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Biomedical subjects

C Galli

Publications and source records attributed to C Galli.

At least 217 records · Page 12Linked to original sources
PubMed1991

Somatic cells and the G2 to M-phase transition in sheep oocytes.

New protein synthesis is essential in sheep oocytes for the progression of the meiotic cycle to metaphase. Inhibition of transcription by alpha-amanitin, a specific inhibitor of RNA polymerase II, arrests meiosis in the G2 phase in cumulus enclosed oocytes but denuded oocytes progress to M-phase. Denuded oocytes injected with alpha-amanitin also undergo maturation. Cumulus-enclosed and denuded oocytes were also cultured on transcriptionally inactive follicle shells to examine the influence of transcription in the granulosa cell compartment on the progression of meiosis. No effect of alpha-amanitin was detected on the maturation rate of both cumulus enclosed and denuded oocytes. We conclude that transcription is required in the cumulus cells to allow translation of stored messages within the oocytes coding for cell-cycle proteins.

Amanitins↗
PubMed1991

[The noninvasive estimation of right atrial pressure improves the Doppler evaluation of the pulmonary systolic pressure].

The right ventricular systolic pressure can be evaluated with the Doppler method through the right ventricular-atrial gradient (RV-RA gradient) and the right atrial pressure. The former is expressed by the transtricuspid velocity of flow, the latter is generally assumed. In 50 patients with elevated pulmonary pressure we tested whether ultrasounds may be utilized for the evaluation of the right atrial pressure, and whether the derived values contribute to improve the accuracy of the method. We estimated the right ventricular systolic pressure with method A: RV-RA gradient + 10; and method B: RV-RA gradient x 1.1 + 14, where 10 and 14 are the assumed right atrial pressure (mmHg). Through the collapsibility index of the inferior vena cava, taken as an ultrasound-derived index of right atrial pressure, we were able to identify 3 groups of patients with normal (Group 1, 14 cases), elevated (Group 2, 21 cases) and moderately elevated (Group 3, 15 cases) right atrial pressure, respectively. In them the right ventricular systolic pressures obtained with both method A and method B were compared to those derived with catheter. In Group 1 the non-invasive values were significantly closer to the invasive ones when calculated with method A; the same was true of method B in Group 2. In Group 3 the accuracy of the 2 methods was similar. We conclude that ultrasound assists in the non-invasive approximation of the right atrial pressure as well as in the choice of the appropriate formula, so that Doppler estimation of the right ventricular systolic pressure is improved.

Adult↗
PubMed1991

Oviduct ampullary epithelium contributes a glycoprotein to the zona pellucida, perivitelline space and blastomeres membrane of sheep embryos.

Previous studies have identified a glycoprotein (sOP 92) that is secreted by sheep oviductal epithelium and subsequently becomes associated with developing embryos. The objective of this study was to more definitively demonstrate the localization of this protein in the oviductal epithelium of cycling ewes and in the embryos (developmental stage ranging between 1 and 8 cells) by using the light and electron microscopic immuno-gold techniques. In the oviduct, sOP 92 was present only in nonciliated cells of the ampulla but not in the isthmus. No major differences in signal intensity, in its organ or intracellular distribution were observed between the postovulatory and the luteal phase of the cycle. At the embryonic level, sOP 92 uniformly covered the surface of the zona pellucida and permeated its width. Moreover, the protein was present in the perivitelline space and on the blastomeres membrane but not in the cytoplasm or in the nucleus. These observations suggest that a marked regional difference in sheep oviduct secretions exists and confirm that there is a close association of these secretions with the developing embryos.

Animals↗
PubMed1991

Derivation of pluripotent, embryonic cell lines from the pig and sheep.

As previously described for the establishment of stable, pluripotent cell lines from pig blastocysts, an analogous cell line was isolated from a sheep blastocyst. There are common features in the morphologies and growth characteristics of the pig and sheep cells in culture; in particular, pig and sheep cells display large nuclei and relatively sparse cytoplasm, as is observed in mouse embryonic stem cells. Furthermore, the morphology of the sheep cells closely resembles that of cells in primary cultures of inner cell masses isolated immunosurgically from sheep blastocysts. This suggests that the sheep cell line represents a primary ectodermal lineage.

Animals↗
PubMed1991

Selection for necropsy: evaluation of 321 autopsied cases from 3041 consecutive deaths among residents of a defined geographical area.

By undertaking to act as 'medico necroscopo' (the medical doctors in charge of authorizing every burial) in the Unità Socio-Sanitaria Locale (USSL) 70, a region containing 92,500 inhabitants, we were able to collect over a four-year period (1985-88) information on 3371 deaths among residents of the area. Of these, 68.1% died at home, 12.6% in hospital with no autopsy, 9.5% in hospital with an autopsy and 9.8% outside of the USSL region. For the analysis, age, sex and leading cause of death were considered as explanatory variables and place of death and proportion of autopsied cases as the response variables. The factors found to be associated with deaths occurring in hospital were non-neoplastic (particularly cardiovascular and digestive) pathological conditions in patients under the age of 60. People with malignant neoplasms usually died at home, especially when they had a gastric or breast cancer. Factors associated with autopsy were: death at a young age, short length of hospitalization and death from a cardiovascular disease. Sex did not appear to play a direct role in selection for necropsy. Our results indicate that, in our and similar regions, the cases selected for autopsy form a subset that is so specific that any extrapolation to the total deceased population is misleading.

Adult↗
PubMed1991

Making arm movements within different parts of space: the premotor and motor cortical representation of a coordinate system for reaching to visual targets.

The activity of 156 individual arm-related neurons was studied in the premotor cortex (area 6) while monkeys made arm movements of similar directions within different parts of 3-dimensional space. This study was aimed at describing the relationship between premotor cortical cell activity and direction of arm movement and assessing the coordinate system underlying this relationship. We found that the activity of 152 (97.4%) cells varied in an orderly fashion with the direction of movement, in at least some region of the work space. Premotor cortical cells fired most for a given preferred direction and less for other directions of movement. These preferred directions covered the directional continuum in a uniform fashion across the work space. It was found that, as movements of similar directions were made within different parts of the work space, the cells' preferred directions changed their orientation. Although these changes had different magnitudes for different cells, at the population level, they followed closely the changes in orientation of the arm necessary to move the hand from one to another part of the work space. This shift of cells' preferred direction with the orientation of the arm in space has been observed with similar characteristics in the motor cortex (see Caminiti et al., 1990). In both premotor and motor cortices, neuronal movement population vectors provide a good description of movement direction. Unlike the individual cell preferred directions upon which they are based, movement population vectors did not change their spatial orientation across the work space, suggesting that they remain good predictors of movement direction regardless of the region of space in which movements are made. The firing frequency of both premotor and motor cortical neurons varied significantly with the position occupied by the hand in space. These static positional effects were observed in 88.5% of premotor and 91.8% of motor cortical cells. In a second task, monkeys made movements from differing origins to a common end point. This task was performed within 3 different parts of space and was aimed at dissociating movement direction from movement end point. It was found that in both premotor and motor cortices virtually all cells were related to the direction and not to the end point of movement. These data suggest that premotor and motor cortices use common mechanisms for coding arm movement direction. They also provide a basis for understanding the coordinate transformation required to move the hand toward visual targets in space.

Analysis of Variance↗
PubMed1990

Diets rich in n-9, n-6 and n-3 fatty acids differentially affect the generation of inositol phosphates and of thromboxane by stimulated platelets, in the rabbit.

We have studied the effects of semi-synthetic diets rich in either n-9 (olive oil, OO) or n-6 (corn oil, CO), or n-3 (fish oil, FO, as MaxEPA) fatty acids on the levels of major PUFA in platelet lipids, on the generation of inositol phosphates by [3H]inositol labelled platelets after stimulation with thrombin and of thromboxane B2 (TxB2) by platelet rich plasma (PRP) after stimulation with collagen. The predicted elevations of oleic (OA), linoleic (LA) and eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids were observed in platelet lipids of each animal group, but in the MaxEPA fed group accumulation of EPA was associated with depletion of linoleic acid (LA) rather than of arachidonic acid (AA). Basal levels of inositol-tris-phosphate (IP3) in platelets were lowest in the OO group and highest in the CO group, whereas the increment after thrombin stimulation (1 unit/ml NIH) was maximal in the OO group and minimal in the FO group. Instead, when generation of TxB2 by stimulated platelets was evaluated, no appreciable difference among the various groups could be detected, in accordance with the limited modifications of platelet AA content induced by the diets. The overall data indicate that dietary fatty acids modulate the pathway of inositol phosphate generation in rabbit platelets, independently of modifications of TxB2 production.

Animals↗
PubMed1990

Shift of preferred directions of premotor cortical cells with arm movements performed across the workspace.

The activity of 156 neurons was recorded in the premotor cortex (Weinrich and Wise 1982) and in an adjoining rostral region of area 6 (area 6 DR; Barbas and Pandya 1987) while monkeys made visually-guided arm movements of similar direction within different parts of space. The activity of individual neurons varied most for a given preferred direction of movement within each part of space. These neurons (152/156, 97.4%) were labeled as directional. The spatial orientation of their preferred directions shifted in space to "follow" the rotation of the shoulder joint necessary to bring the arm into the different parts of the work-space. These results suggest that the cortical areas studied represent arm movement direction within a coordinate system rotating with the arm and where signals about the movement direction relate to the motor plan through a simple invariant relationship, that between cell preferred direction and arm orientation in space.

Animals↗
PubMed1990

Dietary n-9, n-6, and n-3 fatty acids modify linoleic acid more than arachidonic acid levels in plasma and platelet lipids and minimally affect platelet thromboxane formation in the rabbit.

We have studied the effects of semisynthetic diets containing 5% by weight (12% of the energy) of either olive oil (70% oleic acid, OA) or corn oil (58% linoleic acid), or fish oil (Max EPA, containing about 30% eicosapentaenoic, EPA C 20:5 n-3, plus docosahexaenoic, DHA C 22:6 n-3, acids, and less than 2% linoleic acid), fed to male rabbits for a period of five weeks, on plasma and platelet fatty acids and platelet thromboxane formation. Aim of the study was to quantitate the absolute changes of n-6 and n-3 fatty acid levels in plasma and platelet lipid pools after dietary manipulations and to correlate the effects on eicosanoid-precursor fatty acids with those on platelet thromboxane formation. The major differences were found when comparing the group fed fish oil and depleted linoleic acid vs the other groups. The accumulation of n-3 fatty acids in various lipid classes was associated with modifications in the distribution of linoleic acid and arachidonic acid in different lipid pools. In platelets maximal incorporation of n-3 fatty acids occurred in phosphatidyl ethanolamine, which also participated in most of the total arachidonic acid reduction occurring in platelets, and linoleic acid, more than archidonic acid, was replaced by n-3 fatty acids in various phospholipids. The archidonic acid content of phosphatidyl choline was unaffected and that of phosphatidyl inositol only marginally reduced. Thromboxane formation by thrombin stimulated platelets did not differ among the three groups, and this may be related to the minimal changes of arachidonic acid in phosphatidyl choline and phosphatidyl inositol.

Journal Article↗
PubMed1990

Hemodynamic and renin responses to nifedipine in renovascular hypertension.

We investigated the acute effects of nifedipine (10 mg orally) on renin and systemic hemodynamics in twelve patients who had severe hypertension (diastolic values averaging 114 mm Hg) with unilateral renal artery stenosis (angiography) and hyperreninemia. Plasma renin activity was determined from blood samples drawn from the aorta and from both renal veins, so that "ischemic lateralization" could be evaluated through appropriately derived indexes. Nifedipine promptly and significantly lowered aortic pressure in all patients. At 30 minutes maximal circulatory responses were recorded, which consisted of a 22% decrease in mean aortic pressure (from an average of 144.6 +/- 15 mm Hg to an average of 113 +/- 11 mm Hg), a 44% reduction of systemic vascular resistance (from 2162 +/- 540 dynes.sec.cm-5 to to 1205 +/- 279 dynes.sec.cm-5), a 33% rise in cardiac index (from 2920 +/- 970 ml/min/m2 to 3875 +/- 986 ml/min/m2). These effects were still evident, although somewhat tempered, after 180 minutes of continuous monitoring; they were qualitatively and quantitatively similar to those reported by some authors in persons with primary hypertension with similar levels of blood pressure. After nifedipine was given, renin activity of the systemic blood rose significantly, because of a potentiated release from the kidney with arterial stenosis. This effect, which was inferred as being due to further reduction of the renal perfusion pressure, improved the significance of "ischemic lateralization" indexes and supported the diagnosis of renovascular hypertension in all cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Dietary fatty acids, serum lipids, platelet biochemistry and function.

Dietary fatty acids of the n-6 mainly linoleic acid (LA) series, and of the n-3, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) series both reduce plasma cholesterol levels and platelet responses to aggregating agents. The potency of n-3 fatty acids, which are present in relatively high concentrations in fish oils, is at least one order of magnitude greater than that of LA. The effects of fish oils appear to be related to the incorporation of EPA into plasma lipoproteins and cell phospholipid pools, thus modulating metabolic processes within specific lipid pools. Inhibition of platelet function and modifications of the activity of other blood cells, such as leukocytes, is attributed to interference with the eicosanoid system. Competition of EPA with arachidonic acid (AA) for the oxygenases and/or generation of less active metabolites from this precursor are the major mechanisms of action. Feeding studies in experimental animals indicate that exogenously administered n-3 fatty acids undergo distribution among the major plasma lipid classes and platelet phospholipids quite different to that of endogenous AA. In addition, the generation of inositolphosphates by stimulated platelets is decreased by dietary n-3 fatty acids in a manner independent of the effects on the eicosanoid system. It appears that polyunsaturated fatty acids (PUFA) of the n-6 and n-3 series are differently handled in various lipid pools and that early steps of cell activation, in addition to the generation of eicosanoids, are affected by dietary fatty acids. This indicates that fatty acids modulate key steps in the regulation of cell function and biochemistry.(ABSTRACT TRUNCATED AT 250 WORDS)

Arteriosclerosis↗