Effect of carbohydrates on the adhesion of Bordetella bronchiseptica to the respiratory epithelium in rabbits.

This study proposes an ecological approach for preventing respiratory tract infections caused by Bordetella bronchiseptica in mammals using a mixture of carbohydrates. In an in vivo study, 51-day-old New Zealand rabbits were treated with a solution containing 1 × 107 CFUs of B. bronchiseptica and 250 µg of one of the following carbohydrates: N acetylglucosamine (GlcNAc), N acetylgalactosamine (GalNAc), alpha methyl mannose (AmeMan), alpha methyl glucose (AmeGlc) and sialic acid (Neu5AC). Positive (B. bronchiseptica) and negative (Physiological Saline Solution (PSS)) controls were included. Animals treated with GlcNAc or AmeGlc showed no clinical signs of infection and exhibited a significant reduction (p < 0.05) in the severity of microscopic lesions evaluated in the nasal cavity and lung compared with the positive controls. Additionally, the presence of bacteria was not detected through microbiological isolation or PCR in the lungs of animals treated with these sugars. Use of a mixture of GlcNAc and AmeGlc resulted in greater inhibition of microscopic lesions, with a significant reduction (p < 0.05) in the severity of these lesions compared to the results obtained using individual sugars. Furthermore, the bacterium was not detected through microbiological isolation, Polymerase Chain Reaction (PCR) or indirect immunoperoxidase (IIP) in this group.

Hamartomas nasales adenomatoides respiratorios. Reporte de cuatro casos / Respiratory adenomatoid nasal hamartomas. Four cases report

Los hamartomas son lesiones epiteliales de tipo benigno caracterizados por una proliferación de células típicas del tejido originario con distribución y organización diferente a la común. El hamartoma nasal es una lesión poco frecuente, que suele ser un hallazgo casual en la biopsia. Presentamos una serie de 4 pacientes diagnosticados de hamartoma del epitelio respiratorio, que clínicamente se presentan como pólipos u obstrucciones a nivel de cavum bilaterales

The hamartoma are epithelial lesions categorized as benign which are known for being a proliferation of typical cells of the original tissue but with unusual distribution and organisation. The nasal hamartoma is a short known lesion, which typically is found as a causal discovery. Below we present a series of 4 patients diagnosed with hamartoma of respiratory epithelium that are presented clinically as polyps or cavum bilateral obstruction.

Probiotics supplementation reduces cigarette smoke-induced damage in the respiratory micro-architecture of mice / Suplementação com probióticos reduz os danos causados pela fumaça de cigarro na microarquitetura respiratória de camundongos

This study evaluated the protective efficacy of probiotics supplementation against cigarette smoke-induced lung emphysema, inflammation, and loss of cilia in mice. Probiotics are known to promote mucosal tolerance and mitigate respiratory injuries. Twenty-four adult mice were randomly divided into three groups: control (Ctr), cigarette smoke (CS), and cigarette smoke + probiotics (CS+P). Probiotics were given for 7 days before exposure to smoke in the CS+P group. Tissue samples of the trachea (goblet cell count and index, loss of cilia), lungs (airspace distention), and bronchoalveolar lavage fluid (BALF) were collected and processed. The results showed a significant increase in acidic and neutral goblet cells in the CS group compared to the Ctr and CS+P groups (P < 0.05). Overall, goblet cell number and index were lower in the CS+P group (41.71 ± 5.76, 0.67 ± 0.073) than CS group (56.28 ± 5.34, 1.31 ± 0.28). Inflammatory cells and loss of cilia significantly decreased in mice fed probiotics before exposure to cigarette smoke (P < 0.05). Lung emphysema was also significantly reduced in the CS+P group compared to the CS group (P < 0.05). In conclusion, dietary supplementation of probiotics reduced lung emphysema, inflammatory cells, goblet cell index, and loss of cilia under conditions of cigarette smoke exposure in mice.(AU)

O presente trabalho avaliou a eficácia da suplementação com probióticos contra a indução de enfisema, inflamação e perda de cílios por fumaça de cigarro em camundongos. Sabe-se que os probióticos promovem a tolerância da mucosa e mitigam as injúrias respiratórias. Vinte e quatro camundongos foram divididos, ao acaso, em três grupos: controle (CTR), fumaça de cigarro (CS) e fumaça de cigarro + probióticos (CS+P). Os probióticos foram fornecidos por sete dias antes da exposição à fumaça no grupo CS+P. Foram colhidas e processadas amostras de tecidos da traqueia (contagem de células caliciformes e index, perda de cílios), pulmões (distensão do espaço aéreo) e fluido de lavagem broncoalveolar. Os resultados obtidos revelaram um aumento significativo em células caliciformes acidificadas e neutralizadas no grupo CS quando comparado aos grupos Ctr e CS+P (P<0,05). Os números global e o índice de células caliciformes foram menores no grupo CS+P (41,71+ 5,76; 0,67+ 0,073) que no grupo CS (56,28+ 5,34 e 1,131+ 0,28). As células inflamatórias e a perda de cílios decresceram em camundongos alimentados com probióticos antes da exposição à fumaça de cigarro (P<0,05). O enfisema pulmonar também foi significativamente reduzido no grupo CS+P quando comparado ao grupo CS (P<0,05). A conclusão obtida foi que o fornecimento de dieta suplementada com probióticos reduziu o enfisema pulmonar, as células inflamatórias, o índice de células caliciformes e a perda de cílios nos camundongos expostos à fumaça de cigarro.(AU)

Metformin-induced alterations in gills of the freshwater fish Astyanax lacustris (Lütken, 1875) detected by histological and scanning electron microscopy.

The antidiabetic drug metformin is widely prescribed and found in different concentrations in the environment around the world, raising concern about potential impacts on aquatic life. Analyses of the effects of exposure of biological models to aquatic contaminants are important for assessing pollution effects on fish health. The gills of fishes represent primary targets of disturbance by pollutants, mainly because of the large surface of the respiratory epithelium and the high perfusion rate, which both help the entry of pollutants into this tissue. In this context, the aim of this work was to use gill histological analyses biomarkers to evaluate the toxicity of metformin on aquatic environmental systems, by means of chronic exposure for 90 days of Astyanax lacustris (lambari), an ecologically important neotropical species that can be used as an environmental bioindicator. Histopathological analyses were performed using Light and Scanning Electron Microscopy. The main changes were lamellar fusion, telangiectasia hyperplasia and disappearance of microridges. The morphological changes observed possibly interfere with the gill physiology, indicating an unfavorable situation to the presence of metformin in the water, pointing to a concern that metformin may pose a risk to Astyanax lacustris and likely to other fish species, compromising the dynamics of the aquatic ecosystem as a whole. Graphical abstract.

Evaluation of the usefulness of vitamin D as a predictor of mortality in patients with COVID-19.

INTRODUCTION: One of the functions of vitamin D is to regulate respiratory epithelium inflammatory response; therefore, deficiency of this vitamin in the context of COVID-19 could constitute a predictive biomarker of the disease outcome. OBJECTIVE: To evaluate the usefulness of vitamin D for predicting mortality in patients with COVID-19. METHODS: Observational, retrospective study in which 154 patients diagnosed with COVID-19 were included, out of whom 111 survived and 43 died. Vitamin D concentration was determined in all of them. RESULTS: A log-rank p-value < 0.032 was obtained for survival when vitamin D concentration was used as a categorical variable (≤ 20 ng/mL and > 20 ng/mL). On Cox proportional analysis, age and vitamin D concentration were shown to be risk factors associated with mortality in patients with COVID-19 (age: HR = 1.036, 95% CI = 1.016-1.058, p < 0.001; vitamin D: HR (≤ 20 ng/mL and > 20 ng/mL) = 0.478, 95% CI = 0.237-0.966, p < 0.040). CONCLUSION: Age and vitamin D concentration were predictive factors for mortality in COVID-19-infected patients.

INTRODUCCIÓN: Una de las funciones de la vitamina D es regular la respuesta inflamatoria del epitelio respiratorio; por ello, la deficiencia de esa vitamina en el contexto de COVID-19 podría constituir un biomarcador preditivo del desenlace de COVID-19. OBJETIVO: Evaluar la utilidad de la vitamina D para predecir la mortalidad en pacientes con COVID-19. MÉTODOS: Estudio observacional y retrospectivo en el que se incluyeron 154 pacientes con diagnóstico de COVID-19, de los cuales 111 sobrevivieron y 43 fallecieron. En todos se determinó la concentración de vitamina D. RESULTADOS: Se obtuvo un valor log-rank de p < 0.032 para la supervivencia al utilizar la concentración de vitamina D como variable categórica (≤ 20 ng/mL y > 20 ng/mL). Mediante análisis proporcional de Cox se encontró que la edad y concentración de vitamina D mostraron ser factores de riesgo asociados a la mortalidad en pacientes con COVID-19 (edad: HR = 1.036, IC 95 % = 1.016-1.058, p < 0.001; vitamina D: HR ≤ 20 ng/mL y > 20 ng/mL = 0.478, IC 95 % = 0.237-0.966, p < 0.040). CONCLUSIÓN: La edad y la concentración de vitamina D constituyeron factores predictivos de mortalidad en pacientes infectados por COVID-19.

Evaluación de la utilidad de la vitamina D como predictor de mortalidad en pacientes con COVID-19 / Evaluation of the usefulness of vitamin D as a predictor of mortality in patients with COVID-19

Resumen Introducción: Una de las funciones de la vitamina D es regular la respuesta inflamatoria del epitelio respiratorio; por ello, la deficiencia de esa vitamina en el contexto de COVID-19 podría constituir un biomarcador preditivo del desenlace de COVID-19. Objetivo: Evaluar la utilidad de la vitamina D para predecir la mortalidad en pacientes con COVID-19. Métodos: Estudio observacional y retrospectivo en el que se incluyeron 154 pacientes con diagnóstico de COVID-19, de los cuales 111 sobrevivieron y 43 fallecieron. En todos se determinó la concentración de vitamina D. Resultados: Se obtuvo un valor log-rank de p < 0.032 para la supervivencia al utilizar la concentración de vitamina D como variable categórica (≤ 20 ng/mL y > 20 ng/mL). Mediante análisis proporcional de Cox se encontró que la edad y concentración de vitamina D mostraron ser factores de riesgo asociados a la mortalidad en pacientes con COVID-19 (edad: HR = 1.036, IC 95 % = 1.016-1.058, p < 0.001; vitamina D: HR ≤ 20 ng/mL y > 20 ng/mL = 0.478, IC 95 % = 0.237-0.966, p < 0.040). Conclusión: La edad y la concentración de vitamina D constituyeron factores predictivos de mortalidad en pacientes infectados por COVID-19.

Abstract Introduction: One of the functions of vitamin D is to regulate respiratory epithelium inflammatory response; therefore, deficiency of this vitamin in the context of COVID-19 could constitute a predictive biomarker of the disease outcome. Objective: To evaluate the usefulness of vitamin D for predicting mortality in patients with COVID-19. Methods: Observational, retrospective study in which 154 patients diagnosed with COVID-19 were included, out of whom 111 survived and 43 died. Vitamin D concentration was determined in all of them. Results: A log-rank p-value < 0.032 was obtained for survival when vitamin D concentration was used as a categorical variable (≤ 20 ng/mL and > 20 ng/mL). On Cox proportional analysis, age and vitamin D concentration were shown to be risk factors associated with mortality in patients with COVID-19 (age: HR = 1.036, 95% CI = 1.016-1.058, p < 0.001; vitamin D: HR [≤ 20 ng/mL and > 20 ng/mL] = 0.478, 95% CI = 0.237-0.966, p < 0.040). Conclusion: Age and vitamin D concentration were predictive factors for mortality in COVID-19-infected patients.

A Case Report of a Lingual Cyst Lined by Respiratory Epithelium in a Child.

The lingual cyst lined by respiratory epithelium is a rare pathology. It probably appears from the default of undifferentiated cells of the foregut during embryonic growth. This pathology is seen more often in males and children; however, only 5 patients younger than 4 years old have been reported. The pathophysiology and the management of this cyst were described in a 4-year-old girl. She presented with a soft mass on the dorsum of the tongue covered by normal mucosa, which existed since her birth, causing difficulty in eating, breathing, and talking. The magnetic resonance described a hyperintense image with an anteroposterior diameter of 27 mm, craniocaudal of 19 mm, and transversal of 26 mm in the midline groove of the tongue; the scintigraphy showed normality. The enucleation of the lesion was performed, eradicating the capsule of the cyst and obtaining a complete cleavage. The histopathologic examination defined a cyst lined predominantly by respiratory epithelium. Unlike in other cases, in this case their cystic lining and capsular constituents were contemplated considering the current histological recommendations. It is relevant to differentiate this pathology from other cysts with similar histological findings.

Dystrophic calcification and respiratory metaplasia in the epithelial lining of odontogenic cysts: a study of 362 odontogenic cysts in a Brazilian population and literature review.

PURPOSE: Main study: undertake a histological study of odontogenic cysts (OC) to determine the prevalence of dystrophic calcification and metaplasia to respiratory epithelium on a Brazilian population. LITERATURE REVIEW: to review the literature for studies that investigated the prevalence of respiratory metaplasia and dystrophic calcification on OC. METHODS: Main study: a retrospective histopathological evaluation was made of the archives from a pathology laboratory. A total of 362 cases diagnosed as OC were identified; they were analyzed by two expert observers to determine the presence of dystrophic calcification and respiratory metaplasia. The association with sex, age and anatomic location was performed through statistical analysis. LITERATURE REVIEW: a critical literature review was undertaken. Two main electronic databases (PubMed and LILACS) were searched. Retrospective studies of histological evaluation that determined the prevalence of epithelial metaplasia and dystrophic calcification on OC, with at least 10 cases, were included; their findings were summarized and discussed. RESULTS: Main study: the histological evaluation of OC revealed the presence of respiratory epithelium in 25 cases (6.9%) and dystrophic calcification in 24 cases (6.6%). Positive association was found to dystrophic calcification on residual cyst and age; respiratory metaplasia on OC and sex; respiratory metaplasia on residual cyst and gnatic bone; respiratory metaplasia in OC and gnatic bone; dystrophic calcification in OC and anatomic site of mandible. LITERATURE REVIEW: eleven studies were included in the literature review, and respiratory metaplasia ranged from 0.0% to 19.2% while dystrophic calcification ranged from 2.5% to 40.5%. CONCLUSIONS: the histological evaluation of this study found 6.9% of prevalence of respiratory metaplasia and 6.6% of dystrophic calcification, which is in accordance with the literature reviewed. Therefore, these phenomena must be taken into account in routine diagnosis services.

Histopathologic alterations of gill tissue in Siluriformes and Characiformes from the Middle Tocantins River in the Brazilian Amazon / Alterações histopatológicas do tecido branquial em Siluriformes e Characiformes do médio rio Tocantins, na Amazônia brasileira

As águas do rio Tocantins têm sofrido descargas de dejetos tóxicos que ameaçam a biota aquática. Para tanto, a investigação das brânquias de peixes atua como biomonitoramento, visto que esses órgãos respondem por meio de adaptações a xenobióticos. Este trabalho teve como objetivo avaliar a ocorrência de alterações morfológicas das espécies de Psectrogaster amazonica, Pimelodina flavipinnis e Pimelodus blochii. As coletas ocorreram nas estações chuvosa e seca. As brânquias de todos os espécimes coletados foram processadas de acordo com metodologia específica para protocolo de hematoxilina e eosina. As principais alterações histológicas observadas no período chuvoso foram: hiperplasia, destacamento do epitélio filamentar, fusão parcial e total das lamelas secundárias, congestão, aneurisma e encurtamento das lamelas respiratórias. Em relação ao período seco, as principais lesões observadas foram: ruptura do epitélio, aneurisma, hiperplasia e necrose. Considerando a diversidade ictiológica do rio Tocantins, o presente estudo propiciará o conhecimento da condição das brânquias, órgão imprescindível para a saúde do peixe, e consequentemente a compreensão das implicações sobre a qualidade das águas do rio Tocantins.(AU)

Histopathologic alterations of gill tissue in Siluriformes and Characiformes from the Middle Tocantins River in the Brazilian Amazon / Alterações histopatológicas do tecido branquial em Siluriformes e Characiformes do médio rio Tocantins, na Amazônia brasileira

As águas do rio Tocantins têm sofrido descargas de dejetos tóxicos que ameaçam a biota aquática. Para tanto, a investigação das brânquias de peixes atua como biomonitoramento, visto que esses órgãos respondem por meio de adaptações a xenobióticos. Este trabalho teve como objetivo avaliar a ocorrência de alterações morfológicas das espécies de Psectrogaster amazonica, Pimelodina flavipinnis e Pimelodus blochii. As coletas ocorreram nas estações chuvosa e seca. As brânquias de todos os espécimes coletados foram processadas de acordo com metodologia específica para protocolo de hematoxilina e eosina. As principais alterações histológicas observadas no período chuvoso foram: hiperplasia, destacamento do epitélio filamentar, fusão parcial e total das lamelas secundárias, congestão, aneurisma e encurtamento das lamelas respiratórias. Em relação ao período seco, as principais lesões observadas foram: ruptura do epitélio, aneurisma, hiperplasia e necrose. Considerando a diversidade ictiológica do rio Tocantins, o presente estudo propiciará o conhecimento da condição das brânquias, órgão imprescindível para a saúde do peixe, e consequentemente a compreensão das implicações sobre a qualidade das águas do rio Tocantins.(AU)

Tissue Distribution of Kir7.1 Inwardly Rectifying K+ Channel Probed in a Knock-in Mouse Expressing a Haemagglutinin-Tagged Protein.

Kir7.1 encoded by the Kcnj13 gene in the mouse is an inwardly rectifying K+ channel present in epithelia where it shares membrane localization with the Na+/K+-pump. Further investigations of the localisation and function of Kir7.1 would benefit from the availability of a knockout mouse, but perinatal mortality attributed to cleft palate in the neonate has thwarted this research. To facilitate localisation studies we now use CRISPR/Cas9 technology to generate a knock-in mouse, the Kir7.1-HA that expresses the channel tagged with a haemagglutinin (HA) epitope. The availability of antibodies for the HA epitope allows for application of western blot and immunolocalisation methods using widely available anti-HA antibodies with WT tissues providing unambiguous negative control. We demonstrate that Kir7.1-HA cloned from the choroid plexus of the knock-in mouse has the electrophysiological properties of the native channel, including characteristically large Rb+ currents. These large Kir7.1-mediated currents are accompanied by abundant apical membrane Kir7.1-HA immunoreactivity. WT-controlled western blots demonstrate the presence of Kir7.1-HA in the eye and the choroid plexus, trachea and lung, and intestinal epithelium but exclusively in the ileum. In the kidney, and at variance with previous reports in the rat and guinea-pig, Kir7.1-HA is expressed in the inner medulla but not in the cortex or outer medulla. In isolated tubules immunoreactivity was associated with inner medulla collecting ducts but not thin limbs of the loop of Henle. Kir7.1-HA shows basolateral expression in the respiratory tract epithelium from trachea to bronchioli. The channel also appears basolateral in the epithelium of the nasal cavity and nasopharynx in newborn animals. We show that HA-tagged Kir7.1 channel introduced in the mouse by a knock-in procedure has functional properties similar to the native protein and the animal thus generated has clear advantages in localisation studies. It might therefore become a useful tool to unravel Kir7.1 function in the different organs where it is expressed.

Expression of mesenchymal stem cell phenotype in human nasal respiratory epithelial cells / Expresión del fenotipo de células troncales mesenquimales en células epiteliales nasales humanas

The respiratory epithelium is the first line of contact with the external hazards. Thus it can be damaged and need to be replaced to avoid healing by fibrosis. Tracheal tissue engineering is an alternative promising treatment modality. Mesenchymal stem cell markers are surface proteins, which are responsible for some of these cells unique properties. The objective of this study was to detect the mesenchymal stem cell phenotype among the human nasal respiratory epithelial cells via two immunophenotyping techniques. Respiratory epithelial cells were cultured using co-culture technique, fibroblasts was removed at confluence leaving respiratory epithelial cells, which were passage further to passage 4. Cells were evaluated for mesenchymal stem cell markers that were CD73, CD90, CD105 and the hematopoietic stem cell marker CD45 at passage 1 (P1) and passage 4 (P4) using Flow cytometry and Immunocytochemistry techniques. Respiratory epithelial cells expressed the mesenchymal stem cell markers at P1 and maintain the expression these markers until P4. Using both techniques, to compare the values of mesenchymal stem cell markers expression at P1 to P4 there was no significant difference. This study indicates that respiratory epithelial cells derived from nasal turbinate retain some of mesenchymal stem cells properties even after serial passages. Both methods of Immunophenotyping are comparable.

El epitelio respiratorio es la primera línea de contacto con los peligros externos. Por lo tanto, puede ser dañado y necesita ser reemplazado para evitar uan cicatrización por fibrosis. La ingeniería de tejidos traqueales es una modalidad de tratamiento alternativo prometedora. Los marcadores de células troncales mesenquimales son proteínas de superficie, que son responsables de algunas propiedades únicas de estas células. El objetivo fue detectar el fenotipo de células troncales mesenquimales entre las células epiteliales respiratorias nasales humanas a través de dos técnicas de inmunofenotipaje. Fueron cultivadas las células epiteliales respiratorias utilizando la técnica de co-cultivo; los fibroblastos se eliminaron en la confluencia dejando solo células epiteliales respiratorias, resultantes de los 4 pasajes. Las células fueron evaluadas para encontrar marcadores de células troncales mesenquimales mediante CD73, CD90, CD105 y el marcador de células troncales hematopoyéticas CD45 en el paso 1 (P1) y el paso 4 (P4), usando citometría de flujo y técnicas de inmunocitoquímica. Las células epiteliales respiratorias expresaron los marcadores de células troncales mesenquimales en P1 y mantuvieron la expresión de estos marcadores hasta P4. No hubo diferencias significativas en el uso de ambas técnicas al comparar los valores de los marcadores de células troncales mesenquimales expresadas desde P1 a P4. Este estudio indica que las células epiteliales respiratorias derivadas de la concha nasal retienen algunas de las propiedades de células troncales mesenquimales, incluso después de pases seriados. Ambos métodos de inmunofenotipificación son comparables.

Acción del Etanol sobre el Epitelio Nasal y Glándulas Septales de Ratas, Durante la Lactancia / Action of Ethanol on Rat Pups Nasal Epithelium and Septal Glands, During Lactation

El consumo materno de etanol durante la lactancia altera la composición de la leche, provoca la aparición de etanol y acetaldehído en la leche y agrava los efectos del etanol en las crías de ratas. De este modo, fueron estudiados los efectos del etanol, administrado a las ratas madres durante la lactancia, sobre el epitelio respiratorio y en las glándulas septales anterior y posterior de las crías lactantes con 21 días de vida postnatal. Las ratas recibieron etanol al 20% en el bebedero, ad libitum durante los 21 días que amamantaron. Los controles recibieron un volumen similar de agua sin alcohol. Las crías fueron sacrificadas en el 21 día. Las cabezas fueran cortadas frontalmente. Los cortes seriados de 6 µm de grosor fueron teñidos con hematoxilina y eosina. Fueron determinados los parámetros nucleares de los epitelios respiratorio y glandular, así como los volúmenes citoplasmático y celular, relación núcleo-citoplasma, densidades numérica y superficial y espesor del epitelio. El peso corporal medio de las crías control fue 34,9 g y en las tratadas 20,2 g. Histologicamente, el epitelio respiratorio se mostró adelgazado en el grupo tratado, constituido por células abundantes y menores, con núcleos menores. La glándula septal posterior presentó ácinos menores. En este trabajo, el etanol indujo un cuadro de hipotrofia epitelial (respiratorio y glandular), indicando una acción directa sobre las células de la mucosa nasal, además de retardar el desarrollo de las crías intoxicadas.

Maternal ingestion of ethanol during lactation alters the chemical composition of milk, results in the appearance of ethanol and acetaldehyde in milk, and exacerbates the effects of ethanol on the rat pups. So that, the effect on respiratory epithelium and anterior and posterior septal glands in 21-day-old suckling pups of ethanol treated mothers was studied. Female rats received dinking water ad libitum containing ethanol (20%) throughout the whole lactation. Control animals received a similar volume of water without ethanol. Lactent rats (21 day-old) were killed by lethal dose of anesthetic. The heads were serially sectioned (6µm thick) in a frontal plain, and stained with haematoxylin and eosin. Cell nuclear parameters were estimated, as well as cytoplasm and cell volume, nucleus-cytoplasm ratio, number and surface densities, and epithelial thickness. Mean body weight of the pups was 34.9 g for the controls and 20.2 g for the treated group. Histologically, the respiratory epithelium was thinner, with more numerous and smaller cells and small nuclei. The posterior septal glands showed smaller acini. In this paper, ethanol induced epithelial (respiratory and glandular) hypotrophy, indicating a direct action in nasal mucous cells, besides retarded development in pups.