Marfan Database (third edition): new mutations and new routines for the software.

The Marfan database is a software that contains routines for the analysis of mutations identified in the FBN1 gene that encodes fibrillin-1. Mutations in this gene are associated not only with Marfan syndrome but also with a spectrum of overlapping disorders. The third version of the Marfan database contains 137 entries. The software has been modified to accommodate four new routines and is now accessible on the World Wide Web at http://www.umd.necker.fr

A novel mutation in the neonatal region of the fibrillin (FBN)1 gene associated with a classical phenotype of Marfan syndrome (MfS). Mutations in brief no. 163. Online.

Marfan Syndrome (MfS) is an autosomal dominant inherited connective tissue disorder with variable phenotypic expression of cardiovascular, skeletal and ocular manifestations. Cardiovascular complications, such as aortic aneurysm and dissection drastically reduce life expectancy of individuals with MfS, whereas preventive surgery substantially improves the prognosis of these patients. A number of mutations in the fibrillin 1 (FBN1) gene associated with MfS have been identified to date, demonstrating considerable molecular heterogeneity. One region, however, located around exon 24, exhibits a striking clustering of mutations, which are associated with a severe, socalled neonatal form of MfS. Here we report the first mutation (G2950A) in exon 24 of the neonatal region of the FBN1 gene, associated with a classic MfS phenotype. The mutation leads to the subsitution of valin by isoleucin (V984I), both uncharged amino acids, which only differ in a single methyl group. This defect was identified in a proband with cardiovascular manifestations of MfS by SSCP analysis of PCR-amplified genomic DNA, direct PCR sequencing and RFLP analysis. The substitution was neither detected in the unaffected 4-year old daughter of the proband, nor in 3 of his healthy family members nor in 108 allels from control individuals, suggesting that this mutation is causative for MfS in the patient. Since no other family member of the proband is affected by MfS, the defect described is sporadic. In summary, we identified a novel defect in exon 24 of the neonatal region of the FBN1 gene in a patient with a classic phenotype of MfS, suggesting that conservative substitutions in this region may lead to a less severe phenotype of the disease. This finding further demonstrates the remarkable phenotypic heterogeneity associated with FBN1 mutations and stresses the significance of modifying genes and individual alterations in protein function for the pheontypic expression of the disease.

Glycerol-insulin raises circulating insulin antibodies in type I diabetic patients treated with permanently implanted devices.

The instability of insulin in the reservoirs of implantable insulin delivery devices has been a major obstacle in implementing this form of therapy. To overcome the problem of precipitation, a glycerol-insulin preparation has been used in large-scale long-term clinical trials. The aim of this study was to evaluate the stability of the glycerol-insulin solution and its effects on circulating insulin antibodies in eight type I diabetic patients who were implanted with an Infusaid pump (Infusaid Corporation, Norwood, MA) and followed for 1 year or more. Total insulin requirement did not change throughout the observation period. Plasma free insulin was higher during treatment with glycerol-insulin than with the standard insulin treatment (P less than .02). Insulin antibodies increased in all patients (P less than .05). High-performance liquid HPLC analysis of insulin samples from the pump reservoirs showed the generation of insulin modification products at a daily rate of 1.84%, reaching 40% to 50% of the total reservoir content 3 weeks after refilling; among these products, high molecular weight species accounted for about 15%. It is concluded that glycerol-insulin is not an adequate insulin preparation for use in implanted devices. Insulin deteriorated in the pump reservoirs, and insulin antibody concentration increased in the treated patients. It is believed that this antibody production is favored by circulating insulin fragments and polymers of insulin generated inside the pump reservoirs.

Stable insulin preparation for implanted insulin pumps. Laboratory and animal trials.

The stability and longevity of the polyethylene-polypropylene glycol-stabilized insulin have been tested in vitro and in vivo in an implanted insulin-infusion device, the programmable implantable medication system (PIMS). In vitro tests demonstrated long-term compatibility with refill cycles of up to 3 mo, with a preparation of 400 U/ml. Total test period in vitro was 3.2 device-yr (combined time of device use). Insulin retained 88-93% native structure. A major modification, which was biologically active and nonimmunogenic, was identified and partially characterized. Examination of one device by scanning electron microscopy and X-ray microanalysis after 1 yr of insulin infusion revealed surfaces clean of insulin precipitate or other material along the entire insulin-delivery pathway. Surface analysis of the silicone-lined polyethylene catheters after 6 mo of infusion also showed no evidence of major insulin precipitate. In vivo stability trials were accomplished with PIMS implanted in diabetic dogs with an intraperitoneal delivery site. There has been no insulin blockage of the catheter of active pumps after 5.1 dog-yr (combined time of trials) of trials (up to 5 mo between refills in a single dog). Structural stability of insulin was analyzed by high-performance liquid chromatography. On average, 90.8% of the insulin sampled from the reservoir in vivo was native insulin, with an average of 96.2% retention of active forms.

Fingerprint analysis of insulin and proinsulins.

Proteolysis of insulin or (pre)proinsulin with S. aureus protease V8 in Tris buffer at neutral pH yields a characteristic pattern of peptide fragments that is resolved using high-performance liquid chromatography. Identification of the fragments of interest was achieved by comparison of insulins of different species, of modified insulins and of proinsulin and N-extended proinsulin, and by amino acid analysis. The fingerprint method allows, for example, the simultaneous analysis of porcine and human insulin, the identification of a modified insulin generated in dosing devices, as well as the individual analysis of the two disulfide linkages between the A- and B-chain in refolded insulins.

Chemical stability of insulin in a delivery system environment.

Exposure of insulin solutions to elevated temperatures for prolonged periods of time will inevitably lead to chemical modifications of the hormone. Contact with different materials in dosing devices, other design-related factors and motion appear to be chemically more detrimental than storage in glass vials at the same temperature. An in vitro test, designed to mimic the in vivo situation, consisted of delivery of insulin at 37 degrees C while the device was constantly moved on a shaking apparatus. Insulin quality was assessed using high performance liquid chromatography. A polyethylenepolypropylene glycol-stabilized neutral human insulin solution (HOE 21 PH) was used. A single insulin derivative is the major modification product which, after passage of the complete infusion system, amounts to up to 10%. The biological potency of the derivative is indistinguishable from native insulin. Delivery of acidic insulin under implant conditions, leads to extensive and multiple insulin derivatization, even though the biological potency remains 95% after 4 weeks.

[Medical performance record of emergency physicians' mobile unit and emergency aid helicopter]. / Einsatzprotokoll für Notarztwagen und Rettungshubschrauber.

A large amount of data and information has accumulated in the course of the ever-increasing rate of first-aid relief by emergency physicians. These data have either not been documented so far or, if so, in a rather perfunctory manner. For this reason, the authors developed for the Mannheim emergency physician's mobile car unit and for the first-aid relief helicopter Christoph 5, a record of performance (logbook) of primary-care cases for the purpose of data acquisition and computer-assisted medical documentation and statistics via EDP. An example of an E-605 intoxication serves to illustrate the advantages of this logbook, which has already been applied to more than 200 emergency cases.

Thermal stability and protein structure.

Amino acid sequences have been compared for thermophilic and mesophilic molecules of ferredoxin, glyceraldehyde-3-phosphate dehydrogenase, and lactate dehydrogenase. It is shown that Gly, Ser, Ser, Lys, and Asp in mesophiles are generally substituted by Ala, Ala, Thr, Arg, and Glu, respectively, in thermophiles. These exchanges suggest that thermal stability can be achieved by the addition of many small changes throughout the molecule without significant change in the backbone conformation. Their overall effect is primarily to increase internal and decrease external hydrophobicity as well as to favor helix stabilizing residues in helices. These substitutions minimize interruption of function or internal residue packing arrangements. Although the analysis has been confined to the above-mentioned molecules, the observed stabilizing principles may be more generally applicable.

Combined coenzyme-substrate analogues of various dehydrogenases. Synthesis of (3S)- and (3R)-5-(3-carboxy-3-hydroxypropyl)nicotinamide adenine dinucleotide and their interaction with (S)- and (R)-lactate-specific dehydrogenases.

Two diastereomeric nicotinamide adenine dinucleotide (NAD+) derivatives were synthesized in which the substrates of (S)-and (R)-lactate-specific dehydrogenases are covalently attached via a methylene spacer at position 5 of the nicotinamide ring. The corresponding nicotinamide derivatives were obtained stereospecifically by enzymatic reduction of 5-(2-oxalylethyl)nicotinamide. (3S)-5-(3-Carboxy-3-hydroxypropyl)-NAD+ undergoes and intramolecular hydride transfer in the presence of pig heart lactate dehydrogenase, forming the corresponding coenzyme-substrate analogue composed of pyruvate and NADH. No cross-reaction products resulting from an intermolecular reaction are observed. Two (R)-lactate specific dehydrogenases, however, do not catalyze a similar reaction in either one of the two diastereomers. A possible arrangement of the substrates in the active centers of these enzymes is proposed. 5-Methyl-NAD+ and 5-methyl-NADH are active coenzymes of pig heart lactate dehydrogenase in contrast to reports in the literature. (S)-Lactate binds to this enzyme in the absence of coenzyme, exhibiting a dissociation constant of 11 mM.