Search PubMed⌕ Search

Biomedical subjects

J C Davis

Publications and source records attributed to J C Davis.

At least 145 records · Page 8Linked to original sources
PubMed1976

The effects of orthopedic forces on the craniofacial complex utilizing cervical and headgear appliances.

1. A three-dimensional anatomic model of a human skull was produced with birefringent materials for photoelastic analysis. By means of photoelastic techniques during application of high-pull and cervical extraoral traction, stresses were visualized within the model. 2. Extraoral anchorage affected the position of the maxillary molar and its resulting alveolar development. Cervical headgear had a much greater tipping effect on the maxillary molar than did the high-pull headgear. Both appliances examined could produce stresses which may be transmitted to distant eraniofacial sutures. As opposed to high-pull traction, cervical pull in general stressed more areas and to a much greater degree. 4. The pterygoid plates of the sphenoid bone, the zygomatic arches, the junction of the maxilla with the lacrimal bone and the ethmoid, and the maxillary teeth were affected by both types of headgear. 5. Only cervical traction produced stresses at the frontal process of the maxilla and the Zygomaticofrontal suture. 6. There were two findings which had not been previously reported: First, cervical traction tended to open the palate in the posterior region. Second, high-pull traction produced compressive stresses at the junction of the right and left maxillae inferior to the anterior nasal spine.

Facial Bones↗
PubMed1976

Plasma oestriol and human placental lactogen measurements in patients with high risk pregnancies.

Maternal plasma oestriol and human placental lactogen (HPL) were measured serially in 383 at-risk pregnancies. Eight-five infants were growth retarded and 122 developed fetal distress or neonatal asphyxia. Of the infants whose mothers had either abnormal plasma oestriol or HPL levels, 58 per cent were growth retarded, while 65 and 73 per cent in each group respectively developed fetal distress. The incidence of fetal complications when both plasma oestriol and HPL were abnormal was consistently greater than 66 per cent.

Asphyxia Neonatorum↗
PubMed1976

A gram stain for smears of blood cultures, body fluids and tissues.

A new Gram stain method for blood cultures was adapted from a method for tissue sections. This was accomplished by comparing various modifications of the latter method on positive smears prepared from a 24-hour negative blood culture seeded with Staphylococcus aureus and Escherichia coli. A blind study was then conducted using the new method and Hucker's method on 24-hour and 72-hour blood cultures as well as a limited number of other body fluids and tissues. Of the 35 positive blood cultures detected by the new method, the Hucker method failed to detect 14 positive specimens (40 per cent) upon initial examination. Ten additional cultures were negative using both stains, but were positive on subculture at three days. The 18 additional cultures positive after ten days were detected using only the Hucker stain.

Acinetobacter↗
PubMed1976

Application of hyperbaric oxygen therapy in a case of prolonged cerebral hypoxia following rapid decompression.

The first known and previously unpublished report of the use of hyperbaric oxygen (HBO) in the treatment of prolonged cerebral hypoxia is reported in an incident involving a USAF T-39 aircraft that underwent rapid decompression from 753 mb (2,438 m or 8,000 ft) to 148 mb (13,716 m or 45,000 ft). Within 5 to 8 s, the pilot lost consciousness because he did not don his oxygen mask and, therefore, was unable to obtain supplemental oxygen immediately. After a delay of 6 to 8 min, he was given supplemental oxygen at and below 697 mb (3,048 m or 10,000 ft). On the ground, the pilot was blind and disoriented. This condition persisted for 6.5 h, at which time HBO was administered. Orientation and vision were regained; neurologic findings were negative. It is concluded that HBO therapy was effective in treating this case of prolonged cerebral hypoxia. The report shows 1) the potential application of HBO in the treatment of prolonged cerebral hypoxia, and 2) the need for developing safe procedures for descent of passenger aircraft following such decompressions.

Aerospace Medicine↗
PubMed1975

Treatment of acromegaly with bromocryptine.

Four men and 4 women with active acromegaly were treated with bromocryptine for 4 to 5 weeks. Serum growth hormone levels response to a glucose load were measured before and in the last weed of treatment. In only 1 patient was the grwotoh hormone response rendered normal by the drug. This patient, but none of the others, also showed an improvement in glucose tolerance and a reductin of the raised serum insulin levels during the glucose load. In three of the 8 patients vomiting was troublesome side effect of treatment.

Acromegaly↗
PubMed1975

Relation between thyroid function and serum levels of long-acting thyroid stimulator.

Bioassays of long-acting thyroid stimulator (LATS) were performed in three groups of subjects: in normal controls, in thyrotoxic patients before and serially after 131-I treatment, and in patients with hypopituitarism. Of the untreated thyrotoxic patients, 27.7% had raised serum LATS levels initially. There was no correlation between the relapse rate after 131-I therapy and the initial or subsequent LATS titres: in particular, thyrotoxicosis sometimes recurred after an initially high LATS titre had fallen into the normal range. The distribution of the results of LATS assays in the hypopituitary patients was significantly different from that in the normal subjects; 4 out of 27 hypopituitary patients had LATS levels above the normal range, although they had no thyrotoxicosis. On the other hand, the majority of the patients with hypopituitarism, 19 out of 27, had LATS titres below the mean normal level, possibly due to deficiency of a substance we have termed pseudo LATS. These results raise doubts about a direct causative role for LATS in most cases of thyrotoxicosis.

Biological Assay↗
PubMed1975

Effects of hypothalamic extract and dibutyryl cyclic adenosine monophosphate on follicle-stimulating hormone production in the rat adenohypophysis in vitro.

An assay system, using the characteristic migration of follicle-stimulating hormone (FSH) on polyacrylamide gels, was developed to evaluate the effects of hypothalamic factors on amino acid incorporation into FSH in the rat adenohypophysis incubated in vitro. Follicle-stimulating hormone extracted from rat pituitary secretory granules was found to migrate on 7-5% polyacrylamide gels, pH 9-5, as a protein with an Rf of 0-614. The characteristic Rf was used to measure [14C]amino acid incorpotation into FSH in rat adenohypophyses in vitro. Follicle-stimulating hormone synthesis increased after addition of crude hypothalamic extract to the incubation medium. Hormone synthesis was also increased three times after the addition of dibutyryl cyclic AMP.

Amino Acids↗