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1.
The studies presented enable to evaluate the survival rate of the protozoa in contact with the studied polymers (foils: with polyethylene PE, polyvinyl chloride P-25, P-47, polyester E1 and irradiated collagen L7). It can also be established whether the change of certain morphodynamic parameters could be used to evaluate biological usefulness of plastics. Stereometric method and factor analysis were used in the studies. On the basis of the obtained data polyvinyl chloride P-47 was well assessed, while irradiated collagen L7 showed most negative features.  相似文献   

2.
The microsporidian Encephalitozoon hellem is being reported with increasing frequency in HIV-positive subjects, as an agent of disseminated microsporidiosis without involving the gastrointestinal tract. We describe a case of pulmonary microsporidiosis in a 27-year-old Italian man with AIDS who developed fever, cough, and dyspnea. A chest X-ray showed multiple bilateral pulmonary opacities and mediastinal lymph-node enlargement. Stained smears of bronchoalveolar lavage sediment showed oval structures consistent with microsporidian spores. Viral, bacterial and fungal cultures were repeatedly negative, whereas microsporidia were successfully cultured in human and bovine fibroblast cell lines. Analysis of electron micrographs indicated that the isolate belonged to the genus Encephalitozoon. Based on further immunological, biochemical and molecular studies it was characterized as E. hellem. Even though a temporary improvement with albendazole therapy was noticed, the patient deteriorated clinically and died of severe respiratory distress.  相似文献   

3.
The authors study in chronic pancreatitis the morphology of Wirsung's duct in 31 patients who had undergone repeated operations, 23 of them were submitted in a first stage to an anastomosis between the pancreatic duct and the digestive tract. The main causes of failure were obstructions of the anastomosis, biliary complications and continuation of the pancreatic disease. The difference in prognosis between pancreatitis with a dilated pancreatic duct, and those with a filiform duct, is perhaps due to lesions of different histological appearance and course. The best results were obtained in patients able to give up alcohol and in whom it was possible to carry out a broader anastomosis on a dilated and unobstructed pancreatic duct.  相似文献   

4.
Portal vein flow was recorded by color Doppler sonography in 31 patients with chronic heart failure and 18 control subjects. Compared with patients showing a forward flow (Group A), those with reversed portal vein flow (Group B) had higher prevalence of tricuspid regurgitation (75% vs. 43%), hepatic congestion (100% vs. 30%) and ascites (50% vs. 18%), and showed higher right atrial pressure (25.3 +/- 3.01 mmHg vs. 11.8 +/- 5.75 mmHg, p < 0.01). In controls, portal vein pulsatility ratio was 0.66 +/- 0.08, in Group A it was 0.46 +/- 0.28 (p < 0.01), in Group B -0.60 +/- 0.19 (p < 0.01). Portal vein pulsatility ratio negatively correlated with right atrial pressure (r = -0.87; p < 0.01). In Group A, hepatic congestion, ascites and tricuspid regurgitation were associated with a higher portal vein pulsatility. This study indicates that portal vein pulsatility ratio reflects the level of impairment of the right heart.  相似文献   

5.
About 85-90% of cytoplasmic protein synthesized by young reticulocytes is globin, and about 10% is a polypeptide (I) of molecular weight 64,000 daltons. Maturation of reticulocytes is accompanied by selective reduction in the synthesis of polypeptide I, relative to globin; mature reticulocytes synthesize globin at a high level but make no detectable polypeptide I. Studies in which RNA from young and old reticulocytes was translated in a wheat germ cell-free extract showed that reduction in synthesis of polypeptide I was correlated with a reduction in the amount of translatable mRNA for this protein. Differential destruction of mRNA thus is an important factor in determining the types of proteins made during the final stages of erythropoiesis.  相似文献   

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In conscious chronic gastric and pancreatic fistula dogs (Thomas cannula), secretin was perfused for three hours with a submaximal (GIH, 1.0 C.U./kg.) and a maximal dose (GIH, 8.0 c.u./kg.), according to the following schedule: 1. First hour submaximal stimulus; 2. second hour maximal stimulus; 3. third hour submaximal stimulus. The alkaline and protein components of pancreatic secretion were analyzed in 20-minute sample collections thoughout the three hours. The same protocol was followed in anesthetized dogs subjected to a mind line laparotomy. A biopsy of the pancreatic gland was taken before (control) and at the end of each perfused dose. The secretion showed a significant increase of protein concentration and output when passing from the maximal to the last submaximal secretin perfusion dose. These findings correlated well with the piling up of zymogen and prozymogen granules in the apical zone of the acinar cells during maximal secretin perfusion, with their subsequent discharge into the acinar lumen upon abrupt reversal to the initial secretin submaximal dose. The study confirms that secretin influences pancreatic protein secretion and indicates in addition, that pharmacologic doses of the hormone, have the capacity to block acinar cell zymogen granule release.  相似文献   

8.
BACKGROUND: Neuropeptide Y (NPY), a centrally located neurotransmitter, is known to increase appetite in fasted and satiated animals. In addition to evaluating NPY's effect on eating behavior, this study was intended to determine whether intracerebroventricular (ICV) NPY would have an effect on canine gastric and pancreatic secretion. METHODS: Four dogs were prepared with cerebroventricular guides and gastric and pancreatic fistulas. ICV and intravenous NPY was administered during intragastric titration of a glucose and peptone meal. During this study, gastric and pancreatic secretion was measured, as well as insulin levels and pancreatic polypeptide (PP). An additional set of four dogs were prepared with esophageal fistulas and cerebroventricular guides, and the effect of ICV NPY on sham feeding was studied. RESULTS: ICV NPY significantly increased sham feeding, meal-stimulated gastric and pancreatic secretion, basal gastric acid, pancreatic bicarbonate, insulin levels, and PP. Vagotomy blocked the effect of ICV NPY on gastric acid secretion in a urethane-anesthetized rat model with acute gastric fistula. CONCLUSIONS: ICV NPY increased sham feeding, gastric and pancreatic secretion, insulin levels, and PP in the dogs. NPY's effect on gastric secretion was blocked by vagotomy in a rat model. NPY should be considered a candidate mediator of cephalic phase secretion.  相似文献   

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Canine juvenile-onset insulin-dependent diabetes mellitus is a rare disease. While pancreatic acinar atrophy is a well known picture in the dog, the simultaneous occurrence with an endocrine insufficiency has never been clearly established. The clinical, pathological and immunohistochemical findings of a three-month-old German shepherd dog with insulin-dependent diabetes mellitus concurrent with exocrine pancreatic insufficiency are described.  相似文献   

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A rare case of traumatic occlusion of the carotid artery at the neck caused by a dog bite is reported. A 10-year-old boy presented delayed onset of left hemiparesis after a dog-bite wound in the right neck. CT scan revealed a cerebral infarction in the right basal ganglia, and IV-DSA disclosed complete occlusion of the right internal carotid artery at the neck. The patient was treated conservatively and his left hemiparesis improved, but impaired visual acuity remained on the right side. Repeated IV-DSA 12 days later showed recanalization of the right internal carotid artery. The mechanisms of the traumatic occlusion of the internal carotid artery were discussed with reference to the literature.  相似文献   

13.
Recent findings suggest that peripheral epinephrine enhancement of memory storage may be mediated in part by an increase in circulating glucose levels subsequent to epinephrine release or injection. Because glucose, unlike epinephrine, has ready access to the central nervous system (CNS), it is possible that glucose acts directly on central processes to enhance memory. To test this possibility, rats were trained on a one-trial inhibitory avoidance task and received immediate or delayed injections of glucose in artificial cerebrospinal fluid. On retention tests 24 hr after training, animals that received 3 or 5 μg glucose (in 1 μl cerebrospinal fluid over 3 min) had significantly enhanced performance of the learned response. Findings are consistent with the view that glucose can regulate the storage of new information by acting on central processes. Whether there are additional peripheral contributions to glucose effects on memory remains to be determined. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

14.
余斌 《黄金》1995,16(10):9-12
多排多向向掏槽双排同段多排微差爆破,是一种新的爆破方法。该爆破方案的“随机同时”和““短时微差”作用,促使爆破应力波的叠加及爆炸气体能量利用更加充分,形成的爆丰和交分支现象更为普遍。爆破矿石块度小,大块率低,与常规爆破方法相比,具有明显的优越性。  相似文献   

15.
The aim of the present experiment was to study alterations in the mobility of teeth that occurred during resolution of experimentally induced periodontitis lesions in the dog. 5, 1-year-old, beagle dogs were used in the study. The left and right 4th, 3rd, and 2nd mandibular premolars (4P4, 3P3, 2P2) served as experimental teeth. Periodontal tissue breakdown was initiated by placing plaque-collecting cotton-floss ligatures around the neck of the experimental teeth. The ligatures were replaced to the level of the receding gingival margin 1 x every month. On Day 120, the ligatures were removed and debridement was performed. A groove, parallel to the long axis of the mesial root, was prepared in the mesio-buccal surface of the crowns of 2P and P2. Guided by the groove and with a probing force of 0.5 N, a probe was inserted into the buccal gingival pocket of the mesial root and was attached to the buccal surface. Biopsies including both the mesial and distal root of 2P and P2 and the surrounding hard and soft tissues were harvested. The biopsy procedure was repeated in a similar manner 15 days (i.e. Day 135) and 3 months (i.e. Day 225) after ligature removal in the 4th (4P4) and 3rd (3P3) premolar regions. After fixation, decalcification and sectioning, the biopsy material was exposed to histometric and morphometric measurements. Assessment of the mobility of the experimental teeth was performed on Days 120, 135 and 225 using the Periotest system.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

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Evaluation of peer review activities in the New Mexico Medicaid program (1971 to 1973) showed that it can affect aspects of quality, that is, the appropriateness of the use of injections as judged by medical criteria. Use of injections, nearly 50% of which were antibiotics, declined by more than 60%, from 41 to 16 per 100 ambulatory visits. Still, at the end of the study, 40% of the injections given were considered medically unnecessary. Analyses showed that [1] groups used injections more appropriately; [2] for solo physicians, being board-certified, being a doctor of medicine, and being a pediatrician were all associated with more proper use of injections; [3] 6% of the physicians gave 40% of the medically unnecessary injections, but even their behavior changed dramatically for the better as a result of the peer review system.  相似文献   

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Bovine pancreatic ribonuclease is a DNA "melting" protein, since it binds with greater overall affinity to the single-stranded than to the double-stranded form of natural and synthetic deoxyribose-containing polynucleotides. As such, the DNA-RNase system provides a simple model for the more complex and biologically relevant melting protein-nucleic acid systems. Aspects of the DNA-RNase interactions which are related to the quantitative assessment of this system as a melting protein model are investigated here. A boundary sedimentation velocity technique is used to measure thermodynamic parameters of the interaction; association constants (Kh and Kc) and site sizes (nh and nc) are determined for the interaction of ribonuclease with native (double helical) and denatured (random coil) DNA. It is shown that log Kh and log Kc are linear functions of log [Na+], binding decreasing with increasing Na+ concentration, with Kh about 2 orders of magnitude smaller than Kc at the ionic strengths studied, nh and nc are approximately 8 and approximately 11 nucleotide residues, respectively, indicating that potential binding sites overlap. Binding to both forms of DNA is non-cooperative. It is shown by CD and ultraviolet spectroscopy that the binding of RNase to single- and double-stranded DNA perturbs the conformations of these polynucleotide conformations very little relative to the unliganded structures. Hydrodynamic methods are used to show that RNase binds to native DNA without altering the overall solution structure of the latter; however conditons which permit binding to, and stabilization of, transiently exposed single-stranded sequences result in a collapse of the stiff native DNA structure. We demonstrate by melting transition studies that ribonuclease does bring about an equilibrium destabilization of native DNA and poly [d(A-T)] and, by applying a ligand-perturbed helic in equilibrium coil theory developed by McGhee (McGhee, J.D. (1976) Biopolymers 15, 1345-1375), it is shown that the extent of the observed destabilization is in semiquantitative accord with expectations based on the measured affinity constants and site sizes for RNase binding to both DNA conformations. Spectral methods are used to show that the relative stability of native DNA sequences of varying base composition is the same in the presence and absence of ribonuclease, strongly arguing that this "melting" ligand "traps" single-stranded sequences transiently exposed by thermal fluctuations. RNase also undergoes an order in equilibrium disorder conformational transition as a function of temperature (the denatured form of RNase stabilizes native DNA, while native RNase destabilizes the native double helix), and the coupled equilibria involved in these interacting conformational changes are interpreted and discussed as possible models of genome regulatory interactions.  相似文献   

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