Evolutionary insights into sequence modifications governing chitin recognition and chitinase inactivity in YKL-40 (HC-gp39, CHI3L1).

YKL-40, also known as human cartilage glycoprotein-39 (HC-gp39) or CHI3L1, shares structural similarities with chitotriosidase (CHIT1), an active chitinase, but lacks chitinase activity. Despite being a biomarker for inflammatory disorders and cancer, the reasons for YKL-40's inert chitinase function have remained elusive. This study reveals that the loss of chitinase activity in YKL-40 has risen from multiple sequence modifications influencing its chitin affinity. Contrary to the common belief associating the lack of chitinase activity with amino acid substitutions in the catalytic motif, attempts to activate YKL-40 by creating two amino acid mutations in the catalytic motif (MT-YKL-40) proved ineffective. Subsequent exploration that included creating chimeras of MT-YKL-40 and CHIT1 catalytic domains (CatDs) identified key exons responsible for YKL-40 inactivation. Introducing YKL-40 exons 3, 6, or 8 into CHIT1 CatD resulted in chitinase inactivation. Conversely, incorporating CHIT1 exons 3, 6, and 8 into MT-YKL-40 led to its activation. Our recombinant proteins exhibited properly formed disulfide bonds, affirming a defined structure in active molecules. Biochemical and evolutionary analysis indicated that the reduced chitinase activity of MT-YKL-40 correlates with specific amino acids in exon 3. M61I and T69W substitutions in CHIT1 CatD diminished chitinase activity and increased chitin binding. Conversely, substituting I61 with M and W69 with T in MT-YKL-40 triggered chitinase activity while reducing the chitin-binding activity. Thus, W69 plays a crucial role in a unique subsite within YKL-40. These findings emphasize that YKL-40, though retaining the structural framework of a mammalian chitinase, has evolved to recognize chitin while surrendering chitinase activity.

Prospective Study of Engagement in Leisure Activities and All-Cause Mortality Among Older Japanese Adults.

BACKGROUND: Engagement in leisure activities among older people is associated with a lower risk of mortality. However, no studies have been conducted focusing on the difference of associations with mortality risk among multiple types of leisure activities. METHODS: We examined prospectively the association of engagement in leisure activities with all-cause mortality in a cohort of older Japanese adults. The Japan Gerontological Evaluation Study included 48,216 participants aged 65 years or older. During a mean follow-up period of 5.6 years, we observed 5,575 deaths (11.6%). We investigated the total number of leisure activities, as well as combinations of 25 different leisure activities with Cox proportional hazards models, adjusting for potential confounding factors. RESULTS: We found a linear relationship between the total number of leisure activities and mortality hazard (adjusted hazard ratio, 0.93; 95% CI, 0.92-0.95). Furthermore, engagement in leisure activities involving physical activity, as well as group-based interactions, showed the strongest associations with lowered mortality. By contrast, engagement in cultural leisure activities and solitary leisure activities were not associated with all-cause mortality. CONCLUSION: Although we cannot rule out residual confounding, our findings suggest that encouraging engagement in physically-active group-based leisure activities may promote longevity in older adults.

Image quantification technology of the heterochromatin and euchromatin region for differential diagnosis in the lobular endocervical glandular hyperplasia.

BACKGROUND: Lobular endocervical glandular hyperplasia (LEGH) was first described by Nucci et al. in 1999 and is believed to be a precancerous lesion of minimal deviation adenocarcinoma and gastric-type adenocarcinoma in the uterine cervix. LEGH lesions do not always exhibit apparent cellular and structural atypia, so are difficult to distinguish from normal endocervical cells (EC cells) with cytological examination. Therefore, we often struggle to make a definite diagnosis of LEGH. METHODS: We used microscopy images of cytological specimens that were diagnosed as EC cells and LEGH cells. Signal intensity in whole nuclear area and in heterochromatin and euchromatin regions, euchromatin area ratio, and nuclear morphological features were quantified in each cell nucleus of the cases. Statistical analyses were conducted to determine statistical significance. Finally, we performed linear support vector machine (LSVM) modeling as a discriminant analysis using the quantified features. RESULTS: Signal intensity in whole nuclear area, and heterochromatin and euchromatin regions of EC cell nuclei were higher than that of the LEGH cell nuclei. Morphologically, EC cell nuclei were larger than LEGH cell nuclei, and nuclei of LEGH cells had irregular nuclear respectively membrane structure and an elongated shape. The LSVM accuracy of 10-fold cross validation and leave-one-case-out cross-validation (LOCOCV) using all measured features were 84.7% to 89.3% and 78.6% to 86.0%, respectively. CONCLUSIONS: The LVSM analysis using features extracted from signal intensity and morphological analysis was useful for discrimination of EC cells vs LEGH cells. We therefore believe that this image analysis method could be used for early detection of LEGH.

Photocatalytic alkoxylation of benzene with 3-cyano-1-methylquinolinium ion.

One-pot alkoxylation of benzene with alcohols occurs under photoirradiation of 3-cyano-1-methylquinolinium ion in an oxygen-saturated acetonitrile solution containing benzene and alcohols. The photocatalytic reaction mechanism was clarified by nanosecond laser flash photolysis. The photocataytic alkoxylation of benzene is initiated by photoinduced electron transfer from benzene to the singlet excited state of 3-cyano-1-methylquinolinium ion, followed by the nucleophilic addition of alcohols to benzene radical cation. In the case of photoethoxylation, the optimal product and quantum yields of ethoxybenzene were 20% and 10%, respectively.

Vitreous levels of vascular endothelial growth factor in eyes with anterior hyaloidal fibrovascular proliferation.

PURPOSE: To determine the intravitreal levels of vascular endothelial growth factor (VEGF) in eyes with anterior hyaloidal fibrovascular proliferation (AHFVP). METHODS: Three eyes of three patients who underwent vitrectomy for proliferative diabetic retinopathy (PDR) and subsequently developed an AHFVP (AHFVP group) were studied. We measured the level of VEGF in vitreous samples collected at the primary and following operations by enzyme-linked immunosorbent assay. The vitreous levels of VEGF in 25 eyes of 22 patients with PDR were also studied as controls (PDR group). RESULTS: The averaged VEGF level in the samples collected at the primary surgery was 1.98 ± 2.23 ng/mL in the PDR group, and it was 9.07, 1.94, and 8.07 ng/mL in the AHFVP cases. After the primary surgery, the VEGF level rose up to 49.50, 15.60, and 50.60 ng/mL at the subsequent surgeries for respective cases of the AHFVP group. These levels of VEGF were more than five times higher than the baseline at the primary surgery. CONCLUSION: The subsequent increase of the VEGF level after the primary surgery in eyes with an AHFVP suggests that the vitreous levels of VEGF are associated with the development of the AHFVP although only three eyes were studied.

Changes of oscillatory potentials and photopic negative response in patients with early diabetic retinopathy.

PURPOSE: To investigate the clinical significance of the oscillatory potentials (OPs) and photopic negative response (PhNR) of the electroretinogram (ERG) in patients with early diabetic retinopathy. METHODS: One hundred two diabetic patients with diabetic retinopathy at different stages were examined. Thirty-two age-matched normal controls were also studied. Full-field maximal and photopic cone ERGs were recorded. The amplitudes and implicit times of the OPs, cone b wave, and PhNR were compared at the different stages of diabetic retinopathy. RESULTS: The a and b wave amplitudes of the maximal scotopic ERGs remained unchanged despite advancing stages of retinopathy, but the OP amplitudes were significantly attenuated even at an early stage of diabetic retinopathy. The amplitudes of both the PhNR and cone b wave were reduced at an early stage of diabetic retinopathy. Analysis of the receiver operating characteristic curves demonstrated that the amplitudes and implicit times of the OPs were more sensitive and specific than those of the PhNR in detecting changes of retinal function in the early stages of diabetic retinopathy. CONCLUSIONS: The amplitudes of the OPs and PhNR progressively decrease with the progression of diabetic retinopathy. The PhNR amplitudes were reduced along with the cone b wave, indicating that earlier change of the PhNR in diabetic patients reflects reduced input to the retinal ganglion cell from the distal retina. The amplitudes and implicit times of the OPs are better indicators than those of the PhNR in detecting functional decreases in patients with early diabetic retinopathy.