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PubMed2002

Transitional cell metaplasia of the uterine cervix is related to human papillomavirus: molecular analysis in seven patients with cytohistologic correlation.

BACKGROUND: Transitional cell metaplasia of the uterine cervix is an under-recognized entity in cervical pathology. The underlying etiology and biologic significance remains uncertain. The thin-layer cytology findings and association with human papillomavirus (HPV) have not been studied thoroughly. METHODS: The authors retrospectively reviewed the clinical findings, thin-layer cytology and histologic features of pure transitional cell metaplasia of the uterine cervix occurring in seven perimenopausal or postmenopausal Chinese women at Pamela Youde Nethersole Eastern Hospital, Hong Kong, during the period from January, 1998 to April, 2001. Molecular techniques for HPV screening and genotyping using polymerase chain reaction and restriction fragment length polymorphism analysis were employed in the thin-layer cytology specimens and paraffin block material. RESULTS: In all seven patients, transitional cell metaplasia represented an incidental histologic finding. It occurred in the ectocervix, transformation zone, endocervix, or vagina. Histologically, it resembled urothelium of the urinary bladder and was comprised of multilayers of mitotically inactive, immature epithelial cells with vertically aligned oval nuclei, fine chromatin, indistinct nucleoli, and conspicuous longitudinal nuclear grooves. The superficial cells were oriented more horizontally and contained pale-staining cytoplasm similar to umbrella cells. Features consistent with transitional cell metaplasia were identified in two of seven preoperative thin-layer preparations. Cytologically, the affected parabasal cells recapitulated the features that were seen in histologic sections. In addition to the bland nuclear morphology and longitudinal nuclear grooves, the cell borders appeared distinct, and the appearance of a perinuclear cytoplasmic halo was common. Sometimes, the metaplastic cells assumed a spindle shape and appeared as cohesive, streaming cell clusters. Molecular study successfully demonstrated the presence of HPV in all seven patients, mostly in the liquid-based cytology samples. In general, the viral DNA load was relatively low; and, for samples in which HPV genotyping was feasible, HPV type 58 was the prevalent genotype. CONCLUSIONS: The current study demonstrates that transitional cell metaplasia of the uterine cervix is related to HPV. It also carries a distinctive cytologic appearance in thin-layer preparations. Based on the limited follow-up data from a small number of reported patients, transitional cell metaplasia seems to run an indolent clinical course. However, its peculiar association with HPV and its possible correlation, both morphologic and histogenetic, with cervical intraepithelial neoplasia need further investigation.

Aged↗
PubMed1987

Gene expression in adeno-associated virus vectors: the effects of chimeric mRNA structure, helper virus, and adenovirus VA1 RNA.

We used a recombinant plasmid containing an adeno-associated virus (AAV) genome to construct several vectors which express the gene for chloramphenicol acetyltransferase (CAT). We transfected four different AAV-CAT vectors into human 293 (adenovirus-transformed) cells and analyzed CAT activity. We show that, for vectors using the AAV p40 and p19 promoter, the chimeric AAV-CAT transcripts began from the correct 5' position but the basal level of CAT expression depended in part on the structure of the transcript. We also examined the effects of coinfection of the cells with the helper adenovirus or cotransfection with a plasmid which expressed the adenovirus translational control RNA, VA1 RNA. Cotransfection with plasmids containing the gene for VA1 RNA resulted in elevated levels of CAT activity. VA1 RNA stimulated translation of the chimeric mRNA. However, in two cases, the VA1 RNA apparently decreased the level of mRNA. These results suggest that in addition to its function in translation, VA1 RNA acts at a second site to alter cytoplasmic accumulation of some mRNAs. Infection with adenovirus increased CAT activity several-fold by increasing the cytoplasmic levels of the chimeric AAV-CAT transcript. When the CAT gene is inserted down stream of the AAV intron, adenovirus and not VA1 RNA alone increased CAT activity by promoting accumulation of a spliced transcript.

Adenoviruses, Human↗
PubMed2006

Calcium uptake and membrane trafficking in response to PTH or 25(OH)D3 in polarized intestinal epithelial cells.

Cell culture techniques providing retention of the polarized enterocyte morphology has allowed, for the first time, comparison of parathyroid hormone (PTH)- and 25-hydroxyvitamin D(3) [25(OH)D(3)]-induced (45)Ca uptake with membrane trafficking events discerned using confocal microscopy. Treatment of cells with 65 pM bPTH(1-34) promoted enhanced (45)Ca uptake between 1 and 10 min after peptide. The protein kinase A (PKA) antagonist, RpcAMP inhibited hormone-mediated uptake. At the microscopic level, cells labeled with the endocytic tracking dye FM1-43 revealed increased punctate staining 50-550s after hormone. Pretreatment of cells with RpcAMP abolished this pattern of staining. The calcium indicator dye fluo-3 AM revealed faint punctate labeling in controls, with increased bands of punctate labeling in the apical region of the cells after peptide hormone, and ultimately the basal region. Parallel studies conducted with the metabolite 25(OH)D(3) resulted in a slower stimulation of (45)Ca uptake 5-10 min after steroid, which was also inhibited by preincubation with RpcAMP. Cells labeled with FM1-43 and then treated with steroid showed no change in distribution of fluorescence during the 10 min incubation period. Confocal microscopy with fluo-3 revealed intense apical fluorescence--that after steroid --streamed to a perinuclear position, and ultimately the basal area. Uniformly diffuse staining, which would indicate cytoplasmic calcium transport, was observed only in controls. Membrane trafficking and compartmentalized calcium appear to be integral to agonist mediated cation transport.

Animals↗
PubMed1956

Observations on an ATP-sensitive protein system from the plasmodia of a myxomycete.

1. Extracts of the plasmodia of the myxomycete, Physarum polycephalum, exhibit reversible decreases in viscosity in response to the addition of ATP under appropriate conditions. The protoplasm material prepared by extraction with KCl solution can apparently exist in either a high or a low viscosity state. As prepared, it is in the low viscosity condition. Rapid and extensive increases in viscosity of the extract are brought about by addition of AMP, inorganic phosphate, or, under certain conditions, of ATP. Only after the high viscosity state has been attained does addition of appropriate quantities of ATP cause a reversible decrease in viscosity. 2. The active principle of crude plasmodial extracts may be concentrated by fractional precipitation with ammonium sulfate and is found in the fraction precipitated between 30 and 40 per cent saturation. This material possesses a higher viscosity than does the original crude extract and is apparently in the high viscosity state since the addition of ATP causes an immediate reversible decrease in viscosity. 3. The ATP-sensitive fraction of myxomycete plasmodia possesses a viscosity which is dependent upon its previous thermal treatment. Extracts incubated at 0 degrees for a period of a few hours increase greatly in viscosity when they are returned to 24.5 degrees . This increased viscosity is structural in nature, is destroyed by mechanical agitation of the solution, and may be reversibly destroyed by addition of ATP. 4. It is suggested that the ATP-responsive protein of myxomycete plasmodia may be related to sol-gel transformations which have been observed in intact plasmodia and may participate in the protoplasmic streaming of the intact organism. This suggestion is based upon the following facts: (a) the protoplasmic streaming of myxomycete plasmodia is increased by microinjection of ATP; (b) the gel portion of the cytoplasm at the site of the microinjection of ATP is extensively converted to the sol state. The changes in structure of the intact cytoplasm are thus similar in nature to the changes exhibited in response to ATP by the purified ATP-sensitive protein. 5. The ATP-sensitive protein of myxomycete plasmodia appears to undergo reversible aggregation to form a high viscosity state. The function of ATP is to break down the aggregates thus formed. Since a specific ATPase activity is associated with the purified material, added ATP is gradually destroyed and recovery of viscosity attends the spontaneous reconstitution of aggregates.

Adenosine Triphosphate↗
PubMed2005

Vulvar lipoleiomyoma in a dog.

A vulvar neoplasm from a 5-year-old female Siberian Husky dog was removed surgically and examined histologically. Macroscopically, the neoplasm was firm, white, and measured 6 x 4 x 3 cm. Microscopically, the neoplasm was expansile, nonencapsulated, and composed of lobules of mature adipocytes ad-mixed with streams and bundles of well-differentiated smooth muscle cells. Immunohistochemically, the neoplastic cells had strong diffuse cytoplasmic immunoreactivity for alpha-smooth muscle actin and desmin, and no immunoreactivity for cytokeratin or vimentin. On the basis of gross, histopathologic, and immunohistochemical findings, a diagnosis of lipoleiomyoma was made. This is, to the author's knowledge, the first report of canine vulvar lipoleiomyoma.

Animals↗
PubMed1999

SNARE membrane trafficking dynamics in vivo.

The ER/Golgi soluble NSF attachment protein receptor (SNARE) membrin, rsec22b, and rbet1 are enriched in approximately 1-micrometer cytoplasmic structures that lie very close to the ER. These appear to be ER exit sites since secretory cargo concentrates in and exits from these structures. rsec22b and rbet1 fused to fluorescent proteins are enriched at approximately 1-micrometer ER exit sites that remained more or less stationary, but periodically emitted streaks of fluorescence that traveled generally in the direction of the Golgi complex. These exit sites were reused and subsequent tubules or streams of vesicles followed similar trajectories. Fluorescent membrin- enriched approximately 1-micrometer peripheral structures were more mobile and appeared to translocate through the cytoplasm back and forth, between the periphery and the Golgi area. These mobile structures could serve to collect secretory cargo by fusing with ER-derived vesicles and ferrying the cargo to the Golgi. The post-Golgi SNAREs, syntaxin 6 and syntaxin 13, when fused to fluorescent proteins each displayed characteristic patterns of movement. However, syntaxin 13 was the only SNARE whose life cycle appeared to involve interactions with the plasma membrane. These studies reveal the in vivo spatiotemporal dynamics of SNARE proteins and provide new insight into their roles in membrane trafficking.

Animals↗
PubMed2000

Redistribution of Golgi stacks and other organelles during mitosis and cytokinesis in plant cells.

We have followed the redistribution of Golgi stacks during mitosis and cytokinesis in living tobacco BY-2 suspension culture cells by means of a green fluorescent protein-tagged soybean alpha-1,2 mannosidase, and correlated the findings to cytoskeletal rearrangements and to the redistribution of endoplasmic reticulum, mitochondria, and plastids. In preparation for cell division, when the general streaming of Golgi stacks stops, about one-third of the peripheral Golgi stacks redistributes to the perinuclear cytoplasm, the phragmosome, thereby reversing the ratio of interior to cortical Golgi from 2:3 to 3:2. During metaphase, approximately 20% of all Golgi stacks aggregate in the immediate vicinity of the mitotic spindle and a similar number becomes concentrated in an equatorial region under the plasma membrane. This latter localization, the "Golgi belt," accurately predicts the future site of cell division, and thus forms a novel marker for this region after the disassembly of the preprophase band. During telophase and cytokinesis, many Golgi stacks redistribute around the phragmoplast where the cell plate is formed. At the end of cytokinesis, the daughter cells have very similar Golgi stack densities. The sites of preferential Golgi stack localization are specific for this organelle and largely exclude mitochondria and plastids, although some mitochondria can approach the phragmoplast. This segregation of organelles is first observed in metaphase and persists until completion of cytokinesis. Maintenance of the distinct localizations does not depend on intact actin filaments or microtubules, although the mitotic spindle appears to play a major role in organizing the organelle distribution patterns. The redistribution of Golgi stacks during mitosis and cytokinesis is consistent with the hypothesis that Golgi stacks are repositioned to ensure equal partitioning between daughter cells as well as rapid cell plate assembly.

Cell Division↗
PubMed2000

WHIM syndrome, an autosomal dominant disorder: clinical, hematological, and molecular studies.

The acronym WHIM refers to Warts, Hypogammaglobulinemia, Infections, and Myelokathexis. The latter refers to the retention of white cells in the marrow, which becomes hypercellular. We have found approximately 20 examples of WHIM syndrome in the literature under various designations; the first examples are Zuelzer [1964] and Krill et al. [1964]. Chronic noncyclic neutropenia and hypercellular bone marrow represent defective release of marrow cells into the peripheral stream (myelokathexis). The hypermature neutrophils are bizarre in form. Condensed nuclei connected by long, stringy filaments and vacuolated cytoplasm suggest apoptosis. Fever or other stress increases the release of neutrophils. Hypogammaglobulinemia is marked and associated with recurrent upper respiratory infections (sinusitis, tonsillitis, otitis media, pneumonia). Patients have numerous warts, some venereal, with resultant cervical and vulval premalignant dysplasia. We report on a kindred of 6 affected individuals in 3 generations with autosomal dominant WHIM syndrome. The sex ratio among reported patients and in our kindred is 17 female to 8 male. Because there had been no male-to-male transmssion, search of the entire X-chromosome including the pseudoautosomal area was carried out and no linkage was found. Recently, the propositus has had an unaffected daughter, confirming our finding that the gene is not X-linked. A genome-wide search is being carried out.

Adolescent↗
PubMed1986

Cardiac hormones: morphology and biochemistry.

The heart contains, in addition to its myocardial working cells and the conductive system, a specialized endocrine part localized mainly in the atrial appendage which is predominantly made up by myoendocrine cells. The ultrastructural and immunocytochemical analysis of myoendocrine cells show a specialized secretory apparatus involved in the synthesis and secretion of cardiac hormones. These cardiac hormones are synthesized and processed in the myoendocrine cells as follows: a preprohormone is found in the rough endoplasmic reticulum, the prohormone cardiodilatin/gamma-atrial natriuretic polypeptide (CDD/ANP) is processed in the Golgi apparatus and stored in the secretory granules. The circulating peptide, cardiodilatin 99-126/alpha-ANP, is the C-terminus of this preprohormone which is released as the active circulating form into the blood stream.

Animals↗
PubMed1994

Molecular cloning of human E-cadherin suggests a novel subdivision of the cadherin superfamily.

The gene encoding full-length human E-cadherin has been cloned and sequenced from liver and colon cDNA libraries (GenBank Accession #L08599). The predicted molecular mass of the unglycosylated and unprocessed protein is 97,000. The human protein conserves most features of the classical cadherins. In its cytoplasmic domain, two approximately 30-35 aminoacid conserved sequence motifs are recognized. These cadherin homology domains have been termed "CH2" and "CH3", and are characteristic of the classical cadherins, but absent or divergent in the more distantly related cadherins such as desmosomal cadherin, T-cadherin, fat, and the human ret oncogene. Given these findings and the importance of cytoplasmic interactions to cadherin function, a subclassification of the cadherin superfamily based on cytoplasmic domain homologies is proposed. This subclassification provides a framework in future studies for understanding the distinct down-stream signaling cascades associated with each cadherin.

Base Sequence↗
PubMedDate not supplied

Histochemical and ultrastructural investigation on the cytotypes in the mouse Harderian gland.

The presence of melatonin and other biogenic indoleamines in the Harderian gland has been proposed by various authors. In the present work we would have investigated which of the cytotypes of the mouse Harderian gland might be involved in melatonin turnover. For this aim we employed the osmium tetroxide-zinc iodide (ZIO) histochemical technique that has been proposed useful to identify indole monoamines. Harderian glands of male, female and pregnant female mice were studied by light and transmission electron microscopy (TEM). Secretory type B cells were selectively stained by the ZIO-mixture, much more in female than male; type A cells were much more numerous than type B ones and never ZIO-positive. Ultrastructural examinations showed that type B cells contain numerous granules in the whole cytoplasm, in the perinuclear cisterna and around the cytoplasmic vacuoles and vesicles. Myoepithelial cells were sometimes found weakly ZIO-positive. Endothelial cells of capillary blood vessels presented ZIO-precipitates in the cytoplasm, as well as in the perinuclear cisterna. These data may suggest an uptake of melatonin from the blood stream and an involvement of type B secretory cells in melatonin catabolic turnover, or a "in situ" melatonin biosynthesis and endocrine secretion by the same B cells. The higher ZIO-positivity of type B cells in female than male may be related also to the influence of sexual steroid hormones, that characterizes the porphyrin pigment amount involved in melatonin oxidation.

Animals↗
PubMed1993

Brefeldin A effects on tobacco pollen tubes.

Pollen germination and pollen tube growth were clearly affected by the drug brefeldin A: both processes could be stopped completely. Notable thickening of the cell wall was not observed in non-growing pollen tubes, and plasma streaming remained vigorous in the presence of brefeldin A. Over time, the tip region became filled with a dense cytoplasm that lacked large organelles. Ultrastructural observation showed the rapid dissociation and disappearance of Golgi bodies. The concomitant appearance of vesicle-like structures attached to the endoplasmic reticulum (ER) suggests a fusion of the Golgi with the ER similar to that which happens in animal cells. Secretory vesicles disappeared from drug-treated tubes, and the tip region became filled with tubular ER. As the actions of the drug seemed to be reversible, brefeldin A may contribute substantially to research on Golgi dynamics and tip growth in pollen tubes.

Biological Transport↗
PubMed1983

Studies on the motility of the foraminifera. II. The dynamic microtubular cytoskeleton of the reticulopodial network of Allogromia laticollaris.

Lamellipodia have been induced to form within the reticulopodial networks of Allogromia laticollaris by being plated on positively charged substrata. Video-enhanced, polarized light, and differential interference contrast microscopy have demonstrated the presence of positively birefringent fibrils within these lamellipodia. The fibrils correspond to the microtubules and bundles of microtubules observed in whole-mount transmission electron micrographs of lamellipodia. Microtubular fibrils exhibit two types of movements within the lamellipodia: lateral and axial translocations. Lateral movements are often accompanied by reversible lateral associations between adjacent fibrils within a lamellipodium. This lateral association-dissociation of adjacent fibrils has been termed 'zipping' and 'unzipping'. Axial translocations are bidirectional. The axial movements of the microtubular fibrils can result in the extension of filopodia by pushing against the plasma membrane of the lamellipodia. Shortening, or complete withdrawal, of such filopodia is accomplished by the reversal of the direction of the axial movement. The bidirectional streaming characteristic of the reticulopodial networks also occurs within the lamellipodia. In these flattened regions the streaming is clearly seen to occur exclusively in association with the intracellular fibrils. Transport of both organelles and bulk hyaline cytoplasm occurs bidirectionally along the fibrils.

Animals↗
PubMed1977

Laser light-scattering analysis of protoplasmic streaming in the slime mold Physarum polycephalum.

Laser light scattering is shown to be an effective means of obtaining a rapid, objective assessment of dynamic changes in the intact plasmodium of the myxomycete Physarum polycephalum during bidirectional (shuttle) streaming. The motion of material in a 100 mum diameter region of a plasmodial vein was studied by following changes in the autocorrelation function of the fluctuations in the scattered light intensity. The autocorrelation function was recorded at 10 s intervals and analyzed to follow changes in the flow velocity of protoplasm associated with shuttle streaming. Rhythmic velocity changes and a "beating" pattern of velocity maxima were readily observed. In an attempt to locate the site of underlying structural changes in the vein responsible for the changing pattern of flow, the average scattered intensity was separated into components derived from moving and stationary scatterers. Periodic variations in the light intensity due to stationary scatterers are related to the streaming cycle and indicate the occurrence of important structural changes in the vein walls. Two possible interpretations of the data are offered; one involving gross dynamic changes in vein structure, the other involving the formation, contraction, or breakdown of fibrillar material in the vein wall during the streaming cycle.

Cytoplasm↗
PubMed1978

A fluid mechanical hypothesis for macromolecular transport in living cells: I.

A fluid mechanical process generating controllable steady streaming is introduced as a model for explanation of specific molecular transport processes in living cells. Intracellular organelles, attached to contractile cytoplasmic fibrils and executing simultaneous oscillations and volume pulsations, are envisioned as the driving mechanisms for this transport system.

Biological Transport↗
PubMed1998

Accumulation pattern of IgG antibodies and Fab fragments in transgenic Arabidopsis thaliana plants.

For the further optimization of antibody expression in plants, it is essential to determine the final accumulation sites of plant-made antibodies. Previously, we have shown that, upon secretion, IgG antibodies and Fab fragments can be detected in the intercellular spaces of leaf mesophyll cells of transgenic Arabidopsis thaliana plants. However, immunofluorescence microscopy showed that this is probably not their final accumulation site. In leaves, IgG and Fab fragments accumulate also at the interior side of the epidermal cell layers and in xylem vessels. These accumulation sites correspond with the leaf regions where water of the transpiration stream is entering a space impermeable to the proteins or where water is evaporating. In roots, plant-made Fab fragments accumulate in intercellular spaces of cortex cells, in the cytoplasm of pericycle and, to a lesser extent, endodermis cells, and in cells of the vascular cylinder. In other words, antibody accumulation occurs at the sites where water passes on its radial pathway towards and within the vascular bundle. Taken together, our results suggest that, upon secretion of plant-made antibodies or Fab fragments, a large proportion of these proteins are transported in the apoplast of A. thaliana, possibly by the water flow in the transpiration stream.

Animals↗