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Biomedical subjects

R Sawyer

Publications and source records attributed to R Sawyer.

At least 55 records · Page 3Linked to original sources
PubMed1986

Sialadenoma papilliferum of the adenoids in a 2-year-old child.

We report a case of sialadenoma papilliferum arising in the adenoids in a 2-year-old child. The tumor demonstrated papillary and adenomatous proliferations, suggestive of minor salivary gland origin. A review of the literature indicated no reported cases of this neoplasm arising in individuals this young. The location of the growth also appears to be unique. Regular follow-up by endoscopy and computed tomographic scan of the nasopharyngeal area have not revealed recurrence of disease one year after resection.

Adenoids↗
PubMed1985

Treatment of upper esophageal strictures.

A practical approach to the treatment of upper esophageal and hypopharyngeal strictures is presented. Traditional dilation techniques and instrumentation are reviewed. The size and shape of the stricture are related to the risks of using certain types and sizes of bougies. The adjunctive use of fluoroscopy, urethral dilators, and arteriography materials for esophageal dilation is discussed in light of the dilation treatment option.

Angiography↗
PubMed1983

Benign conditions of the temporomandibular joint: a diagnostic dilemma.

The diagnosis of certain benign conditions affecting the condyle in the temporomandibular joint can be difficult. A spectrum of osteomas, condylar hyperplasia and synovial chondromatosis can all present the same clinical and radiological picture, while the histological appearance may be difficult to interpret and are often misleading. Trauma, local infection or surgery may play a part in the development of these pathologies. A case is reported which clearly illustrates the difficulties of diagnosis of these benign conditions.

Aged↗
PubMed1982

Repair of large pharyngeal defects--new applications of split thickness skin graft.

Stomach and pectoralis major myocutaneous flaps have both been effective in providing hypopharyngeal lining and muscle bulk to close large oropharyngeal fistulae. Their robust musculature has also proven an ideal bed for the application of a split-thickness skin graft, when dealing with the replacement of major anterior neck skin defects. In addition, the pectoralis myocutaneous flap, when half tubed, is an excellent method of reconstructing resected tongue base, markedly improving the function of tongue remnant.

Aged↗
PubMed1982

Ultrastructure of beige mouse peritoneal macrophage lysosomes.

One phenotypic expression of the Chediak-Higashi syndrome in humans and the analogous disorder in the beige mouse (C57BL/6bg/bg) is the presence of anomalous lysosomes identifiable as enlarged cytoplasmic inclusions. This alteration has been used in the study of the circulation and source of certain mononuclear phagocytes in mice. In the present study abnormally enlarged lysosomes are inconsistently demonstrable in the resident peritoneal macrophage of the beige mouse. However, the beige phenotype is also expressed in resident peritoneal macrophages by the presence of anomalous ring form and elongated dumbbell-shaped lysosomes. The former structures resemble those recently described [13] in blood monocytes from patients with the Chediak-Higashi syndrome.

Animals↗
PubMed1981

Does the Catford drum give an accurate assessment of acuity?

Adult emmetropes and myopes were tested with the Catford drum and the results compared with subjective (Landolt C) acuity. For he emmetropes the Catford drum was found to overestimate visual acuity by a factor of approximately 4. For myopes, and emmetropes viewing through plus lenses, the discrepancies were much larger. Since the Catford drum not only overestimates acuity but will do so by a factor which varies for different visual disorders, caution is needed in clinical interpretation of results obtained with it.

Adult↗
PubMed1981

An evaluation of the standard bubble time technique for the measurement of extracorporeal blood flow.

Manual BT is the standard technique to use when measuring Qb for dialysis. An electro-optical system (QB-1) was devised for the measurement of BT and its relationship to real Qb. We investigated the accuracy of standard manual timing methods, the roller pump induced effects of high amplitude low frequency pulses (HALFP), the fundamental pulse of flow (Lp), and the effect of hematocrit (HCT) on BT. Blood with 15, 24, and 38 HCT was used. During dialysis, BT's were measured manually and by QB-1. With Qb greater than 200 ml/min, variations in length became insignificant. HCT did not influence BT at the values studied. In conclusion, 1) QB-1 is more accurate than manual measurements of BT, especially at higher Qb. 2) Qb greater than 200 ml/min dampens the effects of HALFP at any length of tubing. 3) HCT has no effect on BT.

Analysis of Variance↗
PubMed1980

Improving the anti-tumor activity of 5-fluorouracil by increasing its incorporation into RNA via metabolic modulation.

The experiments described here illustrate the use of metabolic modulation to improve the therapeutic effectiveness of 5-fluorouracil (5FUra) in two murine tumor systems (CD8F1 mannary carcinoma and CD2F1 colon tumor 26). The manipulations chosen were based on the assumption that a major fraction of the anti-tumor activity of 5FUra is due to its incorporation into RNA and that the resulting 5FUra-RNA creates difficulty for a variety of cellular mechanisms requiring RNA processing and function. This hypothesis leads to the prediction that thymidine would promote the anti-neoplastic effect of 5FUra due to the following possible interactions: (i) sparing 5FUra from catabolic degradation by saturating the relevant enzymes wit thymidine; (ii) selective arrest of normal cells due to feedback inhibition of robonucleotide reductase by the accumulating thymidine triphosphate (TTP); and (iii) the high levels of TTP would also be expected to repress the anabolic conversion of 5FUra to the deoxy derivatives, thus preserving it for entry into RNA. The data show that thymidine (and certain other nucleosides) does in fact markedly stimulate the incorporation of 5FUra into nuclear RNA and that this event is paralleled by a striking icrease in anti-tumor activity. Kinetic analysis reveals that, although the injection of 5FUra leads to an immediate cessation of thymidylate synthetase activity, DNA synthesis continues at a lower rate for 12 hr and then ceases completely. At this point, in contrast to the earlier partial inhibition, the addition of thymidine fails to restore the ability of the tumor cells to synthesize DNA.

Animals↗