Needlestick injuries in a tertiary care centre in Mumbai, India

Accidental exposure from blood/body fluid of patients is a risk to healthcare workers (HCWs). Percutaneous injury is the most common method of exposure to blood-borne pathogens. A policy was formulated at our institute, a tertiary care centre in central Mumbai, and we report a six-year (1998--2003) ongoing surveillance of needlestick injuries. Of the 380 HCWs who reported needlestick injuries, 45% were nurses, 33% were attendants, 11% were doctors and 11% were technicians. On source analysis, 23, 15 and 12 were positive for Hepatitis B surface antigen (HBsAg), human immunodeficiency virus (HIV) and hepatitis C virus (HCV), respectively. Immediate action following potential exposure included washing the wound with soap and water, encouraging bleeding and reporting the incident to the emergency room. Analysis of the source of injuries revealed that known sources accounted for 254 injuries, and unknown sources from garbage bags and Operating Theatre instruments accounted for 126 injuries. Most needlestick injuries occurred during intravenous line insertion (N=112), followed by blood collection (N=69), surgical blade injury (N=36) and recapping needles (N=36). Immediate postexposure prophylaxis (PEP) for HCWs who sustained injuries with hepatitis-B-virus-positive patients included booster hepatitis B immunization for those positive for antiHBs. A full course of immunization with hepatitis B immunoglobulin was given to those who were antiHBs negative. All staff who sustained injury with HIV were given immediate antiretroviral therapy (AZT 600 mg/day) for six weeks. Subsequent six-month follow-up showed zero seroconversion.

Noise-induced annoyance and morbidity results from the pan-European LARES study

Traffic noise (road noise, railway noise, aircraft noise, noise of parking cars), is the most dominant source of annoyance in the living environment of many European countries. This is followed by neighbourhood noise (neighbouring apartments, staircase and noise within the apartment). The subjective experience of noise stress can, through central nervous processes, lead to an inadequate neuro-endocrine reaction and finally lead to regulatory diseases. Within the context of the LARES-survey (Large Analysis and Review of European housing and health Status), noise annoyance in the housing environment was collected and evaluated in connection with medically diagnosed illnesses. Adults who indicated chronically severe annoyance by neighbourhood noise were found to have an increased health risk for the cardiovascular system and the movement apparatus, as well as an increased risk of depression and migraine. Furthermore adults with chronically strong annoyance by traffic noise additionally showed an increased risk for respiratory health problems. With regards to older people both neighbourhood and traffic noise indicated in general a lower risk of noise annoyance induced illness than in adults. It can be assumed that the effect of noise-induced annoyance in older people is concealed by physical consequences of age (with a strong increase of illnesses). With children the effects of noise-induced annoyance from traffic, as well as neighbourhood noise, are evident in the respiratory system. The increased risk of illness in the respiratory system in children does not seem to be caused primarily by air pollutants, but rather, as the results for neighbourhood noise demonstrate, by emotional stress.

TP53 and P21 polymorphisms: response to cisplatinum/paclitaxel-based chemotherapy in ovarian cancer

Ovarian cancer (OC) is the most lethal gynaecologic cancer and its standard treatment consists of platinum-based chemotherapy after cytoreductive surgery. The p53 protein plays a critical role on different cellular processes in response to DNA damage and it is responsible for transcriptional induction of the P21 gene. We have analysed 114 blood samples in order to investigate the effect of the TP53 codon 72 and the P21 3'UTR polymorphisms in response to cisplatinum/paclitaxel chemotherapy for OC treatment. The genotypes of the TP53 codon 72 and P21 3'UTR polymorphism were identified using AS-PCR and PCR-RFLP, respectively. Our results indicate that the TP53 P allele is associated with a worse prognosis (P=0.011) while P21 polymorphism genotypes did not reveal any statistically significant result (P>0.05). Furthermore, simultaneous carriers of the TP53 AA genotype and the P21 CC genotype demonstrate a longer progression-free interval (P=0.020). This study suggests that the characterisation of a genetic profile can contribute to the definition of a better chemotherapy treatment.

Modulation of endocytosis in pollen tube growth by phosphoinositides and phospholipids

In plants, tip-growing cells represent an ideal system to investigate signal transduction mechanisms, and among those, pollen tubes are one of the favourite models. Many signalling pathways have been identified during germination and tip growth, namely, Ca2+, calmodulin, phosphoinositides, cyclic AMP, and GTPases. Not surprisingly, the apical secretory machinery, essential for tip growth, seems to be an intersection point for all these pathways. Recently, the phospholipid phosphatidic acid was also suggested to actively participate in the control of endo- and exocytosis and to interfere with the correct positioning of the actin cytoskeleton. Phosphatidic acid seems to act concertedly with the phosphoinositides phosphatidylinositol 4,5-bisphosphate and D-myo-inositol 1,4,5-trisphosphate. Here we review previous data and discuss additional evidence that these three molecules have a combined action modulating both the actin cytoskeleton and the apical secretory machinery. We further discuss how these findings can be integrated into a working model for pollen tube apical secretion that contemplates the existence of a rapid endocytosis mechanism.

Desulfurization of dibenzothiophene, benzothiophene, and other thiophene analogs by a newly isolated bacterium, Gordonia alkanivorans strain 1B

A novel bacterium, Gordonia alkanivorans strain 1B, was isolated from hydrocarbon-contaminated soil. Assessment of the biodegradation of distinct organic sulfur-compounds, such as dibenzothiophene (DBT), benzothiophene (BT), DBT sulfone, and alkylated tiophenic compounds, as the sole source of sulfur was investigated. G. alkanivorans strain 1B was able to remove selectively the sulfur from DBT while keeping intact the remaining carbon-carbon structure. Orthophenyl phenol (2-hydroxybiphenyl) was the only detected metabolic product. The bacterial desulfurization activity was repressed by sulfate. G. alkanivorans strain 1B consumed 310 microM DBT after 120 h of cultivation, corresponding to a specific desulfurization rate of 1.03 micromol/(g of dry cells x h). When an equimolar mixture of DBT/BT was used as a source of sulfur in the growth medium, G. alkanivorans strain 1B assimilated both compounds in a sequential manner, with BT as the preferred source of sulfur. Only when BT concentration was decreased to a very low level was DBT utilized as the source of sulfur for bacterial growth. The specific desulfurization overall rates of BT and DBT obtained were 0.954 and 0.813 micromol/(g of dry cells x h), respectively. The newly isolated G. alkanivorans strain 1B has good potential for application in the biodesulfurization of fossil fuels.

IMRT for breast. A planning study

BACKGROUND AND PURPOSE

To evaluate the performance of ten different treatment-planning systems when intensity modulated (IMRT) plans are designed for breast treatments that include the irradiation of the internal mammary chain.

PATIENTS AND METHODS

A dataset of five patients (CT images and volumes of interest) was distributed to design IMRT plans on the ten systems. To minimise biases, the same geometry and clinical planning aims were imposed on the individual plans. Results were analysed in terms of dose distributions and dose volume histograms.

RESULTS AND CONCLUSIONS

For target coverage, the volume receiving more than 95% of the prescribed dose ranged from 77% (OTP) to 91% (Eclipse and Pinnacle), the volume receiving more than 107% ranged from 3.3% (Hyperion) to 23.2% (OTP). The mean dose to ipsilateral lung ranged from 13 Gy (Eclipse) to 18 Gy (OTP). The volume of the contralateral breast receiving more than 10 Gy ranged from 3% (Pinnacle) to 26% (Precise). The volume of heart receiving more than 20 Gy ranged from 7% (Eclipse) to 47% (Precise), the maximum significant dose to heart ranged from approximately 27 Gy (XiO) to approximately 49 Gy (Precise). The maximum significant dose to healthy tissue ranged from approximately 51 Gy (Eclipse) to approximately 62 Gy (OTP). It was also possible to show that the treatment geometry proposed here enables to minimise contralateral breast irradiation while keeping minimal ipsilateral lung (or heart) involvement and satisfactory target coverage.

The Population and Reproductive Health Programme in Brazil 1990-2002: Lessons Learned

The story of Brazil's evolution in sexual and reproductive health and rights during the 1990s documents not only a decade of change in the population field, but the powerful role of social movements in a democracy. Between October and December 2002, 23 people were interviewed about where they believe progress has been made in Brazil and where there are still needs in relation to population trends, sexual and reproductive rights, and health policies. This paper contains excerpts from the full report and covers the economic and political background of Brazil; the role of non-governmental and women's organisations in influencing the national agenda; the intersection of national and international agendas on population and development, HIV/AIDS, human rights, racism and other issues; changes in sexual and reproductive health policies; HIV/AIDS policy progress, perhaps most importantly mandatory free treatment for people with HIV/AIDS; recent progress in women's health, especially in relation to antenatal and obstetric services, and services addressing violence against women. Finally it describes the role of policy accountability mechanisms that aim to ensure that the many excellent policies that have been passed since 1990 are implemented in a decentralised health system of national, state and local management and services.

Detection of -lactamases in nosocomial gram negative clinical isolates

-lactamases represent the most common mechanism of -lactam resistance. Extended spectrum -lactamases (ESBLs) represent a major group of -lactamases currently being identified worldwide in large numbers along with inducible AmpC -lactamases and derepressed mutants. The present study was done to detect -lactamase production in clinical isolates by rearranging routine discs used in reporting susceptibility to specifically assess ESBLs, AmpC -lactamases (both inducible and hyperproducers i.e., derepressed mutants). A total of 286 clinical isolates were studied using a novel predictor disc approximation method to detect the above mechanisms of resistance with careful use and placement of antimicrobial discs. Of the 286 isolates, 151(53%) were ESBL producers of which 131(46%) were also derepressed mutants while remaining 20(7%) were plain ESBL producers. Forty (14%) were plain derepressed mutants. Inducible AmpC -lactamase production was detected in 19(7%) of the isolates. The commonest ESBL producers were E.coli and K. pneumoniae. The high incidence of -lactamase production due to multiple mechanisms in clinical isolates is alarming and urgent action needs to be taken from both a therapeutic and infection control perspective.

Comparison of pyrazinamide drug susceptibility of M. tuberculosis by radiometric BACTEC and enzymatic pyrazinamidase assay

The aim of this study was to perform pyrazinamide (PZA) susceptibility testing of M. tuberculosis by enzymatic PZA assay and compare the results with radiometric BACTEC 460 TB system and LJ proportion method. One hundred and thirty clinical isolates of M. tuberculosis were included in the study. Of the 130 clinical isolates tested, five were resistant and 124 were sensitive by both methods thus giving overall sensitivity and specificity of 83.33% and 100% respectively. Concordance was found in 129 out of 130 strains tested by all three methods. Pyrazinamidase assay can be used as an alternative to BACTEC and LJ proportion method.

Postoperative wound infection in patients undergoing coronary artery bypass graft surgery: a prospective study with evaluation of risk factors

PURPOSE

Wound infection is an important cause of morbidity and occasional mortality after coronary artery bypass graft surgery (CABG). The aim of this study was to report postoperative wound infection in CABG surgery patients.

METHODS

Consecutive patients undergoing CABG surgery between January 1998 and October 1999 have been studied. The exclusion criteria included, age less than 30 years, penicillin / cephalosporin allergy and associated other cardiac pathologies. The parameters studied were age, sex, obesity, hypertension, diabetes, myocardial infarction, chronic renal failure, previous surgeries, alcohol consumption, smoking, length of pre and postoperative hospital stay, antibiotic prophylaxis, MRSA screening, and duration of surgery. Wounds were classified as per modified CDC's NNIS criteria. Suspected sites of infection were cultured and antibiotic susceptibility of cultured organisms was tested. Postoperative follow up was for two months.

RESULTS

Six hundred and fifteen patients were studied. Of these 116 (18.86%) developed SSI, involving sternum 75%, leg 21.3%, and forearm sites 3.44%. Organisms isolated at sternum site were MSSE, MRSA, and MRSE, at leg site E. coli and MSSE, and at forearm site MSSE and MSSA. Sternal site, obesity, diabetes mellitus and female sex were associated with significantly higher infection rates (p= 0.001). No antibiotic protocol proved more effective. SSI increased the postoperative hospital stay and the total treatment cost.

CONCLUSIONS

Post CABG surgery SSI rate is high. Sternum and leg are the common infection sites. Obesity, uncontrolled diabetes mellitus and female sex are associated with higher infection rates. "Higher" antibiotics do not lower postoperative infection rates.

High capacity xylose transport in Candida intermedia PYCC 4715

Xylose-utilising yeasts were screened to identify strains with high xylose transport capacity. Among the fastest-growing strains in xylose medium, Candida intermedia PYCC 4715 showed the highest xylose transport capacity. Maximal specific growth rate was the same in glucose and xylose media (mu(max)=0.5 h-1, 30 degrees C). Xylose transport showed biphasic kinetics when cells were grown in either xylose- or glucose-limited culture. The high-affinity xylose/proton symport system (Km = 0.2 mM, Vmax = 7.5 mmol h-1 g-1) was more repressed by glucose than by xylose. The less specific low-affinity transport system (K = 50 mM, Vmax = 11 mmol h-1 g-1) appeared to operate through a facilitated-diffusion mechanism and was expressed constitutively. Inhibition experiments showed that glucose is a substrate of both xylose transport systems.

Rapid detection of rifampicin resistance in M. tuberculosis by phage assay

Increase in multidrug-resistant M. tuberculosis (MDR-TB) has become a great cause of concern and rifampicin resistance is considered to be a good predictor of MDR-TB in many parts of the world. Its rapid detection will allow alteration in treatment regimens in time to reduce the spread of the disease. Detection of rifampicin resistance by phage assay is a useful tool as mycobacteriophages are specific for M. tuberculosis complex and detect viable cells only. In our study, we analyzed 85 samples for rifampicin resistance using a novel mycobacteriophage based test (Phage assay) and radiometric BACTEC 460 TB. Of the 85 samples, 70 (82.35%) were resistant and 12 (14.10%) were sensitive by both methods. Our study yielded a sensitivity and specificity of 100% and 80% respectively. A good correlation was observed with conventional LJ proportion method. We conclude that phage assay allows determination of rifampicin resistance within 48 hours from culture, reducing the time taken to define susceptibility results by BACTEC 460 TB and LJ proportion method (5-7 days and 6-8 weeks respectively).

Evaluation of a new phage amplification technology for rapid diagnosis of tuberculosis

PURPOSE

Rapid diagnosis of tuberculosis is essential to initiate timely and appropriate treatment to curb the spread of this potentially life threatening disease. The purpose of this study was to evaluate a phage amplification technology viz., FASTPlaque TB, for the diagnosis of tuberculosis.

METHODS

We evaluated the clinical utility of this new assay by analyzing 50 respiratory and 40 non-respiratory specimens, using FASTPlaque TB kit (Biotec Laboratories, UK) and the performance was compared with TB Bactec 460 semi-automated liquid culture system and conventional LJ culture method.

RESULTS

In case of respiratory specimens phage assay gave good specificity (100%) compared with TB Bactec whereas with respect to LJ method the sensitivity and specificity were 93.1% and 88.2% respectively. In case of non-respiratory specimens comparison of results obtained by phage assay showed sensitivity of 90.9% and specificity of 88.8% with respect to TB Bactec and 87.5% and 93.8% with respect to LJ method.

CONCLUSIONS

We believe that this new low cost assay may have widespread applicability, especially in developing countries, due to its manual format and rapid reporting of results.

Effects of posttraining treatments in the posterior cingulate cortex on short- and long-term memory for inhibitory avoidance in rats

Adult male Wistar rats were bilaterally implanted with indwelling cannulae in the caudal region of the posterior cingulate cortex. After recovery, animals were trained in a step-down inhibitory avoidance task (3.0-s, 0.4-mA foot shock) and received, right after training, a 0.5-microl infusion of vehicle (phosphate-buffered saline, pH 7.4), of the GABA(A) receptor agonist muscimol (0.1 or 0.5 microg), of the cAMP-dependent protein kinase (PKA) stimulant Sp-cAMPS (0.1 or 0.5 microg), or of the PKA inhibitor Rp-cAMPS (0.1 or 0.5 microg). Animals were tested twice, 1.5 h and, again, 24 h after training, in order to examine the effects of these agents on short- and long-term memory, respectively. Muscimol (0.5 but not 0.1 microg) hindered retention for both short- and long-term memory (p <.05). Rp-cAMPS (0.1 or 0.5 microg) hindered retention for short-term memory (p <.05). In addition, these animals showed lower, but not significantly lower, latencies than controls in the test session for long-term memory (p >.10). A trend toward an amnesic effect on long-term memory was also observed after Sp-cAMPS infusion at 0.1 microg (p <.10). These results show that strong stimulation of GABAergic synapses in the caudal region of the rat posterior cingulate cortex right after training impairs short- and long-term memory (the latter less dramatically). The same occurs by inhibiting PKA activity with regard to STM and possibly to LTM.

Derivative spectrophotometry as a tool for the determination of drug partition coefficients in water/dimyristoyl-L-alpha-phosphatidylglycerol (DMPG) liposomes

The partition coefficients (K(p)) between lipid bilayers of dimyristoyl-L-alpha-phosphatidylglycerol (DMPG) unilamellar liposomes and water were determined using derivative spectrophotometry for chlordiazepoxide (benzodiazepine), isoniazid and rifampicin (tuberculostatic drugs) and dibucaine (local anaesthetic). A comparison of the K(p) values in water/DMPG with those in water/DMPC (dimyristoyl-L-alpha-phosphatidylcholine) revealed that for chlordiazepoxide and isoniazid, neutral drugs at physiological pH, the partition coefficients are similar in anionic (DMPG) and zwitterionic (DMPC) liposomes. However, for ionised drugs at physiological pH, the electrostatic interactions are different with DMPG and DMPC, with the cationic dibucaine having a stronger interaction with DMPG, and the anionic rifampicin having a much larger K(p) in zwitterionic DMPC. These results show that liposomes are a better model membrane than an isotropic two-phase solvent system, such as water-octanol, to predict drug-membrane partition coefficients, as they mimic better the hydrophobic part and the outer polar charged surface of the phospholipids of natural membranes.

29Si NMR and hidden order in URu2Si2

Below T(N) approximately 17 K the 29Si NMR line in URu2Si2 exhibits a previously unobserved field-independent nearly isotropic contribution to the linewidth, which increases to approximately 12 G as T-->0. We argue that this feature does not arise from static freezing of the U-spin magnetization, but is due to coupling between 29Si spins and a hidden order parameter. We discuss time-reversal symmetry-breaking orbital antiferromagnetism and indirect nuclear spin-spin interactions as possible coupling mechanisms. Further NMR experiments and theoretical calculations are suggested.

[Dysgenetic male pseudohermaphroditism]

Dysgenetic male pseudohermaphroditism is the result of a defect of testis development that encompasses a large clinical heterogeneity. It is characterized by bilateral dysgenetic testis, absence of mullerian regression, ambiguous genitalia and/or stigmata of Turner's syndrome in the majority of the cases. Typically, these individuals have either a 46,XY or 45,X/46,XY karyotype. The authors present four cases of dysgenetic male psudohermaphroditism, with ages of diagnosis between 1 month and 17 years old. The first had a male phenotype with stigmata of Turner's syndrome and the others ambiguous genitalia. Two patients were 45,X/46,XY and 45X/47,XYY mosaics and the other two were 46,XY. Gonadal karyotyping showed mosaicism (45,X/46,XY) in all four cases. In the first case was programed orquidectomy; all the others assigned a male gender, with regular follow-up until the puberty.

Involvement of the serotonergic type 1A (5-HT1A) receptor in the agranular insular cortex in the consolidation of memory for inhibitory avoidance in rats

Adult male Wistar rats were bilaterally implanted with indwelling cannulae in the agranular insular cortex of the prefrontal cortex. After recovery, animals were trained in a step-down inhibitory avoidance task (3.0-s, 0.4-mA footshock) and received, immediately after training, a 0.5-microl infusion of the serotonergic type 1A (5-HT1A) receptor agonist dipropylamino-8-hydroxy-1,2,3,4-tetrahydronaphthalene hydrobromide (8-OH-DPAT) or of the 5- HT1A receptor antagonist 1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl] piperazine hydrobromide (NAN-190), or of vehicle alone (20% DMSO). Retention testing was carried out 24 h after training. 8-OH-DPAT (1.25 and 6.25 microg but not 0.0125 or 0.125 microg) was amnesic. NAN-190 was not effective at 0.125 or 1.25 microg any dose but reversed amnesia when given at 1.250 microg simultaneously with both effective doses of 8-OH-DPAT. These results show that an overactivation of 5-HT1A receptors in the agranular insular cortex impairs memory consolidation of inhibitory avoidance, in rats, immediately after training. This suggests that these receptors of the insular cortex may modulate memory consolidation.

Performance improvement in pain management for home care and hospice programs

This performance improvement project was undertaken to determine staff competency in pain management in several home care and hospice programs. The process used involved identifying and establishing the project, diagnosing the cause, remedying the cause, and holding the gains. Once the problem was identified and confirmed, the group worked to improve the competency of staff.

Significance of HBV DNA by PCR over serological markers of HBV in acute and chronic patients

A study was undertaken to determine Hepatitis B virus DNA (HBV DNA) by PCR in acute and chronic hepatitis B infection and to correlate it with serological markers. Three hundred and forty-five serum samples of patients from all over India were categorized into different groups according to their serological profile. HBV DNA was detected upon amplification in 166/263 patients in group A, 3/14 patients in group B, and 2/32 patients in group C, and was not detected in groups D and E. The presence of HBV DNA in 49 patients with non-replicative HBV disease, as defined by the absence of HBeAg, suggests low levels of viremia which is also supported by the abnormal liver function tests (LFTs) in these patients. In addition, HBV DNA was detected in small proportion of individuals with past HBV infection. This data suggests that, detection of HBV DNA by amplification technique serves as an important supplementary tool besides serology in a number of clinical settings, especially in determining low levels of viremia in patients with non-replicative HBV disease and chronic hepatitis, and also in a few patients with past HBV infection and who could be asymptomatic carriers of HBV infection.

Novelty enhances retrieval: molecular mechanisms involved in rat hippocampus

Rats exposed to a novel environment just prior to or 1-2 h, but not 4 or 6 h, before retention testing exhibited an enhanced retrieval of a one-trial inhibitory avoidance training. The bilateral intrahippocampal infusion of PD098059, an inhibitor of mitogen-activated protein kinase (MAPK), the specific upstream activator of p42 and p44 MAPKs, given 10 min before the exposure to the novel environment, blocked the enhancing effect of novelty on memory retrieval. In addition, prenovelty infusion of DL-2-amino-5-phosphonovalerate (APV), an antagonist of glutamate NMDA receptors, produced similar effects. The exposure to the novel environment is associated with an activation of p42 and p44 MAPKs and an increase in the phosphorylation state of the transcription factor cAMP response element binding protein (CREB). No changes were observed in cAMP-dependent protein kinase (PKA) activity or in alpha-CAMKII activation. Taken together, our results indicate that novelty activates hippocampal MAPKs, which are necessary, along with glutamate NMDA receptors, for the enhancing effect of novelty on retrieval.

[Saphenous vein graft bypass from the external carotid artery to the supraclinoid internal carotid artery to treat a giant aneurysm of the cavernous internal carotid: case report]

Alternative surgical procedures to treat unclippable aneurysms of the intracavernous carotid artery include proximal vessel occlusion and trapping. Those techniques, even in patients with rich collateral vessels, are associated with risk of hemodynamic compromise and ischemic complications. Therefore, a safe treatment requires revascularization to maintain blood flow to the involved territories. We report the case of a 47-year-old female, with ischemic signs and symptoms and a right third nerve palsy caused by a giant aneurysm, partially trombosed, of the intracavernous carotid artery. The patient was submitted to trapping after a saphenous vein graft bypass from the external carotid artery to the supraclinoid internal carotid artery. The surgical result was good without complications.

Two-dimensional fluorometry coupled with artificial neural networks: a novel method for on-line monitoring of complex biological processes

The use of two-dimensional scanning fluorometry as an on-line, noninvasive, in situ bioreactor monitoring technique is extended to complex bioprocesses using mixed cultures, with particular attention to biofilm systems. Using the example of spectra subtraction, it is demonstrated that established methods for fluorescence data analysis have a limited capability of utilizing overall fluorometric information. Artificial neural networks (ANNs) are introduced as a novel nonlinear and nonmechanistic technique for interpreting the highly complex fluorescence maps. It is shown that ANNs are able to infer process performance parameters in a pattern recognition approach, based on the entire fluorescence "fingerprint" of the biological system. The studies were carried out using an extractive membrane bioreactor (EMB) for the degradation of chlorinated organic compounds, operating with mixed cultures. Model pollutants em- ployed were 1,2-dichloroethane, 3-chloro-4-methylaniline, and p-toluidine.

Pharmacological differences between memory consolidation of habituation to an open field and inhibitory avoidance learning

Rats implanted bilaterally with cannulae in the CA1 region of the dorsal hippocampus or the entorhinal cortex were submitted to either a one-trial inhibitory avoidance task, or to 5 min of habituation to an open field. Immediately after training, they received intrahippocampal or intraentorhinal 0.5-microl infusions of saline, of a vehicle (2% dimethylsulfoxide in saline), of the glutamatergic N-methyl-D-aspartate (NMDA) receptor antagonist 2-amino-5-phosphono pentanoic acid (AP5), of the protein kinase A inhibitor Rp-cAMPs (0.5 microg/side), of the calcium-calmodulin protein kinase II inhibitor KN-62, of the dopaminergic D1 antagonist SCH23390, or of the mitogen-activated protein kinase kinase inhibitor PD098059. Animals were tested in each task 24 h after training. Intrahippocampal KN-62 was amnestic for habituation; none of the other treatments had any effect on the retention of this task. In contrast, all of them strongly affected memory of the avoidance task. Intrahippocampal Rp-cAMPs, KN-62 and AP5, and intraentorhinal Rp-cAMPs, KN-62, PD098059 and SCH23390 caused retrograde amnesia. In view of the known actions of the treatments used, the present findings point to important biochemical differences in memory consolidation processes of the two tasks.

Enumeration of T cells specific for RD1-encoded antigens suggests a high prevalence of latent Mycobacterium tuberculosis infection in healthy urban Indians

Knowledge of the prevalence of latent Mycobacterium tuberculosis infection is crucial for effective tuberculosis control, but tuberculin skin test surveys have major limitations, including poor specificity because of the broad antigenic cross-reactivity of tuberculin. The M. tuberculosis RD1 genomic segment encodes proteins, such as early secretory antigenic target (ESAT)-6, that are absent from M. bovis bacille Calmette-Guérin (BCG) and most environmental mycobacteria. We recently identified circulating ESAT-6-specific T cells as an accurate marker of M. tuberculosis infection. Here, interferon-gamma-secreting T cells specific for peptides derived from ESAT-6 and a second RD1 gene product, CFP10, were enumerated in 100 prospectively recruited healthy adults in Bombay (Mumbai), India. Eighty percent responded to >/=1 antigen, and many donors had high frequencies of T cells that were specific for certain immunodominant peptides. In contrast, of 40 mostly BCG-vaccinated, United Kingdom-resident healthy adults, none responded to either antigen. This study suggests an 80% prevalence of latent M. tuberculosis infection in urban India.

Determination of metals in plant samples by using a sector field inductively coupled plasma mass spectrometer

The capability of pine needles to be used as bioindicators of trace metals in the environment is discussed. Samples were collected around the Instituto de Pesquisas Energéticas e Nucleares, the largest nuclear research center in South America and chosen to be the sampling target area. Results obtained for the elemental content of Th and U in samples collected nearby an uranium facility were, respectively, 0.072 and 0.042 mg kg(-1), while the results obtained for the La, Ce and Sm content in a sample collected in the vicinity of an extraction laboratory were, respectively, 0.22, 0.88 and 0.39 mg kg(-1). All these values are higher than the ones obtained with a reference sample (La 0.12; Ce 0.19, Th 0.020 and U 0.012 mg kg(-1)), located far from the target area. Internal standardization was used to compensate the non-spectral interference of the different elements present in the sample solution matrix. The chemical elements bismuth (Bi) and indium (In) were chosen as internal standards. In order to control the accuracy of the chemical measurement process, certified samples of pine needles (NBS SRM 1575) were also analyzed. The results obtained show the capability of the investigated method in the determination of the relevant trace metals in the environment.

Fiber-rich diets alter rat intestinal leukocytes metabolism

This study addressed the following question: What is the effect of fermentable and nonfermentable fiber-rich diets on intestinal immune cells' function and metabolism? For this purpose, weaning rats received, for 8 weeks, two types of fiber-enriched (30%) diets with different fermentable/nonfermentable fiber ratios, that is, oat bran (0.3) and wheat bran (0.14). The results of these two experimental groups were compared with those of the low-fiber control group having a 0.22 fermentable/nonfermentable fiber ratio. The total number and proportion of leukocytes in plasma, total number of cells in the lymphoid organs, lymphocyte proliferative activity and capacity of phagocytosis, hydrogen peroxide production, and adherence of macrophages were investigated. The activities of key enzymes of glycolysis and glutaminolysis, and of the Krebs cycle of lymphocytes from the mesenteric lymph nodes and macrophages from the intraperitoneal cavity were determined. The metabolic response of lymphocytes and macrophages from rats fed the three diets to Bacillus Calmette-Guérin-stimulus was also investigated. The number of lymphocytes in the mesenteric lymph nodes was lower in both fiber-rich diets than in the control but did not have any difference in the remaining lymphoid organs. Wheat bran caused a significant reduction in the phagocytosis capacity and adherence index of macrophages, whereas oat bran did not have a significant effect. The response of glucose and glutamine metabolism to Bacillus Calmette-Guérin-stimulus was not altered by the diets in lymphocytes, whereas in macrophages, the increase in glutaminase and hexokinase activities was abolished.

Involvement of the medial precentral prefrontal cortex in memory consolidation for inhibitory avoidance learning in rats

Adult male Wistar rats were trained in a step-down inhibitory avoidance learning task (3.0-s, 0.4-mA foot shock), received a 0.5-microl infusion of muscimol (0.02, 0.1, or 0.5 microg), AP5 (0.16, 0.34, 0. 5, 1.6, or 5.0 microg), SCH 23390 (0.05, 0.34, 0.5, or 1.75 microg), saline, or vehicle (DMSO 20%) into the anterior medial precentral area (Fr2) (CI) immediately after training, and were tested 24 h later. Muscimol (0.02, 0.1, or 0.5 microg), AP5 (0.34 or 0.5 microg), or SCH (0.5 or 1.75 microg) were amnesic. Then, animals were infused with muscimol (0.1 or 0.5 microg), AP5 (0.34, 0.5, or 5.0 microg), or SCH (0.5 microg) at other posttraining times and/or into the junction of Fr1-Fr2 (CII). Muscimol (0.1 and 0.5 microg) or SCH into CI were amnesic when given 90 or 180 min after training, but not when given 270 min after training. Muscimol (0.5 microg, but not 0.1 microg) or SCH into CII were amnesic when given 90 min after training, but not when given 0 or 180 min after training. AP5 (0.5, but not 5.0 microg) was amnesic when given into CI, but not into CII, at 0 or 180 min posttraining, and a trend toward an amnesic effect was seen at 90 min posttraining. The results suggest that 1) the glutamatergic, GABAergic, and dopaminergic systems in Fr2 are involved in the consolidation of memory for inhibitory avoidance learning, either directly or as parts of modulatory systems; and 2) timing of involvement of anterior Fr2 (CI) is different from that of posterior Fr2 (CII).

NMDA receptor antagonism in the basolateral amygdala blocks enhancement of inhibitory avoidance learning in previously trained rats

Extensive evidence suggests that N-methyl-D-aspartate (NMDA) glutamate receptor channels in the amygdala are involved in fear-motivated learning, and infusion of NMDA receptor antagonists into the amygdala blocks memory of fear-motivated tasks. Recent studies have shown that previous training can prevent the amnestic effects of NMDA receptor antagonists on spatial learning. In the present study, we evaluated whether infusion of the NMDA antagonist D,L-2-amino-5-phosphonopentanoic acid (AP5) into the basolateral nucleus of the amygdala (BLA) impairs reinforcement of inhibitory avoidance learning in rats given previous training. Adult male Wistar rats (220-310 g) were bilaterally implanted under thionembutal anesthesia (30 mg/kg, i.p.) with 9.0-mm guide cannulae aimed 1.0 mm above the BLA. Infusion of AP5 (5.0 microg) 10 min prior to training in a step-down inhibitory avoidance task (0.4 mA footshock) blocked retention measured 24 h after training. When infused 10 min prior to a second training session in animals given previous training (0.2 mA footshock), AP5 blocked the enhancement of retention induced by the second training. Control experiments showed that the effects were not due to alterations in motor activity or footshock sensitivity. The results suggest that NMDA receptors in the basolateral amygdala are involved in both formation of memory for inhibitory avoidance and enhancement of retention in rats given previous training.

Different hippocampal molecular requirements for short- and long-term retrieval of one-trial avoidance learning

Rats were trained in one-trial step-down inhibitory avoidance and tested either 3 h or 31 days later. Ten minutes prior to the retention test, through indwelling cannulae placed in the CA1 region of the dorsal hippocampus, they received 0.5 microl infusions of: saline, a vehicle (2% dimethylsulfoxide in saline), the glutamate NMDA receptor blocker, aminophosphonopentanoic acid (AP5) (5.0 microg), the AMPA/kainate receptor blocker, cyanonitroquinoxaline dione (CNQX) (0.25 or 1.25 microg), the metabotropic receptor antagonist, methylcarboxyphenylglycine (MCPG) (0.5 or 2.5 microg), the inhibitor of calcium/calmodulin-dependent protein kinase II (KN62) (3.5 microg), the inhibitor of cAMP-dependent protein kinase (PKA), Rp-cAMPs (0.1 or 0.5 microg), the stimulant of the same enzyme, Sp-cAMPs (0.1 or 0.5 microg), or the inhibitor of the mitogen-activated protein kinase (MAPK) kinase, PD098059 (10 or 50 microM). CNQX, KN62 and PD098059 were dissolved in the vehicle; the other drugs were dissolved in saline. All these drugs, at the same doses, had been previously found to affect short- and long-term memory formation of this task. Retrieval measured 3 h after training (short-term memory) was blocked by CNQX and MCPG, and was unaffected by all the other drugs. In contrast, retrieval measured at 31 days was blocked by MCPG, Rp-cAMPs and PD098059, enhanced by Sp-cAMPs, and unaffected by CNQX, AP5 or KN62. The results indicate that, in CA1, glutamate metabotropic receptors are necessary for the retrieval of both short- and long-term memory; AMPA/kainate receptors are necessary for short-term but not long-term memory retrieval, and NMDA receptors are uninvolved in retrieval. Both the PKA and MAPK signalling pathways are required for the retrieval of long-term but not short-term memory.

Pharmacological demonstration of the differential involvement of protein kinase C isoforms in short- and long-term memory formation and retrieval of one-trial avoidance in rats

RATIONALE

The hippocampal protein kinase C (PKC) family is involved in the early events of consolidation of long-term potentiation (LTP) and long-term memory (LTM). Results so far are indecisive about which PKC isoform is involved and as to whether any of them plays a role in short-term memory (STM) processes, which have recently been shown to be separate from those of LTM in the hippocampus-dependent one-trial step-down inhibitory avoidance task.

OBJECTIVES

To measure the effect of two PKC inhibitors, one (Gö 6976) selective to the calcium-dependent isoforms alpha and beta I, and the other (Gö 7874) unspecific as to PKC isoforms on the formation and retrieval of STM and LTM of one-trial inhibitory avoidance.

METHODS

Rats bilaterally implanted with cannulae in the CA1 region of the dorsal hippocampus were trained in one-trial step-down inhibitory avoidance. The effect of these two drugs on STM and LTM formation was investigated as follows. Animals were infused 10 min before or 50, 110, or 170 min after inhibitory avoidance training with a vehicle (2% dimethylsulfoxide in saline), or with Gö 6976 (0.92 nM or 4.6 nM) or Gö 7874 (1.96 nM or 8 nM) dissolved in the vehicle. Infusion volume was 0.5 microliter in all cases. Animals were tested 1.5 h and 3 h after training for STM and at 24 h for LTM. In order to study the effects of these compounds on retrieval, they were infused into the hippocampus 10 min prior to STM testing at 3 h (see above) or 10 min before LTM testing at 24 h. In addition, the effect of Gö 6976 and Gö 7874 was studied on general activity measured in an open field, and on performance in an elevated plus maze.

RESULTS

STM was suppressed by 4.6 nM Gö 6976 given 10 min before or 50 min after training. LTM was cancelled by the higher dose of the two compounds given 10 min before, or 50 min or 110 min after training. None of the two compounds infused 170 min post-training affected the retrieval of STM measured 10 min later. However, both compounds given 10 min before testing inhibited the retrieval of LTM measured at 24 h. This effect cannot be attributed to influences on locomotor activity or anxiety levels, since the drugs had no effect on performance in the open field but were mildly "anxiogenic" (pro-conflict) and reduced the number of entries into open and closed arms and rearings.

CONCLUSIONS

LTM consolidation requires in part alpha- and/or beta 1-PKC and in part other PKC isoforms. STM formation requires instead only alpha and/or beta I-PKC and during a more limited period of time. In addition, PKC appears not to be necessary for the retrieval of STM, but is crucial for the retrieval of LTM. These findings further point to a biochemical separation of STM and LTM, as ascertained in numerous previous studies.

Differential role of hippocampal cAMP-dependent protein kinase in short- and long-term memory

One-trial step-down inhibitory (passive) avoidance training is followed by two peaks of cAMP-dependent protein kinase (PKA) activity in rat CA1: one immediately after training and the other 3 h later. The second peak relies on the first: Immediate posttraining infusion into CA1 of the inhibitor of the regulatory subunit of PKA, Rp-cAMPS, at a dose that reduces PKA activity during less than 90 min, cancelled both peaks. Long-term memory (LTM) of this task measured at 24 h depends on the two peaks: Rp-cAMPS given into CA1 0 or 175 min posttraining, but not between those times, blocked LTM. However, the effect of immediate posttraining Rp-cAMPS on LTM could not be reversed by the activator of the regulatory subunit of PKA, Sp-cAMPS, given at 180 min, which suggests that, for LTM, the first peak may be more important than the second. When given at 0, 22, 45, or 90, but not at 175 min from training, Rp-cAMPS blocked short-term memory (STM) measured at 90 or 180 min. This effect of immediate posttraining Rp-cAMPS infusion on STM but not that on LTM was readily reversed by Sp-cAMPS infused 22 min later. On its own, Sp-cAMPS had effects exactly opposite to those of the inhibitor. It enhanced LTM when given at 0 or 175 min from training, and it enhanced STM when given at 0, 22, 45, or 90 min from training. These findings show that STM and LTM formation require separate PKA-dependent processes in CA1. STM relies on the continued activity of the enzyme during the first 90 min. LTM relies on the two peaks of PKA activity that occur immediately and 180 min posttraining.