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Biomedical subjects

B Mak

Publications and source records attributed to B Mak.

14 recordsLinked to original sources
PubMed2005

Utility of the Health Belief Model in predicting compliance of screening in patients with chronic hepatitis B.

BACKGROUND: Regular surveillance is recommended for patients with chronic hepatitis B, to select candidates for anti-viral therapy and detect early complications. However, factors that determine compliance are not well studied. AIM: To determine the utility of the Health Belief Model in explaining non-compliance, among a group of chronic hepatitis B patients for screening. METHODS: A total of 192 chronic hepatitis B patients who responded to advertisement for free screening took part in a telephonic interview study. Subjects were asked about the five constructs of the Health Belief Model, and factors associated with recent screening were analysed. RESULTS: The mean age of the subjects was 42.1 +/- 0.7 years; 77% white male, and 97% Chinese. About 108 patients (56%) had recent screening. At multivariate analysis, only the ability to remember date of follow-up (OR: 4.37; 95% CI: 2.07-9.17) and the perception of having to wait a long time for venepuncture (OR: 0.38; 95% CI: 0.19-0.79) were significantly associated with recent screening. CONCLUSION: Future public health measures should include improving the logistics of follow-up procedures and providing reminders for screening to improve compliance.

Adult↗
PubMed2004

The majority of hepatitis B carriers are not on regular surveillance in Singapore.

INTRODUCTION: Carriers of hepatitis B virus (HBV) are at risk of developing long-term complications. Regular surveillance helps detect treatable chronic hepatitis, cirrhosis and liver cancer, and is recommended by practice guidelines in the United States, Europe and Singapore. However, there have been few studies evaluating the follow-up of HBV carriers. This study seeks to determine the proportion of HBV carriers on regular follow-up in Singapore and the impact on hepatitis B disease. METHODS: An advertisement was taken in local newspapers advertising for free screening to HBV carriers. 387 persons answered the advertisement. The screening comprised history-taking, physical examination, blood tests (liver panel, alphafoetoprotein, hepatitis B surface antigen (Ag) and hepatitis B eAg) and ultrasonography of liver. Further evaluation was conducted if the screening results were abnormal. RESULTS: Of the 387 HBV carriers, 346 (89 percent) were male and 375 (97 percent) were Chinese. Their mean age was 39 years (range 20-60 years) and 36 percent were positive for HBeAg. 247 (64 percent) were not on regular screening over the past 12 months. 19 (5.4 percent) patients were diagnosed to have complications, namely: 13 had HBeAg-positive chronic hepatitis, two had HBeAg-negative chronic hepatitis, one had early liver cancer who recovered well after a curative resection and three had compensated cirrhosis. CONCLUSION: Our screening programme diagnosed 5.4 percent of complications among 387 asymptomatic HBV carriers. However, 64 percent of the study subjects were not screened regularly and may pose an important public health threat if they develop long-term complications. Further studies are needed to evaluate and improve patient compliance for screening.

Adult↗
PubMed2002

Paclitaxel (Taxol) attenuates clinical disease in a spontaneously demyelinating transgenic mouse and induces remyelination.

Treatment with paclitaxel by four intraperitoneal injections (20 mg/kg) 1 week apart attenuated clinical signs in a spontaneously demyelinating model, if given with onset of clinical signs. If given at 2 months of age (1 month prior to clinical signs), disease was almost completely prevented The astrogliosis, prominent in our model, was reversed by paditaxel as determined by astrocyte counts and quantitation of GFAP. Electron microscopic examination of affected regions at 2.5 months demonstrated that the myelin was generally normal. By 4 months of age, demyelination was common in the superior cerebellar peduncle, maximal at 6 months, but continued to 8 months. In addition to myelin vacuolation and nude axons, the presence of many thin myelin sheaths suggested remyelination or partial demyelination. Although no evidence of oligodendrocyte loss was seen, nuclear changes were observed. To substantiate that remyelination was occurring, we measured MBP (18.5 kDa), MBP-exon II, Golli-MBP, TP8, Golli-MBP-J37, platelet-derived growth factor alpha (PDGFR alpha) and sonic hedgehog (SHH). Of these TP8, PDGFR alpha and SHH were up-regulated in the untreated transgenic. After paditaxel treatment, MBP-Exon II, TP8, PDGFR alpha and SHH were further up-regulated. We concluded that some of the effects of paditaxel were to stimulate proteins involved in early myelinating events possibly via a signal transduction mechanism.

Animals↗
PubMed1998

Mechanism of demyelination in DM20 transgenic mice involves increased fatty acylation.

Transgenic mice (ND4) containing 70 copies of the transgene encoding DM20 were clinically normal up to 3 months of age, spontaneously demyelinated there-after and died in 8-10 months. Whereas the myelin fraction from normal mice increased in amount from 1-4 months as expected, the corresponding fraction in ND4 mice remained constant over this period. In order to study the mechanism by which decreased myelin synthesis was manifest in the ND4 mouse, we investigated the amounts of proteolipids at various ages. The amount of proteolipid protein (PLP) was greatly decreased after 1-2 months in the ND4 mice. Although the message for DM20 was increased (transgene mRNA), very little DM20 was found in myelin at 1 month. It subsequently increased so that at 3-4 months the amount of DM20 in myelin isolated from transgenic animals was much higher than in normal mice. Characterization of the DM20 and PLP at 1 month of age showed that the amount of fatty acid (stearate and palmitate) was increased and the N-terminal glycine was methylated. These data suggested that high copy numbers of the cDNA for DM20 affected post translational events which we postulate affected the proper insertion of both DM20 and PLP in the myelin bilayer.

Acylation↗
PubMed1996

Modifications of myelin basic protein in DM20 transgenic mice are similar to those in myelin basic protein from multiple sclerosis.

Transgenic mice containing different numbers of transgenes (2-70) of the myelin proteolipid protein DM20 were phenotypically normal up to 3 mo of age, after which the mice containing 70 copies of the transgene spontaneously demyelinated and died at 10-12 mo. Since we demonstrated that demyelination in multiple sclerosis involved specific chemical changes in myelin basic protein (MBP), we investigated the MBP in our transgenic line for similar changes. Both the total amount of MBP in brain and the MBP mRNA levels were unaffected at the different ages. All the isoforms (14-21 kD) of MBP were present, but the microheterogeneity (a posttranslational event) was changed resulting in a higher proportion of the less cationic components reminiscent of the changes in MBP found in multiple sclerosis. An increased amount of the citrullinated form of MBP was found by Western blot analysis. Immunogold labeling of cryosections of brain revealed a greater density of particles with the anticitrulline antibody at 10 mo and that the levels of peptidylarginine deiminase (which deiminates protein-bound arginine to citrulline) were increased. This stable transgenic line represents a useful animal model for the human disease multiple sclerosis.

Animals↗
PubMed1991

The value of ultrasound mammography in palpable breast masses.

Between January 1987 and May 1988 a prospective study was carried out on 232 women with a palpable breast mass. They underwent physical examination, x-ray mammography and ultrasound mammography. The results of each study were interpreted independently by separate observers, and consensus was achieved. From all solid tumours histology was available. Compared to x-ray mammography, ultrasound mammography proved to be significantly (p less than 0.025) more sensitive in diagnosing malignant palpable breast masses (98.7% versus 86.8%). However there was no statistical significant difference in specificity between ultrasound mammography and x-ray mammography. Using ultrasound mammography we classified 9 histological proven malignant tumours as such which were negative on plain x-ray mammography. Despite the good results of ultrasound mammography in diagnosing palpable breast lesions it can never replace x-ray mammography in cases of malignancy, because the results of ultrasound mammography with non-palpable synchronous tumours with or without microcalcifications are poor. In some cases of benign lesions diagnosed with ultrasound mammography no x-ray mammography is necessary.

Adolescent↗
PubMed1986

An operative choledochoscopy using the flexible choledochoscope.

In a prospective study, the value of operative choledochoscopy as a completion procedure after standard instrumental exploration of the common bile duct is evaluated. The technique of examination using the flexible scope is described. Operative choledochoscopy was performed upon 320 patients. Retained stones of the biliary tract missed by exploration were detected in 23 patients (7.1 per cent). Stones retained in spite of endoscopic examination were found in five (1.6 per cent) of the patients. The comparison of the personal experience (158 patients) with the experience of other surgeons and registrars performing the biliary tract operations on their own at our institutions (178 patients) allows a conclusion that, if the technique of choledochoscopy is well standardized and correctly learned, no difference in results achieved is to be expect. Operative choledochoscopy is a reliable method of examination supporting valuable diagnostic information, contributing to the operative decision making and reducing efficiently the incidence of retained biliary tract stones.

Aged↗
PubMed1983

Postoperative choledochoscopy. A five-year experience.

In a five-year period postoperative choledochoscopy was used in 85 consecutive patients for therapeutic or diagnostic interventions in the biliary tract. Seventy-three patients underwent postoperative choledochoscopy for removal of retained biliary stones; 67 (92%) had successful removal of 94 retained stones; in 11 stones were located in the intrahepatic ducts; in six postoperative choledochoscopy failed; and in 12 postoperative choledochoscopy was performed for diagnostic or other therapeutic reasons. No serious complications were encountered in this series. The advantage of this simple and effective technique over other instrumental or so-called radiologic techniques is discussed. In our opinion, postoperative choledochoscopy is now the method of choice for diagnostic and therapeutic (re)interventions in the biliary tract by patients with a T tube still in situ.

Bile Duct Diseases↗
PubMed1979

Results of surgical treatment for hyperthyroidism.

UNLABELLED: In a 10-year period (1967-1977) 273 patients were operated upon for hyperthyroidism at the Department of Surgery of the St. Franciscus Gasthuis, Rotterdam. The evaluation of the results was carried out in 1978. A total of 205 patients appeared for investigations and drawing of blood samples. Total resection of one thyroid lobe and subtotal resection of the other lobe was the procedure of choce. RESULTS: 85% of the patients were euthyroid at the follow-up; 7% of the patients had a recurrent hyperthyroidism and 8% became hypothyroid. In three cases a persistent unilateral vocal cord paralysis was encountered. Surgery remains an effective and satisfactory method of treatment for appropriately selected cases, with a low rate of immediate and late complications.

Adolescent↗