Amorphous Drug-Polymer Salts: Maximizing Proton Transfer to Enhance Stability and Release.

An amorphous drug-polymer salt (ADPS) can be remarkably stable against crystallization at high temperature and humidity (e.g., 40°C/75% RH) and provide fast release. Here, we report that process conditions strongly influence the degree of proton transfer (salt formation) between a drug and a polymer and in turn the product's stability and release. For lumefantrine (LMF) formulated with poly(acrylic acid) (PAA), we first show that the amorphous materials prepared by slurry conversion and antisolvent precipitation produce a single trend in which the degree of drug protonation increases with PAA concentration from 0% for pure LMF to ∼100% above 70 wt % PAA, independent of PAA's molecular weight (1.8, 450, and 4000 kg/mol). This profile describes the equilibrium for salt formation and can be modeled as a chemical equilibrium in which the basic molecules compete for the acidic groups on the polymer chain. Relative to this equilibrium, the literature methods of hot-melt extrusion (HME) and rotary evaporation (RE) reached much lower degrees of salt formation. For example, at 40 wt % drug loading, HME reached 5% salt formation and RE 15%, both well below the equilibrium value of 85%. This is noteworthy given the common use of HME and RE in manufacturing amorphous formulations, indicating a need for careful control of process conditions to ensure the full interaction between the drug and the polymer. This need arises due to the low mobility of macromolecules and the mutual hindrance of adjacent reaction sites. We find that a high degree of salt formation enhances drug stability and release. For example, at 50% drug loading, an HME-like formulation with 19% salt formation crystallized faster and released only 20% of the drug relative to a slurry-prepared formulation with 70% salt formation. Based on this work, we recommend slurry conversion as the method for preparing ADPS for its ability to enhance salt formation and continuously adjust drug loading. While this work focused on salt formation, the impact of process conditions on the molecular-level interactions between a drug and a polymer is likely a general issue for amorphous solid dispersions, with consequences on product stability and drug release.

Amorphous Drug-Polymer Salt with High Stability under Tropical Conditions and Fast Dissolution: The Case of Clofazimine and Poly(acrylic acid).

We report that the stability of amorphous clofazimine (CFZ) against crystallization is vastly improved by salt formation with a polymer without sacrificing dissolution rate. A simple slurry method was used to produce the amorphous salt of CFZ with poly(acrylic acid) (PAA) at 75 wt % drug loading. The synthesis was performed under a mild condition suitable for thermally unstable drugs and polymers. Salt formation was confirmed by visible spectroscopy and glass temperature elevation. The amorphous salt at 75 wt % drug loading is remarkably stable against crystallization at 40 °C and 75% RH for at least 180 days. In contrast, the amorphous solid dispersion containing the un-ionized CFZ dispersed in poly(vinylpyrrolidone) crystallized in 1 week under the same condition. The high stability of the amorphous drug-polymer salt is a result of the absence of a drug-polymer crystalline structure, reduced driving force for crystallizing the free base, and reduced molecular mobility. Despite the elevated stability, the amorphous drug-polymer salt showed fast dissolution and high solution concentration in two biorelevant media (SGF and FaSSIF). Additionally, the amorphous CFZ-PAA salt has improved tabletability and powder flow relative to crystalline CFZ. The CFZ-PAA example suggests a general method to prepare amorphous drugs with high physical stability under tropical conditions and fast dissolution.

Hospital wastewaters: A reservoir and source of clinically relevant bacteria and antibiotic resistant genes dissemination in urban river under tropical conditions.

The occurrence and dissemination of antibiotic resistant genes (ARGs) that are associated with clinical pathogens and the evaluation of associated risks are still under-investigated in developing countries under tropical conditions. In this context, cultivable and molecular approaches were performed to assess the dissemination of bacteria and the antibiotic resistance genes in aquatic environment in Kinshasa, Democratic Republic of the Congo. Cultivable approach quantified ß-lactam, carbapenem resistant, and total Escherichia coli and Enterobacteriaceae in river sediments and surface waters that receive raw hospital effluents. The molecular approach utilized Quantitative Polymerase Chain Reaction (qPCR) to quantify the total bacteria and the richness of relevant bacteria (Escherichia coli, Enterococcus, and Pseudomonas), and antibiotic resistance genes (ARGs: blaOXA-48, blaCTX-M, blaIMP, blaTEM) in sediment samples. Statistical analysis were employed to highlight the significance of hospital contribution and seasonal variation of bacteria and ARGs into aquatic ecosystems in suburban municipalities of Kinshasa, Democratic Republic of the Congo. The contribution of hospitals to antibiotic resistance proliferation is higher in the dry season than during the wet season (p < 0.05). Hospital similarly contributed Escherichia coli, Enterococcus, and Pseudomonas and ARGs significantly to the sediments in both seasons (p < 0.05). The organic matter content correlated positively with E. coli (r = 0.50, p < 0.05). The total bacterial load correlated with Enterococcus, and Pseudomonas (0.49 < r < 0.69, p < 0.05). Each ARG correlated with the total bacterial load or at least one relevant bacteria (0.41 < r < 0.81, p < 0.05). Our findings confirm that hospital wastewaters contributed significantly to antibiotic resistance profile and the significance of this contribution increased in the dry season. Moreover, our analysis highlights this risk from untreated hospital wastewaters in developing countries, which presents a great threat to public health.

Infrared thermography for evaluation of the environmental thermal comfort for livestock.

The objective of this study was to assess the use of infrared thermography as a microclimate-evaluating tool and an estimate of the thermal comfort provided by four types of tree to cattle under grazing conditions in the central region of Brazil. The experiment was conducted at the Embrapa Beef Cattle Company, in Campo Grande, MS, Brazil, from June to August 2015. Evaluations were carried out over four consecutive days, at 1-hour intervals, from 8:00 a.m. to 4:00 p.m. (local time; GMT - 4:00). Infrared thermography images of tree crowns and soil surface underneath them from the shadow projection of four tree species native to the Brazilian cerrado (savannah-like) biome were obtained. The microclimate was assessed by estimation of thermal indices: temperature and humidity index, black globe, and radiation thermal load. The previous was calculated based on records of air temperature, dew point temperature, black globe temperature, air relative humidity, wind speed, and solar radiation. The geometrical settings of the trees were assessed for each tree component. Five thematic groups were formed based on multiple factor analysis that summarizes three synthetic analytical dimensions to explain the total variance among the studied elements and the existing correlations between groups. Positive linear correlations were found between thermography and the temperature measurements, thermal comfort indices, and radiation, suggesting that infrared thermography can be used as a tool for estimating and monitoring the microclimate and thermal comfort, presenting a potential use of measurement in agroforestry systems.

The dynamic adaptation of Brazilian Brahman bulls.

Heat stress is one of the most important factors that affect the performance of some Bos taurus breeds and crosses in tropical regions. The Brahman breed was developed in hot regions of the world and often has genes that confer resistance to heat stress compared to other breeds of beef cattle. The goal of this work was to evaluate the adaptive responses of Brahman bulls, based on physiological, hormonal and hair characteristics according to season. The physiological, hormonal and hair characteristics were rectal temperature (RT), respiratory rate (RR), sweating rate (SR), triiodothyronine (T3), thyroxine (T4), cortisol concentrations (CO), coat thickness (CT), hair length (HL), hair diameter (HD) and hair density (ND). These were recorded in Brahman bulls from a Cerrado biome during four seasons: spring (21 September to 20 December), summer (21 December to 17 March), autumn (18 March to 20 June) and winter (21 June to 20 September). Data was analyzed using a general linear model that included season as a fixed effect; in addition, multivariate tests and logistic regression were also used to characterize the animals within each season. The meteorological variables defined the four seasons, besides identifying climatic differences between them. Significant differences (P > 0.05) were found for most of the physiological, hormonal and hair characteristics according to season. The Brahman bulls presented particular adaptive characteristics in each season. Individually, most of the Brahman bulls presented the same adaptive reaction in each season; particular similarity occurred for the summer and autumn. This pattern is a reflection of the inter-relationships between physiological responses and hair characteristics.

Prevalence of water-related diseases and groundwater (drinking-water) contamination in the suburban municipality of Mont Ngafula, Kinshasa (Democratic Republic of the Congo).

An epidemiological survey conducted among users of water points and medical institutions in the N'djili Kilambu neighborhood of Kinshasa in Democratic Republic of the Congo, indicates that waterborne diseases have already affected more than 60% of the patients admitted to local clinics between 2013 and 2017. In order to raise public and political awareness about this hazardous health issue resulting from the lack of safely managed sanitation systems, this study investigates the microbial quality of drinking water from local water resources. Water samples were collected from nine wells and streams used as drinking sources, and analyzed for Fecal Indicator Bacteria (FIB), including Escherichia coli, Enterococcus, and Total Coliforms. Physicochemical parameters (pH, electrical conductivity, O2, and soluble ions (Na+, K+, PO43-, SO42-, NO3-, NO2-) were also analyzed. Except for NO3- and NO2-, the average concentrations of the physicochemical parameters and dissolved ions generally meet the guidelines for drinking/domestic water quality. By contrast, the results reveal high levels of FIB in the water samples collected during both dry and wet seasons. The contamination is significantly higher during the wet season compared to dry season, due to increased runoff, open defecation practices, and more frequent overflow of onsite sanitation systems and septic tanks.

Response of saliva Na/K ratio to changing Na supply of lactating cows under tropical conditions.

BACKGROUND: Factorial determination of the sodium (Na) requirement of heat-stressed lactating cows is hindered by accurate estimates of the Na losses through sweat. Direct studies, therefore, may be needed requiring information on the time course of healthy animals to become Na depleted and the subsequent rate of repletion. The rate of Na depletion and subsequent rate of Na repletion with two levels of dietary Na to lactating dairy cows housed under tropical conditions were investigated using the salivary Na/K. RESULTS: The 12 lactating cows (salivary Na/K ratio 14.6) rapidly developed clinical signs of Na deficiency, including pica, polyuria and polydipsia, reduced body weight and reduced milk yield when fed a low-Na ration (0.33 g kg-1 dry matter (DM)) for 3 weeks. Deficiency symptoms were associated with a rapid decrease in salivary Na/K ratio to <4.3 from 7 to 21 days. Subsequent repletion of the cows with NaCl to a ration concentration of 1.1 or 1.6 g Na kg-1 DM for 5 weeks did not restore salivary Na/K ratio to values of >6. CONCLUSION: A daily Na intake of heat-stressed lactating cows to a ration intake of 1.6 g Na kg-1 DM was insufficient to restore Na deficiency. One week was sufficient to deplete heat-stressed lactating cows of Na, allowing for rapid dose-response studies utilizing the salivary Na/K ratio as a parameter for Na status of cows under tropical conditions. © 2016 Society of Chemical Industry.

Realistic exposure to fipronil, 2,4-D, vinasse and their mixtures impair larval amphibian physiology.

Expansion of sugarcane crops may have contributed to the increased contamination of native habitats in Brazil. Several species of amphibians inhabit ponds formed in flooded farmlands, where pesticide concentrations are usually high. This study evaluated the ecotoxicological effects of the sugarcane pesticides fipronil and 2,4-D, as well as the fertilizer vinasse (isolated and mixed), on physiological responses of Leptodactylus fuscus and Lithobates catesbeianus tadpoles. In situ assays were conducted in mesocosms with concentrations based on the doses recommended by the manufacturer. Vinasse (1.3% dilution) caused 100% tadpoles' mortality immediately after its application. Fipronil and/or 2,4-D altered antioxidant and biotransformation responses, induced neurotoxicity and changed lipid contents in tadpoles. A multivariate approach indicated that the mixture of pesticides induced most of the sublethal effects in both tadpole species, in addition to the isolated fipronil in L. fuscus. Fipronil alone increased glucose-6-phosphate dehydrogenase (G6PDH) activity, decreased acetylcholinesterase (AChE) and total lipid contents, and altered some individual lipid classes (e.g., free fatty acids and acetone-mobile polar lipids) in L. fuscus. The interaction between fipronil and 2,4-D in this species were more evident for lipid contents, although enzymatic alterations in G6PDH, AChE and glutathione-S-transferase (GST) were also observed. In L. catesbeianus, the mixture of pesticides reduced triglycerides and total lipids, as well as increased GST and decreased AChE activities. The detoxifying enzyme carboxylesterase was reduced by 2,4-D (alone or in mixture) in both species. Isolated pesticides also modulated specific lipid classes, suggesting their disruptive action on energy metabolism of tadpoles. Our study showed that fipronil, 2,4-D, and vinasse, individually or mixed, can be harmful to amphibians during their larval phase, causing mortality or impairing their functional responses.

Frequency of sheep farms with anthelmintic resistant gastrointestinal nematodes in the Mexican Yucatán peninsula.

The present study explored the frequency of hair-sheep farms with gastrointestinal nematodes (GIN) resistant to albendazole sulfoxide (AS), ivermectin (IVM) and levamisole (LEV) in the Yucatán peninsula, México, using the faecal egg count reduction test (FECRT), and compared the frequency of farms diagnosed with resistance using three different formulae. The survey included farms from the states of Campeche (9) and Yucatán (14) (2016-2019). Collaborating farms had >100 grazing ewes. Animals in the FECRT were > 12 months old, received no anthelmintic for >8 weeks and had ≥150 GIN eggs per gramme of faeces (EPG). Animals were distributed to respective groups: untreated controls, AS (5 mg/kg BW), IVM (0.2 mg/kg BW), and LEV (7.5 mg/kg BW). Due to low EPG, some farms only included one or two AH groups. Second faecal samples were obtained on day 14 post-treatment to estimate the percentage reduction (%R) and 95% confidence interval (95%CI). Criteria to declare resistance were those proposed by the World Association for the Advancement of Veterinary Parasitology. Three formulae were used to estimate resistance frequency: The RESO© and eggCounts-T:C, which considered treated and control EPG means post-treatment, but differed in their 95%CI estimation, while the eggCounts-T:T only considered pre- and post-treatment EPG means with 95%CI. The RESO© and eggCounts-T:C formulae resulted in the same frequency of IVM resistant farms for Campeche (100%; 9/9) and Yucatán (92.9%; 13/14), while, the eggCount-T:T formula resulted in a frequency of 85.7% (12/14) IVM resistance in Yucatán. The three formulae estimated the same frequency of AS resistant farms in Campeche (100%; 9/9) and Yucatán (87.5%; 7/8). The RESO© and the eggCounts-T:C formulae resulted in the same frequency of LEV resistant farms for Campeche (44.4%; 4/9), and Yucatán (60.0%; 6/10), but the eggCounts-T:T formula resulted in a frequency of 40.0% (4/10) LEV resistance in Yucatán. The FECRT using RESO© or eggCounts-T:C formulae are stricter than the eggCounts-T:T as the latter cannot identify what proportion of the %R cannot be attributed to the AH. The untreated control group helped adjusting the %R calculation and seemed more adequate considering the propensity of hair-sheep to reduce their EPG on their own. .

Amorphous Drug-Polymer Salts.

Amorphous formulations provide a general approach to improving the solubility and bioavailability of drugs. Amorphous medicines for global health should resist crystallization under the stressful tropical conditions (high temperature and humidity) and often require high drug loading. We discuss the recent progress in employing drug-polymer salts to meet these goals. Through local salt formation, an ultra-thin polyelectrolyte coating can form on the surface of amorphous drugs, immobilizing interfacial molecules and inhibiting fast crystal growth at the surface. The coated particles show improved wetting and dissolution. By forming an amorphous drug-polymer salt throughout the bulk, stability can be vastly enhanced against crystallization under tropical conditions without sacrificing the dissolution rate. Examples of these approaches are given, along with suggestions for future work.

Monitoring chemical compositional changes of simulated spilled Brazilian oils under tropical climate conditions by multiple analytical techniques.

To comprehensively understand the chemical changes over time of spilled oils subject to tropical climate conditions and the active weathering processes, a spill simulation experiment was conducted along 210 days with two distinct Brazilian oils (19 and 24 API) under irradiation and non-irradiation of sunlight. Isoprenoids and n-alkanes showed a great loss after 40 days for both oils under the two conditions due to evaporation. Diagnostic ratios of saturated biomarkers showed no changes, whereas the polycyclic aromatic hydrocarbons had a decreasing concentration under both conditions mainly due to evaporation. Furthermore, oxygenated polar compounds produced by photooxidation were investigated by ESI(-) FT-ICR MS and showed changes only for the oils exposed to sunlight irradiation. Based on the observed polar compositional changes, new parameters are suggested using heteroatom classes to estimate oil spill time under tropical conditions: NO3/NO2; NO3/(NO + NO2); ∑NOx/N1; (O4 + O3)/(O2 + O1); O4/(O2 + O1); and O3/O2.

Amorphous Drug-Polymer Salt with High Stability under Tropical Conditions and Fast Dissolution: The Challenging Case of Lumefantrine-PAA.

Lumefantrine (LMF), a high-mobility and easy-to-crystallize WHO drug for treating malaria, can form an amorphous salt with poly(acrylic acid) (PAA) that is remarkably stable against crystallization at high humidity and temperature and has fast dissolution rate. The amorphous salt up to 75% drug loading was synthesized under a mild slurry condition easily implemented in basic facilities for global health. Salt formation was confirmed by IR spectroscopy and the much elevated glass transition temperature. At 50% drug loading, the amorphous salt resists crystallization for at least 18 months under the highly stressful condition of 40 °C and 75% RH. In contrast, the dispersion containing neutral LMF in PVP fully crystallized in 4 d and the dispersion in HPMCAS, a weak polyelectrolyte of lower charge density than PAA, crystallized by 50% in 7 d. The amorphous salt at 50% drug loading showed much faster dissolution than crystalline LMF: In SGF, the area under the curve (AUC) was 30 times larger within the gastric emptying time (4 h); in FaSSIF, the enhancement was even larger - by 200 times. Nanodroplets were detected during the dissolution in SGF, possibly accounting for the apparent enhancement of dissolution rate. The LMF-PAA example as a challenging case, along with the previously reported clofazimine-PAA, demonstrates the general utility of amorphous drug-polymer salts to achieve high stability under tropical conditions and enhanced dissolution and bioavailability.

Sequential feeding with high-fat/low-crude protein diets for two lines of growing-finishing pigs under daily cyclic high ambient temperature conditions1.

This study was conducted to evaluate the effects of sequential feeding technique in two genetic lines (GL; Line A [cross having a greater proportion of Pietrain] and Line B [cross having a lower proportion of Pietrain]) of growing-finishing pigs reared under daily cyclic high ambient temperature conditions. Seventy-eight castrated male pigs (22 ± 2.5 kg BW) were housed in a single group and were allocated to one of the three feeding programs: control (CON, 24 h control diet), high-fat/low-crude protein (HF/LP, 24 h high-fat/low-crude protein diet), and sequential feeding (SEQ, control diet from 1800 to 1000 h and HF/LP diet from 1001 to 1759 h). Cyclic high ambient temperature was induced by exposing the pigs to 22ºC ambient temperature from 1800 to 1000 h (time-period 22ºC, TP22) and to 30ºC from 1001 to 1759 h (TP30). The experimental period lasted 84 days and was divided into 3 growth phases, growing 1 (from day 0 to 20), growing 2 (from day 21 to 48) and finishing (from day 49 to 83). Feed intake was recorded in real time using an automatic feeder system. Pigs were weighed at the beginning and end of each experimental phase. Animal body composition was measured through dual-energy X-ray absorptiometry on days 0, 35, and 70. The ambient temperature averaged 22.3 ± 0.4ºC during TP22 and 30.2 ± 0.5ºC during TP30, characterizing the condition of daily ambient temperature variation that which pigs are usually exposed in tropical climate areas. During growing phase 1, the feeding programs had negligible effects on pig performance (P > 0.05), whereas during growing phase 2, ADG was greater in SEQ than in CON pigs (7%; P = 0.04). During the finishing phase, HF/LP pigs had greater ADFI (+ 10%) and ADG (+ 8%) than CON pigs. Lean mass and gain did not differ among feeding programs (P > 0.05). Overall, fat mass and gain were similar between SEQ and HF/LP pigs (P > 0.05), and both were greater than those of CON pigs (P < 0.05). On the basis of pig performance per phase, the supply of high-fat/low-crude protein diets (SEQ and HF/LP feeding) improved the performance of pigs under daily cyclic high ambient temperature. However, the use of these techniques resulted in fatter carcasses and in higher energy cost of gain. Finally, pigs with greater proportion of Pietrain genes had decreased growth performance in our experimental conditions.

Dietary cation and anion difference: Effects on milk production and body fluid distribution in lactating dairy goats under tropical conditions.

This study aimed to determine the effect of dietary cation and anion difference (DCAD) on milk production and body fluid distribution in lactating dairy goats. Ten dairy goats were selected and divided into two groups, five animals each. Animals received either control DCAD (control, 22.81 mEq/100 g dry matter (DM)) or high DCAD (DCAD, 39.08 mEq/100 g DM). The results indicated that rectal temperature (Tr), respiration rate, milk yield and compositions did not differ between groups. But the percentage change of Tr from the DCAD group was lower than the control group between 09.00 and 13.00 hours. DM intake tended to increase in the DCAD group. Dairy goats in the DCAD group drank more water, but urinary excretion and plasma antidiuretic hormone concentration remained unchanged. Apparent water balance was higher from the DCAD group over 24 h. There was no effect of DCAD on plasma and blood volumes, but tended to increase in extracellular fluid and thereby increased total body water. The present results indicate that animals supplemented with high DCAD increase their total body water and apparent water balance. These results have contributed to the process of adaptation for evaporative cooling and would be useful in slowing down the elevation in Tr.

Accumulation of toxic metals and organic micro-pollutants in sediments from tropical urban rivers, Kinshasa, Democratic Republic of the Congo.

The increasing contamination of fresh water resource by toxic metals and Persistence Organic Pollutants (POPs) is a major environmental concern globally. In the present investigation, surface sediments collected from three main rivers named, Makelele, Kalamu and Nsanga, draining through the city of Kinshasa, Democratic Republic of the Congo, were characterized for grain size, organic matter, toxic metals, POPs (including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs)), and polycyclic aromatic hydrocarbons (PAHs). Furthermore, enrichment factor (EF) and geoaccumulation index (Igeo) were performed to determine metal source and pollution status. The results highlighted high concentration of toxic metals in all sediment samples, reaching the values (mg kg-1) of 325 (Cu), 549 (Zn), 165 (Pb) and 1.5 (Cd). High values of PCBs and OCPs were detected in sediment samples, e.g. in Makelele river, PCB values ranged from 0.9 to 10.9 with total PCBs (∑7 PCBs × 4.3): 169.3 µg kg-1; OCPs from 21.6 to 146.8 with ∑OCPs: 270.6 µg kg-1. The PBDEs concentrations were higher in investigated rivers comparatively with values detected in many rivers from Sub-Saharan Africa. The ΣPAHs value ranged from 22.6 to 1011.9 µg kg-1. River contamination may be explained by local intense domestic activities, urban and agricultural runoff, industrial and hospital wastewaters discharge into the rivers without prior treatment. This research provides not only a first baseline information on the extent of contamination in this tropical ecosystem but also represents useful tools incorporated to evaluate sediment quality in the river receiving systems which can be applied to similar aquatic environments.

Leachates draining from controlled municipal solid waste landfill: Detailed geochemical characterization and toxicity tests.

Management of municipal solid wastes in many countries consists of waste disposal into landfill without treatment or selective collection of solid waste fractions including plastics, paper, glass, metals, electronic waste, and organic fraction leading to the unsolved problem of contamination of numerous ecosystems such as air, soil, surface, and ground water. Knowledge of leachate composition is critical in risk assessment of long-term impact of landfills on human health and the environment as well as for prevention of negative outcomes. The research presented in this paper investigates the seasonal variation of draining leachate composition and resulting toxicity as well as the contamination status of soil/sediment from lagoon basins receiving leachates from landfill in Mpasa, a suburb of Kinshasa in the Democratic Republic of the Congo. Samples were collected during the dry and rainy seasons and analyzed for pH, electrical conductivity, dissolved oxygen, soluble ions, toxic metals, and were then subjected to toxicity tests. Results highlight the significant seasonal difference in leachate physicochemical composition. Affected soil/sediment showed higher values for toxic metals than leachates, indicating the possibility of using lagoon system for the purification of landfill leachates, especially for organic matter and heavy metal sedimentation. However, the ecotoxicity tests demonstrated that leachates are still a significant source of toxicity for terrestrial and benthic organisms. Therefore, landfill leachates should not be discarded into the environment (soil or surface water) without prior treatment. Interest in the use of macrophytes in lagoon system is growing and toxic metal retention in lagoon basin receiving systems needs to be fully investigated in the future. This study presents useful tools for evaluating landfill leachate quality and risk in lagoon systems which can be applied to similar environmental compartments.

Hospital Effluents Are One of Several Sources of Metal, Antibiotic Resistance Genes, and Bacterial Markers Disseminated in Sub-Saharan Urban Rivers.

Data concerning the occurrence of emerging biological contaminants such as antibiotic resistance genes (ARGs) and fecal indicator bacteria (FIB) in aquatic environments in Sub-Saharan African countries is limited. On the other hand, antibiotic resistance remains a worldwide problem which may pose serious potential risks to human and animal health. Consequently, there is a growing number of reports concerning the prevalence and dissemination of these contaminants into various environmental compartments. Sediments provide the opportunity to reconstruct the pollution history and evaluate impacts so this study investigates the abundance and distribution of toxic metals, FIB, and ARGs released from hospital effluent wastewaters and their presence in river sediments receiving systems. ARGs (bla TEM, bla CTX-M, bla SHV, and aadA), total bacterial load, and selected bacterial species FIB [Escherichia coli, Enterococcus (ENT)] and species (Psd) were quantified by targeting species specific genes using quantitative PCR (qPCR) in total DNA extracted from the sediments recovered from 4 hospital outlet pipes (HOP) and their river receiving systems in the City of Kinshasa in the Democratic Republic of the Congo. The results highlight the great concentration of toxic metals in HOP, reaching the values (in mg kg(-1)) of 47.9 (Cr), 213.6 (Cu), 1434.4 (Zn), 2.6 (Cd), 281.5 (Pb), and 13.6 (Hg). The results also highlight the highest (P < 0.05) values of 16S rRNA, FIB, and ARGs copy numbers in all sampling sites including upstream (control site), discharge point, and downstream of receiving rivers, indicating that the hospital effluent water is not an exclusive source of the biological contaminants entering the urban rivers. Significant correlation were observed between (i) all analyzed ARGs and total bacterial load (16S rRNA) 0.51 to 0.72 (p < 0.001, n = 65); (ii) ARGs (except bla TEM) and FIB and Psd 0.57 < r < 0.82 (p < 0.001, n = 65); and (iii) ARGs (except bla TEM) and toxic metals (Cd, Cr, Cu, and Zn) 0.44 to 0.72, (p < 0.001, n = 65). These findings demonstrate that several sources including hospital and urban wastewaters contribute to the spread of toxic metals and biological emerging contaminants in aquatic ecosystems.

Reproducción de conejos bajo condiciones tropicales, efectos negativos y posibles soluciones / Reproduction of rabbits under tropical conditions, negative effects and possible solutions

RESUMEN La fisiología digestiva y capacidad reproductiva hacen del conejo una especie con potencial para la producción de carne. En clima templado, su adecuado manejo reproductivo permite obtener entre 6 y 10 partos anuales con camadas de 6 y hasta 12 gazapos. En zonas tropicales, el estrés calórico disminuye su capacidad reproductiva. Las hembras presentan un incremento en la secreción de corticosteroides, modificando la secreción de la hormona liberadora de gonadotropina (GnRH), la hormona estimulante del folículo (FSH) y la hormona luteinizante (LH), disminuyendo el crecimiento y desarrollo folicular, calidad de ovocitos y la ovulación, y con ello el número de partos y tamaño de camada. En los machos se afecta la libido y la capacidad de monta. En la calidad seminal, disminuye 7.8 % el volumen, 7.7 % la concentración, 1.7 % la morfología y 5.5 % la motilidad. El objetivo del presente trabajo fue describir las estrategias utilizadas para disminuir el estrés calórico, que incluyó regular la temperatura en las instalaciones, suplementos alimenticios, cruzamiento de razas locales con razas mejoradas, desarrollo de líneas genéticas para climas tropicales, implementación de biotecnologías reproductivas como la inseminación artificial o criopreservación de semen, mejorando el comportamiento reproductivo del conejo bajo condiciones tropicales.

ABSTRACT The digestive physiology and reproductive capacity of the rabbit make it a species with potential for meat production. In a temperate climate, its adequate reproductive management allows to obtain between 6 and 10 annual litters per female with 6 up to 12 kits per litter. In tropical areas, heat stress alters metabolism and hormonal function, decreasing their reproductive capacity. In females, the main changes include an increase in the secretion of corticosteroids, modifying the secretion of gonadotropinreleasing hormone (GnRH), stimulating follicle hormone (FSH) and luteinizing hormone (LH), decreasing the growth and follicular development, oocyte quality and ovulation, and with it the number of births and size of litter. In males, libido and ability to mate are affected. In the seminal quality, a decrease of 7.8 % in volume, 7.7 % in concentration, 1.7 % in morphology and 5.5 % in motility is observed. The objective of the present work was to describe the strategies used to reduce the caloric stress. These included regulating the temperature in the facilities, supplementary food, crossing of local breeds with improved breeds, development of genetic lines for tropical climates, implementation of reproductive biotechnologies such as artificial insemination or cryopreservation of semen, improving the reproductive behavior of the rabbit under tropical conditions.