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Biomedical subjects

J Arndt

Publications and source records attributed to J Arndt.

At least 37 records · Page 2Linked to original sources
PubMed1990

The status of trypsin-like enzymes in squamous-cell carcinoma of the head and neck region.

The activity of two proteases associated with tumour cells was studied using frozen sections of squamous-cell carcinoma and fluorescent probes for the enzymes. Four fluorescent probes were used to define the enzymic status of guanidinobenzoatase on the surface of the squamous carcinoma cells. Each of four probes demonstrated the location of cells possessing inactive guanidinobenzoatase, whereas adjacent cells of the same tumour exhibited active enzyme. It was shown that the inactive form of the enzyme was an inhibitor-enzyme complex that could be dissociated. In contrast, all of the squamous carcinoma cells possessed active trypsin-like enzymes that were recognised by fluorescent aprotinin molecules. The observed variation in enzymic status of these two tumour-associated enzyme systems is discussed in the context of a possible biological control mechanism for cell migration.

Aminacrine↗
PubMed1989

Inhibition of a protease associated with tumour cells and the probable mechanism of regulation of this interaction in vivo.

The regulation of activity of a protease on the surface of human colonic tumour cells implanted in nude mice has been studied. A synthetic fluorescent probe was used to locate cells possessing active guanidinobenzoatase in frozen sections of tumour bearing tissues. These studies demonstrated the presence of intracellular protein inhibitors of guanidinobenzoatase which could be extracted in isotonic saline and transferred to the outer surface of the tumour cells. This study showed that the inhibition of guanidinobenzoatase was pH dependent and that the tumour cell may regulate the activity of its surface guanidinobenzoatase by exporting lactic acid.

Animals↗
PubMed1986

Stereotactic radiation therapy of intracranial arteriovenous malformations.

Twenty-six patients with large intracranial arteriovenous malformations (AVM), not suited for open surgery or radiosurgery, have been treated by fractionated stereotactic radiation therapy using a linear accelerator. The preliminary results are based on follow-up angiography one and a half years after treatment, and in 5 cases also 5 years after treatment. In 2 cases a complete obliteration of the AVMs has occurred, and in the majority of the remaining cases a reduction of the size of the lesion has been obtained. Further development of the method is needed in order to improve the results. Today treatment with this technique is only recommended in cases which cannot be treated with other methods.

Adolescent↗
PubMed1986

[Histologic changes in the normal bladder wall following fractionated irradiation--an animal experimental study].

The histopathologic alterations of the bladder wall were investigated in 180 rabbits irradiated with different fractionations and total focal doses. Animals sacrificed on week after the end of irradiation showed alterations of the urothelium (desquamation, increased polymorphism of nuclei vacuolizations) as well as oedematous and hyperemic reactions in submucosa and muscularis. These alterations became stronger when the single and total focal dose and the ret value were increased. Animals sacrificed three to six months after the end of irradiation showed dystrophic-sclerotic processes as well as vascular obliterations in the submucosa and muscularis. The alterations were only clearly visible in case of a total focal dose of at least 30 Gy. With regard to a minimization of histopathologic alterations of the bladder wall, a fractionation of 1.5 Gy per day has to be considered as favorable in radiotherapy of the carcinoma of the urinary bladder.

Animals↗
PubMed1985

[Results of percutaneous radiotherapy of bladder cancer using 1 and 2 series of irradiation].

In a randomized prospective clinical study, the authors investigate the results of percutaneous radiotherapy (telecobalt) with two rhythms of fractionation in patients with vesical carcinomas. A one-series irradiation with 1.5 Gy daily (except the weekends) up to a total dose of 60 Gy is compared to a two-series irradiation (in the first series 3 Gy three days per week up to 30 Gy, then irradiation-free interval of four weeks, in the second series 1.5 Gy daily up to a total focal dose of 60 Gy). The five-year survival rates are 52% after one-series irradiation and 39% after two-series irradiation. The surgical treatment consisted in a most radical resection of the vesical tumor by TUTUR, partial resection of the wall, of transvesical tumor resection.

Aged↗
PubMed1985

[Results of radiotherapeutic optimization within the scope of combined operative-radiologic therapy of urinary bladder cancer].

The results of a prospective randomized clinical study for the comparison of a uniserial irradiation with a biserial irradiation are demonstrated. The investigations were performed on altogether 191 patients. Patients after cystectomy and supravesical by-pass of the urine were excluded. The operative treatment consisted of TUTUR, transvesical tumour resection or partial resection of the urinary bladder. According to the life table method the uniserial irradiation a survival rate of 52% and for the biserial irradiation of 39% after 54 months was calculated.

Aged↗
PubMed1984

Effects of 16,16 dimethyl prostaglandin E2 on irradiation damage of the small intestine.

The effects of oral 16,16 dimethyl prostaglandin E2 on irradiation induced damage of the small intestine was examined in the rat. Groups of Sprague-Dawley rats received graded doses of the analogue or placebo at 24, 8 and 0.5 hours before and at 16 and 24 hours following whole abdominal exposure to 10 Gy. Rats were killed 72 hours after irradiation. Pretreatment within the lower dose range had a moderate protective effect with better preserved crypts and crypts to villus ratio. Larger doses seemed to increase the intestinal damage. The prostaglandin treated sham irradiated rats had higher villous height and larger epithelial surface compared with controls.

16,16-Dimethylprostaglandin E2↗
PubMed1984

Corneal wedge resection in rabbits.

Corneal wedge resection was performed on 30 albino rabbits. There was a significant increase in astigmatism produced when the width or length of the wedge was increased.

Animals↗
PubMed1983

Stereotactic radiosurgery in cases of acoustic neurinoma: further experiences.

Fourteen patients with acoustic neurinomas varying in size from 7 to 30 mm were treated by stereotactic radiosurgery and then were followed for 4 years. The tumors of eight patients decreased 1 to 10 mm in diameter, no change was found in two, and the tumor increased slightly in three patients. Loss of the ability to enhance with contrast administration on computed tomographic scan was a common effect of the treatment. One patient in poor general condition died from intercurrent disease 6 months after radiosurgery. At postmortem examination, a large central necrosis was found. Among five patients with hearing before treatment, full preservation was demonstrated in one; in the other four, the mean impairment of speech discrimination score was 43%. One patient with total unilateral deafness regained hearing and achieved a discrimination score of 60% at 1 year after treatment. There was transient facial weakness in five patients, which was detectable only by electromyography in one. Facial hypesthesia appeared in two patients and was transitory in one of them. Thirteen of the patients are in good or excellent general condition. Stereotactic radiosurgery offers the only therapeutic alternative to open operation in the management of acoustic neurinomas. It is worth considering for every patient, but especially for poor risk patients and those with bilateral tumors.

Adult↗
PubMed1983

[Results of the treatment of cervical cancer at the Department of Medicine of the Friedrich Schiller University in Jena 1965-1976. II. Combination of surgery and percutaneous radiation therapy].

Based on a material of 1502 patients with carcinoma of cervix uteri, treated between 1965 and 1976 in gynaecological-radiological teamwork in the Department of Medicine at the University of Jena, we report on 304 cases of primary operation and following radiation therapy with telecobalt. The 5-year-survival rate of all cases in this group is 78,6%, the rate of recurrences 14,1%.

Adult↗
PubMed1981

[Early experience with repeated determinations of 131-I-hipuran clearance-equivalent during pregnancy ].

Serial observations of ureteric and renal function during pregnancy were carried out by using isotope clearances; renal scintigraphy was performed for the first examination and isotope nephrography subsequently. The results of both types of examination are tabulated. It is shown that these procedures provide the necessary information on renal and ureteric function, given the indications which we have listed. The information concerns both kidneys or can be confined to a single kidney.

Adolescent↗