Characterizing the transplanar and in-plane water transport properties of fabrics under different sweat rate: Forced Flow Water Transport Tester.

The water absorption and transport properties of fabrics are critical to wear comfort, especially for sportswear and protective clothing. A new testing apparatus, namely Forced Flow Water Transport Tester (FFWTT), was developed for characterizing the transplanar and in-plane wicking properties of fabrics based on gravimetric and image analysis technique. The uniqueness of this instrument is that the rate of water supply is adjustable to simulate varying sweat rates with reference to the specific end-use conditions ranging from sitting, walking, running to other strenuous activities. This instrument is versatile in terms of the types of fabrics that can be tested. Twenty four types of fabrics with varying constructions and surface finishes were tested. The results showed that FFWTT was highly sensitive and reproducible in differentiating these fabrics and it suggests that water absorption and transport properties of fabrics are sweat rate-dependent. Additionally, two graphic methods were proposed to map the direction of liquid transport and its relation to skin wetness, which provides easy and direct comparison among different fabrics. Correlation analysis showed that FFWTT results have strong correlation with subjective wetness sensation, implying validity and usefulness of the instrument.

Characterizing the transplanar and in-plane water transport of textiles with gravimetric and image analysis technique: Spontaneous Uptake Water Transport Tester.

Water absorption and transport property of textiles is important since it affects wear comfort, efficiency of treatment and functionality of product. This paper introduces an accurate and reliable measurement tester, which is based on gravimetric and image analysis technique, for characterising the transplanar and in-plane wicking property of fabrics. The uniqueness of this instrument is that it is able to directly measure the water absorption amount in real-time, monitor the direction of water transport and estimate the amount of water left on skin when sweating. Throughout the experiment, water supply is continuous which simulates profuse sweating. Testing automation could even minimise variation caused by subjective manipulation, thus enhancing testing accuracy. This instrument is versatile in terms of the fabrics could be tested. A series of shirting fabrics made by different fabric structure and yarn were investigated and the results show that the proposed method has high sensitivity in differentiating fabrics with varying geometrical differences. Fabrics with known hydrophobicity were additionally tested to examine the sensitivity of the instrument. This instrument also demonstrates the flexibility to test on high performance moisture management fabrics and these fabrics were found to have excellent transplanar and in-plane wicking properties.

Determination of hepatitis E virus seroprevalence by using recombinant fusion proteins and synthetic peptides.

Recombinant antigens from hepatitis E virus (HEV) open-reading frames 2 and 3 were expressed in Escherichia coli as cytidine monophosphate-2-keto-3-deoxyoctulosonic acid synthetase (CKS) fusion proteins, purified, and used to develop an EIA for the detection of antibodies. Serologic results were compared with those of previous assays by testing 102 samples from an HEV outbreak in Somalia. This CKS/HEV EIA detected anti-HEV in all 97 sera found reactive previously and in an additional 2 samples, which were shown to be true HEV-positive samples by supplemental peptide and Western blot tests. The CKS/HEV EIA and supplemental assays were then used to determine seroprevalence of HEV worldwide. HEV seroprevalence ranged from 1% to 25%, with higher rates found in Middle Eastern countries. Also, 7%-14% of acute cases of non-A, -B, or -C hepatitis were HEV-positive. Thus, this CKS/HEV EIA appears useful for detecting anti-HEV in various populations.

Detection of IgA class antibody to hepatitis E virus in serum samples from patients with hepatitis E virus infection.

A newly developed assay for IgA class antibody to hepatitis E virus (IgA anti-HEV) was used to study 145 serum samples collected during an outbreak of an enterically transmitted hepatitis that occurred in 3 villages in the lower Shebeli region of Southern Somalia between January, 1988 and November, 1989. A total of 52.4% of the afflicted patients were found positive for IgA anti-HEV, and 73.1% of these were also positive for IgM. Both antibodies disappeared during the convalescence period. Similar results were also seen in serum obtained from sporadic cases of acute waterborne hepatitis in Pakistan.

Solid-phase enzyme-linked immunosorbent assay for hepatitis E virus IgG and IgM antibodies utilizing recombinant antigens and synthetic peptides.

Four recombinant antigens representing two distinct antigenic domains from two different strains of hepatitis E virus (HEV), were used individually to develop four ELISAs designed to detect antibodies to HEV. Both IgG and IgM class antibodies to HEV were detected in 7 of 8 pedigreed serum/plasma from known outbreaks of HEV in Mexico, Burma, Somalia and Pakistan. In addition, specific HEV-antibodies were detected in cynomolgus macaques following inoculation with various HEV strains. Anti-HEV was also detected in 8 of 386 (2.1%) randomly selected American blood donors. Supplemental tests utilizing both synthetic peptides and specific blocking assays provided additional serologic data confirming the presence of anti-HEV. Similar prevalence studies on a limited number of available sera from other geographical regions (Alaska, Japan, Germany, New Zealand, Thailand and Mexico) confirmed the presence of anti-HEV in at least 1.1 to 7.6% of the specimens.

IgM-antibody response to hepatitis C virus antigens in acute and chronic post-transfusion non-A, non-B hepatitis.

A specific IgM solid-phase enzyme-linked immunoassay for the diagnosis of a recent infection by hepatitis C virus (HCV) was developed. The assay utilizes a structural antigen encoded by sequences at the 5' end of HCV (core region) and non-structural (NS) antigens encoded by the NS-3 (33c) and NS-4 (c100-3) regions of the HCV genome. Serial serum samples from several clinically diagnosed post-transfusion non-A, non-B hepatitis patients were analyzed for anti-HCV IgM. This antibody was frequently but transiently detected. Anti-HCV core IgM was more frequently detected than anti-c100-3 or anti-33c IgM. In individuals who resolved their HCV infection or progressed to chronicity, anti-HCV IgM was produced transiently at or near the onset of clinically diagnosed acute hepatitis.

Evaluation of enzyme immunoassay for anti-HBc IgM in the diagnosis of acute hepatitis B virus infection.

Corzyme-MTM (Abbott Laboratories, North Chicago, IL), a newly introduced kit for the measurement of serum IgM antihepatitis B core antigen by enzyme immunoassay, was evaluated for the diagnosis of acute B-viral hepatitis (AVH-B). The study included 175 acute viral hepatitis patients with transient hepatitis B surface antigen (HBsAg). Sera from 160 were tested on multiple occasions until their HBsAg cleared. IgM anti-HBc was found in 171 of 175 patients (98.4%) during the acute phase. The serum samples from 42 patients with liver biopsy-proven chronic active hepatitis, type B (CAH-B), and 18 patients with persistent hepatitis, type B (PH-B), were analyzed for the presence of IgM anti-HBc, using the same technic. None of the sera from 42 patients with CAH-B and only 2 of the 18 patients with PHB had IgM anti-HBc. Thus, the measuring IgM anti-HBc using Corzyme-M kit is helpful in the diagnosis of AVH-B and in the discrimination of acute from chronic HBV infections.

Anti-hepatitis B core immunoglobulin M in the serologic evaluation of hepatitis B virus infection and simultaneous infection with type B, delta agent, and non-A, non-B viruses.

The clinical value of an enzyme-linked immunosorbent assay for the detection of immunoglobulin M (IgM) antibody to hepatitis B core antigen (anti-HBc IgM) was evaluated by testing serum samples from the following groups of patients: (a) 27 individuals who had been diagnosed as having acute hepatitis B virus (HBV) infection, (b) 29 hepatitis B surface antigen (HBsAg) carriers, (c) 6 subjects with acute non-B hepatitis, and (d) 10 HBsAg-negative but anti-HBc-positive subjects who were suspected of being index cases for the intimate transmission of HBV. Whereas 24 of the 27 individuals with presumed acute HBV infection exhibited anti-HBc IgM, only 2 of 29 HBsAg carriers were found to be positive. Hepatitis B surface antigen persisted during an 8-mo observation period in 3 anti-HBc IgM-negative subjects with acute HBsAg-positive hepatitis. Before anti-HBc IgM testing, it was considered that these cases had evolved to the HBsAg carrier state. However, the regular demonstration of anti-HBc IgM in acute type B hepatitis, as well as the failure to detect this antibody in the majority of HBsAg carriers, led to reclassification of these cases as probable instances of acute non-A, non-B or delta-agent hepatitis superimposed on the HBsAg carrier state. Through additional testing, the diagnosis of non-A, non-B (NANB) infection was confirmed in 2 of these cases, and delta-agent infection was identified in the third. None of the non-B hepatitis cases exhibited anti-HBc IgM. However, 5 of the 10 suspected type B index cases were anti-HBc IgM-positive, indicating that they were very recently infected and most likely had infected their cohabiting sexual partners. The results from this study indicate that testing for anti-HBc IgM may improve serodiagnostic accuracy when acute NANB and delta-agent hepatitis occur in previously unrecognized HBsAg carriers. Moreover, it may be a useful test in defining potential high risk sources of exposure to HBV.

Serodiagnosis of recent hepatitis B infection by IgM class anti-HBc.

The time sequence, relative reactivity, and persistence of anti-HBc IgM were assessed in patients with HBsAg-positive viral hepatitis. A solid-phase immunoassay was developed using the IgM capture procedure with anti-mu-coated polystyrene beads. HBcAg was purified from serum Dane particles and used as a probe with 125I-labeled anti-HBc IgG. This immunoassay exhibited a pronounced prozoning phenomenon, and relative titers of sera differed widely depending upon the dilution of serum tested. When all sera were tested at 1:5,000 dilution, results were comparable in different patient groups. Anti-HBc IgM persisted at detectable levels for up to 2 years, and it was necessary to establish relative titers to discriminate current from remote infections. A cut-off assay value was established, and in 12 cases of acute hepatitis B virus (HBV) infection, antibody exceeded this value for about 6 months after onset of HBs antigenemia. A similar profile of anti-HBc IgM persistence was observed in seven patients who developed an HBsAg chronic carrier state. Long-term viral replication did not sustain elevated IgM class-specific antibody levels. The studies suggest that anti-HBc IgM analyses may be useful for differentiating recent and current HBV infections from remote infections, eliminating HBV as the agent for non-A, non-B hepatitis in asymptomatic HBsAg carriers, and detecting HBV as the etiologic agent during silent (HBsAg negative) infections.

A new extractant for serum thyroxine by enzymatic digestion of thyroxine binding proteins.

The use of a pepsin solution to digest serum proteins results in quantitative release of thyroxine from carrier proteins. This extraction method greatly simplifies the original Murphy and Pattee (1) competitive protein-binding assay for serum thyroxine. The simplicity and efficiency of this extractant suggest that it may have application in radioimmunoassay and competitive protein-binding assay for nonpeptide ligands in serum.