Epidemiology of enterotoxigenic Escherichia coli and impact on the growth of children in the first two years of life in Lima, Peru

Background

Enterotoxigenic E. coli (ETEC) is a leading cause of diarrheal morbidity and mortality in children, although the data on disease burden, epidemiology, and impact on health at the community level are limited.

Methods

In a longitudinal birth cohort study of 345 children followed until 24 months of age in Lima, Peru, we measured ETEC burden in diarrheal and non-diarrheal samples using quantitative PCR (LT, STh, and STp toxin genes), studied epidemiology and measured anthropometry in children.

Results

About 70% of children suffered from one or more ETEC diarrhea episodes. Overall, the ETEC incidence rate (IR) was 73 per 100 child-years. ETEC infections began early after birth causing 10% (8.9-11.1) ETEC-attributable diarrheal burden at the population level (PAF) in neonates and most of the infections (58%) were attributed to ST-ETEC [PAF 7.9% (1.9-13.5)] and LT + ST-ETEC (29%) of which all the episodes were associated with diarrhea. ETEC infections increased with age, peaking at 17% PAF (4.6-27.7%; p = 0.026) at 21 to 24 months. ST-ETEC was the most prevalent type (IR 32.1) with frequent serial infections in a child. The common colonization factors in ETEC diarrhea cases were CFA/I, CS12, CS21, CS3, and CS6, while in asymptomatic ETEC cases were CS12, CS6 and CS21. Only few (5.7%) children had repeated infections with the same combination of ETEC toxin(s) and CFs, suggested genotype-specific immunity from each infection. For an average ETEC diarrhea episode of 5 days, reductions of 0.060 weight-for-length z-score (0.007 to 0.114; p = 0.027) and 0.061 weight-for-age z-score (0.015 to 0.108; p = 0.009) were noted in the following 30 days.

Conclusion

This study showed that ETEC is a significant pathogen in Peruvian children who experience serial infections with multiple age-specific pathotypes, resulting in transitory growth impairment.

Can COVID-19 pandemic worsen previous neurological/psychiatric diseases?

Introduction

The SARS-CoV-2 pandemic has been affecting the world since January 2020. Although its pathogenesis is primarily directed to the respiratory tract, other organs may be affected, including the nervous system. It has also been shown that the social context (confinement, lack of treatment) has affected neurological patients during this period. The aim of the study it was to assess the subjective worsening of neurological/psychiatric diseases in the context of the SARS-Cov-2 pandemic.

Methods

Three groups of neurological/psychiatric patients were included: Patients who had symptomatic COVID-19 (n = 89), patients who had asymptomatic COVID-19 (n = 40), and a control group (n = 47), consisting of neurological/psychiatric patients without a history of SARS-Cov-2 infection.

Results

30.7% of the included individuals considered that their basal pathology had worsened during the study period. This feeling was significantly more frequent (P = 0.01) in patients with symptomatic COVID-19 (39.3%) than in patients of the other 2 groups (21.8%). Worsening was not related to the severity of COVID-19. The neurological conditions that significantly worsened after COVID-19, comparing symptomatic COVID-19 with the other 2 groups, were demyelinating and degenerative diseases.

Conclusions

These results confirmed the impact of the SARS-Cov-2 pandemic on patients with neurological/psychiatric diseases. Confinement, lack of medical care, and the threat of diagnosis are surely contributing factors. Although the finding of a higher frequency of worsening in symptomatic COVID-19 patients may be related to greater anxiety/depression in this group of patients, we cannot exclude the role of direct affectation of the nervous system by the virus or damage due to neuroinflammation.

Merlin modulates process outgrowth and synaptogenesis in the cerebellum

Neurofibromatosis type 2 (NF2) patients are prone to develop glial-derived tumors in the peripheral and central nervous system (CNS). The Nf2 gene product -Merlin is not only expressed in glia, but also in neurons of the CNS, where its function still remains elusive. Here, we show that cerebellar Purkinje cells (PCs) of isoform-specific Merlin-deficient mice were innervated by smaller vGluT2-positive clusters at presynaptic terminals than those of wild-type mice. This was paralleled by a reduction in frequency and amplitude of miniature excitatory postsynaptic currents (mEPSC). On the contrary, in conditional transgenic mice in which Merlin expression was specifically ablated in PCs (L7Cre;Nf2^fl/fl), we found enlarged vGluT2-positive clusters in their presynaptic buttons together with increased amplitudes of miniature postsynaptic currents. The presynaptic terminals of these PCs innervating neurons of the deep cerebellar nuclei were also enlarged. When exploring mice with Merlin-deficient granule cells (GCs) (Math1Cre;Nf2^fl/fl), we found cerebellar extracts to contain higher amounts of vGluT1 present in parallel fiber terminals. In parallel, mEPSC frequency was increased in Math1Cre;Nf2^fl/fl mice. On the contrary, VGluT2 clusters in cerebellar glomeruli composed of NF2-deficient presynaptic Mossy fiber terminals and NF2-deficient postsynaptic GC were reduced in size as shown for isoform-specific knockout mice. These changes in Math1Cre;Nf2^fl/fl-deficient mice were paralleled by an increased activation of Rac1-Cofilin signaling which is known to impact on cytoskeletal reorganization and synapse formation. Consistent with the observed synaptic alterations in these transgenic mice, we observed altered ultrasonic vocalization, which is known to rely on proper cerebellar function. No gross morphological changes or motor coordination deficits were observed in any of these transgenic mice. We therefore conclude that Merlin does not regulate overall cerebellar development, but impacts on pre- and post-synaptic terminal organization.

The Benefits of Peer Review and a Multisemester Capstone Writing Series on Inquiry and Analysis Skills in an Undergraduate Thesis

This study examines the relationship between the introduction of a four-course writing-intensive capstone series and improvement in inquiry and analysis skills of biology senior undergraduates. To measure the impact of the multicourse write-to-learn and peer-review pedagogy on student performance, we used a modified Valid Assessment of Learning in Undergraduate Education rubric for Inquiry and Analysis and Written Communication to score senior research theses from 2006 to 2008 (pretreatment) and 2009 to 2013 (intervention). A Fisher-Freeman-Halton test and a two-sample Student's t test were used to evaluate individual rubric dimensions and composite rubric scores, respectively, and a randomized complete block design analysis of variance was carried out on composite scores to examine the impact of the intervention across ethnicity, legacy (e.g., first-generation status), and research laboratory. The results show an increase in student performance in rubric scoring categories most closely associated with science literacy and critical-thinking skills, in addition to gains in students' writing abilities.

Francisella species in ticks and animals, Iberian Peninsula

The presence of Francisella species in 2134 ticks, 93 lagomorphs and 280 small mammals from the Iberian Peninsula was studied. Overall, 19 ticks and 6 lagomorphs were positive for Francisella tularensis subsp. holarctica, suggesting, as described for other regions, that lagomorphs may have an important role in the maintenance of F. tularensis in nature. Of the 6 positive lagomorphs, 4 were identified as the European rabbit, Oryctogalus cuniculus. Additionally, 353 ticks and 3 small mammals were PCR positive for Francisella-like endosymbionts (FLEs) and one small mammal was also positive for Francisella hispaniensis-like DNA sequences. Among FLE positive specimens, a variety of sequence types were detected: ticks were associated with 5 lpnA sequence types, with only one type identified per tick, in contrast to 2 lpnA sequence types detected in a single wood mouse (Apodemus sylvaticus). To our knowledge, this is the first report of FLEs in free-living small mammals as well as the first detection of F. hispaniensis-like sequences in a natural setting.

Phylogenetic analysis of a virulent Borrelia species isolated from patients with relapsing fever

Multilocus sequence analysis (MLSA) was used to clarify the taxonomic status of a virulent Borrelia organism previously isolated from patients with relapsing fever and from ticks in Spain that is designated the Spanish relapsing fever (SRF) Borrelia. This species has been used extensively in experimental infection models because of its continued virulence. Seven genes were amplified to analyze the phylogenetic relationships among several Spanish isolates of SRF Borrelia and other relapsing fever Borrelia species. The genes targeted in this study included rrs and flaB, which have commonly been used in phylogenetic studies; the rrf-rrl intergenic spacer (IGS), which is highly discriminatory; and four additional genes, p66, groEL, glpQ, and recC, which are located on the chromosome and which have therefore evolved in a clonal way. The species included in this study were Borrelia duttonii, B. recurrentis, B. crocidurae, and B. hispanica as Old World Borrelia species and B. turicatae and B. hermsii as New World Borrelia species. The results obtained by MLSA of the SRF Borrelia on the basis of 1% of the genomic sequence data analyzed confirmed that the SRF Borrelia isolates are B. hispanica. However, the prototype isolates of B. hispanica used in this study have an uncertain history and display unique phenotypic characteristics that are not shared with the SRF Borrelia. Therefore, we propose to use strain SP1, isolated from a relapsing fever patient in 1994 in southern Spain, as the type strain for B. hispanica.

[25 hydroxyvitamin D levels and cardiovascular risk in a cohort of patients with advanced chronic kidney disease]

BACKGROUND

Decreased 25 hydroxyvitamin D serum levels have been related to an increase in cardiovascular morbility and mortality in both general population and chronic kidney disease patients. The aim of this study was to evaluate the relationship between 25 hydroxyvitamin D serum level, cardiovascular risk factors and previous established cardiovascular disease in a group of patients with advanced chronic kidney disease.

MATERIAL AND METHODS

We performed a cross-sectional observational study in a cohort of 171 stage 4 and 5 chronic kidney disease outpatients seen in our predialysis clinic, mean age 64.16 +/- 13 years, 59.6% were men, 64.3% had diabetes, 47.3% had obesity, 46.8% had previous cardiovascular disease. 25 hydroxyvitamin D and 1-25 dihydroxyvitamin D were measured, we also determined other routine biochemical parameters. All subjects underwent an echocardiogram and 24 hours ambulatory blood pressure monitoring was also performed.

RESULTS

Mean 25 hydroxyvitamin D levels were 22.1 +/- 13 ng/mL, only 18.7% of the patients had adequate levels, levels were insufficient in 58.5% of the patients and deficient in 22.8% of them. Low 25 hydroxyvitamin D levels were significantly related with age, diabetes, female gender, obesity, MDRD glomerular filtration rate and previous cardiovascular disease. Pulse pressure was the Ambulatory Blood Pressure Monitoring parameter that was better correlated with 25 hydroxyvitamin D levels. We could not find any association between vitamin D levels and other bone and mineral metabolism parameters. No relationship was seen between low vitamin D levels and left ventricular hypertrophy. On multivariate analysis lower levels of 25 hydroxyvitamin D were independently associated with female gender, previous cardiovascular disease, MDRD4-GFR and higher pulse pressure.

CONCLUSIONS

Our study confirm a high prevalence of 25 hydroxyvitamin D insufficiency and deficiency in advanced chronic kidney disease patients, this was associated with the presence of cardiovascular risk markers and previous established cardiovascular disease. However we could not see any relationship with left ventricular hypertrophy which is a known predictor of future cardiovascular events in this population.

A possible novel Francisella genomic species isolated from blood and urine of a patient with severe illness

Two identical isolates were recovered in pure culture from the blood and urine of a patient suffering from severe septicaemia associated with obstructive pyelonephritis secondary to lithotripsy. Preliminary phenotypic and genotypic characterizations based on serological, biochemical and sequence analyses following PCR amplification of selected gene regions indicate that this organism represents a potential new Francisella genomic species.

Further evaluation of the synthetic peptide vaccine S3Pvac againstTaenia soliumcysticercosis in pigs in an endemic town of Mexico

Taenia soliumcysticercosis is a parasitic disease frequently affecting human health and the pig industry in many developing countries. A synthetic peptide vaccine (designated S3Pvac) against porcine cysticercosis has been developed previously as an aid to interrupt transmission and has been shown to be effective. The results of the present study support the effectiveness of the vaccine under endemic field conditions. However, given the time-frame of the vaccination trial, no changes in the local levels of transmission were detectable before and after vaccination using sentinel pigs. Thus, this investigation shows the limited usefulness of single vaccination as the sole means of interruptingTaenia soliumtransmission in an endemic region.

Intrahepatic DNA vaccination: unexpected increased resistance against murine cysticercosis induced by non-specific enhanced immunity

Experimental murine cysticercosis caused by Taenia crassiceps has proved to be a useful model with which to test the efficacy of new vaccine candidates and delivery systems against pig cysticercosis. A high level of protection against murine cysticercosis was previously observed by intramuscular or intradermal DNA immunization with the use of the sequence of the recombinant KETc7 antigen cloned in pcDNA3 (pTc-sp7). To determine the effect of KETc7 differential expression in DNA vaccination, KETc7 was cloned in pGEM 11Zf(+) under the control of the tissue-specific regulatory promoter phosphoenolpyruvate carboxykinase (pPc-sp7). A high level of protection was induced by intrahepatic immunization with pPc-sp7, pTc-sp7 and the empty vector in the absence of any specific immunity. The empty vector pGEM 11Zf(+), the plasmid with the highest content of CpG sequences, provided to the most efficient protection. This protection was related to an increased number of splenocytes, enhanced nonspecific splenocyte proliferation, and intensified intrahepatic INF-gamma production. Overall, intrahepatic plasmid CpG-DNA immunization provokes an exacerbated nonspecific immune response that can effectively control Taenia crassiceps cysticercosis.

Effective Protection Against Experimental Taenia solium Tapeworm Infection in Hamsters by Primo-Infection and by Vaccination with Recombinant or Synthetic Heterologous Antigens

The disease caused by Taenia solium is progressively being recognized as a growing global threat for public human health and pig husbandry that requires the development of effective control measures. A central participant in the taeniasis/cysticercosis transmission network is the human carrier of the adult tapeworm because of its great potential in spreading the infection. Herein, evidence is presented that a primary infection of golden hamsters with orally administered T. solium cysticerci improved the host's resistance against a secondary infection. Likewise, previous vaccination increased the hamster's resistance. Similar high levels of protection (> 78%) were induced by systemic or oral vaccination with the S3Pvac anticysticercosis synthetic peptide vaccine or the highly immunogenic recombinant chimera based on the protective peptide KETc1 bound to Brucella spp. lumazine synthase (BLS-KETc1). Increased resistance after primo-infection and vaccination possibly results from changes in the immune conditions prevailing in the host's intestine. The contribution to protection from the KETc1 and BLS epitopes in a chimeric vaccine is under study. Preventive vaccination of definitive hosts of T. solium against the tapeworm, the most relevant step in the taeniasis/cysticercosis transmission, may greatly impact the dynamics of endemic disease and has not been studied or tried previously.

A novel synthetic adjuvant effectively enhances the immunogenicity of the influenza vaccine

Influenza vaccination is a key intervention to reduce morbidity and mortality provoked by this disease. To date, the challenge of improving its efficacy remains unmet. The immunogenic synthetic peptide GK1 from Taenia crassiceps cysticerci was tested herein in its capacity as adjuvant, co-administered with the inactivated anti-influenza vaccine before and after challenge with influenza virus in both young and aged mice. Co-administration of GK1 with the influenza vaccine increased levels of anti-influenza antibodies in aged mice before and after infection, reduced the local inflammation that accompanied influenza vaccination itself and favored virus clearance after infection in both young and aged mice.

Improvement of the neighborhood based Levenberg-Marquardt algorithm by local adaptation of the learning coefficient

In this letter, an improvement of the recently developed neighborhood-based Levenberg-Marquardt (NBLM) algorithm is proposed and tested for neural network (NN) training. The algorithm is modified by allowing local adaptation of a different learning coefficient for each neighborhood. This simple add-in to the NBLM training method significantly increases the efficiency of the training episodes carried out with small neighborhood sizes, thus, allowing important savings in memory occupation and computational time while obtaining better performance than the original Levenberg-Marquardt (LM) and NBLM methods.

Bioavailability of ranitidine in healthy Mexican volunteers: effect of food

Is well known that food can affect the bioavailability of several drugs, its impact is major for those drugs that have to act near of drug absorption. Documentation about alterations of ranitidine bioavailability by effect of food is poor. The purpose of this work was to evaluate the effect of food over the bioavailability of ranitidine. Twenty healthy Mexican volunteers were included for the study. The study was made in two stages, in the first one the volunteers had 12 hour fast and took a 300 mg of oral dose of ranitidine (without food, WOF) and blood samples were drawn. Two weeks later, the volunteers took a normal diet just before ranitidine intake (with food, WF). The area under the curve (AUC) was 30% greater in WOF, Cmax was 921.5 ng/ml (WF) vs. 1685.2 (WOF), and t1/2 was 2.70 +/- 1.38 (WF) h vs 3.66 +/- 1.34 (WOF). The AUC, Cmax and t1/2 were statistically different. It is evident that there are differences in the drug disposition due to the presence of food, then, it is possible that the efficacy of ranitidine as inhibitor of gastric secretion being limited by food.

Synthetic peptide vaccine against Taenia solium pig cysticercosis: successful vaccination in a controlled field trial in rural Mexico

Taenia solium cysticercosis seriously affects human health when localised in the central nervous system (CNS) and causes great economic loss in pig husbandry in rural areas of endemic countries. Increasing the resistance to the parasite in the obligatory host pig may help in curbing transmission. Three synthetic peptides based on protein sequences of the murine parasite Taenia crassiceps, which had previously been shown to induce protection in mice against homologous challenge, were tested as a vaccine against T. solium cysticercosis in pigs. Vaccinated and unvaccinated piglets (240 in all) were distributed in pairs among the peasants' households of two rural villages in Mexico in which 14% of the native pigs were cysticercotic. Ten to twelve months later, the effect of vaccination was evaluated at necropsy. Vaccination decreased the total number of T. solium cysticerci (98.7%) and reduced the prevalence (52.6%). The natural challenge conditions used in this field trial strengthen the likelihood of successful transmission control to both pig and human through a large-scale pig vaccination program. We believe this is a major contribution in anticysticercosis vaccine development as these rather simple yet protective peptides are potentially more cost-effective to produce and less variable in results than antigens that are more complex.

Inhibitory role of antibodies in the development of Taenia solium and Taenia crassiceps toward reproductive and pathogenic stages

Untreated Taenia solium cysticerci obtained from different naturally infected pigs vary notably in their capacity to develop into intestinal tapeworms in prednisolone-treated hamsters, whereas cells derived from Taenia crassiceps cysticerci after 2 mo of infection almost always develop to cysticerci in the peritoneal cavity of susceptible BALB/cAnN mice. Preincubation of whole cysticerci or parasite cells with mice immunoglobulins raised against an 18-mer peptide epitope (GK-1) common to both parasites significantly interferes with both transformations. These crippling effects of antiparasite antibodies suggest new forms of immunological interference with parasite biology other than simple killing. Antibodies that cripple biological functions of the parasite, e.g., their development to reproductive or pathogenic stages, make them important protagonists in taeniasis/cysticercosis disease as classic parasitocidal antibodies. Different serum levels of crippling antibodies in the infected pigs could be responsible for the varied ability of cysticerci to convert to tapeworms. Antigens capable of inducing crippling antibodies, e.g., GK-1, could be useful as a therapeutic vaccine for pigs in order to reduce parasite transmission.

Two epitopes shared by Taenia crassiceps and Taenia solium confer protection against murine T. crassiceps cysticercosis along with a prominent T1 response

Taenia crassiceps recombinant antigens KETc1 and KETc12 have been shown to induce high level of protection against experimental murine T. crassiceps cysticercosis, an experimental model successfully used to test candidate antigens for use in vaccination against porcine Taenia solium cysticercosis. Based on the deduced amino acid sequence, KETc1 and KETc12 were chemically synthesized in linear form. Immunization with KETc1 induced 66.7 to 100% protection against murine cysticercosis, and immunization with KETc12 induced 52.7 to 88.1% protection. The elicited immune response indicated that both peptides contain at least one B-cell epitope (as demonstrated by their ability to induce specific antibodies) and one T-cell epitope that strongly stimulated the proliferation of T cells primed with either the free peptide or total cysticercal T. crassiceps antigens. The high percentage of spleen cells expressing inflammatory cytokines points to the likelihood of a T1 response being involved in protection. The protective capacity of the peptides and their presence in all developmental stages of T. solium point to these two epitopes as strong candidates for inclusion in a polyepitopic synthetic vaccine against T. solium pig cysticercosis.

[Respiratory failure in the Guillain Barré syndrome]

Severe involvement of the respiratory muscles is seen in 25% of patients with a diagnosis of Guillain Barré syndrome. In order to evaluate the clinical characteristics and evolution of this disorder we reviewed the clinical records of patients admitted with this diagnosis to our Hospital between January 1987 and December 1996. We identified 44 patients with respiratory failure. The age was 34.0 +/- 14.1 years, 31 patients were male and 13 female; 70.5% required mechanical ventilation (MV). The time elapsed between the beginning of symptoms and MV was 9.4 +/- 8.0 days. Total duration of MV was 1,224 +/- 1,208 hours. Patients who required ventilatory support during the first 48 hours of evolution had a significantly longer duration of MV compared to the rest of the group (2,100 +/- 2,076 vs 934 +/- 735 hours, p < 0.05). Two of the survivors needed ventilatory support for more than 6 months. All patients showed quadriparesia, 55% had cranial nerve involvement and 43% had autonomic dysregulation. Twenty-four percent had a positive serologic titer for cytomegalovirus infection. The vital capacity measured before the beginning of MV was 1,050 +/- 378 ml and at discharge 2,837 +/- 1,080 ml. Mortality was 18%, with a higher mean age among those who died (44.9 +/- 17.5 years vs 31.9 +/- 12.5, p < 0.02). Mortality was also related to sepsis, barotrauma and severe autonomic dysfunction. In our group, we identified male preponderance, a high percentage of MV with an extended duration, and a longer MV time in the group of patients with a faster evolution.

Prolongation of epidural anaesthesia in dogs with bupivacaine in a lipid emulsion

An aqueous solution and a lipid emulsion of bupivacaine were administered epidurally in doses of 1.8 mg/kg to six beagle dogs following a randomised two-phase crossover design. The aqueous solution was absorbed rapidly and the mean (sd) peak venous plasma concentration of bupivacaine, 1.4 (0.4) microg/ml, was detected after five minutes. After administration of the lipid emulsion, the peak plasma concentration of bupivacaine, 0.6 (0.2) microg/ml, was detected after 30 minutes. The mean (sd) t1/2beta of the aqueous preparation was 149.1 (32.6) minutes, and of the lipid emulsion 119.2 (34.0) minutes. Both preparations had a similar bioavailability. The mean time to the onset of motor block after the administration of the aqueous solution, 2.3 (2.2) minutes, was significantly shorter (P=0.028) than after the administration of the lipid emulsion, 9.4 (1.9) minutes, and the duration of the motor block induced by the lipid emulsion, 217.6 (26.2) minutes, was significantly longer (P=0.043) than for the aqueous solution, 158 (48.8) minutes. During anaesthesia, the plasma concentrations of bupivacaine ranged between 1.3 and 0.2 microg/ml. Non-significant changes in systolic blood pressure and heart rate were observed which coincided with the peak plasma concentrations of bupivacaine.

Taenia crassiceps cysticercosis: protective effect and immune response elicited by DNA immunization

The nucleotide sequence of a protective recombinant antigen of Taenia crassiceps cysticerci present in all stages of Taenia solium (KETc7), cloned into pcDNA3 plasmid with the signal peptide sequence of the beta-glycan receptor (pTc-sp7), has been shown to be effective in protecting mice against experimental infection of T. crassiceps. To explore further the possibilities of this form of immunization and the immune response induced, mice were injected intramuscularly (i.m.) or intradermally (i.d.) with 3 doses of pTc-sp7. Similar levels of resistance were found using either i.m. or i.d. immunization. Spleen cells from i.d. and i.m. DNA immunized mice induced a specific T-cell response to T. crassiceps antigens and to a synthetic peptide from the immunogen itself (GK-1). Proliferated cells were especially enriched in CD8+ CD4- T-lymphocytes. A clear increase in the percentage of CD3+ cells that produce gamma-interferon and interleukin-2 was detected when measuring the intracellular cytokine production, an indication of the pTc-sp7 capacity to induce an effective cellular response. These results provide encouraging information on the use of KETc7 in the prevention of cysticercosis as well as a first insight into the characterization of the immune response induced by pTc-sp7 that hints to the relevance of cellular immunity in protection.

[Fulminant streptococcus infection of soft tissue]

BACKGROUND

In recent years there has been an apparent increase in severe infections produced by group A beta-hemolytic Streptococci in developed countries. Necrotizing fascitis and myositis are two rare but fearsome complications caused by this microorganism.

METHODS

Two cases of fulminant soft tissue infection recently observed in the authors' center are presented and the clinical presentation and differential diagnosis commented upon.

RESULTS

The first case was a necrotizing fascitis at a surgical wound which appeared following a gynecological surgery. The second case reports gluteal myositis following intramuscular injection. In both cases the evolution was disastrous.

CONCLUSIONS

Streptococcus pyogenes may produce fulminant infections in patients without underlying disease either spontaneously or following minimum traumas. The most frequent involvement is of the soft tissues. This virulence at a local tissue and systemic level has been associated with the production of exotoxin.

[Dose-effect of the administration of ferrous fumarate in aged persons with iron deficiency]

BACKGROUND

Anemia is the most prevalent hematological problem in elderly persons, affecting 14% of the males and 6% of the females of the population over 60 years of age in Mexico City.

OBJECTIVE

To determine the effect produced by the prolonged administration of ferrous fumarate in elderly persons with iron deficiency.

METHOD

In a population of 178 subjects, aged between 65 to 100 years, iron deficiency was diagnosed in 51 (28.6%), who had serum iron concentrations below 80 micrograms/dL for men and 60 micrograms/dL for women, but only 21 patients (11.8%), accepted to participated in the study. The response to a 6 months oral administration of ferrous fumarate were studied with a daily oral dose of 5 mg/kg of elemental iron. The patients were classified in 3 groups according to the abnormal parameters of iron metabolism (group 1 = 10.9% anemia, group 2 = 28.0% and group 3 = 63.0% anemia).

RESULTS

The efficacy of treatment was evaluated by quantification of the changes occurred in serum iron concentrations, hemoglobin, ferritin and transferrin saturation index, at 0, 30, 90 and 180 days of treatment. This study showed that the treatment of oral ferrous fumarate in elderly patients with iron deficiency, produces a quantifiable improvement in measures of iron parameters within 6 months.

CONCLUSIONS

The results of this study suggest the usefulness of prolonged treatment with ferrous fumarate in elderly patients with iron deficiency, to avoid therapeutic failure as a consequence of non-compliance as is common in elderly patients.

Pharmacokinetics and pharmacologic effects of the S(-) isomer of bupivacaine after intravenous and epidural administration in dogs

OBJECTIVE

To determine pharmacokinetic variables and pharmacologic effects of the S(-) isomer of bupivacaine (S[-]-BPV) in dogs.

ANIMALS

6 adult male Beagles.

PROCEDURE

Dogs received S(-)-BPV (1 mg/kg of body weight) i.v., and 15 days later, the same dogs received 1.8 mg/kg epidurally. Pharmacokinetic variables and pharmacologic effects were determined for each route of administration.

RESULTS

After i.v. administration, plasma concentration versus time curves were adjusted, using biexponential equations that indicated a rapid distribution phase followed by a slower elimination phase, with a mean +/- SD half-life of 33.5 +/- 17.0 minutes. Mean plasma clearance was 21.0 +/- 10.7 ml/min/kg, and mean volume of distribution at steady state was 0.8 +/- 0.2 L/kg. After i.v. administration, mean peak plasma concentration was 2.6 +/- 0.7 micrograms/ml; after epidural administration, it was 0.9 +/- 0.5 microgram/ml at approximately 3 minutes. Half-life after epidural administration was 5 times longer than that observed after i.v. administration. Motor block began immediately after the end of epidural administration and lasted for 3 to 4 hours. Changes in systolic blood pressure and heart rate after epidural administration were slight but occurred at the same time that plasma concentration peaked. After i.v. administration, motor block or variations in physiologic variables studied were not observed.

CONCLUSIONS AND CLINICAL RELEVANCE

In dogs, the pharmacologic behavior of S(-)-BPV was similar to that of the bupivacaine racemate, but motor block attributable to S(-)-BPV lasted longer than that attributable to the racemate, with lower plasma concentrations observed at equivalent sample collection times.

Towards a Taenia solium cysticercosis vaccine: an epitope shared by Taenia crassiceps and Taenia solium protects mice against experimental cysticercosis

The Taenia crassiceps recombinant antigen KETc7 has been shown to be effective as a vaccine against experimental murine cysticercosis, a laboratory model used to test potentially promising molecules against porcine Taenia solium cysticercosis. Based on the deduced amino acid sequence of this proline-rich polypeptide, three fragments, GK-1, GK-2, and GK-3, were chemically synthesized in linear form. Of the three peptides, only GK-1 induced sterile protection against T. crassiceps cysticercosis in 40 to 70% of BALB/cAnN male mice. GK-1 is an 18-amino-acid peptide which contains at least one B-cell epitope, as demonstrated by its ability to induce an antibody response to the peptide and T. crassiceps antigen without need of a carrier protein. Immunofluorescence studies revealed that anti-GK1 antibodies strongly react with the native protein in the tegument of T. crassiceps and also with anatomical structures of T. solium eggs, oncospheres, cysticercus, and tapeworm. GK-1 also contains at least one T-cell epitope, capable of stimulating the proliferation of CD8(+) and to a lower extent CD4(+) T cells primed either with the free peptide or T. crassiceps total antigen. The supernatant of the stimulated cells contained high levels of gamma interferon and low levels of interleukin-4. Similar results were obtained with T cells tested for intracellular cytokine production, an indication of the peptide's capacity to induce an inflammatory response. The remarkable protection induced by GK-1 immunization, its physicochemical properties, and its presence in all developmental stages of T. solium point to this synthetic peptide as a strong candidate in the construction of a synthetic vaccine against T. solium pig cysticercosis.

Chemical composition, digestibility and antinutritional factors content of two wild legumes: Styphonolobium burseroides and Acacia bilimekii

The chemical composition, digestibility and toxin contents of two wild legumes: Styphnolobium burseroides and Acacia bilimekii, collected in a semi-arid zone of Mexico, were determined. Both legumes had a high fiber content. The seeds of Styphnolobium burseroides had a low protein content (14%), and the pod a high content of reducing sugars. However the seeds of Acacia bilimekii had a high protein concentration (35%). The seed proteins were low in sulphur amino acids and tryptophan in both legumes but were rich in lysine. Trypsin inhibitors and lectins were present in low concentrations; alkaloids and cyanogenic glucosides were not detected. The in vitro digestibility for monogastric animals was low but the same test with ruminal juice showed a high digestibility for both legumes. Based on their chemical composition and digestibility, these legumes could be a good alternative source in the feeding of ruminants.

Reduction of laparoscopic-induced hypothermia, postoperative pain and recovery room length of stay by pre-conditioning gas with the Insuflow device: a prospective randomized controlled multi-center study

OBJECTIVE

To assess the efficacy and safety of Insuflow (Georgia BioMedical, Inc.) filter heater hydrator device in reducing the incidence, severity and extent of hypothermia, length of recovery room stay and postoperative pain at the time of laparoscopy.

DESIGN

Prospective, randomized, blinded, controlled multi-center study. Patients underwent gynecologic procedures via laparoscopy; surgeons, anesthesiologists and recovery room personnel assessed the results.

SETTING

Seven North American institutions.

PATIENTS

Seventy-two women for safety evaluation and efficacy studies.

INTERVENTIONS

Intraoperative pre-conditioning of laparoscopic gas with the Insuflow device (treatment) or standard raw gas (control) during laparoscopic surgery and postoperatively.

MAIN OUTCOME MEASURES

Incidence, severity and extent of hypothermia, postoperative pain perception and length of recovery room stay.

RESULTS

The Insuflow group had significantly less intraoperative hypothermia, reduced length of recovery room stay and reduced postoperative pain. Pre-conditioning of laparoscopic gas by filtering heating and hydrating was well tolerated with no adverse effects. The safety profile of the Insuflow pre-conditioned gas showed significant benefits compared to currently used raw gas.

CONCLUSIONS

Pre-conditioning laparoscopic gas by filtering heating and hydrating with the Insuflow device was significantly more effective than the currently used standard raw gas and was safe in reducing or eliminating laparoscopic-induced hypothermia, shortening recovery room length of stay and reducing postoperative pain.

In vitro culture of Taenia crassiceps larval cells and cyst regeneration after injection into mice

Taenia crassiceps cysticerci were disrupted through trypsinization to isolate cells which can be maintained in culture for up to 15 days. When injected intraperitoneally into susceptible BALB/cAnN mice, complete cysticerci were recovered in a number that is proportional to the quantity of injected cells. Thus, cysticerci contain cells which can reconstitute complete cysts, suggesting that individual cells play a role, independent to budding, during asexual multiplication of T. crassiceps cysticerci in the peritoneal cavity of mice. In contrast, injection of the cells into resistant C57BL/6J mice does not result in the recovery of complete cysts. These findings provide a new experimental model to identify resistance factors in the hosts, for the in vitro screening of anti-cysticerci drugs and for the genetic manipulation of cysticerci through recombinant DNA techniques.

Bupivacaine disposition and pharmacologic effects after intravenous and epidural administrations in dogs

Pharmacokinetic variables of bupivacaine (BPV) were determined after IV and epidural administrations in the same 6 dogs. Plasma BPV concentration curves after IV administration were adjusted to biexponential kinetics: a rapid distribution phase was followed by a slower elimination phase, with half-life of 34.5 +/- 7.8 minutes. Mean plasma clearance was 20.2 +/- 7.4 ml/min/kg of body weight, and mean volume of distribution at steady state was 0.7 +/- 0.2 L/kg. After epidural administration, absorption was rapid. Peak plasma concentration, 1.4 +/- 0.4 microgram/ml, was detected approximately 5 minutes after BPV administration. The half-life corresponding to epidural administration (179 +/- 33.6 minutes) was 5 to 6 times longer than that observed after IV administration, possibly because of the slow release of BPV from the epidural space. Induction times were short (2.3 +/- 2.2 minutes); anesthesia quickly began and lasted for more than 2 hours (158 +/- 48.8 minutes). During that period, BPV plasma concentration ranged between 1.4 and 0.2 microgram/ml. Changes in systolic blood pressure and heart rate were correlated to high plasma concentration of BPV. These modifications were observed for the first 30 minutes, reaching baseline values after 60 minutes.