Partial purification and characterization of sphingosine N-acyltransferase (ceramide synthase) from bovine liver mitochondrion-rich fraction

Sphingosine N-acyltransferase (ceramide synthase, E.C. 2.3.1.24) was solubilized from bovine liver mitochondrion-rich fraction with n-octyl beta-D-thioglucoside as the detergent and partially purified by sequential chromatography on columns of DE-32, shingosine affinity, and Sepharose CL-6B. The partially purified preparation migrated on SDS-polyacrylamide gel electrophoresis as two major protein bands of 62 and 72 kDa. The molecular mass of the enzyme estimated by gel filtration was 240-260 kDa, suggesting that the partially purified enzyme is present in a subunit form or simply has an aggregative nature. The specific activity of the final preparation for the condensation of sphingosine with stearoyl-CoA increased by 98.7-fold compared with the starting material. The optimal pH value for the ceramide synthesis was 7.5. The partially purified enzyme had an apparent Km of 146 microM and a Vmax of 11.1 nmol/min/mg protein for stearoyl-CoA. The Km and Vmax values toward sphingosine were 171 microM and 11.3 nmol/min/mg protein, respectively. Interestingly, sphinganine was also a good substrate for this enzyme, and the Km and Vmax values were 144 microM and 8.5 nmol/min/mg protein, respectively.

Undifferentiated carcinoma of the liver with neuroendocrine features: a case report

Undifferentiated carcinoma of the liver is very rare. A 54-year-old man was admitted to our hospital for a detailed examination of multiple liver tumors. These tumors were high or low echoic on ultrasonography, but not enhanced by contrast medium in dynamic computed tomography. A fine-needle aspiration biopsy specimen of the tumor showed undifferentiated carcinoma. The serum level of neuron-specific enolase was high (357 ng/ml) and the immunohistochemical stain of the biopsy specimen was positive for synaptophysin. We diagnosed the patient as having undifferentiated carcinoma of the liver with neuroendocrine features. The patient was treated with combined systemic chemotherapy: etoposide 100 mg/m2/day for three days plus cisplatin 80 mg/m2/day on day one. He achieved a partial response, the duration of which was 7+ months. The serum neuron-specific enolase levels were decreased to the normal range after chemotherapy. Primary liver carcinoma with neuroendocrine features is extremely rare, but in a suspicious case it is important to measure the serum levels of neuroendocrine markers and make a histological confirmation, because chemotherapy may be effective for this disease.

[A case of AIDS complicated with isosporiosis as initial manifestation]

We reported a Thailander patient with isosporiasis accompanied by AIDS. The 34-year-old male, who had been living in Japan for six years, was admitted to our hospital complaining of diarrhea and body weight loss. After admission the patient developed acute renal failure due to dehydration resulting from diarrhea. Laboratory findings on admission showed neither significant microorganisms nor parasite ova in the stool. The patients was given both an intestinal drug and an antibacterial agent, but is vain. Frequent stool examinations disclosed Isospora oocyst in the feaces. Co-trimoxazole was administered resulting in remarkable diarrheal improvement. Renal function was also improved without dialysis. Although isosporiasis is rarely found in Japan, it is stressed that in the AIDS patient with persistent diarrhea who may develop a parasitic disease as did in this case, frequent fecal examinations should be conducted.

Comparison of ipsilateral activation between right and left handers: a functional MR imaging study

We used fMRI to compare the ipsilateral activation in the sensorimotor region (SMR) during dominant and non-dominant hand motor tasks between right and left handers. In right handers, the ipsilateral activation was significantly greater during non-dominant (left) hand task than dominant (right) hand task, while in left handers, it showed no significant difference. The ipsilateral activation was most pronounced in the precentral subregion (presumably corresponding to the premotor area) during either hand task in both groups. We conclude that the different patterns of ipsilateral activation might be mainly explained by the hemispheric dominance. The skill of the hand and complexity of tasks may be related to the predominant activation of the premotor area.

Hyperplastic foci reflect the risk of multicentric development of human hepatocellular carcinoma

BACKGROUND/AIMS

Identification of the risk factors of multicentric hepatocarcinogenesis is important for the clinical management of hepatocellular carcinoma. We investigated hyperplastic foci in non-cancerous liver parenchyma, and clarified their pathological features and clinical significance.

METHODS

Hyperplastic foci were defined as hypercellular areas, which architecturally and cytologically resembled early hepatocellular carcinoma or adenomatous hyperplasia but did not form macroscopically detectable nodules. Surgically resected livers from 155 patients with hepatocellular carcinoma were examined histopathologically and immunohistochemically.

RESULTS

Hyperplastic foci were found in 26 of 155 patients (16.8%). All the patients with hyperplastic foci had chronic liver diseases, and the incidence did not differ between those with chronic hepatitis and those with liver cirrhosis. Six of 92 (6.5%) patients with single primary hepatocellular carcinoma nodules, 8 of 42 (19.0%) with two nodules, and 12 of 21 (57.0%) with more than three nodules had hyperplastic foci. The incidence of hyperplastic foci showed a significant positive correlation with the multiplicity of hepatocellular carcinoma nodules. Immunohistochemically, hyperplastic foci were masses of proliferative hepatocytes similar to adenomatous hyperplasia and early hepatocellular carcinoma.

CONCLUSIONS

Hyperplastic foci reflect the risk of multicentric hepatocarcinogenesis. Our results suggest strongly that hyperplastic foci are precursors of adenomatous hyperplasia or hepatocellular carcinoma.

A second primary squamous cell carcinoma arising in a radial forearm flap used for reconstruction of the hypopharynx

A 63-year-old man had undergone hypopharyngectomy for hypopharyngeal carcinoma in 1985. A free radial forearm flap was used for reconstruction of the pharynx. Ten years after the surgery, a second primary squamous cell carcinoma occurred in the neopharynx. Persistent exposure to alcohol, saliva and foodstuffs was considered as a possible cause of second primary carcinoma. Long-term follow-up is indicated in patients undergoing reconstruction using cutaneous or musculocutaneous flaps.

An intravascular chemoattractant lectin inhibits neutrophil migration

KM+, a lectin purified from Artocarpusintegrifolia seeds, is an attractant for neutrophils, and has properties similar to fMLP, IL-8 and MNCF. The endogenous lectin MNCF, inhibits carrageenan-induced neutrophil migration when intravenously administered in rats. In an attempt to mimic the activity of MNCF with KM+, we determined the effect of intravenous (iv) injection of KM+ (5 microg) on neutrophil migration to the peritoneal cavity of Wistar rats induced by KM+ (50 microg, intraperitoneal, ip), fMLP (5 ng, ip) and carrageenan (300 microg, ip). Initially we evaluated the effect of the time interval between intravenous and intraperitoneal administration of KM+. The intervals ranged from 20 to 120 min and progressively stronger inhibition was observed with increasing time intervals up to a maximum of 60 min, with effect decreasing thereafter. With injections at the optimum interval of 60 min, we observed that KM+ inhibited KM+- and carrageenan-induced neutrophil migration by 72%, and fMLP-induced migration by 56%. White cell counts for Wistar rats that only received KM+iv, performed at 0 to 120 min intervals after injection, revealed early neutropenia lasting 60 min, followed by a marked increase in circulating neutrophils that reached a maximum of twice the initial levels within 90 min and after 120 min returned to levels near to that observed before intravenous administration of KM+. These results indicate that when KM+ is present in the intravascular space, it produces an inhibitory effect on neutrophil migration similar to that caused by the intravenous administration of other chemoattractants, regardless of whether they act through a mechanism independent of carbohydrate recognition, as does IL-8, or are dependent on carbohydrate recognition, like MNCF.

Needle tract implantation of hepatocellular carcinoma after percutaneous ethanol injection

BACKGROUND

Percutaneous ethanol injection (PEI) therapy currently is widely used for small hepatocellular carcinoma (HCC). However, only limited information is available regarding needle tract implantation after PEI treatment.

METHODS

Records of HCC patients who underwent PEI between March 1990 and April 1997 at the National Cancer Center Hospital (n = 177) were reviewed to clarify the incidence, risk factors, and outcome of needle tract implantation of HCC.

RESULTS

PEI was performed for 348 HCC patients with a median tumor size of 20 mm. Needle tract implantation was found in 4 patients (10, 13, 15, and 46 months, respectively, after PEI). The size of the PEI-treated HCC tumors in these patients was 20, 27, 28, and 30 mm, respectively, in greatest dimension. All tumors were enhanced in the early phase on dynamic computed tomography (CT), and were found to have moderate tumor cell differentiation on biopsied specimens. Of the four implanted tumors, three were resected and the remaining tumor was treated with extrabeam radiotherapy. At last follow-up, 2 of the 4 patients had died (1 of variceal bleeding 60 months after PEI and the other from cancer 61 months after PEI) and 2 were still alive (14 and 20 months, respectively, after PEI) with no evidence of active tumor.

CONCLUSIONS

Needle tract implantation after PEI is not unusual, especially when HCC tumors are > or =2 cm in greatest dimension, enhanced in the early phase on dynamic CT, and/or moderately differentiated on biopsied specimens.

Physiologic role of the complement system in host defense, disease, and malnutrition

The role of the complement system as a system merging early-phase innate immunity with later-phase acquired immunity has been established. C3 is a key protein of the complement system. It is activated in four pathways: (1) the alternative pathway, (2) the mannan binding protein pathway, (3) the C-reactive protein pathway, and (4) the natural IgM pathway in innate immunity. It is also activated in (1) a classic pathway, i.e., through an antigen-antibody complex, and (2) by injured host cells in acquired immunity. Activation of C3 results in a variety of immunologic reactions such as immune adherence, phagocytosis, antibody response, cytolysis, inflammation, and killing of pathogenic microorganisms. Pathologic pictures of the complement system in various diseases were reviewed. Attention was focused on hypocomplementemia in the malnourished state. In humans and in experimental animals, reduced complement levels, especially of C3, were observed in relation to lowered host defense against infection. Hypocomplementemia improved after nutritional rehabilitation with a concomitant improvement of the clinical picture and recovery of host resistance. Enhancement of C3 levels in malnourished or well-nourished rats resulted in heightened resistance against bacterial infections. On the basis of these experimental and clinical observations, we obtained clues to prevent or treat a compromised host defense system in malnourished states.

[Evaluation of blood flows inside hepatic tumors using color Doppler echography with galactose-based intravenous contrast medium "SH/TA 508" administration]

The purpose of this study is to evaluate hemodynamic characteristics of various hepatic tumors using color Doppler echography administered galactose-based intravenous contrast medium "SH/TA 508 (Levovist)". Subject were 9 cases of hepatocellular carcinomas, 5 cases of metastatic liver tumors and a case of hemangioma. We evaluated the characteristics of blood flows inside various hepatic tumors, and also evaluated the first pass through the hepatic tumors during administration of Levovist. The strongly pulsatile branched blood flows inside tumor and the slow-increased and plateau patterns were observed in the all cases of hepatocellular carcinomas, the weakly pulsatile blood flows surrounding tumor and the rapid-increased and slow-decreased patterns were observed in the cases of metastatic liver tumors, and the continuous blood streams in the margin of tumor and the slow-increased and slow-decreased pattern were observed in the case of hemangioma. These findings were characteristic in various hepatic tumors, and color Doppler echography enhanced by Levovist was very useful to distinguish hepatic tumors.

UL-FS 49 (zatebradine) does not affect arterial baroreflex in conscious normal or aortic-constricted rats

Heart-rate reduction is an important element of patient management during cardiac bypass surgery and in therapeutic measures for combating ischemia and relieving pain in patients with angina. UL-FS 49 is a novel bradycardic agent that purportedly acts solely on the sinoatrial node without potentially deleterious effects on arterial pressure and cardiac inotropism. However, little is known about influences of this agent on neuronal tissue and cardiovascular reflexes. Moreover, left ventricular hypertrophy, which often accompanies cardiovascular disease, is known to attenuate the arterial baroreflex and could have effects interactive with those of UL-FS 49. In this study, the effects of UL-FS 49 on the arterial baroreflex were tested in normal rats (N), rats with left ventricular hypertrophy 14 days after abdominal aortic constriction (AC), and sham-operated controls (SH). Arterial baroreflex sensitivity (BRS) was estimated as the slope of the relation between mean arterial pressure (independent variable) and the RR interval (dependent variable). At the time of study, the AC group had significantly greater mean arterial pressure than either SH or N (159 +/- 2, 122 +/- 3, and 124 +/- 3 mm Hg, respectively; mean +/- SEM, p < 0.01) and significantly greater left ventricular mass to body mass ratio than did SH (3.73 +/- 0.11, 2.33 +/- 0.11 mg/g; p < 0.01). As expected, BRS was significantly depressed in AC, compared with either SH or N (0.52 +/- 0.16, 1.48 +/- 0.12, 1.69 +/- 0.25 ms/mm Hg, respectively; p < 0.01). Despite its potent dose-dependent bradycardic effects in all three groups, UL-FS 49 did not affect BRS significantly in any group. These results show that the arterial baroreflex is largely unaffected by UL-FS 49 in both normal rats and rats with systemic hypertension and left ventricular hypertrophy.

Lower than normal expression of brain nitric oxide synthase gene in the hypothalamus of deoxycorticosterone acetate-salt hypertensive rats

OBJECTIVE

To elucidate the role of brain nitric oxide produced by neuronal constitutive nitric oxide synthase in sodium-induced hypertension.

DESIGN AND METHODS

Diets containing a high (8% NaCl), a medium (2% NaCl), and a low (0.2% NaCl) sodium content were administered to Wistar rats aged 12 weeks for 10 days or 8 weeks until they were killed. Male Wistar rats administered either deoxycorticosterone acetate, 1% NaCl or both and the respective controls were killed 2 weeks (during prehypertensive stage) or 6 weeks (during hypertensive stage) after the start of treatment. The hypothalamus and lower brainstem were excised for extraction of total RNA. Reverse transcription polymerase chain reactions of constitutive nitric oxide synthase messenger RNA and glyceraldehyde-3-phosphate dehydrogenase messenger RNA were performed, and constitutive nitric oxide synthase messenger RNA levels were expressed relative to glyceraldehyde-3-phosphate dehydrogenase messenger RNA levels.

RESULTS

A high sodium intake for 10 days tended to decrease constitutive nitric oxide synthase messenger RNA levels in the hypothalamus, compared with effect of a low sodium intake. Constitutive nitric oxide synthase messenger RNA levels in the hypothalamus of deoxycorticosterone acetate-salt hypertensive rats were lower than those in the control sham-operated rats. Neither alteration of sodium intake nor administration of deoxycorticosterone with and without sodium affected constitutive nitric oxide synthase gene expression in the lower brainstem.

CONCLUSIONS

Expression of neuronal constitutive nitric oxide synthase gene is downregulated in the hypothalamus of deoxycorticosterone acetate-salt hypertensive rats. This lower than normal expression of neuronal constitutive nitric oxide synthase gene in the hypothalamus could be an adaptive response to sodium-induced hypertension, and suggests that nitric oxide produced by hypothalamic constitutive nitric oxide synthase plays a role in maintenance of blood pressure in relation to sodium balance in rats.

GABAergic inhibition of hiccup-like reflex induced by electrical stimulation in medulla of cats

We hypothesize that the hiccup reflex is actively inhibited through GABA(B) receptor within central connections of the hiccup reflex arc. Because the hiccup-like reflex can be elicited by electrical stimulation to a limited area within the medullary reticular formation, the hiccup-evoking site (HES), electrical stimulation (50-100 microA, three train pulses at 20 Hz) was delivered to HES by means of a metal electrode containing 1.0 mM baclofen, in anesthetized spontaneously breathing cats. The evoked response was characterized by a brief powerful increase in diaphragmatic activity and a temporal suppression of the posterior cricoarytenoid muscle, laryngeal dilator, which corresponded to the fixed motor pattern of hiccup reflex. The hiccup-like response was rapidly suppressed after microinjection of baclofen (0.1-0.5 nmol) into HES, indicating that HES has GABA(B) receptors. In the other experiments, to histologically examine the inputs to the hiccup reflex arc, unconjugated cholera toxin subunit B (UCTB) was injected into HES. Following injections of UCTB, retrogradely labelled cells were found distributed in various areas of the lower brainstem. Among these areas, the nucleus raphe magnus (RM) is reported to have GABA-containing cells. It is thus hypothesized that RM is most likely to be the source of the GABAergic inhibitory inputs to the hiccup reflex arc.

Aortitis syndrome (Takayasu's arteritis) with cataract and elevated serum level of vascular endothelial growth factor

The aortitis syndrome is a chronic inflammatory process that affects the aorta and its primary branches. Patients with aortitis syndrome exhibit various ocular changes. We present a patient in whom cataract was the initial objective finding. The serum concentration of vascular endothelial growth factor, a cytokine that affects neovascularization, and vasopermeability, was elevated before the initiation of prednisolone treatment. Cataract should be considered as a possible characteristic initial finding in patients with aortitis syndrome. Vascular endothelial growth factor may be involved in the progression of aortitis syndrome.

Alpha 2-adrenoceptor-mediated antisecretory effect of hypoxia in conscious rats

Gastric acid secretion is suppressed, resulting in a significant rise in gastric pH, when conscious rats are exposed to hypoxia (Yamaji et al., 1996). When adrenal medullectomized rats were exposed to moderate (10.5% O2) hypoxia for 3 h, gastric acid secretion was restored to nearly the level in normoxia by the adrenal medullectomy. In severe (7.6% O2) hypoxia, the operation also caused an increase in the level of gastric acid output, although the extent was lower than that under 10.5% O2 hypoxic conditions. Gastric pH was normalized by the operation even with 7.6% O2 hypoxia. Similar results were obtained when reserpine, which causes an adrenergic discharge, was administered. When an alpha 2-adrenoceptor blocking agent, yohimbine, was administered, the inhibitory effect of 10.5% and 7.6% O2 hypoxia on gastric acid secretion was almost completely removed. However, neither prazosin (an alpha 1-adrenoceptor blocker) nor propranolol (a beta-adrenoceptor blocker) showed any significant effects on gastric acid output in hypoxia. These results indicate that acute hypoxia stimulated the adrenergic response from the adrenal medulla, and that gastric acid secretion was consequently suppressed through alpha 2-adrenoceptor.

Widespread neuronal degeneration in rats following oral administration of methylmercury during the postnatal developing phase: a model of fetal-type minamata disease

The neurotoxicity of methylmercury (MeHg) treatment during the postnatal developing phase in rats was studied. Rats on postnatal day 1 were orally administered 5 mg/kg/day methylmercury chloride (MMC) for more than 30 consecutive days. Body weight loss began 26 days after MMC was administered, and severe paralysis of the hind-limbs and unsteadiness appeared subsequently. Histopathologically, the widespread neuronal degeneration was observed in the cerebral neocortex, neostriatum, red nucleus, brainstem, cerebellum and spinal dorsal root ganglia on day 32. The widespread distribution of the lesions was quite similar to that in fetal cases of MeHg intoxication in Minamata, Japan. These findings suggest that MMC treatment during the postnatal development phase in rats produce a good model of fetal-type Minamata disease.

Dynamics of human cardiorespiratory responses to standing on one leg with eyes closed

The postural control system has been extensively studied in terms of somatic motor function but little is known about its connection with human autonomic function. The purpose of this study was to determine the cardiorespiratory changes in response to the 1-min balance test that was performed by standing on one leg with eyes closed (SOLEC) or eyes open (SOLEO) in 12 healthy young women [mean age 20.7 (SD 3.3) years]. Heart rate (HR), respiratory rate (RR), duration of inspiration and expiration, tidal volume (VT), and oxygen uptake (VO2) were measured during the test. The SOLEC test produced rapid increases in HR at the onset. There were significant increases in HR later during the test (P < 0.05). Metabolic rate (VO2) showed a gradual increase during the SOLEC test, indicating that the late responses could have been partly due to metabolic changes. The RR increased significantly at the onset of the test (P < 0.05), and remained elevated until the end of the test. The early responses were considered to be mediated neurally through the postural control system which receives the afferent inputs arising from the vestibular system and from muscle proprioceptors of the leg. In contrast, SOLEO caused small insignificant changes in HR, RR, VT and VO2, suggesting that a visual input is essential for balancing a postural change. The SOLEC test may have potential as a test of autonomic function.

Skin vasomotor reflex predicts circulatory responses to laryngoscopy and intubation

BACKGROUND

An evaluation of autonomic reactivity may help to predict circulatory responses to intubation. The relation between the magnitude of the skin vasomotor reflex (SVmR) immediately before laryngoscopy and the circulatory responses to intubation was examined.

METHODS

Forty-four adult patients (classified as American Society of Anesthesiologists physical status I or II) were studied. General anesthesia was induced with fentanyl and thiamylal and maintained with nitrous oxide and sevoflurane. The SVmR was evoked by an electrostimulus to the ulnar nerve, and decreases in skin blood flow were detected using a laser-Doppler flowmeter. In study 1, two groups of patients were studied. In the monitored group (n = 14), laryngoscopy was performed when the SVmR amplitude had decreased to less than 0.1. In the control group (n = 15), intubation was performed regardless of changes in the SVmR amplitude. In study 2, after induction, the end-tidal concentration of sevoflurane was maintained at 1 MAC (n = 9) or 1.3 MAC (n = 6) for 5 min. The SVmR was tested by changing the electric intensity.

RESULTS

In study 1, the blood pressure and heart rate of the control group increased significantly (P < 0.01) after laryngoscopy. The blood pressure of the monitored group did not increase. The SVmR amplitude and the systolic blood pressure changes showed a significant linear correlation (P < 0.001). In study 2, the relation between the electric intensity and the SVmR amplitude showed a weak but significant correlation (P < 0.01) in the 1 MAC group.

CONCLUSION

The evaluation of the SVmR provides useful information for determining the optimal anesthetic depth for laryngoscopy and intubation in individual patients.

[The history and current state of communication avoidance research]

The ability to communicate effectively has a profound impact on academic ability and social status in the United States. As such, communication avoidance may impart critical consequences on individuals who suffer from it. Within the communication discipline, communication avoidance is an extensive body of research with a relatively long history. Central to communication avoidance research is the concept of communication apprehension (CA). However, in comparison with research conducted in the United States, CA research in Japan remains in its genesis. This review thus focuses on communication apprehension and related constructs. Starting with an explanation of the magnitude of the problem of communication avoidance, a definition of CA is presented, and an overview of the related constructs of reticence, shyness, and other communication-related fears is introduced. Basic CA treatment programs and personality correlates of CA are also covered. The review closes by offering suggestions for future CA research in Japan.

Functional MR imaging of cortical activation of the cerebral hemispheres during motor tasks

PURPOSE

We used functional MR imaging to evaluate cortical activation in the precentral, central, and postcentral regions of the contralateral and ipsilateral cerebral hemispheres during left- and right-handed motor tasks.

METHODS

Ten healthy right-handed volunteers were studied with echo-planner MR imaging (1.5 T) while performing alternating finger apposition tasks with both hands. During the hand tasks, the areas of activated pixels were compared between subregions (precentral, central, and postcentral) of the contralateral and ipsilateral sensorimotor cortex.

RESULTS

The activated area of the contralateral sensorimotor cortex was significantly larger than that of the ipsilateral cortex during tasks with either hand, whereas the ipsilateral activated area was significantly larger during the left-handed task than during the right-handed task. Ipsilateral activation was greatest in the precentral region, less in the central region, and least prominent in the postcentral region.

CONCLUSIONS

Our results confirmed those of previous investigators that ipsilateral activation is more pronounced during left-sided movements than during right-sided movements. The variation in activation of the precentral, central, and postcentral subregions suggests different roles of the ipsilateral and contralateral hemispheres during motor tasks.