Gastrointestinal tract complications of nonsteroidal anti-inflammatory drug treatment in rheumatoid arthritis. A prospective observational cohort study

BACKGROUND

Gastrointestinal tract (GI) complications associated with nonsteroidal anti-inflammatory drug (NSAID) use are the most common serious adverse drug reactions in the United States. Nonsteroidal anti-inflammatory drugs cause both minor GI side effects such as abdominal pain and vomiting and serious GI events such as ulcers and bleeding. This study evaluates the event rates for all NSAID-induced GI complications in patients with rheumatoid arthritis, describes the time course of these events, and evaluates the role of prophylactic therapy with antacids and H2 receptor antagonists.

METHODS

We studied 1921 patients with rheumatoid arthritis from 8 ARAMIS (Arthritis, Rheumatism, and Aging Medical Information System) centers. Patients were selected for the study if they were treated with NSAIDs and had at least 2.5 years of observation available. Information on GI complications attributed to NSAIDs was obtained from validated patient self-reports collected every 6 months and supplemented by review of hospital records for all hospitalizations.

RESULTS

Approximately 15% of the 1921 patients reported an NSAID-induced GI side effect during the 2.5 year observation period. Forty-two patients had a serious GI complication requiring hospitalization; 34 of these 42 patients did not have a preceding GI side effect. Patients who were taking antacids and H2 receptor antagonists did not have a significantly lower risk for serious GI complications than did those not taking such medications. Asymptomatic patients taking these medications had a significantly higher risk for GI complications compared with those who did not take these medications (standardized odds ratio, 2.14;95% confidence interval, 1.06-4.32).

CONCLUSIONS

A large majority of patients with serious GI complications do not have preceding mild side effects. Prophylactic treatment with antacids and H2 receptor antagonists is of questionable value and may increase the risk for subsequent serious GI complications.

A misfolded form of 5S rRNA is complexed with the Ro and La autoantigens

In both vertebrate and invertebrate cells, the 60-kDa Ro autoantigen is bound to small cytoplasmic RNAs known as Y RNAs. In Xenopus oocytes, the 60-kDa Ro protein is also complexed with a class of 5S rRNA precursors that contain internal mutations. Because these 5S rRNA precursors are processed inefficiently and degraded eventually, the Ro protein may function in a quality control pathway for 5S rRNA biosynthesis. We have investigated the sequence and secondary structure determinants in the mutant 5S rRNAs that confer binding by the 60-kDa Ro protein. The mutant 5S rRNAs fold to form an alternative helix that is required for recognition by the 60-kDa Ro protein. Mutations that disrupt the alternative helix eliminate Ro protein binding, whereas compensatory changes that restore the helix are bound efficiently by the Ro protein. When the structure of the mutant RNA was probed using dimethylsulfate and oligonucleotide-directed RNase H cleavage, the results were consistent with the formation of the alternative structure. The La protein, which is also complexed with the mutant 5S rRNA precursors, protects similar sequences from nuclease digestion as does the 60-kDa Ro protein. Thus, the binding sites for these two proteins are either nearby on the RNA, or the two proteins may be complexed through protein-protein interactions. When the human Ro protein is expressed in the yeast Saccharomyces cerevisiae, the protein binds wild-type 5S rRNA precursors, suggesting that a population of wild-type precursors also folds into the alternative structure.

Effects of divalproex sodium on amitriptyline and nortriptyline pharmacokinetics

BACKGROUND

Divalproex sodium has been found to be efficacious in the prophylaxis of migraine headaches and the management of the manic phase of bipolar syndrome. Because amitriptyline is also prescribed in these patient populations, data are needed on their potential for interaction.

METHODS

The effect of concomitant administration of divalproex sodium on the pharmacokinetics of amitriptyline and its active metabolite, nortriptyline, was investigated in an open-label, sequential, two-period phase I study. Ten healthy male and five healthy female subjects received 50 mg amitriptyline hydrochloride on two occasions: (1) alone (period 1) and (2) 2 hours after receiving the ninth dose of 500 mg divalproex sodium (Depakote) administered once every 12 hours (period 2).

RESULTS

Amitriptyline area under the curve was increased 31% from the combined effect of decreased first-pass metabolism and inhibition of systemic metabolism. The elevated nortriptyline plasma levels reflected primarily the increase in amitriptyline concentrations but also appeared to involve modest inhibition of nortriptyline elimination. For the sum of amitriptyline and nortriptyline concentrations, the peak plasma concentration mean was 19% higher with concomitant divalproex dosing. The mean area under the curve for the sum of amitriptyline and nortriptyline concentrations was 42% higher with concomitant divalproex dosing than it was for dosing with amitriptyline alone.

CONCLUSION

These results suggested that a lower dose of amitriptyline might be considered when divalproex is administered concomitantly.

Promoter-specific activation of mouse lactoferrin gene by epidermal growth factor involves two adjacent regulatory elements

The mouse lactoferrin gene responded to forskolin, 12-O-tetradecanoyl phorbol-13-acetate, and epidermal growth factor (EGF) stimulation via two adjacent enhancer elements, the cAMP response element (CRE) and EGF response element (EGFRE), collectively referred to as the mitogen response unit. In this report, we examined the minimal promoter and enhancer elements of the mouse lactoferrin gene that are required for EGF-induced transcriptional activation. We found that the CRE and noncanonical TATA box (ATAAA) are the minimal promoter elements for basal activity of the chloramphenicol acetyltransferase (CAT) reporter construct whereas the EGFRE is needed for an additional activity induced by EGF in transiently transfected human endometrial carcinoma RL95-2 cells (RL95-2). The EGFRE, however, did not function in heterologous promoters [SV 40 and thymidine kinase (TK)]. Therefore, EGF-stimulated lactoferrin gene activity is promoter specific in RL95-2 cells. In transiently transfected cells, EGF and forskolin showed synergistic effects on the CAT reporter that contained both response elements. Mutation made at either element or insertion of extra nucleotides between the two elements severely affected EGF-stimulated activity. Nuclear protein prepared from RL95-2 cells formed three complexes (A, B, and C) with the oligonucleotides containing both EGFRE and CRE in electrophoretic mobility shift assay. A new complex (E) was detected with the nuclear protein of EGF-treated cells. By oligonucleotide competition experiments, we demonstrated that the complex E was generated by protein bound to CRE. EGF-induced binding activity could be abolished by calf intestinal alkaline phosphatase but not by the protein synthesis inhibitor, cycloheximide. Therefore, binding of a preexisting phosphoprotein to the CRE region could be one of the requirements for EGF-induced mouse lactoferrin gene promoter activity.

[Effect of interferon-gamma on antigen-induced eosinophil infiltration in mouse airway]

Repeated aerosolized ovalbumin (OVA) challenge of OVA-sensitized mice induces bronchoalveolar lavage fluid (BALF) eosinophilia. The influence of interferon-gamma (IFN-gamma) on antigen-induced eosinophil recruitment in the airway as well as the concentration of interleukin-5 (IL-5) in supernatants of cultured spleen cells were examined. In sensitized mice challenged with OVA 20 minutes once a day for 6 days, the number of BALF eosinophils was (9.53 +/- 0.84) x 10(8)/L. However, no eosinophil could be found in the BALF from mice without OVA sensitization and challenge. In mice treated with intraperitoneal injection of INF-gamma before each challenge, different doses of IFN-gamma (1.0 x 10(3) U/kg, 1.0 x 10(4) U/kg and 1.0 x 10(5) U/kg) produced different degrees of eosinophilia inhibition 29.8% (P < 0.05), 55.7% (P < 0.01) and 69.0% (P < 0.01). Our results showed that IFN-gamma prevented antigen-induced eosinophil infiltration in airway accompanied by a decrement of levels of IL-5 with a dose related response. It is concluded that IFN-gamma is capable of inhibiting eosinophil infiltration in mouse airway by inhibiting the production of IL-5. Our results suggested that IFN-gamma may be of value in eliminating asthmatic airway inflammation in humans.

Children's memories in the wake of Challenger

OBJECTIVE

The Challenger spacecraft explosion of Jan. 28, 1986, offered an opportunity to study the memories of normal latency and adolescent children of different emotional involvements following one sudden and distant disaster. How would children of various levels of concern express their memories? And if studied over time, how would these narratives change? Would there be developmental differences? And would there be false details of memory?

METHOD

The authors set out to compare the memories of 153 children from Concord, N.H. (who watched the explosion on television), and Porterville, Calif. (who heard about it). The structured-interview responses of involved and less involved children; latency-age versus adolescent children; and those seen initially (5-7 weeks after the explosion) versus those same children seen later (at 14 months) were statistically compared.

RESULTS

The vast majority of children's memories of Challenger were clear, consistent, and detailed, with highlighting of personal placement, who else was there, and personal occurrences linked to the event. Those children who were less emotionally involved demonstrated significantly less clarity, consistency, and correct ordering of sequences and were less likely to remember personal placement, other people who were there, and related personal incidents. About 30% of all children in this study misunderstood something about Challenger and incorporated these misunderstandings into their memories as false details. Latency-age children continued to harbor false details for 14 months, as opposed to the adolescents.

CONCLUSIONS

Childhood memories of the Challenger space shuttle explosion appeared predictable, were related to patterns of memory that have been observed following single, unrepeated traumas, and reflected age and stage differences.

Estrogen-related receptor, hERR1, modulates estrogen receptor-mediated response of human lactoferrin gene promoter

We have shown previously that estrogen-stimulated transcription from the human lactoferrin gene in RL95-2 endometrium carcinoma cells is mediated through an imperfect estrogen response element (ERE) at the 5 -flanking region of the gene. Upstream from the ERE, a DNA sequence (-418 to -378, FP1) was selectively protected from DNase I digestion by nuclear extracts from endometrial and mammary gland cell lines. In this report, using the electrophoresis mobility shift assay, site-directed mutagenesis, and DNA methylation interference analyses, we show that three different nuclear proteins bind to the FP1 region (C1, C2, and C3 sites). The nuclear receptor, COUP-TF, binds to the C2 site. Mutations in the C1 binding region abolish C1 complex formation and reduce estrogen-dependent transcription from the lactoferrin ERE. When the imperfect ERE of the lactoferrin gene is converted to a perfect palindromic structure, the enhancing effect of the C1 binding element for estrogen responsiveness was abolished. We isolated a complementary DNA (cDNA) clone from an RL95-2 expression library that encodes the C1 site-binding protein. The encoded polypeptide maintains 99% amino acid identity with the previously described orphan nuclear receptor hERR1. A 2.2-kilobase mRNA was detected in RL95-2 cells by the newly isolated cDNA but not by the first 180 base pair of the published hERR1 sequence. By Western analysis, a major 42-kDa protein is detected in the RL95-2 nuclear extract with antibody generated against GST-hERR1 fusion protein. Finally, we show that the hERR1 interacts with the human estrogen receptor through protein-protein contacts.

Effect of interferon-gamma on antigen-induced eosinophil infiltration into the mouse airway

OBJECTIVE

To investigate whether murine recombinant interferon-gamma (IFN-gamma) is capable of inhibiting antigen-induced eosinophil (EOS) infiltration into the mouse airway.

MATERIALS AND METHODS

BALB/c mice were sensitized and challenged repeatedly with ovalbumin (OVA) to develop an allergic airway inflammation model. The experimental mice were given injection of different doses of IFN-gamma. The numbers of EOS in bronchoalveolar lavage fluid (BALF) from each group were counted, and concentrations of interleukin (IL)-5 in supernatants of cultured spleen cells were detected.

RESULTS

In sensitized mice challenged with OVA 20 minutes once a day for 6 days, the number of BLAF EOS was 9.53 +/- 0.84 x 10(5)/ml. However, no EOS could be found in BALF from mice without OVA sensitization and challenge. In mice treated with IFN-gamma, doses of IFN-gamma (1.0 x 10(3), 1.0 x 10(4), 1.0 x 10(5)U/KG) produced 29.8% (P < 0.05), 55.7% (P < 0.01), and 69.0% (P < 0.01) inhibition of eosinophilia, respectively. The results also showed that IFN-gamma prevented antigen-induced EOS recruitment into airway accompanied be decrement of levels of IL-5 with a dose-related response.

CONCLUSION

IFN-gamma is capable of inhibiting EOS infiltration into mouse airway by inhibiting the production of IL-5. Our results suggested that IFN-gamma may be of value in treating asthma in human beings.

Effects of calcium on the migration and recruitment of macrophages and macrophage-derived foam cells

Calcium is thought to play an important role in the genesis of atherosclerotic lesions, but the precise mechanisms involved are unclear. In the present investigation, we have used in vitro systems to investigate the effects of calcium on one key aspect of lesion development: the migration of macrophages and macrophage/foam cells. Using agarose plate migration assays, the migratory characteristics of macrophages exposed to 1) no lipoprotein, 2) low density lipoprotein (LDL), 3) acetylated low density lipoprotein (acLDL), and ) oxidized low density lipoprotein were examined. The most marked stimulatory effect on macrophage mobility was observed when freshly isolated cells were exposed to acLDL during the migration assay. High levels of exogenous calcium were found to suppress the stimulatory effect of acLDL on migration. As the responses of macrophages exposed to a uniform concentration of agents in the surrounding medium may differ from chemotactic responses to a concentration gradient, the migration of macrophages, with and without preexposure to acLDL or LDL, was studied using microchemotaxis Boyden chambers. Under these conditions, calcium acted as a highly potent chemoattractant, especially to cells that had been preincubated with acLDL. These results suggest how elevated external calcium concentration leads initially to macrophage recruitment, and subsequently to foam cell aggregation and lipid core formation, in association with calcification, in the developing atherosclerotic plaque.

[Effects of a platelet-activating factor antagonist ONO-6240 on antigen induced eosinophil infiltration into the airways]

An in vivo mouse model of allergic bronchial asthma was developed to investigate the effects of a platelet activating factor antagonist ONO-6240 on eosinophil (EOS) recruitment into the mouse airway. In the present study, no EOS could be found in bronchoalveolar lavage fluid (BALF) from normal control mice. However, chronic ovalbumin challenge of sensitized mice induced significant bronchoalveolar eosinophilia (9.68 +/- 0.72 x 10(8)/L). In three groups of mice treated intraperitoneally with different doses of ONO-6240 (0.1, 1.0, 10.0 mg/kg), the medication produced 42.1% (5.60 +/- 0.97 x 10(8)/L, P < 0.01), 58.8% (3.99 +/- 0.84 x 10(8)/L, P < 0.01), and 72.6% (2.65 +/- 0.71 x 10(8)/L, P < 0.01) inhibition, respectively, of the antigen-induced influx of EOS into BALF. It was found that the prevention of EOS infiltration into airway with ONO-6240 was accompanied by decrements of both interleukin (IL)-5 and IL-2 levels. These data indicated that ONO-6240 prevented airway eosinophilia by inhibiting production of IL-5 and IL-2. Our results suggested that ONO-6240 may be of value in treating human asthmatic patients.

[Low dosage of homoharringtonine for prevention of cicatrization after glaucoma filtering surgery]

To prevent the cicatrization of filtering blebs after glaucoma filtering surgery, subconjunctival injections of low dosage homoharringtonine were administered to 22 glaucomatous eyes (20 patients) postoperatively. The percentage of functional filtering blebs was 90.9% and the mean postoperative IOP was 2.04 +/- 0.68 kPa (1 kPa = 7.5 mmHg). In comparison with the control group, the differences were very significant (P < or = 0.01). The results suggest that the toxicity of low dosage of homoharringtonine be very low, it inhibit fibroblast proliferation and play important roles in the formation of the functional filtering blebs and elevation of the success rate of filtration operation.

Quantitative determination of serum iron in human blood by high-performance capillary electrophoresis

A capillary electrophoretic (HPCE) method that can be used to quantitatively determine trace amounts of iron has been developed and applied to determine the iron level in human serum. After precipitation of serum proteins, Fe(III) in the serum is reduced to Fe(II) with hydroxylamine hydrochloride, and a stable Fe(II)-1,10-phenanthroline complex is formed by adding 1,10-phenanthroline to the supernatant containing 2.5 mM ammonium acetate-acetic acid at pH 5.0. The Fe(II)-1,10-phenanthroline complex, [Fe(C12H8N2)3]2+, has a very strong absorbance at 270 nm (with a molar absorptivity of approximately 9.2.10(4)). By measuring the absorbance of [Fe(C12H8N2)3]2+ at 270 nm, the iron level in human serum can be precisely quantified. The interference from copper, a major interference in serum, can be totally eliminated due to the complete separation of [Fe(C12H8N2)3]2+ and the Cu(II)-1,10-phenanthroline complex. In addition, other problems that usually occurred with conventional spectrophotometric methods, such as co-precipitation and occlusion of iron during sample pretreatment, are significantly minimized due to the ability to wash the precipitate and the higher detection sensitivity. With this method, a single drop (10 microliters) of serum would be sufficient to determine the serum iron concentration. The method is reliable, sensitive, rapid and reproducible. Thus it is highly suitable for use in the clinical laboratory.

A role for increased lutropin/choriogonadotropin receptor (LHR) gene transcription in the follitropin-stimulated induction of the LHR in granulosa cells

Follitropin (FSH) has been shown in previous studies to stimulate the induction of the LH/CG receptor (LHR) and LHR mRNA in the granulosa cells of diethylstilbesterol-primed immature rats. The present studies were undertaken to identify the mechanisms underlying the hormone-dependent induction of the LHR in rat granulosa cells. The effect of FSH on LHR mRNA stability was determined by measuring the decay of LHR mRNA after removal of FSH under conditions where transcription was inhibited. Under these conditions, readdition of FSH had little effect on mRNA stability. However, inhibitors of transcription themselves were found to have a marked effect on stabilizing the LHR mRNA, thus potentially masking an effect of FSH. These results suggest that there is a labile destabilizing factor that constitutively degrades LHR mRNA. At present, it cannot be ascertained whether FSH has any effect on this destabilizing factor. Transcriptional activity of the LHR gene was examined using nuclear run-on assays. It was found that 1) in the absence of FSH, LHR-binding activity and mRNA levels were negligible, but the LHR gene was transcriptionally active in granulosa cells of immature rats; 2) incubations of granulosa cells with FSH or 8-bromo-cAMP significantly increased endogenous LHR gene transcription (approximately 10-fold) under conditions where increases in LHR mRNA were observed; 3) the continuous presence of FSH or 8-bromo-cAMP was required to maintain elevated levels of LHR gene transcription and LHR mRNA; and 4) exogenous estradiol alone had no effect on transcription of the LHR gene although it was able to synergistically enhance FSH-induced LHR expression. These experiments suggest that while the effects of estradiol on LHR induction do not appear to be mediated by an increase in LHR gene transcription, the effects of FSH (or cAMP) on LHR induction are clearly mediated, at least in part, by significant increases in the rate of LHR gene transcription.

Scavenging effects of baicalin on free radicals and its protection on erythrocyte membrane from free radical injury

Using electron spin resonance (ESR) spin trapping technique, we found that baicalin (B) could scavenge hydroxyl radicals generated from Fenton reaction. It also could scavenge superoxide radicals generated from the reaction system containing xanthine (X) and xanthine oxidase (XO), as was found by using chemiluminescence (CL) method. Kinetic studies on the competition between baicalin and a spin trap 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) in trapping OH showed that baicalin had a kinetic reactive rate constant of the order of 7.7 x 10(11) M-1 s-1 in its reaction with OH, and the studies on the competition between baicalin and ferricytochrome c (f.c.) in trapping O2- gave a kinetic reactive rate constant of 3.2 x 10(6) M-1 s-1 for baicalin in its reaction with O2-. Furthermore, we have investigated the protective effects of baicalin on erythrocyte membranes from hydroxyl free radical injuries. The results showed that baicalin could reduce hydrogen peroxide-induced hemolysis, protect the conformation of sulfhydryl groups (-SH) on membrane proteins and the membrane fluidity of erythrocytes incubated with hydrogen peroxide. The results indicated that baicalin could protect the membranes of erythrocytes from free radical injuries, and it was even more effective than alpha-tocopherol.

Determination of vitamin A in dried human blood spots by high-performance capillary electrophoresis with laser-excited fluorescence detection

We have developed a high-performance capillary electrophoresis (HPCE) method to analyze the retinol (vitamin A) concentration as retinol-retinol binding protein (holo-RBP) from microvolumes of serum (5-10 microliters) or one to two drops (approximately 20 microliters) of blood collected and air-dried on blood collection filter paper. A 0.64-cm diameter disk was cut from the dried whole blood specimens and the samples were dissolved in a pretreatment buffer and filtered. Filtrate was injected onto the HPCE column for analysis. The separation was carried out in a 60 cm x 50 microns I.D. fused-silica capillary and the running voltage was 20 kV. A He-Cd laser with a wavelength of 325 nm was used for excitation, and the fluorescence of the holo-RBP complex was monitored at 465 nm by a photodiode. A virtual linear relationship was obtained for the retinol concentrations between HPCE and HPLC for 28 serum samples, 19 dried venous blood samples and 9 capillary dried blood spot samples, indicating that valid measures of serum retinol can be obtained from one to two drops of capillary blood collected on filter paper. The absolute detection limit for retinol by HPCE is below 3 micrograms/l. The method is very useful for vitamin A level screening, especially for children and premature new-born babies.

Physical disability in older runners: prevalence, risk factors, and progression with age

BACKGROUND

Concern exists that certain types of exercise, particularly vigorous activity, may increase physical disability among older individuals. We investigated the prevalence of, and risk factors for, physical disability in active older persons (runners), and examined factors influencing the progression of physical disability with age.

METHODS

Physical disability, measured using the Health Assessment Questionnaire Disability Index, was assessed prospectively in 454 runners, age 50 or greater, over five to seven years by annual mailed questionnaires. Baseline sociodemographic, clinical, and life-style characteristics associated with the presence of any disability over the course of the study were determined and contrasted with those in 292 older non-runners who had been similarly followed.

RESULTS

Two hundred twenty-two runners (49%) reported some physical disability during the study. The presence of arthritis symptoms at baseline was the most important risk factor for physical disability; older age, greater body mass index, strenuous work-related physical activity, and the use of more medications were also associated with a greater likelihood of physical disability. Among the non-runners, 224 (77%) reported some physical disability, and the presence of arthritis symptoms was also the most important risk factor for physical disability in this group. Age-related changes in physical disability differed between those with and without arthritis symptoms in both the runner and non-runner groups.

CONCLUSIONS

The presence of arthritis symptoms was an important risk factor for physical disability among both older runners and non-runners, and also identified subgroups of individuals with different progressions of disability with age.

Effects of input pressure on in vitro turtle heart during anoxia and acidosis: a 31P-NMR study

In vitro working hearts of the turtle, Chrysemys picta bellii, paced at 30 beats/min, were studied over a range of input pressures in the following sequence of perfusion conditions: control normoxia, control anoxia, lactacidotic normoxia, and lactacidotic anoxia. Two such series of experiments were performed. In series 1 (n = 12), ventricular pressure (PV) and cardiac output were measured, and power output and dPV/dt were calculated. In series 2 (n = 5), intracellular phosphorus metabolites and intracellular pH (pHi) were also measured using 31P-nuclear magnetic resonance (31P-NMR) spectroscopy. In series 1 all mechanical variables increased with input pressure in generally similar fashion, except during anoxic acidosis, during which mechanical performance was depressed and was increased less or not at all by input pressure. Creatine phosphate (CP) and pHi fell significantly in anoxia and anoxic acidosis, but neither these variables, ATP, CP/ATP, nor, presumably, ADP changed as a function of input pressure with any perfusate despite often large increments in mechanical output. We conclude that anoxia and acidosis act synergistically to depress cardiac function in turtle hearts. Also, the insensitivity of NMR variables to changes in input pressure and cardiodynamics suggests that changes in these variables are unimportant for controlling energy turnover in this preparation.

[Inhibitory effect of anti-motoneuron serum on the neurite outgrowth of spinal cord explants (in vitro) and the cross-reactivity of serum to human and rat motoneurons]

The effects of rabbit anti-swine motoneuron serum (RAS), normal rabbit serum (NRS), skeletal muscle extracts (MET, 50 and 100 micrograms/ml) and brain extracts (BET, 50 and 100 micrograms/ml) on neurite outgrowth of neonatal rat spinal cord explants (in vitro) were studied after 5 days of treatment. In comparison with NRS (explants possessing neurite outgrowth accounted for 36.7%, n = 30), the neurite outgrowth of spinal cord explants was significantly accelerated by MET (96.7% of explants had neurite outgrowth), but inhibited by RAS (only 13.3% of the explants had neurite outgrowth). The cross-reactivity of RAS to the spinal motoneuron of swine, humans and rats were also demonstrated by immunocytochemical techniques.

A new parallel binary image shrinking algorithm

A new parallel binary image shrinking algorithm that can be considered as an improvement of Levialdi's (1972) parallel shrinking algorithm and can be used in many image labeling algorithms as a basic operation in order to reduce the storage requirements for local memory and speed up the labeling process is presented. This new parallel shrinking algorithm shrinks an nxn binary image to an image with no black pixels in O(n) parallel steps with a multiplicative constant of 1.5, preserving the 8-connectivity in the shrinking process.

Spatial distribution of 3-hydroxy-3-methylglutaryl coenzyme A reductase messenger RNA in the ocular lens: relationship to cholesterologenesis

This study probes the regulation of cholesterol biosynthesis in the ocular lens by estimating the concentration and distribution of the messenger RNA for the rate-controlling enzyme for sterol synthesis, 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR). Because the lens is dependent on biosynthesis for cholesterol, HMGR activity is crucial for the life-long growth of this organ. Young rat lenses were serially divided into several fractions by dissolution in an SDS-containing buffer and each fraction was equated to a percent of the lens radius based upon its protein content. HMGR enzyme activity and cholesterol synthesis has been shown to disappear from the lens cortex over a narrow arc of radius due to loss of enzyme protein. Using a published competitive reverse transcriptase-polymerase chain reaction method for amplifying HMGR mRNA (Powell, E. E., and P. A. Kroon. 1992. J. Lipid Res. 33: 609-614), an average of about 46,000 copies of this mRNA was estimated per lens at all rat ages examined (5-day-old to adult). However, copies/microgram total RNA decreased with aging. The distribution of HMGR mRNA across 95-60% of the lens radius was essentially uniform at 2000-3000 copies/mm3 tissue. But the very superficial cortex contained 5- to 7-times this concentration and accounted for about 35% of the total copies/lens. We estimated that cells in this region each contained 1 to 2 copies of message, a value similar to the estimated copy number of HMGR message in human lymphocytes (Powell and Kroon, ibid). This suggests that the translational efficiency and stability of lens HMGR mRNA must be very high.(ABSTRACT TRUNCATED AT 250 WORDS)

Impairment of GABAA receptor function by N-methyl-D-aspartate-mediated calcium influx in isolated CA1 pyramidal cells

Mechanisms of regulation of GABAA receptor function by intracellular calcium ([Ca2+]i) were examined in cell somata and apical dendrites of pyramidal cells, acutely dissociated from the CA1 hippocampal subfield of adult guinea-pigs. GABAA receptor-mediated currents were measured by whole-cell clamp recordings. N-methyl-D-aspartate receptor-mediated currents were used as conditioning source of calcium influx. Peak amplitudes of somatic GABAA whole-cell currents were reduced to about 15% of control values when net inward charge accumulation by N-methyl-D-aspartate currents reached 1.85 nC. A similar decline of GABAA currents was observed in dendritic recordings. The N-methyl-D-aspartate-mediated reduction of somatic and dendritic GABAA currents was accompanied by a well correlated decrease in peak and chord conductances. Pharmacological blockade of N-methyl-D-aspartate currents by 2-amino-5-phosphonopentanoic acid prevented the N-methyl-D-aspartate-mediated suppression of GABAA responses. The N-methyl-D-aspartate effect was mediated by the calcium component of N-methyl-D-aspartate receptor-mediated currents as demonstrated by a lack of effect in the absence of extracellular calcium and faster N-methyl-D-aspartate-mediated suppression of GABAA responses in lower intracellular 1,2-bis(2-aminophenoxy)ethane-N,N,N',N"-tetra-acetate. N-methyl-D-aspartate-mediated suppression of GABAA currents was significantly less expressed when intracellular ATP was replaced by its analog adenosine 5'-O-(3-thiotriphosphate) and when the specific phosphatase 2B inhibitor cypermethrin was added intracellularly. The reduction of GABAA responses persisted after cessation of N-methyl-D-aspartate-mediated calcium influx, indicating a long-term action of N-methyl-D-aspartate on GABAA responses. Voltage-activated calcium currents did not affect GABAA responses under the experimental conditions applied. In conclusion, the data presented show that calcium influxes through N-methyl-D-aspartate receptor channels result in long-term suppression of GABAA receptor function in CA1 pyramidal cells. Intracellular mechanisms of N-methyl-D-aspartate-mediated reduction of GABAA conductances involve activation of phosphatase 2B and consecutive dephosphorylation of the GABAA receptor or a closely associated GABAA receptor-regulating enzyme. Possible mechanisms of such a distinct N-methyl-D-aspartate-dependent calcium signalling pathway in the dephosphorylation-dependent suppression or GABAA receptor function are discussed.

Interactions of both melittin and its site-specific mutants with bacteriorhodopsin of Halobacterium halobium: sites of electrostatic interaction on melittin

Melittin and its site-specific mutants differentially delay the slow-decaying component of the photocycle intermediate M412 of bacteriorhodopsin in the purple membrane and the acetylated purple membrane whose several lysine residues are modified. This effect is attributed to the interaction of the total positive charges of melittin or its mutants with the total negative charges of bacteriorhodopsin. The effects of melittin and its mutants on the Triton X-100-solubilized bacteriorhodopsin monomers are somewhat complicated but are associated with their charges. These results show that there is electrostatic interaction between bacteriorhodopsin and melittin and that both N- and C-termini of melittin function as sites of the interaction, with Arg 22 and Arg 24 making a prominent contribution to the effective surface charge of melittin. Melittin, at certain concentrations, partially restores the decreased photoactivity of the bacteriorhodopsin monomers trapped in the Triton-lipid-protein mixed micelles, which suggests that melittin may compete with Triton X-100 for the binding sites on the bacteriorhodopsin monomers. Other kinds of interactions between bacteriorhodopsin and melittin are also indicated. The possible states of melittin in membranes are discussed.

[Molecular cytogenetic study of Turner's syndrome with the 45, X/46,X,r(?) karyotype]

Two small marker chromosomes were identified as X-derived ring chromosomes by using the high-resolution banding technique and in situ hybridization with a radioactively labelled human X-chromosome-specific satellite DNA probe. This procedure clearly determined the origin of the marker chromosome, which had been impossible using conventional cytogenetic techniques. The clinical significance of this work is briefly discussed.

Characterization of a mitogen-response unit in the mouse lactoferrin gene promoter

Lactoferrin is present in a variety of tissues and biological fluids; however, the amount differs significantly due to differential expressions. We have previously demonstrated that the mouse lactoferrin gene is regulated by estrogen through an estrogen-response DNA element located at -349, upstream from the transcription start site (+1). In this report, we characterized by deletion and mutation analyses a cluster of mitogen-response elements located between -80 and -40 of the mouse lactoferrin promoter. We demonstrated that the chimeric chloramphenicol acetyltransferase reporter constructs (the -103 to +1 sequence of the mouse lactoferrin gene) containing the mitogen-response unit of the lactoferrin gene were stimulated by cAMP, forskolin, 12-O-tetradecanoylphorbol-13-acetate, and epidermal growth factor/recombinant transforming growth factor-alpha (EGF/TGF-alpha) in a time- and dose-dependent manner. The sequence at position -52 to -40 (mLF-CRE) of the gene conferred transcriptional activation in the presence of forskolin, cyclic AMP, and 12-O-tetradecanoylphorbol-13-acetate in transiently transfected human endometrium carcinoma RL95-2 cells, whereas the region at -80 to -60 responded to EGF/TGF-alpha stimulation. Overexpression of the catalytic unit of protein kinase C or protein kinase A in the RL95-2 cells elevated the chloramphenicol acetyl-transferase activity of the reporter construct 5-6-fold. The mobility shift assay suggested that AP1 and CREB or related proteins participated in complex formation with the mLF-CRE, whereas different proteins bound to the EGF/TGF-alpha-response element.

Regional distribution of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and protein mass in the ocular lens

We have attempted to map the regional distribution of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) enzyme activity and protein mass along the radial axis of the ocular lens. Because lens plasma membrane is extremely rich in cholesterol and the lens must synthesize this cholesterol, the activity of HMGR could be a key factor controlling lens membrane formation. Lenses of young rats were divided into discrete fractions by gradual dissolution in a tergitol-containing buffer; each fraction was then equated to a specific arc of the radius based upon its protein content. Aliquots of each fraction were assayed for HMGR enzyme activity and protein mass. Relative protein mass was quantitatively estimated by Western blotting using a monoclonal antibody to HMGR with immunoreactivity detected by enhanced chemiluminescence. Lens HMGR possessed a molecular mass of about 97 kDa and localized in the cell's insoluble fraction. Peak levels of both HMGR enzyme activity and protein mass were found in the outer 5% of the lens radius; levels of both decreased precipitously from there to the outer 10% radius mark. This distribution paralleled synthesis of the membrane's cholesterol, phospholipid, and intrinsic protein. We conclude that the abrupt cessation of plasma membrane synthesis in the ocular lens could involve loss of HMGR activity over a narrow arc of the lens radius, and that this activity loss is due to disappearance of enzyme protein.

Structure-refinement program for disordered carbons

An automated structure-refinement program has been developed for X-ray powder diffraction data collected on disordered carbons. The program minimizes the difference between the observed and calculated diffraction profiles in a least-squares sense by optimizing model parameters analogously to the popular Rietveld refinement method. Unlike the Rietveld method, which is designed for crystalline materials, this program allows the quantification of the finite size, strain and disorder present in disordered carbon fibers and cokes. For example, the structural model used includes the probability of a random translation parallel to adjacent carbon layers as a refinable parameter describing turbostratic disorder. Other parameters are used to describe finite size, fluctuations in the spacing between adjacent layers, average lattice constants, background and other important quantities. The structural model, combined with the refinement program, acceptably describes the diffraction patterns from disordered carbons such as pitch heated near 823 K, cokes, fibers, heat-treated cokes and synthetic graphite.

Antioxidant properties of fractions and polyphenol constituents from green, oolong and black teas

Green, oolong and black teas were extracted with water, and then the water extracts were extracted separately with three types of solvent, chloroform, ethyl acetate and butanol, to obtain eight fractions. Major flavanol was extracted by EtOAc, while most of the alkaloid was in the chloroform fraction. Thearubigin was greatest in the butanol fraction, and most of the amino acid remained in the water fraction. All fractions were systematically analyzed by UV spectrophotometer and reverse phase HPLC for those important components existing in green tea, oolong tea, and black tea. The pure compounds of (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC), (-)-epigallocatechin gallate (EGCG), free theaflavin, theaflavin monogallate-A, theaflavin monogallate-B, and theaflavin digallate were separated by LH-20 chromatography and reverse phase HPLC. All fractions and pure compounds were assayed for antioxidant activity and lipoxygenase inhibition activity. Flavanol showed very strong antioxidant activity and lipoxygenase inhibition.

The risk of osteoarthritis with running and aging: a 5-year longitudinal study

Our purpose was to determine the 5-year longitudinal effects of running and aging on the development of radiographic and clinical osteoarthritis (OA) of the knees, hands and lumbar spine. Thirty-five running subjects and 38 controls, with a mean age of 63 years, were matched for age (+/- 2 years), years of education, and occupation; 33 matched pairs were constructed. All subjects underwent rheumatologic examination, completed questionnaires, and had radiographs taken of the hands, lateral lumbar spine, and knees in 1984 and in 1989. Five year radiographic results for both the runner and control groups showed OA progression for the knees, hands, and lumbar spine. In 1989, 10 (13%) of the 73 subjects fit American College of Rheumatology (ACR) criteria for clinical OA of the hand, and 9 subjects (12%) fit ACR criteria for OA of the knee. In summary, running did not accelerate the development of radiographic or clinical OA of the knees, but with aging, 13% of all subjects developed OA of the hands and 12% of all subjects developed OA of the knees.

Molecular mimicry of hepatitis B surface antigen by an anti-idiotype-derived synthetic peptide

Monoclonal antibody 2F10 is an "internal-image" anti-idiotype (anti-id) antibody capable of mimicking the group-specific "a" determinant of human hepatitis B surface antigen (HBsAg). By mRNA sequencing and computer-assisted molecular modeling of monoclonal antibody 2F10, we identified a 15-amino acid region of the heavy-chain hypervariable region that has partial residue homology with sequences of the "a" determinant epitopes of HBsAg. We have established that a linear 15-mer peptide from a contiguous region on the anti-id antibody can (i) generate anti-HBsAg-specific antibodies when injected into mice, (ii) prime murine lymph node cells for in vitro HBsAg-specific T-cell proliferative responses, and (iii) stimulate in vitro human CD4+ T cells that were primed in vivo to HBsAg by natural infection with hepatitis B virus or vaccination with a commercially available HBsAg vaccine. Significantly, this peptide could also stimulate CD4+ T cells of human hepatitis B virus carriers. We conclude that a 15-mer peptide derived from the anti-id sequence can duplicate the B- and T-cell stimulatory activity of the intact anti-id antibody and the antigen that is mimicked, HBsAg.

The effect of platelet activating factor on different phases of murine in vitro fertilization

PURPOSE

Our purpose was to examine the effect of platelet activating factor (PAF) in different phases of mouse in vitro fertilization and optimal parameters that would enhance the fertilization rate.

DESIGN AND SETTINGS

Various PAF concentrations (10(-7) to 10(-5) M) were selected to investigate its effect on three phases of mouse in vitro fertilization (i.e., sperm capacitation, sperm/oocyte coincubation, and preimplantation embryo growth) in three experimental groups: (I) with PAF treatment in the first phase, (II) with PAF treatment adopted in the first and second phases, and (III) with PAF treatment implemented in all three phases.

RESULTS

The improvement of the fertilization rate in PAF treatment groups over the control group ranges from 6.5 to 19.0% (P < 0.05-P < 0.001). The highest enhancement of fertilization rate was achieved under the condition of PAF treatment (10(-6) M) through sperm capacitation and sperm/oocyte coincubation phases.

CONCLUSION

The PAF concentration of 10(-6) M in sperm capacitation and sperm/oocyte coincubation yielded the greatest improvement in fertilization. However, continuing PAF treatment after sperm/oocyte coincubation had no beneficial effect on fertilization and preimplantation development.

Antioxidative effect of polyphenol extract prepared from various Chinese teas

METHODS. Twelve different types of Chinese teas, including green, semifermented, and black tea, were studied for their antioxidant activities and active components. Compositions of (-)-epicatechin, (-)-epigallocatechin, (-)-epicatechin gallate, (-)-epigallocatechin gallate, and gallic acid were identified by fast atom bombardment-mass spectrometry and high-performance liquid chromatography-mass spectrometry and quantified by high-performance liquid chromatography. Antioxidant activities in lard were measured by the Rancimat method. RESULTS. The results showed that both yields of polyphenol extract and antioxidant activities varied with different tea processing methods. It was found that (-)-epigallocatechin gallate, (-)-epigallocatechin, and (-)-epicatechin gallate inhibited soybean lipoxygenase at the IC50 values ranging from 10 to 20 microM.