Hemodynamics of ophthalmic artery and central retinal artery and correlation with other factors in patients with primary open angle glaucoma

OBJECTIVE

To investigate the hemodynamics of ophthalmic artery (OA) and central retinal artery (CRA) in patients with primary open angle glaucoma(POAG) and analyse the correlation between hemodynamics of OA and CRA and other factors.

METHODS

The hemodynamics of OA and CRA in normal persons (102 eyes) and glaucomatous patients (102 eyes) were measured by Colour Doppler Image (CDI). The linear correlation analysis was made between OA and CRA about each of the following parameters: the peak systolic flow velocity (Vmax), the end diastolic velocity (Vmin). The multiple stepwise regression analysis was taken to investigate the correlation between each of the following hemodynamics of OA and CRA: Vmax and Vmin in 74 eyes with POAG and each of the following related factors in hemorrheology: whole blood apparent viscosity at low, medium and high shear rate, plasma viscosity and hematocrit. The multiple linear regression was applied to investigate the correlation between each of the following hemodynamics of OA and CRA: Vmax and Vmin in 69 eyes with POAG and each of the following blood vessel filling time: the arm-retinal artery (A-AT) and retinal artery-venous (A-VT) of the fundus fluorescein angiography(FFA).

RESULTS

The Vmax, Vmin and time-averaged maximum velocity (Vmean) of OA and CRA in patients with POAG were lower than those in normal persons, but the resistance index (RI) of OA and CRA was higher than those in normal. There was a positive correlation between OA and CRA in Vmin, but a negative correlation between Vmin of OA and plasma viscosity. The whole blood apparent viscosity at low shear rate was clodely related to Vmax and Vmin of CRA. Also there was a negative correlation between Vmax of CRA and A-AT of the FFA.

CONCLUSION

There was abnormal hemodynamics, which is influenced by blood viscosity, of OA and CRA in patients with POAG. Abnormal hemodynamics can affect the blood supply to optic disc and retina in POAG.

A domain flip as a result of a single amino-acid substitution

BACKGROUND

The self-assembly properties of beta domains are important features of diverse classes of proteins that include cell-adhesion molecules, surface receptors and the immunoglobulin superfamily. Immunoglobulin light-chain variable domains are well suited to the study of structural factors that determine dimerization, including how residues at the interface influence the preferred dimer arrangement.

RESULTS

Single-site mutants of light-chain variable domain Len, designated LenQ38E and LenK30T, formed 'flipped' dimers in which one domain was rotated by about 180 degrees compared with the native protein. The dimer in the native protein is similar to that found between variable domains in Fab immunoglobulin fragments. When compared to the native dimer, more surface area is buried, and more hydrogen bonds and salt bridges are formed between the monomers in the flipped conformation.

CONCLUSIONS

Immunoglobulin light-chain variable domains can form a minimum of two distinct quaternary structures. Single-site mutations resulting from changes of one base, such as the exchange of Gln38 to Glu or Lys30 to Thr, change the 'conventional' dimer of protein Len to a flipped arrangement. Native Len is not found in the flipped-domain dimer conformation because it would have excess positive electrostatic potential at the dimer interface that is not compensated by other forces. Excess negative or positive electrostatic potential at the dimer interface can have a determining effect on the mode of dimerization.

[Parapharyngeal space neoplasms and surgical treatment]

This paper reports surgical treated 66 cases of parapharyngeal space neoplasms. They consist of primary 52 and secondary 14 cases, which were 59 benign and 7 malignant tumors. The surgical procedures which have been used are oral approach in 5 cases, the parotid approach in 5 cases, the cervical approach in 47 cases, the cervical approach with mandibular swing in 7 cases and the postaurical C incision approach in 2 cases. The procedures and indications of the cervical approach or (and) its combination with mandibular swing are outlined. It is considered that these two surgical procedures can provide very safe and efficacious approaches to the removal of the primary parapharyngeal space neoplasms encountered.

Leptin, the hypothalamus and the regulation of adiposity

The hypothalamus contains a wealth of peptide and non-peptide neurotransmitters, many of which have been shown experimentally to influence feeding behaviour and energy metabolism. Regulatory activities as complex as these are likely to be controlled by numerous neurotransmitters interacting at a variety of levels. The hierarchy of command of these neuronal circuits is not known, but it is possible that some converge on to a final common pathway, governed by the actions of a single neurotransmitter, through which all other influences ultimately operate. This review will discuss several of the more recently identified neurotransmitters and consider their validity as candidates in the regulation of energy homeostasis.

Mirror writing in the elderly

OBJECTIVE

To determine if examination of mirror writing in the elderly could be used to assess the degradation of the brain function.

METHODS

The occurrence of mirror writing in 146 subjects was examined. Among them, 104 were males and 42 females. All subjects were university graduates. Age ranged from 40 to 85 years with an average of 62.7 +/- 13.4. These subjects were divided into two groups, a non-elderly group consisting of 60 subjects (41.1%) and an elderly group 86 subjects (58.9%). All 146 subjects were examined with 10 items for determination of handedness, mini-mental state examination and the written language of Chinese Aphasia Examination Scale (Draft) including spontaneous writing, writing from dictation and copying. The above mentioned performances of written language were done by left and right hand.

RESULTS

The results of examination revealed that in 146 subjects there were 7 subjects with mirror writing, which occurred only in the elderly group, accounting for 8.1%. In the elderly group, mirror writing was found in one subject of 70-79 years group and 6 subjects of age over 80 years. Mirror writing appeared in the elderly was of mild degree with an average percentage of 1.9 +/- 0.4.

CONCLUSION

It is suggested that examination of mirror writing in the elderly may be used to assess the degradation of the brain function in senile subjects.

[In vitro study on arsenic trioxide-induced apoptosis of retinoic acid resistant acute promyelocytic leukemia cell line(MR-2)]

OBJECTIVE

To study the possible mechanisms of arsenic trioxide (As2O3) in the treatment of acute promyelocytic leukemia (APL).

METHODS

Retinoic acid resistant APL cell line MR-2 was used as in vitro model. The effect of As2O3 on MR-2 cell line was observed by cell viability, cell growth, cell morphology, flow cytometry assay, NBT reduction test and immunofluorescence analysis.

RESULTS

1.0 mumol/L of As2O3 could induce apoptosis of MR-2 cells and it correlated with the degradation of PML-RAR alpha fusion protein.

CONCLUSIONS

The therapeutic effect of As2O3 for APL possibly differs from that of ATRA, however, PML-RAR alpha fusion protein may be the target of both the therapy.

[Parapharyngeal space neoplasms]

OBJECTIVE

To study parapharyngeal space (PPS) neoplasms which are rarely seen clinically.

METHODS

A retrospective review was made of 59 patients with PPS neoplasm operated on from 1986 to July, 1997 in our institution.

RESULTS

Neurogenic tumors were the most common neoplasms, which constituted about 60 percent in the primary parapharyngeal space neoplasms. High-resolution computed tomography or magnetic resonance imaging was essential for diagnosis and presurgical planning. The transcervical approach was the preferred procedure for 75% benign parapharyngeal tumors. Middle mandibulotomy was used in 3 cases, including 2 small tumors confined to the superior aspect of the PPS and 1 carotid body tumor which extended to the skull base. Lateral skull base approach was utilized for 1 schwannoma originating in the jugular foramen with extension into the PPS.

CONCLUSIONS

We believe that transoral approach can be used for small tumors and transparotid approach may be especially indicated for removal of deep lobe parotid tumors with extension to the PPS. Middle mandibulotomy is a safe and efficacious approach for the removal of special PPS neoplasms.

(+/-)-trans-2-[3-methoxy-4-(4-chlorophenylthioethoxy)-5-(N-methyl-N- hydroxyureidyl)methylphenyl]-5-(3,4, 5-trimethoxyphenyl)tetrahydrofuran (CMI-392), a potent dual 5-lipoxygenase inhibitor and platelet-activating factor receptor antagonist

By incorporating an N-hydroxyurea functionality onto diaryltetrahydrofurans, a novel series of compounds was investigated as dual 5-lipoxygenese (5-LO) inhibitor and platelet-activating factor (PAF) receptor antagonist. These dual functional compounds were evaluated in vitro for 5-LO inhibition in RBL cell extracts and human whole blood, and PAF receptor antagonism in a receptor binding assay. PAF-induced hemoconcentration and arachidonic acid- and TPA-induced ear edema in mice were used to determine in vivo activities. The structure-activity relationship analysis to define a preclinical lead is presented. (+/-)-trans-2-[3-methoxy-4-(4-chlorophenylthioethoxy)-5-(N-methyl- N-h ydroxyureidyl)methylphenyl]-5-(3,4, 5-trimethoxyphenyl)tetrahydrofuran (40, CMI-392) was selected for further study. In the arachidonic acid-induced mouse ear edema model, 40 was more potent than either zileuton (a 5-LO inhibitor) or BN 50739 (a PAF receptor antagonist), and it demonstrated the same inhibitory effect as a physical combination of the latter two agents. These results suggest that a single compound which both inhibits leukotriene synthesis and blocks PAF receptor binding may provide therapeutic advantages over single-acting agents. The clinical development of compound 40 is in progress.

[Leiomyosarcoma of larynx and hypopharynx]

The laryngeal and hypopharyngeal smooth muscle tumors are very rare. One case of hypopharyngeal leiomyosarcoma and two cases of laryngeal smooth muscle tumors were reported: one angioleiomyoma, one leiomyosarcoma and one carcinoleiomyosarcoma. The patients usually present no characteristic symptoms in early stage and the clinical symptoms are similar to squamous cell carcinoma. It is difficult to make a correct diagnosis before operation. Treatment of first choice consists of primary radical resection including a large part of normal tissue. Early lymph node metastasis is rare. Precautary neck dissection is not indicated for subclinic cervical nodal disease. Radiotherapy may be taken as adjuvant or palliative measures.

Molecular cytogenetic characterization of Thinopyrum and wheat-Thinopyrum translocated chromosomes in a wheat-Thinopyrum amphiploid

The wheat-Thinopyrum amphiploid 'Agrotriticum # 3425' (AT 3425), which is highly resistant to Cephalosporium stripe, was identified to carry seven pairs of Thinopyrum chromosomes, three pairs of wheat-Thinopyrum translocated chromosomes and 18 pairs of wheat chromosomes. Fluorescence genomic in situ hybridization (FGISH), C-banding, sequential C-banding and FGISH, and denaturing polyacrylamide gel electrophoresis (SDS-PAGE) were used to characterize and identify the chromosomes. The Thinopyrum chromosomes in AT 3425 were designated as T1 through T7 based on their C-banding patterns. The FGISH and C-banding patterns of mitotic chromosomes in AT 3425 and meiotic chromosomes in the hybrid between AT 3425 and wheat cultivar 'Chinese Spring' (CS) revealed that wheat chromosomes 1D, 2B and 3D were involved in the three wheat-Thinopyrum chromosome translocations designated as (W-T)1, (W-T)2, and (W-T)3 respectively. The analysis of high-molecular-weight glutenin subunits in single seeds of AT 3425 confirmed the involvement of wheat chromosome 1D in the translocation (W-T)1. The designations 1DSx1DL-1TL, 2BSx2BL-2TL and 3DSx3DL-3TL were suggested for the wheat-Thinopyrum translocated chromosomes (W-T)1, (W-T)2 and (W-T)3 in AT 3425 respectively.

[Nonepithelial malignant neoplasms of the larynx and hypopharynx]

OBJECTIVES

Nonepithelial Malignant Neoplasms of the larynx and hypopharynx are rare. Their clinical features, diagnosis and treatment were discussed.

METHODS

From 1985 to 1996, 23 cases of nonepithelial malignant neoplasms of the larynx and 3 cases of hypopharynx were diagnosed. There were 21 males and 5 females. Age of the patients ranged from 16 to 65 years. Laryngeal tumours included 11 cases of sarcomas, 1 extramedullary plasmocytoma, 9 lymphomas and 2 malignant melanomas. Hypopharyngeal tumours included 1 leiomyosarcoma and 2 malignant melanomas. Extensive resection was the first treatment for 21 patients. Then, according to their histopathologic features, irradiation or/and chemotherapy were chosen.

RESULTS

Follow-up period was from 6 months to 10 years. There were 12 patients survived for 4 to 10 years, including 6 cases of laryngeal sarcomas, 2 supraglottic lymphomas, 2 malignant melanomas of the larynx, 1 malignant melanoma and 1 leiomyosarcoma of the hypopharynx.

CONCLUSIONS

Characteristics for these tumours were: 1. usually covered by intact mucosa; 2. laryngeal tumours rarely metastasize to the cervical lymph nodes; 3. difficulties in histopathological diagnosis, and immunohistochemistry is helpful to differentiation and determination.

[Neurilemmoma of the larynx with three case reports]

Neurilemmoma of the larynx is rare. We report three cases who were treated in our hospital in recent decade. The tumours mainly involves the aryepiglottic folds, the ventricular folds or extending to the pyriform fossa, uncommon being subglottic. It is believed that the most likely nerve of origin is the superior laryngeal nerve. Surgical approach was median laryngotomy for 2 cases and lateral pharyngotomy for 1 case.

Position 120-123, a potential active site of trichosanthin

Trichosanthin (TCS) is a type-I ribosome-inactivating protein (RIP) with wide spectrum of biological and pharmacological activities. In the present study, a potential site on the TCS molecule (position 120-123) is identified which may be important for the biological activities of TCS. By using site-directed mutagenesis, position 120-123 of TCS was either deleted or changed from Lys-Ile-Arg-Glu (hydrophilic) to Ser-Ala-Gly-Gly (hydrophobic). Deletion of these residues rendered a TCS molecule completely deprived of ribosome inactivating activity, while hydrophobic replacement caused 4000-fold decrease in ribosome inactivating activity. The abortifacient activity of these two mutants was retained with decreased potency. This implies that position 120-123 of the native TCS molecule plays a critical role in maintaining its biological activity.

PCR-SSCP of rDNA for the identification of Trichinella isolates from mainland china

A polymerase chain reaction (PCR)-based single strand conformation polymorphism (SSCP) analysis of the expansion segment 5 (domain IV) of the large subunit of ribosomal DNA was employed to characterize seven isolates of Trichinella from China (A-G), including six of pig origin from regions in Dengxian (A), Tianjin (B), Harbin (D), Baoshan (E), Xinye (F) and Xian (G), and one of canine origin from Changchun (C). Isolates A, D, E, F and G were classified as Trichinella spiralis based on SSCP patterns, while the patterns for isolates B and C were consistent with those of Trichinella nativa or Trichinella T6. The results were supported by random amplified polymorphic DNA (RAPD) analysis using five decamer primers and were in accordance with ecological information for the isolates. Single strand conformation polymorphism results also allowed the direct display of mutational sequence variation in the expansion segment among the five isolates of T. spiralis from China, indicating its usefulness for studying population variation within that species.

Expression of neuron-specific beta-III tubulin during olfactory neurogenesis in the embryonic and adult rat

The olfactory neuroepithelium retains the unique capacity to produce a new set of mature neurons every three to four weeks from a precursor population situated at the base of the epithelium. It is not known however, whether developing olfactory neurons in the adult rat follow the same program that is initiated embryonically. By tracking the expression of beta-III tubulin (by immunoreactivity to TuJ-1, an isoform-specific antibody) throughout embryogenesis, we have demonstrated a commitment to the olfactory neuron lineage in a subset of cells in the embryonic olfactory placode and followed their development into adulthood. We have also shown that this developmental pattern of beta-III tubulin expression is recapitulated in neurons undergoing a synchronized neurogenic response to either physical or chemical lesion in the adult neuroepithelium. The embryonic expression pattern reported here is similar to, but earlier than that reported for other markers of developing neurons, such as growth-associated protein-43 and neural cell adhesion molecule. The results of these studies suggest the retention of a conserved neurogenic program from embryonic to adult life in the olfactory neuron and, in addition, support the use of a readily accessible system such as the regenerating olfactory neuroepithelium as an alternative means of studying genes which may be crucial to normal neuronal development.

Mismatch-sensitive hybridization detection by peptide nucleic acids immobilized on a quartz crystal microbalance

A quartz crystal microbalance DNA hybridization biosensor, based on thiol-derivatized peptide nucleic acid (PNA) probes, offers unusual in situ differentiation of single-base mismatches. A large excess of a single-base mismatch oligonucleotide has no effect on the frequency response of the target. Such remarkable distinction between perfect matches and mismatches is illustrated by the detection of a common mutation in the p53 gene. The greater specificity of the new mass-sensitive indicatorless hybridization device over those of analogous PNA-based carbon electrodes is attributed to the formation of a PNA monolayer and the use of a hydrophilic ethylene glycol linker. The improved specificity is coupled to very fast (3-5 min) hybridization in a low-ionic-strength medium.

Expression cloning of a mammalian amino acid transporter or modifier by complementation of a yeast transport mutant

A cDNA clone named L21 was isolated from L6 rat muscle cells by complementation of a yeast proline transport mutant. L21 cDNA has 2,268 bp and codes for a peptide of 228 amino acids with four potential transmembrane domains. The amino acid sequence of L21 shows no homology to any known proteins. Expression of L21 cDNA enables the mutant yeast to grow in proline as the sole nitrogen source and to transport proline, alpha-aminoisobutyric acid (AIB) and leucine. The Km for proline is about 1.0 mM. The substrate specificity of L21 expressed in yeast shows no striking similarity to known mammalian amino acid transporters.

Genes regulated by androgen in the rat ventral prostate

Genes that are regulated by androgen in the prostate were studied in the rat. Four of the less than 10 genes that are down-regulated by androgen in the ventral prostate of a 7-day castrated rat were identified; their mRNAs decayed with identical kinetics. Twenty-five of the estimated 56 genes that are up-regulated by androgen in the castrated prostate have been isolated. The up-regulated genes fall into two kinetic types. Early genes are significantly up-regulated by 6.5 hr whereas the delayed genes respond mainly after 24 hr from the time of androgen replacement. These androgen-response genes are also regulated in the prostate by castration, indicating that these genes could play important roles in androgen-induced regrowth and/or castration-induced regression of the prostate during hormonal manipulation. A survey of the tissue specificity showed that the androgen-response gene expression program in the prostate is mainly prostate-specific. Total RNA Northern blot analysis detects the expression of about 16 up-regulated genes and 3 down-regulated genes in the prostate only. Four up-regulated genes and one down-regulated gene are regulated by androgen in both the prostate and seminal vesicles but not in other organs. The expression of the remaining androgen-response genes is not limited to the prostate but is only responsive to androgen in the prostate. This survey of the androgen-response gene expression program provides insights into the molecular and cellular mechanisms of androgen action in the prostate.

Nucleic-acid immobilization, recognition and detection at chronopotentiometric DNA chips

Wide-scale DNA testing requires the development of fast, small, easy-to-use biosensing devices. Various synthetic oligonucleotides and DNA have thus been immobilized onto microfabricated thick-film carbon transducers for performing several new nucleic-acid assay protocols. These include hybridization detection of nucleic acid sequences, determination of small molecules (drugs, pollutants) based on their collection into the dsDNA layer or via monitoring their effect upon the intrinsic DNA oxidation signal, and direct adsorptive stripping measurements of ultratrace levels of nucleic acids. Transduction of these DNA recognition processes is accomplished by a new highly-sensitive constant-current stripping chronopotentiometric operation. Comparison to traditional electrodes indicates that the biosensing performance is not compromised by the use of mass-producible disposable transducers. Such thick-film DNA biosensors have been coupled to a compact, user-friendly, hand-held analyzer. Applicability for the detection of sequences from M. tuberculosis and HIV-1 DNAs is illustrated. Such activity in the author's laboratory, aimed at developing DNA-coated screen-printed electrodes, is reviewed.

Characterization of colorectal-cancer-related cDNA clones obtained by subtractive hybridization screening

In an attempt to seek out new factors that are related to colorectal carcinogenesis at the molecular level, subtractive hybridization between cDNA of normal mucosal tissues and mRNA of colorectal carcinoma tissues was performed. Subsequent screenings of the cDNA libraries, constructed from normal mucosal tissues, using the "subtractive probes" generated a total of 46 clones that were expressed in normal mucosa but were either expressed at a significantly reduced level or not expressed at all in cancer tissues. Partial nucleotide sequences of all of these cDNA clones were determined, and sequence homology analyses were performed with the Genbank database. Of the 46 cDNA samples, 44 contained substantial sequence homologies with 32 immunoglobulin gene fragments, a helix-loop-helix basic phosphoprotein gene, an acidic ribosomal phosphoprotein P2 gene, a BLR1 gene for Burkitt's lymphoma receptor 1 gene, D5S419 DNA segment containing (C-A) repeats, a glucokinase (GCK) gene, a Na+, K+-ATPase alpha-subunit gene, a histocompatibility system HLA-DR heavy-chain gene, a dystrophic gene, a mucin (MUC2) gene, a mu-glutathione S-transferase gene, a Menkes disease protein gene, and a 40-kDa keratin intermediate filament precursor gene. The remaining two cDNA clones (now registered under GenBank accession numbers U17714 and U20428) showed few (less than 60%) sequence homologies with any known sequences in the GenBank database and, therefore, may represent novel genes whose expression was down-regulated in human colorectal carcinomas. The possible clinical significance of these findings and the involvement of these two genes in the carcinogenesis of colorectal as well as other cancers are being investigated.

Correlation between retinal fluorescein angiography and blood viscosity and other factors in patients with primary open angle glaucoma

OBJECTIVE

To investigate the correlation among retinal fluorescein angiography, blood viscosity, and other factors in patients with open angle glaucoma (POAG).

METHODS

Multiple step regression analysis was made to investigate the correlation between each of the following blood vessel filling times: the arm-choroid (A-CT), arm-retinal artery (A-AT), and retinal artery-venous (A-VT) of the fundus fluorescein angiography (FFA) in 122 eyes with POAG and each of the following related factors in hemorrheology: whole blood apparent viscosity at low, medium and high shear rates, plasma viscosity and hematocrit. Also, the same analysis was applied to investigate the correlation between each of the A-AT, A-VT of the FFA in 70 eyes with POAG and the following factors: systolic blood pressure, diastolic blood pressure, age and whole blood apparent viscosity at low shear rate.

RESULTS

The whole blood apparent viscosity at low shear rate was closely related to A-CT and A-AT, while hematocrit was closely related to A-VT of the FFA. The whole blood apparent viscosity at low shear rate and age, especially the whole blood apparent viscosity, was closely related to A-AT, A-VT of the FFA.

CONCLUSION

Blood viscosity can affect the filling times of the FFA in POAG.

[Determination of minor flavor components in Chinese spirits by direct-injection technique with capillary columns]

Chinese spirits are among the best-known distilled alcoholic beverages in the world. Because of the longer multiple-strain fermentation, Chinese spirits are richer than yeast fermented western liquors in fragrance and mellow. The complex nature of Chinese spirits often makes it difficult to separate, identify and quantify major and minor flavor components. Among the several analytical methods for flavor components in Chinese spirits developed in recent years, the direct-injection technique using capillary columns is by far the best. In this study of direct injection with crosslinked PEG 20M, HP-INNOWax and bonded SGE BP21 columns, up to 68 flavor components including alcohols, organic acids, esters, acetals, carbonyl and heterocyclic compounds were identified with fine-tuning separation and followed by GC/MS to identify. The gas chromatographic separation of flavour components of Maotai Liquor by the method on PEG 20M, SGE BP21 and HP-INNOWax are shown. The compounds of the numbered peaks in the chromatograms are listed. Three compounds of, ie., amyl acetate, t-pentanol and 2-ethyl butyric acid, were used as internal standards to minimize discrimination in quantitative determination. The operation procedures for these tests were provided. The application identities of three capillary columns for the analysis of minor flavor components with direct injection were summarized respectively.

Comparison of fusion phage libraries displaying VH or single-chain Fv antibody fragments derived from the antibody repertoire of a vaccinated melanoma patient as a source of melanoma-specific targeting molecules

A single-chain Fv (scFv) fusion phage library derived from random combinations of VH and VL (variable heavy and light chains) domains in the antibody repertoire of a vaccinated melanoma patient was previously used to isolate clones that bind specifically to melanoma cells. An unexpected finding was that one of the clones encoded a truncated scFv molecule with most of the VL domain deleted, indicating that a VH domain alone can exhibit tumor-specific binding. In this report a VH fusion phage library containing VH domains unassociated with VL domains was compared with a scFv fusion phage library as a source of melanoma-specific clones; both libraries contained the same VH domains from the vaccinated melanoma patient. The results demonstrate that the clones can be isolated from both libraries, and that both libraries should be used to optimize the chance of isolating clones binding to different epitopes. Although this strategy has been tested only for melanoma, it is also applicable to other cancers. Because of their small size, human origin and specificity for cell surface tumor antigens, the VH and scFv molecules have significant advantages as tumor-targeting molecules for diagnostic and therapeutic procedures and can also serve as probes for identifying the cognate tumor antigens.