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Biomedical subjects

H Y Lau

Publications and source records attributed to H Y Lau.

At least 19 recordsLinked to original sources
PubMed2001

Surgical confirmation of ProstaScint abnormalities in two patients with high risk prostate cancer.

We describe our initial experience using ProstaScint scanning in addition to conventional imaging modalities for staging of high risk prostate cancer. Using our protocol, ProstaScint images detected abnormalities in pelvic lymph nodes not seen on CT scan or magnetic resonance imaging (MRI) in two patients. Subsequent surgical pelvic lymphadenectomy confirmed these abnormalities. Further patients will be accrued on this study to estimate the sensitivity and specificity of ProstaScint scanning.

Aged↗
PubMed2000

Enhanced accuracy of needle placement in horizontal stereotactic core biopsy by a plastic slot.

Horizontal stereotactic core biopsy can be used in the investigation of clinically occult mammographic abnormalities especially when breast thickness is less than 3 cm. We designed a 6-mm plastic slot that can be inserted between the bushing and the biopsy gun to enhance the accuracy of needle placement within the lesion. With this device, the centre of the lesion can be targeted at the centre of the biopsy trough. We advocate the use of this piece of small, simple and inexpensive instrument in every case of horizontal stereotactic core biopsy.

Biopsy, Needle↗
PubMed2000

Characterization of prostanoid receptors mediating inhibition of histamine release from anti-IgE-activated rat peritoneal mast cells.

1. Prostanoid receptors mediating inhibition of anti-IgE induced histamine release from rat peritoneal mast cells have been characterized pharmacologically. PGD2 and the specific DP receptor agonists BW 245C and ZK 118182 were the most potent inhibitors with half-maximal concentrations of 0.26, 0.06 and 0.02 microM respectively. The maximum inhibition attainable was 60-65% with 10(-5) M BW 245C and ZK 118182. 2. Among several EP receptor agonists investigated, only PGE2 and the EP2/EP3 receptor agonist misoprostol induced significant inhibition (46.8 +/- 4.7% at 10(-4) M and 18.7 +/- 6.8% at 10(-5) M respectively). The IP receptor agonists cicaprost and iloprost were both less potent than the DP agonists in inhibiting histamine release (45.2 +/- 3.3% and 35.1 +/- 2.5% inhibition respectively at 10(-5) M), whereas PGF2 alpha and the TP receptor agonist U-46619 were only marginally effective. 3. The EP4/TP receptor antagonist AH 23848 failed to affect the inhibitory actions of PGD2 or PGE2 even at 10(-5) M, whereas the DP/EP1/EP2 receptor antagonist AH 6809 slightly enhanced the effect of PGD2 at 10(-6) M. 4. At concentrations of 3 x 10(-6) to 10(-5) M, the putative DP receptor antagonist ZK 138357 dose-dependently suppressed the inhibitory activities of the DP agonists, PGE2 and cicaprost. The antagonism of ZK 138357 against the DP receptor agonists appeared to be competitive with pA2 values of around six. 5. In conclusion, these data support our earlier proposal that an inhibitory DP receptor is the predominant prostanoid receptor in rat peritoneal mast cell. The properties of this receptor in relation to putative DP receptor subtypes reported in the literature are discussed.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1999

Large needle core biopsy--avoidance of biopsy table bombardment by the biopsy needle in stereotactic guided breast biopsy.

Table bombardment by automated biopsy needle is an occasional technical problem during stereotactic core biopsy of the breast. It is most commonly encountered in small breasts and when lesions are close to the biopsy table. A reference chart is devised for stereotactic core biopsy using an add-on erect stereotactic biopsy table and automated spring-loaded biopsy gun. The chart serves as a reference for pre-biopsy assessment of the feasibility of core biopsy in the vertical approach due to the constraints of lesion depth and breast thickness. It allows easy and quick reference for the required needle length input for the stereotactic system to prevent table bombardment.

Biopsy, Needle↗
PubMed1999

Primary Swenson pull-through compared with multiple-stage pull-through in the neonate.

BACKGROUND: In Hirschsprung's disease, the trend has been for earlier performance of definitive surgery. In our institution, primary Swenson pull-through has become the preferred procedure. METHODS: Retrospective review of the patients treated for Hirschsprung's disease from January 1988 through March 1998 was performed. Sixty-five patients were identified. Median values, analysis of variance and x2 were used for comparisons. RESULTS: The multiple-stage group (M, n = 47) was similar to the primary group (P, n = 18) for gestational age (40 v 39 weeks), time to meconium passage (37.9 v 35.5 hours), and age at diagnosis (median, M 27 vP 3.5 days). Age (median, M 268 vP 5 days) and weight (mean, M 9.4 v P 3.7 kg; P < .001) at pull-through were lower in the primary group. Length of stay (LOS) was lower in the primary group (mean, M 40.8 vP 20.3 days; P < .05). Operating time for pull-through was decreased in P (mean, M 305.2 v P 272.2 minutes; P = .02). Total complications were lower in the primary group (P = .03), with no differences in mortality or enterocolitis rates. CONCLUSIONS: At our institution there were no increases in total complications or enterocolitis in the group undergoing primary Swenson. Primary pull-through is a viable option for the treatment of Hirschsprung's disease.

Analysis of Variance↗
PubMed1998

Inhibition of rat peritoneal mast cell exocytosis by frusemide: a comparison with disodium cromoglycate.

Among the loop diuretics, frusemide possesses unique airway protective activities which may be due to the inhibition of airway inflammatory cells such as the mast cell. We previously reported that frusemide and disodium cromoglycate (DSCG) demonstrated a similar profile of inhibitory activities against histamine release from rat peritoneal mast cells activated by various stimuli which increased intracellular calcium via different routes. Furthermore, the inhibitory activities of both compounds demonstrated marked tachyphylaxis and we hence postulated that frusemide and DSCG might share the same mechanism of action which involves the prevention of extracellular calcium influx into the mast cell cytoplasm. The present study confirmed the postulation by (a) demonstrating that cross-tachyphylaxis exists between the two compounds and (b) extending the observations on histamine release to the influx of extracellular calcium (45Ca) into rat peritoneal mast cells.

Animals↗
PubMed1998

Orbital lymphoma: results of radiation therapy.

Orbital lymphoma is a rare presentation of non-Hodgkin's lymphoma. Treatment with radiotherapy is well-established. Twenty cases of orbital lymphoma treated at the Singapore General Hospital with radiation therapy were reviewed. All patients had improvement of their initial presenting symptoms and complete remission after radiation. Long-term local control was achieved in 17 of 20 (85%) of the treated orbits.

Adult↗
PubMed1996

Inhibition of rat peritoneal mast cell exocytosis by frusemide: a study with different secretagogues.

It has been reported that the loop diuretic frusemide can prevent exercise induced asthma, and that this effect may be due to the inhibition of mast cells in the airway. By using various mast cell secretagogues which increase intracellular calcium via different routes, this study attempted to elucidate the mechanism of the mast cell stabilizing action of frusemide. As well as confirming that immunologically induced histamine release from rat peritoneal mast cells was dose dependently inhibited by frusemide (10(-3) - 10(-5) M), the present study has extended the observation to histamine release induced by compound 48/80. The inhibitory potency was however less in the case of compound 48/80 induced release. Frusemide induced inhibition by the two secretagogues was decreased by drug preincubation. In contrast, histamine release induced by ionophore A23187 and thapsigargin was not inhibited by frusemide. The prototype antiallergic compound disodium cromoglycate (DSCG) demonstrated a similar specificity pattern against the various secretagogues. Another loop diuretic, bumetanide, did not show the same results as frusemide on rat peritoneal mast cell degranulation. Hence it is concluded that frusemide does not inhibit immunological activation of mast cells via its diuretic Na+/K+/Cl- co-transporter capacity. Instead, it protects mast cells in a similar manner to DSCG.

Animals↗