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Biomedical subjects

D Koh

Publications and source records attributed to D Koh.

At least 109 records · Page 6Linked to original sources
PubMed1988

Combination therapy with microwave coagulation and intracavitary irradiation for bladder cancer. Technique and preliminary clinical results.

Twenty-five patients with transitional cell carcinoma of the bladder have been treated with combined therapy consisting of microwave regional coagulation and intracavitary irradiation. A remote-controlled after-loading system was utilized for the radiation therapy. The follow-up period ranged from 6 to 19 months with an average of 11.4 months. Tumor stages were Tis (n = 2), Ta or T1 (n = 17), T2 (n = 2), T3 (n = 3) and T4 (n = 1), and grades were G1 (n = 10), G2 (n = 11) and G3 (n = 4). In 23 patients (92%), there was no endoscopic or histologic evidence of tumor after the initial treatment. Heterotopic recurrences were found after 2 or 3 months in 3 patients who received microwave regional coagulation or intracavitary regional irradiation. Additional intracavitary whole bladder mucosal irradiation was performed for 10 patients with multiple tumors and frequent recurrent tumors. Nine patients had no recurrence (average follow-up 11 months). Our preliminary findings indicate that combination therapy of microwave coagulation and intracavitary irradiation is a useful treatment for bladder cancer.

Brachytherapy↗
PubMed1988

Microwave coagulation therapy for urinary bladder tumors.

A new device has been developed for microwave coagulation of urinary bladder tumors. Twenty-one patients with urinary bladder tumors were treated by irradiation with microwave energy of 2,450 MHz. Results were obtained as follows: (1) microwave coagulation was performed in 21 patients with transitional cell carcinoma of the urinary bladder. Excluding 4 patients who subsequently received radical cystectomy, 17 patients showed a complete response, although 2 patients subsequently developed recurrences in different parts of the bladder within the following several months. Histological examination of the excised specimen revealed complete eradication of the tumor in 2 patients. In the remaining 2 patients with high-stage tumor (T4), viable tumor cells were noted in the urethra or vaginal wall. (2) Although neither technical difficulties nor severe complications were encountered, transient urinary frequency and calcification of the bladder wall were noted. The results of this study indicate that microwave coagulation may be used in the treatment of both superficial and invasive tumors.

Aged↗
PubMed1988

A study of the mortality patterns of taxi drivers in Singapore.

The mortality patterns of taxi drivers in Singapore were studied by examining the death certificates of a group of taxi drivers from 1984 to 1986. The drivers were all members of Singapore's largest transport co-operative, with a fleet of 6,377 taxis. This represents over 60% of all taxis in Singapore. One hundred deaths occurred among the taxi drivers during these 3 years. The age and sex standardised mortality ratios (SMRs) were 0.70 in 1984, 0.72 in 1985, and 0.98 in 1986. For the whole period, the age and sex standardised SMR was 0.80 (95% CL 0.65-0.97). Leading causes of death were neoplasms (42%), coronary heart disease (24%), and cerebrovascular disease (15%). Age and sex standardised cause specific SMRs were 1.22 (95% CL 0.88-1.65) for neoplasms, 0.78 (95% CL 0.50-1.16) for coronary heart disease, 1.51 (95% CL 0.84-2.49) for cerebrovascular disease, and 1.03 (95% CL 0.28-2.63) for suicides and homicides. Death from all other causes was significantly lower than the general population (SMR 0.32, 95% CL 0.18-0.53). As compared to the general population, taxi drivers in Singapore do not appear to have an excess mortality risk for cancers, coronary heart disease, cerebrovascular disease or from all other causes of death. Their risk of violent death from homicide or suicide is low when compared to available reports from other countries.

Adult↗
PubMed1987

Microwave surgical treatment of the prostate: clinical application of microwave surgery as a tool for improved prostatic electroresection.

Microwave surgery as a tool for improved prostatic electroresection is introduced. Prior to electroresection the prostate was coagulated with 2,450 MHz of microwave which was emitted from the bipolar electrode of a specially designed probe. We conducted a comparative study of 35 patients with bladder neck obstruction. There was a microwave coagulation group treated with subsequent transurethral resection (TUR) and a conventional TUR group. Both groups were analyzed for the amount of blood loss, irrigant absorption and the frequency of complications. Both during and following surgery, the former group had a significant reduction in blood loss and had no complications. We conclude that the combination procedure of microwave coagulation and TUR can minimize the disadvantage of formal TUR and may be of value in the treatment of patients with both prostatic obstruction and of hemorrhagic diathesis as well as in high risk patients.

Adenocarcinoma↗
PubMed1987

Ulcerative colitis in Singapore: a clinical study of sixty-one patients.

Sixty-one consecutive cases of ulcerative colitis from the Department of Medicine, Singapore General Hospital, over a 16-year period (1971 to 1986) were reviewed. Mean duration of follow-up was 35.9 months (range 2 months to 16 years). Fifty-one (83.6%) cases were diagnosed in the last 8 years. Sex ratio was almost equal (males 30, females 31) and mean age was 38.2 years. All racial groups were affected but a predilection among Indians (21.3%) was observed. At presentation, the disease was mild in 36 (59.0%), moderate in 14 (22.9%) and severe in 11 (18.1%) patients. Fifty-two (85.2%) patients had symptoms of at least one month's duration before presentation. The 3 commonest symptoms were haematochezia (95.1%), diarrhoea (95.1%) and mucoid stools (83.6%). Extraintestinal manifestations of disease such as backache (8.2%), peripheral arthritis (6.5%), iritis (6.5%) and liver disease (1.6%) were uncommon. Severe intestinal complications include toxic megacolon (1.6%), colonic perforation (1.6%) and massive gastrointestinal haemorrhage (1.6%). Haematological and biochemical indices at presentation generally reflected the activity and severity of disease. The disease was limited to the rectum and sigmoid colon in 12 (19.7%) patients, extended up to the splenic flexure in 16 (26.2%), up to the hepatic flexure in another 16 (26.2%) and involved the whole colon in 17 (27.9%). Pseudopolyposis was present in 13 (21.3%) patients. Of 49 patients: (a) 18 (36.7%) had remission and were relapse free subsequently (b) 14 (28.6%) had infrequent relapses (less than 3 x/year) (c) 3 (6.1%) had frequent relapses (greater than 3 x/year) (d) 10 (20.4%) had chronically active disease (e) 4 (8.2%) had a short fulminant course terminating in death.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Effects of ageing on taxi driving.

The effects of ageing on taxi driving were studied on 256 drivers from the largest taxi co-operative in Singapore. 123 of the drivers were below 45 years (28-44 yrs.) while the other 133 were 45 years or older (45-63 yrs.). The older drivers had a significantly higher prevalence of glucosuria (p less than 0.05) and poor visual acuity (p less than 0.01). In addition, 31.6% of the older drivers had elevated blood pressure as compared to 21.9% of the younger drivers. Psychophysiological test scores for mean reaction times (p less than 0.01), psychomotor dexterity and eye-hand co-ordination (p less than 0.01) and reaction discrimination errors (p less than 0.05) were also significantly poorer for the older drivers. In spite of these findings, the working hours, the average mileage driven, and the accident records of the older drivers were comparable to that of the younger drivers, thus suggesting that age does not play a major role in affecting the work capacity or accident liability of the drivers.

Accidents, Traffic↗
PubMed1987

Transit time analysis of the forced expiratory spirogram of fire-fighters.

Analysis of the forced expiratory spirogram using time as the primary variable had been shown to be a promising method for detecting small airway dysfunction. This paper describes its application on 277 fire-fighters. Spirometry was performed when the fire-fighters were at rest and had not been fighting fires for the previous 24 hours. The best of three spirograms were used to compute the mean transit time (MTT). Through multiple linear regression analysis, age was the only factor that was significantly associated with MTT. The regression coefficients for age of smoking and non-smoking fire-fighters were nearly equal (0.011 and 0.010 seconds per year respectively). When 28 pairs of smoking and non-smoking fire-fighters were matched for age, duration of service, ethnicity and job groups, their average MTT were not significantly different. An increasing age-adjusted mean MTT was seen among the non-smoking fire-fighters with job groups requiring greater exposure to fire-fighting. Normal smokers had been shown to have a much greater regression coefficient for age on MTT when compared to normal nonsmokers. When compared with this study, the regression equation for MTT of non-smoking fire-fighters differed markedly from that of normal non-smokers and approached that of normal smokers. Coupled with the 'dose-response' relationship shown in the non-smoking fire-fighters, this study provides evidence of pulmonary dysfunction in fire-fighters. This pulmonary dysfunction may be localised in the small airways.

Adult↗
PubMed1985

Base-base mismatches. Thermodynamics of double helix formation for dCA3XA3G + dCT3YT3G (X, Y = A,C,G,T).

Thermodynamic parameters for double strand formation have been measured for the sixteen double helices of the sequence dCA3XA3G.dCT3YT3G, with each of the bases A, C, G and T at the positions labelled X and Y. The results are analyzed in terms of nearest-neighbors and are compared with thermodynamic parameters for RNA secondary structure. At room temperature the sequence (Formula: see text) is more stable than (Formula: see text) and is similar in stability to (Formula: see text) and (Formula: see text) are least stable. At higher temperatures the sequences containing a G.C base pair become more stable than those containing only A.T. All molecules containing mismatches are destabilized with respect to those with only Watson-Crick pairing, but there is a wide range of destabilization. At room temperature the most stable mismatches are those containing guanine (G.T, G.G, G.A); the least stable contain cytosine (C.A, C.C). At higher temperatures pyrimidine-pyrimidine mismatches become the least stable.

Base Composition↗