K-W Leung | PubMed Health

PubMed2006

Aging and mfERG topography.

AIM: To study the effect of aging retina on the multifocal electroretinogram (mfERG). METHODS: A total of 18 young subjects (age 18-24 years) and 36 elderly subjects (aged 60-85 years) with intraocular lenses (IOLs) were recruited for this study. No subjects had significant eye diseases or media opacities. mfERG was measured in standard conditions using the VERIS system (version 4.1). There were three groups of 18 subjects: (1) 18-25 years, (2) 60-70 years, and (3) 75-85 years. mfERG responses were grouped into central, paracentral, and peripheral regions for analysis. The N1 amplitude, P1 amplitude, N1 latency, and P1 latency of the first-order responses were analysed. RESULTS: Age had no effect on P1 latency, N1 amplitude, and P1 amplitude; however, N1 latencies from central to peripheral regions were significantly longer for group 3 than for group 1. CONCLUSIONS: This study suggests that measured age-related decreases in mfERG responses are due to optical factors (decrease in retinal light levels, scatter) before the age of 70 years, but neural factors significantly affect mfERG topography after the age of 70 years.

Adult↗

PubMed2006

Globicatella bacteraemia identified by 16S ribosomal RNA gene sequencing.

BACKGROUND: Globicatella are streptococcus-like organisms that have been rarely isolated from clinical specimens. Their epidemiology and clinical significance remain largely unknown. AIMS: To describe two cases of Globicatella bacteraemia identified by 16S ribosomal RNA (rRNA) gene sequencing. METHODS: Two unidentified streptococcus-like bacteria isolated from blood cultures of patients were subject to 16S rRNA gene sequencing. RESULTS: Two cases of Globicatella bacteraemia were identified by 16S rRNA gene sequencing. In the first case, a gram positive coccus was isolated from the blood culture of an 80 year old woman with diabetes mellitus and nosocomial sepsis, who died the day after developing the bacteraemia. The bacterium was unidentified by conventional phenotypic tests, the Vitek (gram positive identification) and the ATB expression (ID32 Strep) systems. In the second case, a similar bacterium was isolated from the blood culture of a 92 year old woman with polymicrobial acute pyelonephritis complicated by septic shock, who subsequently recovered after antibiotic treatment. 16S rRNA gene sequencing of the two isolates showed 0.5% nucleotide difference from that of G. sulfidifaciens and 0.7% nucleotide difference from that of G. sanguinis, indicating that they were Globicatella species. CONCLUSIONS: Because Globicatella is rarely encountered in clinical microbiology laboratories, it may have been overlooked or misidentified in these cases. 16S rRNA gene sequencing is a useful tool to better characterise the epidemiology and clinical significance of Globicatella.

Aged, 80 and over↗