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Biomedical subjects

G Adam

Publications and source records attributed to G Adam.

394 records · Page 22Linked to original sources

The coordination of heart beat and respiration during ergometric stress in patients with functional cardiovascular diseases.

Patients with functional cardiovascular diseases were tested during a rectangular ergometric stress protocol for the reaction of the frequency coordination (n = 82) and the phase coordination (n = 52) of heart beat and respiration. The ratios of the pulse and respiratory frequency converged increasingly with the duration of the exercise, caused by a similar reaction of the respiratory rates.

Adolescent↗

[MRI-controlled outcome after core decompression of the femur head in aseptic osteonecrosis and transient bone marrow edema].

PURPOSE: We evaluated the signal changes of avascular necrosis and transient bone marrow oedema before and after core decompression of the femoral head to deduce prognostic factors for this operative procedure. METHOD: 38 to 40 cases with core decompression (35 patients, medium age 44 years) were analysed with a mean follow-up time of 26 months. Preoperatively patients were staged by the ARCO classification. MR-images were judged in accordance to the criteria of Mitchell and Steinberg. The clinical outcome was analysed according to the hip index of Merle D'Aubigne. RESULTS: All hips with transient bone marrow oedema showed normal signal patterns at an average of 3 months after core decompression. In stage I and II, all patients with a preoperative necrosis area less than 30% of the femoral head showed a reduction of the necrotic zone and good clinical results. An unchanged or progressive appearance was observed in necrotic lesions with more than 30% head involvement. Because of failure a renewed operation had to be done in all patients with stage III and IV. CONCLUSION: In the case of transient bone marrow oedema, a restitutio ad integrum can be achieved with core decompression. In stage I and II of avascular necrosis, the successful outcome depends on the lesion size of the femoral head. Necrotic lesions less than 30% seem to have the best prognosis. In stage III and IV, core decompression cannot be recommended.

Adult↗

Tense and finiteness in the speech of children with specific language impairment acquiring Hebrew.

Verb morphology is often an area of extraordinary difficulty for children with specific language impairment (SLI). However, in Hebrew, this difficulty appears to be more circumscribed than in other languages. In a recent study by Dromi et al., the limitations exhibited by a group of Hebrew-speaking children with SLI were confined primarily to the use of agreement inflections within past tense. This difficulty was interpreted as being due to the fact that the agreement paradigm within past tense is rather complex (involving person, number, and gender, along with tense). This study explores another possibility--that these inflections were difficult because they required past tense in particular. Also determined was whether the children's frequent use of the morphologically simplest forms (such as past third person masculine singular) in place of the correct forms could be interpreted as their selection of a non-finite default form. A group of Hebrew-speaking children with SLI (age 4.2 to 6.1) participated, along with a group of age controls, and a group of younger normally developing children matched for mean length of utterance (MLU). The children listened to stories that were accompanied by pictures. During each story, the children completed the experimenter's incomplete sentences using appropriate verbs. To complete the sentences accurately, the children had to alter the tense or finiteness of the verb used by the experimenter in the preceding sentence. The results indicated that the children with SLI had more difficulty than both comparison groups in the production of basic present and past forms and infinitive forms of verbs that required use of one particular phonological template or 'binyan'. However, for the verbs requiring the remaining three phonological templates, the children with SLI were as capable as MLU controls in their command of past as well as present tense, and in their use of infinitive forms. It is concluded that tense and finiteness probably do not form the core of the problem faced by Hebrew-speaking children with SLI in the area of verb morphology.

Articulation Disorders↗

MR imaging of the knee: three-dimensional volume imaging combined with fast processing.

A new examination protocol for patients with suspected meniscal or hyaline cartilage disorders is presented. Knees were imaged with a fast gradient echo imaging sequence with subsequent three-dimensional transformation. Data were transferred to an image processing system that allows reconstruction in any plane desired. Approximately 200 interactively positioned reconstructions are displayed and reviewed in approximately 10 min. Thirty-five patients with suspected meniscal or hyaline cartilage disorders were examined prospectively. All underwent subsequent arthroscopy. The magnetic resonance (MR) diagnosis showed an accuracy of 91.4% compared with arthroscopic findings. Owing to the short imaging time, the proposed procedure permits screening of knee joint disorders with MR.

Arthroscopy↗

A Monte Carlo model for the absorption and flux distributions of light in tissue.

A Monte Carlo computer model has been developed to study the propagation of light in tissues. Light attenuation is assumed to result from absorption and isotropic scattering. The model has been used to predict the distribution of absorbed dose in homogeneous tissues of different absorption/scattering ratios, for illumination both by external light beams and via implanted optical fibers. The photon flux into optical fibers placed in the tissue as detectors has also been investigated. The results are interpreted in relation to the use of visible light irradiation for photo radiation therapy.

Computers↗

Cholesterol and phospholipid content of 3T3 cells and transformed derivatives.

For 3T3, PY-3T3 and SV40-3T3 cells, the contents of total lipid, cholesterol and phospholipid were determined. Weight of total lipid per cell correlates closely with cellular volume as determined microscopically. This correlation is not observed for cholesterol of phospholipid content per cell. Cholesterol content per cm2 cellular surface area is found about fifty percent higher in the transformed cell lines compared to 3T3 cells. This result is discussed in relation to thermal transitions observed in physical properties of the plasma membrane of these cells as well as in lamellar phospholipid/water model systems containing cholesterol.

Cell Line↗

Dependence of cellular surface area on growth density of 3T3 and SV40-3T3 cells.

The cell surface areas of 3T3 and SV40-3T3 cells both for suspended and for flat cells growing on the culture substrate have been determined in dependence on growth density. The surface areas of flat 3T3 and SV40-3T3 cells turn out to be independent of growth density over a wide range. For 3T3 cells the surface area of flat cells compares well with that determined by Collard and Temmink for suspended 3T3 cells taking the surface area of their coverlayer of microvilli into account. This indicates that upon suspension of flat 3T3 cells the surplus surface area is disposed of in the form of microvilli. For SV40-3T3 cells we obtained a surface area of flat cells which differs by a factor of about two from that of suspended cells as determined by Collard and Temmink including the surface area of microvilli. Microscopical diameters and electrical ("Coulter") volumina of suspended 3T3 and SV40-3T3 cells depend only little on cell density in the range investigated.

Cell Division↗

Action of brassinosteroids on the epithelial cell line from Chironomus tentans.

The two brassinosteroids, 22 S,23 S-homobrassinolide and 22 S,23 S-homocastasterone are weak competitors of the binding of [3H]ponasterone A to the intracellular ecdysteroid receptor from the epithelial cell line from Chironomus tentans. The relative affinities to the ecdysteroid receptor are 0.001 for both brassinosteroids as compared to 20-OH-ecdysone and 0.1 in comparison to ecdysone. Both substances exert morphological effects similar to those observed with 20-OH-ecdysone. Like moulting hormones both brassinosteroids inhibit chitin synthesis. However, these effects were observed only at rather high concentrations (10(-5) to 10(-4) M) which were cytotoxic for 22 S,23 S-homobrassinolide.

Acetylcholinesterase↗

Metabolic transformation of the brassinosteroid 24-epi-castasterone by the cockroach Periplaneta americana.

After feeding of 24-epi-castasterone to the cockroach Periplaneta americana an organ-specific epimerization of the brassinosteroid to 2,24-diepi-castasterone could be detected in female insects. The metabolite being observed only in the ovaries and not in the testes of the insect was identified by GC/MS in comparison with a synthesized authentic sample. Contrary, 24-epi-brassinolide is not metabolized in the sexual organs of Periplaneta americana. This is the first evidence of a metabolic transformation of a brassinosteroid in insects.

Animals↗

[New naphthalenic ligands of melatoninergic receptors].

Twenty three naphthalenic bio-isosteres of melatonin have been synthesized. The main structural variations concerned the acylamino substituents of the side chain and the alkoxy group on the 7-position of the naphthalene. Some of these compounds show greater affinity than melatonin itself for the melatonin receptor. The results of this study provide new informations on the structure affinity relationships and on the mode of interaction at the melatonin binding site.

Animals↗

Biliary atresia and meconium ileus associated with Niemann-Pick disease.

A boy, and 10 months later his sister, presented in the neonatal period with meconium ileus. Both became jaundiced and were found to have biliary atresia and Niemann-Pick disease, type C. The causes of the meconium ileus were not established. Both died before the age of 6 weeks.

Biliary Atresia↗

Fragmentation of pulmonary emboli: in vivo experimental evaluation of two high-speed rotating catheters.

PURPOSE: To test two over-the-wire systems for fragmentation of pulmonary emboli. METHODS: In 11 dogs, 22 embolic occlusions of lobar or central pulmonary arteries were performed by injection of preformed emboli through a jugular vein sheath. A commercially available device (thrombolizer) and a modified version of the impeller catheter were introduced via the femoral vein and positioned at the embolus site. RESULTS: Catheter placement at the site of the emboli was possible. In more than half of the cases a hydrophilic or an extra-stiff guidewire was necessary. The thrombolizer did not rotate properly with its original pneumatic drive and required a major modification. When sufficient rotation was provided, both fragmentation catheters were able to clear the occluded main arteries. Side branches were partly obstructed by the resulting fragments. Recanalization led to a reduction of the emboli-induced elevation of the pulmonary arterial pressure by two-thirds. Histology of the recanalized pulmonary artery segments revealed localized (impeller catheter) and widespread (thrombolizer) periarterial hemorrhage. CONCLUSION: Embolus fragmentation led to a hemodynamic improvement. The impeller catheter was less traumatic compared with the thrombolizer, which was technically insufficient.

Animals↗