Intranuclear localization of Plasmodium berghei sporozoites.
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Animals↗
Biomedical subjects
J F Meis
Publications and source records attributed to J F Meis.
Fine structure of Plasmodium berghei exoerythrocytic forms in cultured primary rat hepatocytes.
Sporozoites of the rodent malaria parasite Plasmodium berghei have been grown in primary cultures of hepatocytes from Brown Norway rats. The ultrastructure of in vitro grown exoerythrocytic forms was compared with that of parasites in vivo. Peculiar vesicles, previously not described in vivo, were identified and their possible origin is discussed. Otherwise, the fine structure of the hepatocytic stages grown in vitro was shown to be grossly similar to those in vivo. Therefore, electron microscopy of cultured exoerythrocytic parasites will contribute to the understanding of the cell biology and drug sensitivity of this elusive stage.
Animals↗
An ultrastructural study on the role of Kupffer cells in the process of infection by Plasmodium berghei sporozoites in rats.
The interactions in vivo between Plasmodium berghei sporozoites and Kupffer cells in rat livers were studied by transmission electron microscopy. By 10 and 15 min after inoculation, sporozoites were both free in the liver sinusoids and inside endocytotic vacuoles of the Kupffer cells. The latter cells were very active in phagocytosing sporozoites, bacteria and red blood cells. The sporozoites retained their integrity inside the endocytotic vacuoles and no signs of lysosomal digestion were observed. Sporozoites seen within endocytotic vacuoles 1 h after inoculation were still morphologically intact, although bristle-coated vesicles fused with the vacuole membrane. Evidence is presented which suggests that Kupffer cells transport sporozoites towards the space of Disse and adjacent hepatocytes. No sporozoites were seen to penetrate an endothelial cell or its narrow fenestrae. It is proposed that Kupffer cell passage, rather than gaps in the sinusoidal lining, represents the normal route that sporozoites take to circumvent the endothelial barrier. The localization of exo-erythrocytic forms was made easier by the use of Brown Norway rats in which many more parasites develop than in the Wistar rats. The distribution pattern of the parasites was found to be mainly around the 'periportal' zones of the acini of liver tissue.
Animals↗
Ultrastructural studies of a vesicle system associated with endoplasmic reticulum in exo-erythrocytic forms of Plasmodium berghei.
Fine structural studies of a specialized vesicle system associated with the endoplasmic reticulum (ER) of exo-erythrocytic Plasmodium berghei suggest that this system may be the equivalent of a Golgi apparatus. Patches of ER, randomly distributed in the cytoplasm of developing parasites, are formed of smooth and ribosome-studded cisternae intermingled with each other. The vesicle systems are located between as well as at the edges of ER aggregates and appear to be in different stages of budding from the cisternae. Prolonged osmication reveals distinct staining of the nuclear envelope and ER of the parasites as well as part of the Golgi apparatus of the hepatocytes. However, the small vesicles associated with the parasite's ER are unstained, as are the coated vesicles in the Golgi region of the liver cell. These sites in the parasite cytoplasm seem comparable to the concave surface of the Golgi apparatus in liver cells. The pinched-off vesicles fuse with others to form the prominent peripheral vacuolization characteristic of the nearly mature exoerythrocytic form. The formation of these peripheral vacuoles and their subsequent fusion with the parasite membrane may be an exocytosis mechanism supplying the rapidly expanding parasite with new plasma membrane material.
Animals↗
Ultrastructural observations on the infection of rat liver by Plasmodium berghei sporozoites in vivo.
The invasion of liver parenchymal cells by sporozoites of Plasmodium berghei Vincke & Lips, 1948, was studied in vivo using transmission electron microscopy. Livers of Brown Norway rats were examined 30 and 60 min after intraportal injection of 15 million sporozoites each. Sporozoites found after incorporation into vacuoles in hepatocytes were often located near a bile canaliculus at the lateral cell surface, surrounded by hepatocyte lysosomal structures; however, degradation of sporozoites caused by lysosomal digestion inside hepatocytes was never observed. Due to the crescent shape of sporozoites, serial sections were necessary to demonstrate the actual process of invasion of the hepatocyte. The hepatocyte's plasmalemma appeared to invaginate due to the sporozoite's action, thereby creating a parasitophorous vacuole. It was suggested that the sporozoite actively penetrated the hepatocyte; however, no visible depletion of rhoptries and micronemes was observed.
Animals↗
The demonstration of Plasmodium berghei sporozoites in rat hepatocytes one hour after inoculation.
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Animals↗
Degenerating exo-erythrocytic forms of Plasmodium berghei in rat liver: an ultrastructural and cytochemical study.
Morphological and cytochemical aspects of the host response to almost mature exo-erythrocytic forms (EEF) of Plasmodium berghei in rat hepatocytes were studied by electron microscopy. Young stages (less than 47 h) never evoked a local reaction. Two types of nearly mature EEF (47-51 h) could be distinguished, normal (EEF type I) and those that were the target of infiltrating cells (EEF type II). The latter were in a stage of early or advanced degeneration and generally exhibited increased electron density, especially in the contents of their peripheral vacuoles. Neither type of EEF exhibited detectable enzyme activity, although host cell enzymes, such as peroxidase and 5-nucleotidase, were demonstrable. However, the infected liver cell appeared permeable to ruthenium red whereas non-infected hepatocytes were not. When signs of degeneration were present, as shown by the increasing density of the cytoplasm, loss of enzyme activities occurred. The encompassing mononuclear cells were identified as true monocytes, non-monocyte-derived and monocyte-derived macrophages by their endogenous peroxidase activity. Macrophage filopodia penetrated and cleaved both hepatocyte and parasite cytoplasms. Subsequently, digestion and clearing of the remnants took place. This study clearly demonstrated that a proportion of the intra-hepatocytic EEF was destroyed by macrophages before they were able to mature completely and release their merozoites.
Animals↗
An ultrastructural study of developing stages of exo-erythrocytic Plasmodium berghei in rat hepatocytes.
The ultrastructure of immature exo-erythrocytic forms of Plasmodium berghei in rat hepatocytes was studied at stages between 25 and 51 h of development. A new method was successfully applied to localize the parasites in a small portion of the liver by temporary ligature of blood vessels to the majority of the liver, and from the spleen and the pancreas. Nuclear profiles appeared to be part of a highly lobed nuclear reticulum. Peripheral vesiculation and vacuolization of the cytoplasm was increasingly prominent and ushered in the formation of pseudocytomeres. Spacing between host- and parasite-derived membranes could first be observed after 43 h of development. In general, organellar development was found to follow closely that described for plasmodial oocysts.
Animals↗
Multiple brain abscesses and bacteremia in a child due to Fusobacterium necrophorum.
A case of Fusobacterium necrophorum bacteremia and multiple brain abscesses in a 6-year-old child following a Mycoplasma pneumoniae infection is described. Brain abscess due to this microorganism has only been described in three other cases since 1977. The clinical picture was consistent with postanginal septicemia, with septic metastatic complications normally only seen in teenagers and young adults. The patient was successfully treated with a 2-month course of parenteral penicillin G and metronidazole.
Bacteremia↗
Rapidly fatal Q-fever pneumonia in a patient with chronic granulomatous disease.
Acute Q-fever is a systemic illness which rarely has a fatal outcome. Fatal cases do occur with the chronic form of the disease and associated with endocarditis. This report presents the case of a fatal, acute Q-fever pneumonia in an 11-year-old patient with chronic granulomatous disease. Complement fixation antibody titer rose to 1:1,024 with positive IgM in immunofluorescence. Giemsa stained lung sections and indirect immunofluorescence demonstrated the microorganisms in the tissues. The Coxiella burnetii infection was probably contracted during a holiday trip to rural France. Despite the fact that the patient received a variety of antimicrobial agents with broad spectrum activity against bacteria and fungi, coverage for Q-fever, i.e. chloramphenicol or tetracyclines, was not included.
Anti-Bacterial Agents↗
Epidemiological survey of an outbreak of multiresistant Serratia marcescens by PCR-fingerprinting.
During an outbreak of Serratia marcescens from May to November 1993 43 strains obtained from 27 ICU patients infected or colonized with multiresistant S. marcescens were genotypically characterized with random amplified polymerase chain reaction (RAPD-PCR)-fingerprinting. In addition, 43 epidemiologically unrelated control isolates were selected. PCR-fingerprinting identified ten different genotypes of S. marcescens among the outbreak related strains. One predominant genotype was demonstrated in 21/43 isolates of 11/27 patients. A cluster of this genotype was found in seven/eight patients on the cardiosurgical ICU. The epidemiologically unrelated strains all showed different genotypes as compared to the predominant type. This survey proved RAPD-PCR to be a highly discriminatory and reproducible method for epidemiological studies of S. marcescens strains in nosocomial outbreaks.
Bacterial Typing Techniques↗
Amphotericin B versus amphotericin B plus 5-flucytosine: poor results in the treatment of proven systemic mycoses in neutropenic patients.
Twenty-eight neutropenic (< 500 granulocytes/microliters) adults with microbiologically or histologically proven systemic mycosis were randomly assigned to receive either amphotericin B alone (0.5 mg/kg/day; n = 14) or amphotericin B (0.5 mg/kg/day) plus 5-flucytosine (150 mg/kg/day; n = 14) intravenously. Therapy was given for an average duration of 10 days in both groups, amounting to a total dose of amphotericin B of 338 mg and 308 mg, respectively. The mean duration of granulocytopenia was 18 days in the amphotericin B group and 20 days in the combination group. Only two patients treated with amphotericin B alone and three given the combination survived. Adverse events were similar in both groups with an elevation of the serum creatinine in six cases during the administration of amphotericin B alone and in seven cases treated with the combination. No other serious adverse events were encountered. Treatment with both regimens was disappointing partly because mycosis was too far advanced by the time therapy was begun and neutrophils were recovered in only half the patients.
Adult↗
Pneumopericardium complicating invasive pulmonary aspergillosis: case report and review.
Pneumopericardium, the presence of air in the pericardial space, is a rare disorder that is usually caused by trauma. We describe a patient given induction chemotherapy for acute myelogenous leukemia who developed pulmonary aspergillosis that resulted in pericarditis and pneumopericardium. He responded to antifungal treatment and recovered from granulocytopenia, but died early during the next course of chemotherapy. Two other reported cases of pneumopericardium associated with pulmonary aspergillosis are summarized.
Adult↗
Fluconazole in the management of fungal urinary tract infections.
The presence of Candida in the urine is not considered normal but does not necessarily indicate urinary tract infection. On the other hand, yeasts in urine cultures might be the first symptom of systemic fungal infections. Despite the difficulties that exist, establishment of an accurate diagnosis is important especially in high risk patients because ascending infections may lead to disseminated disease. Amphotericin B bladder irrigation is a common mode of therapy for fungal urinary tract infection, although no specific guidelines exist as to the use of the procedure. The pharmacokinetic parameters possessed by the triazole antifungal agent fluconazole make it a candidate for treating fungal urinary tract infections. Five case reports and 99 patients reported in several small studies were reviewed. As evident from these reports, fluconazole appears to be of value in the treatment of both uncomplicated and complicated fungal urinary tract infections.
Candidiasis↗
Endophthalmitis as presenting symptom of group G streptococcal endocarditis.
Group G streptococci can cause serious infections in patients with predisposing factors. Involvement of the eye has rarely been reported in patients without ocular history. Two cases of group G streptococcal endocarditis which presented with an endogenous endophthalmitis are reported. Topical and systemic antimicrobial therapy resulted in recovery, but visual outcome was poor.
Aged↗
Candidemia in intensive care unit patients: risk factors for mortality.
Aim of this study was to evaluate whether risk factors which predict the development of candidemia may also predict death in ICU patients with candidemia. During an 8-year-period all ICU patients whose blood cultures yielded Candida species (n = 40) were retrospectively evaluated in a case-control fashion. The average incidence of Candida bloodstream infections was 5.5 per 10,000 patient days, ranging from 2.4 in 1990 to 7.4 in 1994. C. albicans was the most common pathogen in candidemic patients, but the proportion of non-C. albicans strains showed an increasing trend during 1989-1993, with a major shift towards non-C. albicans species in 1994. The overall mortality of patients with candidemia was 58%. Mortality was highest in the group of patients with multi-organ dysfunction syndrome, especially among those in need of hemodialysis. Risk factors for the development of candidemia, such as age, malignancy, steroid use, i.v. catheterization, and the use of broad-spectrum antibiotics were not correlated with mortality in the ICU patients studied.
Candida↗
Serial monitoring of Aspergillus antigen in the early diagnosis of invasive aspergillosis. Preliminary investigations with two examples.
A recently developed sandwich ELISA, which detects Aspergillus galactomannan, was tested retrospectively in serial serum samples from an allogeneic bone marrow transplant recipient with proven invasive aspergillosis (patient 1) and another with suspected disease (patient 2). Galactomannan was detected in the serum 4 and 28 days, respectively, before pulmonary infiltrates suggestive of fungal infection first became apparent on the chest X-ray. Aspergillus was detected by ELISA and PCR in BAL fluid samples from both patients, and in CSF from patient 1. The diagnosis was confirmed at autopsy for patient 1 by histopathology and the recovery of Aspergillus fumigatus from the lung and brain. Furthermore, in both patients the course of the antigen titer in the serum during antifungal treatment corresponded with the clinical outcome. These results confirm that the sandwich ELISA appears to be useful for the early diagnosis of invasive aspergillosis. The value of the test for monitoring the response to antifungal treatment remains to be established in prospective trials.
Adult↗
Candida tropicalis arthritis in a patient with acute myeloid leukemia successfully treated with fluconazole: case report and review of the literature.
The case of a 77-year-old woman with acute myeloid leukemia who developed Candida tropicalis septic arthritis of the knee after remission-inducing chemotherapy is reported. A literature review of C. tropicalis non-prosthetic arthritis is included. The isolate was susceptible to fluconazole (MIC 0.25 mg/l). She was treated with fluconazole (400 mg orally) and frequent relieving synovial aspirations. After 1 month of antifungal therapy the synovial fluid became culture negative. Fluconazole concentration in the synovial fluid and serum were 20 mg/l and 19.4 mg/l, respectively. The patient was treated for a total of 7 months and made a full recovery. This is the first report of the successful use of fluconazole in the treatment of septic arthritis due to C. tropicalis.
Aged↗