Medical students' self-reported typical counseling practices are similar to those assessed with standardized patients

CONTEXT/OBJECTIVES

We surveyed fourth-year medical students in the Class of 2003 at Emory University School of Medicine, Atlanta, Georgia, about various personal and clinical practices. We were especially interested in the frequency that these seniors reported of talking with patients about nutrition, weight, exercise, alcohol, and cigarette smoking. Because the validity of our findings about these counseling practices was limited by our having only self-reported data from seniors' questionnaires, we developed a standardized patient (SP) examination to test the relationship between what students reported on the questionnaires and how they actually performed with SPs.

DESIGN/SETTING/MAIN OUTCOME MEASURES

As part of a lengthy questionnaire, 88 senior medical students answered these 5 separated questions: "With a typical general medicine patient, how often do you actually talk to patients about: (1) nutrition; (2) exercise/physical activity; (3) weight; (4) smoking cessation (among smokers); and (5) alcohol? (never/rarely, sometimes, usually/always)." As part of their internal medicine subinternship final exam, students clinically assessed 4 SP cases with predetermined risk factors (poor diet, exercise, alcohol, and/or cigarette-smoking habits).

RESULTS

For every risk factor, the proportion of SPs actually counseled was higher for those students who self-reported discussing that risk factor more frequently with their patients. Additionally, the odds of counseling an SP for any risk factor were significantly higher (odds ratio = 1.76-2.80, P < .05) when students reported more frequent counseling.

CONCLUSION

Student self-reports regarding patient counseling may be useful when resources are limited, and the purpose is to grossly and anonymously distinguish between higher and lower performers.

Breast-feeding among women exposed to polybrominated biphenyls in Michigan

In the early 1970s, the largest industrial accident in the United States resulted in widespread contamination of the food supply in Michigan with polybrominated biphenyls (PBBs). The chemical similarity of PBBs to compounds implicated as endocrine disruptors has raised the question of whether PBBs could affect the reproductive system. In the present analysis we examine the relation between serum measurements of PBBs and the frequency and duration of lactation. Persons who lived on or received food from farms exposed to PBBs were enrolled in a registry by the Michigan Department of Public Health. Female members of the cohort were invited to participate in a telephone survey of reproductive outcomes. The three outcomes of interest in the present analysis were a) the decision to breast-feed (yes/no); b) the duration, in months, of breast-feeding as the main source of nutrition; and c) the total duration, in months, of breast-feeding. None of the three outcomes was significantly associated with serum PBB levels, even after controlling for maternal age, previous history of breast-feeding, body mass index, maternal education, household income, history of smoking in the year before pregnancy, consumption of alcohol during the first trimester of pregnancy, history of thyroid disorder, gestational age of the infant in weeks, time to pregnancy, and year of birth.

Determinants of polybrominated biphenyl serum decay among women in the Michigan PBB cohort

Accidental contamination of the food chain in Michigan in 1973 with polybrominated biphenyls (PBBs) led to the establishment of a registry of exposed individuals in 1976. Serum was collected and analyzed for PBB at the time of enrollment and for targeted studies in the following years. We used the archived PBB data to study the elimination of PBB and to identify factors associated with elimination. A total of 380 women >= 16 years of age who had an initial PBB level of 2 ppb and at least two serum samples drawn when they were not pregnant were included in the analysis. The mean initial PBB level was 20.9 ppb (median 4) and mean time between the first and last measurement was 4.2 years (range 0.5-11.1). PBB was assumed to reach equilibrium in the body before substantial amounts were eliminated and before the first serum measurements were taken; therefore, the entire body was modeled as a single compartment for PBB with exponential decay. Subject-specific decay rate estimates were regressed on predictor variables including initial age, body mass index (BMI), smoking history, breast-feeding duration, and parity. In women with an initial PBB level < 10 ppb, the median half-life was 12.9 years; in those with > 10 ppb, the median half-life was 28.7 years. Decay was significantly slower among women with an initial BMI at or above the median (BMI >= 23). The calculated half-life values are estimates of decay and can be used to estimate body burden of PBB at various points in time other than at the time of serum collection.

Outcome after treatment of high-risk papillary and non-Hürthle-cell follicular thyroid carcinoma

BACKGROUND

Treatment of differentiated thyroid cancer has been studied for many years, but the benefits of extensive initial thyroid surgery and the addition of radioiodine therapy or external radiation therapy remain controversial.

OBJECTIVE

To determine the relations among extent of surgery, radioiodine therapy, and external radiation therapy in the treatment of high-risk papillary and non-Hürthle-cell follicular thyroid carcinoma.

DESIGN

Analysis of data from a multicenter study.

SETTING

14 institutions in the United States and Canada participating in the National Thyroid Cancer Treatment Cooperative Study Registry.

PATIENT

385 patients with high-risk thyroid cancer (303 with papillary carcinoma and 82 with follicular carcinoma).

MEASUREMENTS

Death, disease progression, and disease-free survival.

RESULTS

Total or near-total thyroidectomy was done in 85.3% of patients with papillary carcinoma and 71.3% of patients with follicular cancer. Overall surgical complication rate was 14.3%. Total or near-total thyroidectomy improved overall survival (risk ratio [RR], 0.37 [95% CI, 0.18 to 0.75]) but not cancer-specific mortality, progression, or disease-free survival in patients with papillary cancer. No effect of extent of surgery was seen in patients with follicular thyroid cancer. Postoperative iodine-131 was given to 85.4% of patients with papillary cancer and 79.3% of patients with follicular cancer. In patients with papillary cancer, radioiodine therapy was associated with improvement in cancer-specific mortality (RR, 0.30 [CI, 0.09 to 0.93 by multivariate analysis only]) and progression (RR, 0.30 [CI, 0.13 to 0.72]). When tall-cell variants were excluded, the effect on outcome was not significant. After radioiodine therapy, patients with follicular thyroid cancer had improvement in overall mortality (RR, 0.17 [CI, 0.06 to 0.47]), cancer-specific mortality (RR, 0.12 [CI, 0.04 to 0.42]), progression (RR, 0.21 [CI, 0.08 to 0.56]), and disease-free survival (RR, 0.29 [CI, 0.08 to 1.01]). External radiation therapy to the neck was given to 18.5% of patients and was not associated with improved survival, lack of progression, or disease-free survival.

CONCLUSIONS

This study supports improvement in overall and cancer-specific mortality among patients with papillary and follicular thyroid cancer after postoperative iodine-131 therapy. Radioiodine therapy was also associated with improvement in progression in patients with papillary cancer and improvement in progression and disease-free survival in patients with follicular carcinoma.

Silicosis among foundry workers. Implication for the need to revise the OSHA standard

To evaluate the risk of pneumoconiosis among workers in a Midwestern automotive foundry, medical records and silica sand exposure data were analyzed for 1,072 current and retired employees with at least 5 years of employment as of June 1991. Approximately half of these employees had worked at the foundry for 20 or more years. Sixty workers were found to have radiographic evidence of pneumoconiosis. Twenty-eight workers had radiographs consistent with silicosis, of which 25 were consistent with simple silicosis and three with progressive massive fibrosis. The prevalence of radiographic changes consistent with silicosis increased with: number of years worked at the foundry (6% for 20-29 years and 12% for 30 or more years); cigarette smoking (12.2% among smokers with high silica exposure vs. 4.4% among never smokers with high silica exposure); work area within the foundry (cleaning room, core room, mold area, core knockout); and quantitative silica exposure (0.3-2.7% of workers at the current Occupational Safety and Health Administration (OSHA) standard and 4.9-9.9% of workers above the OSHA standard). In addition, the odds of developing radiographic changes consistent with silicosis were increased for African Americans (odds ratio = 2.14, 95% confidence interval 0.85-5.60) in comparison with whites. (The risk was similar when silica exposure was equal, but African-American workers on average had greater exposure to silica, despite having a similar duration of work as white workers.) Another eight workers had radiographic evidence of asbestosis, and 24 had pleural plaques. These asbestos-related changes were not associated with increasing exposure to silica but rather were associated with being in the maintenance department and performing repair work. After controlling for cigarette smoking, race, and exposure to silica at another job besides the foundry, the authors found a 1.45 increased risk of developing a radiograph consistent with silicosis after 20 years of work at the current OSHA standard, and a 2.10 increased risk after 40 years of work at the current OSHA standard. On the basis of these findings, the authors recommend maintaining silica air levels no higher than the exposure level of 0.05 mg/m3 recommended by the National Institute for Occupational Safety and Health.

Menstrual cycles in nurses handling antineoplastic drugs

Given the association between high-dose antineoplastic drug therapy and effects on gonadal function, a cross-sectional study was designed to explore the relationship between low-dose occupational exposure to antineoplastic questionnaire survey of the members of two national organizations for nurses was conducted, resulting in a sample of 1,458 female subjects. Subjects obtained from the two organizations were compared on major demographic and work characteristics and were found to be similar on most factors other than occupational exposure to antineoplastic drugs. An association was found between menstrual dysfunction and current handling of cancer drugs in subjects between ages 30 and 45 years [prevalence odds ratio (OR) = 1.6, confidence interval (CI) = 1.3-1.9]. A logistic regression analysis demonstrated that subjects ages 30-45 who were currently administering antineoplastic drugs had the highest adjusted OR (3.4, CI = 1.6-7.3) when compared with subjects with no previous or current handling. Additional risk factors significantly associated with menstrual irregularity were stress level of work and the interaction of smoking and stress.

Ocular effects of exposure to triethylamine in the sand core cold box of a foundry

OBJECTIVES

To assess the acute and chronic ophthalmological effects of triethylamine exposure among foundry workers.

METHODS

Ocular effects on people currently, previously, and never exposed to triethylamine in a foundry cold box were studied at two points in time. The initial phase included an ocular examination with a slit lamp to assess corneal health, a visual acuity test, and a questionnaire to assess vision symptoms. The follow up included measurements of corneal thickness with an ultrasonic pachymeter and the vision symptoms questionnaire before and after the shift and at the beginning and end of the week. Personal air measurements for triethylamine were also obtained during the follow up.

RESULTS

The vision symptoms of blurriness, halos around lights, and blue hazy vision occurred more often in currently exposed workers than those previously or never exposed to triethylamine. Air concentrations of triethylamine ranged from < 0.33 mg/m3 to 20.3 mg/m3. Among currently exposed workers, symptoms were more common among those with exposure to > 10 mg/m3 of triethylamine (odds ratio (OR) = 3.0, 95% confidence interval (95% CI) 0.35-25.6). No differences in corneal thickness were found in currently or previously exposed workers and those never exposed. No increase in corneal thickness was found after v before the shift.

CONCLUSION

Despite low concentrations of triethylamine and no corneal oedema, workers exposed to triethylamine reported vision symptoms. Possible explanations for these symptoms without corneal oedema are that triethylamine affects ciliary muscle function or that the corneal oedema was transient and not present when corneal thickness measurements were taken. No chronic effects were found in previously exposed workers. Further research is needed to elucidate the mechanism for the reported vision symptoms, which occurred below the current United States eight hour time weighted standard of 100 mg/m3 and the American Conference of Governmental Industrial Hygienists (ACGIH) recommended value at the time of our study of 40 mg/m3. We recommend that air concentrations be maintained to meet the current recommended ACGIH threshold of 4.1 mg/m3.

Impact of metabolic control of diabetes during pregnancy on neonatal hypocalcemia: a randomized study

OBJECTIVE

To test the hypothesis that strict control of diabetes during pregnancy can reduce the risk for neonatal hypocalcemia in infants of diabetic mothers.

METHODS

One hundred thirty-seven pregnant women with insulin-dependent diabetes enrolled before 9 weeks' gestation were randomized to one of two treatment groups. In 68 subjects, the goals were fasting blood glucose level less than 4.44 mmol/L (80 mg/dL) and 1.5-hour postprandial blood glucose level less than 6.66 mmol/L (120 mg/dL) (strict control), whereas in 69 the goals were fasting blood glucose level less than 5.55 mmol/L (100 mg/dL) and 1.5-hour post-prandial glucose level less than 7.77 mmol/L (140 mg/dL) (customary control).

RESULTS

Infants in the strict control group had a significantly lower rate of hypocalcemia (mean calcium less than 8.0 mg/dL in term infants and less than 7.0 mg/dL in preterm infants) than infants in the customary control group (17.6 versus 31.9%; P < .05). Using logistic regression analysis and after adjusting for the effects of gestational age, asphyxia, and White class on hypocalcemia, the difference between groups remained significant. The lowest infant serum calcium concentration correlated significantly with maternal glycohemoglobin A1 concentration at delivery (P = .03), gestational age (P = .0001), and the lowest serum magnesium concentration (P = .0001).

CONCLUSION

Strict management of diabetes in pregnancy is associated with a reduction in the rate of neonatal hypocalcemia.

Fertility of workers chronically exposed to chemically contaminated sewer wastes

Few studies have investigated the reproductive effects of exposure to chemical mixtures. The purpose of this study was to assess fertility in males exposed to mixed industrial and domestic wastes. A detailed reproductive history was obtained from the wives of 231 employees in order to evaluate fertility. Daily work records were used to define exposure status. To ascertain problems of infertility, the ratios of observed live births to expected live births (generated from U.S. birth probabilities) for exposed and nonexposed groups were calculated, and the ratios of these Standardized Fertility ratios (SRFs) were compared. Other analyses considered the couples' contraceptive history and preexposure versus postexposure experience. Though multiple statistical approaches were used to examine the data, the conclusion of this study was that exposure to chemical mixtures was not associated with a decrease in the couples' fertility.

Cold air challenge and platinum skin reactivity in platinum refinery workers. Bronchial reactivity precedes skin prick response

An investigation of a platinum refinery operation consisted of an administered questionnaire, spirometry, skin prick testing with platinum salts and common aeroallergens, serum total IgE, radioallergosorbent test for platinum salts, and measurement of nonspecific airway hyperresponsiveness by cold air challenge testing. Among 136 employees examined, there were 107 current and 29 medically terminated workers; 23 (17 percent) subjects had a positive platinum salts prick skin test and 19 (14 percent) displayed a positive cold air challenge. RAST binding for platinum salts IgE antibodies showed a high level of agreement with platinum skin prick test results. A proportion (63 percent) of the population (74 current and 12 terminated workers) underwent repeat platinum skin testing one year later. Among current workers, there was conversion of the platinum skin test from negative to a positive test in five employees, with three conversions occurring in workers who showed only a positive cold air challenge test the year before. Platinum skin sensitivity, asthma symptoms, and nonspecific airway hyperresponsiveness persisted for years after termination of exposure in some medically terminated workers presumably because of a delay in removal from work of employees who became sensitized to platinum salts. It is suggested that proper surveillance for occupational asthma involves the use of several testing procedures. Prompt removal from work of individuals found to become sensitized to platinum salts is important in this industry.

Measurements of acute cerebral infarction: a clinical examination scale

We designed a 15-item neurologic examination stroke scale for use in acute stroke therapy trials. In a study of 24 stroke patients, interrater reliability for the scale was found to be high (mean kappa = 0.69), and test-retest reliability was also high (mean kappa = 0.66-0.77). Test-retest reliability did not differ significantly among a neurologist, a neurology house officer, a neurology nurse, or an emergency department nurse. The stroke scale validity was assessed by comparing the scale scores obtained prospectively on 65 acute stroke patients to the patients' infarction size as measured by computed tomography scan at 1 week and to the patients' clinical outcome as determined at 3 months. These correlations (scale-lesion size r = 0.68, scale-outcome r = 0.79) suggested acceptable examination and scale validity. Of the 15 test items, the most interrater reliable item (pupillary response) had low validity. Less reliable items such as upper or lower extremity motor function were more valid. We discuss methods for improving the reliability and validity of brief examination scales to be used in stroke therapy trials.

Measurements of acute cerebral infarction: lesion size by computed tomography

As part of a prospective therapy study of 65 patients with acute, nonhemorrhagic, cerebral infarction, computed tomographic scans of the head were obtained at admission, 7-10 days, and 3 months. The scans were analyzed for the presence, site, size, and volume measurement of the infarction. At 7-10 days, the mean infarction volume as measured by computed tomography was 55 cm3 or about 4 x 4 x 3.5 cm (range = 0-507 cm3). At 3 months, the mean infarction volume decreased by 25% to 41 cm3. For the 26 scans showing infarction at the time of admission, the mean lesion volume was 33 cm3 at admission, 51 cm3 at 7-10 days, and 49 cm3 at 3 months. With lesion size at 7-10 days expressed as percentage of total brain volume, the mean infarction size was only 5%. Of the 49 patients with lesions revealed by computed tomography at 7-10 days, 20 had an infarction of 1% or less of total brain volume, while only six had an infarction of 20% or more of total brain volume. The lesion volumes as measured by the 7-10-day computed tomography correlated with the neurologic examination scores on admission (Spearman's rank-order correlation = 0.78) and with the scores at 1 week (Spearman's rank-order correlation = 0.79).

Macrosomia in infants of insulin-dependent diabetic mothers

The purpose of the present study was to evaluate factors affecting the rate of macrosomia and related complications in a population of infants of insulin-dependent diabetic mothers. The following factors were hypothesized to be predisposing to macrosomia: increased maternal weight gain during gestation, increased number of births until infant No. 3, white race, increased maternal age, poor glycemic control from the 20th week of gestation, and increased insulin dose. Advance White classification and increased duration of diabetes were predicted to be inversely related. In addition, macrosomia was hypothesized to predispose to selected adverse perinatal outcomes including premature labor, birth asphyxia, birth injury, hypoglycemia, polycythemia, and respiratory distress syndrome. From 1978 to 1986, 127 pregnancies were prospectively studied, 86 of the total number of women were entered prior to 10 weeks' gestation, and 41 were entered after 10 weeks' gestation. Patients monitored blood glucose at least twice daily with glycemic control achieved by "split-dosage" regimens of insulin. Glycohemoglobin was measured monthly. Pregnancy dating was based on the date of the last menstrual period and the Ballard score of the infant at birth. Macrosomia was defined as a birth weight greater than the 90th percentile of the intrauterine growth curves of Lubchenco. Of the babies born to mothers with insulin-dependent diabetes, 43% were large for gestational age and 57% were appropriate for gestational age.(ABSTRACT TRUNCATED AT 250 WORDS)

Decreased bone mineral content in infants of diabetic mothers

The present study was conducted to test the hypothesis that infants of diabetic mothers (IDMs) have decreased bone mineral content at birth, and whether or not decreased infant bone mineral content in IDMs correlates with poor control of diabetes during pregnancy, maternal bone mineral content, and the development of neonatal hypocalcemia. Forty-five pregnant diabetic women and their infants were enrolled in a prospective trial. In addition, 55 normal newborn infants of nondiabetic mothers were used as controls. Bone mineral content was measured before delivery in all diabetic pregnant patients and at birth in all infants by photon absorptiometry. Bone mineral content was significantly decreased in infants of diabetic mothers compared with control infants and correlated inversely with mean first trimester maternal capillary blood glucose; it did not correlate with cord serum 1,25-dihydroxyvitamin D concentrations. By stepwise multiple regression analysis, in infants of diabetic mothers, bone mineral content correlated inversely with mean first trimester capillary blood glucose and maternal bone mineral content, but did not correlate with maternal blood glycosylated hemoglobin, infant gestational age, infant birthweight or weight percentile, or development of neonatal hypocalcemia.

Variations in serum thyroxine concentrations with time after an oral replacement dose

Serum thyroxine concentrations were measured sequentially in eight healthy male volunteers after the oral administration of one of two brand name, commercially available thyroxine tablets. In all cases, levels peaked at 2 hours and did not return to baseline values until 24 hours after dosing. From 2 through 10 hours, statistically significant elevations in serum thyroxine concentrations were observed. Such fluctuations may be important in evaluating laboratory results in patients receiving replacement doses of thyroxine.

Hypertension as a risk factor for spontaneous intracerebral hemorrhage

To better define the etiologic importance of hypertension for spontaneous intracerebral hemorrhage, hospital records were studied for all patients sustaining intracerebral hemorrhage during 1982 in the Cincinnati metropolitan area. Hypertension pre-dating the hemorrhage was present in 45% (69 of 154), as determined by history. A more inclusive definition of hypertension, combining those with a positive history with those found to have left ventricular hypertrophy by electrocardiogram or cardiomegaly by chest radiography, applied in 56% (87 of 154). The cases were compared to controls with and without hypertension derived from the NHANES II study of blood pressure (n = 16,204) to determine relative risk. For the presence of hypertension by history, the relative risk of intracerebral hemorrhage was 3.9 (95% confidence interval, 2.7 to 5.7). For the inclusive definition of hypertension, the relative risk was 5.4 (3.7 to 7.9). Relative risk was also determined for hypertension in blacks (= 4.4), age greater than 70 (= 7), prior cerebral infarction (= 22), and diabetes (= 3). We conclude that the term "hypertensive hemorrhage" should be used very selectively, particularly in whites, and propose that hypertension be viewed as one of several important risk factors for spontaneous intracerebral hemorrhage.

The continuing impact of thyroid scintigraphy on the diagnosis of thyroid enlargement

The impact of thyroid scintigraphy on the working diagnosis was evaluated in 204 consecutive patients referred for thyroid testing. The a priori and a posteriori diagnoses were discordant about one third of the time. The differences were highly significant (P less than 0.001) in the cases of uninodular and multinodular goiter.

Effect of maternal hyperketonemia in hyperglycemic pregnant ewes and their fetuses

The fetus of the pregnant diabetic woman is exposed to hyperglycemia frequently accompanied by ketoacidosis. Previous studies have demonstrated that beta-hydroxybutyrate, a major ketone body, crosses the ovine placenta in significant amounts, leading to significant reductions in fetal PaO2 and increased fetal heart rate. In the present study the pregnant ewe was used to evaluate the maternal and fetal cardiovascular and metabolic responses to hyperketonemia in the presence of hyperglycemia and to determine if the combined diabetic insults were more detrimental to the fetus than hyperketonemia alone. A glucose priming dose of 25 gm was administered in the maternal femoral vein followed by a continuous glucose infusion of 200 mg/min to achieve steady maternal plasma glucose levels of 180 mg/dl. Once glucose levels were stable, beta-hydroxybutyrate was infused for 2 hours at a rate of 0.39 mmol/100 ml of uterine blood flow into both left and right uterine arteries. Infusion of glucose alone did not significantly alter fetal cardiovascular and blood gas parameters but did increase the fetal glucose level from 17 +/- 4 to 58 +/- 8 mg/dl. The simultaneous infusion of beta-hydroxybutyrate and glucose produced significant decreases in fetal PaO2 and oxygen content as were reported for hyperketonemia alone and significant time-related increases in fetal lactate levels and fetal heart rate. These data suggest that hyperketonemia in the pregnant ewe leads to quantitatively similar changes in oxygenation in both normoglycemic and hyperglycemic fetuses. These observations may in part help explain the increased perinatal mortality in the pregnant woman with uncontrolled diabetes.

Sunshine exposure and serum 25-hydroxyvitamin D concentrations in exclusively breast-fed infants

The relationship between serum 25-hydroxyvitamin D (25-OHD) concentrations and sunshine exposure in 61 term, exclusively breast-fed infants younger than 6 months of age was investigated. Sunshine exposure was quantitated using a sunshine and clothing diary, which was verified by infant-adapted ultraviolet dosimetry. By multiple regression techniques, infant serum 25-OHD concentrations were significantly related to UV exposure and maternal serum 25-OHD concentrations. Infant 25-OHD concentrations correlated with sunshine exposure in infants whose mothers had low (less than 35 ng/ml) or high (greater than 35 ng/ml) serum concentrations of 25-OHD (r = 0.70, P less than 0.001 and r = 0.53, P = 0.004, respectively). Estimates were made to determine sunshine exposure conditions necessary to maintain serum 25-OHD concentrations above the lower limit of the normal range (11 ng/ml). A conservative estimate would be 30 minutes per week wearing only a diaper or 2 hours a week fully clothed without a hat.

Selective management of abruptio placentae: a prospective study

Antenatal diagnosis and selective management of abruptio placentae were studied prospectively over a 17-month period. Diagnosis was confirmed by placental inspection in 59 (1.3%) of 4545 deliveries. Among the 50 patients admitted with a living fetus, the diagnosis was made antenatally in 31 (62%). Fifteen were delivered vaginally and 16 by cesarean section. When these infants were compared to all other liveborn infants delivered during this period using a weight-adjusted chi 2 analysis, no significant difference was found in neonatal mortality or duration of hospitalization. There was a significant increase in the incidence of both respiratory distress syndrome and low Apgar scores among the study infants (P less than .005), but these increases were not correlated with mode of delivery or diagnosis-to-delivery interval. It is concluded that optimal fetal survival and an acceptable cesarean section rate may be obtained by selective management, especially in infants weighing more than 1500 g.

The effect of dexamethasone on the kinetics of jejunal zinc uptake and metallothionein synthesis in the rat

Several studies have linked hepatic metallothionein (MT) synthesis to changes in zinc metabolism in response to various forms of stress and to administration of glucocorticoid hormones. There is also some evidence that the intestinal absorption of Zn is enhanced under such conditions. The present studies were designed to investigate the effect of dexamethasone on the kinetics of Zn uptake in an isolated segment of the adult rat jejunum, perfused through the lumen and maintained in situ. Dexamethasone administered to adrenalectomized rats was found to affect significantly one of the parameters of the equation describing 65Zn uptake. Because the observed effect was kinetically consistent with an increased synthesis of MT in the jejunal mucosa, the synthesis of MT was monitored with 35S-cystine in both the liver and intestine of adrenalectomized rats given dexamethasone. Under these conditions, MT synthesis was significantly increased in the liver but not in the jejunal mucosa. The results indicate that dexamethasone is able to alter the kinetics of Zn uptake in the jejunum, but does so without increased jejunal MT synthesis.