Prognostic value of p53, glutathione S-transferase pi, and thymidylate synthase for neoadjuvant cisplatin-based chemotherapy in head and neck cancer

Neoadjuvant cisplatin-based chemotherapy has been widely used in the last decade for organ preservation or unresectable disease in advanced stage head and neck cancer. We examined the expression of a series of tumor markers that have been associated with chemotherapy resistance in pretreatment biopsies from 68 patients who received cisplatin-based neoadjuvant chemotherapy at either of two institutions. Patients received either cisplatin/5-fluorouracil (n = 49) or cisplatin/paclitaxel (n = 19). Expression of p53, glutathione S-transferase pi (GSTpi), thymidylate synthase (TS), c-erbB2, and multidrug resistance-associated protein was examined by immunohistochemistry. Expression of glutathione synthetase mRNA was measured by in situ hybridization. The overall response rate for cisplatin-based neoadjuvant treatment was 79%. The expression of several of the tumor markers was associated with resistance to neoadjuvant treatment, but none reached statistical significance. Overall survival (OS) was strongly correlated with the absence of p53 expression. The OS at 3 years was 81% in the p53-negative group, whereas it was 30% in the p53-positive group for patients treated with neoadjuvant chemotherapy (P < 0.0001). Expression of GST pi and TS was also significantly correlated with decreased OS after neoadjuvant treatment. At 3 years, the OS rate was 82% in the low GSTpi score group, compared to 46% in the high GSTpi score group (P = 0.0018). In the TS-negative group, the 3-year OS rate was 71% compared with 40% in the TS-positive group (P = 0.0071). We conclude that p53, GSTpi, and TS may be clinically important predictors of survival in patients receiving neoadjuvant chemotherapy for head and neck cancer.

Dynamics of astrocyte adhesion as analyzed by a combination of atomic force microscopy and immuno-cytochemistry: the involvement of actin filaments and connexin 43 in the early stage of adhesion

We observed the time-dependent morphological alteration of astrocytes during their adhesion by atomic force microscopy (AFM) and investigated the relationships between this morphological alteration and the localization of actin filaments and connexin 43 by immunocytochemistry. The fine processes observed as fine ridge-like structures by AFM were closely concerned with actin filaments by immunocytochemistry. During the adhesion of astrocytes, actin filaments appeared to be aligned regularly beyond the borders among different cells. Detectable connexin immunoreactivity was changed in the following regions: 1) the tips of fine cell processes and the cell margin when astrocytes started to adhere; 2) the border of cells when astrocytes tightly adhered; and 3) non-specific sites when astrocytes became a cluster. In the former two cases, the immunopositive spots for connexin were observed to colocalize with the tips of cell processes with actin filaments. These results strongly suggest that connexin associated with actin filaments at the tip of cell processes plays an important role in the early stage of the adhesion of astrocytes. These observations afford valuable clues for understanding the glial communication.

Ankle arthrodesis in rheumatoid arthritis using an intramedullary nail with fins

We describe an intramedullary nail with fin-like longitudinal ridges that we have developed for arthrodesis of the ankle in rheumatoid arthritis. Four fins with sharp tips were attached to the distal part of a cylindrical nail to stabilize the tibiotalar and subtalar joints. We used this nail in 15 feet of 15 patients with rheumatoid arthritis who were followed for an average of 34.9 months. Postsurgery, 13 patients were allowed to bear weight immediately, as tolerated, without immobilization. By 3 weeks, these patients were able to bear weight fully. Solid fusion of the ankle joint in an acceptable position and good clinical results were obtained in all patients. The only complications were two cases of delayed wound-healing.

Longterm outcome of total joint arthroplasty in nonambulatory patients with rheumatoid arthritis

OBJECTIVE

To assess the outcome of minimum 10 year followup of total joint arthroplasty (TJA) in nonambulatory patients with rheumatoid arthritis (RA).

METHODS

TJA was performed in 40 nonambulatory patients with RA who satisfied the following criteria: (1) strong motivation; (2) good relationship with our medical staff; (3) no marked cervical cord lesion: (4) absence of severe systemic complications. These included 38 women and 2 men whose average age at the initiation of TJA was 58.8 years. The duration of time between loss of walking ability and surgery was 2 months to 5 years. Average hospitalization time was 4.5 months. Followup after the last surgery was 10 to 18 years.

RESULTS

One year after the last surgery, 28 of the 40 patients could walk outdoors again, 11 indoors, and one was still unable to walk. By 5 years after surgery, 9 patients had died of diseases unrelated to surgery. Of the remaining 31 patients, 19 could walk outdoors, 10 indoors, and 2 could not walk. Deterioration of walking was observed in 13 patients (41.9%) compared with one year after surgery. By 10 years after surgery, 32 patients had died of diseases unrelated to surgery, 4 could walk outdoors, 4 indoors. Of these, 4 patients (50%) had worsened in walking ability compared with one or 5 years after surgery. Major complications of TJA were observed in 12 patients. These were femoral neck fractures in 3, supracondylar femoral fractures in 3, loosening of the acetabulum socket in 4, loosening of the femoral hip prosthesis in 2.

CONCLUSION

TJA should be a useful treatment for restoration of walking in nonambulatory patients with RA. However, even after TJA, walking ability deteriorated in about half of the patients as the duration of followup observations exceeded 5 years.

[Glutathione and cisplatin resistance in head and neck cancer]

Since glutathione is considered to be an important mediator of cancer cell resistance to cisplatin-based chemotherapy, we investigated glutathione in head and neck cancer by both laboratory and clinical investigations.

MATERIALS AND METHODS

Intracellular glutathione concentration was measured in 7 different cell lines that originated from head and neck cancer and was correlated to their IC50 to cisplatin. Expression of gamma-glutamyl cysteine (gamma-GCS) mRNA was assessed by in situ hybridization and gamma-glutamyl transpeptidase (GGT) expression was assessed with immnunohistochemistry of 56 biopsy specimens from 51 clinical cases. Both these enzymes are important for maintenance of intracellular glutathione concentration.

RESULTS

Intracellular glutathione concentration was strongly correlated with cisplatin IC50 (R2 = 0.814, P = 0.0012), suggesting that glutathione plays a major role in cisplatin resistance in head and neck cancer. High gamma-GCS expression was observed in 27 out of 47 specimens (57%), but the response rate to chemotherapy (63%) in the high expression group was not significantly different to the low expression group (P = 0.20). High GGT expression was observed in 32 out of 53 specimens (60%), but the response rate in the high GGT group was not significantly different to that of the GGT group.

CONCLUSION

Although intracellular glutathione plays an important role in resistance to cisplatin in head and cancer cell lines, we failed to prove that two enzymes that contribute to the maintenance of intracellular glutathione concentration are predictive factors for the response to cisplatin-based chemotherapy. Since clinical cases are further complicated by interactions of the immune system, involvement of a variety of genes related to oncogenesis, and accompanying drugs such as 5FU, it is very difficult to determine a single factor to predict the response to cisplatin. More precise analysis is necessary to determine how head and neck cancer resists cisplatin.

Cervical curvature in acute whiplash injuries: prospective comparative study with asymptomatic subjects

The cervical curvature of 488 patients with acute whiplash injury was prospectively studied by comparison with 495 asymptomatic healthy volunteers. Plain radiography of the cervical spine in the neutral position was evaluated qualitatively. No significant difference was noted in frequencies of non-lordotic cervical curvature and local angular kyphosis between acute whiplash injury patients and asymptomatic subjects. No significant association was apparent between clinical symptoms and cervical curvature. These results suggest that non-lordotic cervical curvature and angular kyphosis in acute whiplash injury patients constitute normal variants rather than pathological findings.

[Critical care for organ failure]

We retrospectively studied the critical care regimen for multiple organ failure (MOF) in 141 surgical MOF patients treated in the intensive care unit of Chiba University Hospital between January 1988 and April 1998. Patients with gut failure received parenteral instead of enteral nutrition for various reasons such as concomitant ileus. Of the patients with respiratory failure. 138 were placed on a ventilator and 6 received percutaneous cardiopulmonary support. Continuous hemodiafiltration (CHDF) was performed in 98 patients with renal failure. Plasma exchange was carried out in 13 patients with liver failure. Of these patients, 62 (44%) survived. Colloid osmotic pressure was used as an indicator for fluid therapy. For prophylaxis against bacterial translocation, we performed selective digestive decontamination. Recently blood purification methods, particularly CHDF, have become common in the critical care setting. CHDF is efficacious not only as continuous renal replacement therapy but also as a humoral mediator modulator and is currently the first-choice method for blood purification in critical care. In conclusion, there have been many advances in the critical care of patients with organ failure. Multidisciplinary treatment, including artificial support for failing organs, is necessary for the survival of these patients.

Cellular injury score for multiple organ failure severity scoring system

BACKGROUND

Cellular Injury Score (CIS) is an index of cellular injury, being calculated from three parameters of intracellular metabolism: arterial ketone body ratio, osmolality gap, and blood lactate.

METHODS

The usefulness of CIS as a severity scoring system for patients with multiple organ failure was prospectively evaluated in 157 consecutive patients with MOF (58 survivors, 99 nonsurvivors).

RESULTS

CISs in nonsurvivors were significantly higher compared with those in survivors throughout the clinical courses. CIS was significantly correlated with the number of failing organs and mortality rate. The optimal cutoff point of CIS from receiver operating characteristics curve analysis was 4 for the maximal value during the clinical course. The changes in CIS well reflected the severity of injury in survivors and nonsurvivors who died within 2 weeks.

CONCLUSION

CIS could be a useful index for mortality risk prediction and is potentially applicable as a severity scoring system for individual patients with MOF.

Long-term results of Yoshino total knee arthroplasties in rheumatoid arthritis

A review was made of 267 Yoshino total knee arthroplasties performed on 184 patients with rheumatoid arthritis between June 1978 and December 1983. The average duration of follow-up was 14.3 years. Of these patients 46.7% died during the follow-up period. The main causes of death were cardiac disease, respiratory disease and renal disease. According to the Japanese Orthopaedic Association (JOA) knee rating system, JOA scores decreased significantly with time after surgery, but remained significantly higher than the preoperative scores. The flexion angle after surgery had decreased compared with the preoperative flexion angle and decreased further 3 years after surgery and later. The cumulative survival rate was 88.6%. This rate was mainly affected by postoperative infection and aseptic loosening of the tibial components.

[Silicon of the medium in the postoperative maxillary cyst]

As part of a study on chronic inflammatory disease of the mucous membrane, silicon of the medium in postoperative maxillary cysts and in other cysts was measured, and following results were obtained. Silicon concentrations of the medium in the postoperative maxillary cysts and in the postoperative ethmoidal cysts were 34.5 ppm and 42.9 ppm (geometrical mean) respectively, and they were higher than in other primary cysts such as frontal cyst, nasal vestibular cyst, and dental cyst. The silicon content of the medium in the postoperative maxillary cyst varied with the water content of the medium; the lower the water content the higher was the silicon content and the relationship was expressed by the following equation. log S = 7.43 + 7.14 log d-6.14 log w, where S = Si (mcg), d = dry weight (g.) and w = wet weight (g.). The high concentration of silicon in the postoperative cyst was considered to be due to the large amount of silicon transudate from the surrounding fibrous tissue through a highly damaged or missing epithelial wall of the cyst.

MRI of cervical intervertebral discs in asymptomatic subjects

We studied degenerative changes in the cervical intervertebral discs of 497 asymptomatic subjects by MRI and evaluated disc degeneration by loss of signal intensity, posterior and anterior disc protrusion, narrowing of the disc space and foraminal stenosis. In each subject, five disc levels from C2-C3 to C6-C7 were evaluated. The frequency of all degenerative findings increased linearly with age. Disc degeneration was the most common observation, being present in 17% of discs of men and 12% of those of women in their twenties, and 86% and 89% of discs of both men and women over 60 years of age. We found significant differences in frequency between genders for posterior disc protrusion and foraminal stenosis. The former, with demonstrable compression of the spinal cord, was observed in 7.6% of subjects, mostly over 50 years of age. Our results should be taken into account when interpreting the MRI findings in patients with symptomatic disorders of the cervical spine.

MRI of cervical intervertebral discs in asymptomatic subjects

We studied degenerative changes in the cervical intervertebral discs of 497 asymptomatic subjects by MRI and evaluated disc degeneration by loss of signal intensity, posterior and anterior disc protrusion, narrowing of the disc space and foraminal stenosis. In each subject, five disc levels from C2-C3 to C6-C7 were evaluated. The frequency of all degenerative findings increased linearly with age. Disc degeneration was the most common observation, being present in 17% of discs of men and 12% of those of women in their twenties, and 86% and 89% of discs of both men and women over 60 years of age. We found significant differences in frequency between genders for posterior disc protrusion and foraminal stenosis. The former, with demonstrable compression of the spinal cord, was observed in 7.6% of subjects, mostly over 50 years of age. Our results should be taken into account when interpreting the MRI findings in patients with symptomatic disorders of the cervical spine.

Orbital high resolution magnetic resonance imaging with fast spin echo in the acute stage of Leber's hereditary optic neuropathy

Some evidence suggests that the primary locus of the lesion in Leber's hereditary optic neuropathy (LHON) may be intraocular rather than retrobulbar. To clarify this issue, the condition of the retrobulbar portion of the optic nerve was evaluated in patients with the acute stage of LHON. High resolution MRI with fast spin echo sequences of the optic nerve complex in the orbit was carried out. Five patients with acute stage LHON were compared with seven patients with acute stage optic neuritis. On T2 weighted fast spin echo MRI, signal changes did not appear in the retrobulbar optic nerve complex in acute stage LHON. By comparison, patients with optic neuritis showed pronounced high signals in the optic nerve. Subsequent orbital MRI in the atrophic stages of the same patients with LHON showed an increase in signal intensity in the optic nerve toward the orbital apex in both eyes. The present results support the hypothesis that a primary lesion in LHON may be intraocular.

A case of spontaneous femoral neck fracture associated with multicentric reticulohistiocytosis: oversecretion of interleukin-1beta, interleukin-6, and tumor necrosis factor alpha by affected synovial cells

We describe a case of left femoral neck fracture associated with multicentric reticulohistiocytosis (MR). Biopsy specimens from a skin nodule and from synovial tissue showed histiocytic multinucleated giant cells (MR cells) that are characteristic of MR. A surgical specimen from the resected femoral head revealed that multinucleated giant cells and mononuclear cells invaded the marginal subchondral bone, without evident pannus. These cells also infiltrated into the fracture site, with bone resorption by activated osteoclasts. Immunohistochemical studies of synovium from the left hip joint showed positive staining for interleukin-1beta (IL-1beta), IL-6, and tumor necrosis factor alpha, and abundant cytokine production by cultured synovial cells was demonstrated. These findings suggest that the subchondral invasion and intramedullary infiltration by MR cells caused articular destruction and/or fracture as a result of oversecretion of the cytokines.

Prediction of consistency of meningiomas with preoperative magnetic resonance imaging

BACKGROUND

The consistency of a meningioma is one of the important factors in determining the surgical outcome. If the surgeon is aware of the consistency of a meningioma preoperatively, the surgical plans will be influenced. A few papers have described the correlation between consistency of meningiomas and their magnetic resonance imaging (MRI) findings. However, prediction of consistency with MRI is still difficult. We have tried to predict the consistency of meningiomas with MRI findings more precisely.

METHODS AND RESULTS

Fifty patients diagnosed as having intracranial meningiomas were studied with 1.5 Tesla MRI. We compared the MRI findings with tumor consistency. The intensities of the tumors were categorized into three grades (low, iso, and high) compared to that of the gray matter. T1-weighted images had no specifics, but T2-weighted images and proton density images were useful for the prediction of tumor consistency. Hyperintensity on protein density (PD) and T2-weighted images was a sign of a soft tumor.

CONCLUSION

We presume that T2 and PD are useful for predicting consistency of meningiomas, and their water content is one of the main factors in their consistency. Histology may be one of the factors helpful in defining the consistency of a tumor. In this series, we found no relationship between histology and MRI findings, nor between histology and consistency. If the meningioma is believed to be hard, preoperative endovascular embolization is beneficial, which will induce necrosis of the meningioma and make it soft enough to be removed more easily and safety.

Efficacy and limitation of apheresis therapy in critical care

Apheresis therapy such as plasma exchange and plasma adsorption has become therapeutic tools in critical care. The indications for apheresis therapy in ICU patients include fulminant hepatic failure, thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS), autoimmune disease, and sepsis. During the past 11 years, 150 patients with various kinds of critical illnesses were treated with apheresis therapy in our ICU, and the overall survival rate was 50%. Apheresis therapy is especially useful in the treatment of a patient with fulminant hepatic failure because liver transplantation is seldom performed in Japan; therefore, the patient should be treated with artificial liver support. When plasma exchange is performed on the critically ill, continuous hemodiafiltration should be performed simultaneously to overcome the adverse effects of plasma exchange such as hypernatremia, metabolic alkalosis, and abrupt changes in colloid osmotic pressure and to enhance the removal rate of the causative middle molecular weight substances of hepatic failure or hepatic coma.

Patient with primary tonsillar and gastric syphilis

A male patient with syphilitic lesions in the tonsil and stomach is presented. The patient was infected while practising oral sex with heterosexual friends. He complained of nausea and snoring; his left tonsil was enlarged. Spirochetes were detected in a smear preparation from the left tonsil. As a gastric lesion, initially believed to be cancer, appeared to result from spirochete ingestion, the case is considered to represent primary syphilis. After antibiotic therapy with ampicillin, the left tonsil returned to normal size and gastric changes were no longer evident endoscopically. Gastroscopy should be considered if syphilis of the tonsil is observed, particularly when gastrointestinal symptoms are present. Both the oral and the gastric lesion can be mistaken for malignant neoplasm.

Evidence of presentation of multiple HIV-1 cytotoxic T lymphocyte epitopes by HLA-B*3501 molecules that are associated with the accelerated progression of AIDS

We recently showed HLA-B35-restricted CTL activity for 10 HIV-1 epitopes in PBL from two HIV-1-infected individuals. In the present study, we established CTL clones specific for nine of these HIV-1 epitopes to confirm these HLA-B35-restricted epitopes. The specific CTL clones effectively killed the HLA-B*3501-positive target cells infected with the HIV-1 vaccinia recombinant virus. These results confirmed that nine HIV-1 CTL epitopes are presented by HLA-B*3501 molecules. The CTL activity specific for four Pol and two Nef epitopes was induced in the peptide-stimulated PBL from three or more of seven HIV-1-infected individuals, indicating that these six are common epitopes. Eight were considered strong epitopes because the specific CTL activity was detected in the cultured PBL that was once stimulated with peptides. Thus, the present study excluded the possibility that the disability of the presentation of HIV-1 epitopes by HLA-B35 molecules is associated with the accelerated progression of AIDS in HLA-B35-positive individuals. Analysis of mutated epitopes found in an HIV-1 type B strain using the CTL clones revealed that most mutated epitopes partially or markedly affect the recognition of CTL clones. Of 19 mutations that affected recognition of the CTL clones, 7 reduced peptide-HLA-B*3501 binding, while 12 affected TCR recognition. These results indicate that natural mutations of HLA-B35-restricted HIV-1 CTL epitopes affect the recognition of CTL by mechanisms that reduce both peptide binding and TCR recognition.

Evidence of presentation of multiple HIV-1 cytotoxic T lymphocyte epitopes by HLA-B*3501 molecules that are associated with the accelerated progression of AIDS

We recently showed HLA-B35-restricted CTL activity for 10 HIV-1 epitopes in PBL from two HIV-1-infected individuals. In the present study, we established CTL clones specific for nine of these HIV-1 epitopes to confirm these HLA-B35-restricted epitopes. The specific CTL clones effectively killed the HLA-B*3501-positive target cells infected with the HIV-1 vaccinia recombinant virus. These results confirmed that nine HIV-1 CTL epitopes are presented by HLA-B*3501 molecules. The CTL activity specific for four Pol and two Nef epitopes was induced in the peptide-stimulated PBL from three or more of seven HIV-1-infected individuals, indicating that these six are common epitopes. Eight were considered strong epitopes because the specific CTL activity was detected in the cultured PBL that was once stimulated with peptides. Thus, the present study excluded the possibility that the disability of the presentation of HIV-1 epitopes by HLA-B35 molecules is associated with the accelerated progression of AIDS in HLA-B35-positive individuals. Analysis of mutated epitopes found in an HIV-1 type B strain using the CTL clones revealed that most mutated epitopes partially or markedly affect the recognition of CTL clones. Of 19 mutations that affected recognition of the CTL clones, 7 reduced peptide-HLA-B*3501 binding, while 12 affected TCR recognition. These results indicate that natural mutations of HLA-B35-restricted HIV-1 CTL epitopes affect the recognition of CTL by mechanisms that reduce both peptide binding and TCR recognition.

Recovery of full flexion after total knee replacement in rheumatoid arthritis--a follow-up study

Twenty-three of 327 patients with rheumatoid arthritis (38 out of 509 knees) had primary Yoshino-Shoji total knee replacements between 1984 und 1990 and were able to squat fully in the Japanese style after the procedure. Seven had died of conditions unrelated to their operations. Of the remaining 16, 5 were able to squat fully at follow-up; 2 were unable to do so, but had full passive flexion; 9 were unable to squat and did not have full flexion. The cumulative survival rates of patients able to squat were 82.2%, 65.7% and 47% at 2, 5 and 8 years after operation. At follow-up, 3 were able to walk out of doors for less than 30 min, 6 for 30 min or more and in 7 walking was unlimited. These results suggest that daily exercises are important in maintaining full flexion. The absence of complications may be due low body weight and limited activity due to the disease. patients with rheumatoid arthritis and low body weight can be encouraged to regain full flexion after total knee replacement if they wish to do so.

MR angiography of intracranial aneurysms: a comparison of 0.5 T and 1.5 T

The objective of this paper is to compare the diagnostic efficacy of 3 DFT time-of-flight MR angiography (MRA) at middle-field-strength and high-field-strength in diagnosis of intracranial aneurysms. Thirty-one patients, including 26 patients with angiographically confirmed intracranial aneurysms (n = 28), underwent MRA at 0.5 and 1.5 T. Images were interpreted by six trained observers who were blinded to diagnosis. Twelve projections of MRA of the circle of Willis, by maximum-intensity projection algorithm, were reviewed using continuous confidence-judgement scales. It was found that MRA at 1.5 T was more sensitive than that at 0.5 T in detection of aneurysms. The sensitivity of six observers ranged between 50 and 64% (mean 56%) at 0.5 T, and between 61 and 86 86% (mean 75%) at 1.5 T. In the smaller aneurysms less than 5 mm, the differences between the units became greater. The sensitivity for small aneurysms ranged from 23 to 54% (mean 32%) at 0.5 T, and from 31 to 69% (mean 58%) at 1.5 T. Our conclusion was that high field strength confers higher accuracy in the detection of intracranial aneurysms with MRA with current-generation MR imagers.

Intracranial vascular stenosis and occlusion: MR angiographic findings

PURPOSE

To investigate whether obtaining axial source images from three-dimensional Fourier transform (3DFT) time-of-flight MR angiography improves the detection of intracranial vascular stenosis and occlusion if added to maximum-intensity projection (MIP) images.

METHODS

The angiograms of 103 patients who had MR angiography for evaluation of possible intracranial vascular disease were reviewed retrospectively in a quantitative and nonquantitative fashion. Diameters of vessels on MR angiograms were measured quantitatively by two reviewers using a magnifying loupe and compared with the results from conventional angiograms. Degrees of stenoocclusive disease were categorized into five classes; an artery with stenosis of 50% or greater was considered to be diseased. Another five observers also reviewed the MIP images with and without source images in a blinded fashion by means of nonquantitative visual inspection.

RESULTS

In all, 23 stenoocclusive lesions of 50% or greater were available for review. In the quantitative analysis, with MIP images alone, 14 (78%) of 18 moderate and severe stenoses and four (80%) of five occlusions were identified correctly. The addition of the source images increased the sensitivity to 100% for moderate and severe stenoses and to 100% for occluded vessels. In the visual inspection study, however, no statistically significant differences were found between interpretations of MIP images alone and those of MIP images in combination with source images.

CONCLUSION

In the quantitative study, interpretation of source images rather than MIP images reduced the tendency to overestimate stenosis seen with MR angiography and improved the sensitivity for detecting stenosis of 50% or greater. There was a discrepancy between the quantitative study and visual inspection. Experienced observers had a tendency to underestimate the degree of stenosis.

Refined peptide HLA-B*3501 binding motif reveals differences in 9-mer to 11-mer peptide binding

HLA-B*3501 is associated with subacute thyroiditis and fast progression of AIDS. An important prerequisite to investigate the T-cell recognition of HLA-B*3501-restricted antigens is the characterization of peptide-HLA-B*3501 interactions. In this study, peptide-HLA-B*3501 interactions were determined in quantitative peptide binding assays. The results were statistically analyzed to evaluate the influence of both anchor and nonanchor positions and the predictability of peptide binding. The binding data demonstrated that all anchor residues at position 2 and the C-terminus found in 9-mers functioned equally as anchors in 10-mers and 11-mers. These minimum requirements of peptide binding were refined by assessing positive and negative effects of nonanchor residues. Aliphatic hydrophobic residues at positions 3, 5, and 8 of 10-mers and position 3 of 11-mers significantly enhanced HLA-B*3501 binding. Similar effects rendered aromatic, bulky residues, acidic or polar residues of 11-mers at position 1 as well as at positions 4, 8, and 10, respectively. Negative effects were observed for residues carrying positively charged side-chains at position 7 of 11-mers. The refined HLA-B*3501 peptide binding motifs enhanced the identification of potential T-cell epitopes. The disparity between positive effects at the middle and C-terminal part (positions 5 - 8 and 10) of 11-mers and shorter peptides supports the extrusion of 11-mer residues at positions 5, 6, and 7, away from the HLA-B*3501 binding cleft.

Antianginal effect of RS-5773, a diltiazem congener, in the methacholine-induced anginal model in rats

The antianginal effect of RS-5773 ((2S,3S)-3-acetoxy-8-benzyl-2,3-dihydro-5-[2-(dimethylamino)- ethyl]-2-(4-methoxyphenyl)-1,5-benzothiazepine-4-(5H)-one hydrochloride), a newly developed benzothiazepine derivative, was evaluated in an angina model rat. Close-coronary artery injections of methacholine in anesthetized rats evoked ischemic electrocardiographic (ECG) changes (S wave elevation of about 0.6 mV). The ECG changes produced by methacholine were reproducible for as long as 6 hr. Intravenous and intraduodenal administration of RS-5773, diltiazem or clentiazem produced dose-dependent suppressions of the ischemic ECG changes. RS-5773 exceeded the other two agents both in the maximum suppressive effect on S wave elevation and in the duration of action after intravenous administration. The antianginal potency expressed as AUC (area under the curve), i.e., the percent suppression of S wave elevation integrated over time, revealed that RS-5773 was 16 times and 7 times more potent than diltiazem and clentiazem, respectively. A similar order of potency difference was observed after intraduodenal administration, and RS-5773 sustained its effect for about 6 hr at 3 mg/kg. In addition, RS-5773 did not cause excessive hypotension or depression of atrioventricular conduction. These results suggest that RS-5773 has a preferable profile as an antianginal agent.