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Biomedical subjects

M Clemens

Publications and source records attributed to M Clemens.

At least 37 records · Page 2Linked to original sources

Further delineation of the Baller-Gerold syndrome.

Three new patients with the Baller-Gerold syndrome bring the number of reported cases to 20. In addition to craniosynostosis involving various sutures and preaxial reduction defects of variable severity, affected patients may have anal, urogenital, cardiac, central nervous system, and vertebral defects. Autosomal recessive inheritance is supported by the presence of affected sibs and parental consanguinity.

Abnormalities, Multiple↗

Homologous and illegitimate recombination in developing Xenopus oocytes and eggs.

Exogenous DNA is efficiently recombined when injected into the nuclei of Xenopus laevis oocytes. This reaction proceeds by a homologous resection-annealing mechanism which depends on the activity of a 5'-->3' exonuclease. Two possible functions for this recombination activity have been proposed: it may be a remnant of an early process in oogenesis, such as meiotic recombination or amplification of genes coding for rRNA, or it may reflect materials stored for embryogenesis. To test these hypotheses, recombination capabilities were examined with oocytes at various developmental stages. Late-stage oocytes performed only homologous recombination, whereas the smallest oocytes ligated the restriction ends of the injected DNA but supported no homologous recombination. This transition from ligation to recombination activity was also seen in nuclear extracts from these same stages. Exonuclease activity was measured in the nuclear extracts and found to be low in early stages and then to increase in parallel with recombination capacity in later stages. The accumulation of exonuclease and recombination activities during oogenesis suggests that they are stored for embryogenesis and are not present for oocyte-specific functions. Eggs were also tested and found to catalyze homologous recombination, ligation, and illegitimate recombination. Retention of homologous recombination in eggs is consistent with an embryonic function for the resection-annealing mechanism. The observation of all three reactions in eggs suggests that multiple pathways are available for the repair of double-strand breaks during the extremely rapid cleavage stages after fertilization.

Animals↗

[Halogenated organic compounds in swimming pool water].

18 different swimming pool waters in the Bonn-Rhein-Sieg area were analysed for trihalogenmethanes, halogenated acetic acids, 2,2-dichloropropionic acid, dihalogenacetonitriles and chloral hydrate. Most substances mentioned above were determined in almost every sample reaching total concentrations up to 538 micrograms/l. Considering the results one can see that some of the main pollutants are polar organic compounds like di- and trichloroacetic acid as well as chloral hydrate.

Acetonitriles↗

[Magnetic resonance imaging in knee injuries].

Of all the diagnostic imaging techniques for the injured knee, Magnetic Resonance Imaging (MRI) has been shown the most worthwhile. Indications for standard X rays, arthrography and ultrasonography are briefly reviewed. Advantages of MRI, the technical aspects and the sequences used are explained. After a short description of the signals of all the common anatomic components of the knee, we describe MR findings in meniscal pathology, tenoligamentous lesions and cartilage and bone injuries.

Humans↗

[Effect of propyphenazone on drug biotransformation in the liver. A comparison with phenylbutazone using the aminopyrine breath test].

By means of the aminopyrine breath analysis the influence of phenylbutazone, propyphenazone and of the combination preparation Wofapyrin "new" on the aminopyrine-N-demethylation, a hepatic microsomal performance of biotransformation in patients with diseases of the rheumatic circle of forms was examined. The enzyme-inducing effect of phenylbutazone known from literature could be confirmed. On the other hand despite a relatively highly dosed one-week treatment propyphenazone did not lead to changes of the demethylation capacity of the liver in the majority of the patients. In individual cases increases of the capacity are possible. In general, however, the doses of propyphenazone usual in the practice for the treatment of acute feverish infections no disturbing effects of induction or inhibition on the metabolic liver functions represented by the amino-N-demethylation are to be expected. The enzyme-inducing effect of Wofapyrin "new" is to be ascribed to the phenyl-butazone component.

Aged↗

Interstitial and terminal deletions of the long arm of chromosome 4: further delineation of phenotypes.

We reviewed 45 patients with a deletion of the long arm of chromosome 4. Forty-one were previous reports (25 terminal deletions and 16 interstitial deletions) and 4 are new cases with terminal deletions. Of the 29 patients with terminal deletions, 18 with deletion at 4q31 and 4 at 4q32----qter had an identifiable phenotype consisting of abnormal skull shape, hypertelorism, cleft palate, apparently low-set abnormal pinnae, short nose with abnormal bridge, virtually pathognomonic pointed fifth finger and nail, congenital heart and genitourinary defects, moderate-severe mental retardation, poor postnatal growth, and hypotonia. Six patients with a deletion at 4q33 and one patient with deletion 4q34 were less severely affected. In general, patients with various interstitial deletions proximal to 4q31 had a phenotype that was less specific, although mental retardation and minor craniofacial anomalies were also present. There were 3 patients with piebaldism and one with Rieger syndrome. We conclude that terminal deletion of chromosome 4q (4q31----qter) appears to produce a distinctive malformation (MCA/MR) syndrome in which the phenotype correlates with the amount of chromosome material missing and which differs from the more variable phenotype associated with interstitial deletions of 4q.

Abnormalities, Multiple↗

Immune phagocytosis inhibition by commercial immunoglobulins.

Sixteen commercially available immunoglobulins (Ig) and 5 anti-Rho (D) hyperimmune globulins were investigated for immune phagocytosis inhibition (IPI) factors as well as for T, B lymphocytotoxic and monocytotoxic antibodies. All Ig contained IPI factors with lowest inhibitory IgG concentrations ranging from 0.08 to 50 mg/ml. Pepsin-digested Ig was noninhibitory. IPI factors in anti-D preparations were uniformly high (inhibitory IgG concentrations 0.6-2.5 mg/ml). Cytotoxic antibodies against T, B lymphocytes and monocytes were found in 2,2 and 7 products, respectively. Since we have recently shown that IPI is caused by antibodies against major histocompatibility complex antigens, most likely HLA, the hypothesis is put forward that IPI factors in Ig are HLA-related, cytotoxic as well as noncytotoxic antibodies which act via Fc receptor blockade of human monocytes.

B-Lymphocytes↗

Autocrine growth of human B lymphocytes: maintained response to autostimulatory factors is the special feature of immortalization by Epstein-Barr virus--a hypothesis.

The autocrine growth profile of human B lymphocytes transformed with Epstein-Barr virus (EBV) was found to comprise three distinct components: a B-cell growth factor (BCGF); an interleukin-1 (IL-1)-like activity; an activity requiring cell-to-cell contact for its action. Observations on the inhibition of the EBV-carrying Daudi lymphoma line by alpha-interferon indicated that loss of response to these autostimulatory factors was underlying growth cessation. Furthermore, a putative receptor for BCGF was found to be down-regulated on B cells stimulated with non-transforming mitogens but constitutively expressed following EBV-transformation. Taken together with recent evidence that normal B cells produce autostimulatory factors, these findings suggest that the special feature of autocrine growth by EBV-immortalized cells is a maintenance of what should normally be a transient phenotype, possibly through deregulation of receptor expression. This hypothesis is discussed.

B-Lymphocytes↗

[Perioperative staging and the Münster TNM classification in ampullary and pancreatic cancer].

From 1974 to 1982 607 patients with diseases of the pancreas were treated at the Surgical University Clinic of Münster/West Germany. 256 of those suffered from pancreatic and 42 from ampullary cancer. All patients were grouped according to a TNM-System for pancreatic cancer developed for that particular purpose. Of the curative resections performed (n = 73) with a resection rate of 78.6% for ampullary and 15.6% for pancreatic cancer, a distinct preponderance of early stages (T1N0M0/T2N0M0 greater than 60%) was noticed for the first, of late stages for the latter (T1N0M0/T2N0M0 = 25%). The frequencies of distant metastases for all operations also differed significantly, being 9.5% respectively 43.4% at the time of operation (p less than 0.05). At the low mean survival time for palliative operations an mean survival time of 40.3 months for the Whipple operation was evaluated, of 28.0 months for total pancreatectomy. At the stage T1N0M0/T2N0M0 the mean survival time was greater than 63 months.

Ampulla of Vater↗