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Biomedical subjects

R Sakakibara

Publications and source records attributed to R Sakakibara.

At least 109 records · Page 6Linked to original sources
PubMed1995

The occurrence of nicked human chorionic gonadotropin (hCG) by a thermolytic endoprotease.

A nicked form of human chorionic gonadotropin (nicked hCG), in which only one peptide bond between residues 47 and 48 (-Gly-Val-) of beta-subunit is cleaved, has been found in the urine and blood of pregnant women. In this study, we investigated the occurrence of nicked hCG and the localization of the nicking enzyme for hCG. First, to determine what type of protease nicks hCG, an in vitro proteolytic study using various proteases was performed. Amino-terminal amino acid sequence analysis of the beta-subunit purified from protease-treated hCG indicated that thermolysin actively nicks hCG. Secondly, to determine which tissues are related to the formation of nicked hCG, the distribution of radioactivity in various tissues after i.v. administration of radiolabeled hCG to female rats was examined. The radioactivity accumulated predominantly in the kidney (17%), liver (9.3%) and ovary (0.9%) after 30 min of injection. Analysis of molecular species of beta-radiolabeled hCG in various tissues and body fluids, using sodium dodecyl sulfate polyacrylamide gel electrophoresis followed by autoradiography, indicated that a nicked hCG-like molecule was found in the kidney, predominantly, as well as in the serum and urine. To examine the role of the kidney in producing nicked hCG, hCG was incubated with rat kidney particulate fraction (KPF). Immunoblot analysis of KPF-treated hCG indicated that KPF produced a nicked hCG-like molecule. Furthermore, the possibility that placental trophoblast cells produce nicked hCG was also examined using the choriocarcinoma cell BeWo.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1994

Effects of beta 2-stimulants on contractility and fatigue of canine urethral sphincter.

The effects of beta 2-stimulants [clenbuterol (CB) and terbutaline (TB)] on the contractility of the urethral sphincter of female dogs were studied by measuring intraurethral pressure (IUP) during stimulation of bilateral pudendal nerves. In nine dogs 1, 10 and 100 micrograms/kg. of CB were administered, but no changes in IUP were observed. In the other 33 dogs, sphincteric fatigue was experimentally prepared by electrically stimulating the pudendal nerves at 15 V, 20 Hz for 30 to 40 minutes. In fatigued sphincters, CB (n = 17) and TB (n = 7) increased the contracting pressure (pressure difference between stimulation-generated peak level and baseline level of IUP). The inotropic effect of beta 2-stimulant (TB) on the fatigued urethral sphincter was abolished by a beta-blocker, propranolol. From the present study it was concluded that beta 2-stimulants have little effect on the total contractility of the nonfatigued urethral sphincter because it is composed of smooth and striated muscles (fast- and slow-contracting muscles). However, beta 2-stimulants enhanced the contractility of fatigued urethral sphincter. These results suggest that beta 2-stimulants act on fast-contracting fibers in the urethral sphincter because the inotropic effect of sympathomimetic amine is much greater on fatigued, fast-contracting fibers than on nonfatigued ones and its depressive effect on slow-contracting fibers is not potentiated after fatigue.

Animals↗
PubMed1994

Improvement of urethral resistance after the administration of an alpha-adrenoceptor blocking agent, urapidil, for neuropathic voiding dysfunction.

We assessed the effect of a new alpha-blocking agent, urapidil, on neuropathic voiding dysfunction, by urodynamic studies. The residual urine volume and rate significantly decreased, whereas the average and the maximum flow rate did not increase significantly. The pressure at maximum flow and minimum urethral resistance decreased significantly. These results suggest that improvement of the voiding dysfunction in some cases could be due to the decreased micturition pressure without increasing the flow rate. The urethral resistance calculated from the pressure/flow data seemed to be a valuable index in evaluating the effects of the drug on neuropathic voiding dysfunction.

Adrenergic alpha-Antagonists↗
PubMed1994

Antibody against a peptide corresponding to the extracellular domain of the luteinizing hormone/chorionic gonadotropin receptor stimulates testosterone production in rat Leydig cells.

In order to study the function of LH/CG receptor, we prepared four synthetic peptides (RP1, 2, 3, and 4 for residues 242-255, 49-66, 493-504, and 573-584) corresponding to extracellular domains of rat ovary LH/CG receptor and raised antibodies against RP1 and RP2 (anti-receptor peptide IgGs). These peptides and IgGs were assayed for inhibition of 125I-labeled hCG binding to Leydig cell membrane receptors. However, neither the peptides nor the IgGs inhibited hCG binding to the receptor at doses up to 10(-3) and 10(-5) M, respectively. On the other hand, although anti-receptor peptide IgGs did not show inhibition of hCG binding to the receptor, it was found that one of the IgGs (anti-RP1IgG) was bound to the cell membrane and stimulated testosterone production in rat Leydig cells. F(ab')2 fragment lacking the N-linked sugar chain in the IgG molecule, whose sugar chains are similar to those of hCG, was prepared from anti-RP1IgG. Anti-RP1F(ab')2 was still bound to the cell membrane but no longer stimulated testosterone production. These results suggested that when LH/CG receptor binds to a glycoprotein, even if it is different from the native ligand hCG, it may interact with sugar chains of the glycoprotein to cause signal transduction. Thus, a lectin-like domain in or near the receptor may play a key role in the receptor function.

Amino Acid Sequence↗
PubMed1994

Micturitional disturbance in human T-lymphotropic virus type-1-associated myelopathy.

We reported the findings of micturitional histories and urodynamic studies in five patients with human T-lymphotropic virus type-1-associated myelopathy. Histories showed that all patients had obstructive as well as irritative micturitional symptoms, and four of their micturitional symptoms appeared from the onset of the disease. Urodynamic studies showed that four of them had residual urine (average 170 ml), all had detrusor hyperreflexia, two had detrusor-sphincter dyssynergia, and none had neurogenic changes in external urethral sphincter electromyography. Our findings of supranuclear type of voiding dysfunctions seemed to be in accordance with the known pathological lesions of this disease.

Adult↗
PubMed1993

Significance of the amino terminus of rat testis fructose-6-phosphate, 2-kinase:fructose-2,6-bisphosphatase.

In order to assess the functional properties of the extreme amino-terminal peptide of rat testis fructose-6-phosphate,2-kinase: fructose-2,6-bisphosphatase, 24 and 30 amino acids from the NH2 terminus were deleted using oligonucleotide-directed mutagenesis. The expressed wild-type (WT) and the mutant (Del 24 and Del 30) enzymes were purified to homogeneity. These enzymes were homodimers of subunit M(r) values 54,000, 51,300, and 50,600. Deletion of 1-24 and 1-30 residues resulted in over 70% loss of Fru-6-P,2-kinase activity and 2-fold increase in Fru-2,6-bisphosphatase. KmFru-6-P increased 7.5-fold, but there was no significant change in KmFru-2,6P2 of the phosphatase. These mutant enzymes were more susceptible to protein concentration-dependent dissociation and thermal inactivation. In 2 M urea the kinase and the phosphatase activities of WT increased 17 and 56%, respectively, but no activation of any of the mutant enzymes was observed. At higher urea concentrations, all the enzymes were inactivated. Unfolding in urea, followed with intrinsic tryptophan fluorescence, showed that the unfolding proceeded in at least two stages. Fluorescence intensity at 338 nm of all these enzymes decreased below 2 M urea in which the enzyme activities remained the same (Del 24) or activated (WT). The second stage of unfolding was seen as the maximum shifted to 342 nm in 2-4 M urea, presumably involving dissociation. Complete unfolding above 4 M urea resulted in further shift in fluorescence maximum to 350 nm.

Amino Acid Sequence↗
PubMed1993

Factor in urinary extracts from pregnant women that inhibit mouse oocyte maturation in vitro.

Mouse oocyte maturation inhibitory factors, on the basis of inhibitory activity of spontaneous germinal vesicle breakdown (GVBD) of denuded mouse oocytes in culture, were extracted and partially purified by reversed-phase resin adsorption and Sephadex G-100 and G-50 column chromatographies from the urine of pregnant women. Denuded oocytes obtained from ovaries of ICR mice underwent spontaneous GVBD by cultivation for 3 h in modified Krebs-Ringer's buffered solution, while this spontaneous GVBD was found to be inhibited by adding the final preparation (U-D-4) of urine. The inhibition was dose dependent, ranging from 0.6 to 10 micrograms protein/ml medium. Oocytes treated with U-D-4 and resuspended in control medium resumed GVBD. The molecular mass of U-D-4 was estimated to be less than 2,000 Da with gel filtration. Ether treatment failed to extract inhibitory factor(s) from U-D-4 and pepsin treatment inactivated U-D-4, indicating that inhibitory factor(s) in U-D-4 are peptide-like substances. The inhibitory effect of U-D-4 on spontaneous GVBD was partially reversed in the presence of naloxone, a potent opioid antagonist. U-D-4s obtained from urine samples of pregnant women, nonpregnant women, and men showed the inhibitory effect on spontaneous GVBD; however, the activity of U-D-4 obtained from pregnancy urine was significantly more potent than those of the other urine samples.

Animals↗
PubMed1993

Micturitional disturbance in progressive supranuclear palsy.

Detailed micturitional histories were taken from nine patients with progressive supranuclear palsy (PSP), and eight of them (89%) had micturitional symptoms including urinary incontinence in seven. Urodynamic studies were performed in six patients and the results were as follows. Three had residual urine of 100 ml on average. Four had detrusor hyperreflexia and one had a low compliance cystometrogram. One had detrusor-sphincter dyssynergia. Motor unit analysis of external sphincter was performed in four patients and two had neurogenic changes. The results were compared with our previous findings in Parkinson's disease and in striato-nigral degeneration (SND), and we found that a severe degree of micturitional disturbance in PSP seems to be as common as in SND, especially in the urinary storage phase, and more frequent than in Parkinson's disease. Supranuclear types of pelvic and pudendal nerve dysfunctions seemed to be mainly responsible for micturitional disturbance in PSP.

Aged↗
PubMed1993

Lower urinary tract dysfunction in the anterior spinal artery syndrome.

Lower urinary tract function was studied in 10 patients with the anterior spinal artery syndrome. In the acute stage all patients had complete urinary retention. Cystometry in 3 patients showed detrusor areflexia. At a neurologically stable stage 9 patients could void and 1 had urinary retention during the preceding 7 years. Cystometric bladder capacities at first and maximum desire to void were decreased in 8 patients and normal in 2. Detrusor hyperreflexia was noted in 8 patients, a normal bladder in 1 and detrusor areflexia in 1. External urethral sphincter electromyography revealed detrusor-sphincter dyssynergia in 4 patients and normal findings in 6. We conclude that the vesicomotor dysfunction in this syndrome is similar to that of traumatic spinal cord injury except that bladder sensation is preserved. The latter finding indicates that at least some of the bladder sensation travels via the posterior columns of the spinal cord.

Electromyography↗
PubMed1993

Immature human chorionic gonadotropin (hCG) in first trimester placental cells is bound to an ATP-binding protein forming high-molecular-weight hCG.

Human chorionic gonadotropin (hCG) in first trimester placental cells is made up of immature alpha- and beta-subunits containing only N-linked high-mannose sugar chains, which are of 21 kDa for the alpha-subunit and 23 and 19 kDa for the beta-subunit. However, the apparent molecular weight of immature hCG from placental cell extracts has been estimated from gel filtration to be much higher (100-200 kDa; high molecular weight-hCG, HMW-hCG) based on gel filtration than the theoretical value (approximately 44 kDa) of the alpha beta dimer (alpha beta-hCG). We prepared a gel-filtered fraction containing HMW-hCG and investigated treatments for converting it to alpha beta-hCG. We found that the molecular weight of HMW-hCG was decreased to close to that of alpha beta-hCG by treatment with acetone, proteases, or chelating agents. These treatments also shifted the isoelectric point of HMW-hCG from the acidic region (pI = 4-6) to the alkaline (pI = 9-11), approximating to that of alpha beta-hCG. We also found that HMW-hCG, but not acetone-treated HMW-hCG, bound to ATP-agarose resin. These results suggested that the immature alpha beta-hCG molecule in placental cells may be bound to an acidic ATP-binding protein to form HMW-hCG.

Acetone↗
PubMed1993

Micturitional disturbance in radiation myelopathy.

Detailed micturitional histories and urodynamic studies were performed in five patients with radiation myelopathy. All patients had micturitional symptoms that were irritative in five and obstructive in four, and four had urinary incontinence. Urodynamic studies showed that three patients had residual urine of 158 ml on average. Cystometry showed that four patients had detrusor hyperreflexia and one had low compliance cystometrogram. External sphincter electromyography showed that four patients had detrusor-sphincter dyssynergia. These results indicated that micturitional disturbance seemed to be common and severe in storage as well as evacuation function. The main responsible sites of lesions seemed to be supranuclear parasympathetic and somatic nervous systems regulating the lower urinary tract. Two of three patients who underwent combination of steroid pulse therapy and hyperbaric oxygen therapy experienced improvement of micturitional disturbance and other neurological deficits.

Adrenal Cortex Hormones↗
PubMed1993

Micturitional disturbance in multiple system atrophy.

Detailed micturitional histories and urodynamic studies were conducted to investigate the micturitional disturbance in multiple system atrophy (MSA). Eighty-six patients with MSA comprised of 14 with striatonigral degeneration (SND), 42 with olivopontocerebellar atrophy (OPCA) and 30 with Shy-Drager syndrome (SDS). The results were as follows. Micturitional symptoms were noted in over 90% of patients with each type of MSA. Dominant symptoms were irritative ones in SND and OPCA, and a combination of irritative and obstructive ones in SDS. Micturitional symptoms in SDS appeared earlier than those in SND or OPCA. The degree of micturitional disturbance was severer in SDS than in SND or OPCA. Micturitional disturbance tended to become worse as the disease progressed. The responsible sites of lesions of micturitional disturbance seemed to be supra- as well as infranuclear lesions of the pelvic and pudendal nerves in MSA. Infranuclear lesions were more prominent in SDS than in SND or OPCA. Follow-up studies of some of the patients with SDS and OPCA suggested that the responsible sites of pelvic nerve lesions changed from supra- to infranuclear lesions during the course of disease.

Autonomic Nervous System↗
PubMed1993

[Paramedian dorsal syndrome of mesencephalic tegmentum].

Two cases of brainstem infarction involving a unilateral side of the midbrain tegmentum showed a peculiar ocular symptom complex. The ocular syndrome consisted of (1) oculomotor palsy ipsilateral to the lesion, (2) monocular eyelid retraction and upward gaze palsy contralateral to the lesion, and (3) conjugate downward gaze and convergence palsy. By computed tomography and cerebral angiography, the lesion shared by the two cases was identified in the territory of median mesencephalic rami originating from the posterior cerebral artery. The lesion involved oculomotor nucleus on a side. Contralateral monocular symptoms and conjugate palsies could be attributed to a damage in their supranuclear tracts. Considering with two similar cases in the literature, it is strongly suggested that a unilateral ischemic lesion of the paramedian dorsal part of the midbrain tegmentum is responsible for this syndrome. Bilateral or unilateral eyelid retraction (Collier's sign) was considered to locate a lesion in the posterior commisure by Collier himself. The posterior commisure is, however, not involved in our two cases, and a paramedian lesion of the midbrain tegmentum deviated to a side may cause contralateral eyelid retraction. A combination of ophthalmoplegia ipsilateral to the lesion, upward or lateral (in the opposite direction to the lesion) gaze palsy, and hemiataxia on the contralateral side resembling our second case is sometimes erroneously called Nothnagel's syndrome. Nothnagel mentioned symptomatology of the quadrigeminal bodies for local diagnosis in his text in which he did not describe this combination of signs.

Cerebral Infarction↗
PubMed1993

[Alloesthesia without impairment of consciousness after right putaminal small hemorrhage].

Alloesthesia is a condition in which a sensory stimulus, given on one side of the body, is perceived to be at the corresponding area on the opposite side. In our previous study (Kawamura, Hirayama et al., 1987), we suggested that it may be useful for localization because this phenomenon was observed most frequently in patients with a right putaminal hemorrhage of medium or large size, an average of 42 ml on CT scans, presenting a slight disturbance of consciousness and, in about half of the patients, anosognosia. We also suggested that since alloesthesia is produced not only in cerebral but also in spinal cord lesions, it seems to represent an elementary sensory disturbance of sensory pathways, not a higher cortical dysfunction. We recently observed alloesthesia in two other patients with smaller right putaminal hemorrhages, 7 ml and 6 ml, respectively, who exhibited no disturbance of consciousness, but had impairment not only of superficial but also of proprioceptive sensations. In Patient 1, superficial sensations were intact on admission, except those on the left side of the face. Cortical somatosensory evoked potentials (SEPs) after stimulating the median nerve were measured on Patient 1 on the 11th hospital day when a left hemihypalgesia had developed due to enlargement of the hematoma from 7 to 14 ml. Stimulation of the clinically affected side (left) evoked no N20 from the contralateral scalp. Right-sided stimulation was normal. The fact that both patients showed alloesthesia with no accompanying disturbance of consciousness supported our view of its mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Periodic alternating nystagmus in familial congenital cerebellar ataxia].

We noted periodic alternating nystagmus (PAN) in two patients (mother and daughter) who were diagnosed as familial congenital cerebellar ataxia. The mother was 51-year-old and her PAN had about 4 minutes cycle. During eye closure there was a deviation of arms and trunk parallel to the direction of the slow phase of nystagmus. Vestibular stimulation during rotatory and caloric tests disclosed enhanced vestibulo-ocular reflexes, changes of direction and prolonged cycle of PAN. The patient had no visual suppression during caloric stimulation. The daughter was 14-year-old and although she had no spontaneous PAN she had latent PAN by showing changes of direction of nystagmus during the caloric stimulation. She had also no visual suppression during caloric stimulation. From these results the mechanism of PAN could be attributed to the periodic hyperfunction of vestibular nuclei caused by reduced suppression from cerebellar uvula and nodulus.

Adolescent↗
PubMed1992

Characterization of a unique nonsecretory ribonuclease from urine of pregnant women.

We have reported previously [Sakakibara, et al. (1991) Chem. Pharm. Bull. 39, 146-149] that a protein purified from a partially purified pharmaceutical preparation of human chorionic gonadotropin (a urinary protein preparation from pregnant women) is a unique nonsecretory ribonuclease (RNase)-like protein on the basis of its amino terminal sequence homology. We purified the protein further from the same materials by gel filtration and reversed-phase column chromatographies with RNase activity as an index. The purified protein was designated RNase UpI-2. The catalytic activity and its sensitivity to inhibition by divalent cations suggest that the protein is related to nonsecretory RNase. The estimated molecular weight of RNase UpI-2 (38 kDa) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was significantly higher than that of urinary nonsecretory RNases (13 to 19 kDa) reported so far. After trifluoromethanesulfonic acid treatment, the molecular weight of RNase UpI-2 was reduced and approached that of nonsecretory RNase, which indicated that the protein contains a significant amount of carbohydrate (approximately 50%). RNase UpI-2 was immunoreactive with antibodies to a nonsecretory RNase, RNAase 1 [Yasuda et al. (1988) Biochim. Biophys. Acta 965, 185-194]. By immunoblot analysis of the protein freshly prepared from various urine samples, it was shown that a considerable amount of RNase UpI-2 is present in urine of pregnant women, but only a trace of RNase UpI-2, if any, was detected in urine of nonpregnant women and men. These results suggest the possibility that RNase UpI-2 may have been formed via a specific protein modification in pregnant women.

Amino Acid Sequence↗
PubMed1992

Micturitional disturbance in tumors of the lumbosacral area.

Neurourological studies were performed on 15 patients with tumors at or below the first lumbar vertebra. Micturitional history revealed that 14 patients (93%) had voiding symptoms. Four patients had incontinence and three had urinary retention. Urodynamic studies revealed that three of six patients tested had abnormal uroflowmetrograms. Urinary residuals greater than 100 ml were observed in 6 of 12 patients. Detrusor hyperreflexia occurred in 3 of 15 patients, 4 of 15 had low-compliance detrusor, and 2 of 15 had detrusor-sphincter dyssynergia. There were no differences in lower-extremity neurological signs in patients with or without incontinence, and patients with or without large residual urine and urinary retention.

Adolescent↗