Biomedical subjects

A Platz

Publications and source records attributed to A Platz.

At least 37 records · Page 2Linked to original sources

PubMed2000

[A typical snowboarding injury--fracture of the processus lateralis tali].

Before the development of the snowboard sport, the fracture of the lateral process of the talus was a very rare injury. Since the increasing popularity of snowboarding, starting in Europe at about 1980, these fractures occurred more frequently. The largest epidemiological serie from Kirkpatrick in 1998 reports an incidence of 2.3% of all snowboarding injuries representing 15% of all snowboarding ankle injuries [1]. The common mechanism for fracture is dorsiflexion of the ankle and inversion of the hindfoot. Early diagnosis is emphasized in all series reviewed in the literature to prevent long-term complications [4]. Because routine radiographs failed to determine either the size or comminution of the fractured process, CT imaging was used to accurately assess the size, displacement, and comminution of the fractured process. CT scans also showed the extent of subtalar joint involvement, any associated tendon pathology, or additional fractures [5]. Many of these fractures are not visible on plain radiographs and require computed tomography imaging to be diagnosed. Diagnosis of this fracture pattern is paramount; the physician should be very suspicious of anterolateral ankle pain in the snowboarder, where subtle fractures that may require surgical intervention can be confused with anterior talofibular ligament sprains [1]. Most authors agree, that nondisplaced fractures are best treated with cast immobilization and that displaced fractures require a surgical treatment: Single large displaced fragments are reduced and internally fixed, small displaced or comminuted fragments may need surgical excision. After two to three days bedrest with elevated leg, ambulation is started under partial weight bearing of 10-15 kg for 6 weeks. Physicians caring for snowboarders should look specifically for fracture of the lateral process of the talus in a snowboarder with a lateral ankle or foot injury [3]. This fracture can mimic a lateral ankle sprain, yet the fracture is easily missed on plain radiographs of the ankle. Because displaced or comminuted fractures can cause long-term disability, primary care physicians and specialists alike need to be aware of the association of this fracture with snowboarding [3].

Athletic Injuries↗

PubMed2000

Incidence and clinical pattern of the abdominal compartment syndrome after "damage-control" laparotomy in 311 patients with severe abdominal and/or pelvic trauma.

OBJECTIVE: To investigate the incidence, main physiologic effects, and therapeutic management of the abdominal compartment syndrome (ACS) after severe abdominal and/or pelvic trauma. DESIGN: Retrospective analysis from January 1991 to December 1996; prospective study from January 1997 to August 1998. SETTING: Level I trauma center, intensive care unit. PATIENTS: A total of 311 patients with severe abdominal and/or pelvic trauma and "damage-control" laparotomy on day of admission. INTERVENTIONS: The ACS was defined as the development of significant respiratory compromise, including elevated inspiratory pressure of >35 mbar, a decreased Horowitz quotient (<150 torr [<20 kPa]), renal dysfunction (urine output, <30 mL/hr), hemodynamic instability necessitating catecholamines, and a rigid or tense abdomen. Beginning with January 1997, urinary bladder pressure as an additional variable for the diagnosis of ACS was continuously measured in patients (n = 12) at risk. Bladder pressures of >25 mm Hg indicated ACS. MEASUREMENTS AND MAIN RESULTS: Seventeen patients (5.5%) developed ACS because of persistent intra-abdominal/retroperitoneal bleeding (n = 12; 70.6%) or visceral edema (n = 5; 29.4%). All patients with ACS underwent primary fascial closure. In eight of these patients (47%), abdominal and/or pelvic packing for hemostasis was performed. All patients with ACS required decompressive emergency laparotomies because of physiologic derangements. The time between primary laparotomy and decompressive laparotomy was 12.9 +/- 2.0 hrs. Emergency decompression of the abdomen resulted in a significant increase in the cardiac index (+146%), tidal volume (+133%), Horowitz quotient (+156%), and urine output (+1557%), whereas bladder pressure (-63%), heart rate (-19%), central venous pressure (-30%), pulmonary artery occlusion pressure (-43%), peak airway pressure (-31%), partial pressure arterial carbon dioxide (-30%), and lactate (-40%) markedly (p < .05) decreased. In two multiply injured patients with additional head trauma, ACS caused a critical increase of the intracranial pressure, which markedly dropped after the release of abdominal tension. CONCLUSIONS: Risk factors for the occurrence of ACS are severe abdominal and/or pelvic trauma, which require laparotomy and packing for the control of hemorrhage. The ACS occurs within hours and causes life-threatening physiologic derangements and a critical rise in intracranial pressure in patients with combined abdominal/pelvic and head trauma. Decompressive laparotomy immediately restores impaired organ functions. In patients at risk, the continuous measurement of urinary bladder pressure as a simple, noninvasive, and less expensive diagnostic tool for early detection of elevated intra-abdominal pressure is mandatory.

Abdomen↗

PubMed1999

Endocytosis of heparin-binding protein (CAP37) is essential for the enhancement of lipopolysaccharide-induced TNF-alpha production in human monocytes.

Heparin-binding protein (HBP), also known as CAP37, is a proteolytically inactive serine protease homologue that is released from activated granulocytes. However, HBP is not a biologically inactive molecule but rather a multifunctional protein with properties that include the enhancement of LPS-induced TNF-alpha production from monocytes. We have previously demonstrated that HBP is internalized in monocytes. In the current study, we hypothesize that HBP is internalized in monocytes via endocytosis, and this internalization is an important mechanism by which HBP enhances LPS-induced TNF-alpha release. Using whole blood from healthy donors and flow cytometry, we found that colchicine (0.1-10 mM), cytochalasin D (1000 microM), NH4Cl (10-50 mM), and bafilomycin A1 (0.1-3 microM) significantly reduced the affinity of FITC-HBP for CD14-positive monocytes. Using isolated human monocytes and ELISA, we found that colchicine (0.1 mM), cytochalasin D (30 and 300 microM), NH4Cl (30 mM), and bafilomycin A1 (1 microM) significantly reduced the effect of HBP (10 microg/ml) to enhance LPS (10 ng/ml)-induced TNF-alpha release after 24 h. These findings demonstrate that internalization of HBP in monocytes is essential for the enhancement of LPS-induced TNF-alpha release. Transport of HBP to an activating compartment depends on intact F-actin polymerization and endosomal acidification, an important mechanism for endosomal protein sorting and trafficking.

Adjuvants, Immunologic↗

PubMed1999

[Combined surgery for fractures of the thoraco-lumbar junction using the inlay-span method].

The combined intervention of thoracolumbar fractures using the graft inlay technique. Instable fractures of the thoracolumbar junction must be reduced in an open or closed fashion and fixed internally. Clearance of the spinal channel in case of obstruction is mandatory followed by reconstruction of the anterior part of the spine. Using the combined interventions of transpedicular screw techniques and antero-lateral approaches (transthoracal or retroperitoneal) instable fractures of the thoracolumbar junction can be fixed in comparison to the dorsal intervention the anterior approach is very demanding. The proximity of the big vessels as well as thoracal and abdominal organs and the available space to place the implants need exact preoperative planning. The indications for reconstruction of the anterior part of the spine are influenced by the fracture types and localisations as well as biomechanical considerations. One of the many possibilities to reconstruct the anterior part of the spine is the graft inlay technique, which can be used for mono- or bisegmental spondylodesis. Despite the biological advantages in terms of fusion rates substantial complications can occur using this method for anterior reconstruction of the spine.

Bone Plates↗

PubMed1999

[Duodenal injuries in abdominal trauma].

BACKGROUND: We retrospectively reviewed our patients between 1988 and 1996 with duodenal injuries to demonstrate the diagnostic and therapeutic management. MATERIAL AND METHODS: The charts of six patients treated in the Division of Traumatology of the University Hospital of Zurich between 1988 and 1996 have been retrospectively reviewed. The mean age was 25 years. In four patients a blunt trauma and in two patients a two gunshot caused the duodenal injury. The injury was classified with the "Duodenum Organ Injury Scale". RESULTS: The primary repair was successful in three patients, twice a Roux-en-Y duodenojejunostomy with repair of the biliary tract was performed and once a conservative treatment was chosen. No surgery related complications occurred. Two patients died postoperatively because of associated injuries. CONCLUSIONS: Duodenal injuries are rare and therefore correct diagnosis and treatment is difficult. In case of penetrating trauma or hemodynamic instable patients following blunt trauma the emergent laparotomy is mandatory. CT scan is recommended in cases of hemodynamic stable patients after blunt trauma. Primary repair is the treatment of choice in the majority of duodenal injuries.

Abdominal Injuries↗

PubMed1999

Heparin and enoxaparin enhance endotoxin-induced tumor necrosis factor-alpha production in human monocytes.

OBJECTIVE: To determine whether heparin or the low-molecular-weight heparin enoxaparin alter lipopolysaccharide (LPS)-induced monocyte activation. SUMMARY BACKGROUND DATA: Heparin is widely used in clinical practice to inhibit the coagulation cascade. However, heparin also is a naturally occurring glucosaminoglycan and a pleiotropic immunomodulator that binds to a variety of proteins. LPS is a component of gram-negative bacteria and is thought to be responsible for many of the deleterious effects seen in sepsis. The binding of LPS to CD14 induces a signaling cascade that results in the release of many inflammatory mediators, including tumor necrosis factor-alpha (TNF-alpha). METHODS: Monocytes from healthy volunteers were isolated and cultured in the presence of saline, LPS (10 ng/ml), heparin (0.1 to 1000 microg/ml), or enoxaparin (0.1 to 1000 microg/ml). In blocking experiments, cells were pretreated for 60 minutes with the monoclonal anti-CD14 antibody MY4 (10 microg/ml) or with isotype-matched control IgG2 (10 microg/ml). TNF-alpha values were measured with enzyme-linked immunosorbent assay. Significance was assessed with analysis of variance. RESULTS: Heparin (10 to 1000 microg/ml) and enoxaparin (1000 microg/ml) significantly enhanced LPS-induced TNF-alpha release. Heparin (1000 microg/ml) or enoxaparin (1000 microg/ml) did not produce TNF-alpha in the absence of LPS. Blockade of CD14 abrogated both LPS-induced TNF-alpha release and the effect of heparin or enoxaparin to enhance LPS-induced TNF-alpha release. CONCLUSIONS: The effect of heparin to enhance LPS-induced TNF-alpha release is a biologic phenomenon that reveals a novel and potentially important host defense mechanism during endotoxemia and sepsis. Binding of LPS to CD14 is necessary to induce this phenomenon, suggesting that both heparin and enoxaparin induce signaling mechanisms that are downstream from the initial binding of LPS on CD14.

Anticoagulants↗

PubMed1999

Posterior elbow dislocation with associated vascular injury after blunt trauma.

BACKGROUND: Injury of the brachial artery is a rare (5-13%) but serious complication after closed elbow dislocation without associated fractures. METHOD: Retrospective analysis of long-term results (mean, 4.1 years) in four patients. RESULTS: All patients underwent emergency repair of the arterial injury within 2.5 hours. In three patients, a reversed saphenous vein graft was used; in one patient the artery was sutured. This latter patient needed another operation with interposition of a reversed saphenous graft, because the primary anastomosis occluded. The capsule and the collateral ligaments were immediately reconstructed in three patients because of instability. No patient showed claudication of the arm. In three patients, a sensory deficiency of median nerve persisted. Average range of motion was 128 degrees of flexion (120-135 degrees) and an extension deficit of 7.5 degrees (15-0 degrees). CONCLUSION: Primary repair of vascular injury after closed elbow dislocation with vein graft and immediate reconstruction of ligamentous injuries results in good long-term functional outcome.

Adult↗

PubMed1999

Internal fixation of distal radius fractures with dorsal dislocation: pi-plate or two 1/4 tube plates? A prospective randomized study.

BACKGROUND: Severely comminuted distal radius fractures can be treated by different methods. Our routine procedure in dorsal dislocated fractures is the dorsal stabilization with two 1/4 tube plates. The new pi-plate is an other device that matches optimally the anatomy of the distal radius and allows a near half-circumferential dorsal buttress of comminuted intraarticular and extra-articular radial fractures. METHODS: In a prospective randomized study, comminuted distal radius fractures with dorsal displacement were stabilized either with two 1/4 tube plates or with the pi-plate. All patients were reviewed at 1, 3, and 6 months after surgery by thorough clinical examination and standard radiographs of both wrists. Results were analyzed and compared in both groups. RESULTS: Subjective and objective results in the pi-plate group are disappointing. Although optimal anatomic results were achieved, the complication-rate was high (14.3%) and the range of motion was limited. At final review, extension and flexion of the injured wrist had recovered to an average of 67% of the normal, contralateral side. Radial and ulnar deviation were limited to 64%, whereas pronation and supination reached 89% and 87%, respectively. Overall, results were good to excellent only in 56%. In a comparable group of patients with similar fractures and stabilization with two 1/4 tube plates, 82% of patients achieved excellent to good results, wrist motion was significantly better (p < 0.05), and no complications occurred. CONCLUSION: With open reduction, cancellous bone grafting, and internal plate fixation in comminuted distal radial fractures, excellent results can be achieved. In our experience, we cannot recommend the 7pi-plate in its current shape and prefer to stabilize distal radius fractures and dorsal fragment dislocations with two 1/4 tube plates.

Adolescent↗

PubMed1999

Melanoma development in relation to non-functional p16/INK4A protein and dysplastic naevus syndrome in Swedish melanoma kindreds.

The CDKN2A gene encodes the cell cycle inhibitor p16/ INK4A, which is involved in familial cutaneous melanoma. We have studied five Swedish familial melanoma kindreds characterized by germline mutations in CDKN2A and dysplastic naevus syndrome (DNS). We found significant correlations between germline CDKN2A mutations and melanoma and between DNS phenotype and melanoma, respectively. There was also a correlation between mutation status and the presence of DNS. In CDKN2A mutation carriers, all cases of early-onset melanoma occurred in DNS individuals, and the mean age at melanoma diagnosis was significantly lower in individuals with DNS than in those without a confirmed DNS phenotype. In one family where the proband had a P48L mutation in CDKN2A exon 1, the DNS phenotype was studied in detail. In vitro binding experiments established that the P48L mutant protein does not bind to cdk4 or cdk6 and thus is functionally abnormal. Furthermore, we demonstrated loss of heterozygosity at markers on chromosome 9p flanking the CDKN2A locus in a primary melanoma and a metastasis from the proband. Our results are consistent with the hypothesis that germline CDKN2A mutations and DNS both contribute to the predisposition to melanoma and may lead to the development of early-onset melanoma when present in the same individual.

Chromosomes, Human, Pair 9↗

PubMed1999

[Role of laparoscopy in the management of acute appendicitis].

Minimal invasive surgery had a considerable impact on common surgical techniques and has almost replaced established operative procedures such as cholecystectomy. However, the laparoscopic approach for the treatment of acute appendicitis is still not very popular. We discuss the role of laparoscopy for appendectomy and include three studies from our institution (University Hospital Zürich, Switzerland) and prospective studies reported in the literature. We conclude that laparoscopic appendectomy, when compared with the open approach, has the following advantages for the diagnosis and treatment of acute appendicitis. (1) Diagnostic laparoscopy is an effective and relatively atraumatic tool to investigate the abdominal cavity, which results in a sensitivity of almost 100%. This allows for accurate decision making, which is especially advantageous in young women and obese patients. (2) Prospective studies demonstrate that laparoscopic appendectomy is at least as good as open appendectomy and that the laparoscopic approach results in a reduced postoperative infection rate. (3) The similar complication rate after laparoscopic appendectomy, when performed by residents rather than staff surgeons, underlines the feasibility and teaching potential of this minimal invasive procedure.

Acute Disease↗

PubMed1998

Screening of germline mutations in the CDK4, CDKN2C and TP53 genes in familial melanoma: a clinic-based population study.

Germline mutations within the CDKN2A gene, coding for the cyclin-dependent kinase inhibitor p16, have been detected by screening in 8% of Swedish families with an inheritance of cutaneous melanoma (FMM) and dysplastic nevus syndrome (DNS). Contrastingly, the closely related gene CDKN2B had no disease-related mutations in these families. A majority of Swedish families with hereditary melanoma predisposition thus lack germline mutations in these cell cycle G1 checkpoint-regulating genes. Additional genes with the potential to contribute to increased melanoma risk may code for related components of the cell cycle-regulating machinery. The gene for cyclin-dependent kinase 4, CDK4, has been found in mutated form in the germline from individuals belonging to 2 melanoma kindreds in the United States. The CDKN2C gene coding for the cyclin-dependent kinase inhibitor p18 is localized on 1p32, a region frequently involved in chromosomal changes in melanomas and other tumors. The TP53 suppressor gene, involved in cell cycle regulation and maintenance of genetic stability, is found mutated in the germline of patients with hereditary Li-Fraumeni syndrome, leading to early onset of several human cancers, including melanoma. The present investigation reports the results of screening the 100 Swedish melanoma families for germline mutations in the CDK4, CDKN2C and TP53 genes. No disease-related mutations were detected in the coding regions. A direct contribution of these genes to the hereditary risk for melanoma in members of Swedish melanoma kindreds therefore appears unlikely.

Base Sequence↗

PubMed1998

Detection of mutations in GC-rich DNA by bisulphite denaturing gradient gel electrophoresis.

Denaturing gradient gel electrophoresis (DGGE) in combination with PCR and 'GC-clamping' has proven highly efficient as a method for detection of DNA sequence differences. Due to strand dissociation phenomena, however, its use has been limited to the analysis of sequences with a relatively low content of GC pairs. This paper describes how treatment of template DNA with sodium bisulphite drastically lowers the melting temperature of very GC-rich sequences and renders them amenable to DGGE analysis. We demonstrate the use of bisulphite DGGE for rapid and efficient detection of mutations in the p16(INK4/CDKN2) tumour suppressor gene.

Base Composition↗

PubMed1998

Diagnostic value of duplex ultrasound and liquid crystal contact thermography in preclinical detection of deep vein thrombosis after proximal femur fractures.

During a prospective clinical study the diagnostic value of the two non-invasive examinations colour-coded duplex ultrasound (Duplex) and fluid crystal contact thermography (LCCT) was investigated in relation to phlebography, the standard examination for the diagnosis of deep vein thrombosis (DVT), in 112 patients with proximal femur fractures. In 19% of the patients, DVT was diagnosed by phlebography, with the main localisation in the lower leg in 19 of 21 (90%) thromboses. With a negative prediction value of 83%, Duplex is less suitable than LCCT under such difficult examination conditions as the early postoperative period. The specificity of Duplex is 95%, but the sensitivity only 18%. The specificity of LCCT is 85% and the sensitivity 75%. Considering the frequency of postoperative DVT after surgery on the legs, especially hip surgery, a postoperative screening for DVT should become mandatory. LCCT has proved to be a suitable, cheap, non-invasive examination with a negative prediction value of 94%.

Adult↗

PubMed1998

Heparin binding protein (CAP37) is an opsonin for Staphylococcus aureus and increases phagocytosis in monocytes.

Heparin binding protein (HBP), also known as cationic antibiotic protein (CAP37) or azurocidin, is stored in azurophilic granules of neutrophils and is released to the extracellular space when granulocytes phagocytose Staphylococcus aureus. We investigated whether extracellular HBP also has the potential to increase phagocytosis of S. aureus by other phagocytes. We used flow cytometry to characterize the binding of HBP to S. aureus and to simultaneously measure phagocytosis and superoxide production of opsonized S. aureus in monocytes and granulocytes. Our results demonstrate that HBP is a strong opsonin for S. aureus, and that monocytes, but not granulocytes, increase phagocytosis of HBP-treated S. aureus. However, HBP-treated S. aureus increases the production of superoxide in both monocytes and granulocytes as compared with untreated S. aureus. These findings support the role of granulocytes in the afferent limb of inflammation and demonstrate that HBP, when released from activated granulocytes, potentiates bacterial uptake in monocytes and enhances the potential of microbial killing in monocytes and granulocytes.

Antimicrobial Cationic Peptides↗

PubMed1998

Non-operative management of blunt hepatic trauma.

BACKGROUND: Non-operative management is currently considered the treatment of choice in over 50 per cent of adult patients with blunt liver injury. This report reviews the criteria for non-operative management and its potential downside. METHODS: English language publications were reviewed. RESULTS: Most reports from major trauma centres in the USA support the non-operative treatment of patients with blunt liver injury if well established criteria are met. Using such criteria, non-operative treatment is successful in 50-80 per cent of cases. Adjunctive radiological techniques may be helpful in managing some complications of non-operative treatment. CONCLUSION: Non-operative management is safe in haemodynamically stable patients with blunt liver injury. Computed tomography (CT) of the abdomen is extremely useful to document the extent of the damage and the presence of associated injuries, but it is not possible, based on CT alone, to predict failure; careful physiological monitoring in selected patients is indicated to avoid catastrophic complications.

Adult↗

PubMed1998

N-ras mutations are common in melanomas from sun-exposed skin of humans but rare in mucosal membranes or unexposed skin.

Ras mutations, preferentially in codon 61 of the N-ras oncogene, are common in human cutaneous melanomas. In this study, we questioned the association between ras mutations in primary melanomas and sun exposure. DNA was extracted from formalin-fixed primary melanomas: 28 at chronically sun-exposed head and neck areas, 18 at sites subject to intermittent sun exposure, and 28 from unexposed mucosal membranes (vulva/vagina, anus/ rectum, palate). Mutations of both exons of H-, K-, and N-ras genes were examined by polymerase chain reaction/single-strand conformation polymorphism and by direct nucleotide sequencing of the polymerase chain reaction amplified exons. Thirty-two per cent of the head and neck melanomas and 11% of the melanomas from intermittently sun-exposed skin had N-ras codon 61 mutations; comparatively only 7% of the tumors from the unexposed areas had such mutations. One vulvar melanoma had an N-ras codon 12 mutation. No H-ras or K-ras mutations were detected in any sample. The frequency of N-ras exon 2 mutations in melanomas of typically sunbathed skin was compared for the first time with that in melanomas of areas completely protected from sun exposure. The significantly higher frequency (p = 0.04, chi square exact test) of these N-ras mutations on the head and neck demonstrates their UV-light induction in a subset of melanomas explaining one of the molecular effects of UV light in human skin.

Base Sequence↗

PubMed1998

[Diagnosis and therapy of vascular injuries in posterior knee dislocation].

AIM: We demonstrate the management and treatment of dislocation of the knee associated with vascular injury. The goal of the treatment is to avoid complications due to ischemia. The injured vessel can be repaired either by direct suture or by interposition of a saphenous vein graft. Capsule and ligaments should be reconstructed secondarily. PATIENTS AND METHODS: The charts of ten patients treated in the Division of Traumatology of the University of Zurich between 1979 and 1996 have been retrospectively checked. RESULTS: In eight of ten patients the injured vessel has been reconstructed with a saphenous vein graft, in one patient the artery has been repaired by direct suture. In one patient a flap of the intima has been refixed by endarterectomy. In five patients the knee has been stabilised with a transfixation (external fixation). In two patients the ligaments and the capsule were reconstructed at the time of vascular repair, in seven patients the reconstruction has been performed secondary. CONCLUSIONS: In case of a dislocation of the knee the examination of the vessels is mandatory. In case of a critical perfusion the "on table"--angiography is the procedure of choice. As an alternative method duplex sonography has been established. The vascular reconstruction is performed by saphenous vein graft interposition. We recommend to reconstruct ligamentous and capsular structures secondary.

Adult↗

PubMed1998

[Response of osteoblast cultures to titanium, steel and hydroxyapatite implants].

The biocompatibility of bone implants and substitutes is usually tested on cell-lines only, despite a different and more relevant behaviour on primary osteoblasts as final targets can be expected. "Osteoblast-like" cell line (MC3T3-E1) and fresh human osteoblasts (HOB), cultured from cancellous bone grafts from the iliac crest were used for the study. Three different clinically used biomaterials were compared regarding biocompatibility: titanium, steel and hydroxyapatite (Bio-Oss). "Osteoblast-like" cell line and fresh human osteoblasts (5x104) were seeded on the three bone implants. Cell proliferation and osteocalcin synthesis were determined 1, 3, 7, and 10 days after the cells were plated on the biomaterials. All experiments were performed in five times (pro culture double measurements). HOB proliferation on hydroxyapatite was decreasing after 3 days, whereas cells from "Osteoblast-like" cell line showed comparable proliferation to the control group. The most interesting observation was the significant decrease of the osteocalcin levels (in conditioned medium) of "osteoblast like" cells and HOB on HA (Bio-Oss). We conclude that HA disturbs the proliferation and osteocalcin synthesis of HOB.

Bone Substitutes↗