Objective To analyze the effects of tyrosinase on choroidal and retinal thickness and blood flow changes in guinea pigs,and to explore the role of tyrosinase in the development and progression of myopia.Methods A total of 30 three-week-old male tri-colored guinea pigs and 10 albino guinea pigs were selected and divided into four groups:control group(tri-colored hyperopic guinea pigs,with no intervention),albino group(albino myopic guinea pigs,with no inter-vention),myopia group(tri-colored myopic guinea pigs,with no intervention),and injection group[tri-colored hyperopic guinea pigs,injected with tyrosinase inhibitor(6 250 μg·L-1),100 μL per day].The experiment lasted for 4 weeks.The refractive status and axial length(AL)of the guinea pigs in each group were measured,along with ocular biometric param-eters related to axial length[anterior chamber depth,aqueous humor depth(AQD),central corneal thickness,lens diame-ter,vitreous chamber depth(VCD)].Optical coherence tomography was used to measure the retinal thickness,choroidal thickness(ChT),and choroidal blood perfusion(ChBP)in different regions of the guinea pigs.The tyrosinase activity in the vitreous and retina of guinea pigs in each group was measured.The expression levels of neurotransmitters in the vitre-ous and retina of guinea pigs in each group were detected.Results The differences in refractive status between the albi-no group and the control group at 0,2,and 4 weeks of the experiment were statistically significant(F=8.972,P＜0.05).At the 4th week of the experiment,the refractive status of the injection group was lower than that of the control group,and the AL was greater than that of the control group,with statistically significant differences(both P＜0.05).Further analysis of AL-related biometric parameters revealed that only AQD and VCD were associated with the changes in AL of guinea pigs in each group.At the 0th week of the experiment,the average retinal thickness of the control group was greater than that of the albino group,with a statistically significant difference(t=-9.007,P＜0.000 1).Moreover,the differences in reti-nal thickness in the outer retina across different directions and time points were statistically significant(all P＜0.05).The differences in retinal thickness between the control and albino groups were mainly concentrated in the outer retina.The ChT of the albino group was less than that of the control group,with a significant difference between groups(F=4.809,P=0.030).The ChBP of the control group was significantly higher than that of the albino group at 0,2,and 4 weeks of the experiment(all P＜0.05).At the 4th week of the experiment,the tyrosinase activity in the vitreous of the injection,albi-no,and myopia groups was lower than that of the control group,with statistically significant differences(all P＜0.05).The differences in neurotransmitters between the albino and control groups were mainly concentrated in the vitreous.In the retina,the ornithine level in the myopia group was higher than that in the albino and control groups,and the tryptophan levels in the myopia and control groups were higher than that in the albino group,with statistically significant differences(all P＜0.05).Conclusion Tyrosinase plays a crucial role in the development of myopia,regulating the development of refractive status by influencing the physiological properties of the retina and choroid.

Objective To analyze the effects of tyrosinase on choroidal and retinal thickness and blood flow changes in guinea pigs,and to explore the role of tyrosinase in the development and progression of myopia.Methods A total of 30 three-week-old male tri-colored guinea pigs and 10 albino guinea pigs were selected and divided into four groups:control group(tri-colored hyperopic guinea pigs,with no intervention),albino group(albino myopic guinea pigs,with no inter-vention),myopia group(tri-colored myopic guinea pigs,with no intervention),and injection group[tri-colored hyperopic guinea pigs,injected with tyrosinase inhibitor(6 250 μg·L-1),100 μL per day].The experiment lasted for 4 weeks.The refractive status and axial length(AL)of the guinea pigs in each group were measured,along with ocular biometric param-eters related to axial length[anterior chamber depth,aqueous humor depth(AQD),central corneal thickness,lens diame-ter,vitreous chamber depth(VCD)].Optical coherence tomography was used to measure the retinal thickness,choroidal thickness(ChT),and choroidal blood perfusion(ChBP)in different regions of the guinea pigs.The tyrosinase activity in the vitreous and retina of guinea pigs in each group was measured.The expression levels of neurotransmitters in the vitre-ous and retina of guinea pigs in each group were detected.Results The differences in refractive status between the albi-no group and the control group at 0,2,and 4 weeks of the experiment were statistically significant(F=8.972,P＜0.05).At the 4th week of the experiment,the refractive status of the injection group was lower than that of the control group,and the AL was greater than that of the control group,with statistically significant differences(both P＜0.05).Further analysis of AL-related biometric parameters revealed that only AQD and VCD were associated with the changes in AL of guinea pigs in each group.At the 0th week of the experiment,the average retinal thickness of the control group was greater than that of the albino group,with a statistically significant difference(t=-9.007,P＜0.000 1).Moreover,the differences in reti-nal thickness in the outer retina across different directions and time points were statistically significant(all P＜0.05).The differences in retinal thickness between the control and albino groups were mainly concentrated in the outer retina.The ChT of the albino group was less than that of the control group,with a significant difference between groups(F=4.809,P=0.030).The ChBP of the control group was significantly higher than that of the albino group at 0,2,and 4 weeks of the experiment(all P＜0.05).At the 4th week of the experiment,the tyrosinase activity in the vitreous of the injection,albi-no,and myopia groups was lower than that of the control group,with statistically significant differences(all P＜0.05).The differences in neurotransmitters between the albino and control groups were mainly concentrated in the vitreous.In the retina,the ornithine level in the myopia group was higher than that in the albino and control groups,and the tryptophan levels in the myopia and control groups were higher than that in the albino group,with statistically significant differences(all P＜0.05).Conclusion Tyrosinase plays a crucial role in the development of myopia,regulating the development of refractive status by influencing the physiological properties of the retina and choroid.

Hookworm infections are widely prevalent in tropical and subtropical areas, especially in low income regions. In the body, hookworms parasitize the proximal small intestine, leading to chronic intestinal hemorrhage and iron deficiency anemia. Occasionally, hookworms can cause overt gastrointestinal bleeding, but this is often ignored in heavily burdened individuals from endemic infectious areas. A total of 424 patients with overt obscure gastrointestinal bleeding were diagnosed by numerous blood tests or stool examinations as well as esophagogastroduodenoscopy, colonoscopy, capsule endoscopy or double-balloon enteroscopy. All of the patients lived in hookworm endemic areas and were not screened for hookworm infection using sensitive tests before the final diagnosis. The patients recovered after albendazole treatment, blood transfusion, and iron replacement, and none of the patients experienced recurrent bleeding in the follow-up. All the 31 patients were diagnosed with hookworm infections without other concomitant bleeding lesions, a rate of 7.3% (31/424). Seventeen out of 227 patients were diagnosed with hookworm infections in the capsule endoscopy (CE), and 14 out of 197 patients were diagnosed with hookworm infections in the double balloon enteroscopy (DBE). Hookworm infections can cause overt gastrointestinal bleeding and should be screened in patients with overt obscure gastrointestinal bleeding (OGIB) in endemic infectious areas with sensitive methods. Specifically, the examination of stool specimens is clinically warranted for most patients, and the proper examination for stool eggs relies on staff's communication.
Albendazole ; Ancylostoma ; Ancylostomatoidea* ; Anemia, Iron-Deficiency ; Blood Transfusion ; Capsule Endoscopy ; Colonoscopy ; Diagnosis ; Double-Balloon Enteroscopy ; Eggs ; Endoscopy, Digestive System ; Follow-Up Studies ; Hematologic Tests ; Hemorrhage* ; Hookworm Infections* ; Humans ; Intestine, Small ; Iron ; Necator americanus ; Ovum