Using Unlabeled Information of Embryo Siblings from the Same Cohort Cycle to Enhance In Vitro Fertilization Implantation Prediction

High-content time-lapse embryo imaging assessed by machine learning is revolutionizing the field of in vitro fertilization (IVF). However, the vast majority of IVF embryos are not transferred to the uterus, and these masses of embryos with unknown implantation outcomes are ignored in current efforts that aim to predict implantation. Here, whether, and to what extent the information encoded within "sibling" embryos from the same IVF cohort contributes to the performance of machine learning-based implantation prediction is explored. First, it is shown that the implantation outcome is correlated with attributes derived from the cohort siblings. Second, it is demonstrated that this unlabeled data boosts implantation prediction performance. Third, the cohort properties driving embryo prediction, especially those that rescued erroneous predictions, are characterized. The results suggest that predictive models for embryo implantation can benefit from the overlooked, widely available unlabeled data of sibling embryos by reducing the inherent noise of the individual transferred embryo.

Healthcare utilization, costs, and epidemiology of Huntington's disease in Israel

Introduction

Data on Huntington's disease (HD) epidemiology, treatment patterns, and economic burden in Israel are scarce.

Methods

Annual prevalence and incidence of HD (ICD-9-CM 333.4) were assessed in the Israel-based Maccabi Healthcare Services (MHS) database 2016-2018. Adherence (medication possession rate [MPR], proportion of disease covered) were assessed for adult people with HD (PwHD) 2013-2018. Healthcare resources utilization (HCRU) and costs related to inpatient and outpatient visits and all medications in 2018 were assessed for PwHD, who were randomly matched to MHS members without HD (1:3) by birth-year and sex.

Results

Overall, 164 patients had at least one HD diagnosis. Annual prevalence and incidence were 4.45 and 0.24/100,000, respectively. A total of 67.0% of adult patients (n = 106) were taking tetrabenazine (median MPR and proportion of disease covered, 74.3% and 30.2%, respectively), 65.1% benzodiazepines (75.8% and 32.3%), and 11.3% amantadine (79.2% and 6.0%). Over a 1-year follow-up, PwHD (n = 81) had significantly more neurologist, psychiatrist, physiotherapist, and speech therapist visits (P < 0.05 for each) and more hospitalization days (P < 0.0001) compared with matched controls (n = 243). Total healthcare and medication costs per patient (US dollars) were significantly higher for PwHD than controls ($7,343 vs. $3,625; P < 0.001).

Discussion/Conclusion

PwHD have greater annual HCRU and medical costs than MHS members without HD in Israel. Among those who have taken medications, adherence was lower than 80% (both MPR and proportion of disease covered), which may translate into suboptimal symptom relief and quality of life.

The variability of diagnosed migraine epidemiology amongst different municipalities in southern Israel

BACKGROUND

Appropriate and timely diagnosis is one of the most important milestones in effective migraine care and is affected by public awareness, access to medical care, health care systems, and physicians' knowledge. We assessed the variability in migraine diagnosis rates in different communities under universal national health coverage in Israel.

METHODS

In this population-based retrospective, observational, cohort study, adult (≥18 years) migraine patients were identified in the computerized database of the southern district of the Clalit Health Services Health Maintenance Organization (HMO) based on recorded diagnosis and/or purchase of specific anti-migraine acute medication (triptans). Migraine prevalence in 2018 was calculated in the entire study population and in different municipalities. We utilized a standardized (age and gender) mortality ratio (SMR) approach for comparison among the municipalities.

RESULTS

In 2018, a total of 29,938 migraine patients were identified out of 391,528 adult HMO members, with an overall prevalence (per 10,000) of migraine of 764.64 (7.65%), 1143.34 (11.43%) for women, and 374.97 (3.75%) for men. Among the municipalities, adjusted prevalence (per 10,000) ranged from 386.15 (3.86%) to 1320.60 (13.21%). The female-to-male ratio ranged from 1.8:1 to 5.1:1. Prevalence rates were positively associated with the socioeconomic status of the municipalities (Spearman rho = 0.472, P = 0.031).

CONCLUSIONS

High variability in the prevalence of diagnosed migraine suggests underdiagnosis. Resources for awareness and educational programs should be directed to low diagnosed prevalence communities.

Migraine epidemiology and comorbidities in Southern Israel: a clinical database study in a universal health coverage setting

BACKGROUND

Understanding migraine epidemiology and its burden is crucial for planning health policies and interventions at the local level as well as at the global level. National policies in Israel rely on global estimations and not on local data since local epidemiologic studies had not previously been performed. In this study, we evaluated the epidemiology of migraine in the southern district of Israel using the electronic medical records database of the largest Israeli health maintenance organization (HMO).

METHODS

In this population-based, retrospective, observational cohort study, adult migraine patients were identified in the computerized database of the southern district of the Clalit Health Services HMO (total population, 0.75 million). Patients were identified based on recorded diagnosis (International Classification of Diseases, Ninth Revision) and/or claims for specific anti-migraine medication (triptans) between 2000 and 2018. A 1:2 age-, gender-, and primary care clinic-matched control group was used for evaluation of comorbidities.

RESULTS

In 2018, a total of 29,938 patients with migraine were identified out of 391,528 adult HMO members. Most of the patients were women (75.8%), and the mean ± standard deviation age at diagnosis was 36.94 ± 13.61 years. The overall prevalence of migraine (per 10,000) was 764.64 (7.65%), 1143.34 (11.43%) for women and 374.97 (3.75%) for men. The highest prevalence was observed in patients aged 50 to 60 years and 40 to 50 years (1143.98 [11.44%] and 1019.36 [10.19%], respectively), and the lowest prevalence was among patients aged 18 to 30 years and > 70 years (433.45 [4.33%] and 398.49 [3.98%], respectively).

CONCLUSIONS

This is the first large-scale epidemiologic study of migraine prevalence in Israel. Compared to international estimations, migraine appears to be underdiagnosed in the southern district of Israel.

O-073 Artificial intelligence (AI) based triage for preimplantation genetic testing (PGT); an AI model that detects novel features in the embryo associated with ploidy

Study question

Can an AI based triage system noninvasively detect aneuploidy in preimplantation embryos in a precise and valid manner?

Summary answer

Using a feature extraction approach to identify features in time-lapse images, an AI model was validated and found to noninvasively detect ploidy with unprecedented accuracy.

What is known already

Invasive PGT with trophectoderm biopsy is the gold standard for evaluating the genetic integrity of an embryo prior to transfer. Even so, its utility and diagnostic accuracy is debated due to concern of structural damage, sampling bias and viability after vitrification-warming. Though several noninvasive methods for evaluating ploidy have been developed, their main limitations lay in their accuracy. This study reports on the ongoing validation of an AI model that relies on feature extraction and thresholding techniques to distinguish between aneuploid and euploid embryos; the model is intended to be used in clinical settings for PGT triage and preferential transfer.

Study design, size, duration

In this single-center study, we used a retrospective dataset consisting of time-lapse images from 2,502 preimplantation embryos with known ploidy status to train and validate the AI model.

Participants/materials, setting, methods

The model utilized videos captured from time-lapse incubator (Embryoscope) up to 144 hours post-fertilization with chromosome analysis performed using next-generation sequence technology as ground truth labels. The data set was divided using an 70/15/15 training-validation-test split of the data. The AI model included convolutional neural network extracted features alongside spatial features based on several biological and clinical characteristics known to associate with ploidy, embryo behavior, and function. Performances were measured by validation and test-set accuracy.

Main results and the role of chance

Five feature modules were included in the AI model for ploidy evaluation. All modules were analyzed separately and combined: (I) automated detection of abnormal morphokinetic patterns (t2-t8, tM, tSB, tB, tHB) differentiated between the two classes (aneuploid and euploid) to predict aneuploidy with an accuracy of 52%, p &lt; 0.05; (II) previously validated embryo grading classification algorithm demonstrated an association between A and C-grade embryos with euploidy and aneuploidy, respectfully, with an accuracy of 68%, p &lt; 0.05; (III) differential cell division activity and compaction between the two classes predicted aneuploidy with an accuracy of 73%, p &lt; 0.05; (IV): AI-based classification of mitochondrial DNA content, measured as 0.5 micron irregularities in time-lapse images, predicted aneuploidy with an accuracy of 77%, p &lt; 0.05; blastocoelic contractions of more than 8 microns in diameter predicted aneuploidy with 56% accuracy, p &lt; 0.05. Using our AI model, we were able to integrate all 5 features, thereby achieving an unprecedented 90% accuracy. Two features – detection of abnormal morphokinetic patterns and blastocoelic contractions – occur in a minority of embryos (in 3% and 20% of all embryos in the database, respectively). When they do occur, they independently predict aneuploidy with an accuracy of 90% and 82%, demonstrating the robustness of our multi-feature model.

Limitations, reasons for caution

Our AI model needs to be tested on a large, multi-centric dataset to ensure standardization and ability to be replicated in different settings. Even so, given our high degree of demonstrated accuracy, we conclude that our single-center dataset was sufficient for developing the initial validation of the model reported here.

Wider implications of the findings

The ‘explainability’ and implementation of our AI model enables more objective embryo quality assessment and improves the clinics’ ability to prioritize embryos for PGT and preferential transfer using a validated and trusted framework that reduce dramatically the chances of transferring an aneuploid embryo to our patients.

Trial registration number

not applicable

O-004 The bias is out of the bag: IVF culture dish well number influences embryo selection decision-making and implantation outcome

Study question

Is there a selection bias against embryos placed in higher-numbered wells inside a multi-well IVF culture dish. Does this selection bias alone impact implantation outcomes?

Summary answer

Top-quality embryos present in higher-numbered wells are statistically less likely to be selected for transfer, independent of any differences in quality or development between wells.

What is known already

Substantial intra-and inter-observer variability in embryo selection, as well as differences in quality assessment and laboratory environment, have been shown to affect IVF success. Currently many clinics have adopted stringent guidelines to control for human errors and workflow variation. Still, the impact of errors in laboratory and medical procedures was reported as high as 12%. This is particularly relevant for the IVF lab, where high workload and stress influence rate of errors and patient outcome. This groundbreaking study emphasizes how cognitive tendencies are inherent to the embryo selection process.

Study design, size, duration

This study used a retrospective dataset from three highly experienced fertility clinics (1 US and 2 European clinics). A total of 4,275 Fresh IVF cycles were analyzed. For each treatment cycle, embryo quality grades, corresponding embryo well numbers, day 5 selection and implantation outcomes were documented. All cycles were performed using the EmbryoSlide 12-well culture dish and a time-lapse system. All three datasets were analyzed separately and also combined.

Participants/materials, setting, methods

For each dataset, three analyses were conducted: (1) total number of selected embryos were calculated for each corresponding well number; (II) the proportion of implanted embryos, relative to the total number of selected embryos, were quantified to calculate the “success rate” for each well number; (II) the distribution of top-quality embryos between wells were quantified and compared. Results were normalized by total number of transferred embryos and IVF implantation success rates reported for each clinic.

Main results and the role of chance

A negative trend was found between well number, ranging from 1-12, and number of embryos selected for transfer. This trend was significant (p &lt; 0.05) and occurred independently in each dataset. Odds ratios (OR) for the relation between selecting embryos for transfer from wells 1-5, and from 8-12 = Clinic A: 2.16, Clinic B: 1.78, Clinic C: 2.45. Alternative hypotheses were tested: (1) top-quality embryos are clustered in lower-numbered wells during culture; (2) enhanced embryo quality and conditions are found in lower-numbered wells, which should manifest in higher rates of implantation. Results for each clinic showed a statistically even distribution of top-quality embryos between wells (within 2 standard deviations from the mean; not significant), yet ‘success rate’ for transferred embryos increased by well number (by 12-30% between wells 1-5 and wells 8-12; OR = 1.19, 1.06, 1.08 for Clinic A, B, and C, respectively). An inverse trend existed between an embryo’s likelihood of being selected for transfer, and its likelihood of implanting. We conclude that embryologists may tend to select the first acceptable embryo for transfer. Embryos from higher-numbered wells were significantly more likely to implant, since they overcame this bias when equitably evaluated and selected for transfer.

Limitations, reasons for caution

Though our findings were significant, they need to be repeated on larger datasets with more inter-centre variation, and key embryo culture and outcome variables recorded.

Wider implications of the findings

This study emphasizes the inherent human error that exists inside IVF clinics. Machine learning systems that reduce human bias and increase objective standardization, even if they are not inherently better than embryologists, would improve implantation rates. Future studies should be directed toward AI based technologies that can accomplish this.

Trial registration number

Not Applicable

P-277 An artificial intelligence (AI) deselection model for top-quality blastocysts: algorithmic analysis of morphokinetic features for aneuploidy may increase implantation rates

Study question

Can an AI deselection model identify distinct morphokinetic patterns in top-quality blastocyst with unknown ploidy that fail to implant?

Summary answer

An AI based deselection model was able to predict implantation failure based on morphokinetic features previously found to associate with aneuploidy.

What is known already

Aneuploidy is the most common explanation for implantation failure of high-quality blastocysts. Yet, high-quality blastocysts with unknown ploidy that fail to implant are often morphologically indistinguishable from blastocysts that succeed to implant. Our previously published results (ESHRE 2021) demonstrated that aneuploid blastocysts were more likely to reach development events (t2-t8) later, and that the timing between each event was statistically longer (p &lt; 0.001), when compared to euploid embryos. Given that delayed morphokinetic rates are tightly linked to ploidy, we investigated whether similar known morphokinetic features were associated with implantation failure in top-graded embryos.

Study design, size, duration

Time-lapse sequences of 3,259 top-quality blastocysts from fresh single embryo transfer cycles with known implantation outcomes were analyzed using an AI-based algorithm. The algorithm utilized convolutional neural network extracted temporal features based on multiple morphokinetic parameters known to associate with ploidy.

Participants/materials, setting, methods

time-lapse sequences and morphokinetic events were algorithmically analyzed to measure the rate of mitotic division events and compare the number of embryos in each category (implanted/nonimplanted) that reached each developmental event at least one standard deviation (SD) later than the mean for implanted embryos.

Main results and the role of chance

Results showed statistical differences in the following morphokinetic features between the two categories: t2, t3, t4, and t3-t4 (p &lt; 0.05). Implanted top-graded blastocysts were likely to reach t2, t3, and t4 after 25.23 ± 3.8 SD, 36.06 ± 3.4 SD, and 37.14 hours ±3.6 SD, respectively. The time gap between t3 and t4 was found to be 12.25 hours ± 5.31 SD. Given this, we followed the methodology described above to propose cutoff values (in hours) that differentiated between non-implanted and implanted top-graded blastocysts based on their morphokinetic profiles. Implantation failure was found to be associated with the likelihood of reaching t2 after 28.61 hours (OR = 2.36, CI 0.96-5.77), t3 after 39.46 (OR = 3.48, CI 1.62-7.47), and t4 after 40.79 hours (OR = 2.23, CI 1.09- 4.53). A time gap between t3 and t4 of more than 17.56 hours was also associated with implantation failure (OR = 2.48, CI 1.12-5.48), indicating perturbed mitotic activity. The cutoff values proposed here were incorporated into the algorithm for optimized deselection of morphologically similar top-quality blastocysts with delayed morphokinetic profiles.

Limitations, reasons for caution

This study needs to be validated on a larger, multi-centric dataset that takes into account more morphokinetic features associated with ploidy in order to increase the robustness of our algorithm.

Wider implications of the findings

For the first time, our algorithmic model proposed here demonstrates the utility of an AI tool to deselect top-graded blastocysts that would otherwise be selected for transfer based on conventional morphologic assessment alone.

Trial registration number

Not Applicable

O-084 Computer vision can distinguish between euploid and aneuploid embryos. A novel artificial intelligence (AI) approach to measure cell division activity associated with chromosomal status

Study question

Can we distinguish between top-grade euploid and aneuploid embryos by AI measurement of cell edges in time-lapse videos?

Summary answer

Aneuploid embryos can be distinguished from euploid embryos by AI determination of a longer time to blastulation and higher cell activity.

What is known already

Continuous monitoring of the embryo development has brought out morphokinetic parameters that are used to predict pre-implantation genetic testing (PGT) results. Previous publications showed that euploid embryos reach blastulation earlier than non-euploid embryos. However, time-lapse data are currently under-utilized in making predictions about embryo chromosomal content. AI and computer vision could take advantage of the massive amount of data embedded in the images of embryo development. This is the first attempt to distinguish between euploid and aneuploid embryos by computer vision in an objective and indirect way based on the measurement of cell edges as a proxy for cell activity.

Study design, size, duration

We performed a retrospective analysis of 1,314 time-lapse videos from embryos cultured to the blastocyst stage with PGT results. This single-center study involved two phases; a comparison of the start time of blastulation between euploid (n = 544) and aneuploid embryos (n = 797). In phase two, we designed a novel methodology to examine whether precise measurement of cell edges over time could reflect cell activity differences in blastulation.

Participants/materials, setting, methods

We assumed that the delay in blastulation is reflected by higher cell activity that could be determined accurately for the first time using computer vision and machine learning to measure the length of the edges (from t2 to t8). We compared computer vision based measurements of cell edges, reflecting cell number and size, in videos of 231 top-grade euploid (n = 111) and aneuploid (n = 120) embryos.

Main results and the role of chance

The mean and standard deviation of blastulation start time was 100.1±6.8 h for euploid embryos and 101.8±8.2 h for aneuploid embryos (p &lt; 0.001). Regarding the measurement of cell activity, a computer vision algorithm identified the edges and provided a certainty score for each edge, higher when the algorithm is more certain that this is a cell edge (as opposed to noise in the images). A threshold was set to distinguish cell edges from noise using this score. The following results for top-grade embryos are shown as the sum of the edge lengths (µm) average of 160 pictures per embryo (frames between t2 and t8). The total length of the cell edges increased from two cells (420±85 µm) to eight cells (861±237 µm), in line with the mitosis events. Both the average total edge measured (450±162 µm for euploid embryos and 489±215 µm for aneuploid embryos, p &lt; 0.01) and the average total of the difference between consecutive frames (135±47 µm for euploid embryos and 153±64 µm for aneuploid embryos, p &lt; 0.01) were higher for aneuploid embryos than for euploid embryos. A regression model to differentiate between the two classes achieved 73% sensitivity and 73% specificity on this dataset.

Limitations, reasons for caution

The main limitation of this study is the difficulty to correlate our findings to other measure of cell activity. A more robust AI function (using not only cell edges lengths) would be required for future analysis to measure the cell activity in cell division up to the blastocyst stage.

Wider implications of the findings

Our results show for the first time that an AI based system can precisely measure microscopic cell edges in the dividing embryo. Using this novel method, we could distinguish between euploid and aneuploid embryos. This non-invasive method could further enhance our knowledge of the developing embryo.

Trial registration number

Not Applicable

O-085 In-depth analysis of embryo development: Differences among monosomic, trisomic and chromosomally chaotic embryos compared to euploid embryos

Study question

Is there any visible variation in the development of aneuploid embryos depending on the type of chromosome abnormality?

Summary answer

There were significant visible differences in the development of euploid, monosomic, trisomic and, especially, chaotic embryos.

What is known already

Aneuploidy rates are remarkably high in in vitro fertilized human embryos, with up to 50% of embryos diagnosed as aneuploid based on preimplantation genetic testing for aneuploidies (PGT-A). However, very little is known about the impact of specific aneuploidies during the early human embryo development. A recent publication showed that embryos with single chromosomal gain or loss reached the blastocyst stage later or earlier depending on the chromosome affected (Shahbazi et al., 2020). In our study, we wanted to detect observable differences in embryo behavior between embryos with different chromosomal abnormalities during the entire in vitro development.

Study design, size, duration

This was a retrospective study including 2,500 blastocysts with PGT-A results. Embryos were cultured in EmbryoScope systems until the fifth/sixth day of development (up to the time of trophectoderm biopsy). Automatic-annotations for division times and quality gradings were supervised routinely by senior embryologists using Guided Annotations Tool. Out of the total, 1,000 were euploid embryos used for reference and 1,500 were aneuploid embryos with one or more defects, including monosomic, trisomic and chromosomally chaotic embryos.

Participants/materials, setting, methods

Chromosome analysis was performed using next-generation sequence technology. Then, an in-depth analysis of time-lapse videos and supervised-automatic annotations was performed. We calculated the proportion of embryos, in each aneuploid category, that reached one specific event later than the expected value for euploid embryos plus one standard deviation. Later, we calculated the “relative risk” of an embryo of reaching the milestone late. We did the same for the time between milestones and for pairs of milestones.

Main results and the role of chance

Every aneuploid category was more likely to reach each specific embryo developmental event later than euploid embryos and the time gaps between developmental milestones were also statistically longer in aneuploid embryos (p &lt; 0.0001). The following results were the most interesting relative risks (RR) when we compared the proportion of embryos (in each aneuploid category) to the proportion of euploid embryos (RR for euploid = 1). For reaching the division time to two cells (t2): 1.31 in monosomic embryos, 1.50 in trisomic embryos and 2.43 in chaotic embryos. For the division time to four cells (t4): 1.42 in monosomic embryos, 1.54 in trisomic embryos and 3.07 in chaotic embryos. For the division time to eight cells (t8) and the time of starting blastulation: 1.45 in monosomic embryos, 1.22 in trisomic embryos and 2.74 in chaotic embryos. Combined milestones were stronger indicators than each milestone by itself, the RR were: 1.63 in monosomic embryos, 1.81 in trisomic embryos and 3.35 in chaotic embryos for t2 and t4; 1.50 in monosomic embryos, 1.80 in trisomic embryos and 2.84 in chaotic embryos for t2 and t8; 1.46 in monosomic embryos, 1.90 in trisomic embryos and 3.43 in chaotic embryos for t4 and t8.

Limitations, reasons for caution

At this stage, we did not go down to specific chromosome abnormality as there were very few cases in each fully detailed category. Also, not all the embryos reached every developmental milestone.

Wider implications of the findings

Aneuploid embryos were significantly different from euploid embryos in the first five days of development. A large proportion of aneuploid embryos could be rejected because their developmental milestones falling outside the normal range. This could form part of an automated system for determining euploidy/aneuploidy from observation of embryos in vitro.

Trial registration number

1902-VLC-018-MM

Rate of Strabismus Detection on Digital Photographs Increases by Using Off-center Near Target

PURPOSE

To increase the detection rate of strabismus on digital photographs, with the ultimate aim of developing a new automated strabismus detection algorithm.

METHODS

In this prospective case series, the authors acquired digital face photographs of 409 children with manifest or latent strabismus, using a 14-million-pixel camera with CCD image sensor. Of the last 52 enrolled, 34 image sets were selected for this study: 29 with manifest and 5 with latent strabismus. Images were taken at a distance of 40 to 70 cm in primary position, with the camera lens as the fixation target and in slight off-center fixation, and using a novel target of small light-emitting diodes mounted onto the camera case. The location of the corneal light reflection was manually calculated in relation to the center of the pupil in both eyes and ocular deviation as the difference in corneal light reflection location between the two eyes. In orthotropia, the expected deviation is zero.

RESULTS

In children with phorias, the mean corneal light reflection location difference between the eyes was -0.10 ± 0.14 mm in primary position and -2.02 ± 0.39 mm in off-center fixation. Using a threshold of ±0.5 mm on either side of zero for central and of 2 mm for off-center fixation, sensitivity to detect strabismus increased from 65.6% in central to 79.3% in off-center fixation, respectively. The calculation of specificity will require inclusion of a population of individuals without strabismus.

CONCLUSIONS

Off-center fixation onto a near target ensures that participants are actively looking at the target and may increase accommodative effort, thereby increasing the detection rate of strabismus. [J Pediatr Ophthalmol Strabismus. 2017;54(2):90-96.].

Omentopexy improves vascularization and decreases stricture formation of esophageal anastomoses in a dog model

BACKGROUND

Anastomotic strictures are common after primary esophageal anastomosis in pediatric patients. Recent studies provided evidence that omentopexy may improve vascularization of gastroesophageal anastomoses and decrease the rate of stricture-related complications. The effect of omentopexy on primary esophago-esophageal anastomosis, however, is unknown. The aim of the current study was to examine the role of omentopexy on the healing process of primary midesopageal anastomoses.

METHODS

Six dogs were operated on. A 5-cm portion of the midesophagus was resected, and continuity was restored by end-to-end anastomosis. In 3 dogs, an omental pedicle was placed around the anastomotic region. Eating patterns were recorded and functional swallowing was evaluated by fluoroscopic studies. Eight weeks after the operations, the experimental animals were killed and anastomotic lumen diameters and vascularization of the anastomotic sites were evaluated by radiographic studies and histologic examination, respectively.

RESULTS

Two dogs in the omentopexy group were able to resume regular feeding, whereas none of the dogs in the control group were able to tolerate solid food intake. Fluoroscopic studies found preserved motility patterns of the esophagus in the omentoesophagopexy group, while prestenotic dilatation and delayed food clearance through the anastomosis were observed in the control group. Histologically, neovascularization was observed at the anastomotic site in the omentoesophagopexy group in contrast to the marked degree of fibrosis displayed in the control group.

CONCLUSIONS

Omentopexy may improve vascularization and decrease stricture formation after primary esophagoesophageal anastomosis.

PF-IND: probability algorithm and software for separation of plant and fungal sequences

The separation of plant and fungal sequences in EST pools by bioinformatic methods is difficult because of sequence similarities between plants and fungi, lack of enough sequence information, and the short length of the isolated fragments. An algorithm and software that utilize the differences in codon usage bias to discriminate between plant and fungal sequences are described. The software (PF-IND) includes five pairs of fungi and their host plants that can be used to analyze a large number of related species. Analysis of a sequence provides an arbitrary value that defines the likelihood that a sequence will be a fungal or a plant gene. The software can distinguish between homologous fungal and plant genes and it helps identify the correct reading frame of unknown expressed sequence tags (ESTs) for which BLAST analyses do not provide clear information. Short sequences of 100-150 bp can be analyzed with high confidence. PF-IND analysis of 100 sequences derived from fungal infected plants identified the origin of 94 sequences. Only 66 sequences were identified by a BLASTX analysis of the same 100 ESTs. Overall, PF-IND is a novel bioinformatic tool aimed at assisting the research of fungus-plant interactions.

Does prehospital fluid administration impact core body temperature and coagulation functions in combat casualties?

BACKGROUND

Administration of large amounts of fluids to trauma patients, in the absence of surgical control, may increase bleeding, cause hypothermia and coagulopathy which may worsen the bleeding and increase morbidity and mortality. The purpose of our study is to examine the impact of prehospital fluid administration to military combat casualties on core body temperature and coagulation functions.

METHODS

Prospective data were collected on all cases of moderately (9 < or = ISS < or = 14) and severely (ISS > or = 16) injured victims wounded in South Lebanon, treated by Israeli military physicians and evacuated to hospitals in Israel, over a two-year period. Data regarding prehospital phase of injury (timetables, amount of fluids) and upon hospital arrival (initial core body temperature, prothrombin time [PT], partial thromboplastin time [PTT]) were examined for monotonic relation using Spearman's non-parametric test.

RESULTS

Fifty-three moderately injured and 31 severely injured patients were included in the study. The average evacuation time for the moderately injured group was 109.3 +/- 44.8 min, and for the severely injured 100.3 +/- 38.4 min (P value=NS). The mean volume of fluids administered was 2.39 +/- 1.52 and 2.49 +/- 1.47 l, respectively (P=NS). No statistical correlation was found between core body temperature, PT or PTT, measured upon hospital arrival, and prehospital fluid treatment. In addition, no correlation was found between core body temperature on hospital arrival and prehospital time, or between prehospital fluid volumes and prehospital time. The mean core body temperature of the moderately injured patients was 36.8 degrees C, and that of severely injured was 35.8 degrees C (P=0.026).

CONCLUSIONS

With proper control of blood loss and avoidance of excessive fluid administration, moderately and severely injured combat casualties in 'low intensity conflict' in South Lebanon can be resuscitated with fluid volumes that do not result in a coagulation deficit or hypothermia. The core body temperature on arrival at the hospital is related to the severity of the injury.

Prehospital stabilization of the cervical spine for penetrating injuries of the neck - is it necessary?

The purpose of this study was to assess the specific indications, benefits and risks associated with cervical spine stabilization during pre-hospital care of penetrating neck injuries. We retrospectively reviewed hospital charts and autopsy reports of 44 military casualties in Israel with a penetrating neck injury during a period of 4.5 years. A review of the literature was also carried out. In eight of 36 hospitalized casualties (22%) a life-threatening sign was diagnosed in the exposed neck - large or expanding haematoma, or subcutaneous emphysema. Surgical stabilization of the cervical spine was not performed for any of the casualties. It was concluded that life threatening complications due to penetrating neck injury are common and may be overlooked if the neck is covered by a stabilization device. It is extremely rare for a penetrating injury to result in an unstable cervical spine. New management guidelines concerning pre-hospital stabilization are suggested.

Preliminary experience with postmortem computed tomography in military penetrating trauma

BACKGROUND

Postmortem examination serves as a tool for confirmation of clinical diagnosis, "quality" assurance, and education. In Israel, mostly because of religious reasons, most families withhold their permission to perform autopsies. To obtain objective information regarding the death of soldiers, the Israel Defense Forces Medical Corps started in September of 1997 to perform postmortem computed tomographic (PMCT) scans. The purpose of our study is to determine what information can be obtained from the PMCT scans.

METHODS

In a period of 16 months, 27 soldiers were killed in low-intensity conflicts and PMCT was obtained in 22 cases. Medical data obtained from the field medical care providers were collected and compared with PMCT results.

RESULTS

Several examples of patients whose death was determined at the scene either before any medical intervention or after initiation of resuscitative treatment are shown in our study and compared with the clinical impression of the treating physician. Two examples of autopsy results are compared with PMCT results. Gas was detected in various parts of the circulatory system in many cases. The significance of this finding, described in our study for the first time, needs further investigation.

CONCLUSION

PMCT scanning has limits in detecting superficial injuries and injuries of the extremities and determining the exact route of fragments through body tissues in penetrating military trauma. It also cannot serve as a tool for examining ammunition or the protection provided by various armors. However, it can provide a substantial amount of evidence that, when reviewed with the clinical information obtained from the physician at the scene, can help in assessing the treatment given at the field and point toward the probable cause of death.

Prehospital blood transfusion in prolonged evacuation

BACKGROUND

Prehospital blood transfusion for hemorrhaging trauma patients has been used infrequently and is controversial. Currently, there is no satisfactory nonsanguineous fluid therapy for use during prolonged transport, such as in military or rural trauma.

METHODS

We retrospectively reviewed prehospital data and hospital charts of all trauma patients in Israel who had received prehospital blood transfusion during a period of 30 months.

RESULTS

Forty patients received 60 U of Rh-positive type O packed red blood cells. Mean time from injury to hospital admission was 120 minutes. Twenty-one of 31 patients admitted to the hospital alive (68%) received additional blood transfusions during the initial resuscitation phase, justifying the prehospital transfusion. Of nine documented admissions with hemoglobin of less than 7 g/dL, one patient died of exsanguination. There was one case of a minor adverse reaction that could be attributed to prehospital transfusion.

CONCLUSION

Prehospital blood transfusion is justified in certain trauma patients, especially when long prehospital transport is required. Blood may be safely maintained and used by physicians with little experience in care of major trauma.

Characterization of DNA topoisomerase activity in two strains of Mycoplasma fermentans and in Mycoplasma pirum

DNA topoisomerases (topos) are essential enzymes that participate in many cellular processes involving DNA. The presence of the DNA-gyrase genes in various mycoplasmas has been reported elsewhere. However, the characterization of DNA topo activity in mycoplasmas has not been previously undertaken. In this study, we characterized the topo activity in extracts of Mycoplasma fermentans K7 and incognitus and in Mycoplasma pirum, as well as in partially purified extract of M. fermentans K7. The topo activity in these microorganisms had the following properties. (i) The relaxation of supercoiled DNA was ATP dependent. (ii) ATP independent relaxation activity was not detected. (iii) Supercoiling of relaxed topoisomers was not observed. (iv) The relaxation activity was inhibited by DNA gyrase and topo IV antagonists (novobiocin and oxolinic acid) and by eukaryotic topo II (m-AMSA [4'-(9-acridylamino)methanesulfon-m-anisidide]) and topo I antagonists (camptothecin). Other eukaryotic topo II antagonists (teniposide and etoposide) did not affect the topo relaxation activity. (v) Two polypeptides of 66 and 180 kDa were found to be associated with the mycoplasma topo activity. These results suggest that the properties of the topo enzyme in these mycoplasma species resemble those of the bacterial topo IV and the eukaryotic and the bacteriophage T4 topo II. The findings that mycoplasma topo is inhibited by both eukaryotic topo II and topo I antagonists and that m-AMSA and camptothecin inhibited the growth of M. fermentans K7 in culture support our conclusion that these mycoplasma species have topo with unique properties.