Calcified cartilage differs in patients with end-stage primary osteoarthritis and secondary osteoarthritis due to rheumatoid arthritis of the hip joint

Objectives: Despite distinct aetiologies, the end-stages of primary osteoarthritis (OA) and secondary OA are described by common radiological features. However, the morphology of the bone-cartilage unit may differ depending on the pathogenesis. In this cross-sectional study, we aimed to investigate the histological differences in the bone-cartilage unit of the femoral head between patients with primary OA and secondary OA due to rheumatoid arthritis (RA).Method: Femoral heads were obtained from 12 patients with primary OA, six patients with secondary OA due to RA, and 12 control subjects. The femoral heads were investigated using stereological methods to ensure unbiased quantification.Results: The volume (mean difference [95% confidence interval]) (2.1 [0.5;3.8] cm³, p = 0.016) and thickness (413 [78.9;747] µm, p = 0.029) of the articular cartilage and the thickness of the calcified cartilage (56.4 [0.4;113] µm, p = 0.017) were larger in patients with primary OA than in patients with secondary OA due to RA. Femoral head volume (1.2 [-3.6;6.1] cm³, p = 0.598), bone volume fraction (-1.1 [-2.8;5.1] cm³, p = 0.553), subchondral bone thickness (-2.5 [-212;207] µm, p = 0.980), and osteophyte area (25.3 [-53.6;104] cm², p = 0.506) did not differ between patients.Conclusion: The thicker calcified cartilage in primary OA preceding the loss of articular cartilage can be attributed to endochondral ossification. Patients with secondary OA due to RA had severely thinner calcified cartilage as the pathogenesis is driven by inflammation and is characterized by a generalized and more severe loss of articular cartilage.

CO-score; a new method for quality assessment of radiology reports

INTRODUCTION

Studies on assessing radiology reports commonly calculates sensitivity, specificity and accuracy, which estimates if the observer has tendency to overdiagnose, overlook pathology, or both. This pilot study examines a new method for assessing the quality of radiology reports, based on the patients' clinical outcome.

METHODS

Two observers evaluated five hundred reports by four experienced reporting radiographers on X-ray images of the appendicular skeleton. The observers categorised the reports as true or false and gradated the quality of the report from 1 to 3 based on the patients' clinical outcome. We developed a new performance score, called the Consequence of Clinical Outcome (CO-score), which combines the amount of incorrect reports and the severity of errors, to assess the overall quality of the reports. A low CO-score represents high quality with few or inconsiderate errors.

RESULTS

The results showed no direct connection between high accuracy and low CO-score. All radiographers achieved high levels of accuracy (range: 96.8%-100%) but varied in CO-score (range: 0.00-0.14). One radiographer achieved an accuracy of 97.6% but a high CO-score of 0.14 as four reports had clinical consequence for the patients and five reports lacked minor details. One report was classified as true positive but was inadequate and led to wrong treatment.

CONCLUSION

This study shows that true reports can affect the patients' clinical outcome and reports classified as false can represent insignificant errors. The new CO-score gives a more nuanced view of the reporting quality by including the patients' clinical outcome in the performance score.

IMPLICATIONS FOR PRACTICE

We suggest that the CO-score is included as a supplement to the common methods in future studies assessing the quality of radiology reports as well as in clinical audits.

Galectin-3 is Persistently Increased in Early Rheumatoid Arthritis (RA) and Associates with Anti-CCP Seropositivity and MRI Bone Lesions, While Early Fibrosis Markers Correlate with Disease Activity

Galectin-3 has been suggested as a pro-inflammatory mediator in animal arthritis and rheumatoid arthritis (RA). We aimed to study the serum level of galectin-3 in patients with newly diagnosed RA and associations with disease profile, Magnetic resonance imaging (MRI) findings and seromarkers of synovial matrix inflammation. One hundred and sixty DMARD naïve patients newly diagnosed with RA were included (CIMESTRA study). Clinical, serological and imaging data were recorded before treatment and at 6 weeks, 3 and 12 months. Galectin-3 and hyaluronan (HYA) were measured by ELISA (R&D and Corgenix, USA), and the N-terminal propeptide of type III collagen (PIIINP) by radioimmunoassay (Orion Diagnostica, Finland). One hundred and nineteen, 87 and 60 blood donors served as controls for galectin-3, HYA and PIIINP, respectively. Baseline galectin-3 was significantly elevated in anti-CCP positive (4.2 μg/l IQR [3.6;6.1]) patients as compared with anti-CCP negatives (4.0 μg/l [2.6;4.9], P = 0.05) and controls (3.8 μg/l [3.0;4.8], P < 0.01). During treatment, galectin-3 remained elevated, but increased transiently with peak values at 6 weeks. Galectin-3 correlated with baseline smoking, anti-CCP, and with MRI erosion score after 1 year of follow-up. HYA and PIIINP were elevated (P < 0.001) irrespective of anti-CCP status and correlated positively with synovitis assessed clinically and by MRI. HYA and PIIINP did not correlate with galectin-3. These observations indicate that HYA and PIIINP mainly reflect expansive synovitis proliferation while galectin-3 is more closely linked to autoimmunity, smoking and joint destructive processes.

Cardiac Abnormalities in Adult Patients With Polymyositis or Dermatomyositis as Assessed by Noninvasive Modalities

OBJECTIVE

Cardiac events are a major cause of death in patients with idiopathic inflammatory myopathies. The study objective was in a controlled setting to describe cardiac abnormalities by noninvasive methods in a cohort of patients with polymyositis (PM) or dermatomyositis (DM) and to identify predictors for cardiac dysfunction.

METHODS

In a cross-sectional study, 76 patients with PM/DM and 48 matched healthy controls (HCs) were assessed by serum levels of cardiac troponin I, electrocardiography, Holter monitoring, echocardiography with tissue Doppler imaging, and quantitative cardiac (99m) Tc-pyrophosphate ((99m) Tc-PYP) scintigraphy.

RESULTS

Compared to HCs, patients with PM/DM more frequently had left ventricular diastolic dysfunction (LVDD) (12% versus 0%; P = 0.02) and longer QRS and QT intervals (P = 0.007 and P < 0.0001, respectively). In multivariate analysis, factors associated with LVDD were age (P = 0.001), disease duration (P = 0.004), presence of myositis-specific or -associated autoantibodies (P = 0.05), and high cardiac (99m) Tc-PYP uptake (P = 0.006). In multivariate analysis of the pooled data for patients and HCs, a diagnosis of PM/DM (P < 0.0001) was associated with LVDD.

CONCLUSION

Patients with PM or DM had an increased prevalence of cardiac abnormalities compared to HCs. LVDD was a common occurrence in PM/DM patients and correlated to disease duration. In addition, the association of LVDD with myositis-specific or -associated autoantibodies and high cardiac (99m) Tc-PYP uptake supports the notion of underlying autoimmunity and myocardial inflammation in patients with PM/DM.

Within-day variation and influence of physical exercise on circulating Galectin-3 in patients with rheumatoid arthritis and healthy individuals

Galectin-3 has been suggested as a pro-inflammatory mediator in rheumatoid arthritis (RA). Previous studies have reported overexpression of Galectin-3 in RA synovitis and increased levels in synovial fluid and serum in long-standing RA compared with osteoarthritis and healthy controls. Our objectives were to study whether serum Galectin-3 (1) exhibits circadian variation and/or (2) responds to exercise in RA and controls. The study on circadian patterns (1) comprised eleven patients with newly diagnosed RA, disease duration less than 6 months (ERA), 10 patients with long-standing RA [5-15 years (LRA)] and 16 self-reportedly healthy control subjects. During 24 h, 7 blood samples were drawn at 3-h intervals starting at 10 a.m. through 10 p.m. and at 7 and 10 a.m. on the following day. The study on the effect of physical activity (2) included 10 patients with ERA, 10 with LRA and 14 controls. The participants underwent a standardized exercise programme and four blood samples were drawn before, during and after exercise. Serum Galectin-3 was quantified by ELISA (R&D systems). (1) Galectin-3 was increased at baseline in both RA subsets (P = 0.08). There were no diurnal oscillations (P = 0.85). Day-to-day variation amounted to 3%. (2) Baseline Galectin-3 was increased in LRA versus controls and ERA (P < 0.01 and 0.05). Physical exercise induced 10-15% Galectin-3 increments in RA and controls (P < 0.001) peaking after 1-3 h. To conclude, Galectin-3 did not exhibit circadian variation. Day-to-day variation was 3%. Exercise elicited comparable increments in patients with RA of short and long duration and controls, approaching normal after 1-3 h.

Interactions between smoking, increased serum levels of anti-CCP antibodies, rheumatoid factors, and erosive joint disease in patients with early, untreated rheumatoid arthritis

OBJECTIVES

To determine to what extent shared epitopes, smoking, and anti-cyclic citrullinated peptide (anti-CCP) antibodies are associated with disease activity and erosive disease in patients with rheumatoid arthritis (RA) at disease onset.

METHOD

RA patients not previously treated with disease-modifying anti-rheumatic drugs (DMARDs) and with a disease duration of < 6 months (CIMESTRA study) were examined for shared epitopes, anti-CCP antibodies, immunoglobulin M rheumatoid factor (IgM-RF) and IgA-RF, radiographic erosive changes in hands and feet, and clinical disease activity.

RESULTS

The study comprised 153 patients, of whom 104 (68%) were ever-smokers. The prevalence of patients with 0, 1, or 2 shared epitopes was 40 (48%), 71 (49%), and 33 (23%), respectively. Anti-CCP antibodies, IgM-RF, and IgA-RF were present in 89 (58%), 99 (65%), and 82 (54%) patients, respectively. Among smokers, erosive disease was associated with anti-CCP antibodies [odds ratio (OR) 3.9, 95% confidence interval (CI) 1.6-9.3], IgM-RF (OR 4.9, 95% CI 1.9-12), and IgA-RF (OR 2.8, 95% CI 1.2-6.4) but absent with regard to shared epitopes. Among never-smokers, erosive disease was not associated with either shared epitopes or antibodies. All antibody levels measured were associated with smoking and shared epitopes.

CONCLUSIONS

Shared epitopes and smoking were associated with the production of anti-CCP antibodies and rheumatoid factors of IgM and IgA isotypes, which again were associated with erosive disease at presentation only in smokers. As shared epitopes and smoking were not directly associated with erosive disease, smoking may enhance the development of erosive disease in RA at different levels or through separate pathways.

Differential association of the N-propeptide of collagen IIA (PIIANP) and collagen II C-telopeptide (CTX-II) with synovitis and erosions in early and longstanding rheumatoid arthritis

OBJECTIVES

To determine the N-terminal propeptide of collagen IIA (PIIANP) in early and established rheumatoid arthritis (RA) and to study the association with collagen II degradation assessed by its C-telopeptide (CTX-II), x-ray status and disease activity measures.

METHODS

Two cohorts of RA patients were included: A) a one-year prospective cohort including 45 patients with early, untreated RA and B) a cross-sectional study comprising 50 RA patients with advanced disease. Blood donors and healthy volunteers served as controls. PIIANP in serum and urine CTX-II were measured by ELISA.

RESULTS

PIIANP did not differ from control levels at any time in patients with early RA (p=0.16 and p=0.89), but at one-year follow-up, PIIANP was decreased compared with baseline (p=0.046). In patients with longstanding RA, PIIANP was lower than in controls (p=0.002) and RA patients with a 12-month disease (p=0.01). PIIANP was unrelated to joint counts and CRP in both cohorts, but baseline PIIANP was lower among x-ray progressors than in non-progressors (p=0.04). CTX-II was persistently increased in both cohorts (p<0.001 and p<0.001). CTX-II was positively associated with joint counts and CRP but not with x-ray progression (p=0.84). There was no correlation between PIIANP and CTX-II.

CONCLUSION

Declining PIIANP with increasing RA duration and persistently increased CTX-II indicate that cartilage anabolic and degradative pathways are unbalanced from clinical RA onset. Furthermore, that collagen II depletion in RA is both mediated by anti-anabolic effects unassociated with synovitis (decreased PIIANP) and by excess collagen II degradation linked to synovitis (increased CTX-II).

Three-dimensional endoluminal ultrasound-guided interstitial brachytherapy in patients with anal cancer

BACKGROUND

New techniques using image guidance other than computed tomography (CT) and traditional two-dimensional (2D) endosonography might improve interstitial brachytherapy in patients with anal cancer.

PURPOSE

To investigate a new technique guided by three-dimensional (3D) endosonography used in our institution.

MATERIAL AND METHODS

Seventeen patients with anal carcinoma were referred to interstitial brachytherapy under 3D endosonographic guidance after external radiotherapy. The procedure was initiated by anal endosonography performed with a 10-MHz rotating endoprobe. Cross-sectional images of the anal sphincters were stored on a 3D system during retraction of the endoprobe through the anal canal. Afterward, any projection could be reconstructed. From this scanning, the optimal positioning of the needles was determined. The needles were inserted through holes in an externally fixated anal template. A repeated endosonography assured that optimal tumor coverage could be obtained by adjusting the number, dwell positions, and/or position of the needles.

RESULTS

In all patients, endosonography was able to visualize the extension of the tumors and the position of each needle in 3D.

CONCLUSION

3D endosonography guidance of interstitial brachytherapy in anal carcinoma seems to optimize the implant procedure and offer better information for dose planning.

Detection rate of periintestinal lymph nodes

AIM

Compared to standard two-dimensional (2D) endosonography, three-dimensional (3D) endosonography has been presented as a possible improvement regarding imaging of the gastrointestinal (G-I) tract and detection of metastatic lymph nodes. The aim of this study was to evaluate the efficacy of detecting periintestinal lymph nodes in surgical specimens using 3D endosonography.

PATIENTS AND METHODS

Surgical specimens from 31 patients with malignant G-I tumours were investigated by 3-D endosonography and histology with focus on the presence of periintestinal lymph nodes and presence of metastasis. The specimens were scanned submerged into water. Position and size of the lymph nodes were mapped on a photo of the specimen both by the pathologist and the examiners.

RESULTS

Three-dimensional endosonography detected 48 out of 60 malignant lymph nodes (80.0 %), and 110 out of 219 benign lymph nodes (50.2 %). The positive predictive value for an endosonographic finding interpreted as a lymph node was 0.97.

CONCLUSION

The detection rates for periintestinal lymph nodes were relatively high and seemed superior to the one usually assigned to 2D endosonography. Although distinguishing between metastatic and non-metastatic lymph nodes remains a problem, all patients with histologically confirmed metastasis to lymph nodes were detected by 3D endosonography, and the technique thus seems suitable for grouping of patients prior to surgery.

Patients with schizophrenia treated with aripiprazole, a multicentre naturalistic study

OBJECTIVE

The purpose was to carry out a naturalistic study on efficacy, safety and tolerability of aripiprazole during treatment of schizophrenia. Fifty-one patients with an ICD-10 diagnosis of schizophrenia and partial responders to prior antipsychotic medication were offered treatment with aripiprazole as monotherapy or in combination their prior medication. Inclusion criteria were lack of therapeutic effect or adverse events on former antipsychotic treatment.

METHOD

Six-month open multicentre naturalistic study with prospective assessments including Body Mass Index (BMI), Clinical Global Impression-Severity (CGI-S), Clinical Global Impression-Improvement, Global Assessment of Functioning Scale (GAF) and adverse events.

RESULTS

A statistically significant improvement in the different measures of psychopathology and global functioning (CGI-S reduction 34.7%; GAF improvement 14%) was shown in combination with a statistically significant reduction in BMI of 2.9%. Nine patients (17.6%) did not complete the 6-month treatment.

CONCLUSION

In an open multicentre naturalistic study, aripiprazole showed to improve the severity of psychotic symptoms and the global level of functioning. However, many of the patients (47%) were also given another antipsychotic drug at the same time. Also, high compliance and few side effects were reported. However, because of the study design, the results must be interpreted conservatively.

Three-dimensional anal endosonography may improve diagnostic confidence of detecting damage to the anal sphincter complex

The aim of study was to investigate the differences between three-dimensional (3D) endosonography and two-dimensional (2D) endosonography in visualizing damage to the anal sphincter complex. 33 patients with a history of damage to the anal sphincters were examined with a 10 MHz rotating endoprobe. Cross-sectional images of the anal sphincters were stored on a 3D system during retraction of the endoprobe through the anal canal. Cross-sectional images (2D) were compared with reconstructed projections (3D) according to five parameters relating to damage of different parts of the sphincter muscles as well as scar-tissue formation in the rectovaginal septum. Depending on whether the investigator felt confident in diagnosis of scar tissue being present or not a numerical value of 1 or 0 was assigned. In this way a scale from 0 to 5 points was achieved, which ideally should be identical in 3D and 2D. Overall both observers felt diagnostic confidence in a median of five parameters (range 4-5) using 3D, compared with a median of four parameters (range 3-5) using 2D (p=0.001). When only assessing the four parameters relating to damage of different parts of the sphincter-muscles the observers felt diagnostic confidence in eight more cases using 3D than 2D. This difference did not reach statistical significance. The overall agreement between the two observers comparing all five parameters was 98.2% using 3D and 87.9% using 2D. 3D anal endosonography improves diagnostic confidence in detecting damage to the anal sphincter complex. The agreement between the two observers was acceptable using 2D but better when using 3D. The 3D method may improve the selection of patients for surgical repair of the anal sphincter complex.

Ultrasound-guided drainage of breast abscesses: results in 151 patients

The aim of this paper is to describe the efficacy of ultrasound-guided drainage of breast abscesses with special attention to the risk of recurrence and the need for surgical treatment in a consecutive patient population. 151 patients, 89 with puerperal and 62 with non-puerperal breast abscesses, were treated with ultrasound-guided drainage, by needle or catheter under local anaesthesia. Follow-up punctures were performed at 2 or 3 day intervals until the clinical condition and ultrasound findings had improved. All patients were treated with oral antibiotics. Mammography was performed to search for underlying cancer. 86 (97%) out of 89 patients with puerperal abscesses and 50 (81%) out of 62 with non-puerperal abscesses recovered after the first round of ultrasound-guided drainage. One patient in each group had recurrence in loco but recovered after further ultrasound-guided drainage. 13 patients, 11 with non-puerperal and two with puerperal abscesses, underwent surgical excision of the abscess cavity or fistulas. Breastfeeding continued and 117 patients were treated as outpatients. The median number of follow up examinations in the ultrasound-department was four (range 1-10) for the group of patients with puerperal abscess and three (range 1-7) in the group of patients with non-puerperal abscess. The corresponding figure for the median number of punctures was for both groups one (range 1-6 and 1-4). There were no reports of newly diagnosed breast cancer in the 2 year follow-up period. This study supports the use of ultrasound-guided drainage in puerperal and non-puerperal breast abscesses. The method is less invasive than traditional surgery and has a high rate of success.

Insular lesions, ECG abnormalities, and outcome in acute stroke

It has been suggested that lesions in the insula may result in abnormal electrocardiographic (ECG) findings and increase the risk of sudden death. We investigated if computed tomography (CT) detected insular lesions due to acute stroke were related to ECG abnormalities and mortality at three months. Acute insular lesions were diagnosed in 43/179 patients (left insular = 25; right insular = 17; bilateral = 1) with acute stroke (cerebral infarcts = 62 and intracerebral haemorrhage = 17) based on CT scans from 5-8 days after stroke onset; 12 lead ECGs were recorded on admission and ECG telemetry was done in the first 12-24 hours after admission. Information regarding mortality at three months was obtained. Insular lesions were related to sinus tachycardia with heart rate >120 bpm (p = 0.001), ectopic beats >10% (p = 0.032), and ST elevation (p = 0.011). Right insular lesions were related to atrial fibrillation (p = 0.009), atrioventricular block (p = 0.029), ectopic beats >10% (p = 0.016), and inverted T wave (p = 0.040). Right insular lesions, compared with left or no insular lesions, increased the odds of death within three months (OR 6.2, 95% CI 1.5 to 25.2) independent of stroke severity, lesion volume, and age. As the number of patients in the present study is relatively small, our findings need to be confirmed in studies on other populations of stroke patients.

Anthropometric variation in west-central Mexico

Anthropometric data from five indigenous Mexican groups, collected by Carlos and Manuel Basauri in 1933, were reanalyzed and compared with serological and cranial non-metric data. Ten cranial and 14 postcranial measurements were used, both separately and together. Bias-corrected r0 and FST values were slightly higher for the postcranial analysis (0.033) than for the cranial analysis (0.024). Given the degree of linguistic differentiation among the Mexican populations, not to mention the different histories of the communities sampled, this result is surprisingly low. The two groups which were closest linguistically and geographically, the Cora and Huichol, were also close biologically. The other three groups, Tarascan, Aztecan, and Otomi, were not closely related to each other or to the Cora-Huichol pair. More interesting than the relationship between populations in this case are those within them. The Aztecas of Tuxpan, Jalisco, exhibit high rii values and lower-than-expected phenotypic variance, suggesting the pronounced action of genetic drift. The Otomi of Ixmiquilpan and Cora of the Sierra de Nayarit, despite their very different histories, both exhibit low rii values and higher-than-expected phenotypic variance, indicating a high level of gene flow. Despite the phenotypic similarities between the Cora and Huichol, their residual variance is very different; this mirrors serological investigations of relative admixture. Over all, recent population history, and especially non-indigenous admixture, are at least as explicative of the observed biological variation as historical linguistic ties are.

An isonymic study of the population structure of early Kings County, NY

Isonymy has proven a useful method for studying the genetic structure of historical populations. In the United States, the populations studied have been of predominantly British origin. Many of the early settlers in this country, however, came from different cultural backgrounds, which may have affected their settlement patterns and genetic structure. The first European settlers of Kings County, New York, were Dutch, and Dutch was still spoken there in the 19th century. In the early Colonial period, it was an isolated agricultural area, but it was increasingly drawn into the larger metropolis of New York City, a process that culminated at the end of the 19th century. This paper uses census data from 1698, 1738, 1790, and 1810 to assess synchronic and diachronic isonymy patterns within the county. These censuses subdivide the county into six towns, five founded by the Dutch (Brooklyn, Bushwick, Flatbush, Flatlands, and New Utrecht) and one by the English (Gravesend). All were founded at least a generation before 1698. Values of Iii, FST, and RST increased from 1698 to 1738, a period when Kings County received few immigrants, and decreased thereafter as the influence of the metropolis grew. Most new immigrants settled in Brooklyn, so the lowest levels of isonymy occurred there [Iii (1810) = 0.0029]. The highest levels occurred in Flatlands [Iii (1738) = 0.0838]. FST increased from 0.0050 to 0.0076, and then fell to 0.0052 and 0.0032; RST was approximately two-thirds as high, at 0.0033, 0.0053, 0.0033, and 0.0022. These values are more than twice as high as those reported from 19th-century Massachusetts or Pennsylvania, and are comparable to those found in rural European populations. The towns can be divided into two groups: Brooklyn, Bushwick, and Flatbush, with an average Iii of 0.01570, and Flatlands, Gravesend, and New Utrecht, with an average value of 0.03963. The three latter towns were geographically more distant from New York City and remained more isolated both culturally and biologically.

Population relationships by isonymy in frontier Pennsylvania

Data from the 1800 US census were used to study relationships by isonymy among 7 civil subdivisions of Bedford County, Pennsylvania. Two analyses of the data were conducted. In the first analysis heads of household served as the unit of analysis. In the second analysis the total number of individuals in each household was used to correct for varying family sizes. All measures of internal differentiation were approximately doubled when the complete population numbers were used. The head-of-household analysis produced FST and RST values of 0.0012 and 0.0007, respectively; the complete population analysis yielded 0.0021 for FST and 0.0015 for RST. Interpopulation a priori kinship estimations were similar using both methods. Conditional kinship estimations varied more, with almost all values negative, but the head-of-household estimates were less negative. Multidimensional scaling of isonymy values coincided fairly well with actual geographic relationships, but a Mantel test revealed no significant relationship between geographic distances and isonymy, and isolation by distance values indicated a low relationship between the 2 measures. The population of the county was heterogeneous, with low kinship between its constituent communities. This appears to be a result of kin-structured long-distance migration rather than of local processes. The head-of-household values are more comparable with other studies and more representative of population relationships; complete population values exaggerate heterogeneity because of random fluctuations in household size.

Ethnohistorical evidence for inbreeding among the pre-Hispanic Mixtec royal caste

Pre-Columbian Mixtec social organization was distinguished by the tight endogamy of the ruling class, which included many consanguineous marriages. It was also characterized by a vigorous historical and genealogical tradition. The historical documents, or codices, provide materials for the calculation of the levels of inbreeding present before the Spanish Conquest. A genealogical analysis of inbreeding was performed on the combined pedigree, which spanned the tenth through sixteenth centuries, of all individuals connected by ancestry, descent, or marriage with Lord 8 Deer Jaguar Claw of Tilantongo (A.D. 1063-1115). Sixty of the 217 couples (27.65%) were consanguineous. When only couples of wholly known grandparentage were considered (N = 39), F = 0.1051. The mean F of all couples, even those where one spouse was of unknown parentage, was 0.0243. Over the 550 years of the pedigree the maximum F in any 52-year period was 0.1324. This level of inbreeding is sufficient to produce noticeable effects on population structure and affinities over time.

Odontometric microevolution in the Valley of Oaxaca, Mexico

Tooth crown lengths, breadths, and areas were compared from five sequential human skeletal samples from the Valley of Oaxaca, Mexico, spanning the period from 1600 BC to AD 1521. Almost all of the measurements considered exhibited dramatic reduction over that period. Total crown area declined from 1320 mm2 to 1262 mm2, a change of 4.4% or 9.4 darwins, which is noticeably larger than any previously reported rate of dental reduction in a recent human population. This reduction was greatest in posterior tooth breadths, especially in the mandible. The patterning of the reduction, and of the variance of the measurements, indicates that natural selection was primarily responsible for the change. Of all the measurements, anterior breadths appear to have been the least subject to selection, and posterior lengths the next least. The degree of reduction suggests that selective pressures towards smaller teeth were greater in Mesoamerica than elsewhere. This case provides an example of the value of recent human skeletal series for the study of microevolutionary processes.

Cranial non-metric variation in north and central Mexico

Fifty cranial non-metric traits were scored on twenty series of crania from north and central Mexico in the American Museum of Natural History. Additional crania from three of the series were scored in the Musco Nacional de Antropología. Mexico City. Although a total of 471 crania and 316 mandibles were registered, only 11 series containing 387 crania and 270 mandibles, were of sufficient length for statistical analysis. Trait frequencies in these series were compared by multidimensional scaling and principal component analysis. The results suggest a degree of biological continuity in the Basin of Mexico over a twenty-five hundred year period, although the later samples from that area exhibit signs of some gene flow from more northern populations.