Histological changes over time around the site of sustained release naltrexone-poly(DL-lactide) implants in humans.

In order to assess the histological tissue changes over time around the site of implant, tissue biopsies were taken at 1 to 38 months post-implant from 54 (34 male) consenting human subjects who had received the Australian subcutaneous naltrexone-poly(DL-lactide) implant for heroin dependence. The implant consists of multiple tablets containing compressed naltrexone-poly[trans-3,6-dimethyl-1,4-dioxane-2,5-dione] (DL-lactide) loaded microspheres. Assessment of tissue samples by pathologists showed an early phase (up to 12 months post-implant) of inflammation, foreign body reaction, and fibrosis. This subsided gradually over the next 12 months until tissue returned to normal by 25+ months. Sufficient evidence was not available to conclude that the poly(DL-lactide) implant matrix was totally biodegradable within the study period. While implant material was not identified in most of the latter biopsies, its presence was noted in one biopsy at 26 months post-implant. Nevertheless the study results did demonstrate the implant's biocompatibility by the lack of inflammation, foreign body reaction, and fibrosis detected by 25+ months. It seems highly probable that surgical technique rather than the implant itself was associated with the additional finding of fat necrosis. Moderate fat necrosis was observed as a common feature of biopsies carried out during the first 6 months following implant. It subsided to mild levels over the next 18 months, and was notably absent by 25+ months. The results of the study indicated that the Australian naltrexone-poly(DL-lactide) implant is well tolerated and may have a role for use in the management of medical conditions such as heroin dependence.     

Transient shock and myocardial impairment caused by phaeochromocytoma crisis

A patient admitted to hospital after injury to the abdomen was found to have transient hypertension which was followed by profound hypotension. ST elevation developed and extensive myocardial akinesia was seen at echocardiography, but coronary angiograms at this stage were normal. After treatment with intravenous fluids and dopamine he progressively recovered normal cardiac function. A partly necrotic catecholamine secreting tumour was later removed from the abdomen and it is likely that a kick to the abdomen had damaged the tumour and the consequent release of catecholamine had triggered a phaeochromocytoma crisis.     

Late spontaneous recovery of chronic thrombocytopenia.

Five cases are reported of spontaneous remission of chronic childhood thrombocytopenia four or more years after diagnosis. Other than typical features of chronic idiopathic thrombocytopenic purpura there were no obvious markers predictive of late remission, although a slow progressive recovery was common to four of the patients. In light of this experience splenectomy is not recommended in clinically mild thrombocytopenia.     

Trimethoprim resistant dihydrofolate reductases in normal faecal flora isolated in India.

A high incidence of resistance to trimethoprim has been shown in the normal faecal flora in a population in south India. The dihydrofolate reductase (dhfr) genes mediating transferable resistance to trimethoprim have been identified. Unusually, in this study, the dhfrV was shown to be the predominant resistance gene (dhfrV 50% of transconjugants, dhfrIa 30%), the dhfrIb was also detected being distinguished from the dhfrV by an oligo-probe. However, when non-transferable resistance was considered, the dhfrIa was the most prevalent of the dhfrs identified. All those plasmids harbouring the dhfrIa were shown to possess Tn7. All the plasmids that probed positive for the dhfrV and the dhfrIb were shown to be associated with the integrase of the Tn21-like transposons, but 8 of the dhfrV genes were not associated with the Tn21 resolvase. The dhfrIV was shown to be present in all seven plasmids that produced low level trimethoprim-resistance. The dhfrV, first characterized in Sri Lanka, would seem to have a local distribution in this region of Asia but is distinguishable from the dhfrIb only by the use of an oligo-probe.