Biomedical subjects

F Massa

Publications and source records attributed to F Massa.

At least 19 recordsLinked to original sources

PubMed2006

CB1 and TRPV1 receptors mediate protective effects on colonic electrophysiological properties in mice.

CB1 and TRPV1 receptors modulate enteric neurotransmission and colonic inflammation. This study investigates early electrophysiological changes in distal colon of wild-type and receptor deficient mice after an inflammatory insult set by dinitrobenzene sulfonic acid (DNBS). Colitis was induced by DNBS in CB1(-/-) mice, TRPV1(-/-) mice, and their respective wild-type littermates. Electrophysiological properties consisting of membrane potentials and electrically induced inhibitory junction potentials (IJP) of circular smooth muscle cells were evaluated at different time points. Additionally a histological colitis severity score was evaluated in CB1(+/+) and CB1(-/-) mice 24 h after DNBS. Inflammation caused spontaneous atropine insensitive rhythmic action potentials in CB1(-/-) and TRPV1(-/-) mice but not in wild-type animals. This indicates that membrane stability is disturbed, which in turn indicates a lack of protective mechanisms. Focal electrical neuronal stimulation of the myenteric plexus induced IJP in the smooth muscle cells. Twenty-four hours after initiation of inflammation, the duration of the IJP is prolonged in all animals, indicating disturbances within neuromuscular interaction. In CB1(-/-) mice, it is interesting that the duration of IJP was significantly extended, as compared to CB1(+/+) mice pointing toward missing protective mechanisms in the CB1(-/-) mice. Inflammatory insults in the mouse colon induce reproducible changes in the electrophysiological properties and such changes correlate with duration of colitis. In mutants, these electrophysiological changes display different patterns, suggesting the lack of protective properties for neuromuscular interactions and membrane stability.

Action Potentials↗

PubMed2006

Endocannabinoids and the gastrointestinal tract.

In the past centuries, different preparations of marijuana have been used for the treatment of gastrointestinal (GI) disorders, such as GI pain, gastroenteritis and diarrhea. Delta9-tetrahydrocannabinol (THC; the active component of marijuana), as well as endogenous and synthetic cannabinoids, exert their biological functions on the gastrointestinal tract by activating two types of cannabinoid receptors, cannabinoid type 1 receptor (CB1 receptor) and cannabinoid type 2 receptor (CB2 receptor). While CB1 receptors are located in the enteric nervous system and in sensory terminals of vagal and spinal neurons and regulate neurotransmitter release, CB2 receptors are mostly distributed in the immune system, with a role presently still difficult to establish. Under pathophysiological conditions, the endocannabinoid system conveys protection to the GI tract, eg from inflammation and abnormally high gastric and enteric secretion. For such protective activities, the endocannabinoid system may represent a new promising therapeutic target against different GI disorders, including frankly inflammatory bowel diseases (eg, Crohn's disease), functional bowel diseases (eg, irritable bowel syndrome), and secretion- and motility-related disorders.

Animals↗

PubMed2005

Vanilloid receptor (TRPV1)-deficient mice show increased susceptibility to dinitrobenzene sulfonic acid induced colitis.

In the human colon, vanilloid receptor TRPV1 is overexpressed both in afferent nerve terminals and in epithelial cells during inflammation. In the past years, pharmacological experiments using TRPV1 agonists and antagonists revealed that TRPV1 receptors may play proinflammatory and protective roles in the gastrointestinal tract. Here, we applied a genetic approach to define the role of TRPV1 and analyzed the effects of dinitrobenzene sulfonic acid (DNBS)-induced colitis in TRPV1-deficient (TRPV1-/-) mice. Intrarectal infusion of DNBS induced increased inflammation in TRPV1-/- mice compared to wild-type littermates (TRPV1+/+) as evaluated by macroscopic scoring and myeloperoxidase assays. This finding indicates that TRPV1 receptors are required for the protection within sensory pathways that regulate the response following the initiation of colonic inflammation. Electrophysiological recordings from circular smooth-muscle cells, performed 8 and 24 h after DNBS treatment, revealed strong spontaneous oscillatory action potentials in TRPV1-/- but not in TRPV1+/+ colons, indicating an early TRPV1-mediated control of inflammation-induced irritation of smooth-muscle activities. These unexpected results suggest that TRPV1 receptors mediate endogenous protection against experimentally induced colonic inflammation.

Animals↗

PubMed2002

The use of nasal continuous positive airway pressure to treat obstructive sleep apnoea.

AIM: To review 66 children with obstructive sleep apnoea (OSA) for whom a trial of nasal continuous positive airway pressure (nCPAP) was proposed. METHODS: Baseline sleep studies were performed to assess OSA severity; a trial of nCPAP was performed where moderate to severe OSA, not relieved by adenotonsillectomy, was found. The nCPAP trial was considered either technically successful (ST), if the child accepted the mask for sufficient time to determine nCPAP efficacy, or a technical failure (FT) if otherwise. Patients with an initial FT were offered a period of home acclimatisation to familiarise them with wearing the mask during sleep. ST patients in whom nCPAP was effective were established on long term therapy. RESULTS: Nasal CPAP trials were successful (ST) in 49/66 (74%) patients. Nasal CPAP efficacy could not be determined in the remaining 17 FT patients (26%), generally because of their poor nCPAP tolerance. These patients were subsequently considered for other treatment. A total of 42/49 (86%) ST patients were established on long term nCPAP therapy, 2/49 (4%) derived no benefit from nCPAP, while 5/49 (10%) refused long term nCPAP therapy. Of patients on long term nCPAP, the most frequently reported side effects were skin irritation and nasal dryness; however, these were not serious enough to require any patients to discontinue therapy. A period of home acclimatisation was found to be effective in increasing nCPAP acceptance, with 26% of FT children being subsequently successfully reassessed for nCPAP. CONCLUSION: The use of nCPAP was feasible in a significant proportion of a paediatric OSA population. Failure was usually because of the child's intolerance of the nCPAP equipment. Nasal CPAP was an effective treatment in the majority of patients where it could be assessed, and was adopted as a long term therapy in most cases. We have successfully used nCPAP to treat OSA across a wide range of ages. Motivated parents and skilled support staff have proved essential for the success of nCPAP in a paediatric setting.

Adolescent↗

PubMed2001

Increase in expression of the GABA(A) receptor alpha(4) subunit gene induced by withdrawal of, but not by long-term treatment with, benzodiazepine full or partial agonists.

The effects of long-term exposure to, and subsequent withdrawal of, diazepam or imidazenil (full and partial agonists of the benzodiazepine receptor, respectively) on the abundance of GABA(A) receptor subunit mRNAs and peptides were investigated in rat cerebellar granule cells in culture. Exposure of cells to 10 microM diazepam for 5 days significantly reduced the amounts of alpha(1) and gamma(2) subunit mRNAs, and had no effect on the amount of alpha(4) mRNA. These effects were accompanied by a decrease in the levels of alpha(1) and gamma(2) protein and by a reduction in the efficacy of diazepam with regard to potentiation of GABA-evoked Cl- current. Similar long-term treatment with 10 microM imidazenil significantly reduced the abundance of only the gamma(2)S subunit mRNA and had no effect on GABA(A) receptor function. Withdrawal of diazepam or imidazenil induced a marked increase in the amount of alpha(4) mRNA; withdrawal of imidazenil also reduced the amounts of alpha(1) and gamma(2) mRNAs. In addition, withdrawal of diazepam or imidazenil was associated with a reduced ability of diazepam to potentiate GABA action. These data give new insights into the different molecular events related to GABA(A) receptor gene expression and function produced by chronic treatment and withdrawal of benzodiazepines with full or partial agonist properties.

Animals↗

PubMed2001

Exhaled nitric oxide in asthmatic and non-asthmatic children: influence of type of allergen sensitization and exposure to tobacco smoke.

Asthmatic bronchial inflammation is associated with increased nitric oxide concentrations in exhaled air (eNO). Recent data suggest that this effect arises from atopy. Our aim in this study was to find out whether atopy and sensitization to particular allergens influences eNO levels. A total of 213 subjects (41 asthmatics and 172 controls) (96 boys and 117 girls, 7.3-14 years of age) were studied. Parents completed a questionnaire that sought information on their children's respiratory symptoms and exposure to tobacco smoke. Subjects underwent skin-prick tests for the following common allergens: Dermatophagoides pteronyssinus (Dpt), cat fur, Aspergillus fumigatus, Alternaria tenuis, mixed grass, mixed tree pollen, Parietaria officinalis, egg, and cow's milk. eNO was collected in 1-l mylar bags (exhaled pressure 10 cmH2O, flow 58 ml/s) and analyzed by using chemiluminescence. Atopic and non-atopic children without a history of chronic respiratory symptoms had a similar geometric mean eNO (atopics, n = 28, 11.2 p.p.b.; non-atopics, n = 96, 10.0 p.p.b.; mean ratio 1.1, 95% confidence interval [CI]: 0.7-1.6). Conversely, atopic asthmatic subjects had significantly higher eNO values than non-atopic asthmatic subjects (atopics, n = 25, 24.8 p.p.b.; non-atopics, n = 16, 11.4 p.p.b.; mean ratio 2.2, 95% CI: 1.2-3.9, p= 0.000). In children with rhinitis alone (n = 15) and those with lower respiratory symptoms other than asthma (n = 33), eNO increased slightly, but not significantly, with atopy. eNO levels correlated significantly with Dpt wheal size (r = 0.51) as well with the wheal size for cat, mixed grass, and Parietaria officinalis (r = 0.30-0.29), and with the sum of all wheals (r = 0.47) (p= 0.000). Subjects sensitized only for Dpt (but not those subjects sensitized only for grass pollen or other allergens) showed significantly higher eNO levels than non-atopic subjects (16.4 p.p.b. vs. 10.2 p.p.b., mean ratio 1.6, 95% CI: 1.1-2.3, p= 0.002). In asthmatic subjects, Dpt sensitization markedly increased eNO levels (Dpt-sensitized subjects: 28.0 p.p.b.; Dpt-unsensitized subjects: 12.2 p.p.b.; mean ratio 2.3, 95% CI: 1.5-3.5, p= 0.000). Non-asthmatic Dpt-sensitized subjects also had significantly higher eNO values than non-asthmatic, non-Dpt-sensitized subjects (14.2 p.p.b. vs. 10.1 p.p.b.; mean ratio 1.4, 95% CI: 1.1-1.9, p= 0.008). No difference was found between eNO levels in asthmatic subjects and control subjects exposed or unexposed to tobacco smoke. In conclusion, eNO concentrations are high in atopic asthmatic children and particularly high in atopic asthmatics who are sensitized to house-dust mite allergen.

Allergens↗

PubMed2000

Chronology of the appearance of beta, A, and alpha mitochondria-rich cells in the gill epithelium during ontogenesis of the brown trout (Salmo trutta).

Three types of mitochondria-rich (MR) cells, the alpha, beta, and accessory cells, are observed in the gill epithelium of juvenile and adult freshwater teleosts. In addition to numerous mitochondria, their cytoplasm contains a network of membranous tubules, the tubular system, connected to the laterobasal plasma membrane. Because they are believed to play a role in ionic regulation, it is of interest to examine the order of appearance and the ultrastructural characteristics of such cells during the embryogenesis and larval life of the brown trout. Gills of embryos and fry maintained in freshwater were thus removed at different stages and prepared for transmission and scanning electron microscopic examination. One week before hatching, cells resembling the beta cells of juvenile and adult teleosts appeared first among the epithelial cells located at the base of the filaments in the gills of the brown trout larva. In addition to their tubular system, they contained numerous and large apical structures seemingly originating from the Golgi apparatus. At approximately hatching time, small pear-shaped cells were seen to be closely apposed to the lateral side of the beta cells; they were usually devoid of apical structures and were considered to be accessory cells. After yolk sac resorption, additional cells, the alpha cells, were present along the lamellae. In contrast to the beta cells, they only exhibited poorly developed apical structures. The possible role of these three types of MR cells in osmoregulation during fish development is discussed.

Animals↗

PubMed2000

Complexation of zolpidem with 2-hydroxypropyl-beta-, methyl-beta-, and 2-hydroxypropyl-gamma-cyclodextrin: effect on aqueous solubility, dissolution rate, and ataxic activity in rat.

The effect of some chemically modified cyclodextrins [namely, 2-hydroxypropyl-beta-, methyl-beta-, and 2-hydroxypropyl-gamma-cyclodextrin (HP-beta-CD, Me-beta-CD, and HP-gamma-CD, respectively)] on the aqueous solubility and dissolution rate of the hypnotic agent Zolpidem (ZP) was investigated. Solid complexes were prepared by freeze drying and characterized by infrared spectroscopy, X-ray powder diffraction, and differential scanning calorimetry. The solubility and dissolution rate of the drug were significantly improved by complexation with HP-beta-CD or Me-beta-CD. The structure of the inclusion complex ZP-HP-beta-CD in CH(3)COOD/D(2)O was investigated by (1)H and (13)C NMR spectroscopy, including NOE measurements. These measurements revealing a weak interaction between the tolyl moiety of the guest molecule and the HP-beta-CD cavity. The ataxic activity in rat was also investigated and it was found that ZP-HP-beta-CD and ZP-Me-beta-CD complexes showed almost 2-fold longer ataxic induction times than controls.

2-Hydroxypropyl-beta-cyclodextrin↗

PubMed2000

Effects of sleep stage and age on short-term heart rate variability during sleep in healthy infants and children.

STUDY DESIGN: Power spectrum analysis of heart rate variability (HRV) is a noninvasive technique that provides a quantitative assessment of cardiovascular neural control. Using this technique, we studied the autonomic nervous system changes induced by sleep in 14 healthy subjects: 7 infants (mean age, 9.40 +/- 2.32 months) and 7 children (mean age, 8.93 +/- 0.65 years) during a standard all-night polysomnographic recording. Our primary aim was to assess the effect of sleep stage and age on short-term HRV during sleep in healthy infants and children. Power spectral density was estimated by autoregressive modeling over 250 consecutive R-R intervals. In this study, we mainly considered two spectral components: the high-frequency (HF) component (0.15 to 0.40 Hz), which reflects parasympathetic cardiovascular modulation; and the low-frequency (LF) component (0.04 to 0.15 Hz), generally considered due to both parasympathetic and sympathetic modulation. RESULTS: Heart rate was higher (p < 0.01 in all sleep stages) and total power lower (p < 0. 02) in infants than in children. HF power was higher in children than in infants (p < 0.05). In infants and children, the ratio between LF and HF powers changed with the various sleep stages (p < 0.02 in infants; p < 0.01 in children): it decreased during deep sleep and increased during rapid eye movement sleep. However, it was invariably lower in children than in infants. CONCLUSION: These findings show that the sleep stage and age both significantly influence short-term HRV during sleep in healthy infants and children. Hence, to provide unbiased results, HRV studies investigating the effects of age on autonomic nervous system activity should segment sleep into the five stages. In addition, despite a relatively small study sample, our data confirm greater parasympathetic control during sleep in children than in infants.

Autonomic Nervous System↗

PubMed2000

Allopregnanolone synthesis in cerebellar granule cells: roles in regulation of GABA(A) receptor expression and function during progesterone treatment and withdrawal.

Rat cerebellar granule cells were cultured for 5 days with progesterone, resulting in the conversion of progesterone to allopregnanolone, a potent and efficacious modulator of gamma-aminobutyric acid (GABA) type-A receptors, as well as in decreases in the abundance of GABA(A) receptor alpha(1), alpha(3), alpha(5), and gamma(2) subunit mRNAs. These effects were accompanied by decreases in the efficacies of diazepam and the beta-carboline DMCM with regard to modulation of GABA-evoked Cl(-) currents. Withdrawal from such progesterone treatment resulted in a rapid and selective increase in the abundance of the GABA(A) alpha(4) subunit mRNA that was associated with a restoration of receptor sensitivity to the negative modulatory action of DMCM, a positive receptor response to flumazenil, and continued reduced responsiveness of receptors to diazepam. Prevention of allopregnanolone synthesis by the 5alpha-reductase inhibitor finasteride also prevented the changes in both GABA(A) receptor gene expression and receptor function elicited by progesterone treatment and withdrawal.

Animals↗

PubMed1999

Molecular and neurochemical evaluation of the effects of etizolam on GABAA receptors under normal and stress conditions.

The thienobenzodiazepine derivative etizolam (CAS 40054-69-1, 6-(o-chlorophenyl)-8-ethyl-1-methyl-4H-s-triazolo-(3,4-c)thienol(1 ,4) diazepine) is a potent anxiolytic with a pharmacological profile similar to that of classical benzodiazepines. In order to rationalize the therapeutic use of etizolam, its pharmacodynamics properties on GABAA receptors were investigated by a comparative study with other ligands on human recombinant GABAA as well as rat brain native receptors. Etizolam inhibited in a concentration-dependent manner [3H]flunitrazepam (CAS 1622-62-4) binding to rat cortical membranes, with an affinity of 4.5 nmol/l greater than that of alprazolam (CAS 28981-97-7) (7.9 nmol/l). Ethizolam enhanced GABA-induced Cl- currents in oocytes expressing human cloned GABAA receptors. With alpha 1 beta 2 gamma 2S subunit combination, etizolam produced a 73% increase in GABA-induced currents with an EC50 of 92 nmol/l. At the same receptor type, alprazolam showed a higher degree of potentiation and potency (98%, EC50 56 nmol/l). At alpha 2 beta 2 gamma 2S or alpha 3 beta 2 gamma 2S subunit constructs, the effects of etizolam were similar to those of alprazolam. Flumazenil (CAS 78755-81-4) completely blocked both etizolam and alprazolam effects on GABA-induced currents. Etizolam, administered i.p., was uneffective in changing ex vivo t-[35S]butylbicyclophosphorothionate ([35S]-TBPS) binding to rat cerebral cortex, whereas alprazolam and abecarnil (CAS 111841-85-1) significantly reduced this parameter. However, etizolam similarly to abecarnil and alprazolam, antagonized isoniazid-induced increase (61%) in [35S]-TBPS binding to rat cortical membranes. Further, etizolam inhibited in a dose-dependent manner basal acetylcholine release from both hippocampus and prefrontal cortex, and reversed foot-shock-induced increase of basal acetylcholine release to a control level. Altogether, these results suggest that etizolam may have a reduced intrinsic activity, at least at specific subpopulations of GABAA receptors. This property, together with the pharmacokinetic indication of a short-acting drug, may characterize etizolam as a ligand endowed with less side-effects typical of full agonits such as diazepam (CAS 439-14-5) and alprazolam. Finally, given its marked efficacy under conditions of GABAergic deficit, etizolam may represent a possible drug of choice with reduced liability to produce tolerance and dependence after long-term treatment of anxiety and stress syndromes.

Acetylcholine↗

PubMed1997

[Analysis of the results of 137 subclinical breast lesions excisions. Value of ultrasonography in the early diagnosis of breast cancer].

OBJECTIVE: Ultrasonography is invaluable for evaluation of palpable masses and masses detected by mammography. Ultrasound has no proved role in breast screening. Between 1991 and 1994, we included ultrasonography routinely in our screening mammography prescription, not only for evaluation of mass detected by mammography but also in radiographically dense, non-radiolucent breast. One hundred and thirty-seven suspicious but non palpable breast lesions were detected. We analyzed the results of the surgical excision biopsies of these lesions and evaluated the contribution of ultrasonography combined with mammography to detect occult breast cancers. MATERIAL AND METHODS: From 1991 to 1994, our institution performed 8,489 individual screening mammographies. All women underwent physical examination before mammography. Women with abnormal clinical breast examination are not included in the study. Ultrasonography was routinely performed for characterization of a mass detected by mammography and also in normal breast with dense, non-radiolucent tissue. One hundred and thirty-seven suspected breast lesions were removed after immediate preoperative stereotaxic or US-guided needle localization. Screened women were aged 29-72 years (mean 51 years). 48% of all screened women were aged 50 years and older. RESULTS: The histopathologic findings were as follow: invasive ductal carcinoma (IDC) 40 cases (59%), invasive lobular carcinoma (ILC) 7 cases (10%), ductal carcinoma in situ 21 cases (31%). Infracllnic cancer was identified by mammography alone in 45% of cases, by mammography and sonography in 43.2% of cases, by sonography alone in 11.8% of cases. About 31% of infraclinic cancer occur prior to the age of 50 (age range: 29-72, mean: 54). Cancer less than 10 mm in diameter were found in 57.5% of lesions. Axillary dissection was performed in 46 cases of invasive cancer, with a incidence of axillary node metastases of 15%. CONCLUSION: The combination of mammography and ultrasonography is effective to detect a greater number of occult breast cancers and we recommend ultrasonography not only for evaluation of a mass detected by mammography but also in radiographically dense non-radiolucent breast lesions.

Adult↗

PubMed1989

[Treatment of amyloidosis with dimethyl sulfoxide (DMSO)].

In this study we have investigated the role of oral dimethylsulfoxide (DMSO) therapy in 2 patients with primary amyloidosis (AL) and in 2 patients with secondary amyloidosis (AA) to long-standing rheumatoid arthritis. DMSO treatment produced no beneficial effects in the patients with idiopathic amyloidosis. Instead the patients with secondary amyloidosis experienced a subjective improvement, a decrease of inflammatory activity of the rheumatoid arthritis and an unequivocal improvement of renal function following 3-6 months of DMSO therapy. No serious side effects of DMSO were observed except for unpleasant breath odour. We conclude that a treatment with oral DMSO may prolong life of patients with secondary amyloidosis.

Administration, Oral↗

PubMed1987

Prevention of surgically induced miosis by diclofenac eye drops.

In this investigation, a rabbit model was used to study the effectiveness of topical diclofenac sodium in the prevention of miosis induced by manipulation of the ocular structures. In untreated rabbit eyes, paracentesis of the anterior chamber induced a 25% narrowing of the pupil. In atropine-treated rabbit eyes, the absolute pupil diameters were larger, but the pupil still contracted, resulting in a postoperative diameter of 6.5 mm. Pretreatment with diclofenac 0.1% eye drops effectively inhibited paracentesis-induced miosis; the postoperative pupil narrowing amounted to only 9% of the original diameter in both untreated and atropine-treated eyes. With a combined topical application of atropine and diclofenac, the mean pupil diameters after paracentesis were as large as 8.7 mm. Diclofenac seems to be a promising drug for the maintenance of mydriasis during eye surgery.

Animals↗

PubMed1983

Intraocular-pressure-lowering effect of low-dosage combination of guanethidine and terbutaline in rabbit.

A low dosage combination of terbutaline plus guanethidine was applied topically to the eyes of rabbits with experimentally induced ocular hypertension, markedly lowering intraocular pressure. The effect of this combination is markedly greater than that produced separately by the two components at corresponding dosages and seems to be due to a true synergistic phenomenon. The low-dosage combination of terbutaline and guanethidine appears to be well tolerated, very potent and effective as a topical ocular hypotensive agent.

Animals↗

PubMed1982

Intraocular pressure in myopic anisometropia.

The authors studied the intraocular pressure, scleral rigidity and outflow facility of 137 anisometropic subjects with unilateral high myopia. The contralateral eyes were emmetropic, hyperopic or slightly myopic (less than 5 diopters). No difference was found between the intraocular pressure on the two sides. The scleral rigidity was lower and the outflow facility higher on the myopic side. It is concluded that high myopia is not, in itself, a cause of ocular hypertension, nor is caused by it.

Adolescent↗

PubMed1982

Effects of dapiprazole on pupillary size and intraocular pressure in rabbits.

The effects of 3-[2-[4-(2-methylphenyl)-1- piperazinyl]ethyl]-5,6,7,8-tetrahydro-1,2,4-triazolo[4,3-a]pyridine HCl (dapiprazole), a new drug with alpha-adrenergic blocking properties, on pupillary diameter and intraocular pressure have been studied in rabbits. Following i.v. administration, a reduction of intraocular pressure is observed at doses devoid of activity on pupillary diameter. Following topical application, a miotic and ocular hypertensive action was observed at the same doses; the hypotensive action is produced in both normal rabbits and in rabbits with water load- or corticosteroid-induced ocular hypertension. Contact lenses increase the duration of effects of dapiprazole. These results suggest a potential interest of dapiprazole in glaucoma, with particular reference to the topical treatment of angle-closure glaucoma.

Administration, Topical↗

PubMed1981

Ocular hypotensive action of labetalol in rabbit and human eyes.

The ocular hypotensive action of labetalol, a drug endowed with alpha- and beta-adrenergic receptor-blocking properties, was studied in both rabbit and human eyes. In the rabbit, using two different models of experimentally induced ocular hypertension, an impressive decrease of IOP was seen after topical administration of the drug. In this species labetalol was found to be at least as effective as timolol and more active than pilocarpine or propranolol. In human eyes suffering from glaucoma, however, its effectiveness was much less evident and clearly inferior to that of timolol.

Animals↗