Alteración de la mineralización de tejidos dentarios y paradentarios inducida por bifosfonatos en ratas Wistar / Alteration of mineralization of dental and paradental tissues induced by biphosphonates in Wistar rats

Desórdenes sistémicos de la homeostasis mineral o fallas en la mineralización de la matriz extracelular pueden afectar tanto a las piezas dentarias como a su aparato de sostén, conduciendo al fracaso de los tratamientos odontológicos. Existe poca evidencia científica sobre modelos animales que permitan es-tudiar la respuesta de tejidos dentarios/paradenta-rios frente a este tipo de desórdenes. El objetivo del presente trabajo fue estudiar experimentalmente al-teraciones de la biomineralización inducidas por bis-fosfonatos en ratas Wistar. Para ello, 20 ratas Wistar hembras y machos (35±10 g) fueron tratados con 20 mg/kg de etidronato bisódico (EHBP) o solución fi-siológica (control) vía intraperitoneal 5 veces por se-mana durante 3 semanas. Luego de la eutanasia, se extrajeron las mandíbulas para su procesamiento y análisis histológico (H&E). Mediante microfotografías digitales se evaluó: área ósea/área total, espesor de ligamento periodontal, áreas de dentina y de cemen-to. Los resultados se analizaron estadísticamente mediante el test T de Student para comparaciones entre grupos y el test ANOVA de 2 vías para las com-paraciones intersexo. Los grupos EHBP presentaron mayor proporción de osteoide, dentina y cemento no mineralizados respecto a los controles, siendo más marcadas las diferencias en las hembras. Las hem-bras del grupo EHBP mostraron una disminución significativa en el espesor del ligamento periodontal respecto de los controles, aunque esta tendencia no se observó en machos. Los resultados del presente estudio demuestran que el EHBP, en la dosis y tiempo estudiados, altera los procesos de biomineralización tanto del tejido óseo como de los tejidos dentarios (AU)

Systemic disorders of mineral homeostasis or alterations in the mineralization of the extracellular matrix can affect both dental and supportive tissues, leading to the failure of dental treatments. There is a lack of scientific information about animal models that allow to study the response of dental/paradental tissues in this type of disorders. The aim of the present work was to study the biomineralization alterations induced by bisphosphonates in Wistar rats and to study the response of dental and paradental tissues. Twenty Wistar rats (35±10 g) were divided in control (females, males) and EHBP (females, males) groups. The EHBP group received 20 mg/kg of ethidronate bisodium intraperitoneally 5 times a week for 3 weeks, while the control group received saline solution. After euthanasia, mandibles were resected and processed histologically to obtained oriented sections for H&E staining. Photomicrographs were used to evaluate: Bone area/total area, periodontal ligament thickness, dentin and cement area. Results were statistically analyzed using the Student's T test for comparisons between groups and the 2-way ANOVA test for male and female comparisons. The EHBP groups showed a higher amount of non-mineralized osteoid, dentin and cement compared to control groups, being more evident in females. Females in the EHBP group showed a significant decrease in periodontal ligament thickness compared to controls, although this profile was not observed in males. The results of the present study demonstrate that EHBP, at the dose and time studied, alters the biomineralization processes of both bone and dental tissues (AU)

Toxicity of cypermethrin on the neotropical lacewing Chrysoperla externa (Neuroptera: Chrysopidae).

The generalist predator Chrysoperla externa (Neuroptera: Chrysopidae) is distributed in the Neotropical Region and presents a strong potential as a biological control agent due to its easily rearing, high voracity and tolerance to several pesticides. This species feeds on relevant pests such as aphids, whiteflies, trips and various lepidopterans. In Argentina, an indiscriminate chemical control with broad spectrum pesticides is still the first option for controlling pests causing resistance problems and reduction of beneficial organisms. Therefore, it would be desirable that predators or parasitoids develop tolerance or resistance as phytophagous pests for their maintenance in the agricultural ecosystems. The objective of this work was to evaluate the tolerance of C. externo to the pyrethroid cypermethrin by topical exposure in laboratory conditions. The symptoms evaluated were tremors, movement, knockdown, inability to walk due to being glued. Recovery from poisoning symptoms was also evaluated. Six different concentrations of the pesticide, including the full field one, were tested. The exposure method was by topical applications on third larval instar. A low toxicity on larvae at 24 h post-treatment was observed, even at the highest concentration evaluated. Most of treated individuals looked normal at 24 h post-treatment; those who were knocked down showed a complete recovery between 48 and 72 h post-treatment. C externa demonstrated a high tolerance to pyrethroids. This could be due to the activity involved in pyrethroids biotransformation (for example, esterases and mixed-function oxidases), or to a low sensitivity of the molecular target. Future studies should be addressed at biochemical and molecular levels to complete our knowledge about insecticide effects on this predator.

High resistance to lipid peroxidation of bird heart mitochondria and microsomes: Effects of mass and maximum lifespan.

The aim of this investigation was to study the connection between body size, fatty acid composition and sensitivity to lipid peroxidation of heart mitochondria and microsomes isolated from different size bird species: manon (Lonchura striata), quail (Coturnix coturnix var japonica), pigeon (Columba livia), duck (Cairina moschata) and goose (Anser anser), representing a 372-fold range of body mass. Fatty acids of total lipids were determined using gas chromatography and lipid peroxidation was evaluated with a chemiluminescence assay. The fatty acids present in heart organelles of the different bird species analyzed showed a small number of significant allometric trends. In mitochondria, from the individual fatty acid data, palmitoleic acid (C16:1 n7) increased allometrically (r=0.878), while stearic acid (C18:0) was negatively related to body mass (r=-0.903). Interestingly, none of the calculated fatty acid variables, the average fatty acid saturated, monounsaturated, polyunsaturated (PUFA) and the unsaturation index (UI) was established to show significant body size-related variations. In heart microsomes, the content of C18:0 was significantly smaller (r=-0.970) in the birds of greater size. A significant allometric increase in linoleic acid (C18:2 n6) (r=0.986), polyunsaturated (r=0.990) and UI (r=0.904) was observed in the larger birds. The total n6 fatty acids of heart mitochondria did not show significant differences when it was correlated to body mass of the birds. Moreover, positive allometric relationships were shown for microsomes. The total n3 fatty acids of heart mitochondria and microsomes indicated no significant correlations to body mass of birds. The C16:1 n7, C18:0 in mitochondria and C18:0, C18:2 n6, PUFA, UI and PUFA n6 in microsomes showed significant differences when they were correlated to maximum life span (MLSP) of birds. As light emission=chemiluminescence originated from heart organelles was not statistically significant, a lack of correlation between the sensitivity to lipid peroxidation and body size or maximum life span was obtained. These results indicate that the high resistance of bird hearts to the attack by free radicals is body size-independent and would be related to the preservation of cardiac function.

An allometric study of fatty acids and sensitivity to lipid peroxidation of brain microsomes and mitochondria isolated from different bird species.

The objective of this investigation was to examine the relationship between body size, fatty acid composition and sensitivity to lipid peroxidation of mitochondria and microsomes isolated from the brain of different size bird species: manon, quail, pigeon, duck and goose, representing a 372-fold range of body mass. Fatty acids of total lipids were determined using gas chromatography and lipid peroxidation was evaluated using a chemiluminescence assay. The allometric study of the fatty acids present in brain mitochondria and microsomes of the different bird species showed a small number of significant allometric trends. In mitochondria the percentage of monounsaturated fatty acids, was significantly lower in the larger birds (r=-0.965; P<0.008). The significant allometric increase in 18:2 n-6; linoleic acid (r=0.986; P<0.0143), polyunsaturated (r=0.993; P<0.007) and total unsaturated (r=0.966; P<0.034) in brain microsomes but not in mitochondria may indicate a preferential incorporation of this fatty acid in the brain endoplasmic reticulum of the larger bird species. The brain of all birds studied had a high content of docosahexaenoic acid. However brain mitochondria but not microsomes isolated from all the birds analyzed showed a significant decrease of arachidonic and docosahexaenoic acids during lipid peroxidation. The allometric analyses of chemiluminescence were not statistically significant. In conclusion our results show absence of correlation between the sensitivity to lipid peroxidation of brain mitochondria and microsomes with body size and maximum life span.

Removal of the uropygial gland does not affect serum lipids, cholesterol and calcium levels in the rock pigeon Columba livia.

The uropygial gland is an organ typical of birds, over which no agreement regarding its function has been attained yet. Authors attribute to the gland an hydrophobic action. The function of the gland is herein explored in rock pigeon, Columba livia, was used as experimental model for trials. The study was focused on the physiological role of the gland in relation to biochemical parameters. Pigeons were separated in groups of six birds each: a) intact control, b) surgical control, c) ablationed. Comparing control specimens with gland-removed specimens, recorded serum levels after 32 days were the following (mean+/-SD): cholesterol (g/l), 3.7+/-0.6 vs. 4.1+/-0.6; total lipids (g/l), 15.7+/-2.0 vs. 13.7+/-2.7; calcium (mg/l), 100.5 +/- 24.3 vs. 99.1 +/- 9.2. None of the differences were statistically significant. Thus, no alterations of basic biochemical parameters associated with metabolism of lipids were registered. In one group of birds the calcium and cholesterol levels were determined 122 days after surgery; in this case values remained unchanged related to the beginning of the trials. Results suggest that the uropygial gland is not physiologically related to either the homeostasis of total lipids, cholesterol or the regulation of calcium metabolism.

Comparison of first-line antiretroviral therapy with regimens including nevirapine, efavirenz, or both drugs, plus stavudine and lamivudine: a randomised open-label trial, the 2NN Study.

BACKGROUND: The 2NN Study was a randomised comparison of the non-nucleoside reverse-transcriptase inhibitors (NNRTI) nevirapine and efavirenz. METHODS: In this multicentre, open-label, randomised trial, 1216 antiretroviral-therapy-naive patients were assigned nevirapine 400 mg once daily, nevirapine 200 mg twice daily, efavirenz 600 mg once daily, or nevirapine (400 mg) and efavirenz (800 mg) once daily, plus stavudine and lamivudine, for 48 weeks. The primary endpoint was the proportion of patients with treatment failure (less than 1 log(10) decline in plasma HIV-1 RNA in the first 12 weeks or two consecutive measurements of more than 50 copies per mL from week 24 onwards, disease progression [new Centers for Disease Control and Prevention grade C event or death], or change of allocated treatment). Analyses were by intention to treat. FINDINGS: Treatment failure occurred in 96 (43.6%) of 220 patients assigned nevirapine once daily, 169 (43.7%) of 387 assigned nevirapine twice daily, 151 (37.8%) of 400 assigned efavirenz, and 111 (53.1%) of 209 assigned nevirapine plus efavirenz. The difference between nevirapine twice daily and efavirenz was 5.9% (95% CI -0.9 to 12.8). There were no significant differences among the study groups in the proportions with plasma HIV-1 RNA concentrations below 50 copies per mL at week 48 (p=0.193) or the increases in CD4-positive cells (p=0.800). Nevirapine plus efavirenz was associated with the highest frequency of clinical adverse events, and nevirapine once daily with significantly more hepatobiliary laboratory toxicities than efavirenz. Of 25 observed deaths, two were attributed to nevirapine. INTERPRETATION: Antiretroviral therapy with nevirapine or efavirenz showed similar efficacy, so triple-drug regimens with either NNRTI are valid for first-line treatment. There are, however, differences in safety profiles. Combination of nevirapine and efavirenz did not improve efficacy but caused more adverse events.

[A new species of the genus Cameronia Basir (Oxyurida: Thelastomatidae) parasite of Gryllodes laptatae Sauss (Orthoptera: Gryllidae) in Argentina]. / Una nueva especie del género Cameronia Basir (Oxyurida: Thelastomatidae) parásita de Gryllodes laplatae Sauss (Orthoptera: Gryllidae) en Argentina.

Cameronia laplatae n. sp. found in City Bell, Argentina, parasitizing crickets is described and illustrated. The new species is distinguished from other members of the genus Cameronia by the distribution pattern of the genital papillae in the male. It differs from all congeners mainly in having two pairs preanal y two pairs postanal papillae.

Two new rhabditida species (Nematoda: Rhabditidae) parasites of Cyclocephala signaticollis (Coleoptera: Scarabaeidae) in Argentina.

Two different Rhabditida species (Nematoda: Rhabditidae) Parasitorhabditis platidontus n. sp. and Cruznema campestris n. sp. are described and illustrated from the larvae of Cyclocephala signaticollis (Coleoptera: Scarabaeidae) from Buenos Aires province, Argentina. Parasitorhabditis platidontus n. sp. is characterized by having 4 odontoplates in the stoma and the vulva is at 80% of the length of the body. Cruznema campestris n. sp. can be distinguished by the presence of 4 odontoplates and the arrangement of the male genital papillae, 9 pairs, of which 4 are preanal and 5 postanal.

Non-enzymatic lipid peroxidation of microsomes and mitochondria isolated from liver and heart of pigeon and rat.

Studies were carried out to determine the level of ascorbate-Fe2+ dependent lipid peroxidation of mitochondria and microsomes isolated from liver and heart of rat and pigeon. Measurements of chemiluminescence indicate that the lipid peroxidation process was more effective in mitochondria and microsomes from rat liver than in the same organelles obtained from pigeon. In both mitochondria and microsomes from liver of both species a significant decrease of arachidonic acid was observed during peroxidation. The rate C18:2 n6/C20:4 n6 was 4.5 times higher in pigeon than in rat liver. This observation can explain the differences noted when light emission and unsaturation index of both species were analysed. A significant decrease of C18:2 n6 and C20:4 n6 in pigeon liver mitochondria was observed when compared with native organelles whereas in pigeon liver microsomes only C20:4 n6 diminished. In rat liver mitochondria only arachidonic acid C20:4 n6 showed a significant decrease whereas in rat liver microsomes C20:4 n6 and C22:6 n3 decreased significantly. However changes were not observed in the fatty acid profile of mitochondria and microsomes isolated from pigeon heart. In the heart under our peroxidation conditions the fatty acid profile does not appear to be responsible for the different susceptibility to the lipid peroxidation process. The lack of a relationship between fatty acid unsaturation and sensitivity to peroxidation observed in heart suggest that other factor/s may be involved in the protection to lipid peroxidation in microsomes and mitochondria isolated from heart.

Cephalobellus lobulata n. sp. (Oxyurida:Thelastomatidae) A parasite of Neocurtilla claraziana Saussure (Orthoptera: gryllotalpidae) from Argentina.

Cephalobellus lobulata n. sp. (Oxyurida: Thelastomatidae) a parasite of the mole cricket Neocurtilla claraziana Saussure (Orthoptera: Gryllotalpidae) found in Argentina is described and illustrated. It is characterized by a short buccal cavity armed with three teeth, a striated cuticle with the first annule wide with four lobes and the second annule divided in twelve lobes. The male have three pairs of preanal papillae and two pairs of postanal papillae.

Binema bonaerensis n. sp. (Oxyurida: Thelastomatidae) parasite of Neocurtilla claraziana Saussure (Orthoptera: Gryllotalpidae) in Argentina.

The nematode Binema bonaerensis n. sp. (Oxyurida: Thelastomatidae) is described from the intestine of the mole cricket of Neocurtilla claraziana Saussure (Orthoptera: Gryllotalpidae) from Buenos Aires Province, Argentina. It is distinguished mainly by having a conical tail; three sclerotized arches in the buccal cavity; an excretory pore immediately posterior to the base of the esophagus and the presence of five pairs of male genital papillae with one pair preanal and four pairs postanal.

Euryconema brevicauda n. sp. (Oxyurida: Thelastomatidae) a parasite of the mole cricket Neocurtilla claraziana (Orthoptera: Gryllotalpidae) in Argentina.

Euryconema brevicauda n. sp. parasitizing the mole cricket Neocurtilla claraziana found in Buenos Aires province, Argentina, is described and illustrated. This species is characterized by the male having 3 pairs of genital papillae, 1 pair preanal and 2 pairs postanal, and a short, conical-shaped tail.

[Detection of the viral load and its use as a virological marker in the follow-up of HIV-1-positive patients]. / Detección de la carga viral y su uso como marcador virológico en el seguimiento de pacientes HIV-1 positivos.

The evaluation of viral load as virological marker and its clinical and immunological correlation are presented. The first viral load studies were performed during 1996 at the National Reference Center for AIDS in Argentina in HIV-1 positive patients derived from different Hospitals in Buenos Aires. The study included 216 HIV-1 positive patients, 49 females and 167 males. Plasma was used for evaluating viral load and a second sample was obtained in 25 of the 216 patients for their monitoring. Viral load was performed using bDNA technique (Quantiplex HIV RNA assay 2.0, Chiron Corporation, USA). Other parameters such as CD4 count determined by flow cytometry and clinical stages according to CDC classification were obtained in order to correlate clinical and immunological status of the patients. When CD4 count was compared with viral load, the results showed a trend of viral RNA increase in plasma along with a decrease in CD4+ lymphocytes. This trend was also observed to correlate with the progression to AIDS disease. In all groups of patients, considering either CD4 counts or clinical status, ranges of viral load values were broad. Thus, as shown by percentiles 25 and 75, patients with CD4 counts < 200/ml, presented viral load values between 18,395 c/ml to 215,425 c/ml and patients with > 200/ml viral RNA showed values from < 10,000 to 35,180 c/ml. Patients with CDC's A and B stages presented values from < 10,000 to 45,160 c/ml and 87,000 c/ml respectively, while patients classified as C had 10,582 to 215,000 c/ml. Results of two consecutive samples in the 25 patients showed the usefulness of this technique for monitoring antiretroviral therapy. Nevertheless, despite the tendency of viral load to increase along with the progression of the disease, the broad range of values suggested the importance of using both virological and immunological parameters for the management of HIV infected patients.

Detección de la carga viral y su uso como marcador virológico en el seguimiento de pacientes HIV-1 positivos / Viral load detection and its role as virological marker for the monitoring of HIV-1 positive patients

Se realizaron los primeros estudios de carga viral en pacientes HIV-1 positivos provenientes de diferentes instituciones asistenciales de la Ciudad de Buenos Aires. Se evaluó la carga viral como marcador virológico y su correlación con la clínica y el recuento de los linfocitos CD4+ para 216 pacientes HIV-1 positivos. La técnica utilizada fue bDNA (Quantiplex HIV RNA 2.0 assay, Chiron Corporation). Se observó una tendencia al aumento de la carga viral en los pacientes con menor cantidad de linfocitos CD4+ y en los estadíos clínicos con sintomatología. En pacientes que no recibieron ninguna terapia antirretroviral se encontraron valores desde < 10000 copias de ARN viral/ml de plasma hasta 48995 c/ml. En aquéllos que recibieron terapia antirretroviral se observó mayor variación en los valores de la carga viral como lo mostró un rango de < 10000 c/ml hasta 96605 c/ml. Se obtuvieron muestras consecutivas en 25 pacientes y se observaron diferencias entre ambas muestras que permitieron corroborar la utilidad de la técnica en el seguimiento de los pacientes infectados con HIV (AU)

Detección de la carga viral y su uso como marcador virológico en el seguimiento de pacientes HIV-1 positivos / Viral load detection and its role as virological marker for the monitoring of HIV-1 positive patients

Se realizaron los primeros estudios de carga viral en pacientes HIV-1 positivos provenientes de diferentes instituciones asistenciales de la Ciudad de Buenos Aires. Se evaluó la carga viral como marcador virológico y su correlación con la clínica y el recuento de los linfocitos CD4+ para 216 pacientes HIV-1 positivos. La técnica utilizada fue bDNA (Quantiplex HIV RNA 2.0 assay, Chiron Corporation). Se observó una tendencia al aumento de la carga viral en los pacientes con menor cantidad de linfocitos CD4+ y en los estadíos clínicos con sintomatología. En pacientes que no recibieron ninguna terapia antirretroviral se encontraron valores desde < 10000 copias de ARN viral/ml de plasma hasta 48995 c/ml. En aquéllos que recibieron terapia antirretroviral se observó mayor variación en los valores de la carga viral como lo mostró un rango de < 10000 c/ml hasta 96605 c/ml. Se obtuvieron muestras consecutivas en 25 pacientes y se observaron diferencias entre ambas muestras que permitieron corroborar la utilidad de la técnica en el seguimiento de los pacientes infectados con HIV

Two new species of nematodes (Rhabditida: Diplogasteridae and Rhabditidae) parasites of Gryllodes laplatae (Orthoptera: Gryllidae) in Argentina.

Cephalobium magdalensis n. sp. (Rhabditida: Diplogasteridae) found in Magdalena, Buenos Aires, and Cruznema lincolnensis n. sp. (Rhabditida: Rhabditidae) found in Lincoln, Buenos Aires, parasitizing the cricket Gryllodes laplatae (Orthoptera: Gryllidae) are described and illustrated. C. magdalensis n. sp. is characterized by having the excretory pore between the pseudobulb and the basal bulb and seven pairs of postanal papillae in the male. C. lincolnensis n. sp. can be distiguished by having meanly two pairs of preanal papillae, one pair of adanal papillae and six pairs of postanal papillae in the male.

Rheumatic manifestations in populations at risk for HIV infection: the added effect of HIV.

We assessed the frequency and variability of rheumatologic manifestations in 2 populations with similar risk factors for human immunodeficiency virus (HIV) infection, of which only one was affected. We studied 2 populations at risk for HIV infection (homosexual and intravenous drug users). Group A: 89 individuals carried the virus; and Group B: 80 individuals were HIV negative. In Group A (HIV+) 66.1% had rheumatic manifestations including arthralgias, Reiter's syndrome, arthritis, enthesitis, psoriatic arthritis, Sjögren's syndrome, myopathy, septic arthritis, and lupus-like illness. In contrast, in Group B (HIV-) only 2 had arthralgias, 2 Reiter's syndrome, and 1 rheumatoid arthritis. In summary, rheumatic complaints are common in patients with HIV, and HIV positivity confers an increased susceptibility in populations with similar risk factors for HIV infection.