The molecular phylogenic tree of the genus Trichinella constructed from isozyme patterns

Six zymograms were compared for extracts of muscle-stage larvae of the seven Trichinella isolates, using isoelectric focusing in polyacrylamide gels. The isozyme patterns of acid phosphatase among them fell into four types. T. pseudospiralis from a raccoon and the Polar strain from a polar bear formed type 1 and type 2, respectively. The Iwasaki strain from a Japanese black bear and the Yamagata strain from a raccoon dog, both from Japan, were type 3. Type 4 consisted of three remaining strains, viz. the Polish strain from a wild pig, the USA strain from a pig, and the Thai strain from a human case, all of which have similar infectivity to pigs. The isozyme patterns of esterase 1, beta-N-acetylglucosaminidase, and peptidase were similar in types 2 and 3. Those of esterase D were common to types 2-4 but not to type 1. In the zymogram of mannosephosphate isomerase, types 2-4 but not type 1 had one common band, whereas in the other bands type 2 was markedly distinguished from types 3 and 4. In the present study, the molecular phylogenic tree was constructed for the first time on the basis of our present and previous electrophoretic data by the use of cluster analysis, and the evolutionary process was considered as follows: T. pseudospiralis (type 1) and T. spiralis (the common ancestor of types 2-4) were initially separated. Next, the common ancestor of the strains from wild carnivores (types 2 and 3) and type 4 were separated. Finally, the Polar strain (type 2) and the Japanese strain (type 3) were separated.

Early development of four Diphyllobothrium species in the final host

The early development of four Diphyllobothrium species, D. latum, D. dendriticum, D. ditremum, and D. vogeli, are described. D. latum sheds the entire larval body easily and shows a high shedding rate of 82.1% on average. On the other hand, D. dendriticum exhibits a different developmental pattern, with a low shedding rate of 8.7% in the hamster and a high shedding rate of 34.9% in the rat. D. ditremum is difficult to recover from hamsters but shows a high shedding rate of 42.9%. D. vogeli shows a constant recovery rate of 38.3% without shedding. The species specificity of these four diphyllobothriids is discussed briefly in relation to the early developmental pattern and the growth rate.

[Efficacy of paromomycin sulfate in the elimination of Diphyllobothrium species and Taenia saginata in clinical cases]

Recently it has been known that paromomycin sulfate had marked anthelmintic activity against some species of tapeworms. In this investigation, paromomycin sulfate was used for treating 6 cases of diphyllobothriasis and 1 case of Taenia saginata infection. Paromomycin sulfate was administered orally in a single dose or 2 divided doses of 40--60 mg/kg, being followed by a purge about 1.5 hours later. Strobila or fragments of proglottids were expelled from 5 cases, of which only 1 scolex was found in a case of infection with marine species of Diphyllobothrium. In 1 case of diphyllobothriasis no worm or worm-fragment was found in the stool even after the second challenge of treatment. Nevertheless follow-up examination for more than 1 month showed no evidence of remaining infection in all cases. Transient dizziness was observed in only 1 case, disappearing within about 30 minutes. Serum- and urine-examinations detected no abnormal signs in all cases excepting 1 case of diphyllobothriasis with suspected hepatitis. It was concluded that paromomycin sulfate is effective therapeutic agent for the treatment of taeniasis and diphyllobothriasis including marine species.

Neuromuscular effects of i.a. infusion of lignocaine in man

Neuromuscular effects of lignocaine during and after i.a. infusion were studied in healthy adult patients, using evoked electromyography. Supramaximal, paired stimuli were applied to the ulnar nerve with variable intervals between the two stimuli. The amplitude of the hypothenar muscle action potential to the second component of the paired stimulus (test response) was compared with that evoked by the first component (conditioning response). During and after i.a. infusion of lignocaine, there were marked decreases of the test response at intervals from 7 to 100 ms after the conditioning stimulus, although the decreases of the conditioning response were slight or negligible. The finding of decreased test responses coincided with the results obtained with tetanic stimulation such as pronounced fade and only slight post-tetanic potentiation. Differences between these findings and those found with muscle relaxants were compared, and it was concluded that the mechanism responsible for these results might be attributed to an effect of lignocaine on the motor nerve terminal.

An electromyographic study of muscle relaxants in man

Supramaximal paired stimuli were applied to the ulnar nerve, and the amplitude of the muscle action potential evoked in the abductor digiti minimi by the second member of the stimulus pair (test response) was compared with that evoked by the first component (conditioning response). The interval between the two components of the stimulus pair (the pair interval) was increased stepwise from 7 to 100 msec and a curve (recovery curve) was obtained by relating the changes in pair interval to the difference in amplitude of the test and conditioning responses. Alterations of the recovery curve (RC) during partial paralysis by muscle relaxants were investigated in healthy adult patients under the lightest plane of general anaesthesia. The control curve obtained in 32 subjects before the administration of a muscle relaxant drug was characterized by slight depressions at very short intervals of paired stimuli, followed by a slight potentiation at 20-100 msec. With non-depolarizing relaxants, RC altered to the characteristic pattern of potentiation at very short intervals of stimuli, followed by a notable depression at longer intervals. In depolarizing blocks with small doses of suxamethonium, the depression of RC at short intervals in the control was enhanced and the pattern of RC was different from that of non-depolarizing agents. When desensitization blocks were instigated by the i.v. administration of suxamethonium, the RC patterns were similar to those of competitive agents.