Prolylhydroxyproline (Pro-Hyp), which is derived from collagen hydrolysate, has been shown to be beneficial for skin and joint health. However, little is known about the distribution of Pro-Hyp in these tissues. In the present study, we investigated the biodistribution of orally administered [ 14 C]Pro-Hyp in rats. Whole-body autoradiography at 30 min after administration of [ 14 C]Pro-Hyp showed that radioactivity is widely distributed in tissues including skin and articular cartilage, with the highest level of radioactivity observed in the gastric and intestinal walls. Incorporation of radioactivity into cells known to respond to ProHyp such as dermal fibroblasts, synovial cells, chondrocytes, osteoblasts, and osteoclasts was observed. The chemical form of [ 14 C]Pro-Hyp-derived radioactivity detected in the tissues was investigated by thin layer chromatography. The radioactive constituents in cartilage extract were two proline-modified peptides (56%), intact Pro-Hyp (5%), and two nonpeptide metabolites (28%). Similar results were obtained for skin and bone marrow. Plasma analysis at 3 to 30 min post-dose suggested that the majority of Pro-Hyp is modified in its proline residue by a first-pass effect without peptide bond hydrolysis. In conclusion, we demonstrated that Pro-Hyp is partly distributed in observed tissues including skin and cartilage in its intact form, which might be responsible for its biological functions.

Subconjunctival administration of micafungin was effective in the treatment of experimental Candida keratitis. Local application of micafungin to the eye would be a feasible treatment option for clinical fungal keratitis.

We investigated the effects of hyperthermia on the healing process of experimental Pseudomonas corneal ulceration (PCU). Hartley guinea pigs were used to develop animal models of PCU. As a heat source, disposable chemical pocket warmers were applied. The healing process of PCU was compared between the heat-treated corneas and the control corneas. The severity of infection and the degree of angiogenesis were classified by a clinical scoring system. The animals were euthanized 14 days after infection and the corneas were submitted for histopathological examination. The expression of vascular endothelial growth factor (VEGF) was examined immunohistochemically. Comparative reverse transcription polymerase chain reaction was performed to measure the expression level of VEGF in the cornea. Hyperthermia significantly promoted corneal epithelization and neovascularization in the PCU model. Heat treatment significantly decreased the number of viable Pseudomonas organisms present in PCU. On immunohistochemistry, the heated cornea demonstrated more intense staining for VEGF. Comparative reverse transcription polymerase chain reaction showed upregulation of the expression level of VEGF mRNA in the heat-treated cornea. Hyperthermia accelerated the healing process of PCU with increased corneal neovascularization. Angiogenesis may play an important role in the PCU healing process, which is enhanced by the heat treatment.

There have been no reports of the topical application of micafungin to the eye. The aim of this study was to evaluate the safety of topical instillation of 0.1% micafungin ophthalmic solution in rabbit eyes. In New Zealand white rabbits (n = 6), 50 microL of 0.1% micafungin solution was topically instilled to 1 eye, and 50 microL of sterile saline was applied to the other eye. Both eyedrops were administered hourly from 7 A.M. for 7 days. Measurements were conducted on corneal thickness, intraocular pressure, endothelial cell density, and lactate dehydrogenase (LDH) activity of tear samples. The eyes were examined slit-lamp biomicroscopically and histopathologically. Topical micafungin application for 1 week did not induce any changes in intraocular pressure, endothelial cell density, and tear LDH. Corneal thickness after instillation was slightly, but significantly, smaller in the micafungin group than in the control group (P = 0.0156, paired t test), but this difference disappeared within 24 hours after the final instillation. Biomicroscopy and histopathology revealed no significant toxic influence of micafungin application on the cornea. Topical instillation of micafungin solution had no apparent toxicity to the cornea. These results warrant future studies on the efficacy of micafungin ophthalmic solution against corneal fungal infection.

A marked difference in the healing process of the inferior vena cava in rats following a stab with a 17-G (1.48 mm phi) ultrahard zirconium ceramic (Zr) needle and with a common stainless steel (St) needle (also 1.48 mm phi was observed. This was investigated in vivo by histological imaging and biochemical micro-autoradiographic imaging using [2-(14)C]-thymidine as a biomarker in vivo. On the first day after the stab with either, the Zr or the St injection needle, the tunica adventitia showed the most pronounced damage, as evidenced by a large puncture wound characterized by blood congestion, but with few inflammatory cells being observed. A marked contraction of the tunica media was observed. The depth of the injury reached the tunica layer, but amounted to less than 1/3 of the needle diameter. Loose fragments of the endothelial lining were detected, together with scattered red corpuscles. The survival rate of the experimental animals amounted to less than 40% on the 3rd day after the stab by either the Zr or St needle, due to the large needle diameter. In addition, histological imaging of the wound area in the endothelial layer and tunica media showed considerable congestion and inflammation, which limited the evaluation of the regeneration status of the inferior vena cava of the surviving animals. Results were obtained from a few animals that displayed satisfactory recovery status. On the 3rd day after the stab by either the Zr or St injection needle, a relatively large proportion of the hemostatic clots became incorporated into the collagenous tissue, i.e. the tunica adventitia. A marked contraction of the tunica media was also observed, similar to that on the 1st day, following the needle injury. In the case of the endothelium (tunica intima), the injury caused by the Zr needle was reinfiltrated by adult stem cells 3 days after the stab, but the tunica media, composed of endothelial cells, still contained relatively contracted collagenous material. In addition, several interesting cell colonies were observed in the medial layer at the short distance from the boundary of the damaged tissue. It was assumed that these colonies produced medial tissue composed of collagenous supporting tissue or smooth muscle cells. In the experiment using the St needle, the incorporation of [2-(14)C]-thymidine into the nucleus of the stem cells was observed in the small capillaries of the tunica media, but not in the support cells of the latter.