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Biomedical subjects

I Bastian

Publications and source records attributed to I Bastian.

34 records · Page 2Linked to original sources

New World cutaneous leishmaniasis imported into Australia.

A case of cutaneous leishmaniasis in a traveller from Belize, Central America is reported. Leishmaniasis presents rarely in Australia and delays in diagnosis and treatment often occur. A high index of suspicion in a patient who has returned from an endemic region is required. Subsequent confirmation of a diagnosis of cutaneous leishmaniasis is best achieved by demonstration of the organism on skin biopsy, aspiration or smear. The histology is variable and depends on geographic, parasite species and host factors. Speciation of New World disease as either Leishmania braziliensis or Leishmania mexicana is important to determine the risk of later development of mucosal disease, which normally only occurs with L. braziliensis infection, and for optimal treatment. Several different modes of treatment have been suggested, but antimonials, such as sodium stibogluconate, remain the treatment of choice in New World cutaneous leishmaniasis.

Adult↗

A community-based approach to the control of sexually transmitted diseases in the Northern Territory.

A program to control sexually transmitted diseases (STDs) was undertaken during a Men's Health Week in a remote Aboriginal community in Western Arnhem Land, Northern Territory. A total of 151 men aged 13 years and over who attended over a five-day period underwent a full physical examination, and first-void urine specimens were tested for the presence of leukocytes, chlamydia (by enzyme immunoassay antigen detection) and gonorrhoea (by culture and antigen detection). Blood was taken for syphilis serology from all patients and for human immunodeficiency virus (HIV) from patients with a proven STD or at the patient's request. Consent for testing was obtained from all participants. Patients with a positive urinary leukocyte test or symptoms were offered urethral swab investigations and treated empirically according to a set protocol. Patients with STDs detected by subsequent laboratory investigations were followed up and treated. The overall prevalence of one or more of syphilis, gonorrhoea or chlamydia was 17.4 per cent. No men presented with genitourinary symptoms and none was HIV-infected. In this population, STDs were an important cause of morbidity, and a community-based approach was adopted to identify infected persons. The use of urine for the detection of gonorrhoea and chlamydia was highly acceptable. Although not used in this study, polymerase chain reaction and ligase chain reaction technology will facilitate similar activities in the future.

Adolescent↗

Phenotypic and molecular characterization of three clinical isolates of Mycobacterium interjectum.

Introduction of molecular biology-based technology into an Australian mycobacterial reference laboratory has resulted in the identification of three isolates of Mycobacterium interjectum in the past 12 months. Conventional phenotypic methods failed to identify the species of these isolates, and high-performance liquid chromatography found that only one of the three isolates had a mycolic acid pattern similar to that of the type strain. In contrast, all three isolates were rapidly identified as M. interjectum by 16S rRNA gene sequence analysis. Two isolates were recovered from the lymph nodes of children with cervical lymphadenitis, confirming the pathogenicity of this organism. However, the third isolate was obtained from the sputum of an elderly male with chronic lung disease without evidence of clinical or radiological progression, suggesting that isolation of M. interjectum should not imply disease. With the increasing use of molecular biology-based technology in mycobacterial laboratories, M. interjectum may be recognized more frequently as a pathogen or commensal organism.

Aged↗

Pilot study of azithromycin in the treatment of genital donovanosis.

OBJECTIVES: To determine the effectiveness of azithromycin, an azalide antibiotic with long tissue half-life, in a pilot study of patients with genital donovanosis in the Northern Territory, Australia. DESIGN: Patients with histologically confirmed donovanosis were randomised to receive one of two open-label azithromycin dosage regimens: Regimen A--1.0 g once weekly for 4 weeks; or Regimen B--500 mg daily for 7 days. Patients were assessed at 6 weeks and classified as either "cured", "improved" or "failed". RESULTS: Seven patients received regimen A and 4 received regimen B. Six weeks after commencing treatment the genital ulcers of four patients receiving regimen A and one patient receiving regimen B had healed; the lesions of the other six patients (3 in each regimen) were "improved". No patient failed to respond and no significant adverse reaction was recognised. The eleven patients were reviewed after completing the six-week trial; all lesions had re-epithelialised without further antibiotic treatment, no relapses had occurred, the longest follow-up period being seven months. A further 17 patients with donovanosis who were unable to meet the entry criteria were also treated successfully with azithromycin during the study period. CONCLUSIONS: This is the first time that azithromycin has been shown to have clinical activity against donovanosis. Poor compliance with prolonged courses of antibiotics is one of the major barriers to control of the disease. Intermittent or short-course therapy, made possible by the long tissue half-life of the drug, could facilitate control of donovanosis in endemic populations if the high cost of medication can be addressed.

Adolescent↗

Molecular phylogeny and dissemination of human T-cell lymphotropic virus type I viewed within the context of primate evolution and human migration.

A renewed interest in the emergence and evolution of the primate T-cell lymphotropic viruses has followed the discovery of genetically distinct variants of human T-cell lymphotropic virus type I (HTLV-I) in Melanesia and Australia. Phylogenetic trees based on selected regions of the gag, pol, env and pX genes of HTLV-I from widely separated geographic regions and of simian T-cell lymphotropic virus type I (STLV-I) from African and Asian catarrhines, constructed using the neighbor-joining and maximum parsimony methods, indicated that the Australo-Melanesian and cosmopolitan strains of HTLV-I have evolved along separate geographically dependent lineages, with African STLV-I strains clustering with cosmopolitan HTLV-I strains and Asian STLV-I strains diverging from the common ancestral virus before the Australo-Melanesian HTLV-I strains. When viewed within the context of non-human primate evolution and human occupation of Australia and Melanesia, the rate of molecular change of HTLV-I and STLV-I is approximately 2.5-6.8 x 10(-7) substitutions per site per year. Overall, the sequence and phylogenetic analyses are in accord with interspecies virus transmission among non-human primates, as well as between non-human primates and humans, with independent evolution of HTLV-I in Southeast Asia and in Africa, and with dissemination of HTLV-I by forced or voluntary movements of human populations. The immunosuppressive and T-cell activation properties of HTLV-I places at added risk these Australian Aboriginal and Melanesian populations, some of which are in imminent threat of infection with human immunodeficiency virus type 1.

Africa↗

HTLV-I among Northern Territory blood donors.

OBJECTIVE: Human T-lymphotropic virus type I (HTLV-I) is known to be endemic among Northern Territory (NT) Aborigines, therefore evidence was sought of HTLV-I infection in NT blood donors. DESIGN: Samples were screened for HTLV-I antibodies using the Serodia HTLV-I particle-agglutination assay. Repeatedly reactive sera were tested by western blot. Viro- logical and molecular investigations were also performed. SERA: Aliquots from all 11,121 blood donations collected between June 1991 and August 1992. RESULTS: Four (0.036% of total) blood donations, each from different donors, were repeatedly reactive by particle-agglutination assay. One (0.009%) sample, from a 52-year-old non-Aboriginal man with no verified risk factors, was confirmed as HTLV-I seropositive by western blot. A viral isolate and a 431 base pair polymerase chain reaction product from the env gene were obtained from a culture of his peripheral blood mononuclear cells. Sequencing of the polymerase chain reaction product demonstrates that this isolate is a prototype strain and not the variant identified among Aborigines. The remaining three repeatedly reactive donors, including the positive donor's wife, were western blot indeterminate. CONCLUSIONS: There is a low prevalence of HTLV-I carriage among blood donors in the NT, and presumably in other States. However, most repeatedly reactive donations prove to be western blot indeterminate, therefore additional tests are required to detect or exclude HTLV-I infection. Although universal screening of donations would virtually eliminate HTLV-I transmission by transfusion, it has disadvantages, including financial cost.

Adult↗

HTLV-I among Northern Territory aborigines.

OBJECTIVE: To survey the Aboriginal community of the Northern Territory for antibodies to human T-lymphotropic virus type I (HTLV-I) and to describe the distribution of the virus. DESIGN: A sero-epidemiological study using the Serodia particle-agglutination assay, indirect immunofluorescence and western blot. Evidence of HTLV-I-related diseases was sought through clinicians, and by searching the cancer register and medical records. SERA: Samples from 1897 Aborigines, including 1569 sera received by the Royal Darwin Hospital Pathology Department for syphilis serology between March and July 1988. Most of the specimens were from public health surveys and antenatal screening. RESULTS: Ninety-four samples (5.0%) were positive by the particle-agglutination assay method but only 36 (1.9%) were positive by both particle-agglutination assay and indirect immunofluorescence. After confirmation by western blot, the seroprevalence of HTLV-I was 1.7% (95% confidence interval, 1.2-2.3%). Western blot positivity was higher in samples from the "Cattle Country" and Alice Springs regions (i.e., 4.7% and 13.9% respectively). CONCLUSION: HTLV-I is endemic among Aborigines in inland Australia. These serological findings are supported by the recognition of two cases of adult T-cell leukaemia/lymphoma in this population.

Age Factors↗

HTLV-I associated myelopathy in a Seychellois immigrant.

OBJECTIVE: To describe the clinical and laboratory features of human T-lymphotropic virus type I (HTLV-I) associated myelopathy in an immigrant from the Seychelles. CLINICAL FEATURES: A slowly progressive myelopathy has been recently diagnosed in a 64-year-old woman who emigrated to Australia from the Seychelles in 1957. Sphincter disturbance and back pain were the first manifestations, followed by gait disturbance. Neurophysiological investigation supported the clinical diagnosis of a myelopathy and radiological investigations revealed no structural cause. Serum antibodies to HTLV-I were detected by enzyme-linked particle agglutination and the presence of antibodies to individual HTLV-I gene products in the serum was confirmed by western blot. The virus was detected in a culture of the patient's peripheral blood mononuclear cells by antigen capture assay and by sequencing a polymerase chain reaction product amplified from the env gene. INTERVENTION AND OUTCOME: The patient was advised of the nature and prognosis of her illness. Oral corticosteroids were tried without benefit. CONCLUSIONS: The prevalence of HTLV-I infection is low in Australia although it may be endemic in some Aboriginal communities. Most infections are asymptomatic but the chronic neurological disease associated with HTLV-I infection has now been shown to exist in this country. HTLV-I infection should be considered in the aetiology of myelopathy without another obvious cause.

Australia↗

Systemic lupus erythematosus in Australian aborigines: high prevalence, morbidity and mortality.

BACKGROUND: Racial differences occur in the incidence of systemic lupus erythematosus (SLE). It has been suggested that SLE occurs at a higher prevalence and with greater severity in Aboriginal Australians, but because of the small, widely distributed population base, this has not been well documented. AIMS: To confirm and document the clinical impression of an increased prevalence and severity of systemic lupus erythematosus (SLE) in Aboriginal Australians, and to identify prognostic indicators. METHODS: Top End Northern Territory (NT) Aborigines with SLE on 1 January 1984 or diagnosed thereafter were followed until 1 January 1991. Epidemiological, clinical and serological data were collected. RESULTS: Prevalence on 1 January 1991 estimated at 1:1900, at least twice the estimated prevalence in non-Aboriginal Australians. High frequencies of renal disease (62% with proteinuria > 0.5 g/day) and autoantibodies to the Sm antigen (29%) were identified, contributing to the high mortality. Five year survival rate was 60%, with 67% of deaths resulting from infection. CONCLUSIONS: There is a high prevalence of SLE in NT Aborigines. In view of probable under-recognition of mild cases the true prevalence is likely to be even higher. Although morbidity and mortality may have been overestimated for the same reason, both were found to be high. Improved living conditions and health care delivery may improve prognosis.

Adolescent↗

Isolation of a human T-lymphotropic virus type I strain from Australian aboriginals.

A human T-lymphotropic virus type I (HTLV-I) strain was isolated in a CD4+ T-lymphocyte culture established from a healthy seropositive Australian Aboriginal. This isolate, identified as HTLV-IMSHR-1, was detected by immunofluorescence with monoclonal antibodies, by the presence of gag-encoded protein p24 in the culture supernatant, and by cocultivation leading to infection and transformation of lymphocytes from an HTLV-I-negative donor. By using the polymerase chain reaction technique, the env gene and segments of the pol and pX regions of the proviral genome of HTLV-I(MSHR-1) were amplified and sequenced. Comparison with the envelope sequences of prototype strains revealed up to 7% divergence at the nucleotide level and 3.1 to 4.3% divergence in the predicted amino acid sequence. Phylogenetic analysis showed that the Australian and Melanesian isolates are related. Differential reactivity with monoclonal antibodies suggests that gag protein p19 of HTLV-I(MSHR-1) is also divergent. The potential for antigenic divergence between the prototype HTLV-I isolates and the Austro-Melanesian variants requires further investigation, because it would have implications for serodiagnosis and vaccine development.

Amino Acid Sequence↗

Adult T-cell leukaemia lymphoma in an aborigine.

A 44-year-old Aborigine with Adult T-cell Leukaemia/Lymphoma (ATLL) due to HTLV-I is reported. He presented with transverse myelitis of subacute onset, and subsequently developed frank T-cell leukaemia complicated by splenomegaly and hypercalcaemia. Cell surface marker studies showed a phenotype of CD3+ CD4+ CD8- CD25+, and serological and molecular studies confirmed HTLV-I infection. This is the first report of ATLL in an Australian Aborigine.

Adult↗