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Biomedical subjects

M Pinto

Publications and source records attributed to M Pinto.

At least 73 records · Page 4Linked to original sources
PubMed1987

B-cell chronic lymphatic leukemia in Hodgkin's disease. A report of two patients with unusual chromosome features.

The development of B-cell chronic lymphatic leukemia in two patients who had previously been treated for Hodgkin's disease is described. In both cases aneuploidy and multiple chromosome aberrations of hemopoietic cells were evident. In one patient these changes included a clonal 14q + abnormality in association with other complex rearrangements, interpreted as translocation abnormalities involving t(6;14), 5(1;15), and t(17;19). Although the chromosome abnormalities in the other patient were nonclonal, a 14q abnormality also was detected, namely t(14q+;18q-). Other chromosome abnormalities (all nonclonal) in the two patients included translocations involving chromosome 5 and deletion of 7q in one patient and trisomy of chromosome 8 in the other. Although these abnormalities have been associated with the presence or development of non-Hodgkin's lymphoma, acute nonlymphoblastic anemia, or myelodysplastic disorders, the findings in these patients suggest that the detection of clones and potential clones with these abnormalities may be only one stage in the development of secondary malignancy.

Adult↗
PubMed1987

Effects of partial hepatectomy on the immune responses in mice.

Experiments were performed to investigate the immune responses occurring as a result of partial hepatectomy (HEP) in mice. On Day 12 mice subjected to HEP showed a twofold rise in serum levels of IgG when compared with sham-operated (ShO) controls. The effects of HEP on specific antibody production following a single immunization with sheep red blood cells (SRBCs) were investigated. An early appearance of direct (IgM) splenic plaque-forming cells (PFCs) and significantly elevated indirect (IgG) PFCs were found in HEP mice. Elevated, early-appearing mercaptoethanol-resistant (IgG) hemagglutinating antibodies were also demonstrated in the sera of HEP mice. In addition to these findings our study showed that humoral and cell-mediated responses are affected by HEP in opposing fashion. Partial hepatectomy performed immediately after skin grafting suppressed a first set allograft rejection in mice. Furthermore, inhibited delayed-type hypersensitivity (DTH) response against SRBCs, as evaluated by a footpad weight assay, was demonstrated in HEP mice compared with the ShO controls. When SRBC-primed mice were partially hepatectomized 15 days later, they responded in a manner typical of the secondary immune response, showing an increased production of indirect (IgG) splenic PFCs. A similar anamnestic response was observed in mice sensitized with leptospiral antigen 50 days prior to HEP or exposed to carbon tetrachloride (CCl4) hepatotoxin. The mice responded by elevated serum IgG-specific antibodies as measured by solid-phase enzyme-linked immunosorbent assay (ELISA). Since HEP induced in mice immunological disturbances similar to those associated with liver disease, it is suggested that partial hepatectomy creating liver deficiency followed by regeneration may be a useful experimental model to study the immune status of various forms of hepatic damage.

Animals↗
PubMed1987

Isolation of a cDNA probe for a human jejunal brush-border hydrolase, sucrase-isomaltase, and assignment of the gene locus to chromosome 3.

We report the nucleotide sequence and derived amino acid sequence of a cDNA clone encoding most of the N-terminal, isomaltase region of human sucrase-isomaltase (SI). A plasmid containing this cDNA, pS12, identifies a 6-kb mRNA found in human jejunum and the human colon carcinoma cell line Caco-2. This human SI cDNA shows extensive overall homology with recently published rabbit SI cDNA. Using pS12 to probe DNA from a panel of somatic cell hybrids, we have assigned the gene encoding human SI to chromosome 3.

Amino Acid Sequence↗
PubMed1987

Electrocardiographic changes during antihypertensive therapy in the International Prospective Primary Prevention Study in Hypertension.

In the International Prospective Primary Prevention Study in Hypertension, electrocardiographic changes before and during 3- to 5-year antihypertensive treatment were investigated in a cohort of 5819 men and women aged 40 to 64 years with entry diastolic blood pressures of 100 to 125 mm Hg. They were randomly allocated to treatment regimens that either included or excluded the slow-release beta-blocker oxprenolol. Electrocardiograms (ECGs) were assessed using the Minnesota Code and assigned to groups of normal ECGs or ECGs with pressure-related, ischemic, "intermediate," or "other" abnormalities. Antihypertensive treatment was associated with a decrease (mainly in men) of pressure-related and (mainly in women) of intermediate abnormalities. Ischemic abnormalities increased, particularly in men. Inclusion of the beta-blocker resulted in a greater reduction in intermediate abnormalities and in a lesser increase in ischemic abnormalities. Better blood pressure control was associated with a lesser increase in ischemic abnormalities and in a regression of pressure-related abnormalities. The presence of ST segment depression and of a complete left bundle branch block in the entry ECG was associated with a significant risk for sudden death and myocardial infarction. Optimal blood pressure control prevents pressure-induced cardiac target organ damage and, hence, heart failure, and may delay the progression of ischemic abnormalities. This tallies with the lower critical cardiac event rate associated with lower blood pressure that was observed in the same study.

Antihypertensive Agents↗
PubMed1986

Circulating somatostatin concentrations in healthy and cirrhotic subjects.

Plasma insulin, glucagon, somatostatin, and glucose concentrations were measured in the fasting state as well as after mixed meals (breakfast, lunch, and dinner) in 10 cirrhotic patients and 10 control subjects during a 24-hour period. Cirrhotic patients had fasting glucose values higher than controls (at -15 min: 5.2 +/- 0.2 mmol/L v 3.9 +/- 0.5 mmol/L, P less than 0.05; at 0 min: 5.5 +/- 0.3 mmol/L v 4.3 +/- 0.5 mmol/L, P less than 0.01). After meals blood glucose values remained higher in cirrhotics than in controls. Insulin levels did not differ between the groups in the fasting state, but cirrhotics showed a lower response to meals. Corresponding glucagon concentrations were greater in cirrhotics than in controls before and after meals throughout the 24-hour period (from -15 min to 24 hour: P less than 0.01). BAsal plasma somatostatin levels in the cirrhotic group were significantly higher than in control subjects (at -15 min and at 0 min: P less than 0.05) and further increased after meals. Plasma somatostatin was heterogeneous in normal and cirrhotic group, but the increase in its concentrations in patients with chronic liver disease was for the most part a consequence of elevations in the 1600 and 3500 molecular weight components. The half-life of exogenously infused somatostatin in cirrhotics was comparable to that of controls. These results indicate that in liver cirrhosis elevated levels of circulating somatostatin are associated with hyperglucagonemia and impaired insulin release. The high plasma somatostatin levels observed in cirrhotic patients are the result of hypersecretion of the D cell rather than impaired removal of the peptide.

Adult↗
PubMed1986

Chromosome 3q21 abnormalities associated with hyperactive thrombopoiesis in acute blastic transformation of chronic myeloid leukemia.

Two patients with acute blastic transformation of chronic myeloid leukemia (CML) associated with strikingly elevated platelet counts showed abnormalities of chromosome 3q in addition to the standard Philadelphia (Ph1) chromosome translocation. The first patient had an inversion of chromosome 3 (q21q26) cytologically identical to an inversion 3 previously reported in de novo acute megakaryoblastic leukemia, and the second patient showed a translocation between chromosome 3q and the chromosome 9 homologue not involved in the Ph1 translocation, [t(3;9)(q21;q34)]. Previous studies had incriminated either 3q21 or 3q26 as the locus for a regulatory thrombopoietic gene, but the current study suggests that 3q21 is the relevant site.

Adult↗
PubMed1985

Chorionic villus sampling for first trimester diagnosis of beta-thalassaemia. Report of the first South African case.

The first South African report of chorionic villus sampling for molecular diagnosis of beta-thalassaemia in a 10-weeks' pregnant Indian Muslim woman is presented. The sampling procedure and molecular techniques for sexing the fetus and establishing whether it was affected by beta-thalassaemia are described. From the sample of villi obtained a male fetus was identified, using an X-Y-specific DNA probe. A preliminary family study on both parents, the affected proband and his 4 phenotypically normal siblings, revealed two informative restriction fragment length polymorphisms in the mother, but none in the father. It was therefore not possible to differentiate between the two beta-globin gene alleles of the father. The fetus thus had a 50% chance of being a heterozygote or a 50% risk of being affected. Synthetic oligonucleotide hybridization of parental and fetal DNA was attempted by the Genetics Unit of Johns Hopkins Hospital, Baltimore, but the fetal hybridization was unsuccessful. Results on the parents were obtained too late to be of assistance in the present pregnancy as the parents requested termination of the pregnancy before 16 weeks' gestation for religious reasons.

Chorionic Villi↗
PubMed1985

The intracellular accumulation of UDP-N-acetylhexosamines is concomitant with the inability of human colon cancer cells to differentiate.

The relationship between the intracellular concentration of various nucleotides as measured by high-performance liquid chromatography analysis, and the differentiation of 2 human colon cancer cell lines was studied. HT-29 cells were induced to undergo both structural and functional enterocytic differentiation (as determined by electron microscopy and the presence of brush-border specific enzymes, respectively) by changing the carbon source or adding Na butyrate to standard tissue culture media. This differentiation occurred after the cells reached confluency when they were cultured in galactose, uridine, inosine, or without nucleosides (all in the absence of glucose) and in the presence of glucose plus Na butyrate. Cells cultured in 25 mM fructose or glucose +/- nucleosides did not differentiate. In all culture conditions where HT-29 cells did not differentite, the intracellular concentrations of 2 compounds which co-migrated with UDP-N-acetylglucosamine and UDP-N-acetylgalactosamine rose approximately equal to 10-fold at confluency and remained elevated throughout the stationary phase, whereas their concentrations remained constant and low after confluency in cells that underwent differentiation. This indicated that the accumulation of these compounds is associated with the inability of these cells to differentiate since other nucleotides and nucleotide sugars did not change in a similar fashion. Purification of the presumed UDP-N-acetylhexosamines, followed by the identification of the products from their chemical and enzymatic hydrolysis, confirmed the identity of these two peaks. Nucleotide analysis of Caco-2 cells, which undergo enterocytic differentiation after they reach confluency even when cultured on glucose, revealed the same pattern of UDP-N-acetylhexosamine levels as differentiated HT-29 cells, with its concentration remaining relatively constant and very low, even after the cells were confluent. The significance of the accumulation of UDP-N-acetylhexosamines in cells unable to differentiate is discussed.

Adenocarcinoma↗
PubMed1985

Enterocytic differentiation of a subpopulation of the human colon tumor cell line HT-29 selected for growth in sugar-free medium and its inhibition by glucose.

In order to study the effect of glucose on the differentiation of cultured human colon cancer cells, a subpopulation of HT-29 cells was selected for its capacity to grow in the total absence of sugar. These cells (Glc-cells) exhibit, after confluency, an enterocytic differentiation, in contrast to cells grown with glucose (Glc+ cells), which always remain undifferentiated. The differentiation is characterized by a polarization of the cell layer with apical brush borders and tight junctions, and by the presence of sucrase-isomaltase. The differentiation of Glc- cells is reversible: the addition of glucose to postconfluent cultures of Glc- cells results in an inhibiting effect on the expression of sucrase-isomaltase; switching growing cultures of Glc- cells to the Glc+ medium for several passages results in a progressive reversion to the undifferentiated state, which is completed after seven passages. The dedifferentiation process is associated with a parallel, passage-related, increase in the rates of glucose consumption and lactic acid production, and decreases of intracellular glycogen content, which return to the values of the undifferentiated original Glc+ cells. The values of these metabolic parameters are correlated, at each passage, with the degree of dedifferentiation of the cells. When these dedifferentiated cells, after having been cultured in Glc+ medium for 20 passages, are switched back to the Glc- medium, they readily grow without mortality, and reexpress the same enterocytic differentiation as the parent Glc- cells. These results show that the capacity of this subpopulation to grow and differentiate in the absence of sugar is a stable characteristic. They further suggest that glucose metabolism interferes with the program of differentiation of HT-29 cells.

Cell Differentiation↗
PubMed1985

Enterocytic differentiation and glucose utilization in the human colon tumor cell line Caco-2: modulation by forskolin.

The human colon cancer line Caco-2 exhibits after confluency a concomitant increase of glycogen accumulation and an enterocytic differentiation. The purpose of this work was to investigate whether forskolin (FK), an activator of adenylate cyclase, would induce a permanent glycogenolysis and, if so, whether it would result in modifications of the differentiation pattern of the cells. FK activates adenylate cyclase in Caco-2 cells with an ED50 of 7 X 10(-6)M. Three different treatment protocols with FK (10(-5)M) were applied: 1) the cells were treated during all the time in culture (20 days); 2) the treatment was started after confluency; 3) the treatment was interrupted after confluency. The presence of FK results in a permanent stimulation of cAMP accumulation (10 to 20 fold the basal values) and in a permanently reduced glycogen content (30 or 50% of the control values). The rates of glucose consumption are increased three and five fold in protocols 1 and 3 respectively. These metabolic changes are associated with morphological changes (tightening of the intercellular spaces and shortening of the brush border microvilli) and with a dual inhibition of the activities of brush border hydrolases: a) an inhibition of the post-confluent increase of activity of sucrase, aminopeptidase N and alkaline phosphatase in the brush border enriched fraction; b) an inhibition of the post-confluent increase of activity of sucrase in the cell homogenate. A comparison of the results obtained in each protocol shows that the morphological modifications and the decrease of the enzyme activities in the brush border fraction are regularly associated with an increased cAMP accumulation, whereas the inhibition of the differentiation of sucrase is a direct consequence of the increase in glucose consumption and decrease in glycogen stores.

Cell Line↗
PubMed1985

Short rib-polydactyly syndrome: a single or heterogeneous entity? A re-evaluation prompted by four new cases.

Four cases of lethal short rib-polydactyly syndrome (SRPS) from three non-consanguineous families are described. Radiological features were similar in all four cases and were most consistent with type III SRPS (Verma-Naumoff syndrome), but many differences in external and systemic abnormalities were noted. The considerable overlap of supposedly distinctive features displayed by the three main forms of SRPS is suggestive of a single locus mutation with variable expressivity, particularly for types I and III, possibly related to different mutant alleles and secondary intrauterine modification of the phenotype. All four cases showed anomalous sexual development. In spite of testicular differentiation in all four and a 46, XY karyotype in the two on whom chromosome studies were done, two infants were phenotypic females and two had ambiguous genitalia. A definitive diagnosis of SRPS was made at 26 weeks' gestation in a pregnancy at risk.

Chromosome Mapping↗
PubMed1985

Epithelial properties of human colonic carcinoma cell line Caco-2: effect of secretagogues.

Human colonic carcinoma Caco-2 cells grown in vitro form epithelial layers of highly polarized cells. Unlike colonic adsorptive cells they possess a mucosal membrane with very limited ionic conductance, even after exposure to aldosterone. When grown on filters, Caco-2 cells were sensitive to various secretagogues; these included 10(-5) M dibutyryl adenosine 3',5'-cyclic monophosphate (DBcAMP) and 10(-10) M vasoactive intestinal peptide, both of which, added serosally, enhanced the short-circuit current. The same applied to mucosal forskolin. Caco-2 cell sensitivity to serosal epinephrine was lower. Ion substitutions and 22Na-36Cl flux measurements indicated the possibility of secretagogue-dependent chloride secretion. Measurements on cells grown on Petri dishes and exposed to 1 mM DBcAMP for 1 h enabled detection of more profound modifications. Sustained 20-mV cell depolarization and a large reduction in the relative electrical resistance of the mucosal membrane were concomitant with a sizable decrease in 36Cl accumulation. These results suggest that Caco-2 cells, which to some extent resemble colonic crypt cells, possess the cAMP-dependent mucosal chloride conductance characteristic of secretory cells.

Bucladesine↗
PubMed1984

Aldosterone binding in the human colon carcinoma cell line HT29: correlation with cell differentiation.

The purpose of the present study is to investigate aldosterone binding to human colon carcinoma HT29 cells. These cells grow as undifferentiated epithelial cells when cultured under standard conditions (Dulbecco's MEM; 10% FCS). Modification of the culture medium induced two types of differentiation: (1) enterocytic differentiation when glucose (25 mM) is replaced by galactose (5 mM) (2) mucus secreting cells in FCS free medium. Aldosterone specific binding was detected in the cytosolic fraction of enterocyte-differentiated cells. This binding corresponded to a single class of sites with affinity, specificity and anion-exchange chromatographic behaviour similar to those observed in the epithelial crypts of human colon. These putative aldosterone receptors were also detected in mucus secreting cells that are derived from the enterocyte-differentiated cells. Enterocytic differentiation appears thus to be a necessary step for the "induction" of aldosterone receptors in HT29 cells.

Aldosterone↗
PubMed1984

Epithelial properties of human colonic carcinoma cell line Caco-2: electrical parameters.

Human colonic carcinoma Caco-2 cells grown in vitro undergo epithelial differentiation. Electrical measurements showed that they form resistant monolayers of polarized cells. On millipore filters, transepithelial electrical resistance (154 +/- 6.5 omega X cm2) was accompanied by a small potential difference (0.29 +/- 0.02 mV, serosal side positive) and by short-circuit current (1.9 +/- 0.14 microA X cm-2), both of which were ouabain sensitive. Micropuncture of domes formed on plastic supports under standard culture conditions revealed electrical polarity similar to that of filter-grown cells (0.8 +/- 0.2 mV, serosal side positive) combined with a highly negative cytoplasm (-57 +/- 1 mV) and very marked cell asymmetry (76% of total electrical cell resistance was located in the mucosal membrane). These parameters were not affected by the diuretic amiloride nor the hormone aldosterone, suggesting that sodium conductance is very limited in the mucosal membrane. Addition to the mucosal side of the ionophore nystatin or amphotericin B unmasked the possibility of high electrical transport activity. Electrical measurements made it possible to define the epithelial properties of Caco-2 cells, which may resemble those of colonic crypt or fetal cells. These measurements also confirmed that functional differentiation is homogeneous in Caco-2 cells. It is suggested that dome cell micropuncture may be useful in investigating the functional properties of other dome-forming cell lines.

Adenocarcinoma↗
PubMed1984

Metergoline in the management of normoprolactinemic secondary amenorrhea. A multicentric controlled trial.

In a multicentric study, the effect of the antiserotoninergic agent metergoline was evaluated in the management of patients with idiopathic normoprolactinemic secondary amenorrhea (NSA). The awareness that psychological factors might lead to a spontaneous reappearance of menses was also taken into account, and all the patients, after physical, gynecological and laboratory examinations, and the performance of the progesterone withdrawal bleeding test (100 mg i.m.) and the clomiphene citrate test (100 mg p.o./day for 5 days), were treated for 60 days with placebo; only patients showing no menses during placebo administration were later treated with metergoline. 108 patients entered the trial: of these, 48 experienced menses on admission or during placebo administration, and were withdrawn. Of the 60 patients not responding to placebo, 50 were treated for 90 days with metergoline (4 mg t.i.d.), and 23 had menses, ovulatory in 68.4% of cases. A new placebo treatment was accompanied, in the majority of cases, by recurrence of amenorrhea. These results indicate that many patients with NSA may experience a spontaneous disappearance of the disease: in cases more seriously affected metergoline might be a useful therapeutic agent.

Amenorrhea↗
PubMed1983

Sucrase-isomaltase: a marker of foetal and malignant epithelial cells of the human colon.

The presence of sucrase-isomaltase (SI), a glycoprotein hydrolase normally restricted to the brush border membrane of the enterocytes of the small intestine, was investigated in tumours which developed in nude mice inoculated with six human colon carcinoma cell lines (HT-29, Caco-2, HRT-18, HCT-8R, SW-480, and CO-115). Foetal and normal adult human small intestines and colons were used as controls. SI was studied by (1) immunofluorescence with rabbit antibodies raised against purified human small intestine SI; (2) polyacrylamide gel electrophoresis and immunoblotting; and (3) determination of the enzyme activity. SI was antigenically present, and enzymatically active, in all the tumours derived from Caco-2 and HT-29 cells. The presence of the enzyme was associated with that of typical brush borders at transmission electron microscopy examination. SI was absent from the tumours developed with the other four cell lines, as well as from the normal adult colon mucosa. SI was also present and active in the colons of mid-gestation foetuses, ranging in ages between 20 and 28 weeks; it was absent from the colons of late-gestation foetuses. The presence of SI in tumours derived from two cell lines suggests that this enzyme is a marker, so far unsuspected, of certain human colon cancers, and that the differentiation pattern of these particular cancers closely resembles that of the foetal colon.

Animals↗