Meiotic prophase arrest with failure of chromosome synapsis in mice deficient for Dmc1, a germline-specific RecA homolog

DMC1 is a meiosis-specific gene first discovered in yeast that encodes a protein with homology to RecA and may be component of recombination nodules. Yeast dmc1 mutants are defective in crossing over and synaptonemal complex (SC) formation, and arrest in late prophase of meiosis I. We have generated a null mutation in the Dmc1 gene in mice and show that homozygous mutant males and females are sterile with arrest of gametogenesis in the first meiotic prophase. Chromosomes in mutant spermatocytes fail to synapse, despite the formation of axial elements that are the precursor to the SC. The strong similarity of phenotypes in Dmc1-deficient mice and yeast suggests that meiotic mechanisms have been highly conserved through evolution.

Untreated blood pressure level is inversely related to cognitive functioning: the Framingham Study

It was hypothesized that blood pressure would be inversely related to cognitive functioning, if unconfounded with antihypertensive medication and measured over many occasions prior to neuropsychological testing. For stroke-free Framingham Study participants aged 55-88 years (n = 1,702), blood pressure levels were averaged over five biennial examinations (1956-1964) when few hypertensives were being treated, and examined in relation to neuropsychological tests administered between 1976 and 1978. With age, education, occupation, cigarette smoking, alcohol consumption, and gender controlled, blood pressure levels and chronicity of hypertension were inversely related to the composite score and measures of attention and memory. This was true for the full sample, for a subsample untreated during blood pressure measurement (n = 1,485), and for a subsample untreated throughout the entire study period (n = 1,038). For example, decline per 10 mmHg increment in blood pressure ranged from -0.04 to -0.07 standard score units (z) for the composite score. A negative finding previously was most likely due to blood pressure measurement concurrently with neuropsychological testing, or too few measurements. Hypertension-associated pathogenic processes may cause mild cognitive impairment, but other mechanisms need to be considered.

Prevalence of dementia and probable senile dementia of the Alzheimer type in the Framingham Study

We determined the prevalence of dementia and probable senile dementia of the Alzheimer type (SDAT) for biennial Exam 17 of the Framingham cohort (1982/1983). The prevalence of dementia was 30.5/1,000 for men and 48.2/1,000 for women and increased with advancing age. Cases of probable SDAT constituted 55.6% of all dementia cases. THe prevalence of SDAT was 11.7/1,000 for men and 30.1/1,000 for women and also increased with advancing age. Prevalence of dementia and probable SDAT were greater for women than men. The female:male ratio of prevalence for cohort members 75 years of age and older was 1.8 for all cases of dementia and 2.8 for cases of probable SDAT.

Cerebrospinal fluid cytology in patients with cancer: minimizing false-negative results

BACKGROUND

Detection of malignant cells on cytologic examination of the cerebrospinal fluid (CSF) is the diagnostic gold standard for leptomeningeal carcinomatosis. The absence of cells is a primary endpoint for most therapeutic trials. Unfortunately, false-negative results are common. Practical strategies are necessary to remedy this problem.

METHODS

Four physician-dependent variables (CSF sample volume, site of CSF sampling, processing time, and frequency of CSF sampling) were identified, and their contributions to the false-negative rate of CSF cytology were evaluated prospectively in 39 patients with leptomeningeal carcinomatosis. Retrospective data were analyzed to estimate the importance of these variables in daily practice.

RESULTS

False-negative CSF cytology results correlated with small CSF volume (P < 0.001), delayed processing (P < 0.001), not obtaining CSF from a site of symptomatic or radiographically demonstrated disease (P = 0.02), and sampling fewer than two times (P < 0.001). In 1 year, 97% of CSF specimens at the study institution were of inadequate volume; >25% were processed too slowly.

CONCLUSIONS

False-negative CSF cytology results are common, but can be minimized by: 1) withdrawing at least 10.5 mL of CSF for cytologic analysis; 2) processing the CSF specimen immediately; 3) obtaining CSF from a site of known leptomeningeal disease; and 4) repeating this procedure once if the initial cytology is negative.

Clomipramine and exposure for obsessive-compulsive rituals: i

Forty chronic obsessive-compulsive ritualizers were randomly assigned to treatment with oral clomipramine or placebo for 8 months. During weeks 4 to 7 these two groups were each randomly split into treatment by relaxation or by exposure in vivo, and during weeks 7 to 10 all patients had exposure in vivo. Double blind assessments were made at weeks 4, 7, 10, 18, 36, 62 and 114. Results are reported to one year. Clomipramine produced significant improvement in rituals, mood and social adjustment, but only in those patients who initially had depressed mood. The clomipramine effect was maximum from weeks 10 to 18 and diminished thereafter. On stopping clomipramine patients often relapsed and improved again on restarting the drug. Relaxation produced little change. Exposure produced significant lasting improvement in rituals, but less change in mood; improvement generalized to social adjustment at follow-up. Clomipramine plus exposure had a slight additive but not interactional effect. Clomipramine enhanced compliance both with exposure and with relaxation. Clomipramine is useful for compulsive ritualizers with depressed mood, but may need continuation for over a year and combination with exposure in vivo. Exposure in vivo remains the treatment of choice for rituals without depressed mood.

Sudden coronary death in women

OBJECTIVES

The objective of this study was to examine prospectively the incidence, predisposing cardiovascular conditions, and risk factors for sudden death in women compared with men.

METHODS AND RESULT

The study design was a prospective general population examination of a cohort of 2873 women for development of sudden coronary death in relation to antecedent overt coronary heart disease (CHD), cardiac failure, and risk factors for coronary heart disease. Participants were women aged 30 to 62 years participating in the Framingham Study, receiving routine biennial examinations for risk factors and cardiovascular conditions. Among women monitored over a period of 38 years, there were 750 initial coronary events, of which 94 (12%) were sudden cardiac deaths. Of the 292 CHD fatalities in women, 32% were sudden cardiac deaths and 37% of the women had a history of prior CHD. Sudden death incidence in women logged behind that in men by >10 years. However, above age 75 years, 17% of all CHD events in women were sudden deaths. Sudden death risk in women with CHD was half as high as in men if they had CHD. In both sexes, a myocardial infarction conferred twice the risk of angina. Cardiac failure escalated sudden death risk of women 5-fold but was only one fourth that of men with failure or CHD. Ventricular ectopy increased sudden death risk only in women without prior overt CHD. Except for diabetes, CHD risk factors imposed a lower sudden death risk in women than men. However, even in women, sudden death risk increased over a 17-fold range in relation to their burden of CHD risk factors.

CONCLUSIONS

Sudden death is a prominent feature of CHD in women as well as men, particularly in advanced age. A higher fraction of sudden deaths in women than men is unexpected occurring in the absence of prior overt CHD. It is subject to the same risk factors and as predictable in women as in men. However, at any level of multivariate risk, women are less vulnerable to sudden death than men.

Alignment options for total knee arthroplasty: A systematic review

In spite of improvements in implant designs and surgical precision, functional outcomes of mechanically aligned total knee arthroplasty (MA TKA) have plateaued. This suggests probable technical intrinsic limitations that few alternate more anatomical recently promoted surgical techniques are trying to solve. This review aims at (1) classifying the different options to frontally align TKA implants, (2) at comparing their safety and efficacy with the one from MA TKAs, therefore answering the following questions: does alternative techniques to position TKA improve functional outcomes of TKA (question 1)? Is there any pathoanatomy not suitable for kinematic implantation of a TKA (question 2)? A systematic review of the existing literature utilizing PubMed and Google Scholar search engines was performed in February 2017. Only studies published in peer-reviewed journals over the last ten years in either English or French were reviewed. We identified 569 reports, of which 13 met our eligibility criteria. Four alternative techniques to position a TKA are challenging the traditional MA technique: anatomic (AA), adjusted mechanical (aMA), kinematic (KA), and restricted kinematic (rKA) alignment techniques. Regarding osteoarthritic patients with slight to mid constitutional knee frontal deformity, the KA technique enables a faster recovery and generally generates higher functional TKA outcomes than the MA technique. Kinematic alignment for TKA is a new attractive technique for TKA at early to mid-term, but need longer follow-up in order to assess its true value. It is probable that some forms of pathoanatomy might affect longer-term clinical outcomes of KA TKA and make the rKA technique or additional surgical corrections (realignment osteotomy, retinacular ligament reconstruction etc.) relevant for this sub-group of patients. Longer follow-up is needed to define the best indication of each alternative surgical technique for TKA. Level I for question 1 (systematic review of Level I studies), level 4 for question 2.

Non-alcoholic steatohepatitis and iron: increased prevalence of mutations of the HFE gene in non-alcoholic steatohepatitis

BACKGROUND/AIMS

Non-alcoholic steatohepatitis (NASH) is increasingly recognized, and its pathogenesis is believed to involve increased oxidative stress. Elevated levels of serum ferritin and positive liver iron stains are often observed in patients with NASH, and the pathogenesis of liver injury due to iron is also thought to involve oxidative stress. The aim of this study was to determine whether there is an association of NASH and mutations in the HFE gene associated with hereditary hemochromatosis (HHC).

METHODS

Clinical, laboratory, and histopathological data on all 57 subjects with a final diagnosis of NASH seen between August 1990 and August 1997 at our Liver Center were analyzed. Thirty-six Caucasian subjects (23 men) with NASH underwent mutational analyses of HFE gene mutations performed. The prevalence of HFE gene mutations was compared to that in 348 Caucasian normal controls. Data were analyzed by both parameteric and non-parametric methods with similar results.

RESULTS

One subject (2.8%) with NASH was homozygous for the C282Y mutation and six (16.7%) were heterozygous, compared with 0%, and 11.2%, respectively, of controls. Two (5.6%) subjects with NASH were homozygous for the H63D mutation and 16 (44.4%) were heterozygous, whereas 2.9% and 26.4%, respectively, of controls had these genotypes. The prevalence of heterozygosity (61.1%) for either mutation was significantly higher in subjects with NASH than in controls (38%) (p = 0.008), and the prevalence of homozygosity or heterozygosity combined in NASH subjects (69.4%) was significantly higher than for controls (40.5%, p = 0.001). Sex (63-67% male) and age at diagnosis of NASH did not differ between those with or without HFE mutations, but men with NASH were significantly more likely than women to have the H63D mutation (15/23 vs. 3/13, p<0.05) Levels of serum ferritin, iron, transferrin saturation levels, and the degree of hepatic iron staining were significantly higher (p<0.05) in subjects with NASH who carried an HFE mutation than in those without. Differences in hepatic iron concentrations or hepatic iron indices between NASH subjects with and without HFE mutations were not significant. Those with C282Y mutations had significantly more hepatic fibrosis than those without (p<0.05). Those with HFE mutations had significantly higher levels of serum ALT (90+/-11 [mean +/- SE]) than those without (55+/-6; p = 0.02).

CONCLUSION

The prevalences of the HFE gene mutations associated with hereditary hemochromatosis are increased among North American subjects with NASH.

Number of pregnancies and the subsequent risk of cardiovascular disease

BACKGROUND

Whether increasing parity or gravidity is a risk factor for coronary heart disease has been debated, but the question remains unresolved.

METHODS

We tested the association between the number of pregnancies and a variety of cardiovascular end points in two groups of women who had completed childbearing. One group comprised 2357 women who were followed for 28 years through the Framingham Heart Study, and the other 2533 women followed for at least 12 years through the first National Health and Nutrition Examination Survey National Epidemiologic Follow-up Study (NHEFS).

RESULTS

The rates of coronary heart disease were higher among multigravid women than among women who had never been pregnant, in both the Framingham Heart Study and the NHEFS, but in both studies, the higher rates were statistically significant only in women with six or more pregnancies. For the women in the Framingham Study, the rate ratio adjusted for age and educational level in the group with six or more pregnancies (as compared with women who had never been pregnant) was 1.6 (95 percent confidence interval, 1.1 to 2.2). For the women in the NHEFS, the same adjusted rate ratio was 1.5 (95 percent confidence interval, 1.1 to 1.9). Adjustments for other known cardiovascular risk factors, including weight, did not markedly alter this risk. The rate of total cardiovascular disease was also significantly higher among multigravid women in the Framingham Study than in the women who had never been pregnant.

CONCLUSIONS

In two prospective American studies, having six or more pregnancies was associated with a small but consistent increase in the risk of coronary heart disease and cardiovascular disease. Whether gravidity itself or some other unmeasured factor accounts for the increase in risk that we observed requires further investigation.

Hands-on robotic unicompartmental knee replacement: a prospective, randomised controlled study of the acrobot system

We performed a prospective, randomised controlled trial of unicompartmental knee arthroplasty comparing the performance of the Acrobot system with conventional surgery. A total of 27 patients (28 knees) awaiting unicompartmental knee arthroplasty were randomly allocated to have the operation performed conventionally or with the assistance of the Acrobot. The primary outcome measurement was the angle of tibiofemoral alignment in the coronal plane, measured by CT. Other secondary parameters were evaluated and are reported. All of the Acrobot group had tibiofemoral alignment in the coronal plane within 2 degrees of the planned position, while only 40% of the conventional group achieved this level of accuracy. While the operations took longer, no adverse effects were noted, and there was a trend towards improvement in performance with increasing accuracy based on the Western Ontario and McMaster Universities Osteoarthritis Index and American Knee Society scores at six weeks and three months. The Acrobot device allows the surgeon to reproduce a pre-operative plan more reliably than is possible using conventional techniques which may have clinical advantages.

The painful metal-on-metal hip resurfacing

We carried out metal artefact-reduction MRI, three-dimensional CT measurement of the position of the component and inductively-coupled plasma mass spectrometry analysis of cobalt and chromium levels in whole blood on 26 patients with unexplained pain following metal-on-metal resurfacing arthroplasty. MRI showed periprosthetic lesions around 16 hips, with 14 collections of fluid and two soft-tissue masses. The lesions were seen in both men and women and in symptomatic and asymptomatic hips. Using three-dimensional CT, the median inclination of the acetabular component was found to be 55 degrees and its positioning was outside the Lewinnek safe zone in 13 of 16 cases. Using inductively-coupled plasma mass spectrometry, the levels of blood metal ions tended to be higher in painful compared with well-functioning metal-on-metal hips. These three clinically useful investigations can help to determine the cause of failure of the implant, predict the need for future revision and aid the choice of revision prostheses.

The Global Economic Cost of Osteoarthritis: How the UK Compares

Aims. To examine all relevant literature on the economic costs of osteoarthritis in the UK, and to compare such costs globally. Methods. A search of MEDLINE was performed. The search was expanded beyond peer-reviewed journals into publications by the department of health, national orthopaedic associations, national authorities and registries, and arthritis charities. Results. No UK studies were identified in the literature search. 3 European, 6 North American, and 2 Asian studies were reviewed. Significant variation in direct and indirect costs were seen in these studies. Costs for topical and oral NSAIDs were estimated to be £19.2 million and £25.65 million, respectively. Cost of hip and knee replacements was estimated to exceed £850 million, arthroscopic surgery for osteoarthritis was estimated to be £1.34 million. Indirect costs from OA caused a loss of economic production over £3.2 billion, £43 million was spent on community services and £215 million on social services for osteoarthritis. Conclusions. While estimates of economic costs can be made using information from non-published data, there remains a lack of original research looking at the direct or indirect costs of osteoarthritis in the UK. Differing methodology in calculating costs from overseas studies makes direct comparison with the UK difficult.

The influence of spine-hip relations on total hip replacement: A systematic review

Sagittal pelvic kinematics along with spino-pelvic angular parameters have recently been studied by numerous investigators for their effect on total hip replacement (THR) clinical outcomes, but many issue of spine-hip relations (SHR) are currently unexplored. Therefore, our review aims at clarifying the following questions: is there any evidence of a relationship between articular impingement/dislocation risk in primary THR and (1) certain sagittal pelvic kinematics patterns, (2) pelvic incidence, and (3) types of SHRs? A systematic review of the existing literature utilising PubMed and Google search engines was performed in January 2017. Only clinical or computational studies published in peer-reviewed journals over the last five years in either English or French were reviewed. We identified 769 reports, of which 12 met our eligibility criteria. A review of literature shows that sagittal pelvic kinematics, but not the pelvic incidence, influences the risk of prosthetic impingement/dislocation. We found no study having assessed the relationship between this risk and the types of SHRs. Sagittal pelvic kinematics is highly variable among individuals and certain kinematic patterns substantially influences the risk of prosthetic impingement/dislocation. Recommendations for cup positioning are therefore switching from a systematic to a patient-specific approach, with the standing cup orientation Lewinneck safe zone progressively giving way to a new parameter of interest: the functional orientation of the cup. Based on a recently published classification for SHRs, We propose a new concept of "kinematically aligned THR" for the purposes of THR planning. Further studies are needed to investigate the relevance of such a classification towards the assumptions and hypothesis we have made. Level of evidence,- Level IV, systematic review of level III and IV studies.

Evidence for meiotic spindle checkpoint from analysis of spermatocytes from Robertsonian-chromosome heterozygous mice

Mice heterozygous for Robertsonian centric fusion chromosomal translocations frequently produce aneuploid sperm. In this study RBJ/Dn× C57BL/6J F1 males, heterozygous for four Robertsonian translocations (2N=36), were analyzed to determine effects on germ cells of error during meiosis. Analysis of sperm by three color fluorescence in situ hybridization revealed significantly elevated aneuploidy, thus validating Robertsonian heterozygous mice as a model for production of chromosomally abnormal gametes. Primary spermatocytes from heterozygous males exhibited abnormalities of chromosome pairing in meiotic prophase and metaphase. In spite of prophase abnormalities, the prophase/metaphase transition occurred. However, an increased frequency of cells with misaligned condensed chromosomes was observed. Cytological analysis of both young and adult heterozygous mice revealed increased apoptosis in spermatocytes during meiotic metaphase I. Metaphase spermatocytes with misaligned chromosomes accounted for a significant proportion of the apoptotic spermatocytes, suggesting that a checkpoint process identifies aberrant meioses. Immunofluorescence staining revealed that kinetochores of chromosomes that failed to align on the spindle stained more intensely for kinetochore antigens CENP-E and CENP-F than did aligned chromosomes. Taken together, these observations are consistent with detection of malattached chromosomes by a meiotic spindle checkpoint mechanism that monitors attachment and/or congression of homologous chromosome pairs. However, the relatively high frequency of gametic aneuploidy suggests that the checkpoint mechanism does not efficiently eliminate all germ cells with chromosomal abnormalities.

Meiotic events at the centromeric heterochromatin: histone H3 phosphorylation, topoisomerase II alpha localization and chromosome condensation

Mechanisms of chromosome condensation and segregation during the first meiotic division are not well understood. Resolution of recombination events to form chiasmata is important, for it is chiasmata that hold homologous chromosomes together for their oppositional orientation on the meiotic metaphase spindle, thus ensuring their accurate segregation during anaphase I. Events at the centromere are also important in bringing about proper attachment to the spindle apparatus. This study was designed to correlate the presence and activity of two proteins at the centromeric heterochromatin, topoisomerase II alpha (TOP2A) and histone H3, with the processes of chromosome condensation and individualization of chiasmate bivalents in murine spermatocytes. We tested the hypothesis that phosphorylation of histone H3 is a key event instigating localization of TOP2A to the centromeric heterochromatin and condensation of chromosomes as spermatocytes exit prophase and progress to metaphase. Activity of topoisomerase II is required for condensation of chromatin at the end of meiotic prophase. Histone H3 becomes phosphorylated at the end of prophase, beginning with its phosphorylation at the centromeric heterochromatin in the diplotene stage. However, it cannot be involved in localization of TOP2A, since TOP2A is localized to the centromeric heterochromatin throughout most of meiotic prophase. This observation suggests a meiotic function for TOP2A in addition to its role in chromatin condensation. The use of kinase inhibitors demonstrates that phosphorylation of histone H3 can be uncoupled from meiotic chromosome condensation; therefore other proteins, such as those constituting metaphase-promoting factor, must be involved. These results define the timing of important meiotic events at the centromeric heterochromatin and provide insight into mechanisms of chromosome condensation for meiotic metaphase.

Left ventricular hypertrophy and mortality--results from the Framingham Study

Data on the prognostic implications of left ventricular hypertrophy (LVH) in the Framingham Study based on routine ECG, echocardiogram (ECHO) and X-ray determination with 36 years of follow-up indicate that LVH has emerged as a powerful indicator of rapidly evolving lethal atherosclerotic disease, whether determined by ECG, ECHO or X-ray. Cardiovascular morbidity and mortality increase progressively with left ventricular muscle mass from lowest to highest values. The ECG and X-ray versions of LVH each independently contribute to the risk of cardiovascular events; each adds to the risk associated with the other, and those with both are at greater risk than those with either alone. Risk ratios associated with ECG-LVH are substantial and are greatest for cardiac failure and stroke, but coronary disease is the commonest and most lethal sequela. LVH is reversible, the anatomical variety more so than ECG-LVH, and reversal of this toward normal appears to confer greater benefit for the anatomical rather than the ECG manifestation of LVH. The risk of cardiovascular disease associated with LVH is not uniform, varying widely depending not only on whether there is concomitant ECG and anatomical evidence of hypertrophy but also on the associated hypertension, glucose intolerance, lipid profile and cigarette smoking habit. This suggests that there is much to be gained in correcting those associated risk factors which also promote the development of LVH.

Acquisition of competence to condense metaphase I chromosomes during spermatogenesis

Little is known about the timing of meiotic prophase events during spermatogenesis in the mouse or how these events are related to cell-cycle progression. This work was designed to test hypotheses about the timing and biochemical correlates of developmental acquisition of competence to condense bivalent pairs of homologous chromosomes held together by chiasmata. The experimental approach takes advantage of the fact that okadaic acid (OA) treatment of pachytene spermatocytes causes precocious entry into metaphase I (MI) of meiosis. Leptotene and zygotene (L/Z) spermatocytes are not competent to respond to OA with condensation of chiasmate bivalent chromosomes. Competence for MI condensation of chiasmate bivalents is acquired by the middle of the pachytene stage of meiotic prophase, several days after homologous chromosomes become fully synapsed. The acquisition of MI competence is paralleled by the accumulation of histone H1t in the nuclei of mid-pachytene spermatocytes. Biochemical differences also exist between the incompetent L/Z spermatocytes and the competent pachytene spermatocytes. Both have the molecular components of metaphase promoting factor, CDC2 and CYCLIN B1; however, the histone H1 kinase activity of metaphase promoting factor of incompetent L/Z spermatocytes is not activated by OA, as it is in competent pachytene spermatocytes. Additionally, the CDC25C protein phosphatase is present in competent pachytene spermatocytes, but not in incompetent L/Z or early pachytene spermatocytes. Both incompetent and competent spermatocytes accumulate MPM-2 phosphoepitopes and phosphorylated histone H3 in response to OA treatment, indicating that presence of these antigens is not sufficient to promote condensation of meiotic chromosomes. These data demonstrate that meiotic competence of spermatocytes is acquired after homologous chromosome pairing is established and is coincident with first appearance of histone H1t and CDC25C protein phosphatase in spermatocytes.

The compartmental distribution of knee osteoarthritis - a systematic review and meta-analysis

OBJECTIVES

For a population with knee osteoarthritis (OA), determine: 1) the prevalence of single compartmental, bicompartmental and tricompartmental OA, 2) the prevalence of isolated medial tibiofemoral, lateral tibiofemoral, or patellofemoral OA, and combinations thereof.

METHODS

PubMed and Web of Science databases, and reference lists of identified studies, were searched to find studies which reported on the compartmental distribution and prevalence of knee OA. Two independent reviewers assessed studies against pre-defined inclusion criteria and prevalence data were extracted along with subject characteristics. The methodological quality of each included study was assessed. A random-effects model meta-analysis was performed for each OA category to estimate the relative prevalence of OA in the knee compartments amongst people with knee OA.

RESULTS

16 studies (3,786 knees) met the inclusion criteria. High heterogeneity was measured. Normalised for knees with OA, estimated prevalence rates (95% CI) were: single compartmental 50% (31.5-58.3%), bicompartmental 33% (23.1-37.2%) and tricompartmental only 17% (8.8-24.8%). Isolated medial tibiofemoral OA, isolated patellofemoral OA, and combined medial tibiofemoral and patellofemoral OA were more common than tricompartmental disease, occurring in 27% (15.2-31.1%), 18% (9.9-22.7%) and 23% (14.1-27.3%) of people respectively. Single/bicompartmental patterns of disease involving the lateral tibiofemoral compartment were less common, summing to 15% (8.5-18.7%).

CONCLUSION

Three-quarters of people with knee OA do not have tricompartmental disease. This is not reflected in the frequency with which partial and combined partial knee arthroplasties are currently used.

TRIAL REGISTRATION NUMBER

PROSPERO systematic review protocol (CRD42019140345).

Benefits and adverse effects of weight loss. Observations from the Framingham Study

OBJECTIVE

To identify the benefits and adverse effects of weight loss.

DESIGN

Longitudinal, epidemiologic study in a defined population.

PARTICIPANTS

Men and women (n = 2500) who were between 35 and 54 years old at baseline, followed for 20 years in Framingham, Massachusetts.

MEASUREMENTS

Height, weight, lipid levels, blood pressure, smoking status, diet, physical activity, prevalent and incident cardiovascular disease, diabetes, other diseases, and mortality rate were assessed.

RESULTS

Compared with those whose body mass index (BMI) or weight changed least, men and women who lost weight during a 10-year period were older, heavier, and had higher blood pressures and cholesterol levels initially but had the smallest gains in blood pressure and cholesterol levels. However, rates of cigarette smoking were higher, and rates of smoking cessation were lower. During 20 years of further follow-up, death rates were highest in those whose BMI decreased and in those with the highest BMI at study entry. Relative risks for death from cardiovascular disease, coronary heart disease, and all causes were significantly greater by 33% to 61% in men whose BMI decreased after adjusting for age and risk factors for cardiovascular disease. In women, weight loss and weight gain were associated with higher relative risks for cardiovascular disease and coronary heart disease, but only the 38% increase in total mortality rate among women who lost weight was statistically significant after adjusting for age.

CONCLUSIONS

Weight loss was associated with improvements in blood pressure and cholesterol levels but also with continued cigarette smoking, prevalent and incident cardiovascular disease, diabetes mellitus, other diseases, and higher death rates. Leanness and maintenance of stable weight were beneficial to risk factors, and to the prevention of morbidity, and death.

The relationship between the angle of version and rate of wear of retrieved metal-on-metal resurfacings: a prospective, CT-based study

We measured the orientation of the acetabular and femoral components in 45 patients (33 men, 12 women) with a mean age of 53.4 years (30 to 74) who had undergone revision of metal-on-metal hip resurfacings. Three-dimensional CT was used to measure the inclination and version of the acetabular component, femoral version and the horizontal femoral offset, and the linear wear of the removed acetabular components was measured using a roundness machine. We found that acetabular version and combined version of the acetabular and femoral components were weakly positively correlated with the rate of wear. The acetabular inclination angle was strongly positively correlated with the rate of wear. Femoral version was weakly negatively correlated with the rate of wear. Application of a threshold of > 5 μm/year for the rate of wear in order to separate the revisions into low or high wearing groups showed that more high wearing components were implanted outside Lewinnek's safe zone, but that this was mainly due to the inclination of the acetabular component, which was the only parameter that significantly differed between the groups. We were unable to show that excess version of the acetabular component alone or combined with femoral version was associated with an increase in the rate of wear based on our assessment of version using CT.

Cranial neural crest cells contribute to connective tissue in cranial muscles in the anuran amphibian, Bombina orientalis

The contribution of cranial neural crest cells to the development and patterning of cranial muscles in amphibians was investigated in the phylogenetically basal and morphologically generalized frog, Bombina orientalis. Experimental methods included fluorescent marking of premigratory cranial neural crest and extirpation of individual migratory streams. Neural crest cells contributed to the connective tissue component, but not the myofibers, of many larval muscles within the first two branchial arches (mandibular and hyoid), and complex changes in muscle patterning followed neural crest extirpation. Connective tissue components of individual muscles of either arch originate from the particular crest migratory stream that is associated with that arch, and this relationship is maintained regardless of the segmental identity-or embryonic derivation-of associated skeletal components. These developmental relations define a pattern of segmentation in the head of larval anurans that is similar to that previously described in the domestic chicken, the only vertebrate that has been thoroughly investigated in this respect. The fundamental role of the neural crest in patterning skeleton and musculature may represent a primitive feature of cranial development in vertebrates. Moreover, the corresponding developmental processes and cell fates appear to be conserved even when major evolutionary innovations-such as the novel cartilages and muscles of anuran larvae-result in major differences in cranial form.

Analysis of expression and function of topoisomerase I and II during meiosis in male mice

Topoisomerases are nuclear enzymes that remove torsional stress in DNA. Their function is important for replication, transcription, chromosome condensation, and chromosome segregation during mitosis and meiosis. The goal of this work is to analyze both expression and function of topoisomerases during the meiotic stages of mammalian spermatogenesis. The patterns of expression of topoisomerase I and topoisomerase II alpha genes were followed on Northern blots of RNA from testes of mice of different ages and from specific germ cell populations. The transcript of the topoisomerase I gene was highest in somatic cells of the testis and in the mitotically proliferating spermatogonia and meiotic prophase spermatocytes, with the level of transcript decreasing dramatically in postmeiotic spermatids. In contrast, the levels of topoisomerase II alpha transcript were negligible in germ-cell free testes and highest in late meiotic prophase cells and round spermatids. Enzyme activity for both topoisomerase I and topoisomerase II was detected in both pachytene spermatocytes and in round spermatids; topoisomerase II exhibited a higher level of activity in meiotic spermatocytes than in round spermatids. In cultured cells, camptothecin, an inhibitor of topoisomerase I, caused some abnormalities of paired meiotic homologs, but did not inhibit the transition to metaphase. In contrast, teniposide and ICRF-193, inhibitors of topoisomerase II, dramatically inhibited the formation of metaphase chromosomes in cells induced to progress from prophase to metaphase. However, the disassembly of the synaptonemal complex was not inhibited, indicating that this process could be uncoupled from condensation of chromatin to form chromosomes. These studies constitute evidence for a functional requirement for topoisomerase II activity in the transition from meiotic prophase to meiotic metaphase I in mammalian spermatocytes.

Fine-mapping the MHC locus in juvenile idiopathic arthritis (JIA) reveals genetic heterogeneity corresponding to distinct adult inflammatory arthritic diseases

OBJECTIVES

Juvenile idiopathic arthritis (JIA) is a heterogeneous group of diseases, comprising seven categories. Genetic data could potentially be used to help redefine JIA categories and improve the current classification system. The human leucocyte antigen (HLA) region is strongly associated with JIA. Fine-mapping of the region was performed to look for similarities and differences in HLA associations between the JIA categories and define correspondences with adult inflammatory arthritides.

METHODS

Dense genotype data from the HLA region, from the Immunochip array for 5043 JIA cases and 14 390 controls, were used to impute single-nucleotide polymorphisms, HLA classical alleles and amino acids. Bivariate analysis was performed to investigate genetic correlation between the JIA categories. Conditional analysis was used to identify additional effects within the region. Comparison of the findings with those in adult inflammatory arthritic diseases was performed.

RESULTS

We identified category-specific associations and have demonstrated for the first time that rheumatoid factor (RF)-negative polyarticular JIA and oligoarticular JIA are genetically similar in their HLA associations. We also observe that each JIA category potentially has an adult counterpart. The RF-positive polyarthritis association at HLA-DRB1 amino acid at position 13 mirrors the association in adult seropositive rheumatoid arthritis (RA). Interestingly, the combined oligoarthritis and RF-negative polyarthritis dataset shares the same association with adult seronegative RA.

CONCLUSIONS

The findings suggest the value of using genetic data in helping to classify the categories of this heterogeneous disease. Mapping JIA categories to adult counterparts could enable shared knowledge of disease pathogenesis and aetiology and facilitate transition from paediatric to adult services.