20 research outputs found
Tangential vitreous traction: a possible mechanism of development of cystoid macular edema in retinitis pigmentosa
We report the possible mechanism of development of cystoid macular edema (CME) in retinitis pigmentosa (RP) in the case of a 68-year-old woman with RP and CME in the right eye and resolving CME in the left eye. Spectral domain optical coherence tomography showed CME and posterior vitreoschisis in the nasal quadrant of the fundus without a posterior vitreous detachment (PVD). This vitreous pathology suggested bilateral thickening and shrinkage of the posterior vitreous cortex. In the right eye, CME was evident with no vitreofoveal separation. However, in the left eye, minimal change was seen in the CME associated with a focal shallow PVD over the fovea. The best-corrected visual acuity (BCVA) in the left eye increased to 0.3 from 0.15 7 years after the first visit. Tangential vitreous traction on the macula may have caused the CME in the right eye. The shallow PVD over the fovea might have released the tangential vitreous traction from the fovea, induced spontaneous resolution of the CME, and improved the BCVA in the left eye
Clarifying the mechanism of idiopathic macular hole development in fellow eyes using spectral-domain optical coherence tomography
A New Spontaneously Diabetic Non-obese Torii Rat Strain With Severe Ocular Complications
A new spontaneously diabetic strain of the Sprague-Dawley rat was established in 1997 and named
the SDT (Spontaneously Diabetic Torii) rat. In this
research, we investigated the characteristics of the
disease condition in the SDT rats. The time of onset
of glucosuria was different between male and
female SDT rats; glucosuria appeared at approximately
20 weeks of age in male rats and at approximately
45 weeks of age in female rats. A cumulative
incidence of diabetes of 100% was noted by 40
weeks of age in male rats, while it was only 33.3%
even by 65 weeks of age in female rats. The survival
rate up to 65 weeks of age was 92.9% in male
rats and 97.4% in female rats. Glucose intolerance
was observed in male rats from 16 weeks of age.
The clinical characteristics of the male SDT rats
were (1) hyperglycemia and hypoinsulinemia (from
25 weeks of age); (2) long-term survival without insulin
treatment; (3) hypertriglyceridemia (by 35
weeks of age); however, no obesity was noted in
any of the male rats. The histopathological characteristics
of the male rats with diabetes mellitus
(DM) were (1) fibrosis of the pancreatic islets (by
25 weeks of age); (2) cataract (by 40 weeks of age);
(3) tractional retinal detachment with fibrous proliferation
(by 70 weeks of age) and (4) massive hemorrhaging
in the anterior chamber (by 77 weeks of age).
These clinical and histopathological characteristics
of the disease in SDT rats resemble those of human
Type 2 diabetes with insulin hyposecretion. In conclusion,
SDT rat is considered to be a potentially
useful model for studies of diabetic retinopathy
encountered in humans
Induction of cell proliferation in the rat liver by the short-term administration of ethyl <i>tertiary</i>-butyl ether
The Spontaneously Diabetic Torii Rat: An Animal Model of Nonobese Type 2 Diabetes with Severe Diabetic Complications
The Spontaneously Diabetic Torii (SDT) rat is an inbred strain of Sprague-Dawley rat and recently is established as a nonobese model of type 2 diabetes (T2D). Male SDT rats show high plasma glucose levels (over 700 mg/dL) by 20 weeks. Male SDT rats show pancreatic islet histopathology, including hemorrhage in pancreatic islets and inflammatory cell infiltration with fibroblasts. Prior to the onset of diabetes, glucose intolerance with hypoinsulinemia is also observed. As a result of chronic severe hyperglycemia, the SDT rats develop profound complications. In eyes, retinopathy, cataract, and neovascular glaucoma are observed. Proliferative retinopathy, especially, resulting from retinal neovascular vessels is a unique characteristic of this model. In kidney, mesangial proliferation and nodular lesion are observed. Both peripheral neuropathy such as decreased nerve conduction velocity and thermal hypoalgesia and autonomic neuropathy such as diabetic diarrhea and voiding dysfunction have been reported. Osteoporosis is another complication characterized in SDT rat. Decreased bone density and low-turnover bone lesions are observed. Taking advantage of these features, SDT rat has been used for evaluating antidiabetic drugs and drugs/gene therapy for diabetic complications. In conclusion, the SDT rat is potentially a useful T2D model for studies on pathogenesis and treatment of diabetic complications in humans