Biomedical subjects

K F Ng

Publications and source records attributed to K F Ng.

51 records · Page 3Linked to original sources

PubMed1997

An audit of the safety of an acute pain service.

We audited and analysed the adverse effects and safety of postoperative pain management on 2509 consecutive patients under care of the Acute Pain Service at a tertiary referral teaching hospital over a 32-month period. Our standard respiratory monitoring consisted of continuous pulse oximetry, hourly respiratory rate counting, sedation scoring and intermittent arterial blood gas sampling. This protocol was reliable and detected six episodes of bradypnoea, 13 of hypercapnia and 23 of oxygen desaturation occurring in 39 patients (1.8% of all spontaneously breathing patients). Two patients required naloxone injection and none had long-term sequelae. Hypotension due to epidural bupivacaine 0.0625% and fentanyl 3.3 micrograms.ml-1 infusion occurred in four patients (1.2%), all with a sensory block higher than T5. They readily responded to fluid infusion and ephedrine (two patients). Postoperative nausea or vomiting occurred in 723 (28.8%) and 380 (15.1%) patients, respectively. Odds ratio analysis showed that the risk factors for postoperative nausea and vomiting were: female gender, gynaecological operations, nongeriatric patients and systemic analgesia. Postoperative nausea and vomiting decreased analgesic efficacy by discouraging the use of patient-controlled analgesia and was regarded as equally distressing as pain. Other side-effects included: pruritus in 182 patients; dizziness in 333 and lower limb weakness in 73 (21.2% of patients receiving epidural local anaesthetics). It is concluded that a standard monitoring and management protocol, an experienced nursing team and reliable Acute Pain Service coverage is mandatory for the safe use of modern analgesic techniques.

Aged↗

PubMed1997

Epidural infusion of bupivacaine 0.0625% plus fentanyl 3.3 micrograms/ml provides better postoperative analgesia than patient-controlled analgesia with intravenous morphine after gynaecological laparotomy.

One hundred and twenty women undergoing gynaecological abdominal operations were randomized to receive either epidural bupivacaine 0.0625% + fentanyl 3.3 micrograms/ml infusion (Group EPI, n = 57), or patient-controlled intravenous morphine analgesia (Group PCA, n = 54) for postoperative pain relief. The groups were comparable in demographic data, types and duration of operation. Group EPI achieved significantly lower verbal rating scale of pain (VRS) at rest at 0, 4, 12, 16, 20, 28 and 40th postoperative hours. The VRS during cough were also significantly lower in Group EPI at 0, 4, 8, 12, 28 and 36th postoperative hours. None of the patients had respiratory depression or hypotension. Nausea/vomiting occurred in 52.6%/33.3% of patients in Group EPI and 52.7%/37.0% in Group PCA. Most patients (84.2% in Group EPI and 72.2% in Group PCA) rated their pain management as "good". We conclude that epidural infusion of bupivacaine 0.0625% and fentanyl 3.3 micrograms/ml provide better analgesia than patient-controlled intravenous morphine after gynaecological laparotomy.

Analgesia, Epidural↗

PubMed1996

The bamboo skewer: airway management in a patient with penetrating injury of the floor of mouth.

PURPOSE: To report a safe airway management option in patients with penetrating injury of the floor of the mouth, reinforcing the similar experience of others and illustrating the importance of proper assessment and planning before airway negotiation. CLINICAL FEATURES: A 23-yr-old man was admitted with a penetrating injury of the floor of mouth caused by falling on bamboo and with the foreign body in situ. The extent of penetration could not be assessed clinically but computerized tomography (CT) was used to assist in preoperative evaluation of the airway. After atropine iv, fentanyl iv, topical cocaine and lidocaine spray, awake fibreoptic guided nasal intubation was performed successfully and the patients airway secured before induction of anaesthesia. Elective tracheostomy was performed postoperatively which was removed on day 5. Post-operative recovery was uneventful. CONCLUSION: Awake fibreoptic guided nasal intubation was useful in managing the airway of a patient with a penetrating injury of the floor of mouth and foreign body in situ. Thorough previous evaluation of the patients airway by CT scan, careful topicalisation of the airway, and judicious use of iv sedation and anti-sialogue contributed to the safe and successful airway management.

Adult↗

PubMed1996

The development of hypercoagulability state, as measured by thrombelastography, associated with intraoperative surgical blood loss.

Thrombelastographic evidence of hypercoagulability, including shortening of r-time (P < 0.01); shortening of k-time (P < 0.01); and widening of trace angle (P < 0.01) were observed in a group of 21 Chinese surgical patients when (a) the amount of blood loss was at an estimated 10% of total blood volume and (b) the amount of blood loss was at an estimated 15% of blood volume. The amount of blood loss was documented by haemoglobin measurements. No evidence of hypercoagulability was observed at around one hour into the operation in the absence of bleeding. We conclude that a mild to moderate degree of surgical blood loss with haemodilution is associated with the development of hypercoagulability as measured by thrombelastography. Further studies looking at the thrombebolic outcome in such groups of patients is warranted. It is also suggested that caution should be exercised in the use of intraoperative isovolaemic haemodilution until the phenomenon is further investigated.

Adult↗

PubMed1996

The efficacy, applicability and side-effects of postoperative intravenous patient-controlled morphine analgesia: an audit of 1233 Chinese patients.

We analyzed data from 1233 Chinese patients of a wide age range who received patient-controlled analgesia (PCA) intravenous morphine for postoperative pain relief, during the period of January 1992 to May 1995. The analgesic regimen was standardized as follows: PCA bolus 1 to 1.5 mg; lock-out interval 5 minutes; one-hour maximum dose 0.075 to 0.1 mg.kg-1 and background infusion 0 or 0.5 mg.h-1. Most patients underwent major surgery that was broadly subclassified according to the anatomical area involved. The median verbal numerical rating scales of pain (0 to 10) at rest and while coughing for the first, second and third 24 hours were 3.0/5.0, 1.5/4.0 and 0/3.0 respectively and the corresponding demand to delivery ratios were 2.8 +/- 2.9, 2.6 +/- 2.4 and 2.4 +/- 2.6. The overall morphine consumptions in 1004 of these Chinese patients were 27.5 +/- 16.8, 17.8 +/- 16.1 and 18.1 +/- 21.0 micrograms.kg-1.h-1 during the first 16, 17 to 41 and 42 to 66 postoperative hours respectively. These figures were the same as for Caucasian patients managed in the same institution. Morphine consumption was significant higher following thoracic, upper abdominal and spinal surgery. Also it was higher in patients younger than 65 years, males, cigarette smokers and those with ASA physical status I or II. The commonest side-effects were nausea (34.5%) and vomiting (18.2%). Bradypnoea and oxygen desaturation occurred in 0.5% and 1.6% respectively. All cases were promptly detected and managed with no adverse outcomes. Most patients were satisfied (76.7% ranked "good") with their postoperative analgesia. The commonest reasons for dissatisfaction were inadequate pain relief, nausea and reluctance to self-control analgesic administration. It is concluded that PCA with intravenous morphine is effective and safe as a routine postoperative technique for Chinese surgical patients.

Aged↗

PubMed1996

Malakoplakia of urinary tract: report of two cases with emphasizing the histologic spectrum and the morphogenesis of Michaelis-Gutmann bodies.

Two cases of urinary tract malakoplakia, one in right kidney and the other one in urinary bladder, were reported. Both cases affected middle-aged female patients with long-term urinary tract infection. Their clinical presentation simulated a neoplasm. The diagnosis entirely depended on pathologic examination. The former case also extensively involved the retroperitoneum, liver and duodenum. The latter case was unusually associated with Pseudomonas infection. Electron microscopy showed that the morphogenesis of Michaelis-Gutmann bodies occurred within the phagolysosomes. Initially, small myelin-like figures-containing phagolysosomes were undergoing to fuse to form a large one. Then, the membranous fragments and myelin-like figures served as nucleation sites. The nucleation sites could be multiple in the same phagolysosome. Needle shaped crystalline material began to deposit by unknown mechanism. Finally, mature Michaelis-Gutmann bodies were well formed. But no bacteria were identified. The two cases were successfully managed with surgical resection then sulfamethoxazole-trimethoprim treatment. Finally, it was emphasized that frozen section of tumor biopsy avoided unnecessary radical surgery in the latter case.

Female↗

PubMed1995

A clinical audit for postoperative pain control on 1443 surgical patients.

BACKGROUND: Moderate to severe pain occurs in 75 to 100% of patients after major operations. Pain control techniques, for examples the patient controlled analgesia (PCA) and epidural analgesia, are effective in relieving postoperative pain. Routine delivery of these pain control techniques to patients undergoing operations can be provided by an anaesthesiologists-based acute pain service (APS). METHODS: This manuscript audited postoperative pain management service to 1369 ethnic Chinese patients and 74 patients of other races, over a 30 mon period in a teaching hospital in Hong Kong. The APS was prioritized to elderly patient (36.1%, aged 65 or higher), patients of poor physical condition (27.0% ASA III or IV) and those undertaken major operations. Most patients (1348, 93.4%) received either one of the four standardized analgesic regimens including PCA or epidural analgesia. RESULTS: The median verbal quantitative scale of pain (VQS) at rest/movement were 2.0/4.3 on operative day and 0/0.6 on 4th postoperative day. The morphine consumption in 665 Chinese patients (PCA intravenous morphine) was 26.1 +/- 14.3 mg/kg/h (mean +/- SD) during the first 20 postoperative hours. This decreased to 18.1 +/- 15.1 at 21th to 44th and 18.5 +/- 14.9 at 45th to 68th hours postoperatively. There was no difference in morphine consumption between Chinese patients and other races. The incidence for nausea and vomiting were 26.5% and 13.3%, respectively. Respiratory derangement occurred in 23 patients (1.9%) and almost always accompanied by somnolence. Most patients (1176, 81.5%) rated their postoperative analgesia on discharge from the care of APS. CONCLUSIONS: Effective and safe postoperative analgesia in Chinese patients can be achieved with currently available pain control techniques such as epidural and PCA. APS is a practicable approach to deliver these techniques to postoperative patients on a routine basis.

Adult↗

PubMed1994

Photoaffinity labelling of Plasmodium falciparum proteins involved in phospholipid transport.

Erythrocytes infected with mature-stage malaria parasites accumulate phospholipids from exogenous sources. We show that the transport of N-(7-nitrobenzy-2-oxa-1,3-diazol-4-yl)-1,2- dipalmitoyl-sn-glycero-3-phosphatidylethanolamine (N-NBD-DPPE), from the erythrocyte membrane to the intracellular malaria parasite, is dependent upon metabolic energy. A photoreactive phospholipid analogue, N-[125I]iodo-4-azidosalicylamidyl-1, 2-dilauryl-sn-glycero-3-phosphatidylethanolamine (N-125I-ASA-DLPE), has been synthesised and used in an attempt to identify proteins involved in phospholipid trafficking in malaria-infected erythrocytes. This photoreactive probe was found to preferentially label a protein with an apparent molecular weight of 22 kDa. Photolabelling of the 22-kDa protein was enhanced upon ATP depletion of malaria-infected erythrocytes.

Adenosine Triphosphate↗

PubMed1991

The beta-glucan synthase from Lolium multiflorum. Detergent solubilization, purification using monoclonal antibodies, and photoaffinity labeling with a novel photoreactive pyrimidine analogue of uridine 5'-diphosphoglucose.

The membrane-bound beta-glucan synthase from Italian ryegrass (Lolium multiflorum L.) endosperm cells has been solubilized by both non-ionic and zwitterionic detergents. A complex relationship exists between the ratio of (1----3)-, (1----4)-, and (1----3, 1----4)-beta-glucan products of the solubilized enzyme, the cations present, and the concentration of the uridine 5'-diphosphoglucose substrate. Monoclonal antibodies directed against the beta-glucan synthase complex were generated by immunization of mice with an unfractionated microsomal reparation. Hybridoma cell lines were screened using a combination of indirect enzyme-linked immunosorbent assay followed by an enzyme-capture assay. The purified monoclonal antibodies were used with Pan-sorbin (stablized protein A-bearing staphylococcal cells) to immunoprecipitate an active beta-glucan synthase complex which had been solubilized from a microsomal preparation with 0.6% CHAPS. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the immunoprecipitated synthase complex revealed four major polypeptides of apparent molecular mass 30, 31, 54, and 58 kDa together with several minor components. The immunoprecipitated beta-glucan synthase complex was capable of synthesizing both (1----3)- and (1----4)-beta-glucans. A new photoreactive pyrimidine analogue of uridine 5'-diphosphoglucose, 5-[3-(p-azidosalicylamide]allyl-uridine 5'-diphosphoglucose was synthesized in a three-step reaction sequence involving mercuration of UDP-Glc, alkylation of 5-Hg-UDP-Glc, and acylation of 5-(3-amino)allyl-UDP-Glc and characterized by chemical and spectroscopic analysis. The analogue inhibits (Kiapp 16 microM) and, upon UV irradiation, irreversibly inactivates the beta-glucan synthase. The analogue was iodinated with Na125I to give a radiolabeled, photoreactive compound, and was used in photoaffinity labeling of UDP-Glc pyrophosphorylase, UDP-Glc dehydrogenase, and several putative UDP-Glc-binding proteins from L. multiforum. The radiolabeled analogue specifically labeled the 31-kDa polypeptide in the immunoprecipitated synthase complex. The photolabeling of this polypeptide is strictly dependent on UV irradiation, is blocked by uridine 5'-diphosphoglucose and uridine 5'-diphosphate, and reaches saturation at analogue concentrations above 300 microM. These results indicate that the 31-kDa polypeptide in the beta-glucan synthase complex bears a uridine 5'-diphosphoglucose-binding site and is involved in the catalysis of beta-glucan synthesis.

Affinity Labels↗

PubMed1989

Solubilization and partial purification of hyaluronate synthetase from oligodendroglioma cells.

Hyaluronate synthetase was solubilized with digitonin from crude membranes of mouse oligodendroglioma cells. Detergent extraction was carried out in 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid-buffered saline with an optimal digitonin to protein ratio (w/w) of 0.7-0.8. The solubilized synthetase was partially purified approximately 230-fold by gel filtration and ion-exchange chromatography. The solubilized enzyme displayed similar properties to membrane-bound enzyme: (a) it synthesized high molecular weight hyaluronate which eluted in the void volume of a Sepharose CL-2B column; (b) the apparent Km values obtained for UDP-GlcUA and UDP-GlcNAc were 50 and 100 microM, respectively; and (c) treatment of intact cells with hyaluronidase prior to extraction with digitonin resulted in a 3-fold increase in solubilized synthetase activity. Furthermore, gel filtration chromatography of the solubilized hyaluronidase-treated synthetase complex showed that it was smaller than the solubilized untreated synthetase complex, due to shorter nascent-bound hyaluronate. The solubilized synthetase was shown to be associated with hyaluronate in the form of a complex. Both hyaluronidase-treated and -untreated synthetase-hyaluronate complexes after solubilization were adsorbed by an affinity matrix using the hyaluronate binding domain of rat chondrosarcoma proteoglycan as ligand. This solubilized active enzyme preparation should allow the identification and characterization of the components of the hyaluronate-synthetase complex.

Animals↗

PubMed1988

Efficacy and pharmacokinetics of oral pirmenol, a new antiarrhythmic drug.

Pirmenol is a new orally effective antiarrhythmic agent. Reported are the results of oral administration of pirmenol to six patients (age 48.5 +/- 8.6 years, weight 83 +/- 15 kg) with stable ventricular extrasystoles (PVCs)--average ectopy rate 1040 +/- 630/hr (mean +/- SD). Patients received oral doses of placebo or 200 mg of pirmenol in a double-blind cross-over fashion followed by a single-blind rising-dose administration of 250 mg and 300 mg of pirmenol. The time period between doses was 48 hours. Pirmenol was rapidly absorbed (time to peak plasma levels 1 to 1.5 hours) and the mean maximum plasma concentrations were 1.8, 2.7 and 3.4 micrograms/mL with 200-mg, 250-mg and 300-mg doses, respectively. The elimination half-life was 9.3 +/- 3.0 hours and 31 +/- 14% of the dose was recovered in urine. The response criterion (80% suppression of PVCs of control for 8 hours) was met after the 300-mg dose in three patients. In three patients greater than 80% reduction occurred for up to 8 hours after the 200-mg dose. Pirmenol administration was not associated with any significant changes in blood pressure, heart rate, hepatic and renal function, PR interval or QRS duration. LV ejection fraction determined echocardiographically decreased from 63.0 +/- 6.9% predose to 59.7 +/- 5.0% about 2 hours after the 300-mg dose and QT interval increased by less than 10%. Two patients complained of transient bad taste sensation. Our results suggest that 250 mg to 300 mg of pirmenol, administered twice a day will suppress the PVCs effectively.

Administration, Oral↗

PubMedDate not supplied

Prostatic stromal sarcoma in a young adult: a case report.

Prostate stromal sarcoma is quite rare, comprising only 0.1-0.2% of all prostate cancers. Here, we report one case of prostate stromal sarcoma in a 38-year-old man. Initially, the patient suffered from lower urinary tract symptoms, and intravenous pyelography showed a larger filling defect in the bladder. Transrectal ultrasound showed a huge heterogenous mass between the bladder and rectum. Abdominal computed tomography revealed prostate tumor with local invasion. Radical cystoprostatectomy with ileal conduit was performed; pathology revealed high-grade prostate stromal sarcoma with invasion to the right seminal vesicle and urethra. This article describes the pathology and immunohistrochemical features of this case and briefly reviews the literature.

Adult↗

PubMedDate not supplied

Thrombelastographic patterns during cryotherapy for recurrent hepatocellular carcinoma.

A cirrhotic patient with recurrent hepatocellular carcinoma and thrombocytopenia undergoing cryotherapy showed: 1) transient hyperfibrinolysis shortly after platelet transfusion, and 2) evidence of activation of coagulation after freezing and thawing of tumor as measured on the thrombelastography. No anti-fibrinolytic treatment was required for the hyperfibrinolysis which subsided spontaneously in this patient. This case report highlights that: 1) in patients with chronic liver disease, platelet transfusion might potentially worsen rather than improve the hemostatic function by activation of fibrinolysis, and 2) activation of coagulation may underlie the perioperative coagulation changes seen in cryotherapy.

Carcinoma, Hepatocellular↗

PubMedDate not supplied

p16INK4 gene mutation and allelic loss of chromosome 9p21-22 in Taiwanese hepatocellular carcinoma.

BACKGROUND: The p16INK4 (MTS1/CDNK2A) gene, located on chromosome 9p21, is an inhibitor of cyclin-dependent kinase 4. Various data have shown that it is frequently inactivated in several types of cell lines and primary human cancers. MATERIALS AND METHODS: Thirty cases with hepatocellular carcinoma were studied for possible p16INK4 gene mutation in Taiwan. Homozygous deletion was determined using polymerase chain reaction (PCR). The p16INK4 gene mutation was first screened by single strand conformation polymorphism, then direct DNA sequencing was performed on the cases with mobility shifts. Deletion mapping of chromosome 9p21-22 was also carried out with two polymorphic microsatellite markers (D9S925 and D9S168) using PCR. RESULTS: One of the 30 cases had homozygous deletion at exon 3 of the p16INK4 gene. Another tumor had altered electrophoresed mobility in exon 2 with G to T transversion in the first nucleotide of codon 61 by direct sequencing causing a stop codon (GAG-->TAG). At the D9S925 and D9S168 loci, six out of 24 (25%) and three out of 19 (16%) informative cases showed loss of heterozygosity, respectively. CONCLUSION: Point mutation and homozygous deletion of the p16INK4 gene are present in a subset of hepatocellular carcinomas in Taiwan. The patterns of the p16INK4 gene alteration are, however, different from those from other regions. In addition, allelic loss on chromosome 9p21-22 is not an uncommon event in hepatocellular carcinomas. Therefore, the significance of chromosome 9p loss deserves to be extensively investigated.

Adult↗

PubMedDate not supplied

Coagulation and cytokine profile after major hepatobiliary surgery in Chinese patients.

BACKGROUND/AIMS: Hypercoagulability and increased circulating cytokine levels have been separately reported after surgical operations. We investigated whether the cytokine level and postoperative coagulation profile would change similarly in Chinese patients undergoing major hepatobiliary surgery. METHODOLOGY: Serial serum levels of IL-6, IL-1 beta and TNF-alpha were measured by colorimetric ELISA. Serial coagulation profile was measured by thrombelastography. Hemoglobin and white cell counts were also measured serially. RESULTS: Only mild hypercoagulability was found at the 12th and 144th hours, evidenced by shortening of r-time and k-time on thrombelastography (P < 0.05). IL-6 and IL-1 beta levels were significantly raised from the 12th hour (P < 0.01) while TNF-alpha level was unchanged. From the 3rd hour to the 48th hour, there was negative correlation between IL-6 levels and various thrombelastographic parameters such as coagulation index (r = -0.777, P < 0.001); k-time (r = 0.478, P < 0.05); maximum amplitude (r = -0.688, P < 0.01) and angle (r = -0.665, P < 0.01). CONCLUSIONS: We observed a much milder degree of hypercoagulability in Chinese patients after major hepatobiliary surgery as compared to those reported in other operations in non-Chinese patients. Unlike in sepsis where a close link between increased cytokine levels and hypercoagulability has been reported, increase in IL-6 was associated with less hypercoagulability in Chinese patients after major hepatobiliary surgery.

Adult↗