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Biomedical subjects

P K Ku

Publications and source records attributed to P K Ku.

At least 19 recordsLinked to original sources
PubMed2004

Dietary protein concentration affects plasma arteriovenous difference of amino acids across the porcine mammary gland.

The objective of this study was to determine whether the porcine mammary gland responds to increasing dietary CP concentration through changes in AA arteriovenous difference (a-v). Sixteen Landrace x Yorkshire lactating sows were provided ad libitum access to one of four isocaloric diets varying in CP concentration (7.8, 13.0, 18.2, and 23.5 %; as-fed basis). Litters were adjusted to 11 pigs within 48 h of birth. Sows were fitted with catheters in the carotid artery and main mammary vein on d 4. On d 10, 14, 18, and 22 of lactation, arterial and venous blood samples were obtained every 30 min over 6 h. Milk yield was estimated on d 11 and 21 using the D2O dilution technique. Final litter sizes on d 21 were 10.3, 11, 9.5, and 11 piglets for sows fed the 7.8, 13.0, 18.2, and 23.5% CP diets, respectively. Piglet ADG tended (P = 0.088) to increase with increasing dietary CP concentration and were 186, 221, 220, and 202 g for sows fed the 7.8, 13.0, 18.2, and 23.5% CP diet, respectively. Daily total milk yield on d 21 (kg milk/d) tended (P = 0.099) to increase, and average milk yield per nursed piglet (kg of milk-pig(-1)d(-1)) increased (P < 0.05) with increasing CP concentration and were, on a per-piglet basis, 0.95, 1.19, 1.14 and 1.13 kg of milk/d for the 7.8, 13.0, 18.2, and 23.5% CP diets, respectively. As dietary CP increased from 7.8 to 23.5%, isoleucine and leucine a-v increased linearly only (linear, P < 0.01); all other AA a-v increased, reached a maximum in sows fed 18.2% CP, and decreased thereafter in sows fed 23.5% CP (quadratic, from P = 0.10 to P < 0.05). Amino acid uptake by the entire udder and by each gland increased (linear, P < 0.05) with increasing dietary CP. Arteriovenous differences response to increasing day of lactation varied among AA, from no change for histidine, isoleucine, lysine, methionine, tryptophan, and valine, to a linear trend increase for arginine (P = 0.055), leucine (P = 0.064), phenylalanine (P = 0.101), and threonine (P = 0.057). In summary, for the majority of AA, a-v increased with increasing dietary CP concentration from 7.8 to 18.2%, but decreased when CP concentration exceeded 18.2%. In contrast, mammary AA uptake, piglet ADG and milk yield per pig increased linearly with increasing dietary CP, suggesting a coordinated regulation between AA delivery and transport to meet the demand for milk yield.

Amino Acids↗
PubMed2003

Nitrogen balance and ileal amino acid digestibility in growing pigs fed diets reduced in protein concentration.

Two studies were conducted to assess the effect of dietary protein reduction on N utilization, N excretion, and AA digestibility in growing pigs. The objective was to determine whether pigs fed diets with a reduced CP concentration could maintain the same N retention as pigs fed an adequate diet. The second objective was to test whether reducing dietary CP concentration decreases AA digestibility. In each study, six barrows were allotted to one of six dietary treatments in a Latin square design. Treatments consisted of four corn-soybean meal-based diets containing 15, 12, 9, and 6% CP, a casein-based diet containing 15% CP, and a protein-free diet. Crystalline AA were included in the 12, 9, and 6% CP diets. The indispensable:dispensable AA ratio was maintained at 45:55 with the addition of L-glutamic acid to the 9 and 6% CP diets. The casein-based and protein-free diets were used to determine endogenous total tract N and ileal AA losses. In the first study, total N losses and N absorbed decreased linearly (P < 0.001) as dietary CP concentration decreased from 15 to 6%. Both a linear (P < 0.001) and a quadratic (P < 0.05) decrease in N retention were found with decreasing dietary CP concentration. Nitrogen retained as a percentage of intake and absorbed increased (P < 0.001) as dietary CP concentration was reduced from 15 to 6%. In the second study, six barrows were surgically fitted with a T-cannula at the terminal ileum to determine ileal AA digestibility. For all dispensable and most indispensable AA, apparent and standardized ileal digestibility increased linearly (P 0.01, and for arginine, P < 0.05) as dietary CP concentration decreased. These results indicate that dietary CP concentration can be decreased from 15 to 12% with crystalline AA supplementation to meet an ideal AA profile without adversely affecting N retention, and that decreasing dietary CP concentration from 15 to 6% increases both dispensable and indispensable AA ileal digestibility.

Amino Acids↗
PubMed2002

Equine endurance exercise alters serum branched-chain amino acid and alanine concentrations.

Six 2-year-old Arabian horses were used to determine whether 60 km prolonged endurance exercise (approximately 4 h) alters amino acid concentrations in serum and muscle, and the time required for serum amino acid concentrations to return to basal resting values. Blood and muscle samples were collected throughout exercise and during a 3 day recovery period. Isoleucine concentration in muscle tended to increase and leucine and valine did not change due to exercise. Serum alanine concentrations did not increase immediately after exercise, but increased at 24, 48 and 72 h postexercise. Serum isoleucine, leucine, and valine concentrations decreased after exercise and time required to reach pre-exercising concentrations was 48 h. In conclusion, endurance exercise in the horse decreases serum isoleucine, leucine, and valine concentrations, and increases serum alanine concentration. The decrease in serum branched-chain amino acid concentrations did not correspond to a measurable increase in total muscle branched-chain amino acid concentrations.

Alanine↗
PubMed2001

Incidence of carotid stenosis in nasopharyngeal carcinoma patients after radiotherapy.

BACKGROUND: Radiation-induced carotid stenosis in patients with head and neck tumors can cause significant mortality and morbidity. This study examined the incidence of stenosis in the extracranial carotid arteries of nasopharyngeal carcinoma patients after radiotherapy. METHODS: The extracranial carotid arteries of 71 (53 male and 18 female; mean age of 53.6 years) postradiation patients with nasopharyngeal carcinoma were examined with color Doppler ultrasound. The distribution of the arterial stenosis and the degree of stenosis were documented. The results were compared with the control group, which comprised 51 newly diagnosed nasopharyngeal carcinoma patients (35 male and 16 female, mean age of 48.8 years) before radiotherapy. Incidences of risk factors for arterial stenosis such as hypertension, smoking, and hypercholesterolemia also were studied in these two groups. RESULTS: There was no significant difference in the incidence of risk factors between the two groups. Arterial stenosis was, however, more common in the postradiation group than the preradiation group (56 of 71 vs. 11 of 51). The common/internal carotid arteries (CCA/ICA) were most commonly involved (55 of 71 vs. 11 of 51; P < 0.01), followed by the external carotid artery (ECA) (32 of 71 vs. 1 of 51; P < 0.01) and vertebral artery (VA; 5 of 71 vs. 0; P = 0.069). Significant stenosis (> 50% reduction of luminal diameter) was only found in the postradiation group (21 of 71 in CCA/ICA, 11 of 71 in ECA, 4 of 71 in VA). CONCLUSIONS: This study showed that radiation could cause significant carotid stenosis. Ultrasound examinations for these patients therefore are necessary for early detection and possible intervention of this late radiation-induced complication.

Adult↗
PubMed2001

Nasopharyngectomy for recurrent nasopharyngeal carcinoma: an innovative transnasal approach through a mid-face deglove incision with stereotactic navigation guidance.

Traditional approaches to nasopharyngectomy for the treatment of recurrent nasopharyngeal carcinoma carry considerable complications. This paper presents an innovative transnasal approach with stereotactic navigation guidance through a mid-face deglove incision which has been done for 15 patients with minimal morbidity. All patients had resumed their oral diet within a week, and were discharged within 10 days. The intraoral wound had healed within a week. The only complications were a mild degree of saddling of the nasal dorsum in one patient and temporary facial numbness that resolved within six weeks in three. Tumour had been resected with clear margins in 12/15, in the other three being stuck to the carotid artery.

Adult↗
PubMed2001

The 'double bag': a device for protection against blood spray in the management of epistaxis.

Nasal bleeding is one of the commonest emergencies that place medical staff at risk of blood contamination during management. A sizeable proportion of incidents have been reported where blood splashes in the facial area caused such contamination, and the exposed conjunctivae are potential sites for transmission of human immunodeficiency viruses (HIV). We present a simple self-made device named the 'Double Bag', which is highly effective in preventing blood spraying during the management of epistaxis. It was designed to be used while treating epistaxis or removing nasal packing after surgery, when transient bleeding is expected.

Blood-Borne Pathogens↗
PubMed2000

Foley catheter action in the nasopharynx: a cadaveric study.

OBJECTIVES: To determine the action of the Foley catheter in the posterior nasal cavity in relation to balloon volume, and to deduce its implications in the treatment of posterior epistaxis. DESIGN: Human cadaveric study. MATERIALS: Twenty nasal fossae of 10 adult cadavers. INTERVENTIONS: A Foley catheter (size 14) was inserted into the nasopharynx via each nostril. The catheter balloon was inflated to its recommended maximum volume with 15 mL of water. Firm traction was applied to the catheter. Colored liquid was instilled into the ipsilateral aspect of the nasal cavity, and liquid leakage into the contralateral side was monitored using a nasoendoscope. The balloon was reduced in volume by 1-mL steps, and the same fluid infusion and documentation procedures were performed for each reduced volume until the balloon slipped out of the nose. The procedure was repeated in the opposite nostril. MAIN OUTCOME MEASURES: Successful choanal sealing and anterior balloon shift into the nasal fossa in relation to the balloon size. RESULTS: The Foley catheter balloon sealed the choana without any leakage of infused liquid into the contralateral side at appropriate inflation volumes in 17 (85%) of 20 nasal fossae. Complete sealing between volumes of 12 and 15 mL was achieved in 13 fossae (65%), between 11 and 15 mL in 10 nasal fossae (50%), and between 5 and 15 mL in 3 nasal fossae (15%). Failure to seal at any volume occurred in 3 nasal fossae (15%). Bimodal seal (ie, complete seal at high [15 mL] and low volumes [4-7 mL], but leakage in intermediate volumes) occurred in 3 nasal fossae (15%). The balloon remained in the nasopharynx under traction and did not slip past the choanal rim to encroach on the middle and inferior turbinates until the balloon volume was reduced to between 4 and 7 mL. The balloon slid out of the nose at a volume of 5 mL or less. The inflation volumes ranging from 8 to 12 mL were statistically more effective in sealing the choana than lower volumes (4-7 mL) (P<.002, chi(2) test). CONCLUSIONS: At different inflation volumes, the Foley catheter balloon acts primarily (1) as a platform for an anterior gauze pack (at 4-15 mL); (2) as an effective seal of the choana (at 8-15 mL usually and at 4-7 mL occasionally); and (3) as a compressor of the region behind the middle and inferior turbinates (at 4-7 mL), provided that the balloon under traction does not slip out of the nose.

Adult↗
PubMed2000

Nasopharyngectomy in the treatment of recurrent nasopharyngeal carcinoma: a twelve-year experience.

BACKGROUND: The incidence of recurrent nasopharyngeal carcinoma (NPC) after primary radiotherapy is considerable. The result of re-irradiation to the recurrent tumor is not satisfactory. METHODS: Thirty-one patients who received nasopharyngectomy for treatment of their recurrent nasopharyngeal carcinoma (NPC) (rT1 to rT3) at the Prince of Wales Hospital during the period 1986 to 1997 were reviewed retrospectively. Eleven patients had nasopharyngectomy performed by the transoropalatal approach, 9 patients by the maxillary swing approach, and 11 patients by the mandibular approach. RESULTS: Most recurrences (29 of 31) were rT1 and rT2 tumors. No hospital mortality occurred. The common complications of nasopharyngectomy were palatal defect (17 of 31), trismus (15 of 31), otitis media with effusion (20 of 31), dysphagia (12 of 31), and nasal regurgitation (8 of 31). Nine surgical specimens had microscopic invasion of the resection margins. The 5-year actuarial overall survival, actuarial disease-free survival, and tumor control were 47%, 42%, and 43%, respectively. The administration of postoperative radiotherapy significantly enhanced survival and tumor control after nasopharyngectomy. CONCLUSIONS: Nasopharyngectomy supplemented by postoperative radiotherapy achieved significant survival and tumor control with acceptable complications in selected recurrent NPC. It appears to be a better salvage treatment than re-irradiation alone for selected recurrent NPC.

Adenocarcinoma↗
PubMed2000

High chromium yeast supplementation improves glucose tolerance in pigs by decreasing hepatic extraction of insulin.

Twenty Landrace x Yorkshire cross pigs (body wt, 47.9+/-2.9 kg) were used to evaluate effects of dietary high chromium (Cr) yeast supplementation on plasma kinetics of glucose, insulin and C-peptide. Pigs were provided free access to either a control diet (C) containing 204 microg Cr/kg or a diet supplemented with an additional 200 microg Cr/kg as high Cr yeast (CR) for between 23 and 30 d. After overnight food deprivation, dextrose (500 g/L) was infused through a jugular vein catheter at a dose of 0.5 g glucose/kg body weight with an infusion rate of 10 g glucose/min within 6 min. High Cr yeast supplementation did not affect body weight gain or food intake. There were no differences in fasting plasma concentrations of either glucose or C-peptide, although basal plasma concentration of insulin tended to be higher in pigs fed CR (P<0.10). Plasma glucose concentrations were lower (P<0.01) at postinfusion times 5, 10, 15 and 20 min in pigs fed CR. Plasma insulin concentrations in pigs fed CR were higher (P<0.05) at 2 and 0 min before the completion of dextrose infusion. However, the increase in plasma insulin concentrations was not accompanied by a comparable elevation in plasma C-peptide concentrations. The 30-min (postinfusion) area of plasma glucose concentrations tended to be lower (P<0.10) in pigs fed CR, but there were no differences in 30-min areas of either plasma insulin or plasma C-peptide concentrations between treatments. Plasma clearance rates of glucose, insulin and C-peptide were higher and their half-lives shorter (P<0.05) in pigs fed CR. In conclusion, dietary high Cr yeast supplementation improved glucose tolerance, possibly through a decrease in hepatic extraction of insulin.

Animals↗
PubMed2000

Efficacy of ondansetron for prevention of postoperative nausea and vomiting after outpatient ear surgery under local anesthesia.

OBJECTIVE: To assess the efficacy and safety of intravenous ondansetron (4 mg) for the prevention of nausea and vomiting after middle ear surgery under local anesthesia. SETTING: The study was conducted by Division of Otorhinolaryngology in Prince of Wales Hospital, which is a tertiary referral center and teaching hospital for The Chinese University of Hong Kong. STUDY DESIGN: A double-blind randomized controlled trial. PATIENTS: Fifty-eight Chinese patients undergoing tympanoplasty under local anesthesia from July 1995 to June 1997 were recruited. The mean age of patients was 42.8 years (range 18-71 years). INTERVENTION: Patients were randomly allocated to receive a single dose of intravenous ondansetron (4 mg) (n = 29) or placebo (n = 29) immediately before surgery. MAIN OUTCOME MEASURES: Patients were assessed for severity and frequency of postoperative nausea and vomiting at the 1st, 2nd, 4th, 8th, and 24th hours after middle ear surgery. RESULTS: Female patients showed a higher prevalence of postoperative nausea and vomiting. Twenty-eight percent of the patients experienced postoperative nausea, of whom 14% also experienced vomiting. Although the ondansetron group demonstrated a lower prevalence of postoperative nausea and vomiting (PONV) (24% nausea and 10% vomiting) than the placebo group (31% nausea and 17% vomiting), significant reduction in postoperative vomiting only occurred in the first postoperative hour (p = 0.038). No complications or adverse side effects were found to be associated with the use of ondansetron. CONCLUSIONS: Single-dose ondansetron (4 mg) given intravenously preoperatively significantly reduces postoperative vomiting in patients after tympanoplasty under local anesthesia and causes no adverse effects.

Adolescent↗
PubMed2000

Osteoradionecrosis of the temporal bone in nasopharyngeal carcinoma after radiotherapy: a case report.

Osteoradionecrosis of the temporal bone after external-beam radiotherapy for nasopharyngeal carcinoma is not uncommon following a long posttreatment interval. We describe the case of a man who had experienced this complication 13 years after he had undergone such radiotherapy. His condition resolved after removal of dead bone from the external auditory canal, followed by antibiotic therapy and periodic aural toileting.

Aged↗
PubMed2000

Screening for otitis media with effusion to measure its prevalence in Chinese children in Hong Kong.

In an attempt to gain a better understanding of the prevalence of otitis media with effusion (OME) in the Hong Kong community, and to compare the characteristics of the disease here with OME as it is described in the Western literature, we screened more than 6,000 6- and 7-year-old children with both clinical and audiologic examinations. The initial positive screening rate was 5.3%. Upon further evaluation, we determined that the overall prevalence of persistent OME was 2.2%. We found that the disease pattern and natural history of persistent OME in Hong Kong children are similar to those reported in the Western literature.

Acoustic Impedance Tests↗
PubMed2000

Middle ear effusions after radiotherapy: correlation with pre-radiotherapy nasopharyngeal tumor patterns.

OBJECTIVE: The purpose of this study was to assess whether pretreatment tumor patterns of nasopharyngeal carcinoma (NPC) can predict the status of the middle ear after radiation treatment. MATERIALS AND METHODS: Pretreatment and follow-up magnetic resonance imaging (MRI) was performed in 32 patients (64 ears) who had radiation therapy for NPC. For the purpose of analysis, the ears were placed into their pre-radiation therapy tumor pattern groups and the presence of middle ear effusion (MEE) with regard to eustachian tube (ET) invasion or displacement was identified. RESULTS: MEEs were present in 31 (48.4%) ears after radiation therapy. All of the MEEs that resolved were in the preradiation therapy groups where tumor invasion of the eustachian tube was present irrespective of the amount of ET displacement. There was, however, no significant difference for resolved MEEs between ears with ET invasion or displacement (p = 0.32 and p = 0.71, respectively, Fisher's exact test). The MEEs occurred with significantly greater frequency in ears with minor ET displacement than in those with major ET displacement (p = 0.013, Fisher's exact test) as well as in previously normal ears compared with other groups (p = 0.008, Mann-Whitney U test). CONCLUSION: A pre-radiation therapy NPC tumor pattern was not found that clearly predicted the outcome of MEE after radiation treatment. The findings, however, suggest that approximately one third of MEEs in patients with invasion of ET or paratubal structures, irrespective of the amount of ET displacement, resolve after therapy. The MEEs that were present in ears with ET displacement and no invasion did not resolve despite reversal of the displacement after treatment, which suggests that ET position plays a less important role than invasion in the resolution of MEE. It is, however, difficult to be certain, because ears with invasion were invariably associated with ET displacement, and the contribution of radiation therapy to the development of MEE further complicates the issue.

Adult↗
PubMed1999

Nasal manifestation of extranodal Rosai-Dorfman disease--diagnosis and management.

Two cases of Rosai-Dorfman disease with polypoid nasal infiltration mimicking nasal tuberculosis and malignant lymphoma are reported. This rare benign disease was first described by Rosai and Dorfman in 1969 and is characterized by histiocytic proliferation. It is seldom considered in the differential diagnosis of granulomatous diseases due to its rarity and histological similarity to other diseases. Extranodal manifestations of this disease are uncommon. Although no specific treatment can guarantee a sustained remission of this disease, surgery for loco-regional lesions can result in long-term symptomatic control and restoration of function. Both patients underwent endoscopic resection of the nasal polypoid lesions and have subsequently been free of recurrence. Loco-regional infiltration of the nasal cavity by Rosai-Dorfman disease is effectively managed by endoscopic resection.

Adult↗