Co-synthesis and Electrochemical Investigation of the Nitrogen-Doped Carbon Layer with Metallic Nano Beads on the SiOx Anode for Lithium Secondary Batteries

The high theoretical capacity (∼2000 mAh g-1) of silicon suboxide (SiOx, with 1 < x < 2) can solve the energy density issue of the graphite anode in Li-ion batteries. In addition, it has an advantage in terms of volume expansion or side reactions compared to pure Si or Li metals, which are considered as next-generation anode materials. However, the loading content of SiOx is limited in commercial anodes because of its low cycle stability and initial coulombic efficiency. In this study, a nitrogen-doped carbon layer with Cu beads (N-C/Cu) derived from copper phthalocyanine (CuPc) is applied to a SiOx electrode to improve its electrochemical performance. The SiOx electrode is simultaneously coated with a Cu- and N-doped carbon layer using CuPc. N-C/Cu synergistically enhances the electric conductivity of the electrode, thus improving its electrochemical performance. The SiOx/N-C/Cu composite has better cyclability and higher capacity (1095.5 mAh g-1) than the uncoated electrode, even after 200 cycles in the 0.5 C condition. In full-cell cycling with NCM811 cathodes, the SiOx (60 wt % of SiOx, with a n/p ratio of 1.1) and graphite-mixed (7.8 wt % of SiOx, with a n/p ratio of 1.1) anodes also show improved electrochemical performances in the same conditions.

Population-based, three-dimensional analysis of age- and sex-related femur shaft geometry differences

This study deals with differences of femoral geometric focus on the bowing and width. Analysis using three-dimensional skeletonization showed increase of femoral bowing and femur width over life (more in women), and widening of the medullary canal only in women after 50 years old, not in men.

INTRODUCTION

The changes in femur geometry that occur with aging and lead to fragility or insufficiency fracture remain unclear. The role of the lower limb geometry, including the femur and femoral bowing, has become a point of discussion, especially in atypical femur fracture. This study aimed to analyze femur shaft geometry using three-dimensional skeletonization.

METHODS

We acquired computed tomography images of both femurs obtained. A total of 1400 age- and sex-stratified participants were enrolled and were divided into subgroups according to age (by decade) and sex. The computed tomography images were used to produce 3-dimensional samplings of anatomical elements of the human femur using reconstruction and parametrization from these datasets. The process of skeletonization was conducted to obtain compact representation of the femur. With the skeletonization, we were able to compare all parameters according to age and sex.

RESULTS

The femur length was 424.4 ± 28.6 mm and was longer in men (P < 0.001). The minimum diameter of the medullary canal was 8.9 ± 2.0 mm. The radius of curvature (ROC) was 906.9 ± 193.3 mm. Men had a larger femur length, femur outer diameter, and the narrowest medullary diameter (P < 0.001, respectively). Women had significantly smaller ROC (P < 0.001). ROC decreased by 19.4% in men and 23.6% in women between the ages of 20 to 89 years. Femur width increased over life by 11.4% in men and 24.5% in women. Between the ages of 50 and 89 years, the medullary canal appears to have increased by 32.7% in women.

CONCLUSION

This geometry analysis demonstrated that femoral bowing and femoral width increased related to aging, and that the medullary canal widened after the age of 50 years in women. This cross-sectional study revealed important age- and sex-related differences in femur shaft geometry that occur with aging.

Dorsal intercalated segmental instability associated with malunion of a reconstructed scaphoid

We analysed scaphoid deformity as a result of surgical treatment of scaphoid fracture nonunion and assessed the deformity associated with a dorsal intercalated segmental instability pattern of carpal malalignment. A total of 45 patients who were treated for scaphoid fracture nonunion were included in the study. The height-to-length ratio of the scaphoid was measured on computed tomographic images and used to assess scaphoid deformity. Carpal malalignment was quantified based on the radio-lunate angle. A correlation analysis between the height-to-length ratio and the radio-lunate angle was performed. Dorsal intercalated segmental instability was defined as a radio-lunate angle >15°, and a receiver operating curve analysis was used to calculate the cutoff height-to-length ratio that can be accompanied with dorsal intercalated segmental instability. Extension of the lunate increases in proportion to the flexion deformity of the scaphoid; dorsal intercalated segmental instability can occur if the height-to-length ratio of the scaphoid is >0.73.

LEVEL OF EVIDENCE

IV.

Long-term results of simple hemiresection arthroplasty in the rheumatoid distal radio-ulnar joint

We retrospectively studied the radiological and clinical results of a simple hemiresection arthroplasty, a modification of previous oblique distal ulnar resections, in 62 patients with rheumatoid arthritis (68 wrists) over a mean follow-up of 103 (range 60-173) months. Fourteen wrists (20%) became fused at the radiocarpal joint and 28 wrists fused (41%) at the midcarpal joints during follow-up. Severe ulnar translocation of the carpus was observed in two wrists (3%), radio-ulnar convergence in five wrists (7%), as well as a significant decrease of carpal height ratio, without any radiological findings of stylocarpal impingement. Improvements in forearm pronation and supination, and reduction in pain were maintained at the last follow-up. Grip strength was not significantly improved. The Jebsen-Taylor hand function test showed improvements in writing, card turning, and simulated feeding. Fifty-two patients (58 wrists, 85%) were satisfied with the results at the last follow-up. Simple hemiresection arthroplasty showed good long-term results with few complications.

Phospho-ser 15-p53 translocates into mitochondria and interacts with Bcl-2 and Bcl-xL in eugenol-induced apoptosis

Our previous studies demonstrated that antiallergic effects of herbs such as clove and Magnoliae Flos (MF) resulted from the induction of apoptosis in mast cells. We here examined whether the antiallergic activity was caused by eugenol (4-allyl-2-methoxyphenol) which was one of major ingredients in the essential oils or extracts of numerous plants including clove and Magnoliae Flos. RBL-2H3 cells were treated with eugenol, and DNA electrophoresis, Western blotting, immunocytochemistry, confocal microscopy and immunoprecipitation were conducted. Effect of eugenol was tested using a rat anaphylaxis model. RBL-2H3 cells treated with eugenol showed typical apoptotic manifestations and translocation of p53 into mitochondria. Antisense p53 partially prevented the induction of apoptosis. Noticeably, we observed that p53 translocated into mitochondria was phosphorylated on ser 15. Phospho-ser 15-p53 physically interacted with Bcl-2 and Bcl-xL in mitochondria and its translocation into mitochondria preceded cytochrome c release and mitochondrial membrane potential (MMP) reduction. We also depicted that the survival of animals even after administration of the fatal dose of compound 48/80 might result from the decreased number of mast cells by eugenol pretreatment. In conclusion, eugenol induces apoptosis in mast cells via translocation of phospho-ser 15-p53 into mitochondria.

Pigment-lightening effect of N,N'-dilinoleylcystamine on human melanoma cells

BACKGROUND

Cystamine and linoleic acid have been reported to reduce melanin synthesis in vitro and in vivo. N,N'-dilinoleylcystamine (DLC) is a compound of cystamine and linoleic acid connected by an ester bond.

OBJECTIVES

To investigate the effects of DLC on melanin synthesis using cultured human melanoma cells.

METHODS

Levels of total melanin, eumelanin and phaeomelanin, tyrosinase protein and tyrosinase activity in situ were measured in HM3KO melanoma cells. Changes in degree of pigmentation were quantified by image analysis and compared with absorbance values. Tyrosinase from HM3KO cells was used to measure the direct effect of DLC on DOPA and DOPAchrome production.

RESULTS

At concentrations of 1.4-14 micromol L-1, DLC reduced the pigmentation of HM3KO melanoma cells but did not affect cell growth. The visual decrease in pigmentation produced by DLC was more dramatic than the decrease in total melanin content as measured by absorbance at 500 nm. DLC treatment decreased eumelanin synthesis and increased phaeomelanin synthesis in HM3KO melanoma cells. An in situ tyrosinase assay showed that DLC inhibited tyrosinase activity, as well as the level of tyrosinase protein.

CONCLUSIONS

These results suggest that DLC has pigment-lightening effects on HM3KO melanoma cells, produced by reducing the level of eumelanin while increasing the level of phaeomelanin.

Effect of phthalates on the stability and performance of AgBF4-PVP membranes for olefin/paraffin separation

The presence of a phthalate in dry polymer membranes consisting of polyvinylpyrrolidone (PVP) and AgBF4, AgBF4-PVP, provides long-term stability and better performance for the separation of propylene/propane gas mixtures.

Increased and correlated nuclear factor-kappa B and Ku autoantigen activities are associated with development of multidrug resistance

In this study, we investigated possible engagement of NF-kappaB and Ku autoantigen (Ku) activation in development of multidrug resistance (MDR) and circumvention of MDR by modulation of NF-kappaB and Ku. The NF-kappaB activity and NF-kappaB p65 subunit level were constitutively higher in MDR cells than in drug-sensitive parental cells. Interestingly, a faster running NF-kappaB DNA binding complex was identified as Ku, a DNA damage sensor and a key double strand break repair protein, and was positively correlated with the NF-kappaB activity in MDR cells and Ku- or both subunits of NF-kappaB-transfected cells. Also both NF-kappaB and Ku activities were activated or inhibited by treatment with etoposide (VP-16) or MG-132 (a proteasome inhibitor), respectively. Furthermore, PKA inhibitor suppressed markedly the constitutive and drug-induced activities of NF-kappaB and Ku in MDR cells and subsequently potentiated the cytotoxic activity of anticancer drugs. Our results proposed that the NF-kappaB and Ku activation could be one of multi-factorial MDR mechanism, and PKA inhibitor, likely via inhibition of NF-kappaB and Ku activities, could enhance the effectiveness of anticancer drugs against MDR cells with high activities of NF-kappaB and Ku.

A co-operative study: clinical characteristics of 334 Korean patients with moyamoya disease treated at neurosurgical institutes (1976-1994). The Korean Society for Cerebrovascular Disease

A co-operative study was conducted to determine the clinical characteristics of patients with moyamoya disease who were diagnosed and treated at neurosurgical institutes in Korea before 1995. Twenty-six hospitals contributed 505 cases and among them, the clinical characteristics of 334 patients with definite moyamoya disease were evaluated. The number of patients began to increase from the late 1980s, and after that approximately 20 patients were treated each year. There were two age peaks: from six to 15 and from 31 to 40 years of age. Haemorrhagic manifestations occurred in approximately 43% of the patients. The major clinical manifestations were haemorrhage in adults (62.4%) and ischaemia in children (61.2%). Overall 54.5% of the patients experienced decreased consciousness levels, mainly due to intracranial haemorrhage or cerebral infarction. In the patients with ischemic manifestations, the adult patients were more likely to have cerebral infarction than the pediatric patients (80% vs. 39%) and the pediatric patients were more likely to have TIA (61% vs. 25%). Thirty eight percent of the patients underwent bypass surgery and 53% of these procedures were performed bilaterally. Treatment policies, including indications for bypass surgery and commonly used drugs, were somewhat different according to the institution. Overall favorable outcome was 73%, and the most significant factor affecting poor outcome was haemorrhagic manifestation. This article describes the characteristics of 334 patients with moyamoya disease, who were diagnosed and treated at neurosurgical institutes in Korea before 1995.

Microbiological profile of a shipboard environment and the flora on contact lenses of seamen

PURPOSE

The purpose of this study was to culture and identify the spectrum of organisms (and their sensitivities) that contaminate the extended wear contact lenses of seamen in their working environment. A secondary aim was to identify the most appropriate first-line antibiotic regimen to be used on seamen who sustain contact lens-related corneal keratitis on board ship.

METHODS

Twenty pairs of contact lenses of 20 seamen in one group and 24 pairs in another group wearing contact lenses were collected at the end of 1 week of extended wear. Groups one and two differed only in the way lenses were stored prior to culturing. All contact lenses were then brought to the microbiological lab within 24 hours for culture and sensitivity testing.

RESULTS

The most common contaminants on the contact lenses in this study were Staphylococcus epidermidis and Staphylococcus aureus, organisms resident on the normal eyelids. Enterobacterand Pseudomonas species, present in a shipboard environment, were also identified as contaminants on the contact lenses. The organisms cultured from the contact lenses correlated well with those of normal lid flora as well as from the ship environment and are probably derived from these sources. Storage in saline-containing preservatives yielded significantly less positive bacterial cultures from the contact lenses in our study. All bacterial isolates were sensitive to ciprofloxacin whereas several bacteria resistant to cefazolin and gentamicin were identified.

CONCLUSION

The most common contaminants on the contact lenses in this study were Staphylococcus epidermidis and Staphylococcus aureus, organisms resident on the normal eyelids. Enterobacter and Pseudomonas species, which are normally present in a shipboard environment, were also identified as contaminants on the contact lenses. Ciprofloxacin is effective against all organisms identified as contaminants on the contact lenses in this study. Of all the antibiotics tested, it is probably the most suitable agent against contact lensrelated keratitis under such shipboard circumstances and is thus recommended in these situations.

Suppression of inducible nitric oxide synthase expression in RAW 264. 7 macrophages by two beta-carboline alkaloids extracted from Melia azedarach

We investigated the mechanism of suppression of inducible nitric oxide synthase (iNOS) by two beta-carboline alkaloids isolated from Melia azedarach, 4,8-dimethoxy-1-vinyl-beta-carboline (compound 1, C-1) and 4-methoxy-1-vinyl-beta-carboline (compound 2, C-2). iNOS activity in a cell-free extract of lipopolysaccharide/interferon-gamma-stimulated RAW 264.7 cells was found to be markedly increased, and this increase was prevented by C-1 and C-2, accompanied by the parallel reduction in nitrite accumulation in culture medium. However, C-1 and C-2 had no further effect on the iNOS activity prepared from fully lipopolysaccharide/interferon-gamma-stimulated RAW 264.7 cells. Treatment with C-1 or C-2 decreased the levels of iNOS protein and mRNA in a concentration-dependent manner. In addition, prostaglandin E(2) production, cyclooxygenase-2 protein and DNA binding of nuclear factor-kappaB (NF-kappaB) in lipopolysaccharide-stimulated RAW 264.7 cells were reduced by these compounds. These results indicate that C-1 and C-2 primarily inhibit iNOS and cyclooxygenase-2 activities via the suppression of de novo synthesis of these two enzymes, and that the inhibition of iNOS expression may be associated with the inhibition of NF-kappaB activation. Taken together, the results suggest that suppression of iNOS and cyclooxygenase-2 induction by lipopolysaccharide is responsible for the anti-inflammatory activity of these alkaloids through selective inhibition of the expression of genes, which play important roles in inflammatory signaling pathways.

Primary Sjögren's syndrome manifested as multiple sclerosis and cutaneous erythematous lesions: a case report

Sjögren's syndrome is a chronic autoimmune disorder characterized by lymphocytic infiltration of the lacrimal and salivary glands, leading to dryness of eyes (kerato-conjunctivitis sicca) and mouth (xerostomia). The skin lesions in Sjögren's syndrome are usually manifested as xeroderma, but sometimes appear as annular erythema or vasculitis. Central nervous system symptoms may be presented as one of extraglandular manifestations, though rare in incidence, and need differential diagnosis from multiple sclerosis. We report a case of a 45-year-old woman diagnosed as multiple sclerosis at first but later as neurologic manifestation of primary Sjögren's syndrome, showing signs of multiple sclerosis and cutaneous erythematous lesions.

Influences of dietary uptake and reactive sulfides on metal bioavailability from aquatic sediments

Understanding how animals are exposed to the large repository of metal pollutants in aquatic sediments is complicated and is important in regulatory decisions. Experiments with four types of invertebrates showed that feeding behavior and dietary uptake control bioaccumulation of cadmium, silver, nickel, and zinc. Metal concentrations in animal tissue correlated with metal concentrations extracted from sediments, but not with metal in porewater, across a range of reactive sulfide concentrations, from 0.5 to 30 micromoles per gram. These results contradict the notion that metal bioavailability in sediments is controlled by geochemical equilibration of metals between porewater and reactive sulfides, a proposed basis for regulatory criteria for metals.

Inducible nitric oxide synthase inhibitors from Melia azedarach var. japonica

In bioassay-guided search for inducible nitric oxide synthase (iNOS) inhibitory compounds from higher plants of South Korea, two beta-carboline alkaloids, 4-methoxy-1-vinyl-beta-carboline (1) and 4,8-dimethoxy-l-vinyl-beta-carboline (2) have been isolated from the cortex of Melia azedarach var. japonica. The structures of these compounds were elucidated on the basis of spectroscopic data. Compounds 1 and 2 showed marked inhibitory activity of iNOS on LPS- and interferon-gamma-stimulated RAW 264.7 cells.

Cloning and characterization of rat pancreatic beta-cell/liver type glucose transporter gene: a unique exon/intron organization

Four overlapping lambda genomic clones encoding rat pancreatic beta-cell/liver type glucose transporter (GLUT2) have been isolated and characterized. The gene is about 35 kb long and contains 14 exons and 13 introns. Contrary to the exon 1 of the human or mouse counterpart, the rat GLUT2 gene has three additional noncoding exons which were identified by 5'-RACE and all four were designated exon 1a, 1b, 1c, and 1d. The intron sequences bordering the splice site junctions generally follow the GT/AG rule except for one intron which begins with GC. The exon sequences determined from genomic DNA sequencing showed some differences when compared to the published rat GLUT2 cDNA. Transcription initiation site was determined by primer extension and located 661 bp upstream of the ATG translation initiation codon. Several potential binding sites for transcription factors such as C/EBP, Sp1, AP1, HNF-5, and UPE were observed and they may be responsible for the regulation of GLUT2 gene expression. The promoter region of rat GLUT2 showed little homology when compared with those of human or mouse. However, striking sequence identity (84%) was found when the adjacent intron regions flanking exon 1c were compared with the -970/-721 region of the mouse GLUT2 promoter. A series of deleted mutant constructs of the putative promoter region linked to the CAT reporter gene showed promoter activity in the primary hepatocyte culture. The region containing -4542/+240 showed the highest CAT activity and further deletion of the region showed gradual decrease in CAT activity.

Cloning and expression of rat liver type glucose transporter and translocation by insulin in Chinese hamster ovary cells

The 5'- and 3'-side half of liver type glucose transporter (GLUT2) cDNA was amplified from total RNA or mRNA by reverse transcriptase-polymerase chain reaction (RT-PCR). The amplified 5'-side fragment of GLUT2 cDNA was inserted into pGEM4Z and named pGLGT1, and the 3'-side fragment of GLUT2 cDNA was inserted into the HindIII site of pGLGT1 to construct pGLGT2 which contains an entire open reading frame of GLUT2 cDNA. The GLUT2 cDNA in pGLGT2 was transferred to an eukaryotic expression vector (pMAM) to construct pMLGT, which was expressed in the insulin-sensitive Chinese hamster ovary (CHO) cells. Western blot analysis showed that the GLUT2 gene in pMLGT was expressed in the transfected CHO cells successfully. The GLUT2 content in the plasma membrane fraction of insulin-treated CHO cells expressing GLUT2 increased 3.8-fold compared to that of the control group. This result suggests that GLUT2, which is not subjected to translocation by insulin in the cells of its major distribution, can be translocated if it is expressed in the suitable cells sensitive to insulin action.

Partial purification and identification of an immunosuppressive factor in AIDS sera

The cause of the profound immunodeficiency state induced by the human immunodeficiency virus (HIV) is not yet fully understood. Although direct cytopathic effects of the virus leading to the loss of CD4+ lymphocytes are believed to play a major role, soluble factors that cause lymphocyte dysfunction have also been identified. Here, we demonstrate that sera of AIDS patients contain a viral component capable of profoundly inhibiting normal T lymphocyte and natural killer cell functions. This factor (M(r) 30,000-50,000) is relatively resistant to proteolytic degradation, heat denaturation, extreme pH, and chemical modifications. It has been determined by Western blotting to share epitopes with the gp41 viral transmembrane component of HIV-1. This immunosuppressive factor has the characteristic property of inhibiting lymphocyte activation in the early stage (within 3 hr) of mitogenic stimulation. Concomitant with the inhibition of lymphocyte activation and interleukin 2 (IL-2) production, transcription of the IL-2 message is also reduced in a time-dependent manner. The unique time dependency of this immunosuppressive factor in lymphocyte activation could serve as a valuable tool to study the early steps of signal transduction in lymphocyte activation beyond membrane interaction.

Catalytic properties of recombinant octameric, hexadecameric, and heterologous cyanobacterial/bacterial ribulose- 1,5-bisphosphate carboxylase/oxygenase

The recent isolation of a catalytically competent recombinant octameric core of the hexadecameric ribulose-1,5-bisphosphate carboxylase/oxygenase from the cyanobacterium Anacystis nidulans (Synechococcus) (B. Lee and F. R. Tabita, 1990, Biochemistry 29, 9352-9357) has provided a useful system for examining the properties of this enzyme in the absence of small subunits. Unlike most sources of hexadecameric ribulose bisphosphate carboxylase, the nonactivated Anacystis holoenzyme was not inhibited markedly by preincubation with ribulose 1,5-bisphosphate. This was also true for the Anacystis octameric core and a heterologous recombinant enzyme that comprised large subunits from Anacystis and small subunits from the bacterium Alcaligenes eutrophus, suggesting that substrate-mediated inactivation is not influenced by small subunits. In addition, the CO2/O2 specificity factor was not affected by the source of the small subunits incorporated into the structure of the hexadecameric protein, in agreement with previous in vitro heterologous reconstitution studies. The activated octameric Anacystis enzyme, however, was significantly more sensitive to inhibition by the phosphorylated effector 6-phosphogluconate than were the hexadecameric Alcaligenes and Anacystis enzymes and the heterologous Anacystis-Alcaligenes hybrid.

Prostatectomy in a district hospital

In order to monitor the safety and efficacy of a new service for transurethral prostatectomy, an audit was performed, prospectively, over a period of 7.25 years. Of 304 prostatectomies performed, 91% were by transurethral prostatectomy. The proportion of patients with retention was 52%, 16% were uraemic and the incidence of carcinoma of the prostate was 21%. The operative mortality rate was 1.0%. An outline of the treatment policy and the data on complications and revision operations are presented. Comparisons are made with the experience of teaching centres and other district hospitals. Transurethral prostatectomy can be performed safely in the district general hospital and is a service which is essential to the smooth running of the surgical department.

Recent studies on the molecular biology and biochemistry of CO2 fixation in phototrophic bacteria

Rhodobacter sphaeroides was found to contain two clusters of chromosomally encoded CO2 fixation structural genes. Recent studies indicate that genes within each cluster are cotranscribed, suggesting that there is a single long transcript for each cluster. All of the genes have been sequenced, homologies noted, specific mutations obtained, and interesting upstream regulatory sequences found. Site-directed mutagenesis studies of the Anacystis rbcS has begun to provide information relative to RubisCO structure and function. In addition, RubisCO-negative strains of photosynthetic bacteria have been constructed to screen for altered RubisCO sequences.

The effect of a cystamine derivative, bis[2-(E-2-hexenoylamino)ethyl] disulfide, on rat platelet aggregation

Bis[2-(E-2-alkenoylamino)ethyl] disulfides (compds. I), synthesized from cystamine and 2-trans fatty acids, inhibited collagen-induced rat and rabbit platelet aggregation. The most potent compound was bis[2-(E-2-hexenoylamino)ethyl] disulfide (compd. I-1), and this compound suppressed thromboxane B2 formation from arachidonic acid in rat platelets. The results suggested that compd. I-1 has an inhibitory effect on cyclooxygenase.

Further studies on the pharmacological effect of the anti-inflammatory compound, bis[2-(E-2-octenoylamino)ethyl] disulfide

Further studies on the pharmacological effect of orally administered bis[2-(E-2-octenoyl-amino)ethyl] disulfide (compd. I-3) was examined by using several experimental models in vivo. Compound I-3 showed analgesic activity, inhibiting both acetic acid- and acetylcholine-induced writhings in mice. This compound also showed antipyretic activity against yeast-induced fever in rats, and significantly inhibited arachidonic acid-induced mortality in mice. However, it had no effect on serotonin-induced paw edema formation or platelet activating factor-acether-induced mortality in mice. The effects of compd. I-3 are suggested to be due to inhibition of prostaglandin biosynthesis.

Studies on pharmacological activation of human serum immunoglobulin G by chemical modification and active subfragments. VIII. Effect of carboxamide-methylated light chain (Fr.I-L) on leukocyte functions

Human serum immunoglobulin G light chain (Fr.I-L), which was reduced and carboxamide-methylated, showed no effect on formyl-methionyl-leucyl-phenylalanine (FMLP)-induced chemotaxis nor on phagocytosis of yeasts when directly added to guinea pig polymorphonuclear leukocytes (PMNs). However, intravenously administered Fr.I-L inhibited emigration of leukocytes into the peritoneal cavity and promoted phagocytosis of yeasts in a yeast-induced peritonitis model in mice. Moreover, Fr.I-L reduced FMLP-induced chemiluminescence (CL) from PMNs. These facts indicated that the anti-inflammatory action of Fr.I-L was caused by inhibiting emigration of leukocytes into the injured site and scavenging superoxide radicals from the cells.

Excitation of visual cortex neurons by local intracortical microstimulation

The threshold current required for the excitation of visual cortex neurons in the vicinity (approximately 1 mm) of an intracortical stimulating electrode was measured as a function of the stimulus pulse duration in the anesthetized cat. For cortical neurons with latencies of activation from 0.4 to 3.4 ms and for stimulus pulse durations from 0.02 to 0.7 ms, the threshold current for all neurons tested decreased in an exponential fashion as the pulse width was increased. Rheobase current values (ampere-threshold) were 1.2 to 516 muA (mean 160 +/- 24 muA, N = 24) and chronaxie values were 0.07 to 0.79 ms (mean 0.217 +/- 0.036 ms, N = 24). When the quantity of charge required for neuronal excitation was calculated, a quasilinear relationship was found between threshold charge and stimulus pulse width. The minimum threshold charge (coulomb-threshold) occurred for the briefest pulse widths tested and were 2 to 86 nC (mean 36.4 +/- 4.4 nC, N = 24). When the pulse energy index was calculated (threshold current squared multiplied by the pulse width), the minimum pulse energy capable of generating an evoked response (a single action potential) occurred when the pulse width was approximately 80% greater than the chronaxie. These studies demonstrate that the predictions derived from A. V. Hill's classical theory of nerve excitation are to a first approximation obeyed by visual cortex neurons. For the three parameters analyzed as a function of stimulus pulse width, the pulse current is minimized at long pulse durations, the pulse charge is minimized at short pulse durations, and the pulse energy is minimized at pulse widths of intermediate value.