Response of leptin mRNA to 24-h food deprivation and refeeding is influenced by age in rats

To obtain an insight into the influence of aging on leptin gene expression, the responses of leptin mRNA in retroperitoneal and epididymal adipose tissues and plasma leptin concentrations to 24-h food deprivation and refeeding were examined in 2-, 10- and 24-month-old normal rats. The basal level of leptin gene expression in retroperitoneal adipose tissue was significantly higher in 10- and 24-month-old rats than that in 2-month-old rats, while the level in epididymal adipose tissue was highest in 10-month-old rats for all three age groups. The basal concentrations of plasma leptin was significantly higher in 10- and 24-month-old rats than those in 2-month-old rats. The 24-h food deprivation was followed by a significant reduction in leptin mRNA expression in both retorperitoneal and epididymal adipose tissues for all three age groups. The leptin gene expression was restored to control levels 24 h following refeeding in the 2- and 10-month-old rats, but failed to be restored in the 24-month-old rats. In addition, the time course of recovery for leptin mRNA expression by refeeding to the control levels differed between the retroperitoneal and the epididymal adipose tissue in 2- and 10-month-old rats. The concentrations of plasma leptin 24 h following refeeding were compatible with the leptin mRNA levels in adipose tissues in three age groups. These results suggest that the expression of the leptin gene in response to food-deprivation and refeeding is influenced by an animal's age and that this expression is different for different regions of white adipose tissue.

Upregulation of retinal vascular endothelial growth factor mRNAs in spontaneously diabetic rats without ophthalmoscopic retinopathy. A possible participation of advanced glycation end products in the development of the early phase of diabetic retinopathy

Vascular endothelial growth factor (VEGF) has recently been shown to be involved in the pathogenesis of proliferative diabetic retinopathy. However, its involvement in the development of the early phase of diabetic retinopathy is not fully understood. In this study we investigated the retinal VEGF mRNA level in spontaneously diabetic Otsuka Long-Evans Tokushima fatty (OLETF) rats, a model of non-insulin-dependent diabetes, without overt retinopathy, using quantitative reverse-transcription polymerase chain reaction. The retinal VEGF mRNA level was 2.2 times higher (p < 0.0005) in OLETF rats than in control rats at the age of 60 weeks. Moreover, their retinal mRNA level was positively correlated with serum concentration of advanced glycation end products (AGEs) but not to serum glucose concentration. Furthermore, the peak latency of the oscillatory potentials in the electroretinogram, one of the most sensitive markers for the early phase of diabetic retinopathy, was significantly prolonged in OLETF rats (p < 0.05), being also correlated with the serum AGE concentration. The results thus suggest that AGEs, which are formed acceleratedly in diabetic conditions, are involved in the development of the early phase of diabetic retinopathy probably through the induction of retinal VEGF mRNAs.

Solitary fibrous tumor of the meninges in the posterior cranial fossa: magnetic resonance imaging and histological correlation--case report

A 58-year-old female presented with a rare case of intracranial solitary fibrous tumor (SFT) manifesting as progressive ataxic gait and hearing loss on the left persisting for 6 months with recent symptoms of increased intracranial pressure. Computed tomography demonstrated a large isodense irregular-shaped mass in the left posterior cranial fossa. T2-weighted magnetic resonance imaging showed two components appearing as very low intensity and high intensity. Extreme-lateral suboccipital craniotomy was performed. Gross total resection was achieved except for some dural attachment in the jugular foramen. All symptoms and signs subsided after surgery. Histological, immunohistochemical, and electron microscopic examinations led to a diagnosis of SFT. The strongly hypointense areas on the T2-weighted images were hypocellular region characterized by disorganized spindle cells and thick bands of collagen. The hyperintense areas on the T2-weighted images were hypercellular region mimicking hemangiopericytoma. Strong immunoreactivity for CD34 was also helpful in the diagnosis. Electron microscopy revealed absence of pinocytic vesicles and dense laminae which are characteristic of hemangiopericytoma. The magnetic resonance imaging appearance of SFT seems to be pathognomonic.

A quantitative analysis of head injury using T2*-weighted gradient-echo imaging

BACKGROUND

T2*-weighted gradient-echo imaging (T2*-GE) is useful for detecting small hemorrhages.

METHODS

Thirty-four patients were prospectively examined, first by magnetic resonance imaging (1.5 T) and then by T2-weighted fast spin echo (T2-FSE) and T2*-GE. Thereafter, the correlations between the T2-FSE or T2*-GE findings and the clinical or computed tomography findings were analyzed.

RESULTS

The number of lesions detected by T2*-GE was 14.5 +/- 16.3 (mean +/- SD, n = 34), which was significantly (p < 0.001) greater than that detected by T2-FSE (5.6 +/- 5.6, n = 34). The findings of T2*-GE correlated positively with both the duration of unconsciousness (R2 = 0.74,p < 0.0001) and with Glasgow Outcome Scale (R2 = 0.81, p < 0.0001), whereas those of T2-FSE did not show any significant correlation. T2*-GE imaging could also detect all areas responsible for focal neurologic signs 1 month after in. jury, whereas T2-FSE imaging detected only 22 of 33 such signs.

CONCLUSION

T2*-GE was found to be useful for evaluating the clinical symptoms of head injury.

Serum leptin profiles in the normal menstrual cycles and gonadotropin treatment cycles

Circulating levels of leptin, estradiol (E(2)) and progesterone (P(4)) throughout normal menstrual cycles (n = 13), and controlled, stimulated cycles (n = 33) were examined using sensitive specific radioimmunoassays in order to investigate the relationships between sex hormones (E(2), P(4)). Serum leptin levels during the normal menstrual cycle remained constant. However, in the ovulation induction cycle, E(2) levels and circulating leptin levels increased in parallel with the process of stimulation. In addition, leptin/body mass index ratios for all samples were significantly correlated with log(10)E(2). We conclude that particularly high levels of E(2) may have an effect on the secretion of leptin from adipose tissue.

High susceptibility to cerebral ischemia in GFAP-null mice

Astrocytes perform a variety of functions in the adult central nervous system (CNS) that contribute to the survival of neurons. Thus, it is likely that the activities of astrocytes affect the extent of brain damage after ischemic stroke. The authors tested this hypothesis by using a mouse ischemia model to compare the infarct volume produced in wild-type mice with that produced in mice lacking glial fibrillary acidic protein (GFAP), an astrocyte specific intermediate filament component. Astrocytes lacking GFAP have been shown to have defects in process formation, induction of the blood-brain barrier. and volume regulation; therefore, they might be compromised in their ability to protect the CNS after injury. The authors reported here that 48 hours after combined permanent middle cerebral artery occlusion (MCAO) and 15 minutes transient carotid artery occlusion (CAO) GFAP-null mice had a significantly (P < 0.001) larger cortical infarct volume (16.7 +/- 2.2 mm3) than their wild-type littermates (10.1 +/- 3.9 mm3). Laser-Doppler flowmetry revealed that the GFAP-null mice had a more extensive and profound decrease in cortical cerebral blood flow within 2 minutes after MCAO with CAO. These results indicated a high susceptibility to cerebral ischemia in GFAP-null mice and suggested an important role for astrocytes and GFAP in the progress of ischemic brain damage after focal cerebral ischemia with partial reperfusion.

Analysis of experimental autoimmune encephalomyelitis induced in F344 rats by pertussis toxin administration

To elucidate the factor(s) accelerating the autoimmune disease processes, we induced two types of experimental autoimmune encephalomyelitis (EAE), severe and very mild, in F344 rats by immunization with myelin basic protein (MBP) plus pertussis toxin (PT) (PT+) or with MBP alone (PT-) and compared the differences between the two. Immunohistochemical examinations showed that although the nature of inflammation was essentially the same between the two groups, the proportion of Vbeta8.2(+) T cells in the CNS lesion of PT (+) rats was larger than that of PT (-) rats. Cytokine analysis by competitive PCR revealed that IL-10 mRNA in the lymphoid organ was significantly suppressed in the PT(+) group, whereas levels of IFN-gamma,TNF-alpha and TGF-beta mRNA were insignificantly different after PT administration. In addition, T cells taken from PT (+) rats proliferated well in response to MBP, while those from PT (-) rats showed a marginal response to the same antigen. However, this finding does not indicate the switching of non-encephalitogenic to encephalitogenic T cells upon PT administration because PT (-) rats contained encephalitogenic T cells and/or their precursor cells as revealed by adoptive transfer experiments. Taken together, these findings suggest that suppression of IL-10 by PT administration is the major factor contributing to the exacerbation of EAE in PT(+) rats.

Neuronal activity in the primate prefrontal cortex in the process of motor selection based on two behavioral rules

This study examined neuronal activity in the prefrontal cortex (PF) involved in the process of motor selection in accordance with two behavioral rules. We trained two monkeys to select a target based on the integration of memorized and current sensory information. Initially, a sample cue (triangle or circle) appeared at one of three locations (top, left, or right) for 1 s. After a 3-s delay, one of two types of choice cue appeared. The first type asked the monkeys to reach for a target by matching the location (location-matching task). The second type asked the monkeys to reach for a target by matching the shape (shape-matching task). The choice cue for location matching consisted of either three circles or three triangles, and the choice cue for shape matching consisted of a circle and a triangle. When the color of the choice cue changed from red to green 1.5 s later (GO signal), the monkeys touched the correct object to obtain a reward. We found cue-, delay-, choice-, and movement-related neuronal activity in the lateral prefrontal cortex. During the sample cue presentation and delay periods, we found selective neuronal activity for the location or shape of the sample cue. Shape-selective neurons were located more anteriorly in the ventral bank of the principal sulcus and inferior convexity area, whereas location-selective neurons were more posteriorly. After the choice cue appeared, we found three main types of neuronal activity in the critical period when the subject selected the future target: 1) activity reflecting past sensory information (the location or shape of the sample cue presented 3 s earlier), 2) activity selective for the configuration of the current choice cue, and 3) activity reflecting the properties (location or shape) of the future target. During the motor-response period, we found neuronal activity selective for the location or shape of the reaching target. When muscimol was microinjected into the ventral bank of principal sulcus and inferior convexity area, the performance of both tasks was impaired. Furthermore, we found that the wealth of neuronal activity in the PF that seemed to play a role in motor selection was rarely seen in the primary motor cortex.

Pretreatment with continuous-wave ultraviolet irradiation to prevent the development of delayed vasospasm in the rabbit common carotid artery model

OBJECT

Ultraviolet (UV) light irradiation can lead to immunomodulation. The purpose of this study was to determine the preventive effect of UV light on cerebral vasospasm by using a rabbit common carotid artery (CCA) model.

METHODS

Rabbit CCAs were constricted for a long period by application of autologous blood within a silicon sheath. Before immersion in blood, the CCAs were adventitiously exposed to UV light emitted from a helium-cadmium laser (wavelength 325 nm) yielding an irradiation energy of 10 mJ/mm2. The occurrence of vasospasm was evaluated using angiography 48 hours after blood exposure in this model. The UV light treatment significantly reduced the degree of vasospasm. Compared with luminal diameters measured on Day 0, prior to treatment, the luminal diameters of UV light-treated arteries (six animals) decreased by only 6%, whereas that of the sham-treated arteries (eight animals) significantly decreased by 26% (p<0.001). Histological examination of UV light-treated CCAs revealed no endothelial damage and extended smooth-muscle cells, in which some fragmented nuclei were confirmed by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling. Twenty-eight days after blood exposure, examination of UV light-treated CCAs revealed only myointimal proliferation, similar to that of the sham-treated CCAs.

CONCLUSIONS

These results are the first to provide evidence of a prophylactic effect of UV light on vasospasm and are suggestive of involvement of apoptosis in the mechanism of this effect.

Significance of shock in head-injured patients with skull fracture

The clinical differences between patients with skull base and convexity fractures were retrospectively investigated in 324 patients, of whom 110 had suffered head injury resulting in skull fracture. These 110 patients were divided into the skull base and convexity groups. There were no significant differences between the groups with respect to sex, age, Glasgow Coma Scales, injury severity scores, pupil abnormalities, and outcomes. Automobile collisions were the most common causes in the skull base group, and falls in the convexity group. Traumatic Coma Data Bank diffuse 1 type injuries were more frequent in the skull base group and evacuated masses were more frequent in the convexity group. Multiple injuries, shock on admission, lower hemoglobin concentrations, and increased transfusion requirements were evident in the skull base group. Controlling for shock, the outcomes in the skull base group were favorable. Convexity fractures were usually associated with isolated severe head injuries and require brain protection therapy. Skull base fractures were caused by a significant force distributed over a large area of the body with a tendency to induce shock, and require a multidisciplinary approach to treatment.

Real-time monitoring of glutamate following fluid percussion brain injury with hypoxia in the rat

In the present study, extracellular glutamate (Glu) was monitored in real time using an enzyme electrode biosensor following traumatic brain injury (TBI) either with or without inducing hypoxia in the rat. We also measured the cortical contusion volume at 3 days after insult by staining with 2,3,5-triphenyltetrazolium chloride (TTC). Male Sprague-Dawley rats (300-400 g) were anesthetized and then subjected to lateral fluid percussion (FP) brain injury of moderate severity (3.5-4.0 atm), using the Dragonfly device model (no. HPD-1700). The experimental animals were divided into four groups. Group 1 (n = 10) was subjected to TBI only, group 2 (n = 10) to TBI followed by 20 min of moderate hypoxia (FiO2: 10%), group 3 (n = 4) to 20 min of moderate hypoxia without TBI, and group 4 (n = 4) to sham. Seventy-two hours after the insults, the animals were sacrificed, their brains were stained with TTC, and the lesion volumes were calculated. A surge in the extracellular Glu concentration occurred immediately after TBI in groups 1 and 2. There was no significant difference between the two groups. Group 2 showed a prolonged efflux of Glu during hypoxia ( < 0.05). In group 3, Glu continued to show a mild increase. The cortical contusion volume in group 2 was significantly larger than that in group 1. To evaluate the possible involvement of apoptosis in groups 1 and 2, separate rats were sacrificed under the same procedures after 1, 6, 24, and 72 h after insult (n = 2/group). Immunohistochemical analysis demonstrated an increased number of both the cysteine protease caspase-3-positive cells at 24 h and TUNEL-positive cells at 72 h in group 2. These results suggest that TBI with moderate hypoxia induced the prolonged efflux of Glu, which thus resulted in more cortical damage due to necrosis and apoptosis.

Spontaneous activity, sleep, and body temperature in rats lacking the CCK-A receptor

Because of a genetic mutation, the Otsuka-Long-Evans-Tokushima Fatty (OLETF) rat, a model for human non-insulin-dependent diabetes mellitus (NIDDM), shows no expression of the CCK-A receptor gene. We investigated the spontaneous physical activity, sleep, and body temperature in young OLETF rats that had not yet developed diabetes mellitus, and compared these data with age-matched control LETO (non-diabetic strain, Long-Evans-Tokushima-Otsuka) rats. The amount of large movements during the dark phase for the OLETF rats was significantly less than that of control rats. Thus, the amounts of total daily large movement and the ratio of dark-to-light phase movement in the OLETF rats were less than those of control rats, although the amount of small movement was similar for both groups. The diurnal rhythm of body temperature was similar for both groups. In addition, the amount of and circadian rhythm for each vigilance state and slow-wave activity were similar for the two groups. This study demonstrates that the CCK-A receptor might play a role in affecting the level of motor activity, adding hyperphagia, and the circadian rhythm of large movement in these rats prior to the manifestation of NIDDM. In contrast, a CCK-A receptor deficiency does not appear to affect sleep or body temperature in these rats.

Development changes in long-form leptin receptor expression and localization in rat brain

The expression and localization of long-form leptin receptor (OB-Rb) were studied immunocytochemically in the brain of fetal and adult rats using a polyclonal antibody that specifically recognized OB-Rb. At 14 days of gestation, immunoreactive cells were observed in the ventricular layer, which contains premature neuronal cells. At 18 days of gestation, they were weakly stained but obvious in the paraventricular nucleus (PVN), and ependymal cells also showed immunoreactivity. At birth, the immunoreactivity of OB-Rb in the PVN seemed to be much lower than that in adult rats and remained low during the suckling period. Considering the presence of neuroendocrine and structural neuronal abnormalities in Lepob/Lepob mice with genetic leptin deficiency, these results suggest that the expression of OB-Rb in premature neuronal cells may have some function, and that the regulation of energy balance by leptin through hypothalamic regions, such as PVN, may not yet be developed in the perinatal period.

Prevalence of Epstein-Barr virus in oral squamous cell carcinoma

Forty-six samples of oral squamous cell carcinoma (OSCC) were evaluated for the prevalence of Epstein-Barr virus (EBV) infection by the polymerase chain reaction (PCR), Southern blot hybridization, and in situ hybridization (ISH). EBV DNA was detected in 7 (15.2 per cent) out of 46 samples by a combination of PCR and Southern blot hybridization methods. All seven positive samples showed well-differentiated carcinoma, thus suggesting a possible relationship between EBV infection and the degree of differentiation of carcinoma tissue. Latent infection membrane protein 1 (LMP1) was detected immunohistochemically in six of the EBV-positive OSCCs. However, no signal of the EBV-encoded small RNA (EBER)-1 was demonstrated by the ISH method. No significant relationship was observed between EBV infection and lymph node metastasis. A follow-up study (range from 4.4 to 79 months; mean 34.9 months) showed no recurrence or death to occur in the EBV-positive patients, which thus suggested a good prognosis for EBV-positive OSCC patients.

Presence of phospholipid-neutral lipid complex structures in atherosclerotic lesions as detected by a novel monoclonal antibody

A novel monoclonal antibody (ASH1a/256C) that recognizes atherosclerotic lesions in human and Watanabe heritable hyperlipidemic (WHHL) rabbit aortae is described. When (123)I-labeled ASH1a/256C antibody is injected intravenously into WHHL rabbits, it associates specifically with fatty streaks on the aorta. The antigen recognized by the antibody is lipid, based on extraction with chloroform and methanol from WHHL rabbit tissues. The antigen, purified by high performance liquid chromatography, was shown to be phosphatidylcholine (PC), which contains unsaturated fatty acyl groups based on analyses utilizing (1)H and (13)C nuclear magnetic resonance, Fourier transfer-infrared spectrum, and mass spectrometry. The antibody did not react with other classes of phospholipids or neutral lipids when tested using an enzyme-linked immunosorbent assay. When PC was mixed with either cholesterol, cholesteryl ester, or triacylglycerol, however, the reactivity of the antibody to PC increased up to 8-fold. Homogenates of aorta tissue obtained from normal and WHHL rabbits were fractionated using sucrose density gradient ultracentrifugation in which neutral lipid droplets, cellular membranes, and proteins are separated. The phospholipid content in cellular membrane fractions from WHHL rabbits was twice as high as that of normal rabbits, and there was an enormous difference in the antigenic activity in these fractions. The content of cholesterol in the cellular membrane fraction of WHHL rabbits was approximately 50 times higher than that of normal rabbits. Addition of neutral lipids to the cellular membrane fraction of normal rabbit markedly increased the antigenic activity. Atheromatous lesions in thickened WHHL rabbit aortic intima that were rich in lipid droplets were stained positively with ASH1a/256C immunohistochemically. These results strongly suggest that PC-neutral lipid complex domains are formed in atherosclerotic lesions.

Pathoetiology and prevention of NIDDM lessons from the OLETF rat

The OLETF rat, a genetic model of spontaneous development of NIDDM, exhibits hyperglycemic obesity with hyperinsulinemia and insulin resistance similar to that in humans. It is still unclear whether a defect in the beta-cell proliferation per se is the primary pathogenetic event in this model rat. To clarify this matter, we used partially pancreatectomized rats as a model. Male rats of 6 weeks of age were allocated at random to two groups: 70% pancreatectomy (Px) and sham-pancreatectomy (sham). Each group was divided into 4 subgroups by the date of sacrifice after surgery. Sustained hyperglycemia was evident in the Px OLETF rats after surgery. This was associated with insufficient proliferation of beta-cells, characterized by a decrease in beta-cell labeling with 5-bromo-2' deoxyuridine in proportion to a decrease in beta-cell mass and reduction in insulin content in the remnant pancreas. Administration of nicotinamide, however, ameliorated the sustained hyperglycemia by increasing beta-cell proliferation. These findings suggest that OLETF rats have a poor capacity for proliferation of pancreatic beta-cells, and that this change may be the critical pathogenetic event prior to the onset of overt diabetes. OLETF rats following long-term caloric restriction and spontaneous exercise training show normal glucose tolerance accompanied by an increase in GIR as shown by a euglycemic clamp. Both exercise training and caloric restriction normalize the abnormalities in the pancreas such as marked hypertrophy of islets and hyperplasia of connective tissues in islets. It is particularly noteworthy that exercise training significantly elevated the beta-cell mass/body weight ratio. This evidence obtained from OLETF rats may be of value when the mechanism of diet and exercise effects on diabetic patients are considered.

Immunohistochemical and ultrastructural study of a papillary cystadenocarcinoma arising from the sublingual gland

Immunohistochemical and ultrastructural findings in a rare case of papillary cystadenocarcinoma arising from the left sublingual gland of a 55-year-old Japanese man are reported. Histologically, the tumor tissue was found to be composed of various-sized cystic cavities in which papillary epithelial projections with thin fibrovascular cores were observed. The papillary projections consisted of a single layer to several layers of high columnar epithelial cells. Invasion to the surrounding fibrous tissue and into the lymphatics was observed, thus suggesting an aggressive potential in the present case. The possibility of the involvement of myoepithelial cells could be excluded based on the immunohistochemical and ultrastructural findings. The immunohistochemical and ultrastructural findings also suggested that this type of salivary gland tumor, at least the present case, may arise from striated or excretory ducts. There was positive immunostaining for tumor markers CA19-9 and CA125. However, the biological role of these carbohydrate antigens in salivary gland tumors is unclear at present. Further investigations are, therefore, called for to solve this issue.

Large empty sella with an intrasellar herniation of an elongated third ventricle. Case report

A 73-year-old female presented with a large empty sella with herniation of an elongated third ventricle concomitant with herniation of the surrounding subarachnoid space into the sella, manifesting as visual impairment and amenorrhea without galactorrhea. Magnetic resonance imaging and computed tomography cisternography clearly showed the large empty sella, without evidence of either hydrocephalus or benign intracranial hypertension, which is extremely rare.

Colocalization of leptin receptor (OB-R) mRNA and placental lactogen-II in rat trophoblast cells: gestational profile of OB-R mRNA expression in placentae

The present study was designed to clarify the cellular localization and expression of leptin receptor(s) [OB-R(s)] mRNA including its splice variants and their correlation with the cells which secrete placental hormone, placental lactogen-II (PL-II), in rat placentae. By in situ hybridization analysis, hybridization signals for OB-Rb and the common extracellular domain of OB-R were first detectable in some cells of the labyrinth zone of the placentae on day 14 of pregnancy and then a lot of cells dispersed in the entire area of the labyrinth zone expressed OB-Rb during the latter half of pregnancy. However, no expression was observed in the decidua and the junctional zone of the placentae during pregnancy. Double staining study revealed that signals for OB-R expressing trophoblast cells showed PL-II immunoreactivity in the labyrinth zone of the placentae. In Northern blot analysis, two bands (2.8 kb and 5.1 kb) of OB-R mRNA expression were observed in the placentae from day 17 to 21 of pregnancy and the expression of both increased markedly up to day 21 of pregnancy. RT-PCR analysis revealed that OB-Rb, OB-Ra, and OB-Re are expressed in the placentae on days 19 and 21 of pregnancy. These results suggest that the OB-R may have a physiological significance in the placental function during the latter half of pregnancy.

Changes in islet capillary angioarchitecture coincide with impaired B-cell function but not with insulin resistance in male Otsuka-Long-Evans-Tokushima fatty rats: dimorphism of the diabetic phenotype at an advanced age

The Otsuka-Long-Evans-Tokushima fatty (OLETF) rat is a genetic model of spontaneous development of non-insulin-dependent diabetes mellitus (NIDDM) established as an inbred strain after 20 generations of selective breeding. Although they are thought to be genetically homogeneous, they show a dimorphism regarding the diabetic phenotype at an advanced age, with one remaining obese and modestly diabetic while the other becomes lean and overtly diabetic. To clarify the causes for this divergence, we examined the physical, biochemical, and histopathological features in rats at 50 weeks of age, including an analysis of islet angioarchitecture. Sixty-one of 85 male OLETF rats lost weight, while the remainder remained obese. Mean nonfasting plasma glucose in the lean group was 21.8+/-4.6 mmol/L, significantly higher versus the obese group (10.5+/-1.4 mmol/L) and the age-matched control Long-Evans-Tokushima-Otsuka (LETO) group (7.1+/-0.6 mmol/L). Morphological studies of the pancreas from the lean group showed enlarged multilobulated fibrotic islets with a paucity of B cells, whereas islets from the obese group appeared slightly enlarged and showed a relative abundance of B cells. The fine capillaries that form a network in the islets were extremely sparse in the lean group, resulting in a defective glomerular-like configuration, whereas those from the obese group were dense, forming a nearly typical glomerular-like configuration. Increased plasma insulin responses to oral and intravenous (i.v.) glucose and i.v. glucagon loads were nearly absent in the lean group, while they were evident in the obese group, although to a lesser extent compared with the LETO group. Mean insulin secretory output from the perfused pancreas in response to 11.1 mmol/L glucose in the lean group (3.5+/-2.2 pmol/20 min) was significantly lower versus the obese group (8.8+/-6.5 pmol/20 min) and LETO group (22.0+/-10.8 pmol/20 min). Similarly, pancreatic insulin content was significantly lower in the lean group (9.3+/-6.1 microg) versus the others (26.1+/-17.3 microg for obese and 41.1+/-24.8 microg for LETO). In vivo insulin-stimulated glucose uptake measured by a euglycemic clamp technique was significantly higher in the lean group compared with the obese group. These results demonstrate that the dimorphism regarding the diabetic phenotype in male OLETF rats at 50 weeks of age was due to differences in the number of islet B cells, which could be the result of a variation in the capacity for B-cell proliferation among male OLETF rats.

Pharmacokinetic analysis of the cardioprotective effect of 3-(2,2, 2-trimethylhydrazinium) propionate in mice: inhibition of carnitine transport in kidney

The site of action of 3-(2,2,2-trimethylhydrazinium) propionate (THP), a new cardioprotective agent, was investigated in mice and rats. I.p. administration of THP decreased the concentrations of free carnitine and long-chain acylcarnitine in heart tissue. In isolated myocytes, THP inhibited free carnitine transport with a Ki of 1340 microM, which is considerably higher than the observed serum concentration of THP. The major cause of the decreased free carnitine concentration in heart was found to be the decreased serum concentration of free carnitine that resulted from the increased renal clearance of carnitine by THP. The estimated Ki of THP for inhibiting the reabsorption of free carnitine in kidneys was 52.2 microM, which is consistent with the serum THP concentration range. No inhibition of THP on the carnitine palmitoyltransferase activity in isolated mitochondrial fractions was observed. These results indicate that the principal site of action of THP as a cardioprotective agent is the carnitine transport carrier in the kidney, but not the carrier in the heart.

Dysfunctions of the epididymis as a result of primary carnitine deficiency in juvenile visceral steatosis mice

The juvenile visceral steatosis mutant mice serve as an animal model of primary carnitine deficiency, classified as the sudden infant death syndrome. The defect in carnitine uptake was recently found to be due to a defect in the carnitine transporter gene. We herein report, for the first time, the characteristics of epididymal dysfunction in juvenile visceral steatosis mice. At 8-9 weeks of age, the epididymis was deformed and weight was significantly increased. Histologically, the duct of the proximal epididymis was dilated due to the accumulation of an unusually high level of spermatozoa. Spermatozoa were extravasated from the epididymal duct into the stroma. In contrast, the duct of the distal epididymis was constricted and contained no spermatozoa. Thus, the epididymal disorder causes obstructive azoospermia, leading to infertility.

Clinical evaluation of the effect of percutaneous transluminal angioplasty and intra-arterial papaverine infusion for the treatment of vasospasm following aneurysmal subarachnoid hemorrhage

The clinical efficacy of percutaneous transluminal angioplasty and intra-arterial papaverine infusion for treatment of vasospasm following subarachnoid hemorrhage was investigated. Between 1990 and 1993, 84 patients were treated for cerebral vasospasm in National Defense Medical College Hospital. Angioplasty was performed for asymptomatic vasospasm in 18 patients and for symptomatic vasospasm in 12 patients. Intra-arterial papaverine infusion was performed for asymptomatic vasospasm in 10 patients and for symptomatic vasospasm in four patients. The other 40 patients were treated with standard conservative therapy including hypervolemic and hypertensive hemodilution. The outcomes of these patients were analyzed using the Glasgow Outcome Scale. The outcome tended to be better for patients treated with angioplasty, but not for those treated with papaverine infusion, than for those treated conservatively. Recurrence of vasospasm was more frequent after papaverine infusion than after angioplasty. Undesirable complications such as abrupt development of unconsciousness were experienced during papaverine infusion but not during angioplasty. We conclude that percutaneous transluminal angioplasty is superior to intra-arterial papaverine infusion for prevention and treatment of vasospasm following aneurysmal subarachnoid hemorrhage.