Psychological aspects of human cloning and genetic manipulation: the identity and uniqueness of human beings.

Human cloning has become one of the most controversial debates about reproduction in Western civilization. Human cloning represents asexual reproduction, but the critics of human cloning argue that the result of cloning is not a new individual who is genetically unique. There is also awareness in the scientific community, including the medical community, that human cloning and the creation of clones are inevitable. Psychology and other social sciences, together with the natural sciences, will need to find ways to help the healthcare system, to be prepared to face the new challenges introduced by the techniques of human cloning. One of those challenges is to help the healthcare system to find specific standards of behaviour that could be used to help potential parents to interact properly with cloned babies or children created through genetic manipulation. In this paper, the concepts of personality, identity and uniqueness are discussed in relationship to the contribution of twin studies in these areas. The author argues that an individual created by human cloning techniques or any other type of genetic manipulation will not show the donor's characteristics to the extent of compromising uniqueness. Therefore, claims to such an effect are needlessly alarmist.

Laboratory-dependent bacterial ecology: a cautionary tale.

Although laboratory dependence is an acknowledged problem in microbiology, it is seldom intensively studied or discussed. We demonstrate that laboratory dependence is real and quantifiable even in the popular model Escherichia coli. Here laboratory effects alter the equilibrium composition of a simple community composed of two strains of E. coli. Our data rule out changes in the bacterial strains, chemical batches, and human handling but implicate differences in growth medium, especially the water component.

Mechanisms of acid-catalyzed Z/E isomerization of imines.

The kinetics and mechanism of acid-catalyzed Z/E isomerization of O-methylbenzohydroximoyl chloride (1Za and 1Ea), methyl O-methylbenzohydroximate (1Zb and 1Eb), ethyl O-methylbenzohydroximate (1Zc and 1Ec and five para and meta substituted derivatives), O-methylcinnamohydroximoyl chloride (2Za and 2Ea), and methyl O-methylcinnamohydroximate (2Zb and 2Zb) have been investigated. The kinetics of Z/E isomerization of these imines have been studied in glacial acetic acid (1Ea and 1Zc) and in dioxane solutions containing HCl, trifluoromethanesulfonic acid, or tetrafluoroboric acid (1Ea, 1Zb, 2Ea, and 2Zb). The isomerization takes place by either (a) rotation about the carbon-nitrogen double bond of the protonated imine (iminium ion rotation) or (b) nucleophilic attack on the protonated imine to form a tetrahedral intermediate that undergoes stereomutation and loss of the nucleophile (nucleophilic catalysis). The hydroximoyl chlorides 1Eaand 2Ea only isomerize by the nucleophilic catalysis mechanism. The hydroximate 1Zb appears to be capable of isomerizing by either mechanism. The hydroximate 2Zb may be isomerizing only by iminium ion rotation. Theoretical calculations support the notion that increased conjugation in the protonated imine increases the rate of iminium ion rotation.

[Neurocysticercosis and Lennox-Gastaut syndrome: case report]. / Neurocisticercose e síndrome de Lennox-Gastaut: relato de caso.

Report of a girl with the epileptic, hydrocephalic and encephalitic form of neurocysticercosis, diagnosed by cerebrospinal fluid and computed tomography exams, during her second year of life and an evolution with multiple types of seizures, prolonged periods of intracranial hypertension due to obstruction in the ventriculoperitoneal shunt, psychomotor regression and blindness until she was 10 years old, when the Lennox-Gastaut syndrome was diagnosed. Nowadays the patient is 16 years old and presents complex partial seizures with automatism not completely controlled with clobazan and oxcarbazepine, associated to left spastic hemiparesis, universal hyperreflexia, psychomotor agitation, self-mutilation, amaurosis and severe mental retardation. The association between neurocysticercosis and Lennox-Gastaut syndrome was first described in 1973 by Frochtengarten & Scarante in a Brazilian girl with a similar clinical picture.

Clinical aspects of neurocysticercosis in children.

The purpose of this report was to evaluate the clinical aspects of neurocysticercosis in children from a Brazilian region. A retrospective study of 25 children with this neuroparasitosis was performed. The diagnosis was based on clinical, cerebrospinal fluid, and neuroimaging findings. The patients were predominantly male (72%), were 1 to 11 years of age (average = 8 years, 6 months), and most resided in urban areas (68%). The more frequent manifestations were epileptic seizures (72%), headache (60%), learning disability (24%), behavioral changes (12%), psychomotor involution (8%), and intracranial hypertension (4%). The neurologic examination was normal in 80% of the patients. Twenty-two children received only symptomatic drugs. Three patients underwent treatment with cysticidal drugs, one with praziquantel and two with albendazole, with complete remission of the signs in one patient (33%) and improvement in two others (67%). Of the 25 patients, 43.4% had remission and 47.8% had improvement. We emphasize the need to consider neurocysticercosis as a differential diagnosis in children coming from endemic areas and presenting with learning disabilities, behavioral changes, and psychomotor involution. The clinical aspects in most of the children from the Botucatu region suggest a spontaneous resolution of neurocysticercosis without the need for cysticidal treatment.

Analysis of cloned structural and regulatory genes for carbohydrate utilization in Pseudomonas aeruginosa PAO.

Five of the genes required for phosphorylative catabolism of glucose in Pseudomonas aeruginosa were ordered on two different chromosomal fragments. Analysis of a previously isolated 6.0-kb EcoRI fragment containing three structural genes showed that the genes were present on a 4.6-kb fragment in the order glucose-binding protein (gltB)-glucokinase (glk)-6-phosphogluconate dehydratase (edd). Two genes, glucose-6-phosphate dehydrogenase (zwf) and 2-keto-3-deoxy-6-phosphogluconate aldolase (eda), shown by transductional analysis to be linked to gltB and edd, were cloned on a separate 11-kb BamHI chromosomal DNA fragment and then subcloned and ordered on a 7-kb fragment. The 6.0-kb EcoRI fragment had been shown to complement a regulatory mutation, hexR, which caused noninducibility of four glucose catabolic enzymes. In this study, hexR was mapped coincident with edd. A second regulatory function, hexC, was cloned within a 0.6-kb fragment contiguous to the edd gene but containing none of the structural genes. The phenotypic effect of the hexC locus, when present on a multicopy plasmid, was elevated expression of glucokinase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydratase, and 2-keto-3-deoxy-6-phosphogluconate aldolase activities in the absence of inducer.

Effect of in vitro transcription on cruciform stability.

We have investigated the effect of in vitro transcription on cruciform stability. Replicative form DNA of phiX174 strain ins6240, containing a 48 bp synthetic palindrome in the J-F intercistronic region, was supercoiled in vitro to mean negative superhelical densities (sigma) ranging from 0 to 0.15. The presence of cruciforms was probed by limited digestion with the single-strand specific nuclease Bal31. The 48 bp palindrome was extruded at a mean sigma = -0.05, but only after heating the DNA. An in vitro transcription reaction with E. coli RNA polymerase and [alpha-32P]UTP gave identical transcripts with heated or unheated template DNA. The synthetic cruciform was stable upon binding of the RNA polymerase to the template, but it was destabilized upon movement of the transcription complex along the template. Transcription of unheated templates did not result in cruciform formation. We propose that cruciform structures in supercoiled template DNAs present no hindrance to RNA polymerase, and thus have no detectable effect on transcription elongation in vitro.

In vivo binding of 2,3,6,2',3',6'-hexachlorobiphenyl and 2,4,5,2',4',5'-hexachlorobiphenyl to mouse liver macromolecules.

The role of metabolic activation in the binding of polychlorinated biphenyls (PCBs) to cellular macromolecules was investigated in vivo by comparing the relative binding of 2,4,5,2',4',5'-[U-14C]hexachlorobiphenyl (2,4,5), a slowly metabolized PCB, with that of 2,3,6,2',3',6'[U-14C]hexachlorobiphenyl (2,3,6), a rapidly metabolized PCB, and the appropriate controls. Each hexachlorobiphenyl was administered to mice, orally for 5 days (7.28 mg/kg/day). Following the dosing schedule, animals were killed at 1, 5 and 8 days. The concentration of each PCB was determined in liver, muscle and kidney and in purified macromolecules isolated from those tissues. The concentration of 2,4,5 was consistently higher than the concentration of 2,3,6 in all tissues studied. However, the amount of 2,3,6 bound to the purified macromolecules was consistently at least one order of magnitude greater than that of 2,4,5. The greatest binding was observed in RNA followed by protein and DNA, respectively. The purity of the macromolecules and the presence of PCB-derived radioactivity at the monomer level were confirmed. This is the first report of 14C-labeled PCB being bound to purified RNA, DNA, and proteins isolated from the tissues of animals treated in vivo. The binding is thought to be covalent and to be the result of metabolic activation.

The ribonucleic acids of Crithidia fasciculata.

Crithidia fasciculata ribosomes were found to be 80S and to dissociate into 58 and 41S subunits; on 5 to 50% sucrose gradients, rRNA was separated into 25, 18, and 5S components. The molecular sizes of the heavier rRNA species, estimated by polyacrylamide gel electrophoresis were 1.24 and 0.84 M (X 10(6) daltons). The 25S RNA has a tendency to interact with the 18S RNA to give a complex that is difficult to separate by sucrose gradient centrifugation. The 25S RNA is also unstable and dissociates into 0.73 and 0.57 M components. The 18S RNA has molecular size (0.84 M) higher than the 0.7 M reported for most eukaryotes, but similar to that of Euglena and Amoeba. Ribosomal RNA hybridized 0.29% of the nuclear DNA. Mitochondrial RNA, extracted by a rapid procedure was resolved into 16 and 5S components in sucrose gradients.

Distribution and excretion of 2,4,5,2',4',5'-hexabromobiphenyl, the major component of Firemaster BP-6.

The intestinal absorption, distribution, and excretion of the major component of Firemaster BP-6,2,4,5,2',4',5'-hexabromobiphenyl, has been studied in the male rat. This polybrominated biphenyl was readily absorbed from the intestine, initially distributed throughout the body, and eventually stored primarily in the adipose tissue, was not subject to appreciable metabolism, and was excreted almost exclusively in the feces and at a very slow rate. Approximately 90% of an oral dose was absorbed from the intestine, and extrapolation of the rate of excretion to infinity indicates that less than 10% of the total dose would ever be excreted.