pH-dependent fusion of synaptosomal membrane studied by fluorescence quenching method

We have found that both the synaptic vesicles (SV) and synaptic plasma membrane vesicles (SPM) have an activity to fuse with phosphatidylcoline/phosphatidylserine liposomes in a pH-dependent manner. The activity increases with decreases in extravesicular pH. At a pH lower than 4.0, the activity is almost steady at its maximum value, and there was a rapid drop around pH 5.5. The pH-dependent fusion was inhibited by proteolysis with trypsin; hence, at least in part, some membrane proteins play an important role in these pH-dependent fusion processes. To find specific markers, we screened various protein modifiers and found that anion channel blockers, stilbene derivatives (DIDS and SITS) and glibenclamide, affected the fusion process. DIDS and SITS decreased the fusion activity with an IC50 of 180 and 300 microM, respectively, whereas glibenclamide, on the contrary, increased it. From the results of an autoradiogram using 3H-tagged DIDS, a 30 kDa DIDS-binding protein was identified in the synaptic plasma membrane, which is possible to be responsible for the pH-dependent fusion.     

Lymphocyte subpopulations and T-cell subsets in human oral cancer tissues: immunohistologic analysis by monoclonal antibodies

A series of T-cell-specific monoclonal antibodies (Leu-1, Leu-2a, and Leu-3a) and B-cell-specific monoclonal antibody (HLB-1) were used to detect the localization and intensity of infiltration of lymphocyte subpopulations and T-cell subsets in frozen sections of 17 patients with the oral cancer. The vast majority of the lymphocyte infiltrates in the oral cancer tissues were reactive with Leu-1. In contrast, B cells were detectable with HLB-1 in only 2 of 17 cases. Leu-2a-positive cells were dominant in four cases, whereas Leu-3a positive cells were dominant in only three cases. In seven cases, both cells infiltrated to the same degree. Leu-2a positive cells tended to be dominant in the cases with earlier clinical stages.     

Development of the subclavian artery in the loggerhead turtle (Caretta caretta) studied by the injection method]

In the turtle, the left aorta and the pulmonary trunk originate from the right ventricle, while the right aorta takes its origin from the left ventricle as a functional systematic arch. The subclavian artery arises from the brachiocephalic artery on each side, and passes ventral to the vagus nerve and the jugular vein. These features are basically the same as in birds, and the subclavian artery of the adult turtle corresponds to a secondary artery from the viewpoint of comparative anatomy. Many investigators, including one of the present authors (Suzuki, 1987), have studied the development of the aortic arch and the subclavian artery in the chick embryo, but not in the turtle. The present authors examined it in Loggerhead turtle (Caretta caretta) embryos, from 14 days of incubation to completion of the aortic arch (27 days incubation). All blood vessels were injected with Berlin blue solution using a fine glass needle inserted into the aortic trunk through the ventricle of the heart. The following results were obtained. 1. In the turtle embryo the primary subclavian artery develops first, but is replaced by the secondary subclavian artery as in the chick. 2. The primary subclavian artery arises from the 12th dorsal intersegmental artery and passes dorsal to the posterior cardinal vein. In the 16-day embryo, it gives rise to capillary nets both cranially and caudally at the base of the forelimb bud along the inner surface of the thoracic wall. 3. At 19 days of incubation, a small blood vessel arises from the aortic sac at the origin of the third aortic arch and passes laterally, ventral to the anterior cardinal vein. The vessel then extends caudally, and finally, at 21 days of incubation, connects to the cranial part of the capillary net of the primary subclavian artery at about the middle of the lateral thoracic wall. After the completion of the connection, the vessel from the aortic sac is called by the name "the secondary subclavian artery." 4. The secondary subclavian artery gradually increases in size, while the proximal part of the primary one begins to atrophy and finally disappears at 27 days of incubation. After this, the forelimb bud receives its blood supply only from the newly-formed secondary subclavian artery. 5. In conclusion, in the turtle, the secondary subclavian artery is formed by connection of the primary artery with the caudally extending artery arising from the aortic sac, while in the chick it is derived from an outgrowth of the primary artery.(ABSTRACT TRUNCATED AT 400 WORDS)     

Suppressor activity in the supernatant of T cell clones derived from chimeric mouse spleen cells

The supernatant from cultures of T cell clones derived from (BALB/c----C3H/He) chimeras suppresses BALB/c anti-C3H/He or BALB/c anti-C57BL/6 MLRs. When we studied the alloantigen specificity of the suppressor activity in culture supernatant, we observed three types of the suppressor activity (i.e., the suppressor activity against BALB/c anti-C3H/He MLR, against BALB/c anti-C57BL/6 MLR, and against both MLRs) on day 3 after stimulation of the T cell clones with 20% crude IL2 and feeder cells. Since the alloantigen specificity fluctuated somewhat with time, we considered that a time-course study was needed to determine it correctly. We thought it unlikely that any IFN-gamma or PGE2 in the culture supernatant of the T cell clones would have mediated the suppression. Our results suggest that alloantigen specific and non-specific suppressor T cells exist in bone marrow chimeras. The former appears to play an important role in inducing and maintaining transplantation tolerance, while the latter seems to have a rather harmful effect upon chimeras.     

Tissue distribution of the Pk antigen as determined by a monoclonal antibody

Using an anti-Pk monoclonal antibody (mAb) designated CPK-1, the expression of the Pk antigen was assessed on normal human tissue from non-Pk individuals. Although the Pk antigen was detected on fibroblasts and blood vessels as previously reported, it was also found on smooth muscle cells of the digestive tract and the urogenital system. Pk was also found on glandular cells of the stomach, oesophagus and prostate. Additionally, CPK-1 reacted weakly with oesophagus squamous cells, and a small number of glomeruli and tubules in the kidney. The mechanism of expression of the Pk determinant in non-Pk individuals is discussed.     

Continuous administration of gonadotrophin-releasing hormone agonist during the luteal phase in IVF

BACKGROUND: It has been reported that ceasing the administration of gonadotrophin-releasing hormone (GnRH) agonist causes a profound suppression of circulating serum gonadotrophins. A comparative prospective and randomized study was conducted to investigate the effect of continuous administration of GnRH agonist during the luteal phase in an ovarian stimulation programme for IVF. METHODS: GnRH agonist was administered intranasally from the midluteal phase of the previous cycle, and pure FSH administration started on cycle day 7. In the continuous-long protocol (cL) group (n = 161 ), GnRH agonist administration was continued until 14 days after oocyte retrieval. In the long protocol (L) group (n = 158 ), GnRH agonist was administered until the day before human chorionic gonadotrophin (HCG) administration. RESULTS: The implantation rate and live birth rate per unit of transferred embryos were significantly higher in the cL group than the L group (P < 0.05 ). Serum LH and FSH concentrations on the day of, and 1 day after, HCG administration were significantly lower in the L group than the cL group (P < 0.01 ). CONCLUSIONS: Continuation of GnRH agonist administration during the luteal phase might facilitate implantation, and prevent the profound suppression of serum gonadotrophins.     

Further insight into the task-dependent excitability of motor evoked potentials in first dorsal interosseous muscle in humans

We have reexamined the contradictory evidence in which task-dependent excitation of motor evoked potentials (MEPs) in the first dorsal interosseous (FDI) muscle was stronger with increasingly more complex finger tasks than with individual finger movement tasks. In the first step of the experiment, based on previous findings, we investigated remarkable functional differences between intrinsic and extrinsic hand muscles during complex finger tasks (precision and power grip). During the performance of the tasks, the optimal stimulus intensity of the transcranial magnetic stimulation (TMS) was applied to the contralateral motor cortex. MEPs of the FDI, extensor carpi radialis (ECR), and flexor carpi radialis (FCR) muscles were recorded simultaneously with increased background EMG activity step by step in both tasks. The intensity threshold of TMS was lower in the precision grip. Furthermore, the MEP amplitudes of FDI muscle dependent on the background EMG activity were different between these two tasks, i.e., MEP amplitudes and regression coefficients in a precision grip were larger than those in a power grip. Although our results for MEP amplitude and threshold in the FDI muscle were similar to previous reported evidence, the different contributions of a synergistic muscle (in particular, the ECR muscle) during performance in these tasks was new evidence. Since there were no differences in cutaneous afferent effects on both tasks, corticomotoneuronal (CM) cells connected to FDI motoneurons seemed generally to be more active during precision than power gripping, and there were different contributions from synergistic muscles during the performance of these tasks. In the second part of the experiment, the results obtained from the complex tasks were compared with those from a simple task (isolated index finger flexion). MEP amplitudes, dependent on the background EMG activity during isolated index finger flexion, varied among subjects, i.e., the relationship between the MEP amplitude and the background EMG of the FDI muscle showed individual, strategy-dependent modulation. There were several kinds of individual motor strategies for performing the isolated finger movement. The present results may explain the previous contradictory evidence related to the contribution of the CM system during coordinated finger movement.     

FT-2 antigen for distinguishing lymphocyte subpopulations in the developing thymus

The surface phenotypes of lymphoid cells in the developing embryonic thymus were characterized by using monoclonal antibodies. FT-2 antigen thus defined was predominantly expressed on thymocytes in the earlier embryonic stages in all the inbred mouse strains tested. The immunofluorescence and immunoperoxidase tests indicated that, like FT-1 antigen, the proportion of FT-2+ fetal thymocytes rapidly decreased with increase in gestation time, and these cells disappeared by day 19 of gestation. The treatment of fetal thymocytes with anti-FT-1 plus complement eliminated not only FT-1+, but also FT-2+ cells, whereas the treatment with anti-FT-2 failed to eliminate approximately 40% of FT-1+ cells, suggesting that embryonic thymocytes can be provisionally divided into at least three subpopulations, FT-1+2+, FT-1+2- and FT-1-2-.     

Detection of culprit lesion in patients with unstable angina pectoris by using ATP thallium-201 myocardial SPECT

The purpose of this study is to determine the diagnostic accuracy for detection of culprit lesions in patients with unstable angina. Both ATP 201Tl SPECT and coronary angiography were performed in 51 patients with unstable angina pectoris within a week since the last attack. SPECT images were divided into 17 segments and the regional uptakes were scored semiquantitatively (0 = normal to 3 = no activity) and compared with the coronary angiographic findings. ATP 201Tl SPECT revealed decreased uptakes in 54 of 56 culprit lesions. The sensitivity, specificity and accuracy for detection of culprit lesions were 96.4%, 89.5% and 92.4%, respectively. Although adverse effects during ATP administration were complicated in 28 (54.9%) patients, all the complications were mild and resolved within two minutes. ATP 201Tl SPECT is sensitive and reliable method for detecting culprit lesions and can be performed safely even at acute phase in patients with unstable angina pectoris.     

Prevalence and symptomatology of comorbid obsessive-compulsive disorder among bulimic patients

This study sought to assess the prevalence and symptomatology of comorbid obsessive-compulsive disorder (OCD) among Japanese subjects who met the DSM-III-R criteria for bulimia nervosa (BN). The Structured Clinical Interview for DSM-III-R Patient Version was used to distinguish 26 BN patients with concurrent OCD from 52 BN patients without OCD. Obsessive-compulsive symptoms in BN subjects with concurrent OCD were evaluated using the Japanese version of the Yale-Brown Obsessive-Compulsive Scale. There were no differences in the prevalence of concurrent OCD between BN subjects with and without a lifetime history of anorexia nervosa. Among BN subjects with concurrent OCD, symptoms related to symmetry and order were most frequently identified, followed by contamination and aggressive obsessions, and checking and cleaning/washing compulsions. Bulimia nervosa subjects with concurrent OCD were more likely than subjects without OCD to have more severe mood and core eating disorder psychopathology. Comorbid OCD is a common phenomenon in Japanese bulimics (33%) similar to that suggested in BN subjects in the Western countries. Obsessive-compulsive symptoms related to symmetry and order were most frequently observed in BN subjects with concurrent OCD, which was a similar finding to that reported among restricting anorexic subjects.