Insular component as a risk factor of thyroid carcinoma

Forty-four thyroid carcinomas with an insular component (IC) were reviewed from 2457 tumors diagnosed as papillary (PC) or follicular carcinoma (FC). These tumors were classified as FC with an IC (FCIC; 30 cases) and PC with an IC (PCIC; 14 cases). Both tumors were composed of solid cell nests in some areas and had a tendency toward a characteristic nuclear size: FCIC had a small nucleus and PCIC contained a nucleus of an intermediate type or a large nucleus similar to that of PC, although there were numerous tumors with an exceptional nuclear size. The mean age and tumor diameter were the highest and largest in FCIC, respectively, followed by PCIC. Among the 44 cases, 17 patients died of the disease, two were alive with the disease and 18 were alive without the disease. From 13 clinicopathological factors, the presence of an IC, age, non-encapsulation, tumor size, vascular invasion and necrosis were found to be independent variables for actual prognosis of FC and PC based on univariate analysis followed by multivariate analysis. The results of the present study indicate that the presence of an IC is an independent aggressive prognostic factor for patients with PC and FC.

Accumulation of apolipoprotein E and beta-amyloid-like protein in a trace of the hippocampal CA1 pyramidal cell layer after ischaemic delayed neuronal death

We found that apolipoprotein E (apo E) accumulates in a trace of the hippocampal CA1 pyramidal cell layer within 6 months after 5 min ischaemia. Intense methenamine-silver (M-S) stainings were seen in the entire CA1 subfield 3 months after ischaemia. The M-S staining pattern may imply the appearance of soluble A beta-like proteins. The apo E-positive trace was also positively stained with anti-beta-amyloid (A beta) protein antibodies, but not with anti-beta-amyloid protein precursor (APP) antibodies. These results suggest that A beta-like protein accumulates in ischaemic brain after neuronal cell death. Adjacent reactive astrocytes showed both apo E- and A beta-immunoreactivities. These astrocytes may be involved in the clearance of apo E- and A beta-positive material. We presume that the coincident distribution pattern for apo E- and A beta-immunoreactivity implies formation of the insoluble and stable A beta-apo E complex which is known to exist in the brain of individuals with Alzheimer's disease. The ischaemic model may be useful in studying apo E and A beta deposition in the brain.

Host-parasite arms race in mutation modifications: indefinite escalation despite a heavy load?

If constantly changing genotypes are favorable in host and parasite coevolution, an indefinite escalation of mutation rates would result despite heavy mutational loads. We theoretically study this possibility by examining the mutation modifier dynamics of host and parasite that engage in genotype-specific epidemiological interaction. In the first model, we study the evolutionarily stable (ESS) mutation rate or switching rate if two alleles in a single locus are subjected to frequency-dependent selection favoring the rarer of the two. Mutation modifier locus is either tightly linked or unlinked to the selected locus. Sufficiently strong frequency-dependent selection may cause cycles in allele frequencies and a modifier with higher mutation rate enjoys the long-term advantage by randomizing the genotype of their offspring. Through the repeated events of invasion and replacement of mutation modifiers, the mutation rate continues to increase until the allele frequencies are stabilized. If some fraction of mutations are deleterious, there is no longer a pure ESS mutation rate: the evolutionarily stable population then consists of multiple strains concerning mutation modifier, typically one with a very high mutation rate and the other with a very low rate, stably coexisting and fighting off invasion by any other modifiers. These results are almost independent of the linkage between the selected and the modifier loci. In the second model, we consider the joint evolution of host and parasite mutation modifiers, assuming that a specific pair of host and parasite genotype densities change following the Nicholson-Bailey type model. If there is no cost of deleterious mutations, mutation rates of both species are escalated indefinitely by modifier evolution until they completely suppress the fluctuation of genotype densities. However, a small cost of deleterious mutation is enough to collapse this coevolutionary equilibrium of inflated mutations. Typical coevolutionary outcome is that the parasite mutation rate is accelerated to a high level; whereas the host mutation rate is driven to zero. Extension of our results to host-parasite coevolution of recombination modifier evolution is discussed.

Oncofetal expression of blood group-related antigen on morules in thyroid carcinoma

Morule formation in association with characteristic biotinrich 'optically clear nuclei' were found in 7 of 2514 cases of thyroid carcinoma. The seven patients were all young females aged from 20 to 36 years who were suffering from either papillary carcinoma (six cases) or follicular carcinoma (one case). The ABH (O) blood group (BG) types were A in three, AB in two and H(O) in two patients. Immunohistochemical study revealed that ABH(O) and Lewis BG antigens were expressed more specifically on morules than on ordinary neoplastic cells of papillary or follicular carcinoma. Lewis BG antigens tested in the present study were as follows: CA50, CA19-9, stage-specific embryonic antigen 1 (SSEA-1), and sialyl SSEA-1. Ulex europaeus agglutinin I (UEA-I) histochemistry showed a positive reaction on all the morules of blood groups A and H(O) patients, but yielded completely negative results on the morules of type AB patients. Sequential digestion by neuraminidase and alpha-galactosidase unmasked the reactivity for UEA-I even on the morules of type AB patients. The consistent reactivity for UEA-I on the morules seemed to be related to specific expression of BG antigens, which were characterized as oncofetal expression. It is suggested that the morules in thyroid carcinoma might be a kind of fetal component induced by the differentiation of the neoplastic cells to the stage of immature embryonic cells.

Transforming growth factor-beta inhibits interferon-gamma secretion by lymphokine-activated killer cells stimulated with tumor cells

The effect of transforming growth factor-beta (TGF-beta) secreted by glioblastoma (T98G) cells on the secretion of interferon-gamma (IFN-gamma) by lymphokine-activated killer (LAK) cells stimulated with tumor cells was investigated in cocultures of LAK and Daudi cells supplemented with T98G culture supernatant, T98G culture supernatant preincubated with anti-TGF-beta 1 and anti-TGF-beta 2 neutralizing antibodies, anti-TGF-beta 1 and anti-TGF-beta 2 antibodies, or natural human TGF-beta 1 or recombinant human TGF-beta 2. LAK cells were incubated with anti-TGF-beta 1 and anti-TGF-beta 2 antibodies, and with T98G cells of which the supernatant contained both active and latent forms of TGF-beta 1 and TGF-beta 2, with or without neutralizing antibodies. Addition of the supernatant from T98G cells to LAK/Daudi culture caused inhibition of IFN-gamma secretion by LAK cells. The inhibition was abolished by pretreatment of the supernatants with anti-TGF-beta antibodies. Addition of TGF-beta 1 and TGF-beta 2 to the LAK/Daudi culture inhibited IFN-gamma secretion by LAK cells in a dose-dependent manner. Addition of anti-TGF-beta antibodies to the LAK culture resulted in increased IFN-gamma secretion. T98G cells failed to stimulate LAK cells to secrete more IFN-gamma. Addition of anti-TGF-beta antibodies to the LAK-T98G culture resulted in increased IFN-gamma secretion by LAK cells. These results suggest that most malignant glioma cells which secrete high levels of TGF-beta can inhibit IFN-gamma secretion by LAK cells even after tumor cell stimulation.

Abnormalities of T waves in effort angina pectoris patients at rest evaluated by spatial velocity electrocardiogram

The normal shape of the T wave on the standard 12-lead electrocardiogram (ECG) is asymmetrical. The spatial velocity electrocardiogram (SVECG) is a method of recording the slope of the wave of the ECG and makes it possible to quantify the symmetry of the ECG-T wave. The aim of this study was to diagnose resting effort angina pectoris not detectable by conventional resting ECG using SVECG. We studied SVECG-T waves in effort angina pectoris patients with significant coronary artery stenosis but with normal resting ECG (AP group: 50 subjects) and in an age- and sex-matched normal controls (N group: 30 subjects). The SVECG is depicted as a simple differential wave, and all SVECG-T waves had two peaks. The first peak of the SVECG-T wave was designated as the 'a' wave and the second peak as the 'c' wave. The heights (a wave-mag, c wave-mag) and c wave-mag/a wave-mag ratio (c/a ratio) were calculated. The c/a ratio was significantly decreased in the AP group (1.52 +/- 0.29 vs 1.87 +/- 0.27, p < 0.0001). In cases below the cut off c/a ratio of 1.7, the diagnostic sensitivity, specificity and accuracy for effort angina pectoris were retrospectively evaluated to be 82%, 70% and 78%, respectively. The heights of the 'a' and 'c' waves correspond to the maximum slope of the ascending and descending limbs of the T wave on ECG. The symmetrization of the T wave on ECG is considered to occur when the c/a ratio decreases and approaches 1.0. In conclusion, the c/a ratio of the SVECG-T wave is a useful index to diagnose effort angina pectoris at rest when the resting ECG is normal.

Undifferentiated tumor originating in the cerebral dysgenetic lesion resembling fibrous cartilage: case report

A 33-year-old woman had an undifferentiated tumor originating in the cerebral dysgenetic lesion resembling fibrous cartilage. She had a headache, vomiting, late-onset epilepsy and left hemiparesis. The lesion was located in the right temporal lobe on computed tomographic (CT) scan. It was totally resected and only local irradiation was performed postoperatively. Normal cortical architectures were lost in the resected specimens. Straight or curved fasciculi composed of fine collagen fibers were distributed in parallel and perpendicular to the cortical surface in the mildly eosinophilic hyaline matrix. Hypertrophic astrocytes were scattered with low cellularity in these abnormal cortices. Clusters of tumor cells were observed in a few areas. The tumor cells, having oval and relatively vesicular nuclei with a few prominent nucleoli and basophilic well-circumscribed narrow cytoplasm, had proliferated diffusely with a cobblestone appearance. Immunohistochemical and electron microscopic investigations demonstrated no evidence of specific differentiation, either. There were 14.5 mitotic figures/high power field on average and most nuclei of the tumor cells were strongly positive for proliferating cell nuclear antigen (PCNA). Moreover, subarachnoid dissemination of the tumor cells were apparent in a few areas. Nevertheless the patient returned to work and no recurrence was observed for 10 years postoperatively. We concluded that neoplastic transformation occurred de novo in the dysgenetic cortex.

Body surface mapping criteria for diagnosis of left ventricular hypertrophy associated with complete right bundle branch block

The standard electrocardiographic (ECG) criteria for left ventricular hypertrophy are unreliable in patients with complete right bundle branch block. This study was undertaken to formulate criteria for diagnosing these patients by using body surface mapping. The echocardiographic left ventricular mass was calculated by the Penn method from M-mode measurements. Of 56 patients, 27 were defined as having left ventricular hypertrophy with a left ventricular mass of 215 g or more. Isopotential and isointegral maps of the QRS complex were observed. The QRS isointegral maps were separated into two parts at the end of the downstroke of the initial R wave of vector spatial magnitude. The body surface mapping criteria with the highest sensitivity were EPmax (maximum of early part of the QRS) 45 microV.s or greater (sensitivity 93%, specificity 90%), EPmax/d (EPmax averaged by EP duration) 0.8 mV or greater (sensitivity 93%, specificity 97%), and Max (initial maximum) 2.2 mV or greater (sensitivity 89%, specificity 90%). These results suggest that body surface mapping is a useful technique in diagnosing patients with left ventricular hypertrophy and right bundle branch block.

A 15 year follow-up study of patients with non-insulin dependent diabetes mellitus (NIDDM) in Osaka, Japan. Long-term prognosis and causes of death

A 15 year follow-up study of diabetic patients was performed in Osaka, Japan. The subjects studied were 1939 patients with non-insulin dependent diabetes mellitus (NIDDM), of whom 1000 (51.5%) were alive, 880 (45.4%) had died and 59 (3.0%) were untraceable at the end of 1993. The mortality rate per 1000 person-years of the subjects increased from 28.94 in 1960-1984 to 35.74 in 1985-1993, but the ratio of numbers of observed to expected deaths (O/E ratio) declined from 1.77 to 1.52 for the corresponding periods, suggesting an improvement in the prognosis for diabetic patients, with the exception of patients 65 years or over at the time of entry. Cerebro-cardiovascular and renal diseases were major causes of death, accounting for 48.4% of all deaths. In particular, disease of the heart was the cause of death in 20.5% of all deaths, cerebrovascular disease in 14.5% and renal disease in 12.0%. The O/E ratio was 11.30 for renal disease, which was remarkably high. The O/E ratios were 1.48 for malignant neoplasms, 3.02 for cancer of the liver and 2.15 for cancer of the pancreas. In the subjects less than 65 years of age at entry, a significant decrease in the O/E ratio for overall deaths, malignant neoplasms, disease of the heart, cerebrovascular disease and renal disease was observed, but no notable difference in the O/E ratio for ischemic heart disease was found between the periods 1960-1984 and 1985-1993. By contrast, in the case of subjects 65 years or more at entry, the O/E ratios for overall deaths, malignant neoplasms, disease of the heart, ischemic heart disease and cerebrovascular disease increased markedly in the later period, while there was a considerable decline in renal disease indicated during this period. The analysis suggested a structural change in causes of death of Japanese diabetic patients in recent years, with a relative increase in ischemic heart disease and a relative decrease in renal disease.

[Two cases of pseudomyxoma peritonei that responded to intraperitoneal administrations of a combined CDDP, 5-FU and MMC therapy]

Pseudomyxoma peritonei, which is the seeding of the peritoneum by mucin-secreting metastatic deposits and the filling of the peritoneal cavity by these secretions, is a malignancy that even after excision of the metastatic areas has a poor prognosis, since no effective therapy has yet been established. Herein, we report two cases of pseudomyxoma peritonei that responded to a combined postsurgical therapy consisting of CDDP, 5-FU and MMC. Case 1 involved a 56-year-old woman who underwent an appendectomy, a bilateral ovariectomy, and an omentectomy, due to pseudomyxoma peritonei. Further, a subcutaneous implant-type reservoir was sited intraperitoneally for postoperative chemotherapy. At 30 days after surgery, therapy commenced, consisting of 100 mg of CDDP and 20 mg of MMC administered intraperitoneally and 1,000 mg of 5-FU continuously infused by intravenous drip. This combined therapy was given for 5 days and repeated 8 times. As a result, the serum CEA value, which had elevated postoperatively, fell within the respective normal range, and at 4 years postoperatively, this patient remains alive. Case 2 concerns a 59-year-old woman who underwent an appendectomy, a right ovariectomy, and an omentectomy due to pseudomyxoma peritonei, and was postoperatively given 50 mg intraperitoneal administration of CDDP. She received 2 courses of postoperative chemotherapy similar to that given case 1 but with the addition of a 500 mg 5-FU intraperitoneally. At 8 months postoperatively, she is alive and disease-free. Given the above results, intraperitoneal administrations of this combined CDDP-5-FU-MMC therapy may be effective for patients with pseudomyxoma peritonei.

E-cadherin expression in human breast cancer cells suppresses the development of osteolytic bone metastases in an experimental metastasis model

The molecular mechanisms by which human cancer cells spread to bone are largely unexplored. The process likely involves cell adhesion molecules (CAMs) that are responsible for homophilic and heterophilic cell-cell interactions. One relevant CAM may be the calcium-dependent transmembrane glycoprotein E-cadherin. To investigate the involvement of E-cadherin in breast cancer metastasis to bone, we used an in vivo model in which osteolytic bone metastases preferentially occur after injections of cancer cells directly into the arterial circulation through the left ventricle of the hearts of nude mice. We have found that E-cadherin-negative human breast cancer cells MDA-MB-231 (MDA-231) develop radiographically detectable multiple osteolytic bone metastases and cachexia in this model. However, MDA-231 breast cancer cells that were transfected with E-cadherin cDNA showed a dramatically impaired capacity to form osteolytic metastases and induce cachexia. Histological and histomorphometrical analyses of bones of mice bearing mock-transfected MDA-231 revealed aggressive metastatic tumor, whereas metastatic tumor burden was significantly decreased in the bones of mice bearing E-cadherin-expressing MDA-231. Nude mice bearing E-cadherin-transfected MDA-231 breast cancer cells survived longer than mice bearing mock-transfected MDA-231 breast cancer cells. Anchorage-dependent and -independent growth in culture and tumor enlargement in the mammary fat pad of nude mice were unchanged between mock-transfected and E-cadherin-expressing MDA-231, suggesting that these differences in metastatic behavior are not due to an impairment of cell growth and tumor-igenicity. Our results show the suppressive effects of E-cadherin expression on bone metastasis by circulating breast cancer cells and suggest that the modulation of expression of this CAM may reduce the destructive effects of breast cancer cells on bone.

Patterns of genetic polymorphism maintained by fluctuating selection with overlapping generations

We study the form of polymorphisms that can be maintained by the joint effects of generation overlap and randomly fluctuating selection, acting on a quantitative trait affecting offspring viability. The genetic system can be single locus or multilocus, haploid or diploid. Selection is assumed to be stabilizing with a randomly fluctuating optimum, and we assume additive allelic effects without epistasis. For fluctuations above a certain threshold, nonzero genetic variance is maintained in an evolutionarily stable population. Our model allows a continuum of alleles with arbitrary effects at each locus. Nonetheless, the genotype distribution in an evolutionarily stable population is discrete--a polymorphism of a few alleles with distinctly different effects--and often involves only a pair of alleles at each locus. The form of the genotype distribution depends on the number of loci affecting the trait, and on the kurtosis of the distribution of the phenotypic optimum theta. If the trait is affected by several loci, the number of polymorphic loci increases with increased variance of fluctuations in selection. For distributions of theta with negative kurtosis (i.e., lower kurtosis than a Gaussian) the number of polymorphic loci increases gradually (0-->1-->2--> ...M), and the genetic variability is in the form of a few diallelic or triallelic loci with alleles of large effect. For distributions with positive kurtosis, the increase is abrupt (0 -> many) and involves many diallelic loci. These results do not fit the conventional multivariate Gaussian or near-Gaussian models for quantitative traits, but may partially explain recent findings that heritable variation in natural populations is often due to genes of large effect.

Recurrent anaplastic ganglioglioma: pathological characterization of tumor cells. Case report

A total resection of a left frontal lobe tumor in a 26-year-old man revealed differentiated ganglioglioma with small foci of atypical glial cells exhibiting mild atypia. Six and one-half years later, a large, well-demarcated tumor recurred; at that time, histological analysis revealed both typical ganglioglioma and highly cellular anaplastic areas, the latter predominating. Although the patient subsequently underwent total and subtotal resections, radiation therapy, and chemotherapy, tumors continued to recur at progressively shorter intervals and he died at the age of 35 years. Biopsies of tissue obtained at the last three resections and the autopsy revealed only anaplastic tumor cells. Routine histological examinations indicated that these tumors were uniformly composed of undifferentiated cells. However, pathological studies using immunohistochemical analysis, electron microscopy, and immunoblot analysis demonstrated that a small number of recurrent anaplastic cells had astrocytic features. Results of Ki-67/MIB-1 labeling and silver nucleolar organizer region counts for those cells were high for glial tumors. A retrospective study of the initial tumor showed slightly high MIB-1 labeling for atypical glial cells. This case is characterized by pathological findings of recurrent tumors that correspond to an unusual form of malignant glioma exhibiting slight astrocytic differentiation. The present case suggests that a longer follow-up period ( > 5 years) is necessary in cases of ganglioglioma with mild atypia and that careful examinations, including proliferating potential analysis of initial tumor cells, could be important for the diagnosis and treatment of ganglioglioma.

[Serum sodium imbalance in the bedridden elderly. Part One: Realities and problem of management]

Symptoms and other abnormalities associated with serum sodium imbalance were studied in bedridden elderly and healthy elderly subjects. 1. A significantly higher number of the bedridden elderly suffered from chronic wasting disease. 2. The average serum sodium concentration in bedridden elderly subjects was significantly lower than in healthy subjects, as was the sodium intake and the sodium content in urine, which indicate that the bedridden elderly subjects suffered from chronic sodium deficiency. 3. The bedridden elderly subjects had high levels of plasma PRA and antidiuretic hormone, and their aldosterone levels were low, which indicate that their condition was associated with a decrease in available circulating plasma, hypersecretion of antidiuretic hormone, and a decline in the ability to retain sodium. 4. Measurement of 24-hr creatinine clearance, albumin, and beta 2-microglobulin in urine revealed that bedridden elderly subjects had high levels of renal dysfunction, the result of which may a disturbance in water excretion. Abnormalities in serum sodium levels in the bedridden elderly subjects were related to a chronic deficiency in sodium intake, which reduced their ability to maintain sodium levels and impaired their renal function. Iatrogenic factors are likely to play an important role in the genesis of this condition, and should be taken into account in during management.

A monoclonal antibody that specifically recognizes a novel mitochondrial protein of human astrocytes

We established a monoclonal antibody to human astrocytes using a human glial cell-rich fraction as the immunogen. The antibody, named PRAS-4, specifically labeled populations of astrocytes in a fine granular manner immunohistochemically. In formalin-fixed, paraffin-embedded tissue sections, PRAS-4-positive astrocytes were extensively distributed in the gray matter of the central nervous system, namely the cerebral cortex, basal ganglia, diencephalon, midbrain, various nuclei of the brain stem, cerebellar cortex and nuclei, and spinal cord. In the white matter, a few positive astrocytes were located mostly in the perivascular area. The reaction was lost after protease digestion and it resisted periodic acid, suggesting that the epitope is of a protein. The molecular weight of the antigen was estimated as 62 kDa. Ultrastructurally, the immunoreaction was localized on the outer and inner membranes of astrocytic mitochondria, and unlabeled mitochondria coexisted in the same cells. Extra-mitochondrial regions were not stained. PRAS-4 preferentially labeled astrocytes of the protoplasmic type, and may be applicable to studies on the development, specific functions and neoplasms of astrocytes.

[Simultaneous aortic root and total arch graft replacement in a patient with aortitis syndrome]

The patient was a 45-year-old female diagnosed with aortitis syndrome and aortic regurgitation (AR). She had been taking steroid therapy since 1975. She had recently developed congestive heart failure due to AR while both the ascending aorta and aortic arch were enlarged. She had no inflammatory reaction on admission. An aortogram showed heavy dilation of both the ascending aorta and aortic arch and maximum diameters was 11 cm in the ascending aorta and 4.5 cm in the descending aorta. There was an obstruction of the left subclavian artery. Moderate AR was seen on an echocardiogram. She had a simultaneous graft replacement of aortic root and total arch. The aortic root was replaced with composite graft and coronary arteries were implanted using Carrel's patch technique, and the aortic arch was also replaced with a graft with two side branches. The postoperative course was uneventful without complication of cerebral infarction or paraplegia. The postoperative aortogram showed stenosis of the left carotid artery, but no abnormality of the coronary orifices and graft anastomosis. She returned home with disappearance of symptoms of congestive heart failure.

Decreased L-selectin expression in CD34-positive cells from patients with chronic myelocytic leukaemia

Abnormal adhesive interaction between bone marrow stroma and progenitors, one of the causes of unregulated proliferation in chronic myelocytic leukaemia (CML), may be caused by some alterations in adhesion molecules on CML progenitors. We investigated the expression of adhesion molecules (CD44, VLA-5, VLA-4, LFA-1, ICAM-1, L-selectin and c-kit) on bone marrow CD34++ cells from 16 CML patients by three-colour flow cytometry. The mean percentage of cells expressing L-selectin in the CD34++CD38+(or)++ fraction from untreated CML patients was significantly lower, and that in the CD34++CD38- fraction tended to be lower than that from normal controls. Among 11 CML patients treated with interferon-alpha (IFN-alpha), the mean percentage of the cells expressing L-selectin in the CD34++CD38- fraction from three patients with a low percentage of Ph1(+) cells in bone marrow was significantly higher than that from five patients with a high percentage of Ph1(+) cells. In addition, L-selectin expression rate was inversely correlated to the percentage of Ph1(+) cells. There was no significant difference between the untreated patients and normal controls with regard to the expression rates of the other adhesion molecules in each CD34++ fraction except LFA-1. These data suggest that decreased L-selectin expression in CML CD34++ cells reflects one of the features of malignant CML progenitors.

Malignant fibrous histiocytoma of the lateral wall of the orbit

A 58-year-old male presented with malignant fibrous histiocytoma originating from the lateral wall of the orbit, manifesting as left exophthalmos and diplopia on left lateral gaze. Magnetic resonance (MR) imaging demonstrated the tumor extending into the left orbit and under the temporalis muscle. The tumor was isointense with muscle on T1-weighted MR images and was surrounded by a low-intensity rim, which was proved to be the capsule after histological examination. The tumor was completely removed after detaching the lateral orbital rim and zygomatic arch using the dismasking flap method. He underwent one course of CYVADIC chemotherapy and has demonstrated no recurrence for 1 year and 6 months postoperatively.

Accumulation of beta-amyloid fibrils in pancreas of transgenic mice

Some forms of familial Alzheimer's disease are caused by mutations in the amyloid beta protein precursor (beta APP), and there is excellent evidence that these mutations foster amyloid deposition by increasing secretion of total amyloid beta protein (A beta) or the highly amyloidogenic A beta 1-42 form. These observations provide a powerful rationale for developing an animal model of AD by generating transgenic mice in which cerebral amyloid deposition is induced by A beta overproduction. To produce substantial A beta in vivo, we generated mice expressing the transgene of signal peptide and 99 residues of carboxyl-terminal fragment (CTF) of beta APP under control of the cytomegalovirus enhancer/chicken beta-actin promoter. The transgenic mRNA was detected in many tissues of these mice, but the levels of transgenic mRNA, CTF, and A beta did not correlate well indicating that tissue-specific posttranslational processing may play an important role in determining the amount of A beta that accumulates in various tissues. A beta was detected biochemically in brain, kidney, and pancreas with the largest amount present in pancreas. In transgenic plasma, there was a marked accumulation of human A beta 1-40 and A beta 1-42(43) to levels over 30-times those observed in normal human plasma. Thus, the transgenic mice produce and secrete considerable A beta. Despite this increase in A beta secretion and the elevated A beta in brain, immunohistochemistry revealed no consistent cerebral A beta deposition. In pancreas, however, intracellular A beta deposits were detected immunohistochemically in acinar cells and interstitial macrophages, some of which showed severe degeneration. In addition, examination of these cells by immunoelectron microscopy revealed many putative amyloid fibrils (7-12 nm) that were stained by anti-A beta antibodies. Overall, our findings indicate that tissue-specific posttranslational processing may play a pivotal role in A beta production and amyloid fibril formation in vivo. By carefully analyzing the changes that occur in the transgenic mice described here as compared to the transgenic line that has recently been shown to form extracellular amyloid plaques in brain, it may be possible to gain considerable insight into the factors that determine the location and amount of A beta that accumulates as amyloid.

In vivo behavior of liposomes modified with a novel galactosyllipid derivative

We studied the in vivo behavior of galactosyllipid-modified liposomes for targeting the asialoglycoprotein receptor present on the surface of liver parenchymal cells. We examined the effects of the lipid composition of liposomes on the in vivo behavior of galactosyllipid-modified liposomes, and found good accumulation in the liver of liposomes of a high cholesterol content and liposomes made of lipids of a high gel-liquid crystalline phase transition temperature. The amount of modification with the galactosyllipid derivative required for effective targeting to the liver was found to be more than 5% of the total lipids. The concentration of galactosyllipid-modified liposomes was lower than that of control liposomes in all the organs except for the liver, showing high selectivity of galactosyllipid-modified liposomes for the liver. Hepatic accumulation of liposomes was inhibited by preinjection of asialofetuin. This result suggests that hepatic accumulation of ¿8-(2-hexadecyloctadecanoylamido)-3,6-dioxaoctyl¿-beta-D-gal actoside (Gal-t-psa) liposome was involved with the asialoglycoprotein receptor in the liver. Therefore, it was concluded that our neogalactolipid-modified liposomes are useful for selective delivery to the liver.