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Biomedical subjects

M Mares

Publications and source records attributed to M Mares.

At least 19 recordsLinked to original sources
PubMed2005

Predictive factors for spondylotic cervical myelopathy treated conservatively or surgically.

A prospective 3-year randomized study comparing conservative and surgical treatment of spondylotic cervical myelopathy to establish predictive factors for outcome after conservative treatment and surgery. The clinical, electrophysiological and imaging parameters were examined to reveal how they characterized the clinical outcome. The patients with a good outcome in the conservatively treated group were of older age before treatment, had normal central motor conduction time (CMCT), and possessed a larger transverse area of the spinal cord. The patients with a good outcome in the surgically treated group had a more serious clinical picture (expressed in mJOA score and slower walk). Patients should rather be treated conservatively if they have a spinal transverse area larger than 70 mm2, are of older age and have normal CMCT. Surgery is more suitable for patients with clinically worse status and a lesser transverse area of spinal cord.

Adult↗
PubMed2005

Predictive factors for mild forms of spondylotic cervical myelopathy treated conservatively or surgically.

A prospective 3-year randomized study comparing conservative and surgical treatment of spondylotic cervical myelopathy to establish predictive factors for outcome after conservative treatment and surgery. The clinical, electrophysiological and imaging parameters were examined to reveal how they characterized the clinical outcome. Statistically, pair-wise and multiple comparisons of different were used with the independent t-test and on one-way anova models followed by Tukey multiple-range tests. The patients with a good outcome in the conservatively treated group were of older age before treatment, had normal central motor conduction time (CMCT), and possessed a larger transverse area of the spinal cord. The patients with a good outcome in the surgically treated group had a more serious clinical picture (expressed in mJOA score and slower walk). Patients should rather be treated conservatively if they a spinal transverse area larger than 70 mm2, are of older age, and have normal CMCT. Surgery is more suitable for patients with clinically worse status and a lesser transverse area of spinal cord.

Adult↗
PubMed2001

Ontogeny constrains systemic protease inhibitor response in Nicotiana attenuata.

Protease inhibitors (PIs) are plant compounds that can inhibit proteases of mammal, insect, or pathogen origin and are frequently induced by mechanical wounding, insect feeding, or pathogen infection. Nicotiana attenuata is a species that induces nicotine, volatiles, and phenolics in response to damage. Here we examine the distribution of PIs in N. attenuata to determine if they are part of the induced response in this species and if this response is ontogenetically constrained. We found that N. attenuata shoot extracts inhibited trypsin (Tryp) and chymotrypsin (Chym) activities, while root extracts inhibited Tryp, Chym, and the bacterial protease subtilisin (Sub). The highest TrypPI levels were found at midday in the source-sink transition leaf, while older or younger leaves contained lower TrypPI levels and did not show significant diurnal fluctuations. Rosette plants, bolting plants, and flowering plants all contained TrypPIs in leaves, stems, and flowers, while seed capsules, seeds, and young seedlings did not contain any PIs. PIs in N. attenuata rosette plants were induced by Manduca sexta larval feeding, methyl jasmonate (MeJA) treatment, wounding, and application of M. sexta oral secretion and regurgitant. The response to MeJA application was stronger and longer lasting than to mechanical wounding. The direction and magnitude of the systemic response to mechanical wounding or larval damage depended on the age of the leaf that was damaged and the frequency of wounding. The systemic signal for TrypPI induction appears to follow source-sink relations in the plant and to be regulated by the octadecanoid pathway. Interestingly, by the time plants reach the flowering stage, they had lost the ability to increase PI levels after MeJA treatment. We concluded that plant ontogeny constrains both constitutive and inducible PI production in N. attenuata.

Acetates↗
PubMed2000

Arginine-based structures are specific inhibitors of cathepsin C. Application of peptide combinatorial libraries.

Novel synthetic peptide inhibitors of lysosomal cysteine proteinase cathepsin C have been designed through the use of soluble peptide combinatorial libraries. The uncovered structural inhibitory module consists of the N-terminal cluster of L-arginine residues. Its modification with D-amino acids or arginine derivatives did not increase the inhibition strength. Inhibitory potency of oligoarginines improves with the elongation of peptide chain reaching a maximum for octa-L-arginine. The oligoarginines specifically interact with the cathepsin C active site as shown by competitive-type inhibition kinetics (Ki approximately 10-5 M) and intrinsic fluorescence measurements. The inhibitory interaction of oligoarginines is established through the specific spatial contact of a net of guanidino groups in the arginine side-chains, as indicated by comparison with inhibitory action of low molecular mass guanidine derivatives (Ki approximately 10-3 M). Nonarginine polyionic compounds cannot mimic the inhibitory effect of oligoarginines. The arginine-based peptide inhibitors were selective towards cathepsin C among other cysteine proteinases tested.

Animals↗
PubMed2000

Characterization of interaction of gH and gL glycoproteins of varicella-zoster virus: their processing and trafficking.

Varicella-zoster virus (VZV) glycoproteins gH and gL were examined in a recombinant vaccinia virus system. Single expression of glycoprotein gL produced two molecular forms: an 18 kDa form and a 19 kDa form differing in size by one endoglycosidase H-sensitive N-linked oligosaccharide. Coexpression of gL and gH resulted in binding of the 18 kDa gL form with the mature form of gH, while the 19 kDa gL form remained uncomplexed. The glycosylation processing of gL was not dependent on gH; however, gL was required for the conversion of precursor gH (97 kDa) to mature gH (118 kDa). Subsequent analyses indicated that gL (18 kDa) was a more completely processed gL (19 kDa). Screening of the culture media revealed that gH and gL were secreted, but only if coexpressed and complexed together. The secreted form of gL was 18 kDa while that of gH was 114 kDa. The fact that secreted gH was smaller than intracytoplasmic gH suggested a proteolytic processing event prior to secretion. The 19 kDa form of gL was never secreted. These findings support a VZV gL recycling pathway between the endoplasmic reticulum and the cis-Golgi apparatus.

Biological Transport↗
PubMed2000

Off label and unlicensed drug use among French office based paediatricians.

AIMS: To determine the extent of off label and unlicensed drug use in French office based paediatric practice. METHODS: A prospective one day survey of all written prescriptions, for patients under 15 years, among 95 office based paediatricians in the Paris, France metropolitan area. Main outcome measures were: comparison of the use of each drug with its product licence for age, indication, dose, and route of administration. RESULTS: A total of 2522 prescriptions were administered to 989 patients; 844 (33%) were used either in an unlicensed (4%) or an off label (29%) manner. A total of 550 (56%) paediatric patients received one or more off label prescriptions. CONCLUSIONS: Off label prescriptions (that is, outside the terms of the Summary of Product Characteristics) are widespread in office based paediatric practice, while unlicensed drug use is rare in our study. New regulations in the licensing process in Europe are needed to allow children to receive drugs that have been fully evaluated in their specific age group.

Adolescent↗
PubMed1994

Multiple functions of pro-parts of aspartic proteinase zymogens.

The importance of aspartic proteinases in human pathophysiology continues to initiate extensive research. With burgeoning information on their biological functions and structures, the traditional view of the role of activation peptides of aspartic proteinases solely as inhibitors of the active site is changing. These peptide segments, or pro-parts, are deemed important for correct folding, targeting, and control of the activation of aspartic proteinase zymogens. Consequently, the primary structures of pro-parts reflect these functions. We discuss guidelines for formation of hypotheses derived from comparing the physiological function of aspartic proteinases and sequences of their pro-parts.

Amino Acid Sequence↗
PubMed1994

Report on a 3-year follow-up zidovudine (AZT) treatment in a group of HIV-positive patients with congenital clotting disorders.

Eleven (50%) of 22 HIV-seropositive patients suffering from congenital coagulation defects and followed at the Hemophilia Center of Padua met the eligibility criteria for zidovudine (AZT) therapy. A 3-year clinical and laboratory follow up is described. Mean length of AZT treatment was 14.3 +/- 11 months. Three patients were enrolled at the latest stages (CDC stage IV) of HIV disease. They showed no clinical improvement after AZT administration and died with AIDS. One CDC stage III patient died from a high-grade non-Hodgkin's lymphoma (NHL) which suddenly developed 3 months after starting AZT. Seven patients began antiretroviral treatment when they were mild or asymptomatic for HIV infection (CDC stage II and III). None developed any sign of HIV disease progression on the basis of CDC criteria. Moreover, AZT administration induced an improvement of the humoral markers related to HIV disease, as CD4 T-lymphocyte count, serum beta 2-microglobulin (B2M) and, although only for few months, neopterin (Np) levels. A mild thrombocytopenia due to HIV infection was detected in 5 patients. In all cases AZT treatment was effective in increasing and/or normalizing the platelet count. Reduced daily dose AZT (600-500 mg/day) appeared to be well tolerated and of minimal toxicity as compared to the higher dose (1200 mg/day). In our study, the zidovudine-induced bone marrow suppression, namely severe anemia or pancytopenia, was the major side-effect limiting tolerance of the higher dose AZT.

Adolescent↗
PubMed1993

Synthesis of phosphorylated oligosaccharides in lysozyme is enhanced by fusion to cathepsin D.

Chinese hamster ovary cells transfected with human lysozyme cDNA encoding Asn instead of Gly22 synthesize a mutant lysozyme, [Asn22]lysozyme, with about 60% of the molecules bearing carbohydrate. This carbohydrate is predominantly of the complex type and contains a varied number of lactosamine repeats. In this study we show that the glycosylation of [Asn22] lysozyme fused to human cathepsin D is altered relative to [Asn22]lysozyme alone. The fusion protein is synthesized as a 66-kDa precursor that is cleaved to enzymatically active and antigenically positive cathepsin D and lysozyme. As compared with [Asn22]lysozyme the lysozyme moiety of the fusion protein shows an increased N-glycosylation and a decreased synthesis of lactosamine repeats. Cleavage of the precursor with cathepsin L has revealed that the lysozyme portion of the secreted fusion protein bears a complex type carbohydrate. The intracellularly released lysozyme portion of the fusion protein contains trimmed oligosaccharides. In the presence of NH4Cl the lysosomal targeting of the fusion protein is inhibited. The secreted protein is then enriched in molecules bearing phosphorylated high mannose oligosaccharides in their lysozyme moiety. Our results indicate that carbohydrate processing in [Asn22]lysozyme, including the synthesis of mannose 6-phosphate residues and of lactosamine repeats, is altered by the attached cathepsin D. The phosphorylation of the carbohydrate on the lysozyme portion results in a very efficient lysosomal targeting of the concerned fusion protein molecules.

Animals↗
PubMed1993

The importance of serial immunoglobulin evaluations in HIV-seropositive haemophiliacs.

The aim of our investigation was to evaluate whether the alteration of immunoglobulins (Igs) may be a predictive marker of the evolution of HIV infection in seropositive haemophiliacs. For this purpose two groups of haemophiliac patients (16 seronegative and 21 seropositive) were compared to evaluate the variations of the Ig profile over a period of 5 years (1985-1989). The two populations were similar for the number of transfusions of blood products and for the severity of post-transfusional hepatic disorders. The IgM increase, in the first stages of HIV infection, appears to be more discriminant than polyclonal elevation of IgG, which is already present in seronegative polytransfused haemophiliac patients.

Biomarkers↗
PubMed1993

Bleeding as a cause of death in HIV-seropositive patients with congenital clotting disorders.

The causes of death in a group of HIV-seropositive patients suffering from congenital clotting disorders (cCD) were studied. During the past 6 years, we have followed 19 patients with cCD and HIV infection. Eight patients fulfilled revised CDC criteria for AIDS, 6 subjects reached stage III of CDC, and 5 remained asymptomatic (CDC stage II). All patients who developed AIDS died. In 5 patients, the terminal cause of death was a severe haemorrhage (hematemesis, melena or haemoptysis) after gastrointestinal or lung opportunistic infections. Two other patients died as a consequence of disseminated infections but without significant bleeding. Only one subject died due to neoplastic disease. In the first stages of CDC (II and III), no increase in bleeding symptoms were seen in cCD HIV infected patients. The risk of haemorrhages is, however, increased in AIDS patients. Adequate replacement therapy should be started early whenever severe opportunistic infections appear.

AIDS-Related Opportunistic Infections↗
PubMed1992

New trypsin inhibitors are present in the coelomic fluid of the earthworm Lumbricus terrestris.

Proteinase-inhibiting components of the coelomic fluid of the earthworm Lumbricus terrestris were examined. Inhibition of proteinases of serine, aspartate and thiol families was tested. Very strong inhibition was observed only in the case of trypsin. Additional data suggest that the inhibition is related to proteins of molar mass of 42 kDa and 20 kDa, respectively. These two proteins are present in the coelomic fluid in several forms which differ in their isoelectric points.

Animals↗
PubMed1991

Inhibition of aspartic proteinases by propart peptides of human procathepsin D and chicken pepsinogen.

Two propart peptides of aspartic proteinases, the propart peptide of chicken pepsin and human cathepsin D, respectively, were investigated from the point of view of their inhibitory activity for a set of aspartic proteinases. These peptides display a very broad inhibitory spectrum. The strongest inhibition was observed for pepsin A-like proteinases where propart peptides can be used as titrants of active enzymes.

Animals↗
PubMed1991

Crystallization and preliminary crystallographic study of cathepsin D inhibitor from potatoes.

Single crystals of the glycosylated inhibitor of cathepsin D and trypsin isolated from potato tubers were obtained using the hanging drop vapor diffusion method and ammonium nitrate as precipitant. The crystals exhibit strong F222 pseudo symmetry but belong to the orthorhombic space group C222 or C222(1), with cell parameters a = 73.8 A, b = 119.9 A and c = 133.2 A with two molecules per asymmetric unit. The crystals diffract to a resolution of 2.4 A.

Cathepsin D↗
PubMed1991

Prevalence of HIV infection in a cohort of patients with congenital coagulation defects of the prothrombin complex factors.

Twenty-seven patients suffering from congenital coagulation defects of the prothrombin complex factors were investigated: six had haemophilia B; 14, factor VII defect; four, factor X defect; and three, factor II defect. Nineteen patients (70.3%) had previously received plasma and/or clotting factors concentrates. Among these, markers of hepatitis B infection (HBV) were present in five cases (26.3%) and hepatitis C (HCV) antibodies were found in seven cases (36.8%). The HIV1 prevalence was similarly high. In fact, five patients (26.3%), previously infused with factor IX or prothrombin complex factors concentrates, developed HIV1 infection. No patient with factor VII deficiency became HIV1 positive, despite the administration of unheated factor VII concentrates and the consequent HBV and HCV contamination. In the HIV1 positive group, three patients showed a false positivity for HIV2 antibodies. Five years after seroconversion, three patients developed AIDS (stage IV) and died, one had persistent generalized lymphadenopathy (stage III), and one with post-hepatitis liver cirrhosis was asymptomatic (stage II) for HIV infection. The significant decrease in total white cells, T4 lymphocytes and platelet counts and increase of beta 2-microglobulin and neopterin levels confirmed the prognostic value of these markers for the progression of HIV1 disease. Only one HIV1 negative transfused patient developed anti-HTLV-I p19 antibodies.

Adult↗