Suppression of inducible cyclooxygenase and nitric oxide synthase through activation of peroxisome proliferator-activated receptor-gamma by flavonoids in mouse macrophages.

Peroxisome proliferator-activated receptor (PPAR)gamma transcription factor has been implicated in anti-inflammatory response. Of the compounds tested, apigenin, chrysin, and kaempferol significantly stimulated PPAR gamma transcriptional activity in a transient reporter assay. In addition, these three flavonoids strongly enhanced the inhibition of inducible cyclooxygenase and inducible nitric oxide synthase promoter activities in lipopolysaccharide-activated macrophages which contain the PPAR gamma expression plasmids. However, these three flavonoids exhibited weak PPAR gamma agonist activities in an in vitro competitive binding assay. Limited protease digestion of PPAR gamma suggested these three flavonoids produced a conformational change in PPAR gamma and the conformation differs in the receptor bound to BRL49653 versus these three flavonoids. These results suggested that these three flavonoids might act as allosteric effectors and were able to bind to PPAR gamma and activate it, but its binding site might be different from the natural ligand BRL49653.

Engineering bone regeneration with bioabsorbable scaffolds with novel microarchitecture.

Critical-sized defects (CSDs) were introduced into rat calvaria to test the hypothesis that absorption of surrounding blood, marrow, and fluid from the osseous wound into a bioabsorbable polymer matrix with unique microarchitecture can induce bone formation via hematoma stabilization. Scaffolds with 90% porosity, specific surface areas of approximately 10 m2/g, and median pore sizes of 16 and 32 microm, respectively, were fabricated using an emulsion freeze-drying process. Contact radiography and radiomorphometry revealed the size of the initial defects (50 mm2) were reduced to 27 +/- 11 mm2 and 34 +/- 17 mm2 for CSDs treated with poly(D,L-lactide-co-glycolide). Histology and histomorphometry revealed scaffolds filled with significantly more de novo bone than negative controls (p < 0. 007), more osteoid than both the negative and autograft controls (p < 0.002), and small masses of mineralized tissue (< 15 mm in diameter) observed within the scaffolds. Based on these findings, we propose a change in the current paradigm regarding the microarchitecture of scaffolds for in vivo bone regeneration to include mechanisms based on hematoma stabilization.

The growth-inhibitory effect of 4-hydroperoxycyclophosphamide against human non-small cell lung carcinoma is enhanced by low-dose difluoromethylornithine.

Surgically unresectable human non-small cell lung carcinoma (NSCC) is highly resistant to present chemotherapy and radiation therapy regimens. Cyclophosphamide, a potent alkylating agent, has shown some efficacy, especially in combination chemotherapy. Difluoromethylornithine (DFMO), a specific and irreversible inhibitor of ornithine decarboxylase (ODC) which produces minimal toxicity in animals and humans, has shown antiproliferative effect against human SCC in culture but a much smaller effect (cytostatic) against NSCC. We therefore investigated 4-hydroperoxycyclophosphamide (4HC) and DFMO alone and in combination against a human NSCC line (NCI-H157). Cells were treated with DFMO at graded concentrations of 0 to 800 microM from day 0 to day 7. On day 3, cells were exposed for 1 h to 4HC at graded concentrations of 0 to 80 microM, washed, and refed with media containing DFMO at initial concentrations. On day 7, cells were counted by hemacytometer. Cells treated with DFMO or 4HC alone exhibited dose-dependent growth inhibition. Growth inhibition by 4HC was enhanced through combination with DFMO. On day 7, 50 microM (5 x 10(-5) M) DFMO effected a 37% inhibition, 8 microM 4HC 47% inhibition, and the combination of 50 microM DFMO and 8 microM 4HC yielded an elevated 71% inhibition. The growth inhibitory effect and potentiating effect of DFMO were reversible upon addition of putrescine (PU) to the culture medium. The combination of DFMO and 4HC, two agents with different toxicity spectra, may represent an effective chemotherapeutic regimen for the treatment of lung cancer.

Effects of acculturation on the MMPI-2 scores of Asian American students.

The use of the MMPI-2 (Butcher, Dahlstron, Graham, Tellegen, & Kaemmer, 1989) with minorities has been questioned due to potential misinterpretations related to cultural differences. This study examined acculturative differences among Asian American college students and their scores on the validity and clinical scales. A sample of Asian American students (n = 90) was assigned to groups based on acculturation level. Analysis of variance tests indicated that low-acculturated, bicultural, and high-acculturated Asian Americans yielded different profiles. Compared to a matched White student sample, low-acculturated Asian Americans scored significantly higher on 9 scales, and bicultural Asian Americans had 6 significantly different scores. These differences were clinically interpretable with a range from 6.46 to 21.65 T-score points. High-acculturated Asian Americans did not differ from Whites. Cultural variables to be considered when interpreting Asian American profiles are discussed.

Preparation and in vitro evaluation of polylactic acid-mitomycin C microcapsules.

An emulsion method was developed for the incorporation of water-soluble mitomycin C into polylactic acid biodegradable microcapsules. With an average particle size of about 95 microns, microcapsules with a desired loading of from 3.65 to 13.80 per cent were prepared. These microcapsules, which contained both crystalline and finely dispersed drug particles, showed a dose-dependent drug release pattern with microcapsules of higher drug loading having a faster release rate than those of lower drug loading. Effective sterilization of the microcapsules for parenteral use was achieved by 60Co gamma-ray irradiation, which did not affect the microcapsule structure, release rate or drug stability. Mitomycin C showed dose-dependent antiproliferative activity against the growth of the K562 human erythroleukaemia cells. The microencapsulated dosage form of mitomycin C was found to enhance the drug's activity through sustained drug release. In experiments where drug concentrations in the cell medium were reduced according to the drug's biological half-life, the microcapsule systems showed a distinct advantage over the non-capsulated dose for the kinetic inhibition of K562 cell growth.

Ectopic bone formation via rhBMP-2 delivery from porous bioabsorbable polymer scaffolds.

Drug delivery devices have received considerable interest in the field of tissue engineering due to the advent of proteins that can induce proliferation and differentiation of various cells to form specific tissues and organs, for example, bone morphogenetic protein (BMP-2) for osteogenesis. In this work the delivery of a clinically relevant bioactive factor, recombinant human rhBMP-2, was tested in vivo in a rat ectopic bone induction assay. Contact radiography and radiomorphometry showed significantly more radiopacity (1798+/-183 mm2 versus. 784+/-570 mm2 radiopaque area/g scaffold) in the BMP scaffolds than controls (p < 0.002). De novo woven bone and abundant osteoid formation were confirmed from histological sections while controls contained minimal amounts of tissue. Histomorphometry revealed significantly more bone (124+/-93 mm2 versus 7+/-12 mm2) and osteoid (72+/-43 mm2 versus 20+/-21 mm2) in the BMP implants (p < 0.001). These scaffolds demonstrated the ability to deliver viable rhBMP-2 and to induce bone formation in an ectopic site.

Comparative study of timolol gel versus timolol solution for patients with glaucoma.

BACKGROUND: The timolol gel was developed for the simplification of multi-dose medications for glaucoma patients. This gel can be used once per day instead of twice per day of the aqueous form. It is necessary to understand the clinical effects of intraocular pressure maintained in glaucoma by there two forms of timolol. METHODS: Fifty-two eligible patients were included and completed the 12-week study. In this randomized, open-label, two-period crossover study design, patients received either the gel form of 0.5% timolol once daily or the aqueous form of 0.5% timolol twice daily for the first 6 weeks, then crossed over to the other treatment form for the remaining 6 weeks. Intraocular pressure was measured at baseline, week 6 and week 12 at the end of the treatment period. The incidences of all the adverse events were recorded and summarized in each follow-up visit. RESULTS: No statistically significant difference in intraocular pressure was observed between the two different control treatment groups (p>0.05). However, stickiness and transient blurred vision was reported more often by patients using the gel form than the aqueous form of timolol. CONCLUSIONS: The gel form of 0.5% timolol used once daily offers a new alternative that is probably more convenient than the aqueous form of 0.5% timolol given twice daily in maintaining the intraocular pressure of patients with glaucoma.

Elevated nitric oxide level in aqueous humor of patients with acute angle-closure glaucoma.

Nitric oxide, a noxious and free-radical gas, plays a key role in vasodilatation, inflammation, immunity, and neurotoxicity. Studies have shown that a recently detected NO synthase inducible isoform, found in astrocytes in the optic nerve heads of glaucoma patients, could stimulate excessive production of NO. The purpose of our study was to elucidate the role of NO production in the pathogenesis of glaucoma. We measured the concentrations of NO in aqueous humor from 11 patients with acute angle-closure glaucoma (AACG) and 14 patients with cataract. All samples were collected from patients who were free of any other systemic disease. Utilizing a chemiluminescence assay, we found that in AACG patients the NO levels in aqueous humor samples (83.2 +/- 6.7 microM) were significantly higher than in cataract patients (27.1 +/- 3.6 microM; p < 0.001). We therefore concluded that excessive NO in AACG patients reflects the degree of ocular impairment demonstrated by concomitant retinal cell and optic nerve cell damage.