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Biomedical subjects

C Kusnick

Publications and source records attributed to C Kusnick.

6 recordsLinked to original sources

The usefulness of a biosensor controlled perfusion cell culture for the investigation of new drugs demonstrated with the marine fungus Kirschsteiniothelia maritima.

The investigation of new biological active substances from limited sources for example from marine organisms needs sensitive and evident test systems. Such a system is the glucose biosensor controlled perfusion cell culture. The glucose consumption of cells is a very sensitive parameter which allows the continuous measurement of external effects of test substances on the cells under in vivo-like conditions. Cytotoxic concentrations of active substances as well as a virus infection lowers the glucose consumption of continuously perfused cells. This effect can be monitored using a glucose biosensor. The influence of drugs and the virus infection can be observed simultaneously in the same system continuously over several days. With two substances isolated from the marine fungus Kirschsteiniothelia maritima investigations for cytotoxic and for antiviral effects are demonstrated.

Anti-Bacterial Agents↗

Screening of Yemeni medicinal plants for antibacterial and cytotoxic activities.

Ethanolic extracts of 20 selected plant species used by Yemeni traditional healers to treat infectious diseases were screened for their antibacterial activity against both Gram-positive and Gram-negative bacteria, as well as for cytotoxic activity. Fourteen of the ethanolic extracts showed variable degrees of antibacterial activity. The active ethanolic extracts were partitioned between ethyl acetate and water for a first separation. The ethyl acetate extract of Lawsonia inermis was found to be the most active one against all bacteria in the test system. Other promising results could be obtained from extracts of Aloe perryi, Indigofera oblongifolia, Meriandra benghalensis and Ziziphus spina christi. Additionally, the ethanolic extracts of the 20 plants under investigation were tested for their cytotoxic effects on FL-cells using the neutral red assay. Extracts of Calotropis procera, Chenopodium murale, Pulicaria orientalis, Tribulus terrestris and Withania somniferum displayed a remarkable activity.

Anti-Bacterial Agents↗

Radiographic evaluation of joints resurfaced with osteochondral shell allografts.

The radiographic features of 41 cadaveric osteochondral shell (low ratio of subchondral bone to articular cartilage) allografts placed in 24 patients for articular resurfacing as an alternative to arthroplasty are presented. Underlying causes of joint disease included ischemic necrosis (20 grafts), osteochondritis dissecans (nine), chondromalacia patellae (10), and posttraumatic osteochondral fracture with degenerative disease (two). Congruity with the adjacent native articular surface and the opposite side of the joint was evident on immediate postoperative radiographs in all patients, and proved to be critical to the ultimate success of the procedure. On follow-up radiographs over a period of 2-28 months, successful incorporation of the allograft was characterized by progressive loss of the relative increased density of the graft, in association with diminished lucency related to new bone formation at the graft-native bone interface, as well as maintained alignment. Graft failure was associated with positional changes including collapse, persistent increased density, and poorly defined fragmentation that occasionally simulated infection radiographically and resulted in intraarticular bodies. Resurfacing of diseased articulations with osteochondral shell allografts constitutes a potentially desirable alternative to total joint arthroplasty, particularly among younger patients. Consequently, an awareness of the expected radiographic alterations associated with graft incorporation and failure is important.

Adolescent↗

New concepts in bone grafting.

The authors review the diagnostic and surgical imaging aspects of a number of recent bone grafting procedures in the orthopaedic management of various osseous and articular disorders. They discuss several innovative new approaches to bone grafting as well as the use of a variety of bone grafting substitute materials. They discuss the three types of bone graft available for orthopaedic reconstruction; autograft, allograft or homograft and xenograft or heterograft. They stress that an awareness of the radiographic features of each of the various bone grafting techniques is important to the physician dealing with musculoskeletal disorders in determining the results of his efforts.

Bone Transplantation↗

Studies of Doppler aortic flow velocity during supine bicycle exercise.

Although Doppler echocardiography is useful in the assessment of left ventricular function at rest, little information is available on the application of this technique during exercise. Consequently, Doppler aortic flow studies were performed in 17 young normal subjects during and after supine bicycle exercise. The purposes of the study were to determine the feasibility of recording Doppler aortic flow velocity with a suprasternal notch transducer during exercise and to assess the changes in normal aortic flow velocity parameters during exercise and early recovery. Each subject exercised until fatigue; mean duration of exercise was 10 minutes. Heart rate increased from a mean of 69 beats/min at control to 159 beats/min at peak exercise. On average, aortic peak flow velocity increased by 45% from control, reaching its maximum at 2 minutes after exercise. Ejection time decreased by 34% during exercise, being shortest at peak exercise. Heart rate, peak flow velocity and ejection time had not returned to normal by 10 minutes after exercise. Aortic flow velocity integral (a relative measure of stroke volume) decreased by 10% at peak exercise (p less than 0.05) compared with control, but had returned to control at 2 minutes after exercise. Despite mild aliasing, increased spectral dispersion, faster heart rates and increased respiratory rate during maximal exercise, aortic flow velocity measurements could be recorded using the suprasternal technique. These baseline Doppler exercise data should be useful in further studies of exercise hemodynamic changes in patients with heart disease.

Adolescent↗