Self-induced plantar-flexion objectively reduces wave amplitude of detrusor overactivity and subjectively improve urinary urgency: a pilot study.

AIMS: To estimate the effect of plantar-flexion on the wave amplitude of involuntary detrusor contraction and the severity of urinary urgency during filling cystometry in patients with detrusor overactivity (DO). METHODS: Twenty-two consecutive patients with DO were enrolled. During urodynamics, the mean peak detrusor pressures of each contraction were documented and compared. At the beginning of the 2nd or 3rd wave, patients were asked to perform continuous plantar-flexion by pushing their tiptoes against the floor. Following each wave, patients were asked to grade the severity of the urgency by a visual analogue scale (VAS). RESULTS: The mean peak detrusor pressure without plantar-flexion was 58 cmH2 O (95% CI: 46.3-69.7) compared to 31 cmH2 O (95% CI: 23.1-38.9) with plantar-flexion (P < 0.001). All patients reported a reduced degree of urgency during plantar-flexion reflected in a significant reduction in mean VAS score from 9.3 (95% CI: 9-9.5) to 4.7 (95% CI: 3.9-5.4; P < 0.0001). CONCLUSIONS: Self-performed plantar-flexion maneuver might reduce the severity of urinary urgency and the magnitude of overactive detrusor contractions, which may have a role in the conservative therapy of detrusor overactivity.

Double branched flicker fusion curves from the all-rod skate retina.

Electrical responses from the skate retina will only follow flicker up to frequencies of 5 hertz when intensities are below rod saturation. At greater luminances, the eye responds to rates as high as 30 hertz. As a result, a plot of critical flicker fusion as a function of intensity is a double branched curve. It seems that prolonged stimulation of skate rods, at high intensities, permits them to change their temporal response characteristics so that they follow high frequencies much as cones do in the duplex retina.

Cytotoxic effects of free fatty acids on ascites tumor cells.

The effect of physiologic common free fatty acids (FFAs) on Mat 1376b ascites tumor cells in vitro and in vivo in F344 rats was investigated. Unsaturated fatty acids, such as palmitoleic (16:1), oleic (18:1), linoleic (18:2), linolenic (18:3), and arachidonic (20:4) acids, were significantly more effective killers of tumor cells in vitro than the corresponding saturated fatty acids of the same carbon length, including palmitic (16:0), stearic (18:0), and arachidic (20:0) acids. The saturated 16-carbon fatty acid (palmitic acid) was more toxic to tumor cells in vitro than the saturated 18-carbon (stearic) and 20-carbon (arachidic) acids. Injections of linoleic (18:2)-linolenic (18:3) acid combinations into rats inoculated with the tumor significantly enhanced the survival of the tumor-bearing animals. These results suggest that natural FFAs may under certain conditions be utilized as effective anticancer agents.

Bicarbonate ion-ATPase in rat liver cell fractions.

The distribution of HCO3MINUS-ATPase activity was studied in cell fractions prepared from homogenates of rat liver. The level of mitochondrial contamination in the microsomal fraction depended on the fractionation procedure and on the method of homogenization. With proper care, microsomes with undetectable mitochondrial contamination could be prepared. These microsomes had no detectable HCO3MINUS-ATPase activity. Approximately 85% of the total HCO3minus-ATPase activity of the post 6000 times g-min supernatant was recovered in the mitochondrial fraction. The properties of this mitochondrial HCO3minus-ATPase were not distinguishable from those of the various microsomal HCO3minus-ATPases previously described by other investigators.

"Rapid regeneration" in the cat retina: a case for spreading depression.

Fundus reflectometry of the cat retina showed that under certain circumstances a rapid increase in density may follow intense bleaching exposures. The spectral characteristics of the density changes indicated that neither rhodopsin nor its bleach products could be responsible for this effect. The poor condition of the animals in which the phenomenon was observed and its conspicuous absence in the majority of the experimental runs suggested that the effect was associated with a process other than the resynthesis of rhodopsin. It was shown that an extrareceptoral event, spreading depression (SD) of the retina, is the most likely source of the rapid spectral change. The well-known tissue alterations associated with SD were induced in the retina independently of pigment density change. The resultant difference spectra resembled those produced when the rapid density increase occurred spontaneously. It seems likely that the abnormal physiological condition of those cats in which the phenomenon is more frequently observed primes the retina for the light-induced generation of spreading depression.

Rhodopsin kinetics in the cat retina.

The bleaching and regeneration of rhodopsin in the living cat retina was studied by means of fundus reflectometry. Bleaching was effected by continuous light exposures of 1 min or 20 min, and the changes in retinal absorbance were measured at 29 wavelengths. For all of the conditions studied (fractional bleaches of from 65 to 100%), the regeneration of rhodopsin to its prebleach levels required greater than 60 min in darkness. After the 1-min exposures, the difference spectra recorded during the first 10 min of dark adaptation were dominated by photoproduct absorption, and rhodopsin regeneration kinetics were obscured by these intermediate processes. Extending the bleaching duration to 20 min gave the products of photolysis an opportunity to dissipate, and it was possible to follow the regenerative process over its full time-course. It was not possible, however, to fit these data with the simple exponential function predicted by first-order reaction kinetics. Other possible mechanisms were considered and are presented in the text. Nevertheless, the kinetics of regeneration compared favorably with the temporal changes in log sensitivity determined electrophysiologically by other investigators. Based on the bleaching curve for cat rhodopsin, the photosensitivity was determined and found to approximate closely the value obtained for human rhodopsin; i.e., the energy Ec required to bleach 1-e-1 of the available rhodopsin was 7.09 log scotopic troland-seconds (corrected for the optics of the cat eye), as compared with approximately 7.0 in man.

Flash photolysis of rhodopsin in the cat retina.

The bleaching of rhodopsin by short-duration flashes of a xenon discharge lamp was studied in vivo in the cat retina with the aid of a rapid, spectral-scan fundus reflectometer. Difference spectra recorded over a broad range of intensities showed that the bleaching efficacy of high-intensity flashes was less than that of longer duration, steady lights delivering the same amount of energy. Both the empirical results and those derived from a theoretical analysis of flash photolysis indicate that, under the conditions of these experiments, the upper limit of the flash bleaching of rhodopsin in cat is approximately 90%. Although the fact that a full bleach could not be attained is attributable to photoreversal, i.e., the photic regeneration of rhodopsin from its light-sensitive intermediates, the 90% limit is considerably higher than the 50% (or lower) value obtained under other experimental circumstances. Thus, it appears that the duration (approximately 1 ms) and spectral composition of the flash, coupled with the kinetic parameters of the thermal and photic reactions in the cat retina, reduce the light-induced regeneration of rhodopsin to approximately 10%.

Retinal mechanisms of visual adaptation in the skate.

Electrical potentials were recorded from different levels within the skate retina. Comparing the adaptive properties of the various responses revealed that the isolated receptor potential and the S-potential always exhibited similar changes in sensitivity, and that the b-wave and ganglion-cell thresholds acted in concert. However, the two sets of responses behaved differently under certain conditions. For example, a dimly iluminated background that had no measurable effect on the senitivities of either of the distal responses, raised significantly the thresholds of both the b-wave and the ganglion cell responses. In addition, the rate of recovery during the early, "neural" phase of dark adaptation was significantly faster for the receptor and S-potentials than for the b-wave or ganglion cell discharge. These results indicate that there is an adaptive ("network") mechanism in the retina which can influence significantly b-wave and gaglion cell activity and which behaves independently of the receptors and horizontal cells. We conclude that visual adaptation in the skate retina is regulated by a combination of receptoral and network mechanisms.

Effect of chemical structure on nonelectrolyte penetration of oral mucosa.

The in vitro permeability of oral mucosa from New Zealand rabbits to 17 nonelectrolytes was studied using radioactive tracer techniques. Calculated permeability coefficients were independent of solute concentration and were similar when measured from outer to inner surface or inner to outer surface. Generally, an increase in chain length and increased lipid solubility within a series of alcohols or diols resulted in increased permeability. However, the first member of each series displayed anomalous behavior in that it penetrated more rapidly than the second member of the series. Addition of one or more hydroxyl groups to a compound brings about a decrease in permeability. The addition of a second or third hydroxyl group has less of an effect in decreasing permeability if it is adjacent to an existing hydroxyl as compared to when it is further separated. Addition of a hydroxyl group to a compound decreases permeability to a greater extent than addition of a ketone. Also, replacement of a hydroxyl group with an amide results in decreased permeability. These results point out the importance of lipid solubility and ability to form hydrogen bonds to permeability.

Foot deformity in myotubular myopathy. Pathology of intrinsic foot musculature.

An intrinsic foot muscle biopsy specimen was taken from a patient with myotubular myopathy who underwent surgical correction for orthopedic deformity. Pathologic findings were typical of primary muscle disease. Foot deformity in myotubular myopathy may result from abnormalities of intrinsic foot muscles, as well as those of more proximal musculature.

Visual system abnormalities in patients with Parkinson's disease.

Visual evoked potentials (VEPs) and contrast sensitivity measurements were determined in normally sighted patients with Parkinson's disease (PD). Prolonged latencies of the first major positive (P100) wave of the VEP elicited by an alternating vertical grating were noted. The delay in latency was positively correlated with the severity of the movement disability. Subjective testing of contrast thresholds demonstrated significant elevation of thresholds in PD. Electroretinographic oscillatory potentials were elicited to determine if the delay in P100 latency was of retinal origin. No specific lesion could be identified to account for the abnormality in VEP or in contrast testing results.

Central nervous system magnetic resonance imaging findings in myotonic dystrophy.

We evaluated findings in 14 patients with myotonic dystrophy (MD) using magnetic resonance imaging of the brain and compared them with those in age-matched controls with headache. There was an increased incidence of ventriculomegaly and a lumpy and/or thick pattern of periventricular hyperintensity in patients with MD as compared with the age-matched controls. These white matter abnormalities do not appear to be etiologically specific, but some possible explanations for these frequent findings in MD are discussed.

Visual evoked potentials in chiasmal gliomas in four adults.

Visual evoked potentials (VEPs) were recorded from four patients with surgically verified chiasmal gliomas. Despite good visual acuity, 6/12(20/40) or better in each eye, these patients showed substantially reduced VEP amplitudes to a diffuse flash stimulus and hardly detectable responses to a highly textured checkerboard-pattern stimulus. The dissociation between evoked electrical activity and visual acuity is noteworthy; this differs from previously reported findings in patients with extrinsic compressing lesions of the chiasm or with lesions of demyelinating disease, which usually reduce VEP amplitude and increase conduction time in rough proportion to a loss of visual acuity.

Reduced contrast sensitivity in compressive lesions of the anterior visual pathway.

A clinical procedure for determining contrast sensitivity was performed on patients with suspected sella area masses. The test consisted of a series of six plates, each containing a bar pattern of fixed sinusoidal spatial frequency in which contrast varies along the length of the bar. Patients with compressive lesions of the chiasm of optic nerve showed loss of contrast sensitivity over the whole range of spatial frequencies. The general loss in contrast was evident even in patients with 20/20 Snellen acuity. After surgery, contrast sensitivity improved, as did other measures of vision, but significant contrast deficits remained. Contrast sensitivity is a sensitive indicator for the diagnosis and evaluation of compressive lesions of the chiasm.

Recording the pattern electroretinogram: a cautionary note.

It is possible to record a pattern electroretinogram (PERG) of near normal amplitude in a situation when the eye containing the active electrode is occluded. Because PERG recording requires high amplification and sensitive signal retrieval techniques, the electrode in the occluded eye records a distant potential from the unoccluded eye. Referencing the active electrode to an ipsilateral ear diminishes, but does not eliminate the referred PERG potential. Such unlooked for interaction may provide misleading data in situations where binocular viewing is used because of poor vision in one eye; therefore, occlusion of the eye not being tested should be undertaken whenever possible.

Functional abnormalities in vincristine-induced night blindness.

Various noninvasive test procedures were used to evaluate retinal function in a patient who had become night blind following vincristine chemotherapy. The results obtained were strikingly similar to those reported previously in subjects with recessively inherited stationary night blindness; the dark-adaptation curve was monophasic (ie, no evidence of a scotopic branch), rhodopsin kinetics were entirely normal, and spectral threshold data revealed the presence of residual rod-mediated vision. Also like the heritable condition, the b-wave of the ERG was depressed grossly despite normal a-wave potentials. These findings, and the fact that vincristine is known to disrupt the structural integrity of neuronal microtubules, suggest that the drug-induced defect involves the process of synaptic transmission between the photoreceptors and their second-order neurons.

Evaluating macular function using the focal ERG.

A stimulus consisting of 96 red LEDs mounted in the rear of a ganzfeld bowl was used to elicit focal electroretinograms (FERG) from the central 9 degrees of the retina in human subjects. The luminance of the stimulus was driven sinusoidally at frequencies from 10-60 Hz. The temporal responsiveness and response phase lags of normal subjects and patients with retinal disease were measured. Normal subjects produced maximum amplitude FERG responses to stimuli between 30-40 Hz. Patients with retinitis pigmentosa showed a low-pass pattern of amplitude loss, with an additional frequency independent loss in sensitivity in those with poorer visual acuity. Patients with macular degeneration showed general amplitude loss associated with a relative sparing of the mid-temporal frequencies. The response phase lags in both patient groups were not significantly different from the normals. These findings point to a loss in temporal responsiveness accompanied by a secondary loss of sensitivity in these heredoretinal degenerations.

Retinitis pigmentosa: a psychophysical test of explanations for early foveal sensitivity loss.

A psychophysical procedure, the probe-flash paradigm, was used to test explanations of early foveal sensitivity loss in retinitis pigmentosa. The findings suggest that this loss may be due to a decreased responsiveness of retinal elements and not to a decrease in quantum catching ability of functioning photoreceptors.

A gold foil electrode: extending the horizons for clinical electroretinography.

A gold foil ERG electrode is described. The device is inexpensive and simple to fabricate. Since it is hooked over the lower lid and makes minimal touch contact with the inferior limbal area, it can be used in circumstances which require prolonged testing of retinal function or in eyes with corneal pathology. Because the optics of the eye are not compromised, it is possible, with the use of appropriate stimuli and response-averaging techniques, to record local EFGs from relatively small retinal areas.

Pigmentary abnormalities of the macula in rhesus monkeys: clinical observations.

In a survey of 546 rhesus monkeys of various ages, 6.1% of the animals showed ophthalmoscopically visible hypopigmented spots in their maculas. There was a statistically significant correlation between the age of the animal and the degree of hypopigmentation. Electroretinographic responses and visually evoked potentials were evaluated in a selected group of monkeys with and without hypopigmented macular spots. No significant change in retinal function as a result of the macular abnormalities could be detected.