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PubMed1999

[Advances in understanding of clinical presentations and molecular mechanisms of triplet repeat diseases].

Triplet repeat diseases are diseases caused by unstable expansion of trinucleotide repeats in the causative genes. Identification of the causative genes has made it possible to understand the clinical presentations and molecular mechanisms of neurodegeneration caused by expanded triplet repeat diseases. In the triplet repeat diseases caused by expansion of CAG trinucleotide repeats, the CAG repeats code for polyglutamine stretches. Evidences, which indicate that proteins with expanded polyglutamine stretches result in aggregate formation and induce apoptosis, are accumulating, and it is expected that development of therapeutic measures for triplet repeat diseases will become a reality in the near future.

Age of Onset↗
PubMed2000

[Triplet repeat disease from the aspect of psychiatric disease].

Since 1991, about 20 triplet repeat expansion disorders have been reported. They are clinically characterized by anticipation, worsening severity or earlier age at the onset with each succeeding generation, and imprinting, a process whereby specific genes are differentially, marked during parental gametogenesis, resulting in their differential expression. The anticipation in psychoses was pointed out in the 19th century, but it was ignored because no one knew the mechanism at that time. The discovery of triplet repeat expansion diseases has reawakened interest in anticipation in psychiatric diseases. Anticipation has been confirmed in schizophrenia, mood disorders, and anxiety disorders. Molecular approaches have been taken to reveal the involvement of a triplet repeat expansion mechanism in psychoses. Most efforts have been made for CAG-type trinucleotide repeats. So far, most results did not support a trinucleotide repeat expansion mechanism also in psychoses. One plausable explanation for the "false positive" result is the presence of CAG trinucleotide repeats, which are highly polymorphic but not associated with an obvious abnormal phenotype. The screening for triplet repeats besides those of the CAG type remain to be performed.

Humans↗
PubMedDate not supplied

[Magnesium (Mg2+) cofactor in a triplet state reduces the proton of a coordinated water molecule to the hydrogen atom and pushes it out of the complex at a high speed].

Quantum chemistry methods [RHF/UHF + MP4(FULL), DFT:B3LYP] with the 6-311+ +G**(p,d) basis set were used to elucidate the properties of six coordinated Mg2+ complexes with water, glutamic acid and ATP/GTP in singlet (S) and triplet (T) states. In the triplet state, the magnesium complex concentrates its spin density on a coordinated water molecule (inner or outer coordination shell). Within the molecule, a redox reaction occurs, and one of the hydrogen atoms is pushed out of the complex at a speed of approximately 125 m/s. In water solution, the energy of the triplet state is higher than that of the singlet state. In a mixed environment composed of water, amino acids and ATP/GTR, the energy of the magnesium complex in the triplet state is lower than that in the singlet state by 1.5-2.0 kcal/mol. A little difference in T and S states allows the Mg(2+)-ATP/GTP complex to switch easily between two reaction mechanisms.

Adenosine Triphosphate↗
PubMed2002

Use of the lambda sign in fetal reduction of dizygotic triplets after intracytoplasmic sperm injection.

With the increased use of artificial reproductive technologies, there are ever greater numbers of multifetal pregnancies. The increased incidences of monozygotic twins and triplet gestations can be attributed to several factors. It is important to differentiate the chorionicity in the management of multifetal pregnancies because monochorionic gestations lead to an increased risk of prematurity, twin-to-twin transfusion, morbidity, and mortality. In a dizygotic triplet pregnancy, increased risks of obstetric complications result from the monozygotic twins, such as twin-to-twin transfusion, as well as from the presence of triplets. Fetal reduction can lower these risks. During the first trimester, a "lambda sign" on ultrasound can differentiate between monozygotic twins and a separate fetus. In this paper, we present selective fetal reduction of 1 of the monozygotic twins in order to reduce the risks resulting from either monozygotic twins or from triplets. By sacrificing 1 monozygotic twin, we believe the quality of life of the remaining babies in this case were improved.

Adult↗
PubMedDate not supplied

Excited complexes in oxidation-reduction photoreactions of pigments. I. Spectral detection of triplet state exciplex in the chlorophyll oxidation reaction.

Photooxidation of chlorophyll "a" with p-benzoquinone in toluene and dioxane is studied by the method of flash photolysis. It is shown that in nonpolar medium the triplet exiplex is the product of this reaction. The experiments on competitive quenching of chlorophyll triplet state with naphthacene prove the diffusion mechanism of exiplex formation. The spectrum of triplet-triplet absorption of the exiplex is presented and the rate constant of intercombination degradation equalling 1.103 sec(-1) is measured. Possible structure of the exiplex is discussed.

Chlorophyll↗
PubMedDate not supplied

[Coherent singlet-triplet transitions at the initial step of tubulin assembly into microtubules].

Quantum chemistry calculations [DFT-B3LYP QM/MM method, 6-31G** basis set, + ab initio molecular dynamics] were used to study the action of Mg2+ on tubulin properties. It was shown that the hydration of the guanosine triphosphate-tubulin forms a protein zone structure, which includes a electron-occupied zone and a conductivity zone. The binding of Mg2+ to guanosine triphosphate-tubulin results in the unpairing of electrons in the occupied zone (triplet state formation) followed by their transition to the conductivity zone in which the inversion of spin occurs (singlet state formation). The formation of triplet state is the initial step in the subsequent protein dynamics in the picosecond range of time. The dynamics shows up as a coherent oscillating transition of tubulin between the triplet and singlet states, which is evidence of a simultaneous adjustment between nuclear and electron configurations of the protein (ab initio molecular dynamics calculations). The barrier between the triplet and singlet states does not exceed 0.60 kcal x mol(-1). The barrier overcome is considered as electron tunneling through the Fermi surface, which separates the occupied and conductivity zones. Zone formation occurs in the presence of the shell of biological water surrounding the protein.

Microtubules↗
PubMed1990

Effects induced in neutrophils by a precursor of triplet acetone.

The addition of a precursor of the enol form of isobutanal to neutrophils results in formation of triplet acetone, as attested to by emission from appropriate acceptors and cell damage (Nascimento et al., 1986 Biochim. Biophys. Acta 888, 337-342). The present study confirms the formation of triplet acetone by detection of the direct emission (lambda max 430 nm) and differentiates between effects produced by triplet acetone and by the enol substrate itself. Thus, triplet acetone: (1) enhances the release of ribonucleic acid; (2) promotes lipid peroxidation (N3(-)-inhibitable formation of thiobarbituric acid reactive products and concomitant light emission peaking at 480-500 nm); (3) increases myeloperoxidase activity, presumable as a result of damage and consequent increased exposure of the enzyme. On the other hand, the enol greatly enhances the release of protein(s) into the medium. These results confirm the utility of the neutrophil as a model system for the study of chemiexcitation processes induced at the cellular level. They also provide the first demonstration that an excited species formed at the cellular level may induce release of nucleic acids, thus reflecting the occurrence of deleterious processes in situ.

1-Propanol↗
PubMedDate not supplied

[The use of triplet-sensitized photochromism phenomenon for the study of dynamic interaction of membrane proteins].

Possibility of registration of protein interactions in the membranes was demonstrated. The membrane preparation of Na+, K+ ATPase was used in the investigations. The Na+, K+ ATPase was bound with 4-acetoamido-4'-isothiocyanatostilbene-2,2' disullfonic acid (SITS) and erythrosinisothiocyanate (ERITC). The label/Na+,K+ATPase (M/M) ratio was equal to 1:1 for SITS and changed from 1:1 to 1:5 for ERITC. The cis-trans isomerization of SITS was initiated by triplet-triplet energy transfer from light excited ERITC to SITS. The kinetics of isomerization was recorded by the SITS fluorescence measurements. The rate constant of triplet-triplet energy transfer (kT) from ERITC to cis isomer of SITS, (3 divided by 7) X 10(3) M-1 s-1 was determined at 25 degrees C. The kT value of the energy transfer between loose molecules of erythrosine and SITS in buffer solution equaled to 7 X 10(7) M-1 s-1. This drop of kT in the membrane at 10(4) reflected the decrease in the frequency of label collisions caused by the increase in the media viscosity and steric hindrances.

Animals↗
PubMed1987

Translation initiation at an ACG triplet in mammalian cells.

The initiator AUC of the mouse dihydrofolate reductase gene (dhfr) was converted to ACG by site-directed mutagenesis and assayed for expression in cultured monkey cells using an SV40 recombinant called SVGT5dhfr26m2. Synthesis of apparently full-length dihydrofolate reductase (DHFR) protein was significantly reduced compared to wild-type, but not entirely abolished, suggesting that the ACG triplet was being utilized for translation initiation. In addition, a truncated form of DHFR was produced, apparently by initiation at the next in-frame AUG downstream. This result was confirmed in vitro. Transcripts of the dhfr sequence were produced by SP6 RNA polymerase in the presence of m7GpppG and translated in vitro using reticulocyte lysates and wheat germ extracts. The results paralleled those observed in vivo. Synthesis of full-length DHFR was reduced, but not eliminated, and a new species was produced by initiation at an internal site. Amino acid sequence analysis of the products of in vitro translation demonstrated that translation does indeed initiate at the ACG triplet and that it initiates with methionine. Additional mutations were introduced which altered the sequence context of the ACG triplet. Mutation of the translation initiation consensus sequence by substitution of the A residue at position -3, or of the G at +4 resulted in a significant decrease in initiation at the ACG and an increase in the level of the internal initiation product. Thus, translation initiation at a non-AUG triplet depends on a favorable sequence context.

Amino Acid Sequence↗
PubMed1996

Zygosity and placental anatomy in 15 consecutive sets of spontaneously conceived triplets.

Most triplets are trizygotic because they result from assisted reproduction. Prognosis is generally good. We analyzed 15 sets of triplets who were conceived spontaneously. Six sets were monozygotic, 7 were dizygotic, and only 2 sets were trizygotic. Considered as 45 twin pairs, 25 pairs (56%) were monozygotic. Twenty percent of these twins died as a result of twin-twin transfusion. Spontaneously conceived triplets have high risks compared with those resulting from assisted reproduction. These risks result from a high proportion of monozygotic embryos, many of whom have monochorionic placentas with vascular anastomoses, causing twin-to-twin transfusion.

Birth Weight↗
PubMedDate not supplied

Sonographic diagnosis of triplet tubal pregnancy after in vitro fertilization and embryo transfer.

Ectopic pregnancy (EP) after in vitro fertilization and embryo transfer (IVF/ET) is not rare, but triplet tubal pregnancy after IVF/ET is very rare. We describe a patient with hydrosalpinx in whom a triplet tubal pregnancy occurred on the same side as the hydrosalpinx. Close hormonal and sonographic monitoring of pregnancies achieved through IVF is recommended to ensure the early diagnosis of EP and to avert complications. A triplet tubal EP was considered highly probable after 3 gestational sacs were observed outside the uterus during sonography performed at 6 weeks' gestation. Therapeutic laparoscopy was then performed because methotrexate treatment failed. Appropriate management strategies are discussed.

Adult↗
PubMed1994

Prediction of neonatal crown-heel length in normal singletons, twins, and triplets using individualized growth assessment.

In groups of normally growing singletons (20), twins (20), and triplets (13), predicted femur diaphysis length (FDL) values at birth were obtained using Rossavik growth models specified from second-trimester ultrasound studies of fetal growth. Six previously published functions were utilized to obtain predicted crown-heel length (CHL) values from predicted FDL values. These values were compared to the actual CHL values and the percent differences calculated. Based on their systematic (mean percent difference) and random (standard deviation of percent difference) prediction errors, the functions of Vintzileos (singletons), Hadlock (twins), and Brown (triplets) were found to give optimal results (no systematic error; random error: +/- 6%). Using predicted CHL values obtained with these optimal functions, growth potential realization index values for CHL (GPRICHL) were determined for singletons, twins, and triplets. In all three groups, the mean GPRICHL value was 100% with a range of approximately 95% to 105%. These results indicate that the CHL can be predicted from second-trimester growth patterns and evaluated using individualized growth assessment methods.

Embryonic and Fetal Development↗
PubMed1993

Homosexual orientation in twins: a report on 61 pairs and three triplet sets.

Twin pairs in which at least one twin is homosexual were solicited through announcements in the gay press and personal referrals from 1980 to the present. An 18-page questionnaire on the "sexuality of twins" was filled out by one or both twins. Thirty-eight pairs of monozygotic twins (34 male pairs and 4 female pairs) were found to have a concordance rate of 65.8% for homosexual orientation. Twenty-three pairs of dizygotic twins were found to have a concordance rate of 30.4% for homosexual orientation. In addition, three sets of triplets were obtained. Two sets contained a pair of monozygotic twins concordant for sexual orientation with the third triplet dizygotic and discordant for homosexual orientation. A third triplet set was monozygotic with all three concordant for homosexual orientation. These findings are interpreted as supporting the argument for a biological basis in sexual orientation.

Adult↗
PubMed2004

Cerebral palsy in triplet pregnancies with and without iatrogenic reduction.

UNLABELLED: Iatrogenic fetal reduction is undertaken to try and improve the outcome of multiple pregnancies by reducing the rate of severe preterm delivery. In twin pregnancies, however, spontaneous death of one of the fetuses is associated with increased risk of cerebral palsy (CP) in the survivor. The aim of this study was to determine whether iatrogenic fetal reduction might also increase the prevalence of CP. The database of a tertiary fetal medicine unit was interrogated to identify women with trichorionic triplet pregnancies who had either given birth to three live infants or two live infants following selective fetal reduction. A questionnaire was sent to the women's general practitioners asking them to report whether any of the children had CP. The results of the questionnaire revealed that the CP prevalence (13.8 per 1000) of 72 children from trichorionic triplet pregnancies reduced to twins by selective termination was similar to that of 111 children from trichorionic triplet pregnancies with no loss (18 per 1000), but the pregnancies with selective termination delivered at a later gestation (P = 0.004). CONCLUSION: a lower cerebral palsy rate might have been expected in the pregnancies with selective termination given that they were delivered at a later gestational age; these data, therefore, emphasise the importance of further investigating the impact of selective reduction on the prevalence of cerebral palsy.

Cerebral Palsy↗
PubMed2005

Diamniotic conjoined fetuses in a triplet pregnancy: an insight into embryonic topology.

We present a case of triplets, 2 of whom were monochorionic diamniotic conjoined fetuses, and the other triplet was in a separate chorion. The pregnancy followed in vitro fertilization with 2 embryo transfers and the conjoined fetuses developed from a single embryo. An early ultrasound showed 2 embryos attached to 1 yolk sac. Further monitoring of the pregnancy showed these 2 triplets to be diamniotic with a short umbilical cord/body stalk anomaly. After fetal loss a postmortem examination demonstrated that these fetuses were conjoined with a body stalk anomaly/short umbilical cord syndrome with fusion of the coelomic cavities and small bowel (minimally united/conjoined twins). There were dividing amniotic membranes. This case demonstrates the development of an unusual type of conjoined twin with characteristic features. Conjoined fetuses with this pattern have fused small bowel and cloacal anomalies and often diamniotic placentation, when this is recorded. Various terms including minimally united/conjoined omphalopagus/ischiopagus have been used for this characteristic pattern, but this pattern may warrant a specific term. "Diamniotic vitellopagus" may best reflect the pathogenesis of this pattern.

Abnormalities, Multiple↗
PubMed1988

The Northwestern University triplet study. IV. Biochemical parameters.

Umbilical arterial and venous blood gas indices of 11 triplet pregnancies were reviewed. Ten sets of triplets were delivered by cesarean section and one set was delivered vaginally. Mean 1-minute Apgar scores were significantly lower in the group of infants delivered third than in either of the other birth order groups. There were no statistically significant differences when the mean umbilical arterial or venous pH, PCO2, and base deficit were compared among any one triplet and the other two. Similarly, no significant differences were found when these parameters were compared by birth order in relation to mean 5-minute Apgar scores, mean birth weights, and mean gestational ages at delivery. Birth order did not appear to significantly influence acid-base status, although it may become significant with an increasing time in utero after delivery of the firstborn infant. Further study is necessary to investigate whether there is a critical interval of delivery whereby the infants remaining in utero become acidotic.

Apgar Score↗
PubMed1989

The improving outcome of triplet pregnancies.

During the period 1975 to 1988, 78 triplet pregnancies that reached a gestational age greater than or equal to 20 weeks were treated in our department--a prevalence of 1/849 deliveries. A total of 69 (88%) of the pregnancies occurred after treatment with ovulation-induction agents. The most common complication of pregnancy was premature contractions. Elective cervical cerclage neither prolonged gestation nor decreased fetal loss. The mean gestational age at delivery was 33.2 weeks + 3.8 weeks and 86% of the patients were delivered of premature infants. The perinatal and neonatal mortality rates were 93/1000 and 51/1000, respectively. Our results show a higher proportion of low Apgar scores and respiratory disorders in the third vaginally delivered infants. Follow-up of very low birth weight infants revealed four infants (10.5%) with severe neurologic handicaps. Results of this study suggest that cesarean section is the preferred mode of delivery in triplet pregnancies. Maternal, fetal, and neonatal risks of triplet gestations are relatively low and compare favorably with recent reports on twin pregnancies.

Adult↗
PubMed1995

Costs of triplet pregnancy.

OBJECTIVE: Our purpose was to describe the total costs involved in the delivery, prenatal, and neonatal care for triplet pregnancies. STUDY DESIGN: Twenty triplet pregnancies were born at our institution over the 1-year period between July 1, 1992, and June 30, 1993. Total charges for prenatal care, physician fees, antepartum admissions, delivery, postpartum inpatient and outpatient care, and neonatal inpatient and outpatient care were extracted from the hospital billing computers. RESULTS: Our 20 triplet pregnancies were delivered of 54 live born infants at an average gestation of 30.2 weeks. Mothers averaged 16.7 inpatient hospital days. Total cost of prenatal care, outpatient laboratories and ultrasonography, delivery, and maternal inpatient care averaged $27,491. Neonates averaged 13.7 hospital days. Total neonatal costs for the inpatient stay and short term-postpartum (< 6 week) outpatient period was $36,856 per family. Total average cost per family was $64,347. CONCLUSION: Combined maternal and neonatal costs per individual baby delivered was approximately $21,000. Although expensive, this cost is far from prohibitive, even in times of close attention to health care expenditures.

Boston↗