Sport-specific differences in dynamic visual acuity and gaze stabilization in division-I collegiate athletes.

BACKGROUND: The vestibular-ocular reflex (VOR) integrates the vestibular and ocular systems to maintain gaze during head motion. This reflex is often negatively affected following sport-related concussion. Objective measures of gaze stability, a function mediated by the VOR, such as the computerized dynamic visual acuity test (DVAT) and gaze stabilization test (GST), may have utility in concussion management. However, normative data specific to sport, sex, or concussion history have not been established in collegiate athletes. OBJECTIVE: The objective of this study was to establish normative values for the DVAT and GST in collegiate athletes and explore the effect of sport, sex, and concussion history on VOR assessments. METHODS: The DVAT and GST were completed by 124 collegiate athletes (72 male, 52 female, mean±SD, age: 19.71±1.74 years, height: 173.99±13.97 cm, weight: 80.06±26.52 kg) recruited from Division-I athletic teams (football, soccer and cheerleading). The DVAT and GST were performed in the rightward and leftward directions during a single session in a standardized environment. Normative values for DVAT and GST measures were expressed as percentiles. Non-parametric statistics were used to compare differences between groups based on sex, sport, and concussion history. Alpha was set a-priori at 0.05. RESULTS: Overall, the median LogMAR unit for 124 athletes completing the DVAT was 0 (IQR = 0.17) for both leftward and rightward. The median velocities achieved on the GST were 145 °/sec and 150 °/sec (IQR = 45 and 40) for the leftward and rightward directions respectively. Significant differences were observed between sports (p = 0.001-0.17) for the GST with cheerleading demonstrating higher velocities than the other sports. However, no significant differences were identified based on sex (p≥0.09) or history of concussion (p≥0.15). CONCLUSIONS: Normative estimates for the DVAT and GST may assist in the clinical interpretation of outcomes when used in post-concussion evaluation for collegiate athletes. Although sex and previous concussion history had no effect on the DVAT or GST, performance on these measures may be influenced by type of sport. Sport-related differences in the GST may reflect VOR adaptations based on individual sport-specific demands.

A within-trial cost-effectiveness analysis of primary care referral to a commercial provider for weight loss treatment, relative to standard care--an international randomised controlled trial.

BACKGROUND: Due to the high prevalence of overweight and obesity there is a need to identify cost-effective approaches for weight loss in primary care and community settings. OBJECTIVE: We evaluated the cost effectiveness of two weight loss programmes of 1-year duration, either standard care (SC) as defined by national guidelines, or a commercial provider (Weight Watchers) (CP). DESIGN: This analysis was based on a randomised controlled trial of 772 adults (87% female; age 47.4±12.9 years; body mass index 31.4±2.6 kg m(-2)) recruited by health professionals in primary care in Australia, United Kingdom and Germany. Both a health sector and societal perspective were adopted to calculate the cost per kilogram of weight loss and the ICER, expressed as the cost per quality adjusted life year (QALY). RESULTS: The cost per kilogram of weight loss was USD122, 90 and 180 for the CP in Australia, the United Kingdom and Germany, respectively. For SC the cost was USD138, 151 and 133, respectively. From a health-sector perspective, the ICER for the CP relative to SC was USD18 266, 12 100 and 40 933 for Australia, the United Kingdom and Germany, respectively. Corresponding societal ICER figures were USD31,663, 24,996 and 51,571. CONCLUSION: The CP was a cost-effective approach from a health funder and societal perspective. Despite participants in the CP group attending two to three times more meetings than the SC group, the CP was still cost effective even including these added patient travel costs. This study indicates that it is cost effective for general practitioners (GPs) to refer overweight and obese patients to a CP, which may be better value than expending public funds on GP visits to manage this problem.

Genetic predisposition influences plasma lipids of participants on habitual diet, but not the response to reductions in dietary intake of saturated fatty acids.

OBJECTIVE: SNPs identified from genome-wide association studies associate with lipid risk markers of cardiovascular disease. This study investigated whether these SNPs altered the plasma lipid response to diet in the 'RISCK' study cohort. METHODS: Participants (n=490) from a dietary intervention to lower saturated fat by replacement with carbohydrate or monounsaturated fat, were genotyped for 39 lipid-associated SNPs. The association of each individual SNP, and of the SNPs combined (using genetic predisposition scores), with plasma lipid concentrations was assessed at baseline, and on change in response to 24 weeks on diets. RESULTS: The associations between SNPs and lipid concentrations were directionally consistent with previous findings. The genetic predisposition scores were associated with higher baseline concentrations of plasma total (P=0.02) and LDL (P=0.002) cholesterol, triglycerides (P=0.001) and apolipoprotein B (P=0.004), and with lower baseline concentrations of HDL cholesterol (P<0.001) and apolipoprotein A-I (P<0.001). None of the SNPs showed significant association with the reduction of plasma lipids in response to the dietary interventions and there was no evidence of diet-gene interactions. CONCLUSION: Results from this exploratory study have shown that increased genetic predisposition was associated with an unfavourable plasma lipid profile at baseline, but did not influence the improvement in lipid profiles by the low-saturated-fat diets.

Clinical trial: benefits and risks of immunomodulators and maintenance infliximab for IBD-subgroup analyses across four randomized trials.

BACKGROUND: Benefits and risks of concomitant immunomodulators and maintenance infliximab in inflammatory bowel disease (IBD) patients have not been adequately evaluated. AIM: To assess the effect of concomitant immunomodulator and infliximab maintenance therapy using data from four prospective, randomized Phase 3 trials in IBD patients. METHODS: Overall, 1383 patients from ACCENT I and ACCENT II [luminal and fistulizing Crohn's disease trials] and ACT 1 and ACT 2 [ulcerative colitis trials] were analysed. Patients were treated with placebo or infliximab 5 or 10 mg/kg at weeks 0, 2 and 6 followed by every-8-week maintenance therapy. Clinical response, clinical remission, fistula response, complete fistula response, infection and infusion reaction rates; serum infliximab concentrations and immunogenicity were summarized by baseline concomitant immunomodulator subgroup (use or non-use). RESULTS: Overall, almost 40% of evaluated IBD patients received concomitant immunomodulators. Efficacy, infection, and serious infection rates were generally similar in patients who received maintenance therapy with or without concomitant immunomodulators. There were no consistent differences in serum infliximab concentrations with or without immunomodulators in patients who received scheduled maintenance therapy. Concomitant immunomodulators reduced infusion reactions and immunogenicity. CONCLUSION: Concomitant immunomodulators did not improve efficacy or pharmacokinetics in IBD patients who received maintenance infliximab.

Endoscopic outcomes analysis.

Endoscopic outcomes analysis has become an increasingly important topic as attempts to measure outcomes, define costs, and compare the relative costs and benefits of different diagnostic and therapeutic procedures have become a major focus of the health care community. This article (1) defines the potential benefits and medical effects of endoscopy; (2) reviews the economic and social pressures fostering the increased focus on health care outcomes research; (3) explores the basic principles, approaches, and paradigms used in health care outcomes analysis; and (4) illustrates how health care outcomes research can help to guide therapeutic approaches, such as endoscopy, in patients with abdominal pain or inflammatory bowel disease.

Pretransplant varicella vaccination is cost-effective in pediatric renal transplantation.

Because of the severe complications that may result from varicella zoster virus (VZV) infection following renal transplantation (Tx), transplanted varicella-susceptible children exposed to varicella are typically given varicella zoster immunoglobulin (VZIG) as prophylaxis or are admitted and treated with parenteral acyclovir if VZIG prophylaxis fails. As both VZIG and hospitalization are costly, prevention of varicella infection by vaccination could potentially result in significant cost savings in addition to decreasing morbidity and mortality. To test this hypothesis, we developed a decision-analysis model to evaluate the cost-effectiveness of vaccinating patients with chronic renal failure (CRF) against varicella prior to renal transplant. Under baseline assumptions, vaccination for varicella pretransplant was a cost-effective strategy, with a cost of $211 per patient vaccinated compared with $1,828 per patient not vaccinated. The magnitude of cost savings from vaccination was sensitive to variations in the cost of varicella vaccine, the percentage of patients hospitalized for treatment with acyclovir, and the percentage of patients exposed to varicella infection. One- and two-way sensitivity analyses confirmed that vaccination was the dominant cost-effective strategy under all conditions examined. We conclude that vaccination for varicella pretransplant is cost-effective for patients with CRF, and that the magnitude of cost savings is sensitive to the cost of hospitalization, the percentage of patients exposed to varicella, and the cost of varicella vaccination. Pending results of ongoing studies of the safety and efficacy of VZV vaccine in children with CRF, we recommend that VZV vaccine be given to all children with CRF.

The role of ultrasonography in the diagnosis of pyloric stenosis: a decision analysis.

BACKGROUND/PURPOSE: The appropriate role for ultrasonography (US) as a replacement for the upper gastrointestinal series (UGI) in vomiting infants remains undefined. The authors have used decision analysis techniques to determine whether the use of ultrasonography as an initial screen in vomiting infants is cost effective when compared with the UGI as the only study. METHODS: Two diagnostic strategies were compared: 1) UGI alone and 2) ultrasonography followed by an UGI series in 50% of cases when ultrasonography scan was negative for pyloric stenosis. The test sensitivity (US, 0.9; UGI, 1.0) and test specificity (US, 1.0; UGI, 1.0) and the incidence of pyloric stenosis among vomiting infants presenting to the community pediatrician (0.30) or after a negative examination by an experienced examiner (0.02 to 0.18) were obtained from a review of the literature. The relative charges for ultrasonography and UGI were obtained from a national survey from which the cost ratio of US to UGI was estimated to range from 0.67 to 1.81 with a median of 1.06. RESULTS: Under these baseline assumptions, UGI only was the preferred strategy. The results of the decision analysis were sensitive to, or dependent on, assumptions made regarding the incidence of pyloric stenosis, the US to UGI cost ratio, the sensitivity of the US, and the proportion of patients that proceed to UGI when the US scan was negative for pyloric stenosis. When at least 50% of patients whose US scan was negative for pyloric stenosis proceeded to a UGI, UGI remained the preferred strategy for all cost ratios examined (0.6 to 1.7). Even when no patients proceeded to UGI, the cost ratio of US to UGI had to be less than 0.7 under the typical incidence (0.30) of pyloric stenosis among vomiting infants presenting to the community pediatrician for US to be cost effective. Finally, only UGI was indicated when an olive was not appreciated by an experienced examiner. CONCLUSION: Under assumptions that fit most clinically relevant circumstances, the UGI as the initial study is the most cost-effective radiological diagnostic test in the evaluation of the vomiting infant.

Colonoscopy or sigmoidoscopy as the initial evaluation of pediatric patients with colitis: a survey of physician behavior and a cost analysis.

BACKGROUND: Pediatric patients presenting with colitis, suggestive of inflammatory bowel disease, undergo evaluation with either flexible sigmoidoscopy or colonoscopy. Our objectives were to assess current practice behavior in the evaluation of pediatric patients with colitis and to determine whether flexible sigmoidoscopy or colonoscopy was more cost-effective as the initial evaluation. METHODS: Practice behavior and procedure charges were assessed using a nationwide survey, and costs for diagnostic strategies were compared using a decision analysis program. RESULTS: The vast majority of survey respondents would proceed with colonoscopy if colitis suggestive of Crohn's disease was noted in the rectosigmoid area (81%) or if ulcerative colitis extended proximal to the rectosigmoid area (70%). If colonoscopy would follow if flexible sigmoidoscopy suggested either ulcerative colitis or Crohn's disease (67%), then colonoscopy would result in a savings of 23%. If the evaluation was predetermined to be limited to flexible sigmoidoscopy (16%), then flexible sigmoidoscopy was the cost-effective strategy with savings of 29%. If colonoscopy would follow flexible sigmoidoscopy for Crohn's colitis only (13%), there was no clear cost advantage. CONCLUSIONS: The most cost-effective strategy depends on the physician's need to know the disease location. Our survey results indicate that most physicians chose to establish the extent of disease in both ulcerative colitis and in Crohn's disease; thus initial colonoscopy would be the more cost-effective strategy. When knowledge of disease distribution is not essential for patient care, flexible sigmoidoscopy can lead to substantial cost savings.

Cost-benefit analysis of interferon therapy in children with chronic active hepatitis B.

BACKGROUND: alpha-Interferon is widely accepted for treatment of adults with chronic hepatitis B, but its use remains limited in children, partly because of questions regarding its cost effectiveness. The aim of this study was to evaluate the cost effectiveness of alpha-interferon for children with chronic active hepatitis B. METHODS: We estimated the cost per year of life saved by alpha-interferon therapy for three cohorts of patients with chronic active hepatitis B treated at 2, 12, or 25 years of age. We assumed that only patients with active viral replication would be treated and that alpha-interferon would prevent cirrhosis and hepatocellular carcinoma in a portion of the population treated. We calculated costs per year of life saved. Medical costs and years of life saved were discounted at 5% per year. RESULTS: With a 30% response rate to alpha-interferon, there was a net savings in both money and lives in the children's group with a minimal cost per year of life saved for adolescents ($510) and adults ($934). Years of life saved per person were greater for children (1.0) than adults (0.5). With a 6% response rate, estimated costs per year of life saved for children ($5,700) were one-fourth of those of adults ($22,100). CONCLUSIONS: alpha-interferon therapy for patients with chronic active hepatitis B is cost effective. alpha-Interferon is more cost effective in toddlers than adults because of the smaller dose required and the greater increase in life expectancy of children.

Evaluation of initial noninvasive therapy in pediatric patients presenting with suspected ulcer disease.

OBJECTIVE: To compare the clinical and economic effects of five likely treatment strategies in children with dyspepsia: initial diagnostic endoscopy (EGD) with biopsy for Helicobacter pylori infection; initial EGD without biopsy; H. pylori serology screening and treatment for H. pylori if positive; empiric treatment with antisecretory therapy; and empiric treatment for H. pylori with antibiotics and antisecretory therapy. METHODS: Our decision analysis model incorporated data from published literature on the incidence of duodenal ulcer disease and effect of H. pylori infection. Cost inputs were derived from payments made by third-party payers. For the three noninvasive strategies that did not include immediate endoscopy, endoscopy was performed on the first episode of symptom recurrence. RESULTS: The estimated costs per child evaluated for each strategy were: EGD with biopsy, $1458; EGD alone, $1248; H. pylori serology, $1224; antisecretory, $1160; and antisecretory-antibiotic, $1164. Results were sensitive to the costs of EGD and the likelihood of recurrent symptoms in children. When the cost of endoscopy fell below $950 or if over 65% of patients without ulcers eventually underwent endoscopy, there was no longer a cost advantage for initial noninvasive treatment when compared with EGD alone strategy. CONCLUSION: In a decision analysis model, empiric antisecretory treatment in children with dyspepsia was most cost-effective, eliminating 40% of endoscopies and leading to antibiotic use in only those patients with H. pylori (4%). Further studies to determine the actual recurrence rate of symptoms after empiric antisecretory treatment of children with dyspepsia are required.

Lack of evidence for seasonal variation in extrahepatic biliary atresia during infancy.

Biliary atresia has been reported anecdotally to occur with temporal and geographic clustering suggestive of an infectious etiology. We examined the birth dates of infants with extrahepatic biliary atresia (EHBA) during an 18-year period for evidence of a monthly or seasonal distribution. Sixty-five patients referred for biliary atresia to the University of Michigan over this period were used as index cases. The monthly and seasonal distributions of birth dates of patients with EHBA were compared by chi 2 analysis to the monthly and seasonal birth rates of infants born in Michigan (p < 0.77 and p < 0.91, respectively). No significant difference was identified. A power analysis showed that our study had an 80% probability of recognizing a 30% variation in birth rates grouped over a 3-month period. The monthly and seasonal distributions of conception dates of patients with EHBA were also compared and found not to be significantly different from the conception dates of infants born in Michigan. We conclude that there is no monthly or seasonal variation in the date of birth or the date of conception of infants with biliary atresia.

Update of the Adult and Pediatric Liver Transplant Program at the University of Michigan.

Significant technical innovations and improvements in immunosuppression have been introduced into our liver transplant program since its inception in 1985. The indications for transplantation have been extended to younger and older patients, and simultaneously more patients with comorbidities have been accepted for transplant. The net impact of these changes has been a continuing trend toward improved survival. Overall, patients with hepatitis B or malignancy have had poor survival rates. The introduction of prophylactic anti-hepatitis B immunoglobulin and lamivudine, and better selection of patients with malignancy may improve results for these patients in the future. As in other programs, our most vexing problem is the continuing scarcity of donor organs which has led to an ever-expanding waiting list, more deaths while awaiting transplant, and more suffering before transplantation. The introduction of living donor hepatic transplantation will be of some help in alleviating this shortage. We are confident that the evolution of our program into a joint multidisciplinary structure will provide more efficient, convenient and cost-effective care to our patients.

Antiserum to tumor necrosis factor and failure to prevent murine colitis.

Cytokines regulate many aspects of disease and have been implicated as mediators of the inflammatory reactions in patients with both ulcerative (UC) and Crohn's colitis. We examined the local and systemic appearance of tumor necrosis factor (TNF) and interleukin 6 (IL-6) in an experimental animal model of inflammatory bowel disease. Colitis was induced in CBA/J mice by adding dextran sulfate sodium (DSS), 5% (wt/vol), to their water. DSS-induced colitis is a reproducible animal model for evaluating the role of cytokines in the pathology of colitis. Animals were weighed daily, and stools were checked for the presence of blood. Groups of mice were killed daily, blood samples were taken for measurement of plasma cytokine levels, and colonic samples were taken for histology and measurement of TNF and IL-6 bioactivity. Mice fed DSS developed colitis with bloody diarrhea, weight loss, and colonic inflammation by days 5-9. Histologic examination of the colons showed focal crypt destruction and ulceration. In mice with DSS-induced colitis no TNF was detectable in colonic tissue extracts or in plasma. In contrast, plasma IL-6 was detectable from days 4 to 9 and was detectable in colonic tissue in only a few (two of four) terminally ill animals on day 9. Animals were injected with a neutralizing, polyclonal anti-TNF antiserum that maintained high in vivo neutralizing titers for > or = 48 h. This anti-TNF antiserum failed to block or modify the severity of colitis induced by DSS. Failure to detect local or systemic TNF and failure to prevent colonic inflammation with anti-TNF antiserum showed that TNF is not an inflammatory mediator in DSS-induced murine colitis.

Malnutrition in hospitalized children with congenital heart disease.

OBJECTIVE: To determine the prevalence of malnutrition among hospitalized children with congenital heart disease by age, disease process, and clinical status. DESIGN: Cross-sectional, retrospective chart review. SETTING: Pediatric cardiology units at a 150-bed tertiary care teaching hospital in Ann Arbor, Mich. PATIENTS: Patients (n = 160) were randomly selected from consecutive admissions to the Pediatric Cardiology and Thoracic Surgery Services during a 1-year period. INTERVENTION: None. MAIN OUTCOME MEASURES: Acute and chronic malnutrition, assessed by comparing the patients' weight and height with established means. RESULTS: Acute and chronic malnutrition occurred in 33% and 64% of the patients, respectively. Age, diagnostic category, and symptoms were associated with malnutrition. Eighty percent of infants presented with acute malnutrition compared with 18% of patients of other ages (P < .001). Malnutrition affected 60% of patients with left-to-right shunts, 53% of patients with complex heart disease, and no patients with primary rhythm disturbances. Acute malnutrition affected 11% and chronic malnutrition affected 50% of patients with left-sided heart obstruction. Acute or chronic malnutrition occurred in 70% or more of patients with cyanosis and/or congestive heart failure but in only 30% of patients with neither (P < .001). CONCLUSION: Malnutrition in hospitalized children with congenital heart disease remains common, highlighting the importance of nutritional screening and intervention.

Eosinophilic mucosal infiltrate in infants with congenital gastrointestinal obstruction.

Infiltration of the antrum and small bowel with eosinophils has been reported to be the etiologic factor for intestinal obstruction in adults with eosinophilic gastroenteritis. We report a case of a breast-fed 8-month-old infant with eosinophilic gastroenteritis (EGE), who presented with severe hematemesis and congenital obstruction of the duodenum, to emphasize that not all obstructive symptoms associated with EGE are secondary to eosinophilic infiltration. Our patient displayed many of the classic signs and symptoms of EGE, including an elevated absolute eosinophil count and marked eosinophilic infiltration in mucosal biopsies from the duodenum, stomach, and esophagus. At surgery there was marked dilation of the first portion of the duodenum and obstruction of the second portion due to malrotation of the intestine with Ladd's bands, duodenal stenosis, and annular pancreas. The dramatic clinical response to surgical correction of the duodenal obstruction leaves little doubt that this patient's symptoms were related to the anatomical lesion.

The rat liver epithelial (RLE) cell nuclear protein database.

The master two-dimensional computer database of rat liver epithelial (RLE) cellular proteins (Wirth et al., Electrophoresis 1991, 12, 931-954) has been expanded to include detailed information concerning 1100 nucleoplasmic (cytosolic) and 850 particulate associated [35S]methionine labeled as well as 215 nucleoplasmic and 269 particulate associated [32P]orthophosphate labeled RLE nuclear polypeptides, respectively. The RLE nuclear protein database developed using the Elsie 5 gel analysis system contains both qualitative and quantitative annotations including polypeptide identification number, protein name (if known), molecular weight and pI information, quantitation and polypeptide spot shape, subcellular location, as well as specific information regarding transformation (chemical and spontaneous) and growth-related characteristics. Microsequencing of polypeptides directly from two-dimensional (2-D) blotted membranes has recently been established in our laboratory and provides a highly efficient and rapid means of polypeptide identification in the absence of specific antibodies. At present the RLE protein database is still in the developmental stage and is continually being updated as additional information is obtained. Nonetheless, it is anticipated that knowledge obtained concerning the identification and characterization of specific transformation and/or growth regulatory proteins in the RLE in vitro cell system will not only have direct application to other rodent and human 2-D protein databases currently under development but will also complement them.

Tumor necrosis factor and IL-1 beta expression in pediatric patients with inflammatory bowel disease.

The local release of inflammatory mediators are intricately linked with initiation and propagation of the inflammatory reaction in ulcerative colitis (UC) and Crohn's disease. We have used immunohistochemical staining of colonic biopsies to determine the cell of origin and the location of the cells which synthesize of TNF-alpha and IL-1 beta in patients with UC and Crohn's colitis. Patients were chosen from children aged 7-16 years, who had UC or Crohn's diagnosed following review of colonic biopsies taken during colonoscopy. The patients reviewed had not received treatment for inflammatory bowel disease. Paraffin embedded colonic biopsies were sectioned, deparaffinized, and stained with mouse monoclonal IgG antibodies directed against human recombinant TNF-alpha and IL-1 beta. The colonic lamina propria of all biopsies from patients with UC or Crohn's colitis was expanded with a mixed mononuclear, polymorphonuclear, lymphocytic, and plasmacytic infiltrate. Mononuclear cells distributed throughout the interstitium, stained prominently for both TNF-alpha and IL-1 beta. Plasmacytes, polymorphonuclear leukocytes, small lymphocytes, and foamy macrophages did not stain for either TNF-alpha or IL-1 beta. Transmigrating mononuclear cells in crypt epithelium also stained brightly for both TNF-alpha and IL-1 beta. Colonic epithelial cells did not stain for either TNF-alpha or IL-1 beta.(ABSTRACT TRUNCATED AT 250 WORDS)

Contraction of collagen gels by intestinal epithelial cells depends on microfilament function.

We have developed a model system to quantify the tractional forces generated by intestinal epithelial cells during organization into a confluent epithelial cell sheet. In this model system, IEC-6 cells, a rat intestinal crypt cell line, rapidly contracted collagen gels reducing the gel surface area by 97% at 24 hr. The tractional forces measured by gel contraction were directly related to the number of cells added and were inversely related to the collagen concentration of the gel. Actin microfilament function was required for gel contraction, but microtubular function was not. Fetal bovine serum and protein synthesis were required for maximal gel contraction. IEC-6 (5 x 10(5)) cells per gel and fibroblasts (5 x 10(4)) cells added to collagen gels resulted in contraction of the gels by 50% at 24 hr. Therefore, intestinal epithelial cells and fibroblasts generate tractional forces of similar strength capable of organizing the surrounding extracellular matrix, which should be considered in models of intestinal morphogenesis and repair.

Identification and use of constitutive proteins for the normalization of high resolution electrophoretograms.

Quantitative inter-gel comparisons of proteins separated by high resolution two-dimensional protein electrophoresis present a number of problems. These problems may arise from: variations in pipetting and other mechanical manipulations of samples, protein loss during transfer from the first to the second gel dimension, variations in staining, and/or variations in film development during autoradiography, in the case of radioactively labeled proteins. This study presents a discussion of these issues and a normalization algorithm to deal with variations, which relies on a class of proteins present in most biological samples which by their nature may be considered internal standards. This class consists of proteins which are controlled by constitutive genes. Constitutive genes are genes that are expressed constantly. We have developed an algorithm which is currently available as a subroutine, 'FINDCONS', in the computerized densitometry and protein comparison analysis program, developed by Olson & Miller (1988). This algorithm identifies potentially 'constitutive' proteins. A normalization method employing these potentially 'constitutive' proteins was compared to several others by examining 2D-electrophoretograms of proteins from developing gypsy moths (Lymantria dispar L.) insect tissue. Following normalization, inter-gel comparisons of spots, which were 'identified' as 'constitutive', were observed to vary less in density than when no normalization method was used, or when normalization based on total integrated spot density was used. In addition to its use as a normalization tool, this algorithm and the subroutine FINDCONS may be useful as an aid in biological studies to identify 'constitutive' proteins.