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Biomedical subjects

H Hurtado

Publications and source records attributed to H Hurtado.

18 recordsLinked to original sources
PubMed2000

Nerve growth factor and neurotrophin-3 modulate the rabies infection of adult sensory neurons in primary cultures.

With the aim of determining if the proportion of rabies virus (RV)-infected adult neurons from dorsal root ganglion are affected by in vitro treatment with different neurotrophins, experiments using Nerve Growth Factor (NGF), Brain Derived Neurotrophic Factor (BDNF) or Neurotrophin-3 (NT-3) as supplements for cells in culture were performed. Cultures treated with three different concentrations of each of the neurotrophins mentioned were infected with Challenge Virus Standard RV strain. An indirect immunoperoxidase technique was performed for the detection and counting of infected cells. NGF (2 ngml(-1) and 10 ngml(-1)) and NT-3 (1 ngml(-1) and 5 ngml(-1)) induced a significant reduction of infected neurons. None of the cultures treated with BDNF showed changes in the percentage of infected neurons. Likewise, the proportion of infected non-neuronal cells (Schwann cells and fibroblasts) was not altered by the treatment with neurotrophins. In addition, morphometric analysis of total and virus-immunoreactive neurons in culture were carried out, the neurotrophin treatment induced variations in the profile of neurons preferentially infected, since cell diameters in the infected cell population are different in the presence of NGF and NT-3. Data presented here could indicate a putative participation of neurotrophin receptor or biochemical modifications induced by neurotrophin treatment that affect the infection. The primary culture of dorsal root ganglion cells from adult mice is a very useful model for studying the basic phenomena of the RV-neuron interaction.

Animals↗
PubMed2000

An anterograde degeneration study of the distribution of regenerating rat myelinated fibers in the silicone chamber model.

Specificity of reinnervation after a peripheral nerve lesion has given rise to considerable controversy. As a contribution to solving this issue we have evaluated the specificity of reinnervation of the peroneal nerve after a complete transection of the sciatic nerve repaired with an 8 mm silicone tube, leaving a 4 mm gap between the nerve stumps. Our findings reveal unspecificity of reinnervation of the distal peroneal branch. This lack of specificity is shown by a random distribution of fibers originating from both proximal branches at the level of the tube and at distal peroneal and tibial branches, argue against specificity of regeneration in this model.

Animals↗
PubMed1997

Partial inhibition of the in vitro infection of adult mouse dorsal root ganglion neurons by rabies virus using nicotinic antagonists.

The infection of target cells by rabies virus is effected through membrane receptors. Several authors have suggested that nicotinic receptors could be used by this virus, but no direct experimental evidence is available. In this study mouse dorsal root ganglia cells were treated with various nicotinic antagonists (dihydro-beta-eritroidine, mecamilamine, d-tubocurarin, hexametonium, alpha-bungarotoxin and erabutoxin). After incubation, the cultures were infected with rabies virus. Cells were fixed, and processed for immunodetection of rabies virus. Treatment with mecamilamine or d-tubocurarine reduced the percentage of infected neurons. None of the antagonists tested changed the percentage of infected non-neuronal cells.

Animals↗
PubMed1997

Prenatal biopsychosocial risk assessment and low birthweight.

A double-blind prospective study was conducted to compare the predictive value of a prenatal biomedical risk scale (PBRS) and a prenatal biopsychosocial risk assessment (PBRAS) with respect to low birthweight. All obstetric patients at seven health centers located in Argentina, Colombia, Honduras, and Uruguay from November 1992 through January 1994 whose initial prenatal visits occurred between the 14th and 28th week of gestation were invited to participate. Information was obtained on 979 mother-infant pairs. High PBRS scores showed sensitivity of 62.1% and specificity of 81.3%, positive predictive value (PPV) of 45.3% and negative predictive value (NPV) of 89.5%, with respect to low birthweight. With the addition of the psychosocial factors (PBRAS), sensitivity of 75.7% and specificity of 76.1%, PPV of 55.1% and NPV of 88.9% were observed. The prospective cohort design of this study provides a strong basis for conclusion that an evaluation of the prenatal biopsychosocial risk (as operationalized by the PBRAS) adjusted for other variables such as length of gestation, neonatal APGAR, perinatal mortality, socioeconomic status, drinking and smoking improves the positive predictive value of the assessment of women who may give birth to newborns with low birthweight (P < 0.01).

Adolescent↗
PubMed1992

Antepartum biopsychosocial risk and perinatal outcome.

This paper describes a study of biomedical and psychosocial risks and the perinatal outcome. Two hundred nineteen pregnant women completed three instruments to identify their biomedical and psychosocial risk: anxiety, family function, life events. Biomedical risk was assessed through analyses of self-reported health histories. Information on complications of pregnancy, labor, and delivery was obtained from the hospital delivery records. In the sample studied, biomedical risk alone was not substantially related to perinatal complications. Four psychosocial items were the best psychosocial predictors of perinatal complications: emotional tension; depressive humor; neurovegetative symptoms of anxiety; and dissatisfaction with the time, space, and money shared with the family (p < 0.05). The interaction between these critical psychosocial items and biomedical risk also reliably predicted complications (p < 0.00001). The results of this study suggest that psychosocial risk assessment alone and in interaction with biomedical risk assessment may significantly improve the ability to identify women who may experience perinatal complications.

Adolescent↗
PubMed1990

Effects of dibutyryl cyclic adenosine monophosphate, ACTH(4-10) and gangliosides on nerve fiber regeneration after rat sciatic nerve tubulization.

Tubulization of sectioned rat sciatic nerves was used to evaluate the effect of dibutyryl cyclic adenosine monophosphate (db-cAMP), a fragment of the adrenocorticotrophic hormone (ACTH(4-10] and gangliosides on the regrowth of injured nerve processes. Four weeks post-operative, the number of myelinated fibers was counted at different levels of the lesioned sciatic nerves and the endoneurium surface of the bridging structure in the tube was measured. Animals treated with gangliosides and db-AMPc showed statistically significant differences compared to vehicle treated rats. The gangliosides have shown a beneficial effect but db-cAMP diminished the number of myelinated fibers. In this case, an implication of Schwann cell mitosis and migration is discussed. In spite of better results obtained in ACTH(4-10)-treated animals compared to controls, the differences did not attain a statistically significant level. These experiments confirm the beneficial effect of gangliosides on peripheral nerve regeneration and reveal a negative effect of db-cAMP in the regeneration chamber model.

Adrenocorticotropic Hormone↗
PubMed1990

Rat sciatic nerve regeneration within an acrylic semipermeable tube and comparison with a silicone impermeable material.

Sectioned rat sciatic nerves were placed in tubes to study the regrowth of injured nerve processes. First, we characterized quantitatively the regeneration of myelinated fibers at different levels of an acrylic semipermeable tube, from two to 27 weeks postoperatively. From the fifth week, myelinated fiber counts at mid-tube level were equal to the value of an intact nerve, but at the distal part the number of fibers exceeded both mid-tube level and unsectioned nerve values. At the proximal part of the tube an important fiber disorganization was observed. Second, we have compared acrylic semipermeable and totally impermeable silicone tubes at four and 27 weeks postoperatively. In terms of the number of myelinated fibers and the surface of the endoneurium at the mid-tube level, the most effective tube was the impermeable one. This study points out the importance of the tube wall permeability in nerve regeneration.

Acrylates↗
PubMed1989

Renal size and function in diabetic nephropathy.

The purpose of this investigation was to study in a group of diabetics with varying degrees of renal failure, the relationship of renal size to the degree of renal function. A literature search of the past 25 years has failed to document a precise relationship between structure and function in this setting. Patients were admitted, and sex, age, race, serum creatinine levels, renal size and mean blood pressure were ascertained. Patients with polycystic kidney disease were, obviously, excluded. The group consisted of 26 diabetics, divided into two groups based on previous (prior to onset of uremia) insulin and ketone status. Interestingly, there was no significant difference between groups with insulin-dependent diabetes mellitus (IDDM) and non-insulin-dependent diabetes mellitus (NIDDM) as regards mean blood pressure (106.5 +/- 15.3 mm Hg vs. 108.9 +/- 17.64 mm Hg; t = 0.3607892, p = 0.9). Mean kidney length was inversely related to serum creatinine level (r = 0.3980, n = 26, p less than 0.05). There was no correlation between mean renal length and mean blood pressure (r = 0.189, p greater than 0.05). However, there was a significantly higher proportion of larger kidneys (11 cm or more) in the IDDM group than in the NIDDM group (Fischer's exact test; p less than 0.0001) which was related neither to age nor blood pressure. In this paper, we show an inverse correlation between kidney length and serum creatinine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

[Toxic effect of fluid accumulated within silicone regeneration chambers on the survival and proliferation of fibroblasts of the heart of newborn rats].

Liquid collected from silicone impermeable sciatic regeneration chambers, fetal calf serum (FCS) and rat serum at different dilutions were tested on fibroblasts originating from hearts of newborn rats. The lower liquid dilutions presented a toxic effect. This effect was not counteracted by simultaneous addition of FCS at the same dilution. No evidence of a trophic activity was found in the liquid.

Animals↗
PubMed1987

Rat sciatic nerve regeneration in semipermeable artificial tubes.

The regeneration of the sciatic nerve in Wistar rats across a 10-mm gap, within a semipermeable chamber was examined. The sequence of regeneration can be summarized as follows: (i) formation of a fibrin-containing matrix; (ii) invasion of this matrix by fibroblasts, forming two populations defined by their relative position within the matrix; (iii) the appearance of blood vessels; (iv) bridge formation; and (v) colonization of the bridge by nerve fibers. After 4 weeks, the number of myelinated fibers and the regenerate surface were studied at midtube level. Two and four weeks after the operation, both myelinated and unmyelinated leading fibers were detected and their distances from proximal stump measured. The results approach those reported in the literature for impermeable tubes, but not those obtained for fully permeable ones.

Acrylates↗
PubMedDate not supplied

Response to measles revaccination among Bolivian school-aged children.

The response to measles revaccination was evaluated in 1994 among 202 Bolivian school-aged children whose antibody levels were below 200 miu (milli-international units) by haemagglutination inhibition (HI) in a large-scale serosurvey conducted in Santa Cruz one year earlier. Of the 202 revaccinated children, 164 (82%) had seroconverted between the 1993 serosurvey and the pre-revaccination blood sample. A measles outbreak occurred in Santa Cruz 6 months before the revaccination. Among the seroconvertors, only 6% gave a history of measles, and 15% a history of contact with a case of measles. All 20 children with undetectable HI antibody pre-revaccination, and all 6 children with levels below 100 miu, seroconverted after revaccination. The geometric mean titres by HI at 4 weeks after revaccination were 2018 miu (95% confidence limits [95% CL] 1143, 3564) and 398 miu (95% CL 254, 625) in the 2 groups, respectively. Six of 9 children with pre-revaccination antibody titres of 100-199 miu also seroconverted. No child demonstrated a measles-specific immunoglobulin M response. Among the 29 children who seroconverted and were followed up at one year after revaccination, 15(52%) showed a fourfold or greater decline in antibody levels, which in 8 fell to levels below 200 miu. This study confirmed the observation that revaccination is successful in producing an antibody response in children with low or undetectable pre-revaccination titres, but it also confirmed that vaccine-induced immunity wanes rapidly.

Adolescent↗
PubMedDate not supplied

Rabies virus infection of cultured adult mouse dorsal root ganglion neurons.

An in vitro model of adult dorsal root ganglion neurons infection by rabies virus is described, Viral marked neurotropism is observed, and the percentage and the degree of infection of the neurons is higher than in non neuronal cells, even if neurons are the minority of the cells in the culture. The neuritic tree is also heavily infected by the virus.

Animals↗