Transfection of pulmonary cells by stable pDNA-polycationic hybrid nanostructured particles

AIM

Cationically modified solid lipid nanoparticles (SLN) were investigated as plasmid DNA (pDNA) carriers and transfection agents for the pulmonary route.

MATERIALS & METHODS

pDNA-loaded SLN were produced using glyceryl dibehenate or tristearate as matrix lipids and chitosan as surface charge modifier, and encapsulated by spray-drying in mannitol and trehalose microspheres.

RESULTS

Nanoparticles of 200 nm, and zeta potential around +15 mV were produced. Electrophorectic analysis confirmed plasmid stability and integrity. The pDNA-loaded SLN were able to transfect the Calu-3 and A549 pulmonary cell lines, while showing low cytotoxicity. Microencapsulation of SLN yielded dry powders suitable for inhalation that protected pDNA from degradation.

CONCLUSION

Microencapsulated SLN are a promising safe and effective carrier system for pulmonary gene delivery following pulmonary administration.

Maternal separation impairs long term-potentiation in CA1-CA3 synapses and hippocampal-dependent memory in old rats

Exposure to chronic stress during the neonatal period is known to induce permanent long-term changes in the central nervous system and hipothalamic-pituitary-adrenal axis reactivity that are associated with increased levels of depression, anxiety, and cognitive impairments. In rodents, a validated model of early life stress is the maternal separation (MS) paradigm, which has been shown to have long-term consequences for the pups that span to adulthood. We hypothesized that the early life stress-associated effects could be exacerbated with aging, because it is often accompanied by cognitive decline. Using a MS model in which rat pups were separated from their mothers for 3 hours daily, during postnatal days 2-14, we evaluated the long-term functional consequences to aged animals (70-week-old), by measuring synaptic plasticity and cognitive performance. The baseline behavioral deficits of aged control rats were further exacerbated in MS animals, indicating that early-life stress induces sustained changes in anxiety-like behavior and hippocampal-dependent memory that are maintained much later in life. We then investigated whether these differences are linked to impaired function of hippocampal neurons by recording hippocampal long-term potentiation from Schaffer collaterals/CA1 synapses. The magnitude of the hippocampal long-term potentiation induced by high-frequency stimulation was significantly lower in aged MS animals than in age-matched controls. These results substantiate the hypothesis that the neuronal and endocrine alterations induced by early-life stress are long lasting, and are able to exacerbate the mild age-associated deficits.

The role of predictability in the stress response of a cichlid fish

In recent years there has been an increasing interest in the cognitive abilities of fish with implications for animal welfare and management of rearing operations. Although it is known that psychological factors can modulate the stress response in mammals, this aspect has seldom been investigated within stress in fish. In this study we investigate whether the perception (appraisal) that fish make of significant environmental events modifies their behavioural and physiological response. For this purpose we have used a predictable vs. unpredictable paradigm for positive (feeding) and negative (confinement) events using the cichlid fish Oreochromis mossambicus as a model species. Results show that there is a differential effect of predictability for the feeding and confinement events. In the confinement experiment, predictability involved more attention to the visual cue and lower cortisol. The feeding event triggered higher levels of anticipatory behaviour and a tendency for higher cortisol in the predictable group. Therefore, predictable negative events reduce the cortisol response. Predictable positive events may elicit an anticipatory response, and when there is a significant delay between the visual cue and the actual occurrence of the event, it may also contain elements that can be interpreted as a stress response. These findings demonstrate that fish can appraise relevant aspects of the environment, with welfare implications for housing, husbandry and experimental procedures.

Hydrolysis of sucrose using sulfonated poly(vinyl alcohol) as catalyst

The hydrolysis of sucrose was carried out over poly(vinyl alcohol) (PVA) with sulfonic acid groups, at 80 degrees C. The products of sucrose hydrolysis were glucose and fructose. A series of PVA with different crosslinking degree were prepared. It was observed that the catalytic activity of PVA matrix increases with the crosslinking degree, due to the increases of the amount of sulfonic acid groups on PVA. Further, the influence of various reaction parameters, such as, catalyst loading, initial concentration of sucrose and temperature, on the hydrolysis of sucrose over PVA_40 was studied. It was found that at 80 degrees C, with 0.511 g of catalyst loading and with an initial concentration of sucrose of 0.6M, a sucrose conversion of about 90%, after 3h, could be obtained. The PVA_40 catalyst was recycled and reused with negligible loss in the activity. A simple kinetic model was developed assuming that the sucrose hydrolysis is an irreversible reaction and the first order with respect to the sucrose concentration. Since the concentration profiles of the reactant and the products do not exhibit any pronounced initial inductive period, the external and internal diffusion of the reactant and products on the catalyst were not considered. It was observed that the kinetic model fits experimental concentration data quite well.

Sinonasal hemangiopericytoma of the middle turbinate: a case report and brief review of the literature

Hemangiopericytomas (HPCs) are rare vascular neoplasms that arise from the pericytes of Zimmerman. They account for 2-3% of all soft tissue sarcomas in humans and they occur mainly in the musculoskeletal system. 15 to 30% of all HPCs occur in the head and neck region. Only 5% are located in the sinonasal region, where they display a more benign behaviour than in other parts of the body. We will describe a case of a right-sided HPC, in the posterior third of the middle turbinate. We will also discuss the epidemiology, the macro- and microscopical characteristics, the clinical and pathological findings and the treatment of this particular neoplasia.

[Postoperative compressive spinal epidural hematomas. 15 cases and a review of the literature]

PURPOSE OF THE STUDY

In the literature, the frequency of postoperative compressive spinal epidural hematomas (SEH) appearing very low, we conducted the present study to determine the frequency of this complication in their unit and look for causative and predisposing factors.

MATERIAL AND METHODS

Among the 1,487 spinal operations performed in our unit between September 1997 and August 1998, fifteen patients had postoperative compressive SEH; their files were retrospectively analyzed regarding the initial intervention, postoperative period, revision operation and neurologic follow-up.

RESULTS

Five women and ten men were involved ranging in age from 47 to 70 years (average, 59.5 years). The primary intervention concerned the cervical spine in one case, the thoracic spine in seven and the lumbar spine in seven. Ten of the fifteen cases including all seven of the thoracic SEH (performed for compressive metastatic epiduritis) involved a laminectomy. A stenotic canal was the indication for the primary intervention in six of the seven lumbar cases. The average delay before onset of symptoms was 1.5 hours, 3.7 hours, and 5.3 hours after the cervical, thoracic, and lumbar interventions, respectively. The clinical pattern began with segmental pain rapidly followed first by bilateral radicular sensory deficit, then unilateral or bilateral motor deficit, except in the patients with thoracic SEH in whom segmental pain was followed by signs of cord impingement. Excluding the four cases in which diagnosis was retarded by work-up examinations (3 cases) or a misleading picture (1 case), revision surgery was performed from 1.25 to 4 hours after onset of symptoms (average, 2.75 hours). In the patients for whom reoperation was delayed, SEH resulted in permanent complete paralysis or sphincter dysfunction. In contrast, eight of the ten patients who were reoperated within four hours of the onset of symptoms either recovered completely or recovered their former neurologic status.

DISCUSSION

Compressive SEH after spinal surgery is rare, only 41 cases having been reported aside from the series of Deburge et al. In the literature, the frequency is around 1 to 2 for 1000 operations for some authors, as opposed to 3 p. 100 and 6 p. 100 found by two other groups. The 1 p. 100 of the present series is close to the latter values. Nonetheless, it is probably important to take the type of surgery into account, as shown by the current series in which SEH occurred after 5.9 p. 100 of the operations for metastasis, but only once out of 304 anterior cervical interventions. To reduce the risk as much as possible, it is important to be aware of the factors that may contribute to this complication. Several recommendations concerning prevention of SEH are thus discussed. Once SEH has occurred, the only modifiable prognostic factor appears to be the delay before reintervention.

CONCLUSION

Although postoperative SEH is relatively rare, it may have dramatic consequences. In our opinion, reintervention must be performed as soon as possible after the onset of neurologic deficit, the work-up investigations only prolonging the critical surgical delay, which is probably the only alterable prognostic factor.