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PubMed2003

Recognizing and interpreting the fossils of early eukaryotes.

Using molecular sequence data, biologists can generate hypotheses of protistan phylogeny and divergence times. Fossils, however, provide our only direct constraints on the timing and environmental context of early eukaryotic diversification. For this reason, recognition of eukaryotic fossils in Proterozoic rocks is key to the integration of geological and comparative biological perspectives on protistan evolution. Microfossils preserved in shales of the ca. 1500 Ma Roper Group, northern Australia, display characters that ally them to the Eucarya, but, at present, attribution to any particular protistan clade is uncertain. Continuing research on wall ultrastructure and microchemistry promises new insights into the nature and systematic relationships of early eukaryotic fossils.

Animals↗
PubMed2000

Fourth-order algorithms for solving the multivariable Langevin equation and the Kramers equation.

We develop a fourth-order simulation algorithm for solving the stochastic Langevin equation. The method consists of identifying solvable operators in the Fokker-Planck equation, factorizing the evolution operator for small time steps to fourth order, and implementing the factorization process numerically. A key contribution of this paper is to show how certain double commutators in the factorization process can be simulated in practice. The method is general, applicable to the multivariable case, and systematic, with known procedures for doing fourth-order factorizations. The fourth-order convergence of the resulting algorithm allowed very large time steps to be used. In simulating the Brownian dynamics of 121 Yukawa particles in two dimensions, the converged result of a first-order algorithm can be obtained by using time steps 50 times as large. To further demonstrate the versatility of our method, we derive two new classes of fourth-order algorithms for solving the simpler Kramers equation without requiring the derivative of the force. The convergence of many fourth-order algorithms for solving this equation are compared.

Journal Article↗
PubMed1978

Effect of selective goitre resection on absent thyrotrophin response to thyrotrophin releasing hormone in idiopathic euthyroid goitres.

Absent thyrotrophin (TSH) response to thyrotrophin releasing hormone (TRH) was found in ten of fifty consecutive nodular goitrous patients who were clinically and biochemically euthyroid. These ten patients together with a reference group engaging fifty-eight healthy individuals matched for sex, age, and geographic region form the basis of the present study. Patients with autonomously functioning single adenomata were excluded from the investigation. In the patient group, values of serum thyroxine (T4), free T4-index, and serum TSH did not differ significantly from those recorded in the reference group, whereas serum triiodothyronine was found to be significantly higher in the patients, although within the normal range. After selective resection of the goitre, the TSH responsiveness to TRH recovered completely. Routine indices of thyroid function, however, demonstrated no major deviation from pre-operative levels. During a follow-up period of 1 year, no systematic alterations were recorded in TSH response to TRH nor in the thyroid function tests, indicating maintenance of euthyroidism with restored normality within the pituitary-thyroid axis. The present study lends support to the view that increasing functional autonomy apparently is a common trend in goitre evolution in a non-endemic area.

Adult↗
PubMedDate not supplied

Meta-analysis: apples and oranges, or fruitless.

Meta-analysis is an impressive tool for systematic synthesis of health care management and policy research findings. Used wisely, it can impose an appealing order on the chaos of a large body of evidence. Occasionally, it can even contribute to resolution of a clinical controversy. However, the technique is currently in a state of evolution. Until it is further refined and standardized, its consumers must be mindful of its limitations and use meta-analytic reviews with care.

Health Services Research↗
PubMed1992

[Nosology, genetics, neurobiology, and psychopharmacology of schizophrenia].

The development of psychiatric nosology is outlined, and five principles responsible for the organization of psychopathologic symptoms into psychiatric disorders are proposed. Within the frame of reference of the nosologic organizing principles, the evolution and dissolution of the unitary concept of schizophrenia are reviewed, and some of the findings in neurobiologic, genetic and psychopharmacologic validation studies are discussed. It is suggested that findings in family genetic studies and in clinical psychopharmacologic investigations are supportive of Leonhard's (1957) contention that systematic and unsystematic schizophrenia are two distinct populations.

Humans↗
PubMedDate not supplied

Evaluation of circulating immune complexes in cutaneous diseases associated with immune disorders.

Several skin diseases associated with immune disorders may be related to the formation of circulating immune complexes (CIC) and their skin deposition. Sera from 20 controls and 108 patients, including: 23 psoriasis, 10 lichen planus, 30 atopic eczemas, 32 cases of leprosy, 10 vasculitis and 3 pyoderma gangrenosum were evaluated for the presence of IgG-containing CIC by the microconsumption complement test (MCT). Additionally, the presence of IgE-containing CIC by means of a polyethylene glycol precipitation and radioimmunoassay technique was evaluated in 10 patients with atopic eczema. It was found that 56.5% of psoriatic patients show moderate CIC concentrations, as well as 34% of leprosy patients, with increased levels when bacillus were detected in skin lesions, and in 90% of leukocytoclastic vasculitis. A close relationship between CIC levels and the clinical evolution of skin lesions was demonstrated in patients with pyoderma gangrenosum and lichen planus. IgG-CIC were detected in 33% and IgE-CIC in 30% of patients with atopic eczema, with the presence of both types of CIC in 2 out of 3 cases. The systematic research on CIC presence in some selected skin diseases shows that immune complexes take part, with different degrees of relevance, in the pathogenesis of all the entities.

Adolescent↗
PubMed1979

[Acute granulomatous appendicitis. (Contribution to preventive appendectomy in acute ileitis)].

Starting with one case of acute granulomatous appendicitis of their own observation, the authors review the scant literature on the subject (only 23 published cases to date) and advocate systematic appendicectomy in all isolated appendicular localizations of Crohn's disease. On the grounds that no post-appendicectomy fistulization has ever been reported in such patients, the authors recommend prophylactic appendicectomy also in the far more frequent cases of acute ileitis, to forestall the possibility of evolution into chronic Crohn's disease and the risk of missing a nongranulomatous acute appendicitis appearing with the same clinical symptoms.

Adult↗
PubMed1982

[Heteromultinodular goitres. Clinical and therapeutic study (author's transl)].

Heteromultinodular goitres are frequent and the involutive forms require early surgical treatment for three reasons: these goitres are usually resistant to medical treatment; association with carcinoma is not uncommon (6.5% in this series); and the late surgery is hazardous, as it leads to extensive tissue resection and often entails a risk of recurrence and lesions of the parathyroid glands. Post-operative hormonal treatment should be reserved to those patients who have had wide tissue resection (replacement therapy for life, monitored by TSH assays) or to young patients who require a 2-year protective treatment. Prevention may perhaps be achieved by systematic 2-3 years' treatment of active homogenous hyperplasia in young subjects. Hyperplasia has a natural tendency to nodular involution, in most cases over several decades, but curiously, 30-35 years' old adults with large multinodular goitres are being operated upon as though these lesions had greater evolutive potential. This could be an argument in favour of post-operative protective therapy in these young patients.

Adult↗
PubMedDate not supplied

Quality assurance in radiotherapy of head and neck tumors.

Radiation therapy represents an extensively experimented treatment modality for head and neck tumors. Recent studies have documented a close dependence of clinical results, especially in terms of local control and toxicity, on the radiation therapy quality. Thus the effort to improve the results of conventional radiotherapy has been achieved with the identification of new therapeutic modalities (non conventional fractionation, conformal therapy, fast neutron radiotherapy, concomitant or neoadiuvant chemotherapy) as well as with constant optimization of the accuracy of used procedures. Among them the following should be mentioned: 1) the systematic use of immobilization systems which enable a significant reduction in positioning errors; 2) checks before and during treatment by portal imaging which enable to identify and correct a relevant percentage of inaccuracies; 3) "in vivo" dosimetry which enables an overall assessment of treatment accuracy. The general evolution of the radiobiological knowledge occurred in recent years has introduced into radiotherapy of head and neck tumors new schemes of fractionation and new modalities of combination with other therapeutic procedures. Furthermore, while the widespread use of complex irradiation procedures calls for the urgent need of quality assurance of radiation treatments, this is by all means a mandatory requirement even in the most conventional clinical practice.

Head and Neck Neoplasms↗
PubMed2002

The pab1 gene of Coprinus cinereus encodes a bifunctional protein for para-aminobenzoic acid (PABA) synthesis: implications for the evolution of fused PABA synthases.

The pab1 gene of the basidiomycete Coprinus cinereus encodes PABA synthase, necessary for para-aminobenzoic acid production. The C. cinereus protein is bifunctional with an N-terminal glutamine amidotransferase domain and a C-terminal chorismate amination domain. In most bacteria, these two functions are encoded in separate genes (e.g., pabA and pabB of E. coli). Fused PABA synthases have so far been detected in actinomycetes, Plasmodium falciparum, fungi and Arabidopsis thaliana. Phylogenetic analysis shows that the fused PAB sequences form a tight group that also includes uncharacterized PabB homologues from several bacteria. Unfused bacterial PabA proteins group with the glutamine amidotransferase subunits of bacterial anthranilate synthases, independent of organismal systematics, indicating a complex and perhaps independent evolutionary origin. In contrast, unfused PabB group and fused PabA/B proteins form a monophyletic group on a branch separate from the chorismate amination subunits of anthranilate synthases, probably reflecting a need for recognition of different positions in the common substrate chorismate.

4-Aminobenzoic Acid↗
PubMed1998

Substitution bias, rapid saturation, and the use of mtDNA for nematode systematics.

Only relatively recently have researchers turned to molecular methods for nematode phylogeny reconstruction. Thus, we lack the extensive literature on evolutionary patterns and phylogenetic usefulness of different DNA regions for nematodes that exists for other taxa. Here, we examine the usefulness of mtDNA for nematode phylogeny reconstruction and provide data that can be used for a priori character weighting or for parameter specification in models of sequence evolution. We estimated the substitution pattern for the mitochondrial ND4 gene from intraspecific comparisons in four species of parasitic nematodes from the family Trichostrongylidae (38-50 sequences per species). The resulting pattern suggests a strong mutational bias toward A and T, and a lower transition/transversion ratio than is typically observed in other taxa. We also present information on the relative rates of substitution at first, second, and third codon positions and on relative rates of saturation of different types of substitutions in comparisons ranging from intraspecific to interordinal. Silent sites saturate extremely quickly, presumably owing to the substitution bias and, perhaps, to an accelerated mutation rate. Results emphasize the importance of using only the most closely related sequences in order to infer patterns of substitution accurately for nematodes or for other taxa having strongly composition-biased DNA. ND4 also shows high amino acid polymorphism at both the intra- and interspecific levels, and in higher level comparisons, there is evidence of saturation at variable amino acid sites. In general, we recommend using mtDNA coding genes only for phylogenetics of relatively closely related nematode species and, even then, using only nonsynonymous substitutions and the more conserved mitochondrial genes (e.g., cytochrome oxidases). On the other hand, the high substitution rate in genes such as ND4 should make them excellent for population genetics studies, identifying cryptic species, and resolving relationships among closely related congeners when other markers show insufficient variation.

Amino Acid Sequence↗
PubMed2025

The complete chloroplast genome of Secale strictum ssp. strictum provides insights into Triticeae evolution and breeding.

The complete chloroplast genome of Secale strictum ssp. strictum (Poaceae: Triticeae) was sequenced and analyzed to support its use in rye and wheat breeding. The genome is 137,063 bp long and includes a pair of inverted repeats (IRs; 21,580 bp each) that separate the small (SSC; 12,817 bp) and large (LSC; 81,086 bp) single-copy regions. It contains 113 genes: 74 protein-coding, 30 tRNA, four rRNA genes, and five conserved open reading frames. A total of 42 repeat sequences were identified, mainly in the LSC region, with direct repeats being most common. All mononucleotide SSRs consisted of A/T motifs. Seven highly variable regions were identified, offering potential as molecular markers for species identification and phylogenetic studies. Phylogenetic analysis based on 73 protein-coding genes confirmed the systematic placement of the species and showed that S. strictum ssp. strictum is closely related to S. cereale and other S. strictum accessions. This study presents the first complete plastome of S. strictum ssp. strictum, now available as a reference genome under GenBank accession number OL979486.

Genome, Chloroplast↗
PubMed1995

Comparison of human and mouse T-cell receptor variable gene segment subfamilies.

Like the immunoglobulin Igh-V and Igk-V gene families, the human or mouse TCRV gene families may be grouped into subfamilies displaying > 75% nucleic acid sequence similarity among their members. Systematic interspecies sequence comparisons reveal that most mouse Tcr-V subfamilies exhibit clear homology to human TCRV subfamilies (> 60% amino acid sequence similarity). Homologous pairs of TCRV genes in mice and humans show higher sequence similarity than TCRV genes from different subfamilies within either species, indicating transspecies evolution of TCRV genes. Mouse and human homologues show conservation of their relative map order, particularly in the 3' region and a similar sequential and developmentally programmed expression. When the V regions from both species were analyzed together, local length differences and conserved residues in the loop regions were revealed, characteristic of each of the four TCRV families.

Alleles↗
PubMed1995

Differential progression of complex and smooth stenoses within the same coronary tree in men with stable coronary artery disease.

OBJECTIVES: We sought to compare the evolution of complex and smooth stenoses within the same coronary tree in patients with stable coronary artery disease. BACKGROUND: Progression of coronary stenosis has prognostic significance and may be influenced by local and systemic factors. Stenosis morphology is a determinant of disease progression, but no previous study has systematically assessed progression of complex and smooth stenoses within the same patient. METHODS: We studied 50 men with stable angina who 1) had one complex coronary stenosis and one smooth stenosis in different noninfarct-related coronary vessels at initial coronary angiography, and 2) had a second angiogram after a median interval of 9 months (range 3 to 24). Patients with lesions > or = 10 mm long, at a major branching point or with > 85% diameter reduction were not included. Coronary lesions were measured quantitatively from comparable end-diastolic frames. Stenosis morphology was determined qualitatively by two independent observers. RESULTS: All patients remained in stable condition during follow-up. Progression, defined as an increase in diameter stenosis by > or = 15% was seen in only eight complex stenosis (16%) but in no smooth lesions (p < 0.01). The severity of complex stenoses changed more than that of corresponding smooth stenoses (mean +/- 1 SD 5.8 +/- 13% vs. -0.06 +/- 6%, p < 0.01). On average, the annual rate of growth was 11.4 +/- 28% and 1.5 +/- 14% for complex and smooth lesions, respectively (p < 0.01). CONCLUSIONS: Few coronary stenoses progress rapidly in stable angina. Complex and smooth coronary stenoses progress at different rates within the same coronary tree. complex stenosis morphology itself is an important determinant of progression of stenosis in patients with apparently clinically stable coronary artery disease.

Aged↗
PubMed1990

Host specificity of Strigiphilus owl lice (Ischnocera: Philopteridae), with the description of new species and host associations.

Three new species and 11 new host associations are described for the cursitans species group of the genus Strigiphilus, the only genus of Mallophaga confined to owls (Strigiformes). The new species are S. schemskei ex Bubo coromandus, S. garylarsoni ex Otus leucotis, and S. petersoni ex Ninox punctulata. This paper completes a taxonomic review of the cursitans species group and includes an updated host-parasite list. The host specificity of the group is reviewed, including features of the natural history of lice and their hosts that may have influenced the evolution of host-parasite associations. Although most members of the cursitans group are host specific, several cases of secondary transfer among ecologically related hosts are apparent. The significance of such transfers is discussed in light of attempts to employ data on host-parasite associations for host systematics.

Animals↗
PubMedDate not supplied

Sufficiently important difference: expanding the framework of clinical significance.

BACKGROUND: It is generally agreed that randomized controlled trials should be powered to detect small but clinically significant treatment effects. Toward these ends, minimal important difference (MID) was proposed as a benchmark for designing trials and for interpreting health-related quality-of-life instrument scores. MID was defined in 1989 as "the smallest difference in score in the domain of interest which patients perceive as beneficial and which would mandate, in the absence of troubling side effects and excessive cost, a change in the patient's management." OBJECTIVE: 1) To expand the idea of minimal clinically important difference so as to take into account harms as well as benefits. 2) To propose concepts and methods with which to do so. SUMMARY: The authors define sufficiently important difference (SID) as the smallest amount of patient-valued benefit that an intervention would require to justify associated costs, risks, and other harms. As a means toward estimation of SID, the authors propose benefit-harm tradeoff methods, in which domains of benefit and harm are systematically traded off against each other and assessed in relation to the global decision of whether a treatment choice is worthwhile. Specific SID estimates can be used to power and interpret clinical trials or to inform health services research and/or public health policy. This article briefly describes the evolution of the important difference concept and outlines similarities and differences between MID and SID.

Attitude to Health↗
PubMed2026

The Re-Emergence of Bundibugyo Ebolavirus in Uganda and the Democratic Republic of Congo: Epidemiological Drivers, Response Strategies, and Implications for Global Health Security.

Bundibugyo ebolavirus (BDBV) is one of the least studied species within the genus Orthoebolavirus (family Filoviridae), despite its capacity to cause severe Ebola virus disease (EVD) with substantial mortality. First identified during a 2007-2008 outbreak in Bundibugyo District, western Uganda (149 reported cases, 37 deaths; case-fatality rate [CFR] approximately 25-36%), BDBV re-emerged in 2012 in Orientale Province, Democratic Republic of the Congo (DRC) (57-59 cases, 29-34 deaths; CFR 34-58%), before resurfacing in Ituri Province, DRC, in April-May 2026. By 11 August 2026, this third outbreak had grown to 4566 laboratory-confirmed cases and 2128 deaths (CFR &#x2248; 47%) across five DRC provinces and Uganda, becoming the largest, fastest-growing BDBV epidemic on record and the second-largest Ebola-family outbreak overall. This narrative review, not a systematic review or meta-analysis, summarizes peer-reviewed literature, preprints, and official situation reports from WHO, Africa CDC, US CDC, ECDC, and national health ministries, identified through PubMed, Scopus, Web of Science, Google Scholar, and Embase from inception to 12 August 2026, to examine BDBV historical evolution, virology and pathogenesis, drivers of re-emergence, surveillance and response, therapeutic and vaccine gaps, and global health security implications. The 2026 outbreak, unfolding amid conflict and mass displacement in eastern DRC, has been marked by an estimated basic reproduction number of 1.4-2.1 (central estimate 1.71), disproportionate infection among healthcare workers (7.2% of confirmed cases in DRC, 20% in Uganda), and the continued absence of licensed BDBV-specific vaccines or therapeutics. Findings underscore the need for sustained genomic and ecological surveillance, decentralized rapid diagnostics, broadly protective pan-filovirus vaccines, conflict-sensitive response strategies, and strengthened Uganda-DRC collaboration. Because the evidence base for the ongoing outbreak remains preliminary, findings should be interpreted cautiously and revisited as further peer-reviewed data emerge.

Bundibugyo ebolavirus↗