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Biomedical subjects

M Lenz

Publications and source records attributed to M Lenz.

At least 73 records · Page 4Linked to original sources
PubMed1993

[Gigantic pyohydronephrosis and contralateral ureteral bud. Problems of differential diagnosis].

Both giant hydronephrosis and blind-ending ureteral bud are rare conditions. We report on a patient with an impacted ureteral stone leading to giant pyohydronephrosis (6.51) on the right side, which in turn caused displacement of the ureter containing the stone to the left. An asymptomatic blind-ending ureteral bud initially complicated the diagnosis. After nephrectomy, a unsuspected transitional cell carcinoma of the right renal pelvis and the ureter was found.

Carcinoma, Transitional Cell↗
PubMed1992

Isolation, sequencing and expression in E. coli of the urocanase gene from white clover (Trifolium repens).

The urocanase gene was detected in a clone obtained from a genomic library of white clover. The entire gene has been sequenced and expressed in the pT7-7/E. coli BL 21 (DE 3) system. The deduced sequence of the plant urocanase is 72% homologous with that of the well-characterized urocanase from Pseudomonas putida. The purification procedure, as well as kinetic and electrophoretic behaviour, of the new enzyme are described.

Amino Acid Sequence↗
PubMed1992

Computed tomography (CT) and magnetic resonance imaging (MRI) in T-stage evaluation of oral and oropharyngeal carcinomas.

174 CT and 32 MRI investigations were carried out on patients with carcinomas of the mouth and oropharynx. The methods were compared and their value in predicting the pre-therapeutic T-staging studied. The combination of CT and clinical examination was able to improve the T-staging considerably compared with clinical examination alone. MRI was superior to CT in delineating the tumour margins in 78% of patients. T1-weighted and gradient echo sequences after intravenous gadolinium injection were particularly useful. Nevertheless, T-staging based on clinical and CT-findings was changed in only 5% of patients by MRI. MRI is especially useful in T1 tumours and in cancer of the base of the tongue. MRI should also be used instead of CT were dental fillings obscure the region of interest. If there are good MRI facilities and an experienced team available MRI can be used before CT.

Diagnostic Errors↗
PubMed1991

[Diagnosis and therapy of aggressive fibromatosis (extra-abdominal desmoid) in the head and neck area].

Desmoid tumours (extraabdominal desmoids, aggressive fibromatosis) are rare connective tissue tumours, that grow infiltratively and destructively. The analysis of the course of disease in three patients suffering from desmoid tumours in the head and neck region (regio submandibularis, regio parotidea, parapharyngeal space) confirmed the data in literature that painless swelling and dysfunction are the first non-specific signs of the disease. Morphologically reactive fibromatosis and fibrosarcoma should be considered (amongst others) in differential diagnosis. CT and MR scans are useful in determining the extent of the tumours and help to distinguish the tumour from nerves, vessels and bone. Surgery is the therapy of choice in the head and neck region. Primary surgery was performed in our patients. Due to recurrences two of our patients have been operated on several times including major plastic reconstructive surgery. One patient died three and a half years after primary treatment due to sarcomatous degeneration. A large parapharyngeal recurrence was successfully reduced by percutaneous radiation therapy in our second patient. Follow-up of our third patient was NAD 15 months after resection of a large parapharyngeal/mediastinal process including blocking of two cervical vertebrae. Summing up, desmoid tumours are rare connective tissue tumours in the head and neck region with a destructive biological behaviour similar to malignant tumours and a high recurrence rate. Surgery is the treatment of choice. In recurrences or if the tumour is not properly resectable, radiation must be considered, whereas the chemotherapeutical approach is not yet well established.

Adult↗
PubMed1991

Overcorrection as an academic remediation procedure. A review and reappraisal.

Overcorrection procedures traditionally were designed to reduce the behavioral excesses of persons with mental retardation. However, beginning with a study of Foxx and Jones (1978), it became clear that variations of the procedure could be used to enhance academic proficiency in students with average intelligence, borderline intelligence, learning disabilities, and various levels of mental retardation. Studies were reviewed in this article that have used overcorrection procedures to enhance academic proficiency, and it was concluded (a) that overcorrection, alone or combined with positive reinforcement, significantly increased the academic proficiency of the students, and (b) that the label "overcorrection" is inappropriate, given that the procedures described in these studies did not meet the criteria for overcorrection procedures. It was suggested that overcorrection procedures used for academic remediation be called directed rehearsal in the future to reflect more accurately the procedures actually used.

Achievement↗