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PubMed2002

Vascularization in the primate visual cortex during development.

We studied the relationship between vascularization and neuronal activity in the visual cortex during postnatal development in the primate. Analyses were focused on layer IVC that displays a sequential pattern of maturation for the magno- and parvocellular systems in separate sublayers, respectively IVC alpha and IVC beta. Cytochrome oxidase and endogenous alkaline phosphatase histochemistry was used to analyse, on the same sections, the laminar patterns of cortical activity and vessel density in the primary visual cortex of the marmoset (Callithrix jacchus). Experiments were carried out in five young and two adult animals. We showed that the temporal pattern of angiogenesis differs in layer IVC alpha and IVC beta. During the first postnatal month, vessel density is higher in IVC alpha than in IVC beta and runs parallel to cytochrome oxidase intensity. In 2-month-old animals, both vessel densities and cytochrome oxidase activity are similar in IVC alpha and IVC beta. In adults, the vessel densities in IVC alpha and IVC beta are the reverse of those observed during the first postnatal month. Vessel diameter does not account for this evolution in vascular patterns. In the discussion, we suggest that such a developmental time-course of angiogenesis might be linked to the synaptogenesis requirements that proceed differently for the magno- and parvocellular systems in the primate striate cortex.

Alkaline Phosphatase↗

PubMed1993

Maintenance of Chloroplast Components during Chromoplast Differentiation in the Tomato Mutant Green Flesh.

During ripening of tomato (Lycopersicon esculentum) fruit, chloroplasts develop into chromoplasts. The chloroplast-chromoplast transition is marked by the accumulation of carotenoids and the disappearance of chlorophyll, the degradation of the highly structured thylakoid membrane system, and a reduction in the levels of proteins and mRNAs associated with photosynthesis. In the tomato mutant green flesh (gf), detectable amounts of chlorophyll remain in the ripe, mutant fruit, giving rise to a rusty red fruit color and suggesting that at least chlorophyll degradation is defective in the mutant. We show here that the ultrastructure of the plastids in the ripe gf fruit maintained significant amouonts of the chloroplast thylakoid grana along with structures characteristic of tomato chromoplasts. The maintenance of chloroplast structure in the gf ripe fruit was paralleled on the molecular level by the retention of plastid photosynthetic components that normally decline significantly in ripening tomato fruits. These included the light-harvesting chlorophyll a/b-binding proteins of photosystem II, the second electron accepting plastoquinone of photosystem II binding protein, the large and small subunits of ribulose bisphosphate carboxylase/oxygenase, the 33-kD oxygen evolution protein, and cytochrome b559. Similarly, photosynthetic transcripts, cab, psbA, rbcL, rbcS, and psbE mRNAs, also accumulated to higher levels in ripening gf fruit than wild type. It is interesting that the levels of some of these transcripts, especially cab mRNA, were noticeably higher in the mature gf green fruit than in the corresponding wild-type fruit. This suggests that the onset of the effect from the gf mutation might be earlier than fruit ripening. We also observed that when chloroplast formation was blocked during the development and ripening of gf fruit, these mutant fruits were bright red and their chromoplasts were indistinguishable from those found in wild-type ripe fruits grown and ripened either in the dark or in the light. These results suggest that the lesion in gf may alleviate conditions associated with chloroplast deterioration during the chloroplast-chromoplast transition in tomato ripening but has no direct effect on chromoplast differentiation per se. The ultrastructure of gf provides unequivocal evidence that, in ripening tomato, chromoplasts indeed differentiate from preexisting chloroplasts; on the other hand, chromoplast differentiation in the dark-matured and -ripened tomato fruits indicates that chromoplast development can be a process entirely independent of the chloroplasts.

Journal Article↗

PubMedDate not supplied

Structure-function relationship of bromelain isoinhibitors from pineapple stem.

Bromelain isoinhibitors from pineapple stem (BIs) are unique double-chain inhibitors and inhibit the cysteine proteinase bromelain competitively. The three-dimensional structure was shown to be composed of two distinct domains, each of which is formed by a three-stranded anti-parallel beta-sheet. Unexpectedly, BIs were found to share similar folding and disulfide-bond connectivities not with the cystatin superfamily, but with Bowman-Birk trypsin/chymotrypsin inhibitor (BBI). The structural similarity between them suggests that BIs and BBI have evolved from a common ancestor and differentiated in function during the course of molecular evolution.

Amino Acid Sequence↗

PubMed2026

mRNA therapy: A novel approach for retinal neurodegenerative diseases.

Retinal neurodegeneration remains a major cause of irreversible vision loss, yet current therapeutic options are limited in effectiveness. Although gene therapies have shown clinical potential, the overexpression platforms they rely on, such as adeno-associated virus DNA, are constrained by safety concerns, limited efficacy, and cargo size restrictions. In contrast, mRNA therapy has gained recognition as a compelling alternative, enabling rapid and efficient protein expression without the risk of genomic integration. This review synthesizes recent advances in mRNA engineering, delivery systems, and administration routes for retinal applications, and highlight strategies to enhance targeting, penetration, and controlled release through interdisciplinary collaboration between ophthalmology and bioengineering. In recent years, engineered mRNA formats, including chemically modified linear, circular, and self-amplifying RNA, can achieve higher translation efficiency within a tunable expression window. The transient nature and relatively low immunogenicity of in vitro transcribed mRNA support repeat dosing without insertional mutagenesis. Advances in nanocarriers, particularly lipid nanoparticles, have enabled preferential delivery to retinal neurons, Müller glia, and pigment epithelium via intraocular administration, while improving mRNA stability and transfection efficiency. In preclinical studies, mRNA has been widely used to deliver gene-editing tools, transcription factors, and supplementary functional proteins. In disease models such as optic nerve crush and laser-induced choroidal neovascularization, mRNA-based therapies enhance neuroprotection and suppress pathological angiogenesis in the injured retina, with favorable ocular safety profiles. However, it remains largely unexplored how the intrinsic advantages of mRNA therapy can be leveraged to develop tailored strategies for complex retinal disorders. Consistent with this gap, mRNA platforms have not yet been widely incorporated into retinal research or clinical practice. In parallel, clinical translation also lags: despite encouraging outcomes of lipid nanoparticle-mRNA formulations in preclinical models, no candidates have progressed into retinal clinical trials. This review draws on the complex pathology and therapeutic logic of retinal neurodegeneration. It proposes that mRNA therapy enables multitarget, repeatable, stage-specific interventions that align with the dynamic evolution of diseases and the requirements of combination therapy in retinal diseases. It may be used to support neuroprotection, axon regeneration, and neurovascular regulation. By integrating data across experimental models and modalities, this review outlines representative cases and experimental paradigms to guide rational trial design and carrier selection. Taken together, technical progress and evolving application strategies position mRNA therapy as a compelling therapeutic avenue for retinal neurodegeneration.

administration↗

PubMed1987

The conformation of T4 bacteriophage dihydrofolate reductase from circular dichroism.

The secondary and tertiary structure of T4 bacteriophage dihydrofolate reductase is investigated by vacuum ultraviolet circular dichroism (CD) spectroscopy and probability analysis of the primary amino acid sequence. The far ultraviolet CD spectrum of the enzyme in the range of 260-178 nm is analyzed by the generalized inverse and variable selection methods developed by our laboratory. Variable selection yields an average content of 26% alpha-helix, 21% antiparallel beta-sheet, 10% parallel beta-sheet, 20% beta-turns, and 32% "other" structures within the T4 protein. The characteristic peaks of the CD spectrum indicate that the enzyme has a lot of antiparallel beta-sheet, which is typical of the alpha + beta tertiary class of globular proteins. The secondary structure of the protein is also analyzed by using four statistical methods on the amino acid sequence. Although the secondary structures predicted by each individual statistical method vary to a considerable extent, the fractions of each structure jointly predicted by a majority of the methods are in excellent agreement with our CD analysis. The alternating arrangement for some segments of alpha-helix and beta-sheet predicted from primary structure to be within the enzyme is characteristic of proteins containing parallel beta-sheet. This supports our conclusion that the protein contains both parallel and antiparallel beta-sheet structures, but finding both types of beta-sheet also means that the protein may have the variation on alpha/beta tertiary structure recently found in EcoRI endonuclease and thymidylate synthase. These observations, in conjunction with other physical properties of the T4 reductase, suggest that the enzyme perhaps shares an evolution in common with the dihydrofolate reductases derived from type I R-plasmids rather than with the host-cell protein.

Circular Dichroism↗

PubMed1994

A pilot study of subcutaneous recombinant hirudin (HBW 023) in the treatment of deep vein thrombosis.

BACKGROUND: Recombinant hirudin, a pure, specific antithrombin could be more effective than heparin in the treatment of deep vein thrombosis, but its short half-life requires constant intravenous infusion, whereas subcutaneous administration of recombinant hirudin can ensure stable and prolonged plasma levels. The aim of our study was to assess the pharmacokinetics, the results on the coagulation variables, and the safety of a recombinant hirudin (HBW 023) administered subcutaneously in patients suffering from deep vein thrombosis. METHODS: Recombinant hirudin (HBW 023) was administered subcutaneously to 10 patients with recent deep vein thrombosis, at a dose of 0.75 mg/kg of body weight twice daily for 5 days, after which standard heparin and acenocoumarol were introduced. Bilateral lower limb venography, and pulmonary angiography, and/or ventilation-perfusion lung scan were carried out on day 1 prior to recombinant hirudin injection and repeated on day 5. aPTT and recombinant hirudin plasma levels were serially assessed after the 1st and the 10th injections. Prothrombin fragments 1 + 2, thrombin-antithrombin III complexes, fibrin degradation products were collected on days 1 and 5. RESULTS: Clinical evolution was uneventful in all but one patient who had a probable recurrence of pulmonary embolism on day 4. No hemorrhagic complication, no untoward biological event was observed. On days 5, Marder score was unchanged or had decreased. Plasma levels of recombinant hirudin peaked in between 3 and 4 h following the injection. aPTT values paralleled, and were significantly correlated with plasma levels of recombinant hirudin on day 1 as well on day 5 (r = 0.903, r = 0.948 respectively). Fragment 1 + 2, and thrombin antithrombin complexes non-significantly decreased from day 1 to day 5. CONCLUSIONS: Subcutaneous administration of recombinant hirudin ensures prolonged stable plasma levels of recombinant hirudin which results in efficient anticoagulation. A dose-ranging study conducted with subcutaneous recombinant hirudin in comparison to conventional heparin therapy may answer the question as to efficacy.

Adolescent↗

PubMed1979

[Evolution of plasma concentration of gonadotropins and corticosterone during the growth of the male rat (author's transl)].

Plasma LH, FSH and corticosterone were determined between the 15th and 90th day of life, in normal male Rat. Plasma gonadotropins and corticosterone at basal conditions or after psychic aggression increased from the 15th to the 40th or 45th day of life; then all hormones decreased to adult age. The development of plasma gonadotropins and corticosterone are carried out in a parallel manner during the period studied. It was thought that perhaps the elevation of gonadotropins secretion might have stimulated the adrenals.

Aging↗

PubMed2003

Evolution of low-copy number and major satellite DNA sequences coexisting in two Pimelia species-groups (Coleoptera).

Satellite DNA sequence evolution has been studied in several insect species from the genus Pimelia (Tenebrionidae, Coleoptera). Low-copy number homologs of the previously characterized major satellite DNA from P. monticola (PMON) have been cloned and sequenced from six congeneric species belonging to two species groups: Ibero-Balearic and Moroccan. Sequence analysis of a sample of low-copy number repeats revealed two subfamilies, differing on average 17.5% due to randomly spread single point mutations. Each subfamily is specific for a group of taxa in congruence with their biogeography. Within each group, there is no significant species-specific clustering of the sequences. These results suggest that the two satellite subfamilies arose after the split of an ancestral lineage into the North African and Ibero-Balearic Pimelia species-groups, but before their subsequent radiation. Rate heterogeneity tests suggest that PMON sequences have evolved faster in the lineage leading to the Moroccan group. Comparison of sequence divergences between minor PMON and the previously characterized major PIM357 satellite obtained from the same taxa, points to similar evolutionary dynamics. Both sequences are evolving in parallel accumulating mutations in a gradual manner irrespectively of significant differences in abundance. These data show that copy number of the sequence families does not necessarily affect the sequence change dynamics of satellite repeats.

Animals↗

PubMed2003

Conserved structural motifs in intracellular trafficking pathways: structure of the gammaCOP appendage domain.

The formation of coated vesicles is a fundamental step in many intracellular trafficking pathways. COPI and clathrin represent two important and distinct sets of vesicle coating machinery, involved primarily in mediating intra-Golgi and endocytic transport, respectively. Here we identify an important functional region at the carboxyl terminus of the gamma subunit of the COPI complex (gammaCOP) and describe the X-ray crystal structure of this domain at 2.3 A resolution. This domain of gammaCOP exhibits unexpected structural similarity to the carboxyl-terminal appendage domains of the alpha and beta subunits of the AP2 adaptor proteins, integral components of clathrin-coated vesicles. The remarkable structural conservation exhibited by the gammaCOP appendage domain, coupled with functional data and primary sequence analysis, supports a model of COPI function with significant structural and mechanistic parallels to vesicular transport by the clathrin/AP2 system.

Adaptor Protein Complex 2↗

PubMed2000

Sexual isolation between Drosophila melanogaster, D. simulans and D. mauritiana: sex and species specific discrimination.

The sexual isolation among the related species Drosophila melanogaster, D. simulans and D. mauritiana is asymmetrical. While D. mauritiana males mate well with both D. melanogaster and D. simulans females, females of D. mauritiana discriminate strongly against males of these two species. Similarly, D. simulans males mate with D. melanogaster females but the reciprocal cross is difficult. Interspecific crosses between several populations of the three species were performed to determine if (i) males and females of the same species share a common sexual isolation genetic system, and (ii) males (or females) use the same genetic system to discriminate against females (or males) of the other two species. Results indicate that although differences in male and female isolation depend on the populations tested, the isolation behaviour between a pair of species is highly correlated despite the variations. However, the rank order of the isolation level along the populations was not correlated in both sexes, which suggests that different genes act in male and female sexual isolation. Neither for males nor for females, the isolation behaviour of one species was paralleled in the other two species, which indicates that the genetic systems involved in this trait are species-pair specific. The implications of these results are discussed.

Animals↗

PubMed1995

Evolutionary conservation of human TATA-binding-polypeptide-associated factors TAFII31 and TAFII80 and interactions of TAFII80 with other TAFs and with general transcription factors.

Human transcription initiation factor TFIID is composed of the TATA-binding polypeptide (TBP) and at least 13 TBP-associated factors (TAFs) that collectively or individually are involved in activator-dependent transcription. To investigate protein-protein interactions involved in TFIID assembly and in TAF-mediated activator functions, we have cloned and expressed cDNAs encoding human TAFII80 and TAFII31. Coimmunoprecipitation assays showed that TAFII80 interacted with TAFII250, TAFII31, TAFII20, and TBP, but not with TAFII55. Similar assays showed that TAFII80 interacted with TFIIE alpha and with TFIIF alpha (RAP74) but not with TFIIB, TFIIE beta, or TFIIF beta (RAP30). Further studies with TAFII80 mutations revealed three distinct interaction domains which fall within regions conserved in human TAFII80, Drosophila TAFII60, and yeast TAFII60. The N terminus of TAFII80 (residues 1-100) interacts with both TAFII31 and TAFII20, while two C-terminal regions are involved, respectively, in interactions with TAFII250 and TFIIF alpha (RAP74) (residues 203-276) and with TBP and TFIIE alpha (residues 377-505). The interactions between TAFII80 and general factors TFIIE alpha and TFIIF alpha (RAP74) could be important for recruitment of GTFs during activator-dependent transcription. Because TAFs 80, 31, and 20 show sequence similarities to histones H4, H3, and H2B, as well as some parallel interactions, this subset of TAFs may form a related core structure within TFIID.

Amino Acid Sequence↗

PubMed1986

The major histocompatibility complex of tassel-eared squirrels. II. Genetic diversity associated with Abert squirrels.

The extent of polymorphism and the rate of divergence of class I and class II sequences mapping to the mammalian major histocompatibility complex (MHC) have been the subject of experimentation and speculation. To provide further insight into the evolution of the MHC we have initiated the analysis of two geographically isolated subspecies of tassel-eared squirrels. In the preceding communication we described the number and polymorphism of TSLA class I and class II sequences in Kaibab squirrels (S. aberti kaibabensis), which live north of the Grand Canyon. In this report we present a parallel analysis of Abert squirrels (S. aberti aberti), which live south of the Grand Canyon in northern Arizona. Genomic DNA from 12 Abert squirrels was digested with restriction enzymes, electrophoresed, blotted, and hybridized with DR alpha, DR beta, DQ alpha, DQ beta, and HLA-B7 probes. The results of these hybridizations were remarkably similar to those obtained in Kaibab squirrels. The majority of class I and class II bands were identical in size and number, suggesting that Abert and Kaibab squirrels have not significantly diverged in the TSLA complex despite their geographical separation. Relative polymorphism of class II sequences was similar to that observed with Kaibab squirrels: beta sequences exhibited higher polymorphism than alpha sequences. As in Kaibab squirrels, a number of alpha and beta sequences were apparently carried on the same fragments. In comparison to class II beta sequences, there was limited polymorphism in class I sequences, although a diverse number of class I genotypes were observed. Attempts to identify segregating TSLA haplotypes were futile in that the only families of sequences with concordant distributions were DQ alpha and DQ beta. These observations and those obtained with Kaibab squirrels suggest that the present-day TSLA haplotypes of both subspecies are derived from a limited number of common, progenitor haplotypes through repeated intra-TSLA recombination.

Animals↗

PubMed1991

Drosophila fat body protein P6 and alcohol dehydrogenase are derived from a common ancestral protein.

Drosophila melanogaster alcohol dehydrogenase is an example of convergent evolution: it is not related to the ADHs of other organisms, but to short-chain dehydrogenases, which until now have been found only in bacteria and in mammalian steroid hormone metabolism. We present evidence that the Drosophila ADH is phylogenetically more closely related to P6, another highly expressed protein from the fat body of Drosophila, than it is to the short-chain dehydrogenases. The polypeptide sequence of P6 was inferred from DNA sequence analysis. Both ADH and P6 polypeptides have retained a high structural similarity with respect to the Chou-Fasman prediction of secondary structure and hydropathy. P6 is also homologous to the 25-kd protein from the fat body of Sarcophaga peregrina, whose sequence we have reexamined. The evolution of the P6-ADH family of proteins is characterized by a dramatic increase in the methionine content of P6. Methionine accounts for 20% of P6 amino acids. This is in contrast with the absence of this amino acid in mature ADH. There is evidence that P6 and the 25-kd protein have undergone a parallel and independent enrichment in methionine. When corrected for this, the rate of amino acid replacement shows that the P6-25-kd lineage diverged from insect ADH shortly before the divergence of the ADH gene (Adh) from its 3'-duplication (Adh-dup).

Alcohol Dehydrogenase↗

PubMed2003

Laboratory models of the thermal evolution of the mantle during rollback subduction.

The subduction of oceanic lithosphere plays a key role in plate tectonics, the thermal evolution of the mantle and recycling processes between Earth's interior and surface. Information on mantle flow, thermal conditions and chemical transport in subduction zones come from the geochemistry of arc volcanoes, seismic images and geodynamic models. The majority of this work considers subduction as a two-dimensional process, assuming limited variability in the direction parallel to the trench. In contrast, observationally based models increasingly appeal to three-dimensional flow associated with trench migration and the sinking of oceanic plates with a translational component of motion (rollback). Here we report results from laboratory experiments that reveal fundamental differences in three-dimensional mantle circulation and temperature structure in response to subduction with and without a rollback component. Without rollback motion, flow in the mantle wedge is sluggish, there is no mass flux around the plate and plate edges heat up faster than plate centres. In contrast, during rollback subduction flow is driven around and beneath the sinking plate, velocities increase within the mantle wedge and are focused towards the centre of the plate, and the surface of the plate heats more along the centreline.

Journal Article↗

PubMed1999

Integrating knowledge resources at the point of care: opportunities for librarians.

Health sciences librarians at the University of Washington (UW) are partners in the evolution of Internet-based clinical information systems for two medical centers, University of Washington Medical Center and Harborview Medical Center, as well as the UW Primary Care Network clinics. Librarians lead information resource and systems development projects and play a variety of roles including facilitator, publisher, integrator, and educator. These efforts have been coordinated with parallel development efforts by the Integrated Advanced Information Management Systems (IAIMS) clinical informatics group in developing electronic medical record systems and clinical decision support tools. The outcome is MINDscape, a very heavily used Web view of the patient medical record with tightly integrated knowledge resources as well as numerous Web-accessible information resources and tools. The goal of this article is to provide a case study of librarian involvement in institutional information systems development at UW and to illustrate the variety of roles that librarians can assume in hospital settings.

Computer Systems↗

PubMed1991

[The treatment of chronic stable angina with isradipine. A cooperative Latin American study].

In order to study the efficacy and tolerance of isradipine, a new Ca++ antagonist for the treatment of stable chronic angina, a multicentric cooperative study was carried out in eight Latin American countries (Argentine, Chile, Colombia, Ecuador, Mexico, Peru, Uruguay and Venezuela), which included 169 patients (60% men and 40% women), average age 62.6 +/- 9.7. Patients with more than 4 biweekly anginal crisis were accepted, with one or more of the following inclusion criteria: coronariographic evidence of obstruction greater than 60% in one or more vessels, IAM history, positive scintigraphy and positive effort test. The trial was single-blind, with placebo during the admission phase (2 weeks) and active treatment for 12 weeks. isradipine was administered in increasing doses of 2.5, 5, and 7 mg thrice a day, according to the presence or absence of anginal crisis. It was observed that the average frequency of weekly pains decreased from 8.2 +/- 7 under placebo to 6.3 +/- 7.5 under isradipine at low doses, and to 2.0 +/- 2.0 (p less than 0.001) under maximum doses. TNT intake decreased parallel also in a significant way. At the end of the trial, 37% of patients had become asymptomatic, and angina had reduced to less than two crisis a week in 33%. A clear relation doses-effect was observed. There was no alteration in laboratory exams neither in ECG. Seven patients had complications derived from the evolutional course of disease (2 IAM, 5 unstable angina and one sudden death). Adverse events were relatively frequent and the majority derived from vasodilator effect (tibial oedema 37%, flushing 17%, headache 23%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

[Antimalaria fluorescent antibodies evolution in young children living in a stable malaria area (author's transl)].

The detection of malarial fluorescent antibodies have been performed in an Abidjan dispensary on 30 newborn babies with their mothers, 30 children 3 months old and 120 children from 6 to 24 months. This survey took place during the small rainy season and it demonstrates that: --synthesis of specific antibodies is significantly starting after the 3rd month; --the rise, after six months, of the malarial antibodies is parallel to the plasmodic index checked during the same period in the same area; --the rate of antibodies in 2 years old babies is almost the same that in adults; --living conditions in rural areas accelerate the synthesis of antibodies which, adversely, is slowed down by regular chemoprophylaxis; --Plasmodium berghei is a valuable antigen for mass survey; --Abidjan town is an hypoendemic zone of stable malaria in a mesoendemic area.

Antibody Formation↗

PubMed1987

Implementing the Omaha classification system in a public health agency.

Systemized nursing diagnosis based on standardized, coded terminology is in the early stages of evolution. The Waukesha Health Department has been a part of that evolutionary process. Introduction of the concept of nursing diagnosis led to the conclusion that for this agency a more systematic, community tested taxonomy was needed. The OCS was the system selected. The progress of the two systems, NANDA and OCS, appears to be evolving in parallel. No doubt, in the future one system will emerge as best for all fields of nursing. Meanwhile, the use of the OCS in practice settings serves the evolutionary process well by providing a foundation of trial and experience.

Humans↗

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