Clinical outcomes of triclosan-coated barbed suture in open hernia repair: a retrospective cohort study

PURPOSE

We assessed clinical outcomes of patients undergoing open hernia repair using STRATAFIX™ Symmetric, a barbed triclosan-coated suture (TCS; Ethicon), versus conventional polydioxanone suture (PDS) for abdominal wall closure.

METHODS

This single-center retrospective cohort study identified patients undergoing hernia repair. The site used PDS from 2013 to 2016 and switched exclusively to barbed TCS in 2017. Outcomes were assessed at 30, 60, and 90 days. Multivariate regression analyses and Cox proportional hazards models were used.

RESULTS

Of 821 hernia repairs, 446 used barbed TCS and 375 used conventional PDS. Surgical site infections (SSIs) were significantly less frequent with barbed TCS (60 days, 5.9% vs. 11.4%; P = 0.0083; 90 days, 5.9% vs. 11.7%; P = 0.006) and this remained consistent after multivariate adjustment (60 days, OR [95% CI]: 0.5 [0.3-0.9]; 90 days, 0.5 [0.3-0.9]). Among patients with SSI, deep SSIs were less frequent with barbed TCS (60 days, 9.1% vs. 35.7%; P = 0.022; 90 days, 9.1% vs. 34.9%; P = 0.0252). Barbed TCS significantly reduced the risk of perioperative complications (HR [95% CI]: 0.5[0.3-0.8]; P = 0.0058). Hospital length of stay was 2.5 days shorter with barbed TCS (mean [95% CI]: 5.7[4.9-6.6] vs. 8.2[7.3-9.1] days; P < 0.0001). No differences in reoperation rate over time were observed by type of suture (HR[95% CI]:1.3 [0.5-3.4]; P = 0.4793).

CONCLUSIONS

This study showed that patients who underwent open hernia repair appeared to recover equally well regardless of the suture type. In addition, the use of barbed TCS was associated with significantly reduced risk of perioperative complications and hospital length of stay.

Decreased mebrofenin uptake in patients with non-colorectal liver tumors requiring liver volume augmentation-a single-center analysis

BACKGROUND

Posthepatectomy liver failure (PHLF) remains a life-threatening complication after hepatectomy. To reduce PHLF, a preoperative assessment of liver function is indispensable. For this purpose, 99mTc-mebrofenin hepatobiliary scintigraphy with SPECT (MSPECT) can be used. The aim of the current study was to evaluate the predictive value of MSPECT for PHLF in patients with non-colorectal liver tumors (NCRLT) compared to patients with colorectal liver metastasis (CRLM) undergoing extended liver resection.

METHODS

We included all patients undergoing extended liver resections via two-stage procedures between January 2019 and December 2021 at the University Medical Center Hamburg-Eppendorf, Germany. All patients received a preoperative MSPECT.

RESULTS

Twenty patients were included. In every fourth patient, PHLF was observed. Four patients had PHLF grade C. There were no differences between patients with CRLM and NCRLT regarding PHLF rate and future liver remnant (FLR) volume. Patients with CRLM had higher mebrofenin uptake in the FLR compared to those with NCRLT (2.49%/min/m2 vs. 1.51%/min/m2; p = 0.004).

CONCLUSION

Mebrofenin uptake in patients with NCRLT was lower compared to those patients with CRLM. However, there was no difference in the PHLF rate and FLR volume. Cut-off values for the mebrofenin uptake might need adjustments for different surgical indications, surgical procedures, and underlying diseases.

Prognostic factors of poor postoperative outcomes in gastrectomies

Background

Gastric cancer is one of the most common cancers worldwide and is the third most common cause of cancer related death. Improving postoperative results by understanding risk factors which impact outcomes is important. The current study aimed to compare immediate perioperative outcomes following gastrectomy.

Methods

302 patients following gastric resections over a 10-year period (January 2009-January 2020) were identified in a database and retrospectively analysed. Epidemiological as well as perioperative data was analysed, and a univariate and multivariate analysis performed to identify risk factors for in-hospital mortality.

Results

In general, gastrectomies were mainly performed electively (total vs. subtotal 95% vs. 85%, p = 0.004). Patients having subtotal gastrectomy needed significantly more PRBC transfusions compared to total gastrectomy (p = 0.039). Most emergency surgeries were performed for benign diseases, such as ulcer perforations or bleeding and gastric ischaemia. Only emergency surgery was significantly associated with poorer overall survival (HR 2.68, 95% CI 1.32-5.05, p = 0.003).

Conclusion

In-hospital mortality was comparable between total and subtotal gastrectomies. Only emergency interventions increased postoperative fatality risk.

P-142 CLINICAL AND ECONOMIC OUTCOMES OF ABSORBABLE KNOTLESS BARBED SUTURE VERSUS OTHER CONVENTIONAL SUTURES FOR ABDOMINAL MIDLINE CLOSURE IN PATIENTS UNDERGOING OPEN HERNIA REPAIRS

Aim

We assessed clinical and economic outcomes of patients undergoing open hernia repair using absorbable knotless barbed suture versus conventional absorbable suture for abdominal wall closure.

Methods

This retrospective cohort study identified patients undergoing hernia repair at a single center between 2013 and 2020. Fixed follow-up of 30, 60, and 90 days were used to assess outcomes (peri-operative complications, and resource utilization). Multivariate analyses for outcomes and Cox Proportional Hazards models for time to readmission and complications were conducted.

Results

Of 821 hernia repairs, 446 used absorbable knotless barbed suture and 375 used conventional absorbable suture. Baseline characteristics were largely similar between the groups. Surgical site infections (SSI) were significantly less frequent with absorbable knotless barbed suture (60-day, 5.9% vs. 11.4%; P=0.0083; 90-day, 5.9% vs. 11.7%; P=0.006) and remained consistent after multivariate adjustment (60-day, OR [95% CI]: 0.52 [0.29–0.92]; 90-day, 0.51 [0.28–0.90]). Among patients with SSI, deep SSI were less frequent with absorbable knotless barbed suture (60-day, 9.1% vs. 35.7%; P=0.022; 90-day, 9.1% vs. 34.9%; P=0.0252). Absorbable knotless barbed suture significantly reduced the risk of peri-operative complications over time (HR 0.57 [95% CI 0.36–0.92]; P=0.0203). Hospital length of stay was, on average, 2.74 days longer in conventional absorbable suture patients (mean [95% CI] 8.75 [7.83–9.78] vs. 6.01 [5.16–6.99] days; P&lt;.0001).

Conclusions

Significant differences between sutures were seen with peri-operative infections, which occurred less frequently with absorbable knotless barbed suture and less severe. Peri-operative complications and length of stay were significantly reduced with absorbable knotless barbed suture.

AB1050 CHARACTERISTICS OF PATIENTS WITH COINCIDENT GOUT AND ADVANCED CHRONIC KIDNEY DISEASE

Background

Patients with chronic kidney disease (CKD) are at increased risk for developing gout1 and vice versa.2 Those with both gout and CKD present distinct challenges for patients and physicians because of the high prevalence of other comorbidities and restrictions on gout medication use, including non-steroidal anti-inflammatories3,4 and some oral urate-lowering therapies (ULTs).5 This unique patient population has not been well characterized using real-world data.

Objectives

This retrospective chart review study of patients with coincident gout and CKD was conducted to better understand patient characteristics and treatment patterns of this population. This study is unique in that patient data were obtained from nephrologists, allowing a glimpse of how they view gout and its management.

Methods

111 nephrologists provided de-identified medical record data of their most-recently seen advanced (stage 3─5) CKD patients. Patients met study criteria for gout if any of the following were true: gout listed as a comorbidity, ULT use, or visible tophi or gout flares documented. A patient’s gout was determined to be uncontrolled if they had serum uric acid >6 mg/dL in addition to ≥1 visible tophus, ≥2 gout flares in the past year, or gouty arthritis (≥1 tender or swollen joint). Characteristics of this unique population were examined, along with gout management patterns. Differences between patients with controlled and uncontrolled gout were also investigated using data from patients’ most recent evaluation.

Results

173 patients with stages 3-5 CKD and who met study criteria for gout were included. Mean age was 58.3±18.1 years and BMI averaged 32.0 ± 11.8 kg/m2. A higher than expected proportion of patients were female (47%). The most common comorbidities were hypertension (85%), diabetes mellitus (47%), anemia of CKD (42%), CKD-mineral bone disorder (41%), ischemic heart disease (23%), and congestive heart failure (21%). Mean CKD duration was 4.1 ± 5.5 years, mean estimated glomerular filtration rate (eGFR) at most recent visit was 32.3 ± 13.9 ml/min/1.73 m2, and 62% were using a ULT. 23 patients (13%) had uncontrolled gout (48% female, 63.1 ± 16.4 years, mean eGFR 32.0 ± 14.6 ml/min/1.73 m2), all of whom had been prescribed a ULT. Compared with controlled gout patients, uncontrolled patients had higher rates of pulmonary hypertension (14% vs. 4%), gout-related chronic pain in the 12-months prior to data collection (63% vs. 42%), and joint involvement (joint swelling, tenderness, flexibility loss, and/or damage/lesions on x-ray; 26% vs. 9%). Colchicine was also used more frequently in uncontrolled gout patients (26% vs. 7%).

Conclusion

The coincident gout with advanced CKD population described here shows unique differences from the general gout population, including a high proportion of females (47%). Given that women have a lower likelihood of developing gout at the same serum uric acid level,6 this finding was particularly surprising (general gout population: 67% male7). Importantly, nearly 40% of included patients were not utilizing a ULT, leaving them susceptible to developing the painful and debilitating sequalae of uncontrolled gout. Additionally, 41% of the study population had a CKD-related mineral bone disorder, indicating that patients with coincident gout and CKD may have bones that are more vulnerable to gout-related bone damage. Our study confirms a high prevalence of gout and its associated comorbidities in patients with advanced CKD and suggests another nephrology education opportunity to highlight the potential benefits of gout monitoring, earlier intervention, and management.

References

[1]Safiri S, et al. Arthritis Rheumatol 2020;72:1916-27.

[2]Feig DI. Curr Opin Nephrol Hypertens 2009; 18: 526–530.

[3]Stamp LK, et al. Nat Rev Rheumatol. 2021; 17(10): 633–641.

[4]Wallace SL, et al. J Rheumatol 1991; 18(2): 264-9.

[5]Abdelatif AA and Elkhalili N. Am J Ther 2014; 21: 523-34.

[6]Bhole V, et al. Arthritis Rheum 2010;62:1069-76.

[7]Francis-Sedlak M, et al. Rheumatol Ther 2021;8:183-97.

Disclosure of Interests

Leonard Stern Speakers bureau: Horizon Therapeutics, Consultant of: Horizon Therapeutics, Richard Johnson Shareholder of: Colorado Research Partners LLC and XORTX Therapeutics, Speakers bureau: Horizon Therapeutics, Consultant of: Horizon Therapeutics, Payam Shakouri Speakers bureau: Horizon Therapeutics and Relypsa, Consultant of: Horizon Therapeutics, Amod Athavale Grant/research support from: Horizon Therapeutics, Brian LaMoreaux Shareholder of: Horizon Therapeutics, Employee of: Horizon Therapeutics, Brad Marder Shareholder of: Horizon Therapeutics, Employee of: Horizon Therapeutics, Sreedhar Mandayam Shareholder of: Medingenii Capital LLC and Prosalus Capital LLC, Speakers bureau: Otsuka and Alexion, Consultant of: US Renal Care and Aurinia, Grant/research support from: Travere, Norvartis, Omeros, Roche, Vertex, Equillium, Goldfinch Bio, and Pfizer

[Cost per responder associated with romiplostim and rituximab treatment for adult primary immune thrombocytopenia in France]

PURPOSE OF THE STUDY

This analysis compared the response rates and cost per responder associated with romiplostim and rituximab in adult immune thrombocytopenia from the French National Health System payer perspective.

METHODS

A decision analytic model was developed to estimate the cost per patient and per responder of treating adult immune thrombocytopenia patients with romiplostim versus rituximab over 6 months. A systematic literature review identified phase 3 randomized controlled trials. Published response rates were extracted (response definition: ≥50×10(9) platelets/liter). Resource utilization was based on French and international treatment guidelines, and clinical expert opinion. Unit costs were derived from literature and French reimbursement lists, and included the costs of routine physician visits, treatment administration, and emergency care. Non-responders incurred bleeding-related event costs.

RESULTS

The literature review identified a phase 3 randomized controlled trial for romiplostim with a response rate of 83%. Due to a lack of phase 3 randomized controlled trials for rituximab, a systematic review of studies was selected as the best source, reporting a response rate of 62.5%. Romiplostim and rituximab were associated with similar treatment costs, with an estimated cost per patient for romiplostim of €17,456 and €17,068 for rituximab. Rituximab resulted in a 30% higher cost per responder (€27,308 for rituximab versus €21,031 for romiplostim). Romiplostim use reduced drug administration, intravenous immunoglobulin, and bleeding-related hospitalization costs compared to rituximab.

CONCLUSIONS

Due to its high efficacy leading to lower bleeding-related costs, romiplostim represents an efficient use of resources for adult immune thrombocytopenia patients in the French healthcare system.

Hormone therapy in women after heart transplantation

BACKGROUND

Hormone therapy (HT) for menopausal women has been controversial regarding cardiac outcomes and adverse effects. Studies suggest that HT may cause increase in heart disease, stroke, and cancer. The use of HT in heart transplantation has not been firmly established.

METHODS

The records of 356 female heart transplant recipients, undergoing transplantation from 1994 to 2011, were reviewed. We found 19 patients after age 35 years who were initiated on HT for noncontraceptive purposes. These patients were compared 1:3 with a contemporaneous control group matched for age, sex, era, and time after heart transplantation (paired for time from transplantation to initiation of HT). We assessed for subsequent 5-year survival, freedom from cardiac allograft vasculopathy (CAV; stenosis ≥ 30%), freedom from nonfatal major adverse cardiac events (NF-MACE; myocardial infarction, heart failure, percutaneous cardiac intervention, stroke, and need for pacemaker/defibrillator), and subsequent 1-year freedom from any-treated rejection. Additionally, we compared significant adverse effects of HT between groups.

RESULTS

HT patients compared with control subjects revealed no significant difference in subsequent 5-year survival (79% vs 75%; P = .66), freedom from CAV (90% vs 88%; P = .85), or NF-MACE (90% vs 93%; P = .65). There was also no significant difference in subsequent 1-year freedom from any-treated rejection between the groups. Other adverse effects of HT including subsequent 5-year incidence of thrombosis (pulmonary embolus), malignancy, and stroke were also similar to control subjects.

CONCLUSIONS

HT is not associated with poor outcome or adverse effects in female heart transplant patients after age 35 years. However, a larger cohort of patients is necessary to confirm these observations.

Evaluation of cinacalcet HCl treatment after kidney transplantation

BACKGROUND

Hyperparathyroidism often remains or develops after kidney transplantation. Vitamin D sterol used as treatment for an elevated parathyroid hormone (PTH) level and associated bone disease may be contraindicated due to hypercalcemia. The calcimimetic cinacalcet HCl (cinacalcet), which lowers PTH and calcium (Ca) in chronic kidney disease patients, may represent an alternate therapeutic modality.

METHODS

This multicenter, retrospective, observational study examined 41 kidney transplant patients receiving cinacalcet for ≥3 months starting ≥3 months posttransplantation. Levels of intact PTH, Ca, and phosphorus (P) were examined during the assessment phase (3-6 months after initiation).

RESULTS

Median PTH decreased 21.8% during the assessment phase (P < .001), with 32.5% of patients exhibiting a ≥30% decrease in PTH from baseline. Median Ca decreased 6.8% (P < .0001). Median serum P rose 10.0% (P = .0124), but remained within normal limits. The estimated glomerular filtration rate was stable throughout the study.

CONCLUSIONS

Cinacalcet may be useful for the treatment of hyperparathyroidism after kidney transplantation. Randomized, prospectively designed clinical trials are required to confirm these results.

Patient and physician perceptions of treatment of moderate-to-severe chronic pain with oral opioids

OBJECTIVE

To study physician and patient perceptions of moderate-to-severe chronic pain and its management with oral opioids.

METHODS

Two separate surveys were developed and administered to one of two respective study groups: patients and physicians. All study participants recruited from a pool of individuals who had previously agreed to participate in market research. Survey questions addressed the impact of various factors (e.g., quality of life indicators, potential for opioid addiction, side-effects) on pain management decision making, patient satisfaction and compliance. Responses for the first 500 patients and 275 physicians to respond were assessed using descriptive statistics.

RESULTS

On average, patients were 53 years of age, white (89%), and female (71%). The majority of patients (80%) had been taking oral opioids longer than 6 months. Physicians reported that 45% of their patients received schedule II opioids, with 27% having severe chronic pain. Patients indicated the most common activities interfered with by chronic pain were exercising (76% of patients), working outside the home (67%), and job responsibilities (60%). When developing a treatment approach physicians considered patients' sleeping (91%), walking (86%), maintaining an independent lifestyle (84%), and job responsibilities (83%). Patients and physicians both rated the ability to relieve pain and the duration of relief as the most important factors when considering opioid therapy. The majority (63%) of patients reported experiencing opioid side effects. When physicians discontinued opioids due to side effects, the most frequent reason was nausea (78%) for immediate-release opioids, and constipation (64%) for extended-release formulations.

CONCLUSION

The ability to relieve pain and the duration of that pain relief are the most important factors for both patients and physicians when selecting an opioid. A high percentage of patients surveyed experienced side effects related to their treatment, which may impact adherence and overall treatment effectiveness. Study results should be assessed within study limitations including responder and selection biases, physicians responded about their patients, who were not the same patients surveyed, and the fact that the survey instruments were not formally validated. Further research is warranted to address these limitations.

Therapeutic care in metastatic renal cell carcinoma during the follow-up phase of the RECORD-1 phase III trial

e17531

Background: Following drug discontinuation for progression or adverse event in a clinical trial for relapsed or stage IV kidney cancer, supportive care including surgery, palliative radiotherapy, or bisphosphonates continue to be recommended by National Comprehensive Cancer Network (NCCN). However, published data on active therapeutic agents given to patients following study drug discontinuation in recent clinical trials is limited. Methods: World Health Organization Anatomical Therapeutic Chemical codes or therapeutic names, captured from the follow-up phase in a phase III clinical trial (RECORD-1) of patients with metastatic renal cell carcinoma (mRCC) patients, were used to describe antineoplastic therapies following discontinuation of study drug. Prior to trial, patients had progressed on at least one VEGFr-TKI therapy. Results: Of the 130 patients with follow-up after discontinuation of study drug, 78.5% received at least one of the following: corticosteroids, radiotherapy, protein kinase inhibitors, mTOR inhibitor, pyrimidine analogues, monoclonal antibodies, interferons, and investigational drugs. Among patients who received an active agent, nearly three-quarters (73.5%) utilized targeted therapy (protein kinase inhibitors, mTOR inhibitor, monoclonal antibodies). Conclusions: In a clinical trial setting with mRCC patients who have received several classes of systemic therapy, care delivered following study drug discontinuation often includes an active antineoplastic agent, despite the limited supportive evidence in this setting. While the placebo control with supportive care in a double-blind phase is acceptable to evaluate the efficacy and safety of a therapy for regulatory approval purposes, decision makers must also consider how these data may inform comparisons with the usual alternatives available to and used by physicians and patients in the non-trial setting.

[Table: see text]

Serum resistin is not associated with obesity or insulin resistance in humans

BACKGROUND

Resistin has proposed link with obesity related insulin resistance and type 2 diabetes. The physiologic role of resistin in humans remains unknown. It is suggested that circulating resistin levels are not associated with obesity or insulin resistance in humans. However, the effects of weight loss on serum resistin concentration has not been studied. In order to better understand the physiologic role of resistin in human obesity, we measured the serum resistin concentration in subjects with severe obesity (before and after 6-months of dietary intervention) to test the hypothesis that serum resistin concentrations are elevated amongst individuals with severe obesity and weight loss would reduce these levels.

METHODS

Seventy-one obese subjects (defined as BMI > 35 kg/m2) who were randomized to low fat (LF) vs low carbohydrates (LC) diets and who completed the 6-month follow-up were studied. Their baseline demographic information was collected and serum resistin, insulin, glucose were measured at baseline and at 6-months.

RESULTS

Subjects in LC diet lost more weight than LF (-19.54 +/- 7.87 lbs vs -7.83 +/- 11.23 lbs., p = 0.001). Insulin sensitivity (HOMA) improved in LC group compared with LF group [-3.72 +/- 9.84 (LC) vs +1.31 +/- 7.31 (LF), p = 0.006]. Serum resistin levels did not decrease in either diet.

CONCLUSIONS

Our study found that despite a significant weight loss and improvement in insulin sensitivity there was no reduction in serum resistin concentration in morbidly obese men with metabolic syndrome suggesting that resistin does not play a central role in obesity related insulin resistance.

Syndrome de Di George, étude rétrospective de 52 cas

The deletion of chromosome 22q11.2 is involved in the majority of DiGeorge or velo-cardiofacial syndrome. The phenotypic variability was noted in the "CATCH 22" acronym. This acronym doesn't recapitulate the full spectrum of the symptoms. The diagnosis of this syndrome can be done with the prenatal diagnosis, with fetal pathology or with a child alive.

METHODS

Review of 52 cases with the microdeletion 22q11. Six cases were diagnosed during the prenatal period, 12 cases at fetal pathology examination, and 34 cases during infancy.

RESULTS

Cardiac malformations were the major indications (75%) to search for the microdeletion. The facial dysmorphy was difficult to diagnose during the antenatal period or in dead foetus, thereby it was not often recognized. The renal anomalies usually present in 35% of cases, were diagnosed in only 6 to 16% of the cases in our study.

CONCLUSION

Phenotypic diversity of the DiGeorge syndrome is important. Its knowledge allows to better determine the indications of the research of the microdeletion. 22q11.2.

A rapid method for illustrating features in both coding and non-coding regions of a genome

A bitmap display of the Fourier spectra has been developed which allows convenient whole chromosome scanning for genes and other features. Use of a limited sliding window gives rapid visualization and localization of coding regions in the chromosomes, as well as non-coding features such as repetitive DNA. The method works particularly well on organisms with a skewed base composition, to provide an overview of genomic features.

Discovering patterns in Plasmodium falciparum genomic DNA

A method has been developed for discovering patterns in DNA sequences. Loosely based on the well-known Lempel Ziv model for text compression, the model detects repeated sequences in DNA. The repeats can be forward or inverted, and they need not be exact. The method is particularly useful for detecting distantly related sequences, and for finding patterns in sequences of biased nucleotide composition, where spurious patterns are often observed because the bias leads to coincidental nucleotide matches. We show here the utility of the method by applying it to genomic sequences of Plasmodium falciparum. A single scan of chromosomes 2 and 3 of P. falciparum, using our method and no other a priori information about the sequences, reveals regions of low complexity in both telomeric and central regions, long repeats in the subtelomeric regions, and shorter repeat areas in dense coding regions. Application of the method to a recently sequenced contig of chromosome 10 that has a particularly biased base composition detects a long internal repeat more readily than does the conventional dot matrix plot. Space requirements are linear, so the method can be used on large sequences. The observed repeat patterns may be related to large-scale chromosomal organization and control of gene expression. The method has general application in detecting patterns of potential interest in newly sequenced genomic material.

Motion direction signals in the primary visual cortex of cat and monkey

When an image feature moves with sufficient speed it should become smeared across space, due to temporal integration in the visual system, effectively creating a spatial motion pattern that is oriented in the direction of the motion. Recent psychophysical evidence shows that such "motion streak signals" exist in the human visual system. In this study, we report neurophysiological evidence that these motion streak signals also exist in the primary visual cortex of cat and monkey. Single neuron responses were recorded for two kinds of moving stimuli: single spots presented at different velocities and drifting plaid patterns presented at different spatial and temporal frequencies. Measurements were made for motion perpendicular to the spatial orientation of the receptive field ("perpendicular motion") and for motion parallel to the spatial orientation of the receptive field ("parallel motion"). For moving spot stimuli, as the speed increases, the ratio of the responses to parallel versus perpendicular motion increases, and above some critical speed, the response to parallel motion exceeds the response to perpendicular motion. For moving plaid patterns, the average temporal tuning function is approximately the same for both parallel motion and perpendicular motion; in contrast, the spatial tuning function is quite different for parallel motion and perpendicular motion (band pass for the former and low pass for the latter). In general, the responses to spots and plaids are consistent with the conventional model of cortical neurons with one rather surprising exception: Many cortical neurons appear to be direction selective for parallel motion. We propose a simple explanation for "parallel motion direction selectivity" and discuss its implications for the motion streak hypothesis. Taken as a whole, we find that the measured response properties of cortical neurons to moving spot and plaid patterns agree with the recent psychophysics and support the hypothesis that motion streak signals are present in V1.

Sequence complexity for biological sequence analysis

A new statistical model for DNA considers a sequence to be a mixture of regions with little structure and regions that are approximate repeats of other subsequences, i.e. instances of repeats do not need to match each other exactly. Both forward- and reverse-complementary repeats are allowed. The model has a small number of parameters which are fitted to the data. In general there are many explanations for a given sequence and how to compute the total probability of the data given the model is shown. Computer algorithms are described for these tasks. The model can be used to compute the information content of a sequence, either in total or base by base. This amounts to looking at sequences from a data-compression point of view and it is argued that this is a good way to tackle intelligent sequence analysis in general.