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Biomedical subjects

D W Warren

Publications and source records attributed to D W Warren.

At least 163 records · Page 9Linked to original sources
PubMed1979

Perci: a method for rating palatal efficiency.

This paper describes a new, simple technique for instantaneously rating velopharyngeal competency during speech. The instrument, designed on the basis of data obtained from aerodynamic studies, provides an index of palatopharyngeal closure. Results from model studies and 75 cleft palate subjects demonstrate how the instrument is used to differentiate between problems related to velopharyngeal closure and those resulting from other variables which often influence the performance of speakers with cleft palate.

Adolescent↗
PubMed1978

The effects of 5alpha-reduced androgens on maintenance and regeneration of prostate glands and seminal vesicles in castrated and hypophysectomized rats.

The effects of 5alpha-androstane-3alpha, 17beta-diol (3alpha-diol) and 5alpha-androstane-3beta, 17beta-diol (3beta-diol) were studied in rats hypophysectomized and treated daily for 30 days with the steroids, starting on the day of surgery (hypophysectomized, H) or 30 days following the removal of pituitary (hypophysectomized regressed, HR). The ability of 3beta-diol to maintain and restimulate the prostate glands and seminal vesicles of castrated (C) and castrated regressed (CR) rats, respectively, was also studied. This androgen (3beta-diol) was able to maintain as well as rejuvenate to some degree the sexual accessory glands of all treatment groups. The prostate glands and seminal vesicles in both castrated experimental groups showed increased stimulation with progressively higher dosages of 3beta-diol. At all dose levels, stimulation of seminal vesicles of CR rats was comparable to that of non-regressed castrates. The prostate glands, on the other hand, showed better maintenance in the higher dosage group. In H rats, the stimulation of sexual accessory glands by both androgens was not significantly different than normal controls. The seminal vesicles and prostate glands of HR rats treated with 3alpha-diol were well stimulated and comparable to those of H rats treated with 3alpha-diol. The seminal vesicles of HR rats treated with 3beta-diol were also well stimulated, though not to the extent as those with 3alpha-diol treatment. The prostate glands of the 3beta-diol treated HR rats were significantly smaller than those of the 3alpha-diol treatment group. However, these miniature glands were morphologically stimulated as evidenced by mitosis of parenchymal cells and accumulation of secretory products in the alveoli. This study clearly indicates that 3beta-diol is biologically active and the degree of stimulation varies with the animal preparation in which the androgens were tested.

Androstane-3,17-diol↗
PubMed1978

Posterior pillar webbing and palatopharyngeus displacement: possible causes of congenital palatal incompetence.

Three cases of congenital palatal incompetence in the absence of the usual stigmata associated with hypernasality are presented. In two instances, mucosal webbing of the posterior pillars was noted and in one case the palatopharyngeus muscle was displaced. Hypernasal voice quality was apparent in each patient. A z-plasty on both sides of the posterior pillars is suggested as the treatment of choice when no other morphologic abnormalities are present.

Child↗
PubMed1976

Changes in nasal airway resistance associated with rapid maxillary expansion.

Records consisting of nasal resistance measurements, postero-anterior radiographs, and dental casts were obtained on seventeen patients before they underwent rapid maxillary expansion. These records were retaken after maximum expansion of the appliance and after 3 months of retention. Measurements of nasal resistance, binasal cavity width, and maxillary first molar width were made for each subject at each stage of treatment. The following conclusions were derived: 1. Rapid maxillary expansion produced a significant reduction in nasal resistance measured at both 0.50 L. per second and 0.25 L. per second air flow. The reduction of nasal resistance by maxillary expansion was stable through a 3-month period of retention. 2. There was very low correlation between the amount of maxillary first molar expansion and change in nasal resistance. Also, changes in nasal resistance showed low correlation with the amount of nasal cavity widening which occurred during the expansion procedure. 3. Changes in nasal cavity width was not closely related to the amount of maxillary first molar expansion. 4. The patient's subjective opinion of changes in his ability to breathe through the nose was not closely related to the amount his nasal resistance was reduced. 5. The change in nasal resistance of subjects who noticed an improvement in their ability to breathe through the nose was not significantly different from nasal resistance change in children who did not notice any change in their breathing. 6. When subjects treated with an all-wire expansion appliance were compared to subjects treated with a wire-and-acrylic appliance, the two groups were not significantly different with respect to maxillary first molar expansion, nasal cavity widening, or changes in nasal resistance. Differences in amount of molar tipping or alveolar bending were not investigated. 7. Patients requiring rapid maxillary expansion treatment for constricted maxillary arches have significantly higher nasal resistance than other orthodontic patients and nonorthodontic subjects. The rapid maxillary expansion procedure reduced the nasal resistance of those treated to a level which was not significantly different from that of subjects with maxillary arches of normal dimensions. 8. The reduction in nasal resistance achieved with the expansion procedure was not lost after 3 months of retention. 9. Where indicated, rapid maxillary expansion is not only an effective method for increasing the width of narrow maxillary arches but also reduces nasal resistance from levels associated with mouth breathing to levels compatible with normal nasal respiration.

Adolescent↗
PubMed1976

Anterior open bite and oral port constriction.

Intraoral air pressure and rate of oral airflow were measured simultaneously during fricative sound production in ten subjects with anterior open bite and ten subjects with normal occlusion and speech. From these measurements the area of oral port constriction was calculated and the values compared within and between the two groups. Findings revealed that: (1) The area of oral port constriction was very consistent and reproducible in subjects with normal speech production and normal occlusion. (2) The area of oral port constriction was significantly larger in open-bite subjects compared with control subjects for all sounds. (3) Severe anterior open-bite subjects with a vertical defect over five millimeters were found to produce significantly larger oral port openings than those with only moderate open bite (3-5 mm) for most sounds. (4) A direct correlation between the degree of open bite and the area of oral port constriction was found. As the amount of open bite increased, the area of the oral port increased, especially in the severe open-bite group (5 mm and over).

Adolescent↗
PubMed1975

The effect of gonadotrophins on the fetal and neonatal rat testis.

Testosterone formation was measured in fetal and neonatal (2 h to 20 days) rat testes incubated with and without 100 IU human chorionic gonadotrophin (hCG). At all ages studied, testosterone production was significantly elevated in the presence of hCG. Neonatal testes showed an absolute drop in testosterone production with increasing age, but the percentage increase above baseline produced by hCG stimulation leads to the speculation that this decrease is due to a relative reduction in the number of Leydig cells with increasing age rather than to a lowered sensitivity to hCG stimulation.

Age Factors↗
PubMed1975

The significance of partial suppressibility of serum thyroxine by triidothyronine administration in euthyroid man.

Recent evidence indicates that triiodothyronine (T3) administration may not completely inhibit normal thyroid secretion. To further corroborate this observation, measurement of serum T4-RIA concentrations was performed on 15 normal controls (10 men, 5 women; ages 20-42) who were placed on 100 mug of T3 daily for a 5-week period. Decrements of 53%, 36%, and 28% from the baseline T4-RIA were noted at weeks 1, 2, and 3 respectively. At 3 weeks a nadir T4-RIA of 2.5 mug/100 ml was reached which did not significantly differ from the 4th (2.9 mug/100 ml) and 5th weeks (2.6 mug/100 ml). Further, seven euthyroid patients who had received replacement thyroid hormone for 1-16 were switched to T3 (75-100 mug/day) for 28 days. At the end of this period, their mean T4-RIA was 2.6 mug/100 ml. Similar T3 treatment studies were performed on 20 primary hypothyroid patients. After 4 weeks of T3 all 20 patients displayed a T4-RIA below the limits of assay detectability (less than 0.625 mug/100 ml) while all euthyroid subjects had values greater than 1.2 mug/100 ml. Suppression of T4-RIA with T3 was also noted in 4 patients with pituitary and 2 patients with hypothalamic hypothyroidism. Three days after cessation of T3 treatment in normal subjects, no significant rise in mean T4-RIA was seen (2.3 mug/100 ml). Subsequently, T4-RIA rose to 4.5 mug/100 ml on day 7 and 6.7 mug/100 ml on day 10 (74% of the presuppression value) in normals. A similar rise to 7.9 mug/100 ml 10 days after withdrawal from T3 was noted in the euthyroid subjects who had received long-term thyroid hormone replacement. In contrast, all primary hypothyroid patients had either a minimal or nondetectable elevation in T4-RIA while demonstrating a marked rise in TSH 10 days after T3 withdrawal. An absent or impaired rise in T4-RIA after T3 withdrawal was also noted in patients with pituitary and hypothalamic hypothyroidism. These observations indicated: 1) There is continued thyroidal T4 secretion in euthyroid subjects receiving 100 mug of T3 daily. 2) The hypothesis is advanced that an intact hypothalamic-pituitary-tyhroid axis may be required for continued T4 secretion while on T3. 3) The duration of prior suppression with thyroid hormone medication does not appear to influence this phenomenon.

Adult↗