Nonmedical costs associated with rotavirus disease requiring hospitalization

BACKGROUND: As the most common cause of severe diarrhea among children, rotavirus has a significant economic impact. Previous studies focused on the direct medical costs of rotavirus infections; however, nonmedical costs account for the majority of the financial burden from this disease. Herein, we report the results from the largest prospective study in the United States determining the nonmedical costs of severe rotavirus infections. METHODS: Prospective, active, gastroenteritis case surveillance was conducted between November 1997 and December 1999 at 3 pediatric medical centers. Rotavirus infection was identified for 548 children admitted between 2 weeks and 5 years of age. Detailed information about nonmedical costs during the prehospitalization, hospitalization and posthospitalization periods was obtained through interviews. RESULTS: The average nonmedical cost per case of rotavirus disease was USD $448.77, including $359.04 for missed work, $56.66 for transportation, $11.90 for oral rehydration solutions, $9.59 for diapers, $6.83 for child care changes, $3.82 for special foods and $0.93 for formula changes. More than one-half of these expenses (53%) occurred outside the hospitalization period, and 80% of the cost was attributable to missed work. CONCLUSIONS: With an estimated 50,000 hospitalizations attributable to rotavirus each year in the United States, the nonmedical costs of severe rotavirus infections may exceed USD $22 million annually. Previous cost effectiveness analyses of rotavirus vaccines substantially underestimated this burden, suggesting that the nonmedical costs associated with mild to moderate rotavirus disease have been similarly underestimated. These findings are needed to assess accurately the cost effectiveness of future rotavirus immunization strategies.     

The role of PAF, TLR, and the inflammatory response in neonatal necrotizing enterocolitis

The pathogenesis of neonatal necrotizing enterocolitis remains poorly understood. Recent evidence suggests that PAF (platelet activating factor) and human toll-like receptors (TLRs) contribute to the pro-inflammatory response that is characteristic of NEC pathology. Understanding the regulation of these molecular interactions may provide new approaches for prevention or treatment of this dreaded condition.     

A novel growth hormone secretagogue-1a receptor antagonist that blocks ghrelin-induced growth hormone secretion but induces increased body weight gain

Ghrelin, the natural ligand for the growth hormone secretagogue-1a (GHS-1a) receptor, has received a great deal of attention due to its ability to stimulate weight gain and the hope that an antagonist of the GHS-1a receptor could be a treatment for obesity. We have discovered an analog of full-length human ghrelin, BIM-28163, which fully antagonizes GHS-1a by binding to but not activating the receptor. We further demonstrate that BIM-28163 blocks ghrelin activation of the GHS-1a receptor, and inhibits ghrelin-induced GH secretion in vivo. Unexpectedly, however, BIM-28163 acts as an agonist with regard to stimulating weight gain. These results may suggest the presence of an unknown ghrelin receptor that modulates ghrelin actions on weight gain. In keeping with our results on growth hormone (GH) secretion, BIM-28163 acts as an antagonist of ghrelin-induced Fos protein immunoreactivity (Fos-IR) in the medial arcuate nucleus, an area involved in the ghrelin modulation of GH secretion. However, in the dorsal medial hypothalamus (DMH), a region associated with regulation of food intake, both ghrelin and BIM-28163 act as agonists to upregulate Fos-IR. The observation that ghrelin and BIM-28163 have different efficacies in inducing Fos-IR in the DMH, and that concomitant administration of ghrelin and an excess of BIM-28163 results in the same level of Fos-IR as BIM-28163 administered alone may demonstrate that in the DMH both ghrelin and BIM-28163 act via the same receptor. If so, it is unlikely that this receptor is GHS-1a. Collectively, our findings suggest that the action of ghrelin to stimulate increased weight gain may be mediated by a novel receptor other than GHS-1a, and further imply that GHS-1a may not be the appropriate target for anti-obesity strategies.     

Lighting the chandelier: new vistas for axo-axonic cells

Chandelier or axo-axonic cells are the most selective of all cortical GABAergic interneurons, because they exclusively contact axon initial segments of cortical glutamatergic neurons. Owing to their privileged location on initial segments, axo-axonic cells have often been assumed to have the ultimate control of pyramidal cell output. Recently, key molecules expressed at the initial-segment synapses have been identified, and novel in vitro and in vivo electrophysiological studies have revealed unexpectedly versatile functional effects exerted by axo-axonic cells on their postsynaptic targets. In addition, there is also emerging recognition of the mechanistic involvement of these unique cells in several neurological diseases, including epilepsy and schizophrenia.     

Galnon--a low-molecular weight ligand of the galanin receptors

Galnon is a low-molecular weight galanin receptor ligand, with affinity towards the three galanin receptors in the micromolar range. Galnon is of interest as a drug candidate due to its stability and ability to pass the blood-brain barrier. Like galanin, galnon has also been shown to affect various physiological functions; however, occasionally galanin and galnon act in opposing ways. Since its introduction in 2002, galnon has been characterized to inhibit seizures, decrease feeding behaviour, diminish physical signs of opiate withdrawal and to alleviate heat-hyperalgesic response to partial sciatic nerve injury. In this review, we will summarize what is known about galnon to date.     

Age-related impairments of synaptic plasticity in the lateral perforant path input to the dentate gyrus of galanin overexpressing mice

In the present study, electrophysiological recordings were made from hippocampal slices obtained from mice overexpressing galanin under the promoter for the platelet-derived growth factor-B (GalOE mice). In these mice, a particularly strong galanin expression is seen in the granule cell layer/mossy fibers. Paired-pulse facilitation (PPF) of excitatory postsynaptic field potentials (fEPSPs) at the lateral perforant path (LPP)-dentate gyrus synapses was elicited in the dentate gyrus after stimulation with different interpulse intervals. Slices from young adult wild-type (WT) animals showed significant PPF of the 2nd EPSP evoked with paired-pulse stimuli, while PPF was reduced in slices from young adult GalOE mice, as well as aged WT mice, but were not observed at all in slices from aged GalOE animals. Application of the putative galanin antagonist M35 increased PPF in slices from aged WT mice as well as from adult and aged GalOE mice, but had no effect in slices taken from young adult WT mice. These data indicate that galanin is involved in hippocampal synaptic plasticity, in particular in age-related reduction of synaptic plasticity in the LPP input to the dentate gyrus. Galaninergic mechanisms may therefore represent therapeutic targets for treatment of age-related memory deficits and Alzheimer's disease.     

Homodimerization and internalization of galanin type 1 receptor in living CHO cells

Galanin is a 29- to 30-aa-long neuropeptide affecting feeding, cognitive, and sexual behavior. It exerts its effects through galanin receptors 1, 2 and 3, which are all seven transmembrane domain G-protein coupled receptors (GPCRs). The GPCRs have been shown to function as monomers, homodimers, heterodimers and oligomers. In this study, we examined the extent of galanin receptor 1 (GalR1) dimerization and internalization in living CHO cells using fluorescence resonance energy transfer (FRET) and time lapse confocal imaging. Ratio imaging analysis and emission spectral analysis revealed substantial homodimerization of GalR1. In addition, internalization of GalR1 after 1h of agonist stimulation with the GalR1 agonist galanin (1-29) was observed with time lapse fluorescence imaging, whereas stimulation with the GalR2 specific agonist galanin (2-11) did not lead to internalization. Treatment of GalR1 transfected cells with the non-selective adenylyl cyclase activator forskolin influenced the rate of internalization when administered together with galanin (1-29). These results indicate that GalR1 can act as a dimer on the cell surface and that receptor desensitization and internalization was observed after stimulation with the agonist galanin (1-29). Western blots further confirm the FRET data that GalR1-XFP dimerizes and can be detected in the cell as a monomer or dimer using antibodies to XFP. Internalization and dimerization of GalR1 is shown, contributing to the regulation of galanergic signaling.     

Multiple interaction sites of galnon trigger its biological effects

Galnon was first reported as a low molecular weight non-peptide agonist at galanin receptors [Saar et al. (2002) Proc. Natl. Acad. Sci. USA 99, 7136-7141]. Following its systemic administration, this synthetic ligand affected a range of important physiological processes including appetite, seizures and pain. Physiological activity of galnon could not be explained solely by the activation of the three known galanin receptors, GalR1, GalR2 and GalR3. Consequently, it was possible that galnon generates its manifold effects by interacting with other signaling pathway components, in addition to via GalR1-3. In this report, we establish that galnon: (i) can penetrate across the plasma membrane of cells, (ii) can activate intracellular G-proteins directly independent of receptor activation thereby triggering downstream signaling, (iii) demonstrates selectivity for different G-proteins, and (iiii) is a ligand to other G-protein coupled receptors (GPCRs) in addition to via GalR1-3. We conclude that galnon has multiple sites of interaction within the GPCR signaling cascade which mediate its physiological effects.     

Low CA1 spine synapse density is further reduced by castration in male non-human primates

The hippocampus plays a major role in learning and memory and its morphology and function are readily affected by gonadal hormones in female non-human primates. We sought to determine whether the gonads also affect pyramidal cell spine synapse density in the CA1 hippocampal area of male primates. Unbiased electron microscopic stereological calculations were performed to determine the volumetric density of pyramidal cell spine synapses and semiquantitative analyses on the surface density of glial fibrillary acidic protein-containing glia processes and the diameter of pyramidal cell apical dendrites in the CA1 area of intact and orchidectomized (1 month) St Kitts vervet monkeys (Chlorocebus aethiops sabaeus). The volumetric density (number of spine synapse/ micro m(3)) of spine synapses was significantly lower (40%) in the gonadectomized animals than in control monkeys; conversely, the density of glia processes was significantly higher (15%) and the diameter of dendritic shafts located in this area was also larger (30%) in the orchidectomized animals than in the controls. Strikingly, when compared to female values, intact male primates had lower spine synapse densities than either intact or ovariectomized females. Since the primate hippocampus is very similar to that of a human's, the present observations suggest that physiological levels of circulating androgen hormones are necessary to support normal spine synapse density in the CA1 stratum radiatum of human male hippocampus.