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P Klein

Publications and source records attributed to P Klein.

At least 19 recordsLinked to original sources
PubMed2005

Isolated central nervous system metastases in patients with HER2-overexpressing advanced breast cancer treated with first-line trastuzumab-based therapy.

PURPOSE: The aim of this study was to characterize the prevalence and predictors of central nervous system (CNS) metastasis among women with HER2-overexpressing metastatic breast cancer receiving trastuzumab-based therapy. METHODS: The frequency and time course of isolated CNS progression were characterized among women with HER2-positive metastatic breast cancer, receiving chemotherapy with or without trastuzumab as first-line treatment for metastatic disease in two clinical trials. The first trial was a multicenter randomized phase III study of chemotherapy (doxorubicin/cyclophosphamide or paclitaxel) +/- trastuzumab, and the second was a multicenter phase II trial of vinorelbine + trastuzumab. All patients had measurable disease and were free of symptomatic CNS disease at initiation of study treatment. RESULTS: Nearly 10% of patients receiving trastuzumab in combination with chemotherapy developed isolated CNS metastases as first site of tumor progression. Progression in the CNS tended to be a later event than progression at other sites among women receiving trastuzumab-based therapy. Trastuzumab-based treatment did not substantially delay onset of CNS metastases as initial site of progression. Following diagnosis with primary breast cancer, tumors with HER2 gene amplification tend to be associated with greater risk of isolated CNS progression compared with those lacking gene amplification. CONCLUSIONS: Patients with HER2-overexpressing metastatic breast cancer are at risk for isolated CNS progression, reflecting improved peripheral tumor control and patient survival through use of trastuzumab-based therapy, and a relative lack of CNS activity with trastuzumab. Clinicians should be aware of this association. Better treatments for CNS recurrences are needed.

Antibodies, Monoclonal↗
PubMed2005

Poly(D,L-lactide) coating is capable of enhancing osseous integration of Schanz screws in the absence of infection.

Pin loosening is a major complication in external fixation. Biological and mechanical conditions play an important role in the maintenance and enhancement of the implant-bone interface in fracture fixation. It is thought that biodegradable coatings may be capable of preventing pin track infection and pin loosening. The goal of this study was therefore to analyze the influence of a biodegradeable coating on the osseous integration of Schanz' screws during fracture treatment. Standardized osteotomies (3-mm fracture gap) of the right tibiae were performed on 16 sheep and stabilized by an AO mono-lateral external fixator. Additional, mechanically less loaded Schanz' screws were also mounted. All screws were randomly coated with biodegradable poly(D,L-lactide). The sheep were sacrificed after 9 weeks. All screws were removed and rolled on blood agar plates for microbiological analysis. Histological sections of the pin tracks were histochemically and morphometrically analyzed. Clinically, no signs of severe infection were visible. Microbiological analysis revealed 14.8% colonization by Staphylococcus aureus in the coated and 29% in the uncoated screws. Histomorphometry of the bone surrounding the Schanz' screws revealed that significantly more osseous integration had occurred on poly(D,L-lactide)-coated screws in the absence of bacterial colonization. Significantly more bone remodeling and a higher osteoclastic activity was seen near the screw-bone interface in the uncoated screw group. Up to a threefold increase in new bone formation and more severe remodeling was observed around the screw entry compared to the pin exit in all groups. Loaded screws showed significantly more callus formation around the exit sites than their less loaded counterparts. In the present study, poly(D,L-lactide) coating of Schanz' screws was found to enhance osseous integration in the absence of bacterial colonization in sheep by causing less cortical remodeling and less osteoclastic activity in the cortices compared to uncoated screws. Additionally, the coating appeared to reduce the instances of pin track infections. Mechanical loading showed an adverse effect on bone formation and remodeling. It has been shown that both biological and mechanical factors play an important role in the maintenance of osseous integrity of the pin-bone interface. Poly(D,L-lactide) coating of Schanz' screws does not prevent osseous destruction and severe bacterial colonization along the pin tracts, but can improve osseous integration of Schanz' screws in the absence of infection.

Agar↗
PubMed2004

Are bone turnover markers capable of predicting callus consolidation during bone healing?

The aim of this study was to determine the ability of the following bone turnover markers to monitor the course of callus consolidation during bone healing: Carboxy-terminal propeptide of procollagen type I (PICP), skeletal alkaline phosphatase (sALP), and amino-terminal propeptide of type III procollagen (PIlINP). Since interfragmentary movements have been proven to possess the ability to document the progression of bone healing in experimental studies, correlations between bone turnover markers and interfragmentary movements in vivo were investigated. Therefore, two different types of osteosyntheses representing different mechanical situations at the fracture site were compared in an ovine osteotomy model. Blood samples were taken preoperatively and postoperatively in weekly intervals over a nine-week healing period. At the same intervals, interfragmentary movements were measured in all sheep. After nine weeks, animals were sacrificed and the tibiae were evaluated both mechanically and histologically. Wide interindividual ranges were observed for all bone turnover markers. The systemic PICP level did not increase with callus consolidation. The bone-healing model seemed to influence the systemic level of PIIINP and sALP but no general correlation between bone turnover markers and interfragmentary movements could be detected. No differences between the different types of osteosyntheses and thus the different mechanical situations were observed. All analyzed markers failed as general predictors for the course of callus consolidation during bone healing.

Alkaline Phosphatase↗
PubMed2004

Comparison of unreamed nailing and external fixation of tibial diastases--mechanical conditions during healing and biological outcome.

Locked intramedullary nailing and external fixation are alternatives for the stabilization of tibial shaft fractures. The goal of this study was to determine to what extent the mechanical conditions at the fracture site influence the healing process after unreamed tibial nailing compared to external fixation. A standardized tibial diastasis was stabilized with either a locked unreamed tibial nail or a monolateral fixator in a sheep model. Interfragmentary movements and ground reaction parameters were monitored in vivo throughout the healing period. After sacrifice, the tibiae were examined mechanically and histologically. Bending angles and axial torsion at the fracture site were larger in the nail group within the first five weeks post-operatively. Unlike the fixator group, the operated limb in the nail group did not return to full weight bearing during the treatment period. Mechanical and histomorphometrical observations showed significantly inferior bone healing in the nail group compared to the fixator group. In this study, unreamed nailing of a tibial diastasis did not provide rotational stability of the osteosynthesis and resulted in a significant delay in bone healing.

Animals↗
PubMed2004

Inter- and intraexaminer reliability in palpation of the "primary respiratory mechanism" within the "cranial concept".

Inevitable subjectivity makes interexaminer reliability of manual assessment procedures a special matter of concern. The cranial concept (CC), one aspect of osteopathy, deals with very subtle changes that have to be palpated. One of the main principles of the CC is the primary respiratory mechanism (PRM), which is hypothesized to be a palpable physiological phenomenon that occurs in rhythmic cycles, called flexion- and extension-phase, which are independent from cardiac and respiratory rates. Palpation of the PRM is one of the first steps in assessment within the CC. An inter- and intraexaminer reliability study design for repeated measures was used in this study. Forty nine healthy subjects were palpated simultaneously twice, once at the head and once at the pelvis. PRM-frequency (f), the mean duration of the flexion phase and the mean ratio of flexion- to extension-phase were used as the main outcome measures. Inter- and intraexaminer reliability and correlations to the respiratory rates were analysed for all three parameters. Inter- as well as intraexaminer agreement could not be described beyond chance agreement, as the range within the 95% limits of agreement (e.g. for f=6.6 cycles/90 s) for all cases resembled the total range of values (e.g. for f=7 cycles/90 s) that were produced. A significant effect of the examiners' respiration was found for both examiners at the pelvis (P=0.004 for one examiner, P <0.0001 for the other examiner), and for one examiner only at the head (P=0.0017). No correlation could be found for the subjects' respiratory rates. In conclusion, PRM-rates could not be palpated reliably and under certain conditions were influenced by the examiners' respiratory rates. These results do not support the hypotheses behind the PRM. The role of PRM palpation for clinical decision making and the models explaining the PRM should therefore be rethought.

Adult↗
PubMed2004

Treatment of muscle injuries by local administration of autologous conditioned serum: a pilot study on sportsmen with muscle strains.

Muscle injuries represent a major part of sports injuries and are a challenging problem in traumatology. Strain injuries are the most common muscle injuries after contusions. These injuries can lead to significant pain and disability causing time to be lost to training and competition. Despite the frequency of strain injuries the treatment available is limited and is generally not sufficient to enhance muscle regeneration efficiently when fast resumption of sport activity is a primary target. A number of growth factors play a specific role in regeneration and it has been proven that a previously described method of physically and chemically stimulating whole blood (to produce autologous conditioned serum) induces concentration increases in FGF-2, HGF, and TGF-beta1. A preliminary study was conducted on muscle strain injuries in professional sportsmen receiving either: 1. autologous conditioned serum (ACS) or 2. Actovegin/Traumeel treatment as control. Assessment of recovery from injury was done by: 1. sport professional's ability to participate to 100 % under competition conditions in their respective sport and 2. MRI analysis. A significant difference in the recovery time from injury was demonstrated: 16.6 +/- 0.9 in the ACS treated instead of 22.3 +/- 1.2 (mean +/- SEM) days in the Actovegin/Traumeel control group (p = 0.001). MRI analysis supported the observed acceleration of the lesion recovery time. We conclude that ACS injection is a promising approach to reduce the time to recovery from muscle injury.

Athletic Injuries↗
PubMed2004

Effectiveness and tolerability of a homoeopathic remedy compared with conventional therapy for mild viral infections.

Treatments for mild viral infections are usually directed at providing symptomatic relief. The effectiveness of the homoeopathic remedy Gripp-Heel was compared with that of conventional treatments in a prospective, observational cohort study in 485 patients with mild viral infections and symptoms such as fever, headache, muscle pain, cough or sore throat. Practitioners specialised in homoeopathy or conventional treatment, or practised both to similar extents. As evaluated by the practitioners, the homoeopathic therapy was effective to similar or greater degree than the conventional therapies: 67.9% of patients were considered asymptomatic at the end of Gripp-Heel therapy vs. 47.9% of patients in the control group. Practitioners judged homoeopathic treatments as 'successful' in 78.1% of cases vs. 52.2% for conventional therapies. Tolerability and compliance were good in both treatment groups, with the verdict 'very good' given for 88.9% of patients in the homoeopathic group vs. 38.8% in the conventional treatment group.

Acute Disease↗
PubMed2004

Amplified fragment length polymorphism reveals genomic variability among Mycobacterium avium subsp. paratuberculosis isolates.

Ninety-six primer sets were used for amplified fragment length polymorphism (AFLP) to characterize the genomes of 20 Mycobacterium avium subsp. paratuberculosis field isolates, 1 American Type Culture Collection (ATCC) M. avium subsp. paratuberculosis isolate (ATCC 19698), and 2 M. avium subsp. avium isolates (ATCC 35716 and Mac 104). AFLP analysis revealed a high degree of genomic polymorphism among M. avium subsp. paratuberculosis isolates that may be used to establish diagnostic patterns useful for the epidemiological tracking of M. avium subsp. paratuberculosis isolates. Four M. avium subsp. paratuberculosis-polymorphic regions revealed by AFLP were cloned and sequenced. Primers were generated internal to these regions for use in PCR analysis and applied to the M. avium subsp. paratuberculosis field isolates. An appropriate PCR product was obtained in 79 of 80 reactions, while the M. avium subsp. avium isolates failed to act as templates for PCR amplification in seven of eight reactions. This work revealed the presence of extensive polymorphisms in the genomes of M. avium subsp. paratuberculosis and M. avium subsp. avium, many of which are based on deletions. Of the M. avium subsp. paratuberculosis-specific sequences studied, one revealed a 5,145-bp region with no homologue in the M. avium subsp. avium genome. Within this region are genes responsible for integrase-recombinase function. Three additional M. avium subsp. paratuberculosis-polymorphic regions were cloned, revealing a number of housekeeping genes; all were evaluated for their diagnostic and epidemiological value.

Base Sequence↗
PubMed2003

Incisional hernia repair after orthotopic liver transplantation: a technique employing an inlay/onlay polypropylene mesh.

BACKGROUND: The literature provides no data on the incidence and operative management of incisional hernias developing after orthotopic liver transplantation. The use of high-dose immunosuppressive agents results in an appreciable delay in wound healing. There is thus a need for a procedure for the reconstruction of the abdominal wall for patients on immunosuppression. The aim of this retrospective study was to establish the incidence of incisional hernias and an analysis of the results after implantation of a polypropylene mesh in inlay-onlay technique after liver transplantation is given. METHODS: The basis for the present retrospective investigations was a total of 207 liver transplantations carried out in 192 patients (15 re-transplantations). After performing tensiometry, a polypropylene mesh (Marlex) was implanted to close the hernias using the inlay/onlay technique or a direct closure of the fascia was done. All treated hernias were followed up for a median of 18 months. RESULTS: Among 184 patients, 17 developed incisional hernias after primary direct closure of the abdominal wall, giving an incidence of 9%. In an additional 8 patients an incisional hernia was seen where an absorbable mesh was used to close the abdominal wall after liver transplantation. In addition, there were 25 incisional hernias after 207 liver transplantations (12%). One of 15 (7%) of the surgically repaired hernias with implantation of a polypropylene mesh (Marlex) developed a recurrence. All the 3 patients after direct apposition of the fascia without using a polypropylene mesh suffered a recurrence (3 of 3; 100%). Significant risk factors for developing an incisional hernia were the amount of ascites and the stay in the ICU after transplantation. Neither severe deep nor superficial wound infection nor bowel fistulas were observed after implantation of a inlay/onlay mesh. CONCLUSION: In patients after liver transplantation, the implantation of a polypropylene mesh proved to be an efficient and safe method of treating incisional hernias. Implantation of a mesh was not associated with an increased infection rate, despite the use of immunosuppression. In view of the high recurrence rate associated with primary closure, mesh implantation should be given preference.

Female↗
PubMed2003

Global 3D head-trunk kinematics during cervical spine manipulation at different levels.

OBJECTIVE: Determination of the three-dimensional kinematics of the head relative to the upper trunk obtained during a manipulation applied on two different cervical levels and on both sides. DESIGN: Descriptive study performed on 14 asymptomatic volunteers. The range of motion was measured by a 3D electrogoniometer during manipulation executed by the same practitioner. BACKGROUND: Spinal manipulative therapy is a common treatment approach in patients suffering from some spinal disorders. Complications exist; they are thought to be related to the force applied by the practitioner and the range of spinal motion obtained during the manipulation. Yet, little is known about cervical spine motion during manipulation. METHODS: Three dimensional electrogoniometry using a 6 degree-of-freedom spatial linkage fixed between the head and the upper trunk was used to record the pattern of motion and the amplitudes obtained during a manipulation on two cervical levels (C3 and C5) and on left and right sides. On single practitioner applied the same technique to all subjects in a seated position. RESULTS: The side and the spinal level manipulated did not influence 3D ranges of motion. The mean ranges of motion obtained were 30 degrees axial rotation, 46 degrees lateral bending and 2 degrees flexion. A significant difference of the flexion-extension range existed between manipulations with and without audible release. Axial rotation and lateral bending ranges were correlated. Except for lateral bending which was close to active range, the motion ranges obtained during manipulation were well below active range of motion reported in literature. CONCLUSIONS: The results of this study suggest that for the kind of manipulation applied, maximal amplitude between head and trunk does not exceed physiological active range of motion. The amplitude for rotation, which is generally assumed to involve greatest risks for negative side effects, is significantly lower than during active motion. As the study was performed with one practitioner, this result may only be generalized with care. RELEVANCE: In spinal manipulative therapy, extreme range of motion as the result of the forces applied is generally believed to represent a major risk for negative side effects, especially with regard to the cervical spine. With a multiple component technique, amplitudes between head and upper trunk were shown not to differ significantly with regard to the side nor to the spinal level. Recorded ranges of motion did not exceed those reported for active motion in literature.

Adult↗
PubMed2003

Efficacy of a homeopathic Crataegus preparation compared with usual therapy for mild (NYHA II) cardiac insufficiency: results of an observational cohort study.

OBJECTIVES: To compare the efficacy of the homeopathic Crataegus preparation Cralonin for non-inferiority to standard treatment for mild cardiac insufficiency. METHODS: Multicentre non-randomised cohort study in patients aged 50-75 years in New York Heart Association class II. Patients received Cralonin (n=110) or ACE inhibitor/diuretics (n=102) for 8 weeks. To adjust for confounding by baseline factors, populations were stratified according to propensity score. After adjusting, there were no statistically significant differences between treatment groups. Treatment efficacy was assessed on 15 variables. A stringent non-inferiority criterion for the upper limit of the 97.5% one-sided confidence interval of the treatment difference was set to 0.2x the standard deviation (S.D.). RESULTS: Both treatment regimens improved scores on most variables studied, with the greatest effect on double product after exercise (average score reduction 15.4% with Cralonin vs. 16.0% for the control group). Stringent non-inferiority of Cralonin was demonstrated on 7 variables. Medium-stringent (0.5xS.D.) non-inferiority was indicated by 13 variables (exceptions: systolic blood pressure (BP) during exercise and diastolic BP at rest; for these, differences between treatments were not significant). Both treatments were well tolerated. CONCLUSION: The Crataegus-based preparation Cralonin is non-inferior to usual ACE inhibitor/diuretics treatment for mild cardiac insufficiency on all parameters except BP reduction.

Aged↗
PubMed2003

Systemic application of growth hormone enhances the early healing phase of osteochondral defects--a preliminary study in micropigs.

Healing of osteochondral defects following trauma remains a significant clinical problem, often leading to osteoarthritis. Growth hormone (GH) has been shown to accelerate formation of bone and cartilage tissue in the growth plates and in cell cultures. To investigate the influence of systemically administered recombinant porcine growth hormone (r-pGH) on the healing of osteochondral defects we performed a histomorphometrical analysis of full-thickness cartilage defects in the femoral condyle of micropigs. Forty-eight mature female Yucatan micropigs were divided into two groups, one receiving a daily injection of r-pGH (100 microg/kg), the other receiving sodium chloride as placebo. A circular 6-mm-diameter full-thickness defect of the cartilage was created, extending 1.5 mm into the subchondral bone. The animals were sacrificed after 4 (n = 24) and 6 (n = 24) weeks. The von-Kossa stain was used to visualise the calcified structures; cartilage and the fibrous tissue were marked with a combined Safranin-O/light-green stain. The defect filling and the percentage of bone, cartilage, and fibrous tissue into the defect were evaluated using an image analysis system. Furthermore, histological grading was performed using the modified Wakitani score. After 4 weeks no differences were observed between both groups. The defect filling after 6 weeks with newly formed bone was significantly higher in the r-pGH-treated group. The formation of cartilage and fibrous tissue showed a trend towards better healing in the GH-treated group; however, there was no significant difference. In the r-pGH-treated group, the percentage of total defect filling was significantly higher. The evaluation of the vascularity showed a significantly lower number of vessels in the GH-treated group after 6 weeks. Histomorphological grading revealed a significantly lower total Wakitani score in the GH-treated group, which represents a better healing result compared to the controls. The results of the present study suggest that circulating r-pGH or one of its mediators may accelerate osteochondral defect healing by stimulating the formation of osseous and chondral tissue. The analysis of the vascularity leads to the assumption of an advanced maturation of the osteochondral defects under the influence of GH.

Actins↗
PubMed2002

[Immune tolerance and active suppression in oncology. Immunological principles and therapeutic options].

In view of the fact that conventional therapies continue to yield unsatisfactory results, a therapy based on tumor immunology is of increasing interest. The results of some clinical immunotherapy studies have shown that the mechanism of tolerance induced by tumors is of critical importance. There are several mechanisms to be recognized by the tumor, such asanergy, immunosuppressive cytokines, immunodeviation and dysfunction of the T-lymphocytes. The so-called tumor escape mechanisms, which often refer to molecules that contribute to the recognition of antigens and activation of specific T cells, also lead to immunological tolerance. Immunotherapies based on gene-modified tumor cells, peptide-pulsed antigen presenting cells (APC) or antibody therapies to activate immune cells, have a fairly reasonable chance of being successful if immunological tolerance can be understood and influenced. Time will show if combining all sorts of immunotherapy that are based on different strategies, can induce tumor rejection more efficiently. In the scope of multimodal therapy concepts, immunotherapy only seems to be reasonable if the immunological tolerance that was induced by tumors can be overcome. Immunological markers are of crucial importance, not only for the therapy but also for the diagnosis and prognosis of cancer patients.

Adjuvants, Immunologic↗
PubMed2002

Accuracy and precision of bone mineral density and bone mineral content in excised rat humeri using fan beam dual-energy X-ray absorptiometry.

The aim of this study was the evaluation of fan beam dual-energy X-ray absorptiometry (DXA) for measuring bone mineral density (BMD) and bone mineral content (BMC) of isolated rat humeri. Defleshed rat humeri from male Lewis rats were examined with a Hologic QDR 4500 A (Hologic, Inc., Bedford, MA) high-resolution densitometer both in water and 0.9% saline solution. The small animal scan protocol with the regional high-resolution mode was used. BMC measured by DXA was compared with bone dry weight, ash weight, and bone calcium content. Furthermore, DXA BMD and BMC precision were determined. We also evaluated the effect of salinity of the water bath in which the bones were measured. Correlations (r(2)) of BMC, as determined by DXA with dry weight, ash weight, and bone calcium content, were 0.978, 0.988, and 0.890, respectively. DXA overestimated ash weight by 5%-9%. Precision errors for BMC (BMD) were 0.90% (0.76%) without and 1.3 (0.86) with repositioning. Changes in the salinity of the water bath had a significant influence on the DXA results: At the 0.9% physiological level, BMC (-4.4%) and area (-4.1%), but not BMD, values were significantly lower (p < 0.005) compared with measurements in tap water. Fan beam DXA is a highly accurate and precise technique for measuring BMC and BMD in excised small animal bones. A physiological saline concentration in the water bath had a significant impact on BMC and area, but not on BMD, and should therefore be strictly controlled to avoid an underestimation of BMC.

Absorptiometry, Photon↗
PubMed2002

[Results of laryngeal nerve monitoring during thyroid operations--Studies and value for clinical practice].

Injuries of the laryngeal nerve still remain a source of morbidity for patients undergoing surgery for the thyroid gland. The incidence of permanent damage of the nerve varies from 0.5 % to 2.7 % depending on the series, but for special thyroid diseases like thyroid carcinoma or goiter recurrence the damage of the recurrent laryngeal nerve could be up to 25 %. For that reason several methods of monitoring the movement of the nerve while stimulation have been proposed. Such as inserting a needle into the vocal muscles or working with a surface laryngeal electrode that is attached above the cuff of the tube. For neither of those methods of nerve monitoring severe complications were described. The purchase costs for all the equipment are between 25.000 to 30.000 DM. All the published data regarding monitoring of the laryngeal nerve have been only observation studies with no control group and for that reason the results of the studies could not be obligatory statements. Furthermore not every nerve palsy has been identified by the monitoring of the laryngeal nerve, this method has a sensitivity of less than 70 %. Monitoring of the laryngeal nerve is a helpful clinical tool not only for training of surgeons but also during complicated thyroid surgery. Monitoring is especially useful for operations of thyroid carcinoma or revision procedures. But at the moment there is no randomised study available that shows any superiority of this new and expensive method over the standard therapy, therefore further studies are necessary. Until these studies exist the anatomical localisation of the nerve during surgical dissection is still the gold standard.

Humans↗
PubMed2002

[MR imaging of pancreatic lesions with Mn-DPDP. A histopathologic correlation].

PURPOSE: To examine the diagnostic accuracy of pancreatic lesions using mangafodipir-trisodium (Mn-DPDP) enhanced MR imaging. The imaging results were correlated with the histopathological results. MATERIAL AND METHODS: 40 patients with suspicion of pancreatic carcinoma were examined with MRI before and after i. v. administration of Mn-DPDP (Philips Gyroscan ACS NT 1.5 T, phased array body-coil: TSE T 2 with and without SPIR, TR 2000 ms, TE 120ms; FFE T 1 breathhold, TR 115 ms, TE 4.6 ms; MRCP, TR 6000 ms, TE 1200 ms; Teslascan i. v. 5 micromol Mn/kg; FFE T 1 breathhold SPIR, TR 140 ms, TE 4,6 ms). Two observers evaluated in consensus the number and characteristics of focal pancreatic lesions. The MR findings were correlated with histopathological findings retrospectively. RESULTS: The following lesions were found: adenocarcinoma (19), pancreatitis (8), adenocarcinoma within pancreatitis (3), insulinoma (2), hematoma (1), papillitis stenosans (1), signet ring cell carcinoma (1), metastasis of rectal carcinoma (1), papillary mesothelioma (1). In three patients there was no pathological finding. Mn-DPDP enhanced MRI showed a sensitivity of 100 % and a specificity of 56 %. CONCLUSION: Mn-DPDP enhanced MRI in conjunction with MRCP showed a high sensitivity for the detection of pancreatic lesions. However, the specificity is low, thus recommending Mn-DPDP enhanced MRI only as a complementary imaging method.

Ampulla of Vater↗
PubMed2001

The role of maternal axin in patterning the Xenopus embryo.

Regulation of the stability of beta catenin protein is a critical role of Wnt signaling cascades. In early Xenopus development, dorsal axis specification depends on regulation of beta catenin by both cytoplasmic and nuclear mechanisms. While the cytoplasmic protein axin is known as a key component of the cytoplasmic beta catenin degradation complex, loss-of-function studies are needed to establish whether it is required for dorso-ventral patterning in the embryo, and to test where in the embryo it carries out its function. Here, we show that embryos lacking maternal axin protein have increased levels of soluble beta catenin protein and increased nuclear localization of beta catenin in ventral nuclei at the blastula stage. These embryos gastrulate abnormally and develop with excessive notochord and head structures, and reduced tail and ventral components. They show increased expression of dorsal markers, including siamois, Xnr3, chordin, gsc, Xhex, and Otx2, decreased expression of Xwnt 8 and Xbra, and little alteration of BMP4 and Xvent1 and -2 mRNA levels. The ventral halves of axin-depleted embryos at the gastrula stage have dramatically increased levels of chordin expression, and severely decreased levels of Xwnt 8 mRNA expression, while BMP4 transcript levels are only slightly reduced. This dorso-anterior phenotype is rescued by axin mRNA injected into the vegetal pole of axin-depleted oocytes before fertilization. Interestingly, the phenotype was rescued by ventral but not dorsal injection of axin mRNA, at the 4-cell stage, although dorsal injection into wild-type embryos does cause ventralization. These results show directly that the localized ventral activity of maternal axin is critical for the correct patterning of the early Xenopus embryo.

Animals↗