Alterations in the proportions of skeletal muscle proteins following a unilateral lesion to the substantia nigra pars compacta of rats.

It is well established that mammalian skeletal muscles exhibit a considerable degree of plasticity and one of the main determining factors of this plasticity is the activity pattern and duration of motoneurone discharge. Lesions to the right substantia nigra pars compacta (SNpc) of six adult rats were made to determine whether altered output from the SNpc ultimately leads to a change in the expression of proteins in contralateral skeletal muscles. After 4 months, altered motor performance was identified by the administration of amphetamine. After 7 months, 30-70% of dopaminergic cells in the SNpc had been destroyed. The protein content of muscles was then quantified from densitometric scans of gels, and expressed as a % of the amount of actin (the protein used as a reference in this study). The lesion affected the expression of different protein isoforms in the fast- and slow-twitch muscles. In slow-twitch soleus muscles, the lesion decreased the proportion of alpha-tropomyosin and increased the proportion of beta-tropomyosin. In the fast-twitch extensor digitorum longus muscles, the lesion increased the proportion of the fast isoform of troponin-T1f, and decreased the proportions of the two isoforms of myosin light chain. This study establishes a connection between the chronic effects of a lesion to the SNpc, with a loss of dopaminergic neurones, impaired motor performance, and altered expression of proteins in skeletal muscle. The implication of these results is that the altered motor function observed in Parkinson's disease may be associated with alterations to the expression of skeletal muscle proteins.

Pregnenolone sulfate enhances long-term potentiation in CA1 in rat hippocampus slices through the modulation of N-methyl-D-aspartate receptors.

Among the different steroids found in the brain, pregnenolone sulfate (3beta-hydroxy-5-pregnen-20-one-3-sulfate; PREGS) is known to enhance hippocampal-associated memory. The present study employs rat hippocampal slices to investigate the ability of PREGS to modulate long-term potentiation (LTP), a phenomenon considered as a model of synaptic plasticity related to memory processes. LTP (3 x 100 Hz/1 sec within 2 min), implicated essentially glutamatergic transmission, for which the different synaptic events could be pharmacologically dissociated. We show that PREGS enhances LTP in CA1 pyramidal neurons at nanomolar concentrations and exhibits a bell-shaped concentration-response curve. The maximal effect of PREGS on both induction and maintenance phases of LTP is observed at 300 nM and requires 10 min of superfusion. Although PREGS does not change the N-methyl-D-aspartate (NMDA) component of the field potentials (fEPSPs) isolated in the presence of 10 microM 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) in Mg2+-free artificial cerebrospinal fluid, PREGS does enhance the response induced by NMDA application (50 microM, 20 sec). PREGS does not modify the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) component of the fEPSPs isolated in the presence of 100 microM DL-2-amino-7-phosphopentanoic acid (DL-AP5) or its potentiation induced by a single tetanic stimulation and the response induced by AMPA application (10 microM, 10 sec). Furthermore, PREGS does not affect the recurrent inhibition of the fEPSPs mediated by gamma-aminobutyric acid type A (GABA(A)) receptor. In conclusion, this study shows the ability of PREGS to enhance LTP in CA1 by accentuating the activity of NMDA receptors. This modulation of LTP might mediate the steroid-induced enhancement of memory.

On the polarization of light diffracted by ultrasound

If light is diffracted by ultrasound in an isotropic medium with acoustically induced birefringence, the state of polarization is modified in each order of diffraction with respect to the initial state of polarization of the incident light wave. In the present paper, some polarization effects are discussed in the case of normal light incidence. In general a rotation of the main polarization plane occurs, together with a change of the ellipticity. However, while the former effect always takes place, the latter only occurs in the case of ultrasonic light diffraction of the intermediate type. Some experimental measurements are included in case of argon laser light being diffracted by an ultrasonic wave propagating in fused silica (SiO2).

C-reactive protein: a marker for disease activity in ankylosing spondylitis and Reiter's syndrome.

Forty-four patients, 22 with ankylosing spondylitis (AS) and 22 with Reiter's syndrome (RS) were studied to determine the reliability of C-reactive protein (CRP) levels and erythrocyte sedimentation rate (ESR) as indicators of disease activity. CRP levels were significantly elevated in patients with active disease for both AS and RS while ESR values for active and inactive disease were not statistically different. Misdiagnosis was more likely when ESR rather than CRP was used as the variable for activity. CRP as measured by nephelometry is a more sensitive and specific indicator of disease activity in AS and RS than ESR.

Ankylosing spondylitis and systemic lupus erythematosus: a rare HLA combination.

The condition of a 43-year-old man fulfilled the strict diagnostic criteria for both ankylosing spondylitis and systemic lupus erythematosus. To our knowledge, this is the fist verified report of the concurrence of these rheumatic diseases. An unusual combination of genetically determined markers seems to have caused an increased risk for the development of both disorders.

Gold suppression of human neutrophil function in vitro.

The effect of myochrysine and Auranofin on leukocyte function were measured using quantitative leukocyte iodination. Both suppressed iodination at concentrations achieved in patients. Under conditions of leukocyte submaximum stimulation, enhanced gold suppression was observed. The active portion of Myochrysine appeared to be protein bound while the active portion of Auranofin appeared to be free. Preincubation experiments indicated suppression of the myeloperoxidase-halide system. Inhibition of this probable mediator of inflammation may be one of the modes of action of gold.

Experimental lens-induced granulomatous endophthalmitis in common laboratory animals.

Guinea pigs and mice after immunization with lens proteins were observed to develop a typical form of experimental phacoanaphylactic endophthalmitis after lens injury. Sensitization to lens protein elicited a good antibody response in rabbits, however no disease developed after lens injury. This is another example of frequent discrepancies between autoimmune responses and autoimmune disease and indicates the importance of investigating mechanisms of phlogogenicity in autoimmune disease.

A modification of the Detter and Klingmüller's method for urinary alpha- and beta-pregnanediol and pregnanetriol determination: excretion patterns in men and in women during the normal menstrual cycle.

This report describes the modification of Detter and Klingmüller's method for the determination of urinary alpha- and beta-pregnanediol and pregnanetriol by means of thin -layer chromatography. The modifications were as follows: 1. The addition of formol prior to hydrolysis to prevent pigments penetration into urinary extracts. 2. The use of Kieselgel HF 254+366 nach Stahl (E. Merck, Darmstadt) which allows to localize the spots under UV-light at 366 nm without the use of colour reagents. The results concerning accuracy, sensitivity, precision and specificity in the modification described are profitable. Using this method in 7 healthy women (aged 28-37) with normal menstrual cycles the urinary excretion of alpha- and beta-pregnanediol and pregnanetriol were evaluated every second day (starting the 6th day of the cycle). The maximum of excretion of alpha- and beta-pregnandiol appeared on day 20 of the cycle, with the mean (+/- S.D.) 1.27 +/- 0.37 mg/24hr and 2.97 +/- 0.80 mg/24hr for alpha- and beta-pregnanediol, respectively. Mean values of pregnantriol were at the same level and ranged from 0.25 to 1.42 mg/24 hr. Single determination of these compounds in 8 healthy men (aged 19-42) revealed the mean excretion values (+/- S.D.) 0.96 +/- 0.17 mg/24 hr, 1.24 +/- 0.40 mg/24 hr, 1.12 +/- 0.65 mg/24 hr for alpha- and beta-pregnanediol and pregnanetriol, respectively.