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Biomedical subjects

R Herranz

Publications and source records attributed to R Herranz.

At least 19 recordsLinked to original sources
PubMed2004

Pharmacological study of IQM-97,423, a potent and selective CCK1 receptor antagonist with protective effect in experimental acute pancreatitis.

The pharmacological profile of the new CCK1 receptor antagonist IQM-97,423, (4aS,5R)-2-benzyl-5-(tert-butylaminocarbonyl-tryptophyl)amino-1,3-dioxoperhydropyrido-[1,2-c]pyrimidine, was examined in in vitro and in vivo studies and compared with typical CCK1 antagonists such as devazepide and lorglumide. IQM-97,423 showed a high affinity at [3H]-pCCK8-labeled rat pancreatic CCK1 receptors, and was virtually devoid of affinity at brain CCK2 receptors. IQM-97,423 antagonized CCK8S-stimulated alpha-amylase release from rat pancreatic acini with a potency similar to devazepide and much higher than lorglumide. In the guinea pig isolated longitudinal muscle-myenteric plexus preparation, IQM-97,423 produced a full antagonism of the contractile response elicited by CCK8S and a weaker effect on the contraction elicited by CCK4, suggesting a selective antagonism at CCK1 receptors. The protective effect of IQM-97,423 and devazepide was tested in two models of acute pancreatitis in rats, induced by injection of cerulein or by combined bile and pancreatic duct obstruction. The new compound fully prevented the cerulein-induced increase in plasma pancreatic enzymes and in pancreas weight with a potency similar to devazepide. In common bile-pancreatic duct ligature-induced acute pancreatitis, IQM-97,423 partially prevented, like devazepide, the increase in plasma pancreatic enzyme activity and in pancreas weight. Consequently, the pyridopyrimidine derivative IQM-97,423 is a potent and highly selective CCK1 receptor antagonist with preventive effects in two experimental models of acute pancreatitis and a potential therapeutic interest.

Acute Disease↗
PubMed2002

The long-term adaptation of multicellular model organisms to non-terrestrial and space environments.

The main point in this presentation is the following: It is of crucial importance that the Space Agencies define and support the long-term directions for Space Biology Research. The development and upgrading of Facilities and Carriers should be coordinated with the preparatory activities of scientific groups interested in tackling major questions using the future opportunities in the Space Exploration Programs. The current effort in establishing larger Research Networks may lead the way to a successful Space Program in the XXI Century.

Journal Article↗
PubMed2002

Towards the establishment of a permanent colony of Drosophila in the International Space Station: hardware tests and adaptation of techniques.

Our group has the long-term goal of establishing a permanent colony of Drosophila melanogaster in the International Space Station (ISS) to study its long-term adaptation to this unusual environment. We are currently building an enhanced version of an automatic cultivation unit (ESE1) in which we can grow flies with minimal crew involvement. We are working on a fixation unit as well. We are also adapting current protocols to maintain fixed animals during at least three months, the minimal refurbishment shuttle flight time, with minimal handling and maximal automatization, that can be used for inmuno-cytochemistry, ultrastructure or molecular experiments.

Journal Article↗
PubMed2001

Pathologic downstaging of T3-4Nx rectal cancer after chemoradiation: 5-fluorouracil vs. Tegafur.

PURPOSE: To describe downstaging effects in locally advanced rectal cancer induced by 2 fluopirimidine radiosensitizing agents given through different routes in conjunction with preoperative radiotherapy. METHODS AND MATERIALS: From March 1995 to December 1999, two consecutive groups of patients with cT3-4Nx rectal cancer (94% CT scan, 71% endorectal ultrasound) were treated with either (1) 45-50 Gy (1.8 Gy/day, 25 fractions) and 5-fluorouracil (5-FU) (500-1,000 mg/m2 by 24-h continuous i.v. infusion on Days 1-4 and 21-25) or (2) oral Tegafur (1,200 mg/day on Days 1-35, including weekends). Surgery was performed 4 to 6 weeks after the completion of chemoradiation. RESULTS: The total T downstaging rate was 46% in the 5-FU group and 53% in the Tegafur group. Subcategories were downstaged by the sensitizing agents (5-FU vs. Tegafur) as follows: pT0-1, 14% vs. 23%; pT2, 32% vs. 32%; pT3, 49% vs. 37%; pT4, 5% vs. 7%; and N(0), 74% vs. 86%. Analysis of residual malignant disease in the specimen discriminated mic/mac subgroups (mic: <20% of microscopic cancer residue), with evident superior downstaging effects in the Tegafur-treated group: pTmic 23% vs. 58% (p = 0.002). CONCLUSIONS: When administered concurrent with pelvic irradiation, oral Tegafur induced downstaging rates in both T and N categories superior to those induced by intermediate doses of 5-FU by continuous i.v. infusion. In this pilot experience, oral Tegafur reproduced the characteristics of downstaging described previously when full doses of 5-FU have been combined with radiotherapy.

Adult↗
PubMed2001

5-(Tryptophyl)amino-1,3-dioxoperhydropyrido[1,2-c]pyrimidine-based potent and selective CCK(1) receptor antagonists: structure-activity relationship studies on the central 1,3-dioxoperhydropyrido[1,2-c]pyrimidine scaffold.

To further define the pharmacophore of the potent and selective 5-(tryptophyl)amino-1,3-dioxoperhydropyrido[1,2-c]pyrimidine-based CCK(1) receptor antagonists the electronic and topographic properties of the central 1,3-dioxoperhydro-pyrido[1,2-c]pyrimidine scaffold have been modified. With this aim, the 1- and 3-oxo groups have been replaced by the thioxo- and deoxi-analogues, and the fused piperidine ring has been contracted to the corresponding pyrrolidine moiety. The results of the evaluation of the new analogues as CCK receptor ligands, in rat pancreas and cerebral cortex preparations, showed that, whereas replacement of oxygen with sulfur is allowed, reduction of the 1- or 3-oxo groups or the contraction of the fused piperidine ring lead to the complete loss of binding affinity at CCK(1) receptors. The thioxo-analogues 5a, 8a, 12a, and 12b showed functional CCK(1) antagonist activity, inhibiting the CCK-8-stimulated amylase release from pancreatic acinar cells. The 1-thioxo analogue 5a, with subnanomolar affinity (IC(50) = 0.09 x 10(-9) M), was found to be the most potent and selective compound within the family of 5-(tryptophyl)amino-1,3-dioxoperhydropyrido[1,2-c]pyrimidine-based CCK(1) antagonists.

Animals↗
PubMed2001

5-(Tryptophyl)amino-1,3-dioxoperhydropyrido[1,2-c]pyrimidine-based potent and selective CCK(1)receptor antagonists: structure-activity relationship studies on the substituent at N2-position.

To establish structure-activity relationships a new series of analogues of the highly potent and selective CCK(1) receptor antagonist (4aS,5R)-2-benzyl-5-(N-Boc-tryptophyl)amino-1,3-dioxoperhydropyrido[1,2-c]-pyrimidine (1a) modified at N2-position of the central scaffold has been prepared and evaluated as CCK receptor ligands. With this aim the N2-benzyl group has been replaced by methyl, cyclohexyl, aromatic groups, 1-phenylethyl, and 1-carboxy-2-phenylethyl group. Then, substituents with different electronic and steric properties were introduced into different positions of the phenyl group of analogues 19a and 19b. The results of the CCK receptor binding and in vitro functional activity evaluation suggest the importance of the lipophilic character and an appropriate spatial orientation of the moiety linked at the N2-position of the 1,3-dioxoperhydropyrido[1,2-c]pyrimidine template for potent and selective binding and antagonist activity at CCK(1) receptor subtype. The 2-cyclohexyl and (2S)-1-naphthyl derivatives 18a and (2S)-20a have emerged as more potent and selective CCK(1) receptor antagonists than the lead compound 1a. Additionally, the results confirm the (4aS,5R)-stereochemistry at the central bicyclic skeleton as an essential structural requirement for potent binding to this receptor subtype.

Amylases↗
PubMed2001

Entry to new conformationally constrained amino acids. First synthesis of 3-unsubstituted 4-alkyl-4-carboxy-2-azetidinone derivatives via an intramolecular N(alpha)-C(alpha)-cyclization strategy.

A systematic study on the base-assisted intramolecular alkylation of N-benzyl-N-chloroacetyl amino acid derivatives is described. This study resulted in the first concise and versatile route to the preparation of 3-unsubstituted 4-alkyl-4-carboxy-2-azetidinones, to be included into the scarce family of beta-lactams with quaternary centers at the C(4) position. Particularly noteworthy is that the intramolecular N(alpha)-C(alpha)-cyclization of Phe and Leu derivatives afforded the corresponding beta-lactam derivatives with moderate enantioselectivity (up to 56%). It is suggested that, in these particular cases, the cyclization reaction proceeds by way of planar enolate intermediates, which possess dynamic chirality. The described sequence of reactions, that is compatible with commonly used protecting moieties for the alpha-carboxy group, cannot be applied to dipeptides, since the cyclization to the six-membered 2,5-diketopiperazine ring occurs preferentially.

Amino Acids↗
PubMed2001

Conformationally restricted PACAP27 analogues incorporating type II/II' IBTM beta-turn mimetics. Synthesis, NMR structure determination, and binding affinity.

To probe the importance of a proposed beta-turn within residues S9-R12 of PACAP for recognition by VIP/PACAP receptors, compounds 1 and 2, two conformationally restricted analogues of PACAP27 incorporating respectively (S)- or (R)-IBTM as type II or II' beta-turn dipeptide mimetic at the Y10-S11 position, were synthesized. According to 1H NMR conformational analyses in aqueous solution and 30% TFE, both PACAP27 and the [S-IBTM(10,11)]PACAP27 analogue 1 adopt similar ordered structures. PACAP27 shows an N-terminal disordered region (residues H1-F6) and an alpha-helical conformation within segment T7-L27. For residues S9-R12, our data seem more compatible with a segment of the alpha-helix than with the beta-turn previously proposed for this fragment. In compound 1 the alpha-helix, also spanning T7-L27 residues, appears slightly distorted at the N-terminus relative to the native peptide. Although this distortion could lead to the marked decrease in binding affinity of this compound at the VIP/PACAP receptors, the lack of the Y10 side chain in analogues 1 and 2 could also significantly affect the binding of these compounds.

Amino Acid Sequence↗
PubMed2001

99mTc-MIBI scintimammography as a complement of the mammography in patients with suspected breast cancer. A multicentre experience.

The aim of this work has been to evaluate the clinical usefulness of 99mTc-MIBI scintimammography, used as a complement to mammography, in the study of patients with suspected breast cancer. We performed prone breast scintigraphy in 253 patients (268 lesions) with suspected breast cancer. The size and degree of the suspected breast cancer was evaluated by mammography. Diagnosis was established by biopsy. Malignancy was diagnosed in 155 lesions and benign diseases in 113. The results of the scintimammography were a sensitivity of 91%, a specificity of 71%, PPV=81% and NPV=85%. In lesions smaller than 1 cm, sensitivity and specificity were 57% and 100%; in lesions with a diameter of between 1 and 2 cm, these figures were 90% and 72% respectively, and in lesions of more than 2 cm the sensitivity was 99% and the specificity 50%. On mammography, 155 lesions were considered as having a high suspicion of malignancy, whilst 72 were indeterminate and 41 had a low probability. In lesions with a low or indeterminate suspicion of malignancy on mammography, the sensitivity and NPV of the scintimammography were 97% and 98%. Scintimammography is a useful technique in the study of lesions where breast cancer is suspected. Scintimammography results are closely related to tumour size and the degree of mammographic suspicion. Scintimammography can be useful where mammography identifies lesions with a low or indeterminate suspicion of malignancy.

Journal Article↗
PubMed2001

Gamma-detecting probe used intraoperatively to locate the sentinel lymph node in patients with malignant melanoma.

OBJECTIVE: To assess the usefulness of lymphoscintigraphy and intraoperative gamma probe in the detection of sentinel lymph nodes. DESIGN: Prospective open study. SETTING: University hospital, Spain. SUBJECTS: 40 patients with malignant melanoma (24 stage I/II, 16 stage III). INTERVENTION: The day before operation a lymphoscintigram with 99mTc-nanocolloid was taken and the first lymph node identified was considered to be the sentinel node. A hand-held gamma probe was used for intraoperative mapping. MAIN OUTCOME MEASURE: Identification of the sentinel node. RESULTS: Sentinel nodes were identified in 39/40 patients (98%). In 24 patients with stage I/II disease, 34 sentinel nodes were found (6 invaded and 28 clear of melanoma). A total number of 161 regional lymph nodes were harvested, none of them invaded by melanoma. In 16 patients with stage III disease, 22 sentinel nodes were located (14 invaded and 8 clear of melanoma). A total of 89 regional lymph nodes were excised in patients with invaded sentinel nodes (44 of which were invaded and 45 clear of disease). 41 lymph nodes were excised from patients with clear sentinel nodes, and all were also clear of melanoma. CONCLUSIONS: We conclude that this is a useful technique for the selection of patients with melanoma who may require lymphadenectomy.

Adult↗
PubMed2000

beta-Turned dipeptoids as potent and selective CCK(1) receptor antagonists.

To improve our knowledge of the bioactive conformation of CCK(1) antagonists, we previously described that replacement of the alpha-MeTrp residue of dipeptoids with the (2S,5S, 11bR)-2-amino-3-oxohexahydroindolizino[8,7-b]indole-5-carbox ylate (IBTM) skeleton, a probed type II' beta-turn mimetic, led to restricted analogues (2S,5S,11bR,1'S)- and (2S,5S,11bR, 1'R)-2-(benzyloxycarbonyl)amino-5-[1'-benzyl-2'-(carboxy)ethyl]carbam oyl-3-oxo-2,3,5,6,11,11b-hexahydro-1H-indolizino[8,7-b]indole, 1a,b, showing high binding affinity and selectivity for CCK(1) receptors. In this report, we describe the synthesis and binding profile of new analogues of compounds 1 designed to explore the importance of the C-terminal residue and of the type of beta-turn on the receptor binding affinity and selectivity. Structure-affinity relationship studies show that a C-terminal free carboxylic acid and an S configuration of the Phe and betaHph residues are favorable for CCK(1) receptor recognition. Moreover, selectivity for this receptor subtype is critically affected by the beta-turn type. Thus, while compounds 15a and 16a, containing the (2S,5S,11bR)- and (2R,5R, 11bS)-IBTM frameworks, respectively, are both endowed with nanomolar affinity for CCK(1) receptors, restricted dipeptoid derivative 15a, incorporating the type II' IBTM mimetic, shows approximately 6-fold higher CCK(1) selectivity than analogue 16a, with the type II mimetic. From these results, we propose that the presence of a beta-turn-like conformation within the peptide backbone of dipeptoids could contribute to their bioactive conformation at the CCK(1) receptor subtype. Concerning functional activity, compounds 15a and 16a behave as CCK(1) receptor antagonists.

Animals↗
PubMed2000

Indium-111 labelled platelet scintigraphy can predict the immunological origin of fever in patients on dialysis carrying a non-functioning renal allograft.

The purpose of this study was to evaluate the usefulness of labelled platelet scintigraphy in the differential diagnosis of a prolonged febrile syndrome (PFS) in patients on dialysis carrying a non-functioning renal allograft. We prospectively performed an indium-111 mercaptopyridine-labelled platelet scan on 91 patients (54 men, 37 women; mean age 39.6+/-12 years). The mean duration of PFS was 35 days (range 7-122). Forty-six of the 91 patients underwent steroid therapy (2-10 mg/day). Platelet labelling was carried out following Thakur's method. Platelet scans were performed 48 h after reinjection of labelled platelets. The platelet uptake index (PUI) was calculated by dividing the cpm/pixel in the allograft ROI by cpm/pixel in a mirror background ROI. The final diagnosis of PFS was established depending on the outcome after treatment. In 61/91 patients the fever had an immunological origin because it disappeared after graft embolisation or transplantectomy. In 30/91 patients the PFS disappeared after antibiotic therapy (non-immunological origin). The PUI in patients with immunological PFS was 1.80+/-0.7, while in patients with non-immunological PFS it was 1.12+/-0.1 (P<0.05). When a PUI of > or =1.5 was considered as the threshold to establish PFS of immunological origin, the sensitivity of platelet scan was 76%, the specificity 100%, and the negative and positive predictive values 69% and 100%, respectively. In patients classified with immunological PFS who underwent steroid therapy, the PUI was significantly lower than in patients without steroids (P<0.05). These results suggest that 111In-labelled platelet scintigraphy can accurately predict an immunological PFS in patients on dialysis carrying a non-functioning renal allograft. Therapy with steroids could reduce the sensitivity of 111In-labelled platelet scintigraphy in detecting immunological PFS.

Abdomen↗
PubMed2000

[Treatment of metastatic bone pain with repeated doses of strontium-89 in patients with prostate neoplasm].

This study has aimed to evaluate the usefulness of repeated treatment with 89Sr in patients with prostate neoplasm and metastatic bone pain. Seventeen patients with partial or complete response after the first dose were retreated with two or more doses (total of 39 doses). The Karnofsky functional status, pain and degree of analgesia were assessed. After the first dose the response was good in 68% of the patients and partial in 32%. After the second dose, the response was good in 62% of the patients, partial in 15% and there was no response in 23% of the cases. The pre-treatment Karnofsky functional status and duration of the effect of 89Sr was lower after the second dose (p = 0.03, p = 0.02), but there were no statistically significant differences in the type of response. In conclusion, re-treatment with 89Sr can be administered safely and with a similar response to that achieved after the first dose.

Aged↗
PubMed2000

Optimization of technetium-99m-HMPAO leukocyte scintigraphy in evaluation of active inflammatory bowel disease.

Although [99mTc]HMPAO-labeled leukocyte scintigraphy is widely used in the assessment of IBD, the time point chosen for imaging is still controversial. The aim of the present study was to determine the optimal scanning sequence to assess IBD extension and activity. Sixty-two consecutive patients with active and 18 with inactive IBD were prospectively studied. Clinical evaluation, colonoscopy, radiology, and scintigraphy were performed within three days, without changes in the patient's treatment. Compared to early scan (45 min), late scan (3 hr) had a higher sensitivity (85% vs 100%) and accuracy (85% vs 95%) in identifying patients with active IBD and in defining IBD extension. Combinations of values from both scans did not improve accuracy of scintigraphy, which is lower in Crohn's disease than in ulcerative colitis and also in patients receiving steroid treatment. In conclusion, a single late scintigraphy scan provides the best means to identify patients with active IBD and to assess disease extension.

Adolescent↗
PubMed1999

5-(Tryptophyl)amino-1,3-dioxoperhydropyrido[1,2-c]pyrimidine-based potent and selective CCK(1) receptor antagonists: structural modifications at the tryptophan domain.

Analogues of the previously reported potent and highly selective CCK(1) receptor antagonist (4aS, 5R)-2-benzyl-5-(N-Boc-tryptophyl)amino-1,3-dioxoperhydropyrido-[1, 2-c]pyrimidine (2a) were prepared to explore the structural requirements at the Boc-tryptophan domain for CCK(1) receptor affinity. Structural modifications of 2a involved the Trp side chain, its conformational freedom, the Boc group, and the carboxamide bond. Results of the CCK binding and in vitro functional activity evaluation showed three highly strict structural requirements: the type and orientation of the Trp side chain, the H-bonding acceptor carbonyl group of the carboxamide bond, and the presence of the Trp amino protection Boc. Replacement of this acid-labile group with 3, 3-dimethylbutyryl or tert-butylaminocarbonyl conferred acid stability to analogues 14a and 15a, which retained a high potency and selectivity in binding to CCK(1) receptors, as well as an in vivo antagonist activity against the acute pancreatitis induced by caerulein in rats. Oral administration of compounds 14a and 15a also produced a lasting antagonism to the hypomotility induced by CCK-8 in mice, suggesting a good bioavailability and metabolic stability.

Acute Disease↗
PubMed1999

[Sentinel lymph node detection with lymphoscintigraphy and intraoperative probe in malignant melanoma patients].

BACKGROUND: The sentinel lymph node is the first node in a lymphatic basin to receive lymphatic drainage from a tumor site. If this node is free of tumor, then radical lymphadenectomy may be avoided. The goal of this study was to assess the usefulness of lymphoscintigraphy and intraoperative gamma probe in the sentinel node detection in patients with malignant melanoma. METHOD: We prospectively studied 40 patients with malignant melanoma (24 in I/II stages and 16 in III stage). The day before surgery a lymphoscintigraphy with 99mTc-nanocolloid was performed and the first lymph node identified was considered as sentinel node. For intra-operative mapping a hand-held gamma probe was used. RESULTS: Sentinel nodes were identified in 39/40 (97.5%) patients. In 24 patients with I/II stages 34 sentinel nodes were demonstrated (six positive and 28 negative for malignant melanoma). A total amount of 161 regional lymph nodes was harvested, all of them being negative for malignant melanoma. In 16 patients with III stage, 22 sentinel nodes were located (14 positive and eight negative for malignant melanoma). A total of 89 regional lymph nodes were excised in sentinel nodes positive patients (44 positive and 45 negative for malignant melanoma) and 36 lymph nodes in sentinel node negative, all of them negative for malignant melanoma. CONCLUSIONS: In patients with malignant melanoma, lymphoscintigraphy with 99Tc-nanocolloid is useful for the detection of sentinel lymph node. Biopsy of this node is useful for the selection of patients to undertake a lymphadenectomy.

Adult↗
PubMed1999

Highly constrained dipeptoid analogues containing a type II' beta-turn mimic as novel and selective CCK-A receptor ligands.

Conformationally constrained dipeptoid analogues containing the type II' beta-turn mimic (2S,5s,11bR)-2-amino-3-oxohexahydroindolizino[8,7-b]indole-5 -carboxylate framework in place of the alpha-MeTrp residue, show high binding affinity and selectivity for CCK-A receptors, suggesting that a turn-like conformation could contribute to the bioactive conformation at this CCK receptor subtype.

Animals↗