Safer school with near-UV technology: novel applications for environmental hygiene.

Systems capable of disinfecting air and surfaces could reduce the risk of infectious diseases transmission. Aim: to evaluate the effectiveness of near-UV LED ceiling lamps, with a wavelength of 405 nm, in improving environmental hygiene. Between November and December 2020, we conducted an experimental study having a pre-post design in a kindergarten room in Siena where 4 ceiling lamps with 405 nm LED technology were installed. Twice per day, sampling was performed before (T0) and after treatment with near-UV (T1). We used between 8 and 12 pairs of contact plates to sample at various random spots each day. Air samplings were also performed. The plates were incubated at 22 and 36 °C. Significance was set at 95% (p < 0.05). The mean level of Colony Forming Unit (CFU) at T(0) was 249 (95% CI 193.1 - 305.0) at 36 °C and 535.2 (374.3 - 696.1) at 22 °C. The reduction was significant at T(1): by 65% at 36 °C and, 72% at 22 °C. Also, for air contamination: 95.3% (98.4-92.3). A dose threshold of about 5 J/cm2 was identified to have an 80% CFU abatement and remains nearly constant. The advantage of being able to use this technology in the presence of people is very important in the context of controlling environmental contamination.

Disinfecting Slush Machines by an Innovative Near Ultraviolet Light Emitting Diode (UV LED) Technological System.

Background: Microbial contamination of food and beverages is a topic of great interest. The most innovative technologies take advantage from UV light. This study aimed to evaluate a possible configuration of a nUV LED device at a wavelength of 405 nm installed on slush machines in order to reduce the microbial contamination. Study Design and Methods: Study Design and Methods. The study was conducted in the Department of Molecular and Developmental Medicine, University of Siena, Italy. A nUV LED device with 408 nm wavelength was installed and used on the slush machines. The inner walls of the machine tanks were fouled with contaminated slush, to evaluate the effectiveness of nUV radiation in reducing microbial contamination over time. Results: Experiment results on the slush machine showed a statistically significant logarithmic microbial reduction, in relation with the distance from the nUV LED light source. It has also been shown that the reduction of microbes is possible with a proper management of some parameters: the exposure time, the power and wavelength of the light source, the distance and the obstacles between the light source and the target to be irradiated. Conclusion: To reduce the incidence of foodborne diseases it is necessary to take all necessary precautionary measures, and the use of nUV technology has proved to be a crucial element in achieving this goal.

Wind of change: Better air for microbial environmental control.

Background: The COVID19 epidemic highlighted the importance of air in the transmission of pathogens. Air disinfection is one of the key points to reduce the risk of transmission both in the health sector and in public, civil and industrial environments. All bacteria and viruses tested to date can be inactivated by UV-C rays. Laboratory tested UV-C systems are increasingly popular and proposed as effective technologies for air purification; few studies have evaluated their performance in populated indoor environments. The aim of this investigation was to evaluate the effectiveness of a UV-C disinfection system for air in a real working context. Methods: This experimental study was conducted between December 2020 and February 2021 in an office of the Department of Molecular and Developmental Medicine of the University of Siena, Italy. A pre-final version air purifier (Cleaning Air T12), capable of treating 210 m3/h of air, was first tested for its ability to filter particulates and reduce microbial air contamination in the absence of people. Subsequently, the experiments were conducted in the presence of 3-5 subjects who worked for several hours in an office. During the tests, microbiological samples of air were collected in real time, switching the system on and off periodically. Air samples were collected and incubated on Petri dishes at 36 °C and 22 °C. Statistical analysis was performed with Stata 16 software assuming a significance level of 95%. An interpolating model was identified to describe the dynamics of contamination reduction when the device operates. Results: Preliminary tests showed a significant 62.5% reduction in Colony-Forming Units (CFUs) with 36 °C incubation. Reductions in the particulate component were also observed. In the main test, comparison of CFU data, between the device-on phase (90 min) and the subsequent device-off phase (60 min), showed statistically significant increase (p = 0.001) of environmental contamination passing from a mean of 86.6 (65.8-107.4) to 171.1 (143.9-198.3) CFU/m3, that is a rise of about 100%. The interpolating model exhibited a good fit of CFU reduction trend with the device on. Conclusions: The system, which mainly uses UV-C lamps for disinfection, was able to significantly reduce environmental and human contamination in real time. Experimental tests have shown that as soon as the device is switched off, after at least half an hour of operation, the healthiness of the air decreases drastically within 10 minutes, bringing the airborne microbial contamination (induced by the presence of operators in the environment) to levels even higher than 150% of the last value with the device on. Re-engineering strategies for system improvement were also discussed.

Rapid detection of Legionella spp in water samples by ScanVIT method: comparison of acid vs heat treatment.

BACKGROUND: A rapid detection of Legionella bacteria in water samples is crucial to minimize the risk of acquiring infections, especially in health care facilities. Different detection methods and different decontamination procedures have been reported to affect the recovery of Legionella spp. Our goal was to test the recovery of Legionella pneumophila and Legionella non-pneumophila species using a kit based on non-specific and species-specific probes to treat water samples after two different decontamination procedures. METHODS: The study was conducted with samples collected in the teaching hospital "Le Scotte" of Siena (Italy). Waters samples were analyzed by: i) ScanVIT method after treatment with acids; ii) ScanVIT method after heating; and iii) cultural standard method after heating. The results of the decontamination procedures and the detection methods were evaluated by comparing the number of Legionella-positive and -negative samples, and the recovery rates (CFU l-1) obtained by ScanVIT and the standard method. RESULTS: We find that ScanVIT method is highly sensitive with both decontamination treatments, yielding a higher recovery of L. pneumophila compared to the standard method. Conversely, ScanVIT associated with the acid-treatment yielded the highest recovery of L. non-pneumophila. CONCLUSIONS: The acid-treatment combined to the ScanVIT method increases the recovery of L. non-pneumophila in water samples compared to both ScanVIT associated with heat-treatment and standard culture method. Thus, this method may represent the best choice to detect L. non-pneumophila in water samples and reduce the risk of infection due to underestimation of Legionella loads.

5HT2A receptor blockade in dorsomedial striatum reduces repetitive behaviors in BTBR mice.

Restricted and repetitive behaviors are a defining feature of autism, which can be expressed as a cognitive flexibility deficit or stereotyped, motor behaviors. There is limited knowledge about the underlying neuropathophysiology contributing to these behaviors. Previous findings suggest that central 5HT2A receptor activity is altered in autism, while recent work indicates that systemic 5HT2A receptor antagonist treatment reduces repetitive behaviors in an idiopathic model of autism. 5HT2A receptors are expressed in the orbitofrontal cortex and striatum. These two regions have been shown to be altered in autism. The present study investigated whether 5HT2A receptor blockade in the dorsomedial striatum or orbitofrontal cortex in the BTBR mouse strain, an idiopathic model of autism, affects the phenotype related to restricted and repetitive behaviors. Microinfusion of the 5HT2A receptor antagonist, M100907 into the dorsomedial striatum alleviated a reversal learning impairment and attenuated grooming behavior. M100907 infusion into the orbitofrontal cortex increased perseveration during reversal learning and potentiated grooming. These findings suggest that increased 5HT2A receptor activity in the dorsomedial striatum may contribute to behavioral inflexibility and stereotyped behaviors in the BTBR mouse. 5HT2A receptor signaling in the orbitofrontal cortex may be critical for inhibiting a previously learned response during reversal learning and expression of stereotyped behavior. The present results suggest which brain areas exhibit abnormalities underlying repetitive behaviors in an idiopathic mouse model of autism, as well as which brain areas systemic treatment with M100907 may principally act on in BTBR mice to attenuate repetitive behaviors.

Papanicolaou staining of exfoliated vaginal epithelial cells facilitates the prediction of ovulation in the giant panda.

The giant panda is seasonally monoestrus, experiencing a single estrous with spontaneous ovulation in the spring. Therefore, accurate monitoring of the estrous cycle to pinpoint the time of ovulation is critical for the success of timed mating or artificial insemination. Analysis of exfoliated vaginal epithelial cells is a simple technique that rapidly yields information about the estrous status of a panda. Vaginal swabs were obtained during five estrous cycles of two nulliparous females. Cells were stained with the trichrome Papanicolaou and classified as basophils, intermediates or superficials. The color of stained cells, basophilic, acidophilic or keratinized, was recorded as a characteristic independent of the three standard cell types. The day urinary conjugates of estrogen fell from peak levels was considered the day of ovulation. A chromic shift occurred 8-9 days before ovulation when the majority of exfoliated vaginal cells changed from basophilic (blue) to acidophilic (pink) without accompanying nuclear or cytoplasmic changes. A second chromic shift was consistently observed 2 days prior to ovulation when keratinized (orange) cells replaced acidophils as the majority of vaginal cells. Monochrome staining of vaginal cells is sufficient to quantify superficial cells, which is a useful adjunct to behavioral and endocrinological data in determining estrous in the giant panda. However, the timing and duration of superficial cell elevations are substantially different between and within individual females, which limits the accuracy of timing ovulation for artificial insemination. The predictive value of vaginal cytology was greatly enhanced with the trichrome stain and evaluation of cell color.

Expression of developmentally regulated crypt cell antigens in human and rat intestinal tumors.

The expression of 5 antigens specific for adult intestinal crypt cells and defined by monoclonal antibodies prepared to surface membrane components of the human colon tumor cell line CaCo-2 was studied during fetal and postnatal development of Sprague-Dawley rat small and large intestines. In the small intestine, all epithelial cells were stained during fetal life; antigen distribution became restricted to the crypt and lower villus cells in suckling animals and to the crypt cells after weaning. In the colon, these antigens could be detected only during a short period of development, comprising the last 3-4 days of fetal life and the first 8-10 days after birth. Expression of the antigens defined by this group of antibodies was investigated in rat intestinal tumors induced by 1,2-dimethylhydrazine (CAS: 540-73-8) and in normal and diseased human colons. In rats, these antigens were detected in all poorly and moderately differentiated adenocarcinomas of the small and large intestines. In most specimens, antigen distribution was not uniform; intensely stained areas were surrounded by completely negative tumor regions. Antigen expression was less intense in well-differentiated tumors, and about half of the tumors were negative for antigen expression. A similar pattern of expression of these antigens was observed in all human colonic adenocarcinomas examined; all samples of normal colon, benign polyps, and inflammatory bowel diseases examined were negative. These results suggest that this group of monoclonal antibodies recognizes oncofetal rat antigens expressed in chemically induced rat intestinal tumors and human colonic adenocarcinomas.

The hemodynamic effects of the sclerosant sodium morrhuate in dogs.

The hemodynamic effects of systemic administration of 5 per cent sodium morrhuate was evaluated in normal dogs. Dogs in the control group were injected with 2 per cent benzyl alcohol with pH adjusted to 9.5. Animals injected with sodium morrhuate had a significant reduction in cardiac output, arterial blood pressure, portal vein and hepatic artery flows. These changes occurred primarily in the first 30 minutes of observation. In response to the reduction of the hepatic blood flow, there was an increase in portal vein pressure and resistance.