Gastrointestinal parasites in captive and free-living wild birds in Goiania Zoo.

Helminths are endoparasites that infect a variety of bird species. Endoparasite infections can cause severe diseases, including kill captive avian hosts and represents a problem to maintenance and conservation. The eggs and larval forms of these parasites are usually eliminated in the host feces. The main interest of this study is to report the occurrence of eggs and oocysts in feces from captive wild birds in Goiânia Zoo and free-living birds in its surroundings. The fecal samples were subjected to parasitological examination to identify the presence of helminths and to classify their eggs based on morphological characteristics. Eggs of nematode parasites (Positive/N) were identified as Ascaridia spp. in Brotogeris chiriri (2/2), Dromaius novaehollandiae (1/1) and Rhea americana (2/2); Ascarididae in Pavo cristatus nigripensis (1/1); Capillaria spp. in Ara chloropterus (1/1) and Penelope jacucaca (1/1); Capillaria plagiaticia in Anodorhynchus hyacinthinus (1/2) and Ara spp. (2/2); Capillaria venusta in Rhamphastus tucanus (1/2); and unidentified nematode eggs from Amazona amazonica (2/2). Eimeria spp. oocyst was founded in feces from A. hyacinthinus (1/2). Considering free-living birds, Diphyllobothrium spp. eggs were founded in Ardea alba (2/2) and Nycticorax nycticorax (2/3). Co-infection of Eustrongylides spp. was founded in A. alba (1/2). This is the first occurrence of: Ascaridia spp. parasitizing B. chiriri; and C. venusta parasitizing R. tucanus. In conclusion, the helminth eggs found in the abovementioned host bird species are consistent with those reported in the literature, and treatment and control protocols were based on their identification.

Gastrointestinal parasites in captive and free-living wild birds in Goiania Zoo / Parasitas gastrointestinais em aves silvestres em cativeiro e de vida livre no Zoológico de Goiânia

Helminths are endoparasites that infect a variety of bird species. Endoparasite infections can cause severe diseases, including kill captive avian hosts and represents a problem to maintenance and conservation. The eggs and larval forms of these parasites are usually eliminated in the host feces. The main interest of this study is to report the occurrence of eggs and oocysts in feces from captive wild birds in Goiânia Zoo and free-living birds in its surroundings. The fecal samples were subjected to parasitological examination to identify the presence of helminths and to classify their eggs based on morphological characteristics. Eggs of nematode parasites (Positive/N) were identified as Ascaridia spp. in Brotogeris chiriri (2/2), Dromaius novaehollandiae (1/1) and Rhea americana (2/2); Ascarididae in Pavo cristatus nigripensis (1/1); Capillaria spp. in Ara chloropterus (1/1) and Penelope jacucaca (1/1); Capillaria plagiaticia in Anodorhynchus hyacinthinus (1/2) and Ara spp. (2/2); Capillaria venusta in Rhamphastus tucanus (1/2); and unidentified nematode eggs from Amazona amazonica (2/2). Eimeria spp. oocyst was founded in feces from A. hyacinthinus (1/2). Considering free-living birds, Diphyllobothrium spp. eggs were founded in Ardea alba (2/2) and Nycticorax nycticorax (2/3). Co-infection of Eustrongylides spp. was founded in A. alba (1/2). This is the first occurrence of: Ascaridia spp. parasitizing B. chiriri; and C. venusta parasitizing R. tucanus. In conclusion, the helminth eggs found in the abovementioned host bird species are consistent with those reported in the literature, and treatment and control protocols were based on their identification.

Helmintos são endoparasitas que infectam uma variedade de espécies de aves. As infecções por endoparasitas podem causar doenças graves, podendo matar aves em cativeiro e representam um problema de manutenção e conservação. Os ovos e as formas larvais desses parasitas são geralmente eliminados nas fezes do hospedeiro. O principal objetivo deste estudo é relatar a ocorrência de ovos e oocistos em fezes de aves silvestres em cativeiro no Zoológico de Goiânia e em aves de vida livre em seu entorno. As amostras fecais foram submetidas a exame parasitológico para identificação da presença de helmintos e classificação dos ovos com base nas características morfológicas. Ovos de nematóides (Positivo/N) foram identificados como Ascaridia spp. em Brotogeris chiriri (2/2), Dromaius novaehollandiae (1/1) e Rhea americana (2/2); Ascarididae em Pavo cristatus nigripensis (1/1); Capillaria spp. em Ara chloropterus (1/1) e Penelope jacucaca (1/1); Capillaria plagiaticia em Anodorhynchus hyacinthinus (1/2) e Ara spp. (2/2); Capillaria venusta em Rhamphastus tucanus (1/2); e ovos de nematóide não identificado de Amazona amazonica (2/2). Oocistos de Eimeria spp. foram encontrados nas fezes de A. hyacinthinus (1/2). Considerando pássaros de vida livre, ovos de Diphyllobothrium spp. foram encontrados em Ardea alba (2/2) e Nycticorax nycticorax (2/3). Coinfecção de Eustrongylides spp. foi encontradada em A. alba (1/2). Esta é a primeira ocorrência de: Ascaridia spp. parasitando B. chiriri; e C. venusta parasitando R. tucanus. Em conclusão, os ovos de helmintos encontrados nas espécies de aves hospedeiras acima mencionadas são consistentes com os relatados na literatura, e os protocolos de tratamento e controle foram baseados em sua identificação.

Gastrointestinal parasites in captive and free-living wild birds in Goiania Zoo

Abstract Helminths are endoparasites that infect a variety of bird species. Endoparasite infections can cause severe diseases, including kill captive avian hosts and represents a problem to maintenance and conservation. The eggs and larval forms of these parasites are usually eliminated in the host feces. The main interest of this study is to report the occurrence of eggs and oocysts in feces from captive wild birds in Goiânia Zoo and free-living birds in its surroundings. The fecal samples were subjected to parasitological examination to identify the presence of helminths and to classify their eggs based on morphological characteristics. Eggs of nematode parasites (Positive/N) were identified as Ascaridia spp. in Brotogeris chiriri (2/2), Dromaius novaehollandiae (1/1) and Rhea americana (2/2); Ascarididae in Pavo cristatus nigripensis (1/1); Capillaria spp. in Ara chloropterus (1/1) and Penelope jacucaca (1/1); Capillaria plagiaticia in Anodorhynchus hyacinthinus (1/2) and Ara spp. (2/2); Capillaria venusta in Rhamphastus tucanus (1/2); and unidentified nematode eggs from Amazona amazonica (2/2). Eimeria spp. oocyst was founded in feces from A. hyacinthinus (1/2). Considering free-living birds, Diphyllobothrium spp. eggs were founded in Ardea alba (2/2) and Nycticorax nycticorax (2/3). Co-infection of Eustrongylides spp. was founded in A. alba (1/2). This is the first occurrence of: Ascaridia spp. parasitizing B. chiriri; and C. venusta parasitizing R. tucanus. In conclusion, the helminth eggs found in the abovementioned host bird species are consistent with those reported in the literature, and treatment and control protocols were based on their identification.

Resumo Helmintos são endoparasitas que infectam uma variedade de espécies de aves. As infecções por endoparasitas podem causar doenças graves, podendo matar aves em cativeiro e representam um problema de manutenção e conservação. Os ovos e as formas larvais desses parasitas são geralmente eliminados nas fezes do hospedeiro. O principal objetivo deste estudo é relatar a ocorrência de ovos e oocistos em fezes de aves silvestres em cativeiro no Zoológico de Goiânia e em aves de vida livre em seu entorno. As amostras fecais foram submetidas a exame parasitológico para identificação da presença de helmintos e classificação dos ovos com base nas características morfológicas. Ovos de nematóides (Positivo/N) foram identificados como Ascaridia spp. em Brotogeris chiriri (2/2), Dromaius novaehollandiae (1/1) e Rhea americana (2/2); Ascarididae em Pavo cristatus nigripensis (1/1); Capillaria spp. em Ara chloropterus (1/1) e Penelope jacucaca (1/1); Capillaria plagiaticia em Anodorhynchus hyacinthinus (1/2) e Ara spp. (2/2); Capillaria venusta em Rhamphastus tucanus (1/2); e ovos de nematóide não identificado de Amazona amazonica (2/2). Oocistos de Eimeria spp. foram encontrados nas fezes de A. hyacinthinus (1/2). Considerando pássaros de vida livre, ovos de Diphyllobothrium spp. foram encontrados em Ardea alba (2/2) e Nycticorax nycticorax (2/3). Coinfecção de Eustrongylides spp. foi encontradada em A. alba (1/2). Esta é a primeira ocorrência de: Ascaridia spp. parasitando B. chiriri; e C. venusta parasitando R. tucanus. Em conclusão, os ovos de helmintos encontrados nas espécies de aves hospedeiras acima mencionadas são consistentes com os relatados na literatura, e os protocolos de tratamento e controle foram baseados em sua identificação.

Gastrointestinal parasites in captive and free-living wild birds in Goiania Zoo / Parasitas gastrointestinais em aves silvestres em cativeiro e de vida livre no Zoológico de Goiânia

Helminths are endoparasites that infect a variety of bird species. Endoparasite infections can cause severe diseases, including kill captive avian hosts and represents a problem to maintenance and conservation. The eggs and larval forms of these parasites are usually eliminated in the host feces. The main interest of this study is to report the occurrence of eggs and oocysts in feces from captive wild birds in Goiânia Zoo and free-living birds in its surroundings. The fecal samples were subjected to parasitological examination to identify the presence of helminths and to classify their eggs based on morphological characteristics. Eggs of nematode parasites (Positive/N) were identified as Ascaridia spp. in Brotogeris chiriri (2/2), Dromaius novaehollandiae (1/1) and Rhea americana (2/2); Ascarididae in Pavo cristatus nigripensis (1/1); Capillaria spp. in Ara chloropterus (1/1) and Penelope jacucaca (1/1); Capillaria plagiaticia in Anodorhynchus hyacinthinus (1/2) and Ara spp. (2/2); Capillaria venusta in Rhamphastus tucanus (1/2); and unidentified nematode eggs from Amazona amazonica (2/2). Eimeria spp. oocyst was founded in feces from A. hyacinthinus (1/2). Considering free-living birds, Diphyllobothrium spp. eggs were founded in Ardea alba (2/2) and Nycticorax nycticorax (2/3). Co-infection of Eustrongylides spp. was founded in A. alba (1/2). This is the first occurrence of: Ascaridia spp. parasitizing B. chiriri; and C. venusta parasitizing R. tucanus. In conclusion, the helminth eggs found in the abovementioned host bird species are consistent with those reported in the literature, and treatment and control protocols were based on their identification.

Helmintos são endoparasitas que infectam uma variedade de espécies de aves. As infecções por endoparasitas podem causar doenças graves, podendo matar aves em cativeiro e representam um problema de manutenção e conservação. Os ovos e as formas larvais desses parasitas são geralmente eliminados nas fezes do hospedeiro. O principal objetivo deste estudo é relatar a ocorrência de ovos e oocistos em fezes de aves silvestres em cativeiro no Zoológico de Goiânia e em aves de vida livre em seu entorno. As amostras fecais foram submetidas a exame parasitológico para identificação da presença de helmintos e classificação dos ovos com base nas características morfológicas. Ovos de nematóides (Positivo/N) foram identificados como Ascaridia spp. em Brotogeris chiriri (2/2), Dromaius novaehollandiae (1/1) e Rhea americana (2/2); Ascarididae em Pavo cristatus nigripensis (1/1); Capillaria spp. em Ara chloropterus (1/1) e Penelope jacucaca (1/1); Capillaria plagiaticia em Anodorhynchus hyacinthinus (1/2) e Ara spp. (2/2); Capillaria venusta em Rhamphastus tucanus (1/2); e ovos de nematóide não identificado de Amazona amazonica (2/2). Oocistos de Eimeria spp. foram encontrados nas fezes de A. hyacinthinus (1/2). Considerando pássaros de vida livre, ovos de Diphyllobothrium spp. foram encontrados em Ardea alba (2/2) e Nycticorax nycticorax (2/3). Coinfecção de Eustrongylides spp. foi encontradada em A. alba (1/2). Esta é a primeira ocorrência de: Ascaridia spp. parasitando B. chiriri; e C. venusta parasitando R. tucanus. Em conclusão, os ovos de helmintos encontrados nas espécies de aves hospedeiras acima mencionadas são consistentes com os relatados na literatura, e os protocolos de tratamento e controle foram baseados em sua identificação.

Changes in mucosal fatty acid profile in inflammatorybowel disease and in experimental colitis: a common response to bowel inflammation.

BACKGROUND AND AIMS: Plasma polyunsaturated fatty acid profile in patients with inflammatory bowel disease is abnormal. We aimed to assess the mucosal fatty acid pattern in patients with ulcerative colitis and Crohn's disease, and in rats with trinitrobenzene-sulfonic acid (TNB) induced colitis. METHODS: Fatty acids were measured in colonic mucosa of patients with ulcerative colitis (n = 30), Crohn's disease (n = 21), and healthy controls (n = 13). Likewise, they were assessed in the colonic mucosa of rats with TNB- and sham-colitis. RESULTS: There was an increase of the end-products (C22:5n3, C22:6n3, C20:4n6, C22:5n6) and a decrease of the precursors (C18:3n3, C18:2n6) of both n3 and n6 polyunsaturated fatty acids in the mucosa of active ulcerative colitis and TNB-colitis. Also, high values of saturated (C16:0, C18:0) and low values of monounsaturated fatty acids (C18:1n9) were observed. Furthermore, the mucosa of active Crohn's disease showed substantial changes in saturated, monounsaturated and essential fatty acids, but not in polyunsaturated fatty acids. Mucosa of patients with inactive disease showed intermediate fatty acid values between the mucosa of active patients and healthy controls. CONCLUSIONS: Colonic inflammation causes a characteristic modification of the mucosal fatty acid profile which appears to be common to different aetiologies and seems to be related to the degree of inflammation.

Effect of L-arginine on the course of experimental colitis.

BACKGROUND AND AIMS: L-Arg is the substrate for nitric oxide, and also for L-ornithine which, in turn, is the precursor for the synthesis of collagen and polyamines. By these different metabolic pathways, L-Arg is involved in the mechanisms of inflammation, tissue repair and fibrosis. Thus, the aim of this study was to assess the effect of both different amounts of L-Arg supplementation and L-Arg-free diets upon colonic inflammatory damage and fibrosis in experimental colitis. METHODS: Sprague-Dawley rats with trinitrobenzene sulphonic acid (TNBS)-induced colitis received increasing doses of L-Arg (30, 100, 500 mg/day), or D-Arg (500 mg/day). In a second experiment, two L-Arg-free diets (one supplemented with L-Gly) were compared to a L-Arg diet. Nitrite/nitrate release in the lumen of the colon and colonic damage were evaluated. In the first experiment, tissue collagen levels and colonic mucosal proliferation were also assessed. RESULTS: In the acute phase of colitis, intracolonic nitrite/nitrate levels were significantly higher in the 100 and 500 mg supplemented L-Arg groups than in D-Arg group. However, only rats treated with 500 mg of L-Arg showed moderately higher inflammatory and fibrosis colonic scores than the D-Arg treated rats. There was no significant influence of L-Arg-free diets on the course of TNBS-induced colitis. However, L-Arg diet accelerated weight gain both pre- and post-TNBS. CONCLUSIONS: These results suggest that normal amounts of L-Arg in the diet are not harmful, whereas both absence of L-Arg or supplementation with high doses of this amino acid may be deleterious. In the former this might be due to a decrease of nitrogen retention in injured rats, whereas in the latter it may result from both nitric oxide-mediated tissue damage and collagen deposition.

[Ligation of the hilar arteries in hemorrhages due to traumatic rupture of the liver]. / La legatura delle arterie ilari nelle emorragie da rottura traumatica del fegato.

The paper reports two cases of severe hematoperitoneum due to the traumatic rupture, or so-called explosion, of the liver. During surgery one of these cases underwent ligature of the right and left hepatic arteries, while the other only underwent right hepatic arterial ligature. Selective arteriography at varying intervals after surgery showed that vascular occlusion had taken place together with the creation of an adequate compensation circle. Both patients now lead absolutely normal lives, respectively five and two years after surgery. This technique of hemostasis, which is reserved for use in cases of otherwise unresolvable hepatic hemorrhage, although still rarely used, should form part of every surgeon's general training since it might prove unexpectedly essential.

Insulin-like growth factor I improves intestinal barrier function in cirrhotic rats.

BACKGROUND AND AIMS: In liver cirrhosis, disruption of the intestinal barrier facilitates bacterial translocation and spontaneous bacterial peritonitis. Insulin-like growth factor I (IGF-I) is an anabolic hormone synthesised by hepatocytes that displays hepatoprotective activities and trophic effects on the intestine. The aim of this study was to investigate the effect of IGF-I on intestinal barrier function in cirrhotic rats. METHODS: In rats with carbon tetrachloride induced cirrhosis, we investigated the effect of IGF-I therapy on: (a) portal pressure; (b) intestinal histology and permeability to endotoxin and bacteria; (c) intestinal expression of cyclooxygenase 2 (COX-2) and tumour necrosis factor alpha (TNF-alpha), two factors that influence in a positive and negative manner, respectively, the integrity of the intestinal barrier; (d) intestinal permeability to 3H-mannitol in rats with bile duct ligation (BDL); and (e) transepithelial electrical resistance (TER) of polarised monolayers of rat small intestine epithelial cells. RESULTS: IGF-I therapy reduced liver collagen expression and portal pressure in cirrhotic rats, induced improvement in intestinal histology, and caused a reduction in bacterial translocation and endotoxaemia. These changes were associated with diminished TNF-alpha expression and elevated COX-2 levels in the intestine. IGF-I reduced intestinal permeability in BDL rats and enhanced barrier function of the monolayers of epithelial intestinal cells where lipopolysaccharide (LPS) caused a decrease in TER that was reversed by IGF-I. This effect of IGF-I was associated with upregulation of COX-2 in LPS treated enterocytes. CONCLUSIONS: IGF-I enhances intestinal barrier function and reduces endotoxaemia and bacterial translocation in cirrhotic rats. IGF-I therapy might be useful in the prevention of spontaneous bacterial peritonitis in liver cirrhosis.

Estudo comparativo entre os testes adotados pelo PNCEBT para o diagnóstico sorológico da brucelose em bovinos / Comparative study of serological tests for bovine brucellosis diagnosis adopted by the Brazilian Program for animal brucellosis and tuberculosis control and eradication

Avaliaram-se comparativamente as provas do antígeno acidificado tamponado (AAT), a combinação das provas de soroaglutinação lenta e 2-mercaptoetanol (2-ME) e a reação de fixação de complemento (RFC), provas preconizadas pelo Programa Nacional de Controle e Erradicação de Brucelose Tuberculose (PNCEBT). Para tanto, foram alisadas 1.061 amostras de soros bovinos. Os dados foram analisados pelo indicador kappa, adotando-se como ponto de corte o título 25 no 2-ME e 4 na RFC. Constatou-se sensibilidade relativa de 99,6%, 98,8% e 91,1%, respectivamente, para o AAT, a 2-ME e a RFC, e especificidade relativa de 83,9%, 96,2% e 100,0%. A comparação entre os testes adotados pelo programa apontou concordância boa entre o teste de triagem (AAT) e os testes confirmatórios (kappa: 2-ME = 0,80; e RFC = 0,73) e concordância ótima quando os testes confirmatórios foram comparados entre si (kappa = 0,86). No entanto foram encontrados soros com título elevado em um dos testes confirmatórios e resultado negativo no outro, o que reforça a ideia de que o diagnóstico sorológico da brucelose é mais confiável quando obtido por meio dos resultados de vários testes.

Serum samples from 1,061 bovine were analyzed by serological diagnostic techniques adopted by the Brazilian Program for Animal Brucellosis and Tuberculosis Control and Eradication in order to compare, as a screening test, the rose Bengal plate test (RBPT), and as confirmatory tests, the 2-mercaptoethanol plus standard tube agglutination test (2-ME), and the complement fixation test (CFT). Relative sensitivity of 99.6%, 98.8% and 91.1% were observed, respectively, for RBPT, 2-ME and CFT, and relative specificity of 83.9%, 96.2% and 100.0%. The agreement between tests was analyzed by the kappa statistic (2-ME cut-off = titer 25, and CFT cutoff = titer 4). RBPT showed a substantial agreement (kappa: 2-ME = 0.80; and RFC = 0.73) with the confirmatory tests, and excellent agreement between the confirmatory tests (kappa = 0.86) was observed. However sera with a negative result in one of the confirmatory tests and a high titer in the other were observed, reinforcing that the serological diagnosis of bovine brucellosis is more reliable when based on the results of several tests.

[Brain-stem auditory pathways: effects of atropine]. / Le vie acustiche troncoencefaliche: effetti dell'atropina.

The efferent pathways exert a control action on the function of the cochlear nucleus and hair cells. Acetylcholine is the neurotransmitter of the centrifugal system and its action can be blocked by Atropine. In order to give a contribution to the knowledge of the function of the efferent bundle, Auditory Brainstem Responses (ABRs) and Acoustic Reflex Latencies (ARLs) have been examined in 10 young normal subjects there was also a decrease in latency greater than or equal to 100 microseconds by at least other two waves. The only statistically significant difference was relative to the latency mean value of the wave III recorded in contralateral derivation at 11 pps. The ARLs, after the infusion of atropine, showed a statistically significant increase in 7 of the 10 cases; no change was recorded in the AR amplitude. It can be concluded that the pharmacological block of the olivo-cochlear bundle determines a delay in the neural conduction of the acoustic impulses; this finding means that the atropine can inhibit the facilitating activity of the efferent system on the brainstem afferent pathways.

[Evoked oto-acoustic emissions in retrocochlear deafness]. / Otoemissioni acustiche evocate nelle sordità retrococleari.

In order to give a contribution to the genesis of the EOAEs, we have recorded the echoes in 6 subjects affected with unilateral acoustic neuroma, surgically proven (I. group); 11 subjects with sensorineural hearing loss with electrophysiological or balance signs of retrocochlear impairment (II. group) and 10 normally hearing young subjects as control group. In this study EOAEs have been recorded in response respectively to 3 ms 1000 Hz tone-burst and to 200-5000 filtered click, both sending with 2048 stimuli, at a repetition rate of 21 pps and different stimulus intensities ranging from 40 db SPL to saturation threshold in 10 db steps. The results have shown that the EOAEs were present in half of the tested patients in response to the clicks in both I. and II. group and in all the ears to the tone-burst although the 1.0 KHz audiometric threshold mean were > 65 db HL in I. group and in a third of the subjects in the II. group. The properties of EOAEs (detection and saturation threshold, dynamic range and duration) depended on the degree of hearing loss. These results suggest that acoustic tumor could determine a wallerian degeneration of the external fibers of the VIII nerve and consequently a dysfunction of the correspondent external hair cells of the cochlea, while in the II. group a contemporary or secondary involvement of the cochlear structures is possible.

[Evoked acoustic oto-emissions: effects of atropine]. / Otoemissioni acustiche evocate: effectti dell'atropina.

The Evoked Otoacoustic Emissions (EOE) are a sinusoidal wave complex coming from the contractile properties of the cochlea and particularly of the outer hair cells. This activity is influenced by the centrifugal pathways whose transmitter is acetylcholine. In order to study the effects of the functional block of the cochlea, ten young normal subjects were examined recording the EOE before and ten mins after the i.v. infusion of 1 mg of atropine. The statistical analysis of the results has shown a significant decrease only in EOE appearance threshold in absence of modifications of the saturation level. These data have led us to believe that atropine blocking of the centrifugal pathways causes a disfunction of the outer hair cells that accept less energy to be transduced into a neural stimulus and on the other hand more energy as EOEs.

[Effects of body posture on cochlear performance]. / Effetti della posizione del corpo sulla performance cocleare.

Experimental research has demonstrated that changes in body position influence auditory function and, specifically, supine position produces a sensorineural hearing loss at low frequencies. The hypotheses to interpret these phenomena are principally referred to an increase of hydrostatic pressure of labyrinthine fluids. In order to evaluate the effects of head position on the cochlear performance a modern test battery has been performed to study cochlear function in 11 normal subjects ranged in age from 22 to 34 years. The tests (Remote Masking:RM; Brief Tone Audiometry:BTA; Critical Ratio:RC) have been evaluated in two positions: sitting upright and supine with the head at a 20 backward angle. The results of our research have shown that in all the cases, the supine position produces a significant shift of the auditory threshold at 250 and 500 Hz, and a decrease of RM values in about all of the cases. We have estimated non statistically significant differences for the RC and BTA values, in more than half of the ears tested. On the basis of the significance given to RM, BTA, RC: we can deduce that the modifications of the auditory performance related to an increase in perilymphatic hydrostatic pressure, induced by the head position are produced by an increase in rigidity of the mechanical vibratory structures of the cochlea rather than the expression of sensorineural damage.

[Stapedo-ovalar ankylosis: histomorphologic patterns]. / L'anchilosi stapedo-ovalare: reperti isto-morfologici.

This study reports the results of the histo-pathological investigation on the stapes (fragments or complets) of 46 patients (34 females and 12 males) with clinical diagnosis of stapedial otosclerosis and submitted to stapedectomy. Otospongiotic and otosclerotic areas have been found only in some cases; more frequently, erosion cavities filled with fibrous tissue and round-cells infiltration with lymphocytes and/or macrophages have been seen. Osteoclasts were observed only in few cases. Blue mantles have been observed in about half of the cases. Our findings show that non specific chronic inflammation should be more frequent than otospongiosis or otosclerotic foci, and indicate that a phlogosis could be the pathogenetic agent of this disease. This conclusion is in agreement with our previous research, and has been recently confirmed by the observations in stapes of otosclerotic patients of viral antigens and antibodies.

[Critical ratio: effects of contralateral masking on normal and pathological ears]. / Rapporto critico: effetti del mascheramento controlaterale in orecchi normali e patologici.

In order to evaluate the central interferences on the auditory efficiency, the effect of contralateral masking noise on Critical Ratio (CR) has been studied in 14 normal ears (control group), in 12 ears with cochlear disorders and in 6 with retrocochlear lesion (acoustic neuromas); in all cases the impairment was unilateral, while the other ear was normal. CR values were calculated for 1 KHz pulsed tones (duration 500 ms, rise/fall 25 ms, duty cycle of 50%); the masking noise was a wide band (90-20,000 Hz) delivered at 40 dB SL. The results have demonstrated that in the presence of contralateral masking noise, CRs don't modify both in the normal ears and in those with retrocochlear disorder, whereas they increase, almost always, in ears with cochlear deafness. These results demonstrate that the involvement of central auditory pathways, because of contralateral noise, makes the auditory efficiency worse, only in ears with cochlear dysfunctions; this behaviour seems to confirm the peripheral origin of CR.

[Psychoacoustic tests: effects of atropine]. / Test psicoacustici: effetti dell'atropina.

The efferent pathways exert a control action on the function of the cochlear nucleus and hair cells. Acetylcholine is the neurotransmitter of the centrifugal system and its action can be blocked by atropine. In order to give a contribution to the knowledge of the function of the efferent bundle and of the cochlea efficiency we examined 10 young normal subjects before and after infusion of 1 mg of atropine i.v. a battery of three psychoacoustical tests (Remote Masking, Critical Ratio and Brief Tone Audiometry). After infusion of atropine we have shown an increase of 0.25 Hz hearing threshold, an increase of RC values and a decrease of RM values. It can be concluded that the pharmacological block of the olivo-cochlear bundle determines a stiffness of outer hair cells and basilar membrane; this finding means that the atropine can inhibit the facilitating activity of the efferent system on the cochlear performance.

[Evoked acoustic oto-emissions in cochlear deafness]. / Otoemissioni acustiche evocate nelle sordità cocleari.

In order to give a contribution to the genesis of the EOAEs, we have recorded echos in 24 subjects with unilateral sudden deafness (I. group); 20 ears with Menière disease (II. group); 22 ears with progressive sensorineural hearing loss (III. group) and 10 normally hearing young subjects as control group. The results have shown that the EOAEs were present in 100% (I. group), 84.6% (II. group) and 86.3% (III. group) in response to the tone-burst; while the echos were present only in the 57.1% (I. group), 38.4% (II. group) and 45.4% (III. group) in response to the click, although the audiometric threshold mean were greater than 45 dB HL for 2-4 KHz and 1 KHz in the three experimental groups except for 2-4 KHz in the subjects with Menière disease (37.5 dB HL). The properties of EOAEs (detection and saturation threshold, dynamic range and duration) depended on the degree of hearing loss. Our results seem to corroborate the hypothesis that EOAEs could be also produced by a passive intracochlear mechanism attributable to the travelling wave of the basilar membrane provoked by the perilymph. In the normal ear this passive mechanism could be superimposed by an active mechanism, linked to the contractile activity of the outer hair cells with a consequent increase in amplitude of the EOAEs for the same stimulus intensity.