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PubMed2002

Characterization of myocardium, isolated cardiomyocytes, and blood pressure in WKHA and WKY rats.

We previously reported that the left ventricular (LV) mass of Wistar-Kyoto (WKY)-derived hyperactive (WKHA) rats was higher than that of WKY rats in the absence of a difference in systolic blood pressure. To extend these earlier observations, we conducted a series of functional and morphological investigations on both strains. Analysis of tissue sections revealed that the surface of ventricular tissue from WKHA rats was higher than that of WKY rats, without any enlargement of the cavity area. Analysis of isolated adult cells showed that cell width (as well as cell volume) of ventricular cardiomyocytes was significantly higher in WKHA than WKY rats. However, LV of WKHA rats contained approximately 33% less cardiomyocytes than those from WKY rats. Mean intracellular free calcium concentration of cardiomyocytes was also higher in WKHA than WKY rats. Hemodynamic measurements revealed that the values of the maximum rates of pressure change (dP/dt) were higher in LV from WKHA rats. However, these differences were reduced (-dP/dt) or abolished (+dP/dt) when the values were normalized for both the number and mean cross-sectional area of ventricular cardiomyocytes. Mean levels of systolic and diastolic blood pressure (corresponding to the 24-h average of measurements obtained continuously in conscious unrestrained animals using radiotelemetric implants) were not different between strains. However, circadian rhythm was more evident in WKY rats, because the difference between morning and night values of systolic and diastolic blood pressure was greater (by 3 mmHg) in WKY rats. Altogether, our data validate the use of WKHA rats as models of predominantly concentric LV hypertrophy developing in the absence of increased mean levels of hemodynamic cardiac load and show that the hypertrophy phenotype is more pronounced in isolated cardiomyocytes than at the level of the whole ventricle.

Animals↗
PubMed2005

Heterogeneity of hepatitis C virus genotype 4 strains circulating in south-western France.

Hepatitis C virus (HCV) is a major cause of liver disease. Knowledge of HCV variability is crucial for clinical and epidemiological analysis. HCV genotype 4 (HCV-4) has become increasingly prevalent in European countries, including France, in recent years. The present study investigates the heterogeneity of HCV-4 in south-western France by phylogenetic analysis of NS5B sequences from 166 patients. The E2 region of 90 strains was also analysed. Genotype 4 accounts for 7.4 % of HCV infections in this area. Analysis of the NS5B region revealed 12 subtypes and the NS5B and E2 phylogeny data were congruent, except for one strain. The epidemiological data indicated two main groups of patients. One included intravenous drug users (IVDUs) of French origin, who were infected by homogeneous strains of subtypes 4a or 4d. The second group comprised non-IVDU patients who were infected with heterogeneous strains. This group was subdivided into patients of French origin, who were infected with eight subtypes, and patients from non-European countries (Central Africa or the Middle East), who were mainly infected with 4f, 4k, 4r and other subtypes; they showed the greatest genetic heterogeneity. This study of a large cohort of patients shows the great diversity of HCV-4 strains, and that these subtypes have spread differently.

Adult↗
PubMed1992

Urban/rural and deprivational differences in incidence and clustering of childhood diabetes in Scotland.

Scottish hospital discharges were monitored during the period 1977-1983 for new cases of diabetes in children aged 18 years or under. An estimated ascertainment rate of 94% was obtained by validation against an independent register of cases. The postcode sector at the time of admission was available for 2125 (97%) of the 2183 cases, and was used as the basis for a small-area analysis of urban/rural and socioeconomic differences in incidence and to test for clustering. Incidence rates standardized for age and sex showed important differences between the 16 Scottish postcode areas. At the sector level, the standardized rate was 20% lower in urban sectors compared to rural sectors, but this could be explained by area to area differences and by socioeconomic effects within areas. In contrast, significant socioeconomic differences in incidence were evident within areas which could not be explained by urban/rural effects, the children in deprived sectors having 80% of the risk of those in other sectors. Rates were particularly low among children in deprived urban sectors. Nevertheless, significant variations in incidence remained between the 16 areas which could not be explained by either urban/rural or socioeconomic differences, indicating the existence of other important factors. Tests for clustering of cases both within postcodes sectors and across adjacent postcode sectors were also performed. Although clusters could be identified, they were no more common than would be expected by chance. Tests for space-time clustering were also negative.

Adolescent↗
PubMed1998

Quantitative elemental X-ray imaging of frozen-hydrated biological samples.

It is shown that quantitative X-ray imaging of planed, frozen-hydrated, biological bulk samples that have not been etched is possible. X-ray imaging represents a better alternative to static beam (selected area) analysis of fractured frozen-hydrated samples. This procedure avoids the undesirable necessity of etching planed frozen-hydrated samples to provide an interpretable electron image. Qualitative oxygen and carbon X-ray images, which can be acquired in a short time, can be used for distinguishing morphological features and remove the requirement for electron images. In test samples of frozen-hydrated albumin, containing salts, analyses by X-ray images compared well with static beam (selected area) analyses from the same samples. An example of an analysis of frozen-hydrated insect Malpighian tubules is given in which the response to ouabain treatment was analysed. In this example X-ray imaging showed that ouabain resulted in a significant increase in cytoplasmic and luminal Na and a significant decrease in cytoplasmic and luminal K. X-ray imaging also showed that there was a significant increase in cellular water content. The presence of a potassium gradient in soybean root nodules was also demonstrated. The use of standard deviation images for processing low count images increases analytical precision but results in underestimates of the true concentrations.

Animals↗
PubMed1980

Cross-sectional echocardiography. II. Analysis of mathematic models for quantifying volume of the formalin-fixed left ventricle.

Cross-sectional echocardiography was used to quantify volume in 21 canine left ventricles that were fixed in formalin and immersed in mineral oil. Area, length and diameter measurements were obtained from short- and long-axis cross-sectional images of the left ventricle and volume was calculated by seven mathematic models. Calculated volume was then compared, by linear regression and percent error analyses, with fluid volume of the left ventricle, obtained by filling the chamber with a known amount of fluid. Volumes ranged from 13-146 ml. Mathematic models using short-axis area and long-axis length gave higher correlation coefficients (r = 0.982 and r = 0.969) and lower mean errors (10-20%) than standard formulas previously used for M-mode echo and angiography. Thus, short-axis area analysis with cross-sectional echocardiography is well-suited for quantifying left ventricular volumes in dogs.

Animals↗
PubMed1993

Value of a simple measure of estrogen status for improving the diagnosis of coronary artery disease in women.

PURPOSE: To determine the potential impact of estrogen status on the pretest and postexercise test diagnostic accuracy of exercise testing. PATIENTS AND METHODS: The study comprised a total of 234 women and 326 men who underwent exercise testing followed by coronary angiography. We performed incremental logistic regression analysis of pretest (age, symptoms, smoking, diabetes, cholesterol level) with and without estrogen status (defined according to menopausal and oral estrogen status) and exercise test (two ST-segment and three non-ST-segment) variables separately for men and women. Outcomes were assessed by receiver operating characteristic (ROC) curve area analysis. RESULTS: Estrogen status was an independent pretest predictor of angiographic coronary disease. Pretest ROC curve areas: women without estrogen status = 0.79, women with estrogen status = 0.85, men = 0.78 (women with estrogen status versus other groups, p < 0.001). Postexercise test ROC curve areas: women without estrogen status = 0.83, women with estrogen status = 0.87, men = 0.88 (women without estrogen status versus other groups, p < 0.001). CONCLUSION: Consideration of estrogen status allowed for a significant improvement in the pretest clinical diagnosis of coronary disease in women. When these improvements were added to the results of exercise testing, the diagnostic accuracy of the combined clinical and exercise test data was similar for men and women. Estrogen status may be an important diagnostic clinical variable in women with suspected coronary disease.

Adult↗
PubMed1996

Validation of estrogen status as an independent predictor of coronary artery disease presence and extent in women.

OBJECTIVE: To validate the independent nature and incremental value of estrogen status concerning the diagnostic evaluation of women with suspected coronary artery disease. DESIGN AND METHODS: The study comprised a total of 1,168 patients, the first 915 of whom served as a training or derivation population. Data from the subsequent 253 patients were prospectively collected and used to validate observations from the derivation group. We performed logistic regression analysis of age, sex, symptoms, smoking habits, diabetes, hypertension, and other variables with and without estrogen status (defined according to menopausal and estrogen replacement status). Diagnostic outcomes were assessed by receiver-operating characteristic curve area analysis. RESULTS: Within the derivation group, estrogen status was an independent predictor of both significant (> or = 1 lesion > or = 50% stenosis) and serve (at least two vessels with > or = 70% stenosis) coronary disease on angiography. Receiver-operating characteristic curve areas for models applied to the validation group were as follows: women without estrogen status, 77 +/- 4 for significant disease and 76 +/- 5 for severe disease; women with estrogen status, 80 +/- 4 for significant disease and 80 +/- 5 for severe disease; men, 72 +/- 4 for significant disease and 74 +/- 4 for severe disease (women with versus women without estrogen status; P < 0.05). CONCLUSION: Estrogen status has significant incremental value for enhancing the diagnostic discrimination of significant and severe coronary disease in women. Estrogen status, as defined in this study, is an important and independent diagnostic clinical variable in women with suspected coronary disease.

Coronary Disease↗
PubMed2003

An estimation of Toxocara canis prevalence in dogs, environmental egg contamination and risk of human infection in the Marche region of Italy.

The human risk of infection with larvae of Toxocara canis was estimated in people from the Marche region of Italy. This region includes both urban and rural areas and its inhabitants frequently keep dogs for company, hunting, as guardians or shepherds. T. canis infection was diagnosed in 33.6% out of 295 dogs examined. Nearly half of the dogs (48.4%) living in rural areas were found T. canis positive, compared to about one-quarter of the dogs (26.2%) from urban areas. Analysis by provenance and role revealed the highest infection rate in rural hunting dogs (64.7%) and the lowest in urban companion dogs (22.1%). According to questionnaire data, the peridomestic environment, i.e. gardens and dog pens, is the most important defecation site in both rural and urban areas. Since over 40% of the dogs who defecate in dog pens are infected and 24% of urban and 47% of rural dogs who leave their droppings in the house surroundings harbour the parasite, it is clear that these environments may constitute sites of zoonotic risk. Our analysis of soil samples from 60 farms confirmed the high contamination level, revealing positive soil samples in more than half of the farms. Substantial egg contamination was also found in urban areas, as 3/6 parks examined were Toxocara spp. positive. Finally, our serological findings indicate that human infection actually occurs in the area: 7 out of 428 adults examined (1.6%) had very high levels of antibodies to T. canis antigen, suggesting a previous contact with the Larva migrans of the nematode.

Animals↗
PubMed1999

Cost-effectiveness analysis of lambdacyhalothrin-treated nets for malaria control: the patients' perspective.

The present study was undertaken to evaluate the cost-effectiveness of lambdacyhalothrin-treated nets in comparison with conventional DDT-spraying as a method of malaria control according to the patients' perspective among migrant populations in a high-risk area along the Thai-Myanmar border in Thailand. Ten hamlets comprising 243 houses with 948 inhabitants were given only treated nets. Twelve hamlets comprising 294 houses and 1,315 inhabitants represented the DDT-treated area and another six hamlets with 171 houses and 695 inhabitants served as controls. Information as to consumer costs was obtained by interviewing 3,214 patients seeking care at all levels of the health care system in the study area. Analysis showed that the impregnated-net program was more cost-effective than the DDT-spraying program or surveillance alone (US$ 0.59 vs US$ 0.74 vs US$ 0.79 per 1 case of prevented malaria). We conclude that in a high-risk area such as along the Thai-Myanmar border in western Thailand, integrating the use of impregnated nets with large-scale primary health care programs is likely to constitute the most cost-effective method for controlling malaria according to the patients' perspective.

Bedding and Linens↗
PubMed1996

Titanium and bioactive glass-ceramic coated titanium as materials for keratoprosthesis.

The current problem with keratoprosthesis is the ingrowth of corneal or conjunctival epithelium into the anterior chamber. This may lead to infections and extrusion of the prosthesis as well as to the development of retroprosthetic membrane and secondary glaucoma. Glass-ceramic coated and uncoated titanium has been tested as material for the keratoprosthesis to prevent epithelial ingrowth. Twenty-two Supra-Descemet's membrane keratoprostheses were inserted in the eyes of 22 rabbits for 1, 2, 4, 8, or 12 months. The prosthesis had an optic part made of polymethylmetacrylate (PMMA). The support for the optic part and the flange of the prosthesis were made of titanium. Eleven of the prostheses were coated with glass-ceramic. The histological sections of the enucleated eyes were prepared through the central part of the cornea and the prosthesis using a cutting-grinding method. The histological analysis was made on both halves of the implants separately giving two analysis areas in each eye. All 11 titanium prostheses were retained for the time period planned. Two glass-ceramic coated prostheses were lost at 2 and 4 weeks, respectively. This was caused by difficulties at surgery due to a thick coating. These eyes were excluded from the histological analysis. No significant ingrowth of epithelium was seen in 15/18 (83%) and in 16/22 (73%) of the analysed areas of the glass-ceramic coated and titanium prostheses, respectively. Titanium appears to be a suitable material for the keratoprosthesis. The ingrowth of the epithelium may be hindered further by coating the titanium with bioactive glass-ceramic.

Animals↗
PubMed2006

Projection profile analysis for identifying different views of chest radiographs.

RATIONALE AND OBJECTIVES: For computerized analysis of chest images in the clinical environment, identification of frontal (posteroanterior/anteroposterior) and lateral chest radiographs is an important preprocessing step. In this study, we developed a method to distinguish frontal from lateral views of the chest radiographs based on an analysis of the projection profile. MATERIALS AND METHODS: Projection profile is obtained by projecting a chest image on to the mediolateral axis. Two indices, body symmetry index and background percentage index, are computed from the projection profile. The combination of body symmetry index and background percentage index is used to determine the view of chest radiographs. The method is evaluated on a sample of 2000 frontal and 1000 lateral chest images. RESULTS: The values of body symmetry index are found to be 1.18 +/- 0.23 and 3.07 +/- 1.42 for frontal and lateral chest images, respectively. The values of background percentage index are found to be 0.03 +/- 0.05 and 0.33 +/- 0.09 for frontal and lateral chest images, respectively. The discrimination is evaluated by linear discriminant analysis and receiver operating characteristic analysis. Area Az under the receiver operating characteristic curve with the combination of the two indices is 0.993. CONCLUSION: The method can be used as a preprocessing step for further analysis in chest radiographs.

Algorithms↗
PubMed2006

Two-dimensional echocardiographic methods for assessment of left atrial volume.

Left atrial (LA) size is an important predictor of cardiovascular events. Various methods of LA volume assessment exist, but their differences have not been defined. This prospective study included 631 patients (331 men; mean age of 68 +/- 14 years) without a history of atrial arrhythmias, stroke, valvular heart disease, pacemaker implantation, or congenital heart disease. All underwent echocardiography with comprehensive diastolic function assessment and LA volume measurement by 3 commonly used methods: biplane area-length, biplane Simpson's method, and the prolate-ellipsoid method. Mean LA volumes were 39 +/- 14 ml/m2 by the area-length method, 38 +/- 13 ml/m2 by the Simpson's method, and 32 +/- 14 ml/m2 by the prolate-ellipsoid method. In 92% of patients, the prolate measurement was smaller than the 2 biplane methods. Pairwise correlations (r) were 0.98 for area-length versus Simpson's, 0.85 for prolate versus area-length, and 0.86 for prolate versus Simpson's (all p values <0.001). For distinguishing normal (n = 62) from pseudonormal diastolic function (n = 240) using receiver-operating curve analysis, areas under the curves were 0.76, 0.78, and 0.75 for the area-length, Simpson's, and prolate methods, respectively (all p values <0.001, no significant intermethod differences). In conclusion, our findings suggest that there are systematic differences among existing LA volume methods. Biplane area-length and Simpson's methods compare closely, whereas the prolate-ellipsoid method generally yields smaller volumes.

Adolescent↗
PubMed2002

A novel particle engineering technology to enhance dissolution of poorly water soluble drugs: spray-freezing into liquid.

A novel cryogenic spray-freezing into liquid (SFL) process was developed to produce microparticulate powders consisting of an active pharmaceutical ingredient (API) molecularly embedded within a pharmaceutical excipient matrix. In the SFL process, a feed solution containing the API was atomized beneath the surface of a cryogenic liquid such that the liquid-liquid impingement between the feed and cryogenic liquids resulted in intense atomization into microdroplets, which were frozen instantaneously into microparticles. The SFL micronized powder was obtained following lyophilization of the frozen microparticles. The objective of this study was to develop a particle engineering technology to produce micronized powders of the hydrophobic drug, danazol, complexed with hydroxypropyl-beta-cyclodextrin (HPbetaCD) and to compare these SFL micronized powders to inclusion complex powders produced from other techniques, such as co-grinding of dry powder mixtures and lyophilization of bulk solutions. Danazol and HPbetaCD were dissolved in a water/tetrahydrofuran cosolvent mixture prior to SFL processing or slow freezing. Identical quantities of the API and HPbetaCD used in the solutions were co-ground in a mortar and pestle and blended to produce a co-ground physical mixture for comparison. The powder samples were characterized by differential scanning calorimetry (DSC), powder X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), scanning electron microscopy, surface area analysis, and dissolution testing. The results provided by DSC, XRD, and FTIR suggested the formation of inclusion complexes by both slow-freezing and SFL. However, the specific surface area was significantly higher for the latter. Dissolution results suggested that equilibration of the danazol/HPbetaCD solution prior to SFL processing was required to produce the most soluble conformation of the resulting inclusion complex following SFL. SFL micronized powders exhibited better dissolution profiles than the slowly frozen aggregate powder. Results indicated that micronized SFL inclusion complex powders dissolved faster in aqueous dissolution media than inclusion complexes formed by conventional techniques due to higher surface areas and stabilized inclusion complexes obtained by ultra-rapid freezing.

Freezing↗
PubMedDate not supplied

[Environment and health status of the population in areas with high risk of environmental crisis in Italy].

The Italian Ministry of Environment identified 15 areas throughout the country as at "high risk of environmental crisis". The areas host industrial activities that may entail noxious exposures, through occupation and the environment. An epidemiological descriptive study on the residents was carried out using routinely collected mortality data. Mortality data for the period 1981-1994 at the level of municipality were analysed, for around 30 causes of death for both sexes. Methods for small area analysis and disease mapping were used. Rates and SMRs (also adjusted for socio-economic factors) were tabulated for residents and restricted to people born locally. The geographical distribution within areas, time trends, and birth cohort effects were also investigated. Results for some specific areas indicate excesses that can be ascribed to known exposures. The mortality of the residents of areas taken together is substantially higher than expected; significant excesses are more than can be predicted by chance. Due to the heterogenous nature of the risk factors, no common patterns of mortality were observed, but for example 50% of the SMRs for total mortality calculated in the areas, for men and women separately, were significantly greater than unity, and so were 37% of the SMRs for all cancers and 30% for lung cancer. Relative risks were in general of small magnitude, but as populations are large (the areas include some 3.5 million people) and mortality is increased for common causes, absolute numbers of excess deaths were large. These results indicate the occurrence of important risk factors, some of which are related to the industrial activities, but more detailed data are needed for the identification of corrective public health actions.

Cause of Death↗
PubMed1980

Regional variation of cell proliferation within the facial processes of the chick embryo: a study of the role of 'merging' during development.

Variation in rates of cell proliferation along the long axis of the maxillary process, within the lateral nasal process and in the zone of attachment between these structures was analyzed employing DNA labeling indices. Chick embryos were labeled with [3H]thymidine for 1 h and processed for histology and autoradiography. The percentage of labeled mesenchymal cells was determined in delineated areas. Analysis of labeling indices indicated that rates of cell proliferation varied within each of the facial processes. Regions where rates of proliferation were maintained at elevated levels were the boundary areas of the facial processes (e.g. the anterior tip of the maxillary process) and the zones of attachment between the facial processes (e.g. between the maxillary process and the lateral nasal process). Despite the presence of elevated rates of proliferation in selected regions within the facial processes, however, the percentage of labeled cells in all areas declined with advancing developmental age. These findings support the hypothesis, proposed by Streeter and Patten, that the 'merging' of adjacent facial primordia, such as the maxillary and lateral nasal processes, is accomplished by elevated rates of cell proliferation within the zones of attachment compared to the rates of proliferation in adjacent regions.

Animals↗
PubMed2000

Associations among hospital capacity, utilization, and mortality of US Medicare beneficiaries, controlling for sociodemographic factors.

OBJECTIVE: To explore whether geographic variations in Medicare hospital utilization rates are due to differences in local hospital capacity, after controlling for socioeconomic status and disease burden, and to determine whether greater hospital capacity is associated with lower Medicare mortality rates. DATA SOURCES/STUDY SETTING: The study population: a 20 percent sample of 1989 Medicare enrollees. Measures of resources were based on a national small area analysis of 313 Hospital Referral Regions (HRR). Demographic and socioeconomic data were obtained from the 1990 U.S. Census. Measures of local disease burden were developed using Medicare claims files. STUDY DESIGN: The study was a cross-sectional analysis of the relationship between per capita measures of hospital resources in each region and hospital utilization and mortality rates among Medicare enrollees. Regression techniques were used to control for differences in sociodemographic characteristics and disease burden across areas. DATA COLLECTION/EXTRACTION METHODS: Data on the study population were obtained from Medicare enrollment (Denominator File) and hospital claims files (MedPAR) and U.S. Census files. PRINCIPAL FINDINGS: The per capita supply of hospital beds varied by more than twofold across U.S. regions. Residents of areas with more beds were up to 30 percent more likely to be hospitalized, controlling for ecologic measures of socioeconomic characteristics and disease burden. A greater proportion of the population was hospitalized at least once during the year in areas with more beds; death was also more likely to take place in an inpatient setting. All effects were consistent across racial and income groups. Residence in areas with greater levels of hospital resources was not associated with a decreased risk of death. CONCLUSIONS: Residence in areas of greater hospital capacity is associated with substantially increased use of the hospital, even after controlling for socioeconomic characteristics and illness burden. This increased use provides no detectable mortality benefit.

Aged↗
PubMed2002

Chlamydophila pneumoniae (Chlamydia pneumoniae) accelerates the formation of complex atherosclerotic lesions in Apo E3-Leiden mice.

OBJECTIVE: Atherosclerosis is an inflammatory process and is characterised by the presence of T-lymphocytes in the lesions. To study the role of Chlamydophila pneumoniae (C. pneumoniae) in this process and the effect of infection on T-cell influx, we infected Apo E3-Leiden mice with C. pneumoniae and investigated the effect on lesion development and T-cell influx in atherosclerotic lesions at different time points post infection (pi). METHODS: Nine week old mice, fed an atherogenic diet, were either mock-infected or infected with C. pneumoniae and sacrificed at 1, 6 and 9 months pi. Longitudinal sections of the aortic arches of the mice were stained with hematoxylin-eosin for atherosclerotic lesion type and lesion area analysis, or with rabbit-anti-CD3(+) to detect the presence of T-cells in the atherosclerotic lesions. T-cell influx was expressed as number of T-lymphocytes/lesion area. RESULTS: At 1 month pi, type 1, 2 and 3 lesions were present. At other time points pi, more complex lesion types 4, 5a and 5b were also present. Although infection did not influence the total lesion number or area, we observed an effect of C. pneumoniae infection on lesion type. Infection resulted in a significant shift in lesion formation from type 3 to type 4 (P=0.022) at 6 months pi, and from type 4 to type 5a (P=0.002) at 9 months pi. T-cells were observed at every time point pi. At 1 month pi, a significant increase in T-cell influx in the C. pneumoniae-infected atherosclerotic lesions was observed (P=0.0005). CONCLUSION: This study shows that C. pneumoniae infection enhances the inflammatory process by increasing T-lymphocytes in the plaque and accelerates the formation of complex lesions.

Animals↗
PubMed1999

Influence of age on the multifocal electroretinography.

The influence of age on the amplitude density (nV/sq deg) of the multifocal electroretinogram (ERG) was studied in 90 healthy subjects aged 18-52 years. Subjects were divided into three separate age groups; (i) 18-22 years (ii) 33-37 years and (iii) 48-52 years. Amplitude density of first order kernel of the multifocal ERG was measured for the three different age groups. When the whole response of the retina is considered, analysis of variance showed no significant differences in amplitude density between the three age groups. (ANOVA, df. 2, 87 F = 2.29, p = 0.11. However if the responses were segregated into a central area and concentric rings around the central area, analysis of variance showed that there were significant differences in responses between rings at different eccentricities and between different age groups (Anova F = 76.19, df. 17, 522, p = 0.00001). Post hoc analysis showed that the responses from the centre and the second ring around the centre of fixation for 48-52 year olds were significantly lower than those responses from the 33-37 year old and the 18-22 year old age groups. The decline in the multifocal ERG in the central retina of the 48-52 year olds could be associated with the decline of the number of photoreceptors as the eye ages. Student t test revealed no significant differences in amplitude density between males and females.

Adolescent↗