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S L Bennett

Publications and source records attributed to S L Bennett.

12 recordsLinked to original sources
PubMed1996

Effects of electrode montage on the spectral composition of the infant auditory brainstem response.

We evaluated the effect of electrode montage on the spectrum of the infant auditory brainstem response (ABR). Spectral profiles of ipsilateral, contralateral, noncephalic, and horizontal recordings obtained in response to slow and fast repetition rates and at low and high stimulus intensities were also evaluated. Findings indicate that the spectrum of the infant ABR is dominated by low-frequency energy, maximal below 200 Hz. The spectra of ipsilateral and noncephalic recordings are the strongest irrespective of stimulus intensity or repetition rate. Increase in stimulus intensity or repetition rate typically enhances the amount of energy below 200 Hz. These results reinforce the clinical utility of ipsilateral and noncephalic recordings for screening, threshold measurement, and neurodiagnostic purposes.

Adult↗
PubMed1995

Effects of electrode montage on infant auditory brainstem response.

The present study compares ipsilateral, contralateral, horizontal and non-cephalic auditory-evoked brainstem responses (ABR) obtained from normal infants (39-42 weeks' post-conceptional age) to assess their utility in auditory neurodiagnosis. Wave latencies, wave amplitudes and waveform morphology were evaluated at slow and fast repetition rates. Ipsilateral and horizontal recordings obtained with a fast stimulation rate provide best waveform characteristics for neurodiagnostic interpretation. Further enhancement of wave V amplitude and separation of IV-V wave complex may be achieved by using the non-cephalic recording montage. Compromised or low amplitude components on contralateral measurements may confound neurological interpretation.

Electrodes↗
PubMed1993

The ferning and nitrazine tests of amniotic fluid between 12 and 41 weeks gestation.

Most studies investigating the usefulness of ferning and nitrazine methods for detecting the presence of amniotic fluid following ruptured amniotic membranes have employed samples from vaginal pooling. Reported accuracies are 84 to 100% for the ferning test and 87 to 97% for the nitrazine test. Our study was designed to determine if these tests are applicable throughout gestation. Samples were obtained from amniocenteses between 14 and 42 weeks. Part I: Of 112 samples allowed to dry on a slide for 3 minutes only, 86.6% were ferning positive and 100% were nitrazine positive. Flame-drying increased the presence of ferning to 96.4%. Part II: 363 samples were allowed to dry completely for up to 10 minutes. All samples were ferning and nitrazine positive. Part III: 17 samples were tested for ferning and nitrazine at 1 hour, and again at 1 week. Sixty-six samples were tested within 1 week and again at 2 weeks. All samples remained ferning and nitrazine positive. Therefore optimal analysis of suspected amniotic fluid occurs when specimens are air-dried for 10 minutes. These tests may be reliably performed at gestations of 12 to 41 weeks.

Amniotic Fluid↗
PubMed1992

Case report: survival of an infant with a birthweight of 345 grams.

Infant survival with ever-decreasing birthweights is attainable with recent advances in maternal-fetal medicine and enhanced neonatal intensive care. We report a gestation complicated by severe chronic hypertension and fetal distress necessitating delivery at 26 1/7 weeks. The growth-retarded newborn weighted 345 g (12 oz) and survived with minimal sequelae despite a protracted and complicated neonatal course.

Adult↗
PubMed1987

Effect of penetration enhancers on the permeation of mannitol, hydrocortisone and progesterone through human skin.

Mannitol, hydrocortisone and progesterone were selected as model penetrants to assess the mode of action of eight potential penetration enhancers in human skin. Their partition coefficients, octanol: water and stratum corneum: water were measured and correlated with their postulated routes of penetration through human skin. The results suggest that mannitol penetrated via a polar route, hydrocortisone by a mainly lipid route and progesterone via a lipid pathway but its penetration rate was probably affected by aqueous layers. From permeation studies through cadaver skin in which an in-vivo mimic method was used, it was concluded that the penetration enhancers fell into three main categories: solvents which enhanced permeation of polar and non-polar compounds e.g. 2-pyrrolidone, N-methylpyrrolidone, N-methylformamide and propylene glycol plus Azone; enhancers which preferentially affected the polar route e.g. propylene glycol plus decylmethylsulphoxide, and accelerants which mainly modified the non-polar route e.g. propylene glycol plus oleic acid, propylene glycol alone and, to a limited extent, water.

Acetone↗
PubMed1985

Optimization of bioavailability of topical steroids: non-occluded penetration enhancers under thermodynamic control.

The non-occluded vasoconstrictor test under thermodynamic control assessed the effect of penetration enhancers on the topical bioavailability of a model steroid betamethasone 17-benzoate, using aqueous dimethylisosorbide (DMI) as a standard solvent. The aqueous potential penetration enhancers used were at 10% steroid saturation i.e. ideally at identical steroid thermodynamic activity. In the vasoconstrictor test, 2-pyrrolidone, N-methyl-2-pyrrolidone, propylene glycol with oleic acid, propylene glycol with azone and dimethylformamide (DMF) increased the steroid bioavailability compared with that from DMI, while propylene glycol alone produced borderline improvement. Azone and oleic acid in combination with DMI or Betnovate cream did not increase the steroid bioavailability indicating the importance of the correct cosolvent. The pyrrolidones established superior stratum corneum reservoirs compared with DMI, the other vehicles being similar to DMI. It was concluded that excepting DMI, the solvents tested were penetration enhancers for the model steroid betamethasone 17-benzoate and are worthy of further study. However, irritant effects may make some of them unacceptable for clinical use.

Administration, Topical↗
PubMed1980

Early emotion.

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Adult↗