258 research outputs found
Cryptococcal meningitis
Cryptococcal meningitis occurred in an elderly Coloured woman in the Northern Cape. She presented with symptoms and signs suggestive of encephalitis 4 weeks after a cholecystectomy. After the administration of cortisone, cryptococcal organisms were isolated in her cerebrospinal fluid. She was first treated with intravenous amphotericin-B without improvement, and then with 5-f1uorocytosine orally, to which she responded without appreciable sideeffects. An abdominal gland biopsy suggested sarcoidosis, but sarcoid reaction may occur in the presence of cryptococcosis,Ā although the organisms could not be demonstrated, as is often the case.S. Afr. Med. J., 48, 555 (1974)
Cryptococcal Meningitis
Cryptococcal meningitis occurred in an elderly Coloured woman in the Northern Cape. She presented with symptomsĀ and signs suggestive of encephalitis 4 weeks after a cholecystectomy. After the administration of cortisone,Ā cryptococcal organisms were isolated in her cerebrospinal fluid. She was first treated with intravenous amphotericin-B without improvement, and then with 5-f1uorocytosineĀ orally, to which she responded without appreciable sideeffects. An abdominal gland biopsy suggested sarcoidosis, but sarcoid reaction may occur in the presence of cryptococcosis,Ā although the organisms could not be demonstrated,Ā as is often the case.S. Afr. Med. J., 48, 555 (1974)
Oestrogen receptor mutations and their influence on breast cancer growth
Ph.D., Faculty of Health Sciences, University of the Witwatersrand, 2011Oestrogen receptor (ER) mutations have been identified for both ERĪ± and ERĪ² in
previous studies. The effects of the deletion variants due to splice mutations on
clinical parameters, prognosis and treatment were examined in 61 breast
carcinoma patients and 13 control samples from elective reduction mammoplasty
procedures, respectively. RNA extracted from fine needle aspirates (FNAs) of
breast tissue was reverse transcribed and using nested PCR and sequence
analysis the presence of these variants elucidated. Using Ī§2 and Fisherās exact
tests their significance with respect to clinical parameters such as tumour size,
nodal involvement, stage, presence or absence of metastases, menstrual status
and hormone responsiveness was examined. Kaplan-Meier survival analysis was
also determined.
The T-47D breast cancer cell line was cloned with two clones being selected for
further analysis, namely TCA3 (hormone sensitive) and TCC1 (hormone resistant).
These clones were treated for ten passages with oestrogen metabolites, 17-Ī²-
oestradiol and oestriol; oestrogen precursors, androstenedione and cholesterol; an
anti-oestrogen, 4-hydroxy-tamoxifen; and the aromatase inhibitor
aminoglutethimide, respectively. RNA was extracted from the cells initially and
after the tenth passage and the ERĪ± and ERĪ² exon profiles were examined using
RT-PCR and sequence analysis. After the tenth passage hormone response tests
were performed every 24 hours (up to 96 hours) with cell number being
determined using the MTT assay.
The results indicate that ERĪ± and ERĪ² variants do not have any affect with respect
to menstrual status and nodal involvement (N). Expression of ERĪ±2 and ERĪ±4 are
required by the mouse monoclonal antibody (DAKO Ā® Clone 1D5) in the
immunocytochemical assay used for the recognition of the protein in order to
assess ER status and therefore show significance. ERĪ±Ī2 and, contrary to
previous investigations, the variant ERĪ±Ī3 were not found to play a role in
tumourigenesis. ERĪ±Ī5 was observed to be more prevalent in ERĪ±-positive
patients and was usually co-expressed with the complete ERĪ±5 indicating
heterodimerization. ERĪ±Ī5 showed no significance with respect to progression of
disease or response to hormone treatment.
An increase in the ratio of ERĪ±Ī4: wild-type ERĪ±4 indicated an increase in
metastatic potential of diseased tissue. ERĪ±4 and ERĪ±Ī4 heterodimers were
present in both T-47D clones and after 10 passages the TCA3 clone grown in
10-8M aminoglutethimide indicated a complete loss of ERĪ±4 without altering
hormone responsiveness. These results suggest that ERĪ±Ī4 may play a role in
progression of disease but not in the acquisition of tamoxifen resistance.
ERĪ±Ī6 was observed in 15% of patients but not in the T-47D clones or the control
samples. An increase in the expression of ERĪ±Ī6 among patient samples
significantly increased their metastatic potential (p=0.018). ERĪ±Ī6 was also
observed as significant with respect to stage of disease (p=0.023) indicating the
possible relevance of ERĪ±Ī6 in progression of the disease.
ERĪ±Ī7 was the most frequently observed variant and did not show any
significance with regard to any of the clinical parameters examined. The presence
of ERĪ±Ī7 did not show significance with regard to hormone response in vivo but in
vitro the presence of this variant, expressed as a heterodimer with the wild-type
ERĪ±7, conferred greater sensitivity to tamoxifen in the tamoxifen resistant clone
TCC1.
Multiple exon deletions of ERĪ± were also observed. The two more significant
multiple deletion variants were those involving ERĪ±Ī4, namely, ERĪ±Ī2-ERĪ±Ī6
and ERĪ±Ī4-ERĪ±Ī6. The multiple variant ERĪ±Ī4-ERĪ±Ī6 may be involved in
tumour progression.
ERĪ² variants were not examined in as much detail as ERĪ± variants due to
insufficient material available for analysis. The two domains, the DNA binding
domain and the ligand binding domain, of ERĪ² were analyzed in a few of the
patients and in the T-47D clones. They were not found to be significant with
respect to the clinical parameters investigated and the ERĪ² profiles of the TCA3
and TCC1 clones remained unchanged after 10 passages under varying growth conditions
Centromeric Repositioning of Coreceptor Loci Predicts Their Stable Silencing and the CD4/CD8 Lineage Choice
The differentiation of CD4+ CD8+ double positive (DP) thymocytes requires the irreversible choice between two alternative lineages, distinguished by the mutually exclusive expression of either CD4 or CD8. Differentiating DP cells transiently down-regulate both CD4 and CD8, and this has complicated the debate whether the mechanism of CD4/CD8 lineage choice is instructive, stochastic/selective, or more complex in nature. Using fluorescence in situ hybridization, we show that the stable silencing of coreceptor loci, and ultimately lineage choice, is predicted by the spatial repositioning of coreceptor alleles to centromeric heterochromatin domains. These data provide evidence that lineage-specific developmental programs are established early during the transition from the DP to the single positive stage
The impact of chromatin modifiers on the timing of locus replication in mouse embryonic stem cells
A panel of mutant embryonic stem (ES) cell lines lacking important chromatin modifiers was used to dissect the relationship between chromatin structure and replication timing, revealing the importance of several chromatin modifiers for maintaining correct replication of satellite sequences in pluripotent ES cells
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