OBJECTIVE: The aim of this study is to compare the in vitro proliferative capacity of periodontal ligament (PDL) cells from aged and juvenile donors. MATERIALS AND METHODS: Flow-cytometric analysis of the cell cycle was used to compare the length of each cell cycle, and the ratio of the cells progressing through the cycles between four PDL cells from juvenile donors and four cells from aged donors. Then, replicative capacity of the PDL cells from three juvenile and three aged donors was compared by serial cultureS. Finally, expression of c-fos was compared between cells proliferating and cells which had reached senescent. RESULTS: Flow-cytometric analysis of the cell cycle had revealed that although there were no differences in the length of each phase of the cell cycle, significant differences were found in the ratio of the cells entering from Gap 1 to DNA synthesis phase of the cell cycle ( P < 0.025).Replicative capacity was much longer in two cells from juvenile donors (about 20 population doublings), while all cells from aged donors showed short dividing abilities (less than eight population doublings), hence entered senescent phases shortly. Additionally, no c-fos was detected in cells which had reached senescence upon stimulation with serum. CONCLUSIONS: It is generally believed that aged humans have an impaired wound healing ability. We believe that more fibrotic PDL tissues seen in aged humans might be the reason for this, and suggest that this phenomena might be due to the progressive accumulation of senescent cell populations. 相似文献
This work was conducted to study the ability of bacterial and fungal isolates from keratitis cases in Upper Egypt to produce enzymes, toxins, and to test the isolated fungal species sensitivity to some therapeutic agents.
Materials and Methods:
One hundred and fifteen patients clinically diagnosed to have microbial keratitis were investigated. From these cases, 37 bacterial isolates and 25 fungal isolates were screened for their ability to produce extra-cellular enzymes in solid media. In addition, the ability of fungal isolates to produce mycotoxins and their sensitivity to 4 antifungal agents were tested.
Results:
Protease, lipase, hemolysins, urease, phosphatase, and catalase were detected respectively in 48.65%, 37.84%, 59.46%, 43.24%, 67.57%, and 100% out of 37 bacterial isolates tested. Out of 25 fungal isolates tested during the present study, 80% were positive for protease, 84% for lipase and urease, 28% for blood hemolysis, and 100% for phosphatase and catalase enzymes. Thirteen fungal isolates were able to produce detectable amounts of 7 mycotoxins in culture medium (aflatoxins (B1, B2, G1, and G2), sterigmatocystin, fumagillin, diacetoxyscirpenol, zearalenone, T-2 toxin, and trichodermin). Among the antifungal agents tested in this study, terbinafine showed the highest effect against most isolates in vitro.
Conclusion:
In conclusion, the ability of bacterial and fungal isolates to produce extracellular enzymes and toxins may be aid in the invasion and destruction of eye tissues, which, in turn, lead to vision loss. 相似文献
A 69-year-old female patient presented heart failure with preserved ejection fraction and atrial fibrillation. Echocardiography and late gadolinium enhancement magnetic resonance imaging were suggestive of endomyocardial fibrosis (EMF). The patient underwent cardiac surgery, and after surgery, she developed low cardiac output syndrome and died. Postmortem examination revealed residual fibrosis of the left ventricle (LV), mild endocardial fibrous deposition of the right ventricle, and severe concentric, symmetrical LV hypertrophy. Histological examination of the surgically resected material from the LV confirmed EMF. Histopathology of the interventricular septum disclosed myocardial hypertrophy and disarray plus fine interstitial fibrosis, typical of hypertrophic cardiomyopathy. The present case illustrates the association of two different patterns of cardiomyopathies in the same patient. 相似文献
PANGMA nanofibers and nanomats with fiber diameters of 200–300 nanometers were fabricated by electrospinning. Cal‐B was covalently immobilized onto the PANGMA nanomats via three different immobilization routes. The properties of the Cal‐B‐immobilized PANGMA nanomats were assayed and compared with the free Cal‐B. The observed Cal‐B loading on these nanomats is up to ≈50 mg · g?1, and their hydrolytic activity is up to ≈2 500 nmol · min?1 · mg?1, much higher than free enzyme powder and also slightly higher than Novozyme 435. Cal‐B immobilized PANGMA nanomats have better reusability, thermal stability, and storage ability than free Cal‐B. They retain over 50% of their initial activity after 15 cycles, over 65% after 10 h heat incubation, and over 75% after 30 d storage.
