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Biomedical subjects

A Horn

Publications and source records attributed to A Horn.

At least 109 records · Page 6Linked to original sources
PubMed1985

Intralumenal alkaline phosphatase of the calf intestine.

About 80% of the total activity of the alkaline phosphatase of the calf intestine was found within the lumen and only 20% in the mucosa. The specific activity of the intralumenal enzyme fraction was about ten times higher than that of the mucosa enzyme. Differential centrifugation experiments demonstrated that the intralumenal enzyme of the proximal gut segment can be found in a fraction which exhibits sedimentation behaviour like a microsomal fraction, whilst the intralumenal enzyme of the distal gut segment was found to be soluble in the supernatant after centrifugation at 135000 X g for 60 min. Ouchterlony double diffusion analysis and antibody inhibition of alkaline phosphatase by antisera against the mucosa enzyme demonstrate that the two forms of intestinal enzyme have apparently identical antigenicity. Purified alkaline phosphatase obtained from the intralumenal fraction and from mucosa exhibits closely related pH-optima, Michaelis constants, amino acid inhibition type and inhibition constants. The results of large scale release of alkaline phosphatase bound to microvesicles are discussed with regard to results of morphological investigations in different tissues and cell cultures demonstrating the formation of intestinal membrane bodies and cell extrusion.

Alkaline Phosphatase↗
PubMed1984

Radiotherapy and resection for apparently inoperable rectal adenocarcinoma.

Sixty-seven patients with primary, apparently inoperable rectal adenocarcinomas were referred for radiotherapy from a defined geographic region in Norway during the period from 1976 to 1981. Fifty-five were without detectable metastasis at referral and were potentially resectable. Patients were given high energy radiation towards abdominal chimney or pelvic fields to a dose of 3150 rads. Resection was attempted after three weeks. Additional radiotherapy was given to both resected and nonresected patients to a NSD (nominal standard dose) of 1400 to 1560 ret (rad equivalent therapy). At full radiation dose, nonresected patients were reexamined, and in some explorative laparotomy with resection was attempted. Twenty patients had radical resections in the pelvis, but five of them had moderately advanced distant metastasis. Nine patients are disease-free at 12+ to 76+ months. Although the overall prognosis for the patients with apparently inoperable rectal adenocarcinomas remains poor (median survival 12 months), some patients can achieve long-term disease-free survival after combined radiotherapy and surgery. Patients with moderately advanced metastasis can enjoy a better of quality of life without local symptoms following the combined treatment.

Adenocarcinoma↗
PubMed1984

Follow-up of patients with large bowel cancer: a critical evaluation.

A study of 102 consecutive patients hospitalized for large bowel cancer in the period 1975-1976 was performed to evaluate the hospital's follow-up programme in such cases. The overall five-year survival rate was 32%. New pathologic changes (previously unknown malignant or benign tumour) were found in 42% of the patients. The incidence of new pathology was highest among patients with tumours of Dukes' category C, followed by Dukes' B and A, respectively. The probability of new pathology detection was high in the first two years after primary operation for colonic cancer and thereafter the risk seemed to be small. This phenomenon appeared to be general, irrespective of Duke's stage and whether or not curative resection had been performed. Consumption of hospital resources did not seem to prolong patient survival, most resources being used for patients with short survival. More emphasis should be placed on detection of operable metastatic disease, or curable synchronous and metachronous pathology within the first two years after curative resection for large bowel cancer.

Adult↗
PubMed1983

Uptake and release of [3H]dopamine by the median eminence: evidence for presynaptic dopaminergic receptors and for dopaminergic feedback inhibition.

The accumulation and release of [3H]dopamine by the median eminence in vitro was studied after treatments with different pharmacological agents, to determine whether such a procedure would be useful for measuring neuronal activity in the tuberoinfundibular dopaminergic system. The accumulation of [3H]dopamine was temperature, time, and sodium dependent, and reduced by unlabelled dopamine and by a potent dopamine uptake blocker, nomifensine. The outflow of tritium was studied after blocking the oxidative deamination of dopamine by nialamide. The outflow of tritium was elicited consistently by biphasic square wave electrical pulses and by high molarity potassium ions. The response to electrical stimulation was dependent largely on calcium and partially on sodium. The response to high molarity potassium ions was reduced in the absence of calcium ions. The response to electrical stimulation was increased by nomifensine and by a dopaminergic antagonist, haloperidol, and was reduced by dopamine and by a dopaminergic agonist, piribedil. The inhibitory action of dopamine was antagonized by haloperidol. These results indicate the existence of uptake and release mechanisms in the tuberoinfundibular dopamine neurons, and suggest that dopamine may inhibit its own release via dopaminergic receptors. This in vitro method may be useful for measuring dopamine uptake and release by tuberoinfundibular dopaminergic neurons.

Animals↗
PubMed1983

[Course and stage control in testicular tumors using alpha 1-fetoprotein determination].

The serum AFP level of 52 patients with testicular tumours was measured using an ultra-micro-ELISA technique. The results confirm the importance of an uninterrupted observation of this marker in order to judge the course of the therapy of nonseminomatous testicular tumours. 85% of the patients with nonseminomatous testicular tumours showed positive values. AFP measurement is also important for staging. The assay used is precise, cheap and suitable for serial measurement.

Castration↗
PubMed1983

External fixation of pelvic fracture ex vivo.

Cranial dislocations of the fractured hemipelvis is the most difficult component to reduce and control by external fixation. The stabilizing effect of several external frames was studied using a cadaver pelvis. Single frames, double frames, trapezoid frames and double trapezoid frames were mounted in three pin units on each anterior iliac crest. Successively increasing the number of transverse connecting rods increased the stability of the construction. Wiring of the symphysis had the same effect, when constructions with one or two transverse rods were used. Double fixation sites of the pin units in the anterior pelvis added only marginally to the stability. The highest rigidity was achieved using a circumferential frame with pin units in both anterior and posterior iliac crests.

Bone Nails↗
PubMed1982

Intraoperative autotransfusion.

Intraoperative autotransfusion (IAT) was proposed in 1818 by Blundell. In 1968 Klebanoff introduced the modern IAT system (Bently ATS-200) which can suck blood from the operative field and infuse up to 900 ml/min into the patient again. Ten patients in this series were autotransfused a median of 2275 ml blood during aortoiliac surgery for occlusive arterial disease. Blood samples taken before, during and after surgery showed no significant changes attributable to IAT, except for a minor decrease in the platelets. Total heparinization for elective vascular surgery and citrate (ACD or CPD) for emergencies is recommended. IAT was found safe, easy to operate, efficient in handling large quantities of blood and relatively inexpensive. Furthermore autotransfused blood--in contrast to bank blood--has a normal content of platelets and labile clotting factors.

Adult↗
PubMed1981

Dynamic properties of a phosphofructokinase/pyruvate kinase system. Experiments in vitro using the substrate-stat technique.

It is known from theoretical work that very simple enzyme systems may exhibit non-linear dynamic properties like those found in vivo. To realize such a system experimentally, an ATP-producing reaction (pyruvate kinase) was coupled with an ATP-consuming reaction (phosphofructokinase). The substrate-stat technique has been adapted to characterize each single enzyme as well as to follow up one enzyme in the coupled system. If the plots of both pyruvate kinase activity versus [ADP] and phosphofructokinase activity versus [ATP] are hyperbolic, the coupled system approaches a unique steady state as predicted from the single characteristics. Under assay conditions where phosphofructokinase is inhibited by ATP, its characteristics as found in a single assay and in the coupled system are different. For a system with ATP-inhibited phosphofructokinase, a paradoxical behaviour is predicted and is demonstrated experimentally. If the total pyruvate kinase activity is increased over a certain limit, the system is switched from a low [ATP], high-activity steady state into a high [ATP] low-activity steady state.

Adenosine Diphosphate↗
PubMed1980

Improvements of the chamber analysis.

Improvements of the chamber analysis directed to increase the sensitivity by introduction of fluorescence assays, to facilitate the handling of the procedure and to increase the accuracy by introduction of automatic data processing and partially automatized volume dispensing for 50 microliter volumes simultaneously are described. The method is used for measuring of enzyme activities and substrate concentrations in 2--30 microliter sample volumes with final assay volumes lower than 100 microliter. Two variants of the procedure are presented. With variant I all steps of the analysis including start of the reaction by mixing, incubation and measuring are carried out in the measuring chamber. With variant II the measuring chamber is used for the measuring process only, the other steps are performed outside in special chambers. Application examples from biochemical and clinical chemical analysis are demonstrated.

Acetylglucosaminidase↗