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Biomedical subjects

D O Robinson

Publications and source records attributed to D O Robinson.

44 records · Page 3Linked to original sources
PubMed1977

Pancreatitis and renal disease.

Pancreatitis has been described previously following renal transplantation, but not in association with chronic renal failure. Analysis of 168 patients with renal transplants revealed five who developed pancreatitis, three of whom died. All five were on treatment with prednisone and azathioprine. Four patients were seen with definite attacks of pancreatitis and chronic, stable renal failure from a variety of causes. None had received immunosuppressive agents, prednisone nor thiazide diuretics, but two were on regular frusemide. One patient was on maintenance dialysis, which could not be related directly to the pancreatitis. In either group alcohol ingestion, cholethiathiasis, or hypercalcaemia was not a factor. This diagnosis of pancreatitis was established on clinical grounds and serum amylast levels of greater than 900 iu/1. Similar serum amylast elevation was not found ina random group of patients with chronic renal failure. Hyperlipidaemia was not present in any patient with pancreatitis. Although hypercalcaemia and primary hyperparathyroidism was not found in the transplant and non-transplant subjects, elevated serum parathormone levels have been described in uraemic patients with normocalcaemia. Hyperparathyroidism may be a factor in the development of pancreatitis in reanl failure. Pancreatitis carries a significant mortality risk in renal transplantation. The four non-transplanted patients have survived, despite recurrent attacks of pancreatitis.

Acute Disease↗
PubMed1975

Warble tone as an audiometric stimulus.

Pure-tone and warble-tone thresholds were compared for 198 normal-hearing inexperienced adult listeners at six frequencies at octave intervals from 250 through 8000 Hz. Results of the analysis of variance procedures showed statistically significant differences (p less than 0.01) for the test frequencies 500, 2000, 4000, and 8000 Hz. Although significant differences were found at four of the six test frequencies, mean differences were quite small, the largest being 2.3 dB at 8000 Hz. This finding is thought to support the notion that the audiologist may use warble tone with stimulus parameters up to and including frequency deviations of +/- 5% with modulation rates of five per second to measure thresholds, which are directly comparable to pure-tone thresholds for patients with normal hearing and those with relatively flat hearing loss.

Acoustic Stimulation↗
PubMed1975

Diplacusis associated with bilateral high frequency hearing loss.

Seven normal-hearing subjects and seven subjects with mild bilateral high-frequency sensorineural hearing losses were studied to explore the presence of diplacusis. A tracking procedure of psychophysical method of adjustment-limits was used for pitch judgments rather than the traditional method of adjustment. Each subject was presented with a standard 4000-Hz tone for 500 msec and alternately a variable tone for 500 msec. Subjects were instructed to adjust the variable tone upward or downward in pitch to bracket the pitch sensation of the standard tone. Two intra-aural and two interaural listening conditions were studied. A graphic representation of the subjects' adjustments of the variable tone was obtained for each condition. The resulting tracing indicated frequency correlated to the pitch adjustments from which excursion width and constant error were calculated. Some hard-of-hearing subjects and one normal-hearing subject were found to have diplacusis. Subjects with hearing losses exhibited larger excursion widths for intra- and interaural listening conditions. Subjects with hearing losses tended to be less consistent in pitch judgments than normal-hearing subjects. These findings were interpreted to mean that bilaterally symmetrical hearing losses increase the incidence of pitch aberrations.

Adolescent↗
PubMedDate not supplied

Functional Xp disomy and hypomelanosis of Ito.

BACKGROUND: Hypomelanosis of Ito (HI) is a neurocutaneous phenotype that reflects different mosaicisms, including functional imbalances secondary to chromosome-X inactivation patterns in certain X;autosome translocation carriers. METHODS: We assessed X inactivation patterns by means of the human androgen receptor (HUMARA) assay and BrdU labeling in affected and unaffected skin of a young female with HI and a de novo t(X;13)(Xp13q;Xq13p). PCR analysis was carried out in DNA extracted from uncultured and cultured skin, whereas the BrdU replication patterns were sought in cultured fibroblasts. Parental DNA was also tested. Fluorescence in situ hybridization (FISH) with X and 13/21 centromere probes (DXZ2 and D13Z1/D21Z1) and a cosmid for the X inactivation center were also performed to refine breakpoint assignments. RESULTS: An X inactivation pattern implying functional Xpter-->q11 disomy was found in DNA extracted from uncultured hypopigmented skin, whereas preferential inactivation of the normal X was observed in uncultured normal skin as well as in cultured fibroblasts (after one passage) from both affected and unaffected skin areas. PCR analysis also showed paternal origin of the translocation. BrdU labeling of metaphases from hypopigmented and normal skin primary cultures showed der(Xq13p) to be inactive in about 25% of the cells. FISH revealed that der(Xp13q) had a compound centromere, whereas der(Xq13p) retained 13 centromere repeats but lacked X centromere sequences. Hence, breakpoints were assigned to Xq11 and 13q10. The X inactivation center cosmid gave a signal on both normal X and der(Xp13q), indicating that the inactivation center was not disrupted by the translocation. CONCLUSIONS: These findings confirm that mosaic functional Xp disomy, rather than disruption of X-linked genes, is associated with HI and involvement of the central nervous system (CNS) in some carriers of a structurally balanced X;autosome translocation.

Chromosomes, Human, Pair 13↗
PubMedDate not supplied

The parental origin of de novo X-autosome translocations in females with Duchenne muscular dystrophy revealed by M27 beta methylation analysis.

The parental origin of 3 de novo X-autosome translocations in females with Duchenne Muscular Dystrophy (DMD) was studied by means of methylation analysis using the X-linked probe M27 beta. In all three the translocation was found to be paternal in origin. The parental origin of X-autosome translocations in females with and without DMD is compared with other structural abnormalities of the X and with autosomal translocations.

Animals↗
PubMedDate not supplied

A comparison of procedures and materials for speech reception thresholds.

Ascending and descending procedures were used to obtain speech reception thresholds from 32 normal-hearing subjects whereas digits and spondee words were used as test materials. Comparisons of thresholds were made for the two procedures and materials. Results indicated that slightly lower (less SPL) speech thresholds resulted from the use of a descending procedure with both types of material. In addition, digit material was found to yield generally lower threshold values than spondees. Advantages to the use of the two procedures and materials are discussed.

Adult↗
PubMedDate not supplied

Relative efficiency of warbled-tone and conventional pure-tone testing with children.

Thirty-four normal-hearing 4-year-old children were tested with conventional steady-state pure tones and with warbled tones to compare efficiency of the stimuli. Three measures of efficiency were used: (1) amount of time to train a child to perform the experimental task; (2) amount of time required to obtain thresholds; and (3) number of ascents used for obtaining thresholds. The strong implication by the literature that warbled tones would result in greater clinical efficiency was not supported by the comparisons of the experimental measures. It was concluded that convincing evidence to persuade the audiologist to select warbled over conventional steady-state pure tones for testing children was lacking.

Acoustic Stimulation↗