Biomedical subjects

A Aoki

Publications and source records attributed to A Aoki.

At least 73 records · Page 4Linked to original sources

PubMed1998

Isolation of a frog lectin using polylysine to reduce non-specific interactions with heparin binding ligand.

Polylysine is a polycation used in histology to glue tissue sections to glass slides. It was successfully used to eliminate positively charged proteins from heparin-agarose beds applied for affinity chromatography facilitating the preparative steps in the isolation and purification of heparin binding lectins from the ovary of the frog Leptodactylus occellatus. The addition pretreatment of agarose-heparin beds with polylysine increased more than 3-fold the hemagglutinating capacity of eluted lectin.

Animals↗

PubMed1998

[Urolithiasis associated with Crohn's disease: a case report].

We report a case of urolithiasis caused by surgical treatment for Crohn's disease. A 28-year-old woman was referred to our department for further examination of renal stones from the medical department in September, 1995. She suffered from Crohn's disease and had a history of jejuno-ileal resection because of perforation of the ileum in 1988. Radiographs revealed multiple bilateral renal stones, and the urine oxalate concentration was elevated. She was treated with extracorporeal shock wave lithotripsy and the administration of sodium bicarbonate and citrate, but these treatments did not prevent recurrence and enlargement of stones. Renal function was gradually worsened and we performed transurethral lithotomy and percutaneous nephrolithotripsy. The stones were mainly composed of oxalate calcium monohydrate. A renal biopsy was performed at the operation, showing deposition of crystals in almost all renal tubules. Diet therapy (low oxalate and low fat) and the administration of sodium bicarbonate and citrate were performed strictly and recurrence was not recognized 10 months after complete removal of the stones.

Adult↗

PubMed1998

[Cardiac disorders associated with progressive systemic sclerosis].

This study investigated cardiac disorders in 25 patients with diagnoses of progressive systemic sclerosis based on the criteria of the American College of Rheumatology. All were women, and the mean age was 59 +/- 11 (range 41-80) years old. The duration of the disease was 11 +/- 9 (range 3-40) years. The following complications were seen; Raynaud's phenomenon in all, esophageal disorders in 11, pulmonary fibrosis in 9, diabetes mellitus in 3, high blood pressure in 6, hyperlipidemia in 7, and positive anticardiolipin antibody in 8. Electrocardiography (ECG) and echocardiography were performed to assess the cardiac disorders. Abnormal ECG was seen in 11 patients (44%) and abnormal echocardiograms in 16 patients (64%). ECG abnormalities included incomplete right bundle branch block in 8 (32%), low voltage in 3 (12%), supraventricular arrhythmia in 3 (12%), ventricular arrhythmia in 1 (4%) and septal myocardial infarction pattern in 1 (4%). Echocardiographic abnormalities included valvular diseases in 13 (52%) and pericardial thickening in 7 (28%). No relationship was found between ECG and echocardiographic abnormalities. Echocardiographic abnormalities were more frequently observed in patients with positive anticardiolipin antibody (7/8, 88%) than in those with negative anticardiolipin antibody (9/17, 53%). Especially, pericardial thickening was seen in 63% (5/8) of positive patients, in comparison to 12% (2/17) of the negative patients (p < 0.05). Patients with progressive systemic sclerosis may have several cardiac disorders including conduction disturbances, low voltage ECG, valvular diseases and pericardial thickening. Pericardial thickening has a close relationship with positive anticardiolipin antibody.

Adult↗

PubMed1997

Is warm retrograde blood cardioplegia better than cold for myocardial protection?

BACKGROUND: This study tests the hypothesis that continuous normothermic retrograde blood cardioplegia is superior to cold intermittent blood cardioplegia in protecting the left and right side of the heart transmurally during an extended cross-clamping period. METHODS: Twelve anesthetized, open chest dogs were placed on cardiopulmonary bypass and randomized to receive continuous warm (n = 6) or intermittent cold cardioprotection (n = 6) during a 3-hour aortic cross-clamp period. Transmural left ventricular muscle biopsy specimens were taken before the initiation of cardiopulmonary bypass and 90 and 180 minutes after cross-clamping. Right ventricular (RV) biopsy specimens were taken 180 minutes after aortic cross-clamping. Biopsy specimens were analyzed for adenosine triphosphate, creatine phosphate, and lactate levels and for morphologic changes via electron microscopy. RESULTS: At the end of 180 minutes of cardiopulmonary bypass, the adenosine triphosphate contents of endocardial and epicardial halves of the left ventricular myocardium were only slightly degraded in both cardioplegia groups; a significantly greater reduction in adenosine triphosphate levels occurred in the RV of the warm compared with the cold group (p < 0.02). The difference in creatine phosphate values in the left ventricle between the cold group (35.2 +/- 23.4 nmol/mg cardiac protein) and the warm animals (64.4 +/- 24.9 nmol/mg cardiac protein) was not statistically significant, but the RV creatine phosphate stores were significantly better preserved in the warm compared with the cold cardioplegia group (p < 0.02). Lactate levels increased to a similar extent in both groups, but both values rose significantly over baseline (p < 0.03). Importantly the electron microscopic score of the left ventricle and RV indicated that cells were reversibly and not irreversibly damaged with both cardioplegic protections. CONCLUSIONS: These results suggest the following: (1) Chemical arrest is a major contributor of myocardial preservation during diastolic arrest as used in clinical cardiac surgery. (2) Both methods preserve the ultrastructure of the myocytes transmurally during 3 hours of aortic cross-clamping. (3) Both techniques protect the RV and left ventricle; however, to provide optimal protection of the RV, alternated retrograde and antegrade perfusion might be beneficial over retrograde cardioplegia flow alone, in particular with warm cardioplegia.

Adenosine Triphosphate↗

PubMed1997

Heterogeneity of pituitary lactotrophs: immunocytochemical identification of functional subtypes.

The existence of functional lactotroph subpopulations was confirmed in primary pituitary cell cultures of female rats submitted to estrogen treatment and stimulation with thyrotrophin releasing hormone (TRH) and angiotensin II (A-II). In cell cultures of pituitary tissue, prolactin (PRL) producing cells represent about 50% of the total cell count, most of which (90%) correspond to a typical lactotroph subpopulation characterized by large secretory granules, 500-900 nm in diameter, and well developed rough endoplasmic reticulum (RER) and Golgi complex. Few atypical lactotrophs were detected with a quiescent appearance and containing smaller secretory granules, often indistinguishable from granular content of other pituitary cells. Depletion of endogenous estrogen caused by ovariectomy (OVX) decreased the pituitary lactotroph population about 34%, with a relative increase of atypical forms (56%). Replacement therapy with benzoate estradiol (EB) to OVX rats did not reverse the proportion of typical and atypical lactotrophs gauged in control pituitary glands. The predominant lactotroph population of OVX rat was an atypical PRL producing cell which displayed a quiescent appearance compatible with a reduced secretory activity. By contrast, estrogen administration to OVX rats caused a striking development of the RER, a hypertrophy of the Golgi complex and an increased storage of mature and immature secretory granules in the majority of lactotrophs. These features are compatible with a reactivated protein synthesis. Estrogen also enhanced significantly (p < 0.05) the responsiveness of lactotrophs to A-II and the PRL secretion in both intact and OVX + EB treated rats increased by 40% and 30% respectively. By contrast, A-II did not produce any statistically significant response of lactotrophs from OVX female rats. At variance to this observation, in all models tested TRH increased significantly the PRL secretion (p < 0.05). The correlation of PRL secretion and morphology of different lactotroph subtypes authenticates the existence of a lactotroph subpopulation unresponsive to A-II in pituitary cell cultures from rats depleted of estrogen.

Angiotensin II↗

PubMed1997

Diversity of pituitary cells in primary cell culture. An immunocytochemical study.

In cell cultures of dispersed rat anterior pituitary, the specific identification of each cell type based on their staining properties and the ultrastructural features of secretory granules has proved to be unreliable. The existence of pituitary cell subtypes and the striking remodeling of the cell surface and intracellular organelles, further complicate the specific identification of pituitary cell populations. An immunocytochemical study of dissociated pituitary cells in culture was carried out to identify the cellular hormonal content by applying specific antibodies against prolactin (PRL), and growth (GH), luteinizing (LH beta), adrenocorticotrophic (ACTH) and thyrotrophic (TSH) hormones. Specifically bound IgG was exposed by the electron microscope with protein A-gold complex. Typical lactotrophs, somatotrophs and gonadotrophs are easily recognized because they retain the main features described in the pituitary tissue in situ. Other undefined groups of cells bearing small or medium round secretory granules can be identified by immunocytochemistry as PRL, GH or TSH producing cells. The latter technique was critical for the characterization of the hormonal content of secretory granules, the shape, size, electron density and cytoplasmic distribution of which differ substantially from those described in the intact gland. Cells displaying rare small oval or sharp pointed secretory granules were identified as gonadotrophs with anti-LH beta, while corticotrophs showed granules with irregular profiles not previously reported in the gland. These remarkable morphological changes appear to be related to the interruption of the flow of hypothalamic hormones and the disruption of structural and paracrine interrelationships. This investigation reveals that immunocytochemistry is essential for the specific recognition of the various pituitary cell types, and particularly of atypical cells exhibiting morphological features not found in the pituitary gland in situ.

Adrenocorticotropic Hormone↗

PubMed1997

Different behavior of lactotroph cell subpopulations in response to angiotensin II and thyrotrophin-releasing hormone.

1. In the present investigation we have extended the study of lactotroph subpopulations in primary pituitary cell cultures. Male rats with or without previous estrogenization followed by A-II or TRH treatments were selected as experimental models. 2. The TRH increased up to 50% the PRL released in both whole and OROX+EB rats (P < 0.05). In contrast, A-II treatment introduced no changes in PRL secretion from cell cultures derived from whole male rats but attained a significant augmentation (about 75%) of PRL secreted by ORQX+EB pituitary cells. 3. The addition of TRH and A-II to cultures of ORQX+EB-derived lactotrophs induced cytological changes compatible with a high secretory activity. In estrogen-treated rats the prevailing lactotroph subpopulation is type I. In cell cultures from control and A-II treated whole male pituitaries, the majority of lactotrophs consists of atypical subpopulations of II and III cells, with smaller secretory granules (between 150 and 300 nm in diameter). 4. Morphometry of immunostained lactotrophs performed on light microscopic preparations revealed that about 30-36% of the total cell count were lactotrophs. This percentage was fixed and did not change significantly after TRH and A-II treatments. 5. The present results confirm the presence of morphological and functional subtypes of lactotroph cells in rat pituitary. Typical PRL cell population shows the highest responsiveness to angiotensin II and TRH action. This functional heterogeneity of lactotroph subtypes may reflect an important and scarcely explored factor in the regulatory process of prolactin secretion.

Angiotensin II↗

PubMed1997

Multiple endocrine neoplasia type 1 presented with manic-depressive disorder: a case report with an identified MEN1 gene mutation.

We report a case of multiple endocrine neoplasia type 1 who had repeated hypoglycemic episodes and had previously been diagnosed with bipolar manic-depressive disorder. The patient had a positive family history of multiple endocrine neoplasia type 1 and had multiple pancreatic endocrine tumors, hyperparathyroidism and possibly a pituitary tumor. The pancreatic tumors were resected by subtotal pancreatectomy and examined by histochemical staining and gene analysis. The tumor cells were positive for immunoreactive insulin and glucagon. A microsatellite polymorphism analysis revealed loss of heterozygosity on 11q13 in the tumors. By polymerase chain reaction-based nucleotide sequencing, we identified a germline mutation 483del2 of the MEN1 gene in the normal pancreatic tissue of the patient. This mutation causes a shift of the reading frame of menin mRNA at codon 125. It seems that the wild type allele of the MEN1 gene had been lost in the tumor cells whereas the mutant allele remained intact. This is the first identified MEN1 gene mutation in Japanese families and is different from all MEN1 gene mutations reported previously.

Adult↗

PubMed1997

Germline mutations of the MEN1 gene in Japanese kindred with multiple endocrine neoplasia type 1.

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant familial cancer syndrome. The responsible gene MEN1 has recently been isolated, and its germline mutations have been identified in affected individuals in the United States, Canada and Europe. We screened for MEN1 mutations by direct nucleotide sequencing of all protein-coding regions, and identified five distinct germline mutations in five among six Japanese kindreds with familial MEN1 or familial hyperparathyroidism. The mutations were dispersed across the gene. These findings suggest that, because of the absence of an obvious founder effect, the entire MEN1 gene region should be examined for germline mutations in the probands of MEN1 and related syndromes in Japanese families.

DNA, Neoplasm↗

PubMed1997

Polygalacturonase isolated from the culture of the psychrophilic fungus Sclerotinia borealis.

A polygalacturonase was isolated from the culture medium of Sclerotinia borealis, a psychrophilic fungus that grows on lawn and wheat seedling under the snow in winter and induces the snow mold disease. Pectic acid was a better substrate of this enzyme than pectin when the activity was determined by measuring the reducing sugar produced. However, when the activity was measured by viscosity change, the viscosity of pectin decreased more rapidly than that of pectic acid. The results of viscosity change apparently indicate that the polygalacturonase catalyzes pectin hydrolysis as an endo-type enzyme. Highly methyl-esterified pectin was a poor substrate, as determined by measurements of reducing sugar production and viscosity change. It is suggested from the results that the methoxy group of pectin affects the polygalacturonase reaction. A reaction mechanism was proposed for the polygalacturonase reaction. Molecular mass of this enzyme was 40 kDa and its isoelectric point was pH 7.5. Optimum pH of the enzyme reaction was 4.5 and its optimum temperature was 40-50 degrees C. Thirty percent of the maximum activity was observed at 5 degrees C, but it was only slightly active above 60 degrees C. The activity was preserved for more than 2 years at 5 degrees C and pH 4.5, but it was lost when kept at room temperature overnight or heated at 50 degrees C for 30 min. The amino acid sequence of the N-terminal region of the psychrophilic polygalacturonase of Sclerotinia borealis is compared with those of polygalacturonases of mesophilic fungi. The function of this enzyme against the target plants is discussed with reference to the reaction of polygalacturonases of mesophilic fungi.

Amino Acid Sequence↗

PubMed1997

Lack of association between the Trp64 Arg mutation in the beta 3-adrenergic receptor gene and obesity in Japanese men: a longitudinal analysis.

The beta 3-adrenergic receptor (beta 3AR) is implicated in the regulation of thermogenesis and lipolysis, and it is suggested that the Trp64 Arg mutation in this receptor may contribute to the development of obesity. To examine whether the Trp64 Arg mutation had any effect on body weight during adult life, the beta 3AR genotype was determined in 186 unselected Japanese men, most of whom had records of body weight measured yearly from 25-53 yr of age. Of them, 26 subjects were diagnosed as having noninsulin-dependent diabetes mellitus (NIDDM) and 41 as having impaired glucose tolerance. There were 6 subjects (3%) with homozygous mutation, 67 (36%) with heterozygous mutation, and 113 (61%) with normal allele. Among the 3 genotypes, there were no significant differences in body mass index (BMI) at any age between 25-53 yr and the prevalence of NIDDM at the age of 53 yr. When longitudinal changes in body weight were compared between subjects with and without mutation, the former were less prone to gain weight than the latter. The frequency of the mutant allele was 1) not different among obese (BMI, > 26.4), intermediate (BMI, 22-26.4), and nonobese (BMI, < 22.0) subjects (0.21, 0.22, and 0.26, respectively; P = 0.77); 2) lower in subjects with NIDDM than in those without it, but the difference was insignificant (0.12 vs. 0.23; P = 0.07); and 3) similar between 186 unselected men and another group of 100 patients with NIDDM that were randomly selected for comparison (0.21 vs. 0.23). These results suggest that the beta 3AR is not a major contributing factor to obesity or NIDDM in Japanese men.

Adult↗

PubMed1997

[Cytomegalovirus colitis in a normal woman].

A 32-year-old woman was admitted to our hospital because of diarrhea, fever, and liver dysfunction. IgM antibody to hepatitis C antibody and hepatitis B makers were negative. Antibodies to human deficiency virus was negative. Bacterial cultures of the stool were negative. Sigmoidoscopy on the 9th hospital day showed diffuse edematous and inflated mucosa in the rectum and left-sided colon. Multiple erosions and small ulcers were also present. Polymerase chain reaction examination revealed cytomegalovirus (CMV) DNA in the biopsy specimen of the rectum and the blood on the 10th hospital day. IgG antibody titer to CMV was low, but IgM titer was high. Her physical state had improved and fever resolved without anti-CMV therapy. Second sigmoidoscopy on the 24th hospital day showed normal mucosa. One month later the patient was free from any symptoms. Immunocompromised patients such as recipients of solid organ and bone marrow transplants, patients with AIDS, and patients with malignancies frequently complicate CMV colitis, which can be a major cause of death. Thus, CMV colitis is rarely overlooked in immunocompromised patients. Only a few cases of CMV colitis are reported in adult patients with no risk for CMV infection or associated disease. CMV colitis should be concluded in the differential diagnosis of acute or subacute colitis even in immunocompetent patients.

Adult↗

PubMed1997

Seasonal and experimental reactivation of Leydig cells of the bat Tadarida brasiliensis.

The Leydig cells of the bat Tadarida brasiliensis, exhibit two well-defined periods of secretory activity that are intimately associated to the bat reproductive cycle. During the breeding season (August-September, late Winter and early Spring in the southern hemisphere), the interstitial tissue contains hypertrophic Leydig cells characterized ultrastructurally by the presence of pleomorphic mitochondria, depletion of lipid droplets, proliferation of membranes of agranular endoplasmic reticulum (AER) and enlargement of the Golgi complexes. By contrast, from Spring to Fall concurrent with regression of seminiferous tubules, the Leydig cells acquire a quiescent appearance with reduction in size and volume of AER membranes, atrophy of the Golgi complex and a massive storage of lipid droplets. The changes occurring in Leydig cells during the breeding season can be duplicated experimentally in non-breeding bats with exogenous stimulation with hCG. The gonadotropic treatment induces rapid changes in both interstitial cells and seminiferous tubules. The latter present evident signs of reactivation including proliferation of the spermatogenic cell line, permeation of the tubular lumen and depletion of lipid droplets. The Leydig cells display similar features to those found in the bat during the mating season at the peak of secretory activity. The bat T. brasiliensis is an excellent model to correlate the morphological organization of the Leydig cells with either seasonal fluctuations of its secretory activity or after experimental stimulation with gonadotropins.

Animals↗

PubMed1997

[Transverse submammary skin incision for congenital cardiac surgery].

Submammary skin incision has been accepted as cosmetic approach for open heart surgery. During November 1990 to February 1995, 39 ASD patients under 15 years old were operated with either median or submammary skin incision in Okayama University Medical School. For these patients, retrospective study was carried out to determine whether submammary skin incision made surgical procedure complex and whether patients were satisfied with the scar by submammary skin incision. There were 14 submammary skin incision (Group S) and 25 median skin incision (Group M). There was no significant difference in patients profile between the two groups except for sex. Operative time, cardiopulmonary bypass time and aortic cross clamp time had no significant difference between the two groups. Postoperative ICU stay and hospital stay also did not differed between the two groups. Questionnaires for evaluation of the subjective operation scar was sent with 32 answers (82%). There was no significant difference on questionnaire findings. However for the patients without hypertrophic scar, more patients in Group S were significantly satisfied with their scars. Submammary skin incision was safe and easy. It could be alternative of median skin incision. If hypertrophic scar formation could be prevented, more patients would be satisfied with submammary skin incision than median skin incision.

Cardiac Surgical Procedures↗

PubMed1996

Bactericidal effect of erbium YAG laser on periodontopathic bacteria.

BACKGROUND AND OBJECTIVE: Recently Erbium (Er) YAG laser has been developed for dentistry. It may be suitable for periodontal therapy. This study examined the bactericidal effect of the Er: YAG laser on periodontopathic bacteria in vitro. STUDY DESIGN/MATERIALS AND METHODS: After spreading the bacterial suspension of Porphyromonas gingivalis or Actinobacillus actinomycetemcomitans on agar plates, a single pulse laser was applied to the agar plates at the energy density of 0.04-2.6 J/cm2. The growth of the bacterial colonies on the lased agar plates was examined after anaerobic culture. P. gingivalis colonies were also individually exposed to the single pulse laser at the energy of 1.8-10.6 J/cm2. The colony forming units of the irradiated colonies were counted. RESULTS: Growth inhibitory zones were found at the irradiated sites at the energy of about 0.3 J/cm2 and higher. The survival ratios of the viable bacteria in the lased P. gingivalis colonies decreased significantly at the energy of 7.1 and 10.6 J/cm2, as compared with that of the control. CONCLUSION: These findings suggest that the Er:YAG laser has a high bactericidal potential at a low energy level.

Aggregatibacter actinomycetemcomitans↗

PubMed1996

Urinary type IV collagen as a marker for early diabetic nephropathy.

We investigated the urinary secretion of type IV collagen in 115 subjects with non-insulin-dependent diabetes mellitus (NIDDM) without macroproteinuria, 34 normal healthy subjects and 19 subjects with chronic glomerulonephritis (CGN). We examined the relation between the urinary level of type IV collagen and various clinical parameters. The urinary level of type IV collagen was significantly elevated in NIDDM subjects compared with normal subjects (4.88 +/- 3.12 vs. 1.7 +/- 1.25 micrograms/gCr, P < 0.001). The urinary level of type IV collagen was increased even in NIDDM subjects with normoalbuminuria. The ratio of urinary type IV collagen was significantly lower in subjects with chronic glomerulonephritis (CGN) than those in NIDDM subjects (P < 0.001), although there was no significant difference in the urinary level of type IV collagen between NIDDM and CGN subjects. The ratio of urinary type IV collagen to albumin was under 10.0 x 10(-6) in all subjects with CGN. Our results suggest that measurement of the urinary level of type IV collagen is useful for detection of early diabetic nephropathy and for the differential diagnosis of diabetic nephropathy and chronic glomerulonephritis.

Adult↗

PubMed1996

An alternative pathway for clearance of dead lactotropes from rat pituitary gland.

In the pituitary glands of lactating rats there is a striking proliferation of lactotropes during pregnancy and lactation. After the cessation of lactation, the population of lactotropes experiences an extensive programmed cell death of redundant cells until it reaches prepregnancy levels. The regressive changes occurring in lactotropes are autolytic in nature and usually these cells are engulfed by stellate cells. Other involuting lactotropes are mobilized toward the blood capillaries and some go into the capillary lumen for final disposal, presumably in the mononuclear phagocyte system. In this study we report a sequence of events occurring in regressing lactotropes, investigated by a systematic electron microscope analysis of the rat pituitary gland at different periods after interruption of lactation. Direct disposal of degenerating lactotropes and their cell remnants appears to be an alternative pathway for the clearance of the regressing cells that occur extensively among surplus lactotropes following ablactation.

Animals↗

PubMed1996

Disposal of cell debris from surplus lactotrophs of pituitary gland.

In rats submitted to physiological and experimental stimulation of lactotrophic secretion, as in pregnancy and lactation as well as after estrogen treatment, there is a remarkable proliferation of lactotrophs in the pituitary gland. After interruption of the stimuli, this situation is reversed to basal conditions via a massive programmed cell death of the surplus lactotrophs. The regressive changes occurring in lactotrophs are autolytic in nature, until the advanced stages of degeneration when the cell debris generated by this process are engulfed by phagocytes exhibiting the morphological characteristics of stellate cells. These cells can be seen within the anterior pituitary parenchyma adherent to the wall of capillaries and in the lumen of blood vessels. The number of stellate cells with engulfed lactotroph cell remnants is relatively small in comparison to the massive cell death, an observation that suggests a rapid clearance of cell debris and phagocytic cells from the pituitary parenchyma into the blood stream. The migration of stellate cells from the adenohypophysis involves the degradation of the basement membrane and rearrangement of the capillary wall components. The final disposal of cell debris of regressing lactotrophs within the anterior pituitary therefore appears to be effected by coordination of a pituitary and systemic mononuclear phagocytic system.

Animals↗