Contribution of cholescintigraphy to the early diagnosis of acute acalculous cholecystitis in intensive-care-unit patients

Thirty-two intensive care unit patients (78% on long-term total parenteral nutrition) suspected of having acute acalculous cholecystitis (AAC) were studied prospectively. All of these patients underwent abdominal ultrasonography and cholescintigraphy with technetium-99m mebrofenin. Morphine sulphate (0.04 mg/kg) was administered only if the gallbladder was not visualised after 1 h (16 patients). The final diagnosis was reached after clinical improvement, or upon the discovery of another aetiology for the symptoms presented, or on the basis of histopathology following cholecystectomy (when this was performed). We analysed the contribution of individual cholescintigraphic findings (I: non-visualisation of the gallbladder during the first 60 min of the examination; II: persistent non-visualisation of the gallbladder 30 min following morphine administration; III: non-visualisation of the small bowel for at least 90 min) and their various combinations. We obtained a sensitivity of 79% and a specificity rate 100% using the interpretative criteria "I and II or III". Excluding obstructive syndrome ("I and II"), the sensitivity and specificity figures were 70% and 100% respectively (28 patients). We had no false-positive results in our patient population. Cholescintigraphy was found to complement ultrasonography, which had either good sensitivity (93%) and poor specificity (17%), when at least two of the three major signs were present (sludge, thickened wall, gallbladder distension), or poor sensitivity (36%) and good specificity (89%) when all three signs were present. We conclude that cholescintigraphy is a useful tool for early diagnosis of AAC in critically ill patients, in whom ultrasonography alone does not provide enough information to permit a sufficiently early decision regarding the use of surgery.

Glutamine synthetase in the phloem plays a major role in controlling proline production

To inhibit expression specifically in the phloem, a 274-bp fragment of a cDNA (Gln1-5) encoding cytosolic glutamine synthetase (GS1) from tobacco was placed in the antisense orientation downstream of the cytosolic Cu/Zn superoxide dismutase promoter of Nicotiana plumbaginifolia. After Agrobacterium-mediated transformation, two transgenic N. tabacum lines exhibiting reduced levels of GS1 mRNA and GS activity in midribs, stems, and roots were obtained. Immunogold labeling experiments allowed us to verify that the GS protein content was markedly decreased in the phloem companion cells of transformed plants. Moreover, a general decrease in proline content in the transgenic plants in comparison with wild-type tobacco was observed when plants were forced to assimilate large amounts of ammonium. In contrast, no major changes in the concentration of amino acids used for nitrogen transport were apparent. A (15)NH(4)(+)-labeling kinetic over a 48-hr period confirmed that in leaves of transgenic plants, the decrease in proline production was directly related to glutamine availability. After 2 weeks of salt treatment, the transgenic plants had a pronounced stress phenotype, consisting of wilting and bleaching in the older leaves. We conclude that GS in the phloem plays a major role in regulating proline production consistent with the function of proline as a nitrogen source and as a key metabolite synthesized in response to water stress.

Subcellular localization of mannose 6-phosphate glycoproteins in rat brain

The intracellular transport of soluble lysosomal enzymes relies on the post-translational modification of N-linked oligosaccharides to generate mannose 6-phosphate (Man 6-P) residues. In most cell types the Man 6-P signal is rapidly removed after targeting of the precursor proteins from the Golgi to lysosomes via interactions with Man 6-phosphate receptors. However, in brain, the steady state proportion of lysosomal enzymes containing Man 6-P is considerably higher than in other tissues. As a first step toward understanding the mechanism and biological significance of this observation, we analyzed the subcellular localization of the rat brain Man 6-P glycoproteins by combining biochemical and morphological approaches. The brain Man 6-P glycoproteins are predominantly localized in neuronal lysosomes with no evidence for a steady state localization in nonlysosomal or prelysosomal compartments. This contrasts with the clear endosome-like localization of the low steady state proportion of mannose-6-phosphorylated lysosomal enzymes in liver. It therefore seems likely that the observed high percentage of phosphorylated species in brain is a consequence of the accumulation of lysosomal enzymes in a neuronal lysosome that does not fully dephosphorylate the Man 6-P moieties.

[Neurological examination and brain computed tomography in the initial staging of non-small-cell lung cancer: a prospective study]

Brain metastases occur in 17 to 40% of lung carcinoma and 30 to 60% of brain metastases originate from a lung carcinoma. Brain metastasis directly influences prognosis and treatment of lung cancer. The aim of this study was to prospectively compare the findings of the neurological examination performed by a neurologist and results of double dose delayed computed tomography (CT DDD). The neurologist and radiologist were blinded to each other's results. Patients included had non-small-cell lung cancer (NSCLC) and were neurologically asymptomatic with no other cancer. From November 1993 to May 1996, 135 patients were included (126 men and 9 women). Ninety neurological examinations were normal, 34 suggested brain metastasis and 11 were abnormal but did not suggest brain metastasis. One hundred thirteen CTs were normal, 1 showed a brain metastasis and 11 were abnormal but did not evidence brain metastasis. The sensitivity, specificity, positive predictive value and negative predictive value of the neurological examination were 73, 79, 23 and 97% respectively. The presence of brain metastasis was directly related to tumor stage but not to age or histology. We suggest that brain CT DDD should be performed in stage IIIA, IIIB, IV whereas in stage I or II, the neurological examination is sufficient. However, a larger number of patients would be required to confirm these findings.

[Importance of cerebral tomoscintigraphy using technetium-labeled sestamibi in the differential diagnosis of current tumor vs. radiation necrosis in subtentorial glial tumors in the adult]

CT scan and MR imaging are not always reliable in the differential diagnosis between radionecrosis and recurrence of brain tumor. We describe the results of a prospective study using 99mTc Sestamibi. 22 patients were included. The histology of the tumor was astrocytoma (grade 2-4) oligodendroglioma (grade 2-3) or mixed (grade 2-3). SPECT was performed using a Tomomatic 564, 1 h after the injection i.v. of 370 MBq of 99mTc Sestamibi. Ten slices parallel to the orbitomeatal plane were obtained. Two index were calculated i) CI: ratio of the mean counts in the lesion to the mean counts in the contralateral choroid plexus and ii) MI: ratio of the mean counts in the lesion to the contralateral mirror area. The results were compared to stereotactic biopsies or to clinical course at 6 months. Twelve patients out of 22 showed an increased uptake of the tracer and 11/12 presented with a recurrence. In 10 patients without fixation, 4 were false negative. The sensitivity for the detection of tumor recurrence was 73% and specificity was 85%. The positive predictive value was 91% and the negative predictive value was 60%. The use of a cut-off value superior to 2 for MI and superior to 0.5 for CI appears to be a good criterion for helping the diagnosis of relapse according to the analysis of Receiver Operating Characteristic curves (ROC). A positive SPECT was conclusive for the diagnosis of recurrence but a negative SPECT did not allow to assess the absence of recurrence. Limits of methods have to be stressed and searched for a better understanding of false negatives.

Oxidized LDL activates STAT1 and STAT3 transcription factors: possible involvement of reactive oxygen species

The effect of cupric ion-oxidized low density lipoprotein (Cu-LDL) or endothelial cell-oxidized LDL (E-LDL) on STAT1 and STAT3 (signal transducers and activators of transcription) DNA binding activity was investigated by electrophoretic mobility shift assay in human endothelial cells. Both oxidized LDL enhanced STAT1 and STAT3 binding to their respective consensus binding sites. Furthermore, the activation of STATs was proportional to the oxidation degree of LDL in that the highly oxidized Cu-LDL exhibited a more marked effect than E-LDL. Oxidized LDL induced an intracellular oxidative stress, as shown by the increase in the intracellular level of lipid peroxidation products (thiobarbituric acid-reactive substances) and in the level of reactive oxygen species, measured by the fluorescence of dichlorofluorescein diacetate. The binding activity of STAT1 and STAT3 paralleled these two parameters, which suggests that it is dependent upon the redox state of the cell. The activation of STATs by oxidized LDL was almost completely inhibited by the lipophilic antioxidant vitamin E, and partially antagonized by the hydrophilic thiol-containing compound N-acetylcysteine, suggesting that the oxidative stress induced by oxidized LDL is involved in the observed phenomenon. Furthermore, the lipid extract of Cu-LDL also activated STAT1 and STAT3. Since the STAT pathway plays a key role in cytokine and growth factor signal transduction, the activation of STATs by oxidized LDL might be related to their proinflammatory and fibroproliferative effect in the atherosclerotic plaque.

Identification of cytosolic Mg2+-dependent soluble inorganic pyrophosphatases in potato and phylogenetic analysis

Using polyclonal antibodies raised against a previously cloned potato Mg2+-dependent soluble inorganic pyrophosphatase (ppa1 gene) [8], a second gene, called ppa2, could be isolated. A single locus homologous to ppa2 was mapped on potato chromosomes, unlinked to the two loci identified for ppa1. From a phylogenetic and structural point of view, the PPA1 and PPA2 polypeptides are more closely related to prokaryotic than to eukaryotic Mg2+-dependent soluble inorganic pyrophosphatases (soluble PPases). Subcellular localization by immunogold electron microscopy, using sections from leaf parenchyma cells, showed that PPA and PPA2 are localized to the cytosol. Based on these observations, the likely phylogenetic origin and the physiological significance of the cytosolic soluble pyrophosphatases are discussed.

Prevalence of bovine virus diarrhoea virus infection in Belgian white blue cattle in southern Belgium

A study was conducted in Southern Belgium to determine the prevalence of bovine viral diarrhoea virus (BVDV) infection in Belgian White Blue herds. Blood samples were taken from 9685 cattle, representing all the stock on 61 farms, by local veterinarians to screen for persistently infected animals and to determine their serological status against BVDV. Some of the herds (42.5%) were selected because of a prior positive diagnosis of BVDV or on the grounds of suspicion of BVD. A capture enzyme-linked immunosorbent assay (ELISA) was used to test for antigen. The prevalence of persistently infected animals was 0.75% overall and 1.46% in the 27 herds with at least one persistently infected animal. The prevalence of seropositive animals was determined with a competitive antibody ELISA and was found to be 65.5% for the animals as a whole but 53.8% for the herds without positively infected animals and 76.6% for the herds with at least one such animal. All the herds contained seropositive animals.

Ultrastructural and physicochemical characterization of the hepatitis C virus recovered from the serum of an agammaglobulinemic patient

Hepatitis C virus (HCV) morphology and physicochemical properties remain unclear because HCV usually circulates in a complexed form in association with immunoglobulins. In the present work, we were interested in the characterization of HCV particles derived from the serum of an anti-HCV negative/HCV RNA positive agammaglobulinemic patient suffering from chronic type C hepatitis. Physicochemical properties of the virus particles were determined by serum centrifugation on a 10-60% isopycnic sucrose density gradient. HCV RNA quantified by bDNA was found in a major peak at density 1.13 g/ml and in a minor peak at densities 1.05-1.07 g/ml. By electron microscopy, 45 nm large core-like particles were found at the 1.13 g/ml density while 60 nm large virus-like particles similar to other members of the Flaviviridae family were visualized at the 1.06-1.07 g/ml densities. This confirms some studies reporting the low density of HCV as compared to other members of the Flaviviridae family.

Technetium-99m sestamibi brain single-photon emission tomography for detection of recurrent gliomas after radiation therapy

Technetium-99m sestamibi (MIBI), an alternative radiopharmaceutical for myocardial perfusion imaging, has also been proposed for use as an imaging agent for various tumours, including breast cancer, lung cancer, lymphomas, melanomas and brain tumours. After routine radiation therapy, deteriorating clinical status or treatment failure may be due to either radiation-induced changes or recurrent tumour. Computed tomography and magnetic resonance imaging offer imperfect discrimination of tumour viability and radionecrosis. Against this background we undertook a retrospective study of 35 malignant glioma patients in whom clinical deterioration had occurred, in order to clarify the value of 99mTc-MIBI SPET in identifying tumour recurrence. SPET was performed 15 min after intravenous injection of 1110 MBq with a dual-headed gamma camera using a fan-beam collimator. Transverse, coronal and sagittal views were reconstructed. Intense MIBI uptake was found in 31 patients. This uptake was correlated with tumour recurrence as proved by histology and/or rapid, fatal evolution of these cases. The statistical analysis performed on this population of patients with MIBI uptake revealed a group of patients with a long mean survival and a group with a short mean survival. Two subgroups were found within each of these groups, according to the functional index ratio (tumour uptake/pituitary gland uptake ratio). No MIBI uptake was found in four patients who are still alive and can be considered to be disease-free. In those cases showing MIBI uptake, death occurred an average of 6.69 months following brain SPET. According to our results, the specificity and sensitivity of 99mTc-MIBI brain SPET seem to be high. Moreover, this technique is more accurate than computed tomography or magnetic resonance imaging for discriminating between tumour recurrence and radionecrosis.

Polyunsaturated fatty acid enrichment enhances endothelial cell-induced low-density-lipoprotein peroxidation

Oxidative modification of low-density lipoprotein (LDL) is an important feature in the initiation and progression of atherosclerosis. LDL modification by endothelial cells was studied after supplementation of the cells with oleic acid and polyunsaturated fatty acids (PUFA) of the n-6 and n-3 series. In terms of the lipid peroxidation product [thiobarbituric acid reactive substances (TBARS)] content and diene level of the LDL particle, oleic acid had no significant effect, and linoleic acid was poorly effective. Gamma linolenic acid (C18:3,n-6) and arachidonic acid (C20:4,n-6) increased by about 1.6-1.9-fold the cell-mediated LDL modification. PUFA from the n-3 series, alpha linolenic acid (C18:3,n-3), eicosapentaenoic acid (C20:5,n-3) and docosahexaenoic acid (C22:6,n-3), induced a less marked effect (1. 3-1.6-fold increase). The relative electrophoretic mobility of the LDL particle and its degradation by macrophages were enhanced in parallel. Concomitantly, PUFA stimulated superoxide anion secretion by endothelial cells. The intracellular TBARS content was also increased by PUFA. Comparison of PUFA from the two series indicates a good correlation between LDL oxidative modification, superoxide anion secretion and intracellular lipid peroxidation. The lipophilic antioxidant vitamin E decreased the basal as well as the PUFA-stimulated LDL peroxidation. These results indicate that PUFAs with a high degree of unsaturation of the n-6 and n-3 series could accelerate cell-mediated LDL peroxidation and thus aggravate the atherosclerotic process.

Hepatitis C in a hemodialysis unit: molecular evidence for nosocomial transmission

This study reports four cases of transmission of the rare hepatitis C virus genotype 4 which occurred in a hemodialysis unit and originated from a single source of infection. Phylogenetic analyses performed with the NS5b domain showed that all four patients with secondary infections were infected with virus strains very similar to that of the index patient. Cross infections probably resulted from breaches in safety precautions and lack of dialysis machine sterilization.

Mechanisms of severe, immediate reactions to iodinated contrast material

PURPOSE

To measure and elucidate the mechanisms of presumed mediators of unexpected severe, immediate reactions to iodinated contrast materials.

MATERIALS AND METHODS

In a multicenter study, 20 patients with mild to severe reactions to iodinated contrast material and 20 control subjects without reactions were evaluated. Ionic contrast material was associated with 18 (90%) of 20 reactions. Concentrations of plasma histamine, tryptase, urinary methylhistamine, specific immunoglobulin E (IgE) against ioxitalamate or ioxaglate, and the anaphylatoxins C3a and C4a were measured with radioimmunoassays; complement C3 and C4 levels were measured with nephelometry.

RESULTS

Histamine levels were increased in 14 patients; tryptase levels, in 16; and methylhistamine levels, in six. Histamine and tryptase values correlated with the severity of the reaction (P < .02 and P < .004, respectively). Significantly higher levels of specific IgE against ioxaglate (P < .005) and ioxitalamate (P = .045) were found in patients. No differences were found for complement fractions. Skin test results in two patients with life-threatening reactions were positive for the administered contrast material.

CONCLUSION

Histamine release and mast cell triggering are related to severe reactions. An IgE-related mechanism is strongly suspected. Radiologists should be trained to identify and treat anaphylactic shock in patients who react to iodinated contrast material.

The kinetics of antibodies against hepatitis C virus may predict viral clearance in exposed hemophiliacs

Several studies have reported the spontaneous loss of hepatitis C virus (HCV) antibodies in HCV-exposed persons. However, the relationship between seroreversion and spontaneous virus clearance has yet to be precisely determined in a single homogeneous population of untreated immunocompetent patients. In this study, 32 human immunodeficiency virus-seronegative hemophiliacs who had been exposed to HCV were followed for a mean duration of 141 months; 22 remained chronic carriers (68.8%). All but 1 of the nonviremic patients (90.0%) showed partial (8 cases) or complete (2 cases) seroreversion. In contrast, all but 1 of the viremic patients (95.1%) had a stable serologic profile when analyzed by a recombinant immunoblot assay. The results indicate that any HCV antibody-positive immunocompetent patient with no detectable serum HCV RNA and normal alanine aminotransferase values and whose serial samples show a progressive decrease in the level of HCV antibodies present may be considered as having a resolved infection.

The importance of 99Tcm-DMSA renal scintigraphy in the follow-up of acute pyelonephritis in children: comparison with urographic data

At present, 99Tcm-dimercaptosuccinic acid (DMSA) renal scintigraphy is the most sensitive examination for the detection of parenchymal damage during acute pyelonephritis (APN) in children. This prospective study had three aims: (1) to evaluate the medium-term evolution of the scintigraphic abnormalities, to find a prognostic criterion of scintigraphic evolution; (2) to assess the correlation between the severity of early or late scintigraphic damage and selected clinical factors; and (3) to compare the permanent scintigraphic renal scars with intravenous urography (IVU) 2 years after the acute infection. Seventy-four children (mean age 32 months), presenting with a first clinical episode of pyelonephritis and an initial scintigraphic abnormality, were included in the study. Patients with a history of urinary tract infection (UTI), uropathy other than vesico-ureteral reflux (VUR) and a relapse of acute pyelonephritis were excluded. All children underwent control scintigraphy (mean 9 months after APN) and 43 had an IVU (mean 26 months after APN). Fifty-seven children (77%) still have scintigraphic abnormalities of varying severity (7 atrophic kidneys). Initial relative DMSA uptake of less than 45% results in a worse scintigraphic prognosis. The age of the child has no bearing on the severity of the initial renal involvement or on the evolution of the scintigraphic abnormalities. The rapid introduction of antibiotics (< 12 h) significantly improves the scintigraphic prognosis (P < 0.01). The presence of reflux (n = 39) leads to more serious initial damage, but we did not find any effect on later evolution in this study, in which all reflux was low grade in nature. Among the 43 children who had an IVU, 5 showed typical urographic and scintigraphic renal scars in the corresponding region and 38 showed a normal IVU with 28 cases of scintigraphic abnormalities. A DMSA scan is more sensitive than IVU for the detection of renal scarring after a first episode of APN.

[Anti-HCV serology for screening, diagnosis and surveillance of hepatitis C: role of the immunoblot]

Screening for antibody to hepatitis C virus (anti-HCV) is usually carried out using microplate enzyme immunoassays (EIA). According to French Ministry of Health recommendations, any positive or dubious result has to be controlled on a second blood sample with a anti-HCV assay differing from the one used for the initial screening. This second test can either be another EIA or an immunoblot assay. The present article investigates the advantage of a strip immunoblot assay including 4-viral peptides (Riba-3) for this control. The use of Riba for the early diagnosis of hepatitis C infection and for the follow-up of infected patients is also evaluated. Riba can be used to assess false positive EIA reactions, for instance in cases with isolated antibody to NS5. From large clinical series, it appears that positive Riba serum profiles can be divided in two main groups: Strongly positive sera associate at least strong (3 or 4+) anti-capsid and anti-NS3 antibody reactivities. These profiles are often completed by anti-NS4 and/or anti-NS5 reactivities. Such profiles are associated with HCV viremia in about 90% of the cases. In this group, prevalence of viremia reaches 100% in patients with elevated level of serum alanin aminotransferase (ALT) and is slightly less frequent, 85%, in patients with normal level of ALT; Weakly positive sera lack either anti-capsid or anti-NS3 antibodies or exhibit only low reactivities (1+ or 2+) to these two antigens. These profiles can also be associated with antibodies to NS4 and/or NS5. Only 10% of patients with such Riba profiles are viremic. Weakly positive profile can be encountered during the early phase of HCV infection (recent seroconversion) or in patients who experience a favourable evolution of their HCV infection. Change of Riba profiles during follow-up provides fruitful information on recent seroconversions (increase in number and intensity of the reactivities). It can also help predict the outcome of HCV infection, a diminution of the intensity of Riba reactivities will confirm the extinction of viral replication.

Comparison of DNA enzyme immunoassay and line probe assays (Inno-LiPA HCV I and II) for hepatitis C virus genotyping

Two methods for genotyping hepatitis C virus (DNA enzyme immunoassay [DEIA] and line probe assay [Inno-LiPA HCV I and II]) were compared on 120 samples and of these 87% were assigned to the same subtype by both assays. There were 15 subtyping discrepancies which involved 5% of type 1 isolates and 90% of type 2 isolates. Amplified products from the core and 5' untranslated regions (UTR) were sequenced to resolve conflicts. Type 1 discordant samples had a guanosine at position -99 in the 5' UTR, a characteristic of genotype 1b, and a core region typical of subtype 1a. The eight isolates classified as 2a/2c by LiPA and as subtype 2c by DEIA belonged to type 2.

99mTc-MIBI uptake in a primitive leptomeningeal melanoma

Primitive leptomeningeal melanoma is a rare and aggressive condition. The authors report on a case of primitive leptomeningeal melanoma imaged with 99mTc-Sestamibi (MIBI). There was an intense accumulation of the radiotracer in the frontal and parietal leptomeningeal regions and even after injections of gadolinium the MRI continued to reveal a cystic image of the brain. In view of the diagnosis, MRI demonstrated only limited usefulness. On the other hand, this case highlights the important role of MIBI for the imaging of malignant tumors.

Bone formation and resorption biological markers in cosmonauts during and after a 180-day space flight (Euromir 95)

Long-term spaceflights induce bone loss as a result of profound modifications of bone remodeling, the modalities of which remain unknown in humans. We measured intact parathyroid hormone (PTH) and serum calcium; for bone formation, serum concentrations of bone alkaline phosphatase (BAP), intact osteocalcin (iBGP), and type 1 procollagen propeptide (PICP); for resorption, urinary concentrations (normalized by creatinine) of procollagen C-telopeptide (CTX), free and bound deoxypyridinoline (F and B D-Pyr), and Pyr in a 36-year-old cosmonaut (RTO), before (days -180, -60, and -15), during (from days 10 to 178, n = 12), and after (days +7, +15, +25, and +90) a 180-day spaceflight, in another cosmonaut (ASW) before and after the flight. Flight PTH tended to decrease by 48% and postflight PTH increased by 98%. During the flight, BAP, iBGP, and PICP decreased by 27%, 38%, and 28% respectively in CM1, and increased by 54%, 35%, and 78% after the flight. F D-Pyr and CTX increased by 54% and 78% during the flight and decreased by 29% and 40% after the flight, respectively. We showed for the first time in humans that microgravity induced an uncoupling of bone remodeling between formation and resorption that could account for bone loss.

[Is cerebral tomoscintigraphy with 99mTc-MIBI useful in the diagnosis of local recurrence in patients with malignant gliomas?]

PURPOSE

99mTc-MIBI, an alternative radiopharmaceutical for myocardial perfusion study has been proposed for use as a tumor imaging agent, including breast cancer, lung cancer, lymphomas, melanomas, and brain tumors. After routine radiation therapy, deteriorating clinical status or treatment failure may be due to either radiation changes or recurrent tumor. CT and MRI offer imperfect discrimination of tumor viability and radionecrosis.

MATERIALS AND METHODS

Thirty-five malignant glioma patients with clinical deterioration were studied retrospectively. Tomoscintigraphy was performed 15 minutes after intravenous injection of 1110 Mbq 99mTc-MIBI. The images were obtained from a dual headed gamma camera using fan beam collimator. Transverse, coronal and sagittal views were reconstructed.

RESULTS

A dramatic MIBI uptake was found in 31 patients. This uptake was correlated to tumor recurrence proven by histological fragments and/or the rapid, fatal evolution of these patients. Death occurred after the brain SPECT had been performed for those cases showing MIBI uptake, an average 5.48 months later. No MIBI uptake was found for these four remaining patients: their evolution can be currently considered to be a disease-free time.

CONCLUSIONS

According to our results, the sensibility and specificity of 99mTcMIBI brain SPECT seems to be high. Moreover, this investigation is more accurate for discriminating tumor recurrence from radionecrosis than a CT scan or MRI.