Functional analysis of simian immunodeficiency virus SIVAGM long terminal repeat

We have previously shown that long terminal repeats (LTRs) derived from various isolates of SIV_AGM share a unique functional property. In the absence of viral Tat, all SIV_AGM LTRs act as much more efficient promoters than any of the other LTRs derived from representative primate immunodeficiency viruses. In the presence of Tat, however, SIV_AGM LTRs are activated relatively inefficiently. To map the elements that confer these features on the SIV_AGM LTR, a number of deletion mutants were constructed, and their promoter activities were determined using a bacterial CAT gene as a marker. The results obtained indicated that various elements located in the U3 region may contribute to the high basal promoter activity and that no negative elements are present in the region. The Tat-responsive sequence TAR was localized to the R region as observed for the other LTRs. A mutant carrying a single nucleotide deletion in this region completely lost responsiveness to Tat protein.     

Dilute solution properties of imogolite

Imogolite, a natural product in the clay fraction of Japanese soil, was characterized through its dilute solution properties. Various methods were employed for this characterization, including viscosity, sedimentation, static/dynamic light scattering, and small angle X-ray scattering. All these measurements have revealed consistently that imogolite is represented by a rigid thin rod within the accuracy of available theories, where its repeat unit is composed of twelve gibbsite units. Since the evaluation of the chain length from the observed quantities depends on the molecular weight distribution, its effect was also considered where M_w/M_n ≈ 1,2 was estimated from the sedimentation profile.     

Peritoneal macrophages which phagocytose autologous polymorphonuclear leucocytes in guinea-pigs. I: induction by irritants and microorgansisms and inhibition by colchicine.

In order to examine macrophages phagocytosing polymorphonuclear leucocytes (PMNs) in detail, we established a new method, whereby a large number of PMN-phagocytosing macrophages (PPMs) were easily induced. PPMs were harvested from the peritoneal cavity after thioglycollate medium, oyster glycogen, phytohaemagglutinin (PHA), L. monocytogenes or S. aureus had been injected i.p. into guinea-pigs. When thioglycollate medium or oyster glycogen was injected i.p., the number of the PPM reached a peak 48 h later and PPM formed 20% or more of total macrophages. When L. monocytogenes or S. aureus was injected i.p., the ratio of PPM to total macrophages reached a peak 24 h later. Morphologically, some of the phagocytosed PMNs were not degenerated and the others were at various stages of degeneration. The ability of macrophages to phagocytose PMNs was suppressed when 10(-6) mol/kg of colchicine was administered i.p. 1 day after the injection of the irritants.     

Gastric motility in patients with recurrent gastric ulcers.

The existence of abnormal gastric motility in gastric ulcer disease remains controversial. The aim of this study was to characterize gastric motility in patients with recurrent gastric ulcers. Studies were performed in 10 control subjects and in 24 patients with recurrent active gastric ulcer disease as diagnosed by gastrointestinal endoscopy. Gastric motility was evaluated by cutaneous electrogastrography (EGG) and by gastric semi-liquid meal emptying. The EGG was recorded before and after ingestion of a test meal containing 20 mg/kg of acetaminophen. Patients with a dominant EGG frequency of greater than 0.06 Hz were defined as tachygastria, while those with a frequency of less than 0.04 Hz were defined as bradygastria. A transient frequency decrease, called postprandial dip (PD), was identified visually. The degree of gastric emptying was determined from the serum acetaminophen concentration 45 minutes after the meal. Control subjects showed no irregularity in their dominant EGG frequency in tither fasting or postprandial states. PD was observed in 8 control subjects. In patients presenting with active gastric ulcers, abnormal patterns in the dominant EGG frequency (either as tachygastria or bradygastria) were observed in 14 of the 24 patients when fasting and in 15 of them in the postprandial state. After successful treatment, the number of patients with abnormal patterns in their dominant EGG frequency remained unchanged, while PD was observed in 11 patients. No significant difference was observed in the EGG power ratio as a result of successful treatment. Gastric emptying was significantly delayed compared with controls in both the active and healed stages. These findings suggest that abnormal gastric motility, including gastric electrical abnormalities and delayed gastric emptying, plays an important role in the pathophysiology of recurrent gastric ulcers.     

Lyotropic mesophase of imogolite, 1. Effect of polydispersity on phase diagram

The acidic aqueous solution of imogolite is proposed to be an ideal lyotropic system. No temperature dependence was marked on the two phase boundary concentrations (A and B points) of imogolite solutions as predicted by the theories of Flory and Onsager. A satisfactory quantitative agreement was observed with Onsager's theory. The polydispersity of rod lengths was found to shift the A point towards lower concentrations than expected from theory.     

Two familial cases of Jordans' anomaly. Ultrastructural studies and the development of fat-containing vacuoles in the neutrophilic series

A study was conducted on two brothers with Jordans' anomaly. Fat-containing vacuoles were noticed in all leukocytes of the peripheral blood and cells of the myeloid series including myeloblasts, but the serum lipids showed no abnormalities. However, cells of the erythroid series, megakaryocytes and platelets did not contain these vacuoles. An increase in vacuole number was observed as the leukocytes matured. Histochemically, it was suggested that these vacuoles contained neutral fat based on staining with Sudan III and Nile blue sulfate. Ultrastructurally, these vacuoles were unassociated with lysosomes or other cell organelles. Although the etiology of Jordans' anomaly could not be clarified by this study, genetic factors may be involved.     

Endogenous peroxidase activity in primary culture of human thyroid cells. Localization and measurement

Intracellular localization of and an assay method for endogenous peroxidase (PO) activity were studied using primary culture of thyroid cells obtained from patients with hyperthyroidism. PO activity was visualized by cytochemical reaction and was located mainly in perinuclear cisternae and rough endoplasmic reticulum. With increased culture time, the number of cells showing positive PO activity and amount of the enzyme reaction product in individual cells showed a parallel decrease. For measurement of PO activity, cultured thyroid cells were frozen and thawed and then incubated with citric acid buffer solution containing o-phenylenediamine (opd) and hydrogen peroxide. After incubation, the optical density (OD) of the solution colorized by endogenous peroxidase was measured at 405 nm using a microplate reader. About 1 X 10(4) cells were sufficient for assay of PO activity. Using the above method to assay PO activity and sandwich enzyme immunoassay for thyroglobulin (TG), chronological changes in the PO activity and TG concentration in the culture medium were examined. Although the cells showed no decrease in number, PO activity and TG concentration decreased chronologically. When the ratio of PO activity to TG concentration was calculated, in 3 cases the ratio was almost constant, and in the remaining two, it decreased chronologically. The present biochemical method thus seems useful for determining peroxidase activity of cultured thyroid en masse.     

Convergence of hepatoportal glucose-sensitive afferent signals to glucose-sensitive units within the nucleus of the solitary tract

Units which are activated by ascending impulses from the liver within the nucleus of the solitary tract (NTS) were identified by electrical stimulation delivered to the hepatic branch of the vagus. Responses of descending units were eliminated by a collision test. The units which showed decreased firing rates during portal infusion of isotonic glucose solution were also glucose-sensitive so that they showed decreased firing rates during topical application of glucose by means of micro-electro-osmotic techniques. It is concluded that glucose-sensitive neurons exist within the NTS and also that they are functionally linked with hepatoportal glucose-sensitive afferent units.