Platelet unresponsiveness to collagen: involvement of glycoprotein Ia-IIa (alpha 2 beta 1 integrin) deficiency associated with a myeloproliferative disorder

We studied a 66-year-old man with a myeloproliferative disorder who presented with a prolonged bleeding time and marked thrombocytosis (platelet count, 3,890 x 10(9)/l). There was no past history of a bleeding disorder. The patient had normal coagulation data. His platelets completely lacked collagen-induced platelet aggregation and adhesion, but showed normal responses to other agonists. All family members tested showed normal platelet aggregation with collagen. Analysis of 125I surface-labeled platelets by two-dimensional SDS gel electrophoresis disclosed absence of the spot corresponding to platelet membrane GPIa (alpha 2) but no other significant deficiencies of major platelet glycoproteins i.e., GPIb, IIb-IIIa, and IV. Immunoisolation studies of the patient's platelets indicated that neither anti-GPIa nor anti-GPIIa (beta 1) monoclonal antibody (mAb) isolated any surface membrane proteins corresponding to GPIa. GPVI, a putative collagen receptor, was immunoisolated from the platelets. Indirect immunofluorescence study using flow cytometry confirmed that the patient's platelets were totally deficient in surface expression of the GPIa-IIa complex (alpha 2 beta 1 integrin). In contrast, phytohemoagglutinin-activated T-lymphocytes from the patient expressed normal concentrations of this complex. The data suggest that our patient had an acquired deficiency of the platelet GPIa-IIa complex, due to a myeloproliferative disorder, which might account for the absence of responsiveness of his platelet to collagen.

Environment modifies the expression of behavioral sensitization produced by methamphetamine: behavioral and neurochemical studies

Effects of environmental modulation of methamphetamine (MA)-induced behavior on the establishment and mode of expression of behavioral sensitization were examined. Rats received daily injection of MA for 10 days (1mg/kg, s.c.). Half of them were immediately returned to the home cage (home cage group) and the other half were individually confined in a cylinder with a diameter of 13cm placed inside the home cage for 3h after each injection (small cage group). Gross observations revealed that rats which received MA in the small cage did not locomote but showed sniffing and rearing. The third group received saline in the home cage (saline control group). After a 7-8 day or 17-18 day withdrawal period, all groups were injected with MA (1mg/kg or 0.5mg/kg) in their home cages. The home cage group showed significant enhancement in horizontal motor activity compared to the saline control group, indicating the establishment of locomotor sensitization. In contrast, the small cage group showed no or slight enhancement in the motor activity. However, they showed significantly more stereotyped behavior compared to both the saline control and the home cage groups. Microdialysis studies revealed no enhancement in the ability of MA to increase dopamine release from the nucleus accumbens in either the home or the small cage group compared to the saline control group, when examined after either a 7-8 day or a 17-18 day withdrawal period. These results suggest that environmental modulation of actual movement under the stimulant effect modifies the pattern and character of the stimulant-induced behavior in sensitized animals. The neurochemical basis of the establishment of behavioral sensitization and the environmental modification of its expression remain unknown.

Computer-assisted geometric design of cerebral aneurysms for surgical simulation

This report presents conceptual aspects and the clinical implications of a computer-assisted geometric design of a cerebral aneurysm and surrounding structures. The technique is based on the approximation power of the parametric spline function, which achieves interpolation and surface fitting of the arterial information obtained by conventional angiography. Computer graphic transformations including shifting, scaling, rotation, and putting different colors in different intensities make it possible to obtain the surgical simulation of a cerebral aneurysm. To our knowledge, this is the first report in which the computer graphic simulation of the surgical view of a cerebral aneurysm is made with a personal computer. Using our method, it may be possible to obtain the surgical simulation of a more complicated view by introducing a navigation system of a new style for conventional open neurosurgery. Concepts and the technical details of the method are described.

Scopolamine prevents the development of sensitization to methamphetamine

The cholinergic neurotransmission has been implicated in various forms of neural plasticity such as kindling and learning. The present study examined the effects of scopolamine, a muscarinic cholinergic antagonist, on the development of behavioral sensitization to methamphetamine (MA). Rats treated with MA (1 mg/kg, sc) for 10 days indicated significantly enhanced motor activity when tested with MA (0.5 mg/kg) after a 7-8 day withdrawal, indicating the development of behavioral sensitization. Pretreatment with scopolamine (3 mg/kg) prior to MA administration prevented the development of the phenomenon. Rats treated with scopolamine alone showed no difference in the motor activity compared to those treated with saline. These results suggest that stimulation of muscarinic cholinergic receptors plays a role in the development of behavioral sensitization.

Characterization of [3H]clozapine binding sites in rat brain

We examined the characteristics of [3H]clozapine binding sites in four rat brain regions (frontal cortex, limbic area, hippocampus and striatum) in order to elucidate the pharmacological profile of this unique atypical antipsychotic drug. The specific [3H]clozapine binding was found to be saturable and reversible in all these brain regions. Scatchard analysis of the saturation data indicated that the specific binding consisted of high- and low-affinity components. Displacement experiments showed that the muscarinic cholinergic receptor represented about 50% of [3H]clozapine binding in each brain area. Serotonin 5-HT2 and dopamine D4 receptor binding sites could also be detected by displacement experiments using ketanserin and nemonapride, respectively, in frontal cortex and limbic area, but not in hippocampus or striatum. Alpha-1, alpha-2, histamine H1, dopamine D1, D2, or D3 receptor components could not be determined within the high-affinity [3H]clozapine binding sites in any brain region. It is possible that the atypical property of clozapine may depend on the modulatory effect on dopaminergic function via 5-HT2 receptor blockade and/or may be mediated via D4 receptor blockade in the mesocortical and mesolimbic area.

Long-term treatment with haloperidol or clozapine does not affect dopamine D4 receptors in rat frontal cortex

We examined the effects of long-term treatment with haloperidol and clozapine on dopamine D4 receptors in rat frontal cortex. Dopamine D4 receptor binding sites were indirectly determined from the displacement experiments of [3H]clozapine binding using nemonapride. Three-weeks administration of haloperidol (0.5 mg/kg) or clozapine (10 mg/kg) did not significantly affect the D4 receptors in the frontal cortex. The density of D2 receptors, determined by [3H]spiperone binding to striatum, was increased by long-term treatment with haloperidol, but it was not significantly changed by that with clozapine.

Role of endothelium in the human uterine arteries during normal menstrual cycle

1. The present experiments were designed to investigate the role of endothelium in the human uterine arteries during the normal menstrual cycle. 2. Acetylcholine (ACh) produced a concentration-dependent relaxation response during the higher level of plasma 17 beta-oestradiol (E2) (follicular and luteal phases, E2 = 131.9 +/- 15.9 pg ml-1, n = 13; group I). However, the agent did not produce a definite relaxation, but produced a slight contraction during the ovulatory and menstruation phases (E2 = 19.8 +/- 2.9 pg mg-1, n = 5; group II). During the follicular and luteal phases (E2 = 181.1 +/- 9.0 pg ml-1, n = 6), ACh produced a slight contraction, but not relaxation in 6 cases (group III). Relaxation in response to A23187 in group II was not different from that in group I, while it was significantly (P < 0.05 and P < 0.005) reduced in group III. Sodium nitroprusside (SNP)-induced relaxation was similar in the three groups. 3. Correlation between the maximum response to ACh and the plasma E2 was highly significant (gamma = 0.8142, P < 0.001) in 18 cases of groups I and II, but not in all 24 cases including group III (gamma = 0.1183, NS). 4. Relaxations in response to ACh in group I or A23187 in all groups were abolished after removal of the endothelium. In group I, ACh- and A23187-induced relaxations were greatly inhibited by methylene blue or NG-nitro-L-arginine (L-NOARG) and partially inhibited by indomethacin. None of these treatments except for methylene blue modified the SNP-induced relaxation, which was significantly inhibited by methylene blue.5. The A23187-induced relaxation was hardly affected by methylene blue or L-NOARG in group III,but was partially inhibited by these agents in group II. The effect of indomethacin in inhibiting the A23187 induced-relaxation was most potent (58.9%) in group III and least (16.9%) in group I.6. There were no histological changes in 14 cases out of 18 (groups I and II), but very slight intimal thickening was observed in 4 cases in group I. On the other hand, severe intimal thickening was observed in all 6 cases in group III.7. These results indicate that, in human uterine artery strips, ACh and A23187 cause endothelium dependent relaxations, which are mediated mainly through EDRF/NO in group I, mainly prostacyclin(PGI2) in group III, or both in group II. It is suggested that lack of the production/release of EDRF/NO and/or of interaction between EDRF/NO and PGI2 might play a role in the formation of intimal thickening in human uterine arteries.

Purification, and properties of a base non-specific acid ribonuclease from bullfrog (Rana catesbeiana)

An acid ribonuclease (RNase RCL2) was purified to homogeneity on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) from a homogenate of bullfrog liver (Rana catesbeiana). The apparent molecular weight estimated from SDS-PAGE was ca. 25kDa. The pH optimum of the RNase was 5.0. The RNase released mononucleotides from RNA in the order of 3'-UMP, 3'-GMP and 3'-AMP. The N-terminal amino acid sequence of RNase RCL2 was determined up to the 20th residue, and it was found to have a 5 residue sequence homology with that of oyster acid RNase [H. Watanabe et al. J. Biochem. (Tokyo), 114, 800 (1993)]. Thus, RNase RCL2 seems to be a member of the RNase T2 family RNases. This is the first evidence of the RNase T2 family RNase in amphibians.

Fluidity of glycerol skeletal region in phospholipid bilayers: a time-resolved fluorescence depolarization study

The fluidity of glycerol skeletal region in phospholipid bilayer was investigated by the time-resolved fluorescence depolarization technique with L-alpha-dihexadecanoyl-sn-glycero-3-phospho-[N-(4-nitrobenzo-2-oxa-1,3- diazole)]ethanolamine (NBD-PE) as a fluorescent probe. In this probe, the fluorescent moiety, 4-nitrobenz-2-oxa-1,3-diazole (NBD), is attached to a nitrogen atom at the polar head group of phosphatidylethanolamine molecule. When this probe is embedded in a lipid bilayer, the NBD moiety locates near the glycerol skeletal region. The time courses of fluorescence anisotropy of NBD-PE in dipalmitoylphosphatidylcholine (DPPC) and dimyristoylphosphatidylcholine (DMPC) bilayers were analyzed using a wobbling-in-cone model, in which the molecular motion is characterized by a half cone angle (theta c) and a wobbling diffusion rate (Dw). Values of Dw of NBD moiety in phospholipid bilayers were found to be on the order of 10(7) s-1 at the physiological temperatures, which is almost the same value as that of the hydrocarbon chain in lipid bilayers. This fact indicates that the fluidity in the glycerol skeletal region is similar to that in the hydrocarbon layer.

Dysphagia caused by an anterior cervical osteophyte: case report

Cervical spondylosis and ankylosing hyperostosis of the cervical vertebrae are commonly asymptomatic. Dysphagia caused by cervical osteophyte formation is rare. We report a case of spondylotic dysphagia with striking radiographic findings. A massive anterior cervical hyperostosis was resected via the anterior cervical approach with excellent relief of dysphagia.

Effects of Ca2+ and Mg2+ on dynamics of the polar head group of phosphatidylserine bilayers

The effects of Ca2+ and Mg2+ on the molecular motion of the polar head group in phosphatidylserine (PS) bilayers were measured by the time-resolved fluorescence depolarization method probed by 1,2-dihexadecanoyl-sn-glycero-3-phospho-[N-(4-nitrobenzo- 2-oxa-1,3-diazole)]ethanolamine [formula: see text] (NBD-PE). By this method, the rate and width of the molecular motion at the fluorescent moieties in the probe molecules could be evaluated as the wobbling diffusion rate (Dw, s-1) and the half cone angle of the wobbling cone (theta c, degree). The values of Dw and theta c measured for NBD-PE embedded in bovine brain phosphatidylserine bilayers were 3.7 x 10(7) s-1 and 46 degrees in the absence of divalent cations at 25 degrees C. When 3 mM of Ca2+ was added, both Dw and theta c distinctly dropped to 1.7 x 10(7) s-1 and 38 degrees, respectively. By the addition of 3 mM of Mg2+, however, only Dw decreased to 2.7 x 10(7) s-1 and theta c remained unchanged. These results show that both Ca2+ and Mg2+ decrease the rate of motion at the head part in PS molecules, but only Ca2+ narrows the distance between the neighboring head groups. Since Mg2+ does not promote vesicle fusion, it appears that the deformation at the head group region in the bilayer structure induced by Ca2+ is an important step in the membrane fusion process.

Effect of NO synthase inhibition on behavioral changes induced by a single administration of methamphetamine

The present study examined the effects of nitric oxide synthase inhibitor, N omega-nitro-L-arginine methyl ester (L-NAME; 10, 30, 60 mg/kg, i.p.) on behavioral changes induced by a single administration of methamphetamine (MA) (3.22 and 0.805 mg free base/kg, s.c.). MA increased locomotion-stereotypy rating scores and motor activity counts measured by an infrared sensor. L-NAME administered prior to MA significantly decreased the level of locomotion stereotypy rating and motor activity induced by MA. An inactive optical isomer, N omega-nitro-D-arginine methyl ester (D-NAME) had no effects on MA-induced behavioral changes. The results suggest that NO synthesis is involved in the full expression of behavioral effects of MA.

[Cervical myelopathy from an aspect of a neurological surgeon]

More than 65 per cent of intramedurally tumors and intradural extramedurally tumors were located in cervical region. They enact a cause of cervical myelopathy. A special attention should be paid to solitaly intramedurally vascular malformations, when the patients show an acute progressive myelopathy. In very rare cases of syringomyelia, intramedurally tumors such as hemangioblastoma or ependymoma could be found, so that enhanced MRI or angiography should be done if necessary. In cases of a herniated disc, cervical spondylosis and OPLL, the distance between articulo-pillar line and spinolaminal line must be measured. If the distance of both lines is near or the same, that means narrow cervical canal. In rare cases the form of the vertebral body is round. This is a rare cause of a type of narrow canal.

Epididymis metastasis from colon carcinoma: a case report and a review of the Japanese literature

A 56-year-old Japanese man in whom a descending colon carcinoma had been resected underwent a high orchitectomy for metastatic epididymis from the colon. Metastatic carcinoma from the digestive organs to the spermatic cord (SC) and/or the intrascrotal contents (ISC) is rare. Fifty-four Japanese patients with metastasis from the digestive organs to the SC and/or the ISC were analyzed. The most frequent primary site was the stomach and the most frequent metastatic site was the spermatic cord. Our patient was the first to exhibit metastasis from the colon to the epididymis. A primary site was identified in 24 patients subsequent to the metastatic tumor. Twenty patients had other organ metastasis. The prognosis for SC and/or ISC metastasis patients is poor. Our patients has survived for 18 months following his orchitectomy with no other organ metastasis (31 months after the primary operation). In our patient, monoclonal estrogen receptor staining was negative; however, further study must be undertaken.

Regional changes in dopamine and serotonin activation with various intensity of physical and psychological stress in the rat brain

The present study examined whether regional patterns of brain dopamine (DA) and serotonin (5-HT) activation after physical and psychological stress depend on the intensity of that stress. Monoamine concentrations (DA, 5-HT, and their metabolites) were measured using high-performance liquid chromatography with electrochemical detection in eight brain regions of rats exposed to two different intensities of foot shock stress for 30 min (1.5 mA or 2.5 mA) or conditioned fear stress (CFS, after single or repeated foot shock). A low level of foot shock selectively increased the DA metabolism in the medial prefrontal cortex (mPFC), whereas a high level of foot shock increased it in most of the brain regions examined in the present study. A low level of foot shock did not increase the 5-HT metabolism in any regions, but a high-intensity shock increased the 5-HT metabolism in the mPFC, nucleus accumbens, and lateral hypothalamus. Rats that received high-intensity shock displayed more freezing than those that received low-intensity shock in a conditioned fear paradigm (24 h after receiving foot shock, the animals were placed in a shock chamber without being given shock), indicating an augmentation of conditioned fear. The increased DA and 5-HT metabolism were especially marked in the mPFC after CFS following a single foot shock session (2.5 mA). Rats that were repeatedly exposed to 2.5 mA foot shock for a period of 10 days displayed a greater degree of freezing induced by CFS than those given only one foot shock session, indicating an augmentation of fear and stress intensity. CFS after repeated foot shock, like foot shock per se, increased the DA metabolism in most of the brain regions except for the striatum and increased the 5-HT metabolism in the mPFC, nucleus accumbens, and amygdala. These results suggest that regional patterns of brain DA and 5-HT activation after physical and psychological stress depend on the intensity of that stress, although there are some differences between these stress; and that the more widespread activation of DA and 5-HT after more severe stress might relate to behavioral changes that reflect the augmentation of fear.

[A rare case of high cervical spinal cord dural arteriovenous fistula presenting with intracranial subarachnoid hemorrhage]

It is now recognized that spinal dural arteriovenous fistula causes myelopathy, resulting from congestive venous hypertension of the spinal cord. We have recently encountered a rare case of high cervical spinal cord dural arteriovenous fistula which caused intracranial subarachnoid hemorrhage. The patient was a 62-year-old female, who had exhibited an abrupt onset of severe headache and loss of consciousness. Plain head CT scan revealed intracranial subarachnoid hemorrhage. No abnormal vascular lesions were found on the first cerebral angiography. The second angiographical examination demonstrated a spinal arteriovenous malformation at the high cervical region. A dural arteriovenous fistula around the right C2 nerve root was found by surgical intervention. The fistula was recognized between rt. C2 radicular artery and dural sheath of rt. C2 nerve root, draining to the epidural plexus and intradural local medullary vein. No serpentine coronal venous plexus on the dorsal aspect of the cervical cord was seen as it is in a usual dural type of spinal arteriovenous fistula. The bleeding point was an intradural varix of the medullary vein just where it penetrated the nerve root area. Feeder ligation of the C2 radicular artery and coating of the varix complex were performed. The postoperative course was uneventful. The patient was discharged from our institute with no neurological deficits.

All-trans retinoic acid upregulates thrombomodulin and downregulates tissue-factor expression in acute promyelocytic leukemia cells: distinct expression of thrombomodulin and tissue factor in human leukemic cells

The expressions of thrombomodulin (TM) and tissue factor (TF) by all-trans retinoic acid (ATRA) were studied in human leukemic cell lines including NB4 (acute promyelocytic leukemia) and U937 (monoblastic leukemia). ATRA remarkably upregulated TM antigen expression in cell lysates as well as TM cofactor activity on the cell surfaces of NB4. The level of TM mRNA in NB4 cells was increased by ATRA. Inherently procoagulant NB4 cells contained markedly higher content of TF, which was efficiently reduced by ATRA. Modest increase of TM and decrease of TF were observed when NB4 cells were treated with dibutyryl cyclic adenosine monophosphate (dbcAMP). On the other hand, both ATRA and dbcAMP showed dramatic increase of TM antigen level and modest decrease of TF antigen in U937 cells. These results suggest that ATRA regulates expressions of TM and TF antigens and activity in NB4 and U937 cell lines, and provide evidence for a potential efficiency of ATRA as a preventive and therapeutic agent for disseminated intravascular coagulation in promyelocytic and monocytic leukemia.

Structural and functional roles of the cysteine residues of Bacillus stearothermophilus farnesyl diphosphate synthase

p-(Chloromercuri)benzoic acid inhibited the catalytic activity of Bacillus stearothermophilus farnesyl diphosphate synthase (FPP synthase), which contains only two cysteine residues at positions 73 and 289. In order to explore the role of the cysteine residues, either or both of them were replaced with phenylalanine or serine. Five mutant enzymes, C73F, C73S, C289F, C289S, and C73S-C289S, were overproduced in Escherichia coli and purified to homogeneity. All of them were active as farnesyl diphosphate synthase, showing specific activities comparable to that of the wild-type enzyme. These results indicate that neither of the cysteines is essential for catalytic function. The C73F mutant, however, was very sensitive to heat treatment, while C73S was as highly stable as the wild type. The Km value of C289F for isopentenyl diphosphate is 10 times that of the wild type. The wild-type enzyme was converted into an oxidized form which was separable from the native enzyme on ion-exchange chromatography, and this conversion was accelerated by cupric ions. Similar conversion has previously been reported by several researchers, who found the occurrence of two forms of pig liver FPP synthase and who attributed this phenomenon to the oxidoreduction of sulfhydryl and disulfide groups. However, even the C73S-C289S mutant, which has no cysteine residues, was also converted into an oxidized form as in the case of the wild-type enzyme. These results provide evidence that residues other than cysteine are involved in the conversion of this enzyme into the oxidized form.

Inhibitory effects of prostacyclin analogue, TFC-132, on aortic neointimal thickening in vivo and smooth muscle cell proliferation in vitro

Effects of a new prostacyclin analogue, TFC-132, on neointimal thickening following intimal mechanical injury and on the proliferation of cultured aortic smooth muscle cells (SMCs) were studied. The intimal injury was induced by indwelling of polyethylene tubing for 24 h in the rabbit aorta. Rabbits were killed 10 days after drawing out the tubing. TFC-132 (0.6 mg/kg or 1.2 mg/kg) was given orally at 8-h intervals through the experiment. The serum concentrations of the analogue rose significantly 1 and 2 h after administration. The mean intimal thickening in the TFC-132 treated groups was significantly thinner than in the control one. Human aortic SMCs were cultured and 3H-thymidine incorporation into DNA (DNA synthesis) was measured at the varying concentrations of TFC-132. The analogue inhibited DNA synthesis of cultured SMCs at 10(-6) and 10(-5) M. These data indicate that a new prostacyclin analogue, TFC-132, has an inhibitory effect on the neointimal thickening after intimal injury and on the aortic SMC proliferation.

Thermostable farnesyl diphosphate synthase of Bacillus stearothermophilus: crystallization and site-directed mutagenesis

The gene for thermostable farnesyl diphosphate synthase from Bacillus stearothermophilus was cloned, sequenced, and overexpressed in Escherichia coli. The synthase was purified to homogeneity and crystallized. The enzyme carried only two cysteine residues in contrast to its counterparts from other sources, which have four to six cysteine residues. Either or both of the cysteine residues can be replaced with serine without causing a loss of the catalytic activity. The conserved arginine residue that occupies the third position from the C-terminus was also replaced with valine without significant loss of activity, but the valine mutant showed a weakened affinity for isopentenyl diphosphate.