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Biomedical subjects

P Tonino

Publications and source records attributed to P Tonino.

9 recordsLinked to original sources
PubMed2000

The anesthetic and recovery profile of two doses (60 and 80 mg) of plain mepivacaine for ambulatory spinal anesthesia.

UNLABELLED: Reports of transient neurological symptoms with the use of subarachnoid lidocaine has generated interest in alternate local anesthetics of intermediate duration, such as mepivacaine. This prospective randomized, double-blinded, dose-response study examined the anesthetic and recovery profiles of 60- and 80-mg doses of preservative-free plain mepivacaine for ambulatory spinal anesthesia. Sixty patients undergoing ambulatory anterior cruciate ligament repair of the knee under spinal anesthesia were randomized into two groups; Group 1 (29 patients) received 4 mL of 1.5% (60-mg dose) and Group 2 (31 patients) received 4 mL of 2% (80-mg dose) of plain mepivacaine. All patients received a combined spinal-epidural anesthetic technique. The epidural catheter was used only in the event the surgery outlasted the duration of surgical anesthesia with subarachnoid mepivacaine. Epidural supplementation was administered in three patients (12%) in Group 1 and one patient (3%) in Group 2 when the sensory block regressed to L-1 with surgery expected to last longer than 15 min. The cephalad dermatome level of the block and degree of motor block was comparable in the two groups. Times to two-segment and T-10 regression were comparable in the two groups (112 +/- 26 min in Group 1 versus 122 +/- 28 min in Group 2). Time to L-1 regression was significantly longer in Group 2 (146 +/- 28 min in Group 1 versus 159 +/- 19 min in Group 2). All of the ambulatory milestones were significantly faster in Group 1. Side effects, such as hypotension and emesis were negligible, severe bradycardia and urinary retention did not occur, and none of the patients in the two groups reported transient neurological symptoms over 24 h. In conclusion, plain mepivacaine in a 60- or 80-mg dose is a suitable local anesthetic choice for ambulatory spinal anesthesia with respect to anesthetic, as well as recovery profiles. IMPLICATIONS: We evaluated the anesthetic and recovery profiles of 60- and 80-mg doses of plain mepivacaine for ambulatory spinal anesthesia. Both doses produced comparable sensory and motor block. Sensory and motor regression and ambulatory milestones were 20-30 min longer with the 80-mg dose. Side effects were negligible and transient neurological symptoms were not reported during a 24-h follow-up.

Adolescent↗
PubMed1997

Microvascular pathology in the skeletal muscle paraneoplastic phenomenon.

An electron microscopic investigation was made in order to study capillary alterations in the muscle paraneoplastic phenomenon associated with different malignant tumours. Several abnormalities were found including basement membrane widening and lamination, endothelial hypertrophy, a varied degree of lumen occlusion, and proliferative changes in pericytes. A degenerative process leading to capillary necrosis was also observed. A mononuclear cell infiltrate formed by macrophages, lymphocytes and mast cells was seen. The capillary changes observed suggest the existence of an autoimmune vascular factor in the etiopathogenesis of muscle damage in this phenomenon.

Capillaries↗
PubMed1997

Ultrastructure of hepatic metastases from a colon leiomyosarcoma.

The electron microscopic examination of biopsies from liver metastases of a colon leiomyosarcoma showed the existence of alterations not previously reported in primary tumors of that kind. Those abnormalities included proliferation of lysosomal structures as multivesicular bodies, myelin-like figures, lipofuscin granules and autophagic vacuoles, along with mitochondrial changes as concentric and vesiculated cristae, and presence of dense granules and elongated inclusions. This study suggests that, in this tumor and host tissue, the so-called invasive phenotype, which is supposed to form the metastases, could have a distinct morphological picture at the ultrastructural level.

Colonic Neoplasms↗
PubMed1996

Interleukin 1 (IL-1)-dependent melanoma hepatic metastasis in vivo; increased endothelial adherence by IL-1-induced mannose receptors and growth factor production in vitro.

BACKGROUND: The growth of cancer cells in inflammatory tissue is often observed. This can be the result of favorable conditions for endothelial cell adherence and/or increased production of local growth factors. PURPOSE: The role of the proinflammatory cytokine interleukin 1 (IL-1) in the prometastatic and growth-promoting environment of inflammation was studied in vivo, and the mechanism of cytokine action was studied in vitro as well. METHODS: Systemic inflammation was induced by the intravenous injection of IL-1 beta or lipopolysaccharide (LPS), and the hepatic metastasizing ability of B16 melanoma (B16) cells following intrasplenic injection was studied. IL-1 receptor blockade was accomplished with the use of the IL-1 receptor antagonist (IL-1Ra). In vitro, IL-1Ra was used to assess the mechanism for prometastasis and growth promotion of cultured hepatic sinusoidal endothelium stimulated with LPS. RESULTS: There was a statistically significant (P < .01) enhancement in the parameters of hepatic metastasis when B16 cells were injected intrasplenically either 4 hours after IL-1 injection or 6 or 12 hours after LPS injection. IL-1Ra pretreatment reduced IL-1-induced enhancement of metastasis by 73%-87% and completely inhibited the augmentation of metastasis following LPS injection. In vitro, the adherence of melanoma cells to LPS-treated endothelium increased nearly twofold but was completely abrogated when IL-1Ra was added before LPS. Similar to melanoma adherence, a 2.5-fold increase (P < .05) in functional mannose receptors was observed with LPS treatment but was prevented by the addition of IL-1Ra did not affect basal mannose-receptor activity in unstimulated epithelium. Mannose-receptor activity and B16 cell adherence significantly correlated (r = .9) with LPS treatment. Conditioned medium from LPS-stimulated epithelium augmented B16 cell proliferation compared with control conditioned medium (P < .01). Production of B16 cell growth factor(s) was markedly reduced (P < .01) when IL-1Ra was added. CONCLUSIONS: These results demonstrate that systemic inflammation induces an enhancement of melanoma cell metastasis and growth by IL-1-dependent mechanisms in vivo. In vitro, the mechanism(s) is consistent with IL-1-mediated increase in expression of mannose receptors and production of tumor cell growth factor(s) from the endothelium. IMPLICATIONS: Given the multiple and complex cytokine cascade induced in vivo and in vitro during LPS-induced systemic inflammation, IL-1 plays a strategic role. Since IL-1Ra is without side effects in humans, studies on intraoperative infusion of IL-1Ra during tumor resection may be indicated.

Animals↗
PubMed1996

Tourniquet-induced exsanguination in patients requiring lower limb surgery. An ischemia-reperfusion model of oxidant and antioxidant metabolism.

BACKGROUND: Surgically induced ischemia and reperfusion is frequently accompanied by local and remote organ injury. It was hypothesized that this procedure may produce injurious oxidants such as hydrogen peroxide (H2O2), which, if unscavenged, will generate the highly toxic hydroxyl radical (.OH). Accordingly, it was proposed that tourniquet-induced exsanguination for limb surgery may be a useful ischemia-reperfusion model to investigate the presence of oxidants, particularly H2O2. METHODS: In ten patients undergoing knee surgery, catheters were placed in the femoral vein of the limb operated on for collection of local blood and in a vein of the arm for sampling of systemic blood. Tourniquet-induced limb exsanguination was induced for about 2 h. After tourniquet release (reperfusion), blood samples were collected during a 2-h period for measurement of H2O2, xanthine oxidase activity, xanthine, uric acid (UA), glutathione, and glutathione disulfide. RESULTS: At 30 s of reperfusion, H2O2 concentrations increased (approximately 90%) from 133 +/- 5 to 248 +/- 8 nmol.ml-1 (P < 0.05) in local blood samples, but no change was evident in systemic blood. However, in both local and systemic blood, xanthine oxidase activity increased approximately 90% (1.91 +/- 0.07 to 3.93 +/- 0.41 and 2.19 +/- 0.07 to 3.57 +/- 0.12 nmol UA.ml-1.min-1, respectively) as did glutathione concentrations (1.27 +/- 0.04 to 2.69 +/- 0.14 and 1.27 +/- 0.03 to 2.43 +/- 0.13 mumol.ml-1, respectively). At 5 min reperfusion, in local blood, H2O2 concentrations and xanthine oxidase activity peaked at 796 +/- 38 nmol.ml-1 (approximately 500%) and 11.69 +/- 1.46 nmol UA.ml-1.min-1 (approximately 520%), respectively. In local blood, xanthine and UA increased from 1.49 +/- 0.07 to 8.36 +/- 0.33 nmol.ml-1 and 2.69 +/- 0.16 to 3.90 +/- 0.18 mumol.ml-1, respectively, whereas glutathione and glutathione disulfide increased to 5.13 +/- 0.36 mumol.ml-1 and 0.514 +/- 0.092 nmol.ml-1, respectively. In systemic blood, xanthine oxidase activity peaked at 4.75 +/- 0.20 UA nmol.ml-1.min-1. At 10 min reperfusion, local blood glutathione and UA peaked at 7.08 +/- 0.46 mumol.ml-1 and 4.67 +/- 0.26 mumol.ml-1, respectively, while the other metabolites decreased significantly toward pretourniquet levels. From 20 to 120 min, most metabolites returned to pretourniquet levels; however, local and systemic blood xanthine oxidase activity remained increased 3.76 +/- 0.29 and 3.57 +/- 0.37 nmol UA.ml-1.min-1, respectively. Systemic blood H2O2 was never increased during the study. During the burst period (approximately 5-10 min), local blood H2O2 concentrations and xanthine oxidase activities were highly correlated (r = 0.999). CONCLUSIONS: These studies suggest that tourniquet-induced exsanguination for limb surgery is a significant source for toxic oxygen production in the form of H2O2 and that xanthine oxidase is probably the H2O2-generating enzyme that is formed during the ischemia-reperfusion event. In contrast to the reperfused leg, the absence of H2O2 in arm blood demonstrated a balanced oxidant scavenging in the systemic circulation, despite the persistent increase in systemic xanthine oxidase activity.

Adult↗
PubMed1996

Skeletal muscle pathology in mice experimentally infected with Toxoplasma gondii.

In two different groups of mice, the infection with Toxoplasma gondii was produced by intraperitoneal route, with 2 x 10(5) parasites (n = 8) and 14 x 10(5) parasites (n = 3). Five days after infection animals were killed to examine skeletal muscles by light and transmission electron microscopy. Severity of muscle alterations depended upon concentration of parasites. Parasite cysts were not identified in muscle sections. Ultrastructural features revealed different degrees of fibre atrophy, alterations in the sarcomeric structure and, in some cases, disorganization of contractile and sarcotubular systems. Changes in muscular capillaries included loss of the endothelial wall, occlusion of lumen and necrosis. Motor end-plates were abnormal and axonolysis was present. A mononuclear cell infiltrate consisted of macrophages, lymphocytes, mastocytes and eosinophils were observed. In this murine model it was demonstrated that the infection of non-immunocompromised hosts with Toxoplasma gondii produces an acute myositis.

Animals↗
PubMed1993

Skeletal muscle capillary ultrastructure in Toxoplasma gondii parasitized mice.

A light and transmission electron microscopic study was performed in skeletal muscles from mice experimentally infected with Toxoplasma gondii. Parasite cysts were not observed. Capillary endothelial cytoplasm abnormalities included proliferation of organelles, decrease of pynocytic vesicles, degenerative changes and necrosis. In some capillaries the lumen was reduced or absent. Pericytes also were altered. In all animals (n = 13), the basement membrane was normal. The cellular infiltrate consisted of macrophages, lymphocytes, mastocytes and eosinophils. The alterations observed in muscle microvasculature in absence of Toxoplasma gondii cysts, could be due to a host-immune response to the parasite.

Animals↗
PubMedDate not supplied

Strength testing after third-degree acromioclavicular dislocations.

Twenty male patients with a grade III acromioclavicular joint dislocation were evaluated more than 2 years after their injury; the average followup was 4.5 years. Strength testing was performed with a Cybex II dynamometer in three planes evaluating flexion, extension, internal rotation, external rotation, abduction, and adduction at 60 and 120 deg/sec. Subjective complaints were minor and neither daily activities nor athletic participation were impaired. Objectively, only one patient had tenderness over the acromioclavicular joint. All patients had full motion and negative impingement signs. Strength testing with the Cybex II dynamometer showed no significant difference (P less than 0.05) between the injured and uninjured shoulder for strength in internal rotation, external rotation, abduction, adduction, extension, or flexion at speeds of 60 and 120 deg/sec. This study shows that the strength of the shoulder is not significantly affected by conservative treatment of grade III acromioclavicular dislocations. Conservative treatment results in minimal or no functional deficit. The authors recommend that grade III acromioclavicular dislocations be treated nonoperatively.

Acromioclavicular Joint↗