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Biomedical subjects

G Herr

Publications and source records attributed to G Herr.

14 recordsLinked to original sources
PubMed1994

Bone substitute with osteoinductive biomaterials--current and future clinical applications.

In craniomaxillofacial surgery, possible indications for the use of osteo-inductive biomaterials are interposition in intraosseous defects, contour augmentation, and reconstruction of segmental defects. The experimental results in the field of bone morphogenetic protein (BMP) research within the last few years have shown that it is possible to combine osteoinductive proteins with suitable carrier materials to obtain new composite osteoinductive biomaterials. These carrier materials function as slow-delivery systems for BMP. By combination of BMP with different carrier materials such as various types of calcium phosphate ceramics, collagen or inactive collagenous bone matrix, and other organic and inorganic carriers, the biomaterial can be adapted to clinical demands in a wide range. In several experimental animal studies, we investigated nine different calcium phosphate ceramics and inactive rat bone matrix for their use as BMP carrier. All materials tested seem to be suitable carriers for BMP. The first clinical applications are discussed.

Animals↗
PubMed1993

Osteogenic activity of bone morphogenetic protein and hydroxyapatite composite implants.

In an experimental study in rats hydroxyapatite (HA) ceramics of characteristics and inactive rat bone matrix were investigated comparatively for their suitability as carriers for osteoinductive factors. Bone morphogenetic protein was extracted from long bones of pigs under dissociative conditions and partially purified by gel filtration. The resulting pBMP was combined with the granular hydroxyapatite ceramics Osprovit, Algipore, Frialit and inactive rat bone matrix (IBM) by precipitation of aliquots of this pBMP fraction onto pellets of each carrier material. The osteogenic activity of these composite implants and of corresponding controls was bioassayed by implantation into muscle pouches of immunodeficient rats. All pBMP-HA ceramic implants elicited ectopic bone formation within 25 days after implantation, whereas control implants did not show any osteoinductive ability. Alkaline phosphatase (AP) activity of the explant tissues was determined for quantitation of bone formation. Due to the high incidence of bone formation found in each pBMP group all HA ceramics tested seem to be basically suitable as carriers for osteoinductive factors. Algipore, a highly porous phycogen HA ceramic, was found to be quantitatively superior to all other materials investigated due to its very large surface available for protein binding.

Animals↗
PubMed1991

Bone morphogenetic protein: a review.

The osteogenic potential of bone and bone matrix has been characterised only by its biological effects and the parameters influencing it. Recently, the osteoinductive ability of bone matrix had been defined chemically by the description of a bone morphogenetic protein (BMP), and the parameters of osteogenic factors from different species have now been recognised. The current state of isolation, purification and characterisation of these factors is summarised in this review. General aspects of the isolation and testing of BMP preparations, and the results of orthotopic application of BMP implants, including clinical cases, are reported.

Animals↗
PubMed1984

Anaesthesia for caesarean section and cerebral aneurysm clipping.

A pregnant patient at 38 weeks gestation presented for a combined procedure of Caesarean section, tubal ligation and cerebral aneurysm clipping. Anaesthesia was induced with thiopental, succinylcholine was administered to facilitate tracheal intubation, and intravenous lidocaine and sodium nitroprusside were used to reduce the hypertensive response to tracheal intubation. Anaesthesia was maintained with nitrous oxide until delivery of the infant, after which time fentanyl, low-dose halothane and pancuronium were added for maintenance of anaesthesia during the neurosurgical procedure. Blood pressure was controlled during the case by administration of a sodium nitroprusside infusion and propranolol. Following completion of the surgical procedures, the patient promptly emerged from anaesthesia and was neurologically normal in the operating room. It is concluded that general anaesthesia can be used satisfactorily for a combined procedure of Caesarean section and cerebral aneurysm clipping.

Adult↗
PubMed1984

Objective evaluation of clinical performance and correlation with knowledge.

In certifying competence of anesthesiologists who have finished residency training, knowledge and judgment are evaluated objectively using written and oral examinations. Clinical motor skills, however, are not routinely assessed by objective techniques. This implicitly assumes that knowledge and judgment correlate with performance of motor skills. This study was designed to evaluate whether performance of a particular motor skill correlates with performance on a knowledge test related to that skill. To do this, we developed a criterion-referenced Spinal Anesthesia Skill Test and a knowledge test using multiple-choice questions related to spinal anesthesia. Both the skill and knowledge tests were administered to 44 residents at various levels of training at five major anesthesia teaching programs. Scores on the skill test were significantly higher than in the knowledge test, suggesting that proficiency in this essential motor skill is achieved earlier in training. There was no correlation between scores on the skill test and knowledge test. There were institution-linked differences in the scores on the skill test, suggesting that teaching of motor skills is not uniform. The advantages of developing criteria of performance of motor skills is discussed.

Anesthesia, Spinal↗
PubMed1981

Performance evaluation: continuous lumbar epidural anesthesia skill test.

The evaluation of skills in anesthesiology residents is usually subjective and lacks demonstrable reliability. Therefore, an objective criterion-referenced skill test for measuring performance of continuous lumbar epidural anesthesia was developed. For such a test to be useful, it is necessary to demonstrate agreement among rater-observers. Eight performances of continuous lumbar epidural anesthesia were recorded on video tape and simultaneously rated by nine anesthesiology faculty observers to determine inter-rater reliability. Inter-rater agreement was analyzed by determining coefficient kappa for each item and the entire test. Coefficient kappa for the entire test was 0.82 indicating a high degree of agreement between raters on the performance or nonperformance of various items. Development and utility of skill tests are discussed.

Anesthesia, Epidural↗
PubMed1978

Droperidol, fentanyl and morphine for i.v. surgical premedication.

Fentanyl 0.1 mg and morphine 10 mg alone and in combination with droperidol 2.5 and 5.0 mg were studied for i.v. surgical premedication in 240 patients. Relief of anxiety, sedation, lack of recall, patient acceptance and side-effects were evaluated. The addition of droperidol to fentanyl and morphine produced greater sedation and relief of anxiety before operation, but did not improve patient acceptance or lack of recall.

Adolescent↗