PubMed Health⌕ Search

Biomedical subjects

A Diana

Publications and source records attributed to A Diana.

16 recordsLinked to original sources
PubMed1996

Lamin and beta-tubulin fragmentation precede chromatin degradation in glutamate-induced neuronal apoptosis.

During ischaemic brain injury, glutamate accumulation with overstimulation of postsynaptic glutamate receptors and intracellular Ca2+ overload lead to neuronal death. We have shown previously that delayed neuronal death in cultures of cerebellar granule cells (CGCs) exposed to glutamate occurs by apoptosis. Here, we report that lamin cleavage and dissolution of the microtubule network precede chromatin fragmentation in glutamate-induced CGC apoptosis. Like other events that characterize excitotoxic cell death, degradation of lamins, beta-tubulin and disruption of microtubule architecture is inhibited by the NMDA-receptor antagonist MK-801. Our findings suggest that cleavage of key cytoskeletal elements is an important step in glutamate-induced neuronal apoptosis.

Animals↗
PubMed1996

Nuclear pattern recognition by two-parameter texture analysis.

The present paper describes a simple procedure for the analysis of chromatin texture. High-resolution digitized images of nuclei are first standardized to render gray values invariant to staining and illumination conditions. Subsequently, the nucleus is subdivided by a square grid into 0.4 x 0.4 microns2 quadrats and standard deviations of gray values within each quadrat are estimated. Finally, the overall mean and standard deviation of quadrat standard deviations are calculated. These values may be considered as pure descriptors of the nuclear texture, as they represent the distribution of chromatin changes, disregarding any absolute densitometric and morphometric feature. Using the above descriptors it is possible to recognize at least seven chromatin patterns in a mixed population of developing and degenerating neurons. Results are visually verified by mapping the original pictures at the corresponding bivariate plot points. Comparison with the Markovian texture analysis is discussed.

Animals↗
PubMed1995

Adrenocortical apoptosis in hypophysectomized rats is selectively reduced by ACTH.

Using in situ end-labelling of DNA breaks (TUNEL) and staining with propidium iodide, we have investigated the occurrence of apoptosis in the adrenal cortex of hypophysectomized rats. Apoptosis was detected in the zona fasciculata and reticularis 3 days after hypophysectomy. Six days after hypophysectomy rats showed apoptotic cells mainly in the zona fasciculata. With the exception of the zona reticularis, cell death was largely prevented by ACTH replacement in 3-day hypophysectomized animals. The present results demonstrate that ACTH can reduce but not fully prevent apoptosis in the adrenal cortex of hypophysectomized rats and suggest that lack of other factors, such as other pituitary hormones, may be involved in the onset of apoptosis in the zona reticularis.

Adrenal Cortex↗
PubMed1995

Rhabdomyolytic acute renal failure in cardiac surgery. A clinical case.

OBJECTIVE: Authors describe 1 case of rhabdomyolytic acute renal failure as a complication of Cardiopulmonary bypass. EXPERIMENTAL DESIGN: Case report. SETTING: Department of Cardiac Surgery. INTERVENTIONS: Patient affected by rhabdomyolytic acute renal failure was treated with pharmacological therapy, plasmapheresis and continuous arteriovenous hemofiltration (CAVH). RESULTS: Anuric acute renal failure was diagnosed in 2nd post surgical day; serum myoglobin values was 16000 micrograms/l (normal values in non surgical patients < 88 micrograms/l), creatine phosphokinase serum values was 8790 UI/L (with Mb fraction < 8%). Patient underwent CAVH and two a day sessions of plasmapheresis; hematochemical and hemodynamic parameters improved progressively with resolution of acute renal failure and resumption of the diuresis on the 10th day. The CAVH was suspended on the 11th day and plasmapheresis on the 5th. Rhabdomyolytic syndrome should be correlated to the direct cannulation of the femoral artery for cardiopulmonary bypass and to prolonged time of extracorporeal circulation, with consequent leg ischemia/reperfusion induced injury which occurs during the extracorporeal circulation and continued during postoperative period; contributory causes should be the low cardiac output syndrome and alpha vasoconstrictor effect of high dose continuous intravenous administration of epinephrine. CONCLUSIONS: Rhabdomyolytic acute renal failure is a severe complication of cardiopulmonary bypass; plasmapheresis and continuous arteriovenous hemofiltration seems to be suitable treatments.

Acute Kidney Injury↗
PubMed1993

Nuclear patterns of apoptotic and developing neurons of superior cervical ganglion of newborn rat.

Superior cervical ganglion (SCG) neurons of female rats aged 3, 5 and 7 days revealed conspicuous nuclear changes in neurons undergoing postnatal cell death. Several qualitative and quantitative data such as nuclear size and shape, the presence of atypical chromocenters and chromatin textural features discriminated well neurons candidate to degeneration and those advancing in the direction of adult maturation. At least on morphological grounds, postnatal death of SCG neurons appears to be of apoptotic type. The sequence of nuclear events observed enables the recognition of the early stages of involution which prelude neuron degeneration.

Aging↗
PubMed1992

Immunohistochemical study of synaptophysin distribution in the superior cervical ganglion of newborn and adult rats.

Intense synaptophysin immunoreactivity was observed around neuronal cell bodies and in the neuropil of the superior cervical ganglion of adult rats. In newborn rats synaptophysin was comparatively less concentrated and restricted to small interstitial spaces. In contrast, in newborns, consistent traces of positivity were found in the Golgi-like area of larger neurons, in agreement with the higher neonatal rate of synaptophysin synthesis. A few clusters of small neurons, numerically more expanded in adult rats, exhibited a dense reaction product filling the whole cytoplasm. No positivity was found in intraganglionic fibres.

Aging↗
PubMed1991

Density profiles of biological specimens from Tiff files.

A program for achieving density profiles of Tiff images is described. Densitometric analysis is performed applying a cross-lateral averaging and longitudinal interpolation along the image axis. These procedures may be adapted to a variable axis curvature, length, width and morphological resolution. Since the Tiff format is supported by all desktop scanners and a large number of frame-grabbing devices, the range of applications includes the analysis of light and electron micrographs, autoradiograms, chromatograms, and data from any kind of bidimensional medium or flat surface. A special feature is the possibility of retrieving data from published pictures taken from literature.

Biology↗
PubMed1990

Substance P-like immunoreactivity in human prenatal hippocampal formation.

Presence and localization of substance P-like immunoreactive neuronal structures in human hippocampal formation during prenatal stages of ontogenesis are reported. In fetuses at 16 and 17 weeks of gestation immunoreactivity is very scarce and represented only by sporadic fibres in Ammon's horn and the entorhinal area. In specimens at 25 and 26 weeks of gestation, more or less intensely labelled perikarya of different morphology are easily detectable in deep layers of Ammon's horn and the hilus of fascia dentata. Immunoreactive beaded fibres are also present at this stage. The possibility of the existence of a substance P-containing extrinsic projection to Ammon's horn is pointed out.

Antibodies, Monoclonal↗
PubMed1990

Insulin supplement in type 2 diabetic patients with secondary failure to oral agents ameliorates hepatic and peripheral insulin sensitivity but not insulin secretion.

In order to investigate the mechanism of amelioration of metabolic abnormalities with supplementary doses of insulin, islet B-cell function and insulin sensitivity were measured in 10 patients with Type 2 diabetes in secondary failure to oral agents. A small dose of ultralente insulin (0.26 +/- 0.07 U kg-ideal-body-weight-1) was added in the morning before breakfast. After 3 months insulin therapy and progressive improvement of metabolic control (HbA1 from 10.5 +/- 0.4 to 9.0 +/- 0.3% at the end of insulin treatment, p less than 0.001), basal C-peptide and incremental area during an oral glucose tolerance test were unchanged. In vivo peripheral insulin sensitivity (euglycaemic clamp with insulin infusion of 40, 160, and 600 mU m-2 min-1, respectively) was significantly improved (glucose requirement: to 4.7 +/- 1.0 from 3.0 +/- 0.6 mg kg-1 min-1, p less than 0.05 at first insulin level; to 10.8 +/- 0.5 from 9.3 +/- 0.7 mg kg-1 min-1, p less than 0.01 at second level; to 13.3 +/- 0.6 from 11.8 +/- 0.8 mg kg-1 min-1, p less than 0.025 at third level). Basal hepatic glucose production was also significantly reduced (from 4.3 +/- 0.4 to 3.3 +/- 0.3 mg kg-1 min-1, p less than 0.05), and residual glucose production further suppressed after insulin supplement (from 1.1 +/- 0.4 to 0.3 +/- 0.2 mg kg-1 min-1 after 120 min at 100 mU l-1 plasma insulin, p less than 0.05). Specific insulin binding to mononuclear leucocytes was unchanged (from 3.1 +/- 0.3 to 3.5 +/- 0.3%, NS).

C-Peptide↗
PubMed1983

Family planning and female sterilization in the United States.

This report critically examines the issue of sterilization in the United States based on data from the National Survey of Family Growth, Cycles I and II, spanning the years 1973 to 1976. Of particular concern is analysis of sterilization rates as they vary across categories of race, socioeconomic status, welfare status, number of children and desire for the service. The development of a framework containing competing theories and philosophies, based upon previous literature in the area, provides a useful paradigm for an understanding of the significance of sterilization rates. The methodology includes bivariate techniques involving tabular analysis as well as multivariate techniques through the use of logistic regression analysis. Findings support hypotheses related to class factors and parity, while the racial and altruistic interpretations are not supported. Policy implications and areas requiring further research are specified.

Adolescent↗
PubMed1981

Insulin resistance in the aged: the role of the peripheral insulin receptors.

In the healthy subject, glucose tolerance tends to decrease with age due to impaired insulin secretion and/or decreased peripheral insulin activity. An oral glucose (100 g) tolerance test was performed on 12 aged (70 +/- 4 yr) and 8 young (32 +/- 7 yr) subjects; these subjects underwent laparatomy for cholecystectomy or the management of abdominal diseases. Subcutaneous adipose tissue was removed during surgery and fat cells, prepared according to a personal modification of Rodbell's method, were incubated in a medium containing monoiodo- and cold insulin to evaluate insulin binding and affinity constants. The results of the tolerance test pointed to an insulin resistant state i.e., impaired glucose tolerance coupled with normal plasma insulin, as previously shown also by us using other methods in the aged subject. The binding study demonstrates a distinct insulin receptor decrease in fat cells from the older subjects (185,000 +/- 19,200 as opposed to 310,000 +/- 12,000), without any change in affinity constants. The result indicates that insulin resistance in the aged may be attributed at least in part to a reduction in the number of insulin receptors on the target cells. This could be a consequence of aging itself, as proposed by other workers in the case of old fat rats.

Adipose Tissue↗
PubMed1975

Effects of a xanthine derivative (BL 191) on insulin secretion in normal man.

A xanthine derivative, named BL-191, was administered iv in 8 healthy volunteers alone and in association with glucose (0.33 g/kg body weight iv) or glybenclamide (1 mg iv). BL-191 was infused iv at a constant rate in a dose of 200 mg during 45 minutes. Blood glucose, free fatty acids and immunoreactive insulin were measured during one hour. It was impossible to demonstrate neither a direct effect nor an enhancement of insulin secretion during drug administration; in another experiment (treatment F) a higher dosage of BL-191 (100 mg as a priming dose + 200 mg as infusion dose) was likely ineffective. It appears that some difference in insulin response may be present in the single subject (not evident in the mean), indicating a difference in the beta-cell cAMP-system sensitivity in individuals. These negative results allow some considerations on the importance of the beta-cell cAMP-system in healthy human beings.

Adult↗
PubMedDate not supplied

Diurnal variations in insulin secretion and insulin sensitivity in aged subjects.

Glucose tolerance tends to decrease in healthy aged subjects without family history of diabetes. Either reduced insulin secretion or insulin resistance may be responsible. Insulin secretion and insulin sensitivity were studied in 7 aged subjects (68-75 years) and 8 young controls (21-27 years). A 1-mg i.v. glucagon and a 5-U/m2 body area i.v. insulin test were run in each subject at 07(00) and at 19(00) on two different days to detect diurnal variations. An arginine test was also performed to evaluate pancreatic glucagon behavior. In the evening, young subjects presented a glucose tolerance impairment with significantly decreased plasma insulin levels, and a reduced hypoglycemic effect of exogenous insulin. Resistance to both endogenous and exogenous insulin in the aged was observed in the morning without significant morning/evening variations. Since the response to contra-insular hormones (GH in the insulin test, glucagon in the arginine test) was the same in both age groups, their role in the phenomenon could be ruled out. It is suggested that in the aged a stable reduction in number and/or a change in affinity of insulin receptors may occur. In addition, since aging is seen to be associated with the disappearance of diurnal variations in glucose tolerance and insulin secretion and sensitivity, and since a reduction in the receptor level of young healthy subjects in the evening has been reported by some authors, it is suggested that aged subjects may be less able to modulate the binding of insulin to its peripheral receptors in the course of the day.

Adult↗
PubMedDate not supplied

[Immunological changes in diabetes mellitus. Study of lymphocyte populations].

In view of some data of the literature suggesting that immunological changes could play a role in the pathogensis of diabetes mellitus and of its complications, we carried out a study of the lymphocyte populations of 44 diabetic subjects by means of E, EA, EAC rosettes and membrane immunofluorescence. A quarter of the patients had decreased E rosettes: all of these had long-lasting, insulin-dependent, poorly controlled diabetes. Some of these patients had also increased membrane IgG globulins. In 5 patients with recent onset, insulin-independent diabetes, E rosettes were increased. No significant changes of EA and EAC rosettes were observed. These findings suggest that changes of lymphocyte populations do not play any role in the pathogenesis of diabetes, while these may be the consequence of the metabolic disorder and these may favour the onset of complications of the disease.

Adult↗