Comparative study of attitudes to eating between male and female students in the People's Republic of China

OBJECTIVE

This study was conducted to compare eating attitudes and lifestyles of male and female college students in China (Beijing).

SUBJECTS AND METHODS

The subjects of this study consisted of 217 male and 177 female college students. They were asked to fill out the Eating Attitudes Test-26 (EAT-26) and a lifestyle questionnaire.

RESULTS

The percentages of those above the cutoff point on the EAT-26 for abnormal eating attitudes were 4.7% of male and 6.2% of female students. Body perception of being fat (distorted body image) was the factor most associated with abnormal eating attitudes.

DISCUSSION

Weight related concern was prevalent amongst the Chinese students. This suggests that the culture of the beauty of thinness is common among young students in Beijing, particularly female students.

Factors associated with abnormal eating attitudes among female college students in Japan

OBJECTIVES

To determine the prevalence rates of abnormal eating attitudes and associated risk factors among female Japanese college students.

SUBJECTS AND METHODS

The study population was 7812 female college students in Tokyo. They were asked to fill out the Japanese version of EAT-26 and lifestyle questionnaires.

RESULTS

5.1% of the subjects had a total EAT-26 score above the cutoff point (>20). Multiple regression analysis found the most important factors associated with abnormal eating attitudes were distorted body image, fewer sleeping hours, irregular meal habits, cigarette smoking and more exercise.

DISCUSSION

The prevalence of abnormal eating attitudes among female college students in this study was lower than that of Japanese female high school students and lower than that reported for college students of both western and non-western countries. Our results suggest that body image dissatisfaction may be the most important factor associated with abnormal eating behavior.

Demonstration of Inter- and Intracellular Distribution of Boron and Gadolinium Using Micro-Proton-Induced X-Ray Emission (Micro-PIXE)

Micro-proton-induced X-ray emission (Micro-PIXE) was applied to determine inter- and intracellular distribution of boron (10B) and gadolinium (157Gd), the capture atoms used to kill tumor cells in neutron capture therapy (NCT). Cultured 9L gliosarcoma cells on Mylar film were exposed to sodium borocaptate (BSH) and gadobenate dimeglumine (Gd-BOPTA). To analyze the inter- and intracellular distribution of 10B and 157Gd in 9L gliosarcoma cells, the cells were irradiated using a proton beam of 1.7 or 3 MeV energy collimated to 1 microm diameter and emission X-ray was detected. The distribution of 10B and 157Gd in 9L gliosarcoma cells was then examined. In this study, we could directly analyze the inter- and intracellular distribution of 10B and 157Gd elements in 9L gliosarcoma cells directly using Micro-PIXE. This is the first report on the distribution of 10B employing a method to detect gamma-rays resulting from the nuclear reaction of 10B using particle-induced gamma-ray emission (PIGE). These results show that the distribution of 157Gd elements was correctly measured using micro-PIXE. 157Gd should have the same tendency as 10B in cultured 9L gliosarcoma cells and agree with the distribution in 9L gliosarcoma cells. Further investigation is necessary for a higher spatial resolution and optimization of the measurement time or improvement of the sampling method. In the future, it will be possible to employ this method to analyze the intracellular microdistribution of the capture element and in the development of new drugs for NCT.

Laparoscopic Heller myotomy and Dor fundoplication for the treatment of achalasia

BACKGROUND

The significance of laparoscopic Heller myotomy and Dor fundoplication (LHD) for the treatment of achalasia in relation to the severity of the lesion has not been sufficiently assessed.

METHODS

Of patients who were diagnosed with achalasia from August 1994 to February 2004, 55 individuals who underwent LHD served as subjects. The therapeutic effects of LHD were assessed in terms of operation time, intraoperative complications, postoperative hospital stay, and symptom improvement in relation to morphologic type (spindle type, Sp; flask type, Fk; and sigmoid type, Sig). Degree of symptomatic improvement was classified into four grades: excellent, good, fair, and poor.

RESULTS

Breakdown of morphologic type was as follows: Sp, n = 29; Fk, n = 18; and Sig, n = 8. Excluding one patient for whom conversion to open surgery was required, median average operation time for 54 patients was 160 min. As to intraoperative complications, esophageal mucosal perforation was seen in nine of the 55 patients (16%); however, conversion to open surgery could be avoided by suturing the affected area. Moreover, intraoperative bleeding of at least 100 g was seen in five of the 55 patients (9%), with one Fk patient requiring conversion to open surgery and transfusion. Median postoperative hospital stay was 8 days. Degree of dysphagia relief was excellent in 45 patients (83%), good in eight patients (15%), and fair in one patient (2%). Excellent improvement was obtained in 90%, 88%, and 50% in Sp, Fk, and Sig patients, respectively. Reflux esophagitis was seen in two patients, and was treated with a proton pump inhibitor.

CONCLUSIONS

The results of the present study suggest that classification of morphologic type is a useful parameter in predicting postoperative outcome in achalasia. In order to achieve excellent symptomatic relief, surgery for achalasia should be recommended for but not limited to Sp and Fk types.

Multivariate analysis of risk factors for hemorrhagic cystitis after hematopoietic stem cell transplantation

To establish the most appropriate prophylactic therapy and risk factors for predicting hemorrhagic cystitis (HC) after stem cell transplantation (SCT), we retrospectively analyzed the clinical records of 450 transplant patients treated from 1982 to 2002. In all, 81 patients developed early- and/or late-onset HC (early=29, late=48, both=4). For the incidence of early-onset HC, administration of cyclophosphamide (CY) (p=0.0079, odds ratio (OD)=5.109, 95% confidence interval (CI)=1.533-17.030), busulfan (BU) (p=0.0015, OD=3.336, 95% CI=1.584-7.027), BU+CY (p=0.0001, OD=4.369, 95% CI=2.055-9.292), antithymocyte globulin (p=0.0009, OD=3.368, 95% CI=1.642-6.911), nonradiation (p=0.0163, OD=2.564, 95% CI=0.181-0.841), 2-mercaptoethane sodium sulfonate (Mesna) (p=0.0001, OD=7.519, 95% CI=2.847-19.858), and bladder irrigation (p=0.0001, OD=4.950, 95% CI=2.328-10.523) were risk factors. By Fisher's exact test, the combination of BU and Mesna was a more significant risk factor (P<0.001) than Mesna alone (p=0.008) compared to the administration of neither agent. By multivariate analysis, prophylactic administration of Mesna (p=0.0105, OD=5.301, 95% CI=1.477-19.026) and bladder irrigation (p=0.0001, OD=9.469, 95% CI=3.872-23.156) were significant risk factors of early-onset HC. We conclude that (i). high-dose BU as well as CY is a cause of HC, (ii). protective bladder irrigation has an opposite effect, and (iii). Mesna possibly has a toxic effect on bladder mucosa.

Dose measurement for patients and physicians using a glass dosemeter during endovascular treatment for brain disease

It has been reported that exposure of patients and physicians to radiation from interventional radiological procedures cannot be disregarded. Direct measurement of patient exposure used to be difficult due to possible interference by the detector with the observation of X ray images. Recently, a dosemeter system consisting of small-sized glass chips and a reader which adopts pulsed UV laser stimulation has been developed. Owing to its small size, radiolucency and physical characteristics, direct monitoring of surface dose has become feasible. Dose measurement for patients and physicians during neurointervention was done using the photoluminescence glass dosemeter system. The dose-response of the dosemeter was almost linear over a broad dose range, but its energy dependency was rather high without a filter, the use of which is recommended by the manufacturer to compensate for energy dependency. Variation of sensitivity of about 20% was observed for effective energies of 45-60 keV which are used in neurointervention. In spite of this shortcoming, the photoluminescence glass dosemeter system was judged to be a convenient means for monitoring dose during neurointervention.

Role of (111)In-DTPA-pentetreotide scintigraphy in accurate diagnosis of neuroendocrine gastroenteropancreatic tumors

Most gastroenteropancreatic neuroendocrine tumors contain high-affinity binding sites for somatostatin, and somatostatin-receptor scintigraphy has been introduced for the in-vivo evaluation of such tumors. We report two patients with gastroenteropancreatic neuroendocrine tumors, in whom it was quite difficult to localize the tumors by conventional techniques, and in whom we found that (111)In-DTPA-pentetreotide scintigraphy was useful for accurate information on tumor localization. In the first patient, who had gastrinoma, multiple tumors were shown in the gastrinoma triangle, but we could not clarify whether there were any tumors in the pancreatic body. The selective arterial secretin injection (SASI) test diagnosed that the gastroduodenal artery was the feeder of the gastrinomas, and (111)In-DTPA-pentetreotide scintigraphy with single-photon emission computed tomography indicated the absence of tumors in the pancreatic body. In the second patient, who had insulinoma, multiple liver tumors and a large mass in the hilum of the spleen were shown. (111)In-DTPA-pentetreotide scintigraphy was useful in determining that there was no secretion of insulin from the tumor in the hilum of the spleen. In conclusion, X-ray computed tomography is superior for detection of neuroendocrine tumors, because not all neuroendocrine tumors have somatostatin receptors; however, somatostatin receptor scanning, as well as the SASI test, may be useful for the surveillance of patients with known primary tumors, for monitoring patients with disseminated disease, and for following the treatment of these patients.

Expression of endothelial cell-associated molecules in AML cells

Recently, it has been clarified that interaction between hematopoietic cells and endothelial cells is important in normal hematopoiesis and leukemogenesis. In this study, we examined the relationship between AML cells and endothelial cells by analyzing the expression profile of angiogenic factors, angiopoietin-1 (Ang-1), Ang-2, Tie-2 (a receptor for angiopoietins) and vascular endothelial growth factor (VEGF). Our results demonstrated that CD7(+)AML expressed Ang-2 mRNA frequently and integrin-family adhesion molecules (CD11c and CD18) intensively, suggesting the close correlation with endothelial cells. On the other hand, in t(8;21) AML cells, expression of Ang-2 was infrequent and expression of integrin-family adhesion molecules (CD11b, CD11c and CD18) was weak, suggesting the sparse association with endothelial cells. As for CD7(+)AML cells, despite the frequent and intense expression of endothelial cell-associated molecules (such as Ang-2, CD11c and CD18), intensity of Tie-2 expression was quite low (P < 0.05). Ang-2 expressed in CD7(+)AML cells is not considered to act in an autocrine fashion, but to work on endothelial cells to "feed" leukemic cells. Although Ang-2 is recognized as a natural antagonist for Tie-2, our data presented here suggested the alternative role of Ang-2 in the relationship between endothelial cells and leukemia cells, at least in a subset of leukemia such as CD7(+)AML. These results were supported by the study using AML cell lines, KG-1 (CD7 negative) and its subline KG-1a (CD7 positive); KG-1 had mRNA expression profile of Ang-1(+)Ang-2(-)Tie-2(+), while KG-1a showed Ang-1(+)Ang-2(+)Tie-2(-). These difference in the expression profile of angiogenic factors between CD7(+)AML and t(8;21)AML may explain the characteristic morphological features of these leukemias (CD7(+)AML as blastic type and t(8;21)AML as differentiative type).

Phospholipid alterations in hepatocyte membranes and transporter protein changes in cholestatic rat model

Biliary components are transported by hepatic adenosine triphosphate-binding cassette (ABC) transporters that are located in canalicular membranes. Physiological transporter function is related to membrane fluidity, which is modulated by the phospholipid composition of the lipid bilayer. We hypothesized that cholestasis may alter transporter function by modifying phospholipid species to protect the cell from cholestatic damage. Therefore, we examined the expression of ABC transport proteins and their mRNA levels in canalicular membrane vesicles isolated from rat liver 6 hr or three days after bile duct ligation. Membrane lipid composition and membrane fluidity of both sinusoidal and canalicular membrane vesicles were also examined. By 6 hr after bile duct ligation, we found a clear increase of mdr2 and bsep mRNA. These changes were associated with an increase of mdr-Pgp and with a clear decrease of mrp2 protein, and small decrease of bsep protein. In addition, mdrlb mRNA showed a strong increase by three days after bile duct ligation. Canalicular membrane fluidity decreased in a marked time-dependent manner, whereas sinusoidal membranes showed biphasic changes: increased fluidity at 6 hr and a decrease at three days. These changes were closely related to the changes of membrane lipid constitution; the saturated/unsaturated fatty acid ratio increased for phosphatidylcholine in canalicular membrane and the reverse occurred in sinusoidal membrane, and those for sphingomyelin showed the opposite pattern. We conclude that cholestasis causes modulation of ABC transporters as well as that of the lipid constitution in lipid bilayer. These may confer cytoprotective resistance to hepatocytes against cholestatic stress.

Pituitary apoplexy caused by luteinizing hormone-releasing hormone in prolactin-producing adenoma

We report a case in which pituitary apoplexy developed shortly after an intravenous (i.v.) injection of luteinizing hormone-releasing hormone (LH-RH). A 56-year-old man with prolactin-producing pituitary tumor complained of severe headache, visual field loss and facial nerve palsy shortly after LH-RH test. Magnetic resonance image (MRI) revealed a hemorrhage in the pituitary adenoma. He showed dramatic improvement in his symptoms after decompression surgery. These findings suggest a causal relationship between the i.v. injection of LH-RH and pituitary apoplexy. Possible pituitary apoplexy should be kept in mind during pituitary testing.

[Panic disorder and antidepressants]

Anxiety disorders, specifically, panic disorder, are the most common mental health disorders. Unless the clinician has a high index of suspicion, panic disorder or social anxiety disorder may remain undetected. Although quality of life(QOL) issues have long been recognized in severe psychiatric disorders, they have only recently come to be considered for the anxiety disorders. While the older tricyclic antidepressants(TCAs) are efficacious in the treatment of theses anxiety disorders, recent studies with paroxetine and other selective serotonin reuptake inhibitors(SSRIs) have emphasized the role of serotonin in the aetiology of these conditions. Both the TCA and SSRI antidepressants are effective in treating a wide variety of anxiety disorders. SSRIs, due to their greater safety and tolerability, should be the preferred choices in treating anxiety disorders in those instances.

Intraosseous meningioma of the posterior fossa--Case report

A 62-year-old male presented with a rare intraosseous meningioma with intradural extension manifesting as frequent vomiting and floating sensation that had persisted for 3 months. Neuroimaging detected a mass lesion that was mainly located extradurally in the right posterior fossa with a daughter lesion inside the dura. He underwent surgical excision of the mass lesion. Craniectomy exposed the main lesion of the tumor just beneath the thinned outer table of the skull, and in the extradural space, with the daughter lesion penetrating the dura. Both portions of the tumor were resected. There was no attachment to the adjacent dura mater. Histological examination showed meningotheliomatous meningioma containing scattered bony tissue. This intraosseous meningioma probably originated from the occipital bone with a small intradural extension caused by mechanical compression.

[Secondary eosinophilia in a patient with hypereosinophilic syndrome after allogeneic bone marrow transplantation from a sibling donor]

A 23-year-old man first visited a local hospital in 1998 because of exertional dyspnea. Peripheral blood examination revealed mild leukocytosis with 82% eosinophils, and he was treated with prednisolone. As the eosinophilia did not improve, he was referred to Tokai University Hospital in March 1999 for further diagnosis and treatment. The patient was diagnosed as having hypereosinophilic syndrome (HES) because of unexplained hypereosinophilia persisting for more than 6 months, resulting in cardiac dysfunction. His disease was progressive in spite of immunosuppressive therapy, interferon-alpha and cytotoxic chemotherapy. Since he had an HLA-identical brother, allogeneic bone marrow transplantation (BMT) was performed in October 1999. After completion of the immunosuppressive therapy on day 79 after BMT, the number of eosinophils gradually increased again. Although we suspected recurrence of the disease, DNA fingerprinting revealed that the peripheral granulocytes were 100% donor type. An increase of interleukin-5 (IL-5) produced by peripheral lymphocytes and a decrease of the Th1/2 ratio suggested that the eosinophilia was related to GVHD. The eosinophilia was eventually controlled by cyclosporin. We conclude that DNA fingerprinting and examination of the IL-5 level and Th1/2 ratio are useful for differentiating between relapse and GVHD in cases of eosinophilia occurring after BMT for HES.

Dose-dependent conjugation of sulfobromophthalein and hepatic transit time in bile fistula rats: role of the microtubule-dependent vesicle pathway

Sulfobromophthalein (BSP) is selectively taken up by the liver and secreted into the bile as unconjugated and conjugated forms. Our previous study demonstrated that unconjugated BSP, but not conjugated BSP, caused the dissociation of biliary lipid secretion from that of bile acids, suggesting that the hepatic BSP conjugation rate partly regulated biliary lipid secretion. To evaluate the mechanisms through which biliary lipid secretion is regulated by exogenous organic anions, we intravenously administered BSP to male Sprague-Dawley rats at various doses either continuously or as a bolus. Then the relationship of the dose of BSP to its conjugation rate, hepatic transit time, and biliary lipid secretion was determined. BSP decreased biliary secretion of cholesterol and phospholipids in a dose-dependent manner without affecting bile acid secretion. In contrast, the proportion of conjugated BSP in bile was associated with the dose. Although the serum clearance of BSP after bolus infusion was constant regardless of the dose administered (50 or 200 nmol/100 g), BSP secretion was delayed with increasing doses: unconjugated BSP was secreted predominantly in the early phase (0-15 min after bolus injection), and conjugated BSP was the predominant form in the late phase (15-30 min). Pretreatment with colchicine reduced the conjugation rate and hepatic transit time of BSP, suggesting that the microtubule-dependent vesicle pathway plays a role in biliary excretion and conjugation of BSP. We conclude that biliary lipid secretion is influenced by organic anions with an affinity for bile acids such as BSP and that this effect is dependent upon the hepatic metabolic rate, i.e., conjugation rate. The hepatic transit time also plays a key role in this process by influencing metabolism.

[Reproduction physiology and prostanoids]

Prostanoids, which consist of prostaglandins (PGs) and thromboxane, are produced from arachidonic acid by cyclooxygenases (COXs) as a rate-limiting step, and they exert various biological actions. Classically, prostanoids are suspected to be closely related to female reproductive processes such as ovulation, luteolysis and uterine contraction, as well as pathological processes such as fever generation and pain modulation. Recently the cDNA cloning of a series of prostaglandin-synthesizing enzymes and receptors enabled us to clarify which isoform or subtype is involved in each reproductive process by generating individual gene-deficient mice. In late pregnancy, PGF2 alpha synthesized by COX-1 is essential for induction of parturition via luteolysis. Furthermore, impaired induction of COX-2 in the myometrium of PGF2 alpha receptor-deficient mice is accompanied with loss of parturition, suggesting that COX-2 is presumably responsible for producing uterotonic PGs. In early pregnancy, PGE2 synthesized by COX-2 induces the expansion of cumulus cells through EP2 receptor and contributes to ovulation and fertilization. These results may be useful in not only developing novel drugs in the reproductive area but also understanding and overcoming harmful reproductive side effects of classical and novel drugs in non-reproductive areas.

Improvement of splenomegaly and pancytopenia by enzyme replacement therapy against type 1 Gaucher disease: a report of sibling cases

Gaucher disease is a genetic lipid storage disease and represents a potentially serious health problem. It arises from a deficiency of glucocerebrosidase activity with secondary accumulation of large quantities of glucocerebroside. Symptoms are usually multisystemic, often debilitating or disabling, and sometimes disfiguring, and they can lead to death. We report objective clinical response's to repeated infusion of human placental and recombinant glucocerebrosidase in 2 patients with type 1 Gaucher disease and increased hemoglobin levels and platelet counts. Splenic volume decreased during the period of enzyme administration. Enzyme replacement therapy has improved the treatment of type 1 Gaucher disease by safely and effectively arresting, decreasing, or normalizing many of its major signs and symptoms. Consideration by physicians must be given to Gaucher disease, and appropriate treatments must be given when confronted with cryptogenic pancytopenia or hepatosplenomegaly.

Effects of amlodipine on serum levels of adrenal androgens and insulin in hypertensive men with obesity

We investigated the effects of the calcium channel blocker amlodipine besilate on serum levels of adrenal androgens and insulin in 20 men with essential hypertension and obesity (age: 51.9+/-4.7 years, body mass index: 27.7+/-1.5 kg/m2). All were treated with amlodipine besilate (Norvasc) for 3 months. Blood pressure, fasting plasma glucose (FPG), HbA1c and serum levels of insulin, dehydroepiandrosterone (DHEA), DHEA sulfate (DHEA-S), and lipids were measured before and after a 3-month period. In 10 patients, 75 g oral glucose tolerance test (75 g-OGTT) was also performed. Amlodipine besilate treatment 1) lowered the fasting serum insulin level and total serum insulin level during 75 g-OGTT and 2) increased serum DHEA and DHEA-S levels. No changes in fasting plasma glucose, HbA1c and serum lipids were observed during treatment. We conclude that amlodipine besilate improves insulin resistance and consequently increases serum DHEA and DHEA-S levels.

Fibroblast growth factor-2-producing fibroblasts protect the nigrostriatal dopaminergic system from 6-hydroxydopamine

We tested the hypothesis that fibroblasts, which had been genetically engineered to produce fibroblast growth factor-2 (FGF-2), can protect nigrostriatal dopaminergic neurons. Three groups of rats received either a burr hole only (n=5) or implantation of fibroblasts, which had been genetically engineered to produce beta-galactosidase (beta-gal) (n=8) or FGF-2 (n=8), at two sites in the right striatum. Two weeks later, the animals received an injection of 25 microg of 6-hydroxydopamine hydrobromide (6-OHDA) midway between the two implant sites. The group that received FGF-2-fibroblasts had significantly fewer apomorphine-induced rotations than the groups that received a burr hole only or beta-gal-fibroblasts at weeks 2 and 3 following lesioning with 6-OHDA. Testing for amphetamine-induced rotation revealed a mild reduction in rotation in the beta-gal-fibroblast group compared to the burr hole only group, but a striking attenuation of amphetamine-induced rotation in the FGF-2-fibroblast group. There was also preservation of TH-IR neurons on the lesioned side relative to both control groups. The size of the grafts and the gliosis surrounding the injection sites did not differ between the FGF-2-fibroblast and beta-gal-fibroblast groups. To further characterize the production of FGF-2 by the FGF-2-fibroblasts, we implanted FGF-2-fibroblasts and beta-gal-fibroblast into the striatum of rats but did not lesion the animals with 6-OHDA. The animals were then sacrificed at 1, 2 and 5 weeks following implantation. Prior to implantation the FGF-2 fibroblasts contained 148 ng/mg of FGF-2-immunoreactive (FGF-2-IR) material per mg of protein of cell lysate. After implantation FGF-2-IR material was noted in the grafts of FGF-2-fibroblasts, most conspicuously at 1 and 2 weeks following implantation. We also noted FGF-2-IR material in the nuclei of reactive astrocytes adjacent to the implants, and OX-42-immunoreactive (OX-42-IR) cells adjacent and occasionally within the implants. Our work indicates that fibroblasts genetically engineered to produce FGF-2 and implanted in the striatum can protect the nigrostriatal dopaminergic system and may be useful in the treatment of Parkinson's disease.

Factors affecting gallstone recurrence after successful extracorporeal shock wave lithotripsy

Ninety-six patients treated successively for symptomatic cholelithiasis with extracorporeal shock wave lithotripsy (ESWL) and oral bile acid therapy consisting of ursodeoxycholic acid in daily dosages of 600 mg were prospectively followed for gallstone recurrence for a median of 13 months. Ultrasonography was performed to detect stone recurrence at 3, 6, and 12 months, and then yearly after the termination of therapy. Recurrent stones were found in 17 patients (18%). The cumulative probability of gallstone recurrence was 15.8% at 12 months, 26.1% at 24 months, and 30.7% at 36 months. The probability of stone recurrence over the entire period of observation was not dependent on stone number, whereas the median interval to detection of recurrence was significantly shorter in the patients with multiple stones (2 months) than in those with solitary stones (8 months) (p < 0.05). The rate of impaired gallbladder contractility was higher in patients with recurrence (8/15, 53.3%) when compared with those with no recurrence (15/72, 20.8%) (p < 0.01). Neither age, gender, or stone characteristics predicted stone recurrence. Only one patient with a recurrence reported biliary pain. Of the 15 patients with recurrent stones who opted for further nonsurgical treatment, complete stone disappearance was achieved in 10. Impaired gallbladder function may predict gallstone recurrence after ESWL.

Immunohistochemical and ultrastructural study of clinically nonfunctioning pituitary adenomas

Sixty-five clinically nonfunctioning pituitary adenomas were studied by immunohistochemistry, and 12 cases were also analyzed by electron microscopy. Thirty-nine cases (60%) were immunohistochemically identified as hormone-producing adenomas. Six adenomas produced multiple hormones. Electron microscopy found seven null cell adenomas and five oncocytomas. The oncocytomas had a significantly higher incidence of hormone expression that the null cell adenomas. These results indicate that clinically nonfunctioning pituitary adenomas produce hormones, even though blood hormone levels are normal or low. Furthermore, the evidence of multihormonal production implies that two or more cell lineages including a protein hormone-producing type and a glycoprotein hormone-producing type may exist in the same nonfunctioning pituitary adenoma.

Effects of modification of the hydrophobic C-1-C-16 segment of tautomycin on its affinity to type-1 and type-2A protein phosphatases

Among the naturally occurring toxins that are known to have specific inhibitory effects on type-1 and type-2A protein phosphatases (PP1 and PP2A), tautomycin (TM) is unique in that it exhibits significantly higher affinity to PP1 than to PP2A. The ratio of the dissociation constant for the PP1-TM interaction to that for the PP2A-TM interaction (the PP1/PP2A ratio) is 0.01-0.03. The aim of the present study was to evaluate the possible contributions of the C-1-C-16 segment of TM to the affinity characteristics of the toxin. The relatively hydrophobic segment contains a spiroketal motif whose enantiomeric form is present in okadaic acid (OA), which exhibits exceedingly higher affinity to PP2A than to PP1. We therefore synthesized two TM analogues: TM1 in which the side chains of the spiroketal motif of TM were removed but its absolute configuration was retained, and TM2 in which the spiroketal motif of TM1 was replaced with its enantiomeric form. The effects of TM, TM1 and TM2 on the activities of the native catalytic subunits of PP1 (PP1C) and PP2A and a recombinant gamma isoform of PP1 (PP1gamma) were examined. The PP1/PP2A ratio determined thereby was 0.2-0.5 for TM1 and 5-10 for TM2. Both the presence of the side chains and the stereochemistry of the spiroketal moieties may be major determining factors for the affinity characteristics of TM. We also show that a monoclonal antibody raised against OA binds to TM2 albeit with much lower affinity than to OA, whereas it exhibits no measurable affinities to TM and TM1.