Skin lightening creams containing hydroquinone.
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Dermatologic Agents↗
Biomedical subjects
H Williams
Publications and source records attributed to H Williams.
Hemispheric differences in avian song discrimination.
Auditory input to the right or left forebrain of adult male zebra finches (Taeniopygia guttata) was disrupted by lesioning the ipsilateral auditory relay nucleus of the thalamus. These birds were then presented with two kinds of auditory discriminations: (i) between their own song and the song of a cage mate; (ii) between two versions of an unfamiliar zebra finch song that differed only in the harmonic profile of one of the syllables. Right-side lesion birds did better than left-side lesion ones at discriminating between their own song and the song of a cage mate; left-side lesion birds did better on the harmonic profile task. We suggest that the two halves of the zebra finch brain process conspecific sounds differently, as seems to be the case for humans.
Animals↗
Right-side dominance for song control in the zebra finch.
Adult male zebra finches underwent unilateral denervation of the syrinx or unilateral lesion of the forebrain nucleus HVC known to be important for song control. Disruptive effects on song were greater after right-side than after left-side operations. After denervation of the right half of the syrinx, the fundamental frequencies of all syllables within a song converged on a value near 500 Hz, and nearly all syllables were altered in type. In contrast, the syllables produced after denervation of the left side of the syrinx largely maintained their preoperative frequencies, and fewer syllables changed in type. Unlike nerve sections, HVC lesions did not result in strikingly lateralized effects on syllable phonology; however, HVC lesions did affect the temporal patterning of a bird's song, whereas nerve sections did not, and changes in temporal patterning were more marked after right than after left HVC lesions. Right-side dominance for zebra finch song control is the reverse of that described in other songbird species with lateral asymmetry for vocal communication. We suggest that the need for a dominant side is more important than the side of dominance.
Anesthesia↗
Yohimbine reduces neuropathology induced by ketamine/xylazine anesthesia.
Ketamine, an NMDA receptor antagonist, is commonly used in combination with xylazine, an alpha 2-adrenergic receptor agonist, to induce surgical anesthesia in birds and other vertebrates. Problems associated with this anesthetic combination include impaired thermoregulation, compounded by the inability to feed while anesthesia lasts (approximately 6 h after a single dose), and the ketamine-induced vacuolization of large cortical neurons. In the zebra finch, yohimbine (an alpha 2-adrenergic receptor agonist) counters the effects of ketamine/xylazine anesthesia, speeding recovery after the surgical procedure has been completed. In addition, administration of yohimbine reduces the formation of vacuoles in large cortical neurons and in neuropil. Yohimbine administration should be considered following all procedures involving ketamine/xylazine anesthesia.
Anesthesia, General↗
Clinical procedures review: another casualty of a litigious society.
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California↗
Changes in stereotyped central motor patterns controlling vocalization are induced by peripheral nerve injury.
Adult male zebra finches (Taeniopygia guttata), as closed-ended learners, normally crystallize their songs at 90 days of age, and the song remains fixed throughout life (Price, 1979). We show that injuring the tracheosyringeal nerve(s) (each of which innervates the ipsilateral half of the syrinx, the avian vocal organ) results in a short-term deficit in the syllables forming adult male song; this deficit disappears after ts nerve regeneration. However, when adult males were followed for a period of several weeks after unilateral tracheosyringeal nerve injury, long-term changes occurred in the temporal patterning of song. Syllables were deleted, remaining portions of the song were linked, and new syllables were added. Syllables with call-like morphology were less likely to be deleted from and more likely to be added to the song. Deletions were most often contiguous chunks of syllables. Changes in the temporal patterning of song occurred during specific periods following nerve injury, were completed within 100 days after nerve transection, and were not dependent upon regeneration of the ts nerve. The resulting newly formed song patterns were stable, remaining unchanged up to 1 year later. The ability of adult male zebra finches to make specific types of changes to crystallized song indicates that some form of vocal plasticity remains even after song learning is completed, though this plasticity may be restricted to a subset of song characteristics. The limitations on the types of changes that are possible may reflect how song is centrally organized.
Animal Communication↗
Human immunodeficiency virus infection among inner-city adolescent parturients undergoing routine voluntary screening, July 1987 to March 1991.
OBJECTIVE: The objective of our study was to describe the human immunodeficiency virus epidemic among pregnant adolescents undergoing follow-up in a large inner-city hospital. STUDY DESIGN: We conducted a case-control study comparing demographic and risk behaviors of seropositive and seronegative adolescents (aged 13 to 20) identified from a population undergoing routine voluntary antibody screening at Grady Memorial Hospital in Atlanta, Georgia, between July 1987 and March 1991. RESULTS: Of 10,794 pregnant adolescents screened, 51 (4.7/1000) were infected with human immunodeficiency virus. More than one fourth of case patients were < or = 17 years old. Significantly more case patients than controls reported a history of crack cocaine use (10 [19.6%] vs 23 [8.2%] p < 0.05). A majority (58.8%) of case patients reported no risk factors for infection, and the remainder (41.2%) were presumably infected by heterosexual contact. Thirty-nine controls (13.8%) had self-identified risk factors for infection. CONCLUSIONS: Pregnant adolescents in our center are at risk for human immunodeficiency virus infection and should be targeted for human immunodeficiency virus education and risk reduction counseling.
Adolescent↗
Syllable chunking in zebra finch (Taeniopygia guttata) song.
We examined how 61 young zebra finch (Taeniopygia guttata) males copied song from 5 adult tutors. Zebra finch song consists of a string of 5-15 distinct syllables, and these syllables were copied as chunks, or strings of consecutive syllables (modal length = 3). The silent interval between 2 syllables was copied as part of the syllable after the silence. Copied chunks had boundaries that fell at consistent locations within the tutor's song, marked by a relatively long intersyllable silent period, a transition between call-like and noncall-like syllables, and a tendency for the tutor male to stop his song short. Young males also tended to break their songs off at the boundaries of the chunks they had copied. Chunks appear to be an intermediate level of hierarchy in song organization and to have both perceptual (syllables were learned as part of a chunk) and motor (song delivery was broken almost exclusively at chunk boundaries) aspects.
Animals↗
Evaluation of changes in myocardial function on exercise in patients with coronary artery disease using gated MIBI scintigraphy.
Technetium-99m-methoxy-isobutyl-isonitrile (MIBI) is a myocardial perfusion agent which allows simultaneous assessment of left ventricular function. We evaluated left ventricular (LV) function with exercise using a new method of myocardial profiling in 43 patients with chest pain. Twenty-eight had significant coronary artery disease and 15 were normal on coronary angiography. Results were compared to equilibrium radionuclide ventriculography. MIBI fractional shortening (FS) correlated well with ejection fraction (EF) on exercise (r = 0.79, P = less than 0.001). There was also a good correlation between changes in global function from rest to exercise (r = 0.82, P = less than 0.001) with a sensitivity of diagnosing CAD of 71% and specificity of 80%. New regional wall abnormalities were detected in 25/28 with CAD with a sensitivity of 89% and specificity of 60%. There was also a close correlation between mean diameters measured with gated MIBI scans and volumes measured with RNV, end-diastolic diameter (EDD) versus end-diastolic volume (EDV) r = 0.78 (P = less than 0.001) at rest and r = 0.74 (P = less than 0.001) on exercise and end-systolic diameter (ESD) versus end-systolic volume (ESV) r = 0.72 (P = less than 0.001) at rest and r = 0.72 (P = less than 0.001) on exercise. This produced a sensitivity for detecting CAD of 79% and a specificity of 73%. These results show that gated MIBI scanning on exercise provides information comparable to RNV so enhancing the diagnostic usefulness of MIBI.
Adult↗
Evaluation of the Alvarado score in acute appendicitis.
Use of the Alvarado scoring system was assessed prospectively in a consecutive series of 215 patients with suspected appendicitis over a 12 month period at the University Hospital of Wales, Cardiff. In comparison the high negative appendicectomy rate during the year prior to the study was reduced considerably with the scoring system without increasing morbidity or mortality.
Adult↗
Linear scleroderma and melorheostosis.
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Aged↗
Diastereotopic covalent binding of the natural inhibitor leupeptin to trypsin: detection of two interconverting hemiacetals by solution and solid-state NMR spectroscopy.
The naturally occurring peptidyl protease inhibitor leupeptin (N-acetyl-L-leucyl-L-leucyl-L-argininal) has been prepared labeled with 13C at the argininal carbonyl. 13C chemical shift data for the trypsin-leupeptin inhibitor complex in the pH range 3.0-7.6 reveal the presence of two pH-dependent covalent complexes, suggestive of two interconverting diastereomers at the new asymmetric tetrahedral center created by covalent addition of Ser195 to either side of the 13C-enriched aldehyde of the inhibitor. At pH 7 two signals are observable at delta 98.8 and delta 97.2 (84:16 ratio), while at pH 3.0 the latter signal predominates. In the selective proton 13C-edited NOE spectrum of the major diastereomer at pH 7.4, a strong NOE is observed between the hemiacetal proton of the inhibitor and the C2 proton of His57 of the enzyme, thus defining the stereochemistry of the high pH complex to the S configuration in which the hemiacetal oxygen resides in the oxyanion hole. pH titration studies further indicate that the 13C chemical shift of the S diastereomer follows a titration curve with a pKa of 4.69, the magnitude of which is consistent with direct titration of the hemiacetal oxygen. Similar pH-dependent chemical shifts were obtained by using CPMAS 13C NMR, providing evidence for the existence of the same diastereomeric equilibrium in the solid state.
Binding Sites↗
Incidence and prevalence of human immunodeficiency virus infection in a prenatal population undergoing routine voluntary human immunodeficiency virus screening, July 1987 to June 1990.
To characterize the epidemiologic characteristics of human immunodeficiency virus type 1 infection in an urban prenatal population in the southeastern United States, we conducted serial routine voluntary antenatal human immunodeficiency virus antibody testing and obtained self-reported human immunodeficiency virus risk behavior profiles on women registering for prenatal care. From July 1987 to June 1990, 23,432 women registered for prenatal care. The majority of women (95%) consented to human immunodeficiency virus antibody testing and completed risk behavior profiles. The cumulative incidence of human immunodeficiency virus infection increased from 3.5 per 1000 in 1987 and 1988 to 5.3 per 1000 in 1989 and 1990. A history of "crack" cocaine use emerged as a significant risk factor for infection (p less than 0.01). The majority (70%) of human immunodeficiency virus-infected women did not self-acknowledge risk factors for infection and would not have been identified if screening had been targeted. The increasing incidence of human immunodeficiency virus type 1 infection in our prenatal population reinforces the need for our continued routine voluntary antenatal human immunodeficiency virus screening and risk behavior assessment.
Acquired Immunodeficiency Syndrome↗
Louping ill in man: a forgotten disease.
Louping ill disease of sheep has been recognised in Scotland for centuries. It causes encephalitis and is transmitted by the sheep tick, Ixodes ricinus. Human infection was first reported in 1934. Thirty-one cases of human infection have now been described. Four clinical syndromes are seen, an influenza-like illness, a bi-phase encephalitis, a poliomyelitis-like illness and a hemorrhagic fever. Certain occupational groups, e.g. laboratory personnel working with the virus and those who kill injected sheep, are at increased risk of acquiring louping ill infection. In many instances, infection is subclinical. Eight new human cases are described. Six were in crofters or shepherds in the north and west of Scotland, one was in a general practitioner in the Western Isles and the eighth was in a butcher in Edinburgh. Louping ill disease should not be forgotten in cases of unexplained encephalitis in those whose lifestyle exposes them to the virus.
Animals↗
Gated 99Tcm-MIBI myocardial function imaging.
The introduction of the 99Tcm isonitrile perfusion agents has provided improved myocardial image quality with conventional imaging equipment allowing improved edge definition on gating. We evaluated left ventricular wall motion in 46 patients using gated 99Tcm-2-methoxy-2-methyl-isopropyl-1-isonitrile (MIBI) scintigraphy. Using a method of myocardial profiles in four axes, global and regional fractional shortening (FS) were assessed. A good correlation was found between FS in the left anterior oblique (LAO) 40 degrees projection and ejection fraction (EF) on gated radionuclide ventriculography (r = 0.81, P less than 0.001). This was improved by using FS in two planes, LAO 40 degrees and anterior (r = 0.88, P less than 0.001). There was also a good correlation between FS in two planes and EF on cine-angiography (r = 0.72, P less than 0.001). There was good intra- and interobserver agreement with the studies. Assessment of myocardial function using gated MIBI imaging and myocardial profiles provides useful additional information to the perfusion scan, thus enhancing the diagnostic usefulness of the agent.
Adult↗
Depression in mothers and behaviour problems with their preschool children.
A follow-up study of 224 families of a birth cohort of 272 families in a multi-ethnic poor socio-economic municipality in Melbourne when the children were 4 years old showed that 27% of the mothers were depressed. There was no difference in the depression rate between Australian-born and immigrant mothers, a finding in marked contrast to the first year of the study when the depression rate was significantly higher in those immigrant mothers who had been in Australia for less than 3 years, were unable to speak English and who did not have an extended family or close friends. Depression in this group of mothers was attributed to resettlement problems, which over a period of three years had ameliorated. At 4 years the most important factor associated with depression in both Australian-born and immigrant mothers was the quality of marital relationships. Lack of an intimate support relationship made mothers more vulnerable to the stresses of child care and rearing, home-making and life events. In Australian-born mothers only, another significant factor in vulnerability to depression, was their early childhood experiences of being reared in a disruptive home or in an institution and of being unwanted. In immigrant mothers, but not in Australian-born mothers, life events were significantly correlated with depression. The depressed mothers, both Australian-born and immigrant, perceived their 4 year old children to have significantly more behavioural problems than mothers who were not depressed.
Analysis of Variance↗
Direct assay of A alpha(1-21), a PMN elastase-specific cleavage product of fibrinogen, in the chimpanzee.
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Animals↗
Clinical and microbiological investigations of anorexia nervosa.
Several studies have examined the relationship between anorexia nervosa and oral status. However, none has used control subjects. Furthermore, none has examined bacteriological data in these subjects to determine whether dietary restrictions, particularly of carbohydrates, change the levels of Streptococcus mutans and Lactobacillus species. Fifteen female subjects recently hospitalized for anorexia were studied along with fifteen age- and sex-matched control subjects. The parameters examined included salivary pH and flow rate, levels of S. mutans and Lactobacillus spp., DMFT scores, facial and palatal plaque scores, periodontal pocketing, gingival recession and bleeding following gentle probing. Compared with control subjects, anorexics had significantly lower salivary pH (7.1 +/- 0.4 vs 7.6 +/- 0.3, p less than 0.01), more facial and lingual surfaces with plaque scores of 1 (facial plaque 38 per cent vs 18 per cent, p less than 0.01, lingual plaque 47 per cent vs 29 per cent, p less than 0.01), more surfaces with gingival recession (1 mm-7.9 per cent vs 1.8 per cent, p less than 0.001; 2 mm-1.7 per cent vs 0.2 per cent, p less than 0.001; greater than 2 mm-0.6 per cent vs 0.0 per cent, p less than 0.001), more surfaces with bleeding on probing (16.9 per cent vs 6.5 per cent, p less than 0.001) and fewer sextants with CPITN scores of 0 (1.9 +/- 1.5 vs 3.2 +/- 1.0, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗