The vibrational spectrum of hydrogen peroxide, released from an urea hydrogen peroxide adduct compound, is studied in Ar, Kr, and Xe matrices. The gaseous products of the thermal decomposition of urea hydrogen peroxide in an argon atmosphere are determined using a low-resolution fast scanning FTIR−gas analyzer. Upon the solid sample being warmed to temperatures of ∼90 °C, only hydrogen peroxide is detected, and above that, NH3 and HNCO are evolved due to the decomposition of urea. The hydrogen peroxide−rare gas matrices are prepared from urea hydrogen peroxide by sweeping Ar, Kr, or Xe gas over the solid sample kept at a suitable temperature. The ratio between trapped monomer and multimers can be controlled by varying the amount and the temperature of the sample and the gas flow rate. The results show that urea hydrogen peroxide is a convenient source of pure hydrogen peroxide for spectroscopic studies. The IR spectra of H2O2, HDO2, and D2O2 in argon matrices are presented and compared with previous results. The krypton and xenon spectra are presented for the first time. Many of the peaks show a well-resolved doublet structure.

In cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) the vascular smooth muscle cells are destroyed and granular osmiophilic material is deposited followed by fibrosis of the arterial wall. To verify whether true stenosis of the fibrotic white matter arteries is a key pathogenic event in CADASIL, we analyzed the thickness of walls (expressed as sclerotic index) and luminal diameters of penetrating arterioles in both grey matter and white matter of four CADASIL patients due to the C475T (R133C) mutation in the Notch3 gene and in 9 age-matched controls. We also reconstructed 9 arterioles from 1000 serial sections in two CADASIL patients. The thickness of the arteriolar walls in both grey matter and white matter was significantly increased in the CADASIL patients compared with controls. Furthermore, in CADASIL patients the arteriolar walls were significantly thicker in the white matter than in the grey matter. The distribution curve of arteriolar internal diameters in CADASIL patients shifted towards smaller sizes. In serial sections, the marked increase in the thickness of the white matter penetrating arterioles or their branches did not occur until the internal diameters had decreased to about 20 to 30 pm and external diameters to about 100 to 130 microm. In conclusion, long penetrating arterioles and their branches supplying subcortical structures in CADASIL are stenosed and their walls are thickened. This conforms to the abundance of infarcts and primary ischemic damage in CADASIL patients' white matter.

Background and Purpose-Cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) causes repeated ischemic attacks leading to subcortical vascular dementia. The aim of this study was to characterize cognitive function in subjects with a C475T (R133C) mutation in the Notch3 gene, leading to CADASIL. Methods-Prestroke (nϭ13) and poststroke (nϭ13) mutation carriers and mutation carriers with dementia (nϭ8) were compared with healthy noncarriers from the same families using a comprehensive set of neuropsychological tests. Results-Changes in working memory and executive function were observed in the very early phase of the disease before transient ischemic attack (TIA) or stroke. Later, in the poststroke phase, the cognitive impairment concerned also mental speed and visuospatial ability. Finally, the subjects with dementia had multiple cognitive deficits, which engaged even verbal functions, verbal episodic memory, and motor speed. The 2 mutation carrier groups without dementia and the controls could be reliably distinguished using 3 tests that assessed working memory/attention, executive function, and mental speed. Episodic memory was relatively well-preserved late in the disease. Conclusion-A deterioration of working memory and executive function was already observed in the prestroke phase, which means that cognitive decline may start insidiously before the first onset of symptomatic ischemic episodes.