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1.
A rapid dynamic imaging technique based on polar k-space sampling is presented. A gain in temporal resolution is achieved by angular undersampling. A detailed analysis of the point spread function of angular undersampled polar imaging reveals a reduced diameter of the corresponding circular field of view. Under the assumption that dynamic changes are restricted to a local circular field of view, angular undersampled dynamic imaging allows the recording of rapid changes at high temporal and spatial resolution. The theoretical and experimental details of the technique are presented.  相似文献   

2.
While SMAS surgery revolutionized facelift procedures, the single flap created by conventional dissections suffers the drawback that it can only be advanced in one direction and sutured in place under uniform tension. Division of the flap into three segments overcomes this problem and allows independent pull to be applied in different directions to the upper midface, cheek, and neck.  相似文献   

3.
Hereditary haemochromatosis (HH), which affects some 1 in 400 and has an estimated carrier frequency of 1 in 10 individuals of Northern European descent, results in multi-organ dysfunction caused by increased iron deposition, and is treatable if detected early. Using linkage-disequilibrium and full haplotype analysis, we have identified a 250-kilobase region more than 3 megabases telomeric of the major histocompatibility complex (MHC) that is identical-by-descent in 85% of patient chromosomes. Within this region, we have identified a gene related to the MHC class I family, termed HLA-H, containing two missense alterations. One of these is predicted to inactivate this class of proteins and was found homozygous in 83% of 178 patients. A role of this gene in haemochromatosis is supported by the frequency and nature of the major mutation and prior studies implicating MHC class I-like proteins in iron metabolism.  相似文献   

4.
An outbreak of a febrile illness characterized by headache, ocular pain, myalgia, and arthralgia occurred during June 1994 among Peruvian army troops in Northern Peru. On June 14-16, 1994, clinical data and blood samples were obtained from eight soldiers with a febrile illness, and from 26 others who had a history of febrile illness during the past three months. A follow-up blood sample was obtained 107 days later from four of the febrile and seven of the afebrile soldiers. Serum samples were tested for dengue (DEN), Oropouche (ORO), and Venezuelan equine encephalitis (VEE) IgM and IgG antibodies by an enzyme-linked immunosorbent assay (ELISA). Virus isolation was performed by inoculation of newborn mice and Vero cell cultures. Viral isolates were identified by immunofluorescence, ELISA, and nucleotide sequencing. A VEE virus infection was confirmed in three of the eight febrile soldiers, two by virus isolation, and one by serology. Antigenic analysis indicated that one of the virus isolates was similar to VEE subtype I, variety ID, viruses previously isolated in Colombia and Venezuela. Nucleotide sequence data showed that both viral isolates were identical to one another and closely related to VEE ID viruses previously isolated in Peru, Colombia, and Venezuela. Serologic results showed that two of 26 afebrile soldiers had IgM antibody to VEE and four had IgG antibody to VEE; two febrile soldiers had IgG antibody in their first serum samples. Oropouche-specific IgM antibody was detected in one of the eight febrile and five of the afebrile soldiers, and 18 of the 34 soldiers had low titers of ORO IgG antibody titers, which did not meet the diagnostic criteria for confirmed cases. All soldiers were negative for DEN IgM antibody, and 10 had flavivirus IgG antibody that reacted with DEN antigens. These data indicated that VEE ID virus was one of the causes of illness among Peruvians soldiers and that this was the first association of this VEE subtype with human disease in Peru.  相似文献   

5.
The photochemical hypoiodination of cortisol acetonide, without neutralization of the excess of acidity during the work-up of the reaction, led to a mixture of 11 beta,18-oxido-17 alpha,21-dihydroxy-4-pregnen-3,20-dione and 11 beta,19-oxido-17 alpha,21-dihydroxy-4-pregnen-3,20-dione. Side chain cleavage of the former compound gave 11 beta,18-oxido-4-androsten-3,17-dione. The crystal structures of both of these 11 beta,18-oxidosteroids were determined by X-ray. The ring conformations are discussed and compared with those of aldosterone.  相似文献   

6.
Eighty kidney transplants were examined. During the first three months following transplantation, urinary tract infections occurred in 68 patients (85%). Fifty patients (74%) have had a few episodes of infections in the form of either suprainfection or recurrence whereas in the remaining patients there was only one episode of urinary infection. No difference in infection incidence was noted in both men and women. Ninety percent of urinary infections occurred within the first 4 weeks following transplantation. The most frequent cause of the urinary tract infections were gram-negative bacilli of Enterobacteriaceae family. In case of multiple infections there was a high percentage of gram-positive cocci.  相似文献   

7.
Different cited evidences on parasitic amoebae and amoebo-flagellates belonging to the Lobosea and Heterolobosea classes (Pages, 1987) have been reviewed. Special attention is paid to various degree of their adaptation to parasitic mode of life, which ranges from a parasitism on a border with commensalism to true parasitism (both facultative and obligatory ones). Besides the coprophilous and commensal species, the number of true parasites among the Lobosea and Heterolobosea classes is comparatively small. In many cases, both facultative and obligatory parasites cause the death of their hosts. Apparently this strongly pronounced pathogenicity of parasitic amoebae and amoebo-flagellates suggest a recent origin of such parasite-host systems. Pathogens of amoebic dysentry, primary amoebic meningoencephalitis and granulomatous amoebic encephalitis are specially considered. In the Russian text-books on a parasitology the information on most of them, except Entamoeba hystolytica, is either totally absent or very scare and out of date.  相似文献   

8.
9.
HSV-1 mutants in the RL-1 gene encoding the ICP34.5 protein have been demonstrated to have diminished neurovirulence in brain yet replicate as efficiently as parental virus in transformed tissue culture cells. Thus they have been proposed as candidates viruses for human brain tumor therapies. Evaluation of their replicative properties and pathogenesis within the nervous system has been limited. As most patients undergoing therapies for brain tumors are likely to be immunocompromised, it will be important to understand the pathogenesis of these viruses in immunocompromised hosts. To this end, the lateral ventricle of nude mice was injected with high (2.5 x 10(7) PFU), medium (10(5) PFU), or low dose (10(3) PFU) HSV-1 variant-1716, which has a deletion in the RL-1 gene. Ten of 10 mice died within 2-3 days following the high titer infection. Six of 19 animals with medium titer infection died within 9 days, and viral antigens were seen in ependymal cells as well as neurons within the brainstem and thalamus. Although only two of 19 animals became moribund 18 days after medium titer viral infection, many neocortical and hippocampal neurons were positive for HSV-1 antigens. However, plaque-purified viral isolates recovered from brain homogenates of these animals demonstrated no increase in pathogenicity. Nine of 20 animals died following low dose infection; six of these animals, from which tissue was analyzed, all had many HSV antigen-positive neurons in the neocortex and hippocampus. These data imply that if this type of virus is used for human brain tumor therapy immunosuppressed patients may suffer from significant viral pathogenesis outside the tumor.  相似文献   

10.
11.
OBJECTIVE: To review experience with 20 women treated for sciatic hernia between 1993 and 1997. METHODS: Patients with chronic pelvic pain and sciatic hernias, identified retrospectively from chart review, were seen during a 46-month period that covered the surgical experience at our institution and included approximately 1100 cases. The median length of follow-up was 13 months (range 3-36). RESULTS: Sciatic hernia was diagnosed in 20 white women with chronic pelvic pain and was treated using laparoscopy. In 14 cases the hernias were right sided, in five they were left sided, and in one they were bilateral. All sciatic hernias contained the ipsilateral ovary alone or with its fallopian tube. All 20 patients reported symptomatic relief at follow-up. CONCLUSION: Sciatic hernia is a cause of chronic pelvic pain and should be considered in the differential diagnosis.  相似文献   

12.
OBJECTIVES: To provide a contemporary account of the treatment and outcomes of acute coronary attacks in England and Wales and to identify strategies that might improve the outcome. DESIGN: Two year community and hospital based study in three British health districts. SETTING: Health districts of Brighton (population 282,000), South Glamorgan (408,000), and York (264,000). SUBJECTS: 3523 men and women under 75 years of age who died outside hospital from acute coronary causes, who were admitted to hospital with acute myocardial infarction, or who developed acute infarction or died unexpectedly from acute coronary causes while they were already in hospital. INTERVENTIONS: Attempted resuscitation in people having a cardiac arrest outside hospital. MAIN OUTCOME MEASURES: Total case fatality, case fatality outside and inside hospital, and the effect of resuscitation on case fatality outside hospital. RESULTS: 1589 patients died within 30 days of the acute event. Case fatality was 45% (95% confidence interval 43% to 47%), rising from 27% (160/595) (23% to 31%) at age < 55 years to 53% (1019/1916) (51% to 55%) at 65-74 years. Overall, 74% (1172/1589) (72% to 76%) of fatal events happened outside hospital, and there was a negative age gradient (P < 0.001) such that 91% (145/160) (87% to 95%) of fatalities occurred outside hospital at age < 55 compared with 70% (710/1019) (67% to 73%) at 65-74 years. Without successful resuscitation of 55 patients outside hospital, total case fatality at 30 days would have risen from 45% to 46.7%. CONCLUSION: Opportunities for reducing fatality from acute coronary attacks lie mainly outside hospital. These results and others imply that survival from cardiac arrest outside hospital might be trebled by improved ambulance and patient response. Proper application of secondary preventive measures for patients with coronary disease could have an even larger impact.  相似文献   

13.
Complaint of a burning mouth is an increasingly common problem in the aging population. This has remained an enigma for the treating clinician, because visible pathologic lesions or processes are usually not evident. Local, systemic and environmental causes must be assessed to elicit the predisposing factors. Some suggestions for managing burning mouth syndrome are offered.  相似文献   

14.
Abstract

Mercury pollution in the Amazon represents one of the most serious environmental issues faced by mankind today. From 70 to 170 t of Hg are discharged annually into the Amazon environment from informal gold mining operations. Vegetation fires are also a major source of Hg emissions with the form being more reactive than that from mining activities. The extent of biota contamination is also more widespread. Mercury must be rendered soluble and then converted into methylmercury in order to accumulate in the food-chain. Generally, it is regarded that oxidation of Hg must occur to produce significant dissolution. In this work, we examine the stability of metallic Hg in aquatic environments. In contact with organic acids, evidence of Hg–organic complex formation has been found from both thermodynamic analysis and electrochemical experiments. Although methylation of these soluble species is not fully understood, formation of such complexes in dark-water rivers must contribute to increased bioavailability. © 1997 Canadian Institute of Mining and Metallurgy. Published by Elsevier Science Ltd. All rights reserved.

Résumé

La pollution par le mercure en Amozonie représente une des questions environnementales les plus sérieuses affront é es par l'humanité aujourd'hui. De 70 à 170 t de Hg sont déchargées annuellement dans l'environnement de l'Amazone en provenance des opérations irr égulières de mines d'or. Les feux de végétation sont également une source majeure d'émmisions de Hg, cette formeé tant plus r é active que celle proven ant activités minières. Le degré de contamination du biome est aussi plusétendu. Pour pouvoir s'accumuler dans la chaine alimentaire, le mercure doit etre solubilise et ensuite converti en m é thylmercure. généralement, on considèrequ'il doit y avoir oxydation du Hg pour qu'une dissolution importante se produise. Dans ce travail, nous examinons la stabilité du Hg mètallique en environnements aquatiques. On a démontré, tant par analyse thermodynamique que par des expériences électrochimiques, que lorsqu'en contact avec des acides organiques, il y avait évidence de formation de complexe Hg-mati è re organique. Bien que la méthylation de ces espèces solubles ne soit pas compl è ment comprise, la formation de tells complexes dans les rivi è res à eaux noires doit contribuer à une biodisponibilité accrue. © 1997 Canadian Institute of Mining and Metallurgy. Published by Elsevier Science Ltd. All rights reserved.  相似文献   

15.
16.
A single intratracheal instillation of porcine pancreatic elastase (PPE, 100 U/Kg) induces in rabbits bronchial secretory cell metaplasia as well as emphysematous changes. The mucus hypersecretion and the marked reduction of ciliated cells matched by a high percentage of atypical cilia are responsible for the delayed mucociliary clearance in this model. S-Carboxymethylcysteine lysine salt (SCMC-LYS, 0.35 g/Kg b.w.), given per os daily for 10 days starting 2 days before elastase administration, significantly ameliorated the mucociliary clearance. The pharmacological treatment did not modify the degree of secretory cell metaplasia and the percentage of atypical cilia, or prevent the alveolar wall destruction. At TEM examination, the morphological aspects of secretion occurring in bronchial tree of PPE-treated animals were rarely visible in the PPE + SCMC-LYS treated group. The beneficial effect of SCMC-LYS on mucociliary clearance may be ascribed to an antisecretagogue effect of this drug through elastase inhibition and to a reduction of mucus viscosity.  相似文献   

17.
The aim of this study was to determine whether the endometrium acts as a reservoir for Candida albicans in cases of recurrent vaginal candidiasis. Twenty-five women with documented history of recurrent vaginal candidiasis were enrolled in the study and endometrial samples were cultured for Candida albicans. Only two patients had positive cultures for Candida albicans. Therefore, we concluded that the endometrium is not a common reservoir for Candida albicans.  相似文献   

18.
Physicians numerical increment in Brazil presented critical variations in recent years. So, annual means of graduated physicians were: 1972-1976, 7,082; 1977-1981, 8,304; 1982-1986, 7,542; 1987-1991, 7,058. In spite of this tendency to reduction, physicians per 10,000 inhabitants rate increased in the last 20 years: 5.96 in 1972, 4.59 in 1982 and 13.87 in 1992. Percentual increment of physicians per year represents 3.5% of the total number of active professionals/against less than 2% in the total population increase in Brazil. Thus that rate has a clear tendency to increase in the next years.  相似文献   

19.
An epidemiological survey on human calicivirus (HuCV) infections and associated gastroenteritis in infants was conducted to clarify the prevalence of HuCV infections in infants and adults in Kenya. Enzyme immunoassays (EIAs) for three genogroups of HuCVs, Norwalk virus (NV), Mexico virus (MXV), and Sapporo virus (SV), were used to detect antigen or antibody. We tested 1,431 stool samples obtained from children younger than 6 years old with acute gastroenteritis who visited outpatient clinics in three districts in Kenya from August 1991 to July 1994. Thirty-two (2.2%) of these stool samples were positive for SV antigen. Only one (0.1%) of 1,186 samples was positive for NV antigen and none of 246 samples was positive for MXV antigen. One hundred ninety-three serum samples were tested for antibodies to NV and MXV, and 64 of them were examined for antibody to SV. The pattern of the age-related prevalence of serum antibody to NV was different from that of antibodies to MXV and SV. The acquisition of serum antibodies to HuCVs in the three genogroups appeared in early childhood, at about 1 to 2 years of age. The prevalence of serum antibody to NV was low (about 60%) throughout adulthood compared with a high prevalence of antibody (approximately 80 to 90%) to MXV and SV. These data indicate that infections with viruses in the three genogroups of HuCVs are common in Kenya, and immunological responses to NV may be different from those to MXV and SV. The EIAs for the detection of NV and MXV antigens appear to be quite specific for prototype NV and MXV strains, respectively, so that they can detect only a few strains of HuCVs related to them. Alternatively, NV and MXV caused less severe infections that did not bring children to the outpatient clinics for gastroenteritis in Kenya.  相似文献   

20.
The prevalence and severity of drug-resistant malaria is emerging rapidly in the Amazon basin of Brazil. In support of clinical trials using the new antimalarial drug combination of atovaquone and proguanil, we performed in vitro drug sensitivities, molecular characterization of parasite populations using the circumsporozoite protein, merozoite surface antigen-1 (MSA-1), and MSA-2 markers, and an analysis of the Plasmodium falciparum multidrug resistance (pfmdr1) gene sequence and copy number in 26 isolates of P. falciparum obtained in a gold-mining endemic area in Peixoto de Azevedo, Mato Grosso State. All 26 isolates were found to be resistant to chloroquine (50% inhibitory concentration [IC50] = 100-620 nM) and sensitive to mefloquine (IC50 < 23 nM) and halofantrine (IC50 < 6 nM). The isolates also show reduced susceptibility to quinine (IC50 = 48-280 nM). Sequence analysis of the pfmdr1 gene revealed Asn, Phe, Cys, Asp, and Tyr in positions 86, 184, 1034, 1042, and 1246, respectively. These point mutations were similar to that previously described in other Brazilian isolates. Southern blot analysis revealed no amplification of the pfmdr1 gene. These results suggest that three different mechanisms for drug resistance exist for chloroquine, mefloquine, and quinine.  相似文献   

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