Central catecholaminergic neurons are involved in expression of the 10-Hz rhythm in SND

We studied the effects of adrenoceptor agonists and antagonists on sympathetic nerve discharge (SND) of urethan-anesthetized, baroreceptor-denervated cats. In cats in which a 10-Hz rhythm coexisted with irregular 2- to 6-Hz oscillations in SND, intravenous clonidine, an alpha 2-adrenoceptor agonist, blocked the 10-Hz rhythm without affecting power at lower frequencies. In contrast, power at frequencies < or = 6 Hz was depressed by clonidine in cats in which the 10-Hz rhythm was absent. These effects were reversed by intravenous administration of alpha 2-adrenoceptor antagonists, idazoxan and rauwolscine. Rauwolscine is devoid of affinity for imidazoline receptors. Furthermore, in cats untreated with clonidine, idazoxan and rauwolscine enhanced or induced the 10-Hz rhythm without affecting power at lower frequencies. Prazosin, an alpha 1-adrenoceptor antagonist, selectively blocked the 10-Hz rhythm in SND. Finally, the 10-Hz rhythm in SND was blocked by microinjection of clonidine into the rostral or caudal ventrolateral medulla. The results support the view that central catecholaminergic neurons play a role in expression of the 10-Hz rhythm in SND.

Role of serotonergic neurons in the maintenance of the 10-Hz rhythm in sympathetic nerve discharge

We studied the effects of serotonin (5-HT)-receptor agonists and antagonists on the naturally occurring 10-Hz rhythm in sympathetic nerve discharge (SND) of urethan-anesthetized, baroreceptor-denervated cats. Intravenous doses of the 5-HT1A-receptor agonists 8-hydroxy-2(di-n-propylamino)-tetralin (8-OH-DPAT) and U-93385E, which inhibit the firing of serotonergic medullary raphe neurons, decreased the power in the 10-Hz band of SND without affecting the power at frequencies < or = 6 Hz. The inhibitory effects of 8-OH-DPAT and U-93385E were reversed by the 5-HT1A-receptor antagonists spiperone and WAY-100135. Microinjection of 8-OH-DPAT into medullary raphe nuclei also selectively eliminated the 10-Hz rhythm in SND. Intravenous administration of the 5-HT2-receptor antagonist methysergide blocked the 10-Hz rhythm in SND, whereas the 5-HT2-receptor agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-amino-propane increased peak frequency and power in the 10-Hz band of SND. Microinjection of N-methyl-D-aspartic acid into the medullary raphe also enhanced the 10-Hz rhythm in SND. These data support the view that the naturally occurring discharges of serotonergic medullary raphe neurons preferentially enhance the 10-Hz rhythm in SND.

Physical and functional interactions between p53 and cell cycle co-operating transcription factors, E2F1 and DP1

One way in which wild-type p53 is able to regulate cell cycle progression is thought to be via the induction of its downstream target gene Waf1/CIP1, thus indirectly regulating the transcriptional activity of E2F. The E2F transcription factors are known to be key effectors of the cell cycle. We report here that there is a physical and functional interaction between p53 and two of the components of the E2F transcription factors, E2F1 and DP1. The expression of wild-type p53 can inhibit the transcriptional activity of E2F, and the expression of both E2F1 and DP1 can also downregulate p53-dependent transcription. The transcriptional activity of p53 is known to be inhibited by the direct binding of mdm2, but we demonstrate here that both E2F1 and DP1 can inhibit p53 transcriptional activity independently of mdm2. Detailed studies of protein-protein interactions have provided evidence that E2F1 and its co-operating factor DP1 can complex with p53 both in vitro and in vivo.

[153Sm-EDTMP for moderate and severe bone cancer pain]

One hundred and thirty-six patients with bone cancer pain were treated with 153Sm-EDTMP (ethylenediamine-tetramethylene phosphonic acid). Pain free was noted in 49 cases (36%, 49/136) and pain relief in 77 cases (56.6%, 77/136), the total relief rate being 92.6% (126/136). The data from 76 patients with moderate and severe pain showed there were no significant relationships between the patients' age, the dose of 153Sm-EDTMP and the analgesic effects (P > 0.05). The pain relief observed in the patients with chest pain (ribs metastases) was earlier than that in other groups (P < 0.05). We didn't find any clinical side-effects, so 153Sm-EDTMP is safe for use.

[Inhibition of hepatitis B viral gene expression and replication in vitro by targeted antisense oligonucleotides]

We chose the 2.2. 15 cells as an in vitro cell culture assay system, and identified the surface antigen subtype of hepatitis B virus (HBV) DNA in the cells, by using the amplification of polymerase chain reaction and directed sequencing of amplified products. According to the result of the sequencing, a 16-mer phosphorothioate analogue of the antisense oligonucleotide (PS-ASON) directed against the HBV U5-unique region was synthesized and then linked with two liver-targeting ligands. The galactosylated human serum albumin coupled poly-L-lysine and the galactosylated poly-L-lysine. The effect of different modifications of ASONs on the expression of HBV gene was compared by using the 2.2. 15 cells. In the same experimental conditions, the inhibitary effects of surface antigen (HBsAg) and antigen (HBeAg) by PS-ASON were 70% and 58% respectively, and those of HBsAg and HBeAg by ligand-PS-ASONs were 90%-96% and 78%-82%. In the same time, the amount of HBV NDA in culture supernatant and cells was depressed significantly. Thus, the ligands targeted ASON to the hepatocytes were more effective inhibitors of HBV gene expression. ASONs were effective and specific inhibitors of HBV replication and expression, caused the dose-dependent inhibition of viral proteins and had no effect on cellular alpha-fetoprotein synthesis and no cytotoxicity.

[Effect of 153Sm-EDTMP on hematopoiesis and vital organs of 93 patients with bone tumor]

In the present study data on blood cell count, serum biochemistry, electrolyte, enzyme and vital organs of 93 patients with bone tumor or metastasis were investigated before and after treatment with 153Sm-EDTMP. The results showed that, 7 days and 30 days after the administration of 153Sm-EDTMP (< 29.6 MBq) (0.8 mCi/kg), the levels of hemoglobin, WBC lymphocyte count, and the liver and kidney function of all patients were not significantly different from the baseline data before treatment (P > 0.05). Although at 7 days, there was a declination of the granulocyte count, it returned to normal at 30 days (P > 0.05). The platelet count was significantly decreased (0.05 > P > 0.01). at 30 days after the administration of 153Sm-EDTMP. Thirteen patients received 74-185 MBq (2-5mCi/kg) and their myelo biopsies at 3 and 18 months showed no sign of acute or chronic toxicosis.

Synchronization of cardiac-related discharges of sympathetic nerves with inputs from widely separated spinal segments

We used phase spectral analysis to study the relationships between the cardiac-related discharges of pairs of postganglionic sympathetic nerves in urethan-anesthetized or decerebrate cats. Phase angle when converted to a time interval should equal the difference in conduction times from the brain to the nerves (i.e., transportation lag) if their cardiac-related discharges have a common central source. Transportation lag was estimated as the difference in the onset latencies of activation of the nerves by electrical stimulation of the medulla or cervical spinal cord. The phase angle for the cardiac-related discharges of two nerves was not always equivalent in time to the transportation lag. For example, in some cases the cardiac-related discharges of the renal nerve were coincident with or led those of the inferior cardiac nerve. In contrast, the electrically evoked responses of the renal nerve lagged those of the inferior cardiac nerve by > or = 32 ms. These observations are consistent with a model of multiple and dynamically coupled brain stem generators of the cardiac-related rhythm, each controlling a different sympathetic nerve or exerting nonuniform influences on different portions of the spinal sympathetic outflow.

Biological and structural characterization of a Ras transforming mutation at the phenylalanine-156 residue, which is conserved in all members of the Ras superfamily

Although Ras residue phenylalanine-156 (F156) is strictly conserved in all members of the Ras superfamily of proteins, it is located outside of the consensus GDP/GTP-binding pocket. Its location within the hydrophobic core of Ras suggests that its strict conservation reflects a crucial role in structural stability. However, mutation of the equivalent residue (F157L) in the Drosophila Ras-related protein Rap results in a gain-of-function phenotype, suggesting an alternative role for this residue. Therefore, we have introduced an F156L mutation into Ras to evaluate the role of this residue in Ras structure and function. Whereas introduction of this mutation activated the transforming potential of wild-type Ras, it did not impair that of oncogenic Ras. Further, Ras (156L) exhibited an extremely rapid off rate for bound GDP/GTP in vitro and showed increased levels of Ras.GTP in vivo. To determine the structural basis for these altered properties, we used high-resolution nuclear magnetic resonance spectroscopy. The F156L mutation caused loss of contact with residues 6, 23, 55, and 79, resulting in disruption of secondary structure in alpha-helix 1 and in beta-sheets 1-5. These major structural changes contrast with the isolated alterations induced by oncogenic mutation (residues 12 or 61) that perturb GTPase activity, and instead, weaken Ras contacts with Mg2+ and its guanine nucleotide substrate and result in increased rates of GDP/GTP dissociation. Altogether, these observations demonstrate the essential role of this conserved residue in Ras structure and its function as a regulated GDP/GTP switch.

Mantle Convection with Plates and Mobile, Faulted Plate Margins

A finite-element formulation of faults has been incorporated into time-dependent models of mantle convection with realistic rheology, continents, and phase changes. Realistic tectonic plates naturally form with self-consistent coupling between plate and mantle dynamics. After the initiation of subduction, trenches rapidly roll back with subducted slabs temporarily laid out along the base of the transition zone. After the slabs have penetrated into the lower mantle, the velocity of trench migration decreases markedly. The inhibition of slab penetration into the lower mantle by the 670-kilometer phase change is greatly reduced in these models as compared to models without tectonic plates.

Differential relationships among 10-Hz rhythmic discharges of sympathetic nerves with different targets depend on supraspinal rather than spinal mechanisms

In urethane-anesthetized cats, ordinary and partial coherence values relating the 10-Hz rhythmic discharges of sympathetic nerves located on opposite sides of the body were not significantly affected by midsagittal section of the spinal cord from the seventh cervical through eighth thoracic or first cervical through eighth cervical segments. Thus, coordination of the 10-Hz discharges of the nerves occurred at a supraspinal level.

The functional significance of the 10-Hz sympathetic rhythm: a hypothesis

This paper reviews work from our laboratory on the 10-Hz rhythm in sympathetic nerve discharge of the cat and offers a hypothesis on its functional significance. The rhythm is ubiquitous to the discharges of sympathetic nerves with different cardiovascular targets and arises from a system of coupled nonlinear brain stem oscillators, each of which has a selective relationship with a different portion of the spinal sympathetic outflow. The 10-Hz rhythmic discharges of sets of sympathetic nerves are differentially related and the pattern of relationships in one experiment can be the reverse of that in the next. We hypothesize that nonuniform and dynamic coupling of the central circuits controlling different sympathetic nerves is the basis for the formulation of complex cardiovascular response patterns that include differential changes in regional blood flows.

The autocrine regulatory effect of vasoactive intestinal peptide on the growth of human pancreatic carcinoma cells

In the present study, the effects of VIP on the growth of two human pancreatic carcinoma cell lines PU-PAN-1 and PANC-1 were determined using tritiated thymidine incorporation. VIP receptors, intracellular cAMP and polyamines were investigated. The results indicated that VIP at a concentration of 10(-8) mol/L to 10(-7) mol/L can significantly stimulate the growth of PU-PAN-1 cells but not PANC-1 cells. This effect is dose-dependent and abolished by VIP receptor antagonist, [4-C1-Phe6, Leu17] VIP, suggesting VIP receptors in PU-PAN-1 cells may mediate this effect. VIP can markedly elevate the levels of intracellular cAMP and polyamines in PU-PAN-1 cells, indicating that the growth-promoting effect stimulated by VIP may be via a rapid increase in the biosyntheses of cAMP and polyamines. In addition, the VIP-antibody inhibited the growth of PU-PAN-1 cells in serum-free culture medium. The results above suggested that VIP has an autocrine regulatory effect on this pancreatic carcinoma cell line (PU-PAN-1).

Human ApoA-II inhibits the hydrolysis of HDL triglyceride and the decrease of HDL size induced by hypertriglyceridemia and cholesteryl ester transfer protein in transgenic mice

The plasma cholesteryl ester transfer protein (CETP) mediates the exchange of HDL cholesteryl esters with triglycerides of other lipoproteins. Subsequent lipolysis of the triglyceride-enriched HDL by hepatic lipase leads to reductions of HDL size and apoA-I content. To investigate a possible modulation of the effects of CETP by apoA-II, human CETP transgenic mice were cross-bred with transgenic mice expressing human apoA-II and, in some cases, human apoA-I and apoC-III (with human-like HDL and hypertriglyceridemia). CETP expression resulted in reductions of HDL and increases in VLDL cholesteryl ester in mice expressing human apoA-II, alone or in combination with apoA-I and apoC-III, indicating that apoA-II does not inhibit the cholesteryl ester transfer activity of CETP. However, CETP expression resulted in more prominent increases in HDL triglyceride in mice expressing both apoA-II and CETP, especially in CETP/apoA-II/apoAI-CIII transgenic mice. CETP expression caused dramatic reductions in HDL size and apoA-I content in apoAI-CIII transgenic mice, but not in apoA-II/AI-CIII transgenic mice. HDL prepared from mice of various genotypes showed inhibition of emulsion-based hepatic lipase activity in proportion to the apoA-II/apoA-I ratio of HDL. The presence of human apoA-II also inhibited mouse plasma hepatic lipase activity on HDL triglyceride. Thus, apoA-II does not inhibit the lipid transfer activity of CETP in vivo. However, coexpression of apoA-II with CETP results in HDL particles that are more triglyceride enriched and resistant to reductions in size and apoA-I content, reflecting inhibition of hepatic lipase by apoA-II. The inhibition of HDL remodeling by apoA-II could explain the relatively constant levels of HDL containing both apoA-I and apoA-II in human populations.

A modulatory role of central cholinergic transmission in control of the 10-Hz rhythm in sympathetic nerve discharge

In 43 urethane-anesthetized or decerebrate, baroreceptor-denervated cats, spectral analysis showed that most of the power in sympathetic nerve discharge (SND) was at frequencies < 6 Hz. In 18 of these cats, physostigmine (100 micrograms/kg i.v.) induced a 10-Hz rhythm in inferior cardiac SND that was eliminated by atropine sulfate (0.25 mg/kg i.v.; n = 6). In contrast, the naturally occurring 10-Hz rhythm that appeared in SND in other experiments was atropine-insensitive (n = 6). The data indicate that central muscarinic cholinergic transmission is not essential for the naturally occurring 10-Hz rhythm. Nonetheless, facilitation of cholinergic transmission can induce a 10-Hz rhythm.

Postnatal development in rat offspring delivered of dams with gestational hyperglycemia

OBJECTIVES

Our purpose was to test the hypotheses that (1) offspring delivered of dams with gestational hyperglycemia will show metabolic abnormalities and (2) dams with repeated pregnancy but without lactation experience will demonstrate abnormal glucose metabolism long after the delivery of the third litter.

STUDY DESIGN

Female rats went through three cycles of gestation-lactation, gestation-nonlactation, or no mating at all. The offspring were reared to 3 months of age, when half of each group were mated. Intravenous glucose tolerance testing was conducted at different times in dams and adult offspring.

RESULTS

Nonlactation dams showed gestational hyperglycemia, insulin resistance, and hyperlipidemia during the third pregnancy. Impaired intravenous glucose tolerance testing was also apparent 1 week and 3 months after weaning in dams. Adult offspring nursed by nonlactation dams were glucose intolerant and had higher hepatic gluconeogenic enzyme activities and higher lipid levels in the pregnant state.

CONCLUSION

Gestational hyperglycemia produced by repeated gestation without lactation could have a long-lasting effect on adult offspring.

65 cases of preserving pylorus pancreatoduodenectomy: experience and problems

Sixty-five patients with neoplasm (62 cases) or pancreatitis (3 cases) were treated with preserving pylorus pancreatoduodenectomy (PPPD) from 1984 to 1991. One postoperative death occurred. Follow-up studies were performed in 35 patients who had been treated by PPPD or the standard Whipple's procedure; they were questioned carefully concerning clinical symptoms. Further studies were performed in 20 patients with or without pylorus preservation (10 patients, respectively). Nutritional status and gastrointestinal digestive and absorptive functions were evaluated by determination of serum components, gastric analysis, barium emptying time, D-xylose absorption test, 14CO2 breath test, PABA, and other methods. The results demonstrated malnutrition and postgastrectomy syndromes in some patients after the standard Whipple's procedure, but not in those with PPPD. The quality of life was better in the latter. Pylorus preservation may be the main reason for this above difference. Delayed gastric emptying in the early postoperative period was a complication in some patients (21%) treated by PPPD. We recommend PPPD for pancreatoduodenectomy.

Impact of annual screening and chemotherapy with praziquantel on schistosomiasis japonica on Jishan Island, People's Republic of China

The impact of annual screening and treatment with praziquantel on schistosomiasis japonica was examined on Jishan Island in Po Yang Lake, Jiangxi Province. China. Prevalence of infection in the community decreased from 39% in year 1 to 33% in year 3 with a corresponding decrease in the geometric mean egg count from 51 eggs per gram of stool (epg) to 31 epg. The most dramatic changes in infection status and intensity of infection were observed in younger individuals (0-19 years of age). The prevalence of hepatosplenomegaly also significantly decreased, again primarily in younger individuals. No change in the community prevalence of schistosome-induced hepatic fibrosis was observed as determined by ultrasonography. Longitudinal cohort analysis, however, demonstrated significant improvement in treated individuals with advanced hepatic fibrosis. These data indicate that annual screening and treatment had a significant impact on infection status and morbidity and suggest that community therapy may be an effective approach to control schistosomiasis japonica in lake regions and marshlands in China. Further studies are necessary to determine the optimal and most cost-effective approach for drug delivery.

Biomolecular applications of heteronuclear multidimensional NMR

Recent advances in stable-isotope enrichment and heteronuclear multidimensional NMR techniques have transformed NMR into a more powerful and versatile method for the structural and dynamic characterization of biomolecules. Current efforts still focus on improving the methodology to increase the number of systems amenable to NMR analysis, to generate better structures and to investigate biomolecular motions in solution.

Differential relationships among the 10-Hz rhythmic discharges of sympathetic nerves with different targets

Partial coherence analysis was used to remove the influences of the central circuits controlling a sympathetic nerve (as reflected by its discharges) on the coherence of the 10-Hz discharges of other sympathetic nerves in unanesthetized decerebrate or urethan-anesthetized cats. In many cases, partialization reduced but did not eliminate the sharp peak near 10 Hz in the coherence functions relating the discharges of sympathetic nerve pairs. This observation implies that the central sources of the 10-Hz rhythmic discharges of any nerve are not identical to those responsible for the rhythm recorded from any other nerve. Partial coherence analysis also revealed differential relationships among the 10-Hz rhythmic discharges of sympathetic nerves with different targets. Importantly, the pattern of differential relationships observed in one experiment could be the reverse of that in the next. Although the basis for the differential relationships is not yet clear, nonuniform coupling of multiple brain stem 10-Hz oscillators and/or nonuniform cross talk between spinal circuits controlling different sympathetic nerves may be involved.

Coordination of the cardiac-related discharges of sympathetic nerves with different targets

Partial coherence analysis was used to remove the influences of pulse-synchronous baroreceptor nerve activity (as reflected by the arterial pulse) on the coherence of the cardiac-related discharges of sympathetic nerve pairs in unanesthetized decerebrate cats. It can be predicted that the peak at the heart rate frequency in the ordinary coherence function relating the discharges of two nerves will be eliminated by either partialization using the arterial pulse or surgical baroreceptor denervation, if the central circuits controlling the nerves share baroreceptor inputs but are not interconnected. Contrary to this prediction, in many experiments the peak was not eliminated by partialization using the arterial pulse. Moreover, partialization often nonuniformly reduced the peaks at the heart rate frequency in the coherence functions for different nerve pairs. These results are consistent with a model of multiple routes over which baroreceptor influences are distributed to the central circuits controlling different sympathetic nerves. Specifically, we propose that the direct route from the baroreceptors to each of the central circuits is complemented by cross talk among the central circuits.

Gender effects on the distribution of the cholesteryl ester transfer protein in apolipoprotein A-I-defined lipoprotein subpopulations

Two subpopulations of apolipoprotein A-I-containing lipoproteins, those containing only apoA-I (LpA-I) and those containing both apoA-I and apoA-II (LpA-I/A-II), were isolated by immunoaffinity chromatography of plasma from 44 subjects, comprising four groups (male or female, with or without hyperlipidemia). ApoA-I-defined particles (LpAs) were assessed for their content of cholesteryl ester transfer protein (CETP) and for their ability to act as substrates for CETP. Although plasma CETP concentration was similar in all groups, the plasma concentration of LpA-I-associated CETP was significantly higher in females than in males (1.56 +/- 0.11 versus 0.93 +/- 0.13 mg/l, P < 0.05). In females, the major fraction of CETP was found in LpA-I, whereas in normolipidemic males CETP was evenly distributed between LpA-I and LpA-I/A-II, and in hyperlipidemic males the majority of CETP was found in LpA-I/A-II. In all groups, the percentage of CETP in LpA-I was correlated with the concentration of apoA-I in LpA-I (r = 0.64, P < 0.001). Native gradient gel electrophoresis of isolated LpAs showed that CETP was broadly distributed within different sized particles. LpA-I and LpA-I/A-II showed similar efficiency of CETP-mediated cholesteryl ester exchange with LDL. In conclusion, even though LpA-I has a much higher apparent affinity for CETP than LpA-I/A-II, both LpAs can bind CETP and act as equivalent CETP substrates in vitro. Thus, in subjects with low levels of LpA-I (notably hyperlipidemic males), most of the plasma neutral lipid exchange will involve LpA-I/A-II.(ABSTRACT TRUNCATED AT 250 WORDS)

Potentiation of glucocorticoid receptor-mediated gene expression by heat and chemical shock

We have examined the effects of heat shock on glucocorticoid receptor (GR)-mediated gene transcription in an L929 cell line derivative (LMCAT2) stably transfected with the mouse mammary tumor virus-chloramphenicol acetyltransferase (MMTV-CAT) reporter plasmid. Exposure of the LMCAT2 cells to heat or chemical shock resulted in a large increase in dexamethasone (Dex)-induced expression of CAT enzyme activity. This potentiation of hormone-induced MMTV-CAT expression was dependent on the magnitude of the stress event and on the Dex concentration, with maximal increases observed for 1 microM Dex after 2 h at 43 C or 2 h at 200 microM sodium arsenite. Heat shock potentiation of MMTV-CAT expression was not seen in an L929 cell derivative devoid of GR or in LMCAT2 cells treated with RU486 antagonist, suggesting that this effect of stress on CAT gene expression was mediated by the GR. Using a quantitative Western blot procedure, the amount of GR protein in the nucleus of cells subjected to combined heat shock and Dex treatment was no greater than the amount of nuclear GR in cells treated with hormone alone, indicating that the stress potentiation effect was not the result of increased nuclear translocation or retention by the GR. In addition, equally strong potentiations of MMTV-CAT expression were observed for cells subjected to heat shock either before or after Dex-mediated translocation of the GR to the nucleus. Thus, the major effect of stress on GR transcription enhancement activity appears to occur after the GR is bound to its high affinity nuclear acceptor sites. We have used a series of MMTV-CAT reporter constructs containing varying portions of the long terminal repeat regulatory region to show that a putative heat shock transcription factor-binding sequence at position -437 of the long terminal repeat is not required for this effect of heat shock on MMTV-CAT expression. A stress-induced increase in hormone-mediated CAT gene expression was observed for a minimal CAT reporter controlled by two synthetic glucocorticoid response elements and a TATA box sequence. Thus, it is unlikely that any DNA-binding transcription factor, other than GR, is required for this effect of stress on transcription by the hormone-bound GR. Based on these results, a model of heat shock enhancement of GR-mediated gene expression is developed in which stress acts on the DNA-bound GR, on a putative heat shock-activated adaptor, or on components of the RNA-polymerase-II complex.

Chromosome assignment of the human glutathione S-transferase mu 3 gene (GSTM3) to chromosome 1 by gene specific polymerase chain reaction

Oligonucleotide primers specific for exons 4 and 5 sequences were used to amplify a unique 199-bp fragment in the human GSTM3 gene. Using DNA from a panel of somatic cell hybrids we assigned the GSTM3 locus to chromosome 1p.

Low dose fructose ingestion during gestation and lactation affects carbohydrate metabolism in rat dams and their offspring

This study examined whether drinking fructose or glucose water with a balanced diet affects pregnant and lactating rats and their offspring. The animals were divided into three groups and drank tap water, 100 g/L fructose water or 100 g/L glucose water. The fructose-fed dams ate significantly more food but drank less water than the glucose-fed group. On d 19 of pregnancy, the fructose-fed dams had significantly heavier livers and significantly higher plasma glucose and insulin concentrations than dams consuming tap water. Five days after litters were weaned, dams fed fructose had the heaviest body weights, significantly higher plasma glucose concentration compared with the group receiving tap water and significantly higher plasma triglyceride concentration compared with the glucose-fed group. Weanlings of the fructose-fed dams had significantly lower plasma glucose concentration but a significantly higher plasma insulin concentration than the weanlings of the group receiving tap water. These findings suggest that intake of fructose during gestation can cause hyperglycemia and hyperinsulinemia in dams and, at weaning, greater weight gain in dams and hyperinsulinemia in offspring. These abnormalities in dams and weanlings could be the result of insulin resistance.

Role of the brain stem in generating the 2- to 6-Hz oscillation in sympathetic nerve discharge

We tested the hypothesis that brain stem circuits normally generate a 2- to 6-Hz oscillation in sympathetic nerve discharge (SND). Experiments were performed on baroreceptor-denervated decerebrate cats and urethan-anesthetized rats in which renal or splanchnic SND was recorded along with field potentials (population activity) from sites in the rostral ventrolateral medulla, medullary raphe, or medullary lateral tegmental field. Our major findings were as follows. 1) Population activity recorded from the three medullary regions contained a 2- to 6-Hz oscillation. 2) The 2- to 6-Hz oscillation in population activity recorded from some medullary sites was correlated to that in SND. Peak coherence in the 2- to 6-Hz band approached a value of 1 in some cases. 3) Whereas cervical spinal cord transection abolished or markedly reduced SND, the 2- to 6-Hz oscillation in medullary activity was essentially unchanged. These results support the view that the 2- to 6-Hz oscillation in SND can be generated in the brain stem of cats and rats.

Relationship between the GSTM1 genetic polymorphism and susceptibility to bladder, breast and colon cancer

Mammalian cytosolic glutathione S-transferases (GSTs; EC 2.5.1.18) form a supergene family consisting of four distinct families, named alpha, mu, pi and theta. In humans one member of the mu class gene family (GSTM1) has been shown to be polymorphic and is only expressed in 55-60% of individuals. Previous studies have shown a possible link with the null phenotype and susceptibility to cancer, in particular to lung cancer. In this study we genotyped individuals with breast, bladder and colorectal cancer. A total of 490 individuals with cancer were studied, and consisted of 97 bladder, 197 breast and 196 colorectal cancers. No significant differences were observed in the frequency of nulled individuals in bladder or breast cancer patients when compared with a control population of 225 individuals. However, a significant excess of nulled individuals were seen in colorectal cancer: 56.1% compared with the control group value of 41.8%. This was shown to be highly significant depending on the site of the tumours and > 70% of individuals with a tumour in the proximal colon were GSTM1 nulled. This is an approximately 2-fold increase in colon cancer risk in these individuals.

Schistosomiasis japonica on Jishan Island, Jiangxi Province, People's Republic of China: persistence of hepatic fibrosis after reduction of the prevalence of infection with age

Hepatic fibrosis due to schistosomiasis japonica was examined by ultrasonography in a cross-sectional community study of 825 individuals on Jishan Island, Jiangxi Province, China. The prevalence of active infection was 39.4% with peak infection in the 10-19.9 years age group followed by a significant decline. A similar pattern was observed for intensity of infection. The prevalence of hepatomegaly in the midsternal line > or = 6 cm peaked at 60% in the fourth decade and remained elevated. A progressive increase in the severity of hepatic periportal fibrosis was observed with age, with advanced fibrosis peaking in the fifth decade. The proportion of individuals with advanced fibrosis was significantly greater in males than in females despite equivalent prevalence and intensity of schistosome infection. In addition, a positive association (P < 0.01) was found between periportal fibrosis and both hepatomegaly > or = 6 cm and splenomegaly. This study suggests that the natural history of schistosomiasis japonica in this hyperendemic community in China is marked by persistence of hepatomegaly and schistosome-induced periportal fibrosis in adults despite a decrease in the prevalence of infection.

The 10-Hz sympathetic rhythm is dependent on raphe and rostral ventrolateral medullary neurons

We studied the effects of brain stem and spinal lesions on the 10-Hz rhythms in left and right inferior cardiac sympathetic nerve discharge (SND) of baroreceptor-denervated, decerebrate cats. Unilateral medullary lesions [parasagittal section 1.5 mm lateral to midline, radiofrequency lesion of the rostral ventrolateral medulla (RVLM), or chemical inactivation (muscimol) of the RVLM] dramatically reduced the 10-Hz rhythmic discharges in the two nerves. Power in the 10-Hz band of ipsilateral inferior cardiac SND was reduced more than that in contralateral SND. In contrast, bilateral parasagittal medullary sections or microinjection of muscimol into the medullary raphe uniformly reduced the 10-Hz rhythmic discharges of both nerves. Unlike unilateral medullary lesions, rostral pontine or cervical spinal hemisection reduced the 10-Hz discharges of only the ipsilateral inferior cardiac nerve. The chemical inactivation experiments demonstrate that the 10-Hz rhythm in SND is dependent on medullary raphe and RVLM neurons. Moreover the experiments with unilateral lesions demonstrate a mutually facilitatory interaction of medullary circuits that are responsible for the 10-Hz rhythmic discharges in sympathetic nerves located on opposite sides of the body.

Deduced amino acid sequence, gene structure and chromosomal location of a novel human class Mu glutathione S-transferase, GSTM4

The Mu-Class glutathione S-transferases (GSTs) are subject to marked inter-individual variation in man, owing to the fact that 40-50% of the population fail to express M1 subunits. Mu-Class GST from two lymphoblastoid cell lines (expressing M1 subunits and the other 'nulled' for M1) have been studied. Both cell lines were found to express a Mu-Class GST that has not been described previously. The cDNA encoding this novel transferase, designated 'GSTM4' has been isolated and the enzyme shown to be comprised of 218 amino acids (including the initiator methionine residue) with an M(r) of approx. 25.5 kDa. Molecular cloning demonstrated that the lymphoblastoid cell line which expressed GSTM1 possessed the b allelic variant (i.e. that with an asparagine residue at position 173). The genes for GSTM4 and GSTM1b have been cloned and found to contain seven introns and eight exons. The coding region of the GSTM4 gene, including the seven introns, encompasses 5.0 kb, whereas the same region of GSTM1b is 5.5 kb; the difference in the size of the two genes is due to the length of intron 7. DNA sequencing allowed a GSTM4-gene-specific oligo-primer to be designed which has been utilized in a PCR-based assay to determine that the GSTM4 gene is located on chromosome 1.

Chromosomal assignment and linkage analysis of the human glutathione S-transferase mu gene (GSTM1) using intron specific polymerase chain reaction

Oligonucleotide primers specific for intron 5 sequences were used to amplify a unique 718 bp fragment in the human GST mu gene. Using DNA from a panel of somatic cell hybrids it was possible to confirm the assignment of the GST1 locus to chromosome 1p and to refine localisation to 1p13 using Southern blot analysis of DNA from three-generation CEPH families and a GST mu specific DNA probe.

Forced oscillations in sympathetic nerve discharge

Periodic electrical stimulation of the medullary raphe or lateral tegmental field in baroreceptor-denervated cats was used to force the central systems responsible for the 10-Hz and 2- to 6-Hz rhythms in post-ganglionic sympathetic nerve discharge (SND). The 10-Hz rhythm in SND could be entrained either to the frequency of medullary stimulation or to harmonics of the stimulus frequency. The harmonic of the stimulus frequency to which the 10-Hz rhythm was entrained in one postganglionic nerve could be different from that in another nerve. On this basis, we propose that the circuits responsible for the 10-Hz rhythms in SND may be modeled as a system of coupled nonlinear oscillators, each of which either influences one postganglionic nerve or nonuniformly affects different postganglionic nerves. The relatively wide band 2- to 6-Hz component in SND could be forced into a stable oscillatory state by medullary stimulation at frequencies between 3 and 5 Hz. This observation is consistent with the view that the 2- to 6-Hz component reflects the complex behavior of a nonlinear oscillator rather than the output of a physiological noise generator.

Long-term exercise training and retirement in genetically obese rats: effects on food intake, feeding efficiency and carcass composition

Short-term physical exercise (EX) can reduce body weight and fat gain in obese humans and animals. However, the beneficial effects of physical exercise are not long-lasting. In this study, the effects of long-term physical exercise and retirement from exercise (R) on body weight, body composition and fat distribution were examined in genetically obese (OB) and lean (LE) female rats. Fifty OB and 45 LE rats, four weeks old, were divided into EX (swimming, 2h/day, 5 days/week) or sedentary (SD) groups. At the end of the 28th week of treatment, EX groups were further divided into continued EX or R groups for another 11-12 weeks. It was found that at the end of the 28th week EX had reduced the rate of weight gain in OB and LE rats. Percentage body fat was only reduced in OBEX rats and this was achieved by a significant reduction of subcutaneous fat mass. At the end of the 40th week, EX had further reduced the weight gain, fat mass and body fat percentage in OBEX rats while only body fat percentage was reduced in the LEEX group. Retirement from exercise reversed these phenomena. Thus there were no differences between OBSD and OBEX-R rats in body weight, fat mass and percentage body fat. However, the OBEX-R group had a significantly higher amount of internal fat than the other two OB groups. Therefore, exercise, even long-term to cover the entire fat cell proliferation period, still only exerted temporary beneficial effects in OB rats. After retirement, the beneficial effects all disappeared rapidly.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of brain stem lesions on 10-Hz and 2- to 6-Hz rhythms in sympathetic nerve discharge

We studied the effects of brain stem lesions or transection on the 10-Hz and 2- to 6-Hz rhythms in sympathetic nerve discharge (SND) in baroreceptor-denervated unanesthetized decerebrate cats. The results indicate that these two rhythms depend in part on different brain stem regions. The 10-Hz rhythm was eliminated by ablation of the rostral ventrolateral medulla (RVLM), medullary raphe complex, or pontine parabrachial and Kölliker-Fuse complex (PB/KF) or by pontomedullary border transection. Except for RVLM lesions, these procedures did not disrupt the 2- to 6-Hz rhythm in SND. In fact the power in SND at frequencies less than 6 Hz was increased by raphe or PB/KF lesions. Total power in SND was not significantly affected by raphe or PB/KF lesions, but mean arterial pressure was significantly reduced. Field potentials recorded from the RVLM (11 of 26 sites) and raphe (10 of 20 sites) were correlated to the 10-Hz rhythm in SND, further supporting a role of these areas in either generating or relaying this rhythm to sympathetic nerves. In contrast, field potentials recorded from the PB/KF were not correlated to the 10-Hz rhythm in SND. Thus this region may provide a tonic drive to the 10-Hz generator located elsewhere in the brain stem.

The 10-Hz rhythm in sympathetic nerve discharge

Frequency-domain analysis was used to characterize the relationships among the rhythmic discharges recorded simultaneously from two to four sympathetic nerves in unanesthetized decerebrate cats. The major new findings were as follows. 1) The 10-Hz rhythmic discharges of different nerves cohered strongly in baroreceptor-innervated and -denervated cats. 2) The interval between the discharges of two nerves was frequency dependent in the 10-Hz band in some cats, supporting the view that the 10-Hz rhythm is generated by multiple central circuits that are coupled. 3) In some cases the central circuits responsible for the 10-Hz rhythms nonuniformly affected different nerves. 4) In baroreceptor-innervated cats the coherence values for the cardiac-related discharges of any two nerves were significantly higher than those for the 10-Hz rhythms. 5) In baroreceptor-denervated cats the 10-Hz rhythmic discharges of different nerves cohered more strongly than the 2- to 6-Hz rhythms. 6) The 10-Hz rhythm usually was not a harmonic of the 2- to 6-Hz or cardiac-related rhythm. Thus these rhythms are generated independently.

Glutathione S-transferase mu locus: use of genotyping and phenotyping assays to assess association with lung cancer susceptibility

In mammals, the cytosolic glutathione S-transferases (GSTs; EC 2.5.1.18) are a supergene family comprised of four multigene families, named alpha, mu, pi and theta. In man, within the mu class gene family there is a gene (the GSTmu 1 locus) that is polymorphic and is only expressed in 50-55% of individuals. It has previously been reported, using trans-stilbene oxide (tSBO) as a specific substrate for the expressed phenotype, that smokers with the null phenotype had a greater susceptibility to lung cancer. In a subsequent study, it was shown that on Southern blot analyses of human DNAs using a GSTmu 1 cDNA probe a DNA fragment was absent in certain individuals. The absence of this band correlated with the tSBO null phenotype. In the present work, DNA clones derived from GST mu class genomic sequences were used as probes in Southern blot analyses and confirmed the correlation between the lack of a DNA fragment and the null phenotype; moreover in this case, using radioimmunoassay for the GST mu protein, these probes were then used in a genotyping assay to investigate further the association of GSTmu 1 polymorphism with susceptibility to lung cancer. It was found that in a control group of 225 individuals, of unknown smoking history, 42% lacked the restriction fragment and were homozygous null, and therefore 58% were either heterozygous or were homozygous normal. Among 228 lung cancer patients, which included all tumour types, a similar distribution occurred, namely 43% were homozygous and 57% were heterozygous or homozygous normal. If, however, the tumours were analysed by tumour type a small but significant positive correlation with the homozygous null genotype was seen in squamous carcinoma of the lung, and an apparently negative correlation with adenocarcinoma of the lung.

High power, low frequency components of cardiac, renal, splenic and vertebral sympathetic nerve activities are uniformly reduced by spinal cord transection

Others have reported that spinal cord transection non-uniformly affects the activities of the cardiac, renal and splenic nerves. We were unable to confirm this finding while recording the wide band (1-1000 Hz) discharges of these sympathetic nerves in baroreceptor-denervated, chloralose-anesthetized cats. Most of the power in nerve discharges was below 6 Hz. There was high coherence between the low frequency discharges of different nerves, and power below 15 Hz was essentially eliminated by spinal transection. Evidence is presented that the disparities between this and past studies are, in part, due to the use of a 30-Hz high-pass filter in the earlier studies.

Differential relationships among discharges of postganglionic sympathetic nerves

The relationships among the simultaneously recorded discharges of as many as four postganglionic sympathetic nerves were studied with coherence and phase spectral analyses in baroreceptor-denervated cats. Discharges were recorded from the inferior cardiac (CN), vertebral (VN), and renal (RN) nerves. Most of the power in sympathetic nerve discharge was less than 6 Hz, and the discharges of any two nerves coherred over a frequency band generally between 0 and 15 Hz. Peak coherence occurred between 2 and 6 Hz in most cases. Our most important observations are as follows. 1) Coherence values were significantly higher in chloralose-anesthetized than in unanesthetized decerebrate cats. 2) Coherence values were higher for near ipsilateral nerves (e.g., CN and VN) than for widely separated ipsilateral nerves (e.g., CN and RN). 3) Coherence values for most pairs were higher when the nerves were located on the same side (ipsilateral nerves) rather than on opposite sides (contralateral nerves) of the body. 4) Coherence values were higher for some functionally complementary nerves (e.g., CN and RN) than for noncomplementary nerves (e.g., VN and RN). These results support the hypothesis that the central circuits responsible for the basal discharges of different postganglionic sympathetic nerves are selectively coupled.

Repeated pregnancy without lactation: effects on maternal glycemic control, pregnancy outcome, carcass composition, and fat distribution in rats

Repeated pregnancy without lactation in rats has been reported to produce permanently elevated carcass fat mass and hyperplasia in subcutaneous fat depot. In the present study, the pregnancy outcome, intravenous glucose tolerance ability (IVGTT), and carcass composition were further examined in Osborne-Mendel rats. Female rats were divided into pregnancy-lactation (PL), pregnancy-no lactation (PNL), and control (CON) groups. Half of the rats were killed after three pregnancy/lactation cycles, whereas the rest were given a 12-week rest period before killing. It was found that rats in PNL group had fasting hyperglycemia and insulin insensitivity during the third pregnancy (P less than or equal to .05), elevated spontaneous abortion rate (P less than or equal to .05), and elevated subcutaneous fat content (P less than or equal to .01) relative to that of PL rats or CON rats. After a 12-week rest period, a significant increase in subcutaneous fat cell number was also observed in PNL rats. PL rats, on the other hand, have significantly elevated internal/subcutaneous fat ratios (P less than or equal to .05), both immediately after weaning and after the 12-week rest period. The significance of this change is not yet known.

Role of interleukin 1 and tumor necrosis factor on energy metabolism in rabbits

A study of the combined effects of intravenous infusion of the recombinant cytokines beta-interleukin 1 (IL-1) and alpha-tumor necrosis factor (TNF) on energy substrate metabolism in awake, conditioned, adult rabbits was performed. After a 2-h basal or control period, 48-h fasted rabbits were administered TNF and IL-1 as a bolus (5 micrograms/kg) followed by a continuous intravenous infusion (25 ng.kg-1.min-1) for 3 h. Significant increases in plasma lactate (P less than 0.01), glucose (P less than 0.01), and triglycerides (P less than 0.05) occurred during the combined infusion of IL-1 and TNF, whereas neither cytokine alone had no effect. There was a 33% increase in the rate of glucose appearance (P less than 0.05), but glucose clearance was not altered compared with the control period. Glucose oxidation increased during the combined cytokine infusion period and glucose recycling increased by 600% (P less than 0.002). Lactic acidosis and decreased oxygen consumption, as a result of the cytokine infusions, indicated development of anaerobic glycolytic metabolism. A reduction in the activity state of hepatic mitochondrial pyruvate dehydrogenase (65 vs. 82% in control animals, P less than 0.05) was consistent with the observed increase in anaerobic glycolysis. Thus the combined infusion of IL-1 and TNF in rabbits produces metabolic manifestations seen in severe injury and sepsis in human patients and, as such, may account for the profound alterations of energy metabolism seen in these conditions.

Anatomical analysis of the cause of skin necrosis of the great toe after transplantation of the great toe nail flap

Necrosis of skin on the medial side of the great toe has been a significant complication of the great toe nail flap. To investigate the reason for this, a study of the blood supply of the medial side of the great toe was carried out on 55 feet with the injection of red latex into the arteries and on 13 vascular cast specimens. It was found that, after the blood vessels from the plantar and dorsal sides of the great toe are severed during the operation, the skin of the medial side of the great toe is mainly supplied by the medial vascular network at the head of the first metatarsal bone. It is clear that the blood supply from this network may sometimes be insufficient to nourish the skin. It is suggested that the operative incision should be changed so as to increase the blood supply to the medial vascular network which may decrease the incidence of skin necrosis.

Vallesiachotamine and isovallesiachotamine from the seeds of Strychnos tricalysioides

The alkaloids vallesiachotamine and isovallesiachotamine have been isolated from the seeds of Strychnos tricalysioides and identified on the basis of their spectral characteristics. The potential chemotaxonomic significance of these alkaloids is briefly discussed.