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Biomedical subjects

N Haas

Publications and source records attributed to N Haas.

At least 19 recordsLinked to original sources
PubMed1992

Expression of the high affinity IgE-receptor on human Langerhans' cells. Elucidating the role of epidermal IgE in atopic eczema.

Epidermal Langerhans' cells have previously been shown to bear IgE molecules, particularly in atopic dermatitis skin. Using two highly specific antibodies against the antibody-binding chain of the high affinity IgE-receptor, 29C6 and 6F7, we here provide evidence that Langerhans' cells express this receptor in both normal skin (foreskin) and in lesional skin of patients with atopic and stasis eczema. A specific antibody against the low affinity IgE-receptor, Tü1, showed only a low expression of this receptor. This finding has important potential functional implications for the role of Langerhans' cells in transepidermal, IgE-mediated allergy.

Antibody Affinity↗
PubMed1992

[Osteosynthesis of distal radius fractures with biodegradable fracture rods. Results of two years follow-up].

Forty distal fractures of the radius were stabilized with biodegradable polyglycolic acid rods (Biofix). A forearm plaster cast was fit for 4 weeks. Nine patients developed late (4 to 16 weeks) aseptic inflammatory reactions at the pin site, which were treated by débridement. The histological specimens showed giant-cell phagocytosing fragmented polyermic debris. In two cases a bacterial wound infection occurred secondary to débridement. All local reactions healed within 4 weeks. A classification system and treatment regimen for these inflammatory reactions are proposed. Thirty-four patients (including those with local foreign body reaction) were available for the 2-year follow-up. The anatomical results of fracture reduction on the postoperative and follow-up radiograms were the same, confirming good mechanical fracture stabilization. According to the Sarmiento score, the overall results were excellent and good in 31 cases. In one of the three fair cases, the result was clearly due to the initial local foreign-body reaction. Because of the high incidence of local inflammatory reaction, for now clinical application of biodegradable implants seems problematic despite the good overall 2-year results. This should only be advocated for well-controlled prospective studies using implants with improved biocompatibility.

Adult↗
PubMed1992

[Classification and management of complex pelvic trauma].

Complex pelvic traumas are pelvic fractures accompanied by pelvic soft tissue injuries. Mortality in major pelvic fractures with associated soft tissue injuries is high, and these injuries can pose a more complex range of therapeutic problems. Uncontrolled bleeding and septic complications are the main causes of death. There has been extensive work on grading pelvic ring fractures, but less attention has been paid to grading the accompanying soft tissue damage. Therefore, a grading system for pelvic injuries was developed that takes the soft tissue damage into account more than the fracture classification did when used alone. It is a point system that considers the fracture itself, the soft tissue injuries, including lesions in the pelvic organs, vessels and nerves, and the general concomitant injuries. From 1972 to 1990 the clinical course and outcome of 132 patients with complex pelvic traumas were reviewed. The mortality was 34.8%. Eighty-three of the patients (62.9%) underwent immediate laparotomy and in 68 patients (51.7%) open reduction and internal fixation of the unstable pelvic ring were performed. For better primary treatment of patients with complex pelvic injuries, a trauma algorithm is introduced. It leads to important therapeutic steps after brief clinical, ultrasonic and radiological assessments. The major questions in the flow chart take the pelvic ring and hemodynamic instability into account. Immediate laparotomy, surgical control of hemorrhage, and open reduction and internal fixation of an unstable pelvic ring represent the most important requirements for successful treatment.

Adolescent↗
PubMed1992

[Determining indications and osteosynthesis techniques for the pelvic girdle].

1566 patients with fractures of the pelvis were treated at the Department of Traumatology of the Hannover Medical School between 1972 and 1990: 1350 patients had fractures of the pelvic ring, 216 isolated acetabulum fractures, 398 combinations of pelvic ring fractures and acetabular involvement; 718 of these patients were admitted with severe polytrauma. For 1254 patients a complete file was available for clinical and radiological evaluation of fracture distribution, classification (Tile and anatomical location) and concomitant injuries. During the observation period, significant increase in the severity of the trauma, the severity of the pelvic fractures and the rate of internal stabilization, especially of the posterior pelvic ring was observed. The overall mortality after pelvic fractures was 18.1%. This mortality depended significantly on the Hannover Polytrauma Score (PTS) and the associated pelvic and extrapelvic blunt trauma. Internal fixation of pelvic fractures was performed in 195 patients. This experience has now led to standardized procedures for the different fracture locations. With the task of minimizing soft tissue trauma and reducing the implant size, more differentiated treatment of sacral fractures is now applied. Adapted small fragment implants ("local osteosyntheses") can be applied, with an unilateral longitudinal dorsal incision providing an excellent overview over the fracture line. For internal fixation of sacral fractures, involvement (penetration by screws, transfixation) of the sacroiliac joint is avoided whenever possible. In our experience early open reduction and internal fixation of pelvic fractures facilitates the management of these severely injured patients.

Adolescent↗
PubMed1991

Localization of boar sperm proacrosin during spermatogenesis and during sperm maturation in the epididymis.

The localization of proacrosin was determined by using colloidal gold labeling and electron microscopy of boar germ cells during spermiogenesis to post-ejaculation. Proacrosin was first localized in round spermatids during the Golgi phase of spermiogenesis; it was associated with the electron-dense granule, or acrosomal granule that was conspicuous within the acrosome. It remained within the acrosomal granule during the cap and acrosome phases of spermiogenesis. At these stages, there was no apparent association of the proacrosin molecule with the acrosomal membranes. During the maturation phase of spermiogenesis, proacrosin was seen to become dispersed into all regions of the acrosome except the equatorial segment. When sperm from different segments of the epididymis and ejaculated sperm were examined, localization was observed throughout the acrosome except for the equatorial segment. Here proacrosin appeared to be localized on both the inner and outer acrosomal membranes as well as with the acrosomal matrix, although further studies are required to verify the membrane localization. No labeling was seen on the plasma membrane. These data suggest that the synthesis and movement of proacrosin to sites in the acrosome are controlled by an as yet unknown process. The absence of proacrosin on the plasma membrane of mature ejaculated sperm makes it unlikely that this enzyme plays a role in sperm-zona adhesion prior to capacitation.

Acrosin↗
PubMed1991

Treatment of femoral shaft fractures in children by external fixation.

Non-operative management is still the treatment of choice for closed fractures of the femoral shaft in children. Indications for operative intervention would include: children with multiple injuries; severe soft tissue damage; cases where reduction is difficult to maintain; and children not suitable for management by traction. Since 1984, 16 children (mean age 10.3 years) have had stabilization of their femoral shaft fractures by external fixation (Monofixateur) in the Trauma Department of the Hannover Medical School. The external fixation remained in place for a mean of 63 days. Of the 16 children, 15 have been reviewed, with a mean follow-up of 28.2 months. No children who were completely managed with this fixation had any clinically relevant malalignment, but six cases had up to 2 cm difference in leg length. Our observations and experience show that external fixation is a useful alternative for the operative management of femoral shaft fractures in children. It produces good stability, is less invasive, and allows early mobilization. In order to avoid differences in leg length, we recommend a good anatomical reduction with the external fixation being carried out as early as possible.

Adolescent↗
PubMed1991

A review of the therapeutic concept and results of operative treatment in acute and chronic lesions of the cervical spine: the Hannover experience.

A therapeutic concept for the treatment of acute and chronic cervical spine lesions is presented. Unstable fractures and dislocations of the cervical spine should be reduced as soon as possible. Most frequently, we employ the anterior approach using the Smith and Robinson technique (37) with the addition of an H-shaped plate. The posterior approach is mainly indicated for the release of irreducible locked facets. Unstable odontoid fractures, especially those in group II of Anderson and d'Alonzo (3), are stabilized by screw osteosynthesis. Between 1971 and 1989, 306 patients with cervical spine lesions were treated surgically. In these cases, there were 205 acute injuries and 52 chronic instabilities. Forty-nine patients had tumors or metastases. Ninety-two patients with acute injuries (group I) and 24 with chronic lesions (group II) were reexamined. Out of 53 group I patients, the neurologic symptoms improved in 45 cases (85%), and in 30 of these (mainly with radicular compression syndromes) a complete recovery was noted. Seventy-two percent of the patients were symptom-free. Seventy-four percent of the acute and 58% of the chronic lesions showed a good or very good result having little or no limitation of motion and minimal or no pain. Irrespective of neurologic deficits, 89% of the acute traumatized patients were able to work after 5 months. The rate of pseudarthrosis was 2%. The risks of an anterior interbody arthrodesis are small when using a careful and standardized operative technique. It allows an early functional treatment and shortens the rehabilitation time.

Acute Disease↗
PubMed1991

Anterior plating in thoracolumbar spine injuries. Indication, technique, and results.

The selection of surgical approach for patients suffering from acute thoracolumbar spinal trauma is presently imbued with great controversy. The surgical method chosen depends on the type of fracture, anatomic and biomechanical factors, and the habits and experience of the surgeon involved. Due to new techniques for the posterior approach and the use of internal fixators, the indications for the anterior approach must be reassessed. The primary indication for anterior decompression and grafting is narrowing of the spinal canal with neurologic deficits that cannot be resolved by any other approach. Additional indications are seen in patients with vertebral body fractures with complete comminution and dislocation, noncorrectable burst fractures, and late misalignments. After removal of vertebral body and intervertebral disc fragments, autogenous bone should preferably be used for interposition. Different plates can be used for instrumentation. While anterior plates most often offer complete stability for the thoracic spine and a dorsal plating in this region can turn out to be quite difficult, in the lumbar spine, especially with destruction of additional posterior structures, one must think of subsequent surgical intervention for increased stability and compressive posterior fusion with short-armed internal fixators. So far, we have gained experience from treating 39 patients with anterior decompression and stabilization. One of 19 patients with Frankel Grades A and B and 50% of the remaining 20 patients had improved one Frankel grade. Only a few of the patients with incomplete neurologic symptoms had back pain. All except for one returned to work. According to radiologic examinations, the average loss of correction amounted to 7%.

Adult↗
PubMed1991

Detection of human papillomaviruses in paraffin-embedded condylomata acuminata--comparison of immunohistochemistry, in situ hybridization, and polymerase chain reaction.

The polymerase chain reaction (PCR) is used for detection of human papillomavirus (HPV) DNA in paraffin-embedded tissue sections of condylomata acuminata. Incorporation of biotinylated nucleotides during the amplification process allows a highly sensitive, fast, and non-isotopic detection of viral DNA in a subsequent Southern dot blot. In 100% (13 of 13) of histologically confirmed condylomata, HPV-6 or -11 could be detected by polymerase chain reaction. By in situ hybridization 77% (10 of 13) and by immunohistochemistry (IHC) 69% (nine of 13) positive results were obtained. Because HPV genital infection is linked to penile and cervical dysplasia, polymerase chain reaction provides a powerful and highly sensitive tool for epidemiologic studies on sexual transmission of HPV.

Adult↗
PubMed1991

[Unreamed tibial nail in tibial shaft fractures with severe soft tissue damage. Initial clinical experiences].

In a prospective study, since March 1989, 55 tibial shaft fractures have been treated with a new, unreamed solid tibial nail (UTN). This nail was initially designed as a temporary implant. The first 33 cases with second or third degree soft tissue damage were reviewed 6 months or more after the operation. Fractures were classified according to Müller: 6 type A (18.2%), 15 type B (45.5%), and 12 type C (36.7%). In 9 cases (27.3%), there was GII (n = 4) or GIII (n = 5) closed soft tissue damage according to Tscherne's classification. The 24 open fractures (72.7%) comprised 11 OII, 3 OIIIA and 10 OIIIB fractures (Gustilo classification). 24 patients (72.7%) were polytraumatized, the mean PTS (Hannover Polytrauma Score) was 18 points (range: 8-65 points). All fractures were stabilized without reaming. The implant diameter was 8mm (n = 14) or 9 mm (n = 19). Static locking was performed in 31 cases. Dermatofasciotomy was necessary because of compartment syndrome in 14 cases. In 1 grade IIIB open fracture soft tissue coverage was performed with a latissimus dorsi myocutaneous free flap 4 days after nailing. In 32 of the 33 cases the use of an additional cast or brace was not necessary during the follow-up treatment; 1 patient had a cast for 8 weeks for the treatment of accompanying injuries. Full weight-bearing was achieved in 5 cases within 3 weeks, in 16 cases within 12 weeks, and in 30 cases within 26 weeks. In 16 cases (48.5%) the interlocking screws were removed after 5-26 weeks (mean: 10 weeks).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

[New trends in the management of shaft fractures].

There is no major change in the indication of upper extremity fractures, although there is further refinement of plate design (LC-DCP), plate material (titanium), and operative technique ("biological osteosyntheses"). For lower extremity fractures, the external fixator has shown excellent results in the early phase of treatment, with some disadvantages the late phase. If a change to an intramedullary nail is planned, this should be performed in the early phase of treatment. The concept of the "pinless fixator" has shown great advantages for temporary stabilization, although further technical development is necessary. The claw interlocking nail allows easy distal locking without using X-rays. Unreamed nailing, with the advantage of less damage to the cortical blood supply and reduced pulmonary risk, will be of increasing importance, if the trend seen in current studies is confirmed.

External Fixators↗
PubMed1991

[Initial clinical experience with osteosynthesis of femoral shaft fractures with a newly developed intramedullary implant (claw interlocking nail)].

The implantation of distal interlocking screws in interlocking nailing can be difficult and time-consuming. With the AO Universal Femoral Nail as the basis, an implant was designed with which distal interlocking is accomplished from the inside of the nail by means of a simple claw mechanism. Instrumentation and interlocking are possible from the proximal standard approach, so that an additional operation adjacent to the knee (which is necessary when interlocking bolts are used) is superfluous; neither for the insertion nor for the removal of the interlocking mechanism is an image intensifier necessary. We stabilized 24 femoral shaft fractures with this new interlocking nailing device [20 fresh fractures, 3 refractures and 1 pathologic fracture caused by tumor metastasis from chronic myeloid leukemia (CML)]. The mean age of the patients concerned was 34.8 years (18-57 years). Fractures were classified according to the Müller classification with 11 type-A fractures (45.8%), 9 type-B fractures (37.5%) and 4 type-C fractures (16.7%). There were only 2 cases (8.3%) with open fractures. In 11 cases (45.8%) the fracture was located in the midshaft region, in 6 cases (25.0%) in the proximal shaft, and in 7 cases (29.2%) in the distal femoral shaft. Multiple trauma was present in 11 patients (45.8%), while in 8 patients (33.2%) the femoral shaft fracture was the only major injury. Full weight-bearing was allowed after a mean of 4.4 weeks (0.7-8.2 weeks). In 1 case we saw a deep venous thrombosis with pulmonary embolism obvious on clinical examination and scintigraphy. Two patients died of their multiple trauma, and of cachexia the patient with the CML metastasis died 6 weeks after stabilization.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

The role of supplemental lag-screw fixation for open fractures of the tibial shaft treated with external fixation.

Ninety-nine open fractures of the tibial shaft were treated with unilateral external fixation with or without supplemental lag-screw fixation. We compared the results in forty-four fractures in which only external fixation was used (control group) with those in fifty-five fractures that were stabilized with lag-screws and external fixation, and we found no statistically significant differences between the two groups with respect to the time to full weight-bearing, the time to union, or the rates of delayed union, osteomyelitis, malunion, superficial or deep pin-track infection, or loosening of the pins. The limbs in which the fracture was treated with external fixation and supplemental lag-screws had more than twice the rate of refracture of the control limbs (11 compared with 5 per cent), and the percentage of fractures having supplemental lag-screw fixation that needed bone-grafting to achieve union was more than twice that in the group treated with external fixation alone. We concluded that the routine use of supplemental lag-screw fixation is not indicated in patients who have an open fracture of the tibial shaft that has been stabilized with external fixation.

Adolescent↗
PubMed1990

Selective, delayed increase in transfer constants for cerebrovascular permeation of blood-borne 3H-sucrose following forebrain ischaemia in the rat.

Experiments were conducted to explore the time course of changes in blood-brain barrier (BBB) permeability that may occur in the 2-vessel occlusion model of stroke in the rat. Anaesthetized Sprague-Dawley rats underwent 10 min of cerebral ischaemia produced by bilateral carotid occlusion plus haemorrhagic hypotension. After 6 min, or 3, 6, 18, 24, 48 h recovery and re-anaesthetization, an i.v. injection of 3H-sucrose was permitted to circulate for 30 min. Regional transfer constants (Ki) for BBB permeation of sucrose were calculated from the ratio of sucrose concentration in parenchyma relative to the time-integrated plasma concentration. In the 6-min group, all cerebral regions showed evidence of early BBB leakiness (increase in Ki above non-stroke baseline) which was maximal in forebrain cortex. This effect was diminished at subsequent time points, except in striatum and hippocampus which exhibited delayed intensification of opening, maximal in the 6 h group. Ki values had largely normalized by 24 h. Ki values were also determined 6 min, 6 h and 24 h after a 20-min stroke procedure. Early and regionally selective, delayed BBB openings were also seen, but recovery was not evident in cerebral regions at 24 h. Cortex exhibited a large increase in Ki indicating that a delayed, marked deterioration of BBB integrity had developed between the 6 h and 24 h time points. It is concluded that the combination of transfer constant measurements and the 2-vessel occlusion model could provide a sensitive means for investigating the cerebrovascular consequences and therapy of stroke.

Animals↗
PubMed1990

The beta-tubulin gene family in Zea mays: two differentially expressed beta-tubulin genes.

Maize beta-tubulins are encoded by a large multigene family with at least nine members, as determined by Southern blot analysis. Two expressed genes, represented by the beta 1 genomic clone and the beta 2 cDNA clone, were examined in this study. The two genes encode beta-tubulins which show 94% sequence identity at the amino acid level. Maize beta 1 transcript levels were highest in seedling root tip and tissue culture cells, which are both rapidly dividing tissues. No transcripts were detected in non-dividing leaf tissue. In contrast, beta 2 transcripts were present at relatively high levels in tissue culture cells and at lower levels in seedling root tip and leaf tissue. The electrophoretic mobility of the beta 2 polypeptide was examined in relation to the constellation of beta-tubulin polypeptides on two-dimensional gel western blots of a maize pollen total protein extract. No evidence for post-translational modification of the beta-tubulin polypeptides was found in pollen.

Base Sequence↗
PubMed1990

Ambient temperature modulation of fenfluramine-induced thermogenesis in the rat.

The anti-obesity drug fenfluramine, promotes loss of weight by reducing food intake; however, there is controversy as to whether the drug can also elevate expenditure of energy. Resting consumption of oxygen (VO2) was measured in conscious rats to determine whether the injection of fenfluramine increased metabolic rate and whether prior fasting, or ambient temperature altered the response. Regardless of whether the rats were fed or had been fasted for 22 hr, in a thermoneutral environment (28 degrees C), the intraperitoneal injection of dl-fenfluramine (20 mg/kg) caused a raised oxygen consumption. This elevation was sustained to the end of the 60-min period of measurement after the injection, at which point the colonic temperature was found to be increased. This metabolic response to fenfluramine was largely attenuated when the drug was administered at 23 degrees C, and the colonic temperature of the rats was decreased by 60 min after the injection. At 4 degrees C, the injection of fenfluramine inhibited thermogenesis against cold, the oxygen consumption fell and the rats exhibited hypothermia. It was concluded that fenfluramine can increase the metabolic rate, but that this effect is not conditional on associated food intake, as has been reported. Rather, the ambient temperature governs whether stimulation or inhibition of thermogenesis will be evoked. These metabolic effects of fenfluramine explain, in part, its divergent effects on body temperature, reported previously.

Anesthesia↗