Simplifying collection of corneal specimens in cases of suspected bacterial keratitis

Identification of the causative organisms in suspected bacterial keratitis traditionally involves collecting multiple corneal scrapes, which are plated directly onto different solid agar culture media. Difficulties have been reported with this practice, so the development of a simpler diagnostic method in suspected bacterial keratitis would be useful. It is unclear whether a single corneal scrape sent to the microbiology laboratory in a liquid transport culture medium (indirect method) is as reliable for the diagnosis of bacterial keratitis as inoculation of multiple scrapes directly onto agar plates (direct method). To investigate this, bacterial recovery was assessed following transfer and transport of different concentrations and types of bacteria from an artificially contaminated surgical blade into brain heart infusion (BHI). Bacterial recovery rates between the proposed (indirect) and standard (direct) method were then compared after the in vitro inoculation of pig corneas and following specimen collection in patients with presumed bacterial ulcerative keratitis. Recovery of bacteria from contaminated surgical blades was found to be the same from both solid and liquid culture media. There was no significant difference in the numbers of positive cultures from solid (direct) and liquid (indirect) culture media, both in the experimental pig cornea inoculation study (P = 0.34) and in experiments with patients with clinical infections (P = 0.4), with an 85.2% agreement between methods (kappa = 0.61, P < 0.0001). In conclusion, therefore, the collection of two corneal scrapes, one used for Gram staining and the other transported in BHI followed by plating and subculturing in an enrichment medium, provides a simple method for the investigation of presumed bacterial keratitis.     

Intraoral melanoma: long-term follow-up and implication for dental clinicians. A case report and literature review

Primary intraoral melanoma is a rare neoplasm with a poor prognosis, accounting for 1% to 8% of all melanoma in Europe and the United States. The incidence (12%) and 5-year survival rate (17.4%) are higher in Japan. We report a case of oral lentiginous melanoma in a Japanese-American man who survived disease-free for more than 5 years after surgery, radiation therapy, and chemotherapy but developed chronic mucositis of the palate under the denture in the primary radiated field. This lesion responded to antifungal therapy. Subsequent multiple biopsies ruled out the recurrence of melanoma but demonstrated prolonged melanocytic hyperplasia and focal epithelial atypia. We reviewed clinical differences in oral melanoma reported in the United States and Japanese literature, and describe the wide variety of oral clinical features of postoperative radiation and chemotherapy, as well as the oral tissue changes caused by denture-induced mucositis and candidiasis in such patients. Dental clinicians should conduct a thorough head, neck, and oral follow-up with increased vigilance in patients with a history of prior cancer.     

An unusual family with multiple movement disorders

Multiple movement disorders presenting in the same family are rare. We present an unusual family where generalized dystonia, Huntington's disease, progressive supranuclear palsy and secondary paroxysmal dyskinesia co-exist. The index case presented with young-onset dystonia and tested negative for the DYT1 gene deletion. Her father was similarly affected. The father's brother (paternal uncle of the index) also had abnormal movements-a mixture of chorea and dystonia-and tested positive for the HD expansion. His son had secondary paroxysmal dyskinesia, and tested negative for the HD expansion. The index case and her father were also negative for the HD expansion. A paternal aunt of two of the cases had a clinical diagnosis of progressive supranuclear palsy.Dystonia is known to be a genetically heterogeneous condition. The co-existence of inherited generalized dystonia with other movement disorders may provide clues to its genetic localization.     

Microglia density decreases with age in a mouse model of Huntington's disease

Huntington's disease (HD) is characterized by selective neuronal loss and reactive gliosis. In the R6/2 transgenic HD mouse model, there is no selective cell loss, although astrocytosis has been reported. Since there have been no previous studies on microglia in this model, we have undertaken a detailed investigation of microglia in six different forebrain regions in the R6/2 mouse and their wild-type littermates at two time points. Microglia were identified using the histochemical marker isolectin B4 and interactions of genotype, region, and age were analyzed. Results showed that there was a significant decrease in the number of microglia with age in both wild-type and R6/2 brains, which was more pronounced in the transgenic mouse. There were also morphological changes with age observed in both genotypes. As early as 7 weeks of age, structural microglial abnormalities could be seen in R6/2 brains, including bulbous swellings and long stringy processes; comparable changes were seen at 16 weeks in wild-type brains. At 14.5 weeks, microglia in R6/2 mouse brains were smaller in size with condensed nuclei and fragmentation of their processes. We suggest that the density and morphology of microglia change with normal aging and that this process is accelerated in R6/2 brains. Such changes in the dynamic status of microglia may lead to an impairment of their neurosupportive functions. Further studies are needed to understand better the role of microglia in aging and neurodegeneration.     

A novel mitochondrial tRNA(Leu(UUR)) mutation in a patient with features of MERRF and Kearns-Sayre syndrome

In a patient with clinical features of both myoclonus epilepsy ragged-red fibers (MERRF) and Kearns-Sayre syndrome (KSS), we identified a novel guanine-to-adenine mitochondrial DNA (mtDNA) mutation at nucleotide 3255 (G3255A) of the tRNA(Leu(UUR)) gene. Approximately 5% of the skeletal muscle fibers had excessive mitochondria by succinate dehydrogenase histochemistry while a smaller proportion showed cytochrome c oxidase (COX) deficiency. In skeletal muscle, activities of mitochondrial respiratory chain complexes I, I + III, II + III, and IV were reduced. The G3255A transition was heteroplasmic in all tissues tested: muscle (53%), urine sediment (67%), peripheral leukocytes (22%), and cultured skin fibroblasts (< 2%). The mutation was absent in 50 control DNA samples. Single-fiber analysis revealed a higher proportion of mutation in COX-deficient RRF (94% +/- 5, n = 25) compared to COX-positive non-RRF (18% +/- 9, n = 21). The identification of yet another tRNA(Leu(UUR)) mutation reinforces the concept that this gene is a hot-spot for pathogenic mtDNA mutations.     

Quantitative assessment of the radiation hazards and risks in sentinel node procedures

Sentinel node localization using an injected radiopharmaceutical and a gamma probe is performed in many hospitals. Employers have a duty to give appropriate training to staff who may not have been previously formally trained to work with unsealed radioactive sources. A study was performed to assess hazards and risks at all stages of the localization procedure. Whole body doses and finger doses of imaging, surgery and pathology staff were determined. The activity remaining in the tumour specimen, excised nodes and disposable waste from the operating theatre was measured. Any radioactive contamination of the operating theatre and equipment was also ascertained. All results were then assessed in light of current UK radiation protection legislation for the protection of staff and members of the public. Results showed that radiation doses are low and no additional procedures are required for protection of staff, provided the usual procedures for biohazards are in place. However, an information sheet has been prepared for the reassurance of staff, and theatre swabs may need to be stored temporarily before disposal. Injecting and imaging on the day before surgery is preferred, compared with injecting and imaging before surgery on the same day, since this gives lower radiation doses to staff, lower activity in excised specimens and waste, and provides a higher count rate giving better image quality.