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Biomedical subjects

R E Dean

Publications and source records attributed to R E Dean.

At least 37 records · Page 2Linked to original sources
PubMed1988

Use of magnesium-ATP following liver ischemia.

The role of Mg in cardiomyopathies of different etiologies is well known; however, relatively little is known about the changes in hepatic Mg levels following ischemia to the liver. The available information indicates that tissue and mitochondrial Mg levels are altered following global hepatic ischemia and reflow and that such alterations may be responsible for the depressed cellular function during those conditions. Administration of MgCl2 alone following ischemia was ineffective in improving tissue and mitochondrial Mg levels and cellular functions. ATP administration alone following ischemia was also ineffective. However, administration of ATP complexed with MgCl2 increased tissue and mitochondrial Mg levels, tissue ATP stores and cellular functions and proved beneficial for the survival of animals. The potential mechanisms of the beneficial effects of ATP-MgCl2 are discussed. A multicenter clinical trial of ATP-MgCl2 in patients with various adverse circulatory conditions is being initiated in this country.

Adenosine Triphosphate↗
PubMed1987

Surgical treatment of peptic ulcer disease before and after introduction of H2 blockers.

This retrospective study was undertaken to determine if the advent of H2 blockers has altered the surgical treatment and outcome of patients with peptic ulcer disease (PUD). The records of patients having surgery for PUD at Butterworth Hospital, Grand Rapids, Michigan, from 1971-73 (Group 1) and 1981-83 (Group 2) were reviewed. Data recorded included patient and disease characteristics, surgical procedures, morbidity, and mortality. There was a significant difference in mean age: 54 years in Group 1 and 60 years in Group 2. Group 2 had a higher incidence of concomitant medical illnesses. Indications for operation were predominantly of an emergent nature in Group 2, with a marked decline in elective surgeries from 75 per cent to 55 per cent. There was a 15 per cent incidence of nonsurgical complications in Group 2, as opposed to 9 per cent in Group 1. This study demonstrates that the use of H2 blockers and changes in patient characteristics have altered the surgical treatment and outcome of patients with PUD.

Adult↗
PubMed1987

Depressed antigen presentation function and membrane interleukin-1 activity of peritoneal macrophages after laparotomy.

Although major tissue trauma produces profound depression of cell-mediated immunity, it is not known whether surgical trauma (i.e., midline laparotomy) has any adverse effect on the antigen presentation function and membrane interleukin-1 (IL-1) activity of peritoneal macrophages. To study this, C3H/HEJ (endotoxin-tolerant) mice were anesthetized. An approximately 1-inch midline abdominal incision was made, followed by abdominal closure. On days 1, 3, 5, and 7, peritoneal macrophages were harvested by means of peritoneal lavage, and antigen presentation capability was tested by incubating various numbers of peritoneal macrophages with 2 X 10(4) D10.G4.1 cells per well in the presence of conalbumin (400 micrograms/ml). The T helper cell clone (D.10.G4.1) proliferates on recognition of conalbumin in the context of Iak and also proliferates in the presence of membrane-bound IL-1 plus concanavalin A. To measure membrane IL-1 expression in peritoneal macrophages, Concanavalin A (10 micrograms/ml) was substituted for conalbumin. Cultures were incubated for 72 hours, pulsed with tritiated thymidine, and harvested. Peritoneal macrophages from laparotomized mice induced significantly less T helper cell proliferation on days 1 and 3 in the antigen presentation assay (37% and 30%, respectively; p less than 0.05) and in the membrane IL-1 assay (14% and 10%, respectively; p less than 0.05) as compared with the control. This difference was not detectable on day 5. More effective antigen presentation capability (167% of control; p less than 0.05) was seen on day 7. Thus laparotomy by itself produces marked depression of both antigen presentation function and membrane IL-1 activity of peritoneal macrophages, which may enhance susceptibility to intra-abdominal sepsis.

Animals↗
PubMed1986

Addition of branched-chain amino acids to parenteral nutrition of stressed critically ill patients.

We compared the efficacy of a total parenteral nutrition solution supplemented with 44.6% branched-chain amino acids (BCAA) to standard total parenteral nutrition (19.0% BCAA) in the support of critically ill patients. After a 4-day administration of a randomly assigned solution, amino acids were assayed from femoral venous and arterial samples. The BCAA-supplemented solution caused increases in arterial concentrations of valine, isoleucine, and leucine compared to the control solution. The femoral arteriovenous differences for these BCAA were more positive in patients given the control solution. There were no significant differences in nitrogen balance. Since previous studies showing promotion of nitrogen balance with BCAA did not use a balanced substrate for nonprotein caloric support, the lack of a significant difference in the present study may be due to effective utilization of lipid as a fuel source by both groups.

Adult↗
PubMed1985

Comparison of the diagnostic methods used in maxillofacial trauma.

A prospective study was performed to evaluate the diagnostic methods used in acute maxillofacial trauma. Clinical examination, routine facial x-rays with linear tomography, and computer tomography were compared in 49 patients. Computer tomography was found to be the most accurate test in the diagnosis of facial bone injury, especially complex fractures. Computer tomography also provided valuable information regarding soft-tissue injury of the face. The radiation doses of linear tomography and computer tomography were calculated to be below the level known to cause cataract formation. Computer tomography is a safe, reliable adjunct in the diagnosis of acute maxillofacial trauma and should be strongly considered after initial screening measures are completed.

Adolescent↗
PubMed1985

Fibronectin. A new nutritional parameter.

Acute and chronic malnutrition is associated with increased morbidity and mortality in surgical patients. Plasma fibronectin levels have been shown to correlate with reticuloendothelial function and are reduced in burns, shock, trauma, and sepsis. Patients failing to show an increase in fibronectin levels after stress have been shown to do poorly. Starvation studies in human volunteers have demonstrated decreasing plasma fibronectin levels until feeding was resumed. The purpose of this study is to examine the usefulness of fibronectin as an assessment parameter in nutritionally depleted hospitalized patients. Eight patients initiated on parenteral nutrition were studied. Plasma fibronectin, albumin, and transferrin levels were drawn before TPN and repeated at various intervals after total parenteral nutrition (TPN) was begun. Mean pre-TPN transferrin was 198.1 +/- 16.1 gm/dl (nl 220-400). Transferrin levels remained statistically unchanged after 8 to 11 days of TPN. Mean pre-TPN albumin was 3.0 +/- 0.2 gm/dl (nl 3.6-4.8) and also remained statistically unchanged after 8 to 11 days of TPN. The mean fibronectin level pre-TPN was 236.4 +/- 24.4 microgram/ml (nl 370-410). Fibronectin rose statistically (P less than 0.005) after 1 to 4 days of TPN to a mean of 341.9 +/- 30.1 microgram/ml and remained elevated and statistically unchanged after 8 to 11 days of TPN. Six of the eight patients studied survived and had demonstrated at least a 30 per cent increase in fibronectin after 1 to 4 days of TPN. Both patients who died demonstrated minimal increase in fibronectin levels after 1 to 4 days of TPN.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Polytetrafluoroethylene versus autogenous vein grafts for vascular reconstruction in contaminated wounds.

A high incidence of dissolution and disruption of infected autogenous vein grafts has been demonstrated. PTFE, on the other hand, has been shown to maintain its structural integrity in the presence of well-entrenched infection, with a relatively small incidence of anastomotic disruption related to host artery necrosis. In addition, PTFE performed as well as autogenous vein when antibiotics were administered. Therefore, PTFE graft material is advocated for controlled clinical trials in patients with contaminated vascular injuries.

Animals↗
PubMed1984

Assessment of caloric needs in stressed patients.

An accurate assessment of the energy needs of hospitalized patients is necessary to fulfill caloric requirements, yet avoid inducing complications associated with excessive energy provisions. The objective of this study was to compare actual energy needs as determined by indirect calorimetry with several methods for estimating energy needs. These included the Harris-Benedict Equation (HBE), HBE plus factors for stress (ie, trauma, surgery, cancer), Wilmore 's nomogram, and estimates using 25 and 35 kcal/kg. One hundred nineteen parenteral nutrition patients were studied. HBE or the method of 25 kcal/kg was found to be most accurate in predicting energy needs. Stress factor adjustments of HBE significantly overestimated energy needs when compared to indirect calorimetry, as did the use of Wilmore 's nomogram and the factor of 35 kcal/kg.

Aged↗
PubMed1984

Enteral nutrient solutions. Limiting bacterial growth.

Bacterial contamination of enteral nutrient solutions ( ENS ) in FFcess of food product standards is known to occur in the hospital setting. The large amounts of bacteria often given with ENS have been shown to create a reservoir for nosocomial infections, and nonpathogenic bacteria have been implicated. Patient tolerance is dependent on immune status and the bacterial load delivered to the gut. The purpose of this study was to evaluate the bacterial growth-sustaining properties of various ENS and to devise methods to limit bacterial growth. Five commercial products were prepared under sterile conditions. After inoculation with approximately 5 X 10(3) organisms/cm3 of Enterobacter cloacae, each solution was hung at room temperature for 24 hours with samples drawn at fixed intervals and plated for bacterial counts. Bacterial growth rates in Ensure, Travasorb , and Vital were markedly higher than those in Precision and Vivonex. Vivonex was noted to contain potassium sorbate (KS) used as a fungistatic agent. Recent studies have identified KS as a broad-spectrum bacteriostatic food preservative that is federally approved for this use. KS (0.03%) was added to Travasorb inoculated with 5 X 10(3) organisms/cm(3) of E. cloacae. The bacterial growth rate was reduced by 75 per cent, and the final count of 2-3 X 10(4) organisms/ml was within the federally regulated limit for milk. This study suggests that initial inoculum, growth rate, and hang time can be altered to provide a significant reduction in final bacterial counts in ENS .

Enteral Nutrition↗
PubMed1984

Effects of time, temperature, and preservative on bacterial growth in enteral nutrient solutions.

Bacterial contamination and the effects of time, temperature, and preservative on bacterial growth in enteral nutrient solutions were studied. Bacteria were counted after 24-hour incubation of five samples of frozen Travasorb STD (Travenol Laboratories) from the pharmacy and five samples freshly reconstituted in the dietary department. Growth in samples of Travasorb STD prepared in the pharmacy was studied after (1) fresh mixing, 24-hour refrigeration, and 12 hours at room temperature, (2) freezing, thawing, and 12 hours at room temperature, and (3) freezing, thawing, 24-hour refrigeration, and 12 hours at room temperature. Duplicate samples of five products [Ensure (Ross Laboratories), Precision LR (Doyle Pharmaceuticals), Travasorb STD, Vital (Ross Laboratories), and Vivonex STD ( Norwich -Eaton)] were inoculated with Enterobacter cloacae, and growth curves for 24 hours were plotted. This challenge study was repeated using Travasorb STD as a control and Travasorb STD with potassium sorbate added. Bacterial contamination following reconstitution was not significantly different between pharmacy and dietary department samples. Growth after 12 hours at room temperature was not significantly different for the three sets of storage conditions. Logarithmic growth occurred only at room temperature. All products supported growth of E. cloacae, but growth was significantly lower in Vivonex STD (which contains potassium sorbate) and Precision LR. Growth was reduced by 70% versus control at 12 hours in Travasorb STD containing 0.036% potassium sorbate and by 90% with 0.2% potassium sorbate. Microbial growth in enteral nutrient solutions was dependent on the initial inoculum and the storage time at room temperature. Addition of potassium sorbate to these solutions may greatly reduce bacterial growth.

Bacteria↗
PubMed1984

Fine needle aspiration biopsy. A reliable diagnostic tool in the management of thyroid nodules.

Fine needle aspiration biopsy (FNAB) has been suggested as a diagnostic alternative to routine thyroidectomy for solitary thyroid nodules. During a 15-month period, 51 patients underwent FNAB prior to thyroidectomy. FNAB demonstrated an accuracy of 73 per cent in predicting benign or malignant disease and would have reduced the number of thyroidectomies by 55 per cent. Furthermore, it was found to be safe and more cost-effective than traditional thyroid nodule evaluation and management.

Adolescent↗
PubMed1984

Duplication of the cervical esophagus. An unrecognized cause of respiratory distress in infants.

Infants with respiratory distress demand prompt action and thorough evaluation for possible causes. An urgent but infrequent source of upper airway obstruction is a duplication cyst of the cervical esophagus. Standard references omit this diagnosis in the consideration of both respiratory distress and neck masses in infants. Two patients were admitted with respiratory distress and delayed recognition of a neck mass. Contrast and sonographic studies revealed a cystic mass displacing the trachea in each case. Careful excision promptly relieved symptoms, and histopathologic evaluation confirmed the diagnosis. Duplication of the esophagus can compromise the normal airway, thereby presenting with respiratory difficulty prior to recognition of a neck mass. X-ray studies demonstrating displacement of the trachea or esophagus due to a soft-tissue mass and documentation of a cyst by ultrasound will aid in establishing the diagnosis. Surgical principles include aspiration and excision of the mucosal lining, with preservation of the muscular coat and mucosal septum. Duplication of the cervical esophagus should be considered in the differential diagnosis of both respiratory distress and an enlarging neck mass in infants.

Diagnosis, Differential↗
PubMed1984

Influence of programmed textbook review on American Board of Surgery In-service Examination scores.

Documentation of academic achievement throughout training is an essential component to residency accreditation. Resident performance evaluations by attending staff provide good assessments of affective behavior and technical skills, but evaluation of surgical knowledge is often subjective in nature. The American Board of Surgery In-Service Examination has become the standard by which academic performance is measured. Numerous types of educational programs are used to increase the knowledge base of residents. Sporadic reading of a standard surgical text is a common part of many residency programs. In 1981, the Michigan State University/Butterworth Hospital General Surgery Residency opted to drop the surgical text reading in favor of a review of specific topics attuned to resident needs. Results of the 1982 American Board of Surgery (ABS) examination identified a significant decrease in percentile scores and average resident performance. A program requiring a systematic review of a standard surgical text was then initiated. This review involved assigned reading and administration of weekly examinations covering each assignment. Following institution of this program, a dramatic improvement in the total average scores for the entire resident group was noted. Similar improvement was noted in individual group scores (PG I, II, III, IV, and V). Results of this study indicate that reading of a standard surgical text should be a required part of each residency program.

Achievement↗
PubMed1984

Treatment of jejunoileal bypass failure by reanastomosis and gastroplasty in a single-stage procedure. Review of 47 cases.

Jejunoileal bypass (JIB) for morbid obesity has resulted in a variety of metabolic complications requiring reanastomosis. Although reversal of JIB is usually effective in resolving the metabolic problems, weight gain to pre-JIB levels is common. A single-stage operation combining JIB reversal with gastroplasty (RGP) was performed on 47 patients to correct metabolic complications associated with JIB and reduce recurrence of morbid obesity. Mean follow-up time was 20 months with a range of 6 to 37 months. Average weight at the time of revision was 81 kg, 16.6 kg above the mean ideal weight. Approximately 96 per cent of complications leading to reversal were resolved. Mean postoperative weights showed a gradual increase up to 2 years, at which time weight gain stabilized. Patients 2 to 3 years postsurgery average 36.4 kg above ideal weight and 19.8 kg above weight at the time of reversal. Approximately 79 per cent of patients remained below morbid obesity levels. Complications included eight cases of stomal obstruction; two required reoperation. Stomal dilatation was identified in two patients. There were no mortalities. RGP was found to be ineffective in producing weight loss in patients who had not lost significant weight following JIB. This study suggests that JIB reversal with gastroplasty as a single procedure is safe and effective in resolving nearly all JIB complications. RGP is associated with gradual increase in weight for 2 years, after which weight gain appears to plateau. However, return to morbid obesity levels can be prevented in 70 per cent of patients undergoing RGP.

Adult↗
PubMed1983

Acute nonperforating appendicitis. Efficacy of brief antibiotic prophylaxis.

A prospective, randomized, double-blind clinical study was performed to determine the efficacy of perioperative systemic antibiotics in preventing infection after appendectomy for acute nonperforating appendicitis. One hundred three patients received three doses of either placebo (saline, n = 52) or cefoxitin sodium (n = 51). The two groups were similar with regard to age distribution, sex ratio, duration of operation, pathologic condition of appendix, and hospital stay. Postoperative wound infections were detected in 9.6% of the placebo-treated patients, whereas none occurred in the cefoxitin group. All but one infection appeared after discharge. Cost analysis identified a net savings of $ 84 per patient with the use of prophylactic antibiotics. Septic morbidity after appendectomy for nonperforating appendicitis is significantly reduced by systemic antibiotics, and brief administration of a single broad-spectrum agent (cefoxitin) is effective prophylaxis.

Adolescent↗
PubMed1983

Resident ratings of surgical faculty. Improved teaching effectiveness through feedback.

This study was designed to test the effect on teaching effectiveness of providing regular feedback to the faculty of a general surgery residency. A faculty evaluation rating scale was developed as one aspect of an overall "Code of Teaching Responsibility" process. This study compares two cohorts of surgery teaching staff--one during 1980 and the other during 1982 with respect to resident ratings of teaching effectiveness. Thirty-nine identical surgical faculty were in each cohort--19 general surgeons and 20 subspecialty surgeons. The results show that those faculty receiving the lowest ratings in 1980 show the greatest significant improvement in ratings in 1982--even after a statistical artifact was eliminated. Those in the middle range of ratings in 1980 did not change significantly in 1982. The highest rated faculty in 1980 showed a slight decrease in 1982 ratings. There was no difference between mean ratings of general and subspecialty surgeons. These results suggest that negative feedback to surgical residency faculty who are performing least effectively has a more powerful impact than does positive feedback to those teaching staff who are performing satisfactorily.

Evaluation Studies as Topic↗