Search PubMed⌕ Search

Biomedical subjects

D Harris

Publications and source records attributed to D Harris.

At least 217 records · Page 12Linked to original sources
PubMed1989

Mild cystic fibrosis linked to chromosome 7q22 markers with an uncommon haplotype.

Cystic fibrosis is the commonest autosomal recessive genetic disorder among northern Europeans and their descendants. Recently, investigators have mapped the gene for cystic fibrosis to chromosome 7. We report the results of DNA linkage analysis in a consanguineous family with mild cystic fibrosis. The probes used in this study were pmet D. pmet H, XV-2c, KM.19, and pJ3.11. Linkage to the identified cystic fibrosis locus of 7q22 was established with a peak logarithm of the odds (lod) score of 3.00 at a recombination fraction theta =0.00 using the tightly linked marker KM.19. In addition, we found the D haplotype, which is not commonly associated with cystic fibrosis, to be segregating in this family. The D haplotype is composed of the 1.4-kb allele detectable by XV-2c and the 6.6-kb allele detectable by KM.19. The three patients with cystic fibrosis who had consanguineous parents were homozygous DD, were among the least severely affected, and had no pancreatic insufficiency. The five patients with unrelated parents were heterozygous for the D haplotype and the commoner B haplotype, except one patient who was homozygous DD. All affected persons with pancreatic insufficiency had the DB genotype. These DNA linkage studies provide additional evidence for the existence of a cystic fibrosis allele that is associated with mild disease.

Adult↗
PubMed1989

Use of the carbon dioxide laser in the drainage of subretinal fluid.

Hemorrhage and retinal perforation are two sight-threatening complications associated with techniques employed to drain subretinal fluid in rhegmatogenous retinal detachment. We hypothesized that the carbon dioxide (CO2) laser would reduce these complications because of its cauterizing action and high absorption in water. The CO2 laser was compared with a conventional technique of using a penetrating diathermy electrode to drain subretinal fluid in rabbits with experimentally detached retinas. No hemorrhage occurred in 223 drainage trials using the CO2 laser, whereas hemorrhage occurred in 21 (4.8%) of 434 trials using the penetrating diathermy electrode. Furthermore, a depth of saline of only 45 microns protected the retina from perforation at CO2 laser dose adequate for drainage. These results indicate that further evaluation of the CO2 laser in treating human retinal detachment is warranted.

Animals↗
PubMed1989

Magnitude estimation and cross-modal matching of lingual vibrotactile and auditory sensation.

The present experiment was a preliminary attempt to use the psychophysical scaling methods of magnitude estimation and cross-modal matching to investigate suprathreshold judgments of lingual vibrotactile and auditory sensation magnitudes for 20 normal young adult subjects. A 250-Hz lingual vibrotactile stimulus and a 1000-Hz binaural auditory stimulus were employed. To obtain judgments for nonoral vibrotactile sensory magnitudes, the thenar eminence of the hand was also employed as a test site for 5 additional subjects. Eight stimulus intensities were presented during all experimental tasks. The results showed that the slopes of the log-log vibrotactile magnitude estimation functions decreased at higher stimulus intensity levels for both test sites. Auditory magnitude estimation functions were relatively constant throughout the stimulus range. Cross-modal matching functions for the two stimuli generally agreed with functions predicted from the magnitude estimation data, except when subjects adjusted vibration on the tongue to match auditory stimulus intensities. The results suggested that the methods of magnitude estimation and cross-modal matching may be useful for studying sensory processing in the speech production system. However, systematic investigation of response biases associated with vibrotactile-auditory psychophysical scaling tasks appears to be a prerequisite.

Adolescent↗
PubMed1989

Benzodiazepines and catatonia: a case report.

The case history of a patient with presumed psychogenic catatonia who responded dramatically to two mg of IM lorazepam is presented. This patient, who had been largely mute and immobile for over a week despite neuroleptic therapy, became freely conversant and mobile within 30 minutes of the administration of lorazepam. This response was repeated the next day after the patient had again become mute and immobile. Catatonia and its diverse etiologies are discussed, with an emphasis on its syndromic nature. The literature on the response of catatonia to the benzodiazepines is reviewed and it is suggested that a trial of benzodiazepines may be helpful in both the evaluation and long term management of patients with catatonia.

Aged↗
PubMed1989

Effects of auditory masking on lingual vibrotactile magnitude-estimation scaling responses of young children.

Studies of lingual vibrotactile magnitude-estimation scaling have focused primarily on the responses of normal young adults. Little is known about the scaling responses of young children to suprathreshold vibratory stimulation because of the complexities of the experimental procedure. Binaural auditory masking is one aspect of the procedure that has recently been studied in adults. The purpose of this study was to investigate the effects of binaural auditory masking on lingual vibrotactile magnitude-estimation responses of young children. Four children whose mean age was 4.6 yr. completed magnitude-estimation scaling tasks for eight lingual vibrotactile suprathreshold intensity levels (6, 10, 16, 20, 26, 30, 36, 40 dB SL) under masking and no masking conditions. Results suggest possible effects of auditory masking on the lingual vibrotactile magnitude-estimation scaling responses of these young children that have not been found for such responses of adults.

Auditory Perception↗
PubMed1989

Lingual vibrotactile threshold shift during magnitude-estimation scaling: effects on magnitude-estimation responses and scaling behavior.

The purpose of the present study was to determine if lingual vibrotactile threshold shifts occurred during magnitude-estimation scaling of suprathreshold stimuli presented to the dorsal surface of the tongue. Possible relationships of the lingual vibrotactile threshold shifts to suprathreshold stimulus intensity, magnitude-estimation responses, and overall scaling behavior were explored. A single group of 24 subjects with an age range of 18 to 22 years participated in this study. Each subject performed two magnitude-estimation tasks. In one of the tasks, threshold of sensitivity was determined after every suprathreshold numerical response of the subject. If a threshold shift was recorded, threshold was allowed to return to the pretest baseline level before continuing to the next suprathreshold stimulus presentation. The results showed that threshold shift did occur during lingual vibrotactile magnitude-estimation scaling, and that it was related to suprathreshold stimulus intensity. The results also showed that the numerical magnitude-estimation responses of the subjects were different for the two scaling tasks. Overall scaling behavior of the subjects in the form of power-function exponents was not different for the two tasks.

Adolescent↗
PubMed1989

Attitudes towards child sexuality.

The way in which North American attitudes contribute to child sexual abuse, so inhibiting abuse prevention education, is examined. A comprehensive literature review identifies sources of materials available to North Americans and determines whether the material includes the identification and anatomical labelling of genitalia. A tendency to avoid doing so is discerned.

Attitude↗
PubMed1989

The benefits and hazards of cosmetic surgery.

The benefits of cosmetic surgery are psychotherapeutic. Patients' symptoms of distress caused by self-consciousness of abnormal appearance are cured by an operation that normalizes the abnormality as the patient sees it. Cosmetic surgery is hazardous when insufficient attention is paid to patient selection, the choice of operation and surgical expertise.

Body Image↗
PubMed1988

Structure of the liganded T state of haemoglobin identifies the origin of cooperative oxygen binding.

A molecular description of haemoglobin's cooperative oxygen binding and release was founded on the X-ray crystal structures of the deoxy-T and oxy-R states. Since the R state's oxygen affinity is close to that of an isolated subunit, the crucial allosteric phenomena are (1) the reduced affinity of the T state and (2) the kinetic pathway between the two quaternary structures. To investigate these phenomena directly, we have determined at high resolution (dmin = 2.1 A) the crystal structures of two liganded T-state haemoglobins. In the liganded T-state alpha subunit, both the tight packing of the haem and the intersubunit contacts inhibit a conformational change between the F helix and FG corner which would allow the haem to become planar and the iron to assume symmetrical R-like coordination. In the beta subunit, by contrast, we find no strain on the proximal side, but the intersubunit contacts prevent the haem from tilting about an axis parallel to the F helix which would open up the binding site to oxygen. In both subunits, ligand binding in the T state induces structural changes towards the tertiary conformation of the R state.

Heme↗
PubMed1988

Exposure effects on the psychophysical scaling methods of magnitude estimation and cross-modal matching for vibrotactile stimulation of the tongue and hand.

The purpose of the present study was to investigate possible effects of exposure upon psychophysical scaling responses when vibrotactile magnitude estimation and cross-modal matching are conducted within the same experiment. Four groups of 10 subjects each, with an over-all age range of 18-23 yr., were employed. Groups 1 and 2 performed magnitude estimation for lingual vibrotaction and cross-modal matching with the lingual vibrotactile stimulus as the standard. Group 1 received the magnitude-estimation task first and Group 2 received the cross-modal-matching task first. Groups 3 and 4 performed magnitude estimation for vibrotaction applied to the thenar eminence of the hand and cross-modal matching with the vibrotactile stimulus applied to the thenar eminence of the hand as the standard. Group 3 received the magnitude-estimation task first and Group 4 received the cross-modal-matching task first. The psychophysical scaling methods of magnitude estimation and cross-modal matching showed very little exposure effect of one upon the other when used in the same experiment. Also, magnitude scaling responses tended to increase more rapidly with increases in vibrotactile stimulus intensity when the test site was the thenar eminence of the hand as opposed to the dorsum of the tongue.

Adolescent↗
PubMed1988

Auditory psychophysical scaling exposure effects: magnitude estimation and cross-modal matching.

The purpose of the present study was to investigate possible effects of exposure upon suprathreshold psychological responses when auditory magnitude estimation and cross-modal matching with audition as the standard are conducted within the same experiment. Four groups of 10 subjects each whose over-all age range was 18 to 23 yr. were employed. During the cross-modal matching task the Groups 1 and 2 subjects adjusted a vibrotactile stimulus presented to the dorsal surface of the tongue and the Groups 3 and 4 subjects adjusted a vibrotactile stimulus presented to the thenar eminence of the right hand to match binaurally presented auditory stimuli. The magnitude-estimation task was conducted before the cross-modal matching task for Groups 1 and 3 and the cross-modal matching task was conducted before the magnitude-estimation task for Groups 2 and 4. The psychophysical methods of magnitude estimation and cross-modal matching showed no effect of one upon the other when used in the same experiment.

Adolescent↗
PubMed1988

Lingual vibrotactile/auditory magnitude estimation and cross-modal matching: comparison of suprathreshold responses in men and women.

The purpose of this study was to investigate the response patterns of men and women to suprathreshold lingual-vibrotactile and auditory stimulation. The psychophysical methods of magnitude estimation and cross-modal matching were used on a group of 10 men (M age = 19.6 yr.) and 10 women (M age = 20.2 yr.). Analysis showed that the men and women performed differently on the magnitude-estimation tasks and similarly on the cross-modal matching tasks. These results suggested that sex differences on suprathreshold psychophysical scaling may be related to the way men and women use numbers as opposed to possible differences in the perception of suprathreshold sensory stimuli by men and women.

Adult↗
PubMed1988

Effect of auditory masking on lingual vibrotactile thresholds and magnitude estimation scaling responses.

Auditory masking has become a frequently employed part of the procedure used in vibrotactile research. Research investigating the effect of auditory masking on lingual vibrotactile thresholds of sensitivity has shown that there is little difference between lingual vibrotactile thresholds under masking and no masking conditions. The purpose of the present study was to extend the investigation of the effect of auditory masking to include lingual vibrotactile suprathreshold scaling responses. 20 young adult subjects of mean age 19 yr. completed lingual vibrotactile-threshold and magnitude-estimation scaling tasks under conditions of bilateral auditory masking and no masking. Similar lingual vibrotactile-threshold values and magnitude-estimation power-function exponents for the conditions of masking and no masking were noted.

Acoustic Stimulation↗
PubMed1988

Physical exercise and sleep: the effect of the age and sex of the subjects and type of exercise.

Exercise has generally been held to result in an increase in slow wave sleep (SWS) and sleep duration. We report the results of three experiments which assessed the effects of exercise on the sleep of young fit women as compared to young fit men; fit older men (aged 41 years) as compared to fit younger men (aged 22 years); and the effects of power exercise on the sleep of a group of trained power lifters. In each experiment physically fit subjects had their sleep assessed following both late afternoon exercise and no exercise conditions. In none of the experiments did exercise result in an increase in SWS or sleep duration. Instead the tendency was for exercise to affect sleep adversely.

Adult↗