A double-functionalized cyclen with carbamoyl and dansyl groups (cyclen = 1,4,7,10-tetraazacyclododecane): a selective fluorescent probe for Y(3+) and La(3+)

A cyclen (=1,4,7,10-tetraazacyclododecane) doubly functionalized with three carbamoylmethyl groups and one dansylaminoethyl (dansyl = 2-(5-(dimethylamino)-1-naphthalenesulfonyl) group (L(2) = 1-(2-(5-(dimethylamino)-1-naphthalenesulfonylamido)ethyl)-4,7,10-tris(carbamoylmethyl)-cyclen) was synthesized and characterized. Potentiometrtic pH titration and UV spectrophotometric titration of L(2) served to determine deprotonation of the pendant dansylamide (L(2) --> H(-1)L(2)) with a pK(a) value of 10.6, while the fluorometric titration disclosed a pK(a) value of 8.8 +/- 0.2, which was assigned to the dansyl deprotonation in the excited state. The 1:1 M(3+)-H(-1)L(2) complexation constants (log K(app) = 6.0 for Y(3+) and 5.2 for La(3+), where K(app)(M-H(-1)L(2)) = [M(3+)-H(-1)L(2)]/[M(3+)](free)[L(2)](free) (M(-1)) at pH 7.4) were determined by potentiometric pH titration and UV and fluorescence spectrophotometric titrations (excitation at 335 nm and emission at 520 nm) in aqueous solution (with I = 0.1 (NaNO(3))) and 25 degrees C. The X-ray structure analysis of the Y(3+)-H(-1)L complex showed nine-coordinated Y(3+) with four nitrogens of cyclen, three carbamoyl oxygens, and the deprotonated nitrogen and a sulfonyl oxygen of the dansylamide. The crystal data are as follow: formula C(28)H(49)N(11)O(13.5)SY (Y(3+)-H(-1)L(2) x 2(NO(3)(-)) x 2.5H(2)O), M(r) = 876.73, monoclinic, space group P2(1)/n (No. 14), a = 18.912(3) A, b = 17.042(3) A, c = 24.318(4) A, beta = 95.99(1) degrees, V = 7794(2) A(3), Z = 8, R1 = 0.099. Upon M(3+)-H(-1)L(2) complexation, the dansyl fluorescence greatly increased (8.6 and 3.8 times for Y(3+) and La(3+), respectively) in aqueous solution at pH 7.4. Other lanthanide ions also yielded Ln(3+)-H(-1)L(2) complexes with similar K(app) values, although all the dansyl fluorescences were weakly quenched. On the other hand, zinc(II) formed only a 1:1 Zn(2+)-L(2) complex at neutral pH with negligible fluorescence change. The X-ray crystal structure of the Zn(2+)-L(2) complex confirmed the pendant dansylamide being noncoordinating. The crystal data are as follow: formula C(28)H(51)N(11)O(14)SZn (Zn(2+)-L(2) x 2(NO(3)(-)) x 3H(2)O), M(r) = 863.22, monoclinic, space group C2/n (No. 15), a = 35.361(1) A, b = 13.7298(5) A, c = 18.5998(6) A, beta = 119.073(2) degrees, V = 7892.3(5) A(3), Z = 8, R1 = 0.084. Other divalent metal ions did not interact with L(2) at all (e.g., Mg(2+) and Ca(2+)) or interacted with L(2) with the dansyl fluorescence quenched (e.g., Cu(2+)).

Model studies for molecular recognition of carbonic anhydrase and carboxypeptidase

Model studies using Zn(2+) complexes of various derivatives of macrocyclic triamines ([12]aneN(3)) and tetraamines (cyclen) have been found to be useful in elucidating and understanding the intrinsic properties of substrate or inhibitor recognition by zinc ions at the active centers of carbonic anhydrase and carboxypeptidase.

Efficient repetitive gene delivery to skeletal muscle using recombinant adenovirus vector containing the Coxsackievirus and adenovirus receptor cDNA

To improve adenovirus-mediated gene delivery to skeletal muscle, we have used a recombinant adenovirus vector encoding the human Coxsackievirus and adenovirus receptor (hCAR). Because CAR is expressed at a lower level in rodent myoblasts and muscle fibers than in other tissues, we expected that elevated expression of CAR in skeletal muscle would improve the efficacy of adenovirus-mediated gene transfer. Since the mouse myoblasts, C2C12 cells, showed low sensitivity to infection by recombinant adenovirus 5, we initially infected these cells at a high multiplicity of infection (MOI) of 250 with the recombinant adenovirus containing hCAR cDNA and LacZ gene. Subsequent infection by recombinant adenovirus containing the marker gene, green fluorescence protein, became efficient even at a low MOI of 25. Thus, elevated hCAR expression in mouse muscle fibers made a second virus inoculation at low doses possible. We also demonstrated that the elevated hCAR expression did not influence muscle membrane integrity. Our results suggest that co-expression of CAR and a therapeutic gene by adenovirus vector constitutes a novel strategy to advance gene therapy for hereditary muscle diseases.

Novel mechanism of blocking axonal Na(+) channels by three macrocyclic polyamine analogues and two spider toxins

1. The mechanism of Na(+) channel block by three macrocyclic polyamine derivatives and two spider toxins was studied with voltage clamp and internal perfusion method in squid axons. 2. All these chemicals specifically block Na(+) channels in the open state only from the internal surface, and do not affect K(+) channels. 3. The blocking effect is enhanced as the depolarizing pulse becomes larger. Blocked channels are unable to shift to the inactivated state. 4. In the case of cyclam and guanidyl-side armed cyclam (G-cyclam), quick release of these chemicals from the binding sites is proven by the increase in the tail current and prolongation of the time course of the off gating current. On the other hand, in the presence of N-4 and the spider toxins, their detachment was delayed significantly. 5. Molecular requirements for the block of Na(+) channels by these molecules are the presence of positive charge and hydrophobicity.

In-vivo sensitivity of Plasmodium vivax isolates from Rond nia (western Amazon region, Brazil) to regimens including chloroquine and primaquine

Seventy-nine adults with Plasmodium vivax malaria, from the Porto Velho area of Rond nia (western Amazon region, Brazil), gave informed consent to participate in a blind, clinical study of two regimens of treatment with chloroquine (CQ) and primaquine. The effectiveness of the 'classical' regimen (CQ for 3 days, followed by primaquine for 14 days) was compared with that of a 'short' regimen in which the two drugs were given simultaneously for 5 days. There were no cases of recrudescence indicative of CQ resistance (i.e. within 30 days of the first treatment dose) among the 73 patients who each completed a full, supervised course of treatment. However, 10 cases of apparent relapse were observed (all > 60 days after first treatment dose), representing 6.5% (2/31) of the patients who completed 60 days of follow-up after the classical treatment and 26.7% (8/30) of the short-regimen patients who completed the same period of follow-up. PCR-based comparison of parasitic DNA collected pre- and post-treatment was successful for eight of the 10 cases of apparent relapse and indicated that two such cases, both given the short regimen of treatment, were, in fact, probable cases of re-infection rather than of relapse. The results indicate that the classical schedule of treatment with chloroquine and primaquine was more effective at preventing relapses than the short regimen. However, since prolonged treatment with primaquine often produces side-effects that are severe enough to reduce compliance, the short schedule could be a useful alternative for malaria control in endemic areas of the Amazon region.

Identification of human chromosome 22 transcribed sequences with ORF expressed sequence tags

Transcribed sequences in the human genome can be identified with confidence only by alignment with sequences derived from cDNAs synthesized from naturally occurring mRNAs. We constructed a set of 250,000 cDNAs that represent partial expressed gene sequences and that are biased toward the central coding regions of the resulting transcripts. They are termed ORF expressed sequence tags (ORESTES). The 250,000 ORESTES were assembled into 81,429 contigs. Of these, 1, 181 (1.45%) were found to match sequences in chromosome 22 with at least one ORESTES contig for 162 (65.6%) of the 247 known genes, for 67 (44.6%) of the 150 related genes, and for 45 of the 148 (30.4%) EST-predicted genes on this chromosome. Using a set of stringent criteria to validate our sequences, we identified a further 219 previously unannotated transcribed sequences on chromosome 22. Of these, 171 were in fact also defined by EST or full length cDNA sequences available in GenBank but not utilized in the initial annotation of the first human chromosome sequence. Thus despite representing less than 15% of all expressed human sequences in the public databases at the time of the present analysis, ORESTES sequences defined 48 transcribed sequences on chromosome 22 not defined by other sequences. All of the transcribed sequences defined by ORESTES coincided with DNA regions predicted as encoding exons by genscan. (http://genes.mit.edu/GENSCAN.html).

Selective recognition of consecutive G sequence in double-stranded DNA by a zinc(II)-macrocyclic tetraamine complex appended with an anthraquinone

A zinc (II) complex with a macrocyclic tetraamine appended with an anthraquinone ((9,10-anthraquinon-2-yl)methyl-1,4,7,10-tetraazacyclododecane, ZnL, anthraquinonyl-cyclen) selectively recognizes consecutive G sequence in double-stranded DNA. The affinity of the Zn2+-anthraquinonyl-cyclen to consecutive dG groups in DNA was disclosed by comparison of K(app) values (=[DNA-bound ZnL]/[uncomplexed ZnL][uncomplexed nucleobase in DNA]) determined by the UV spectrophotometric titrations at pH 8, I=0.1 (NaNO3), and 25 degrees C for poly(dG) x poly(dC) (K(app) = 1.5 x 10(5) M(-1)), poly(dG-dC)2 (2.8 x 10(4) M(-1)), poly(dA-dT)2 (4.3 x 10(4) M(-1)), and calf thymus DNA (2.8 x 10(4) M(-1)). The corresponding K(app) values with the Zn2+-free ligand were 5.3 x 10(3) M(-1), 7.4 x 10(3) M(-1), 7.4 x 10(3) M(-1), and 5.9 x 10(3) M(-1), respectively. The selective recognition of consecutive G sequence was concluded from the DNase I footprinting of SV40 early promotor DNA fraction (197 bp) containing a TATA box and six GC boxes. The present finding is in remarkable contrast to the previous selective T-recognition by Zn2+-cyclen complexes appended with acridine, quinoline(s), and naphthalene(s) [J. Am. Chem. Soc. 121 (1999) 5426]. While the Zn2+-acridinyl-cyclen inhibited TATA binding protein from interacting with a TATA box consensus DNA [J. Inorg. Biochem. 79 (2000) 253], the present Zn2+-anthraquinonyl-cyclen inhibited the Sp1 transcriptional factor protein from interacting with a GC box-consensus DNA.

Antiulcer effectiveness of Maytenus aquifolium spray dried extract

The antiulcer activity of Maytenus aquifolium spray dried extract was studied in rats. Ulcers were induced by means of three experimental models: acidified-ethanol, indomethacin and acute stress. The extract was found to have significant antiulcer activity against all the models studied. These results show that preparation of the extract by means of the spray dried technique does not alter the biological activity of Maytenus aquifolium.

Differential expression of mouse alpha5(IV) and alpha6(IV) collagen genes in epithelial basement membranes

We first completed the primary structure of the mouse alpha5(IV) and alpha6(IV) chains, from which synthetic peptides were produced and a chain-specific monoclonal antibodies were raised. Expression of collagen IV genes in various basement membranes underlying specific organ epithelia was analyzed by immunohistochemical staining using these monoclonal antibodies and other antibodies from human and bovine sequences. It was possible to predict the presence of the three collagen IV molecules: [alpha1(IV)](2) alpha2(IV), alpha3(IV)alpha4(IV)alpha5(IV), and [alpha5(IV)](2)alpha6(IV). In skin basement membrane two of the three forms, [alpha1(IV)](2)alpha2(IV) and [alpha5(IV)](2)alpha6(IV), were detected. The alpha3(IV)alpha4(IV)alpha5(IV) molecule was observed as the major form in glomerulus, alveolus, and choroid plexus, where basement membranes function as filtering units. The molecular form [alpha5(IV)](2)alpha6(IV) was present in basement membranes in tubular organs such as the epididymis, where the tubes need to expand in diameter. Thus, the distribution of the basement membranes with different molecular composition is consistent with tissue-specific function.

One-step enzyme-linked immunosorbent assay (ELISA) for measurement of serum free leptin

In man, circulating leptin levels are increased with obesity and are regulated by a complex of hormonal, feeding and body-weight changes. Accurate and precise methods to quantitate circulating serum free leptin (f-leptin) concentrations are needed for physiological and clinical studies. We developed a one-step enzyme immunoassay to measure human f-leptin in serum. The detection limit was 0.40 ng/ml. The recovery of leptin added to serum was 90.8-102.8%. The within-run and between-day coefficients of variation (C.V.) ranged from 2.8 to 7.7 and 5.7 to 9.7%, respectively, and the immunoassay had an overall recovery rate for serial dilution in the range of 94. 0-109.9%. Measured serum f-leptin concentrations in 201 adults correlated (r=0.449, P<0.001) directly with body mass index (BMI kg/m(2)), particularly when results were separated by gender (r=0. 709 for male, P<0.001; r=0.643 for female, P<0.001). We conclude that this one-step enzyme immunoassay is accurate for measuring f-leptin in human serum.

Dimetallic hydrolases and their models

Recent mechanistic studies of Fe3+/M2+ purple acid phosphatase present conflicting pictures about the roles of the metals. Recent model studies with Co3+/Co3+ and Fe3+/Fe3+ complexes have supported each conflicting mechanism for phosphate hydrolysis. With dizinc and trizinc complexes, the competitive binding of hydroxyl and phosphate substrates has been demonstrated.

Controlling gene expression by zinc(II)-macrocyclic tetraamine complexes

The zinc(II) complexes of 12-membered macrocyclic tetraamines (1,4,7,10-tetraazacyclododecane, cyclen) appended with one or two aryl-methyl group(s) (quinolyl-methyl, naphthyl-methyl, and acridinyl-methyl) selectively bind to thymines in a TATA box of the SV40 early promoter region and thus inhibit the binding of a transcriptional factor, TATA binding protein. These Zn2+-cyclen derivatives also act as inhibitors of DNA-targeted enzymes, type I and type II topoisomerases. They also exhibited strong antimicrobial activities for the gram-positive bacterial strain. These biochemical and biological properties were compared with those of conventionally established AT-recognizing drugs, distamycin A and DAPI. The Zn2+-cyclen complexes are a new type of small molecular, genetic transcriptional regulation factor.

Why zinc in zinc enzymes? From biological roles to DNA base-selective recognition

Intrinsic chemical properties of the zinc(II) ion in zinc enzymes have been investigated by the model of 1:1 Zn2+-macrocyclic polyamine complexes, including Zn2+-1,5,9-triazacyclododecane ([12]aneN3) and 1,4,7,10-tetraazacyclododecane (cyclen). The physiologically most suitable pKa values for the Zn2+-bound H2O in enzymes were illustrated by the first model Zn2+-[12]aneN3 complex, which mimics the essential kinetic and thermodynamic roles of Zn2+ in carbonic anhydrase. The activation of proximate serine residues (in alkaline phosphatase) and activation of alcohols for hydride transfer to NAD+ (in alcohol dehydrogenase) were also mimicked by Zn2+ -[12]aneN3 complexes. The functions of two zincs in dinuclear metallophosphatases were explained by a new dinuclear Zn2+-cryptate. For an aldolase type II model, a Zn2+-cyclen derivative showed facile enolate formation from a proximate carbonyl pendant under physiological conditions. The strong anion affinities, which Zn2+ intrinsically possesses, were exploited into novel selective nucleobase thymine (or uracil) recognition of Zn2+-cyclen complexes by the strong Zn2+ -imido anion bond formation. The Zn2+-aromatic-pendant cyclen complexes selectively bind to T (or U) in single- and double-stranded DNA (or RNA). Thus, Zn2+ complexes act like molecular zippers to break A-T pairs in DNA, which was proven by various physicochemical measurements and DNA footprinting assays. These Zn2+ complexes showed some relevant biochemical and biological properties such as inhibition of transcriptional factor, TATA binding protein, or strong antimicrobial activities to gram-positive bacterial strains.

Effect of Maytenus aquifolium extract on the pharmacokinetic and antiinflammatory effectiveness of piroxicam in rats

This study explored the interference by Maytenus aquifolium leaves hydroalcoholic (MALHE) extract, administered orally, on the pharmacokinetic and antiinflammatory activity of piroxicam in rats. The results showed no significant difference in piroxicam bioavailability with simultaneous application of MALHE. MALHE also had no effect on the inhibitory effect of piroxicam on inflammatory processes induced by carrageenan and complete Freund adjuvant.

ELISA for a complexed antigen with a monoclonal antibody blocking reaction with the free antigen-assay-specific for complexed prostate-specific antigen

We have developed an enzyme-linked immunoassay (ELISA) for serum complexed-antigen (prostate-specific antigen; PSA)(c-PSA) with simultaneous blocking of free-antigen (PSA)(f-PSA). The assay utilizes three different monoclonal antibodies (MAbs) recognising three distinct PSA epitopes. The detection limit was established as 0.19 microg/l (n=20, mean of zero standard+2S.D.) and the average recovery of f-PSA was 98-100%. The within-run and between-day coefficients of variation (CV) ranged from 2.1% to 3.2% and 2.8% to 6.3%, respectively. There was a good correlation between serum c-PSA measured by the present ELISA and PSA-alpha(1)-antichymotrypsin complex (PSA-ACT) concentrations (r=0.991). This method should provide a better tool for discriminating between benign and malignant prostatic disease.

Establishment and characterization of cell lines derived from serous adenocarcinoma (JHOS-2) and clear cell adenocarcinoma (JHOC-5, JHOC-6) of human ovary

The cell lines designated JHOS-2, JHOC-5 and JHOC-6 were established from epithelial ovarian carcinomas. JHOS-2 was established from a serous adenocarcinoma of a 45-year-old Japanese woman, JHOC-5 from a recurrent tumor of a clear cell adenocarcinoma of a 47-year-old Japanese woman and JHOC-6 from a tumor of a clear cell adenocarcinoma of a 43-year-old Japanese woman. These cell lines have grown well and serial passages were successively carried out more than 20 times. The monolayer cultured cells revealed neoplastic and pleomorphic features, and grew in multilayers. Electron micrographs revealed epithelial origins that had desmosomes and tonofilaments.

Natural and synthetic double-stranded DNA binding studies of macrocyclic tetraamine zinc(II) complexes appended with polyaromatic groups

The characteristic binding mode of zinc(II) complexes of macrocyclic tetraamines (1,4,7,10-tetraazacyclododecane, cyclen) appended with one or two arylmethyl group(s) [(4-quinolyl)methyl-, 1,7-bis(4-quinolyl)methyl-, (1-naphthyl)methyl-, 1,7-bis(1-naphthyl)methyl-, and (9-acridinyl)methyl-cyclen] to double-stranded calf thymus DNA and synthetic DNAs [poly(dA)-poly(dT), poly(dA-dT)2, poly(dI).poly(dC), poly(dI-dC)2, poly(dG) poly(dC), and poly(dG-dC)2] has been examined by spectrophotometric methods, Tm measurement, and inhibition of these DNA-directed transcriptions in vitro. Various hypochromic and bathochromic effects on the pendant aromatic absorption spectra of the complexes were observed in titration with the native and synthetic DNA. The binding constants Kapp (=[bound cyclen derivatives]/[unbound cyclen derivatives][DNA phosphates] M(-1)), at 25 degrees C in 10 mM EPPS (pH 8.0) containing 0.1 M Na+, were determined and compared with those of the corresponding Zn2+ -free ligands. The results showed that the Zn2+ -cyclen complexes interact with the DNA more strongly than the corresponding diprotonated ligands, leading to a stronger stacking of the pendant aromatic rings. The binding of Zn2+ -(9-acridinyl)methyl-cyclen to calf thymus DNA was competed by an AT-selective, minor groove binder, distamycin, but not by a major groove binder, methyl green. In an unusual interaction of excess Zn2+ -(9-acridinyl)methyl-cyclen with poly(dA).poly(dT), the Zn2+ -cyclen moiety went into the minor groove to make coordination bonds with the deprotonated imides of the thymines, resulting in disruption of the poly(dA).poly(dT) duplex. Thymine-containing DNA-directed transcription with Escherichia coli RNA polymerase in vitro was inhibited by the Zn2+ -(9-acridinyl)methyl-cyclen. The 50% inhibition concentrations of the transcription (IC50) were 22-45 microM with poly(dA).poly(dT) or poly(dA-dT)2 as templates, while with poly(dG-dC)2 as a template the IC50 value was 110 microM.

A second peak of egg excretion in Strongyloides ratti-infected rats: its origin and biological meaning

In Strongyloides ratti-infected rats, 2 peaks of egg excretion were observed; a large one with maximum egg production on days 7-8 of infection and a small more inconspicuous one around day 25. The second peak, which had been ignored in most studies, was produced by adults in the caecum and the colon. The adults were larger in length and had more embryonated eggs in the uterus compared with adults in the small intestine at day 25 post-infection. It is suggested that parasitic adults once expelled from the small intestine resettle and recover in the large intestine. Filter paper faecal culture carried out for 9 days at different days post-infection revealed that the total number of infective larvae that developed during the second peak was twice the number that developed during the first peak, despite the fact that total egg output during the second peak was less than one twentieth of the first peak. The results suggest that the small second peak was as important as the first one in the transmission of S. ratti.

Pharmacokinetic profile and adverse gastric effect of zinc-piroxicam in rats

Complexation of piroxicam with zinc extends its absorption time in rats. The time of peak concentration value for complexed piroxicam was 5.27 hr compared to only 2.56 hr for the uncomplexed agent. Piroxicam and zinc-piroxicam show similar inhibitory effects on carrageenin-induced paw edema. Zinc-piroxicam is less irritating than piroxicam on the gastric mucosa.

Expression and functional characteristics of calpain 3 isoforms generated through tissue-specific transcriptional and posttranscriptional events

Calpain 3 is a nonlysosomal cysteine protease whose biological functions remain unknown. We previously demonstrated that this protease is altered in limb girdle muscular dystrophy type 2A patients. Preliminary observations suggested that its gene is subjected to alternative splicing. In this paper, we characterize transcriptional and posttranscriptional events leading to alterations involving the NS, IS1, and IS2 regions and/or the calcium binding domains of the mouse calpain 3 gene (capn3). These events can be divided into three groups: (i) splicing of exons that preserve the translation frame, (ii) inclusion of two distinct intronic sequences between exons 16 and 17 that disrupt the frame and would lead, if translated, to a truncated protein lacking domain IV, and (iii) use of an alternative first exon specific to lens tissue. In addition, expression of these isoforms seems to be regulated. Investigation of the proteolytic activities and titin binding abilities of the translation products of some of these isoforms clearly indicated that removal of these different protein segments affects differentially the biochemical properties examined. In particular, removal of exon 6 impaired the autolytic but not fodrinolytic activity and loss of exon 16 led to an increased titin binding and a loss of fodrinolytic activity. These results are likely to impact our understanding of the pathophysiology of calpainopathies and the development of therapeutic strategies.

Gastric antiulcerogenic effects of Stryphnodendron adstringens in rats

The antiulcer activity of the total extract and the fractions of Stryphnodendron adstringens was studied in rats and compared with that of cimetidine. Ulcers were induced in rats by means of three experimental models: acute stress, acidified-ethanol and indomethacin. The total extract and the fractions were found to have significant antiulcer activity in the case of the acute stress and acidified-ethanol models. These findings support the use of S. adstringens extracts in the treatment of gastric lesions.

A highly sensitive enzyme-linked immunoassay for serum free prostate specific antigen (f-PSA)

Monoclonal antibodies (MAbs) were generated against human prostate specific antigen (PSA) to allow development of a sensitive free-PSA (f-PSA) assay. Of a total of 211, 12 could detect only f-PSA, the other 199 MAbs binding to both f-PSA and complex-PSA. In the present study, one MAb (no. 5C6) specific for f-PSA and another (no. 79) reacting with both forms were used to develop an enzyme-linked immunoassay (ELISA) for serum f-PSA. The detection limit was established as 0.008 microg/l (n = 20, mean of zero standard + 3 S.D.) and the average recovery of f-PSA was 93-102%. The within-run and between-day coefficient of variation (CV) varied from 5.4-7.4% and 4.8-6.5%, respectively. The cross-reactivity of the assay to PSA-alpha1-antichymotrypsin complex was determined to be < 0.4%.

Wuchereria bancrofti antigenaemia in Sri Lanka

The prevalence of Wuchereria bancrofti antigenaemia determined in 353 subjects in Matara, Sri Lanka by Og4C3 ELISA was 20.7%. Positive rates obtained with the same subjects by 1 ml Nuclepore filtration and 60 microl thick blood smear were 11.3% and 7.9%, respectively. Antigen levels were positively associated with microfilaria counts. Two-thirds of antigen-positive and microfilaria-negative (Ag+/Mf-) individuals were > 25-year-old, but younger age groups (< or = 25-year-old) tended to have proportionally more Ag+/Mf- cases. Possible origins of the Ag+/Mf- status are discussed.

S-cone contribution to pupillary responses evoked by chromatic flash offset

On a green or red background, the action spectrum of the pupillary responses evoked following the offset of chromatic test flashes shows a prominent short-wavelength lobe and suggests the contribution from photoreceptors other than the previously inferred M- and L-cones (Kimura & Young, Vision Research (1996). 36, 1543-1550), most likely from S-cones. Systematic changes in the shape of the intensity versus amplitude functions with test wavelengths and in the shape of the short-wavelength lobe with response amplitude criteria suggest an antagonistic interaction involving the short- and longer-wavelength photoreceptors.