PubMed Health⌕ Search

Biomedical subjects

K Kan

Publications and source records attributed to K Kan.

At least 19 recordsLinked to original sources
PubMed2002

Teaching paediatric dentistry by multimedia: a three-year report.

Clinical cases can now be simulated utilising multimedia and used to teach case management to dental students. The modules developed should provide intellectual stimulation, user-interaction and immediate feedback, in addition to being intuitively navigated and user-helpful. Five paediatric dental case modules (early childhood caries, anterior trauma, anterior coronal fragment, anterior crossbite and dentigerous cyst) were created, installed in a multimedia presentation tool, PathFinder (from Westmead Hospital Dental Clinical School, New South Wales, Australia), and used to teach three classes of fourth year dental students at The University of Melbourne. Questionnaires, focus groups and a review were conducted by an external educational expert. Students responded anonymously to general learning questions and case specific questions using a five-point Likert scale (strongly agree to strongly disagree). Student responses indicated they were very enthusiastic about learning via multimedia, although a few students disliked this educational approach. Focus groups and external review indicated that the modules were navigated readily and were suitably interactive.

Case Management↗
PubMed2001

Effect of Antioxidants on Radical-initiated Peroxidation of Retinal Homogenate.

Purpose: To compare the effect of antioxidants on radical-initiated peroxidation of retinal homogenate.Methods: Lipid peroxides in bovine retinal homogenate were induced by 5 mM FeNO(3) (Fe), 25 mM 2, 2'-azobis(2, 4'-dimethylvaleronitrile) (lipid-soluble, AMVN) or 50 mM 2, 2'-azobis (2-amidinoprpane) dihydrochloride (water-soluble, AAPH) and the preventive effects of antioxidants were measured. Phosphatidylcholine hydroperoxide (PC-OOH) was analyzed with high performance liquid chromatography (HPLC) as the endpoint biomarker.Results and Conclusion: Troglitazone, an oral hypoglycemic agent, inhibited PC-OOH production by Fe and AMVN. Therefore, it may be effective for protecting against oxidative stress on the inner surface plasma membranes and subcellular organelle. Quercetin has radical scavenging effects on both sides of the membrane, because it prevents PC-OOH production by AMVN or AAPH. These results demonstrate the usefulness of an in vitro screening test that can accurately and rapidly determine the capacity of an antioxidant against lipid peroxidation or oxidative stress. (Jpn Ophthalmol Soc 104:466-70, 2000)

Journal Article↗
PubMed2001

[The effectiveness of ozonated water for hand washing before surgery].

Using an ozonated water-dispensing machine for sterilization of hands (Mediaqua MA-III; Core Medical Co., Ltd, Tokyo, Japan), we investigated the effectiveness of ozonated water as a disinfectant for hand washing before surgery. The effectiveness of this new hand-washing method, using 4 ppm of ozonated water, which is expected to have a short-term bactericidal effect, and 0.2% benzalkonium chloride/83% ethanol solution (Welpas), which is expected to have a long-term bactericidal effect, was compared with that of the conventional hand-washing method (Fürbringer's method using a scrubbing agent containing povidone-iodine). The results showed no significant differences in the numbers of live bacteria and exponential reduction rates in live bacteria. Thus, this new method for hand washing using ozonated water is an effective method for sterilization of the hands before surgery.

Benzalkonium Compounds↗
PubMed2000

Novel design of nonpeptide AVP V(2) receptor agonists: structural requirements for an agonist having 1-(4-aminobenzoyl)-2,3,4, 5-tetrahydro-1H-1-benzazepine as a template.

The discovery of a series of nonpeptide arginine vasopressin V(2) receptor agonists is described. After identifying the aniline derivative 8 as our lead compound from the metabolites of compound 7 that showed antidiuretic activity by po administration to Brattleboro rats, improvements in the in vitro potency involving evaluations of the structural requirements for agonist action and optimizing the structure of the benzoyl moiety have been intensively undertaken. These studies led to compounds 16g, 19a, and 23b,h,i that show potent agonist activity for the V(2) receptor.

Administration, Oral↗
PubMed2000

Age, strain, and semi-chronic hydergine treatment effects on motor activity and neuronal nucleic acid-protein metabolism in male mice.

This study was designed to examine the effects of Hydergine (DHET), co-dergocrine mesylate, treatment on motor activity and neuronal nucleoprotein metabolism in several motor areas of the aging rodent brain, specifically the caudate-putamen (CP), the substantia nigra (SN), and the cerebral cortex layer V (CX). Three age groups of two different strains of mice were used which represented two different aging rates: DBA/2 male mice (short lived) and C57BL/6 male mice (long lived). A representative sample of each age group was injected (IP) daily with a single dose of either DHET (1 mg/kg) or vehicle (0.9% saline) solution for one month. Total spontaneous motor activity was measured using a File apparatus to assess the functional ability of the selected brain areas. Histochemical parameters measured included the relative RNA and protein contents from a homogeneous population of neurons within each nuclei. The RNA and protein contents were assessed with a scanning microdensitometer using azure B and Coomassie staining protocols, respectively. The results of this study provide evidence that DHET does have significant effects on neuronal functioning in the motor compartments studied at the behavioral as well as the histochemical level for DBA/2 male mice. The C57BL/6 strain showed parallel, but less significant, changes in the histochemical parameters and no statistical differences in motor activity. In addition, DHET treatment produced no sign of neurotoxicity within any of the brain nuclei in either strain.

Aging↗
PubMed2000

Characterization of a novel nonpeptide vasopressin V(2)-agonist, OPC-51803, in cells transfected human vasopressin receptor subtypes.

We discovered the first nonpeptide arginine-vasopressin (AVP) V(2)-receptor agonist, OPC-51803. Pharmacological properties of OPC-51803 were elucidated using HeLa cells expressing human AVP receptor subtypes (V(2), V(1a) and V(1b)) and compared with those of 1-desamino-8-D-arginine vasopressin (dDAVP), a peptide V(2)-receptor agonist. OPC-51803 and dDAVP displaced [(3)H]-AVP binding to human V(2)- and V(1a)-receptors with K(i) values of 91.9+/-10.8 nM (n = 6) and 3.12+/-0.38 nM (n = 6) for V(2)-receptors, and 819+/-39 nM (n = 6) and 41.5+/-9.9 nM (n = 6) for V(1a)-receptors, indicating that OPC-51803 was about nine times more selective for V(2)-receptors, similar to the selectivity of dDAVP. OPC-51803 scarcely displaced [(3)H]-AVP binding to human V(1b)-receptors even at 10(-4) M, while dDAVP showed potent affinity to human V(1b)-receptors with the K(i) value of 13.7+/-3.2 nM (n = 4). OPC-51803 concentration-dependently increased cyclic adenosine 3', 5'-monophosphate (cyclic AMP) production in HeLa cells expressing human V(2)-receptors with an EC(50) value of 189+/-14 nM (n = 6). The concentration-response curve for cyclic AMP production induced by OPC-51803 was shifted to the right in the presence of a V(2)-antagonist, OPC-31260. At 10(-5) M, OPC-51803 did not increase the intracellular Ca(2+) concentration ([Ca(2+)](i)) in HeLa cells expressing human V(1a)-receptors. On the other hand, dDAVP increased [Ca(2+)](i) in HeLa cells expressing human V(1a)- and V(1b)-receptors in a concentration-dependent fashion. From these results, OPC-51803 has been confirmed to be the first nonpeptide agonist for human AVP V(2)-receptors without agonistic activities for V(1a)- and V(1b)-receptors. OPC-51803 may be useful for the treatment of AVP-deficient pathophysiological states and as a tool for AVP researches.

Arginine Vasopressin↗
PubMed2000

[Effect of antioxidants on radical-initiated peroxidation of retinal homogenate].

PURPOSE: To compare the effect of antioxidants on radical-initiated peroxidation of retinal homogenate. METHODS: Lipid peroxides in bovine retinal homogenate were induced by 5 mM FeNO3 (Fe), 25 mM 2, 2'-azobis(2,4'-dimethylvaleronitrile) (lipid-soluble, AMVN) or 50 mM 2,2'-azobis (2-amidinoprpane) dihydrochloride (water-soluble, AAPH) and the preventive effects of antioxidants were measured. Phosphatidylcholine hydroperoxide (PC-OOH) was analyzed with high performance liquid chromatography (HPLC) as the endpoint biomarker. RESULTS AND CONCLUSION: Troglitazone, an oral hypoglycemic agent, inhibited PC-OOH production by Fe and AMVN. Therefore, it may be effective for protecting against oxidative stress on the inner surface plasma membranes and subcellular organelle. Quercetin has radical scavenging effects on both sides of the membrane, because it prevents PC-OOH production by AMVN or AAPH. These results demonstrate the usefulness of an in vitro screening test that can accurately and rapidly determine the capacity of an antioxidant against lipid peroxidation or oxidative stress.

Animals↗
PubMed1999

Synthesis of oligonucleotides containing a new azobenzene fragment with efficient photoisomerizability.

The azobenzene derivatives possessing substituents of ROCH2CH2O- and-CH2CH2OR' or -CONHCH2CH2OR' at p,p'-positions, where R and R' are 4,4'-dimethoxytrityl and 2-cyanoethyl-N,N'-diisopropylphophoramidite, have been synthesized for linking two oligonucelotide segments. It has been found that the azobenzene linkers efficiently undergo trans-cis isomerization by exposing to UV light. The conversion efficiency showed slight dependence on structure or conformation of oligonucleotides attached to the azobenzene chromophore. The cis-form of the azobenzene in oligonucleotides was sufficiently stable at low temperature under dark. The present findings would open the way for light switch of nucleic acid structures.

Azo Compounds↗
PubMed1999

[Pharmacological study of weekly docetaxel in patients with metastatic breast cancer].

A pharmacological comparison of weekly administrations of docetaxel (TXT) and standard/conventional TXT was carried out among patients with metastatic breast cancer. Fifteen patients were enrolled in this study of weekly TXT (TXT: 40 mg/body/week x 3 with 1 week interruptions in 10 patients) and standard TXT (TXT: 60 mg/m2/3 weeks in 5 patients). The median dose intensity (DI) of weekly TXT (20.63 mg/m2/week) was similar to that of standard TXT, and the median relative dose intensity (RDI) of weekly TXT was 0.98. The median area under the plasma concentration-time curve (AUC) of weekly TXT (1.20 micrograms.h/ml) was smaller than that of standard TXT (1.87 micrograms.h/ml). Therefore, there were remarkable decreases in both median percent of decrease in neutrophil counts and grade 3, 4 neutropenia with weekly TXT. These pharmacological data show that weekly TXT is a well-tolerated and feasible schedule for the treatment of metastatic breast cancer.

Adult↗
PubMed1999

[The efficacy and limitation of hepatic arterial infusion chemotherapy for colorectal liver metastases].

We investigated the efficacy and limitation of hepatic arterial infusion (HAI) chemotherapy for colorectal liver metastases. In terms of prophylactic HAI following curative resection of liver, the 5-year disease-free survival of HAI group (12 g of 5-FU administered in 6 weeks) was 66.7%, whereas that of randomly selected control group was 20.0%. The difference was statistically significant (p = 0.045). Recurrent disease was confirmed in three cases of HAI group (one in liver) and in 8 patients of the control group (6 in liver). However, the overall survival was not significantly different between the groups. Thus, the short-term HAI of 5-FU is effective in decreasing the recurrence of disease. As for the treatment of unresectable liver metastases, some patients received HAI of 5-FU (1,000-1,500 mg/w) showed prolonged survival with partial remission of the disease. However, the 1-, 2-, and 3-year cumulative survival of HAI group (n = 27) was 69.3, 34.1 and 11.4%, respectively, against 61.3, 22.6 and 9.4%, respectively, in the transarterial embolization (TAE) group (n = 31). Therefore it is important to estimate the effect in the early phase of HAI, and aggressively continue the treatment in selected patients for whom it is suitable.

Administration, Oral↗
PubMed1998

Radon-222 and gamma ray levels associated with the collection, processing, transmission, and utilization of natural gas.

The natural gas industry in British Columbia was investigated for exposure to radioactive contaminants such as radon-222 and lead-210. Radon activity associated with the gathering system ranged from 7-921 Bq/m3. The pipelines to the processing facility contained sludge that had a mean lead-210 activity of 0.494 Bq/g (0.379 standard deviation [SD]) and a mean radium-226 activity of 0.417 (0.398 SD). Within the processing facility the highest levels of radon were associated with propane production streams, and activities as high as 4958 Bq/m3 were found. Equipment handling these streams was also found to have a buildup of scale with lead-210, radium-224, and radium-226 activity. The transmission of salable gas to the consumer indicated a decrease in radon activity that was slightly lower than the estimated radon activity based on the half-life of radon, the distance from the production facility, and the speed of gas transmission. The risk of radon exposure to the worker was deemed well below the guidelines and would be controlled more than adequately by means of the occupational standards for the natural gas components. Gamma ray exposure was also well below the occupational standards. Radon exposure to the consumer was virtually nonexistent in the Vancouver region from both natural gas and propane. Although this might not be the case for consumers of propane closer to the production facilities, its contribution is likely to be minimal.

British Columbia↗
PubMed1998

[A CR case of amylase-producing tumor treated by hyperthermochemotherapy].

A 64-year-old female who was diagnosed with an amylase-producing tumor of unknown origin was treated by hyperthermochemotherapy. The patient was admitted with a complaint of abdominal fullness due to ascites. Laboratory examination showed high levels of serum amylase and tumor markers, including CA15-3, CA 125 and CA 72-4. Laparotomy showed peritoneal dissemination with histological findings of adenocarcinoma of unknown origin. After laparotomy, she was given hyperthermia combined with chemotherapy using carboplatin (CBDCA), mitomycin C (MMC) and doxifluridine (5'-DFUR). Hyperthermia (13.56 MHz radiofrequency for 40-50 min) was performed a total of six times within one and a half months. The total doses of CBDCA and MMC were 450 mg and 24 mg, respectively, and 600 mg of 5'-DFUR was orally administered every day. By these combined treatments, ascites disappeared and serum levels of amylase and all tumor markers were decreased and normalized. MRI and echo examination also showed complete disappearance of peritoneal metastasis. Two and a half years after the treatment, the patient is alive without any evidence of recurrence, which suggests that this combined therapy is one of the useful modalities for peritoneal dissemination as well as an inoperable tumor itself.

Adenocarcinoma↗
PubMed1998

[Intra-arterial chemotherapy to improve quality of life in cases of unresectable advanced or recurrent breast cancer].

We performed repetitive intra-arterial infusion chemotherapy (I.A.) with epirubicin in order to improve the quality of life (QOL) in 3 cases with locally advanced or recurrent breast cancer which were diagnosed as surgically unresectable and seemed uncontrollable by outpatient systemic chemotherapy. The patients were admitted to our hospital for chest wall invasion, lymph node metastasis, bleeding, pain, or edema in upper extremity. Therapeutic effects included 1 case of CR and 2 cases of PR in the primary site, and similar effects were obtained in metastasized lymph nodes. We could perform mastectomy in both of the 2 cases with locally advanced cancer after I.A., Although leukocytopenia, which was the dose limiting factor in this regimen, was observed in all 3 cases, it was Grade 2 or 3 and recovered by G-CSF. With regard to their QOL, symptoms which had driven them to inpatient treatment remarkably improved in all of the cases. Thus, after 2 series of I.A. they could receive maintenance systemic chemotherapy as outpatients. Our findings showed that the I.A. as a local control treatment in patients with unresectable advanced or recurrent breast cancer is useful for the improvement of their QOL.

Antibiotics, Antineoplastic↗
PubMed1998

[Long-term survival in a case of multiple liver metastasis from postoperative gastric cancer effectively treated by hepatic intraarterial infusion chemotherapy using MMC and pirarubicin].

We experienced a case of multiple liver metastasis from postoperative gastric cancer who showed long-term survival with hepatic arterial infusion chemotherapy (HAI) of MMC and pirarubicin. A catheter was inserted into the hepatic artery, and 4 mg of MMC and 20 mg of pirarubicin were administered through an implantable port catheter every two to four weeks. The total dose of MMC and pirarubicin by the time of this report was 164 mg and 820 mg, respectively. The follow-up CT scan 2 months after the beginning of HAI showed a decrement of the liver tumors. The decrease rate at 12 and 17 months was 50% and 70%, respectively, which was diagnosed as partial response (PR). The therapeutic effect at 49 months is still PR without any sign of tumor enlargement of extra hepatic lesion.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1998

[Effects of intravenous infusion of 5-FU and intraperitoneal injection of low-dose CDDP on 3 cases with ascites owing to peritonitis carcinomatosa of postoperative gastric carcinoma and debility].

We examined the effects of intravenous infusion of 5-FU and intraperitoneal injection of low-dose CDDP on 3 cases with ascites owing to peritonitis carcinomatosa of postoperative gastric carcinoma and debility. Intravenous infusion of 5-FU (250-1,000 mg/body) and intraperitoneal injection of CDDP (20-25 mg/body) carried out for 2-5 days. As a result, QOL of 3 cases was fairly improved. The PS (Performance Status) of 2 cases improved from Grade 4 to 2, and another one improved from Grade 4 to 3. Adverse effects of Grade 1 according to the WHO criteria were observed in 1 case (leukocytopenia and diarrhea). This palliative chemotherapy method appeared to be safe and effective for ascites due to peritonitis carcinomatosa of postoperative gastric carcinoma and debility.

Aged↗
PubMed1998

[A case of locally advanced breast cancer successfully treated with intra-arterial infusion chemotherapy of high-dose epirubicin].

A case of locally advanced breast cancer was treated with intra-arterial infusion chemotherapy using high-dose epirubicin. The 1st and 2nd cycle consisted of 210 mg (day 1, 4, 7) and 150 mg (day 1, 4, 7), respectively. After completion of 2 cycles of the regimen, remarkable loco-regional control and improved QOL were obtained. Leucopenia (nadir; 1,000/mm3) was the dose limiting factor, but well-tolerated with supportive therapy. The patient underwent salvage surgery and maintenance intra-venous chemotherapy (epirubicin; 30 mg/3 weeks). At this writing, the patient is enjoying favorable QOL. These findings suggested that this modality was effective for cases with exctensive loco-regional involvement.

Antibiotics, Antineoplastic↗
PubMed1997

Solitary median maxillary central incisor, short stature, choanal atresia/midnasal stenosis (SMMCI) syndrome.

This article describes a series of 21 consecutive cases, each involving a solitary median maxillary central incisor; the patients were seen in the Department of Dentistry or the Victorian Clinical Genetics Unit, Murdoch Institute, at the Royal Children's Hospital, Melbourne, from 1966 to 1997. The spectrum of anomalies and associated features present in these cases--solitary median maxillary central incisor, choanal atresia, and holoprosencephaly--is described, and the literature related to the features, including genetic studies in these conditions, is reviewed. We relate our findings in these cases to current knowledge of developmental embryology. It is hoped that the findings, together with our interpretation of them, will help to clarify understanding of solitary median maxillary central incisor syndrome. This syndrome was previously considered a simple midline defect of the dental lamina, but it is now recognized as a possible predictor of holoprosencephalies of varying degrees in the proband, in members of the proband's family, and in the family's descendants.

Body Height↗