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Biomedical subjects

F Ichikawa

Publications and source records attributed to F Ichikawa.

At least 37 records · Page 2Linked to original sources
PubMed1994

Dexamethasone enhancement of betaglycan (TGF-beta type III receptor) gene expression in osteoblast-like cells.

Betaglycan (type III transforming growth factor-beta (TGF-beta) receptor) is a cell surface heparan/chondroitin sulfate proteoglycan that binds TGF-beta via its core protein and is abundantly expressed in osteoblastic cells. A previous report (Centrella et al., Mol. Cell. Biol. 11, 4490-4496, 1991) showed post-translational enhancement by glucocorticoid of TGF-beta binding to betaglycan. Upon the availability of the betaglycan cDNA, we investigated the effects of a glucocorticoid analogue, dexamethasone, on the regulation of betaglycan expression in osteoblast-like cells. Betaglycan mRNA was expressed as an approximately 6-kb band in MC3T3-E1 cells. The betaglycan mRNA level was enhanced severalfold by dexamethasone in these cells. The effect of dexamethasone on the betaglycan mRNA level was observed within 9 h and was sustained at least up to 48 h. The dexamethasone effect was dose-dependent, with a saturation concentration at 10(-7) M. Among the steroid hormones examined, dexamethasone exhibited the most potent effect on betaglycan mRNA expression, while retinoic acid also enhanced it moderately. Dexamethasone enhancement of betaglycan mRNA expression was blocked by actinomycin D, but it was not blocked by cycloheximide. Cross-linking experiments showed that dexamethasone treatment increased the binding of radiolabeled TGF-beta 1 to betaglycan, but did not affect binding to the type II receptor. A similar dexamethasone enhancement of betaglycan mRNA expression was also observed in a preosteoblast-like cell line, RCT1. These results suggest that dexamethasone enhances betaglycan expression at least in part via transcriptional events in osteoblasts and this would be one of the target points of glucocorticoid regulation of bone metabolism.

Animals↗
PubMed1994

Anomaly of venous system in congenital occipital dermal sinus.

We report two cases of congenital occipital dermal sinus in which elongation of the vein of Galen, elevation of the straight sinus, division of the superior sagittal sinus, elevation of the confluence of sinuses, elevation of transverse sinus and narrowing of the torcular angle were observed in the venous phase of cerebral angiography. Enhanced computed tomography (CT) revealed enlargement of the supracerebellar cistern, elevation of the straight sinus and of the confluence of sinuses, but no evidence of intracranial lesions. In order to study the relationship between anomalies in the dural venous sinuses and congenital occipital dermal sinus, we examined both cases from an embryological viewpoint.

Arteriovenous Malformations↗
PubMed1992

Possible involvement of leukotrienes in human luteal function.

The present study was undertaken to assess the ability of human corpora lutea to produce leukotriene B4 (LTB4). The maximum capacity of luteal cells to secrete progesterone was attained on day 4, and both the basal production and the responsiveness to hCG decreased thereafter. In contrast, the production of LTB4 by cultured luteal cells was significantly reduced on day 4, but increased thereafter. The basal concentration of LTB4 produced by luteal cells varied from 75 to 590 pg/10(5) cells/2 days. LTB4 production appeared to decrease concomitantly with increased-progesterone production in cultured luteal cells. Exposure to hCG decreased significantly LTB4 production by cultured luteal cells on day 4. An inhibitor of the lipoxygenase pathway, nordihydroguaiaretic acid (NDGA), inhibited LTB4 production in a dose-dependent manner. However, NDGA did not affect basal progesterone production by the cultured luteal cells. A significant inverse relationship existed between the accumulation rates of progesterone and LTB4 in the luteal cells. Furthermore, the addition of LTB4 inhibited progesterone production in a dose-dependent manner in both the presence and absence of hCG. In conclusion, LTB4 could be synthesized by human corpora lutea in vitro, and correlated inversely with the secretion rates of progesterone. These data suggest that LTB4 produced locally in the corpus luteum may be an important regulator in human luteal regression.

Adult↗
PubMed1992

[A case of subarachnoid hemorrhage with sick sinus and advanced AV block].

A 35-year-old man was hospitalized after a sudden onset of transient syncopal attack without accompanying complaints of headache or nausea. He was slightly disorientated but neurologically normal. He had a blood pressure of 150/90mmHg and a pulse rate of 40/min. An ECG showed marked sinus brady-cardia with ventricular escaped rhythm followed by advanced atrioventricular (AV) block. Some components of conducted ventricular beats showed aberration. There was no significant ST or T wave abnormality in normally captured QRS components except for prominent T in leads II, III and aVF. At first, we thought that he might require temporary pacing because of Adams-Stokes attack. However, after administration of atropine sulfate, the ECG returned to normal sinus rhythm with heart rate of 88/min. Then he began to complain of headache followed by a convulsive seizure. A CT scan and angiogram revealed a ruptured aneurysm at the top of the basilar artery, which was successfully clipped. A wide spectrum of ECG changes can be demonstrated in practically all patients with subarachnoid hemorrhage (SAH). Prolonged QT interval, ST-T changes, U wave, sinus tachycardia, or ventricular premature complex are the common abnormalities probably caused by increased circulating catecholamine. As bradyarrhythmia in patients with SAH is an uncommon finding, its mechanism has not yet been defined. Transient sinus bradycardia with advanced AV block in this patient might have been caused not by elevated intracranial pressure (Cushing phenomenon) but by drastic discharge of the parasympathetic nerve. This case serves to illustrate the vigilance required in determining whether abnormalities of cardiac rhythm are instrumental in causing neurological symptoms and signs or a disorder of cerebral function.

Adult↗
PubMed1991

Capsular and thalamic infarction caused by tentorial herniation subsequent to head trauma.

Five patients (4 male and 1 female) were observed to have capsular and thalamic infarction ascribed to descending transtentorial herniation (DTH) caused by head injury. A lucid interval immediately after the trauma and the presence of an epidural hematoma (EDH) characterized all five cases. At the time of hospitalization consciousness was seriously impaired and signs of cerebral herniation were apparent. Two to four days after the trauma, low attenuation in the computed tomography (CT) images pinpointed intracerebral damage in the anterolateral part of the thalamus and in the internal capsule on the same side as that of the EDH in three patients, and in the other two patients bilateral thalamic and capsular damage was noted. The low attenuation implicated the perforating arteries, that is the anterior thalamoperforating and anterior choroidal arteries, suggesting infarcted regions caused by occlusion of these arteries. Findings in the present study suggest that arterial occlusion in closed head injury may result from DTH. Moreover, infarction may be attributed to the delayed effects of injury.

Adult↗
PubMed1990

The effects of lipoxygenase products on progesterone and prostaglandin production by human corpora lutea.

The present study was undertaken to assess the effects of the products of the lipoxygenase pathway on steroidogenesis and the production of prostaglandins (PGs) by human corpora lutea in the midluteal phase. In the first experiment luteal cells were cultured with 5-hydroxyeicosatetraenoic acid (5-HETE) at 10, 100, 500, or 1000 ng/mL in the presence or absence of hCG at 100 ng/mL for 10 days. The addition of 5-HETE dose-dependently inhibited progesterone (P) production by the cultural luteal cells. P production stimulated by exposure to hCG was also reduced significantly in response to 5-HETE. However, 5-HETE had no effect on the production of 6-keto-PGF1 alpha, PGF2 alpha, or PGE2 by cultured luteal cells at any point during the culture period. In the second experiment the reaction products of soybean lipoxidase of arachidonic acid (AA-LIP) were added to cultured luteal cells. Treatment with either AA or LIP alone had no effect on basal P production. The addition of AA-LIP at all concentrations tested reduced P production by cultured luteal cells in the presence or absence of hCG. AA-LIP significantly reduced basal 6-keto-PGF1 alpha secretion in cultured luteal cells on day 2. Although the stimulatory effect of AA on luteal PGE2 production was maintained throughout the entire culture period, the lipoxygenase products of AA did not affect AA-stimulated PGE2 production by cultured luteal cell. These results suggest that the products of the lipoxygenase pathway may be important in the involution of human corpora lutea.

Adult↗
PubMed1990

[A histopathological study on hypoplasia of the enamel].

The research on the development and injury of the hard tissue of teeth was studied by the pedodontic departments of nine dental schools. We participated in this research and studied histopathologically hypoplasia of the enamel in particular. There were seven selected teeth which had obvious hypoplasia of the enamel. We conducted observations with the naked eye, replica, general microscopy, polarized light microscopy, fluorescence microscopy, and microradiography. Moreover we studied to classify these cases into three types, that is to say, the injury factors of whole body, locality, and unknown origin. The results obtained were as follows. 1) As for the injury factors for the whole body, the bottom of the enamel defects were located corresponding to the incremental line of Retzius in the case of enamel hypoplasia of the deciduous teeth. Also enamel hypoplasia was located near the dentino-enamel junction corresponding to the surface of hypoplasia. 2) As for the injury factors with respect to locality, the bottom of enamel defects were located corresponding to the incremental line of Retzius. The dentino-enamel junction was irregular and discontinuous, still more a part of that area, and the dentin protruded or was exposed. 3) As for the injury factors of unknown origin, hypoplasia was located from the surface of the enamel but it did not spread. Also the hypoplasia of the enamel did not correspond to the incremental line of Retzius. 4) Five cases had fluorescence lines in enamel or dentin.

Dental Enamel Hypoplasia↗
PubMed1990

[Effects of 5-hydroxyeicosatetraenoic acid (5-HETE) on progesterone and prostaglandin production by human corpora lutea].

The present study was undertaken to assess the effects of 5-hydroxyeicosatetraenoic acid (5-HETE) on steroidogenesis and prostaglandin (PG) production in cultured luteal cells derived from human corpora lutea in the mid-luteal phase. The luteal cells were cultured with 5-HETE at 10, 100, 500, or 1,000 ng/ml in the absence or presence of hCG at 100 ng/ml for 10 days. The addition of 5-HETE to the culture media did not affect growth curves of cultured luteal cells. 5-HETE significantly inhibited progesterone (P) production by cultured luteal cells in a dose-related fashion on day 2. P production stimulated by exposure to hCG was also reduced significantly in response to 5-HETE. The addition of 5-HETE did not affect estradiol production by cultured luteal cells. The production of 6-keto-PGF1 alpha by cultured luteal cells in the presence of 5-HETE was slightly but not significantly less than that observed in the absence of 5-HETE. However, 5-HETE affects neither PGF2 alpha nor PGE2 production by cultured luteal cells throughout the culture period. The present study demonstrates that 5-HETE inhibits P production in cultured luteal cells by a mechanism(s) other than through PG production. These data suggest the involvement of a lipoxygenase pathway in the synthesis of P and 6-keto-PGF1 alpha of luteal cells.

Adult↗
PubMed1990

[Possible involvement of leukotriene B4 on human luteal function: special reference to determination of leukotriene B4 produced by cultured luteal cells].

The present study was undertaken to determine the production of leukotriene B4 (LTB4) by cultured human luteal cells in the mid-luteal phase using a reverse phase column (C8). The luteal cells were cultured with or without hCG at 100 ng/ml for 8 days. In the preliminary experiment, methods for extracting culture media samples were assessed prior to radioimmunoassay. Reverse phase column C8, but not C18, made possible the determination of LTB4 produced by human luteal cells. Progesterone (P) production by cultured luteal cells reached its maximum on day 4 following exposure to hCG, and then declined gradually. The concentrations of LTB4 produced by luteal cells varied from 100 to 500 pg/10(5) cells/2 days. However, exposure to hCG did not affect LTB4 production by cultured luteal cells. The level of LTB4 in culture medium (115.0 +/- 37.8 pg/10(5) cells/2 days) was reduced on day 4, but increased thereafter. LTB4 production appeared to decrease concomitantly with increased P production of cultured luteal cells. In conclusion, cultured luteal cells produced considerable amounts of LTB4 throughout the entire culture period. These results suggest that lipoxygenase activity of luteal cells may be closely related to steroidogenic potential.

Adult↗
PubMed1989

[Postoperative intracranial pressure in severe cases with hypertensive intracerebral hematoma].

The relationship between the postoperative ICP and the size of hematoma on CT scan and the time of operation was studied to evaluate their influence on the therapeutic results in the severe cases with hypertensive intracerebral hematoma. Twenty one patients of putaminal hemorrhage with severe neurological deficit (semicoma) were studied. ICP was monitored continuously by the Subdural balloon method after craniotomy to remove the hematoma. The relationship between the postoperative ICP level (High ICP: above 40 mmHg, Moderate ICP: 40-20 mmHg, Low ICP: below 20 mmHg), the size of hematoma estimated from CTscan (Large: more than 80 ml, Medium: less than 80 ml), the time from onset to removing hematoma and the therapeutic results were evaluated. The outcome six months after onset was determined according to the Glasgow Outcome Scale. Of 6 cases with Medium hematoma operated on within 8 hours, Low ICP was found in 5 cases (83%) and Moderate ICP was in one case (17%). Of 6 cases with Medium hematoma operated on after 8 hours, High and Moderate ICP were found in 3 cases (50%), respectively. In the cases with Large hematoma, Low ICP was not observed, but High ICP was found in 4 of 7 cases operated on within 8 hours (57.1%) and the other three indicated Moderate ICP (42.9%). High ICP was found in two cases with Large hematoma operated on after 8 hours (100%). The outcome of High ICP cases was severe disability in 4 cases, vegetative state in one and dead in 4, and that of Moderate ICP cases was moderate disability in 3 cases and severe disability in 4.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Role of endosalpinx in the oviductal environment].

The oviducal fluid and serum samples from rabbits were obtained daily during estrus and pseudopregnancy and were analyzed for electrolytes, steroid hormones and prostaglandins (PGs). The oviducal fluid volume reached its maximum (1.72 +/- 0.39 ml/day) 48 hours after hCG exposure and then declined gradually. Although the ratios of Na+/K+ and Ca++/Mg++ in the oviducal fluid did not change substantially throughout the observation period, the levels of K+ in the oviducal fluid were consistently 2.5 times greater than those in the serum. The concentrations of progesterone in the oviducal fluid were significantly smaller than those found in the serum. The levels of estradiol in the oviducal fluid were consistently elevated above the serum levels. The concentrations of PGF2 alpha in the oviducal fluid increased rapidly following ovulation and reached levels that were 10-14 times greater than those found in the estrus, whereas PGF2 alpha levels in the serum did not change significantly during the observation period. A significant difference between PGF2 alpha/PGE2 in the oviducal fluids (3.66 +/- 0.72) and serum (0.25 +/- 0.11) was observed at 24 hours after hCG. A surface morphologic study revealed a decrease in the number of ciliated cells, and an increase and expansion of secretory cells after hCG administration. The qualitative and qualitative differences between the oviducal fluid and serum suggest the involvement of secretory cells in the microenvironment for fertilization and preimplantation embryonic development.

Animals↗
PubMed1989

[Comparative studies on steroidogenesis and prostaglandins production by luteal cells in newly formed corpora lutea and early pregnancy].

The present study was undertaken to assess the ability of cultured luteal cells from human corpora lutea (CL) in the mid luteal phase and the early pregnancy to secrete steroids and prostaglandins (PGs). Luteal cells responded to hCG with a significant increase (2- to 4-fold) in progesterone (P) production. The addition of hCG to the culture media did not stimulate estradiol (E2) production. In contrast, both P and E2 secretion by luteal cells in early pregnancy were significantly lower than those found in the mid luteal phase. Exposure to hCG did not affect P production by luteal cells in early pregnancy. Arachidonic acid (AA) significantly stimulated PGE2 synthesis by luteal cells in the mid luteal phase in a dose-dependent manner. Both basal PGE2 production and the responsiveness to AA were maintained for the duration of the culture. However, hCG did not affect AA-stimulated PGE2 production. Both PGF2 alpha and 6-keto-PGF1 alpha production abruptly declined as the culture proceeded. PG synthesis by cultured luteal cells in early pregnancy was significantly lower than in the mid luteal phase. The ultrastructural characteristics of luteal cells in early pregnancy, which contained lipid droplets, granular and agranular endoplasmic reticulum and large spherical mitochondria, were maintained after 10 days in culture. The present results demonstrate that P and PGE2 production by cultured luteal cells predominate during the mid luteal phase. These data suggest that PGE2, but not PGF2 alpha, may be involved in the regulation of CL function in the menstrual cycle.

6-Ketoprostaglandin F1 alpha↗
PubMed1989

Direct inhibitory ovarian effects of prolactin in the process of ovulation.

The present study was designed to determine the effects of prolactin (PRL) on the process of follicle rupture and oocyte maturation using an in vitro perfused rabbit ovary model. In the first experiment ovaries were perfused for 12 hours with or without PRL at 10(2) or 10(3) ng/ml. Ovulation did not occur in any ovaries in the absence of gonadotropin. The majority of follicular oocytes did not progress beyond the germinal vesicle stage following treatment with PRL. The percentage of follicular oocytes which showed evidence of degeneration was also comparable in both groups. The concentrations of progesterone in the perfusate did not differ significantly between PRL-treated and control ovaries. In the second experiment, ovaries were perfused with or without PRL at 10, 10(2), or 10(3) ng/ml. Thirty minutes later 50 IU of human chorionic gonadotropin (hCG) was added to the perfusate of all ovaries. The addition of PRL to the perfusate inhibited hCG-induced ovulation in a dose-related fashion. The degree of ovum maturity and degeneration was comparable in the two groups. PRL did not affect hCG-stimulated progesterone production by the perfused rabbit ovaries. The present study demonstrates that PRL acts directly on the ovary to influence the process of ovulation, resulting in the inhibition of hCG-induced follicle rupture. These data suggest that PRL inhibits ovulation by mechanism(s) independent of ovarian progesterone synthesis.

Animals↗
PubMed1988

[Basal encephalocele--a report of two cases and consideration of its pathogenetic classification].

The authors have experienced two cases of basal encephalocele without intra and extra cranial anomalies. We have reviewed previous reported cases and studied, from the view point of developmental pathology, reasons why these cases did not have associated anomalies. In this paper we will report our two cases of basal encephalocele and propose a new classification for it, based upon the developmental pathology of the basal part of the skull and associated anomalies. Case 1. A 32 year old male complained of continuous rhinorrhea for 8 months. Coronal CT scan demonstrated a defect of the right sphenoid and ethmoid bone, and a protrusion of isodensity mass, which was enhanced by administration of metrizamide in the subarachnoid space. During the operation, the protruded mass was removed, and the defects of bone and dura mater were repaired. Postoperative course was uneventful. Case 2. A 33 year old male was referred from the department of otology to the department of neurosurgery, because of rhinorrhea and the presence of brain tissue at the time of nasal operation 3 months before. Coronal CT scan revealed a defect of the left ethmoid bone and a protrusion of isodensity mass in it. RI cisternography clearly demonstrated the leakage of CSF through the left nasal cavity. During the operation, the protruded mass was removed and the bone and dura mater defects were repaired. Postoperative course was uneventful. The common findings of both cases are that they were diagnosed by accident in adulthood cases of rhinorrhea, and midsagittal basal bone structure was preserved without extra and intra cranial anomalies.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Effects of experimental salpingoplasty on fertility in the rabbit].

The present study was undertaken to determine the functional capacity of oviduct following distal ampullar salpingostomy and tubal anastomosis. In the first experiment using 6 rabbits, the left fimbria of an oviduct and adjoining ampulla were resected, and then the remaining distal ampulla was subjected to cuff salpingostomy. The contralateral oviduct of each rabbit served as a control. Ovulation was induced at 3 weeks after surgery. The mean number of corpora lutea per ovary in the salpingostomy oviduct (5.00 +/- 0.37) did not differ significantly from that observed in the control oviduct (5.17 +/- 0.31). Five of 6 salpingostomy oviducts contained ovulated ova. However, the retrieval rate was significantly (p less than 0.01) reduced in the salpingostomy oviducts (36.7%), as compared to that found in the control oviducts (93.5%). Scanning electron microscopy of the fimbria revealed morphological features of both ciliated and secretory cells that were comparable to those of the contralateral intact fimbria. The second experiment assessed pregnancy outcome following tubal anastomosis in 6 rabbits. Pregnancy was established in both oviducts of all rabbits. The rate of implantation did not differ significantly between anastomosis sides (75.0 +/- 8.9%) and contralateral controls (93.9 +/- 3.9%). The present data demonstrated that fimbriectomized rabbit oviduct can retrieve ovulated ova, albeit less efficiently than normally. However, information that the retrieval rate of ova after salpingostomy is lower than that found in anastomosis also suggests a significant role of fimbria in ovum retrieval.

Anastomosis, Surgical↗
PubMed1985

[A study on transference of cefminox into intrapelvic tissues].

Intravenous administrations of cefminox (CMNX, MT-141) 1 g as both single shot injection and drip infusion were absorbed rapidly. CMNX showed good transference into intrapelvic organs such as uterus, oviduct and ovary, with the tissue/serum ratios of 37.6% for myometrium, 35.1% for endometrium, 41.4% for cervix uteri, 49.5% for portio vaginalis, 54.3% for ovary and 59.7% for oviduct. From these results, usefulness of CMNX in the field of obstetrics and gynecology was confirmed.

Cephamycins↗