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R Dorizzi

Publications and source records attributed to R Dorizzi.

33 records · Page 2Linked to original sources
PubMed1990

Non-extraction HPLC method for simultaneous measurement of dyphylline and doxofylline in serum.

A direct injection HPLC method for the simultaneous measurement of dyphylline and doxofylline in serum is reported. Chromatography is carried out with a "Pinkerton" internal surface reversed-phase column and phosphate buffer (0.1 mol/L, pH 6.8) as mobile phase. Absorbance at 275 nm is monitored. Only 10 microL of serum is required to detect less than 1 mg of each drug per liter in biological samples. The standard curve for the method is linear over the range 6-100 mg/L, and precision is acceptable for both drugs, with CVs of 2% and 1.5% for respective concentrations of 6.2 and 25 mg/L. None of the 76 drugs tested for interference affected the measurement of either drug. Four samples can be injected per hour. This method provides a fast, accurate way to monitor two interesting therapeutic agents used in chronic obstructive airway diseases.

Chromatography, High Pressure Liquid↗
PubMed1989

High-performance liquid chromatographic determination of morphine in biological samples: an overview of separation methods and detection techniques.

High-performance liquid chromatogrpahy with electrochemical detection at present suits most of the needs of toxicologists for the determination of morphine and some related compounds in biological samples, although fluorescence detection is still a useful alternative. Chemiluminescence detection may be promising, but needs further optimization of its coupling with HPLC to give the best performances. Morphine detection by absorbance spectrophotometry does not seem to allow the degree of sensitivity and selectivity from matrix interferences that is required in most instances. However, this approach is useful when morphine congeners undetectable by alternative means (i.e., heroin and morphine-3-glucuronide) are to be determined or when a general toxicological screening is required.

Chromatography, High Pressure Liquid↗
PubMed1987

The acute-phase response after bisphosphonate administration.

In patients who have never previously received bisphosphonate therapy, the intravenous administration of 4-amino-1-hydroxybuthilidene-1,1-bisphosphonate (AHButBP), 3-amino-1-hydroxypropylidene-1,1-bisphosphonate (AHPrBP), or 6-amino-1-hydroxyhexylidene-1,1-bisphosphonate (AHHexBP) induced an acute-phase response (APR) irrespective of the underlying disease, manifested by a fall in circulating lymphocyte number and serum zinc concentration and in a rise in C-reactive protein (CRP); a febrile reaction occurred in 30% of the patients. The APR was maximally expressed within 28-36 hours of i.v. administration of the bisphosphonates and disappeared 2-3 days later despite continuous treatment. These effects were dose dependent and the lowest doses necessary for an APR were 10 mg of AHButBP and AHPrBP and 75 mg of AHHexBP. Doses up to 1,000 mg/day i.v. of dichloromethanebisphosphonate (Cl2MBP) were devoid of these side effects. In patients treated with either a single i.v. dose of amino-bisphosphonates which resulted in an APR or with a suboptimal dose, a subsequent challenge 12-160 days later of the high dose failed to cause a rise in CRP or a fall in the lymphocyte count. The desensitization to AHButBP or AHPrBP was also seen following pretreatment with Cl2MBP. These findings suggest that bisphosphonates interact with macrophage-like cells resident in the skeleton and stimulate interleukin-1 release which is responsible for the appearance of the APR. At the same time, however, the bisphosphonates render these cells insensitive to further stimulation for several months.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute-Phase Reaction↗
PubMed1986

Parathyroid hormone, calcitonin and vitamin D metabolites in beta-thalassaemia major.

Serum calcium (Ca), phosphorus (P), alkaline phosphatase (Al-P), parathyroid hormone (PTH), calcitonin (CT), 25-hydroxyvitamin D3 (25OHD3), 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) levels and urinary excretion of Ca, P, hydroxyproline (OH-P) and cyclic AMP (cAMP) were determined in summer and in winter in 13 thalassaemic children (7 aged 3-5 years-group 1-; and 6 aged 10-13 years-group 2-), who had never taken vitamin D supplements or therapy, and in two groups of 14 controls of the same age. In thalassaemics of group 1 only serum Al-P levels and OH-P urinary excretion were higher than in controls (P less than 0.01). In thalassaemics of group 2 Ca (P less than 0.05), P (P less than 0.05), PTH (P less than 0.001), CT (P less than 0.001), 25OHD3 (P less than 0.05), 1,25(OH)2D3 (P less than 0.001) levels and cAMP urinary excretion (P less than 0.001) were lower, whereas Al-P (P less than 0.001) and CT (P less than 0.001) levels and urinary excretion of P (P less than 0.05) and of OH-P (P less than 0.001) were higher than in controls, both in summer and in winter. Advancing age induces in thalassaemic patients a decrease in PTH secretion and a consequent deficit in synthesis of 1,25(OH)2D3 that may explain some aspects of bone changes, which CT hypersecretion may tend to counteract.

Adolescent↗
PubMed1985

Liquid chromatography with pre-column dansyl derivatisation and fluorimetric detection applied to the assay of morphine in biological samples.

A simple method employing pre-column dansylation and liquid chromatography is proposed for a very sensitive and specific assay of morphine in biological samples. Nalorphine is used as an internal standard. The detection limit is 0.2 picomol of injected morphine. In the assay of human sera spiked with 150 nmol/l, the intra- and inter-assay coefficients of variation were 3.7% (n = 10) and 4.5% (n = 10), respectively. No interferences were observed from more than 70 opiate and non-opiate drugs. Urine, plasma and total blood were assayed, using different extraction methods, with negligible interference from coextractives.

Chromatography, High Pressure Liquid↗
PubMed1985

Calcitonin serum levels in heroin addicts: effects of methadone and clonidine detoxication treatments.

Calcitonin (CT), a 32-aminoacid peptide, is secreted by the parafollicular 'C' cells of the thyroid which derive from the ultimobranchial body and, ultimately, from the neural crest. In man, the main role of this hormone is to protect the skeleton during periods of physiological stress, such as growth, pregnancy and lactation by reducing calcium loss [1]. Nevertheless, some recent data, such as the finding of immunoreactive CT-like material (iCT) in the central nervous system [2] and in the cerebrospinal fluid and the demonstration of its analgesic action in rabbits [4] and in man [5] indicate a relationship between CT and the neuroendocrine system. The purpose of the present study is to evaluate the levels of CT in a group of addicts to heroin both before and during detoxication treatment with methadone or a non-opioid drug like clonidine.

Adolescent↗
PubMed1985

Dichloromethylene-diphosphonate in patients with prostatic carcinoma metastatic to the skeleton.

A total of 17 patients with multiple osteoblastic bone metastases owing to prostatic carcinoma was treated with 2-dichloromethylene-diphosphonate, a powerful inhibitor of bone resorption. The drug was given intravenously (300 mg.) for 2 weeks and then orally (3,200 mg.) or intramuscularly (100 mg.) for 4 to 11 weeks. A definite improvement in pain, assessed by daily consumption of analgesic drugs and by an analogic scale, was observed within 10 days in 16 of the 17 patients. Four patients confined to bed rest for pain were able to walk after 2 weeks and reversal of paralysis also was noted in 1 patient. Transient changes in serum calcium (decreasing) and alkaline phosphatase (increasing) were observed in most patients. In the 3 patients in whom it was performed, repeated bone scanning showed a partial regression of pathological areas in 2 and the complete disappearance of most pathological areas in 1. Our results suggest that 2-dichloromethylene-diphosphonate may represent an important supportive treatment in patients with bone metastases owing to prostatic carcinoma, providing sustained relief of pain and regression of bone destruction without undesirable side effects.

Adult↗
PubMed1984

Simultaneous measurement of 1.25-dihydroxy-vitamin D, 24.25-dihydroxy-vitamin D and 25-hydroxy-vitamin D from a single two milliliters serum specimen. Preliminary clinical application.

A simple method for extraction, purification and separation of the principal vitamin D metabolites from a single serum sample is described. The method involved extraction of serum with acetonitrile followed by a first purification employing C-18 Sep-pak cartridges eluted with methanol/water and acetonitrile. Final separation before assay was carried out by high pressure liquid chromatography. 1.25-dihydroxy-vitamin D was measured with radioimmunoassay using an antiserum (S11) with high selectivity for 1 alpha-OH function of the hormone at a final dilution of 1:100,000. 24.25-dihydroxy-vitamin D and 25-hydroxy-vitamin D were measured employing a competitive binding assay with normal rat serum at a final dilution of 1:10,000 as source of binding protein. The mean (+/- SD) serum 1.25-dihydroxy-vitamin D, 24.25-dihydroxy-vitamin D and 25-hydroxy-vitamin D concentrations for a group of healthy subjects were 50.4 +/- 17.3 pg/ml, 2.3 +/- 2.6 ng/ml and 20.8 +/- 12.3 ng/ml, respectively. 1.25-dihydroxy-vitamin D concentrations were low or undetectable in patients on dialysis or with mild renal failure. High 1.25-dihydroxy-vitamin D levels were found in 2 out of 17 patients with primary hyperparathyroidism. In 4 normal subjects treated for two weeks with large doses of 25-hydroxy-vitamin D, serum 25-hydroxy-vitamin D rose from 12.5 ng/ml to 119 ng/ml and from 0.89 ng/ml to 15 ng/ml, respectively; no changes in the 1.25-dihydroxy-vitamin D assay were found.

24,25-Dihydroxyvitamin D 3↗
PubMed1984

High serum calcitonin levels in heroin addicts.

An involvement of calcitonin in the mechanism of pain perception has recently been hypothesized. In order to collect information about the relationship between this hormone and well known analgesic substances such as opioids, we have studied the serum levels of calcitonin in a group of heroin addicts, finding higher average concentrations than in normal subjects of matched age and sex. In these addicts there were no severe signs of impaired renal or hepatic function, or alterations of the serum levels of calcium and phosphate. So we think that opioids, in a direct or indirect way, can stimulate the secretion of calcitonin.

Adolescent↗
PubMedDate not supplied

Cold-induced rhinitis in skiers--clinical aspects and treatment with ipratropium bromide nasal spray: a randomized controlled trial.

Cold-induced rhinitis (CIR) is common among skiers and is perceived as a troublesome disease. We studied the clinical characteristics of CIR in a population of skiers and we evaluated the effectiveness of ipratropium bromide nasal spray (IBNS) in relieving symptoms in a double-blind placebo-controlled fashion. By means of specific questionnaires, we evaluated 144 subjects (69% men; mean age, 42.2 years). The prevalence of CIR was 48.6% and the distinctive symptom was rhinorrhea (96%), often severe. The prevalence of atopy was higher in the CIR patients (chi2; p = 0.004). Twenty-eight CIR subjects participated in a double-blind placebo-controlled cross-over trial for evaluating the effectiveness of IBNS (80 microg twice per day [b.i.d.]). The severity of symptoms was assessed by a visual analog scale, and the number of cleaning tissues used also was evaluated. The actively treated group showed a significant improvement of rhinorrhea (p = 0.0007) and a reduction in the number of cleaning tissues used (p = 0.0023). Only four mild local side effects were reported. We conclude that IBNS could be regarded as an optimal therapeutic option for treating CIR symptoms in skiers.

Adolescent↗
PubMedDate not supplied

[Isolated ACTH deficiency and transient GH deficiency. Presentation of a case].

In a 46 year old man, who arrived at our observation suffering for three months from considerable increasing weakness and progressive impairment of libido, we documented a condition of secondary hypocorticism due to an isolated ACTH deficiency associated with a reduced somatotropin reserve, the last improved after treatment with corticosteroids. We found low serum levels of ACTH and cortisol, good response of adrenal glands to corticotropin depot, normalization of the clinical board during glucocorticoid replacement. Stimulating test with CRH (corticotropin releasing hormone) did not cause a response in ACTH, suggesting the presence of primitive damage of the hypophyseal corticotroph cells.

Adrenal Insufficiency↗