Immunosuppressive activity of chemically synthesized gangliosides

New chemical synthetic methods have permitted the synthesis of a spectrum of glycosphingolipid molecular species, some of which are not naturally occurring. Here we have studied a number of chemically synthesized gangliosides for immunosuppressive activity, using a human in vitro specific antigen (tetanus toxoid)-induced assay of the cellular immune response. Chemically synthesized GM3 and GM4 had the same high degree of immunosuppressive activity as did natural GM3 and GM4 gangliosides, verifying that inhibition is intrinsic to the ganglioside molecules and not caused by other molecules sometimes found in natural preparations (e.g., proteins). Studies of modified molecular species of GM3 and GM4, also prepared by chemical synthesis, have shown the influence of certain structural details upon the immunosuppressive activity of gangliosides: (i) the inverse relationship between fatty acyl chain length and immunosuppressive activity is extended to even shorter chain lengths, with the synthetic gangliosides d18:1-C2:0-GM3 and d18:1-C14:0-GM3 being more immunosuppressive than d18:1-C18:0-GM3 and d18:1-C24:0-GM3; (ii) hydroxylation of the fatty acyl group decreases immunosuppressive activity; (iii) substitution of an S-glycosidic bond for an O-glycosidic bond in the sialic acid ketosidic linkage in GM4 does not alter its activity; and (iv) modifications of the sialic acid group variably influence immunosuppressive activity, since KDN-GM3 and -GM4 ganglioside analogues, which contain a 3-deoxy-D-glycero-D-galacto-2-nonulopyranosonic acid in place of N-acetylneuraminic acid, retain activity, while other modifications such as 8-epi-GM3, and to a lesser extent 9-deoxy-GM3, reduce immunosuppressive activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Human tumor gangliosides inhibit murine immune responses in vivo

Gangliosides which are shed by tumor cells clearly inhibit cellular immune responses in vitro. However, the immunosuppressive activity of these molecules have been more difficult to ascertain in vivo. Here we have adapted a murine model to determine the effects of tumor gangliosides in an in vivo microenvironment, the lymph node draining the site of stimulation by allogeneic cells. In this model, allogeneic splenocytes (BALB/c) are s.c. injected into C3H mice. The cellular immune response in the draining popliteal lymph nodes 4 days later is evidenced as an increase in lymph node mass (2-fold), lymphocyte number (6-fold), and lymphocyte DNA synthesis (6-fold). Purified human neuroblastoma gangliosides (10 nmol) coinjected with the stimulating allogeneic cells significantly suppressed this in vivo immune response. The increase in the lymph node mass was reduced by 65% (0.66 versus 1.89 mg), the increase in lymphocyte number (4.0 x 10(6) cells/node) was almost completely inhibited (1.1 x 10(6) cells/node), and in vitro [3H]thymidine uptake by the lymphocytes recovered in vivo was reduced by 80%. In contrast to the inhibition by tumor gangliosides, liposomes of cholesterol:lecithin were not inhibitory. Thus, tumor gangliosides, specifically, modulate cellular immune responses in vivo, which may contribute to the observed enhancement of tumor formation by these molecules.

Construction and characterization of a human chromosome 2-specific BAC library

We have constructed a human chromosome 2-specific bacterial artificial chromosome (BAC) library using DNA from the somatic cell hybrid GM10826. The average size of the clones is about 63 kb. The coverage and distribution of the library were estimated by screening with known polymorphic genetic markers and fluorescence in situ hybridization (FISH). Twenty-one markers tested positive when DNA pools prepared from approximately one-sixth of the library were screened with 33 known markers. This is consistent with the theoretical calculation of 63% coverage at one genomic equivalent. This suggested that the coverage of the library is approximately 5-6x. FISH analysis with 54 BACs revealed single site hybridization to chromosome 2, and the clones were distributed randomly on the chromosome. We have also performed direct sequencing of the BAC insert ends to generate sequence-tagged sites suitable for mapping and chromosome walking. This is the first reported human chromosome 2-specific BAC library and should provide a resource for physical mapping and disease searching for this chromosome.

[Distribution of ABH substances in normal secretor human tissue cells by avidin-biotin complex method]

The distribution and location of ABH substances in 54 various kinds of normal secretor human tissue cell of known ABO type were studied by Avidin-Biotin complex (ABC) method. It was firstly demonstrated that 18 different kinds of tissue cells contained ABH substances, which were as follows: neuron and nerve fiber, astrocyte, oligodendrocyte, ependyma epithelial cells, epithelial cells of soft meninges, epithelial cells of parotid gland duct, taste bud cells of tongue, acinar and epithelial cells of duct of buccal gland, epithelial cells of rectal mucous membrane gland, regenerated liver cells of hepatocirrhosis, basal cells of stratified aquamous epithelium of epiglottis, spermiogenesis and spermatozoa of seminiferous tubules, epithelial cells of tubuli reti, rete testis and tubuli epididymis, both primary and secondary follicles of ovary and decidua cells of endometrium. Some new phenomena were observed as follows: ABH substances in chief cells more than those in parietal cells of gastric gland, locally distributed ABH positive cells in stratum spinosum of stratified squamous epithelium of skin, segmentally distributed ABH positive cells in pseudostratified ciliated columanal epithelium of epiglottis. The ABH substances were located at the infranuclear and/or supranuclear region and/or brush border of the epithelial cells of submaxillary gland, mosaic distributed ABH substances were found in the epithelia of both sweat and submaxillary glandular ducts. A few controversies about distribution of ABH substances were solved. The relationship between H and A, B substances, origin of ABH substances, source of ABH substances in body fluids. Production of ABH substances and cell differentiation, mosaicism and inconsistency of ABH distribution are discussed and compared with other reports.(ABSTRACT TRUNCATED AT 250 WORDS)

B-mode-detected carotid artery plaque in a general population. Atherosclerosis Risk in Communities (ARIC) Study Investigators

BACKGROUND AND PURPOSE

There is little information on the distribution of atherosclerotic lesions of the extracranial carotid artery wall in free-living populations. The purpose of the present study was to describe the prevalence from 1987 through 1989 of extracranial carotid artery plaque and plaque with acoustic attenuation (shadowing) lesions in a general population of white and black adults from four US communities.

METHODS

B-mode ultrasound was used to characterize wall lesions in the common and internal carotid arteries and at the carotid artery bifurcation in 14,046 men and women 45 to 64 years old who participated in the Atherosclerosis Risk in Communities Study baseline survey.

RESULTS

Thirty-four percent of participants had plaque and 6.4% had plaque with acoustic shadowing. The prevalence of plaque with acoustic shadowing increased steadily with age from 2.5% at ages 45 to 49 to 12.4% at ages 60 to 64. Overall, whites had more plaque with acoustic shadowing lesions than blacks (odds ratio [OR], 1.22; 95% confidence interval [CI], 1.02 to 1.46), and men had more than women (OR, 1.42; 95% CI, 1.22 to 1.63). However, plaque lesions in the common carotid artery were less common among whites than among blacks, and no racial difference was observed in the prevalence of plaque with acoustic shadowing at this segment.

CONCLUSIONS

Although these prevalence rates are likely to be underestimated because of the emphasis on arterial boundary visualization of the scanning protocol, they show a large, mostly asymptomatic burden of atherosclerosis in these populations, especially among older individuals. Site-specific frequency rates of plaque varied between blacks and whites. Among those with plaque, however, whites had more lesions with acoustic shadowing attenuation.

Differential effects by the p21 CDK inhibitor on PCNA-dependent DNA replication and repair

In mammalian cells, DNA damage increases the levels of the nuclear tumour-suppressor p53, resulting in elevated synthesis of p21, an inhibitor of cyclin-dependent kinases (CDK). p21 may also directly block DNA replication by inhibiting the proliferating-cell nuclear antigen (PCNA), an essential DNA replication protein. However, PCNA is also required for nucleotide-excision repair of DNA, an intrinsic part of the cellular response to ultraviolet irradiation. Using an in vitro system, we now show that p21 does not block PCNA-dependent nucleotide-excision repair, in contrast to its inhibition of simian virus 40 DNA replication. Furthermore, the short gap-filling DNA synthesis by PCNA-dependent DNA polymerases delta and epsilon is less sensitive to inhibition by p21 than is long primer-extension synthesis. The ability of p21 to inhibit the role of PCNA in DNA replication but not in DNA repair rationalizes in vivo data showing that genetic damage leads to inactivation of chromosomal replication while allowing damage-responsive repair.

A chemically synthesized sialic acid-containing glycoconjugate, 2-(tetradecylhexadecyl)-O-(5-acetamido-3,5-dideoxy-D-glycero-alpha-D-ga lacto-2-nonulopyranosylonic acid)-(2-->3)-O-beta-D-galactopyrannosyl-(1-->4)-beta-D- glucopyrannoside, is a potent inhibitor of cellular immune responses

Structural variations among gangliosides significantly influence their immunosuppressive activity. By total chemical synthesis, a sialic acid-containing glycoconjugate, 2-(tetradecylhexadecyl)-O-(5-acetamido-3,5-dideoxy-D-glycero-alpha -D-galacto-2-nonulopyranosylonic acid)-(2-->3)-O-beta-D-galactopyrannosyl-(1-->4)-beta-D- glucopyrannoside was synthesized. This glycoconjugate has the same carbohydrate structure as does GM3 ganglioside and a branched alkane in place of ceramide. It markedly inhibits the tetanus toxoid-induced human lymphoproliferative response in vitro (ID90 < 7 microM) and is five-fold more active than d18:1-C18:0 GM3 ganglioside, to which it is structurally related. This glycoconjugate is also a potent inhibitor of the murine alloimmune response in vivo: 10 nmol of the molecule injected subcutaneously together with an allogeneic cell challenge markedly inhibits the cellular immune response in the draining popliteal lymph node. In fact, the effect is quantitatively similar to that of systemically administered cyclosporin A, a well-studied immunosuppressive agent.

Ambiguous pictorial depth cues and perceptions of nonrigid motion in the three-loop figure

The three-loop figure is a two-dimensional (2-D) pattern that generates (mis)perceptions of nonrigid three-dimensional (3-D) structure when rotated about its centre. Such observations have been described as counterexamples to the principle whereby a moving object is presumed to be rigid, provided that a rigid interpretation is possible (ie the 'rigidity constraint'). In the present investigation we demonstrated that stationary three-loop figures exhibit many of the classic properties of multistable/ambiguous figures, with any one of several possible 3-D configurations being reported at any one instant. Further investigation revealed that perceived nonrigidity during rotation was markedly reduced (and rigidity enhanced) when the figure was modified with static pictorial depth cues (eg shading, interposition). These cues had no effect on the overall proportion of time that observers reported 3-D organisations in stationary versions of the figure, but significantly reduced the frequency of perceptual reorganisation, and increased the duration for reporting a particular organisation. Since each of the perceived 3-D structures in a stationary ambiguous 2-D figure has a unique kinetic counterpart (ie rigid transformation), we attribute the nonrigid structure perceived when the figure rotates to the integration of these otherwise inconsistent kinetic components; and have further illustrated this with modified versions of a Penrose impossible triangle. Under kinetic versions of the classical size/distance invariance hypothesis, the rigidity constraint may be considered to represent a special instance of size/shape constancy, in which case counterexamples involving (mis)perceptions of nonrigid structure are comparable to other well-known exceptions to such principles of minimum object change (eg classical illusions).

Anti-malarial drug development using models of enzyme structure

BACKGROUND

The trophozoite stage of the malaria parasite infects red blood cells. During this phase of their life-cycle, the parasites use hemoglobin as their principal source of amino acids, using a cysteine protease to degrade it. We have previously reported a three-dimensional model of this cysteine protease, based on the structures of homologous proteases, and the use of the program DOCK to identify a ligand for the malaria protease.

RESULTS

Here we describe the design of improved ligands starting from this lead. Ligand design was based on the predicted configuration of the lead compound docked to the model three-dimensional structure of the protease. The lead compound has an IC50 of 6 microM, and our design/synthesis strategy has resulted in increasingly potent derivatives that block the ability of the parasites to infect and/or mature in red blood cells. The two best derivatives to date have IC50(s) of 450 nM and 150 nM.

CONCLUSIONS

A new class of anti-malarial chemotherapeutics has resulted from a computational search that was based on a model of the target protease. Despite the lack of a detailed experimental structure of the target enzyme or the enzyme-inhibitor complex, we have been able to identify compounds with increased potency. These compounds approach the activity of chloroquine (IC50 = 20 nM), but have a distinct mechanism of action. This series of compounds could thus lead to new therapies for chloroquine-resistant malaria.

Acidic transcription factors alleviate nucleosome-mediated repression of DNA replication of bovine papillomavirus type 1

The papillomavirus E2 transcription factor is directly involved in viral DNA replication. Previous studies have shown that E2 interacts with both the viral E1 helicase and cellular replication proteins, and thus it may facilitate their targeting to the origin of replication. We demonstrate here that E1-mediated replication of bovine papillomavirus type 1 is repressed by nucleosomal assembly. The E2 protein counteracts this repression, and such activation requires the E2-binding sites adjacent to the origin of replication. These in vitro results are consistent with the previous in vivo findings that both E2 and specific E2 binding to DNA are absolutely required for replication of bovine papillomavirus. Furthermore, the function of E2 in preventing nucleosome-mediated repression can be achieved as well by several other acidic transcription factors. These data therefore strongly support the idea that a group of enhancer proteins may utilize similar mechanisms to stimulate transcription and replication.

Effect of chronic haloperidol treatment on dopamine-induced inositol phosphate formation in rat brain slices

The effects of chronic haloperidol administration on the accumulation of inositol phosphates were examined in rat brain slices pre-labeled with [3H]myo-inositol and incubated with various dopaminergic drugs. Rats were treated with haloperidol-decanoate or its vehicle (sesame oil) for two, four or six weeks. Dopamine and the selective D1 agonist, SKF38393, induced a significant increase in lithium-dependent accumulation of [3H]inositol monophosphate (IP1) in the frontal cortex, hippocampus and striatum of vehicle-treated animals, while the selective D2 agonist quinpirole did not show any effect on IP1 accumulation. The actions of dopamine and SKF38393 were blocked by the D1 antagonist, SCH23390, but not by the D2 antagonist, spiperone, in all three brain regions. Haloperidol treatment did not affect basal phosphoinositide turnover in the three brain regions. Four or six weeks of haloperidol treatment significantly decreased dopamine-induced IP1 accumulation in the striatum (by 30% and 25%, respectively), but not in the frontal cortex and the hippocampus. Four weeks of treatment with haloperidol significantly decreased IP1 levels in the striatal slices when measured in the presence of quinpirole. However, the accumulation of IP1 measured in the presence of SKF38393 was not significantly altered after haloperidol treatment. The loss of dopamine-sensitive IP accumulation was not observed in the presence of spiperone after haloperidol treatment. The number, but not the affinity, of [3H]sulpiride binding sites in the striatum was significantly increased (by 34-46%) after chronic haloperidol treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

[Pharmacological study on Asparagus officinalis Linn]

Our experiment shows that Asparagus officinalis can increase the clearance rate of charcoal particles and the weight of immune organs in mice, and thus helps to facilitate their antifatigue, anoxia tolerance, analgesia and memory improvement, as well as decrease the contents of lipid peroxide (LPO) in plasma, liver and brain of the animal.

Functional consequences of iron supplementation in iron-deficient female cotton mill workers in Beijing, China

Eighty iron-deficient, nonpregnant female workers were randomly assigned to ferrous sulphate (60 or 120 mg Fe/d) or placebo treatment for 12 wk. Energy expenditure was estimated during 3 d by heart rate (HR) recording. Production efficiency (PE) was calculated as the ratio of productivity to energy expenditure. In the iron-treated group mean hemoglobin (Hb) increased from 114 to 127 g/L (P < 0.001), mean serum ferritin increased from 9.7 to 30.0 micrograms/L (P < 0.001), and mean free erythrocyte protoporphyrin decreased from 1.01 to 0.49 mumol/L (P < 0.001). Mean HR at work decreased from 95.5 to 91.1 beats/min (P < 0.001), which was inversely correlated with the change in Hb (r = -0.60, P < 0.001). PE increased significantly in the iron-treated group (P < 0.001) and its change paralleled the change in Hb (r = 0.58, P < 0.001). The results show that iron supplementation enabled these women to do the same work at a lower energy cost.

Ceramide structure predicts tumor ganglioside immunosuppressive activity

Molecular determinants of biological activity of gangliosides are generally believed to be carbohydrate in nature. However, our studies of immunomodulation by highly purified naturally occurring tumor gangliosides provide another perspective: while the immunosuppressive activity of gangliosides requires the intact molecule (both carbohydrate and ceramide moieties), ceramide structure strikingly influences ganglioside immunosuppressive activity. Molecular species of human neuroblastoma GD2 ganglioside in which the ceramide contains a shorter fatty acyl chain (C16:0, C18:0) were 6- to 10-fold more active than those with a longer fatty acyl chain (C22:0/C24:1, C24:0). These findings were confirmed in studies of ceramide species of human leukemia sialosylparagloboside and murine lymphoma GalNAcGM1b. Gangliosides that contain shorter-chain fatty acids (and are most immunosuppressive) are known to be preferentially shed by tumor cells. Therefore, the results suggest that the tumor cell is optimized to protect itself from host immune destruction by selective shedding of highly active ceramide species of gangliosides.

[Preliminary results of three different cannulations for percutaneous transhepatic cholecystic drainage in the interventional gallstone dissolutions]

Three different methods of percutaneous transhepatic gallbladder cathetering drainage were applied in 33 patients undergoing interventional gallstone dissolution. Among them, sheathed needle was used in 6 cases with a success rate of 33%; wire-guided in 16 with a success rate of 50%; and double-sheathed inner needle was successfully used in all the 11 cases. The authors believe that this last method could safely be used in the nonoperative drainage of acute cholecystitis as well as the interventional gallstone dissolutions.

[Gas chromatographic method with EC detection to determine isosorbide-5-mononitrate (IS-5-MN) in human serum and its pharmacokinetic parameters]

A simple, sensitive and precise capillary GC-ECD method was developed for the determination of isosorbide-5-mononitrate in human serum. Pharmacokinetic parameters of the drug was obtained from the human serum level-time curve measured. Serum samples were extracted with a mixture of ethyl ether-ethyl acetate (4:1), the upper phase was collected and evaporated to about 100 microliters under a gentle nitrogen stream. Isosorbide dinitrate was used as internal standard. With a human serum sample size of 200 microliters, the detection limit of IS-5-MN was found to be about 5 ng/ml, and the absolute recovery from 74% to 85%. The within-day and between-day relative standard deviation were less than 7% and 9%, respectively. This method was applied to the pharmacokinetic studies of IS-5-MN tablets from two different sources. Two sets of t1/2 (Ke), Tmax and AUC values obtained from 8 volunteers were tested statistically and no significant difference was found.

A preliminary analysis of divorce in China

"With data from the 1982 and 1990 censuses and data of divorce from civil administration departments, it is possible to make a preliminary analysis on changes in the number of divorces and the population of divorcees in China since the 1980s." Aspects considered include regional differentials, sex differences, age patterns, and remarriage.

Modulation of human myelopoiesis by human gangliosides

Cell surface gangliosides are potent modulators of cellular proliferation. We hypothesize that gangliosides shed by tumor cells modulate hematopoiesis and contribute to human tumor-associated suppression of hematopoiesis. To test this hypothesis, we determined the effects on myeloid colony formation by human bone marrow mononuclear cells of total gangliosides isolated from human brain and of seven highly purified individual ganglioside species (GM1, GM2, GD1a, GD1b, GD2, GD3, and GT1b). Total human brain gangliosides and certain individual species, GD1a, GD1b, and GT1b, significantly inhibited myeloid colony formation (number as well as size). The most complex molecules, GD1a, GD1b, and GT1b, were the most inhibitory, suggesting that the degree of inhibition is related to ganglioside structural complexity. To extend these findings, we also investigated certain tumor-derived (neuroblastoma) gangliosides, which we found inhibited both myeloid colony formation and 3H-thymidine incorporation by human bone marrow mononuclear cells. These data suggest a role for gangliosides, which are shed by proliferating cells, in the regulation of human hematopoiesis and may explain the bone marrow hypoplasia observed in association with many human malignancies.

Enhancer activity of light-responsive regulatory elements in the untranslated leader regions of cyanobacterial psbA genes

Three psbA genes encoding the D1 protein of the photosystem II reaction center are differentially expressed under different light intensities in the cyanobacterium Synechococcus sp. strain PCC 7942. Two of the three psbA genes, psbAII and psbAIII, are induced rapidly when light intensity is increased from 125 x 10(-6) mol.m-2.s-1 to 750 x 10(-6) mol.m-2.s-1. A recombinational cloning vector that carries a transcriptional lacZ reporter gene was used to characterize the controlling elements responsible for light induction. At least three distinct cis elements are present in the regulatory regions of pbsAII and psbAIII: basal promoters, comparable to Escherichia coli sigma 70 promoters in position and sequence, confer constitutive expression of the genes under both low and high light intensities; negative elements upstream of the promoters down-regulate the expression of the corresponding gene; and sequences downstream of the promoters that correspond to the untranslated leader regions of the mRNAs (+1 to +41 in psbAII and +1 to +39 in psbAIII) are responsible for increased expression under high light. When these light-responsive elements were combined with an E. coli promoter (conII) in different positions and orientations, the expression of the lacZ gene was induced 4- to 11-fold. The induction of gene expression under high light by these enhancers was position independent but orientation dependent. When the elements were combined with the conII promoter in the correct orientation, they also conferred a small but reproducible level of light-responsive expression on this E. coli promoter.

Inadequate treatment of pain in ambulatory HIV patients

OBJECTIVE

To evaluate the prevalence of pain, how pain affects patients' lives, what treatments are being used, and the effectiveness of these pain treatments in ambulatory patients with human immunodeficiency virus (HIV) disease.

DESIGN

A self-administered pain survey (modified version of the Wisconsin Brief Pain Questionnaire).

SETTING

An ambulatory infectious disease clinic that deals mainly with ambulatory HIV patients.

PATIENTS

Ambulatory HIV patients.

OUTCOME MEASURES

Results of the response to the questionnaire.

RESULTS

Eighty-two of 148 patients surveyed had pain due to their disease in the month prior to completing the survey. Of those reporting pain, 60-70% reported that their pain interfered with aspects of their daily lives from a moderate to severe degree. In patients with pain, 40% reported that they were not receiving any pain treatment. Those patients who were receiving treatment only obtained a mean pain relief of 65%.

CONCLUSIONS

Pain is an important problem in terms of its prevalence and impact on patients with HIV disease. Pain control in this patient population is inadequate. Clinicians should realize that pain can be present regardless of the duration of the disease and its severity. Patients need to be educated about the proper use of pain medications and helped to understand that pain medications will not "worsen their disease."

The mitotic feedback control gene MAD2 encodes the alpha-subunit of a prenyltransferase

The mad2-1 mutation inactivates the cell-cycle feedback control that prevents budding yeast cells from leaving mitosis until spindle assembly is complete. The gene product of MAD2 shows significant sequence similarity to the alpha-subunit of prenyltransferases. Here we isolate a new temperature-sensitive mad2 mutant, mad2-2ts, and find that Mad2p is required for the membrane association of Ypt1p and Sec4p, two prenylated small GTP-binding proteins involved in protein trafficking. Extracts from mad2-2ts mutant cells fail to geranylgeranylate a number of substrates at the non-permissive temperature. mad2-2ts is synthetically lethal with bet2-1, a mutation in the gene that encodes for the beta-subunit of the Ypt1p and Sec4p geranylgeranyl transferase. Therefore MAD2 and BET2 gene products may physically interact to form a geranylgeranyl transferase complex. In addition, the difference between the phenotypes of mad2-1 and mad2-2ts suggests that MAD2 has distinct roles in protein transport and the mitotic feedback control.

Biosynthesis and shedding of murine lymphoma gangliosides

Ganglioside biosynthesis and subsequent shedding are a potential mechanism contributing to tumor cell escape from the host immune response. As a first step in identifying active molecular species, structural characterization and quantification of the purified individual cellular and shed gangliosides of YAC-1 murine lymphoma cells were undertaken. These studies uncovered three striking changes in ganglioside metabolism in cells passaged in vivo, compared with cells cultured in vitro. (i) Marked inhibition of GalNAcGM1b synthesis: GM1b was present in an equal proportion to its biosynthetic product GalNAcGM1b in vitro, but was present in a 6-fold higher concentration in vivo. (ii) Marked inhibition of NeuGc synthesis: NeuGc, present in vitro in an up to 7-fold higher concentration than its biosynthetic precursor NeuAc, was decreased in relative concentration in vivo (1:1). (iii) Selectivity of shedding: ganglioside shedding in vitro was generalized with respect to both carbohydrate structure and ceramide structure (mainly d18:1-C24:1 and d18:1-C16:0), while in vivo, there was selective shedding of gangliosides containing NeuGc and the shorter chain fatty acid. The reduced synthesis of NeuGc and of GalNAcGM1b in vivo, and the selective shedding of more polar ganglioside species, also in vivo, show that the extracellular environment can markedly affect cellular ganglioside metabolism.

Prevalence and type of anaemia in female cotton mill workers in Beijing, China

The present study investigates the prevalence and type of anaemia in Chinese female cotton mill workers. The prevalence of anaemia is reported in 447 non-pregnant female workers aged between 19 and 45 years. The mean value for haemoglobin (Hb) was 123 (SD 15) g/l and 150 of the total 447 subjects had Hb values below 120 g/l; thus 34% of the population was anaemic according to World Health Organization (WHO, 1975) criteria. The mean value for free erythrocyte protoporphyrin (FEP) was 419 (SD 215) micrograms/l; 55% of the total population had FEP values higher than 350 micrograms/l and 72% among the anaemic subjects. Serum ferritin (SF) was tested in all the women with a Hb value less than 120 g/l and 71% of them had SF values below 12.0 micrograms/l. Eighty women diagnosed as either Fe deficient or with Fe-deficient anaemia were selected for a diagnostic supplementation trial. They were randomly assigned to FeSO4 (60 or 120 mg Fe/d) or placebo treatment for 12 weeks. Fe supplementation increased mean Hb values from 114 to 127 g/l (P < 0.001) and SF levels from 9.7 to 30.0 micrograms/l (P < 0.001), and decreased mean FEP values from 570 to 277 micrograms/l (P < 0.001). The response rate of Hb in the whole Fe-treated group or Fe-treated subjects with an Hb level less than 120 g/l was 90% or 92% respectively. These findings indicate that the type of anaemia in this population was mainly Fe deficiency. It was also found that in this population the severity of anaemia, not the prevalence, was significantly related to the use of intra-uterine devices (IUD).

A critical evaluation of heart rate monitoring to assess energy expenditure in individuals

The prediction of energy expenditure (EE) from minute-by-minute heart rate (HR) recording was evaluated in 40 female workers, with emphasis on the inter- and intraindividual variation of this method. The results show that the relationship between EE and HR varied greatly between and within subjects. The inter- and intraindividual CVs were 14-18% and 11-20%, respectively. The poor limits of agreement in EE (mean difference +/- 2 SD) between group and individual calibration curves indicate that estimated EE from group curves is inferior to estimated EE from individual curves. Therefore, it is concluded that to have the best estimates of individual EE, only individual calibration curves should be used. At different occasions these curves should be generated again. Because the limits of agreement in EE between individual curves based on 18 and 9 different activities were wide (-2399 to 1817 kJ/16 h), it is preferable to have a wide range of different activities in the individual calibration procedure.

Erythrocyte adenosine transport. A rapid screening test for cardiovascular drugs

An erythrocyte (RBC) model based on whole blood was used to investigate the effect of cardiovascular drugs on the uptake of adenosine in vitro. Fresh whole blood obtained from healthy volunteers was allowed to equilibrate with various concentrations (5-1000 microM) of a tested agent. (2-3H)-Adenosine was used as a substrate, and the reaction was terminated after 2 sec of incubation at room temperature by rapid addition of a "Stopping Solution" which was a mixture of erythro-9-(2-hydroxy-3-nonyl)adenine, dipyridamole, and EDTA. The mixture was centrifuged (1760 g, 4 degrees C, 10 min), and the radioactivity of an aliquot of the supernatant was determined by a scintillation counter. The results showed that dipyridamole was the most potent agent tested (IC50 = 0.2 microM). Amongst the calcium antagonists studied, isradipine was most potent, followed by verapamil, clentiazem, diltiazem, and then nifedipine. The racemates of two metabolites of diltiazem, MX and MB, were more potent than the parent drug. The antiarrhythmic agents, amiodarone and sotalol, the two new lipid peroxidation inhibitors, U-74389F and U-78517F, and the anxiolytic agent, alprazolam, were as active as verapamil. The beta-receptor antagonist propranolol and the angiotensin converting enzyme (ACE) inhibitor, enalapril, were practically inactive. In addition, the model was stereoselective such that the S(-)-enantiomer of verapamil was considerably more potent than the R(+)-antipote, whereas d(+)-sotalol was practically inactive compared to racemic sotalol.

A leukocyte integrin binding peptide from intercellular adhesion molecule-2 stimulates T cell adhesion and natural killer cell activity

Adhesion is of pivotal importance for a number of leukocyte functions. Little is known about the binding between leukocyte integrins and the intercellular adhesion molecules (ICAMs). Normally integrins are nonadhesive, and require a stimulus to become active. We have now identified a peptide from ICAM-2, which binds to leukocyte integrins and activates adhesion. Furthermore, the peptide strongly increased the binding and cytotoxicity of natural killer cells. These findings show that adhesion-dependent leukocyte functions can be activated by ligand-derived peptides, and therefore provide evidence that the avidity of leukocyte integrins is up-regulated by integrin-ligand interactions.

Effects of haloperidol, lithium, and valproate on phosphoinositide turnover in rat brain

The effects of acute, subacute, and chronic treatment with haloperidol, lithium, and valproate on inositol phosphate (IP) formation were examined. Acute treatment with haloperidol or the combination of haloperidol and lithium significantly reduced IP basal cortical levels. Subacute (three days) treatment with lithium decreased the IP basal level in the frontal cortex. Chronic treatment with haloperidol (14 and 28 days) caused a significant attenuation of carbachol-sensitive IP accumulation in the frontal cortex and striatum and a significant decrease in norepinephrine (NE)-induced IP formation in the frontal cortex (14 and 28 days) and striatum (28 days). Lithium treatment for 14 days produced a significant reduction in the IP basal cortical value, and a significant reduction in cortical carbachol- and NE-induced IP formation was found after 28 days of lithium treatment. The combination of haloperidol and lithium for 28 days decreased the striatal carbachol- and cortical NE-induced IP accumulation and caused a significant increase in NE-sensitive IP formation in the striatum at 14 days. Valproate treatment for 28 days was associated with a significant attenuation in striatal agonist-stimulated IP formation. Therefore, three drugs with different specificities for primary neurotransmitters may have common effects on second-messenger systems.

Expression of bone protein mRNA at physiological fluoride concentrations in rat osteoblast culture

Fluoride causes an increase in the amount of unmineralized osteoid. To determine whether the increase in osteoid is due to greater protein expression in the presence of fluoride, we measured the relative amount of mRNA expressed by fetal rat calvaria cells maintained in culture for either 18 or 26 days in the presence of 0, 5, 20 or 300 microM fluoride. There were no differences in the level of expression of mRNA for collagenous or non-collagenous proteins in fluoride-treated cells as compared with control cells at 18 days in culture. Expression of mRNA for osteocalcin and alpha 1-type 1 collagen was decreased at 300 microM fluoride after 26 days culture. The amount of [3H]thymidine incorporation in cells exposed to the different amounts of fluoride was measured at various time points. Fluoride did not alter the time at which rapid cell proliferation ended. These studies indicate that at physiological serum levels, fluoride does not increase expression of mRNA by osteoblasts. The relative increase in osteoid in bone may be related to other mechanisms such as altered matrix mineralization.

A peptide from ICAM-2 binds to the leukocyte integrin CD11a/CD18 and inhibits endothelial cell adhesion

Numerous leukocyte functions depend on adhesive intercellular interactions. The leukocyte-specific integrins CD11a/CD18 (lymphocyte function-associated antigen-1 (LFA-1)) and CD11b/CD18 (complement type 3 receptor (Mac-1)), which bind to the intercellular adhesion molecules ICAM-1 and ICAM-2, play a key role in adhesion. Little is known about the binding in molecular detail. We have now defined a peptide region from the first immunoglobulin domain of ICAM-2 that is specifically involved in binding to CD11a/CD18. A synthetic peptide from this part of ICAM-2, covering residues 21-42, bound to purified CD11a/CD18 and inhibited the adhesion of endothelial cells to this integrin. It also inhibited the binding of B lymphoblastoid cells to endothelial cells. Leukocytes bound to the peptide coated on plastic. Several shorter peptides from the same region showed less or no activity.

The acidic transcriptional activation domains of VP16 and p53 bind the cellular replication protein A and stimulate in vitro BPV-1 DNA replication

For papillomavirus DNA replication, the E2 enhancer protein cooperatively assists in binding of the E1 helicase to the origin. We report that, at limiting E1 and E2 levels, the enhancer proteins GAL4-VP16 and GAL4-p53(1-73) stimulate BPV in vitro DNA replication. This cell-free system was used to ascertain whether the acidic activation domains have a cellular target important for replication. Cellular extracts were depleted of replication activity by passage through a VP16 affinity column. The protein depleted was the cellular factor replication protein A. The direct interaction between replication protein A and VP16, as well as the activation of replication by VP16, is dependent upon the C-terminus of the VP16 activation domain. E2 and the activation domain of p53 also interact with replication protein A. We suggest that a link between transcription and replication involves factors that help convert a closed DNA complex to an open complex.

Comparison of body composition assessments by bioelectrical impedance and by anthropometry in premenopausal Chinese women

Fat-free mass (FFM) was estimated in forty-seven premenopausal Chinese women, aged 18-43 years, from anthropometric data (skinfolds, body mass index (weight/height2; BMI)) or bioelectrical impedance, using several prediction formulas for body composition from the literature, and values compared with the mean of these three individual methods used as a frame of reference. In thirty-six women these values could be compared with FFM calculated from total body water (TBW) determined by D2O dilution. The prediction formulas used were developed from studies on Caucasian adults and their validity will have to be shown in populations with different ethnic backgrounds. The mean difference between FFM predicted from BMI and the frame of reference was 0.1 kg (95% confidence interval (CI) -0.1, 0.4), from bioelectrical impedance it was 0.5 kg (95% CI 0.3, 0.7), and from skinfolds it was -0.6 kg (95% CI -0.9, -0.4). The mean difference between FFM calculated from TBW and the frame of reference was higher (2.2 kg, 95% CI 1.2, 3.3). The results of the present study indicate that the three methods may be valid for predicting body composition in adult Chinese females, but further research is needed on development and cross-validation of prediction equations for body composition for Chinese.

Pharmacokinetics and metabolism of diltiazem in healthy males and females following a single oral dose

Plasma concentrations and urinary excretion of DTZ and its metabolites were determined in 20 healthy volunteers (10 males and 10 females) after they had each been given a single oral 90 mg dose of DTZ. DTZ and six of its metabolites which included N-monodesmethyl DTZ (MA), deacetyl DTZ (M1), deacetyl N-monodesmethyl DTZ (M2), deacetyl O-desmethyl DTZ (M4) and deacetyl DTZ N-oxide (M1NO) and deacetyl N,O-didesmethyl DTZ (M6), were determined by a sensitive and specific HPLC assay. The major metabolites measurable in the plasma of all the volunteers were MA, M1, and M2. The terminal half-lives (t1/2) of M1 and M2 were considerably longer than those of DTZ and MA. Less than 5% of the dose was excreted as unchanged DTZ in the urine over the 24 h period. The major urinary metabolite was MA, followed by M6, M2, and then M1. Except for the urinary excretion of M4 there were no statistically significant differences in any of the pharmacokinetic parameters between the males and the females. The mean 24 h urinary recovery of M4 was higher in the males than in the females (P < 0.05). However there were large inter-individual variations in the plasma concentrations and urinary excretion of DTZ and its metabolites with some parameters differing by more than 20-fold. In addition, O-desmethyl DTZ (Mx) and N,O-didesmethyl DTZ (MB) were identified as two other major urinary metabolites.

Is the Na(+)-K(+)-ATPase the link between phosphoinositide metabolism and bipolar disorder?

Recent experimental work suggests involvement of the phosphatidyl inositol second messenger system in the biochemical mechanism of lithium action, but this work has not shed light on the pathophysiology of bipolar illness. Earlier work had established reduction in sodium-potassium-activated adenosine triphosphatase (Na(+)-K(+)-ATPase) activity as a consistent marker of mood in bipolar illness but had only partially illuminated mechanisms of the action of lithium. Now, advances from research in diabetic neuropathy suggest that inositol phosphate and diacylglycerol metabolism are indeed linked to Na(+)-K(+)-ATPase activity. The data are compatible with a model in which a primary decrease in Na(+)-K(+)-ATPase activity in bipolar patients can stimulate an increase in phosphoinositide hydrolysis, thereby generating the equivalent of a second messenger signal in the absence of a first message. Lithium appears to act by blocking this false second message.

Management of major arterial injuries of the limbs in 166 cases

The charts of 166 patients with major arterial injuries (175 arterial repairs) inflicted during periods of peace and war time were reviewed. One hundred and sixty-seven (95%) of the arteries repaired remained patent. Nine patients had limbs which developed ischemic contracture. Nine patients required amputations. Follow-up data was obtained from seventy-five patients with an average follow-up of five years and one month (six months to thirty years). Early diagnosis, prompt treatment including fasciotomies when indicated, complete debridement, appropriate coverage, meticulous surgical technique, and simultaneous treatment of concomitant injuries are all crucial factors in successful limb salvage. Major arterial injuries of the limb occur frequently in our patient population, especially in time of war. Successful treatment of major arterial injuries may be life-saving, as well as allowing limb salvage and restoration of limb function. The purpose of this study is to review our experience with repair of major arterial injuries.

[Morphology and delta-endotoxin proteins of Bacillus thuringiensis from soils and their toxicities to insects]

94 strains of Bacillus thuringiensis were isolated from soils in southwest and northwest of China. The morphology of cells, spores and parasporal crystals of these strains was investigated under transmission and scanning electro-microscope. Proteins of delta-endotoxins from all strains were analysed by rapid SDS-PAGE. 9 species of insects in Lepidoptera, Coleoptera and Diptera were tested for assay of delta-endotoxins. Some kinds of parasporal crystals were quite different in form and in composition of protein from those reported before. Most of strains were nontoxic to all of 9 species used in bio-assay. Some strains were very effective in species of Coleoptera or Noctuidae.

Alteration of neuroblastoma ganglioside metabolism by retinoic acid

Cellular differentiation is often associated with striking changes in ganglioside metabolism. Because retinoic acid causes cellular differentiation in vitro, we have characterized its effect on ganglioside synthesis and shedding by LAN-5 human neuroblastoma cells. Three major observations were made: (a) 20 microM retinoic acid caused a marked (twofold) increase in cellular ganglioside content, with a slight relative enhancement in GD1a and GT1b synthesis, (b) ganglioside shedding increased in parallel with increased cellular ganglioside content, and also, unexpectedly, (c) retinoic acid caused a quantitatively similar increase in content of cell membrane phospholipids, which are also shed. We conclude that enhanced ganglioside synthesis and shedding by retinoic acid are part of a previously undescribed generalized stimulatory effect on membrane lipid metabolism.