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Biomedical subjects

F Maisano

Publications and source records attributed to F Maisano.

27 records · Page 2Linked to original sources
PubMed1995

[Combined valve repair for mitral-aortic insufficiency].

Reconstructive surgery is considered the best treatment of mitral insufficiency. Aortic valvuloplasty has been used only rarely in the past for the treatment of aortic insufficiency. Between October 1994 and November 1994, two patients admitted at our institution with the diagnosis of mitral and aortic insufficiency have been successfully submitted to combined valvuloplasty. Although long term results of aortic reconstruction are unavailable, short-term and middle-term results are satisfactory and warrant conservative surgery in selected cases. Aortic repair is an attractive option especially in those patients with combined aortic insufficiency and mitral disease suitable for valvuloplasty.

Aortic Valve Insufficiency↗
PubMed1993

Dynamic cardiomyoplasty as an effective therapy for dilated cardiomyopathy.

Nine male patients with dilated cardiomyopathy unresponsive to maximal medical therapy were submitted to dynamic cardiomyoplasty according to the technique described by Carpentier and Chachques, and preliminary postoperative results are reported. Seven patients were in New York Heart Association (NYHA) Class III and two were in intermittent Class IV. The mean age was 56 years (range 51 to 61 years). Preoperative ejection fraction (EF) by multiple gated acquisition ranged from 14% to 28% (mean 20.7%). No additional surgery was performed. Transesophageal echocardiographic monitoring was used during surgery to guide the wrapping procedure. There was no operative mortality. There was one early death (1 month). One late death (sudden death) occurred 7 months after surgery despite significant clinical improvement. Follow-up ranges from 2 to 16 months. Six patients were submitted to hemodynamic evaluation from 4 to 6 months after surgery by transthoracic and transesophageal echo-Doppler assessment. Effective latissimus dorsi support was clearly documented in all patients by comparing postoperative basal hemodynamic values (Cardiomyostimulator [Medtronic, Inc.] switched off) and data obtained during assisted beats (EF increased from 19.4% +/- 8.6% to 32.6% +/- 13.8%, p = 0.043; and stroke volume increased from 51.6 +/- 20.6 mL to 63.0 +/- 22.0 mL, p = 0.014). All patients who completed the latissimus dorsi training protocol were in NYHA Class I or II. A significant reduction in postoperative medical therapy was achieved in all patients. Our preliminary results confirm that the cardiomyoplasty procedure is to be considered a safe and valuable mean for treating selected patients with dilated cardiomyopathy refractory to maximal pharmacological treatment.

Assisted Circulation↗
PubMed1991

A new human growth hormone production process using a recombinant Bacillus subtilis strain.

We constructed a series of hybrid plasmids which directed the synthesis of different human growth hormone (hGH) precursor sequences in Bacillus subtilis. In addition to the 191 amino acids of the hormone, the precursors had in common an amino-terminal extension characterized by the presence of a methionine at position 1 and of the tetrapeptide Ile-Glu-Gly-Arg preceding the first residue (Phe) of hGH. The sequence between the methionine and the tetrapeptide was specific for each precursor and, because of the presence of charged residues, conferred particular properties to the molecules. Long homopolymeric tail-containing precursors such as MRRRRRRIILM-IEGR appeared insoluble whereas shorter sequences of the type MRR-IEGR and MEELM-IEGR augmented the solubility of the precursors with respect to Met-hGH. The soluble precursors could be easily purified from the bulk proteins taking advantage of the charged residues present on the N-terminal tail. After purification, the natural hGH was obtained by treating the precursors with the protease Factor Xa which cleaves after the arginine residue of the tetrapeptide IEGR. A protocol for the production and purification of authentic hGH from a strain expressing one of these soluble precursors is reported.

Amino Acid Sequence↗
PubMed1985

Thiophilic adsorption--a new method for protein fractionation.

Divinylsulphone-activated agarose to which mercaptoethanol is coupled showed very selective group adsorption of human serum proteins, in particular the immunoglobulins. The adsorption increases markedly in the presence of high concentrations of neutral water-structure forming salts and is distinct from adsorptions based on hydrophobic interaction. A characteristic feature of this new type of adsorbent is the structure of the groups attached to the polymer, P, i.e., R-S-CH2-CH2-SO2-CH2-CH2-O-P, where R is a small aliphatic residue. Our results indicate that the thioether sulphur and the adjacent sulphone group act cooperatively and are apparently necessary to maintain the distinct behaviour of such absorbents.

Adsorption↗
PubMed1985

Synthesis of new hydrophobic adsorbents based on homologous series of uncharged alkyl sulphide agarose derivatives.

A homologous series of uncharged thioalkyl derivatives of agarose were prepared by a simplified synthetic route and their adsorption behaviour towards human serum proteins was evaluated and compared with that of a commercially available alkyl ether derivative of agarose. The influence of the spacer arm length on the adsorption efficiency was also investigated. The degree of substitution of the derivatives can be estimated conveniently by sulphur analysis. The four different types of thiolkyl derivatives (C6, C8, C12 and C14) investigated here behave in all respects like hydrophobic adsorbents. The coupling yield obtained is high (75% or more) and is better than that obtained by alternative synthetic routes reported so far. The adsorption capacity towards serum proteins of the various derivatives increases with increasing alkyl chain length and degree of substitution. Desorption is achieved by a progressive decrease in the polarity of the eluent and the recovery of the applied material is in the range 80-90%. The role played by the thioether as a possible modulator of the observed hydrophobic adsorption is discussed. For the group separation of serum proteins the optimum adsorbent, as regards capacity combined with ease of elution of adsorbed material, should be substituted with chains of six or eight carbon atoms and have a ligand concentration in the range 80-120 mumole g-1 dry gel.

Adsorption↗
PubMedDate not supplied

Coupling of DTPA to proteins: a critical analysis of the cyclic dianhydride method in the case of insulin modification.

The reaction between the cyclic dianhydride of diethylenetriaminepentaacetic acid (DTPA), a bifunctional reagent, and proteins under various conditions was studied using porcine insulin as a model protein. The reaction was compared with that between citraconic anhydride, a monofunctional reagent, and insulin. Products were characterized chromatographically and electrophoretically before and after deesterification by hydroxylamine. A DTPA-conjugated product was further characterized by proteolytic fragmentation. The reaction with citraconic anhydride yielded the expected number of products exclusively acylated on amino groups. In contrast, the reaction with the cyclic dianhydride of DTPA under all conditions examined yielded a much higher number of products than expected. Among the products formed were O-acylated ones and products of intermolecular cross-linking. It is concluded that the use of the cyclic dianhydride of DTPA does not allow the reliable preparation of proteins or other macromolecules conjugated with a high number of DTPA molecules in which each molecule of DTPA is linked to one amino group of the macromolecule through a single amide bond.

Anhydrides↗
PubMedDate not supplied

Diagnosis and management of cerebral malperfusion phenomena during aortic dissection repair by transesophageal Doppler echocardiographic monitoring.

BACKGROUND: Early diagnosis and surgical decision making are the key for survival in acute type A aortic dissection (AAD-A). As such, transesophageal echocardiography (TEE) is widely accepted tool in the diagnosis of AAD-A. METHODS: We used TEE in 49 cases as the sole diagnostic examination of AAD-A since November 1989. It was particularly useful intraoperatively to detect cerebral malperfusion during AAD-A repair. We were able to accurately monitor the blood flow of the aortic arch by using TEE for all patients throughout the operation. Only two patients developed severe cerebral malperfusion after the distal anastomosis was finished under deep hypothermic circulatory arrest. TEE showed that the malperfusion after the bypass was re-established. In both cases the expanded false lumen blocked the true lumen. We immediately switched the perfusion cannula from the femoral artery to the ascending aortic graft to create antegrade flow. RESULTS: The subsequent TEE showed only the flow in the true lumen. One patient recovered without any complication while the other suffered mild, temporary neurological defects. Cerebral malperfusion is a potential catastrophic complication of AAD-A, which may exist before surgery or be caused by the operation itself. CONCLUSIONS: We recommend continuous intraoperative TEE to monitor aortic arch flow during these operations. This allows immediate detection of cerebral malperfusion and prompt action can be taken to prevent irreversible brain damage.

Adult↗
PubMedDate not supplied

An effective technique to correct anterior mitral leaflet prolapse.

Up to one-third of the patients with degenerative mitral valve disease and severe mitral regurgitation have anterior mitral valve prolapse due to chordal rupture or elongation. Surgical treatment of such a condition is often technically demanding and not infrequently associated with suboptimal results. Techniques used to treat anterior leaflet prolapse include chordal transfer, chordal shortening, artificial chordae, and anterior leaflet resection or plication. Each of these strategies has potential shortcomings, and there is considerable controversy concerning the durability of anterior leaflet prolapse repairs using these techniques. The "edge-to-edge" technique, a simple and effective method of correcting anterior mitral leaflet prolapse is described.

Chordae Tendineae↗