Immune abnormality in relation to nonimmune diseases in SAM mice

A series of related strains of senescence-accelerated mouse (SAM) shows strain-unique age-related diseases, such as amyloidosis, deficit in learning and memory, osteoporosis, and brain atrophy, while many of these disease-prone mouse (SAMP) strains have impaired immune activity as young adults, and have a short life span, probably not due directly to the diseases. Because the mean life span was prolonged and the time of the disease onset was delayed by a low-calorie dietary condition or a specific pathogen-free environment, both of which ameliorate the impaired immune activity, the enhancement of immune activity may help decrease the deteriorative process of aging, to that seen in ordinary strains of mice. Studies using the SAMP model may help elucidate the role of immunity in the aging process. Herein, we review the cellular and genetic basis of the immune abnormality in SAMP mice, then discuss the relationship between immune abnormality and development of the age-related disease, senile amyloidosis, findings obtained on SAMP hybrid mice and congenic mice for disease-related genes. Activation of the gene(s) for senile amyloid per se shortened the life span, and the early development of the immune dysfunction primarily seems to be both genetically and physiologically independent of amyloidosis, although the disease may be indirectly modified in the aged with depressed immune activity.

[Surgical treatment for patient ductus arteriosus in an aged patient]

A successful closure of patent ductus arteriosus (PDA) in a 70-year-old women is described. The patient had poor pulmonary function and calcification of the aortic arch and the descending aorta, as well as arteriosclerosis obliterans bilaterally in the iliac arteries. We therefore performed trans-pulmonary artery direct closure of the ductus arteriosus via a median strenotomy. In surgery, we used a Foley balloon catheter inserted into the aorta through the ductus to prevent backflow. Leakage of blood from the ductus, even with use of balloon occlusion, required the reduction of perfusion flow to 500 ml/min and temporary circulatory arrest. Rectal temperature was 27 degrees C when the aorta was cross-clamped. The ductus orifice was primarily closed with three mattress sutures with pledgets, and this sutured orifice was secondarily covered with a bovine pericardial patch. The postoperative course was satisfactory. Trans-pulmonary artery direct closure of the PDA using cardiopulmonary bypass is useful for aged patients. This patient is, as far as our knowledge, the oldest surgical report in Japan.

Forskolin derivatives. I. Synthesis, and cardiovascular and adenylate cyclase-stimulating activities of water-soluble forskolins

Water-soluble forskolin and 7-deacetylforskolin derivatives with an aminoacetyl, a 3-aminopropionyl, or a 4-aminobutyryl group at the 6- or 7-position were prepared, and their positive inotropic as well as vasodilative activities were evaluated in anesthetized dogs. 7-Deacetylforskolin (2) and 7-deacetyl-1-silylforskolin (6) were converted to the corresponding 7-chloroacylderivatives (3, 7, 10), which were reacted with amines to obtain 7-aminoacyl-7-deacetylforskolins (4a-f, 9a, b, 11). The 7-acyl substituents migrated to the 6-position with sodium hydroxide in acetonitrile-water to afford 6-aminoacyl-7-deacetylforskolins (12a-f). The 7-position of 12a, d-f was selectively acetylated with acetyl chloride to obtain the corresponding 6-aminoacylforskolins (13a-d). Among the 6-aminoacylforskolins, 6-(3-dimethylaminopropionyl)forskolin (13b) and 6-(4-dimethylaminobutyryl)forskolin (13d) exhibited potent positive inotropic and vasodilative activities comparable to those of forskolin (1). The activities of 13b and 13d were approximately ten times more potent than those of 7-aminoacyl- and 6-aminoacyl-7-deacetylforskolins (4a-f, 9a, 12a-c, f). 6-Dimethylaminoacetylforskolin (13a) and 6-(3-diethylaminopropionyl)forskolin (13c) were less potent than 1. The effects of the soluble forskolins on adenylate cyclase activity were also examined in vitro. 6-Aminoacylforskolins (13a-d) exhibited potent adenylate cyclase-stimulating activity, comparable to that of 1.

Localization of small-cell lung cancer xenografts with iodine-125-, indium-111-, and rhenium-188-somatostatin analogs

We examined the potential of radiolabeled somatostatin analogs, 125I-Tyr-3-octreotide (125I-octreotide), (111)In-DTPA(diethylenetriaminepentaacetatic acid)-D-Phe-1-octreotide (111In-octreotide), and 188Re-octreotide for targeting small-cell lung cancer (SCLC) in a mouse model. Tyr-3-octreotide was labeled with 125I by the chloramine T method, and (111)In-octreotide was obtained as a kit, while 188Re was eluted from a 188W/188Re generator, and octreotide was directly labeled with 188Re by reducing disulfide bonds. The 125I-, 111In-, and 188Re-octreotides were injected i.v. into athymic mice bearing NCI-H69 tumors, and the biodistributions were determined at 15 min, and 2, 4, 8, and 24 h. Tumor uptakes were 0.5+/-0.2, 0.3+/-0.1, 0.3+/-0.1 %ID/g, and tumor-to-blood ratios were 1.8, 11.9, 1.2 at 8 h for 125I-, 111In-, and 188Re-octreotides, respectively. Accumulations of 111In-octreotide in normal tissues were lower than those of 125I- and 188Re-octreotides. 188Re-octreotide can be used to localize SCLC lesions as efficiently as radioiodinated octreotide. However, 111In-octreotide was the most suitable agent to obtain high tumor-to-normal tissue contrast for localizing SCLC.

[Effectiveness of NKH477, a novel forskolin derivative, in rat cardiac preparations with desensitized beta-adrenoceptors]

Effects of prolonged noradrenaline infusion on the density of cardiac beta-adrenoceptors, phosphodiesterase (PDE) and adenylate cyclase (AC) activities, and the ability of NKH477, 6-(3-dimethylaminopropionyl) forskolin hydrochloride, to increase tension development and heart rate were studied in rat cardiac preparations. Noradrenaline infusion (400 micrograms/kg/hr, s.c.) for 7 days significantly decreased cardiac beta-adrenoceptor density (Bmax), whereas the binding affinity (Kd) of the ligand was unchanged. The basal cardiac PDE activity was increased in treated rats, whereas there was no difference in the basal cardiac AC activity between treated and untreated rats. Significant decreases in basal developed tension and heart rate were observed in the left and right atrial muscles from treated rats, respectively. The positive inotropic and chronotropic potencies of NKH477 were unaffected by noradrenaline infusion, whereas the positive inotropic potencies of isoproterenol and 3-isobutyl-1-methylxanthine were significantly reduced. Thus, NKH477 appears to be superior to beta-adrenoceptor agnosits or PDE inhibitors as a cardiotonic drug in the treatment of heart failure accompanied by beta-adrenoceptor downregulation.

Termination by early deletion of V beta 8 + T cells of aged mice in response to staphylococcal enterotoxin B

The changes in the T cell repertoire of aging BALB/c mice include an increase of V beta 8 + T cells, most of which have a relatively low density of T cell receptors (TCR). We investigated the response of V beta 8 + T cells to staphylococcal enterotoxin B (SEB), a superantigen from a common bacterium, the anamnestic response to which is thought usually to be part of the defense against infection. The injection of an amount of SEB optimum for V beta 8 + T cell proliferation in young mice induced little or no proliferative response in aged mice, and within one or two days they died in shock with apoptotic cells in the spleen, a sign of T cell-shock caused by SEB. Flowcytometry analysis (FCA) 15 h after SEB injection, when cell division had not yet started, revealed the loss of 90% of V beta 8 + T cells in the blood and of 50% in the spleen in mice of all ages tested. However, conspicuous in the remaining V beta 8 + T cells in the spleens of the young mice but not in those of the aged mice, was an increased cellular complexity, as shown by the fact that light was strongly side scattered in FCA, indicating intracellular re-organization. The remaining T cells in the young could include progenitors for the expanding population of V beta 8 + T cells. As seen in lethal shock, V beta 8 + T cells in the aged are not unresponsive to SEB in vitro. They responded to the antigen by increasing the amount of TCR up to the level of that in young mice, but without proliferation. The proliferation arrest of V beta 8 + T cells of aged mice was found to be an intrinsic defect in in vitro cell mixture experiments, in which they were cocultured with young spleen cells which provided a complete immune microenvironment. It was simultaneously found in vitro that most of the V beta 8 + T cells from aged mice disappeared after antigen stimulation and that their disappearance was prevented by the presence of spleen cells from young mice, although they still did not proliferate. Taken all together the findings suggest that V beta 8+ T cells in the aged are at the end state of maturation and terminate by apoptotic death, causing T-cell shock in response to SEB.

Effect of circulating antigen on immunoscintigraphy of ovarian cancer patients using anti-CA125 monoclonal antibody

The murine monoclonal antibody (mAb) 145-9 recognizes an epitope present on CA125 but different from the epitope defined by the mAb OC125. To evaluate the clinical usefulness of the 145-9 antibody, immunoscintigraphy was performed in ovarian cancer patients and the effect of circulating CA125 on tumor imaging was investigated. Two milligrams (74 MBq) of 111In-labeled 145-9 was injected intravenously into 11 patients with ovarian cancer. Pre-injection serum CA125 concentrations were between 166 U/ml and 7414 U/ml. Tumors were visualized in 10 of 11 patients. In two patients, lymph nodes that were not detected by other imaging modalities but were clinically suspected as metastases were visualized. There was no correlation between serum CA125 level and antibody uptake in the tumors. Immune complexes between the antibody and circulating antigen were observed in sera of all the patients, but the fraction of radioactivity in complex form did not correlate well with serum CA125 levels. The immune complexes survived in the circulation and the circulating radiolabel, including immune complexes, was still bound to solid-phase CA125. The plasma clearance rate and hepatic uptake of the antibody were not significantly affected by circulating CA125. In conclusion, the antibody 145-9 formed complexes with CA125 in vivo but this did not Compromise the outcome of antibody imaging. The antibody 145-9 can be used in immunoscintigraphy of ovarian cancer irrespective of serum CA125 level.

[Measurement of serum catalase activity and its clinical significance]

Catalase (CAT) is an enzyme to scavenge H2O2 and to protect peroxidation of cell wall lipid and lipoproteins. The increase in its activity has been observed in several diseases as an compensating reaction. The decrease in its activity may be related to some pathophysiologies of diseases. However, there has been few reports on the measurement of serum CAT activity. We formerly reported the method to measure CAT accurately with an automated analyzer. In the present experiment, we measured CAT in various kinds of diseases and healthy controls by this method. By an analysis of serum samples which were obtained from randomly selected 1,051 patients at Chibune Hospital for 12 months (from January to December, 1993), we obtained following results. The CAT of neuromuscular, cardiovascular and metabolic diseases were significantly high (p < 0.01). The CAT of psychiatric and otorhinopharyngologic diseases were significantly low (p < 0.01). There was significant relationship between CAT and some biochemical markers. CAT is thought as a protector against tissue injuries or circulatory insufficiencies. These results indicate that CAT increases in some kinds of diseases as a protection reaction to the injury, and that the decrease of CAT may cause some kinds of diseases.

Periosteal ganglion of the tibia

Radiographic, computed tomographic and scintigraphic findings of a patient with separated, multilocular periosteal ganglion are reported. Multiple periosteal cystic masses with calcification in small parts of the cyst walls were demonstrated in the surface of the left tibia by plain radiograms and CT. The accumulations of technetium-99m hydroxymethylene diphosphonate and pentavalent technetium-99m dimercaptosuccinic acid were shown in the calcification in the periosteum and wall of the cyst. Needle puncture revealed that the masses were filled with jelly-like fluid. The masses were diagnosed as multiple ganglionic cysts at the periosteum of the left tibia.

The pharmacodynamics of 6-(3-dimethylaminopropionyl)forskolin and a possible metabolite in beagles

A specific gas chromatography/mass spectroscopy method with a detection limit of 0.1 ng/mL was developed for the measurement of 6-(3-dimethylaminopropionyl)forskolin (1) in beagle plasma. Using this method, plasma concentrations of 1 in beagles given pharmacologically effective intravenous doses of 1.HCl were determined. The observed maximal plasma concentrations rapidly decreased with time, and half-lives of the alpha-phases were < 9 min. Pharmacological effects of 1 on the cardiovascular parameters were simultaneously evaluated in one of the studies. Decreases of the pharmacological effects were slower than decreases in plasma concentration of 1. In addition, 6-(3-methylaminopropionyl)forskolin (N-monodemethyl 1), an expected initial metabolite of 1, was prepared and found to be as pharmacologically active as 1 in beagles. These results and others strongly suggest that a metabolite(s) of 1 contributes to the pharmacological effects of 1 in beagles.

[Effect of cilnidipine on renal function in SHR and endothelin-induced renal dysfunction]

Effect of cilnidipine (CIL) on renal function in SHR were evaluated in comparison with that of nifedipine (NIF) and nicardipine (NIC). In conscious SHR, CIL (3 and 10 mg/kg, p.o.) increased the urine volume, urinary Na+ excretion and urinary Na+/K+ ratio. NIF (3 and 10 mg/kg, p.o.) and NIC (10 mg/kg, p.o.) also increased the urine volume and urinary Na+ excretion, but not the urinary Na+/K+ ratio. In anesthetized SHR, CIL (3 and 10 micrograms/kg, i.v.) and NIF (10 micrograms/kg, i.v.) elevated the renal blood flow (RBF), but NIC did not. CIL (10 micrograms/kg, i.v.) also increased the glomerular filtration rate (GFR), whereas NIF did not. Furthermore, we investigated the effect of these three drugs on endothelin (ET)-induced renal dysfunction in anesthetized SHR. ET (2 micrograms/kg, i.v. +30 ng/kg/min) prolongly reduced RBF, GFR and urine volume by 47, 60 and 48%, respectively. CIL (1-10 micrograms/kg, i.v.) improved the decrease in RBF and urine volume induced by ET as well as NIF and NIC. When blood pressure was lowered to the similar extent among the three drugs in ET-treated SHR, CIL increased the RBF and urine volume compared with the others. NIF and NIC did not affect the reduction in GFR by ET, but CIL (0.3-3 micrograms/kg, i.v.) significantly increased GFR. These results suggest that CIL, NIF and NIC all have natriuretic action and no suppressive action on renal function in SHR. In addition, CIL has an ameliorative effect on renal dysfunction in ET-treated SHR, suggesting that CIL might improve renal dysfunction not only in hypertensive patients but also in those with acute renal failure.

Inhibitory effect of cilnidipine on pressor response to acute cold stress in spontaneously hypertensive rats

We investigated the effect of cilnidipine on cardiovascular and neuroendocrine responses to acute cold stress in conscious and unrestrained or moderately restrained spontaneously hypertensive rats (SHRs). Acute cold stress significantly increased mean blood pressure without marked change in heart rate. The acute cold stress-induced elevation in blood pressure was almost abolished by 1 mg/kg, p.o. of prazosin. The cold stress also elevated plasma norepinephrine and epinephrine levels. Cilnidipine at 3 mg/kg, p.o. significantly inhibited the pressor response to acute cold stress. Although 3 mg/kg, p.o. of nifedipine, nicardipine or manidipine lowered mean blood pressure to a similar extent as cilnidipine, none of these three drugs affected the pressor response. Cilnidipine also reduced the cold stress-induced increment in plasma norepinephrine but not the epinephrine level. These findings suggest that acute cold stress may induce the elevation in blood pressure due to an enhanced activation of the sympathoadrenal system in SHRs and that cilnidipine may suppress the pressor response by inhibiting the sympathetic nerve activity.

Inhibitory effect of cilnidipine on vascular sympathetic neurotransmission and subsequent vasoconstriction in spontaneously hypertensive rats

We reported previously that cilnidipine inhibited increases in blood pressure and plasma norepinephrine (NE) level in response to cold stress in spontaneously hypertensive rats (SHRs). In the present study, we investigated the effect of cilnidipine on sympathetic neurotransmission and subsequent vasoconstriction in SHRs. In pithed SHRs, electrical sympathetic nerve stimulation (ESNS) elevated blood pressure, and this pressor response was abolished by guanethidine. Cilnidipine at 10 micrograms/kg, i.v. and phentolamine at 1 mg/kg, i.v. suppressed the pressor response to ESNS by 28 +/- 6% and 67 +/- 3%, respectively. Neither nifedipine nor nicardipine inhibited it. The pressor response to exogenous NE was not influenced by cilnidipine. alpha, beta-Methylene ATP inhibited the pressor response to ESNS in the presence or absence of phentolamine. Cilnidipine also attenuated the phentolamine-resistant pressor response to ESNS. In SHR mesenteric vasculatures preloaded with [3H]-NE, cilnidipine (10(-7) M) as well as omega-conotoxin significantly inhibited the 3H overflow evoked by periarterial nerve stimulation. In radioligand binding experiments, cilnidipine inhibited [125I]-omega-conotoxin binding to rat synaptosomes, but it did not inhibit [3H]-prazosin binding to rat cortex membranes. These results suggest that cilnidipine may reduce electrically stimulated NE release from the sympathetic nerve endings of SHR vasculatures probably through its N-type Ca channel blocking action and that cilnidipine may also inhibit the vasoconstriction induced by ATP released concomitantly during nerve stimulation.

Radioimmunodetection of human leukemia with anti-interleukin-2 receptor antibody in severe combined immunodeficiency mice

Anti-Tac monoclonal antibody recognizes human interleukin-2 receptor, which is overexpressed in leukemic cells of most adult T-cell leukemia (ATL) patients. To examine the potency of anti-Tac for targeting of ATL, biodistributions of intravenously administered 125I- and 111In-labeled anti-Tac were examined in severe combined immunodeficiency (SCID) mice inoculated with ATL cells. Significant amounts of radiolabeled anti-Tac were found in the spleen and thymus. The trafficking of ATL cells in SCID mice was detected using 111In-oxine-labeled ATL cells. These results were coincident with the histologically confirmed infiltration of ATL cells. The radiolabeled anti-Tac seemed potent for targeting of ATL.

Immunoscintigraphy of colorectal cancer using 111In-labeled monoclonal antibody to mucin

A murine monoclonal antibody MLS102 recognizes sialosyl-Tn antigen in mucin and immunohistochemically reacts with more than 80% of colorectal cancer tissues. The purpose of this study was to assess the usefulness of this monoclonal antibody for the immunoscintigraphy of colorectal cancer. Planar and SPECT images were obtained on day 2 or day 3 after injection of 2 mg and 74 MBq 111In-labeled MLS102 antibody into 17 patients with colorectal cancer. Nine of 11 primary tumors and 4 of 6 locally recurrent tumors were detected. Positive images were obtained in all tumors larger than 4.5 x 2.7 cm. Three tumors of less than 2.5 cm and 1 recurrent tumor, which was missed by other imaging modalities, were negative. There were no adverse reactions. Human anti-(mouse Ig) antibody developed in 4 patients. Although improvement of detectability for smaller tumors needs to be pursued, the antibody MLS102 is potentially promising for use in immunoscintigraphy of colorectal cancer.

3D-spiral CT of multiple exostoses

We report pre- and post-operative three-dimensional (3D)-spiral CT images in a patient with multiple exostoses. Images of 3D-CT, which were performed using the integrated 3D software of the CT system, showed the exact shapes and locations of the individual tumors around the knee joint in comparison with the surgical findings and resected specimen. 3D-spiral CT images of multiple exostoses would be useful for the planning of surgical procedure.

Uptake of pentavalent technetium-99m dimercaptosuccinic acid in idiopathic synovial chondromatosis

We reported two Tc-99m(V) DMSA scintigrams in patients with idiopathic synovial chondromatosis which affected the metacarpo-phalangeal joint and shoulder joint. Tc-99m(V) DMSA accumulated markedly and diffusely in the tumor. Tc-99m(V) DMSA scintigraphy would be valuable for deciding the optimal site for biopsy.

Three-dimensional display of cardiac structures using reconstructed magnetic resonance imaging

It is sometimes difficult to understand the three-dimensional (3D) relationship of cardiac and mediastinal structures despite advances in magnetic resonance (MR) imaging techniques. We present a low-cost system for 3D reconstruction of the major mediastinal structures by processing the MR imaging data on a NeXT workstation. MR images of multisection, multiphase, spin-echo techniques stored in a picture archiving and communication system (PACS) data base were used for the reconstruction. The computer program obtained the contours of the multiple components of the mediastinal structures by the combination of automatic and manual procedure. The bundled software of a 3D kit was used for surface rendering of hidden surface removal, shading of the visible parts of the surfaces, perspective transformation, and motion parallax by rotation of the surfaces. 3D reconstruction was performed in 15 patients with cardiac diseases, and the 3D-reconstructed images were compared with the plain chest x rays of the patients. The 3D presentation clearly showed the complex anatomy of cardiovascular diseases and helped elucidate the misconceptions in the interpretation of the plain chest x rays. Our 3D images are used for education and should be viewed by medical students and beginners in radiology at an individual pace with plain chest radiographs, MR images, and legends. Although applied to the heart and the great vessels in this report, this system is also applicable to other structures.

Bronchodilator and cardiovascular effects of NKH477, a novel water-soluble forskolin derivative, in guinea pigs

The bronchodilator and cardiovascular effects of NKH477 (6-(3-dimethylaminopropionyl)forskolin hydrochloride) were evaluated. In anesthetized guinea pigs, i.v. bolus injections of NKH477 (1-100 micrograms/kg) inhibited the bronchoconstriction induced by inhaled leukotriene D4, increased the heart rate (HR) and decreased the diastolic arterial blood pressure (DBP) in a dose-dependent manner. The bronchodilator effect of NKH477 was 1500 times more potent than that of aminophylline and 17 times less potent than that of isoproterenol. The selectivity of NKH477 for bronchodilation vs an increase in HR was 15 times higher than that of isoproterenol and similar to that of aminophylline; and vs a decrease in DBP, the selectivity was 4 times higher than that of aminophylline and similar to that of isoproterenol. I.v. infusion of NKH477 (0.1-3 micrograms/kg/min) for 2 hr dose-dependently inhibited the bronchoconstriction induced by i.v. histamine. Isoproterenol (0.1 microgram/kg/min, i.v.) enhanced the bronchoconstriction after termination of the infusion, whereas NKH477 did not. In conscious guinea pigs, inhalation of NKH477 (0.1-5 mg/ml) concentration-dependently inhibited the bronchoconstriction induced by inhaled histamine, and a high concentration of NKH477 (35.4 mg/ml) increased the HR. The bronchodilator effect of inhaled NKH477 was 15 times less potent than that of isoproterenol. The selectivity of inhaled NKH477 was similar to that of isoproterenol. These results indicate that NKH477 may be useful as a bronchodilator.

Breakdown of self-tolerance by intrathymic injection of a T-cell line inducing autoimmune gastritis in mice

Autoimmune gastritis (AIG) develops spontaneously in BALB/c mice thymectomized 3 days after birth (3d-Tx). We first confirmed our previous observations that CD4+ splenic T cells in AIG mice induced AIG in nu/nu mice, while those in normal mice suppressed the development of the disease. In addition, we found that a quantitative balance between these effector (Te) and suppressor (Ts) T cells determined either onset or prevention of the disease. Peripheralization of Ts seemed to begin around 3 days after birth, since the incidence of AIG in mice that underwent Tx 6 days after birth (6d-Tx) decreased markedly, compared with that of 3d-Tx mice; 12% in the former, while 79% in the latter. Notably, Ts existed in the 6d-Tx mice that escaped AIG. We next examined the target specificity of such Ts using syngeneic parietal cells known as autoantigens and two kinds of T-cell lines established from an AIG mouse; one is gastritis inducible in vivo, termed A-II, while another is not, named AC-II. Intrathymic injection of parietal cells into mice 3 days after birth followed by 6d-Tx completely prevented the development of AIG. In contrast, injection of irradiated A-II, but not AC-II cells resulted in AIG in 67% of the mice. No autoimmune oophoritis (AIO) was induced in female mice, implying that the breakdown of tolerance is organ specific. Taken together, peripheral tolerance for organ-specific autoantigens seems to be maintained by CD4+ Ts responding to Te, which induces the disease.

Involvement of muscle by malignant lymphoma: MR and CT appearances

OBJECTIVE

The purpose of this study is to investigate the CT and MR findings of muscular involvement by malignant lymphoma and identify the CT and MR features that may assist in their diagnosis.

MATERIALS AND METHODS

Magnetic resonance imaging was performed on four patients (five lesions) with pathologically proven non-Hodgkin lymphoma using a 1.5 T unit (Cases 1, 2, and 4) and a 0.5 T scanner (Case 3). Computed tomography scans were carried out on three patients (Cases 1, 3, and 4).

RESULTS

The lesions that extended along muscle fascicles with preserved fat planes looking like swelling of the muscle were of slightly hyper- to isointensity relative to uninvolved muscles on T1-weighted images, of hyperintensity on T2-weighted images, and of low or isodensity on CT. Microscopically, lymphoma cells were seen clustering among normal and atrophic muscle fibers in a biopsy specimen of one patient. The lesions enhanced relatively homogeneously after Gd-DTPA injection. In three cases, vessels were coursing through the lesion on MRI and in two cases on enhanced CT.

CONCLUSION

Magnetic resonance imaging proved useful to show the extension of involvement of muscular lymphoma compared with CT. The diagnosis of infiltration of muscle by lymphoma is entertained when a lesion of relatively homogeneous intensity and density extends along the muscle fascisles without obliteration of the fat planes and especially when vessels are identified within the lesion.

Diagnostic value of Tc-99m (V) DMSA for chondrogenic tumors with positive Tc-99m HMDP uptake on bone scintigraphy

Technetium-99m (V) DMSA scintigraphy was performed in 17 patients with 37 chondrogenic tumors (13 osteochondromas, 14 enchondromas, and 10 chondrosarcomas) that had previously shown uptake of Tc-99m HMDP. Technetium-99m (V) DMSA showed high uptake by all chrondrosarcomas, but low or no uptake always indicated benign chondrogenic tumors. Technetium-99m (V) DMSA scintigraphy may be superior to Tc-99m HMDP scintigraphy for distinguishing benign and malignant chondrogenic tumors, and could also be useful for diagnosing the malignant transformation of chondrogenic tumors.

Development of autoreactivity and changes of T cell repertoire in different strains of aging mice

Physiological changes with increasing age are generally accompanied by disorders of immunity, including autoaggression which can be seen in some syngeneic host-versus-graft reactions provoked when responder and stimulator cells are of different ages. The magnitude of the response, however, varies with the strain of mice. Footpad injection of irradiated spleen cells from 1-year-old, but not from 2-month-old, BALB/c mice (H-2d) into syngeneic young mice evoked popliteal lymph node-swelling, but this was not the case in DBA/2 (H-2d) mice. Therefore, the generation of autoreactivity was thought to be closely related to the change of T cell repertoire with age in the former strain of mice. At around 1 year of age, when only a small reduction in T cell number was observed and when a slight increase in CD8+ T cells in the periphery caused the CD4/CD8 ratio to be lower than in young mice, the proportion of V beta 8+ cells in BALB/c mice started to increase, increasing from 16% in the young to 27% in 2-year-old mice (P < 0.01). On the other hand, V beta 6+ T cells remained at the same level as in young mice throughout life. The increasing fraction of V beta 8+ T cells was characterized by a low density of T cell receptors (TcR) and it was more conspicuous in the spleen than in the peripheral blood in mice more than 1 year of age. A shift to a TcR-low population in V beta 8+, T cells was followed in a few months by a shift in V beta 6+ T cells. Although both the change of T cell repertoire and development of autoaggression may be parameters of aging, no direct correlation was demonstrated between them in experiments with cross-hybrids and recombinant inbred strains of BALB/c and DBA/2 mice. Probably, the two parameters are genetically and independently controlled. All the data taken together indicate that T cells undergo V beta-TcR-restricted changes during their life history, depending on their genetic background.