Search PubMed⌕ Search

Biomedical subjects

R Pacifici

Publications and source records attributed to R Pacifici.

At least 127 records · Page 7Linked to original sources
PubMed1992

Simultaneous determination of cotinine and trans-3'-hydroxycotinine in human serum by high-performance liquid chromatography.

A high-performance liquid chromatographic method with ultraviolet photometric detection has been developed for the quantitation of cotinine and trans-3'-hydroxycotinine in human serum. A solid-phase extraction procedure was performed for the analytes and the internal standard, N-ethylnorcotinine, before chromatography. The use of a 30-cm reversed-phase column and a mobile phase of water-methanol-0.1 M sodium acetate-acetonitrile (67:24.5:6.5:2, v/v), pH 4.3, prevented the co-elution of caffeine with cotinine. The limit of quantitation observed with this method was 5 ng/ml for both cotinine and trans-3'-hydroxycotinine. The present method proved useful for the determination of serum levels of these metabolites, correlating with nicotine daily intake.

Chromatography, High Pressure Liquid↗
PubMed1992

Lateral dual-energy radiography: artifact error from rib and pelvic bone.

A lateral projection of the lumbar spine with dual-energy radiography (DER) may be a more sensitive tool for the detection of vertebral demineralization than the standard anterior-posterior (AP) DER measurement. The lateral view allows measurement of the vertebral body and selective measurement of the central trabecular compartment, excluding the majority of the cortical envelope and posterior vertebral elements. The lateral DER typically contains L2-4 in the region of interest. The present study was designed to investigate the frequency and bone mineral content (BMC) contribution of rib to the L2 vertebral body BMC measurement in a lateral view DER scan. In addition, the frequency of pelvic overlap of L4 was evaluated. All patients were scanned in the supine position. Abdominal CT images of L2 were examined in 20 women aged 28-82 years to determine the frequency of rib and pelvic interference. QCT images of L2 also were examined in an additional 35 women aged 20-82 years to further investigate the frequency of rib overlap and to calculate the potential contribution of rib superimposition to the L2 BMC in a lateral projection. Pelvic overlap of L4 occurred in 15% of the 20 cases reviewed. Rib overlapped the L2 vertebral body in 100% of the L2 images. The expected contribution of rib BMC to L2 BMC in a lateral DER scan was 10.4% on average. There was no relationship between the percentage of rib BMC contribution and age and relatively poor correlations between rib BMC and that of either the vertebral body or the central trabecular compartment of L2. We conclude that supine positioning allows routine inclusion of L3 and L4 in a lateral lumbar scan. Results also suggest that L2 should be excluded from DER scans on patients scanned in either the lateral decubitus or supine position.

Adult↗
PubMed1992

Paget's disease of bone affecting a single vertebra: clinical, radiologic, and histopathologic correlations.

We report a 67-year-old man who presented with a 3-month history of progressively increasing pain in the lumbar spine. His past medical history was unremarkable, and physical examination disclosed local tenderness over the lower spine. No neurologic dysfunction was identified. Routine laboratory evaluation including alkaline phosphatase activity was normal. An X-ray film of the lumbar spine showed enlargement and increased density of L-5 vertebra. A whole-body bone scan revealed markedly increased uptake at the L-5 level. To further evaluate the nature of the disorder and the cause of his pain, a computed tomography (CT) scan was obtained. It disclosed multiple lucent areas with some sclerotic changes mainly affecting the vertebral body of L-5. No spinal stenosis was found. Subsequently, a bone biopsy of L-5 was performed that showed typical findings consistent with Paget's disease. The patient was treated with etidronate (200 mg b.i.d. for 6 months) followed by salmon calcitonin (50 IU 3 times/week s.c. for 6 months). The pain declined gradually in severity and the patient became symptom free after 12 months of treatment. A repeat X-ray film, obtained at that time, showed no significant change. However, a bone scan showed almost complete normalization. The present case illustrates that a high index of suspicion is required when only a single vertebra is affected by Paget's disease, especially, when alkaline phosphatase activity is normal. It may present with severe pain without evidence of neurologic dysfunction. CT scan may be a useful adjunct in establishing the diagnosis and elucidating the cause of pain.

Aged↗
PubMed1992

Effect of estrogen and calcitonin on vertebral bone density and vertebral height in osteoporotic women.

Estrogen and calcitonin increase bone density of osteoporotic women, particularly on the axial skeleton. To verify whether the effect of these drugs might in part be biased by spurious increases in bone density due to radiologically irrelevant microfractures, and consequent subtle decreases in vertebral height, we followed the changes in vertebral bone density (VBD), assessed by quantitative computed tomography, in relation to vertebral height (VH) in 60 osteoporotic women. VH was measured as the sum of anterior, central and posterior heights of L1-L3 vertebral bodies on lateral radiographs. Patients received either salmon calcitonin (sCT: 50 IU subcutaneously three times per week, n = 18), hormonal replacement therapy (HRT: conjugated estrogen 0.625 mg/day, days 1-25, plus medroxyprogesterone acetate 10 mg/day, days 16-25 of each month; n = 21) or calcium alone (Ca: 1000 mg/day, n = 21). After 1 year, VBD increased in the HRT group (+5.0 +/- 1.9%, p = 0.010), did not change significantly in the sCT group (+3.3 +/- 2.3%, p = 0.167), and decreased by 6.1 +/- 1.0% (p less than 0.001) in the Ca group. By analysis of variance, the changes induced by HRT and sCT were significantly different from those observed in the Ca group (F = 7.982, p less than 0.001). VH decreased slightly in all three subsets of patients (-0.9 +/- 0.5% in sCT, -1.5 +/- 0.3% in HRT, -0.1 +/- 0.5% in Ca), but these changes were not significantly different between groups (F = 2.545, p = 0.081).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Immunomodulating properties of carbamazepine in mice.

The protective effects of carbamazepine (CBZ) were studied in mice inoculated with Lewis Lung Carcinoma (3LL), Madison Lung Carcinoma (M109), L5178Y lymphoma, L1210 leukaemia and Candida albicans. There was no significant increase in survival time of mice treated with CBZ. However, CBZ, as well as its metabolite CBZ 10-11 epoxide (CBZ 10-11 EPOX), showed a significant increase in NK-cell activity. CBZ also produced a significant increase of phagocytosis and killing properties of PMNs. There was no significant difference in the stimulation of splenic lymphocyte blastogenesis by different concentrations of phytohaemagglutinina (PHA), observed between the controls and CBZ treated mice. The results demonstrate that the effect of chronic treatment with CBZ on the immune response is a complex phenomenon which remains a challenge for future research.

Adjuvants, Immunologic↗
PubMed1992

How the steady-state cotinine concentration in cigarette smokers is directly related to nicotine intake.

The relationship between nicotine intake and steady-state cotinine concentration was studied in a sample of 125 subjects who smoked their usual brands of cigarettes. Nicotine and tar yield of cigarettes was determined with a smoking machine, under standardized conditions. Blood was drawn about 8 hours after the last cigarette was smoked and serum cotinine was measured by high performance liquid chromatography. Cotinine levels ranged from 11 to 400 ng/ml, and nicotine daily intake ranged from 1 to 33 mg/day. Regression analysis and the correlation coefficient, r = 0.919, significant at p less than 0.0001, showed that steady-state cotinine level was linearly and directly related to daily available nicotine, with an increase in correlation coefficient directly related to the increase in tar and nicotine yield. From the findings we also conclude that smokers of low-tar cigarettes do not tend to compensate for lower yields of nicotine.

Adolescent↗
PubMed1992

Collagen-induced release of interleukin 1 from human blood mononuclear cells. Potentiation by fibronectin binding to the alpha 5 beta 1 integrin.

PBMC express cell surface receptors for extracellular matrix components known as integrins. We have recently shown that ligand binding to one PBMC integrin, the collagen receptor alpha 2 beta 1, stimulates the secretion of interleukin 1 (IL-1). We have now investigated the role of fibronectin (Fn), an adherence protein that has binding sites for both PBMC and collagen, in the generation of the IL-1 response to collagen. In contrast to collagen, Fn did not stimulate IL-1 release but Fn-depleted serum decreased the release of IL-1 induced by collagen. A polyclonal antiserum directed against Fn also decreased the collagen-induced IL-1 secretion. The IL-1 response to collagen from cells incubated in Fn-depleted serum was restored by the addition of either purified Fn or the 120-kD cell-binding fragment of Fn, which contains the cell-binding site but not the collagen-binding domain. Smaller Arg-Gly-Asp (RGD) peptides failed to enhance the PBMC response to collagen but inhibited in a concentration-dependent fashion the potentiating effect Fn. As expected, a MAb against the alpha 2 beta 1 collagen receptor decreased collagen-induced IL-1 release. However collagen-induced IL-1 release was also inhibited by a MAb against the alpha 5 beta 1 Fn receptor. The effect of the two MAbs was not additive, suggesting that the occupancy of both receptors by ligands is required in order for collagen to induce an maximal response from PBMC. The mechanism by which Fn exerts its effect remains unknown. However, flow-cytometric analysis revealed that Fn does not alter expression of the alpha2beta1 receptor on PBMC. These data demonstrate a potentiating effect of Fn on the collagen-induced secretion of IL-1 from human PBMC and suggest that this effect is mediated via the integrin alpha5beta1. These findings indicate a complex interactive role for specific integrin receptors in the regulation of the mononuclear cell immune response.

Amino Acid Sequence↗
PubMed1992

Immunological consequences of zidovudine treatment in control and morphine or methadone treated mice.

The effects of acute and chronic zidovudine (AZT) administration on immunologic test responses of mice were studied. The effects of AZT administration combined with morphine or methadone treatment, were also studied separately comparing the effects of each drug. We noted that AZT-treatment did not modify the T-lymphocyte subsets (L3T4/LyT2 rate), whereas morphine-treatment and AZT plus morphine treatment decreased the percentage of T helper cells. Acute and chronic AZT-treatment increased Natural Killer cell (NK) activity and also recovered the decreased NK cell activity produced by morphine-treatment. AZT-treatment, morphine-treatment, AZT plus morphine treatment and AZT plus methadone treatment strongly depressed the phagocytic physiological activity of Polymorphonuclear leukocytes (PMNs). Another evidence of immunologic responsiveness against AZT was the reduction of the mitogenic and antigenic response of lymphocytes. These results suggest a negative role of AZT-treatment especially on phagocytic activity and confirms a depressive effect of morphine-treatment on several immune functions studied. Furthermore, there is no indication of additive or synergistic toxic effects of AZT, morphine and methadone on the immune functions above that seen with each of these drugs when tested alone.

Animals↗
PubMed1991

Elimination of caffeine interference in high-performance liquid chromatographic determination of cotinine in human plasma.

A high-performance liquid chromatographic method with ultraviolet photometric detection for the determination of cotinine in human plasma was described. The use of a 30-cm reversed-phase column and of a mobile phase consisting of water-methanol-0.1 M sodium acetate-acetonitrile (72:21:5.6:1.4, v/v), pH 4.1, eliminated caffeine interference. A simplified solid-phase extraction procedure was also performed for plasma samples.

Caffeine↗
PubMed1991

Determination of naltrexone and 6 beta-naltrexol in plasma by high-performance liquid chromatography with coulometric detection.

A simple and reliable reversed-phase high-performance liquid chromatographic method with coulometric detection is described for the quantitation of naltrexone and its metabolite, 6 beta-naltrexol, in plasma samples of healthy volunteers who received orally 50 mg of naltrexone. The analytes and the internal standard, naloxone, are extracted with an octadecyl solid-phase extraction column before chromatography. The mobile phase is 0.01 M potassium phosphate (pH 3)-acetonitrile (85:15, v/v) and it is pumped at 0.8 ml/min. The coulometric detector is formed by two electrodes set at +0.20 V and +0.70 V, with a palladium reference electrode. The limit of quantitation observed was 5 ng/ml for both naltrexone and 6 beta-naltrexol. This method can be used to investigate pharmacokinetic parameters of different pharmaceutical preparations of this opioid antagonist.

Chromatography, High Pressure Liquid↗
PubMed1991

Effect of surgical menopause and estrogen replacement on cytokine release from human blood mononuclear cells.

To determine whether mononuclear cell secretory products contribute to the changes in bone turnover that characterize the development of postmenopausal osteoporosis, we evaluated the effects of oophorectomy and subsequent estrogen replacement on the spontaneous secretion of interleukin 1 (IL-1) and tumor necrosis factor alpha (TNF-alpha) and on the phytohemagglutinin A-induced secretion of granulocyte-macrophage colony-stimulating factor (GM-CSF) from peripheral blood mononuclear cells. In 15 healthy premenopausal women who underwent oophorectomy, increases in GM-CSF activity were observed as early as 1 week after surgery, whereas elevations in IL-1 and TNF-alpha and in hydroxyproline/creatinine and calcium/creatinine ratios, two urinary indices of bone resorption, were detectable 2 weeks after the surgical procedure. Six of the oophorectomized women received no estrogen therapy after surgery and in these subjects hydroxyproline/creatinine and calcium/creatinine ratios plateaued 6 weeks postoperatively, and all three cytokines reached the highest levels 8 weeks after oophorectomy, when the study ended. In the remaining 9 women, who were started on estrogen replacement therapy 4 weeks after oophorectomy, decreases in the indices of bone resorption paralleled decreases in the secretion of the cytokines, with lower levels detected after 2 weeks of therapy. In the women who did not receive estrogen therapy, circulating osteocalcin, a marker of bone formation, increased beyond preoperative levels 8 weeks after oophorectomy, whereas in the estrogen-treated subjects osteocalcin remained unchanged in the entire study period. In 9 female controls who underwent simple hysterectomy, cytokine release and biochemical indices of bone turnover did not change after surgery. These data indicate that changes in estrogen status in vivo are associated with the secretion of mononuclear cell immune factors in vitro and suggest that alterations in the local production of bone-acting cytokines may underlie changes in bone turnover caused by surgically induced menopause and estrogen replacement.

Adult↗
PubMed1991

Epileptic patients refractory to drug therapy.

We compared two groups of patients with idiopathic epilepsy, 41 patients whose seizure frequency was not controlled by adequate therapy and 39 patients in good seizure control, in respect of hematology, kidney and liver function tests, serum IgG, IgA and IgM concentrations and drug concentrations. The only difference that emerged were in the serum immunoglobulins, which were raised in the drug refractory group, significantly (p less than 0.01) so in the case of IgG. Failure of seizure control did not depend on inadequacy of drug dose or of blood concentration. Although the serum Ig changes do not warrant the assumption of an immunological origin for drug resistance, they do suggest a useful research line.

Adult↗
PubMed1991

A highly sensitive chemiluminescent assay for glycerylphosphorylcholine in human seminal plasma.

Glycerylphosphorylcholine (GPC), one of the major phosphorus-containing-choline compounds of seminal plasma, is secreted mainly by the epididymal epithelium under androgenic control. This study reports a new method that uses chemiluminescence to determine seminal GPC content, comparing it with a spectrophotometric technique. The results, obtained with both techniques studying 20 fertile patients (as control), 35 infertile patients with normospermia, 23 infertile patients with oligozoospermia and impaired motility and 9 patients with excretory azoospermia, demonstrate that the GPC chemiluminescent assay is more sensitive, simple and rapid than the spectrophotometric assay. Our data confirm that GPC may be used as a marker of vas deferens and ejaculatory duct perviousness, suggesting a possible role of this glycerophosphodiester in sperm motility.

Glycerylphosphorylcholine↗
PubMed1991

Fat body mass and pharmacokinetics of oral 6-mercaptopurine in children with acute lymphoblastic leukemia.

To evaluate the reasons for the wide variability in bioavailability of orally administered 6-mercaptopurine in children with acute lymphoblastic leukemia, we studied several pharmacokinetic parameters of the drug in 18 affected children receiving remission maintenance therapy, and compared them with their anthropometric data and with the results of intestinal function tests. No correlation was found between estimates of small intestinal absorption (the oral lactose tolerance test and 1 h blood xylose test) and 6-mercaptopurine serum levels. Of the anthropometric measurements considered, only the weight/height percentile (an index of the fat body mass) strongly and linearly correlated with the area under the curve of 6-mercaptopurine. The dose of 75 mg of 6-mercaptopurine/m2 of body surface resulted in higher serum concentrations in children below the 75th percentile than in those with a weight/height ratio exceeding the 75th percentile. In conclusion, these data caution about the risk of underdosing 6-mercaptopurine in overweight children when administering it on the basis of body surface area.

Administration, Oral↗
PubMed1991

Bone matrix constituents stimulate interleukin-1 release from human blood mononuclear cells.

To test the hypothesis that mononuclear cells are stimulated to release interleukin 1 (IL-1) by bone fragments released in the bone microenvironment during the remodeling cycle, we have investigated the effects of bone matrix and some of its constituents on IL-1 secretin from peripheral blood mononuclear cells (PBMC). Increases in IL-1 activity were observed when either PBMC or adherent monocytes, but not lymphocytes depleted of monocytes, were co-cultured with either human or rat bone particles but not with latex particles of similar size. Co-culture of PBMC with bone particles in a transwell system where the cells were physically separated from the bone particles, or with osteoblast- or osteoclast-covered bone particles, did not stimulate IL-1 release, indicating that a physical contact between PBMC and the bone surface is required for eliciting IL-1 release. This was confirmed by the finding of a lower stimulatory effect of bone particles pretreated with etidronate, a bisphosphonate which decreases the bone binding capacity of PBMC. Constituents of bone matrix, such as collagen fragments, hydroxyproline, and, to a lesser extent, transforming growth factor-beta, but not osteocalcin, alpha 2HS glycoprotein, fragments of either bone sialoprotein or osteopontin, and fibronectin, stimulated PBMC IL-1 release in a dose-dependent fashion. Collagen-stimulated IL-1 release was partially and specifically inhibited by a monoclonal antibody directed against the alpha 2 beta 1-integrin cell surface collagen receptor. These data demonstrate that products of bone resorption, known to be chemotactic for mononuclear cells, stimulate PBMC IL-1 activity. These findings may help explain previous documentation of increased IL-1 secretion by circulating monocytes obtained from patients with high turnover osteoporosis.

Animals↗
PubMed1991

Systemic mastocytosis presenting as osteoporosis: a clinical and histomorphometric study.

Ten patients with systemic mastocytosis (SM) were evaluated for their metabolic bone disease (4 men and 6 women; mean +/- SD, 59 +/- 13 yr). All patients presented with generalized osteopenia and/or atraumatic vertebral compression fractures. Three patients had long-standing urticaria pigmentosa; in these, the diagnosis of cutaneous mastocytosis had been established by skin biopsy. One of the 3 and 2 of the other 7 individuals had symptoms suggestive of SM. Although six patients had previously undergone decalcified bone marrow trephine core biopsy (DBMB), findings were consistent with SM in only 2 of them. X-Ray survey revealed generalized osteopenia in all 10 patients and vertebral compression fractures in 9. No patient had sclerotic bone lesions. Histological findings of undecalcified transiliac crest biopsy (UTBB) specimens from 9 patients (5 patients underwent both DBMB and UTBB, 4 underwent only UTBB, and 1 had only DBMB) disclosed bone marrow that contained nodules characteristic of mast cell granulomas and numerous scattered oval- and spindle-shaped mast cells. The trabecular bone contained abundant newly synthesized bone matrix and a significant increase in osteoblastic, osteoclastic, and resorptive surfaces. Dynamic histomorphometric parameters revealed a significantly increased mineral apposition rate. Our study suggests that SM may be a more frequent cause of osteoporosis than previously recognized. Generalized osteopenia with compression fractures may be the only presentation of SM. Undecalcified bone biopsy is useful in the diagnosis of SM. Accelerated bone remodeling is a characteristic histomorphometric feature of SM with diffuse osteopenia.

Adult↗
PubMed1991

A comparison of dual energy radiography measurements at the lumbar spine and proximal femur for the diagnosis of osteoporosis.

In this study we assessed the ability of proximal femur and spine DER measurements to discriminate between control (C) and osteoporotic (OP) subjects as well as the reproducibility of the femoral DER technique. DER measurements of the proximal femur and spine (L2-L4) were obtained in 58 control (unfractured) and 54 osteoporotic (vertebral fractured) women. Linear regression analyses for each site with age suggested that density values from the Ward's triangle region explained the majority of variance due to age in the decline of bone density in both control (r = -0.45; P less than 0.0005) and osteoporotic subjects (r = 0.34; P less than 0.05), with similar findings for the femoral neck in OP subjects (r = -0.30; P less than 0.05). No other femoral site produced a significant correlation with age, and vertebral measurements were the lowest in OP subjects (r = -0.11; P = NS). Cross-sectional rates of bone loss in each region implied that for OP subjects the Ward's triangle and femoral neck regions detected the largest amount of bone loss (0.64% and 0.38%/yr, respectively), while vertebral measurements were again the smallest (0.19%/yr). Results indicated that proximal femur measurements can be obtained with relatively good precision (coefficients of variation ranged from 1.9% for femoral neck to 3.0% for Ward's triangle). Finally, receiver operating characteristic curves revealed that both Ward's triangle and femoral neck densities were able to more successfully discriminate control from osteoporotic subjects than vertebral measurements. These data support the contention that measurement of skeletal sites rich in trabecular bone, such as the femur, are more useful for diagnosing osteoporosis than DER measurements of the lumbar spine. The data also suggest that the femur may be a better site than the lumbar spine for the clinical evaluation of osteoporosis with the DER technique.

Aged↗