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Biomedical subjects

T S Davis

Publications and source records attributed to T S Davis.

At least 19 recordsLinked to original sources
PubMed1989

Murder and assault arrests of White House cases: clinical and demographic correlates of violence subsequent to civil commitment.

The authors studied arrest records and clinical data on 217 persons formerly hospitalized as "White House Cases" because they were psychotically preoccupied with prominent political figures. Prior arrest for violent crime was the variable most strongly associated with arrest for violent crime after hospital discharge. Male gender and a history of weapons possession were also correlated with future violence. For those with prior violent crime arrests, hospital incidents requiring seclusion were also associated with later violence. For those without prior arrests, subsequent violence was associated with threats, living outside Washington, and command hallucinations. For those previously arrested for nonviolent crimes, only persecutory delusions were associated with later violence.

Commitment of Persons with Psychiatric Disorders↗
PubMed1988

Marked heterogeneity of aromatase activity in human malignant melanoma tissue.

The prognosis from human malignant melanoma varies according to sex and to multiple histologic, biologic and cell kinetic parameters. Thus melanomas exhibit a major degree of heterogeneity in their biologic properties and further characterization of their biochemical heterogeneity should yield important information. The present study sought to demonstrate the activity of a biochemical marker of estrogen synthesis, the aromatase enzyme, in melanoma tissue and to determine its range of activity. Initially, we validated a highly sensitive radiometric assay for aromatase by comparing it with a direct product isolation method. We detected production of 417 pmol/g protein/h of estrone and 37.3 pmol/g protein/h of estradiol by direct product isolation in a human melanoma and 398 pmol estrone/g protein/h by the radiometric assay. The activity present was blocked by similar amounts of the aromatase inhibitor, aminoglutethimide, as were necessary to block placental, breast cancer, and rat brain aromatase activity. We then assayed aromatase radiometrically in 19 human melanomas and found measurable activity ranging from 9 to 398 pmol estrone/g protein/h in 15 tissues. No relationship with the patient's age or sex was demonstrated. The activity exceeded by 2-fold that previously detected in 49/61 human breast cancers. This study identified a marker enzyme in melanoma tissue which varied by 40-fold among human tumors. Correlation of aromatase activity with prognosis and response to various types of therapy is now necessary to establish the biologic relevance of this finding.

Adult↗
PubMed1988

Soft-tissue expansion in the lower extremities.

Soft-tissue expansion enjoys ever-wider use, but to date an experience using this technique in the lower extremity has never been presented. We reviewed our first 16 patients to describe the indications and contraindications for the use of tissue expansion in the lower extremity. Guidelines evolved from study of the data. Soft-tissue expansion merits consideration for coverage of problem wounds, in preparation for removal of large benign lesions, and for the repair of contour defects. The operator should know that an open wound below the knee predicts a complication if soft-tissue expansion is attempted in that location. In the thigh, incisions can be confidently placed at the edge of the defect. In every location, large expanders should be chosen so that they are as long as or longer than the adjacent defect. The increase in circumference of the limb should be followed. Simple designs for advancement flaps usually work well. As our experience has grown, reconstruction using soft-tissue expansion in the lower extremity has become safer and the results more predictable through better patient selection and diligent monitoring of intraluminal pressures, even if only by ensuring that the patient is always comfortable. Soft-tissue expansion has a role in reconstruction of the lower extremity.

Adolescent↗
PubMed1986

Elimination of lymphangioma circumscriptum by suction-assisted lipectomy.

Lymphangioma circumscriptum presents as cutaneous vesicles or skin tags that drain lymphatic fluid. Deep, sequestered lymphatic cisterns encircled by smooth muscle are thought to be the cause of the skin manifestations, and selective resection of the deep cisterns, not the involved overlying skin, has been suggested as the treatment of choice. We report a successful treatment of lymphangioma circumscriptum using suction-assisted lipectomy to obliterate the deep lymphatic cisterns and their vertical channels communicating to the skin.

Adult↗
PubMed1979

Effects of tourniquet ischemia and postischemic edema on muscle metabolism.

In vivo interstitial muscle pressures measured by wick catheter, tissue gas tensions measured by mass spectrometer, and glucose and high-energy phosphate metabolism measured fluorometrically were studied in the anterior tibial (AT) and vastus lateralis (VL) muscles of primate limbs during and following tourniquet ischemia (2.5 hours; 400 mm Hg) to elucidate postischemic edema and its metabolic consequences. During ischemia, interstitial pressure in the VL rose, while in the AT it decreased, but 24 hours later pressures in both experimental muscles were significantly greater than those in the controls. In both experimental muscles PO2 decreased significantly within 15 minutes of ischemia. PCO2 increased significantly in the AT at 30 minutes and at 75 minutes in the VL muscle. Twenty-four hours later only PO2 in the experimental AT was significantly different than its matched control. During ischemia glucose and phosphocreatine (CrP) decreased significantly, and G-6-P and lactate increased significantly in both muscles, but at 24 hours glucose levels were 25% lower and G-6-P 16.2% higher in the experimental AT and CrP 34% lower in the experimental VL. This study shows that there are significant acute and delayed alterations in primate muscle metabolism following tourniquet ischemia and suggests that these changes may be related to the anatomic location of the muscle studied and the type of trauma it has sustained.

Animals↗
PubMed1979

Hemangioma of the temporalis muscle: a case report and review of the literature.

Hemangiomas are the most common benign tumors of infancy and childhood. Most involve skin and subcutaneous tissues and are readily visible. Intramuscular hemangiomas are very uncommon, and rarely appear in the musculature of the head and neck. A 59-year-old woman who had had a lipoma excised from her left temporal region many years earlier underwent excision of a hemangioma of the left temporalis muscle. Intramuscular hemangiomas do not spontaneously involute and should be removed as soon as they are diagnosed, in order to obviate later destruction of the involved muscle and adjacent tissues. Preoperative embolization of the hemangioma may reduce intraoperative hemorrhaging.

Eyeglasses↗
PubMed1978

The acute effects of tourniquet ischemia on tissue and blood gas tensions in the primate limb.

Tourniquet ischemia results in tissue hypoxia which has been measured indirectly by blood gas analysis. The Medspect mass spectrometer allows direct measurement of gas tension in different tissues and may provide more useful information regarding safe tourniquet times. Calibrated Teflon catheters were inserted into the subcutaneous tissue (11 animals), tibial medullary cavities (bone) (nine animals), and tibialis anterior muscles (10 animals) in both lower extremities of anesthetized stumptail monkeys. Tourniquet ischemia was maintained for 1 hour at 400 mm Hg. Tissue and venous blood gas tensions were recorded from both limbs for 1 1/2 hours. Comparisons between gas tensions in each tissue group were made on the basis of their percentage change from control values. In the ischemic limb within 5 minutes muscle PO2 fell 42 +/- 4% (p is less than 0.001), whereas bone and subcutaneous PO2 dropped 25 +/- 4% (p is less than 0.05). Blood PO2 fell 29 +/- 3% and differed only from that of muscle (p is less than 0.01). One hour after tourniquet inflation, blood PO2 levels has fallen 90 +/- 5% (p is less than 0.001) from their control. Changes in tissue PCO2 were less dramatic and did not vary significantly from those recorded in venous blood. After deflation, blood PO2 exceeded its control by 20 +/- 6% (p is less than 0.005) in 5 minutes, but tissue tensions remained 50 +/- 6% below their control values. These studies indicate that tissue gas tensions are a more sensitive indicator of tourniquet hypoxia than are blood gases within the ischemic extremity.

Animals↗
PubMed1978

Management of fractures of the supraorbital rim.

The frequency of supraorbital rim fractures is increasing as incidence of motorcycle and bicycle accidents increases. These fractures are frequently depressed, comminuted, and often extend into the frontal sinus. Open reduction and fixation are the treatment of choice. Adequate debridement and cleansing with preservation of periosteum and blood supply are recommended. Unstable fragments can be fixed to the frontal bone or stabilized by suturing the torn periosteum. Severely comminuted supraorbital frontal sinus fractures may require stabilization via frontal sinus pack or balloon. We feel the latter is preferable and both Foley and Fogarty catheters have been successfully used.

Adolescent↗
PubMed1978

The team approach to treatment of the cleft lip and palate.

The team consists of a family physician, plastic surgeon, orthodontist, prosthodontist, otolaryngologist, speech therapist, audiologist and social worker. A cleft lip is usually repaired when the child weighs 10 lb., is 10 weeks old and has 10 Gm. of hemoglobin. Defects of the secondary palate are repaired between one and two years of age; residual lip or nasal deformities are corrected before the child starts school. Further cosmetic surgery is delayed until adolescence, when facial growth has been completed.

Child↗
PubMed1977

Cocaine concentrations in the blood during rhinoplasty.

After applying 5% or 10% cocaine to the nasal mucosa, blood concentration were measured in 9 patients undergoing rhinoplasty and in 6 unoperated controls. The concentrations in the unoperated persons were lower than in those undergoing rhinoplasty, and lower concentrations were found after 5% solutions in both groups than in those exposed to 10% solutions. There was no correlation between the strength of the solution used and the degree of bleeding or the success of the anesthesia. One patient developed symptoms of toxicity within two minutes of a 5% cocaine application to his nasal mucosa. The cocaine concentrations in his blood were the highest seen in our studies, and we cannot explain this.

Administration, Intranasal↗