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S Siu

Publications and source records attributed to S Siu.

36 records · Page 2Linked to original sources
PubMed1998

Evidence that vitamin D3 increases serum 25-hydroxyvitamin D more efficiently than does vitamin D2.

In all species tested, except humans, biological differences between vitamins D2 and D3 are accepted as fact. To test the presumption of equivalence in humans, we compared the ability of equal molar quantities of vitamin D2 or D3 to increase serum 25-hydroxyvitamin D [25(OH)D], the measure of vitamin D nutrition. Subjects took 260 nmol (approximately 4000 IU) vitamin D2 (n=17) or vitamin D3 (n=55) daily for 14 d. 25(OH)D was assayed with a method that detects both the vitamin D2 and D3 forms. With vitamin D3, mean (+/-SD) serum 25(OH)D increased from 41.3+/-17.7 nmol/L before to 64.6+/-17.2 nmol/L after treatment. With vitamin D2, the 25(OH)D concentration went from 43.7+/-17.7 nmol/L before to 57.4+/-13.0 nmol/L after. The increase in 25(OH)D with vitamin D3 was 23.3+/-15.7 nmol/L, or 1.7 times the increase obtained with vitamin D2 (13.7+/-11.4 nmol/L; P=0.03). There was an inverse relation between the increase in 25(OH)D and the initial 25(OH)D concentration. The lowest 2 tertiles for basal 25(OH)D showed larger increases in 25(OH)D: 30.6 and 25.5 nmol/L, respectively, for the first and second tertiles. In the highest tertile [25(OH)D >49 nmol/L] the mean increase in 25(OH)D was 13.3 nmol/L (P < 0.03 for comparison with each lower tertile). Although the 1.7-times greater efficacy for vitamin D3 shown here may seem small, it is more than what others have shown for 25(OH)D increases when comparing 2-fold differences in vitamin D3 dose. The assumption that vitamins D2 and D3 have equal nutritional value is probably wrong and should be reconsidered.

Adult↗
PubMed1997

Latex allergy: epidemiological study of 1351 hospital workers.

OBJECTIVE: To determine the prevalence of latex sensitisation among a large group of healthcare workers, study the occupational and non-occupational factors associated with latex allergy, and characterise latex exposure in air and by gloves. METHODS: All 2062 employees of a general hospital in Hamilton, Ontario, Canada who regularly used latex gloves were invited to participate in a cross sectional survey, representing the baseline phase of a prospective cohort morbidity study. Attempts were made to recruit employees who were diagnosed with latex allergy before the survey. Glove extracts were assayed for antigenic protein, and area and personal air samples were obtained on two occasions (summer and winter) to estimate exposure to airborne latex protein. A questionnaire on medical and occupational information was administered by an interviewer. Skin prick tests were performed with latex reagents, three common inhalants, and six foods. RESULTS: The mean (SD) latex protein concentrations were 324 (227) micrograms/g in powdered surgical gloves and 198 (104) micrograms/g in powdered examination gloves. Personal latex aeroallergen concentrations ranged from 5 to 616 ng/m3. There was a total of 1351 (66%) participants. The prevalence of positive latex skin tests was 12.1% (95% confidence interval (95% CI) 10.3% to 13.9%). This prevalence did not vary by sex, age, hospital, or smoking status but subjects who were latex positive were significantly more likely to be atopic (P < 0.01). Participants who were latex positive were also significantly more likely to have positive skin tests to one or more foods (Mantel-Haenszel odds ratio (OR) adjusted for atopy 12.1, 95% CI 7.6 to 19.6, P < 10(-9)). Work related symptoms were more often reported among latex positive people, and included hives (OR 6.3, 95% CI 3.2 to 12.5), eye symptoms (OR 1.9, 95% CI 1.2 to 2.8), and wheezy or whistling chest (OR 4.7, 95% CI 2.8 to 7.9). The prevalence of latex sensitivity was highest among laboratory workers (16.9%), and nurses and physicians (13.3%). When the glove consumption per healthcare worker for each department was grouped into tertiles, the prevalence of latex skin test positivity was greater in the higher tertiles of glove use for sterile (surgical) gloves (P < 0.005) but not for examination gloves. CONCLUSIONS: In this large, cross sectional study of healthcare workers, the prevalence of latex sensitisation was 12.1% (9.5% among all those eligible), and there were significant associations with atopy, positive skin tests to certain foods, work related symptoms, and departmental use of gloves per healthcare worker. This cohort is being followed up prospectively and will be retested to determine the incidence of development of latex sensitivity.

Adult↗
PubMed1996

Percutaneous catheter closure of the persistently patent ductus arteriosus in the adult.

The USCI patent ductus occluder has been shown to be an effective nonsurgical technique for closure of the persistently patent ductus in a primarily pediatric population. Its clinical impact in the adult has been reported only within small subgroups of larger pediatric studies or for a small population. This study was conducted to determine the feasibility, success rate, and complications of device closure for the persistently patent ductus arteriosus (PDA) in the adult. The population consisted of 55 patients (4 men and 51 women; mean age 38.8 +/- 15.0 years) with follow-up of 2.2 +/- 2.1 years. All patients underwent echocardiography obtained as part of their follow-up assessment. The device was successfully placed in 54 patients, with 75% clinical and echocardiographic closure at the first follow-up assessment 2.4 +/- 2.6 months). One patient with initial clinical and echocardiographic evidence of closure was subsequently found to have an open ductus. Spontaneous closure (2 patients) or second implant (6 patients) resulted in 86% closure at the most recent assessment. Thus, the percutaneous PDA double-umbrella occluder device is a feasible and effective technique for closing persistent PDA in the adult and will result in occlusion of the shunt in most patients without the need for thoracotomy.

Adolescent↗
PubMed1996

Laparoscopic-assisted colorectal surgery. Lessons learned from 240 consecutive patients.

PURPOSE: To audit the development and outcomes of laparoscopic colorectal surgery at the Royal Brisbane Hospital. METHODS: Since July 1991, laparoscopic-assisted colectomy for benign and malignant colorectal disease has been performed on more than 300 patients at the Royal Brisbane Hospital. This paper summarizes the outcome for the first 240 patients who underwent a laparoscopic colorectal procedure. All laparoscopic data were collected prospectively, and for selected studies, data were compared with open surgical controls. RESULTS: Nineteen patients required open conversion (7.9 percent). There was a significant decrease in wound infection rates in patients having a laparoscopic-assisted colectomy (3.6 percent) compared with historical controls (7.9 percent) (P < 0.05; chi-squared). There were five anastomotic leaks, five laparotomies for postoperative adhesive obstruction, and four perioperative deaths. A total of 103 patients had a procedure for colorectal cancer. Of the 79 potentially curative procedures, there have been 5 (6.3 percent) recurrences to date. CONCLUSION: The overall morbidity and mortality in this series seem to be acceptable compared with that of open procedures.

Colonic Diseases↗
PubMed1996

Laparoscopic anterior resection: a consecutive series of 84 patients.

Laparoscopic colorectal surgery is in its infancy. From a series of over 200 colorectal procedures undertaken over the last 30 months, we have performed 84 anterior resections. In 55 women and 29 men, median age 64 years (range 32-86), median weight 72 kg (range 36-125), surgery was undertaken for benign pathology (n = 57) and adenocarcinoma (n = 27). Anterior resection was completed laparoscopically in 75 cases (89%) with a median operating time of 210 min (range 85-420). Minor morbidity occurred in 17 patients (20%) with major morbidity in 10 cases (12%). There was one post-operative death. Flatus was passed a median of two days (range 1-7) after surgery and feces at a median of four days (range 2-9). Total hospital stay was six days (range 2-33). Delayed morbidity during a maximum of 30 months' follow-up included two anastomotic strictures but no evidence of malignant seeding. Laparoscopic anterior resection appears both feasible and safe for both benign and malignant disease, with the caveat that long-term outcome in malignant disease is not yet available.

Adult↗
PubMed1995

[Serum lipid-associated sialic acid (LSA) in diagnosing and monitoring ovarian cancer].

Serum from 161 patients with ovarian cancer, 28 patients with benign gynecologic disorders and 22 healthy women, was assayed for levels of tumor marker LSA, which were compared with CA125. The results showed that in the patients with ovarian cancer, the sensitivities of LSA and CA125 for the patients prior to surgery were 83.0% and 92.5%, respectively; the sensitivities for the recurrent patients after surgery were 73.7% and 82.5% respectively. A total sensitivity of 89.5% was obtained by combination of both markers. The positive predictive value of LSA and CA125 for the patients with suspected tumor recurrence were 89.4% and 100%, respectively, and their corroborative rate with the postoperative courses were 94.4% and 100%, respectively. Thus serum assay of LSA, can be used in monitoring patients with ovarian cancer. The technique for determination of serum level of LSA is much more simple and less expensive than the radioimmuno-assay of serum level of CA125.

Biomarkers, Tumor↗
PubMed1994

Quantification of tricuspid regurgitation by means of the proximal flow convergence method: a clinical study.

Quantitation of valvular regurgitation remains an important goal in clinical cardiology. It has been described previously that with the use of color Doppler flow mapping, simple measurements of apparent jet size do not correlate closely with quantitative regurgitant indices. Recently the proximal flow convergence method has been proposed to quantify valvular regurgitation by analysis of the converging flow field proximal to a regurgitant lesion. Assuming hemispherical convergence, flow rate Q can be calculated as Q = 2 pi r2va, where va is the aliasing velocity at a distance r from the orifice. For maximal accuracy, previously validated correction factors must be used to account for the flattening effect of the isovelocity contours close to the orifice and for the actual sector angle subtended by the valve leaflets (alpha), to yield a flow rate formula Q = 2 pi r2va.(vp/vp - va).(alpha/180), where vp is the orifice velocity obtained by continuous wave Doppler. In 45 patients (35 in sinus rhythm, 10 with atrial fibrillation) with tricuspid regurgitation, regurgitant stroke volume, regurgitant flow rate, and regurgitant fraction were calculated using the proximal flow convergence method and were compared with values obtained by the Doppler two-dimensional echocardiographic method. Regurgitant stroke volumes (SV) calculated by the proximal flow convergence method correlated very closely with values obtained by the Doppler two-dimensional method with r = 0.95 (y = 0.94x + 0.99) and delta SV = -0.3 +/- 5.2 cm3. Regurgitant flow rates (Q) calculated by both methods showed a similar correlation: r = 0.96 (y = 0.97x + 45) and delta Q = 1.6 +/- 429 cm3/min.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

The effects of regurgitant orifice size, chamber compliance, and systemic vascular resistance on aortic regurgitant velocity slope and pressure half-time.

The determinants of the aortic regurgitant velocity profile have been investigated using computer and in vitro simulations in which regurgitant orifice area, ventricular and aortic compliance, and systemic vascular resistance could be independently varied. In the study, regurgitant fraction was altered, either by changing the size of the regurgitant orifice or by holding the regurgitant orifice constant and changing chamber compliance or systemic vascular resistance. Upon increasing regurgitant fraction by increasing the size of the regurgitant orifice, the slope got steeper and the pressure half-time shortened, the response anticipated in current clinical practice. However, when the regurgitant orifice was kept constant and regurgitation fraction was increased by increasing the systemic vascular resistance or by increasing the compliance of the left ventricle, slope became less steep and pressure half-time lengthened. Multivariate analysis was used to quantify the relationship of regurgitant fraction to slope and pressure half-time. When orifice area was allowed to vary, slope was related directly (multiple r = 0.78, p less than 0.001) and half-time was related inversely (multiple r = 0.66, p less than 0.001) to regurgitant fraction. With the orifice area fixed, however, directionally opposite responses were seen; slope varied inversely (multiple r = 0.87, p less than 0.001), whereas half-time varied directly (multiple r = 0.88, p less than 0.001) with regurgitant fraction. This study suggests that the utility of the slope and pressure half-time of the regurgitant velocity tracing in clinical practice relates to their ability to discriminate regurgitant orifices of differing sizes.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve Insufficiency↗
PubMed1989

Near-fatal septicaemia with Chromobacterium violaceum.

Chromobacterium violaceum is a Gram-negative organism which normally inhabits water and soil. Human infection is unusual and is associated with a high mortality rate. We describe a typical case of disseminated infection with Chr. violaceum in a male carpet cleaner. The possible origin and treatment of the infection is discussed.

Adult↗
PubMed1989

Worker exposure to lead titanate zirconate in an Ontario company.

An Ontario plant with 101 workers, producing and using the ceramic compound lead titanate zirconate (LTZ), was investigated. Although air lead levels were high in most plant areas, 82 workers not exposed to lead oxide but to LTZ in the process had normal blood lead levels. In addition, no radiographic changes or abnormal pulmonary function test results were detected in 61 examined workers. The particle size of LTZ was determined to be less than 5 micrometers, and the solubility of LTZ in body fluids was found to be significantly less than lead oxide. The authors postulate that the observed low toxicity of LTZ could be due to its low solubility in body fluids. Further studies of the toxicity of LTZ and other less soluble lead compounds are recommended.

Air Pollutants, Occupational↗
PubMed1987

Carcinoma of the anal canal.

During the period 1973 to 1982, 35 patients with carcinoma of the anal canal were seen at this hospital. The main form of treatment was abdominoperineal excision, unless specific contraindications to this procedure were present. Between 1982 and 1984, a further 18 such patients were seen; the primary method of treatment then was combination chemotherapy and radiotherapy. Abdominoperineal excision was reserved for those patients who failed to respond to therapy or whose carcinoma recurred during the period of follow-up. The over-all five-year survival rate for the first 35 patients was 50%; the actuarial disease-free survival at two years for those who went into complete remission was 78% in the 18 patients who were seen in the second part of the study. We conclude that conservative treatment by chemoradiation is of value in the management of anal carcinomas.

Adult↗
PubMed1986

Human T-cell receptor genes: organization, diversity, and polymorphism.

The analysis of 27 human beta cDNA clones has revealed striking insights as to the germ line, combinatorial, and somatic mechanisms that operate to diversify V beta gene segments. It appears that the repertoire of human V beta genes is limited to 60 or so functional gene segments. Deletional mapping together with the analysis of large DNA fragments by field inversion gel electrophoresis and the isolation of cosmid clones should permit us to map the entire human V beta gene family. The polymorphisms that are present in these V beta gene segments will facilitate a search for interesting disease associations. A detailed comparison of the mouse and human V beta loci should permit us to come to understand in more detail the evolutionary mechanisms that have created these fascinating gene families.

Base Sequence↗
PubMed1985

Intra-arterial infusions in the treatment of hydrofluoric acid burns.

Burns due to hydrofluoric acid are uncommon, but are severe injuries. The mode of action is discussed briefly and the routine management of these patients is outlined. The use of intra-arterial infusions of calcium gluconate is stressed, and case reports are given to support its use.

Accidents, Occupational↗
PubMed1980

The conjunctival goblet cell in pterygium formation.

Histological studies of pterygium pathology, reveals the presence of goblet cells liberally distributed throughout the epithelial surface. This feature poses medical and surgical implications which are discussed.

Conjunctiva↗