Visual impairment in severe and profound sensorineural deafness

The frequency of reversible and irreversible visual impairment was determined in children with severe and profound sensorineural deafness, as subnormal vision can adversely affect their educational and social development. Eighty three of 87 such children attending an audiology service were examined to assess the incidence and severity of visual impairment. Each child underwent a detailed ophthalmic assessment. The criteria for visual impairment were visual acuity < 6/9 Snellen or equivalent and/or abnormal binocular vision. Forty five had a normal ophthalmic examination (54.2%). Twenty nine had visual impairment (34.9%) and nine had ophthalmological abnormalities that did not interfere with vision (10.9%). A higher proportion of children with risk factors for visual pathology demonstrated visual impairment than those in whom there were no risk factors. None the less, 44% of visual impairment was among patients without risk factors. The results underline the need to examine all children with severe and profound sensorineural deafness soon after diagnosis and indicate that children with multiple handicaps have a greater likelihood of visual impairment (11 of 14 cases).     

Stages in reproduction particularly vulnerable to xenobiotic hazards and nutritional deficits

Biochemical research has identified many failures in reproductive processes with specific nutrient deficits, xenobiotics and some infectious illnesses. This has led to some effective safeguards. During meiosis and fertilization, as genetic material divides and rearranges, it is exposed and open to mutation. A nutritionally unfavourable environment is a major risk factor. At stages of rapid cell division, differentiation and organisation, as in the embryo and later in the fetal brain, the child's survival, completeness and future health and ability are at stake. From months before conception, reproduction needs preparing for, especially with today's environmental pollution, even entering the foodchain. Care from before conception can contribute not only to the child's healthy basis for life, full development of brain, eyesight and other complex attributes, but also to the health of at least the subsequent generation. Since the female baby's oocytes are being formed while she is still in the womb, the grandmother's nutritional status, around the time of conceiving a daughter, can permanently affect a grandchild. Recent insights into evolution, particularly of the brain, give us fresh indications of dietary needs to fulfil human potential for health and acuity. Despite the hazards, nature is remarkably successful. This paper is not designed to alarm but to help attainment of full genetic potential. With healthy parents serious malformations are a low percentage. The numbers of babies with avoidable disorders, however, calls urgently for action, especially in our own inner cities and in developing countries where there is inadequate nutrition. Action will more than justify itself, including financially. It will reward handsomely.     

Changing concepts of acoustic neuroma diagnosis

Three hundred five acoustic neuromas were reviewed to determine the sensitivity of combining the auditory brainstem response (ABR) and the intravenous contrast-enhanced computed tomogram (CT) as screening tests for acoustic neuroma diagnosis. The ABR detected 98% of the tumors. The enhanced CT demonstrated 97% of tumors larger than 1.5 cm, but only 48% of neuromas 1.5 cm or smaller. The combination of both ABR and enhanced CT, used as the initial screening tests, identified 99% of the neuromas. We conclude that ABR, with enhanced CT as needed, is an accurate screening protocol. This method can be used as an alternative to the traditional ABR, electronystagmography, and internal auditory canal tomograms.     

Methods and limits of digital image compression of retinal images for telemedicine

PURPOSE: To investigate image compression of digital retinal images and the effect of various levels of compression on the quality of the images. METHODS: JPEG (Joint Photographic Experts Group) and Wavelet image compression techniques were applied in five different levels to 11 eyes with subtle retinal abnormalities and to 4 normal eyes. Image quality was assessed by four different methods: calculation of the root mean square (RMS) error between the original and compressed image, determining the level of arteriole branching, identification of retinal abnormalities by experienced observers, and a subjective assessment of overall image quality. To verify the techniques used and findings, a second set of retinal images was assessed by calculation of RMS error and overall image quality. RESULTS: Plots and tabulations of the data as a function of the final image size showed that when the original image size of 1.5 MB was reduced to 29 KB using JPEG compression, there was no serious degradation in quality. The smallest Wavelet compressed images in this study (15 KB) were generally still of acceptable quality. CONCLUSIONS: For situations where digital image transmission time and costs should be minimized, Wavelet image compression to 15 KB is recommended, although there is a slight cost of computational time. Where computational time should be minimized, and to remain compatible with other imaging systems, the use of JPEG compression to 29 KB is an excellent alternative.     

A comparison of the effects of maternally administered meptazinol and pethidine on neonatal acid-base status

Summary. A randomized double-blind study compared the effects of equi-analgesic doses of maternally administered meptazinol (1.5 mg/kg) and pethidine (1.5 mg/kg) on neonatal acid-base status. Heel-prick samples were taken for assessment of acid-base status at 10 and 60 min after delivery. Maternal antenatal history, details of labour and neonatal status at delivery were also recorded. Meptazinol produced less neonatal respiratory depression than pethidine: the mean 10 min acid-base data from 16 infants whose mothers received pethidine were indicative of a respiratory acidosis (pH 7.13, SD 0.08, P co₂,9.11, SD 2.2 kPa; standard bicarbonate 22.3, SD 3.1 mmol/1). This was not evident in the mean acid-base data from 16 infants whose mothers received meptazinol (pH 7.23, SD 0.07; P co₂ 6.83, SD 1.6 kPa; standard bicarbonate 20.9, SD 4.2 mmol/1). The mean pH and P co₂ in the two treatment groups were significantly different (P<0.002) at 10 min but not at 60 min after delivery.     

Moderate renal insufficiency and the risk of cardiovascular mortality: results from the NHANES I

BACKGROUND: Conflicting evidence exists concerning whether renal insufficiency is an independent risk factor for cardiovascular disease in the general population. The objective of this study was to determine whether moderate renal insufficiency was associated with total and cardiovascular mortality, independent of traditional cardiovascular risk factors, in a community sample representative of the U.S. general non-institutionalized population. METHODS: Participants in the U.S. First National Health and Nutrition Examination Survey (NHANES I, 1974-1975) and NHANES I Epidemiologic Follow-up Study (NHEFS, 1992, 18 year follow-up) were evaluated. The primary analysis was limited to 2352 adults with complete data, and no baseline cardiovascular disease. A creatinine of 104 to 146 micromol/L in women, and 122 to 177 micromol/L in men (approximate glomerular filtration rate of 30 to 60 mL/min/1.73 m2) was defined as moderate renal insufficiency. Supplementary analyses included participants with marked renal impairment and baseline cardiovascular disease. RESULTS: The unadjusted hazard ratio for moderate renal insufficiency compared to preserved renal function was significant for total mortality (hazard ratio 1.7; 95% confidence interval 1.3 to 2.2), and for cardiovascular mortality (2.2; 1.5 to 3.1). After adjustment for traditional cardiovascular risk factors, there was no independent association between moderate renal insufficiency and total mortality (1.0; 0.8 to 1.4), or cardiovascular mortality (1.2; 0.8 to 1.8). These results were consistent in supplementary analyses. CONCLUSIONS: These results do not support moderate renal insufficiency as an independent risk factor for cardiovascular disease in the general population. The association between moderate renal insufficiency and cardiovascular disease, demonstrated in other epidemiologic studies, appears to be due to co-occurrence of renal insufficiency with traditional cardiovascular risk factors.     

Vasopressin gene expression: experimental models and strategies

The intergenic region (IGR) separating the genes for vasopressin (VP) and oxytocin (OT) has been shown to be critical for the cell-specific expression of these peptide genes in hypothalamic neurons. To date, the most relevant information about the putative cis-elements in the IGR that might determine cell-specific gene expression has come from studies in transgenic models. As a first step toward increasing the efficiency of the IGR sequence deletion studies in transgenic animals, a comparative genomics approach comparing the IGR sequence in humans versus mice was used to identify conserved sequences that might be candidate regulatory elements. The nucleotide sequence of the IGR between the human VP and OT genes was determined and compared to the mouse IGR, and 26 conserved sequences in three distinct clusters were found. These conserved sequences and motifs may be important for the cell-specific expression of the VP and OT genes. However, before further significant progress can be made, a "high-throughput" method for the analysis of deletion constructs in relevant cell types in vitro is needed. It is proposed here that organotypic culture models combined with the use of particle-mediated gene transfer methods may provide an effective, general strategy for the study of cell-specific expression in the central nervous system.