Isolated diaphragm weakness and the diagnostic value of phrenic nerve stimulation

Acute onset, atraumatic, bilateral diaphragm paralysis due to isolated bilateral phrenic neuropathy is uncommon. Respiratory physicians should be alert to this disorder because it is associated with considerable morbidity and diagnosis is often delayed. These case reports highlight important aspects of the presentation, investigations and management of this disorder

School performance in Australia: is there a role for quasi-markets?

Recent changes to the organisation of Australia's education system have raised the possibility of implementing wide-ranging market reforms. In this article we discuss the scope for introducing reforms similar to the United Kingdom's 'quasi-market' model. We discuss the role of school league tables in providing signals and incentives in a quasi-market. Specifically, we compare a range of unadjusted and model-based league tables of primary school performance in Queensland's public education system. These comparisons indicate that model-based tables which account for socio-economic status and student intake quality vary significantly from the unadjusted tables

Enraizamiento y aclimatización de plantas transgénicas de papaya var. Maradol roja

The disease caused by Papaya ringspot virus is the most important in papaya worldwide. The use of biotechnological techniques, as auxiliary tools, has facilitated the genetic improvement in papaya. Nevertheless, this species has a lot of constraints, mainly during rooting and acclimatization phases. For that reason we developed the present work. The in vitro and ex vitro rooting was evaluated. Culture media with different concentrations of indol-3-butiric acid hormone were used in the in vitro rooting. The influence of Trichoderma harzianum bioproduct in the acclimatization of plants was also studied. The in vitro rooting of transgenic plants was achieved by applying 2 mg.l-1 of indol-3-butiric acid in the culture medium. The ex vitro rooting with high percentages of plants survival was also obtained. The applications of T. harzianum bioproduct on the substrate, previous to the plantation, demonstrated its stimulating effect.Key words: Carica papaya, ex vitro, in vitro, Trichoderma harzianumLa enfermedad causada por el Virus de la mancha anular de la papaya es la más importante del cultivo de la papaya en el mundo. El empleo de las técnicas biotecnológicas, como herramienta auxiliar, ha contribuido al mejoramiento genético en este cultivo, aunque tiene dificultades durante las fases de enraizamiento y aclimatización. Tomando como base estas problemáticas se desarrolló el presente trabajo con el objetivo de lograr el enraizamiento y aclimatización de líneas transformadas de papaya. Se determinó la influencia de dos medios de cultivo con diferentes concentraciones de ácido indol-3-butírico (AIB) sobre el enraizamiento in vitro y ex vitro de plantas de papaya transformadas. Además, se valoró la influencia de la aplicación del biopreparado de Trichoderma harzianum en su aclimatización. Se logró el enraizamiento in vitro de plantas de papaya transgénicas al utilizar 2 mg.l-1 de ácido indol-3-butírico en el medio de cultivo, así como el enraizamiento ex vitro con altos porcentajes de supervivencia. Se demostró la factibilidad de la aplicación del biopreparado de T. harzianum al sustrato, previo a la plantación, por su efecto estimulante.Palabras clave: Carica papaya, ex vitro, in vitro, Trichoderma harzianu

Nuevo explante para la embriogénesis somática en Sorghum bicolor (L.) Mohen

This work was carried out with the objective to form somatic embryos of sorghum, cv. ‘CIAP 132R-05’ starting from callus obtained from sections of in vitro shoots. For the formation of callus, different concentrations of 2,4-D were studied as well as three concentrations of ascorbic acid to eliminate the phenolic oxidation. To increase the percentage of callus formation with embryogenic structures, different segments of the shoots were used. For the formation of somatic embryos, different concentrations of 2,4-D; 6-BAP and L-Proline were added to the culture media. The greatest callus formation (50%) was obtained in the culture medium with 18.1 µM of 2,4-D. When 50 mg l -1  of ascorbic acid was added to the culture medium, the percentage of callus formation increased to 67.5%, and was couple with absence of oxidation of the medium and the explant. The frequency of callus formation with embryogenic structures increased to 95% with the use of segment 1 of the shoot sections in vitro as explant. The greatest number of somatic embryos per callus was obtained when 2,4-D was reduced to 4.52 µM, combined with 22.2 µM of 6-BAP and 500 mg l -1  of L-Proline (41.88). Histological analysis confirmed that structures formed in callus came from a somatic embryogenesis process. For the first time, the efficient formation of somatic embryos of sorghum section 1 of in vitro shoots in vitro was obtained.Keywords: 2,4-D, shoots in vitro, callus, somatic embryosEl trabajo fue realizado con el objetivo de formar embriones somáticos de sorgo, variedad ‘CIAP 132R-05’ a partir de callos obtenidos de secciones de brotes in vitro. En la formación de callos fueron estudiadas diferentes concentraciones de 2,4 D y tres concentraciones de ácido ascórbico para eliminar la oxidación fenólica. Para incrementar el porcentaje de formación de callos con estructuras embriogénicas fueron empleados diferentes segmentos de brote. Se añadieron diferentes concentraciones de 2,4-D, 6-BAP y L- prolina al medio de cultivo para la formación de embriones somáticos. La mayor formación de callos (50%) se obtuvo en el medio de cultivo con 18.1 µM de 2,4-D. Cuando se añadieron 50 mg l -1  de ácido ascórbico al medio de cultivo, el porcentaje de formación de callos se incrementó en 67.5%, unido a la ausencia de pigmentos fenólicos en el explante. La frecuencia de formación de callos con estructuras embriogénicas aumento hasta 95% con el uso del segmento 1 como explante. El mayor número de embriones somáticos por callos se obtuvo cuando 2,4-D fue reducido a 4.52 µM, combinado con 2.22 µM de 6-BAP y 500 mg l -1  de L-prolina (41.88). El análisis histológico confirmó que las estructuras formadas a partir de los callos provienen del proceso de embriogénesis somática. Por vez primera se obtuvo la formación eficiente de embriones somáticos de sorgo de a partir de la seccion 1 de brotes in vitro.Palabras clave: 2,4-D, brotes in vitro, callos, embriones somático

Alcohol enhances economic demand for nicotine in rats selectively bred for alcohol preference.

Rationale. Alcohol use disorders (AUDs) and tobacco dependence are frequently identified as co-morbid. Although less than 20% of the general population smokes, over 80% of people with AUDs are considered daily smokers. In fact, people with AUDs are more likely to die from smoking-related health issues, than from alcohol related health issues. Surprisingly, there is very little evidence that alcohol and nicotine are concurrently self-administered in pre-clinical models. We hypothesized that low doses of nicotine that enhancing responding for other rewards would be self-administered and enhance self-administration of alcohol. Objective. The goal of this study was to determine if low-doses of nicotine, typically not self-administered alone, would promote alcohol self-administration in a concurrent access paradigm. Method. Alcohol preferring rats (females) were requested from the University of Indiana Medical School breeding facility. They were randomly assigned to one of three groups – NIC-Alone, ALC-Alone, or ALC+NIC. All rats were fluid restricted and shaped to lick for water at two sipper tubes that could record lick responses and deliver aliquiots of fluid into the sipper tube via a solenoid valve. After shaping, rats were instrumented for IV self-administration. During self-administration tests, rats in the ALC-Alone received access to oral ethanol (15% v/v) for meeting the schedule of reinforcement at one sipper tube (e.g., right) and saline infusions for meeting the schedule of reinforcement at the other sipper tube (e.g., left). The NIC-Alone group received IV nicotine infusions (15 ug/kg/inf) and oral licorice (1%) for meeting the schedule of reinforcement at one sipper tube (e.g., left) and oral water for meeting the schedule of reinforcement at the other sipper tube (e.g., right). The ALC+NIC group received IV nicotine and oral licorice for meeting the schedule of reinforcement on the left sipper, and oral ethanol for meeting the schedule of reinforcement on the right sipper. Price manipulations for nicotine were performed by adjusting the schedule of reinforcement on the sipper associated with nicotine infusions. Results. During acquisition, nicotine did not enhance alcohol self-administration – alcohol intake was comparable between ALC-Alone and ALC+NIC rats. In addition, alcohol did not enhance nicotine self-administration as responding for NIC was comparable between ALC+NIC and NIC-Alone rats. However, when the price of nicotine was manipulated, alcohol created a greater demand for nicotine, as indicated by higher rates of nicotine consumption with increases in price. Manipulating the price of nicotine did not alter demand for alcohol. Conclusion. The interaction between alcohol and nicotine reinforcers may depend on changes in demand for nicotine. Future studies should investigate whether demand for alcohol is altered by concurrently available nicotine infusions. *the first and second authors contributed equally to this projec

Nicotine-enhanced sign tracking results in greater cocaine demand in rats using a behavior economic analysis approach.

Rationale. Nicotine is often considered a ‘gateway’ drug because people typically experiment with tobacco before illicit drugs such as cocaine and amphetamine. We have shown that nicotine increases approach to reward-associated stimuli, this is referred to as ‘sign-tracking’, and that this effect persists after nicotine is discontinued. Individuals who are high in sign-tracking also show increased cocaine self-administration. Objectives. The goal of this experiment was to determine whether nicotine enhanced sign tracking could result in greater cocaine self-administration. Method. Rats were randomly assigned to one of 2 groups (NIC or SAL), and injected with their assigned solution (0.4 mg/kg base or placebo, respectively) 15 min before conditioning sessions. During conditioning sessions, a lever/light stimulus was inserted into the chamber for 15 s and immediately followed by sucrose delivery. Approach to the sucrose receptacle was recorded by monitoring head entries and defined as goal tracking. Contact with the lever was recorded and defined as ‘sign-tracking’. After 29 conditioning sessions, the rats were instrumented for cocaine self-administration and were shaped to respond for cocaine on the same lever that served as the CS. After 10 days of acquisition of cocaine self-administration (0.16 mg/inf), demand for cocaine was tested over 6 days using a within session procedure that increased cocaine price every 10 min. Results. We showed increased sign-tracking, but not goal tracking in the NIC group relative to the SAL group. The NIC group also showed increased demand for cocaine during the price manipulation, but the essential value of cocaine did not differ, relative to the SAL group. Conclusion. Our results support a gateway interpretation of substance use – when both the gateway drug (nicotine) and drug-associated rewards (the lever/light) occur together, they can promote future self-administration of illicit drugs such as cocaine