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Biomedical subjects

A Ruiz

Publications and source records attributed to A Ruiz.

At least 289 records · Page 16Linked to original sources
PubMed1986

Dome epithelial M cells dissociated from rabbit gut-associated lymphoid tissues.

Dome and dome epithelial cells were selectively dissociated from gut-associated lymphoid tissues of rabbits. Sequential tissue washes in dithiothreitol, EDTA, and collagenase removed the dome epithelium, without disrupting the follicles or villi, and provided a cell suspension containing 74 +/- 6% lymphocytes, 9 +/- 4% columnar epithelial cells, 10 +/- 7% tangible-body macrophages, and 4 +/- 2% M cells (follicle-associated epithelial cells). The last mentioned cells were characterized by transmission electron microscopy as large (20 to 55 microns diameter) cuboidal, round, or oval cells with eccentric nuclei and thin membranous processes surrounding empty vacuoles. The M cells were occasionally joined together by tight junctions. Histochemical and immunocytochemical analyses of M cells with the light microscope showed that they were devoid of immunoglobulins and negative for T-cell antigen and secretory component and had no detectable alkaline phosphatase or endogenous peroxidase activity. The M cells had few vacuoles with faint acid phosphatase activity; nonspecific neutral esterase was abundant. Possible uses for dome and dome epithelial cells are discussed.

Acid Phosphatase↗
PubMed1986

[Triad syndrome in the neonatal period: an anatomoclinical study of 11 cases].

Eleven newborn children with clinical and anatomic characteristics of Prune-Belly syndrome were studied. This establish an approximate incidence of 1:28,000 newborns. All these children died in the first-days of life, nine of them as a result of pulmonary hypoplasia secondary olygohydiamnios. All of them except one had urinary tract dilatation and in four anatomic stenosis of urethra was found as the cause of obstruction. These findings support mechanical theory more than a primary mesodermic disorder as a pathogenic mechanism. All this, together with establishment of an early prenatal diagnosis, opens the possibility of an intrauterine treatment which could free the urinary tract and prevent oligohydramnios and its, sequelae.

Female↗
PubMed1985

Leptospiral agglutinins among cattle in the Republic of Guyana.

Cattle sera collected in the Republic of Guyana during 1981 to 1982 were examined for serologic evidence of leptospirosis. Significant leptospiral agglutinins (1:100 or higher) were disclosed in 49.1% of 2,935 apparently normal cattle from 734 farms in the three major cattle-raising regions of the country. Seroreactions principally involved hardjo and wolffi of the Sejroe serogroup, icterohaemorrhagiae, pomona, tarassovi, canicola and grippotyphosa. A high proportion of reactions to one or more of different leptospiral serovars were observed in each of the three regions. These variations were attributed to differences in environmental conditions and farming practices. The findings provided evidence for the first time of the widespread occurrence of leptospirosis in cattle in Guyana caused by multiple leptospiral serovars.

Agglutinins↗
PubMed1985

Homeorhesis during early lactation. Euthyroid sick-like syndrome in lactating cows.

Serum levels of thyroxine (T4), triiodothyronine (T3) and reverse T3 (rT3) were studied in dry, early (first trimester) and middle (second trimester) lactating purebred Holstein cows. The study encompassed three different seasons: autumn, winter and spring. Under comfortable weather conditions (temperature 22 degrees C; relative humidity, 40%) or moderately hot (28 degrees C; 60%), January and October, respectively, cows in early lactation exhibited significantly lower levels of T4 and T3, and higher values of rT3 than dry or middle lactating animals. In contrast, during May, when environmental temperature increased (34 degrees C; 40%), a clear-cut shift in T3/rT3 ratio occurred, and animals in early lactation exhibited the highest T3 and the lowest rT3 concentrations. These findings suggest that in dairy cattle, peripheral thyroid hormone metabolism plays a major role in regulating the homeorhetic responses involved in the maintenance of high priority functions.

Adaptation, Physiological↗
PubMed1985

Conserved group-specific epitopes of the circumsporozoite proteins revealed by antibodies to synthetic peptides.

The immunogenic properties of sporozoites are associated mainly with the circumsporozoite (CS) protein that covers the surface of mature sporozoites. This stage-specific protein has an immunodominant region with repetitive epitopes. Rabbits that are repeatedly immunized with sporozoites of Plasmodium knowlesi, a monkey malaria parasite, also recognize two synthetic peptides (N2 and C2) representing other polar domains of the CS protein. We show in this report that antibodies to the N2 and C2 synthetic peptides react not only with P. knowlesi but also with conserved regions of the surface membrane of other human, monkey, and rodent (but not avian) malaria sporozoites. Moreover, antibodies to N2 partially neutralize the infectivity of sporozoites of P. berghei, a rodent malaria parasite. In contrast, antibodies to synthetic peptides representing the repetitive epitope of P. knowlesi were strictly species specific.

Animals↗
PubMed1983

Isolation and biochemical analysis of Mucor bacilliformis monomorphic mutants.

Fourteen stable mutants of Mucor bacilliformis which grew yeastlike under both aerobic and anaerobic conditions were isolated after treatment of growing mycelium with N-methyl-N'-nitro-N-nitrosoguanidine. Biochemical characterization of the mutants included determination of growth in different carbon and nitrogen sources, determination of sensitivity of respiration to cyanide and salicylhydroxamate, analysis of cytochrome spectra, determination of glutamate dehydrogenases, glutamine synthase, and ornithine decarboxylase activities, and measurement of cyclic AMP levels. Data showed that all mutants were defective in some aspect of oxidative metabolism and had low levels of ornithine decarboxylase, whereas other characters were variable. It was concluded that morphological transition in M. bacilliformis is probably associated with mitochondrial functions and expression of ornithine decarboxylase, but may be independent of cyclic AMP and glutamate dehydrogenase levels. The importance of genetic studies in the analysis of dimorphism is stressed.

Aerobiosis↗
PubMed1983

[Myocardial infarction and myocardial ischemia in newborn children and infants, not secondary to an abnormal coronary].

Three cases (one, newborn infant and two infants--one of them recently published--) who present electrocardiographic and enzymatic alterations comparative with diagnosis of ischemia and myocardial infarction are reported. Rarity of this entity in infants is stressed as most of published cases are secondary to ananomolous coronary artery. Etiology of the cases presented shows a myocardiac fibrosis with Schwachman's syndrome in one case, a coronary thrombosis secondary to a disseminated intravascular coagulation in a second case, and finally a generalized hypoplasia of coronary arteries. Hypoxia appears in these cases a factor acting in favour of myocardial ischemia. Diagnostic criteria of acute myocardial infarction are based on typical electrocardiogram and rise of isoenzymes of LDH and CPK-MB. Although rare, it is a diagnosis to be considered in cases of unknow cardiac insufficiency in newborns and infants.

Coronary Disease↗
PubMed1983

[Sacrococcygeal tumors. Experience of 42 cases].

From 1966 to 1981, at "La Paz" Children's Hospital, Madrid, 42 patients with ST were studied. We exclude 4 stillborn, the remaining 38 underwent 40 surgical operations, 69% in the first week of life. The aim of the study is to classify and organize from the clinical and pathological points of view the usual equivocal terminology. From a clinical point of view, sex, localization and age at diagnosis were the usually described for these tumors. The relationship of age with malignancy is pointed out. Special emphasis is made on the pathological information about undifferentiated blastodermic tissues, like neuroblasts pointing out their low influence in prognosis. 79% were mature teratomas and 21% malignant tumors (Yolk sac and embrional carcinoma).

Bone Neoplasms↗
PubMed1982

Serologic grouping and sexual compatibility of airborne Cryptococcus neoformans.

Through the use of Anderson air samples, 214 isolates of Cryptococcus neoformans were cultured from the air in a vacant tower in a large complex of buildings in Oklahoma City. The tower contained hundreds of pigeons, a massive amount of droppings, nests with eggs and young, dying and dead pigeons. All isolates were serotype A-D and self-sterile for the production of basidiospores. Among these 193 were of the "alpha" mating type, producing basidiospores when paired with "alpha" mating type. No isolates of "alpha" mating type were found. The findings imply that the infectious particles of C. neoformans in nature are relatively small, nonencapsulated yeast cells and not basidiospores.

Air Microbiology↗
PubMed1982

A one year study on the viability of Cryptococcus neoformans in nature.

Using four different assat procedures we found a 50 to 86% decrease in viability of Cryptococcus neoformans over a one year period after two towers in the Oklahoma City area were modified to exclude pigeons and weather elements, especially rain. In homogeneous pigeon dropping samples a sharp decrease in viability occurred after 7 to 9 months of storage. The decrease occurred in pigeon dropping samples maintained at the natural sites and at ambient temperature in the laboratory in the laboratory but not in droppings stored at -4 degrees C. Air sampling studies done at the natural sites before and after tower modifications also showed a decrease in C. neoformans viability. The decrease in viability cannot be explained by seasonal temperature variations that occurred at natural sites. Our findings suggest that death of C. neoformans occurred because of lack of available intracellular water exacerbated by low humidity, exclusion of precipitation and moisture from fresh pigeon droppings. In light of our experiences, at one site in south central United States, the feasibility of controlling C. neoformans at heavily contaminated sites, other than by the use of noxious or potentially dangerous chemicals, is discussed.

Air Microbiology↗
PubMed1982

Control of Cryptococcus neoformans in nature by biotic factors.

Two bacterial species (Pseudomonas aeruginosa and Bacillus subtilis) isolated from pigeon droppings, displayed anti Cryptococcus neoformans activity on 4 of 6 media and sterilized pigeon droppings. Acanthamoeba palestinensis trophozoites isolated from pigeon droppings ingested and killed 99.9% of C neoformans cells after 7 days of incubation. Mites and sow bugs (Metoponorthus pruinosus) isolated from pigeon droppings appear to be fungivorous. These findings suggest that many organisms that occur in pigeon droppings influence C. neoformans persistence, reproduction, morphology and distribution in nature.

Amoeba↗
PubMed1982

Enteropathy related to fish, rice, and chicken.

Gastrointestinal symptoms in relation to the ingestion of proteins are common but only in the case of sensitisation to cows' milk protein, soy, or gluten have alterations in the function and structure of the small-intestine been reported. We describe 3 children with cows' milk protein intolerance and associated enteropathy related to fish, rice, and chicken, respectively. Repeated intestinal biopsies before and after an acute challenge with the specific food showed changes in the histological appearance of the intestinal mucosa identical with those observed after the acute administration of cows' milk. These findings support the conclusion that cows' milk-protein intolerance is not an isolated entity; it represents the first part of a broader intolerance of various dietary proteins.

Animals↗
PubMed1981

Culture of Cryptococcus neoformans in the nonencapsulated state.

Forty-one strains of Cryptococcus neoformans were examined after 3 days growth on a fresh and aged medium at pH 5 & pH 7 for comparison of capsule formation. Over one-half of the strains did not form visible capsules on aged medium at pH 5. Serotypes and source of isolation did not correlate with ability or inability to form capsules. Growth of C. neoformans in the nonencapsulated state makes it possible to culture many strains of C. neoformans in the form that more closely simulates the true infectious particles.

Cryptococcus↗