Low-temperature sample orienting device with two degrees of freedom

We describe a rotating sample holder with two degrees of freedom for galvanomagnetic measurements at low temperatures which allows positioning within 0.5 degrees with a reproducibility of better than 0.5 degrees . The main advantages of our device over other constructions are simple and accurate device adjustment, simple and convenient handling, and simple and quick sample changing.

Echolocation performance of the vampire bat (Desmodus rotundus)

The neotropical vampire bats (Desmodus rotundus) echolocate using ultrasonic pulses like those of the Latin American phyllostomatid bats. In this paper the orally produced echolocation sounds of Desmodus are analysed and the performance of the echolocation system is studied in two-choice training experiments on two vampire bats. Ability to detect objects is relatively limited; both animals were capable of discerning the presence of a 1 cm wide metal strip at a distance of 50 cm, but they failed with 0.5 cm wide strips. The ultrasonic pulses produced at a distance of 50 cm appear to sample an area with a diameter of 2.5 to 3.0 cm (i.e., the solid angle tested with each pulse is 3 degrees to 3 degrees 40' in extent).

Positive feedback of oestrogen on LH secretion in women in neuroleptic drugs

The effect of a-adrenergic and dopaminergic blockade on the ability of pituitary-hypothalamic axis to produce an LH surge in response to oestrogen, was studied in eleven women treated with the neuroleptic agents haloperidol, fluphenazine or chlorpromazine. Seven women on no medication were controls. 6.6 mg of oestradiol benzoate (OB) was injected i.m. after control serum was obtained and daily serum samples were obtained for four additional days. Sera were assayed for total oestrogens, LH, FSH and prolactin. Six of seven women in the control group and eight of eleven women treated with neuroleptic agents had LH surges to OB challenge. The mean prolactin of the treated women was 33.1 +/- 3.6(SEM) ng/ml and the mean prolactin of the controls was 14.9 +/- 1.5(SEM) ng/ml, P less than 0.005). Elevated levels of circulating prolactin did not prevent an LH surge to OB challenge. These results indicate that even in subjects with catecholamine blockade, an LH surge can be induced. This contrasts to results obtained in rats and suggests that the control mechanism of LH surge production differs in rodents and humans.

Cholestrol and cholesteryl ester content in normal and pathologic scale

Using a sensitive new assay, we have measured the cholesteryl ester and cholesterol contents of stratum corneum from callus, normal skin, psoriatic lesions (plantar and nonplantar), and lamellar ichthyotic lesions (plantar and nonplantar). Cholesteryl ester content of normal stratum corneum was significantly higher than that of callus, suggesting that callus was not a suitable control tissue for further biochemical studies involving sterol content of stratum corneum. Both psoriatic and lamellar ichthyotic scale have increased levels of free cholesterol and decreased levels of esterified cholesterol when compared to appropriate controls.

[Landouzy-Dejerine syndrome. Evolution of the concept of facio-scapulo-humeral amyotrophia]

Detailed analysis of the literature and the study of personal cases have led the authors to propose a new concept for facio-scapulo-humeral dystrophy. They consider it to be a syndrome, embracing under the same clinical picture both muscular disease (classical hereditary muscular dystrophy, congenital and acquired myopathies) and neurological disease (in particular progressive pseudomyopathic amyotrophy).

[Nosographic approach of heriditary myopathies. Attempt at classification and diagnosis by means of erythrocyte cholinesterase and serum pseudocholinesterase analysis]

An original biological study involving assessment of red cell cholinesterase and serum pseudo-cholinesterase activity has given the authors a new approach to the classification of progressive muscular dystrophy: as a result, it has become possible to isolate Duchenne dystrophy and the carries of this disease and to distinguish them from cases of Becker's disease. Also, Leyden-Möbius dystrophy appears to deserve the name as it differs from limb-girdle dystrophy. Finally, there is a case to be made for classifying separately, because of its special biological characteristics, Steinert's myotonic dystrophy.

Contractile responses to epinephrine, serotonin, and potassium in arterial smooth muscle

Effects of epinephrine, serotonin, and KCl on development of isometric tension were studied in strips of rat femoral and tail artery smooth muscle. Strkining differences were detected between the preparations. Tension development in tail artery smooth muscle was greatest with epinephrine, intermediate with serotonin, and least with K+. In femoral preparations tension developed was greatest with serotonin. Smaller but comparable contractions were elicited with epinephrine and K+. Theoretical and experimental dose-response curves for epinephrine and serotonin agreed closely, whereas curves for K+ differed markedly. The relationship between fractional response and fractional stimulus was hyperbolic for epinephrine and serotonin but sigmoid for K+. The Hill coefficient for serotonin was about 1, slightly smaller than 1 for epinephrine (0.5 to 0.8) and significantly greater for K+ (5 to 5). These findings show that responses elicited with either epinephrine or serotonin are mechanistically consistent with receptor occupancy theory. They suggest that specific receptors for K+ exist and that they may involve positive cooperative interactions similar those described for receptor mechanisms in electroplax.

Contractile responses to angiotensin I and angiotensin II in hamster uterine smooth muscle

Angiotensin I (A-I) and angiotensin II (A-II) produced dose-dependent increases in isometric tension in isolated strips of uterine smooth muscle prepared from ovariectomized golden hamsters treated with estrogen. Responses to A-II were consistent with receptor--occupancy theory of agonist--receptor interactions. Inhibition of angiotensin-converting enzyme virtually abolished responses to A-I but not those to A-II. Blockade of A-II receptors inhibited responses to both A-I and A-II. Cholinergic or alpha-adrenergic blockade did not alter uterine responses to either A-I or A-II. These findings suggest that contractile responses elicited in the isolated uterus of the hamster are due to its local conversion to A-II and subsequent interactions with specific A-II receptors. Such conversion occurs at least to the extent of 14 to 27 %.

[Hansen's neuritis in the form of pseudysyringomyelia. Clinical, diagnostic and therapeutic consideration a propos of 3 cases]

Three cases of neuropathic leprosy (one Moroccan, two non-colonial immigrants) enable attention to be drawn to two aspects of theproblem of Hansen's neuritis: 1) such cases should no longer be considered exceptional, infection occuring in countries where leprosy is endemic but the disease developing years later in any country; 2) among the various neurological aspects of neuritis due to Hansen's bacillus, great stress is laid on sensory disorders of the syringomyelic type, with thermalgesic dissociation; although these symptoms have been considered typical (our three cases are an illustration of this), they seem to occur fairly rarely and are the cause of difficulties in diagnosis as it is the last thing one would think of. Treatment of these neural forms is not encouraging, in spite of a therapeutic arsenal which in theory is considered effective.

[Current aspects of the myotonic syndromes]

On the basis of a clinical and physiological definition of the myotonic syndrome, the author define the scope of their research in two directions: a) the true myotonic syndromes, b) the related syndromes. Amongst the former, two entities are studied from the point of view of the recent discoveries in the field : Thomsen's disease, with some new anatomopathological and genetic considerations; Steinert's disease, concerning which there is much more new evidence in regard to clinical findings (ocular, endocrine, digestive, nervous and, in particular, cardiac symptoms) as well as biological and morphological tests. The genetic aspects are of great interest, for they lead to practical applications in genetic counselling (linkage). A brief therapeutic survey follows. Amongst the related syndromes, the best known is Eulenburg's congenital paramyotonia, the main characteristics of which are briefly described.