Progression of Geographic Atrophy: Retrospective Analysis of Patients from the IRIS® Registry (Intelligent Research in Sight)

Purpose

To evaluate disease progression and associated vision changes in patients with geographic atrophy (GA) secondary to age-related macular degeneration (AMD) in 1 eye and GA or neovascular AMD (nAMD) in the fellow eye using a large dataset from routine clinical practice.

Design

Retrospective analysis of clinical data over 24 months.

Subjects

A total of 256 635 patients with GA from the American Academy of Ophthalmology (Academy) IRIS® Registry (Intelligent Research in Sight) Registry (January 2016 to December 2017).

Methods

Patients with ≥ 24 months of follow-up were grouped by fellow-eye status: Cohort 1, GA:GA; Cohort 2, GA:nAMD, each with (subfoveal) and without subfoveal (nonsubfoveal) involvement. Eyes with history of retinal disease other than AMD were excluded. Sensitivity analysis included patients who were managed by retina specialists and had a record of imaging within 30 days of diagnosis.

Main Outcome Measures

Change in visual acuity (VA), occurrence of new-onset nAMD, and GA progression from nonsubfoveal to subfoveal.

Results

In total, 69 441 patients were included: 44 120 (64%) GA:GA and 25 321 (36%) GA:nAMD. Otherwise eligible patients (57 788) were excluded due to follow-up < 24 months. In both GA:GA and GA:nAMD cohorts, nonsubfoveal study eyes had better mean (standard deviation) VA at index (67 [19.3] and 66 [20.3] letters) than subfoveal eyes (59 [23.9] and 47 [26.9] letters), and 24-month mean VA changes were similar for nonsubfoveal (-7.6 and -6.2) and subfoveal (-7.9 and -6.5) subgroups. Progression to subfoveal GA occurred in 16.7% of nonsubfoveal study eyes in the GA:GA cohort and 12.5% in the GA:nAMD cohort. More new-onset study-eye nAMD was observed in the GA:nAMD (21.6%) versus GA:GA (8.2%) cohorts. Sensitivity analysis supported the robustness of the observations in the study.

Conclusions

This retrospective analysis describes the natural progression of GA lesions and the decline in VA associated with the disease.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Identifying the mechanism of missingness for unspecified diabetic retinopathy disease severity in the electronic health record: an IRIS® Registry analysis

Observational studies of diabetic retinopathy (DR) using electronic health record data often determine disease severity using International Classification of Disease (ICD) codes. We investigated the mechanism of missingness for DR severity based on ICD coding using the American Academy of Ophthalmology IRIS® Registry. We included all patient encounters in the registry with a DR ICD-9 or ICD-10 code between January 1, 2014 and June 30, 2021. Demographic, clinical, and practice-level characteristics were compared between encounters with specified and unspecified disease severity. Practices were divided into quartiles based on the proportion of clinical encounters with unspecified DR severity. Encounters with unspecified disease severity were associated with significantly older patient age, better visual acuity, and lower utilization of ophthalmic procedures. Higher volume practices and retina specialist practices had lower proportions of clinical encounters with unspecified disease severity. Results strongly suggest that DR disease severity related to ICD coding is missing not at random.

Use of Latent Class Analysis and k-Means Clustering to Identify Complex Patient Profiles

IMPORTANCE

Medically complex patients are a heterogeneous group that contribute to a substantial proportion of health care costs. Coordinated efforts to improve care and reduce costs for this patient population have had limited success to date.

OBJECTIVE

To define distinct patient clinical profiles among the most medically complex patients through clinical interpretation of analytically derived patient clusters.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study analyzed the most medically complex patients within Kaiser Permanente Northern California, a large integrated health care delivery system, based on comorbidity score, prior emergency department admissions, and predicted likelihood of hospitalization, from July 18, 2018, to July 15, 2019. From a starting point of over 5000 clinical variables, we used both clinical judgment and analytic methods to reduce to the 97 most informative covariates. Patients were then grouped using 2 methods (latent class analysis, generalized low-rank models, with k-means clustering). Results were interpreted by a panel of clinical stakeholders to define clinically meaningful patient profiles.

MAIN OUTCOMES AND MEASURES

Complex patient profiles, 1-year health care utilization, and mortality outcomes by profile.

RESULTS

The analysis included 104 869 individuals representing 3.3% of the adult population (mean [SD] age, 70.7 [14.5] years; 52.4% women; 39% non-White race/ethnicity). Latent class analysis resulted in a 7-class solution. Stakeholders defined the following complex patient profiles (prevalence): high acuity (9.4%), older patients with cardiovascular complications (15.9%), frail elderly (12.5%), pain management (12.3%), psychiatric illness (12.0%), cancer treatment (7.6%), and less engaged (27%). Patients in these groups had significantly different 1-year mortality rates (ranging from 3.0% for psychiatric illness profile to 23.4% for frail elderly profile; risk ratio, 7.9 [95% CI, 7.1-8.8], P < .001). Repeating the analysis using k-means clustering resulted in qualitatively similar groupings. Each clinical profile suggested a distinct collaborative care strategy to optimize management.

CONCLUSIONS AND RELEVANCE

The findings suggest that highly medically complex patient populations may be categorized into distinct patient profiles that are amenable to varying strategies for resource allocation and coordinated care interventions.

Abstract 173: Effect of a Regional Telestroke Program on Door-to-Needle Time and Clinical Outcomes

Background: Published data suggest that the faster acute stroke patients are treated with IV alteplase the better they do post discharge. Telestroke allows community hospitals to access stroke expertise in the management of acute stroke patients. In a real-world practice setting, we assessed the influence of a regional standardized telestroke program among community hospitals on door-to-needle (DTN) time and clinical outcomes.

Methods: In January 2016, a new standardized acute telestroke program for 21 stroke centers in an integrated healthcare system was launched. It included immediate evaluation by a stroke neurologist via video, an expedited IV alteplase treatment program, rapid CT angiographic investigation, and expedited transfer and treatment for patients with large vessel occlusion. We compared patient characteristics, DTN times, length of stay (LOS), discharge outcomes, and 90-day mortality between those treated with IV alteplase pre- (July 2013 to June 2015) to post-telestroke program (January 2016 to December 2017).

Results: Post-implementation of the telestroke program, more patients were treated with alteplase (Table). Median DTN time and LOS were shorter. A greater percentage of patients were discharged home (57.3% in post-telestroke vs. 12.1% in pre, p<0.001). In-hospital mortality was higher in post-telestroke compared to pre. However, symptomatic hemorrhage rates were not significantly different, at 4.5% in 2014 pre-EXPRESS, 4.3% in 2016 and 3.2% in 2017 post-EXPRESS. In addition, 90-day mortality was not different between pre- and post-telestroke (Table).

Conclusions: Implementation of a regional standardized telestroke program in a community setting increased utilization of alteplase, improved DTN time, decreased length of stay and significantly increased the chances of patients going home. Further analyses are needed to understand the significant contributing factors to the success of this program.

Abstract 175: Kaiser Stroke Express Program - Population Based Estimate of Potential Accuracy of Field Based Identification of Endovascular Treatment Candidates

Background: Whether patients with acute stroke and large vessel occlusion (LVO) may benefit from prehospital identification and diversion by EMS to a center offering endovascular therapy (EST) is controversial. The accuracy of prehospital scales as predictors of LVO is only one feature of whether EMS can effectively identify patients suitable for EST. Other factors include accuracy of last known well time (LTKW) and identification of stroke mimics. We performed a population-based estimate of potential accuracy of field based identification of potential EST candidates in a large community setting.

Methods: In Kaiser Permanente Northern California, all acute stroke patients arriving at its 19 primary stroke centers (PSC) between 7am and 12am were evaluated on arrival by stroke neurologists by video. We reviewed the teleneurology notes to determine the potential accuracy of EST selection based on NIHSS score > 7.

Results: For 2016, there were 2546 total potential stroke alerts triaged by EMS as having potential acute strokes [Figure]. Of these, 1268 (50%) were not candidates for acute stroke treatment for various reasons including stroke mimics and inaccurate LTKW. Out of 1241 cases deemed candidates for acute stroke treatment, 638 (25.1%) had potential LVO based on NIHSS > 7. Of these, 116 (4.6% of total “potential strokes” and 18.2% of patients who had “severe” strokes) were diagnosed with LVO and treated with EST.

Conclusions: Even if field based tools were as accurate as clinical scoring by stroke neurologists, less than 1 in 4 patients diverted to endovascular stroke centers and away from closer PSC would benefit by receiving EST. Given that 50% of patients triaged by EMS did not qualify for any acute stroke treatment, a lower percentage of patients would actually benefit from field based diversion. Stroke systems may be better served by focusing on rapid treatment, evaluation, and transfer to endovascular centers than field based diversion strategies.

Abstract WP67: Outcomes in the Elderly Post-alteplase Treatment in a Community Setting

Background: Risks and benefits of acute thrombolysis in elderly stroke patients remained unclear, especially in those aged ≥90 years. We evaluated the safety of thrombolysis in the elderly in a large integrated healthcare system.

Methods: In 2016, Kaiser Permanente Northern California (KPNC) launched a new standardized acute telestroke care workflow for all 21 stroke centers. It included immediate evaluation by a stroke neurologist via video, an expedited IV alteplase treatment program, rapid CT angiographic investigation, and expedited transfer and treatment for patients with large vessel occlusion (LVO). We compared patient characteristics, door-to-needle (DTN) times and symptomatic intracranial hemorrhage (sICH) rates between those treated with IV alteplase aged <80 to those 80-89 to those ≥90 years. Multivariable logistic regression model accounting for within hospital clustering was used to assess whether being ≥90 years was associated with a poorer outcome.

Results: For 2016, our Telestroke program gave IV alteplase to 646 KP members [Table]. The oldest subgroup had a higher percentage of female and higher rates of vascular risk factors. They were more likely to arrive by EMS, to have a higher initial NIHSS and to have a LVO. Average DTN times were not different between the three age groups. There were no differences in the rates of sICH and length of stay. The in-hospital mortality rate was higher in the elderly, possibly due to higher rates of comorbidities. In multivariable model, after adjusting for demographics, co-morbidities, EMS arrival, sICH, NIHSS, and DTN, being elderly did not affect the likelihood of being discharged home post-thrombolysis (OR=0.56, 95% CI 0.29-1.07, p=0.08).

Conclusions: In a large community setting with a standardized approach to acute stroke treatment, our data supported IV alteplase use in elderly patients. It is important to consider pre-stroke disability when deciding on thrombolysis in the elderly.

Abstract 186: Longer Term Effect of Lifestyle Intervention on Blood Pressure Control Among African Americans: One Year Follow-up of Shake, Rattle & Roll Trial

Background: In Kaiser Permanente Northern California (KPNC), an integrated healthcare system with a high overall hypertension (HTN) control rate, blacks still had poorer blood pressure (BP) control than whites. The “Shake, Rattle and Roll” (SRR) trial is named for: 1) “shake” the salt habit; 2) “rattle” the intensity of current BP management; and 3) adapt and “roll” out the interventions to other communities. Successful lifestyle (LS) interventions tend to be short-lived. We evaluated the effect of LS intervention in SRR on BP control at 12 months after the trial ended.

Methods: SRR is a pragmatic cluster-randomized controlled trial conducted at Kaiser Oakland. All PCPs and their panels of black patients were randomized, stratified by panel size, to one of 3 arms: 1) usual care (UC); or 2) enhanced monitoring (EM) of KPNC BP management protocol; or 3) culturally tailored LS coaching focused on the DASH eating plan. Black patients from KPNC HTN Registry with a persistent high BP reading ≥ 140/90 qualified to be recruited into SRR. The intervention period lasted 12 months followed by 15 months of data collection with no participant contact. We assessed BP control rates using the latest follow-up BP measurements between enrollment and 27 months post-enrollment. Data on demographics and medications were collected from participants’ EMRs.

Results: We randomized 98 PCPs. There were 1,129 enrolled in UC, 346 in EM and 286 in LS. Median age was 61 years. At the end of 12 months post-intervention, BP control rates were higher in LS than in UC (73.2% vs. 60.6%, p<0.001; Table). There was no difference across arms for adherence to BP medications, change in weight, or outpatient primary care utilization.

Conclusions: Participants in LS arm continued to have better BP control than UC at 12 months after intervention ended in SRR. The sustainability of a culturally appropriate LS intervention with a focus on DASH should be studied further for implementation in adults with uncontrolled HTN.

Abstract TMP8: Predictors of Large Vessel Occlusion in Kaiser Stroke EXPRESS Program

Background: In 2015, trials showed that rapid endovascular stroke treatment (EST) of qualified patients with large vessel occlusion (LVO) resulted in improved outcomes over treatment with IV tPA alone. In 2015, Kaiser Permanente Northern California (KPNC) redesigned its acute stroke care work flow for its 21 stroke centers, which included expedited IV t-pa treatment, rapid CTA investigation, expedited transfer of appropriate patients for EST. We assessed for predictors of LVO post-implementation.

Methods: The KPNC Stroke EXPRESS program was live in all centers by January 2016. Using clinical data for 1/1/16 - 7/10/16, we evaluated the frequency and locations of LVO, and patient characteristics of those with LVO. Multivariate logistic regression was used to examine whether age, gender, race, or an NIHSS ≥ 8 are predictors of LVO.

Results: There were 2,204 tele-stroke alert cases from the ED. Among 993 (39.3%) that proceeded as likely acute stroke, 812 (81.8%) were evaluated with CTA. Out of those who had a CTA, 152 (18.7%) were found to have LVO as followed: 27 (17.8%) ICA, 87 (57.2%) M1, 24 (15.8%) M2, 6 (4.0%) basilar, 5 (3.3%) PCA, and 3 (2.0%) vertebral. Of those with LVO, 97 (63.8%) were treated with EST. Patients with LVO had a higher median NIHSS (15 vs. 5 in those without LVO). Neglect (27% vs. 7%) and gaze deviation (16% vs. 1%) were more likely to be seen among those with LVO and treated with EST compared to those without LVO. In multivariate analysis, age (OR=1.02, 95% CI 1.00 - 1.03, p=0.01) and NIHSS ≥8 (OR = 4.99, 95% CI 3.32- 7.49, p < 0.001) were associated with LVO. PPV for NIHSS ≥8 was 75.7%.

Conclusions: In our large multi-ethnic population of acute stroke patients, a relatively small percentage (19%) was found to have LVO and only a subset qualified for EST. Predictors of LVO included NIHSS ≥8, increasing age, and presence of neglect and gaze preference. Given the low numbers of patients brought in for acute stroke treatment who ended up with a LVO requiring EST, further research is needed to assess a given system’s ability to rapidly evaluate and transfer as appropriate for EST rather than paramedic based diversion.

Abstract 88: No Disparities in Acute Stroke Treatment in Kaiser Stroke EXPRESS Program

Background: Prior published studies reported disparities in timely treatment with tPA for stroke patients who were older, African American or female. In 2015, Kaiser Permanente Northern California (KPNC) redesigned its acute stroke care work flow for the entire region, which included immediate evaluation by a stroke neurologist via video, an expedited IV tPA treatment program, rapid CT angiographic investigation, and expedited transfer of appropriate patients with large vessel occlusion (LVO) for endovascular stroke treatment (EST). We sought to evaluate whether disparities exist in acute stroke treatment within the redesigned process.

Methods: KPNC is an integrated health care system with 21 certified stroke centers serving 3.9+ millions members. All centers implemented the new program by January 2016. Using clinical data from 1/1/16 to 7/10/16, we evaluated the frequency of IV tPA administration by gender, race, and age groups after implementation of the new process. We performed multivariate analysis with age, gender, race-ethnicity, Kaiser membership, mode of ED arrival (by ambulance vs. private transportation) to assess for any disparities in achieving DTN time.

Results: Post implementation, we found no significant differences in the rates of IV t-pa administration in eligible patients based on race, gender, age category (<40 years, 40-64, 65-79, ≥80), Kaiser membership, or mode of ED arrival. In multivariate analysis for factors influencing DTN time, no differences were seen for DTN time <60 minutes. Age (OR=1.02, 95% CI 1.00-1.03, p=0.03) and arrival by ambulance (OR=5.01, 95% CI 3.01-8.60, p<0.001) were associated with a faster DTN time of <30 minutes.

Conclusions: Thus far, we have found no disparities in the use of IV tPA or DTN time for a large integrated healthcare system after implementation of the Stroke EXPRESS program. A consistent standardized approach to acute stroke care may help to reduce disparities on the basis of race, gender, age, or even membership in healthcare system.

Abstract TP259: Accuracy of EMS Identification of Acute Strokes Eligible for tPA Treatment in Kaiser Stroke EXPRESS Program

Background: Field-based diversion for potential stroke patients who may qualify for endovascular stroke therapy (EST) has been proposed more widely in 2015. In 2015, Kaiser Permanente Northern California (KPNC) redesigned its acute stroke care work flow for all its 21 stroke centers, which included rapid evaluation of all stroke alerts by a stroke neurologist via teleneurology. We investigated the accuracy of EMS-activated stroke alerts.

Methods: From 1/1/16 to 7/10/16, all acute strokes presenting to an ED between 7 AM and midnight were assessed upon arrival by a teleneurologist. We reviewed all telestroke cases to determine the frequency of tPA given, cancelled stroke alerts, and the reasons for not treating with IV t-PA, particularly among ambulance arrivals. Multivariate logistic regression was used to assess age, gender, race, Kaiser membership, and mode of ED arrival as predictors of stroke alert cancellation.

Results: There were 2192 stroke alerts activated. Of these, 1332 (60.7%) arrived by EMS and 860 (39.2%) by non-EMS transport. Of patients arriving by EMS, 651 (48.9%) were cancelled and deemed ineligible for IV t-PA. Most common reasons for cancellation were: last time known well (LTKW) out of range (23%), stroke mimic (33%), symptom resolution (19%), new data regarding goals of care (2%), and other (22.5%). The remaining 681 (51.1%) ambulance arrivals were potential candidates for IV tPA. Subsequently, 334 (50.4%) of them received tPA. Reasons for tPA not given included subsequent resolution of symptoms, concerning CT findings (such as bleed), INR>1.7 in patients on warfarin, further information clarifying time of onset. Among those who arrived by EMS and received IV t-PA, all had CTA and 103 (30.8%) were found to have a large vessel occlusion and 74 (71.8%) underwent EST. In multivariate analysis for all cancelled stroke alerts, arrival by non-EMS transport (OR=1.74, 95% CI 1.44-2.10, p<0.001) was more likely to be cancelled.

Conclusions: Close to half of EMS-activated stroke alerts were cancelled upon initial assessment. Only 5% of patients initially identified by EMS as having a potential acute stroke ultimately underwent EST. Better determination of LTKW and stroke symptoms would improve the accuracy of EMS-initiated stroke alerts.

Group cognitive-behavioral therapy for patients with epilepsy and comorbid depression and anxiety

Clinical Practice Guidelines for depression and anxiety recommend cognitive-behavioral therapy (CBT) as an equivalent and sometimes more effective treatment than medication. The limited research investigating CBT for anxiety and depression in epilepsy demonstrates mixed results. Described here is a pilot project using an existing group CBT intervention for symptoms of depression and/or anxiety, CBT Basics II, in patients with epilepsy. Eighteen patients with epilepsy, referred by neurologists to address depression and/or anxiety symptoms, completed the 10-week group. Results demonstrated improvements in depression, anxiety, negative automatic thoughts, and cognitive therapy knowledge and skills. The group was generally acceptable to patients as indicated by good attendance rates and only one dropout. This pilot project demonstrates that group CBT is a feasible, acceptable, and promising intervention for patients with epilepsy and comorbid depression and anxiety symptoms.

Intra-arterial administration of a replication-selective adenovirus (dl1520) in patients with colorectal carcinoma metastatic to the liver: a phase I trial

Both replication-incompetent and replication-selective adenoviruses are being developed for the treatment of cancer and other diseases. Concerns have been raised about the safety of intra-vascular adenovirus administration following a patient death on a clinical trial with a replication-defective adenovirus. In addition, the feasibility of vascular delivery to distant tumors has been questioned. dl1520 (ONYX-015) is a replication-selective adenovirus that has previously shown safety and antitumoral activity following intratumoral injection. This is the first report of intra-vascular administration with a genetically engineered, replication-selective virus. A phase I dose-escalation trial was performed in patients with liver-predominant gastrointestinal carcinoma (n = 11 total; primarily colorectal). dl1520 was infused into the hepatic artery at doses of 2 x 10(8)-2 x 10(1)2 particles for two cycles (days 1 and 8). Subsequent cycles of dl1520 were administered in combination with intravenous 5-fluorouracil (5-FU) and leucovorin. No dose-limiting toxicity, maximally tolerated dose or treatment-emergent clinical hepatotoxicity were identified following dl1520 infusion. Mild to moderate fever, rigors and fatigue were the most common adverse events. Antibody titers increased significantly in all patients. Viral replication was detectable in patients receiving the highest two doses. An objective response was demonstrated in combination with chemotherapy in a patient who was refractory to both 5-FU and dl1520 as single agents. Therefore, hepatic artery infusion of the attenuated adenovirus dl1520 was well-tolerated at doses resulting in infection, replication and chemotherapy-associated antitumoral activity.

Implantable spinal fusion stimulator: assessment of MR safety and artifacts

The objective of this investigation was to perform magnetic resonance (MR) imaging safety and artifact testing of an implantable spinal fusion stimulator. Magnetic field interactions, artifacts, and operational aspects of an implantable spinal fusion stimulator were evaluated in association with a 1.5 T MR system. Magnetic field-related translational attraction was measured using the deflection angle test. A special test apparatus was used to determine torque at 4.7 T. Artifacts were characterized using fast multiplanar spoiled gradient-echo, T1-weighted spin-echo, and T1-weighted fast spin-echo sequences. Operational aspects of the implantable spinal fusion stimulator before and after exposure to MR imaging at 1.5 T were assessed. In addition, nine patients (six lumbar spine and three cervical spine) with implantable spinal fusion stimulators underwent MR imaging. The findings indicated that magnetic field interactions were relatively minor, artifacts were well characterized and should not create diagnostic problems, and there were no changes in the operation of the spinal fusion stimulator. The nine patients underwent MR procedures without substantial adverse events or complaints. Based on the results of this investigation and in consideration of the findings from previous studies of MR imaging safety for the implantable spinal fusion stimulator, MR imaging may be performed safely in patients using MR systems operating at 1.5 T or less following specific recommendations and precautions.

Lack of correlation between HLA types and anti-idiotypic production in family members of a lupus patient

Correlations of anti-single-stranded (ss) DNA, anti-F(ab')2, and anti-idiotypes to HLA types of 16 healthy family members of a lupus patient were studied. High levels of anti-ss DNA (63%) and anti-F(ab')2 (69%) were detected. Of the 12 family members who expressed HLA-DR2 antigen, 8 had anti-ss DNA and anti-F(ab')2 antibodies. One out of 3 family members who shared the same HLA phenotypes, A1B8DR2, of the proband had high levels of anti-idiotype directed against the proband's F(ab')2 anti-DNA. Though a high prevalence of A1B8DR2, of anti-ss DNA, and of anti-F(ab')2 in healthy family members of a lupus patient was found, anti-idiotypes against anti-DNA were not dependent on HLA-A, B, Dr.

Antiidiotypic antibodies against anti-DNA antibodies in sera of families of lupus patients

We searched for antiidiotypes directed against anti-DNA in sera of healthy family members of lupus patients. Controls were healthy individuals without a personal or family history of lupus. No significant differences were noted between the family members' and the control group's sera with respect to binding to DNA or to non-anti-DNA F(ab')2 fragments. Family members' sera had higher binding to anti-DNA F(ab')2 and to normal IgG F(ab')2 fragments (P less than 0.01). Sera of the family members had significantly higher binding to anti-DNA F(ab')2 than to normal IgG F(ab')2 fragments (P less than 0.0036). Inhibition experiments have shown that the antiidiotype is directed against the framework determinants and not against the antigen binding sites of the idiotype. The antiidiotypic antibodies were directed against cross-reactive anti-DNA idiotypes and were not restricted to the idiotypes of the lupus proband. Age, sex, and blood relationship to the lupus patient did not influence the presence of antiidiotypes in the family members. The possible role of environmental factors in the induction of antiidiotypes and the role of the latter in regulating anti-DNA antibodies are discussed.

Efficacy of plain abdominal radiography in patients with gastrointestinal bleeding

To assess the value of plain abdominal radiography in cases of gastrointestinal hemorrhage, the records of 100 such consecutive patients were reviewed. Seventy-eight of the patients had presented to the emergency department, and 22 were inpatients. The radiologic and clinical records were scrutinized to determine the actual effect of the radiologic examination on management of the patient. Three patients had pneumoperitoneum attributed to bowel perforation, and two had confirmed bowel obstruction. In each, the clinical findings suggested the diagnosis. We found no instance of silent gastrointestinal bleeding in which plain radiography contributed important diagnostic information. We conclude that gastrointestinal bleeding is not, in itself, a valid indication for abdominal radiography.

Anti-idiotypic antibody against anti-DNA in sera of laboratory personnel exposed to lupus sera or nucleic acids

We tested for anti-DNA, anti-idiotypic, antinuclear, and lymphocytotoxic antibodies in the sera of three groups of normals: volunteers never exposed to lupus sera or nucleic acids (group I), research personnel handling nucleic acids (group II), and laboratory personnel handling lupus sera (group III). There was no significant differences among the groups with respect to levels of either single stranded or double stranded anti-DNA. Group I showed no significant differences in binding to F(ab')2 fragments of lupus anti-DNA, lupus non-anti-DNA or normal IgG. Compared to group I, groups II and III bound significantly higher to anti-DNA F(ab')2 fragments compared to non-anti-DNA F(ab')2 or normal F(ab')2 fragments. Sera from the three groups were negative for antibodies and all but one individual from group III had normal antinuclear antibody titres. These results indicate that sera of normals exposed to lupus sera or to nucleic acids contain an anti-idiotype directed against anti-DNA antibody. The possible role of these anti-idiotypes in regulating the anti-DNA antibody is discussed.

Study of anti-DNA antibodies prepared by DNA cellulose or Cibacron blue chromatography

We prepared anti-DNA antibodies from sera of lupus patients by either DNA cellulose or by Cibacron blue chromatography. Eluates from both columns were studied with respect to recovery of IgG, recovery, purification and specificity of anti-DNA activity. An attempt was made to raise rabbit anti-idiotypic antibodies against both eluates. DNA cellulose chromatography--if DNA leakage was prevented--yielded 58% recovery and 58-fold purification of the anti-DNA activity present in the original purified IgG sample. 1% of loaded IgG was recovered. Cibacron blue chromatography yielded 32% recovery and 1.1-fold purification of the anti-DNA activity. 29% of loaded IgG was recovered. Eluates of Cibacron blue were not pure as shown by their high binding activity against an unrelated antigen, tetanus toxoid. Eluates from DNA cellulose were pure and did not show anti-tetanus toxoid activity. Rabbit anti-idiotypic antibodies could be raised only against eluates of DNA cellulose suggesting that the eluates of Cibacron blue did not contain enough idiotypes to induce anti-idiotypic antibodies. The characterization of the rabbit anti-idiotypic antibodies showed that it contained two populations, one against site-specific idiotypes and the other against framework idiotypes. Anti-DNA antibodies prepared by Cibacron blue had idiotypes similar to those prepared by DNA cellulose. The present study demonstrates that DNA cellulose chromatography--if leakage of DNA is prevented--can yield excellent recovery and purification of anti-DNA activity. Anti-DNA antibodies prepared by DNA cellulose were enriched and could induce anti-idiotypic antibodies in rabbits. Tube chromatography on Cibacron blue yielded poor recovery and minimal enrichment of anti-DNA activity.

Renal vascular and tubular effects of vanadate in the anesthetized rat

The purpose of these experiments was to establish the renal vascular and tubular effects of vanadate. Three groups of adult rats were anesthetized with Na pentobarbital and given an i.v. infusion of a physiological saline solution at 0.055 ml/min. After a 60-min equilibration period, mean arterial blood pressure was measured, as were clearances of para-amino-hippuric acid (CPAH) and inulin (Cin), urine flow (V) and osmolality (Uosm) and the excretion rates of Na (UNaV), of K (UKV) and of Ca (UCaV). After the initial measurements, the i.v. infusion of physiological saline was continued in group 1 (controls), while vanadate was added to the saline and infused at 0.07 and 0.14 microM/min in groups 2 and 3. Then, all measurements were repeated. Compared with the control group, the following dose-dependent changes were observed in the vanadate-infused rats: increased mean arterial blood pressure, decreased CPAH (effective renal plasma flow), decreased Cin (glomerular filtration rate), increased V, UNaV and UCaV and decreased Uosm and UKV. Both the renal vascular and renal tubular effects of vanadate are similar to the renal effects of ouabain, previously reported by others. These effects can be explained by inhibitory effects of vanadate on Na,K-adenosine triphosphatase (ATPase) and/or Ca/ATPase activities of renal vascular and tubular cells.

Cell cycle progression of murine sarcoma cells after x irradiation or heat shock

DNA histograms of exponentially growing EMT-6 cells in vitro were obtained at regular time intervals after exposure at 300 rads of x rays or one hour of heat shock at 43 degrees C. After either treatment, about 70% of the cells retained clonogenicity. Irradiation induced the expected block in the G2 + M phase, resulting in an increase of cells in that phase during the first 5 hours after exposure. Heat shock caused a block in both the S and G2 +M phases.