Effect of rapidly resorbable bone substitute materials on the temporal expression of the osteoblastic phenotype in vitro.

Ideally, bioactive ceramics for use in alveolar ridge augmentation should possess the ability to activate bone formation and, thus, cause the differentiation of osteoprogenitor cells into osteoblasts at their surfaces. Therefore, in order to evaluate the osteogenic potential of novel bone substitute materials, it is important to examine their effect on osteoblastic differentiation. This study examines the effect of rapidly resorbable calcium-alkali-orthophosphates on osteoblastic phenotype expression and compares this behavior to that of beta-tricalcium phosphate (TCP) and bioactive glass 45S5. Test materials were three materials (denominated GB14, GB9, GB9/25) with a crystalline phase Ca(2)KNa(PO(4))(2) and with a small amorphous portion containing either magnesium potassium phosphate (GB14) or silica phosphate (GB9 and GB9/25, which also contains Ca(2)P(2)O(7)); and a material with a novel crystalline phase Ca(10)[K/Na](PO(4))(7) (material denominated 352i). SaOS-2 human bone cells were grown on the substrata for 3, 7, 14, and 21 days, counted, and probed for an array of osteogenic markers. GB9 had the greatest stimulatory effect on osteoblastic proliferation and differentiation, suggesting that this material possesses the highest potency to enhance osteogenesis. GB14 and 352i supported osteoblast differentiation to the same or a higher degree than TCP, whereas, similar to bioactive glass 45S5, GB9/25 displayed a greater stimulatory effect on osteoblastic phenotype expression, indicating that GB9/25 is also an excellent material for promoting osteogenesis.

Comparative sensitivity of fluorescent antibody staining of conjunctival scrapings and irradiated McCoy cell culture for the diagnosis of hyperendemic trachoma.

The sensitivity of an indirect fluorescent antibody (FA) staining technique for detecting chlamydial inclusions in scrapings from the whole conjunctiva (upper tarsus, upper fornix, and lower lid) was compared with the sensitivity of culture in irradiated McCoy cells for the diagnosis of hyperendemic trachoma. In a group of 211 patients with various grades of active trachoma from the Bandar Abbas area of Southern Iran 42 patients were positive for chlamydiae by either method. There was little difference between the rates of positivity of FA staining of the scrapings from the whole conjunctiva (28 positives) and culture in irradiated McCoy cells (32 positives). In the patients included in this study chlamydial inclusions were detected in 15 eyes by examination of FA stained scrapings taken from the upper tarsal conjunctiva, whereas inclusions were detected in 40 eyes by the additional examination of scrapings taken from the upper fornix and lower lid (P less than 0.001). The examination of FA stained scrapings taken from the whole conjunctiva and spread as a single but larger smear may provide a satisfactory alternative to cell culture methods for the diagnosis of trachoma, particularly for field studies when cell culture facilities are not available.

Family-based suppressive intermittent therapy of hyperendemic trachoma with topical oxytetracycline or oral doxycycline.

A controlled double-blind stratified trial was carried out in a village in Southern Iran to assess the efficacy of family-based intermittent therapy of hyperendemic trachoma with topical oxytetracycline oily suspension twice daily for 7 days each month, or oral doxycycline 5 mg per kilogram of body weight once a month, in comparison with a control group which received vitamin pills once a month. In addition all other members of the selected children's families were also treated with the same regimen of therapy. The treatment was given for a period of 1 year by 3 field technicians, each responsible for one regimen of therapy. Examining the whole conjunctiva 4 months after the start of therapy, we observed no marked difference in the cure rate or the number of patients with moderate to severe trachoma between the groups treated with antibiotics and the control group. When treatment was continued for 12 months, a marked decrease in the prevalence of trachoma and in the grades of intensity of inflammatory responses as well as the positivity rate for Chlamydia trachomatis was observed in the groups treated with the topical oxytetracycline or oral doxycycline compared with the control group. While there was no marked difference between the efficacy of these 2 regimens of mass chemotherapy, the monthly intermittent therapy with a single dose of doxycycline offers the advantage of being more practical and less expensive for mass control of trachoma by requiring approximately one-tenth of the staff, transport, and other facilities required for the intermittent topical therapy with tetracycline eye ointment.

Isolation of Chlamydia trachomatis from eye secretion (tears).

Shedding of Chlamydia trachomatis in the eye secretion (tears) of patients with either hyperendemic trachoma or paratrachoma was studied. The method of collection of eye secretion with cellulose sponges is proved to be simple, faster, and more practicable and yielded a higher rate of chlamydial isolation than aspiration. The chlamydial isolation rates in eye secretion in chlamydia-positive paratrachoma patients in London or trachoma patients in Iran was 84 and 49% respectively. It was found that the chlamydial isolation rate from eye secretion is directly related to the number of inclusions present in the conjunctival swabbings. The results of this study indicated that patients with moderate to severe hyperendemic trachoma or paratrachoma are the main reservoir of infection. In the developing countries of the Middle East and Africa the shedding of chlamydia in the eye secretion of persons with these diseases is a major factor in the transmission of them by means of flies, fingers, towels, or bed clothes.