Biomedical subjects

P Engelhardt

Publications and source records attributed to P Engelhardt.

At least 37 records · Page 2Linked to original sources

PubMed1996

Phenethylthiazolylthiourea (PETT) compounds as a new class of HIV-1 reverse transcriptase inhibitors. 2. Synthesis and further structure-activity relationship studies of PETT analogs.

Phenylethylthiazolylthiourea (PETT) derivatives have been identified as a new series of non-nucleoside inhibitors of HIV-1 RT. Structure-activity relationship studies of this class of compounds resulted in the identification of N-[2-(2-pyridyl)ethyl]-N'-[2-(5-bromopyridyl)]-thiourea hydrochloride (trovirdine; LY300046.HCl) as a highly potent anti-HIV-1 agent. Trovirdine is currently in phase one clinical trials for potential use in the treatment of AIDS. Extension of these structure-activity relationship studies to identify additional compounds in this series with improved properties is ongoing. A part of this work is described here. Replacement of the two aromatic moieties of the PETT compounds by various substituted or unsubstituted heteroaromatic rings was investigated. In addition, the effects of multiple substitution in the phenyl ring were also studied. The antiviral activities were determined on wild-type and constructed mutants of HIV-1 RT and on wild-type HIV-1 and mutant viruses derived thereof, Ile100 and Cys181, in cell culture assays. Some selected compounds were determined on double-mutant viruses, HIV-1 (Ile 100/Asn103) and HIV-1 (Ile100/Cys181). A number of highly potent analogs were synthesized. These compounds displayed IC50's against wild-type RT between 0.6 and 5 nM. In cell culture, these agents inhibited wild-type HIV-1 with ED50's between 1 and 5 nM in MT-4 cells. In addition, these derivatives inhibited mutant HIV-1 RT (Ile 100) with IC50's between 20 and 50 nM and mutant HIV-1 RT (Cys 181) with IC50's between 4 and 10 nM, and in cell culture they inhibited mutant HIV-1 (Ile100) with ED50's between 9 and 100 nM and mutant HIV-1 (Cys181) with ED50's between 3 and 20 nM.

Animals↗

PubMed1996

[Percutaneous iliosacral screw fixation of vertical unstable pelvic ring fractures].

In type C pelvic ring fractures ORIF is the treatment of choice. Early definitive fixation often is not possible due to severe soft tissue injuries and hemorrhage. The percutaneous iliosacral screw fixation with the patient supine offers a minimally invasive and definitive fixation method of the posterior unstable pelvic ring also in acute situations. Our first experience shows that a ventral stabilisation is necessary in combination with one dorsal screw. Both fixations are managed in the supine position of the patient during one anesthesia.

Adult↗

PubMed1995

[Long-term results in pediatric orthopedics].

Whether to treat deformities in childhood or even to operate on them is a difficult decision which may affect a patient's whole life. Most important is a sound knowledge of the natural course. Many 'deformities' are just normal variants, and others improve during the growth period, but some get worse and may cause damage in later life. However the outcome of operations is not always certain. Recurrence may occur as well as overcorrection; therefore, the long-term prognosis, with or without treatment, must be the guideline for indications. If an operation is considered, timing and extent of a correction are decisive. On the grounds of long-term outcome studies, guidelines can be established for the treatment of different diseases and deformities: upper extremities [dysmelia, elbow], spine [scoliosis, Scheuermann's disease, spondylolisthesis], hip (congenital dysplasia, Perthes' disease, slipped epiphysis), knee and feet (flatfoot, pes equinovarus).

Adolescent↗

PubMed1994

[Prognosis of spongiosa-plasty of the fractured tibial shaft].

Records of 97 patients who had undergone a total of 171 cancellous bone grafting procedures from 1971 to 1988 were analysed with respect to promotion of bony healing. It was found that 50 patients had undergone 1 grafting procedure each in the tibia, while 47 patients had each undergone 2-5 bone grafting procedures. Therefore only every second procedure at best could be considered as successful. Predictors for unsuccessful grafting were found to be large bone defects, poor vascularization and, especially, infection. Primary grafting was related to more problems in terms of uneventful bone healing than was "postprimary" grafting after 3 and more weeks after accident. We therefore recommend delayed grafting in cases of fractures with soft tissue ruptures. In all cases of segmental bone loss multiple bone grafting procedures should now be carefully compared with the advantages of segmental bone transport techniques.

Adolescent↗

PubMed1994

[Natural course of epiphysiolysis of the femur head].

The natural course of slipped capital femoral epiphysis (SCFE) is biphasic. During the active course there is a slow progression of the epiphyseal tilt. A certain remodeling potential around the head neck junction can be observed, the goal of which is self-limitation of the dislocation process. Closure of the epiphyseal plate terminates the first phase. The resulting deformity is called prearthrosis. Long-term research is being devoted to determining whether coxarthrosis is going to develop in the further course of the disease and, if so, when. In agreement with many researchers, this author found that the natural history of the malunited dislocation is mild deterioration related to the severity of the angle of slippage. Chondrolysis during the active slippage process is responsible for the high incidence of coxarthrosis. AVN of the capital epiphysis can seldom be observed in non-treated hips.

Adolescent↗

PubMed1993

[Palliative orthopedic therapy in tumor-induced osteopathies].

Skeletal instabilities due to neoplastic diseases in the aged are most often of metastatic nature. Pathologic fractures are observed most frequently with breast-, lung- and prostatic primaries. Palliative orthopedic surgery by stabilisation of a pathologic fracture (osteosynthesis, endoprosthesis) or by decompression and spondylodesis of vertebral manifestations alleviate pain considerably. The mean survival time of patients mobilized after such surgery is approximately 9 months.

Aged↗

PubMed1993

[Resection arthrodesis of the proximal ankle joint in Ewing's sarcoma. Maintenance of leg length using distraction osteogenesis].

The technique of segmental transport of the tibia according to Ilzarov is a well-known procedure in pediatric orthopedics, but in the treatment of bone tumors it has not yet been established. The method is also applicable for filling a large gap after tumor resection in the distal tibia. A case history is presented in which Ewing's sarcoma localized in the distal tibia was removed surgically after multiagent chemotherapy. The ankle joint was successfully fused after bone transport of the tibia 5 cm distal to the talus.

Adult↗

PubMed1992

[Malgaigne pelvic ring injury in childhood].

Pelvic girdle injuries leading to anterior and posterior disruption are rarely seen in children. External fixation is useful to reduce and stabilize the pelvis in order to control massive blood loss due to severe venous bleeding. The anterior tension band element of the external fixator can successfully maintain reduction of the pelvic girdle. Dislocation or fracture dislocation of the sacroiliacal joint cannot be reduced with simple traction techniques. Leg length discrepancy is to be expected when the hemipelvis is displaced. Seven cases of this rare injury in children are presented together with the late outcome. Treatment modalities are discussed.

Adolescent↗

PubMed1991

[Modified dynamic hip screw implant in pathologic fracture of the femoral neck (juvenile bone cyst)].

Pathological fractures of the neck of the femur during adolescence should be treated in order to maintain the original length of the femoral neck. The available implants are designed as sliding nail plates and therefore are not capable of blocking collapse of the neck in the presence of a cystic lesion. By loading the unthreaded part of the Dynamic Hip Screw by segments of tubes the gliding mechanism is locked. The hip screw modified in this way can secure anatomic healing of the femoral neck.

Adolescent↗

PubMed1991

[Possibilities for treating chronic radius head dislocations].

Thirteen patients with neglected luxation of the proximal radius who were treated with different surgical procedures at the Orthopaedic Department of the Kantonsspital in St. Gallen (Switzerland) returned for evaluation at an average of 7 years postoperatively. The luxation was traumatic in 11 cases (7 Monteggia-fractures) and in 2 cases due to a dysplasia of the forearm. In 7 patients the deformity recurred and in 1 a synostosis between radius and ulna was noticed. In 4 cases the wrist showed a relative overlength of the ulna. Proximal osteotomy of the ulna in combination with open reduction of the proximal radius gave better results than the other procedures. Congenital luxation of the proximal radius does not cause much symptoms but surgical treatment often results in recurrence of the deformity. Therefore, we only occasionally advocate operative therapy in these cases.

Adolescent↗

PubMed1990

[Femoral shaft fractures in childhood. 25-year experience using Weber's table].

25 years ago a new type of skeleton traction was introduced by B.G. Weber (Webertisch), allowing easy control and reduction in all planes of the fragments of femoral shaft fractures in children. Since 1961 329 shaft fractures were treated at our hospital; 215 by the Webertisch method, 33 with other types of traction and 81 needed to be operated on. From 1961 through 1973 the number of Webertisch treatments was higher than in the period from 1974-1987 (182 resp. 147); but in the second period there were more children with complex and severe injuries and more children older than 10 years needed to be operated on. The method proved to be save and easy to handle and no modifications took place.

Adolescent↗

PubMed1988

[Hip endoprostheses in Paget's disease].

When the region around the hip joint is affected by Paget's disease it takes up to 10 years for degenerative joint disease requiring treatment to develop. Medium-term follow-up examination of 27 hip replacements in patients with Paget's disease revealed generally good results, though the rate of loosening, with 30%, was clearly elevated compared with that observed in a control group of patients not suffering from Paget's disease. The reduced bone stability and the increased bleeding tendency can cause complications even during the operation when Paget's disease is present. Since most of the patients affected are elderly prosthetic hip joint replacement is practically always indicated.

Adult↗

PubMed1988

[The significance of the center-edge angle in the prognosis of the dislocated hip 50 years after its initial description by Wiberg].

In a small child, the prognosis of hip dysplasia is determined most of all by the quality of the covering over the femoral head. A simple radiometric expression of the extent repositioning has been achieved is Wiberg's CE angle (1939). It is suggested that a new classification be established for the critical area: between 10 degrees and 20 degrees. Other criteria for evaluating dysplasia of the hip are suitable for establishing the prognosis--assuming they include the socket; however, their application is often more complicated. Deformation of the femoral head, the CCD angle, and antetorsion of the femoral head are less suitable predictors. In the 100 patients with uni- or bilateral CDH, the long-term follow-up (mean of 47 years), indicates that there is an extraordinarily high incidence of arthrosis.

Adolescent↗

PubMed1988

[Intra-articular fractures of the elbow in childhood].

Correct assessment of the prognosis is a special problem in intra-articular fractures of the elbow in children. Pseudarthrosis, which is other-wise not seen in children, is often observed in fractures of the radial condyle but, together with other post-traumatic dislocations (fishtail deformity), is of little functional significance. In principle, an operation should be performed even on slightly dislocated fragments at the distal humeral joint surface. Intra-articular fractures of the proximal ulna also tend to result in persistent dislocations and therefore require exact repositioning. Fractures of the head of the radius can usually be expected to reduce spontaneously with astonishingly good results and only seldom require open repositioning. Growth disturbances can occur many years after the original injury - even if the treatment is correct.

Child↗

PubMed1984