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PubMed1990

Monofilament nylon filters for preventing dracunculiasis: Durability and copepod retention after long term field use in Pakistan.

Filtration of drinking water to remove the cyclopoid copepod intermediate hosts of guinea worm. Dracunculus medinensis, is one of the primary intervention strategies for preventing dracunculiasis. In early 1987, monofilament nylon filters with 200 microns pore size were distributed to households in selected guinea worm-infected villages in Pakistan. The filters proved popular with the villagers, although reports of "loss of filters" could diminish the community-wide effectiveness of this control measure. After 12 to 15 months of usage a sample of these filters was collected and examined for damage or impairment which would decrease their use or their capacity to retain potentially infective copepods. Although all naupliar stages and early copepodids (Stages CI-II) passed through these used filters, the larger copepodids including adults (Stages CIII-VI) were retained despite small tears in the fabric. This field trial showed that after 12 to 15 months of regular use, monofilament nylon filters of 200 microns pore size remained effective in removing copepodid stages capable of supporting development of D. medinensis larvae. Considering the ease of use, popularity and effective filtration of potentially infective copepods following prolonged field use, we recommend that monofilament filters be considered in any program of guinea worm elimination.

Animals↗

PubMed1978

Immobilized-enzyme nylon-tube reactors for routine determination of urea and citrulline in serum.

A continuous-flow clinical analyzer for the routine estimation of urea is described that makes use of an immobilized-enzyme nylon-tube reactor as part of a flow-through system (a Technicon AutoAnalyzer I). Results of blood-urea analyses by use of the immobilized urease are compared with determinations made with the diacetyl monoxime method and the urease solution method. Clinical trials carried out routinely with the immobilized enzyme nylon tube reactor give reliable and reproducible results with high precision and low cost. The reactors are stable to intermittent or continued use for at least four months or for 2000 tests. A method is described in which differential colorimetry is used for determining citrulline in blood and which makes use of the immobilized urease, albeit indirectly.

Autoanalysis↗

PubMed1983

[Passive enhancement of allogeneic rat kidney transplants with antibodies against nylon-adhering splenic lymphocytes].

Male BD IX rats were intraperitoneally immunized with 6.35 X 10(6) nylon adherent spleen lymphocytes from male Sprague-Dawley rats (SD). The inbred strains used are different from each other at their major histocompatibility complex. Sensitized animals were exsanguinated 2, 4, 8 and 12 days after the primary injection. After the secondary injection on day 14 the animals were exsanguinated on day 21. The BD IX recipients of (BD IX X SD) F1 renal allograft were intravenously injected with 1 ml of the antisera immediately after completion of the transplant. Significant prolongation of survival time was already obtained with the 8-day-serum pool. The absorption of antiserum with packed SD red blood cells did not affect its enhancing activity. In vitro testing of antisera by 51Cr-release assay showed the highest titer of complement depending cytotoxicity 8 days after immunization. Whilst the cytotoxic activity against nonadherent spleen cells was completely lost after twice absorption with SD erythrocytes, the cytotoxic activity against adherent spleen cells was only slightly reduced. Thus it is likely that enhancing activity of alloantiserum is attributed to anti-Ia or anti-B-cell antibodies. These antibodies were detectable 4 to 8 days after immunization with low dose nylon adherent spleen cells.

Animals↗

PubMed1984

Enhanced production of human gamma-interferon in nylon column-fractionated cell cultures.

The production of human gamma-interferon (HuIFN-gamma) in unfractionated and nylon wool column-fractionated leukocyte cell cultures stimulated with PMA and PHA was investigated. Production was studied with normal and reduced autologous serum protein levels in 96-hr spinner cultures. A 10- to 15-fold enhancement of production and a 50-fold increase in specific activity of crude HuIFN-gamma was demonstrated in nylon column-fractionated/reduced serum cell cultures. Kinetic analysis revealed a production rate maximum within 6 hr of induction in unprocessed cell cultures, whereas production occurred at an essentially constant rate for 48 hr in fractionated cell cultures.

Blood Proteins↗

PubMed1980

Use of primary cultures of adult rat hepatocytes on collagen gel-nylon mesh to evaluate carcinogen-induced unscheduled DNA synthesis.

The procarcinogen, 2-acetylaminofluorene, the direct-acting carcinogen, methyl methanesulfonate, and two other hepatocarcinogens, thioacetamide and urethan, were tested for their ability to elicit unscheduled DNA synthesis in adult rat hepatocytes maintained in primary culture on collagen gel-nylon mesh. The carcinogens, dissolved in dimethyl sulfoxide were added to 6-hr or to 28-hr cultures along with [methyl-3H]thymidine (1 muCi/ml medium) in the presence of 10 mM hydroxyurea. Twelve hr later, the hepatocytes were harvested from the cultures with collagenase, and their DNA was purified on CsCl isopyknic gradients. Unscheduled DNA synthesis was measured as the increase in [methyl-3H]thymidine radioactivity incorporated per microgram DNA of the carcinogen-treated cultures as compared with that of control cultures. Both 2-acetylaminofluorene and methyl methanesulfonate demonstrated a concentration-dependent stimulation of unscheduled DNA synthesis in the 6-hr hepatocyte cultures. However, the response of the 28-hr cultures to these two carcinogens was absent unless the hepatocytes were preincubated for 22 hr in culture medium supplemented with 10(-5) M dexamethasone and 10(-6) M glucagon or in a more complete hormone-supplemented medium. Thioacetamide and urethan, on the other hand, failed to elicit a concentration-dependent unscheduled DNA synthesis under these conditions. The results obtained with this culture system are similar to those of other short-term tests for chemical carcinogenicity and support the potential use of the collagen gel-nylon mesh-hepatocyte primary culture as an in vitro screen for chemical carcinogens. Furthermore, this study suggests the importance of specific hormones in maintaining the capability for repair of DNA damage produced by carcinogenic and mutagenic chemicals in cultured hepatocytes.

2-Acetylaminofluorene↗

PubMed1982

A comparison of a disposable skin stapler and nylon sutures for wound closure.

A disposable skin stapler (Proximate; Ethicon) was compared with conventional nylon sutures in respect of time taken for wound closure, cosmetic result and ease of application and removal. It was found that a time saving of 80% is possible with the stapling device, and that the cosmetic result with staples is as good as if not better than that with nylon sutures. A certain amount of experience and practice facilitates the use of the stapler.

Humans↗

PubMed1980

Single- and coupled-enzyme nylon-tube reactors for plasma glucose determination with glucose oxidase and aldehyde dehydrogenase.

We describe routine methods for determining glucose in plasma with use of aldehyde dehydrogenase or glucose oxidase-aldehyde dehydrogenase immobilized in a nylon tube that is integrated into a continuous-flow system. Although the coupled-enzyme nylon-tube reactors require the presence of a third enzyme, catalase, in solution, the kinetics are not so complicated as to preclude reliable routine determination of glucose at very low cost. Precision is good, and results correlate well with those by the method involving glucose oxidase in solution. More than 3000 tests may be carried out with one reactor. The immobilized enzymes are stable for several months at 4 degrees C when not in use.

Aldehyde Dehydrogenase↗

PubMed1997

A study of combined filtration and adsorption on nylon-based dye-affinity membranes: separation of recombinant L-alanine dehydrogenase from crude fermentation broth.

Dextran, hydroxyethylcellulose (HEC), and poly(vinyl alcohol) PVA were covalently linked to bisoxirane-activated nylon membranes. Cibacron Blue F3G-A was immobilized on to these membranes to yield a dye-affinity membrane. The hydrodynamic permeability of affinity membranes was reduced to approximately 50% of that of the original Nylon membrane due to extension of polymer coils into flow-through pores. Adsorption of pre-purified human serum albumin (HSA) and malate dehydrogenase (MDH) displayed highest maximum binding capacities on HEC-coated dye-ligand-affinity membranes, ranging from (163 micrograms/cm2 for HSA to 316 micrograms/cm2 for MDH. The protein recovery of HSA was 100% on dextran-coated membranes compared with 70% on PVA-coated membranes, whereas almost 100% recovery was found for MDH, independent of the polymer. Application of crude supernatant from recombinant Escherichia coli yielded purification factors of 7.4, 8.9 and 11.2 for recombinant alanine dehydrogenase from Mycobacterium tuberculosis for HEC-, dextran- and PVA-coated membranes respectively. Dynamic capacities decreased remarkably to approximately 3 micrograms/cm2 due to co-adsorption of host proteins. The presence of cell debris caused only a slight decrease of purification factors, but a dramatic decrease of the permeability of affinity membranes due to development of a particle layer in front of the membranes. Although enzyme recoveries were up to 90% using cell-free supernatant, more than 50% of the product was lost due to polarization, concentration and rejection at particle layers when using crude homogenates. In order to further improve this integrated downstream process, sophisticated membrane techniques are required by which the formation of a filter cake is circumvented. Further refinement of polymer-coated membranes would not help one to avoid this problem.

Alanine Dehydrogenase↗

PubMed2000

Hydrolysis of glucosinolates using nylon-immobilized myrosinase to produce pure bioactive molecules.

Bioactive compounds were produced from natural glucosinolates, secondary plant metabolites, using myrosinase (thioglucoside glucohydrolase EC 3.2.3.1) isolated from ripe seeds of Sinapis alba. The enzyme was immobilized on granular nylon 6.6 with the crosslinking technique. Immobilized myrosinase displayed extraordinary operational and storage stability. Using a small thermostatted continuous packed-bed bioreactor, the enzyme activity was unchanged after 15 days of continuous use at 37 degrees C and after >1 year of storage at room temperature. The bioreactor was particularly efficient in producing pure isothiocyanates, but it was less efficient for pure nitrile production.

Bioreactors↗

PubMed2000

Epidemiologic investigation of respiratory morbidity at a nylon flock plant.

BACKGROUND: A cluster of biopsy-confirmed interstitial lung disease among workers at a nylon flock plant led to a request for National Institute for Occupational Safety and Health investigators to conduct a health hazard evaluation. METHODS: Part of the overall evaluation, reported here, involved a cross-sectional medical survey of current employees. The survey consisted of a questionnaire, spirometry and diffusing capacity testing, and chest radiograph. RESULTS: Workers assigned to production and maintenance jobs reported frequent eye and throat irritation, respiratory symptoms, and systemic symptoms (i.e., generalized aches and fevers). Most reported improvement when away from work. Frequent respiratory/systemic symptom prevalence was significantly associated with departmental category, with days and hours worked per week, and with working on a flocking range. Compared to asymptomatic workers, symptomatic workers had similar mean ratios of forced expiratory volume in one second to forced vital capacity, but lower mean percent of predicted values for both forced vital capacity and diffusing capacity. All acceptable chest radiographs were classified as category 0 for small opacities. CONCLUSIONS: Findings of this study, along with those from studies reported elsewhere, implicate occupational exposure to flock-associated dust as a significant respiratory health hazard at this plant.

Adult↗

PubMed1991

Controlled trial of polyglycolic acid versus catgut and nylon for appendicectomy wound closure.

Six hundred and fifty patients undergoing appendicectomy were included in a prospective randomized controlled trial. At operation patients were allocated to control (chromic catgut ligatures and muscle closure, nylon skin closure) or study (polyglycolic acid ligatures and muscle and skin closure) groups. Wounds were examined by an independent observer daily in hospital and 1 month after operation. Wound infection was defined as discharge of serous or purulent material, or a grossly inflamed wound without discharging pus, or any evidence of intra-abdominal sepsis. Of the 650 patients (335 men, 315 women, age 5-80 years, median 18 years), 615 have completed follow-up. Groups were well matched for age, sex, degree of sepsis at operation, histological diagnosis and surgeon. Infection was significantly reduced in the study (polyglycolic acid) group (12.0 per cent) compared with the control (chromic catgut/nylon) group (21.2 per cent) (chi 2 = 9.3, P = 0.002). Infection was significantly reduced in the polyglycolic acid group regardless of whether the appendix was inflamed or normal. These results indicate that suture material can influence the incidence of wound infection and that this is less frequent when polyglycolic acid sutures are used.

Adolescent↗

PubMed1975

Separation of antigen-specific lymphocytes. A new general method of releasing cells bound to nylon mesh.

Inserting a disulfide bridge between nylon and hapten or antigen allows the release of fiber bound cells by cleaving the disulfide bond with 10(-4) M 2-mercaptoethanol at 4 degrees C. Four to 12-fold enrichments in specific precursor cells could be obtained. The method is compared with the thermal release previously used. The T and B cell content of the specific fraction was determined. It is suggested that the low enrichment in plaque-forming cells of the hapten-specific fraction found after stimulation with antigen in vitro might be due to the fact that there is also enrichment for suppressor cells in the specific fraction.

Animals↗

PubMed1993

Electrotransfer of fixed phosphoproteins from pieces of dried polyacrylamide gel to small disks of nitrocellulose, nylon or polyvinylidene difluoride.

A simple method for the transfer of 32P-labeled proteins from dried polyacrylamide gels to small disks of nitrocellulose, nylon or polyvinylidene difluoride (PVDF) is described. Gel pieces containing the desired phosphoprotein are rehydrated in buffer containing sodium dodecyl sulfate (SDS) and sealed in agarose in a glass tube over a supporting gel of polyacrylamide. Protein is transferred upwards through a discontinuous density gradient of SDS-buffer and methanol to a disk of membrane sealed to the mouth of the tube with dialysis membrane. The method allows the concentration of a phosphoprotein present in several gel pieces to a single disk of immobilized membrane. Recovery of phosphoprotein was at least as good as obtained with conventional electroblotting. Application of the method to the analysis of the phosphoamino acid content of the astrocyte marker, glial fibrillary acidic protein, is described.

Amino Acids↗

PubMed1990

Relationship of the diameter and tensile strength of nylon sutures to the USP specification and the effect of preconditioning.

Nylon monofilament sutures were tested in a straight pull as well as a conventional knot pull tensile test. In each test, sutures were evaluated following storage under prevailing atmospheric conditions or saturation in whole human blood. Blood saturation decreased the ultimate tensile strength by as much as 20%. The present investigation of sutures that were stored under prevailing atmospheric conditions substantiated the proposal previously made for polypropylene monofilaments--that 60% of the ultimate tensile strength could be established as a fundamental USP criterion for Class I monofilament sutures.

Humans↗

PubMed1996

Effects of released products from platelets on neutrophilic adhesion to endothelial cells and nylon fibers.

In this study, the effects of platelet release products (PRPr), ATP, and ADP on the adhesion of human neutrophils to human umbilical vein endothelial cells (HUVEC) and nylon fibers (NF) are described and the implications of various adhesion molecules are considered. Adhesion of neutrophils to HUVEC and NF was increased by PRPr, ATP, and ADP, while their adhesion-increasing actions were cancelled or considerably repressed by apyrase treatment. When anti-CD11a or anti-CD11b was added to neutrophils with PRPr, ATP, or ADP, the adhesion-increasing action was cancelled or considerably repressed. On the other hand, anti-ICAM-1 and anti-CD35 had no significant effects on this action. The above results indicated that platelets, through ATP and ADP in PRPr, increased the adhesion of neutrophils to endothelial cells and foreign bodies. Although it was suggested that the adhesion-increasing action was at least partially based on CD11a and CD11b, ICAM-1 and CD35 had no part in the enhancement of the adhesion.

Adenosine Diphosphate↗

PubMed2003

Site-specific methylene blue delivery to pilosebaceous structures using highly porous nylon microspheres: an experimental evaluation.

PURPOSE: This study aimed to evaluate the penetration of methylene blue (MB)-loaded microspheres into pilosebaceous structures of rats. MATERIALS AND METHODS: MB was incorporated into 5 microm highly porous nylon microspheres. The microspheres were dispersed into fluid silicone. Male hairless rats were used to evaluate the penetration of MB into hair follicles. After formulation application, MB diffusion was induced and skin biopsies were realized immediately, 2 and 26 hours after MB loaded microspheres application. MB fluorescence was observed with a microscope expanded for fluorescence microscopy. RESULTS: Position of microspheres and MB diffusion was dependent on delay between microspheres application and harvest. Inside the skin, MB was seen exclusively in the hair follicle and the sebaceous glands. MB diffusion varied from 160+/-50 microm (2 hours after application) to 410+/-70 microm (26 hours after application). MB was also found in the sebaceous glands. DISCUSSION: This study confirms that 5 micro m microspheres are optimally deposited deep within the pilosebaceous structure. In agreement with the literature, when microspheres are topically applied on the skin, they penetrate via a "lipid-rich channel" coating the hair follicles. MB is exclusively distributed in the hair follicles and their accessories. CONCLUSION: This report presents evidence of MB pilosebaceous delivery through the use of microsphere formulation. This is obtained thanks to topical enhancement via the follicular route. This drug delivery system aims to transport MB into the pilosebaceous unit specifically and deeply. Various other applications could derive from this work. For example, such a method might be used to increase the therapeutic index of drugs directed at hair sebaceous gland disorders. Laser treatment of acne or laser hair removal could also benefit of this technique.

Animals↗

PubMed1994

Analysis of microsatellite DNA using a non-radioactive method: blotting from polyacrylamide gel to nylon membrane using a gel dryer with subsequent hybridization to digoxigenin-labelled (dCdA)8 oligonucleotide probes.

A non-radioactive method for the analysis of microsatellite DNA polymorphisms (mainly (CA)n-repeats) is described. Variation in length of (CA)n and (GT)n blocks was demonstrated directly by amplification of DNA from within and immediately flanking the repeat blocks using the polymerase chain reaction. The amplified DNA was resolved on a denaturing polyacrylamide gel, transferred to a nylon membrane using a gel dryer, and subsequently hybridized with digoxigenin-labelled (dCdA)8 oligonucleotide probes. This method enables easy and rapid analysis of polymorphic microsatellite DNA.

Acrylic Resins↗

PubMed1989

A comparison between three brands of 10.0 nylon sutures.

10.0 nylon sutures from three different manufacturers were compared on the basis of the scanning electron microscopic aspect, the maximum tensile strength of the thread and the maximum tensile strength of the knot (single throw). Scanning electron microscopy revealed identical surface characteristics and identical diameters (approximately 30 micrometers) for all threads. Threads which had been pulled on became wavy and showed markedly thinned and flattened segments. Maximum tensile strength was measured by a simple device, which is described. The maximum tensile strength of the thread varied considerably between the three brands (from 31.3 gr, S.D. 2.0 gr, to 46.2 gr, S.D. 3.7 gr.) The maximum tensile strength of the knot (single throw) was approximately the same for all three (ranging from 25.9 gr, S.D. 4.1 gr to 28.2 gr, S.D. 2.6 gr).

Microscopy, Electron, Scanning↗