Sources of SARS-CoV-2 and Other Microorganisms in Dental Aerosols.

On March 16, 2020, 198,000 dentists in the United States closed their doors to patients, fueled by concerns that aerosols generated during dental procedures are potential vehicles for transmission of respiratory pathogens through saliva. Our knowledge of these aerosol constituents is sparse and gleaned from case reports and poorly controlled studies. Therefore, we tracked the origins of microbiota in aerosols generated during ultrasonic scaling, implant osteotomy, and restorative procedures by combining reverse transcriptase quantitative polymerase chain reaction (to identify and quantify SARS-CoV-2) and 16S sequencing (to characterize the entire microbiome) with fine-scale enumeration and source tracking. Linear discriminant analysis of Bray-Curtis dissimilarity distances revealed significant class separation between the salivary microbiome and aerosol microbiota deposited on the operator, patient, assistant, or the environment (P < 0.01, analysis of similarities). We also discovered that 78% of the microbiota in condensate could be traced to the dental irrigant, while saliva contributed to a median of 0% of aerosol microbiota. We also identified low copy numbers of SARS-CoV-2 virus in the saliva of several asymptomatic patients but none in aerosols generated from these patients. Together, the bacterial and viral data encourage us to conclude that when infection control measures are used, such as preoperative mouth rinses and intraoral high-volume evacuation, dental treatment is not a factor in increasing the risk for transmission of SARS-CoV-2 in asymptomatic patients and that standard infection control practices are sufficiently capable of protecting personnel and patients from exposure to potential pathogens. This information is of immediate urgency, not only for safe resumption of dental treatment during the ongoing COVID-19 pandemic, but also to inform evidence-based selection of personal protection equipment and infection control practices at a time when resources are stretched and personal protection equipment needs to be prioritized.

Molecular expression and identification of caprine estrogen receptor gene 1 for fertility status in bucks.

Estrogen and its receptors are essential for sexual development and reproduction. Oestrogen receptor alpha (ERα) is a nuclear receptor activated by the hormone oestrogen. In male, ERα is encoded by the gene ESR1 (oestrogen receptor1) responsible for better fertility. ESR1 is involved in the reabsorption of luminal fluid during the transit of spermatozoa from the testis to the head of the epididymis which is important for their survival and maturation during epididymal storage. The absence of ESR1 leads to reduced epididymal sperm content, reduced sperm motility and fertilizing ability. The present study was undertaken to investigate the expression and presence of ESR1 gene in fertile and low-fertile male goat breeds. We identified ESR1 gene through various molecular tools. Genotyping was carried out by high resonance melting analysis using Roche Light Cycler 480(LC-480) system and found three different genotypes. Genotypic frequency-AA (blue-0.67), BB(Red-0.2), AB(Green-0.08) with allele frequency A(0.71 and B (0.29). The predominance of this gene in head of epididymis in fertile bucks was confirmed by SDS-PAGE, Western blotting and immunohistochemistry. From the results, we corroborated that the present study provides a useful and effective way to predict male fertility in goat breeds, which in turn increases the percentage of fertility in flock leading to more number of offspring in a kidding season.

Estrogen receptor gene 1 expression in caprine and its effect on fertility.

The present study was undertaken to analyze the expression pattern of estrogen receptor 1 gene (ESR1) in Barbari bucks (fertile and non-fertile) identified on the basis of seminal quality traits and fertility trials. RNA was extracted from the spleen by Trizol method. The expression pattern of ESR1 gene was analyzed using real time polymerase chain reaction (RT-PCR). The expression pattern of ESR1 gene was analyzed by RT-PCR (Roche LC-480). Relative quantification by RT-PCR indicated that the ESR1 gene expression showed more fold in fertile bucks as compared to non-fertile.

Molecular expression of caprine estrogen receptor gene 1 in reproductive and non-reproductive tissues.

During the last decades, physiological effects of oestrogens have been increasingly explored by scientists and biotechnologists. Estrogens exert a wide range of effects on a large variety of cell types. Oestrogen and its receptors are essential for sexual development and reproduction. Estrogen receptor alpha is a nuclear receptor activated by the hormone oestrogen. In male, ERα is encoded by the gene estrogen receptor gene 1 (ESR1), responsible for better fertility. The ESR1 is involved in the reabsorption of luminal fluid during the transit of spermatozoa from the testis to the head of the epididymis which is important for their survival and maturation during epididymal storage. The absence of ESR1 leads to reduced epididymal sperm content, reduced sperm motility and fertilizing ability. Therefore, this is a good startby to study the expression pattern of estrogen receptor 1 gene in high-fertile (G1) and low-fertile (G2) bucks of Jamunapari and Barbari breeds identified on the basis of seminal quality traits and fertility trials. RNA was extracted from the tissues by TRIzol method. The identification and expression pattern of caprine ESR1 gene was analysed by real-time PCR (Roche LC-480). Our work shows that the relative quantification by RT-PCR indicates more fold in head of epididymis as compared to spleen of caprine ESR1 gene. Furthermore, the RT-PCR indicated that fertile bucks of Jamunapari breed have more fold value as compared to Barbari breed in respect of reproductive organ.

Serological monitoring of thalassaemia major patients for transfusion associated viral infections.

A total of 39 patients with thalassaemia major who received multiple blood transfusions were followed up clinically and serologically for 3 successive years (1993, 1994, 1995). They were screened for hepatitis B surface antigen (HBsAg), and antibodies to hepatitis B core (HBc-total), hepatitis C virus (HCV), human immunodeficiency virus I and II (HIV-I/II) and cytomegalovirus (CMV-total). In spite of transfusing HBsAg screened (by third generation ELISA) blood from voluntary non-remunerated donors, there was a significant increase of HBsAg positivity (P < 0.001) from 17.9 per cent (1993) to 35.9 per cent (1994) to 69.2 per cent (1995). This was probably due to the prevalence of undetectable HBV infection in the population. Anti HBc was present in 17 (43.6%), 14 (35.9%) and 16 (41%) patients in consecutive years. An increase in the units of blood transfused was observed every year. Blood units were not screened for anti HCV antibodies but a gradual increase in positivity [9 (23%), 12 (30.7%) and 14 (35.9%) patients] was seen in consecutive years. Anti-HIV antibodies were found in a 16 yr old male who was included in the study without any clinical evidence of AIDS. Anti CMV antibody was found in 30 (76.9%), 32 (82%) and 29 (74.3%) patients without any apparent clinical infection. Some patients showed change of antibody pattern (from negative to positive or vice versa) and a few patients showed inconsistent results probably due to immune modulation. Recruitment of 'repeat' non-remunerated voluntary blood donors may reduce the risk of high HBV transmission.

Post-transfusion hepatitis type B following multiple transfusions of HBsAg-negative blood.

BACKGROUND/AIMS: Post-transfusion hepatitis continues to occur, though with decreasing frequency, even after screening donor blood for HBsAg, anti-HBc, anti-HCV and alanine aminotransferase activity. Data from developing countries on the frequency and type of post-transfusion hepatitis are scarce. We undertook this prospective study to determine the incidence and type of post-transfusion hepatitis at our center after transfusion of blood negative for HBsAg by ELISA. METHODS: Forty-one patients undergoing open-heart surgery, who had received 3 or more units of HBsAg-negative blood, were followed up. Serum samples of donor units transfused to recipients who developed post-transfusion hepatitis-B were subjected to HBV DNA amplification by the polymerase chain reaction, using two sets of X-gene specific primers which amplified a 250-bp fragment of the HBV DNA. RESULTS: We found that six of the 41 patients (14.6%) developed post-transfusion hepatitis; four of them (66.6%) developed icteric post-transfusion hepatitis B, whereas two (33.3%) developed anicteric post-transfusion hepatitis C. These six recipients received a total of 48 units of blood and 30 of these 48 units could be subjected to HBV DNA amplification by polymerase chain reaction. Eleven donor samples were polymerase chain reaction positive and had been transfused to three of the four patients who had developed post-transfusion hepatitis B. CONCLUSIONS: We conclude that post-transfusion hepatitis B continues to be the most common cause of post-transfusion hepatitis in India. Screening of donor units for HBsAg by ELISA does not exclude all blood units infectious for hepatitis B virus. Additional measures to ensure safety of blood supply should be sought.

Relationship of serum alanine aminotransferase (ALT) to body mass index (BMI) in blood donors: the need to correct ALT for BMI in blood donor screening.

A study was carried out on 1,028 voluntary blood donors to see how body mass index (BMI) correlated with the serum alanine amino transferase (ALT) activity. The mean ALT (U/l) values were 19.35, 27.63, 40.79 and 54.41 in the four BMI categories of < or = 20, 20.1-25, 25.1-30 and > 30, respectively. This study showed that the mean serum ALT level of obese subjects (BMI > 30 kg/m2), compared with the two categories of normal subjects (i.e. BMI < or = 20 and BMI = 20.1-25 kg/m2), was increased by 2.8 and 1.96 times, respectively. Compared with the BMI group < or = 20, there was a gradual per cent increase in the mean serum ALT in the three different BMI groups: 20.1-25 (+133%), 25.1-30 (+196%) and > 30 kg/m2 (+280%). This indicates the need to correct ALT values for BMI for blood donor screening, instead of using actual ALT values.

Effectiveness of mandatory transmissible diseases screening in Indian blood donors.

This study was undertaken to determine the prevalence of transfusion transmitted diseases (TTDs) among local blood donors, the safety offered by the four mandatory tests (for HIV, HBsAg, syphilis and malaria) and to assess alanine aminotransferase (ALT) as a surrogate test. A total of 313 blood donors were tested for HBsAg, hepatitis B core (HBc) antibody, hepatitis C (HCV) antibody, HIV antibody, and IgM antibody to cytomegalovirus (CMV-IgM). The serum alanine aminotransferase levels were also done on each unit of blood. The prevalence of various markers was 7(2.2%) for HBsAg, 57 (18.2%) for anti HBc (total), 1 (0.3%) for anti HCV, 16 (5.1%) for anti CMV. None of the donors were positive for HIV, VDRL or malaria. ALT level was raised in 16.5 per cent of donors and showed no correlation with hepatitis markers. ALT was not found to be useful as a surrogate marker for routine screening of donors. Sensitive tests like ELISA and immunofluoresence for malaria antigen should be applied for screening for malaria. VDRL test may be used to detect high risk donors rather than detection of syphilis when stored blood is used. HBsAg and HIV tests should be routinely done on every unit of blood and anti HCV tests should be done regularly, if possible.

High prevalence of HBV infectivity in blood donors detected by the dot blot hybridisation assay.

Hepatitis B virus (HBV) continues to be a significant cause for post-transfusion hepatitis in India, in spite of the introduction of compulsory hepatitis B surface antigen (HBsAg) screening. To understand the true HBV-infective pool in the blood donor population, HBV DNA was detected by a 32P-labelled dot blot hybridisation assay in 605 donor units that were negative for HBsAg by a third-generation Elisa. Serum alanine aminotransferase (ALT) was estimated in all these samples and correlated with DNA positivity. The frequency of HBV DNA positivity in HBsAg-negative units was very high (9.91%) and correlated well with the elevation in ALT (p < 0.00005). However, the frequency of elevated ALT was high (11.9%), using the locally determined upper limit of normal, and half of the DNA-positive samples had a normal ALT. Thus, ALT is a poor surrogate marker for HBV infectivity and efforts should be made to apply DNA detection systems in blood banks.