Nutritional status and functional status of the pancreatic cancer patients and the impact of adjacent symptoms

RATIONALE & AIMS

Pancreatic cancer (PC) is the third most common type of gastrointestinal tract cancer in Europe and the fourth leading cause of death by cancer. Its initial stage is asymptomatic Therefore, the diagnosis tends to be late leading to locally advanced stages that presuppose late and debilitating symptoms, which consequently makes the Nutritional Status (NS) get worse. The weight loss (WL), malnutrition, and oncologic cachexia, which are quite prevalent in PC patients, reflect a poor prognosis. We aimed to track and evaluate the NS and Functional Status (FS) of PC patients (hospitalized patients - HP and Day Hospital patients - DHP) and associate NS with symptoms with nutritional impact and FS.

METHODS

Observational cohort study in PC patients from Garcia de Orta Hospital. NS was tracked and evaluated using Nutritional Risk Screening (NRS-2002) and Patient-Generated Subjective Global Assessment (PG-SGA). To assess FS we used the Eastern Cooperative Oncology Group (ECOG), Karnofsky Performance Scale Index (KPSI) and Handgrip Dynamometer (HGD).

RESULTS

41 PC patients (30-HP and 11-DHP). 29 patients in stage IV of the tumor. 24 with a WL >10% in the last 6 months. 37 manifest symptoms with nutritional impact. 30 to 34 malnourished according to the GLIM criteria and PG-SGA, respectively. 11 in ECOG level 2 and corresponding KPSI, 10 in level 3 and 8 in level 4. 28 patients had a value of HGD below the 10th percentile. NRS-2002, PG-SGA and GLIM criteria were positively correlated with the symptoms (p < 0.01), % WL (p < 0.01) and ECOG (p < 0.01) and negatively correlated with HGS (p < 0.05 - NRS-2002; p < 0.01 - PG-SGA and GLIM criteria).

CONCLUSIONS

PC patients manifest debilitating symptoms with nutritional impact, namely severe WL and anorexia, which in turn lead to deterioration of the NS and FS. It is an oncology population with high nutritional risk and a higher prevalence of malnutrition, associated with severe % WL and symptoms and a sharp decline in FS.

Status of COMPASS RICH-1 Upgrade with MPGD-based Photon Detectors

A Set of new MPGD-based Photon Detectors is being built for the upgrade of COMPASS RICH-1. The detectors cover a total active area of 1.4 m2 and are based on a hybrid architecture consisting of two THGEM layers and a Micromegas. A CsI film on one THGEM acts as a reflective photocathode. The characteristics of the detector, the production of the components and their validation tests are described in detail.

Education and severe maternal outcomes in developing countries: a multicountry cross-sectional survey

OBJECTIVE

To assess the relationship between education and severe maternal outcomes among women delivering in healthcare facilities.

DESIGN

Cross-sectional study.

SETTING

Twenty-nine countries in Africa, Asia, Latin America, and the Middle East.

POPULATION

Pregnant women admitted to 359 facilities during a period of 2-4 months of data collection between 2010 and 2011.

METHODS

Data were obtained from hospital records. Stratification was based on the Human Development Index (HDI) values of the participating countries. Multivariable logistic regression analyses were conducted to assess the association between maternal morbidity and education, categorised in quartiles based on the years of formal education by country. Coverage of key interventions was assessed.

MAIN OUTCOME MEASURES

Severe maternal outcomes (near misses and death).

RESULTS

A significant association between low education and severe maternal outcomes (adjusted odds ratio, aOR, 2.07; 95% confidence interval, 95% CI, 1.46-2.95), maternal near miss (aOR 1.80; 95% CI 1.25-2.57), and maternal death (aOR 5.62; 95% CI 3.45-9.16) was observed. This relationship persisted in countries with medium HDIs (aOR 2.36; 95% CI 1.33-4.17) and low HDIs (aOR 2.65; 95% CI 1.54-2.57). Less educated women also had increased odds of presenting to the hospital in a severe condition (i.e. with organ dysfunction on arrival or within 24 hours: aOR 2.06; 95% CI 1.36-3.10). The probability that a woman received magnesium sulphate for eclampsia or had a caesarean section significantly increased as education level increased (P < 0.05).

CONCLUSIONS

Women with lower levels of education are at greater risk for severe maternal outcomes, even after adjustment for key confounding factors. This is particularly true for women in countries that have poorer markers of social and economic development.

Development of a non-viral gene delivery vector based on the dynein light chain Rp3 and the TAT peptide

Gene therapy and DNA vaccination trials are limited by the lack of gene delivery vectors that combine efficiency and safety. Hence, the development of modular recombinant proteins able to mimic mechanisms used by viruses for intracellular trafficking and nuclear delivery is an important strategy. We designed a modular protein (named T-Rp3) composed of the recombinant human dynein light chain Rp3 fused to an N-terminal DNA-binding domain and a C-terminal membrane active peptide, TAT. The T-Rp3 protein was successfully expressed in Escherichia coli and interacted with the dynein intermediate chain in vitro. It was also proven to efficiently interact and condense plasmid DNA, forming a stable, small (∼100nm) and positively charged (+28.6mV) complex. Transfection of HeLa cells using T-Rp3 revealed that the vector is highly dependent on microtubule polarization, being 400 times more efficient than protamine, and only 13 times less efficient than Lipofectamine 2000™, but with a lower cytotoxicity. Confocal laser scanning microcopy studies revealed perinuclear accumulation of the vector, most likely as a result of transport via microtubules. This study contributes to the development of more efficient and less cytotoxic proteins for non-viral gene delivery.

Characterization of the human dynein light chain Rp3 and its use as a non-viral gene delivery vector

Dynein light chains mediate the interaction between the cargo and the dynein motor complex during retrograde microtubule-mediated transport in eukaryotic cells. In this study, we expressed and characterized the recombinant human dynein light chain Rp3 and developed a modified variant harboring an N-terminal DNA-binding domain (Rp3-Db). Our approach aimed to explore the retrograde cell machinery based on dynein to enhance plasmid DNA (pDNA) traffic along the cytosol toward the nucleus. In the context of non-viral gene delivery, Rp3-Db is expected to simultaneously interact with DNA and dynein, thereby enabling a more rapid and efficient transport of the genetic material across the cytoplasm. We successfully purified recombinant Rp3 and obtained a low-resolution structural model using small-angle X-ray scattering. Additionally, we observed that Rp3 is a homodimer under reducing conditions and remains stable over a broad pH range. The ability of Rp3 to interact with the dynein intermediate chain in vitro was also observed, indicating that the recombinant Rp3 is correctly folded and functional. Finally, Rp3-Db was successfully expressed and purified and exhibited the ability to interact with pDNA and mediate the transfection of cultured HeLa cells. Rp3-Db was also capable of interacting in vitro with dynein intermediate chains, indicating that the addition of the N-terminal DNA-binding domain does not compromise its function. The transfection level observed for Rp3-Db is far superior than that reported for protamine and is comparable to that of the cationic lipid Lipofectamine™. This report presents an initial characterization of a non-viral delivery vector based on the dynein light chain Rp3 and demonstrates the potential use of modified human light chains as gene delivery vectors.

Enhanced lipidic algae biomass production using gas transfer from a fermentative Rhodosporidium toruloides culture to an autotrophic Chlorella protothecoides culture

In order to produce single-cell oil for biodiesel, a yeast and a microalga were, for the first time, grown in two separate reactors connected by their gas-phases, taking advantage of their complementary nutritional metabolisms, i.e., respiration and photosynthesis. The yeast Rhodosporidium toruloides was used for lipid production, originating a carbon dioxide-enriched outlet gas stream which in turn was used to stimulate the autotrophic growth of Chlorella protothecoides in a vertical-alveolar-panel (VAP) photobioreactor. The microalgal biomass productivity was 0.015 gL(-1)h(-1), and its lipid productivity attained 2.2 mgL(-1)h(-1) when aerated with the outlet gas stream from the yeast fermenter. These values represent an increase of 94% and 87%, respectively, as compared to a control culture aerated with air. The CO2 bio-fixed by the microalgal biomass reached an estimated value of 29 mgL(-1)h(-1) in the VAP receiving the gas stream from the fermenter, a value 1.9 times higher than that measured in the control VAP.

Land application of municipal landfill leachate: fate of ions and ammonia volatilization

Landfill leachates are pollutants rich in ammoniacal N, Na, and K, but land application potentially offers an alternative for recycling these leachate nutrients. We applied landfill leachate corresponding to 0, 110, 220, 330, and 440 kg ha of total N, divided in three applications (July, August, and October 2008), onto the surface of an acidic (pH 5.5-6.0) clay (79% clay) Ultisol and monitored NH volatilization just after applications and microbiological (0-10 cm) and chemical attributes (0-60-cm soil depth) in August 2008, January 2009, and May 2009. Ammonium (up to 30 mg kg), NO (up to 160 mg kg), Na, K (up to 1.1 cmol kg each), and electrical conductivity (up to 1 dS m) increased transiently in soil following applications. Despite >90% of the total leachate N being ammoniacal, NO predominated in the first soil sampling, 14 d after the second application, suggesting fast nitrification, but it decreased in the soil profile thereafter. From 5 to 25% of the total applied N volatilized as NH, with maximum losses within the first 3 d. Applications inhibited (50%) the relative nitrification rate and increased (50%) hot-water-soluble carbohydrates in the soil at the highest rate. No effects were observed on soil microbial biomass C (114-205 mg kg) and activity (5-8 mg CO-C kg d) or on corn grain yields (6349-7233 kg ha). Controlled land application seems to be a viable alternative for landfill leachate management, but NO leaching, NH volatilization, and accumulation of salinizing ions must be monitored in the long term to prevent environmental degradation.

Ammonia volatilization in soil treated with tannery sludge

The utilization of tannery sludge in agricultural areas can be an alternative for its disposal and recycling. Despite this procedure may cause the loss of nitrogen by ammonia volatilization, there is no information about this process in tropical soils. For two years a field experiment was carried out in Rolândia (Paraná State, Brazil), to evaluate the amount of NH(3) volatilization due to tannery sludge application on agricultural soil. The doses of total N applied varied from zero to 1200 kg ha(-1), maintained at the surface for 89 days, as usual in this region. The alkalinity of the tannery sludge used was equivalent to between 262 and 361 g CaCO(3) per kg. Michaelis-Menten equation was adequate to estimate NH(3)-N volatilization kinetics. The relation between total nitrogen applied as tannery sludge and the potentially volatilized NH(3)-N, calculated by the chemical-kinetics equation resulted in an average determination coefficient of 0.87 (P>0.01). In this period, the amount of volatilized NH(3) was more intense during the first 30 days; the time to reach half of the maximum NH(3) volatilization (K(m)) was 13 an 9 days for the first and second experiments, respectively. The total loss as ammonia in the whole period corresponded in average to 17.5% of the total N applied and to 35% of the NH(4)(+)-N present in the sludge. If tannery sludge is to be surface applied to supply N for crops, the amounts lost as NH(3) must be taken into consideration.

Evaluation of anhydride oligomers within polymer microsphere blends and their impact on bioadhesion and drug delivery in vitro

The effect of the addition of small molecular weight anhydride oligomers to polymer microspheres was evaluated and increased bioadhesion of the composite was demonstrated. Blends of low molecular weight anhydride oligomers with thermoplastic poly(fumaric-co-sebacic anhydride) [p(FASA)] and polycaprolactone were examined. The effects of anhydride oligomers on polymer microsphere degradation, crystallinity, and surface morphology were also explored. The results demonstrated that fumaric anhydride oligomer remained within polymer microspheres for several hours after exposure to phosphate buffer, formed a homogenous crystalline blend, increased bioadhesion as measured on rat intestine, and enhanced drug delivery in vitro as measured by the everted sac technique.

[Mother-infant indicators in adolescence and youth: socio-demographic, prenatal, delivery and newborns]

OBJECTIVE: To identify characteristics and associations between maternal age and gestation, delivery, and livebirths of adolescent and young adult mothers in the city of Feira de Santana, state of Bahia, Brazil. METHODS: We carried out a cross-sectional, epidemiological study with a population of livebirths and adolescent mothers (aged 10-16 and 17-19 years) and young adult mothers (aged 20-24 years). The information were obtained from the Livebirths Information System (SINASC-1998) for a total of 5,279 livebirths. Study variables were classified into socio-demographic factors (age, schooling of the mother, sex of the newborn) and related to term, delivery, gestational age, birth weight, and Apgar score. Data were processed using prevalence ratio and multivariate analysis. Logistic regression was used to control confounding factors (prenatal and gestational age) and to establish an association between maternal age and birth weight. RESULTS: In 1998, 21.6% of all livebirths in the city of Feira de Santana were from adolescent mothers; out of these mothers, 51.2% had not finished junior high or elementary school. Prevalence ratio and adjusted odds ratio for the 10-16 years of age group indicated increased prevalence of illiteracy, no prenatal examination, and low birth weight and a low prevalence of adequate weight of the newborn in comparison to other age groups studied. Logistic regression showed a positive association between maternal age and low birth weight. We also observed that the SINASC database lacked information in many different fields. CONCLUSIONS: Our results indicated, for adolescent mothers, a high prevalence of livebirths and low schooling. Also, especially for the 10-16 years of age group, we observed increased risks for illiteracy, no prenatal examinations, low birth weight, and inadequate weight of the newborn in comparison to other age groups.

Lower hookworm incidence, prevalence, and intensity of infection in children with a Bacillus Calmette-Guérin vaccination scar

Bacillus Calmette-Guérin (BCG), the most common vaccine worldwide, has broad effects on the immune system. Hookworm infections are a major source of morbidity. In response to a preliminary report of BCG vaccination protection against nematodes in human immunodeficiency virus-infected adults, data from an ongoing prospective study were analyzed to determine the intensity (eggs per gram of stool), prevalence, and incidence of different helminths in children with and without a BCG vaccination scar. Adjusted prevalence and incidence ratios were estimated by using logistic regression. Children with a BCG vaccination scar were found to have statistically significantly lower hookworm prevalence (41%), incidence (37%), and mean egg counts (39%), after controlling for age, sex, and socioeconomic factors. There was no BCG association with incidence, prevalence, or intensity of infection with Schistosoma mansoni, Ascaris lumbricoides, or Trichuris trichiura. Such protection would have implications for public health and for research on mechanisms behind human immunological responses to hookworm.

Uleine and demethoxyaspidospermine from the bark of Plumeria lancifolia

The isolation of (+)-uleine (1) and (+)-demethoxyaspidospermine (2) from the bark of Plumeria lancifolia is reported along with (1)H- and (13)C-NMR data.

Correlation of two bioadhesion assays: the everted sac technique and the CAHN microbalance

This contribution correlates two in vitro methods utilized to determine bioadhesion. One method, the everted intestinal sac technique, is a passive test for bioadhesion involving several polymer microspheres and a section of everted intestinal tissue. The other method, the CAHN microbalance, employs a CAHN dynamic contact angle analyzer with modified software to record the tensile forces measured as a single polymer microsphere is pulled from intestinal tissue. This study demonstrates that CAHN and everted sac experiments yield similar results when used to quantify the bioadhesive nature of polymer microsphere systems. A polymer showing high adhesion in one method also demonstrates high bioadhesion in the other method; polymers that exhibit high fracture strength and tensile work measurements with the CAHN microbalance also yield high binding percentages with the everted sac method. The polymers tested and reported here are poly(caprolactone) and different copolymer ratios of poly(fumaric-co-sebacic anhydride). The results of this correlation demonstrate that each method alone is a valuable indicator of bioadhesion.

Poly(fumaric-co-sebacic anhydride). A degradation study as evaluated by FTIR, DSC, GPC and X-ray diffraction

The degradation of three poly(fumaric-co-sebacic anhydride) [P(FA:SA)] copolymers is examined in a composition of microspheres made by the hot melt encapsulation process. The emergence of low molecular weight oligomers occurs during degradation of the copolymer microspheres, as evidenced by a variety of characterization methods. Characterization was conducted to determine the extent of degradation of the polyanhydride microspheres using Fourier-transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and X-ray diffraction. It is demonstrated that degradation of P(FA:SA) is greatly accelerated at basic pH, yet there is little difference between degradation in neutral and acidic buffers. A good correlation exists between the results of each characterization method, which allows a better understanding of the degradation process and the resulting formation of low molecular weight oligomers in poly(fumaric-co-sebacic anhydride).

[Violence, ethnic groups and skin color: a study on differences in the metropolitan region of Salvador, Bahia, Brazil]

The objective of this study was to analyze the distribution of various forms of violence--structural, institutional, interpersonal, and crime-related--in the three most common color groups of Bahian society: mulattos, whites, and blacks. The study compared the levels of victimization of mulatto, white, and black individuals with their assessments of the efficiency of crime-control institutions, in order to ascertain how that relates to those same citizens' acceptance of authoritarian attitudes and norms. The data analyzed came from the multicenter project on Attitudes and Cultural Standards about Violence (ACTIVA) project, from a sample of 1,384 residents of the Salvador metropolitan region. The study was designed as a cross-sectional survey, with interviews done in the people's homes between September and December of 1996. The sample selection was done in three stages: first, residential areas were chosen at random; then, a systematic selection was made from the homes in each of the selected areas; finally, the persons to be interviewed were chosen at random. To collect the data the researchers used a pretested questionnaire that had been designed for the ACTIVA study. The results showed an unequal distribution of structural violence that mainly affected blacks. There were no differences by color group for interpersonal and institutional violence. Criminal violence impacted whites and blacks to the same degree. Distrust in the efficiency of the civil and military police and in the justice and penal systems was very high among all three color groups. Moreover, few differences were found among the groups with regard to authoritarian attitudes and norms. Based on the results, it is possible to conclude that public order is threatened if the dissatisfaction with institutions for crime prevention and reduction continues at a high level at the same time that individuals tend to support violence to resolve conflicts.

Measuring the burden of common morbidities: sampling disease experience versus continuous surveillance

Longitudinal prevalence, the proportion of all days of observation that a given individual manifests symptoms of illness, is a measure of disease frequency that is easy to generate from daily morbidity data and has been shown to be strongly related to subsequent health outcome. It is hypothesized that this measure could be derived using a representative sample of days of observation rather than continuous surveillance. The authors use 1990-1991 data from a Brazilian supplementation trial comprising a year's daily records of the occurrence of diarrhea, fever, and cough in 906 children under 5 years of age to examine how many days of morbidity data need to be observed to rank subjects into quintiles of illness frequency. Systematic samples of the full data set, based on every 2nd, 3rd, 5th, 10th, 15th, 20th, and 30th day of data, are compared with the continuous record. For diarrhea and fever, estimates based on less than 72 days of observation result in over one fourth of individuals who should have been in the extreme quintiles of the morbidity distribution being misclassified, and over one fifth of all subjects appear (falsely) to suffer no morbidity. Estimates of longitudinal prevalence should be based on at least 72 days of observation.

Cytokine immunotherapy of cancer with controlled release biodegradable microspheres in a human tumor xenograft/SCID mouse model

A novel biodegradable poly(lactic acid) microsphere formulation was evaluated for in vivo cytokine immunotherapy of cancer in a human tumor xenograft/ severe combined immunodeficiency (SCID) mouse model. Co-injection of interleukin-2 (IL-2)-loaded microspheres with tumor cells into a subcutaneous site resulted in the complete suppression of tumor engraftment in 80% of animals. In contrast, bovine-serum-albumin(BSA)-loaded particles or bolus injections of poly(ethylene glycol)/IL-2 were ineffective in preventing tumor growth. The antitumor effect of IL-2 released by the microspheres was shown to be mediated by the mouse natural killer cells. This is the first evidence that the rejection of human tumor xenografts can be provoked by the sustained in vivo delivery of IL-2 from biodegradable microspheres. The use of poly(lactic acid) microspheres to deliver cytokines to the tumor environment could provide a safer and simpler alternative to gene therapy protocols in the treatment of cancer.

Biologically erodable microspheres as potential oral drug delivery systems

Biologically adhesive delivery systems offer important advantages over conventional drug delivery systems. Here we show that engineered polymer microspheres made of biologically erodable polymers, which display strong adhesive interactions with gastrointestinal mucus and cellular linings, can traverse both the mucosal absorptive epithelium and the follicle-associated epithelium covering the lymphoid tissue of Peyer's patches. The polymers maintain contact with intestinal epithelium for extended periods of time and actually penetrate it, through and between cells. Thus, once loaded with compounds of pharmacological interest, the microspheres could be developed as delivery systems to transfer biologically active molecules to the circulation. We show that these microspheres increase the absorption of three model substances of widely different molecular size: dicumarol, insulin and plasmid DNA.

Hepatitis G virus/GB virus C in Brazil. Preliminary report

Hepatitis G virus/GB virus C is a novel flavivirus recently detected in hepatitis non A-E cases. In this study, the presence of this virus in chronic non-B, non-C hepatitis patients was evaluated using GBV-C specific PCR and this virus was detected in one out of thirteen patients. This patient has presented a severe liver failure, has lived for a long time in the Western Amazon basin and no other cause for this clinical picture was reported. The impact of the discovery of this new agent is still under evaluation throughout the world. The study of the prevalence of this virus among chronic hepatitis patients and healthy individuals (as blood donors) will furnish subside to evaluate its real pathogenicity.

[Myocardial revascularization in left coronary trunk lesion in patients over 65 years old]

PURPOSE

To study the short and long-term follow-up of patients with left main coronary artery disease (LMCAD) and age over 65 years, by comparing the results with patients under 65 years-old.

METHODS

Twenty-two patients with LMCAD and mean age of 69 +/- 3.5 years (group I) were underwent isolated coronary artery bypass grafting (CABG) and compared to 31 patients with LMCAD, mean age of 54 +/- 7 years (group II), who also underwent isolated CABG. The life-table Kaplan-Meyer method was used to estimate the post-operative survival. The chi-square and Student "t" test were used when necessary.

RESULTS

Despite higher operative mortality in group I (9.1% x 3.2%), the difference was statistically not significant. The operative morbidity was similar in both groups. Actuarial survival at 4 years was 85% in group I and 95% in group II. Actuarial survival free of cardiac events was 69% in group II and 75% in group II.

CONCLUSION

The CABG is well tolerated and had low morbidity and acceptable mortality in old patients with LMCAD. The long-term survival in these patients was very similar to the younger patients.

Detection of hepatitis B virus DNA by the polymerase chain reaction in anti-HBe positive chronic hepatitis B patients

Detection of HBV-DNA by PCR was compared with other serological markers (HBsAG, HBeAg and anti-HBe) in a series of 49 Chronic Hepatitis B patients, including 12 with a spontaneous clearance of HBsAg. None of these HBsAg negative cases were PCR positive, but 33/37 (89.2%) HBsAg positive cases were PCR positive (p < 0.0001). Among HBsAg positive samples, nine cases were HBeAg positive and anti-HBe negative, all of them PCR positive. Other 3 patients were HBeAg and anti-HBe positive and these cases were also found PCR positive. A third group included 21 patients anti-HBe positive and HBeAg negative: 19 of them were PCR positive and 2 were PCR negative. The last 4 cases were HBeAg and anti-HBe negative, two of them were PCR positive. The detection of anti-HBe viremic cases in the present series suggest that preC variants could occur in our country. In conclusion, the integrated phase of chronic hepatitis B seems to be less frequent than it was assumed, when only HBeAg or dot blot hybridization techniques were used. The new term "low replication phase" might favorably replace the former "integrated phase".

Evaluation of pulmonary systemic blood flow using ECG gated acquisition

We propose a functional parametric analysis method using ECG-gated 99mTc-labeled red blood cell (RBC) imaging for detection and characterization of periodic variations in local blood activity in the lungs during cardiac cycle. We validated in animal experiments that such count variations correlate with cyclical pulmonary blood flow and may be used for evaluation of systemic-to-pulmonary shunts. Clinical studies were performed in 48 patients. After labeling the RBC pool with 99mTc, ECG-gated gamma camera images of both lung fields were acquired and processed to obtain Fourier transforms of time/activity functions in selected regions. The first harmonic parametric images of amplitude and phase were derived. There was an excellent correlation (r = 0.92) between activity variations and pulsatile flow measured by our method with that obtained by the thermodilution method in dog experiments (n = 10) after implantation of a systemic-to-pulmonary shunt. Patient studies showed the technique to be sensitive in detecting and quantifying abnormal systemic-to-pulmonary blood flow. Lung pulsatile flow can thus be noninvasively measured from functional parametric phase and amplitude images; the technique may be useful for detecting and quantifying abnormal systemic-to-pulmonary blood flow in man.

Effects of methadone on behavior maintained by fixed ratio reinforcement schedules

The effects of subcutaneous injections of methadone hydrochloride (0.75mg, 1.5mg and 2.5mg/kg) on lever pressing maintained by fixed ratio schedules of reinforcement were examined in C57BL/6J and DBA/2J mice. Response output over a 30 min session decreased as a function of increasing drug dose when reinforcement was delivered for every 5 responses. Increasing the response to reinforcement ratio from 5 to 20 in a second experiment doubled and nearly quadrupled responding by DBA and C57 mice, respectively. Injecting animals maintained on this schedule with methadone reduced responding to the same extent as that observed in the first experiment when response rates were lower. Hence, these experiments provide no support for the effect of methadone being rate-dependent. In both experiments methadone disrupted responding of DBA more than that of C57 mice. This finding is consistent with a previous report that other narcotic analgesics were more potent analgesics for DBA than for C57 mice. From these studies it appears that the opposite changes in locomotor activity upon an exposure to narcotic analgesics does not generalize to behavior under control of reinforcing stimuli; and that both the effects obtained in the present study and the analgesic action are dissociated from the effects of these drugs on locomotor activity.

Phenobarbital during pregnancy alters operant behavior of offspring in C57BL/6J mice

Offspring of C57BL/6J injected daily with phenobarbital for the last third of pregnancy responded less than control animals when maintained on various fixed ratio schedules of reinforcement. The response decrement became more pronounced as the schedule demands were increased and was noted in offspring of both sexes. The higest dose (80 mg/kg) was less effective than the 2 lower doses (20 mg and 40 mg/kg) in producing the decrement which may reflect a selection factor due to high neonatal mortality previously reported at this dose. The study provides no evidence of the mechanism mediating the long term behavioral abnormality but does clearly extend the finding of such changes to doses which do not produce increased neonatal mortality or noticeable morphological changes.

Effects of phenobarbital given to pregnant mice on behavior of mature offspring

Mature offspring of C57BL/6J mice (Mus musculus) injected daily with phenobarbital (40 mg/kg) for the last third of pregnancy differed from saline and untreated control animals on 3 measures of behavior. Offspring of phenobarbital treated animals had higher locomotor scores than controls during an open field activity test at 75 days of age. Male offspring were also tested on a 1-trial passive avoidance task and treated animals were found to be deficient. Finally, female offspring responded less than controls on fixed ratio schedules of reinforcement. The behavioral changes suggest that offspring of mice injected with phenobarbital during pregnancy are less responsive to the stimuli in their environment which maintain behavior.