Lobe formation and division in the foliose lichen Xanthoparmelia conspersa

New lobe development and lobe division was studied in the foliose lichen Xanthoparmelia conspersa (Ehrh. ex. Ach.) Hale. In thalli with either the centre or margin removed, the inside edge of the perimeter, the outer edge of the reproductive centre, and fragments derived from the thallus perimeter all regenerated growing points (‘lobe primordia’) within a year. Thalli possessing isidia had the greatest ability to regenerate growing points. In reproductive thalli, there was a positive correlation between the density of new growing points and thallus size. When fragments were cut from the perimeters of mature X. conspersa thalli and glued to pieces of slate, the ratio of growing points to mature lobes increased over 54 months. Lobes within a thallus exhibited different degrees of bifurcation. In some bifurcating lobes, the point of origin of the bifurcation advanced at the same rate as the lobe tips over 4 months but in most lobes, the bifurcation point either advanced less rapidly than the lobe tips or retreated from its original location. Removing adjacent lobes had no significant effect on the radial growth of a lobe over 4 months or on the location of the bifurcation point but it increased the number of growing points. These results suggest that for X. conspersa: 1) all portions of of thalli can regenerate growing points, 2) few growing points actually develop into mature lobes, 3) individual lobes within a thallus grow and divide differently, and 4) adjacent lobes inhibit the development of growing points on their neighbours.

Temporal lobe pathology in neurodegenerative disease:a comparative study of eight disorders with special reference to the hippocampus

The temporal lobe is a major site of pathology in a number of neurodegenerative diseases. In this chapter, the densities of the characteristic pathological lesions in various regions of the temporal lobe were compared in eight neurodegenerative disorders, viz., Alzheimer’s disease (AD), Down’s syndrome (DS), dementia with Lewy bodies (DLB), Pick’s disease (PiD), corticobasal degeneration (CBD), progressive supranuclear palsy (PSP), sporadic Creutzfeldt-Jakob disease (sCJD), and neuronal intermediate filament inclusion disease (NIFID). Temporal lobe pathology was observed in all of these disorders most notably in AD, DS, PiD, sCJD, and NIFID. The regions of the temporal lobe affected by the pathology, however, varied between disorders. In AD and DS, the greatest densities of ?-amyloid (A?) deposits were recorded in cortical regions adjacent to the hippocampus (HC), DS exhibiting greater densities of A? deposits than AD. Similarly, in sCJD, greatest densities of prion protein (PrPsc) deposits were recorded in cortical areas of the temporal lobe. In AD and PiD, significant densities of neurofibrillary tangles (NFT) and Pick bodies (PB) respectively were present in sector CA1 of the HC while in CBD, the greatest densities of tau-immunoreactive neuronal cytoplasmic inclusions (NCI) were present in the parahippocampal gyrus (PHG). Particularly high densities of PB were present in the DG in PiD, whereas NFT in AD and Lewy bodies (LB) in DLB were usually absent in this region. These data confirm that the temporal lobe is an important site of pathology in the disorders studied regardless of their molecular ‘signature’. However, disorders differ in the extent to which the pathology spreads to affect the HC which may account for some of the observed differences in clinical dementia.

Beta-amyloid (beta/A4) deposition in the medial temporal lobe in Down's syndrome: effects of brain region and patient age

The density of diffuse, primitive, classic and compact beta-amyloid (beta/A4) deposits was studied in the medial temporal lobe in 12 cases of Down's syndrome (DS) from 38 to 67 years of age. Total beta/A4 deposit density was greater in the adjacent cortex compared with regions of the hippocampus, and these differences were similar within each age group of patients. The ratio of the primitive to diffuse deposits was greater in the hippocampus than in the adjacent cortex. Total beta/A4 density did not vary significantly with patient age. However, the density of the diffuse deposits exhibited a parabolic, and the primitive, classic and compact deposits an inverted parabolic, response with age. Hence, in DS, (1) beta/A4 density remains relatively constant with age, (2) differences in beta/A4 density between the hippocampus and adjacent cortex are established at an early age, and (3) mature beta/A4 subtype formation depends on brain region and patient age.

A comparison of beta-amyloid deposition in the medial temporal lobe in sporadic Alzheimer's disease, Down's syndrome and normal elderly brains

The density of beta-amyloid (A beta) deposits was studied in the medial temporal lobe in non-demented individuals and in sporadic Alzheimer's disease (SAD) and Down's syndrome (DS). No A beta deposits were recorded in six of the non-demented cases, while in a further eight cases, these were confined to either the lateral occipitotemporal or parahippocampal gyrus. The mean density of A beta deposits in the cortex was greater in SAD and DS than in non-demented cases but with overlap between patient groups. The mean density of A beta deposits was greater in DS than SAD consistent with a gene dosage effect. The ratio of primitive to diffuse A beta deposits was greater in DS and in non-demented cases than in SAD and the ratio of classic to diffuse deposits was lowest in DS. In all groups, A beta deposits occurred in clusters which were often regularly distributed. In the cortex, the dimension of the A beta clusters was greater in SAD than in the non-demented cases and DS. The data suggest that the development of A beta pathology in the hippocampus could be a factor in the development of DS and SAD. Furthermore, the high density of A beta deposits, and in particular the high proportion of primitive type deposits, may be important in DS while the development of large clusters of A beta deposits may be a factor in SAD.

Neuronal network dynamics during epileptogenesis in the medial temporal lobe

Epilepsy is one of the most common neurological disorders, a large fraction of which is resistant to pharmacotherapy. In this light, understanding the mechanisms of epilepsy and its intractable forms in particular could create new targets for pharmacotherapeutic intervention. The current project explores the dynamic changes in neuronal network function in the chronic temporal lobe epilepsy (TLE) in rat and human brain in vitro. I focused on the process of establishment of epilepsy (epileptogenesis) in the temporal lobe. Rhythmic behaviour of the hippocampal neuronal networks in healthy animals was explored using spontaneous oscillations in the gamma frequency band (SγO). The use of an improved brain slice preparation technique resulted in the natural occurence (in the absence of pharmacological stimulation) of rhythmic activity, which was then pharmacologically characterised and compared to other models of gamma oscillations (KA- and CCh-induced oscillations) using local field potential recording technique. The results showed that SγO differed from pharmacologically driven models, suggesting higher physiological relevance of SγO. Network activity was also explored in the medial entorhinal cortex (mEC), where spontaneous slow wave oscillations (SWO) were detected. To investigate the course of chronic TLE establishment, a refined Li-pilocarpine-based model of epilepsy (RISE) was developed. The model significantly reduced animal mortality and demonstrated reduced intensity, yet high morbidy with almost 70% mean success rate of developing spontaneous recurrent seizures. We used SγO to characterize changes in the hippocampal neuronal networks throughout the epileptogenesis. The results showed that the network remained largely intact, demonstrating the subtle nature of the RISE model. Despite this, a reduction in network activity was detected during the so-called latent (no seizure) period, which was hypothesized to occur due to network fragmentation and an abnormal function of kainate receptors (KAr). We therefore explored the function of KAr by challenging SγO with kainic acid (KA). The results demonstrated a remarkable decrease in KAr response during the latent period, suggesting KAr dysfunction or altered expression, which will be further investigated using a variety of electrophysiological and immunocytochemical methods. The entorhinal cortex, together with the hippocampus, is known to play an important role in the TLE. Considering this, we investigated neuronal network function of the mEC during epileptogenesis using SWO. The results demonstrated a striking difference in AMPAr function, with possible receptor upregulation or abnormal composition in the early development of epilepsy. Alterations in receptor function inevitably lead to changes in the network function, which may play an important role in the development of epilepsy. Preliminary investigations were made using slices of human brain tissue taken following surgery for intratctable epilepsy. Initial results showed that oscillogenesis could be induced in human brain slices and that such network activity was pharmacologically similar to that observed in rodent brain. Overall, our findings suggest that excitatory glutamatergic transmission is heavily involved in the process of epileptogenesis. Together with other types of receptors, KAr and AMPAr contribute to epilepsy establishment and may be the key to uncovering its mechanism.

Laminar distribution of β-amyloid (Aβ) peptide deposits in the frontal lobe in familial and sporadic Alzheimer's disease

To determine whether genetic factors influence frontal lobe degeneration in Alzheimer's disease (AD), the laminar distributions of diffuse, primitive, and classic β-amyloid (Aβ) peptide deposits were compared in early-onset familial AD (EO-FAD) linked to mutations of the amyloid precursor protein (APP) or presenilin 1 (PSEN1) gene, late-onset familial AD (LO-FAD), and sporadic AD (SAD). The influence of apolipoprotein E (Apo E) genotype on laminar distribution was also studied. In the majority of FAD and SAD cases, maximum density of the diffuse and primitive Aβ deposits occurred in the upper cortical layers, whereas the distribution of the classic Aβ deposits was more variable, either occurring in the lower layers, or a double-peaked (bimodal) distribution was present, density peaks occurring in upper and lower layers. The cortical layer at which maximum density of Aβ deposits occurred and maximum density were similar in EO-FAD, LO-FAD and SAD. In addition, there were no significant differences in distributions in cases expressing Apo E ε4 alleles compared with cases expressing the ε2 or ε3 alleles. These results suggest that gene expression had relatively little effect on the laminar distribution of Aβ deposits in the frontal lobe of the AD cases studied. Hence, the pattern of frontal lobe degeneration in AD is similar regardless of whether it is associated with APP and PSEN1, mutation, allelic variation in Apo E, or with SAD.

A spatial pattern analysis of β-amyloid (Aβ) deposition in the temporal lobe in Alzheimer's disease

To determine the factors influencing the distribution of β-amyloid (Aβ) deposits in Alzheimer's disease (AD), the spatial patterns of the diffuse, primitive, and classic Aβ deposits were studied from the superior temporal gyrus (STG) to sector CA4 of the hippocampus in six sporadic cases of the disease. In cortical gyri and in the CA sectors of the hippocampus, the Aβ deposits were distributed either in clusters 200-6400 μm in diameter that were regularly distributed parallel to the tissue boundary or in larger clusters greater than 6400 μm in diameter. In some regions, smaller clusters of Aβ deposits were aggregated into larger 'superclusters'. In many cortical gyri, the density of Aβ deposits was positively correlated with distance below the gyral crest. In the majority of regions, clusters of the diffuse, primitive, and classic deposits were not spatially correlated with each other. In two cases, double immunolabelled to reveal the Aβ deposits and blood vessels, the classic Aβ deposits were clustered around the larger diameter vessels. These results suggest a complex pattern of Aβ deposition in the temporal lobe in sporadic AD. A regular distribution of Aβ deposit clusters may reflect the degeneration of specific cortico-cortical and cortico-hippocampal pathways and the influence of the cerebral blood vessels. Large-scale clustering may reflect the aggregation of deposits in the depths of the sulci and the coalescence of smaller clusters.

Testicular volume and reproductive status of Wild Callithrix jacchus

ARAÚJO, Arrilton ; SOUSA, Maria Bernardete Cordeiro . Testicular volume and reproductive status of Wild Callithrix jacchus. International Journal of Primatology, v.29, p.1355–1364, 2008. DOI 10.1007/s10764-008-9291-4

Testicular volume and reproductive status of Wild Callithrix jacchus

ARAÚJO, Arrilton ; SOUSA, Maria Bernardete Cordeiro . Testicular volume and reproductive status of Wild Callithrix jacchus. International Journal of Primatology, v.29, p.1355–1364, 2008. DOI 10.1007/s10764-008-9291-4

Verbal emotional memory in children and adolescents with temporal lobe epilepsy: A first study

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Fases do desenvolvimento e diferenciação testicular em cutias (Dasyprocta aguti) criadas em cativeiros

A cutia (Dasyprocta aguti) é um roedor silvestre encontrado amplamente na região Nordeste do Brasil. É uma espécie muito utilizada pela população humana de baixa renda como fonte alternativa de proteína na alimentação. Foram utilizadas 31 cutias, machos, provenientes da Universidade Federal do Piauí (FUFPI), Estado do Piauí e da Escola Superior de Agricultura de Mossoró Estado do Rio Grande do Norte. Os animais foram divididos em grupos etários desde o nascimento até os 14 meses de idade. O diâmetro nuclear médio foi obtido pela medida de 10 núcleos do tipo celular estudado em cada testículo, no estágio 1 do ciclo do epitélio seminífero. Nos animais que não apresentaram o epitélio organizado em estágios bem definidos em virtude da idade, foram feitas medidas em secções transversais escolhidas somente pelo contorno circular. O início da assincronia do processo espermatogênico foi observado a partir dos seis meses de idade. A puberdade, na cutia Dasyprocta aguti, foi definitivamente estabelecida a partir dos nove meses de idade, pois estavam presentes todos os tipos celulares e espermatozóides liberados no lume tubular em grande parte do parênquima testicular.

Análise histométrica do desenvolvimento testicular de cutias (Dasyprocta aguti) criadas em cativeiros

Foi estudado, por meio da histometria, o desenvolvimento testicular em 31 cutias da espécie Dasyprocta aguti desde o nascimento até 14 meses de idade. O diâmetro e a área, médios, foram obtidos a partir de 30 secções transversais de cordões e/ou túbulos seminíferos, em cada testículo, utilizando-se sistema de computadorizado de analises de imagem e uma ocular micrométrica Zeiss CPL 10X, acoplada a uma objetiva de 40X. As proporções volumétricas do testículo foram obtidas com o método estereométrico, segundo Elias, Henning e Schwartz¹. O diâmetro tubular médio apresentou crescimento lento desde o nascimento até os oito meses de idade, nas duas metodologias empregadas. Quando foi usada a ocular micrométrica observou-se que, a partir de nove meses, o diâmetro tubular teve um crescimento acelerado, chegando a duplicar o seu valor, se comparado com grupo etário que o antecedia. A proporção volumétrica dos cordões testiculares e túbulos seminíferos cresceu gradualmente, atingindo, aos nove meses, seu valor máximo (86,50%). As células de Leydig apresentaram proporção volumétrica decrescente, e seus maiores valores foram expressivos do nascimento até quatro meses de idade (7,00 ± 1,77% a 9,55 ± 0,64%) e mínimos a partir de nove meses, tendendo ainda a uma estabilização. O estroma diminuiu com a evolução da idade caindo bruscamente a partir da puberdade. Conclui-se que o diâmetro dos cordões testiculares e túbulos seminíferos apresentou maior crescimento, coincidindo com o início da puberdade e a proporção volumétrica das células de Leydig encontrou-se, respectivamente, mais alta e mais baixa no mesmo período.

Testicular arteries systematization based on different levels of scrotal configuration in caprines

O objetivo deste trabalho foi analisar a distribuição dos vasos arteriais nos testículos em caprinos com diferentes graus de divisão escrotal. A configuração escrotal foi classificada da seguinte forma: Grupo I: constituído por caprinos com escroto único, Grupo II: com escroto separado até a metade do testículo e Grupo III: com separação escrotal estendendo-se além da metade do testículos. As artérias foram injetadas e coradas com solução de acetado de vinil, sendo os orgãos (30 pares) submetidos à corrossão para obtenção dos moldes vasculares. As artérias testiculares emergem da aorta abdominal, com trajeto retilíneo, atravessam o canal inguinal, apresentam-se espiraladas e envolvidas parcialmente pelo plexo pampiniforme. Próximo à extremidade caudada do testículo, dividem-se mais freqüentemente nos ramos cranial e caudal, os quais emitem vasos colaterais, de onde emergem ramos penetrantes. Os testículos dos animais com nível intermediário de divisão escrotal (Grupo II) apresentam menor quantidade destes ramos, sendo os quadrantes mais povoados o ventrolateral e o dorsolateral. Conclui-se que a origem, o trajeto e a distribuição das artérias testiculares não apresentam variações relacionadas ao grau de divisão escrotal em caprinos.

Influence of the bipartite scrotum on the testicular and scrotal temperatures in goats

O objetivo deste trabalho foi avaliar a influência do grau de bipartição escrotal e do período do ano sobre a termorregulação escroto-testicular em caprinos criados no Estado do Piauí. Foram utilizados 18 reprodutores caprinos machos, divididos em três grupos de seis animais: O Grupo I contendo caprinos com escroto simples, o Grupo II, caprinos com escroto bipartido até 50% do comprimento testicular e o Grupo III, caprinos com bipartição superior a 50% do comprimento testicular. Os parâmetros avaliados foram as temperaturas do escroto, testículo e funículo espermático, obtidas de forma invasiva, com um termômetro digital termoacoplável, e não invasiva, com um pirômetro, nos terços proximal, médio e distal. Os dados foram coletados nos períodos seco (outubro-novembro) e chuvoso (fevereiro-março) do ano, bem como, nos turnos da manhã (6h00 às 7h00) e tarde (14h00 às 15h00). Os resultados foram submetidos à análise de variância (ANOVA) seguida do teste SNK para comparação das médias (p<0,05). O período do ano interferiu na termorregulação escroto-testicular, pois no período seco as temperaturas do escroto, testículo e funículo espermático foram mais elevadas que as observadas no período chuvoso. O grau de bipartição do escroto foi outro fator que modificou a temperatura escroto-testicular, já que os caprinos que apresentaram escroto com maior grau de bipartição demonstraram as menores médias das temperaturas escroto-testiculares em ambos os períodos e turnos avaliados. Conclui-se, portanto, que tanto o período do ano quanto o grau de bipartição do escroto influenciaram o processo de termorregulação escroto-testicular em caprinos.

A NOVEL NON-LETHAL LAPAROSCOPIC APPROACH TO DETECT INTERSEX (TESTICULAR OOCYTES) IN LARGEMOUTH BASS (MICROPTERUS SALMOIDES) AND SMALLMOUTH BASS (MICROPTERUS DOLOMIEU)

The appearance of testicular oocytes (TO) in wild fish populations has received considerable attention in the scientific literature and public media. Current methods to quantify TO are lethal; instead, a non-lethal alternative was examined. Laparoscopic insertion into the genital pore allowed internal visualization of the gonad and detection of TO by collecting five testis biopsies in smallmouth bass Micropterus dolomieu and largemouth bass Micropterus salmoides. Overall, biopsies quantified similar levels of TO detection and severity to conventional transverse sectioning with less than 10% mortality. Suitability of surgical anesthetics, tricaine methanesulfonate and electronarcosis were examined in laboratory and field applications. Electronarcosis had the added benefit of rapid sex identification and immediate release of female fish with minimal trauma, representing significant benefits when sampling small or compromised populations. Laparoscopy may be useful for monitoring the prevalence and severity of TO in these fish species when lethal sampling is not a desired outcome.