Interaction between the dominant negative mutant and the wild-type envelope proteins of Friend murine leukemia virus

Interaction between the previously obtained dominant negative mutant, referred to as fcr (T. Matano, T. Odawara, M. Ohshima, H. Yoshikura, and A. Iwamoto, J. Virol. 67:2026-2033, 1993), and the wild-type envelope proteins (Env) of Friend murine leukemia virus was examined. The wild-type Env was bound to the fcr mutant Env and trapped in the endoplasmic reticulum. The virus receptor was not involved in this interaction.

Primary plasmacytoma of the thyroid: a case report and comparative literature study between Western nations and Japan

A 52 year old man presented with primary thyroid plasmacytoma. The patient was initially followed up for thyroid dysfunction. The histological examination of the removed thyroid revealed a proliferation of mature and immature plasma cells indicative of plasmacytoma with Hashimoto's disease. After radiotherapy (40 Gy) to the neck following right hemi-thyroidectomy, the patient is currently alive and well 3 years after diagnosis without any evidence of tumor. The immunohistological examination of the removed thyroid showed monoclonality for immunoglobulin G-Kappa light chains. Sixty-six literature cases of primary thyroid plasmacytoma were reviewed and comparison of the clinical and histological characteristics between Japanese and Western cases noted. The incidence of the patients with antithyroid antibody was significantly lower (P < 0.01) in Western patients (42.9%) than in Japanese patients (87.5%). The higher incidence of thyroid dysfunction and Hashimoto's disease in Japan in comparison with Western nations was well reflected in the incidence of antithyroid antibody.

Progressive activity in latent prostate carcinoma defined by argyrophilic staining of the nucleolar organizer regions (AgNOR)

Argyrophilic staining of the nucleolar organizer regions (AgNOR) was studied in 30 cases of benign prostatic hyperplasias (BPH), 17 cases of latent prostate carcinomas, 50 cases of clinical carcinomas and seven cases of metastatic lesions from prostate carcinomas. The criteria for these comparisons were the number of positive-staining dots per nucleus, the area of the dots, and a relative score determined by multiplying the number of positive-staining dots in the nuclei by the areas of the dots. Overall, there were no significant differences in these three parameters between BPH and latent carcinomas. Among latent carcinomas, however, significantly higher AgNOR scores were observed for infiltrative lesions than for non-infiltrative lesions. AgNOR dot number, area and score increased as tumors became less differentiated, with no significant differences detected in metastatic versus non-metastatic carcinomas. These results suggest that some latent tumors are similar in biological behavior, such as cell proliferation, to clinical carcinoma.

Efficacy of amlodipine besilate therapy for variant angina: evaluation by 24-hour Holter monitoring

The efficacy of amlodipine, a calcium antagonist, was investigated in 12 patients with variant angina. Amlodipine was administered at a dose of 5 mg once daily, and efficacy was assessed from the frequency of anginal attacks, the frequency of ST elevation or depression, and the extent of ST segment changes [ST segment elevation or depression (mm) x duration (seconds)] on the Holter ECG before and after treatment. The frequency of ST elevation during the observation period was 1.67 +/- 0.33 times/day (symptomatic attacks: 1.17 +/- 0.21/day; asymptomatic attacks: 0.50 +/- 0.19/day), and this significantly decreased to zero per day (both symptomatic and asymptomatic attacks) after treatment (p < 0.05). The extent of ST segment elevation during the observation period was 507.5 +/- 156.6 mm.sec/day (symptomatic: 382.5 +/- 102.9 mm.sec/day; asymptomatic: 125.0 +/- 62.0 mm.sec/day), and such changes were completely suppressed (both symptomatic and asymptomatic) by treatment (p < 0.05). The frequency of ST depression was 2.08 +/- 0.42 times/day (symptomatic: 0.25 +/- 0.13/day; asymptomatic: 1.83 +/- 0.37/day) during the observation period, while it was 1.50 +/- 0.36 times/day (symptomatic: 0.25 +/- 0.13/day; asymptomatic: 1.25 +/- 0.30/day) after treatment. Although anginal attacks remained unchanged, asymptomatic attacks tended to decrease (p = 0.07).(ABSTRACT TRUNCATED AT 250 WORDS)

Establishment of estrogen receptor-positive transplantable rat thyroid tumor cell lines in vivo

We established 17 transplantable rat thyroid tumor cell lines from the primary thyroid tumor of rats induced by N-bis(2-hydroxypropyl)nitrosamine. Among the 17 tumor cell lines established, only two of them (D1 and G1) were estrogen receptor (ER) positive. These two cell lines were characterized with respect to transplantability, histological features, ER contents and cellular localization, and expression of ER message. The ER contents, determined by dextran-coated charcoal assay, were 13.3 and 20.7 fmol/mg protein for D1 and G1 cell lines, respectively. Scatchard plot analysis indicates that the dissociation constants (Kd) were 0.17 and 0.4 nM, respectively, for D1 and G1 cell lines. Sucrose density centrifugation analysis detected a hormone-receptor complex which sedimented at the 4S region, characteristic for ER. Immunohistological staining revealed that the ER was localized in the nuclei. The presence of ER in D1 and G1 cell lines was further confirmed by reverse transcriptase-polymerase chain reaction to detect the ER mRNA. These results demonstrated that ER is expressed in some thyroid tumors. The ER-positive transplantable tumor cell lines are useful for studying the direct effect of estrogen on thyroid tumors in vitro and in vivo.

Sequence-specific binding of protein factors to two independent promoter regions of the acidic tobacco pathogenesis-related-1 protein gene (PR-1)

Gel shift mobility analysis, using the proximal 0.3 kb fragment of the tobacco pathogenesis-related protein 1a gene (PR-1a) and nuclear extracts from healthy Samsun NN tobacco leaves, which do not produce PR-1 proteins, showed a broad shifted signal with low mobility. This signal was not detected with nuclear proteins from the interspecific hybrid of Nicotiana glutinosa x Nicotiana debneyi, which constitutively produces the PR-1a protein. Similar shifted signals were detected with both proximal and distal regions of the 0.3 kb fragment using nuclear proteins from healthy Samsun NN tobacco, but not with proteins from the interspecific hybrid. Further experiments, performed using 5' or 3' truncated fragments of the 0.3 kb fragment, identified two independent binding sites: a distal site between -179 and -168 bp from the transcription start site, and a proximal site between -61 and -37 bp. Footprint analysis revealed two protected sequences, a distal region between -184 and -172 bp, and a proximal region between -68 and -51 bp. These results indicate the presence of regulatory factor(s) for expression of the acidic PR-1a gene. The possibility of negative regulation of the gene is discussed.

Immunohistochemical evaluation of estrogen receptor status in benign prostatic hypertrophy and in prostate carcinoma and the relationship to efficacy of endocrine therapy

The levels of estrogen receptors in human benign prostatic hypertrophy and in various pathological classifications of prostate carcinoma were assessed using immunohistochemical methods. All cases of benign hypertrophy showed elevated levels of estrogen receptor, while receptor-positive cells were detected in only 48% of carcinomas, indicating a negative correlation between receptor status and malignancy. Furthermore, the prognosis for effective endocrine therapy was poor in cases where tissues demonstrated low or negative receptor levels. In addition, the estrogen receptor status was compared to cell kinetic index such as proliferating cell nuclear antigen and argyrophilic staining of the nuclear organizer region.

[A case of dual origin of the left anterior descending coronary artery from the left and right coronary arteries with variant angina]

We present a case of a 68-year-old male inflicted with a rare anomaly of the coronary artery. He had been suspected to have worsening effort angina and underwent urgent cardiac catheterization. The coronary angiography revealed 75% stenosis in the first diagonal branch. The left anterior descending artery was terminated in the mid portion and did not reach the apex. Instead, an anomalous coronary artery from the portion just proximal to the right coronary artery reached the apex. After cardiac catheterization, nocturnal chest pain at rest started to occur frequently. We suspected that vasospasm may have occurred because ST segment elevations in leads II, III, aVF were recorded on the electrocardiogram. Administration of diltiazem (120 mg per day) suppressed angina. Exercise stress electrocardiogram and thallium-201 myocardial scintigram did not show apparent ischemia. This case suggests that we must consider the presence of coronary vasospasm even in patients with clinically-supposed effort angina, to be possibly due to vasospasm occurring in anomalous coronary arteries.

Collagenase and collagenase inhibitors secreted by cultured human periodontal ligament cells

We have developed a new assay method for collagenase activity, in the presence of two different types of collagenase inhibitors, in culture medium of periodontal ligament (PDL) cells. Human PDL cells were cultured with serum-free alpha-MEM for 5 days after reaching confluency, and the culture medium was then harvested. Collagenase and collagenase inhibitors in the medium were concentrated by ammonium sulfate precipitation. The precipitate was dissolved, and the suspension was applied to an Ultrogel AcA 54 column for partial purification. Collagenase inhibitor activity was detected as two peaks; a small inhibitor molecule of about 32 kDa sensitive only to dithiothreitol (DTT), and a large one of about 70 kDa considerably more sensitive to 4-aminophenylmercuric acetate (APMA) than to DTT. Therefore, pretreatment of the sample preparation with both DTT and APMA was necessary in order to inactivate the inhibitors prior to assay of latent collagenase. This observation indicates that PDL cells secrete collagenase and two collagenase inhibitors without any stimulation in vitro.

Active oxygen-induced modification alters properties of collagen as a substratum for fibroblasts

Acid-soluble collagen from rat skin was modified by active oxygen in vitro, and properties of the modified collagen as a substratum for fibroblasts were studied. When collagen was treated with ascorbate-copper ion systems, cross-linking and a little degradation occurred rapidly. The cells attached but spread poorly on the modified collagen gel as compared with on the untreated collagen gel. On the other hand, when collagen was treated with H2O2-copper ion systems, only degradation of collagen molecule occurred rapidly. This treatment did not affect the attachment and spreading of the cells on the collagen gel, but when the incubation was continued for a long time, the cells migrated actively and gathered. Thymidine incorporation by the cells was suppressed on both modified collagen gels as compared with that on untreated collagen gel, and the extent of the suppression on the H2O2-copper-treated collagen was larger than that on the ascorbate-copper-treated collagen. These results indicate that the active oxygen-induced cross-linking and degradation significantly alter properties of collagen as a substratum for fibroblasts.

trans-dominant interference with virus infection at two different stages by a mutant envelope protein of Friend murine leukemia virus

A dominant negative mutant Friend murine leukemia virus (FMLV) env gene was cloned from an immunoselected Friend erythroleukemia cell. The mutant env had a point mutation which resulted in a Cys-to-Arg substitution at the 361st amino acid in the FMLV envelope protein (Env). The mutant Env was retained in the endoplasmic reticulum (ER) and accumulated because of its slow degradation. The NIH 3T3 cells expressing the mutant env were resistant to ecotropic Moloney MLV (MoMLV) penetration, suggesting that the mutant Env traps the ecotropic MLV receptors in the ER. When the mutant env gene was transfected into and expressed in the cells persistently infected with MoMLV, the wild-type Env was trapped in the ER, and the MoMLV production was suppressed. Thus, the mutant Env accumulating in the ER trans-dominantly and efficiently interfered with the ecotropic MLV infection at both the early and the late stages.

Immunohistochemical analysis of estrogen receptors in 313 paraffin section cases of human thyroid tissue

Three hundred and thirteen cases of human thyroid tissues, comprising 39 nodular goiters from 34 females and 5 males, 130 adenomas from 93 females and 37 males, and 144 carcinomas from 99 females and 45 males were used for the present immunohistochemical assessment of estrogen receptor (ER) expression. Thirty-three cases of follicular carcinoma, 115 cases of papillary carcinoma and 6 cases of anaplastic carcinoma were included in the malignant tumor group. Incidences of ER-positive cases were 23/39 (58.9%) for nodular goiter, 44/130 (33.8%) for adenoma and 26/144 (18.0%) for cancer. In the individual carcinoma categories, 7/23 (30.4%) follicular, 19/115 (16.5%) papillary and 0/6 (0%) anaplastic lesions were judged as positive cases. Thus, the incidence of ER-positive cases tended to decrease with the degree of malignancy; this trend being similar in both sexes. Moreover, the average ages of ER-positive cases were lower than those of ER-negative cases for all types of thyroid carcinoma except the follicular variety in males. It was thus suggested that ER expression may be related to prognosis and tumor growth at early stage. Since the incidence of ER does not significantly differ between females and males, the observed sex differences regarding thyroid tumor incidence may reflect the higher estrogen serum content in females.

Electrophysiologic study and ergonovine provocation of coronary spasm in unexplained syncope

A total of 38 patients with syncope in whom a cause was not assigned or suggested by the initial history, physical examination and electrocardiography (ECG) were studied. Twenty-four patients underwent cardiac examination with Holter ECG, electrophysiologic testing with programmed ventricular stimulation (EPS) and/or coronary arteriography including ergonovine provocation (ergonovine CAG). The study with Holter ECG, EPS and ergonovine CAG yielded a presumptive diagnosis in 36 patients (36/38 = 95%), 11 with vasopastic angina, 7 with ventricular tachycardia, 4 with ischemic heart disease, 9 with sick sinus syndrome (SSS), 1 with drug induced SSS, 3 with A-V block, 1 with supraventricular tachycardia, 1 with hypertrophic cardiomyopathy, 1 with aortic valve stenosis and 1 with carotid sinus syndrome (included are 1 patient with ventricular tachycardia+ischemic heart disease, 1 with SSS+vasopastic angina and 1 with ventricular tachycardia+vasospastic angina). Therapy based on these findings provided complete symptomatic relief in all patients during a mean follow up of 25 +/- 10 months (range 5-45 months). In conclusion, EPS and ergonovine CAG are useful in the diagnosis and therapy of unexplained syncope.

Gingival epithelial cells secrete a substance which increases the collagenolytic enzyme activity of periodontal ligament cells

To examine whether the gingival epithelium provokes a loss of connective tissue attachment during periodontitis, periodontal ligament (PDL) cells and gingival fibroblasts (GF) were cultured with conditioned medium of gingival epithelial cells, and the collagenolytic activity of PDL cells and GF were examined, respectively. The epithelial cells were cultured in the presence or absence of lipopolysaccharide (LPS), and the respective conditioned media were added to the cultures of PDL cells and GF. The collagenolytic response of PDL cells to both of the conditioned media was 3- to 10-fold higher than that of each control, whereas the response of GF was only 1.4-fold higher. The LPS-stimulated epithelial conditioned medium showed a stimulation rate for collagenolytic activity similar to that of the LPS-free conditioned medium. These results suggest that human gingival epithelial cells, without LPS stimulation, secrete a substance which accelerates the collagenolytic enzyme activity of PDL cells for degradation of PDL fibers, in the absence of GF enzyme activity.

New HIV plaque titration; application to the assay of neutralizing antibody

A simple, sensitive and accurate plaque assay was developed using HPB-Ma, a variant of the human T-cell line HPB-ALL, which becomes adherent to the substratum after infection with an amphotropic murine sarcoma virus (MSVa). The simplicity of this novel plaque assay allowed us to examine a large number of serum samples from patients with HIV infection for neutralizing antibody activity against two human immunodeficiency virus type-1 (HIV-1) strains. During the progression of clinical disease, the neutralizing activity in the sera from two individual patients remained unchanged or increased. A patient with a known time of HIV infection produced cross-neutralizing antibody at 25-34 weeks. The neutralizing activity in the sera from 17 asymptomatic carriers, four patients with AIDS-related complex and four AIDS patients was also examined and was found to be unrelated to the clinical stage.

Chemical carcinogenesis in the thyroid gland

Chemical carcinogens and promoters in thyroid carcinogenesis may be divided into two types, one having goitrogenic effects, the other not having these effects e.g. phenobarbital, 4,4'-diaminodiphenylmethane. The influence of sex hormones like estrogen and testosterone remains unclear, although some thyroid tumors have estrogen receptors. Further studies in this area are necessary.

Balloon catheter with check valves for experimental relief of acute aortic regurgitation

To evaluate the ability of a newly designed balloon catheter with check valves to temporarily relieve hemodynamic deterioration in acute aortic regurgitation, we produced an experimental model of acute aortic regurgitation in closed-chest dogs using endomyocardial biopsy forceps. Aortic regurgitation was produced until an increase in aortic pulse pressure of over 50% was achieved. Left ventricular end-diastolic pressure rapidly increased after the production of aortic regurgitation. Immediately after the catheter began functioning, pulse pressure decreased from 133 +/- 1 to 78 +/- 5 mm Hg (mean +/- SEM) and left ventricular end-diastolic pressure also decreased from 26 +/- 1 to 13 +/- 1 mm Hg. These effects lasted as long as the catheter functioned. Although a mild (21 +/- 8 mm Hg) pressure gradient between the left ventricular peak systolic pressure and the aortic peak systolic pressure was observed when this catheter was used, forward stroke volume was no less than in the group in which the catheter had not been used. These findings suggest that the balloon catheter with check valves may effectively reduce aortic regurgitation.

A case of vasovagal syncope with convulsions--the effects of midodrine hydrochloride

A 42-year-old female had suffered from repeated syncope. She had vasovagal syncope with convulsions from vasodilatation and cardiac standstill which lasted for 9.8 sec. The 60 degrees head-up tilt test, nitroglycerin injection and isoproterenol infusion provoked vasovagal reaction. Although a beta blocker was not effective in preventing tilt-induced hypotension and bradycardia, midodrine hydrochloride (alpha-1 stimulant) or atropine prevented it. In this patient, insufficient constriction of capacitance vessels might have played an important role in activation of an inhibitory reflex from cardiopulmonary mechanoreceptors which caused hypotension and bradycardia.