Millipore Filter Technique Research Articles

Urinary schistosomiasis in school children of a southern nigerian community 8 years after the provision of potable water.

Urinary schistosomiasis, one of the neglected tropical diseases, is a major infection of public health importance in Nigeria. Control measures include the provision of potable water as the main strategy, population-based chemotherapy and health education. The aim of this study was to determine the effect of the provision of potable water on the prevalence and intensity of infection with Schistosoma haematobium in Adim community, Cross River State, Nigeria. A cross-sectional survey was carried out among school and children aged 5-14 years in Adim community in Cross River State using the polyamide millipore filter technique and ova detection and count compared with the situation that obtained 8 years earlier before the provision of potable water. The prevalence and intensity of haematuria and proteinuria by reagent strips were also compared between the two eras. The prevalence of schistosomiasis was 14.5% compared to 51% in the prepotable water era (P = 0.001). The intensity of the infection was also significantly reduced between the two eras with 1.3% of the children having a severe intensity compared to 4.5% in the prepotable water era. The prevalence and intensity of S. haematobium have significantly reduced in this community though not yet eliminated. More boreholes need to be provided to make the water more accessible. This could be combined with other measures to eradicate S. haematobium from this community.

Circadian Changes in Feeding Activity and Diet of Hydropsyche saxonica (Trichoptera)

AbstractCircadian changes in feeding activity and diet of instar IV and V larvae of Hydropsyche saxonica were studied in the Vrbovecký brook (Czech Republic). The larvae were hand‐picked at 6‐hour intervals. The ratio maximum foregut diameter/head capsule width was used to determine gut fullness and the contents of larval foreguts were analyzed using a millipore filter technique. One‐way ANOVA revealed significant differences in gut fullness among instar V larvae collected at different times. Guts were fuller in the larvae collected at dusk and at dawn, indicating high crepuscular activity. No significant temporal differences in gut fullness were recorded for instar IV larvae. There were no significant differences in foregut contents among instar V or among instar IV larvae collected at different times. However, the difference between foregut contents of instar V and IV larvae was significant. Amorphous detritus was the most important food source for instars IV, whereas instars V fed mainly on animal food and cellular detritus. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

The Macular Hole

To delineate the light and electron microscopic features of tissue removed at the time of macular hole surgery. The ocular fluid specimens were concentrated using Millipore filters and stained with a modified Papanicolaou and the periodic acid-Schiff stains in 697 cases. In 92 cases, surgically isolated tissue was processed and examined by electron microscopy. The findings in the specimens studied by the Millipore filter technique included vitreous strands; cellular fragments in 108 cases (13.3%); fibrocellular fragments in 75 (9.2%); and fragments of internal limiting lamina (ILL) of the retina in 104 (12.8%). Findings in the 92 specimens with tissue studied by electron microscopy included native vitreous collagen in 48 cases (52.2%); new collagen in 6 (6.5%); native and new collagen in 1 (1.2%); ILL of the retina in 54 (58.7%); and a variety of cells in 22.5% of cases, including fibrocytes, myofibrocytes, fibrous astrocytes with and without myoblastic features, Mueller cells, retinal pigment epithelium with and without myoblastic features, and inflammatory cells. The organization of the tissue elements included a cellular layer along one surface of a layer of cortical vitreous in 18 cases, cortical vitreous along the inner surface of the ILL of the retina in 10, and cortical vitreous sandwiched between the ILL of the retina and a layer of cells in 9. Tangential traction induced by fluid movements affecting the cortical vitreous is a major factor in the pathogenesis of idiopathic macular holes. Cellular proliferation is a secondary change seen in 22.2% of cases.

The cAMP-binding proteins of Leishmania are not the regulatory subunits of cAMP-dependent protein kinase

The most commonly used method to determine the cAMP binding activity in cytosolic extracts of promastigotes of Leishmania spp. underestimated by approximately 11.5-fold the total amount of [ 3H]cAMP bound, when compared with results obtained by the modified Millipore filter technique. Three cAMP-binding proteins (BPI, BPII and BPIII) were partially purified and characterized. The native molecular masses of BPI, BPII and BPIII were estimated to be 105, 155 and 145 kDa, respectively. The binding of [ 3H]cAMP to these proteins was affected to different extents by several cAMP analogues. Antibodies directed against the types I and II regulatory subunits of PKA did not cross-react with the leishmanial extract. Photoaffinity labeling of the cytosolic extracts with 8-N 3-[ 32P]cAMP specifically labeled a band of M r 116 000 and a band of M r 80 000 partially saturable by cAMP. From these results, it is concluded that the leishmanial cAMP-binding proteins appear to belong to a different class distinct from the regulatory subunits of cAMP-dependent protein kinases.

Significance of Tissue Fragments in Voided Urine Specimens

To determine the diagnostic significance of tissue fragments in voided urine specimens. We reviewed all the voided urine specimens collected and processed by the Millipore filter technique (Bedford, Massachusetts, U.S.A.) at our institution between January 1, 1997, and December 31, 1998, and the corresponding biopsies obtained within 120 days after urine examination. The type and number of tissue fragments were correlated with the histologic diagnosis and clinical features; the results were compared to those from a recently published study. Of the 2,553 voided urine specimens examined, 174 (7%) had corresponding biopsies. Cell groups (tissue fragments) consisting of either flat sheets or three-dimensional structures were significantly more common (57%) (chi 2 P < .005) in urine specimens with biopsies revealing urothelial malignancies than in negative biopsies (6%). Three-dimensional groups were also statistically more common in cases with invasive transitional cell carcinoma. Proper identification of tissue fragments was highly significant and correlated with urothelial neoplastic changes. The results of the present investigation using the Millipore filter technique for voided urine cytology processing, differed from those of a recently published study that employed cytocentrifugation. Tissue fragments, to be differentiated from groups, clumps or clusters that often result from centrifugation and other concentration artifacts, were strongly associated with urothelial neoplasia, uncommonly with nonneoplastic disease processes affecting the urinary tract but always with urothelial disease.

A comparative cytologic study of body fluids and urine specimens processed by simple centrifuge and millipore filter techniques

Cyto-preparation of fluids is as important as cytodiagnosis in providing a good diagnostic service. A total of 134 fluid specimens consisting of 41 urine, 40 pleural fluid and 53 peritoneal fluid were processed by routine sediment smear and Millipore filter technique. The cytological diagnosis was categorized as suspicious, positive and negative for malignancy. Comparison of the two techniques was done with regards to recovery of cells, preservation of cell morphology, cell distribution and smear background. The differences were tested for significance by Chi-square tests. ‘P’ value less than 0.05 was considered significant. P value was significant for the parameters: celluiarity and distribution of cells for all three types of fluid. Significant difference was also observed for the parameter morphology of cells except for pleural fluid specimens. For urine specimens, morphology of cells was well preserved in 29 cases (70.7%) with Millipore filtration as compared to 12 cases (29.7%) with sediment smear technique. How ever p value was not significant (p=0.056). An additional 4 specimens (2.9%) with malignant cells were diagnosed by Millipore preparation. Although sediment smear technique is simple rapid, technical difficulties of Millipore filtration are clearly outweighed by the significant retrieval of well preserved, evenly distributed diagnostic cells. Therefore Millipore filtration can be a better option for cell concentration in fluid specimens as compared to the routine sediment smear technique.

Activation of palmitic acid by human spermatozoa.

Human spermatozoa were studied to determine if a long chain fatty acid, CoASH ligase (AMP) (E.C. 6.2.1.3), was present. Ligase activity was measured with a radioligand millipore filter technique and was readily detectable in spermatozoa or in the protein fraction extracted with Triton X-100, but was not present in seminal plasma. The assay was optimized for pH, protein concentration, and incubation time. Activity was dependent upon palmitic acid, ATP, coenzyme A, and a divalent cation. Sperm ligase appeared similar to the ligase characterized from other tissues by sharing a common pH optimum (approximately 8.0-8.4), and a preference for magnesium over manganese in the incubation media.

The cAMP receptor protein of Trypanosoma cruzi.

The widest used method to determine cAMP-binding activity in cell-free extracts (Gilman, A. G. (1970) Proc. Natl. Acad. Sci. U.S.A. 67, 305-312) underestimated by about 10-fold the total amount of [3H]cAMP bound by crude extracts of cultured forms of Trypanosoma cruzi (epimastigotes), when compared with the results obtained by the modified Millipore filter technique described by Doskeland and Ueland (Doskeland, S. O., and Ueland, P.M. (1977) Biochem. J. 165, 561-573). After column chromatography on DEAE-Sephacel, the cAMP-binding activity eluted as a single symmetrical peak at about 210 mM NaCl, totally separated from two peaks of cAMP-independent phosphotransferase activities which eluted, respectively, at 90 and 270 mM NaCl. These two protein kinases showed similar specificities for exogenous substrates, preferring in this order: protamine greater than casein greater than histone H2b. Photoaffinity labeling of cell-free extracts with 8-azido[32P]adenosine 3':5'-monophosphate and autoradiography following sodium dodecyl sulfate-polyacrylamide gel electrophoresis specifically labeled only one protein of Mr = 62,000. From these results it is concluded that T. cruzi epimastigotes possess one single cAMP-binding protein of monomeric Mr = 62,000, not associated with a phosphotransferase activity and probably very different in nature to known regulatory subunits of protein kinases, given the results obtained with the Millipore filtration technique.

Basophil degranulation induced by cigarette smoking in man.

There is some evidence that histamine could be a mediator of the immediate broncho-constriction that follows cigarette smoking. Since the chief reservoir of histamine in normal human blood is the basophil, we studied the acute effects of cigarette smoking on these cells. Capillary blood samples were obtained from 27 healthy young male smokers, before and 10 minutes after smoking. Basophils were collected and concentrated from these samples by a millipore membrane filter technique, stained with toluidine blue, and classified according to the staining characteristics and location of their cytoplasmic granules. This classification differentiated the "intact" from the "degranulated" basophils. A significant increase in degranulated cells and decrease in intact cells (p less than 0.001) was observed after smoking. Since histamine is present in the basophil granules, these findings suggest that cigarette smoking causes histamine release.

Initiation of protein synthesis in yeast: binding of Met-tRNAi.

Conditions for the binding of Met-tRNAi to 40 s ribosomal subunits and to proteins isolated out of the yeast ribosomal KCl wash were investigated. Sucrose density gradient experiments revealed that binding of Met-tRNAi to 40 s ribosomal subunits was catalyzed in a AUG and GTP dependent reaction. Binding of Met-tRNAi to proteins of the ribosomal KCl wash as assayed by the Millipore filter technique was found to be independent of AUG, GTP and 40 s ribosomal subunits. Additions of GTP yielded only slight stimulation, whereas Mg2+ caused dissociation of complexes. It was concluded that these reactions were most likely catalyzed by initiation factor eIF-2 although stimulation by GTP did not occur.

Kinetics of locomotion of human granulocytes in a double-filter system. Effect of activating plasma with zymosan and casein.

A new modification of Boyden's millipore filter technique is described in which leukocytes are sandwiched between two filters and allowed to migrate in two directions. This technique offers a better basis for comparison with mathematical models than does single filter methods. Using this technique, casein in low concentrations was leukokinetic in the absence of plasma, but did not show leukotactic activity unless plasma was present. Zymosan-activated plasma was leukokinetic and strongly leukotactic.

Leukemic Iris Infiltration

A 7-year-old boy with acute lymphocytic leukemia developed iris infiltration, blood-streaked hypopyon, and high intraocular pressure. A diagnostic anterior chamber paracentesis was performed, which provided a cytologic diagnosis. The aspirate was studied by both the millipore filter technique with Papanicolaou stain and a dried smear using the Wright's stain. Wright's stain provided more distinct cellular details. Irradiation of the anterior segment resulted in clearing of leukemic iris infiltration, hypopyon, and glaucoma.

Renal tubular mechanisms of organic solute transport

Renal tubular mechanisms of organic solute transport

Determination of polyadenylate-rich ribonucleic acid in the nucleus and in the cytoplasm of plasmacytoma cells.

A number of parameters affecting the adsorption of rRNA and poly(A)-containing RNA to Millipore filters were investigated separately. Binding of both types of RNA to the filter was dependent on the concentration of RNA, pH and Mg2+ concentration of the reaction mixture. Both types of RNA bound to the filter optimally at slightly acid pH values. The binding of poly(A)-containing RNA to the filter exhibited a broad pH-dependence compared with that of rRNA. The ratio of poly(A)-rich RNA/rRNA retained by the filter was maximal between pH7 and 8. The presence of 1 mM-EDTA or a high concentration of NaCl (over 0.5M) decreased the affinity of RNA for the filter. The amount of poly(A)-containing RNA in the nucleus and in the cytoplasm of a plasmacytoma cell line (MPC-11) labelled with [32P]Pi was determined by the Millipore-filter technique under conditions that minimized contamination by rRNA. These data were compared with the estimations made by oligo(dT)-cellulose chromatography. The results obtained by these two methods were in good agreement for RNA labelled for short periods (up to 2h). In long labelling and pulse-chase experiments, however, contamination of the filter by rRNA of increasing specific radioactivity in the cytoplasm gave an erroneous value for poly(A)-containing RNA by the Millipore-filter technique. Determinations made on the nuclear fraction by these two methods did not show significant variation in short- and long-term labelling experiments.

Growth and Development of the Cheese Skipper Under Sterile, Unsterile, and Sterile-Inoculated Conditions1

Experiments were designed to compare growth and development of Piophila casei (L.) under sterile, unsterile, and sterile-inoculated conditions. A millipore-filter modification of an egg-sterilization technique was used. In unsterile treatments, eggs were washed only in tap water. For the sterile-inoculated condition, eggs were sterilized and inoculated with 0.5 ml of a 5-h culture of Proteus mutgaris (VPI strain no. 3). Chicken embryos served as growth medium. Use of the millipore-filter technique eliminated the transfer of eggs from one chemical to another, and allowed continual checks of egg survival. The results indicate that the normal flora accompanying eggs has no beneficial influence on the growth and development of P. casei, and that limiting the number of bacteria present may be advantageous to the insect. P. vulgaris has very little influence on growth and development of the cheese skipper.

Glucose transport by trypsin-treated red blood cell ghosts

1. Glucose transport has been studied in preparations of human erythrocyte ghosts which have been treated with trypsin (10μg/ml for 30 min). [ 3H] d-Glucose uptake by this preparation has been measured using a Millipore filter technique, with [ 14C] l-glucose serving as a marker for non-specific glucose uptake. Membrane vesicles prepared from erythrocyte ghosts did not preferentially take up d-glucose without prior treatment with trypsin. 2. This trypsin-treated erythrocyte ghost preparation demonstrates many of the characteristics of glucose transport: (1) the d-isomer is both taken up and released more rapidly than the l-isomer; (2) countertransport of d-glucose can be demonstrated; (3) competitive inhibition of d-glucose uptake is observed with certain sugars; (4) known inhibitors of glucose uptake, phlorizin and N-ethylmaleimide, inhibit d-glucose uptake. 3. Using very low concentrations of trypsin (1 μg/ml), the onset of glucose transport has been correlated with the pattern of cleavage of membrane peptides (assessed by polyacrylamide gel electrophoresis in sodium dodecyl sulfate). The appearance of glucose transport is temporally associated with the hydrolysis of two major membrane peptides. Specific d-glucose uptake is not inhibited by extensive proteolysis (trypsin, 100 μg/ml) or selective elution of specific peptides (by manipulation of ionic strength).

Inadvertent weather modification and Los Angeles smog

The potential mechanisms for inadvertent weather modification by anthropogenic aerosols are reviewed briefly. Within this framework, limited measurements of cloud condensation nuclei and ice nuclei taken during the 1969 Pasadena experiment are discussed. The condensation nuclei observations were made with an MRI thermal diffusion counter and the ice nuclei were made using a Millipore filter technique. The results suggest that the cloud condensation nuclei counts are in the range of 10 3cm −3 at 0.5% water vapor supersaturation, and they increase during the day in rough correspondence with the second moment of the aerosol distribution. On the other hand, the ice nuclei counts are in the range of 200 m −3 at 18°C, and appear to decrease during the day. Such diurnal behavior may be related to the “poisoning” of otherwise active nuclei in the presence of organic material in the Los Angeles atmosphere.

4] Ion transport (H+, K+ Mg2+ exchange phenomena)

Publisher Summary This chapter outlines the experimental techniques used in measuring the ion transport processes. Ion transport, particularly of H + ions, is intimately involved with electron transport and the energy conversion system of chloroplasts. The chemical potentials of ion gradients could be the driving force for phosphorylation. The basic observations is that light-induced electron flow results in H + ion uptake into the grana membrane of chloroplasts, usually in exchange for K + and Mg 2+ ions. The efflux processes are variable in circumstances where the proton uptake is consistently observed to be fairly constant in rate and extent. The measurement techniques used for potassium, sodium, magnesium, and calcium transport are also described. Atomic absorption spectrophotometry is the most convenient method for measuring the concentrations of these cations, and typical measurements. Various methods to separate chloroplasts from the suspending medium are discussed, thereby allowing assays to be performed on the supernatant solution. The Millipore filter technique consists simply of passing the chloroplast suspension over a Millipore filter and thus separating the chloroplasts from the suspension. The concentrations of potassium and sodium ion can be measured with electrodes in a manner similar to the measurement of H + ion concentration.

Sugar transport in neurospora conidia: influence of pH and starvation.

Uptake of 14C-sorbose and 14C-3-O-methylglucose by ungerminated conidia of Neurospora crassa was measured by means of the millipore filter technique.

Sugar transport in neurospora crassa.

1 Uptake of [14C]sorbose and 3-O-[14C]methylglucose into ungerminated and germinated conidia as well as mycelia of Neurospora crassa was determined by means of the millipore filter technique. 2 The rate of uptake of both sugars is lower in glucose-germinated conidia than in ungerminated conidia (glucose-repression). In germinated conidia it increases upon their starvation in mineral salts solution (derepression), in ungerminated conidia it remains constant. 3 Both in ungerminated conidia and in starved, glucose-germinated conidia, the rate of uptake of both sugars is maximal at pH 4.75. This would suggest that the transport systems measured are identical. However, Km-measurements revealed two separate systems for sorbose uptake in the two different cell types (Km ungerminated: 3.5 mM, Km germinated and starved: 10 mM), and one single system for 3-O-methylglucose uptake (Km 0.03 mM).