Genetic Variability in the E6/E7 Region of Human Papillomavirus 16 in Women from Ecuador

Human Papillomavirus (HPV) infection is associated with intraepithelial neoplasia and cervical cancer (CC). Ecuador has a high prevalence of cervical cancer, with more than 1600 new cases diagnosed annually. This study aimed to analyze oncogenes E6 and E7 of HPV16 in samples collected from women with cancerous and precancerous cervical lesions from the Ecuadorian coast. Twenty-nine women, including six with ASCUS, three with LSIL, thirteen with HSIL, and seven with Cacu, were analyzed. The most common SNPs were E6 350G or L83V (82.6%) and E6 145T/286A/289G/335T/350G or Q14H/F78Y/L83V (17.4%). Both variants are reported to be associated with an increased risk of cervical cancer in worldwide studies. In contrast, all E7 genes have conserved amino-acid positions. Phylogenetic trees showed the circulation of the D (26.1%) and A (73.9) lineages. The frequency of D was higher than that reported in other comparable studies in Ecuador and Latin America, and may be related to the ethnic composition of the studied populations. This study contributes to the characterization of the potential risk factors for cervical carcinogenesis associated with Ecuadorian women infected with HPV16.

Genetic regulation of the ompX porin of Salmonella Typhimurium in response to hydrogen peroxide stress

Background

Salmonella Typhimurium is a Gram-negative pathogen that causes a systemic disease in mice resembling typhoid fever. During its infective cycle, S. Typhimurium is phagocytized by macrophages and proliferates inside a Salmonella-containing vacuole where Salmonella is exposed and survives oxidative stress induced by H₂O₂ through modulation of gene expression. After exposure of Salmonella to H₂O₂, the expression of the porin-encoding gene ompX increases, as previously shown by microarray analysis. Expression of ompX mRNA is regulated at a post-transcriptional level by MicA and CyaR sRNAs in aerobiosis. In addition, sequence analysis predicts a site for OxyS sRNA in ompX mRNA.

Results

In this work we sought to evaluate the transcriptional and post-transcriptional regulation of ompX under H₂O₂ stress. We demonstrate that ompX expression is induced at the transcriptional level in S. Typhimurium under such conditions. Unexpectedly, an increase in ompX gene transcript and promoter activity after challenges with H₂O₂ does not translate into increased protein levels in the wild-type strain, suggesting that ompX mRNA is also regulated at a post-transcriptional level, at least under oxidative stress. In silico gene sequence analysis predicted that sRNAs CyaR, MicA, and OxyS could regulate ompX mRNA levels. Using rifampicin to inhibit mRNA expression, we show that the sRNAs (MicA, CyaR and OxyS) and the sRNA:mRNA chaperone Hfq positively modulate ompX mRNA levels under H₂O₂-induced stress in Salmonella during the exponential growth phase in Lennox broth.

Conclusions

Our results demonstrate that ompX mRNA is regulated in response to H₂O₂ by the sRNAs CyaR, MicA and OxyS is Salmonella Typhimurium.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40659-022-00377-3.

Political partisanship and mobility restriction during the COVID-19 pandemic

OBJECTIVES

Non-pharmaceutical interventions (NPIs) are effective in curbing the spread of severe acute respiratory syndrome coronavirus 2. All US states have adopted NPI policies, but the compliance to these measures and influence of sociopolitical factors on NPI adherence is unknown. NPI adherence may be approximated by personal mobility in a population that is tracked by anonymous mobile phone data.

STUDY DESIGN

This is a cross-sectional study of state-level mobility changes across the US.

METHODS

State-level mobility was based on anonymous mobile phone data from multiple participating carriers collected by the University of Washington's Institute for Health Metrics and Evaluation (http://www.healthdata.org). Pearson's correlation coefficient was used to examine the strength and direction of the relationship between political affiliations and mobility restriction across states. Multivariable linear regression analyses were used to assess other factors that may impact personal travel.

RESULTS

All states experienced a decline in personal mobility but had varying nadirs ranging from a 34% to a 69% reduction in mobility, which was not temporally related to the timing of state-level NPI measures. There was a statistically significant linear and negative correlation (r = -0.79) between the proportion of Republicans/leaning Republicans and NPI adherence across US states. The negative association between Republicans and NPI adherence was significant even when adjusting for urbanization, proportion of essential workers, population, Gini index, and poverty rates.

CONCLUSIONS

Political orientation affects risk perception, which may contribute to the unwillingness of some individuals to perceive the coronavirus disease 2019 pandemic as a risk and to comply with NPIs. Our results highlight the importance of sociopolitical factors in disease control and emphasize the importance of bipartisan efforts in fighting the pandemic. These results may have implications for the development, dissemination, and communication of public health policies.

The Latin American Biological Dosimetry Network (LBDNet)

Biological Dosimetry is a necessary support for national radiation protection programmes and emergency response schemes. The Latin American Biological Dosimetry Network (LBDNet) was formally founded in 2007 to provide early biological dosimetry assistance in case of radiation emergencies in the Latin American Region. Here are presented the main topics considered in the foundational document of the network, which comprise: mission, partners, concept of operation, including the mechanism to request support for biological dosimetry assistance in the region, and the network capabilities. The process for network activation and the role of the coordinating laboratory during biological dosimetry emergency response is also presented. This information is preceded by historical remarks on biological dosimetry cooperation in Latin America. A summary of the main experimental and practical results already obtained by the LBDNet is also included.

[Establishment of a preclinical neuroblastoma model in immunocompetent mice]

AIM

To develop a NB animal model which makes possible studies related to tumor immunity.

MATERIALS AND METHODS

Two types of NB cells were used. Cell line 36769 was derived from TH-MYCN+ mouse in which overexpression of the MYCN gene is governed by rat tyrosine hydroxylase promotor. Cell line 4040 was derived from TH-MYCN/ALK mice, which in addition express an activating mutation of ALK gene. For each cell type, 1x10⁶ neurospheres were implanted in 129/SVJ mice (with the same genetic background as donors, n=8), via orthotopic injection in the left suprarenal gland by intraperitoneal approach, through a transverse supraumbilical laparotomy. Daily postsurgical clinical follow-up of the animals was done until they were sacrificed at four weeks. The tumor presence was macroscopically confirmed. The tumoral sample was excised and was processed for cellular immunity and molecular tolerance mediator's studies. The existence of metastasis was investigated by flow cytometry in the spleen, bone marrow and peripheral blood.

RESULTS

1) Orthotopic Neuroblastoma was generated in all the transplanted mice. 2) The tumors were infiltrated by several immune subpopulations, with effector, regulatory and suppressor inmunophenotype. This was similar to the inmunophenotype described in human NB. Furthermore, the molecular mediators of the environment point to a state of protumoral tolerance.

CONCLUSION

The orthotopic implantation of NB neurospheres in syngeneic mice has allowed us to generate a NB model in which it has been possible to study the tumor immunity.

Interlaboratory comparison of dicentric chromosome assay using electronically transmitted images

The bottleneck in data acquisition during biological dosimetry based on a dicentric assay is the need to score dicentrics in a large number of lymphocytes. One way to increase the capacity of a given laboratory is to use the ability of skilled operators from other laboratories. This can be done using image analysis systems and distributing images all around the world. Two exercises were conducted to test the efficiency of such an approach involving 10 laboratories. During the first exercise (E1), the participant laboratories analysed the same images derived from cells exposed to 0.5 and 3 Gy; 100 images were sent to all participants for both doses. Whatever the dose, only about half of the cells were complete with well-spread metaphases suitable for analysis. A coefficient of variation (CV) on the standard deviation of ∼15 % was obtained for both doses. The trueness was better for 3 Gy (0.6 %) than for 0.5 Gy (37.8 %). The number of estimated doses classified as satisfactory according to the z-score was 3 at 0.5 Gy and 8 at 3 Gy for 10 dose estimations. In the second exercise, an emergency situation was tested, each laboratory was required to score a different set of 50 images in 2 d extracted from 500 downloaded images derived from cells exposed to 0.5 Gy. Then the remaining 450 images had to be scored within a week. Using 50 different images, the CV on the estimated doses (79.2 %) was not as good as in E1, probably associated to a lower number of cells analysed (50 vs. 100) or from the fact that laboratories analysed a different set of images. The trueness for the dose was better after scoring 500 cells (22.5 %) than after 50 cells (26.8 %). For the 10 dose estimations, the number of doses classified as satisfactory according to the z-score was 9, for both 50 and 500 cells. Overall, the results obtained support the feasibility of networking using electronically transmitted images. However, before its implementation some issues should be elucidated, such as the number and resolution of the images to be sent, and the harmonisation of the scoring criteria. Additionally, a global website able to be used for the different regional networks, like Share Points, will be desirable to facilitate worldwide communication.

Diet composition and diel feeding behaviour of the banded guitarfish Zapteryx xyster along the Pacific coast of Costa Rica, Central America

The diet and diel feeding behaviour of the banded guitarfish Zapteryx xyster were examined along the Pacific coast of Costa Rica. A sample of 235 stomachs was collected between March 2010 and December 2011 as part of an ongoing shrimp-trawl by-catch monitoring programme. Samples from multiple day and night periods allowed testing the hypothesis that Z. xyster is more active at night, thus increasing the amount of food intake during night-time. Overall, shrimps (52·3% prey-specific index of relative importance, P(SIRIi) ) and teleosts (27·2% P(SIRIi) ) were the most important prey categories. Juveniles fed primarily on smaller shrimps (Solenocera spp.), while adults shifted to larger prey. The amount of food consumed (as % of bodymass) by juvenile and adult Z. xyster increased significantly between 0400 and 1200 hours, while the proportion of empty stomachs decreased during the same time interval. These findings contradict the hypothesis that Z. xyster is more active and feeds at night. The study also revealed that Z. xyster, particularly juveniles, forage on several shrimp species and overlap spatially with the Costa Rican bottom-trawl fisheries. This has important management and conservation implications as Z. xyster may be experiencing high by-catch rates, and because of their life history is presumed to be vulnerable to intense levels of exploitation.

Ontogenetic dietary shifts and feeding ecology of the rasptail skate Raja velezi and the brown smoothhound shark Mustelus henlei along the Pacific coast of Costa Rica, Central America

Stomachs from 511 Raja velezi and 340 Mustelus henlei captured as by-catch in the commercial trawling fishery (2010-2012) were analysed to examine diet composition, ontogenetic shifts and degree of dietary overlap between species life stages in the Pacific Ocean of Costa Rica. Shrimps were the most important prey categories in the diet of R. velezi, while teleosts and cephalopods dominated the diet of M. henlei. Diet comparisons between different stages of R. velezi and M. henlei revealed clear ontogenetic dietary shifts: crustaceans (mainly shrimps, crabs and stomatopods) dominated the diet of immature individuals, and adults had a higher proportion of teleosts. The results suggest that R. velezi is an epibenthic predator that specializes in shrimps during early life stages, and to a lesser extent, teleosts as it matures, while M. henlei is an opportunistic predator with a highly diverse diet consisting of teleosts, cephalopods, shrimps and stomatopods. This study also found little evidence of dietary overlap between species or life stages and suggests that intra- and interspecific competition between R. velezi and M. henlei may be reduced by: (1) diet specialization in immature stages of R. velezi, (2) ontogenetic dietary shifts between immature and mature individuals, (3) prey-size selectivity in larger individuals of R. velezi and (4) differences in depth utilization in overlapping geographical regions.

[Pro-hepcidin, its relation with indicators of iron metabolism and of inflammation in patients hemodialyzed treated or not with recombinant erythropoietin]

Hepcidin, an antimicrobial peptide which synthesis is regulated by iron status and inflammation, plays an important role in iron homeostasis in hemodialysed (HD) patients. It is measured by measuring serum prohepcidin.

OBJECTIVE

To determine serum prohepcidin levels and their relationship with serum ferritin, C reactive protein (CRP), and albumin in HD patients treated or not with recombinant erythropoietin (EPO) that attended the Health Centre of the Carabobo State in Venezuela.

METHODOLOGY

This is a descriptive, correlational, and field investigation with a sample comprised by 71 HD patients of whom 57 were treated with EPO. Serum prohepcidin, ferritin, haemoglobin, hematocrit, CRP, and albumin were determined. Anaemia (haemoglobin < 10 g/dL) and iron deficiency (ferritin < 100 ng/mL) were defined according to the criteria recommended by the K/DOQUI group. Reference values: Albumin 3.5-4.8 g/dL, and for acute inflammatory conditions (CRP > 10 mg/L.).

RESULTS

The mean value for prohepcidin was 397.5 ng/mL. A high percentage of anaemia was observed (87.3%) and 22.5% of the patients had low levels of serum ferritin. There were no statistically significant differences for ferritin, albumin, CRP, or prohepcidin, between patients with and without EPO therapy. Only the CRP value was significantly correlated (rho = 0.276; p = 0.020) with prohepcidin.

CONCLUSION

HD patients present high levels of prohepcidin, and this may be due to the common ongoing inflammatory process in these patients and not to the iron status measured through serum ferritin levels.

Effectiveness and cost of replacing a calcineurin inhibitor with sirolimus to slow the course of chronic kidney disease in renal allografts

Renal grafts suffer a progressive decrease in glomerular filtration rate (GFR) because of several factors including calcineurin inhibitor (CNI) nephrotoxicity. Switching CNIs to sirolimus may improve this adverse prognosis. We performed a prospective, open-label clinical trial among 18 kidney transplant patients with more than 12 months of evolution (range, 385-1826 days), showing progressive GFR decreases and biopsies with interstitial fibrosis and tubular atrophy (IFTA). Immunosuppressive treatment included cyclosporine, ketoconazole, and steroids associated with azathioprine or mycophenolate mofetil. After signing an Institutional Review Board-approved written consent, cyclosporine was switched to sirolimus seeking to achieve a trough blood sirolimus concentration of 6-15 ng/mL. Wilcoxon and Student's t-tests were used to compare the values in the annual periods before and after the switch. GFR was estimated by the Modification of Diet in Renal Disease formula. There were no acute rejection episodes. Estimated GFR on the day of the switch was 38.0 +/- 12.1 mL/min. After CNI switch, the slope of the estimated GFR significantly improved from -6.5 +/- 9.2 to 8.1 +/- 14.0 mL/min/year (P < .01). The estimated GFR 1 year after the switch was 47.2 +/- 16.9 mL/min (P = .003 vs baseline). Total expenditures increased. The ratio of post-switch versus baseline total expenditures was 1.93 (95% confidence interval, 1.54-2.31) and the ratio of sirolimus to CNI cost was 2.16 (95% confidence interval, 1.53-2.78). Switching from CNI to sirolimus for kidney transplants with decreasing GFR and a biopsy with IFTA changes, suggesting progressive graft nephropathy, almost doubled total expenses. It is necessary to conduct trials using clinical end points to definitively validate this therapeutic intervention.

Everolimus versus azathioprine in a cyclosporine and ketoconazole-based immunosuppressive therapy in kidney transplant: 3-year follow-up of an open-label, prospective, cohort, comparative clinical trial

In cyclosporine-based protocols, everolimus is more effective than azathioprine to reduce acute rejection. Ketoconazole may reduce cyclosporine and everolimus requirements. We compared kidney transplant patients treated with everolimus or azathioprine in a ketoconazole- and cyclosporine-based immunosuppressive regimen. This open-label, prospective trial of low immunologic risk patients. Included one group (n = 11) who received everolimus (target blood level, 3-8 ng/mL) and the other (n = 11) azathioprine (2.0-2.5 mg/kg/d). Both received steroids, ketoconazole, and cyclosporine with C(0) targets (ng/mL) in the everolimus group of 200-250, 100-125, and 50-65 for months 1 and 2 and thereafter and in the azathioprine group of 250-300 in month 1, 200-250 in month 2, 180-200 until month 6, and 100-125 thereafter. Their baseline characteristics were similar. Two biopsy-proven acute rejections occurred in each group. Three-year graft and patient survival in both groups was 100%. Creatinine clearances at months 6, 12, 24, and 36 were 63.7 +/- 25.4, 58.9 +/- 24.9, 56.0 +/- 22.9, and 57.0 +/- 27.6 in the everolimus group versus 72.6 +/- 20, 68.6 +/- 21.3, 71.4 +/- 23.2, and 68.4 +/- 19.2 in the azathioprine group (NS for every comparison). Major complications were rare and similar in both groups. Five patients in the everolimus group received simvastatin versus 4 in the azathioprine cohort (P = .53). The average cyclosporine doses to achieve targets were 0.8-1.2 mg/kg in the everolimus group and 1.6-2.2 mg/kg in the azathioprine group. The average everolimus dose after month 2 was 0.75-0.9 mg/d. We concluded that with cyclosporine, ketoconazole, and steroids, everolimus was as effective and safe as azathioprine. Cyclosporine reduction with everolimus did not influence graft survival or function at 3 years.

[Pumpless extracorporeal pulmonary care: an alternative in the treatment of persistent acute respiratory distress syndrome]

A 34-year old woman who developed persistent and severe acute respiratory distress syndrome with underlying myelomonocytic leukemia (M4FAB) is described. After ruling out the most common causes of pulmonary infiltration in this type of patient and one week of broad spectrum antibiotics and steroids therapy, we proposed leukemic pulmonary infiltration as etiological diagnosis. Despite using a protective ventilatory strategy, recruitment maneuvers, prone position and high frequency oscillatory ventilation, her gas exchange became worse. Under this condition we used a Pumpless-Extracorporeal life assist (PELA) and begun chemotherapy. The method, arterial blood gases, hemodynamic parameters and ventilatory mechanics before and after its use are described. The patient remained on P-ELA for nine days; one week later she was extubated and ten days after she was discharged from the Intensive Care Unit the patient left the hospital in good health condition.

Population genetic data for 18 STR loci in Costa Rica

Allele frequencies for 18 STR autosomal loci (D3S1358, VWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820, D16S539, TH01, TPOX, CSF1PO, Penta D, Penta E, D19S433, D2S1338 and SE33) were obtained from a sample of 191-500 unrelated individuals from Costa Rica, Central America.

An adaptive input-output modeling approach for predicting the glycemia of critically ill patients

In this paper we apply system identification techniques in order to build a model suitable for the prediction of glycemia levels of critically ill patients admitted to the intensive care unit. These patients typically show increased glycemia levels, and it has been shown that glycemia control by means of insulin therapy significantly reduces morbidity and mortality. Based on a real-life dataset from 15 critically ill patients, an initial input-output model is estimated which captures the insulin effect on glycemia under different settings. To incorporate patient-specific features, an adaptive modeling strategy is also proposed in which the model is re-estimated at each time step (i.e., every hour). Both one-hour-ahead predictions and four-hours-ahead simulations are executed. The optimized adaptive modeling technique outperforms the general initial model. To avoid data selection bias, 500 permutations, in which the patients are randomly selected, are considered. The results are satisfactory both in terms of forecasting ability and in the clinical interpretation of the estimated coefficients.

Cyclosporine-Associated Leukoencephalopathy in Organ Transplant Recipients: Experience of Three Clinical Cases

Leukoencephalopathy is a structural alteration of cerebral white matter mainly involving damage to myelin. Several reports have linked cyclosporine (CsA) with this alteration. The clinical features vary from qualitative alterations of consciousness to neurological deficits. Magnetic resonance imaging (MRI) of the brain demonstrates the damage to the white matter, which is essential for the differential diagnosis. We describe three clinical cases of leukoencephalopathy. The first case is a 43-year-old man received a cadaveric kidney transplant using immunosuppression with of mycophenolate mofetil, prednisone, and CsA. Four months later he developed meningism and bilateral sixth nerve palsy. The second case is a 50-year-old man with a cadaveric kidney transplant received immunosuppressive treatment with azathioprine and prednisone. As a result of gouty arthritis of the ankle, azathioprine was replaced with CsA to allow addition of allopurinol. Two weeks later he developed confusion and personality changes. The third case is a 16-year-old man received a orthotopic liver transplant. Postoperatively he suffered generalized tonic-clonic seizures. In all patients the CsA levels were toxic and signs of neurological alterations were present on MRI. All patients recovered rapidly after CsA withdrawal.

STR data for 11 autosomal STR markers from Costa Rica, Central America

Allele frequencies for 11 STR autosomal loci (F13A01, F13B, FESFPS, LPL, CSF1PO, TH01, TPOX, VWA, D16S539, D7S820 and D13S317) were obtained from a sample of 200 unrelated individuals from Costa Rica, Central America.

Impact of Pregnancy on the Function of Transplanted Kidneys

INTRODUCTION

This study reviewed the course of pregnancies in terms of impact on renal function and delivery-related data among women who received kidney transplants in our unit.

METHODS

We reviewed the medical records of women transplanted between 1982 and 2002 who became pregnant. We recorded the data of medical, obstetrical, and transplant-related complications, plasma creatinine levels, and blood pressures at baseline, delivery, and 12 months after delivery.

RESULTS

Thirty women had 37 pregnancies. Immunosuppressive protocols included cyclosporine, ketoconazole, azathioprine, and prednisone in 22 patients or azathioprine and prednisone in 15. Renal function decreased significantly: mean creatinine levels at baseline, delivery, and after 1 year were: 1.19 +/- 0.38 mg/dL; 1.44 +/- 0.70 mg/dL; and 1.38 +/- 0.53 mg/dL, respectively (P = .023 and P = .004 vs baseline respectively). Systolic and diastolic blood pressures at delivery were higher than at baseline (134 +/- 19 and 86 +/- 14 mm Hg vs 126 +/- 21 and 79 +/- 13 mm Hg (P = .029 and P = .053, respectively). These values normalized 1 year later (128 +/- 21 and 80 +/- 16). Decreased use of antihypertensive drugs were the cause of poor blood pressure control (1.8 +/- 1.3 vs 0.9 +/- 0.7, P < .01). Blood pressure control improved following delivery. The most frequent complications were preeclampsia (18.9%), intrahepatic cholestasis (13.5%), and urinary tract infections (13.5%). There were five rejection episodes. Seven miscarriages took place and one mole. Eleven pregnancies were uncomplicated.

CONCLUSION

Renal transplantation is the best treatment for fertile women with end-stage renal disease who want to become pregnant. However, pregnancy is risky for the mother, fetus, newborn, and allograft.

[Reference values of growth hormone binding protein (GHBP) for a normal pediatric population]

Circulating concentrations of the high affinity growth hormone binding protein (GHBP) may be a marker of GH receptor density as well as GH sensitivity.

GOAL

To determine values of GHBP for a normal Chilean pediatric population.

METHODS

We determined GHBP levels in 73 males and 73 females between 4 to 15.5 years and 4 to 16.8 years respectively, divided in 7 groups according to age and puberal status.

RESULTS

The population was normally distributed in weight, height and body mass index (BMI). GHBP activity increased up to Tanner IV in males and Tanner III in females, and decreased slightly thereafter in Tanner V and IV respectively. There was a significant difference between GHBP levels of preschool children and those found in Tanner II to V in both sexes (p < 0.05). In addition, we found a positive correlation between GHBP vs weight, height and BMI (p < 0.001) in males and females.

CONCLUSION

The availability of this methodology allows us to establish the normative value of GHBP in our population and provides useful information to interpret GH circulating levels in children with growth disorders.

Omental transplantation for Alzheimer's disease

The acetylcholine, dopamine, serotonin and other neurotransmitters may be reduced in the subcommissural regions even in the early stages of Alzheimer's disease(AD), due to hypoperfusion of the anterior perforating and anterior choroidal arteries. This hypothesis was confirmed after the transplant of omental tissue on the optic chiasma, carotid crotch and anterior perforated space in a woman with moderate AD. Neurological improvement was better in the first week after the surgery than in the following months.

Conformational change as one of the earliest alterations of tau in Alzheimer's disease

Paired helical filaments (PHFs) found in Alzheimer's disease (AD) are mainly comprised of an abnormal form of tau (PHF-tau) that has undergone several post-translational modifications. Previous studies have shown that the monoclonal antibody MCI identifies a distinct conformation of tau in AD. We have assessed the temporal and spatial occurrence of the tau conformation recognized by MC1, and found its appearance in hippocampal neurons vulnerable to neurofibrillary tangle (NFT) formation in Braak Stage I and II cases. Electron microscopy has clearly demonstrated that this conformation precedes the formation of PHF. MC1 immunoaffinity chromatography also has identified a nonfilamentous, soluble pool of this abnormal tau. ELISA and immunoblotting have shown that this material is indistinguishable from that found in NFTs. This soluble component has the ability to self-assemble into PHFs in a concentration-dependent manner. Because the conformational change recognized by MCI appears before the assembly of and is found in PHF, but is not present in the normal brain, we suggest that the formation of the MCI epitope is one of the earliest pathological alterations of tau in AD.

Tumor necrosis factor alpha as a uremic toxin: correlation with neuropathy, left ventricular hypertrophy, anemia, and hypertriglyceridemia in peritoneal dialysis patients

Tumor necrosis factor alpha (TNF alpha) is usually excreted by the kidney. In dialysis patients, it accumulates. TNF alpha has been implicated in the pathogenesis of malnutrition, diabetic neuropathy, and erythropoietin resistance. We studied TNF alpha plasma levels in 49 stable peritoneal dialysis (PD) patients, with the aim of correlating those levels with the presence and severity of peripheral neuropathy, hypertrophic cardiomyopathy, and anemia. Kt/Vurea' residual renal creatinine clearance (CrC), nutritional markers, and general biochemistry were also determined. The average plasma level of TNF alpha was 67 +/- 32 pg/mL (range: 18.1-156.3 pg/mL; normal value 3-20 pg/mL). No correlation was observed between TNF alpha and KT/Vurea' but a negative correlation with CrC was seen (r: -0.37, p < 0.05). TNF alpha levels were higher in patients with neuropathy as compared to patients with normal results (72.5 +/- 32 pg/mL vs 44 +/- 22 pg/mL, p < 0.05). Patients with neuropathy also showed a lower CrC value (1.5 +/- 1.7 mL/min vs 3.9 +/- 2.6 mL/min, p < 0.01). TNF alpha levels were higher in patients with left ventricular hypertrophy (LVH) with respect to normal individuals (70.4 +/- 32 pg/mL vs 38.5 +/- 20.8 pg/mL, p < 0.05). Patients with severe LVH showed the lowest CrC value. A direct, significant relationship was found between TNF alpha levels and weekly erythropoietin dose (r: 0.41, p < 0.05). Patients with hypertriglyceridemia or taking lipid-lowering agents showed a positive linear correlation between TNF alpha and triglycerides (r = 0.7, n = 14, p < 0.05). These data suggest that accumulation of TNF alpha may contribute to the development or maintenance of some neurologic, hematologic, and cardiac complications of uremic syndrome. Loss of residual renal function conditions an increment in TNF alpha levels. These data continue to add support to the idea that TNF alpha may be considered a uremic toxin.

Macrophage migration inhibitory factor release by macrophages after ingestion of Plasmodium chabaudi-infected erythrocytes: possible role in the pathogenesis of malarial anemia

Human falciparum malaria, caused by Plasmodium falciparum infection, results in 1 to 2 million deaths per year, mostly children under the age of 5 years. The two main causes of death are severe anemia and cerebral malaria. Malarial anemia is characterized by parasite red blood cell (RBC) destruction and suppression of erythropoiesis (the mechanism of which is unknown) in the presence of a robust host erythropoietin response. The production of a host-derived erythropoiesis inhibitor in response to parasite products has been implicated in the pathogenesis of malarial anemia. The identity of this putative host factor is unknown, but antibody neutralization studies have ruled out interleukin-1beta, tumor necrosis factor alpha, and gamma interferon while injection of interleukin-12 protects susceptible mice against lethal P. chabaudi infection. In this study, we report that ingestion of P. chabaudi-infected erythrocytes or malarial pigment (hemozoin) induces the release of macrophage migration inhibitory factor (MIF) from macrophages. MIF, a proinflammatory mediator and counter-regulator of glucocorticoid action, inhibits erythroid (BFU-E), multipotential (CFU-GEMM), and granulocyte-macrophage (CFU-GM) progenitor-derived colony formation. MIF was detected in the sera of P. chabaudi-infected BALB/c mice, and circulating levels correlated with disease severity. Liver MIF immunoreactivity increased concomitant with extensive pigment and parasitized RBC deposition. Finally, MIF was elevated three- to fourfold in the spleen and bone marrow of P. chabaudi-infected mice with active disease, as compared to early disease, or of uninfected controls. In summary, the present results suggest that MIF may be a host-derived factor involved in the pathophysiology of malaria anemia.

[Usefulness of the measurement of insulin-like growth factor (IGF-I) and IGF-1 binding protein-3 (IGFBP-3) for the diagnosis of growth hormone (GH) deficiency in children]

BACKGROUND

The diagnosis of GH deficiency (GHD) is based upon the results of GH stimulation tests, which have several drawbacks.

AIM

To evaluate the usefulness of IGF-1 and IGFBP-3 for the diagnosis of GHD in prepuberal children.

MATERIAL AND METHODS

We measured IGF-I and IGFBP-3 in three group of subjects: I. GHD (n: 24), height < -2SD for age (Z score, average +/- SD: -4.2 +/- 1.2), growth velocity < p10 (3.4 +/- 1.0 cm/year) and peak GH level on two GH stimulation tests < 7 ng/ml (1.2 +/- 0.6 ng/ml); II. Short non-GHD (NGHD, n: 32), height of -2.7 +/- 0.9 SD for age, growth velocity < p 25 (3.9 +/- 1.2 cm/year), and peak GH level on two GH stimulation tests > 7 ng/ml (15.3 +/- 6.9 ng/ml), y III. Normal school children (n: 35) with normal heights (-0.17 +/- 0.12 SD) were studied as controls.

RESULTS

IGF-1 and IGFBP-3 were significantly lower in GHD than in NGHD and controls (p < 0.001), and in NGHD than in C (p < 0.001). We defined the normal range of both proteins as +/- 2 SD of the mean of the control group. Using this criteria, IGF-I was low in 21/24 GHD, and in 12/32 NGHD. IGFBP-3 was low in 22/24 GHD, and in 6/32 NGHD. Only 1 GHD patient had both exams in the normal range, suggesting that he is probably NGHD. 4/32 of the NGHD and both exams below normal range, suggesting that they are probably GHD.

CONCLUSIONS

IGF-1 and IGFBP-3 are important tools for the diagnosis of GHD.

Induction of the chemokine beta peptides, MIP-1 alpha and MIP-1 beta, by lipopolysaccharide is differentially regulated by immunomodulatory cytokines gamma-IFN, IL-10, IL-4, and TGF-beta

The macrophage occupies a central role in the host response to invasion, exerting its control over the developing inflammatory response largely through the elaboration of an assortment of endogenous mediators including many cytokines. The beta chemokine peptides, macrophage inflammatory protein [MIP]-1 alpha and MIP-1 beta, are two such effectors markedly up-regulated in macrophages following exposure to bacterial lipopolysaccharide (LPS). These highly homologous peptides, like the other members of the beta chemokine family, exhibit diverse but partially overlapping biological activity profiles, suggesting that the cellular participants and intensity of an inflammatory response may in part be regulated by selective expression of these chemokines. Studies reported here demonstrate that, in contrast to the "balanced" MIP-1 alpha/MIP-1 beta chemokine responses of LPS-stimulated macrophage cultures in vitro, circulating levels of MIP-1 beta are significantly higher than those of MIP-1 alpha following LPS administration in vivo. Further studies have revealed that several immunomodulatory cytokines known to be up-regulated in vivo as a consequence of exposure to an invasive stimulus (gamma-IFN, IL-10, IL-4, and transforming growth factor [TGF]-beta) down-regulated the LPS-induced release of MIP-1 alpha by macrophages in vitro, but spared the MIP-1 beta response. This altered pattern of secretion may explain, at least in part, the high circulating levels of MIP-1 beta relative to MIP-1 alpha observed in vivo in response to LPS challenge.

Effect of renutrition on the proliferation kinetics of PHA stimulated lymphocytes from malnourished children

The fraction of lymphocytes that responded to phytohemagglutinin (PHA) stimulation and initiated cellular proliferation (stimulation index or SI) was determined in groups of healthy and severely malnourished children. SI was determined again in the latter group after a period of nutritional recovery. The proportion of interphasic cells showing PHA response was assessed adding bromodeoxyuridine to the culture, so proliferative nuclei appear big and stain light blue, with dispersed granular chromatin and apparent nucleoli, while non-proliferative nuclei look small, stain red, and have compact and homogeneous chromatin. In mitotic nuclei, differential staining of sister chromatids made it possible to distinguish cells that had gone through one, two and three or more proliferation cycles. Based on the data obtained from interphase nuclei and mitosis, the SI was estimated at 48 and 72 h of culture. SI were higher in lymphocytes from healthy children than in those from children with severe malnutrition, even after the period of nutritional recovery. However, the SI was significantly higher in lymphocytes from malnourished children after nutritional recovery. Although in these children more cells are stimulated, there seems to be still damage that causes a cycling delay.

Context-specific sensitization to naloxone-precipitated withdrawal in hamsters: effect of pimozide

Three experiments were conducted to investigate the development of context-specific sensitization to naloxone-precipitated withdrawal in hamsters. In Experiment 1, animals in group M/S were given morphine (15 mg/kg) injections in a distinctive environment and saline in the home cage. Animals in group S/M were given saline in the distinctive environment and morphine in the home cage, and animals in group S/S were given saline in both environments. All groups were challenged subsequently with naloxone (0.4 mg/kg) in the distinctive environment and then observed for signs of opiate withdrawal. The results showed that group M/S gave more naloxone-precipitated withdrawal signs than each of the other groups, which did not differ from one another. Experiment 2 was designed to test the effect of pimozide on context-specific sensitization to naloxone-precipitated withdrawal. The design was similar to that of Experiment 1 but group P/M/S, which received an injection of pimozide (0.5 mg/kg) 4 h prior to morphine, was added. The results indicated that context-specific sensitization developed as in Experiment 1, except among animals treated with pimozide. Experiment 3 was designed to determine whether pimozide interferes with the development or the expression of context-specific sensitization. Six groups, differing in the frequency and timing of the pimozide injection, were employed. The results indicated that pimozide interfered with context-specific sensitization, whenever it was given. It is concluded that pimozide interferes with the expression of context-specific sensitization, although a separate effect on the development of sensitization is not ruled out.

[Focal and segmental glomerulosclerosis in renal transplantation]

In 179 patients subjected to 186 renal transplants, 30 renal biopsies were performed due to the presence of a proteinuria over 3.5 g/24 h or due to a reduction in glomerular filtration rate. Six of these biopsies, coming from 5 patients, disclosed morphological alterations compatible with focal segmental glomeruloesclerosis. Five of these were due to recurrence of the primary disease (in four patients) and in all, massive proteinuria appeared from 1 to 23 days after transplantation. Two patients with three transplants, evolved to renal failure and required dialysis in a period 12 months as a mean. The third patient, developed a nephrotic syndrome without renal failure and died 14 months after the renal transplant due to a stroke. In the fourth patient, the nephrotic syndrome disappeared 38 days after the transplant and remained with minimal proteinuria until his last follow up visit two years later. The primary disease of the fifth patient is unknown; the nephrotic syndrome appeared 68 months after the transplant and remitted spontaneously in 2 months. The renal biopsy showed focal and segmental lesions with partial effacement of epithelial foot processes. It is concluded that focal segmental glomerulosclerosis recurrence in renal transplant occurs with early massive proteinuria and frequently leads to renal failure and graft loss in no more than two years.

Sister-chromatid exchange (SCE) and cell proliferation in lymphocytes from infected and non-infected children with severe protein calorie malnutrition (PCM)

The frequency of sister-chromatid exchanges (SCE) and the rate of cell proliferation were evaluated through differential staining of sister chromatids in mitogen-stimulated cultured lymphocytes sampled from five well-nourished children, from seven severely malnourished children infected with bacterium, and from 10 severely malnourished children following treatment for infection with antimicrobial drugs 2 weeks before blood sampling. The replication indices at 48 h of culture were higher in both groups of malnourished children than in the well-nourished children, indicating either a faster response to PHA and/or a shorter cell cycle in lymphocytes of these patients. The average frequency of SCE per mitosis was also significantly higher than in the control group. The mitotic index was similar in the three groups of children. The lack of significant difference in response between the two groups of malnourished children suggests that the effects observed at the cytogenetic level are caused by severe malnutrition per se, and not by any associated infection.

Effects of diurnal phase and pimozide on cholecystokinin-elicited hypoactivity in the hamster

Locomotor activity in golden Syrian hamsters was measured following IP injections of cholecystokinin (CCK; 25 micrograms/kg) and pimozide (0.5 mg/kg), the dopamine receptor antagonist. In addition, animals were tested during either the dark or light phase of the diurnal cycle in either dark or light running wheel environments. Results indicated that CCK-elicited hypoactivity was blocked by pimozide and that the effect of CCK was evident only among animals tested during the light phase of the daily cycle. Ambient lighting conditions in the test environment did not modify the drug effects. Independently of any drug effect, locomotor activity was affected by diurnal phase and ambient lighting in the test environment. Animals were more active when tested during the dark phase than during the light phase and locomotor activity was higher under dark than under light ambient conditions. It is concluded that diurnal phase modulates CCK's effect on hamster locomotion and that CCK's effect on locomotion is mediated, in part, by dopaminergic mechanisms.

Blocking naloxone-precipitated withdrawal in rats and hamsters

Three experiments studied the effects of putative antagonists of opiate withdrawal in hamsters and rats. In Experiment 1, the calcium channel antagonists verapamil (20 mg/kg) and nifedipine (20 mg/kg) failed to antagonize naloxone (1 mg/kg)-precipitated withdrawal in hamsters implanted with two 75-mg morphine pellets, whereas clonidine (0.4 mg/kg), the alpha 2-adrenergic agonist, blocked most withdrawal signs. In Experiment 2, clonidine (0.4 mg/kg) and verapamil (20 mg/kg) were tested against naloxone-precipitated withdrawal in hamsters made acutely dependent by a single injection of morphine (15 mg/kg). As in Experiment 1, clonidine but not verapamil was effective. In Experiment 3, the effects of verapamil on naloxone-precipitated withdrawal were studied in morphine-pelleted rats and hamsters. In rats implanted with two morphine pellets, verapamil (20 mg/kg) reversed naloxone-precipitated withdrawal. By contrast, in hamsters implanted with either one or two morphine pellets neither of two doses of verapamil (20 and 30 mg/kg) was effective. These results are discussed in terms of species' differences in sensitivity to calcium channel blockers.

Omental transplantation in the management of chronic traumatic paraplegia. Case report

A 27 year old male patient with chronic traumatic paraplegia received an omental transplant to the spinal cord. During surgery we found 40 percent of the spinal cord hypotrophied, with vascular alterations and abundant scar tissue. Some neurological improvement already started a few days postoperatively. After 36 months of postoperative follow-up he presents with right crural monoparesis (grade 1-4), deep sensation and with sphincter control.

Effect of storage temperature on the stability of the liquid polyvalent antivenom produced in Costa Rica

The effect of storage temperature on the stability of the liquid polyvalent (crotaline) antivenom produced at the Instituto Clodomiro Picado, Costa Rica, was studied during a twelve-month period. The following parameters were evaluated: neutralizing potency against lethal activity of Bothrops asper venom; protein and phenol concentrations; pH; turbidity; safety; and sterility. Analyses were performed each month on different samples of a batch, stored at 4, 23, 30 and 37 degrees C. No significant (P greater than 0.1) variations occurred in potency, protein and phenol concentrations, pH, sterility or safety, at any of the storage temperatures during the study period. However, visual inspection revealed a moderate increase in turbidity of the samples stored at 23, 30 and 37 degrees C, at nine, four and three months, respectively. Culture of samples excluded the possibility of microbial contamination of the product leading to turbidity. Chromatographic and electrophoretic analyses demonstrated that turbidity was caused by the formation of heterogeneous protein aggregates of high molecular weight. Present results support the conclusion that, although storage temperature (up to 37 degrees C for twelve months) does not alter antivenom potency, it significantly influences the formation of protein aggregates. This phenomenon can be prevented by recommending the storage of antivenom at refrigeration temperature.

Arginine vasopressin mediates cardiovascular responses to hypoxemia in fetal sheep

Acute hypoxemia results in hypertension, bradycardia, and cardiac output redistribution in fetal sheep. The blood flow redistribution is produced by differential changes in vascular resistance of various fetal organs. alpha-Adrenergic activity is one of the few vasoconstrictor mechanisms thus far identified in the hypoxemic fetal sheep. Arginine vasopressin (AVP) is a potent vasoconstrictor in adults. Since AVP administration to the normoxic fetus mimics some of the fetal cardiovascular responses to hypoxemia and fetal plasma AVP levels increase with hypoxemia, we examined the hypothesis that AVP modifies the fetal cardiovascular response to hypoxemia by changing the vascular resistance of some fetal vascular beds. To test this we determined fetal systemic arterial pressure and fetal cardiac output and its distribution during hypoxemia with and without the V1 AVP antagonist d(CH2)5-Tyr(Me)AVP. Fourteen fetal sheep (0.79-0.90 of gestation) were chronically catheterized. Five days after surgery fetal hypoxemia was induced by introducing a mixture of 95% N2-5% CO2 (10-20 l/min) into a maternal tracheal catheter. The hypoxemia was maintained for 40 min. Fetal heart rate, systemic arterial blood pressure, and combined ventricular output and its distribution (radiolabeled microspheres) were measured before hypoxemia, at 20 min of hypoxemia alone, and at 20 min of hypoxemia plus either AVP antagonist (n = 5) or NaCl 0.9% (n = 5, controls). Fetal hypertension and bradycardia were partially reversed after the AVP antagonist administration during hypoxia.(ABSTRACT TRUNCATED AT 250 WORDS)