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Biomedical subjects

J Shand

Publications and source records attributed to J Shand.

30 records · Page 2Linked to original sources
PubMed1988

The use of fine bore silastic catheters to drain carcinomatous pleural effusions.

Thirty-eight patients with carcinomatous pleural effusions had pleurocentesis performed with a fine bore silastic catheter sited under ultrasound guidance. Of these, 27 proceeded to pleurodesis. In the latter group there was a recurrence rate of 3.7% (one patient). Overall there was a complication rate of 26.3% (10 patients), only 5.2% (two patients) requiring active treatment. These results compare favourably with other methods of treatment.

Aged↗
PubMed1987

Light-induced changes in corneal iridescence in fish.

The cornea of the goby Pomatoschistus minutus is iridescent. Spectral reflectance measurements show that the colour of the iridescence responds to light shifting to longer wavelengths when illuminated and shifting to shorter wavelengths when dark adapted. After 2-3 hr dark adaptation the iridescence is no longer visible.

Adaptation, Ocular↗
PubMed1984

Dark-induced cone outer segment damage in the neon tetra (Paracheirodon innesi).

The outer segment of the twin cones of the neon tetra show scrolling and vesiculation when exposed to 36 hr of continuous darkness. This disruption first begins as a rolling of the margins of the cone lamellae and proceeds to form a complex pattern of scrolls and vesicles. There is evidence that this damage can be repaired without having to return the animals to a normal light regime. Similar lamellar disruptions have been seen in the outer segments of both rods and cones of other species that have been exposed to various other light regimes including constant light.

Animals↗
PubMed1983

Endogenous circadian retinomotor movements in the neon tetra (Paracheirodon innesi).

Retinomotor movements of retinal cones and pigment epithelium melanosomes were studied in the neon tetra, Paracheirodon innesi. The cone myoids clearly contracted during the daytime, but the migration of the total population of pigment granules was less easy to see. However, when rod-shaped melanosomes were measured separately from granular-shaped melanosomes it became evident that the rod-shaped melanosomes, but not the granular melanosomes, did migrate in response to circadian changes in light intensity. Retinomotor movements of both the cones and the rod-shaped melanosomes persisted for at least 2 days in continuous darkness. Microspectrophotometric measurements of spectral transmission of small groups of melanosomes showed that absorption was greatest at shorter wavelengths, but that there was also a distinct absorbance maximum at about 480 nm.

Animals↗
PubMed1982

Changes in spectral reflexions from the iridophores of the neon tetra.

1. The iridescent stripe of the freshwater teleost, the neon tetra, changes from green in the daytime to violet-blue at night. 2. Spectral reflectance measurements were used to follow these colour changes. 3. Light causes a shift in reflectance to longer wavelengths in living fish and in isolated tissue from the lateral stripe. The change is reversed in darkness. 4. The spectral reflectance shifts to longer wavelengths when the fish is disturbed in darkness. No such colour changes were seen in fishes kept alive in 10(-4) M-reserpine. 5. Hypotonic Ringer solution causes a reflectance shift to longer wavelengths and hypertonic solution causes a shift to shorter wavelengths. 6. The iridescent reflexions from the lateral stripe which is continued across the iris originate from iridophores in the dermis. These iridophores contain regular stacks of broad, double-sided hexagonal plates that are about 10 nm thick. Each plate is contained within a pouch in the cytoplasm and is separated from its neighbour by approximately one quarter the wavelength of light. 7. A distinction is drawn between the physiologically active iridophores in the lateral stripe and iris that have broad hexagonal crystal plates which are very thin and the physiologically inactive iridophores that are also found in the iris, but in addition are found on the flanks below the lateral stripe, and on the head. These iridophores contain hexagonal crystals that are usually narrower than the active type, but are about 60-100 nm thick.

Animals↗
PubMed1977

Perceived self and ideal self ratings in relation to high and low levels of anxiety in college women.

The Cattell and Scheier IPAT Anxiety (Self Analysis) Questionnaire and the Corsini SAQS Chicago Q Sort were administered to 146 college women. Ss were divided into "high" and "low" anxiety groups on the basis of the IPAT anxiety scores. Those women with a high degree of anxiety were found to have a significantly greater discrepancy between their perceived self and ideal self concepts than did those women who had low levels of anxiety.

Anxiety↗
PubMedDate not supplied

Retinal development of West Australian dhufish, Glaucosoma hebraicum.

An investigation of retinal specializations was carried out in larval and juvenile dhufish, Glaucosoma hebraicum (Glaucosomidae, Teleostei). The development of photoreceptors and formation of the retinal mosaic was followed by light and electron microscopy. At hatching the eye was undifferentiated. Cone photoreceptors were present by day 3 posthatch (dph), when exogenous feeding began. Single and multiple cones were present in a row arrangement from 3 dph to 20 dph, when the first rod nuclei were observed. Between 20 dph and approximately 3 months posthatch (mph), the row arrangement was replaced by a square mosaic of four double cones surrounding a single cone, and the cones increased in size, with the outer segments reaching up to 30 microm in length. During the period of spatial rearrangement, triple cones were often observed. From their first appearance, rod photoreceptors were added rapidly. Investigation of ganglion cell topography in 3-mph fish that had attained the adult-like square photoreceptor mosaic was carried out using retinal wholemounts. The highest densities of neurones in the ganglion cell layer were in temporal retina but no well-defined area centralis was observed. Microspectrophotometric measurements of the visual pigments within the outer segments of the photoreceptors of 3-mph fish revealed double cones with identical absorption spectra in each member of the outer segment, and the wavelength of maximum absorption (lambda(max)) located at 522 nm. Single cones were found to possess a visual pigment with lambda(max) at 460 nm and rods with a lambda(max) of 498 nm. The results imply that the larvae and juveniles are adapted for survival in coastal waters and may be active in relatively low light levels from early stages of development.

Animals↗
PubMedDate not supplied

Topographies of retinal cone photoreceptors in two Australian marsupials.

Microspectrophotometry indicates the presence of at least three cone visual pigments in two Australian marsupials, the fat-tailed dunnart (Sminthopsis crassicaudata) and honey possum (Tarsipes rostratus). Here we have examined the distribution of cone types using antisera, JH455 and JH492, that recognize short-wavelength-sensitive (SWS) and medium-to-long-wavelength-sensitive (M/LWS) cone opsins, respectively. SWS cones were concentrated in dorso-temporal retina in the dunnart with a shallow decreasing gradient extending to the periphery (2300-1500/mm2). In the honey possum, SWS cones showed a uniform distribution (2700/mm2), except for a slight increase in a narrow peripheral band (3100/mm2). In both species, M/LWS cones dominated and their distributions were similar to those of retinal ganglion cells: a horizontal streak in the dunnart (31,000-21,000/mm2) and a shallow mid-ventral to peripheral gradient in the honey possum (37,000-26,000/mm2). A low number of cones remained unlabeled when the antisera were combined revealing further minority cone population(s). We discuss cone distributions in relation to visual capabilities and requirements of the species.

Animals↗