Dynamic changes of cathepsins B and L expression in the monkey hippocampus after transient ischemia

Enzymatic activities, expressions, and the immunohistochemical localization of lysosomal cystein proteases, cathepsins B and L, were analyzed in the monkey hippocampus after transient ischemia to clarify the mechanism of delayed cornu Ammonis (CA)-1 neuronal death. By enzymatic assay, the activity of cathepsin B increased in CA-1, 24 h after the ischemic insult, while that of cathepsin L decreased. On Western blotting, the protein contents of both cathepsins B and L increased immediately after ischemia. By immunohistochemistry, cathepsins B and L were stained as coarse granules in the perikarya of control CA-1 neurons, but in postischemic CA-1 neurons they were released from lysosome granules. In contrast, in CA-2 and the remaining sectors, enzymatic activities increased after ischemia, and immunoreactivities of cathepsins B and L increased only within lysosome granules. These results suggest that cathepsins B and L may play an important role in the breakdown of certain cell proteins in the postischemic CA-1 neurons.

Correction of background noise in direct digital dental radiography

OBJECTIVES

To clarify the source of noise in direct digital intra-oral radiography with RVG-S (Trophy Radiologie, Vincennes, France) and to use these to develop a method for correction of background noise.

METHODS

Sensor temperature, image acquisition time and X-ray dose were independently analysed with the IPLab Spectrum (Signal Analytics, Vienna, VA) software.

RESULTS

The decrease in pixel value due to the dark current was linearly related to the image acquisition time. Although a variation in sensitivity was observed when the sensor was exposed to X-rays, the mean pixel value of the entire image was linearly related to the exposure time. The image showing only the signal due to X-ray dose was derived from the original RVG-S image by correcting for the dark current and the pixel-by-pixel sensitivity variation of the CCD sensor.

CONCLUSION

The image formed only by X-ray dose distribution can be derived by correcting for the background noise.

Interventional radiology for the non-surgical removal of sialoliths

OBJECTIVES

To clarify the usefulness and limitations of interventional radiology for sialolithiasis.

METHODS

Sixteen patients (5 with parotid and 11 with submandibular sialolithiasis) were treated with a stone retrieval catheter (Dormia basket) under fluoroscopy. Digital subtraction sialography (DSS) and direct digital dental imaging (RVG) were performed in addition for 11 of the cases (DSS for 7 and RVG for 4 cases).

RESULTS

The sialolith was successfully removed in 10 cases. DSS and RVG were useful. Four cases failed because the stone was adherent to the ductal wall and two because the catheter could not reach the stone because of the ductal anatomy.

CONCLUSION

Interventional radiology is less invasive than surgical treatment and is the recommended first choice for treatment in the majority of cases of sialolithiasis.

Histological changes in rat embryonic blood cells as a possible mechanism for ventricular septal defects produced by an N-phenylimide herbicide

An N-phenylimide herbicide, S-53482, inhibits protoporphyrinogen oxidase, an enzyme common to chlorophyll and heme biosynthesis, and produces embryolethality, teratogenicity [mainly ventricular septal defects (VSD) and wavy ribs], and growth retardation in rats. In order to elucidate the mechanism of the developmental toxicity, in particular VSD, effects of the herbicide on rat embryonic blood cells were investigated histologically at the light and electron microscopic levels at 6, 12, 24, 36, and 48 h after oral administration of the chemical to pregnant rats on day 12 of gestation, the most sensitive day for toxicity. Electron and light microscopy demonstrated mitochondrial lesions, including abnormal iron deposits that were probably due to inhibition of heme biosynthesis, in erythroblasts derived from the yolk sac. Subsequently, degeneration of these erythroblasts occurred followed by erythrophagocytosis. Histologically hearts from exposed embryos had a thin ventricular wall, which may reflect a compensatory reaction to a loss of embryonic blood cells. Thus, the herbicide may induce VSD due to hematological dysfunction caused by the inhibition of heme biosynthesis rather than by direct injurious effects on the heart.

Definition of the mitogenic factor (MF) as a novel streptococcal superantigen that is different from streptococcal pyrogenic exotoxins A, B, and C

Human T cell activation by recombinant mitogenic factor (rMF) was investigated in comparison with that by recombinant streptococcal pyrogenic exotoxins (rSPE) A, B, and C. Recombinant MF, rSPEA, and rSPEC were mitogenic for peripheral blood mononuclear cells (PBMC), whereas rSPEB was not. Recombinant MF required only HLA-DR for the stimulation of PBMC, as determined using monoclonal antibodies (mAb) to HLA class II molecules and the mouse L cells transfected with HLA class II molecules. Recombinant SPEA and rSPEC required HLA-DR or HLA-DQ molecule. Recombinant MF selectively stimulated V beta 2, V beta 7, V beta 8, V beta 18 and V beta 21-bearing T cells, whereas rSPEA and rSPEC activated V beta 2 and V beta 6-bearing T cells as evaluated by the quantitative T cell receptor (TCR) analytical method. No clonality was observed in the nucleotide sequences of complementarity determining region 3 of TCR V beta in T cells responding to rMF. The profiles of cytokine production by PBMC in response to rMF, rSPEA, and rSPEC were quite similar. In summary, these results demonstrate that both HLA class II molecules and the TCR V beta required for rMF-mediated T cell activation are distinct from those required for rSPEA or rSPEC-mediated activation. Therefore, the MF is a novel streptococcal super-antigen which is different from SPEA, SPEB, and SPEC.

Regulation of neutrophil superoxide generation by alpha-tocopherol in human peripheral and umbilical-cord blood

OBJECTIVES

Alfa-tocopherol (VE) inhibits protein phosphorylation and affects protein kinase C (PKC)-dependent superoxide (O2) generation of phagocytic cells. Because umbilical-cord blood contains low concentrations of VE, we studied the effects of VE on stimulation-dependent O2 generation of neutrophils derived from the healthy human peripheral circulation (HPMNs) and the umbilical cord (UCBNs).

METHODS

O2- generation and VE content were assayed by reduction of ferricytochrome c and by HPLC with an electrochemical detector, respectively. Neutrophil-specific annexin protein was identified by an immunological method.

RESULTS

Both types of neutrophils generate significant amounts of PKC-dependent O2-generation, but weak PKC-independent O2-generation, except for opsonized zymosan-stimulated O2- generation in UCBNs. The VE content of UCBNs was similar to that of HPMNs although umbilical-cord blood contains a low concentration of VE. A neutrophil-specific annexin protein was also found in the UCBNs.

CONCLUSION

UCBNs have a greater ability to incorporate VE than HPMNs do, but have similar general characteristics of stimulation-dependent O2-generation to those of HPMNs.

The prognostic significance of vascular invasion by endometrial carcinoma

BACKGROUND

Recently, invasion of vascular spaces by endometrial carcinoma has received particular attention as a prognostic factor. The goal of the current investigation was to re-examine the effect of vascular invasion on tumor recurrence and survival in patients with endometrial carcinoma.

METHODS

Surgical specimens from 238 patients with endometrial carcinoma were examined for the presence of vascular invasion by tumor cells. Vascular invasion was compared with clinicopathologic features and postoperative survival. Survival curves by vascular invasion were evaluated by the Kaplan-Meier method.

RESULTS

In a histopathologic review of 238 cases of endometrial carcinoma, 82 neoplasms demonstrated vascular invasion. Vascular invasion significantly correlated with the extension of primary tumor, depth of myometrial invasion, and histologic grade. Patients with lymph node metastasis had a significantly higher incidence of vascular invasion. Survival at 5 years for patients with vascular invasion was 73.4%. This was significantly lower than the survival rate of 91.5% for women without this finding (P < 0.001). Among patients with lymph node metastasis, 80.2% of the patients with vascular invasion survived for 5 years compared with 95.3% of the patients without vascular invasion (P < 0.05). Ten of 47 patients with no lymph node metastasis but with vascular invasion developed recurrent carcinoma. Nine of these ten patients apparently had extrapelvic recurrences.

CONCLUSIONS

The presence of vascular invasion is a reliable prognostic indicator. Recording of tumor recurrence pattern may lead to a better selection of patients for adjuvant systemic therapy after surgery.

A new ultrasonic canal preparation system with electronic monitoring of file tip position

A new ultrasonic root canal preparation system has been developed that electronically monitors the location of the file tip during all instrumentation procedures. The Root ZX has been adapted for this purpose, and its filter circuit effectively cuts out the large spike noise of the ultrasonic unit. During enlargement of the canal, the ultrasonic vibration of the file can be stopped at any desired position on the meter. Extracted human tooth models with electronically measurable canals were used to test the device. Pre- and postoperative shapes of the root canals were evaluated using contact microradiography. The autostop mechanism worked correctly. Using a weak power and fine files, straightening, ledge formation, and file breakage were minimal. It seems that this system minimized the danger of overinstrumentation and could be safely applied in clinical practice.

Transient brain ischaemia provokes Ca2+, PIP2 and calpain responses prior to delayed neuronal death in monkeys

To clarify the mechanism of postischaemic delayed cornu Ammonis (CA)-1 neuronal death, we studied correlations among calpain activation and its subcellular localization, the immunoreactivity of phosphatidylinositol 4,5-bisphosphate (PIP2) and Ca2+ mobilization in the monkey hippocampus by two independent experimental approaches: in vivo transient brain ischaemia and in vitro hypoxia-hypoglycaemia of hippocampal acute slices. The CA-1 sector undergoing 20 min of ischaemia in vivo showed microscopically a small number of neuronal deaths on day 1 and almost global neuronal loss on day 5 after ischaemia. Immediately after ischaemia, CA-1 neurons ultrastructurally showed vacuolation and/or disruption of the lysosomes. Western blotting using antibodies against inactivated or activated mu-calpain demonstrated mu-calpain activation specifically in the CA-1 sector immediately after ischaemia. This finding was confirmed in the perikarya of CA-1 neurons by immunohistochemistry. CA-1 neurons on day 1 showed sustained activation of mu-calpain, and increased immunostaining for inactivated and activated forms of mu- and m-calpains and for PIP2. Activated mu-calpain and PIP2 were found to be localized at the vacuolated lysosomal membrane or endoplasmic reticulum and mitochondrial membrane respectively, by immunoelectron microscopy. Calcium imaging data using hippocampal acute slices showed that hypoxia-hypoglycaemia in vitro provoked intense Ca2+ mobilization with increased PIP2 immunostaining specifically in CA-1 neurons. These data suggest that transient brain ischaemia increases intracellular Ca2+ and PIP2 breakdown, which will activate calpain proteolytic activity. Therefore, we suggest that activated calpain at the lysosomal membrane, with the possible release of biodegrading enzyme, will cause postischaemic CA-1 neuronal death.

Oxygen-dependent reversible inhibition of mitochondrial respiration by nitric oxide

Effects of nitric oxide (NO) and NO generating agents, on the electron transport system of mitochondria were examined in a study of the mechanism and physiological importance of NO in energy metabolism. In the presence of various substrates, uncoupled respiration was inhibited by NO in manner which was both dose- and oxygen tension-dependent. Simultaneously measuring changes in cytochrome absorption spectra and respiration showed that the site of action of NO is cytochrome oxidase. Similar inhibition was also brought about by 1-hydroxy-2-oxo-3,3-bis(2-aminoethyl)-1-triazene (NOC 18), an NO donor. Electron paramagnetic resonance (EPR) analysis revealed that inhibition of uncoupled respiration occurred only during the presence of NO in the reaction mixture. The inhibitory effect of NO was increased significantly by lowering the concentration of mitochondrial protein. No appreciable inhibition of respiration was observed in the presence of 3-morpholinosydnonimine (SIN-1), a peroxynitrite anion (ONOO-) generating reagent, but inhibition did occur in the presence of superoxide dismutase (SOD). These results indicate that NO reversibly interacts with mitochondria at complex IV thereby inhibiting respiration particularly under physiologically low oxygen tension and that de novo generated ONOO may have no significant effect under the present experimental conditions.

Morphological changes in the triads and sarcoplasmic reticulum of rat slow and fast muscle fibres following denervation and immobilization

We observed the morphological features of the membrane systems (sarcoplasmic reticulum, transverse tubules and triads) involved with the excitation-contraction coupling in rat soleus and extensor digitorum longus muscle following two disuse protocols: denervation and immobilization. The immobilized positions were: maximum dorsal flexor (soleus were stretched and extensor digitorum longus were shortened), maximum plantar flexor (soleus were shortened and extensor digitorum longus were stretched), and midway between the dorsal flexor and plantar flexor. The arrangement of the membrane systems was disordered following both disuse conditions. Increases in transverse tubule network were apparent; there were clearly more triads than in normal fibres, and pentadic and heptadic structures (i.e., a close approximation of two or three transverse tubule elements with three or four elements of terminal cisternae of sarcoplasmic reticulum) were frequently appeared following both denervation and immobilization. The most notable difference between the influence of denervation and immobilization on the membrane systems is the time at which the pentads and heptads appeared. They appeared much earlier (1 week after denervation) in denervated than in immobilized (3 or 4 weeks after immobilization) muscle fibres. On the other hand, the frequency of pentads and heptads is clearly related to the fibre type (significantly higher in extensor digitorum longus) and to extent of atrophy. The different influences of immobilization in each leg position suggest that disuse, but with neurotrophic factor(s), influences on the membrane systems were affected by sarcomere length, and the neurotrophic factor(s) and muscle activity were not always necessary to form new membrane systems in disuse skeletal muscle fibres.

Oxamflatin: a novel compound which reverses malignant phenotype to normal one via induction of JunD

In the course of screening for inhibitors of tumorigenic phenotype of K-ras-transformed NIH3T3 cells (DT cells), we found a novel compound, oxamflatin, an aromatic sulfonamide hydroxamate derivative, which induces flat phenotype in these cells and suppresses their anchorage-independent growth. In contrast to DT cells, in v-raf-transformed NIH3T3 cells, no change in their morphology and no specific inhibition of their anchorage-independent growth was observed. Interestingly, oxamflatin was effective to NIH3T3 cells transformed by constitutively activated mutant of MEK, indicating the possibility that oncogene-induced morphological change is not necessarily induced by common signaling pathway such as MAP kinase cascade. In oxamflatin-treated DT cells, the expression of transcription factor junD was highly augmented, resulting in trans-activation of fibronectin gene by junD via cyclic AMP responsive element in its promoter. This behavior of junD was confirmed to correlate well with partial blocking of malignant phenotype in DT cells. Thus, oxamflatin can be categorized as the first reagent which induces genes whose products can interfere with oncogene-dependent transformation.

Two components of exocytosis and endocytosis in phaeochromocytoma cells studied using caged Ca2+ compounds

1. Changes in membrane capacitance evoked by the rapid photolysis of a caged Ca2+ compound, DM-nitrophen or nitrophenyl-EGTA, were investigated in undifferentiated PC12 cells. They were interpreted as representing exocytosis and endocytosis. 2. The Ca2+ jumps evoked two components of exocytosis. Slow exocytosis was selectively evoked with small increases in intracellular Ca2+ concentration between 5 and 10 microM, while fast exocytosis preceded the slow one at [Ca2+]i greater than 10 microM. 3. The release rates of the two components of exocytosis depended steeply on [Ca2+]i. A half-maximal release rate was achieved at 8 and 24 microM for the slow and fast exocytoses, respectively. 4. Prior Ca2+ rises did not augment the fast exocytosis. 5. The fast exocytosis was often followed by a rapid decrease in membrane capacitance, representing endocytosis, after a delay of 0.5-2 s. The speed and delay in the fast endocytosis were Ca2+ dependent. Amounts of the fast endocytosis tended to balance with those of the fast exocytosis evoked by the same Ca2+ jumps. 6. The slow exocytosis was followed by a sluggish endocytosis that was associated with large capacitance steps indicative of secretory processes involving large dense-core vesicles. The onset of the slow endocytosis exhibited a complex Ca2+ dependence. The amounts of the slow endocytosis appeared to parallel those of the slow exocytosis. Prior induction of the slow exocytosis gave rise to selective excess retrieval of membrane during the slow endocytosis. 7. These data indicate the existence of two distinct populations of secretory vesicles in PC12 cells. They seem to couple selectively with specific endocytotic mechanisms. Our data suggest that the two vesicles belong to two distinct secretory pathways.

New betaclamycin and aclarubicin analogs obtained by prolonged microbial conversion with an aclarubicin-negative mutant

Microbial conversion of beta-rhodomycinone and aklavinone using an aclarubicin-negative Streptomyces galilaeus mutant afforded new anthracycline antibiotics CG21-C and CG1-C which had a rednosyl-2-deoxyfucosyl-rhodosaminyl trisaccharide residue at C-7 of each added aglycone. They were produced only when a prolonged conversion culture took place. Because the usual conversion products containing a cinerulosyl-2-deoxyfucosyl-rhodosaminyl residue were at first accumulated and then decreased during further cultivation, it was evident that they occurred by the modification of terminal cinerulose. The isolation, purification, and structural determination are described, and cytotoxicity in vitro against cultured L1210 cells and the formation mechanism are discussed.

An application of electron paramagnetic resonance to evaluate nitric oxide and its quenchers

Electron paramagnetic resonance (EPR) spectrometry has been used for detection of free radicals, including nitric oxide (NO). The method was applied to evaluate if lazaroids, nonspecific scavengers of oxygen-derived free radicals, can reduce another radical species, namely, NO. When solutions containing 0 to 10 microM lazaroids (U78517F, U83836E, and U74500A) were mixed with NO (approximately 8.0 microM), and with a spin-trap agent specific to NO (10 microM carboxy-2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3 oxide, c-PTIO), the spectrum of NO-c-PTIO determined by the EPR decreased with increasing concentrations of lazaroids. An identical study with 1 to 1000 microM methylprednisolone or dexamethasone, which are prototypes of lazaroids, failed to reduce NO. In a separate study, rat red blood cells preloaded with U78517F were exposed to NO. EPR spectrometry demonstrated that hemoglobin in these cells were less nitrosylated compared with the cells not preloaded with U78517F. An ability of lazaroids to quench NO in vivo was evaluated by an intravenous injection of sodium nitrite (4 mumol/kg body weight) into rats pretreated with 10 mg/kg lazaroids (U78517F and U74500A). The nitrosylation of RBC hemoglobin was markedly attenuated in rats pretreated with lazaroids compared with those with vehicle. Thus, these lipophilic compounds protected cells from NO-induced nitrosylation both in vitro and in vivo. Lazaroids may be applicable as anti-NO agents.

Changes in granulocyte colony-stimulating factor concentration in patients with trauma and sepsis

OBJECTIVE

To better understand the role of granulocyte colony-stimulating factor (G-CSF) after the inflammatory response.

DESIGN

Serum G-CSF concentrations were measured serially in 19 trauma and 15 sepsis patients. Changes in G-CSF concentration were compared with those in the neutrophil ratio, phagocytic and bactericidal activities, and other cytokines.

MEASUREMENTS AND MAIN RESULTS

G-CSF concentrations in trauma patients were elevated on day 1, but quickly decreased within 7 days. G-CSF reached its maximum 3 hours after injury, parallel with peaks of interleukin-6 (IL-6) and IL-8, but not of tumor necrosis factor-alpha (TNF-alpha). In sepsis patients, G-CSF as well as TNF-alpha, IL-6, and IL-8 concentrations were markedly elevated at diagnosis and remained high during the course of the illness. These levels decreased significantly in the 11 survivors. Up to 3 days after the trauma, nonsegmented neutrophil ratios were higher than those thereafter. Neutrophil phagocytic and bactericidal activities remained normal during the course of disease in both conditions.

CONCLUSIONS

These results suggest that G-CSF plays an important role in the maturation and maintenance of function of neutrophils during the inflammatory response to trauma and sepsis.

Fast fluid-attenuated inversion recovery (FAST-FLAIR) of ischemic lesions in the brain: comparison with T2-weighted turbo SE

PURPOSE

We compared fast fluid-attenuated inversion recovery (FAST-FLAIR) images with Turbo SE T2-weighted images to evaluate the detectability of small ischemic lesions in the brain.

MATERIALS AND METHODS

Thirty-six cases of multiple cerebral ischemic lesions were examined with FAST-FLAIR and Turbo SE imaging. The detectability of lesions, ability to discriminate lesions from the cortex, visualization of perivascular space, and visualization of brainstem lesions were compared between the two sequences.

RESULTS

The total number of lesions detected on both sequences was 534 in 36 cases. Six lesions in three cases were detected only on FAST-FLAIR, and one lesion in one case was detected only on the Turbo SE. All the 52 lesions located close to the cortex could be discriminated from the cortex on the FAST-FLAIR images, while 23 of these lesions could not be discriminated on the Turbo SE. Perivascular spaces were not visualized as areas of high signal on the FAST-FLAIR images. Pontine lesions that were visualized in four cases were clearer on the Turbo SE images than on the FAST-FLAIR images.

CONCLUSION

The FAST-FLAIR images were shown to be useful in the detection of ischemic lesions and in distinguishing them from the surrounding normal structures. The FAST-FLAIR sequence is expected to become a new additional routine sequence.

Influences of sarcomere length and selective elimination of myosin filaments on the localization and orientation of triads in rat muscle fibres

Ultrastructural features of internal membrane systems directly concerned with the excitation-contraction coupling were observed in chemically skinned muscle bundles prepared from Wistar rat extensor digitorum longus muscle to clarify two questions: (1) whether triads localization and orientation are influenced by the sarcomere length and (2) whether triads localisation and orientation are influenced by the selective elimination of myosin filaments. The distance between triads and Z-lines depends on the sarcomere length: it increase with sarcomere length. There is a highly significant (p < 0.01) positive correlation between sarcomere length and the distance between triads and Z-line. The distance between Z-line and triads is dependent on sarcomere length, but the width of junctional gap remains constant when the sarcomere length was changed. Incubation in a concentration of KCI, which dissolves the myosin filaments. The localization and orientation of triads was not altered by the elimination of myosin filaments, however, the distance between the Z-line and triads becomes shorter when the myosin filaments was completely eliminated. There were significant differences (p < 0.01) between control and myosin filament eliminated fibres in the distances between Z-lines and triads (over 2 microns). These results indicate that the distance between triads and Z-lines depend on the sarcomere length and that there may be some connection(s) between triads and the myofibrils. There is that the elastic component responsible for tethering the triads in their normal position is interrupted either because it is normally attached to the myosin filaments, or because it is extracted by the conditions that dissociate myosin filaments.

Direct fermentative production of acyltylosins by genetically-engineered strains of Streptomyces fradiae

A tylosin-producer, Streptomyces fradiae, was transformed with plasmids carrying genes from Streptomyces thermotolerans that are involved in acyl modification of macrolide antibiotics. A transformant with pMAB3, in which macrolide 4"-O-acyltransferase gene (acyB1) and its regulatory gene (acyB2) are subcloned, produced several types of 4"-O-acyltylosins. A transformant with pAB11 delta EH containing macrolide 3-O-acyltransferase gene (acyA) in addition to the above two genes produced 3-O-acetyltylosin and 3-O-acetyl-4"-O-acyltylosins. Among the products of the latter transformant, 3-O-acetyl-4"-O-isovaleryltylosin (AIV) was detected as a minor component. When L-leucine, a precursor of isovaleryl-CoA, was added to the medium at the late stage of the fermentation, AIV content among the total macrolides increased ten-fold and AIV became a main product. This fact suggests that a high level of endogenous isovaleryl-CoA may be essential for the selective production of AIV by S. fradiae carrying pAB11 delta EH.

Color, orientation and cytochrome oxidase reactivity in areas V1, V2 and V4 of macaque monkey visual cortex

Color and orientation processing in the macaque monkey first segregates into cytochrome oxidase (CO)-rich blobs and -poor interblobs of area V1, from where the two streams flow through areas V2 and V4. This parallel representation is believed to enhance processing speed by compartmentalizing tasks of similar kinds, though our knowledge of the mechanisms is still elementary. We have examined the interaction and separation of color and orientation processing in neurons (n = 569) of the macaque visual cortex (V1, V2, V4) on the basis of microelectrode recordings. In all three areas, neurons selective for midspectral (MS) colors (e.g., yellow, green) were also found to be more orientation selective than those preferring endspectral (ES) colors (e.g., blue, red). The majority of achromatic (AC) cells responsive to bright stimuli were also orientation selective. When locations of cells and penetration columns were correlated with cytochrome oxidase (CO) landmarks in V1 and V2, V1 interblob and V2 interstripe cells were found to be predominantly midspectral and oriented, while V1 blob and V2 thin stripe cells were found to be predominantly endspectral and non-oriented. Cells preferring dark colors were found to cluster in thick stripes in V2, and in columns in V4. Separate clustering of midspectral (MS) and endspectral (ES) systems in V4 was also noted. With the results shown in a companion paper (Behav. Brain Res., 76 (1996) 51-70), the present data indicate that the visual system appears to optimize color and spatial acuity by separating chromatic information into non-oriented endspectral and oriented midspectral components.

Inhibition of neutrophil-superoxide generation by alpha-tocopherol and coenzyme Q

Effects of various derivatives of alpha-tocopherol (VE) and coenzyme Q (CoQ) on superoxide (O2.-) generation of neutrophils and protein kinase C (PKC) activity were examined. VE and CoQ8 inhibited O2.- generation of neutrophils stimulated by a protein kinase C mediated process monitored by cytochrome c reduction and spin trapping methods. The inhibitory action was observed not only with alpha-tocopherol, but also with beta-, gamma-, delta-tocopherols and with tocol which is a chemical similar to VE but lacking methyl groups on the chromanol ring structure and which is not a radical scavenger. By contrast, no inhibition was observed with 2-carboxy-2, 5, 7, 8-tetramethyl-6-chromanol (CTMC, trolox) or 2, 2, 5, 7, 8,-pentamethyl-6-chromanol (PMC) which are water soluble VE derivatives having radical scavenging activity. Compounds having a similar isoprenoid chain, such as CoQ, also have inhibitory activity on PKC-dependent O2.- generation of neutrophils. The inhibitory activity of CoQ derivatives is dependent on the length of the unsaturated isoprenoid chain. CoQ derivatives having 16, 24 and 32 carbon isoprenoid chains corresponding to CoQ4, 6, and 8 inhibited O2.- generation but 4 and 40 carbon isoprenoid chains corresponding to CoQ2 and 10 had no inhibitory activity on O2.- generation. Alpha-tocopherol and CoQ inhibited PKC activity but the ID50 for O2.- generation and PKC activity was different for each compound. However, no direct relationship between VE content and O2.- generation of neutrophils was observed. These results suggest that isoprenoids of VE and CoQ participate in the inhibition of the NADPH oxidase activation system through modulation of the neutrophil membrane probably by the inhibition of PKC.

Neuronal mechanisms of color categorization in areas V1, V2 and V4 of macaque monkey visual cortex

A landmark study conducted by Berlin and Kay (Basic Color Terms, University of California Press, Berkeley, 1969, pp. 1-12) demonstrates that well-developed languages contain exactly 11 basic color terms. The basic colors (8 chromatic and 3 achromatic) are situated in specific locations of color space, suggesting a fixed relationship between specific hue and luminance. To determine the physiologic origins of the basic colors, we have studied the responses of cells in visual cortical areas V1, V2 and V4 of the behaving macaque monkey, using chromatic and achromatic stimuli of varying luminance. A total of 569 cells (291 from V1, 205 from V2, 73 from V4) were obtained, and classified as 'B' (bright; 43-50% of the total cells in each area), 'D' (dark; 6-12% of the total), and 'B/D' (bright/dark; 27-28% of the total) color or non-color cells according to each cell's color/luminance preference in relation to the neutral gray background. About two thirds of 'B' cells in each area were color specific, whereas the proportion of color cells in 'B/D' and 'D' categories was lower. In all three areas (v1, V2, V4), color cells with preferences for midspectral colors (such as yellow, lime and green) also preferred high luminance levels, while color cells with preferences for endspectral colors (such as red and blue) responded preferentially to luminance levels closer to background. The date provide evidence for categorical color perception within the visual system, as well as providing a physiological basis for the increased saliency of endspectral contours observed at equiluminance in psychophysical studies.

Retina-derived POU-domain factor-1: a complex POU-domain gene implicated in the development of retinal ganglion and amacrine cells

A novel POU-domain protein, retina-derived POU-domain factor-1 (RPF-1), has been identified through the isolation of cDNA and genomic DNA clones. In the adult, RPF-1 is expressed only within the CNS, where its expression is restricted to the medical habenulla, to a dispersed population of neurons in the dorsal hypothalamus, and to subsets of ganglion and amacrine cells in the retina. The human RPF-1 gene spans > 125 kb and gives rise to multiple differentially spliced transcripts. In the human retina, the most abundant mRNA isoforms are derived from an alternate splicing event that inserts an evolutionarily conserved peptide of 36 amino acids into the DNA recognition helix of the POU-specific domain. In vitro, the RPF-1 POU domain lacking the insert binds to a consensus Oct-1 binding site, whereas the alternately spliced POU domain does not. RPF-1 protein first appears in the developing mouse retina at e11, where it localizes to neuroblasts that have recently migrated from the mitotic zone to the future ganglion cell layer. These data suggest that RPF-1 is likely to be involved in early steps in the differentiation of amacrine and ganglion cells.

Relation between patterns of intrinsic lateral connectivity, ocular dominance, and cytochrome oxidase-reactive regions in macaque monkey striate cortex

To help understand the role of long-range, clustered lateral connections in the superficial layers of macaque striate cortex (area V1), we have examined the relationship of the patterns of intrinsic connections to cytochrome oxidase (CO) blobs, interblobs, and ocular dominance (OD) bands, using biocytin based neuroanatomical tracing, CO histochemistry, and optical imaging. Microinjections of biocytin in layer 3 resulted in an asymmetric field (average anisotropy of 1.8; maximum spread--3.7 mm) of labeled axon terminal clusters in layers 1-3, with the longer axis of the label spread oriented orthogonal to the rows of blobs and imaged OD stripes, parallel to the V1/V2 border. These labeled terminal patches (n = 186) from either blob or interblob injections (n = 20) revealed a 71% (132 out of 186) commitment of patches to the same compartment as the injection site; 11% (20 out of 186) to the opposite compartment, and 18% (34 out of 186) to borders of blob-interblob compartments, indicating that the connectivity pattern is not strictly blob to blob, or interblob to interblob (p < 0.005; chi(2)). In injections placed within single OD domains (n = 11), 54% of the resulting labeled terminal patches (43 out of 79) fell into the same OD territories as the injection sites, 28% (22 out of 79) into the opposite OD regions, and 18% (14 out of 79) on borders, showing some connectional bias toward same-eye compartments (p < 0.02; ANOVA). Individual injection cases, however, varied in the degree (50-100% for CO patterns, 22-100% for OD patterns) to which they showed same-compartment connectivity. These results reveal that while connectivity between similar compartments predominates (e.g., blob to blob, right eye column to right eye column), interactions do occur between functionally different regions.