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Biomedical subjects

A Calvo

Publications and source records attributed to A Calvo.

At least 37 records · Page 2Linked to original sources
PubMed1997

Morphological and histochemical changes in the epididymis of hamsters (Mesocricetus auratus) subjected to short photoperiod.

The morphological involution and histochemical changes of the Syrian hamster (Mesocricetus auratus) epididymis induced by a short light period were investigated. Under short-day conditions, the epididymis showed marked morphological changes including a decrease in luminal diameter, disappearance of spermatozoa, increase of interductal tissue, increase of intraepithelial lipofuscin deposits, the presence of phagolysosomes in the principal cells and macrophage-like cells, and a considerable modification of most clear cells. With lectin histochemistry changes were found in the glycoconjugates of principal cells of the regressed epididymis, either a decrease (PNA, WGA, HPA and DBA) or an increase (MAA) in the affinity of lectins to the Golgi area, or a decrease (HPA) or an increase (PNA) in lectin binding to stereocilia. Both morphological and histochemical results showed that, under this light condition, the cauda epididymidis presented the most prominent alterations, and that the epididymis showed increased absorptive activity and a decreased synthesis of glycoproteins. All these changes are probably due to the decrease in testosterone levels.

Animals↗
PubMed1997

[Risk factors for gallbladder cancer in Chilean females].

A case-control study of gallbladder cancer was conducted with 90 Chilean cases registered at one hospital in Santiago city, Chile from January, 1992 to August, 1994. Controls were selected among outpatients of the hospital who received abdominal echography. Each case was assigned 2 age- and sex-matched controls; either with or without gallstone(s). Study subjects were all directly interviewed by well-trained medical students. The present study focused on 74 female pairs and the following findings were obtained: 1) Odds Ratio(OR)s were significantly high for education years less than or equal to 6, body mass index greater than or equal to 24.0, constipation, and consumption of egg, fried meals, green and red chili. Chili pepper consumption of both types in cases showed significantly elevated risks with higher frequency. 2) While high ORs were observed, biliary symptoms such as dyspepsia and past history of cholelithiasis were strongly involved with present gallstone(s) and may not be independent factors for gallbladder cancer. 3) Significantly low ORs were seen for past history of intestinal parasitosis and surgical operation, hormone therapy, all industrial workers and workers in clothes & textile industry. However results may be influenced by more years of education or recall bias. 4) When a conditional logistic model was applied and controls with gallstone(s) were taken as reference, those with the habit of constipation showed a significantly high risk of 2.10 (95% CI: 1.01-4.38), and the consumers of red chili with a frequency > or = 1 time/day had elevated risks of 2.16 (1.27-3.66) vs those < 1 time/day and 4.66 (1.63-13.40) vs non-consumers, respectively. From the above results, the occurrence of gallbladder cancer in Chilean females may be related to constipation and chili pepper consumption, based on the presence of gallstone(s). Further investigations are needed to elucidate whether these are actual risk factors or whether only a false association was detected.

Case-Control Studies↗
PubMed1996

Lectin histochemistry during in vitro capacitation and acrosome reaction in boar spermatozoa: new lectins for evaluating acrosomal status of boar spermatozoa.

Six peroxidase (HRP)-conjugated lectins have been used to analyze the distribution of carbohydrates in ejaculated boar spermatozoa during in vitro capacitation and acrosome reaction in air-dried preparations. The membranes of boar spermatozoa were positive to WGA and Con-A in the acrosome, middle piece and principal piece. PNA labelled the acrosomal region. DBA, UEA-I and LTA bound weakly or not to the spermatozoa. The lectin labelling pattern did not change during the in vitro capacitation. A diminution in the proportion of spermatozoa with acrosome positive to lectins PNA, WGA and Con-A was observed after coincubation with homologous immature oocytes. A positive correlation existed between the percentages of lectins bound to spermatozoa and the triple stain technique. The results show that peroxidase-conjugated lectins may be useful in determining acrosomal integrity of boar spermatozoa during in vitro capacitation and acrosome reaction.

Acrosome↗
PubMed1996

Morphological and morphometric study of early changes in the ageing golden hamster testis.

The histological and morphometric features of the aged golden hamster testis were examined and compared with those of adult animals. Three age groups (6, 12 and 18 months) were studied by light microscopy, and testosterone levels were determined. The observations showed a progressive involution of the seminiferous tubules, beginning to be perceptible at 12 months with slight hypospermatogenesis and desquamation. In 18-month-old specimens degeneration was more significant and histopathological lesions could be classified on a 6-point scale, ranging from slight hypospermatogenesis to absence of germ cells. These involutive changes were not homogeneously distributed in the testis; affected tubules close to seeming normal ones were present. The morphometric results point to a progressive diminution, in the 3 age groups, in vas deferens spermatozoa, pachytene spermatocytes, and Sertoli and Leydig cells (the latter significantly diminished only in the 18-month-old group). For morphometric purposes a 7-point scale of tubule degeneration was used, showing a significant increase, with age, in the presence of more degenerated tubule stages. Several correlations were found between the morphometric variables, outlining existing relations between age and the associated diminution of several testis cell types, and lumen diameter. No significant differences were found between groups in serum testosterone levels. In conclusion, histological changes related to age are evident in 18-month-old animals, while at 12 months a diminution in germ cell numbers and sperm production is detectable.

Aging↗
PubMed1996

[Anesthetic complications in sequential bipulmonary transplantation in patients with cystic fibrosis. Apropos of 6 cases].

Cystic fibrosis (CF) is a disease characterized mainly by altered exocrine gland function that eventually produces irreversible dysfunction of the pancreas and lungs. The respiratory insufficiency that develops in CF patients in the advanced stages of disease can only be corrected at this time by lung or heart-lung transplantation. We describe our experience with 6 terminal phase CF patients who underwent sequential double lung transplantation (SDLT). Anesthesia was intravenous, with exhaustive hemodynamic and respiratory monitoring. During surgery the most frequently encountered hemodynamic complications were low minute volume, arterial hypotension and irregular heart rate. The main respiratory complications were hypoxemia, hypercapnia and pulmonary edema of the implanted lung, which developed in all cases to varying degrees related to the organ's state of preservation and duration of ischemia. Other complications were the need for extracorporeal circulation in 1 case, oliguria and blood loss requiring multiple transfusions. The most critical moments were at the time of clamping the pulmonary artery, the period after revascularization of the donated lung, and at the start of patient ventilation through the first implanted lung so that the second could be implanted. Although our series is small, it is of interest given the limited Spanish experience with lung transplantation in CF patients, and the good early results obtained, which are similar to those reported for other diseases.

Adolescent↗
PubMed1995

Abnormal spermatozoa in the cauda epididymidis of adult and aged hamsters (Mesocricetus auratus): a study by electron microscopy.

The morphology of the spermatozoa in the cauda epididymidis of 6- and 24-month-old (adult and aged) hamster was studied by electron microscopy. Lesions found in the spermatozoa included alterations in the acrosomal matrix and nuclear membranes, abnormal or absent mitochondria, alterations in the axonemes, dense fibres and microtubules, and bent flagella. All these abnormalities are similar to those found in other species and few alterations were exclusive to the older animals. Ultrastructurally abnormal spermatozoa were observed in both groups but were present at a significantly greater frequency in aged hamsters (p < 0.005). the percentage of sperm with abnormal acrosomes, mitochondria and dense fibres and of bent (but not disrupted) spermatozoa was significantly greater in the older animals. These results show that the ultrastructural alterations in hamster sperm are similar to those found in other mammals. Moreover, the percentage of ultrastructurally abnormal spermatozoa in aged hamsters is greater than 6-month-old hamsters, this increase is not accompanied by any new kinds of alteration.

Aging↗
PubMed1995

Histochemical study of glycoconjugates in the epididymis of the hamster (Mesocricetus auratus).

The glycoconjugates of hamster epididymis were investigated with conventional and lectin histochemistry. A zone of the caput epididymis, with particular histochemical characteristics, has been differentiated. beta-Elimination in combination with lectins was used to establish the presence and distribution of N- and O-linked glycoconjugates. The epithelium, spermatozoa and the intertubular matrix were rich in glycoconjugates. The Golgi apparatus and stereocilia of the principal cells were intensely positive with HPA, PNA and SBA lectins. beta-Elimination indicated that these cells contained abundant O-linked glycoconjugates. Apical and clear cells presented a common lectin affinity; their reactivities towards WGA and UEA-I were very positive. These cells probably contain abundant N-glycoconjugates. The spermatozoa were stained by periodic acid-Schiff (PAS) and by all the lectins (especially in the acrosome), except by those with an affinity for alpha-L-fucosyl residues; the most intense reaction was found with HPA, WGA, PNA and SBA. Changes in the sperm lectin binding along the ductus were observed: sperm flagellum abruptly acquired WGA and PNA labelling from the posterior caput, and HPA reactivity was negative only in the zone between the caput and the corpus.

Animals↗
PubMed1994

Morphological and histochemical study of human submucosal laryngeal glands.

BACKGROUND: The respiratory submucosal glands are a major source of secretions in the airway. Human submucosal laryngeal glands have been scarcely studied, with no works existing about their ultrastructure and histochemistry. METHODS: Samples of epiglottis, ventricle, false vocal folds and true vocal folds were fixed in 10% buffered formalin for histochemical study with conventional and carbohydrate lectin histochemistry. Other samples were fixed in 2.5% glutaraldehyde and conventionally processed for transmission electron microscopy. RESULTS: The human submucosal laryngeal glands are composed of serious tubules; mucous tubules; collector duct; and final portion of this duct. The serous cells showed sialosulphomucins and affinity for WGA and Con-A lectins. With a previous treatment with neuraminidase, they also labelled with PNA. The mucous cells contained sialosulphomucins and showed affinity for WGA and DBA lectins in the samples proceeding from blood group A, and for WGA, UEA-I and LTA with those from blood group O. Ultrastructurally, the serous cells presented a wide variety of granules, cells in which seromucous granules predominated. The mucous cells presented larger-sized granules which were very electron-lucent. The collector duct was composed of mitochondria-rich cells and basal cells. A cell which we have termed "intermediate" was identified in the transition zone between the mucous tubules and the collector duct, and in the final portion of the collector duct. It had morphological characteristics as if it were a transition between a goblet cell and collector duct cell. Some nerve endings with cholinergic and peptidergic vesicles were found among the myoepithelial cells. CONCLUSIONS: These glands presented some histological differences from the bronchial glands, the mucous secretion was related to the blood group antigens, and the serous cells showed a wide variability in their secretory granules, many of them being of a seromucous type.

Adult↗
PubMed1994

Nerve endings in the epithelium and submucosa of human epiglottis.

An electron-microscopic study of the sensory innervation of human epiglottis was undertaken. The nerve supply of this structure was abundant; numerous free unmyelinated nerve endings of 2.5-3 microns were observed in the stratified epithelium of the epiglottis associated with clear cells containing mitochondria, rough endoplasmic reticulum, microtubules and dense-cored granules. The nerve and cell complex resembled a corpuscular structure, probably of a quimiosensitive character. In the submucosa, unmyelinated nerves were observed which may come from deeper myelinated trunks, and some of them entered the epithelium. Encapsulated corpuscles were also found in the submucosa. Four elements could be distinguished: nerve endings, lamellar cells, interlamellar substance, and capsule. Our observations at an ultrastructural level complete previous observations by means of light microscopy indicating that the epiglottis is a zone with an important innervation in the epithelium as well as in the submucosa. This sensory innervation probably bears a relation to reflexes, such as cough and deglution, to protect the airways.

Axons↗
PubMed1993

Immunological evaluation of patients with invasive carcinoma of the gallbladder.

Forty-three patients with invasive adenocarcinoma of the gallbladder were postoperatively studied in order to determine their general immunological status as well as the local immunohistological reaction to the tumor. At the end of the follow-up, they formed two groups: 19 living patients (group GL) and 24 dead patients (group GD). As a control group (GC), 21 patients with cholecystectomy or cholelithiasis and without carcinoma were simultaneously evaluated. In GL, most of the tumors were limited to the gallbladder wall, and in GD, most of the tumors were already disseminated at the time of diagnosis. GD presented a lower percentage of peripheral blood B lymphocytes, as compared to GL and GC cases. Skin tests of delayed hypersensitivity were significantly more reactive in GL cases than in GD cases, and less reactive in GD than in GC cases. The immunohistological evaluation of the gallbladder yielded a lower B lymphocyte infiltration in GD tumors than in the control cases. GL cases showed a higher intratumoral lymphocytic and mononuclear cell infiltration than GD cases. Although the clinical stage was higher in GD than in GL cases, there were also significant differences in the local immune response and the general immunological status. Patients with invasive gallbladder adenocarcinoma showing longer postoperative survival revealed normal or increased local and general immunological reactions, whereas patients with disseminated tumors showed an important humoral and cellular secondary immunodeficiency.

Adenocarcinoma↗
PubMed1993

[Perinatal and maternal pathology in 38 pregnant women with endemic goiter].

In a group of 38 pregnant women with primary, uni- or multinodular non-toxic endemic goitre, who were clinically euthyroid, 7.8% (3 cases) had previously undergone strumectomy for benign pathologies of the goitre and 10.5% (4 cases) received L-thyroxine therapy during pregnancy at a dose of 50 or 100 micrograms/day; during the course of pregnancy goitre was asymptomatic in 37 women (97.4%) and an endocystic hemorrhage occurred in 1 (2.6%) case. The goitre increased in volume in 42.1% (16 cases) of pregnant women monitored to term. Out of 20 patients undergoing ELISA of hormonal levels, 6 (30%) revealed TSH concentration more than twice the maximum normal value with normal concentrations of other thyroid hormones. There was a significant inverse correlation (r = 0.525) between T4 and TSH. Birth at term occurred at 39.9 +/- 2.6 weeks and was spontaneous in 78.9% of cases (30 cases) and laparotomic in 21.1% (8 cases). Perinatal pathologies included: 1 case (2.6%) of endo-uterine fetal death, 1 case of oligoamnios and 1 of IUGR. Funicular pathologies were observed in 13.1% of patients (5 cases). The Apgar index was > 8 in the 37 live births. The mean weight of male and female neonates and neonates from nulliparas and pluriparas was within the norm. When the data examined were compared to the results of the control group it was seen that there were no statistically significant differences.

Adult↗
PubMed1993

[Obstetric and perinatal implications of thyroid pathology in pregnancy. Review of the literature].

The authors review the published data on thyroid pathology and pregnancy. Attention is focused in particular on alterations in thyroid function and the iodine metabolism during pregnancy, thyroid interactions between the fetus, the placenta and the maternal organism, the control of fetal thyroid hormonal production, thyroid hormones and fetal development, endemic goitre and pregnancy, endemic cretinism, hypothyroidism in pregnancy, mixematous coma, hyperthyroidism in pregnancy, thyroid cancer in pregnancy and perinatal thyroid disease (hypothyroidism and hyperthyroidism).

Adult↗
PubMed1993

Sternoclavicular brucellar arthritis: a report of 7 cases and a review of the literature.

OBJECTIVE: To describe the clinical features of sternoclavicular arthritis. METHODS: Medical records review of patients with sternoclavicular brucellar arthritis diagnosed and treated in a University Hospital in Lima, Peru. RESULTS: Over a 21-year period, 1,729 cases of brucellosis were diagnosed and treated. Seven patients with sternoclavicular arthritis were identified; 5 had an acute course with current or past evidence of systemic infection. Four patients had involvement of another joint and one of the 7 developed a chest wall abscess. All patients recovered without sequelae. CONCLUSION: Recovery without sequelae is expected if patients with sternoclavicular brucellar arthritis are promptly diagnosed and treated.

Adult↗
PubMed1992

Histology of the esophagus of the adult frog Rana perezi (Anura: Ranidae).

Study of the esophageal microscopic morphology of adult Rana perezi by light and electron microscopy discloses some large folds throughout the esophagus that are in themselves ringed. Glandular ostia open in the furrows of the luminal surface. The esophageal wall is made up of a connective adventitia rich in melanocytes, a muscular tunica, a connective and glandular subepithelial layer, and a pseudostratified ciliated epithelium. This epithelium basically consists of ciliated, goblet, basal, microvillous-apex, and migratory cells. Two types of goblet cells are distinguished with regard to the granular ultrastructure. The microvillous-apex cell has not been found in other amphibians. It shows a very differentiated morphology with a high number of mitochondria. The basal cells give the epithelium a pseudostratified morphology, and they have a proliferative function. Glands are branched and drain through an excretory duct that has a monolayered mucosecreting epithelium. The glandular units are formed by two principal types of cells: mucosecretory and serous.

Animals↗
PubMed1992

Histochemical study of glycoconjugates in the nasal mucosa of the rat and guinea pig.

A histochemical study was carried out on the glycoconjugates of the nasal mucosa of rat and guinea pig using conventional techniques and peroxidase-labelled lectins. Both the respiratory mucosa and neuroepithelium were studied. Sulphate and sialic acid groups were found in the mucous layer of the neuroepithelia, Bowman's glands and goblet cells. In contrast, the nasal glands did not possess these groups, and only a few showed neutral mucins. Carbohydrate residues were more numerous in the acini of the Jacobson glands. Thus, the nasal glands in the rat and guinea pig are probably of a serous type because of the scarcity of carbohydrate residues.

Animals↗