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Biomedical subjects

M Montana

Publications and source records attributed to M Montana.

52 records · Page 3Linked to original sources
PubMed1995

Platelet membrane fluidity and platelet membrane lipid pattern in essential hypertension.

In a group of subjects with essential hypertension platelets were studied in resting conditions: platelet membrane fluidity was measured with the fluorescent probe 1.4-(trimethylamino)-phenyl-4-phenylhexatriene (TMA-DPH), platelet membrane cholesterol/phospholipid ratio was evaluated separating the membrane lipids with column chromatography, and platelet membrane individual phospholipids were determined using two-dimensional thin-layer chromatography. From the obtained results, it is evident that platelet membrane fluidity does not differentiate normals from hypertensives; platelet membrane cholesterol/phospholipid ratio is increased in hypertensives, while of the platelet membrane individual phospholipids, only the phosphatidylcholine is increased. In normals and hypertensives, no relation is evident between platelet membrane fluidity, platelet membrane lipid pattern, and systolic and diastolic blood pressure values.

Adult↗
PubMed1995

Cytosolic Ca2+ content and membrane fluidity of platelets and polymorphonuclear leucocytes in diabetes mellitus.

Considering the role played by platelets and leucocytes in diabetic disease and keeping in mind the strong correlation between functional and metabolic aspects that characterizes this clinical condition, we evaluated, in two groups of diabetics, respectively the platelet and polymorphonuclear (PMN) cytosolic Ca2+ content (employing the fluorescent probe Fura 2-AM) and membrane fluidity (using the fluorescent probe TMA-DPH and considering the fluorescence polarization degree, inversely related to the membrane fluidity). From the obtained results, it is evident that the platelet cytosolic Ca2+ content does not distinguish normals from diabetics of type 1 and 2; the platelet membrane fluidity instead does not discriminate normals from diabetics, but differentiates diabetics of type 1 and 2 (type 1 = 0.284 +/- 0.015; type 2 = 0.314 +/- 0.018; p < 0.001). PMN cytosolic Ca2+ content and membrane fluidity do not discriminate normals from diabetics. In the two groups of diabetics none of the platelet and PMN parameters (cytosolic Ca2+ content and membrane fluidity) are related to the glycometabolic pattern.

Adolescent↗
PubMed1995

Membrane fluidity, membrane lipid pattern, and cytosolic Ca2+ content in platelets from a group of type II diabetic patients with macrovascular complications.

OBJECTIVE: To evaluate platelet membrane fluidity and some platelet metabolic parameters in type II diabetic patients with macrovascular complications. RESEARCH DESIGN AND METHODS: In a group of 21 type II diabetic patients with macrovascular complications, we evaluated platelet membrane fluidity [marking intact resting platelets with the fluorescent probe 1,4-(trimethylamino)-phenyl-4-phenylhexatriene (TMA-DPH)], platelet membrane lipid pattern (cholesterol:phospholipid [C:PL] ratio and individual phospholipids), and platelet cytosolic Ca2+ content (marking intact resting platelets with the fluorescent probe Fura 2AM). RESULTS: Platelet membrane fluidity is decreased in type II diabetic patients with macrovascular complications compared with normal subjects (P < 0.001). Platelet membrane C:PL ratio and cytosolic Ca2+ content do not discriminate normal subjects from diabetic patients, and for individual phospholipids, only phosphatidylethanolamine is decreased in diabetic patients compared with control subjects (P = 0.051). In normal subjects, the polarization degree of TMA-DPH is related to phosphatidylserine (P < 0.05) and phosphatidylcholine (P < 0.05), and in diabetic patients the polarization degree of TMA-DPH is related to C:PL ratio (P < 0.05) and sphyngomyelin (P < 0.05). CONCLUSIONS: In type II diabetic patients with macrovascular complications, we observed an abnormality of platelet membrane fluidity, which may contribute to platelet functional alteration present in this clinical condition.

Aged↗
PubMed1995

[Plasma, erythrocyte and platelet magnesium in essential hyperTension, diabetes mellitus without and with macrovascular complications and atherosclerotic vascular disease].

In 4 groups of subjects with different clinical conditions: essential hypertension, diabetes mellitus without and with macrovascular complications, vascular atherosclerotic disease (VAD), we evaluated the plasma, erythrocyte and platelet magnesium content, the correlations between them and the relationships among all these parameters and metabolic and haemodynamic determinants. From the obtained data, it is evident that platelet magnesium content is decreased in hypertensives and in type 2 diabetics with macrovascular complications, and in subjects with VAD, while the red cell magnesium content in VAD subjects and in type 2 diabetics with macrovascular complications is increased; in type 1 diabetics we observed a decrease of the plasma magnesium level. The relationships between the plasma and cellular magnesium content, in the different clinical conditions, seem interesting.

Adult↗
PubMed1994

Prolonged presence of isoxsuprine in equine serum after oral administration.

1. Isoxsuprine [1-(4-hydroxyphenyl)-2-(1-methyl-2-phenoxyethylamino)-1- propanol] serum concentrations after single- and multiple-dose administration to horse were investigated using immunoenzymatic ELISA, HPLC-UV and thermospray HPLC-MS methods. 2. Using HPLC-MS, isoxsuprine was detected up to 72 h after a single administration (1.2 mg/kg by gastric probe) and up to 96 h after the end of serial administration (1.2 mg/kg every 12 h for 7 days). 3. ELISA detected the drug up to 96 h after a single dose and up to 6 days after the end of prolonged administration. 4. Isoxsuprine is present in horse serum almost totally in conjugated form very likely as glucuronide. 5. It is concluded the administration of this drug must be suspended much earlier than previously presumed if race horse antidoping tests for the drug are to be negative.

Administration, Oral↗
PubMed1993

Toxicokinetics and metabolism of linuron in rabbit: in vivo and in vitro studies.

1. Linuron (N'-(3,4-dichlorophenyl)-N-methoxy-N-methylurea) metabolism and kinetic behaviour were investigated after oral and i.v. administration to six New Zealand White female rabbits. 2. After i.v. dosage, linuron distributes quickly and widely to peripheral tissues and its is rapidly eliminated; rapid absorption was also observed after oral administration of the herbicide which undergoes extensive first pass metabolism in the liver. 3. The major metabolites obtained from both in vivo (serum samples) and in vitro (microsomal fractions incubated with linuron) experiments were identified by h.p.l.c.-mass spectrometry as N'-(3,4-dichlorophenyl)-N-methoxyurea, N'-(3,4-dichlorophenyl) urea, and N'-(6-hydroxy-3,4-dichlorophenyl) urea. 4. Given the common metabolites reported in rat and rabbit, and the fact that linuron is a liver enzyme inducer in rat, it may be possible that linuron also induces the P450 system in rabbit. Hence, despite the low acute toxicity of linuron in rabbit, the intake of hay and feed contaminated by the herbicide could be a health risk for these breeding animals since it could modify the effectiveness of many drugs commonly used in veterinary practice and metabolized by the same liver enzymes.

Administration, Oral↗
PubMed1991

Effect of a bulk-forming cathartic on diarrhea in tube-fed patients.

Diarrhea is a significant complication for the patient being tube-fed. The purpose of this study was to observe whether giving a bulk-forming cathartic to patients receiving enteral nutrition via nasogastric or nasoduodenal tube would result in firmer stools for these patients. Forty-nine patients in a large medical center were randomly assigned to either a control or an experimental group. During the 6-day study period 1 teaspoon (5 ml) of psyllium preparation was administered through the feeding tube three times a day. Data were analyzed by using the Mann-Whitney U test for nonparametric data. The hypothesis that giving a bulk-forming cathartic would lead to firmer stools was supported at an alpha level of less than 0.01. The results of this study suggest that use of a bulk-forming cathartic in tube-fed patients will significantly reduce the diarrhea associated with this type of feeding.

Administration, Oral↗
PubMedDate not supplied

CT findings of metastatic breast carcinoma involving muscle.

Hematogenous metastatic disease to skeletal muscle is a very unusual occurrence and is seldom diagnosed clinically. This case report demonstrates the CT findings of metastatic breast cancer to skeletal muscle of the neck.

Breast Neoplasms↗
PubMedDate not supplied

Deep venous thrombosis: leukocyte rheology at baseline and after in vitro activation.

We evaluated leukocyte rheology, expressed as leukocyte filtration, polymorphonuclear (PMN) membrane fluidity and cytosolic Ca2+ concentration in subjects with acute deep venous leg thrombosis (DVT). In 14 subjects with leg DVT we examined the leukocyte filtration [unfractionated, mononuclear cells (MN), PMNs], PMN membrane fluidity and PMN cytosolic Ca2+ concentration. Subsequently, we evaluated the same PMN variables after in vitro chemotactic activation with 4-phorbol-12-myristate-13-acetate. At baseline, we observed a significant difference in the filtration of unfractionated and MNs and in PMN cytosolic Ca2+ concentration. After PMN activation, a significant variation, greater in DVT subjects, was present in PMN filtration at 5 and 15 min. In normals, no variation was present in PMN membrane fluidity or cytosolic Ca2+ concentration after activation, while in subjects with DVT we found a significant variation in both PMN parameters. These results underline that there is a systemic leukocyte functional alteration in DVT.

Adult↗
PubMedDate not supplied

Erythrocyte individual phospholipids and erythrocyte membrane fluidity in subjects with vascular atherosclerotic disease with and without diabetes mellitus of type 2.

In a group of 12 subjects (5 men, 7 women) with vascular atherosclerotic disease (VAD) and in a group of 17 subjects (9 men, 8 women) with VAD and with non-insulin dependent diabetes mellitus (NIDDM) we evaluated the red cell membrane individual phospholipids and their relationships with the erythrocyte membrane fluidity. Examining the group of non diabetic subjects with VAD, it is evident that no difference is present between normals and this group regarding individual phospholipids; in this group is present a slight correlation between the erythrocyte membrane fluidity (expressed as Iex/Im ratio) and phosphatidylethanolamine only. Examining the group of VAD subjects with NIDDM it is evident that between normals and this group a significant difference is present for phosphatidylcholine and phosphatidylserine; in this group no relationship is evident between red cell membrane individual phospholipids and Iex/Im ratio.

Aged↗
PubMedDate not supplied

Exercise test: trend of the leukocyte flow properties, polymorphonuclear membrane fluidity and cytosolic Ca2+ content in normals, in subjects with previous acute myocardial infarction and in subjects with aortocoronary by-pass.

We evaluated, during an exercise test, the leukocyte flow properties, the polymorphonuclear leukocyte (PMN) membrane fluidity and PMN cytosolic Ca2+ content in normals, in subjects with previous acute myocardial infarction (AMI) and in subjects previously submitted to a aortocoronary by-pass. Leukocyte flow properties were evaluated using the St. George filtrometer. Examination of the PMN membrane fluidity was effected employing the probe TMA-DPH; while evaluation of the PMN cytosolic Ca2+ content was carried out using the probe Fura 2-AM. At baseline, in both cardiopathic groups a significant difference in PMN filtration parameters and in PMN cytosolic Ca2+ content was evident compared to normals. In normals, at peak of exercise, there was an evident reduction of mononuclear filtration parameters, while during recovery a slight increase of the PMN cytosolic Ca2+ content was observed. In subjects with previous AMI and in subjects with aortocoronary by-pass, however, we observed, at peak of exercise, a decrease of the mononuclear filtration parameters, a reduction of the PMN membrane fluidity and an increase of the PMN cytosolic Ca2+ content. In both groups, the changes in PMN membrane fluidity and cytosolic Ca2+ content remained during recovery. The trend of the PMN membrane fluidity and cytosolic Ca2+ content found in the cardiopathic subjects during the exercise test suggest the PMN activation may be more evident in these subjects.

Adult↗
PubMedDate not supplied

Polymorphonuclear leukocyte membrane fluidity and cytosolic Ca2+ content in different clinical conditions.

The aim of the study was to evaluate the polymorphonuclear leukocyte (PMN) membrane fluidity and PMN cytosolic Ca2+ content in several clinical conditions: diabetes mellitus, vascular atherosclerotic disease (VAD), chronic renal failure (CRF), essential hypertension (EH). In 13 subjects with insulin-dependent diabetes mellitus (IDDM), in 24 subjects with non-insulin-dependent diabetes mellitus (NIDDM), in 42 VAD subjects, in 23 VAD subjects with NIDDM, in 15 subjects with CRF and in 12 subjects with EH, we determined the PMN membrane fluidity, obtained marking unstimulated PMN cells with fluorescent probe 1-[4-(trimethylamino)phenyl]-6-phenyl-1,3,5-hexatriene (TMA-DPH), and considering the fluorescence polarization degree, and the PMN cytosolic Ca2+ content, obtained marking unstimulated PMN cells with the fluorescent probe Fura2-AM and considering the ratio between the Fura2-Ca2+ complex and the unchelated Fura 2 fluorescence intensity. From the obtained data it is evident that PMN membrane fluidity does not distinguish normals from IDDM subjects, NIDDM subjects, VAD subjects with and without NIDDM, CRF subjects and hypertensives. PMN cytosolic Ca2+ content, in comparison with normal controls, is significantly increased in VAD subjects (p < 0.01), in VAD subjects with NIDDM (p < 0.001), in CRF subjects (p < 0.001) and in hypertensives (p < 0.05). No correlation was found between PMN membrane fluidity and PMN cytosolic Ca2+ content. The study of these PMN parameters can be useful in the understanding of the role of leukocytes in the vascular damage that characterizes these clinical conditions.

Adolescent↗
PubMedDate not supplied

Behavior of the polymorphonuclear leukocyte membrane fluidity and cystolic Ca2+ content in vascular atherosclerotic disease with and without non-insulin-dependent diabetes mellitus.

In 71 subjects with vascular atherosclerotic disease (VAD), in 32 VAD subjects with non-insulin-dependent diabetes mellitus (NIDDM) and in 31 normal controls, we evaluated polymorphonuclear leukocyte (PMN) membrane fluidity and PMN cytosolic Ca2+ content. The PMN membrane fluidity was obtained by marking intact and unstimulated PMN cells with fluorescent probe 1-[4-(trimethylamino)phenyl]-6-phenyl-1,3,5-hexatriene (TMA-DPH) and the PMN cytosolic Ca2+ content was obtained by marking intact and unstimulated PMN cells with the fluorescent probe Fura 2-AM. From the obtained results, it is evident that PMN membrane fluidity does not differentiate normals from VAD subjects and VAD subjects with NIDDM, and normals from subjects with monovascular disease (MVAD) and polyvascular disease (PVAD) with and without NIDDM. The PMN cytosolic Ca2+ content is significantly increased in VAD subjects and VAD subjects with NIDDM, and also in MVAD and PVAD subjects with and without NIDDM. A positive correlation is present between PMN membrane fluidity and PMN cytosolic Ca2+ content in normals and VAD subjects, but not in VAD subjects with NIDDM. In conclusion, in VAD subjects with and without NIDDM, an increase of the PMN cytosolic Ca2+ content is present; this increase might be related to the PMN spontaneous activation.

Aged↗