[Synthesis of delta virus cDNA of China Sichuan strain]

delta virus cDNA of China Sichuan strain, 1.2 kb in length, was synthesized by extraction of RNA from liver tissue in a patient with subacute severe hepatitis, followed by reverse transcription and polymerase chain reaction (RT-PCR). The result was confirmed by Southern blot hybridization using 32P and biotin labelled delta virus cDNA (HN88, cloned in USA) probes respectively.

Cardiac mechanical restitution in active and hibernating Richardson's ground squirrel

The cardiac mechanical restitution was compared in papillary muscles between the active and the hibernating Richardson's ground squirrels at 0.1, 2.8, and 5 mM external Ca2+ concentration [( Ca2+]o). The amplitude of the restitution was significantly higher in hibernating animals between 37 and 7 degrees C at all [Ca2+]o. The first postrest contraction (F1) was highest at 20 degrees C and lower at 37 and 7 degrees C in both groups. The pause duration for maximum F1 was 30 s in active but 10 s in hibernating animals at 37 degrees C and increased to 100 s in both groups at 7 degrees C. The postrest potentiation was eliminated by 10(-6) M ryanodine at 20 degrees C in both groups, and this inhibitory effect was more pronounced in the hibernating group. Together, our results suggest that the activator Ca2+ for excitation-contraction coupling is mainly derived from the sarcoplasmic reticulum (SR) pool in both active and hibernating ground squirrel, and the dependence on SR Ca2+ release via ryanodine-sensitive Ca2+ channels is more marked in the hibernating state. Furthermore, there is no significant difference in sensitivity of the cardiac mechanical restitution to [Ca2+]o between the active and the hibernating condition.

[Purification and immunological behavior of beta-lactamase from Bacteroides fragilis]

The beta-lactamase crude extract of Bacteroides fragilis 55 was chromatographed with DEAE-sepharose CL-6B and sephadex G-100. The partial purified enzyme proteins was further purified by cutting the band on PAGE in which the beta-lactamase was distinguishable from other proteins by our method of fluorescent staining. Using purified preparations to be mixed with liposome-CPS-K, prepared specific antisera against the purified beta-lactamase. Serological reactions were carried out by IgG-ELISA together with western blotting. The results revealed that Bacteroides fragilis beta-lactamase possessed its species-specificity.

A cis-acting element in the major immediate-early (IE) promoter of human cytomegalovirus is required for negative regulation by IE2

The major immediate-early promoter (MIEP) of human cytomegalovirus (CMV) contains a number of different enhancer elements in both repetitive and nonrepetitive sequences that influence the level of downstream transcription. This report describes a cis-acting element in the MIEP that responds to negative regulation by the IE2 gene product. Deletion analysis demonstrated that the cis-acting repressor element is located between the TATA box and the transcription initiation site from -13 to -1. The DNA sequence of the repressor element is 5'-CGTTTAGTGAACC-3'. The sequence is found in both the human and simian CMV MIEPs but not the murine CMV MIEP or in several other enhancer-containing promoters. The repressor element was isolated in a DNA fragment from -13 to +3 and was found to be functional in either orientation. It could be transferred to a heterologous enhancer-containing promoter and was functional when placed between the TATA box and the transcription initiation site. The element did not function when placed downstream of the transcription initiation site. Therefore, the cis-acting repressor element is position dependent. The role of the repressor element and the IE2 gene product in human CMV productive or latent infection is discussed.

Temperature effects on the Na and Ca currents in rat and hedgehog ventricular muscle

Cardiac transmembrane potentials and Na and Ca currents were recorded at different temperatures in rat and hedgehog ventricular muscle. At 35 degrees C in both species resting potential was about -80 mV and upstroke velocity (Vmax) of the action potential above 100 V/s. The shape of the action potential in hedgehog ventricular cells at 35 degrees C was similar to that in the rat showing a fast repolarization phase. When temperature was decreased, the membrane resting potential depolarized and action potential amplitude and Vmax declined. In rat ventricular cells at 10 degrees C, the resting potential was about -40 to -50 mV and Vmax was reduced to about 5 V/s. In hedgehog ventricular cells, however, the transmembrane potentials and Vmax were better maintained at low temperature. Phase 3 of the action potential was markedly prolonged below 20 degrees C in hedgehog but not in rat ventricular cells. When temperature was decreased to 10 degrees C the availability curve of the Na current shifted toward more negative potentials and ICa.peak declined in rat ventricular cells. In hedgehog cardiac preparations, the Na current was less influenced by the cooling and ICa.peak did not change very much at low temperatures. A transient inward current usually considered to induce cardiac arrhythmias could be recorded in rat ventricular cells below 20 degrees C but not in hedgehog preparations. These features of hedgehog cardiac membranes may contribute to the cold tolerance and the resistance to ventricular fibrillation during the hypothermia in mammalian hibernators.

Colchicine-induced increases in immunoreactive neuropeptide levels in hypothalamus: use as an index of biosynthesis

The colchicine-induced accumulation of vasopressin (AVP) and oxytocin (OXT) has recently been applied to estimate the synthesis and turnover rates for these neuropeptides in whole rat hypothalamus. In the present studies, this pharmacologic procedure has been examined as a potential method for estimating hypothalamic somatostatin (SRIF) synthesis rate, and evaluated further for its utility in estimating nonapeptide synthesis in individual hypothalamic nuclei. Adult male rats received a single injection of colchicine (8 micrograms) into the third ventricle under pentobarbital anesthesia. Twenty-four hr later, immunoreactive (IR) levels of AVP and OXT increased considerably, as previously noted. Hypothalamic IR-SRIF levels, however, were unaffected. The absolute increases in IR-AVP and IR-OXT were greatest in the supraoptic nucleus (SON), with smaller increments in the para/periventricular hypothalamus (PVH) and the median eminence (ME). IR-SRIF levels showed no changes in the PVH or the ME. As a test, the method was applied to the detection of changes in AVP synthesis in diabetic rats. The colchicine procedure reported increases in AVP synthesis in both the SON and PVH in diabetic animals, a result compatible with that obtained previously for whole hypothalamus using radiolabeled procedures. Together, the results indicate that the colchicine procedure is useful in detecting changes in the syntheses of some (AVP and OXT) but not all (SRIF) neuropeptides, and that when applicable, the method is sufficiently sensitive to detect changes in small hypothalamic regions. The method may prove useful in estimating changes in peptide synthesis analogous to that used for serotonin and dopamine; e.g., 5-hydroxytryptophan and dopa accumulation following inhibition of aromatic L-amino acid decarboxylase.

Nonstationary filtering of transmission tomograms in high photon counting noise

The algorithm presented here for nonstationary constrained least-squares filtering deals with the transmission photon counting noise problem in the presence of limited dosages and highly nonhomogeneous fields. This technique consists of a design for a set of nonstationary filters, tuned to local noise autocorrelation functions in the reconstructed image. Estimates of noise properties can be taken from object detection information. The approach yields improvement in the tradeoff between noise levels and resolution of the image by exchanging artifacts for less colored noise, which is more easily overcome by the viewer.

Effect of low temperature on the cytosolic free Ca2+ in rat ventricular myocytes

The effect of low temperature on the cytosolic free Ca2+ [( Ca2+]i) has been investigated in isolated ventricular myocytes from adult rats using the fluorescent probe Indo-1. The distribution of Indo-1 between the mitochondrial and cytoplasmic compartments was first determined in the isolated myocytes using the digitonin and Triton X-100 treatments. By subtracting the mitochondrial [Ca2+]i from the total [Ca2+]i measured with Indo-1, the average cytosolic [Ca2+]i was found to increase significantly (P less than 0.05) from 139 nM to 255 and 297 nM when the temperature was decreased from 37 degrees C to 15 degrees and 5 degrees C, respectively. A marked increase in cytosolic [Ca2+]i to a new steady state level was observed when the membrane of myocytes was depolarized by 60 mM KCI; the average magnitude of increase being 110, 243 and 186 nM, at 37 degrees, 15 degrees and 5 degrees C respectively. Our results support the hypothesis that the cardiac arrhythmia typically observed in the hypothermic rat is due to an increased cytosolic [Ca2+]i with decreasing body temperature.

Blood cell rheological changes during prolonged perfusion with membrane oxygenation (PPMO) using perfluorochemicals

The aim of this study was to discover the effect of the perfluorochemical FC-43 on blood cell rheology during experimental prolonged perfusion with membrane oxygenation (PPMO). Using fresh human blood from healthy donors, six experiments with FC-43 in one clinical dose of 30ml/kg, another six with a dose of 1 0ml/kg, and 16 controls were pumped for 72 hours in a perfusion system containing an oxygenator similar to an extracorporeal membrane oxygenation circuit. Blood trauma was analysed using the St George's Filtrometer by estimating blood cell filtrability, clogging particles and clogging rate; the latter two reflecting blood cell aggregability. At 72 hours the filtrability of red cells was reduced by over 95% and 7.0% in the FC-43 groups and controls respectively; the FC-43 groups showed significantly (p < 0.01) greater reductions during perfusion. Both FC-43 concentrations increased the rheological damage to white cells from the outset. The white cells showed a greater tendency to clog than the red cells, suggesting an increased aggregability during prolonged perfusion. The 30ml/kg FC-43 dose induced relatively more damage than the doses in the other groups. This study suggests that FC-43 increased blood cell damage during PPMO in a dose-related manner, and that FC-43 during PPMO should preferably be made less toxic if it is to be used routinely as a blood substitute for prolonged extracorporeal circulation.

Mechanical restitution at different temperatures in papillary muscles from rabbit, rat, and hedgehog

Mechanical restitution curves, i.e., peak isometric force as a function of the duration of the preceding test interval, were investigated in papillary muscles from rabbit, rat, and hedgehog. Peak force of rabbit papillary muscle increased with prolongation of the test interval from about 0.3 s to about 1.0 s and for longer intervals peak force declined (called type I mechanical restitution). On the other hand, in rat and hedgehog, papillary muscles' force reached a maximum value at intervals of 30-120 s (called type II mechanical restitution). When temperature was decreased from 35 to 15 degrees C, maximum force of type I mechanical restitution shifted from 1.0 to 10 s, whereas maximum force of type II restitution did not change significantly. Type II mechanical restitution consisted of two different phases, designated phase A and phase B, respectively. As temperature was decreased from 35 to 0 degree C in the hedgehog preparation, the two phases became even more separated. At 35 degrees C, the rising part of mechanical restitution in the rabbit muscle could not be distinguished from phase A of the hedgehog preparation and was also very similar to phase A of the rat muscle. Phase A is thus present in both type I and type II mechanical restitution, but phase B is a special feature of type II mechanical restitution. Phase A and phase B might be a manifestation of activator calcium originating from two different sources, e.g., the sarcoplasmic reticulum and the sarcolemma.

[Tongue tip microcirculation in patients with different symptoms]

Observations of tongue tip microcirculation were made on 104 patients with different symptom-complex [5 groups: Yin deficiency, Yang deficiency, Qi.blood deficiency, Qi stagnation-blood stasis, damp-heat] in view of TCM, and on 100 healthy persons. 10 indicators including the transverse diameter of the fungiform papillae, morphology of microvascular clumps in the tongue papillae, congestion of the top of microvascular loop, loop dilation, blood color, hemodynamics in microvascular loop, exudation, hemorrhage and loop morphology were observed. The results were: patients of each group were found to have to different degree microcirculation dysfunction; every group differed with Qi stagnation-blood stasis group of being most different. The numbers of abnormal indicators: Qi stagnation-blood stasis group had all 10; Yang deficiency group 9; Yin deficiency and Qi-blood deficiency group 8, 8 respectively; damp-heat group 7. This study discussed the relationship between tongue tip microcirculation of each group and the changes of tongue picture and typing of differentiation of symptoms and signs in view of TCM.

Effects of low temperature on contraction in papillary muscles from rabbit, rat, and hedgehog

During hibernation the body temperature may fall to only a few degrees above 0 degree C. The heart of the hedgehog continues to function whereas the hearts of nonhibernating mammals stop beating. The present study was performed to investigate and compare the mechanical responses to hypothermia in rabbits, rats, and hedgehogs. Isometric force was recorded from papillary muscles mounted in an organ bath and effects of hypothermia on the mechanical restitution curve were also compared. A reduction of bath temperature from 35 degrees C caused an increase in peak developed force. Maximum force was seen at 20 degrees C in the rabbit, 15 degrees C in the rat, and 10 degrees C in the hedgehog preparations. In all the species there was a similar prolongation of time to peak force and of time from peak to half-relaxation as temperature was lowered. An increase in resting force and after-contractions were recorded in the rabbit and rat muscles at temperatures below 15 and 10 degrees C, respectively. The rabbit and rat preparations became inexcitable at temperatures below 10 and 5 degrees C, respectively. The hedgehog papillary muscle, on the other hand, still contracted at 0 degree C and did not show increased resting force nor after-contractions. The results are consistent with the hypothesis that there is a calcium overload in cardiac cells from rabbit and rat at low temperatures but there is no calcium overload in the hedgehog muscle during hypothermia.

[Screening and identification of apolipoprotein CIII cDNA clones from human liver cDNA library and preparation of apolipoprotein CIII cDNA probe from the clones]

Four of positive clones were obtained by three runs of screening the cDNA library of human liver with rabbit antihuman apolipoprotein (apo) CIII IgG. One of them was identified to be the positive clone of apoC III cDNA by restriction endonuclease map studies of the cDNA insert fragment and by Western blot analysis of the expression products. The apoCIII cDNA-gamma gt11 recombinant DNA prepared from the positive clone can be used in RNA-dot blot analysis as apoCIII cDNA probe. And the apoCIII cDNA clone can be also used to produced apoCIII peptide under the induction of isopropyl-beta-D-thiogalactoside. The apoCIII peptide, after purification, has a lot of use in further studies.

[Effects of high carbohydrate and high fat diet on plasma apolipoproteins AI, AII, B100, CI, CII, CIII and E in normal and hypertriglyceridemic humans]

Effects of high carbohydrate (CHO) and high fat diet on plasma apolipoproteins (apo) AI, AII, B100, CI, CII, CIII and E were assessed in 10 healthy subjects and 10 patients with endogenous hypertriglyceridemia. High CHO diet consisted of 80% CHO, 5% fat and 15% protein of total calories, and high fat diet consisted of 40% CHO, 45% fat and 15% protein. After 5 days normal diet (60% of total calories from CHO, 25% from from fat and 15% from protein), the subjects studied received sequentially high CHO diet and normal diet for 5 days and high fat diet and normal diet for 5 days. Fasting blood samples were drawn on days 1, 3, and 5 of high CHO and high fat diet period, and 5 days after taking normal diet. Results showed that fasting plasma apo AI slightly decreased (P less than 0.01) on day 3 of the high CHO diet period and slightly increased (P less than 0.01) on day 3 of the high fat diet period, plasma apo AII increased after intake of high CHO diet, but no changes were observed after the subjects were placed on high fat diet. Fasting plasma apo B100 decreased (P less than 0.001) in hypertriglyceridemics on the 3rd day of the high CHO diet, but no differences were noted in normal subjects on the same diet. On the 3rd day of the high fat diet period, apo B100 increased (P less than 0.01) in normal subjects, but no changes were found in hypertriglyceridemics. Apo CII and CIII levels declined during the high CHO diet period but increased in normal subjects after intake of high fat died.(ABSTRACT TRUNCATED AT 250 WORDS)

Crystallization and preliminary X-ray diffraction studies of the engrailed homeodomain and of an engrailed homeodomain/DNA complex

The homeodomain from the engrailed protein of Drosophila has been crystallized from ammonium phosphate at pH 6.8. The crystals form in space group P6(1)22 (or P6(5)22), with cell dimensions a = b = 44.8 A and c = 118.2 A. These crystals diffract to 1.8 A resolution. A complex containing the engrailed homeodomain and a duplex DNA site also has been crystallized. The cocrystals form in space group C2 with a = 131.2 A, b = 45.5 A, c = 72.9 A and beta = 119.0 degrees. These crystals diffract to 2.6 A resolution.

[Effect of high carbohydrate and high fat diets on plasma glucose, insulin and lipids in normal and hypertriglyceridemic subjects]

The fasting plasma glucose, insulin and lipids response to high-carbohydrate-low-fat diets and low-carbohydrate-high-fat diets in normal subjects and patients with endogenous hypertriglyceridemia was observed. The normal, high carbohydrate and high fat diets consisted of 60%, 80% and 40% carbohydrate, 25%, 5% and 45% fat and 15% protein of total calorie respectively. The fasting plasma glucose levels increased (P less than 0.01) on day 1, insulin increased on day 3 (P less than 0.01 and P less than 0.05) and TG levels increased on days 3 and 5 after taking high carbohydrate diets both in the normal and hypertriglyceridemic groups. The fasting plasma TC and HDL-C decreased on high carbohydrate diets mainly in the hypertriglyceridemic group. The fasting plasma glucose slightly decreased on day 5, TG decreased on day 1 (P less than 0.05) and TC increased on day 1 and 3 (P less than 0.01) after taking high fat diets, but no differences were observed in insulin levels. Fasting plasma HDL-C levels in the normal group remained unchanged, but significantly decreased 3 days after taking high fat diets in the hypertriglyceridemic group (P less than 0.001). Our results indicate that high carbohydrate intake may be an important cause of hypertriglyceridemia in our country. This diet may cause a slight increase in the blood glucose level, which in turn stimulates an increase in plasma lipids and decrease in HDL-C, which is associated with an increase in the incident of coronary heart disease.(ABSTRACT TRUNCATED AT 250 WORDS)

[Quantification of human serum apolipoprotein A II by radial immunodiffusion]

A radial immunodiffusion assay (RID) for human serum apolipoprotein A II (apo A II) was developed. Antisera to human apoA II were raised in goats with purified apoA II. The antibody-gel plate was prepared with 1% agarose. 5 microliters of each sample was added in a well. Diffusion was performed at 25 degrees C for 48 h. The minimum measurable concentration of apoA II was 58ng. The standard curve with a working range of 17.3-69 mg/dl was plotted. The coefficients of variation of within and between plates were 1.5-4.6% and 5.6% respectively. The recovery of the assay was 90.3-102.0%. The concentrations of apoA II for healthy men and women in Chengdu area were 26.7 +/- 4.4 mg/dl (n = 45) and 26.6 +/- 4.6 mg/dl (n = 31) respectively.

[Quality of retrospective survey of deaths and its evaluation]

An imitative retrospective survey (RS) of deaths was carried out to evaluate the errors and quality of the retrospective survey by using the data on Qidong Death-Cause Registry. Results showed that the agreement rates for death-cause, death-age and death-date of RS were 79.69%, 67.97% and 58.98%, respectively. The total agreement rate for the three items was 31.95%, in which 52.71% in liver cancer, 25.00%, other cancers, 21.05%, other diseases, and 26.32%, accidents. Because some of the errors were cancelled out each other, the mis-report rates for the above diseases were 4.65%, 15.63%, 14.47%, and 10.53%, respectively, and the statistical breakdown of data, age-group and death-time distributions met basically with the data on registration (P greater than 0.05). This study indicates that the errors of the data from RS are rather higher compared with data on registration, yet the data on the whole can reflect the population distribution, time trends and epidemic intensity of diseases investigated, RS might be considered as a mean of getting historical data, but its application and evaluation should be cautious.

The growth of human fibroblasts and A431 epidermoid carcinoma cells on gamma-irradiated human amnion collagen substrata

Human fibroblasts and A431 human epidermoid carcinoma cells were cultured on gamma-irradiated human amnion collagen as well as on plastic dishes and non-irradiated collagen coated dishes. The morphology, attachment, growth and short-term cytotoxicity of these culture conditions have been determined. Both irradiated and non-irradiated amnion collagen enhanced the attachment and proliferation of fibroblasts as compared to the plastic dishes. No differences in these properties were observed for A431 cells cultured on irradiated collagen when compared with culture on non-irradiated collagen substrates. Cytotoxicity assays showed that irradiated and non-irradiated collagens were not cytotoxic for either fibroblasts or A431 cells. The results demonstrated that amnion collagen irradiated at doses of 0.25-2.0 Mrads is optimal for cell growth.

Immune response to gamma-irradiated injectable human amnion and human skin collagens in the rat

The immune response in rats to gamma-irradiated human amnion and human skin collagen was characterized through histologic and immunologic methods. Pepsin-extracted human amnion collagen and skin collagen were purified and reconstituted. Implants of amnion collagen demonstrated greater persistence than skin collagen. For amnion collagen implants, no significant inflammatory response was found. Fibroblast and adipocyte ingrowth and neovascularization were present. Conversely, obvious inflammatory infiltration was evident in the skin collagen implants. Enzyme-linked immunosorbent assay results showed that anti-amnion collagen antibody levels were significantly lower than anti-skin collagen antibody levels against their respective implant materials. The ratios of type I to type III collagen are 56:44 and 95:5 for amnion collagen and skin collagen, respectively. These findings suggest that in this heterologous type system, type III collagen-rich amnion collagen preparations appear superior to skin collagen for soft-tissue augmentation.

[Changes in platelet aggregation and coronary collateral circulation during the early phase of myocardial ischemia in dogs]

Experiments were performed on 18 anesthetized open-chest dogs to observe the changes in platelet aggregation and coronary collateral circulation during the early phase of acute myocardial ischemia. An increase in platelet aggregation rates (PAgR) and a decrease in platelet counts (PC) were found in the blood collected from the ischemic myocardium after coronary occlusion. PAgR was increased by 58.7 +/- 5.6% and PC was reduced by 39.5 +/- 23.6% at 50 min after occlusion (P less than 0.01). Under the condition of controlling aortic blood pressure, collateral coronary vascular capacity (CVC) was not changed (P greater than 0.05), but the effective collateral coronary flow to the ischemic zone, calculated by Wyatt et al's equation, was significantly reduced by 23.5 +/- 9.7% at 50 min after occlusion (P less than 0.05). There was a negative correlation between the changes in PAgR and the effective collateral coronary flow ( r = -0.857, P less than 0.01), and between the collateral indices and infarct size (r = -0.847, P less than 0.01). Abnormal changes in parameters of platelet and coronary collateral circulation after myocardial ischemia were nearly abolished by intravenous injection of aspirin before coronary occlusion. The results suggest that the deleterious changes of platelet aggregation during the early phase of the acute myocardial ischemia may decrease the effective collateral coronary flow significantly and thereby enlarge the infarct size.

The promoter-regulatory region of the major immediate-early gene of human cytomegalovirus responds to T-lymphocyte stimulation and contains functional cyclic AMP-response elements

Prior studies have demonstrated that a small proportion of blood lymphocytes from patients with human cytomegalovirus (HCMV) infection express only the viral immediate-early (IE) genes (L. Einhorn and A. Ost, J. Infect. Dis. 149:207-214, 1984; G. P. A. Rice, R. D. Schrier, and M. B. A. Oldstone, Proc. Natl. Acad. Sci. USA 81:6134-6138, 1984). The present studies demonstrate that the IE genes of HCMV are transcribed in Jurkat cells (T lymphocytes) only after activation of the cells with mitogens. Transcription of the IE genes is from an upstream enhancer promoter-regulatory region containing several different repeated sequence motifs. Chimeric plasmids were constructed with just a single copy or three copies of a synthetic oligonucleotide sequence of either the 16-, 18-, 19-, or 21-base-pair (bp) repeat elements upstream of the minimal wild-type promoter sequence to drive expression of the indicator gene, chloramphenicol acetyltransferase (CAT). The 18- or 19-bp motifs in the enhancer region were found to be important in mediating the effect of the mitogens. However, the CAT activity detected with the 19-bp repeat was always significantly higher than that found with the 18-bp repeat. There was an additive effect by multiple copies of the 18- or 19-bp repeat sequences on gene expression. The 19-bp repeat contains a sequence identical to that described for a cyclic AMP (cAMP) response element, and plasmids containing only this sequence and the minimal promoter sequences upstream of the CAT gene respond to agents which increase intracellular cAMP. Functional cAMP response elements are present in the wild-type promoter-regulatory region and are associated with the 19-bp repeat sequences. It is proposed that activation of lymphocytes results in expression of the IE genes of HCMV, in part via the activation of cellular trans-acting factors which interact with the 18- and 19-bp motifs in the HCMV IE promoter-regulatory region. The 19-bp repeat is the major contributor to the strength of this enhancer-containing promoter-regulatory region.

Topographical characterization of the domain structure of the bovine adrenal atrial natriuretic factor R1 receptor

We have studied the structure and function of the membrane atrial natriuretic factor R1 (ANF-R1) receptor using limited proteolysis and exoglycosidase treatment. Limited digestion with trypsin of the receptor from bovine adrenal zona glomerulosa membranes resulted in the conversion of the native 130-kDa receptor into a single membrane-associated ANF-binding proteolytic fragment of 70 kDa. The 70-kDa fragment bound ANF with enhanced binding affinity but retained intact ANF-R1 pharmacological specificity and was still sensitive to modulation by amiloride. Trypsin treatment of the membranes produced a dual effect on ANF binding. Low concentrations of trypsin (less than or equal to 25 micrograms/mg of protein) increased ANF binding while higher concentrations dose dependently reduced the binding of the hormone. The increase of ANF-binding activity was associated with the formation of the 70-kDa fragment while the loss of ANF binding paralleled the degradation of the 70-kDa fragment. Low concentrations of trypsin drastically decreased the ANF-sensitive guanylate cyclase activity of the membrane fraction. This loss of catalytic activity strongly correlated with the formation of the 70-kDa tryptic fragment. We also evaluated the effect of ANF binding on the susceptibility of the receptor to proteolytic cleavage. The occupied receptor exhibited a greater sensitivity to trypsin digestion than the unoccupied protein, consistent with the hypothesis that hormone binding induces an important conformational change in the receptor structure. On the other hand, the 70-kDa fragment was much more resistant to proteolysis when occupied by ANF, suggesting that the ANF-binding domain forms a very compact structure.(ABSTRACT TRUNCATED AT 250 WORDS)

N alpha-acetyl-[Arg8]vasopressin antagonizes the behavioral effect of [Cyt6]vasopressin-(5-9), but not of vasopressin

It has been found recently that N alpha-acetyl-[Arg8]vasopressin (Ac-VP) is present in the brain of rats. The physiological significance of this peptide is as yet unknown. Therefore, the central nervous system effects of this peptide were investigated, namely, its effects on passive avoidance behavior, exploratory behavior and body temperature. The interaction of Ac-VP with the central nervous system effects of vasopressin (VP) was also studied. Ac-VP had a slight agonistic effect on passive avoidance behavior, i.e. it facilitated passive avoidance behavior at a dose 100 times higher than that of VP. Relatively low doses (3-10 ng) of Ac-VP attenuated passive avoidance behavior, which suggests that Ac-VP interfered with an endogenous compound involved in the control of passive avoidance responding. Ac-VP was also able, albeit in higher doses (30 ng), to competitively antagonize the effect of [Cyt6]VP-(5-9), a highly potent, putative endogenous metabolite of vasopressin in the rat brain. This antagonism could be due to an interaction of Ac-VP with sites other than the V1 vasopressin receptor. Ac-VP had no significant influence on other central nervous system effects of the hormonally active nonapeptide VP, such as exploratory behavior and body temperature. These effects were readily antagonized by the V1 vasopressin receptor antagonist d(CH2)5Tyr(Me)VP. Ac-VP may be competitive antagonist of behaviorally active vasopressin metabolite(s) in the brain.

N-acetyl-vasopressin- and N-acetyl-oxytocin-like substances: isolation and characterization in the rat neurointermediate pituitary and presence in the brain

Abstract Post-translational modifications of vasopressin and oxytocin in pituitary and brain were investigated in view of recent evidence that oxytocin is partly N(alpha)-acetyfated in the bovine pineal gland. Two peptides were isolated from the neurointermediate lobe of the rat pituitary gland and characterized as N(alpha)-acetyl-vasopressin and N(alpha)-acetyl-oxytocin, based on chromatographic and immunological properties as well as the blocked N-terminus. In the neurointermediate pituitary the acetylated forms represented approximately 1% of the vasopressin and oxytocin contents. These two peptides were also detected in some, but not all, investigated brain areas. The highest degree of acetylation was found in the pineal gland. In all regions acetylation of oxytocin was more abundant than that of vasopressin. The data indicate that acetylation of vasopressin and oxytocin generally occurs as a post-translational modification. They support the concept that acetylation may represent a mechanism aimed to control bioactivity of the neurohypophyseal hormones.

Changes in vasopressin-converting aminopeptidase activity in the rat pineal gland during summer: relationship to vasopressin contents

Vasopressin (VP)-converting aminopeptidase (VP-AP) activity and VP contents were measured in single rat pineal glands during the summer of two successive years. The peptidase activity decreased significantly in August. The lowest activity (+/- SEM) of 0.18 +/- 0.02 pmol.hour-1 was recorded on August 14, compared to the basal activity of 0.25 +/- 0.01 pmol.hour-1 in July and September of 1986. The change with similar percentage occurred in the same period of 1987. The specific activity of the enzyme in the crude homogenate, 15,000 g pellet and supernatant fraction of rat pineal glands, exhibited the same pattern of variations. The decrease in peptidase activity coincided with the previously reported dramatic rise in pineal VP content in early August which was confirmed in this series of experiments. Another peptidase, the so-called gamma-endorphin generating endopeptidase (gamma-EGE) activity, and beta-endorphin-related peptides in the pineal gland did not change in this period. The results show that the variations of pineal VP contents and VP-AP activity during summer are not general for other peptides and peptidases. The coincidence of opposite changes in VP content and VP-AP activity of the pineal gland may indicate a role of the peptidase activity to regulate the VP content.

Atrial natriuretic factor R1 receptor from bovine adrenal zona glomerulosa: purification, characterization, and modulation by amiloride

The atrial natriuretic factor (ANF) R1 receptor from bovine adrenal zona glomerulosa was solubilized with Triton X-100 and purified 13,000-fold, to apparent homogeneity, by sequential affinity chromatography on ANF-agarose and steric exclusion high-performance liquid chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining of the purified receptor preparation in the absence or presence of dithiothreitol revealed a single protein band of Mr 130,000. Affinity cross-linking of 125I-ANF to the purified receptor resulted in the labeling of the Mr 130,000 band. The purified receptor bound ANF with a specific activity of 6.8 nmol/mg of protein, corresponding to a stoichiometry of 0.9 mol of ANF bound/mol of Mr 130,000 polypeptide. Starting with 500 g of adrenal zona glomerulosa tissue, we obtained more than 500 pmol of purified receptor with an overall yield of 9%. The purified receptor showed a typical ANF-R1 pharmacological specificity similar to that of the membrane-bound receptor. The homogeneous Mr 130,000 receptor protein displayed high guanylate cyclase activity [1.4 mumol of cyclic GMP formed min-1 (mg of protein)-1] which was not stimulated by ANF. This finding supports the notion that the ANF binding and the guanylate cyclase activities are intrinsic components of the same polypeptide. Finally, the purified ANF-R1 receptor retained its sensitivity to modulation by amiloride, suggesting the presence of an allosteric binding site for amiloride on the receptor protein.

Detection of autocrine motility factor in urine as a marker of bladder cancer

Cell locomotion is an essential requirement for invasion and metastasis of malignant cells. We have previously described the characterization of a 50-kilodalton autocrine motility factor (AMF), a cytokine that stimulates motility in human tumor cells. In this study, we investigated the elaboration of this factor in vivo by human bladder carcinoma and in vitro by a cultured transitional cell carcinoma (TCC) of the bladder cell line T24P. Urine samples from patients with bladder cancer were assayed for their capacity to stimulate migration of tumor cells. Comparing all TCC cases (22 patients) with all nonmalignant diagnoses (27 patients), we found a statistically significant (P less than .001) difference in the motility values. Invasive TCC cases (15 patients) were significantly (P less than .002) higher in regard to motility values compared with noninvasive TCC cases (8 patients), including one case of carcinoma in situ. In follow-up screening studies evaluating TCC recurrence, the recurrent tumors (9 patients) were higher (P less than .001) in regard to motility values than the tumor-free cases (11 patients). Furthermore, T24P cells showed a dose-dependent motile response to their own serum-free conditioned medium as well as to the AMF present in the urine of TCC patients. This finding is consistent with the source of AMF in the urine of these patients being the cancer itself. An enzyme-linked immunosorbent assay (ELISA) for AMF was also developed. Values determined by ELISA correlated well with the motility values measured separately. These data support the potential usefulness of AMF as a urine marker for bladder TCC.

The identification of furanose and pyranose ring forms of the reducing units of oligosaccharides

Several types of oligosaccharides with glucose, arabinose, or galactose units have been prepared by chemical degradation of oligosaccharides of known structures and by enzymatic syntheses utilizing macerans amylase or yeast galactosyltransferase and appropriate substrates and cosubstrates. The ring forms of reducing units of these oligosaccharides and of oligosaccharides composed of glucose and mannose have been identified by a combined method of analysis based on methylation, gas-liquid chromatography, and mass spectrometry. In the dimethyl sulfoxide solvent used for the methylations, the oligosaccharides with arabinose or galactose units at the reducing ends occur as arabinofuranose or galactofuranose ring forms to the extent of 55 and 65%, respectively. The remainder of these monosaccharide units are present in the pyranose ring form. Oligosaccharides with glucose or mannose units at the reducing ends occur primarily in the pyranose ring form. An interesting observation is the finding that the reducing units which carry substituents linked by alpha-glycosidic linkages occur in a higher percentage in the furanose ring forms than those which carry substituents linked by beta-glycosidic linkages.

Diurnal variation in vasopressin and oxytocin messenger RNAs in hypothalamic nuclei of the rat

Diurnal changes in the expression of the vasopressin (VP) and oxytocin (OT) genes in the supraoptic (SON), paraventricular (PVN) and suprachiasmatic nuclei (SCN) of the rat were investigated by dot-blot and in situ hybridization of the VP and OT mRNAs. A significant diurnal variation in VP mRNA level was measured in the SCN, with highest levels around 17.00 h and lowest levels around midnight. No variations in levels of VP mRNA and OT mRNA were detected in SON and PVN. The data indicate that the regulation of the VP gene in the SCN is independent of that in the magnocellular nuclei.

Circadian variations of vasopressin level and vasopressin-converting aminopeptidase activity in the rat pineal gland

Vasopressin levels and vasopressin-converting aminopeptidase activity were measured in the rat pineal gland during the 24 hr light-dark cycle. A rhythmic variation in peptide levels and peptidase activity occurred. At the onset of light at 6.00 hr, the peptidase displayed a significant, short-lasting (approximately 3 hr) increase of about 35% in activity, while a decrease of 28% in pineal vasopressin levels was observed. The changes in peptidase activity and peptide level were not triggered by light per se, since they persisted to occur at the same time point in animals which were not exposed to light, indicating the circadian nature of the rhythmicity. These changes were specific to the pineal gland, since other tissues, like hippocampus and pituitary gland, did not show these daily variations. The data suggest a relationship between vasopressin levels and vasopressin-converting aminopeptidase activity.

Glucose-6-phosphate dehydrogenase deficiency among three national minorities in Hainan Island, China

A total of 296 healthy males belonging to three national minority groups, Li, Miao and Hui, in Hainan Island, China, were screened for G6PD deficiency. 9 out of 139 Li (6.47%), 8 out of 48 Miao (16.67%), and 2 out of 109 Hui (1.83%) individuals were found to be G6PD deficient. Of these 19 variant samples, three were subjected to G6PD characterization and found to be different from each other. They were considered to be G6PD Miaozu-Baisha, G6PD Qingyuan, and a new variant tentatively named G6PD Huizu-Sanya.

Oxytocin and vasopressin gene expression in the hypothalamo-neurohypophyseal system of the rat during the estrous cycle, pregnancy, and lactation

To study the state of hypothalamic expression of the oxytocin (OT) and vasopressin (VP) genes in different conditions of the female rat, OT and VP mRNA levels were determined during the estrous cycle, pregnancy, and lactation. OT and VP mRNA levels of the supraoptic nucleus were quantified by Northern blot and dot-blot analysis. OT and VP contents of the pituitary gland were determined by RIA. During the estrous cycle, OT mRNA levels of the supraoptic nucleus were significantly increased 1.5- to 2-fold at estrous relative to the other periods of the cycle. No significant cyclic variation was observed in VP mRNA levels. The OT content of the pituitary gland was significantly decreased at estrus and also the VP contents showed a cyclic variation with the lowest levels occurring at estrus and metestrus. At the last day of gestation a 3- and 2-fold increase of OT mRNA and VP mRNA, respectively, was measured, but no changes were observed at gestational day 12, 15, and 18. In rats lactating for 15 days, OT and VP mRNA levels were approximately 3-fold higher than during the estrous cycle. Concomitantly the OT and VP contents of the pituitary gland were decreased by approximately 50%. It is concluded that both OT and VP gene expression are stimulated just before birth and during lactation indicating that both genes are sensitive to common factors. A dissociation of the regulation of the OT and VP genes occurs in the estrous cycle.

Isolation and identification of vasopressin- and oxytocin-immunoreactive substances from bovine pineal gland. Presence of N alpha-acetyloxytocin

Peptides with vasopressin- and oxytocin-immunoreactivity were purified from bovine pineal glands. Three immunoreactive peptides were purified by successive high performance liquid chromatography steps in sufficient quantities for identification by fast atom bombardment-mass spectrometry. Two peptides were characterized as authentic vasopressin and oxytocin. Their identities were in agreement with the observed immunoreactivities, high performance liquid chromatography behavior, and biological activity. The third peptide was identified as N alpha-acetyloxytocin. The presence of the acetyl group was demonstrated by the molecular mass of the peptide, and the N alpha position was shown to be the modified site by the presence of a blocked NH2 terminus. N alpha-Acetylation of oxytocin may be involved in altering the biological properties of the peptide.

Detection and high performance liquid chromatography identification of the summer rises of vasopressin and oxytocin immunoreactivity in the rat pineal gland

The vasopressin (VP) and oxytocin (OT) contents of the rat pineal gland during the summer period were determined by RIAs. Both the levels of VP immunoreactivity and OT immunoreactivity rose markedly in August. The highest level of VP immunoreactivity occurred on August 6 [82 +/- 19 fmol/gland (+/- SEM)], compared to basal levels of 14 +/- 2 fmol/gland. Basal levels of OT immunoreactivity of 20 +/- 8 fmol/gland increased to a peak level of 193 +/- 72 fmol/gland on August 14. Analysis of immunoreactive components by HPLC demonstrated that rises were due to the peptides coeluting with authentic VP and OT, respectively. Levels of immunoreactive VP and OT in the hypothalamus, pituitary gland, and hippocampus did not show variation during the summer. The results show that the VP and OT content of the pineal gland is regulated in a tissue-specific fashion by seasonal influences.

Characterization of vasopressin and oxytocin immunoreactivity in the sheep and rat pineal gland: absence of vasotocin and detection of a vasopressin-like peptide

The presence of arginine-vasopressin (VP), arginine-vasotocin (VT) and oxytocin (OT) were studied in sheep and rat pineal gland by the combination of HPLC and radioimmunoassays. Three immunoreactive substances, which had the same retention time as OT, VP and VT, were detected in sheep and rat pineal extracts after HPLC separation. Parallelism of dilution curve and standard curve demonstrated that two of them were identical to OT and VP respectively. The third component was distinct from VT on basis of its immunological reaction with two different antibodies; it resembled the immunoreactivity of VP. This substance was also detected in the hypothalamus, brain cortex and pituitary gland, but not in the hippocampus and adrenal gland. The results support the notion that VT is absent in the adult mammalian pineal gland and point to the existence of another, possibly related peptide.