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Biomedical subjects

W H Liu

Publications and source records attributed to W H Liu.

At least 55 records · Page 3Linked to original sources
PubMed1992

Production of androsta-1,4-diene-3,17-dione from cholesterol using immobilized growing cells of Mycobacterium sp. NRRL B-3683 adsorbed on solid carriers.

Living cells of Mycobacterium sp. NRRL B-3683 were immobilized by adsorption on different types of solid carriers in order to produce androsta-1,4-diene-3,17-dione (ADD) from cholesterol. Activated alumina proved to be the most preferred carrier for long-term operation when glucose and peptone were added to the reaction medium. In a repeated-batch process, the maximum productivity of ADD was about 0.19 g/l per day with a molar conversion rate of 77% when 1.0 g/l of cholesterol was added to the reaction medium. The half-life of the immobilized cells was more than 45 days and the system could be reactivated by incubating the immobilized cells in a cell growth medium.

Adsorption↗
PubMed1992

Therapeutic suggestions during general anaesthesia in patients undergoing hysterectomy.

In a double-blind, randomized study, we have examined the influence of positive therapeutic suggestions, presented to anaesthetized patients undergoing total abdominal hysterectomy, on postoperative morbidity and duration of hospital stay. Seventy-five patients were allocated randomly to be exposed to one of three tapes containing positive therapeutic suggestions, a modified history of the Queen's Medical Centre, or no message. We found that neither therapeutic suggestions nor the presence of a voice during anaesthesia improved postoperative outcome or reduced duration of hospital stay after total abdominal hysterectomy.

Adult↗
PubMed1992

Factors influencing epidural catheter migration.

The incidence and amount of migration of epidural catheters was investigated in a prospective randomised study of 153 women who required analgesia in labour. Inward or outward migration occurred in 36% of patients. Inward migration by 1-3 cm occurred in 21 (13.7%) patients and outward migration by 1 cm or more occurred in 34 (22.2%); three (2%) catheters migrated out through the skin. There were significant positive correlations between outward migration and weight, body mass index, and depth of the epidural space. There was no relationship between migration and height, age, intervertebral space used or duration of catheterisation. Problems with epidural block were no more likely in patients in whom migration of 1 cm or more occurred compared with those in whom migration was limited to a maximum of +/- 0.5 cm. However, the pattern of problems was different. All cases of failed epidural block occurred in patients whose epidural catheter migrated outward by 2.5 cm or more. Unilateral blockade was not more likely if migration of 1 cm or more occurred.

Adhesives↗
PubMed1992

Antihypertensive effects of m-nisoldipine and nisoldipine on conscious renal hypertensive rats and dogs.

The antihypertensive effects of m-nisoldipine (m-Nis) and nisoldipine (Nis) by ig 0.3, 1.0, 3.0 and 1.0, 3.0, 9.0 mg.kg-1 respectively on renal hypertensive rats (RHR) and 0.1, 0.3, 1.0 mg.kg-1 orally (for both drugs) on renal hypertensive dogs (RHD) were studied. Both m-Nis and Nis depressed blood pressure (BP) dose-dependently in RHR and RHD. The reduction of blood pressure correlated well with the m-Nis concentration in plasma of RHD. On the basis of ED20 (HR)/ED20 (BP), the hypotensive effect of m-Nis on systolic blood pressure (SBP) was only 1.6 times as great as that of Nis on RHR (P less than 0.05), but in RHD, both drugs showed the same potency (P greater than 0.05). In both models, m-Nis showed much more potent effect on diastolic blood pressure (DBP) than Nis (P less than 0.01), and possessed stronger hypotensive effects on DBP than on SBP (P less than 0.05 and P less than 0.01); but for Nis, its effects on SBP and DBP appeared to be in the same order (P greater than 0.05). The fall in BP was accompanied by a transient increase of heart rates (HR) with m-Nis and Nis in RHR and RHD. The chronic antihypertensive effects of m-Nis and Nis were also remarkable with 1.0 mg.kg-1 daily at 9 AM for 21 d. During this period, the BP and HR lowered to nearly normal level. After withdrawal of m-Nis and Nis, the hypotensive effects lasted nearly 1 wk.

Animals↗
PubMed1991

Location of ion-binding sites in the gramicidin channel by X-ray diffraction.

We report the first X-ray diffraction on gramicidin in its membrane-active form by using uniformly aligned multilayer samples of membranes containing gramicidin and ions (T1+, K+, Ba2+, Mg2+ or without ions). From the difference electron density profiles, we found a pair of symmetrically located ion-binding sites for T1- at 9.6 (+/- 0.3) A and for Ba2+ at 13.0 (+/- 0.2) A from the midpoint of the gramicidin channel. The location of Ba(2+)-binding sites is near the ends of the channel, consistent with the experimental observation that divalent cations do not permeate but block the channel. The location of T1(+)-binding sites is somewhat of a surprise. It was generally thought that monovalent cations bind to the first turn of the helix from the mouth of the channel. (It is now generally accepted that the gramicidin channel is a cylindrical pore formed by two monomers, each a single-stranded beta 6.3 helix and hydrogen-bonded head-to-head at their N termini.) But our experiment shows that the T1(+)-binding site is either near the bottom of or below the first helix turn.

Binding Sites↗
PubMed1991

Comparison of contemporaneous and retrospective assessment of postoperative pain using the visual analogue scale.

We have assessed postoperative pain in 50 patients who had undergone total abdominal hysterectomy, using repeated contemporaneous and single retrospective visual analogue scores. There were significant correlations between the median, mean and greatest contemporaneous scores, and the single retrospective scores, but there was a wide scatter of results among and within individual patients. We conclude that the wide variability between the two methods of assessment suggests that the two techniques should not be used interchangeably.

Adult↗
PubMed1991

The effect of prophylactic fentanyl on shivering in elective caesarean section under epidural analgesia.

The aims of this randomised double-blind study were to investigate whether 25 micrograms of fentanyl administered prophylactically by the epidural route would influence the incidence of shivering in parturients who underwent elective Caesarean section under epidural analgesia and whether it would affect the axillary and calf temperatures. There was a 50% reduction (p less than 0.05) in the overall incidence of shivering in patients who received fentanyl and there was some evidence to suggest that low-dose epidural fentanyl might reduce shivering by an influence on thermoregulation.

Adolescent↗
PubMed1991

Incidence of awareness with recall during general anaesthesia.

One thousand patients who were anaesthetised between February and April 1990 at University Hospital, Nottingham were interviewed between 20 and 36 hours after their operation. Patients under 16 years of age, those who had undergone obstetric or intracranial surgery, those who were unable to communicate and patients who were discharged from hospital before the postoperative visit were not interviewed. A standard set of questions was used to determine the incidences of recall of events and dreams during the operation. These incidences were 0.2% and 0.9% respectively, considerably lower than reported in previous comparable studies.

Adult↗
PubMed1991

[Association of HLA antigens with thyrotoxic periodic paralysis].

Periodic paralysis is a rare and peculiar complication of thyrotoxicosis, especially in Chinese and Japanese patients. The susceptibility to autoimmune thyroid disease has recently been reported to be strongly linked with certain immunogenetic factors. The objective of this study was to seek a genetic marker by HLA typing in Chinese patients with thyrotoxic periodic paralysis (TPP). The distribution of HLA-A, B, C, DR and DQ antigens in 20 thyrotoxic patients with periodic paralysis and 51 thyrotoxic patients without periodic paralysis was compared with that in 100 controls. The results showed that among the patients with TPP, these was a highly significantly increase of HLA-B51 frequency and B51 appeared to be linked with Cw3 in a state of dysequilibrium.

Adult↗
PubMed1989

[Acute toxicity testing (LD50) of Chinese mineral drugs].

Acute toxicity and LD50 of 62 mineral drugs were determined by ig, ip or iv in mice, in order to provide some guidelines for safety in clinical use, as well as for pharmacological and toxicological studies. In the present investigation, the difference in the acute toxicity and LD50 between raw drugs and medicines prepared by roasting is explained.

Animals↗
PubMed1989

Production of dodecanedioic acid from n-dodecane by yeasts.

In order to develop a process for production of dodecanedioic acid (DC-12) as starting materials for the chemical industry, a n-dodecane assimilating and DC-12-producing yeast was isolated from Taiwan soil. The taxonomical characteristics of this newly isolated yeast were examined and it was identified as Candida tropicalis NTU-512. The newly isolated strain was improved successively by NTG mutagenesis. A high potency DC-12-producing mutant 91 which showed slight growth both in DC-12 and n-dodecane enrichment media was isolated. The DC-12 productivity of mutant 91 reached 3,326 mg/I by shaking culture at 30 degrees C for 72 h. This figure is 2.5-fold that of the parent strain (1,310 mg/I).

Alkanes↗
PubMed1987

Radiation hormesis: its expression in the immune system.

The effects of low-dose single and continuous whole-body irradiation on immune functions were studied in C57BL/6 mice. Plaque-forming cell reaction of the spleen was found to be stimulated by single doses of x rays in the range of 0.025 to 0.075 Gy and by continuous exposure to gamma rays with a cumulative dose of 0.065 Gy. The reactivity of thymocytes to interleukin 1 showed a dose-dependent depression in the dose range of 0.025 to 0.25 Gy, but there was an increase in cell number in the thymus between doses of 0.025 and 0.10 Gy, resulting in enhancement of reaction of the whole organ. Unscheduled DNA synthesis of spleen cells was stimulated by single irradiation with 0.05 Gy and continuous irradiation with a cumulative dose of 0.13 Gy. The implications of these immunologic changes under low-dose radiation are discussed.

Animals↗