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Biomedical subjects

Y T Chan

Publications and source records attributed to Y T Chan.

At least 19 recordsLinked to original sources
PubMed2007

Ethyl acetate extract of Chinese medicinal herb Sarcandra glabra induces growth inhibition on human leukemic HL-60 cells, associated with cell cycle arrest and up-regulation of pro-apoptotic Bax/Bcl-2 ratio.

Sarcandra glabra (Thunb.) Nakai, colloquially known as Caoshanhu, is a Chinese medicinal herb with reported anti-tumor, anti-inflammatory, anti-viral and non-specific immunoenhancing properties. Although the plant has been clinically used for treating a variety of diseases, its bioactive ingredients are largely unknown and its mode of action has never been investigated. In this study, the anti-tumor property of ethyl acetate (EA) extract of S. glabra was investigated by determining its in vitro growth-inhibitory effects on a panel of human cancer cell lines of different histotypes. Growth inhibition of the EA extract on the cancer cells seemed to be selective, and the leukemic HL-60 was found to be the most responsive after 48 h of treatment (IC50=58 microg/ml). Flow cytometric studies further illustrated that the extract might interfere with DNA replication and thus arrested the cell cycle at S phase in the leukemic cells, followed by DNA fragmentation and loss of phospholipid asymmetry in the plasma membrane after 72 h of treatment. Concurrently, the pro-apoptotic Bax/Bcl-2 ratio was also up-regulated by more than 178% of the control level. All these findings suggested that the extract had initiated apoptosis to kill the leukemic cells. Results from this pioneer study help to establish a scientific foundation for future research and development of the bioactive ingredients in EA extract of S. glabra as efficacious anti-cancer agents.

Acetates↗
PubMed2001

An easy method to reduce anterior shoulder dislocation: the Spaso technique.

OBJECTIVE: To introduce the Spaso technique for reducing anterior shoulder dislocation by reporting the success rate of the Spaso technique performed by junior emergency medicine residents. DESIGN: Retrospective case series. SETTING: Urban accident and emergency department. PARTICIPANTS: Patients with anterior shoulder dislocations. INTERVENTIONS: The Spaso technique was applied by the emergency medicine residents to reduce anterior shoulder dislocation. RESULTS: The emergency medicine residents applied the Spaso technique to reduce 16 cases of anterior dislocated shoulder during the study period. The Spaso technique was successful in 14 of 16 cases. The overall success rate was 87.5% (95% CI 60.4, 97.8%). No complications were noted. CONCLUSION: A new method has been introduced for reduction of anterior shoulder dislocation by reporting the experience of junior residents. The Spaso technique is simple, effective and able to be performed by single operator. Although the sample size was small, the result of the study could provide background information for planning a properly designed randomised controlled trial to evaluate the Spaso technique.

Adult↗
PubMed1997

Improved treatment outcome in adult acute lymphoblastic leukemia using the intensive German protocol, a preliminary report.

Thirty-nine consecutive patients with acute lymphoblastic leukemia were treated with an intensive chemotherapy protocol. There were 23 males and 16 females with a median age of 37 years (range: 15-65). Eighteen patients had common ALL, seven had pre-B ALL, three early-precursor B ALL, seven T-ALL and four had aberrant expression of myeloid antigens (c-ALL in three and pre-B ALL in one). The median initial leukocyte count was 11.8 x 10(9)/l (range: 0.65-295). Cytogenetic result of the marrow was available in 16 of 39 patients (41 per cent) and showed Philadelphia positivity in six, a normal result in six and one each of t(4,11), t(1,19), hyperdiploidy and del 12p. Hepatosplenomegaly was present in about 20 per cent of the patients. L-Asparaginase-related hepatic toxicity was the commonest toxicity (48.7 per cent) during phase I of induction. Prolonged pancytopenia and hypoplastic death were common during phase II. With the use of growth factors during the neutropenic period of phase II induction, the rate of hypoplastic death was reduced from 40 per cent to 3 per cent. Common causes of treatment failure included early hypoplastic death (27.8 per cent) and leukemia relapses (50 per cent) while primary refractory leukemia, hepatic failure and perforated peptic ulcer contributed to 11.1, 5.5 and 5.5 per cent of the other deaths. A high complete remission (CR) rate (87.4 per cent) was achieved after phase I induction. The median event-free survival (EFS) was 8 months and the 3-year event-free survival was 43 per cent. This result compared favourably to the other regimens previously employed in our institution. In conclusion, satisfactory survival can be achieved with this intensive regimen. Good supportive care was however, essential to minimize toxicities.

Adolescent↗
PubMed1997

Highly successful long-term outcome of kidney transplantation in Chinese recipients: an enhancing race effect?

We report on 352 cadaveric kidney transplants and 294 living related transplants performed over a 25-yr period among the Chinese population of Hong Kong. There is a marked preference for transplanting male patients, especially from living donors, and we argue that this represents a cultural phenomenon within the Chinese population. The 10-yr graft survivals for related and cadaveric transplants are 86.2% and 67.4%, respectively. These figures are appreciably higher than corresponding figures in Caucasian populations. We show beneficial effects of using cyclosporin A, minimizing the cold ischemia time and avoiding very young and very old donors. There is a clear benefit of transplanting kidneys with zero or one mismatched HLA antigen against the recipient but no stepwise decrease in outcome as the number of mismatched antigens increases. There is close concordance between the outcome of living related grafts with zero, one, and two mismatched haplotypes against the recipient and no observable benefit of haplotype matching. We show that Chinese renal transplant recipients in other centers also have better long-term graft outcome than Caucasians, both for cadaveric and living related transplants. We draw attention to the existence of a detrimental "race effect" in other studies when Black recipients are compared with Caucasians and consider whether an enhancing race effect exists for Chinese or whether the better outcome reflects different underlying diseases in Chinese.

Actuarial Analysis↗
PubMed1996

A phase II study of single agent paclitaxel in patients at first relapse following initial chemotherapy for breast cancer.

This study was initiated to evaluate the safety and efficacy of 3-weekly paclitaxel given at 225 mg/m2 over 3 hours without colony stimulating factor support in patients at their first relapse following adjuvant therapy for breast cancer. Thirty patients were entered into the study; all were assessable for response and toxicity. All patients had received adjuvant/neo-adjuvant chemotherapy; 22 patients had had prior hormonal therapy and 26 previous adjuvant radiotherapy. The group was characterized by a short time to first relapse (median 7.5 months (range 2-43)) and widespread disease, with 22 patients having multiple disease sites including: nodes (43%), skin and soft tissue (43%), liver (40%), lung (37%) and bone (50%). A total of 219 cycles of paclitaxel were given, with a median of eight per patient. The major non-haematological toxicities were: grade 3 alopecia (82% cycles), grade 2/3 arthralgia/myalgia (26%), grade 2/3 fatigue (16%) and grade 2/3 peripheral nervous system toxicity (12%). Haematological toxicity was mainly neutropenia of short duration, with grade 4 counts documented in 16% of cycles. Thrombocytopenia was minimal and there were no significant hypersensitivity reactions. The objective response rate was 60% (95% CI 42.5-77.5) with one complete response and 17 partial responses. The median duration of overall response was 30 weeks (range 15-75+ (95% CI 25-33)) with a median survival time for all patients of 42 weeks (range 1-124+). This study demonstrates that paclitaxel 225 mg/m2 is well tolerated as a 3-hour infusion and can be given safely in an outpatient setting without routine use of granulocyte colony stimulating factor. The response rate is encouraging and shows that this regimen is effective in this poor prognosis patient population.

Adult↗
PubMed1993

Use of skin staples for fixation of T tubes and drains.

Stapled anchorage is safe and effective for T tubes and drains and is preferred to the conventional technique. Significant bile leaks never occur. Three and two staples are recommended for anchoring T tubes and drains, respectively.

Bile↗
PubMed1992

Endoscopic sphincterotomy in young patients with choledochal dilatation and a long common channel: a preliminary report.

An anomalous elongated pancreaticobiliary common channel encourages reflux up both the biliary tree and the pancreatic ductal system, resulting in progressive choledochal dilatation, cholangitis with ductal calculi, relapsing pancreatitis and malignant change. Transduodenal sphincteroplasty has been used to improve drainage from the abnormal channel. The use of endoscopic sphincterotomy (ES) to establish drainage and minimize the surgical risks is reported in six symptomatic patients with mild choledochal dilatation (common bile duct diameter less than 15 mm), a common channel less than 15 mm in length and a distal stenosis. This was successful in five patients, who have no further symptoms. ES failed in the only patient with an undilated common channel and this patient went on to have open surgery. We believe ES to be safe and effective in the treatment of selected cases of long common channel.

Bile Ducts↗
PubMed1992

Intestinal obstruction due to axial twisting of bowel in transmesenteric hernia.

A baby, born with gastroschisis, had an unrepaired large aperture in the mesocolon close to a short segment of colon. One day, the entire length of bowel proximal to the defect traversed the rent. The free segment of colon was affected by the resulting twist along the long axis of the bowel and became obstructed. A large mesenteric defect, albeit too wide to strangulate the bowel, is not totally innocuous and should always be closed.

Hernia, Ventral↗