AI-aided holographic flow cytometry for label-free identification of ovarian cancer cells in the presence of unbalanced datasets.

Liquid biopsy is a valuable emerging alternative to tissue biopsy with great potential in the noninvasive early diagnostics of cancer. Liquid biopsy based on single cell analysis can be a powerful approach to identify circulating tumor cells (CTCs) in the bloodstream and could provide new opportunities to be implemented in routine screening programs. Since CTCs are very rare, the accurate classification based on high-throughput and highly informative microscopy methods should minimize the false negative rates. Here, we show that holographic flow cytometry is a valuable instrument to obtain quantitative phase-contrast maps as input data for artificial intelligence (AI)-based classifiers. We tackle the problem of discriminating between A2780 ovarian cancer cells and THP1 monocyte cells based on the phase-contrast images obtained in flow cytometry mode. We compare conventional machine learning analysis and deep learning architectures in the non-ideal case of having a dataset with unbalanced populations for the AI training step. The results show the capacity of AI-aided holographic flow cytometry to discriminate between the two cell lines and highlight the important role played by the phase-contrast signature of the cells to guarantee accurate classification.

Serum concentration of homocysteine in spontaneous feline chronic kidney disease.

Serum homocysteine (Hcy) increases in people and dogs with chronic kidney disease (CKD). Hyperhomocysteinemia (HHcy) has also been associated with CKD-related hypertension and proteinuria. The aims of this study were to: (1) validate an enzymatic method for quantification of Hcy in feline serum; (2) evaluate whether HHcy was associated with the presence and severity of CKD, proteinuria or hypertension; and (3) determine whether HHcy could predict disease progression. The intra- and inter-assay coefficients of variation (CVs) and the recovery rates of linearity under dilution and spiking recovery tests of the enzymatic method were 3.1-6.7%, 11.6-12.5%, 96.9±5.4% and 96.9±5.4%, respectively. Healthy cats at risk of CKD (n=17) and cats with CKD (n=19) were sampled over a 6-month period (63 samples in total). Cats with CKD had significantly higher Hcy concentrations (P=0.005) than cats at risk. The concentration of Hcy was higher (P=0.002) in moderate-severe CKD than in mild CKD and correlated moderately with serum creatinine (P<0.0001; r=0.51). The concentration of Hcy increased with the magnitude of proteinuria and correlated weakly with urinary protein to creatinine ratio (P=0.045; r=0.26). HHcy was not associated with hypertension. At the time of enrollment, Hcy concentration was significantly higher (P=0.046) in cats that developed CKD compared to cats that remained stable. The enzymatic method for Hcy measurement in feline serum was precise and accurate. HHcy was relatively common in cats with advanced CKD and seemed to predict disease progression, but further studies are warranted.

Abdominal Obesity and Mobility Disability in Older Adults: A 4-Year Follow-Up the International Mobility in Aging Study.

BACKGROUND: Abdominal obesity is related to the disability process in older adults, however, little is known about this relationship when adjusted for important confounders such as depression and physical performance measures in a diverse international aged population. OBJECTIVES: To explore the longitudinal relationship between abdominal obesity and mobility disability controlling for physical performance and depression. DESIGN AND SETTING: Longitudinal observational study using data from the International Mobility in Aging Study (IMIAS) Study. PARTICIPANTS: 1104 out of 2002 older adults aged 64-74 years old free of mobility disability at baseline (2012) and then reassessed in 2016. MEASUREMENTS: Mobility disability was defined as reporting difficulty in walking 400 m or climbing stairs. Activities of daily living (ADL) disability was based on any self-reported difficulty in five mobility-related ADLs. Abdominal obesity was defined as waist circumference ≥ 88cm for women or ≥ 102 cm for men. Four meters gait speed, handgrip strength and depressive symptoms (CES-D) were assessed. Generalized Estimating Equations (GEE) and multinomial regressions were used to estimate associations between disability and abdominal obesity. RESULTS: 1104 free of disability participants were followed over 4 years, the mean age was 68.9 (±2.9) years among men and 68.7 (±2.6) years among women. Prevalence and incidence rates of mobility disability varied widely across research site and sex. The longitudinal associations between mobility disability and abdominal obesity remained significant even when adjusted by depressive symptoms, handgrip strength, gait speed, age, sex, education and research site. Participants with abdominal obesity had higher mobility disability (OR=1.68, 95% CI 1.23-1.76, p-value=0.01) and also increased risk for ADL disability (OR: 1.47, 95% CI 1.23-1.76, p-value=0.01). Abdominal obesity in baseline was also predictor of mobility disability in 2016 (OR: 1.93, 95% CI 1.17-3.17, p-value <0.01) but not for ADL disability (OR: 1.59, 95% CI 0.93-2.71, p-value =0.09) with accounting mortality. CONCLUSION: Abdominal obesity is associated longitudinally and predicts mobility disability, even over a short period (4 years) in community-dwelling older adults from different epidemiological contexts.

Association between High Levels of Parathyroid Hormone and Frailty: The Nepean Osteoporosis and Frailty (NOF) Study.

BACKGROUND: Frailty is associated with poor outcomes hence identification of risks factors is pivotal. Since the independent role of parathyroid hormone (PTH) in frailty remains unexplored, we aimed to determine this in a population of older individuals with a history of falling. DESIGN: Cross-sectional study. SETTING: Falls and Fracture Clinic, Nepean Hospital (Penrith, Australia). PARTICIPANTS: 692 subjects (mean age=79, 65% women) assessed between 2009-2015. MEASUREMENTS: Assessment included clinical examination, mood, nutrition, grip strength, gait velocity, bone densitometry and posturography. Chemistry included serum PTH, calcium, vitamin D (25(OH)D3), creatinine and albumin. Normocalcemic subjects were divided into 4 groups: (1) Normal: 25(OH)D3 >50nmol/L and PTH between 1.6-6.8pmol/L; (2) PTH responsive: low 25(OH)D3 (<50nmol/L) and high PTH (>6.8pmol/L); (3) PTH unresponsive: low 25(OH)D3 and normal PTH; (4) Hyper PTH (>6.8pmol/L) with normal 25(OH)D3. Frailty was defined using Fried's criteria. Difference between the groups was assessed using one-way ANOVA and X2 analysis. Multinomial logistic regression evaluated the association between the groups and the number of Fried's criteria adjusted for age, BMI, renal function, 25(OH)D3 levels, and albumin. RESULTS: 22.6% subjects had high PTH levels (>6.8pmol/L). All subjects in the high PTH groups had significantly lower grip strength, gait velocity, limits of stability, and higher BMI. The PTH responsive group had a higher risk of pre-frailty (ß=3.8, 95% CI = 3.42 - 5.22, p≷ 0.01) and frailty (ß=8.26, 95% CI = 2.8-16.1, p<0.01). The risk of frailty was also higher in the Hyper PTH group (ß=2.3, 95% CI = 1.74-4.32, p<0.01). CONCLUSION: We have reported an independent association of high PTH levels with high number of falls and with the clinical components of physical frailty in community dwelling older persons. Our results suggest a possible role of PTH in frailty that deserves further exploration.

FAM49B, a novel regulator of mitochondrial function and integrity that suppresses tumor metastasis.

Mitochondrial dysregulation plays a central role in cancers and drives reactive oxygen species (ROS)-dependent tumor progression. We investigated the pro-tumoral roles of mitochondrial dynamics and altered intracellular ROS levels in pancreatic ductal adenocarcinoma (PDAC). We identified 'family with sequence similarity 49 member B' (FAM49B) as a mitochondria-localized protein that regulates mitochondrial fission and cancer progression. Silencing FAM49B in PDAC cells resulted in increased fission and mitochondrial ROS generation, which enhanced PDAC cell proliferation and invasion. Notably, FAM49B expression levels in PDAC cells were downregulated by the tumor microenvironment. Overall, the results of this study show that FAM49B acts as a suppressor of cancer cell proliferation and invasion in PDAC by regulating tumor mitochondrial redox reactions and metabolism.

Comprehensive nutritional status in sarco-osteoporotic older fallers.

OBJECTIVES: In older persons, the combination of osteoporosis and sarcopenia has been proposed as a subset of frailer individuals at higher risk of falls and fractures. However, the particular nutritional status of the sarco-osteoporotic (SOP) patients remains unknown. The goal of this study was to obtain a comprehensive picture of nutritional status in SOP patients. DESIGN: Cross-sectional study. SETTING: Falls and Fractures Clinic, Nepean Hospital (Penrith, Australia). PARTICIPANTS: 680 subjects (mean age=79, 65% female) assessed between 2008-2013. MEASUREMENTS: Assessment included medical history, mini-nutritional assessment, physical examination, bone densitometry and body composition by DXA, and blood tests for nutritional status (albumin, creatinine, hemoglobin, vitamin D, vitamin B-12, calcium, phosphate and folate). Patients were divided in 4 groups: 1) osteopenia/osteoporosis (BMD<-1.0 SD); 2) sarcopenia; 3) SOP; and 4) normal (no sarcopenia/no osteoporosis). Difference between groups was assessed with one-way ANOVA and chi square analysis. Multivariable linear regression evaluated the association between the groups and measures of nutritional parameters. RESULTS: Sarcopenia was present in 47.4% of those with osteopenia (167/352) and 62.7% in those with osteoporosis (91/145). Mean age of the SOP was 80.4±7 years. SOP patients showed significantly higher prevalence of falls and fractures. Univariate analyses showed that SOP were more likely than normal to have a BMI< 25 (OR 2.42 95%CI 1.45-4.041, p<0.001), a MNA score <12 (OR 2.0, 95%CI 1.15-3.49, p<0.05), serum folate <20 nmol/L (OR 4.0 95%CI 1.35-11.87, p<0.01) and hemoglobin <120g/L (OR 2.0 95%CI 1.28-3.30, p<0.01). Multivariate analysis showed that a MNA score <12 was independently associated with SOP compared to normal when adjusted for age and gender. Hemoglobin <120g/L, BMI <25, and GDS >6 remained independently associated with SOP after adjustment for all variables including inflammatory conditions. Hypoalbuminemia (<35 g/L) was associated with just osteopenia/osteoporosis (OR: 2.03, 95%CI 1.08-3.81, p<0.01) and just sarcopenia (OR: 1.77, 95%CI 1.0-3.0, p<0.01) compared to normal. No differences in vitamin D, glomerular filtration rate, albumin, corrected calcium, phosphate, red blood cells folate or vitamin B12 levels were found between the subgroups. CONCLUSIONS: In approaching SOP patients, early prevention protocols directed to optimize their nutritional status would be a key strategy to prevent poor outcomes such as falls and fractures in this high risk population. Therefore, nutritional assessment and early nutritional supplementation should be essential domains in this strategy.

Association of neck circumference and obesity status with elevated blood pressure in children.

High blood pressure (BP) and overweight/obesity are increasingly prevalent in children. We examined the associations of excess weight indicators including neck circumference (NC) and body mass index (BMI) with high BP in children. We hypothesized that high NC is associated with elevated BP. We utilized cross-sectional anthropometric and BP data on 1058 children aged 6-18 years. Patients were classified into weight and NC categories according to published guidelines. Prehypertension was defined as systolic or diastolic BP levels between 90th and 95th percentile for gender, age and height. Hypertension signifies systolic and/or diastolic BP levels ≥ 95th percentile for age, gender and height. The prevalence of elevated BP was 29.2% (prehypertension=10.1%, hypertension=19.1%). The prevalence of overweight and obesity was 19.0 and 18.7%, respectively. Rates of wide NC increased progressively with BMI categories by 8.8, 29.4 and 68.7% among normal weight, overweight and obese children, respectively. Within each BMI category, the unadjusted odds ratio for elevated BP was significantly higher in children with wide NC than those with normal NC (normal weight OR=1.78 (1.0-3.1), P=0.04); overweight OR=2.74 (1.5-5.2), P=0.001); obese OR=2.44 (1.3-4.6), P=0.006)). Increasing NC and BMI are associated with elevated BP in children. Joint presence of wide NC and high BMI is associated with significantly high rates of elevated BP. NC measurement may be a helpful tool to detect the presence of elevated BP in children.

P.R.L. platelet rich lipotransfert: our experience and current state of art in the combined use of fat and PRP.

The authors report their experience about the use of P.R.L. PLATELET RICH LIPOTRANSFERT method (platelet rich plasma mixed fat grafting) in 223 patients affected by soft tissue defects (ulcers, Romberg syndrome, Hemifacial atrophy, loss of substance, and signs of aging). This paper introduces the reader to PRP therapy and reviews the current literature on this emerging treatment modality, showing at the current clinical use of PRP in plastic and reconstructive surgery, with description of innovative methods and future prospects. This technique provides a promising alternative to surgery by promoting safe and natural healing. Here recent studies concerning the use of PRP in the treatment of chronic ulcers and soft tissue defect are reviewed.

HCG hastens both the development of mammary carcinoma and the metastatization of HCG/LH and ERBB-2 receptor-positive cells in mice.

Breast cancer is more frequent in human nulliparae, whereas its incidence is reduced by early fullterm pregnancy. Rodent studies suggest that chorionic gonadotropin secretion during pregnancy affords protection by inducing breast structure differentiation. Opposite effects, however, have been observed in cancer prone transgenic mice overexpressing the ß subunit of chorionic gonadotropin or pituitary luteinic hormone (LH). Here we assessed the effect of administration of human chorionic gonadotropin (hCG) for 21 days (corresponding to the duration of a mouse pregnancy) in virgin female mice transgenic for the activated rat (r-) ERBB-2 oncogene (BALB-neuT). In these mice, the onset of atypical mammary duct hyperplasia and its progression towards multiple mammary carcinomas is accelerated by hCG. hCG enhances the in vitro proliferation and in vivo metastatization of tumor cells from a BALB-neuT mammary tumor expressing the hCG/LH as well as the ERBB-2 receptors. These findings suggest that hCG favours the growth and progression of hCG/LH and ERBB-2 receptor-positive breast tumors.

Dizziness as a geriatric condition among rural community-dwelling older adults.

BACKGROUND: Dizziness is a common symptom in older adults. The majority of those with dizziness tend to have more than one risk factor, suggesting that dizziness is a multifactorial geriatric condition. Therefore, associated factors must be determined to permit risk-reduction approaches. OBJECTIVE: To examine the associations between dizziness and socio-demographic, physical, functional and psychological health factors among older persons living in the Andes Mountains. DESIGN: Population-based cross-sectional study. SETTINGS/PARTICIPANTS: One thousand six hundred ninety-two community-living people aged 60 years and over living in four rural and suburban areas of villages in coffee-grower zones in the Colombian Andes Mountains. MEASUREMENTS: Outcome measures included self-reporting of dizziness as a symptom experienced either very frequently or continuously during the last month. Independent variables were demographic, socioeconomic and social factors; disease and biomedical factors; functional status and performance-based measures; and psychological factors such as depressive symptoms and self-rated health. RESULTS: Dizziness was reported by 15.2% of participants in the study. Variables independently associated with dizziness were: number of chronic conditions, visual impairment, and use of more than four medications. Independently associated psychological variables were: poor self-perceived health, cognitive impairment and depression. Health and psychological factors accounted for 85% of dizziness. CONCLUSION: Older persons who reported dizziness were more physically frail, with more instances of chronic conditions and sensory impairments, and had poor self-perceptions of their health. Biomedical and psychological factors showed a strong independent association with dizziness. A multifactorial intervention targeting the identified factors would reduce dizziness in older people. However, this approach may need to address different sets of specific factors related to the dizziness categories.

DNA immunization using constant-current electroporation affords long-term protection from autochthonous mammary carcinomas in cancer-prone transgenic mice.

A recently developed, adaptive constant-current electroporation technique was used to immunize mice with an intramuscular injection of plasmid coding for the extracellular and transmembrane domains of the product of the rat neu(664V-E) oncogene protein. In wild-type BALB/c mice, plasmid electroporation at lower current settings elicits higher antibody titers, a strong cytotoxic response and completely protects all mice vaccinated with 10, 25 and 50 microg of plasmid against a lethal challenge of rat neu+ carcinoma cells. BALB/c mice transgenic for the transforming rat neu(664V-E) (ErbB-2, Her-2/neu) oncogene (BALB-neuT(664V-E)) develop an invasive mammary gland carcinoma by 20 weeks of age. Remarkably, when transgenic BALB-neuT(664V-E) mice were vaccinated at a 10- week interval with 50 microg of plasmid with 0.2 A electroporation, mice remained tumor free for more than a year. A single administration of plasmid associated with electroporation was enough to markedly delay carcinogenesis progression in mice with multiple microscopic invasive carcinomas, and keep about 50% of mice tumor free at one year of age. Thus, vaccination using a clinically relevant dose of plasmid encoding the extracellular and transmembrane domains of the neu oncogene delivered by electroporation prevents long-term tumor formation. These improvements in the efficacy of this cancer vaccine regimen vastly increase its chances for clinical success.

WIP null mice display a progressive immunological disorder that resembles Wiskott-Aldrich syndrome.

The Wiskott-Aldrich syndrome (WAS) is an X-linked immunodeficiency syndrome caused by mutations in the WAS protein (WASP). This participates in signalling and cytoskeletal homoeostasis, and some of its activities are regulated by its binding to the WASP interacting protein (WIP). WIP deficiency, however, has not yet been shown to be of pathological significance in humans. Here we show that, in WIP null (WIP(-/-)) mice, it produces haematological alterations and anatomical abnormalities in several organs, most probably as a consequence of autoimmune attacks. Granulocytosis and severe lymphopenia are associated with a proportional increase in segmented cells and fewer bone marrow erythrocytes and lymphocytes. Splenomegaly is accompanied by an increase of haematopoietic tissue and red pulp, reduction of the white pulp, and fewer B (B220(+)) lymphocytes (also apparent in the lymph nodes and Peyer's patches). Ulcerative colitis, interstitial pneumonitis, glomerular nephropathy with IgA deposits, autoantibodies, and joint inflammation are also evident. These progressive immunological disorders closely mimic those seen in WAS. WIP deficiency may thus be implicated in some cases in which mutations in the gene encoding WASP are not detected.

Plasma apolipoproteins and risk for age related maculopathy.

AIM: To determine if elevated plasma levels of atherogenic and/or anti-atherogenic lipoproteins are risk factors for developing age related maculopathy (ARM). METHODS: In a cross sectional study in a university clinic setting, 129 patients (72 women and 57 men) underwent colour fundus photography, acuity and contrast sensitivity assessment, and electroimmunoassays of plasma apolipoproteins B (apoB) and A-I (apoA-I), the principal proteins of low density and high density lipoproteins, respectively. Maculopathy stage was assigned using the AREDS grading system. RESULTS: Levels of apoB in no ARM, mild, intermediate, and advanced ARM groups were 93.3, 91.8, 95.2, and 98.2 mg/dl, respectively. Levels of apoA-I were 147.4, 148.6, 141.0, and 144.9 mg/dl in the same groups. There was no significant association between these measures, typical for age, and maculopathy stage. CONCLUSION: Although drusen associated with ARM and ageing contain cholesterol and apoB, like the lipid rich core of an atherosclerotic plaque, the results of this study and our previous work in toto make the prospects of a plasma origin for these lesion constituents increasingly untenable. This conclusion is consistent with an emerging hypothesis that a large lipoprotein of intraocular origin is an important pathway for constituent retinal lipid processing and the biogenesis of drusen.

The association between statin use and age related maculopathy.

AIMS: To evaluate the association between age related maculopathy (ARM) and statin use. METHODS: A nested case-control study among patients at the Veterans Affairs Medical Center in Birmingham, Alabama, with newly diagnosed ARM (cases) between 1997 to 2001 were selected and age matched to non-ARM controls. RESULTS: 550 incident cases of ARM were identified and matched to 5500 controls. Overall, cases were 70% (OR 0.30, 95% CI 0.21 to 0.45) less likely to have received and filled a statin prescription relative to the controls. This association was present among both current and past (OR 0.34, 95% CI 0.21 to 0.53 and OR 0.26, 95% CI 0.14 to 0.47, respectively) statin users. When considering use of statin and/or non-statin lipid lowering medications, a significant risk reduction was observed for statin only users (OR 0.30, 95% CI 0.20 to 0.45) and combined statin and non-statin users (OR 0.20, 95% CI 0.06 to 0.64); there was no significant association for non-statin only users (OR 0.47, 95% CI 0.20 to 1.13). CONCLUSIONS: The results of this study suggest that subjects with ARM were significantly less likely to have filled a statin prescription. Future clinical research initiatives should include a clinical trial to provide direct evidence of the effectiveness of statins in lowering the incidence and progression of ARM.

A novel dominant missense mutation--D179N--in the GJB2 gene (Connexin 26) associated with non-syndromic hearing loss.

Mutations of the GJB2 gene, encoding Connexin 26, are the most common cause of hereditary congenital hearing loss in many countries, and account for up to 50% of cases of autosomal-recessive non-syndromic deafness. By contrast, only a few GJB2 mutations have been reported to cause an autosomal-dominant form of non-syndromic deafness. We report on a family from southern Italy in whom dominant, non-syndromic, post-lingual hearing loss is associated with a novel missense mutation in the GJB2 gene. Direct sequencing of the gene showed a heterozygous G-->A transition at nucleotide 535, resulting in an aspartic acid to asparagine amino acid substitution at codon 179 (D179N). This mutation occurred in the second extracellular domain (EC2), which would seem to be very important for connexon-connexon interaction.

[Regional anesthesia in quadrantectomy and sentinel lymph node]. / Quadrantectomia e linfonodo sentinella in anestesia regionale.

After a brief mention about the mammary surgery, the Authors discuss the availability of regional anesthesia for quadrantectomy and "sentinel" node or axillary dissection.

Indication of hysteroscopy in tamoxifen treated breast cancer patients.

The aim of this study was to indicate the patients treated with tamoxifen for breast cancer in which hysteroscopy with biopsy should be considered mandatory. 414 breast cancer patients who underwent hysteroscopy with bioptic evaluation were enrolled in the study. 334 subjects were treated with 20 mg of tamoxifen daily as adjuvant therapy for six up to a hundred months. Of the remaining 80 control patients, which had not received tamoxifen, 30 were in premenopause (Group IA) and 50, in postmenopause (Group IIA). The tamoxifen-treated patients were subdivided in premenopausal (Group IB = 72 patients) and in postmenopausal (Group IIB = 262 patients) groups. All patients were further classified in asymptomatic or symptomatic groups considering whether uterine bleeding was absent or present. The evaluation of the endometrial mucosa was performed by office hysteroscopy. In group IIB patients presenting uterine bleeding, malignant lesions were found in 7.8% of the cases. The incidence of premalignant and malignant lesions in IIB patients treated for longer than 3 years (11.7%) was higher than that observed in IIB patients treated for less than 3 years (1.3%). There was a significant difference in terms of endometrial pathology between Group IIB (32.8%) and Group IIA (8%) (p < 0.001); and between Group IIB (32.8%) and Group IB (13.9%) women (p = 0.003). Among IA and IIA patients there were no cases of endometrial hyperplasia or cancer; on the contrary, in IB and IIB women, 2 and 22 cases of atypical hyperplasia were observed, respectively. All cases of endometrial cancer were observed in Group IIB and had a diagnosis of poor prognosis. In conclusion the hysteroscopy with biopsy should be considered the first diagnostic procedure to perform in tamoxifen-treated postmenopausal patients presenting uterine bleeding and in postmenopausal women treated for longer than 3 years. In premenopause, hysteroscopy should be proposed to women with ultrasonographic abnormalities and/or with uterine bleeding to patients at high risk for endometrial cancer.

Photoreceptor inner segments in monkey and human retina: mitochondrial density, optics, and regional variation.

The present work quantifies aspects of photoreceptor structure related to mitochondria, inner segment dimensions, and optical properties, as a basis for furthering our understanding of rod and cone function. Electron-microscopic analyses were performed on the retina of one stumptail macaque (Macaca arctoides) to obtain stereological measurements of ellipsoid mitochondrial density, and sizes and shapes of outer and inner segments. In addition, the distribution of mitochondria and the optical properties of human foveal cones were examined with electron microscopy and Nomarski differential interference contrast (NDIC) imaging. Mitochondria comprised 74-85% of cone ellipsoids and 54-66% of rod ellipsoids in macaque. Ellipsoid volume increased with eccentricity by 2.4-fold for rods and more than 6-fold for cones over eccentricities to 12.75 mm, while the volume of the outer segment supported by the ellipsoid was essentially constant for both rods and cones. Per unit volume of outer segment, cones contained ten times as much mitochondria as rods. In human fovea, as in the rest of the retina, most cone mitochondria were located in the distal inner segment. In the foveal center, however, there are also mitochondria in the myoid, as well as in the outer fiber, proximal to the external limiting membrane (ELM). Analyses of the optical aperture of human foveal cones, the point at which their refractive index clearly differs from the extrareceptoral space, showed that it correlated well with the location of mitochondria, except in the foveal center, where the aperture appeared proximal to the ELM. While mitochondria have an important metabolic function, we suggest that the striking differences between rods and cones in mitochondrial content are unlikely to be determined by metabolic demand alone. The numerous cone mitochondria may enhance the waveguide properties of cones, particularly in the periphery.

Murine high-fat diet and laser photochemical model of basal deposits in Bruch membrane.

OBJECTIVE: To examine the histologic, histochemical, and ultrastructural changes in Bruch membrane in mice on a high-fat diet with and without laser photochemical injury. METHODS: Five groups of C57BL/6 mice were studied. Group 1 included 2-month-old mice on a normal diet; group 2 included 8-month-old mice on a normal diet; group 3 included 8-month-old mice on a high-fat diet; groups 4 and 5 included 8-month-old mice on a normal diet or high-fat diet, respectively, that underwent laser application of one eye with argon blue laser (488 nm). The mice were killed and plasma lipid levels were measured. The eyes were examined by standard electron microscopy, filipin histochemistry for unesterified cholesterol (UC) and esterified cholesterol (EC), and the osmium-tannic acid-phenylenediamine method for preserving extracellular lipid particles. RESULTS: The plasma cholesterol level was significantly higher in the mice on the high-fat diet than the controls (P<.001). Bruch membrane was thicker in group 2 than group 1 (P =.04) and group 3 had a thicker Bruch membrane than group 2 (P =.003). All eyes in group 3 exhibited accumulation of electron-lucent debris. There was no histochemical and ultrastructural evidence that this material represented accumulated UC or EC. Seven of 9 laser-injured eyes in group 5 accumulated basal laminar deposit (BlamD)-like material in Bruch membrane (P =.02). CONCLUSIONS: Electron-lucent debris accumulates in murine Bruch membrane, and the amount correlates with age and high-fat diet. This debris has some similarities with basal linear deposits, although the debris does not form a discrete layer external to the basement membrane of the retinal pigment epithelium as occurs in basal linear deposits. These deposits do not appear to be UC or EC. Laser photochemical injury of the retinal pigment epithelium may result in the appearance of BlamD-like deposits in eyes with electron-lucent debris. The BlamD-like deposits in this model are similar to the basal laminar deposits that occur in age-related macular degeneration. CLINICAL RELEVANCE: This is an animal model of ultrastructural BlamD-like material in Bruch membrane that is very similar to the deposits that occur in age-related macular degeneration.