Sensitive method for measuring third order nonlinearities in compact dielectric and hybrid plasmonic waveguides

We demonstrate a sensitive method for the nonlinear optical characterization of micrometer long waveguides, and apply it to typical silicon-on-insulator nanowires and to hybrid plasmonic waveguides. We demonstrate that our method can detect extremely small nonlinear phase shifts, as low as 7.5·10<(-4) rad. The high sensitivity achieved imparts an advantage when investigating the nonlinear behavior of metallic structures as their short propagation distances complicates the task for conventional methods. Our results constitute the first experimental observation of χ((3)) nonlinearities in the hybrid plasmonic platform and is important to test claims of hybrid plasmonic structures as candidates for efficient nonlinear optical devices.

Absence of a FOXL2 mutation (402C→G) in the blood of adult-type granulosa cell tumor patients possessing the FOXL2 mutation

Recently, a new mutation in FOXL2, c.402C→G leading to a p.C134W change, was reported to be found in 97% of adult-type ovarian granulosa cell tumors (GCTs) tested. In the current study, we compared the FOXL2 sequences of genomic DNA isolated from both GCT and blood. Although the GCTs of patients possessed the FOXL2 mutation, their FOXL2 nucleotide sequences of genomic DNA isolated from matching blood samples lacked the 402C→G mutation. Therefore, we confirmed that the nucleotide alteration of FOXL2 is due to a somatic mutation and demonstrated that sequencing of blood DNA for the detection of the FOXL2 mutation is not a useful method for the diagnosis of GCT.

Age-dependent fatigue behaviour of human cortical bone

Despite a general understanding that bone quality contributes to skeletal fragility, very little information exits on the age-dependent fatigue behavior of human bone. In this study four-point bending fatigue tests were conducted on aging bone in conjunction with the analysis of stiffness loss and preliminary investigation of nanoindentation based measurements of local tissue stiffness and histological evaluation of resultant tensile and compressive damage to identify the damage mechanism responsible for the increase in age-related bone fragility. The results obtained show that there is an exponential decrease in fatigue life with age, and old bone exhibits different modulus degradation profiles than young bone. In addition, this study provides preliminary evidence indicating that during fatigue loading, younger bone formed diffuse damage, lost local tissue stiffness on the tensile side. Older bone, in contrast, formed linear microcracks lost local tissue stiffness on the compressive side. Thus, the propensity of aging human bone to form more linear microcracks than diffuse damage may be a significant contributor to bone quality, and age related fragility in bone.

156INFLUENCE OF SERUM AND BSA ON BLASTOCYST DEVELOPMENT AND HATCHING IN IVF AND NUCLEAR TRANSFER BOVINE EMBRYOS

Important differences exist between in vivo- and in vitro-produced bovine embryos. Studies have shown that various components in culture media affect embryo development, with serum producing some of the more detrimental effects. Efforts to develop a serum-free culture system have included looking at the effects of BSA, polyvinyl pyrrolidone and polyvinyl alcohol on embryo development. In this study, we compare serum and BSA during oocyte maturation and embryo culture of IVF and nuclear transfer (NT) embryos. Experiment A: Oocytes were aspirated from follicles and matured in either collection medium (Hams F-10+2% steer serum (SS); F-10) or in follicular fluid alone (FF). They were subjected to IVM-IVF-IVC as follows: 20–22h maturation in synthetic oviductal fluid +8mgmL−1 fatty acid-free BSA (SOF+BSA-FAF) supplemented with hormones, 18h co-incubation with sperm in IVF-TALP, and culture for 9 days in SOF+BSA-FAF. Experiment B: Oocytes were randomly distributed for IVM-IVF-IVC into the following treatment groups: (i) IVM and IVC in SOF+2% SS (SER), (ii) IVM in SOF+2% SS and IVC in SOF+BSA-FAF (SER-FAF), (iii) IVM and IVC in SOF+BSA-FAF (FAF), and (iv) IVM and IVC in SOF+BSA-FrV (FrV). Experiment C: Oocytes were matured for 18h in either SOF+2% SS (SER) or SOF+BSA-FAF (FAF). Couplets were constructed with adult skin fibroblasts, exposed to a single pulse of 1.5kVcm−1 for 40s and activated using ionomycin and cycloheximide. Embryos were cultured in SOF+BSA-FAF. Three replicates with 100–120 oocytes per treatment group were carried out. Results: Cleavage rates were similar among all treatments in experiments A and B. No differences were observed between oocytes collected in F-10 or FF indicating that short-term exposure to serum does not have long-term effects on embryo development. Although a higher number of blastocysts was observed in the SER group on Day 6 (3.2% v. &lt;0.5%; P&lt;0.05), no differences were seen in blastocyst development among the IVF treatment groups from Day 8 onwards (SER: 29.7%, SER-FAF: 21.1%, FAF: 20.4%, FrV: 19.9%). However, hatching rates on Days 8 and 9 were significantly greater (P&lt;0.05) in groups with serum, with the exception of FAF on Day 9 (SER: 31.1%, 57.2%; SER-FAF: 29.4%, 50.6%; FAF: 23.1%, 46.4%; FrV: 18.5%, 34.2%). In the NT treatment groups, the presence of serum during IVM resulted in a higher proportion of MII oocytes at 18h, better oocyte quality for manipulation, and increased blastocyst development and hatching rates (SER: 31.4%, 18.2%; FAF: 21.7%, 4.8%). These results indicate that both serum and fatty acid-free BSA provide comparable embryo development during IVF. However, development in serum occurs at an accelerated rate as indicated by the shorter nuclear maturation times and blastocyst development on Day 6, which has been associated with adverse outcomes. Despite this, serum may provide the oocyte with factors that are important for membrane flexibility and repair, enabling greater survival after manipulation. Funding from NSERC and OMAFRA. Sperm provided by Gencor.

La autoantigen enhances translation of BiP mRNA

Translational initiation of the human BiP mRNA is directed by an internal ribosomal entry site (IRES) located in the 5'-untranslated region (5'-UTR). In order to understand the mechanism of the IRES-dependent translation of BiP mRNA, cellular proteins interacting with the BiP IRES were investigated. La autoantigen, which augments the translation of polioviral mRNA and hepatitis C viral mRNA, bound specifically to the second half of the 5'-UTR of the BiP IRES and enhanced translation of BiP mRNA in both in vitro and in vivo assays. This finding suggests that cellular and viral IRESs containing very different RNA sequences may share a common mechanism of translation.

TDAG51 is not essential for Fas/CD95 regulation and apoptosis in vivo

Fas/CD95 is a key regulator of apoptotic signaling, which is crucial for the maintenance of homeostasis in peripheral lymphoid organs. TDAG51 has been shown to play critical roles in the up-regulation of Fas gene expression and T-cell apoptosis in vitro. In order to identify the role of TDAG51 in vivo, we generated TDAG51-deficient (TDAG51-/-) mice. Northern blotting revealed no expression of TDAG51 in TDAG51-/- mice, indicating that the TDAG51 gene was successfully targeted. TDAG51-/- mice were healthy and showed no gross developmental abnormalities. While Fas-deficient mice display marked lymphadenopathy, splenomegaly, and lymphocytosis, TDAG51-/- mice had no apparent defects in secondary lymphoid organs. Although TDAG51 is required for up-regulation of Fas expression in T-cell hybridomas, TDAG51-/- mice expressed normal levels of Fas and had normal T-cell apoptosis. Therefore, we conclude that TDAG51 is not essential for Fas up-regulation and T-cell apoptosis in vivo. There are several known homologs of TDAG51, and these homologs may substitute for TDAG51 in TDAG51-/- mice.

The arginine-1493 residue in QRRGRTGR1493G motif IV of the hepatitis C virus NS3 helicase domain is essential for NS3 protein methylation by the protein arginine methyltransferase 1

The NS3 protein of hepatitis C virus (HCV) contains protease and RNA helicase activities, both of which are likely to be essential for HCV propagation. An arginine residue present in the arginine-glycine (RG)-rich region of many RNA-binding proteins is posttranslationally methylated by protein arginine methyltransferases (PRMTs). Amino acid sequence analysis revealed that the NS3 protein contains seven RG motifs, including two potential RG motifs in the 1486-QRRGRTGRG-1494 motif IV of the RNA helicase domain, in which arginines are potentially methylated by PRMTs. Indeed, we found that the full-length NS3 protein is arginine methylated in vivo. The full-length NS3 protein and the NS3 RNA helicase domain were methylated by a crude human cell extract. The purified PRMT1 methylated the full-length NS3 and the RNA helicase domain, but not the NS3 protease domain. The NS3 helicase bound specifically and comigrated with PRMT1 in vitro. Mutational analyses indicate that the Arg(1493) in the QRR(1488)GRTGR(1493)G region of the NS3 RNA helicase is essential for NS3 protein methylation and that Arg(1488) is likely methylated. NS3 protein methylation by the PRMT1 was decreased in the presence of homoribopolymers, suggesting that the arginine-rich motif IV is involved in RNA binding. The results suggest that an arginine residue(s) in QRXGRXGR motif IV conserved in the virus-encoded RNA helicases can be posttranslationally methylated by the PRMT1.

Prmt5, which forms distinct homo-oligomers, is a member of the protein-arginine methyltransferase family

We found that JBP1, known as a human homolog (Skb1Hs) of Skb1 of fission yeast, interacts with NS3 of the hepatitis C virus in a yeast two-hybrid screen. Amino acid sequence analysis revealed that Skb1Hs/JBP1 contains conserved motifs of S-adenosyl-l-methionine-dependent protein-arginine methyltransferases (PRMTs). Here, we demonstrate that Skb1Hs/JBP1, named PRMT5, is a distinct member of the PRMT family. Recombinant PRMT5 protein purified from human cells methylated myelin basic protein, histone, and the amino terminus of fibrillarin fused to glutathione S-transferase. Myelin basic protein methylated by PRMT5 contained monomethylated and dimethylated arginine residues. Recombinant glutathione S-transferase-PRMT5 protein expressed in Escherichia coli also contained the catalytic activity. Sedimentation analysis of purified PRMT5 on a sucrose density gradient indicated that PRMT5 formed distinct homo-oligomeric complexes, including a dimer and tetramer, that comigrated with the enzyme activity. The PRMT5 homo-oligomers were dissociated into a monomer in the presence of a reducing agent, whereas a monomer, dimer, and multimer were detected in the absence or at low concentrations of a reducing agent. The results indicate that both covalent linkage by a disulfide bond and noncovalent association are involved in the formation of PRMT5 homo-oligomers. Western blot analysis of sedimentation fractions suggests that endogenous PRMT5 is present as a homo-oligomer in a 293T cell extract. PRMT5 appears to have lower specific enzyme activity than PRMT1. Although PRMT1 is known to be mainly located in the nucleus, human PRMT5 is predominantly localized in the cytoplasm.

Regulation of peripheral lymph node genesis by the tumor necrosis factor family member TRANCE

Proper lymph node (LN) development requires tumor necrosis factor-related activation-induced cytokine (TRANCE) expression. Here we demonstrate that the defective LN development in TRANCE(-/)- mice correlates with a significant reduction in lymphotoxin (LT)alphabeta(+)alpha(4)beta(7)(+)CD45(+)CD4(+)CD3(-) cells and their failure to form clusters in rudimentary mesenteric LNs. Transgenic TRANCE overexpression in TRANCE(-/)- mice results in selective restoration of this cell population into clusters, and results in full LN development. Transgenic TRANCE-mediated restoration of LN development requires LTalphabeta expression on CD45(+) CD4(+)CD3(-) cells, as LNs could not be induced in LTalpha(-/)- mice. LTalpha(-/)- mice also showed defects in the fate of CD45(+)CD4(+)CD3(-) cells similar to TRANCE(-/)- mice. Thus, we propose that both TRANCE and LTalphabeta regulate the colonization and cluster formation by CD45(+) CD4(+)CD3(-) cells in developing LNs, the degree of which appears to correlate with the state of LN organogenesis.

Expression and purification of an active, full-length hepatitis C viral NS4A

The nonstructural protein 3 (NS3) of the hepatitis C virus (HCV) is a bifunctional protein with protease and helicase activities. Nonstructural protein 4A (NS4A) is preceded by NS3 and augments the proteolytic activity of NS3 through protein-protein interaction. The central domain of NS4A has been shown to be sufficient for the enhancement of the NS3 protease activity. However, investigations on the roles of the N-terminal and the C-terminal regions of NS4A have been hampered by the difficulty of purification of full-length NS4A, a polypeptide that contains highly hydrophobic amino acid residues. Here we report a procedure by which one can produce and purify an active, full-length NS4A using maltose-binding protein fusion method. The full-length NS4A fused to the maltose binding protein is soluble and maintains its NS3 protease-enhancing activity.

Effects of titanium prosthesis, offset and size of field of view on bone mineral density measurements using quantitative computed tomography

To estimate the accuracy of quantitative computed tomography (QCT) as a method to measure bone mineral density (BMD) in the vicinity of a titanium prosthesis, we investigated the effects of (1) titanium prosthesis, (2) offset of the longitudinal axis of the bone to be examined from that of the gantry of the CT scanner, (3) size of the field of view (FOV) and (4) the combination of these effects on CT based measurements of mineral density of cortical and cancellous bone specimens. 14 bovine cortical bone parallelepipeds and 14 bovine cancellous bone parallelepipeds were used in this investigation. The bone specimens were scanned with and without a titanium prosthesis, when centered in the gantry of the CT scanner and offset from the axis of the gantry of the CT scanner at a distance of 14 cm. Image data were then reconstructed separately with a FOV of 10 cm and 30 cm. All BMD values taken from CT images obtained under different scanning condition were compared with the BMD values of the corresponding bone parallelepiped obtained under standard condition (centered in the gantry of the CT scanner, 10 cm FOV, without titanium prosthesis). When centered in the gantry of the CT scanner, the mean relative difference of BMD measurements caused by the presence of the titanium prosthesis was less than 1% for both cortical bone and cancellous bone. Size of the FOV had a negligible effect on BMD measurements. Offset at 14 cm, however, caused a significant difference in BMD measurements (p < 0.001). It was concluded that titanium prosthesis did not interfere with BMD measurements of cortical and cancellous bone when both the specimen and prosthesis were centered in the gantry of the CT scanner. However, the effect on BMD measurements of offset at 14 cm combined with the presence of a titanium prosthesis in bone was significant.

The elastic properties of trabecular and cortical bone tissues are similar: results from two microscopic measurement techniques

Acoustic microscopy (30-60 microm resolution) and nanoindentation (1-5 microm resolution) are techniques that can be used to evaluate the elastic properties of human bone at a microstructural level. The goals of the current study were (1) to measure and compare the Young's moduli of trabecular and cortical bone tissues from a common human donor, and (2) to compare the Young's moduli of bone tissue measured using acoustic microscopy to those measured using nanoindentation. The Young's modulus of cortical bone in the longitudinal direction was about 40% greater than (p<0.01) the Young's modulus in the transverse direction. The Young's modulus of trabecular bone tissue was slightly higher than the transverse Young's modulus of cortical bone, but substantially lower than the longitudinal Young's modulus of cortical bone. These findings were consistent for both measurement methods and suggest that elasticity of trabecular tissue is within the range of that of cortical bone tissue. The calculation of Young's modulus using nanoindentation assumes that the material is elastically isotropic. The current results, i.e., the average anisotropy ratio (E(L)/E(T)) for cortical bone determined by nanoindentation was similar to that determined by the acoustic microscope, suggest that this assumption does not limit nanoindentation as a technique for measurement of Young's modulus in anisotropic bone.

The effects of dietary-induced obesity on the biomechanical properties of femora in male rats

OBJECTIVE

To assess the effects of diet-induced obesity (DIO), on the biomechanical and biochemical properties of the femur in mature male rats.

DESIGN AND SUBJECTS

Two groups of male rats were studied. The DIO experimental group was fed a high caloric diet and a 31% sucrose solution as drinking fluid for a month, whereas the control group was fed lab chow and tap water.

MEASUREMENT

Body weight; body water; lean body mass; femoral length; average cortical thickness; outer anteroposterior diameter; outer mediolateral diameter; cortex area; moment of inertia; cortical and cancellous bone hydration; tendon and muscle hydration; ash content of cortical and cancellous bone; ultimate load; deflection at ultimate load; ultimate strength; stiffness; elastic modulus and energy absorption capacity.

RESULTS

'Gainers' (final body weight in excess of three standard error of mean of the controls) were 19.1% heavier, with higher body fat, whereas body water, lean body mass, hydration of cancellous bone and ash content of cortical bone were lower, when compared to controls. Rats that failed to gain weight, despite the high caloric diet, were termed 'resisters' (weight gain less than three standard error of mean of the controls). Ultimate load, deflection at ultimate load and femoral energy absorption capacity were significantly higher in the experimental group when compared to the controls. However, no differences were found among the groups with respect to ultimate stress and stiffness.

CONCLUSION

The weight gain produced by DIO may lead to bone adaptation and improved biomechanics.

TRANCE is a novel ligand of the tumor necrosis factor receptor family that activates c-Jun N-terminal kinase in T cells

A novel member of the tumor necrosis factor (TNF) cytokine family, designated TRANCE, was cloned during a search for apoptosis-regulatory genes using a somatic cell genetic approach in T cell hybridomas. The TRANCE gene encodes a type II membrane protein of 316 amino acids with a predicted molecular mass of 35 kDa. Its extracellular domain is most closely related to TRAIL, FasL, and TNF. TRANCE is an immediate early gene up-regulated by TCR stimulation and is controlled by calcineurin-regulated transcription factors. TRANCE is most highly expressed in thymus and lymph nodes but not in nonlymphoid tissues and is abundantly expressed in T cells but not in B cells. Cross-hybridization of the mouse cDNA to a human thymus library yielded the human homolog, which encodes a protein 83% identical to the mouse ectodomain. Human TRANCE was mapped to chromosome 13q14 while mouse TRANCE was located to the portion of mouse chromosome 14 syntenic with human chromosome 13q14. A recombinant soluble form of TRANCE composed of the entire ectodomain induced c-Jun N-terminal kinase (JNK) activation in T cells but not in splenic B cells or in bone marrow-derived dendritic cells. These results suggest a role for this TNF-related ligand in the regulation of the T cell-dependent immune response.

Identification of cis-regulatory elements in the upstream regulatory region of human papillomavirus type 59

Human papillomavirus type 59 (HPV-59) was cloned from a vulvar intraepithelial neoplasia and the complete nucleotide sequence was determined. This virus is closely related to HPV-18 and -39 (60% homology in nucleotide sequence) and is grouped with the genital HPV types. In the present paper, we demonstrate that the HPV-59 E2 transactivator represses its E6 promoter-mediated transcription. We have also analyzed cis-regulatory elements in the upstream regulatory region (URR) of HPV-59 using chloramphenicol acetyl transferase assays as well as electrophoresis mobility shift assays (EMSA). The results allow for a subdivision of the HPV-59 URR into three regions of activity: distal (nt 7149-7493), central (nt 7493-7742), and proximal (nt 7742-7748). In particular, the 250 bp (nt 7493-7742) of the central region plays an important role as a constitutive enhancer element for the maximal transcription of the E6 promoter. Our results suggest that the transcription factors AP1, Oct1, SP1 and unidentified factors bind to the HPV-59 E6 promoter region, whereas NF1, GRE and TFIID fail to bind despite the presence of putative binding sites in the DNA sequence.

Transforming activities of human papillomavirus type 59 E5, E6 and E7 open reading frames in mouse C127 cells

The DNA sequence from a human papillomavirus type 59 (HPV 59) has been recently determined. The HPV 59 genome consists of 7896 nucleotides (nt). A comparative analysis of this sequence with the sequences of other HPVs revealed the closest homology to HPV 18 (71%). To test the transforming activities of HPV 59 DNA and its gene products, several plasmids expressing HPV 59 open reading frames (ORF) were constructed. The E5, E6, and E7 ORFs of HPV 59 were inserted into pRc/CMV vector containing a promoter of cytomegalovirus to test the transforming activities of these ORFs. When these DNAs were transfected into mouse C127 cells, all three ORFs were independently able to transform C127 cells in the presence of G418, although the full length HPV 59 DNAs failed to induce the focus-formation. The E7 ORF showed the strongest transforming activity and the E5 ORF exhibited the weakest transforming activity. Cell lines transformed by E5, E6, and E7 ORFs were established and they grew anchorage-independently. The presence of HPV 59 ORF DNA was confirmed by polymerase chain reaction (PCR) and Southern blot analysis in HPV 59 ORFs-transformed cell lines.

The accuracy of computed tomography-based linear measurements of human femora and titanium stem

RATIONALE AND OBJECTIVES

The authors investigate the accuracy of computed tomography linear measurement of femora with titanium stem, and the effect of the stem on these measurements.

MATERIALS AND METHODS

Two embedded cadaveric femora, one of them containing a titanium stem, and two cortical bone parallelepipeds were scanned. Thirty-six cross-sections were studied, each measured in two linear directions by the profile window technique. A half-maximum height method was used to determine the cortex-gap-titanium sizes from the computed tomography (CT) images. The accuracy of the measurements from the parallelepipeds, femora, and titanium stem taken from the CT was compared with those taken by a digital caliper of anatomical sections at the same level of the same bone.

RESULTS

Computed tomography measurements of the parallelepipeds were similar to the anatomical size (mean relative error 0.04% +/- 0.63%). The mean error and mean relative error of the cadaveric femora CT with and without the stem were similar to the control parallelepipeds. Higher values of error were found for the titanium stem.

CONCLUSIONS

The half-maximum height method in the profile window provides an accurate measurement of the femoral cortex and the titanium stem. The presence of the titanium stem in the medullary cavity of the femur did not interfere with the measurements of cortical dimensions.

Ultrasound velocity and broadband attenuation over a wide range of bone mineral density

Ultrasound velocity (UV) and broadband ultrasound attenuation (BUA) were studied in human and bovine bone with a wide range of bone mineral density (BMD). The BMD of 98 fresh specimens was measured by quantitative computed tomography: 42 cancellous specimens from women in the age group of 64 +/- 4 years; 51 bovine cancellous and 5 bovine cortical. BMD values ranged from 90 to 400 mg/cm3 for the human cancellous bone, 310 to 870 mg/cm3 for the bovine cancellous bone, and 1750 to 1780 mg/cm3 for the bovine cortical bone. BMD showed a strong linear correlation with apparent density over the entire range of density (r = 0.979). UV of human and bovine cancellous bone was 1480-2650 m/s and 2880-3100 m/s for bovine cortical bone. BUA values were 1-61 dB/MHz/cm for the cancellous specimens and 5-12 dB/MHz/cm for cortical specimens. UV was found to be linear with BMD for all specimens; however, BUA was linear with BMD only for the specimens from elderly women. A quadratic relationship between BUA and BMD was found when the bovine samples were included.

Nucleotide sequence and phylogenetic classification of human papillomavirus type 59

The complete nucleotide sequence of the HPV 59 DNA genome, isolated from a vulvar intraepithelial neoplasia, was determined. It consists of 7896 nucleotides. A comparative analysis of this sequence with the sequences of other HPV types revealed the closest homology to HPV 18 (71%), HPV 45 (70%), and HPV 39 (69%). Phylogenetic analysis of the complete L1 ORFs of HPV 59 and other papillomaviruses exclusively groups all HPVs which have been detected in mucosal lesions into one major branch. This major branch, in turn, includes two specific subgroups containing all high risk viruses associated with malignant mucosal lesions. The motif in the L2 ORF thr-thr-pro-ala-val/ile-leu/ile-asp/asn-val/ile, an extension of a previously reported mucosal motif, is highly conserved in all HPV types detected in mucosal lesions, whereas it is totally absent in those viruses exclusively associated with cutaneous lesions.

P3 promoter element of bovine papillomavirus

The P3 promoter activity of Bovine papillomavirus (BPV) and cis-acting DNA element of P3 promoter required for transcription were examined using chloramphenicol acetyltransferase (CAT) assay. The results show that P3 promoter is a very weak promoter compared to P2 promoter in BPV and E2 transactivator is required for the maximal transcription of P3 promoter in a BPV upstream regulatory region (URR)-dependent manner. Deletion experiments by nuclease Bal-31 were carried out to define P3 promoter element. The DNA sequences between nt 712 and nt 802 of BPV are required for efficient transcription of the P3 promoter. This 90 bp region contains SV40 enhancer core sequences and an ATF binding site.

Norepinephrine overflow in perfused mesenteric arteries of spontaneously hypertensive rats

We examined the overflow of endogenous norepinephrine with electrical stimulation, the associated pressor response, and rate of initial neuronal uptake of [3H]norepinephrine in perfused mesenteric arteries of 7- and 13-week-old spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. The tissues of two rats, a spontaneously hypertensive and a WKY control rat, were simultaneously processed and subjected to the same electrical stimulation. Both absolute and fractional overflow of endogenous norepinephrine during periarterial nerve stimulation (5 and 10 Hz for 1 minute) in the tissue of 7-week-old SHR was significantly greater whereas overflow of 13-week-old SHR was equivalent as compared with that of the age-matched WKY rats. The tissue content of norepinephrine was 20-25% higher in SHR of both ages. There was significantly enhanced [3H]norepinephrine uptake in the tissues of young SHR, but no difference was observed in the older SHR. The pressor response to periarterial nerve stimulation was significantly enhanced in 7-week-old SHR and much more so at the older age as compared with the WKY control rats. Exogenous norepinephrine dose-response curves in the tissues of 7-week-old SHR exhibited a parallel leftward shift, characteristic of a change in sensitivity, whereas that of 13-week-old SHR showed a much steeper slope as compared with the respective WKY control rats. This finding suggests that in addition to smooth muscle supersensitivity, structural alterations had occurred in vasculature of 13-week-old SHR. These data indicate that in SHR both the exocytotic release of norepinephrine and the responsiveness of the vascular smooth muscle cells are enhanced in the developmental stage of hypertension whereas smooth muscle supersensitivity to norepinephrine and nonspecific structural alterations primarily contribute to the maintenance of hypertension at 13 weeks of age.

Norepinephrine release and reuptake by hypothalamic synaptosomes of spontaneously hypertensive rats

We compared the overflow of endogenous norepinephrine during electrical field stimulation, the norepinephrine content, and the rate of initial neuronal uptake of [3H]norepinephrine in synaptosomes isolated from hypothalamus and brainstem of spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats at 7 and 13 weeks of age. The synaptosomes of two rats, a SHR and a WKY rat control, were simultaneously processed and subjected to the same electrical field stimulation. The overflow of endogenous norepinephrine during electrical stimulation (2 Hz, 2 minutes) in the hypothalamic synaptosomes of 7-week-old SHR was significantly greater, whereas the overflow of 13-week-old SHR was equivalent to the age-matched WKY rat. The norepinephrine content of synaptosomes was about the same in SHR and age-matched controls. There was also significantly enhanced [3H]norepinephrine uptake in the hypothalamic synaptosomes of young SHR, but neither the hypothalamic nor the brainstem samples of 13-week-old SHR showed any significant difference in their rate of [3H]norepinephrine uptake. These data are similar to those we observed (unpublished observations) in perfused mesenteric artery system in which norepinephrine release was significantly elevated during periarterial nerve stimulation only in young SHR. Thus, these results suggest that a parallel enhancement of norepinephrine release in hypothalamus with that of peripheral nervous system may play an important role during development of hypertension in young SHR.

Norepinephrine overflow and re-uptake in perfused mesenteric arteries of Dahl salt-sensitive and salt-resistant rats

We compared the overflow of endogenous norepinephrine (NE) upon electrical stimulation, the associated pressor response and rate of initial neuronal uptake of 3H-I-NE in the perfused mesenteric arteries of Dahl salt-sensitive (DS) and salt-resistant (DR) rats on two dietary NaCl regimens (0.4 and 8.0% for 2 weeks) from 4 weeks of age. The tissues of two rats, a DS and a DR control, were simultaneously processed and subjected to the same electrical stimulation. The pressor response and overflow of endogenous NE during periarterial nerve stimulation (5, 10 Hz, 1 min) in the tissue of DS rats on a high-salt diet (HS) were significantly greater, while those of DS on a low-salt diet (LS) were moderately but significantly higher than those of DR rats on either a high (HR) or a low-salt diet (LR). The tissue content of NE in DS rats was significantly lower than DR groups. There was a significantly reduced 3H-I-NE uptake in the tissues of DS rats on both salt diet groups compared with DR rats. A submaximal dose of exogenous NE evoked a significantly greater pressor response amplitude in mesenteric tissues from DS rats on a high-salt diet than in any of the other three groups, suggesting that smooth muscle supersensitivity, either in the density of the NE receptor or in the excitation-contraction coupling system, had been induced in the vasculature of DS rats by feeding them on a high-salt diet for 2 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma clonidine levels in hypertension

Ten patients with essential hypertension were treated orally with clonidine, and the dose was titrated until the diastolic pressure fell below 90 mm Hg or at least 10 mm Hg below baseline, or until a maximum dose of clonidine of 1.2 mg/day was reached. After at least 2 wk on a constant dose of clonidine, the patients were hospitalized and blood pressure and plasma clonidine concentrations were measured by a highly specific and sensitive gas chromatographic, electron-capture method (sensitivity as low as 0.1 ng clonidine/ml). There was good correlation between daily clonidine dose and plasma clonidine concentration. The average blood pressure reduction during 12 hr after clonidine correlated poorly with steady-state plasma levels of clonidine, but when the individual maximum decrease in mean blood pressure was paired with the corresponding peak plasma concentration of clonidine, the correlation was strong.

The specific interaction between LSD and serotonin-binding protein

In this report, we describe the chemical interaction between lysergic acid (LSD) and serotonin-binding protein (SBP) by a three-dimensional spectroscopic technique. This instrument records simultaneously the activation and fluorescence spectra, and plots fluorescence intensity level by a series of isointensity contours. Free LSD exhibits maximum fluorescence at 435 nm with excitation maximum at 330 nm. While SBP-bound LSD shifted its fluoresence and excitation maximum to 465 nm and 375 nm respectively. These results suggest that the drug-protein interaction caused an extensive delocalization of the molecular orbital electrons and thereby lengthen the electronic conjugation of the drug molecule. Such shift was not observed when LSD was incubated with bovine serum albumin under the same condition. This technique is sensitive and requires a small volume of samples. It permits us to determine both free and bound drug in the same sample and provides us specific information about the drug and protein interaction.