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J Stoffel

Publications and source records attributed to J Stoffel.

8 recordsLinked to original sources
PubMed2000

Molecular analysis of PTEN and MXI1 in primary bladder carcinoma.

Loss of heterozygosity (LOH) on 10q is associated with late-stage events in urothelial neoplastic progression. The tumor suppressor gene PTEN, which is mutated or homozygously deleted in numerous cancers, maps to a region of 10q within the reported region of minimal loss in bladder tumors. In two recent studies alterations in the PTEN gene occur at a low frequency in bladder tumors displaying 10q LOH. We have screened 35 late-stage bladder tumors for mutations in PTEN and MXI1, both genes mapping to chromosome 10q. Using single-strand conformation polymorphism analysis, we identified 6 tumors harboring mutations in PTEN and 2 additional tumors displaying homozygous deletion at this locus. No MXI1 mutations were identified within the same tumor panel. Of 16 bladder tumor cell lines analyzed, 2 showed homozygous deletion of PTEN and 3 harbored point mutations resulting in an amino acid change. Two cell lines harbored missense mutations in MXI1. We report a significantly higher frequency of PTEN alterations in bladder carcinoma (23%) than was previously recorded, with no accompanying mutations in the MXI1 gene.

Amino Acid Substitution↗
PubMed2000

[Tumor surgery of the upper cervical spine].

Our own series of tumors of the upper cervical spine was analyzed retrospectively. The standard treatment strategies were reevaluated. A total of nine patients (mean age 61 years, metastasis 4, plasmocytoma 3, chordoma 1, histiocytosis 1) were treated between 1/92 and 2/99. A total of 12 operations were carried out. One-step procedures (6): Three extraoral, one transoral, one dorsal and in one case combined dorsal and extraoral tumor removal were performed. Three dorsal occipitocervical or atlantoaxial stabilizations, one ventral plating and two combined ventral plating plus dorsal three-point fixations, and four vertebral body replacements were carried out. Two-step procedures (3): three extraoral tumor removals with ventral plating plus dorsal three-point fixation, in combination with vertebral body replacement in two cases. The neurological status and the quality of life (Karnofsky performance status, pain levels) were analyzed preoperatively and at the follow-up outpatient examinations (mean follow-up: 18 months). Flexion-extension radiographs were performed at the follow-up. There was no operative mortality. The transient morbidity was 11%. The operative intervention improved the quality of life in all patients. Three patients died within 27 months of operation. Tumor resection at the upper cervical spine using individually modified surgical strategies over an approach corresponding to the tumor location, stabilization and vertebral body replacement increases significantly the time of survival and quality of life with an acceptable surgical risk for complications.

Atlanto-Axial Joint↗
PubMed1977

Experimental reimplantation utilizing microvascular anastomosis in animals.

The use of the operating microscope and special microsurgical instruments make it possible to achieve successful anastomosis of blood vessels of less than 1 mm in diameter. Microvascular surgery offers newer possibilities in the transplantation of dermisfat grafts, and has led to an unusually high degree of success in the reimplantation of tissues. This paper describes a technique for microvascular anastomosis in animal experiment, using as a model the reimplantation of a completely amputated rabbit ear. In 10 amputated rabbit ears, the central auricular artery with a diameter of 0.5 mm and the two marginal auricular veins with diameter of 0.5-1.0 mm were microsurgically anastomosed. Of the 10 reimplanted ears, 8 survived. The postoperative angiogram showed an unrestricted patency of all the vessels.

Animals↗
PubMedDate not supplied

Contractile properties of slow and fast muscle following tourniquet ischemia.

Tourniquet application is commonly used during surgery on an extremity to create a bloodless field. Investigations have focused on the ultrastructural, histochemical, and biochemical effects of tourniquet ischemia on muscle. Few studies, however, have examined the influence of tourniquet ischemia on the contractile properties of muscle. The purpose of this study was not only to examine this latter consideration, but also to determine whether slow and fast muscles exhibit a differential response. In adult male guinea pigs, the plantaris and soleus muscles of control (N = 5) and experimental legs (N = 5) were tested for time-peak-tension (TPT), one-half relaxation time (1/2RT), maximal twitch tension (Pt), and maximal tetanic tension (Po). The experimental leg was subjected to a 2 hour tourniquet which was placed around the thigh. Muscles of this leg were tested following a 2 hour recovery period. In three of the five animals, no response could be elicited from either the plantaris or soleus muscles of the experimental leg. In those instances where the experimental muscles were capable of generating force, the plantaris was clearly more effected. While tension production in the soleus was reduced by approximately 55%, the plantaris exhibited approximately a 90% decrease in tension output. Furthermore, both TPT and 1/2RT demonstrated consistent changes. These results indicate that the contractile properties of both the soleus and plantaris are dramatically effected by a 2 hour tourniquet. They further suggest that there may be a differential response based upon fiber type.

Animals↗