Search PubMed⌕ Search

Biomedical subjects

H Walther

Publications and source records attributed to H Walther.

At least 55 records · Page 3Linked to original sources
PubMed1995

Molecular simulation of 8-styrylxanthines.

Regarding theophylline as representative xanthine derivative, it was shown that the net charges of various semiempirical quantum chemistry methods are transferable by scaling. PM3 should be preferred for calculation of xanthine derivatives. Molecular modelling indicated that there is a conformational similarity of the lead structure of xanthine and adenosine derivatives. The substituents bound to the C8 of xanthine and to the C2 of adenosine derivatives are involved in the discrimination into adenosine A2 antagonists and agonists. The A2 affinity of xanthines is mainly determined by the type of N7 substitution (hydrogen/methyl), the lipophilic substituent constant related to the C8 substituents, and the dipole moment of the molecules. To simulate chemically the A1 affinity, a further term (lowest unoccupied molecular orbital energy) must be added. In addition, hydrogen-bonding forces were hypothesized using a newly synthesized 3,6-diaminocarbazole derivative as synthetic adenosine pseudoreceptor.

Adenosine↗
PubMed1994

[Leiomyosarcoma of the stomach].

Leiomyosarcoma of the stomach is a rare occurrence, amounting to only 0.5-3% of all stomach malignancies. Because of its extragastral growth, it produce clinical symptoms, mostly with bleeding, only at a late stage. The decisive method of examination is computed tomography which demonstrates the extraluminal tumor lying apparently in the mesenterium with contrast medium up-take at the borders and central necrosis. A secure differential diagnosis to leiomyoma is not possible by angiography or by computed tomography; this distinction is even difficult by histology.

Adult↗
PubMed1993

[Abdominal actinomycosis].

Twelve years after adnexectomy, performed for actinomycosis of the left ovary, a 32-year-old woman developed abdominal and back pain. A solid tumour was palpated in the left lower abdomen. Colon contrast examination revealed a subtotal stenosis in the sigmoid colon, while sonography showed a complete stenosis of the left ureter with left hydronephrosis. Relaparotomy demonstrated a stone-hard tumour at the rectosigmoid junction, which involved the right ovary and ureter, as well as having infiltrated the retroperitoneum, predominantly on the left. After resection of the sigmoid colon, uterus and right ovary, as well as of the ureteric stenosis with reanastomosis, the further course was without complication. Histological examination confirmed actinomycosis of the left ovary, sigmoid colon and pelvic mesocolon. Therapy with amoxycillin, 500 mg three times daily, was started. As the patient had worn an intrauterine pessary for several years, primary infection of the uterus with spread into the abdominal cavity via tube and ovaries is likely to have been the course of events. The recurrence was probably caused by reactivation of residual actinomycetes in the retroperitoneum and pelvic mesocolon.

Abdomen↗