Isolation and purification of a lethal scorpion toxin with neuromuscular blocking activity

Toxin-L a lethal neuromuscular blocking agent was isolated from the venom of the scorpion, Lychas laevifrons (Pocock), by the CM-cellulose ion-exchange chromatography. It was a homogenous, thermolabile and low molecular weight protein. The toxin produced irreversible blockade of indirect stimulation induced twitch responses on innervated rat phrenic nerve-diaphragm and chick biventer cervicis preparation. The toxin did not produce any contractile response on toad rectus abdominis muscle preparation. On chronically denervated rat diaphragm, the toxin failed to alter the responses induced by direct stimulation, exogenous acetylcholine, potassium chloride and caffeine. Acetylcholine and carbachol induced contractions on isolated chick biventer cervicis remained unaltered by the toxin. Neostigmine failed to alter toxin induced neuromuscular blockade on innervated rat diaphragm. The toxin released a significant amount of acetylcholine from innervated rat diaphragm. It may be concluded that the toxin acts presynaptically through the release of acetylcholine, thereby producing neuromuscular blockade.     

Observations on the cytology of Bipes (Amphisbaenia) with special reference to its lampbrush chromosomes

The positions and general anatomical and histological characteristics of the gonads of Bipes biporus and B. canaliculatus are described. The amounts of DNA per haploid chromosome set have been measured in both species, the values being 1.83 and 2.0 pg for biporus and canaliculatus respectively. The karyotypes of both species are described on the basis of data from mitotic and meiotic metaphase chromosome sets and from lampbrush chromosomes. B. biporus has 10 macrochromosomes and 11 microchromosomes. B. canaliculatus has 11 macrochromosomes and 11 microchromosomes. The karyotypes of the two species differ distinctly with regard to the shapes of 3 of the macrochromosomes. Chiasma distribution is described for male meiosis in B. biporus. Studies of the lampbrush chromosomes of both species show the chiasma distribution in the female to be generally similar to that found in the male biporus. In B. canaliculatus, lampbrush chromosomes with maximally extended lateral loops are found in oocytes that are oblate spheroids measuring 0.7×1.0 mm along their short and long axes respectively, these being well before the start of the major phase of vitellogenesis. Smaller oocytes have more distinct chromomeres and shorter loops. Microchromosomes take the form of typical small lampbrush chromosomes in oocytes. There are at the most 1,000 chromomeres per haploid set of lampbrush chromosomes in B. canaliculatus. Chiasmata are described from lampbrush preparations in which the two half-bivalents are firmly attached to one another without evident association of their axes, indicating the possibility of chiasmate association between the DNA axes of lateral loops. There are remarkably few extrachromosomal nucleoli in Bipes oocytes, and its is suggested that this may indicate a level of ribosomal gene amplification that is much lower than that found in fish and Amphibia. The observations are particularly discussed in relation to current ideas concerning the structure and function of lampbrush chromosomes.     

Environmental temperature and lactation (with special reference to cattle)

The majority of fundamental information on temperature effects on lactation is on cattle. The yield and composition of milk are affected by the temperature of the environment or the animal's body temperature. Environmental temperatures lower and higher than the comfort zone temperatures, diminish yield and alter many of the components of milk. Concepts as to the possible manner in which temperature may alter the synthesis of milk and the role of the neuro-endocrine and environmental physiological funtions in the maintenance of lactation were presented. The elucidation of many of these postulated mechanisms of temperature effect on lactation merely awaits the application of available modern endocrine, physiological, and biochemical techniques utilizing chromatography, tracer, fluorometric, manometric, and other procedures.

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Zusammenfassung Der Hauptteil der grundsÄtzlichen Kenntnisse über Einflüsse der Temperatur auf die Milcherzeugung betrifft Rinder. Die Milchleistung und Zusammensetzung der Milch werden von der Temperatur der Umgebung sowie im Tier beeinflusst. Temperaturen der Umgebung, die höher oder tiefer sind als die des normalen körperlichen Wohlbefindens, verringern die Michleistung und verÄndern die Zusammensetzung der Milch. Die verschiedenen Arten der VerÄnderung der Milchsynthese durch Temperaturunterschiede und die Rolle der neuro-endokrinen und anderen physiologischen Funktionen zur Unterstützung der Milcherzeugung werden dargestellt-Die AufklÄrung vieler dieser angenommenen Mechanismen des Temperatureinflusses auf die Milchproduktion verlangt lediglich die Anwendung der üblichen modernen Methoden der Hormonforschung, der Physiologie und Biochemie.

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Resume La majeure partie des recherches faites sur l'influence exercée par la température sur la lactation concerne les bovidés. La quantité et la composition du lait son influencées par la température ambiante ou par celle du corps de l'animal. Des températures extérieures supérieures ou inférieures à celles limitant la zone de confort diminuent les quantités de lait sécrété et modifient plusieurs de ses composants. On indique ici les différentes possibilités d'action de la température sur la sythèse du lait et le rÔle que jouent les fonctions physiologiques, en particulier neuroendocrines sur le maintient de la lactation. L'établissement de bien des mecanismes supposés de l'influence de la température sur la production laitière nécessite l'utilisation des techniques modernes en physiologie et en biochimie ainsi que dans la recherche des hormones. Il s'agit en particulier de la Chromatographie,de la chimie, de la mesure de la fluorescence, des mesures de pression, etc.

     

Acid phosphatase activity demonstrated by intact Angiostrongylus cantonesis with special reference to its function.

Intact Angiostrongylus cantonensis is able to hydrolyse glucose-phosphate esters, mononucleotides and rho-nitrophenyl phosphate as well as beta-glycerophosphate in vitro. Reciprocal inhibition studies suggest that the hydrolysis of such substrates is due to a non-specific phosphomonoesterase. Molybdate ions, which exert no effect on either the uptake of glucose or the production of lactate, inhibit the hydrolysis of glucose-1-phosphate in the external medium and simultaneously lower the production of lactate by the intact worms in vitro.     

Isolation and characterization of hyaluronidase from scorpion (Heterometrus fulvipes) venom

Hyaluronidase (Hyaluronate lyase, E.C. 3.2.1.35) has been isolated from Heterometrus fulvipes scorpion venom by a combination of gel filtration on Sephadex G-75 and ion exchange chromatography on DEAE-cellulose. The enzyme preparation showed a single band on polyacrylamide gel electrophoresis and a molecular weight of 82,000. The final preparation was purified 27-fold. The optimum pH for enzyme activity was 4.0. No loss of activity was observed up to 30 degrees C and showed a sharp decrease in activity at 50 degrees C. Heparin inhibited the enzyme activity.     

Pharmacological and immunological evaluation of scorpion (Heterometrus bengalensis) venom antiserum

An antiserum was prepared for the first time against the venom of a common scorpion, H. bengalensis, by hyperimmunization of rabbit. This antiserum showed positive precipitin bands in immunogeldiffusion and immunoelectrophoresis. The serum showed a high titre value tested by indirect haemagglutination test. The antiserum developed in rabbit protected mice against the lethal action of the venom. Smooth muscle contractile response of venom on guinea pig ileum, and rat uterus was antagonized by the antiserum. This antiserum effectively antagonized the venom induced neuromuscular paralysis tested on rat phrenic nerve diaphragm and chick biventer cervices. Antiserum also protected the venom-induced cardiac arrest tested on isolated guineapig heart and auricle preparations.     

Postnatal development of Schwann cells at neuromuscular junctions,with special reference to synapse elimination

The neuromuscular junctions (NMJs) of postnatal rat soleus muscles were examined by immunohistochemical staining for S100, a marker of Schwann cells (SCs), and for protein gene product 9.5, a neuronal marker, to elucidate the involvement of SCs in synapse elimination. The morphological maturation of S100-immunoreactive terminal SCs at NMJs proceeded with the gradual increase in their number. The number of terminal SCs per NMJ was one or two at postnatal day (P) 7, reaching the adult number at P28, when it became three or four. Confocal laser scanning microscopic analysis of multi-innervated NMJs, whose number decreased between P7 and P14, revealed a change in the ratio between terminal SCs and axons with age. At P7, the ratio between axons and terminal SCs per NMJ was ≥2:1, which was exactly the reverse of that in adults, while at P14 this had changed to 2:2. A structural change appeared to occur at the same time at the preterminal region, this being prior to the establishment of a 1:1 relationship between axon and SC sheath which was detected at P14, with the ≥2:1 relationship seeming to occur at P7. Thus, synapse elimination seems to proceed, at least for one week, with the gradual loss of axons which are at different stages of maturation with respect to their spatial relationship with SCs. From our results it seems unlikely that SCs play an active role in selecting a single axon to survive.     

Synthesis of analogs of peptides from Buthus martensii scorpion venom with potential antibiotic activity

Five analogs of a natural peptide (BmKn1) found in the venom of scorpion Buthus martensii Karsh have been synthesized and tested to compare their antimicrobial and hemolytic activity with the wild type. Circular dichroism spectra show that these peptides form an alpha helix structure and its amino acid positions predict an amphipathic nature. Results show that increasing hydrophobicity by substituting successively positions 5 and 9 of the sequence (on the hydrophobic side of the helix) with alanine, valine and leucine enhances antimicrobial activity and hemolysis. When changes are done on positions 7 and 10 (on the hydrophilic side) by introducing more positive charges with addition of lysine, both activities also increase. However, when negative charges are introduced instead (with glutamic acids), antimicrobial activity is observed but hemolysis is reduced to zero under the concentrations studied. Although strong inhibitory activity begins at low concentrations (10 μg/mL), some peptides level off inhibition and no change is observed as concentrations are increased.     

Hypertension in pregnancy with special reference to its treatment]

Definition and classification of the arterial hypertension in pregnancy are discussed. An emphasis is on the problems of differential diagnosis between pre-eclampsia and other forms of hypertension. Use of hypotensive drugs in pregnant patients with particular reference to emergencies is also discussed. The treatment of pregnant women with hypertension is still a problem which require close co-operation of both an obstetrician and internist. Follow-up after labour is GP duty to find out if the patient remains hypertensive. If so, etiology of the disease should be again searched.