Isotopic labelling applied to the infrared spectra of metal complexes

The infrared spectra of pyridine adducts of first transition series metal(II) acetylacetonates are discussed in relation to the band shifts induced by ¹⁵N-labelling and deuteration of the pyridine ring and by metal ion substitution. ¹⁵N-Labelling aids in establishing the pyridine ring vibrations, while deuteration and metal substitution are more useful in assigning the νM-L frequencies. Results of the isotopic labelling study lead to a revision of previously-reported νM-O and vC---O frequencies. This technique also facilitates assignment of the νM-N vibrations, observed in the region below 200 cm⁻¹. The occurrence of these bands in this spectral region was expected because of the known relative weakness of the M-N bond strength in pyridine adducts. The effects on the spectra resulting from introduction of a variety of substituents into the pyridine ring are discussed on the basis of the electronic effects of the substituents. After allowing for mass effects, electron-withdrawing substituents are found to decrease νNi-N frequencies while electron-releasing substituents exert negligible effect on the νNi-N bands. An opposite trend is, however, observed for the νNi-O bands and is explained. An investigation of a series of aniline and p-toluidine complexes of first transition metal(II) isothiocyanates is reported

Intravenous thrombolysis in stroke patients of ≥80 versus <80 years of age—a systematic review across cohort studies

Objective: elderly stroke patients were excluded or underrepresented in the randomised controlled trials of intravenous thrombolysis with recombinant tissue plasminogen activator (rtPA) applied within 3 h. Cohort studies comparing intravenous rtPA in stroke patients of ≥80 versus <80 years of age were limited by small sample sizes and yielded conflicting results. Thus, we performed a systematic review across all such studies. Methods: a systematic literature search (PubMed; Science Citation Index) was performed to retrieve all eligible studies. Two reviewers independently extracted data on ‘death', ‘favourable 3-month outcome (modified Rankin Scale ≤1)' and ‘symptomatic intracranial haemorrhage (sICH)'. Across studies, weighted odds ratios (ORs) with 95% confidence intervals (95% CI) were calculated. Results: six studies were included [n = 2,244 patients; 477 (21%) aged ≥80 years]. Significant differences in baseline characteristics to the disadvantage of older patients were present in all studies. Compared with younger patients, older patients had a 3.09-time (95% CI = 2.37-4.03; P < 0.001) higher 3-month mortality and were less likely to regain a ‘favourable outcome' (OR = 0.53; 95% CI = 0.42-0.66; P<0.001). The likelihood for ‘sICH' (OR = 1.22; 95% CI = 0.77-1.94; P = 0.34) was similar in both age groups. Conclusion: intravenous rtPA-treated stroke patients of ≥80 years of age have a less favourable outcome than younger ones. Imbalances in predictive baseline variables to the disadvantage of the older patients may contribute to this finding. Compared with the younger cohort, rtPA-treated stroke patients aged ≥80 years do not seem exceedingly prone to sICH. Thus, there is scope for benefit from thrombolysis for the older age group. Hence, to obtain reliable evidence on the balance of risk and benefit of intravenous rtPA for stroke patients aged ≥80 years, it is safe and reasonable to include such patients in randomised placebo-controlled trial

Diffusion weighted imaging, apparent diffusion coefficient maps and stroke etiology

Objective : In acute ischemic stroke, the number and distribution of lesions on diffusion weighted imaging (DWI) have been shown to give clues to the underlying pathogenetic mechanisms. The objective of this study was to determine whether lesion features on DWI differ between stroke due to large artery atherosclerosis (LAA) and cardioembolism (CE), and to assess the role of apparent diffusion coefficient maps (ADC). Methods : We retrospectively studied 83 consecutive patients with stroke caused by either LAA (n = 40) or cardioembolism (n = 43). DWI lesions were characterized by number, size, distribution (i. e. lesion pattern) and signal intensity on ADC maps. In part A, all hyperintense DWI lesions regardless of their ADC were compared. In part B, only hyperintense DWI lesions with hypointense appearance on ADC maps (i. e. acute lesions) were assessed. Results : Part A: The frequency of multiple hyperintense DWI lesions (LAA: 28/40, CE: 21/43; p 1 circulation (i. e. anterior plus posterior or bilateral anterior circulations) was present in 5 LAA-patients (13 %) and 4 CE-patients (9 %). Lesion size did not differ between LAA-stroke (35.1 ± 33.7 mm) and CE-stroke (35.4 ± 27.8 mm). Part B: Multiple hyperintense DWI lesions with low ADC occurred in 23/40 LAA-patients and in 15/43 CE-patients (p 1 circulation occurred only in CE-stroke (n = 3; 7%) and never in LAA-stroke. Conclusions : (1) Multiple ischemic lesions occur significantly more often in LAA-stroke than in CE-stroke. (2) ADC maps are important in the comparison of DWI lesion patterns; DWI lesions in > 1 circulation can only be assigned to a cardioembolic etiology if they appear hypointense on ADC map

Gene Expression Suggests Spontaneously Hypertensive Rats May Have Altered Metabolism and Reduced Hypoxic Tolerance

Cerebral small vessel disease (SVD) is an important cause of stroke, cognitive decline and vascular dementia (VaD). It is associated with diffuse white matter abnormalities and small deep cerebral ischemic infarcts. The molecular mechanisms involved in the development and progression of SVD are unclear. As hypertension is a major risk factor for developing SVD, Spontaneously Hypertensive Rats (SHR) are considered an appropriate experimental model for SVD. Prior work suggested an imbalance between the number of blood microvessels and astrocytes at the level of the neurovascular unit in 2-month-old SHR, leading to neuronal hypoxia in the brain of 9-month-old animals. To identify genes and pathways involved in the development of SVD, we compared the gene expression profile in the cortex of 2 and 9-month-old of SHR with age-matched normotensive Wistar Kyoto (WKY) rats using microarray-based technology. The results revealed significant differences in expression of genes involved in energy and lipid metabolisms, mitochondrial functions, oxidative stress and ischemic responses between both groups. These results strongly suggest that SHR suffer from chronic hypoxia, and therefore are unable to tolerate ischemia-like conditions, and are more vulnerable to high-energy needs than WKY. This molecular analysis gives new insights about pathways accounting for the development of SVD

Incidence of first-ever ischemic stroke in the Canton Basle-City, Switzerland: A population-based study 2002/2003

Our study sought to estimate the incidence rate of firstever ischemic stroke (FEIS) in the geographically well-defined population of the Canton Basle-City, Switzerland. An one-year prospective population-based study among the permanent residents of the Canton Basle-City (188015 inhabitants, census 2002) was carried out. Multiple overlapping sources of information were used. Stroke was defined according to the WHO criteria. The diagnosis of FEIS was based on clinical assessment and neuroimaging findings. 269 patients (114 males; mean age 72.8, standard deviation (SD) ± 12 and 155 females; mean age 78.4, SD ± 11) with FEIS were identified. The overall crude incidence of FEIS amounted to 143 per 100000 population (95% confidence interval (CI) 126 to 160) and it was higher among females (156; 95% CI 132 to 181) than in males (128; 95% CI 105 to 152). The age-specific incidence rates of FEIS approximately doubled with each decade of life, increasing from 17 (95 % CI 2 to 31) among 0-44 years old group to 1034 (95% CI 774 to 1293) for those aged 85 or more years. The overall incidence rate of FEIS adjusted for age to the European standard population was 76 per 100000 inhabitants (95% CI 66 to 86) and it was higher in males—89, 95% CI 72-106—than in females—66, 95 % CI 53-77. Moreover, in comparison with studies from other developed countries (e. g. Germany, Italy, Australia)—carried out in the middle of 1990s—the standardised incidence rates of FEIS were substantially lower in Switzerland. Our results indicate that the risk of ischemic stroke might be low in Switzerland. However, giving a major reduction in the age and gender specific stroke incidence over the past years our findings might—alternatively—mirror this favourable tren

Life-threatening orolingual angioedema during thrombolysis in acute ischemic stroke

Background: Orolingual angioedema can occur during thrombolysis with alteplase in stroke patients. However, data about its frequency, severity and the significance of concurrent use of angiotensin-converting-enzyme inhibitors (ACEi) are sparse. Objective: (1), to alert to the potentially life-threatening complication of orolingual angioedema. (2), to present CT-scans of the tongue which exclude lingual hematoma. (3), to estimate the frequency of orolingual angioedema. (4), to evaluate the risk associated with the concurrent use of ACEi. Methods: Single center, databank-based observational study on 120 consecutive patients with i. v. alteplase for acute stroke. Meta-analysis of all stroke studies on alteplase-associated angioedema, which provided detailed information about the use of ACEinhibitors. Across studies, the Peto odds ratio of orolingual angioedema for "concurrent use of ACEi" was calculated. Results: Orolingual angioedema occurred in 2 of 120 patients (1.7%, 95% CI 0.2-5.9 %).Angioedema was mild in one, but rapidly progressive in another patient. Impending asphyxia prompted immediate intubation. CT showed orolingual swelling but no bleeding. One of 19 (5%) patients taking ACEi had orolingual angioedema, compared to 1 of 101 (1%) patients without ACEi. Medline search identified one further study about the occurrence of alteplase-associated angioedema in stroke patients stratified to the use of ACEi. Peto odds ratio of 37 (95 % CI 8-171) indicated an increased risk of alteplasetriggered angioedema for patients with ACEi (p <0.001). Conclusion: Orolingual angioedema is a potentially life-threatening complication of alteplase treatment in stroke patients, especially in those with ACEi. Orolingual hematoma as differential diagnosis can be excluded by CT-sca

Bis(N-triisopropyl­silyl­quinolin-8-aminato)nickel(II)

The reddish-brown title complex, [Ni(C18H27N2Si)2], was prepared via the salt-metathesis reaction of N-triisopropyl­silyl-8-amido­quinoline lithium with nickelocene (NiCp2). The asymmetric unit contains two symmetry-independent mol­ecules with the Ni atoms in distorted tetra­hedral environments