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Biomedical subjects

J Becker

Publications and source records attributed to J Becker.

At least 307 records · Page 17Linked to original sources
PubMed1981

Age-dependent anatomical changes in an identified neuron in the CNS of Aplysia californica.

Neurons of Aplysia californica are naturally pigmented and the pigment accumulates with age. In the present study the pigment was examined in the same neuron from Aplysia of three postmetamorphic ages: young, sexually mature, and old. The large central neuron, R2, was examined by light and electron microscopy to determine if the pigment possessed properties similar to lipofuscin pigment seen in aging mammalian neurons. We used the same microscopic techniques that demonstrate the presence of lipofuscin in mammalian neurons. Light microscopic studies demonstrated a regional correlation between autofluorescence, staining with Sudan Black, and the naturally occurring pigment in old R2s. Electron microscopic studies revealed the presence of large vacuolated and lamellated membrane-bound bodies in the peripheral cytoplasm of old R2s, similar to those found in mammalian neurons. The bodies were located in the same region in which autofluorescence and Sudan Black staining were observed. Although the naturally occurring pigment accumulates with age, it acquires characteristics of lipofuscin pigment in the neurons of older sexually mature animals. The presence of these pigment characteristics can be used as an index of aging in Aplysia neurons as they are in mammalian neurons.

Aging↗
PubMed1981

Capsular constriction of the hip: arthrographic and clinical considerations.

Orthodox radiological examination of patients presenting with disorders of the hip, usually on account of pain and limitation of movement, may vary in diagnostic value. As a supplementary study we have employed arthrography. During this procedure we have, since 1970, routinely assessed the capacity of the joint capsule. The normal capacity varies from 20 ml in a large adult male to 14 ml in a small adult female. Significant reduction of this volume has been observed as a secondary complication of certain organic lesions, including four cases of synovial chondromatosis, one case of an intra-articular loose body, and one case of osteoid osteoma of femoral neck. In these secondary cases, the only common feature visible on the plain film was regional osteopenia. In these patients symptoms persisted until adequate surgical measures had been performed. (Descriptive term proposed: secondary capsular constriction of the hip: SCCH). In another group of seven patients, in whom orthodox radiological studies were unrewarding, arthrography was undertaken on account of persistent pain and limitation of movement. Similar reduction in the capacity of the joint was found, but in each case spontaneous resolution of the symptoms took place, without surgical intervention, in periods varying from three to 18 months. This self-limiting syndrome appears to be analogous to that of the "frozen shoulder" and, like the latter, is associated frequently with barbiturism.

Adult↗
PubMed1981

CBF--computer handling of chemical and biological facts.

CBF is an EDP-supported documentation and retrieval system for structural formulas of defined organic compounds and their biological activities. It fits the needs of a firm concerned with drug research for prevailing unpublished internal data, which the scientists can use for reflections on structure-activity relationships and to search for lead compounds with specific activity profiles.

Biology↗
PubMed1981

Inpatient evaluation of aggression in psychiatric patients.

The authors rated violent and violence-related behavior of patients on a psychiatric intensive care unit, and found that despite the restricted environment such behaviour was manifested to a considerable degree. The amount of violent behavior was significantly correlated with admission Brief Psychiatric Rating Scale ratings on measures of thought disorder and schizophrenic thinking, but not with ratings of hostility.

Adult↗
PubMed1981

Ultrastructural study of rat liver and liver neoplasms after long-term treatment with phenobarbital.

The purpose of this investigation is to study the ultrastructure of liver and liver neoplasms after long-term administration of phenobarbital. Liver from female Charles River rats treated with 0.1% sodium phenobarbital by dietary admix for 60, 180, or 113 weeks was examined; liver neoplasms present at 108 or 113 weeks were also examined. At 60 weeks, an outstanding feature of most hepatocytes was the extensive proliferation of smooth endoplasmic reticulum, increase in autophage vacuoles, lysosomes, blebbing, and Kupffer cells containing phagosomes. At 108 or 113 weeks, additional changes in liver included an abundance of myelin figures in vacuoles, sinusoids, and bile canaliculi and the occasional appearance of whorls of smooth endoplasmic reticulum. Hepatocytes from liver neoplasms, all identified as well-differentiated hepatic cell neoplasms, contained voluminous whorls and large phagosomes filled with whorls, myelin figures, and cellular debris. The phagosomes were present both intracytoplasmic and intrasinusoidal, either partially or completely surrounded by Kupffer cell extensions. These cellular alterations are interpreted as evidence of adaptive cellular responses.

Age Factors↗
PubMed1980

Electrical alternans of the ST segment in non-Prinzmetal's angina.

Elevated electrical alternans of the elevated ST segment (STEA) was documented in a patient with non-Prinzmetal's or classical angina and severe atherosclerotic coronary artery disease. STEA was precipitated during graded exercise testing. The disappearance of this phenomenon after aortocoronary bypass surgery suggests that the coronary obstructions were the etiologic factors. These findings emphasize that the STEA may occur in myocardial ischemia caused by conditions other than Prinzmetal's angina.

Action Potentials↗
PubMed1980

Dynamics of endogenous catecholamine release from brain fragments of male and female rats.

A continuous flow perifusion system was used to measure the in vitro release rate, and percent release of endogenous norepinephrine (NE) and dopamine (DA) from rat brain fragments. Catecholamines (CA) were measured simultaneously in effluent fractions and in tissue fragments following perifusion using a modified radioenzymatic assay. Employing this perifusion system allows not only quantification of endogenous release, but also permits study of the dynamics of the release process. To validate the system, NE and DA release were measured in effluent from medial basal hypothalamus (MBH) and caudate nucleus (CN) fragments under various temperature and ionic conditions. K+-stimulated release (60 mM KCl), but not the basal release rate, is temperature and calcium dependent. Marked regional differences are seen in the parameters considered. DA release rate from the CN in male rats was 30 times greater than from the MBH. The percent of DA release was 2.5 times greater and there was a 3 times greater final tissue concentration of DA in the CN than in the MBH. Although the release rate of NE from CN fragments was higher than that of the MBH, it did not reach statistical difference. However, the percent of NE release from the CN was close to 4 times greater than the percent release from the MBH, and final tissue concentrations of NE were 87.9 pg/mg in the CN compared to 1,240 pg/mg in the MBH (postperifusion values). In a group of female rats, only the percent release of NE from the MBH was significantly different from that of similar tissue from male rats. However, the release rate and percent release of DA from the MBH of female rats were significantly lower than that of male rats. In appears that under this in vitro condition there are marked regional and sex differences in the metabolism of CA between the CN and the MBH fragments of male and female rats. Implications of these findings are briefly discussed.

Animals↗
PubMed1980

Elimination of excess smooth endoplasmic reticulum after phenobarbital administration.

Livers from Charles River rats during and after treatment with phenobarbital were studied in order to investigate possible mechanisms involved in the elimination of excess smooth endoplasmic reticulum. The most pronounced structural change during compound administration was proliferation of smooth endoplasmic reticulum; depletion of glycogen and an increase in lipid deposits were also observed. After termination of treatment, these changes were reversed. The appearance of an increased number of autophage vacuoles and lysosomes plus the localization of acid phosphatase reaction product in these bodies suggests autophagy as one possible mechanism for the elimination of excess smooth endoplasmic reticulum. Cytoplasmic blebs and fragments replete with smooth endoplasmic reticulum were observed within the sinusoids. The presence of Kupffer cell cytoplasmic extensions surrounding these fragments and acid phosphatase reaction product within Kupffer cell inclusions suggests heterophagy as another process participating in the removal of excess smooth endoplasmic reticulum.

Animals↗
PubMed1980

[Model investigations regarding the spread of local anaesthetics in isobaric spinal anaesthesia (author's transl)].

The better to comprehend isobaric spinal anaesthesia, we constructed a thermoregulated model of the subarachnoid space. With it we investigated the six not exactly isobaric local anaesthetics bupivacaine, carticaine, lidocaine, mepivacaine, prilocaine and tetracaine, in order to determine the effect of the following factors on their spread: injected volume, position, density, temperature of the injected solution, rate of injection, barbotage, direction of the spinal needle and its opening. The injected volume was most important. The small differences in density were of consequence in the vertically mounted model. Higher rates of injection increased the spread. The remaining factors were not relevant. The investigation corroborates the clinical observation that spinal anaesthesia with approximately isobaric solutions is a well controllable technique.

Anesthesia, Spinal↗
PubMed1979

[Role of vitamin B 12 in the incorporation of ribonucleosides into the DNA of various Periplaneta americana cell lines].

Hemocytes and non hemocytes in vitro cell lines from Periplaneta americana, have been tested for their ability to incorporate, in the presence of vitamin B 12, various nucleic acid precursors into their DNA. Evidence was shown for enhanced transformation of all ribonucleotides into deoxyribonucleotides in the presence of vitamin B 12. Moreover, in hemocyte cell lines, it was demonstrated that vitamin B 12 produced an activation of thymidine kinase activity.

Adenosine↗
PubMed1979

Serial quantitation of in vitro lymphocyte responsiveness to concanavalin A.

Eight normal donors were serially tested over a period of 1 to 7 months for their in vitro lymphocyte responsiveness (IVLR) to 50 microgram of concanavalin A (Con A) per ml. 3H-Thymidine incorporation was monitored by routine scintillation counting and compared to actual numbers of proliferating cells (lymphoblasts) as measured by laser (flow) cytometry. Determination of total cell numbers or lymphoblast numbers was found to be superior (P less than 0.0001 and P less than 0.001, respectively) to 3H-thymidine incorporation as a measure of serial stability.

Blood Cell Count↗
PubMed1979

[Density of cerebrospinal fluid and local anesthetics (author's transl)].

The densities of cerebrospinal fluid and of local anesthetics, applicable to isobaric spinal anesthesia, were determined by using the Digital Density Meter DMA 02. The density of CSF showed little variation and at 37 degrees C was 1.00021 +/- 0.00024 g/cm3 (mean +/- SD, n = 22). The density of the local anesthetics bupivacaine 0.5%, carticaine 2%, lidocaine 2%, mepivacaine 2% and prilocaine 2% varied at 25 degrees C between 1.001 and 1.005 g/cm3, at 37 degrees C between 0.997 and 1.001 g/cm3. Tetracaine 0.5% in CBF increased its density by 0.00046 g/cm3. The addition of the vasoconstrictors adrenaline and ornipressine (POR 8) increased the density of the local anesthetic solutions insignificantly. On the basis of the narrow range of variation of CSF density, reliable statements may be made on the density dependent spread of local anesthetics in spinal anesthesia.

Anesthesia, Spinal↗