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Biomedical subjects

S H Miller

Publications and source records attributed to S H Miller.

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

Analysis of the risk reduction of prophylactic partial mastectomy in Sprague-Dawley rats with 7,12-dimethylbenzanthracene-induced breast cancer.

The effectiveness of prophylactic mastectomy in preventing breast cancer was studied in female albino Sprague-Dawley rats. Group A served as untreated controls. Groups B, C, and D underwent 50%, 75%, and total mastectomies 2 weeks after the administration of 7,12-dimethylbenzanthracene (DMBA). Group E was initially subjected to total mastectomy. Two weeks after surgery, group E received 5 mg of DMBA intravenously. Group F underwent sham procedures. All animals were sacrificed at age 8 months. The mean number of tumors per animal developing in groups A through E was 5.00, 5.17, 4.67, 5.46, and 5.20, respectively. There was 0.21 tumor per animal in group F. The mean time to tumor development in groups A through E was 11.33, 10.05, 9.88, 19.25, and 19.38 weeks, respectively. All results were subjected to an analysis of variance. There was no statistically significant difference in the number of DMBA-induced tumors in groups A through E. Groups D and E had a significant prolonged time to tumor development. The overall risk of the development of breast tumors was not significantly reduced by prophylactic mastectomy. Residual breast tissue after prophylactic mastectomy is at increased risk for the development of breast tumors. The risk of developing breast tumors in this model is not reduced in proportion to the amount of breast tissue removed. (This study suggests that subcutaneous mastectomy in high-risk individuals may not have appropriate prophylaxis against the development of carcinoma of the breast.)

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1985

Denaturation behavior of antithrombin in guanidinium chloride. Irreversibility of unfolding caused by aggregation.

The structural stability of the protease inhibitor antithrombin from bovine plasma was examined as a function of the concentration of guanidinium chloride (GdmCl). A biphasic unfolding curve at pH 7.4, with midpoints for the two phases at 0.8 and 2.8 M GdmCl, was measured by far-ultraviolet circular dichroism. Spectroscopic and hydrodynamic analyses suggest that the intermediate state which exists at 1.5 M GdmCl involves a partial unfolding of the antithrombin molecule that exposes regions of the polypeptide chain through which slow, intermolecular association subsequently takes place. The partially unfolded molecule can be reversed to its fully functional state only before the aggregation occurs. Upon return of the aggregated state to dilute buffer, the partially unfolded antithrombin remains aggregated and does not regain the spectroscopic properties, thrombin-inhibitory activity, or heparin affinity of the native inhibitor. This behavior indicates that the loss of the functional properties of the proteins is caused by the macromolecular association. Comparative experiments gave similar results for the human inhibitor. Analyses of bovine antithrombin in 6 M GdmCl indicated that the second transition reflects the total unfolding of the protein to a disulfide-cross-linked random coil. This transition is spectroscopically reversible; however, on further reversal to dilute buffer, the molecules apparently are trapped in the partially unfolded, aggregated, intermediate state. The results are consistent with the existence of two separate domains in antithrombin which unfold at different concentrations of GdmCl but do not support the contention that the thrombin-binding and heparin-binding regions of the protein are located in different domains [Villanueva, G. B., & Allen, N. (1983) J. Biol. Chem. 258, 14048-14053].

Antithrombins↗
PubMed1985

Aggressive approach to the extremity damaged by electric current.

Electrical current injuries involving the extremities occurred in 41 of 75 patients with electrical burns admitted to the Oregon Burn Center over an 11 year period. Based solely on physical findings, the muscle compartments of 27 limbs in 14 patients were promptly explored, decompressed, and debrided of necrotic tissue on admission. This resulted in the salvage of 10 useful extremities. Major amputation of 11 extremities was carried out during initial surgery. No extremity needing exploration was overlooked. After exploration and fasciotomy, exposed tissues were protected with biologic dressings until repeated explorations and debridements demonstrated the absence of necrotic tissues and closure could be accomplished. The use of both local and free flaps was helpful in closing the wounds. No evidence or renal failure and no deaths attributable to retained necrotic tissue occurred.

Adolescent↗
PubMed1985

Biostereometrics and computergraphics for patients with craniofacial malformations: diagnosis and treatment planning.

Utilizing the techniques of biostereometric photography and current state-of-the-art computergraphics, topographic contourgrams have been generated in a series of patients with complex craniofacial malformations. These contourgrams are considered useful in diagnosis and treatment planning and as an aid in postoperative follow-up. We hope that the technique will provide a means to study longitudinal growth in unoperated and operated patients with craniofacial malformations. Comparisons between these groups and normal patients are currently being investigated.

Adult↗
PubMed1985

Potentiation of infection by epinephrine.

A subinfective dose of Staphylococcus aureus (6 X 10(6)) does not produce wound infection in the rat model. Reducing the dosage (concentration) of epinephrine results in decreased numbers of viable bacteria in tissue and a lower incidence of wound infection in this model.

Animals↗
PubMed1984

Inadvertent intraradial arterial injection of cocaine.

Injection of a chemical irritant into the radial artery at the wrist causes acute discoloration of the skin, edema, and pain in the hand. Subsequent damage due to vasospasm, endarteritis, particulate embolization, and vascular thrombosis may result in ischemic contractures, amputations, and other functional hand deficits. Injection of a street cocaine preparation into the radial artery of a 22-year-old man produced a constellation of signs and symptoms similar to that described for other irritants. Current thoughts with regard to the pathophysiology and treatment of these injuries are reviewed.

Adult↗
PubMed1984

Blunt traumatic rupture of the abdominal wall musculature.

Only 38 cases of blunt traumatic rupture of the anterior abdominal wall musculature have been described in the literature to date. We describe a patient who sustained a complete transection of the right and a partial disruption of the left rectus abdominis muscle as well as multiple associated injuries secondary to blunt, crushing trauma. Postoperatively, he experienced several complications and developed a ventral and right flank hernia. The former was repaired with a rectus abdominis muscle flap and polypropylene mesh. The flank hernia was initially repaired with polypropylene mesh and a recurrence was repaired with latissimus dorsi fascia.

Abdominal Muscles↗
PubMed1984

Complications of embolization treatment for problem cavernous hemangiomas.

Radiologists trained in selective angiography can now deliver sclerosing or occluding materials to the arterial supply of vascular tumors. Such skills require special training and there are limitations to the use of these materials. Specific obliteration can be carried out if this technique is quality controlled. Materials being used for embolization are continually being studied and are changing as new materials are developed. Radiologists can assist surgeons in managing some of these very difficult problems. A large series of patients with various vascular lesions treated at the Oregon Health Sciences University was reviewed. The complications of embolization used for cavernous hemangiomas have tempered our enthusiasm for it as an adjunct form of therapy. We do feel that this method of treatment remains useful in selected cases. The occlusion achieved caused a decrease in both symptoms and size of lesions treated. The decrease in size excluded the need for surgery in 3 cases, aided resection in 1, but caused significant complicating slough in 1. Five cases are presented to demonstrate problems of tissue necrosis encountered.

Adolescent↗
PubMed1984

Management of mandibular fractures in unreliable patient populations.

There is a high incidence of complications following treatment of fractures of the dentulous mandible at our institution, which has led us to scrutinize the criteria for maintaining teeth in the line of fracture and to evaluate other factors that may compromise healing of the fractured mandible, especially in an unreliable patient population. We have reviewed the opinions of various authors and agree that management decisions must be individualized. We recommend prompt and stable immobilization, adequate observation, use of a "tickle file" to keep track of missed appointments, and long-acting intramuscular prophylactic antibiotic coverage, all of which will help minimize morbidity associated with teeth in the line of mandibular fractures, especially in high-risk patients. We also recommend extraction of fully or partially erupted third molars in the line of fracture as well as deeply carious teeth, severely mobile teeth, or teeth with half or more of their root surface exposed to the fracture line. Finally, we recommend that intraoral rather than extraoral open reduction be considered when teeth are to be extracted in order to avoid contamination with the extraoral environment, to enhance surgical access, and to lower postsurgical morbidity.

Adult↗
PubMed1984

The effectiveness of prophylactic subcutaneous mastectomy in Sprague-Dawley rats induced with 7,12-dimethylbenzanthracene.

Fifty-day-old female, albino Sprague-Dawley rats were induced with DMBA, a potent carcinogen that reliably causes multiple breast tumors. Prophylactic subcutaneous mastectomy was performed 2 weeks after injection. Control animals had no breast tissue removed and developed 5.14 tumors per animal, or 1.3 tumors per quadrant. Animals subjected to 50 percent (unilateral) mastectomy developed 5.4 tumors per animal, with 0.72 tumors per surgical quadrant. Animals that underwent 75 percent (three quadrant) mastectomy developed 4.33 tumors per animal, or 0.48 tumors per surgical quadrant. The incidence of tumors was significantly reduced in the surgical areas. However, the risk of any animal developing a breast neoplasm was not reduced in direct proportion to the percentage of breast tissue removed. We believe that this model may prove valuable in evaluating prophylactic subcutaneous mastectomy.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1984

Alterations in local blood flow and tissue-gas tension caused by epinephrine.

Subcutaneous injection of epinephrine markedly reduced local tissue pO2 levels and blood flow while increasing tissue pCO2 in a rat model. The duration and magnitude of these effects were correlated with prolonged elevation of tissue levels of epinephrine and were proportional to the amount of epinephrine injected.

Animals↗
PubMed1983

CT diagnosis of renal cyst wall tumor.

Renal cysts are common lesions especially in the older population. Although the occurrence of a tumor within the wall of an otherwise benign cyst is rare, its accurate diagnosis is difficult. We present such a case, diagnosed preoperatively by computed tomography.

Female↗
PubMed1982

Pyroclastic flow injury. Mount St. Helens, May 18, 1980.

Three patients who were on the periphery of the pyroclastic flow of the Mount St. Helens eruption on May 18, 1980 were treated for severe thermal and inhalation injuries. Although exposed in identical manner, two patients arrived with heavily colonized burn wounds and developed adult respiratory distress syndrome leading directly to their death, whereas the third patient, with a noncolonized burn wound and little evidence of adult respiratory distress syndrome, survived. Evidence of inhaled ash complicating various stages of adult respiratory distress syndrome was confirmed by energy dispersive roentgenographic analysis. In the Pacific Northwest, Alaska, and the Aleutian Islands, potential for further injuries of this type in even larger numbers exists. Should these occur, those who treat the victims should be aware of the potential for severe inhalation problems in addition to the obvious burns.

Adult↗
PubMed1982

Efficacy of triamcinolone acetonide following neurorrhaphy-an electroneuromyographic evaluation.

A primate model to test the effects of triamcinolone acetonide on reinnervation after neurorrhaphy was developed. Reinnervation was assessed in triamcinolone- and placebo-treated nerves. Twelve months after neurorrhaphy, nerves treated with triamcinolone had a faster conduction velocity; a greater amplitude in the evoked response; more and larger axons distally on cross-sectional histological examination; and an evoked response wave form closely resembling normal. We conclude that triamcinolone acetonide instilled locally about a neurorrhaphy immediately after the repair is beneficial for the regeneration of motor nerves in primates.

Animals↗
PubMed1982

Comparison of expanded polytetrafluoroethylene microvascular grafts to autogenous vein grafts.

The use of 1-mm ID by 1-cm-long expanded polytetrafluoroethylene microvascular grafts in various positions in two experimental animals did not compare favorably with the use of autogenous vein interposition grafts in controls. Light microscopy and scanning electron microscopy showed that early fibrin deposition at the anastomosis lines is followed by fully activated coagulation of the grafts. Use of antiplatelet and anticoagulant drugs, changes in techniques, and alterations in the graft material are possible future directions for improved patency with expanded polytetrafluoroethylene microvascular grafts.

Animals↗