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We studied kinetics of biotransformation synthetic implant for substituting defects of the bone tissue using methods of computer tomography, scintigraphy and morphology in vivo and in vitro. We found that the character of biotransformation is dependent on the degree of loaded or unloaded bone tissue.
Abnormalities in lung function are frequent findings in patients with terminal stage chronic liver disease. While spirometric parameters improve early after liver transplantation, a reduction in diffusion capacity has been reported up to 15 months after transplantation. It is unknown to what extent this disturbance in gas exchange occurs among long term survivors after liver transplantation. We assessed lung function in terms of spirometry, and gas exchange as well as pulmonary morphology by high resolution computed tomography (HRCT) in 40 patients 38 months (median, range 20-147 months) after liver transplantation. The prevalence of restrictive or obstructive changes was not different from predicted values. For the whole group of long-term survivors the carbon monoxide transfer coefficient (KCO) was reduced to 71.3 + 12.0% predicted (P < 0.05). HRCT revealed interstitial changes in only 2/40 (5.0%), emphysematous bullae in 2/40 (5.0%) and pleural thickening in 9/40 (22.5%). Diffusion abnormalities are prevalent in the majority of patients after liver transplantation, whereas spirometric abnormalities are absent also in the long term. The high prevalence of impaired gas exchange and the absence of interstitial lesions imply that changes in pulmonary blood vessels are the most likely cause.
In extrahepatic bile duct cancer, preoperative evaluation is important because only surgical excision of all detectable tumours is associated with improvement in 5-year survival. However, morphological imaging techniques, including computed tomography (CT), are still insufficient for accurate staging. The purpose of this study was to assess the additional value, in relation to CT, of 2-[(18)F]fluoro-2-deoxy- D-glucose positron emission tomography ((18)F-FDG PET) for the evaluation of extrahepatic bile duct cancer. Thirty patients with extrahepatic bile duct cancer underwent both (18)F-FDG PET and CT for initial staging. The results of the two modalities for evaluation of primary tumours and regional lymph nodes were compared with the final diagnoses based on pathological or clinical findings. The primary tumours were interpreted as malignant on the basis of CT in 24 (80%) of the patients, while (18)F-FDG PET revealed increased (18)F-FDG uptake in 18 (60%) of them. On the other hand, (18)F-FDG PET showed focal accumulation of (18)F-FDG in the bile duct in three of the six patients with equivocal findings on CT. The sensitivity, specificity and accuracy of CT for regional lymph node metastases were 54%, 59% and 57%, while those of (18)F-FDG PET were 38%, 100% and 73%, respectively. The specificity of (18)F-FDG PET for regional lymph node metastases was significantly higher than that of CT ( P<0.01). Of 14 patients with N1 or N2 disease diagnosed by CT, only seven (50%) had a final diagnosis of regional lymph node metastasis. In these 14 patients, (18)F-FDG PET accurately evaluated the N component of the disease in 12 patients (86%). In conclusion, in the initial staging of patients with extrahepatic bile duct cancer, (18)F-FDG PET offers additional value in relation to CT in evaluating both the primary tumour and regional lymph nodes.
During the past decade, the application of positron emission tomography with [(18)F]fluoro-2-deoxy-D-glucose (FDG-PET) has remarkably improved the management of cancer patients. Nevertheless, the clinical interpretation of FDG-PET scan can be difficult for two main reasons: (1) anatomical localisation of FDG uptake is not easy, (2) normal physiological accumulation of FDG can be misinterpreted as a pathologic area. It has been demonstrated that the visual correlation of PET with morphological procedures, such as computed tomography or magnetic resonance imaging, can improve the accuracy of PET alone. However, the time interval between the two scans, the time employed by the operator and difficulties in co-registering imaging of the abdomen and pelvis make the co-registration of separately obtained images clinically difficult. A novel combined PET/CT system has been built that improves the capacity to correctly localise and interpret FDG uptake. To date only a few studies have been conducted on the potential role of PET/CT in the management of breast cancer patients, but the better performance of this technique compared with PET alone should also be relevant for breast cancer application. In this review, we evaluate the possible impact on breast cancer diagnosis of PET/CT compared with PET alone, with respect to disease re-staging, treatment monitoring, preoperative staging and primary diagnosis. In addition, the possible role of PET/CT for radiotherapy planning is evaluated.
Computational modeling of dendritic morphology is a powerful tool for quantitatively describing complex geometrical relationships, uncovering principles of dendritic development, and synthesizing virtual neurons to systematically investigate cellular biophysics and network dynamics. A feature common to many morphological models is a dependence of the branching probability on local diameter. Previous models of this type have been able to recreate a wide variety of dendritic morphologies. However, these diameter-dependent models have so far failed to properly constrain branching when applied to hippocampal CA1 pyramidal cells, leading to explosive growth. Here we present a simple modification of this basic approach, in which all parameter sampling, not just bifurcation probability, depends on branch diameter. This added constraint prevents explosive growth in both apical and basal trees of simulated CA1 neurons, yielding arborizations with average numbers and patterns of bifurcations extremely close to those observed in real cells. However, simulated apical trees are much more varied in size than the corresponding real dendrites. We show that, in this model, the excessive variability of simulated trees is a direct consequence of the natural variability of diameter changes at and between bifurcations observed in apical, but not basal, dendrites. Conversely, some aspects of branch distribution were better matched by virtual apical trees than by virtual basal trees. Dendritic morphometrics related to spatial position, such as path distance from the soma or branch order, may be necessary to fully constrain CA1 apical tree size and basal branching pattern.
In mandibular joint-symptom-free subjects, post-stimulus EMG complexes (PSEC) were derived by standardized mechanical stimulation of an upper central incisor during clenching at a constant level of 5 per cent of maximal masseteric EMG activity. Seventy-two sweeps per subject were processed by means of a computer program, and different morphologies of the PSEC were seen. There appears to be no correlation with the Helkimo-index as a whole or its specific components. There is a strong correlation between tooth-grinding habits and the occurrence of a single inhibitory period. Patients with myofascial pain dysfunction consistently had a single inhibitory wave. When there was one affected side, the end latency of the second inhibitory wave was significantly shorter.
Neither immunologic nor genetic concepts of carcinogenesis have yet been decisively confirmed, and epigenetic theories, as formulated so far, are either non-predictive or insufficiently consistent with morphologic and experimental evidence. Computing data, concerned with carcinogenic mechanisms and neoplastic changes at the level of the endoplasmic reticulum, may lead to a new coherent understanding of tumor pathogenesis. Carcinogenic agents initiate biophysical perturbations, chemical alterations and conformational transitions in the membrane lattice of the endoplasmic reticulum. Foremost among the resulting neoplastic changes is an increased, irreversible separation of polyribosomes from membranes of the ergastoplasm. The carcinogenic process, apparently, deletes a protein required for polysome attachment. Since microsomal cytochromes can be synthesized by membrane-bound polysomes only, the translation of genetic information for their biosynthesis is irreversibly restricted. A similar, self-perpetuating deficiency may be postulated for the polysome attachment protein. Activities, depending on cytochromes P-450 and b5, are hampered, e.g. those of the monoxygenase system. Cholesterogenesis is derepressed. Ratios of phospholipids/cholesterol are decreased, and lipid-protein complexes, altered both in structure and function. Another distinct effect of the membrane-polysome separation is the unmasking of thiol-disulfide exchange enzymes which, in turn, stimulate the biosyntehsis of proteins and of deoxyribonucleotides involved in cell replication.
Percutaneous catheter drainage of both infected and non-infected pancreatic fluid collections is a safe, efficacious procedure. The results of this procedure depend upon proper selection of patients based upon their clinical status as well as the morphological findings depicted by computed tomography and endoscopic retrograde cholangiopancreatography, careful preprocedural planning and execution of the drainage procedure, good catheter care with follow-up imaging and contrast studies, and attention to the criteria of catheter removal. An average success rate of 80% should be expected with a complication rate of about 15%.
Non-invasive positron emission tomography (PET) was performed to identify changes in blood flow and metabolism, specific to early stages of tumour occurrence or recurrence. 2 patients with slowly progressive gliomas from early to late stages of tumour development were analysed by serial PET measurements of circulation and metabolism using 15O-gas and 18F-fluorodeoxyglucose. PET revealed a persistent depression of oxygen metabolism, as indicated by the regional oxygen extraction fraction or metabolic rate of oxygen, in the regions where tumours were later found. Abnormal blood flow and metabolism may precede the morphological changes detected by computed tomography (CT) in patients with gliomas.
Previous studies have shown sperm quality post-cryopreservation differs depending on the fraction of the seminal plasma boar spermatozoa are fortuitously contained in. As such, spermatozoa contained in the first 10 mL of the sperm-rich fraction (portion I) have better sustained handling procedures (extension, handling and freezing/thawing) than those contained in the ulterior part of a fractionated ejaculate (second portion of the sperm-rich fraction and the post-spermatic fraction, portion II). However, those studies were performed using pooled samples. In the present study, individual ejaculates were used. Split ejaculates (portions I and II) from five boars were frozen and thawed using a conventional freezing protocol, followed by computer-assisted motility and morphology analysis (CASA and ASMA, respectively), as well as an Annexin-V assay for spermatozoa from each boar and ejaculate portion. Significant differences between portions were observed in all ASMA-derived variables, except in one boar. Also significant differences were observed between boars and ejaculate portions in sperm quality post-thaw. We identified, however, boars showing best results of motility and sperm membrane integrity post-thaw in portion I, while in other boar the best results was observed in portion II. It is concluded that the identification of the ejaculate portion more suitable to sustain cryopreservation in each individual boar may be a readily applicable and easy technique to diminish variation in sperm freezability among boars.
OBJECTIVE: To explore the association between semen parameters and sperm DNA damage. DESIGN: Cross-sectional. SETTING: Andrology clinic. PATIENT(S): Two hundred fifty-seven men undergoing infertility assessment. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Sperm concentration and motility were measured using computer-assisted sperm analysis; morphology was scored using the strict criteria. The neutral comet assay was used to measure sperm DNA damage. Comet assay parameters included comet extent, percent DNA in the comet tail, and tail distributed moment, an integrated measure of length and intensity. We also scored cells that were too long to measure (>300 microm), which we referred to as cells with high DNA damage. RESULT(S): Men older than 35 years had a statistically significant increase in the number of cells with high DNA damage as compared with younger men. In age-adjusted regression analyses, the most consistent associations were found between semen parameters and the number of cells with high DNA damage. For an interquartile range change in the number of cells with high DNA damage, sperm concentration declined 14.2 x 10(6)/mL, motility declined 4.3%, and morphology declined 0.5%. Comet extent and percent DNA in the comet tail were also associated with a decline in sperm concentration and motility, respectively. CONCLUSION(S): Although there were associations between semen and comet assay parameters, their magnitudes were weak, suggesting that the comet assay provides additional independent information on sperm function.
BACKGROUND: Traditional repair of aortic arch aneurysms requires cardiopulmonary bypass, hypothermia, and circulatory arrest and is associated with considerable morbidity and mortality. Endovascular stent-graft placement has developed as a safe and effective treatment for various diseases of the descending aorta and, recently, even in delicate anatomic regions such as the aortic arch. The aim of this study is to review our clinical experience with endovascular treatment of aortic arch aneurysms after surgical transposition of supra-aortic vessels. METHODS: Fifteen patients received thoracic stent-graft implants after aortic debranching for repair of aortic arch aneurysms during the 3-year period ending December 31, 2005. All patients were not candidates for standard endovascular repair due to inadequate proximal landing zones on the aortic arch. Device design and implant strategy were determined by an evaluation of aortic morphology with angiography and computed tomography (CT) scanning. Stent-grafts were used to repair the arch after supra-aortic vessel transposition was performed. The endografts were implanted transfemorally or via an iliac Dacron conduit graft using standardized endovascular techniques. Follow-up was 100% complete (mean, 18 +/- 2.5 months; range, 12 to 36 months). Outcome variables included death and treatment failure (endoleak, aortic rupture, reintervention, or aortic-related or sudden death). Follow-up included clinical examination, chest radiograph, and CT at discharge, 6 months after stent-graft placement, and yearly thereafter. RESULTS: Stent-graft deployment success was 100% after staged supra-aortic vessel transposition. Patency of all endografts and conventional bypasses was 100%. No endoleak or graft migration was observed. There were no neurologic complications. One patient died 2 months after the procedure from pulmonary complications. CONCLUSION: Repair of aortic arch aneurysms by sequential transposition of the supra-aortic branches and endovascular stent-graft placement is feasible. Extended application of this technique will enable safe and effective treatment of a highly selected subgroup of patients with aortic aneurysms by avoiding conventional arch aneurysm repair in deep hypothermia and circulatory arrest.
INTRODUCTION: Infection is a frequent cause of morbidity and mortality in solid organ transplant recipients. It may occur at different periods after transplantation. We report four cases of mycotic aneurysms due to Candida albicans (CA) in renal transplant recipients occurring early after kidney transplantation. CASE REPORTS: Four patients (three men, one woman) aged from 24 to 55 years who underwent cadaveric renal transplantation from three different donors developed a mycotic aneurysm at 9 to 90 days after transplantation. In all cases aneurysms were located at the anastomosis between the renal graft artery and the iliac axis. The clinical presentations were fever in three cases, including endocarditis in one patient or deterioration of graft function in two cases and hemorrhagic shock secondary to a ruptured renal artery in the fourth case, which led to death. The arterial aneurysm was discovered at autopsy. The diagnosis of a mycotic aneurysm was based on morphological investigations: echotomography, spiral computed tomography, and arteriography. In all cases bacteriological studies (blood culture, culture of the aneurysmal wall and content) isolated CA. In three patients CA was isolated from the preservation solution; it was of the same phenotype as the one isolated from the aneurysm in one recipient. Antifungal therapy was started in patients who lived, but all kidney transplants had to be removed. Anatomical results of arterial reconstructions were satisfactory in all cases and remained so during the follow-up. CONCLUSION: The insidious presentation and clinical course of mycotic aneurysms due to CA require a high degree of suspicion to make the correct diagnosis.
BACKGROUND: The aim of this retrospective study was to evaluate the accuracy of fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG-PET) images, which were interpreted under daily routine conditions, in patients with Hodgkin's disease (HD) or non-Hodgkin lymphoma (NHL) for restaging after chemotherapy and/or radiotherapy. For this purpose, 18F-FDG-PET results were compared with morphological imaging methods and the patients' clinical background. METHODS: 121 PET images of 93 lymphoma patients (44 HD, 49 NHL) were investigated after chemotherapy/radiotherapy. For PET imaging, 160-200 MBq 18F-FDG was administered intravenously, followed by an infusion of 20 mg Furosemid in 250 mL saline. Whole-body 18F-FDG-PET images were obtained using a partial-ring PET scanner without attenuation correction. The morphological imaging consisted in computed tomography and ultrasound (CT/US) in all patients, additional MRI in some patients, and iliac crest biopsy in cases of suspicious bone marrow involvement. The standard of reference was composed of biopsy data, clinical status at the time of investigation, and follow-up of at least 12 months. The PET images were evaluated for their sensitivity, specificity and accuracy based on written reports, which were compiled from other imaging data and the clinical history of the patients. RESULTS: Sensitivity, specificity, and accuracy of 18F-FDG-PET was 91 %, 81 %, and 85 %; of CT/US, 88 %, 35 %, 56 %, respectively. Major sources of error in 18F-FDG-PET were due to asymmetric muscular hypermetabolism and inflammatory lesions misinterpreted as persistent viable lymphoma tissue. Furthermore, secondary malignancies other than lymphomas were another reason for misinterpretations of 18F-FDG-PET studies. CONCLUSIONS: 18F-FDG-PET showed a comparable sensitivity but a higher specificity and accuracy compared with CT/US. To achieve a high accuracy in 18F-FDG-PET, the nuclear medicine specialist needs imaging and clinical data as background information, which can only be acquired through close co-operation with the referring clinicians. Pharmacological muscular relaxation in the course of 18F-FDG-PET imaging may be advisable, as nonspecific muscular hypermetabolism was one of the problems at the image readings and a source of incorrect 18F-FDG-PET interpretations.
An 82-year-old woman developed acute neuropsychiatric signs (confusion, disorders of speech and vision) together with ataxic gait and left hemiparesis mainly affecting the lower limb. For 10 years she had been known to have chronic lymphatic leukaemia (CLL) which had not hitherto needed treatment. The patient had an exceptionally high leucocyte count (1,300,000/microliters), most of the cells being morphologically atypical lymphocytes. The computed tomogram of the skull showed a marginal zone infarct with a hypodense focus in the area of the right middle and posterior cerebral arteries, extending from the cortical to subcortical zones almost as far as the posterior horn. This was interpreted as a leukostasis syndrome with cerebral infarction due to rapid progression of the CLL. Significant reduction of leucocyte count with considerable improvement in clinical signs was achieved after three doses of vincristine and prednisone together with one cycle of COP (cyclophosphamide, vincristine, prednisone) therapy. Although the leucocyte count is not an important criterion in planning the therapy of CLL, in the event of rapidly increasing leucocytosis it is important to begin cytoreductive treatment in good time so as to avert the leukostasis syndrome.
OBJECTIVE: To evaluate of the impact of endovascular aneurysm repair on the rate of open surgical repair and on the overall treatment of abdominal aortic aneurysms (AAAs). METHODS: All patients with AAA who were treated during two consecutive 40-month periods were reviewed. During the first period, only open surgical repair was performed; during the subsequent 40 months, endovascular repair and open surgical repair were treatment options. RESULTS: A total of 727 patients with AAA were treated during the entire period. During the initial 40 months, 268 patients were treated with open surgical repair, including 216 infrarenal (81%), 43 complex (16%), and 9 ruptured (3%) aortic aneurysms. During the subsequent 40 months, 459 patients with AAA were treated (71% increase). There was no significant change in the number of patients undergoing open surgical repair and no significant difference in the rate of infrarenal (238 [77%]) and complex (51 [16%]) repairs. A total of 353 patients were referred for endovascular repair. Of these, 190 (54%) were considered candidates for endovascular repair based on computed tomography or arteriographic morphologic criteria. Analyzing a subgroup of 123 patients, the most common primary reasons for ineligibility for endovascular repair were related to morphology of the neck in 80 patients (65%) and of the iliac arteries in 35 patients (28%). A total of 149 patients underwent endovascular repair. Of these, the procedure was successful in 147 (99%), and 2 (1%) patients underwent surgical conversion. The hospital death rate was 0%, and the 30-day death rate was 1%. During a follow-up period of 1 to 39 months (mean 12 +/- 9), 21 secondary procedures to treat endoleak (20) or to maintain graft limb patency (1) were performed in 17 patients (11%). There were no aneurysm ruptures or aneurysm-related deaths. CONCLUSIONS: Endovascular repair appears to have augmented treatment options rather than replaced open surgical repair for patients with AAA. Patients who previously were not candidates for repair because of medical comorbidity may now be safely treated with endovascular repair.
One hundred and eighty-seven strains of listeriae, atypical lactobacilli, Brochothrix, Erysipelothrix and related Gram-positive bacteria were tested for 140 characters based on morphology, physiology and biochemistry. Computer analyses of the data resulted in the recovery of 20 phenons. Representative strains were examined for cytochrome content, cell wall, fatty acid and isoprenoid quinone composition and the G + C content of the DNA. The results indicate that the species Listeria monocytogenes, L. innocua and L. ivanovii are phenotypically very similar. L. grayi and L. murrayi are more distinct from these but are so similar to each other that L. murrayi should be regarded as a subspecies of L. grayi. Some of the atypical lactobacilli studied are members of the genus Brochothrix; the others probably represent four distinct species in a new genus.
We devise a two-dimensional model that mimics the recently observed power-law distributions for the amplitudes and durations of the acoustic emission signals observed during martensitic transformation [Vives et al., Phys. Rev. Lett. 72, 1694 (1994)]. We include a threshold mechanism, long-range interaction between the transformed domains, inertial effects, and dissipation arising due to the motion of the interface. The model exhibits thermal hysteresis and, more importantly, it shows that the energy is released in the form of avalanches with power-law distributions for their amplitudes and durations. Computer simulations also reveal morphological features similar to those observed in real systems.