Longer Incubation Periods Research Articles

Mineral Concentrations and Rumen Degradability of Biodegraded <i>Enterolobium cyclocarpum</i> (Jacq) and <i>Pterocarpus santalinoides</i> (L’Her) with <i>Aspergillus niger</i>

The effects of solid state fermentation on the mineral concentrations and in sacco degradation characteristics of dry matter in two multipurpose tree leaves was investigated. Biodegraded Enterolobium cyclocarpum (EC) and Pterocarpus santalinoides (PS) leaves were previously inoculated with Aspergillus niger and incubated at 30&degC for five incubation periods (0, 7, 14, 21 and 28 days). After each incubation period, samples were oven dried at 60&degC, allowed to cool and ground for mineral analysis and in sacco dry matter degradability. Three fistulated West African Dwarf (WAD) rams (Ovis aries) were then used for the dry matter degradability. Five grams of each sample was emptied into nylon bag (Polymon, Switzeland) with pore size of 4 μ and effective size of 5 cm × 18 cm and incubated in the rumen of the fistulated animals for 6, 12, 24, 48, 72, and 96 h. The results showed that the mineral contents of biodegraded EC samples were affected by incubation period. Mean values of Ca, Cu, K, Na, and Zn were significantly increased (0.05), while mean values of Fe, Mg, and Mn were first reduced before significantly increasing (0.05). However, the composition of P showed significant reduction (0.05) up to day 28 where no change was observed. Mineral concentrations in biodegraded PS were also affected by incubation periods. Values of Ca, Fe, K, Mg, Mn, Na, and Zn were significantly increased (0.05). However values of Cu, and Fe only increased after day 14, while the value of P was reduced significantly over the different incubation periods. Potential degradability (PD) for biodegraded EC was highest at day 0 (50.79%) but not significantly different from potential degradability of longer incubation periods to day 28 (48.68%). PS had higher PD than EC. In spite of high PD values, PS comparatively degraded faster than EC. Effective degradability (ED) for EC was highest for day28 (36.71%) and not significantly different from days 21 (34.83%) and 7 (35.29%) but significantly different from days 0 (31.32%) and 14 (31.75%) respectively. However, the ED for PS was highest for day 0 (31.39) samples and significantly differed from other incubation periods, further increase in period only showed lower but similar ED values for days 7 (27.52%), 14 (26.76%), 21 (27.42%) and 28 (26.86%) respectively. In this study, the continued reduction in P concentrations in both biodegraded EC and PS suggest that Aspergillus niger has preferential demand for P and in sacco degradation showed increase in PD and ED values for fungal biodegraded EC and reduction in PS, suggesting improved quality of EC.

Visfatin contributes to the differentiation of monocytes into macrophages through the differential regulation of inflammatory cytokines in THP-1 cells

Visfatin is a novel multifunctional adipocytokine with inflammatory properties. Although a link between visfatin and atherosclerosis has recently been suggested, its actions in the development of atherosclerosis remain unknown. Therefore, we investigated a potential role and underlying mechanism(s) of visfatin in monocytes/macrophages differentiation, a critical early step in atherogenesis, using phorbol-12-myristate-13-acetate (PMA)-stimulated THP-1 cell models. The co-incubation of PMA with visfatin-induced CD36 expression with a concomitant increase in the phagocytosis of latex beads compared with PMA alone treatment. Moreover, visfatin markedly increased interleukin (IL)-1β secretion by enhancing IL-1β mRNA stability in a short-term incubation. Visfatin also significantly elevated the secretion of IL-6 as well as IL-1β in a longer incubation period, which was partially suppressed by nuclear factor-κB (NF-κB) inhibitor, BAY11-7082, and c-Jun-N-terminal kinase (JNK) inhibitor, SP600125. Furthermore, silencing IL-1β successfully blocked IL-6 secretion, CD36 expression, and NF-κB activation in response to visfatin. Collectively, these results suggest that visfatin enhances the IL-1β-dependent induction of IL-6 and CD36 via distinct signaling pathways mediated by JNK and NF-κB, respectively, and consequently, leading to the acceleration of monocytes/macrophages differentiation.

Slow wilt: another form of Marchitez in oil palm associated with trypanosomatids in Peru

Another form of Marchitez manifestation affecting oil palm (Elaeis guineensis) has been observed since 2002 in the Alto Huallaga area from Peru. Externally, the disease appears as chlorosis, drying and breaking of the lower leaves, rot in fruit bunches, accumulation and rot of spears. Internally, the meristem presents brown lesions with a yellowish halo around its base. A high proportion (94%) of affected plants showed trypanosomatids in their roots. After follow up asymptomatic plants for 22 months, 85% develop symptoms of slow wilt. After the appearing of the symptoms the affected plants die between 5 and 8 months. Lincus spurcus population present in affected plants was evaluated and 44% were positive for trypanosomatids. In addition, trypanosomatids were observed in wild plants such as Acalypha cuneata, Urera caracasana, Trema micrantha, Cecropia spp., present in areas with incidence of the disease. The chlorosis, the long period of incubation and the time evolution of the disease are different in comparison with sudden wilt, suggesting a new disease manifestation affecting oil palms. The presence of Lincus positive to trypanosomatids leads us to propose an association of these parasites with slow wilt as reported for sudden wilt.

Identical Pathogenesis and Neuropathological Phenotype of Scrapie in Valine, Arginine, Glutamine/Valine, Arginine, Glutamine Sheep Infected Experimentally by the Oral and Conjunctival Routes

The pathogenesis of scrapie in sheep after natural or oral exposure to the infectious agent generally involves the early accumulation of disease-associated prion protein (PrP(d)) in the lymphoreticular system (LRS). This phase is followed by neuroinvasion, for which two routes, ascending neural and haematogenous, have been postulated. The present study reports the use of immunohistochemistry to track the tissue progression of PrP(d) deposition in sheep of a single, highly scrapie-susceptible PrP genotype administered by the oral or conjunctival routes. Regardless of the route of infection, the earliest detection of PrP(d) was in gut- and pharynx-associated LRS tissues. Subsequently, the brain became PrP(d) positive simultaneously with other LRS tissues, but before the spinal cord and peripheral nervous tissues of the enteric, parasympathetic and sympathetic systems. The sites of initial PrP(d) accumulation in the brain were the dorsal motor nucleus of the vagus and the hypothalamus and their related circumventricular organs (the area postrema and the median eminence, respectively). These were the same for both routes of infection. Rapid progression to clinical disease was observed in sheep infected orally or conjunctivally, with definite signs of scrapie recorded at around 6 and 8 months after infection, respectively. Longer incubation periods in sheep infected by the conjunctival route were probably due to them receiving a lower dose than those infected orally. Irrespective of the route of infection, clinically affected sheep showed the same pathological phenotype (PrP(d) profile) and PrP(d) distribution throughout the brain. The identical peripheral and central pathogenesis observed in sheep of both groups suggests early dissemination of the infectious agent in the bloodstream and a common neuroinvasion pathway. The late involvement of the enteric and autonomic nervous system supports a haematogenous route of infection to the brain.

Lack of prion transmission by sexual or parental routes in experimentally infected hamsters

Prion diseases are a group of neurodegenerative disorders affecting humans as well as captive and wild animals. The mechanisms and routes governing the natural spread of prions are not completely understood and several hypotheses have been proposed. In this study, we analyzed the effect of gender in prion incubation period, as well as the possibility of prion transmission by sexual and parental contact using 263K infected hamsters as a model. Our results show that males have significantly longer incubation periods compared with females when exposed to the same quantity of infectious material. Importantly, no evidence of sexual or parental prion transmission was found, even 500 d after sexual contact or birth, respectively. Western blotting and PMCA were unable to detect sub-clinical levels of PrPSc in experimental subjects, suggesting a complete absence of prion transmission by these routes. Our results show that sexual and parental transmission of prions does not occur in this model. It remains to be studied whether this conclusion is valid also for other prion strains and species.

Epidemiological mechanisms of genetic resistance to kuru

Transmissible spongiform encephalopathies (TSEs), such as kuru, are invariably fatal neurodegenerative conditions caused by a malformation of the prion protein. Heterozygosity of codon 129 of the prion protein gene has been associated with increased host resistance to TSEs, although the mechanism by which this resistance is achieved has not been determined. To evaluate the epidemiological mechanism of human resistance to kuru, we developed a model that combines the dynamics of kuru transmission and the population genetics of human resistance. We fitted our model to kuru data from the epidemic that occurred in Papua New Guinea over the last hundred years. To elucidate the epidemiological mechanism of human resistance, we estimated the incubation period and transmission rate of kuru for codon 129 heterozygotes and homozygotes using kuru incidence data and human genotype frequency data from 1957 to 2004. Our results indicate that human resistance arises from a combination of both a longer incubation period and reduced susceptibility to infection. This work provides evidence for balancing selection acting on a human population and the mechanistic basis for the heterozygote resistance to kuru.

Application of cultivating Yuan and clearing blockage method on HIV/AIDS

According to HIV/AIDS being infectious and have a very long period of incubation, leading to immune system weakened and infected easily, we summarized its pathmechanism including Yuan Qi deficiency (vigour deficiency)and constraint (Qi depression,blood stagnancy, phlegm coagulation, poison accumulation), consequently treatment principle were raised--cultivates the Yuan and clear blockage. From viscera and Qi, blood, Yin and Yang perspective, we elaborate corresponding clinical application method and train of thought, that cultivating the Yuan method means tonify Qi firstly which emphasizes on the spleen and the kidney; Clear blockage method contains relieving liver for smooth Qi, invigorating spleen to remove phlem, promoting blood circulation and detoxification. In addition, cultivating the Yuan and clear blockage should cooperate closely based on traditional Chinese medicine diffrentiation, tonify deficiency should not used individually and vice verse.

Quantifying effect of geographic location on epidemiology of Plasmodium vivax malaria.

Recent autochthonous transmission of Plasmodium vivax malaria in previously malaria-free temperate regions has generated renewed interest in the epidemiology of this disease. Accurate estimates of the incubation period and time to relapse are required for effective malaria surveillance; however, this information is currently lacking. By using historical data from experimental human infections with diverse P. vivax strains, survival analysis models were used to obtain quantitative estimates of the incubation period and time to first relapse for P. vivax malaria in broad geographic regions. Results show that Eurasian strains from temperate regions have longer incubation periods, and Western Hemisphere strains from tropical and temperate regions have longer times to relapse compared with Eastern Hemisphere strains. The diversity in these estimates of key epidemiologic parameters for P. vivax supports the need for elucidating local epidemiology to inform clinical follow-up and to build an evidence base toward global elimination of malaria.

Life history variation among geographically close populations of the toad-headed lizard (Phrynocephalus przewalskii): Exploring environmental and physiological associations

Geographic variation in life history traits has been extensively studied along latitudinal and altitudinal clines, but life history variation among geographically close populations has received much less attention. We collected gravid female toad-headed lizards (Phrynocephalus przewalskii) and environmental data from three localities (Alxa Zuoqi, Alxa Youqi, and Shandan) across the Gobi desert in China, to examine among-population differences in reproductive strategies. The precipitation was significantly lower in Alxa Youqi than Alxa Zouqi and Shandan. Food availability was highest in Shandan, lowest in Alxa Zuoqi, with Alxa Youqi in between. Females from Shandan population were larger and produced more and larger eggs than their counterparts from the other two populations. Incubation period also differed among the populations, with the lowest incubation period in Alxa Youqi population, and the longest incubation period in Alxa Zuoqi population. Our data on the physiological mechanisms of incubation period indicated that the shortened incubation period in Alxa Youqi population was due to advanced embryogenesis completed prior to oviposition rather than higher embryonic heart rates during incubation. Therefore, our data support the hypothesis that geographically close populations can show different reproductive strategies if environmental factors vary among these populations.

Prolonged incubation of processed human spermatozoa will increase DNA fragmentation

One of the causes of failure in ART is sperm DNA fragmentation which may be associated with long period of spermatozoa incubation at 37°C. The objective was to evaluate the rate of sperm DNA fragmentation using the sperm chromatin dispersion (SCD) test after swim-up at different time intervals prior to use. In this prospective study, 21 normozoospermic specimens were analysed. The samples were incubated at 37°C after preparation by direct swim-up. DNA fragmentation was assessed at different time intervals (0, 1, 2 and 3h) using SCD test. Spermatozoa with no DNA fragmentation showed large- or medium-sized halos, and sperm cells with DNA fragmentation showed either a small halo or no halo. The rates of normal morphology and progressive motility after sperm processing were 72.33±2.53% and 90±1.02%, respectively. The rate of sperm DNA fragmentation was significantly higher after 2h (8.81±0.93%, P=0.004) and 3h (10.76±0.89%, P<0.0001) of incubation compared to 0h (4.38±0.8%). A positive correlation was found between the incubation time and sperm DNA damage (P<0.0001). Prolonged incubation of prepared normozoospermic samples at 37°C is associated with higher rates of sperm DNA fragmentation. Therefore, sperm samples intended for ART procedures should be used within 2h of incubation at 37°C.

Effect of wetting period on infection of orchid flowers by Alternaria alternata and Curvularia eragrostidis

The effect of different durations of the incubation wetting period on the infection of Dendrobium flowers by two serious pathogens—Alternaria alternata (Fr.) Keissl. 1912 and Curvularia eragrostidis (Henn.) J.A. Mey. 1959—was investigated. Cut orchid flowers of the genus Dendrobium were used for the inoculation. The courses of symptom development and mycelium growth were determined. The results indicate that the infection and the subsequent development of disease on the flowers occur rapidly even if the conditions favourable for pathogen germination on the plant tissues persist for only 2 h. However, the proportion of infected flowers was significantly higher after a longer incubation period (6 h). The mycelium growth of the pathogen was also significantly influenced by the length of the incubation period.

Stellate hairs on leaves of a deciduous shrub Viburnum erosum var. punctatum (Adoxaceae) effectively protect Brevipalpus obovatus (Acari: Tenuipalpidae) eggs from the predator Phytoseius nipponicus (Acari: Phytoseiidae)

The eggs of the herbivorous false spider mite Brevipalpus obovatus Donnadieu have a longer incubation period than those of spider mites and are not protected by webs. Brevipalpus obovatus often lays its eggs in the gaps among the hairs on host leaves. We examined the effects of stellate hairs of Viburnum erosum var. punctatum (VEP) leaves on the survival of B. obovatus eggs. Adult B. obovatus and Phytoseius nipponicus Ehara, a generalist predator, were introduced to VEP leaf disks; each B. obovatus egg was inspected daily until hatching. More eggs (63 vs. 42%) survived on the abaxial surfaces of VEP leaves, where the stellate hairs are more complicated, than on the adaxial surfaces. Predation hazard decreased rapidly with increasing egg age and a substantial portion of the eggs hatched. Phytoseius nipponicus preyed on eggs regardless of egg age when mixed-age eggs were provided. Manipulative experiments with bent stellate hairs showed that the normal hairs reduced the predation risk of B. obovatus eggs by P. nipponicus. Therefore, the predation hazard was considered to decrease since the stellate hairs hindered the search for B. obovatus eggs by the phytoseiid mite.

What is the incubation period for listeriosis?

BackgroundListeriosis is a foodborne infection with a low incidence but a high case fatality rate. Unlike common foodborne diseases, the incubation period can be long. The first incubation periods were documented during a large listeriosis outbreak published in 1987 by Linnan and al. in the New England Journal of Medicine (range: 3 days to 70 days). Data on the incubation period of listeriosis are scarce. Our study aim was to estimate precisely the incubation period of listeriosis using available data since 1987.MethodsWe estimated the incubation period of listeriosis using available published data and data from outbreak investigations carried out by the French National Institute for Public Health Surveillance. We selected cases with an incubation period calculated when a patient had a single exposure to a confirmed food source contaminated by Listeria monocytogenes.ResultsWe identified 37 cases of invasive listeriosis (10 cases with central nervous system involvement (CNS cases), 15 bacteraemia cases and 12 pregnancy-associated cases) and 9 outbreaks with gastroenteritis. The overall median incubation period of invasive listeriosis was 8 days (range: 1–67 days) and differed significantly by clinical form of the disease (p<0.0001). A longer incubation period was observed for pregnancy-associated cases (median: 27.5 days; range: 17–67 days) than for CNS cases (median: 9 days; range: 1–14 days) and for bacteraemia cases (median: 2 days; range: 1–12 days). For gastroenteritis cases, the median incubation period was 24 hours with variation from 6 to 240 hours.ConclusionsThis information has implications for the investigation of food borne listeriosis outbreaks as the incubation period is used to determine the time period for which a food history is collected. We believe that, for listeriosis outbreaks, adapting the exposure window for documenting patients’ food histories in accordance with the clinical form of infection will facilitate the identification of food products as the source of contamination. We therefore propose to take an exposure window of 14 days before the diagnosis for CNS and bacteraemia cases, and of 6 weeks before the diagnosis, for pregnancy-associated cases.

An Empirical Study on VC Incubation Period, IPO Market Timing and Post-IPO Performance Based on The Chinese Market

Venture capital (VC) has been the primary financing mode for startup companies in high-tech sectors and helps accelerate IPO process. Existing literature suggests a link between an earlier or later IPO decision and VC investors. Therefore, in this article we select a sample of 341 VC-backed companies that went public in Shanghai and Shenzhen Stock Exchanges from 2004 to 2010, and investigate the effect of industry technological improvement on the length of VC incubation period, IPO market timing and companies’ post-IPO performance. The empirical results indicate: technological improvement shortens VC incubation period and brings about the IPO market timing decision. Furthermore, companies with longer incubation period and high experience VC support, will be granted more patents and have better performance after their IPOs. The findings reveal the potential tight relationship between financial and product markets, and bring to light that the venture capitalists (VCs) play the role of the value creation.

Evolution of HIV incubation times in AIDS patients

Since introduction of highly active antiretroviral therapy (HAART), the incidence of AIDS has gradually declined, although the incidence of HIV infection is largely unknown. We have studied a sample with 10,571 patients whose data were recorded by Spain's public health system, in the Andalusian Register of Cases of AIDS. The diagnoses correspond to the period January 1981 to June 2008. For this period, AIDS incubation times were analyzed by means of the survival and risk functions, using R survival and DTDA libraries. We have studied the evolution of incubation mean times according to specific variables from database. The obtained results show that the mean times of viral incubation presented a growing trend that was greater among women when the study was limited to heterosexual transmission. Stratifying by category of transmission, the longest incubation period was seen for intravenous drug users (IDU). Both gender and IDU transmission were associated with significantly greater survival without AIDS. In contrast, heterosexual transmission or pneumonia diagnosis were associated with lower survival without AIDS.

Reproduction of &lt;i&gt;Omalonyx matheroni&lt;/i&gt; (Gastropoda: Succineidae) under laboratory conditions

The life histories of succineids have received relatively little attention. To evaluate life history characteristics of Omalonyx matheroni, we studied a Brazilian population (Reserva Particular do Patrimônio Natural Feliciano Miguel Abdala, in Caratinga, Minas Gerais, Brazil) under laboratory conditions. The aims of the present study were (1) to describe in detail an appropriate rearing method; (2) to investigate the effects of different temperature and photoperiod conditions; and (3) to assess the effects of self and cross-fertilization on the reproductive biology of these mollusks. We studied the oviposition site, the time to sexual maturity and the influences of photoperiod and temperature on reproductive parameters of O. matheroni reared under laboratory conditions. We tested three combinations of temperature and photoperiod, designated A, B and C (A: 25degreeC, 24 hours of light; B: environmental conditions of temperature and photoperiod, characterized as follows: average maximum temperature=27.1 degreeC, average minimum temperature=18.3 degreeC, average day length=12.06 hours; and C: 25 degreeC, zero hours of light) and two rearing densities (I: isolated and G: grouped) on reproductive parameters (number of eggs per egg mass, number of unviable eggs per mass, egg mass incubation period, and duration of the hatching period). A total of 186 individuals and 565 egg masses were studied. Data were analyzed by Student's t-test, two-way ANOVA and Chi-Square test. Eight generations were produced (March/2004-March/2006), from 35 field specimens, 91% of 3 197 eggs hatched. The time to sexual maturity was approximately three months for individuals reared in groups or in isolation (Student's t-test: t=1.41, df=31, p=0.16); however, they differed significantly in weight (Student's t-test: t=3.6, df=31, p<0.001). Regarding the influences of temperature and photoperiod on reproductive parameters, under natural environmental conditions, individuals produced a greater number of eggs per mass (ANOVA: F2573,=84.15, p<0.001), with a longer incubation period (ANOVA: F2559=170.05, p<0.001). The extreme photoperiod conditions of 24 hours of light or zero hours of light likely imposed stress and could be related to the significant reductions in the number of eggs per mass, and egg incubation period as well as the increased synchrony in egg hatching. No correlations were observed between the number of unviable eggs per mass and the temperature, photoperiod (ANOVA: F2573=0.87, p=0.92) or rearing density (ANOVA: F1 .573=0.21, p=0.64). Individuals reared in isolation under natural conditions produced more eggs per mass and did not presented any disadvantage with respect to the variables analyzed as compared to the animals reared in groups. These results indicate that O. matheroni can successfully reproduce by selfing.

Breeding Biology of the Southern House Wren on Chiloé Island, Southern Chile

We studied the breeding biology of a Southern House Wren (Troglodytes aedon chilensis) population using nest boxes on Chiloé Island, southern Chile (41° S) to make latitudinal comparisons at the intraspecific level. There were no significant differences in body size between adult males and females, although wings were significantly longer in males. Clutch size averaged 4.3 eggs per nest, and brood size was 3.9 nestlings. Egg size averaged 17.3 mm in length and 13.2 mm in width. Incubation and nestling periods averaged 16 days each. The Southern House Wren on Chiloé Island has a larger clutch size than in the tropics, but a smaller clutch size than populations at the same latitude in the Northern Hemisphere. The Southern House Wren has larger eggs and a longer incubation period but a similar nestling period as House Wrens in the Northern Hemisphere.

Influence of the photoperiod on TGF-β1 and p15 expression in hamster Leydig cells

Adult hamsters exposed to short photoperiods show a marked atrophy of their internal reproductive organs, including a reduction in size, though not number of Leydig cells. Transforming growth factor-β1 (TGF-β1) is involved in the regulation of growth and proliferation of different cell types. The aim of the present study was to examine the influence of photoperiod on the protein and gene expression of TGF-β1 and its receptors as well as gene expression of p15. The effect of TGF-β1 on the expression of p15 in purified Leydig cells from regressed and non-regressed hamster testes was also tested. Protein and gene expression of TGF-β1 was detected in both regressed and non-regressed testes. In contrast to the activin receptor-like kinase 1 (ALK-1), the TGF-β1, the activin receptor-like kinase 5 (ALK-5) and the co-receptor endoglin all showed a greater basal expression in regressed than non-regressed hamster testes. Melatonin induced the TGF-β1 mRNA expression in purified Leydig cells from non-regressed testes. The p15 mRNA level was greater in regressed than non-regressed testes. A high dose of TGF-β1 during a short incubation period increased the p15 mRNA level in Leydig cells from non-regressed testes. ALK-5 and mitogen-activated protein kinase (MAPK) p38 might have played a role in this process. In regressed hamster testes, the p15 mRNA level increased due to a low dose of TGF-β1 after short incubation periods and to a high dose after longer incubation periods; in both instances, ALK-5, ERK 1/2 and p38 were involved. Collectively, these results suggest that the alterations in p15 expression, mediated by MAPK, are involved in the shift between the active and inactive states in hamster Leydig cells.

Clinical Leptospirosis in Three Cats (2001–2009)

Based on previous research, cats were thought to have been resistant to the development of clinical signs following infection with Leptospira spp. This case report presents three confirmed, naturally infected clinical cases of feline leptospirosis. The cases presented were all indoor/outdoor cats that were known to hunt. They were also all presented at different stages of renal insufficiency; however, they did not show any liver involvement. The authors suggest that there may be a longer incubation period in cats than dogs and recommend further research in the form of a large, clinical study.

Potential Problems and Possible Solutions for Electronic Information Industry Development in Chongqing

Under the context of improving the world's ecological standards, the developed countries are making higher standards, which may lead to the traditional "high end" industry transferring to China and other developing countries, especially the industry which takes more subtle pollution or longer incubation period. In China, reflection after three decades of development in Guangdong and other pre-open areas may lead to these "high end" industries transfer to the developing area, such as Chongqing. From the example of four confrontations between Greenpeace and Hewlett-Packard, it can be found that the electronic information industry development may bring long-term worries. In this context, in order to avoid the "high end" industries development’s pitfalls, the electronic information industry in Chongqing must be conducted with a comprehensive system of research about its concealed or latent ecological and environmental worries of electronics industry.