Anaesthesia for total knee arthroplasty: efficacy of single-injection or continuous lumbar plexus associated with sciatic nerve blocks--a randomized controlled study.

Total knee arthroplasty (TKA) often results in marked postoperative pain. We compared in a randomized controlled study tramadol consumption, postoperative pain and patient satisfaction after primary TKA in patients who received a single injection lumbar plexus and sciatic nerve blocks or a continuous lumbar plexus and sciatic nerve blocks. Forty-four patients scheduled for unilateral total knee arthroplasty were allocated to the single shot group (group A) or to the catheter group (group B). All patients (in both groups) reported being satisfied with their anaesthetic management. Although pain scores and tramadol consumption appeared lower in the active infusion group, the differences did not reach statistical significance. This study confirms that either single injection or continuous infusion of Ropivacaine in lumbar plexus provides reliable and long-acting anaesthesia and analgesia.

Power Doppler ultrasonography with time-signal intensity curves in monitoring hepatocellular carcinoma and liver metastases after intralesional therapy.

PURPOSE: Analysis of time-intensity curves allows evaluation of the patterns of lesion enhancement before and after treatment. The aim of this study was to evaluate the diagnostic accuracy of time-intensity curves in monitoring intralesional therapy of focal hepatic lesions. MATERIALS AND METHODS: Twenty patients underwent intralesional therapy with either radiofrequency thermal ablation or percutaneous ethanol injection. Contrast-enhanced power Doppler ultrasound with analysis of time-intensity curves was performed one day before and one day after treatment. Targeted biopsy was then obtained to confirm the imaging findings. RESULTS: Before treatment, all lesions showed time-intensity curves characterised by high peaks of signal intensity and plateaus. Complete tumour necrosis, confirmed by targeted biopsy, was observed in patients showing no intralesional flow signals and time-intensity curves with low peak of signal intensity and absence of plateau after treatment. Biopsy confirmed the presence of residual neoplastic tissue in one patient exhibiting perilesional vascularity, absence of intralesional flow signals, and a time-intensity curve with high peak of signal intensity and plateau. CONCLUSIONS: According to our findings, time-intensity curves characterised by high peak of signal intensity and plateau might reflect the presence of perilesional or intralesional neoplastic tissue and provide important information on the effectiveness of the treatment.

Contrast-enhanced colour-Doppler sonography versus pH-metry in the diagnosis of gastro-oesophageal reflux in children.

PURPOSE: The aim of this study was to evaluate the accuracy of contrast-enhanced colour-Doppler ultrasound (CDUS) in the diagnosis of gastro-oesophageal reflux in children. MATERIALS AND METHODS: One hundred and twenty children (68 boys and 52 girls aged between 1 month and two years) with a clinical suspicion of gastro-oesophageal reflux (postprandial vomiting, weight loss, failure to thrive, anaemia, night-time coughing and crying, regurgitation, etc.) were studied by contrast-enhanced CDUS and subsequently by 24-hour pH-metry. Results of the two techniques were compared using the McNemar test. RESULTS: Gastro-oesophageal reflux was detected on CDUS in 84 patients and with 24-h pH-metry in 86. In all cases of reflux, CDUS visualised the passage of contrast material from the stomach into the abdominal and middle and distal third of the thoracic oesophagus, enabling assessment of the segment of oesophagus involved by the reflux. Compared with pH-metry, CDUS had a sensitivity of 98% (p<0.0001 with McNemar's test). CONCLUSIONS: In consideration of the results obtained and particularly of the low level of invasiveness, contrast-enhanced CDUS could be used to monitor children undergoing medical or surgical treatment for the complications of gastro-oesophageal reflux disease.

Functional study of the transplanted kidney with power Doppler US and time/intensity curves.

PURPOSE: Power Doppler ultrasound (US) with time-intensity curves was used to study renal graft function both in the absence of disease and with complications (acute tubular necrosis and chronic rejection) in an attempt to identify pathognomonic patterns. Time-intensity curves allow representation of the kidneys' wash-in and wash-out phases after intravenous administration of sonographic contrast material. MATERIALS AND METHODS: Fifty-six asymptomatic renal transplant patients (36 men and 20 women), 19 of whom had altered creatinine clearance levels, were studied by power Doppler US with time-intensity curves followed by biopsy. Ten asymptomatic patients with normal creatinine clearance levels were used as controls. RESULTS: Time-intensity curve analysis enabled identification of three groups of patients: group A, consisting of 27 patients showing peak enhancement between 50 and 65 s from intravenous administration of contrast material; group B, consisting of 16 patients with peak enhancement between 135 and 235 s; group C, consisting of three patients with peak enhancement between 100 and 130 s. CONCLUSIONS: Data showed significant variations according to renal graft function (no abnormality, acute tubular necrosis or chronic rejection). Although confirmation by a larger series is required, our findings appear to indicate pathognomonic patterns in patients with chronic rejection and acute tubular necrosis.

Imaging of Rathke's Cleft Cysts: Criteria for a Differential Diagnosis.

Rathke's cleft cysts are a congenital disorder of the pituitary gland and derive from abnormalities of the development of the adenohypophisis. The variability of the MRI signal of Rathke's cleft cyst hampers the differential diagnosis with the other cystic lesions of the pituitary gland. Nevertheless a comparison between the various findings reported from by author we reviewed indicates that a description of useful criteria for a differential diagnosis is possible. We suggest that the mean age at onset, the symptoms, the magnetic signal intensity, the location within the gland, the relations with the surrounding structures and the behaviour after contrast injection should always be considered in the diagnostic work-up of Rathke 's cleft cysts. There is no consensus in the literature on the correct therapeutic protocol. We suggest following up a small asymptomatic Rathke's cleft cyst (except mucoid cysts) because they do not generally enlarge. Surgery is instead the gold standard for symptomatic Rathke's cleft cysts, large Rathke's cleft cysts and mucoid Rathke's cleft cysts. Mucoid Rathke's cleft cysts, even when small, may cause an intense pituitary inflammation which could lead to irreversible endocrine dysfunction.

Synovial cyst of dens axis. A case report.

Synovial cyst of dens axis is a rare pathology accounting for 0.5%-1% of all cases of spinal synovial cysts. The lesion is normally found in the final part of the lumbar tract. The etiopathogenesis is uncertain and many theories abound Clinical inspection is important and the symptoms are caused by compression of posterior roots of spinal nerves and by spinal canal stenosis. Differential diagnosis is with disc herniation or tumours, but the diagnosis can only be established after CT and MRI examination. We describe the case of an 83-year-old man who underwent radiological exmaination after ten years of symptoms. The pathology was diagnosed only after the CT and MRI investigation.

Carotid body paraganglioma. Diagnosis and treatment by angiography.

Paraganglioma is a rare neoplasia of neural crest origin. It most commonly arises in carotid body, jugular bulb, tympanic plexus on the promontory, and along the vagal nerve pathway or anywhere along the paraganglia pathway. This review describes our experience of cervical paraganglioma. Although there is no consensus in the literature on preoperative angiographic embolization, we think angiography is the gold standard in the diagnosis and treatment of paraganglioma. A small paraganglioma probably does not usually require preoperative embolization because the risks may exceed the benefits. But angiography is mandatory in the diagnosis and treatment of large highly vascular paragangliomas. Imaging of the vascular map of the tumor, that is only possible by angiography, will help the neurosurgeon evaluate the real extension of the neoplasia and chose treatment modalities. Embolization is performed to decrease operative bleeding, shorten the surgery timing and avoid cranial nerve deficit. Cemal Umit Isik et al. studied four brothers with familial paragangliomas noting unexplained concomitant thyroid functional disorders in their patients. Because of the pedigree they thought this may have been a coincidence. Our reported case, unrelated to the Turkish family, also had hypothyroidism suggesting that the relation between paraganglioma and thyroid dysfunction may not be merely a coincidence.

Influence of chain end groups on the matrix-assisted laser desorption/ionization spectra of polymer blends.

The positive ion matrix-assisted laser desorption/ionization (MALDI) spectrum of an equimolar blend of Nylon 6 (Ny6) and hydroxyl-terminated polybutyleneterephthalate (PBT) shows a surprisingly strong imbalance between the two components. Since the average molar masses and the polydispersions of the two polymers are comparable, it follows that the efficiency of MALDI is quite different for the two components of the blend. This finding prompted us to a more detailed study, and to synthesize Ny6 and PBT samples terminated with different end groups, in order to analyze their blends by MALDI. The negative ion MALDI spectra of the mixtures investigated show that PBT samples do not yield signals, so that only Ny6 peaks appear in these spectra. By comparing positive and negative ion MALDI spectra of mixtures of Ny6 terminated with various end groups, it was found that the peak intensity depends on the nature of the end groups. The results reported in the present study may help to clarify some fundamental aspects of the mechanisms of ion formation, when MALDI mass spectrometry is applied to macromolecules. End group ionization efficiency appears to be the most important parameter in determining the relative intensity of peaks in the MALDI spectra of the polymer blends investigated. End-group-dependent ionization is the key to the rationalization of the relative peak intensities in MALDI spectra of polymer mixtures.

Matrix-assisted laser desorption/ionisation time-of-flight characterisation of biodegradable aliphatic copolyesters

Matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) and the off-line size exclusion chromatography matrix-assisted laser desorption/ionisation (SEC/MALDI) method has been applied to the structural characterisation and the molar mass (MM) determination of a series of biodegradable copolyesters synthesised by high temperature melt polycondensation reaction, and of two commercial copolyesters with the trade name Bionolle. The MALDI-TOF spectra of these copolymers showed the presence of cyclic oligomers in the lower mass region, in accord with expectations from polycondensation kinetics, and the presence of all linear species expected from their method of synthesis. The presence of unexpected linear species with olefin and carboxyl as end groups suggested the occurrence of undesirable thermal degradation processes during the melt polycondensation reaction. The absolute average molar masses obtained by the SEC-MALDI method turned out to be lower, by a factor of about two for succinate/adipate copolymers, and by a factor of three for succinate/sebacate copolymers, with respect to those computed by using polystyrene standards in SEC. Furthermore, the MALDI-TOF spectra of SEC fractions allowed not only the detection of linear and cyclic oligomers contained in these samples, but also the simultaneous determination of the average molar mass of both cyclic and linear oligomers. Due to the smaller hydrodynamic volume of cyclic chains with respect to linear ones, the ratio (M( cycle)/M( linear))( Ve) at a fixed elution volume was found to be 1.25, in good agreement with the theoretical value of 1.24. Copyright 2000 John Wiley & Sons, Ltd.

Analysis of poly(bisphenol A carbonate) by size exclusion chromatography/matrix-assisted laser desorption/ionization. 1. End group and molar mass determination

The determination of molar mass (MM) data for polydisperse polymers by SEC/MALDI involves the fractionation of samples through analytical size exclusion chromatography (SEC). Selected SEC fractions are then analyzed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and the mass spectra of these nearly monodisperse samples allow the determination of the average molar masses. The SEC/MALDI procedure has now been applied to two polycarbonate samples, PC1 and PC2. The results show that the MALDI spectra of the SEC fractions allow not only the detection of linear and cyclic oligomers contained in these samples, but also the simultaneous determination of their average molar masses. Two slightly differing SEC calibration plots were obtained, due to the smaller hydrodynamic volume of the polycarbonate cyclic chains with respect to the linear ones. In agreement with theory, the ratio (M(cycle)/M(linear))(Ve) at a fixed elution volume was found to be 1.22, independent of the molar mass values. Copyright 1999 John Wiley & Sons, Ltd.

Analysis of poly(bisphenol A carbonate) by size exclusion chromatography/matrix-assisted laser desorption/ionization. 2. self-association due to phenol end groups

We report here a case of apparent failure of the size exclusion chromatography/matrix-assisted laser desorption/ionization (SEC/MALDI) method to provide polymer fractions with narrow molar mass distribution, showing that intermolecular chain association is responsible for this phenomenon. Poly(bisphenol A carbonate) (PC) chains terminated with hydroxyl groups undergo self-association by hydrogen bonding, providing macromolecular aggregates with higher hydrodynamic volume. These aggregates are eluted through SEC columns at the same volume as higher molar mass chains, which remain non-associated. Thus, self-association affects negatively the SEC fractionation experiments, and even the sharpest SEC fractions contain a heterogeneous mixture of PC chains of different size. When the off-line SEC/MALDI procedure is applied, the SEC fraction is diluted in the matrix which, being a dissociating medium (carboxylic acid) for hydrogen-bonded aggregates, suppresses the chains' self-association. Therefore, the MALDI spectra of these PC fractions indicate a polydisperse character, with irregular bimodal distributions of peaks. As a consequence, in the presence of chain association, the SEC/MALDI method for the calculation of molar masses of polymers cannot be directly applied. In the present case we have found that, under opportune experimental conditions, self-association in polycarbonates can be avoided, so that nearly monodisperse SEC fractions can be obtained and the SEC/MALDI method can be applied. Our results also show that MALDI is a very sensitive technique for the detection of association of polymers in dilute solutions. Copyright 1999 John Wiley & Sons, Ltd.

Spinal-flexibility-plus-aerobic versus aerobic-only training: effect of a randomized clinical trial on function in at-risk older adults.

BACKGROUND: As exercise is associated with favorable health outcomes, impaired older adults may benefit from specialized exercise interventions to achieve gains in function. The purpose of this study was to determine the added benefit of a spinal flexibility-plus-aerobic exercise intervention versus aerobic-only exercise on function among community-dwelling elders. METHODS: We employed a randomized clinical trial consisting of 3 months of supervised exercise followed by 6 months of home-based exercise with telephone follow-up. A total of 210 impaired males and females over age 64 enrolled in this study. Of these, 134 were randomly assigned to either spinal flexibility-plus-aerobic exercise or aerobic-only exercise, with 116 individuals completing the study. Primary outcomes obtained at baseline, after 3 months of supervised exercise, and after 6 months of home-based exercise included: axial rotation, maximal oxygen uptake (VO2max); functional reach, timed-bed-mobility; and the Physical Function Scale (PhysFunction) of the Medical Outcomes Study SF-36. RESULTS: Differences between the two interventions were minimal. Overall change scores for both groups combined indicated significant improvement for: axial rotation (p=.001), VO2max (p=.0001), and PhysFunction (p=.0016). Secondary improvements were noted for overall health (p=.0025) and reduced symptoms (p=.0008). Differences between groups were significant only for VO2max (p=.0014) at 3 months with the aerobic-only group improving twice as much in aerobic capacity as the spinal flexibility-plus-aerobic group. Repeated measures indicated both groups improved during the supervised portion of the intervention but tended to return toward baseline following the home-based portion of the trial. CONCLUSIONS: Gains in physical functioning and perceived overall health are obtained with moderate aerobic exercise. No differential improvements were noted for the spinal flexibility-plus-aerobic intervention.

Determination of tazobactam and piperacillin in human plasma, serum, bile and urine by gradient elution reversed-phase high-performance liquid chromatography.

A gradient elution high-performance liquid chromatographic method is described for the analysis of the beta-lactamase inhibitor tazobactam (YTR-830H) and a semi-synthetic parenteral penicillin, piperacillin, in human plasma, serum, bile and urine. The assay for plasma, serum and bile involves deproteinization with acetonitrile and the removal of lipids with dichloromethane; urine is diluted with buffer. Separation and quantitation are achieved using a mobile phase based on ion-suppression chromatography on a C18 reversed-phase column with ultraviolet detection at 220 nm. The limit of quantitation for both compounds is 1.0 microgram/ml in plasma, serum and bile using a 0.2-ml sample and 50.0 micrograms/ml in urine using a 0.1-ml sample. The method has been validated by preparing and analyzing a series of fortified samples (range 1.0-200 micrograms/ml for each compound in plasma, serum and bile and 50.0-10,000 micrograms/ml for each compound in urine). Excellent linearity, accuracy, precision and recovery were obtained. The method was not interfered with by other endogenous components, nor by other commonly administered antibiotics such as amoxicillin, mezlocillin, cefometazole and cefotaxime. The assay has been successfully applied to the analysis of samples from pharmacokinetic studies in man and animals.

Epstein-Barr virus-transformed human B lymphocytes endocytose autologous and heterologous red blood cells.

Epstein-Barr virus (EBV)-transformed B lymphocytes, either isolated from a patient with EBV-induced infectious mononucleosis or obtained by in vitro infection of B lymphocytes of donors in different clinical conditions, have been tested for the ability to endocytose particulate forms of antigens, such as human, sheep or mouse red blood cells. By light and electron microscopy, it has been found that EBV-transformed B cells are able to bind and internalize human autologous and allogeneic erythrocytes, as well as sheep and mouse erythrocytes, independent of the specificity of the secreted immunoglobulins. The ability of EBV-transformed B lymphocytes to endocytose and process particulate forms of autoantigens during infectious mononucleosis might have a role both in the production of heterophile antibodies and in EBV-induced autoimmunity.

Interleukin-1-like activity produced by hybrids constructed with Epstein-Barr-virus-transformed human B lymphocytes and mouse myeloma cells.

Peripheral blood B lymphocytes from a donor with positive tuberculin skin test reaction were transformed into lymphoblastoid cell lines by Epstein-Barr virus and then fused by polyethylene glycol with mouse myeloma cells. Human-mouse hybrid cells producing human IgM monoclonal antibody to purified protein derivative of tuberculin were isolated, and the concentrated supernatant of one of these cell hybrids was tested for the capacity of interfering with DNA synthesis of human and mouse lymphocytes. The hybrid cell supernatant was found to contain soluble factors that increased DNA synthesis in unstimulated human and mouse lymphocytes and that, conversely, decreased DNA synthesis in concanavalin-A-stimulated cells. Gel filtration experiments showed that these antagonistic activities were due to at least two different factors, one of which resembled human interleukin-1 in biochemical and biological properties.

Determination of (E)-1,2,3,4-tetrahydro-1,1,4,4-tetramethyl-6-(1-methyl-2- phenylethenyl) naphthalene, an antiacne agent, and its phenolic metabolite in plasma by reversed-phase high-performance liquid chromatography.

A rapid, sensitive and selective high-performance liquid chromatographic (HPLC) assay was developed for the determination of (E)-1,2,3,4-tetrahydro-1,1,4,4-tetramethyl-6-(1-methyl-2- phenylethenyl)naphthalene (I) and its phenolic metabolite, (E)-4-[2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-2- methylethenyl]phenol (II) in plasma. The assay for both compounds involves precipitation of the plasma proteins with acetonitrile, followed by extraction of the entire mixture into methyl tert.-butyl ether and subsequent analysis by reversed-phase HPLC. The overall recovery of I and II was 96.9 +/- 5.3 and 96.2 +/- 5.8% for dog plasma, 80.0 +/- 4.0 and 93.5 +/- 5.0% for human plasma and 97.4 +/- 2.9 and 97.6 +/- 9.6% for rat plasma, respectively. The sensitivity limit is 20 ng/ml of plasma for both compounds I and II using UV detection at 280 nm. The HPLC assay was used in studies in the dog and in the rat.

Multiple organ-reactivity of monoclonal autoantibodies to mouse erythrocytes.

Autoantibodies reacting with bromelain-treated autologous mouse red blood cells (Br-MRBC) are spontaneously produced by normal mice. In order to understand the biological significance of these autoantibodies, anti-Br-MRBC monoclonal autoantibodies have been prepared and studied for reactivity with a panel of frozen tissue sections from organs of normal mice by direct immunofluorescence. It has been found that the anti-Br-MRBC monoclonal autoantibodies are polyspecific, since they react with cells in multiple organs.

Determination of the agonist-antagonist anxiolytic agent 6-(2-chlorophenyl)-4-hydroxy-4H-imidazo[1,5-a]-[1,4]benzodiazepine- 3-carboxamide and its benzophenone carboxylic acid metabolite in plasma by high-performance liquid chromatography.

A rapid, sensitive and selective high-performance liquid chromatographic (HPLC) assay was developed for the determination of 6-(2-chlorophenyl)-4-hydroxy-4H-imidazo[1,5-a]-[1,4]benzodiazepine- 3-carboxamide (I) and its benzophenone carboxylic acid metabolite, 1-[2-(2-chlorobenzoyl)phenyl]-4-(aminocarbonyl)-1H-imidazole-5-car boxylic acid (II) in plasma. The assay involves the extraction of both compounds into benzene from buffered plasma (pH 5.4) and subsequent analysis by reversed-phase HPLC. The overall recovery of I and II is 98.3 +/- 9.4 and 59.7 +/- 15.7% for dog plasma, 86.0 +/- 14.7 and 52.8 +/- 15.1% for rat plasma and 98.1 +/- 9.3 and 66.9 +/- 18.0% for human plasma, respectively. The sensitivity limit of the assay for I and II is 20.0 and 40.0 ng/ml of plasma using ultraviolet detection at 254 nm. The assay was used in studies in dog and rat.

Epstein-Barr virus-transformed B cells process and present Mycobacterium tuberculosis particulate antigens to T-cell clones.

We have analyzed the presentation of mycobacterial antigens by Epstein-Barr virus-transformed human B (EBV-B) cells to mycobacteria-specific T-cell clones and lines, and to purified resting T cells. EBV-B cells were able to process and present not only soluble forms of antigen, such as PPD and the expressate preparation of M. tuberculosis strain H37Rv, but also particulate forms of antigen, such as whole mycobacterial H37Rv or M. bovis organisms. Electron microscopy studies demonstrated the capacity of EBV-B cells to phagocytose mycobacterial cells in 18 hr and pulsing experiments confirmed that an 18-hr of incubation is required for an efficient processing and presentation of mycobacterial determinants to T cells. The processing of whole-H37Rv particulate antigen by EBV-B cells was inhibited by the lysosomotrophic compound chloroquine and by high doses of irradiation. Finally, the analysis of the presentation of soluble and particulate mycobacterial antigens by PPD-positive and PPD-negative EBV-B cell clones has shown a preferential presentation of both forms of antigen by PPD-positive EBV-B clones.

Human monoclonal antibody to purified protein derivative of tuberculin produced by hybrids constructed with Epstein-Barr virus-transformed B lymphocytes and mouse myeloma cells.

A method of producing human monoclonal antibody by combining somatic cell hybridization technology with the capability of Epstein-Barr virus (EBV) to transform human B lymphocytes is described. Peripheral blood lymphocytes from a donor with positive tuberculin skin test reaction were transformed by EBV and then tested for antibody production to mycobacterial purified protein derivative (PPD) by an enzyme-linked immunosorbent assay. Two EBV-transformed lymphoblastoid cell lines making IgM antibodies to PPD were obtained. One of these cell lines was fused by polyethylene glycol with a murine hypoxanthine-guanine phosphoribosyl transferase-deficient myeloma cell line that had been selected for resistance to ouabain. The human-mouse hybrids were selected in ouabain-containing HAT medium and 11 heterohybridomas producing IgM antibody to PPD were obtained. One of these was cloned by limiting dilution with efficiency at least 20-fold higher than parent EBV-transformed cell line. Heterohybridoma subclones reached levels of IgM antibody as high as 75.0 micrograms/ml of culture medium, whereas IgM production of EBV-transformed B cell clones ranged between 3.0 and 4.0 micrograms/ml.