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The present study pertains to the exploitation of biowaste generated through Banana (Musa acuminate L.) peels for the synthesis of green silver nanoparticles (AgNPs) and their bioactivity was evaluated for managing the dengue vector, Aedes aegypti. UV-VIS specrtophotometery was used for confirming AgNPs synthesis and a peak was observed at 426 nm. Characterization of AgNPs was done using Scanning electron microscopy which depicted spherical shape of AgNPs while Transmission electron micrographs revealed their size to be ranging from 20 to 50 nm. AgNPs bioactivity was studied against III instar larvae following 24, 48 and 72 h exposure and values of LC50 and LC90 were analyzed using probit analysis. LC50 values ranged from 10.69 to 25.15 ppm with AgNPs at various time exposures. Antioxidant potential of these AgNPs was also evaluated to supplement these findings. This study highlights the potential of biowastes as a potent larvicide against Aedes aegypti.

Bacteriophages that infect the foodborne pathogen Listeria monocytogenes were previously isolated from New York dairy farms. The complete genome sequences for three of these Listeria phages, with genome sizes of 64.6 to 65.7 kb, are presented here. Listeria phages LP-010, LP-013, and LP-031-2 are siphoviruses that belong to the genus Homburgvirus .

Transmission electron micrographs show the branchial epithelium of the ascidian Ciona intestinalis to be composed of three kinds of cells: ciliated, parietal, and "dark." Absorptive processes of phagocytosis appear in ciliated and parietal cells; moreover, apocrine-like secretion is evident exclusively in the parietal cells. Finally, the occurrence of secretory cells in the branchial epithelium suggests a digestive role of the ascidian branchial sac.

Silver nanoparticles (SNP) incorporated potassium oleate (KOL) soap by in situ reduction of silver nitrate by trisodium citrate (TSC) was described. Novel incorporation method of SNP into the natural rubber latex foam (NRLF) was successfully carried out by mixing 4 parts per hundred rubber (pphr) of SNP incorporated KOL soap in to the natural rubber latex (NRL) compound. UV-Visible spectrophotometer analysis, particle size analysis data and transmission electron micrograph analysis proved the modified KOL soap consisted of stable mono-dispersed nanometer size silver particles. SEM/EDX analysis of a latex film made out with modified NRL compound by SNP incorporated KOL soap shows nanosized silver particles inside it. Modified KOL and final product of modified NRLF by SNP incorporated KOL soap tested for antimicrobial properties against Escherichia coli (E. coli). The resultant KOL itself can inhibit Gram negative E. coli bacterium in a very strong manner. Inhibition of the same strain of E. coli bacterium ...

The reliable and reproducible quantitative image analysis of digital micrographs from high resolution transmission electron microscopy (HRTEM) of soot has been an area of interest since the early nineties. Since the resolution of HRTEM images is usually sufficient to carry out structural measurements at the atomic level, the information obtained from these images is very valuable as it potentially yields insight into very specific soot oxidation processes; however, extracting physically meaningful, reliable, accurate and statistically robust data from HRTEM images is not an easy process. Data extraction is hindered by the presence of overlapping structures, varying focus, contrast, illumination levels and noise in the images. In this paper a novel image analysis framework is presented to address these issues and explore the possibility of the extraction of high-fidelity structural data from HRTEM soot images. Emphasis is on the analysis of images of mostly amorphous, poorly ordered soot structures, as these are the most difficult to analyze.

Transmission electron micrographs of glycogen extracted from healthy mouse hearts reveal aggregate structures around 133 nm in diameter. These structures are similar to, but on average somewhat smaller than, the α-particles of glycogen found in mammalian liver. Like the larger liver glycogens, these new particles in cardiac tissue appear to be aggregates of β-particles. Free β-particles are also present in liver, and are the only type of particle seen in skeletal muscle. They have diameters from 20 to 50 nm. We discuss the number distributions of glycogen particle diameters and the implications for the structure-function relationship of glycogens in these tissues. We point out the possible implications for the study of glycogen storage diseases, and of non-insulin dependent diabetes mellitus.

Background: The mouse corneal stroma varies in thickness across its diameter. The purpose of the present study was to explain this variation and to advance our understanding of stromal lamellar architecture in the mammalian cornea. Methods: Eight C57BL/6 mice were killed, eyes enucleated, immersed in 2% glutaraldehyde fixative, processed and sectioned transversely for light and transmission electron microscopy. Transmission electron micrographs were assembled into montages and printed at 5000× magnification and used for lamellar counts and thickness assessments. Results: The mouse cornea had an average of 49.8 ± 2.4 lamellae centrally averaging 2.1 µm in thickness versus 35.5 ± 3.0 lamellae, averaging 1.9 µm in thickness peripherally. The central to peripheral decrease in number lamellae and lamellar thickness measured utilizing the transmission electron microscope was statistically significant (P

Examination of ciliary ultrastructure remains the cornerstone diagnostic test for primary ciliary dyskinesia (PCD), a disease of abnormal ciliary structure and/or function. Obtaining a biopsy with sufficient interpretable cilia and producing quality transmission electron micrographs (TEM) is challenging. Methods for processing tissues for optimal preservation of axonemal structures are not standardized. This study describes our experience using a standard operating procedure (SOP) for collecting nasal scrape biopsies and processing TEMs in a centralized laboratory. We enrolled patients with suspected PCD at research sites of the Genetic Disorders of Mucociliary Clearance Consortium. Biopsies were performed according to a SOP whereby curettes were used to scrape the inferior surface of the inferior turbinate, with samples placed in fixative. Specimens were shipped to a central laboratory where TEMs were prepared and blindly reviewed. Four hundred forty-eight specimens were obtained from 107 young children (0-5 years), 189 older children (5-18 years), and 152 adults (> 18 years), and 88% were adequate for formal interpretation. The proportion of adequate specimens was higher in adults than in children. Fifty percent of the adequate TEMs showed normal ciliary ultrastructure, 39% showed hallmark ultrastructural changes of PCD, and 11% had indeterminate findings. Among specimens without clearly normal ultrastructure, 72% had defects of the outer and/or inner dynein arms (IDA), while 7% had central apparatus defects with or without IDA defects. In summary, nasal scrape biopsies can be performed in the outpatient setting and yield interpretable samples, when performed by individuals with adequate training and experience according to an SOP.

Uniform design was adopted, and three factors, i.e., freezing rates with two levels, thawing rates with six levels and individual (six pork M. Longissimus dorsi from three pigs), were investigated. After thawing, thaw loss (TL), cook loss (CL), water-holding capacity (pressing loss) and protein solubility were measured. Structure was also viewed using transmission electron micrographs and scanning electron micrographs. The results showed that freezing rates, thawing rates and individual significantly affected TL and CL. Eliminating the effects of fixed factors of different individuals, the effects of thawing rates and freezing rates on TL and CL were nonlinear. Significant interactions between freezing rates and thawing rates on both TL and CL were observed. Water-holding capacity was correlated to different animals and was independent of freezing rates and thawing rates. Thawing rates and animal had some effects on total protein solubility (TPS) and myofibrillar protein solubility (MPS); however, freezing rates had almost no effects on them. Considering the CL, TL, TPS and MPS comprehensively, fast freezing rate and slower thawing rates (0.75 cm/h) were the optimal combination. Scanning electron micrograms of meat frozen at different freezing rates showed that ice crystals formed at different sizes and distribution. Slow freezing rates resulted in intercellular ice crystals, while quick freezing rates resulted in intracellular ice crystals. Freezing and thawing processing had some negative effects on the structure of meat. Thawed meat showed a reduction in the density of the Z-disks, and the overall integrity of the myofibril was lost; the quicker the thawing rates were, the more severe the disruption of the myofibril. PRACTICAL APPLICATIONS The freezing of meat has been widely used as an economically favorable way of storage, and generally, frozen meat should be thawed before it is used in the subsequent production. However, freezing procedures, frozen storage and the thawing procedures could affect meat quality attributes such as thaw loss, color and tenderness. Although there are many different methods of thawing, air thawing and water thawing are still the methods widely used in the food industry, especially in China, for its priority in price and convenience. Therefore, experiments were carried out to research the effect of freezing rate and thawing rate, which were similar to the present practice of the food industry in China. We found that fast freezing and low thawing were the optimal combination, which can decrease thaw loss, cook loss and pressing loss, and can maintain the functional properties of frozen pork meat. The result of our research was operable and very useful for both the food industry and the consumers to control the quality of frozen meat and to enhance the eating quality and the monetary value.

A novel nanoscale-dispersed eye ointment (NDEO) for the treatment of severe evaporative dry eye has been successfully developed. The excipients used as semisolid lipids were petrolatum and lanolin, as used in conventional eye ointment, which were coupled with medium-chain triglycerides (MCT) as a liquid lipid; both phases were then dispersed in polyvinyl pyrrolidone solution to form a nanodispersion. Single-factor experiments were conducted to optimize the formulations. A transmission electron micrograph showed that the ointment matrix was entrapped in the nanoemulsion of MCT, with a mean particle size of about 100?nm. The optimized formulation of NDEO was stable when stored for six months at 4??C, and demonstrated no cytotoxicity to human corneal epithelial cells when compared with commercial polymer-based artificial tears (Tears Natural??Forte). The therapeutic effects of NDEO were evaluated on a mouse model with ?dry eye?. Both the tear break-up time and fluorescein staining demonstrated therapeutic improvement, displaying a trend of positive correlation with higher concentrations of ointment matrix in the NDEO formulations compared to a marketed product. Histological evaluation demonstrated that the NDEO restored the normal corneal and conjunctival morphology and is safe for ophthalmic application.

Purpose. Due to a possible link in humans between atherosclerosis, a high-fat diet, and the development of age-related retinal degenerations, we investigated retinal changes with age and diet in high-fat-fed C57BL/6 mice, a mouse model of human atherosclerosis. Methods. We fed C57BL/6J mice either a normal chow diet or an atherogenic diet containing 15% total fat for either 15, 30 or 45 weeks. We sacrificed the animals and examined the eyes using fluorescence microscopy, light microscopy and transmission electron microscopy. Results. At 15 weeks, in high-fat-fed mice, there was an increase in the number of autofluorescent granules in the retinal pigment epithelium (RPE) compared to chow-fed mice. By light microscopy, we noted no remarkable differences in the inner retinal layers between mice fed either diet for 15 or 30 weeks. In contrast, we noted major changes in transmission electron micrographs from the 30 week high-fat group. In the RPE, these included: (1) an increase in the number and size of autop...

SummaryApples of cv. Golden Delicious were vacuum infiltrated with 300 mM mannitol, with or without 50 and 150 mM CaCl2. The fruits were stored under low temperature of 2–4°C for 100 d and sampled every 25 d for flesh firmness and transmission electron microscopy. The infiltration of the fruits with 150 mM CaCl2 resulted in higher retention of flesh firmness throughout the storage period, but with 50 mM CaCl2 this could be retained only up to 25 d. The content of insoluble calcium in the flesh increased with increase in the storage period. A large amount of the infiltrated calcium accumulated in walls. However, no relation could be observed between flesh firmness and the amounts of calcium associated with free, ionically bound and covalently bound pectin fractions of the walls. The transmission electron micrographs revealed that most of the changes appeared to involve the middle lamella, and flesh firmness can be judged from the visual inspection of the micrographs. It appears that the effect of calcium i...

Strain differences in midgut basal lamina thickness, assessed by measurement in transmission electron micrographs, and disseminated infection rates of dengue-1 virus were compared among three laboratory strains of Aedes albopictus (Skuse). Mean basal lamina thicknesses for the New Orleans and Houston strains were significantly greater than those for the Oahu strain, which exhibits a higher disseminated infection rate than the former two. Although basal lamina thickness among the F1 progeny of reciprocal crosses of the Oahu and Houston strains were intermediate between the parental strains, they were too variable to be useful as markers in genetic studies. Measurements of basal laminae among individuals of the New Orleans strain, with disseminated or nondisseminated infections, failed to demonstrate a role for basal lamina thickness as a modulator of dengue-1 virus dissemination across the midgut epithelium of Ae. albopictus.

Many glomerulopathies are characterized by progressive mesangial (interstitial) expansion which can be quantitated by morphometric analysis. The purpose of this study was to analyze mesangial and glomerular volumes using a new computer-assisted reconstruction (CAR) method. CAR was compared to two standard planar methods, point-counting and linear integration, for accuracy and time efficiency. In Phase I of the study, a computer-based model of the mesangial space was created by placing spherical and ellipsoidal objects of known volume into an enclosing volume mimicking the glomerulus. The simulated mesangium occupied approximately 10 percent of the glomerular volume. The model glomerulus was sectioned serially into ten sections of equal thickness and the three morphometric methods applied to determine the mesangial/glomerular volume. The complexity of the mesangial model was varied by increasing the number of mesangial regions from one to ten to 100. The CAR method estimated the model mesangial volume more accurately (1-9 percent error) through each level of complexity compared to point-counting (3-17 percent error) and linear integration (3-18 percent error). The point-counting method consistently overestimated (P less than 0.05) the fractional mesangial volume for the ten- and 100-region mesangium models. In Phase II of the study, a normal rat glomerulus was sectioned serially (215 sections) and a transmission electron micrograph (TEM) of every fifth section (n = 43) was obtained. Each TEM image (2% of glomerular surface) was digitized for analysis by CAR. Point-counting and linear integration were also performed on the whole glomerular TEMs (n = 10, randomly chosen). The estimated relative mesangial/glomerular volume was 6.6 +/- 0.1 percent by CAR (mean +/- SD), 9.7 +/- 1.5 by linear integration, and 14.9 +/- 3.4 by point-counting. The point-counting method was most efficient, requiring 40 +/- 8 sec/section, followed by CAR at 85 +/- 24 sec/section. Linear integration was least efficient (93 +/- 23 sec/section). We conclude that CAR is the most accurate morphometric method of the three compared for estimating mesangial and glomerular methods, although it is more time consuming than the point-counting method and requires more complex instrumentation. CAR is the only method that will analyze the shape and three-dimensional complexity of glomerular structures using TEMs.

Different forms of Normapolles from four anthers, retrieved from fluvial sediments in southeastern Sweden, have been studied by photomicroscopy, scanning electron microscopy and transmission electron microscopy. The exines are extremely resistant to staining and chemical treatment, probably as a result of increased polymerization, due to heating under oxygen‐deficient conditions in a wildfire (in combination with processes during fossilization and long burial). Substructurally, short straight or coiling structures and 10 nm wide sites, visible in transmission electron micrographs, are interpreted as fragments of helical strands constituting the bulk of the exine. Similar structures can be seen in scanning electron micrographs of pollen in chemically untreated anthers. Both scanning and transmission electron micrographs indicate that the 10 nm strands are formed by still smaller helical elements and that they may combine to form wider coiling structures. The exine has two main layers‐tectum and so...

We describe the presence of cylindrical spirals on muscle biopsy from a 31-year-old man who developed rhabodomyolysis following a long run. He had a prior history of exertional cramps and myoglobinuria. His maternal grandfather had similar symptoms. Transmission electron micrographs demonstrated continuity between the lamellae of the cylindrical spirals and native myofilaments. Whether these unusual structures confer a derangement in myofilament function is uncertain.

Public health experts have warned of a worrying increase in resistance to antiviral drugs that is making infections such as HIV and hepatitis B more difficult to manage. ![][1] HIV particles (yellow and pink) budding from the surface of a T4 lymphocyte cell (blue) in a coloured transmission electron micrograph Credit: DR STEVE PATTERSON / SPL Evidence from research that followed 4500 British patients infected with HIV indicates that after two years of standard treatment with a combination of three different classes of … [1]: /embed/graphic-1.gif

The cartilaginous fish probably evolved about the same time as or just before the bony fish some 300 MYA during the great growth burst of animal and vegetable life on this planet. Chondrichthyes have skeletons composed entirely of cartilage and movable lower jaws usually with teeth. They are divided into two subclasses

Cell Biology Open any cell biology textbook and you will find a transmission electron micrograph of a cross section through a cell nucleus. The dense staining of heterochromatin, which is largely inactive and highly condensed, will be clearly visible as dark patches, often lining the inner surface of the nuclear membrane. However, there will be periodic gaps in these heterochromatic territories at peripheral sites where the nuclear pore complexes (NPCs) are situated. NPCs are macromolecular structures that enable the transit of nucleic acids and proteins across the nuclear envelope. Although the existence of these NPC-associated heterochromatin-free regions has been known for over 50 years, how they are generated and what their function is have remained unknown. Krull et al. have discovered a role for the NPC-binding protein Tpr in establishing NPC-associated zones free of heterochromatin. In a cell culture model where heterochromatin condensation and heterochromatin exclusion zones around the NPCs could be induced vigorously, they found that depletion of Tpr resulted in dramatic nuclear reorganization as heterochromatin became evenly spread around the nuclear periphery and NPC-associated exclusion zones were lost. Keeping the NPC portals clear of heterochromatin might facilitate passage of the 1000 molecules that are transported through a single NPC per second in human cells. That a single protein can generate these exclusion zones is somewhat surprising and an important first step. EMBO J. 29 , 10.1038/emboj.2010.54 (2010).

The accurate measurement of kidney glomerular basement membrane (GBM) width from transmission electron micrographs provides vital information in the diagnosis of some kidney diseases. A novel and effective algorithm has been developed for the semi-automatic detection of the GBM by image analysis techniques. The method makes use of the gradual variation of the local features that are characteristic of the membrane. Starting from a seed point specified by the user, local features within a small window are computed to give a feature score. Feature scores for adjacent neighborhoods are also determined, and windows that satisfy a similarity criterion are linked to produce the centerline of the membrane. A region-growing process completes the segmentation procedure.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Fig 2. The diagnosis of thin basement membranes is made by electron microscopy. There is diffuse attenuation of the glomerular basement membrane, as illustrated here. In adults, basement membrane thickness less than 250 nm is indicative of thin basement membranes. However, processing and the age of the patient must be taken into consideration, because basement membranes normally increase with maturational growth. Thus, the diagnosis of thin basement membranes in children must be made only after comparison for normal standards in a given laboratory. The presence of thin basement membranes is characteristic of so-called benign familial hematuria, but can also be the only finding in early stages of Alport’s Syndrome, in female carriers of Alport’s Syndrome, and even at stages of established disease in some kindreds with otherwise typical X-linked Alport’s Syndrome. Thus, I prefer to use the term thin basement membrane lesion, rather than disease, because this morphologic finding does not specifically allow definite prognostication. (Transmission electron micrograph, original magnification 33,000).

Figure 1. An eight-year-old girl was found to have proteinuria and microscopic hematuria on a routine examination. A photomicrograph (Panel A) shows an enlarged, lobulated glomerulus with irregular thickened glomerular capillary walls, often with a double-contour appearance, so-called tram tracks (arrowheads); moderate mesangial expansion; and moderate hypercellularity (periodic acid–Schiff, ×20). A fluorescence photomicrograph (Panel B) discloses coarse and bulky granular deposits of C3 along the glomerular capillary wall and, to a lesser extent, in mesangial areas (×25). A transmission electron micrograph (Panel C) reveals large, subendothelial, electron-dense deposits (asterisks) and mesangial interposition (×4000). CL denotes capillary lumen, EN endothelial cell, . . .

This is the first edition of a multiauthored text on hemostasis and clinical disorders of blood clotting and thrombosis. The first third of the book is divided into three major sections: coagulation and fibrinolysis, platelets, and the vessel wall. Each chapter in these sections is an indepth discussion of a specific aspect of physiologic hemostasis and includes the molecular biology, biology, and biochemistry of clotting factors, platelets, and endothelial cells. The information is very detailed and could be used as a definitive reference on the structure and function of all important molecules and cells that support or inhibit hemostasis. The text is supported by excellent diagrams and tables. There are good-quality color plates of megakaryocytes but minimal scanning or transmission electron micrographs. One of the major deficits of this basic section of the book is the absence of an initial detailed overview of both primary and secondary hemostasis, including endothelial

Scanning electron and transmission electron micrographs of tissue biopsies from experimental third-degree burns treated topically with 96% oxygen for twenty-five days, without modifying the environment of the whole animal, revealed a marked promotion of collagen maturation. The O2-treated wounds showed a high ratio of collagen-ground substance; assembling of distinct fibers to form bundles with individual fibers of 1,360 +/- 95 A in diameter and an organized orientation; a highly aggregated rough endoplasmic reticulum of the fibroblasts, consisting of large cisternae and abundant ribosomes. The control burn wounds exposed to ambient air exhibited a low ratio of collagen-ground substance; a loose, rough endoplasmic reticulum; fiber diameter of 700 +/- 70 A, with haphazard orientation of the fibers; and a poor tendency to form bundles. These findings suggest that topical treatment of experimental deep burns with 96% O2 promoted collagen maturation and organization as well as collagen synthesis.

Shape of cells and extracellular channels in the rabbit cortical collecting ducts. Superficial cortical collecting ducts of rabbits were examined by scanning electron microscopy and by computer-assisted morphometric analysis of transmission electron micrographs. The epithelium contains two cell types, principal and intercalated, which have similar surface concentrations for apical and basal cell membranes and which can be modeled as simple cuboidal cells. The epithelium also contains two distinct and markedly different systems of extracellular channels. One system, the lateral intercellular channels, is comparable to the spaces between simple cuboidal cells but is modified by laterally projecting microvilli and ridges that produce a 1.8-fold magnification of the lateral cell surfaces. Those surfaces are nearly identical in the two cell types and constitute 38% of all cell membranes facing extracellular channels. The other channel system, the basal infolded channels, is well developed only in the basal 40% of principal cells and constitutes 62% of all channel-associated membrane. Its unique feature is an exponential increase in surface area, which is reminiscent of all channel-associated membranes in proximal nephron segments and which can be modeled as the interdigitation of cellular leaflets entirely within the boundaries of single cells. Forme des cellules et des canaux extracellulaires dans le canal collecteur cortical du lapin. Des canaux collecteurs corticaux superficiels de lapins ont ete etudies par microscopie electronique a balayage et par analyse morphometrique sur ordinateur d'images de microscopie electronique par transmission. L'epithelium contient deux types cellulaires, des cellules principales et des cellules intercalaires, qui ont les memes surfaces membranaires apicales et basales et peuvent etre consideres comme de simples cellules cuboides du point de vue des modeles. L'epithelium contient aussi deux systemes de canaux extracellulaires distincts et tres differents. L'un, celui des canaux intercellulaires lateraux, est comparable a l'espace entre des cellules cuboides simples modifie par des microvilli a projection laterale et des cretes qui produiscent une augmentation de 1,8 fois des surfaces laterales des cellules. Ces surfaces sont tres semblables dans les deux types cellulaires et constituent 38% de toutes les membranes cellulaires qui bordent les canaux extracellulaires. L'autre systeme, celui des canaux basaux invagines, n'est bien developpe que dans la portion basale des cellules principales et constitue 62% des membranes associees a des canaux. Son caractere principal est l'augmentation exponentielle de la surface qui rappelle l'aspect des membranes associees a des canaux dans le nephron proximal et qui peut etre modelise comme les interdigitations de feuillets cellulaires a l'interieur des limites de chaque cellule.

A 5-year-old Bulldog was examined for breeding soundness 6, 10 and 26 weeks after suffering from a posthitis, which extended caudally to include the scrotum. On first semen examination, Spermac-stained smears examined under the light microscope showed that 50 per cent of the spermatozoa had abnormal heads, and a further 20 per cent had other abnormalities. On second examination, the head abnormalities were reduced to 38 per cent, although the total abnormality count was 92 per cent. The various abnormalities noted with the light microscope were confirmed by the transmission electron micrographs, which revealed a variety of bizarre head abnormalities, diadem defects, acrosomal cysts and Dag defects. Between the second and third examinations the dog sired a litter of six pups, and on third examination had a normal spermiogram.

White pelicans were each given 100 mg of polychlorinated biphenyls (Aroclor 1254) per day for 10 weeks. After the treatment period, the bird's food supply was decreased 50% for 2 weeks. Measurements taken from transmission electron micrographs of the pelican's liver tissue revealed hepatocytes of the treated birds averaged 22% larger in cross-section area than those of controls. The number of vacuoles (lysosomes, microbodies) per hepatocyte was 22% greater. The number of mitochondria per hepatocyte was 25% greater while 25% fewer cristae per mitochondrion were present in treated as compared to control birds.

In recent years advances have been made in detailing the changes in both collagen and noncollagenous proteins caused by a variety of mutations leading to osteogenesis imperfecta. Much less, however, is known about the mineral phase in the affected bone. In this report, we measured the crystallinity of the apatite in bovine OI bone. Line broadening of the 002 reflection (which estimates changes in the long or c axis of the crystals) and of the 310 reflection (which estimates changes in the thickness of the crystals) both show large decreases (30 and 35% respectively). Transmission electron micrograph measurements indicate that these changes were most probably a result of smaller crystals. No decrease in the ash weight of the bone was observed.

A relatively large number of animal models of candidosis exist in which the efficacy of antifungal substances can be evaluated. These include models of candidosis of the skin, gastrointestinal tract, genital system, and internal organs in a variety of animal species. The efficacy of ketoconazole administered orally and topically was evaluated; when given orally in relatively low doses, ketoconazole was found to be efficacious in all of the experimental models used. Scanning and transmission electron micrographs of infected tissue demonstrated the rapidity with which Candida albicans was eradicated from the host after administration of ketoconazole.

Point-counting, a technique previously used with transmission electron micrographs, has been adapted for use with scanning electron micrographs. This bioassay technique enabled quantification of the relative proportions occupied by ciliated and non-ciliated cells in rat trachea and bronchus. Statistically significant decreases in the area of ciliated cells were detected in rats exposed to tobacco smoke for 10 days. In both control and smoke-exposed rats there were consistently higher areas of ciliated cells in the dorsal than ventral trachea.

• A 7-year-old child with a history of seizures, psychomotor regression, and progressive visual loss was found to have juvenile type neuronal ceroid lipofuscinosis on the basis of characteristic ophthalmoscopic and electroretinographic findings. Although transmission electron micrographs of two separate skin biopsy specimens were normal, peripheral blood lymphocytes were vacuolated and demonstrated, by ultrastructural examination, characteristic "fingerprint profiles" confirming the diagnosis. Peripheral blood lymphocytes from the patient's mother, who had an acquired seizure disorder, demonstrated vacuolated lymphocytes with membranous formations and osmophilic granular bodies, as revealed by electron microscopy. Examination of peripheral blood lymphocytes can be a sensitive diagnostic test in suspected neuronal ceroid lipofuscinosis and may be useful in identifying carriers or family members in the early clinical stages of the disease.

The external structure of the male gamete of Mytilicola intestinalis is studied under a scanning electron microscope and compared with transmission electron micrographs of thin sections corresponding to the different parts of same. The cell in question is long and filiform, showing, along a significant part of its length, two ridges or expansions helicoidally arranged and diametrically opposed. Four different parts or segments can be identified in this spermatozoon: segment A, characterized by its screw-like aspect; segment B, the longest, provided with well-developed helicoidal expansions; segment C, showing an uneven surface and lacking expansions; and segment D, with a smooth surface and decreasing diameter. The significance of this original structure in a spermatozoon, considered immobile until now, is discussed, stating different hypotheses with regard to the possible mobility of the cell just before fertilization takes place.

The embryogenesis of the tapeworm Cittotaenia variabilis from the oocyte to the oncosphere is followed using scanning electron microscopy (SEM) in conjunction with ethanol cryofracture. Transmission electron micrographs and histochemistry are used to corroborate the inferences drawn from the SEM studies. Evidence is given for oocyte granules, the uterine epithelium, and the outer envelope as sources of components for the outer capsule. The contributions and senescence of the inner envelope and its relationship to the embryophore are given.

The mechanical properties and ultrastructure of normal human tricuspid valve chordae tendineae were examined. Mechanical studies showed that these chordae exhibited less extensibility than normal mitral valve chordae of comparable size. The non-linear stress-strain curve of the tricuspid chordae, however, can be attributed to their microstructure. Under scanning electron microscopy these chordae were found to consist of fairly straight collagen bundles that were made up of networks of collagen fibrils. Transmission electron microscopical studies showed that the distribution of collagen fibril size was bimodal with an average fibril diameter of 441 A (S.E. = 2A) while the average fibril density was 198.4 (S.E. = 8.4) per 10(-8) cm2. These data data from the transmission electron micrographs were found to be different from those already reported for the mitral valve chordae. Thus, fine structural differences exist between chordae from both the mitral and tricuspid valves. These differences in fine structure could be due to the fact that these valves are under different in vivo mechanical stresses and they may account for the less extensible nature exhibited by the tricuspid chordae tendineae.

The determination of void volumes from transmission electron micrographs is an essential part of evaluating the void swelling in irradiated materials. Three commonly-used methods of determining the void volume are investigated. The apparent change in the volume of octahedral voids in f.c.c. metals with orientation and void truncation is calculated. The resulting error in void voluinc can be as great as 60% if the void geometry is not taken into account. The socalled matching area method is found to be least sensitive to orientation and truncation and leads to less than ± 10% error in void volume at orientations near [110]. This method is therefore the most suitable for routine void measurements.

The teeth of the adult plethodontid salamander, Plethodon cinereus, were examined by light and electron microscopy with emphasis on the ringlike zone of uncalcified dentin that divides the calcified portion of each tooth into a proximal pedestal and a distal apex. The uncalcified region displays radial asymmetry, forming an integral part of the posterior wall of the tooth but bulging into the pulp cavity anteriorly, thus forming a hingelike structure. All portions of the dentin, including the uncalcified region, are composed predominantly of collagenous fibers but lack elastin. In scanning electron micrographs of teeth from which the oral mucosa has been removed, the location of the anterior uncalcified hinge is marked externally by a notch-like articulation of the apex and pedestal. Sites of transition between calcified and uncalcified areas of the dentin show no special modifications in transmission electron micrographs, but collagenous fibers in calcified portions are associated with more electron-dense amorphous material than are those in the uncalcified region. Odontoblasts associated with the uncalcified region possess ultrastructural features closely resembling those of odontoblasts found in calcified areas. The uncalcified region seems to afford the teeth a certain degree of flexibility, and the asymmetry of the region appears to allow the teeth to flex only in a posterior direction, thus facilitating the entry of living prey but hindering its escape. The uncalcified region also seems to permit the apex of a tooth to break away from its pedestal without damage to underlying bone.

Altogether 100 specimens of 16 species of this highly diversified genus have been studied. Pollen morphology has been found useful in the grouping of the species, but of no use for distinguishing between species within the same group. The three earlier established pollen-types, the Crassiuscula-, Kilimandscharica- and Volkensii-types, have been confirmed. The inter- and intraspecific variation in the Crassiuscula-type, is mainly in sexine thickness, shape of bacula and processes. In the other two types, the variation is mainly in sexine pattern, shape and width of lirae. The three pollen-types are illustrated with scanning electron micrographs (SEMG) and transmission electron micrographs (TEMG).

Internal vascular ultrastructural detail of renal microcirculation observed by a combination of latex injection/corrosion/scanning electron microscopy techniques can be correlated with structures visible in transmission electron micrographs. Glomeruli of normal and hypertensive rats have been examined using both techniques. In the casts, indentations occur which are comparable in size, shape and frequency to nuclei of endothelial cells; and other irregular indentations may be correlated with the occurrence of platelet thrombi and endothelial cell proliferation. From these observations we conclude that ultrastructurally accurate casts of blood may be visualized by scanning electron microscopy. Such visualization offers much promise for the study of microcirculatory structures in states of disease and altered function.

We have used the freeze fracture and cytoplasmic maceration technique to study microsporogenesis inCatananche caerulea L. and here we present preliminary observations of the male germ unit (MGU)in situ. The technique has the advantage of enabling the complex structure of the MGU to be seen in a single fracture plane whereas previously this was only possible by the reconstruction of transmission electron micrographs of serial thin sections. The arrangement of the two generative cells and the vegetative nucleus closely resembles that described from other species includingPlumbago zeylanica.

The youngest reported case of laryngeal granular cell tumor is presented together with transmission electron micrographs of the tumor cells. Whereas subglottic involvement is unusual in adults, a review of the literature reveals that three of the seven youngest patients (including the present patient) with laryngeal granular cell lesions had a subglottic tumor immediately below the anterior commissure.

Photoelectron micrographs of gold-palladium coated mouse 3T3 cells and chick embryo fibroblasts are presented. Since the gold-palladium suppresses differences in work function, the cell morphology seen in these micrographs is due to relief contrast. The heights of comparable cells were measured from the parallax present in transmission electron micrograph stereo-pairs of cell surface replicas. The origin of relief contrast and the effect of cell surface relief on the working depth of field in photoelectron images of cells are discussed. The micrographs demonstrate that photoelectron microscopy is very sensitive to fine details of cell surface topography, and that the working depth of field is not a limiting factor in the imaging of well-spread tissue culture cells.

The conjunctiva plays an important role in external ocular physiology by contributing to maintenance of the tear film. Light and electron microscopical studies of the conjunctiva in Sjogren syndrome have been studied and changes such as stratification of the epithelium, elongation of the epithelial cells, widening of the intercellular spaces and reduction of the number of microvilli and number of goblet cells have been described(1,2).

Although the impact of electron microscopy on biomedical research is undeniable, diagnostic applications have only recently become well established. The science of electron optics led to the first practical electron microscopes in the 1930s and published papers describing the ultrastructure of biological specimens were almost commonplace by the 1950s (Peven and Gruhn 1985). Originally it was assumed that fastidious attention to fixation was imperative and that specimens which had been treated suboptimally were useless. It gradually became clear, however, that diagnostically useful information could be obtained from tissues that had first been routinely handled for light microscopy. The technique is now regarded as an indispensable adjunct to light microscopy for the interpretation of renal biopsies and the histogenetic diagnosis of tumours.

Facial recession defects were created on maxillary canine teeth of six Macaca irus monkeys and left untreated and exposed to oral fluids for 6 to 12 weeks. Notches were placed in the exposed root surfaces at the level of the free gingival margins. Following root planing with the addition of topical citric acid application on experimental surfaces, pedicle flaps were coronally positioned over the previously exposed roots. After euthanasia, block sections representing postsurgical time periods of 0, 3, 7, 14, 21, 28 and 42 days were secured and tissues were processed for histologic evaluation. All citric acid-treated surfaces exhibited new connective tissue attachment of pedicle flaps to previously exposed areas by 14 days with transmission electron micrographs confirming beginning cementum deposition. In contrast, controls demonstrated epithelial migration to, or apical to, reference notches. Although the total number of samples available for statistical comparison was small, a two-tailed t test for correlated samples showed citric acid application did not result in enhanced clinical root coverage, but did result in significantly greater amounts of new connective tissue attachment (P less than 0.05, df = 3). Pedicle flap healing against teeth with devital pulps was identical to that seen in teeth with vital pulps, while citric acid application to root-planed surfaces of vital teeth had no observable effect upon pulpal tissues.

Scanning electron microscopy was used to study prenatal muscle development in mouse fetuses ranging from 12 days to 18 days gestation. Some transmission electron micrographs were also used for comparison. At 12 days no myofibres were evident although at 13 days long fibres surrounded by many mononucleated cells could be seen. At 14 days bundles of primary myofibres were observed with new myofibres forming in crevices between adjacent fibres. At 16 days the primary myofibres had separated but smaller secondary myofibres could be seen forming along their surfaces. The myofibres were very compact at 18 days and often appeared fused but this was due to the basal lamina ensheathing clusters of primary myofibres with their secondaries. The scanning electron micrographs appeared to illustrate the theories of muscle development which have arisen out of the various studies employing sectioning techniques.

The areas of 2327 mast cell granules in transmission electron micrographs of sections of peritoneal mast cells from adult rats were measured by digitized planimetry. A histogram constructed using equivalent volumes calculated from the measured areas assuming approximation of the granules to spheres showed a periodic multimodal distribution in which the modes fell at volumes that were successively larger integral multiples of the volume at the first mode. Application of a moving-bin technique to the data confirmed the presence of the modes. We propose a mechanism of fusion of unit sized granules to account for the multimodal distribution. The presence of pear- and dumbbell-shaped granules in mast cells is consistent with this mechanism.

The migration of stratified squamous epithelium in organ cultures of rat palatal explants has been studied using scanning and transmission electron microscopy. The scanning microscope revealed plate-like folds at the margins, and microvilli on the bodies of cells. These structures were most highly developed on those cells nearest the leading edge of the sheet of cells and are interpreted as an index of cells that are migrating. The cells at the leading edge have broad flat pseudopodia in direct contact with the collagen bundles. A time lapse cinemicrographic study showed that the net forward movement of cells (nuclei) remote from the leading edge was at least as great as that at the leading edge immediately in front of them and the distance they travelled was greater than that of the leading edge. In transmission electron micrographs of these migrating epithelial cells from in vivo wounds, profiles that could correspond to the microvilli and plate-like folds could be found on the surface of the migrating cells. The results of this study suggest a simple model for the particular type of movement that occurs in stratified squamous epithelium in healing wounds where a mass of cells is produced that can both migrate into the wound and undergo stratification and cornification. A tracked vehicle shedding a broken track is used as an analogy of the model proposed.

Morphometric comparison of rabbit cortical connecting tubules and collecting ducts. Connecting tubule (CNT) segments of the rabbit distal nephron were examined by scanning electron microscopy and computer-assisted morphometric analysis of transmission electron micrographs. CNT were very similar to the cortical collecting ducts (CCD) described previously. The epithelium of both segments contains two cell types, both of which can be modeled as simple cuboidal cells, and two distinct systems of extracellular channels. The lateral intercellular channels are comparable to the spaces between simple cuboidal cells but are modified by short projecting microvilli which produce a modest increase in lateral cell surface area. The basal infolded channels are best developed in the connecting tubule cells of CNT and contribute 63% of all channel-associated membranes in CNT. Total membrane areas are similar in CNT and CCD. The two segments differ only in the degree of extracellular channel dilation and the distribution of infolded membrane relative to cell height in the connecting tubule and principal cells. The relatively minor morphometric differences between CNT and CCD do not correlate well with the marked difference in transtubular volume flow induced in the two segments by ADH and an osmotic gradient. Comparaison morphometrique des tubules connecteurs et des tubes collecteurs corticaux de lapin. Des segments de tubules connecteurs (CNT) de nephron distal de lapin ont ete examines par microscopie electronique a balayage, et par analyse morphometrique avec ordinateur de micrographies electroniques en transmission. Les CNT etaient tres semblables aux tubes collecteurs corticaux (CCD) decrits anterieurement. L'epithelium des deux segments contient deux types cellulaires, qui peuvent etre modelises comme des cellules cuboides simples et deux systemes distincts de canaux extracellulaires. Les canaux intercellulaires lateraux sont comparables aux espaces entre les cellules cuboides simples, mais sont modifies par les projections de courtes microvillosites qui produisent une augmentation moderee de la surface laterale cellulaire. Les canaux basaux contournes sont les plus developpes dans les cellules de tubules de connection des CNT et forment 63% de l'ensemble des membranes associees aux canaux des CNT. Les surfaces membranaires totales sont identiques dans les CNT et les CCD. Les deux segments different seulement par le degre de dilatation des canaux extracellulaires et par la distribution des membranes invaginees par rapport a la hauteur cellulaire dans le tubule de connection et les cellules principales. Les differences morphometriques relativement minimes entre CNT et CCD ne sont pas bien correlees avec les differences marquees dans le flux volumique transtubulaire induit dans ces deux segments par l'ADH et un gradient osmotique.