Analysis of the c-FOS gene on chromosome 14 and the promoter of the amyloid precursor protein gene in familial Alzheimer's disease

The c-FOS gene product, a putative transacting transcriptional regulator of the amyloid precursor protein (APP) gene, is a candidate locus for the familial Alzheimer's disease (FAD) mutation on chromosome 14 (FAD14). In light of this functional relationship, we investigated the nucleotide sequence and segregation of c-FOS and the nucleotide sequence of the 5' APP promoter. Single-stranded conformational polymorphisms (SSCPs) in the c-FOS gene revealed that c-FOS closely cosegregates with the FAD14 gene but does not show allelic association with FAD. A conservative third-position T-->C mutation was demonstrated in exon 2 (codon 84) of c-FOS, and a C-->G substitution was detected at -209 bp in the 5' promoter of APP. Neither were unique to FAD and are unlikely to be pathogenic or secondary modifiers of the FAD phenotype. We conclude that the c-FOS open reading frame is probably not the site of the FAD14 locus, but we cannot exclude the existence of modifier loci on chromosome 21.

Effects of diethyl spermine analogues in human bladder cancer cell lines in culture

The biochemical and antiproliferative effects of two recently developed N-alkylated analogues of naturally-occurring polyamines, N1,N14-diethylhomospermine (DEHSPM) and N1,N11-diethylnorspermine (DENSPM), were investigated in two human transitional cell carcinoma (TCC) lines, T24 and J82. Parallel studies with the ornithine decarboxylase enzyme inhibitor alpha-difluoromethylornithine (DFMO) were included for comparison. DENSPM displayed greater antiproliferative activity than DEHSPM in both TCC cell lines. Both analogues were strikingly more potent than DFMO. DEHSPM and DENSPM suppressed the activity of the major biosynthetic enzymes, ornithine decarboxylase and S-adenosylmethionine decarboxylase. However, differences in the resulting polyamine depletion suggest that the substantial antiproliferative activity of these analogues may result from mechanisms other than polyamine depletion. The greater polyamine depletion seen with DENSPM is thought to result from its striking induction of spermidine/spermine N1-acetyltransferase. DENSPM is an attractive agent for further preclinical and clinical development, possibly as a chemopreventive agent, in TCC of the bladder.

Femoral version and neck shaft angle

We measured femoral anteversion by the Kingsley-Olmsted method in 24 unpaired, dry femurs. When the head and neck of the same femurs were measured by computed tomography (CT) scan, measurement was 5 degrees less than the Kingsley-Olmsted method, whereas ultrasound of the head and neck was 5 degrees higher. An anterior flat plane was also defined to help measure anteversion in patients with a high neck shaft angle. Physical and ultrasound measurement correlated well with the previous measurement by the Kingsley-Olmsted method and CT scan of anteversion. Although measurement by CT scan and ultrasound are different their results are both reproducible and measure the same parameters; however, ultrasound measurement yields a number approximately 10 degrees higher.

Mutation of the gene for the human lysosomal serine protease cathepsin G is not the cause of aberrant APP processing in familial Alzheimer disease

Recent genetic linkage studies have implicated a gene on chromosome 14 in the pathogenesis of FAD. The identity of this gene remains unknown but it has been speculated that it may be involved in the cellular processing of the amyloid precursor protein (APP). We have analyzed the nucleotide sequence of the entire open reading frame of the cathepsin G gene located on chromosome 14q. No mutations were observed, suggesting that defects in this lysosomal protease are not responsible for aberrant accumulation of proteolytic products of APP in FAD brain tissue.

Surveillance and care of four Chinese hemophiliacs with human immunodeficiency virus (HIV) infection

Four Chinese hemophiliacs with HIV infection have been followed up in Zhejiang Province since 1985. A plan for optimal care of HIV seropositive patients was proposed, including surveillance and care; clinical follow-up and preventive education of asymptomatic HIV seropositive patients; keeping the disease confidential so as not to stir up unnecessary social unease; propaganda and health education about acquired immunodeficiency syndrome (AIDS); treatment with traditional Chinese medicines; and regular surveillance of family members and medical personnel. This plan is regarded as feasible and effective for the prevention and control of AIDS in China.

Genetic evidence for a novel familial Alzheimer's disease locus on chromosome 14

Familial Alzheimer's disease (FAD) has been shown to be genetically heterogeneous, with a very small proportion of early onset pedigrees being associated with mutations in the amyloid precursor protein (APP) gene on chromosome 21, and some late onset pedigrees showing associations with markers on chromosome 19. We now provide evidence for a major early onset FAD locus on the long arm of chromosome 14 near the markers D14S43 and D14S53 (multipoint lod score z = 23.4) and suggest that the inheritance of FAD may be more complex than had initially been suspected.

Visual functions and trace element metabolism in tobacco-toxic optic neuropathy

Visual functions and nutrition metabolic characteristics were studied in 8 subjects (16 eyes) with tobacco-toxic optic neuropathy (TTON). Their visual functions tested by psychophysical and electrophysiologic methods showed that 1: 1. central vision diminished in 16 eyes, 2. dyschromatopsias were found in 14 tested eyes, 3. bilateral symmetrical central or cecocentral scotomas were the visual field characteristics in all cases, 4. PVEP were severe abnormal in 3 spatial frequencies in all cases and 56.3% of 15' checkboard PVEP showed flat responses, which indicated the impairment of optic nerve dominated by the central field. However, the preserved visual responses could be obtained by FVEP test in 14 tested eyes even though their visual acuity were between the range of 0.02-0.2 and flat PVEP responses. The II and III wave latencies of primary stage were more prolonged than those of control group (P < 0.01), which further indicated the preferential demyelination corresponding to the papillomacular bundles, 5. ERG showed slightly attenuated amplitudes in 5 of 8 tested eyes, which indicated the secondary and mild retinal lesion. On the other hand, TTON occurred on a background of long-term, heavy smoking, drinking, emaciation and malnutrition bodies with low serum zinc level.

Expression and function of GLUT-1 and GLUT-2 glucose transporter isoforms in cells of cultured rat pancreatic islets

We have previously investigated glucose induction of glucokinase, glucose usage and insulin release in isolated cultured rat pancreatic islets (Liang, Y., Najafit, H., Smith, R. M., Zimmerman, E. C., Magnuson, M. A., Tal, M., and Mastchinsky, F. M. (1992) Diabetes (1992) 41, 792-806). Here we studied the expression and function of GLUT-1 and GLUT-2 glucose transporter isoforms, using the same system, i.e. isolated pancreatic rat islets immediately after isolation or cultured in the presence of 3 or 30 mM glucose for as long as 10 days. We found by immunofluorescence microscopy and Western and Northern blot analysis of islet extracts that GLUT-1 expression was induced in islet beta-cells in tissue culture both with low or high glucose present. The induction of GLUT-1 was specific to beta-cells but was not present in all beta-cells and was not detected in alpha-cells. GLUT-2 expression was also specific for beta-cells and was not observed in all beta-cells. Some beta-cells in culture coexpressed GLUT-1 and GLUT-2. The expression of the two glucose transporters was regulated in the opposite direction in response to glucose concentration in the culture medium. GLUT-1 was more effectively induced when glucose was low, and GLUT-2 expression was more pronounced when glucose was high in the culture media. Another difference between the two glucose transporters was that GLUT-2 expression was increased while GLUT-1 expression was decreased as culturing continued as long as 7 days. Thus, after 7 days of culture GLUT-2 expression in beta-cells was nearly the same at low and high glucose, whereas GLUT-1 was practically absent no matter what the glucose level was. In attempts to correlate GLUT-1 and GLUT-2 expression to beta-cell function glucose uptake and glucose-stimulated insulin release in fresh and cultured islets were measured. In freshly isolated islet glucose uptake was estimated to be 100-fold in excess of actual glucose use. Glucose uptake was reduced by 7-day culture to about one-third of that observed in freshly isolated islets no matter what the glucose concentration of the culture media. We conclude that in the present experimental system GLUT-1 and GLUT-2 expression and function are not closely associated with glucose usage rates or the secretory function of beta-cells.

Concordant glucose induction of glucokinase, glucose usage, and glucose-stimulated insulin release in pancreatic islets maintained in organ culture

Using cultured islets as the experimental system, this study established dosage-response and time-dependency curves of the inductive glucose effect on glucose-stimulated insulin release, glucose usage, and glucokinase activity. Glucose-stimulated insulin release in islets cultured for 1, 2, or 7 days was increased as a function of glucose concentration in the culture medium and as a function of time. Glucose usage in the cultured islets showed a close relationship with glucose concentration in the culture medium at both 2 and 7 days of culture. Glucokinase activity increased in islets cultured for 1, 2, or 7 days as a function of increasing glucose concentrations in the culture medium and as a function of time. The V(max) of glucokinase in islets cultured for 7 days in medium containing 30 mM glucose was twice the value of freshly isolated islets and was almost fivefold higher than that in islets cultured for 7 days in 3 mM glucose. The glucose induction of glucose-stimulated insulin release, of glucose usage, and of glucokinase activity were tightly correlated. The biochemical mechanisms of glucose induction of islet glucokinase were further studied. Immunoblotting with an antibody against C-terminal peptide of glucokinase showed that densities of a 52,000-kD protein band from tissue extracts of islets cultured for 7 days in 3, 12, and 30 mM glucose were 25, 44, and 270% compared with that of extract from freshly isolated islets (100%). RNA blot analysis of glucokinase mRNA demonstrated virtually the same levels in fresh islets and islets after 7 days of culture in 3 or 30 mM glucose. The adaptive response of glucokinase to glucose appears therefore to be occurring at a translational or posttranslational site in cultured islets. These data greatly strengthen the concept that glucose is the regulator that induces the activity of glucokinase, which in turn determines the rate change of glucose usage as well as glucose-stimulated insulin release from beta-cells. Thus, the hypothesis that glucokinase is the glucose sensor of beta-cells is strengthened further.

Antimutagenic effect of eight natural foods on moldy foods in a high liver cancer incidence area

Ames test procedures were used to test 8 natural food extracts for their antimutagenic activity against the mutagenic activity induced in S. typhimurium strains TA98 and TA100 by aflatoxin B1 (AFB1) or metabolic extracts from A. versicolor or A. ochraceus. The tested substances were extracted repeatedly with acetone. The revertants induced by AFB1, metabolic extracts of A. versicolor or A. ochraceus were significantly decreased when extracts of the 8 natural foods were added to the media. The results showed that these extracts had marked inhibitory effects on the mutagenic activity induced by AFB1 or metabolic extracts of the two molds and also suggested that antimutagenic substances were present in these natural foods. These experiments provide a scientific basis for the study of food substances for the prevention of carcinogenesis. It is considered that these 8 natural food extracts produce marked antimutagenic effects and are practically valuable in the field of chemoprophylaxis of liver cancer in humans.

Synthesis and evaluation of radioiodinated 2-(2(RS)-aminopropyl)-5- iodothiophenes as brain imaging agents

Methods have been developed for the preparation of 2-(2(RS)-aminopropyl)-5-iodothiophenes. The syntheses and physical properties of 2-(2(RS)-aminopropyl)-5-iodothiophene and N-isopropyl-2-(2(RS)-aminopropyl)-5-iodothiophene are described. The radioiodinated agents are of interest because of the high expected uptake and prolonged brain retention that may result from binding to high-capacity, relatively nonspecific amine binding sites. Radioiodine was introduced into the 5-position of 2-(2(RS)-aminopropyl)-5-iodothiophene and N-isopropyl-2-(2(RS)-aminopropyl)-5-iodothiophene by radioiodination of the corresponding 5-boronic acid or 5-(trimethylstannyl) derivatives. Tissue distribution studies in rats with 2-(2(RS)-aminopropyl)-5-[125I]iodothiophene showed high brain uptake (5 min, 2.77% dose/g; 30 min, 2.51% dose/g) and good brain/blood (B/B) ratios (5 min, 6/1; 30 min 3.8/1. A comparison of the brain uptake of the N-isopropyl derivative with the 2(RS)-aminopropyl analogue demonstrated higher initial brain uptake and brain to blood ratios (5 min, 3.2% dose/g; 10.3/1) but more rapid washout (30 min, 1.37% dose; 2.8/1). These data suggest that radiolabeled 2-(2(RS)-aminopropyl)-5-iodothiophenes are potentially useful agents for cerebral perfusion imaging by single-photon-emission computerized tomography (SPECT).

Regulatory and antiproliferative effects of N-alkylated polyamine analogues in human and hamster pancreatic adenocarcinoma cell lines

N-Alkylated polyamine analogues have been shown to exert antiproliferative effects in several tumor models, with the bis-ethyl derivatives exerting the greatest suppression of polyamines by virtue of down-regulation of the polyamine biosynthetic enzymes. Pancreatic adenocarcinoma presents a challenge both clinically and experimentally due to its inherent resistance to conventional therapy, which results in its having the worst 5-year survival rate of all cancers. We have previously shown that N1,N12-bis(ethyl)spermine (BESPM) is much more potent than the polyamine enzyme inhibitor alpha-difluoromethylornithine (DFMO) against pancreatic adenocarcinoma cell lines. In the present study, we compared the biochemical and antiproliferative effects of two N-alkylated polyamine analogues, N1,N14-bis(ethyl)homospermine (BEHSPM) and N1,N11-bis(ethyl)norspermine (BENSPM) in two human pancreatic ductal adenocarcinoma cell lines, PANC-1 (poorly differentiated) and BxPC-3 (moderately well-differentiated), and in the WD PaCa (well-differentiated ductal) hamster cell line. BENSPM displayed greater antiproliferative activity in the human pancreatic cancer cell lines, whereas BEHSPM was more potent in the hamster cell line. Both BEHSPM and BENSPM suppress the activity of the major biosynthetic enzymes ornithine decarboxylase and S-adenosylmethionine decarboxylase. However, the induction of polyamine depletion in the human cell lines was only modest for BENSPM and minimal for BEHSPM, which suggests that the substantial antiproliferative activity of these analogues may result from mechanisms other than polyamine depletion. The somewhat greater polyamine depletion seen following treatment with BENSPM is thought to result from its striking induction of spermidine/spermine N1-acetyltransferase. The biochemical and antiproliferative activity of BENSPM makes it an attractive agent for further preclinical and clinical development, especially in pancreatic cancer.

Antitumor effects of N-alkylated polyamine analogues in human pancreatic adenocarcinoma models

Adenocarcinoma of the pancreas presents a formidable challenge both experimentally and clinically, whereby effective anticancer therapy is lacking. We have recently explored a relatively new class of antitumor agents in pancreatic cancer cell lines and have found the bis-ethyl derivatives of spermine to show considerable promise. In the present paper, we report the results of in vivo studies demonstrating the antitumor activity of two of these N-alkylated analogues, N1,N14-bis(ethyl)homospermine (BEHSPM) and N1,N11-bis(ethyl)norspermine (BENSPM) in athymic (nude) mouse xenografts of two human pancreatic ductal adenocarcinoma cell lines, PANC-1 (poorly differentiated) and BxPC-3 (moderately well-differentiated). BENSPM was found to exert greater antitumor activity in vivo than either BEHSPM or other conventional agents, largely because higher doses could be given due to its lower toxicity to mice. BENSPM shows greater activity than any other agent we have thus far tested against our pancreatic-cancer models. Optimal schedules of administration have yet to be determined. Nevertheless, of the analogues tested, BENSPM presently appears to be the analogue of choice for further development.

Effects of fat on insulin-stimulated carbohydrate metabolism in normal men

We have examined the onset and duration of the inhibitory effect of an intravenous infusion of lipid/heparin on total body carbohydrate and fat oxidation (by indirect calorimetry) and on glucose disappearance (with 6,6 D2-glucose and gas chromatography-mass spectrometry) in healthy men during euglycemic hyperinsulinemia. Glycogen synthase activity and concentrations of acetyl-CoA, free CoA-SH, citrate, and glucose-6-phosphate were measured in muscle biopsies obtained before and after insulin/lipid and insulin/saline infusions. Lipid increased insulin-inhibited fat oxidation (+40%) and decreased insulin-stimulated carbohydrate oxidation (-63%) within 1 h. These changes were associated with an increase (+489%) in the muscle acetyl-CoA/free CoA-SH ratio. Glucose disappearance did not decrease until 2-4 h later (-55%). This decrease was associated with a decrease in muscle glycogen synthase fractional velocity (-82%). The muscle content of citrate and glucose-6-phosphate did not change. We concluded that, during hyperinsulinemia, lipid promptly replaced carbohydrate as fuel for oxidation in muscle and hours later inhibited glucose uptake, presumably by interfering with muscle glycogen formation.

[A Chinese family with high prevalence of leukemia]

A family with high prevalence of leukemia in Fujian, China was investigated and followed-up for 10 years. 7 members of the family had leukemia. Chromosome analyses once had found that three normal members in the family had chromosome abnormalities, and leukemia occurred in two of them 5 and 7 years later respectively. Family tree analysis showed that hereditary defects are in the maternal side. The author believes that hereditary defects play an important role in familial leukemia.

Effects of alternate RNA splicing on glucokinase isoform activities in the pancreatic islet, liver, and pituitary

Different glucokinase isoforms are produced by tissue-specific alternative RNA splicing in the liver and pancreatic islet, the only tissues in which glucokinase activity has been detected. To determine whether differences in protein structure brought about by alternative RNA splicing have an effect on glucose phosphorylating activity, we expressed cDNAs encoding four different hepatic and islet glucokinase isoforms and determined the Km and Vmax of each. When the glucokinase B1 and L1 isoforms were expressed in eukaryotic cells, both high Km glucose phosphorylating activity and immunoreactive protein were detected. However, when the glucokinase B2 and L2 isoforms were expressed, both of which differ by deletion of 17 amino acids in a region between the putative glucose and ATP-binding domains, no high Km glucose phosphorylating activity and much less immunoreactive protein were detected. When the glucokinase B1 and B2 isoforms were expressed in Escherichia coli as fusion proteins with glutathione S-transferase, affinity-purified B1 fusion protein was able to phosphorylate glucose whereas the B2 fusion protein was not, thus indicating that the lack of glucose phosphorylating activity from both the B2 and L2 isoforms is due to lack of intrinsic activity in addition to accumulation of less protein. The Km values of the B1 and L1 isoforms, which differ from each other by 15 amino acids at the NH2 terminus, were similar, but the Vmax of the B1 isoform was 2.8-fold higher than that of the L1 isoform. Mutagenesis of the first two potential initiation codons in the glucokinase B1 cDNA from ATG to GTC (methionine to valine) indicated that the first ATG was crucial for activity and is, therefore, the likely translation initiation codon. Messenger RNAs encoding both the B2 and L2 isoforms of glucokinase were detected in islet and liver by polymerase chain reaction amplification of total cDNA, indicating that mRNAs utilizing this weak alternate splice acceptor site in the fourth exon are normally present in both the liver and islet but as minor components. A regulatory role for weak alternate splice acceptor and donor sites in the glucokinase gene was suggested by examining the expression of the gene in the pituitary and in AtT-20 cells. Interestingly, although glucokinase mRNAs of appropriate sizes were detected in both the AtT-20 cells and rat pituitaries, neither exhibited any detectable high Km glucose phosphorylating activity.(ABSTRACT TRUNCATED AT 400 WORDS)

Content of CoA-esters in perifused rat islets stimulated by glucose and other fuels

Fluorometry and high-performance liquid chromatography were used to measure the content of free CoA and the esters of acetate, malonate, succinate, and long-chain fatty acids in isolated perifused rat pancreatic islets exposed to 25 mM glucose or a mixture of fuels (25 mM glucose plus 10 mM glutamine, 10 mM lactate, and 1 mM pyruvate) to assess the role of intermediates of lipid metabolism as candidate metabolic coupling factors in the mechanism of fuel-induced insulin secretion. Insulin secretion was stimulated in a biphasic manner with the fuel mixture, showing twice the potency compared with high glucose alone. Islets perifused for 3 min with high glucose alone or the fuel mixture compared with 2.5 mM glucose showed a significant increase in malonyl-CoA and succinyl-CoA and a decrease in acetyl-CoA. Free CoA and long-chain acyl-CoA levels were unaltered. Perifused islets stimulated with 25 mM glucose for 30 min showed a significant increase in succinyl-CoA and long-chain acyl-CoA and decrease in acetyl-CoA, whereas malonyl-CoA was not affected. However, when islets were stimulated by the fuel mixture for 30 min, malonyl-CoA was maintained at a high level, and the change in succinyl-CoA and long-chain acyl-CoA was similar to that observed in islets stimulated with 25 mM glucose alone. The acetyl-CoA concentration in the islets stimulated with the fuel mixture decreased slightly. These results confirm the viability of the hypothesis that malonyl-CoA and long-chain acyl-CoA serve as metabolic coupling factors in signal transduction when islets are stimulated by high glucose or glucose combined with other fuels.

[Cerebellar infarction and its assistant examination]

The clinical manifestations of cerebellar infarction are often non-particular and it is difficult to make such a diagnosis clinically. Diagnosis was based on pathology previously. Most of the cases were overlooked while still living and the true morbidity was not known. CT scan has made the diagnosis of this disease possible clinically in some patients, but CT is still not an ideal instrument for diagnosing this disease because of the interference by bony artifacts of posterior fossa. The advent of MRI made it possible to distinguish cerebellar infarction safely and easily. It is not the most powerful tool for diagnosing this disease. The authors reported 15 cases of cerebellar infarction diagnosed by clinical manifestation, neuroimages and pathology and pointed out that further knowledge of this disease is needed.

[Immunohistochemical study of extracellular matrices in human glioma and meningioma]

The expression and distribution of the extracellular matrix (ECM) in 37 gliomas and 19 meningiomas were studied immunohistochemically by antibodies to type 3, 4 and 6 collagen, fibronectin and laminin. In gliomas the expression of these antigens was more intense and thicker in the tumor vessel walls, and was positively correlated to the malignant degree of the gliomas. This suggests that the thickening of the vessel walls and the increase of their ECM components in gliomas may be one of the causes why gliomas are extremely rare to metastasize to the outside of the cranium. All the above-cited ECM were positive in the fibroblastic type of meningioma, being just located between the tumor cells; whereas in syncytial type they were negative. This indicates that the immunohistochemistry of ECM may be of advantage in differentiating meningioma type.

Glucose regulates glucokinase activity in cultured islets from rat pancreas

In this study, we have used isolated pancreatic islets cultured for 7 days in 3 or 30 mM glucose to explore whether glucokinase is induced or activated by high glucose concentrations and has related enzyme activity to glucose-stimulated insulin release. Islets cultured in low glucose medium or low glucose medium plus 350 ng/ml insulin did not respond to high glucose stimulation. Islets cultured in medium containing high glucose concentrations showed a high rate of basal insulin secretion when perifused with 5 mM glucose, and the insulin release was greatly augmented in a biphasic secretion profile when the glucose concentration was raised to 16 mM. Islet glucokinase and hexokinase activities were determined by a sensitive and specific fluorometric method. Glucokinase activity was reduced to approximately 50% in islets cultured in low glucose medium with or without insulin present compared to results with fresh islets. However, islets cultured in 30 mM glucose showed that glucokinase activity was elevated to 236% compared to results with fresh islets. It is concluded that (a) glucose is the physiological regulator of glucokinase in the islet of Langerhans and that (b) the activity of glucokinase plays a crucial role in glucose-induced insulin secretion.