Tuberculosis in Australia--a forgotten disease.
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Australia↗
Biomedical subjects
R Lumb
Publications and source records attributed to R Lumb.
Mycobacterium bovis (BCG) vaccination. Progressive disease in a patient asymptomatically infected with the human immunodeficiency virus.
OBJECTIVE: To report a case of progressive disease caused by Mycobacterium bovis after BCG vaccination in a patient asymptomatically infected with the human immunodeficiency virus (HIV). CLINICAL FEATURES: A 34-year-old white man about to commence employment as a developmental care worker had a BCG vaccination. Five months later, he had a positive result to a serological test for HIV antibody. Nine months after BCG vaccination, he presented with fever (38.7 degrees C), a large left axillary lymph node and a small left pleural effusion. The lymph node was biopsied and acid-fast bacilli observed in Ziehl-Neelsen stained smears. Culture grew Mycobacterium bovis (BCG). TREATMENT AND OUTCOME: He was successfully treated with isoniazid, rifampicin and ethambutol for a period of nine months. CONCLUSION: BCG vaccination of asymptomatic HIV-positive patients is not recommended. The detection of those at risk for HIV infection before vaccination administration is essential. Self-exclusion based on information supplied to all potential recipients is likely to be the most effective method.
Adult↗
Isospora belli infection. A report of two cases in patients with AIDS.
OBJECTIVE: To present the findings of Isospora belli infection in two patients with the acquired immunodeficiency syndrome (AIDS). CLINICAL FEATURES: One patient was part Aboriginal, the other an immigrant recently arrived from Peru. Both men were infected with the human immunodeficiency virus (HIV). They presented with watery diarrhoea, one with severe weight loss. Isospora belli oocysts were detected in multiple faecal specimens from both patients. One patient had a concomitant infection with Cryptosporidium sp. INTERVENTION AND OUTCOME: There was a rapid response to treatment with cotrimoxazole (960 mg, four times a day for 10 days). A complete response was obtained in the patient with concurrent cryptosporidiosis. The diarrhoea recurred after cessation of treatment, necessitating maintenance therapy. CONCLUSION: Although Isospora belli is an uncommon cause of gastroenteritis in Australia, it is increasingly recognised as a cause of diarrhoea in travellers, immigrants from endemic areas and immunocompromised people. It has also been reported in the Aboriginal community; this article reports the first case of AIDS-related isosporiasis in an Aborigine. It is likely that both patients acquired Isospora belli before they become HIV seropositive.
Acquired Immunodeficiency Syndrome↗
Antigenic characterisation of monoclonal antibodies against Sarcocystis muris by western blotting and immuno-electron microscopy.
The antigenic specificities of 13 monoclonal antibodies (mAbs) raised against Sarcocystis muris cystozoites were examined by Western blotting and immuno-electron microscopy against homologous S. muris and heterologous S. gigantea, S. tenella, S. arieticanis, S. capracanis, S. miescheriana and Toxoplasma gondii antigens. Four mAbs reacted in Western blots against S. muris antigens: SM-4 and -17 recognized single antigenic bands (31,000 and 34,000 MW, respectively) and SM-2 and -3 reacted against multiple bands (ranging from 12,500-30,000 and 13,000-50,000 MW, respectively). Similar antigens were also recognized by polyclonal immune sera from chronically infected mice. None of the mAbs cross-reacted with heterologous Sarcocystis spp. or T. gondii. Ultrastructural studies performed with colloidal-gold conjugates demonstrated that three mAbs reacted with specific antigenic elements in S. muris cystozoites: SM-3 and -4 labelled pellicular determinants and SM-19 labelled micronemes. None of the mAbs cross-reacted with heterologous Sarcocystis spp., whereas polyclonal immune sera from chronically infected sheep, goats and pigs cross-reacted with a variety of antigens in all Sarcocystis spp. except the primary cyst-wall determinants.
Animals↗
Subcellular localization of enzymes related to PAF metabolism in Krebs-II ascites cells: evidence for the lack of intracellular PAF transfer activity.
We have investigated various steps in the metabolism of Platelet-Activating Factor (PAF-acether or PAF) at the subcellular level in Krebs-II ascites cells. Microsomes contained an active acetyltransferase located on a heavy-rough domain of the endoplasmic reticulum quite rich in ribosomes, as monitored by [3H]uridine labelling, and which displayed a very high density across the Percoll gradient. This membrane domain, which was separated from all other cellular organelles including peroxisomes, also contained a membrane-bound acetylhydrolase with similar activity as the acetyltransferase. However most part of the cellular acetylhydrolase was located in the cytosol, which was actually devoid of PAF transfer activity, normally involved in transport of the mediator within the cell.
Acetyltransferases↗
Phylogenetic relationships of Cryptosporidium determined by ribosomal RNA sequence comparison.
Reverse transcription of total cellular RNA was used to obtain a partial sequence of the small subunit ribosomal RNA of Cryptosporidium, a protist currently placed in the phylum Apicomplexa. The semi-conserved regions were aligned with homologous sequences in a range of other eukaryotes, and the evolutionary relationships of Cryptosporidium were determined by two different methods of phylogenetic analysis. The prokaryotes Escherichia coli and Halobacterium cuti were included as outgroups. The results do not show an especially close relationship of Cryptosporidium to other members of the phylum Apicomplexa.
Animals↗
Characterization of monoclonal antibodies against ovine Sarcocystis spp. antigens by immunoblotting and immuno-electron microscopy.
Six monoclonal antibodies were raised in mice against purified cytozoite extracts of Sarcocystis gigantea and S. tenella from sheep. Each monoclonal antibody was evaluated for specificity by enzyme immunoassay, immunoblotting and immuno-electron microscopy using homologous and heterologous antigenic preparations. All six monoclonal antibodies exhibited good species-specificity when reacted against crude soluble cystozoite antigens in enzyme immunoassays. However, only two monoclonal antibodies (IgM and IgG2a) exhibited reactivity in Western blots against specific protein bands. Both reacted against S. gigantea antigens of 100,000, 43,000 and 39,000 molecular weight. Neither monoclonal antibody reacted against the heterologous species S. tenella. Ultrastructural studies performed with colloidal-gold conjugated antisera revealed that both monoclonal antibodies reacted against antigens located around micronemes and amylopectin granules in S. gigantea cystozoites. Another monoclonal antibody (IgGI) reacted only against microneme determinants in S. tenella cystozoites. In contrast, polyclonal sheep and rabbit immune sera cross-reacted against a wide range of cystozoite antigens.
Animals↗
A prospective hospital study of the aetiology of community-acquired pneumonia.
In a one-year prospective study of 106 adults (mean age, 60 years) who were admitted to hospital with community-acquired pneumonia, an aetiological diagnosis was made in 82 (77%) patients. Streptococcus pneumoniae was considered to be responsible for 44 (42%) and respiratory viruses for 19 (18%) infections. Other aetiological agents that were found in a smaller number of patients included Haemophilus influenzae (9% of patients), enteric Gram-negative bacilli (8% of patients), Staphylococcus aureus (3% of patients), Legionella spp. (3% of patients), Mycobacterium tuberculosis (3% of patients), Mycoplasma pneumoniae (8% of patients) and Chlamydia psittaci (5% of patients). The mortality was 10% and was related significantly to increasing age and to coexisting heart and lung disease. Antibiotic treatment that was commenced before admission to hospital and investigations were undertaken reduced significantly the isolation rate of susceptible bacterial pathogens. The Gram-stained smear of sputum was valuable in establishing a tentative diagnosis of bacterial pneumonia. The most-useful tests in making an early diagnosis proved to be those which detected pneumococcal and mycoplasmal antigens, blood cultures and culture of sputum for appropriate bacterial pathogens.
Adolescent↗
Localization of a 23,000 MW antigen of Cryptosporidium by immunoelectron microscopy.
Rabbit antiserum was raised against a 23,000 molecular weight (MW) antigen prepared from Cryptosporidium oocysts by electro-elution from polyacrylamide gels. The antiserum was tested for specificity by immunoblotting against solubilized oocyst preparations. Several antigens including the 23,000 MW antigen were recognized suggesting that it shared common epitopes with higher MW proteins. The antiserum was then used in conjunction with a protein A-colloidal gold conjugate to locate antigenic sites within exogenous and endogenous developmental stages of Cryptosporidium. The pellicles of both sporozoites and merozoites exhibited specific labelling, particularly around their anterior ends. No specific labelling was observed for any other membrane determinants or organelles in these or other life cycle stages.
Adult↗
Ultrastructure of the attachment of Cryptosporidium sporozoites to tissue culture cells.
The attachment of Cryptosporidium sporozoites to Madin-Darby canine kidney (MDCK) cells was examined using transmission electron microscopy. As the anterior end of the sporozoite came into close proximity to the MDCK cell, the host cell membrane evaginated around the sporozoite, forming a parasitophorous vacuole. A dense band formed below the host cell membrane at the site nearest to the conoid. Variably electron-dense material was apparently released from the conoid and a large membrane-bound vacuole was formed in the anterior end of the sporozoite, displacing the typical anterior electron-dense organelles (rhoptries and micronemes). The outer membrane of the sporozoite pellicle then fused with the host cell membrane immediately adjacent to the conoid. The membrane surrounding the anterior vacuole was also fused with the common host-parasite membrane, forming Y-shaped membrane junctions where each limb was a unit membrane. A direct link was thereby established between the anterior vacuole of the sporozoite and the host cell cytoplasm. The anterior vacuole membrane separating the sporozoite and the host cell cytoplasm was the precursor of the feeder organelle.
Animals↗
Colonization factor antigens and a new fimbrial type, CFA/V, on O115:H40 and H- strains of enterotoxigenic Escherichia coli in central Australia.
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Antigens, Bacterial↗
Variation in cuff blood pressure in untreated outpatients with mild hypertension--implications for initiating antihypertensive treatment.
Thirty-two patients with mildly elevated blood pressure (BP), but without target organ damage, attended a BP measuring clinic where duplicate BP measurements were made on 12 visits. During visits 1-3, BP showed a systematic decrease which varied from patient to patient. During visits 4-12, no further systematic changes in BP were observed. During the latter period, between-visit variation in BP was substantial, the standard deviation of the difference in BP from one visit to another being 10.4 mmHg for systolic, 6.8 mmHg for diastolic (phase IV) and 7.0 mmHg for diastolic (phase V). These values were used to determine the chance that the BP estimated after a number of visits differed from the average stable BP. After visit 4, the chance of a difference of 5 mmHg or more was 0.50 systolic blood pressure (SBP) and 0.32 diastolic blood pressure (DBP; phase V). Increasing the number of visits to six or more reduced the chance of error. Before initiating lifelong treatment in mild hypertensives free of target organ damage, BP should be recorded in duplicate on a minimum of six visits.
Adult↗
Electrophoretic and immunoblot analysis of Cryptosporidium oocysts.
Cryptosporidium oocysts were recovered by density gradient centrifugation from diarrhoeal faeces of four human patients and one goat kid. Goat-derived oocysts were further treated with excystation medium and the excysted oocyst walls purified by isopycnic ultracentrifugation. Soluble extracts from intact oocysts and the oocyst wall preparation were analysed by SDS-PAGE. Fifty-one polypeptide bands were detected in intact oocyst preparations: 48 were in the range 14,000-200,000 molecular weight (MW), two bands were less than 14,000 MW and one band was above 200,000 MW. Twenty-one bands were detected in the oocyst wall preparation, all within the range 14,000-200,000 MW. Immunoblot analysis of Cryptosporidium polypeptides using acute or convalescent human and goat sera revealed a large number of reactive bands. Varying degrees of heterogeneity were observed within and between the two serum groups. Nine of the 10 human sera and all of the goat kid sera reacted with a 23,000 MW and 32,000 MW antigen. A 15,500 MW antigen was also detected by all the goat and four of the 10 human sera. Both serum groups reacted with various antigens above 40,000 MW. Surface labelling of three human isolates of Cryptosporidium oocysts with 125I was performed using the Bolton and Hunter reagent. The solubilized preparations were separated by SDS-PAGE on 12% and 18% slab gels and autoradiographed. Common bands were seen at 15,500, 32,000, 47,500, 79,000 and 96,000 MW. Some variation in the molecular weight of polypeptides labelled with 125I was observed among the three isolates.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗