In vivo actions of insulin-like growth factor-I (IGF-I) on cerebellum development in transgenic mice: evidence that IGF-I increases proliferation of granule cell progenitors

The in vivo actions of insulin-like growth factor-I (IGF-I) on cerebellum development have been investigated in transgenic (Tg) mice (IGF-II/I Tg mice) in whom an IGF-II promoter-driven IGF-I transgene is highly expressed in cerebellum. Compared to normal littermates, the brains of IGF-II/I Tg mice exhibited overgrowth beginning from the second week of postnatal life. Among the brain regions examined, cerebellum exhibited the greatest increase in size, such that by 50 days of age cerebellar weight and DNA content were increased by 90% and 143%, respectively, compared to littermate controls. Morphological studies of adult IGF-II/I Tg mice showed that the total number of granule and Purkinje cells was increased by 82% and 20%, respectively, findings consistent with the increased cerebellar DNA content and indicating that the increased cerebellar weight was due in part to an increase in cell number. The thickness of the molecular layer also was increased in IGF-II/I Tg mice. During early postnatal development the number of external granular layer cells, as well as the number of BrdU labeled external granular cells, was increased. These data strongly indicate that IGF-I increases granule cell number by a mechanism that involves the stimulation of granule cell progenitor proliferation. Our findings also indicate that IGF-I influences the growth of Purkinje cells and possibly of other cell types in the cerebellum.

Picosecond optical bistability in metallophthalocyanine-doped polymer film waveguides

Ultrafast optical bistability was observed in a planar optical waveguide made with a 2,9,16,23-tetraoctadecanoylamido-substituted vanadyl phthalocyanine-doped polystyrene film. Input-output curves with hysteresis characteristics were measured with laser pulses of 60-ps pulse width at 532 nm. The switchup and switchdown times were less than 10 and 20 ps, respectively. The origin of the nonlinearity giving rise to optical bistability was predominantly electronic effects.

Use of transgenic mice for understanding the physiology of insulin-like growth factors

Manipulation of the murine genome, either by the insertion of transgenes or by disruption of native genes (so-called gene knockout, accomplished by homologous recombination), and study of the resultant mutant mice have proved invaluable to our understanding of insulin-like growth factor (IGF) physiology. Such investigations have demonstrated that expression of both IGF-I and IGF-II is essential to normal in utero growth of the fetus, while IGF-II is required for normal placental growth. IGF-I is necessary for normal in utero maturation and postnatal growth. Data from study of type 1 IGF receptor (IGF 1R) knockout mice indicate that this receptor mediates most IGF-I and IGF-II growth-promoting actions. The central importance of the IGFs and the IGF 1R to development is underscored by the fact that IGF 1R knockout mice do not survive past birth. Our more recent studies of transgenic mice have begun to demonstrate IGF-I actions in brain, such as the stimulation of myelination and the augmentation of neurone survival.

Insulin-like growth factor-I influences the initiation of myelination: studies of the anterior commissure of transgenic mice

The effects of insulin-like growth factor-I (IGF-I) on the initiation of myelination have been examined in the posterior portion of anterior commissure of the transgenic (Tg) mice that overexpress IGF-I in brain, and those which exhibit ectopic brain expression of IGF binding protein-1 (IGFBP-1), an inhibitor of IGF actions. In IGF-I Tg mice the number of ensheathed axons was increased compared to their normal littermates. The distribution of the axon size further showed that both small (< 300 nm) and large (> 700 nm) axons were more often ensheathed and myelinated. The opposite was true in IGFBP-1 Tg mice. These data indicate that IGF-I increases myelin ensheathment independent of axon diameter, and support the hypothesis that the absolute axon size is not the sole determinant for the initiation of myelination in CNS.

In vivo actions of insulin-like growth factor-I (IGF-I) on brain myelination: studies of IGF-I and IGF binding protein-1 (IGFBP-1) transgenic mice

To study the effects and mechanisms of insulin-like growth factor I (IGF-I) on brain myelination in vivo, the morphology of myelinated axons and the expression of myelin specific protein genes have been examined in transgenic (Tg) mice that overexpress IGF-I and that those ectopically express IGF binding protein-1 (IGFBP-1), a protein that inhibits IGF-I actions when present in molar excess. Our data show that the percentage of myelinated axons and the thickness of myelin sheaths are significantly increased in IGF-I Tg and decreased in the IGFBP-1 mice. Cerebral cortical proteolipid protein (PLP) and myelin basic protein (MBP) mRNAs consistently exhibit approximately 200% increases in IGF-I Tg mice and approximately 50% decreases in IGFBP-1 Tg mice. The percentage of oligodendrocytes labeled with a PLP cRNA probe in the corpus callosum and cerebral cortex also is increased in IGF-I Tg mice and reduced in IGFBP-1 Tg mice, suggesting that IGF-I promotes oligodendrocyte survival and/or proliferation. The alterations in the number of oligodendrocytes, however, can not completely account for the changes in myelin gene expression. These results strongly indicate that IGF-I increases myelination by increasing the number of myelinated axons and the thickness of myelin sheaths, the latter by mechanisms that involve stimulation of the expression of myelin protein genes and increase of oligodendrocyte number.

All-optical bistability in doped-polymer film waveguides

All-optical bistability was observed in thin-film waveguides made with acceptor-donor substituted azobenzene-doped poly(methyl methacrylate) polymer. Input-output curves with hysteresis characteristics were measured. The origin of the bistability was attributed to nonlinear coupling between a prism and a doped-polymer waveguide. An approximately theoretical analysis was introduced. Theoretical predictions were qualitatively consistent with experimental results.

Light-induced noncentrosymmetry in acceptor-donor-substituted azobenzene solutions

Light-induced noncentrosymmetry was achieved experimentally in acceptor-donor-substituted azobenzene solutions and observed by phase-matched nondegenerate six-wave mixing. The microscopic origin of the induced noncentrosymmetry was found to be orientational hole burning, which was distinguished directly with net orientation of molecules by experimental observations. The decay time of the induced noncentrosymmetry depended on the rotational orientation time of the sample's molecule, which varied linearly with the viscosity of the solvent.

Association of polymorphisms of the apolipoprotein B gene with coronary heart disease in Han Chinese

Four polymorphic sites of the apolipoprotein B (apo B) gene were investigated by using polymerase chain reaction (PCR) in 103 patients with coronary heart disease (CHD) and 100 age-matched healthy individuals selected from a population of Han Chinese in the Beijing area. The rare X+ allele of the XbaI restriction site was more frequently seen in CHD patients than in controls (0.088 vs. 0.025, P < 0.01). The relative frequency of rare E- allele of the EcoRI restriction site was significantly higher in CHD patients compared with controls (0.11 vs. 0.04, P < 0.01). Similarly, 3'VNTR-L allele (number of repeat units > 39) at the VNTR region was also present at an apparently high frequency in CHD patients in comparison to that in controls (0.602 vs. 0.290, P < 0.001). However, the difference in relative frequency of rare Del allele of the Ins/Del polymorphism at the signal peptide was not significant between the two groups (0.282 vs. 0.235. P > 0.05). In comparison with Caucasians, the relative frequencies of rare alleles (Del, X+ and E-) were found to be statistically lower in Han Chinese. Furthermore, the Del and X+ alleles, in linkage disequilibrium, were associated with significantly lower plasma level of HDL-C in CHD patients. Therefore it is suggested that genetic variation with the apo B gene may exert some impact on lipid metabolism and contribute to the susceptibility to development of CHD in Han Chinese.

Vaccination of sheep against Schistosoma japonicum with either glutathione S-transferase, keyhole limpet haemocyanin or the freeze/thaw schistosomula/BCG vaccine

The protective potential of glutathione S-transferase (GST), keyhole limpet haemocyanin (KLH) and the freeze/thaw (F/T) schistosomula/BCG vaccine was evaluated against Schistosoma japonicum in the natural sheep host. Groups of ten sheep each were vaccinated as follows: Group I: 2 x F/T 30,000 schistosomula+BCG 3 x 10(8) organisms, with a 2 week interval between vaccinations (F/T 'Low'). Group II: 3 x F/T 20,000 schistosomula+BCG 3 x 10(8), with 4 week interval (F/T 'High'). Group III: 2 x GST 0.24 mg+FCA (Freund's complete adjuvant) with 2 week interval (GST 'Low'). Group IV: 3 x GST 0.24 mg+FCA, with 4 week interval (GST 'High'). Group V: 2 x KLH 1.0 mg in phosphate-buffered saline (PBS), with 2 week interval (KLH 'Low'). Group VI: 3 x KLH 1.0 mg in PBS, with 4 week interval (KLH 'High'). Group VII: control (not vaccinated). Specific antibody, detected by GST-enzyme-linked immunosorbent assay (ELISA) and KLH-ELISA on the day after the last vaccination and 1, 2 and 3 weeks post-challenge, was found in all GST- or KLH-vaccinated groups. The same was found in F/T schistosomula-vaccinated groups against crude adult worm antigen (AWA). In Western blotting all GST-vaccinated sera recognized 26 kDa and 28 kDa bands on the challenge day and at 3 and 11 weeks post-challenge. Mean faecal egg counts between Weeks 6 and 10 post-challenge were reduced in a statistically significant way at five time points in the four groups, i.e. 83.38% (P < 0.005) in Group II, 49.29% (P < 0.025) in Group III, 47.9% (P < 0.05) and 71.15% (P < 0.01) in Group IV, 52.0% (P < 0.025) and 66.38% (P < 0.025) in Group VI. On autopsy and perfusion 1 week after the last faecal count, adult worm reductions were obtained of 40.36% (P < 0.05) in Group I, 37.26% (P < 0.025) in Group II, 24.73% (not significant) in Group III, 35.93% (P < 0.025) in Group IV, 27.46% (P < 0.05) in Group V and 33.81% (P < 0.01) in Group VI. Mean tissue egg densities were also reduced significantly in Groups III, IV and VI, especially in Group IV vaccinated animals. Mean liver egg granuloma diameters of the vaccinated groups were found to be less than those of the controls but there was no statistical significance.(ABSTRACT TRUNCATED AT 400 WORDS)

Frequent detection of bcl-2/JH translocations in human blood and organ samples by a quantitative polymerase chain reaction assay

Using an ultrasensitive assay involving the PCR, we have examined the frequency of a follicular lymphoma-associated translocation in peripheral blood from 132 individuals, most of whom were healthy blood donors. This translocation occurs between the bcl-2 proto-oncogene and the JH gene region and prolongs the life of lymphocytes. At a level of sensitivity of 1 translocation-bearing cell per 5 x 10(6) cells, almost one-half of healthy human adults had this translocation in the mononuclear fraction of peripheral blood. However, the range of frequency of these translocations spanned almost three orders of magnitude among translocation-positive individuals. Furthermore, there was a statistically significant increase with age in the percentage of individuals who were translocation positive. Such an age correlation was also seen for the percentage of blood donors with rather high translocation frequencies (> or = 20 per 5 x 10(6) peripheral blood mononuclear cells). However, the blood donor who had by far the highest concentration of this translocation was a healthy 35-year-old male containing approximately 900 apparently monoclonal, translocation-bearing cells per 5 x 10(6) peripheral blood mononuclear cells. Our findings suggest that some individuals who may be at risk for follicular lymphoma might be able to be identified by this PCR assay on peripheral blood. Also, these data may help explain the age dependence of the occurrence of this cancer.

The association of polymorphisms at a VNTR locus 3' to the apolipoprotein B gene with coronary heart disease in Chinese population

The polymorphisms of variable number of tandem repeats (VNTR) 3' to the apolipoprotein B (apo B) gene were investigated using polymerase chain reaction (PCR) in a sample of 103 patients with documented coronary heart disease (CHD) and 100 healthy individuals selected from Chinese Han nationality. Twelve segregating alleles (3' beta 29-51) were observed in the pooled total of 203 subjects. The most common allele was 3' beta 37, followed by 3' beta 39 with frequencies of 0.362 and 0.296, respectively. This model of allele distribution was coincident with the results form different ethnic groups, but the relative frequencies of alleles were different. In comparison with the allele frequencies between the patients and controls, alleles bigger than 3' beta 39 (3' VNTR-B) were significantly more common among the patients than among the controls (P < 0.001). Moreover, in the CHD group patients with plasma levels of TC > or = 3.88 mmol/L, LDL-C > or = 2.59 mmol/L and HDL-C < 1.16 mmol/L had significantly higher frequencies of 3' VNTR-B allele (P < 0.01). Therefore, it is suggested that 3' VNTR-B allele might be involved in the development of coronary atherosclerosis, presumably through their influences on lipid metabolism.

Self-pumped phase-conjugation properties of cerium-doped BaTiO(3) crystals in the near infrared

Studies of a new Ce-doped BaTiO(3) crystal as an efficient self-pumped phase conjugator in the near infrared are presented. The internal beam production during the establishment of self-pumped phase conjugation (SPPC) is closely observed, and the corresponding mechanisms of SPPC are identified accordingly. When the incident beam is in an a-face-incidence geometric arrangement, it is observed for the first time that SPPC mechanism has a transition from stimulated photorefractive backscattering and four-wave mixing to total internal reflection when λ is varied from 706 to 733 nm. Variations of the SPPC reflectivity with the λ, incident angle, and position of the input beam have been investigated, and a high reflectivity of approximately 80% has been obtained. In addition, SPPC reflectivity of approximately 40% is obtained when the incident beam enters the crystal by the +c face, and a variation with λ of optical beam patterns in the crystal has also been observed. Qualitative explanations of the phenomenon of SPP mechanism transition with λ that will be very useful in practical applications are given.

Human insulin-like growth factor binding protein-1 (hIGFBP-1) transgenic mice: insights into hIGFBP-1 regulation and actions

Three hemizygous transgenic (Tg) mouse lines were generated with a fusion gene composed of the mouse metallothionein promoter (mMT-1) and a full length human insulin-like growth factor binding protein-1 (hIGFBP-1) cDNA that was truncated in its 3' untranslated (3'UT) region. The transgene was ectopically expressed in the brain of each line and resulted in postnatal brain-growth retardation that was manifested by 2 weeks of age. Despite the expression of the transgene in multiple other tissues and high serum hIGFBP-1 concentrations in two of the three lines, studies designed to detect alterations in somatic growth, in reproduction and in glucose metabolism revealed few other abnormalities. Unexpectedly, however, we found that the regulation of the transgene shared characteristics with that of the native gene, despite the fact that it lacked the endogenous gene's 5' regulatory region, as well as most of its 3' UT region. Our studies suggest that factors controlling mRNA stability are important to regulation of both the native and transgene, and that an AU-rich element 17 base pairs (bp) from the end of coding sequence is responsible for the instability of the transgene and in part for instability of the endogenous gene.

[Apolipoprotein B signal peptide insertion/deletion polymorphism in Chinese patients with coronary heart disease]

Insertion/deletion (Ins/Del) polymorphism of the apo B gene encoding signal peptide and its relation to coronary heart disease (CHD) and lipid trait were studied in 103 patients with CHD and 100 healthy individuals from Chinese Han nationality. The frequency of rare Del allele was 0.259, which was significantly lower than 0.34 in Caucasians (France), but higher than 0.16 in South Asian descents in UK. When the frequency distribution of the Ins/Del alleles was compared between CHD group and control group, the frequency of rare Del allele in the patient group was not apparently different from that in the control group (0.282 vs. 0.235, P > 0.05). As for the impact of the Ins/Del genotype on levels of lipid and apolipoprotein, the patients with at least one Del allele had significantly lower HDL-C level compared with those with only Ins allele in the CHD group (P < 0.01). Levels of other lipid parameters in each group were not obviously associated with the Ins/Del genotype. It is suggested that the Ins/Del polymorphism of the apo B signal peptide might be involved in lipid metabolism by an unidentified mechanism in some ethnic population. PCR is a useful method for distinguishing Ins/Del polymorphism of the apo B signal peptide.

Mechanism transformation with wavelength of self-pumped phase conjugation in BaTiO(3):Ce

We report what is to our knowledge the first observation of mechanism transformation with wavelength of self-pumped phase conjugation (SPPC) in BaTiO(3):Ce crystals in the near infrared. It was found that the SPPC mechanism changed from a backscattering and four-wave-mixing mechanism to a cat mechanism when the pump wavelength was varied from 706 to 770 nm. In addition, SPPC was obtained when the pump beam entered the crystal by the +c face, and a variation with wavelength of optical beam paths in the crystal was also observed.

Transcriptional regulation of myelin associated glycoprotein gene expression by cyclic AMP

The treatment of rat glioma C6 cells with 10 microM isoproterenol (Ipt) for 4 days upregulated the expression of the myelin-associated glycoprotein (MAG) gene by approximately 55-fold over the control value. The constant presence of Ipt in the medium was required for the maximal upregulation, as time-restricted exposures to the drug produced only partial, or no upregulation of the gene. No difference in the MAG mRNA stability could be detected in Ipt-treated vs untreated cells indicating that the drug upregulates the MAG gene at transcriptional level. Serum (FCS) strongly attenuated the response of the MAG gene to Ipt. The stimulatory effect of Ipt was profoundly reduced by spermine and H-89, indicating that protein kinase A-dependent protein phosphorylation is involved in the MAG gene activation. Within 30 min after Ipt administration, the c-fos gene was upregulated by 10-fold, and thereafter, its message level decreased and stabilized at approximately 3-fold over control. In contrast, the c-jun gene was downregulated to approximately 20% of control within 30 min after Ipt administration. Subsequently, its message level rose and fell once again within 12 h to approximately half of control, and returned to control level within 72 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Polymorphisms of apolipoprotein B gene in relation to coronary heart disease in Chinese Han nationality

Two polymorphic sites of apolipoprotein B (apoB) gene, XbaI and EcoRI, were examined in 80 patients with documented coronary heart disease (CHD) and 60 healthy individuals selected from a population of Chinese Han nationality. Allele frequencies at these sites were compared between the patients and controls and their impact on lipid metabolism was also investigated. The frequency of X+ allele (presence of XbaI cutting site) in CHD patients was 0.10, which was significantly higher than 0.01 in controls (P < 0.001). The same trend was detected for frequency of E-allele (lack of EcoRI cutting site) when it was compared between CHD patients and controls (0.11 vs 0.05), the difference was not statistically significant (P < 0.1, > 0.05). There was no relationship between XbaI RFLP and EcoRI RFLP. In the CHD patients, X+ allele was associated with the lower levels of HDL-C and apoAI when compared with X- allele, while no associations were found of X+ allele with other lipid parameters. On the contrary, the EcoRI polymorphism had no significant influence on plasma lipid and lipoprotein levels. Therefore, it was suggested that genetic variation at XbaI site of apoB gene might contribute to the determination of plasma HDL-C level and development of CHD in people among Chinese Han nationality.

Low-power and broadband optical bistability by excitation of surface plasmons in doped polymer film

The low-power and broadband optical bistability in an acceptor-donor-substituted azobenzene-doped polymethyl methacrylate thin film, which relies on the excitation of surface plasmons with a cw laser of several tens of milliwatt power, is studied experimentally and theoretically. The observations on the characteristics of the bistability are essentially consistent with the theoretical predictions.

Spectral measurements of NH(3) absorption lines by a 1.5-microm grating-external-cavity semiconductor laser

Forty-four NH(3) absorption spectral lines of the combination tones of the vibration-rotation transitions were observed at 1.4988-1.5520 microm with a 1.5-microm grating-external-cavity semiconductor laser. The linewidth and absorption rate of NH(3) absorption spectral lines were measured. Also, the changes of center frequency and linewidth of the NH(3) absorption spectral line with the our knowledge the first time.

Vaccination of bovines against Schistosomiasis japonica with cryopreserved-irradiated and freeze-thaw schistosomula

Four laboratory tests and one field trial with cryopreserved irradiated (CI) schistosomula vaccine and a freeze-thaw (F/T) vaccine against bovine Schistosomiasis japonica were carried out in 1979 and 1980 with the following results: (1) Single intradermal vaccination in buffalo calves each with 10,000 20 krad CI Schistosomula plus 1 ml BCG gave 62% worm reduction (P < 0.05). Using the same protocol 55% worm reduction (P < 0.01) was obtained in cattle. (2) Buffalo calves immunized twice, at a 1.5 month interval, with 10,000 and 20,000 CI schistosomula, respectively, resulted in a worm reduction 65%. (3) In a preliminary field trial with 10,000 CI schistosomula plus 1 ml BCG resulted in a worm reduction of 53% in buffalo calves. (4) Intradermal vaccination of 30,000 F/T schistosomula with 1 ml BCG was also tried in cattle and revealed a worm reduction of 57% but increasing the number of vaccinations did not improve the protective effect. (5) Evidence regarding the effects of immunization with CI vaccine in buffaloes and F/T vaccine in cattle, on the number of eggs and miracidia and that of female worms themselves was obtained. (6) Immune responses, cellular and humoral, elicited in buffaloes vaccinated with CI schistosomula were detected by means of Lymphocyte Transformation Assay and Enzyme Linked Immunosorbent Assay.