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Biomedical subjects

A Karev

Publications and source records attributed to A Karev.

At least 19 recordsLinked to original sources

Omega- and Omega+ production in central Pb + Pb collisions at 40 and 158A GeV.

Results are presented on Omega production in central Pb+Pb collisions at 40 and 158A GeV beam energy. For the first time in heavy ion reactions, rapidity distributions and total yields were measured for the sum Omega(-) + Omega(+) at 40A GeV and for Omega(-) and Omega(+) separately at 158A GeV. The yields are strongly underpredicted by the string-hadronic UrQMD model but agree better with predictions from hadron gas models.

Journal Article↗

System-size dependence of strangeness production in nucleus-nucleus collisions at squareroot[sNN]=17.3 GeV.

Emission of pi+/-, K+/-, phi, and Lambda was measured in near-central C+C and Si+Si collisions at 158 AGeV beam energy. Together with earlier data for p+p, S+S, and Pb+Pb, the system-size dependence of relative strangeness production in nucleus-nucleus collisions is obtained. Its fast rise and the saturation observed at about 60 participating nucleons can be understood as the onset of the formation of coherent systems of increasing size.

Journal Article↗

Lambda and lambda production in central Pb-Pb collisions at 40, 80, and 158A GeV.

Production of Lambda and Antilambda hyperons was measured in central Pb-Pb collisions at 40, 80, and 158A GeV beam energy on a fixed target. Transverse mass spectra and rapidity distributions are given for all three energies. The Lambda/pi ratio at midrapidity and in full phase space shows a pronounced maximum between the highest BNL Alternating Gradient Synchrotron and 40A GeV CERN Super Proton Synchrotron energies, whereas the Lambda/pi ratio exhibits a monotonic increase.

Journal Article↗

Evidence for an exotic S= -2, Q= -2 baryon resonance in proton-proton collisions at the CERN SPS.

Results of resonance searches in the Xi(-)pi(-), Xi(-)pi(+), Xi;(+)pi(-), and Xi;(+)pi(+) invariant mass spectra in proton-proton collisions at sqrt[s]=17.2 GeV are presented. Evidence is shown for the existence of a narrow Xi(-)pi(-) baryon resonance with mass of 1.862+/-0.002 GeV/c(2) and width below the detector resolution of about 0.018 GeV/c(2). The significance is estimated to be above 4.2sigma. This state is a candidate for the hypothetical exotic Xi(--)(3/2) baryon with S=-2, I=3 / 2, and a quark content of (dsdsū). At the same mass, a peak is observed in the Xi(-)pi(+) spectrum which is a candidate for the Xi(0)(3/2) member of this isospin quartet with a quark content of (dsus[-]d). The corresponding antibaryon spectra also show enhancements at the same invariant mass.

Journal Article↗

The mechanical efficiency of the pulley system in normal digits compared with a reconstructed system using the "belt loop" technique.

A specially designed tensiometer was employed to compare the mechanical efficiency of normal and reconstructed pulley systems in the thumb and the fingers. The "belt loop" technique for reconstruction was used in five fresh cadavers. A total of 10 thumbs and 40 fingers were dissected, and after a measured pull on the proximal tendon the yielded power output at the tip was compared with the normal and reconstructed systems. A mean of 10% loss of power in the reconstructed system in the thumb and 40% of power in the fingers, with excellent range of motion and no bow stringing was recorded.

Aged↗

Dupuytren's contracture studied with monoclonal antibodies to connective tissue differentiation antigens.

Seventeen patients with Dupuytren's contracture underwent partial fasciectomy, and frozen tissue sections from the involved palmar fascia were prepared for binding studies with hybridoma-derived murine monoclonal antibodies (MoAb) recognizing connective tissue differentiation antigens. The two MoAb used were both generated using human sarcomas as immunizing agents, 23H7 known to bind to an antigen shared by selected sarcomas and carcinomas but not normal adult tissues except a subset of granulocytes, and 12C9 shown to recognize a common fibroblastic marker. MoAb 23H7 was discovered to bind to a subset of fibroblasts within the lesions of six of 17 patients with Dupuytren's disease. Occasionally it immunostained a single cell population associated with tissue granulocytes dispersed in the surroundings of the lesions. MoAb 12C9 was found to be expressed in only 12 of 17 specimens prepared from involved lesions from Dupuytren's disease. It is suggested that fibroblasts from selected patients with Dupuytren's contracture express a novel antigen, defined by MoAb 23H7, previously shown to be associated with human sarcomas and other neoplasia. The other fibroblast marker which is defined by MoAb 12C9 and known to be a common connective tissue antigen, is only occasionally expressed in lesions involved with this disease. Though additional markers associated with Dupuytren's contracture remain to be defined, the MoAb, capable of defining connective tissue differentiation markers, reported in this study may serve as new immunological probes for immunodissecting this syndrome into subsets of diseases which may better define the variety of clinical patterns presented by patients.

Adult↗

Trapezius transfer for paralysis of the deltoid.

A case of selective paralysis of shoulder muscles with its reconstructive procedure, is presented. The deltoid, infra- and supraspinatus paralysed, leaving one of the steering group of muscles around the shoulder--the subscapularis--intact, made the transfer of the trapezius to deltoid feasible, utilizing a modification of Saha's technique. An excellent result with full range of motion of the paralysed shoulder has been achieved.

Adult↗

Anatomic observations of the carpal tunnel in cadavers with a report of unusual thickening of the perineurium of the median nerve.

The carpal tunnel of 50 cadavers (100 hands) was dissected. Macroscopic finding included 14 median nerves with pressure signs (in 4 cadavers, unilaterally and 5 bilaterally). In three cadavers, marked synovitis was seen around the tendons and the nerve; in one, lipoma was evident; and in the rest, thickening of the volar carpal ligament was seen. Microscopic examination of the compressed nerves showed concentric thickening of the perineurium, thrombosis of veins, and intrafascicular fibrosis. In one nerve, the thickening of the perineurium was not concentric, but only at that part of the fascicle adjacent to the volar carpal ligament in an "onion peel" form.

Adult↗