Biomedical subjects

K E Rehm

Publications and source records attributed to K E Rehm.

At least 19 recordsLinked to original sources

PubMed2006

40Ca(alpha, gamma)44Ti reaction in the energy regime of supernova nucleosynthesis.

The 44Ti(t1/2=59 yr) nuclide, an important signature of supernova nucleosynthesis, has recently been observed as live radioactivity by gamma-ray astronomy from the Cas A remnant. We investigate in the laboratory the major 44Ti production reaction 40Ca(alpha, gamma)44Ti (Ec.m. approximately 0.6-1.2 MeV/u by direct off-line counting of 44Ti nuclei. The yield, significantly higher than inferred from previous experiments, is analyzed in terms of a statistical model using microscopic nuclear inputs. The associated stellar rate has important astrophysical consequences, increasing the calculated supernova 44Ti yield by a factor approximately 2 over previous estimates and bringing it closer to Cas A observations.

Journal Article↗

PubMed2006

[Multislice CT in diagnostic work-up of polytrauma].

BACKGROUND: In severely injured patients, diagnostic procedures should be as brief as possible. With the use of spiral CT technology, the time required for diagnosis is minimized. QUESTION: Do severely injured patients benefit when primary diagnostic examinations are completed in less than 30 min? How much time is required for primary emergency department (ED) care and how much in the CT scanner? MATERIAL AND METHODS: Between 31 July 2001 and 31 December 2003, severely injured patients with ISS scores over 16 underwent total body spiral CT scans (Siemens Somatom Volume Zoom Multislice CT) after initial ultrasonography. One hundred patients (M:F=25:75) with an average age of 42 years (range: 3-81 years) were evaluated retrospectively. The average ISS score was 32.8+/-12 points (range: 17-75 points). RESULTS: The average time in the ED, prior to CT, was 33+/-14 min. The CT scans lasted 16+/-5 min and the total diagnostic time was 48+/-14 min. Fifty percent of patients were taken immediately to the operating room. The mortality rate in hospital was 13%. The average hospital stay was 30 days, with an average ICU stay of 10 days. CONCLUSION: The shorter the time spent in the ED, the shorter the stays in ICU and in total hospitalization were, regardless of injury severity. With structured management and shortening of diagnostic time with spiral CT, the time in the ED was decreased from 85 to 48 min.

Adolescent↗

PubMed2006

[Implantation of matrix-free cartilage transplants in standardized defects in sheep knee joints].

The goal of the current investigation was to make a comparative analysis of regenerative tissue after autologous de novo cartilage transplantation on the femoral condyles of sheep after a chondral defect. One chondral defect measuring 4 mm in diameter was placed in the center of one medial femoral condyle of each of 48 Suffolk sheep. Twelve defects were left to heal spontaneously, 16 defects were covered with periosteal flaps, and 20 defects were filled with autologous de novo cartilage graft. Macroscopic and microscopic assessments were performed at 26 and at 52 weeks. Regeneration was significantly better (p<0.05) in the transplant group than in the control groups at both 26 weeks and 52 weeks. The differences were most evident in the grade of defect filling, cartilage stability, cell distribution, and matrix assessments. Transplantation of immature, autologous de novo cartilage leads to qualitatively better regeneration both macro- and microscopically than does periosteal flap placement alone. The transplanted, immature cartilage tissue undergoes maturation in vivo. The regenerated tissue has hyaline-like features.

Animals↗

PubMed2006

[Lecture disasters - and how to prevent them].

Presentations at medical conferences can sometimes confuse or compromise understanding of current topics. Although considerable time and financial costs may be taken to be present at such events, all too often one must go through inferior presentations that are poorly structured and do not contribute to one's understanding of the topic at hand. A good presentation is distinguishable by the clear intentions of the speaker to give a good lecture. The presenter has worked extensively with his topic and is familiar with the audience. The presentation has a clear structure and finishes with a take-home message. The speaker takes the listener from his previous level of knowledge to a new understanding. To do so, both voice and body language are used. The supporting slides are simple and direct, and not overloaded with information. The speech conforms exactly with the pre-determined time limit.

Audiovisual Aids↗

PubMed2005

Stellar (n,gamma) cross section of 62Ni.

The 62Ni(n,gamma)63Ni(t(1/2)=100+/-2 yr) reaction plays an important role in the control of the flow path of the slow neutron-capture (s) nucleosynthesis process. We have measured for the first time the total cross section of this reaction for a quasi-Maxwellian (kT=25 keV) neutron flux. The measurement was performed by fast-neutron activation, combined with accelerator mass spectrometry to detect directly the 63Ni product nuclei. The experimental value of 28.4+/-2.8 mb, fairly consistent with a recent calculation, affects the calculated net yield of 62Ni itself and the whole distribution of nuclei with 62<A<90 produced by the weak s process in massive stars.

Journal Article↗

PubMed2005

Neutron spectroscopic factors in 9Li from 2H(8Li,p)9Li.

We have studied the 2H(8Li,p)9Li reaction to obtain information on the spins, parities, and single-neutron spectroscopic factors for states in 9Li, using a radioactive 8Li beam. The deduced properties of the lowest three states are compared to the predictions of a number of calculations for the structure of 9Li. The results of ab initio quantum Monte Carlo calculations are in good agreement with the observed properties.

Journal Article↗

PubMed2005

[ Intramedullary nailing (ESIN) in clavicular pseudoarthroses. Results of a prospective clinical trial].

This prospective clinical trial was performed to assess healing, clinical outcome and complications after intramedullary nailing of midshaft clavicular nonunions. Over 2.5 years, 14 patients were included. Exclusion criteria were pathological fractures, bony defects, previous operative therapy, atrophic and infection pseudarthrosis and the patient's age: <18 years or >70 years. Results were evaluated after 3, 6, 12 and 18 months. Beginning 3 months after the operation, pain (VAS), subjective satisfaction, Constant score and DASH score were significantly better than preoperatively during the follow-up period (p<0.001). There were no infections, no implant displacements or refractures.Intramedullary fixation of midshaft clavicular nonunions with an elastic titanium nail is a safe, minimally invasive surgical technique, producing excellent functional and cosmetic results without additional bone grafting.

Adult↗

PubMed2005

[Treatment of mid-clavicular fractures in adults. Early results after rucksack bandage or elastic stable intramedullary nailing].

OBJECTIVES: The aim of this prospective study was to compare the results achieved in two groups of patients treated for mid-clavicular fracture. METHODS: The first group of 27 patients was treated nonoperatively with a rucksack bandage, whereas the second group underwent intramedullary fixation with a titanium pin, using a minimally invasive technique. Within the follow-up period of 6 months, results were evaluated seven times. RESULTS: During the whole period significantly (p<0.05) better results were observed in the group of operated patients concerning shoulder function, Constant score, DASH score, personal satisfaction, pain, and cosmetic result. In the second group return to work occurred in less than half the time of the first group. CONCLUSION: Intramedullary nailing of mid-clavicular fractures is a safe and minimally invasive operation technique. Early functional and cosmetic results are not worse than results after nonoperative treatment with a rucksack bandage.

Adolescent↗

PubMed2004

Laser spectroscopic determination of the 6He nuclear charge radius.

We have performed precision laser spectroscopy on individual 6He (t(1/2)=0.8 s) atoms confined and cooled in a magneto-optical trap, and measured the isotope shift between 6He and 4He to be 43 194.772+/-0.056 MHz for the 2(3)S1-3(3)P2 transition. Based on this measurement and atomic theory, the nuclear charge radius of 6He is determined for the first time in a method independent of nuclear models to be 2.054+/-0.014 fm. The result is compared with the values predicted by a number of nuclear structure calculations and tests their ability to characterize this loosely bound halo nucleus.

Journal Article↗

PubMed2004

Is the nuclear spin-orbit interaction changing with neutron excess?

The difference in the energies of the lowest states corresponding to the two nodeless single-particle orbitals outside the Z=50 closed proton shell, h(11/2) and g(7/2), increases with neutron excess. We have measured the Sn(alpha,t) reaction for all seven stable even Sn isotopes and found that the spectroscopic factors are constant for these two states, confirming their characterization as single-particle states. The trend in energies is consistent with a decrease in the nuclear spin-orbit interaction. A similar trend, also suggesting a decreasing spin-orbit splitting, is seen in the energies of the neutron single-particle states outside the N=82 core, i(13/2) and h(9/2).

Journal Article↗

PubMed2004

Reevaluation of the 22Na(p,gamma) reaction rate: implications for the detection of 22Na gamma rays from novae.

Understanding the processes which create and destroy 22Na is important for diagnosing classical nova outbursts. Conventional 22Na(p,gamma) studies are complicated by the need to employ radioactive targets. In contrast, we have formed the particle-unbound states of interest through the heavy-ion fusion reaction, 12C(12C,n)23Mg and used the Gammasphere array to investigate their radiative decay branches. Detailed spectroscopy was possible and the 22Na(p,gamma) reaction rate has been reevaluated. New hydrodynamical calculations incorporating the upper and lower limits on the new rate suggest a reduction in the yield of 22Na with respect to previous estimates, implying a reduction in the maximum detectability distance for 22Na gamma rays from novae.

Journal Article↗

PubMed2004

[Pitfalls and complications of elastic stable intramedullary nailing (ESIN) of femoral fractures in infancy].

BACKGROUND: The aim of this prospective study was to evaluate the intra- and postoperative problems as well as the complications of elastic stable intramedullary nailing (ESIN) of femur fractures in children. PATIENTS AND METHODS: 47 consecutive children, mean age 6 years, were reviewed clinically and radiologically until hardware removal and after this annually. Mean time of follow up was 37 months. RESULTS: Intraoperatively one cortex perforation and one displacement of a third fragment occurred. Two correction operations were necessary: In one case due to an implant displacement and in another case due to an unacceptable loss of reduction. There were no infections, non union, implant breakage, refracture or disturbance of growth. CONCLUSIONS: ESIN is a safe procedure in femoral shaft fractures of children. Most of the problems and complications can be avoided by a careful consideration of the indication and a correct operation technique.

Bone Nails↗

PubMed2004

[Experience with elastic stable intramedullary nailing (ESIN) of shaft fractures in children].

The aim of this prospective clinical controlled trial was to investigate the early and midterm results of shaft fractures in children treated with elastic stable intramedullary nailing (ESIN). From January 1997 to December 2001, elastic stable intramedullary nailing was carried out on 112 children with 118 diaphyseal fractures. The mean age was 7.7 years. There were 51 fractures of the lower arm, 46 femoral fractures, 14 of the lower leg, and 7 of the humerus. A total of 92 children have been followed up for more than 12 months. The mean time of follow-up was 38 months.The mean time of fluoroscopy was 2.2 min. Open reduction was necessary in 3.4 %. In children with injuries of the lower extremity, full weight bearing was achieved after a mean period of 9.3 days. In 1.8% of the children, reoperation was necessary within the first 10 days after the operation. In 3.6 % there was painful skin irritation due to the protruding end of a nail. No infection or delayed union was observed. Implant removal was done after a mean time of 5.6 months. There was no rotational or angular deformity of more than 5 degrees in children with isolated fractures of the lower extremity. Mean lengthening of the injured leg was 2.4 mm. In three children who had fractures of the upper extremity, a deficit in range of motion of the adjacent joints was detected. The current results show that intramedullary fixation of displaced diaphyseal fractures in children with a flexible titanium nail is a safe, minimally invasive surgical technique producing excellent functional and cosmetic results.

Arm Injuries↗

PubMed2004

[Use of the injectable bone cement Norian SRS for tibial plateau fractures. Results of a prospective 30-month follow-up study].

Reduction of the depressed joint surface in tibial plateau fractures often leaves large cancellous bone defects. These metaphyseal voids are typically filled with autogenous bone grafts that can cause a significant donor site morbidity. The use of injectable bone cement offers the opportunity to support the reduced joint surface without bone grafting. The aim of this study was to evaluate the clinical and radiological outcome as well as the period of partial weight bearing after the use of Norian SRS in tibial plateau fractures. Twenty-one patients with a mean age of 48 years were included in this prospective trial. According to the AO/OTA Classification, there were seven fractures of type B2, ten B3, one C1, one C2, and two fractures of type C3. The period of partial weight bearing was 3.7 weeks. In 18 patients the follow-up was more than 24 months. After a mean follow-up of 30 months, the Lysholm score was 87.9 at mean. The radiological part of the Rasmussen score was excellent and good in eight cases each and fair in four cases. Soft tissue reactions due to the cement were not observed. On all radiographs taken 36 months after the operation the cement bloc was still visible. The results show that Norian SRS can be used to fill metaphyseal bone defects in tibial plateau fractures. Clinical and radiological results are comparable to those of fractures treated with autologous bone graft. The high compression strength allows early full weight bearing without the risk of secondary loss of reduction.

Adult↗

PubMed2004

Soft tissue reactions of different biodegradable polylactide implants.

Soft tissue reactions resulting from biodegradable polylactide implants to bone have not been adequately examined during their 3-year degradation period. An osteotomy was performed on the medial femoral condyle of 36 sheep and secured by either three poly-L-DL-lactide pins (70/30) (Polypin) or three composite pins [10% beta-tricalcium phosphate (beta-TCP) (90/10)]. A histological examination was performed on the synovial membrane and lymph nodes after 3, 18 and 36 months. After 18 months two non-specific, minor reactions of the synovial membrane were observed in the composite pin group. In both groups different reactions of both inguinal lymph nodes were observed. These had no statistical relevance and could not be clearly attributed to the implants. Due to the slow degradation process of biodegradable polylactide implants, there is no clinically relevant inflammation of either joint or lymph nodes. The addition of 10% beta-TCP did not result in any significant enhancement.

Animals↗

PubMed2003

Determination of the 8B neutrino spectrum.

We have measured the total energy of the alpha particles following the beta decay of 8B by implanting 8B into a planar silicon surface barrier detector. Calibration was performed using alpha particles following the beta decay of 20Na, similarly implanted. The alpha spectrum is used to infer the 8B neutrino spectrum which is an important input in the interpretation of experiments that detect energetic neutrinos from the Sun. The alpha spectrum reported here is in disagreement with the previous best measurement which used two detectors in coincidence.

Journal Article↗

PubMed2003

[Candida infection in hip alloarthroplasty].

A 46-year-old polytoxicomanic patient underwent a total hip replacement for necrosis of the femoral head. The patient suffered additionally from chronic pancreatitis with insulin-dependent diabetes and polyneuropathy. Three weeks later he developed a deep wound infection followed by surgical revision. The infection persisted despite further revision operations and systemically and locally applied antibiotics. After removal of the prosthesis,microbiology revealed Staphylococcus aureus, enterococcus,and Candida parapsilosis. Five additional revision operations, application of suction-irrigation drainage, and systemically administered antibiotics could not stop the infectious process. The patient was transferred to our institution 3 months after primary surgery. The joint defect was filled with a PMMA Palacos spacer. This time biopsies were only positive for Candida albicans. After 12 days of antifungal therapy with fluconazole,microbiological biopsies were sterile. The spacer was removed and femoral extension applied. After 4 weeks of further antifungal therapy, a revision prosthesis was implanted. Until now no signs of infection have appeared.

Antifungal Agents↗

PubMed2003

[Risk factors for the development of pneumonia in multiple injured patients. Results of a prospective clinical trial].

Pneumonia is the most common infectious complication in multiple trauma patients. In a prospective clinical cohort study, 266 multiply injured patients were examined for the development of pneumonia. Various risk factors were tested in uni- and multivariate analyses. Three different definitions of pneumonia were used in order to examine how results depended on definition. The incidence of pneumonia was 41%, but varied with definition (30-50%). Injuries to the thorax, head,and abdomen were associated with a significantly increased risk of pneumonia (adjusted relative risk: 1.77, 1.97,and 1.52, respectively).Furthermore, increasing age led to a higher risk of pneumonia. Although the primary analysis revealed a higher pneumonia risk in male patients (adjusted relative risk: 2.23; 95% CI: 1.43-3.05), this result could not be consistently reproduced when using other definitions of pneumonia. Trunk and head injuries and age are proven risk factors for developing posttraumatic pneumonia. The association between male gender and an increased rate of infectious complications remained questionable.

Abbreviated Injury Scale↗