Permanent or absorbable suture material for sacrospinous ligament fixation: Does it matter?

OBJECTIVE

To evaluate success and safety of sacrospinous ligament fixation (SSLF) using permanent versus absorbable suture materials 12 months following surgery.

STUDY DESIGN

Following IRB approval, the electronic medical records of women who underwent SSLF in the gynecology department of a university-affiliated medical center from November 2012 to September 2021 were retrospectively reviewed. SSLF was carried out using Capio®and Digitex™, with either absorbable (polyglactin-910 or polydioxanone) sutures (group 1), or permanent (polypropylene) sutures (group 2), Pre-operative and post-operative assessment included prolapse staging using the pelvic organ prolapse quantification system and validated quality of life questionnaires (Pelvic Floor Distress Inventory and Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire-12). Patients with postoperative information on objective and subjective outcome at 12 months were included in final analysis. Anatomical success was defined as POP stage < 2 at 12-months following surgery. For statistical analysis, the Mann-Whitney test was used for continuous variables, Fisher's exact test for dichotomous variables, and Chi-squared test of independence for variables with>2 categories.

RESULTS

During the study period, 234 women underwent SSLF. One-hundred and forty-two patients (60.7 %) returned at the 12-month follow-up and were included in final analysis. Seventy-two (50.7 %) patients had absorbable suture and 70 patients (49.3 %) had permanent suture. Estimated blood loss was significantly higher in group 1 [100 (50-150) cc vs 50 (50-100) cc respectively, p =.016]. Moderate to severe pain on POD-1 was significantly higher in group 2 [VAS: 2.00 (0.00-4.00) vs 4.00 (3.00-5.75) respectively, p =.001]. Anatomical success, defined as POP ≤ stage 2 at 12 months, was similar between groups: 69 % in group 1 vs 67 % in group 2 (p =.77). Subjective cure was similar between groups, 97.2 % in group 1 vs 94.3 % in group 2 (p =.44). At the 12-month follow-up, none of the patients had gluteal pain. The rate of de-novo dyspareunia was similar between groups: 4 women (5.9 %) in the absorbable suture group versus 2 women (3.3 %) in the permanent suture group (p =.49).

CONCLUSIONS

Our findings suggest that absorbable or permanent suture material does not affect outcome of SSLF. Permanent sutures may be related to increased immediate postoperative pain.

Post-hemithyroidectomy Pregnancy Thyroid Function Surveillance - Frequency, Adherence and Guideline Impact

OBJECTIVE

Post-hemithyroidectomy women are at increased risk for gestational subclinical hypothyroidism. Therefore, the American Thyroid Association (ATA) recommends increased thyroid function surveillance for this subgroup of pregnant women. The Purpose of this study was to evaluate the frequency of thyroid function surveillance during pregnancy in post-hemithyroidectomy women, and to evaluate the adherence to the 2017 ATA guidelines and its possible impact since being published, on thyroid function surveillance rates.

METHODS

A retrospective study including all pregnancies conceived by post-hemithyroidectomy women operated at our institution between the years 1997-2020. The study cohort was subdivided by pregnancy date prior to 2018 and 2018 and onwards to evaluate the impact of the 2017 ATA guidelines. Adherence to the guidelines was defined as at least one TSH test in each trimester.

RESULTS

After exclusions, a total of 120 pregnancies conceived by 66 women who underwent hemithyroidectomy surgeries were included in this study. Overall, serum TSH examinations were performed during the first, second and third pregnancy trimesters in 86.6%, 40% and 16.6% of pregnancies (P<0.005), respectively. The examination rate since 2018 was 88%, 40% and 8% for first, second and third trimester, respectively (P<0.005).

CONCLUSION

Adherence to the latest ATA guidelines is low and its publication in 2017 did not increase the thyroid function surveillance rate in post-hemithyroidectomy women. Better patient education regarding the risks of gestational hypothyroidism following hemithyroidectomy and improved communications between treating surgeons, obstetricians, and endocrinologists may improve these rates.

Patterns of care and dropout rates from outpatient mental healthcare in low-, middle- and high-income countries from the World Health Organization's World Mental Health Survey Initiative

BACKGROUND

There is a substantial proportion of patients who drop out of treatment before they receive minimally adequate care. They tend to have worse health outcomes than those who complete treatment. Our main goal is to describe the frequency and determinants of dropout from treatment for mental disorders in low-, middle-, and high-income countries.

METHODS

Respondents from 13 low- or middle-income countries (N = 60 224) and 15 in high-income countries (N = 77 303) were screened for mental and substance use disorders. Cross-tabulations were used to examine the distribution of treatment and dropout rates for those who screened positive. The timing of dropout was examined using Kaplan-Meier curves. Predictors of dropout were examined with survival analysis using a logistic link function.

RESULTS

Dropout rates are high, both in high-income (30%) and low/middle-income (45%) countries. Dropout mostly occurs during the first two visits. It is higher in general medical rather than in specialist settings (nearly 60% v. 20% in lower income settings). It is also higher for mild and moderate than for severe presentations. The lack of financial protection for mental health services is associated with overall increased dropout from care.

CONCLUSIONS

Extending financial protection and coverage for mental disorders may reduce dropout. Efficiency can be improved by managing the milder clinical presentations at the entry point to the mental health system, providing adequate training, support and specialist supervision for non-specialists, and streamlining referral to psychiatrists for more severe cases.

Multiple Traumas, Maternal Depression, Mother-Child Relationship, Social Support, and Young Children's Behavioral Problems

This study examined whether maternal depression, mother-child relationships, and maternal perceived social support mediate the associations between child's exposure to multiple traumatic events and behavioral problems. We recruited a representative sample of 904 Israeli (Jewish and Arab) mothers and their 2- to 6-year-old children. Data collection was conducted through structured face-to-face interviews with the mothers between July and November 2011. All measures were completed by the mothers. We used the child's and mother's exposure to political violence questionnaires, Child Behavior Checklist (CBCL), a short version of the Parental Acceptance-Rejection Questionnaire (PARQ), the Center for Epidemiologic Studies Depression Scale (CES-D), and the Medical Outcomes Study (MOS) Social Support Survey. The research study model was tested using path analysis. The model showed a very good fit to the data, suggesting that maternal rejection, maternal depression, and social support play an important role in child's behavioral problems in the context of multiple traumatic events. Higher levels of maternal rejection were significantly associated with greater children behavior problems. Maternal rejection mediated the associations between maternal depressive symptoms and child's behavioral problems. Maternal perceived social support mediated the associations between child's exposure to multiple traumatic events and child's behavioral problems; child's exposure to multiple traumatic events was associated with lower levels of maternal perceived social support. In turn, lower levels of perceived social support were associated with higher levels of behavioral problems. In conclusion, in accordance with the "social stress framework," social support has a mediation role in the association between exposure to traumatic events and child's behavioral problems. Thus, enhancing social support to mothers to young children in the context of multiple traumatic events is essential for children resiliency.

Perceived helpfulness of treatment for posttraumatic stress disorder: Findings from the World Mental Health Surveys

BACKGROUND

Perceived helpfulness of treatment is an important healthcare quality indicator in the era of patient-centered care. We examine probability and predictors of two key components of this indicator for posttraumatic stress disorder (PTSD).

METHODS

Data come from World Mental Health surveys in 16 countries. Respondents who ever sought PTSD treatment (n = 779) were asked if treatment was ever helpful and, if so, the number of professionals they had to see to obtain helpful treatment. Patients whose treatment was never helpful were asked how many professionals they saw. Parallel survival models were estimated for obtaining helpful treatment in a specific encounter and persisting in help-seeking after earlier unhelpful encounters.

RESULTS

Fifty seven percent of patients eventually received helpful treatment, but survival analysis suggests that it would have been 85.7% if all patients had persisted in help-seeking with up to six professionals after earlier unhelpful treatment. Survival analysis suggests that only 23.6% of patients would persist to that extent. Odds of ever receiving helpful treatment were positively associated with receiving treatment from a mental health professional, short delays in initiating help-seeking after onset, absence of prior comorbid anxiety disorders and childhood adversities, and initiating treatment before 2000. Some of these variables predicted helpfulness of specific treatment encounters and others predicted persistence after earlier unhelpful encounters.

CONCLUSIONS

The great majority of patients with PTSD would receive treatment they considered helpful if they persisted in help-seeking after initial unhelpful encounters, but most patients whose initial treatment is unhelpful give up before receiving helpful treatment.

Findings From World Mental Health Surveys of the Perceived Helpfulness of Treatment for Patients With Major Depressive Disorder

IMPORTANCE

The perceived helpfulness of treatment is an important patient-centered measure that is a joint function of whether treatment professionals are perceived as helpful and whether patients persist in help-seeking after previous unhelpful treatments.

OBJECTIVE

To examine the prevalence and factors associated with the 2 main components of perceived helpfulness of treatment in a representative sample of individuals with a lifetime history of DSM-IV major depressive disorder (MDD).

DESIGN, SETTING, AND PARTICIPANTS

This study examined the results of a coordinated series of community epidemiologic surveys of noninstitutionalized adults using the World Health Organization World Mental Health surveys. Seventeen surveys were conducted in 16 countries (8 surveys in high-income countries and 9 in low- and middle-income countries). The dates of data collection ranged from 2002 to 2003 (Lebanon) to 2016 to 2017 (Bulgaria). Participants included those with a lifetime history of treated MDD. Data analyses were conducted from April 2019 to January 2020. Data on socioeconomic characteristics, lifetime comorbid conditions (eg, anxiety and substance use disorders), treatment type, treatment timing, and country income level were collected.

MAIN OUTCOMES AND MEASURES

Conditional probabilities of helpful treatment after seeing between 1 and 5 professionals; persistence in help-seeking after between 1 and 4 unhelpful treatments; and ever obtaining helpful treatment regardless of number of professionals seen.

RESULTS

Survey response rates ranged from 50.4% (Poland) to 97.2% (Medellín, Columbia), with a pooled response rate of 68.3% (n = 117 616) across surveys. Mean (SE) age at first depression treatment was 34.8 (0.3) years, and 69.4% were female. Of 2726 people with a lifetime history of treatment of MDD, the cumulative probability (SE) of all respondents pooled across countries of helpful treatment after seeing up to 10 professionals was 93.9% (1.2%), but only 21.5% (3.2%) of patients persisted that long (ie, beyond 9 unhelpful treatments), resulting in 68.2% (1.1%) of patients ever receiving treatment that they perceived as helpful. The probability of perceiving treatment as helpful increased in association with 4 factors: older age at initiating treatment (adjusted odds ratio [AOR], 1.02; 95% CI, 1.01-1.03), higher educational level (low: AOR, 0.48; 95% CI, 0.33-0.70; low-average: AOR, 0.62; 95% CI, 0.44-0.89; high average: AOR, 0.67; 95% CI, 0.49-0.91 vs high educational level), shorter delay in initiating treatment after first onset (AOR, 0.98; 95% CI, 0.97-0.99), and medication received from a mental health specialist (AOR, 2.91; 95% CI, 2.04-4.15). Decomposition analysis showed that the first 2 of these 4 factors were associated with only the conditional probability of an individual treatment professional being perceived as helpful (age at first depression treatment: AOR, 1.02; 95% CI, 1.01-1.02; educational level: low: AOR, 0.48; 95% CI, 0.33-0.70; low-average: AOR, 0.62; 95% CI, 0.44-0.89; high-average: AOR, 0.67; 95% CI, 0.49-0.91 vs high educational level), whereas the latter 2 factors were associated with only persistence (treatment delay: AOR, 0.98; 95% CI, 0.97-0.99; treatment type: AOR, 3.43; 95% CI, 2.51-4.70).

CONCLUSIONS AND RELEVANCE

The probability that patients with MDD obtain treatment that they consider helpful might increase, perhaps markedly, if they persisted in help-seeking after unhelpful treatments with up to 9 prior professionals.

The epidemiology of alcohol use disorders cross-nationally: Findings from the World Mental Health Surveys

BACKGROUND

Prevalences of Alcohol Use Disorders (AUDs) and Mental Health Disorders (MHDs) in many individual countries have been reported but there are few cross-national studies. The WHO World Mental Health (WMH) Survey Initiative standardizes methodological factors facilitating comparison of the prevalences and associated factors of AUDs in a large number of countries to identify differences and commonalities.

METHODS

Lifetime and 12-month prevalence estimates of DSM-IV AUDs, MHDs, and associations were assessed in the 29 WMH surveys using the WHO CIDI 3.0.

RESULTS

Prevalence estimates of alcohol use and AUD across countries and WHO regions varied widely. Mean lifetime prevalence of alcohol use in all countries combined was 80%, ranging from 3.8% to 97.1%. Combined average population lifetime and 12-month prevalence of AUDs were 8.6% and 2.2% respectively and 10.7% and 4.4% among non-abstainers. Of individuals with a lifetime AUD, 43.9% had at least one lifetime MHD and 17.9% of respondents with a lifetime MHD had a lifetime AUD. For most comorbidity combinations, the MHD preceded the onset of the AUD. AUD prevalence was much higher for men than women. 15% of all lifetime AUD cases developed before age 18. Higher household income and being older at time of interview, married, and more educated, were associated with a lower risk for lifetime AUD and AUD persistence.

CONCLUSIONS

Prevalence of alcohol use and AUD is high overall, with large variation worldwide. The WMH surveys corroborate the wide geographic consistency of a number of well-documented clinical and epidemiological findings and patterns.

Somatic Experiencing for Posttraumatic Stress Disorder: A Randomized Controlled Outcome Study

This study presents the first known randomized controlled study evaluating the effectiveness of somatic experiencing (SE), an integrative body-focused therapy for treating people with posttraumatic stress disorder (PTSD). There were 63 participants meeting DSM-IV-TR full criteria for PTSD included. Baseline clinical interviews and self-report measures were completed by all participants, who were then randomly assigned to study (n = 33) or waitlist (n = 30) groups. Study participants began 15 weekly SE sessions, whereas waitlist participants waited the same period, after which the second evaluation was conducted. All participants were evaluated a third time after an additional 15 weeks, during which time the waitlist group received SE therapy. Pretreatment evaluation showed no significant differences between groups. Mixed model linear regression analysis showed significant intervention effects for posttraumatic symptoms severity (Cohen's d = 0.94 to 1.26) and depression (Cohen's d = 0.7 to 1.08) both pre-post and pre-follow-up. This randomized controlled study of SE shows positive results indicating SE may be an effective therapy method for PTSD. Further research is needed to understand who shall benefit most from this treatment modality.

Teaching mandibular implant-Supported overdentures in dental schools in North America - a survey

INTRODUCTION

Mandibular two-implant overdentures are considered the minimum standard of care for edentulous patients and provide an excellent performance, as well as satisfaction to the patients. Dental schools are required to promote the teaching of current treatment options in order to enable students to master state-of-the-art procedures.

AIMS

The purpose of this study was to examine how the theoretical and practical aspects of mandibular two-implant overdentures are taught in dental schools in North America.

METHODS

Data were collected via an online questionnaire that included questions regarding the theoretical and clinical courses, surgical procedure and imaging method.

RESULTS

Of 75 schools, 36 responded to the survey. Almost all the schools teach the subject theoretically, but it is not mandatory for students to perform in most of the schools. Only a minority (23%) of the mandibular dentures made by students are implant-supported. Almost all of the schools (94%) use two implants to support overdentures, and Locator abutment is used almost exclusively. The prevalent imaging for the surgical procedure is CT scans, although 30% of the schools use panoramic radiograph. None of the schools loads the implants immediately after surgery.

CONCLUSION

Some clear trends are apparent in the current survey: the use of two implants, no use of bar connectors and delayed loading of the implants. It is likely that graduates will not have sufficient clinical skills and will need continuing education to be familiar with the required procedures, both surgical and prosthetic.

Stability and Change in Posttraumatic Distress: A 7-Year Follow-Up Study of Mothers and Young Children Exposed to Cumulative Trauma

In situations of cumulative trauma, it is often unclear why some people remain resilient, whereas others experience distress, and how likely these responses are to change over time. To investigate the constancy of responses to cumulative trauma, stability and change in posttraumatic distress and resistance (as defined by no evidence of clinical symptoms) were assessed twice in 140 Israeli children and mothers exposed to continual rocket attacks over approximately 7 years, when the children were 2-4 (Time 1) and 9-11 years of age (Time 2). Measures included trauma exposure, posttraumatic and depressive symptoms, and child behavioral problems. We identified 4 longitudinal courses (LCs): resilient (resistance at Time 1 and Time 2), recovered (clinical distress at Time 1 and resistance at Time 2), developed symptoms (resistance at Time 1 and clinical distress at Time 2), and chronic distress (clinical distress at Time 1 and Time 2). Results showed more stability than change in the frequencies of resistance at both times of measurement. The resilient LC was the most common longitudinal course for both mothers and children. Multinomial regression models indicated that maternal posttraumatic symptoms predicted the recovered and chronic distress LCs of the children.

Detection and characterization of carbapenemase-producing Enterobacteriaceae in wounded Syrian patients admitted to hospitals in northern Israel

Since 2013, four hospitals in northern Israel have been providing care for Syrian nationals, primarily those wounded in the ongoing civil war. We analyzed carbapenemase-producing Enterobacteriaceae (CPE) isolates obtained from these patients. Isolate identification was performed using the VITEK 2 system. Polymerase chain reaction (PCR) was performed for the presence of bla KPC, bla NDM, and bla OXA-48. Susceptibility testing and genotyping were performed on selected isolates. During the study period, 595 Syrian patients were hospitalized, most of them young men. Thirty-two confirmed CPE isolates were grown from cultures taken from 30 patients. All but five isolates were identified as Klebsiella pneumoniae and Escherichia coli. Nineteen isolates produced NDM and 13 produced OXA-48. Among a further 29 isolates tested, multilocus sequence typing (MLST) showed that ST278 and ST38 were the major sequence types among the NDM-producing K. pneumoniae and OXA-48-producing E. coli isolates, respectively. Most were resistant to all three carbapenems in use in Israel and to gentamicin, but susceptible to colistin and fosfomycin. The source for bacterial acquisition could not be determined; however, some patients admitted to different medical centers were found to carry the same sequence type. CPE containing bla NDM and bla OXA-48 were prevalent among Syrian wounded hospitalized patients in northern Israel. The finding of the same sequence type among patients at different medical centers implies a common, prehospital source for these patients. These findings have implications for public health throughout the region.

The Effectiveness of Group Intervention on Enhancing Cognitive Emotion Regulation Strategies in Breast Cancer Patients: A 2-Year Follow-up

Purpose To evaluate the long-term effect of group intervention on enhancing cognitive emotion regulation (CER) strategies in female patients with early-stage breast cancer. Methods The sample included 174 patients who were diagnosed with early-to-mid stage breast cancer, completed adjuvant therapy, and agreed to fill out demographic and cognitive emotion regulation questionnaires (CERQ). About half of the patients (86, 49.4%) chose to participate in an 8-session group intervention (intervention group) while the others (88, 50.6%) did not (comparison group). The structured intervention for enhancing coping strategies with special emphasis on emotion regulation was conducted at the oncology unit at Rabin Medical Center by 2 experienced therapists. Preliminary effects on CER evaluated 6, 12, and 24 months postintervention were compared to the CER of a group of patients that opted not to participate in the group intervention. Results In the intervention group, the long-term effect (from baseline to 24 months) was assessed using the mix models module. Significant interaction effects were found for both the Negative CER scales (F(3, 268  ,404) = 3.66, P = .01) and for the Positive CER scales (F(3, 271  ,660) = 5.12, P = .002). No statistically significant differences in socio-demographic characteristics and medical variables were observed between the intervention and comparison groups. Conclusion Our findings indicate that a group intervention aimed at empowerment of coping strategies had positive long-term outcomes that reinforce adaptive coping strategies and improve less effective strategies of cognitive emotion regulation.

Posttraumatic Growth in Breast Cancer Survivors: Constructive and Illusory Aspects

This study investigated the impact of a building-resilience intervention on coping and posttraumatic growth (PTG) in a convenience sample of 94 breast cancer survivors. PTG was divided into constructive and illusory components, based on the two-sided Janus face model (Maercker & Zoellner, 2004). We operationalized constructive PTG as an improvement in both PTG and coping, and illusory PTG as an improvement in PTG only. An 8-session group intervention was delivered to 49 women (mean age = 51.5 years, SD = 10.7) who completed self-report questionnaires at baseline and at 6 months follow-up; a control group of 45 women only completed questionnaires. More than half the participants (n = 53; 56.38%) reported increased PTG at 6 months (mean change = 0.56, SD = 0.48, η(2) = .58). The increase in both PTG and positive coping was significantly greater in the intervention group than the control group (B = 0.23 for PTG, and B = 0.35 for positive coping). Further, a higher proportion of constructive PTG (vs. illusory PTG) was reported by the participants in the intervention group (89.3%), as compared to the control group (56.3%; z = 2.57). The distinction between constructive and illusory PTG has clinical implications for interventions promoting coping and growth among cancer survivors.

A novel anchoring system for colonic stents: a pilot in vivo study in a porcine model

BACKGROUND

Colorectal stents have a proven role in colorectal cancer as palliative care or a bridge to surgery. However, their efficacy and anchoring to the tissue varies according to stent design with stent migration rates up to 50 %. We present preliminary in vivo results of a new end-luminal anchoring system for stent fixation to the rectal canal. The aim was to assess the efficacy and safety of the stent using the anchoring system while subjecting the device to daily abdominal pressures related to daily activities in a porcine animal model.

METHODS

Ex vivo anatomical and physical studies were performed to improve the system's structure and safety. Four female pigs were followed for the acute and chronic (16 weeks) period. Two animals were euthanized and underwent en-bloc pelvic visceral excision and histopathological examination. Device fixation time, animal behavior, device patency, anoscopic examination and histopathological features were assessed.

RESULTS

Mean anchoring time was 13.83 weeks (standard error ± 1.38 weeks). One of the animals experienced early device expulsion with no complications. No obstruction was noted in any of the animals. Macroscopic examination revealed mild focal submucosal scarring in one animal and a normal examination in the other. Hematoxylin and eosin staining revealed mucosal ulceration and mixed inflammatory cell infiltrate, with no signs of granulomata, foreign body giant cell reaction or microabscess formation.

CONCLUSIONS

A novel fixation device designed for long-term intrarectal implantation was well tolerated and maintained anal canal patency without migration. Larger studies are needed before its implementation in humans.

Post anterior rectal resection syndrome--a retrospective multicentre study

AIM

The long-term effects of surgical and non-surgical factors on increased stool frequency and incontinence following anterior resection have been variably reported. We investigated the effects of surgical characteristics on symptoms at 1 month and more than 1 year postoperatively following anterior resection of the rectum.

METHOD

In this retrospective study of patients who underwent anterior resection of the rectum during 2002-2006, patients were interviewed regarding symptoms at 1 month and more than 1 year postoperatively. Anterior resection of the rectum syndrome (ARRS) is more simply defined as incontinence and/or frequent bowel movements after surgery and graded as severe, moderate or mild.

RESULTS

Of the 165 patients who underwent anterior resection for rectal cancer during the study period, 106 were included in the analysis. The median follow-up period was 3.4 years (range 13-72 months). ARRS had a high prevalence 1 month postoperatively (55.6%) but abated in over half the cases at 1 year postoperatively. The likelihood of development of early but not late ARRS was associated with the anastomotic level suggesting adaptation. ARRS and continence were unaffected by total mesorectal excision, the use of adjuvant radiation or chemotherapy, patient age or disease stage.

CONCLUSION

The level of anastomosis in anterior resection of the rectum had a significant effect on the prevalence of ARRS using a new simpler definition 1 month after surgery but not 1 year or more postoperatively. Further data on neorectal reservoir reconstruction using the simpler ARRS definition are required.

Low anterior resection syndrome (LARS): cause and effect and reconstructive considerations

Between 25 and 80% of patients undergoing a low or very low anterior resection will suffer postoperatively, from a constellation of symptoms including fecal urgency, frequent bowel movements, bowel fragmentation and incontinence, collectively referred to as the low anterior resection syndrome (LARS). The etiology of LARS is multifactorial with the potential of sphincter injury during anastomosis construction, alterations in anorectal physiology, the development of a pudendal neuropathy, and a lumbar plexopathy with exacerbation of symptoms if there is associated anastomotic sepsis or the use of adjuvant and neoadjuavnt therapies. The symptoms of LARS may be obviated in part by the construction of a neorectal reservoir which may take the form of a colonic J-pouch, a transverse coloplasty, or a side-to-end anastomosis. This review outlines the factors contributing to LARS symptomatology along with the short- and medium-term functional results of comparative trials with the different types of neorectal reconstructions.

Colorectal carcinoma in inflammatory bowel disease: a comparison between Crohn's and ulcerative colitis

AIM

The study assessed the clinicopathological features and survival rates of inflammatory bowel disease (IBD) patients with colorectal carcinoma (CRC), which accounts for ∼ 15% of all IBD associated death.

METHOD

The medical records of patients operated on for CRC in three institutions between 1992 and 2009 were reviewed, and those with Crohn's colitis (CC) and ulcerative colitis (UC) were identified. Data on age, gender, disease duration, colitis severity, surgical procedure, tumour stage and survival were retrieved.

RESULTS

Fifty-three patients (40 UC and 13 CC, 27 men, mean age at operation 54 years) were found. All parameters were comparable between the groups. Mean disease duration before CRC was 22.7 years for UC and 16.6 years for CC patients (P = 0.04). CRC was diagnosed preoperatively in 43 (81%) patients. Twenty-eight patients had colon cancer, 23 had rectal cancer and two patients had more than one cancer. All malignancies were located in segments with colitis. Over one-half were diagnosed at an advanced stage (36% stage III; 17% stage IV). At a mean follow up of 56 ± 65 months, 60% were alive (54% disease free) and 40% were dead from cancer-related causes. The 5-year survival rate was 61% for the UC and 37% for the CC patients (P = NS).

CONCLUSION

CRC in IBD patients is frequently diagnosed at an advanced stage, a factor that contributes to poor prognosis. The risk of CRC in CC patients is comparable to those with UC. Long-term surveillance is recommended for patients with long-standing CC and UC.

The effect of neoadjuvant Imatinib therapy on outcome and survival after rectal gastrointestinal stromal tumour

AIM

The study aimed to characterize the pathological and clinical response of rectal gastrointestinal stromal tumours (GISTs) to neoadjuvant Imatinib.

METHOD

The medical records of patients with rectal GISTs who were diagnosed and treated in five medical centres in Israel between January 2002 and January 2009 were retrospectively examined. Twelve patients who fulfilled the inclusion criteria of nonmetastatic rectal GIST for which preoperative neoadjuvant treatment with Imatinib was considered were suitable for enrollment.

RESULTS

Of the 12 patients, nine received neoadjuvant treatment with Imatinib. The three patients who had immediate surgery were excluded. There were five men and four women with a median age of 63 years and a median follow up of 32 months. All tumours were located in the lower two-thirds of the rectum. One patient had a complete clinical response, six had a partial response and two had stable disease. Seven patients subsequently underwent surgery; six had an R0 resection and one had an R1 resection. Three patients had recurrence. There was no disease-related mortality. The reduction in both tumour size and mitotic activity during preoperative Imatinib therapy was significant.

CONCLUSION

Preoperative Imatinib therapy can shrink large rectal GISTs, improving the chances of successful radical surgery and decreasing the risk of considerable morbidity.

Long-term outcome of loose seton for complex anal fistula: a two-centre study of patients with and without Crohn's disease

OBJECTIVE

Complex anal fistulas traverse a significant portion of the external sphincter muscle, making their treatment a surgical challenge. Several surgical options are used with conflicting results. The aim of this study was to analyse the results of permanent loose seton in the management of high anal fistulas in Crohn's disease (CD) patients and two-stage seton fistulotomy in patients without CD.

METHOD

We retrospectively reviewed the clinical records of 77 patients with complex anal fistula treated by loose seton over a 4-year period, in two medical centres. Recorded parameters included demographics, medical history, type of fistula, disease duration, previous surgery, morbidity, recurrence and mortality.

RESULTS

Sixty patients without CD underwent 107 fistula-related surgical procedures, and 17 CD patients underwent 29 procedures. Early postoperative complications were recorded in eight (10%) patients. Perioperative complications, mainly local sepsis or bleeding, were recorded in eight (10%) patients. Long-term complications were observed in nine non-CD and four CD patients. During a median follow-up period of 24 months, the recurrence rate was 40% in CD patients and 47% in patients without CD. Five patients (four non-CD patients and one CD patient) developed some degree of faecal incontinence.

CONCLUSION

The fistula recurrence rate following two-stage seton fistulotomy in non-CD patients was high. In CD patients the use of permanent loose seton is effective in controlling local sepsis in about half of patients and has low rates of subsequent incontinence.

Young-age onset of colorectal cancer in Israel

AIM

The study was conducted to investigate the differences in clinical-pathological, ethnic, and demographic presentations and the expression of mismatch repair proteins in a cohort of young-onset (</=50 years) versus late-onset Israeli patients (>50 years) with colorectal cancer.

MATERIALS AND METHODS

Clinical, demographic, and histopathological data of patients with colorectal cancer were collected retrospectively from medical records and pathology reports.

RESULTS

Ninety patients, 50 years of age or younger with a mean age of 42 years were compared with a group of 190 patients above 50 years of 50 (see Table 1). Sixty percent of the young-onset patients were females, compared to 40% in the older age group (P = 0.02). Twenty-one percent of the young-onset patients were Arabs as compared to 2% of older-onset patients (P = 0.001). Younger patients displayed a higher percentage of mucinous cancers and a higher percentage of diagnosis at an advanced stage of disease; 40% of young-onset versus 31% of older-onset patients presented Duke's stages C and D (P = 0.02).

CONCLUSIONS

Younger age of onset colorectal cancer in our cohort of Israeli patients is associated with higher percentage of Arab patients, mucinous cancers, female gender, and advanced stage at diagnosis.

Age-dependent spatial memory loss can be partially restored by immune activation

Aging is often associated with a decline in hippocampus-dependent spatial memory. Here, we show that functional cell-mediated immunity is required for the maintenance of hippocampus-dependent spatial memory. Sudden imposition of immune compromise in young mice caused spatial memory impairment, whereas immune reconstitution reversed memory deficit in immune-deficient mice. Analysis of hippocampal gene expression suggested that immune-dependent spatial memory performance was associated with the expression of insulin-like growth factor (Igf1) and of genes encoding proteins related to presynaptic activity (Syt10, Cplx2). We further showed that memory loss in aged mice could be attributed to age-related attenuation of the immune response and could be reversed by immune system activation. Homeostatic-driven proliferation of lymphocytes, which expands the existing T cell repertoire, restored spatial memory deficits in aged mice. Thus, our results identify a novel function of the immune system in the maintenance of spatial memory and suggest an original approach for arresting or reversing age-associated memory loss.

Effect of electrocautery vs. scalpel on fascial mechanical properties after midline laparotomy incision in rats

BACKGROUND

The method of midline laparotomy incision and closure remains a complex surgical problem.

OBJECTIVE

To compare the mechanical properties at the interface of midline laparotomy incision made by scalpel versus electrocuting current in rats.

METHODS

A sharp midline laparotomy incision was made in 60 Wistar female rats using a scalpel or electrocautery to open the fascia. The fascial and skin wounds were closed separately with a continuous nylon. Fascial specimens were analyzed for mechanical properties at the midline incision using a loading machine. The load-extension curve was recorded during tensile loading at a steady extension rate of 15 mm/min.

RESULTS

There was no statistically significant difference between the two groups in either wound-bursting force (PPEAK) or the strain energy spent until the point of measured PPEAK. Each load-extension curve showed a characteristic pattern in all rats. Tissue stiffness was greater in the scalpel group than in the electrocautery group (P = 0.02). Correlations were found between tissue stiffness and strain energy, between tissue stiffness and bursting force, and between bursting force and strain energy.

CONCLUSIONS

While tissue stiffness was greater when a scalpel was used compared to electrocuting to incise the midline abdominal fascia in rats, there was no difference in the bursting force required to disrupt the wound.

Telomeric protein Pin2/TRF1 as an important ATM target in response to double strand DNA breaks

ATM mutations are responsible for the genetic disease ataxia-telangiectasia (A-T). ATM encodes a protein kinase that is activated by ionizing radiation-induced double strand DNA breaks. Cells derived from A-T patients show many abnormalities, including accelerated telomere loss and hypersensitivity to ionizing radiation; they enter into mitosis and apoptosis after DNA damage. Pin2 was originally identified as a protein involved in G(2)/M regulation and is almost identical to TRF1, a telomeric protein that negatively regulates telomere elongation. Pin2 and TRF1, probably encoded by the same gene, PIN2/TRF1, are regulated during the cell cycle. Furthermore, up-regulation of Pin2 or TRF1 induces mitotic entry and apoptosis, a phenotype similar to that of A-T cells after DNA damage. These results suggest that ATM may regulate the function of Pin2/TRF1, but their exact relationship remains unknown. Here we show that Pin2/TRF1 coimmunoprecipitated with ATM, and its phosphorylation was increased in an ATM-dependent manner by ionizing DNA damage. Furthermore, activated ATM directly phosphorylated Pin2/TRF1 preferentially on the conserved Ser(219)-Gln site in vitro and in vivo. The biological significance of this phosphorylation is substantiated by functional analyses of the phosphorylation site mutants. Although expression of Pin2 and its mutants has no detectable effect on telomere length in transient transfection, a Pin2 mutant refractory to ATM phosphorylation on Ser(219) potently induces mitotic entry and apoptosis and increases radiation hypersensitivity of A-T cells. In contrast, Pin2 mutants mimicking ATM phosphorylation on Ser(219) completely fail to induce apoptosis and also reduce radiation hypersensitivity of A-T cells. Interestingly, the phenotype of the phosphorylation-mimicking mutants is the same as that which resulted from inhibition of endogenous Pin2/TRF1 in A-T cells by its dominant-negative mutants. These results demonstrate for the first time that ATM interacts with and phosphorylates Pin2/TRF1 and suggest that Pin2/TRF1 may be involved in the cellular response to double strand DNA breaks.

Emotional availability in the mother-infant dyad as related to the quality of infant-mother attachment relationship

Dyadic emotional availability and infant-mother attachment relationship were examined in 687 Israeli dyads. Concurrent assessments used the Strange Situation procedure (Ainsworth, Blehar, Waters, & Wall, 1978) for evaluating infants' attachment relationship, and the Emotional Availability Scales (Biringen, Robinson, & Emde, 1993) for evaluating the quality of mother-child interaction. It was found that higher scores on the Emotional Availability Scales were associated with infant attachment security. In addition, it was found that the Emotional Availability Scales discriminated between insecure-ambivalent and secure attachment classification, but were not informative about unique characteristics of emotional availability in dyads with avoidant and disorganized infants. Our findings contribute to the cross-cultural validation of Emotional Availability Scales against infants' attachment security.

Utilization of oriented peptide libraries to identify substrate motifs selected by ATM

The ataxia telangiectasia mutated (ATM) gene encodes a serine/threonine protein kinase that plays a critical role in genomic surveillance and development. Here, we use a peptide library approach to define the in vitro substrate specificity of ATM kinase activity. The peptide library analysis identified an optimal sequence with a central core motif of LSQE that is preferentially phosphorylated by ATM. The contributions of the amino acids surrounding serine in the LSQE motif were assessed by utilizing specific peptide libraries or individual peptide substrates. All amino acids comprising the LSQE sequence were critical for maximum peptide substrate suitability for ATM. The DNA-dependent protein kinase (DNA-PK), a Ser/Thr kinase related to ATM and important in DNA repair, was compared with ATM in terms of peptide substrate selectivity. DNA-PK was found to be unique in its preference of neighboring amino acids to the phosphorylated serine. Peptide library analyses defined a preferred amino acid motif for ATM that permits clear distinctions between ATM and DNA-PK kinase activity. Data base searches using the library-derived ATM sequence identified previously characterized substrates of ATM, as well as novel candidate substrate targets that may function downstream in ATM-directed signaling pathways.

Functional link of BRCA1 and ataxia telangiectasia gene product in DNA damage response

BRCA1 encodes a familial breast cancer suppressor that has a critical role in cellular responses to DNA damage. Mouse cells deficient for Brca1 show genetic instability, defective G2-M checkpoint control and reduced homologous recombination. BRCA1 also directly interacts with proteins of the DNA repair machinery and regulates expression of both the p21 and GADD45 genes. However, it remains unclear how DNA damage signals are transmitted to modulate the repair function of BRCA1. Here we show that the BRCA1-associated protein CtIP becomes hyperphosphorylated and dissociated from BRCA1 upon ionizing radiation. This phosphorylation event requires the protein kinase (ATM) that is mutated in the disease ataxia telangiectasia. ATM phosphorylates CtIP at serine residues 664 and 745, and mutation of these sites to alanine abrogates the dissociation of BRCA1 from CtIP, resulting in persistent repression of BRCA1-dependent induction of GADD45 upon ionizing radiation. We conclude that ATM, by phosphorylating CtIP upon ionizing radiation, may modulate BRCA1-mediated regulation of the DNA damage-response GADD45 gene, thus providing a potential link between ATM deficiency and breast cancer.

Identification of ATM mutations using extended RT-PCR and restriction endonuclease fingerprinting, and elucidation of the repertoire of A-T mutations in Israel

Ataxia-telangiectasia (A-T) is an autosomal recessive disorder characterized by neurodegeneration, immunodeficiency, cancer predisposition, and radiation sensitivity. The responsible gene, ATM, has an extensive genomic structure and encodes a large transcript with a 9.2 kb open reading frame (ORF). A-T mutations are extremely variable and most of them are private. We streamlined a high throughput protocol for the search for ATM mutations. The entire ATM ORF is amplified in a single RT-PCR step requiring a minimal amount of RNA. The product can serve for numerous nested PCRs in which overlapping portions of the ORF are further amplified and subjected to restriction endonuclease fingerprinting (REF) analysis. Splicing errors are readily detectable during the initial amplification of each portion. Using this protocol, we identified 5 novel A-T mutations and completed the elucidation of the molecular basis of A-T in the Israeli population.

Functional link between ataxia-telangiectasia and Nijmegen breakage syndrome gene products

Ataxia-telangiectasia (A-T) and Nijmegen breakage syndrome (NBS) are recessive genetic disorders with susceptibility to cancer and similar cellular phenotypes. The protein product of the gene responsible for A-T, designated ATM, is a member of a family of kinases characterized by a carboxy-terminal phosphatidylinositol 3-kinase-like domain. The NBS1 protein is specifically mutated in patients with Nijmegen breakage syndrome and forms a complex with the DNA repair proteins Rad50 and Mrel1. Here we show that phosphorylation of NBS1, induced by ionizing radiation, requires catalytically active ATM. Complexes containing ATM and NBS1 exist in vivo in both untreated cells and cells treated with ionizing radiation. We have identified two residues of NBS1, Ser 278 and Ser 343 that are phosphorylated in vitro by ATM and whose modification in vivo is essential for the cellular response to DNA damage. This response includes S-phase checkpoint activation, formation of the NBS1/Mrel1/Rad50 nuclear foci and rescue of hypersensitivity to ionizing radiation. Together, these results demonstrate a biochemical link between cell-cycle checkpoints activated by DNA damage and DNA repair in two genetic diseases with overlapping phenotypes.

Structured triacylglycerol emulsion, containing both medium- and long-chain fatty acids, in long-term home parenteral nutrition: a double-blind randomized cross-over study

Structured lipid emulsion, an innovative approach in which both medium-chain and long-chain fatty acids are esterified to the same glycerol backbone, has been recently shown to be a safe and efficient way of providing energy to patients requiring parenteral nutrition. As yet, no assessment has been made of its safety and effect on liver functions during long-term treatment. Twenty-two home parenteral nutrition patients with Crohn's disease or short bowel syndrome were enrolled in a double-blind randomized, cross-over study. Twenty patients who completed the study were treated for 4 wk with a structured lipid emulsion and for 4 wk with long-chain triacylglycerol emulsion. Determined every 1 or 2 wk were blood pressure, body weight, respiratory rate, blood count, liver functions, albumin, transferrin, plasma lipids, free fatty acids (FFAs), and, at the end of each treatment period (weeks 4 and 8), plasma dicarboxylic acids and 3-OH-fatty acids. No differences were observed between the groups or within the groups between the two treatments with respect to either clinical safety and adverse event occurrence or laboratory assessments. Plasma dicarboxylic acids and 3-OH-fatty acids were similar and within normal range. No alteration of liver function occurred in any of the patients treated with the structured lipid emulsion, whereas two of the patients receiving long-chain triaclyglycerol emulsion developed abnormal liver function, which resolved after switching to the structured lipid emulsion. In conclusion, structured triacylyglycerols containing both medium- and long-chain fatty acids appear to be safe and well tolerated on a long-term basis in patients on home parenteral nutrition, and it may be associated with possible reduction in liver dysfunction.

Diverticulitis: the effect of age and location on the course of disease

To examine the effect of patient's age and the location of diverticular disease on the course of the acute disease we retrospectively collected demographic data, symptoms, laboratory findings, imaging techniques, type of treatment (conservative vs. surgical), early and late complications, and follow-up data on 119 patients with acute diverticulitis (74 women, 45 men; mean age 64+/-14 years; follow-up 7-102 months, median 40). Patients were divided by their age into two groups (42 aged 60 years or younger, 77 aged over 60) and on the location of their disease (108 to the left of the middle transverse, 11 to the right). Lower abdominal pain, abdominal tenderness, and fever were the most common complaints (70-97%). In the younger patients we found a significantly greater preponderance in the right colon (P = 0.02) than in older patients. Abdominal abscesses and fistulas were more common in right-sided diverticulitis (P = 0.01). Patients with right-sided colon diverticulitis were treated surgically (82%) and on an emergency basis more often than patients with left-side colon diverticulitis (25%; P = 0.001). Older patients treated conservatively suffered more than younger patients (61% and 33% respectively; P = 0.04) from recurrent abdominal pain but not from recurrent, confirmed diverticulitis. Patients with right-sided diverticulitis treated conservatively suffered more from recurrent diverticulitis episodes than patients with left-sided diverticulitis (P = 0.05). Younger patients thus do not have a more aggressive form of diverticulitis than older patients. Patients with acute diverticulitis in the right colon are likely to be operated earlier and for mistaken diagnoses than patients with left-sided diverticulitis.

Emotional availability and attachment representations in kibbutz infants and their mothers

Three components of the attachment transmission model were examined in 48 kibbutz dyads from 2 kibbutz sleeping arrangements: communal and home-based. Concurrent assessments used the Strange Situation procedure (M. D. Ainsworth, M. C. Blehar, E. Waters, & S. Wall, 1978) for infants' attachment relations, the Adult Attachment Interview (C. George, N. Kaplan, & M. Main, 1985) for mothers' attachment representations, and the Emotional Availability Scales (Z. Biringen, J. L. Robinson, & R. N. Emde, 1993) for emotional availability in the dyads. Security of infants' attachment relations as well as autonomy of mothers' attachment representations were associated with higher emotional availability scores. In addition, significantly poorer emotional availability was found in dyads in which infants were insecurely attached and mothers were nonautonomous. Results also indicate that in the ecology of collective sleeping, the associations between the experience of emotional availability in the dyads and infants' and mothers' attachment may have been disrupted.

Targeting double-strand breaks to replicating DNA identifies a subpathway of DSB repair that is defective in ataxia-telangiectasia cells

The critical cellular defect(s) and basis for cell killing by ionizing radiation in ataxia-telangiectasia (A-T) are unknown. We use the topoisomerase I inhibitor camptothecin (CPT), which kills mainly S-phase cells and induces DSBs predominantly in replication forks, to show that A-T cells are defective in the repair of this particular subclass of DSBs. CPT-treated A-T cells reaching G2 have abnormally high levels of chromatid exchanges (viewed as prematurely condensed G2 chromosomes); aberrations in normal cells are mostly chromatid breaks. Transfectants of A-T cells with the wild-type ATM cDNA are corrected for CPT sensitivity, chromatid aberrations, and the DSB repair defect. These data suggest that in normal cells ATM, the A-T protein, probably recognizes DSBs in active replicons and targets the repair machinery to the breaks; in addition, the ATM protein is involved in the suppression of low-fidelity, adventitious rejoining between replication-associated DSBs. The loss of ATM functions therefore leads to genome destabilization, sensitivity to DSB-inducing agents and to the cancer-promoting illegitimate exchange events that follow.

Emotional availability and attachment representations in kibbutz infants and their mothers

Three components of the attachment transmission model were examined in 48 kibbutz dyads from 2 kibbutz sleeping arrangements: communal and home-based. Concurrent assessments used the Strange Situation procedure (M. D. Ainsworth, M. C. Blehar, E. Waters, & S. Wall, 1978) for infants' attachment relations, the Adult Attachment Interview (C. George, N. Kaplan, & M. Main, 1985) for mothers' attachment representations, and the Emotional Availability Scales (Z. Biringen, J. L. Robinson, & R. N. Emde, 1993) for emotional availability in the dyads. Security of infants' attachment relations as well as autonomy of mothers' attachment representations were associated with higher emotional availability scores. In addition, significantly poorer emotional availability was found in dyads in which infants were insecurely attached and mothers were nonautonomous. Results also indicate that in the ecology of collective sleeping, the associations between the experience of emotional availability in the dyads and infants' and mothers' attachment may have been disrupted.

Embolization--an optional treatment for intractable hemorrhage from a malignant rectovaginal fistula: report of a case

PURPOSE

Patients rarely have intractable hemorrhage from rectovaginal fistulas, which usually require surgical intervention. This report presents our experience with nonsurgical treatment of a high-risk patient with uncontrolled hemorrhage originating from a malignant rectovaginal fistula.

METHODS

A 74-year-old female developed uncontrolled hemorrhage from a malignant rectovaginal fistula. Because of her poor physical condition, an embolization with metal clips of the right and left hypogastric arteries was performed, distal to the superior gluteal artery.

RESULTS

Embolization was successful in controlling the rectovaginal bleeding, allowing the patient to live 12 months. She refused adjuvant radiotherapy or chemotherapy.

CONCLUSIONS

Selective angiography and embolization is a worthwhile alternative in patients with uncontrolled bleeding from a malignant rectovaginal fistula who are poor candidates for surgical intervention.

Defective potassium currents in ataxia telangiectasia fibroblasts

Similarities exist between the progressive cerebellar ataxia in ataxia telangiectasia (AT) patients and a number of neurodegenerative diseases in both mouse and man involving specific mutations in ion channels and/or ion channel activity. These relationships led us to investigate the possibility of defective ion channel activity in AT cells. We examined changes in the membrane potential of AT fibroblasts in response to extracellular cation addition and found that the ability of AT fibroblasts to depolarize in response to increasing concentrations of extracellular K+ is significantly reduced when compared with control fibroblasts. Electrophysiological measurements performed with a number of AT cell lines, as well as two matched sets of primary AT fibroblast cultures, reveal that outward rectifier K+ currents are largely absent in AT fibroblasts in comparison with control cells. These K+ current defects can be corrected in AT fibroblasts transfected with the full-length ATM cDNA. These data implicate, for the first time, a role for ATM in the regulation of K+ channel activity and membrane potential.

Enhanced phosphorylation of p53 by ATM in response to DNA damage

The ATM protein, encoded by the gene responsible for the human genetic disorder ataxia telangiectasia (A-T), regulates several cellular responses to DNA breaks. ATM shares a phosphoinositide 3-kinase-related domain with several proteins, some of them protein kinases. A wortmannin-sensitive protein kinase activity was associated with endogenous or recombinant ATM and was abolished by structural ATM mutations. In vitro substrates included the translation repressor PHAS-I and the p53 protein. ATM phosphorylated p53 in vitro on a single residue, serine-15, which is phosphorylated in vivo in response to DNA damage. This activity was markedly enhanced within minutes after treatment of cells with a radiomimetic drug; the total amount of ATM remained unchanged. Various damage-induced responses may be activated by enhancement of the protein kinase activity of ATM.

ATM binds to beta-adaptin in cytoplasmic vesicles

Inherited mutations in the ATM gene lead to a complex clinical phenotype characterized by neuronal degeneration, oculocutaneous telangiectasias, immune dysfunction, and cancer predisposition. Using the yeast two-hybrid system, we demonstrate that ataxia telangiectasia mutated (ATM) binds to beta-adaptin, one of the components of the AP-2 adaptor complex, which is involved in clathrin-mediated endocytosis of receptors. The interaction between ATM and beta-adaptin was confirmed in vitro, and coimmunoprecipitation and colocalization studies show that the proteins also associate in vivo. ATM also interacts in vitro with beta-NAP, a neuronal-specific beta-adaptin homolog that was identified as an autoantigen in a patient with cerebellar degeneration. Our data describing the association of ATM with beta-adaptin in vesicles indicate that ATM may play a role in intracellular vesicle and/or protein transport mechanisms.

Recombinant ATM protein complements the cellular A-T phenotype

Ataxia-telangiectasia (A-T) is an autosomal recessive disorder characterized by neurodegeneration, immunodeficiency, cancer predisposition, genome instability and radiation sensitivity. The cellular phenotype of A-T points to defects in signal transduction pathways involved in activation of cell cycle checkpoints by free radical damage, and other pathways that mediate the transmission of specific mitogenic stimuli. The product of the responsible gene, ATM, belongs to a family of large proteins that contribute to maintaining genome stability and cell cycle progression in various organisms. A recombinant vector that stably expresses a full-length ATM protein is a valuable tool for its functional analysis. We constructed and cloned a recombinant, full-length open reading frame of ATM using a combination of vectors and hosts that overcame an inherent instability of this sequence. Recombinant ATM was stably expressed in insect cells using a baculovirus vector, albeit at a low level, and in human A-T cells using an episomal expression vector. An amino-terminal FLAG epitope added to the protein allowed highly specific detection of the recombinant molecule by immunoblotting, immunoprecipitation and immunostaining, and its isolation using immunoaffinity. Similar to endogenous ATM, the recombinant protein is located mainly in the nucleus, with low levels in the cytoplasm. Ectopic expression of ATM in A-T cells restored normal sensitivity to ionizing radiation and the radiomimetic drug neocarzinostatin, and a normal pattern of post-irradiation DNA synthesis, which represents an S-phase checkpoint. These observations indicate that the recombinant, epitope-tagged protein is functional. Introduction into this molecule of a known A-T missense mutation, Glu2904Gly, resulted in apparent instability of the protein and inability to complement the A-T phenotype. These findings indicate that the physiological defects characteristic of A-T cells result from the absence of the ATM protein, and that this deficiency can be corrected by ectopic expression of this protein.

The ataxia-telangiectasia gene product, a constitutively expressed nuclear protein that is not up-regulated following genome damage

The product of the ataxia-telangiectasia gene (ATM) was identified by using an antiserum developed to a peptide corresponding to the deduced amino acid sequence. The ATM protein is a single, high-molecular weight protein predominantly confined to the nucleus of human fibroblasts, but is present in both nuclear and microsomal fractions from human lymphoblast cells and peripheral blood lymphocytes. ATM protein levels and localization remain constant throughout all stages of the cell cycle. Truncated ATM protein was not detected in lymphoblasts from ataxia-telangiectasia patients homozygous for mutations leading to premature protein termination. Exposure of normal human cells to gamma-irradiation and the radiomimetic drug neocarzinostatin had no effect on ATM protein levels, in contrast to a noted rise in p53 levels over the same time interval. These findings are consistent with a role for the ATM protein in ensuring the fidelity of DNA repair and cell cycle regulation following genome damage.