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Biomedical subjects

M Ludwig

Publications and source records attributed to M Ludwig.

At least 253 records · Page 14Linked to original sources
PubMed1991

Detection and characterisation of two missense mutations at a cleavage site in the factor VIII light chain.

Haemophilia A is an X-linked bleeding disorder caused by a deficiency of factor VIII. As an essential cofactor in the intrinsic clotting cascade, factor VIII is activated and subsequently inactivated by proteolytic cleavages involving factor IIa (thrombin), factor Xa and activated protein C (APC). Investigation of the thrombin cleavage sites at amino acids 372 and 1689 of the factor VIII protein by oligonucleotide screening, DNA amplification and direct sequencing, enabled us to identify two missense mutations in 441 unrelated haemophiliacs. A C-to-T transition, which leads to the substitution of cysteine for arginine at position 1689, was found in a severely affected patient and a previously undescribed G-to-A substitution, causing replacement of arginine1689 with histidine, was found in a patient with mild disease.

Base Sequence↗
PubMed1991

Pro-347-Arg mutation of the rhodopsin gene in autosomal dominant retinitis pigmentosa.

It has been shown recently that autosomal dominant retinitis pigmentosa may be caused by point mutations of the rhodopsin gene in a portion of families. In this communication, a large six-generation family with autosomal dominant RP is described. Molecular analysis by PCR amplification followed by restriction digestion or heteroduplex analysis suggested a point mutation in codon 347, in which two different mutations (Pro-347-Ser and Pro-347-Leu) have already been reported. Direct sequencing of the patients' DNA revealed a previously undescribed CCG----CGG transversion in codon 347 predicting a Pro----Arg substitution. Ophthalmological data of the patients are summarized and compared to those of patients with other mutations in the rhodopsin gene.

Base Sequence↗
PubMed1991

[Autosomal dominant hereditary retinopathia pigmentosa with genetic heterogeneity].

There is considerable clinical variability in autosomal dominant retinitis pigmentosa (ADRP). The underlying biochemical defect had remained unknown until recently, so that it was not possible to determine the primary cause(s) of this phenotypic diversity. Recently, different point mutations and base pair deletions have been identified in the rhodopsin gene in a proportion of patients with ADRP, providing convincing evidence for allelic genetic heterogeneity in this disease. We screened a total of 65 patients with ADRP in Germany, Austria, and Switzerland for the presence of the point mutations described recently at codons 58 and 347 in patients in the USA. Our results show that the frequency of point mutations at codon 347 in the patients studied here is about 3%, a figure similar to that found in the USA. The frequency of the mutation at codon 58 seems to be generally low. The identification of patients with point mutations in the rhodopsin gene offers the possibility, for the first time, of studying the correlation between genotype and disease phenotype.

Chromosome Aberrations↗
PubMed1991

[Contribution for the method of testing the shearing strength of metal ceramic bonding system].

The shown method of testing the shearing strength of metal ceramic bonding systems has proved in connection with the development of metal ceramic materials and their handling as an efficient technique, which leads to reproducible results with a small dispersion. In divergence from the method of Schmitz and Schulmeyer we use material layers in a bigness, which allow usual laboratory manufacturing techniques and above it the bonding strength of single cera layers can be estimated.

Dental Bonding↗
PubMed1990

[Experiences with the use of an intravascular 6 French endosonography catheter in vivo].

Further progress in intraluminal sonography has led to the development of a 6 French ultrasound imaging catheter. This report demonstrates in vivo results using this new technique in a swine. Intraluminal echographic images obtained from the aorta and iliac arteries were of good quality. Artifacts such as image distortion were related to the 20 Mhz mechanically rotating tip motion and caused a loss of image quality. Atherosclerotic lesions could be visualized. The characteristics of the echo image of an atherosclerotic lesion related to the composition of corresponding histological sections of the lesion. Intraluminal sonography may develop into a new diagnostic tool, further enhancing progress in atherosclerosis research and improving the evaluation of coronary arteries and perivascular structures. Combined use with balloon angioplasty might also improve invasive therapeutic procedures.

Animals↗
PubMed1990

Carcinoma of the lower lip with perineural extension to the middle cranial fossa.

An 81-year-old man had left labial paresthesia and a palpable mass adjacent to the left mental foramen 6 months after apparent adequate excision of a small (1.5 cm) primary squamous cell carcinoma of the left portion of the lower lip. Biopsy and clinical evaluation revealed recurrent squamous cell carcinoma. Subsequent left hemimandibulectomy confirmed perineural extension of tumor along the mandibular branch of the trigeminal nerve to the foramen ovale. Seven months later, the patient died of complications resulting from intracranial extension of tumor to the left cerebellopontine angle. This case illustrates the lethal potential of carcinoma of the lip due to contiguous perineural extension, even with a small primary tumor and absence of regional lymph node metastases.

Aged↗
PubMed1990

[Juvenile occlusion syndrome of the inferior vena cava with left renal deficiency].

In three juvenile patients, one female and two males aged 14 to 21 years, there were recent deep vein thromboses of the lower limbs due to previous infrahepatic occlusion of the inferior vena cava associated with a shrunken left kidney without clinical manifestation of a nephrotic syndrome. Possible reasons and impacts of this probably congenital peculiar vascular syndrome are discussed. Radiodiagnostic management in juvenile patients with recurrent venous thromboses of the lower part of the body is explained with special respect to secondary phenomena of other retroperitoneal organs like adrenals, inner pelvis and testicles.

Adolescent↗
PubMed1989

[Bencyclane in stage II arterial occlusive disease. Results of a controlled study].

In a single-center, double-blind, randomized study, 19 patients with peripheral arterial occlusive disease stage II Fontaine were treated with bencyclan, and a further 19 patients with buflomedil for 10 weeks after a wash-out phase of 2 weeks. Both groups showed a significant increase in painfree and total walking distances. No significant difference was found between the two groups.

Aged↗
PubMed1989

[Diagnosis and differential diagnosis of swollen leg].

Leg swelling is often of edematous nature. The most important differential diagnosis lies in the distinction between venous or lymphatic forms of edema. An increased vascular permeability and alterations in blood composition have also to be taken into account. A particular entity is the lipedema. Next to an accurate history, specific inspection and palpatory criteria permit to distinguish the various forms. Tests for venous function, laboratory and technologically investigative techniques increase diagnostic accuracy. Lymphedema can only be diagnosed by an exact clinical diagnosis.

Diagnosis, Differential↗
PubMed1989

[Diagnosis of very early arteriosclerosis vascular changes using Duplex sonography].

The technical evolution of ultrasonic equipment provides a high resolution imaging analysis of the vessel wall and thereby offers new possibilities in diagnosing very early atherosclerotic changes. The typical B-mode image in human and animal arteries shows parallel wall contures enclosing a hypoechoic space. In this study in Vitro- and in Vivo-experiments in rabbit aortas document the distance between these contures correlating histologically with a high cholesterol diet caused a broadening of the hypoechoic space in the rabbit aortic vessel wall. The data demonstrate that high resolution Duplex Sonography is a usefull noninvasive approach for the detection of very early atherosclerotic changes in arterial vessel walls in a stage before plaques can be identified.

Animals↗