[Measurement of thrombomodulin values in the serum and eyes of experimental autoimmune uveoretinitis]

Thrombomodulin (TM) is a protein, present on intact endothelial cell surfaces, that plays a major role in the protein C anticoagulant system. Plasma TM is produced by injured endothelium, and is recognized in circulating blood or urine as a sign of endothelium cell damage. The localization of TM within the eye and its kinetics in the eye and the serum were investigated in rats with experimental autoimmune uveoretinitis (EAU). An immuno-histochemical study showed the presence of TM at sites of fibrin in the anterior chamber and retinal vasculitis. The amount of TM in the eye increased with progression of intraocular inflammation, but the serum level of TM did not significantly differ from the values in the control group. These data suggest that TM may play a role in preventing thrombosis in cases of vasculitis and fibrin formation in the anterior chamber in EAU, thus maintaining blood flow and the fluidity of aqueous humor.

Cytochrome P450 side-chain cleavage enzyme in the cerebellar Purkinje neuron and its neonatal change in rats

Neurosteroids are de novo synthesized in the nervous system through mechanisms at least partly independent of peripheral steroidogenic glands. However, the concept of neurosteroidogenesis in neurons is not clear in mammalian brains. The present study identified the presence of cytochrome P450scc in the rat Purkinje cell, a typical cerebellar neuron. Immunohistochemical analysis with the antibody against the purified bovine adrenal P450scc showed an immunoreaction restricted to somata and dendrites of the Purkinje cells in adult cerebella. Preadsorbing the antibody with P450scc resulted in a complete absence of the immunoreaction. The antibody against inositol triphosphate receptor, a marker of the Purkinje cell, recognized P450scc-immunoreactive cerebellar cells that showed no immunoreaction with glial fibrillary acidic protein, a specific marker of glial cells. Expression of the P450scc-like protein in the cerebellum was verified by Western blot analysis, and cerebellar P450scc messenger RNA, by RT-PCR analysis in adulthood. On the other hand, P450scc-immunoreactive cells were found to scatter throughout the cerebellum at 0 day of age, before the differentiation of the first Purkinje cells, while the site of expression of this protein was localized only in somata of Purkinje cells at 3 days of age. Immunoreactive dendrites of the Purkinje cell spread into the molecular layer during neonatal development concurrently with its maturation. The intensity of the immunoreaction did not change during neonatal life. Expression of the cerebellar P450scc messenger RNA was also detected after birth, and the level was almost constant during neonatal life. A specific RIA indicated that the pregnenolone concentration was unexpectedly high at 0 day and decreased until 7 days. The total amount of pregnenolone in the cerebellum was almost constant from 0-7 days and increased during 7-21 days concurrently with the cerebellar development. In contrast, the pregnenolone sulfate ester level was low and did not significantly change among the developmental stages. These results suggest that steroidogenic enzyme P450scc appears in the rat Purkinje cell immediately after its differentiation. The expression of this enzyme may remain during neonatal development and in adulthood.

Downregulation of angiotensin II type 1 receptor gene transcription by nitric oxide

Nitric oxide (NO) plays an important role not only in the regulation of blood vessel tone, but also in the growth of vascular smooth muscle cells (VSMC). The precise mechanism involved in the inhibition of VSMC growth by NO is not known. To further explore the effect of NO on VSMC growth, we examined the effect of NO on the expression of angiotensin II type 1 receptor (AT1-R) that is important for hypertrophy and hyperplasia of VSMC. S-nitroso acetyl DL-penicillamine (SNAP; 200 micromol/L), a potent NO donor, suppressed expression level of AT1-R mRNA by 90% and AT1-R number by 60% after 24 hours of stimulation. The suppressive effect was dose-dependent. Actinomycin D, which is an inhibitor of gene transcription, did not affect the decrease of AT1-R mRNA by NO. Cyclic guanosine monophosphate (cGMP) analogue, 8 bromo-cGMP, did not affect AT1-R mRNA level. Deletion mutants of the promoter region of rat AT1a-R gene were fused to luciferase reporter gene and introduced to VSMC. Transfected cells were stimulated with SNAP, and luciferase activity was measured. Inhibitory effect of NO was still observed in the shortest deletion mutant that contained 61 bp upstream from transcription start site. In this DNA segment, two DNA binding protein were observed by gel mobility shift assay, and one of these binding proteins was decreased on stimulation by NO. NO downregulates AT1-R gene expression independently of cGMP. A DNA binding protein that binds to the proximal promoter region of AT1-R gene may be responsible for this inhibitory effect. The inhibition of AT1-R gene expression may be implicated in the anti-atherogenic property of NO.

Different effects of class Ic and III antiarrhythmic drugs on vagotonic atrial fibrillation in the canine heart

Effects of class Ic drug pilsicainide and class III drug MS-551 were determined in the canine model of atrial fibrillation (AF) induced under vagal stimulation. Pilsicainide injected intravenously at a dose of 1.0 mg/kg over 3 min terminated AF in six of six dogs. After pilsicainide injection, the effective refractory period (ERP) of the right atrium (RA) increased (104 +/- 22 to 122 +/- 31 ms; p < 0.05), and intraatrial conduction time (CT) increased (24%; p < 0.05) in the RA during vagal stimulation. Wavelength index (WLI; ERP/CT), an estimate of the wavelength for reentry, was decreased slightly but significantly (-2%; p < 0.05) in the RA after pilsicainide. MS-551 injected intravenously at a dose of 0.5 mg/kg over a 3-min period terminated AF in three of eight dogs. An additional dose of 0.5 mg/kg of MS-551 terminated AF in three of the remaining five dogs. After MS-551 injection, ERP increased (100 +/- 30 to 143 +/- 28 ms; p < 0.05), but CT remained unchanged in the RA, and therefore WLI was increased significantly (48%; p < 0.01). Immediately before termination of AF with test drugs, mean AF intervals (FF intervals) increased, whereas the standard deviation of FF intervals did not change significantly. In conclusion, both pilsicainide and MS-551 effectively terminated vagotonic AF after an increase in FF intervals. However, changes in WLI were different between the two test drugs. Vagotonic AF could, therefore, be terminated either by prolongation of ERP or suppression of conduction with antiarrhythmic drugs.

The relationship of preoperative magnetic resonance imaging findings and closed system drainage in the recurrence of chronic subdural hematoma

Although chronic subdural hematoma (CSDH) is a well-known entity, its recurrence rate has remained uncertain. There is little knowledge concerning whether the results of radiological imaging can be used to predict CSDH recurrence or whether surgical methods can influence this rate. The first aim of this study is to evaluate the relationship between the recurrence rate of CSDHs and their appearance on preoperative magnetic resonance (MR) or computerized tomography images. The second aim is to evaluate by means of a prospective randomized method the usefulness of closed-system drainage. From January 1988 through June 1996, the authors surgically treated 257 consecutive adult patients with CSDHs. Data obtained in 199 patients who were evaluated preoperatively by MR imaging were analyzed. Thirty-one of these patients underwent bilateral operations and thus 230 operative sites of CSDH were included in the analyses. The cases of CSDH were separated into high- and nonhigh-intensity groups on the basis of the appearance on T1-weighted MR images. From July 1992 to June 1996, the authors conducted a prospective randomized study on the recurrence rate of CSDH in patients undergoing burr-hole irrigation with or without closed system drainage. The recurrence rate of 3.4% in the high-intensity group was significantly lower than the 11.6% rate found in the nonhigh-intensity group (p < 0.05). The recurrence rates following irrigation with and without closed system drainage were significantly different (p < 0.025): 3.1% with closed system drainage and 17% following burr-hole irrigation alone. The surgical procedures were correlated with the MR findings. In the high-intensity group, 1.1% of CSDHs recurred in patients in whom closed system drainage was used and 11.1% in patients without closed system drainage. In the nonhigh-intensity group, 8.1% of CSDHs recurred in patients in whom drainage was used and 23.1% in patients without closed system drainage. Magnetic resonance T1-weighted imaging was useful in predicting the propensity of CSDHs to recur. Closed system drainage significantly reduced the recurrence rate of CSDHs regardless of MR findings.

Chronic angiotensin-converting enzyme inhibition and angiotensin II type 1 receptor blockade: effects on cardiovascular remodeling in rats induced by the long-term blockade of nitric oxide synthesis

We have shown previously that angiotensin-converting enzyme (ACE) inhibitors prevent coronary vascular remodeling (medial thickening and perivascular fibrosis) and myocardial remodeling (fibrosis and hypertrophy) in rats induced by long-term inhibition of nitric oxide (NO) synthesis with oral administration of N omega-nitro-L-arginine methyl ester (L-NAME). ACE inhibitors inhibit both the formation of angiotensin II and the catabolism of bradykinin. In this study, we aimed to determine the relative contribution of the latter two mechanisms to the beneficial effects of an ACE inhibitor on structural remodeling. First, we examined the effects of the ACE inhibitor temocapril and the angiotensin II AT1 subtype receptor antagonist CS-866 on the structural remodeling induced by administering L-NAME for 8 weeks. Temocapril and CS-866 were equally effective in preventing remodeling. Second, we examined whether the effect of temocapril on the remodeling induced by L-NAME was reduced by the bradykinin receptor antagonist HOE140. The latter drug did not alter the beneficial effect of temocapril on remodeling. In conclusion, although species differences must be considered to apply our conclusion to clinical conditions, the present results suggest that the inhibition of angiotensin II activity, mediated via the AT1 receptors, is responsible for the beneficial effects of an ACE inhibitor in our animal model of coronary vascular and myocardial remodeling induced by the long-term inhibition of NO synthesis.

Spontaneous occlusion of a giant basilar tip aneurysm and a basilar artery due to the dissection of both structures: case report

BACKGROUND

Spontaneous occlusion of a giant aneurysm with its parent artery is relatively rare. Complete occlusion of a giant aneurysm at the basilar bifurcation and a basilar artery due to the dissection of the basilar artery has never been reported.

CASE DESCRIPTION

This 62-year-old man presented with left hemiparesis and right oculomotor palsy. Radiographic study showed a giant aneurysm at the basilar artery bifurcation with hemorrhage in its wall and an ischemic area in the right midbrain. Subsequent study revealed that thrombosis of the aneurysm rapidly progressed and that the parent basilar artery caused the dissection. Finally the giant aneurysm and the basilar artery were completely thrombosed.

CONCLUSION

The dissection was considered to occur in the aneurysm wall first by the hemorrhage in it and progress proximally along the basilar artery. Intramural hemorrhage in the wall of a giant aneurysm can be a cause of dissection of its parent artery. This seems to be one of the mechanisms by which a giant aneurysm and its parent artery are spontaneously thrombosed.

Effect of retinol palmitate as a treatment for dry eye: a cytological evaluation

Vitamin A is known to regulate the proliferation and differentiation of corneal epithelial cells and preserved conjunctival goblet cells and has been used in the treatment of disease of the eye such as dry eye and superior limbic keratoconjunctivitis for some time. This study was undertaken in order to evaluate the efficacy of retinol palmitate aqueous ophthalmic solution under development for the treatment of dry eye failing to respond to the conventional therapy with artificial tears or cornea-protective drugs. Retinol palmitate ophthalmic solution was applied repeatedly for 4 consecutive weeks. Before and after instillation therapy, brush cytology (Cytobrush-S) was performed and cytodiagnosis was made for keratinized cells, nonkeratinized cells, goblet cells and inflammatory cells on samples prepared using an automated smear apparatus (ThinPrep). In dry eye, an increase in goblet cells (1.3+/-2.6-->2.1+/-1.8 cells/slides), a decrease in keratinized cells (11.2+/-16.5-->5.2+/-10.9 cells/300 cells) and, hence, an increase in nonkeratinized cells (287.3+/-16.6-->293.4+/-11.4/300 cells) were found after treatment with retinol palmitate. As to inflammatory cells, there was no change from the pretreatment baseline (1.4+/-1.4-->1.4+/-1.3 cells/300 cells). These results demonstrate that brush cytology suggests the efficacy of retinol palmitate ophthalmic solution in dry eye treatment.

Surgical extraction of traumatic orbital mercury

Initial clinical observation of a 2-year-old boy whose right eyelid had been pierced by a glass thermometer 3 days earlier showed a scab-covered cicatrix and slight swelling in the eyelid. X-ray examination showed the broken thermometer tip, fine glass fragments, and mercury droplets beneath the eyelid and extending along the superior orbital margin. On surgical incision, glass fragments and the thermometer tip were found and extracted from the eyelid and orbital fatty tissue with forceps, and 70.3 mg of mercury droplets were readily removed from the same regions by suction via an elastic needle connected to an injection syringe. Blood mercury gradually rose from the normal range to a peak of 28.4 microg/dl 3 months after surgery, then declined during the following 7 months to a level of 15.1 microg/dl. No abnormality has been found in liver or renal function to present.

[Inhibition of experimental autoimmune uveoretinitis by transforming growth factor-beta 1 in B10. A mice]

Experimental autoimmune uveoretinitis (EAU) in mice, an organ specific autoimmune disease, has been investigated as an animal model for human endogenous uveitis. In this study, we report on the immunosuppressive effect of transforming growth factor-beta 1 (TGF-beta 1) on the development of EAU in mice. Inhibition by TGF-beta 1 of proliferation of interphotoreceptor retinoid-binding protein (IRBP)-specific T cell lines in B10.A mice against IRBP antigen was dose-dependent. However, when spleen cells used as the antigen presenting cell were first cultured with TGF-beta 1, this anti-proliferation effect was abolished. When IRBP-immunized mice were injected intraperitoneally with TGF-beta 1, dose-dependent suppression of EAU was obtained. The proliferation response of lymph node cells from TGF-beta 1 injected mice with IRBP-induced EAU was suppressed compared with phosphate buffered saline (PBS)-injected mice. These findings suggest that TGF-beta 1 may be a cytokine that plays a role in suppressing IRBP induced EAU in mice.

A quantitative framework for analyzing epicardial activation patterns during ventricular fibrillation

Few techniques have been developed for deriving quantitative measures of activation patterns during ventricular fibrillation (VF). Such measures have many potential applications, for example, assessing the effects of time, drugs, or electrical interventions. We have developed a new framework for quantifying VF patterns as mapped from an array of approximately 500 unipolar electrodes. Individual activation wavefronts are isolated from one another using an algorithm that groups together adjacent active electrogram samples (dV/dt < -0.5 V/sec). Contacts between wavefronts are detected: these include fractionations, in which a single wavefront breaks into multiple wavefronts, and collisions, in which multiple wavefronts coalesce to form a new wavefront. The timing and contact relationships between wavefronts are summarized as a directed graph. From this model of the VF episode, we derive several parameters: number of wavefronts, number of fractionations, number of collisions, mean wavefront size, mean area swept out, and mean duration. As an example of this analysis, we computed these parameters in six open-chest pigs at 5, 10, 15, and 20 sec after electrical induction of VF. The number of wavefronts and the number of collisions decreased, whereas the mean wavefront size and mean area swept out increased during this period. These results are consistent with previous studies showing a recovery of organization during the first minute of VF.

Histological study of intraocular changes in rabbits after intravitreal gas injection

To study the effects of different intravitreal gases on intraocular tissues, adult pigmented rabbits were given 0.4 mL intravitreal injections of air, 50% sulfur hexafluoride (SF6) and air, 100% SF6, 50% perfluoropropane (C3F8), or 100% C3F8. On postinjection days 1, 4, 7, and 14, the eyes were removed and the iris, ciliary body and retina processed for light and electron microscopy. Histopathological examination found no abnormalities in eyes that received air and none in the irises of gas-injected eyes. Eyes that received 50% or 100% SF6, or 50% C3F8 had vacuolar changes in the ciliary body and retina after maximum gas expansion; these changes were transient, returning to normal as the gas was absorbed. Eyes that received 100% C3F8 suffered irreversible damage to the ciliary body and retina, in both the superior and inferior portions. These observations indicate that expansion of some intravitreal gases can cause both reversible and irreversible changes in intraocular tissues. The degree of damage is affected by the duration of exposure and the gas concentration. Highly concentrated, long-lasting gases can cause irreversible changes resulting in breakdown of the blood-ocular barrier and impaired retinal function.

Occurrence of severe vasospasm following intraventricular hemorrhage from an arteriovenous malformation. Report of two cases

The authors present two rare cases of severe cerebral vasospasm following the rupture of arteriovenous malformations (AVMs). Computerized tomography revealed intracerebral hemorrhage in the thalamus in one case and in the putamen in the other, both accompanied by cast formation of intraventricular clots without radiological evidence of subarachnoid hemorrhage. Initial angiograms showed arterial narrowing of the bilateral internal carotid arteries in the supraclinoid portion but failed to demonstrate an arteriovenous shunt. Subsequent angiograms clearly demonstrated the existence of an AVM. Radiological features and possible mechanisms are discussed.

Recurrent wavefront morphologies: a method for quantifying the complexity of epicardial activation patterns

We have developed a method for quantifying the complexity of activation patterns observed during ventricular fibrillation (VF) that is based on our previously reported methodology for decomposing epicardial mapping data into a set of isolated wavefronts. One-half second datasets are acquired from a 21 x 24 array of unipolar electrodes (1 mm spacing), and the wavefronts are isolated. A correlation technique is used to compute the similarity between all possible pairs of the isolated wavefronts. From these data, the wavefronts are sorted into clusters, each of which represents a recurring wavefront morphology. We define multiplicity (M) as the number of clusters needed to account for 90% of the total activations in the VF episode. M measures the complexity of the rhythm. In repetitive patterns (e.g., sinus rhythm), M = 1, indicating that the same morphology repeatedly activates the mapped region. Typically, in VF, M > 1, with larger numbers representing more complex, disorganized patterns. As an example, we computed M at 5, 10, 15, and 20 sec after electrical induction of VF in six pigs. M decreased significantly (p < 0.001), suggesting increasing organization during this period.

[Three cases of thymic hyperplasia associated with hyperthyroidism]

We encountered three cases of thymic hyperplasia associated with hyperthyroidism. Case 1 was in a 35-year-old woman; a chest CT scan showed an anterior mediastinal mass and right-sided pleural effusion, which suggested the presence of a thymoma Case 2 was in a 21-year-old man who complained of palpebral ptosis and also had myasthenia gravis (Osserman type I). Case 3 was in a 47-year-old woman; a chest CT scan showed thymic hyperplasia and mediastinal lymphadenopathy. In all cases, anti-thyroid medication was given first, because of the associations with hyperthyroidism. Moreover, in cases 1 and 2 no tumor was found, and only hyperplasia was detected in the thymus, although both patients underwent extended thymectomy. Furthermore, surgery was not effective against the hyperthyroidism (anti-thyroid medication could not be withdrawn or reduced). In cases 2 and 3, thymic hyperplasia, as seen on chest CT scans, resolved as thyroid function was normalized by anti-thyroid medication. The pretracheal lymphadenopathy seen in case 3 also resolved. Thymic hyperplasia may have been a result, not a cause, of hyperthyroidism. When we encounter patients with thymic masses and hyperthyroidism, we should give anti-thyroid medication and observe the thymus for some time before resorting to surgery.

[Cervico-omo-brachial pain and disability in a person of advanced age]

A person of advanced age usually has degenerative changes of bone, joint and ligament, which can be causes of cervico-omo-brachial pain and disability. He or she may also suffer from metastatic bone tumor of cervical spine or upper extremity. This article described pathology, signs and symptoms and recent treatment of these diseases. Cervical myelopathy and radiculopathy, which are most common causes of cervico-omo-brachial symptoms, are sometimes accompanied by peripheral entrapment neuropathy such as cubital tunnel syndrome or carpal tunnel syndrome (double crush syndrome). In this complicated situation, decompression of neural tissue in both cervical spine and carpal tunnel are necessary. In treatment for carpal tunnel syndrome, release of transverse carpal ligament under an arthroscope has proven to be useful and has been becoming popular. This minimally invasive surgery is also useful in shoulder surgery such as subacromial decompression in aged patients with rotator cuff tear and removal of calcium deposit in the shoulder joint. Osteoarthritis of the elbow also cause pain or disability of the elbow and the hand. Some metastatic bone tumors are treated by tumor resection and reconstruction with instruments, prosthesis or composite grafts, which are attempted not to cure the disease but to maintain or improve the quality of life of the patient.

The results of transsphenoidal surgery for 44 consecutive acromegalic patients

A series of 44 patients with acromegaly underwent transsphenoidal surgery between 1987 and 1996. The early postoperative mean basal GH level < 5 ng/ml or < 3 ng/ml was achieved in 43 (97.7%) or 38 (86.4%) out of 44 patients, respectively. Preoperative abnormal GH secretory response to TRH, GnRH and oral glucose administration was restored to normal both after surgery and at the time of the final follow-up in all patients whose early postoperative mean basal GH levels were reduced to < 3 ng/ ml, whereas they remained abnormal in those with mean basal GH levels of > or = 3 ng/ml. In contrast, insulin-like growth factor 1 (IGF-1) levels, when measured by the extraction method, tended to be reduced gradually to normal between 6 months and 2 years after surgery in some patients with a successful operation. Therefore, 34 (87.1%) out of 39 patients who have been followed up longer than 6 months met the following stringent criteria at the time of the final follow-up: mean basal GH level < 3 ng/ml, a normal IGF-1 level, and normal GH response to TRH, GnRH and oral glucose administration. In this series, the most unfavorable preoperative factor influencing operative outcome is tumor invasion of the cavernous sinus. Our results clearly indicate that selective adenomectomy by transsphenoidal surgery is the therapy of first choice in any patient with acromegaly and that the complete biochemical cure of acromegaly can be achieved in 87% of patients by surgery alone with an acceptable low surgical morbidity.

Regulation of fibrillar collagen gene expression and protein accumulation in volume-overloaded cardiac hypertrophy

BACKGROUND

Interstitial collagen accumulation has been extensively demonstrated to be increased at both mRNA and protein levels in pressure-overloaded cardiac hypertrophy. However, few data are available regarding the effects of volume overload on myocardial collagens.

METHODS AND RESULTS

To determine whether the alterations of collagens may occur in volume-overloaded cardiac hypertrophy, we measured collagen types I and III mRNA levels and protein accumulation in left ventricular (LV) myocardium of rats at 3, 7, and 28 days after the creation of an aortocaval (AC) shunt. Eccentric LV hypertrophy was produced in rats with AC shunting. Northern blot analysis on RNA extracted from LV tissue indicated that the steady state mRNA levels for both type I and III collagen were persistently upregulated in AC shunt rats compared with sham-operated operated control rats. In contrast, the biochemical collagen protein concentration and morphometric collagen volume fraction were comparable between sham-operated control and AC shunt rats at any study time point. Furthermore, the immunohistochemical staining of types I and III collagen and Sirius red staining on myocardial tissue sections revealed no significant alterations in the distribution or density of fibrillar collagens in AC shunt rats. Tissue collagenase activity was not different between control and AC shunt rats after 28 days.

CONCLUSIONS

Cardiac volume overload increases LV collagen mRNA as does pressure overload. However, in contrast to pressure-overloaded hypertrophy, the upregulation of collagen transcriptional activity does not result in subsequent myocardial fibrosis in volume-overloaded hypertrophy due to AC shunting. Therefore, the upregulation of collagen gene expression and protein accumulation might be different in pressure-overloaded and volume overloaded hypertrophy.

Distal posterior interosseous nerve syndrome

Five patients presenting with chronic dorsal wrist pain and diagnosed as distal posterior interosseous nerve syndrome are reported. Clinical examination revealed point tenderness of the fourth extensor compartment. The symptoms were reproduced by extreme wrist extension in all patients and by extreme flexion in three of the patients. The pain was relieved in all patients by a selective lidocaine block of the terminal branch of the posterior interosseous nerve at the wrist joint. All the patients failed to respond to nonoperative treatment and underwent surgical exploration of the nerve. The operative findings were an enlarged nerve in three patients and adhesion of the nerve to the joint capsule in five patients. A 2 cm section of the nerve proximal to the extensor retinaculum was resected. Four of the five patients had excellent pain relief and returned to full asymptomatic activity. One patient had improvement in pain and was satisfied with the outcome. A diagnosis of distal posterior interosseous nerve syndrome should be considered if the usual sources of dorsal wrist pain are eliminated.

Effects of metrifonate on memory impairment and cholinergic dysfunction in rats

Metrifonate is an organophosphorous compound that has been used in the treatment of schistosomiasis. In this study, we investigated the effects of metrifonate on the impairment of learning and on central cholinergic dysfunction in scopolamine-treated and basal forebrain-lesioned rats. Oral administration of metrifonate (5.0-15.0 mg/kg) ameliorated the scopolamine- and basal forebrain. lesion-induced learning impairment in the water maze and passive avoidance tasks. Metrifonate (50 and 100 mg/kg) also significantly increased extracellular acetylcholine levels but decreased choline levels in the cerebral cortex of the basal forebrain-lesioned rats. The basal forebrain lesion decreased the cholinesterase activity in the cerebral cortex, and metrifonate (100 mg/kg) further reduced the cholinesterase activity. However, cholinesterase inhibition was not observed at the dose that ameliorated learning impairments. These results indicated that metrifonate ameliorated the impairment of learning in both scopolamine-treated and basal forebrain-lesioned rats by not only increasing extracellular acetylcholine levels by inhibiting cholinesterase, but also by undefined other mechanism(s). This finding suggests the usefulness of metrifonate for the therapy of Alzheimer's disease.

Co-secretion of parathyroid hormone and parathyroid-hormone-related protein via a regulated pathway in human parathyroid adenoma cells

Parathyroid-hormone-related protein (PTHrP) is widely expressed not only in malignant tumors but also in both epithelial and nonepithelial cells of normal tissues. Secreted PTHrP is suspected to act as a paracrine or autocrine regulator. However, little is known about its secretory pathway. To cast light on this question, we studied the intracytoplasmic distribution of parathyroid hormone (PTH) and PTHrP immunohistochemically and immunoelectron microscopically in 10 surgically resected parathyroid adenomas. Double immunostaining was performed using anti-PTH antibody and a newly established anti-PTHrP antibody to reveal the relationship between their two distributions. Additional examination by cell immunoblot assay was performed to determine whether both PTH and PTHrP are secreted simultaneously. Both PTH and PTHrP were actually secreted from individual parathyroid cells simultaneously on cell immunoblot assay. Immunohistochemically, there were two different types of adenoma cells, i.e., one positive only for PTH and the other positive for both PTH and PTHrP. PTH was distributed linearly or fine granularly along the cytoplasmic membrane, whereas PTHrP was distributed diffusely or coarse granularly in the cytoplasm. The intracytoplasmic distributions of PTH and PTHrP often overlapped. Immunoelectron microscopical examination demonstrated that PTHrP co-localized with PTH in the same secretory granules. The results clearly demonstrated that PTHrP can be co-secreted with PTH via a regulated pathway using secretory granules.