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Biomedical subjects

T K Hunt

Publications and source records attributed to T K Hunt.

At least 127 records · Page 7Linked to original sources
PubMed1985

Vitamin E and benign breast "disease": a double-blind, randomized clinical trial.

We report here the results of a double-blind, randomized trial of the effect of vitamin E on clinically palpable benign breast findings. Seventy-three women who attended a breast screening clinic were assigned randomly to either a daily regimen of 600 IU vitamin E (n = 37) or a placebo (n = 36). At the initial visit sociomedical information was obtained for each patient and breast examination performed, with a score ranging from 0 to 4 recorded for each quadrant of both breasts. Thirty-two women in the vitamin E group and 30 in the placebo group returned for follow-up breast examination approximately 2 months later. Scores for mean ages and breast findings at entry were similar for women in the two groups. We found no differences between the vitamin E and placebo groups in scores for changes in breast findings at the end of the study period and no differences in the proportion of women who reported feeling less premenstrual pain (40.0% and 41.4%, respectively). We conclude that in this group of women with breast findings, most of which were not currently serious enough to warrant biopsy, there was no beneficial effect of vitamin E taken during a 2-month course.

Adult↗
PubMed1984

Oxygen as an antibiotic. The effect of inspired oxygen on infection.

Granulocytes' in vitro bactericidal capacity for certain bacteria depends on an adequate environmental oxygen supply. Oxygen available to granulocytes in infected tissue is decreased by local conditions and can be altered significantly by small changes in its inspired concentration. We modified Burke's and Miles' bacteria-injection model in animals to test the effect of breathing 12%, 21%, and 45% oxygen on the size of lesions produced by intradermal injections of Escherichia coli. Moderately increased inspired oxygen concentrations (fraction of inspired oxygen [Flo2]) significantly decreased the size and number of necrotic lesions, whereas hypoxia increased both. Increasing Flo2 to 45% after three and 24 hours of hypoxia also significantly decreased lesion size. Suppression of infection by moderate hyperoxia is comparable with that reported by Burke after timely, adequate doses of type-specific antibiotics.

Animals↗
PubMed1984

Current achievements and challenges in adrenal surgery.

Adrenal surgery is now done in almost ideal circumstances. Mortality and complications are rare except in Cushing's syndrome. All major adrenal hormones and their stimulators are measurable and discriminating tests abound. Imaging techniques detect small masses. Inhibitors of hormone synthesis and cell receptors allow amelioration of metabolic hazards preoperatively. Primary aldosteronism is first medically controlled, and patients are selected for operation if difficult to control and if the type of disease is responsive to adrenalectomy. Cushing's disease usually requires pituitary adenomectomy, but some of the 15-30 per cent failures, those with ectopic adrenocorticotrophic hormone (ACTH) producing tumours, or adrenal adenomas warrant adrenalectomy. Metabolic hazards are controlled pre-operatively by aminoglutethimide. Benefits of adrenalectomy are uncertain and many challenges remain. Hazards of phaeochromocytomectomy are avoided by pre-operative adrenergic blockade. Myocardial disease warrants delay. Small unilateral lesions of all types are best removed through unilateral approaches. Small masses found on imaging and without apparent effect can be observed.

Adenoma↗
PubMed1984

Studies on inflammation and wound healing: angiogenesis and collagen synthesis stimulated in vivo by resident and activated wound macrophages.

Wound inflammatory cells were harvested by aspiration of fluid from the "dead space" of subcutaneous rabbit wounds and transplanted into the cornea where, compared with suitable controls, they stimulated healing (i.e., angiogenesis, fibroplasia, and new collagen synthesis, which led to formation of visible, vascularized scar tissue). Analysis of the data and the literature supports the conclusions that: (1) inflammatory cells control the continuation of the repair process after the immediate effects of injury subside; (2) macrophages, as opposed to granulocytes, appear to be the major contributors; (3) activated by their presence in the wound, macrophages release substances that stimulate fibroplasia, collagen synthesis, and angiogenesis in vivo; and (4) tissue injury is not a maximum stimulus to repair, since endotoxin-treated macrophages have increased capacity to stimulate collagen synthesis and angiogenesis. A hypothesis is offered to explain the notorious clinical discrepancy between the extent of injury and the extent of repair.

Animals↗
PubMed1984

The dynamic properties of tissue oxygen in healing flaps.

Oxygen delivery to random pattern and musculocutaneous flaps was investigated in a canine model. Oxygen tension was measured in the proximal and distal portions of each flap and in adjacent normal skin by means of a recently developed technique. The effect of delay techniques on tissue oxygen tension was also examined with modifications of the same flap model. All measurements were made over a range of inspired oxygen concentrations (21% to 100%) both before operation and at intervals up to 15 days after operation. Tissue oxygen tensions were significantly higher in the musculocutaneous flaps than in random pattern flaps up to 6 days after operation. They were higher in the proximal portions than in the distal portions in each flap type. This difference was greater in the random pattern flap. Delay techniques prevented the early dramatic decrease in postoperative oxygen tension seen in random pattern flaps. Differences in the pattern of oxygen delivery to random pattern and musculocutaneous flaps may in part explain the greater reliability of musculocutaneous flaps when transposed in the presence of infection.

Animals↗
PubMed1983

Oxygen tension regulates the expression of angiogenesis factor by macrophages.

When cultured in a hypoxic environment similar to that found in the center of a wound, macrophages secreted active angiogenesis factor into the medium. Under conditions similar to those of well-oxygenated tissue, macrophages did not secrete active angiogenesis factor. Macrophages that secreted the factor at hypoxic conditions stopped secreting it when returned to room air. Thus the control of angiogenesis in wound healing may be the result of macrophages responding to tissue oxygen tension without the necessity of interacting with other cell types or biochemical signals.

Angiogenesis Inducing Agents↗
PubMed1983

Fine-needle aspiration of palpable breast masses. A program for staged implementation.

Fine-needle aspiration (FNA) can provide a morphologic diagnosis of palpable breast masses in an accurate, efficient, inexpensive, and safe manner. However, how one acquires the skill to perform the FNA and interpret the resulting smears, while protecting the patient from the risk of false-positive or false-negative results, is scarcely considered. We used a three-phase program to acquire experience with FNA while providing services for 205 patients over a 16-month period. We performed FNA sequentially in vitro, in vivo, and finally in vivo for clinical use. With available literature and this graduated implementation program, physicians totally inexperienced with FNA can achieve results similar to those of medical centers having experience with thousands of patients.

Biopsy, Needle↗
PubMed1983

Antibiotic prophylaxis in surgical procedures. A critical analysis of the literature.

The use of prophylactic antibiotics in surgery is widespread and often inappropriate. The lack of well-designed clinical studies partially explains the present confusion regarding the subject. We reviewed the literature in English on antibiotic prophylaxis through June 1982. Antibiotic prophylaxis reduces the incidence of wound infection after colorectal surgery, vaginal hysterectomy, and laryngeal and oropharyngeal resection for carcinoma, and in high-risk patients undergoing gastroduodenal or biliary surgery. In clean operations such as cardiac surgery, vascular procedures, and orthopedic surgery with placement of prostheses, the high morbidity associated with an infection justifies the use of antibiotics even though the risk of infection is small. There are conflicting data on the usefulness of prophylaxis in abdominal hysterectomy, cesarean section, noncardiac thoracic procedures, and urologic surgery. The effectiveness of prophylaxis in neurosurgery cannot be evaluated at the present time.

Administration, Oral↗
PubMed1983

Mammography after needle aspiration of palpable breast masses.

Hematoma resulting from attempted aspiration of a palpable breast mass can cause incorrect mammographic interpretation by rendering irregular and indistinct the otherwise smooth and sharply defined margins characteristic of a benign lesion. In this study of recently aspirated breast masses, we found 17 benign lesions that demonstrated poorly defined, irregular margins on mammograms that suggested malignancy. All these false-positive interpretations occurred when aspiration preceded mammography by less than 2 weeks (17 of 47, 36 percent); no such diagnostic error occurred in the 31 cases when mammography was delayed for 2 weeks or more after aspiration. An appreciation of the frequency and natural history of postaspiration hematoma formation should either encourage physicians to request mammography before carrying out invasive procedures, or alternatively, to defer mammography until 2 weeks after aspiration, since mammography then should more clearly portray the benign characteristics of truly benign masses, thereby possibly obviating biopsy.

Biopsy, Needle↗
PubMed1983

Continuous direct tissue oxygen tension measurement by a new method using an implantable silastic tonometer and oxygen polarography.

A new method of tissue oxygen tension measurement that is suitable for human use has been described. An implanted Silastic tube tonometer is combined with polarographic oxygen electrodes. The techniques of preparation, insertion, and measurement have been described. The advantages and disadvantages of this method have been considered in relation to established methods of tissue oxygen tension measurement. The method is suitable for clinical use and can be used to aid clinical decision-making.

Oxygen↗
PubMed1983

A quantitative in vitro study of fibroblast and endothelial cell migration in response to serum and wound fluid.

Chemoattractant activity for irradiated and nonirradiated rabbit skin fibroblast and bovine aortic arch endothelial cells was assayed in rabbit wound fluid and sera using a modification of the agarose well method originally described for polymorphonuclear leukocytes. Both serum and wound fluid contained chemoattractants for fibroblasts and endothelial cells. Fibroblast migration was decreased by 70 to 80% when the serum or wound fluid was heated to 56 degrees C for 30 min while endothelial cell migration was reduced by 50 to 60%. Platelet-poor plasma-derived serum had no directive effect on the migration of either cell type.

Animals↗
PubMed1983

Direct measurement of wound and tissue oxygen tension in postoperative patients.

An implanted Silastic catheter technique was used to measure partial pressure of oxygen in mastectomy wounds and needle-induced wounds in the subcutaneous tissue of the arms of 33 postoperative patients to assess tissue-wound oxygenation and perfusion on the day of operation and daily through postoperative day five. Characteristic patterns were observed. Wound hypoxia was common and most pronounced after abdominal, vascular, and cardiac procedures. It was most severe immediately after operation. Tissue hypoxia was not easily detected by clinical evaluation and was unknowingly tolerated by experienced surgeons. The relationship between arterial and tissue PO2 is biphasic and presumably curvilinear at the lower range of PaO2 and rises linearly even above the point of full saturation of hemoglobin. Supplemental bolus fluid infusion elevated depressed tissue PO2 in 19 out of 19 measurements, implicating hypovolemia as a common cause of postoperative tissue hypoxia. Measurements of tissue oxygen tension, coupled with a single arterial oxygen determination, constitute a clinically useful means of monitoring tissue perfusion.

Abdomen↗
PubMed1983

Coverage of the infected wound.

Fifty-four consecutive patients with chronic wounds were identified by the following criteria: (1) established infection for 6 months, (2) exposure of bone, mediastinum, or other vital structure, (3) mechanical and/or vascular limitations to delayed closure techniques, (4) no response to wound debridement in prolonged antibiotic therapy. These wounds were divided into four groups: osteomyelitis (21), pressure sore (17), soft tissue wound (10), and osteoradionecrosis (6). Wound treatment in all patients included debridement, muscle flap closure, and culture specific antibiotic therapy. These consecutively treated patients over a 4-year period presented with an average duration of chronic infection of 2.9 years. Ninety-three per cent of these patients after treatment have demonstrated stable coverage without recurrent infection with a minimum of 1 year and a maximum of 4.6 years follow-up. The results demonstrate safe, effective coverage (93% of patients) of chronic infected wounds associated with long bone and pelvic osteomyelitis as well as chronic perineal sinuses following proctocolectomy and osteoradionecrosis. Debridement with short-term (average 12 days) antibiotic therapy has been effective when muscle flap coverage is provided.

Adult↗
PubMed1983

The effect of alpha-adrenergic blockade on cardiac performance and tissue oxygen delivery during excision of pheochromocytoma.

To establish criteria for administration of the optimal dose of alpha-adrenergic receptor blocking drugs, we studied cardiac performance and tissue oxygen tension in three patients who underwent excision of pheochromocytoma. Subcutaneous oxygen tension was measured by the method of Niinikoski and Hunt. Cardiac function was assessed by thermodilution cardiac output, systemic and pulmonary arterial blood pressures, and continuous two-dimensional transesophageal echocardiography of a cross section of the left ventricle at the level of the papillary muscles. Despite large changes in cardiac output and systemic, pulmonary, and wedge pressures, intraoperative tissue oxygen tensions and ejection fractions remained normal (even at times of peak catecholamine excretion and very abnormal wedge pressures). Studies of healthy animals that received no alpha-adrenergic receptor blocking drugs showed major decrements of tissue oxygen in response to modest doses of epinephrine. We conclude that progressive administration of alpha-adrenergic receptor blocking drugs does not absolutely protect the patient from major changes in blood pressure during operation for pheochromocytoma, but that cardiac performance and oxygen supply to the tissues are unimpaired.

Adrenal Gland Neoplasms↗
PubMed1982

Development of a new miniature method for the study of wound healing in human subjects.

A new miniaturized method for evaluation of healing potential in human subjects has been developed. A small, standardized, subcutaneous wound is made in a standard location. Expanded PTFE tubing is placed in the wound and removed at specific intervals. The ingrowth of connective tissue is evaluated by histology and by measurement of hydroxyproline accumulation. Beginning on the fifth day, hydroxyproline accumulation correlates with visual accumulation of tissue in the tubing. Preliminary results show decreased hydroxyproline accumulation in the wounds of patients with preoperative debility. This is to be expected on the basis of previous clinical experience and laboratory studies. This method has the further advantage that the catheters may be placed with local anesthesia in outpatients and therefore may be applied systematically to populations, as well as for observation in patients requiring operation.

Animals↗