Characterization of chicken lung angiotensin I-converting enzyme.

Angiotensin I(AI)-converting enzyme (ACE) (EC 3.4.15.1) was solubilized from the membrane fraction of chicken lung using trypsin and nonidet P40 extraction, and then purified to homogeneity by captopril affinity chromatography. Comparison of trypsin-extracted and detergent-solubilized membrane-bound converting enzyme by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and isoelectric focusing indicated that the membrane-binding sequence contributed to a large extent to the size and charge of the enzyme. Both forms of the enzyme were glycoproteins but they differed in the glucidic content; 4.5% by weight of the enzyme in the trypsin-extracted ACE and 15% by weight of the enzyme in the detergent-solubilized ACE. In both cases hexoses were the most abundant residues. Both forms of the enzyme were found to contain 1 g-atom zinc/mol enzyme. The purified enzymes did not only split Hip-His-Leu but also AI and bradykinin. The Michaelis constant (Km) and maximum velocity (Vmax) values of the trypsin-extracted ACE for Hip-His-Leu were 52 x 10(-5) mol/l and 15.36 nmol/min respectively, and for AI they were 7.8 x 10(-5) mol/l and 0.45 nmol/min respectively. The Km and Vmax values of the detergent-solubilized ACE for Hip-His-Leu were 32 x 10(-5) mol/l and 11.75 nmol/min respectively, and for AI they were 6.5 x 10(-5) mol/l and 0.97 nmol/min.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of inter-stimulus interval on skin conductance responses and event-related potentials in a Go/NoGo task

Skin conductance responses (SCRs) to NoGo stimuli have been found to be smaller than to Go stimuli, possibly due to their diminished task relevance. These findings have been obtained at inter-stimulus intervals (ISI) that were unusually short for SCR recordings. Therefore, we tested whether the same findings would also hold at longer ISIs. Simultaneously, effects of ISI duration on the NoGo-N2 and-P3 components of event-related brain potentials (ERPs) were assessed. Go and NoGo stimuli were equiprobable while ISI varied between 2, 5, and 8 s. Although increasing the ISI-enhanced SCR amplitudes in general, it did not modulate the attenuation of the response to NoGo relative to Go stimuli. When considered as difference between NoGo and Go conditions, neither the NoGo-N2 nor the NoGo-P3 was affected by ISI variation. Together, these data confirm the feasibility of co-registering ERPs and SCRs.     

5-hydroxytryptamine induced relaxation in the pig urinary bladder neck

Background and purpose

5-Hydroxytryptamine (5-HT) is one of the inhibitory mediators in the urinary bladder outlet region. Here we investigated mechanisms involved in 5-HT-induced relaxations of the pig bladder neck.

Experimental approach

Urothelium-denuded strips of pig bladder were mounted in organ baths for isometric force recordings of responses to 5-HT and electrical field stimulation (EFS).

Key results

After phenylephrine-induced contraction, 5-HT and 5-HT receptor agonists concentration-dependently relaxed the preparations, with the potency order: 5-carboxamidotryptamine (5-CT) > 5-HT = RS67333 > (±)-8-hydroxy-2-dipropylaminotetralinhydrobromide > m-chlorophenylbiguanide > α-methyl-5-HT > ergotamine. 5-HT and 5-CT relaxations were reduced by the 5-HT₇ receptor antagonist (2R)-1-[(3-hydroxyphenyl)sulphonyl]-2-[2-(4-methyl-1-piperidinyl)ethyl]pyrrolidine hydrochloride and potentiated by (S)-N-tert-butyl-3-(4-(2-methoxyphenyl)-piperazin-1-yl)-2-phenylpropanamide dihydrochloride (WAY 100135) and cyanopindolol, 5-HT_1A and 5-HT_1A/1B receptor antagonists respectively. Inhibitors of 5-HT_1B/1D, 5-HT₂, 5-HT_2B/2C, 5-HT₃, 5-HT₄, 5-HT_5A and 5-HT₆ receptors failed to modify 5-HT responses. Blockade of monoamine oxidase A/B, noradrenergic neurotransmission, α-adrenoceptors, muscarinic and purinergic receptors, nitric oxide synthase, guanylate cyclase and prostanoid synthesis did not alter relaxations to 5-HT. Inhibitors of Ca²⁺-activated K⁺ and ATP-dependent K⁺ channels failed to modify 5-HT responses but blockade of neuronal voltage-gated Na⁺-, Ca²⁺-and voltage-gated K⁺ (K_v)-channels potentiated these relaxations. Adenylyl cyclase activation and cAMP-dependent protein kinase (PKA) inhibition potentiated and reduced, respectively, 5-HT-induced responses. Under non-adrenergic, non-cholinergic, non-nitrergic conditions, EFS induced neurogenic, frequency-dependent, relaxations which were resistant to WAY 100135 and cyanopindolol.

Conclusions and implications

5-HT relaxed the pig urinary bladder neck through muscle 5-HT₇ receptors linked to the cAMP-PKA pathway. Prejunctional 5-HT_1A receptors and K_v channels modulated 5-HT-induced relaxations whereas postjunctional K⁺ channels were not involved in such responses. 5-HT₇ receptor antagonists could be useful in the therapy of urinary incontinence produced by intrinsic sphincter deficiency.     

Human study of ion implantation as a surface treatment for dental implants

This clinical study evaluated a new surface treatment of ion implantation with CO ions which has previously been subjected to extensive study in animal models. The aim of this work was to assess its effect in humans. Experimental mini-implants were used; half of their longitudinal surface was machined and the other half was treated with CO ion implantation. The study was conducted in healthy volunteer patients who required prosthetic treatment with dental implants, and in accordance with the corresponding ethics committees. Coinciding with the insertion of commercial implants for oral restoration, one or two mini-implants were placed in the upper maxillary tuberosity or in the retromolar trigone of the mandible. The mini-implants were removed with a trephine jointly with a small volume of surrounding bone after a 3-month period. Two evaluation methods were used and both showed a greater degree of bone integration in the mini-implant section that underwent CO ion implantation treatment in comparison with the non-treated surface: 62.9% vs. 57.9%, and 54.8% vs. 46.2%. In addition, no adverse reactions were observed in the surface treatment with CO ion implantation. These results confirm the positive benefits in humans, based on the findings obtained from previous animal experiments.     

Consulta de atención primaria: ¿todo es del médico?

ObjectivesTo find out the proportion of primary healthcare consultations that could be attended by another professional other than the doctor.Designmulticentre cross-sectional study.LocationPrimary healthcare, west-gipuzkoa region, with 17 health centres taking part.ParticipantsReasons for consultation dealt with by 38 doctors over 5 days.Main measurementsAge, sex, frequency, category, initiative, reason for consultation and ideal level of healthcare.ResultsA total of 4,377 patients who generated 5,592 consultations were included. The average frequency was 10 visits/year. The large majority (93.1%) of consultations took place in the centre, 5.4% by telephone and 1.5% were home visits.A total of 74.4% of the consultations were requested, 17.2% arranged by the doctor, 6.4% arranged by protocol, 2% at the request of other professionals, and 8% were urgent.The reasons were; 71.5% (95% CI: 69.8-73.2) were medical clinical, 7.2% (6.2-8.2) minor symptoms, 18.4% (17.1-19.5) bureaucratic, and 2.9% (2.3-3.3) for information.The consultations for medical reasons accounted for 80.5% (79.3-81.7) and 19.5% (18.3-20.7) were for non-medical reasons. Non-medical reasons made up 29.3% of the telephone consultations, 20.2% of the consultations in the centre, and 2.4% of the home visits, as well as 16.7% of the urgent consultations.The ideal level of healthcare was considered to be doctor 80.7%, 13.2% nursing and 2.8% administrative. In the consultations for minor symptoms, nursing was considered the ideal level in 65.3% of cases.ConclusionsOne out of every 5 consultations could be dealt with by a professional other than the doctor, which in 5 hours of consultations would allow 1 hour to be gained which could be used for other activities.     

Analysis of ras DNA sequences in rat renal cell carcinoma

The DNA sequences for Ha-, Ki-, and N-ras were determined in six cell lines derived from independent rat hereditary renal cell carcinomas (RCC). Genomic regions encompassing codons 12, 13, and 61 of Ha-ras, Ki-ras, and N-ras, and codon 117 of Ha-ras were PCR amplified and directly sequenced. The DNA sequences of Ha-ras and Ki-ras were normal in all lines tested, as were the codon 12 and 61 sequences of N-ras. However, DNA sequence variations that could code for amino acid substitutions were observed in codons 13, 14, and 18 of N-ras in all the lines. The codon 13 Gly----Val alteration observed was consistent with activating N-ras mutations previously reported. When normal kidney DNA from rats with the hereditary tumor syndrome was sequenced, the same N-ras sequence variations observed in the tumor lines were found. DNA from outbred Long-Evans and inbred Fischer rats also had the altered N-ras sequences. The variant N-ras sequence was not observed in PCR-amplified N-ras cDNA from the RCC lines. Thus, tumor-associated activation of ras oncogene appears to be an infrequent event in spontaneous rat RCC. In addition, these data indicate that rats contain an N-ras DNA polymorphism that appears to be a species-specific anomaly.     

Improvements in pelvic exenteration: Factors responsible for reducing morbidity and mortality

Background: Since pelvic exenteration for the treatment of recurrent gynecologic malignancy first was described, reported rates of morbidity and mortality have declined steadily. However, the factors responsible for this decline have never been clearly delineated. Methods: We reviewed the charts of 154 patients who underwent pelvic exenteration for gynecologic malignancy between 1954 and 1994. Charts were abstracted for details of the surgical procedure, pathologic findings, postoperative management, short- and long-term complications, time to recurrence, and overall survival. Results: Seventy-two patients (47%) experienced 95 identifiable postoperative complications, resulting in death in 22 patients (14%). The rate of infectious complications declined to a statistically significant degree between the first two decades and latter two decades of the study (odds ratio [OR] 0.28, 95% CI 0.11–0.69). The use of routine prophylactic antibiotics was associated with this decline in infectious complications (OR 0.25, 95% CI 0.07–0.83). The use of preoperative subcutaneous heparin was associated with a reduction in thrombotic complications from 5 of 100 patients to 0 of 54 patients (P=.11), as well as a significant reduction in overall risk of complications (OR 0.53, 95% CI 0.33–0.85) and risk of postoperative mortality (OR 0.19, 95% CI 0.05–0.80). There was a significant reduction in overall risk of postoperative complications with both intensive care unit monitoring postoperatively (OR 0.65, 95% CI 0.43–0.99) and routine postoperative monitoring with a pulmonary artery catheter (OR 0.61, 95% CI 0.38–0.98). Conclusions: Routine use of prophylactic antibiotics, prophylactic subcutaneous heparin, and intensive postoperative monitoring appear to have reduced morbidity from pelvic exenteration.