Predictive power of Markovian models: Evidence from US recession forecasting

This paper provides extensions to the application of Markovian models in predicting US recessions. The proposed Markovian models, including the hidden Markov and Markov models, incorporate the temporal autocorrelation of binary recession indicators in a traditional but natural way. Considering interest rates and spreads, stock prices, monetary aggregates, and output as the candidate predictors, we examine the out‐of‐sample performance of the Markovian models in predicting the recessions 1–12 months ahead, through rolling window experiments as well as experiments based on the fixed full training set. Our study shows that the Markovian models are superior to the probit models in detecting a recession and capturing the recession duration. But sometimes the rolling window method may affect the models' prediction reliability as it could incorporate the economy's unsystematic adjustments and erratic shocks into the forecast. In addition, the interest rate spreads and output are the most efficient predictor variables in explaining business cycles.     

Evidence for mimicry by viral antigens in animal models of autoimmune disease including myocarditis

Molecular mimicry of viral antigens with self determinants has been proposed as one of the pathogenic mechanisms in autoimmune disease. Evidence of viral mimicry in animal models of autoimmunity is accumulating. Murine adenovirus, Semliki forest virus, lactate dehydrogenase-elevating virus, herpes simplex virus type-1, hepatitis B virus, encephalomyocarditis virus, Theiler's murine encephalomyelitis virus, Coxsackievirus and cytomegalovirus have been found to mimic physiologically important host proteins. However, epitope homology of a viral and self determinant is not in itself strong evidence for mimicry as a pathogenic mechanism. The mimicking determinant must also be capable of inducing disease in the absence of replicative virus. Animal models provide evaluation of the viral trigger, and development and therapy for autoimmune diseases. Identification of host proteins that can induce disease together with the knowledge of immune system dysregulation, genetic association and environmental factors may lead to improved immunotherapeutic strategies for human autoimmune diseases.     

Endothelial dysfunction in the klotho mouse and downregulation of klotho gene expression in various animal models of vascular and metabolic diseases

The human aging process is associated with vascular endothelial dysfunction. However, humoral factors which might protect against endothelial dysfunction during aging have not yet been identified. We recently identified the klotho gene as a possible regulator of human aging. In the present study using the klotho-deficient heterozygous mouse, we examined whether the Klotho protein is a humoral factor protecting against endothelial dysfunction. We further cloned rat klotho cDNA and investigated whether klotho mRNA expression in rat kidney is altered under pathological conditions such as hypertension, hyperlipidemia, renal failure, and inflammatory stress. The Klotho protein itself, or its metabolites, promotes endothelial NO production in aorta as well as arterioles, and klotho mRNA in kidney is downregulated under sustained circulatory stress.     

Nucleolar alterations of peripheral nerve cells in rats following administration of 4-hydroxy-aminoquinoline 1-oxide

Zusammenfassung Durch i.v. Injektion der besonders carcinogenen Substanz 4-Hydroxyaminochinolin 1-Oxid kam es bei Ratten zu nukleolären Veränderungen der peripheren Nervenzellen.     

Evidence for enzymatic reduction of 1-nitropyrene by rat liver fractions

Summary 1-Nitropyrene, a mutagenic compound found in diesel exhaust and photocopy toners, is reduced anaerobically by rat liver fractions to 1-aminopyrene. This reaction is stimulated in the microsomal fraction by NADPH and in the cytosol by FMN. Addition of both cofactors produced more reduction in S-9, microsomes, or cytosol than either cofactor alone.     

Evidence for suppression of immune function by insulin-like growth factor-1 in dwarf rats in vivo

These studies were undertaken to investigate the effects of increasing or decreasing IGF-1 levels on aspects of immune function in rats. Female dwarf rats were treated with recombinant human IGF-1 or with a potent sheep anti-IGF-serum. Body weight, thymus weight and spleen weight increased with IGF-1 treatment (p<0.001), while there was no effect of anti-IGF-1 treatment when compared with the appropriate normal sheep serum (NSS) treated controls. IGF-1 treatment significantly decreased WBC and RBC counts, but increased the ratio of CD4⁺:CD8⁺ T-cells. Anti-IGF-1 serum had no effect on these parameters compared with NSS. However anti-IGF-1 was associated with increased T-cell numbers, decreased natural killer cells, and enhancement of the animals' ability to produce specific IgG in response to injection of keyhole limpet haemocyanin (KLH). These results indicate that IGF-1 may suppress immune function although increasing the size of immune organs such as spleen.These studies were part of an M.Sc. at the University of Waikato, Hamilton, New Zealand.     

Increased urinary excretion of cyclic nucleotides in X-linked hypophosphatemic (Hyp) mice

Summary Hyp mice, a model for human X-linked hypophosphatemia, had elevated urinary cyclic AMP, cyclic GMP, and magnesium excretion compared to normal mice. The data suggest a renal origin of the urinary cyclic nucleotides. No significant differences in plasma cyclic AMP and cyclic GMP were observed between genotypes.This work was supported in part by research grants from The Kroc Foundation and the NIH, RR-09016.     

Increased urinary excretion of cyclic nucleotides in X-linked hypophosphatemic (Hyp) mice

Hyp mice, a model for human X-linked hypophosphatemia, had elevated urinary cyclic AMP, cyclic GMP, and magnesium excretion compared to normal mice. The data suggest a renal origin of the urinary cyclic nucleotides. No significant differences in plasma cyclic AMP and cyclic GMP were observed between genotypes.     

Inhibition of interleukin-1 beta release from cultured human peripheral blood mononuclear cells by prednisolone

Prednisolone, a water-soluble glucocorticoid hormone, suppressed the secretion of interleukin-1 beta from human peripheral blood mononuclear cells in culture. The prednisolone-induced suppression of the monokine release was dose-related and the half maximal response was observed at 0.1 nM.     

Extraneuronal serotonin accumulation in peripheral arteries of the rat

Accumulations of serotonin (5-HT) and norepinephrine (NE) were compared in control and 6-hydroxydopamine (6-OHDA) pretreated rat aorta, mesenteric and tail arteries. The distribution of these amines was corrected by subtracting tissue uptake of tritiated sorbitol in the extracellular space. 5-HT greatly accumulated both in control and 6-OHDA pretreated arteries. In contrast, NE accumulation in mesenteric and tail arteries was substantially decreased after 6-OHDA treatment. In the aorta 6-OHDA pretreatment did not affect the accumulation of both amines. These findings suggest that 5-HT accumulation in these arteries is mainly extraneuronal, and NE mainly neuronal. Since the accumulation of 5-HT in the aorta was not influenced by pretreatment with 10 microM NE, the extraneuronal uptake mechanisms for 5-HT and NE appear to be different.     

Role of metallothioneins in peripheral nerve function and regeneration

The physiological role of the metallothionein (MT) family of proteins during peripheral nerve injury and regeneration was examined in Mt1+ 2 and Mt3 knockout (KO) mice. To this end, the right sciatic nerve was crushed, and the regeneration distance was evaluated by the pinch test 2-7 days postlesion (dpl) and electrophysiologically at 14 dpl. The quality of the regeneration was assessed by light microscopy and immunohistochemical methods. The results show that the regeneration distance was greater in the Mt3 KO than in the Mt1+ 2 KO mice, whereas control mice showed intermediate values. Moreover, the number of regenerating axons in the distal tibial nerve was significantly higher in Mt3KO mice than in the other two strains at 14 dpl. Immunoreactive profiles to protein gene product 9.5 were present in the epidermis and the sweat glands of the plantar skin of the hindpaw of the Mt3 KO group. The improved regeneration observed with the Mt3 KO mice was confirmed by compound nerve action potentials that were recorded from digital nerves at 14 dpl only in this group. We conclude that Mt3 normally inhibits peripheral nerve regeneration.