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Biomedical subjects

M Fischbach

Publications and source records attributed to M Fischbach.

At least 19 recordsLinked to original sources
PubMed2006

[Best of functional evaluation and cardiac rehabilitation in 2005].

The latest in cardiac rehabilitation has been impacted by: The East German PET publication which showed fewer ischaemic events and progression of the atheromatous disease in symptomatic and stable coronary patients who carry out regular physical exercise in comparison with patients who underwent angioplasty with stenting. Two meta-analyses updated the data showing the benefits of physical training: a 20% reduction in global mortality in coronary disease and 35% in cardiac failure. Two French studies reporting reassuring data for our daily practice: the serious complications of cardiac rehabilitation are exceptionally rare: the register for 2003 with data from 65 French centres, over 25,000 patients and 743,000 patient/exercise hours. Physical training two weeks after mitral valvuloplasty is not harmful for the valve repair and is beneficial in terms of exercise capacity for the patient. Epidemiological studies showing that women and elderly patients are, unfortunately, often excluded from programmes of cardiac rehabilitation.

Cardiovascular Diseases↗
PubMed2005

Synthesis of enantiopure (5R)-hydroxyhexane-2-one with immobilised whole cells of Lactobacillus kefiri.

Whole-cell reduction of (2,5)-hexanedione to yield highly enantiopure (5R)-hydroxyhexane-2-one (enantiomeric excess >99%) with Lactobacillus kefiri DSM 20587 was investigated. Cell immobilisation with sodium cellulose sulphate was chosen as the most suitable encapsulation matrix, giving an immobilisation yield of 40%. Despite the lowered biocatalytic activity from cell immobilisation, the bioreduction process was vastly improved with the help of reaction engineering techniques (batch to a plug flow reactor set-up). High selectivity (95%) and space-time yield (87 g L(-1) day(-1)) were achieved in the plug flow reactor. The biocatalyst remained active (68% residual activity) after 6 days of operation.

Bioreactors↗
PubMed2005

Prevention and treatment of renal osteodystrophy in children on chronic renal failure: European guidelines.

Childhood renal osteodystrophy (ROD) is the consequence of disturbances of the calcium-regulating hormones vitamin D and parathyroid hormone (PTH) as well as of the somatotroph hormone axis associated with local modulation of bone and growth cartilage function. The resulting growth retardation and the potentially rapid onset of ROD in children are different from ROD in adults. The biochemical changes of ROD as well as its prevention and treatment affect calcium and phosphorus homeostasis and are directly associated with the development of cardiovascular disease in pediatric renal patients. The aims of the clinical and biochemical surveillance of pediatric patients with CRF or on dialysis are prevention of hyperphosphatemia, avoidance of hypercalcemia and keeping the calcium phosphorus product below 5 mmol(2)/l(2). The PTH levels should be within the normal range in chronic renal failure (CRF) and up to 2-3 times the upper limit of normal levels in dialysed children. Prevention of ROD is expected to result in improved growth and less vascular calcification.

Algorithms↗
PubMed2005

Hemodialysis in children: general practical guidelines.

Over the past 20 years children have benefited from major improvements in both technology and clinical management of dialysis. Morbidity during dialysis sessions has decreased with seizures being exceptional and hypotensive episodes rare. Pain and discomfort have been reduced with the use of chronic internal jugular venous catheters and anesthetic creams for fistula puncture. Non-invasive technologies to assess patient target dry weight and access flow can significantly reduce patient morbidity and health care costs. The development of urea kinetic modeling enables calculation of the dialysis dose delivery, Kt/V, and an indirect assessment of the intake. Nutritional assessment and support are of major importance for the growing child. Even if the validity of these "urea only" data is questioned, their analysis provides information useful for follow-up. Newer machines provide more precise control of ultrafiltration by volumetric assessment and continuous blood volume monitoring during dialysis sessions. Buffered bicarbonate solutions are now standard and more biocompatible synthetic membranes and specific small size material dialyzers and tubing have been developed for young infants. More recently, the concept of "ultrapure" dialysate, i.e. free from microbiological contamination and endotoxins, has developed. This will enable the use of hemodiafiltration, especially with the on-line option, which has many theoretical advantages and should be considered in the case of maximum/optimum dialysis need. Although the optimum dialysis dose requirement for children remains uncertain, reports of longer duration and/or daily dialysis show they are more effective for phosphate control than conventional hemodialysis and should be considered at least for some high-risk patients with cardiovascular impairment. In children hemodialysis has to be individualized and viewed as an "integrated therapy" considering their long-term exposure to chronic renal failure treatment. Dialysis is seen only as a temporary measure for children compared with renal transplantation because this enables the best chance of rehabilitation in terms of educational and psychosocial functioning. In long term chronic dialysis, however, the highest standards should be applied to these children to preserve their future "cardiovascular life" which might include more dialysis time and on-line hemodiafiltration with synthetic high flux membranes if we are able to improve on the rather restricted concept of small-solute urea dialysis clearance.

Child↗
PubMed2003

Measurement of hydrostatic intraperitoneal pressure: a useful tool for the improvement of dialysis dose prescription.

The prescription of peritoneal dialysis should be individualized based on parameters of tolerance and adequacy. Determination of the intraperitoneal fill volume is essential for optimal patient care. Fill volume enhancement is a factor of exchange surface area recruitment: the wetted, contact peritoneal dialysis membrane. Nevertheless, fill volume enhancement can also lead to patient discomfort, with the potential risk of too high an intraperitoneal pressure (hernia, gastro-esophageal reflux). The perception of the individual patient is also a subjective parameter of fill volume tolerance assessment. In contrast, measurement of the hydrostatic intraperitoneal pressure (IPP, cmH(2)O) allows an objective approach to fill volume tolerance. From our clinical experience of more than 10 years of IPP measurements in child care, we can give a recommendation for normal values in children: less than 18 cm of water, usually between 5 and 15 cm, correlated to the intraperitoneal fill volume (naturally), but individually taking into account age, gender, "accustomization" and overall body mass index.

Child↗
PubMed2003

Genetic variations of the SLC7A9 gene: allele distribution of 13 polymorphic sites in German cystinuria patients and controls.

Cystinuria is a hereditary disorder of cystine and dibasic amino acid transport across the luminal membrane of renal tubules and intestine, resulting in recurrent nephrolithiasis. While mutations in the SLC3A1 gene cause type I cystinuria, patients with non-type I cystinuria carry mutations in the SLC7A9 gene. Both gene products form the renal amino acid transporter rBAT/b0,+AT affected in cystinuria. In the present study a total of 59 patients with different ethnic background were screened for sequence variations in SLC7A9, out of these 32 were of German origin. For determination of allele frequencies of detected polymorphisms, 58 healthy German controls were investigated. Molecular-genetic analysis was performed using single-strand conformation polymorphism analysis, restriction assays and sequencing. Allele frequencies were analyzed statistically for the detected polymorphisms. In addition to the 6 already known variants we identified 7 new polymorphisms. Statistical analyses showed a significantly different distribution of alleles between German patients and German controls in case of the polymorphisms c. 147C>T (exon 2), c.386C>T (exon 3), IVS3+22T>G, c.584C>T (exon 4), c.610T>C (exon 4), c.692C>T (exon 5), c.852C>A (exon 6) and c.872C>T (exon 6). In summary, our results show that cystinuria is a complex disease which is not only caused by mutations in SLC7A9 and SLC3A1, but also influenced by other modifying factors such as variants in SLC7A9.

Alleles↗
PubMed2002

Impact of age on reference values for serum concentration of cystatin C in children.

Recently, cystatin C (cyst C) was proposed for the assessment of glomerular filtration rate, being more accurate than creatinine determination. Reference intervals for cyst C do not vary with age and sex, like creatinine values. Elevated values of cyst C were reported for pre- and full-term infants. Nevertheless, the age cut-off for stable cyst C values i.e., age independence, remains under discussion. Therefore, we conducted a prospective study in 98 healthy children, 51 being under 18 months of age. Cyst C was determined by the nephelometric method. The infants under the age of 18 months had a higher mean serum cyst C value (0.94 +/- 0.24 mg/l) than the older children (0.65 +/- 0.19 mg/l). There was a negative correlation between age and cyst C in the infant group under the age of 18 months (r(2)=0.631, P<0.01). Our results indicate that mean serum cyst C is higher in infants than older children; the age cut-off appears over the age of 1 year of life, presumably reflecting kidney maturation. Our study does not allow accurate assessment of the age cut-off at 18 months or 36 months.

Aging↗
PubMed2002

Severe hypophosphatasia due to mutations in the tissue-nonspecific alkaline phosphatase (TNSALP) gene.

Hypophosphatasia is a rare autosomal recessive inborn error of metabolism characterized by a defective bone mineralisation and deficiency of serum and tissue liver/bone/kidney alkaline phosphatase activity. We report the characterisation of tissue-nonspecific alkaline phosphatase (TNSALP) gene mutation in a patient affected by infantile hypophosphatasia. This boy was the first child of non affected, non related parents. At 1 month of age he presented with palsy of the left upper limb with hypotonia. Length was - 2SD. The anterior fontanel was large. There was a markedly decreased ossification of all bones. All limbs were shortened. Ultrasonographic examination of the kidneys showed nephrocalcinosis. Level of alkaline phosphatases was decreased in the child as well as in the parents. Bone density was decreased. At 2 years of age development was delayed. Weight was - 3,5 SD and OFC - 3SD. The child had craniosynostosis. Molecular studies showed 2 missense mutations, both in exon 6 of the TNSALP gene.

Alkaline Phosphatase↗
PubMed2001

[Tetralogy of Fallot in monozygotic twins].

UNLABELLED: The causative mechanisms of congenital heart defects remain unclear and little is known about the respective implication of chance, genetics and environment, though recent findings in molecular biology may provide further insight into understanding the pathophysiologic basis of congenital heart diseases. CASE REPORT: We report the exceptional but significant case of monozygotic twins both affected by tetralogy of Fallot, for whom prenatal diagnosis ruled out 22q11 microdeletion. CONCLUSION: We discuss how far this observation is consistent with the latest hypothesis, which emphasizes the leading role of genetic factors. Several genes indeed, either separately or in combination, could be responsible for those defects, even if other influences may still come into play.

Chromosomes, Human, Pair 22↗
PubMed2001

Glutathione S-transferase genotypes in systemic sclerosis and their association with clinical manifestations in early disease.

The glutathione S-transferases (GSTs) are a family of enzymes involved in limiting oxidative damage to tissues. Null alleles for one or more of the GST enzymes, especially GSTM1, reportedly occur more frequently in patients with Sjögren's syndrome and systemic lupus erythematosus who possess certain autoantibodies. Because systemic sclerosis (SSc) is a disease in which oxidative damage has been hypothesized to contribute both to immune dysfunction and tissue damage, we sought to determine if patients from a multi-ethnic cohort of SSc patients with early disease (< or =5 years) were more likely than ethnically-matched normal controls to have null alleles for GSTM1 (M1) and/or GSTT1 (T1), and if the null allele status correlated with any major disease features. The data show that while M1 and T1 null genotypes were not significantly increased in SSc compared to ethnically matched controls, their frequencies (especially T1 nulls) were significantly higher among SSc patients with hypertension and pulmonary involvement. This suggests that GST genotype may be a genetic factor that contributes to clinical disease expression in SSc.

Genotype↗
PubMed2001

Lack of association of a functionally relevant single nucleotide polymorphism of matrix metalloproteinase-1 promoter with systemic sclerosis (scleroderma).

Matrix metalloproteinase 1 (MMP-1) is necessary for degradation of interstitial collagen types I, II, and III, which are the major constituents of the extracellular matrix (ECM). Increased expression of MMP-1 has been correlated with invasiveness of certain malignancies and cartilage degradation in rheumatoid arthritis. Increased transcriptional activity of MMP-1 has been reported with a single nucleotide polymorphism (SNP) of the MMP-1 promoter. Systemic sclerosis (SSc) is characterized by increased accumulation and turnover of collagen and other components of ECM. Previous studies have reported increased expression of MMP-1 transcripts in SSc fibroblasts. Therefore, we sought to determine if SSc patients with early disease (< or =5 years) from a multi-ethnic cohort were more or less likely than ethnically-matched normal controls to have an increased frequency of the high promoter activity MMP-1 genotype and whether MMP-1 promoter genotypes correlated with any of the major clinical manifestations of SSc. The results show that the frequency of the high activity promoter genotype in either the heterozygous or homozygous state did not differ significantly between SSc patients and ethnically-matched controls, or between SSc patients with either diffuse or limited scleroderma. Furthermore, MMP-1 promoter genotypes did not significantly correlate with any of the major clinical manifestations of SSc.

Humans↗
PubMed2001

Systemic sclerosis in 3 US ethnic groups: a comparison of clinical, sociodemographic, serologic, and immunogenetic determinants.

OBJECTIVE: To determine whether ethnic factors influence the presentation, serologic expression and immunogenetics of systemic sclerosis (SSc), patients from 3 ethnic groups were compared for clinical features, SSc-associated autoantibodies, and human leukocyte antigen (HLA) class II alleles. METHODS: Fifty-four Hispanics, 28 African Americans, and 79 whites from Texas with recent-onset (less than 5 years) SSc enrolled in a prospective longitudinal study were assessed for sociodemographic, clinical, immunologic, immunogenetic, behavioral, and psychologic parameters using validated instruments and standard laboratory techniques. Serologic and immunogenetic characteristics from these patients and larger retrospective SSc cohorts of the same ethnic groups also were examined. RESULTS: Hispanics and African Americans in the prospective cohort were more likely to have diffuse skin involvement, skin pigmentary changes, digital ulcers, pulmonary hypertension (African Americans), and an overall lower sociodemographic status than whites, who had more facial telangiectasia and hypothyroidism. In the larger combined prospective and retrospective groups of SSc patients, whites were likely to have more anticentromere antibodies (ACA) and African Americans more anti-U1-ribonucleoprotein (RNP) and anti-U3-RNP (fibrillarin) autoantibodies. HLA-DQB1*0301 was significantly associated with SSc per se in all 3 ethnic groups; HLA-DRB1*11 correlated with the anti-topoisomerase I antibody response, and HLA-DRB1*01, DRB1*04, and DQB1*0501 with ACA. CONCLUSIONS: Important sociodemographic, clinical, and serologic differences exist between whites, African Americans, and Hispanics, despite shared genetic (HLA class II) predisposing factors. The impact of these differences on prognosis remain to be determined.

Adult↗
PubMed2001

Hemodialysis in children: principles and practice.

Hemodialysis has benefited from major progress over the last decade, improvements in technology and in clinical management. The morbidity over the sessions have decreased, seizures being exceptional, hypotensive episodes or headaches rare and pain related to the fistula puncture is effectively prevented by xylocaine ointment. The development of urea kinetic modeling allows the calculation of the dialysis dose Kt/V, and an indirect assessment of the protein intake. Even if the validity of these parameters are questioned their analyse provides an assessment and therefore is a "good thing." The patient also benefited from the technological revolution. The newer machines provide for precise control of ultrafiltration volumetrically assessed, buffered bicarbonate became a standard technique, biocompatible and highly efficient membranes and specific material available for infants have been developed. More recently the concept of ultrapure dialysate, ie, free of microbiological contamination, germs and endotoxins was developed, as was the availability of continuous blood volume monitoring during the session. The hemodiafiltration modality especially with the on line concept, because of all the advantages, should not be limited only to patients at risk.

Catheters, Indwelling↗