Biogenic production of silver, zinc oxide, and cuprous oxide nanoparticles, and their impregnation into textiles with antiviral activity against SARS-CoV-2.

Nanotechnology is being used to fight off infections caused by viruses, and one of the most outstanding nanotechnological uses is the design of protective barriers made of textiles functionalized with antimicrobial agents, with the challenge of combating the SARS-CoV-2 virus, the causal agent of COVID-19. This research is framed within two fundamental aspects: the first one is linked to the proposal of new methods of biogenic synthesis of silver, cuprous oxide, and zinc oxide nanoparticles using organic extracts as reducing agents. The second one is the application of nanomaterials in the impregnation (functionalization) of textiles based on methods called "in situ" (within the synthesis), and "post-synthesis" (after the synthesis), with subsequent evaluation of their effectiveness in reducing the viral load of SARS-CoV-2. The results show that stable, monodisperse nanoparticles with defined geometry can be obtained. Likewise, the "in situ" impregnation method emerges as the best way to adhere nanoparticles. The results of viral load reduction show that 'in situ' textiles with Cu2O NP achieved a 99.79% load reduction of the SARS-CoV-2 virus.

Treatment with an intravaginal progestagen and estradiol to prevent prolonged anestrus in crossbred zebu cows under tropical conditions.

To study the effectiveness of a treatment with an intravaginal progestagen in combination with estradiol-17beta (E-17beta) on estrus induction, prevention of prolonged anestrus and fertility in noncycling crossbred zebu cows, a trial was conducted in a farm in Zulia state, Venezuela. Fifty noncycling suckled crossbred cows (B. taurus x B. indicus) with 60 dpp were randomly allotted to one of the following treatments: MAP+E-17beta (n=22), intravaginal device (250 mg of MAP) during 7 days + 50 mg of MAP and 5 mg of E-17beta im (day 0) and 1.5 mg of E-17beta im (day 8) (Pregnaheat-E; VIATECA-Venezuela); CG (n=28), control group without hormonal treatment. The MAP+E-17beta group showed higher (P<0.05) estrus and synchronization rates (59.1 and 36.4 %) than CG (25.0 and 3.5 %). Cows receiving MAP had higher (P<0.05) overall pregnancy rate than CG (45.5 and 17.8 %, respectively). A decreased (P<0.05) anestrus rate was observed in MAP+E-17beta (31.8%) compared to CG (57.1%). Calving-conception interval was shorter (P<0.05) in MAP+E-17beta (132.5+/-16.8 days) than in CG (178.9+/-14.7 days). In conclusion, treatment with MAP+E-17beta at 60 days postpartum was effective to induce estrus, prevent prolonged anestrus, and reduce the calving-conception interval, improving reproductive performance in dual purpose crossbred Zebu cows.

Serological evidence of Neospora caninum in dual-purpose cattle herds in Venezuela.

Bovine neosporosis is a parasitic disease produced by Neospora caninum that induces abortion in cows, and consequently has a negative impact on the herd's reproductive efficiency. The main objective of this research was to determine the serological evidence of N. caninum in cattle herds from Venezuela using an indirect antibody capture ELISA test. Four hundred and fifty-nine (459) serum samples from crossbred adult cows were collected to be tested for Neospora antibodies. The sampled cows came from 15 large farms located in eight important cattle states that have predominant dual-purpose production systems (cattle from these farms are used for both milk and meat production). Fifty-two cows (11.3%) were seropositive to N. Caninum. Thirteen (86.7%) of 15 studied herds had cows seropositive to N. caninum. The average within-herd seroprevalence was 11.5% (range 3.8-36.7%). Cows that aborted in some of these farms had 2.71 (P: 0.009) greater odds to be seropositive when compared to cows that did not abort. Each one of the eight states represented in our study had seropositive animals. These results are the first evidence of exposure to N. caninum in Venezuelan cattle herds, indicating the possible circulation of this pathogen in the country. Further epidemiological studies should be granted to determine the spread of the disease in the Venezuelan cattle industry and its associated risk factors.

Social and breed effects on the expression of a PGF2alpha induced oestrus in beef cows.

Social organization and breed effects following PGF2alpha were studied in mature Angus, Brahman and Senepol cows allocated into two groups (each A = 5, B = 5 and S = 5). Variables including interval to oestrus onset (IEO), oestrous duration (DE), total mounts received (TMR), and oestrous intensity (IE) were derived via HeatWatch. Breed-type influenced IEO (B = 42.6 +/- 6.7 h; S = 54.6 +/- 6.0 h; and A = 27.8 +/- 5.8 h; p < 0.003). Within breeds, dominant B (69.4 +/- 13.3 h) and S (65.5 +/- 7.4 h) cows were slower (p < 0.05) to be detected in oestrus than subordinate (38.1 +/- 4.4 h) and intermediate (40.6 +/- 6.0 h). However, within A, dominant cows (16.4 +/- 12.5 h) were detected in oestrus earlier (p < 0.05) than intermediate (44.3 +/- 9.2 h) and subordinates (32.7 +/- 5.1 h). Angus (21.5 +/- 2.4 h) and B (22.1 +/- 3.0 h) cows had longer (p < 0.01) DE than S (9.1 +/- 2.8 h). Dominants (20.4 +/- 3.0) and intermediates (20.2 +/- 2.3 h) cows had longer DE (p < 0.04) than subordinates (12.1 +/- 2.1 h) although the interaction breed x social order showed that dominant S had shorter DE than dominant A and B (10.1 +/- 3.3; 34.8 +/- 6.0 h; and 20.0 +/- 6.4 h, respectively; p < 0.001). Angus cows had less TMR than B (p < 0.02) and tended to be less than S cows (p < 0.06). Overall, greatest (p < 0.008) IE occurred in the first 9 h after onset of oestrus with no breed effect (p > 0.05). Dominant cows tended (p < 0.10) to have less TMR (3.2 +/- 0.7 mounts) than subordinate (4.1 +/- 0.4 mounts) and intermediate (4.7 +/- 0.6 mounts) throughout, especially 3-6 h after oestrus onset (p < 0.07). Breed and social order both influence PGF2alpha-induced oestrus behaviour.

[Occupational exposure to lead in production units in Maracaibo, Venezuela]. / Exposición ocupacional a plomo en unidades productivas en Maracaibo, Venezuela.

A medical occupational study was performed in 40 workers belonging to productive units in telecommunication works, 22 to car radiator mechanics and 11 to battery repairs. A practical medical and occupational study was applied to the group and also were determined their blood lead and air lead exposure levels. Seventy-three individuals, without risk of laboral exposure to lead, without familiar, pathological and occupational antecedents, and healthy at the time of the test, to whom the blood lead levels were determined served as control group. The mean values of plumbemia in exposure workers to inorganic lead exceed the level threshold of the COVENIN 2277-85 norm (30 micrograms/dl) (Telecommunication work, 40.10 micrograms/dl, radiators mechanics, 37.40 micrograms/dl and battery repairs, 45.77 micrograms/dl), values that were significantly higher (p < 0.0001) compared with the ones obtained in the non-exposed population. The factors that can influence the variability of the results were analyzed and it was established a correlation between the plumbemia of the radiator mechanics and battery repairmen and the length of occupational period and air lead levels (p < 0.0001). The inherent factors to the climatic, occupational and personal conditions of technicians in telecommunications, are presented as elements able to explain the lack of correlation between blood lead levels and length of occupational period and air lead. The clinical findings in exposed workers were unspecific. The workers do not practice or follow the basic sanitary regulations, personal protection and industrial security. This work will contribute to establish a basic description, to further and more complex observational prospective studies in order to determine the occurrence of alterations that are derived from occupational lead exposure.

[Spirometry in workers in a wheat-processing industry]. / Espirometría en trabajadores de una industria procesadora de trigo.

In order to determine both clinical and spirometric changes due to high environmental concentrations of wheat dust at a wheat processing plant mill, 48 exposed men and 48 age and antroprometrically-matched, non-exposed apparently healthy men were studied. In both groups a medical and occupational history were taken, and spirometric measurements were carried out, that included Forced Vital Capacity (FVC), Forced Expiratory Volume at the first second (FEV1), Peak Flow Rate (PFR), Forced Percentual Expiratory Volume (FEV%), Forced Percentual Vital Capacity (FVC%), Forced Expiratory Flow at 25% (FEV25%), at 50% (FEV50%) and at 75% (FEV75%) of their Forced Vital Capacity, which were analyzed through Corzo's predictive equations and the lung deterioration's criteria by USA's Thoracic Association. The environmental wheat dust was determined by gravimetry and its concentration was higher than the legally admitted (3/5, 60%). There was a decrease in the PFR, FEV%, FEV25% and FEV75%. (p < 0.05). In addition, 4 restrictive and 1 obstructive syndrome were detected in the exposed workers and none in the control group. The spirometric values diminished in a positive correlation with the time of exposure and smoking habits. There was no correlation between the clinical findings and the dust concentration but it did exist with the spirometric values. It is concluded that in this plant, the wheat dust exposed workers have a diminished spirometric values.