Biomedical subjects

E Hohmann

Publications and source records attributed to E Hohmann.

12 recordsLinked to original sources

PubMed2006

Comparison of delayed and primary wound closure in the treatment of open tibial fractures.

INTRODUCTION: Primary wound closure in the management of open tibial fractures has generally been discouraged. Several prior studies suggest that infections are not caused by the initial contamination, but are instead the result of organisms acquired in the hospital. Primary wound closure after adequate wound care and fracture stabilisation could therefore be considered a reasonable option. MATERIALS AND METHODS: We analysed 95 patients with open tibial fractures (Gustilo-Anderson type 1 to 3A) treated with primary fracture stabilisation and either delayed wound closure (group I) or primary wound closure (group II), with a minimum follow-up of 12 months. RESULTS: Group I included 46 patients with a mean age of 30.2 years (16-56), and a mean follow-up of 13.5 months (12-18). Group II included 49 patients with a mean age of 33.4 (18-69), and a mean follow up of 13.7 months (12-16). One infection developed in group I (2%), and two infections developed in group II (4%). This difference was not found to have any statistical significance. CONCLUSION: Our results support other recent reports that the infection rate is not increased following primary wound closure after thorough debridement of less severe open fractures. The length of stay following primary closure (group II) was significantly shorter, and that should result in substantially more cost effective care of these serious injuries. We conclude that primary wound closure is a safe option in properly selected cases. Prospective multi-centre studies are needed to further evaluate the safety and efficacy of this treatment alternative.

Adolescent↗

PubMed2006

Effects of menstrual-cycle hormone fluctuations on musculotendinous stiffness and knee joint laxity.

The high risk of anterior cruciate ligament (ACL) injuries in female athletes may be related to hormonal fluctuations resulting in an increased laxity of ligaments and muscles. This study examined changes in lower limb musculotendinous stiffness (MTS) and knee laxity over the course of the menstrual cycle and investigated the interaction of warm-up on MTS. Eleven female netball players aged 16-18 years who were not using hormonal contraceptives and demonstrated regular menstrual cycles participated in this study. Test-sessions were conducted at onset of menses, mid-follicular phase, ovulation and mid-luteal phase. ACL laxity was determined at each test-session using a KT2000 knee arthrometer. MTS was assessed prior to, and following a standardised warm-up. Repeated measures ANOVA revealed significant (P < 0.05) main effects of test-session and warm-up on MTS. MTS was found to significantly decrease by 4.2% following the warm-up intervention. MTS was significantly lower at week 3 (ovulatory phase) in contrast to weeks 1 and 2 (8.7 and 4.5%, respectively). For knee laxity measures, repeated measures ANOVA revealed no significant (P < 0.05) differences across the menstrual cycle. A reduction in MTS results in greater reliance on reflexive response from the contractile components of the muscle due to a decreased contribution from passive elastic structures and will also increase electromechanical delay. Given that extreme loads are applied to the knee joint within milliseconds, the contractile components cannot respond quickly enough to counteract these sudden and potentially damaging forces. These effects are augmented following a moderate warm-up. Oestrogen fluctuations had no significant effect on anterior knee laxity, however, the effects on MTS over the 28-day cycle were considerable. Future studies should use matched subjects who are using the monophasic oral contraceptive pill to investigate the effects of oestrogen supplementation on lower limb MTS.

Adolescent↗

PubMed2005

[Osteoarthritis from long-distance running?].

Long distance running has become a fashionable recreational activity. This study investigated the effects of external impact loading on bone and cartilage introduced by performing a marathon race. Seven beginners were compared to six experienced recreational long distance runners and two professional athletes. All participants underwent magnetic resonance imaging of the hip and knee before and after a marathon run. Coronal T1 weighted and STIR sequences were used. The pre MRI served as a baseline investigation and monitored the training effect. All athletes demonstrated normal findings in the pre run scan. All but one athlete in the beginner group demonstrated joint effusions after the race. The experienced and professional runners failed to demonstrate pathology in the post run scans. Recreational and professional long distance runners tolerate high impact forces well. Beginners demonstrate significant changes on the post run scans. Whether those findings are a result of inadequate training (miles and duration) warrant further studies. We conclude that adequate endurance training results in adaptation mechanisms that allow the athlete to compensate for the stresses introduced by long distance running and do not predispose to the onset of osteoarthritis. Significant malalignment of the lower extremity may cause increased focal loading of joint and cartilage.

Adult↗

PubMed2003

[Biomechanical investigations for the development of a SLAP-II-lesion].

The superior labral-biceps-tendon-complex forms an anatomical and functional unit and combines static and dynamic elements of shoulder stability. At present, only theoretical hypotheses exist on the etiology of the microtraumatic SLAP-II-lesion. To gain further insight into this, an instrument was developed to simulate throwing motions such as the late-cocking/early acceleration phase as well as deceleration/follow-through. Sixteen freshly frozen shoulder specimens were tested, varying the loads on the biceps tendon (25 N, 50 N, 100 N) and the compression of the humeral head against the glenoid (25 N, 50 N, 80 N). Each shoulder had to run through a certain number of cycles during the particular phase of throwing. The tests were stopped after a SLAP-II-lesion was observed, or after a limit of 15,000 cycles. Every 1,000 cycles the results of the tests were checked arthroscopically. A SLAP-II-lesion developed in only 10% of the specimens during the acceleration/ late cocking phase whereas in the deceleration/ follow-through phase 83% developed such a lesion. According to our results, the deceleration/follow-through of the throwing motion seems to be responsible for creating microtraumatic SLAP-II-lesions. One reason is the loss of the centering function of the long head of the biceps tendon during total internal rotation, another is the increased posterosuperior translation of the humeral head in this position, which leads to a non-physiological contact, creating lesions in this area due to the large sheering forces.

Acceleration↗

PubMed2003

[Epidemiology of recreational runners].

Running has become a very popular sport in Europe. We clinically examined the feet of 92 recreational runners and assessed their knowledge of their own foot anatomy with a questionnaire. Additionally a podogram was performed by an experienced podiatrist. 41 runners trained for more than 5 years, 12 between 3-5, 28 between 1-3 and 11 less than one year. The mean age was 35.4 years. The majority had weekly distances of less than 20 km (n = 43) and 20-40 km (n = 28), 14 40-60 km and only 6 runners were running more than 60 km per week. We could define two groups: one group as the sedentary runner with distances less than 20 km over a minimum period of 3 - 5 years and the competitive runner with distances above 40 per week over at least 3 years. Most of the runners run on tarred or gravel surfaces or a combination of those. The knowledge of the own foot anatomy and biomechanics was poor. Only 50% were correct in identifying their anatomy. 30% of all runners have been given orthotics of which only 50% demonstrated an improvement in symptoms.

Adolescent↗

PubMed1993

The PhoP virulence regulon and live oral Salmonella vaccines.

The PhoP virulence regulon is essential to Salmonella typhimurium mouse typhoid fever pathogenesis and survival within macrophages. This virulence regulon is composed of the PhoP (transcriptional regulator) and PhoQ (environmental sensor) proteins and the genetic loci they positively (pags for PhoP activated genes) and negatively (prgs for PhoP repressed genes) regulate. Three regulated loci pagC, pagD, and prgH, when singly mutated, affect the virulence of S. typhimurium for mice. Strains with phoP locus mutations are effective as live vaccines in mice, and strains with a constitutive regulatory mutation, a point mutation in PhoQ, can protect mice against typhoid fever when only very few organisms are administered. The addition of various PhoP regulon mutations further attenuates aroA mutants of S. typhimurium, suggesting that these mutations would be useful in further attenuating vaccine strains with metabolic pathway mutations. The phoP, phoQ, pagC, and pagD genes are highly conserved between S. typhimurium and S. typhi and may be valuable as mutations in live vaccines for human typhoid fever. A plasmid suicide vector that allows deletion of the pagC gene and stable insertion of heterologous antigen genes within the deleted pagC locus has been constructed and used successfully in S. typhimurium and S. typhi.

Administration, Oral↗

PubMed1981