Effect of thyroxine on some digestive enzymes of the adult male toad,Bufo melanostictus

Thyroxine is known to play an important role during the developmental process of amphibians. The present work is designed on the hypothesis that a functional relationship exists between the thyroid gland and digestive physiology in the adult toad. Three doses of thyroxine (25 microg/100 g; 50 microg/100 g; 100 microg/100 microg body weight) were orally administered daily to the adult male toad, Bufo melanostictus and changes in -amylase, pepsin, trypsin, and esterase activities of the different zones of the digestive tract, pancreas and liver were observed. The observations were made on 7, 15, and 30 days of thyroxine treatment. The result shows that the dose of 25 microg increases the enzyme activities in the gastrointestinal tract, liver and pancreas of 7 days treatment. However, prolonged treatment with all the doses shows little effect on these enzymes. The pattern of changes in the enzymatic activities in the digestive tract of the adult male toads show more advanced compartmentalization than that of fishes. It is also found that site-specific enzyme production is not pronounced in this amphibious vertebrate. It is proposed that a positive functional relationship between thyroxine and digestive enzymes exists in the adult male toad.     

A model for the study of the oral administration of peptide hormones.

The intragastric administration of lysine vasopressin (LVP) to rats is used as a model to study the biological activity of orally administered peptide hormones. Using a modification of the antidiuretic assay of Sawyer, LVP given by stomach tube caused a significant antidiuresis that was dose dependent in doses of 300 to 2000 mU. The simultaneous administration of the protease inhibitor, Trasylol, increased the antidiuretic effect of LVP. The synthetic peptide (1-deamino, 4 valine)-8-D-arginine-vasopressin also caused a dose-dependent prolonged and significant antidiuresis. No pressor effect was observed after intragastric administration of LVP in doses up to 40 U/rat. We are now using this model to test other procedures for enhancing the activity of lysine vasopressin administered in the gastrointestinal tract such as encapsulation into liposomes. The information gained with vasopressin will then be applied to insulin with the ultimate goal of making oral administration practical.     

Study of the influence of peroral zincacin on the removing of ingested Americium

Effect of different cincacine doses was studied in rats ingesting americium citrate during 2 weeks. As a result new data showing the possibility and efficacy of per oral cincacine administration at americium intake into digestive tract have been obtained. Dose dependence of cincacine efficacy has been stated for per oral 241Am intake. Preparation administration at a dose of 25 mumol/kg reduces amount of 241Am in skeleton, liver and kidney by 93, 90 and 33%, respectively and is optimum for radionuclide removal from the body and for the prevention of its deposition in organs. Digestive system organs and kidney structure at cincacine administration at a dose of 150 and 300 mumol/kg) to the rats ingesting 241Am have been studied.     

Antagonistic interrelationships of Bifidobacterium bifidum i Proteus vulgaris in vitro in the digestive tract of gnotobiotic chicks]

The antagonistic relations between Bacterium bifidum, strain I/850 phi, and Proteus vulgaris, strain F-30, were studied. These organisms, when introduced together in equal doses into the digestive tract of gnotobiotic chickens in a single administration, were shown to create certain ecological correlations in various organs with the prevalence of bifidobacteria which exerted no negative influence on Proteus vulgaris. The additional daily administration of bifidobacteria for 3 days running in doses 1000 times as great as the initial dose, the content of both dibifobacteria and Proteus vulgaris in the intestine being at that time at its maximum, resulted in the suppression of the growth of Proteus vulgaris. Our findings indicate that the influence of the pH of the medium should be considered in order to obtain the evidence of significantly pronounced antagonistic relations between the two organisms in vitro.     

Yeasts in the gastrointestinal tract of preweaned calves and possible involvement of Candida glabrata in neonatal calf diarrhea

To examine the possibility of a mycotic involvement in neonatal calf diarrhea (NCD) the presence of fungi was assessed in (a) the intestinal contents of dead calves and fecal samples submitted for routine laboratory examination, (b) fecal specimens, sampled once in winter and once in summer, of calves raised on 2 farms with different management systems, and (c) mucosal scrapings of various segments of the digestive tract of a diarrheic calf, massively shedding Candida glabrata.C. glabrata was the most prevalent fungal species isolated from the routine samples. It was the only fungus which was shed by the calves on the 2 farms, for continuous, more or less prolonged periods, but exclusively in the winter months. Diarrhea and C. glabrata shedding seemed to be associated. C. glabrata colonized the abomasum (the functional equivalent of the monogastric stomach) but not the other segments of the digestive tract of the euthanized calfBased on the findings of this study it seems that while some yeast species may be considered as commensals of the digestive tract of calves, and consequently their isolation from intestinal contents or fecal samples has no clinical significance, others, such as C. glabrata may be involved in enteric pathogenic processes. Moreover, characteristics of the culture, previous chemotherapeutic treatments, the animal's age and possibly climatic conditions should be taken into account before deciding on the fungal isolate's clinical relevance. Determination of mycotic involvement in NCD by routine mycological examination of intestinal contents and fecal samples of diarrheic calves may be useful to avoid unnecessary and potentially harmful antibacterial therapy.This revised version was published online in October 2005 with corrections to the Cover Date.     

Genetically engineered yeasts as a new delivery vehicle of active compounds to the digestive tract: In vivo validation of the concept in the rat

An innovative “biodrug” concept based on oral administration of living recombinant microorganisms as a vehicle to deliver active compounds directly into the digestive tract has recently been developed. To validate this concept, we studied a recombinant Saccharomyces cerevisiae strain in order to investigate its viability and its ability to produce a protein (glutathione-S-transferase (GST)-V₅H₆) in the rat. Following oral administration, the recombinant yeast showed a survival rate of around 40% in the upper parts of the digestive tract, but was more sensitive to the conditions in the large intestinal, where viability dropped to 1%. Western blot analysis was able to detect the model protein throughout the digestive tract, including stomach, duodenum, jejunum (proximal, median and distal), ileum, cecum and colon. The gastrointestinal sac technique was employed to quantify GST-V₅H₆ in all the digestive compartments. These results suggest that S. cerevisiae may represent a useful host for producing compounds of interest directly in the digestive tract.     

Four new yeasts in the Candida mesenterica clade associated with basidiocarp-feeding beetles

We isolated five yeasts related to Candida mesenterica from the digestive tract, frass, and habitat of beetles in six families inhabiting basidiocarps. Based on rDNA sequence comparisons and phenotypic characters, the yeasts were identified as Kodamaea ohmeri and four undescribed taxa. Phylogenetic analysis of combined small and large subunit ribosomal DNA sequences placed the five taxa in a statistically well supported clade with C. mesenterica, Candida suecica and other yeast species known from basidiocarps, including 'Endomyces scopularum' (CBS154.92 and 155.92), Candida fukazawae, Candida fungicola and Candida sagamina. Only one of the new taxa produced ascospores; the other three reproduced only asexually. The yeasts appear to be less closely associated with beetles than with the beetle habitat. The new species and their type strains are Kodamaea laetipori (type strain NRRL Y-27713 T), Candida derodonti (type strain NRRL Y-2771 1 T), Candida arcana (type strain NRRL Y-27712 T) and Candida plutei (type strain NRRL Y-27715 T).     

Protection of mice from lethal endogenous Candida albicans infection by immunization with Candida membrane antigen

The protective effects of immunization with Candida membrane antigen (CMA) on a systemic infection originating from intestinally colonized Candida albicans were examined. The colonization of orally inoculated C. albicans in the intestinal tract was established in BALB/c mice that had been concomitantly treated with oral doses of antibacterial drugs. In these animals, a systemic dissemination of C. albicans with fatal outcome was induced by a repeated dosing of prednisolone. In this endogenous infection model, the effects of immunization by CMA on the infection were examined. CMA-immunized mice showed a longer lifespan than unimmunized mice. The protective effect of CMA immunization in immunosuppressed mice was also measured by a decrease in body weight loss after treatment with prednisolone and in the number of viable Candida cells in the target organs, the kidneys and livers. However, the CFU of C. albicans in the intestinal tract was not significantly lowered. These results suggest that CMA immunization inhibited the dissemination of systemic Candida infection from the intestinal tract induced by treatment with prednisolone.     

Clinical spectrum of invasive candidiasis in critically ill non-neutropenic patients

Invasive Candida spp. infections in non-neutropenic critically ill patients admitted to intensive care units can be classified as focal and systemic. Both types of infection usually occur after episodes of candidemia, although some focal infections may be of exogenous development, like those occurring after trauma or be device-related.The clinical spectrum of invasive Candida spp. infections includes focal urinary tract, abdominal, ocular, respiratory tract, renal and hepato-biliary infections, as well as systemic infections like candidemia and acute systemic candidiasis with multiorgan involvement after hematogenous seeding. Candida spp. isolates in "significant" samples, like synovial fluid, cerebrospinal fluid and blood cultures, represent true infection. However, the diagnosis of invasive infection based on "non-significant" samples, like surgical drains and digestive tract exudates, requires additional criteria. The total number of isolates from different sites, the presence of risk factors, the clinical host response, as well as severity of illness need to be taken into account for the diagnosis of invasive candidiasis. The clinical signs of systemic infection due to Candida spp. are completely non-specific and cannot be differentiated from bacterial peritonitis, urinary tract infection or bacteremia. These infections may be associated with signs of sepsis,severe sepsis, septic shock or multiorgan dysfunction. In the future clinical multicentre observational and interventional studies are necessary to reach agreement on clinical definitions and classification of invasive Candida spp. infections in critically ill non-immunocompromised patients.     

Schistosoma mansoni: uptake of exogenous hemeproteins by schistosomules grown in vitro

The uptake and fate of the hemeproteins horseradish peroxidase (HRPO) and hemoglobin (Hb) by schistosomules of Schistosoma mansoni maintained in vitro were studied by electron microscopy and cytochemical techniques. After administration of HRPO, reaction product was observed initially in the lumen of the digestive tract, and, after 2 hr of feeding, reaction product was also visible in the cytoplasm of the gastrodermis. There was no evidence of pinocytosis. After administration of Hb, reaction product was observed only in the lumen of the digestive tract. As is found following red blood cell feeding, digestive pigment was formed in the lumen of the gut following Hb feeding. The possible significance of these findings is discussed.     

临床酵母样真菌的感染特点及耐药性研究

目的了解临床酵母样真菌的感染类型、分布以及耐药情况,为临床诊断治疗提供合理的用药依据.方法采用常规方法进行真菌培养,用科玛嘉显色培养基联合法国生物梅里埃API 20C AUX鉴定条进行鉴定,药敏试验采用微量稀释法.结果864株酵母样真菌中,白色念珠菌619株（71.6%）,其次为热带念珠菌116株（13.4%）和克柔念珠菌47株（5.4%）,非白色念珠菌感染的比例逐年上升（21.5%）.其中,呼吸道标本酵母样真菌检出率最高,达79.7%,其次是消化道为8.8%,泌尿道为4.7%.科室分布依次为干部科、呼吸科、急诊内科、血液科等;白色念珠菌对两性霉素B、5-氟胞嘧啶高度敏感,达90%以上,对氟康唑和伊曲康唑的敏感性有所降低.结论酵母样真菌的检出率与患者基础疾病密切相关;对氟康唑等药物的敏感性有下降的趋势,未发现对4种药物同时耐药的菌株,提示在治疗中,药敏监测是非常必要的.     

Mycotic flora in the lower digestive tract of feral pigeons (Columba livia) in the El Paso, Texas area.

Fourteen species of fungus were isolated from the lower digestive tract of 39 of 80 pigeons. Sixteen pigeons had concurrent isolations while two harbored three species. Fungi isolated were Allescheria boydii, Aspergillus spp., Candida krusei, Chrysosporium spp., Geotrichum candidum, Mucor spp., Paeciliomyces spp., Penicillium spp., Rhizopus spp., Rhodotorula spp., Scopulariopsis spp., Streptomyces spp., and Trichosporon cutaneum. There was no apparent evidence that these fungi were associated with clinical disease in any of the pigeons.     

Experimental quantification of long distance dispersal potential of aquatic snails in the gut of migratory birds

Many plant seeds and invertebrates can survive passage through the digestive system of birds, which may lead to long distance dispersal (endozoochory) in case of prolonged retention by moving vectors. Endozoochorous dispersal by waterbirds has nowadays been documented for many aquatic plant seeds, algae and dormant life stages of aquatic invertebrates. Anecdotal information indicates that endozoochory is also possible for fully functional, active aquatic organisms, a phenomenon that we here address experimentally using aquatic snails. We fed four species of aquatic snails to mallards (Anas platyrhynchos), and monitored snail retrieval and survival over time. One of the snail species tested was found to survive passage through the digestive tract of mallards as fully functional adults. Hydrobia (Peringia) ulvae survived up to five hours in the digestive tract. This suggests a maximum potential transport distance of up to 300 km may be possible if these snails are taken by flying birds, although the actual dispersal distance greatly depends on additional factors such as the behavior of the vectors. We put forward that more organisms that acquired traits for survival in stochastic environments such as wetlands, but not specifically adapted for endozoochory, may be sufficiently equipped to successfully pass a bird's digestive system. This may be explained by a digestive trade-off in birds, which maximize their net energy intake rate rather than digestive efficiency, since higher efficiency comes with the cost of prolonged retention times and hence reduces food intake. The resulting lower digestive efficiency allows species like aquatic snails, and potentially other fully functional organisms without obvious dispersal adaptations, to be transported internally. Adopting this view, endozoochorous dispersal may be more common than up to now thought.     

Feast to famine: The effects of food quality and quantity on the gut structure and function of a detritivorous catfish (Teleostei: Loricariidae)

The gastrointestinal (GI) tract and associated organs are some of the most metabolically active tissues in an animal. Hence, when facing food shortages or poor food quality, an animal may reduce the size and function of their GI tract to conserve energy. We investigated the effects of prolonged starvation and varying food quality on the structure and function of the GI tract in a detritivorous catfish, Pterygoplichthys disjunctivus, native to the Amazonian basin, which experiences seasonal variation in food availability. After 150 days of starvation or consumption of a wood-diet too low in quality to meet their energetic needs, the fish reduced the surface area of their intestines by 70 and 78%, respectively, and reduced the microvilli surface area by 52 and 27%, respectively, in comparison to wild-caught fish consuming their natural diet and those raised in the laboratory on a high-quality algal diet. Intake and dietary quality did not affect the patterns of digestive enzyme activity along the guts of the fish, and the fish on the low-quality diet had similar mass-specific digestive enzyme activities to wild-caught fish, but lower summed activity when considering the mass of the gut. Overall, P. disjunctivus can endure prolonged starvation and low food quality by down-regulating the size of its GI tract.     

肿瘤患者深部真菌感染的菌株分布及耐药性分析

探讨肿瘤患者深部真菌医院感染的病原菌分布特点及耐药现状。回顾性分析2008年1月至2009年12月哈尔滨医科大学第一临床医学院住院肿瘤患者送检标本分离出的173株真菌的分布及耐药情况。肿瘤患者深部真菌医院感染以下呼吸道感染为主,占76.3%,真菌种类主要是白假丝酵母菌(74.6%);真菌药敏试验结果表明,深部真菌对两性霉素B和5-氟胞嘧啶耐药率均5%;对伊曲康唑及伏立康唑的耐药率为0~6.5%;对氟康唑耐药率有上升趋势,为2.5%~25.0%。临床分离的真菌主要集中在呼吸道标本,以白假丝酵母菌为主,对抗真菌药物普遍敏感,应积极治疗,合理利用抗真菌药物,改善患者预后,减少耐药菌株的产生。     

Temporal changes in digestive enzyme activities in the gastrointestinal tract of European eel (Anguilla anguilla) (Linneo 1758) following feeding

Changes occurring after feeding in the digestive enzyme activities of European eel were investigated to provide some insights into the digestive physiology of this fish. Total and specific proteases, amylase and lipase activities were measured using standard biochemical assays over a 24 h cycle in fed eels, compared to starved ones, under the same rearing conditions. In the gastrointestinal tract of fed eels quantitative changes started 4 h after feeding and continued later on; conversely, in starved eels enzyme activities remained unchanged over time. In fed eels, total and specific protease activities showed an overall increasing trend in the intestine, while in the stomach they progressively decreased to values 22–50% lower than those measured at the pre-feeding time; this behaviour probably reflected the progression of digesta along the intestinal tract. The prolonged secretory response of European eel to food ingestion proved its extended activity in the digestive process.     

Seizure induction by pentylenetetrazol in rodents receivingCandida albicans glycoprotein orally

Oral administration of extracellularCandida albicaus glycoprotein produces increased proneness to seizures in mice and rats when tested with pentylenetetrazol in the experimental conditions reported.Dosages of 0.25 ug/g of body weight in mice and rats applied for a period of five weeks were enough to produce increased proneness to seizures. It appears that the substance is absorbed from the stomach or intestine and also that its detoxication or excretion is at such a slow rate that it accumulates. Introducing to the stomach much larger dosages could cause increased proneness to seizures to be obtained within six hours. Due to the frequent presence ofCandida albicans in humans and the high probability ofCandida albicans glycoprotein production in vivo, it is possible that the level of this substance may accumulate to produce increased proneness to seizures. The states of tenseness, increased sensitivity and hyperactivity could possibly occur in the same pathological process.A renewal of interest in the possible role of intestinal intoxication in human pathology appears to be indicated. Fungi which are harbored in the digestive tract could be the important source of such toxic substances.This work was supported partially byDora Kaplan, Joan Sloan, Cathy Cooper. Memorial Funds and the Roon Foundation.     

石磺消化系统的组织学观察

对石磺消化系统各部分结构进行组织学观察.石磺的消化系统由消化道和消化腺两部分组成.消化道包括口、食道、贲门胃、幽门胃、中肠和后肠,不具吻;消化腺包括肝胰腺、唾液腺和肛门腺.在光学显微镜下,消化道由粘膜层、粘膜下层、肌层和外膜4层组成;肌层主要为环肌,粘膜层主要为柱状细胞.肝胰腺甚为发达,组织结构显示肝胰腺由很多分支的腺管组成,腺管由腺细胞、分泌细胞等组成.唾液腺和肛门腺发达.     

Survival, physiology, and lysis of Lactococcus lactis in the digestive tract.

The survival and the physiology of lactococcal cells in the different compartments of the digestive tracts of rats were studied in order to know better the fate of ingested lactic acid bacteria after oral administration. For this purpose, we used strains marked with reporter genes, the luxA-luxB gene of Vibrio harveyi and the gfp gene of Aequora victoria, that allowed us to differentiate the inoculated bacteria from food and the other intestinal bacteria. Luciferase was chosen to measure the metabolic activity of Lactococcus lactis in the digestive tract because it requires NADH, which is available only in metabolically active cells. The green fluorescent protein was used to assess the bacterial lysis independently of death. We report not only that specific factors affect the cell viability and integrity in some digestive tract compartments but also that the way bacteria are administrated has a dramatic impact. Lactococci which transit with the diet are quite resistant to gastric acidity (90 to 98% survival). In contrast, only 10 to 30% of bacteria survive in the duodenum. Viable cells are metabolically active in each compartment of the digestive tract, whereas most dead cells appear to be subject to rapid lysis. This property suggests that lactococci could be used as a vector to deliver specifically into the duodenum the proteins produced in the cytoplasm. This type of delivery vector would be particularly appropriate for targeting digestive enzymes such as lipase to treat pancreatic deficiencies.     

Recombinant Saccharomyces cerevisiae strain expressing a model cytochrome P450 in the rat digestive environment: viability and bioconversion activity

An innovative "biodrug" concept, based on the oral administration of living recombinant microorganisms, has recently emerged for the prevention or treatment of various diseases. An engineered Saccharomyces cerevisiae strain expressing plant P450 73A1 (cinnamate-4-hydroxylase [CA4H] activity) was used, and its survival and ability to convert trans-cinnamic acid (CIN) into p-coumaric acid (COU) were investigated in vivo. In rats, the recombinant yeast was resistant to gastric and small intestinal secretions but was more sensitive to the conditions found in the large intestine. After oral administration of yeast and CIN, the CA4H activity was shown in vivo, with COU being found throughout the rat's digestive tract and in its urine. The bioconversion reaction occurred very fast, with most of the COU being produced within the first 5 min. The gastrointestinal sac technique demonstrated that the recombinant yeast was able to convert CIN into COU (conversion rate ranging from 2 to 5%) in all the organs of the rat's digestive tract: stomach, duodenum, jejunum, ileum, cecum, and colon. These results promise new opportunities for the development of drug delivery systems based on engineered yeasts catalyzing a bioconversion reaction directly in the digestive tract.