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Biomedical subjects

C Benedetti

Publications and source records attributed to C Benedetti.

At least 19 recordsLinked to original sources
PubMed1992

Evaluation of the accuracy of a pharmacokinetically-based patient-controlled analgesia system.

Bone marrow transplant patients having severe, prolonged oral mucositis pain (expected to last for one to three weeks) used a computer-controlled infusion system to self-administer morphine for pain control. Individual patient pharmacokinetic information, derived from a pretreatment bolus morphine dose, was used in a new bolus-elimination transfer algorithm to produce rapid adjustments of steady plasma morphine concentrations when the patient requested more or less drug. We evaluated the performance characteristics (bias and precision) of this pharmacokinetically based patient-controlled analgesic infusion system (PKPCA) in a group of 15 cancer patients over six to 14 days. Although we found a three- to fivefold pharmacokinetic variability in the tailoring morphine dose data, the PKPCA system was free of systematic bias (insignificant overall prediction error) during the patient-controlled infusions in this study population. The absolute prediction error was 19.9% for the group on the first study day and 25.6% over the entire study period (aggregate results; 6-14 days of continuous use). Two-thirds of the patients exhibited no bias throughout the study period, and individual bias in the others was symmetrically distributed (three patients with underpredictions and two overpredicted). Magnitude of prediction error during the patient-controlled morphine infusions was not related to the magnitude of pharmacokinetic deviation of individual subjects from group parameters. Our results indicate that this PKPCA system provides accurate control of plasma morphine concentration when used by patients to self-administer opioid for prolonged pain relief continuously over 1 to 2 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Analgesia, Patient-Controlled↗
PubMed1991

[Purification from goat antiserum of immunoglobulins against G6PD from rabbits].

DEAE Affi-Gel Blue (Bio-Rad) provides an efficient and rapid fractionation of human serum proteins by a single chromatographic step. When goat serum is applied to the matrix and chromatography is performed following the procedure utilized for the human serum proteins, the elution pattern changes and the Ig purification is not satisfactory. We achieved a better Ig purification from goat serum by the following improved procedure. We performed first an AS-40 fractionation followed by extensive dialysis in 50 mM Na-citrate pH 5.7. The sample was then loaded onto a P11 column equilibrated in the same buffer. The fraction eluted at Vo contained total IgG and the other serum proteins, except beta-globulins which were eluted with 0.24 M phosphate. Peak 1 concentrated and dialyzed in 20 mM phosphate buffer pH 8 was then applied to a DEAE Affi-Gel Blue column, equilibrated in the same buffer. Two protein peaks were eluted from this column and electrophoretically characterized as: peak 1, containing a pure Ig fraction (70% yield), peak 2 with albumin and other contaminating serum proteins. When goat antiserum is obtained against a specific protein, our technique may be suitably employed to purify polyclonal antibodies for immunoprecipitation studies.

Animals↗
PubMed1991

Pain, analgesia, and stress: an integrated view.

The different theories on the neuroanatomical substrate of pain have been revised in the frame of new concepts on the intercellular communication in the central nervous system. In fact, it has recently been proposed that two kinds of electrochemical transmission exist in the brain: the first one, called wiring transmission (WT), uses neuronal chains (neuronal plasma membranes and synaptic contacts), whereas the second one, called volume transmission (VT), uses the extracellular fluid as physical substrate. The old concept of a separate system of afferents and central cells that constitute the pain mechanism is no more longer tenable. To reach a better understanding of the psychophysiological basis of pain, we should consider a view where WT and VT cooperate within neuronal systems functionally affected by the pervading modulatory action of endocrine signals.

Analgesia↗
PubMed1990

[Hepatic hematopoiesis in phenylhydrazine-induced hemolytic anemia].

Ten adult rabbits were divided into two groups: the control rabbits, which received subcutaneous injections of 0.9% NaCl in three days; the experimental animals which received 3 mg/Kg body weight of phenylhydrazine (PHZ) subcutaneously also in three days. On the 8th day from the initial treatment the control and experimental animals were sacrificed, blood was collected to determine hematological parameters and livers were cut into small pieces. Sections were prepared by pressing the pieces onto slides which were stained with the Giemsa stain. The hematocrit and the reticulocytosis of experimental animals were 25 + 3%, and 70 + 5% respectively. In the liver sections of the PHZ treated animals we found a very rich population of immature erythroblasts. In fact proerythroblasts and basophilic erythroblasts were 19%, polychromatic and orthochromatic erythroblasts were 22% and 13% respectively. On the contrary, these cells were absent in the control livers. The lymphocyte and lymphoblast population, on the other hand, was very rich in control animals with a value of 38.8% compared to 1.62% in the anemic animals. The results clearly indicate the hematopoietic function of the liver in the anemic animals although the low percentage of orthochromatic erythroblasts with respect to their precursors suggests the ineffectiveness of the process.

Anemia, Hemolytic↗
PubMed1990

[Progression of the peripheral blood profile in phenylhydrazine-induced hemolytic anemia].

Male rabbits were made anemic by subcutaneous injections of 3 mg/Kg body weight of phenylhydrazine (PHZ) for the duration of three days. Blood samples were collected prior to the experiment, on the 2nd and 5th day from the end of the treatment. Hematocrit, reticulocyte count, MCV, osmotic resistance, RBC volume distribution curve and morphological analysis were performed on each sample in order to obtain a picture of the progressive changes of the parameters following the PHZ administration. Hematocrit values changed from 49 to 27%, whereas the reticulocytosis increased from 0.6 to 73%. A significant elevation of MCV was detected and the cell volume distribution curve, which presented the typical bell-shape profile in the normal animals became bimodal on the 5th day. The osmotic resistance of RBC of anemic animals, showed a marked deviation from the normal pattern. In fact initial haemolysis started at 0.75-0.70% NaCl concentration in the 5th day samples, while it was between 0.55-0.50% before the PHZ treatment. Finally, morphological analysis revealed a progressive increase of RBC with Heinz bodies, of macro-megalocytes and of immature erythroblasts thus indicating that the cell population, produced during recovery from PHZ induced anemia, is widely heterogeneous.

Anemia, Hemolytic↗
PubMed1987

Intraspinal analgesia: an historical overview.

The application of opioids in the proximity of the spinal cord is a recent addition to the forms of treatment available for pain relief. During the last 20 years we have learned more about the intimate mechanisms of the action of opiates then we had in the preceding 5 millennia. Opium, in fact, has been used for medical purposes from prehistoric times. On the basis of the newly acquired knowledge, we are now applying opioids in more effective ways and providing more patients with long overdue relief of their pain.

Analgesia↗
PubMed1985

Age-related changes in venous catecholamines basally and during epinephrine infusion in man.

Plasma epinephrine (EPI) and norepinephrine (NE) levels were examined among healthy men aged 20 to 25 and 60 to 65 years basally and during EPI infusions. On separate days, 14.3 and 42.9 ng/kg/min EPI was administered intravenously for 45 min. Although there was no age difference in venous EPI levels basally, the old had less increase during the EPI infusions. The plasma metabolic clearance rate of EPI was greater among the old men. Plasma NE levels were elevated among the elderly men, but both age groups had an increase in NE during the EPI 42.9 ng/kg/min infusion rate. During EPI infusions, the old men had less increase in systolic but not diastolic blood pressure or heart rate compared with the young men. The different pattern of change in venous EPI levels and increased metabolic clearance rate of EPI observed among the old men could, in part, explain diminished end-organ responsivity.

Adult↗
PubMed1984

[Changes in sweating during exertion. Effects of beta-blocker treatment].

Eccrine sweat secretion is studied during physical stress after the administration of a B-blocking agent: Butofilolol. 20 voluntary normotensive subjects, age 24 + 2 ans are submitted to 2 exercises stress test (ergometric bicycle) performed at on week interval. Butofilolol is administrated at a posology of 200 mg, 24 hours and 2 hours, before the test as well as placebo (double blind). Local sweat output is measured 1 min after stress and in the interscapulary region with an evaporimeter. Sweat weight, sweat electrolyte concentrations (sodium, chloride) are analysed from filters papers placed on the forehead. With butofilolol, significative increases of sweet output (+13%), sweat weight (+20%), and sodium (+20%), chloride (+26%) elimination are observed. The subjective observation of the effects of B-blocking agents is confirmed. The way of action of Butofilolol discussed.

Adrenergic beta-Antagonists↗
PubMed1984

Antidepressants in concomitant chronic back pain and depression: doxepin and desipramine compared.

Doxepin and desipramine at final doses of 188 and 173 mg/day, respectively, were compared in 36 volunteers with major affective or dysthymic disorder and chronic back pain. Both drugs produced significant decreases in depression, with an overall response rate of 70%; no significant difference was seen between groups. Pain ratings also decreased significantly in both groups (overall response rate = 50%); pain severity showed a better response to doxepin than to desipramine. While baseline pain, depression, and anxiety were correlated, treatment changes in these measures did not correlate. CSF beta-endorphin levels did not change with treatment. The usefulness of an antidepressant with anxiolytic properties, such as doxepin, is discussed.

Adult↗