[Effect of nicotine-administration on tyrosine hydroxylase-containing neuron in the rat forebrain; immunohistochemical study with semiquantitative morphometric analysis]

Nicotine is toxic substance that is absorbed by cigarette smoking and easily causes dependence. It is clear that smoking is bad for health, however, the effects of nicotine itself on the central nervous system have not been elucidated. We studied the effects of nicotine-administration (5 mg/kg x 2/day, 7 days) on immunoreactivity for tyrosine hydroxylase (TH), the rate-limiting enzyme of catecholamine synthesis, in the rat forebrain including the cerebral cortex, hippocampus, striatum and hypothalamus to investigate the influence on catecholaminergic neurons. In the nicotine-administration group, both the number and intensity of TH-immunoreactive fibers and terminals increased in the fronto-parietal cortex, anterior cingulate cortex and hippocampus in comparison with those of the control group, and a significant difference was demonstrated by computer assisted morphometric analysis. These findings suggest that nicotine-administration influences catecholaminergic neural systems in the forebrain, especially in the cerebral cortex and hippocampus and that these effects might be related to developing the dependence on smoking.

Mutational specificity of the ferrous ion in a supF gene of endonuclease III/VIII deficient Escherichia coli

When 125 microM Fe2+/EDTA treated plasmid pUB3 was used to transfect an Escherichia coli NKJ2004 (nth nei) host, which is totally defective in glycosylases for thymine glycol and 5-hydroxycytosine, a 3.7 fold increase in mutation frequency was observed. Among 46 supF mutants sequenced, 28 had base substitutions, with G:C-->C:G transversion predominant (14 cases), followed by G:C-->T:A transversion (6 cases) and G:C-->A:T transition (6 cases). The results are consistent with our previous Fe2+ mutagenesis results where, in the wild type host, 78% were base substitutions, with G:C-->C:G transversion (59%) predominant, followed by G:C-->T:A transversion (28%) and G:C-->A:T transition (11%). Treatment of pUB3 DNA with Fe2+/EDTA did not yield formation of Endonuclease III sensitive sites. The possibility of 5-hydroxycytosine as the causative lesion for Fe2+ induced G:C-->C:G transversion is discussed.

Synthesis and imaging of blood-brain-barrier permeable nitroxyl-probes for free radical reactions in brain of living mice

Three different lipophilic nitroxyl-probes having capability to pass the blood-brain barrier were, for the first time, synthesized to estimate free radical reactions in brain of living animals. Two of the three were designed to be hydrolyzed by esterase and remain in cell. All 3 probes had high n-octanol/buffer partition coefficients and gave 2 signal components in in vivo ESR spectra at head of living mice after intravenous injection. The ESR parameters of 2 components agreed with those of probes dissolved in water and lipidic phases. ESR-CT imaging on the nitroxyl-proves after intravenous injection revealed that all probes presented in both encephalon and extracranial region of head. Tissue distribution of the nitroxyl-probes demonstrated that the newly synthesized lipophilic nitroxyl-probes had capability to pass the blood-brain barrier and accumulated in brain than that of hydrophilic probe.

Cellular effect of thermal neutron capture treatment using 10B1-para-boronophenylalanine: lethal effect on melanoma cells with different degrees of X-ray sensitivity

We studied the effect of neutron capture treatment using 10B-compound on X-ray sensitive P-39 and X-ray resistant G-361 human melanoma cell lines, and found a high lethal effect of boron neutron capture therapy in comparison with conventional ionizing radiation. The P-39 line was sensitive to thermal neutron radiation, and extremely sensitive to bleomycin treatment, whereas the G-361 line was resistant to both forms of treatment; however, the two cell lines had similar sensitivity to thermal neutron radiation after pretreatment with 10B1-para-boronophenylalanine (10B1-BPA, 200 micrograms/ml medium). These results show that the thermal neutron capture products (a 7Li nucleus and alpha particle) are highly damaging and short range in tumor cells and thus more efficiently inactivate melanoma cells irrespective of x-ray sensitivity, than conventional X-ray-irradiation.

Free radicals from 1-palmitoyl-2-arachidonoylphosphatidylcholine liposomes in Fe2+/ascorbic acid solution

The generation of free radicals during the lipid peroxidation of liposomes composed of 1-palmitoyl-2-arachidonoylphosphatidylcholine (PAPC-liposome) in Fe2+/ascorbic acid (AsA) solution was studied by the ESR spin trapping technique. A carbon-centered radical adduct was observed using alpha-(4-pyridyl-1-oxide)-N-tert-butyl-nitorone (4-POBN) and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), but no oxygen-centered radicals such as .OH, LO., and LOO. were observed. The lipid peroxidation evaluated as 2-thiobarbituric acid reactive substances was inhibited by the addition of 4-POBN. The intensity of this inhibitory effect was dependent on the time when 4-POBN was added to the mixture of PAPC-liposomes and Fe2+/AsA solution, and no inhibitory effect could be observed after 4 min. The signal intensity of the carbon-centered radical adduct was dependent on the lipid concentration of PAPC-liposomes. These results suggest that the alkyl radicals generated from PAPC-liposome peroxidation induced by Fe2+/AsA were trapped by DMPO or 4-POBN at an earlier stage of lipid peroxidation.

In vivo ESR studies on pharmacokinetics and metabolism of parenteral lipid emulsion in living mice

PURPOSE

We applied non-invasive and real-time method with in vivo ESR spectroscopy to determining pharmacokinetics and metabolism of lipid emulsion as a drug carrier in living mice.

METHODS

A spin-labeled triglyceride (SL-TG) was newly synthesized and lipid emulsion containing SL-TG was prepared. In vivo ESR spectra in mice were observed after intravenous administration of the lipid emulsion.

RESULTS

In vivo ESR spectra consisted of three components, coinciding with the in vitro spectra of SL-TG particles, free and immobilized fatty acids. The amount of the components depended on both the observing domain and the period after administration. In the chest, all three components were observed, while SL-TG particle was lacking in the abdomen. The half-life of the lipid particles in the chest was 2 hr.

CONCLUSIONS

Non-invasive and real-time analysis of drug carriers in living animal is successfully accomplished using an in vivo ESR method.

In vivo detection of mouse liver nitric oxide generation by spin trapping electron paramagnetic resonance spectroscopy

Nitric oxide, a paramagnetic molecule synthesized in biological systems, plays an important role in many pathophysiological processes. In vivo electron paramagnetic resonance spectroscopy/imaging could be a useful tool to study, in situ and in real time, nitric oxide generation. In this study the intracellular production of nitric oxide in tissues of living septic-shock mouse was detected by the spin trapping technique in combination with electron paramagnetic resonance spectroscopy. A lipophilic spin trap agent was used and nitric oxide formation was determined by the intensity of its iron-mononitrosyl complex. Among all examined tissues at 20 degrees C, the highest signal intensity of the trapped nitric oxide was found in the liver homogenates (n = 5). The amount of complex found in the kidneys was about 40% of that found in the liver. In the brain and lung, around 10% was found. This study reports, for the first time, the in vivo detection of nitric oxide generation in the upper abdomen of septic-shock mice (n = 3). Within 1 h after the trap injection, the signal was stable, indicating that the formation had reached a steady state.

Selective increase in astrocytic elements in the rat dentate gyrus after chronic toluene exposure studied by GFAP immunocytochemistry and electron microscopy

Using glial fibrillary acidic protein (GFAP) immunohistochemistry, and electron microscopy, we examined changes in the features of astrocytes in the dentate gyrus of the hippocampal formation after high-dose chronic toluene inhalation (2000 ppm, 4 h/day) for 1 month. In toluene-treated rats, the numbers of GFAP-immunoreactive (IR) astrocytes were not changed, whereas the area and intensity of GFAP-IR processes were increased markedly in the dentate gyrus. In addition, dense, thick and highly-stained GFAP-IR processes appeared entering into the granular cell layer, compared with those of controls. At the electron microscopic level, numerous astrocytic processes with high electron density intervened between the granular cells. These results suggest that high-dose of chronic toluene exposure induces morphological changes in astrocytes in the dentate gyrus of the hippocampal formation.

Effect of chronic toluene exposure on tyrosine hydroxylase-positive nerve elements in the rat forebrain: an immunohistochemical study combined with semiquantitative morphometric analysis

The effects of chronic toluene exposure [3000 p.p.m. for 4 h (09:00-11:00, 13:00-15:00)] every day for 3 weeks on immunoreactivity for tyrosine hydroxylase (TH), the rate limiting enzyme of catecholamine synthesis, in the rat forebrain were studied. In toluene-exposed rats, increases in both number and intensity of TH-immunoreactive fibres and terminals were observed in most parts of the forebrain including the cerebral cortex, hippocampus, lateral septal nucleus and hypothalamus, compared with control rats. These findings suggest that chronic toluene exposure might influence catecholaminergic neural systems.

In vivo ESR measurements of free radical reactions in living mice

In vivo ESR measurements were carried out to estimate free radical reactions in living mice using nitroxyl radicals as probes. The ESR signal of nitroxyl radical which was intravenously or intramuscularly injected to living female ddY mice decreased gradually by reducing to the corresponding hydroxylamine. The reduction rate was enhanced by oxidative stress, and pre-treatment of antioxidants suppressed the enhancement of signal decay. Oral administration of carbon tetrachloride enhanced signal decay in upper abdomen but not in thorax. These results indicated that free radicals, which can reduce nitroxyl radical, were produced in the upper abdomen by oral administration of carbon tetrachloride.

Immunohistochemical alterations in neuropeptide Y-positive nerve elements in rat cerebral cortex following acute phencyclidine treatment

Phencyclidine (PCP) is a dissociative drug and has been known to be an antagonist of N-methyl-D-aspartate (NMDA) receptor. We examined possible effects of acute treatment with PCP on neuropeptide Y (NPY) immunoreactive nerve fibres and cell bodies in rat forebrain by immunocytochemistry combined with morphometric analysis. Following the treatment, significant alterations were observed throughout the cerebral cortex, compared with controls. NPY-positive perikarya were increased in number (178%) whereas NPY-positive fibres and terminals were decreased in area (38%). The result suggests that the cortical NPY neuronal system is controlled, at least partly, by glutamatergic inputs via NMDA receptor-mediated mechanisms.

[A 71-year-old woman with progressive gait disturbance and dementia]

We report a 71-year-old woman with progressive gait disturbance and dementia. The patient was well until 61 years of age (1980) when she noted a gradual onset of gait disturbance. A year later, she noted slurring of the speech and forgetfulness. In 1982, she noted difficulty in looking down and progression of her gait disturbance. In 1983, she became unable to walk alone unless supported. She was admitted to our service in 1984; neurological examination at that time revealed moderate dementia, limitation in the vertical gaze, slurred speech, and wide based ataxic gait. She was discharged for out patient follow up. Cranial CT scan in 1989 revealed cortical, brain stem, and cerebellar atrophies. On March 10, 1990, she fell down and hit her head. She developed headache on April 1, vomited on April 8, and was admitted to our service again. On admission, she was somnolent, she was unable to follow an object to any direction; oculocephalic response was elicited to horizontal directions, however, it was difficult to induce in the vertical direction. Rigidity was noted in the extremities except in the left lower extremity. Rapid alternating movement was difficult and dysmetria was noted in the finger-to nose test. Deep reflexes were exaggerated without clonus; the plantar response was extensor bilaterally. Cranial CT scan revealed bilateral subdural hematoma. She was treated with intravenous infusion of glycerol, and she became alert after this treatment; however, she was markedly demented. She was unable to walk alone. She was discharged to home, but she showed progressive loss of activities, and became bed ridden in December 1992. In January of 1993, she developed fever, dyspnea, and disturbance of consciousness, and was admitted again on January 26, 1993. On admission, her blood pressure was 70 mmHg by palpation and body temperature 38.5 degrees C. The lungs were clear. On neurologic examination, she was semicomatose; the optic fundi were unremarkable; only incomplete eye movements elicited by the oculocephalic reflex. She was passive supine in position; some spontaneous movements were observed in the extremities. Lead-pipe rigidity was noted in both upper extremities, but the muscle tone was decreased in the lower extremities. No abnormal involuntary movements were seen. Deep reflexes were exaggerated except for the ankle jerk which was diminished bilaterally. The plantar response was extensor on both sides.(ABSTRACT TRUNCATED AT 400 WORDS)

In vivo ESR studies of antioxidant activity on free radical reaction in living mice under oxidative stress

In vivo antioxidant activity seems to be quite complicate due to multiple interaction with biomaterials and differs from results by in vitro experiments. In vivo estimation of antioxidant activity is performed by measuring TBA reactive substances in blood or hydrocarbon gases in breath, but these systems do not measure free radical reaction but the final products of oxidative reaction. In the present study, we applied in vivo ESR to evaluate antioxidant activity by monitoring the redox reaction of nitroxide radical and clearly found that the nitroxide is very susceptible to oxidative stress in vivo and quite useful to evaluate antioxidant activity non-invasively.

A comparative ESR study of some paramagnetic materials as probes for the noninvasive measurement of dissolved oxygen in biological systems

The ESR properties of three types of paramagnetic material, active charcoal, fusinite and a stable nitroxide radical 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPONE), were examined in order to evaluate their suitability as probes to measure dissolved intra- and extra-cellular oxygen. Although, with changes in oxygen concentration, a greater change in the linewidth of ESR signals was observed with fusinite or active charcoal, it took a long time (15 min for active charcoal and more than 6 h for fusinite) for equilibrium to be achieved. On the other hand, equilibrium was reached very rapidly in the case of the TEMPONE spectra although the sensitivity to changes in oxygen concentration was only moderate. Furthermore, since lipid bilayers are permeable to TEMPONE, this compound can be used to measure intracellular oxygen concentration when employed in combination with membrane-impermeable spin-broadening reagents which act on ESR signals arising from extracellular probes. A perdeuterated derivative of TEMPONE is useful in that it gives a greater signal-to-noise ratio and greater sensitivity to changes in oxygen concentration. In conclusion, active charcoal is suitable as a probe for extracellular oxygen in a system where changes are slow, while nitroxide is a versatile probe for measuring rapidly changing intra- and extra-cellular oxygen concentrations.

Inhibitors of poly (ADP-ribose) synthesis inhibit the two types of repair of potentially lethal damage

PURPOSE

The purpose of this study was to examine whether 3-amino-benzamide (3ABA), an inhibitor of poly (ADP-ribose) synthesis, inhibits the two types of potentially lethal damage (PLD) repair, termed slow and fast.

METHODS AND MATERIALS

The fast-type PLD repair was measured by the decrease in survival of V79 Chinese hamster cells by postirradiation treatment with 3ABA. The slow-type PLD repair was measured by the increase in survival by posttreatment with conditioned medium (CM), which became conditioned by growing a crowed culture of cells and supports the slow-type PLD repair.

RESULTS

Up to 1 mM, 3-ABA inhibited the slow type repair; at doses of 2 mM and above, it inhibited the fast type of PLD repair.

CONCLUSION

There are quantitative differences in cellular effects of 3ABA dependent on concentration. Poly (ADP-ribose) appears to play an important role in the PLD repairs and has little effect on the repair of sublethal damages.

Highly polarized expression of carbohydrate-binding protein p33/41 (annexin IV) on the apical plasma membrane of epithelial cells in renal proximal tubules

p33/41 is a Ca(2+)-dependent carbohydrate-binding protein and is identical to annexin IV, a member of the annexin protein family. The localization of p33/41 in bovine kidney specimens was investigated immunohistochemically by use of specific polyclonal antibodies. The most interesting finding on immunostaining was that p33/41 was highly concentrated in the apical plasma membrane of the epithelial cells in the proximal tubules contrary to the distribution throughout the cytoplasm in the papillary ducts and papilla epithelium. The enrichment of p33/41 in the apical membrane was confirmed by immunoblotting of the brush border membrane fraction prepared from a kidney homogenate. Sequential extraction with EDTA and Triton X-100, and a partition experiment with Triton X-114 revealed that most p33/41 associates with the renal brush border membrane in a Ca(2+)-independent manner and is integrated into the membrane like intrinsic membrane proteins.

[Difference of thallium-201 kinetics between VX-2 tumors and inflammatory lesions in rabbits]

To evaluate the difference of thallium-201 chloride (201Tl) kinetics between malignant tumors and inflammatory lesions, 201Tl scintigraphy was performed in the 30 rabbits with variable sized VX-2 tumors; and in the 27 rabbits with variable sized inflammatory lesions induced by turpentine oil and the solution of auto-feces. The degree of 201Tl uptake was expressed as the count ratios of the lesions over the contralateral normal muscle tissue, and the early uptake ratio (1 min after the injection) and the delayed uptake ratio (30 min) were acquired. The retention index derived from these ratios was used to assess the degree of 201Tl washout from the lesions. When dividing both the tumors and inflammatory lesions into the large lesions (more than 40 mm in diameter) and smaller ones, different 201Tl kinetics according to the size of the lesions were demonstrated. In the small lesions, the VX-2 tumors showed higher early and delayed uptake ratios and a faster washout than the inflammatory lesions. In contrast, in the large lesions, both the early and delayed uptake ratios were not significantly different; however, the retention index in the tumors was higher compared to the inflammatory lesions. Thus, our animal study indicates that 201Tl kinetics are different according to the size of the tumor and inflammatory lesions, and that in the small lesions the higher tumor uptake compared to the inflammatory lesions may be available to differentiate. However, in the large sized lesions, assessment of the 201Tl washout from the lesions is necessary for differentiation.

Hyperthermic enhancement of cytotoxicity and increased uptake of cis-diamminedichloroplatinum(II) in cultured human esophageal cancer cells

Thermal enhancement of cytotoxicity of cis-diamminedichloroplatinum(II) (CDDP) has been well recognized and applied clinically to chemotherapy of various malignancies, but its fundamental mechanism remains to be elucidated. In order to obtain a clue to this mechanism, we analyzed the effect of hyperthermia on the uptake and subsequent distribution of [195mPt]CDDP in two lines of esophageal cancer cells (KYSE-150 and KYSE-170) established from clinical patients. First, we observed a significant increase in [195mPt]CDDP uptake by both types of cells at increasingly higher temperatures. The incorporated CDDP was distributed between the nucleus and the cytosol at a ratio of approximately 3:1, and the ratio remained the same at various temperatures. The CDDP was found in all four molecular fractions, i.e., DNA, RNA, protein, and TCA-soluble, with a slight preference for DNA at higher temperatures. Enhancement of cytotoxicity required simultaneous, and not sequential, treatments with CDDP and hyperthermia; hyperthermia after CDDP treatment increased the efflux of CDDP from the cells, and rather reduced the cytotoxicity of CDDP. These results suggest that thermal enhancement of the cytotoxicity of CDDP is caused mainly by acceleration of the drug entry into the cell, probably due to increased permeability, and a consequent increase in the amount of CDDP binding to DNA. This mechanism gives support for clinical trial of simultaneous treatment with CDDP and hyperthermia.

Aging retards spin clearance from mouse brain and food restriction prevents its age-dependent retardation

After the nitroxyl radical 3-carbamoyl-2,2,5,5-tetramethyl-1-pyrrolidinyloxyl (carbamoylPROXYL) was intraperitoneally administered to mice, the time courses of changes in the intensity of signals in L-band electron spin resonance spectra from their brains were measured. The spin clearance rate of old, ad libitum-fed mice was lower than that of young, ad libitum-fed mice. The rate of old, food-restricted mice was significantly higher than that of old, ad libitum-fed mice and was comparable to that of young, ad libitum-fed mice. The spin clearance was found to be due to the one-electron reduction of the nitroxyl radical, because a decreased spin intensity of it in serum was restored to the original level by potassium hexacyanoferrate (III) oxidation in vitro. These results suggest that reducing capacity in the cardiovascular system of mice is decreased with advancing age, and that food restriction prevents an age-dependent decrease in the reducing capacity.

Antioxidant activity of nitroxide radicals in lipid peroxidation of rat liver microsomes

Inhibition of lipid peroxidation by nitroxide radicals in rat liver microsomes was studied using several nitroxide compounds which have various lipophilicities. Addition of NADPH to microsomes in an oxygen atmosphere induced lipid peroxidation as indicated by the increase of thiobarbituric acid (TBA)-reactive substances, hydroperoxide, conjugated diene, and oxygen consumption. Lipid peroxidation was inhibited by nitroxides located in both water phase and membrane. Oxygen consumption and the generation of active oxygens were inhibited by water-soluble nitroxides but not by intramembranous ones. Intramembranous nitroxides significantly prevented the production of conjugated dienes and lipid hydroperoxides. The facts suggest that water-soluble nitroxides interfere with the generation of active oxygens as preventive antioxidants, while intramembranous nitroxides inhibit the formation of lipid alkyl radical as chain-breaking antioxidants. The intensity of ESR signals due to intramembranous nitroxide radicals remained constant during the inhibition reaction of lipid peroxidation, suggesting that the prevention of lipid peroxidation is coupled with the reversible redox reaction between nitroxides and the reduced nitroxides in microsomes. The reduced forms of nitroxides, which were prepared by the reduction of intramembranous nitroxides, also inhibited the generation of TBA-reactive substances as well as the parent nitroxide. These facts indicate that either intramembranous nitroxide radicals or their reduced forms, "hydroxylamines," may be useful lipophilic antioxidants.

[Usefulness of 201TlCl SPECT for evaluation of treatment effect of pancreatic cancer]

To assess the treatment effect of pancreatic cancer, thallium 201 chloride (201TlCl) SPECT was performed in three patients. All of the patients before and after treatment showed the same change between the tumor/liver uptake ratio of 201TlCl and the serum level of CA 19-9. In one of the patients, tumor shrinkage was not observed on CT. However, the uptake ratio decreased, accompanying with a reduced serum level of CA 19-9. These results indicate that 201TlCl SPECT is useful to evaluate therapeutic effect of pancreatic cancer.