Polymerization-induced epitaxy: scanning tunneling microscopy of a hydrogen-bonded sheet of polyamide on graphite.

A molecularly thin film of a two-dimensional polymer network formed by hydrogen bonding was synthesized and investigated with scanning tunneling microscopy. Poly(in-caprolactam) (nylon 6) was epitaxially grown on the basal plane of graphite and an ultrathin film of the polymer was obtained after the bulk materials had been washed away with solvents. The polymer chain has a planar, all-trans conformation and adjacent chains run in the antiparallel direction. This produces complete pairing of hydrogen bonding groups, with each amide group lying on a straight line perpendicular to the polymer backbone. This hydrogen-bonded sheet is oriented so that each polymer backbone lies in the (1010) direction on the graphite hexagonal lattice, as opposed to the (1120) direction taken by other paraffinic molecules studied so far. This experiment shows that hydrogen bonding can be used to control the orientation of macromolecules in two dimensions.

Body water balance and body temperature in vasopressin V1b receptor knockout mice.

In an attempt to determine whether there is a specific vasopressin receptor (V(1b)) subtype involved in the regulation of body water balance and temperature, vasopressin V(1b) receptor knockout mice were used. Daily drinking behavior and renal excretory function were examined in V(1b)-deficient (V(1b)(-/-)) and control (V(1b)(+/+)) mice under the basal and stress-induced condition. In addition, body temperature and locomotor activity were measured with a biotelemetry system. The baseline daily water intake and urine volume were larger in V(1b)(-/-) mice than in V(1b)(+/+) mice. V(1b)(-/-) mice (V(1b)(-/-)) had significantly higher locomotor activity than wild-type, whereas the body temperature and oxygen consumption were lower in V(1b)(-/-) than in the V(1b)(+/+) mice. Next, the V(1b)(-/-) and V(1b)(+/+) mice were subjected to water deprivation for 48 hr. Under this condition, their body temperature decreased with the time course, which was significantly larger for V(1b)(-/-) than for V(1b)(+/+) mice. Central vasopressin has been reported to elicit drinking behavior and antipyretic action, and the V(1b) receptor has been reported to be located in the kidney. Thus, the findings suggest that the V(1b) receptor may be, at least in part, involved in body water balance and body temperature regulation.

Cardiovascular and sympathetic effects of proadrenomedullin NH2-terminal 20 peptide in conscious rats.

Proadrenomedullin NH2-terminal 20 peptide (PAMP) and adrenomedullin (AM), which are derived from the same gene, are novel vasodilative peptides and have been shown to exhibit hypotensive action in anesthetized animals. To avoid the modification via anesthesia, we investigated the effects of intravenously administered PAMP on mean arterial pressure, heart rate (HR), and renal sympathetic nerve activity (RSNA) relative to those of AM in conscious unrestrained rats. We also examined whether the arterial baroreceptor reflex was altered with the two peptides. Intravenous injection of rat PAMP (rPAMP) (10, 20 and 50 nmol/kg) and rat AM (rAM) (0.3, 1.0 and 3.0 nmol/kg) similarly elicited dose-related hypotension accompanied by increases in HR and RSNA. However, the responses to rPAMP were less potent in magnitude and shorter in duration than those to rAM. Moreover, rAM facilitated baroreflex control, whereas rPAMP attenuated it. These findings indicate that although PAMP, as well as AM, may play an important role as a circulating hormone in the systemic circulation of conscious rats, the two peptides derived from an identical origin might have different mechanisms responsible for their cardiovascular and RSNA actions.

Convergence of afferent inputs from the chorda tympani, lingual-tonsillar and pharyngeal branches of the glossopharyngeal nerve, and superior laryngeal nerve on the neurons in the insular cortex in rats.

The responses of single neurons in the insular cortex to electrical stimulation of the chorda tympani (CT), lingual-tonsillar branch of the glossopharyngeal (LT-IXth) nerve, pharyngeal branch of the glossopharyngeal (PH-IXth) nerve, and superior laryngeal (SL) nerve were recorded in anaesthetized and paralyzed rats. Ninety-four neurons responding to stimulation of at least one of the four nerves were identified from the insular cortex. Most of the neurons were located in the posterior portion of the insular cortex; the mean location was 0.8 mm anterior to the anterior edge of the joining of the anterior commissure (AC) and was 1.4 mm dorsal to the rhinal fissure (RF). Of the 94 neurons, 84 (89%) received convergent inputs from two or more nerves, and the remaining 10 (11%) received inputs from one nerve. The neurons responding to the CT stimulation were distributed more anteriorly than those responding to other three nerves in the anterior-posterior dimension. Our results indicate that the neurons recorded mainly from the posterior portion of the insular cortex receive convergent inputs from the oropharyngolaryngeal regions.

Neurons in the posterior insular cortex are responsive to gustatory stimulation of the pharyngolarynx, baroreceptor and chemoreceptor stimulation, and tail pinch in rats.

Extracellular unit responses to gustatory stimulation of the pharyngolaryngeal region, baroreceptor and chemoreceptor stimulation, and tail pinch were recorded from the insular cortex of anesthetized and paralyzed rats. Of the 32 neurons identified, 28 responded to at least one of the nine stimuli used in the present study. Of the 32 neurons, 11 showed an excitatory response to tail pinch, 13 showed an inhibitory response, and the remaining eight had no response. Of the 32 neurons, eight responded to baroreceptor stimulation by an intravenous (i.v.) injection of methoxamine hydrochloride (Mex), four were excitatory and four were inhibitory. Thirteen neurons were excited and six neurons were inhibited by an arterial chemoreceptor stimulation by an i.v. injection of sodium cyanide (NaCN). Twenty-two neurons were responsive to at least one of the gustatory stimuli (deionized water, 1.0 M NaCl, 30 mM HCl, 30 mM quinine HCl, and 1.0 M sucrose); five to 11 excitatory neurons and three to seven inhibitory neurons for each stimulus. A large number of the neurons (25/32) received converging inputs from more than one stimulus among the nine stimuli used in the present study. Most neurons (23/32) received converging inputs from different modalities (gustatory, visceral, and tail pinch). The neurons responded were located in the insular cortex between 2.0 mm anterior and 0.2 mm posterior to the anterior edge of the joining of the anterior commissure (AC); the mean location was 1.2 mm (n=28) anterior to the AC. This indicates that most of the neurons identified in the present study seem to be located in the region posterior to the taste area and anterior to the visceral area in the insular cortex. These results indicate that the insular cortex neurons distributing between the taste area and the visceral area receive convergent inputs from gustatory, baroreceptor, chemoreceptor, and nociceptive organs.

Increase in norepinephrine but not nitric oxide metabolite levels in the hypothalamic paraventricular nucleus region in response to air jet and swing rotation in freely moving conscious rats.

Chronically instrumented, conscious rats were used to examine whether mild exteroceptive stress produces differential neurochemical changes in the hypothalamic paraventricular nucleus (PVN) region. We constructed systems for stress experiment of air jet and swing rotation that were conducted on freely moving conscious rats in a computer-controlled home cage. Concentration of extracellular norepinephrine (NE) and nitric oxide metabolites (NO(X)(-)), nitrite (NO(2)(-)) and nitrate (NO(3)(-)), in the PVN region was then measured by high-performance liquid chromatography with the respective detector; blood pressure (BP) and heart rate (HR) were also measured. Both stressors increased NE concentration in the PVN region as well as BP and HR. Neither stressor altered NO(X)(-) in the PVN region. Cardiovascular and NE changes showed reproducibility in intensity-dependent manner in response to repeated stressors. This finding demonstrated that exteroceptive stress produced different effects on the neurochemical mediators, NE and NO, in the PVN region.

Differential profiles of nitric oxide and norepinephrine releases in the paraventricular nucleus region in response to mild footshock in rats.

The purpose of this study was to determine whether the application of mild intermittent footshock stress can cause changes in the nitric oxide (NO) and norepinephrine (NE) releases in the hypothalamic paraventricular nucleus (PVN) region and medial prefrontal cortex (mPFC). Extracellular levels of NO metabolites and NE in the PVN region and mPFC were determined using an in vivo brain microdialysis technique in conscious rats. In the PVN region, we demonstrated that perfusion of N-methyl-D-aspartate through a microdialysis probe resulted in a dose-dependent increase in NO metabolite levels, whereas intraperitoneal administration of N(G)-nitro-L-arginine methyl ester produced a dose-dependent reduction in the levels of NO metabolites. The levels of NO metabolites in the PVN region increased after intraperitoneal administration of interleukin-1beta in a dose-dependent manner, as we previously reported. This increase in NO metabolite levels was abolished 60 min after systemic administration of N(G)-nitro-L-arginine methyl ester compared to the vehicle-treated control group. Twenty minutes of intermittent footshock induced NE release but did not induce NO release in the PVN region. On the contrary, in the mPFC, 20 min of intermittent footshock induced both NO and NE releases. The present results reveal different patterns and time courses in NO and NE releases between the PVN region and the mPFC in response to mild intermittent footshock stress. These findings are likely to have helpful suggestions for our understanding of the hypothalamic-pituitary-adrenal axis and the limbic forebrain system response to different kinds of stress.

Abdominal vagotomy attenuates interleukin-1 beta-induced nitric oxide release in the paraventricular nucleus region in conscious rats.

Nitric oxide (NO) has recently been shown to modulate the hypothalamic-pituitary-adrenal axis response to interleukin-1 beta (IL-1 beta). We measured levels of nitrite (NO2-) and nitrate (NO3-) in the hypothalamic paraventricular nucleus (PVN) region using an in vivo brain microdialysis technique in conscious rats. Intraperitoneally administered IL-1 beta produced a significant increase in both NO2- and NO3- levels in the PVN region. We also examined the possible involvement of the abdominal vagal afferent nerves in this effect. In abdominal-vagotomized rats, the increase was significantly attenuated compared to that in sham-operated rats. Our results suggest that the abdominal vagal afferent nerves are involved in intraperitoneally administered IL-1 beta-induced NO release in the PVN region.

Fiber types of the lingual branch of the trigeminal nerve, chorda tympani, lingual-tonsillar and pharyngeal branches of the glossopharyngeal nerve, and superior laryngeal nerve and their relation to the cardiovascular responses in rats.

The effect of repetitive electrical stimulation at 50 Hz for 20 s of the lingual branch of the trigeminal nerve (LN), chorda tympani (CT), lingual-tonsillar (LT-IXth) and pharyngeal (PH-IXth) branches of the glossopharyngeal nerve, and superior laryngeal nerve (SLN) on the changes in arterial blood pressure (BP) and heart rate (HR) were investigated in anesthetized and paralyzed rats. The compound action potentials in these nerves were simultaneously recorded to know the relationships between the fiber types and the cardiovascular responses. In all nerves except the CT, repetitive electrical stimulation of the nerve elicited a tachycardia and an increase in BP. These cardiovascular responses were mainly related to the component-2 in the compound action potentials in respective nerves. The conduction velocities of the component-2 in the five nerves examined in the present experiment were between 9.5 and 17.0 m/s (mean, n = 4-7). Other components which have faster (component-1) or slower conduction velocities (component-3 and -4) than the component-2 were not likely to elicit the cardiovascular responses. These results suggest that nociceptive and taste fibers of A-delta fibers innervating the oral cavity and pharyngolaryngeal region largely contribute to the cardiovascular responses.

The ability of gustatory stimuli to modify the cardiac sympathetic and vagus nerve activities.

The effects of chemical stimulation of the oro-lingual mucosa on the heart rate and arterial blood pressure were studied together with changes in the cardiac nerve activities in the rat. Of four qualities of basic taste stimuli, only HCl and NaCl but not quinine and sucrose were effective in increasing the heart rate and blood pressure. These changes in the cardiovascular system were associated with an increase in the efferent cardiac sympathetic activity and a decrease in the vagal activity, although they were no longer appreciable after transection of the glossopharyngeal nerve.

Difference in water intake but not in renal sympathetic nerve activity in response to central salt-loading or angiotensin II in awake Dahl salt-sensitive and -resistant rats.

Experiments were conducted to examine whether renal sympathetic nerve activity (RSNA) and water intake in response to central salt-loading or angiotensin II (A II) differ between freely-moving Dahl salt-sensitive (DS) and -resistant (DR) rats maintained on a low-salt diet. Intracerebroventricular (i.c.v.) administration of hypertonic saline (0.3 M, 1 microl/min, 20 min) or A II (100 ng/1 microl) evoked water intake, pressor response and suppression of RSNA in both strains. The cumulative water intake in DS rats over a 60-min period after i.c.v. infusion of hypertonic saline or A II was significantly attenuated compared with that in DR rats. The RSNA response did not show a significant difference between the strains. These results demonstrate that water intake, but not RSNA response to acute central salt-loading or A II differ between awake DR and DS rats.

Effects of anesthetics on norepinephrine release in the hypothalamic paraventricular nucleus region of awake rats.

The effects of pentobarbital sodium, chloralose and urethane on norepinephrine (NE) release in the hypothalamic paraventricular nucleus (PVN) region were examined in awake rats. An in vivo microdialysis method was used. Extracellular NE concentrations in the PVN region were measured by high performance liquid chromatography with electrochemical detection. Pentobarbital sodium (30 mg/kg, intravenously [i.v.]) and chloralose (50 mg/kg, i.v.) caused a 30-40% decrease in NE release while urethane (800 mg/kg, i.v.) caused a 50% increase. Plasma NE concentration was not altered after pentobarbital sodium and chloralose administrations, except for its increase in chloralose at 5 h, while the concentration increased significantly (P < 0.01) after urethane. These results suggest that, in the rat, these anesthetic agents have different effects on noradrenergic activity in the PVN region as well as on plasma NE.

Effects of area postrema lesion and abdominal vagotomy on interleukin-1 beta-induced norepinephrine release in the hypothalamic paraventricular nucleus region in the rat.

Peripherally administered interleukin-1 beta (IL-1 beta) has been shown to increase extracellular norepinephrine (NE) concentration in the paraventricular nucleus (PVN) of the hypothalamus. The present study was carried out using an in vivo microdialysis technique in conscious rats in order to examine the possible involvement of the area postrema (AP) and the abdominal vagal afferent nerves in this effect. Extracellular NE concentrations in the PVN region were measured by high performance liquid chromatography with electrochemical detection. In AP-lesioned or abdominal-vagotomized rats, the NE increase was significantly attenuated compared to that in sham-operated rats; this reduction was greater in abdominal-vagotomized rats than in AP-lesioned rats. The results suggest that the AP as well as the abdominal vagal afferent nerves is involved in intraperitoneal (i.p.) administered IL-1 beta-induced NE release in the PVN region.

Homogeneous immunoassay based on dihexadecyl-dimethylammonium bilayer membranes.

We describe a rapid, highly sensitive, simple immunoassay based on cationic bilayer membranes prepared from dihexadecyl-dimethylammonium bromide. This detergent was dispersed in water to give a slightly turbid solution which contained lamellar (not vesicular) bilayer membranes with a gel to liquid crystal phase transition (Tc, 28 degrees C). An anionic hapten (N,N'-bis(2,4-dinitrophenyl)-L-lysine) combined electrostatically with this cationic membrane to induce aggregation of membranes, making the solution turbid. This aggregation was suppressed by antibodies to the hapten. The aggregation rate was rapid at a temperature above Tc, and the amount of antibodies was quantified by measuring absorbance or light scattering of the aqueous solution with a detection limit of 0.1 ng/ml of the antibodies. Anionic and zwitterionic bilayer membranes from di(tetradecyl)phosphate and phosphocholine derivatives, respectively, were less sensitive as detectors of the hapten-antibody reaction. Ionic interactions between cationic bilayer membranes and anionic haptens are important for successful assay performance.

Effects of systemic interleukin-1beta administration on daily drinking and renal excretory function in conscious rats.

To elucidate the roles of interleukin-1beta (IL-1beta), a cytokine with several diverse actions, in the control of body fluid balance, its effects on daily drinking behavior and renal excretory function were examined in conscious rats. Administration of IL-1beta (4 microg/kg, I.P.) resulted in the suppression of both daily drinking and food intake and a decrease in daily urinary sodium and potassium excretion, but had no effect on urine volume. The IL-1beta-induced decrease in sodium excretion was abolished in renal-denervated rats. Kainic acid was then injected into the anteroventral third ventricle region, including the organum vasculosum of the lamina terminalis, to examine whether neurons in this region are involved in the IL-1beta-induced responses; the effects on daily drinking and urinary sodium and potassium excretion were abolished, whereas the effects on food intake, although attenuated, were still present. In contrast, electrical lesion of the subfomical organ did not affect the IL-1beta-induced responses. Thus, IL-1beta seems exert its effects on body fluid balance at several distinct sites in the central nervous system.

Activity and stability of glucose oxidase in molecular films assembled alternately with polyions.

Anionic glucose oxidase (GOD) was assembled alternately with polycations, namely, poly(ethylenimine) (PEI) and poly(dimethyldiallyl-ammonium chloride) (PDDA), in the preparation of molecular films. Enzymatic activity of the films was investigated by sequential redox reaction with glucose, peroxidase (POD) and DA67 dye. The apparent activity was not influenced by substrate diffusion at up to 5 microg of immobilized GOD (at the area of 5 x 5 mm(2) x 2 faces). This is ascribed to the less dense packing of the alternate molecular film compared with Langmuir-Blodgett (LB) films. Immobilized GOD could be released into solution, and its activity was about 80% of native GOD, indicating that the immobilization did not cause significant denaturation. The enzyme activity of the GOD film was maintained for 14 weeks when stored in buffer and in air at 4 degrees C. Activity measurement after incubation at elevated temperatures showed that significant deactivation was not observed up to 50 degrees C. This shows that GOD in the film has higher thermostability than native GOD. The pH profile of the GOD activity in the film became broad and shifted towards higher pH than that of native GOD. The GOD film was also prepared by the premixing method, in which a GOD-polyion complex was assembled alternately with another oppositely-charged polyion. The enzyme activity of the alternate film obtained by premixing was much higher (maximal enhancement, 67-fold) than that of the conventionally assembled films. Better dispersion of GOD in the premixed film appears to enhance the enzyme activity.

[Multifactorial analysis of the pyuria after transurethral prostatectomy].

Multifactorial analysis on 395 patients revealed important factors which prolong the pyuria after transurethral prostatectomy. They were the age of the patient, anemia and leukocytosis before surgery. These are factors which relate with the defense mechanism of the patient. Local factors, such as the duration of indwelling urethral catheter, the size of the prostate or prostatic bed and preoperative infection, were not so important for prolonging the pyuria after transurethral prostatectomy. The time of the resection and weight of the prostate had an intimate relation each other, and the former was the more important factor. The use of antimicrobials probably controlled these local risk factors, thus making them unimportant in the prolongation of the pyuria after transurethral prostatectomy.

[Renal lymphoma. Report of 2 cases and review of the literature].

Two cases of renal lymphoma were reported. Case 1 was a 73-year-old, and case 2 was a 59-year-old female. Their chief complaint was flank pain. The findings obtained by CT and angiography were not compatible with renal cancer. The tentative diagnosis of case 1 was inflammatory disease or soft tissue tumor, and that of case 2 was renal subcapsular tumor. Histological specimen was obtained by open biopsy from case 1, and by nephrectomy from case 2. Immunohistochemical surface marker study revealed both tumors were B cell lymphoma. Chemotherapy (CHOP-Bleo, or PPA) in both cases and additional radiotherapy in case 2 markedly reduced the tumor size. Nevertheless, case 1 died 5 months later from recurrence, and case 2 died 14 months later of gastrointestinal bleeding. At autopsy, the renal subcapsular layer was infiltrated by lymphoma cells in both cases, and lymphadenopathy was not observed. Reviewing 16 cases previously reported as renal lymphoma, the capsular or subcapsular diffuse infiltration to the kidney is considered to be a characteristic feature of renal lymphoma.

Molecular Dispersion of Chains in the Mixed-Valence Complexes

A way to prepare molecular electronic wires in organic media is the solubilization of one-dimensional mixed-valence complexes with varied metal species through the formation of amphiphilic supramolecular assemblies (see picture). Dissociation and reassembly of the complex was detected as thermochromism in the intervalence (M(II)-->M(IV)) absorption bands.