Short-term evaluation of non-absorbable microgranular hydroxyapatite infiltration in the guinea pig subepidermal abdominal region

Non-absorbable microgranular hydroxyapatite was infiltrated into the subepidermal abdominal region of guinea pigs in order to assess the possibility of using this material to correct deficiencies in orbital volume. Microgranular hydroxyapatite (2.0 ml) was subepidermally infiltrated into the abdominal region of 20 guinea pigs. The animals were divided into four experimental groups of 5 animals each, which were killed 7 (G1), 15 (G2), 30 (G3) and 60 (G4) days after infiltration. The area and the largest and smallest diameters of the nodules formed by infiltration were evaluated at the site of infiltration and histological examination was performed. The mean granuloma area was similar in all groups. Histopathological examination showed that the material remained isolated from surrounding tissues by a pseudocapsule that became denser throughout the experiment. A host reaction started with young fibroblastic tissue that evolved to dense tissue until cartilaginous tissue was formed in G4, progressively advancing towards the center of the granuloma from G1 to G4. Non-absorbable microgranular hydroxyapatite is an inert material that was well tolerated by the animals studied, with maintenance of the infiltrated volume, and may perhaps be useful to fill anophthalmic cavities.

Aberrant crypt foci and colon cancer: comparison between a short- and medium-term bioassay for colon carcinogenesis using dimethylhydrazine in Wistar rats

Aberrant crypt foci (ACF) in the colon of carcinogen-treated rodents are considered to be the earliest hallmark of colon carcinogenesis. In the present study the relationship between a short-term (4 weeks) and medium-term (30 weeks) assay was assessed in a model of colon carcinogenesis induced by dimethylhydrazine (DMH) in the rat. Six-week-old male Wistar rats were given subcutaneous injections of DMH (40 mg/kg) twice a week for 2 weeks and killed at the end of the 4th or 30th week. ACF were scored for number, distribution pattern along the colon and crypt multiplicity in 0.1% methylene-blue whole-mount preparations. ACF were distinguished from normal crypts by their larger size and elliptical shape. The incidence, distribution and morphology of colon tumors were recorded. The majority of ACF were present in the middle and distal colon of DMH-treated rats and their number increased with time. By the 4th week, 91.5% ACF were composed of one or two crypts and 8.5% had three or more crypts, while by the 30th week 46.9% ACF had three or more crypts. Thus, a progression of ACF consisting of multiple crypts was observed from the 4th to the 30th week. Nine well-differentiated adenocarcinomas were found in 10 rats by the 30th week. Seven tumors were located in the distal colon and two in the middle colon. No tumor was found in the proximal colon. The present data indicate that induction of ACF by DMH in the short-term (4 weeks) assay was correlated with development of well-differentiated adenocarcinomas in the medium-term (30 weeks) assay.

Reflex control of arterial pressure and heart rate in short-term streptozotocin diabetic rats

Impaired baroreflex sensitivity in diabetes is well described and has been attributed to autonomic diabetic neuropathy. In the present study conducted on acute (10-20 days) streptozotocin (STZ)-induced diabetic rats we examined: 1) cardiac baroreflex sensitivity, assessed by the slope of the linear regression between phenylephrine- or sodium nitroprusside-induced changes in arterial pressure and reflex changes in heart rate (HR) in conscious rats; 2) aortic baroreceptor function by means of the relationship between systolic arterial pressure and aortic depressor nerve (ADN) activity, in anesthetized rats, and 3) bradycardia produced by electrical stimulation of the vagus nerve or by the iv injection of methacholine in anesthetized animals. Reflex bradycardia (-1.4 ± 0.1 vs -1.7 ± 0.1 bpm/mmHg) and tachycardia (-2.1 ± 0.3 vs -3.0 ± 0.2 bpm/mmHg) were reduced in the diabetic group. The gain of the ADN activity relationship was similar in control (1.7 ± 0.1% max/mmHg) and diabetic (1.5 ± 0.1% max/mmHg) animals. The HR response to vagal nerve stimulation with 16, 32 and 64 Hz was 13, 16 and 14% higher, respectively, than the response of STZ-treated rats. The HR response to increasing doses of methacholine was also higher in the diabetic group compared to control animals. Our results confirm the baroreflex dysfunction detected in previous studies on short-term diabetic rats. Moreover, the normal baroreceptor function and the altered HR responses to vagal stimulation or methacholine injection suggest that the efferent limb of the baroreflex is mainly responsible for baroreflex dysfunction in this model of diabetes.

A randomized double-blind study of the short-time treatment of obese patients with nonalcoholic fatty liver disease with ursodeoxycholic acid

In order to determine the effect of ursodeoxycholic acid on nonalcoholic fatty liver disease, 30 patients with body mass indices higher than 25, serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) or gamma-glutamyltransferase (gamma-GT) at least more than 1.5 times the upper limit of normality, and hepatic steatosis demonstrated by ultrasonography were randomized into two groups of 15 patients to receive placebo or 10 mg kg-1 day-1 ursodeoxycholic acid for three months. Abdominal computed tomography was performed to quantify hepatic fat content, which was significantly correlated with histological grading of steatosis (r s = -0.83, P < 0.01). Patient body mass index remained stable for both groups throughout the study, but a significant reduction in mean (± SEM) serum levels of ALT, AST and gamma-GT was observed only in the treated group (ALT = 81.2 ± 9.7, 44.8 ± 7.7, 48.1 ± 7.7 and 52.2 ± 6.3 IU/l at the beginning and after the first, second and third months, respectively, N = 14, P < 0.05). For the placebo group ALT values were 66.4 ± 9.8, 54.5 ± 7, 60 ± 7.6 and 43.7 ± 5 IU/l, respectively. No alterations in hepatic lipid content were observed in these patients by computed tomography examination (50.2 ± 4.2 Hounsfield units (HU) at the beginning versus 51.1 ± 4.1 HU at the third month). These results show that ursodeoxycholic acid is able to reduce serum levels of hepatic enzymes in patients with nonalcoholic fatty liver disease, but this effect is not related to modifications in liver fat content.

Differential role of entorhinal and hippocampal nerve growth factor in short- and long-term memory modulation

We studied the effects of infusion of nerve growth factor (NGF) into the hippocampus and entorhinal cortex of male Wistar rats (250-300 g, N = 11-13 per group) on inhibitory avoidance retention. In order to evaluate the modulation of entorhinal and hippocampal NGF in short- and long-term memory, animals were implanted with cannulae in the CA1 area of the dorsal hippocampus or entorhinal cortex and trained in one-trial step-down inhibitory avoidance (foot shock, 0.4 mA). Retention tests were carried out 1.5 h or 24 h after training to measure short- and long-term memory, respectively. Immediately after training, rats received 5 µl NGF (0.05, 0.5 or 5.0 ng) or saline per side into the CA1 area and entorhinal cortex. The correct position of the cannulae was confirmed by histological analysis. The highest dose of NGF (5.0 ng) into the hippocampus blocked short-term memory (P < 0.05), whereas the doses of 0.5 (P < 0.05) and 5.0 ng (P < 0.01) NGF enhanced long-term memory. NGF administration into the entorhinal cortex improved long-term memory at the dose of 5.0 ng (P < 0.05) and did not alter short-term memory. Taken as a whole, our results suggest a differential modulation by entorhinal and hippocampal NGF of short- and long-term memory.

Cultural adaptation and validation of the "Kidney Disease and Quality of Life - Short Form (KDQOL-SF™ 1.3)" in Brazil

The objective of the present study was to translate the Kidney Disease Quality of Life - Short Form (KDQOL-SF™1.3) questionnaire into Portuguese to adapt it culturally and validate it for the Brazilian population. The KDQOL-SF was translated into Portuguese and back-translated twice into English. Patient difficulties in understanding the questionnaire were evaluated by a panel of experts and solved. Measurement properties such as reliability and validity were determined by applying the questionnaire to 94 end-stage renal disease patients on chronic dialysis. The Nottingham Health Profile Questionnaire, the Karnofsky Performance Scale and the Kidney Disease Questionnaire were administered to test validity. Some activities included in the original instrument were considered to be incompatible with the activities usually performed by the Brazilian population and were replaced. The mean scores for the 19 components of the KDQOL-SF questionnaire in Portuguese ranged from 22 to 91. The components "Social support" and "Dialysis staff encouragement" had the highest scores (86.7 and 90.8, respectively). The test-retest reliability and the inter-observer reliability of the instrument were evaluated by the intraclass correlation coefficient. The coefficients for both reliability tests were statistically significant for all scales of the KDQOL-SF (P < 0.001), ranging from 0.492 to 0.936 for test-retest reliability and from 0.337 to 0.994 for inter-observer reliability. The Cronbach's alpha coefficient was higher than 0.80 for most of components. The Portuguese version of the KDQOL-SF questionnaire proved to be valid and reliable for the evaluation of quality of life of Brazilian patients with end-stage renal disease on chronic dialysis.

Occurrence of Haemophilus influenzae strains in three Brazilian states since the introduction of a conjugate Haemophilus influenzae type b vaccine

Few vaccines in history have induced such a dramatic decline in incidence over such a short period of time as the Haemophilus influenzae type b (Hib) conjugate. This vaccine was introduced in 1988 in the United States, but only in 1999 was Hib immunization introduced by the Brazilian Ministry of Health as part of the routine infant National Immunization Program. The authors analyzed 229 H. influenzae (Hi) isolates from Public Health Laboratories in three Brazilian states: Pernambuco (Northeast, N = 54), Santa Catarina (South, N = 19), and Rio de Janeiro (Southeast, N = 156). The isolates were collected from Brazilian children 0-10 years of age with meningitis and other infections from 1990 to 2003 and were part of the research collection of the National Institute of Quality Control in Health, FIOCRUZ. Bacterial strains were characterized by serotyping and biotyping. During the pre-vaccination period the prevalence infection due to Hib was of 165 isolates and only 2 non-b Hi among all the notified meningitis infections caused by Hi. Our results showed a significant decrease in the prevalence of Hib meningitis from 165 to 33 isolates after 1999. However, during the post-vaccination period of 2001-2003 we observed an increase in the number of non-b Hi isolates: only 2 non-b strains isolated from 1990 to 1999 and 29 from 1999 to 2003. Based on the present data, the authors emphasize the need for more sensitive epidemiological and bacteriological studies aiming the improvement of the available Hib vaccine, in order to protect the susceptible population to infections due to other serological types of Hi and the reevaluation of immunization schedules used by the National Immunization Program.

Short-lasting systemic and regional benefits of early crystalloid infusion after intravenous inoculation of dogs with live Escherichia coli

We investigated the systemic and regional hemodynamic effects of early crystalloid infusion in an experimental model of septic shock induced by intravenous inoculation with live Escherichia coli. Anesthetized dogs received an intravenous infusion of 1.2 x 10(10) cfu/kg live E. coli in 30 min. After 30 min of observation, they were randomized to controls (no fluids; N = 7), or fluid resuscitation with lactated Ringer's solution, 16 ml/kg (N = 7) or 32 ml/kg (N = 7) over 30 min and followed for 120 min. Cardiac index, portal blood flow, mean arterial pressure, systemic and regional oxygen-derived variables, blood lactate, and gastric PCO2 were assessed. Rapid and progressive cardiovascular deterioration with reduction in cardiac output, mean arterial pressure and portal blood flow (~50, ~25 and ~70%, respectively) was induced by the live bacteria challenge. Systemic and regional territories showed significant increases in oxygen extraction and in lactate levels. Significant increases in venous-arterial (~9.6 mmHg), portal-arterial (~12.1 mmHg) and gastric mucosal-arterial (~18.4 mmHg) PCO2 gradients were also observed. Early fluid replacement, especially with 32 ml/kg volumes of crystalloids, promoted only partial and transient benefits such as increases of ~76% in cardiac index, of ~50% in portal vein blood flow and decreases in venous-arterial, portal-arterial, gastric mucosal-arterial PCO2 gradients (7.2 ± 1.0, 7.2 ± 1.3 and 9.7 ± 2.5 mmHg, respectively). The fluid infusion promoted only modest and transient benefits, unable to restore the systemic and regional perfusional and metabolic changes in this hypodynamic septic shock model.

High frequencies of plexiform neurofibromas, mental retardation, learning difficulties, and scoliosis in Brazilian patients with neurofibromatosis type 1

A clinical study of Brazilian patients with neurofibromatosis type 1 (NF1) was performed in a multidisciplinary Neurofibromatosis Program called CEPAN (Center of Research and Service in Neurofibromatosis). Among 55 patients (60% females, 40% males) who met the NIH criteria for the diagnosis of NF1, 98% had more than six café-au-lait patches, 94.5% had axillary freckling, 45% had inguinal freckling, and 87.5% had Lisch nodules. Cutaneous neurofibromas were observed in 96%, and 40% presented plexiform neurofibromas. A positive family history of NF1 was found in 60%, and mental retardation occurred in 35%. Some degree of scoliosis was noted in 49%, 51% had macrocephaly, 40% had short stature, 76% had learning difficulties, and 2% had optic gliomas. Unexpectedly high frequencies of plexiform neurofibromas, mental retardation, learning difficulties, and scoliosis were observed, probably reflecting the detailed clinical analysis methods adopted by the Neurofibromatosis Program. These same patients were screened for mutations in the GAP-related domain/GRD (exons 20-27a) by single-strand conformation polymorphism. Four different mutations (Q1189X, 3525-3526delAA, E1356G, c.4111-1G>A) and four polymorphisms (c.3315-27G>A, V1146I, V1317A, c.4514+11C>G) were identified. These data were recently published.

Errors in nonword repetition: bridging short- and long-term memory

According to the working memory model, the phonological loop is the component of working memory specialized in processing and manipulating limited amounts of speech-based information. The Children's Test of Nonword Repetition (CNRep) is a suitable measure of phonological short-term memory for English-speaking children, which was validated by the Brazilian Children's Test of Pseudoword Repetition (BCPR) as a Portuguese-language version. The objectives of the present study were: i) to investigate developmental aspects of the phonological memory processing by error analysis in the nonword repetition task, and ii) to examine phoneme (substitution, omission and addition) and order (migration) errors made in the BCPR by 180 normal Brazilian children of both sexes aged 4-10, from preschool to 4th grade. The dominant error was substitution [F(3,525) = 180.47; P < 0.0001]. The performance was age-related [F(4,175) = 14.53; P < 0.0001]. The length effect, i.e., more errors in long than in short items, was observed [F(3,519) = 108.36; P < 0.0001]. In 5-syllable pseudowords, errors occurred mainly in the middle of the stimuli, before the syllabic stress [F(4,16) = 6.03; P = 0.003]; substitutions appeared more at the end of the stimuli, after the stress [F(12,48) = 2.27; P = 0.02]. In conclusion, the BCPR error analysis supports the idea that phonological loop capacity is relatively constant during development, although school learning increases the efficiency of this system. Moreover, there are indications that long-term memory contributes to holding memory trace. The findings were discussed in terms of distinctiveness, clustering and redintegration hypotheses.

Salt and insulin sensitivity after short and prolonged high salt intake in elderly subjects

Salt sensitivity and insulin resistance are correlated with higher cardiovascular risk. There is no information about changes in salt sensitivity (SS) and insulin sensitivity (IS) after a chronic salt overload in humans. The aim of this study was to evaluate these parameters in the elderly. Seventeen volunteers aged 70.5 ± 5.9 years followed a low-salt diet (LSD) for 1 week and a high-salt diet (HSD) for 13 weeks. We evaluated SS after one week (HSD1) and after 13 weeks (HSD13), and subjects’ IS and lipids on their usual diet (UD) at HSD1, and at HSD13. Blood pressure (BP) was measured at each visit and ambulatory blood pressure monitoring (ABPM) was performed twice. SS was the same at HSD1 and HSD13. Systolic BP was lower on LSD than on UD (P = 0.01), HSD1 (P < 0.01) and HSD13 (P < 0.01). When systolic and diastolic BP were evaluated by ABPM, they were higher at HSD13 during the 24-h period (P = 0.03 and P < 0.01) and during the wakefulness period (P = 0.02 and P < 0.01) compared to the UD. Total cholesterol was higher (P = 0.04) at HSD13 than at HSD1. Glucose and homeostasis model assessment (HOMA) were lower at HSD1 (P = 0.02 and P = 0.01) than at HSD13. Concluding, the extension of HSD did not change the SS in an elderly group. The higher IS found at HSD1 did not persist after a longer HSD. A chronic HSD increased BP as assessed by ABPM.

Short-term exposure of mice to cigarette smoke and/or residual oil fly ash produces proximal airspace enlargements and airway epithelium remodeling

Chronic obstructive pulmonary disease (COPD) is associated with inflammatory cell reactions, tissue destruction and lung remodeling. Many signaling pathways for these phenomena are still to be identified. We developed a mouse model of COPD to evaluate some pathophysiological mechanisms acting during the initial stage of the disease. Forty-seven 6- to 8-week-old female C57/BL6 mice (approximately 22 g) were exposed for 2 months to cigarette smoke and/or residual oil fly ash (ROFA), a concentrate of air pollution. We measured lung mechanics, airspace enlargement, airway wall thickness, epithelial cell profile, elastic and collagen fiber deposition, and by immunohistochemistry transforming growth factor-β1 (TGF-β1), macrophage elastase (MMP12), neutrophils and macrophages. We observed regional airspace enlargements near terminal bronchioles associated with the exposure to smoke or ROFA. There were also increases in airway resistance and thickening of airway walls in animals exposed to smoke. In the epithelium, we noted a decrease in the ciliated cell area of animals exposed to smoke and an increase in the total cell area associated with exposure to both smoke and ROFA. There was also an increase in the expression of TGF-β1 both in the airways and parenchyma of animals exposed to smoke. However, we could not detect inflammatory cell recruitment, increases in MMP12 or elastic and collagen fiber deposition. After 2 months of exposure to cigarette smoke and/or ROFA, mice developed regional airspace enlargements and airway epithelium remodeling, although no inflammation or increases in fiber deposition were detected. Some of these phenomena may have been mediated by TGF-β1.

Coping with genetic diversity: the contribution of pathogen and human genomics to modern vaccinology

Vaccine development faces major difficulties partly because of genetic variation in both infectious organisms and humans. This causes antigenic variation in infectious agents and a high interindividual variability in the human response to the vaccine. The exponential growth of genome sequence information has induced a shift from conventional culture-based to genome-based vaccinology, and allows the tackling of challenges in vaccine development due to pathogen genetic variability. Additionally, recent advances in immunogenetics and genomics should help in the understanding of the influence of genetic factors on the interindividual and interpopulation variations in immune responses to vaccines, and could be useful for developing new vaccine strategies. Accumulating results provide evidence for the existence of a number of genes involved in protective immune responses that are induced either by natural infections or vaccines. Variation in immune responses could be viewed as the result of a perturbation of gene networks; this should help in understanding how a particular polymorphism or a combination thereof could affect protective immune responses. Here we will present: i) the first genome-based vaccines that served as proof of concept, and that provided new critical insights into vaccine development strategies; ii) an overview of genetic predisposition in infectious diseases and genetic control in responses to vaccines; iii) population genetic differences that are a rationale behind group-targeted vaccines; iv) an outlook for genetic control in infectious diseases, with special emphasis on the concept of molecular networks that will provide a structure to the huge amount of genomic data.

Short-term levosimendan treatment protects rat testes against oxidative stress

The objective of this study was to evaluate the effect of short-term levosimendan exposure on oxidant/antioxidant status and trace element levels in the testes of rats under physiological conditions. Twenty male Wistar albino rats were randomly divided into two groups of 10 animals each. Group 1 was not exposed to levosimendan and served as control. Levosimendan (12 µg/kg) diluted in 10 mL 0.9% NaCl was administered intraperitoneally to group 2. Animals of both groups were sacrificed after 3 days and their testes were harvested for the determination of changes in tissue oxidant/antioxidant status and trace element levels. Tissue malondialdehyde (MDA) was significantly lower in the levosimendan group (P < 0.001) than in the untreated control group and superoxide dismutase and glutathione peroxidase (GSH-Px) levels were significantly higher in the levosimendan group (P < 0.001). Carbonic anhydrase, catalase and GSH levels were not significantly different from controls. Mg and Zn levels of testes were significantly higher (P < 0.001) and Co, Pb, Cd, Mn, and Cu were significantly lower (P < 0.001) in group 2 compared to group 1. Fe levels were similar for the two groups (P = 0.94). These results suggest that 3-day exposure to levosimendan induced a significant decrease in tissue MDA level, which is a lipid peroxidation product and an indicator of oxidative stress, and a significant increase in the activity of an important number of the enzymes that protect against oxidative stress in rat testes.

A study on the short-term effect of cafeteria diet and pioglitazone on insulin resistance and serum levels of adiponectin and ghrelin

The interaction between ghrelin and adiponectin is still controversial. We investigated the effect of cafeteria diet and pioglitazone on body weight, insulin resistance, and adiponectin/ghrelin levels in an experimental study on male Wistar rats. The animals were divided into four groups of 6 rats each, and received balanced chow with saline (CHOW-O) or pioglitazone (CHOW-P), or a cafeteria diet with saline (CAFE-O) or pioglitazone (CAFE-P). The chow/cafeteria diets were administered for 35 days, and saline/pioglitazone (10 mg·kg body weight-1·day-1) was added in the last 14 days prior to euthanasia. CAFE-O animals had a higher mean final weight (372.5 ± 21.01 g) than CHOW-O (317.66 ± 25.11 g, P = 0.017) and CHOW-P (322.66 ± 28.42 g, P = 0.035) animals. Serum adiponectin levels were significantly higher in CHOW-P (55.91 ± 20.62 ng/mL) than in CHOW-O (30.52 ± 6.97 ng/mL, P = 0.014) and CAFE-O (32.54 ± 9.03 ng/mL, P = 0.027) but not in CAFE-P. Higher total serum ghrelin levels were observed in CAFE-P compared to CHOW-P animals (1.65 ± 0.69 vs 0.65 ± 0.36 ng/mL, P = 0.006). Likewise, acylated ghrelin levels were higher in CAFE-P (471.52 ± 195.09 pg/mL) than in CHOW-P (193.01 ± 87.61 pg/mL, P = 0.009) and CAFE-O (259.44 ± 86.36 pg/mL, P = 0.047) animals. In conclusion, a cafeteria diet can lead to a significant weight gain. Although CAFE-P animals exhibited higher ghrelin levels, this was probably related to food deprivation rather than to a direct pharmacological effect, possibly attenuating the increase in adiponectin levels.