUSIONS: The BoMed under-estimates cardiac output in critically ill patients. In septic patients the degree of attenuation of IC(co) can be related to the extent of lung injury and fluid accumulation within the thorax.

Adult↗

PubMed1991

Isoleucyl-tRNA synthetase of Methanobacterium thermoautotrophicum Marburg. Cloning of the gene, nucleotide sequence, and localization of a base change conferring resistance to pseudomonic acid.

The ileS gene encoding the isoleucyl-tRNA synthetase of the thermophilic archaebacterium Methanobacterium thermoautotrophicum Marburg was isolated and sequenced. ileS was closely flanked by an unknown open reading frame and by purL and thus is arranged differently from the organizations observed in several eubacteria or in Saccharomyces cerevisiae. The deduced amino acid sequence of isoleucyl-tRNA synthetase was compared with primary sequences of isoleucyl-, valyl-, leucyl-, and methionyl-tRNA synthetases from eubacteria and yeast. The archaebacterial enzyme fitted well into this group of enzymes. It contained the two short consensus sequences observed in class I aminoacyl-tRNA synthetases as well as regions of homology with enzymes of the isoleucine family. Comparison between the isoleucyl-tRNA synthetases of M. thermoautotrophicum yielded 36% amino acid identity with the yeast enzyme and 32% identity with the corresponding enzyme from Escherichia coli. The ileS gene of the pseudomonic acid-resistant M. thermoautotrophicum mutant MBT10 was also sequenced. The mutant enzyme had undergone a glycine to aspartic acid transition at position 590, in a conserved region comprising the KMSKS consensus sequence. The inhibition constants of pseudomonic acid, KiIle and KiATP, for the mutant enzyme were 10-fold higher than those determined for the wild-type enzyme. Both the mutant and the wild-type ileS gene were expressed in E. coli, and their products displayed the expected difference in sensitivity toward pseudomonic acid.

Amino Acid Sequence↗

PubMed1988

Vitamin A reserve of liver in health and coronary heart disease among ethnic groups in Singapore.

1. The vitamin A content of human liver tissue was determined in 363 autopsy samples. The sample comprised a total of 181 subjects dying after accidents and 182 dying from coronary heart disease among Singapore ethnic groups of both sexes. 2. The medium vitamin A reserve was 146 mg/kg in accident victims and 141 mg/kg in those who had died of coronary heart disease. Of all the samples 16% contained less than 40 mg/kg, 45% had 100-300 mg/kg, while 9% contained more than 500 mg/kg liver. 3. Among the accident victims, Indians had the lowest median liver vitamin A reserve (118 mg/kg) compared with that in other ethnic groups (137 mg/kg in Chinese, 191 mg/kg in Malays, 155 mg/kg in Caucasians). 4. The ethnic distribution of vitamin A reserve in coronary deaths was similar to that in accident victims. 5. There was no significant difference between the sexes in hepatic vitamin A reserve. 6. The distribution of vitamin A reserve in all the groups was skewed to the right.

China↗

PubMed1985

Energy balance study in Singapore medical students.

Energy cost of rest and various common daily activities was measured in 7 male and 16 female medical students by using a Max-Planck respirometer and a Lloyd's gas analysis apparatus. The average weight of male and female subjects during the course of the study was 67.3 +/- 14.2 and 51.2 +/- 5.1 kg, respectively. The average energy expenditure per day was estimated from a diary of activities for a period of 7 days. The average daily intake of energy was computed from food tables and based on weighed amounts of raw materials of food consumed over the same 7-day period when energy expenditure was determined. The average energy expenditure of rest and different activities was found to be significantly lower than the figures published for western subjects. The daily energy intake and expenditure were 2,138 +/- 217 kcal (9.0 +/- 0.9 MJ) and 1,894 +/- 168 kcal (8.0 +/- 0.7 MJ), respectively, in male medical students, giving a positive balance of 244 kcal (1.0 MJ). The values of the same in female medical students were 1,711 +/- 292 kcal (7.2 +/- 1.2 MJ) and 1,474 +/- 211 kcal (6.2 +/- 0.9 MJ) with a balance of 237 kcal (1.0 MJ).

Adolescent↗

PubMed1985

Preparation of bovine blood coagulation factors X1 and X2.

A method is described for the preparation of both Factor X1 and Factor X2 from citrated bovine blood. The proteins from the plasma were first adsorbed on barium citrate by adding barium chloride solution. The precipitate formed was stirred with citrate/NaOH pH 6.9 buffer; barium and other clotting factors were removed by adding ammonium sulphate (up to 30% saturation) to the suspension. The Factor X was then precipitated by 65% ammonium sulphate, after resolution in citrate buffer chromatographed on DEAE-Sephadex and purified by rechromatography on DEAE-Sephadex and DEAE-Sepharose, respectively. This yielded Factor X1 and Factor X2 with respective purifications of about 16 000 and 24 000-fold that of the plasma. The apparent molecular mass of both Factor X1 and Factor X2 was 55 kDa as estimated by the sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Factor X2 had a higher specific biological activity of about 340 000 units/mg compared to that of Factor X1 of about 230 000 units/mg.

Animals↗

PubMed1983