Biomedical subjects
Publications and source records attributed to M Petersen.
No significant differences in proficiency of reading-listening comprehension among 24 reading-disabled boys in Grades 4, 5, and 6 were noted after hearing "talking book," taped stories, and teacher-read presentations.
The tympanal organ of the migratory locust acquires its definitive form during larval development. All the receptor cells (90-100) are present in the 1st instar, whereas the differentiation of the tympanum and the cuticular structures it bears proceeds in steps from one instar to the next. The elevated process is the earliest such structure to appear (2nd instar); it is followed by the pyriform vesicle (3rd instar) and folded body (4th instar). The styliform body first appears in the imago. Although the typical arrangement of the receptor cells is already discernible in the 1st instar, some of the attachment sites change during development, the final configuration appearing only in the imago.
Thirty-four members of a single family were studied and 9 of them were found to be suffering from hyperthyroidism associated with diffuse goitre. Exophthalmos was absent and transmission seemed to be independent of HLA type. Four of the 9 were studied prior to treatment but in all cases serum immunoglobulin levels were normal, antithyroglobulin and antimicrosomal antibodies absent, thyroid stimulating antibodies negative and the lymphocyte transformation responses to mitogens not different from those of controls. The results of testing the euthyroid family members were similarly negative, except in the case of a woman with type I diabetes mellitus who showed a low titre of antimicrosomal antibody. Seven of the patients underwent subtotal thyroidectomy. Lymphocytic infiltration of the excised portion was rarely present. Four of the glands were subjected to immunofluorescent and electron microscopy but neither immunosecreting cells nor immune complex deposits were found. These results point to the existence of a non-autoimmune form of goitrous hyperthyroidism, different from Graves' disease.
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A large-scale longitudinal study of working coal miners is analyzed to determine biases due to studying only working miners and only volunteers. Reports of symptoms, pulmonary function indices, and chest radiographs were obtained from the first round of the study and comparisons were made of the rates and means among those who participated in the second round, those who had left the industry before the second round, and those who simply did not participate in the second round. Biases were present in nearly all variables studied, but the biases were fairly small.
Orbital involvement is a rare complication of myeloma usually presenting as unilateral proptosis without pain. A case is reported of a woman with bilateral orbital infiltration without proptosis, who became blind within three months of the onset diplopia. The blindness was due to visual field obstruction, with eyelids covering both corneas; the eyes themselves remained normal. This is the first case of orbital myeloma reported in Australia and only the second case of bilateral primary orbital infiltration with myelomatosis to be reported in the world literature.
There is a steady and nonlinear relationship between the levels of both phenylpyruvic acid (PPA) and o-hydroxyphenylacetic acid (oOPAA) in urine and the plasma levels of phenylalanine (phe) in children more than two years of age with phenylketonuria (PKU). If phe levels in blood rise above 0.35 mM (5.8 mg/100 ml) both aromatic acids are found regularly in urine. Typically, urinary concentrations of PPA are about 5 times higher than those of oOPAA. This report is based on the analysis of 94 samples from 51 children, on or off diet.
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Two patients with dermal necrosis due to anticoagulation therapy with warfarin are reported. Both patients demonstrated some disturbance in immunological function. It appears possible that warfarin may act as a hapten in the induction of hypersensitivity to the drug. It is recommended that future cases should be studied to determine whether there is a defect in immunoregulation, and whether circulating immune complexes are responsible for the typical skin lesions.
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As an extension of earlier work on aliphatic alpha-keto acids, a method is described for the quantitative gas chromatographic determination of urinary aromatic alpha-keto acids. The keto acids are derivatized with o-phenylenediamine to yield the quinoxalinols. These compounds are chromatographed after trimethylsilylation. The aromatic keto acids are stabilized by sodium dithionite (4 mg/ml urine) and storage below 0 degrees. The final derivatives are stable for weeks at room temperature. Low resolution mass spectra are reported. The fragmentation mechanisms are elucidated by analysis of O-trimethylsilyl-(TMS)-quinoxalinois, O-(TMS-d9)-quinoxalinois and O-TMS-6(7)-chloroquinoxalinois.
This paper is the first in a series which extends introductory studies of parinaric acid and its phospholipid derivatives as membrane probes (Sklar, L.A., Hudson, B., and Simoni, R.D. (1975), Proc. Natl. Acad. Sci. after U.S.A. 72, 1649; (1976), J. Supramol. Struct. 4, 449). Parinaric acid has a conjugated tetraene chromophore and exhibits many spectroscopic properties common to linear polyenes. Its absorption spectrum is characterized by a strong near-ultraviolet transition with vibronic structure, which is strongly affected by solvent polarizability. The fluorescence emission occurs at considerably lower energy than the absorption and the wavelength of the emission is nearly independent of the solvent. The fluorescence quantum yield and lifetime are strongly affected by temperature and solvent. These spectral features are interpreted in terms of an excited electronic-state order such that a weak transition occurs at longer wavelengths than the strongly allowed transition which dominates the absorption. The sensitivity of the fluorescence quantum yield an lifetime to environment is shown to be due primarily to variations in the nonradiative rate, although changes in the radiative rate constant are also observed and interpreted. The absorption spectrum (epsilon max greater than 65 000) is in the 300-320-nm range, a region relatively free of absorption due to intrinsic biological chromophores. Shifts of several nanometers are characteristic of different environments. These shifts are compared to similar effects observed for a series of diphenylpolyenes for which new data are given and are correlated using a simple but adequate theory of solvent shifts. The intrinsic (or radiative) fluorescence lifetime is near 100 ns in a wide variety of environments. This is much longer than the intrinsic lifetime calculated from the absorption spectrum and strongly supports the proposed excited-state order.
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