A simple method to test condoms for penetration by viruses

Cytotoxicity of Formulated Graphene and Its Natural Rubber Nanocomposite Thin Film in Human Vaginal Epithelial Cells: An Influence of Noncovalent Interaction

Graphene family materials (GFMs) are extensively explored for various biomedical applications due to their unique physical properties. The prime challenge is to establish a conclusive safety profile of these nanomaterials and their respective products or devices. Formulating GFMs with appropriate ingredients (e.g., surfactant/compatibilizer) will help to disperse them homogeneously (i.e., within the polymer matrix in the case of polymer–graphene nanocomposites) and aid in good interfacial interaction to achieve the desired properties. However, no cytotoxicity report is available on the effects of the additives on graphene and its incorporated materials. Here, we report in vitro cytotoxicity of formulated FLG (FLG-C), i.e., a mixture of FLG, melamine, and sodium poly(naphthalene sulfonate) (SPS), along with natural rubber (NR) latex and FLG-C-included NR latex nanocomposite (FLG-C-NR) thin films on human vaginal epithelial (HVE) cells. FLG-C shows reduced cellular proliferation (∼55%) only at a longer exposure time (72 h) even at a low concentration (50 μg/mL). It also displays significant down- and upregulation in mitochondrial membrane potential (MMP) and reactive oxygen species (ROS), respectively, whereas no changes are observed in lactate dehydrogenase (LDH), propidium iodide (PI), uptake, and cell cycle analysis at 48 h. In vitro experiments on NR latex and FLG-C-NR latex thin films demonstrate that the incorporation of FLG-C does not compromise the biocompatibility of the NR latex. Further substantiation from the in vivo experiments on the thin films recommends that FLG-C could be suitable to prepare a range of biocompatible rubber latex nanocomposites-based products, viz., next-generation condoms (male and female), surgical gloves, catheters, vaginal rings, bladder–rectum spacer balloon, etc.

Concentration and detection of hepatitis A virus and its indicator from artificial seawater using zeolite

Hepatitis A virus (HAV) infection is the leading worldwide cause of acute viral hepatitis, and outbreaks caused by this virus often occur in fecal polluted waters. Rapid concentration and detection of viral contamination in water environments can prevent economic loss and can identify the source of contamination within a short time. However, conventional methods for virus concentration are often laborious, time consuming, and subject to clogging. Furthermore, most methods require a secondary concentration step to reduce the final volume of samples. We developed a method to concentrate HAV from seawater using zeolite in aid of rapid detection. In this method,artificial seawater was inoculated with HAV (7-8 log TCID50) and filtered with zeolite. The viruses were then eluted from zeolite with sodium dodecyl sulfate and detected via real-time PCR (qPCR). Zeolite was able to concentrate HAV from artificial seawater with ∼99% efficiency in less than 5min and was more efficient in seawater than in fresh water. The entire concentration and detection can be done in approximately 2h. Compared to existing methods, this method eliminated the need for a secondary concentration step as well as the necessity to modify the pH or salinity of the seawater during concentration, and was simple and inexpensive.

Implications of laboratory tests of condom integrity

BACKGROUND

There is sufficient evidence from Food and Drug Administration laboratory experiments and clinical studies to draw conclusions about the relative importance of holes and breakage to condoms. The laboratory test methods determined penetration of viruses or virus-size microspheres through holes in condoms under conditions that simulated or exaggerated those expected in actual use, and determined the frequency with which condoms might pass virus or microspheres and the amounts of passage in each case.

GOALS

To summarize and comment on the significance of test results on latex, polyurethane, and natural membrane condoms as barriers to virus passage.

STUDY DESIGN

Published and unpublished data addressing three distinct concerns were analyzed: (1) passage of virus or microspheres through small holes or pores inherent in the material of "intact" condoms which are undetectable by the standard water leak quality assurance test, (2) passage of virus or microspheres through larger holes in "leaker" condoms detectable by the water leak test but marketed because of the finite acceptable quality level (AQL) of the test, and (3) passage of virus through condoms that break during use.

RESULTS

Extrapolating to the passage of semen expected during actual use allowed an analysis of the relative importance of breakage and water-leak-detectable or water-leak-undetectable holes.

CONCLUSIONS

The relative importance of breaks and holes is related to the volume of semen that contains an "infectious dose" of a sexually transmitted disease (STD). When 0.1 mL to 1.0 mL exposures to semen are necessary for disease transmission, the risk during latex condom use primarily results not from holes, but from breakage of condoms. For smaller volumes of semen exposure (0.00001 mL and less), the presence of holes can be as important as breaks. The same qualitative argument pertains to a comparison of "leaker" condoms to the large majority of "intact" condoms.

Evaluation of endoscope sheaths as viral barriers

OBJECTIVES

Evaluate ENT endoscope sheaths as barriers to virus passage.

STUDY DESIGN

"Defective" sheaths covering an endoscope were challenged with virus to determine how many virus particles could be recovered from the endoscope.

METHODS

Sheaths with small laser-drilled holes (2 to 30 microm) were challenged with high-titer virus suspensions (10(8) viruses/mL). The inside of the sheath and the endoscope were separately rinsed to recover any virus that penetrated through the hole in the sheath. In an attempt to assess the possible importance of holes in the sheaths, a sequential test was conducted with an initial virus challenge outside a defective sheath (30-micron hole in the sheath), after which the possibly contaminated endoscope was removed and inserted into a second defective sheath (with a 20-micron hole at the same location) to determine whether the contaminating virus would pass outward through the second sheath.

RESULTS

Small volumes of virus-containing fluid penetrated through the hole, e.g., 500 virus particles passed through one of three 30-microm holes. A significant fraction of those virus particles was occasionally found on the endoscope after removal from the sheath. Similar results were obtained with sheaths that had small tears (34-84 microm in length, from punctures with fine wires). Although some virus penetration could occur during the initial challenge contaminating the endoscope, no virus was detected passing outward through the second sheath.

CONCLUSIONS

Use of a sheath combined with intermediate level disinfection should provide a safe instrument for ENT endoscopy.

An in vitro evaluation of condoms as barriers to a small virus

BACKGROUND

Because of the possible presence of small holes, the effectiveness of condoms as barriers to virus transmission is controversial.

GOALS

To determine the proportion of condoms that allow virus penetration and the amounts of virus that penetrate.

STUDY DESIGN

A sensitive, static test was used to evaluate different condom types as barriers to a small virus, including brand with or without lubrication and ones of different materials. The test included some physiologic-based parameters and some parameters that exaggerated expected actual use conditions.

RESULTS

Under test conditions, 2.6% (12 of 470) of the latex condoms allowed some virus penetration; the median level of penetration was 7 x 10(-4) ml. Lubricated condoms performed similarly to nonlubricated ones. Polyurethane condoms yielded results higher than but not statistically different from those for latex condoms.

CONCLUSIONS

Few condoms allowed any virus penetration. The median amount of penetration for latex condoms when extrapolated to expected actual use conditions was 1 x 10(-5) ml (volume of semen). Thus, even for the few condoms that do allow virus penetration, the typical level of exposure to semen would be several orders of magnitude lower than for no condom at all.

Elution of viruses by ionic and nonionic surfactants

The ionic and nonionic surfactants sodium dodecyl sulfate and Triton X-100, respectively, eluted two viruses, phi X174 and PRD1, which were adsorbed to the ionic and nonionic binding membranes cationic polysulfone and nitrocellulose, respectively. Results indicated that complete elution was readily achieved only when combinations of surfactants and binding membranes were matched (i.e., ionic-ionic or nonionic-nonionic).

The benefits of school-based condom availability: cross-sectional analysis of a comprehensive high school-based program

OBJECTIVES

To analyze the benefits of a school-based condom availability program relative to the risks that such a program may incur.

METHODS

A confidentially-administered survey instrument was completed by 152 randomly selected high-school students (approximately 14% of the entire student population).

RESULTS

The respondents had a mean age of 15.9 years (range: 14-19 years) and a proportionate gender distribution. Ninety-three percent of all respondents had "heard of" the school's program and knew from whom they could receive condoms. Twenty-six percent of the respondents had received condoms from the program with 67% using them. Of those receiving condoms but not using them, more than half did not need them, owing to absence of anticipated sexual activity. Of the nonreceivers, 53% had never had sexual intercourse and 27% received condoms from other sources. The benefit of the program by aiding a sexually-active student was found to be more than three times as great as the risk of encouraging a nonsexually active student to have sexual intercourse (RR = 3.2; 95% C.I. = 2.1, 4.9). The prevalence of sexual activity among all respondents was not significantly higher than the state's average based on gender and age (59.8% vs. 54.5%; z = 1.24, p > .05, n.s.).

CONCLUSION

Given the lack of increased sexual activity and the favorable benefit-risk ratio, we conclude that school-based condom availability is successfully utilized by sexually-active adolescents and may be an effective means to reduce potentially harmful outcomes, such as unintended pregnancy and sexually-transmitted diseases.

Minimized virus binding for tests of barrier materials

Viruses are used to test the barrier properties of materials. Binding of virus particles during passage through holes in the material may yield misleading test results. The choices of challenge virus and suspending medium may be important for minimizing confounding effects that might arise from such binding. In this study, different surrogate viruses, as well as different support media, were evaluated to determine optimal test parameters. Two membranes with high-binding properties (nitrocellulose and cationic polysulfone) were used as filters to compare binding activities of different surrogate challenge viruses (MS2, phi X174, T7, PRD1, and phi 6) in different media. The media consisted of buffered saline with surfactants, serum, or culture broth as additives. In addition, elution rates of viruses that bound to the membranes were determined. The results suggest that viruses can bind by hydrophobic and electrostatic interactions, with phi X174 displaying the lowest level of binding by either process. The nonionic detergents Triton X-100 and Tween 80 (0.1%) equally minimized hydrophobic interactions. Neither anionic nor cationic surfactants were as effective at nontoxic levels. Serum was effective at reducing both hydrophobic and electrostatic binding, with 2% being sufficient for eliminating binding under our test conditions. Thus, phi X174 remains the best choice as a surrogate virus to test barrier materials, and Triton X-100 (0.1%) remains a good choice for reducing hydrophobic binding. In addition, binding of viruses by barrier materials is unlikely to prevent passage of blood-borne pathogens.