Accumulation of specific amino acid substitutions in HLA-B35-restricted human immunodeficiency virus type 1 cytotoxic T lymphocyte epitopes.

HLA is one of the genetic factors that influence the clinical course of HIV-1 infection, and patients with HLA-B35 are prone to rapid disease progression. Nine viral epitopes that are recognized by cytotoxic T lymphocytes (CTLs) in an HLA-B35-restricted manner were determined. To examine how HIV-1 sequences are selected by CTLs in vivo, we sequenced the nine CTL epitopes of the virus in patient plasma. Here we show that certain amino acid substitutions at three epitopes were observed with significantly higher frequency in HLA-B35-positive patients than in HLA-B35-negative patients. By performing experiments with CTL clones established from the HLA-B35-positive patients, it was determined that one of the three substitutions was probably an escape mutation. However, concerning the other two epitopes, representative CTL clones killed target cells pulsed with mutant peptides as efficiently as those pulsed with wild-type peptides, suggesting that CTLs that can be established in vitro are not functioning properly in vivo. Amino acid sequence drift in all HLA-B35-restricted epitopes was rare during the observation period (1 year). Our results may have relevance in understanding the rapid clinical progression in HLA-B35-positive patients.     

A Study of Malignant Bile Duct Stenosis Using Percutaneous Transhepatic Cholangioscopy

Abstract: From June, 1987 to November, 1989, 11 patients with malignant bile duct stenosis, which was later confirmed by surgery or autopsy, were examined by percutaneous transhepatic cholangioscopy (PTCS) and by an endoscopic biopsy. The endoscopic findings obtained with the usual observation methods and methylene blue staining and the histological findings of the biopsy specimens were compared. A fine vascular proliferation was seen in all of the patients and a granular appearance was noted in patients with carcinoma of the major papilla. The papillary appearance was noted in one case each of pancreatic carcinoma, bile duct carcinoma and carcinoma of the major papilla. Marginal protrusion was not noted in patients with pancreatic carcinoma. A distorted narrow segment was seen only in cases of pancreatic carcinoma. The presence of a granular appearance indicated that the carcinoma was exposed on the surface. A high degree of fine vascular proliferation and a papillary appearance tended to indicate a carcinoma which invaded mainly into the fibromuscular layer without invasion of the mucosa. The methylene blue staining method was simple and effective for better visualization of the surface structure of the abnormal area, normal mucosa and the border zone.     

Purification and properties of neuraminidase from the culture medium of Bacteroides loescheii

Neuraminidase was purified from the culture medium of Bacteroides loescheii ATCC 15930 by ultrafiltration followed by a DEAE-Sephacel anion exchange chromatography, fast-protein liquid chromatography using Mono P column and high-performance liquid chromatography using a Shim-pack Diol-300 column. The molecular weight of the purified enzyme was measured to be approximately 87 kDa and the optimal pH was at 4.8. Although the enzyme was able to hydrolyze the substrates with alpha,2-3, alpha,2-6, and alpha,2-8 linkages of N-acetylneuraminic acid, the rate of hydrolysis of N-acetylneuraminosyl-alpha,2-3-lactose was greater than that of the alpha,2-6-isomer.     

Rapid Induction of Endometrial Carcinoma in ICR Mice Treated with N-Methyl-N-nitrosourea and 17β-Estradiol

The present study was undertaken to develop an animal model for endometrial neoplasms. A total of 107 female ICR mice, 10 weeks of age, were used and treated as follows: Group 1 (31 mice) was given intravaginal instillation of N-methyl-N-nitrosourea (MNU) solution (1 mg/100 g body wt.) once a week for three weeks and then fed diet containing 5 ppm 17/β-estradiol (E₂) for 20 weeks, starting one week after the last exposure to MNU, Group 2 (30 mice) was given MNU alone. Group 3 (31 mice) was given E₂ diet alone. Group 4 (15 mice) was fed the basal diet alone and served as the untreated control. At the termination of the experiment (week 23), all surviving mice were killed. Histopathological examination revealed that adenocarcinomas in the uterine corpus developed in mice of Groups 1-3, with a high incidence of endometrial hyperplasia. The incidence of endometrial carcinomas in Group 1 (15/31, 48%) was significantly higher than in Group 2 (2/29, 7%, P < 0.001) or Group 3 (7/31, 23%, P > 0.01). In the uterine cervix, small numbers of squamous cell carcinomas and pre-neoplastic lesions (dysplasias and hyperplasias) were also present in mice of Groups 13. In Groups 1 and 3, an increased E₂/progesterone (P) ratio was observed. Thus, the results indicated that this medium-term model for endometrial neoplasms is useful for studying the pathogenesis of endometrial cancer and that an increased E₂/P ratio is an important factor for the development of endometrial adenocarcinoma.     

A New Experimental Model for Drug Studies: Effects of Phenobarbital and Phenytoin on Photosensitivity in the Lateral Geniculate-Kindled Cat

Photosensitivity was acquired as a result of kindling in the lateral geniculate body (GL), and the GL-kindled cat pretreated with DL-allylglycine showed a stable level of photosensitivity. To test the usefulness as a model for the evaluation of anticonvulsant drugs, the effects of phenobarbital (PB) and phenytoin (PHT) on photosensitivity were studied in the GL-kindled cat under DL-allylglycine. PB (5 and 10 mg/kg intravenously, i.v.) completely suppressed photically induced seizures in most subjects at plasma concentrations of 7-16 micrograms/ml, and this anticonvulsant action persisted for at least 4 h after the injection. PHT (15 mg/kg, i.v.) at plasma concentrations of 9-15 micrograms/ml produced toxic signs, e.g., pupil dilatation, hypersalivation, and tachypnea. At this dose, PHT was inactive against photically induced myoclonus but prevented the elicitation of a generalized tonic-clonic convulsion. From these results showing that the effects of anticonvulsant drugs on photically induced seizures can be assessed in relation to plasma concentration and acute neurologic toxicity, we suggest that the GL-kindled cat is a potentially useful animal model of epilepsy for testing the efficacy of anticonvulsant drugs.     

Gastric resection in the aged (≥ 80 years) with gastric carcinoma: a multivariate analysis of prognostic factors

Background : The incidence of gastric neoplasm is increasing in the elderly population. Therefore, a rational method of treatment for gastric cancer in the elderly should be constituted to improve the survival. The purpose of the present study was to clarify whether the patient’s age is an independent prognostic factor and to determine clinicopathological characteristics in the elderly. Methods : Curative resection of gastric cancer was carried out on 601 patients who were 40 years or older. They were divided into the following two groups: younger patients (between 40 and 79 years old) and elderly patients (80 years or older). The clinicopathologic features of these patients were reviewed retrospectively and multivariate analysis was carried out. Results : The distinguishing features of gastric cancer in the elderly patients were intestinal and mixed types of cancer, distal third stomach dominancy in the tumour location, advanced stage of disease, and a low rate of extensive lymph node dissection (D3 or more). Regarding the recurrence site, the liver was the dominant site in the elderly group (25.3% in the younger group vs 54.5% in the elderly group). The 10‐year disease‐free survival rate of the elderly group was 53.2%, which was significantly worse than that (79.9%) of the younger patients (P = 0.0004). In multivariate analysis, an age of ≥ 80 years is an independent prognostic factor, as well as stage, depth of tumour invasion, lymph node metastasis, scirrhous carcinoma, and blood transfusion. Conclusions : Results indicate that gastric cancer in elderly patients has a poorer prognosis than that in younger patients.     

Asymptomatic cerebral infarction on brain MR images and cognitive function in elderly diabetic patients

Background: The assessment of cognitive function is of great importance in the management of elderly patients with diabetes mellitus. The purpose of the present study was to examine the effects of glucose control and asymptomatic cerebral infarction on impaired cognitive function in elderly patients with diabetes mellitus. Methods: Two hundred and thirteen elderly diabetic patients (59 men, 154 women) with a mean age of 75 years; and 40 non‐diabetic subjects participated in this study and underwent both brain magnetic resonance imaging (MRI) and several domains of cognitive function tests. Based on the brain MRI findings and neurological deficits, the subjects were divided into four groups: (i) the symptomatic cerebral infarction (CI) group; (ii) the asymptomatic CI group; (iii) the diabetic control group without any CI; and (iv) the non‐diabetic control group. Cognitive function was assessed using the mini‐mental state examination (MMSE), and the subtests of Wechsler Adult Intelligence Scale – Revised (WAIS‐R) (the digit symbol test, the backward digit span test, the similarities test, and the picture arrangement test). Attention/complex psychomotor skill and visual memory were assessed with the digit symbol substitution test, the Stroop test, and the Benton visual retention test. Results: Attention/complex psychomotor skill and visual memory were more impaired in the diabetic control group without any CI than in the non‐diabetic control group. The asymptomatic and symptomatic CI groups were significantly inferior to the non‐diabetic and diabetic controls in the digit symbol substitution test and Stroop test. The degree of cognitive impairment significantly correlated to the presence and number of small‐sized cerebral infarction, but to a less degree, large‐sized infarction. Multivariate analysis revealed that age, HbA1c, and cerebral infarction on MR images were independently associated with the impairment of complex psychomotor skill in patients with diabetes mellitus. Conclusions: The presence of asymptomatic cerebral infarction on brain MR images as well as hyperglycemia could explain the impairment of attention/complex psychomotor skill and visual memory in elderly patients with diabetes mellitus.