Glass transition temperature of dried lens tissue pretreated with trehalose, maltose, or cyclic tetrasaccharide

[PURPOSE] Glass transition temperature is a main indicator for amorphous polymers and biological macromolecules as materials, and would be a key for understanding the role of trehalose in protecting proteins and cells against desiccation. In this study, we measured the glass transition temperature by differential scanning calorimetry of dried lens tissues as a model of a whole biological tissue to know the effect of pretreatment by trehalose and other sugars. [METHODS] Isolated porcine lenses were incubated with saline, 100 or 1000 mM concentration of trehalose, maltose, or cyclic tetrasaccharide dissolved in saline at room temperature for 150 minutes. The solutions were removed and all samples were dried at room temperature in a desiccator until no weight change. The dried tissues were ground into powder and placed in a measuring pan for differential scanning calorimetry. [RESULTS] The glass transition temperature of the dried lens tissues, as a mean and standard deviation, was 63.0 ± 6.4°C (n = 3) with saline pretreatment; 53.0 ± 0.8°C and 56.3 ± 2.7°C (n = 3), respectively, with 100 and 1000 mM trehalose pretreatment; 56.0 ± 1.6°C and 55.8 ± 1.1°C (n = 3), respectively, with 100 and 1000 mM maltose pretreatment; 60.0 ± 8.8°C and 59.2 ± 6.3°C (n = 3), respectively, with 100 and 1000 mM cyclic tetrasaccharide pretreatment. The glass transition temperature appeared lower, although not significantly, with trehalose and maltose pretreatments than with saline and cyclic tetrasaccharide pretreatments (P > 0.05, Kruskal-Wallis test). The glass transition temperature of the dried lens tissues with trehalose pretreatment appeared more noticeable on the thermogram, compared with other pretreatments. [CONCLUSIONS] The glass transition temperature was measured for the first time in the dried lens tissues as an example of a whole biological tissue and might provide a basis for tissue preservation in the dried condition

POEMS Syndrome in a 20-year-old Patient Diagnosed Following a Complaint of Reduced Visual Acuity

We report a case of POEMS syndrome in a 20-year-old patient diagnosed after visiting an eye clinic with a chief complaint of reduced visual acuity. A male university student aged 20 years was referred to our department complaining of blurred vision in both eyes that had persisted for 1 month. He also noted headache, nausea, and paresthesia in the lower extremities around the same time. The visual acuity of his right and left eye was 20/40 and 20/20, respectively. Optic disc edema and serous retinal detachment were present. Brain magnetic resonance imaging showed no intracranial abnormalities, while elevated cerebrospinal fluid pressure, reduced nerve conduction velocity in both lower extremities, hepatosplenomegaly, M proteinemia, high blood VEGF levels, osteoblastic and osteolytic changes in the spine, and atypical plasma cells in bone lesions were noted. From the above findings, the patient was diagnosed with POEMS syndrome. He received high-dose dexamethasone, thalidomide, and radiotherapy on the sacral mass, followed by high-dose melphalan with autologous stem-cell support, and showed subsequent systemic and ophthalmologic improvement. Here, we report the youngest case ever of POEMS syndrome with ocular manifestation. If patients have optic disc edema in both eyes with no intracranial space-occupying lesion, POEMS syndrome should be considered in differential diagnosis, regardless of age