Heterogeneity of the descending thin limb of Henle's loop.
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Animals↗
Biomedical subjects
M Imai
Publications and source records attributed to M Imai.
Trans-complementation of the C gene of human and the P gene of woodchuck hepadnaviruses.
A 5 bp insertion was introduced into the BstEII site at nucleotide 2815 in DNA of hepatitis B virus (HBV) and a mutant HBV genome was produced, which coded for envelope and core proteins, but not for DNA polymerase, due to a frameshift. Cultured hepatoma cells (HepG2) were simultaneously transfected with a plasmid harbouring a tandem dimer of the mutant HBV DNA and another plasmid harbouring a tandem dimer of DNA of woodchuck hepatitis virus or duck hepatitis B virus. The replication of mutant HBV DNA, incapable of encoding DNA polymerase, was accomplished by cotransfecting woodchuck hepatitis virus DNA, but not by duck hepatitis B virus DNA. These results indicated a trans-complementation of the C and P genes in mammalian hepadnaviruses beyond a species barrier.
Animals↗
Production and secretion in Escherichia coli of hepatitis B virus pre-S2 antigen as fusion proteins with beta-lactamase.
The diagnostically important surface antigen pre-S2 of hepatitis B virus was produced in large amounts in the periplasmic space of Escherichia coli. The DNA fragments (pre-S2) coding the pre-S2 antigen were tandemly duplicated or triplicated and ligated in the same reading frame to a fragment containing the promoter and the signal sequence of the alkaline phosphatase-coding gene (phoA) of E. coli. Further, a DNA fragment (bla) coding mature beta-lactamase was joined to the region coding the C terminus of the pre-S2 repeat to stabilize the gene product. Upon induction of the phoA-(pre-S2)3-bla fusion gene, the fusion protein was produced at up to 30% of the total cellular protein. Fractionation of the cellular components and trypsin accessibility of the product showed that the antigen was secreted in the periplasm and formed inclusion bodies there. The signal sequence of alkaline phosphatase was found to be correctly processed in E. coli.
Amino Acid Sequence↗
Effects of PTH, calcitonin, and cAMP on calcium transport in rabbit distal nephron segments.
Distal nephron segments are heterogenous with respect to adenylate cyclase responses to stimulation with parathyroid hormone (PTH) or calcitonin (CT). We examined effects of these hormones and of 8-(p-chlorophenylthio)-adenosine 3',5'-cyclic monophosphate (CPTcAMP) on net Ca absorption (Jnet Ca2+, pmol.min-1.mm-1) in rabbit distal nephron segments by in vitro microperfusion technique. We studied three segments, including distal convoluted tubule (DCT), connecting tubule (CNT), and cortical collecting duct (CCD). PTH (1 nM) in bath significantly increased Jnet Ca2+ from 2.28 +/- 0.35 to 9.44 +/- 1.13 in CNT, but did not affect Jnet Ca2+ in DCT or CCD. CT (1 nM) in bath significantly increased Jnet Ca2+ from 1.58 +/- 0.29 to 4.45 +/- 1.01 in DCT, whereas it did not affect Jnet Ca2+ either in CNT or in CCD. CPTcAMP (30 microM) in bath significantly increased Jnet Ca2+ from 2.29 +/- 0.42 to 3.97 +/- 0.43 in DCT and from 2.43 +/- 0.18 to 5.83 +/- 0.37 in CNT, but it did not affect Jnet Ca2+ in CCD. When Na+ was removed from bathing fluid or when 0.1 mM ouabain was added to bath, Jnet Ca2+ in both DCT and CNT significantly decreased. Furthermore, stimulatory effects of PTH and CT on Ca2+ absorption in the respective segments were abolished under these conditions. These results suggest that PTH and CT increase Ca2+ absorption in CNT and DCT, respectively, through cAMP-mediated mechanisms. Presence of a basolateral Na(+)-Ca2+ exchange process seems to be a prerequisite for effects of these hormones. However, exact intracellular mechanisms remain uncertain.
1-Methyl-3-isobutylxanthine↗
Electrophysiological identification of alpha- and beta-intercalated cells and their distribution along the rabbit distal nephron segments.
By cable analysis and intracellular microelectrode impalement in the in vitro perfused renal tubule, we identified alpha- and beta-intercalated (IC) cells along the rabbit distal nephron segments, including the connecting tubule (CNT), the cortical collecting duct (CCD), and the outer medullary collecting duct in the inner stripe (OMCDi). IC cells were distinguished from collecting duct (CD) cells by a relatively low basolateral membrane potential (VB), a higher fractional apical membrane resistance, and apparent high Cl- conductances of the basolateral membrane. Two functionally different subtypes of IC cells in the CCD were identified based on different responses of VB upon reduction of the perfusate Cl- from 120 to 12 mM: the basolateral membrane of beta-IC cells was hyperpolarized, whereas that of alpha-IC cells was unchanged. This is in accord with the hypothesis that the apical membrane of beta-IC cells contains some Cl(-)-dependent entry processes, possibly a Cl-/HCO3- exchanger. Further characterization of electrical properties of both subtypes of IC cells were performed upon lowering bath or perfusate Cl- from 120 to 12 mM, and raising bath or perfusate K+ from 5 to 50 mM. A 10-fold increase in the perfusate K+ had no effect on VB in both subtypes of IC cells. Upon abrupt changes in Cl- or K+ concentration in the bath, a large or a small depolarization of the basolateral membrane, respectively, was observed in both subtypes of IC cells. The electrical properties of alpha- and beta-IC cells were similar among the distal nephron segments, but their distribution was different: in the CNT, which consists of IC cells and CNT cells, 97.3% (36/37) of IC cells were of the beta type. In the CCD, which consists of IC cells and CD cells, 79.8% (79/99) of IC cells were of the beta-type, whereas in the OMCDi 100% (19/19) were of the alpha type, suggesting that the beta type predominates in the earlier and the alpha type in the later segment.
Animals↗
[On the viscoelastic properties of the palatal mucosa analyzed for the displacement of maxillary complete denture].
The condition of palatal mucosa caused by wearing a maxillary complete denture closely resembles a closed hydrostatic system. To clarify the viscoelastic properties of the palatal mucosa under such a condition, we measured as a function of the degree of denture displacement during biting movements. For this work, we developed three dimensional movement-measuring equipment. The following results were obtained: 1. The displacement of the maxillary complete denture during biting movements (loading and unloading of occlusal forces) could be approximated by an empirical formula of exponential function. This formula expressed the delayed elasticity characteristics of the viscoelasticity of the palatal mucosa. 2. Observation of the denture's displacement revealed that the movement of the palatal mucosa after occlusal forces are unloaded could be regarded as creep according to a Voigtian two-element model. 3. Denture displacement differed between occlusal force loading and unloading: dentures took longer to return to the original position during occlusal force unloading. 4. This time delay, indicating the degree of delayed elasticity of the palatal mucosa, was substantially shorter than the reported value based on local compression tests. Our study clearly shows that when a maxillary complete denture is worn, movement of the palatal mucosa approximates a closed system, and differs from localized open systems.
Biomechanical Phenomena↗
Do the cardiac glands exist? 5. The dog.
The authors performed histological and histochemical investigations on the so-called cardiac glands and gastric glands of the dog, and compared the data on these glands. The conclusions were as follows: 1. The so-called cardiac glands have a number of parietal cells and cells distributed in the same glandular base contain fine pepsinogen granules. However, these glandular cells are filled with a PAS-positive substance. Accordingly, the so-called cardiac glands are nothing but undifferentiated gastric glands. 2. Due to the deep gastric pits, the outer layer of the mucous membrane in the clear zone is loose, and a distribution of a smaller number of blood vessels can be expected. These facts may demonstrate a pale or clear appearance of the mucous membrane in the same zone. 3. The gastric pits in the dark zone are extremely shallow. Accordingly, the mucous membrane in this area is dense and a distribution of a large number of blood vessels can be expected. This probably produces a dark color, i.e., reddish brown. 4. The chief cells in the glandular base of the clear zone contain a number of fine and coarse PAS-positive granules. These granules also are a violet color with PAS-AB (pH 2.5) stain. This color resulted from sialomucin. The above mentioned facts mean that the clear zone is an undifferentiated region of the gastric glands. 5. The chief cells distributed in the glandular body and base of the dark zone are PAS-negative and contain no sialomucin. Accordingly, the same zone is the differentiated region of the gastric glands.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Do the cardiac glands exist? 6. The cat.
We performed histological and histochemical investigations on so-called cardiac glands and gastric glands in the cat to clarify the existence of the former. 1. Cardiac glands possess some parietal cells and strongly PAS-positive glandular cells in the base of glands containing a small number of fine pepsinogen granules. Consequently, we consider them to be undifferentiated gastric glands. Therefore, the cardiac glands do not exist in the cat. 2. Glandular cells in the basal part of undifferentiated gastric glands react negatively or very weakly to AB (pH 2.5 and 0.5) and present a red color with PAS-AB (pH 2.5) stain. 3. A large number of strongly PAS-positive and pepsinogen granule containing cells are distributed not only in the glandular body but also in the basal part of the glands. These cells are immature chief cells. 4. The above-mentioned cells react weakly or moderately to AB (pH 2.5 and 0.5) and stain light purple by PAS-AB (pH 2.5). They possess weak and strong acid mucopolysaccharides and sialomucin. 5. Mature chief cells are distributed mainly in the glandular base. They are PAS-negative, react moderately or strongly to AB (pH 2.5 and 0.5), and present a dark color of AB with PAS-AB (pH 2.5) stain. Consequently, it can be concluded that these cells contain weak and strong acid mucopolysaccharides but no sialomucin. 6. Mature chief cells possess no sialomucin. However, they present stronger reactions to AB (pH 2.5 and 0.5) than those in immature chief cells. This characteristic does not appear in man and many other types of mammals studied.
Animals↗
Fluid-path in the mandible and maxilla.
We examined fluid-paths in the maxilla and mandible of the dog, and compared them with Kihara's extravascular fluid-path-system. Areolar tissue is formed in the walls of the Volkmann's and Haversian canals. This tissue is composed of collagenous and reticular fibers. Kihara confirmed the collagenous fibers were encircled, however we could not ascertain whether they were encircled or not. We have compared the paths in the walls of the Volkmann's and Haversian canals with Kihara's fluid paths, and found the paths in the bone do not belong to the category of Kihara's paths. Namely, the term "extravascular fluid path" should not be applied to the areolar tissue in the bone. We suggest the term "fluid path" for this tissue in the bone. The areolar tissue in the walls of the Volkmann's and Haversian canals and endosteum communicate with one another. We call them collectively endosteum. Yoshikawa called the areolar tissue in the Volkmann's and Haversian canals perivasculäre lymsphräume. However, this designation is inadequate considering the actual characteristics of this tissue.
Animals↗
Comparative histology and histochemistry of the gastric glands of cats and dogs.
We performed histological and histochemical investigations on the gastric glands of cats and dogs. So-called cardiac glands in the cat and dog have a small number of the parietal cells and the PAS-positive glandular cells in the base of these glands contain fine pepsinogen granules. Consequently, we consider them as undifferentiated gastric glands, and can find no differences between these glands in both animals. The immature chief cells in the cat gastric glands are distributed not only in the glandular body but also in the base of the glands and contain sialomucin, and weak and strong acid mucopolysaccharides. The mature chief cells in cat and dog gastric glands contain weak and strong acid mucopolysaccharides. The gastric gland region of the dog is divided into clear and dark zones, and structural differences between the two zones are recognizable. Namely, the chief cells in the glandular base in the clear zone are somewhat undifferentiated, while the chief cells in the middle and lower parts of the glandular body and those in the glandular base in the dark zone are perfectly differentiated. The structure of the gastric glands in the fundic and greater and lesser curvature regions in the cat is very similar.
Animals↗
Do the cardiac glands exist? 7. The cow.
The glands distributed in the narrow region of the abomasum contiguous to the omasum of the cow have been described as cardiac glands. We doubted this assertion and therefore performed histological and histochemical investigations of the glands to clarify their characteristics. 1. All glandular cells except the parietal cells in a few glands contiguous to the omasum react strongly to PAS, AB(pH 2.5), and PAS-AB(pH 2.5) staining, and moderately to AB(pH 0.5) staining. 2. Glandular cells at the base of these glands contain fine pepsinogen granules and a few parietal cells are distributed in these glands, indicating that they are undifferentiated gastric glands and that the so-called cardiac glands do not exist in the cow stomach. 3. Glandular cells in undifferentiated gastric glands are filled with PAS, AB(pH 2.5 and 0.5) and PAS-AB(pH 2.5) positive substances. Which gradually decrease and finally disappear with differentiation, remaining only in the neck (mucous neck cells) and the cells in the upper part of the glandular body (immature chief cells), in mature gastric glands. 4. Mature chief cells in differentiated gastric glands are distributed in the middle and lower bodies and base of the glands and contain a number of PAS and PAS-AB(pH 2.5) positive granules and a large number of coarse pepsinogen granules, while pepsinogen granules in the mucous neck cells and immature chief cells are finer. 5. In the cow the region in which undifferentiated gastric glands are located is very narrow. 6. Parietal cells in the cow stomach are numerous.(ABSTRACT TRUNCATED AT 250 WORDS)
Abomasum↗
[Coats' disease and familial retinal arteriolar tortuosity].
The first Japanese autosomal dominant pedigree of familial retinal arteriolar tortuosity was presented with photographical documentation. The proband, a 7-year-old girl also had typical Coats' disease in her left eye. The fluorescein fundus angiogram revealed retinal telangiectasis and microaneurysms with dye leakage in her left peripheral eyeground and marked arteriolar tortuosity without dye leakage in posterior portions of both eyegrounds. Her father showed prominent retinal arteriolar tortuosity bilaterally, and her sister and paternal grandmother showed mild tortuosity of retinal arterioles in both eyes. The recently proposed hypothesis that the familial retinal arteriolar tortuosity is caused by the retinal microcirculatory disturbance consisting of increased resistance in the retinal capillary bed might explain the coincidental occurrence of retinal arteriolar tortuosity and Coat's disease in this report.
Aneurysm↗
[The precision attachments introduced in Japan].
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Denture Precision Attachment↗
[Pre-treatment of porcelain surface for adhesive restorations].
The effects of pre-treatment of porcelain surfaces, such as etching and treatment with a silane coupling agent, for obtaining firm adhesion between the adhesive resin, Panavia EX, and the porcelain were examined. The effects of heating treatment (100, 150 and 200 degrees C) in applying the silane coupling agents to porcelain surfaces were examined. Infrared spectra and energy dispersive X-ray spectra were obtained for the porcelain surface, on which a silane coupling agent was applied. A stable shearing adhesive strength, such as 450-520 kgf/cm2, was obtained even after a 24-hour immersion in 37 degrees C water, when with the etching the porcelain surface was pretreated with a 30% HF solution (60 sec) or heating treatment (150 degrees C, 10 min) when applying the silane coupling agent (2% gamma-MPTS). Then the adhesive durability was examined by a thermal cycling test (4-60 degrees C, 60 sec). After the thermal cycling test (20,000 times), the adhesive strength to the porcelain surface polished by #600 sand-paper was strong and only when the 2% gamma-MPTS was used did detachment occur. However, the adhesive strength was maintained at about 70-80% of the early strength with the etching treatment by the pre-treatment with 30% HF for 60 sec and the heating treatment (150 degrees C, 10 min) when applying the 2% gamma-MPTS.
Acid Etching, Dental↗
[Mitral valve replacement in 12-month-old infant with parachute mitral valve associated with ventricular and coronary sinus septal defect].
A 12-month-old infant, weighting 6.7 kg, underwent mitral valve replacement with a 17 mm Björk-Shiley prosthetic valve for parachute mitral valve, and patch closure of the associated ventricular and coronary sinus septal defects. Progressive pulmonary artery hypertension and heart failure required surgical intervention. The diagnosis of parachute mitral valve and associated lesions was established by echocardiogram and angiogram. Postoperative recovery was uneventful and he is doing well 3 years after the operation. To our knowledge this is the first successful case to be reported in the literature with such combination of the congenital anomalies.
Age Factors↗
[Successful correction of truncal valve regurgitation and conduit obstruction after previous Rastelli operation for truncus arteriosus (type I)].
A 9-year-old boy had a successful surgical correction of truncal valve regurgitation and obstruction of extracardiac conduit which ensued previous Rastelli operation. He underwent Rastelli operation at the age of 10 months with the diagnosis of truncus arteriosus (Collet & Edwards Type I). At the age of 8 years, he was admitted because of slow weight gain and cardiomegaly (CTR 64%). Cardiac catheterization showed elevated RV pressure, increased pressure gradient across the conduit and severe truncal valve regurgitation. The extracardiac conduit was replaced with a 22 mm Hancock valved conduit and the truncal valve with 23 mm St. Jude Medical aortic valve. Postoperative catheterization revealed a normal RV pressure, only slight pressure gradient across the conduit and no truncal valve regurgitation. He is doing quite well 2 years after the operation.
Blood Vessel Prosthesis↗
[Partial closure of the atrial septal primum defect and biventricular repair for a case of hypoplastic right ventricle with partial atrioventricular canal defect].
An eight-year-old girl with partial atrioventricular canal defect and hypoplastic right ventricle was treated successfully by a palliative open-heart surgery. The preoperative right ventricular pressure was 58/7 mmHg (RVP/LVP = 0.67) and morphology of the right ventricle showed severe tricuspid stenosis and small outflow portion. The preoperative RVEDVI was 31 (41% of normal and tricuspid annulus was 17 mm (47% of normal). The right ventricular outflow was reconstructed with insertion of MVOP and the ASD was partially left open (the amplitude of the interatrial communication was 7 mm). Angiocardiogram two and half years after the operation demonstrated significant right ventricular growth with no right to left shunt through interatrial communication. The RVEDVI was 46 (56% of normal) and tricuspid annulus was 36 mm (90% of normal). This technique can be a procedure of choice in patient with right ventricular hypoplasia, who is not candidate for simple right ventricular reconstruction nor Fontan procedure, as the growth of the right ventricule is expected in the future.
Child↗
[Staged operation for supravalvular aortic stenosis syndrome associated with severe multiple peripheral pulmonary stenoses: a case report and surgical methods].
Successful surgical correction of supravalvular aortic stenosis (SAS) syndrome associated with severe peripheral pulmonary stenosis by a staged approach in a 6-year-old boy is reported. Right ventriculogram demonstrated bilateral severe peripheral pulmonary stenoses and cardiac catheterization revealed severe pressure gradient of 94 mmHg between the trunk of pulmonary artery and right and left peripheral pulmonary arteries, respectively. Bilateral severe peripheral pulmonary stenoses were relieved successfully by staged operations. Initially, a stenotic portion of the right pulmonary artery and its bifurcation was removed and a DeBakey Knitted Dacron graft was interposed between the right pulmonary artery and the peripheral pulmonary artery which was enlarged by arterioplasty. Nine days later, stenosis of the left peripheral pulmonary artery was relieved by arterioplasty using a Rygg patch. Finally, 8 months after the initial operation, the patient underwent definitive repair of SAS by extended aortoplasty. The postoperative course of the patient was uneventful. Our experience indicates that in the surgical treatment of the patient with SAS and associated severe multiple peripheral pulmonary stenoses, a staged approach, that is initial staged repair of the bilateral pulmonary stenoses by arterioplasty through thoracotomy followed by definitive intracardiac repair of SAS, is the procedure of choice.
Aortic Valve Stenosis↗