Dietary fat and the risk of breast cancer.
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Biomedical subjects
Publications and source records attributed to M Ishikawa.
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The effects of (-)-(R)-2-methyl-3-(1-pyrrolidinyl)-4'- trifluoromethylpropiophenone monohydrochloride (NK433), a novel centrally acting muscle relaxant, on masticatory muscle reflexes were investigated in rats. NK433 inhibited the monosynaptic tonic vibration reflex of the masseter muscle and the polysynaptic tonic periodontal masseteric reflex. These reflexes are increased by gamma-motor activity. NK433 had a weak inhibitory effect on the polysynaptic jaw opening reflex evoked by electrical stimulation of the tooth pulp, which is little related with gamma-motor activity. Eperisone-HCl depressed the three types of masticatory muscle reflexes. When intravenously administered, eperisone-HCl was equipotent to NK433, but the effect of eperisone-HCl was shorter-lasting than that of NK433. The effect of intragastrically administered NK433 on the periodontal masseteric reflex was about three times stronger than that of eperisone-HCl. These results suggest that NK433 inhibits masticatory muscle reflexes controlled by the gamma-motor system and thus may ameliorate the temporomandibular joint syndrome in man.
Cardiotrophin-1 (CT-1) is a novel cytokine that was discovered from mouse embryoid bodies by means of expression cloning. It induces hypertrophy in cultured myocytes by activating a gp130 signaling pathway. To investigate the expression of the CT-1 gene in both normal adult and genetically hypertensive rats, we cloned rat CT-1 cDNA. The amino acid sequence is 94% identical to that of mouse CT-1. A significant amount of CT-1 mRNA was expressed in the ventricle of adult rats and also detected in the lung, kidney, liver, skeletal muscle, stomach and urinary bladder. Northern blot analysis revealed that the CT-1 mRNA level is significantly augmented in the ventricle of 12-week-old spontaneously hypertensive rats-stroke prone/Izm at a stage of established hypertension, suggesting a possible relevance of CT-1 to ventricular hypertrophy.
Erythritol (20 g in solution) was administered orally in a single-dose to 5 patients with diabetes. Serum erythritol levels reached a peak 1 hr after administration and then declined rapidly. Total urinary excretion was 82.0 +/- 3.7% within 24 hr and 88.5 +/- 3.3% within 72 hr. Serum glucose and insulin levels remained unchanged until a meal was taken (3 hr after erythritol administration) and then increased. Free fatty acids and 3-hydroxybutyric acid levels increased after erythritol administration but dropped after ingestion of food. In a separate clinical trial, erythritol (20 g) was administered orally daily for 14 days to 11 patients with diabetes. Mean serum glucose and hemoglobin A1c levels decreased over the time period. Indices of renal function-blood urea nitrogen, creatinine, and beta 2-microglobulin-did not change significantly. The single dose study suggests that erythritol exerts no significant effects on the metabolism of diabetic patients. Two-week daily administration of erythritol had no adverse effect on blood glucose control.
We describe herein the case of a 45-year-old man who developed a periosteal chondroma in a rib at the site of a thoracotomy that had been performed 24 years previously. To our knowledge, this is only the third case of a periosteal chondroma in a rib to be documented in the world literature. Some authors have suggested that trauma, including that of surgery, may induce chondroma formation and this association could have been an important contributing factor in the induction of the tumor in this patient.
In order to identify dipole generators of the N20/P20 and P25, we employed second-order-differentiation in the temporal dimension (temporal-second-order-differentiation; TSOD) with delta t = 2 msec. The rate of variation in the voltage of cortical SEPs calculated by TSOD identified responses of each dipole, reflecting the density of neuronal firing. On topographic analysis, the distributions of N20/P20 and P25 conformed to the shape of gyrus better in the TSOD maps than in the isovoltage maps. The TSOD maps indicated that N20 and P25 were post-central components and that P20 was a pre-central one. Therefore, we concluded that the two dipoles generating N20/P20 and P25 were located in the posterior wall of the central sulcus (area 3b) and the crown (areas 1 and 2) of the post-central gyrus, respectively.
In patients with hemifacial spasm (HFS), the spasm is due to cross-compression of the facial nerve by a blood vessel. There are currently two hypotheses for the mechanism of HFS: 1) the spasm is caused by ephaptic transmission and an increase in excitability at the site of compression; and 2) the spasm is caused by hyperexcitability in the facial nerve nucleus. In peripheral nerves, F-waves, which result from the backfiring of antidromically activated anterior horn cells, have been proposed as indices of proximal motoneuron conduction and anterior horn cell excitability. Enhancement of the F-waves indicates increased anterior horn cell excitability. We have therefore measured F-waves in the facial muscle of HFS patients in order to investigate the excitability of the facial nerve nucleus. The authors obtained facial nerve evoked responses from 20 HFS patients before microvascular decompression (MVD), 10 HFS patients after MVD and 10 healthy controls. The F-waves, obtained with surface electrodes from the mentalis muscle, were the second response after the M-wave. On the patient's spasm side, the F-wave duration, F/M amplitude ratio and frequency of F-wave appearance significantly increased compared with those of the normal side or healthy controls; minimum latency and chronodispersion did not significantly differ between these groups. In patients whose spasm disappeared completely following MVD, the abnormal muscle response (lateral spread), which is a characteristic sign of HFS, and the enhancement of the F-wave eventually also disappeared. Because of the correlation between HFS and F-waves, the authors' study supports the hypothesis that the cause of HFS is hyperexcitability of the facial motonucleus.
PURPOSE AND METHODS: To clarify malignant potential of colorectal sessile adenomas, we investigated 46 colorectal sessile adenomas surgically resected from 44 patients. Lesions were divided into three types according to their macroscopic morphologic features: nodular-type (19 adenomas), villous-type (7), and creeping-type (20). Clinicopathologic features were investigated and compared among these three types. RESULTS: Frequency of focal carcinoma in the nodular-type, villous-type, and creeping-type adenoma was 37, 29, and 55 percent, respectively. Frequency of submucosal invasion in these three types were 11, 14, and 20 percent, respectively. Irrespective of the type, large lesions (> 3 cm) tended to have a higher frequency of submucosal invasion than did smaller ones (60 vs. 20 percent; P = 0.063). Large creeping-type adenomas (> 3 cm) had a definitely higher frequency of submucosal invasion than smaller ones (36 vs. 0 percent; P < 0.05). Lymphatic or vascular invasion of carcinoma was present only in the lesion with submucosal invasion: 5 percent in the nodular-type; 14 percent in the villous-type; 20 percent in the creeping-type. Lymph node metastasis was present only in the creeping-type lesion. CONCLUSIONS: The large creeping-type adenomas (> 3 cm) have a definitely high frequency of submucosal invasive carcinoma. Endoscopic polypectomy or local resection may be adequate for most sessile adenomas. However, we recommend segmental resection of the colon with regional lymph node dissection for a creeping-type adenoma that is larger than 3 cm because of increased risk of submucosal carcinomatous invasion and lymph node involvement.
We identified the sites for the initiation of transcription of a gene for subunit 1 of F1-ATPase (atp1) in rice mitochondrial DNA. Capping and ribonuclease protection experiments in vitro, together with primer extension analysis, demonstrated that there were at least eight transcription initiation sites upstream of atp1. One initiation site, expressed most actively, was flanked by a sequence identical to the consensus promotor motif of rice mitochondrial genes. However, the sequences surrounding the other seven initiation sites exhibited no similarity to the consensus sequence.
Endoscopic ultrasonography (EUS) and magnetic resonance imaging (MRI) are becoming popular methods for examining tumorous lesions along the upper gastrointestinal tract. Though duplication cysts are uncommon, EUS findings from gastric duplication cysts have accumulated and proven very useful for preoperative diagnosis. There have been few reports, however, concerning MRI findings from these cysts. We report herein the case of a 25-year-old man with a gastric duplication cyst. EUS demonstrated a cystic mass adjacent to the fourth layer of the stomach wall. MRI revealed a cyst containing low signal-intensity fluid and high signal-intensity fluid separated by levels. In addition to the characteristic findings from preoperative examinations, the unique histological findings from the cyst are also described.
In patients with hemifacial spasm (HFS) the spasm is due to cross compression of the facial nerve by a blood vessel and microvascular decompression (MVD) has proved to be a successful treatment. Abnormal muscle response (AMR), which can be elicited by one facial nerve branch stimulation in muscles innervated by other branches of the facial nerve, is specific for patients with HFS, and the AMR consists of a constant response occurring about 10 ms after stimulus and an afterdischarge with long duration (variable response, autoexcitation). The F-wave in facial muscles is a small recurrent discharge that antidromically propagates to the facial motonucleus and returns orthodromically down the same axon. We measured the AMRs and F-waves of facial muscles in HFS patients in order to investigate the relationship of both potentials and the origin of the AMRs. We obtained facial nerve evoked electromyograms from 10 HFS patients. The afterdischarges of the AMRs and the enhanced F-waves were always elicited at the same time by marginal mandibular branch stimulation of the facial nerve. There was a linear correlation between the duration of these two potentials in each case. Between the duration of the afterdischarge of the AMRs elicited in the mentalis muscles by the zygomatic branch stimulation of the facial nerve and that of the F-waves in the mentalis muscles, there was also a linear correlation in 10 cases. These results suggest that the F-wave and the afterdischarge have the same origin and that the AMR is an exaggerated F-wave.
The lateral spread (LS) response, which can be elicited in muscles innervated by other branches of the facial nerve, is electromyographycally specific for patients with hemifacial spasm (HFS), occurring about 10 ms after stimulus. The F-wave in facial muscles, which is a late response that antidromicaly propagates to the facial motonucleus and returns orthodromicaly down the same axon, revealed a trend toward enhancement in patients with HFS. The LSs were facilitated by repetitive stimulation during the microvascular decompression (MVD) operation, which has proved to be a successful treatment, and the F-waves were also facilitated by repetitive stimulation on the spasm side more than on the normal side. Greater facilitation of these responses was in direct proportion to higher stimulation rates and greater numbers of stimulations. The repetitive stimulation of the facial nerve may result in activation of the motoneuron pool and in the lowering of the threshold of somatic membranes. These results support the hypothesis that hemifacial spasm is caused by hyperexcitability of the facial motonucleus, which is increased by antidromic repetitive stimulation.
OBJECTIVE: To examine the Rb gene that controls the cell cycle in human endometrial carcinoma. METHODS: Six endometrial carcinoma cell lines (Ishikawa, Hec1-A, Hec1-B, KLE, RL95-2, and AN3 CA) and 48 human endometrial carcinoma tissues were studied by Southern blotting, Northern blotting, polymerase chain reaction (PCR), and DNA sequencing. RESULTS: Southern blotting analysis did not reveal any abnormalities at the DNA level in the endometrial carcinoma cell lines. Size and quantity of Rb transcripts also appeared normal in these cell lines, as evidenced by Northern blotting and reverse transcription-PCR. Sequence analysis of Rb cDNA revealed that the Ishikawa cell line had an abnormality. In human endometrial carcinoma, 20 of 48 cases (42%) were informative and only two cases of 20 (10%) showed loss of heterozygosity at the Rb locus. CONCLUSION: An Rb gene abnormality was found in some human endometrial carcinomas. Therefore, our results suggest that Rb gene abnormalities may be involved in some human endometrial carcinogenesis.
Seven types of ferritinized lectin were used to examine the distribution of glycoconjugates on the outer segment membranes of lamprey photoreceptor cells. Ultrastructural pre-embedding labeling revealed that peanut agglutinin, soybean agglutinin and Ricinus communis agglutinin I were preferentially bound to the proximal, lateral and luminal surfaces of the long cell outer segments, whereas Griffonia simplicifolia agglutinin II and concanavalin A agglutinin were bound to the corresponding surfaces of the short cell outer segments. The results indicate that there is marked difference in the composition of glycoconjugates over the outer segment membranes between long and short photoreceptors.
Strength-duration curves of the ascending and descending conductive spinal cord potentials (SCEPs) in cats were obtained using constant current stimuli. For the formulation of numeric indices of excitability, the rheobase is defined as the minimal current strength below which response cannot occur even if the current continues, and the chronaxie is defined as the minimal duration of a current required to evoke the potential at twice the rheobase strength. The chronaxies and rheobases were calculated from the constructed strength-duration curves. The purpose of this study is to produce strength-duration curves and to evaluate the utility of chronaxies and rheobases for SCEPs. This study showed the following results: (1) there was a hyperbolic relationship between stimulus strength and stimulus duration at threshold values, similar to that seen in peripheral nerves; (2) the ascending and descending tracts of SCEP were mediated through the same pathway (based on the similar chronaxies and rheobases); (3) following spinal cord compression the chronaxie and rheobase increased significantly (P < 0.05), which is similar to peripheral nerve disturbance. However, the rheobase decreased significantly following slight spinal cord compression (P < 0.05) and systemic cooling (P < 0.01), and the strength-duration curve shifted showing a tendency towards decrease of the galvanic threshold, therefore, amplitude augmentation with slight compression and with decrease in temperature seems to contribute to the reduction of the threshold. The strength-duration curve, the chronaxie and the rheobase may be useful in assessing spinal cord function.
We evaluated the effect of endothelin-1 (ET) on the angiotensin converting enzyme (ACE) activity in rat aortic smooth muscle cells (VSMCs). ACE activity was determined by radioimmunoassay of the amount of angiotensin II generated after the addition of angiotensin I (500 pg/ml) to cultured VSMCs. The antibody used had less than 0.1% cross-reactivity with angiotensin I. ACE activity increased 1.9-fold 5 hr after the addition of 10(-6) M ET under serum-free conditions. This stimulatory effect of ET on ACE activity in VSMCs was completely inhibited by 10(-7) M captopril. Results suggested that the ACE present in SMCs is stimulated by ET.