Mikrokallusformationen der Spongiosa Ein bisher unterschätzter reparativer Mechanismus des Skelettsystems

Zusammenfassung Mikrokallusformationen lassen sich in nahezu allen Skelettabschnitten der Spongiosa nachweisen. Mikrokallus besteht aus Geflechtknochen, der sich an lokal überbelasteten Stellen in der Spongiosa bildet. Mit Hilfe einer speziellen Pr?parationstechnik wurden 26 skelettgesunde und 11 Wirbels?ulen von F?llen mit Osteoporose untersucht. Mikrokallusformationen finden sich bevorzugt bei Frauen ?lter als 45 Jahre in den unteren Wirbels?ulenabschnitten. Dabei hat die Mikroarchitektur der Spongiosa (TBPf) einen st?rkeren Einflu? auf die Anzahl der Mikrokalli, als individuelle Trabekelparameter (Tb.N, BV/TV und Tb.Th). Nur in 33 % der Formationen lassen sich Frakturspalten nachweisen. Mikrokallusformationen k?nnen nichtinvasive Knochenmassemessungen verf?lschen. Auch wenn Mikrokallusformationen Indikatoren für eine Instabilit?t der Spongiosa sind, tragen sie zur Knochenregeneration bei, und die Entstehung neuer Trabekel ist durch sie m?glich. Die Vorstellung, da? Osteoporose das Resultat einer verminderten Mikrokallusbildung ist, trifft nicht zu.      

The spectrum of aldolase B (ALDOB) mutations and the prevalence of hereditary fructose intolerance in Central Europe

We investigated the molecular basis of hereditary fructose intolerance (HFI) in 80 patients from 72 families by means of a PCR-based mutation screening strategy, consisting of heteroduplex analysis, restriction enzyme digest, DNA single strand electrophoresis, and direct sequencing. For a subset of patients mutation screening with DHPLC was established which turned out to be as fast and as sensitive as the more conventional methods. Fifteen different mutations of the aldolase B (ALDOB) gene were identified in HFI patients. As in smaller previous studies, p.A150P (65%), p.A175D (11%) and p.N335K (8%) were the most common mutated alleles, followed by c.360_363delCAAA, p.R60X, p.Y204X, and c.865delC. Eight novel mutations were identified in eight families with HFI: a small indel mutation (c.1044_1049delTTCTGGinsACACT), two small deletions (c.345_372del28; c.841_842delAC), two splice site mutations (c.113-1G>A, c.799+2T>A), one nonsense mutation (c.612T>G (p.Y204X)), and two missense mutations (c.532T>C (p.C178R), c.851T>C (p.L284P)). By mutation screening for the three most common ALDOB mutations by DHPLC in 2,000 randomly selected newborns we detected 21 heterozygotes. Based on these data and after correction for less common and private ALDOB mutations, HFI prevalence in central Europe is estimated to be 1:26,100 (95% confidence interval 1: 12,600-79,000).     

Telecommunication and telepathology. New diagnostic routes for orthopaedics and orthopaedic pathology

In a pilot project of the Department of Bone Pathology of the University of Hamburg and the Orthopaedic Department of the University of Heidelberg, the cases of 121 patients with suspicion of a primary bone tumour have been discussed at weekly interdisciplinary conferences during the period from July 2001 to May 2002., The consequent differential diagnoses were made prior to the biopsy, the optimal location of the biopsy and the further strategy was determined according to the guidelines of the international bone tumour centres. The latter includes the decision if a conventional biopsy or a intraoperative pathology examination on frozen sections should be performed. In 27 cases an intraoperative pathology examination was performed and then assessed in Hamburg. In 24 cases this diagnosis was identical with the final diagnosis. In three cases no definitive diagnosis could be made from the frozen sections. Additionally the pathohistological diagnoses of the cases of the previous week have been discussed in the video-conferences. Through this a unusually close interdisciplinary cooperation over a large distance has evolved, that is highly appreciated especially by the young and less experienced colleagues at the department of bone pathology and the orthopaedic department in Heidelberg. The awareness of the potential and limitations of a medical subject leads to an improved safety in the diagnostic process for bone tumours. The interdisciplinary discussion of all aspects of the diseases may also optimise the therapy of bone tumours.     

Measurement of MPO activity as model for detection of granulocyte infiltration in different tissues

Activity of myeloperoxidase (MPO) was determined in different tissues to detect granulocyte infiltration. MPO was measured in the mouse ear after injection of interleukin-1, in the rat paw after carrageenan-induced edema and in the lung of sensitized guinea pigs after ovalbumin inhalation. Pretreatment of the animals with antiinflammatory drugs abolished the increase of MPO activity in tissues induced by this different stimuli.     

Oxidative stress and sleep apnoea in clinically healthy infants in the first year of life

Summary Question of the study   Respiratory instability as well as tissue damage by free radicals (oxidative stress) have been hypothesized to play a role in cases of sudden and unexpected infant death in the first year of life. The ratio of the oxidized/reduced form of redox compounds in the circulation could be used as a marker of oxidative stress. Therefore, the sleep apnoea rate and redox status of coenzyme Q10 (CoQ10) (percentage of the oxidized form in total CoQ10) were measured in a population of clinically healthy infants in their first year of life in order to study whether a physiological parameter of respiratory instability is related to a biochemical parameter of oxidative stress. Patients and methods   Between May and December 1999, 323 infants in the first year of life were referred to a paediatric sleep laboratory. Sleep apnoea rate, periodic breathing and parameters of oxygenation (SaO₂ and TcPO₂) were calculated based on polysomnographic recordings. The CoQ10 redox status was calculated based on high-pressure liquid chromatographic (HPLC) analysis. Results   Statistical analysis showed an age-dependent decrease in apnoea rate ( r = – 0.38) and CoQ10 redox status ( r = – 0.40). An increased CoQ10 redox status (median: 16.6 %; range: 7.3 – 29.7 %) was found in infants with high apnoea rates above the 90^th percentile of a reference group in comparison with infants with apnoea rates below the 90^th percentile of a reference group (median: 10.4 %; range: 5.1 – 20.4 %; P = 0.031). Conclusions   These findings may indicate that high apnoea rates are accompanied by increased formation of free radicals in clinically healthy infants in the first year of life.     

Cytokine interactions in experimental cutaneous leishmaniasis. II. Endogenous tumor necrosis factor-alpha production by macrophages is induced by the synergistic action of interferon (IFN)-gamma and interleukin (IL) 4 and accounts for the antiparasitic effect mediated by IFN-gamma and IL 4

Tumor necrosis factor-alpha (TNF-alpha) strongly activates murine peritoneal macrophages (M phi) for killing of amastigotes from Leishmania major in the presence of low amounts of interferon-gamma (IFN-gamma). Recently, we found that IFN-gamma and interleukin 4 (IL 4) also synergistically enhance the antileishmanial potential of M phi. In this report, evidence is provided that the synergism of IFN-gamma and IL 4 is based on the ability of the lymphokines to induce the endogenous production of TNF-alpha. First, both IFN-gamma and IL 4 as single agents and in combination were potent inducers of TNF-alpha production by M phi infected with L. major amastigotes. Second, the synergistic effect of IFN-gamma and IL 4 on parasite killing by M phi strongly correlated with their synergistic effect on the release of TNF-alpha. Third, the IFN-gamma/IL 4-mediated parasite elimination was completely abrogated not only in the presence of antibodies to IFN-gamma and IL 4, but also with an antibody specific for TNF-alpha. Consistent with the conclusion that endogenously produced TNF-alpha accounts for the synergism of IL 4 with IFN-gamma is the finding that N omega-monomethyl-L-arginine, an inhibitor of the L-arginine-dependent generation of microbicidal nitrogen intermediates, totally blocked the M phi activation induced by IFN-gamma combined with IL 4 as well as by IFN-gamma combined with TNF-alpha. These results underline the complex interplay of cytokines derived from lymphocytes and M phi and the role of TNF-alpha as pivotal factor for the induction of antileishmanial effector functions.     

5′-Cytosine DNA-methyltransferase mRNA levels in hereditary colon carcinoma

 DNA methylation plays an important part in the regulation of gene expression. Alterations in DNA methylation in tumours have been reported and have been used to generate hypotheses about mutagenesis and silencing of tumour suppressor genes. However, the underlying mechanism is still poorly understood, and conflicting data on the levels of overexpression of 5′-cytosine DNA methyltransferase in sporadic colon carcinoma have been published. We used a competitive RT-PCR assay for quantification of mRNA of 5′-cytosine DNA methyltransferase in colon biopsies obtained from patients with hereditary colon carcinoma syndromes and compared the results with those obtained in a control group. No significant difference was found between the flat mucosa of FAP patients and the mucosa of the control group. In FAP and HNPCC patients, the 5′-cytosine DNA methyltransferase mRNA levels of adenomas were significantly higher (P<0.05) than of flat mucosa in the same group, but both showed great variability from patient to patient. Our findings suggest that the mRNA levels of methyltransferase cannot be used as predictive marker for screening in families affected by hereditary colon carcinoma. Received: 20 July 1998 / Accepted: 21 September 1998     

CK20 expression in the gastrointestinal tract of the embryo and fetus]

A novel type of cytokeratin, cytokeratin 20 (CK20), was added in 1990 to the classic catalog of human cytokeratins, a heterogeneous group of proteins present in almost all epithelia. In man, the expression of CK20 is almost entirely confined to the gastro-intestinal epithelium, to the urothelium and to Merkel cells. Since only few data are available regarding the expression of CK20 in the developing human intestinal mucosa, we studied CK20 immunoreactivity in fetal and neonatal human gut. Immunoreactivity for CK20 was tested in fetuses and newborns, from the twelfth up to the fortieth week of gestation. In each subject, a specimen from the oesophagus, stomach, small intestine, colon, appendix was studied. Tissue samples were routinely processed and paraffin sections were stained with the CK20-specific antibody IT-Ks 20.8. CK20 immunoreactivity was absent in the oesophageal epithelium and it was unevenly distributed in the gastrointestinal mucosa. Three main patterns of immunoreactivity were observed during normal development: the first, found in the stomach and in the small bowel, is characterized by a progressive increase in CK20 expression during gestation; the second pattern, found in the duodenum, shows a progressive decrease in CK20 expression during gestation; in colon and appendix (third pattern), we did not find significant changes in the degree of immunoreactivity for CK20 during gestation. CK20 is unevenly expressed in developing human intestinal mucosa. The degree of positivity for CK20 appears to be related to the epithelial maturation stage only in gastric and small bowel mucosa. Further studies are needed to verify if the uneven CK20 immunoreactivity in the gastrointestinal tract persists even in adulthood.