Asymmetric expression of antivin/lefty1 in the early chick embryo

Mammalian lefty and zebrafish antivin, highly related to lefty, are shown to be expressed asymmetrically and involved in the specification of the left body side of early embryos. We isolated a chick homologue of the antivin/lefty1 cDNA and studied its expression pattern during early chick development. We found that antivin/lefty1 is expressed asymmetrically on the left side of the prospective floorplate, notochord and lateral plate mesoderm of the chick embryo.

C/EBPalpha is required to maintain postmitotic growth arrest in adipocytes

Terminal differentiation is often coupled with irreversible loss of proliferative potential. The CCAAT enhancer binding protein alpha (C/EBPalpha) preferentially accumulates in postmitotic, differentiated 3T3-L1 adipocytes but declines during tumor necrosis factor alpha (TNFalpha)-induced dedifferentiation. We have discovered that this decline in C/EBPalpha correlates with an increased mitotic growth potential. In order to further investigate the antimitotic activity of C/EBPalpha, we introduced antisense C/EBPalpha RNA into 3T3-L1 cells to block endogenous C/EBPalpha expression. When treated according to the standard differentiation protocol, stable cells lines harboring antisense C/EBPalpha RNA did not differentiate into fat-laden adipocytes, consistent with previous findings (Lin F, Lane MD, Genes Dev 1992;6:533-544). We found that these undifferentiated cells expressing antisense-C/EBPalpha can reenter the cell cycle after mitogenic stimulation at a time in development when parental 3T3-L1 cells cannot. Moreover, the expression profiles of the growth-arrest-associated genes gas1 and gas2 revealed that the antisense C/EBPalpha-expressing cells withdrew from the cell cycle after the period of clonal expansion but failed to progress to the state of least proliferative potential characteristic of terminally differentiated adipocytes.

[Computer-aided 3-D reconstruction and measurement of optic canal and intracanalicular structures]

OBJECTIVE

To reconstruct the human optic canal and its inner structures, and to provide knowledge of this region in detail for optic nerve decompression and further understanding on the pathologic mechanisms of indirect optic nerve injury.

METHODS

6 optic canals and its inner structures were reconstructed by using a computer-aided 3-dimensional (3-D) reconstruction system. Quantitative measurement for the canal wall thickness, bony canal transverse area, optic nerve transverse area, dual sheath transverse area, subarachnoid space transverse area, and subarachnoid space volume were done by means of the computer morphometric analysis system. The detailed spatial relations among intracanalicular structures were also carefully identified on the 3-D models.

RESULTS

The thinnest portion of the canal was the middle part of the medial wall (0.45 +/- 0.35)mm, and the narrowest space was in the middle part of the optic canal [the transverse area was (18.21 +/- 2.50) mm(2)]. The volume of subarachnoid space which can be considered the compensatory space for distention incurred by the hemorrhage, optic nerve edema, or hematoma was (21.16 +/- 4.31) mm(3). At the cranial opening, the middle part and orbital opening, its transverse area was (4.45 +/- 1.12) mm(2), (2.68 +/- 1.32) mm(2), (1.23 +/- 0.83) mm(2), respectively.

CONCLUSIONS

In the middle part, the restraining of the bony canal on injured nerve may be the most powerful. Since the compensatory space was limited, even a tiny amount of blood or swelling of the nerve may cause optic compression. Because the compensatory space for distention gradually decreases from cranial end to orbital end, the middle part and the anterior part of the optic canal and dural sheath are critical in optic nerve decompression.

Stage-specific expression of alpha1,2-fucosyltransferase and alpha1, 3-fucosyltransferase (FT) during mouse embryogenesis

Lex [Galbeta1-4(Fucalpha1-3)GlcNAc] and Ley [Fucalpha1-2Galbeta1-4(Fucalpha1-3)GlcNAc] are both stage-specific embryonic antigens. Lex is first detected on the blastomeres of the 8-cell stage embryo, which correlates with the onset of blastomere compaction. Ley is highly expressed on the surface of the blastocyst, which has been shown to be involved in blastocyst attachment in the mouse. In the present study, mouse alpha1,2-FT (also known as FUT1) and alpha1,3-FT (also known as Fuc-TIV), which were responsible for Lex and Ley formation, were examined in preimplantation stage embryos by reverse transcription-PCR and in situ hybridization. alpha1,3-FT mRNA was detected in all embryos of preimplantation stage, while alpha1,2-FT mRNA emerged in the later stage embryos from 8-cell to 16-cell to the blastocyst. These results indicated the expression of Ley was regulated by alpha1,2-FT. In situ hybridization showed that these two enzyme mRNAs were detected only in morula and blastocyst stage embryos. The alpha1,2-FT and alpha1, 3-FT mRNAs were located in both the inner cell mass and the trophoblast cells. 2-Cell and 4-cell embryos were isolated from the oviduct and cultured in vitro to the 8-cell, morula and blastocyst stage. The expression of alpha1,2-FT and alpha1,3-FT were observed in these embryos developed in vitro; immunohistochemical analysis also showed that Ley expression was positive. These results suggested the stage-specific expression of Ley on the embryos was synthesized by endogenous alpha1,2-FT and alpha1,3-FT rather than transfer from other sources. In addition, the expression of alpha1, 2-FT was differentially regulated and the uterine factor was not prerequisite of the expression of Ley.

Functional genomics: expression analysis of Escherichia coli growing on minimal and rich media

DNA arrays of the entire set of Escherichia coli genes were used to measure the genomic expression patterns of cells growing in late logarithmic phase on minimal glucose medium and on Luria broth containing glucose. Ratios of the transcript levels for all 4,290 E. coli protein-encoding genes (cds) were obtained, and analysis of the expression ratio data indicated that the physiological state of the cells under the two growth conditions could be ascertained. The cells in the rich medium grew faster, and expression of the majority of the translation apparatus genes was significantly elevated under this growth condition, consistent with known patterns of growth rate-dependent regulation and increased rate of protein synthesis in rapidly growing cells. The cells grown on minimal medium showed significantly elevated expression of many genes involved in biosynthesis of building blocks, most notably the amino acid biosynthetic pathways. Nearly half of the known RpoS-dependent genes were expressed at significantly higher levels in minimal medium than in rich medium, and rpoS expression was similarly elevated. The role of RpoS regulation in these logarithmic phase cells was suggested by the functions of the RpoS dependent genes that were induced. The hallmark features of E. coli cells growing on glucose minimal medium appeared to be the formation and excretion of acetate, metabolism of the acetate, and protection of the cells from acid stress. A hypothesis invoking RpoS and UspA (universal stress protein, also significantly elevated in minimal glucose medium) as playing a role in coordinating these various aspects and consequences of glucose and acetate metabolism was generated. This experiment demonstrates that genomic expression assays can be applied in a meaningful way to the study of whole-bacterial-cell physiology for the generation of hypotheses and as a guide for more detailed studies of particular genes of interest.

Tin speciation in the femtogram range in open ocean seawater by gas chromatography/inductively coupled plasma mass spectrometry using a shield torch at normal plasma conditions

A sensitive method for the determination of ultratrace organotin species in seawater is described. The merits and demerits of derivatization methods using Grignard reagent or sodium tetraethylborate (NaBEt4) were evaluated in terms of derivatization efficiency, applicability to the programmed temperature vaporization (PTV) method, and procedural blanks. The sensitivity of the gas chromatography/inductively coupled plasma mass spectrometry (GC/ICPMS) was improved by more than 100-fold by operating the shield torch at normal plasma conditions, compared with that obtained without using it. The absolute detection limit as tin reached subfemtogram (fg) levels. Furthermore, the detection limit in terms of relative concentration was improved 100-fold by using the PTV method, which enabled the injection of a large sample volume of as much as 100 microL without loss of analyte. When the organotin species in seawater were extracted into hexane with a preconcentration factor of 1000 after ethylation with NaBEt4 and a 100 microL aliquot of the extract was injected into the GC, the instrumental detection limit in relative concentration reached 0.01 pg/L in original seawater. Sources of contamination of organotin species during the sample preparation were examined, and a purification method of NaBEt4 was developed. Finally, the method was successfully applied to open ocean seawater samples containing organotin species at the level of 1-100 pg/L.

Computer-aided three-dimensional reconstruction and measurement of the optic canal and intracanalicular structures

OBJECTIVE

To reconstruct the human optic canal and its inner structures and to provide detailed knowledge of this region for optic nerve decompression.

METHODS

Six optic canals and their inner structures were reconstructed using a computer-aided three-dimensional reconstruction system. Quantitative measurement of the canal wall thickness, bony canal transverse area, optic nerve transverse area, dural sheath transverse area, subarachnoid space transverse area, and subarachnoid space volume was done using the computer morphometric analysis system. The detailed spatial relationship among intracanalicular structures was also carefully identified on the three-dimensional models.

RESULTS

The thinnest portion of the canal was the middle part of the medial wall (0.45 +/- 0.14 mm) and the narrowest space was in the middle part of the optic canal (the transverse area was 18.21 +/- 1.20 mm2). The volume of subarachnoid space that can be considered the compensatory space for distention incurred by the hemorrhage, optic nerve edema, or hematoma was 21.16 +/- 4.31 mm3. At the cranial opening, the middle part, and the orbital opening, its transverse area was 4.45 +/- 0.46 mm2, 2.68 +/- 0.54 mm2, and 1.23 +/- 0.34 mm2 respectively.

CONCLUSIONS

Because the compensatory space was limited, even a tiny amount of blood or swelling of the nerve may cause optic nerve compression. Because the compensatory space for distention gradually decreases from cranial end to orbital end, the middle part and the anterior part of the optic canal and dural sheath are critical in optic nerve decompression.

[Effect of anti-vascular endothelial growth factor antibody on the progression of human gastric cancer orthotopic xenotransplanted into nude mice]

OBJECTIVE

To study the inhibiting effect of anti-vascular endothelial growth factor (VEGF) on the growth and metastasis of gastric cancer.

METHODS

The anti-tumor and anti-metastasis effect of anti-VEGF antibody, mitomycin C (MMC) were investigated by means of an orthotopic xenotransplanted model of human gastric cancer SGC-7901 in nude mice which had been randomly divided into 4 groups: control group receiving PBS, group receiving 50 microg/mice anti-VEGF antibody, group receiving 2 mg/kg MMC, and group receiving 50 microg/mice anti-VEGF antibody combined with 2 mg/kg MMC. Anti-VEGF antibody was given i.p. twice a week and MMC was administered i.p. once a week for 8 weeks from day 7 after transplantation. All animals were sacrificed at the end of 10 weeks. The tumor was weighted and the intra-tumoral microvessel density (MVD) was recorded, and the liver was histologically examined in order to discover micrometastasis.

RESULTS

Both anti-VEGF antibody and MMC showed a significant inhibitory effect on the growth of primary tumors; in the combination treatment group the inhibitory effect was more significant than single agent. Liver metastasis developed in 19 of 28 mice (67.9%) of the controls and in 6 of 11 mice (54.5%) receiving MMC. In contrast, liver metastasis occurred in 2 of 10 mice (20%) receiving anti-VEGF antibody and none receiving combination treatment. In addition, the MVD was less significant in the anti-VEGF antibody group and combination treatment group than other groups.

CONCLUSIONS

Anti-VEGF may provide a new approach to the treatment of gastric cancer by inhibiting tumor angiogenesis, and combination of anti-VEGF antibody with MMC could be more effective.

An estimation method for the semiparametric mixed effects model

A semiparametric mixed effects regression model is proposed for the analysis of clustered or longitudinal data with continuous, ordinal, or binary outcome. The common assumption of Gaussian random effects is relaxed by using a predictive recursion method (Newton and Zhang, 1999) to provide a nonparametric smooth density estimate. A new strategy is introduced to accelerate the algorithm. Parameter estimates are obtained by maximizing the marginal profile likelihood by Powell's conjugate direction search method. Monte Carlo results are presented to show that the method can improve the mean squared error of the fixed effects estimators when the random effects distribution is not Gaussian. The usefulness of visualizing the random effects density itself is illustrated in the analysis of data from the Wisconsin Sleep Survey. The proposed estimation procedure is computationally feasible for quite large data sets.

Cord blood is better than bone marrow for generating megakaryocytic progenitor cells

Thrombocytopenia remains an important problem for patients post high-dose chemotherapy and hematopoietic stem cell transplantation. The study of megakaryocytes, the direct precursors of platelets, has been hampered by their relatively low frequency in hematopoietic tissues. In an attempt to obtain a large number of functional megakaryocytic cells, we established a serum-free culture system to grow megakaryocytic progenitor cells derived from normal human bone marrow (BM) and cord blood (CB). Highly purified (purity >95%) CD34+ cells were obtained using magnetic cell sorting (MACS) followed by fluorescence activated cell sorting (FACS). The cells were cultured in a serum-free culture system for 3 weeks in the presence of a single dose of MGDF (50 ng/mL). On days 0, 5, 8, 12, 14, 18, and 21 of culture, the cellularity and morphology were examined. Megakaryocytic cells were monitored by detecting the expression of GPIIIa (CD61), GPIIb/IIIa (CD41) and GPIb (CD42b), and the distribution of megakaryocyte (MK) ploidy was analyzed by two-color flow cytometry. MGDF alone induced maximal nucleated cell expansion at day 14, resulting in a 38.20+/-10.47-fold increase in cell number for CB and a 5.08+/-1.30-fold increase in cell number for BM. On day 14 of the culture, the percentage of CD41-/CD14- cells derived from CB reached 73.54%+/-6.01% giving an absolute number of CD41+/CD14- cells of 27.25+/-2.23 x 10(4)/mL (27,250-fold increase), whilst the percentage of CD41+/CD14- cells derived from BM was only 29.21%+/-5.63% with an absolute number of 1.36+/-0.26 x 10(4)/mL (680-fold increase). Increased expression of GPIIIa occurred the earliest in culture, followed by GPIIb/IIIa, and then GPIb. The majority (81.6%-92.6%) of megakaryocytes (CD41+ cells) on day 14 of culture were 2N, although we did detect some 4N, 8N and greater ploidy cells. In conclusion, CD34+ cells stimulated by MGDF alone generated highly enriched MK progenitor cells at day 14 of serum-free culture. CB stem and progenitor cells have a greater proliferative response to MGDF alone than those derived from BM and may, therefore, prove to be a better source of cells for MK expansion.

Reciprocal regulation of gadd45 by C/EBP alpha and c-Myc

The CCAAT/enhancer-binding protein-alpha (C/EBP alpha) drives the differentiation of murine 3T3-L1 cells to adipocytes through transcriptional activation of phenotype-associated genes via proximal promoter elements. In addition, C/EBP alpha suppresses mitotic growth. We report here that C/EBP alpha directly regulates gadd45 through a C/EBP-binding site in the proximal promoter. A 3 basepair substitution, directed at the most conserved residues of the sequence, reduced C/EBP alpha-mediated transactivation and impaired binding of C/EBP alpha in adipocyte nuclear extracts. We also found that c-Myc antagonized C/EBP alpha-mediated transactivation of gadd45. Analysis of systematically altered forms of C/EBP alpha revealed that c-Myc antagonism targeted the antimitotic, transcriptional activation domain of C/EBP alpha. In addition, we localized the regulatory sequences in the gadd45 promoter that are required for c-Myc antagonism of C/EBP alpha transactivation. Our findings reveal that C/EBP alpha coordinates cellular differentiation and mitotic growth arrest through direct, coordinate regulation of phenotype-associated and growth-arrest-associated genes. In addition, our findings reveal that the reciprocal relation between C/EBP alpha and c-Myc in 3T3-L1 cells includes antagonistic transcriptional control of a growth-arrest-associated gene.

Gene therapy in allergic encephalomyelitis using myelin basic protein-specific T cells engineered to express latent transforming growth factor-beta1

A myelin basic protein (MBP)-specific BALB/c T helper 1 (Th1) clone was transduced with cDNA for murine latent transforming growth factor-beta1 (TGF-beta1) by coculture with fibroblasts producing a genetically engineered retrovirus. When SJL x BALB/c F1 mice, immunized 12-15 days earlier with proteolipid protein in complete Freund's adjuvant, were injected with 3 x 10(6) cells from MBP-activated untransduced cloned Th1 cells, the severity of experimental allergic encephalomyelitis (EAE) was slightly increased. In contrast, MBP-activated (but not resting) latent TGF-beta1-transduced T cells significantly delayed and ameliorated EAE development. This protective effect was negated by simultaneously injected anti-TGF-beta1. The transduced cells secreted 2-4 ng/ml of latent TGF-beta1 into their culture medium, whereas control cells secreted barely detectable amounts. mRNA profiles for tumor necrosis factor, lymphotoxin, and interferon-gamma were similar before and after transduction; interleukin-4 and -10 were absent. TGF-beta1-transduced and antigen-activated BALB/c Th1 clones, specific for hemocyanin or ovalbumin, did not ameliorate EAE. Spinal cords from mice, taken 12 days after receiving TGF-beta1-transduced, antigen-activated cells, contained detectable amounts of TGF-beta1 cDNA. We conclude that latent TGF-beta1-transduced, self-reactive T cell clones may be useful in the therapy of autoimmune diseases.

[Study on the design and application of the contact Nd:YAG laser scalper]

A method of designing the contact laser scalper is presented. The calculations using this method is in good agreement with the measured results in laboratory. Some operations on rabbits using the newly developed contact Nd:YAG laser scalper are performed and shown that the contact Nd:YAG laser is a promising medical equipment.

[A case report of dumbbell neurogenic tumor of the superior mediastinum]

A 15-year-old female was admitted because of the superior mediastinum mass on chest X-rays and sensory loss of ulnar side of the left arm. Computed tomographic scanning and magnetic resonance imaging revealed that the tumor was dumbbell-shaped and invaded the vertebral canal through the intervertebral foramen between C 7 and Th 1. At first laminectomy of vertebrae (C 6-Th 1) was made in a prone position and intra-spinal portion of the tumor was resected. Then the patient was placed in a supine position and the chest was opened by left hemicollar incision and sternotomy to the 2nd intercostal space. The tumor was divided into two parts at the level of 1st rib and completely removed. The pathological diagnosis was schwannoma. This procedure is safe and useful for dumbbell type tumor located in superior mediastinum, especially in case of large tumor from neck to the thoracic cavity.

[Prognostic value of tumor vascularity in gastric carcinoma]

OBJECTIVE

To determine whether tumor angiogenesis correlates with progression of gastric carcinoma.

METHOD

Microvessel counts (MVC) of 131 specimens resected from patients with gastric carcinoma were investigated by immunohistological staining with a monoclonal antibody against F-VIII RAg, counting the mean number of microvessels in the five areas of highest vascular density under 200 times magnification microscopy. Correlation among MVC, various clinicopathologic factors, and prognosis was studied.

RESULT

MVC increased with TNM stage, the MVC of patients with advanced stage disease was significantly higher than that of early stage patients (P < 0.01). MVC was significantly higher in tumors with deep penetration (P < 0.05), lymph node metastasis (P < 0.001) and distant metastasis (P < 0.05) than in those without invasion and such metastasis. The recurrence rate after curative resection in hypervascular group (MVC > or 16) was 58.4%, which was significantly higher (P < 0.05) than that in the hypovascular group (MVC < 16). Moreover, the prognosis of patients with a high MVC was significantly poorer than that of those with a low MVC. The probability of 5 year survival rate was estimated by P = e(1.6231-0.1036 x MVC)/1 + e(1.6231-0.1036 x MVC). Multivariate analysis indicated that MVC is an independent prognostic factor in gastric cancer.

CONCLUSION

Angiogenesis within gastric cancer is an indicator of tumor behavior and may identify patients at higher risk for recurrence and poorer prognosis.

A fast estimate of electrostatic group contributions to the free energy of protein-inhibitor binding

Dissecting ligand-protein binding free energies in individual contributions of protein residues (which are referred to here as 'group contributions') is of significant importance. For example, such contributions could help in estimating the corresponding mutational effects and in studies of drug resistance problems. However, the meaning of group contributions is not always uniquely defined and the approximations for rapid estimates of such contributions are not well developed. In this paper, the nature of group contributions to binding free energy is examined, focusing particularly on electrostatic contributions which are expected to be well behaved. This analysis examines different definitions of group contributions; the 'relaxed' group contributions that represent the change in binding energy upon mutation of the given residue to glycine, and the 'non-relaxed' group contributions that represent the scaled Coulomb interaction between the given residue and the ligand. Both contributions are defined and evaluated by the linear response approximation (LRA) of the PDLD/ S method. The present analysis considers the binding of pepstatin to endothiapepsin and 23 of its mutants as a test case for a neutral ligand. The 'non-relaxed' group contributions of 15 endothiapepsin residues show significant peaks in the 'electrostatic fingerprint'. The residues that contribute to the electrostatic fingerprint are located in the binding site of endothiapepsin. They include the aspartic dyad (Asp32, Asp215) with adjacent residues and the flap region. Twelve of these 15 residues have a heavy atom distance of <3.75 A to pepstatin. The contributions of 8 (10) of these 12 residues can be reconciled with the calculated 'relaxed' group contributions where one allows the protein and solvent (solvent only) to relax upon mutation of the given residue to glycine. On the other hand, it was found that residues at the second 'solvation shell' can have relaxed contributions that are not captured by the non-relaxed approach. Hence, whereas residues with significant non-relaxed electrostatic contributions are likely to contribute to binding, residues with small non-relaxed contributions may still affect the binding energy. At any rate, it is established here that even in the case of uncharged inhibitors it is possible to use the non-relaxed electrostatic fingerprint to detect 'hot' residues that are responsible for binding. This is significant since some versions of the non-relaxed approximation are faster by several orders of magnitude than more rigorous approaches. The general applicability of this approach is outlined, emphasizing its potential in studies of drug resistance where it is crucial to have a rapid way of anticipating the effect of mutation on both drug binding and catalysis.

UV photopolymer materials and technique for making laser glass

A technique and the materials required for making laser glass are described. The technique includes cleaning glass plates, coating UV photopolymer materials onto the glass plates, attaching a master hologram to the plates, using exposure to UV light to cure the coating, screen printing, vacuum film depositing, and covering the plates with a protective coating. The UV photopolymer material is composed of a photoinitiator, a monomer, an oligomer, and other additives. The experimental results show that the laser-glass products have a high resistance to alkali, acid, heating, and UV irradiation.

Conserved and sexually dimorphic behavioral responses to biogenic amines in decapitated Drosophila

A preparation of decapitated Drosophila melanogaster has been used for direct application of drugs to the nerve cord. Serotonin, dopamine, and octopamine stimulate locomotion and grooming, showing distinguishable effects that often are potentiated by addition of the vertebrate monoamine oxidase-inhibitor hydrazaline. Many of the hydrazaline-induced effects are sexually dimorphic, with males showing greater responses than females. Behaviors similar to those induced by dopamine can be induced by application of the vertebrate dopamine D2-like receptor agonist quinpirole, whose effects are also sexually dimorphic. In contrast, vertebrate D2-like and D1-like dopamine antagonists result in akinesic states, and D1-like agonists selectively stimulate grooming. These data indicate that Drosophila nerve cord amine receptors are coupled to reflexive behaviors similar to those stimulated by brain dopamine receptors in vertebrates.

Lyme borreliosis in transgenic mice tolerant to OspA from Borrelia burgdorferi 25015

Lyme borreliosis in transgenic mice tolerant to Borrelia burgdorferi outer surface protein A (OspA) from the weakly virulent B. burgdorferi 25015 was assessed because the response to OspA has been implicated in protective immunity and is suspected in disease pathogenesis. B. burgdorferi 25015 is infectious but does not cause significant arthritis in C3H/HeN mice. Tolerance of mice to B. burgdorferi N40 OspA had no effect on disease. Since B. burgdorferi N40 is more virulent than and genetically distinct from B. burgdorferi 25015, the generality of these findings was investigated. OspA-25015-transgenic mice were tolerant to OspA-25015 and did not develop OspA antibodies or cellular responses following immunization with OspA-25015. The development and resolution of Lyme arthritis was similar in transgenic and nontransgenic littermates, suggesting that ablation of the OspA-25015 response does not cause B. burgdorferi 25015 to become more arthritogenic.

Response of cultured cerebral artery smooth muscle cells to the nitric oxide vasodilators, nitroglycerin and sodium nitroprusside

We characterized the response of soluble guanylyl cyclase in smooth muscle cells cultured from cerebral vessels to the nitric oxide (NO)-producing vasodilators, nitroglycerin (NTG) and sodium nitroprusside (SNP) and determined the ability of these agents to induce tolerance. Smooth muscle cells were isolated from porcine basilar, anterior and middle cerebral, and internal carotid arteries. Following an initial series of experiments using NTG at various concentrations and times of exposure to determine conditions, concentration-response curves of intracellular guanosine 3',5'-cyclic monophosphate (cGMP) to NTG and SNP were determined in cells pretreated for 1 h with 100 mumol NTG to induce tolerance and compared with response curves in control cells. Basal cGMP levels were 2.1 +/- 0.4 pmol/mg cell protein (n = 16). Both NTG and SNP increased cGMP in nontolerant cells, and SNP was more effective. Maximum concentrations of SNP (1 mmol/L) increased cGMP to 163 +/- 5.9 pmol/mg versus 21 +/- 2.4 pmol/mg for 1 mmol/L NTG (p < 0.01). Cells made tolerant to NTG were unresponsive to NTG up to 1 mmol/L but remained responsive to SNP. However, the response curve to SNP was significantly depressed by approximately 25%. Following washout of NTG in tolerant cells, the response of cGMP to SNP returned to control within 12 h, while response to NTG required 36 h. Similar experiments were conducted in cells initially made tolerant to SNP. These results indicate that cerebral artery smooth muscle cells in culture express a functioning soluble guanylyl cyclase and the enzymes that are necessary to metabolize NTG to NO. Prolonged exposure of the cells to NTG induced tolerance as well as cross-tolerance to SNP.

[The Selaginella tamariscina (Beauv.) Spring complex in the treatment of experimental diabetes and its effect on blood rheology]

Experiments have revealed that in treating rats for diabetes induced by alloxan, the Selaginella tamariscina complex injection given intraperitoneally (25g/kg) for 12 days helps lower the levels of blood sugar and serum lipid peroxide, as well as increase the concentration of serum insulin. Histologic observation has shown that this injection could repair the structure of pancreatic inlet B cells injured by alloxan.

[Supervision and evaluation of vaccination coverage rates in Jiangsu province]

Comprehensively, this paper evaluated the actual vaccination coverage rates in Jiangsu province, using geometric averages to weigh vaccination coverage rates through a) regular and irregular investigation b) conventional report rates and c) registration rates of children at the right age of vaccination. Results showed that the comprehensive method of using vaccination coverage rates for evaluation was better than the conventioned index which had been used before.

[Prevention of epidural scar adhesion following lumb spine operation]

Four biomaterials including pork fat (PF), glutaradehyde crosslinked pork peritonium (GCP), glutaradehyde cross-linked human amnion (GCA) and freeze-dried human amnion (FDA) dura were compared for their ability to prevent the dura from adhesion in 24 dogs. Noncontiguous laminectomies were performed on each dog. Laminectomized areas where the above mentioned 4 materials put randomly were served as experimental groups while laminectomized areas with autologous fat transplants put in place were served as standard control and empty control was set with the area left untreated. The formation of fibrosis and the adhesion of the dura were evaluated at 1, 2, 3, 4, 6, 12 weeks after operation by using a double-blind protocol. Methods of observation included gross anatomical evaluation, histological evaluation, computer-assisted image analysis, fibroblasts counting and measurement of SCEP. The results showed: 1. The epidural scar arose from the raw surface of erector spinal muscles and the bony edges created by the procedure; 2. Putting a suitable obstructor between the dura and the erector spinae muscle would make dura be exempted from adhesion; 3. The interpositional membrane should be tucked in between the bony edges in close proximity to the bony surface without leaving any room; 4. GCA seems to be efficient in preventing dural adhesion and reducing the invasion of the scar tissue in the spinal canal.

[Solitary plasmacytomas of bone and extramedullary plasmacytomas]

Among plasma cell disorders, solitary plasmacytoma (solitary plasmacytoma of bone, SPB and extramedullary plasmacytoma, EMP) is rare as compared with multiple myeloma (MM). Furthermore, the relationship between solitary plasmacytoma and MM remains unclear. Between 1960 and 1994, 24 patients with SPB and 20 with EMP were treated. The criteria for diagnosis were: (1) no evidence of other lesions based on clinical and radiologic examinations; (2) biopsy evidence of a plasma cell neoplasm; (3) bone marrow biopsy specimen with negative findings (less than 10% plasma cells); (4) no anemia, hypercalcemia or renal involvement. The average follow-up period was 112 months (from 6 to 360 months). Fifty-four percent of patients with SBP and 40% of patients with EMP developed MM, however, there was no significant statistical difference between SPB and EMP (P > 0.05). We suggested that solitary plasmacytomas be classified as two types, latent and aggressive. The former was histologically well-differentiated plasmacytoma. The latter was poorly differentiated tumors which easily progress to MM. The treatment of choice is wide excision or thorough curettage, by cryogenic necrosis with liquid nitrogen or cautery of the bony wall with phenol and the cavity filled with bone grafts or cementation. All patients with apparently isolated plasmacytoma should receive local radiotherapy after operation. Adjuvant chemotherapy should be given if the tumour turns out to be poorly differentiated, in order to delay their progression to MM.

Lyme borreliosis in transgenic mice tolerant to Borrelia burgdorferi OspA or B

The evolution of Lyme borreliosis in transgenic mice tolerant to Borrelia burgdorferi outer surface proteins (Osps) A or B was assessed to investigate the role of immunity to OspA or B in infection and pathogenesis of Lyme disease. Antibodies to OspA or B protect immunocompetent C3H/HeJ or C.B.17 severe combined immunodeficient (scid) mice from challenge with B. burgdorferi. Moreover, arthritis in infected C3H mice resolves with the rise of high titers of B. burgdorferi specific antibodies, including OspA and B, whereas disease persists in scid mice--suggesting that the regression of arthritis may be due to the development of borreliacidal OspA or B antibodies. To evaluate the course of Lyme borreliosis in OspA or B tolerant mice we developed transgenic mice that expressed OspA or B under control of the major histocompatibility complex (MHC) class I promoter. Mice carrying OspA or B transgenes on a C3H/HeJ (C3H, disease-susceptible) or C57BL/6 (B6, disease-resistant) background, immunized with OspA or B, did not mount a humoral or cellular immune response to OspA or B, respectively, but responded normally to other B. burgdorferi antigens. The evolution of Lyme borreliosis, including infection and the development of arthritis and carditis, was similar in transgenic and nontransgenic littermates suggesting that an OspA or B immune response is not singularly involved in either the genesis or regression of Lyme disease in C3H or B6 mice.

Selection of variant Borrelia burgdorferi isolates from mice immunized with outer surface protein A or B

A nonclonal population of Borrelia burgdorferi N40 (passage 3) that survived protective immunity following challenge inoculation of outer surface protein (Osp) A- or B-hyperimmunized mice were characterized for the molecular basis of evasion of immunity. Two of six B. burgdorferi isolates, cultured from OspA-immunized mice, had antigenic diversity in the carboxyl terminus of OspA and did not bind to the protective OspA monoclonal antibody designated IXDII. However, OspA-immunized mice challenged with these variants were fully protected. Moreover, B. burgdorferi isolates with a point mutation in ospB, which results in a truncated OspB that does not bind to protective OspB monoclonal antibody 7E6C, were frequently enriched after infection of OspB-immunized mice. These studies suggest that the incomplete efficacy of an OspA- or OspB-based vaccine may be partly due to immunomediated in vivo selective pressure, resulting in the persistence of some spirochetes that do not bind to protective antibodies.

C-natriuretic peptide but not atrial natriuretic peptide increases cyclic GMP in cerebral arterial smooth muscle cells

A-type natriuretic peptide (ANP) is found primarily in the heart and is released into the circulation. C-type (CNP) is found principally in the brain and has also been detected in the systemic circulation. When injected, both peptides produce vasodilatation most likely by elevation of guanosine 3'5'-cyclic monophosphate (cGMP) in smooth muscle cells via two distinct receptors, NPR-A and NPR-B. In this present study, we determined the effects of these two peptides on intracellular cGMP in smooth muscle cells cultured from pig cerebral and peripheral arteries. In smooth muscle cells cultured from the left anterior descending coronary artery, ANP and CNP increased cGMP with equal potency and efficacy (EC50 for ANP and CNP, 3.6 +/- 0.2 x 10(-8) M and 6.7 +/- 0.8 x 10(-8) M, respectively). In contrast, in smooth muscle cells from cerebral arteries, ANP was without effect while CNP increased cGMP in a concentration dependent manner (EC50: 9.6 +/- 1.7 x 10(-8) M). Stimulation of the soluble guanylyl cyclase with either nitroglycerin or nitroprusside was equivalent in the two cell types. The pattern of response of intracellular cGMP to CNP and ANP in isolated intact arteries from brain and heart was similar to that found in the cultured cells. These results suggest that smooth muscle cells in cerebral arteries express only NPR-B while cells from peripheral arteries can express both NPR-A and NPR-B.

Cloning sequencing and expression of the gene encoding the VP2 protein of the human group B rotavirus, ADRV

Adult diarrheal rotavirus, ADRV, is a noncultivable human group B rotavirus. A complete cDNA copy of ADRV gene segment 2 has been cloned and sequenced. Gene segment 2 contains 2844 bases and encodes one long open reading frame beginning at base 14 and terminating at base 2812. Gene 2 encodes a protein containing 933 amino acids with a calculated molecular weight of 105.6 kDa and a pl of 5.5. The gene 2 polypeptide contains significant homology with the VP2 protein which comprises the core of group A rotavirus strains. The gene 2 protein has been expressed in a rabbit reticulocyte lysate in vitro and is identical in molecular mass with a protein previously demonstrated to be present on iodinated EDTA-treated virions and from in vitro translations of total ADRV mRNA. A recombinant baculovirus containing gene segment 2 has been constructed and used to express the encoded VP2 equivalent protein. The expressed VP2 protein is immunoprecipitable by hyperimmune anti-ADRV serum, porcine group B infection serum, and human convalescent serum but not by hyperimmune serum to group A rotavirus. Our results suggest that ADRV gene segment 2 encodes the VP2 protein equivalent to group A rotavirus strains present in the core of the group B virion.

[The efficacy and side reactions in humans immunized with Danish strain of dried BCG of Shanghai]

A procedure of keeping Danish BCG strain 2 is reported. The strain is cultivated in Bile potato Medium and Suton Potato Medium alternatively with incubation periods of two weeks. Lyophilized vaccine produced by using seeds derived from this strain gives better immunogenicity and lower side reaction to new-born babies and has better thermostability in compare with vaccines derived from strains of Beijing, Brazil, CCCP, France of Hungary.

Sera from patients with chronic Lyme disease protect mice from Lyme borreliosis

Sera from selected patients with Lyme disease in different stages were used to passively immunize mice against Borrelia burgdorferi challenge to determine if human antibodies could protect the animals from infection. Sera from 2 patients with late-stage Lyme disease that contained strong antibody reactivity to proteins in B. burgdorferi lysates, including antibodies to the outer surface proteins (Osps) A and B, partly protected mice from infection after challenge with a small inoculum (10(2)) of B. burgdorferi. Mice immunized with sera from either of these 2 patients developed significantly fewer infections from the borreliae (patient 1 serum, 5%; patient 2 serum, 25%) relative to control mice (patient 1 serum, 90%; patient 2 serum, 74%). In contrast, sera from 2 patients with early or late Lyme disease that lacked antibodies reactive to OspA and OspB did not confer protection. Immunity appeared to be related, at least in part, to the presence of a strong humoral response to the Osps. These results suggest that during prolonged infection, some patients develop an immune response that may be partly protective against reinfection with B. burgdorferi. Therefore, although most patients do not mount a strong humoral response to the Osps during natural infection, vaccination with an Osp may elicit protective immunity.

The effects of 1,25-dihydroxyvitamin D3 on osteoclast formation in fetal mouse metatarsal organ cultures

We have previously described a model system, using 15-day fetal mouse metatarsals cultured in serumless medium, in which osteoclasts and their precursors develop from in situ progenitors in a manner which is similar, both temporally and spatially, to that which occurs in vivo. In this report we evaluate the role of the osteotropic hormone 1,25-dihydroxyvitamin D3 (1,25-D3) on osteoclast formation in this model system by characterizing its effects on proliferation, differentiation, and fusion of cells of the osteoclast lineage. Morphologic evaluation was used to enumerate osteoclast precursors, mono- and multinucleate osteoclasts, and osteoclast nuclei in serial paraffin sections. Dose response data reveal a significant stimulation of osteoclast formation by 1,25-D3 in the range of 0.6 nM to 40 nM, and kinetic analyses suggest that these effects are on proliferation of osteoclast progenitors as well as on differentiation of precursors to form osteoclasts. A single 48 h exposure between day 4 and 6 of culture is necessary and sufficient to induce maximal osteoclast formation, while continuous exposure beyond this "critical period" inhibits multinucleate osteoclast formation. Simultaneous treatment with indomethacin inhibits the effects of 1,25-D3, while treatment with PGE2 stimulates osteoclast formation without significantly increasing precursor numbers, or inhibiting multinucleate osteoclast formation. These results suggest that the effect of 1,25-D3 to induce differentiation of precursors to form mono- and multinucleate osteoclasts is mediated by endogenous prostaglandin synthesis. On the other hand, the inhibition of polykaryon formation observed with continuous 1,25-D3 treatment, does not appear to be a prostaglandin mediated phenomena.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of atrial natriuretic peptide receptors in vascular smooth muscle cells: role of cGMP

We tested the hypothesis that intracellular guanosine 3',5'-cyclic monophosphate (cGMP) regulates atrial natriuretic peptide (ANP) receptors. The effect of chronic exposure to ANP, sodium nitroprusside (SNP), and 8-bromo-cGMP (8-BrcGMP) on ANP receptors and cGMP formation was determined in guinea pig thoracic aorta smooth muscle cells (TASM) and in coronary artery smooth muscle cells (CASM). TASM express both the ANP-activated guanylyl cyclase (B-receptor) and the clearance receptor (C-receptor) and respond to ANP with increased cGMP. CASM exhibit only the ANP C-receptor. In TASM, 24-h treatment with 1 microM atriopeptin (AP) III [rat ANP-(103-126)] caused a sixfold increase in basal cGMP levels, which were unaltered in CASM. In AP III-treated TASM, maximal binding of 125I-labeled AP III (Bmax) was reduced 40% while affinity [dissociation constant (KD)] was unaltered. In CASM, Bmax and KD were not affected. In treated TASM, washed free of AP III, acute dose-response curves of cGMP to AP III were not different from that in untreated cells. In both TASM and CASM, basal cGMP levels were elevated and Bmax was decreased by 6-h treatment with SNP. SNP did not alter the acute response of cGMP to AP III. In both cell types, 8-BrcGMP for 6 h caused reduction in Bmax. These findings support the conclusion that elevated cGMP was necessary for ANP-induced downregulation of receptors. The unaltered responsiveness of cGMP to AP III suggests the B-receptor was not altered and the reduced Bmax was due to decreased C-receptor.

Evasion of protective immunity by Borrelia burgdorferi by truncation of outer surface protein B

We analyzed variability in outer surface protein B (OspB) from Borrelia burgdorferi (Bb), the causative agent of Lyme disease, to determine how Bb escapes immune destruction. We have shown that vaccination with OspB from Bb strain B31 protected mice from infection with Bb B31 but not against Bb N40. The present study demonstrates that Bb N40 spirochetes which evade vaccination immunity to OspB have a truncated form of OspB, due to a TAA stop codon at nucleotide 577. In contrast, Bb N40 spirochetes that express full-length OspB are unable to infect mice immunized with OspB, analogous to our previous studies with Bb B31. Mapping of the OspB antibody response shows that epitopes in the C terminus of OspB are surface-exposed and bind protective monoclonal and polyclonal antibodies. This suggests that the C terminus of OspB is important for eliciting a protective immune response to OspB. Truncation or modification of outer surface proteins that do not bind protective antibody may be a means by which Bb evades host defenses.

Identification and baculovirus expression of the VP4 protein of the human group B rotavirus ADRV

A complete cDNA copy of the fourth RNA segment of the human group B rotavirus adult diarrheal rotavirus (ADRV) has been cloned into lambda phage and excised into plasmid pSK Bluescript. Gene segment 4 contains 2,303 bases and encodes one long open reading frame beginning at base 16 and terminating at base 2263. The encoded protein contains 749 amino acids, with a calculated molecular mass of 84.4 kDa and a pI of 6.1. Gene 4 cDNA was inserted into a recombinant baculovirus via homologous recombination. The gene 4 polypeptide migrates at 84 kDa when expressed either by a recombinant baculovirus or in vitro in a rabbit reticulocyte lysate. The gene 4 protein is immunoprecipitable by hyperimmune serum to ADRV, human ADRV convalescent-phase serum, a porcine group B rotavirus infection serum, and a monoclonal antibody made to ADRV virion. Guinea pig hyperimmune serum to the baculovirus-expressed ADRV VP4 protein recognizes virus and immunoprecipitates an 84-kDa protein from in vitro translations of total ADRV mRNA. In addition, the gene 4-encoded protein shares significant amino acid identity and similarity with the group A rotavirus VP4 protein. This information, together with our previous identification of an 84-kDa protein present on iodinated intact virion but not EDTA-treated ADRV, suggests that gene 4 encodes the VP4 protein equivalent present on the outer capsid of ADRV. The ADRV VP4 protein is also 58% identical to the IDIR rat group B rotavirus gene segment 3 protein. The substantial differences between these two group B VP4 proteins suggests that they are distantly related and likely to define two different group B rotavirus VP4 serotypes. The baculovirus-expressed VP4 protein should be useful for developing serotyping reagents and tests for human and animal group B rotaviruses as well as for addressing the role of VP4 in ADRV neutralization.

[Enhancement of bleomycin or hyperthermia induced tumor cell damage by ADPRT inhibitor]

Enhancement of tumor cell damage by ADPRT inhibitor, 3-aminobenzamide (3AB) was investigated. 3AB could inhibit DNA strand break repair in HeLa S3 cells after treatment with bleomycin. 3AB was able to lower the clonogenic ability of HeLa S3 cells after bleomycin treatment and hyperthermia. 3AB could also prevent potentially lethal damage repair (PLDR) in HeLa S3 cells treated with bleomycin. This work presents some experimental evidence and theoretical background for the possible use of 3AB as a sensitizer in the treatment of cancer.

Rhizobium leguminosarum CFN42 lipopolysaccharide antigenic changes induced by environmental conditions

Four monoclonal antibodies were raised against the lipopolysaccharide of Rhizobium leguminosarum bv. phaseoli CFN42 grown in tryptone and yeast extract. Two of these antibodies reacted relatively weakly with the lipopolysaccharide of bacteroids of this strain isolated from bean nodules. Growth ex planta of strain CFN42 at low pH, high temperature, low phosphate, or low oxygen concentration also eliminated binding of one or both of these antibodies. Lipopolysaccharide mobility on gel electrophoresis and reaction with other monoclonal antibodies and polyclonal antiserum indicated that the antigenic changes detected by these two antibodies did not represent major changes in lipopolysaccharide structure. The antigenic changes at low pH were dependent on growth of the bacteria but were independent of nitrogen and carbon sources and the rich or minimal quality of the medium. The Sym plasmid of this strain was not required for the changes induced ex planta. Analysis of bacterial mutants inferred to have truncated O-polysaccharides indicated that part, but not all, of the lipopolysaccharide O-polysaccharide portion was required for binding of these two antibodies. In addition, this analysis suggested that O-polysaccharide structures more distal to lipid A than the epitopes themselves were required for the modifications at low pH that prevented antibody binding. Two mutants were antigenically abnormal, even though they had abundant lipopolysaccharides of apparently normal size. One of these two mutants was constitutively unreactive toward three of the antibodies but indistinguishable from the wild type in symbiotic behavior. The other, whose bacteroids retained an epitope normally greatly diminished in bacteroids, was somewhat impaired in nodulation frequency and nodule development.

Small-bowel carcinoid presenting in association with a phytobezoar

An unusual case of a recurrent, postoperative, small-bowel obstruction is presented. The obstruction was due to a phytobezoar proximal to the site of a primary carcinoid of the small bowel. The radiologic findings of a mobile, intraluminal filling defect and a more distal, fixed mural mass are reviewed. The cause of the recurrent obstruction was likely a "ball-valve" effect of the phytobezoar at the site of stenosis caused by the carcinoid. This case emphasizes the value of small-bowel imaging in repeated small-bowel obstruction.

Expression of the major inner capsid protein of the group B rotavirus ADRV: primary characterization of genome segment 5

A complete cDNA copy of the fifth RNA segment of the human group B rotavirus, ADRV, has been cloned into plasmid AD512. Gene segment 5 contains 1269 bases and encodes one long open reading frame of 391 amino acids beginning at base 31 and terminating at base 1203. The gene 5 polypeptide, expressed in vitro in a rabbit reticulocyte lysate, comigrates with the 44-kDa major inner capsid protein present on EDTA treated ADRV virions. The gene 5 protein is immunoprecipitable by hyperimmune serum to ADRV, human ADRV convalescent serum and by a group B-specific monoclonal antibody. In addition, this protein shares amino acid identity and similarity with the VP6 proteins from group C and group A rotavirus strains. The ADRV VP6 equivalent protein appears to be more closely related to the group C VP6 than the Group A VP6 polypeptide and a common ancestral rotavirus VP6 precursor protein is suggested. As a result, the fifth RNA segment of ADRV defines the major inner capsid protein, or VP6 equivalent, in the group B rotavirus. Expression of the ADRV VP6 equivalent protein is potentially useful for evaluating the prevalence of serum antibodies to group B rotavirus in human and animal populations as well as for generating antibodies for the direct detection of group B rotavirus antigen.

[Synthesis and animal experiments of ethylnitrosourea]

Ethylnitrosourea (ENU) was synthesized with raw materials such as ethylamine and sodium nitrite. The product was a yellowish powder. Its melting point, solubility and infrared absorption spectrum coincided with those reported in the literature. The result form elementary analysis for the product was almost the same as the theoretical value. The product was applied to rats by various methods. It was found that ENU was a cancerogenic compound, especially to the nervous system. More details about the animal experiments will be published in some other papers.

Morphology and morphogenesis of viruses of hemorrhagic fever with renal syndrome. II. Inclusion bodies--ultrastructural markers of hantavirus-infected cells

Three distinctive types of viral inclusion bodies were identified in hantavirus-infected cells by thin-section electron microscopy. The inclusion bodies, designated granular, granulofilamentous, and filamentous, were intracytoplasmic and closely associated with the rough endoplasmic reticulum and Golgi cisternae. Virus specificity of the inclusions was verified by immune colloidal gold and immunoperoxidase labeling. The inclusion bodies were a common morphological marker for 13 strains of hantaviruses studied, irrespective of their origin.

Antigenic characterization and ELISA detection of adult diarrhea rotaviruses

Recently, severe epidemics of diarrhea among both adults and children in China have been associated with an agent called adult diarrhea rotavirus (ADRV). We have studied ADRV from two areas of China (Jinzhou and Guangxi) and compared them with prototype group A, B, and C rotaviruses. The viral genomes were compared by electrophoresis of the RNA genome segments in polyacrylamide gels, and the antigenic relatedness of these viruses was examined by immune electron microscopic studies using virus preparations of either double- or single-capsid particles. Hyperimmune antisera (guinea pig and rabbit) to one strain of ADRV reacted with high titers with other strains of ADRV and with single-shelled capsids of a porcine group B rotavirus. The antisera to ADRV did not react with either group A or group C rotaviruses. Antisera to either bovine or porcine group B rotaviruses reacted with ADRV but not with the group A or group C viruses. Antisera to group A or group C virus reacted only with their respective homologous virus. These results and those of immunofluorescence studies place the human ADRV rotaviruses from China among the group B rotaviruses. We also report the development of an ELISA to detect ADRV; this ELISA should be useful for defining the epidemiology of these recently described rotaviruses.

Changes in plasma concentrations of thyroxine and triiodothyronine in beef steers fed different levels of propylthiouracil

Three Latin-square trials were conducted to determine the effects of feeding the thyroid depressant propylthiouracil (PTU) on plasma concentrations of thyroxine (T4) and triiodothyronine (T3) in feedlot steers. In trial 1, four steers were fed 0, 1, 2 or 4 mg PTU/kg body weight daily during five 35-d experimental periods. In trial 2, eight steers were fed 0, .5, 1 or 2 mg PTU/kg body weight daily during five 28-d periods. In trial 3, three steers were fed 0, 1 or 4 mg PTU/kg body weight daily during the first 3 d in each of three 28-d periods. In general, feeding PTU caused increases in plasma T4 concentrations that peaked 5 to 7 d after feeding started. Concurrently, T3 concentrations tended to decrease when PTU was fed. The effects of PTU on hormone concentrations were apparent within approximately 1 to 4 h after PTU feeding started. Furthermore, when PTU was not fed, T4 and T3 concentrations appeared to have rhythmic cycles of 90 and 111 min, respectively, and PTU treatment appeared to interrupt this cyclical pattern. After the initial PTU response, the dose response relationship between PTU level and plasma hormone concentration was not linear. Both 4 and 2 mg PTU appeared to depress both T4 and T3 concentrations, suggesting direct inhibition of the thyroid gland and, for the 1-mg PTU treatment, T4 tended to stabilize at concentrations significantly greater than for 0 mg PTU, while T3 concentrations for 1 mg PTU were slightly lower than for 0 mg PTU.(ABSTRACT TRUNCATED AT 250 WORDS)

Triiodothyronine and thyroxine during gestation in dairy cattle selected for high and low milk production

Circulating thyroxine, triiodothyronine, and prolactin were analyzed by radioimmunoassay from two groups of pregnant heifers representing genetic populations that differed by 685 kg milk in their first lactation. At 100 days of gestation, blood samples were taken every 15 min for prolactin assay and every 2 h to determine variations of thyroid hormone serum concentration from 0800 to 2000. Basal serum prolactin concentrations in the two genetic groups were not significantly different. A pattern was consistent for both triiodothyronine and thyroxine; concentrations were lower in the morning and higher during the afternoon. Serum triiodothyronine means were not different in the high-producing (1.84 ng/ml) and low-producing heifers (1.86 ng/ml). Serum thyroxine concentrations were significantly higher in the low-producing heifers (67.84 ng/ml) than in high-producing heifers (59.18 ng/ml). The higher thyroxine concentration in pregnant heifers with lower producing ability suggests a negative relationship of thyroxine to milk yield potential.

Changes in plasma concentrations of thyroxine, triiodothyronine, cholesterol and total lipid in beef steers fed ronnel

An experiment with eight beef steers was conducted to determine the patterns of change for plasma concentrations of thyroxine (T4), triiodothyronine (T3), cholesterol and total lipid following the addition or withdrawal of the organophosphate, ronnel, from the diet. Steers were fed 0, 2, 4 and 8 mg ronnel/kg body weight daily in a Latin square arrangement of treatments with five 28-d periods. Plasma samples were obtained at -2, 1, 3, 5, 7, 9, 16 and 23 d of each period. Steers had not received ronnel before period 1 and, for periods 2 to 5, steers previously fed the lower levels (0 and 2 mg ronnel) were switched to the higher levels (4 and 8 mg ronnel) and steers previously fed the higher levels were switched to the lower levels. Treatment assignments for periods 1 and 5 were the same. Feed intake was similar for all treatments (7.8 kg/d) and daily gain was greater when ronnel was fed (.65 vs .88 kg). Plasma T4 concentrations increased positively in response to ronnel level within the first day after ronnel feeding began and reached a plateau within 3 d. Plasma T4 concentrations decreased following the withdrawal of ronnel, but the response was slower; a lower level being established within about 7 d. Changes in plasma T3 concentrations were small, but were concurrent with plasma T4 changes and were inversely related to ronnel level. Plasma cholesterol concentrations tended to be positively related to ronnel level, but changed slowly with time; plasma total lipid concentrations were not consistently affected by ronnel level. The results of this experiment demonstrate that ronnel has an immediate effect on thyroid function in beef steers.