Electroporation as an effective means of introducing DNA into abalone (Haliotis rufescens) embryos.

Recombinant plasmid containing the Drosophila beta-actin promoter coupled to a beta-galactosidase cassette was linearized and introduced in fertilized eggs of the red abalone (Haliotis rufescens) by electroporation. Fertilized abalone eggs tolerated electroporation well with larval survival rates between 70% and 84% of that for non-electroporated siblings. Dot blot and Southern blot analysis were used to detect if abalone retained the foreign gene at various developmental stages. The inserted construct was retained in 70% to 100% of all abalone sampled with an average of 72% retention in the three- to seven-month-old juveniles. Maximal DNA uptake and retention was observed in abalone electroporated at 30-40 min after fertilization. Southern hybridization analysis suggested that the inserted vector was in head-to-tail concantermers integrated in the abalone genome. This preliminary study demonstrates that electroporation is an efficient means of transferring foreign DNA into abalone embryos.

Multifocal intraocular lenses and glare.

In a previous paper, we reported finding deficits in the contrast sensitivity functions of patients with diffractive multifocal intraocular lenses (IOL's). The results were consistent with optical measurements of the modulation transfer function (MTF) of the IOL. When this MTF is treated as a linear spatial frequency filter, it predicts the existence of a glare effect; contrast threshold for the recognition of target letters should be elevated by a bright, adjacent stimulus. We tested this prediction by measuring contrast thresholds for recognizing 0.2 degrees Sloan letters on a background luminance of 11.2 cd/m2. The letters were presented inside bright (300 cd/m2) annular rings with inner diameters ranging from 0.42 to 1.22 degrees. Thresholds were measured for seven multifocal subjects, age-matched groups of monofocal subjects and phakic-control subjects, and a young group. Multifocal subjects exhibited a greater glare effect than monofocal subjects, and they in turn exhibited a greater effect than phakic-control subjects. The observed glare effect for multifocal subjects was about twice that expected from the spatial filtering property of the multifocal IOL.

Contrast sensitivity and reading through multifocal intraocular lenses.

Multifocal intraocular lenses are intended to increase depth of focus for patients with cataracts, but optical considerations predict reduced retinal-image contrast. We evaluated visual performance through multifocal intraocular lenses by measuring contrast sensitivity functions and reading speed for age-matched groups with multifocal and monofocal intraocular lenses and two normal control groups. Contrast sensitivity functions of the patients with multifocal lenses did not differ significantly for optical distances differing by 2.5 diopters, indicating substantial depth of focus. Normal and monofocal contrast sensitivity functions were nearly identical, and both were about a factor of two higher than multifocal contrast sensitivity functions. Patients with multifocal lenses showed deficits in reading speed only for low-contrast text (less than 30%) and small letters (0.2 degree and 1.0 degree).

Effects of standard anticoagulants and storage procedures on plasma glucose values in seals.

Standard methods for the preservation of vertebrate blood samples for glucose analysis include collecting and storing the blood in evacuated tubes containing sodium fluoride (glycolytic inhibitor) and potassium oxalate (anticoagulant). We found that blood collected from 5 seals by venipuncture and transferred into these tubes had a significantly (P less than 0.05) lower plasma glucose value than blood transferred into tubes containing heparin. In species in which RBC glucose concentration is significantly less than that in the plasma, fluoride and oxalate-induced hemolysis dilutes the plasma with cytoplasm and lowers the measured concentration of glucose in plasma. Therefore, although plasma glucose is used extensively in experimental and clinical analyses, standard techniques for handling the blood may create errors that could confuse comparisons between individuals or species.

Professional nursing roles. The reintegration of patient teaching.

This article stresses the critical nature of the education function of the nurse and suggests strategies for reintegrating teaching as a professional role. It is important that administrators value teaching and that staff development departments assist nurses in refining teaching skills.

Speech waveform envelope cues for consonant recognition.

This study investigated the cues for consonant recognition that are available in the time-intensity envelope of speech. Twelve normal-hearing subjects listened to three sets of spectrally identical noise stimuli created by multiplying noise with the speech envelopes of 19(aCa) natural-speech nonsense syllables. The speech envelope for each of the three noise conditions was derived using a different low-pass filter cutoff (20, 200, and 2000 Hz). Average consonant identification performance was above chance for the three noise conditions and improved significantly with the increase in envelope bandwidth from 20-200 Hz. SINDSCAL multidimensional scaling analysis of the consonant confusions data identified three speech envelope features that divided the 19 consonants into four envelope feature groups ("envemes"). The enveme groups in combination with visually distinctive speech feature groupings ("visemes") can distinguish most of the 19 consonants. These results suggest that near-perfect consonant identification performance could be attained by subjects who receive only enveme and viseme information and no spectral information.

Progesterone and estrogens in the pregnant and nonpregnant dolphin, Tursiops truncatus, and the effects of induced ovulation.

Baseline serum levels of progesterone and total immunoreactive estrogens were determined for intact and ovariectomized captive female Atlantic bottlenose dolphins (Tursiops truncatus), as well as newly captured wild adult females. Stimulation of ovarian follicular growth and ovulation was attempted by intramuscular injection of pregnant mare's serum gonadotropin (PMSG). High doses of PMSG were required to increase serum estrogen levels. When PMSG was followed by an injection of human chorionic gonadotropin (hCG), ovulation was presumed to have occurred as indicated by subsequent high levels of serum progesterone. From these observations, it appears that 1) females with progesterone levels greater than 3000 pg/ml over an extended period are pregnant, 2) Tursiops truncatus is capable of spontaneous ovulation in captivity without gonadotropin therapy, 3) captive female dolphins, although relatively resistant to PMSG, can be induced to ovulate using a combination of high intramuscular-injected doses of PMSG followed by hCG, and 4) spontaneous ovulation is likely to follow an induced ovulation.