Biomedical subjects

J Karitzky

Publications and source records attributed to J Karitzky.

3 recordsLinked to original sources

PubMed1998

[31P-mr spectroscopy of peripheral skeletal musculature under load: demonstration of normal energy metabolites compared with metabolic muscle diseases].

PURPOSE: 31P-MR spectroscopy of skeletal muscle under exercise was used to obtain the range of normal variation and comparison was made for different neuromuscular diseases. METHODS: 41 examinations of 24 volunteers and 41 investigations in 35 patients were performed on 1.5 T MR systems (Gyroscan 515 und S15/ACSII, Philips). Localised 31P-MR spectra of the calf muscle were obtained in time series with a resolution of 12 s. RESULTS: Two types of muscle energy metabolism were identified from the pattern of spectroscopic time course in volunteers: While the first group was characterised by a remarkable decline to lower pH values during exercise, the second group showed only small pH shifts (minimum pH: 6.48 +/- 0.13 vs 6.87 +/- 0.07, p < 10(-6)) although comparable workload conditions were maintained. The pH-values correlated well with blood lactate analysis. Patients with metabolic disorders and chronic fatigue syndrome (CFS) showed decreased resting values of PCr/(PCr + Pi) and increased pH levels during exercise. PCr recovery was significantly delayed (0.31 vs 0.65 min-1, p < 0.00005) in metabolic muscle disorders but was normal in CFS patients. CONCLUSION: Findings in volunteers indicate utilisation of different metabolic pathways which seems to be related to the fibre type composition of muscle. Reduced resting levels for PCr/(PCr + Pi), altered pH time courses, and decreased PCr recovery seem to be helpful indicators for diagnosis of metabolic muscle disorders.

Carbohydrate Metabolism, Inborn Errors↗

PubMed1996

Muscle phosphofructokinase deficiency in two generations.

Phosphofructokinase (PFK) is the key regulatory enzyme of glycolysis. Patients lacking the muscular isoform of PFK typically present with myopathy and compensated hemolysis (glycogenosis type VII or Tarui's disease). Since 1965 about 30 cases of muscular PFK deficiency have been reported. In most cases family history suggests a recessive inherited trait. We describe a family of Ashkenazi Jewish origin with two members in subsequent generations suffering from muscular PFK deficiency. The propositus, a 19-year-old male patient presented with weakness, myalgias and exercise intolerance since early infancy. His father also had early fatigue on exercise with myalgias; the mother and a 12-year-old brother were asymptomatic. Muscle biopsy of both the propositus and his father showed increased glycogen storage and absent histochemical stain for PFK. Biochemical studies of muscle revealed a markedly decreased PFK activity and DNA analysis of the muscle PFK gene revealed compound heterozygosity in both cases. This is the first description of proven muscle PFK deficiency (glycogenosis type VII) in two subsequent generations.

Adult↗

PubMed1996

ALS.

The cause of ALS is not known but there are four main hypotheses about its etiology. First, an excess of extracellular glutamate in the CNS of patients with ALS resulting from a defect in glutamate reuptake may have excitotoxic effects on motor neurons. Clinical trials suggest the antiglutamate agent riluzole improves survival of patients with the disease. Second, ALS may be an autoimmune disease, but immunologically-based treatments have been unsuccessful. The third hypothesis is that ALS results from a lack of neurotrophic growth factors. Preliminary results from clinical trials indicate recombinant human insulin-like growth factor I offers therapeutic promise. Finally, familial ALS is sometimes linked to a gene encoding a Cu/Zn-binding superoxide dismutase; the mutations in ALS are thought to result in gain of function of dismutase activity. The involvement of superoxide dismutase in sporadic ALS is unclear.

Amyotrophic Lateral Sclerosis↗