Pulmonary microsporidiosis due to Encephalitozoon hellem in a patient with AIDS

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.

First isolation and characterization in humans of Entamoeba histolytica (laboratory-made) zymodeme XX

Isoenzyme analysis by starch-gel electrophoresis has proved to be a useful method for the biochemical differentiation of pathogenic Entamoeba histolytica and non-pathogenic E. dispar isolates. Of the known 24 zymodemes, 3 are laboratory-made and have not previously been identified in humans. Parasitology screening was carried out in a psychiatric institution. Two amebic stocks were isolated and characterized that had never previously been found in humans and that have protein patterns identical to that of the laboratory-made zymodeme XX.

Schnitzler's syndrome: report of a new case and a review of the literature

Schnitzler syndrome is a rare condition characterized by chronic non-pruritic urticaria, recurrent fever, bone pain, osteocondensation, and monoclonal IgM gammopathy without features of lymphoproliferative disease. We describe the case of a 44-year-old man with an 8-year history of bone pain with hyperostosis and a 5-year history of chronic non-pruritic urticaria, associated with fever, hyperleukocytosis, hepatomegaly, serum monoclonal IgM-kappa. Systemic treatment with steroids was effective against bone pain but was ineffective in controlling the urticaria. We also review 35 cases. No adequate treatment has yet been found. The pathogenesis is unclear and the role of the IgM component in the induction of urticaria has not been established.

[Aneurysm of the popliteal artery. A case contribution of a 15-year surgical experience]

This retrospective study involves 45 patients operated in the years 1980-1994 for popliteal artery aneurysms with a posterior approach. The number of aneurysms is 60 because 15 were bilateral; 18 patients presented a polianeurysmatic involvement of the arterial tree. In 14 cases the intervention were performed on asymptomatic patients, in 46 cases the patients were symptomatic for ischemic disease. The reconstructive interventions were performed on 58 cases and only in 2 cases the medial approach to popliteal vessel were preferred on the basis of the great dimension of the aneurysms which involved also the superficial femoral artery. PTFE grafts were adopted in 33 cases, saphenous vein in 19 cases and Dacron grafts in 5 cases. We had no perioperative mortality and 4 patients died for causes not correlated to the intervention. We had perioperative complication in the group of asymptomatic patients. In the group of symptomatic patients 5 underwent a major amputation. The global patency of these grafts is 86% after 10 years. The posterior approach to the popliteal vessels has the advantage of a better view of the aneurysmatic mass and the anatomic structures and it permits a direct end graft. This graft is usually shorter than in the case of the medial approach and cannot be compressed by the aneurysmatic mass.

Madin Darby canine kidney: a new cell line for Pneumocystis carinii in vitro culture

Pneumocystis carinii pneumonia (PCP) is a highly frequent cause of morbidity and mortality in immunocompromised subjects, particularly in HIV-infected ones. The biology of P. Carinii is poorly understood because of the lack of reliable synthetic media or adequate cell lines to grow this opportunistic pathogen in continuous culture. We reported the suitability of the MDCK (Madin Darby Canine Kidney, ATTC CCL 34) cell line to support the temporary microorganism's growth in vitro and the experimental pharmacological trials, in comparison with the HEL 299 cell line, used as reference standard.

Microsporidian spore wall: ultrastructural findings on Encephalitozoon hellem exospore

A study of the spore wall of Encephalitozoon hellem was performed on thin sections, freeze-fracture, and deep-etched samples to obtain information on spore wall organization and composition. Our observations demonstrate that the spore wall is formed by an inner 30-35 nm electron-lucent endospore and an outer 25-30 nm electron-dense exospore. The exospore is a complex of three layers: an outer spiny layer, an electron-lucent intermediate lamina and an inner fibrous layer. Freeze-fracture and deep-etching techniques reveal that the intermediate lamina and the inner fibrous layer result from the different spatial disposition of the same 4-nm thick fibrils. In thin sections the endospore reveals a scattered electron-dense material that appears in the form of trabecular structures when analyzed in deep-etched samples. The presence of chitin in the exospore is discussed.

Direct sequencing of the PCR amplified SSU rRNA gene of Entamoeba dispar and the design of primers for rapid differentiation from Entamoeba histolytica

Since 1993, strains of Entamoeba histolytica sensu lato have been assigned to 2 species on the basis of clinical, biochemical, immunological and genetic evidence: the pathogenic strains to E. histolytica sensu stricto, the non-pathogenic strains to Entamoeba dispar. Analysis of the gene encoding for the small subunit ribosomal RNA (SSU rDNA) supports the existence of 2 species. However, while 3 whole SSU rDNA sequences are available in the data bases for E. histolytica, only a partial sequence has been published for E. dispar. Here we report a SSU rDNA sequence for E. dispar. Compared to those of E. histolytica, this sequence shows 1.7% nucleotide substitutions. On the basis of our rDNA data, 2 primers were designed to produce polymerase chain reaction (PCR) amplification from both E. histolytica and E. dispar. Primer specificity for the 2 amoebae was assessed both theoretically against the data bases, and experimentally against a collection of eukaryotic and prokaryotic DNAs. The amplified stretch encompasses a polymorphic Dde I restriction site which allows, after cleavage of the fragment, E. histolytica and E. dispar to be distinguished. The reliability of this method of identification was assessed comparing the results with those based on classic isoenzyme analysis.

Subchronic glucocorticoid pretreatment reversibly attenuates IL-beta induced fever in rats; IL-6 mRNA is elevated while IL-1 alpha and IL-1 beta mRNAs are suppressed, in the CNS

Subchronic (36 h) exposure of rats to corticosterone (CS) (100 mg/pellet,subcutaneously), blocked the pyrogenic response to recombinant human interleukin 113 (rhIL-1 beta, 5 mu g/kg, ip.). CS treatment reduced the basal mRNA levels of IL-1 alpha and IL-1 beta, but elevated the mRNA levels of IL-6 in the hypothalamus and hippocampus as shown by RT-PCR. The CS treatment clamped the cytokine mRNA levels, and injection of rhIL-1 beta to CS treated rats did not significantly affect these altered mRNA levels. IL-6 bioactivity in serum was not significantly changed by CS treatment, but increased 50 times upon injection of rhIL-1 beta. rhIL-1 beta caused a significantly lower induction of serum IL-6 levels in CS pretreated rats (9-fold). The pyrogenic response to injection of rhIL-1 beta has returned 5 days after the removal of the corticosterone pellet, and the hypothalamic cytokine mRNA levels (IL-1 alpha, IL-1 beta and IL-6) have returned to basal. These results suggest that altered and clamped hypothalamic IL-1 alpha, IL-1 beta and IL-6 mRNA levels may be involved in the antipyretic effects of a pretreatment with high doses of CS and that these CS effects are rapidly reversible.

Interleukin (IL)-6 gene expression in the central nervous system is necessary for fever response to lipopolysaccharide or IL-1 beta: a study on IL-6-deficient mice

Interleukin (IL)-6, IL-1 beta, and tumor necrosis factor alpha (TNF-alpha) are considered to act as endogenous pyrogens. Because of the complex pattern of cross-inductions between these cytokines, the relative role of the central and peripheral production of these cytokines in eliciting the fever response has not yet been clarified. The purpose of this study was to determine the role of IL-6 in the fever response by making use of mice carrying a null mutation in the IL-6 gene. The intraperitoneal injections of lipopolysaccharide (LPS) (50 micrograms/kg) and recombinant murine (rm) IL-1 beta (10 micrograms/kg), respectively, failed to evoke fever response in IL-6-deficient mice, whereas the same doses of LPS and rmIL-1 beta caused fever response in wild-type mice. The fever response could be induced in the IL-6-deficient mice by intracerebroventricular injection of recombinant human (rh) IL-6 (500 ng/mouse), whereas intracerebroventricular injection of rmIL-1 beta (100 ng/mouse) failed to produce fever response in the IL-6-deficient mice. These results suggest that central IL-6 is a necessary component of the fever response to both endogenous (IL-1 beta) and exogenous (LPS) pyrogens in mice and that IL-6 acts downstream from both peripheral and central IL-1 beta.

Transmission of Entamoeba histolytica within a family complex

A limited outbreak of symptomatic intestinal and extraintestinal amoebiasis within a family complex is described. The infection was almost certainly transmitted by a Philippino housemaid, who was an asymptomatic carrier of Entamoeba histolytica infection acquired in her native country. Starch-gel electrophoresis showed isoenzyme patterns characteristic of pathogenic zymodeme XIX in all the amoebic isolates.

Magnetic resonance (MR) imaging and MR spectroscopy of nerve regeneration and target muscle energy metabolism in a model of prosthesis-guided reinnervation in rats

RATIONALE AND OBJECTIVES

We monitored the regeneration of the rat sciatic nerve after its transection and the concomitant alteration in the high-energy phosphates content in the target tibialis anterior muscle.

METHODS

Rat sciatic nerve was resected and the gap connected with a prosthesis of polytetrafluoroethylene. Progress of reinnervation was monitored by 1H MR imaging, whereas muscular energy metabolism was evaluated by localized 31P MR spectroscopy.

RESULTS

Reconstitution between the nerve stumps was resumed 8-12 weeks postoperatively. The ratio of phosphocreatine to inorganic phosphate reached a plateau at 46% of the initial level approximately 8 weeks after the operation and recovered thereafter. Immediately after the surgery, muscular pH became slightly alkaline and returned to normal with the progress of reinnervation.

CONCLUSION

Recovery of the muscular energy metabolism began after the reconnection of the severed nerve stumps. The combination of MR imaging and MR spectroscopy followed noninvasively the progress of reinnervation and muscular energy metabolism of the prosthesis-guided nerve regeneration.