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Biomedical subjects

G Maggi

Publications and source records attributed to G Maggi.

At least 19 recordsLinked to original sources
PubMed1999

Inducing placebo respiratory depressant responses in humans via opioid receptors.

Several lines of evidence indicate that placebos produce analgesia through the activation of endogenous opioid systems. Recently, we showed that placebos may also produce respiratory depressant responses, a typical side-effect of narcotics, when a subject had a prior experience of respiratory depression in the course of narcotic treatment. In the present study, we report that the placebo respiratory depression can be induced after repeated administrations of the partial opioid agonist buprenorphine. The placebo respiratory depressant effect that resulted from the buprenorphine conditioning was completely blocked by a dose of 10 mg of naloxone, indicating that it was mediated by endogenous opioids. These findings show that placebos act, via the activation of opioid receptors, not only on pain mechanisms but on the respiratory centres as well, thus mimicking a typical side-effect of narcotics. In addition, the experimental procedure we used did not produce any expectation of respiratory depression and, similarly, the subjects did not notice any sign of respiratory discomfort. Thus, the placebo respiratory depression elicited in the present study cannot be explained on the basis of cognitive or motivational mechanisms. Rather, it appears to be a sequence effect due to learning, thus suggesting a conditioning mechanism mediated by endogenous opioids.

Aged↗
PubMed1998

Neurophysiologic assessment of nerve impairment in posterolateral and muscle-sparing thoracotomy.

OBJECTIVE: This study was aimed at analyzing the degree of intercostal nerve impairment in posterolateral and muscle-sparing thoracotomy and at correlating the nerve damage to the severity of long-lasting postthoracotomy pain. METHODS: Neurophysiologic recordings were performed 1 month after either posterolateral or muscle-sparing thoracotomy to assess the presence of the superficial abdominal reflexes (mediated in part by the intercostal nerves), the somatosensory-evoked responses after electrical stimulation of the surgical scar, and the electrical thresholds for tactile and pain sensations of the surgical incision. RESULTS: The patients who underwent a posterolateral thoracotomy showed a higher degree of intercostal nerve impairment than the muscle-sparing thoracotomy patients as revealed by the disappearance of the abdominal reflexes, a larger reduction in amplitude of the somatosensory-evoked potentials, and a larger increase of the sensory thresholds to electrical stimulation for both tactile perception and pain. In addition, these neurophysiologic parameters were highly correlated to the postthoracotomy pain experienced by the patients 1 month after surgery, indicating a causal role for nerve impairment in the long-lasting postoperative pain. CONCLUSIONS: This study shows for the first time the pathophysiologic differences between posterolateral and muscle-sparing thoracotomy and suggests that the minor long-lasting postthoracotomy pain in muscle-sparing thoracotomy patients is partly due to a minor nerve damage. In addition, because nerve impairment is responsible for the long-lasting neuropathic component of postoperative pain, it is necessary to match specific treatments to the neuropathic pain-generating mechanisms.

Case-Control Studies↗
PubMed1998

Dose-response relationship of opioids in nociceptive and neuropathic postoperative pain.

The treatment of neuropathic pain with opioid analgesics is a matter of controversy among clinicians and clinician scientists. Although neuropathic pain is usually believed to be only slightly responsive to opioids, several studies show that satisfactory analgesia can be obtained if adequate doses are administered. In the present study, we tested the effectiveness of buprenorphine in 21 patients soon after thoracic surgery (nociceptive postoperative pain) and 1 month after surgery in the same 21 patients who developed postthoracotomy neuropathic pain with a burning, electrical and shooting quality. According to a double-blind randomized study, the analgesic dose (AD) of buprenorphine needed to reduce the long-term neuropathic pain by 50% (AD50) was calculated and compared to the AD50 in the immediate postoperative period. We found that long-term neuropathic pain could be adequately reduced by buprenorphine. However, the AD50 in neuropathic pain was significantly higher relative to the AD50 in the short-term postoperative pain, indicating a lower responsiveness of neuropathic pain to opioids. We also found a strict relationship between the short-term and long-term AD50, characterized by a saturating effect. In fact, if the AD50 soon after surgery was low, the AD50 increase in the long-term neuropathic pain was threefold. By contrast, if the AD50 soon after surgery was high, the AD50 in neuropathic pain was only slightly increased. This suggests that, though neuropathic pain is indeed less sensitive to opioids, in some neuropathic patients a large amount of opioid resistance is already present in other painful conditions.

Aged↗
PubMed1998

The specific effects of prior opioid exposure on placebo analgesia and placebo respiratory depression.

Although in most of the cases the placebo response appears to be unpredictable, several factors have been considered in order to explain the placebo analgesic effect. For example, it is widely recognized, albeit with little empirical evidence, that placebo analgesia is more likely to occur after a successful analgesic therapy. On the basis of this assumption, we tested the placebo response in a population of patients who were treated with buprenorphine the day before for relieving postoperative pain. However, due to the high variability of opioid responsiveness, buprenorphine was effective in some patients and poorly effective in some others. Similarly, buprenorphine produced respiratory depression with a large variability, ranging from mild depression to no effect. We found that the placebo analgesic response depended on the buprenorphine analgesic effectiveness of the previous day. Analogously, we found that a placebo respiratory depressant response was more pronounced in those patients with a respiratory depressant response to buprenorphine on the day before, irrespective of the analgesic effectiveness. These specific effects suggest that (1) the placebo effect is experience-dependent; (2) the mechanisms underlying placebo analgesia and placebo respiratory depression are independent from each other and, by considering the role of endogenous opioids in placebo analgesia, might involve different subpopulations of opioid receptors.

Analgesia↗
PubMed1998

Intramuscular beta interferon for chronic hepatitis C: is it worth trying?

BACKGROUND AND AIMS: The intramuscular use of beta interferon has been tested in the treatment of chronic hepatitis C, but it did not prove effective when the schedule was 3 million units three times a week for six months. Since the lack of effectiveness of this treatment might be due to the low bioavailability of beta interferon when administered intramuscularly, we tested a higher dosage of the drug: 6 million units three times a week for twelve months. PATIENTS AND METHODS: Ninety-two patients were randomized to receive, intramuscularly, either 3 or 6 million units of natural human fibroblast beta interferon three times a week for 12 months. RESULTS: The short-term biochemical response was significantly more frequent in the group of patients who received the higher dosage of beta interferon: 21% vs 4.5% (p < 0.05). Nevertheless, a sustained biochemical response was obtained in only one patient (2%), who received the higher dosage of beta interferon. CONCLUSIONS: Since the better short-term response rate was obtained with the higher dosage of beta interferon, a further increase in the dosage might improve the short-term and, possibly, the long-term response to treatment. However, due to the high cost of beta interferon, this high-dose schedule would probably not be cost-effective in the treatment of chronic hepatitis C.

Adult↗
PubMed1998

[Response of interleukin-6 in patients undergoing a laparoscopic or laparotomic cholecystectomy].

BACKGROUND: It is well known that surgery induces an acute inflammatory response associated with significant increase of interleukin-6 (IL-6) and C reactive protein (CRP). Laparoscopic cholecystectomy (LC) is a so called "mini-invasive" surgical intervention and on the basis of this consideration it has been investigated if and how serological markers of inflammation are modified in patients after laparoscopic cholecystectomy compared to patients undergoing open cholecystectomy. METHODS: The acute phase of inflammation (IL-6, CRP and body temperature) was evaluated in 53 patients one day before surgery and p.o. after 1, 3 and 6 days; 26 patients underwent "open" cholecystectomy and 27 LC. RESULTS: One day after surgery patients with open cholecystectomy showed significant increase (p < 0.05) of IL-6, CRP and body temperature, while these parameters were almost unchanged in patients with LC. In patients with "open" cholecystectomy, 2 p.o. complications (pneumonia) were observed. CONCLUSIONS: In conclusion, LC, although it requires longer operative time, strongly reduces p.o. pain, hospitalization, promotes earlier recovery and return to normal activity, avoiding the acute phase of p.o. inflammation with better p.o. morbidity compared to open surgery.

Adult↗
PubMed1998

Extradural hematomas in children.

BACKGROUND: Extradural hematomas are rate complications of head injures in children often resulting from minor head traumas. Therefore the management of these ordinary traumas remains controversy since in many asymptomatic cases the intracranial bleeding is detected only by CT scan. METHODS: During the study period between January 1991 and September 1995 sixty-one patients ranging in age from 5 months to 12 years were operated on for epidural hematomas. They represent about the 3% of all patients admitted for head injury in the same period in our Division. According to the age, children were divided in three groups (G1, G2, G3). Males predominate over females in each group of age. The mechanism of injury, the clinical findings, the neurological assessment on admission, the site of hematoma and the presence of skull fracture were examined in order to identify clinical and diagnostic parameters predicting developing intracranial complications. RESULTS: The most common cause of head trauma was accidental falls in children under 5 years of age. Otherwise bicycle, pedestrian and car accidents are the main type of injury in older patients. A skull fracture was identified in 49 cases with a homogeneous distribution among the groups of age. Recurrent vomiting was found in about 70% of cases. A loss of consciousness was frequently reported (78%) in older children. Outcome mainly depended on Glasgow or Children Coma Score on admission. In our series the overall mortality rate was 4.9%. CONCLUSIONS: Our data according with the literature suggest that localized skull traumas, suspected fractures, a loss of consciousness after trauma and recurrent vomiting can be recommended as indications for intracranial complications.

Child↗
PubMed1998

Occipital remolding for correction of scaphocephaly in the young infant. Technical note.

BACKGROUND: Several surgical techniques have been described for correction of scaphocephaly. Recent advances in the field of craniofacial surgery have allowed more extensive operative procedures for the treatment of cranial vault anomalies. In general the aim of surgical treatment is to prevent early refusion of the parietal bones after the sagittal craniectomy associated with the widening of the biparietal diameter. In children older than 6 months these procedures may result unsatisfactory providing only a partial correction of the malformation. Therefore operative techniques of total cranial vault reshaping are reported in the literature. METHODS: We performed a surgical procedure of biparietal widening and occipital remolding in eight 3 month old infants with a marked deformation of the occipital prominence from sagittal synostosis. RESULTS: This technique has provided excellent cosmetic results with an immediate correction of the parieto-occipital malformation. There have not been intraoperative complications and the postoperative course was uneventful. CONCLUSIONS: The occipital remolding is useful in young infants with a marked skull deformity; this technique will produce immediate restoration of an esthetically pleasing cranial shape and a more satisfactory cosmetic result compared to less extensive procedures.

Cranial Sutures↗
PubMed1997

Acute cerebellar ataxia in children.

Acute cerebellar ataxia is a benign syndrome usually occurring after an acute febrile disease. In a few cases neuroradiological investigations reveal cerebellar alterations. Clinical and neuroradiological involvement of the brain stem has rarely been reported in the literature. We present five cases of acute cerebellar ataxia. In two cases the cerebellar symptomatology was associated with neurological signs of brain stem involvement. CT scans did not show any pathologic findings in three patients. MRI disclosed cerebellar or brain stem alterations in all the patients. Clinical and neuroradiological findings allow differentiation of this pathologic entity from other demyelinating or dysmyelinating diseases. The value of MRI in detection and localization of the lesions and in following their evolution is emphasized.

Acute Disease↗
PubMed1997

Control of postoperative pain by transcutaneous electrical nerve stimulation after thoracic operations.

BACKGROUND: Transcutaneous electrical nerve stimulation (TENS) has been used extensively to control postoperative pain, but its effects are controversial. This is probably due to the different types of operations performed and, therefore, to the varying intensity of postoperative pain. Here we present an extensive study with TENS in 324 patients who underwent different types of thoracic surgical procedures: posterolateral thoracotomy, muscle-sparing thoracotomy, costotomy, sternotomy, and video-assisted thoracoscopy. METHODS: Each patient cohort was randomly subdivided into three treatment groups: TENS, placebo TENS and control. The effectiveness of TENS was assessed by two factors: the time from the beginning of treatment to the request for further analgesia and the total medication intake during the first 12 hours after operation. RESULTS: Whereas posterolateral thoracotomy produced severe pain, muscle-sparing thoracotomy, costotomy, and sternotomy caused moderate pain, and video-assisted thoracoscopy caused only mild pain. The TENS treatment was not effective in the posterolateral thoracotomy group, but it was useful as an adjunct to other medications in the muscle-sparing thoracotomy, costotomy, and sternotomy groups. In contrast, representing the only pain control treatment with no adjunct drugs, it was very effective in patients having video-assisted thoracoscopy. CONCLUSIONS: These findings show that TENS is useful after thoracic surgical procedures only when postoperative pain is mild to moderate; it is uneffective for severe pain.

Endoscopy↗
PubMed1997

Postoperative pain and superficial abdominal reflexes after posterolateral thoracotomy.

BACKGROUND: Posterolateral thoracotomy can produce stretching of/or damage to the intercostal nerves and their branches. To assess intercostal nerve impairment after operation, we measured the superficial abdominal reflexes, which are mediated, at least in part, by the most inferior intercostal nerves. METHODS: Using electrophysiologic techniques, we made recordings from the left and right abdominal walls to study the responses evoked by mechanical stimulation of the skin after operation. In addition, we assessed postoperative pain intensity according to a numeric rating scale and recorded postoperative opioid dose. RESULTS: We found that the patients with complete disappearance of the superficial abdominal reflexes experienced more severe postoperative pain than those in whom the reflexes were maintained. Moreover, opioid treatment was less effective in the patients with no reflexes postoperatively. CONCLUSIONS: Our findings show a strict correlation between pain intensity after posterolateral thoracotomy and absence of abdominal reflexes. We suggest that the higher pain intensity together with the absence of reflexes may be due to intercostal nerve impairment, be it anatomic or functional, and thus to a larger neuropathic component of postoperative pain. This finding may be used as a predictor of patients with high analgesic requirements.

Electrophysiology↗
PubMed1997

Recurrence of thymoma: analysis of clinicopathologic features, treatment, and outcome.

OBJECTIVE AND METHODS: This study reports clinicopathologic features, treatment, and outcome of 30 recurrent thymomas out of 266 totally resected thymomas. RESULTS: The mean disease-free interval to recurrence was 86 months. Recurrence occurred less frequently and after a longer disease-free interval after resection of encapsulated versus invasive thymomas. The presence of associated myasthenia gravis did not affect recurrence proportion, disease-free interval, or survival after recurrence. A local recurrence occurred in 11 patients, 17 patients had a distant recurrence, and the extent of the recurrence could not be determined in 2 cases. Surgical treatment of the recurrent tumor was attempted in 16 cases, and a total resection was possible in 10 cases; exclusive radiotherapy was done in 11 cases. Overall 5- and 10-year survivals were 48% and 24%, respectively. In a univariate analysis, survival was significantly better in the presence of a local recurrence and in case of a total resection of the recurrent tumor. The use of adjuvant therapy after the resection of the initial thymoma had no effect on reducing the incidence of recurrence, in prolonging the disease-free interval, or in improving survival after the development of the recurrence. In a multivariate survival analysis, significant prognostic factors were the presence of a local recurrence and total resection of the recurrent tumor. CONCLUSIONS: Surgical resection is recommended in patients with recurrent thymoma. Local recurrence and total resection of the recurrent tumor are associated with excellent prognosis. A poor prognosis may be anticipated in the presence of distant recurrence and when radical surgical treatment is not done.

Adult↗
PubMed1997

Blockade of nocebo hyperalgesia by the cholecystokinin antagonist proglumide.

In patients who reported mild postoperative pain, we evoked a nocebo response, a phenomenon equal but opposite to placebo. Patients who gave informed consent to increase their pain for 30 min received a substance known to be non-hyperalgesic (saline solution) and were told that it produced a pain increase. A nocebo effect was observed when saline was administered. However, if a dose of 0.5 or 5 mg of the cholecystokinin antagonist proglumide was added to the saline solution, the nocebo effect was abolished. A dose of 0.05 mg of proglumide was ineffective. The blockade of the nocebo hyperalgesic response was not reversed by 10 mg of naloxone. These results suggest that cholecystokinin mediates pain increase in the nocebo response and that proglumide blocks nocebo through mechanisms not involving opioids. Since the nocebo procedure represents an anxiogenic stimulus and previous studies showed a role for cholecystokinin in anxiety, we suggest that nocebo hyperalgesia may be due to a cholecystokinin-dependent increase of anxiety.

Analgesics, Non-Narcotic↗
PubMed1997

Are alanine aminotransferase, hepatitis B virus DNA or IgM antibody to hepatitis B core antigen serum levels predictors of histological grading in chronic hepatitis B?

Paired sera and liver biopsies from 105 patients with chronic hepatitis B virus infection (34 HBeAg positive and 71 anti-HBe positive) were studied to investigate the relation between the degree of histological activity and alanine aminotransferase (ALT), hepatitis B virus DNA (HBV-DNA) or IgM antibody to hepatitis B core antigen (IgM anti-HBc) levels. ALT levels were significantly higher in patients with piecemeal necrosis (155 +/- 124 vs 75 +/- 42, p = 0.0017), but there were no differences in the ALT values of patients with or without intralobular necrosis. ALT values were within normal range in 29% of 31 patients without versus 15% of 65 with piecemeal necrosis (p = 0.19). Serum HBV-DNA levels were not related to the grade of lobular or portal/periportal activity in HBeAg-positive patients. Anti-HBe-positive subjects with piecemeal necrosis had higher HBV-DNA levels (34 +/- 93 vs 4 +/- 6, p = 0.01). IgM anti-HBc indexes were significantly higher in patients with intralobular necrosis (0.635 +/- 0.600 vs 0.356 +/- 0.367, p = 0.0005) or piecemeal necrosis (0.671 +/- 0.633 vs 0.321 +/- 0.219, p = 0.0002). In summary, since serum IgM anti-HBc-IMx indexes can reflect the grade of histological activity, the quantitative assessment of this antibody could be useful for non-invasive monitoring of hepatocellular damage in chronic hepatitis B.

Adult↗
PubMed1997

Use of 111In-DTPA-octreotide scintigraphy in the diagnosis of neuroendocrine and non-neuroendocrine tumors of the lung. Preliminary results.

BACKGROUND: The authors report their preliminary experience and results of the use of 111In-DTPA-octreotide scintigraphy (octreoscan) in the staging of neuroendocrine and non-neuroendocrine tumors of the lung. MATERIALS AND METHODS: From July 1995 to May 1996 twenty-six scintigraphic studies were performed in patients affected by lung cancer at the Department of Thoracic Surgery and at the Service of Nuclear Medicine of the University of Turin. RESULTS: Scintigraphy made it possible to detect the lesion in all the patients affected by neuroendocrine tumors and in 63.2% of the patients affected by non-neuroendocrine neoplasm of the lung. Scintigraphy also revealed mediastinal lymphnodal metastases in patients in which thoracic CT scan was negative: this result was confirmed by postoperative TNM. CONCLUSIONS: The authors stress the importance of 111In-DTPA-octreotide scintigraphy in a correct procedure of staging of neuroendocrine and non-neuroendocrine tumors of the lung and in the follow-up of neoplastic patients.

Adenocarcinoma↗
PubMed1997

[Video laparoscopic cholecystectomy in acute cholecystitis: when,how and why?].

Acute cholecystitis has been previously considered as contraindication for laparoscopic cholecystectomy (LC), but recently, several studies have demonstrated that the laparoscopic approach can also be effective in such cases, although iatrogenic lesions of the biliary tree have been increasingly reported. Aim of this study was to verify the effectiveness of LC in patients presenting with acute cholecystitis on the basis of preoperative and intraoperative findings, postoperative mortality and morbidity, in order to assess those conditions which still can be considered as contraindications for LC. From September 1992 to January 1995, 133 patients have been consecutively admitted and operated for LC. 46 cases (36.5%) had histologically proven acute cholecystitis. Moreover we have compared preoperative date (clinical history, laboratory findings, Rx and ultrasound evaluation) with intraoperative findings to assess a correlation with intraoperative difficult conditions evaluated according to De Manzini score. Our results demonstrate that clinical data significantly correlate with intraoperative difficult situations. Hepatobiliary ultrasound also has shown good correlation between the thickness of gallbladder wall and difficult operations (73.9 sensibility-70.1 specificity). Therefore, in patients with clinically severe acute cholecystitis, and thickened gallbladder demonstrated by ultrasound it is very likely that the surgeon will experience difficult in intraoperative situations. In these conditions laparoscopy may be considered mainly as a diagnostic procedure in order to evaluate the entity of inflammatory changes considering the possibility of an open conversion that must be done before any iatrogenic lesion occur. This policy has allowed us to avoid in our series postoperative complications such as lesions of the biliary tree. In conclusion we believe that LC for acute cholecystitis should be considered as a therapeutical option only for selected cases.

Acute Disease↗