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Biomedical subjects

F Papi

Publications and source records attributed to F Papi.

35 records · Page 2Linked to original sources
PubMed1991

Orientation in birds. Olfactory navigation.

Research work on the olfactory navigation of birds, which has only recently attracted attention, has shown that many wild species rely on an osmotactic mechanism to find food sources, even at a considerable distance. The homing pigeon, the only bird to have been thoroughly investigated with respect to olfactory navigation, has been found to rely on local odours for homeward orientation, and to integrate olfactory cues perceived during passive transportation with those picked up at the release site. It is possible to design experiments in which birds are given false olfactory information, and predictions about the effects of this can be made and tested. Pigeons are able to home from unfamiliar sites because they acquire an olfactory map extending beyond the area they have flown over. The olfactory map is built up by associating wind-borne odours with the direction from which they come; this was shown by experiments which aimed to prevent, limit or alter this association. One aim of the research work has been to test whether pigeons flying over unfamiliar areas also rely or can learn to rely on non-olfactory cues, depending on their local availability, and/or on the methods of rearing and training applied to them. Various evaluations have been made of the results; the most recent experiments, however, confirm that pigeons do derive directional information from atmospheric odours. A neurobiological approach is also in progress; its results show that some telencephalic areas are involved in orientation and olfactory navigation. The lack of any knowledge about the distribution and chemical nature of the odorants which allow pigeons to navigate hinders progress in this area of research.

Animals↗
PubMed1990

Pigeons with ablated pyriform cortex home from familiar but not from unfamiliar sites.

Homing behavior was tested in pigeons (Columba livia) after removing a portion of the ventrolateral telencephalon, which receives extensive projections from the olfactory bulb and is comparable with the mammalian pyriform cortex. Ablated pigeons show unaffected cardiac responses to odorous stimuli but altered homing behavior. After the operation, the birds were trained by repeated flock releases along with control birds from a site 40 km from the loft. After being released singly from this familiar site, the ablated birds turned out to be unaffected by the operation. In releases from two unfamiliar sites, ablated birds, unlike control birds, were not homeward oriented and were mostly lost. The ablation of the pyriform cortex has the same effect on homing behavior as olfactory deprivation. It can be concluded that the pyriform cortex plays an important role in the specific mechanisms linking olfactory inputs with the navigational response.

Animals↗
PubMed1989

Olfactory bulb size, odor discrimination and magnetic insensitivity in hummingbirds.

Relative olfactory bulb size with respect to telencephalic hemispheres (olfactory ratio) was measured in five species of hummingbirds. Trochiliformes were found to be next to last among 25 avian orders with respect to olfactory bulb development. One hummingbird species, the White-vented Violetear (Colibri serrirostris), was trained in a successive go/no-go discrimination task, and learned to feed or not to feed from a container dependent on the olfactory stimuli associated with it. Test birds learned to discriminate amyl acetate vs. turpentine essence, jasmine essence vs. lavender essence, eucalyptus essence vs. no odor, beta-ionone vs. no odor, carvone vs. eucalyptol. In contrast, 1-phenylethanol vs. beta-ionone discrimination, two odorants which appear similar to humans, was unsuccessful. Using a similar procedure, attempts were made to condition a White-vented Violetear and a Versicolored Emerald (Amazilia versicolor) to magnetic stimuli. The birds were unable to discriminate between a normal field and an oscillating field (square wave, 1 Hz, amplitude +/- 0.40 G).

Animals↗
PubMed1984

[The use of prostheses in recurrent hernias].

The use of inert plastic (Prolene mesh, 0,027 inches in thickness fournited by Ethicon) as preperitoneal prosthesis in repair of incisional hernias and inguinal hernia recurrencies has been investigated in 28 patients operated upon then 1977 to 1984. In 9 patients the inguinal approach was used with one recurrence (11%). In 9 patients the posterior approach through a midline incision has been used with two recurrences (22%). In 10 patients with incisional hernias there was only one recurrence (10%). Total recurrences rate was 14%. Most recurrences occur in patients operated from 1977 to 1980 (40%). Patients operated in the last period from 1980 to 1984 had no recurrences.

Adult↗
PubMed1984

[Anal sphincter function following colorectal anastomosis with a stapler by transperineal-sphincter approach].

In 4 patients who under went low anterior resection for cancer of mid and lower 1/3 of the rectum, with colo-rectal anastomosis by posterior transphinteric approach, anorectal pressure profiles have been studied by open tip technique 30 d. 6 months following operation. Bowel movements, gas and feces discrimination and anal continence were also controlled. Resting pressure, delta % pressure changes during recto-anal reflex, pressure in voluntary contraction, altered in the first post-operative period, become normal in 6 months. Although volume and pressure at urgent rectal sensation, volume and rectal sensation and compliance altered after surgery did not change after 6 months, suggesting that the reservoir function of the rectum is lost, patients achieved a good control of bowel movements, and a good gas and feces discrimination and anal continence within the first 6 months of operation.

Anal Canal↗
PubMed1984

[The use of mechanical suturing in colorectal anastomoses].

In 16 patients affected by cancer of the mild or lower 3 of the rectum, has been performed a colorectal anastomosis by EEA Stapler, with abdomino-transanal approach. In the postoperative period no case of anastomotic bleeding or stenosis has been observed. 3 patients (18%) presented minor anastomotic dehiscence detected by radiologic examination, without clinical symptomatology. The EEA Stapler anastomosis seem sure almost as the traditional hand sutures, and allow the execution of anterior resection instead of abdominal perineal amputation of rectum.

Adult↗
PubMed1984

[The use of mechanical suturing in esophago-jejunal anastomoses].

10 esophagojejunostomies by EEA Stapler were performed on adult patients (8 males and 2 females, mean age 54 years), after total gastrectomy for gastric cancer. No postoperative bleeding or stricture were observed. 2 anastomotic leaks occurred (20%). The major cause of anastomotic failure is probably technical (incorrect assembly or lubrication of the instrument). According to the our experience and to literary data, the use of stapling devices for performance of esophagojejunostomies is recommended.

Adult↗
PubMed1984

[Strain-gauge plethysmography in the evaluation of the evolution of deep vein thrombosis of the legs].

Previous research has shown that MVO (Maximum Venous Outflow), VR (Venous Reflux), VE (Venous Emptying) and the respiratory waves recording are useful in differentiating occlusion and recanalization in postphlebitic syndrome. In the present work strain-gauge plethysmography was employed to quantitate the venous function after deep venous thrombosis of the legs. The studies were performed in a vascular laboratory with controlled temperature (23 to 25 C); records were obtained by a plethysmograph Parks mod. 270 connected to a Hewlett-Packard multi-channel mod. 7700. 17 patients (12 males, 5 females), mean age 55 years (range 24-75) that presented femoropopliteal thrombophlebitis documented by phlebography at the admission to the hospital were examined. MVO with and without superficial veins occlusion was measured by a mercury in silastic strain-gauge placed circumferentially about the calf. A pneumatic cuff thigh was inflated to 60 mm Hg. VE was measured in patients lying in inclined bed with the lower extremities 100 cm below the heart level compressing the calf with a pneumatic cuff 10 times for 5 seconds; the strain-gauge was placed on the foot level. VR after Valsalva's maneuver and the respiratory waves were recorded by a strain-gauge positioned at the maximum girth about the calf in patients lying on inclinated bed with the lower extremities 50 cm below the heart level. The result are here indicated: (Table: see text) There was differences in the evolution of venous function after deep venous thrombosis of the legs for each patient. Strain-gauge plethysmography may become evaluable non invasive technique in the evaluation of deep venous thrombosis evolution in the legs. The therapeutic assessment of postphlebitic syndrome.

Adult↗
PubMedDate not supplied

Leptin serum levels are involved in the relapse after weight excess reduction in obese children and adolescents.

BACKGROUND: Leptin concentrations as a predictor of weight excess (WE) variations in obese children continue to be controversial. AIM AND DESIGN: To evaluate the relationship between fasting leptin serum concentrations and the ability to maintain loss of WE during obesity treatment, 172 (82 males and 90 females) overweight children and adolescents (OW), 6-16 yr old, were recruited. The subjects were retrospectively selected among those who had demonstrated a reduction of their WE during an initial phase of 12 months of a WE reduction programme (WERP). Fasting serum levels of leptin were assayed, together with insulin, triacylglycerol and cholesterol, before (time 0) and at the end of the first phase of WERP (time 1), and BMI (Z-score) was determined at time 0, time 1 and at the end (time 2) of a subsequent second phase of 12 months. OW were subdivided according to wether their Z-BMI showed a persistent reduction also during the second phase (maintaining WE reduction subjects or MS) or showed a subsequent increase after the reduction observed during the first phase (relapsing WE subjects or RS). RESULTS: A significant reduction in serum levels of leptin, insulin and lipids, paralleling Z-BMI reduction, was observed at the end of the first phase of WERP, during which we found a correlation between the decrease in serum leptin concentrations and the decrease in Z-BMI. The decrease in RS during the first phase ((deltalgL(0-1) was significantly greater when compared to that observed in MS (p < 0.05). In two different multiple logistic regression analyses, where RS = 0 and MS = 1, serum leptin at time 1 [odds ratio (OR) = 1.08; 95% confidence interval (CI) = 1.04-1.13] and deltalgL(0-1) (OR = 0.48; 95% CI = 0.25-0.92), together with final pubertal stage (OR = 0.78; 95% CI = 0.63-0.96), were significantly associated with final subject status. CONCLUSIONS: Leptin serum levels after a previous WE reduction and its parallel decline are related to subsequent adiposity outcome. The lower the leptin serum concentration after previous WE reduction and/or the greater its decrease, the greater was the probability of WE relapse.

Adolescent↗