Epigenetic modulation of differentiation in CE44 teratocarcinoma

Teratocarcinoma is a mixed germ cell tumor histologically composed of embryonal carcinoma cells and embryonic and extraembryonic tissues. In the present work we have used the CE44 teratocarcinoma, which is a tumor cell line derived from the OTT6050 experimental tumor, to appreciate the influence the microenvironment has on the modulation of tumoral differentiation. For this, we have studied the development of CE44 teratocarcinoma in primary tumors (subcutaneous and intrasplenic) and in experimental metastases (hepatic and pulmonary). CE44 teratocarcinoma shows variations in its capacity for differentiation in so far as development is concerned and, in hepatic metastases, we noticed a reparative process of the intratumoral necrotic areas which in the same cases were substituted by loose connective tissue. Our results clearly suggest that the microenvironment is decisive in the biological behaviour of the teratocarcinoma cells and that epigenetic factors influence the capacity for differentiation of the undifferentiated tumoral cells.

Craniopharyngioma in children. Surgical treatment by a transbasal anterior approach

The authors present two cases of giant, ossified, craniopharyngioma in paediatric patients; one was subtotally (more than 90%) and the other, totally resected, both by a transfrontal-nasal approach. The results have been excellent, with total clinical recovery, olfactory function preserved and no cosmetic sequelae.

Corynebacterium kroppenstedtii sp. nov., a novel corynebacterium that does not contain mycolic acids

A strain of a hitherto undescribed coryneform bacterium from human clinical material was characterized by phenotypic and molecular taxonomic methods. Comparative 16S rRNA gene sequence analysis demonstrated the strain represents a novel and deep lineage within the genus Corynebacterium sensu stricto. Chemical analyses revealed the unidentified strain was unusual in that it lacked mycolic acids. Based on the phylogenetic and phenotypic distinctiveness of the unknown isolate, it is proposed that the bacterium be classified as a new Corynebacterium species, for which the name Corynebacterium kroppenstedtii sp. nov. is proposed. The type strain is CCUG 35717T.

Functional recovery and social outcome after cerebral infarction in young adults

This study was designed to assess the return to work, the poststroke depression and the quality of life after a cerebral infarction in young adults and was conducted on 71 consecutive young patients (aged 15-45 years) affected by a cerebral infarct who were hospitalized for the first time and discharged at least 1 year before the study. Data about risk factors, etiology, side and territory of stroke, social characteristics of the patient (age, sex, profession, educational level, family situation), poststroke seizures, recurrent stroke, other vascular events, and deaths were collected. Neurological deficits were graded with the National Institutes of Health (NIH) Stroke Scale. Poststroke depression (PSD) was quantified using the DSM-IIIR criteria and the Montgomery Asberg Depression Rating Scale. Outcomes were rated with the Ranking Scale, the Barthel Index and the Glasgow Outcome Scale. Quality of life was assessed with the Sickness Impact Profile. Follow-up information was obtained by interview and neurological examination. Follow-up information was obtained in 65 patients at a mean of 31.7 +/- 13.0 (range 12-59) months, as 2 patients died and 4 were lost to follow-up and were thus excluded from this study. Poststroke seizures occurred in 7 patients (10.8%) and recurrent strokes in 4 patients (6.2%), but none were fatal. The outcome after stroke among survivors was usually good, since more than two-thirds of the patients (69.8%) reported no problem, 11.1% moderate handicap and one-fifth major handicap. Forty-six patients (73%) returned to work: the time period ranging from several days after stroke to 40 months, with a mean of 8 months. However, adjustments in their occupation were necessary for 12 patients (26.1%). PSD was common, since 48.31% of the patients were classified as depressed. PSD was associated with the localization of the infarct (carotid territory), a severe disability, a bad general outcome, and an absence of return to work. Their opinion about their quality of life was negative among approximately 30% of the patients, especially in emotional and alertness behaviors. social interaction, recreation and pastimes. The general outcome after cerebral infarct in young adults is usually good. However, the risk of a PSD is high, and only half of the patients had returned to their previous work. A remaining psychosocial handicap and depression of sexual activity impaired the quality of life. In multivariate analysis, a low NIH score at admission is a significant predictor for return to work, the absence of PSD, and a good quality of life.

Neuroprotective role of S12024 against neurodegeneration in the rat dentate gyrus

We assessed the neuroprotective capabilities of S12024 (R,S 1-methyl 8-(2-morpholinylmethoxy)-1,2,3,4-tetrahydroquinoleine methane sulphonate) in a model of neuronal degeneration in the dentate gyrus of the rat hippocampus. Specific degeneration of a large part of neurons in the lateral blade of the gyrus dentatus occurred after small intrahippocampal injections of water with or without amyloid-beta 1-28 fragment. S12024 reduced the number of animals with neuronal loss in the hippocampus, diminished the extent of the lesion, and reversed deficits of passive avoidance learning acquisition in animals with deposits of amyloid-beta 1-28. These results suggest that S12024 has neuroprotective effects on hippocampal cells and that the neurodegeneration by fluid injection combined with deposit of amyloid-beta 1-28 may be used to assay the neuroprotective activity of pharmacological compounds.

Polyploidization and exit from cell cycle as mechanisms of cultured melanoma cell resistance to methotrexate

Numerous malignant neoplasias are found to contain varying proportions of high-ploidy cells. Although the role they play in the tumor is poorly understood, several lines of evidence suggest that these cells could be especially resistant to various aggressions, a possibility of great interest in cancer treatment. In the present study, we tested this hypothesis through the analysis of the presence of high-ploidy cells following the administration of the chemotherapeutic agent methotrexate. We also determined the expression of two proliferation markers, PCNA and CDK1, after methotrexate-treatment. Cultured cells from the murine melanoma B16F10 were treated with high doses of methotrexate for seven days prior to determination of DNA content and proliferation markers. Our results showed an obvious increase in the mean ploidy of this population. Specifically, there was a dramatic reduction in the proportion of tetraploid cells (predominant in the original population), and an increase in the proportion of cells with higher ploidies, particularly those whose DNA content was greater than 8c, including some cells with ploidies greater than 16c. Furthermore, there was a reduction in the number of PCNA-expressing cells and the reduction was much more marked in the case of CDK1 that was almost absent in the modal-ploidy treated cells. These alterations concerning ploidy and expression of proliferation markers had completely reverted two weeks after withdrawal of the drug. Our results indicate that methotrexate at a high dosage selects a cell population heterogeneous concerning its ploidy level, composed of one subpopulation of high-ploidy cells and another of modal-ploidy cells that, considering its lack of CDK1 expression, would remain in a latent state to evade the effects of the drug.

Plasticity of Congo red staining displayed by subpopulations of neurons within the rat central nervous system

We document the presence of subpopulations of neurons within the rat central nervous system that are labelled with a new Congo red staining technique. These neurons (CR neurons) show shrunken somata, and smaller and darker nuclei than Congo red-negative cells (non-CR cells). With the Bielschowsky and the cresyl violet Nissl staining methods, two comparable subpopulations of cells can be distinguished by the same morphometrical criteria as those used for CR and non-CR cells. CR neurons are located preferentially in some brain regions while in others they are virtually absent. Their distribution and proportion varied greatly from animal to animal and after particular treatments. Injections of water that damaged the hippocampal dentate gyrus, cortical lesions or eye enucleation decreased the number of CR-cells in the CA1 subfield, reflected in a shift from the CR-staining subclass to the non-CR subclass. Treatment with 200 mg/kg of CDP-choline also significantly reduced the number of CR cells observed in CA1. In the red nucleus, CR neurons showed a characteristic distribution of beta-amyloid precursor protein (APP) immunoreactivity. The population of dendrites immunolabelled for microtubule-associated protein 2 was markedly decreased in the areas of the hippocampus with high numbers of CR cells. Therefore, it is proposed that neurons labelled with the present Congo red technique might be in a reversible degenerative state or represent a particular physiological state in some areas of the central nervous system.

Prospective study for the detection of Anaplasma marginale Theiler, 1911 (Rickettsiales: Anaplasmataceae) in Costa Rica

A prospective study was conducted to assess the dynamics of the infection and host response to Anaplasma marginale in one closed herd in the dry tropical forest of Costa Rica. The study subjects were the dams and their calves born during 1 breeding season (1995-1996). All cows were sampled at 3 month intervals for antibody detection using a competitive ELISA (cELISA) and for antigen detection using PCR/nonradioactive probe assay. All 24 calves born during the study were individually identified at birth and subsequently sampled each month for PCR and cELISA. Ticks were identified from all animals throughout the entire study period. The results from this study confirmed that the cELISA is a reliable assay for identifying new and carrier infections and that carrier infections can exist at levels below that detectable by PCR. In addition, it was demonstrated that calves born in this region will most likely be exposed to Anaplasma within the first 6 months of age.

[Subarachnoid hemorrhage: electrocardiographic, left ventricular wall motion abnormalities and mortality analysis in 14 cases]

BACKGROUND

Electrocardiographic (ECG) changes have been frequently observed in patients with subarachnoid hemorrhage (SAH). Their association with wall motion abnormalities of the left ventricle (LV) have not been well established.

PATIENTS AND METHODS

Sixteen patients with SAH were included; 2 patients with previous history of heart disease were subsequently excluded. We studied the neurological damage (Hunt-Hess grading scale), ECG (ST segment, T wave) and echocardiography (LV regional and global contractility) of 14 patients.

RESULTS

The ECG was abnormal in 11 patients (T wave: 6 patients; ST segment: 5 patients). Echocardiography showed alterations in 5 patients, all of them with ECG changes (T wave: one patient; ST segment: 4 patients). The neurological lesion was higher in patients with abnormal echocardiogram (Hunt-Hess mean grade: 4.6 vs 2.7 in patients with normal echocardiogram; p < 0.001). An intravenous infusion of dobutamine in a 23 years old male, improved the LV ejection fraction, which was severely depressed at baseline. Mortality, in all cases secondary to the neurological damage, was higher in patients with abnormal ECG (91% vs 0% in patients with normal ECG; p = 0.01) and when the echocardiogram showed alterations although in the last case no statistical differences were found.

CONCLUSIONS

Echocardiography abnormalities in patients with SAH and without previous history of heart disease are more frequently related to ECG changes affecting ST segment, and to a higher cerebral damage.

Expression in Escherichia coli of the lpdA gene, protein sequence analysis and immunological characterization of the P64k protein from Neisseria meningitidis

By making use of recombinant DNA technology it is possible to characterize meningococcal outer membrane proteins (OMPs) capable of stimulating a host immune response. The lpdA gene, which codes for an OMP (P64k) from Neisseria meningitidis, was cloned in Escherichia coli. The recombinant protein was recognized by sera from patients convalescing from meningococcal disease. The monoclonal antibodies obtained against the recombinant protein recognized the natural protein on a Western blot, and monoclonal antibody 114 was assayed in ELISA with a panel of 85 N. meningitidis strains. The protein was recognized in 81 strains (95.3%); the strains that were not recognized were neither epidemic nor isolated from systemic disease. The complete amino acid sequence of P64k was obtained by automatic sequencing and MS.

Involvement of interleukin-6 in the biology and metastatic activity of B16F10 melanoma cells

In previous studies, we demonstrated the presence of the interleukin-2 (IL-2) signalling system in B16F10 murine melanoma and observed that in vitro treatment of B16F10 cells with IL-2, enhanced metastasis. To further understand the role played by interleukins in melanoma, we examined the effect of IL-6 on the metastatic activity and properties of B16 melanoma cells. We observed that B16F10 cells, cultured in the presence of IL-6, showed a clear increase in their metastatic ability, both in the liver and in the lungs. Neither cell proliferation nor in vitro colony formation were affected by IL-6; however, the expression of CD44 and VLA-4 increased. The IL-6 gene was expressed in B16F10 cells as shown by RT-PCR. A slight induction of IL-6 mRNA expression by IL-2 was observed, but not after treatment with IL-1beta or IL-6. Nevertheless, no soluble IL-6 could be detected in cell supernatants even after treatment with IL-2. Finally, we tested the effect of IL-1beta, IL-6 and IL-2 on the expression of the IL-2 receptor (IL-2R). IL-1beta turned out to be the strongest inducer of IL-2R expression in B16F10 cells. Altogether, these data confirm the involvement of interleukins in the biology and metastatic activity of melanoma.

Stable complexes involving acetylcholinesterase and amyloid-beta peptide change the biochemical properties of the enzyme and increase the neurotoxicity of Alzheimer's fibrils

Brain acetylcholinesterase (AChE) forms stable complexes with amyloid-beta peptide (Abeta) during its assembly into filaments, in agreement with its colocalization with the Abeta deposits of Alzheimer's brain. The association of the enzyme with nascent Abeta aggregates occurs as early as after 30 min of incubation. Analysis of the catalytic activity of the AChE incorporated into these complexes shows an anomalous behavior reminiscent of the AChE associated with senile plaques, which includes a resistance to low pH, high substrate concentrations, and lower sensitivity to AChE inhibitors. Furthermore, the toxicity of the AChE-amyloid complexes is higher than that of the Abeta aggregates alone. Thus, in addition to its possible role as a heterogeneous nucleator during amyloid formation, AChE, by forming such stable complexes, may increase the neurotoxicity of Abeta fibrils and thus may determine the selective neuronal loss observed in Alzheimer's brain.

Necrogenic and regenerative responses of liver of newly weaned rats against a sublethal dose of thioacetamide

The hepatocellular necrogenic and regenerative responses of newly weaned rats (21 days old) to a sublethal dose of thioacetamide (6.6 mmol kg-1) were studied in comparison to adult (6-month old rats), in terms of liver injury, antioxidant defense systems and cell proliferation. Hepatocellular necrosis, detected by serum aspartate aminotransferase, was less severe in newly weaned rats than in adult animals and was parallel to previous changes in the activity of microsomal FAD monooxygenase system responsible for thioacetamide biotransformation. Liver damage in hepatocytes from newly weaned rats was also detected by the decreased levels of glutathione and protein thiol groups (47%, p < 0.001 and 52%, p < 0.001 vs. untreated, respectively) and by the enhanced malondialdehyde production (334%, p < 0.001) and glutathione S-transferase activity (384%, p < 0.001). No significant differences were detected in these values when compared to adults. Changes in cytosolic and mitochondrial superoxide dismutase and catalase activities in hepatocytes from newly weaned rats at 24 h, following thioacetamide (49%, p < 0.001; 50% and 53%, p < 0.001 vs. untreated, respectively), were less severe against those in adult hepatocytes at 48 h of intoxication, and the increases in glutathione peroxidase and glutathione reductase activities were significantly lowered: 25% (p < 0.001) and 41% (p < 0.001), respectively. Post-necrotic DNA synthesis in hepatocytes from newly weaned rats peaked at 48 h of intoxication, while in adults a more intense peak appeared at 72 h preceded by a sharp decrease in tetraploid population. These differences indicate that the lower necrogenic response against the same dose of thioacetamide in newly weaned rats may be due to the lower rate of thioacetamide biotransformation and to the earlier onset of cell division. Accordingly, the growing liver from newly weaned rats presents advantages against the necrogenic aggression of thioacetamide, first, because the diminished activity of its specific microsomal detoxification system, and second because the earlier increase in the proliferative response prevents the progression of injury permitting an earlier restoration of liver function.

The distinctive headache of the occipital condyle syndrome: a report of four cases

Four examples of occipital condyle syndrome, that is, unilateral occipital pain and ipsilateral tongue paralysis due to selective erosion of the occipital condyle, are reported. The four patients complained of a continuous, severe, unilateral, occipital pain which kept them with the head rotated to the side of the pain and held with their hands. The pain became unbearable with head rotation to the nonpainful side and with unilateral suboccipital palpation. The onset of this very characteristic unilateral headache antedated by as long as 2 1/2 months the ipsilateral hypoglossal paralysis. The occipital condyle syndrome may be the first manifestation of cancer or of chronic inflammatory lesions; recognition of this distinctive headache enables the clinical diagnosis to be made.

Decelerating flow ventilation effects in acute respiratory failure

PURPOSE

The purpose of this article is to analyze the effect of a pressure-regulated volume-controlled ventilation mode on lung mechanics and gas exchange in patients with acute respiratory failure.

MATERIALS AND METHODS

We ventilated 10 patients with two pressure-limited modes: pressure-controlled ventilation (PC) and pressure-regulated volume-controlled ventilation (PRVC) in random order, for 1 hour each. Patients were stabilized on volume-controlled ventilation (VC) for 30 minutes before, between, and at the end of PC and PRVC to reach baseline conditions. At the end of every VC period and at 30 and 60 minutes of PC and PRVC, respiratory mechanics, gasometrics, and hemodynamic parameters were collected.

RESULTS

We found no significant differences between the three VC periods. Comparing VC with the two pressure-limited ventilation modes, peak pressure decreased from 29.4+/-9.1 cm H2O (VC) to 25.9+/-8.4 (PC 60 minutes) and 26.1+/-8.2 (PRVC 60 minutes), and PaCO2 decreased significantly from 38.6+/-3.1 mm Hg (VC) to 36.7+/-2.8 (PC 60 minutes) and 36.8+/-2.9 (PRVC 60 minutes).

CONCLUSIONS

Pressure-limited ventilation allows mechanical ventilation for the same tidal volume as VC but results in a lower peak inspiratory pressure and a slightly lower PaCO2. The mechanism responsible for this gas exchange effect is unknown but is probably related to a better air distribution of the decelerated flow. The clinical relevance of this phenomenon remains to be established.

Laminin blocks the assembly of wild-type A beta and the Dutch variant peptide into Alzheimer's fibrils

Amyloid fibril formation is believed to be a nucleation-dependent polymerization process which may be influenced by various other factors with important consequences for the development, prevention or treatment of amyloidosis. We have previously shown that laminin inhibits A beta peptide fibril formation in vitro. Here we present a kinetic study that indicates laminin to be a potent anti-amyloidosis factor, as it not only inhibited A beta 1-40 fibril aggregation, but also inhibited the aggregation of the Dutch A beta 1-40 variant, a peptide with a higher capacity to aggregate than the wild-type A beta 1-40. The inhibitory effect of laminin on amyloid fibril formation was not overcome by the addition of pre-formed A beta fibrils, suggesting that laminin inhibits the fibril elongation process. At the present time, however, we cannot rule out the possibility that laminin also affects the initial nucleation process of A beta fibril formation. On other hand, laminin was not able to counteract the amyloid fibril formation promoted by acetylcholinesterase (AChE), another component of the amyloid deposits found in AD brains. The effect of laminin may be important as an inhibitor of A beta amyloidogenesis in vivo, specifically at the level of cerebral blood vessels.

Flow cytometric studies of nucleoside transport regulation in single chromaffin cells

The present paper reveals that a fluorescent derivative of nitrobenzylthioinosine, 5-(SAENTA-x8)-fluorescein, is a highly specific inhibitor of the neural NBTI-sensitive nucleoside transporter. 5-(SAENTA-x8)-fluorescein inhibited adenosine transport and [3H]NBTI binding with a Ki of 4 nM in cultured chromaffin cells. Flow cytometry demonstrated that 5-(SAENTA-x8)-fluorescein specifically interacted with the NBTI-sensitive nucleoside transporters with high affinity (K[D] = 6 nM). Activation of protein kinases A and C with forskolin or nicotinic receptor agonists, respectively, resulted in 50% inhibition of the fluorescence bound to the cells. Flow cytometry will allow studying nucleoside transport in single cells from heterogeneous neural cell populations.

Brain acetylcholinesterase promotes amyloid-beta-peptide aggregation but does not hydrolyze amyloid precursor protein peptides

It has been suggested that acetylcholinesterase (AChE) has both a putative proteolytic activity against the amyloid precursor protein (APP), and a capacity to accelerate the assembly of amyloid-beta-peptide (Abeta) into Alzheimer's fibrils. Here, we have studied the ability of bovine brain AChE to share both activities. Results indicate that AChE purified through acridinium was able to process the APP peptides, however after further purification by an edrophonium column, the protease activity was lost. Under both conditions the capacity of the enzyme to promote amyloid formation was maintained. Kinetic studies of the Abeta aggregation process using edrophonium-AChE, indicated that the lag phase of the aggregation process was smaller than the one observed with the esterase purified by acridinium alone. Considering that the total amount of amyloid formed, measured by thioflavine-T fluorescence, was similar for both AChE preparations, our results suggest that the edrophonium-AChE possesses an higher intrinsic capacity to stimulate the aggregation of Abeta(1-40) peptide.

[Safety and efficacy of OM-85-BV plus amoxicillin/clavulanate in the treatment of subacute sinusitis and the prevention of recurrent infections in children]

A 6-month double-blind, prospective, randomized, placebo-controlled trial was conducted to establish the safety and efficacy of OM-85-BV in the treatment of subacute sinusitis and in the following prevention of the respiratory tract infections in 56 children from 18 months to 9 years of age. In the subacute phase of the sinusitis the patients were given one OM-85-BV capsule (3.5 mg of bacterial extracts) (n = 26) or placebo (n = 30), daily for ten days; additionally both groups took amoxicillin/clavulanate 40/10 mg/kg daily in three divided doses for 21 days. For the following two months the patients took one OM-85-BV capsule or placebo, ten days a month. In the subacute phase the OM-85-BV group of patients improved sooner (5.56 +/- 4.98 vs 10 +/- 8.49 days) and had a shorter convalescence (15.38 +/- 8.91 vs 20.28 +/- 7.17 days). During the six month follow-up the patients in the OM-85-BV group had a lower number of infections (1.56 +/- 0.3 vs 2.22 +/- 0.43) and required a lower number of drug treatments (1.47 +/- 0.32 vs 1.94 +/- 0.42). One patient treated with OM-85-BV presented a mild rash which disappeared three days after the drug discontinuation. We conclude that OM-85-BV is safe at pediatric ages, as well as accelerates the cure and improvement of subacute sinusitis while it lowers the incidence of respiratory infections.

Detection of antibodies to Candida albicans germ tubes for diagnosis and therapeutic monitoring of invasive candidiasis in patients with hematologic malignancies

We prospectively investigated the ability of detection of antibodies to Candida albicans germ tubes (CAGT) to diagnose invasive candidiasis in 95 consecutive admissions of 73 patients with hematologic disorders undergoing intensive chemotherapy. The episodes were divided into three groups according to clinical and microbiological diagnosis. Group 1 comprised eight admissions of eight patients with invasive candidiasis. Group 2 comprised 42 admissions of 34 patients without evidence of invasive candidiasis. Group 3 comprised the remaining 45 admissions of 37 patients with febrile episodes which were not diagnosed by microbiological culture. Antibodies to CAGT were detected in 87.5% of group 1 patients. Detection of antibodies to CAGT in patients with Candida fungemia was delayed somewhat relative to the time the blood culture was positive, but antibodies to CAGT were detected earlier than a diagnosis was made in patients with deep-tissue candidiasis. Sera from 2 admissions in group 2 and 12 admissions in group 3 revealed antibodies to CAGT. At a titer of > or = 1:20, detection of antibodies to CAGT had a sensitivity of 87.5%, specificity of 95.2%, positive predictive value of 77.8%, and negative predictive value of 97.6%. Antibodies to CAGT were usually detected before beginning of empiric antifungal therapy. Titers of antibodies to CAGT were maintained in most patients who died but declined and eventually disappeared in the patients who survived. Since antibodies to CAGT were detected in all patients with tissue-proven invasive candidiasis but negative by blood culture, detection of antibodies to CAGT complemented blood cultures for diagnosis and therapeutic monitoring of patients with hematologic malignancies and invasive candidiasis.