Learning of a hiding task and a delayed response task in infant rhesus monkeys

The ability of the prefrontal cortex to learn was studied in 2-4-month-old male rhesus monkeys. Either the classical Delayed Response task with an opaque screen during the delay period or a Delayed Response task without a screen (the 'Hiding task') were performed every day beginning when the monkeys were 2 months old. The criterion for having learned the task was a correct performance rate of > 80% for two consecutive days. The Hiding task with a 0-s delay, training of which began at 50 days, was learned at 67 days. When the monkeys had reached 4 months of age, they were able to perform the Delayed Response task with a 3-s delay. During learning when the performance rate was low, monkeys tended to make perseverative errors, and tended to select the target position erroneously that was ipsilateral to the hand used. The rate of perseveration errors decreased linearly as the performance rate increased. Thus, 2-4-months-old monkeys in which synapses are produced in great abundance in the cortex, were capable of learning a Delayed Response task with a 3-s delay.

Plasma concentrations of betamethasone after topical application of betamethasone 17-valerate: comparison with oral administration

Plasma concentrations of betamethasone were measured by r.i.a. after oral administration of 0.6 mg betamethasone and topical application of betamethasone 17-valerate in the same five healthy subjects. Betamethasone 17-valerate was prepared as a suspension in medical grade pressure sensitive adhesive and applied to a 100 cm2 area on the back for 28 h. Mean maximum plasma concentrations were 5.0 and 0.24 ng ml-1 and mean AUC values were 75.4 and 7.74 ng ml-1 h after oral and topical administrations, respectively. The mean plasma elimination half-life of betamethasone after the removal of topical betamethasone 17-valerate was 16.6 h which was twice that after oral administration, 8.1 h. Betamethasone 17-valerate may require application to the skin more than twice daily.

Microautoradiographic study for the differentiation of intratumoral macrophages, granulation tissues and cancer cells by the dynamics of fluorine-18-fluorodeoxyglucose uptake

A substantial amount of macrophage infiltration occurs in both human and animal tumors. We previously showed that 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) uptake was higher in tumor-associated macrophages and young granulation tissues than in tumor cells. Differentiation of intratumoral non-neoplastic cells from neoplastic cells is important not only for the reduction of false-positives in FDG-PET tumor studies but also for patient management.

METHODS

A time-course study was performed using micro- and macro-autoradiography and tissue distribution in C3H/He mice bearing transplanted syngeneic FM3A mammary carcinoma and MH134 hepatoma was evaluated to analyze the intratumoral cellular dynamics of [18F]FDG and 2-deoxy-D-[3H]glucose in vivo.

RESULTS

The volume-doubling time in vivo was 1.3 days for MH134 and 4.9 days for FM3A, and the survival time of the host was 32.1 and 40.3 days, respectively. The peak uptake of both tracers in the tumor was 60 min after intravenous injection. The uptake by MH134 was 1.7-2.1 times higher than that by FM3A. The intracellular concentration as determined by counting the silver grains on micro-autoradiographic sections showed that the uptake by macrophages and focal small necrotic areas in both tumors was faster than the blood clearance until 15 min after tracer injection.

CONCLUSION

Thus, non-neoplastic cellular elements can be differentiated from viable neoplastic cells by means of the dynamic analysis of [18F]FDG uptake.

Role of laparoscopic cholecystectomy in treating gallbladder polyps

Since the application of laparoscopic cholecystectomy (Lap C) to gallbladder polyps has not yet been fully evaluated, we performed Lap C on 26 patients with gallbladder polyps. Pathological examinations showed adenocarcinoma in three patients, adenoma in two, and cholesterol polyp in 21. Preoperative diagnoses of the cases with adenocarcinoma were a cholesterol polyp in one patient and an adenoma in two. Adenocarcinoma was confirmed to reside in the mucosa without any invasion of lymphatic ducts or small vessels in the three patients. This procedure was considered to be sufficient for this grade of cancer, and, therefore, no additional operations were performed. At present, our policy is to resect by Lap C a gallbladder polyp having a maximum size larger than 10 mm and a tendency to grow or presenting with suspicion of adenoma. When cancer is suspected by preoperative examinations, however, traditional surgery may be recommended.

Recurrent dislocation of the patella in Turner's syndrome

We report two patients with Turner's syndrome who presented with recurrent dislocation of the patella (RDP). Both had a positive family history of patellar instability. The association of RDP with Turner's syndrome has not been reported previously. A subsequent study in 14 patients with Turner's syndrome demonstrated radiographical patellofemoral incongruency in eight patients, but no clinical manifestation of patellar instability. Although the present study suggests a possible link between Turner's syndrome and patellofemoral incongruency, it could not ascertain whether or not Turner's syndrome predisposes a patient to RDP.

Relocalization of Drosophila dorsal protein can be induced by a rise in cytoplasmic calcium concentration and the expression of constitutively active but not wild-type Toll receptors

The generation of dorso-ventral polarity in Drosophila relies on the formation of a nuclear gradient of the rel/nuclear factor kappa B transcription factor dorsal in the pre-cellular syncitial embryo by a process of differential nuclear localization. It is thought that the gradient is formed by activation at ventral positions of the membrane receptor Toll that in turn causes the local dissociation of dorsal from the cytoplasmic anchor protein cactus. Although Toll is related in its cytoplasmic domain to the interleukin-1 receptor little is known about the signal transduction pathways that lead from Toll to the relocalization of dorsal. In this paper we have used immunofluorescence microscopy as a direct assay of dorsal protein nuclear localization in the Drosophila cell line Schneider 2. We find that increased cytoplasmic calcium concentration and the expression of constitutively active Toll receptors can induce the relocalization of dorsal. By contrast, we find that activation of endogenous protein kinase A and expression of wild-type Toll receptors, which activate zen-chloramphenicol acetyltransferase reporter genes in this system, have only a marginal effect on the cellular distribution of the dorsal protein. Treatment of cells with activators of protein kinase C and radical oxygen intermediates, both of which activate nuclear factor kappa B, also has little effect on dorsal protein localization. We propose that different threshold levels of dorsal activation can be established by distinctly regulated signal transduction pathways.

[Epidemiological study on distribution of plaque, calculus and gingivitis among Nigerian people]

In 1991, dental health examination was carried out in Nigeria: ILE-IFE (urban) and Ashipa (rural) located in the southwest of Nigeria. The number of the subjects was 205 (aged 8, 10, 12) in ILE-IFE and 511 (aged 8, 10, 12, 15 to 75) in Ashipa. The purpose of this study is to clarify the distribution of plaque, calculus and gingivitis and to reveal the correlation between the plaque score (DI-S, OHI-S), calculus score (CI-S, OHI-S) and gingivitis score (GI) among the Nigerian by age. Results were as follows: 1. In the comparison between urban and rural schoolchildren, CI-S was higher in the rural children statistically but DI-S was not. This evidence is to be expected as a consequence of using PACO (traditional twig) for tooth brushing, because 73.1% of rural children were using the PACO whilst 92.1% of urban children were using the tooth-brush. 2. Because of the poor oral cleanliness using PACO, the changing pattern of DI-S, CI-S and GI by age could be natural and physiological. 3. DI-S and CI-S among the rural people were of a high level in the children 8 and 10 years of age and decreased to the bottom level in the 20's. After the lowest scores in the 20's, these increased with age. 4. The correlations between DI-S and GI were higher in the young people than in the elder people.

Dual sorption model for the nonlinear percutaneous permeation kinetics of timolol

The nonlinear percutaneous permeation kinetics of timolol were studied in vitro with human cadaver skin. In the sorption isotherm (equilibrium) study, the plots of the amount of timolol per unit area of epidermis versus aqueous timolol concentration in equilibrium were curvilinear as the dual sorption model predicts. In the penetration study, several aqueous timolol concentrations were maintained in the donor cell for 25 h. The lag-time was prolonged as the timolol concentration in the donor cell was decreased. The change in the lag time was analyzed by a newly proposed method with the lag-time prolongation factor that is calculated from the parameter values obtained in the sorption isotherm study. The ratio of the lag-time to lag-time prolongation factor was of the same magnitude, indicating that the dual sorption model explains the nonlinear percutaneous permeation kinetics of timolol. Finally, the diffusion parameter for the mobile solute was estimated by fitting the data of the cumulative amount excreted into receptor cell versus time to the numerical solution of the dual sorption model. The observed data were roughly compatible with the values predicted by the dual sorption model.

Evaluation of increased serum ferritin levels in patients with hyperthyroidism

To further elucidate the mechanism of increased serum ferritin levels in hyperthyroidism, the changes in erythrocytes and serum iron and total iron-binding capacity levels were examined in addition to serum ferritin levels in 13 hyperthyroid patients. The mean values of hemoglobin, red blood cells, and packed cell volume were increased by antithyroid therapy. While the serum levels of iron did not change, those of total iron-binding capacity increased significantly after achieving a euthyroid state. Increased serum ferritin levels returned to normal through antithyroid therapy. Furthermore, the serum ferritin levels of four anemic patients were significantly higher than those of nine nonanemic patients. Thus it is concluded that the increase in serum ferritin levels in patients with hyperthyroidism may be due to the direct action of thyroid hormones on its synthesis, while in some cases complicated with anemia impaired iron utilization by erythropoietic cells may also be involved.

[Radiotherapy and chemotherapy for locally advanced non-small-cell lung cancer: report of a clinical trial and review of the literature. South Osaka Lung Cancer Chemotherapy Study Group]

A prospective nonrandomized phase II trial was performed from June 1989 to Oct 1990 using concurrent chemotherapy and split course radiotherapy in the treatment of inoperable, locally advanced non-small-cell lung cancer (NSCLC). Eligibility criteria consisted of NSCLC, inoperable stage IIIA or IIIB excluding T3N0 or T3N1 of TNM classification, with pleural effusion, age 75 y.o. or less, PS0-2, with measurable lesion, previously untreated, normal bone marrow, adequate renal and hepatic function, PaO2 > or = 70 torr, and with no other active neoplastic disease. Patients were treated with 50 Gy of radiation in 25 fractions to the chest, together with 100 mg/m2 cisplatin and 8 mg/m2 mitomycin-C on day 1 and 29 and vindesine 3 mg/m2 on days 1, 8, 29, 36. Sixty-five patients were entered into this trial and 61 were eligible. There were 4 ineligible patients (1 stage II, 2 stage IV, 1 malignant lymphoma). Fifty-seven patients received 2 or more courses of chemotherapy, with dose modification in 42 patients. Only 5 patients received less than 50 Gy radiation dose. Fifty-three patients had a partial response for an overall response rate of 87% (95% CI 78-95%). Median duration of response was 276 days. Median survival time (MST) was 450 days. One, 2, and 3 year survival were 60%, 37%, and 28%, respectively. In IIIa (13 patients), MST was 358 days and 1, 2, and 3 year survival were 50%, 50%, and 42%, respectively. In IIIB (48%), MST was 450 days and 1, 2, and 3 year survival were 63%, 33%, and 25%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of single oral dose of sodium benzoate on ureagenesis in healthy men and two patients with late onset citrullinaemia

Although sodium benzoate therapy is beneficial in patients with inborn error of urea cycle, it has been suggested that an accumulation of benzoyl-CoA would inhibit ureagenesis. In this study, we examined several aspects of ureagenesis after the single oral dosing of sodium benzoate in six healthy subjects who participated in the study previously reported and in two patients with citrullinaemia. Urea nitrogen appearance (UNA) did not change after the doses of 40, 80 and 160 mg.kg-1 of sodium benzoate in the 6 healthy subjects. Sum of UNA and urinary hippurate nitrogen (UHN) increased with increasing the dose. In the 2 patients with late-onset citrullinaemia who benefit from a partially functional urea cycle, no apparent inhibitory effects on the UNA were observed after the administration of 80 mg/kg of sodium benzoate. The precursors of urea (ammonia, glutamate, glutamine and alpha-amino nitrogen) did not increase after the benzoate administration in the 6 normal subjects as well as in the 2 patients with citrullinaemia.

[Chronic type hypersensitivity pneumonitis]

The clinical features and chest X-ray appearances of chronic type hypersensitivity pneumonitis closely resemble those of idiopathic interstitial pneumonia. Therefore, it is very difficult to make a correct diagnosis without detailed information. Our study showed that bronchoalveolar lavage and lung biopsy are useful examinations for the differential diagnosis of these two diseases. The characteristic finding of bronchoalveolar lavage of chronic type hypersensitivity pneumonitis is still lymphocytosis, as is also seen in the acute type. The pathological findings of chronic type hypersensitivity pneumonitis are alveolitis with marked lymphocyte infiltrations and granuloma formation although the number of granulomas is low. Recently, we experienced five patients with chronic type farmer's lung. The average age of these five patients was significantly older than that of acute type farmer's lung. They had engaged in farming after the onset of their disease, which suggested continuous chronic exposure to mouldy hay. It is concluded that patients with hypersensitivity pneumonitis, especially aged people, should avoid antigen exposure and should be followed up the progress of the disease with intensive care.

A comparative study on protein incorporation of L-[methyl-3H]methionine, L-[1-14C]leucine and L-2-[18F]fluorotyrosine in tumor bearing mice

Brain and tumor uptake of L-[methyl-3H]methionine (3H-Met), L-[1-14C]leucine (14C-Leu) and L-2-[18F]fluorotyrosine (18F-Tyr) and their incorporation into the acid-precipitable fraction (APF) were investigated in mice bearing FM3A-P0 and the higher metastatic FM3A-P15A mammary carcinomas in order to compare the potential of positron emitting analogs for measuring protein synthesis rates (PSR) in brain and tumors by positron emission tomography (PET). The total uptake of the 3H-Met by the brain was higher than those of two other amino acids. On the other hand, the incorporation rates into the APF in the brain and tumors were significantly faster with 14C-Leu compared to the others. Most of the 14C in the APF was identified in labeled proteins; however, considerable amounts of 3H were recovered in the lipid and RNA fractions, and 18F was also detected in the lipids. Among the positron emitting analogs of three amino acids, 11C-labeled Leu could be the most suitable for measuring PSR by PET. For all the amino acids, the total uptake and the APF both expressed as the % injected dose seemed slightly higher in the FM3A-P15A than in the FM3A-P0, although the differences did not reach statistical significance.

Antithrombin III producing hepatocellular carcinoma

A case of primary hepatocellular carcinoma with an abnormal increase in the antigenic quantity and activity of Antithrombin III (AT-III) is reported. The patient was a 53-year-old man. The liver was palpated for a five fingerbreadths, but no jaundice or ascites was noted. Computed tomogram (CT) revealed the presence of many nodules of various sizes in the right hepatic lobe. Both viral markers of HBV and HCV were negative. For tumor markers, PIVKA-II was high (27.7 AU/ml) but AFP was normal. Among coagulation and fibrinolytic factors, the activity and antigenic levels of AT-III were abnormally high (290% and 81.6 mg/dl). An US guided needle biopsy of the tumor revealed hepatocellular carcinoma, Edmondson I. The cellularity was high and the tumor cells were small, well differentiated. The tumor cells were positively stained in immunohistochemical staining using the anti-AT-III antibody. It was believed that AT-III produced by the tumor cells was responsible for this exaggerated level.

General pharmacology of the non-sulfhydryl angiotensin converting enzyme inhibitor N-[8-amino-1(S)-carboxyoctyl]-L-alanyl-L-proline

The effects of N-[8-amino-1(S)-carboxyoctyl]-L-alanyl-L-proline (AB-47, CAS 120008-53-9), an orally active angiotensin converting enzyme inhibitor, on the central nervous, respiratory and cardiovascular, autonomic systems, isolated smooth muscles and other functions were investigated in various experimental animals. AB-47 had no effect on central nervous, autonomic systems and isolated smooth muscles. AB-47 (10 and 30 micrograms/kg i.v.) significantly lowered femoral blood pressure without affecting respiration and heart rate in anesthetized rats. However, AB-47 had no effect on the contractile tension of mammalian isolated atrium and aorta. AB-47 had no effect on gastrointestinal transit in mice. Very slight injury of gastric mucosa was observed 4 h after the oral administration of AB-47 in rats but AB-47 did not damage the small intestinal mucosa. AB-47 had no effect on the contraction of rat phrenic nerve-diaphragm preparation induced by electrical stimulation. AB-47 did not affect the incidence of acetic acid-induces writhings. AB-47 potentiated carrageenan-induced hind paw edema in rats. The potentiation of edema may be due to an accumulation of bradykinin induced by the inhibition of angiotensin converting enzyme (ACE), because ACE is the identical enzyme with kinase II. The pretreatment of AB-47 for 7 days (1, 3, 10 mg/kg/d p.o.) inhibited the cardiac hypertrophy induced by isoproterenol (isoprenaline). This result suggests that the renin-angiotensin-aldosterone system directly or indirectly participates in the cardiac hypertrophy induced by isoproterenol.(ABSTRACT TRUNCATED AT 250 WORDS)

Alterations in respiratory function and hemodynamics during laparoscopic cholecystectomy under pneumoperitoneum

Respiratory function and hemodynamics were studied during laparoscopic cholecystectomy (LC) under a 10 mmHg pneumoperitoneum (PP) by carbon dioxide insufflation. Blood-gas analysis and measurement of cardiac function by using a Swan-Ganz catheter were performed. Creatinine clearance rate was measured preoperatively and intraoperatively. Compared with values obtained before the institution of PP, blood-gas analysis showed a significant increase in PCO2 (P < 0.01), and a significant decrease in pH (P < 0.01) and base excess (P < 0.05) during PP. With respect to cardiac function, there was no significant change in cardiac output, pulmonary arterial pressure, and pulmonary arterial wedge pressure. Intraoperative creatinine clearance rate (Ccr) was decreased in 29 of 48 cases, increased in 18 cases, and unchanged in 1 case, resulting in no significant difference overall between the values measured preoperatively and intraoperatively. However, in eight individual cases, the Ccr was found to have decreased significantly. Although alterations in respiratory function were observed, LC at 10 mmHg PP did not cause any crucial problems in respiratory or cardiac function. It should be kept in mind, however, that renal blood flow may decrease in some cases even at intraabdominal pressures under 10 mmHg.

Re-evaluation of amino acid PET studies: can the protein synthesis rates in brain and tumor tissues be measured in vivo?

The significance of L-[methyl-11C]methionine (11C-Met), L-[1-11C]leucine (11C-Leu) and L-2-[18F]fluorotyrosine (18F-Tyr) for measuring protein synthesis rates in the brain and in tumors by PET was re-evaluated. Tissue uptake and protein incorporation of 3H-Met, 14C-Leu and 18F-Tyr were investigated in mice bearing the FM3A mammary carcinoma. In the control group, the uptake of all three tracers in the brain and FM3A and their incorporation into the acid-precipitable fraction (APF) increased over 60 min. When the protein synthesis in vivo was inhibited by cycloheximide, the incorporation of all three tracers into the APF was significantly reduced to 6%-32% and 3%-11% of the control in the brain and FM3A, respectively. Under these conditions, total uptake of 14C-Leu in the brain and FM3A decreased rapidly, and most of the 14C in the APF was detected as proteins. On the other hand, 3H-Met and 18F-Tyr uptake continued to increase, and significant amounts of radioactivity were incorporated into nonprotein materials. In mice given ouabain to inhibit amino acid transport, total uptake of all three amino acids by FM3A was reduced to 67%-74% of the control 5 min postinjection. These results demonstrate that uptake of the three amino acids is affected by alterations in the amino acid transport system in the brain and tumor tissues, but that only 14C-Leu uptake reflects protein synthesis rates.

Delay-related activity in the primate prefrontal cortex during sequential reaching tasks with delay

To investigate how prefrontal neurons store multiple spatial locations simultaneously, neuronal activity during delay was analyzed while a monkey performed a delayed sequential reaching (DSR) task, in which the monkey was required to store both locations and the order of two sequentially presented targets during delay, and a delayed reaching (DR) task with single target. 38 out of 61 task-related neurons showed delay-related activity and were classified into three types. Type 1 (58%) showed delay-related activity depending upon the direction of the first reaching movement. Type 2 (21%) showed delay-related activity depending upon whether the reaching cue was presented at either left or right. Type 3 (21%) showed delay-related activity nonspecifically during all trials of both DSR and DR. Neurons with delay-related activity only in DSR trials were not observed. These results suggest that each prefrontal neuron may not hold information for the whole sequence of a complex movement during delay, but may hold partial information of that movement, such as one target location or one movement direction.

[A case of metastatic spinal tumor from renal cancer reduced by interferon-alpha]

A case of metastatic spinal tumor from renal cancer reduced by interferon-alpha is reported. A 54-year-old man was admitted to Tane General Hospital on April 12, 1990, with the complaint of difficulty in walking. Abdominal CT scan revealed right renal carcinoma, and MRI demonstrated metastatic spinal tumor at Th6, which was mainly occupying the entire lamina, spinous process and right pedicle of Th6. Nephrectomy was performed and, instead of operating on the spinal lesion, the patient was given follow-up treatment with administration of interferon-alpha (5 million units twice a week) and steroid. 1 year and 6 months later the patient's walking ability began to deteriorate and paraparesis progressed, although the size of the metastatic spinal tumor had gradually reduced. This was thought to be because of atrophy of the legs due to prolonged bed rest and steroid administration. Laminectomy with total removal of the tumor was performed on January 16, 1992. In the 12 months postoperatively, there has been neither recurrence nor remote metastasis seemingly due to the administration of interferon-alpha. This appears to be the first report of metastatic spinal tumor from renal cancer reduced by interferon-alpha.

[Effect of G-CSF and M-CSF on busulfan-induced marrow failure in a 91-year old patient with essential thrombocythemia]

A 91-year-old patient with essential thrombocythemia presented with marked bone marrow suppression induced by long-term administration of busulfan. Her pancytopenia extended for over two months even after the cessation of busulfan, suggesting that she had developed a severe decrease in hematopoietic reserve. We administered G-CSF and M-CSF to accelerate recovery from marrow failure and to evaluate the recovery of hematopoiesis. The standard doses of G-CSF and M-CSF increased her neutrophil and platelet counts sufficiently but only transiently. Transient eosinophilia was also noted after cessation of M-CSF. The possibility that the expansion of abnormal clone(s) induced the transient increase in platelet and eosinophil counts could not be completely excluded. We suggest that the administration of hematopoietic growth factors should be limited to patients, irrespective of age, who present marked clinical symptoms attributable to marrow failure when the patient has a chronic myeloproliferative disorder.

Lipoma arborescens with hemarthrosis of the knee. A case report

Lipoma arborescens is a rare intraarticular lesion, typically with a clear yellow aspirate. We report a case of lipoma arborescens with hemarthrosis of the knee.

A prospective phase II study on photodynamic therapy with photofrin II for centrally located early-stage lung cancer. The Japan Lung Cancer Photodynamic Therapy Study Group

PURPOSE

A phase II study was conducted between June 1989 and February 1992 to evaluate the activity and toxicity of photodynamic therapy (PDT) with photofrin II in centrally located early-stage lung cancer and to determine the complete response (CR) rate as the primary end point.

PATIENTS AND METHODS

Patients had histologically proven lung cancer and endoscopically superficial thickening or small protrusions. All lesions were located in subsegmental or larger bronchi. All patients had a performance status (PS) of 0 to 2 and arterial oxygen pressure tension (PaO2) > or = 60 mm Hg. No lymph node or distant metastases were present. All patients received photofrin II (2 mg/kg) intravenously 48 hours before PDT. Tumor lesions were superficially photoradiated by an argon dye laser or an excimer dye laser.

RESULTS

Of 54 patients with 64 carcinomas, 51 with 61 carcinomas were eligible for toxicity evaluation and 49 with 59 carcinomas were assessable for response. Of the 59 assessable carcinomas, 50 (84.8%; 95% confidence interval, 73.0% to 92.8%) showed a CR after initial PDT. The median duration of CR was 14.0+ months (range, 2.0+ to 32.4+). The multiple regression model indicates that estimated length of longitudinal tumor extent was the only independent prognostic factor for CR (P = .002). Five carcinomas that had a CR had a local recurrence at 6, 10, 12, 16, and 18 months after initial PDT, respectively. Toxicity assessment (World Health Organization [WHO] grade 2) showed transient elevation of ALT (1.9%), pulmonary toxicity (7.7%), and allergic reaction (7.7%), as well as sunburn (1.9%).

CONCLUSION

PDT with photofrin II has an excellent effect on patients with centrally located early-stage lung cancer who have limited tumor invasion extending over a small area (< or = 1 cm).

In vitro percutaneous permeation of betamethasone and betamethasone 17-valerate

The percutaneous permeation and sorption isotherm (equilibrium) profiles of betamethasone and betamethasone 17-valerate were estimated in an in vitro study with excised human skin. Corticosteroids were measured by HPLC. The stratum corneum (dry weight)/water partition coefficient of betamethasone 17-valerate was 20 times greater than that of betamethasone. Nevertheless, when aqueous saturation was maintained in the donor solution, the mean steady-state flux of betamethasone 17-valerate through split-thickness skin was 57.6 ng/cm2/h, whereas that of betamethasone was 15.2 ng/cm2/h. This was presumably because the aqueous saturation concentration of betamethasone (60 micrograms/mL) was 11 times greater than that of betamethasone 17-valerate (5.4 micrograms/mL), so that the calculated saturation concentrations of the two corticosteroids in stratum corneum were within a factor of 2. However, the drug amounts or concentrations of the more lipophilic corticosteroid (betamethasone 17-valerate) attained in viable layers (viable epidermis and dermis) at steady state were predicted to be greater than those of the less lipophilic corticosteroid (betamethasone) when the results in the permeation and equilibrium studies were interpreted by a mathematical model. The drug distribution pattern predicted (i.e., that a more lipophilic corticosteroid preferentially partitions into viable layers) was reasonable when compared with that observed in the permeation study. The mean drug amount of betamethasone 17-valerate in dermis was four times greater than that of betamethasone, whereas the drug amounts of both corticosteroids in epidermis were similar to each other.