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Biomedical subjects

M Campani

Publications and source records attributed to M Campani.

13 recordsLinked to original sources

CCD imaging of the electrical activity in the leech nervous system.

A single ganglion of the nervous system of the leech Hirudo medicinalis was isolated. One or both roots emerging from each side of the ganglion were sucked into suction pipettes used either for extracellular stimulation or for recording the gross electrical activity. The ganglion was stained with the fluorescence voltage sensitive dye Di-4-Anepps. The fluorescence was measured with a nitrogen cooled CCD camera. Our recording system allowed us to measure in real time slow optical signals corresponding to changes in light intensity of at least 5/1000. These signals were caused by the direct polarization of neuronal structures, the afterhyperpolarization or the afterdischarge induced by a prolonged stimulation. When images were acquired at fixed times, several of them could be averaged and optical signals of at least 2/1000 could be reliably measured. These optical signals originated from well identified neurons, such as T, P and N sensory neurons. By taking images at different times and at different focal planes, electrical events could be followed at a temporal resolution of 50 Hz. The three dimensional dynamics of electrical events, initiated by a specific stimulation, was imaged and the spread of excitation among leech neurons was followed. When two roots were selectively stimulated, their neuronal interactions could be imaged and the linear and non-linear terms of the interaction could be characterized.

Animals

Optic flow and autonomous navigation.

Many animals, especially insects, compute and use optic flow to control their motion direction and to avoid obstacles. Recent advances in computer vision have shown that an adequate optic flow can be computed from image sequences. Therefore studying whether artificial systems, such as robots, can use optic flow for similar purposes is of particular interest. Experiments are reviewed that suggest the possible use of optic flow for the navigation of a robot moving in indoor and outdoor environments. The optic flow is used to detect and localise obstacles in indoor scenes, such as corridors, offices, and laboratories. These routines are based on the computation of a reduced optic flow. The robot is usually able to avoid large obstacles such as a chair or a person. The avoidance performances of the proposed algorithm critically depend on the optomotor reaction of the robot. The optic flow can be used to understand the ego-motion in outdoor scenes, that is, to obtain information on the absolute velocity of the moving vehicle and to detect the presence of other moving objects. A critical step is the correction of the optic flow for shocks and vibrations present during image acquisition. The results obtained suggest that optic flow can be successfully used by biological and artificial systems to control their navigation. Moreover, both systems require fast and accurate optomotor reactions and need to compensate for the instability of the viewed world.

Computer Simulation

Selective bronchial intubation for one lung anaesthesia in thoracic surgery. A new method.

A new method for one lung anaesthesia in thoracic surgery is described. Separate lung ventilation is obtained with selective main bronchus intubation, by means of an appropriate cuffed tube inserted through a standard orotracheal tube. Ventilation is carried out separately through the bronchial tube on one side and the residual tracheal tube lumen on the other side. This method greatly simplifies the technique of bronchial intubation and offers many advantages over commercially available double-lumen tubes.

Anesthesia, Inhalation

Preoperative prediction and quantification of septic risk caused by malnutrition.

Evaluation of the nutritional status of surgical patients was carried out by means of cluster analysis of several indicators to identify different nutritional conditions that could be considered frames of reference for the prediction of postoperative infections. Seventy-one surgical patients entered into the first phase of the study that identified four nutritional situations with a different incidence of postoperative sepsis; cluster 1 showed the lowest incidence of infectious episodes, and clusters 2 to 4 were characterized by a higher incidence of sepsis and other complications. In the second phase of the study, 28 patients were examined and compared with the four reference states by means of the determinations of the euclidean distance between the nutritional assessment of the patient and the barycenter of each of the reference states. The incidence of sepsis was similar in the two series of patients, indicating that the characterization of patients in one of the four reference states allows one to predict the risk of postoperative septic complications.

Adult

[Immunological monitoring of patients operated on for epidermoid bronchogenic carcinoma].

Sequential monitoring of non specific immunity has been carried out in 16 patients with squamous cell bronchogenic carcinoma undergoing radical surgery. At the time of diagnosis total lymphocyte counts, T-lymphocyte counts and the blastogenic response of lymphocytes to PHA were only slightly depressed; on the contrary C3c and C4 serum levels were significantly increased (P less than 0.01). Sequential determinations of the immunologic profile at monthly intervals up to the 12th postoperative month showed a transient increase of total lymphocyte and T-lymphocyte levels; the lymphocyte blastogenic response to PHA and also C3c and C4 serum levels progressively decreased. Delayed hypersensitivity response to cutaneous antigens, neutrophil chemotaxis, serum levels of IgG, IgA, IgM and B-lymphocyte counts were constantly found within normal range.

Adult

Postoperative infections and variations of complement components in cancer patients.

Sequential determinations of C4 and factor B serum levels were performed pre- and postoperatively in 56 cancer patients. Patients who underwent radical mastectomy and excision of melanoma had an incidence of surgical infections of 7% and 15%, respectively, and showed a significant postoperative acute-phase increase of C4 and factor B serum levels. A higher incidence of postoperative infections, mostly Gram negative, was recorded in patients who underwent gastric resection (35%) and colorectal resection (73%); these failed to show an early acute-phase response of complement postoperatively. The results of this study confirm the high susceptibility of cancer patients to postoperative infections. Moreover, the lack of postoperative acute-phase increase of C4 and factor B observed in cancer patients who developed postoperative infections suggests an active role of complement in host defense mechanisms against surgical infections.

Adult

Sequential evaluation of immunoreactivity in patients with melanoma undergoing surgery and adjuvant therapy.

The immunologic profile of 15 patients undergoing surgery and adjuvant chemoimmunotherapy for cutaneous melanoma was studied for a mean period of 18 months. In vivo cellular immunity was assayed by evaluation of delayed hypersensitivity response (DHR) to primary antigen and a panel of recall antigens. In vitro cellular immunity was evaluated to means of total and T-lymphocyte counts in peripheral blood and by the lymphocyte blastogenic response to phytohemagglutinin stimulation. Humoral immunity was assayed by determining the serum levels of IgG, IgA and IgM and of complement components C3c, C4 and Factor B. Phagocytic activity was studied by testing leukocyte chemotaxis, neutrophil phagocytosis and leukocyte random migration. The in vitro parameters were determined preoperatively at diagnosis, 6 times during the first 2 postoperative weeks, and then every month during adjuvant therapy. No correlation was found between DHR and clinico-pathologic stage of tumor, or with subsequent clinical course. Significant depression of total lymphocyte and T-lymphocyte count and blastogenic response of lymphocytes was found at diagnosis. The lymphocyte response to PHA decreased significantly in the early postoperative period but returned to preoperative levels one week after surgery. Periodic fluctuations of lymphocyte blastogenic response and progressive decrease of total lymphocyte counts and T-lymphocyte counts were observed during the 18-month follow-up. No significant alterations of immunoglobulin levels were recorded at diagnosis or during the postoperative period. Complement levels were within normal values preoperatively; in the early postoperative period a transient increase of C3c, C4 and Factor B was recorded, then complement levels progressively decreased. Parameters of phagocytic activity were normal at diagnosis and fluctuated within the normal range throughout the whole period of study.

Adult

Clinical-pharmacological aspects, application and effectiveness of total parenteral nutrition in surgical patients.

The term "total parenteral nutrition" (TPN) refers to the maintenance of an adequate nutritional status, normal body weight and positive nitrogen balance solely by intravenous means. It requires solutions providing calories, amino acids and other nutrients in amounts much greater than those indicated for maintenance of normal body weight. Nutrient solutions have been studied, selected and prepared in our Hospital Pharmacological Service utilizing a sterile closed system, which allows large-volume filtering, sterilizing and bottling devices. For maintenance of weight gain in adults, a basic formula is employed, which provides 1,100 Kcal/1 with pure crystalline amino acids mixed with 50% anhydrous dextrose in water in a ratio of 5.8:1 (160 Kcal:1 g nitrogen). Minerals and vitamins are added to the base solution prior to use and may be increased or decreased by simple addition or omission depending on the patient's condition. This paper is based on 192 surgical patients who received TPN and have been followed in strict cooperation between the Hospital Pharmacological Service and the Surgical Department. The patients, ranging from 23 to 79 years of age, with life threatening diseases and unable to maintain adequate nutrition by the oral route, received TPN through a central catheter inserted via subclavian puncture (146 cases) or through a surgically created internal A-V fistula (46 cases). The condition of the patients generally improved within a few days after starting TPN; and weight gain, wound healing, general improvement and a shorter period of hospitalization were observed. TPN could be efficiently combined with oncologic treatment, and a significant improvement of the patients' performance status and decrease of toxic side-effects due to chemotherapeutic agents were observed. TPN has been successfully applied also in patients with fistulas of the alimentary tract obtaining spontaneous closure and in patients with ulcerative colitis, showing its beneficial effect in allowing complete bowel rest for healing. No major complications or deaths could be attributed to TPN or to the route of administration.

Adult