Emesis and space motion sickness in amphibians.

Amphibians possess the ability to vomit in response to a variety of stimuli that provoke emesis in mammals. Pharmacological studies have establish that the ejection of gastric contents and the basic mechanism for vomiting have been phylogenetically conserved among these tetrapods. As part of on-going comparative studies on emesis in vertebrates, we previously documented that some postmetamorphic anurans and salamander larvae experience motion-induced emesis when exposed to the provocative stimulus of parabolic aircraft flight. However, more recent experiments suggest that there are strict conditions for inducing emesis in amphibians exposed to parabolic flight and that amphibians are not as sensitive to this stimulus as mammals. Further studies on emesis in lower vertebrates may help us understand the processes that cause emesis in abnormal gravitational regimes.

Isolation and characterization of a novel bioactive peptide, Carassius RFamide (C-RFa), from the brain of the Japanese crucian carp.

A novel bioactive peptide with the C-terminal RFamide was isolated from the brain of the Japanese crucian carp, Carassius auratus langsdorfii, by using the intestine of the fish as the bioassay system. The primary structure of the peptide was determined to be SPEIDPFWYVGRGVRPIGRFamide and it was designated Carassius RFamide (C-RFa). The sequence of C-RFa was found to be significantly homologous to the molluscan neuropeptide termed Achatina cardioexcitatory peptide 1 (ACEP-1). Both peptides have RPXGRFamide structure in their C-terminal moieties. C-RFa was found to have an excitatory effect on visceral muscle tissues of fish, newt, quail, and rat. In the stomach of the fish, Zacco temminckii, IGRFamide (C-RFa 17-20) was shown to be the minimal structure required for the excitatory effect and PIGRFamide (C-RFa 16-20) to be almost equipotent with the parent peptide C-RFa.

[Clinical significance of extended mediastinal lymph node dissection on the basis of clinicopathological analysis of nodal involvement in bronchogenic carcinoma].

During the past 20 years, 1,064 cases of non-small cell lung cancer underwent resectional surgery in which all accessible mediastinal lymph nodes were dissected. Among 288 patients with histologically proven N2 disease, 182 underwent complete dissection of the mediastinal lymph nodes; 77 had one-level and 105 had multi-level metastases. Fifteen percent of the patients having primary lesions with a maximal diameter between 21 and 30 mm had N2 disease. Nodal metastases to the lower mediastinum from upper lobe cancer (nonregional metastasis) were frequently observed as were metastases of lower lobe cancer to the upper mediastinum. In addition, there were often skip metastases to the nonregional parts of the mediastinum without regional nodal involvement in the mediastinum. Among left-lung cancer patients, the group that underwent nodal dissection after mobilization of the aorta by dividing the Botallo's ligament frequently had a verified metastatic node at the tracheo-bronchial angle (#4) which might not have been detected without that procedure. In addition, many N2 and N3 diseases were detected by additional dissection through a median sternotomy. From the results of the present study, it appears that extensive mediastinal dissection should be recommended in surgery for lung cancer irrespective of the location and the size of the primary tumor.

[A study of a regional lymph node metastasis in a well-differentiated thyroid carcinoma].

Forty-eight patients with a well-differentiated thyroid cancer that occupied unilateral lobe were given, a modified radical neck dissection (unilateral or bilateral). After an examination of their lymph nodes, a retrospective analysis showed that the metastasis extended to the lateral cervical lymph node on the ipsilateral neck in 43.8% of all cases, and to at least the paratracheal lymph node on the contralateral neck in 27.2% of all cases. Therefore a bilateral modified radical neck dissection is needed surgical treatment for such patients.

Biological activities of ganglion extracts from a prosobranch mollusc, Fusinus ferrugineus.

Acetone extract of the ganglia of Fusinus ferrugineus was applied to C-18 cartridges, and the flowthrough and retained materials were bioassayed on the radula retractor muscle of the animal. The flowthrough was found to have a potent contractile action and the retained material a potent contraction-inhibiting action in addition to a weak contractile action. The retained material was then applied to a column (2.6 x 40 cm) of Sephadex G-15. Fractions of 4 ml each were collected, and their activities were assayed on twitch contractions of the radula retractor. Three peaks (E1, E2 and E3) of contraction-potentiating activity and one peak (I) of contraction-inhibiting activity were obtained. The maximum activities of peaks E1, E2 and E3 were found at fractions 22, 44 and 50, respectively. The maximum activity of peak I was found at fractions 28-30. All of the activities of these peaks were destroyed by incubating the fractions with the peptidase subtilisin, suggesting that the active substances in the peaks are peptides. Using some kinds of molluscan muscles, the actions of the substances were examined in greater detail. The results suggest that peak E1 may contain a novel excitatory peptide whose molecular weight is more than 1,000, and that peaks E2 and E3 may contain FMRFamide-related peptides. It is also suggested that peak I may contain two or more myomodulin-CARP-related inhibitory peptides.

Structures and actions of Mytilus inhibitory peptides.

Two congeneric peptides that inhibit contraction of the anterior byssus retractor muscle of Mytilus edulis were isolated from the pedal ganglia of the mussel. Their structures were determined to be H-Gly-Ser-Pro-Met-Phe-Val-NH2 and H-Gly-Ala-Pro-Met-Phe-Val-NH2. These hexapeptides also showed inhibitory action on contractions in several other molluscan muscles, such as the cardiac muscle of Meretrix lusoria and the penis retractor muscle of Achatina fulica.

Spectral sensitivity of melanophores of a freshwater teleost, Zacco temmincki.

1. The melanophores of a freshwater teleost, Zacco temmincki, responded to changes in illumination: in darkness the melanophores induced a melanosome aggregation and when subjected to light they caused a melanosome dispersion. 2. Using monochromatic light, the spectral sensitivity of the melanophores was examined. 3. The melanophores showed a different sensitivity to light between 400 and 600 nm with a maximum at about 525 nm. 4. The action spectrum closely resembled a porphyropsin absorbance curve, suggesting a porphyropsin or similar photopigment is active in the melanophore light response of Zacco temmincki.

Catch-relaxing peptide isolated from Mytilus pedal ganglia.

A peptide that relaxes catch tension of the anterior byssus retractor muscle of Mytilus edulis was purified from pedal ganglion extracts of the mussel. Its primary structure was determined to be H-Ala-Met-Pro-Met-Leu-Arg-Leu-NH2. This peptide was found to have not only catch-relaxing action on the byssus retractor muscle but also modulatory actions on contractions in various molluscan muscles.

Local light stimulation of melanophores of a teleost, Zacco temmincki.

Responses of melanophores of the teleost, Zacco temmincki, to local light stimulation were examined in preparations of isolated scales. The melanophores induced the aggregation of melanosomes in darkness and their dispersion in light. Local illumination of a melanophore in the melanosome-dispersed state inhibited centripetal migration of melanosomes only in the stimulated area. Local illumination of a pigment-free branch of a melanophore with aggregated melanosomes generally brought about pigment dispersion into the stimulated area. However, when that area was at a significant distance from the edge of the central melanosome mass, the melanosomes never migrated into the irradiated area. Local illumination of the centrosphere of a cell inhibited the full aggregation of melanosomes in the dispersed and aggregated state. The degree of the inhibition depended on the size of the irradiated area. The results suggest that photoreceptive sites are distributed over the whole of a cell, and that the movements of melanosomes are regulated locally in a very precise manner.

Melanophores of Zacco temmincki (Teleostei) are light sensitive.

The responses of melanophores of a cyprinid fish Zacco temmincki to changes in illumination were examined in isolated scale preparations of the adult fishes. Melanosomes in the melanophores aggregated in darkness and dispersed in light. These responses were invariably induced, even in denervated melanophores. These light responses, the dark-induced aggregation and the light-induced dispersion, were not affected by a number of alpha and beta adrenergic blocking agents. It was concluded that the melanophores of Zacco temmincki were themselves light sensitive and responded directly to light by melanosome translocations. The light responses were quantitatively assessed in relation to the intensity of illumination.

Action of melanophore-stimulating hormone on melanophores of the cyprinid fish Zacco temmincki.

1. Alpha MSH was extremely effective in inducing melanosome dispersion in both innervated and denervated melanophores in isolated scales of Zacco termmincki. 2. The sensitivity of the melanophores to MSH did not change after denervation. 3. The MSH action was blocked by mersalyl, a SH inhibitor, but not by any of alpha and beta adrenergic blockers. 4. Ca2+ was required for the MSH action, but not for melanosome dispersion itself, since the beta adrenergic response was normally produced in the absence of this ion. 5. Mg2+, Sr2+ and Ba2+ could not replace the Ca2+. 6. Mn2+ reversibly inhibited the MSH action.

Variation in courtship sounds among three geographical strains of Drosophila mercatorum.

Sound recordings of courtship in Drosophila mercatorum were analyzed with an oscilloscope. Sounds in this species consist of two kinds of pulses, referred to as the A and B sounds, respectively. These differ from each other in their oscilloscope pattern and in the behavior accompanying them. A comparative study of three strains from widely separated geographical regions (New York, El Salvador, and Hawaii) revealed significant differences among strains in the interpulse interval (ipi) of the A sound. The ipi of the B sound increased as it proceeded for New York and Hawaii males but not for males from El Salvador. These characteristics may influence mating success in interstrain crosses. The present results suggest that the first steps toward divergence in the nature of the sound are quantitative; this may affect the response threshold of the female. Genetic systems responsible for female receptivity may have been independently developed in the two sexes.