Evolution of flightless land birds on southern continents: transferrin comparison shows monophyletic origin of ratites

In 34 successive patients with Wolff-Parkinson-White syndrome premature beats were induced from the right ventricular apex during reciprocating tachycardia (RT) at progressively shorter coupling intervals. The presence of an accessory pathway was confirmed by a reduction in the atrial cycle length (A-A interval) during which the premature ventricular beat was introduced. This retrograde preexcitation occurred at a time when the His-AV node pathway was refractory; i.e. there was premature activation of the atria over a pathway other than the His-AV node. 3 patients were excluded because of unsatisfactory or unstable H-H intervals. In the remaining 31 patients with constant preceding H-H intervals, the A-A interval shortened; (a) 35-65 msec in 4 patients with right-sided pathways and normal conduction during RT and by 110 msec in a 5th patient with a right-sided pathway, in whom bundle branch block aberration persisted during RT, (b) 45 msec in the single patient with both a right-sided and a septal accessory pathway, (c) 35-65 msec in 5 patients with septal pathways, and (d) 15-35 msec in only 4/20 patients with left-sided pathways and normal conduction during RT. Left-sided ventricular premature beats were introduced in 5 patients with left-sided pathways and normal conduction in RT. In 4/5, left-sided premature beats shortened the A-A interval 40-75 msec whereas right-sided premature beats at the same coupling interval failed to do so. In the fifth case, the left-sided premature resulted in a 65 msec abbreviation of the A-A interval compared to 30 msec from the right ventricular outflow tract and 15 msec from the right ventricular apex. In 5 patients with left-sided pathways, right ventricular premature beats were introduced during RT with left bundle branch block aberration, and shortened the A-A interval 30-50 msec in all of these, whereas right-sided premature beats in 4 of the 5 during normal conduction failed to do so. This technique is useful to confirm the participation of accessory pathways in reciprocating tachycardias associated with the preexcitation syndromes, and emphasizes the importance of the site of stimulation used relative to the location of the accessory pathway. Because of the possibility of multiple accessory pathways, stimulation of the left ventricle should be performed in patients undergoing surgery for preexcitation unless the left ventricle is already inplicated by right-sided studies.     

Motion characteristics of flagellar fragments of long insect sperm

The flagellar length of cricket spermatozoa was reduced in steps from congruent to 1,000 micrometer (intact length) to 50 micrometer. In intact sperm the flagellar wave properties were largely independent of the viscosity of the external medium. When the flagellar length had been reduced to less than 100 micrometer the flagellar frequency was reduced at a raised external viscosity. Independent motion of different sections of a flagellum was not observed when its length is less than 100 micrometer. It is concluded that in long thin flagella, transverse viscous forces cannot exert a moment beyond a lever length of approximately 100 micrometer. It is shown that the existence of a maximum lever length, beyond which no moment can be transmitted, leads to the absence of a standing active contractile moment in the long insect sperm.     

Purification and characterization of a kinin-releasing and fibrinogen-clotting serine proteinase (KN-BJ) from the venom of Bothrops jararaca, and molecular cloning and sequence analysis of its cDNA

Two forms of a proteinase, KN-BJ 1 and 2, were purified to homogeneity from the venom of Bothrops jararaca. In SDS/PAGE reduced KN-BJ 1 and 2 migrated as single bands with molecular masses of 38 kDa and 39 kDa. The two enzymes have similar N-terminal amino acid sequences and specific activities on synthetic chromogenic substrates, and both release bradykinin from bovine low-molecular-mass kininogen. KN-BJ 1 and KN-BJ 2 clot fibrinogen with specific activities of 245 NIH U/mg and 219 NIH U/mg, releasing only fibrinopeptide A. The amidolytic, kinin-releasing and coagulant activities are inhibited by phenylmethylsulfonyl fluoride, demonstrating that KN-BJ is a serine proteinase. Benzamidine derivatives, which are competitive inhibitors of trypsin-like proteinases, also inhibited the amidolytic activity of KN-BJ. A cDNA clone (HS104, 2.2 kb) has been isolated from a cDNA library of B. jararaca venom glands with an ORF of 771 bp. The deduced amino acid sequence contains segments that are identical to the sequences of the N-terminus and three tryptic peptides of KN-BJ 2. Therefore, the cDNA is believed to represent the gene of KN-BJ 2. The deduced amino acid sequence indicates that KN-BJ 2 is synthesized as a prezymogen of 257 amino acids with a putative signal peptide of 18 amino acids and an activating peptide of six amino acid residues. The sequence of 233 amino acids representing the mature enzyme exhibits high similarity to sequences of serine proteinases isolated from crotalid venoms.     

Serological evidence of HTLV-I and HTLV-II coinfections in HIV-1 positive patients in Belém, state of Pará, Brazil

PURPOSE: To report surgical management of solitary hepatic metastasis that occurred 25 years after an enucleation for uveal melanoma. METHODS: A 16-year-old girl, diagnosed with choroidal melanoma and treated with enucleation, was found 25 years later to have liver metastasis affecting the entire left lobe of the liver. RESULTS: She underwent partial hepatectomy with removal of the metastatic melanoma. Four years later, she was found to have a smaller circumscribed nodular melanoma in the remaining right lobe of the liver, also treated with resection. She has remained disease-free for 2 years, with no evidence of systemic disease. CONCLUSION: Surgical excision may be a useful treatment option in selected cases with solitary, circumscribed liver metastasis from uveal melanoma.     

Acute pulmonary embolism: assessment of helical CT for diagnosis

Male pigeons, Columba livia, employ intense mate guarding and frequent copulation apparently as strategies to ensure their paternity. The aim of this study was to investigate the benefits to females of mate guarding by males and frequent copulation. Field observations showed that females initiated the majority of copulations and females that solicited copulations more frequently were guarded more closely by their partner. Experimental removal of guarding male partners showed that: (1) unguarded, fertile females suffered increased harassment from extrapair males which reduced their foraging efficiency; and (2) unguarded, fertile females did not seek copulations with extrapair males. Various explanations for frequent pair copulation initiated by females are discussed and we conclude that female pigeons trade pair copulations for protection (mate guarding) against sexual harassment from other males. Copyright 1998 The Association for the Study of Animal Behaviour.