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Biomedical subjects

C Gerber

Publications and source records attributed to C Gerber.

At least 37 records · Page 2Linked to original sources
PubMed1989

Regularly alternating L,D-peptides. II. The double-stranded right-handed antiparallel beta-helix in the structure of t-Boc-(L-Phe-D-Phe)4-OMe.

The crystal structure of Boc-(L-Phe-D-Phe)4-OMe has been determined by x-ray diffraction analysis. The peptide crystallizes in the triclinic system, space group P1 with a = 15.290 A, b = 15.163 A, c = 19.789 A, alpha = 102.49 degrees, beta = 96.59 degrees, gamma = 74.22 degrees, and Z = 2. The structure has been solved by coupling of the molecular replacement technique and expansion by tangent formula refinement of the set of known phases. Several cycles of Fourier calculations and least-squares refinement led to the location of 194 atoms of the two independent octapeptide chains and few molecules of cocrystallized solvent (chloroform, water, and methanol). The isotropic refinement converged to R = 0.13 for the 3077 "observed" reflections. The two independent octapeptide molecule form a dimer in the solid state: the two chains are associated by interstrand hydrogen bonds (12 of the type N-H ... O = C) with the formation of a double-stranded antiparallel right-handed -- beta 5.6-helix. These double helices can be represented as a cylinder with a hydrophilic inner core represented by the peptide units and an hydrophobic exterior constituted by the aromatic moieties. The dimensions of the cylinder are equal to those observed for Boc-(L-Val-D-Val)4-OMe. In the solid state the dimers pack with each other in an hexagonal fashion with the formation of layers; between the layers, solvent molecules fill empty spaces.

Isomerism↗
PubMed1989

[The injured and the immobilized muscle cell: ultrastructural observations].

Muscle soreness is a common feature among athletes and untrained individuals who engage in unusual, especially intense eccentric exercise. Various biochemical markers as for example elevated CK demonstrate a damage of muscle cells. The most prominent structural finding is a varying degree of disruption of the contractile material up to cell degeneration. These morphological findings reach their maximum 2 or 3 days after exercise. Signs of regeneration, however, are seen even weeks after exercise. In a prospective study we investigated the structures of the quadriceps muscle in 41 patients with chronic symptomatic instability of the anterior cruciate ligament before, 9 and 26 weeks after operation using the needle biopsy technique. The immobilized muscle showed a rapid and large atrophy which markedly reduced aerobic capacity as well as maximal strength. Preoperative values weren't attained 26 weeks postoperative despite intense physiotherapeutic exercise. The control leg showed an atrophy as well, but only aerobic capacity was reduced, maximal strength remained about the same.

Biopsy, Needle↗
PubMed1989

Muscle filament spacing and short-term heavy-resistance exercise in humans.

1. Six weeks of a dynamic heavy-resistance training of the quadriceps muscle in healthy young men resulted in a continuous increase in muscle strength, in an increase in muscle cross-sectional area (significant only in the second half of the training period) and in an increase in radiological density of the muscle tissue of 3.1% (2P less than 0.001) in the first three weeks and 1.6% (2P less than 0.01) in the second three weeks. 2. The linear distance between myosin filaments (38.7 +/- 0.3 nm before, 38.7 +/- 0.4 nm after training; mean +/- S.E.M.) as well as the ratio of actin to myosin filaments (3.94 +/- 0.03 before, 3.86 +/- 0.06 after training) did not change with training. 3. These results refute the concept that the increases in muscle strength or radiological density during short-term heavy-resistance training are caused by changes in myofilament spacing.

Adolescent↗
PubMed1989

[Sonography of the shoulder].

Sonography is a valuable method for the detection of rotator cuff tears. A high resolution transducer and an experienced examiner are necessary. The rotator cuff is not visible in large tears and has a convex outer border in small tears. Sonography reveals pathology of the subacromial bursa, joint effusions, inflammatory tissue in rheumatoid arthritis and often also bony erosions and tendon calcifications. Arthrography is still indicated in equivocal cases. Arthro-CT is the method of choice for the diagnosis of limbus and capsular pathology, but not for rotator cuff tears. MRI shows promising results in rotator cuff tears, but its role has not been definitively assessed.

Bursa, Synovial↗
PubMed1989

[Prevention of infection in elective orthopedic interventions with special reference to alloplastic joint replacement].

Based on a study of 105 patients and a comprehensive literature review we recommend a prophylactic regimen for orthopaedic procedures which is easily adaptable to the needs of individual clinics. The regimen is especially designed for joint replacements and includes basically the following four points: 1. parenteral prophylaxis with cefazolin 1 g every 6 hours for 24 hours; the first dose is given between 10 and 30 minutes before surgery (for knee-replacement the initial dose is 2 g); 2. use of bone cement impregnated with antibiotics, e.g. Palacos-Gentamycin-cement; 3. when possible the operation should be performed in a theater equipped with "ultra-clean-air" laminar air-flow and the surgeon should wear "whole-body-exhaust" suits or suits made of "Fabric 450"; 4. antibiotic selection as outlined in points one and two must be adjusted over time based on ongoing monitoring of antimicrobial resistance in the individual clinic.

Cefazolin↗
PubMed1988

The lateral supramalleolar flap.

An anatomic study (40 fresh dissected specimens) and clinical experience (14 patients) have shown the reliability of a skin flap designed on the lower third of the lateral aspect of the leg. It is supplied by a cutaneous branch from the perforating branch of the peroneal artery. This perforating branch continues distally deep to the fascia along the anterior ankle and into the foot. This can be used as a reversed pedicle, giving the flap an arc of rotation that allows coverage of the dorsal, lateral, and plantar aspects of the foot, the posterior heel, and the lower medial portion of the leg.

Adolescent↗
PubMed1988

Injuries at school. Influence of schoolmate interaction.

One quarter of all injuries in children of school age occur at school. In order to analyse the importance of schoolmate interactions and unsatisfactory schoolmate relationships for the occurrence of injuries at school a case-control study was carried out in 1986 in the comprehensive schools of Linköping. Fifty injured students and 50 controls, matched by grade and sex, were interviewed. Sixty-six percent of all injuries occurred during time not organized by the teachers. In 36% the situation was characterized by brawling or chasing. Injured students demonstrated significantly more often unsatisfactory relationships with schoolmates. In the age group at highest risk (11-13 years) differences between injured and controls were most apparent. Student proposals to prevent injuries most commonly concerned brawling during breaks. The study indicates that interaction between schoolmates and unsatisfactory schoolmate relationships are important determinants of risk of injury at school.

Adolescent↗
PubMed1988

Rotator cuff tears: correlation of sonographic and surgical findings.

High-resolution, real-time sonography of the rotator cuff was performed in 51 shoulders, and the results were correlated with findings obtained during subsequent surgery. Prospective sensitivity of sonography in detection of a tear was 100%; specificity, 75%; and accuracy, 92%. Retrospective estimation of tear size on sonograms correlated well with the intraoperative measurements for small and moderate lesions. Large lesions were often underestimated sonographically. Retrospectively, partial tears were correctly diagnosed in seven patients, and bursal thickening was recognized in 17 patients. Sonography of the shoulder proved to be an accurate, noninvasive method for the diagnosis of complete rotator cuff tears. It is useful for estimating tear size and location and may be useful in recognizing partial tears.

Adult↗
PubMed1988

The Trillat procedure for recurrent anterior instability of the shoulder.

In the Trillat procedure for recurrent anterior instability of the shoulder the coracoid process is osteotomised and tilted downward to act as a bone block, and a screw is used to fix it and the Bankart lesion to the anterior scapular neck. We reviewed 52 cases after a mean follow-up of 69 months. Results in 73% of shoulders were excellent, 10% were good, 7% fair and 10% poor. Dislocation recurred in 4%, but a positive apprehension sign was present in 10 other shoulders. Some degenerative changes were seen in 62% of shoulders, a complication known to be associated with bone-block procedures. The most important reason for loss of lateral rotation was iatrogenic impingement of the coracoid. This frequent and potentially serious complication can also cause posterior subluxation of the humeral head and osteoarthritis.

Adolescent↗
PubMed1988

[Surgical treatment concepts in soft tissue tumors of the locomotor system].

Soft tissue tumors of the extremities require a definitive histopathological diagnosis and adequate treatment unless they are known to have been present for years without any clinical change. For lesions with a straightforward clinical diagnosis (ganglion of the wrist) and for superficial tumors smaller than 3 cm, excisional biopsy is adequate. For all other lesions an open incisional biopsy should be performed. If the lesion is potentially malignant, all the appropriate staging studies must be performed before biopsy; if the tumor has been biopsied without prior staging and unexpectedly reveals a malignant lesion, complete staging must be performed before definitive surgery is undertaken. Soft tissue sarcomas extend rapidly within the tissue of the compartment they originated in, but tend to respect compartmental boundaries. Radical resection of the entire compartment containing the sarcoma is thus the surgical treatment of choice. Adjuvant radio- and/or chemotherapy are necessary in the majority of these cases and should be integrated into the treatment strategy.

Biopsy↗
PubMed1988

[Critical study of the repair of the anterior cruciate ligament of the knee using a pediculated flap to the Hoffa pad taken from the middle 3d of the patellar tendon. 50 surgical knees with a 2-to-4-year follow-up].

A reconstruction of the anterior cruciate ligament of the knee has been devised on the anatomical principle of an intra-articular flap taken from the middle third of the patellar tendon and based on the sub-patellar fat pad. Fifty knees have been treated and assessed after a follow-up of two to four years to provide a critical analysis of the method. The technique of the operation is described in detail in relation to the isometric reconstruction of the course of the anterior cruciate ligament. With a mean follow-up of 33 months (minimum 24 and maximum 48 months), 98 per cent of the patients had a good result as regards stability together with a good anatomical result, with complete or almost complete elimination of the anterior drawer sign and the jerk test in 96 per cent. The subjective result described by the patient was good in 92 per cent but only 54 per cent returned to the same sporting activity. The main problem encountered with this method was loss of 10 degrees of extension in 40 per cent of patients and loss of more than 10 degrees in 22 per cent. This loss of extension arose on the one hand from an impingement of the fatty pedicle in a narrow intercondylar notch and on the other from an associated postero-lateral laxity which resulted in an intra-articular transplant which was too short despite its anatomical attachments. The pedicled transplant has not given better results than free transplants and has given rise to additional iatrogenic problems even with a meticulous operative technique.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1988

Latissimus dorsi transfer for the treatment of massive tears of the rotator cuff. A preliminary report.

Symptomatic irrepairable rotator cuff tears usually entail complete loss of the substance of the supraspinatus and infraspinatus tendons. Loss of external rotation control and cranial migration of the humeral head on attempted flexion or abduction of the shoulder are the functional hallmarks. Transfer of the latissimus dorsi tendon from the humeral shaft to the superolateral humeral head provides a large, vascularized tendon that can be used to close a massive cuff defect and that exerts an external rotation and head-depressing moment that allow more effective action of the deltoid muscle. This procedure was carried out in 14 patients without any significant complications. Pain relief and functional results in those four cases with a minimum follow-up period of one year (average, 14 months) compared favorably with alternative treatment methods and warrant further anatomic, electromyographic, and clinical investigation.

Adult↗
PubMed1987

Images of a lipid bilayer at molecular resolution by scanning tunneling microscopy.

The molecular structure of a fatty acid bilayer has been recorded with a scanning tunneling microscope operating in air. The molecular film, a bilayer of cadmium icosanoate (arachidate), was deposited onto a graphite substrate by the Langmuir-Blodgett technique. The packing of the lipid film was found to be partially ordered. Along one axis of the triclinic unit cell the intermolecular distance varied randomly around a mean of 5.84 A with a SD of 0.24 A. Along the other axis the mean distance was 4.1 A and appeared to vary monotonically over several intermolecular distances, indicating that a superstructure of longer range may exist. The molecular density was one molecular per 19.4 A2. The surprising ability of the scanning tunneling microscope to image the individual molecular chains demonstrates that electrons from the graphite can be transferred along the molecular chains for a distance of 50 A.

Arachidonic Acid↗
PubMed1987

[Diaphyseal resection and reconstruction in cases of tumors involving the long bones of the extremities. Apropos of 23 cases].

An analysis has been made of the records of 23 cases of resection-reconstruction of the shafts of long bones for a variety of tumours of bone. Four were in the humerus, four in the forearm bones, five in the femur and ten in the tibia. The reconstructed bone was stabilised by an intramedullary nail in thirteen cases and by a plate or blade-plate in five cases. In five cases, the grafts were simply held by screws. The bone was reconstructed by an autograft in thirteen cases and by allograft in ten cases, four of which were combined with an autograft. Resections in the upper limb gave rise to few complications. Conversely, reconstructions in the lower limbs, particularly of the tibia, were associated with a significant number of complications because of infection and delayed union. The best fixation, when it was technically possible, was an intramedullary nail surrounded by autografts. Allografts, and the vascularised fibular graft, were very liable to secondary fatigue fracture. A combination of autograft and allograft needs to be considered if a sufficient quantity of autograft is not available.

Bone Neoplasms↗