MPTP-induced "parkinsonism" in the goldfish.
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1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
Biomedical subjects
M Levine
Publications and source records attributed to M Levine.
Construction of a genetically defined Salmonella typhi Ty2 aroA, aroC mutant for the engineering of a candidate oral typhoid-tetanus vaccine.
The construction of a Salmonella typhi Ty2 strain harbouring defined deletions in both the aroA and aroC genes is described. These deletions have been fully defined at the molecular level by DNA sequencing and have been introduced in such a way that no foreign DNA remains in the S. typhi genome. This strain is attenuated in mice when given by the intraperitoneal route suspended in hog gastric mucin and is attenuated to a similar level to strains harbouring deletions in aroA or aroC alone indicating that both lesions are capable of attenuating independently. We have used this defined S. typhi aroA aroC strain to express stably a non-toxic 50 kDa fragment of tetanus toxin (fragment C) from a gene incorporated into the chromosome. This strain has the advantage of harbouring no antibiotic-resistance markers and we consider it to be a candidate bivalent oral typhoid-tetanus vaccine.
Administration, Oral↗
Spermatogenesis and reproductive performance following human accidental exposure to bromine vapor.
The present study was undertaken to evaluate spermatogenesis and reproductive performance among 8 men and their spouses following accidental exposure to bromine vapor. Of the three cases with oligo-terato-asthenozoospermia (OTA), one had been diagnosed prior to and unrelated to the event. Mild OTA and unimpaired reproductive performance characterized the other two cases. Plasma levels of the follicle stimulating hormone and luteinizing hormone were normal in all men. One first-trimester abortion and one late abortion (due to chorioamnionitis) occurred among the 5 pregnancies conceived shortly after the accident. Results of the present study suggest a mild degree of spermatogenic suppression and impaired reproductive performance following paternal exposure to bromine vapor during the above described accident. However, due to the small size of the study cohort, a confidential cause-result linkage could not be established.
Accidents, Occupational↗
Ectopic expression of the Drosophila tramtrack gene results in multiple embryonic defects, including repression of even-skipped and fushi tarazu.
The tramtrack (ttk) gene of Drosophila encodes 69-kDa and 88-kDa proteins through alternative splicing of the primary ttk transcript. The two proteins share a common amino-terminal sequence, but contain different carboxy-terminal portions, each of which has a distinct zinc finger domain with a unique DNA binding specificity. The 69-kDa ttk protein has been shown to bind multiple sites within important regulatory elements of the pair-rule genes even-skipped (eve) and fushi tarazu (ftz), and it has been suggested that this protein may function as a repressor of ftz transcription. Here we present evidence that the 69-kDa ttk protein can indeed repress expression not only of ftz, but also of eve. Ectopic expression of the 69-kDa protein, but not of the 88-kDa form, was found to nearly abolish the striped patterns of expression of both eve and ftz in transgenic embryos. These findings, coupled with our detection of significant levels of ttk protein in ovaries and 0-2-h embryos, support the idea that maternally supplied ttk protein serves to prevent premature activation of eve and ftz, thereby helping to establish the timing of the onset of zygotic expression of these two genes. Furthermore, gross defects in the larval cuticle resulting from misexpression of the 69-kDa protein suggest that this protein performs additional functions in the early embryo.
Animals↗
Delayed health sequelae of accidental exposure to bromine gas.
The delayed health effects from accidental exposure to bromine vapors in a group of six people were evaluated. During the acute exposure, they had only some respiratory symptoms and skin burns of first to second degree involving small areas. All were treated in one hospital and released within 1-4 d. Six to 8 wk later, some still had health complaints such as cough, shortness of breath, chest tightness, eye irritation, headache, dizziness, fatigue, and memory, sleep, and sexual disturbances, but no objective laboratory or clinical evidence of effects. Mechanisms that might have led to manifestations of such complaints 1-2 mo after the accident are discussed and possible ways to alleviate similar situations are suggested.
Accidents, Traffic↗
Safety and immunogenicity of Salmonella typhi Ty21a liquid formulation vaccine in 4- to 6-year-old Thai children.
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Age Factors↗
A parkinsonian syndrome induced in the goldfish by the neurotoxin MPTP.
Parkinson's disease has been modeled in humans, lower primates, and to a lesser extent in some other vertebrates by administration of the potent neurotoxin MPTP (1-methyl-4-phenyl-1,2,3,6 tetrahydropyridine). The MPTP model has thus drawn considerable attention as a system to search for anti-Parkinson's disease drugs, although the cost and scarcity of primates has limited extensive applications. We now report that a parkinsonian syndrome can be elicited in the common goldfish (Carassius auratus) by a single dose of MPTP. The syndrome is characterized by profound bradykinesia (slow movement), the full extent of which is reached 3 days after MPTP administration. The reduction in movement is paralleled by loss of dopamine and norepinephrine from the forebrain and midbrain and in other brain regions as well. The toxic oxidative product of MPTP, MPP+, is also accumulated predominantly in forebrain and midbrain, and pretreatment with the monoamine oxidase blocker tranylcypromine substantially reduces accumulation of the toxic metabolite. A barely perceptible coarseness in balance adjustment also occurs in treated animals. The MPTP-treated goldfish recover normal movement and normal brain monoamine levels within 10-13 days after administration of the drug. We interpret these and other data to indicate that MPTP can induce a Parkinson's disease-like syndrome in the goldfish that is similar in many aspects to the syndrome induced by MPTP in humans and other primates. This remarkable parallel may permit the goldfish to supplement expensive and scarce primates for the purpose of searching and screening neuroprotective drugs with specific relevance to Parkinson's disease.
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
dorsal-twist interactions establish snail expression in the presumptive mesoderm of the Drosophila embryo.
The first step in the differentiation of the Drosophila mesoderm is the activation of two regulatory genes, twist (twi) and snail (sna), in ventral regions of early embryos. sna is a transcriptional repressor that is uniformly expressed throughout the presumptive mesoderm. Its sharp lateral limits help to establish the boundary between the mesoderm and neuroectoderm. Genetic studies suggest that sna is a target of the dorsal (dl) morphogen, and this interaction provides a model for determining how a morphogen gradient establishes a sharp, on/off threshold response. We present evidence that dl and twi directly activate sna expression. Site-directed mutagenesis of dl- and twi-binding sites within defined regions of the sna promoter suggest that the two proteins (containing the Rel and helix-loop-helix domains, respectively) function multiplicatively to ensure strong, uniform expression of sna, particularly in ventral-lateral regions where there are diminishing amounts of dl. These results are consistent with the possibility that the sharp sna borders are formed by multiplying the shallow dl gradient and the steeper twi gradient.
Animals↗
The dorsal gradient morphogen regulates stripes of rhomboid expression in the presumptive neuroectoderm of the Drosophila embryo.
rhomboid (rho) encodes a putative transmembrane receptor that is required for the differentiation of the ventral epidermis. It is initially expressed before the completion of cellularization in lateral stripes within the presumptive neuroectoderm. Here, we present evidence that the maternal morphogen dorsal (dl) acts in concert with basic helix-loop-helix (b-HLH) proteins, possibly including twist (twi), to activate rho in both lateral and ventral regions. Expression is blocked in ventral regions (the presumptive mesoderm) by snail (sna), which is also a direct target of the dl morphogen. A 300-bp region of the rho promoter (the NEE), which is sufficient for neuroectoderm expression, contains a cluster of dl and b-HLH activator sites that are closely linked to sna repressor sites. Mutations in these binding sites cause genetically predicted changes in the levels and limits of rho expression. In particular, the disruption of sna-binding sites causes a derepression of the pattern throughout ventral regions, providing evidence that sna is directly responsible for establishing the mesoderm/neuroectoderm boundary before gastrulation. The tight linkage of activator and repressor sites in the rho NEE is similar to the arrangement of binding sites observed in the even-skipped stripe 2 element, which is regulated by bicoid (bcd). This suggests that the dl and bcd morphogens use a similar mechanism to make stripes in the Drosophila embryo.
Animals↗
Prophylactically equivalent doses of Enoxaparin and unfractionated heparin inhibit in vivo coagulation to the same extent.
This study compared how Enoxaparin and unfractionated (UF) heparin influenced in vivo coagulation in patients randomized to receive, by twice daily subcutaneous injections, either 30 mg of Enoxaparin or 7500 I.U. of UF heparin after elective hip surgery. These two regimens were equally effective in reducing the incidence of post-operative deep vein thrombosis DVT. We compared the concentrations of endogenous thrombin-antithrombin III in pre- and post-surgical plasmas to determine how each prophylactic regimen influenced prothrombinase activity in vivo, and found the same concentrations of endogenous thrombin-antithrombin III in post-heparin and post-Enoxaparin plasmas. However, significantly higher concentrations of endogenous thrombin-antithrombin III were found in pre- and post-surgical plasmas of patients who developed post-operative DVT than the levels found in comparable plasmas of patients who remained DVT-negative, regardless of the drug received for prophylaxis. Human factor Xa was added to an equal volume of each patient's plasmas and the amount of added enzyme inactivated by antithrombin III measured using an enzyme-linked immunosorbent assay for factor Xa-antithrombin III. Post-heparin and post-Enoxaparin plasmas inactivated approximately 4 times more factor Xa than the pre-surgical plasmas, regardless of the clinical outcome. Thus, before and after surgery, a higher than normal in vivo prothrombinase activity may be a significant risk factor for developing post-operative DVT.
Antithrombin III↗
Genetic analysis of type-specific antigenic determinants of herpes simplex virus glycoprotein C.
Herpes simplex virus type 1 (HSV-1) glycoprotein C (gC-1) elicits a largely serotype-specific immune response directed against previously described determinants designated antigenic sites I and II. To more precisely define these two immunodominant antigenic regions of gC-1 and to determine whether the homologous HSV-2 glycoprotein (gC-2) has similarly situated antigenic determinants, viral recombinants containing gC chimeric genes which join site I and site II of the two serotypes were constructed. The antigenic structure of the hybrid proteins encoded by these chimeric genes was studied by using gC-1- and gC-2-specific monoclonal antibodies (MAbs) in radioimmunoprecipitation, neutralization, and flow cytometry assays. The results of these analyses showed that the reactivity patterns of the MAbs were consistent among the three assays, and on this basis, they could be categorized as recognizing type-specific epitopes within the C-terminal or N-terminal half of gC-1 or gC-2. All MAbs were able to bind to only one or the other of the two hybrid proteins, demonstrating that gC-2, like gC-1, contains at least two antigenic sites located in the two halves of the molecule and that the structures of the antigenic sites in both molecules are independent and rely on limited type-specific regions of the molecule to maintain epitope structure. To fine map amino acid residues which are recognized by site I type-specific MAbs, point mutations were introduced into site I of the gC-1 or gC-2 gene, which resulted in recombinant mutant glycoproteins containing one or several residues from the heterotypic serotype in an otherwise homotypic site I background. The recognition patterns of the MAbs for these mutant molecules demonstrated that (i) single amino acids are responsible for the type-specific nature of individual epitopes and (ii) epitopes are localized to regions of the molecule which contain both shared and unshared amino acids. Taken together, the data described herein established the existence of at least two distinct and structurally independent antigenic sites in gC-1 and gC-2 and identified subtle amino acid sequence differences which contribute to type specificity in antigenic site I of gC.
Amino Acid Sequence↗
A cell-free recombination system for site-specific integration of multigenic shuttle plasmids into the herpes simplex virus type 1 genome.
This report describes a novel method for complementation studies of defective herpes simplex virus (HSV) genes. Viral test gene and nonviral reporter gene cassettes were rapidly integrated into the HSV genome in a site-specific and reversible manner by using the P1 phage-based Cre-lox recombination system. Shuttle plasmids contained a functional loxP recombination site, an expressible form of the bacterial lacZ gene, and a copy of the wild-type glycoprotein B (gB) gene or double mutant gB allele containing both a temperature-sensitive (ts) mutation and a syncytium (syn)-forming mutation. A recipient viral genome, K delta T::lox1, was constructed from the HSV type 1 (syn) gB-deficient mutant virus, K delta T, by marker transfer of the loxP recombination site into the viral thymidine kinase locus. Shuttle plasmids of up to 12.9 kb in length were recombined with high efficiency (11 to 20%) into the K delta T::lox1 genome in cell-free, Cre-mediated recombination reactions. Expression of a functional wild-type or double mutant gB polypeptide complemented the nonfunctional polypeptide expressed from the deleted, normal gB locus and allowed production of either wild-type or Syn- plaques on Vero cells. The latter recombinant virus was also ts for growth. The ability to express viral genes from plasmids which can be shuttled into and out of the HSV genome in cell-free recombination reactions makes this a powerful method for performing genetic studies of the biologic properties of viral gene products.
Animals↗
The relationship between environmental temperature, metabolic rate, sleep state, and evaporative water loss in infants from birth to three months.
We have investigated the effect of changing environmental temperature on metabolic rate, sleep state, and water loss in a longitudinal study of 22 lightly clothed babies from 2 d to 3 mo of age. Studies were performed in a modified barometric plethysmograph while recording sleep state, oxygen consumption, and skin and axillary temperatures. Oxygen consumption was higher in rapid eye movement sleep than in quiet sleep at all ages and varied widely between infants at each temperature. Within the first week, there was a 19% rise in oxygen consumption on cooling to 19-22 degrees C during rapid eye movement sleep and a 6% rise during quiet sleep. The median duration of quiet sleep periods was reduced from 17 to 12 min on cooling within the first week. No such change was seen at 1, 2, and 3 mo. Axillary temperature was reduced at 3 mo during cooling. This may be a part of normal patterns of change in temperature during sleep, unrelated to cooling. At each age, total evaporative water loss fell linearly with falling environmental temperature both within and below the temperature range at which metabolic rate was minimal. The evaporative water losses were greater than expected and suggested that sweating was occurring, both at temperatures at which metabolic rate was minimal and at those at which it was increased. The metabolic response to cooling and the process of sweating appear to be in dynamic equilibrium across this temperature range. Thus, it was not possible to define a temperature range over which both metabolic rate and evaporative water loss were at minimum values.
Body Temperature Regulation↗
The bicoid and dorsal morphogens use a similar strategy to make stripes in the Drosophila embryo.
The anterior-posterior (A-P) and dorsal-ventral (D-V) axes of the early Drosophila embryo are established by two key maternal morphogens: bicoid (bcd) and dorsal (dl), respectively. The bcd protein is expressed in a broad concentration gradient along the A-P axis, with peak levels present at the anterior pole, while dl is expressed in a gradient along the D-V axis with peak levels along the ventral surface. The two morphogens are unrelated and their gradients are formed by distinct processes. Nonetheless, we have obtained evidence that they generate sharp on/off stripes of target gene expression through a similar mechanism. Both morphogens establish overlapping patterns of transcriptional activators and repressors in the early embryo. The activators and repressors bind to closely linked sites within short (300 to 500 bp) target promoter elements that have the properties of on/off switches. The activators act in concert with the morphogen to define a broad region where target genes can be initiated. Borders of target gene expression are established by the repressors, resulting in the formation of stripes.
Animals↗
Ascorbic acid and reaction kinetics in situ: a new approach to vitamin requirements.
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Animals↗
Opioid receptor modulation of postexercise hypotension.
Previous studies of both hypertensive and normotensive individuals have indicated a prolonged reduction in blood pressure for several hours after aerobic exercise. In related studies of spontaneously hypertensive rats, this postexercise hypotension has been prevented with naloxone. The purpose of the present investigation was to examined whether the postexercise hypotension may be reversed by antagonism of opioid sensitive receptors with naloxone in normotensive humans. Eight males 22-34 yr of age, participated in two 60-min cycling trials at 60% of VO2 peak, followed by 29 min of recovery. Beginning at 7-min recovery, naloxone or saline (control) was administered intravenously through an indwelling catheter. Blood pressure and heart rate were monitored every 15 min during exercise and every 2 min during recovery. Heart rate was significantly elevated (P < 0.05) over basal levels for the first 11 min of recovery, but from 13 to 29 min was not different from that measured at rest. In both trials, after 11 min of recovery, systolic and mean arterial blood pressures were significantly (P < 0.05) lower than pre-exercise levels (9 +/- 1 mm Hg and 4 +/- 1 mm Hg, respectively). Injection of naloxone (0.1 mg.kg-1) reversed the hypotensive response. However, the reversal was transient, lasting from minutes 15 to 27. Since naloxone reverses postexercise hypotension, opioid sensitive receptors appear to be involved in the reduction in systolic blood pressure following a single bout of submaximal exercise in normotensive humans.
Adult↗
[Typhoid fever in school children: by what measures is the modification of the clinical course due to oral vaccination?].
The clinical course of infection by Salmonellae was compared between patients who had been vaccinated against typhoid fever using the Ty21a vaccine and those who had not. Of 2566 bacteriological confirmed cases 84% were infected with S typhi, 14% with S paratyphi B and 2% with S paratyphi A. Among patients with typhoid fever, 34% were treated in hospital, 3.5% had relapses, 5.4% developed complications and 1 patient died (0.05%). Among patients with paratyphoid fever, 18% were treated in hospital, 0.6% had relapses, 1.4% developed complications and there were no deaths. These figures were similar among vaccinated and non-vaccinated cases. A slightly greater proportion of vaccinated cases were treated in hospital (38 vs 30%). Thus, use of oral vaccination against typhoid fever does not alter the clinical course of infection with Salmonellae.
Administration, Oral↗
Selective inhibition of rat hepatic microsomal cytochrome P-450. I. Effect of the in vivo administration of cimetidine.
Cimetidine is considered to be a general inhibitor of cytochrome P-450 enzymes, but there is indirect evidence that certain cytochrome P-450 enzymes are not inhibited by cimetidine. The purpose of this study was to determine whether cimetidine, when administered in vivo to adult male Wistar rats, selectively inhibits hepatic microsomal cytochrome P-450 enzymes. Uninduced, phenobarbital (PB)-induced and dexamethasone (DEX)-induced rats were sacrificed 90 min after treatment with a single i.p. dose of cimetidine HCI (150 mg/kg) or saline. Hepatic microsomes were prepared, and aminopyrine N-demethylase (APND), pentoxyresorufin O-dealkylase (PROD), erythromycin N-demethylase (EMND) activities and oxidation of testosterone were determined. In addition, immunoinhibition studies with a polyclonal antibody monospecific for cytochrome P-450IIC11 were performed. Cimetidine treatment inhibited APND, PROD and EMND activities to a greater extent in microsomes from uninduced rats than in those from PB- or DEX-induced rats, suggesting that the induced cytochrome P-450 enzymes were less affected by cimetidine than were those in uninduced rats. Cimetidine treatment inhibited testosterone 2 alpha-hydroxylase activity by 65, 73 and 46%, respectively, in microsomes from uninduced, PB-induced and DEX-induced rats. The antibody completely inhibited testosterone 2 alpha-hydroxylase activity in the three groups of microsomes, indicating that this activity is specific for cytochrome P-450IIC11 in all these cases. Neither cimetidine treatment nor the antibody inhibited microsomal testosterone 2 beta-, 6 beta-, 7 alpha- or 16 beta-hydroxylase activity.(ABSTRACT TRUNCATED AT 250 WORDS)
Aminopyrine N-Demethylase↗