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1.
Nucleotide residue U89 in the D loop of Escherichia coli 5S rRNA is adjacent to two domains of 23S rRNA in the large ribosomal subunit [Dokudovskaya et al., RNA 2 (1996) 146-152]. 50S ribosomal subunits were reconstituted containing U89(C, G or A) mutants of 5S rRNAs and the activities of the corresponding 70S ribosomes were studied. The U89C mutant behaves similarly to the wild-type 5S rRNA. Replacement of the pyrimidine base at position U89 by more bulky purine bases impairs the incorporation of 5S rRNA into 50S subunits, whereas the particles formed showed full activities in poly(U)-dependent poly(Phe) synthesis in the presence of either U89G or U89A 5S rRNA mutants. The activity of the reconstituted particles depends on the incorporation of 5S rRNA in agreement with early observations.  相似文献   

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Intravascular malignant lymphomatosis (IML) is a rare form of extranodal non-Hodgkin lymphoma characterized by proliferation of malignant lymphoid cells within the lumen of small blood vessels. We describe a case of IML presenting with non-specific pulmonary symptoms, weight loss, intermittent fever and a confusing collection of laboratory findings. Later on the patient developed cardiac symptoms, and finally diffuse cerebral symptoms and skin lesions. His condition deteriorated and he died within six months. The diagnosis of IML was made at autopsy. Complete remission and long-term disease-free survival may be obtained with standard chemotherapy directed at high-grade lymphomas. It is important to remember IML in the differential diagnosis of patients with confusing and changing ischaemic symptoms and signs from several organs.  相似文献   

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A 75-year-old man was admitted because of non-Hodgkin's lymphoma (histology undetermined) of the rib. A complete remission was achieved after CHOP therapy and irradiation. One year later, high fever, thrombocytopenia and liver dysfunction developed. Bone marrow aspirate revealed a hypoplastic marrow with hemophagocytic histiocytes, and a diagnosis of hemophagocytic syndrome (HPS) was made. Although no lymphomatous lesions were detected, HPS due to relapsed lymphoma was strongly suspected. The patient received MEVP therapy including etoposide and prednisolone, but without any improvement. Soon after the initiation of CPT-11 and adriamycin (ADM) therapy, all symptoms of HPS disappeared. This combination chemotherapy was repeated over a three-week span, and the patient remained in partial remission for the next 10 months. In November 1997, a tumor developed in the paranasal sinus, and the patient died three months later. The autopsy disclosed many B lymphoma cells filling the small vessels of almost all organs, and a final diagnosis of intravascular lymphomatosis (IVL) was made. These findings indicate that combination CPT-11 and ADM therapy is effective for cases of IVL accompanied by HPS that are refractory to conventional chemotherapies.  相似文献   

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Intravascular malignant lymphomatosis (IML) is a rare disorder of small and medium size vessels that frequently goes undiagnosed until the time of autopsy. The clinical courses of two such patients were examined to determine factors that would facilitate antemortem diagnosis. Both patients had mental status changes, pyramidal tract signs, and peripheral neuropathy. Despite postmortem evidence of widespread lymphocytic invasion of vessels throughout the body including peripheral and central nervous systems, neuroimaging studies, cerebrospinal fluid analysis, peripheral blood studies, and bone marrow biopsy failed to reveal diagnostic evidence of the underlying neoplastic process. Although markedly abnormal, nerve conduction studies were nonspecific. Familiarity with IML and its consideration in the differential diagnosis when central and peripheral nervous system dysfunction occur concurrently may guide the physician to tissue biopsy facilitating antemortem diagnosis and institution of appropriate therapy.  相似文献   

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Intravenous administration of liposome-encapsulated hemoglobin (LEH) in rats led to an early (within 15 min) decline of hemolytic complement (C) activity in the plasma along with a significant, parallel rise in thromboxane B2 (TXB2) levels. The TXB2 response was inhibited by co-administration of soluble C receptor type 1 (sCR1) with LEH, as well as by C depletion with cobra venom factor. These observations provide evidence for a causal relationship between LEH-induced C activation and TXB2 release, and suggest that sCR1 could be useful in attenuating the acute respiratory, hematological and hemodynamic side effects of LEH described earlier in the rat.  相似文献   

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The poor survival rate for patients with regional lymph node metastases of malignant melanoma reflects the strong association between lymph node and subsequent visceral metastases. The authors discuss clinical considerations, pathologic risk factors, selective lymphadenectomy, examination of lymph node dissections, difficulties of diagnosis, and prognosis.  相似文献   

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Malignant histiocytosis (MH)-like B-cell lymphoma (BCL) is a neoplastic proliferation of large B cells clinically characterized by fever, hepatosplenomegaly, haemophagocytosis and abnormal laboratory data, without lymphadenopathy or skin lesions. Interestingly, most cases have been reported in Asian patients, and it is unclear whether MH-like BCL is biologically distinct from conventional large B-cell lymphomas. We report five Japanese patients with MH-like BCL. Biopsied specimens of bone marrow, liver and/or spleen showed infiltration of neoplastic B cells accompanied by haemophagocytosing histiocytes. Lymphoma cells were positive for CD19, CD20 and HLA-DR surface antigens, and negative for CD5 and CD10. In four cases elevated serum levels of interleukin (IL)-6 and the soluble IL-2 receptor isoform were noted, but not IL-1beta, IL-2 or tumour necrosis factor-alpha. Autopsies of two cases were pathologically diagnosed as intravascular lymphomatosis (IVL). Based on these observations, the current and nine previous cases reported as MH-like BCL in Japan were re-evaluated. They appear to form a peculiar variant of IVL, characterized by bone marrow involvement at presentation, haemophagocytic syndrome, and a rapidly aggressive clinical course, but rarely neurological complications or skin lesions. This variant may merit separate consideration because of the problems posed in the initial diagnosis and therapeutic approaches.  相似文献   

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A 94-year-old man who had been admitted to our hospital for the treatment of senile dementia and restless behavior exhibited consciousness disturbances, acute respiratory failure, high fever, and thrombocytopenia the day after receiving haloperidol as prescribed by a psychiatrist. On the fourth day following administration of haloperidol, acute renal failure with rhabdomyolysis and disseminated intravascular coagulation (DIC) developed in the patient, who was accordingly given a diagnosis of haloperidol-induced neuroleptic malignant syndrome (NMS) associated with DIC. He was then given heparin and antithrombin III, and his DIC symptoms improved soon thereafter. Elevated plasma levels of tissue factor and tumor necrosis factor-alpha (TNF-alpha) were sustained during this therapy course. Other cytokines, including interleukin IL-1 beta, IL-2 and IL-6, were not elevated. There are activation of extrinsic coagulation and an elevated level of TNF-alpha during acute renal failure and rhabdomyolysis associated with NMS, which is thought to trigger the onset of DIC.  相似文献   

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The diagnosis of disseminated intravascular coagulation associated with intracranial pathology is discussed. This pathological entity is characterized by a diffuse bleeding diathesis. Laboratory studies suggest a consumption of all clotting and fibrinolytic factors with an elevation of fibrin split products as a sign of the fibrinolytic activity. The treatment consists of the administration of packed platelets and fresh frozen plasma to replace the consumed coagulation factors. Heparinization is recommended early to prevent further consumption of coagulation factors and epsilon-aminocaproic acid is recommended later after acute fibrinolysis is diagnosed. Constant coaguloanalytic monitoring is necessary. Although the etiology with massive injury to brain tissue is possibly secondary to autotransfusion of brain tissue thromboplastin, other causes such as hypotension, anoxia, acidosis and hemolysis must be considered.  相似文献   

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The variations of the measured dose rate in air should be recognized especially where background radiation is used as a comparative benchmark to assess radiation surveillance and environmental remediation work. In this note, the natural variations of the combined gamma and cosmic-ray background air-dose rate as measured by lithium fluoride thermoluminescence dosimeters are reported. The dosimeters were deployed monthly at locations within 150 km of the Environmental Measurements Laboratory in New York City. Urban and suburban stations were established with simultaneous indoor and outdoor measurements at some locations. Measurements were obtained over 10 to 18 years. The mean air-dose rates from the six outdoor and four indoor stations vary from 50.8 to 123.1 nGy h(-1). The range of the annual dose rates expressed as a percent-difference of the minimum and maximum is 5.3 to 18.0%. Commonly, 1-mo deviations from the long term mean of about +/-10 to +/-25% are observed. An abrupt decrease in the annual dose rate at one of the measurement sites was attributed to a minor relocation of a dosimeter. Structural shielding factors for the first and second floors of a residence are reported. The ground level location of a dosimeter inside another residence apparently resulted in a very high shielding factor. Finally, a gradual decrease of the dose rate at most of the stations is shown to exist (approximately -0.3 nGy h(-1) y(-1) for the outdoor stations). Plausible causes of this trend are briefly discussed.  相似文献   

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The colonization of gastric mucosa by Helicobacter pylori (H.p.) is a special form of chronic bacterial infection characterized by long term persistence of microbes because cause of an inefficiency of local immune responses. The resulting chronic gastritis causes decisive transformations of gastric mucosa. They comprise the acquisition of an active mucosa-associated lymphoid tissue as well as the development of glandular atrophy and intestinal metaplasia in the stomach. Both transformations change normal gastric functions, and create abnormal microenvironments with an increased risk for gastric cancer and lymphoma. Own recent investigations indicate, that the distribution and severity of chronic gastritis might be decisively influenced by a rise of antigastric autoimmune reactivity during the H.p. infection. The histologic examination of gastric biopsy samples is essential for an exact diagnosis of the complex pathogenic processes in chronic gastritis. In the future special emphasis of histologic analyses has to be put on the subtypes of gastritis, which are prone for complications and on the evaluation of gastritis remission after H.p. eradication.  相似文献   

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This review focuses on infertility-related anatomical (ligneous cervicitis and postsurgical stenosis) and functional (abnormal mucus production, local cervical isoimmunity, and incompetence) disorders of the cervix, congenital anomalies, and underperfusion of the uterine corpus, myometrial lesions, endometrial failure, tubal obstruction, polycystic ovary syndrome, and endometriosis.  相似文献   

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