COVID-19 in a Portuguese whole blood donor population

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), leading to pneumonia and acute respiratory distress syndrome. The COVID-19 pandemic had a major impact on the stock of blood banks worldwide. This study aims to assess the prevalence of COVID-19 in a population of whole blood donors and analyze the possible association between blood group and susceptibility to the disease and the impact of adopting preventive measures against SARS-CoV-2 infection. Material and methods: This retrospective study included all whole blood donors from a Portuguese hospital between July and September 2021. A self-assessment questionnaire was used to collect data on COVID-19 infection, vaccination, and preventive measures. Statistical analysis was performed using Chi-square and Mann-Whitney U tests. Results: The prevalence of COVID-19 in the donor population was 11.96% (n = 97), with only 2 cases of serious illness requiring hospitalization. No association was found between blood group and disease susceptibility. Older men were less likely to adopt preventive measures. The vaccination rate was high, with 84.26% of donors having received at least one dose of the vaccine. Seven donors declined COVID-19 vaccination. Preventive measures did not differ based on COVID-19 infection status or vaccination. Discussion: Although there was a higher frequency of COVID-19 in group A donors, the blood group was not associated with susceptibility to infection. The donor population consisted of young individuals without comorbidities, showing a COVID-19 prevalence like the general population and few severe cases. The high vaccination rate and adoption of preventive measures likely contributed to these findings.

Ingestive behavior of lambs confined in individual and group stalls

The experiment was conducted to evaluate the ingestive behavior of lambs confined in individual and group stalls. We used thirty-four lambs in their growing phase, aged an average of three months, with mean initial live weight of 17.8±5.2 kg. They were allotted in a completely randomized design with 24 animals kept in individual stalls and 10 animals confined as a group. The experiment lasted for a total of 74 days, and the first 14 days were dedicated to the animals’ adaption to the management, facilities and diets. The data collection period lasted 60 days, divided into three 20-d periods for the behavior evaluation. The animals were subjected to five days of visual observation during the experiment period, by the quantification of 24 h a day, with evaluations on the 15th day of each period and an interim evaluation consisting of two consecutive days on the 30th and 31st day of the experiment. The animals confined as a group consumed less (p<0.05) fiber. However, the animals confined individually spent less (p<0.05) time on feeding, rumination and chewing activities and longer in idleness. Therefore, the lower capacity of lambs confined in groups to select their food negatively affects their feeding behavior.

An Illustrative Case of Neurofibromatosis Type 1 and NF1 Microdeletion

We report on a patient with NF1 microdeletion and clinical manifestations that fulfill the diagnostic criteria for neurofibromatosis type 1 but also presenting features reminiscent of Proteus syndrome.

Leishmanolysin (gp63 metallopeptidase)-like activity extracellularly released byHerpetomonas samuelpessoai

In previous studies, we showed thatHerpetomonas samuelpessoaiproduced a large amount of a surface-located metallopeptidase that presented similar biochemical properties to that of gp63 fromLeishmaniaspp., which is a well-known virulence factor expressed by these digenetic parasites. The present study aims to identify the proteolytic activity released by livingH. samuelpessoaicells. In this context, the parasites were incubated in phosphate buffer up to 4 h, and the supernatants were obtained by centrifugation and filtration steps and were then applied on SDS–PAGE to determine the secretory protein profile and on gelatin-SDS–PAGE to identify the proteolytic activity. The results demonstrated thatH. samuelpessoaisecreted at least 12 polypeptides and an extracellular peptidase of 66 kDa. This enzyme had its activity diminished by 1,10-phenanthroline, EDTA and EGTA. This metallopeptidase was active in a broad spectrum of pH, showing maximum activity at pH 6·0 at 37 °C. Casein was also cleaved by this secretory proteolytic enzyme, while bovine serum albumin and haemoglobin were not degraded under these conditions. Fluorescence microscopy and flow cytometry using anti-gp63 antibody against leishmanolysin ofL. amazonensisdemonstrated the presence of similar molecules on the cell-surface ofH. samuelpessoai. Moreover, immunoblot analysis showed the presence of a reactive polypeptide in the cellular extract and in the supernatant fluid ofH. samuelpessoai, which suggests immunological similarities between these two distinct trypanosomatids. The zinc-metallopeptidase inhibitor 1,10-phenanthroline was able to inhibit the secretion of the 66 kDa metallopeptidase in a dose-dependent manner, while the phospholipase C inhibitor (p-CMPS) did not alter the secretion pattern. Additionally, anti-cross-reacting determinant (CRD) antibody failed to recognize any secreted polypeptide fromH. samuelpessoai. Collectively, these results suggest that the gp63-like molecule was released from theH. samuelpessoaisurface by proteolysis instead of phospholipolysis, in a similar mechanism to that observed inLeishmania.

Mathematical modeling of controlled-release kinetics of herbicides in a dynamic-water-bath system

Release of herbicides from lignin-based formulations follows a diffusion-controlled mechanism. For mathematical modeling of diffusive transport, the conventional approach is to assume sink conditions at both surfaces of polymeric matrix. This boundary condition proved to be inadequate to describe experimental data obtained in a water dynamic bath system. However, satisfactory descriptions for this system were obtained when a stagnant unstirred layer of herbicide solution was used as the boundary condition. The adequacy of the model incorporating this new boundary condition was statistically tested using the Fisher test at a confidence level of 95% and plotting the residual distribution.

Neonatal handling and the expression of immunoreactivity to tyrosine hydroxylase in the hypothalamus of adult male rats

Neonatal handling has long-lasting effects on behavior and stress reactivity. The purpose of the present study was to investigate the effect of neonatal handling on the number of dopaminergic neurons in the hypothalamic nuclei of adult male rats as part of a series of studies that could explain the long-lasting effects of neonatal stimulation. Two groups of Wistar rats were studied: nonhandled (pups were left undisturbed, control) and handled (pups were handled for 1 min once a day during the first 10 days of life). At 75-80 days, the males were anesthetized and the brains were processed for immunohistochemistry. An anti-tyrosine hydroxylase antibody and the avidin-biotin-peroxidase method were used. Tyrosine hydroxylase-immunoreactive (TH-IR) neurons were counted bilaterally in the arcuate, paraventricular and periventricular nuclei of the hypothalamus in 30-microm sections at 120-microm intervals. Neonatal handling did not change the number of TH-IR neurons in the arcuate (1021 +/- 206, N = 6; 1020 +/- 150, N = 6; nonhandled and handled, respectively), paraventricular (584 +/- 85, N = 8; 682 +/- 62, N = 9) or periventricular (743 +/- 118, N = 7; 990 +/- 158, N = 7) nuclei of the hypothalamus. The absence of an effect on the number of dopaminergic cells in the hypothalamus indicates that the reduction in the amount of neurons induced by neonatal handling, as shown by other studies, is not a general phenomenon in the brain.

Mathematical modeling of controlled-release systems of herbicides using lignins as matrices. A review

The herbicides applied in soils can be easily lost, owing to leaching, volatilization, and bio- and photodegradation. Controlled-release systems using polymeric matrices claim to solve these problems. The movement of the herbicides in the soil is also an important phenomenon to be studied in order to evaluate the loss processes. The development of mathematical models is a relevant requirement for simulation and optimization of such systems. This study reviews mathematical models as an initial step for modeling data obtained for controlled-release systems of herbicides (diuron, 2,4-dichlorophenoxyacetic acid, and ametryn) using sugarcane bagasse lignin as a polymeric matrix. The release kinetic studies were carried out using several acceptor systems including a water bath, soil, and soil-packed columns. Generally, these models take into account phenomena such as unsteady-state mass transfer by diffusion (Fick's law) and convection, consumption by several processes, and partitioning processes, resulting in partial differential equations with respect to time and space variables.

A comparative study of lymph node mast cell populations in five marsupial species

In order to determine whether different subpopulations of mast cells exist, mast cells of mandibular and axillary lymph nodes from five species (Didelphis aurita, Metachirus nudicaudatus, Philander opossum, Marmosops incanus and Gracilinanus agilis) of South American marsupials were studied. Our results showed that mast cells present in the connective tissue of the capsule and septa (CTMC) were similar to those described for eutherian mammals. However, a population of mast cells that was present in the lymphatic sinuses and bathed by the lymph, plus in direct contact with granulocytes, lymphocytes, macrophages, and reticular cells, were morphologically and histochemically different from the CTMC. In the five species studied, these cellular types, called lymphatic-sinus mast cells (LSMC), had a lower concentration of intragranular heparin and, in four of the five species, the cytoplasmic granules appeared to be larger than those in CTMC. Although LSMC have been rarely described in eutherian mammals, it was verified, in this study, that LSMC are nevertheless present in lymphatic sinuses of the five metatherian species studied. These observations suggest that the presence of LSMC may be a characteristic of the marsupials and important in the immune response and adaptive success of the Didelphidae.

[Etiological and clinical characteristics of infectious optic neuritis]

Fifty-one patients with infectious optic neuritis (ION) with no associated choroidal or retinal involvement were studied in relation to the etiologic agents, and to the epidemiological and clinical features to look up features which could be used to distinct them from the demyelinating optic neuritis (DON) which have a well-known tendency to convert to multiple sclerosis. Bilateral involvement was found in 23 patients (45.1%), simultaneously in 18 cases. Sex distribution was 2M:1F. The ages ranged from 1 to 82 years (median 34.8); 1/3 of the patients were younger than 20 and 1/3 were 50 years of age or older. Syphilis was found in 19 patients being the single most common etiology, whereas viral infections were found in 41.2% of the cases. Visual acuity was severely damaged in most patients and was worse than 20/200 in 57.3% of the involved eyes. Color vision was affected in 91.8%. Visual field defects were found in 92.2%, with predominance of the central defects (40.7%). The optic disc was abnormal in 90.5% of the eyes. This study clearly demonstrates that ION and DON have distinct epidemiological and clinical features. The awareness of these differences may help clinicians to follow different paths for the correct diagnosis and appropriate treatment and prognostic orientation of their patients.