Comparative morphology of the scales of roundscale spearfish Tetrapturus georgii and white marlin Kajikia albida.

The comparative morphology of the scales of roundscale spearfish Tetrapturus georgii and white marlin Kajikia albida was investigated. In addition, variation in scale morphology across different body regions within each species was analysed. Although considerable morphological variation was observed among scales from different body regions in both species, scales of K. albida generally have pointed anterior ends, fewer posterior points and are more heavily imbricated than those of T. georgii, which are frequently rounded anteriorly, often have many posterior points and are separated farther within the skin. In all sampled body regions and individuals, scales of T. georgii are significantly broader and have a lower length-to-width aspect ratio than those of K. albida. Superficial to the scales are denticular plates, which are ossified formations occurring on the surface layer of the epidermis; these were observed and described for T. georgii, K. albida and blue marlin Makaira nigricans. Detailed scale descriptions allow for a more accurate characterization of the variation within and differences between these two species and could potentially be a valuable tool for investigating istiophorid systematics.

Osteology of the crescent gunnel Pholis laeta and the phylogeny of the family Pholidae (Cottiformes, Zoarcoidei).

This study provides a complete description of the osteology of the crescent gunnel Pholis laeta based on cleared-and-stained specimens and X-rays to help provide sufficient morphological data to generate a robust phylogeny for the family Pholidae. Pholis laeta exhibits high variation in the structure of its caudal skeleton. The length of the preural (pu)2 neural spine is variably reduced (most common) or elongated (i.e. of similar length to that of pu3). Additionally, the neural spine of pu3 is either bifurcated or single. These results document and describe characters useful for phylogenetic inference of the family, including the insertion pattern of anal-fin pterygiophores between haemal spines. Pholidae was recovered as monophyletic (synapomorphies: ribs absent, haemonephropophyses present, gill membranes broadly joined, first neural arch fused to centrum, first anal-fin spine very robust, the dorsal fin comprises only spines and the presence of five branchiostegals), with monophyletic genera Pholis and Apodichthys (Rhodymenichthys is monotypic) and Apodichthys and Rhodymenichthys as sister taxa. The elongation of its pu2 neural spine defines Pholis and synapomorphies for Apodichthys include five infraorbital bones, no pelvic fin, a hypertrophied first anal-fin spine, the presence of two or three empty interhaemal spaces after the anteriormost anal-fin spine and having 35-46 abdominal vertebrae. Apodichthys and Rhodymenichthys are sister taxa based on the continuity of the caudal fin with the dorsal and anal fins and uniform colouration. Future study is needed to more fully resolve the interrelationships of species within Pholidae (especially the genus Pholis) and solidify the position of Pholidae within the Zoarcoidei.

New records of larval stages of the eel cod genus Muraenolepis Günther 1880 (Gadiformes: Muraenolepididae) from the western Antarctic Peninsula.

Three newly discovered larval specimens of the genus Muraenolepis collected from the waters of the western Antarctic Peninsula are described. Knowledge of their natural history is sparse and information about their early life history is based on only a few larval stages. Here, the available literature on larval eel cods is reviewed, and the specimens placed in context.

Effect of Intraoperative Phenylephrine Infusion on Redistribution Hypothermia During Cesarean Delivery Under Spinal Anesthesia.

An observational clinical study to evaluate the effect of phenylephrine infusion on maternal temperatures during scheduled cesarean delivery under spinal anaesthesia was conducted in 40 ASA physical status II parturients. Following placement of spinal anesthesia, phenylephrine infusion was initiated at 40 µg/min and titrated to maintain mean arterial pressure within 20 percent of baseline. Maternal oral temperature, heart rate, and blood pressure were measured at baseline, spinal placement, every 10 minutes thereafter for 60 minutes. Phenylephrine dose received was documented every ten minutes. The range in maternal temperature change was 0.06-0.29°C. The lowest recorded temperature was 36.3°C. Decreased maternal temperature was associated with duration of anesthesia and cumulative phenylephrine dose in a univariate model (P<0.001 for all). The multivariable model showed an association between a greater decrease in maternal temperature with larger doses of phenylephrine being administered.

Sexual dimorphism in longnose gar Lepisosteus osseus.

The present study of Lepisosteus osseus dimorphism expands upon previous work by examining a broader array of morphometric characters while removing the bias associated with overall body length. A stepwise discriminant function analyses (swDFA) found that five characters best distinguish the sexes: head width, mid-snout width, anal-fin height, anal-fin width and prepectoral-fin length. Discriminant function analyses (DFA) with the five characters yields misclassification rates of 23·5% for females and 9·7% for males. Subsequent DFA using these five characters plus standard length yields misclassification rates of only 8·8% for females and 6·2% for males. The data presented here reveal differences in head and anal-fin shape between male and female L. osseus that may have evolved to enhance predatory abilities or competitive abilities during reproduction. This study is the first to find that L. osseus exhibits sexual dimorphism in characters without the biases of overall size.

Beneficial effects of small-incision cataract surgery in patients demonstrating reduced ocular blood flow characteristics.

PURPOSE: To investigate intraocular pressure (IOP) and ocular haemodynamics following small incision cataract surgery. METHODS: Systemic and ocular haemodynamics, and IOP, were measured pre-operatively and 1 month post-operatively, in 25 eyes of 25 patients (mean age 72.6+/-7.9 years) scheduled for small incision cataract surgery and intraocular lens implantation; these values were compared to an untreated age-matched healthy group (n=25, mean age 72.3+/-5.0 years). For each eye, the Ocular Blood Flow Analyser (OBFA, Paradigm Inc., UT, USA) was used to obtain measurements of IOP, pulsatile ocular blood flow (POBF), pulse volume (PV), ocular pulse amplitude (PA), and pulse rate (PR). Systemic blood pressure measurements were obtained at each visit. Pre- and post-operative values for the cataract group were compared using repeated measures analysis of variance, and compared to the normal group using analysis of variance. RESULTS: Pre-operatively, IOP was significantly higher in the cataract group compared to the age-matched normal control group (P<0.001). Cataract surgery resulted in a significant 16.7% reduction in IOP (P=0.001). Consequently, the post-operative IOP in the cataract group was similar to that of the normal group (P>0.05). Both pre- and post-operative POBF and PV values for the cataract group were significantly lower than for the normal age-matched group (P<0.0125). Small incision cataract surgery led to an 8.3% post-operative increase in POBF (P=0.0118) and 15.5% increase in PV (P<0.001). No changes in PA or PR were evident. CONCLUSION: These data suggest that cataract patients exhibit higher IOP and reduced ocular perfusion characteristics compared to an age-matched normal healthy group. Following cataract surgery, IOP reduced and ocular pulsatility improved.

Ocular haemodynamic responses to induced hypercapnia and hyperoxia in glaucoma.

AIM: To determine the ocular haemodynamic response to gas perturbations in glaucoma. METHODS: Intraocular pressure (IOP), systemic systolic and diastolic blood pressure (SBP and DBP), and retrobulbar blood flow velocities, measured by colour Doppler imaging (CDI), were recorded at two visits. CDI was used to measure peak systolic and end diastolic velocities (PSV and EDV) and resistance index (RI) in the ophthalmic artery (OA), central retinal artery (CRA), and short posterior ciliary arteries (SPCAs). At the first visit, measurements were taken at baseline (B1: breathing room air) and during isoxic hypercapnia (end tidal PCO(2) increased 15% above baseline) in 16 normal subjects and 12 patients with glaucoma. On another day, measurements were repeated at a second baseline (B2) and during hyperoxia (100% oxygen breathing) for 15 normal subjects and 13 glaucoma patients. Baseline systemic data were compared using paired t tests; REANOVA was performed to compare group differences at baseline and to determine the vessel response to each condition. Fisher's LSD was used for post hoc comparison. RESULTS: Baseline OA PSV was lower for the glaucoma than for the normal group (p = 0.047); the groups were otherwise similar at baseline. IOP demonstrated no response to hypercapnia, but reduced during hyperoxia for both the normal subjects (p<0.0001) and glaucoma patients (p = 0.04). During hypercapnia, SBP increased in normal subjects (p = 0.03) and glaucoma patients (p = 0.01); DBP increased in normal subjects (p = 0.021). There was a corresponding increase in ocular perfusion pressure (OPP) for normal subjects (p = 0.01) and glaucoma subjects (p = 0.028), and as a result OPP was included as a covariate in the REANCOVA model. Hypercapnia resulted in increased PSV in the CRA of normal subjects (p = 0.035) and increased PSV and EDV in the SPCAs of glaucoma patients (p = 0.041 and p = 0.030 respectively). Hyperoxia resulted in reduced PSV and EDV in the ophthalmic arteries of normal subjects only (p = 0.001 and 0.031 respectively). CONCLUSIONS: These findings suggest the presence of relative vasoconstriction in glaucoma patients, which is at least partially reversed by hypercapnia.

Epilepsy patients treated with vigabatrin exhibit reduced ocular blood flow.

BACKGROUND/AIM: Reduced cerebral blood flow and decreased glucose metabolism have been identified in epilepsy patients receiving vigabatrin. It is likely that such a change may extend to the eye and may be linked to previously reported irreversible visual field defects. The aim of this study was to determine whether patients who have undergone anti-epileptic drug (AED) therapy with vigabatrin have altered ocular haemodynamics. METHODS: The study cohort comprised 11 normal subjects (mean age 42.6 (SD 12.7) years and 17 epilepsy patients, of which 10 were either currently or previously treated with vigabatrin (38.6 (11.7) years) and seven were treated with AEDs excluding vigabatrin (46.0 (9.8) years). The three groups were matched at baseline for pulse rate, diastolic and systolic blood pressure, and intraocular pressure (IOP). At a single visit, the ocular blood flow analyser (OBFA; Paradigm Medical Instruments Inc, UT, USA) was used to measure pulsatile ocular blood flow (POBF) and pulse amplitude (PA) in each eye of all subjects. One way ANCOVA (with age as a covariate) was used to identify differences in POBF and PA between the groups. For the vigabatrin group only, Pearson's product moment correlation coefficient was used to explore potential interactions between ocular blood flow parameters and cumulative vigabatrin dose, duration, and maximum dose. RESULTS: Both the vigabatrin treated epilepsy group and conventionally treated epilepsy group exhibited significantly reduced POBF (p=<0.001, p=0.040) and PA (p=<0.001, p=0.005) compared to normal subjects. Patients treated with vigabatrin exhibited a further reduction in POBF (p=0.046) and PA (p=0.034) compared to conventionally treated epilepsy patients. No significant correlations were found between drug dosage and POBF and PA for the vigabatrin treated epilepsy group. CONCLUSIONS: A significant reduction in POBF and PA is apparent in epilepsy patients treated with AEDs when compared to normal subjects. A further reduction in POBF and PA is apparent between vigabatrin treated and conventionally treated patients. The reduction in ocular perfusion, which is more pronounced in patients previously treated with vigabatrin, may have implications in the impairment of visual function associated with the drug.

Effect of senescence on ocular blood flow in the retina, neuroretinal rim and lamina cribrosa, using scanning laser Doppler flowmetry.

PURPOSE: To determine the effects of age on blood flow measurements obtained using the scanning laser Doppler flowmeter (SLDF). METHOD: Using SLDF (Heidelberg retina flowmeter, Heidelberg Engineering, Germany) three 10 degrees images were taken of the superior temporal retina and three further images of the superior temporal neuroretinal rim in 15 young, healthy subjects (mean age 27.9 years +/- 6.2 years) and 15 mature, healthy subjects (mean age 65.2 years +/- 13.7 years). In addition, measurements were taken of the lamina cribrosa in 12 of the volunteers from each subject group (mean age 27.1 +/- 6.3 years and 64.8 +/- 13.2 years respectively). Using a 10 x 10 pixel measurement frame, blood flow readings were obtained at a predetermined position on the retina, neuroretinal rim and lamina cribrosa. Student's two-tailed unpaired t-tests were used to compare measures of blood flow, volume and velocity between the two subject groups (P < 0.05). In addition, linear regression analysis was used to assess the relationship between age and blood flow, volume and velocity at the retina, neuroretinal rim and lamina cribrosa. RESULTS: Retinal blood volume measured at the retina was significantly lower in the mature compared with the young subject group (P = 0.01). Mature subjects also exhibited reduced blood flow and velocity at the neuroretinal rim (P = 0.01 for both parameters) and lamina cribrosa (P = 0.008 and P = 0.01 respectively). Regression analysis revealed negative trends for all blood flow parameters in each of the anatomical areas with advancing age. Significant negative correlations were obtained for retinal blood volume (r = -0.455, P < 0.05), neuroretinal rim blood velocity (r = -0.359, P < 0.05) and lamina cribrosa blood volume (r = -0.475, P < 0.05). CONCLUSION: Capillary blood flow in the retina, neuroretinal rim and lamina cribrosa decreases with advancing age. This may be of consequence in the progression of chronic ocular diseases such as glaucoma, and should be considered in the longitudinal determination of change in disease monitoring.