Tissue Factor Pathway Inhibitor (TFPI) is a potent inhibitor of the extrinsic coagulation system, synthesized in endothelial cells. Membrane bound TFPI has recently been shown to play an important role in the degradation of activated coagulation factors in the endothelium. Comparison of subcellular TFPI localization patterns and TFPI production between Human Umbilical Vein Endothelial Cells (HUVEC) and an immortalized cell line (ECV 304) are presented here, as are the essential protocol modifications that we used to obtain labeling results by both light- and electron microscopy. We show that ECV 304 cells are similar to HUVEC in that TFPI is present in the Golgi complex (fig. 1) as well as in the endocytic pathway of ECV cells. Additionally, they secrete higher levels of TFPI into the culture medium than HUVEC. A colocalization of anti-TFPI with endocytosed BSA-gold, as well as with accumulated DAMP, demonstrated the presence of TFPI in the endocytic pathway.

A debated and yet unanswered question, in regard to polarization and directed movement of phagocytic cells, concerns the distribution of chemoattractant receptors during cell locomotion1. We have therefore studied the instantaneous distribution of N-formyl-peptide receptors on living neutrophils. Using a fluorescent N-formyl-peptide receptor antagonist, tert-butyloxycarbonyl-Phe(D)-Leu-Phe(D)-Leu-Phe-OH (Boc-FLFLF), and a fluorescent receptor agonist, formyl-Nle-Leu-Phe-Nle-Tyr-Lys (fnLLFnLYK), the localization of the chemoattractant receptors could be followed during random migratio2. Neutrophils were adhered to plasma-coated coverslips. A Nomarski differential interference contrast (DIC)- image was taken, and rapidly followed by a fluorescence-image captured with a water-cooled, slow-scan CCD-camera. Then a second DIC-image was directly recorded to reveal the direction of cell movement.

Using fnLLFnLYK we observed that the distribution of N-formyl-peptide receptors was clearly heterogeneous as shown in figure. Fluorescence was concentrated mainly at the rear and front of elongated locomoting cells, leaving the cell body almost non-fluorescent.

Using microbes for the biological control of pests is progressing very rapidly. Because of the high specificity and none of toxicity to the vertebrates, they become the environmental biopesticides. The most commonly used entomopathogen is Bacillus bacteria, such as B. thuringiensis.Mass culturing of B. thuringiensisin different types of fermentor is experimenting in order to reach the highest yield of endospore and the crystalline endotoxin, the main virulent components for the pesticidal activity.

Bacillus thuringiensisproduces endospore and the parasporal inclusions, Hannay (1953) observed in bacterium B. thuringiensis a mature endospore and a prism-shaped crystal (parasporal crystal).’ The endospore and the endotoxin crystal vary during growth depending upon the availability of nutrient. Glucose concentration in medium has enormous effects on the production of parasporal crystal, B. thuringiensiscan not grow, nor produce parasporal crystal in low concentration of glucose medium. The formation time of the endotoxin crystal also differs in different subspecies.

The protozoan parasite Toxoplasma gondiiis an obligate intracellular parasite that exhibits gliding and twisting motility during cell locomotion and host cell invasion. By using molecular and genetic approaches it has been determined that actin and myosin are localized beneath the parasite plasma membrane and produce the force for motility and active penetration during host cell invasion. However, structural evidence for actin fibers beneath the plasma membrane is still missing. Recently Chavez et al. demonstrated actin-like filaments in isolated cytoskeletal complexes. Our aproach has been to remove the cell membrane with 0.15% Triton X-100 in cytoskeleton preserving buffer, followed by imaging with low voltage field emission SEM. As seen in Fig. I, we could demonstrate the subpellicle actin network in parasites invading a host cell (arrow). Fig. 2 shows a similar subsurface network of actin filaments in a parasite gliding on glass.

The geminiviruses are a group of plant DNA viruses characterized by having one or two copies of a single-stranded, circular DNA genome and frequent occurrence of geminate, quasi-isometric particles as observed by transmission electron microscopy. The Geminiviridaefamily is classified into three genera (Mastrevirus, Curtovirus and Begomovirus)based on the number of DNA components, the plant hosts, and the transmission vectors. Maize streak virus (MSV), the type member of the Mastrivirusgenus, is transmitted by the leafhopper and infects Gramineaespecies. Wheat dwarf virus, Digitaria streak virus, and Chloris striate mosaic virus (CSMV) are examples of other members of the Mastrivirusgenus. The Nigerian strain of MSV (MSV-N) contains one copy of a singlestranded, circular DNA molecule (2687 nucleotides). Two protein products, VI and V2, are coded by the MSV-N genome.2 V2 (244 amino acids) is the only coat protein found in virions.

Chilo iridescent virus (CIV), the type species of the genus Iridovirusin the family Iridoviridae,was first isolated from the rice stem borer, Chilo suppressalis,a member of Lepidoptera insect order. ‘2 CIV is being considered as a potential pest control agent because of its wide host range which includes leafhoppers and some arthropods. The virion (∼lxl09 daltons) encapsidates a 209 kbp, dsDNA genome within its fiber-covered, icosahedral shell. The virion is composed of about 26 structural proteins, two (P50 and P'50, 50kDa each) of which are the major capsid proteins. P50 migrates as a monomer in either a reducing or non-reducing SDS-PAGE gel and is exposed to the surface, whereas P'50 exists as a disulfide-bond, stabilized trimer in a non-reducing gel and is only partially exposed. Virions contain 9% lipid present as a lipid bilayer within the protein capsid.

Lyme disease is the most common arthropod-borne infection in the United States. Over 100,000 cases have been reported to date. The disease is a multisystem disorder with dermatologic, neurologic and rheumatologic manifestations. The causative agent, Borrelia burgdorferi1has been isolated from ticks, animals and humans from around the world and can generally be cultured in the laboratory using BSK-II medium.

While biologically significant concentrations of eukaryotic cell inhibitors such as aphidicolin, ara C, cis platinum, CPX, hydroxyurea, mimosine, nalidixic acid, trioxsalen and boromethyglycine showed little effect on the growth of Borrelia burgdorferiwhen added to BSK-II cultures, PPMP, a spingolipid analogue, showed immediate and profound inhibitory effects when monitored by dark-field microscopy, transmission electron microscopy (TEM), field emission scanning electron microscopy (SEM) and by optical density measurements at 600 mμ. PPMP (dl-thzreo-l-phenyl-2-palmitoylamino-3-morpholino-l-propanol) is known to inhibit the synthesis of spingomyelin in Chinese hamster ovary cells and to inhibit the synthesis of glucosylceramides in a large variety of mammalian cells.

Clofoctol [2-(2,4-dichlorobenzyl)-4-(tetramethyl-l,l,3,3-butyl) phenol] is a synthetic antibacterial compound with activity against both Gram-positive1 and Gram-negative2 microorganisms. Although the specific mechanism of Clofoctol action has not been fully elucidated, it is reported to alter the permeability of the cytoplasmic membrane in Bacillus subtilis, and is used clinically to treat upper respiratory tract infections in humans. Staphylococcus aureus is a major human Grampositive pathogen that causes a variety of human diseases ranging from localized skin suppuration and food poisoning to life threatening presentations such as septicemia and endocarditis. Several clinical isolates of S. aureus have recently been identified that are resistant to all currently available antibacterial therapies. Consequently, the identification of new antimicrobial targets in this organism is of paramount importance. The purpose of this study was to investigate the in vitro effects of Clofoctol on S. aureus.

Ultrastructural examination of S. aureus revealed a population of actively dividing cells.

Ticks harbor several different genera of endosymbiotic bacteria. These obligate intracellular bacteria, most of which appear to be nonpathogenic for the tick, persist in nature by being transmitted transovarially from generation to generation. Those in the genus Rickettsiabelong to the spotted fever group (SFG) of rickettsia which includes both mammalian pathogenic and nonpathogenic species. The species that cause spotted fevers in humans, e.g. Rickettsia rickettsii, are well characterized but those not known to cause disease remain poorly understood. Transmission electron microscopy on SFG rickettsia cultured in tick cell cultures offers a powerful way to examine dynamic host parasite interactions in these apparently nonpathogenic SFG species.

We have successfully isolated two unknown, nonpathogenic rickettsia strains in tick cell lines. T2 was isolated from an Ixodes ricinus tick collected in the English Garden in Munich, Germany and is propagated in an Ixodes scapularis cell line, ISE6.

A current review (1) lists 21 cyanophages of coccoid and filamentous heterocystic and non-heterocystic blue-green algae (BGA). The capsid diameters of these viruses range from 50-90 nm, and none have been previously reported for Microcoleus,a sheath-producing, filamentous, surface colonizing BGA (Fig. 1), of the order Oscillatoriales, and class Cyanophyceae (= Cyanobacteria). From a freshwater culture of Microcoleussp. we report here a putative cyanophage with a side-to-side hexagonal capsid diameter of 140 nm, based on measurements from thin sections of algal filaments prepared for transmission electron microscopy (TEM).

An earlier report (2) documented the ultrastructure of mucilage secretion, and its role in sheath, trichome and filament formation in an isolate of the BGA Microcoleus sp. grown in soil-water medium. Now we report large cyanophage-like particles in a majority of cells making up the trichomes. These putative hexagonal viral capsids (Figs. 2-5) are mainly clustered in the center or to one side of the nucleoplasm.

Whipple's disease is a rare systemic disorder with the intestinal tract being the major site of predilection. The characteristic histologic features are the infiltration of large numbers of macrophages, which have a clear or vacuolated cytoplasm. In his original documentation of “a hitherto underscribed disease”, Whipple interpreted the vacuo lation to be due to deposits of fat and fatty acids and gave the name “interstinal lipodystrophy” to the pathology. In this report, Whipple did describe the presence of rod shaped organisms in Levaditi (reduced silver) stained preparations, but, it was not until a half century later, that the definitive presence of intracellular organisms was demonstrated by means of transmission electron microscopy. Further investigations showed that the organism is a Gram positive actinomycete, which has been designated as Tropheryma whippelii.

We report the case of a 72 year old woman, who was admitted with the chief complaints of abdominal cramps and diarrhea.

During April-July 1998, an increase in fatal cases of neurologic disease in young children occurred in Taiwan, with at least 55 fatalities reported. Concurrently, an outbreak of hand, foot, and mouth disease (HFMD) was also occurring. In fatal cases, the acute illness was characterized by fever, or rash, or mouth ulcers, followed by a rapid cardiopulmonary failure; death frequently occurred within 24 hours of hospitalization. Approximately three-fourths of the fatalities were in children less than 3 years of age. We report here the findings from autopsy specimens from two of the fatal cases of encephalomyelitis.

In Case 1, a 9-year-old female, H&E sections of central neurologic system (CNS) tissue showed perivascular infiltrate, areas of inflammation, necrosis, and neuronal degeneration. Immunohistochemical (IHC) staining was positive when using a monoclonal antibody for enterovirus 71 (EV71), a picornavirus associated with HFMD.

Acute lung injury is defined as a syndrome of inflammation resulting in increased capillary-alveolar permeability that is associated with a constellation of clinical, radiological and physiological abnormalities. Adult respiratory distress syndrome (ARDS), relatively common in the intensive care, is a more specific, severe form of ALI, with diverse causes. Diffuse alveolar damage is the pathognomonic feature of the syndrome. Under the pathophysiologic conditions of increasing capillary membrane permeability, large macromolecules can gain access to the interstitium, resulting in pulmonary interstitial edema, and from there enter the alveolar space in severe cases. Detecting the distribution of macromolecules in lung tissue, therefore, constitutes evidence of the injury. Traditional pathologic examination of biopsy/autopsy materials is the only route to provide pathologic evidence of the capillary-alveolar membrane damage induced lung injury. Although morphometric analyses are more laborious, they provide qualitative assessment of morphological changes that is an important aspect of acute lung injury, see Fig.l.

Cyclosporin-A(CyA) is a very potent immunosuppressive agent which is widely used in transplantations and autoimmune diseases. The aim of this study was to investigate (i) the vascular changes after long term and low dose CyA treatment, (ii)if Cremophor-EL(the vehicle in the intravenous form of CyA) is responsible from these changes, and (iii) the structural effect of combined therapy with prednisolone on light and electrone microscope level.

Twenty-four female Sprague-Dawley rats were divided into four groups: First group was control. The other three group had daily intraperitoneal injection of 4mg/kg/day CyA for 2.5 months. Second group had oral, third group had intravenous form of this drug while the fourth group had intravenous form with 1 mg/kg/day prednisolone. Biopsy specimens from renal cortex were embedded in paraffin and Araldite for light and electron microscopic examinations.

Light microscopic changes were quite similar in all three experimental groups and confined to arterioles and small arteries: Endothelial cells protruded into the lumen,even seperating from the intimal layer; while some of them were undergoing pyknosis.

Centrosome abnormalities and abnormal mitotic formations have been shown in human breast cancer tissue and in LNCaP and DU145 prostate cancer cells in culture. Here we report on abnormal centrosome and centriole organization in the transgenic adenocarcinoma mouse prostate (TRAMP) model and on the implications for abnormal cell divisions, genomic instability, and apoptosis. Centrosomes are microtubule organizing centers which assemble bipolar spindles in normal cells. In cancer, centrosomes cause the formation of mono-, tri-, and multipolar mitoses which will separate chromosomes unequally during cell division.

We investigated the occurence of abnormal mitoses in TRAMP tissue in different stages of cancer progression using transmission electron microscopy (TEM). Advanced stages of prostate cancer are characterized by multiple abnormal mitoses ranging from tripolar to unusual multipolar formations. In addition, apoptotic bodies are abundant which may indicate that multipolar mitoses will lead to cell death or apoptosis.

Barban and chlorpropham are common carbamate herbicides that disrupt mitosis by destabilizing plant microtubules. Tubulins, protein subunits of microtubules, in plant and animal cells are highly conserved through evolution. Plant and animal cells have been shown to possess similar microtubule structural proteins, microtubule binding proteins, and organizational proteins. These similarities suggest that herbicides targeting plant microtubules might also affect animal microtubules. Previous tubulin immunofluorescence microscopic studies of HeLa cells, a human cervical cancer cell line, have shown that barban is strongly cytoskeletotoxic and chlorpropham is weakly cytoskeletotoxic. Both barban and chlorpropham have been shown to disrupt mitosis and disorganize spindle apparatus formation in numerous types of mammalian cancer cells.

This investigation was undertaken to examine the effect of barban and chlorpropham on MRC-5 cells, a normal human fibroblast cell line, as well as on HeLa cells. A monoclonal antibody to α-tubulin, a microtubule specific protein, was used to probe the formation of spindle apparatuses in dividing cells.

Canine hepatozoonosis, an emerging tick-transmitted protozoal disease of dogs in the United States, was first recognized in Texas in 1978. Since 1978, the geographic distribution of the disease has expanded to include Louisiana, Alabama, Georgia, and Oklahoma. The expansion of hepatozoonosis maybe associated with spread of the tick vector, Amblyomma maculatumThe causative agent of North American hepatozoonosis was initially thought to be a particularly virulent strain of Hepatozoon canis,the parasite that causes hepatozoonosis in the Old World. However, because of notable differences between the disease and the morphologic features of asexual and sexual stages of the parasites in the USA and the Old World, the organism responsible for canine hepatozoonosis in North America was designated a new species, Hepatozoon americanumThe clinical course of canine hepatozoonosis in the USA is chronic, progressive, and generally fatal. The disease manifests with intermittent fever, gait abnormalities, marked lethargy, weight loss, muscle wasting, and pain.

Ultrastructural examination is sometimes necessary for diagnosis of surgical pathology material. Not uncommonly, tissue is not fixed in 3% glutaraldehyde prior to realizing that electron microscopy would be valuable or even necessary to render a diagnosis. It is well known that formalin can be an adequate fixative for ultrastructural evaluation of tissue. Increasingly, non-formalin based fixatives have become more popular with routine surgical pathology practice. Prefer™, a glyoxal-based fixative, has become a popular substitute for formalin in many institutions. We are not aware of any study that has compared ultrastructural morphology of tissue fixed in formalin to tissue fixed in a glyoxal-based fixative.

To address this question, we took sections of fresh tissue from three different tumors (metastatic melanoma involving a lymph node, squamous cell carcinoma of the lung, and mixed papillary serous and clear cell carcinoma of the ovary) and fixed a portion of each in 3% glutaraldehyde, 10% neutral buffered formalin, and Prefer™.

Primary cardiac tumors of any type in infancy and childhood are rare, with a prevalence of 0.03%reported in autopsy surveys carried out at children's hospitals. Within the pediatric population,the most common primary tumor involving the heart is rhabdomyoma. These tumors may bedivided into 3 groups: 1) arising in tuberous sclerosis; 2) arising sporadically; or 3) arising in congenital heart disease. Many cardiac rhabdomyomas are asymptomatic and regress early in life without clinically untoward effects. Only a small proportion of these tumors come to the attention of the pediatrician and pathologist when there is obstruction of blood flow, a murmur related to subaortic stenosis, or arrhythmias. Rhabdomyomas may be detected prenatally during ultrasound examination, with one case being diagnosed at 22 weeks gestation. Although it is possible to subdivide the tumors into 3 groups, the association of this entity with tuberous sclerosis is very strong with at least 60 to 85% of children with rhabdomyomas having tuberous sclerosis.

Two forms of muscular alterations have been described in alcoholic patients, one acute, the so called Hypokalemic alcoholic Myopathy; focal or diffuse pain, swelling, tenderness and weakness of skeletal muscle are the main clinical features, and the chronic one with proximal muscle weakness wich progresses slowly in a period of weeks or months Ultrastructurally myofibril disorganization and necrosis where described.

In this work we present a systematic study of skeletal muscle alterations in four alcoholic patients who attended the Department of Internal Medicine at Caracas University Hospital . The patients were males, ages between 56 and 62 years old, and presented chronic alcoholism with muscle weakness with a more distal distribution and polymyalgia. Biopsies were taken from quadriceps femorismuscle with a percutaneous neddle and processed for routine transmission electron microscopy.

Muscle fibers showed different degrees of atrophy with myofibril disorganization (Fig.l) and disappearence (Fig.2). Myonuclei were hyperchromatic and intermyofibrilar spaces were widened and exhibited abundant lipid droplets.