Tremor and senile parkinsonism.

A study of 100 Day Hospital patients showed that 26 elderly patients with mild Senile Parkinsonism and varying degrees of dementia had subclinical tremor with the same frequency as Parkinson's Disease and distinguishable by amplified recordings from those of Parkinson's Disease and Senile Tremor. A significant history of cerebro-vascular disease was obtained in one-half of these patients. The recording of tremor is shown to be of value in diagnosing Parkinsonism and in assessing response to treatment.

Progressive systemic sclerosis in the elderly.

There is evidence to suggest that the incidence of progressive systemic sclerosis in the elderly is more common than in younger age groups. As in younger patients, late onset cases may have minimal skin changes and this can cause difficulty in diagnosis. The case histories of 2 patients are presented to illustrate these points.

Progressive supranuclear palsy.

In the past four years, four patients with progressive supranuclear palsy have presented to the Department of Geriatric Medicine, Oxford, under the care of one of us (RAG). They were all females whose symptoms began in the sixth or seventh decade. They died from three to six years after the onset of symptoms. All had neuropathological studies which are described. The presenting characteristics included frequent falls, difficulty in walking, nuchal rigidity, abnormalities of gaze, pseudobulbar features and mild dementia. These are features particularly common in the elderly and it is suggested that the condition may be under-diagnosed.

Cathodic stripping voltammetry of nanogram amounts of selenium in biological material.

A method is described to determine selenium in biological material, based on cathodic stripping voltammetry. Following wet ashing, the selenium was extracted into benzene as the 3',4'-diaminophenylpiazselenol. The selenium was subsequently back-extracted into dilute acid for analysis. Analyses of NBS Bovine Liver demonstrated that the method was capable of recovering 96+/-9% of the selenium present. The detection limit and working range were 3 ng/g and 0-10,000 ng/g, respectively. The method was also applied to the determination of selenium in rapeseed oils and seed.

The acid dissociation constants of 2,3-quinoxalinedithiol.

Sodium salts of 2,3-quinoxalinedithiol have been prepared and used for determination of the acid ionization constants by potentiometric titration. The fully protonated form of the reagent was used in an alternative determination of the first ionization constant by a solubility method. The constants are pK(2), == 6.84 +/- 0.04 and pK(2) = 9.95 +/- 0.03.

Spectrophotometric determination of palladium by reaction with tin(II) in binary halide mixtures.

The coloured complexes produced in the systems Pd(II): Sn(II):X:X', where X and X' are different halide ions, have been studied. In bromide/iodide mixtures, palladium(II) reacts with tin(II) species in acidic ethanol media to form a deep purple complex with maximum absorption at 555 nm. This is the basis of a rapid and sensitive spectrophotometric method for the determination of palladium. The complex is stable in the absence of air, but water interferes and must not be present in amounts more than 15% of the total volume of the ethanolic mixture.

Gravimetric determination of nickel with quinoxaline-2,3-dithiol by precipitation from homogeneous solution.

The investigation of quinoxaline-2,3-dithiol as a gravimetric reagent for nickel is described. A derivative of the dithiol, S-2-(3-mercaptoquinoxalinyl)thiuronium chloride is used as a generating agent in a PFHS method because of its relative stability and solubility in aqueous ethanol. Nickel, 2.5-25.0 mug, can be precipitated at pH 2-3 as (C(8)H(5)N(2)S(2))(2)Ni. After filtration the precipitates are washed first with aqueous ethanol to remove traces of absorbed reagent and then with benzene to remove a small amount of decomposition product of the reagent, the characterization of which is described. The precipitates are stable and can be dried in air at 110-120 degrees . Errors of less than 0.15 % are obtained in the analysis of solutions containing 25 mg of nickel. The selectivity of the reagent is discussed and some suggestions are made for masking the interference of other elements.

Improved method for the simultaneous absorptiometric determination of cobalt and nickel with quinoxaline-2,3-dithiol.

A new, more stable reagent, S-2-(3-mercaptoquinoxalinyl)thiuronium chloride (MQT), is proposed for the simultaneous absorptiometric determination of cobalt and nickel. It is hydrolysed rapidly to quinoxaline-2,3-dithiol (QDT) in ammonia buffer at pH 10. In the presence of zinc(II), QDT is stabilized by complex formation and the reagent blanks are reduced. Samples containing cobalt(II) and nickel(II) react with the mixture on warming to give 1:3 cobalt and 1:2 nickel complexes, with maximum absorbances at 472 and 520 mmu respectively. The sensitivity of the method is high, 0.0017 and 0.0028 mug cm (2) for cobalt and nickel respectively, and there is a significant improvement in accuracy and precision, which is about +/-1 % over a 15-fold change in cobalt to nickel ratio. The selectivity is moderate; Ag(I), Cu(II), Pd(II), Cd(II), Hg(II), Sn(II), Pb(II), Bi(III) and Pt(IV) cause significant interference but most other common cations and anions can be tolerated.