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Biomedical subjects

S C White

Publications and source records attributed to S C White.

At least 109 records · Page 6Linked to original sources
PubMed1979

Time-compressed spondaic words as a measure of speech reception threshold.

Lists A and B of the C.I.D. W-1 spondees were time-compressed with a Lexicon Varispeech I unit. SRTs were collected from one ear of each of 60 normal-hearing young adults. No list differences were found. The R ears of 30 Ss were superior to the L ears of 30 Ss by 0.8 db. Mean SRTs collapsed across lists and ears were 9.3-10.7-13.2 db for the compressions in the order 0-40-60%. The differences were judged clinically insignificant, nevertheless when considered with earlier data it may be concluded that time-compressed spondees may come to have use as a clinical device.

Adult↗
PubMed1978

Morphometric and fine structural study of experimental autoallergic sialadenitis of rat submandibular glands.

To further our understanding of the immunopathologic mechanisms involved in experimental autoallergic sialadenitis of rat submandibular gland (EAS), histometric and fine structural studies were undertaken. Rats were immunized with allogeneic submandibular glands (SMG) emulsified in complete Freund's adjuvant. Control rats were not treated (C) or adjuvant treated (At). The rats were sacrificed 7, 14, 21 and 28 days after immunization and their SMG were processed for light and electron microscopy. Groups "C" and "at" showed normal acini and ducts. The SMG at 14 days showed significant loss of acini and granular ducts, severe lymphocytic infiltration and the appearance of undifferentiated ducts. The cells of the latter showed abundant free ribosomes, few profiles of rer, no secretory granules and in some cells autophagic vacuoles. Pseudopods of many lymphocytes were found in juxtaposition to degenerating parenchymal cells, mast cells and eosinophils. The extralobular ducts were significantly increased at 7, 14, and 21 days. The immunized glands showed evidence of regeneration at 21 and 28 days. Terminal tubule cells, proacinar cells and acinar cells, at various stages of maturation, were found in the regenerating glands.

Animals↗
PubMed1978

Intraoral xeroradiography.

This study compared the diagnostic usefulness of images of dental structures made with two xeroradiographic (XR) processes with those made by conventional radiography. The xerographic systems employed were a Xerox 125 system (designed for mammography) as well as a new experimental xerographic instrument designed for dental use. Structures evaluated included osseous trabecular detail, caries, dental anatomy, soft tissue, and dental restorations. In general, the resolution and detail of these dental structures were noticeably better on conventional films than on the XR 125 images. In addition, the presence of artifacts around the margins of metallic restorations on the XR 125 image severely inhibited detection of recurrent caries. In contrast, XR images formed by the new experimental process were equal to or superior to conventional films in resolving detail of dental struitures. Also, the experimental XR process required less radiation exposure than conventional radiography.

Dental Caries↗
PubMed1978

Interpatient microbiological cross-contamination after dental radiographic examination.

Pairs of patients were evaluated for microbiological cross-contamination after radiographic examination. In 30 of these pairs of patients there was the possibility of transference of S pyogenes, S aureus, or D pneumoniae. Such transference was observed in 23 (77%) of these 30 pairs of patients. The vectors for such transfer include the hands of the X-ray technician and the radiographic equipment. Further, it was found that each of these organisms would survive for at least 48 hours after being placed on an X-ray tube. Since interpatient microbiological cross-contamination can occur after routine radiographic examination, in some cases, disinfection of the radiographic equipment is indicated.

Cross Infection↗
PubMed1977

An estimation of somatic hazards to the United States population from dental radiography.

Recently, data have become available pertaining both to the estimated somatic hazard from exposure of populations to low doses of ionizing radiation and to the extent of exposure resulting from dental radiography. This has made possible an estimation of the somatic hazard to the United States population from dental radiography. It is concluded that the greatest risk of lethality would result from induction of leukemia, but that the actual hazard is probably quite low. It is advised that all procedures which will reduce the radiation exposure to the patient consistent with diagnostic requirements should be employed in order to minimize the potential risk.

Dose-Response Relationship, Radiation↗
PubMed1977

Relative discernment of lesions by intraoral and panoramic radiography.

Panoramic and intraoral periapical radiographs were compared for their demonstration of pathologic conditions in patients seeking general dental care. Panoramic views allowed additional detection of noteworthy lesions that were not detected by intraoral survey in 5.3% of the cases reviewed, with only 0.1% or one patient in 1,000 possibly requiring treatment. The paucity and lack of urgency of the pathologic conditions discovered solely by panoramic radiography suggest that the expectation of a high incidence of detection of such conditions cannot be used as the sole rationale for the routine use of this procedure as an adjunct to the intraoral survey.

Dental Care↗
PubMed1977

Oral radiographic changes in patients with progressive systemic sclerosis (scleroderma).

Intraoral and panoramic radiographs were made of 35 patients with progressive systemic sclerosis. Of those patients, 13 (37%) were found to have abnormally thickened periodontal ligament spaces. Six of the 35 demonstrated mild to significant resorption of the posterior mandibular angle. Three patients, including two showing angle resorption also had some degree of coronoid process destruction. All patients with this disease should receive initial and follow-up panoramic radiographic examinations to determine any osseous changes.

Adult↗
PubMed1976

The effect of repeated phlebotomy on bilirubin turnover, bilirubin clearance and unconjugated hyperbilirubinaemia in the Crigler-Najjar syndrome and the jaundiced Gunn rat: application of computers to experimental design.

1. A multicompartmental model of erythrokinetics and bilirubin production has been developed to predict the consequences of chronic phlebotomy on daily bilirubin turnover. 2. Control values for four physiological variables including bilirubin turnover were determined in a 20-year-old woman with type I congenital nonhaemolytic jaundice (Crigler-Najjar syndrome). With these base-line data, the model predicted the following changes during phlebotomy: a 34% fall in bilirubin turnover; a 240% increase in the haemoglobin content of bone-marrow erythroid precursors; a 25% fall in the half-life of 51Cr-labelled erythrocytes; a characteristic alteration of the erythrocyte survival curve after labelling with [2-14C]glycine. 3. On the assumption, previously validated in normal volunteer subjects and patients with Gilbert's syndrome, that hepatic bilirubin clearance was independent of turnover and would therefore remain unchanged, a fall in plasma unconjugated bilirubin concentration during phlebotomy from 436 to 282 mumol/1 was expected. 4. Accordingly, the patient underwent phlebotomy 350 ml/week for 2 months, and 500 ml/week during an additional 3 months. Appropriate studies during phlebotomy confirmed each of the predictions in paragraph 2 above. In particular, turnover fell by 31%. Unexpectedly, plasma unconjugated bilirubin remained essentially unchanged. Analogous results were observed in phlebotomized jaundiced Gunn rats. 5. Kinetic studies in both the patient and the rats demonstrated that the failure of plasma unconjugated bilirubin to fall in parallel with bilirubin turnover resulted from a prolongation of the terminal half-life of radioactively labelled bilirubin and a fall in bilirubin clearance in every instance. 6. These studies indicate that (a) in congenital non-haemolytic jaundice, bilirubin clearance is uniquely influenced by bilirubin turnover and (b) compartmental modelling and kinetic studies are useful for predicting and interpreting the results of both physiological experiments and experimental therapeutic regimens.

Adult↗
PubMed1976

A computerized fetal monitoring system.

A computerized fetal monitoring system has been developed at the Cedars-Sinai Medical Center in Los Angeles, California. It utilizes unmodified fetal monitors feeding fetal heart rate and uterine pressure data into a minicomputer. The overall accuracy on internal monitoring is 91%. The concept of on-line computer analysis of fetal monitoring records has met with clinical acceptance and is utilized for all patients in labor at the Cedars-Sinai Medical Center.

Blood Pressure↗
PubMed1975

Mitogen-induced blastogenic responses of lymphocytes from marihuana smokers.

Blastogenic responses in vitro to phytohemagglutinin and pokeweed mitogen were examined in microcultures of peripheral blood lymphocytes from a group of 12 healthy, long-term marihuana smokers and a group of matched control subjects. With either mitogen, no significant difference in cellular incorporation of (3H)thymidine was noted between the groups. These results were interpreted to indicate that the functional status of blood lymphocytes was not altered by long-term smoking of marihuana.

Adult↗