Biomedical subjects

A Katzer

Publications and source records attributed to A Katzer.

27 records · Page 2Linked to original sources

PubMed1996

[Experiences with the classic nail in management of per-/subtrochanteric femoral fractures in elderly patients].

In the department of trauma and reconstructive surgery at the University Hospital of Hamburg-Eppendorf (UKE) the surgical treatment of unstable per- and subtrochanteric femoral fractures (AO 31A2 and 31A3) in elderly patients with severe osteoporosis includes the implantation of dynamic hip screws (DHS) and gamma nails, as well as the straighter "classic nails". Using 43 short and 15 long classic nails, 58 fractures in seven women and 51 men, respectively, with an average age of 85 years (65-98 years) were stabilized over the last 2 years with good results (98.3% primary full weight bearing). In order to facilitate implantation of the longer nails, additional antetorsion of the femoral neck screw and improvement of the distal interlocking have been developed by the manufacturer.

Aged↗

PubMed1995

Mapping of a human rRNA gene in the YAC contig surrounding the SMA candidate gene.

Using the yeast artificial chromosome (YAC) 116 flanking the autosomal recessive spinal muscular atrophy (SMA) gene region, we have screened a human fetal brain cDNA library and isolated the cDNA clone 14-3/9 with an insert size of 2.5 kb. The cDNA clone could be identified as part of the human rRNA gene coding for 28S rRNA with a total size of 5025 bp. The human 28S rRNA is involved in the organization of the 60S ribosomal subparticle and is arranged in a 13-kb pre-rRNA transcription unit that occurs in tandem repeat clusters. Multiple copies of the rRNA gene have been mapped by pulsed field blot hybridization in the YAC contig between YAC 66 and YAC 116, which encompasses the SMA candidate gene, and additionally in the distally localized YAC 153.

Adult↗

PubMed1995

[Experiences with plate osteosynthesis in treatment of peri- and sub-prosthetic femoral fractures].

Plate-osteosynthesis proves to be an established procedure in our department for treatment of fractures of the femur in patients older than 70 years with total hip replacement even when loosened. It offers the advantages of comparably low aggressive standard operation techniques and acceptable success rates. This treatment allows for short preoperative period of the patients with their typical multimorbidity in many traumatological departments. In younger patients with symptomatical loosening, simultaneous exchange of the hip prosthesis should always be considered. Thus, individual therapy concept including the specific fracture type, general condition and age must be followed for each patient.

Aged↗

PubMed1995

Cytotoxicity and mutagenicity of Kevlar: an in vitro evaluation.

Toxicity and mutagenicity of Kevlar 49 (PPPT; poly-para-phenylene-terephthalamide) was tested in six strains of Salmonella typhimurium (Ames test; TA97, TA98, TA100, TA102, TA1535, TA1537) with and without an external metabolic activation system (S9), as well as in a mammalian cell mutagenesis assay using V79 Chinese hamster cells. For the Ames test, liquid preincubation, which is considered particularly sensitive, was used. The cells were incubated for 24 h at a temperature of 37 degrees C either directly with Kevlar49 or with ethanol- or chloroform-extracted Kevlar49. The experiments were performed at least twice. The Ames test with six different Salmonella typhimurium strains featuring either base pair substitution or frameshift mutations revealed no cytotoxic or mutagenic activity of Kevlar49. In the mammalian cell mutagenesis assay, using 8-azaguanine (AG) as a selective agent, Kevlar49 was also devoid of cytotoxic or mutagenic activity. Both tests have to be regarded as an initial exploratory screening due to the chosen testing conditions and should be supplemented by tests at different temperatures.

Animals↗

PubMed1994

Fine mapping of human PI 3-kinase associated p85 alpha transcripts in the YAC contig surrounding the spinal muscular atrophy gene.

During a search for transcribed sequences within the gene region for autosomal recessive spinal muscular atrophy (SMA), two cDNA clones were isolated from a human fetal brain and an adult spinal cord cDNA library, respectively, by use of the cosmid LA96B (LAS96). The clones sized 950 bp and 1733 bp detect a 7.7-kb transcript in all tested human tissues. An additional transcript of 6.6 kb is detectable in brain and kidney, and faintly in skeletal muscle and liver. Using comparative human Northern blot analysis, the isolated LA96B cDNA clones could be identified as parts of the 3' untranslated region from the phosphatidylinositol 3 (PI3)-kinase associated p85 alpha transcripts; these were unknown up to now. The 5' end of the gene was mapped to YAC-EFTA:A, whereas the 3' end was localized within the distal overlapping YAC 85 flanking the SMA candidate gene region.

Adult↗

PubMed1994

[Imaging of alloplastic ligament implant. An in vivo and in vitro study exemplified by Kevlar].

Neither native X-ray nor CT or NMR allow to evaluate intraarticular implantation results of Kevlar -49 directly. In animal trials, the course of an artificial ligament may only be presumed from connective tissue ingrowth. Although soft tissue structure appears much better in NMR than in CT, direct proof of ligament continuity is still impossible. As soon as the connective tissue becomes continuous, it appears clearly and allows indirect evaluation of the prosthesis, as integrity can be judged by its shape like in natural cruciate ligament. Anatomic preparations show that connective tissue fills up the small space between the two cords of a Kevlar -49 two bundle prosthesis eight weeks after implantation, so that imaging systems show only one intraarticular bundle.

Animals↗

PubMed1994

[Whiplash injury of the cervical spine--on the role of pre-existing degenerative diseases].

Radiological investigations contribute little in differentiating the problems of patients with whiplash injuries. Nevertheless the more prolonged cases of whiplash injuries must not be attributed to preexisting degenerative disease, despite radiologically-proven medicolegal opinion. In this study, 60 patients who were seen for whiplash injuries in the Department for Trauma and Reconstructive Surgery at the University Hospital Hamburg-Eppendorf for clinical and radiological evaluation, an average of 5.7 years post injury, were divided into two groups (n = 30) depending on radiologically-proven preexisting degenerative changes of the cervical spine. On average the patients with degenerative changes were 11.2 years older than those with healthy vertebral columns and also demonstrated an increase in acute symptoms in the lower cervical spine (cervicobrachial syndrome). The chronicity of individual symptoms such as neck-pain, dizziness, nausea and psychological illness was also observed in both groups. Problems such as paresthesias as well as pain in the shoulder-arm-area appeared to increase in subsequent check-ups, irrespective of the earlier degenerative changes. Patients with typical posterior headaches recovered faster when they had radiologically normal spines. Presenting late, there was a significant accumulation of patients with pre-existing degenerative changes complaining merely of tinnitus. The earlier changes in any individual motion segment do not determine the clinical course of whiplash injuries, but merely represent an area of increased vulnerability to trauma. On the other hand, trauma has not been proven to influence the development or aggravation of degenerative changes in normal or diseased spines. We are not able to differentiate the posttraumatic course from the natural history of the degenerative process, either clinically or radiologically. Considering the involvement of sensitive neurological structures the classical objective organic diagnosis of "whiplash injury" may not be adequate in describing the complaints of patients, and should not be used to justify the rejection of the patients subjective symptoms as mere simulation for financial gains. The evaluation of the patients' X-rays using Arlen's technique sheds no further light on the issue.

Accidents, Traffic↗

PubMed1994

Dissimilar action of two cyclic adenosine-monophosphate analogues on the sodium current in intact rat papillary muscle.

In intact papillary muscles from rat we have found with the loose-patch-clamp technique an increase of the fast cardiac sodium current (INa+) by isoproterenol (ISO). In this study we have tested two membrane permeable analogues of the intracellular second messenger cyclic adenosine-monophosphate (cAMP) to investigate the intracellular pathway: 8-Br-cAMP (50 microM) and the newer developed Sp-5,6-Dichloro-1-beta-D-ribofuranosylbenzimidazole- 3',5'-cyclic-monophosphorothioate (5,6-DCl-cBiMPS, 20 microM). The availability of INa+ was determined with test pulses to +/- 0 mV every 3.5 seconds after 2.5-second conditioning between -130 mV and -50 mV and a holding potential at the resting potential of the cell under examination, and after wash-in of either compound. The peak currents were fit to a Boltzmann equation, and expressed by the maximal attainable current INa+,max, the mid-point potential V1/2, and a steepness parameter alpha. Values are given by mean +/- SEM. 8-Br-cAMP showed a significant shift of the availability curve in the hyperpolarized direction (V1/2 = -82 +/- 2 mV vs -86 +/- 2 mV, n = 5, P < 0.05) with only minor changes of INa+,max and alpha. In contrast, 5,6-DCl-cBiMPS had no significant effect on V1/2 but increased INa+,max by 8% +/- 2% versus control (n = 5, P < 0.05). In an intact muscle preparation we have found that 5,6-DCl-cBiMPS has a similar effect as that observed with the beta-adrenergic agonist ISO (100 nM), whereas 8-Br-cAMP exhibited a dissimilar action.(ABSTRACT TRUNCATED AT 250 WORDS)

8-Bromo Cyclic Adenosine Monophosphate↗

PubMedDate not supplied

[One-stage revision of shoulder arthroplasty in the case of periprosthetic infection].

AIM: Infection of shoulder arthroplasties is rare, but represents a potentially devastating complication. The aim of this work is to show the value of various diagnostic procedures, specify causative pathogens and present the results of one-stage revised patients. METHOD: We performed a retrospective analysis of our 16 consecutive patients with an infected shoulder arthroplasty. RESULTS: In 13 of 16 cases a causative pathogen could be established preoperatively. Staphylococcus and Propioni spp. dominated. Only 9 patients could be followed up because two died, two were lost and three patients were revised because of non-infectious complications. The follow-up time was 5.8 years (13 months-13.25 years). The Constant-Murley score was 33.6 of 100. Eradication of infection was achieved in all patients. In the follow-up time no reinfection has occurred. CONCLUSION: Culturing of the preoperative joint fluid aspirate and the determination of CRP provide an early diagnosing of shoulder arthroplasty infection. One-stage revision arthroplasty with radical debridement and application of antibiotics to the bone cement provide an accurate therapy of periprosthetic shoulder infection.

Aged↗