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A detailed cytoarchitectonic atlas of the chinchilla cochlear nucleus complex was prepared in the transverse plane with the Nissl method. Subdivisions of the cochlear nucleus were defined on the basis of cell size, cell packing density, and, in some cases, on cytological features of cell types. In general, the chinchilla cochlear nucleus has an organizational plan similar to that described for other mammalian species. As in other rodents, the chinchilla has a large and well-developed dorsal cochlear nucleus consisting of three distinct layers. The ventral cochlear nucleus consists of two distinct nuclear masses, a posterior nuclear group and an anterior nuclear group, each composed of several subdivisions, which are qualitatively similar to those described for other mammals. Thus it is now possible to compare detailed observations, such as tonotopic maps, in the chinchilla with findings from the analogous cell populations in other mammals, such as the cat, with considerable precision. In the chinchilla, three cell groups, previously undescribed in mammals, have been defined and their counterparts in the cat identified.

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Purpose To measure the deformation of the human optic nerve head (ONH) and peripapillary tissue (PPT) in response to acute intraocular pressure (IOP) elevation. Methods The ONH and PPT of 14 human donor globes were imaged with high-frequency ultrasonography during inflation testing from 5 to 30 mm Hg. A correlation-based speckle tracking algorithm was used to compute tissue displacements, and the through-thickness, in-plane, and shear strains were calculated by using least-squares strain estimation methods. The ONH and PPT were segmented along the anterior-posterior direction and the nasal-temporal direction. Regional displacements and strains were analyzed and compared. Results The ONH displaced more posteriorly than the PPT in response to an acute IOP increase. Scleral canal expansion was minimal but correlated with ONH posterior displacement at all IOP levels. Through-thickness compression was concentrated in the anterior of both the ONH and the PPT. Shear was concentrated in the vicinity of the canal with higher shear in the peripheral ONH than the central ONH and higher shear in the PPT near the scleral canal than that further away from the canal. Conclusions High-resolution ultrasound speckle tracking showed a displacement mismatch between the ONH and the PPT, larger compressive strains in the direction of IOP loading in the anterior ONH and PPT, and higher shear strains in the periphery of ONH in response to acute IOP elevation in the human eye. These findings delineate the deformation patterns within and around the ONH and may help understand IOP-associated optic nerve damage.

The present paper examines the issue of hidden drug abuse in Hong Kong. Although official statistics show that the reported number of drug-abuse cases has been in decline in recent years, it has been reported that drug abusers tend to hide themselves at home to take drugs; thus, they are not discovered easily by the law enforcement and social control agents who report drug abuse cases to the Central Registry of Drug Abuse, resulting in the decrease in the reported number of drug-abuse cases. This “dark figure” phenomenon is a reflection of the official figure and reporting behavior, not the actual situation of drug abuse in Hong Kong. Through in-depth interviews of 30 ex-drug addicts, the majority of them started drug taking in early youth, the present paper identifies five stages of drug taking from social acquaintance to social isolation. It argues that although drug taking among abusers is a kind of social activity in their initial stage of drug use, they become socially isolated when their drug use is prolonged. Several reasons are identified, including users' easy accessibility to drugs and changes in the popularity of drugs and use of drug equipment. Most importantly, the hidden process is triggered and aggravated by numerous negative drug effects, such as decline in physical health, weak physical appearance leading to self-perceived discrimination, co-occurrence of psychiatric symptoms of increased anxiety and suspicion, and decline of trust among peers due to prolonged drug abuse. Possible solutions associated with clinical interventions, legislative policies, and law-enforcement operations are proposed.