Potential modifier role of the R618Q variant of proalpha2(I)collagen in type I collagen fibrillogenesis: in vitro assembly analysis

An arginine to glutamine substitution in the triple helix of proalpha2(I)collagen (R618Q) was first reported in a patient with a variant of Marfan syndrome and later identified in conjunction with a second mutation in a patient with osteogenesis imperfecta (OI). The presence of the R618Q proalpha2(I)collagen allele in unaffected or mildly affected family members suggests that the R618Q allele is either a non-affecting polymorphism or a potential genetic modifier. Conservation of arginine618 across species and fibrillar collagen types suggests it is functionally significant. To investigate the functional significance of the R618Q proalpha2(I)collagen allele, we isolated type I collagen from cultured dermal fibroblasts of control and two unrelated individuals heterozygous for the R618Q proalpha2(I)collagen allele and evaluated helical stability and fibrillar assembly. Type I collagen thermal stability analyzed by protease susceptibility and CD spectroscopy demonstrated no statistical difference between control and R618Q containing collagen molecules. In vitro fibril assembly analyses demonstrated that R618Q containing collagen exhibits rapid fibrillar growth with minimal fibril nucleation phase. Further, electron microscopy demonstrated that the diameter of assembled R618Q containing collagen fibrils was approximately 20% of control collagen fibrils. These findings suggest the R618Q variant does not impact triple helical stability but has a role in collagen fibril assembly, supporting the hypothesis that the R618Q proalpha2(I)collagen variant is a modifier of connective tissue structure/function and is potentially involved in disease pathogenesis.     

An optimized PCR leads to rapid and highly sensitive detection of Borrelia burgdorferi in patients with Lyme borreliosis.

The present study aimed at developing an optimized PCR protocol fro the sensitive and specific detection of all three Borrelia burgdorferi genospecies pathogenic to humans in Lyme borreliosis patients. A rapid DNA extraction method using alkaline lysis was introduced and was found to be superior to other DNA extraction methods. Nested PCR was performed with primer sets targeting the plasmid-located ospA gene and a chromosomal gene segment encoding a 66-kDa protein (p66). In spiked synovial fluid (SF) fewer than three borreliae/sample were detected. The specificities of the amplicons were confirmed by Southern blot analysis with PCR-derived probes. Urine, cerebrospinal fluid (CSF), and SF specimens from 57 patients with Lyme borreliosis and from 58 controls were examined. In clinical samples the diagnostic sensitivity of PCR was 85% with SF samples, 79% with urine samples, and 91% with paired SF-urine samples from patients with Lyme arthritis and was 79% with CSF samples, 45% with urine samples, and 87% with paired CSF-urine specimens from neuroborreliosis patients. One patient each with neuroborreliosis and with Lyme arthritis had PCR-positive urine samples only. In 17% of all cases both primer sets yielded positive results, while the other patients were positive with only one primer set. Among these, more positive results were obtained with the p66 gene primer than with the ospA primer. The specificity exceeded 99%. We conclude that DNA from B. burgdorferi sensu lato species can sensitively and specifically be detected with the optimized PCR method described. At least two different primer sets should be used, and whenever possible, urine and CSF or SF should be analyzed in parallel to achieve maximum sensitivity of the test. This protocol, therefore, considerably enhances the diagnostic power of PCR in patients with B. burgdorferi infection.     

Gleichstrommessungen an der menschlichen Haut bei Quellung und Entquellung des Gewebes

Zusammenfassung 1. Die biophysikalischen Ursachen meßbarer Veränderungen im Verhalten des menschlichen Hautwiderstandes werden mit der Methode des Elektropermeagramms durch Aufzeichnung eines gewebsaufladenden Gleichstroms untersucht.2. Durch verschiedenartige und variierte experimentelle Versuchsanordnungen sowie klinische Beobachtungen wird nachgewiesen, daß den Schweißdrüsen weder in morphologischer noch funktioneller Beziehung ein erkennbarer Einfluß auf das Verhalten des polarisatorischen Hautwiderstandes, des Anfangs- und Endwiderstandes im Elektropermeagramm zuzuschreiben ist.3. Für Veränderungen der Hautwiderstände ist der Hydratationszustand der lebenden Epidermis im Sinne ihrer Quellung und Entquellung maßgebend.     

Fetal development in experimental uremia

Summary Uremic women on hemodialysis with metabolic bone disease (hyperparathyroidism, osteomalacia resulting from defective vitamin D metabolism) and anemia (erythropoietin deficiency) are known to give birth to infants without bone disease or anemia. Therefore, skeletal development (enchondral and desmal bone formation) and hepatic erythropoiesis were evaluated in fetuses of uremic rats. These fetuses failed to show defective mineralisation or evidence of bone disease. Bolus injection of high doses of exogenous PTH into the maternal or fetal organism did not affect fetal bone histology. In addition, no apparent defect of bone mineralisation or bone formation was found in fetuses of ricketic rats. Normal mineralisation in the offspring of uremic rats may be explained by fetal hyperphosphatemia and/or insensitivity of fetal (woven) bone mineralisation to vitamin D.Absence of fetal anemia (normal hematocrits, normal density of hematopoietic cells in the liver) in the presence of maternal anemia is presumably due to the insensitivity of fetal erythropoiesis to erythropoietin.With the support of Deutsche Forschungsgemeinschaft     

Trisomy 4 as the sole cytogenetic abnormality in a Waldenström macroglobulinemia

We report a case of Waldenstr?m macroglobulinemia with trisomy 4 as the sole cytogenetic abnormality. Trisomy 4 has been reported previously in Waldenstr?m macroglobulinemia, but only in conjunction with multiple chromosomal aberrations. Trisomy 4 has been reported in other hematologic malignancies including acute myeloid and lymphoid leukemias.     

Über den tatsächlichen Orthophosphat- und N-Phosphorylkreatingehalt des Säugetierherzens

Summary 1. Cardiac ventricular muscle of adult, anesthetized, open-chest dogs, guinea pigs, and rabbits given artificial respiration was compressed by means of a pair of –190°C cold aluminum tongs in situ in 0.02–0.4 seconds to frozen plates 0.4–1.5 mm in thickness.2. Determinations of phosphates extracted from the finely powdered plates with 0° or –35°C cold perchloric acid yielded, among other results, the following values per gram of dog, guinea pig, and rabbit myocardium, respectively: 1.9, 2.0, and 1.9 moles of orthophosphate; and 12.8, 10.9, and 8.2 moles of N-phosphorylcreatine (labile phosphate). Bound creatine, analyzed in extracts of guinea pig and rabbit hearts, corresponded quantitatively to the labile phosphate.3. Cardiac muscle samples which were excised and immediately immersed in liquid air contained 3–4 times as much orthophosphate and only a little more than half as much phosphorylcreatine as the metal-cooled tissue. There was also less total acid-soluble phosphate present. The sum of orthophosphate and phosphorylcreatine and the amounts of 10-minute-phosphate and of total creatine were not significantly altered by excision and freezing in liquid air.4. The rapidly beating hearts contained per gram (a) less orthophosphate than is found in the resting skeletal musculature; and (b) as much as or more phosphorylcreatine than there exists, according to data in the literature, in certain types of skeletal muscle in the resting state.5. The problem of obtaining a warm-blooded heart, or a part of it, for analysis without inducing changes in chemical composition is considered in relation to the anatomy of the organ. The advantage is noted which the cooling tongs technique affords in this regard over other methods of tissue freezing.

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Vorläufige Mitteilung: Wollenberger, Krause u. Wahler (1958).