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Biomedical subjects

H Becker

Publications and source records attributed to H Becker.

At least 433 records · Page 24Linked to original sources
PubMed1986

[Immunomodulating therapy of collagen diseases].

The treatment of connective tissue disorders still proves problematic. Most forms of therapy are based on empirical data because of a lack of specified therapy regimes. The time period, during which controlled studies have been performed, was brief. Furthermore, the spectrum of diseases and drugs investigated has been inadequate. The uncertainty regarding the therapeutics, however, is confronted by a number of powerful and high-risk drugs. As a result of a better understanding of the immunoregulatory mechanisms and advances in the development of drugs, the original concept of nonselective immunosuppression has been replaced by attempting the influence of specific parameters. Cortisone is still considered to be of basic importance for the treatment of most of these diseases. Other available drugs are immunosuppressives such as azathioprine, methotrexate, cyclophosphamide, chlorambucil, and D-penicillamine. New developments include the use of cyclosporine A, high-dose immunoglobulins, plasmapheresis, antithymocyte globulins, levamisole, inosiplex, and radiation of lymph nodes. A causal specific therapy, other than for rheumatic fever, is not in sight. In order to find a form of therapy which is disease-specific, low-risk and with a high success rate, long-term controlled studies on large groups of patients need to be performed.

Adrenal Cortex Hormones↗
PubMed1986

[High-resolution computerized tomography as a supplementary examination prior to cochlear implants].

Patients must be thoroughly tested for their suitability for a cochlear implant. Promontory testing and electrocochleography are of fundamental importance. It is possible to distinguish sensory deafness from other forms by combining the results of both tests. The implantation of intracochlear electrodes requires exact information of the anatomy of the cochlea, the tympanic wall of the cochlea and the endocochlear space. This can be assessed by axial high resolution computed tomographic scans. 8 of 70 patients were inoperable because of cochlea lesions (fractures or malformations). The advantage of computer tomography compared to conventional tomography is the fact that radiation exposure is less while the resolution is nearly the same. If computer tomography and conventional tomography do not reveal any fractures an exploratory tympanotomy should precede the cochlear implant operation in patients with a history of cranio-cerebral trauma.

Audiometry, Evoked Response↗
PubMed1986

[Comparative quantitative clinico-chemical analysis of the characteristics of 24-hour urine and morning urine].

Ten clinical chemical parameters were used to investigate the relationship between morning urine and 24-hour urine in 80 healthy probands. During the period of the investigation there were no dietary restrictions. A period of at least 4 hours was required between the previous micturation and the collection of morning urine. The following parameters were determined: sodium, potassium, chloride, creatinine, urea, uric acid, glucose, calcium, inorganic phosphorus and total protein. Every parameter, with the exception of total protein, was determined without prior manual dilution, by a fully mechanized procedure, using a multichannel analyser SMA 12/60 (Technicon) adapted for routine purposes. The data showed: The scatter of the excretory values is generally lower in 24-hour urine than in morning urine, but collectively the reference intervals are relatively wide. Almost without exception, there is a significant correlation between excretion in the 24-hour and morning urines, but the average correlation coefficient is only 0.5. The determined reference intervals (10/90 percentile) for the concentrations of the parameters in 24-hour and morning urines are largely in agreement. It is concluded from the data that the composition of morning urine of apparently healthy probands adequately reflects excretion of 24 hours. It remains to be seen whether this is also true for pathological states.

Adult↗
PubMed1985

Further investigations of valepotriates in the Valerianaceae.

Four species of Valeriana from Costa Rica and Peru were analysed for valepotriates: V. pulchella, V. priophylla, V. condamoana and V. micropterina. The highest amount of total valepotriates was found in the rhizomes of V. prionophylla.

Chromatography, High Pressure Liquid↗
PubMed1985

Effects of converting enzyme inhibitors: ramipril and enalapril on peptide action and sympathetic neurotransmission in the isolated heart.

The role of converting enzyme (CE) in heart function was studied by assessing the inhibition of CE activity in rat heart tissue and in isolated perfused hearts from rat, guinea-pig and rabbit (Langendorff technique). Angiotensin I (ANG I) added to the perfusate reduced coronary flow (FLO) in all species, increased force of contraction (CON) in rats, decreased CON in guinea-pigs and had no effect on CON in rabbits. In contrast, bradykinin (BK) increased FLO in all species, decreased CON in rats, increased CON in guinea-pigs and had no effect on CON in rabbits. The CE inhibitors ramipril (HOE498) 1 mg/kg and enalapril (MK421) 30 mg/kg given orally 1 h prior to killing of the animals inhibited the ANG I effects and potentiated the BK effects but had no effects on the action of ANG II. The same doses of the two CE inhibitors produced up to 24 h inhibition of CE activity measured biochemically in the heart after single oral doses. Electrical sympathetic stimulation of the cardiac nerves (SNS) in isolated rabbit heart resulted in an increase of HR and CON and in an initial decrease and subsequent increase of FLO. The effects of SNS on HR and FLO were significantly reduced following HOE498 (1 mg/kg) pretreatment. The results suggest that local CE is involved in the regulation of peptide effects in the heart, including the ANG II-mediated facilitation of neurotransmission.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1985

[Hemorrhagic pancreatitis: effect of dextran 40 and plasma on microcirculation disorders of the pancreas].

A dog model was used to measure the hemodynamic changes occurring during acute pancreatitis induced by intraductal injection of fresh trypsin-bile-blood mixture. Continuous measurements of pancreatic blood flow, cardiac output, mean arterial blood pressure and pancreatic oxygen consumption were made under normal conditions and during acute pancreatitis. All animals received 100 ml of saline/h during the time of observation. Three methods of therapy then were instituted in the dogs starting 30 min after induction of pancreatitis. 10 dogs served as controls (saline 100 ml/h); in 6 dogs additionally 15 ml/kg plasma was infused over 45 min and 6 dogs received 1.5 ml/kg Dextran 40/h continuously. Hemorrhagic pancreatitis was characterized by a fall in cardiac output and mean arterial pressure and the development of severe impairment of the pancreatic microcirculation with early reduction of pancreatic blood flow followed by a fall in pancreatic oxygen consumption. Administration of plasma produced a significant increase in cardiac output; however, blood pressure and pancreatic blood flow remained low. Low-molecular weight Dextran has no influence on cardiac output, but significantly improved the blood pressure and leads to a normalization in pancreatic blood flow and oxygen consumption. These results suggest that low-molecular weight Dextran appears to reverse the impairment of microcirculation and hypoxia of the pancreas and limits the progression from edematous to hemorrhagic pancreatitis and irreversible pancreatic damage.

Animals↗
PubMed1985

The effect of infusions of 5 alpha-dihydrotestosterone or estradiol-17 beta on the concentration of some steroids in the human testicular vein and artery.

The concentrations of testosterone, 5 alpha-dihydrotestosterone, 5 alpha-androstan-3 alpha, 17 beta-diol, 5 alpha-androstane-3 beta, 17 beta-diol, estradiol-17 beta and testosterone-glucosiduronate were measured in the plasma of the testicular vein and artery simultaneously with the estimation in peripheral venous and arterial plasma 60 min after an infusion of 3000 micrograms dihydrotestosterone (DHT) or estradiol (E2), respectively, in patients undergoing orchiectomy for prostatic cancer. The results were as follows; following infusion of DHT or E2, both steroids were completely metabolized by the testes. After DHT the testicular secretion of E2 was significantly reduced. In peripheral plasma 3 alpha-diol concentration was increased. Following E2 a transient elevation of testosterone in the spermatic vein was observed, whereas a slight decrease of DHT and an increase especially of 3 beta-diol levels occurred. It is assumed that DHT as well as E2 plays a role as intratesticular regulator of steroid synthesis and metabolism.

Aged↗
PubMed1985

Doppler frequency spectrum analysis and digital subtraction angiography in carotid artery disease.

The aim of the study was to evaluate the diagnostic accuracy of frequency spectrum analysis complementary to direct Doppler sonography in comparison to conventional biplane arteriography and transvenous digital subtraction angiography in internal carotid artery stenosis. In a group consisting of 229 carotid arteries visualized by conventional biplane arteriography, Doppler frequency spectrum analysis had a specificity of 97% and concerning all stenoses and occlusions, a sensitivity of 89%. In a second group consisting of 198 carotid arteries imaged by transvenous digital subtraction angiography, Doppler sonographic examination had a specificity of 65% only, and concerning all categories of stenoses and occlusions a sensitivity of 85%. These differences concerning specificity are not interpreted as false positive diagnoses in Doppler spectrum analysis but are considered to be due to false negative findings of digital subtraction angiography in stenoses of less than 50% vessel diameter reduction.

Carotid Artery Diseases↗
PubMed1985

[Comparative MR and CT research in selected neuroradiological problems].

Magnetic resonance (MR) is a new digital imaging method which is of particular interest in the radiological diagnosis of the central nervous system. It provides a new form for demonstrating the brain and the spinal cord. To evaluate the scope of the method, it was compared with CT. The results in patients with epilepsy of unknown origin, cerebral infarcts, sellar space-occupying lesions and spinal angiomas are described. MR provides information concerning tumours causing epilepsy and also fresh infarcts at an earlier stage than CT. MR has not, so far, provided any new insights in the diagnosis of sellar tumours or spinal angiomas. In these cases, MR can, nevertheless, compete with CT and with conventional radiological methods. Present experience, particularly with problem cases, indicates that MR is becoming an important method of examination in neuroradiology.

Adult↗
PubMed1985

[11C-methionine PET, IMP-SPECT, CT and MRI in brain tumors].

11C-labelled L-methionine uptake was measured in 7 patients with brain tumours prior to surgery, and in 2 patients with infarction, using PET. The strongest uptake occurred in tumours with a high grade of malignancy (astrocytoma IV: Tumour/Non-Tumour T/NT = 2.6) while low-grade tumours accumulated less activity (astrocytoma II: T/NT = 1.4). Conventional 99mTc DTPA scans revealed a damage of blood brain barrier (BBB) in 4 patients (2 infarctions) with no or only slight 11C-methionine accumulation, while one patient with negative 99mTc-scan and negative CT accumulated methionine in the tumour region (astrocytoma II). PET, MRI, and CT are complementary with regard to extent of tumour tissue, necrotic areas and oedema. None of the brain tumours or infarcted regions took up IMP (123I amphetamine). The investigated regions showed definite uptake defects ranging from 10-50% if compared with the contralateral side. In view of the chemical pathway of methionine it is concluded that the uptake reflects metabolic activity in brain tumour tissue rather than a diffuse uptake due to BBB damage.

Amphetamines↗
PubMed1985

[NMR and CT studies in acute and late-stage cerebral infarct].

MR offers an additional non-invasive means for the investigation of cerebro-vascular disease. This new digital imaging method competes with CT. Twenty-four patients with cerebral infarcts were examined by CT and MR; of these, 12 were in the acute stage of necrosis and resorption, and 12 were examined after six weeks following the formation of cysts and glial scars. Because of the increased relaxation time of T1 and T2, there is a large signal difference between infarcted and normal brain. Consequently, cerebral infarcts can be clearly recognised during the first 24 hours. MR also has advantages in demonstrating infarcts in the pons and medulla and if one wishes to avoid contrast enhancement during CT. Problems may arise in differentiating fresh infarcts from haemorrhage and from gliomas. At the present time, the length of the procedure and its high cost justify MR in exceptional circumstances only.

Cerebral Infarction↗
PubMed1985

[Computer tomography in diagnosis of ovarian cancer].

In 90% of all cases an ovarian tumor about 2 to 3 cm in size can be visualized computertomographically using a contrast medium. Determination of the dignity can be achieved in about 81% of all cases. Malignant tumors which are impressive as smooth-walled cysts are only recognized as such in 50% of all cases. Correct staging also occurs in 50% of all cases. An accuracy of about 90% can be expected in aftercare.

Calcinosis↗
PubMed1985

Differential effects of central angiotensin II and substance P on sympathetic nerve activity in conscious rats. Implications for cardiovascular adaptation to behavioral responses.

The centrally induced effects of angiotensin II and substance P on the cardiovascular system and on neuronal efferent activity of the splanchnic, renal, and adrenal nerves were investigated in chronically instrumented conscious rats. The pressor responses to substance P injected into the lateral brain ventricle were accompanied by marked and short latency increases in heart rate, cardiac output, splanchnic, renal, and adrenal nerve activity, and a rise in plasma noradrenaline and adrenaline. Behaviorally, an arousal-type reaction was observed. In contrast, the pressor responses to intracerebroventricular angiotensin II were associated with initial decreases in heart rate, cardiac output, splanchnic, renal, and adrenal nerve activity, and a fall in plasma noradrenaline at the time of the maximal blood pressure increase. In some but not all animals, a second blood pressure peak associated with increases in heart rate and splanchnic nerve activity was observed after several minutes. Incomplete chronic sinoaortic baroreceptor deafferentiation prevented the angiotensin II-induced fall in heart rate but not the initial fall in splanchnic nerve activity. The decreases in splanchnic nerve activity also occurred in diabetes insipidus rats and persisted in Long Evans rats after vascular vasopressin receptor blockade with d(CH2)5AVP, despite marked reductions of the pressor responses in both groups. Peripheral alpha-adrenoceptor blockade with prazosin or ganglion blockade with hexamethonium inhibited the central angiotensin II pressor responses only in combination with vasopressin receptor blockade. On the other hand, either sympatholytic drug, alone, abolished the pressor responses in the diabetes insipidus rats. This indicates that in intact conscious rats the central pressor effects of angiotensin II are initiated by vasopressin release but become dependent on the sympathetic nervous system when vasopressin is absent or not effective. When rats were allowed to drink in response to angiotensin II, a further sharp rise in blood pressure occurred, together with increases in heart rate and splanchnic nerve activity. The results demonstrate fundamental differences in the mechanisms by which central pressor peptides can influence cardiovascular and autonomic function. It is conceivable that the distinct sympathetic response patterns to central angiotensin II and substance P receptor stimulation form part of a specific cardiovascular adjustment to the individual behavioral reactions, such as drinking, as in the case of angiotensin II, or arousal within the central processing of pain, as in the case of substance P.

Action Potentials↗