Modification of the environment is not the most efficient way to prevent type 1 diabetes.
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Biomedical subjects
Publications and source records attributed to M Redondo.
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Myotonic muscular dystrophy (MMD) is a genetic disease caused by a defective enzyme, myotoninkinase. Male patients with MMD are reported to have reduced fertility. The purpose of this work was to study sperm capacitation and acrosome reaction in the ejaculates of sterile males with MMD and of healthy males (control group). The expression of the specific D-mannose receptors was explored by microscopic examination and by flow cytometry analysis. In addition, the binding patterns of Pisum sativum (PSA) lectin to acrosome content and outer acrosomal membrane in the spermatozoa of each group were analysed. Both the capacitation and the acrosome reaction in the spermatozoa of the MMD group were deficient and these findings strongly suggest that these anomalies may account for the sterility of these patients.
The in vitro activities of the new agents linezolid, quinupristin-dalfopristin, moxifloxacin, and trovafloxacin were determined and compared with those of penicillin, clindamycin, and four macrolides against 53 erythromycin-resistant Streptococcus pneumoniae, 117 S. pyogenes (64 erythromycin-susceptible and 53 -resistant), and 101 S. agalactiae (53 erythromycin-susceptible and 48 -resistant) isolates. Differentiation of macrolide resistance phenotypes was performed by the double-disk method. The genetic basis for macrolide resistance in 52 strains was also determined. The M phenotype was found in 84.9, 6.3, and 1.9% of S. pyogenes, S. agalactiae, and S. pneumoniae isolates, respectively. These strains were susceptible to miocamycin and clindamycin. Strains with the inducible phenotype accounted for 27.1% of S. agalactiae isolates and 9.4% each of S. pyogenes and S. pneumoniae isolates. All erythromycin-resistant isolates were also resistant to the 14- and 15-membered macrolides tested. Strains with all three phenotypes were susceptible to </=2 microgram of linezolid per ml. Quinupristin-dalfopristin exhibited good in vitro activity against all strains, irrespective of their resistance to erythromycin (MICs at which 90% of the isolates tested were inhibited [MIC(90)s], 0.2 to 1 microgram/ml). Against the erythromycin-resistant S. pyogenes and S. agalactiae strains, moxifloxacin and trovafloxacin were the most active agents (MIC(90)s, 0.1 microgram/ml). The new antimicrobials evaluated may be alternative agents to treat infections caused by macrolide-resistant as well as macrolide-susceptible streptococci.
We investigated how the optical aberrations associated with the anterior surface of the human cornea change with age in a normal population. Aberrations were computed for a central part of the cornea (4, 5, and 6 mm in diameter) from the elevation data provided by a videokeratographic system. Measurements were obtained in 59 normal healthy, near-emmetropic [spherical equivalent lower than 2 diopters (D)] subjects of three age ranges: younger (20-30 years old), middle-aged (40-50 years old), and older (60-70 years old). The average corneal radius decreased with age and the cornea became more spherical. As a consequence, spherical aberration was significantly larger in the middle-aged and older corneas. Coma and other higher-order aberrations also were correlated with age. The root mean square of the wave aberration exhibited a linear positive correlation (P < 0.003) with age for the three ranges of pupil diameter. Despite a large intersubject variability, the average amount of aberration in the human cornea tends to increase moderately with age. However, this increase alone is not enough to explain the substantial reduction previously found in retinal image quality with age. The change in the aberrations of the lens with age and the possible loss of part of the balance between corneal and lenticular aberrations in youth may be the main factors responsible for the reduction of retinal image quality through the life span.
C1-esterase inhibitor (C1-Inh) therapy was introduced in clinical medicine about 25 years ago as a replacement therapy for patients with hereditary angioedema caused by a deficiency of C1-Inh. There is now accumulating evidence, obtained from studies in animals and observations in patients, that administration of C1-Inh may have a beneficial effect as well in other clinical conditions such as sepsis, cytokine-induced vascular leak syndrome, acute myocardial infarction, or other diseases. Activation of the complement system, the contact activation system, and the coagulation system has been observed in these diseases. A typical feature of the contact and complement system is that on activation they give rise to vasoactive peptides such as bradykinin or the anaphylatoxins, which in part explains the proinflammatory effects of either system. C1-Inh, belonging to the superfamily of serine proteinase inhibitors (serpins), is a major inhibitor of the classical complement pathway, the contact activation system, and the intrinsic pathway of coagulation, respectively. It is, therefore, endowed with anti-inflammatory properties. However, inactivation of C1-Inh occurs locally in inflamed tissues by proteolytic enzymes (e.g., elastase) released from activated neutrophils or bacteria thereby leading to increased local activation of the various host defense systems. Here we will give an overview on the biochemistry and biology of C1-Inh. We will discuss studies addressing therapeutic administration of C1-Inh in experimental and clinical conditions. Finally, we will provide an explanation for the therapeutic benefit of C1-Inh in so many different diseases.
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During sepsis the complement system, the contact activation system and the coagulation cascade are activated. Activation of these plasmatic cascades contributes to the development of multiple organ failure and the high mortality rate of severe sepsis and septic shock. C1-inhibitor is the main inhibitor of the classical pathway of the complement system (C1s and C1r), of the contact activation system (factor XIIa and kallikrein) and of the intrinsic pathway of coagulation (factor XIa). During sepsis, C1-inhibitor is proteolytically inactivated. The increase of inactivated C1-inhibitor in plasma correlates positively with mortality in septic patients. C1-inhibitor substitution has been shown to reduce the mortality in experimental animals with severe sepsis or septic shock. Only a few cases of C1-inhibitor substitution in patients with severe sepsis or septic shock have been reported. C1-inhibitor has been shown to attenuate the activation of the complement system and the contact activation system and to improve hypotension. Based on this convincing pathophysiological concept and the results of the animal studies, we initiated the "Bernese C1-inhibitor study", a randomised double-blind and placebo-controlled pilot study involving administration of C1-inhibitor to patients with severe sepsis or septic shock. If the results of this pilot study confirm the results of the reports mentioned above, they will serve as a base for larger multicentre studies.
BACKGROUND: The platelet membrane glycoprotein Ia/IIa plays a major part in platelet function as a primary receptor for collagen. A previous report showed a variation of glycoprotein Ia/IIa receptor density and function associated with two silent and linked polymorphisms (807C/T and 873G/A) within the glycoprotein Ia gene. Because platelet thrombus formation is implicated in the pathogenesis of acute myocardial infarction, we investigated these polymorphisms among patients who had had a myocardial infarction. METHODS: We did a 2/1 case-control study including 177 patients (median age 57.0 [range 32-72] years) and 89 controls with same age and sex. Distributions of the 807C/T and 873G/A polymorphisms were investigated by genotyping DNA by PCR, single-strand conformation polymorphism analysis, and sequencing. FINDINGS: The prevalence of the homozygous 807T/873A genotype was 2.9 times higher among patients with myocardial infarction than among controls (16.4% vs 5.6%, p=0.022). There was an association between patients homozygous for the 807T/873A allele and myocardial infarction (odds ratio 3.3 [95% CI 1.2-8.8]), which was strongest in a subgroup of smokers. The homozygous 807T/873A genotype remained an independent risk factor for myocardial infarction (p=0.005) when age, sex, smoking, hypertension, diabetes, body-mass index, LDL-cholesterol and HDL-cholesterol, and fibrinogen were adjusted for by logistic regression. INTERPRETATION: The 807T/873A homozygosity of the platelet glycoprotein Ia/IIa gene polymorphism, associated with differences in surface collagen receptor density and activity, appears to be an independent risk factor for acute myocardial infarction. Our findings need to be confirmed in a larger, prospective study that includes patients from different populations and cardiovascular risk groups.
Recent developments in cattle tick control have incorporated the use of recombinant Bm86 vaccines against this ectoparasite. The vaccine developed by our group (Gavac) contains an antigen expressed in Pichia pastoris, and has been successfully employed for the control of tick infestations and transmission of tick-borne diseases. Here, we examined the safety and effect of the Gavac vaccine on reproductive parameters in cattle. Toxicity tests in mice and guinea pigs demonstrated the safety of Gavac. To study the adverse effects of vaccination on reproduction, a field trial involving 9,500 animals in Cuba was conducted. The cattle at 3 farms were vaccinated while those on a fourth farm were left unvaccinated and served as the control. Following vaccination, the control of tick infestation and the transmission of babesiosis were used to demonstrate the efficacy of the vaccine. No adverse effects were observed in any of the reproductive parameters studied when comparing the data before and after vaccination with Gavac and between the vaccinated farms and the control farm. These results demonstrate that under the conditions of our study vaccination with Gavac is safe for use on cattle.
The control of tick infestations and the transmission of tick-borne diseases remain a challenge for the cattle industry in tropical and subtropical areas of the world. Traditional control methods have been only partially successful and the parasites continue to result in significant losses for the cattle industry. Recently, vaccines containing the recombinant B. microplus gut antigen Bm86 have been developed. Our vaccine formulation (Gavac, Heber Biotec S.A., Havana, Cuba) has been registered and is commercially available in Cuba, Colombia, Dominican Republic, Brazil and Mexico. In controlled pen trials, Gavac has been effective for the control of artificial infestations of B. annulatus, B. decoloratus and chemical-sensitive and resistant B. microplus strains from Australia, Africa, America and Iran. In controlled field trials in Cuba, Brazil, Argentina and Mexico, Gavac has shown a 55-100% efficacy in the control of B. microplus infestations in grazing cattle 12-36 weeks after the first vaccination. Field trials under production conditions have been conducted in Cuba, Colombia, Brazil and Mexico in pure and cross-bred cattle herds. The application of Gavac has increased the time between acaricide treatments by an average of 32 /-21 days (P = 0.0005) resulting in important savings for the cattle industry. In Cuba, a cost-effectiveness analysis was conducted in more than 260000 animals. The cost-effectiveness analysis showed a 60% reduction in the number of acaricide treatments, together with the control of tick infestations and transmission of babesiosis, which resulted in savings of 23.4 dollars animal(-1) year (-1). These results clearly demonstrate the advantage of vaccination and support the application of Gavac for the control of Boophilus spp. infestations.
Throughout most of the twentieth century, tick infestations on cattle have been controlled with chemical acaricides, typically administered by dipping or spraying. This approach can cause environmental and residue problems and has created a high incidence of acaricide resistance within tick populations in the field. Recently we developed a vaccine against Boophilus microplus employing a recombinant Bm86 antigen preparation (Gavac), (Heber Biotec S.A., Havana, Cuba) which has been shown to induce a protective response in vaccinated animals. Here we show for the first time under field conditions a near 100% control of B. microplus populations resistant to pyrethroids and organophosphates, by an integrated system employing vaccination with Gavac and amidine treatments. This method effectively controls tick infestations while reducing the number of chemical acaricide treatments and consequently the rise of B. microplus populations resistant to chemical acaricides.
We describe a 56-year-old patient with multiple myeloma and very high paraprotein concentration (IgG kappa). Coagulation studies showed unclottable thrombin and reptilase times caused by impaired fibrin polymerization presumably due to the paraproteinemia. There was no obvious bleeding tendency. The differential diagnosis of thrombin time prolongation includes inhibition of the added thrombin by exogenous heparin, hirudin or seldom by endogenous heparin-like anticoagulants or by acquired (bovine) thrombin antibodies, qualitative fibrinogen disorders (congenital and acquired dysfibrinogenemia), quantitative fibrinogen disorders (severe hypo- and afibrinogenemia) and delayed fibrin polymerization due to fibrin/fibrinogen degradation products, paraproteins and antibodies against fibrin(ogen). In multiple myeloma, thrombin time prolongation may seldom be due to endogenous heparin-like anticoagulants or antibodies to thrombin and more frequently to impaired fibrin polymerization by paraproteins. Simultaneous reptilase time prolongation as present in this case hints to this latter possibility.
A 47-year-old patient with several episodes of bleeding after tonsillectomy, after an excision of a sacral dermoid and after urinary tract surgery presented with a mechanical ileus and was admitted to the department of visceral surgery. Preoperative analysis revealed a prolonged activated partial thromboplastin time (aPTT) of 93 seconds (normal range: 40-60 seconds), whereas the prothrombin time and thrombin time were normal. A mixture of 1 volume patient plasma and 1 volume normal plasma gave a normal aPTT, both before and after incubation of the plasma mixture at 37 degrees C for 1 hour. The patient's history and the prolonged aPTT as the only abnormal clotting test indicated deficiency of either factor VIII, factor IX, factor XI or von Willebrand factor with consecutively diminished factor VIII. Laboratory analysis revealed a factor XI of 4% indicating severe factor XI deficiency. Laparotomy was successfully performed without any hemorrhagic complications under fresh frozen plasma substitution.
By virtue of a severely prolonged aPTT with a normal thromboplastin time (prothrombin time) and a normal thrombin time, severe FXII deficiency has been diagnosed in a woman without a bleeding diathesis or a history of thromboembolic complications. A deficiency of a factor of the contact activation system (FXII, prekallikrein, high molecular weight kininogen) is usually diagnosed during routine coagulation tests demonstrating a prolonged aPTT. The severe and partial deficiency of FXII, of prekallikrein or high molecular weight kininogen is not associated with a bleeding tendency. In contrast, severely factor XI deficient subjects may suffer from a mild hemorrhagic diathesis, whereas FVIII deficiency (hemophilia A, autoimmune "hemophilia", von Willebrand disease) and FIX deficiency (hemophilia B) are associated with a bleeding tendency of varying severity, depending on the clotting activity of FVIII or FIX, respectively. An isolated prolongation of the aPTT due to a lupus anticoagulant, however, is frequently associated with arterial and/or venous thrombosis. Therefore, in case of a prolongation of the aPTT, its cause has to be determined.
Increased levels of hemostatic factors and genetic mutations of proteins involved in coagulation may play a role in the pathogenesis of coronary artery disease. We investigated clotting activity of factors II (FII:C), V (FV:C), VII (FVII:C), and X (FX:C), the prothrombin gene 20210G-->A transition, and the factor V Leiden mutation in 200 survivors of myocardial infarction and in 100 healthy controls. FV:C (P<0.0001) and FVII:C (P<0.0001) were found to be independent risk factors for myocardial infarction. High FV:C or high FVII:C combined with smoking or arterial hypertension increased the relative risk for myocardial infarction up to 50-fold. One of 177 patients (0.6%) and 4 of 89 controls (4.5%) had the prothrombin 20210 AG genotype. Eleven of 177 patients (6.2%) and 6 of 89 controls (6.7%) were heterozygous for the factor V Leiden mutation. No homozygous carrier for these mutations was found. Neither the prothrombin gene 20210G-->A transition (odds ratio [OR], 0.1; 95% confidence interval [CI], 0.01 to 1.1) nor the factor V Leiden mutation (OR, 1.0; 95% CI, 0.4 to 2.8) were associated with an increased relative risk for myocardial infarction. In conclusion, our data indicate that neither the prothrombin gene 20210G-->A transition nor the factor V Leiden mutation are risk factors for myocardial infarction. High FVII:C was confirmed to be an independent risk factor for myocardial infarction. Moreover, we describe for the first time that high FV:C is an independent risk factor for myocardial infarction.
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To further elucidate the debated role of hereditary FXII deficiency as a thrombophilic risk factor this follow-up study on 65 subjects out of 12 Swiss families was undertaken (follow-up: 6 yrs). Fifteen severely FXII deficient subjects (FXII:C < 1%), 35 partially FXII deficient subjects (FXII:C > or = 1-59%), 10 with normal FXII values (FXII:C > or = 70%), and 5 non-classifiable subjects (FXII:C > or = 60-69%) were reevaluated. Eight subjects (4 severely and 3 partially FXII deficient, 1 non-classifiable) were newly enrolled. Four instances of deep vein thrombosis, one superficial vein thrombosis and one myocardial infarction were noted in 2 out of 19 severely FXII deficient subjects during a total life-time period of 866.6 patient-years. In 38 partially FXII deficient subjects (1862.8 patient-years) one ischemic cerebrovascular stroke and one superficial vein thrombosis were recorded in 2 individuals. The 10 subjects with normal FXII values (498.2 patient-years) remained thrombosis-free. One superficial vein thrombosis occurred in an unclassifiable woman. None of the 3 different FXII gene defects revealed in our patients was specifically associated with thromboembolic complications. Kaplan-Meier analysis of thrombosis-free survival suggests that hereditary partial (and probably severe) FXII deficiency does not constitute a thrombophilic condition.
PURPOSE: To determine the average optical performance of the human eye, in terms of the modulation transfer function (MTF), as a function of age. METHODS: An apparatus was constructed to measure the ocular MTF, based on the recording of images of a green, 543-nm laser-point source after reflection in the retina and double pass through the ocular media. MTFs were computed from the average of three 4-second-exposure double-pass images recorded by a slow-scan, cooled charge-coupled device camera. The ocular MTF was measured for three artificial pupil diameters (3 mm, 4 mm, and 6 mm) with paralyzed accommodation under the best refractive correction in 20 subjects for each of three age categories: young subjects aged 20 to 30 years, middle-aged subjects aged 40 to 50 years, and older subjects aged 60 to 70 years. The selected subjects passed an ophthalmologic examination, excluding subjects with any form of ocular or retinal disease, spherical or cylindrical refractive errors exceeding 2 D, and corrected visual acuity lower than 1 (0.8 in the older age group). RESULTS: The average MTF was determined for each age group and pupil diameter. A two-parameter analytical expression was proposed to represent the average MTF in each age group for every pupil diameter. The ocular MTFs declined as age increased from young to older groups. The SD of the MTF results within age groups was lower than the differences between the mean for each group. CONCLUSIONS: The average optical performance of the human eye progressively declines with age. These MTF results can serve as a reference for determining mean ocular optics according to age.