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At least 19 recordsLinked to original sources
PubMed1978

Common variations of the radial writs extensors.

An anatomical study of the extensor carpi radialis longus (ECRL) and brevis (ECRB) in 173 upper limbs demonstrated abnormalities in 50%. Interconnecting tendons between the longus and brevis were found in 35% of limbs, the most common variation (26%) being a tendon arising proximally from the ECRL and inserting distally with the ECRB. In 42 limbs (24%) an extra muscle (the extensor carpi radialis intermedius) was present; many were large enough to activate a tendon transfer. Two case reports illustrate the use of extra muscles in the surgical rehabilitation of patients with paralytic disorders.

Adult↗
PubMed2026

Integrating rare and common variation in epilepsy genetics: from genetic architecture to penetrance and clinical expressivity.

Epilepsy genetics has often been interpreted through a useful but simplified dichotomous framework in which severe epilepsies, particularly developmental and epileptic encephalopathies, are attributed mainly to rare, high-effect variants, whereas more common epilepsies are viewed as arising largely from the cumulative effects of common, small-effect variation. Although this framework has been instrumental for gene discovery, molecular diagnosis, and mechanism-based treatment, it does not fully explain incomplete penetrance, intrafamilial phenotypic heterogeneity, or marked differences in severity among individuals sharing the same molecular diagnosis. Evidence from exome sequencing, copy number variant (CNV) studies, and genome-wide association studies increasingly suggests that rare SNVs/indels, CNVs, and common variant should not be interpreted as entirely independent risk sources, but may partially converge on shared genes, pathways, cell types, and neurobiological processes relevant to neuronal excitability, network stability, and seizure susceptibility. Here, we review evidence across epilepsy subtypes, focusing on convergence and divergence across the allelic spectrum, and discuss how polygenic background and other modifiers may influence penetrance and clinical expressivity among carriers of rare pathogenic variants and CNVs. We also consider implications for variant interpretation, genetic counseling, risk stratification, and precision medicine, while emphasizing that most rare-common integrated models remain insufficiently validated for routine clinical decision-making.

common variants↗
PubMed1976

Rhomboid flap principles and common variations.

The rhomboid flap was initially popularized by a Russian, Alexander Limberg, and modified by Claude Dufourmentel of Paris. Numerous variations on the flap have been proposed more recently by Webster and Gunter. This flap has found its way into the practice of most surgeons doing head and neck surgery, with its primary advantage being that it is an extremely simple flap operation to learn, with great versatility. The general principles and their clinical application are presented in order to increase proper utilization of the flap.

Humans↗
PubMed2026

HPRC2: A human pangenome reference with near-complete coverage of common genetic variation.

A pangenome reference overcomes the inherent limitation of any individual reference genome by integrating the variation present in a population. We present the Human Pangenome Reference Consortium's (HPRC) Release 2 (HPRC2), an openly available, second phase pangenome that is an approximately fivefold expansion in genome number over HPRC Release 1 (HPRC1) and measurable improvement in genome completeness, contiguity, and accuracy. Selecting samples with a principled algorithm prioritising common variant coverage, HPRC2 contributes 460 haplotypes that together capture over 99% of common variation observed in the All of Us Research Program v8 cohort. Combining high-coverage long and ultra-long reads with modern assemblers and polishers, we produce thousands of telomere-to-telomere (T2T) chromosomes, and relative to HPRC1 halve the number of structurally unreliable regions as well as individual base errors per haplotype. We complement the assemblies with whole genome multiple alignments and gene annotations, and derive formal pangenome coordinate systems for addressing off-reference variation, demonstrating that individual human genomes contain more than one hundred thousand variants not succinctly described with respect to existing reference genomes. We also present the first matched long-read backed pantranscriptome and panepigenome at this scale, provide continuous local-ancestry estimates spanning every genome, and outline a host of new tools and applications that leverage the pangenome resource for improved genomics analysis.

Journal Article↗
PubMed1976

Biological and analytical variation of commonly determined blood constituents in healthy blood donors.

The relative contributions of analytical error and non-systematic biological variation to the reference range for 19 commonly-determined blood chemistry values have been estimated during the course of studying 1000 healthy blood donors. Estimates of non-systematic biological variations are arrived at by determining the variation found in donors matched for factors known to affect blood chemistry such as age and sex, and deducting the within-batch analytical error which applied. Comparison of the within-batch and between-batch analytical precision with the biological variation showed that the percentage increases in the normal range attributable to between-batch analytical error varies between 1 and 29%. This contribution is particularly large in the case of the electrolytes and amounts to no less than 29% in the case of calcium. Apart from well-known relationships a remarkable lack of correlation between the concentration of the different constituents in health is demonstrated.

Adolescent↗
PubMed1989

Biologic variation of common hematologic laboratory quantities in the elderly.

Analytic, within-subject, and between-subject biologic variations were estimated for leukocytes, erythrocytes, hemoglobin, hematocrit, mean cell volume (MCV), mean cell hemoglobin (MCH), mean cell hemoglobin content (MCHC), platelets, and a three-component differential count (lymphocytes, monocytes, and granulocytes in terms of both concentration and percentage of leukocytes) in cohorts of 12 male and 12 female healthy elderly subjects. The assays were performed with an Ortho ELT-800 automated analyzer. The estimates of within-subject biologic variation were similar to published data on young subjects, indicating that this aspect of homeostasis is not compromised in the elderly. The data were used to derive objective analytic goals; goals were surpassed except for assays of erythrocytes, hematocrit, and the derived MCV, MCH, and MCHC. The changes required for serial results to be significantly different were determined and found to be generally valid because most quantities have no heterogeneity of within-subject variation. All quantities had significant individuality; in consequence, conventional population-based reference values are of limited utility, and screening using reference limits will not detect latent or early disease in many subjects.

Aged↗
PubMed1979

Intra-individual variation in commonly analyzed serum constituents.

Concentrations of 27 commonly estimated serum constituents were measured in blood sampled from 20 apparently healthy volunteers at 0830, 1230, and 1630 hours on each of four days, at weekly intervals. Time-dependent statistically significant (p less than or equal to 0.01) variation was observed in 12 of the constituents. The 15 constituents that showed no statistically significant diurnal variation included the immunoglobulins, other specific proteins, enzymes, cholesterol, calcium, copper, and magnesium. On the different days of the study consistent temporal patterns were observed in urea, creatinine, phosphate, zinc, bilirubin, triglyceride, total protein, and albumin. The magnitude of variation was particularly great in potassium, iron, zinc, and bilirubin. In general, day-to-day changes in concentration exceeded within-day changes, except for potassium, phosphate, and zinc, for which greater changes could be observed within-day than from one day to another at the same time.

Alanine Transaminase↗
PubMed1991

Variations of common bile duct diameter after endoscopic sphincterotomy.

Diameters of the common bile duct (CBD) and common hepatic duct (CHD) were measured before and after endoscopic sphincterotomy (EPT) in 100 patients. There was a significant reduction of the lumen diameter in both the CBD and CHD (p less than 0.01) after EPT. A comparison between 32 patients without symptoms (such as pain, residual stones, and elevated levels of liver enzymes) and 19 patients with remaining symptoms after EPT, showed a statistically significant reduction in both CBD and CHD diameters (p less than 0.001) in the former group, and no statistically proven changes in the diameters in the latter group, since a change of less than 1.5 mm was not considered significant. Therefore, the absence of a reduction or a dilatation of the diameter of the CBD after EPT may suggest that these patients may have persisting complaints after EPT. Measurements on models (phantoms) show that body position of the patient during endoscopic retrograde cholangiopancreatography (ERCP) has little and negligible influence on the measured diameters of the CBD and CHD.

Aged↗
PubMed1992

Cerebrospinal fluid protein variations in common to Alzheimer's disease and schizophrenia.

Analysis of silver stained two-dimensional (2D) gels of cerebrospinal fluid (CSF) from 27 patients with schizophrenia (SCZ) and 10 patients with Alzheimer's disease (AD) revealed an increase in the relative amount of a polypeptide of 18,000M(r) and isoelectric point of 6.5 when compared to the appropriate controls. This protein was identified by its electrophoretic characteristics and by immune analysis of Western blots as an isoform of alpha-2 haptoglobin, provisionally identified as alpha-2FS haptoglobin. Alzheimer's disease versus control CSF samples showed a 6.8-fold increase in the percent mean density value of this haptoglobin isoform (n = 10 AD vs 11 control; P > 0.025) while a 4.4-fold increase was observed in the schizophrenic patients (n = 17 SCZ vs 10 control; P > 0.001). Two additional polypeptides (proteins '127' and '128') of 40,000 M(r) and isoelectric points 5.7 and 5.9, respectively, described previously by this laboratory, were found in the CSF of 27% of schizophrenics, 23% of the Alzheimer's disease patients, and 4% of the controls in the current study. The presence of proteins 127 and 128, as well as the increased concentrations of alpha-2 haptoglobin in the CSF of Alzheimer's disease and schizophrenic patients, may be useful as diagnostic biological markers. They may also indicate a common pathophysiology between these diseases.

Acute-Phase Proteins↗
PubMed1977

An estimate of the amount of genetic variation in the common mussel Mytilus edulis.

Allozyme variation in a population of the common mussel Mytilus edulis in Mumbles, South Wales, has been studied by starch gel electrophoresis. On the basis of data obtained for 34 loci, we estimate the proportion of loci polymorphic to be 30%. Using only the 29 loci for which individual genotypes can be accurately typed, the average heterozygosity is estimated to be 9.5 +/- 3.6%. The calculated expected average heterozygosity based on Hardy-Weinberg expectations is identical with the observed value. Allele frequency data at six polymorphic loci are given for several other British populations. There is no significant geographic heterogeneity. The results are discussed in relation to genetic adaptive strategies and are shown to be inconsistent with the predictions of the neutral hypothesis.

Alleles↗
PubMed1975

Surgical anatomy of the mesocaval shunt.

Having encountered wide variations in the surgical trunk of the superior mesenteric vein and its arterial relationships during the performance of mesocaval shunts, we believed it would be rewarding to evaluate this vessel in a series of 36 cadavers. In two of these 36 instances, we determined that the anatomic findings precluded the performance of a mesocaval shunt. In ten other instances, even though a shunt could be performed, a knowledge of these variations could prevent operative complications. The most common variation was a bifurcation of the superior mesenteric vein at or proximal to the site of the surgical trunk. Another variation which could cause operative difficulties was unusual positions of the superior mesenteric artery and its major branches in relation to the vein at the level of the surgical trunk. A knowledge of these variations in the surgical anatomy of the superior mesenteric vein should make mesocaval shunts easier and safer to perform.

Humans↗
PubMed1992

Individual susceptibility to toxicity.

Individual variation in susceptibility to chemical toxicity may be due to differences in toxicokinetic patterns or effect modification. Well-documented interspecies genetic differences in susceptibility to chemicals had lead to studies of such variation also within species. Epidemiological evidence now suggests that common variations, particularly in the P-450 enzymes, may play a major role in determining individual susceptibility to chemically-induced disease. Physiologic factors are involved in the particular susceptibility of the fetus, the newborn, and the old. Constitutional susceptibility is also affected by acquired conditions, including chronic disease, such as diabetes mellitus. Perhaps the most complex area relates to the increase in vulnerability caused by previous or contemporary exposure to other factors, thus eliciting, e.g., synergistic effects. Although amply demonstrated by experimental studies, epidemiological or clinical confirmation is generally lacking. One hypothesis suggests that a chemical exposure may affect the reserve capacity of the body, though not resulting in any immediate adverse effect. Subsequently, the body becomes unable to compensate for an additional stress, and toxicity then develops. Epidemiological approaches are available and need to be expanded. Research in this area has potential ethical implications which should be dealt with in an open, informed forum.

Age Factors↗
PubMed1976

The remodeling of the edentulous mandible.

In a sample of mandibles having complete or nearly complete loss of dentition, the left half of each mandible was serially sectioned. The entire perimeter of each section was analyzed for the distribution of resorptive and depository periosteal surfaces, and from this information, the fields of remodeling were mapped for the mandible as a whole. The most common patterns of combined resorption-deposition and the range of variations were then determined. The over-all distribution of remodeling fields in the edentulous mandible differs markedly from that in the young, growing mandible. In most of the edentulous specimens, the surface of the basal bone on both the medial and lateral sides of the corpus is of a depository nature. The overlying alveolar regions on both the lingual and buccal sides, however, are characteristically resorptive. Significantly, the placement of the reversal line between the alveolar resorptive and the basal depository areas is much lower (i.e., at the level of the mental foramen) on the buccal side. Except for its inferior part, the lateral side of the ramus tends to be largely resorptive in character, and the posterior half of the lingual side also tends to be resorptive. Unlike the child's mandible, the posterior border of the ramus is resorptive, and the posteroanterior dimension of the ramus (not the whole mandible) becomes reduced and narrowed in conjunction with resorption along the anterior border. However, the amount removed from the anterior ramus is actually added to the dimension of the corpus, which becomes longer. Further, removal from the posterior ramus border does not affect the over-all length of the mandible unless condylar reduction is also involved. Also, over-all arch length is not decreased, because the surface of the mental protuberance is retained as a depository type of field (or at least does not become actively resorptive). The corpus-ramus angle (not gonial angle) is increased in the antegonial region. Because of the opening of this angle, over-all mandibular length as well as arch length is increased. In about half of the specimens, arch width was not decreased, because the lateral side of the corpus is usually of a depository nature. Notching of the anterior side of the condylar neck and the inferior part of the anterior ramus border is associated with resorptive fields in these regions, changes that are presumed to be a consequence of pressure contacts made with the articular tubercle and the maxillary tuberosity, respectively, in conjunction with a forward rotation of the whole mandible. The inferior direction of corpus realignment relative to the basal part of the ramus also increases the notching effect in the antegonial region, an effect augmented by the presence of the resorptive field in the notch itself. Certain specific variations commonly occur in several major regions of the mandible on both the lateral and medial sides...

Alveolar Process↗
PubMed1990

Continuum analysis of common branching patterns in the human arch of the aorta.

A model is proposed for describing common variations in the arrangement of branches on the arch of the human aorta, and the model is used to analyze data from 123 human arches. The analysis allows the observed variations to fall freely along a continuous spectrum, rather than be confined to discrete categories as is commonly done at present. The results thus describe these variations in a more natural way and throw some new light on their likely source.

Aorta, Thoracic↗