Filter Paper Sample Research Articles

Prospective study of thyroid function in the first year of life in infants with Down syndrome.

Current American Academy of Pediatrics (AAP) Guidelines recommend monitoring thyroid function in infants with Down syndrome (DS) at birth, 6 and 12months, and annually thereafter. This study aimed to determine whether these guidelines are optimal for early diagnosis and treatment of (subclinical) hypothyroidism. Enrolled infants with DS less than age 7months, born at ≥ 30weeks gestation to monitor thyroid function test (TFT). A filter paper (FP) blood sample was analyzed for TSH and total T4 at ages 2 and 4weeks and monthly thereafter until 12months. Subjects with abnormal FP sample and confirmatory serum TFT for hypothyroidism promptly started treatment. Subjects with thyroid dysfunction identified had thyroid antibodies measured at diagnosis and 12months. Descriptive statistics determined average time to diagnosis of abnormal TFT. Sixteen (30%) of 54 subjects were diagnosed with a thyroid disorder, the majority with subclinical hypothyroidism (SH) and 1 with hyperthyroidism. Diagnosis occurred in 6 (11%), 9 (17%), and 12 (22.2%) infants in the first 30, 60, and 90days of life (DOL), respectively. Eight infants had an abnormal NBS and half were diagnosed with a thyroid disorder by DOL 8 and the remainder prior to 4months. Among subjects with a normal NBS, four were diagnosed at a mean of 104days and three at a mean of 101days prior to the 6-month and 12-month routine screens, respectively. Conclusion: Based on current AAP guidelines, thyroid disorder diagnosis would have been delayed in nearly 20% of the subjects. An additional TFT screen at 1 and 3months can lead to earlier diagnosis and treatment. What is Known: • Current American Academy of Pediatrics (AAP) Guidelines recommend thyroid function tests (TFT) in infants with Down syndrome (DS) at birth and 6 and 12 months. • Peer- reviewed retrospective studies report an increased incidence of hypothyroidism in infants with DS undetected by the newborn screen (NBS) and prior to 6 months. What is New: • This prospective study monitored TFT in infants with DS at age 2 weeks and monthly throughout the first year of life. • The findings in this study support additional TFT screens at 1 and 3 months in infants with DS.

Torrefied paper as a packaging material and subsequently as a bioethanol substrate: Synergy of torrefaction and alkaline treatment for increased utility

The sequential combination of torrefaction and alkaline treatment is one possible design strategy for a circular economy in which torrefied cellulosic paper with enhanced wet strength is repeatedly used as a packaging material, then hydrolyzed downstream for bioethanol production after alkaline treatment. The wet-tensile strength of cellulose filter paper increased by 1533%, 2233%, 1567%, and 557% after torrefaction for 40 mins at 200 °C, 220 °C, 240 °C and 260 °C, respectively. Glucose yield decreased with increase in torrefaction severity but after treating torrefied filter samples with alkaline (NaOH) solution, glucose yield increased. For instance, the glucose yield of raw filter paper was 955 mg/g of substrate whereas it was 690 mg/g of substrate for the same filter paper sample torrefied at 200 °C. The glucose yield increased to 808 and 933 mg/g of substrate with 1% and 10% alkaline treatment, respectively.

Detection of Antibodies Against Toxoplasma gondii in Filter Paper-Dried Blood Dot Spots Compared with Serum in Pigs and Assessment of Variation Associated with Packed Cell Volume.

The aim of this study was to assess the agreement between anti-Toxoplasma gondii IgG antibody detection in serum and filter paper (FP) blood spots using the indirect immunofluorescence antibody assay (IFA) and to evaluate the potential impact of the packed cell volume (PCV) on antibody detection in FPs. A pair of a serum and an FP sample was collected from 96 sows at various farms in Greece, with previously identified high seropositivity and/or risk factors associated with high seropositivity against T. gondii. The PCV value was determined using the microhematocrit method. IFA was used for the detection of antibodies against T. gondii. T. gondii-specific antibodies were detected in 45.8% serum samples and 41.6% FP samples showing almost perfect agreement. Detection in FP samples presented high sensitivity (87.1-92.8%) and excellent specificity (100%) when compared with detection in serum, regardless of the PCV values. The findings of this study support the reliability of FPs for the evaluation of the serological status of swine against T. gondii. FPs could be a good alternative sample type compared with serum for large-scale epidemiological studies.

Fabrication of super-hydrophobic filter paper via mixed wax phase separation for efficient oil/water separation

Despite previous efforts, the fabrication of superhydrophobic substrate via an environment friendly and easy approach remains a great challenge. In this study, a low cost, simple, and green procedure was developed to prepare a superhydrophobic paper surface that is acceptable for the papermaking industry. First, a wax mixture (beeswax & carnauba wax) was emulsified and coated on the filter paper surface. Then, the coated paper was annealed at different temperatures. The further heat-treatment-rendered wax-coated paper hydrophobic or superhydrophobic because submicrometer or micrometer wax structures were present on the paper surface. The water contact angle of the annealed filter paper sample reached 151.5° at 60 °C, and the sliding angle was under 10°. Further, the relationship between surface composition and the hydrophobic properties of the coated paper samples was discussed. The obtained paper samples showed great potential in water/oil separation, as they had an efficiency over 99%. This work proposed a new simple and mild approach to fabricate superhydrophobic filter papers and explored the hydrophobicity and water/oil separation properties.

Evaluation of hemoglobin A1c measurement from filter paper using high-performance liquid chromatography and immunoturbidimetric assay

Glycated hemoglobin (HbA1c) measurement from whole blood (WB) samples is inconvenient for epidemic surveillance and self-monitoring of glycemic level. We evaluated HbA1c measurement from WB blotted on filter paper (FP), which can be easily transported to central laboratories, with high-performance liquid chromatography (HPLC) and immunoturbidimetric assay (ITA). WB was applied to Whatman filter paper. By using HPLC and WB samples as reference methods, these FP samples were evaluated on HPLC and ITA. Inter- and intra-assay variation, WB vs. FP agreement and sample stability at 20–25 °C and −70 °C were assessed by statistical analysis. Results showed that the coefficient of variation (CV, %) of FP samples for HPLC and ITA were 0.44–1.02% and 1.47–2.72%, respectively (intra-assay); 2.13–3.56% and 3.21–4.82%, respectively (inter-assay). The correlation of WB HPLC with FP analyzed using HPLC and ITA are both significant (p < 0.001). Sample stability showed that FP method up to 5 days at 20–25 °C and 5 weeks at −70 °C is accurate and reproducible. In conclusion, FP samples analyzed by HPLC and ITA can both provide an alternative to WB for HbA1c measurement, supporting the use of FP method in epidemic surveillance and healthcare units.

Filter paper-assisted cell transfer (FaCT) technique: A novel cell-sampling technique for intraoperative diagnosis of central nervous system tumors.

Intraoperative diagnosis of central nervous system (CNS) tumors provides critical guidance to surgeons in the determination of surgical resection margins and treatment. The techniques and preparations used for the intraoperative diagnosis of CNS tumors include frozen sectioning and cytologic methods (squash smear and touch imprint). Cytologic specimens, which do not have freezing artifacts, are important as an adjuvant tool to frozen sections. However, if the amount of submitted tissue samples is limited, then it is difficult to prepare both frozen sections and squash smears or touch imprint specimens from a single sample at the same time. Therefore, the objective of this study was to derive cells directly from filter paper on which tumor samples are placed. The authors established the filter paper-assisted cell transfer (FaCT) smear technique, in which tumor cells are transferred onto a glass slide directly from the filter paper sample spot after the biopsy is removed. Cell yields and diagnostic accuracy of the FaCT smears were assessed in 40 CNS tumors. FaCT smears had ample cell numbers and well preserved cell morphology sufficient for cytologic diagnosis, even if the submitted tissues were minimal. The overall diagnostic concordance rates between frozen sections and FaCT smears were 90% and 87.5%, respectively (no significant differences). When combining FaCT smears with frozen sections, the diagnostic concordance rate rose to 92.5%. The current results suggest that the FaCT smear technique is a simple and effective processing method that has significant value for intraoperative diagnosis of CNS tumors. Cancer Cytopathol 2017;125:277-282. © 2016 American Cancer Society.

Integration of diagnosis and treatment of sleeping sickness in primary healthcare facilities in the Democratic Republic of the Congo.

Control of human African trypanosomiasis (HAT) in the Democratic Republic of Congo (DRC) has always been a vertical programme, although attempts at integration in general health services were made in recent years. Now that HAT prevalence is declining, the integration question becomes even more crucial. We studied the level of attainment of integration of HAT case detection and management in primary care centres in two high-prevalence districts in the province of Bandundu, DRC. We visited all 43 first-line health centres of Mushie and Kwamouth districts, conducted structured interviews and inspected facilities using a standardised checklist. We focused on: availability of well trained staff - besides HAT, we also tested for knowledge on tuberculosis; availability of equipment, consumables and supplies; and utilisation of the services. All health centres were operating but most were poorly equipped, and attendance rates were very low. We observed a median of 14 outpatient consultations per facility (IQR 8-21) in the week prior to our visit, that is two patients per day. The staff had good knowledge on presenting symptoms, diagnosis and treatment of both HAT and tuberculosis. Nine centres were accredited by the national programme as HAT diagnosis and treatment centres, but the most sensitive diagnostic confirmation test, the mini-anion exchange centrifugation technique (mAECT), was not present in any. Although all nine were performing the CATT screening test, only two had the required cold chain in working order. In these high-prevalence districts in DRC, staff is well-acquainted with HAT but lack the tools required for an adequate diagnostic procedure. Attendance rates of these primary care centres are extremely low, making timely recognition of a resurgence of HAT unlikely in the current state of affairs.

BLOOD COLLECTED ON FILTER PAPER FOR WILDLIFE SEROLOGY: EVALUATING STORAGE AND TEMPERATURE CHALLENGES OF FIELD COLLECTIONS

Filter-paper (FP) blood sampling can facilitate wildlife research and expand disease surveillance. Previous work indicated that Nobuto FP samples from caribou and reindeer (Rangifer tarandus subspecies) had comparable sensitivity and specificity to serum samples (≥ 80% for both) in competitive enzyme-linked immunosorbent assays (cELISAs) for Brucella spp., Neospora caninum, and West Nile virus. The same sensitivity and specificity criteria were met in indirect ELISAs for Brucella spp., bovine herpesvirus type 1 (BHV-1), parainfluenza virus type 3 (PI-3), and bovine respiratory syncytial virus (BRSV), with adjusted FP thresholds used for PI-3 and BRSV. Comparable sensitivity and specificity values to serum were also observed for FP in virus neutralization (VN) assays for bovine viral diarrhea virus types I and II; however, reduced sensitivity is a potential limitation of FP samples in protocols that require undiluted serum (i.e., VN and N. caninum cELISA). We evaluated the performance of FP samples from reindeer and caribou in these nine assays after simulating potential challenges of high-latitude field collections: 1) different durations of storage and 2) different processing/storage regimes involving freezing or drying. Sample pairs (serum and FP) were collected from reindeer and caribou populations in 2007-10 and were tested in duplicate. Comparable performance to serum was defined as sensitivity and specificity ≥ 80%. In the storage experiments, FP performance was determined after 2 mo of storage dry at room temperature, and after two longer periods (variable depending on assay; up to 2 yr). After 1 yr, compared to frozen serum stored for the same period, sensitivity was ≥ 88% for all but two assays (68% BHV-1; 75% PI-3), and specificity remained >90%. A limited trial evaluated the effect of freezing FP samples as opposed to drying them for storage. There were no observed detrimental effects of freezing on FP sample performance, but rigorous investigation is warranted.

PCR diagnosis of visceral leishmaniasis in an endemic region, Mymensingh district, Bangladesh

Detection of Leishmania parasites in a clinical sample is necessary to confirm a suspected case of leishmaniasis. We compared the sensitivity of internal transcribed spacer 1-PCR (ITS 1-PCR) assay for parasite diagnosis with that of microscopic detection in clinical samples from kala-azar (KA) or post-kala-azar dermal leishmaniasis (PKDL) suspects in Mymensingh. Of 39 specimens collected from 35 KA and four PKDL suspects, 26 were positive by microscopic examination of smears from bone marrow and skin exudates; 38 specimens spotted on filter paper and 27 of the 28 Giemsa-stained slides tested by PCR proved positive by ITS1-PCR.

Newborn screening

The aim of newborn screening is to detect newborns with serious, treatable disorders so as to facilitate appropriate interventions to avoid or ameliorate adverse outcomes. Mass biochemical testing of newborn babies was pioneered in the 1960s with the introduction of screening for phenylketonuria, a rare inborn error of metabolism, tested by using a dried blood spot sample. The next disorder introduced into screening programs was congenital hypothyroidism and a few more much rarer disorders were gradually included. Two recent advances have greatly changed the pace: modification of tandem mass spectrometry and DNA extraction and analysis from newborn screening dried blood spot. These two technologies make the future possibilities of newborn screening seem almost unlimited. Newborn screening tests are usually carried out on a dried blood spot sample, for which there are special analytical considerations. Dried blood spot calibrators and controls, prepared on the same lot number of filter paper, are needed. Methods have a co-efficient of variation of about 10% due to the increased variability of a dried filter paper sample compared with other biochemical samples. The haematocrit is an additional variable not able to be measured. Also of importance is obtaining a balance between the sensitivity and specificity of each assay. Fixing cut-off points for action needs consideration of what is an acceptable percentage of the population to recall for further testing. Few assays are 100% discriminatory. Programs in Australasia currently screen for at least 30 disorders. Detection of these requires not only the assay of a primary marker but often determination of a ratio of that marker with another, or possibly an alternative assay, for example a DNA mutation. The most important disorders screened for are described briefly: phenylketonuria, primary congenital hypothyroidism, cystic fibrosis, the galactosaemias, medium-chain acyl-CoA dehydrogenase deficiency, glutaryl-CoA dehydrogenase deficiency and congenital adrenal hyperplasia, together with several other disorders detectable by tandem mass spectrometry. Newborn screening deals with rare disorders and benefit cannot be shown easily without very large pilot studies. There have been randomised controlled trials of screening for cystic fibrosis, and now several studies are beginning to establish the benefit of tandem mass spectrometry screening for disorders of fatty acid and amino acid metabolism. Two things will influence the new directions for newborn screening: the development of effective treatments for hitherto untreatable disorders, and advancing technology, enabling new testing strategies to be developed. There are novel treatments on the horizon for many discrete disorders. Susceptibility testing has recently been considered for newborn screening application, but is more controversial. Newborn screening has entered a new and exciting phase, with an explosion of new treatments, new technologies, and, possibly in the future, new preventive strategies.

Efficacy of Congenital Hypothyroidism Neonatal Screening in Preterms less than 32 Weeks of Gestational Age: More Evidence

To evaluate the double screening performed for congenital hypothyroidism (CH) to preterm infants <32 weeks of gestational age (GA) between 1994 and 2003. TSH was assessed by IFMA. Infants were classified as: term (T) (>37 weeks GA); preterm (PT) (33-37 weeks GA); and very preterm (VPT) (< or =32 weeks GA). In 585,221 screened infants, CH was confirmed in 228 T, 23 PT and seven VPT. An increasing incidence of CH was found with decreasing GA, affecting 1:1,603 PT and 1:585 VPT. PT infants had 1.5 times more risk than full-term infants of suffering CH, and VPT 4 times more. Only 4/7 affected VPT had an adequate double screening as requested. Three had elevated TSH values in the first sample and in one a normal TSH (10.3 mIU/l) at 3 days rose to 240 mIU/l after day 15. In the remaining three VPT, TSH in the unique filter paper sample (21 to 34 days) was markedly elevated. Our findings reinforce the need for awareness in neonatal settings for adequate screening of VPT infants. Screening in the first week of life was effective in detection of most but not all affected VPT. Larger studies are needed in order to establish accurate screening recommendations for VPT newborns. Until this step is reached, repeated screening is advised in these infants.

Very low birth weight newborns do not need repeat screening for congenital hypothyroidism

Objective: To determine whether repeat screening for congenital hypothyroidism is necessary in newborns weighing <1500 g (very low birth weight [VLBW]). Study design: All VLBW infants born in the province of Québec between October 15, 1993, and October 15, 1994, had a second filter paper sample requested at 6 weeks of age to measure thyrotropin and thyroxine, in addition to these measurements for the routine screening sample. We then conducted a survey of all 4 academic pediatric endocrinology clinics in the province, inquiring about cases of permanent primary congenital hypothyroidism (PPCH) in children born weighing <1500 g or who may have been missed by neonatal screening. Results: Two specimens were obtained in 465 VLBW newborns. One case of mild transient hyperthyrotropinemia was identified. The survey identified 4 VLBW newborns with PPCH: 1 girl and 1 boy with dyshormonogenesis, 1 athyreotic girl, and 1 girl with thyroid ectopy. All 4 were detected by their initial filter paper specimens. The survey also identified 1 case of PPCH in a girl who had a normal neonatal screen and normal birth weight. Conclusions: VLBW newborns with PPCH can mount an appropriate thyrotropin response and do not need repeat screening for congenital hypothyroidism. (J Pediatr 2002;140:311-4)

Surface enhancement effect on the diffuse reflectance infrared Fourier transform spectra of compounds having a pyridine ring

A surface enhancement effect was examined for the diffuse reflectance infrared spectra of structurally related compounds having a pyridine ring when a silver colloidal solution was used as the medium which induced the effect. Filter paper, which was considered to provide a favorable state of aggregation of the silver colloidal particles, was used for the preparation of the samples to be measured. It was proved experimentally that when the molecules were dissolved in the silver colloidal solution and the resulting solution was applied dropwise to filter paper, the spectra measured for the filter paper sample exhibited a surface-enhanced infrared absorption (SEIRA) effect for some samples, but not for other samples. It was speculated that the existence of an electron-donating functional group in the molecule was necessary for the realization of SEIRA in the diffuse reflectance infrared spectra. This speculation was confirmed by experiments involving other types of molecules: l-phenylalanine, m-aminophenol and p-chloroaniline.

Some considerations of the SERS effect ofL-phenylalanine in the near-infrared region using silver colloid solution

The surface-enhanced Raman scattering (SERS) spectra of L-phenylalanine were examined in the near-infrared region using silver colloid solutions. It was shown that near-infrared SERS (NIR-SERS) was not detected for L-phenylalanine in a normal silver colloid solution, whereas in the visible region a distinct SERS intensity enhancement was realized for such sample systems. In the present study, this situation was considered from the viewpoint that the degree of aggregation of colloid particles necessary to cause the SERS effect is different between visible and near-infrared radiation. In this work, silver colloid solution containing dissolved L-phenylalanine was dropped on to a filter-paper and this filter-paper sample was then dried. It was confirmed by SEM (scanning electron microscopy) that as a result of this sample preparation, the degree of aggregation of colloid particles increased considerably. It was shown that the near-infrared SERS was detected with high sensitivity for L-phenylalanine adsorbed on silver particles condensed on filter-paper. From consideration of the magnitudes of the SERS intensity enhancement in this case, it is suggested that the mechanism of NIR-SERS for the present sample system is the electromagnetic effect, related to the excitation of surface plasmons (the surface plasmon polariton mechanism). © 1997 John Wiley & Sons, Ltd.

FACTORS WHICH INFLUENCE DELAYED OR MISSED NEWBORN SCREENING IN CRITICALLY ILL INFANTS 621

Newborn screening guidelines in North Carolina recommend that the newborn screening test be obtained by filter paper sample prior to discharge(including hospital transfers) regardless of age or within the first 72 hours. Current policy recommends rescreening by 7 days of age if the sample was collected at 80% tested). Delayed or missed screening most often occurred when an infant was transferred multiple times or admitted to other pediatric services. Some factors that contributed to missed screens included early infant death and severe congenital heart disease with some requiring early surgery. Verification of medical record newborn screening data by comparison with state laboratory data is now in progress.

Screening for congenital hypothyroidism – a pilot study in Belgrade

A pilot study in Belgrade was carried out in order to establish optimal conditions for a nation-wide programme in Serbia. We measured TSH on PKU filter paper blood samples by Biodata's neonatal RIA kits. During the first 12 months, beginning in January 1983, 19.972 newborns were screened (97,5% of all live born infants in Belgrade area) and 3 cases confirmed giving an preliminary incidence of 1:6.657. Sixty one infants (0,3%) were recalled for another filter paper sample, but later with cut-off level of TSH above 30 mIU/1 recallrate was 0,07%. Diagnosis was confirmed by Tc99 scan (one infant with aplasia, two with sublingual ectopia of thyroid), and therapy begun at 10-13 days of life. All three female patients had A Rh positive blood group. In the three groups of sick preterm infants with different mean gestational ages (31,0;34,8 and 37,7 weeks, respectively) there were no correlations with TSH values (7,4; 6,7 and 6,2 mIU/l). Neither in healthy term, nor in sick preterm newborns cases of transitory hypothyroidism were found, probably partly because of an efficient iodine prophylaxis of our population.

Development of a filter paper blood spot radioimmunoassay for thyroid stimulating hormone suitable for a regional neonatal screening unit.

The radioimmunoassay described measures TSH in dried whole blood spots collected from neonates onto filter paper Guthrie cards. Microgranular cellulose is added to the precipitating reagent at the critical separation stage of the assay to overcome imprecision caused by the presence of the filter paper sample disc in the tube. The method was developed for a regional neonatal screening unit and has been found to be very reliable during ten months' routine use. It was required to be as precise, sensitive, accurate, rapid, simple, and inexpensive as possible and suitable for use with automatic diluting equipment in order to process large numbers of samples. Other methods were examined for their suitability and found not to fulfil one or more of the above criteria.

THE RELATIONSHIP BETWEEN THE STRUCTURE AND THE FLAMMABILITY OF VARIOUS AROMATIC POLYAMIDES

The purpose of the present investigation is to obtain the relationship between the flammability of various aromatic polymers and their structures. The polymers prepared by the polycondensation reaction in organic polar solvents were examined for their flammability and thermal stability.Limiting Oxygen Index (LOI) test using a conventional filter paper sample was very useful in examining the flammability. Filter paper samples were prepared by the filteration of the precipitants of feathery polymer.Aromatic polyhydrazide, polyurea and poly acyloxyoxalicbisamidrazone did not show selfextinguishingness and good thermal stability. In the case of polyamide, incorporation of methylene groups in the polymer main chain decreased both flammability and thermal stability. So the aromatic polyamide containing aliphatic methylene units did not show self-extinguishingness.On the other hand, wholly aromatic polyamide exhibited much higher thermal stability and flammability. But there was no clear relationship between these two properties. It was verified that iso-oriented polymer is superior in flammability to all-para oriented polymer and generally inferior in thermal stability. The reason may be that the iso-oriented structure is easy to change into crosslinking structure.

Direct-reading beryllium spectrograph.

Abstract A direct-reading emission spectrograph for the quantitative determination of beryllium on one-inch diameter filter paper discs has been developed to relieve the workload on the industrial hygiene chemistry laboratory. The instrument, constructed in our own shops, uses a Bausch and Lomb grating monochromator as its basic unit. Operation of the spectrograph is automatic; the amount of beryllium on the filter paper is read directly from a meter. The filter paper sample discs are used with specially designed high-purity graphite electrodes. Spark excitation of the sample is by a small Bausch and Lomb spark source. The instrument is suitable for detecting concentrations of beryllium ranging from 0.01 to 10 micrograms.

A Rapid Spectrographic Method for the Determination of Beryllium in Air Dust

A method has been developed for the determination of beryllium in air dust samples at the rate of 11 man-minutes per sample. The method involves the use of a small filter paper sample which is inserted into a -cupped graphite electrode and arced in a conventional direct current arc. Certain treatments are necessary to ensure optimum excitation of the sample, including the addition of a barium chloride carrier and internal standard. The method is sensitive to .002 microgram of beryllium on the filter paper, and the range of analysis extends to .1 microgram. The accuracy of the method is about ±30% of the amount of beryllium present.