A study of retinal neurodegeneration using optical coherence tomography in type 2 diabetes mellitus patients without retinopathy: A cross-sectional study

Background: Neurodegeneration of retina (retinal diabetic neuropathy) is the earlier sign of diabetes mellitus before the appearance of any vascular sign of diabetic retinopathy. Hence, through neurodegenerative changes, we can diagnose and monitor the early neuronal damage of the retina. Objectives: The objective of the study were to establish whether the retinal neurodegeneration is earlier than vasculopathic changes in patients with diabetes and their relationship with the duration of diabetes. Materials and Methods: A total of 180 diabetic patients and 164 healthy controls were collected from a rural-based tertiary care hospital in West Bengal for this cross-sectional study. All have gone through proper history taking, comprehensive ocular examinations and spectral-domain optical coherence tomography imaging to detect the thickness of retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL). Results: Our study showed that the RNFL thickness of the right and left eyes for the cases was 37.62 μm and 37.68 μm, respectively, and that for controls were 39.68 μm and 39.70 μm, respectively. The GCL thickness of the right and left eyes was 32.63 μm and 32.43 μm, respectively, in cases and that for controls were 33.73 μm and 33.87 μm, respectively. In respect of the duration of diabetes, mean RNFL thickness of the right and left eyes for <1 year, 1–2 years, and >2 years was 40.20 μm and 40.03 μm; 38.17 μm and 38.31 μm; and 35.48 μm and 35.69 μm, respectively. Mean GCL thickness of the right and left eyes for <1 year, 1–2 years, and >2 years was 34.25 μm and 33.72 μm; 31.98 μm and 31.44 μm; and 30.82 μm and 31.35 μm, respectively. The data were analyzed by appropriate statistical methods. Conclusion: This study showed that thinning of RNFL and GCL occurred in diabetes before the appearance of microaneurysm.

The effects of unrelated offspring whistle calls on capybaras (Hydrochoerus hydrochaeris) / Os efeitos do chamado de assobio de filhotes não aparentados em capivaras (Hydrochoerus hydrochaeris)

Parent-offspring vocal communication, such as the isolation call, is one of the essential adaptations in mammals that adjust parental responsiveness. Thus, our aim was to test the hypothesis that the function of the capybara infants' whistle is to attract conspecifics. We designed a playback experiment to investigate the reaction of 20 adult capybaras (seven males and 13 females) to pups' whistle calls – recorded from unrelated offspring – or to bird song, as control. The adult capybaras promptly responded to playback of unrelated pup whistles, while ignoring the bird vocalisation. The adult capybaras took, on average, 2.6 ± 2.5 seconds (s) to show a response to the whistles, with no differences between males and females. However, females look longer (17.0 ± 12.9 s) than males (3.0 ± 7.2 s) toward the sound source when playing the pups' whistle playback. The females also tended to approach the playback source, while males showed just a momentary interruption of ongoing behaviour (feeding). Our results suggest that capybara pups' whistles function as the isolation call in this species, but gender influences the intensity of the response.

A comunicação vocal entre pais-filhotes, tal como os chamados de isolamento, é uma das adaptações essenciais nos mamíferos para o ajuste da resposta parental. Assim, nosso objetivo foi testar a hipótese de que a função do chamado de assobio em filhotes de capivara é para atrair co-especificos. Delineamos um experimento via playback para investigar a reação de 20 capivaras adultas (sete machos e 13 fêmeas) ao chamado de assobio de filhotes não aparentados e como controle usamos o chamado de um pássaro. As capivaras adultas prontamente responderam ao playback de assobios de filhotes não aparentados, enquanto ignoraram as vocalizações de pássaro. As capivaras levaram, em media 2,6 ± 2,5 segundos (s) para mostrar a resposta para os assobios, não havendo diferença entre machos e fêmeas. No entanto, fêmeas permanecem mais tempo (17,0 ± 12,9 s) do que os machos (3,0 ± 7,2 s) para retornar da fonte sonora após o playback de assobio iniciar. As fêmeas também tendem a aproximar-se da fonte sonora, enquanto os machos fazem uma breve interrupção do comportamento que estão engajados (comendo). Os resultados sugerem que a função do chamado de assobio de filhotes de capivaras é um chamado de isolamento na espécie e que o gênero influencia a intensidade da resposta.

The effects of unrelated offspring whistle calls on capybaras (Hydrochoerus hydrochaeris)

Parent-offspring vocal communication, such as the isolation call, is one of the essential adaptations in mammals that adjust parental responsiveness. Thus, our aim was to test the hypothesis that the function of the capybara infants' whistle is to attract conspecifics. We designed a playback experiment to investigate the reaction of 20 adult capybaras (seven males and 13 females) to pups' whistle calls recorded from unrelated offspring or to bird song, as control. The adult capybaras promptly responded to playback of unrelated pup whistles, while ignoring the bird vocalisation. The adult capybaras took, on average, 2.6 ± 2.5 seconds (s) to show a response to the whistles, with no differences between males and females. However, females look longer (17.0 ± 12.9 s) than males (3.0 ± 7.2 s) toward the sound source when playing the pups' whistle playback. The females also tended to approach the playback source, while males showed just a momentary interruption of ongoing behaviour (feeding). Our results suggest that capybara pups' whistles function as the isolation call in this species, but gender influences the intensity of the response.

A comunicação vocal entre pais-filhotes, tal como os chamados de isolamento, é uma das adaptações essenciais nos mamíferos para o ajuste da resposta parental. Assim, nosso objetivo foi testar a hipótese de que a função do chamado de assobio em filhotes de capivara é para atrair co-especificos. Delineamos um experimento via playback para investigar a reação de 20 capivaras adultas (sete machos e 13 fêmeas) ao chamado de assobio de filhotes não aparentados e como controle usamos o chamado de um pássaro. As capivaras adultas prontamente responderam ao playback de assobios de filhotes não aparentados, enquanto ignoraram as vocalizações de pássaro. As capivaras levaram, em media 2,6 ± 2,5 segundos (s) para mostrar a resposta para os assobios, não havendo diferença entre machos e fêmeas. No entanto, fêmeas permanecem mais tempo (17,0 ± 12,9 s) do que os machos (3,0 ± 7,2 s) para retornar da fonte sonora após o playback de assobio iniciar. As fêmeas também tendem a aproximar-se da fonte sonora, enquanto os machos fazem uma breve interrupção do comportamento que estão engajados (comendo). Os resultados sugerem que a função do chamado de assobio de filhotes de capivaras é um chamado de isolamento na espécie e que o gênero influencia a intensidade da resposta.