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Biomedical subjects

C Ripamonti

Publications and source records attributed to C Ripamonti.

At least 37 records · Page 2Linked to original sources
PubMed2000

Discriminant capacity of quantitative ultrasound versus dual X-ray absorptiometry to determine cancellous bone loss in ovariectomized rats.

The capacity of dual x-ray absorptiometry and quantitative ultrasound to discriminate bone loss and to predict the mechanical and microarchitectural properties of cancellous bone in an animal model of osteopenia was evaluated. Thirty-five female Sprague-Dawley rats (10 months old) were randomized into three groups: baseline group, 10 rats killed at the beginning of the study; ovx group, 15 rats ovariectomized; and sham group, 10 rats sham operated. At the beginning and end of the study, all the animals underwent osteosonography to record the proximal tail (C3 vertebra) bone speed of sound. Sixteen weeks after surgery, the animals were euthanized and the L5-6 lumbar vertebrae of each rat were excised for densitometric, biomechanical (compression test), and histomorphometric studies. Significant differences were found among the groups for final speed of sound (p = 0.01). The L5 bone mineral density of the ovx group decreased by 12.1% (p = 0.049) and 12.6% (p = 0.035) compared, respectively, with baseline and sham groups. The biomechanical parameters of the ovx group decreased by 15-47% compared with the other groups, showing significant differences between the ovx and sham groups both for maximal stress (p = 0.026) and elastic modulus (p = 0.013). Histomorphometric parameters of the ovx group showed significant decreases in comparison with other groups. Logistic regression analysis showed that dual X-ray absorptiometry and quantitative ultrasound discriminate ovariectomized and healthy rats with a similar capacity, classifying correctly all rats used in the model in a range of 61-70%. This similar capacity seems to derive from two different capacities to detect bone changes. Dual X-ray absorptiometry, depending on bone mineralization and density, is able to detect modifications in bone stiffness and strength, confirmed also by the correlation with biomechanical data. On the contrary, quantitative ultrasound seems to depend more on cancellous bone microarchitecural changes because it is correlated to histomorphometric parameters.

Absorptiometry, Photon↗
PubMed2000

Invariant cone-excitation ratios may predict transparency.

Cone-excitation ratios for pairs of surfaces are almost invariant under changes in illumination and offer a possible basis for color constancy [Proc. R. Soc. London Ser. B 257, 115 (1994)]. We extend this idea to the perception of transparency on the basis of the close analogy between the changes in color signals that occur for surfaces when the illumination changes and the changes in color signals when the surfaces are covered by a filter. This study presents measurements and simulations to investigate the conditions under which cone-excitation ratios are statistically invariant for physically transparent systems. The invariance breaks down when the spectral transmission of the filters is low at some or all wavelengths. We suggest that cone-excitation ratios might be useful to define the stimulus conditions necessary for the perception of transparency.

Color↗
PubMed1999

Suicide among patients with cancer cared for at home by palliative-care teams.

Patients with terminal cancer are thought to be at high risk of committing suicide. In a population of 17,964 patients with terminal cancer cared for at home by 12 palliative-care teams, five patients committed suicide. We speculate that continuing care made up by symptomatic treatment and psychosocial support given to these patients may reduce the risk.

Aged↗
PubMed1999

The mechanical properties of fluoride-treated bone in the ovariectomized rat.

The effect of fluoride therapy on the osteopenic bone of the ovariectomized rat was studied by comparing the densitometric and biomechanical data. Forty retired breeder female Sprague-Dawley rats aged 10 months were randomly divided into five groups. One group (Group A) was killed at the beginning of the study and was used as a baseline. Three groups were ovariectomized and one was sham-operated (Group B) and observed for the same period as a sham-aged group. A group of ovariectomized rats was used as a sham therapy control (Group C) and received only deionized drinking water; the other two groups (F1 and F2) received L-glutamine monofluorophosphate and calcium at a rate of 1:30 F/Ca at different doses by gavage (0.57 mg F/17 mg Ca per kg/day-Group F1; 0.21 mg F/6.30 mg Ca per kg/day-Group F2). Densitometric and biomechanical (compression and three-point bending test) assays, X-ray diffraction, and Fourier transformed infrared spectroscopy were performed on femoral specimens. Biomechanical data showed that the femoral heads of Group F2 required a significantly greater energy-to-failure than Group C (P < 0.05) as well as treated femoral diaphysis when compared with the others (P < 0.01). Significant increases in the elastic modules were observed in fluoride-treated groups (P < 0.001) when compared with other groups. Diffractometric and spectroscopic data showed the presence of fluorine-apatite in both treated groups with a high component of carbonates. Also, fluoride therapy causes an increase of bone stiffness due to the presence of fluoroapatite. It seems to produce two opposed properties in the osteopenic rat bone: a higher resistance to compression loading and a greater frailty to flexion loading.

Animals↗
PubMed1999

Management of dyspnea in advanced cancer patients.

Dyspnea is a frequent and devastating symptom among advanced cancer patients and is often difficult to control. However, there has been considerably less emphasis in the literature on the appropriate characterization and management of this symptom than of other cancer-related symptoms. The purpose of this paper is to review issues relating to the prevalence, causes, prognosis and treatment of dyspnea in patients with advanced cancer. A Medline search of the literature published from 1966 to February 1999 was conducted. Dyspnea occurs in 21-78.6% of advanced cancer patients and is reported to be from moderate to severe in 10-63% of the patients. The frequency and severity of dyspnea increase with the progression of the disease and/ or when death is approaching. Lung cancer patients with dyspnea have shorter survival than patients with other types of cancer. Dyspnea can be a direct effect of the cancer, an effect of therapy or not related to the cancer or therapy. In addition to cancer, patients may suffer from chronic obstructive pulmonary disease, congestive heart failure, nonmalignant pleural effusion, pneumonitis, air flow obstruction, or bronchospasm associated with asthma. In the absence of lung or heart disease, dyspnea may be a clinical expression of the syndrome of overwhelming cachexia and asthenia or of severe asthenia. Many different causes may co-exist in a patient. Whenever possible, an attempt should be made to treat underlying cancer. Radiotherapy and chemotherapy may relieve dyspnea also in patients who fail to achieve a major objective response. Symptomatic measures in addition to specific treatments for the underlying cancer and/or other pulmonary and cardiovascular diseases are indicated. Oxygen therapy has proved effective in hypoxemic and nonhypoxemic patients. The role of transfusion therapy to relieve anemia-related dyspnea in advanced and terminal cancer patients is still controversial. Oral, subcutaneous and intravenous opioids are effective but underused in these patients, whereas currently available evidence does not support the clinical use of nebulized opioids. While benzodiazepines are frequently used in patients with dyspnea, these drugs were ineffective in four out of five randomized controlled trials. Other components of the symptom expression are better managed by supportive counseling, occupational therapy or physiotherapy. While the mechanism of breathing and the consequences of different pathologic conditions for both respiratory function and gas exchange are well known, the genesis and pathophysiology of dyspnea as a symptom are much less well understood. Palliative care assessment should be focused on dyspnea as a symptom rather than on the functional and gas exchange abnormalities. Increased research on the appropriate management of dyspnea is needed.

Dyspnea↗
PubMed1999

Geometry of proximal femur in the prediction of hip fracture in osteoporotic women.

111 White post-menopausal women with hip fracture and 329 healthy controls were studied in order to determine whether proximal femur geometry predicts hip fracture and improves the discriminant ability of femoral neck bone mineral density (BMD) in elderly women. All subjects underwent dual X-ray photon absorptiometry (DXA) of the hip from which the femoral neck BMD, hip axis length, femoral neck width and femoral neck-shaft angle were measured. Fractured subjects had a lower femoral neck BMD, a longer hip axis length and a more valgus neck-shaft angle. The hip axis length correlated significantly with neck-shaft angle, femoral neck width and age. No significant correlation was found between neck-shaft angle and age. On standardized logistic regression, the hip axis length and the neck-shaft angle predicted fracture independently of BMD after correction for age, weight and femoral neck BMD. The femoral neck BMD significantly discriminated fractured subjects after correction for all potential confounders. The logistic models containing simultaneously one femoral geometric parameter and the neck BMD discriminated significantly better than those containing the same variables as single predictor. Our data suggest that hip axis length may play a role in fracture risk and supports a similar role for neck-shaft angle. Combining proximal femur geometric measurements and femoral neck BMD improved the discriminant ability of each measurement.

Absorptiometry, Photon↗
PubMed1999

Calcitriol and alendronate combination treatment in menopausal women with low bone mass.

Serum calcitriol levels decrease with advancing age in relation to reduced dietary intake or poor intestinal absorption of vitamin D. These decreased levels affect the development of senile osteopenia, which can be effectively prevented by the administration of alendronate and calcium. To evaluate the effect of a combined treatment with alendronate and calcitriol on bone mineral density (BMD), we followed 152 osteopenic postmenopausal women, aged 55-75 years, for 9 months. They were divided into three groups. The first group was treated every other day with 0.25 microgram of synthetic 1,25-dihydroxyvitamin D3 plus 10 mg alendronate. The second group received the same dose of alendronate plus calcium (500 mg/day). The third group received only calcium (500 mg/day). BMD measurements were made at the level of the lumbar spine and the femoral neck. At the beginning and at the end of the period of treatment the same biochemical analyses of bone metabolism were made. There were no significant differences in the baseline values of the three groups in the biological parameters. Alendronate plus calcium treatment led to a significant reduction in total alkaline phosphatase and hydroxy prolinuria as well as to a significant increase in lumbar and femoral bone density. The same changes were observed in the group treated with alendronate plus calcitriol except that femoral BMD did not significantly improve. These results show that continuous treatment for 9 months with calcitriol or calcium in combination with alendronate significantly increases both vertebral and femoral neck density (from 3.8% to 4.5% and from 0.61% to 2.36% respectively) in osteopenic postmenopausal women. The effects of both combinations on bone mass are clearly greater than those achieved by calcium monotherapy.

Aged↗
PubMed1998

A randomized, controlled clinical trial to evaluate the effects of zinc sulfate on cancer patients with taste alterations caused by head and neck irradiation.

BACKGROUND: In uncontrolled clinical trials, the administration of oral zinc sulfate has been reported both to prevent and correct taste abnormalities in cancer patients receiving external radiotherapy (ERT) to the head and neck region. METHODS: Eighteen patients were randomized to receive either zinc sulfate tablets (a dose of 45 mg) or placebo tablets three times a day at the onset of subjective perception of taste alterations during the course of ERT and up to 1 month after ERT termination. Taste acuity was determined by measuring detection and recognition thresholds for four taste qualities. Intolerance of zinc sulfate or placebo administration was investigated, and the oral cavity was examined. All the evaluations were studied prior to, at weekly intervals during, and 1 month after ERT administration. RESULTS: Taste acuity for one or more taste qualities was already impaired before ERT. During ERT treatment, taste alterations were experienced at least once for a minimum of 3 of the 8 measured thresholds by 100% of the patients, and 33.3% of the patients became aware of some alteration within the first week of treatment. The patients treated with placebo experienced a greater worsening of taste acuity during ERT treatment compared with those treated with zinc sulfate. One month after ERT was terminated, the patients receiving zinc sulfate had a quicker recovery of taste acuity than those receiving placebo. Statistically significant differences between the two groups emerged for urea detection and sodium chloride recognition thresholds during ERT treatment and for sodium chloride, saccharose, and hydrogen chloride recognition thresholds after the termination of ERT treatment. CONCLUSIONS: This pharmacologic therapy is effective and well tolerated; it could become a routine in clinical practice to improve the supportive care of patients with taste alterations resulting from head and neck cancer.

Administration, Oral↗
PubMed1998

The role of bisphosphonates in the treatment of painful metastatic bone disease: a review of phase III trials.

Metastatic bone disease is a frequent cause of morbidity in advanced cancer patients with a subsequent high incidence of skeletal complications (fractures, hypercalcemia, spinal cord compression) and severe pain. The osteolytic process is mainly characterized by an osteoclastic activity of bone resorption and inflammatory activity provoked by various cytokines and prostaglandins. Bisphosphonates represent a new class of drugs with inhibitory activity on bone resorption and on inflammatory processes which revealed themselves to be efficacious in a series of clinical conditions such as tumour-induced hypercalcemia, Paget's disease, osteoporosis and metastatic bone disease. The aim of this review of the literature is to show the analgesic efficacy of the different bisphosphonates in phase III studies carried out on patients with metastatic bone disease. Medline and Cancerlit database from January 1984 to February 1998 have been considered. From the analysis of the published studies it appears that bisphosphonates and, in particular, intravenous Disodium Pamidronate, are not only able to slow down the progression of the disease and to reduce the onset of skeletal complications but also have an analgesic effect and the possibility of improving the quality of life, above all in patients with osteolytic metastases due to breast cancer and multiple myeloma. Bisphosphonates represent a further valid therapy to add to an already consolidated list of therapies such as radio, chemo and endocrine therapy, analgesic drugs, orthopaedic and physiatric in the pain management of patients with bone metastases. These drugs meet with the patients' compliance, are well-tolerated as well as having a good cost/efficacy profile. It still remains to be seen if the newer and more potent bisphosphonates such as Ibandronate and Zoledronate can be administered differently from the intravenous route such as by mouth or by patch which are readily accepted by the patient and, moreover, if these more potent drugs are able to prevent or delay the onset and/or the progression of bone metastases.

Bone Neoplasms↗
PubMed1998

Carcinoid somatostatinoma of the duodenum.

Carcinoid somatostatinoma is a rare neuroendocrine malignant tumour and the duodenal location is an atypical site of presentation of which only few cases have been reported in the literature. A case of duodenal carcinoid somatostatinoma metastatic to lymph nodes in a 66-year-old patient is presented with an update of the literature. No relevant signs or symptoms were associated to the retrogastric lymph-node mass, which deformed but did not infiltrate the stomach wall. At the first and third portion of the duodenum, two polipoid endoluminal nodules (size 1 cm) were found with adjacent adenopathy partially adherent to the head of the pancreas and with thickening of the antropyloric wall. The patient underwent antrectomy duodenum mobilization and lymphadenectomy in the hepatic artery region. The treatment was successful and, over 3 years after diagnosis, there has been no clinical or radiological evidence of relapse. Duodenal somatostatinoma is rare and its diagnosis is often incidental. Surgery would be the appropriate treatment in the early stage of the disease with good chances of cure.

Aged↗
PubMed1998

Equianalgesic dose/ratio between methadone and other opioid agonists in cancer pain: comparison of two clinical experiences.

BACKGROUND: Oral methadone is considered to be a valid opioid analgesic alternative to morphine and hydromorphone in treating cancer pain. However, the use of methadone could be complicated by the limited knowledge of the equianalgesic dose/ratio with the other analgesic opioids when switching in tolerant patients. PATIENTS AND METHODS: In two Palliative Care Units, data collected regarding 88 advanced cancer patients with pain switched from different opioids to oral methadone were reviewed and compared with the aim of determining the equianalgesic dose ratio in relation to the dose of opioid previously administered. RESULTS: The results of this retrospective study suggest that: (1) methadone is much more potent than previously described in literature, (2) the dose ratio between hydromorphone and methadone is higher than as suggested by equianalgesic tables, and (3) the ratio correlates with total opioid dose administered before switching. CONCLUSIONS: The fact that methadone ratio is different according to the opioid dose used previously should be taken into careful consideration by the clinician in order to avoid severe toxicity or death during switchover. Prospective studies should be carried out in order to better define our findings.

Administration, Oral↗
PubMed1998

Side effects of morphine administration in cancer patients.

According to the World Health Organization (WHO) guidelines, oral morphine is the first choice drug for treating moderate to severe cancer-related pain. The fear of the side effects caused by this drug and the scarce information about prevention and management of these effects are the main reasons for the underuse of morphine. The aim of this paper is to provide a review of the literature on the side effects most frequently present both in the titration phase and during chronic administration of oral morphine and to describe the appropriate treatment.

Administration, Oral↗
PubMed1998

Switching from morphine to oral methadone in treating cancer pain: what is the equianalgesic dose ratio?

PURPOSE: To define the dose ratio between morphine and methadone in relation to the previous morphine dose and the number of days needed to achieve the same level of analgesia in a group of patients with advanced cancer with pain who switched from morphine to oral methadone. PATIENTS AND METHODS: A cross-sectional prospective study of 38 consecutive cancer patients who switched from morphine to oral methadone was performed. The intensity of pain before, during, and after the switching period was assessed through a four-point verbal Likert scale. The relationship between previous morphine dose and the final equianalgesic methadone dose, dose ratio between morphine and methadone, and the number of days required to achieve equianalgesia have been examined by means of Pearson's correlation coefficient, scatter plots, and Cuzick's test for trend respectively. RESULTS: Before the switch, the median oral equivalent daily dose of morphine was 145 mg/d; after the switch, the median equianalgesic oral methadone dose was 21 mg/d. A median time of 3 days (range, 1 to 7 days) was necessary to achieve the equianalgesia with oral methadone; the lower the preswitching morphine dose, the fewer days necessary to achieve equianalgesia with oral methadone (P < .001). Dose ratios ranged from 2.5:1 to 14.3:1 (median, 7.75:1), which indicated that, in most cases, the dose ratio was much higher than that suggested by the published equianalgesic tables. A strong linear positive relationship between morphine and methadone equianalgesic doses was obtained (Pearson's correlation coefficient, 0.91). The dose ratio increased with the increase of the previous morphine dose with a much higher increase at low morphine doses. CONCLUSION: The results of our study confirm that methadone is a potent opioid, more potent than believed. Caution is recommended when switching from any opioid to methadone, especially in patients who are tolerant to high doses of opioids.

Administration, Oral↗