Modulation of NF-kappa B, and Bcl-2 in apoptosis induced by cisplatin in HeLa cells

Cisplatin exposure induces apoptosis in HeLa cells. Since the interaction of this drug with DNA produces reactive oxygen species, we performed an analysis of the oxidative stress-responsive factors AP-1 and NF-kappa B. Although AP-1 levels were not modified during cisplatin exposure, electrophoretic mobility shift assays demonstrated an increase in NF-kappa B DNA binding activity that correlated with a decrease of the inhibitory protein I kappa B alpha and a specific relocalization of c-Rel, as assessed by immunoblotting and immunofluorescence. No changes in the levels or localization of p65 were found. Interestingly, I kappa B alpha relocalized to the nucleus, probably in order to regulate the binding of specific complexes. This process was accompanied by a decrease of the antiapoptotic protein Bcl-2, and a relocalization of p53 protein to the nucleus. Since HeLa cells lost most of their p53 protein due to a specific E6-dependent degradation, cisplatin could be inhibiting this degradation, since the p53 total levels were not increased during the exposure to the drug.

Regulation of the Na+-dependent high affinity glutamate/aspartate transporter in cultured Bergmann glia by phorbol esters

The effects of phorbol 12-tetradecanoyl-13-acetate (TPA) and dibutyryl cAMP on the glutamate transport present in chick Bergmann glial cell (BGC) cultures were examined. TPA produced a significant decrease in [3H]-D-aspartate uptake, while dibutyryl cAMP treatment elicited a slight reduction in the transport. This effect was dose and time dependent and sensitive to staurosporine, a Ca2+/diacylglycerol-dependent protein kinase C (PKC) inhibitor. Long-term exposure of the culture to TPA results in a dramatic fall of the transporter activity and a decrease in the amount of the transporter protein. These findings suggest that PKC is involved in transport modulation and possibly in the regulation of the transporter gene expression.

[Refibrinolysis with r-tPA for thrombosis of the mitral prosthesis after an acute myocardial infarct]

We report the case of a 62-year-old patient with a mitral prosthesis hospitalized with an anterior acute myocardial infarction who was treated with r-tPA. Some days later, the patient had mitral thrombosis with heart failure. Because of the high risk of surgical intervention, he was successfully treated with a new dose of r-tPA.

Oral autopsy of unidentified burned human remains. A new procedure

Forensic dentistry plays an increasingly important role in medicolegal investigation and identification procedures. The oral examination may be difficult because of postmortem changes, especially those of carbonized corpses. We present a new technique of oral autopsy that includes a new means of access to the oral cavity designed for application on unidentified burned human remains. This technique preserves the facial configuration of the cadaver, allowing visual recognition by family members or other persons that is fundamental if the antemortem dental records do not exist or are not available. Also, this technique permits adequate work productivity by the forensic team members and can be used in difficult working conditions, such as mass-disaster scenarios.

Cost-utility analysis of paclitaxel in combination with cisplatin for patients with advanced ovarian cancer

The standard treatment for patients with advanced ovarian cancer (AOC) has been cyclophosphamide and cisplatin (CP). Recently, the results of a large randomized comparative trial demonstrated that the combination of paclitaxel and cisplatin (TP) provided a progression-free survival benefit of 5 months. In this study, a cost-utility analysis was performed from a Canadian health care system perspective to estimate the incremental cost-effectiveness of the TP combination. Twelve AOC patients who received treatment with TP were matched for age and disease stage on a 1-to-2 basis with a CP control. Total hospital resource consumption was then collected for all patients. Treatment preferences were estimated from a cohort of 20 patients and 40 healthy female volunteers using the time trade-off technique. The outcomes were then generated through a decision-analytic model. First-line treatment costs with TP were approximately fourfold greater on a per-cycle basis than the CP alternative (Can$1911 vs Can$459). When progression-free survival benefit and patient treatment preferences were incorporated into the analysis, the results of the decision model revealed an incremental cost between Can$12,000 and Can$24,000 per quality-adjusted progression-free year with the TP protocol. Even though the TP combination has a considerably higher drug acquisition cost, the results of the current analysis suggest that this new chemotherapy regimen does provide patients with substantial quality-adjusted progression-free survival benefit at a reasonable cost to the Canadian health care system.

Activation of p42 mitogen-activated protein kinase by glutamate in cultured radial glia

The effect of L-glutamate (Glu) and its structural analogs N-methyl-D-aspartate (NMDA), kainate (KA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA), on the activation of p42 mitogen activated protein kinase (MAPK) was examined in cultured chick radial glia cells, namely retinal Muller cells and cerebellar Bergmann cells. Glu, NMDA, AMPA and KA evoked a dose and time dependent increase in MAPK activity. AMPA and KA responses were blocked by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) whereas NMDA responses were sensitive to 3-[(RS)-2-carboxypiperazin-4-yl)]-propyl-1-phosphonate (CPP) indicating that the increase in MAPK activity is mediated by AMPA/low affinity KA and NMDA subtypes of Glu receptors. The present findings open the possibility of a MAPK cascade involvement in the regulation of Glu-induced gene expression in radial glia.

Headache, vomiting and diplopia

Images

The role of endothelium in the calcium-induced reduction of the contractile response of the rabbit aorta

1. Increase of Ca2+ concentration in the bath solution diminishes the contractile response of isolated rabbit aorta rings to alpha 1-adrenoceptor agonists and KCl. 2. In intact preparations the contractions of methoxamine and phenylephrine were maximal when a 0.3- to 0.6-mM Ca2+ bath solution was used, and those of KCl were maximal with a 2.5-mM Ca2+ concentration. 3. The contractions of methoxamine and phenylephrine also were decreased by increasing the Ca2+ concentration above 1.25 mM in disrupted endothelium preparations and in those incubated in indomethacin (10(-5) M), N omega-nitro-L-arginine methyl ester (10(-4) M), or methylene blue (10(-6) M). 4. High organ bath Ca2+ concentrations also caused a decrease in KCl contractions using endothelium-denuded and the treated preparations, the responses being similar with 1.25 mM and 2.5-mM Ca2+ in the methylene blue-treated preparations, whereas they were greater with 1.25 mM Ca2+ in the others.

Neurological disturbances and hyperdynamic shock in a patient with esophagocoloplasty

A 39-year-old man, with no history of alcohol intake, who had had an esophago-ileo-colo-gastroplasty with ileotransversostomy, developed diplopia, seizures, metabolic acidosis, and cardiac failure and finally refractory hyperdynamic shock. He died 20 h after admission to our intensive care unit from cardiocirculatory collapse. Postmortem results revealed low erythrocyte transketolase activity, which was increased by 22% by in vitro addition of thiamine diphosphate (TDP effect). Cerebral pathology showed the alterations of Wernicke's encephalopathy. We discuss the possible mechanisms of fatal cardiovascular collapse and the unusual presentation of a case without a history of alcoholic intake or clinical malnutrition.

Impact of the human immunodeficiency virus epidemic on detection of Mycobacterium isolates in a general hospital

The number of human samples processed in our mycobacteriology laboratory ranged from 148 per 1,000 admissions in 1988 to 263 per 1,000 admissions in 1995 (5.2% were positive). The human immunodeficiency virus (HIV)-positive population contributed 33.3% of all samples, 43.3% of all isolates, and 36% of all new patients. Given that the ratios of the total number of samples to the number of Mycobacterium-positive samples were 18.3:1 in HIV-positive patients and 28:1 in HIV-negative patients, efforts to reduce the laboratory workload should begin with the HIV-negative population.

NMDA receptors in cultured radial glia

The expression of the NMDA subtype of glutamate receptors was investigated by Western blot analysis and RT-PCR in cultured chick Bergmann and Müller glial cells. Using subunit-specific antibodies directed to the carboxy terminus of the rat NMDAR2A/B we detected the expression of the NMDAR2 subunit in both kinds of culture. The functional subunit of the NMDA receptor, NMDAR1, was detected by means of RT-PCR. These results, together with our previous functional characterization of NMDA receptors in radial glia, provide conclusive evidence for the expression of functional NMDA receptor/channels in Bergmann and Muller glia cells. Our findings strengthen the notion of a modulatory role of glial cells in synaptic transmission.

Excitatory amino acid receptors coupled to the phosphoinositide pathway in Bergmann glia

Glutamate (L-glu) receptors coupled to phosphoinositide hydrolysis in primary cultures of Bergmann cells from chick cerebellum were characterized biochemically and pharmacologically. Both ionotropic and metabotropic receptor agonists stimulated [3H] inositol phosphates accumulation in the following order of potency: QA > NMDA > L-glu > KA approximately QA > AMPA > > t-ACPD. QA showed a biphasic dose-response curve (EC50 = 0.07 and 53 microM), suggesting interaction with two populations of receptors; L-glu was the most efficient agonist. Stimulation by NMDA was blocked by CPP, AP5 and MK-801; that by AMPA and KA was inhibited 100% by CNQX and DNQX, whereas the effect of QA was decreased both by CNQX and the metabotropic antagonist 4-CPG. Stimulation of PIP2 hydrolysis induced by metabotropic L-glu receptor agonist t-ACPD was blocked by 4-CPG but was only moderately inhibited by MCPG. EAA-induced [3H]IPs accumulation was dependent on external Ca2+ and was not affected by nifedipine verapamil, or dantrolene; thapsigargin increased the effect. Results suggest that EAA activate the PI pathway in Bergmann glia through ionotropic (NMDA and AMPA/KA) as well as metabotropic receptor subtypes (t-ACPD) which could act jointly influencing neurotransmission at the parallel fiber-Purkinje cell synapses in the cerebellum.

Genotypic assessment of isoniazid and rifampin resistance in Mycobacterium tuberculosis: a blind study at reference laboratory level

Progress in understanding the basis of resistance to isoniazid (INH) and rifampin (RMP) has allowed molecular tests for the detection of drug-resistant tuberculosis to be developed. Consecutive isolates (n = 95) of Mycobacterium tuberculosis, from a Spanish reference laboratory investigating outbreaks of multidrug-resistant tuberculosis, were coded and sent to two external laboratories for genotypic analysis of INH and RMP resistance by PCR-single-strand conformation polymorphism (SSCP) analysis of specific regions of four genes: part of the coding sequence of katG and the promoter regions of inhA and ahpC for INH and the RMP resistance region of rpoB. After correction for the presence of outbreak strains and multiple isolates from single patients, RMP resistance was detected successfully by PCR-SSCP in > 96% of the RMP-resistant strains. PCR-SSCP had a sensitivity of 87% for INH resistance detection, and mutations in katG, inhA, katG-inhA, ahpC, and katG-ahpC were identified in 36.8, 31.6, 2.6, 13.2, and 2.6%, respectively, of the unique strains. Specificity was 100%. Molecular detection of resistance to the two main antituberculous drugs, INH and RMP, can be accomplished accurately by using a strategy which limits analysis to four genetic regions. This may allow the expedient analysis of drug resistance by reference laboratories.

A longitudinal study of transmission of tuberculosis in a large prison population

The purpose of this study was to determine the extent of transmission of tuberculosis in a large prison population over an 18-mo period. Restriction-fragment-length polymorphism (RFLP) analysis of isolates of Mycobacterium tuberculosis was performed, using the insertion sequence IS6110 and the plasmid pTBN12. Patients infected with strains having the same fingerprint were grouped in clusters. Medical records were reviewed and movement of inmates among prisons was examined for selected patients. Tuberculosis was diagnosed in 216 inmates (case rate = 2,283 per 100,000 per year). Isolates from 210 (97%) patients were fingerprinted, 155 (74%) were grouped in 25 clusters, and 55 (26%) showed a unique fingerprint. Recent infection was inferred in 62% of these patients. Eighty-four percent (161 of 192) of patients tested were human immunodeficiency virus (HIV)-positive, of whom 121 were in clusters and 40 were not (p = 0.74). Patients in clusters were less adherent with tuberculosis treatment than those not in clusters (p < 0.05), and prison transmission of resistant strains was observed. It is crucial that infection control guidelines be fully implemented in the prison setting to prevent tuberculosis transmission.

Effect of the organic Ca2+ channel blocker D-600 on sarcoplasmic reticulum Ca2+ uptake in skeletal muscle

Experiments were undertaken to study the possibility that the calcium channel blocker D-600 (gallopamil), which penetrates into muscle cells (20), facilitates excitation-contraction coupling in skeletal muscle (7) by a direct effect on the sarcoplasmic reticulum (SR). The effects of D-600 were studied on single phasic muscle fibers, either intact or split open. D-600 potentiated twitches in intact fibers at concentrations lower than those reported in whole muscles. In split fibers, the force produced by caffeine-induced Ca2+ release from the SR was reversibly inhibited by 5 microM D-600, when added to the Ca2+ loading solution. This inhibitory effect was inversely related to temperature, and it was dose dependent. When D-600 was added after Ca2+ loading and before caffeine exposure, or during the caffeine exposure itself, it did not inhibit Ca2+ release, but rather increased the development of force. We conclude that, apart from the blocking effect that D-600 may have on the voltage sensor, the drug penetrates into the myoplasm and affects excitation-contraction coupling by inhibiting the SR Ca2+ pump. This may be the consequence of a conformational change in the transmembrane Ca2+ binding domain of the ATPase.

Adaptive scalar quantization without side information

In this paper, we introduce a novel technique for adaptive scalar quantization. Adaptivity is useful in applications, including image compression, where the statistics of the source are either not known a priori or will change over time. Our algorithm uses previously quantized samples to estimate the distribution of the source, and does not require that side information be sent in order to adapt to changing source statistics. Our quantization scheme is thus backward adaptive. We propose that an adaptive quantizer can be separated into two building blocks, namely, model estimation and quantizer design. The model estimation produces an estimate of the changing source probability density function, which is then used to redesign the quantizer using standard techniques. We introduce nonparametric estimation techniques that only assume smoothness of the input distribution. We discuss the various sources of error in our estimation and argue that, for a wide class of sources with a smooth probability density function (pdf), we provide a good approximation to a "universal" quantizer, with the approximation becoming better as the rate increases. We study the performance of our scheme and show how the loss due to adaptivity is minimal in typical scenarios. In particular, we provide examples and show how our technique can achieve signal-to-noise ratios within 0.05 dB of the optimal Lloyd-Max quantizer for a memoryless source, while achieving over 1.5 dB gain over a fixed quantizer for a bimodal source.

Modulation of immune cell populations and activation markers in the pathogenesis of African swine fever virus infection

African swine fever (ASF) virus induces immune cell alterations that may be detected by changes in peripheral blood cells phenotypic antigens and activation markers which were examined by flow cytometry, analyzing both cell proportion and/or expression intensity of superficial antigens. These studies were conducted in pigs with experimental acute of chronic ASF infection to determine whether changes among important surface activation markers and phenotypic antigens, and their correlative lymph node status, reflected similar or disparate aspects of immune pathology. In acute infection produced by virulent viruses, macrophage and B lymphocyte populations decreased in peripheral blood after a short activation period at the beginning of the infection. A significative decrease of interleukin 2 receptor (IL 2R) expression was also observed in those pigs. These variations correlated with lymph node cell depletion due to an intense lymphoid cell death by apoptosis, affecting mainly the B lymphocyte subpopulation as determined by immunohistochemistry. Nevertheless, pigs infected with an attenuated isolate undergoing chronic persistent infection, presented a distinct pattern of modification, according with a different clinicopathological evolution. Changes consisted in systemic immune activation coincident with the highest viremia titer, with an augmentation in CD8+ T lymphocyte, macrophage, and B cell populations, and MHC (major histocompatibility complex) antigens. Percentage elevation of circulating immune subpopulations was accompanied by cell accumulation with lymphoid hyperplasia but a conserved distribution of B lymphocytes in lymphoid organs of chronically infected pigs.

[Tuberculous hepatosplenic abscess, human immunodeficiency virus infection and multiresistant tuberculosis]

BACKGROUND

Tuberculosis (TB) with liver and/or spleen abscess (HSA) formation in HIV-positive patients is uncommon.

PATIENTS AND METHODS

One hundred and thirty-seven HIV positive patients with TB were studied from January 93 to June 95. Patients with tuberculous HSA were enrolled in the study. Diagnosis was obtained by recovery of Mycobacterium tuberculosis in clinical specimens and the presence of hypoechogenic lesions in liver and/or spleen.

RESULTS

M. tuberculosis isolates were resistant to some of the usual drugs in 51 patients. Twenty of these patients had HSA (39%) and in 18 patients the antibiotic sensitivity testing showed resistance to isoniazid, rifampin, ethambutol, and streptomycin. The remaining 86 patients had episodes of TB with drug-susceptible microorganism and only three patients had HSA (3%) (p < 0.001). The 23 patients with tuberculous HSA had a mean CD4+ lymphocyte count of 33 x 10(6) cells/L (2-111) and 7 had a previous episode of TB. The abdominal echography showed hepatosplenomegaly in all cases. Abscesses were located at the liver in 12 patients (52%), spleen in 18 (78%) and both organs in 7 (30%). In 16 cases a corticosteroid therapy was indicated. In the 3 patients with susceptible TB and HSA the clinical course was good. The 20 patients with resistant TB died.

CONCLUSION

Abdominal TB in HIV-positive patients and HSA formation appears to be more common in severely immunosuppressed patients, with resistant TB and its mortality rate is high. The response to therapy with antituberculous drugs is slow and sometimes the administration of corticosteroids is necessary for the resolution of symptoms.

Apoptosis: a mechanism of cell killing and lymphoid organ impairment during acute African swine fever virus infection

Induction of programmed cell death has been described during infection with many different viruses. We have investigated the influence of African swine fever virus (ASFV) on apoptosis of different cell populations during in vitro and in vivo infection. We observed apoptosis in ASFV-infected monocyte/macrophage and peripheral blood mononuclear cell cultures. Apoptosis was demonstrated in these cells by DNA fragmentation, DNA staining and DNA-associated histone fraction detection assays. Flow cytometry analysis of infected cultures also showed morphological and functional alterations, including changes in the cell cycle and percentage of cell fractions stained with propidium iodide. After in vivo infection with three different virulent strains of ASFV, apoptosis of infected cells from the mononuclear phagocytic system and closely related elements from different tissues was observed. Additionally, infected pigs showed an intense degree of apoptosis of lymphocytes, which are not infected by the virus. In lymph nodes and other lymphoid organs, broad bands of apoptotic cells presented typical nuclear changes under light microscopy. The occurrence of DNA fragmentation was confirmed in these tissues using terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling. These findings, together with the pathological observations in infected pigs of a depletion in cell populations in lymphoid organs, suggest that virus interference with programmed cell death plays a central role in pathogenesis of this disease, being responsible for lymphoid organ impairment in acute ASFV infection.

Cholesterol increases the thermal stability of the Ca2+/Mg(2+)-ATPase of cardiac microsomes

The effect of membrane cholesterol on the thermal inactivation of Ca2+/Mg(2+)-ATPase activity of bovine cardiac microsome was measured and compared to the thermal denaturation profiles of the microsomes as measured by differential scanning calorimetry (DSC). Inactivation, defined as loss of activity, and denaturation, defined as conformational unfolding, were irreversible under the conditions used. Both thermal inactivation of Ca2+/Mg(2+)-ATPase activity and thermal denaturation were shifted to higher temperatures in microsomes enriched with cholesterol (37 +/- 5 micrograms cholesterol/mg protein, cholesterol/phospholipid molar ratio 0.31) compared to control microsomes (15 +/- 3 micrograms cholesterol/mg protein, molar ratio 0.12). Thermal inactivation was measured by two methods: first, measuring activity at room temperature as a function of heating to elevated temperatures at 1 K/min, where inactivation temperatures (T1, temperature of half activity) were 58.9 +/- 0.3 degrees C for control membranes and 59.9 +/- 0.1 degrees C for cholesterol-enriched membranes, respectively. Second, measuring ATPase activity as a function of time at constant temperature, where T1 values of 57.6 +/- 0.5 degrees C and 59.2 +/- 0.5 degrees C were determined for control and cholesterol-enriched membranes, respectively. DSC profiles of microsomal membranes consisting of a number of overlapping peaks were obtained. A well resolved component (transition C) was observed with a transition temperature (T 1/2) of 58.2 degrees C. This T 1/2, which is a measure of conformational stability, correlates with the T1 for Ca2+/Mg(2+)-ATPase activity and is 1.9 +/- 0.6 K higher in cholesterol-enriched membranes. Thus, the increased resistance to inactivation appears to be due to increased conformational stability of the protein induced by cholesterol, demonstrating that a change in lipid composition can influence the stability of an integral membrane protein in a natural membrane. The increased stability is of sufficient magnitude to account for the previously observed correlation between cholesterol content and resistance to heat shock in several cell lines.

Penetrating cardiac injuries

Penetrating cardiac injuries pose a tremendous challenge to any trauma surgeon. Time, sound judgment, aggressive intervention, and surgical technique are the most important factors contributing to positive outcomes. This article extensively reviews the history, surgical management, and techniques needed to deal with these critical injuries. This year commemorates the one hundredth anniversary of the first successful repair of a cardiac injury.

Membrane healing and restoration of contractility after mechanical injury in isolated skeletal muscle fibers of the frog

In single isolated skeletal muscle fibers of the frog, we studied (i) the recovery from large sarcolemmal mechanical injuries of the response to electric stimulation and (ii) the integrity of the sarcolemma under the light microscope. In Ringer's solution, the damaged cells stopped contracting and deteriorated completely within 1 hr. In the presence of phosphatidylcholine (0.025 g/ml in Ringer's solution), the injured cells initially responded with local twitches. Within 0.5 hr, contractility and membrane integrity started to recover and both were back to control levels within 3 hr. When these cells were placed back in normal Ringer's solution, they remained viable and active for several hours. Our results suggest that phosphatidylcholine can protect muscle fibers from the effects of sarcolemmal injury.

Effect of melatonin on beta-tubulin and MAP2 expression in NIE-115 cells

Physiological concentrations of the pineal hormone melatonin induce an increase of microtubules in neuroblastoma NIE-115 cells. This effect is due to an increase in the polymerization state of tubulin. Concomitantly, higher levels of soluble beta-tubulin are present in the treated cells. Unexpectedly, no significant changes in the levels of beta-tubulin or its mRNA occur in the presence of melatonin reflecting perhaps a strict control of its steady state in a physiological context. In contrast, higher amounts of microtubule-associated-protein 2 are found when the cells are exposed to melatonin. These findings support the idea that tubulin polymerization process is one of the targets of melatonin action. Furthermore, our results might explain the increase in the length and number of neurites present in these cells when they are treated with this hormone.

Tropism of human adenovirus type 5-based vectors in swine and their ability to protect against transmissible gastroenteritis coronavirus

The infection of epithelia] swine testicle and intestinal porcine epithelial (IPEC-1) cell lines by adenovirus type 5 (Ad5) has been studied in vitro by using an Ad5-luciferase recombinant containing the firefly luciferase gene as a reporter. Porcine cell lines supported Ad5 replication, showing virus titers, kinetics of virus production, and luciferase expression levels similar to those obtained in human 293 cells, which constitutively express the 5'-end 11% of the Ad5 genome. The tropism of Ad5-based vectors in swine and its ability to induce an efficient immune response against heterologous antigens expressed by foreign genes inserted in these vectors has been determined. Ad5 vectors replicate and express heterologous antigens in porcine lungs and mediastinal and mesenteric lymph nodes. Significant levels of heterologous antigen expression were also demonstrated in the small intestine (jejunum and ileum), but Ad5 replication in this organ was very poor, suggesting that Ad vectors undergo an abortive replication in the porcine small intestine. The tissues infected by Ad5 were dependent on the inoculation route. The oronasal route appeared to be best for inoculation of bronchus-associated lymphoid tissue infection, while the intraperitoneal route was best for gut-associated lymphoid tissue infection. Epithelial cells of bronchioles, macrophages, type II pneumocytes, and follicular dendritic cells were identified as targets for Ad5, while epithelial cells of the intestine were not infected by Ad5. Viruses with a deletion from 79.5 to 84.8 map units in the E3 region, with or without heterologous inserted genes, replicated to lower levels in porcine tissues than did wild-type Ad5. It was also shown that an Ad5 recombinant expressing the four antigenic sites (A, B, C, and D) of transmissible gastroenteritis coronavirus (TGEV) spike protein induced in swine immune responses which neutralized TGEV infectivity. In addition, porcine serum from Ad-TGEV-immune animals provide passive protection when mixed with fully virulent TGEV and orally administered to highly susceptible newborn piglets. These results taken together indicate that swine may be a good animal model for human Ad5 lung infection to aid in the evaluation of candidate adenovirus vaccines and that Ad5 may be suitable as a recombinant viral vaccine or for other applications in swine.

Entamoeba histolytica: involvement of pp125FAK in collagen-induced signal transduction

The interaction of Entamoeba histolytica trophozoites with collagen involves cell adherence, formation, and release of electron dense granules (EDGs) containing collagenase activity leading to the degradation of the bound protein. The binding is thought to be mediated by an "integrin-like" collagen receptor. Since the signal transduction mechanisms triggered by the collagen-trophozoite interaction are unknown, but clearly involve cytoskeletal organization, we decided to explore the role of protein tyrosine phosphorylation in this process. Collagen induces a time-dependent increase in the phosphorylation of several polypeptides migrating around 67 and 110 kDa. One polypeptide of the high-molecular-weight component was identified as a 125-kDa protein with very similar epitopes to the focal treatment was a 42-kDa polypeptide related to the mitogen activated protein kinase (MAPK) family. Our results suggest that tyrosine phosphorylation is involved in collagen signaling in amoebas and that pp125FAK and p42MAPK homologs may play an active role in turning on the genetic program that enables the parasite to invade its host.

Recognition and treatment of radpdly progressive periodontitis

Rapidly progressive periodontitis (RPP) affects adolescents and young adults. Plaque composition is about 75 percent gram-negative and 25 percent gram-positive microorganisms. In most cases of periodontal disease, the degree of destruction is related to the quantity of local irritants, but in the case of RPP, the amount of microbial deposits varies. Functional defects in the immune response system are believed to play an important role in RPP. Most patients require a combination of nonsurgical, antibiotic, and surgical treatment. The inverse-bevel periodontal-flap procedure is recommended when periodontal pockets extend apically to the mucogingival junction, and when bone defects are present.

Influence of the intake of fortified breakfast cereals on dietary habits and nutritional status of Spanish schoolchildren

A study was performed on the breakfast habits of 200 schoolchildren between 9 and 13 years of age. The subjects were classified into two groups: group C, children who consumed fortified breakfast cereals (65 boys and 35 girls), and group NC, children who did not (64 boys and 36 girls). The different dietary habits and the nutritional status of the two groups were analyzed. Haematological, biochemical, anthropometric, and dietary data were collected, the latter involving a 5-day food record. The children of the C group were found not only to have a more complete and nutritive breakfast, but also showed better dietary patterns for the rest of the day. Their lipid intake (% kJ) was lower and the carbohydrate intake (g/d and % kJ) higher than in the NC children. The intakes of thiamine, pyridoxine, folates, and beta-carotenes were also higher in group C. Better dietary habits were reflected in higher blood levels of some important compounds. Group C children had higher retinol, serum folate, and riboflavin levels than NC children. The percentage of children with hypercholesterolaemia (serum cholesterol > 4.5 mmol/l) was higher amongst those of the NC group: 37% as compared with 18% of the C children.

Changes in rat brain muscarinic receptors after inhibitory avoidance learning

It is widely accepted that cerebral acetylcholine is necessary for learning and memory, but little is known about the type of muscarinic receptors involved in these functions. To investigate this problem, [3H]-N-methyl-scopolamine which binds to different types of muscarinic receptors, [3H]-Pirenzepine an M1 receptor antagonist, and [3H]-Oxotremorine-M which binds mainly to M2 receptors, were used as ligands to look for possible changes in muscarinic receptor density in neostriatum (NEO), hippocampus (HIP), amygdala (AMY), and temporo-parietal neocortex (CTX), after testing for retention of inhibitory avoidance, trained with high or low footshock intensities. After low reinforcement there was an M1 postsynaptic receptor up-regulation in NEO, HIP, and CTX, and an M2 presynaptic receptor down-regulation in HIP, which suggests a concerted pre- and postsynaptic cholinergic activation in this area. An up-regulation of both M1 and M2 receptors was detected in CTX of low and high footshocked animals, which indicates the presence of a cortical postsynaptic M2 receptor.

Internucleosomal DNA cleavage in HeLa cells exposed to cisplatin

Exposure of HeLa cells to Cisplatin resulted in cell death characteristic of a suicide process known as apoptosis, as stated by morphologic features, extensive and specific DNA fragmentation and in situ end labeling of DNA breaks. The apoptotic cell death was induced timely in a dose-dependent manner, without any primary necrosis at the concentrations used. In contrast to other reports, the death in this cell line was accompanied by low-molecular weight DNA fragmentation. These results and their relevance to the apoptotic process are discussed.

[Nutritional health messages transmitted through television advertising. Trends and errors]

The present study analyzes de publicity messages with a alimentary-nutritional content (n = 448), aired by 2 television channels (one public and one private), during 6 hours a day in the first week of October 1993, examining the most frequent tendencies and errors, and whether or not they are adhering to the nutritional standards intended to improve the health of the population. With this aim, a questionnaire was designed, which was submitted to a control prior to doing the study, and which permitted the same study during the years 1991, 1992, and 1993. The message which was most used to promote the sales of the products, was the taste, followed by quality, novelty, health, nutritional and natural. The messages indicating that the product reduces or minimizes fat, cholesterol, sodium, sugar, alcohol, ... are few or lower than those observed in other populations. In some cases the messages may be useful in re-enforcing the standards of the nutritional educators and health care professionals who try to improve the diet and the health of the public. However, in the majority of cases, the message of the advertisements may mislead or confuse the consumer with irrelevant or incomplete information. They also frequently contribute to the promotion of an extremely thin body image, which guides the food choice of a large percentage of the population. The results of the study may help in the planning of nutritional education of the population, and they emphasize the need for a greater supervision and control of the advertisements.

Characterization of an Na(+)-dependent glutamate/aspartate transporter from cultured Bergmann glia

The properties of a transport system specific for L-glutamate and L-aspartate activity expressed in Bergmann glia cells from chick cerebellum were examined. The uptake of D-[3H]aspartate was inhibited by the endogenous substrates L-aspartate (Ki = 62 microM) and L-glutamate (Ki = 60 microM). Of the identified uptake inhibitors, L-aspartate-beta-hydroxamate (Ki = 900 microM), L-alpha-aminoadipate (Ki = 2000 microM), 4,4'diisothiocyanatos-tilbene-2,2'-disulphonic acid (DIDS) (Ki = 1000 microM) and 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulphonic acid (SITS) (Ki = 100 microM) inhibited D-[3H]aspartate uptake. Northern blot analysis, revealed the expression of a chick homologue of a the rat brain L-glutamate/L-aspartate transporter (GLAST). These data suggest that GLAST may be involved in the regulation of the parallel fibre-Purkinje cell synapse ensheathed by Bergmann glia.

Improvement of African swine fever virus neutralization assay using recombinant viruses expressing chromogenic marker genes

Antibody neutralization of African swine fever (ASF) virus measured by a plaque reduction assay presents frequent difficulties because of the absence or delay in plaque formation by many strains, especially low-passage viruses. To overcome this problem, a new ASF virus neutralization test has been developed. The new test consists of a conventional plaque reduction assay in which the viral plaques are detected by expression of marker genes. For the development of this neutralization assay 4 mutant viruses were generated by homologous recombination, containing beta-galactosidase or beta-glucuronidase reporter genes inserted into the thymidine kinase locus of the viral genome. These recombinant viruses have the following advantages with respect to parental viruses: (1) the neutralization assay takes less than a third of the time needed using non-recombinant viruses; (2) the small plaques can be detected more accurately by color contrast; and (3) the neutralization-resistant virus clones can be recovered easily post-plaque counting. Additionally, these recombinant viruses permit differentiation by chromogenic staining of individual infected pig macrophages, the natural host cell for ASF virus, facilitating neutralization assays in these primary cultures as described in cell lines.

Cost-evaluation model for clinical trials in a hospital pharmacy service

A cost-evaluation model was applied to clinical trial protocols to estimate their cost for the hospital pharmacy service. The steps taken in the drug management of clinical research were identified. Fixed costs (common to all clinical trials) and variable costs (peculiar to each clinical trial) were determined for each step. The number of patients, the number of operations, the planned services (receptions, storage, drug dispensing), the timing and difficulty of the study (randomization) were included in the variable costs. The economic assessment of these items was based on the costs of the materials and means used, the cost of staff time and finally the cost of drug storage during the clinical trial. This model was applied to 24 clinical trials carried out in the University Clinic of Navarra. 83% of all pharmacy costs of a clinical trial were variable. Drug dispensing, stock management and return drugs account for 94% of the time expended. The approximate cost of the pharmacy providing investigational services was $1,766 per trial or $174 per patient. Drug storage costs were not an important source of expenditure among the variable costs (7.4%). The best way to determine the cost of a trial is to calculate the number of operations.

Quantitation of intratumoral thymidylate synthase expression predicts for resistance to protracted infusion of 5-fluorouracil and weekly leucovorin in disseminated colorectal cancers: preliminary report from an ongoing trial

A clinical trial for patients with measurable, disseminated colorectal cancer is being conducted to determine: (1) if intratumoral expression of thymidylate synthase (TS) affects response to protracted-infusion 5-fluorouracil (5FU); and (2) whether intratumoral expression of TS increases when clinical resistance is found after response to 5-FU. Polymerase chain reaction technology is employed to determine TS expression. Using beta-actin as an internal standard, TS expressions for 26 patients range from 0.5 x 10(-3) to 22.6 x 10(-3). Currently, 22 patients are evaluable for response and TS quantitation of their measurable tumour. 8 patients (36%) have had partial responses; 3 responding patients had been previously treated with 5-FU. A strong statistical association between TS expression and resistance to therapy has been found (P = 0.004). No patient with TS expression of 4.0 x 10(-3) or greater has responded. On average, patients previously treated with 5-FU have slightly higher levels of TS expression in their measurable tumours (P = 0.4). Whether responding patients will develop increased expressions of TS upon clinical progression of their cancer remains to be determined. Confirmation of these results in a larger cohort could lead to a scientific rationale for deciding upon specific therapy for patients with disseminated colorectal cancers.

Excitatory amino acid-induced AP-1 DNA binding activity in Müller glia

The effect of L-glutamate (L-Glu) and its structural analogs N-methyl-D-aspartate (NMDA), quisqualate (QA), and kainate (KA) on the DNA binding activity of the Activator Protein 1 (AP-1) and the Ca2+/cAMP Responsive Element Binding Protein (CREB) families of transcription factors was examined in cultured chick retinal Müller glia cells. L-Glu, NMDA, and KA evoked a dose and time dependent increase in AP-1 DNA binding activity and had no effect on CREB binding. The order of potency for stimulating AP-1 DNA binding was NMDA > or = Glu > KA >> QA. L-Glu responses were partially blocked by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and by 3-[RS)-2-carboxypiperazin-4-yl)]-propyl-1-phosphonate (CPP) indicating that the increase in DNA binding is mediated both by an alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)/low affinity KA and a NMDA subtypes of L-Glu receptors. Since Müller glia L-Glu receptors are probably mediators of the efficacy of the excitatory transmission in the retina, the present findings suggest that a stimulus-transcription coupling triggered by L-Glu in the glial cells might have a role in the long-term modulation of these synapses.

Interaction of guanine nucleotides with the kainate binding protein from chick cerebellum

The interaction of guanine nucleotides with the chick cerebellar kainate binding protein (chKBP) was studied using binding assays, immunoblotting, and in vitro phosphorylation experiments. Guanosine 5'-triphosphate (GTP) was found to reduce [3H]kainic acid (KA) binding in a concentration-dependent manner. Similarly, an inhibition of [3H]GTP binding by KA was observed. No G protein co-purified with chKBP. chKBP phosphorylation by the cAMP-dependent protein kinase (PKA) was prevented both by KA and by GTP. Neither KA nor GTP blocked each other's effect in chKBP phosphorylation. The present findings suggest that chKBP harbours two agonistic binding sites, one in the micromolar range, detected by binding techniques and one in the millimolar range detected by phosphorylation assays. Guanine nucleotides interact with both sites.

Fecal diversion for penetrating colon injuries--still the established treatment

PURPOSE

An analysis of the existing literature on primary repair of colon injuries was undertaken to determine if there is sufficient evidence that this approach is superior to fecal diversion.

METHODS

After a thorough literature search, three prospectively randomized studies comparing primary repair with fecal diversion in the management of colon injuries were identified. A variety of factors were examined, including the number of patients in each study arm, morbidity rates, as well as exclusion criteria. An analysis was performed to determine the number of patients required to establish statistical superiority of one procedure over the other.

RESULTS

Pooling of the data contained in the aforementioned reports does not provide sufficient statistical power to support the superiority of primary repair of colon injuries. To demonstrate a 5 percent difference between the two approaches, a prospective, randomized study consisting of 200 patients in each arm is necessary.

CONCLUSION

The present literature does not support a statistically valid advantage of primary repair over fecal diversion in the management of traumatic colon injuries.

[Resistant tuberculosis in a prison population during 1991-1993]

BACKGROUND

To know the prevalence of resistant tuberculosis and the characteristics of the same in the penitentiary medium in the Madrid area (Spain).

METHODS

From March 1, 1991 to August 31, 1993 a prospective study was carried out in patients with isolations of Mycobacterium tuberculosis resistant to some of the common antituberculous drugs within the context of tuberculosis in a penitentiary population attended in the Hospital General Penitenciario (Madrid). Demographic, clinical, analytical, and microbiological data were collected as was that on the antituberculous treatment used. The study of sensitivities was performed by the proportions method.

RESULTS

Tuberculosis was diagnosed in 275 patients according to strict microbiological criteria (positive Löwenstein culture). The antibiogram was performed in 218 isolations. Twenty strains resistant to some first line antituberculous drug (9%) (confidence interval [CI] p < 0.05:6-14), 9 of which were found to be multiresistant, were detected in 20 patients. Out of the patients in whom the sensitivity of the isolate was known, 173 had not previously undergone antituberculous treatment. Six of these patients were found to be resistant to isoniazide (3.5%) (CI p < 0.05:1.4-7.7) and 2 patients were resistant to rifampicin (1.2%) (CI p < 0.5:0.2-4.5). The other 45 patients had previously undergone antituberculous drugs with 8 isolates presenting resistance to isoniazide and 11 to rifampicin. Eighty-four percent of the patients with resistant tuberculosis and 90% of the sensitive cases were coinfected with HIV infection with the differences not being statistically significant. The HIV positive patients with resistant tuberculosis showed a mean CD4 positive lymphocytes of 0.76 x 10(9)/l (CI p < 0.5:0.028-0.213) and those with sensitive tuberculosis had 0.165 x 10(9)/l (CI p < 0.05:0.133-0.196) (p < 0.01).

CONCLUSIONS

Tuberculosis resistant to common antituberculous drugs was detected in a Spanish penitentiary population. The level of the resistance of the isolations of Mycobacterium tuberculosis should be monitored both inside and outside of the penitentiary medium in an attempt to avoid the progression of resistant tuberculosis within the Community.

Use of thermal analysis to distinguish magnesium and calcium stimulated ATPase activity in isolated transverse tubules from skeletal muscle

The presence of calcium stimulated adenosine triphosphatase (Ca2+,Mg(2+)-ATPase) activity in isolated transverse tubule (t-tubule) membranes is distinguished from magnesium adenosine triphosphatase (Mg(2+)-ATPase) activity on the basis of differing thermal stabilities. The Mg(2+)-ATPase is the major protein component of the t-tubule membrane, and it can be difficult to discriminate between the low levels of Ca2+ stimulated ATPase activity found in isolates of t-tubules compared to the much higher Mg(2+)-ATPase activity. Thermal analysis reveals different inactivation temperatures (Ti) for the proteins responsible for ATP dependent calcium transport (Ti = 49 degrees C) and Mg(2+)-ATPase activity (Ti = 57 degrees C) in isolated t-tubule membranes. The differential scanning calorimetry profile of t-tubule membranes consists of three major components with transition temperatures (Tm) of 51 degrees C, 57 degrees C and 63 degrees C. Denaturation of the component with Tm = 57 degrees C correlates with inactivation of Mg(2+)-ATPase activity, and denaturation of the Tm = 51 degrees C component correlates with the inactivation of Ca2+,Mg(2+)-ATPase activity and calcium transport. The functions of the t-tubule membrane component or components that denature with Tm = 63 degrees C have yet to be identified. The lack of stimulation of calcium transport in isolated t-tubules by oxalate, the impermeability of isolated t-tubules to oxalate, and experiments performed on t-tubules with defined amounts of sarcoplasmic reticulum (SR) added suggest that contamination of the isolated t-tubules by SR is unlikely to account for the level of Ca2+,Mg(2+)-ATPase activity detected. The presence of a Ca2+,Mg(2+)-ATPase in the t-tubule membrane would provide a mechanism that may be involved in the partial removal of calcium that is accumulated in the junctional space during muscle relaxation or calcium that is released from the terminal cisternae of sarcoplasmic reticulum during excitation-contraction coupling.

Laparoscopic management of complications of peptic ulcer disease

Laparoscopic treatment of intractable duodenal ulcers is intended for the treatment of patients who do not heal after a trial of intensive regimen of medication such as H2 blockers and/or therapy aimed at eradication of Helicobacter pylori. Patients in a category who are Helicobacter-negative can be offered a laparoscopic treatment of their ulcer by vagotomy. Patients who have early relapses on stopping medical treatment are also candidates for vagotomy. Complications of the disease, such as bleeding or pyloric outlet obstruction, represent valid indications in 1995 for performing surgery in patients with duodenal ulcer disease.

Laparoscopic splenectomy

Several indications for laparoscopic splenectomy are represented mainly by hematological disorders such as Idiopatic Thrombopenic Purpura (ITP) or hereditary spherocytosis. Patients with ITP who do not respond, have relapses of the disease under steroid treatment, or need a gradually increased dose of steroids, represent an excellent indication for laparoscopic splenectomy, as the spleen is not enlarged. Patients are usually small, thin, young females, making the procedure much easier. The size of the spleen in hereditary spherocytosis varies, sometimes making the procedure a little more difficult, especially as those patients have pigmented gallbladder stones necessitating a concurrent laparoscopic cholecystectomy. Other indications are represented by staging of Hodgkin's disease, lymphoma of the spleen, and splenic infarcts without abscesses. Some patients with autoimmune hemolytic anemia might benefit from laparoscopic splenectomy, but hypersplenism due to cirrhosis is strongly contraindicated, as the risk of intraoperative hemorrhage is great and not usually managed easily laparoscopically.