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Biomedical subjects

G Neumann

Publications and source records attributed to G Neumann.

At least 109 records · Page 6Linked to original sources
PubMed1981

Characterization of retinoic acid-induced alterations in the proliferation and differentiation of a murine and a human melanoma cell line in culture.

We employ the murine S91 and the human Hs939 melanoma cell lines for the characterization of various biochemical changes induced by retinoids. Retinoic acid (RA) causes a time-dependent, and reversible reduction in cell proliferation rate in liquid medium and inhibits growth in agar. The proportion of cells in the G1 phase of the cell cycle increases in RA-treated cells, and the uptake of TdR, UdR and Leu decreases. The growth inhibitory effect of RA is apparently not mediated via labilization of lysosomes, increase in cAMP or changes in the synthesis of prostaglandins or polyamines. Exposure to RA stimulates tyrosinase activity and increases melanin content severalfold over the levels found in untreated cells. Various retinoids exhibit the activities of RA; however, their potencies vary depending on their structure. Those possessing a free -COOH at C-15 are usually more effective than those with a different group or with a derivatized carboxyl. A positive correlation exists between the ability of retinoids with a free -COOH in C-15 to inhibit growth and to bind to an RA-binding protein found in the S91 melanoma cells. Future studies will explore recently discovered changes in the glycosylation of cell surface components and their relationship to the phenomena described here.

Animals↗
PubMed1981

Prolonged opacification of the gallbladder after oral cholecystography: a reevaluation of its clinical significance.

The frequency of prolonged opacification of the gallbladder after oral cholecystography was determined in several conditions that are manifestly or reputedly associated with gallbladder dysfunction: in patients with gallstones, in cases of "biliary colic" with normal cholecystograms, in postvagotomy patients, and in diabetics. These groups were compared with asymptomatic controls and to patients with irritable bowel syndrome. A dietary fat intake of at least 50 g between the first and last films taken was ensured in all subjects. The effect of fat deprivation was separately studied in asymptomatic controls. Prolonged opacification was encountered in approximately two-thirds of patients with gallstones, in two-thirds of patients with "acalculous biliary colic," in two-thirds of healthy subjects deprived of fat, and in about one-third of postvagotomy patients and diabetics. It was not seen in a single patient with irritable bowel syndrome, and it was encountered in only 1 out of 17 controls whose diet included a fat supplement. These differences were highly significant (p less than 0.0001).

Adult↗
PubMed1981

[Detection and therapy of rectal cancer (author's transl)].

The state of detection and therapy of rectal cancer in the capital of Berlin is compared with that in the rural region of Neubrandenburg. The trend and regional differences between metropolitan and rural areas were investigated. It was shown that a population-based cancer registry yields useful information. The proportion of new cases in old age increased; stage distribution showed a tendency towards earlier detection; operative treatment became more aggressive and more successful. However, the state of detection and management was found to remain still better in the metropolitan area than in the rural region.

Adult↗
PubMed1981

[Myocardial scintigraphy with Tc-99m-diphosphonate in patients with coronary heart disease: a comparison with ECG and hemodynamic examinations at rest and during exertion].

In 67 patients, 61 of whom underwent a myocardial infarction and 6 suffered from angina pectoris, myocardial scintigraphy was performed using the technetium-99m-diphosphate (Tc-99m-DP). In 51 patients the ECG and left pulmonary end-diastolic pressure (LPEDP) were investigated additionally at rest and during exercise (bicycle ergometre). A significantly higher occurrence of positive scintigrams was found in cases with marked coronary insufficiency, whereas with the normal ECG findings the negative scintigrams were significantly more often. Increased LPEDP values occurred more often with positive than with negative myocardial scintigrams, especially during exercise. The authors recommend the myocardial Tc-99m-DP scintigraphy for the assessment of the activity of pathologic process after acute myocardial infarction.

Angina Pectoris↗
PubMed1981

[Changes in circulatory parameters in dogs under general respiratory hypoxia].

The decrease in the oxygen content of the inspired air calls forth enhanced demands on the cardiocirculatory performance. In experiments on healthy dogs the haemodynamic shifts connected with short-term hypoxia were investigated, with particular attention to the possible presence of irreversible changes in the myocardium. With the aid of radiocardiography the following parameters were investigated before, during and after hypoxic test: blood volume, cardiac output, stroke volume, heart frequency, ejection fraction, mean right-to-left circulation time, and segmental lung volume. In dependence on the degree of hypoxia characteristic changes in the above parameters occurred. After the end of hypoxia most parameters returned to their initial levels. The presence of irreversible changes could not be proved. Under the given conditions, it was possible to test the individual level of cardiocirculatory performance with the aid of hypoxia similarly as by using the exercise test.

Animals↗
PubMed1980

[Myocardial scintigraphy using technetium-99m-diphosphate in combination with selective coronary perfusion scintigraphy and coronary angiography].

The findings of the scintigraphy of the myocardium with Technetium-99m-diphosphonate (Tc-99m-DP) of 45 patients with nearly exclusively ischaemic heart disease were compared with those of the selective coronary angiography and those of the selective coronary perfusion scintigraphy. 12 patients exhibited an enlargement of the activity in the myocardium (positive scintigramme). These cases were particularly described in this paper. The levocardiogramme proved disturbances of the motility of the walls in 6 patients. In 5 patients a positive scintigramme of the myocardium was registered. Therefore, the scintigraphy of the myocardium with Tc-99m-DP is regarded as a supplementing, non-invasive method for the diagnosis of more pronounced disturbances of the motility of the heart wall. Furthermore, positive scintigrammes of the myocardium were registered in angina pectoris, condition after aorto-coronary bypass-operation, cardiomyopathy and myocarditis. Since the scintigraphy of the myocardium with Tc-99m-DP is a sensitive method for the poor of cell lesions of the myocardium, it allows a judgment of the floridity of the myocardial process. From this among other results that the scintigraphy of the myocardium may be a help for the indication to the aorto-coronary bypass operation. Clear relations between the scintigraphy of the myocardium, the number of the coronary-sclerotically changed heart vessels and the development of stenosation are not to be established. An immediate connection between the size of the disturbance of the perfusion and the results of the scintigraphy of the myocardium is also not to be recognized.

Adult↗
PubMed1980

[Relation of vaccination to childhood malignancy].

74 German legitimate children who have died 1972/73 by a malignant neoplasm did not differ significantly from healthy controls by their vaccination history. This holds true for vaccination against tetanus, poliomyelitis, smallpox, and tuberculosis. By BCG-vaccination neither a promoting nor a protecting effect could be discovered. Controls were more often vaccinated against diphtheria than cases.

Adolescent↗
PubMed1980

Characterization of activity of alkaline phosphatase (AAP) in capillary endothelium of normal and psoriatic skin.

The activity of alkaline phosphatase (AAP) in papillary capillaries of normal and psoriatic skin was characterized by enzyme inhibition studies. Quantitatively, there were pronounced differences between normal and psoriatic skin, i.e., increase of AAP, as determined by a grading system, and assimilation of the strength of AAP in venous and arterial side of the capillary loop in psoriasis. Qualitatively, the inhibition studies with different actin inhibitors revealed no difference between AAP in normal and psoriatic skin or between initial, fully developed and healed psoriatic lesions as well as noninvolved skin of psoriatics. Thus, the physiologic AAP seems to be stimulated in psoriasis. Generally, AAP of dermal capillaries is highly sensitive to cysteine inhibition.

Alkaline Phosphatase↗
PubMed1980

A new highly potent and short-acting analgesic, carfentanyl (R 33799), in combination with the hypnotic agent, etomidat (R 26490), as a method of anaesthesia in guinea pigs.

Anaesthesia in guinea pigs with a new highly potent and short-acting analgesic, carfentanyl (R 33799), combined with the hypnotic, etomidat (R 26490), is reported. Clinical observations as well as respiratory and circulatory variables have revealed this combination to be safe. Profound surgical anaesthesia has been obtained with good sedation, analgesia, and immobilisation. This method has been evaluated clinically and can be recommended with confidence in this species.

Anesthesia↗
PubMed1980

Effects of monocular deprivation in the lateral geniculate nucleus of the cat: an analysis of evoked potentials.

The effects of monocular deprivation on excitatory post-synaptic activity in the lateral geniculate nucleus and on the afferent activity to the geniculate in the cat were examined. Field potentials elicited by electrical stimulation of the optic nerves were recorded and analysed. This approach revealed that the most severe effects of deprivation originate at the input stage to the lateral geniculate nucleus. 1. The membrane currents resulting from excitatory post-synaptic activity in the geniculate are at least a factor of two smaller in amplitude in the deprived than in the non-deprived laminae, indicating a severe reduction of synaptic strength. This effect is equally pronounced for activity mediated by the X- and the Y-system and has to be considered as the major origin of the imbalance of activity from the deprived and non-deprived eye apparent in cortex. 2. Judged from amplitudes and latencies of compound action potentials in the optic tract, afferent Y-activity is not affected by deprivation. This indicates that the number of afferents from the retina of the deprived eye to the geniculates is not significantly reduced by deprivation. 3. During several periods of recording conduction block in the afferents from both eyes was observed.

Animals↗