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PubMed1977

[Cytologic diagnosis of myxoid liposarcomas of soft tissues].

Myxoid sarcomas are characterized by the presence of branching capillaries in preparations around which lipogenesis is proceeded (unilocular and multilocular). Fat is chemically neutral. The cell content is represented by two basic kinds of cells: 1. stellate lipoblast -- a cambial element of the tumor, and 2. mature lipocyte -- a terminal stage of the differentiation of stellate lipoblast. Moreover, variable intermediate forms demonstrating the stage of lipoge nesis may be encountered. The differential diagnosis between the former and intramuscular myxoma and neurinoma (Antony B type) was made. The work is based on the analysis of 10 cases of myxoid liposarcomas.

Adult↗
PubMed1997

Risk factors and clinical outcomes between fungal and bacterial keratitis: a comparative study.

PURPOSE: Previous studies on fungal and bacterial keratitis were descriptive single case series analysis. We conducted a hospital-based retrospective study to evaluate fungal and bacterial keratitis using a case-control design to compare risk factors and clinical outcomes. METHODS: Twenty-nine cases of culture-positive fungal keratitis seen over a 5-year period were compared to 51 cases of culture-positive bacterial keratitis seen over a 21 months period. Using bacterial keratitis as the reference group, case-control odds ratios (OR) for predisposing factors and cohort relative risks (RR) for clinical outcomes associated with fungal keratitis were derived. Mantel-Haenszel adjustment procedures were used to examine the respective roles of confounding and intermediate variables. RESULTS: Compared to bacterial keratitis, fungal keratitis was significantly more likely to be associated with ocular trauma (OR = 2.69, 95% confidence interval [CI], 1.06-6.86) but significantly less likely to be associated with contact lens wear (OR = 0.16, 95% CI, 0.04-0.67) and preexisting ocular diseases (OR = 0.23, 95% CI, 0.07-0.72). Fungal keratitis was more likely to perforate than bacterial keratitis (RR = 5.28, 95% CI, 1.35-20.66) and to require penetrating keratoplasty (OR = 5.86, 95% CI, 2.06-16.69). CONCLUSIONS: Fungal keratitis appears more likely to result from ocular trauma, whereas bacterial keratitis is more likely to result from contact lens wear and pre-existing ocular diseases. Fungal keratitis is more likely than bacterial keratitis to result in perforation and require penetrating keratoplasty.

Adolescent↗
PubMed2002

Better anticoagulation control improves survival after valve replacement.

OBJECTIVE: We sought to assess the effect of anticoagulation control on long-term survival after valve replacement with the Medtronic Hall valve (Medtronic, Inc, Minneapolis, Minn). METHODS: Prospective follow-up data, including 82,297 international normalized ratios, were collected for 1476 patients undergoing single valve replacement with the Medtronic Hall valve between 1979 and 1994, with follow-up to the end of 1998. After excluding 204 patients who either died within 30 days or had fewer than 10 international normalized ratios recorded beyond 30 days, there were 10,203 patient years of follow-up for analysis. Anticoagulation variability was measured as the percentage of international normalized ratios outside a target range of 2.0 to 4.0 for each patient. RESULTS: Linearized rates for late death rose progressively with increasing deciles of anticoagulation variability for both aortic and mitral valve replacement (2.7% and 3.3% per year, respectively, in deciles 1 and 2 up to 9.5% and 14.6% per year, respectively, in deciles 6-10; P <.001). Survival at 15 years after aortic valve replacement was 59% for low anticoagulation variability (deciles 1 and 2), 55% for intermediate anticoagulation variability (decile 3), and 28% for high anticoagulation variability (deciles 4-10); survivals at 15 years after mitral valve replacement were 56%, 42%, and 24%, respectively (P <.001 between low-intermediate anticoagulation variability and high anticoagulation variability for both aortic and mitral valve replacement). On multivariate analysis, significant predictors of reduced survival were anticoagulation variability per 20% increase (hazard ratio, 1.8), diabetes (hazard ratio, 1.6), decade of age (hazard ratio, 1.6), concomitant coronary artery bypass grafting (hazard ratio, 1.5), male sex (hazard ratio, 1.4), hypertension (hazard ratio, 1.4), New York Heart Association class III or IV (hazard ratio, 1.3), and non-sinus rhythm (hazard ratio, 1.2). Patients with low anticoagulation variability who were in sinus rhythm and did not have diabetes, coronary bypass grafting, or hypertension had survivals equal to those of the age- and sex-matched general population at 15 years. The incidence of valve-related deaths was significantly higher with high anticoagulation variability compared with the incidence with low-intermediate anticoagulation variability for both aortic (1.4% vs 0.5% per year, P <.001) and mitral valve replacement (1.5% vs 0.5% per year, P <.001). By means of univariate analysis, high anticoagulation variability was significantly associated with New York Heart Association class III or IV at 5 years postoperatively (P <.001) and with age of greater than 60 years at the time of the operation (P =.002). CONCLUSIONS: High anticoagulation variability is the most important independent predictor of reduced survival after valve replacement with a mechanical valve. Better anticoagulation control should improve survival.

Adolescent↗
PubMed1985

Variable expression of intermediate filament proteins during embryonic development of human optic nerve.

The intermediate filament protein composition of human optic nerve and tract was analyzed by two-dimensional gel electrophoresis. Optic nerves were analyzed at 15, 19, 22, and 24 weeks of embryonic development and the results were compared with the composition of adult optic nerve. The optic tract was analyzed at the later stages of development. The proteins were visualized by Coomassie blue staining and immunoblotting with specific antibodies to glial fibrillary acidic protein (GFAP) and vimentin. The 70K and 150K neurofilament proteins were first observed at 24 weeks. At 15 weeks of development, only trace amounts of GFAP were observed and vimentin was the predominant intermediate filament protein. In contrast, there was more than twice as much GFAP as vimentin in the adult optic nerve. The results also showed that the ratio of GFAP to vimentin is higher in the optic tract than in the optic nerve during development, whereas in adult tissue, the ratio is the same for the two regions. In pathological situations with axonal dropout, a complete loss of neurofilament proteins was observed. The amounts of both GFAP and vimentin were the same for both the normal and involved optic nerve. These results are discussed in terms of the development of the optic nerve.

Glial Fibrillary Acidic Protein↗
PubMed2002

Genetic variability of the main intermediate host of the Schistosoma mansoni in Brazil, Biomphalaria glabrata (Gastropoda: Planorbidae) assessed by SSR-PCR.

The genetic variability of Brazilian Biomphalaria glabrata populations was studied using SSR-PCR. This technique is a variant of the polymerase chain reaction (PCR), which consists of using a single primer directed towards microsatellite regions under high stringency reaction conditions. Twenty snails of each population from eight distant Brazilian localities were analyzed. Morphology and PCR-RFLP were used for previous specific identification of the snails. Bands generated after gel electrophoresis of the SSR-PCR products of each snail were used to study intra- and interpopulation genetic variability. Fifty-five prominent bands were considered in a pairwise band comparison for the determination of genetic variability. Genetic variability was greater between populations than within populations. Snail populations from the field and the laboratory presented almost no genetic differences. No relationship between genetic variability and geographic distance was found. SSR-PCR proved to be a good alternative molecular tool for the population study of B. glabrata.

Animals↗
PubMed2004

What defines intermediate-risk prostate cancer? Variability in published prognostic models.

PURPOSE: To assess the efficacy of a variety of prognostic models in the definition of intermediate-risk prostate cancer and to compare them to our own empiric model. METHODS AND MATERIALS: Two hundred fifty-six consecutive men with prostate adenocarcinoma treated with external beam radiotherapy alone were studied. Biochemical failure (defined as 3 consecutive PSA rises or the initiation of androgen deprivation therapy) was examined using univariate, multivariate, and recursive partitioning analyses. The risk classification model used in our department was then compared to a number of published models to assess the relative performance of each in discriminating risk groups. RESULTS: At a median follow-up of 62.4 months, the 5-year Biochemical failure-free survival (bFFS) was 46.8% for the overall group. This relates to 5-year bFFS of 77.8%, 51.1%, and 33.8% based on our institutional criteria for low-, intermediate-, and high-risk features, respectively. All the models examined showed an outcome group with a comparatively similar poor outcome when applied to our data. Large variation was seen in the intermediate-risk groups, with 5-year bFFS ranging from 38.1% to 51.1%. Good risk categories had similar large variations. All published models showed inability to delineate three significantly different outcome groups. Recursive partitioning analysis derived categories based on combinations of PSA (with cutpoints at 42.4, 20, and 10.6 ng/mL) and Gleason score (with cutpoints at 2-6 and 7-10) only. CONCLUSIONS: Large variations in the relative performance of a number of prognostic models are shown when applied to our local data. The prognostic efficacy of PSA and biopsy Gleason score is reiterated, although other factors will need to be explored to further improve the performance of prognostic models, particularly in defining the intermediate-risk subset of prostate cancer.

Adult↗
PubMed1999

Racial/ethnic analysis of selected intermediate outcomes for hemodialysis patients: results from the 1997 ESRD Core Indicators Project.

Principal goals of the End-Stage Renal Disease (ESRD) Core Indicators Project are to improve the care provided to ESRD patients and to identify categorical variability in intermediate outcomes of dialysis care. The purpose of the current analysis is to extend our observations about the variability of intermediate outcomes of ESRD care among different racial and gender groups to a previously unreported group, Hispanic Americans. This group is a significant and growing minority segment of the ESRD population. A random sample of Medicare-eligible adult, in-center, hemodialysis patients was selected and stratified from an end-of-year ESRD patient census for 1996. Of the 6,858 patients in the final sample, 45% were non-Hispanic whites, 36% were non-Hispanic blacks, and 11% were Hispanic. Whites were older than blacks or Hispanics (P < 0.001). Hispanics were more likely to have diabetes mellitus as a primary diagnosis than either blacks or whites (P < 0.001). Even though they received longer hemodialysis times and were treated with high-flux hemodialyzers, blacks had significantly lower hemodialysis doses than white or Hispanic patients (P < 0.001). The intradialytic weight losses were greater for blacks (P < 0.05). The delivered hemodialysis dose was lower for blacks than for whites or Hispanics whether measured as a urea reduction ratio (URR) or as the Kt/V calculated by the second generation formula of Daugirdas (median 1. 32, 1.36, and 1.37, respectively, P < 0.001). Hispanics and whites had modestly higher hematocrits than blacks (33.2, 33.2, and 33.0%, respectively, P < 0.01). There was no significant difference among groups in the weekly prescribed epoetin alfa dose ( approximately 172 units/kg/week). A significantly greater proportion of Hispanic patients had transferrin saturations >/=20% compared with the other two groups (P < 0.001). Logistic regression modeling revealed that whites were significantly more likely to have serum albumin <3. 5(BCG)/3.2(BCP) gm/dL (OR 1.4, p < 0.01); blacks were significantly more likely to have a delivered Kt/V < 1.2 (OR 1.4, P < 0.001) and hematocrit <30%, (OR 1.2; P < 0.05) and both blacks and Hispanics were significantly more likely to have a delivered URR < 65% (OR 1.5, P < 0.001 and 1.2, P < 0.05, respectively).

Adolescent↗
PubMed1995

Nonrandom frequency patterns of synonymous substitutions in homologous mammalian genes.

All 69 homologous coding sequences that are currently available in four mammalian orders were aligned and the synonymous positions of quartet and duet (fourfold and twofold degenerate) codons were divided into three classes (that will be called conserved, intermediate, and variable) according to whether they show no change, one change, or more than one change, respectively. We observed (1) that the frequencies of conserved, intermediate, and variable positions of quartet and duet codons are different in different genes; (2) that the frequencies of the three classes are significantly different from expectations based on a random substitution process in the majority of genes (especially for GC-rich genes) for quartet codons and in a minority of genes for doublet codons; and (3) that the frequencies of the three classes of positions of quartet codons are correlated with those of duet codons, the conserved positions of quartet and duet codons being, in addition, correlated with the degree of amino acid conservation. Our main conclusions are that synonymous substitution frequencies: (1) are gene-specific; (2) are not simply the result of a stochastic process in which nucleotide substitutions accumulate at random, over time; and (3) are correlated in quartet and duet codons.

Animals↗
PubMed2001

Spatio-temporal genetic variability in the schistosome intermediate host Biomphalaria pfeifferi.

Genetic variation among temporally and spatially defined populations of the schistosome intermediate host, Biomphalaria pfeifferi, was analysed using RAPD markers. Snails were collected from each of eight sites that were 1-20 km apart, on four occasions, over a 2-year period. High levels of genetic variability were found within populations, between populations and between collections. Spatial differentiation and intrapopulation similarity were highest during periods of drought and were lowest following heavy rainfall. Temporal variability, consistent with founder effects, genetic drift and/or differential parasite pressure, was of similar or greater magnitude to that of the spatial variability. The results not only demonstrate that spatio-temporal sampling is necessary to understand the population genetics of short-lived species in variable habitats, but also provide empirical data to support current theoretical models of host-parasite co-evolution.

Analysis of Variance↗
PubMed1962

Autoradiographic study of DNA synthesis and the cell cycle in spermatogonia and spermatocytes of mouse testis using tritiated thymidine.

Mice were injected intraperitoneally with 15 microc of H(3)-thymidine. The time course of the labeling in spermatogonia and spermatocytes was studied by using autoradiography on 5 micro sections stained by the periodic acid-Schiff method and hematoxylin over a period of 57 hours after injection. Four generations of type A (called AI, AII, AIII, and AIV), one of intermediate, and one of type B spermatogonia occur in one cycle of the seminiferous epithelium. The average life span is about the same in all spermatogonia, i.e., about 27 to 30.5 hours. The average pre-DNA synthetic time, including the mitotic stages from metaphase through telophase and the portion of interphase preceding DNA synthesis, is also not very different, ranging between 7.5 and 10.5 hours. A remarkable difference exists, however, in the duration of DNA synthesis and of the post-DNA synthetic period. The average DNA synthetic time is very long and is highly variable in type B (14.5 hours), a little shorter and less variable in intermediate (12.5 hours) and AIV (13 hours) spermatogonia, and much shorter and very constant in AIII (8 hours), AII and AI (7 to 7.5 hours) spermatogonia. Conversely, the average post-DNA synthetic time, corresponding essentially to the duration of the prophase, is short and very constant in type B (4.5 hours), longer and variable in intermediate (6 hours) and AIV (8 hours) spermatogonia, and much longer and much more variable in AIII (11 hours), AII and AI (14 hours) spermatogonia. The premeiotic synthesis of DNA takes place in primary spermatocytes during the resting phase and terminates just before the visible onset of the meiotic prophase. Its average duration is 14 hours. No further synthesis of DNA takes place in later stages of spermatogenesis.

Animals↗
PubMedDate not supplied

The relation between religiosity, selected health behaviors, and blood pressure among adult females.

BACKGROUND: This study examined the association between blood pressure (BP), selected health behaviors, and various dimensions of religiosity among females. METHODS: Data were obtained on 112 females who were at least 35 years of age and of Judeo-Christian faith. Resting BP measures were taken with an automated sphygmomanometer, height and weight were measured to determine body mass index (BMI), and intermediate health variables (e.g., physical activity, smoking, diet, and alcohol consumption) were measured by questionnaire. A multifactorial questionnaire was used to assess various dimensions of religiosity. Multiple regression path analyses were conducted to determine the direct and indirect effects of religiosity on BP with age and BMI controlled statistically. RESULTS: The direct effects of religiosity on SBP and DBP were more substantial than the indirect effects through the intermediate health variables, suggesting that religiosity may be associated with lower levels of BP via a direct pathway, such as improving the ability to cope with stress. In general, DBP was more influenced by religiosity than SBP and the dimensions of "intrinsic religiosity" and "religious coping" were most influential. Results also indicated that "religious experiences" may exert a greater beneficial effect on DBP in older (50-80 years) age groups. CONCLUSIONS: These results support a direct relationship between religiosity and BP, rather than an indirect effect through intermediate health behaviors.

Adaptation, Psychological↗
PubMed2001

Predicting secondary progression in relapsing-remitting multiple sclerosis: a Bayesian analysis.

With the aid of a Bayesian statistical model of the natural course of relapsing remitting Multiple Sclerosis (MS), we identify short-term clinical predictors of long-term evolution of the disease, with particular focus on predicting onset of secondary progressive course (failure event) on the basis of patient information available at an early stage of disease. The model specifies the full joint probability distribution for a set of variables including early indicator variables (observed during the early stage of disease), intermediate indicator variables (observed throughout the course of disease, prefailure) and the time to failure. Our model treats the intermediate indicators as a surrogate response event, so that in right-censored patients, these indicators provide supplementary information pointing towards the unobserved failure times. Moreover, the full probability modelling approach allows the considerable uncertainty which affects certain early indicators, such as the early relapse rates, to be incorporated in the analysis. With such a model, the ability of early indicators to predict failure can be assessed more accurately and reliably, and explained in terms of the relationship between early and intermediate indicators. Moreover, a model with the aforementioned features allows us to characterize the pattern of disease course in high-risk patients, and to identify short-term manifestations which are strongly related to long-term evolution of disease, as potential surrogate responses in clinical trials. Our analysis is based on longitudinal data from 186 MS patients with a relapsing-remitting initial course. The following important early predictors of the time to progression emerged: age; number of neurological functional systems (FSs) involved; sphincter, or motor, or motor-sensory symptoms; presence of sequelae after onset. During the first 3 years of follow up, to reach EDSS> or =4 outside relapse, to have sphincter or motor relapses and to reach moderate pyramidal involvement were also found to be unfavourable prognostic factors.

Age of Onset↗
PubMed1997

Intermediate-term outcome of variable dose mitomycin C filtering surgery.

PURPOSE: Trabeculectomy with adjunctive mitomycin C is associated with high success rates in studies with follow-up of less than 1 year. This report evaluates the visual and intraocular pressure (IOP) outcome in eyes after trabeculectomy with adjunctive mitomycin C 1 to 3 years after surgery in a predominantly white group (98.1%). METHODS: The records of 157 eyes of 157 consecutive patients, aged 18 or older, who underwent mitomycin C trabeculectomies for uncontrolled glaucoma of various causes were reviewed. All surgeries were performed between April 1991 and June 1993. The concentration of mitomycin C varied from 0.2 to 0.5 mg/ml and was applied for 30 seconds to 5 minutes (only one patient received 0.2 mg/ml). Of the 157 eyes, 110 eyes were at high risk for failure (previous surgeries or inflammatory glaucoma). Thirty-nine eyes had preoperative IOP < or = 21 mmHg. RESULTS: The mean preoperative IOP was 29.4 +/- 10.3 mmHg. This was reduced to 13.0 +/- 7.6 mmHg at 1 year, 11.5 +/- 6.4 mmHg at 2 years, and 13.4 +/- 7.3 mmHg at 3 years. Cumulative survival rate by life-table analysis was 94.2% +/- 1.9% at 1 year, 92.1% +/- 2.4% at 2 years, and 88.7% +/- 4.0% at 3 years, where failure was defined as reoperation for control of IOP. Complications included cataract formation-progression (n = 31), hyphema (n = 26), choroidal detachment (n = 21), hypotony maculopathy (n = 5), and endophthalmitis (n = 2). Vision deteriorated in 29 eyes and improved by 2 or more Snellen visual acuity lines in 29 eyes. CONCLUSION: The IOP reduction after mitomycin C filtering surgery is sustained in the intermediate-term, 1 to 3 years, follow-up period.

Adult↗
PubMed1996

A prospective randomized study comparing short- and intermediate-term perioperative outcome variables after spinal or general anesthesia for lumbar disk and laminectomy surgery.

General or regional anesthesia may be used for lumbar laminectomy. To determine whether one method is superior, 122 patients were randomly assigned to receive either a standard general anesthetic (GA) or spinal anesthesia (SA) supplemented with intravenous (IV) propofol sedation. Data from the intraoperative period through hospital discharge were collected and compared. Demographically, both groups were similar. Total anesthesia (131.0 +/- 4.3 vs 106.6 +/- 3.2 min) and surgical times (81.5 +/- 3.6 vs 67.1 +/- 2.8 min) were longer in the GA group. Intraoperative hemodynamics were similar between groups except that the incidence of increased blood pressure was more frequent with GA (26.2% vs 3.3%). Blood loss was less during SA (133 +/- 18 mL vs 221 +/- 32 mL). Postanesthesia care unit (PACU) heart rates and mean arterial pressures were higher in the GA group. Peak pain scores in the PACU were higher after GA compared with SA (58 +/- 4 vs 22 +/- 3) as were the number of patients who required analgesics. Severe nausea was more common in the GA group both in the PACU and during the 24 h after surgery. Analgesic requirements after discharge from the PACU, urinary retention, and days in the hospital did not differ between groups. This study suggests that SA may be superior to GA both intraoperatively and postoperatively for lumbar spine procedures lasting less than 2 h.

Adult↗
PubMed2000

Comparison of human immunodeficiency virus type 1 Pr55(Gag) and Pr160(Gag-pol) processing intermediates that accumulate in primary and transformed cells treated with peptidic and nonpeptidic protease inhibitors.

Human immunodeficiency virus type 1 (HIV-1) produces two polyproteins, Pr55(Gag) and Pr160(Gag-Pol), that are cleaved into mature functional subunits by the virally encoded protease. Drugs that inhibit this protease are an important part of anti-HIV therapy. We studied the ordered accumulation of Gag and Gag-Pol processing intermediates by variably blocking the protease with HIV-1 protease inhibitors (PIs). Variable protease inhibition caused accumulation of a complex pattern of processing intermediates, which was the same after incubating HIV-1-infected cells with increasing concentrations of either one of the peptidomimetic inhibitors indinavir, saquinavir (SQV), ritonavir (RTV), nelfinavir, and SC-52151 or one of the nonpeptidomimetic inhibitors DMP450, DMP323, PNU-140135, and PNU-109112 for 3 days. The patterns of Gag and Gag-Pol processing intermediate accumulation were nearly identical when the following were compared: cell- versus virion-associated proteins, HIV-1-infected transformed cell lines versus primary human peripheral blood mononuclear cells (PBMCs) and HIV-1(MN) versus HIV-1(IIIB) virus strains. RTV was a more potent inhibitor of p24 production in PBMCs than SQV by approximately 7-fold, whereas SQV was a more potent inhibitor in transformed cells than RTV by approximately 30-fold. Although the antiretroviral potency of HIV-1 PIs may change as a function of cell type, the polyprotein intermediates that accumulate with increasing drug concentrations are the same. These results support sequential processing of Gag and Gag-Pol polyproteins by the HIV-1 protease and may have important implications for understanding common cross-resistance pathways.

Cell Transformation, Viral↗
PubMed1988

Noninvasive identification of severe coronary artery disease using exercise radionuclide angiography.

The ability of exercise radionuclide angiography to predict the risk of having significant left main or three vessel coronary artery disease was examined in 681 patients who underwent both radionuclide and coronary angiography. There were significant differences in multiple variables between patients with or without such disease. Logistic regression analysis identified seven variables as independently predictive of the presence of left main or three vessel disease. Using these variables, low, intermediate and high probability groups could be identified. The four most important variables--the magnitude of exercise ST segment depression, peak exercise ejection fraction, peak exercise rate-pressure product and sex of the patient--can provide practical estimates of the risk of having left main or three vessel disease. Exercise radionuclide angiography can provide a clinically useful noninvasive estimate of the risk of having significant left main or three vessel disease.

Angiography↗
PubMed2000

Clinical prediction of acute aortic dissection.

BACKGROUND: Clinical criteria for aortic dissection are poorly defined. Thus, 35% of aortic dissections remain unsuspected in vivo, and 99% of suspected cases can be refuted. OBJECTIVE: To identify independent predictors of acute aortic dissection and create a prediction model for facilitated estimation of the individual risk of dissection. METHODS: Two hundred fifty patients with acute chest pain, back pain, or both; absence of an established differential diagnosis of the pain syndrome; and clinical suspicion of acute aortic dissection were evaluated for the presence of 26 clinical variables in a prospective, observational study. Multivariate analysis was performed to create a prediction model of aortic dissection. RESULTS: Aortic pain with immediate onset, a tearing or ripping character, or both; mediastinal widening, aortic widening, or both on chest radiography; and pulse differentials, blood pressure differentials, or both (P<.001 for all) were identified as independent predictors of acute aortic dissection. Probability of dissection was low with absence of all 3 variables (7%), intermediate with isolated findings of aortic pain or mediastinal widening (31% and 39%, respectively), and high with isolated pulse or blood pressure differentials or any combination of the 3 variables (> or = 83%). Accordingly, 4% of all dissections were assigned to the low-probability group, 19% to the intermediate-probability group, and 77% to the high-probability group of aortic dissection. CONCLUSIONS: Assessment of 3 clinical variables permitted identification of 96% of the acute aortic dissections and stratification into high-, intermediate-, and low-probability groupings of disease. With better selection for prompt diagnostic imaging, this prediction model can be used as an aid to improve patient care in aortic dissection. Arch Intern Med. 2000;160:2977-2982

Aged↗
PubMed2001

Craniodental variation in Paranthropus boisei: a developmental and functional perspective.

What levels and patterns of craniodental variation among a fossil hypodigm are necessary to reject the null hypothesis that only a single species is sampled? We suggest how developmental and functional criteria can be used to predict where in the skeleton of fossil hominins we should expect more, or less, within-species variation. We present and test three hypotheses about the factors contributing to craniodental variation in extant primate taxa, and then apply these results to the interpretation of the P. boisei hypodigm. Within the comparative samples of extant Homo, Pan, Gorilla, Pongo, and Colobus, variables from the cranial base, neurocranium, and face that are not subject to high magnitudes of strain have consistently lower levels of intraspecific variation than variables from regions of the face subject to high levels of strain. Dental size variables are intermediate in terms of their reliability. P. boisei is found to have a low degree of variability relative to extant primates for variables shown to be generally useful for testing taxonomic hypotheses. Contrary to the claims of Suwa et al. ([1997] Nature 389:489-492), the recently discovered material from Konso falls within the range of variation of the "pre-Konso" hypodigm of P. boisei for available conventional metrical variables. Those aspects of the Konso material that appear to extend the range of the P. boisei hypodigm involve regions of the skull predicted to be prone to high levels of within-species variation. The approach used in this study focuses on craniodental data, but it is applicable to other regions of the skeleton.

Animals↗