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A Bonet

Publications and source records attributed to A Bonet.

27 records · Page 2Linked to original sources
PubMed1988

The internal crosslinking of the S1 heavy chain from smooth muscle probed by dibromobimane.

The reaction of the crosslinker dibromobimane has recently revealed a functionally important internal loop structure within the skeletal myosin S1 heavy chain where Cys-522 of the 50K domain and Cys-707 (SH1) of the 20K region are spatially juxtaposed. Here we have studied the possible relevance of this topological feature to the architecture and transducing activity of the myosin head in general, by extending the dibromobimane modification to smooth muscle myosin. Treatment of chicken gizzard myosin S1 with dibromobimane resulted in intramolecular crosslinking between the C-terminal 25K and central 50K segments of the S1 heavy chain. The data suggest a conservation at the 50K-25K interface of smooth muscle S1 heavy chain and the importance of the neighboring SH1 region, whose conformation may play an important role in energy transduction by the myosin head.

Adenosine Triphosphatases↗
PubMed1987

Comparative structure of the protease-sensitive regions of the subfragment-1 heavy chain from smooth and skeletal myosins.

The heavy chain fragments generated by restricted proteolysis of the smooth chicken gizzard myosin subfragment-1 (S-1) with trypsin, Staphylococcus aureus V8 protease, and chymotrypsin were isolated and submitted to partial amino acid sequencing. The comparison between the smooth and striated muscle myosin sequences permitted the unambiguous structural characterization of the two protease-vulnerable segments joining the three putative domain-like regions of the smooth head heavy chain. The smooth carboxyl-terminal connector is a serine-rich region located around positions 632-640 of the rabbit skeletal sequence and would represent the "A" site that is conformationally sensitive to the myosin 10 S-6 transition and to its interaction with actin (Ikebe, M., and Hartshorne, D. J. (1986) Biochemistry 25, 6177-6185). A third site which undergoes a nucleotide-dependent chymotryptic cleavage which inactivates the Mg2+-ATPase (Okamoto, Y., and Sekine, T. (1981) J. Biochem. (Tokyo) 90, 833-842, 843-849) was identified at Trp-31/Ser-32. It is vicinal to Lys-34 that is monomethylated in the skeletal heavy chain but not at all in the smooth sequence. However, the two trimethyl lysine residues present in the skeletal sequence are conserved in the same regions of the smooth S-1 and may play a general functional role in myosin. The smooth central 50-kDa segment could be selectively destroyed by a mild tryptic digestion in the absence of any unfolding agent, with a concomitant inhibition of the ATPase activities. This feature is in line with the proposed domain structure of the S-1 heavy chain and also suggests a relationship between the specific biochemical properties of the smooth S-1 and the particular conformation of its 50-kDa region.

Amino Acid Sequence↗
PubMedDate not supplied

[Rational prescribing and cost reduction in the treatment of arterial hypertension: a simulation exercise].

INTRODUCTION: Cost of antihypertensive drugs in Spain raises 100.000 millions of pesetas. The utilization of new drugs more expensive than classics diuretics and beta blockers is the main reason of this cost increase.The Joint National Commission on Hypertension 6th Report supports the utilization of diuretics and beta blockers as the first choice in patients without any special condition, based in their best efficience. Other professional group don't point out any therapeutic drugs because each of them have their indication. Health authorities have implemented measures intended more to achieve savings than to improve prescriptions. There are not any studies which demonstrate that the second type of measures are more efficient than first one. AIM: To realize an economic evaluation, of a program of blood hypertension treatment taking and not taking into account the The Joint National Commission on Hypertension 6th Report. METHODS: Descriptive, prescription-indication study. Cost minimization. Health center from Valencia (Spain). Three hundred and thirteen patients were studied, randomly selected. Three strategy of cost decrease were considered: a) same prescription profile using the cheapest drugs, b) change of profile taken into account JNC-VI recommendations using the original drugs, and c) second option, but using the cheapest drugs. RESULTS: Ninety seven percent of diuretics had specific indications, 84% of beta blockers, 64.5% of IECAS, 31.6% of alfa blockers and 13% de calcium channel blockers. Diuretics were counter-indicated in 3.5% of patients, beta blockers in 10.5%, and both in 3.1%. Total cost of the unmodifed prescription was 12.412.839 pesetas, cost of the first strategy was 10.067.107, of the second 5.311.783 pesetas and of the third 1.999.094 pesetas. CONCLUSIONS: Our prescription profile don't follow JNC VI recommendations and this is not justified on indications or counterindications of diuretics and beta blockers. Following JNC VI is more efficient than looking only for the cheapest drug.

Aged↗
PubMedDate not supplied

[Multicenter study on incidence of total parenteral nutrition complications in the critically-ill patient. ICOMEP study. Part I].

OBJECTIVE: To assess parenteral nutrition complications in a prospective cohort of patients admitted to the ICU. MATERIAL AND METHODS: Prospective, multicenter study of patients admitted to the ICU and that received total parenteral nutrition (TPN). A 14-item questionnaire was done. Total number of admissions and TPN-treated patients were recorded. Demographical data, diagnosis, APACHE II, multiorgan dysfunction index and TPN indications were included. Each complication was previously defined and was related to the route, administration, serum electrolytes unbalances, active ingredients, liver dysfunction, and nosocomial infections. An independent group managed the databases. Data were expressed in absolute values or by their median and percentile (25-75). The rate and incidence density of complications are determined. RESULTS: The number of admissions during the study period was 3409. Three hundred and seventy (11%) were valid cases that were treated with PN. Two hundred and thirty seven were men, 142 patients were admitted for medical causes, 195 for surgical causes and 33 for trauma. One hundred and twenty patients were moderately or severely underfed, 181 received PN for 7 days (3-11), and 189 received PN and EN. The main indication for PN was paralytic ileus, in 145 patients. TPN was withdrawn for switching to EN in 121 cases and for complications in 5 cases. PN summed up 3220 days. The incidence of complications was: access route 9.32%, maintenance 19.7% and 0.8 per 100 days. Administration, 5.6% and 6.4 per 100 days. Nutrients, 94.3% and 10.8 per 100 days. Catheter-induced sepsis, 54.6% and 0.44 bacteriemias per 100 days with catheter. Nosocomial infection, 54.6% and 6.27 per 100 days on TPN. CONCLUSIONS: hyperglycemia and liver dysfunction have a greater incidence. Hyperglycemia, electrolyte unbalances and catheter complications have a greater number of therapeutic interventions, but does not mean that TPN should be withdrawn.

Aged↗
PubMedDate not supplied

[Multicenter study on incidence of total parenteral nutrition complications in the critically-ill patient. ICOMEP study. Part II].

OBJECTIVE: To assess enteral nutrition complications in a prospective cohort of patients admitted to the ICU. MATERIAL AND METHODS: Prospective, multicenter study of patients admitted to the ICU and that received enteral nutrition (EN). Demographical data, main diagnosis, and nutritional and severity indexes were included. Complications were previously defined and were categorized as gastrointestinal or infectious. An independent group managed the databases and performed the statistical analysis. Data were expressed in absolute values or by their median and percentile (25-75). The rate and incidence density of complications and the odds ratio for complications were determined. RESULTS: 544 out of 3409 patients received enteral nutrition. Three hundred and three patients were admitted for medical causes, 149 for surgical causes and 92 for trauma. Ninety nine patients were underfed, and the nutritional risk index was 69.7. The incidence of gastrointestinal complications was 6 episodes per 100 days of nutrition, and in 89 patient they resulted in enteral nutrition withdrawal. Early enteral nutrition did not yield more complications than late EN. Vomiting was more frequent in late EN (OR 0.4; 95%CI: 0.2-0.7). Temporary withdrawal of diet in 140 patients was the most used procedure, which resulted in a lower caloric intake (median of 2 kcal/kg/d) than programmed. Nosocomial infection rates were 7.47% for catheter-induced sepsis and 51% for other nosocomial infections, and 35% developed pneumonia. CONCLUSIONS: Gastrointestinal complications with enteral nutrition are frequent, result in insufficient caloric intake and definitive withdrawal of diet in a significant number of cases. Early enteral nutrition is not associated with an increased number of complications. Episodes of increase of the gastric residue do not increase the incidence of pneumonia. Other infectious complications are within the range of what has been published and seem to be little modified by the use of enteral nutrition.

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