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Purification and characterization of a soybean hull allergen responsible for the Barcelona asthma outbreaks. II. Purification and sequencing of the Gly m 2 allergen.

BACKGROUND: A low MW allergen from soybean hull, Gly m 1, with two isoallergens, Gly m 1 A and Gly m 1 B, was associated with the asthma outbreaks that occurred in Cartagena, Spain. Using sera of asthmatic epidemic patients (AEP) from Barcelona, three main soybean hull allergens, two of them with MWs and pIs identical to those reported for Gly m 1 A and Gly m 1 B, were identified. OBJECTIVE: The purpose of this study was to purify and to study the N-terminal amino acid sequence of the third allergen, which has a MW of 8 kDa. METHOD: The purification procedure combined the double dialysis method and preparative isoelectofocusing (IEF). Specific IgE determination to the fractions obtained demonstrated three peaks, one of them corresponding to the 8 kDa allergen. The pooled fractions containing this allergen were studied by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE), SDS-PAGE/Western blot and IEF/Western blot. Only a band with a MW of 8 kDa and a pI of 6 was obtained. Its allergenic activity was measured and it was demonstrated that the allergenicity of soybean hull correlates with the presence of the 8 kDa allergen. The N-terminal amino acid sequence of the first 20 amino acids, which was registered at the PIR Data Submission as the N-terminal partial sequence of Gly m 2, was determined according the Edman degradation method. RESULTS: Gly m 2 N-terminal amino acid sequence lacks homology with that reported for the allergen Gly m 1 but has a homology of 71% with a storage protein from cotyledon of Vigna radiata (cow pea) and 64% with a "disease response protein' from Pisum sativum (green pea). These results suggest that Gly m 2 in soybeans could protect against diseases which affect soybean plants. CONCLUSION: This study demonstrates the existence of another soybean hull allergen, Gly m 2, partially responsible for the soybean asthma outbreaks that occurred in Barcelona, Spain.

Allergens↗

Serine proteinase from rice bean.

A trypsin like serine-proteinase of M(r) 16,000 Da, optimally active at pH 8.4 on N-benzoyl-arginine ethyl ester (BAEE) was purified from 4-day old germinated seeds of rice bean, Vigna umbellata (Thunb), by ammonium sulphate precipitation, gel filtration, ion-exchange chromatography and by high performance liquid chromatography (HPLC). The purity of the enzyme was checked by polyacrylamide gel electrophoresis (PAGE). The enzyme activity was studied on natural substrates like casein, haemoglobin and vicilin, a rice bean storage protein. The activity of the enzyme was completely inhibited by phenylmethylsulfonyl fluoride, but not by iodoacetamide and HgCl2, suggesting it to be a serine protease. Loss of activity in presence of EDTA was reversed by addition of Ca2+.

Calcium↗

[Soluble, insoluble and total dietary fiber in raw and cooked legumes].

Soluble (SDF), Insoluble (IDF) and total dietary fiber (TDF) were analysed in 26 samples of the following legumes: Peas (Pisum sativum L) coated and uncoated; beans (Phaseolus vulgaris L), beans (Vigna sinesis L), chick peas (Cicer arietinum L), lentils (Lens culinaris L) and pigeon peas (Cajanus indicus L) raw and cooked, purchased at wholesale level. The AOAC enzimatic-gravimetric method (1990) was used. The cooked grains were drained and dried before analysis. Values for TDF in the raw legumes were 13.6 and 28.9% in chick peas and white beans respectively. In processed grains, values varied from 16.1 and 27.0% in yellow peas uncoated and black beans respectively. As expected the values for IDF were greater in all samples than those for SDF.

Dietary Fiber↗

Occurrence and expression of members of the ferritin gene family in cowpeas.

Ferritin gene expression has been demonstrated in a variety of plants including maize, Arabidopsis, cowpeas, soybeans, beans and peas. Most available evidence shows that the mature protein is located in plastids and its production is under gene transcriptional control. In maize, two different ferritin genes have been identified; they were found to express protein under different physiological conditions. Only single gene products have been found until now in the other plants, with the exception of cowpeas (Vigna unguiculata). Our previous work with cowpeas [Wicks and Entsch (1993) Biochem. Biophys. Res. Commun. 192, 813-819] showed the existence of a family of at least three ferritin genes, each coding for a protein subunit with a unique amino acid sequence. Here we report the discovery of a fourth active gene in cowpeas and present the full cDNA sequences for two of the four known members of the cowpea gene family. We also provide preliminary evidence for a family of ferritin genes in soybeans (Glycine max) related to that in cowpeas. We conclude that a family of genes is probably present in all higher plants. We have used quantitative reverse transcriptase-mediated PCR to show that each of the four members of the cowpea ferritin gene family expresses mRNA in leaves and roots under normal growth with a complete nutrient supply. The results clearly show a marked differential pattern of mRNA levels formed during development from the four genes. We conclude that the composition of plant ferritin molecules from plant leaf extracts is probably a complex mixture of subunits, which might be different in roots and in leaves.

Amino Acid Sequence↗

Optimizing long-term cardiac management after major vascular surgery: Role of beta-blocker therapy, clinical characteristics, and dobutamine stress echocardiography to optimize long-term cardiac management after major vascular surgery.

BACKGROUND: Survivors of major vascular surgery are at increased risk of late cardiac complications. OBJECTIVE: To examine the cardioprotective effect of beta-blockers. METHODS: A follow-up study was conducted in 1286 patients who survived surgery for at least 30 days. Patients were screened for cardiac risk factors and dobutamine stress echocardiography (DSE) results; 1034 patients (80%) underwent preoperative DSE, and 370 (29%) received beta-blockers. The main outcome measure was late cardiac death or myocardial infarction. RESULTS: Seventy-four patients (5.8%) had late cardiac events. Cardiac event rates in patients with 0, 1 to 2, and 3 or more risk factors were 1.6%, 4.7%, and 19.2%, respectively. In patients without risk factors, beta-blockers were associated with improved event-free survival (2.8% vs 0%), and DSE had no additional prognostic value. In patients with 1 to 2 risk factors, the presence of ischemia during DSE increased cardiac events from 3.9% to 9.8%. However, if patients with ischemia were treated with beta-blockers, the risk decreased to 7.2%. In patients with 3 or more risk factors, DSE and beta-blockers stratified patients into intermediate- and high-risk groups. In patients without ischemia, beta-blockers reduced the cardiac event rate from 15.1% to 9.5%, whereas the cardioprotective effect was limited in patients with 3 or more risk factors and positive DSE findings. CONCLUSIONS: Long-term beta-blocker use is associated with a reduction in the cardiac event rate, except for patients with 3 or more risk factors and positive findings on DSE.

Adrenergic beta-Antagonists↗

Localisation of NK1 receptor immunoreactivity to neurons and interstitial cells of the guinea-pig gastrointestinal tract.

Tachykinins, including substance P, neurokinin A, and neuropeptides K and gama, are expressed widely in the peripheral nervous system where they affect smooth muscle contraction, exocrine gland secretion, vascular permeability, and neurotransmission. Substance P, the preferred ligand for the NK1 receptor, is found in high concentrations in the enteric nervous system. In the present study, the localisation and distribution of the NK1 receptor was studied throughout the gastrointestinal tract of the guinea-pig by using a polyclonal antiserum raised against the C-terminal 15 amino acids of the NK1 receptor. Co-localisation with other neuronal markers was examined in the ileum. Nerve cell bodies reactive for the NK1 receptor were found in the myenteric plexus of all regions and the submucous plexus of the small and large intestines. In the small intestine, the interstitial cells of Cajal were also immunoreactive. Immunoreactivity was largely confined to cell surfaces. Almost all immunoreactive myenteric nerve cells had Dogiel type I morphology, and most of these were immunoreactive for nitric oxide synthase, a transmitter of inhibitory neurons to the muscle and of descending interneurons. Neuropeptide Y-containing secretomotor neurons in the submucous and myenteric plexuses also exhibited NK1 receptor immunoreactivity. NK1 receptors were present on a minority of tachykinin immunoreactive neurons of submucous ganglia. The results suggest that receptors on the longitudinal muscle might not be conventional NK1 receptors, that excitation of the circular muscle of the ileum is indirect, perhaps via the interstitial cells of Cajal, and that enteric inhibitory neurons may be excited via NK1 receptors.

Amino Acid Sequence↗

Observations on tumor and metastatic suppressor gene status in endometrial carcinoma with particular emphasis on p53.

BACKGROUND: Genetic changes in the development of endometrial carcinoma have not been characterized, and little is known of tumor or metastatic suppressor gene status in these malignancies. The current study on endometrioid carcinoma was undertaken to examine the status of two tumor suppressor genes that frequently have been found to be altered in human malignancies (the p53 gene and the retinoblastoma [Rb] gene) and to examine the status of the candidate metastatic suppressor gene, nm23-H1. METHODS: The status of the p53 gene was studied by immunohistochemistry of formalin-fixed paraffin-embedded biopsy samples from 72 patients with atypical endometrial hyperplasia or endometrioid carcinoma who underwent hysterectomy immediately after biopsy and from 5 patients with benign endometria. A search for loss of heterozygosity (LOH) of the nm23 gene after DNA extraction from frozen tissues and hybridization with nm23-H1 cDNA specific probe was made in 10 endometrial carcinomas. Rb gene status was evaluated by image analysis quantification of immunoreactive retinoblastoma protein in frozen sections of 10 carcinomas and 2 benign endometria. RESULTS: p53 expression was low in all benign endometria, but high expression was found in 2 (15%) of 13 atypical hyperplasias and in 23 (39%) of 59 carcinomas. High levels of p53 expression in endometrioid carcinoma correlated with the spread of disease outside of the uterus and by logistic regression, the presence of squamous differentiation, nuclear grade, and high p53 expression in the biopsy all independently correlated with spread of disease outside of the uterus. Although 7 of the 10 carcinomas studied were informative, LOH for the nm23 gene was not seen in any, including a site of metastasis. Rb protein expression in endometrial carcinoma was similar to expression in benign endometria. CONCLUSIONS: Although this study found no evidence of nm23-H1 gene alteration or alterations in Rb protein levels in endometrial carcinoma, high expression of p53 protein was sporadically identified in biopsy specimens of atypical hyperplasia and frequently found in endometrioid carcinomas. Determination of p53 expression in combination with the presence or absence of squamous differentiation and nuclear grade in biopsy material may help predict spread of endometrioid carcinoma outside the uterus and facilitate therapeutic planning before hysterectomy.

Adult↗

Generalizability of WAIS-R factor structure within and between populations.

We investigated the reliability of the factor structure of the Wechsler Adult Intelligence Scale-Revised (WAIS-R). The WAIS-R subtests, as administered to 146 head-injured males, were factor analyzed. Two- and three-factor solutions were extracted that were consistent with past findings. Congruence coefficients were computed to determine degree of association between factor structures from all samples reported in the literature. All coefficients were impressive. Also, congruence coefficients based on factor structures derived from different samples within the same population were compared to coefficients based on different samples from different populations. No significant discrepancies emerged. Apparently, the slight factor structure variation that does exist is due to chance data fluctuation rather than to systematic population bias. This reflects well on the robustness of the WAIS-R factor structure.

Adult↗

Methadone maintenance at different dosages for opioid dependence.

BACKGROUND: Methadone maintenance treatment (MMT) is a long term opioid replacement therapy, recognised as effective in the management of opioid dependence. Even if MMT at high dosage is recommended as therapy for reducing illicit opioid use and promoting longer retention in treatment, at present day "the organisation and regulation of the methadone maintenance treatment varies widely". OBJECTIVES: To evaluate the efficacy of different dosages of MMT for opioid dependence in modifying health and social outcomes and in promoting patients' familial, occupational and relational functioning. SEARCH STRATEGY: The following sources were scanned: - MEDLINE (OVID 1966-2001)- EMBASE (1988-2001)- ERIC (1988-2001)- Psychinfo (1947-2001)- Cochrane Controlled Trials Register (CCTR) (1947-2001)- Register of the Cochrane Drug and Alcohol Group (CDAG) (1947-2001)The CDAG search strategy was applied together with a specific MESH strategy. Further studies were searched through: letters to the authors of selected trials or to experts in order to obtain unpublished data. check of references of relevant reviews. SELECTION CRITERIA: Randomised Controlled Trials (RCT) and Controlled Prospective Studies (CPS) evaluating methadone maintenance at different dosages in the management of opioid dependence were included in the review. Non-randomised trials were included when proper adjustment for confounding factors was performed at the analysis stage. DATA COLLECTION AND ANALYSIS: Extraction of data was performed separately by two reviewers. Discrepancies were resolved by a third reviewer. RevMan software was used for analysis. Quality assessments of the methodology of studies were carried out using CDAG checklist. MAIN RESULTS: 22 studies were excluded from the review. 21 studies were included; of them, 11 were RCTs with 2279 people randomised and 10 were CPSs with 3715 people followed-up. OUTCOMES: Retention rate - RCTs: High vs low doses at shorter follow-ups: RR=1.36 [1.13,1.63], and at longer ones: RR=1.62 [0.95,2.77]. Opioid use (self reported), times/w - RCTs: high vs low doses WMD= -2.00 [-4.77,0.77] high vs middle doses WMD= -1.89[-3.43, -0.35] Opioid abstinence, (urine based) at >3-4 w - RCTs: high vs low ones: RR=1.59 [1.16,2.18] high vs middle doses RR=1.51[0.63,3.61] Cocaine abstinence (urine based) at >3-4 w - RCTs: high vs low doses RR=1.81 [1.15,2.85]Overdose mortality - CPSs: high dose vs low dose at 6 years follow up: RR=0.29 [0.02-5.34] high dose vs middle dose at 6 years follow up: RR=0.38 [0.02-9.34] middle dose vs low dose at 6 years follow up: RR=0.57 [0.06-5.06] REVIEWER'S CONCLUSIONS: Methadone dosages ranging from 60 to 100 mg/day are more effective than lower dosages in retaining patients and in reducing use of heroin and cocaine during treatment. To find the optimal dose is a clinical ability, but clinician must consider these conclusions in treatment strategies.

Controlled Clinical Trials as Topic↗

School-based prevention for illicit drugs' use.

BACKGROUND: Drug addiction is a chronic, relapsing disease. Primary interventions should be aimed to reduce first use, or prevent the transition from experimental use to addiction. School is the appropriate setting for preventive interventions. OBJECTIVES: To evaluate the effectiveness of school-based interventions in improving knowledge, developing skills, promoting change, and preventing or reducing drug use versus usual curricular activities or a different school-based intervention . SEARCH STRATEGY: MEDLINE , EMBASE, ERIC, PSYCHINFO, Cochrane Library, ACP Journal Club, Cochrane Drug and Alcohol Group Register, updated to February 2004, were searched. Bibliography of papers was checked and personal contacts were made to identify other relevant studies. SELECTION CRITERIA: RCTs, CCTs or Controlled Prospective Studies (CPS) evaluating school-based interventions designed to prevent substance use. DATA COLLECTION AND ANALYSIS: Data were selected and extracted independently by two reviewers. Quality was assessed with the CDAG checklist. Interventions were classified as skills, affective, knowledge-focused and other characteristics were also studied (teaching, follow-up implementation, context activation). MAIN RESULTS: 32 studies (29 RCTs and 3 CPSs) were included. 28 were conducted in the USA; most were focused on 6th-7th grade students, and based on post-test assessment. RCTs: (1) Knowledge vs usual curricula: Knowledge focused programs improve drug knowledge (SMD=0.91; 95% CI: 0.42, 1.39).(2) Skills vs usual curricula: Skills based interventions increase drug knowledge (WMD=2.60; 95% CI: 1.17-4.03), decision making skills (SMD=0.78; CI95%: 0.46-1.09), self-esteem (SMD=0.22; CI95%: 0.03-0.40), peer pressure resistance (RR=2.05; CI95%: 1.24-3.42), drug use (RR=0.81; CI95%: 0.64, 1.02), marijuana use (RR=0.82; CI95%: 0.73, 0.92) and hard drug use (RR=0.45; CI95%: 0.24-0.85). (3) Skills vs knowledge: No differences are evident.(4) Skills vs affective: Skills-based interventions are only better than affective ones in self-efficacy (WMD=1.90; CI95%: 0.25, 3.55). (5) Affective vs usual curricula: Affective interventions improve drug knowledge (SMD=1.88; CI95%: 1.27, 2.50) and decision making skills (SMD=1.35; CI95%: 0.79, 1.9). (6) Affective vs knowledge: Affective interventions improve drug knowledge (SMD=0.60; CI95%: 0.18,1.03), and decision making skills (SMD=1.22; CI95%: 0.33, 2.12). Results from CPSs: No statistically significant results emerge from CPSs. AUTHORS' CONCLUSIONS: Skills based programs appear to be effective in deterring early-stage drug use. The replication of results with well designed, long term randomised trials, and the evaluation of single components of intervention (peer, parents, booster sessions) are the priorities for research. All new studies should control for cluster effect.

Adolescent↗

Lentiviral vectors: excellent tools for experimental gene transfer and promising candidates for gene therapy.

Lentiviral vectors are tools for gene transfer derived from lentiviruses. From their first application to now they have been strongly developed in design, in biosafety and in their ability of transgene expression into target cells. Primate and non-primate derived lentiviral vectors are now available and with both types of systems a lot of studies tuned to improve their performances in a large number of tissues are ongoing. Here we review the state of the art of lentiviral vector systems discussing their potential for gene therapy.

Animals↗

The impact of interventional cardiology for the management of adults with congenital heart defects.

The objective of this study is to assess the impact of interventional cardiology procedures for the management of ACHD. The interventional approach to the management of CHD in the adult population is becoming increasingly recognized as the preferred treatment option for a wide number of congenital cardiac conditions. The files of all consecutive patients over 18 years of age who were hospitalized in our department from January 2000 to December 2004 were reviewed. Over the study period, 1,115 ACHD (583 women; mean age 41 +/- 13.8, years, range 18-72 years) were hospitalized in our department; 752 patients underwent cardiac catheterization and 82.4% of them had an interventional procedure carried out. ASD (329/620) and PFO (159/620) closure account for 78% of all the procedures carried out, with a 2.7% of major complications incidence (all of them closing ASDs). Other procedures such as stenting aortic coarctation (40/620), ventricular septal defect closure (33/620), patent ductus arteriosus embolization (30/620), pulmonary valvuloplasty (12/620), stenting pulmonary artery branches (8/620), etc (5/620) were carried out. The most important complication was one death, which occurred in the case of a 22-year-old woman after stent implantation for a recurrent aortic coarctation. A trivial residual shunt was detected in only 5% of the patients who had a 6-month follow-up after VSD closure; no residual shunt was found after PDA embolization during the 12-month follow-up. In conclusion, we believe that the interventional approach is a safe and successful treatment option for a wide number of congenital cardiac conditions. The increasing use of catheter interventions for these patients will be responsible for an increase of complex cases in surgery.

Adolescent↗

Morphological characterization of substance P receptor-immunoreactive neurons in the rat spinal cord and trigeminal nucleus caudalis.

Although there is considerable evidence that primary afferent-derived substance P contributes to the transmission of nociceptive messages at the spinal cord level, the population of neurons that expresses the substance P receptor, and thus are likely to respond to substance P, has not been completely characterized. To address this question, we used an antibody directed against the C-terminal portion of the rat substance P receptor to examine the cellular distribution of the receptor in spinal cord neurons. In a previous study, we reported that the substance P receptor decorates almost the entire dendritic and somatic surface of a subpopulation of spinal cord neurons. In the present study we have taken advantage of this labeling pattern to identify morphologically distinct subpopulations of substance P receptor-immunoreactive neurons throughout the rostral-caudal extent of the spinal cord. We observed a dense population of fusiform substance P receptor-immunoreactive neurons in lamina I at all segmental levels. Despite having the highest concentration of substance P terminals, the substantia gelatinosa (lamina II) contained almost no substance P receptor-immunoreactive neurons. Several distinct populations of substance P receptor-immunoreactive neurons were located in laminae III-V; many of these had a large, dorsally directed dendritic arbor that traversed the substantia gelatinosa to reach the marginal layer. Extensive labeling was also found in neurons of the intermediolateral cell column. In the ventral horn, we found that labeling was associated with clusters of motoneurons, notably those in Onuf's nucleus in the sacral spinal cord. Finally, we found no evidence that primary afferent fibers express the substance P receptor. These results indicate that relatively few, but morphologically distinct, subclasses of spinal cord neurons express the substance P receptor. The majority, but not all, of these neurons are located in regions that contain neurons that respond to noxious stimulation.

Afferent Pathways↗

Air pollution and risk of lung cancer in a prospective study in Europe.

To estimate the relationship between air pollution and lung cancer, a nested case-control study was set up within EPIC (European Prospective Investigation on Cancer and Nutrition). Cases had newly diagnosed lung cancer, accrued after a median follow-up of 7 years among the EPIC ex-smokers (since at least 10 years) and never smokers. Three controls per case were matched. Matching criteria were gender, age (+/-5 years), smoking status, country of recruitment and time elapsed between recruitment and diagnosis. We studied residence in proximity of heavy traffic roads as an indicator of exposure to air pollution. In addition, exposure to air pollutants (NO(2), PM10, SO(2)) was assessed using concentration data from monitoring stations in routine air quality monitoring networks. Cotinine was measured in plasma. We found a nonsignificant association between lung cancer and residence nearby heavy traffic roads (odds ratio = 1.46, 95% confidence interval, CI, 0.89-2.40). Exposure data for single pollutants were available for 197 cases and 556 matched controls. For NO(2) we found an odds ratio of 1.14 (95% CI, 0.78-1.67) for each increment of 10 microg/m(3), and an odds ratio of 1.30 (1.02-1.66) for concentrations greater than 30 microg/m(3). The association with NO(2) did not change after adjustment by cotinine and additional potential confounders, including occupational exposures. No clear association was found with other pollutants.

Adult↗

Scatter factor and hepatocyte growth factor are indistinguishable ligands for the MET receptor.

Scatter Factor (SF) is a fibroblast-secreted protein which promotes motility and matrix invasion of epithelial cells. Hepatocyte Growth Factor (HGF) is a powerful mitogen for hepatocytes and other epithelial tissues. SF and HGF, purified according to their respective biological activities, were interchangeable and equally effective in assays for cell growth, motility and invasion. Both bound with identical affinities to the same sites in target cells. The receptor for SF and HGF was identified as the product of the MET oncogene by: (i) ligand binding and coprecipitation in immunocomplexes; (ii) chemical crosslinking to the Met beta subunit; (iii) transfer of binding activity in insect cells by a baculovirus carrying the MET cDNA; (iv) ligand-induced tyrosine phosphorylation of the Met beta subunit. SF and HGF cDNA clones from human fibroblasts, placenta and liver had virtually identical sequences. We conclude that the same molecule (SF/HGF) acts as a growth or motility factor through a single receptor in different target cells.

Animals↗

Extracellular proteolytic cleavage by urokinase is required for activation of hepatocyte growth factor/scatter factor.

The extracellular protease urokinase is known to be crucially involved in morphogenesis, tissue repair and tumor invasion by mediating matrix degradation and cell migration. Hepatocyte growth factor/scatter factor (HGF/SF) is a secretory product of stromal fibroblasts, sharing structural motifs with enzymes of the blood clotting cascade, including a zymogen cleavage site. HGF/SF promotes motility, invasion and growth of epithelial and endothelial cells. Here we show that HGF/SF is secreted as a single-chain biologically inactive precursor (pro-HGF/SF), mostly found in a matrix-associated form. Maturation of the precursor into the active alpha beta heterodimer takes place in the extracellular environment and results from a serum-dependent proteolytic cleavage. In vitro, pro-HGF/SF was cleaved at a single site by nanomolar concentrations of pure urokinase, generating the active mature HGF/SF heterodimer. This cleavage was prevented by specific urokinase inhibitors, such as plasminogen activator inhibitor type-1 and protease nexin-1, and by antibodies directed against the urokinase catalytic domain. Addition of these inhibitors to HGF/SF responsive cells prevented activation of the HGF/SF precursor. These data show that urokinase acts as a pro-HGF/SF convertase, and suggest that some of the growth and invasive cellular responses mediated by this enzyme may involve activation of HGF/SF.

Animals↗

CCK-X receptors in the endothermic mako shark (Isurus oxyrinchus).

By mapping the distribution of cholecystokinin (CCK) receptor types onto an established phylogenetic hypothesis of vertebrate relationships, we tested two hypothesis about the evolution of CCK receptors: (1) A single CCK receptor type, CCK-X, is the ancestral receptor, while CCK-A and CCK-B receptors represent derived receptor types; (2) the evolution of two separate CCK receptors is functionally related to the evolution of endothermy. Specifically, we localized and characterized 125I-CCK-binding sites in the gut and brain of mako shark (Isurus oxyrinchus), a warm-blooded chondrichthyean fish. Competitive inhibition studies of 125I-CCK binding showed that the CCK receptor in the mako shark brain, gallbladder, pyloric stomach, and intestine binds sulfated CCK-8 and sulfated gastrin-17 (gastrin-17-II) with much higher affinity (K(i) ranging from 0.05 to 2.02 nM) than unsulfated gastrin-17 (gastrin-17-I, K(i) ranging from 4.63 to 62.17 nM). These results indicate that the mako shark expresses a single CCK-X receptor in all tissues. Additional competitive inhibition studies showed that the mako CCK-X receptor has very low affinities for the following nonpeptide agonist and antagonists: A71623, L364,718, A57696, A65186.72, Cam-1481, and SR 27897B (specific for some mammalian CCK-A receptors) and L365,260 and CI-988 (specific for some mammalian CCK-B receptors), confirming the pharmacological differences between the CCK-X receptor and the CCK-A and -B receptors. Based on the mapped phylogenetic distribution of CCK receptor types, we conclude that CCK-X is the ancestral receptor type and that two receptor types, e.g. CCK-A and CCK-B, are not part of the suite of characters necessary for evolution of endothermy in fishes.

Animals↗