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Biomedical subjects

L Negri

Publications and source records attributed to L Negri.

At least 91 records · Page 5Linked to original sources
PubMed1986

Satiety and scratching; effects of bombesin-like peptides.

Two novel amphibian peptides, [Ser7]litorin-like peptide (Ser-LIT) and [Ser7]bombesin-like peptide (Ser-BN), recently isolated from the skin of the South American frog Phyllomedusa sauvagei, are characterized by the occurrence of a Ser residue in place of His7 in the C-terminal tripeptide. For testing on food intake in fasted rats the peptides were injected intraperitoneally (i.p.) and intracerebroventricularly (i.c.v.) and their activity compared with that of bombesin (BN) and litorin (LIT). Ser-LIT was completely ineffective on food intake while Ser-BN was about ten times less potent than LIT by i.p. injection; given i.c.v., Ser-BN inhibited food intake in the first 15 min after injection but its effect faded within 60 min. The i.c.v. administration of both [Ser7]-substituted peptides, elicited intense scratching with a potency equal to or higher than that of BN or LIT. The existence of two different kinds of receptors for BN-like peptides may be hypothesized: the first, specific for the C-terminal tripeptide sequence, is apparently involved in the inhibition of feeding; the second, responsible for the stimulating activity on the urinary bladder and for scratching, shows higher affinity for the N-terminal portion of the biological active sequence.

Animals↗
PubMed1985

Combined cryosurgical, chemotherapeutic, and radiotherapeutic management of T1-4N0M0 oral cavity cancers.

Eighty-four previously untreated patients (69 males, 15 females) with squamous carcinoma of the tongue (30 patients), floor of the mouth (30), cheek (16), and retromolar region (8) were treated using a protocol comprising cryosurgery + chemotherapy, followed by external 60Co radiotherapy. The follow-up period was at least 6 months (median, 50 months). Cryosurgery (1-2 sessions in 49 T1-2 cases; 2-4 in 35 T3-4 cases) was accompanied by a CMF (cyclophosphamide, methotrexate, 5-fluorouracil) schedule (T1-2, two courses; T3-4, three courses). Radiotherapy was given 15 to 20 days after combined cryochemotherapy (T1, 50 Gy on tumor and lymph nodes; T2-3-4, same with an extra dose of 10 to 15 Gy on the primary lesion). Complete remission was reached 4 months after treatment in 76 of 84 patients (90.5%). Survival with no evidence of disease (NED) in the 57 patients (27 T1-2, 30 T3-4) with a follow-up of more than 3 years was 59.6% for the series as a whole, 70.3% for T1-2, and 50.0% for T3-4; 78.2% for the tongue, 52.6% for the floor, 66.6% for the cheek, and 0% for the retromolar region. The picture was much the same after 5 years. Actuarial survival at 6 years was 66% in the series as a whole, 75.5% in T1-2, and 57.5% in T3-4 (tongue 86.9%, floor 56.1%, cheek 68.4%, and retromolar region 0%). It is believed that the results obtained in tumors of the tongue, floor and cheek, coupled with the conservative aspects of the protocol, make it a suitable subject for a controlled trial.

Adult↗
PubMed1985

Tolerance and physical dependence induced by dermorphin in rats.

Rats chronically implanted with osmotic minipumps in the left lateral ventricle were used to study the ability of dermorphin to produce tolerance and physical dependence. The development of tolerance, assessed by evaluating the time reduction of analgesia, catalepsy and rigidity, occurred in a dose-dependent fashion over a maximum period of 48 h. After 3 days of peptide infusions into the rat brain, the dependent state was established and was revealed by precipitating the withdrawal syndrome with intraperitoneal naloxone injections. Escape behavior, shaking, salivation and rhynorrhea were the main symptoms, qualitatively similar to those obtained in rats made dependent on morphine. Considering that dermorphin displays strong analgesic activity, the well-known combination of antinociception tolerance and dependence capacities of opiates also seems to be valid for dermorphin.

Animals↗
PubMed1985

Effects of sauvagine, urotensin I and CRF on food intake in rats.

Sauvagine (SV) is a forty amino acid peptide, isolated from the skin of the South American frog Phyllomedusa sauvagei and structurally related to fish Urotensin I (U1) and to mammalian corticotropin releasing factor (CRF). Intracerebroventricular (ICV) injections of SV (0.3-2.0 micrograms/rat), CRF (1.0-15.0 micrograms/rat) and U1 (0.5-2.0 micrograms/rat) inhibited feeding in 18 hr food deprived rats. By subcutaneous (SC) route, only SV (3.0-10.0 micrograms/kg) and U1 (10.0-20.0 micrograms/kg) exhibited anorexogenic effects, CRF being completely inactive up to a dose of 200 micrograms/kg. Vagotomy did not prevent the feeding inhibition by SC SV. In ICV injected rats, CRF increased grooming in comparison with both food deprived and satiated controls, while SV and U1 increased grooming only in comparison with fasted controls. Compared to satiated animals, food deprived rats when injected ICV with anorexogenic doses of the peptides showed decreased resting and increased moving. Rats given SC injections of SV and U1 significantly decreased grooming in comparison with both food deprived and satiated controls, while increased resting only in comparison with fasted controls. CRF by the SC route did not affect the behaviour of the rat.

Amphibian Proteins↗
PubMed1984

[The presence of CEA in spinocellular carcinoma of the oral cavity].

Using an immunoperoxidase method the Authors have demonstrated carcinoembryonic antigen (CEA) in 4/7 patients with benign oral lesion and in 9/10 patients with oral cancer. All 4 oral leukoplakias were positive for CEA. The histologic presence of CEA in oral cancer was related mainly to the formation of well differentiated tissue. The anaplastic carcinoma was negative. These findings indicate that CEA is a product of differentiated cells and should not be considered exclusively an oncofetal antigen or a marker of undifferentiated cells.

Aged↗
PubMed1984

[Serum and salivary CEA in benign and malignant lesions of the oral cavity].

Serum carcinoembryonic antigen (CEA) and salivary CEA levels were determined for 18 patients with squamous oral carcinoma, 12 patients with oral leukoplakia, and 14 healthy volunteers. The determination of the CEA-serum levels has no diagnostic significance. Salivary CEA levels are not correlated with CEA-serum values, with cigarette consumption and clinical stage. Salivary CEA determination provides no additional information for the primary diagnosis. Serial determinations may have adjunctive value in monitoring oral cancer.

Adult↗
PubMed1984

Distribution and metabolism of dermorphin in rats.

Dermorphin distribution and metabolism were studied in rats injected with high doses of the peptide and with 125I-dermorphin, using RIA methods, HPLC extraction and -counting. Dermorphin rapidly disappeared from plasma (half-life: 1.3 min). In vivo and in vitro experiments demonstrated that the peptide was destroyed in liver and kidney. The highest percent (11%) of injected dermorphin has been found in the bile collected over 1 hour. HPLC analysis showed that bile contained also breakdown products (di, tri, and tetra N-terminal peptide fragments). Reported data suggested that intact dermorphin can be eliminated more slowly than breakdown products.

Animals↗
PubMed1984

Specific immunological stimulation induced by cryosurgery in patients with squamous-cell carcinoma of the oral cavity.

Following earlier personal studies indicating that cryosurgery stimulates several non-specific immunological parameters, mainly those of the cell-mediated component, in patients with squamous-cell carcinoma of the oral cavity, inhibition of leukocyte migration (evaluated by means of the LIF test) was investigated, using a heterologous squamous-cell tumour extract, before and 7 and 14 days after a single cryotherapy session in 14 patients (11 in stages I and II, 3 in stages III and IV). Increased inhibition was observed after 7 days in 8 subjects (57.2%)-72.7% in stage I-II patients. In two cases, reactivity appeared for the first time. In 7/8 cases, this increase persisted, though at lower levels, until the 14th day. The conclusion is drawn that cryosurgery can stimulate specific delayed hypersensitivity in stage I-II squamous-cell carcinoma of mouth.

Aged↗
PubMed1984

Dermorphin stimulates prolactin secretion in the rat.

The effect of dermorphin, a new opioid peptide originally isolated from amphibian skin, on the release of prolactin (Prl) was studied in vivo and in vitro. In vivo experiments: subcutaneous administrations of different doses of dermorphin ranging from 0.1 to 5 mg/kg body weight to normal male rats induce a statistically significant, dose-related increase in serum Prl levels. Pretreatment with the specific opioid antagonist, naloxone (2 mg/kg i.p.) completely prevents the rise in serum Prl, induced by 2 mg/kg of dermorphin. In normal male rats, the intraventricular injection of 0.25 micrograms/kg of dermorphin is not able to induce any significant changes in serum Prl levels 10 min after injection. Serum Prl levels show a significant enhancement 30 min after the administration of this dose of dermorphin, and return to control values at 60 min. On the contrary, 1 microgram/kg of dermorphin significantly elevates Prl concentrations 10 min after injection, leaving serum Prl levels unchanged 30 and 60 min after the administration. Naloxone (25 and 100 micrograms/kg) alone does not substantially modify serum Prl concentrations at any time interval considered. Treatment with either dose of naloxone performed together with either 0.25 or 1 microgram/kg of dermorphin completely counteracts the stimulatory effect of the peptide at all time intervals in which dermorphin was active when given alone. In orchidectomized (3 weeks) rats, the intraventricular administration of dermorphin at the dose of 0.25 micrograms/kg appears effective in enhancing Prl levels only 30 min after treatment. No statistically significant modifications are observed at 10 and 60 min with this dose.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Sauvagine induces release of adrenocorticotropin, beta-endorphin and corticosterone in rats.

The effect of sauvagine, a frog skin peptide, on ACTH, beta-endorphin and corticosterone secretion, was studied in rats. A subcutaneous injection of 5 micrograms kg-1 of sauvagine in rats produced a prompt increase in immunoreactive plasma concentration of ACTH and beta-endorphin, which reached a peak value 15-30 min after the peptide injection. The stimulatory action of sauvagine on ACTH and beta-endorphin secretion was dose related. Intensity and duration of corticosterone secretion, produced by sauvagine mediated ACTH release, was dose-dependent, the threshold dose being 0,5 microgram kg-1 s.c. Pretreatment of rats with dexamethasone-21-phosphate, prevented the corticosterone releasing effect of sauvagine. Sauvagine perfusion (2,1 nM/h) of biogel columns containing isolated and dispersed anterior pituitary cells induced a sharp increase of ACTH levels in the eluate. Considering the high corticotropin releasing potency of sauvagine and its chemical similarity to ovine CRF, it is interesting to hypothesize whether this peptide may represent, in lower vertebrates, an ancestral form of the mammalian hypothalamic releasing factor.

Adrenocorticotropic Hormone↗
PubMed1982

[Specific immunologic stimulation induced by cryosurgery of spinocellular tumors & of the oral cavity].

In previous works the Authors have shown that cryosurgical treatment of oral squamous cell cancer modifies numerous aspecific immunological parameters mostly concerning the cell-mediated component. In the present work the Authors have studied the leukocyte migration inhibition (LMI) response in vitro of peripheral blood leukocytes from patients affected by oral squamous cancer to oral tumor antigens using the leukocyte migration agarose test. The LMI was evaluated immediately before cryosurgical treatment of oral squamous cell carcinoma and 7 and 14 days after. The results suggest that cryosurgery is able to stimulate the specific cell-mediated response of patients affected by early stage carcinoma of oral cavity.

Aged↗
PubMed1982

[Secondary immunological response to cryosurgery in various stages of oral cavity neoplasms].

The authors have evaluated general immunocompetence after cryosurgical treatment of 33 patients affected by oral squamous carcinoma. Patients have been divided into two groups: 17 of them were classifiable in 1st and 2nd stage and 16 of them in 3rd and 4th stages. Serum immunoglobulin levels, C3 - C4, peripheral lymphocytes, E-rosette forming cells, lymphocyte response to PHA were analyzed before a single cryotreatment 7 and 14 days after. The results indicate that immunological parameters vary in a significant way and can be constantly observed in 1st and 2nd stages, while the 3rd and 4th stages undergo no variations. Cryosurgery in the 1st and 2nd stages is able to modify, in particular, the parameters concerning cell - mediate immunity, although the phenomenon seems transitory, showing itself most on the seventh day.

Adult↗