Multiple transcription start sites for the GnRH gene in rhesus and cynomolgus monkeys: a non-human primate model for studying GnRH gene regulation

In humans, transcription of the gonadotropin-releasing hormone (GnRH) gene can be initiated at two transcription start sites to produce different GnRH mRNAs. The upstream transcription start site is used only in reproductive tissues and tumors. To determine if a similar pattern of GnRH gene expression exists in non-human primates, we cloned GnRH cDNA from rhesus monkey hypothalamic RNA using reverse transcriptase-polymerase chain reaction (RT-PCR) and the 5' flanking region of the monkey GnRH gene by PCR. A 96% similarity between monkey and human GnRH cDNA was found with 94% similarity in the upstream promoter region. An upstream transcriptional start site, was identified in cynomolgus monkey testicular mRNA, 504 base pairs upstream from the hypothalamic site, which was different from that identified in the human GnRH gene. Various cynomolgus monkey reproductive tissues were found to utilize this upstream transcriptional start site. In contrast, no evidence was found for the use of upstream transcriptional start sites in rat testis or placenta, suggesting that the reproductive tissue specificity of the upstream transcription start site may be a primate specific feature.

[Secretion of endothelin-1 by cultured human normal adrenal cells]

Endothelin (ET) is a vasoactive peptide produced by some other types of cells in addition to endothelial cells. The authors investigated into the possibility of ET-1 secretion by cultured human normal adrenal cells. Human normal adrenal cells were prepared by 2% collagenase digestion for 1.5 hours and cultured in DMEM supplemented with 10% FCS. Angiotensin I (10(-9)-10(-7) mol/L) was added to the experimental groups on the 7-9th days of cultivation. Mediums were collected after 24 hours and the levels of aldosterone, cortisol and ET-1 in the mediums were measured by RIA. Other than aldosterone and cortisol, ET-1 was detected in the cultured mediums of human normal adrenal cells. And the secretion of ET-1 was stimulated by angiotesin I. Therefore, it is proposed that ET-1 may play a role by autocrine or paracrine in the human normal adrenal gland.

Changes of plasma dynorphin levels before and after percutaneous balloon mitral commissurotomy in patients with mitral stenosis

Plasma dynorphin A1-13 levels were measured in 33 patients with mitral stenosis before and after percutaneous balloon mitral commissurotomy (PBMC). The results show that the basal levels of plasma dynorphin in blood from the antecubital vein in the patients were significantly higher than those in 31 healthy control subjects. The increase in circulating dynorphin closely correlated with the functional cardiac status and the presence of atrial fibrillation. Ten to fifteen minutes after PBMC, plasma dynorphin levels in blood from the femoral vein increased significantly. Seventy-two hours after the procedure, the levels of plasma dynorphin in blood from the antecubital vein had decreased significantly, but they did not decrease to the normal range. Plasma dynorphin levels in blood from the femoral vein were positively correlated with the mean left atrial pressure and the mean right atrial pressure before the first balloon inflation. Plasma dynorphin levels in blood from the antecubital vein were positively correlated with the heart rate and the mean transmitral pressure gradient, and negatively with the mitral valve area before and 72 hours after PBMC.

Changes of plasma beta-endorphin levels before and after percutaneous transvenous mitral commissurotomy in patients with mitral stenosis

To clarify the contribution of left atrial pressure to the secretion of beta-endorphin, we have investigated the relation between plasma beta-endorphin levels and hemodynamic changes in 35 patients with mitral stenosis undergoing percutaneous transvenous mitral commissurotomy (PTMC). Before PTMC, plasma beta-endorphin levels obtained from the antecubital vein (28.91 +/- 5.59 pg/ml) and from the femoral vein (28.20 +/- 5.44 pg/ml) in the patients with mitral stenosis were significantly higher than those obtained from the antecubital vein in the healthy volunteers (22.59 +/- 3.86 pg/ml, n = 34, P < 0.001 for each). The levels of beta-endorphin in the femoral vein correlated well with the mean left atrial pressure (r = 0.777, P < 0.001) and the mean right atrial pressure (r = 0.450, P < 0.01) before the procedure. The antecubital venous levels of beta-endorphin in patients in New York Heart Association functional Classes II (26.45 +/- 5.39 pg/ml, n = 20) and III (32.20 +/- 4.02 pg/ml, n = 15) were significantly higher than those in control subjects (P < 0.005 and P < 0.001, respectively). The differences between Classes II and III were significant (P < 0.001). The plasma levels of beta-endorphin in the patients complicated with atrial fibrillation were also significantly higher than those in patients with normal sinus rhythm (33.31 +/- 3.22 pg/ml, n = 13 vs 26.32 +/- 5.07 pg/ml, n = 22, P < 0.001). In ten to fifteen minutes after commissurotomy, plasma levels of beta-endorphin in the femoral vein significantly increased from 28.20 +/- 5.44 to 33.14 +/- 5.72 pg/ml (P < 0.001). In seventy-two hours after the procedure, plasma beta-endorphin levels in the antecubital vein fell to 24.37 +/- 2.59 pg/ml (P < 0.001 vs before PTMC and P < 0.05 vs control subjects). Plasma beta-endorphin levels in the patients with atrial fibrillation (26.62 +/- 2.36 pg/ml, P < 0.001 vs before PTMC and P < 0.002 vs control subjects) were still higher (P < 0.001) than those in patients with normal sinus rhythm (23.05 +/- 1.65 pg/ml, P < 0.001 vs before PTMC and P > 0.50 vs control subjects. There was a significant correlation between the levels of beta-endorphin in the antecubital vein and heart rate (r = 0.502, P < 0.001), mean transmitral pressure gradient (r = 0.543, P < 0.001) or mitral valve area (r = -0.710, P < 0.001) before and 72 hours after the procedure.

Fluorescence energy-transfer cyanine heterodimers with high affinity for double-stranded DNA. II. Applications to multiplex restriction fragment sizing

Energy-transfer cyanine dyes, a thiazsole orange-thiazole-indolenine (butylTOTIN) and a thiazole orange-thiazole blue heterodimer (pentylTOTAB), form high-affinity complexes with double-stranded (ds)DNA with donor fluorescence (lambdaF(max)527 nm) quenched >90% and with acceptor fluorescence emission above 650 nm (S. C. Benson, Z. Zeng, and A. N. Glaser (1995) Anal. Biochem. 231, 247-255). After separation by agarose gel electrophoresis, bands of precomplexed dsDNA-dye restriction fragments containing 10 pg of dsDNA are readily detected with a laser-excited confocal-fluorescence gel scanner (R. A. Mathies et al. (1994) Rev. Sci. Instrum. 65, 807-812) following donor excitation at 488 nm (argon ion laser) or direct acceptor excitation at 647 nm (krypton ion laser). Accurate two-color multiplex sizing of restriction fragments is obtained with 488-nm excitation with dsDNA fragments precomplexed with thiazole orange dimer (TOTO) as unknowns (detected at 500-565 nm, green channel) and dsDNA fragments stained with the energy-transfer cyanine dyes (detected at 645-750 nm, red channel) as internal standards. There is negligible cross talk of fluorescence between the red and green channels and no significant dye migration in mixtures of prelabeled standard and unknown fragments.

Fluorescence energy-transfer cyanine heterodimers with high affinity for double-stranded DNA. I. Synthesis and spectroscopic properties

We have designed, synthesized, and characterized fluorescent cyanine heterodimers that exploit resonance energy transfer to achieve strong emission above 650 nm with 488-nm excitation. Thiazole orange serves as the common fluorescence donor in these dyes and thiazole-indolenine, thiazole blue, or symmetric thiazole blue as acceptors. The donor and acceptor chromophores are linked by a polymethylene linker containing quaternary amino groups. These heterodimers have a high affinity for double-stranded DNA (dsDNA). The donor emission in the dsDNA-bound dyes is quenched by over 85%. The affinity for dsDNA and the quenching of donor fluorescence were optimized by varying the length of the linker between the donor and acceptor. Complexes of dsDNA fragments with such optimized dyes dissociated very slowly (t(0.5) > 300 min) during agarose gel electrophoresis.

Isolation, characterization, and chromosomal localization of mouse and human COUP-TF I and II genes

Chicken ovalbumin upstream promoter transcription factors (COUP-TFs) are orphan members of the steroid/thyroid hormone receptor superfamily. COUP-TF homologues have been cloned in many species, from Drosophila to human. The protein sequences of COUP-TFs are highly homologous across species, suggesting functional conservation. Two COUP-TF genes have been cloned from human, and their genomic organizations have been characterized. To determine whether the genomic organization is conserved between human and mouse, we isolated two mouse COUP-TF genes (I and II) and characterized their genomic structures. Both genes have relatively simple structures that are similar to those of their human counterparts. In addition, we mapped mouse COUP-TF I to the distal region of chromosome 13 and COUP-TF II to the central region of chromosome 7. Furthermore, we mapped human COUP-TF I to 5q14 of chromosome 5 and COUP-TF II to 15q26 of chromosome 15. The results demonstrate that COUP-TF genes are located in chromosomal regions that are syntenic between mouse and human.

Yama/CPP32 beta, a mammalian homolog of CED-3, is a CrmA-inhibitable protease that cleaves the death substrate poly(ADP-ribose) polymerase

Although the mechanism of mammalian apoptosis has not been elucidated, a protease of the CED-3/ICE family is anticipated to be a component of the death machinery. Several lines of evidence predict that this protease cleaves the death substrate poly(ADP-ribose) polymerase (PARP) to a specific 85 kDa form observed during apoptosis, is inhibitable by the CrmA protein, and is distinct from ICE. We cloned a ced-3/ICE-related gene, designated Yama, that encodes a protein identical to CPP32 beta. Purified Yama was a zymogen that, when activated, cleaved PARP to generate the 85 kDa apoptotic fragment. Cleavage of PARP by Yama was inhibited by CrmA but not by an inactive point mutant of CrmA. Furthermore, CrmA blocked cleavage of PARP in cells undergoing apoptosis. We propose that Yama may represent an effector component of the mammalian cell death pathway and suggest that CrmA blocks apoptosis by inhibiting Yama.

[Effect of tripchlorolide (T4) of Tripterygium wilfordii Hook on the production of endothelin-1 by endothelial cells of human umbilical vein]

Tripchlorolide (T4), a single active ingredient of Tripterygium wilfordii Hook was shown to possess both anti-inflammatory and immunosuppressive actions in experimental animals. The paper reports the effect of T4 on the production of endothelin-1 (ET-1) by endothelial cells of human umbilical vein. The cells were incubated with different doses of T4 (2.5, 5, 10 and 20 ng/ml) for 24 hours. By radioimmunoassay the results showed that T4 at concentration of 5 ng/ml significantly inhibited the production of ET-1 by endothelial cell in a dose dependent trend. The significance of T4 action was discussed.

[Effect of NG-nitro-L-arginine methylester on the secretion of endothelin-1 in vivo and in cultured endothelial cells]

We investigated the effect of nitric oxide, derived from L-arginine on the production of endothelin-1 in vivo and in cultured endothelial cells. In mechanically ventilated anesthetized dogs (n = 5), mean pulmonary arterial pressure (mPAP), pulmonary vascular resistance (PVR) and plasma endothelin-1 level of the femoral artery during hypoxic ventilation (FIO2 = 0.10) were 3.3 +/- 0.4kPa, 68.7 +/- 10.2kPa.s-1/L and 47.2 +/- 17.4ng/L respectively. NG-nitro-L-arginine methylester (L-NAME), an inhibitor of nitric oxide synthase, increased the peak value of mPAP and PVR during hypoxic ventilation to 4.9 +/- 0.6 kPa and 160.9 +/- 34.6kPa. s/L and its effect lasted for 3 hours. Meanwhile, plasma endothelin-1 level in the femoral artery was increased to 68.2 +/- 20.6, 72.8 +/- 20.9, 75.8 +/- 22.7 ng/L at 60, 120, 180 minutes respectively after the injection of L-NAME (P < 0.05 vs hypoxic control before the injection). In cultured endothelial cells from human umbilical veins, endothelin-1 level of culture medium increased significantly in 10(-11) and 10(-7) mol/L L-NAME group (n = 9, P < 0.05 vs control group). These findings indicate that endogenous nitric oxide is an inhibitory modulator of hypoxic pulmonary vasoconstriction and that nitric oxide inhibits the production of endothelin-1 in vivo and in cultured vascular endothelial cells.

Differential expression of protein kinase C isoforms in human colorectal cancers

Protein kinase C (PKC), a serine/threonine kinase central to signal transduction, is implicated in tumor promotion. At present, 10 PKC isoforms have been cloned but their precise tissue-specific role has yet to be defined. In order to determine if PKC is reduced in colorectal cancers (CRC) and if specific PKC isoforms are altered in different stages of human CRC progression, total RNA was extracted from human primary CRC, liver metastases, paired normal mucosa, and liver as well as CRC cell lines and examined for specific PKC isoform mRNA expression. PKC-alpha, beta II, delta, epsilon, eta(L), theta, and zeta were expressed in all tissues examined, while PKC-beta I was not detected. PKC-alpha, beta II, delta, epsilon, and zeta were decreased in most primary CRC. However, the reduction in PKC-beta II was greatest in advanced primary CRC (P < 0.05). Although PKC-gamma was detected in about 29.6% of primary CRC and liver metastases, it was absent from all corresponding normal tissue. In addition, a second band hybridizing to our PKC-gamma probe was uniquely present only in cancerous tissue and not in brain control, suggestive of alternative splicing. PKC-alpha, delta, epsilon, and zeta were present in all cell lines. PKC-beta I/II were both uniformly absent from all cell lines. Since mRNA expression for most PKC isoforms is decreased in CRC, the previously reported decreases in overall PKC activity in CRC are not solely due to a post-translational enzyme modification.(ABSTRACT TRUNCATED AT 250 WORDS)

[The effect of acute pulmonary alveolar hypoxia on canine plasma endothelin-1 levels]

The effect of acute pulmonary alveolar hypoxia on plasma endothelin (ET)-1 levels was observed in 10 anesthetized dogs (hypoxic group). Plasma ET-1 like immunoreactivity (-LI) levels increased significantly at the fifth, fifteenth, sixtieth minute after hypoxia (fractional inspiratory O2 concentration 10%), but they had no remarkable change at the thirtieth minute. It was suggested that the first peak of ET-1-LI levels (the fifth minute) might be caused by the release of endothelin-1 which was formed before hypoxia and the second peak could be associated with the secretion of ET-1 after hypoxia. The effect of ligustrazine on plasma ET-1-LI levels during hypoxia was also investigated in other 8 anesthetized dogs. Plasma ET-1-LI levels reduced significantly at the fifth minute after the injection of ligustrazine, compared with the hypoxic group. The result demonstrated that ligustrazine can inhibit the release of ET-1, which could be correlated with the blockade of calcium channel caused by ligustrazine.

[Morphometric study of motor cortex in acute focal epilepsy rat induced by coriaria lactone]

Twenty adult male Wistar rats were divided randomly into two groups (10 rats for LM, 10 rats for EM). The experimental rats were injected with convulsive dosage 3.8 microliters (19 micrograms) of coriaria lactone (CL) in the left cerebral motor cortex of the fore limb to induce acute focal epilepsy. The control rats were injected with normal saline of the same volume and at the same location. Motor cortex was cut coronally 2 hours after seizure and the layer V was studied morphometrically. Under x400 and x7000, take photos of focus, parafocus areas respectively for morphometric study. The number of neurons and neuroglias of layer V was counted in the LM photos. The number of presynaptic terminals of the neuropil was counted in the x7000 EM photos and the area fraction of each constitute in the neuropil was measured. The positive results demonstrated that the number of neurons and neuroglias in the focus and parafocus areas of the experimental animals was significantly lower than that in the control group, the side injected was lower than the other side and it was the lowest in the focus. The number and area fraction of the presynaptic terminals of the experimental rats at the focus neuropil decreased significantly, but the area fraction of neuroglial components increased significantly. The authors suggest that the convulsive dosage of CL may have toxic effect on some neurons and neuroglias and therefore to decrease the number of both types of cells and the number and area fraction of presynaptic terminals in the neuropil.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of potential ligands for nuclear receptors in cellular extracts

In response to external stimuli, steroid receptors are directly influenced to transactivate gene expression. Assuming they exist, identification of ligands for orphan steroid receptors is a key to understanding their physiology. In the orphan subgroup of the steroid receptor superfamily, the putative carboxyl terminal ligand-binding domain (LBD) is well conserved among members of the superfamily, which suggests a role in ligand binding. A consequence of ligand binding is the induction of a significant conformational change within the LBD which is necessary for the transactivation function. This characteristic conformational change can be detected by partial proteolytic digestion and has been localized by mutational analysis and epitopic mapping of the LBD using monoclonal antibodies. Based on this finding, a sensitive in vitro assay was developed for the rapid screening and identification of potential ligands for orphan receptors. We examined the patterns of conformational changes in the androgen receptor, glucocorticoid receptor, and progesterone receptor induced by binding of their cognate agonists and antagonists. We demonstrated that the conformational changes induced by ligands can serve as characteristic and reliable markers to distinguish between the ligand-bound and apoprotein states of a receptor. The sensitivity and feasibility of employing this assay to detect new endogenous ligands using fractionated cellular extracts were also tested. The results strongly suggest that unknown compounds can be defined as potential ligands for orphan receptors using this approach.

[Synthesis of terephthalic acid derivatives and their activity on human promyelocytic leukaemia cells HL-60]

There were 13 derivatives of terephthalic acid were synthesized, in which 9 compounds were not found in literature. The 9 compounds were evaluated for their differentiation-inducing activities on human promyelocytic leukaemia cells HL-60. Compounds N1 and N4 possessed potential activity. Their percentage of differentiating effect was 55% (5 x 10(-6) mol/L), but it was less than that of retinoic acid (79%, 10(-7) mol/L).

[The effect of interleukin-2, interleukin-4 and tumor necrosis factor on LAK cells activity]

We studied the effect of single or combination of interleukin-2 (IL-2), interleukin-4 (IL-4) and tumor necrosis factor (TNF) on lymphokine-activated killer cells (LAK) activity which killed both of target cells HepG2 and 2 2,1,5 cells induced for seven days. It was shown that LAK activity induced by the combination of triplet of IL-2, IL-4 and TNF was higher than that induced by single or two of IL-2, IL-4 and TNF, and that enhanced LAK activity was associated with the quantity of IL-2 receptor expression and lysosomes of LAK precursors.

No association between alleles or genotypes at the dopamine transporter gene and schizophrenia

The dopamine transporter gene (DAT1) is an important candidate gene for schizophrenia. A 40-bp VNTR (variable number of tandem repeats) polymorphism of DAT1 has been typed in 105 schizophrenic patients and 98 normal control subjects from Sichuan (China). Compared with allele frequencies for Caucasians reported in the literature, the Chinese population investigated showed a reduced frequency of the 9-copy allele and an increased frequency of the 10-copy allele. The observed frequency of genotypes was in agreement with the expected values according to Hardy-Weinberg equilibrium. No significant difference was found between patients and control subjects with regard to allele frequency, allele prevalence, and genotype counts. The results of the association study presented here are in agreement with the negative results of linkage analyses in schizophrenia pedigrees from Iceland (Kristbjarnarson et al., submitted) and from Utah (Byerley et al., 1993). Taken together, these studies suggest that variation in the dopamine transporter gene (DAT1) is unlikely to be a factor in the etiology of schizophrenia. The observed differences in allele frequencies between Chinese and Caucasian groups suggest that the human transporter gene might be useful for the construction of evolutionary trees in humans and primates as illustrated by Cavalli-Sforza's work (Mountain et al., 1992).

[Synthesis of p-substituted benzoylaminobenzoic acid (methyl esters) and its differentiation induction in activities of human promyelocytic leukemia cells HL-60]

Sixteen p-substituted benzoylaminobenzoic acids and their methyl esters were synthesized, of which nine were not found in literature. All of the topic compounds were evaluated for their differentiation induction in activities of human promyelotic leukemia cells HL-60. Compounds III1, III2, III4, and III5 possessed potential activities. The differentiation rate, of III4 and III5 was 70% respectively. But it was less than that of retinoic acid (97%).

[Quantitative study on cerebral motor cortex structure of kindling rat induced by coriaria lactone]

Ten male Wistar rats were divided into two groups. The experimental rats were injected with subconvulsive dosage of coriaria lactone (1 mg/kg) intramuscularly every 3.5 days to induce kindling seizures. The controls were injected with normal saline. Cerebral motor cortex of kindling rats was taken at the time between seizures and layer V was compared morphologically with that of the control. The number of neurons and neuroglias was counted from light micrographs. The numerical density and length fraction of boutons on the surface of pyramidal somata were measured from electron micrographs with MIAS 300 type image analyser. The number of synapses in neuropil was counted directly and the areal fraction of various constitute in neuropil was measured stereologically from EM photos. In the experimental rats, the number of neurons remained unchanged and the numerical density and length fraction of boutons on the surface of pyramidal somata showed no change, either. The number of synapses (or presynaptic terminals) decreased significantly in neuropil, but the areal fraction of synaptic terminals had no change and the areal fraction of dendrites and unmyelinated fibers decreased. The areal fraction of myelinated fibers increased significantly. The number of neuroglias and the areal fraction of neuroglial processes increased significantly in the experimental rats. The data suggest that the major morphological changes are manifested as a decline in the pyramidal dendritic components, especially dendritic spines, and the axons with its terminals from superficial neurons in motor cortex layer V of the kindling rats induced by coriaria lactone, besides the neurogliosis which is similar to that occurring in other long-term seizures.

Usefulness of carcinoembryonic antigen monitoring despite normal preoperative values in node-positive colon cancer patients

PURPOSE

The aim of our study was to determine to what extent serial carcinoembryonic antigen (CEA) monitoring is helpful in detecting colorectal cancer recurrence in patients if their preoperative serum CEA is normal. Additional major objectives of this study were to correlate CEA immunohistochemical features of the primary tumor with serum CEA levels at the time of tumor recurrence in node-positive colorectal cancer patients with low preoperative CEA values.

METHODS

One hundred fourteen node-positive colorectal cancer patients with preoperative serum CEA levels of < 5.0 ng/ml undergoing clinically curative operations were studied. Primary tumors were evaluated for tissue CEA using the same monoclonal antibody as used for serum CEA determinations utilizing the avidin-biotin-peroxidase immunohistochemical technique.

RESULTS

The exact preoperative serum CEA value did not correlate with tumor grade, immunohistochemical CEA intensity or pattern. In the 32 patients who developed recurrent cancer, the serum CEA at recurrence was greater than 5 ng/ml in 44 percent. All such patients had CEA present in their primary tumor. There was no correlation with the exact preoperative serum CEA, the intensity of the primary tissue CEA, or the localization of such CEA and subsequent serum elevation at recurrence.

CONCLUSION

Serum CEA is a useful marker in the detection of recurrent colorectal cancer despite normal preoperative values.