Intracellular retention and degradation of tissue-nonspecific alkaline phosphatase with a Gly317-->Asp substitution associated with lethal hypophosphatasia

One point mutation which converts glycine-317 to aspartate of tissue-nonspecific alkaline phosphatase (TNSALP) was reported to be associated with lethal hypophosphatasia (Greenberg, C. R., et al. Genomics 17, 215-217, 1993). In order to define the molecular defect of TNSALP underlying the pathogenesis of hypophosphatasia, we have examined the biosynthesis of TNSALP with a Gly317-->Asp substitution. When expressed in COS-1 cells, the mutant did not exhibit alkaline phosphatase activity at all, indicating that the replacement of glycine-317 with aspartate abolishes the catalytic activity of TNSALP. Pulse-chase experiments showed that the newly synthesized mutant failed to acquire Endo H-resistance and to reach the cell surface. Interestingly, this TNSALP mutant was found to form a disulfide-bonded high-molecular-mass aggregate and was rapidly degraded within the cell, though the mutant protein was modified by glycosylphosphatidylinositol (GPI). Lactacystin, an inhibitor of the proteasome, obstructed the degradation of the mutant protein, suggesting the involvement of proteasome as a part of quality control of TNSALP.

Effects of OG-VI, a nucleoside/nucleotide mixture, on stunned myocardium in dogs: is the adenosine A1 receptor involved?

BACKGROUND

OG-VI is a solution composed of 30 mmol/l inosine, 30 mmol/l sodium 5'-guanylate, 30 mmol/l cytidine, 22.5 mmol/l uridine and 7.5 mmol/l thymidine; it limits myocardial stunning in dogs. We examined whether adenosine A1 receptors were involved in the mechanism of action of OG-VI.

METHODS

Dogs anesthetized with pentobarbital were subjected to 20 min of left anterior descending coronary artery ligation followed by 30 min of reperfusion. Saline, OG-VI in several doses, adenosine or inosine was infused at 0.1 ml/kg/min, starting 30 min before the ischemia. In some experiments, 1 or 3 mg/kg 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), a selective adenosine A1 receptor antagonist, was injected intravenously 15 min before the start of the OG-VI infusion. The percentage myocardial segment shortening (%SS) was measured by sonomicrometry. The tissue concentration of ATP was measured in the 30-min-reperfused hearts.

RESULTS

In the saline group, %SS that had been decreased by ischemia returned toward pre-ischemic values after reperfusion, although the metabolic recovery was incomplete, with a low concentration of ATP. The %SS was almost completely restored by 12 and 1.2 mumol/kg/min OG-VI, but 0.4 mumol/kg/min was less effective. Administration of adenosine or inosine did not modify the changes in %SS during ischemia/reperfusion. Pretreatment with DPCPX worsened the recovery of %SS during reperfusion after ischemia in both the saline and the OG-VI groups. Infusion of DPCPX (3 mg/kg) with saline caused the animals to die shortly after the onset of ischemia. However, the enhancement of %SS recovery during OG-VI reperfusion was observed in the presence of DPCPX.

CONCLUSION

OG-VI improves the recovery of %SS during reperfusion after brief ischemia in a dose-dependent manner. This effect is not brought about by stimulation of adenosine A1 receptors.

Morphological examination of bone synthesis via direct administration of basic fibroblast growth factor into rat bone marrow

Woven bone induced by direct injection of basic fibroblast growth factor (bFGF) into rat bone marrow was examined. On the first day after injection, fibrous tissues formed in the treated region of the bone marrow. Tissue-nonspecific alkaline phosphatase (TNAPase)-immunopositive osteoblastic cells and osteopontin immunopositive-extracellular matrices were observed in the fibrous tissues, indicating bone induction. On the fifth day, the bFGF-induced bone was found broadly in the bone marrow. In the originally existing bone, osteopontin-immunoreactivity was observed at cement lines, but not in the fully calcified matrix, whereas the woven bone displayed immunoreactivity throughout the matrix. Numerous TRAPase-positive osteoclasts were present on the surfaces of the woven bone, but no obvious cement line was observed. Therefore, both bone formation and resorption appeared highly active, without normal cellular coupling equilibrated between bone formation and resorption performed by osteoblasts and osteoclasts. On the tenth day, the bFGF-induced bone was almost replaced by bone marrow. Thus, bone formation actively occurred in the first half of the experimental period, whereas bone resorption came to be predominant thereafter. This study demonstrated that bFGF stimulates bone formation, which, however, is subject to subsequent resorption, probably due in part to the absence of coordinated cellular coupling between osteoclasts and osteoblasts.

Detection of platelets activated during acetylcholine-induced coronary vasospasm

Although platelet activation may play a role in coronary artery spasm, platelets activated following coronary vasospasm have not been clinically detected. We performed flow cytometric analysis of activation-dependent granular proteins, CD62P (P-selectin), CD63, PAC-1 (activated glycoprotein [GP] IIb/IIIa) and thrombospondin on the platelet plasma membrane in patients who exhibited acetylcholine-induced coronary vasospasm and compared findings with those in control patients without vasospasm. We simultaneously investigated the plasma levels of thrombin anti-thrombin III complex (TAT), plasmin alpha2-plasmin inhibitor complex (PIC), and thrombomodulin. In patients with vasospasm, the expression of CD62P, CD63 and PAC-1 on the platelet membrane surface increased in coronary sinus blood samples following coronary vasospasm, although the expression in aortic samples did not change. The TAT level also increased in the coronary sinus after vasospasm. Platelets might be activated by coronary vasospasm within the coronary circulation. The platelet activation process may be modulated by thrombin generation.

Effects of azelnidipine, a dihydropyridine calcium antagonist, on myocardial stunning in dogs

Effects of azelnidipine, a dihydropyridine derivative, on stunned myocardium were examined in anesthetized open-chest dogs. The left anterior descending (LAD) coronary artery was ligated for 20 min and then released for 60 min. Dimethyl sulfoxide (DMSO), the solvent of azelnidipine, or azelnidipine (0.03, 0.1 or 0.3 mg/kg) was injected i.v. 20 min before ligation. Segment shortening was determined by sonomicrometry. The levels of high-energy phosphate were measured in 60-min reperfused hearts. Azelnidipine at 0.1 and 0.3 mg/kg significantly decreased diastolic blood pressure and increased % segment shortening. The increase in % segment shortening due to azelnidipine appeared to be abolished by propranolol and atropine pretreatment. Ischemia significantly decreased % segment shortening in all groups. The % segment shortening that had been decreased by ischemia recovered during reperfusion, but did not reach its preischemic level in each group. In the 0.1 and 0.3 mg/kg of azelnidipine-treated dogs, a significant enhancement of % segment shortening recovery during reperfusion was observed, as compared with that in the DMSO-treated dogs. Azelnidipine did not affect the high-energy phosphate levels in 60-min reperfused hearts. In conclusion, azelnidipine improved the contractile dysfunction in stunned myocardium, without any preservation of high-energy phosphate.

The multiple untranslated first exons and promoters system of the oestrogen receptor gene in the brain and peripheral tissues of the rat and monkey and the developing rat cerebral cortex

Recent studies on the human oestrogen receptor (ER) gene have revealed the complex system with the multiple untranslated first exons and promoters in the ER gene expression. Little information is however available on the system in the ER gene of the rat or nonhuman primate. The rat genomic library was first screened by the rat ER cDNA (0-1) probe. One of the four positive clones (lambda rEgE1) was subcloned and sequenced. The nucleotide sequence was found to contain the exon 0, the intron 0, and the exon 1 with its 3'-ends. The novel untranslated first exons, the exon ON and the exon OS, were further identified. These results indicated the presence of at least four subtypes of the rat ER mRNAs; the messages transcribed from promoter P-0 (ER mRNA (0-1)), putative promoter P-1 (ER mRNA (1-1)), promoter P-ON (ER mRNA (ON-1)) and promoter P-OS (ER mRNA (OS-1)). The P-O- or P-1 driven message (0-1) or (1-1) appeared to be expressed most strongly in major oestrogen central- (anterior pituitary, AP, hypothalamus-preoptic area, HPOA, and amygdala, AMG) and peripheral targets (uterus and ovary). The message (ON-1) was strongly expressed in the liver and kidney, but not in the HPOA, AMG, cerebral cortex, CC, and cerebellum, Ce. The OS-1 message was expressed variably but generally in the tissues examined except for the CC and Ce. Thus, the region- and tissue specific expression of the rat ER gene is likely to be regulated by the multiple untranslated exons and promoters system. Furthermore, when the ER mRNA subtypes were examined in the rat neonatal CC where the ER protein level rose transiently, considered as a model for the development of the ER or progestin receptor A and B isoforms, the expression of the ER mRNAs seemed to be differential postnatally, implicating some stage dependent usage of the promoters in the development. In the monkey, we identified the untranslated first exon OS, the homologue of the rat exon OS. Interestingly, the exon C was found to consist of two different exons, the exon OK and the exon OG. By the alternative usage of the promoters and the alternative splicing, at least six ER mRNA subtypes, that is, ER mRNAs (0-1), (1-1), (OS-1), (OS-OG-1), (OK-1) and (OK-OG-1) were identified in the monkey tissues. These messages were also differentially distributed in the monkey brain and other tissues. It was noteworthy that the P-OK driven messages were expressed almost exclusively in the monkey liver. These results have suggested that the systems of the multiple untranslated first exons and promoters and the alternative splicing are involved in the regulation of the region- and tissue specific expression of the ER gene in the brain and peripheral tissues of the rat and monkey. Stage-related usage of the promoters was also suggested in the ER gene expression in the CC of the postnatal rat in development.

[A case report of epidural abscess due to anaerobic bacteria, producing a mass of gas]

A 54-year-old female was admitted to our hospital on May 8, 1996, for evaluation of fever and headache. Her cerebrospinal fluid showed elevation of the cell count and total protein. The thoracic and lumbar MRIs revealed abnormal gas occupying the epidural space at the sacral level, and extended as high as 9th thoracic level. The gas spread inside the iliopsoas and paraspinal muscles. Anaerobic bacteria such as Bacteroides fragilis and Peptostreptococcus productus were cultured from the spinal fluid and Bacteroides was also detected from the epidural tissues obtained during laminectomy. The infectious source was decubitus extending around the sacral bone. The combination therapy of debridement with peroxide, catheter drainage of epidural abscess, intravenous and intrathecal antibiotics, and laminectomy presented her good outcome. This is a rare case of anaerobic bacterial spinal abscess, showing epidural and intramuscular gas as a prominent feature.

Successful treatment of infertility due to anejaculation with in vitro fertilization and embryo transfer: a report of two cases

We investigated the efficacy of assisted ejaculation in combination with in vitro fertilization and embryo transfer (IVF-ET) in two couples with infertility due to anejaculation. Case 1 was in an anejaculatory condition associated with a spinal cord-injury. We performed intrauterine insemination (IUI) three times using motile sperm obtained by intrathecal injection of neostigmine, but no pregnancy followed. The couple then entered IVF-ET. The semen volume obtained by assisted ejaculation was 4.5 ml. The sperm count was 33 x 10(6)/ml with 33% motility. At 35 weeks of gestation she delivered three healthy babies by cesarean section. Case 2 was in an unexplained retrograde ejaculatory condition. We performed IUI eight times before changing to IVF-ET. We then used sperm obtained from urine or sperm recovered from the bladder after administration of human tubal fluid, but no pregnancy followed. At the fifth IVF-ET attempt, using sperm obtained from urine, we succeeded. We prepared the sperm by the Percoll gradient method. The sperm count was 36 x 10(6)/ml with 64% motility. At 39 weeks of gestation she delivered a healthy baby. Deficient seminal quality contributes to the decreased fertility potential in patients with anejaculation. With the use of IVF-ET methods, pregnancies can be achieved in these couples.

Serum concentration of the pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP) is a useful indicator of decline and recovery of bone mineral density in lumbar spine: analysis in Japanese postmenopausal women with or without hormone replacement

To reassess the clinical utility of serum pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP), a promising but controversial indicator of bone resorption, we evaluated its performance as a biochemical marker in a 6-month study of a strictly selected population of 76 Japanese postmenopausal and healthy women, 33 recipients of hormone replacement therapy and 43 nonrecipients. We measured bone mineral density (BMD) of the lumbar spine (L2-L4), and serum ICTP, carboxyterminal propeptide of type I procollagen (PICP) and other conventional serum biochemical markers, e.g. bone gla protein (BGP), alkaline phosphatase, calcium and phosphate at the entry and 6 months later. We calculated the percent change between the baseline and 6-month values (delta%) in lumbar BMD and the biochemical markers, individually, and compared the degree of correlations between delta% in BMD and that in the biochemical markers. Delta% in ICTP and delta% in BGP correlated with delta% in BMD negatively and significantly. Especially delta% in ICTP correlated with that in BMD to a high degree (P<0.0001). No significant correlation was observed in other biochemical markers. We concluded that serum ICTP is a sensitive and useful bone resorption marker in the postmenopausal population, which strongly correlates with the change in BMD.

Clinical significance of neutrophil adhesion molecules expression after coronary angioplasty on the development of restenosis

To investigate the neutrophil activation process following percutaneous transluminal coronary angioplasty (PTCA), we examined the expressions of Mac-1 (CD11b/CD18), L-selectin (CD62L), and sialyl-LewisX (SLX) on the surface of neutrophils after the PTCA procedure, by flow cytometric analysis. Twenty-nine patients with single vessel coronary artery disease of the left anterior descending artery who underwent elective PTCA were enrolled. In the 17 patients without restenosis at the follow-up angiography, the mean channel fluorescence intensity (MFI) for CD18, CD62L and SLX did not change after PTCA. Only the CD11b level was increased at 48 h after the PTCA. In the remaining 12 patients who developed restenosis, the MFI values for CD18 and CD11b were increased at 24 h and 48 h after the PTCA. The MFI value for CD62L was decreased and that for SLX was increased at 48 h after the PTCA. These changes were more prominent in the coronary sinus blood samples than in those of the peripheral blood samples. Our data indicate the down-regulation of L-selectin, probably by shedding, as well as the up-regulations of Mac-1 and sialyl-LewisX, especially in patients with restenosis. It is suggested that neutrophil activation by an interaction between the selectin family and carbohydrate ligands after PTCA may play a role in the development of restenosis, as does the integrin family.

Tricuspid valve infectious endocarditis associated with dental treatment

A 52-year-old man with neither congenital heart disease nor history of drug abuse had a spiking fever after dental treatment and was diagnosed with pneumonia at a local clinic. He was treated with antibiotics and his fever went down. Ten months later, he had again pyrexia and suffered from congestive heart failure. He admitted to our hospital and tricuspid valve endocarditis was proved by echocardiography. He was treated with penicillin. However, during the treatment, he developed a pulmonary embolism. So he underwent surgical treatment. We should take dental treatment into account one of predisposing causes of tricuspid endocarditis.

[The efficacy of postural drainage in a case of pulmonary edema following cholecystectomy]

An 81-year-old man underwent percutaneous transluminal gallbladder drainage. As the drain was accidentally removed six days later, he received cholecystectomy. After the operation, he developed hypotension, hypoxemia and ST level depression on ECG. He received artificial ventilation and cathecholamines. His chest CT showed marked pulmonary edema, and total protein of the edema-fluid was 3.3 g.dl-1. These findings suggested permeability pulmonary edema. He received postural drainage of the edema-fluid, and the pulmonary oxygenation was gradually improved. He was weaned from artificial ventilation on the 6th ICU day and discharged the next day.

Lipid peroxidation in the pancreas and other organs in streptozotocin diabetic rats

We studied the relationship between changes in lipid peroxides and those in catalase activity in pancreases, livers and hearts of streptozotocin-induced diabetic rats. Animals were killed 2 or 7 weeks after saline or streptozotocin (32 mg/kg, i.v.) injection. The levels of blood glucose and plasma insulin in the 2-week streptozotocin-treated rats were 176.8+/-20.5 mg/dl and 29.9+/-3.2 microU/ml, respectively. In the pancreas, the lipid peroxide level significantly decreased and the catalase activity significantly increased 2 weeks after streptozotocin injection. These changes recovered after 7 weeks. In the heart, the lipid peroxide level significantly increased without any change of catalase activity 2 weeks after the initiation of diabetes. After 7 weeks, the catalase activity significantly increased and the lipid peroxide level returned to the control level. In the liver, there was no change in the lipid peroxides and catalase in the 2-week streptozotocin-treated rats, whereas the catalase activity significantly increased 7 weeks after the injection. It was suggested that the defense system in the pancreas to oxidative stress may be evoked in an early stage of streptozotocin-induced diabetes.

Improvement of impaired glucose tolerance by oral administration of vanadyl sulfate by gavage in streptozotocin-induced diabetic rats

We examined the effect of oral administration of vanadyl sulfate by gavage on the levels of blood glucose and plasma insulin during oral glucose tolerance test (OGTT) in diabetic rats. Diabetes was induced by intravenous injection of streptozotocin at the dose of 32 mg/kg. Nondiabetic control animals were injected with an equal volume of saline. Vanadyl sulfate at a dose of 25, 50, or 75 mg/kg was given orally by gavage for 2 weeks, starting 12 hours after streptozotocin injection. When vanadyl sulfate was given twice a day, half of the one-day-dosage was given in the morning and the remaining half in the evening. Glucose tolerance test with 5 g/kg of glucose was carried out 2 weeks after administration of vanadyl sulfate. The fasting the blood glucose level in the diabetic rats was higher than that in the non-diabetic rats, whereas the plasma insulin level in the diabetic rats was lower. An increase in blood glucose seen in the glucose tolerance test was significantly greater in the diabetic rats than in the non-diabetic rats. The level of plasma insulin was increased by glucose tolerance test in the non-diabetic rats, while it was not changed in diabetic rats. Oral administration of vanadyl sulfate by gavage significantly improved the impaired glucose tolerance in the the diabetic rats in a dose-dependent manner without any change in plasma insulin level. In conclusion, oral administration of vanadyl sulfate by gavage is effective on impaired glucose tolerance in streptozotocin-induced diabetic rats.

The prognosis of fetuses with a shortened femur and humerus length before 20 weeks of gestation

OBJECTIVE

The purpose of this study was to evaluate the prognosis of fetuses with a shortened femur and humerus length detected at earlier than 20 weeks of gestation.

METHODS

The study population consisted of 549 Japanese pregnant women. The prognosis of the shortened femur and humerus length fetuses was evaluated and the predictivity of the shortened femur and humerus length for chromosomal abnormalities and structural malformations was also calculated.

RESULTS

All seven shortened femur and humerus length fetuses had some kind of structural malformations and three fetuses also had chromosomal abnormalities. The detection rate, positive predictive value and false positive rate for structural malformations were 17.9%, 100% and 0%, respectively. The positive predictive value for chromosomal abnormalities was 43%.

CONCLUSION

The shortened femur and humerus length fetuses in Japanese women demonstrated an increased risk of structural malformations, especially in the cardiovascular system, as well as chromosomal abnormalities.

[Male sterility]

Recently several studies have suggested a decline in the quality of semen. About half of the infertile causes are in men, the rate is increasing in the infertile couples. There are some therapy for the male sterility; medication, surgery or assisted reproductive technology (ART). Medicinal effects are not expected, and surgical cases are localized for indication. Moreover, since most of male sterility are idiopathic insufficiency of spermatogenesis, a recent tendency in the male sterile therapy is ART such as IVF-ET, ICSI, TESE, etc.

The prognosis of fetuses with transient nuchal translucency in the first and early second trimester

OBJECTIVE

The purpose of this study was to evaluate the prognosis of fetuses with transient nuchal translucency before 15 weeks of gestation.

STUDY DESIGN

A nuchal translucency's measurement of > or = 5 mm was considered abnormal. In the period from 1994 to 1995, twelve fetuses were diagnosed at our institution with nuchal translucency. The fetuses all underwent karyotyping and a complete ultrasonographic search for any associated anomalies and a resolution of nuchal translucency at 1-2 week gestational age intervals.

RESULTS

Five cases ('Transient NT') demonstrated transient nuchal translucency. Seven cases ('Persistent NT') demonstrated persistent nuchal translucency. The 984 cases with no or less than 5 mm of nuchal translucency (control group) gave birth at the same time. The mean initial week of diagnosis was 12.0 +/- 1.6 weeks in 'Transient NT', and 13.6 +/- 1.8 weeks in 'Persistent NT'. The mean maternal age was 30.8 +/- 6.3 years old in 'Transient NT', 28.9 +/- 3.0 years old in 'Persistent NT', and 30.5 +/- 43 years old in the control group. Abnormal karyotypes were detected in one case in 'Transient NT', and in four cases in 'Persistent NT'. Structural malformations were detected in two cases (40%) in 'Transient NT', seven cases (100%) in 'Persistent NT', and 30 cases (3.0%) in the control group.

CONCLUSIONS

Regardless of the spontaneous resolution of abnormal nuchal translucency, there was a high association with both karyotypical and structural abnormalities, and the prognosis of such cases was generally poor, especially persistent NT's prognosis.

[Successful treatment of interstitial pneumonia with lipo-PGE1 and pentoxifylline in a patient with dermatomyositis]

Interstitial pneumonia complicated with dermatomyositis sometimes shows a resistance to high dose steroid therapy and a fatal course particularly in patients without showing the elevation of creatine kinase. We experienced a 48 year old woman who developed heliotrope rash, Gottron's sign, multiple cutaneous ulcers, and dyspnea on exertion. These symptoms were resistant to low dose steroid therapy. Serum levels of creatine kinase were normal. Anti-nuclear antibodies and anti-Jo-1 antibody were negative. High resolution CT scan of the chest showed areas of multiple air space consolidation and subpleural linear shadows. Lung biopsy performed under video-assist thoracosurgery revealed diffuse alveolitis with scattered lymphoid folicules and mild accumulation of macrophages in the alveolar spaces. There were no honey-combing. These features were compatible with "non-specific interstitial penumonia" proposed by Katzenstein, 1995. The patient was treated with 10 micrograms lipo-PGE1, PGE1 incorporated in lipid microspheres, and 300 mg pentoxifylline, which resulted in a dramatic improvement of both interstitial pneumonia and cutaneous ulcers. The present case suggested a novel strategy for the treatment of interstitial pneumonia.

Inhibitory effects of glibenclamide and pertussis toxin on the attenuation of ischemia-induced myocardial acidosis following ischemic preconditioning in dogs

Ischemic preconditioning is known to be mediated by several humoral factors, such as adenosine, norepinephrine, and bradykinin. We examined intracellular signal transduction of ischemic preconditioning following receptor stimulation. Alterations in the pH of the ischemic bed were monitored to assess the response of control and ischemic-preconditioned myocardium to glibenclamide and pertussis toxin. Pentobarbital-anesthetized open-chest dogs were subjected to 40 min of ligation of the left anterior descending coronary artery. Ischemic preconditioning was elicited by 25-min periods of coronary ligation followed by 5 min of reperfusion before a 40-min period of ligation. Glibenclamide (0.3 mg/kg)was given i.v. 20 min before the onset of ischemic preconditioning. Pertussis toxin (6-10 micrograms/kg) was given i.v. 3 days before the experiment. Tissue myocardial pH was measured by a glass micro-pH electrode. Ischemia for 5 min decreased myocardial pH and reperfusion returned it to the preischemic levels. Ischemia for 40 min decreased the myocardial pH from 7.43 +/- 0.06 to 6.43 +/- 0.08. Ischemic preconditioning significantly attenuated the decrease in myocardial pH (6.57 +/- 0.06) induced by 40 min of ischemia. Pretreatment with either glibenclamide or pertussis toxin completely abolished the effect of ischemic preconditioning on ischemic myocardial acidosis. Ischemic preconditioning can attenuate ischemia-induced myocardial acidosis in dogs, and this effect is mediated by activation of adenosine triphosphate-sensitive potassium channels and pertussis toxin-sensitive guanosine triphosphate-binding protein.

Glutamate in opioid dependence

The present review will concentrate on a discussion of recent investigations which implicate a critical linkage of three facets of the central nervous system mediation of opioid dependence, as evidenced by expression of acutely-precipitated withdrawal events. These are the kappa-opioid receptor subtype, the glutamatergic neuronal system and a specific brain locus, the locus coeruleus. The impetus for this line of investigation derives from a recognition that opioid analgesics, such as butorphanol (Stadol), exhibit a markedly different profile of activity at opioid receptors than does morphine yet have abuse liability and cause dependence readily. Emphasis will be placed on demonstration of a rodent model in which butorphanol administration induces dependence through a unique (in comparison with morphine) activation of the kappa-opioid receptor. The use of in vivo microdialysis techniques clearly identifies, in this model, that acutely-precipitated withdrawal from dependence on butorphanol results in focal increases in extracellular levels of glutamate within the locus coeruleus, and that the withdrawal syndrome can be mimicked by intracerebroventricular administration of exogenous glutamate, acting through the N-methyl-D-aspartate glutamate receptor subtype. The data confirm the participation of glutamate as a general phenomenon in opioid dependence, identify the locus coeruleus as a primary site for glutamatergic mediation of dependence, and suggest novel aspects to the neuropharmacology of opioid dependence with respect to the role of the kappa-opioid receptor.

Fibroblasts of spinal ligaments pathologically differentiate into chondrocytes induced by recombinant human bone morphogenetic protein-2: morphological examinations for ossification of spinal ligaments

To elucidate the process of ossification in spinal ligaments, an aqueous solution containing recombinant human bone morphogenetic protein (BMP)-2 (40 micrograms/100 microL) was injected into murine ligamenta flava, and the ossification process was analyzed morphologically. In the control group, the solution administered lacked the protein; these flattened ligamentous fibroblasts possessing BMP receptors type IA and type II existed among type I collagen bundles. In the week immediately following the injection of BMP-2, ligamentous fibroblasts began to proliferate, differentiating into alkaline phosphatase-positive chondrocytes surrounded by an extracellular matrix composed of type I and II collagen. By the second week, differentiated chondrocytes of various stages were observed in type II collagen-rich matrix. These chondrocytes showed an abundance of BMP receptors type IA and II. The pathologically induced cartilage was resorbed by chondroclasts, permitting migration of blood vessels and osteogenic cells, as well as providing a site for endochondral ossification. By the third week, BMP-induced ossification had compressed the spinal cord, and by the sixth week, the ligamentous tissue had been almost completely replaced by bone. Ligamentous fibroblasts appeared to possess BMP receptors, as well as the potentiality to differentiate into chondrocytes. BMP receptors were upregulated during chondrification of ligamentous fibroblasts induced by exogenous BMP-2, suggesting that BMPs may play an important role in ossification of spinal ligaments.

Role of NMDA receptors in pentobarbital tolerance/dependence

Effects of continuous pentobarbital administration on binding characteristics of [3H]MK-801 in the rat brain were examined by autoradiography. Animals were rendered tolerant to pentobarbital using i.c.v. infusion of pentobarbital (300 micrograms/10 microliters/hr for 7 days) by osmotic minipumps and dependent by abrupt withdrawal from pentobarbital. The levels of [3H]MK-801 binding were elevated in rats 24-hr after withdrawal from pentobarbital while there were no changes except in septum and anterior ventral nuclei in tolerant rats. For assessing the role of NMDA receptor in barbiturate action, an NMDA receptor antagonist (MK-801, 2.7 femto g/10 microliters/hr) was co-infused with pentobarbital. The pentobarbital-infused group had a shorter duration of pentobarbital-induced loss of righting reflex (sleeping time) than that of the control group, and MK-801 alone did not affect the righting reflex. However, co-infusion of MK-801 blocked hyperthermia, and prolonged the onset of convulsions induced by t-butylbicyclophosphorothionate (TBPS) in pentobarbital withdrawal rats. In addition, elevated [35S]TBPS binding was significantly attenuated by co-infusion with MK-801. These results suggest the involvement of NMDA receptor up-regulation in pentobarbital withdrawal and that the development of dependence can be attenuated by the treatment of subtoxic dose of MK-801.