Author Correction: Improving gait classification in horses by using inertial measurement unit (IMU) generated data and machine learning

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Exploring the genetics underpinning dynamic laryngeal collapse associated with poll flexion in Norwegian-Swedish Coldblooded Trotter racehorses

BACKGROUND

Dynamic laryngeal collapse (DLC) associated with poll flexion is the most common disorder of the upper respiratory tract (URT) in the Norwegian-Swedish Coldblooded Trotter (NSCT). The disorder, which has also been diagnosed in other breeds of trotters and gaited horses, appears to be related to anatomic phenotypes and only occurs during poll flexion when the horse is exercised 'on the bit'.

OBJECTIVES

Identify genomic regions associated with DLC in the NSCT by combining a rigorous phenotyping protocol with genomic data from a high-density equine genotyping array.

STUDY DESIGN

Prospective case/control study.

METHODS

High-speed treadmill endoscopy was used to phenotype horses (n = 61) for DLC, distinguishing between cases and controls. Genome-wide association (GWA) analysis of DLC status was then performed using a principal component approach (PCA) with haplotype analyses subsequently performed for regions containing single-nucleotide polymorphisms (SNPs) above the suggestive genome-wide significance (GWS) threshold (P<1.0 × 10^-5 ).

RESULTS

One region containing 10 SNPs (Equus caballus chromosome [ECA] 7: 89,601,935-94,647,192) was above the suggestive GWS threshold. Two inferred haplotypes in this region demonstrated significant differences (P<0.001) between cases and controls, with the most frequent haplotype resulting in a significantly increased risk of DLC.

MAIN LIMITATIONS

Small sample size as a result of stringent phenotyping protocols.

CONCLUSIONS

The current study highlights a candidate genomic region on ECA7 as potentially important with regard to the manifestation of DLC. Further exploration of this region and the genes included within it will bring veterinarians and researchers closer to fully understanding the biological mechanisms underlying DLC in horses.

Asian horses deepen the MSY phylogeny

Humans have shaped the population history of the horse ever since domestication about 5500 years ago. Comparative analyses of the Y chromosome can illuminate the paternal origin of modern horse breeds. This may also reveal different breeding strategies that led to the formation of extant breeds. Recently, a horse Y-chromosomal phylogeny of modern horses based on 1.46 Mb of the male-specific Y (MSY) was generated. We extended this dataset with 52 samples from five European, two American and seven Asian breeds. As in the previous study, almost all modern European horses fall into a crown group, connected via a few autochthonous Northern European lineages to the outgroup, the Przewalski's Horse. In total, we now distinguish 42 MSY haplotypes determined by 158 variants within domestic horses. Asian horses show much higher diversity than previously found in European breeds. The Asian breeds also introduce a deep split to the phylogeny, preliminarily dated to 5527 ± 872 years. We conclude that the deep splitting Asian Y haplotypes are remnants of a far more diverse ancient horse population, whose haplotypes were lost in other lineages.

To pace or not to pace: a pilot study of four- and five-gaited Icelandic horses homozygous for the DMRT3 'Gait Keeper' mutation

The Icelandic horse is a breed known mainly for its ability to perform the ambling four-beat gait 'tölt' and the lateral two-beat gait pace. The natural ability of the breed to perform these alternative gaits is highly desired by breeders. Therefore, the discovery that a nonsense mutation (C>A) in the DMRT3 gene was the main genetic factor for horses' ability to perform gaits in addition to walk, trot and canter was of great interest. Although several studies have demonstrated that homozygosity for the DMRT3 mutation is important for the ability to pace, only about 70% of the homozygous mutant (AA) Icelandic horses are reported to pace. The aim of the study was to genetically compare four- and five-gaited (i.e. horses with and without the ability to pace) AA Icelandic horses by performing a genome-wide association (GWA) analysis. All horses (n = 55) were genotyped on the 670K Axiom Equine Genotyping Array, and a GWA analysis was performed using the genabel package in r. No SNP demonstrated genome-wide significance, implying that the ability to pace goes beyond the presence of a single gene variant. Despite its limitations, the current study provides additional information regarding the genetic complexity of pacing ability in horses. However, to fully understand the genetic differences between four- and five-gaited AA horses, additional studies with larger sample materials and consistent phenotyping are needed.

Slope distribution in front-back asymmetric stochastic Lagrange time waves

The stochastic Lagrange wave model is a realistic alternative to the Gaussian linear wave model, which has been successfully used in ocean engineering for more than half a century. In this paper we present the slope distributions and other characteristic distributions at level crossings for asymmetric Lagrange time waves, i.e. what can be observed at a fixed measuring station, thereby extending results previously given for space waves. The distributions are given as expectations in a multivariate normal distribution, and they have to be evaluated by simulation or numerical integration. Interesting characteristic variables are the slope in time, the slope in space, and the vertical particle velocity when the waves are observed close to instances when the water level crosses a predetermined level. The theory has been made possible by recent generalizations of Rice's formula for the expected number of marked crossings in random fields.

The DMRT3 'Gait keeper' mutation affects performance of Nordic and Standardbred trotters

In a previous study it was shown that a nonsense mutation in the DMRT3 gene alters the pattern of locomotion in horses and that this mutation has a strong positive impact on trotting performance of Standardbreds. One aim of this study was to test if racing performance and trotting technique in the Nordic (Coldblood) trotters are also influenced by the DMRT3 genotype. Another aim was to further investigate the effect of the mutation on performance in Standardbreds, by using a within-family analysis and genotype-phenotype correlations in a larger horse material than in the previous study. We genotyped 427 Nordic trotters and 621 Standardbreds for the DMRT3 nonsense mutation and a SNP in strong linkage disequilibrium with it. In Nordic trotters, we show that horses homozygous for the DMRT3 mutation (A) had significantly higher EBV for trotting performance traits than heterozygous (CA) or homozygous wild-type (CC) horses (P = 0.001). Furthermore, AA homozygotes had a higher proportion of victories and top 3 placings than horses heterozygous or homozygous wild-type, when analyzing performance data for the period 3 to 6 yr of age (P = 0.06 and P = 0.05, respectively). Another finding in the Nordic trotters was that the DMRT3 mutation influenced trotting technique (P = 2.1 × 10(-8)). Standardbred horses homozygous AA had significantly higher EBV for all traits than horses with at least 1 wild-type allele (CA and CC; P = 1.6 × 10(-16)). In a within-family analysis of Standardbreds, we found significant differences in several traits (e.g., earnings, P = 0.002; number of entered races, P = 0.004; and fraction of offspring that entered races, P = 0.002) among paternal half-sibs with genotype AA or CA sired by a CA stallion. For most traits, we found significant differences at young ages. For Nordic trotters, most of the results were significant at 3 yr of age but not for the older ages, and for the Standardbreds most of the results for the ages 3 to 5 were significant. For Nordic trotters, the proportion of victories and placings were the only traits that were significant for other ages than 3 yr.

Worldwide frequency distribution of the 'Gait keeper' mutation in the DMRT3 gene

For centuries, domestic horses have represented an important means of transport and served as working and companion animals. Although their role in transportation is less important today, many horse breeds are still subject to intense selection based on their pattern of locomotion. A striking example of such a selected trait is the ability of a horse to perform additional gaits other than the common walk, trot and gallop. Those could be four-beat ambling gaits, which are particularly smooth and comfortable for the rider, or pace, used mainly in racing. Gaited horse breeds occur around the globe, suggesting that gaitedness is an old trait, selected for in many breeds. A recent study discovered that a nonsense mutation in DMRT3 has a major impact on gaitedness in horses and is present at a high frequency in gaited breeds and in horses bred for harness racing. Here, we report a study of the worldwide distribution of this mutation. We genotyped 4396 horses representing 141 horse breeds for the DMRT3 stop mutation. More than half (2749) of these horses also were genotyped for a SNP situated 32 kb upstream of the DMRT3 nonsense mutation because these two SNPs are in very strong linkage disequilibrium. We show that the DMRT3 mutation is present in 68 of the 141 genotyped horse breeds at a frequency ranging from 1% to 100%. We also show that the mutation is not limited to a geographical area, but is found worldwide. The breeds with a high frequency of the stop mutation (>50%) are either classified as gaited or bred for harness racing.

Mixed virtual reality simulation--taking endoscopic simulation one step further

This pilot study aimed to assess medical students' appraisals of a "mixed" virtual reality simulation for endoscopic surgery (with a virtual patient case in addition to a virtual colonoscopy) as well as the impact of this simulation set-up on students' performance. Findings indicate that virtual patients can enhance contextualization of simulated endoscopy and thus facilitate an authentic learning environment, which is important in order to increase motivation.

Genome sequence, comparative analysis, and population genetics of the domestic horse

We report a high-quality draft sequence of the genome of the horse (Equus caballus). The genome is relatively repetitive but has little segmental duplication. Chromosomes appear to have undergone few historical rearrangements: 53% of equine chromosomes show conserved synteny to a single human chromosome. Equine chromosome 11 is shown to have an evolutionary new centromere devoid of centromeric satellite DNA, suggesting that centromeric function may arise before satellite repeat accumulation. Linkage disequilibrium, showing the influences of early domestication of large herds of female horses, is intermediate in length between dog and human, and there is long-range haplotype sharing among breeds.

International Equine Gene Mapping Workshop Report: a comprehensive linkage map constructed with data from new markers and by merging four mapping resources

A comprehensive male linkage map was generated by adding 359 new, informative microsatellites to the International Equine Gene Map half-sibling reference families and by combining genotype data from three independent mapping resources: a full sibling family created at the Animal Health Trust in Newmarket, United Kingdom, eight half-sibling families from Sweden and two half-sibling families from the University of California, Davis. Because the combined data were derived primarily from half-sibling families, only autosomal markers were analyzed. The map was constructed from a total of 766 markers distributed on the 31 equine chromosomes. It has a higher marker density than that of previously reported maps, with 626 markers linearly ordered and 140 other markers assigned to a chromosomal region. Fifty-nine markers (7%) failed to meet the criteria for statistical evidence of linkage and remain unassigned. The map spans 3,740 cM with an average distance of 6.3 cM between markers. Fifty-five percent of the intervals are < or = 5 cM and only 3% > or = 20 cM. The present map demonstrates the cohesiveness of the different data sets and provides a single resource for genome scan analyses and integration with the radiation hybrid map.

Individuals with an increased risk of colorectal cancer: perceived benefits and psychological aspects of surveillance by means of regular colonoscopies

PURPOSE

To evaluate the psychological consequences of genetic counseling followed by a surveillance program using colonoscopy among individuals with increased risk of colorectal cancer.

PATIENTS AND METHODS

Two hundred sixty-five individuals, participating in a surveillance program with colonoscopy, were mailed a survey questionnaire that assessed their experience of the surveillance program and their perception of the risk of colorectal cancer. The Hospital Anxiety and Depression scale and the Swedish Short Form-36 Health Survey was also included.

RESULTS

Two hundred forty individuals completed the questionnaire and were divided into the following risk groups: risk group 1, an individual with a mutation in hMLH1 or hMSH2 and a lifetime colorectal cancer risk of 80% (n = 28); risk group 2, a lifetime colorectal cancer risk of 40% (n = 129); and risk group 3, a lifetime colorectal cancer risk of 20% (n = 83). Among all individuals, the mean for perceived benefit was 8.0, and the perception of discomfort was 3.3 on the visual analog scale (1-10). In risk group 1, 61% underestimated personal risks as being 40% or less. Approximately 50% of the subjects in risk groups 2 and 3 either under- or overestimated their lifetime risk. According to the Swedish Short Form-36 Health Survey and the Hospital Anxiety and Depression scale, the study sample resembled the reference population.

CONCLUSION

A majority of the study sample understood why they were under surveillance, and regular colonoscopies were well-tolerated. The wide range of risk perception as well as low-risk perception in mutation positive subjects is acceptable, as long as these individuals adhere to surveillance programs and do not demonstrate increased levels of anxiety or depression.

The second generation of the International Equine Gene Mapping Workshop half-sibling linkage map

A low-density, male-based linkage map was constructed as one of the objectives of the International Equine Gene Mapping Workshop. Here we report the second generation map based on testing 503 half-sibling offspring from 13 sire families for 344 informative markers using the CRIMAP program. The multipoint linkage analysis localized 310 markers (90%) with 257 markers being linearly ordered. The map included 34 linkage groups representing all 31 autosomes and spanning 2262 cM with an average interval between loci of 10.1 cM. This map is a milestone in that it is the first map with linkage groups assigned to each of the 31 automosomes and a single linkage group to all but three chromosomes.

Adenoma prevalence and cancer risk in familial non-polyposis colorectal cancer

BACKGROUND AND AIMS

Polypectomy in the colon has been shown to prevent colorectal cancer in both the general population and in familial colorectal cancer. Individuals with a family history of colorectal cancer have an increased risk of the disease. Over a period of 10 years, 304 subjects at risk were included in ongoing surveillance with regular colonoscopies. To compile the medical findings and experience generated during this period, a retrospective cross sectional study was performed.

SUBJECTS

Subjects were classified into three family groups: families with hereditary non-polyposis colorectal cancer (HNPCC); families with hereditary colorectal cancer (HCC, non-Lynch syndrome); and a third group of families with only empirical risk estimates based on a family history of two close relatives (TCR) with colorectal cancer.

METHODS

The risk population was studied with regard to age at onset, prevalence, number, cancer risk, size, dysplasia, and distribution of adenomas. A comparison was made within the family groups and with a reference group representing the general population.

RESULTS

In total, 195 adenomas and six cancers were detected among 85 individuals. The relative risk of having an adenoma in the whole risk population compared with the general population was 2.6. Subjects from TCR families had most adenomas and HNPCC subjects had the least. A shift from proximal adenomas to distal carcinomas in families with HCC and TCR suggested a higher cancer risk in distal adenomas in these syndromes. HNPCC families showed a younger age at onset and adenomas with a higher degree of dysplasia. In HNPCC, there was a similar localisation of adenomas and carcinomas, suggesting a high risk of cancer in all adenomas.

CONCLUSIONS

There was clear overrepresentation of adenomas in all three family types compared with the reference population. In HNPCC, we found earlier onset of adenomas and faster progression to cancer. Families with HCC, and even more so TCR subjects, had a later onset and lower risk of cancer from proximal adenomas. Based on these results, surveillance protocols in Sweden have been revised.

Mapping of 13 horse genes by fluorescence in-situ hybridization (FISH) and somatic cell hybrid analysis

We report fluorescence in-situ hybridization (FISH) and somatic cell hybrid mapping data for 13 different horse genes (ANP, CD2, CLU, CRISP3, CYP17, FGG, IL1RN, IL10, MMP13, PRM1, PTGS2, TNFA and TP53). Primers for PCR amplification of intronic or untranslated regions were designed from horse-specific DNA or mRNA sequences in GenBank. Two different horse bacterial artificial chromosome (BAC) libraries were screened with PCR for clones containing these 13 Type I loci, nine of which were found in the libraries. BAC clones were used as probes in dual colour FISH to confirm their precise chromosomal origin. The remaining four genes were mapped in a somatic cell hybrid panel. All chromosomal assignments except one were in agreement with human-horse ZOO-FISH data and revealed new and more detailed information on the equine comparative map. CLU was mapped by synteny to ECA2 while human-horse ZOO-FISH data predicted that CLU would be located on ECA9. The assignment of IL1RN permitted analysis of gene order conservation between HSA2 and ECA15, which identified that an event of inversion had occurred during the evolution of these two homologous chromosomes.

Physical anchorage and orientation of equine linkage groups by FISH mapping BAC clones containing microsatellite markers

A horse bacterial artificial chromosome (BAC) library was screened for 19 microsatellite markers from unassigned or non-oriented linkage groups. Clones containing 11 (AHT20, EB2E8, HMS45, LEX005, LEX014, LEX023, LEX044, TKY111, UCDEQ425, UCDEQ464 and VIASH21) of these were found, which were from eight different linkage groups. The BAC clones were used as probes in dual colour FISH to identify their precise chromosomal origin. The microsatellite markers are located on nine different horse chromosomes, four of which (ECA6, ECA25, ECA27 and ECA28) had no previously in situ assigned markers.

Mohs' micrographic surgery for basal cell carcinomas on the eyelids and medial canthal area. II. Reconstruction and follow-up

PURPOSE

To report our experience of reconstruction and follow-up of eyelid basal cell carcinomas treated with Mohs' micrographic technique.

METHODS

Sixty-four periocular basal cell carcinomas, with a high risk of recurrence in one or more aspects with regard to location, size, morphology or prior treatment, were excised using Mohs' micrographic technique. All ensuing defects were repaired. The cases were followed prospectively for up to ten years. All complications and interventions were documented during the follow-up period.

RESULTS

The average size of the defect before repair was 21 mm (range 5-45 mm). The mean follow-up time was 49 months (range 3-120). The recurrence rate was 5% (3 of 64 cases). The three recurrences occurred after one, four and six years, respectively.

CONCLUSIONS

The recurrence rate of high risk tumours reported in this study was less than reported with other modes of treatment and comparable with that in other studies using Mohs' micrographic technique.

Mohs' micrographic surgery for basal cell carcinomas on the eyelids and medial canthal area. I. Characteristics of the tumours and details of the procedure

PURPOSE

To analyse the characteristics of eyelid basal cell carcinomas excised using Mohs' micrographic technique.

METHODS

Sixty-six eyelid basal cell carcinomas were excised using Mohs' micrographic technique. The tumours were classified into four subtypes; morpheiform, intermediate, nodular/micronodular and superficial. Data on previous treatment of the tumours were retrieved.

RESULTS

Thirty-two tumours (48%) were primary, 8 tumours (12%) were incompletely excised using conventional excision surgery and 26 tumours (39%) were recurrent. Nineteen of the 26 (73%) recurrent tumours and 14 of the 32 (44%) primary tumours were nodular/micronodular. To achieve radical excision, superficial tumours needed an average of 2.0, nodular/micronodular 2.5, intermediate 2.0 and morpheiform tumours 2.9 excisions.

CONCLUSIONS

Eyelid basal cell carcinomas with ill-defined borders or recurrent tumours are well suited for Mohs' micrographic surgery. The extensions of the tumours are difficult to determine even in some less aggressive subtypes such as superficial and nodular/micronodular basal cell carcinomas.

First comprehensive low-density horse linkage map based on two 3-generation, full-sibling, cross-bred horse reference families

Two 3-generation full-sibling reference families have been produced and form a unique resource for genetic linkage mapping studies in the horse. The F(2) generations, now comprising 61 individuals, consist of 28- to 32-day-old embryos removed nonsurgically from two pairs of identical twin mares. The same stallion sired all F(2)s such that the two full-sibling families are half-sibling with respect to each other. The families are crossbred to maximize levels of heterozygosity and include Arabian, Thoroughbred, Welsh Cob, and Icelandic Horse breeds. Milligram quantities of DNA have been isolated from each embryo and from blood samples of the parents and grandparents. The families have been genotyped with 353 equine microsatellites and 6 biallelic markers, and 42 linkage groups were formed. In addition, the physical location of 85 of the markers is known, and this has allowed 37 linkage groups to be anchored to the physical map. The inclusion of dams in the genotyping analysis has allowed the generation of a genetic map of the X chromosome. Markers have been assigned to all 31 autosomes and the X chromosome. The average interval between markers on the map is 10.5 cM, and the linkage groups collectively span 1780 cM. The results demonstrate the benefits for horse linkage mapping studies of genotyping on these unique full-sibling families, which comprise relatively few individuals, by the generation of a comprehensive low-density map of the horse genome.

Report of the International Equine Gene Mapping Workshop: male linkage map

The goal of the First International Equine Gene Mapping Workshop, held in 1995, was the construction of a low density, male linkage map for the horse. For this purpose, the International Horse Reference Family Panel (IHRFP) was established, consisting of 12 paternal half-sib families with 448 half-sib offspring provided by 10 laboratories. Blood samples were collected and DNA extracted in each laboratory and sent to the Lexington laboratory (KY, USA) for dispatch in aliquots to 14 typing laboratories. In total, 161 markers (144 microsatellites, seven blood groups and 10 proteins) were tested for all families for which the sire was heterozygous. Genealogies and typing data were sent for analysis to the INRA laboratory (Jouy-en-Josas, France) according to a specific format and entered into a database with input verification and output processes. Linkage analysis was performed with the CRIMAP program. Significant linkage was detected for 124 loci, of which 95 were unambiguously ordered using a multipoint analysis with an average spacing of 14.2 CM. These loci were distributed among 29 linkage groups. A more comprehensive analysis including synteny group data and FISH data suggested that 26 autosomes out of 31 are covered. The complete map spans 936 CM.

"I was always on guard"--an exploration of woman abuse in a group of women with musculoskeletal pain

OBJECTIVES

We aimed to explore experiences of abuse of women, and the way it was described and hinted at, in a group of women suffering from biomedically undefined long-term musculo-skeletal pain (UMSD).

METHOD

Twenty women patients participated. Data were gained through repeated semi-structured interviews conducted over 2 years and qualitatively analysed according to grounded theory.

RESULTS

Eleven participants had experienced abuse. Abuse was difficult to disclose due to shame, fear of the listener's preconceptions and fear of the abuser. In the interviews it was diminished, 'sugar-coated' and renamed. However, the women gave hints of abuse before avowing it. 'An understanding listener', who was expected to apprehend the hints, ask about abuse and confirm that it was valid to talk about it, was described as a precondition for disclosure.

CONCLUSION

This study suggests that it is important to explore woman abuse when investigating and treating UMSD. When there are hints of abuse, one should avoid blaming, stand by, be patient and ask about abuse even if the woman has once negated it. Fear of the abuser permeated the narratives and it is therefore suggested that doctors must consider carefully the danger involved.

The meanings of pain: an exploration of women's descriptions of symptoms

A grounded theory study with repeated semi-structured interviews was conducted to explore the meaning of the illness experiences of women patients, impaired by biomedically undefined musculoskeletal pain. Twenty female patients were recruited at an urban primary health care centre in northern Sweden, where two of the researchers work as family physicians. In this paper we focus on considerations of patient pain and analyze the findings from aspects linking together body, gender, and society. Four categories of symptom description were identified: bodily presentations, explanatory models, consequences of pain for the patient's activities, and consequences for her self-perception. The bodily symptoms signaled loss of control. The explanatory models consisted of physical damage and strain injuries, but were also psychological and self-blaming. The consequences of pain were described as negative consequences for the women's everyday life that challenged their self-perception as women. The participants' search and need for legitimization of their illness experiences, and the expectations placed on doctors as legitimizing agents was evident. To achieve the desired shared understanding in consultations, doctors must be aware of and consider not only physical signs and symptoms, but also the patients' gendered concerns and psycho-social circumstances.

Basal cell carcinoma of the eyelids and solar ultraviolet radiation exposure

AIMS

To compare the distribution of eyelid basal cell carcinoma (BCC) with the relative ultraviolet radiation (UVR) exposure to different sites on the eyelids.

METHODS

The location of BCC on the eyelids was allocated to one of seven regions. The UVR exposure was recorded with a polymer film attached to the eyelids at seven sites in a manikin and in human subjects.

RESULTS

Localisation of the 329 tumours was mainly on the lower eyelids (225 tumours), and the medial canthal regions (87 tumours). There was no association between UVR doses at the seven sites of the eyelids and the location of BCCs. The UVR exposure was similar on the upper and lower eyelids, while the number of tumours on the lower eyelids outnumbered the upper lids by a factor of 13 (17 upper, 225 lower)

CONCLUSION

UVR exposure only partially explains the aetiology of periorbital BCC.

A primary male autosomal linkage map of the horse genome

A primary male autosomal linkage map of the domestic horse (Equus caballus) has been developed by segregation analysis of 140 genetic markers within eight half-sib families. The family material comprised four Standardbred trotters and four Icelandic horses, with a total of 263 offspring. The marker set included 121 microsatellite markers, eight protein polymorphisms, five RFLPs, three blood group polymorphisms, two PCR-RFLPs, and one single strand conformation polymorphism (SSCP). One hundred markers were arranged into 25 linkage groups, 22 of which could be assigned physically to 18 different chromosomes (ECA1, ECA2, ECA3, ECA4, ECA5, ECA6, ECA7, ECA9, ECA10, ECA11, ECA13, ECA15, ECA16, ECA18, ECA19, ECA21, ECA22, and ECA30). The average distance between linked markers was 12.6 cM and the longest linkage group measured 103 cM. The total map distance contained within linkage groups was 679 cM. If the distances covered outside the ends of linkage groups and by unlinked markers were included, it was estimated that the marker set covered at least 1500 cM, that is, at least 50% of the genome. A comparison of the relationship between genetic and physical distances in anchored linkage groups gave ratios of 0.5-0.8 cM per Mb of DNA. This would suggest that the total male recombinational distance in the horse is 2000 cM; this value is lower than that suggested by chiasma counts. The present map should provide an important framework for future genome mapping in the horse.

"How could I even think of a job?"--Ambiguities in working life in a group of female patients with undefined musculoskeletal pain

OBJECTIVE

To explore the meaning of working life for a group of women sick-listed because of undefined, musculoskeletal pain disorders.

DESIGN

Repeated thematic interviews, analysed qualitatively according to grounded theory.

SETTING AND PARTICIPANTS

Twenty female patients, impaired by biomedically undefined pain and musculoskeletal disorders, were successively recruited at an urban primary health care centre in northern Sweden.

MAIN FINDINGS

There were discrepancies between work aspirations and work experiences concerning economic maintenance, social interaction, and personal recognition. The women had low-income jobs in fields threatened by redundancy, such as cleaning, care, and service. Family considerations had a strong impact on organization and priorities in paid work. In a situation of pain and sick leave, family orientation strengthened and work aspirations declined. Social and personal recognition was sought in the unpaid duties at home, and economic refuge in 'the state as supporter'.

IMPLICATIONS

To understand women with undefined musculoskeletal pain as patients, we must also understand their aspirations and experiences as workers, mothers, and spouses. 'Family considerations', 'diminishing paid work', and 'the state as supporter' are important concepts for understanding the women's sick role process.

Fitness loss and germline mutations in barn swallows breeding in Chernobyl

The severe nuclear accident at Chernobyl in 1986 resulted in the worst reported accidental exposure of radioactive material to free-living organisms. Short-term effects on human populations inhabiting polluted areas include increased incidence of thyroid cancer, infant leukaemia, and congenital malformations in newborns. Two recent studies have reported, although with some controversy, that germline mutation rates were increased in humans and voles living close to Chernobyl, but little is known about the viability of the organisms affected. Here we report an increased frequency of partial albinism, a morphological aberration associated with a loss of fitness, among barn swallows, Hirundo rustica, breeding close to Chernobyl. Heritability estimates indicate that mutations causing albinism were at least partly of germline origin. Furthermore, evidence for an increased germline mutation rate was obtained from segregation analysis at two hypervariable microsatellite loci, indicating that mutation events in barn swallows from Chernobyl were two- to tenfold higher than in birds from control areas in Ukraine and Italy.

Biophysical and physiological properties of a modified porcine surfactant enriched with surfactant protein A

Surfactant protein A (SP-A), a major protein component of natural pulmonary surfactant, is absent in exogenous surfactants currently used in clinical practice. We investigated the physical and physiological properties of one of these modified natural surfactants (Curosurf) after enrichment with 5% SP-A (SP-A-Curosurf). A pulsating bubble system was used for in vitro assessments and ventilated newborn rabbits for evaluation of in vivo effects. In the presence of various potential inhibitors (meconium 5 mg.mL-1, fibrinogen 5 mg.mL-1, albumin 25 mg.mL-1, or whole serum proteins 25 mg.mL-1), Curosurf at a concentration of 5 mg.mL-1 was inactivated while SP-A-Curosurf and natural porcine surfactant at the same concentration had normal maximum and minimum surface tension. This protective effect of SP-A was calcium dependent. In immature newborn rabbits, the improvement of lung-thorax compliance observed after treatment with 100 mg.kg-1 of SP-A-Curosurf was equivalent to that obtained with 200 mg.kg-1 of Curosurf. Similarly, in near-term newborn rabbits with respiratory failure induced by instillation of fibrinogen via the airways, the increase in compliance after administration of 100 mg.kg-1 of SP-A-Curosurf corresponded to that seen after treatment with 200 mg.kg-1 of Curosurf, whereas Curosurf at a dose of 100 mg.kg-1 had no substantial effect. Our data thus indicate that surfactant protein A increases the resistance of Curosurf to inactivation under in vivo conditions.

Long-term follow-up of cryosurgery of basal cell carcinoma of the eyelid

BACKGROUND

Basal cell carcinoma (BCC) is the most common malignant tumor of the eyelid and its incidence is increasing. It remains to be established which is the best treatment in terms of safety and cost-effectiveness.

OBJECTIVE

Our purpose was to analyze the long-term treatment results and possible side effects of cryosurgery of eyelid BCC.

METHODS

During the last 14 years 219 patients (222 tumors) treated for eyelid BCC with cryosurgery were followed up prospectively for up to 10 years.

RESULTS

The tumors cleared completely after treatment in all patients with no recurrence observed to date. Ninety-two patients were followed up for 5 years or more. Complications were few and minor. In 26 treated eyelids conjunctival overgrowth was noted.

CONCLUSIONS

We conclude that cryosurgery of BCC of the eyelid has a high cure rate, is cost-effective, and is well tolerated.

Altered expression of the retinoblastoma tumor-suppressor gene in leukemic cell lines inhibits induction of differentiation but not G1-accumulation

The retinoblastoma tumor-suppressor gene, RB, has been implicated in tumor suppression, in regulation of the cell cycle, and in mediating cell differentiation. RB is necessary for hematopoiesis in mice, and aberrant RB-expression is associated with the progress and prognosis of leukemia. We have used antisense oligonucleotides, established clones stably expressing an antisense RB construct, and also established clones over expressing the retinoblastoma protein (pRb) to study the role of RB expression in monocytic differentiation induced by all-trans retinoic acid (ATRA) or 1-alpha-25-dihyroxycholecalciferol (Vit D3) in the monoblastic cell line U-937 and erythroid differentiation induced by transforming growth factor beta1 (TGFbeta1) and hemin in the erythroleukemic cell line K562. A reduction in pRb production in antisense RB-transfected U-937 clones was shown. Antisense oligonucleotides as well as expression of the antisense RB construct suppressed differentiation responses to ATRA or Vit D3, as judged by the capability to reduce nitro blue tetrazolium, by the appearance of monocyte-related cell surface antigens and by morphologic criteria. K562 cells showed decreased differentiation response to TGFbeta1, but not to hemin, when incubated with antisense oligonucleotides. U-937 antisense RB-transfected cells were also suppressed in their ability to upregulate levels of hypophosphorylated pRb when induced to differentiate. Although U-937 cells incubated with antisense oligonucleotides and clones expressing the antisense RB construct were hampered in their ability to differentiate on incubation with ATRA or Vit D3, the induced G0/G1-accumulation was similar to differentiating control cells treated with ATRA or Vit D3. Intriguingly, U-937 clones overexpressing RB were also inhibited in their differentiation response to ATRA or Vit D3 but not inhibited in their ability to respond with G0/G1 accumulation when induced with these substances. The results indicate that pRb plays a role in induced differentiation of U-937 cells as well as K562 cells involving mechanisms that, at least partially, are distinct from those inducing G1 accumulation.

Perimetric probability maps to separate change caused by glaucoma from that caused by cataract

We describe a new method for analysis of change in glaucomatous visual fields with the object to differentiate between changes caused by glaucoma from those caused by cataract. New pattern deviation change probability maps were developed from a prospectively collected glaucoma material and designed to be sensitive to changes in localized field loss, but to be unaffected by media-induced perimetric change. We compared the new change probability maps with the commercially available total deviation change probability maps in series of Humphrey perimetric tests in a glaucoma material of 43 eyes of 35 patients, who had undergone cataract surgery. When using the total deviation maps, considerable differences were seen between fields obtained before and after cataract surgery. Much smaller differences were seen when using the new change probability maps, that almost eliminated the common and disturbing effect of increasing cataract. This new tool could be of considerable help in differentiation between progressive glaucomatous visual field loss and deterioration caused by increasing media opacities.