Becoming gold-plated: Chinese nurses studying abroad

The purpose of this interpretive study is to describe the experience of Chinese nurses studying abroad. Twenty-three nurses living in Taiwan, who had studied in the United States for university degrees, were interviewed in 1990. A central process was "Becoming gold-plated." The first major theme was "Enormous pressure and sacrifice," with the subthemes of "Self-doubt," "Language difficulties," "Isolation and loneliness," and "Separation and guilt." The second major theme was "Transformed self," with subthemes of "High aspiration" and "New perspective on life." In spite of the hardships of study abroad, Chinese nurses felt pride in their accomplishment and self-respect for the knowledge and sophistication they gained.

Age-related difference in the response of plasma erythropoietin to hemorrhage in ovariectomized rats

The effect of aging on plasma erythropoietin (EPO) levels after acute hemorrhage was investigated in ovariectomized (Ovx) rats. Old (22 months), middle (mid)-aged (14 months) and adult (5-6 months) Ovx rats were studied. Rats were anesthetized with ether and bled by heart puncture (5 ml/kg). They were bled again after 1 h. The hematocrit and concentration of plasma EPO were determined for both bleedings. The prehemorrhage level of hematocrit was not altered by aging. The hematocrit level after hemorrhage was greater in old than in mid-aged (p < 0.05) and adult (p < 0.01) rats. The basal level of plasma EPO in old rats was higher than that in the adult rats (p < 0.05), but not in the mid-aged rats. The concentration of plasma EPO in response to hemorrhage was increased in all rats (p < 0.01). The hemorrhage-induced increase in plasma EPO was significantly greater in adult rats than in both mid-aged and old rats (p < 0.05). Our findings indicate that the basal level of plasma EPO is increased, but the hemorrhage-induced EPO secretion is diminished in ovariectomized rats during aging. These data then suggest that the tolerance to hemorrhage and the secretory function of EPO are changed by age.

Genetic control of the murine humoral response to distinct epitopes of hepatitis C virus core protein

Recombinant hepatitis C virus (HCV) core protein from aa1-164, designated cp1-10, was used to immunize mice. Antibodies to cp1-10 were produced in all seven strains of congenic mice; none of the strains could be considered low responders relative to the others. The mouse response against individual epitopes of HCV core protein varied from one strain to another: B10.RIII (H-2r) recognized all three peptides aa13-30, aa77-90, aa129-145; B10.D2 (H-2d), B10 (H-2b) and C3H.SW (H-2b) responded to aa13-30, aa77-90; B10.M (H-2f), B10.BR (H-2k) and C3H/Hej (H-2k) reacted with aa13-30 only. Competitive inhibition of binding demonstrated that antibody to the peptide was inhibited by cp1-10 protein and the corresponding peptide only. Recombinant HCV core protein is highly immunogenic and can elicit good antibody response in mice. The aa13-30 is a major epitope of HCV core protein in mice. The humoral response to the distinct epitopes was regulated by the H-2 genes. Further analysis indicated that the I-a locus of H-2 genes determined the antibody response to aa13-30 and 77-90. These results suggest that the variation of antibody responses to HCV in humans may partially contribute to different outcomes of HCV infection.

Effect of proprioceptive neuromuscular facilitation on the gait of patients with hemiplegia of long and short duration

BACKGROUND AND PURPOSE

The immediate and cumulative effects of proprioceptive neuromuscular facilitation (PNF) applied to the pelvic region on the gait of patients with hemiplegia of short and long duration were studied.

SUBJECTS

The subjects were 20 patients with hemiplegia of short duration (mean = 4.4 months, SD = 0.8, range = 2.8-5.6; n = 10) or long duration (mean = 15.4 months, SD = 1.7, range = 12.7-18.5; n = 10).

METHODS

Each subject received a total of 12 sessions of PNF (three times per week), with each treatment lasting for 30 minutes.

RESULTS

In subjects with hemiplegia of short duration, gait speed and cadence improved immediately after 1 session of PNF, and this improvement was further enhanced after 12 treatments. By contrast, subjects with hemiplegia of short duration.

CONCLUSION AND DISCUSSION

These data suggest that (1) in both groups of patients with hemiplegia, the cumulative effects of PNF is more beneficial than the immediate effects, and (2) patients with hemiplegia of short duration respond to training sooner than do patients with hemiplegia of long duration, although the cumulative effects are similar for both groups.

[Factors affecting young children's mental development and their significance in intervention]

Factors affecting their developmental quotients (DQ) in 48 normal young children, who were involved in regular development assessments at child health care outpatient visits and whose parents received child-rearing guidance at Chaoyangmen Subdistrict of Dongcheng District, Beijing, and 43 controls aged 36 months were analyzed. Factors, such as their parents' receiving child-rearing guidance, paternal education, maternal education, paternal occupation, type of nursery schools, home environment quality score (HEQS) at 24 and 36 months of age, and mothers' knowledge of child-rearing were associated with children's DQ at their age of 36 months, with statistical significance at a level of 0.05 in univariate analysis. With multiple regression analysis, HEQS at the age of 36 months, family size at the age of 24 months, paternal education, children's sex, and mothers' age had influences on DQ at age of 36 months with statistical significance, and the degree of correlation of HEQS with DQ at 36 months was much higher than that of other factors, and it suggested that HEQS was an important link in child developmental intervention.

Effect of pertussis toxin on the response of rat medial prefrontal cortex cells to the iontophoresis of serotonin receptor agonists

In this study, we examined the response of spontaneously active as well as quiescent cells (L-glutamate-activated) in the rat medial prefrontal cortex (mPFc) to the iontophoresis of 2-methylserotonin (2-Me-5-HT, 5-HT3 receptor agonist), (+/-)-2,5-dimethoxy-(4-iodo-phenyl)-2-aminopropane (DOI, 5-HT2A,2C receptor agonist), 8-hydroxy-N,N-di-propylamino tetralin (8-OH-DPAT, 5-HT1A receptor agonist) and gamma-aminobutyric acid (GABA, a non-selective GABA receptor agonist) after the intracerebral administration of pertussis toxin, an inactivator of the Gi/o protein. This was accomplished using the techniques of extracellular single cell recording and iontophoresis. The administration of pertussis toxin (0.5 microgram, 24 hours before the experiment) into the mPFc did not alter the response of mPFc cells to the iontophoresis of DOI, 2-Me-5HT or GABA compared to saline treated controls. However, the response of mPFc cells to the iontophoresis of 8-OH-DPAT was significantly attenuated in the animals pretreated with pertussis toxin compared to controls. These results suggest that the 5-HT1A but not 5-HT2A,2C or 5-HT3 receptor is coupled to the Gi/o protein.

The role of 5-HT3-like receptors in the action of clozapine

The serotonin3 (5-HT3)-like receptors play an important role in modulating the inhibitory action of dopamine in the mesocorticolimbic regions. The atypical antipsychotic drugs clozapine and RMI 81,582, but not other antipsychotic drugs, blocked the suppressant action produced by the 5-HT3 receptor agonist 2-methyl-5-HT on the firing rate of medial prefrontal cortical cells. Since the localization of 5-HT3 receptors overlaps with the mesocorticolimbic but not the nigrostriatal dopamine system, it is hypothesized that the preferential action of clozapine on the mesocorticolimbic dopamine system is the result of the drug's interaction with the 5-HT3-like receptors. Furthermore, the antagonizing effect of clozapine to 5-HT3-like receptors may contribute to its increased antipsychotic efficacy.

The 5-HT3 receptor agonist 2-methyl-5-HT reduces postsynaptic potentials in rat CA1 pyramidal neurons of the hippocampus in vitro

The effects of the serotonin (5-HT)3 receptor agonist, 2-methyl-5-hydroxytryptamine (2-methyl-5-HT), were studied in CA1 pyramidal cells of the rat hippocampus in vitro using the whole cell gigaseal technique. 2-Methyl-5-HT (10 and 50 microM) did not change significantly the electrophysiologic properties of the cells but reversibly reduced excitatory and inhibitory postsynaptic potentials evoked by stimulation of the Schaffer collaterals. The onset and termination of this effect was in the order of minutes and no desensitization was observed. The selective 5-HT3 receptor antagonist, granisetron, when applied as a pretreatment completely prevented but did not reverse this action when given after administration of 2-methyl-5-HT while the non-specific 5-HT1,2 receptor antagonist, metergoline, was ineffective. These results suggest that the activation of 5-HT3 receptors reduces the efficacy of glutamatergic synaptic transmission in this area.

Ion chromatography with suppressed conductivity detection: recoveries of 14C-labeled metabolites

Suppressed conductivity detection, developed for use with ion chromatography, might be useful to assay specific activities of organic acids after metabolic labeling. Because the suppressor reduces background conductivity by acid-base neutralization and removal of ions from the eluent, it could influence recoveries and apparent retention times of labeled compounds. Elution times of 14C-labeled glucose and neutral amino acids, compounds not detected by conductivity, from the analytical column were found to be similar to those of lactate and acetate. When the suppressor was connected to the HPLC system in the recycle mode, the apparent elution times of amino acids increased and various organic acid fractions would be contaminated. When the suppressor was used in the external water mode, the labeled neutral amino acids and portions of acidic amino acids were recovered in the waste fraction; this indicated that recoveries of total 14C in the analyte fraction would be incomplete if the loss were not taken into account. Thus, the procedure to insert the suppressor into the system influences the apparent retention times and the recoveries of labeled amino acids in the analyte fraction; labeled metabolites not detected by conductivity can cause serious errors in specific activities of organic acids and should be removed from the sample prior to analysis.

Electrophysiological evidence for a functional interaction between 5-HT1A and 5-HT2A receptors in the rat medial prefrontal cortex: an iontophoretic study

In this study, we examined the interaction of 5-HT1A and 5-HT2A receptors in the rat medial prefrontal cortex (mPFc) using the techniques of extracellular single unit recording and microiontophoresis. The iontophoresis of the selective 5-HT1A receptor agonist (+-)-8-hydroxy-2-(di-n-propylamino) tetralin (8-OHDPAT) produced a current-dependent suppression (2.5-20 nA) of the basal firing rate of spontaneously active mPFc cells. The iontophoretic (5-10 nA) and systemic administration (0.1-0.5 mg/kg, i.v.) of the 5-HT2A/5-HT2C receptor antagonist ritanserin and the selective 5-HT2A receptor antagonist MDL 28727 significantly potentiated and prolonged 8-OHDPAT's suppressant action. In addition, the systemic administration of another selective 5-HT2A antagonist MDL 100907, but not its less active enantiomer MDL 100009, also potentiated and prolonged 8-OHDPAT's action. The potentiating effect of the 5-HT2A receptor antagonists on the action of 8-OHDPAT is specific in that neither the iontophoresis of ritanserin nor MDL 28727 altered the suppressant action produced by the iontophoresis of the 5-HT3 receptor agonist 2-methylserotonin onto mPFc cells. Moreover, the suppressant action of 8-OHDPAT was not altered by the systemic administration of the selective 5-HT3 receptor antagonist granisetron (0.1-0.5 mg/kg, i.v.). On the other hand, the iontophoresis of a low current (0.5 nA) of the 5-HT2A,2C receptor agonist (+-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) potentiated the excitation induced by the iontophoresis of l-glutamate on quiescent mPFc cells.(ABSTRACT TRUNCATED AT 250 WORDS)

The behavioral effects of the stereoisomers of 4-methylaminorex, a psychostimulant, in the rat

In this study, we examined the effect of the isomers of the psychostimulant 2-amino-4-methyl-5-phenyl-delta 2-oxazoline (4-methylaminorex or 4-MAX) on behavior in rats. The s.c. administration of the stereoisomers of 4-MAX, trans-4S,5S, cis-4R,5S, cis-4S,5R and trans-4R,5R (0.3-3 mg/kg), produced a dose-dependent increase in locomotor activity. However, at a dose of 10 mg/kg, the isomers of 4-MAX produced an initial increase in locomotor activity followed by the appearance of stereotyped behaviors (continuous sniffing, chewing, head bobbing, etc.) then a subsequent phase of rebound-enhanced locomotor activity all over a time course of 4 hr. The rank order of potency for the stereoisomers of 4-MAX was: 4S,5S > 4R,5S =4S,5R < 4R,5R. To determine what neurotransmitter systems may mediate the action of 4-MAX, the ability of various receptor antagonists to block or attenuate the effect of trans-4S,5S-4-MAX (3 mg/kg s.c.) on locomotor activity was examined. The selective dopamine (DA) D1 antagonist (-)-trans-6,7,7a,8,9,13b-hexahydro-3-chloro-2-hydroxy-N-methyl-5H- benzo- [d]naph-thio[2,1b]azepine (SCH 39166) and the D2 receptor antagonist (-)-eticlopride significantly, attenuated the behavioral action of trans-4S,5S-4-MAX, whereas antagonists to serotonergic and adrenergic receptors were ineffective. These results suggest that the ability of 4S,5S-4-MAX to induce locomotor hyperactivity and stereotypical behaviors and to increase rearing durations is primarily mediated by DA receptors. To determine whether the action of 4-MAX is dependent upon 5-hydroxytryptamine or DA concentrations in nerve terminals, rats were pretreated with either reserpine, alpha-methyl-p-tyrosine or d,l-p-chlorophenylalanine. Both reserpine and alpha-methyl-p-tyrosine pretreatment markedly attenuated the locomotor activity produced by trans-4S,5S-4-MAX. Moreover, L-dopa partially reversed the inhibitory action of alpha-methyl-p-tyrosine on 4S,5S-4-MAX-induced behavioral activation. In contrast, the administration of d,l-p-chlorophenylalanine did not alter the behavioral responses produced by trans-4S,5S-4-MAX. Taken together, our results suggest that 4-MAX may increase several locomotor behaviors by inducing neuronal DA release, which subsequently interacts with dopaminergic receptors.

The induction of serotonin3-like receptor supersensitivity and dopamine receptor subsensitivity in the rat medial prefrontal cortex after the intraventricular administration of the neurotoxin 5,7-dihydroxytryptamine: a microiontophoretic study

This study examines the effect of intraventricular administration of the neurotoxin 5,7-dihydroxytryptamine on serotonin1A, serotonin2 and serotonin3 receptors in the rat medial prefrontal cortex using in vivo extracellular single cell recording and iontophoresis. Iontophoresis of the serotonin1A, serotonin1C,2 and serotonin3 receptor agonists (+-)-8-hydroxy-(di-n-propyl)aminotetralin, (+-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane and 2-methylserotonin, respectively, produces a current-dependent (5-80 nA) suppression of the basal firing rate of medial prefrontal cortical cells in sham- and 5,7-dihydroxytryptamine-lesioned rats. The suppression produced by 2-methylserotonin and serotonin was significantly greater in 5,7-dihydroxytryptamine-lesioned rats than in control rats. No significant difference in the spontaneous activity of medial prefrontal cortex cells was observed between experimental and control rats after iontophoresis of (+-)-8-hydroxy-(di-n-propyl)aminotetralin or (+-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane. There was no significant difference between the groups regarding the response of medial prefrontal cortex cells to the iontophoresis of GABA, whereas the response of medial prefrontal cortex cells to the iontophoresis of dopamine was significantly attenuated in animals pretreated with 5,7-dihydroxytryptamine compared to controls. Our results indicate that 5,7-dihydroxytryptamine-induced denervation selectively enhances the sensitivity of serotonin3-like receptors in the medial prefrontal cortex, which could, at least partially, account for the serotonin denervation supersensitivity. Moreover, the finding that the response of medial prefrontal cortical cells to the iontophoresis of dopamine is attenuated in 5,7-dihydroxytryptamine pretreated rats is consistent with the view that the inhibitory action of dopamine in the medial prefrontal cortex is dependent upon serotonin tone.

Serotonin3 receptor agonists attenuate glutamate-induced firing in rat hippocampal CA1 pyramidal cells

The techniques of extracellular single cell recording and microiontophoresis were used to study the effect of 5-HT3 receptor agonists on glutamate-activated firing of CA1 hippocampal pyramidal cells. Iontophoretic application of 5-HT3 receptor agonists 2-methyl-5-HT and SR 57227A produced a current (dose)-dependent suppression of the firing of CA1 pyramidal cells; SR 57227A was more effective than 2-methyl-5-HT. The suppressant action of 2-methyl-5-HT and SR 57227A had a slow onset and showed little or no desensitization. This effect was markedly attenuated or completely blocked by the 5-HT3 receptor antagonist BRL 46470A but not by the nonspecific 5-HT1 and 5-HT2 receptor antagonist metergoline or by the 5-HT1A antagonist WAY 100478. Intravenous administration of SR 57227A was effective in reducing the firing rate of CA1 pyramidal cells and this effect was prevented by BRL 46470A administered either i.v. or iontophoretically. Iontophoresis of 2-methyl-5-HT also diminished CA1 postsynaptic field potentials evoked by electrical stimulation of the Schaffer collaterals. Again, BRL 46470A but not metergoline prevented the suppressant action of 2-methyl-5-HT. Taken together, our results indicate that activation of 5-HT3-like receptors in the hippocampal CA1 region effectively reduces the efficacy of glutamatergic neurotransmission.

The effect of 5-HT3 receptor antagonists on the morphine-induced excitation of A10 dopamine cells: electrophysiological studies

In extracellular recordings from chloral hydrate anesthetized rats the 5-HT3 antagonist, BRL 46470A, failed to prevent or reverse the increase in dopamine cell firing rate produced by systemic or iontophoretically applied morphine. A second 5-HT3 antagonist, tropesitron, was similarly found to be ineffective in antagonizing the effects of systemic morphine. These results suggest that previous microdialysis reports that 5-HT3 antagonists can prevent the increase in extracellular dopamine levels in the nucleus accumbens produced by morphine are not due to an action of these compounds in suppressing the excitatory effects of morphine on A10 dopamine cell firing rate.

Index assignment for progressive transmission of full-search vector quantization

The authors study codeword index assignment to allow for progressive image transmission of fixed rate full-search vector quantization (VQ). They develop three new methods of assigning indices to a vector quantization codebook and formulate these assignments as labels of nodes of a full-search progressive transmission tree. The tree is used to design intermediate codewords for the decoder so that full-search VQ has a successive approximation character. The binary representation for the path through the tree represents the progressive transmission code. The methods of designing the tree that they apply are the generalized Lloyd algorithm, minimum cost perfect matching from optimization theory, and a method of principal component partitioning. Their empirical results show that the final method gives intermediate signal-to-noise ratios (SNRs) that are close to those obtained with tree-structured vector quantization, yet they have higher final SNRs.

Prevalence of sorbitol in multiple-dose activated charcoal regimens in emergency departments

STUDY OBJECTIVES

To determine the availability and use of premixed activated charcoal in sorbitol preparations during multiple-dose activated charcoal therapy in the emergency department.

DESIGN AND SETTING

A prospective telephone survey of all 911 receiving hospitals within the catchment area of one poison center.

TYPE OF PARTICIPANTS

Hospital pharmacy supervisors and ED charge nurses.

INTERVENTION

Hospital pharmacy supervisors were surveyed about the available preparations of activated charcoal on their hospital's formulary, and ED charge nurses in these same hospitals were surveyed about the prevalence of sorbitol use in multiple-dose activated charcoal regimens.

MEASUREMENTS AND MAIN RESULTS

Eleven hospitals (16%) stocked only activated charcoal in sorbitol preparations. Twenty-one hospitals (31%) had both activated charcoal in sorbitol preparations and activated charcoal without sorbitol preparations, and 35 hospitals (52%) had only activated charcoal without sorbitol preparations. Repeat dosing of sorbitol during multiple-dose activated charcoal therapy occurred in 33 of 67 (49%) of the EDs surveyed.

CONCLUSION

Sorbitol dosing is often repeated with activated charcoal during multiple-dose activated charcoal therapy in the ED because of the ready availability (and sometimes exclusive availability) of premixed activated charcoal in sorbitol preparations.

Determination of albendazole-2-aminosulfone in bovine milk using high-performance liquid chromatography with fluorometric detection

An analytical method for the determination of albendazole (ABZ) residues in bovine milk was developed using one of its major metabolites, albendazole-2-aminosulfone (ABZ2NH2) as the marker. The method involved acid hydrolysis of milk followed by liquid-liquid extraction and solid-liquid phase clean-up of the extract. A reversed-phase HPLC with fluorometric detection was used to quantitate the marker residue. The method exhibited a high degree of precision and good accuracy as demonstrated by a relative standard deviation (R.S.D.) < 5% for the replicate analyses and 91.8 to 104.1% recovery of the fortification level (25-200 ng/ml), respectively. The ratio of the concentrations of the marker and total residues in milk over a 36-120 h withdrawal period was found to be steady at 43.1 indicating a definite relationship between the marker and the total residues of ABZ. The analytical method was used successfully to determine total residues in milk of cattle treated with ABZ.

Mycoplasma penetrans infection in male homosexuals with AIDS: high seroprevalence and association with Kaposi's sarcoma

Antibodies to Mycoplasma penetrans were found at an unusually high frequency in male homosexuals with AIDS (55 of 149; 37%) and in human immunodeficiency virus (HIV)-infected asymptomatic homosexuals (13 of 49; 26.5%) but not in intravenous drug users (3 of 308; 1%) and hemophiliacs (1 of 165; 0.6%) with or without HIV-1 infection. Thus, both M. penetrans and Kaposi's sarcoma (KS) occur primarily in male homosexuals and rarely in other groups of patients at high risk of AIDS. Among 414 HIV-1-infected patients, statistical analysis revealed those with M. penetrans antibody were 11.7 times more likely to develop KS. Furthermore, among 198 HIV-infected homosexuals (149 with AIDS and 49 without AIDS), those with KS had M. penetrans-specific antibody at a significantly higher frequency (28 of 47; 59.6%) than did those without KS (27 of 102 with AIDS [26.5%] as well as 13 of 49 without AIDS [26.5%]; odds ratio = 4.1, P < .001). M. penetrans is apparently transmitted sexually through homosexual activity and is epidemiologically linked to formation of KS in homosexual men with AIDS. Parallel tests with M. genitalium revealed no similar link to KS in the same study sample.

Fatal systemic infections of nonhuman primates by Mycoplasma fermentans (incognitus strain)

Four silvered leaf monkeys inoculated with Mycoplasma fermentans (incognitus strain) showed wasting syndromes and died in 7-9 months. Infected animals had a late and transient antibody response to mycoplasmal infection. Three monkeys revealed periodic mycoplasmal antigenemia. The one that had the most persistent antigenemia failed to mount a detectable antibody response and was the first to die of the infection. The control monkey was killed 8 months later, after the last of the infected animals had died, and revealed no evidence of seroconversion or antigenemia. Polymerase chain reaction, immunohistochemical, and electron microscopic studies identified systemic infections of M. fermentans in the infected animals. No other opportunistic infection or neoplastic disease was found. It is interesting to note the absence of an inflammatory reaction to the large number of mycoplasmas in the infected tissues. M. fermentans (incognitus strain) apparently suppressed normal inflammatory or immune responses, produced wasting syndromes, and caused a fatal systemic infection in these monkeys.

Further characterization of 5-HT- and 5-HT3 receptor agonists'-stimulated phosphoinositol phosphates accumulation

The calcium requirement for serotonin (5-HT)- and the 5-HT3 receptor agonists, 2-Me-5-HT- and PBG-dependent breakdown of phosphatidyl inositol has been examined in the rat fronto-cingulate cortex. The omission of added Ca2+ from the Kreb's incubation medium reduced the [3H]inositol phosphate accumulation from pre-labelled phospholipids. Removal of Ca2+ by pre-incubation with EGTA (0.5 mM), as well as the addition of the calcium channel blocker, lanthanum (10 microM), abolished the 5-HT- and the 5-HT3 receptor agonists'-stimulated phosphoinositide (PI) response. By contrast, the calcium ionophores, A 23187 and Ionomycin (both at 30 microM) stimulated PI hydrolysis, and this effect was additive to the increased PI turnover induced by 5-HT, 2-Me-5-HT and PBG. The increase in phosphoinositide hydrolysis induced by 5-HT and 2-Me-5-HT was significantly inhibited by phorbol dibutyrate (PDBu) and phorbol myristate acetate, indicating that the activation of protein kinase C (PKC) may provide negative feedback to the PI response induced by 5-HT and 2-Me-5-HT-stimulated PI metabolism was reversed by the PKC inhibitors, staurosporine, calphostin C and chelerythrine (all at 10 microM), however, Pertussis toxin (0.5 and 1 microgram) had no effect on either 5-HT's or 2-Me-5-HT's increased stimulation of PI hydrolysis, suggesting that this response is not associated to a Gi GTP binding protein.

Identification of a putative infC-rpmI-rplT operon flanked by long inverted repeats in Mycoplasma fermentans (incognitus strain)

A specific 1542-bp DNA fragment was amplified from Mycoplasma fermentans (incognitus strain) using a unique 23-nucleotide (nt) synthetic deoxyribonucleotide (oligo) (5'-TCCAAAAAGTCCGGAATTTGGGG) as the primer pair in the polymerase chain reaction (PCR). The 23-nt sequence is part of the 29-bp terminal inverted repeat (IR) which forms the left potential stem-and-loop (s&l) structure of the previously identified M. fermentans insertion-sequence(IS)-like genetic element [Hu et al., Gene 93 (1990) 67-72]. The amplified DNA was cloned and sequenced. A pair of 27-bp IR containing the 23-nt synthetic oligo was identified at both termini. Between the IR, there are four potential open reading frames (ORFs) which are arranged adjacent to each other in the order, ORF-1, ORF-2, ORF-3 and ORF-4, with parts of ORF-1 and ORF-2 overlapping. The deduced amino acid (aa) sequences of ORF-2, ORF-3 and ORF-4 are 34 to 60% identical to the translation initiation factor IF3 (encoded by the infC gene), ribosomal proteins L35 (rpmI gene) and L20 (rplT gene) of Escherichia coli and Bacillus stearothermophilus, respectively. In bacteria, the infC-rpmI-rplT genes are organized to function as an operon. There are multiple sites with promoter-like sequences identified upstream from the putative infC gene in the mycoplasma closely resembling the gene arrangement in the bacterial operon. All three genes of ORF-2, ORF-3 and ORF-4 are preceded individually by a strong appropriately spaced (7 and 10 bp) putative Shine-Dalgarno sequence (5'-AAGGA).(ABSTRACT TRUNCATED AT 250 WORDS)

Detection and isolation of Mycoplasma fermentans from urine of human immunodeficiency virus type 1-infected patients

Mycoplasma fermentans (incognitus strain) has been linked with acquired immunodeficiency syndrome-associated nephropathy. Ten (23%) of 43 urine sediment specimens from 40 human immunodeficiency virus (HIV)-positive patients at different stages of acquired immunodeficiency syndrome disease tested positive in the polymerase chain reaction using a primer pair found in the insertion sequences specific to M fermentans. Mycoplasma fermentans was isolated from two HIV-positive patients' urine sediment specimens and on a repeated basis from one. All three culture-positive urine sediment specimens tested positive in the polymerase chain reaction. Fifty urine sediment specimens from age-matched HIV-negative healthy controls tested negative for M fermentans by polymerase chain reaction. Mycoplasma fermentans was not isolated from any of the control urine sediment specimens. Our results show a high prevalence of M fermentans in urine sediment specimens from HIV-positive patients but not from urine sediment specimens of HIV-negative healthy controls.

A new chemotherapy regimen for treatment of Hodgkin's disease associated with minimal genotoxicity

Recently, the combination chemotherapy Novantrone, Oncovin, Velban, Prednisone [NOVP] was developed by The University of Texas M. D. Anderson Cancer Center for treatment of Hodgkin's disease [HD]. Preliminary clinical results show that NOVP is as effective as the traditional Mechlorethamine, Oncovin, Procarbazine, Prednisone [MOPP] regimen in achieving remission, but with fewer side-effects. To determine if NOVP is genotoxic, we studied the induction of chromosome breaks and sister chromatid exchanges [SCEs] in lymphocytes of 42 HD patients both before and during NOVP treatment. Furthermore, in vitro bleomycin treatment was used to unmask potential single-stranded DNA breaks inducted by the therapy. Our results showed that NOVP did not cause elevated levels of chromosome or single-stranded DNA breaks, or SCEs. These results together with previous findings that NOVP caused minimal acute and gonadal toxicities suggest that NOVP is less toxic than MOPP. Therefore, this new regimen shows promise as an effective and minimally toxic regimen for treatment of HD.

Biochemical characterization of phosphoinositide hydrolysis stimulated by 5-HT3 receptor agonists

Serotonin (5-HT) stimulates phosphoinositide (PI) turnover in rat fronto-cingulate cortical slices and is probably mediated through the activation of both 5-HT2 and 5-HT3 receptors. We have extended these findings and have assessed whether the increased stimulation of PI turnover is secondary to 5-HT stimulated arachidonate metabolism or to the release of another neurotransmitter. Incubation of the cortical slices by the two 5-HT3 receptor agonists, 2-methyl-serotonin (2-Me-5-HT) and phenylbiguanide (PBG), significantly decreases serotonin-stimulated phosphoinositide turnover, indicating that activation of 5-HT3, receptors by 2-Me-5-HT and PBG caused the desensitized PI hydrolysis to 5-HT. Indomethacin did not affect the increased PI hydrolysis induced by 5-HT, 2-Me-5-HT and PBG, suggesting that neither cyclooxygenase nor lipoxgenase activity is required for the PI response and that it is independent of arachidonic acid metabolism. The stimulation in PI turnover induced by 5-HT and the 5-HT3 receptor agonists was not potentiated by proteinase inhibitors suggesting that the release of a peptide neurotransmitter is not involved in the PI response. In addition, the effects of 5-HT, 2-Me-5-HT and PBG on PI turnover are additive to the effect of KCl and veratrine. In conclusion, our results indicate that the action of 2-Me-5-HT and PBG on PI turnover is direct.

High frequency of antibodies to Mycoplasma penetrans in HIV-infected patients

Mycoplasma penetrans, a novel mycoplasma isolated from HIV-1-infected patients with AIDS, has pathogenic properties associated with in-vivo virulence. Enzyme-linked immunosorbent assay and western blotting detected a more than 100 times higher frequency of antibodies to the mycoplasma in serum from HIV-1-infected patients with AIDS (40%) than from HIV-negative controls (0.3%). Serum from 20% of HIV-1-infected, symptom-free individuals also had M penetrans specific antibodies. The antibodies' major immunoreactivity was directed against P35 and P38, the two main lipid-associated membrane protein antigens of the organism. Patients attending sexually transmitted disease clinics had a low frequency of antibody (0.9%). None of 178 HIV-negative patients with different non-AIDS diseases, many associated with immune dysfunction and/or low white cell counts, tested positive for the antibodies. M penetrans, apparently not a commensal and not a simple opportunist, is uniquely associated with HIV-1 infection and AIDS.