Inhibition of cellular growth and induction of apoptosis in pituitary adenoma cell lines by the protein kinase C inhibitor hypericin: potential therapeutic application.

Protein kinase C (PKC) is an enzyme involved in the regulation of cellular growth, proliferation, and differentiation in a number of tissues including the anterior pituitary, in which it is also believed to play a role in hormone secretion. Protein kinase C activity and expression have been found to be greater in adenomatous pituitary cells than in normal human and rat pituitary cells and higher in invasive pituitary tumor cells than in noninvasive ones. Inhibition of PKC activity has been shown in a variety of tumor cells to inhibit growth in a dose-related fashion. The purpose of the current study was to determine whether hypericin, a potent inhibitor of PKC activity that may be administered clinically, alters the growth and proliferation in established pituitary adenoma lines and to determine if inhibition of PKC activity induces apoptosis, as reported in some other tumor cell types. Two established pituitary adenoma cell lines, AtT-20 and GH4C1, were treated with hypericin in tissue culture for defined periods following passage. Inhibition of growth was found to be dose dependent in all three cell lines in low micromolar concentrations of hypericin, as determined by viable cell counts, methylthiotetrazole assay, and [3H]thymidine uptake studies. Concentrations of hypericin as low as 100 nM also induced apoptosis in these established lines, whereas treatment of normal human fibroblasts with a concentration of 10 microM failed to induce apoptosis. The potential use of hypericin in the therapy of pituitary adenomas warrants additional in vitro investigations with the aim of later moving toward therapeutic trials in selected patients in whom surgical or medical therapy has failed.

Respiratory muscle activity during sleep-induced periodic breathing in the elderly.

During spontaneous sleep-induced periodic breathing in elderly subjects, we have found that tidal volume oscillations are related to reciprocal oscillations in upper airway resistance. The purpose of this study was to address the mechanism of the relationship between oscillations in tidal volume and upper airway resistance in elderly subjects with sleep-induced periodic breathing. We hypothesized that the spontaneous periodic breathing observed in non-rapid-eye-movement (NREM) sleep in elderly subjects would be closely related to fluctuations in upper airway resistance and not to changes in central motor drive to ventilatory pump muscles. Therefore, in eight healthy elderly subjects, we measured costal margin chest wall peak moving time average electrical inspiratory activity (CW EMG), ventilation variables, and upper airway resistance during sleep. Five of eight subjects had significant sine wave oscillations in upper airway resistance and tidal volume. For these five subjects, there was a reciprocal exponential relationship between peak upper airway inspiratory resistance and tidal volume or minute ventilation [r = -0.60 +/- 0.20 (SD) (P < 0.05) and -0.55 +/- 0.26 (P < 0.05), respectively], such that as resistance increased, ventilation decreased. The relationship between CW EMG and tidal volume or minute ventilation was quite low (r = 0.12 +/- 0.32 and -0.07 +/- 0.27, respectively). This study demonstrated that oscillations in ventilation during NREM sleep in elderly subjects were significantly related to fluctuations in upper airway resistance but were not related to changes in chest wall muscle electrical activity. Therefore, changes in upper airway caliber likely contribute to oscillations in ventilation seen during sleep-induced periodic breathing in the elderly.

Longitudinal study of the association between ABO phenotype and total serum cholesterol level in a Japanese cohort.

The relationship between ABO blood phenotype and total serum cholesterol (TC) level was examined in a Japanese population to determine whether an elevated TC level is associated with phenotype A, as has been demonstrated in many West European populations. Such studies in nonwhite populations are scarce, and findings generally failed to demonstrate the relationship. Inconsistent results from cross-sectional studies of various racial groups with widely varying ages raised an age effect as a possible explanatory factor. It was also suggested that the ABO-TC association may not be apparent in populations with low fat intake or low mean cholesterol level. These hypotheses are addressed by examining long-term TC data collected serially from the unexposed controls of the atomic bomb survivors in Hiroshima and Nagasaki who were participants of the Adult Health Study program at the Atomic Bomb Casualty Commission-Radiation Effects Research Foundation between 1958 and 1986. The statistical method of growth curve analysis, through the mixed effect model of Laird and Ware [1982], was used to model age-dependent changes in cholesterol levels within individuals. The effects of the ABO polymorphism in modifying the resultant growth curve are examined. We demonstrate that TC levels are elevated on average by about 4 mg/dl in phenotype A compared to non-A in the Japanese (P < 0.00001), and that this relationship is maintained from early to late adulthood, independent of sex, body mass index, cohort status, or city of residence. Thus, phenotype A individuals may be more predisposed to cardiovascular disease through one of its major risk factors. This is the first study of the ABO-cholesterol association in the Japanese, and the first based on a cohort with longitudinally collected TC data.

Imbalance of blood group A subtypes and the existence of superactive B gene in Japanese in Hiroshima and Nagasaki.

Blood type A can be classified into subgroups A1, A2, and A1-A2 intermediate on the basis of serological criteria. An excess of A2B over A2, noted in some black populations and among the Japanese, though not in caucasoids, is inconsistent with the classical Mendelian mode of inheritance of the allelic A1 and A2 genes. Characterization of the enzymatic properties of the blood group A and B enzymes in the serum has shown that serological A2B blood of some blacks contains A1 enzyme and a superactive B* enzyme. An excess of A2B found in a study of over 15,000 residents of Hiroshima and Nagasaki prompted investigation of the characteristics of the A and B enzymes in 60 blood samples, 37 from individuals in 13 unrelated families and 23 from other unrelated individuals in the two cities. Among 27 unrelated individuals whose blood types were unequivocally classified serologically as A2B, 15 were confirmed as A2B enzymatically; eight contained A1 and B* enzymes, not A2 or B enzymes, thus being A1B*; two contained Aint and B* enzymes, thus being AintB; and results for the remaining two were ambiguous. Hiroshima differs from Nagasaki in the frequency of the A2B serological type and also in the occurrence of the B* enzyme, Nagasaki having a higher proportion of both. If one considers those cases in which family study was possible, the transmission of the B* enzyme appears to be compatible with the Mendelian mode of inheritance.(ABSTRACT TRUNCATED AT 250 WORDS)

Characteristics of the upper airway pressure-flow relationship during sleep.

In examining the mechanical properties of the respiratory system during sleep in healthy humans, we observed that the inspiratory pressure-flow relationship of the upper airway was often flow limited and too curvilinear to be predicted by the Rohrer equation. The purposes of this study were 1) to describe a mathematical model that would better define the inspiratory pressure-flow relationship of the upper airway during sleep and 2) to identify the segment of airway responsible for the sleep-related flow limitation. We measured nasal and total supralaryngeal pressure and flow during wakefulness and stage 2 sleep in five healthy male subjects lying supine. A right rectangular hyperbolic equation, V = (alpha P)/(beta + P), where V is flow, P is pressure, alpha is an asymptote for peak flow, and beta is pressure at a flow of alpha/2, was used in its linear form, P/V = (beta/alpha) + (P/alpha). The goodness of fit of the new equation was compared with that for the linearized Rohrer equation P/V = K1 + K2V. During wakefulness the fit of the hyperbolic equation to the actual pressure-flow data was equivalent to or significantly better than that for the Rohrer equation. During sleep the fit of the hyperbolic equation was superior to that for the Rohrer equation. For the whole supralaryngeal airway during sleep, the correlation coefficient for the hyperbolic equation was 0.90 +/- 0.50, and for the Rohrer equation it was 0.49 +/- 0.25. The flow-limiting segment was located within the pharyngeal airway, not in the nose.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of RA233 on metastasis in dogs with osteosarcomas.

The influence of RA233, an inhibitor of platelet function, on the occurrence of metastasis in 18 dogs with osteosarcomas was evaluated. At least 24 hours before surgical removal of the primary tumor, dogs were given RA233 orally (20 mg/kg of body weight divided into 3 equal doses). Original sites of the osteosarcoma included humerus, 6 dogs; radius, 5 dogs; tibia, 3 dogs; femur, 2 dogs; maxilla, 1 dog; and mandible, 1 dog. Survival time for 13 dogs euthanatized for progression of neoplastic disease ranged from 3 months to 10 months, with a mean survival time of 5.5 months. Medication was discontinued in 1 dog because of possible adverse reaction. One dog died of disease unrelated to the tumor, and one dog was euthanatized after the surgery. Two dogs were tumor free 9 and 17 months after surgery. Seemingly, the metastasis potential was not diminished in dogs given 20 mg of RA233/kg/day.

Serum TSH, thyroglobulin, and thyroidal disorders in atomic bomb survivors exposed in youth: 30-year follow-up study.

Follow-up examinations to determine the frequency of thyroidal disorders were conducted by the Radiation Effects Research Foundation (RERF) on individuals in Hiroshima and Nagasaki who were less than 20 yr of age at the time of exposure to the atomic bomb. Concentrations of serum thyroid stimulating hormone (TSH), thyroglobulin (TG), and anti-TG antibody 30 yr after exposure were also determined. Nontoxic uninodular goiter was found in 13 cases of the 100 + rad exposed group (n = 477) and in three cases of the nonexposed group (n = 501). The prevalence in the 100+ rad exposed group was significantly higher (chi-squared = 6.584, p less than 0.01). Thyroid cancer was found in eight exposed cases, all of whom were in the 100+ rad group, and the prevalence was significantly greater (chi-squared = 7.919, p less than 0.01). Regardless of the presence or absence of thyroid disorders, serum TSH and TG levels were not statistically different between the 100 rad + exposed and nonexposed groups. Although hypothyroidism was found in 23 of the total cases, there was no correlation between its development and exposure to ionizing irradiation.

Effects of atomic bomb radiation on the differentiation of B lymphocytes and on the function of concanavalin A-induced suppressor T lymphocytes.

The differentiation of peripheral blood B lymphocytes into immunoglobulin-producing cells (Ig-PC) by pokeweed mitogen (PWM) and the function of concanavalin A (Con A)-induced suppressor T lymphocytes were examined to elucidate the late effects of atomic bomb radiation. A total of 140 individuals, 70 with an exposure dose of 100 rad or more and an equal number with an exposure dose of 0 rad matched by sex and age, were selected from the Nagasaki Adult Health Study (AHS) sample. Both the differentiation of peripheral blood B lymphocytes into Ig-PC by PWM and the function of Con A-induced suppressor T lymphocytes tended to be more depressed in the exposed group than in the control group, but a statistically significant difference could not be observed between the two groups. The function of Con A-induced suppressor T lymphocytes tended to decrease with age, but a statistical significance was detected only for percentage suppression against IgM-PC.

The frequency among Japanese of heterozygotes for deficiency variants of 11 enzymes.

Eleven human enzymes, chosen for this study because of relatively small coefficients of variation for mean activity, have been surveyed for the frequency with which activities less than or equal to 66% of the mean value occur. This criterion should detect almost all heterozygotes for variants lacking any activity plus a fraction of the persons with variants characterized by markedly depressed activity and/or instability. The enzymes surveyed are TPI, PGK, AK1, LDH, GAPD, GPI, PK, 6PGD, G6PD, GOT1, and HK. The number of determinations per enzyme ranged from 310 to 3,173, for a total of 26,634 determinations. Family studies have thus far been possible in 52 instances in which the initial observation of activity less than or equal to 66% of normal was confirmed. In every instance, a parent exhibited a similar finding, giving confidence that a true genetic entity was being detected. With this approach, the frequency of heterozygotes per 1,000 determinations varied from 0.0 (AK1, 6PGD) to 13.8 (PK), with an average of 2.4. For these same systems, in this laboratory the frequency of "rare" electrophoretic variants is 2.3/1,000, the ratio of the latter to the former thus being 1.0 in Japanese. Our experience with these deficiency phenotypes to date suggests that for selected enzymes such phenotypes can be incorporated into a program designed to detect mutational events.

The relationship of hepatitis B surface antigen and antibody to atomic bomb radiation in the Adult Health Study sample, 1975-1977.

A frequency of positive hepatitis B surface antigen (HBsAg) and antibody (anti-HBs) was determined among 2566 atomic bomb survivors in Hiroshima and Nagasaki, Japan during the two-year period 1975 to 1977. The frequency of positive HBsAg (79% of subjects remained persistently antigen positive) was significantly higher in those exposed to 100 rad or more than in the controls. This difference between exposure groups was more marked among the younger age groups. However, contrary to expectation, there was no difference between the dose groups in the distribution by high vs. low titers among the antigen-positive individuals. There was no difference between the two comparison groups in the occurrence of positive anti-HBs reactions (prevalence of hepatitis B virus). The above findings suggest that immune competence, using the prevalence of positive HBsAg as an index, is depressed in the high dose group, but further study, including follow-up of those with persistent positive HBsAg reactions, is called for. With respect to HBsAg subtypes, adr occurs with higher and adw with lower frequency in Nagasaki than in Hiroshima, corresponding to earlier reports for the Japan archipelago of reverse and complementary distributions of these two subtypes.

Peripheral lymphocyte response to PHA and T cell population among atomic bomb survivors.

The percentage of T lymphocytes of atomic bomb survivors showed no change as a function of age or exposure dose. The percentage of T cells was slightly lower in malignant-tumor patients than in the control group, but was significantly higher in the group with chromosomal aberrations than in the control group. The percentages of phytohemagglutinin (PHA)-induced transformation of peripheral lymphocytes decreased significantly with age in the 0 rad control group and the 200+ rad exposure group, particularly so in the latter. The malignant-tumor group also showed lower percentages of PHA-induced transformation than the control group. The percentages of PHA-induced transformation of lymphocytes of the chromosomal-aberration group were significantly depressed as compared with that of the control group.

Search for mutations affecting protein structure in children of atomic bomb survivors: preliminary report.

A total of 289,868 locus tests, based on 28 different protein phenotypes and using one-dimensional electrophoresis to detect variant proteins, has yielded one probable mutation in the offspring of "proximally exposed" parents, who received an estimated average gonadal exposure of 31 to 39 rem in the atomic bombings of Hiroshima and Nagasaki. There were no mutations in 208,196 locus tests involving children of "distally exposed" parents, who had essentially no radiation exposure.