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Biomedical subjects

D W Lu

Publications and source records attributed to D W Lu.

30 records · Page 2Linked to original sources
PubMed1992

Stability studies of topical carbonic anhydrase inhibitor 6-hydroxyethoxy-2-benzothiazole sulfonamide.

A new carbonic anhydrase inhibitor, 6-hydroxyethoxy-2-benzothiazole sulfonamide (6-hydroxyethyoxyzolamide), was studied to determine its stability in aqueous solution from pH 2.9 to 9.2 at a constant ionic strength of 0.15 M. This newly synthesized derivative of ethoxyzolamide has demonstrated clinical efficacy for use as an ophthalmic drug to lower intraocular pressure. Drug solution in sealed ampules was placed in a constant temperature over either at two temperatures (75 and 85 +/- 0.2 degrees C) or four temperatures (75, 80, 85, and 90 +/- 0.2 degrees C). Samples were analyzed by known HPLC methods. The results indicated that 6-hydroxyethoxyzolamide is most stable at pH 4 to 5.5. The aqueous drug solutions at pH 7.0 and 8.0 were, nevertheless, sufficiently stable, based on extrapolation of kinetic data at high temperatures using the experimentally determined Arrhenius equation. The degradation compound was identified by spectral analysis to have a hydroxyl group substituting for the original -SO2NH2 group.

Administration, Topical↗
PubMed1992

[Investigations on ragweed pollens in the air in Qingdao District and its allergenicity].

A survey of the distribution of ragweed in Qingdao district was carried out. Ambrosia-artemisifolia has been found to be widespread in many areas. The results of the survey showed that ragweed pollen was the chief allergen of the district and that it was 18%-21.3% of total air-borne pollen in a year. Skin tests with Ambrosia allergen extracts showed a positive rate of 67.7% in 624 cases of pollinosis. Ragweed pollens have become the major allergic pollen, causing important pathogenesis with pollinosis in the district. Preventive measures must be taken to eradicate ragweed. Otherwise it certainly will spread all over China.

Air Pollutants↗
PubMed1991

A case of basophilic leukemia bearing simultaneous translocations t(8;21) and t(9;22).

We report a case of basophilic leukemia with simultaneous translocations of t(8;21) and t(9;22). The patient's clinical and hematologic findings were characteristic only of t(9;22) but not of t(8;21). This unusual cytogenetic phenomenon raises a challenge to the current concepts of primary chromosomal abnormalities in cancer.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

[Airway provocation test with ragweed pollenosis and late-phase reaction].

Ragweed pollen extract inhalation airway provocation test (APT) were studied in 55 patients with ragweed pollenosis. Single dosage of 9000 PNU ragweed extract was applied and positive response was defined as more than 35% fall in SGrs at the dose of PT35-Grs. Among 55 patients, positive APT was found in 27 case (49%), dual late-pase responses in 11 patients, single late-phase response only was found 2 patients in complicated asthma group. Late-phase response were well related to the increased specific IgE, and strong positive skin test response (wheal greater than 11 mm). The results suggested ragweed pollen was one of the important allergen causing bronchial asthma. There was airway hyperresponsiveness to ragweed pollen in some patients (20%) with ragweed pollenosis without asthmatic symptoms.

Adolescent↗
PubMed1990

The study of ocular hypotensive effect of 6-hydroxyethoxy-2-benzothiazole sulfonamide: a topical carbonic anhydrase inhibitor.

A newly synthesized topical carbonic anhydrase inhibitor, 6-hydroxyethoxy-2-benzothiazole sulfonamide (6-HS), was administered systemically and topically to alpha-chymotrypsin-induced glaucoma rabbits to evaluate its ocular hypotensive effect. A significant IOP lowering effect was observed after topical application of 50 microL of 3% 6-HS gel, but a dose of 50 microL of 3% 6-HS suspension failed to reduce IOP. The maximal magnitude of reduced IOP after topical gel instillation was 24.4%, very close to the result obtained following intravenous injection of 6 mg/kg of 6-HS (23.3%). However, the blood levels of 6-HS after topical instillation with 3% 6-HS gel was much lower than that following 6 mg/kg of 6-HS injected intravenously (less than 5%). Since a lower dose of 6-HS (1 mg/Kg) administered intravenously did not cause a significant drop in IOP, it is reasonable to deduct that the ocular hypotensive effect of 6-HS applied topically can then be attributed to the inhibition of intraocular carbonic anhydrase activity. It was also noted that a larger dose of intravenous administration of 6-HS (20 mg/Kg) had a more profound IOP and blood pressure reducing effect with moderate metabolic acidosis.

Animals↗
PubMed1990

Corneal and scleral penetration studies of 6-hydroxyethoxy-2-benzothiazole sulfonamide: a topical carbonic anhydrase inhibitor.

A newly synthesized topical carbonic anhydrase inhibitor, 6-hydroxyethoxy-2-benzothiazole sulfonamide (6-HS), was used as a model drug to determine its corneal and scleral permeabilities in rabbit eyes. The corneal permeability coefficient of 6-HS for short duration glaucoma and normal rabbit eye was not significantly different (its mean value was around 2.9 x 10(-6) cm/sec), while the corneal permeability coefficient for long duration glaucoma rabbit eye was 1.8 times greater than that for the normal eye. The sclera was found to have a higher permeability than the cornea in that after four hours perfusion the amount of drug which passed through the sclera was 11 times greater than that of the cornea. In addition, it was also noted that after topical instillation of 50 microL of 3% 6-HS gel the aqueous humor concentrations of 6-HS in short duration glaucoma eye and normal eye were not statistically different.

Administration, Topical↗
PubMed1989

[An identification of special antibodies for brucellosis].

Applying antigens of B. abortus and Y. enterocolitica 0:3, detection 88 sera of cattle in foci of Brucellosis was carried out by Dot-ELISA on nitrocellulose filter paper, and compared with conventional ELISA and SAT. The results showed that coincident rate of Dot-ELISA and ELISA was 98%. Their sensitivity was more than SAT. In contrast with others, the Dot-ELISA should differentiate Brucella antibody from antibody to Y. enter. 0:9. In addition, the method is a simple, Speed, stable, and very easy. The procedure should help clinical diagnosis and epidemiological investigation.

Animals↗
PubMed1989

Sequential observation of clinical and karyotypic evolution in a patient with myelodysplastic syndrome.

This paper reports an interesting case of myelodysplastic syndrome (MDS), whose bone marrow karyotype at diagnosis was 46, XY, t(16;17) (q12;q25). Fourteen months later, the disease transformed into erythroleukemia, and several correlative clones with hyperdiploid appeared at the same time. Thus, we consider that detecting karyotypic evolution may help evaluate the prognosis of MDS.

Anemia, Refractory↗
PubMedDate not supplied

Formulation factors for preparing ocular biodegradable delivery system of 5-fluorouracil microparticles.

Microparticles containing 5-fluorouracil (5-FU) were prepared using poly(DL-lactide-co-glycolide) with an oil-in-oil emulsion/solvent extraction technique. Particle characteristics including size distribution, 5-FU loading efficiencies, in vitro release and degradation were investigated. The dispersed phase was composed of PLG dissolved in dichloromethane, and the continuous phase was paraffin oil containing lecithin. 5-FU was successfully entrapped in the microparticles with trapping efficiencies up to 76%, loading level 10% w/v, and particle size 3 microm. Release profiles of 5-FU loaded microparticles were determined to follow a first-order-time relationship. An optimized preparation of 5-FU microparticles was achieved and was capable of controlling the release of 5-FU over 21 days with an in vitro delivery rate of 0.4 microg 5-FU/mg particles/day in the study. Preliminary animal studies indicated that the 5-FU loaded microparticles as an ocular delivery system showed no ocular toxicity and no significant inflammatory response in rabbits for 2 months. The 5-FU loaded microparticles approach, with PLG, might be a potential for the application of long-term delivery of hydrophilic drugs in the eye.

Animals↗
PubMedDate not supplied

Phenomenological theory on refrigeration effect of practical type-I superconductor.

In accordance with the phenomenological theory of thermodynamics, we discussed the Magnetocaloric effect of type-I superconductors, which are exposed to a varying magnetic field. It is concluded theoretically that the refrigeration effect is closely associated with demagnetization effect for practical specimens, which is different from the situation for ideal superconductor sample having no demagnetization effect. From the thermodynamic formulation of superconductivity, we deduced the integrating function of the thermal effect. By numerical calculation, we found a quantitative relation between the refrigeration effect and the demagnetizing factor which is determined by the shape of the sample.

Electric Conductivity↗