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Y Hokama

Publications and source records attributed to Y Hokama.

At least 19 recordsLinked to original sources
PubMed2006

Comparative analysis of purified Pacific and Caribbean ciguatoxin congeners and related marine toxins using a modified ELISA technique.

The monoclonal antibody to ciguatoxin (CTX) produced from a hybridoma cell line was assayed for the detection of four congeners of CTX: Pacific ciguatoxin-1 (P-CTX-1), Pacific ciguatoxin-2 (P-CTX-2), Pacific ciguatoxin-3 (P-CTX-3), and Caribbean ciguatoxin-1 (C-CTX-1) and related marine toxins, including domoic acid, palytoxin, and okadaic acid, using a modified enzyme-linked immunosorbent assay (ELISA). Lower detection limits were assessed and linearity was statistically established (P<0.05) for P-CTX-1, P-CTX-2, and P-CTX-3 and C-CTX-1 at concentrations ranging from 0 to 5.00 ng, while the other marine toxins showed statistically insignificant cross-reactivities at similar concentrations. Thus, the monoclonal antibody to CTX is able to specifically detect various CTX congeners at levels comparable to those naturally occurring in ciguatoxic fish.

Acrylamides↗
PubMed2006

Biological activity of the functional epitope of ciguatoxin fragment AB on the neuroblastoma sodium channel in tissue culture.

It is well established that the targeted receptor for ciguatoxin (CTX) in mammalian tissues is the sodium channel, affecting the influx of sodium into cells and altering the action potential and function of the cell. Since the syntheses of fragments of CTX has become available, our focus has been on the receptor functions of the west sphere AB and east sphere JKLM fragments using the neuroblastoma cell assay, guinea pig atrium assay, and the membrane immunobead assay (MIA). The data presented here suggest that the west sphere AB of the ciguatoxin molecule is the active portion and is responsible for the activation of the sodium channels.

Animals↗
PubMed2003

Chronic phase lipids in sera of chronic fatigue syndrome (CFS), chronic ciguatera fish poisoning (CCFP), hepatitis B, and cancer with antigenic epitope resembling ciguatoxin, as assessed with MAb-CTX.

Clinical reports and descriptions of chronic fatigue syndrome (CFS) and chronic ciguatera fish poisoning (CCFP) show great similarities in clinical symptomology. These similarities in the literature suggested the exploration of lipids in sera of CFS, CCFP, and other diseases with the membrane immunobead assay (MIA), which is typically used for screening ciguateric ocean fish. Sera from patients with other diseases, including hepatitis B, cancer, and diabetes, were included to assess the degree of specificity involved. Sera were treated with acetone in a ratio of 1 part serum to 4 parts acetone. The suspension was centrifuged, and the acetone layer was evaporated. The residue was weighed and redissolved in 1.0 mL methanol and tested by the MIA, undiluted and titered to 1:160. The undiluted acetone fraction of the 37 normal showed +/- activity to +activity with 16 no titer, 15 with 1:5 titer and two with 1:10 titer, and four with > or =1:40 titers. One hundred fifteen CFS sera showed 1 with 1+ and 114 with 2+ activity in the undiluted samples, 1 with 1:10 titer, 3 with 1:20 titer, 31 with 1:40 titer, 50 with 1:80 titer, and 30 with 160 titer. Thus 95.6% of the samples had > or =1:40 titer. Eight hepatitis B sera samples had > or =1:40 titers. Four CCFP samples had > or =1:40 titers. Three of 16 cancer samples had 1:40 titer. These data are summarized in Fig. 1. As shown in Table 1, a significant increase (P<0.001) in the chronic phase lipids (CPLs) was shown relative to the normal group. A preliminary chemical study in C18 octadecylsilyl columns showed all fractions (100% chloroform, 9:1 chloroform : methanol, 1:1 chloroform : methanol, and 100% methanol) to contain lipids reactive to MAb-CTX with different intensities. Prostaglandins were shown in 100% methanol fraction. Competitive MIA with crude fish ciguatoxin and CFS with synthetic JKLM ciguatoxin epitope suggested similarities in structure with ciguatoxin. This was compatible with the neuroblastoma assay demonstrated in the C(18) column fractions 9:1 and 1:1, chloroform : methanol solvents.

Acute Disease↗
PubMed2001

The biological assessment of flora and fauna as standards for changes in the near-shore ocean environment: a study of Barbers Point Harbor.

The biological assessments of the flora and fauna in the near-shore ocean environment, specifically Barbers Point Harbor (BPH), demonstrate the usefulness of these biological analyses for evaluation of the changes occurring following man-made excavation for expansion of the harbor. The study included identification and enumeration of macroalgae and dinoflagellates and analyses of herbivores and carnivores in four areas within the perimeter of the harbor and the north and south entrances into the harbor. Numbers of macroalgae varied between 1994 and 1999 surveys, with significant decrease in numbers in stations C, D and E. Stations A and B were similar between 1994 and 1999 with a slight increase in 1999. The significant differences were shown with the appearance of Gambierdiscus toxicus (G toxicus) in 1999 among the algae in stations A and B. Assessment of herbivores and carnivores with the immunological membrane immunobead assay using monoclonal antibody to ciguatoxin and related polyethers demonstrated an increase in fish toxicity among the herbivore from 1994-1999 (22% increase) with a decrease (22%) in non-toxic fish. This was also demonstrated in the carnivores, but to a lesser degree. It is suggested that the biological analyses of the flora and the fauna of the near-shore ocean environment are appropriate to assess the changes that occur from natural and man-made alterations.

Animals↗
PubMed2001

Diversity of marine biotoxins in the near-shore ocean area: presence of a palytoxin-like entity at Barber's Point Harbor, Oahu.

The presence of palytoxin or palytoxin-like compounds in fish extracts has been presented in this study. The hemolytic assay with sheep erythrocytes demonstrated the occurrence of hemolytic factors in fish extracts of Hawaiian reef fish from Barber's Point, Oahu. The rabbit anti-palytoxin inhibition assay with fish extracts and sheep erythrocytes demonstrated that palytoxin or its congener contributed to the lysis of sheep erythrocytes. From these results, it was concluded that sheep erythrocyte hemolysis was caused by palytoxin or palytoxin-like factors present in the fish extracts. Moderate correlation (R2) between mouse toxicity and sheep erythrocyte hemolysis was shown with 50 microg (R2 = 0.48) and 100 microg (R2 = 0.45) extracts. An inverse correlation of R2 = 0.64 was shown between hemolysis and MIA endpoint.

Acrylamides↗
PubMed2000

Evidence for palytoxin as one of the sheep erythrocyte lytic in lytic factors in crude extracts of ciguateric and non-ciguateric reef fish tissue.

The occurrence of palytoxin or its congener in fish extracts has been presented in this study. The presences of hemolytic factors in fish extracts of Hawaiian reef fish and their implication in ciguatera poisoning have been shown by the sheep erythrocyte assay. By use of the anti-palytoxin inhibition assay with fish extracts and sheep red blood cell (RBC), it was shown that palytoxin was one of the major factors in the lysis of sheep erythrocytes. Ouabain, an antagonist of palytoxin for the Na+/K+ ATPase receptor on RBC, also showed inhibition of sheep RBC lysis by fish extracts. From these results, it was concluded that, in part, palytoxin and other palytoxin-related, hemolysin-like factors in fish extracts were responsible for sheep cell hemolysis.

Acrylamides↗
PubMed1998

Malyngamides M and N from the Hawaiian Red Alga Gracilaria coronopifolia

Two new malyngamides, M and N (1, 2), were isolated along with malyngamide I acetate (3) from the Hawaiian red alga Gracilaria coronopifolia. Our results suggest that malyngamide N (2) is a revised structure of deacetoxystylocheilamide (5). The absolute configuration of malyngamide I acetate was deduced to be 3 using the reversed octant rule.

Journal Article↗
PubMed1998

Simplified solid-phase membrane immunobead assay (MIA) with monoclonal anti-ciguatoxin antibody (MAb-CTX) for detection of ciguatoxin and related polyether toxins.

The development of a simplified and modified procedure for the assessment of ciguatoxin (CTX) and related polyethers from ciguateric contaminated fish tissues is presented in this study. The previous method, stick-enzyme immunoassay (S-EIA) used an organic correction fluid-coated bamboo paddle stick for the solid phase; this new procedure, membrane immunobead assay (MIA), uses a plastic stick with a synthetic membrane laminated onto one end. The membrane is hydrophobic and serves as the solid-phase receptor for the binding of methanol-extracted CTX or its related polyether lipids from fish tissues. Detection of the bound polyether toxin(s) on the membrane is carried out with colored polystyrene beads coated with monoclonal antibody to CTX (MAb-CTX). Intensity of the color on the membrane is proportional to the amount of toxic polyethers on the membrane. The MIA is compared with previous procedures developed for CTX detection (S-EIA and solid-phase immunobead assay, SPIA) using State of Hawaii Department of Health (DOH) implicated ciguateric fishes, and reef fishes from Hawaii and Kwajalein. The data presented show good correlation between the three test systems, especially with ciguatera implicated fish and toxic, routinely assessed fishes in the mouse toxicity (MT) bioassay. Variations between MT results and those of the S-EIA, SPIA, and MIA of routine fishes are generally attributable to diverse toxins present in the fish species examined. The MIA is a simple, rapid, sensitive, and specific detection method for CTX and its related polyethers, with no reported false negative results. The test is useful for field and personal use and can be adapted to the laboratory for large-scale screening of potentially ciguateric fishes.

Animals↗
PubMed1996

Aplysiatoxin and debromoaplysiatoxin as the causative agents of a red alga Gracilaria coronopifolia poisoning in Hawaii.

The causative toxins of a red alga Gracilaria coronopifolia poisonings in Hawaii, which broke out in succession in September of 1994, were studied. Two major toxins were isolated from both extracts of the two original algal samples which caused separate poisonings. By spectroscopic method, these toxins were shown to be completely identical with aplysiatoxin and debromoaplysiatoxin which have previously been obtained from the sea hare and also from blue green algae. The human symptoms and the amount of these toxins in the original algal samples indicate that aplysiatoxin and debromoaplysiatoxin were the causative agents of the human poisoning incidents. This is the first reported case of the implication of aplysiatoxin and debromoaplysiatoxin in food poisoning. The existence of these toxins in the residue of algae washed in saline was confirmed by HPLC analysis. Furthermore, we observed blue-green algal parasitism on the surface of the toxic G. coronopifolia. Therefore, epiphytic organisms such as blue-green algae might be the true origin of the toxins in G. coronopifolia.

Carcinogens↗
PubMed1994

Evaluation of bioassay for toxicity of ciguateric fish and associated toxins.

Evaluation of the mouse toxicity assay symptom of hind leg paralysis (HLP) with mouse death by statistical analysis is presented in this study. The fishes assessed were herbivores including Ctenochaetus strigosus (kole), Ctenochaetus hawaiiensis, Acanthurus sandvicensis (manini), and Mugil cephalus (mullet); and the carnivores, Cephalopholis argus (roi) and Cheilinus rhodochrous (po'ou). The latter can also be considered an omnivore. The extracts of both herbivore and carnivore species appeared to be most toxic when HLP occurred in the mice. Ninety-three percent of the mice with HLP died, whereas when no HLP (NHLP) occurred, only 51% of the mice died. Carnivore flesh extracts (po'ou and roi) were least toxic with one death out of a total 22 mice. The unidentified toxin associated with HLP appears to differ in biological properties from that of ciguatoxin(s) in that it was not found in the flesh tissues of carnivores. Further chemical studies of this toxin(s) is being addressed presently.

Animals↗
PubMed1994

The first reported case of human ciguatera possibly due to a farm-cultured salmon.

This study is an individual case report of an imported cultured salmon which may have caused ciguatera. The individual's documented clinical symptoms, along with our immunological tests and bioassays (hemolytic, mouse toxicity and guinea-pig atrial assays) of the salmon extracts, strongly suggest that the salmon may have contained a ciguatoxin-like toxin (or toxins). The unique ability of the toxin(s) to block the sodium channel of the guinea-pig atrium, however, distinguishes it from ciguatoxin-1 isolated from moray eel liver.

Animals↗
PubMed1993

Evaluation of the Hawaiian reef fishes with the solid phase immunobead assay.

This study presents data on the evaluation of a laboratory ciguatera kit based on the solid phase immunobead assay (SPIA) for the detection of ciguatoxin in Hawaiian reef fish. The SPIA was performed on fish catches by volunteer fishermen throughout the State of Hawaii. A total of 1,067 fish of various species were tested for ciguatoxin (CTX) using the SPIA kit. Of the total 1,067 fish tested, 510 were from Oahu, 402 from Hawaii, and 75 from Maui. The number of fish from Molokai, Kauai, and Lanai were 23, 20, and 7 respectively. Twenty percent of the total fish tested were positive, 41% borderline, and 39% negative for ciguatoxin. The highest percentage of SPIA- positive fish were from Hawaii (27%) followed by Oahu (19%) and Kauai (15%). These results correlate with the reported incidents from the Department of Health (DOH) of actual ciguatera poisoning in the State of Hawaii. Fish in all three categories of the SPIA test values were eaten. No false negatives were noted with individuals eating SPIA negative fish. Of the 232 SPIA borderline values eaten, 3 species of fish caused ciguatera poisoning. These fish included 2 papio, 1 mullet, and 1 po'ou. Of the 17 SPIA positive fish eaten, 5 caused ciguatera poisoning: 2 papio, a kole, an uhu, and a weke. The SPIA ciguatera test did protect the public when only SPIA-negative fish were eaten. The borderline and positive SPIA fish were generally unsafe, especially the positive fish. The data indicated that the probability of getting ciguatera with a SPIA positive fish was 1 out of 3.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗