Urological anomalies in anorectal malformations in The Netherlands: effects of screening all patients on long-term outcome.

INTRODUCTION: Urological anomalies are frequently seen in patients with anorectal malformations (ARM) and can result in upper urinary tract deterioration. Whether the current method of screening is valid, adequate and needed for all patients is not clear. We, therefore, evaluated the urological screening methods in our ARM patients for changes in urological treatment, outcome and follow-up. METHODS: The medical records of 331 children born with an ARM in the period 1983-2003 were retrospectively studied. Documentation of diagnosis, screening method, urological anomalies, treatment, complications, follow-up and outcome were measured. RESULTS: The overall incidence of urological anomalies was 52%. The incidence of urological anomalies and urological follow-up time decreased with diminishing complexity of the ARM. Hydronephrosis, vesico-urethral reflux, lower urinary tract dysfunction and urinary incontinence were encountered most. Treatment invasiveness increased with the increase of complexity of an ARM. Lower urinary tract dysfunction needing urological care occurred in 43% in combination with lumbosacral or spinal cord anomalies and in 8% with no abnormalities in the lumbosacral-/spinal region. CONCLUSIONS: Urological anomalies in patients with complex ARM are more severe than in patients with less complex ARM. Ultrasonography of the urinary tract should be performed in all patients. Voiding cysto-urethrography can be reserved for patients with dilated upper urinary tracts, urinary tract infections or lumbosacral and spinal abnormalities. All patients with complex ARM need urodynamic investigations. When using these indications, the screening for urological anomalies in ARM patients can be optimized with long-term follow-up in selected patients.

Measurement of serum cytokine levels in patients with myelodysplastic syndromes.

Sera of 25 healthy controls and 75 patients suffering from myelodysplastic syndromes (MDS) were investigated for serum concentration of interleukin-1 alpha (IL-1 alpha), IL-3, IL-6, granulocyte-colony-stimulating factor (G-CSF), granulocyte-macrophage-CSF (GM-CSF), erythropoietin (Epo), and tumor necrosis factor-alpha (TNF-alpha). According to French-American-British (FAB) classification, 21 refractory anemia (RA), seven refractory anemia with ring sideroblasts (RARS), 15 chronic myelomonocytic leukemia (CMML), 12 refractory anemia with excess of blasts (RAEB), and 20 RAEB in transformation (RAEBt) were examined. TNF-alpha levels were inversely correlated with lower levels of hemoglobin concentration (r = -0.31, p = 0.005), irrespective of the requirements for transfusion in anemic MDS patients. Significant differences in TNF-alpha levels between CMML (26.2 +/- 5.9 pg/ml) and the FAB subgroups (16.1 +/- 1.6 pg/ml) were detected. There was an overall inverse relationship between the level of erythropoietin and the degree of anemia, but a wide range of Epo response between patients with similar hemoglobin concentrations. Serum levels of IL-1 alpha and GM-CSF were undetected in most of the patients. In 57% of the samples there were detectable levels of G-CSF, without a correlation of the serum levels with blood cell counts, nor with any of the FAB subcategories. Overall, 29% and 25% of the patient sera exhibited elevated IL-3 and IL-6 levels, respectively. There was no correlation of the serum levels with any of the blood counts, other cytokines, nor FAB subcategories. In conclusion, simple negative feedback mechanism between a specific cytokine and the production of blood cells seems not to be the case in MDS, except for red cell production and erythropoietin concentration. Our data may suggest the involvement of TNF-alpha in the pathogenesis of anemia in MDS.

Reducing salt in food; setting product-specific criteria aiming at a salt intake of 5 g per day.

BACKGROUND/OBJECTIVES: There is an increasing public health concern regarding high salt intake, which is generally between 9 and 12 g per day, and much higher than the 5 g recommended by World Health Organization. Several relevant sectors of the food industry are engaged in salt reduction, but it is a challenge to reduce salt in products without compromising on taste, shelf-life or expense for consumers. The objective was to develop globally applicable salt reduction criteria as guidance for product reformulation. SUBJECTS/METHODS: Two sets of product group-specific sodium criteria were developed to reduce salt levels in foods to help consumers reduce their intake towards an interim intake goal of 6 g/day, and­on the longer term­5 g/day. Data modelling using survey data from the United States, United Kingdom and Netherlands was performed to assess the potential impact on population salt intake of cross-industry food product reformulation towards these criteria. RESULTS: Modelling with 6 and 5 g/day criteria resulted in estimated reductions in population salt intake of 25 and 30% for the three countries, respectively, the latter representing an absolute decrease in the median salt intake of 1.8-2.2 g/day. CONCLUSIONS: The sodium criteria described in this paper can serve as guidance for salt reduction in foods. However, to enable achieving an intake of 5 g/day, salt reduction should not be limited to product reformulation. A multi-stakeholder approach is needed to make consumers aware of the need to reduce their salt intake. Nevertheless, dietary impact modelling shows that product reformulation by food industry has the potential to contribute substantially to salt-intake reduction.

Iodine and selenium deficiency associated with cretinism in northern Zaire.

Selenium status was determined in an endemic-goiter area and in a control area of Zaire. Compared with the reference values of a noniodine-deficient area, serum selenium in subjects living in the core of the northern Zaire endemic-goiter belt (Karawa villages) was seven times lower in 52 school-children and similarly low in 23 cretins; erythrocyte glutathione peroxidase (RBC-GPX) was five times lower in schoolchildren and still two times lower in cretins (P = 0.004). In a less severely iodine-deficient city of the same endemia (Businga), selenium status was moderately altered. RBC-GPX activity was linearly associated with serum selenium concentration up to a value of 1140 nmol/L and leveled off at approximately 15 U/g Hb at greater selenium concentration. At Karawa villages, selenium supplementation normalized both the serum selenium and the RBC-GPX. This combined iodine and selenium deficiency could be associated with the elevated frequency of endemic myxedematous cretinism in Central Africa.

Erythrocyte and leucocyte sodium and potassium transport systems during long-term diuretic administration in men.

The effect of xipamide on the intracellular concentration and transmembrane fluxes of Na+ and K+ was studied in 12 normal male subjects, using a double-blind cross-over design. After a run-in period on placebo for 1 week, the subjects were treated with either placebo (n = 6) or xipamide 20 mg once a day (n = 6) for 16 weeks and were then switched to the alternative medication for another 16 weeks. The intra-erythrocyte and intra-leucocyte Na+ concentration was increased by 11 and 7%, respectively, during xipamide administration, while the intracellular K+ concentration was decreased by 3 and 4%, respectively. No significant effect of xipamide could however be demonstrated on the ouabain-sensitive, bumetanide-sensitive or ouabain-bumetanide-resistant 86Rb uptake and on the maximal 3H-ouabain binding in erythrocytes and leucocytes. The red cell Na+-Li+ countertransport was also not changed in the xipamide-treated subjects. Our data suggest that the increased intracellular Na+ concentration and the decreased K+ concentration in red and white blood cells of xipamide-treated subjects cannot be attributed to changes in the activity of the Na+ pump, the Na+-K+ cotransport or Na+-Li+ countertransport system or to changes in the number of active Na+ pump units.

Racial differences in intracellular concentration and transmembrane fluxes of sodium and potassium in erythrocytes of normal male subjects.

Erythrocyte concentrations and fluxes of sodium and potassium were investigated in normal black and white male subjects. Erythrocyte sodium concentration was significantly elevated in blacks compared to whites. In single regression analysis erythrocyte sodium concentration was inversely related to the ouabain-sensitive 86Rb-uptake and to the frusemide-sensitive sodium efflux. After adjusting for race, only the relationship between the erythrocyte sodium concentration and the Na+, K+-ATpase pump activity persisted. The sodium-lithium countertransport system was also depressed in the black subjects. No significant difference was observed in erythrocyte potassium concentration between blacks and white. It is probable that, in blacks the decreased active influx of potassium through the sodium-potassium pump was to some extent counter balanced by a reduced efflux of this cationic mediated by the depressed cotransport system. There was no difference in cationic concentrations and fluxes of sodium and potassium between blacks bearing and not bearing haemoglobin S.

CD44H localization in primary open-angle glaucoma.

PURPOSE: Primary open-angle glaucoma (POAG) is associated with a decreased content of hyaluronan in the trabecular meshwork and in the juxtacanalicular connective tissue. In this study, the authors examined selected regions of the anterior segment to localize and determine the content of CD44H, a transmembrane multifunctional glycoprotein and the principal receptor of hyaluronan. METHODS: Sections of ethanol-fixed anterior segments of six POAG and six normal postmortem eyes were analyzed by immunostaining with and without the nonionic detergent Triton X-100, using the CD44H monoclonal antibody, and the avidin/biotin complex. They were visualized by Vector VIP substrate and were quantitated by computer-aided color image analysis. RESULTS: CD44H was expressed in all regions. Statistically significant decreased content of CD44H was observed in the POAG regions compared with normal regions--ciliary muscle (P < 0.001), ciliary stroma (P < 0.001), anterior iris (P < 0.05), iris root (P < 0.05), and trabecular meshwork (P < 0.05)--and in a subgroup of nonlaser POAG juxtacanalicular connective tissue (P < 0.05) and trabecular meshwork (P < 0.01). In sections treated with Triton X-100 a further increase in immunostaining was observed in normal eyes. As evidenced by scattergram plots of the ciliary body stroma region of the change in the optical density of CD44H between pretreatment with Triton X-100 and without Triton X-100 (y axis) versus the optical density of CD44H without Triton X-100 (x axis), individual cases of POAG were separated from normals. CONCLUSIONS: These results indicate that CD44H may represent a marker of POAG and an etiologic factor in the POAG disease process.

Glycosaminoglycan stratification of the juxtacanalicular tissue in normal and primary open-angle glaucoma.

PURPOSE: The juxtacanalicular tissue (JCT) is the probable site of aqueous outflow resistance in normal eyes and of the increased resistance in primary open-angle glaucoma eyes (POAG). The purpose of this histochemical study was to determine the glycosaminoglycan (GAG) composition and stratification in the JCT of POAG and age-matched normal eyes. METHODS: Five eyes from four normal donors and five eyes from four POAG donors (69 to 80 years of age) were analyzed. Using methods that histochemically preserve GAGs, GAG-degrading enzymes, Alcian blue staining, and real color discrimination to exclude pigment, nuclear staining and unstained areas, the type and amount of GAGs were estimated by compute-raided charge-coupled device color video image analysis. To examine GAG stratification, the JCT was segmented into three regions-anterior, middle, and posterior-to examine regional differences in GAG composition; each region was further divided into four 2-microns layers, from layer 1, adjacent to and including the endothelium of Schlemm's canal, to layer 4, to the first trabecular lamellae. RESULTS: The normal GAG JCT profile was as follows: hyaluronic acid (HA), 7.78 +/- 1.23 femtograms (fg)/micron2; chondroitin sulfates (CS), 8.18 +/- 0.82 fg/micron2; dermatan sulfate, 0.29 +/- 0.18 fg/micron2; the total, 18.73 +/- 0.68 fg/micron2. In contrast, the POAG GAG JCT profile was as follows: HA 0.57 +/- 0.31 fg/micron2 (P < 0.00001), a 93% decrease; CS 13.49 +/- 0.74 fg/micron2 (P < 0.0001), a 83% increase; dermatan sulfate, 0.90 +/- 0.53 fg/micron2; and the total, 17.31 +/- 0.95 fg/micron2, an 8.2% decrease. The HA was depleted in all layers of all regions of POAG JCT. CONCLUSIONS: Results indicate that the normal JCT is stratified, with HA as the predominant GAG in layers 1 and 2. The POAG JCT is depleted of HA and has an accumulation of CS, which may increase outflow resistance and, consequently, increase intraocular pressure in patients with POAG.

Fluorescence-labeled lectins, glycoconjugates, and the development of the mouse AOP.

The development of the aqueous outflow pathway (AOP) in early postnatal mouse eyes was examined for the presence of a variety of lectin receptors using fluorescein isothiocyanate (FITC) conjugated lectins, 1 micron araldite plastic sections, and computer-aided fluorescence photography. The trabecular meshwork anlage (days 1-4) was characterized by the presence of loosely arranged cells and an extracellular matrix that exhibited intense areas of Con A- and RCA-lectin staining, and absence of WGA- and LPA-lectin staining. By day 6, trabecular meshwork LPA- and WGA-positive materials were observed as focal areas of staining. By day 10, LPA- and WGA-positive materials were present as diffuse areas of staining, as the AOP differentiated into an organized and functional biological filter. The age-dependent pattern of LPA- and WGA-positive materials indicated that there were time-dependent points in the synthesis of glycoconjugates in the developing AOP. The results suggest: The composition and/or conformation of the glycoconjugates on cells and extracellular matrix changed as the AOP differentiated into a functional tissue. The use of FITC lectins as biological markers for studies of the AOP provided information on the potential role of glycoconjugates in the development of the normal AOP. Modification in the type, amount, and distribution of glycoconjugates may provide a basis for understanding the cellular mechanisms of abnormal development of the AOP, eg, congenital glaucoma.

Glycosaminoglycans of the human trabecular meshwork in primary open-angle glaucoma.

PURPOSE: Glycosaminoglycans (GAGs) contribute to the filtration barrier of aqueous outflow through the trabecular meshwork (TM). The purpose of this biochemical study was to identify the type and amount of GAGs in normal and in primary open-angle glaucoma (POAG) TM and adjacent anterior segment structures. METHODS: The GAGs of 21 masked individual normal and POAG human TMs, as well as iris, ciliary body, and anterior sclera, were isolated biochemically, identified by selective GAG-degrading enzymes, and quantitated by computer-enhanced densitometry. RESULTS: In 10 normal TMs (8 donors, 65 to 83 years of age), the GAG profile was: hyaluronic acid (0.77 +/- 0.26 ng/microgram dry-defatted weight +/- SEM); chondroitin 4(6-) sulfates and dermatan sulfate, collectively referred to as chondroitin sulfates (1.90 +/- 0.13 ng); keratan sulfates (0.33 +/- 0.06 ng); heparitin sulfates (2.02 +/- 0.52 ng); GAG enzyme-resistant material (0.02 +/- 0.01 ng); and total GAGs (5.05 +/- 0.70 ng). In 10 POAG TMs (6 donors, 67 to 88 years of age), the GAG profile was: hyaluronic acid (0.18 +/- 0.11 ng; P < 0.02, a 77% decrease; 6 of 10 TMs contained no detectable hyaluronic acid); chondroitin sulfates (2.39 +/- 0.31 ng); keratan sulfates (0.21 +/- 0.06 ng); heparitin sulfates (1.36 +/- 0.43 ng); GAG enzyme-resistant material (0.08 +/- 0.01 ng; P < 0.02); and total GAGs (4.09 +/- 0.33 ng; statistically insignificant). In the POAG iris, hyaluronic acid content was less (82% decrease, P < 0.02), and the chondroitin sulfates content was higher (72% increase, P < 0.02). Similarly, the POAG ciliary body and anterior sclera contained less hyaluronic acid and more chondroitin sulfates. The GAG profile of a "glaucoma suspect" donor specimen was similar to that of the POAG donor specimen. CONCLUSIONS: The data provide the first quantitative biochemical profiles of GAGs of individual normal and POAG TM, and we suggest that a depletion of hyaluronic acid and the accumulation of chondroitin sulfates may increase aqueous outflow resistance in the POAG TM:

Ultrastructure of cataract in myotonic dystrophy.

Four cataractous lenses from patients with myotonic dystrophy were studied by transmission electron microscopy. All lenses showed whorls of what appeared to be plasma membranes.

Effects of physical endurance training on the plasma renin-angiotensin-aldosterone system in normal man.

The effect of physical endurance training on the plasma renin-angiotensin-aldosterone system was studied in 27 normal sedentary volunteers aged between 20 and 55 years, using a randomized two-period cross-over study design. After 4 months of training (2.5 h/week), peak oxygen uptake and physical working capacity at a heart rate of 130 beats/min were increased by 16% (P less than 0.01) and 29% (P less than 0.001) respectively, whereas resting heart rate was decreased by 15% (P less than 0.001). The plasma noradrenaline concentration and haematocrit were both decreased (P less than 0.01) after training. For the total group of subjects, the small decreases in plasma renin activity (PRA) and in the plasma concentrations of angiotensin-I, angiotensin-II and aldosterone were not statistically significant. However, the change in PRA during the training period was negatively correlated with the increase in physical working capacity (r = -0.49, P less than 0.01), suggesting that PRA decreased only in those subjects with the greatest increase in exercise capacity. Also, the change in plasma aldosterone during training was negatively related to the rise in physical working capacity (r = -0.57, P less than 0.01). Furthermore, the changes in plasma angiotensin-I (r = 0.75), angiotensin-II (r = 0.49) and aldosterone (r = 0.43) during the training period correlated positively with the change in PRA. It is concluded that physical endurance training, leading to a substantial gain of physical working capacity, suppresses the plasma renin-angiotensin-aldosterone system in normal man.

Serum erythropoietin levels in elderly inpatients with anemia of chronic disorders and iron deficiency anemia.

OBJECTIVE: To analyze the relationship between serum erythropoietin levels and hemoglobin levels in elderly patients with anemia of chronic disorders related to cancer or acute infection when compared with anemic patients with iron deficiency. DESIGN: Prospective survey with comparison groups. SETTING: Tertiary care center. PATIENTS: An elderly group aged 70 and above (mean 84, range 70-96) was divided into subgroups of 45 with anemia of chronic disorders (23 with cancer and 22 with acute infection), 24 with iron-deficiency anemia, and 27 with no anemia. Thirty non-anemic younger adults were also studied. MEASUREMENTS: Serum erythropoietin (radioimmunoassay), complete blood count, serum iron, B12, folate and ferritin, liver and kidney function tests, blood gas analyses, and bacteriological and radiological tests. RESULTS: The serum erythropoietin levels were significantly lower in the elderly non-anemic hospitalized group than in the healthy younger group. A significant negative relationship between the log serum erythropoietin and hemoglobin levels was found in patients with iron deficiency, but not in the other groups. For any given hemoglobin level, the response of erythropoietin was significantly higher in anemic patients with iron deficiency when compared with the neoplastic and infectious group. CONCLUSION: Erythropoietin response to anemia is blunted in elderly patients with anemia of chronic disorders related to cancer or acute infection. Erythropoietin level is lower in non-anemic elderly inpatients than in healthy younger persons.

Ultrastructure of human cataract in retinitis pigmentosa.

A second ultrastructural study of retinitis pigmentosa cataract showed differences from the previous case with respect to sex, age of cataract onset, age at time of cataract extraction, and mode of inheritance of retinitis pigmentosa. Furthermore, the cataract in the present study was limited clinically and preponderantly ultrastructurally to the posterior subcapsular area, which is typical of the location of cataracts associated with retinitis pigmentosa. The cataract was characterized by severe lens fiber disorganization, resulting in intricately distorted membrane configurations and varying cytoplasmic densities; however, "figure eight" configurations as noted in the other report were not observed. Aberrantly migrated epithelial cells were distributed unevenly in the posterior subcapsular zone. New capsular basement membrane, not mentioned in the other report, was conspicuous in our case. Thus, retinitis pigmentosa cataract may have diverse ultrastructural alterations.

Monocyte counting: discrepancies in results obtained with different automated instruments.

To determine the accuracy of several methods for measuring the monocyte count, the results obtained by a number of different automated cell counters were analysed. Considerable discrepancies occurred for monocyte counts obtained in normal blood among the counters. The results of a visual monocyte count on a total of 800 leucocytes were used as the reference method. The technique of measuring the monocyte count by using dual staining with monoclonal antibodies CD45 and CD14 provided the closest agreement with the reference method. Six other automated counting systems were assessed. Two of these systems (Coulter VCS and Technicon H1) gave results, which, although under-estimating monocytosis, correlated well with the results obtained by the reference technique. A third system (Toa Sysmex NE-8000) gave unreliable results. Three of the automated systems evaluated measured a "third population"--that is, monocytes together with other leucocytes. One of these systems (Ortho ELT 1500), overestimated the count, as expected, but correlated well with the reference method. The second of these "third population counters" (Coulter S Plus IV) correlated moderately well with the reference monocytosis, while the Toa Sysmex E-5000 correlated poorly. It is clear that problems exist in the evaluation of different instruments for counting monocytes. An accurate and reliable reference method is a pre-requisite to evaluate this aspect of cell counters. As the visual method is too cumbersome a different reference method would be useful. Based on the results of this study, it is suggested that the technique using fluorescence labelled monoclonal antibodies should be regarded as an acceptable alternative.

Prolonged survival of allogeneic corneal grafts in rabbits treated with topically applied cyclosporin A: systemic absorption and local immunosuppressive effect.

The modes of action of topical cyclosporin A were studied in rabbits. Immunorejection of corneal allografts was provoked by placing the grafts eccentrically, in contact with the limbus. Topical application of cyclosporin A five times daily for 28 days prevented the rejection of corneal allografts. All grafts were rejected in the control animals. The seven rabbits of the cyclosporin A group were subsequently treated for six months with a lower dosage of cyclosporin A 1%. In six rabbits the graft remained clear. One rabbit treated with two drops a day showed an allograft reaction that could be suppressed by increasing the dosage. After six months, discontinuation of the therapy resulted in rejection of all grafts within four weeks. Cyclosporin A could be detected in the plasma and aqueous humour of both eyes at the end of the treatment, raising the question whether the immunosuppressive effect of topically applied cyclosporin A was due to local or systemic action. Cyclosporin A 1% was therefore applied to the fellow eye five times daily following transplantation, and this treatment, producing similar plasma levels of cyclosporin A, failed to delay the rejection of eccentric corneal allografts. Consequently the suppression of the allograft rejection by topical cyclosporin A is primarily a local immunosuppressive effect, though systemic influence is not ruled out.

Erythrocyte 2,3-diphosphoglycerate and serum enzyme concentrations in trained and sedentary men.

The acute effect of exercise on the intraerythrocyte 2,3-diphosphoglycerate concentration and on various serum enzymes and some related variables was investigated in 14 male athletes before and after a 50-min cross-country run and compared at rest to 15 sedentary subjects. Compared to the sedentary subjects, the athletes had higher resting levels of serum creatine phosphokinase, plasma myoglobin, and renin substrate but had a lower plasma renin activity. The red blood cell 2,3-diphosphoglycerate concentration increased after exercise in the runners and was not different at rest between the athletes and the sedentary subjects. Our data therefore suggest that the resting plasma renin activity is reduced in athletes when compared to sedentary subjects. Training seems however not to alter the resting level of 2,3-diphosphoglycerate in the red blood cells.

The presence of transcription factors in fetal bovine sera.

Three sources of fetal bovine serum (FBS) were fractionated by ammonium sulfate precipitation and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), transferred to Immobilon-P membranes, immunoblotted with a panel of transcription factor antibodies, and detected by enhanced chemiluminescence. Nine transcription factors were detected--ATF-2, SRE-ZBP, GATA-2, TFIID, Ets-1/Ets-2, E2F-1, Oct-2, p53, and AP-2; four transcription factors were not detected--Myo D, CREB, Sp2, and Wilms' tumor. The results indicated the presence of varying amounts of several transcription factors in three commercial sources and may represent heretofore unrecognized factors influencing cell culture.

The presence of transcription factors in chicken albumin, yolk and blastoderm.

Embryonic development is determined by preset intrinsic programs and extrinsic signals. To explore the possibility that transcription factors are present at the onset of development, preparations of yolk, albumin, and blastoderm from unfertilized and fertilized white Leghorn chicken eggs were screened by a panel of 16 transcription factor antibodies with Western blot techniques. Yolk was positive for 13 transcription factors, whereas blastoderm was positive for 10, and albumin was positive for 5. In yolk, several transcription factors, GATA-2, E2F-1, MyoD, and TFIID, were developmentally regulated. These results indicate that intracellular yolk and extracellular albumin contain transcription factors which presumably influence early chick embryonic development from prefertilization to the late blastoderm stage. Thus, the utility of preset maternal transcription factors within yolk and albumin complement maternally derived mRNA to determine the early development of the zygote.

An ultrastructural study of fixation artifacts in lens epithelium.

The conditions providing for optimal preservation of the ultrastructure of the lens epithelium of embryonic and young chicks were sought, especially with regard to avoiding fixation artifacts and to enhancing the lens cytoskeleton. The optimal fixative/buffer solution for these purposes was found to consist of 2% glutaraldehyde in 0.05M phosphate buffer containing 0.2% tannic acid and 0.002% CaCl2, pH 7.2, whose total osmolarity is about 340 mOsm, and postfixation in 1% osmium. As the osmolarity was increased by use of 0.075M or 0.1M phosphate buffer, intercellular spaces and myelin-like figures appeared along the cell membranes of the epithelial cells and superficial cortical fibers. As the osmolarity was decreased, using 0.02M phosphate buffer, plasma membranes became flaccid and interrupted, nuclei underwent severe shape changes, and the cytoplasm became electron-lucent. Delays of 30 minutes or one hour before fixation caused swelling of cytoplasmic organelles and the nuclear envelope. Primary fixation in osmium resulted in interrupted cell membranes and in swollen organelles. Many of these artifacts seen in the superficial chick lens, produced merely by manipulating the tonicity or the time of fixation after death, have been previously attributed in the literature to cataractous or aging changes. Based on the present findings caution in interpreting electron micrographs of pathologic changes in lens is urged.