Isolation and structure of corazonin, a cardioactive peptide from the American cockroach

Corazonin, a new cardioaccelerating peptide, has been isolated from the corpora cardiaca of the American cockroach, Periplaneta americana, and its structure determined to be Glp-Thr-Phe-Gln-Tyr-Ser-Arg-Gly-Trp-Thr-Asn-amide. The peptide stimulated heart beat at concentrations as low as 0.2 nM, which makes it the most potent insect cardioactive neuropeptide.     

Sexual contact in the doctor-patient relationship in The Netherlands.

OBJECTIVE--To obtain data on sexual contact between doctors and their patients. DESIGN--Anonymous questionnaire with 17 items sent to all working gynaecologists (n = 595) and all ear, nose, and throat specialists (n = 380) in the Netherlands. RESULTS--Response rate was 74%; a total 64 doctors gave a reason for not completing the questionnaire. 201 (59%) male gynaecologists and 128 (56%) male ear nose, and throat specialists indicated that sexual feelings are acceptable in the doctor-patient relationship; 286 (85%) and 186 (81%), respectively, had felt sexually attracted to a patient at some time, as had 14 (27%) female gynaecologists. More than half (59%) of the doctors who indicated that sexual feelings are unacceptable in the doctor-patient relationship had experienced these feelings, and 91% of this group had a negative attitude towards these feelings. 4% of respondents in each group had had actual sexual contact with patients. Most gynaecologists were in favour of having more attention paid to sexual problems during training; having their professional society take an official viewpoint; subsequent public support of this viewpoint; and taking on an impartial counsellor for the patients as well as the doctors. CONCLUSION--Sexuality exists in the doctor-patient relationship. Gynaecologists have a higher risk of having sexual contact with their patients than do ear, nose, and throat specialists but compensate for this greater risk by a higher state of recognition and acknowledgement.     

Presence of corazonin in three insect species, and isolation and identification of [His7]corazonin from Schistocerca americana.

An ELISA for corazonin, a cardioactive neuropeptide from the American cockroach, Periplaneta americana, was developed. It was used to isolate corazonin from the cockroach Nauphoeta cinerea, the locust Schistocerca americana, and the hawkmoth Manduca sexta. The peptides from Nauphoeta and Manduca had the same retention times as Periplaneta corazonin, and their amino acid compositions also suggested that these peptides are identical with corazonin. The corazonin-immunoreactive peptide from Schistocerca eluted slightly earlier on HPLC than corazonin, and its structure was determined to be [His⁷]corazonin, or pGlu-Thr-Phe-Gln-Tyr-Ser-His-Gly-Trp-Thr-Asn-amide. These results indicate that corazonin is generally present in insects and that its structure has been well conserved.     

Identification of neuroendocrine cells producing a diuretic hormone in the tobacco hornworm moth,Manduca sexta

Summary Separate antisera were raised to the N- and C-terminal half of the diuretic hormone from Manduca sexta. Antisera against the two halves of this peptide recognized the same cells in M. sexta, and preabsorption of the antisera with the peptides used as antigens abolished the immunoreactivity, confirming their specificity. The antisera reacted with two median neurosecretory cells on each side of the protocerebral groove in larvae, and with a group of about 80 small median neurosecretory cells in the adult, as well as their axons to, and their axon terminals in, the corpora cardiaca. During the early pupal stages, small cells, which are possibly derived from a common neuroblast, differentiate into immunoreactive neurosecretory cells, which explains the large increase in cell numbers in the adult. In the sleepy sulphur butterfly, Eurema nicippe, homologous median neurosecretory cells in the adult were immunoreactive with both antisera.     

Localization of corazonin in the nervous system of the cockroach Periplaneta americana

Antisera raised to the cardioactive peptide corazonin were used to localize immunoreactive cells in the nervous system of the American cockroach. Sera obtained after the seventh booster injection were sufficiently specific to be used for immunocytology. They recognized a subset of 10 lateral neurosecretory cells in the protocerebrum that project to, and arborize and terminate in the ipsilateral corpus cardiacum. They also reacted with bilateral neurons in each of the thoracic and abdominal neuromeres, a single dorsal unpaired median neuron in the suboesophageal ganglion, an interneuron in each optic lobe, and other neurons at the base of the optic lobe, in the tritocerebrum and deutocerebrum. The presence of corazonin in the abdominal neurons and the lateral neurosecretory cells was confirmed by HPLC fractionation of extracts of the abdominal ganglia, brains and retrocerebral complexes, followed by determination of corazonin by ELISA, which revealed in each tissue a single immunoreactive peak co-eluting with corazonin in two different HPLC systems. Antisera obtained after the first three booster injections recognized a large number of neuroendocrine cells and neurons in the brain and the abdominal nerve cord. However, the sera from the two rabbits reacted largely with different cells, indicating that the majority of this immunoreactivity was due to cross-reactivity. These results indicate that the production of highly specific antisera to some neuropeptides may require a considerable number of booster injections.     

Syncytium-inducing (SI) phenotype suppression at seroconversion after intramuscular inoculation of a non-syncytium-inducing/SI phenotypically mixed human immunodeficiency virus population.

Two distinct biological phenotypes of human immunodeficiency virus (HIV) have been described: the non-syncytium-inducing (NSI) phenotype, best characterized by the inability to infect MT-2 cells, and the syncytium-inducing (SI) phenotype, with the ability to infect MT-2 cells. The earliest virus population observed following HIV transmission is generally of the NSI phenotype, even after exposure to inocula of mixed NSI/SI phenotype. In this study, the issue of intrapatient selection of virus phenotype following transmission was addressed by studying two cases of accidental transmission. A comparison of the sequences of the V1-V2 and the V3 coding regions of the envelope gene and the p17 region of the gag gene showed that the donor-recipient pairs were tightly clustered in all gene segments, but away from local and published transmission controls. The intrasample variation of the p17 sequence was greater in the recipients and smaller in the donors than that of the V3 region sequence, indicating selection of V3 at transmission. In these transmission cases, the effects of an intravenous inoculation of a small quantity of blood containing predominantly SI V3 sequences (6 of 8 clonal sequences) were compared with those of an intramuscular inoculation of a large quantity of blood containing predominantly NSI viruses (14 of 16 clonal sequences). Both SI and NSI V3 regions were demonstrated to be phenotypic expressions of genetically related viral strains. The inoculation of the predominantly SI virus population resulted in the persistence of an SI virus population in the recipient and a rapid CD4+ T-cell decline. The inoculation of the predominantly NSI population resulted in a selective amplification of SI viruses before seroconversion, followed by a suppression of SI viruses at seroconversion and a rapid decline of CD4+ T-cell numbers. These data suggest that the suppression of SI viruses can be accomplished following the development of HIV-specific immunity and that the ability to suppress SI viruses does not prevent the development of immunodeficiency.     

Immunocytochemical localization of neurons in the nervous system of the Colorado potato beetle with antisera against FMRFamide and bovine pancreatic polypeptide

Summary Particular neurons in the nervous system of the Colorado potato beetle, Leptinotarsa decemlineata, are recognized by antisera against bovine pancreatic polypeptide and FMRFamide. Both antisera react with the same neurons. Solid phase absorptions showed that antiserum against bovine pancreatic polypeptide cross-reacts with FMRFamide, whereas antiserum against FMRFamide cross-reacts with bovine pancreatic polypeptide. Some of the immunoreactive neurons have axons branching extensively within the neuropile, which suggests that the peptide is used as transmitter. In the corpus cardiacum, a neurohaemal organ in insects, numerous immunoreactive axon terminals are present. Here, the peptide material is presumably released as a hormone.     

Design and rationale of ischaemia-driven complete revascularisation versus usual care in patients with non-ST-elevation myocardial infarction and multivessel coronary disease: the South Limburg Myocardial Infarction (SLIM) trial

Netherlands Heart Journal - To compare ischaemia-driven complete coronary revascularisation by percutaneous coronary intervention (PCI) with usual care in patients with non-ST-elevation myocardial...