Cognitive Digital Biomarkers from Automated Transcription of Spoken Language

BACKGROUND

Although patients with Alzheimer's disease and other cognitive-related neurodegenerative disorders may benefit from early detection, development of a reliable diagnostic test has remained elusive. The penetration of digital voice-recording technologies and multiple cognitive processes deployed when constructing spoken responses might offer an opportunity to predict cognitive status.

OBJECTIVE

To determine whether cognitive status might be predicted from voice recordings of neuropsychological testing.

DESIGN

Comparison of acoustic and (para)linguistic variables from low-quality automated transcriptions of neuropsychological testing (n = 200) versus variables from high-quality manual transcriptions (n = 127). We trained a logistic regression classifier to predict cognitive status, which was tested against actual diagnoses.

SETTING

Observational cohort study.

PARTICIPANTS

146 participants in the Framingham Heart Study.

MEASUREMENTS

Acoustic and either paralinguistic variables (e.g., speaking time) from automated transcriptions or linguistic variables (e.g., phrase complexity) from manual transcriptions.

RESULTS

Models based on demographic features alone were not robust (area under the receiver-operator characteristic curve [AUROC] 0.60). Addition of clinical and standard acoustic features boosted the AUROC to 0.81. Additional inclusion of transcription-related features yielded an AUROC of 0.90.

CONCLUSIONS

The use of voice-based digital biomarkers derived from automated processing methods, combined with standard patient screening, might constitute a scalable way to enable early detection of dementia.

Immune Marker Profiling and Programmed Death Ligand 1 Expression Across NSCLC Mutations

INTRODUCTION

Programmed death 1/programmed death ligand 1 (PD-L1) axis inhibitors have been proven effective, especially in patients with tumors expressing PD-L1. Their clinical efficacy in patients with EGFR-activating mutations is still unclear, whereas KRAS mutations seem to be associated with good response.

METHODS

We used multiplexed quantitative immunofluorescence to investigate PD-L1 expression and to characterize tumor infiltrating lymphocyte (TIL) populations and their activation status in more than 150 NSCLC patients with known mutation status.

RESULTS

PD-L1 expression was significantly lower in EGFR-mutant compared to KRAS-mutant, and EGFR/KRAS wild-type (WT) tumors. KRAS mutant tumors were more inflamed with higher CD4+, CD8+ and CD20+ TILs. Subgroup analysis by TIL activation status revealed that EGFR mutants had a high frequency of inactive TILs even though lymphocytes were present in the tumor microenvironment. In contrast, in KRAS mutants, when TILs were present they were almost always active. Additionally, we found differences between EGFR mutation sites in CD8+ expression and the TIL activation profile. Finally, activated EGFR correlated with increased PD-L1 expression in EGFR mutants but not in EGFR WT, whereas TIL activation was associated with higher PD-L1 only in EGFR/KRAS WT.

CONCLUSIONS

Our findings show the unique immune profile of EGFR-mutant tumors. The high frequency of inactive TILs could explain the low immunotherapy response rates in these patients, whereas PD-L1 as a predictive biomarker may reflect the constitutive oncogenic signaling rather than immune signaling, which would be associated with high PD-L1 levels and TILs activation.

Tumor-Infiltrating Lymphocytes and PD-L1 Expression in Pre- and Posttreatment Breast Cancers in the SWOG S0800 Phase II Neoadjuvant Chemotherapy Trial

Our aim was to examine the association of pretreatment tumor-infiltrating lymphocyte (TIL) count and PD-L1 levels with pathologic complete response (pCR) and assess immune marker changes following treatment in tumor specimens from the S0800 clinical trial, which randomized patients to bevacizumab + nab-paclitaxel, followed by doxorubicin/cyclophosphamide (AC) versus two control arms without bevacizumab (varying sequence of AC and nab-paclitaxel). TILs were assessed in 124 pre- and 62 posttreatment tissues (including 59 pairs). PD-L1 was assessed in 120 pre- and 43 posttreatment tissues (including 39 pairs) using the 22C3 antibody. Baseline and treatment-induced immune changes were correlated with pCR and survival using estrogen receptor (ER) and treatment-adjusted logistic and Cox regressions, respectively. At baseline, the mean TIL count was 17.4% (17% had zero TILs, 9% had ≥50% TILs). Posttreatment, mean TIL count decreased to 11% (5% had no TILs, 2% had >50% TILs). In paired samples, the mean TIL change was 15% decrease. Baseline PD-L1 was detected in 43% of cases (n = 5 in tumor cells, n = 29 stroma, n = 18 tumor + stroma). Posttreatment, PD-L1 expression was not significantly lower (33%). Higher baseline TIL count and PD-L1 positivity rate were associated with higher pCR rate even after adjustment for treatment and ER status (P = 0.018). There was no association between TIL counts, PD-L1 expression, and survival due to few events. In conclusion, TIL counts, but not PD-L1 expression, decreased significantly after treatment. Continued PD-L1 expression in some residual cancers raises the possibility that adjuvant immune checkpoint inhibitor therapy could improve survival in this patient population. Mol Cancer Ther; 17(6); 1324-31. ©2018 AACR.

Immune marker profiling and PD-L1, PD-L2 expression mechanisms across non-small cell lung cancer mutations

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Background: PD-1/PD-L1 axis inhibitors have been proven effective, especially in patients expressing Programmed Death Ligand 1 (PD-L1). Their clinical efficacy in patients with epidermal growth factor receptor (EGFR) activating mutations is still unclear, while KRAS mutations seem to be associated with high response rates. In this study we investigated the expression of PD-L1, PD-L2 and Tumor Infiltrating Lymphocyte (TIL) status as a function of mutation status in Non-Small Cell Lung Cancer (NSCLC). Methods: We used the AQUA method of quantitative fluorescence (QIF) to compare PD-L1 and PD-L2 expression and to characterize TILs populations and their activation status in over 150 NSCLC patient tumors with known mutation status. EGFR activation was assessed in situ using the proximity ligation assay (PLA) for EGFR and GRB2 and T cell activation was assessed using a novel multiplexed QIF assay including CD3, Granzyme B and Ki67. Results: PD-L1 tumor and stroma expression was significantly lower in EGFR mutant compared to KRAS mutant (p = 0.009) and EGFR/KRAS Wild Type (p < 0.0001) tumors, while they had a higher frequency of PD-L2 expression. Conversely, KRAS mutants had significantly lower PD-L2 tumor and stroma expression but they were also more inflamed with higher CD4+, CD8+ and CD20+ TILs. Subgroup analysis of patients by their TILs activation status revealed that EGFR mutants had a very high frequency of inactive TILs even though lymphocytes were present in the tumor microenvironment. In contrast, in KRAS mutants, when TILs were present, they were almost always active. Finally, we find that PLA-defined activated EGFR correlated with increased PD-L1 expression in EGFR mutants but not in EGFR WT, while TIL activation was associated with higher PD-L1 in EGFR/KRAS WT. Conclusions: Our findings are consistent with the unique biology of EGFR mutant tumors. The high frequency of inactive TILs could explain the low immune therapy response rates in this patient group. Similarly, in this group, the reason PD-L1 expression fails to predict response may be due to expression as a result of constitutive oncogenic signaling rather than immune signaling, which would be associated with high PD-L1 levels and TILs activation.

Effects of neoadjuvant chemotherapy (NAC) on tumor infiltrating lymphocytes (TIL) and PD-L1 expression in the SWOG S0800 clinical trial

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Background: Higher baseline TILs and PD-L1 expression are associated with greater pathologic complete response (pCR) rates, but how chemotherapy affects these immune parameters is unknown. The goal of this study was to examine TIL and PD-L1 expression in pre- and post-NAC tumor specimens from the S0800 clinical trial that compared weekly nab-paclitaxel/bevacizumab + dose-dense doxorubicin and cyclophosphamide (AC) with nab-paclitaxel + AC as NAC for HER2-negative cases. Association between immune parameters, pCR and NAC-induced changes were tested using ER and NAC-arm adjusted logistic regression. Methods: TILs were assessed on H&E stained full sections of 120 pre- and 62 post-NAC tissues (tumor bed of pCR) including 59 matched samples. PD-L1 immunohistochemistry was performed using the FDA cleared 22C3 assay and results were available for 121 baseline and 43 matched post-NAC samples. Results: At baseline, the mean TIL count was 18%; 16% had no TILs and 9% had > 50% TILs. Higher baseline TILs were associated with higher pCR rate (p = 0.043, trend test p = 0.014) but there was no interaction with NAC arm. Post-NAC, the mean TIL counts was 11%; 5% had no TILs and 1.6% had > 50% TILs. In the matching post-NAC samples, the mean change was 15% decrease in TILs, but in 32% of cases TILs increased. Cases with residual disease (n=44) had lesser average decrease (p=0.029) than cases with pCR (n=15). The post-NAC decrease in TILs was also observed after excluding cases with pCR. At baseline, PD-L1 expression either in the stroma or on epithelial cells or in both was detected in 52 (43%) of 121 cases (5 tumor only, 29 stroma only, 18 tumor + stroma). Those with baseline PD-L1 expression had higher pCR (63% vs. 37%; p=0.008). Post-NAC, PD-L1 expression was seen in 14 of 43 (33%) cases (7 stroma only, 7 tumor + stroma). In the 39 matching pre- and post-NAC samples, PD-L1 expression was negative in both in 20, positive in both in 10 cases and 6 patients had PD-L1 expression at baseline but not in the post-NAC sample. Conclusions: TIL counts and PD-L1 expression generallydecreased, but in a minority of cases increased after NAC. The decrease in TIL was significantly greater in cases achieving pCR. Clinical trial information: NCT00856492.

Abstract P1-03-07: High concordance of a closed system, near point of care, RT-qPCR breast cancer assay for HER2 (ERBB2) mRNA compared to both IHC/FISH and quantitative immunofluorescence

Background

Reliable assessment of HER2 receptor status in breast cancer by either IHC or FISH does not unequivocally define receptor expression, due to their semi-quantitative nature, and as many as 10-15% of cases fall into the ASCO/CAP “equivocal” category. Historically, RNA measurements by PCR, including using several commercially available platforms, have been tested, but have not gained broad acceptance for assessment of HER2. However, RNA measurement, as a continuous value, has potential for use for adjudication of the equivocal category. In the current study, we used a real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) assay (GeneXpert® Breast Cancer Stratifier RUO Assay, Cepheid, Sunnyvale, CA, USA) for ERBB2 (HER2) mRNA on the GeneXpert® (GX) platform (Cepheid), which utilizes a closed-system, single-use cartridge, automated system. The RT-qPCR results from GX were then compared with results from clinical HER2 IHC/FISH assays following ASCO/CAP 2013 HER2 testing guidelines (Wolff et al JCO 2013) and quantitative immunofluorescence (QIF).

Methods

Multiple cores (1mm in diameter) were retrospectively collected from 80 formalin-fixed paraffin-embedded (FFPE) tissue blocks with invasive breast cancer seen by Yale Pathology Labs between 1998 and 2011. Tissue cores were processed as lysates for testing at Yale in the automated GX assay. Briefly, gene-specific reverse transcription was performed, followed by RT-qPCR (TaqMan) and ERBB2 mRNA results were expressed as the difference in cycle threshold values (delta Ct) between the endogenous control transcript (CYFIP1) and the ERBB2 mRNA transcript. Results from IHC and FISH were extracted from the pathology reports for the Yale CLIA lab and QIF for each case was measured as previously described (Carvajal et al, JNCI 2015).

Results

Quality control testing showed that the GX platform shows no case to case cross contamination on material from routine histology practices. Concordance between RT-qPCR and IHC/FISH was 91.25% (sensitivity = 0.87; specificity = 0.94; PPV = 0.89; NPV = 0.92) using a pre-defined delta Ct cut-off (dCt ≥ -1) for HER2 (+) based on prior concordance studies with HER2 IHC/FISH. Concordance between RT-qPCR and QIF was 99% (sensitivity = 0.97; specificity = 1.0; PPV = 1.0; NPV = 0.98) using dCt ≥ -1 and the pre-defined cut-point for positivity by QIF.

Conclusions

The GX closed system RT-qPCR assay shows greater than 90% concordance with the ASCO/CAP 2013 HER2 IHC/FISH scoring. Additionally, the GX RT-qPCR assay is highly concordant (99%) with the continuous variable HER2 QIF assay, and may better reflect the true continuum of HER2 receptor status in invasive breast cancer. These initial results suggest that rapid, closed system molecular assays may have future value for the adjudication of the ASCO/CAP HER2 equivocal category. This pilot study did not include ASCO/CAP 2013 “equivocal” cases, but that effort is underway.

Citation Format: Wasserman B, Carvajal-Hausdorf D, Ho K, Wong W, Wu N, Chu VC, Lai EW, Weidler JM, Bates M, Neumenister V, Rimm DL. High concordance of a closed system, near point of care, RT-qPCR breast cancer assay for HER2 (ERBB2) mRNA compared to both IHC/FISH and quantitative immunofluorescence [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-03-07.

Feasibility of postmortem device acquisition for potential reuse in underserved nations

OBJECTIVES

The purpose of the present study was to examine the feasibility and efficacy of a program to acquire devices with adequate battery life from crematories and funeral homes for potential reutilization in underserved nations.

BACKGROUND

There exists a great health-care disparity between the industrialized world and underserved nations--specifically in the frequency of pacemaker implantation.

METHODS

Flyers were mailed to all 1057 members of the Michigan Funeral Directors Association providing information to download a consent-for-explant form and request a postage-paid envelope from www.myheartyourheart.org in order to send explanted devices. Donated devices from funeral homes and crematories nationwide were also collected from World Medical Relief. Adequate battery life was defined as ≥75% or ≥4 years of estimated longevity.

RESULTS

A total of 3176 devices (65% pacemakers, 21% implantable cardioverter-defibrillators [ICDs], 12% biventricular ICDs, and 3% biventricular pacemakers) were donated to the reutilization program. Five hundred fifty devices (21%; 95% confidence interval [CI] 19.4-22.6%) were found to have an acceptable battery life for reutilization. Among these devices, 313 were pacemakers (17.9%; 95% CI 16.1-19.8%), 118 were ICDs (17.9%; 95% CI 15.1-21.1%), 112 were biventricular ICDs (30.3%; 95% CI 25.6-35.2%), and 7 were biventricular pacemakers (17.3%; 95% CI 16.0-18.7%).

CONCLUSIONS

Approximately 21% of donated devices and 30% of donated biventricular ICDs possess an adequate battery life for potential reuse. Device donations from funeral homes and crematories appear to be a potential resource for device reutilization for those in need in underserved nations.

Association of blood monocyte and platelet markers with carotid artery characteristics: the atherosclerosis risk in communities carotid MRI study

BACKGROUND

Atherosclerosis is characterized by infiltration of inflammatory cells from circulating blood. Blood cell activation could play an important role in plaque formation.

METHODS

We analyzed the relationship between blood cellular markers and quantitative measures of carotid wall components in 1,546 participants from the ARIC (Atherosclerosis Risk in Communities) Carotid MRI Study. Carotid imaging was performed using a gadolinium contrast-enhanced MRI and cellular phenotyping by flow cytometry.

RESULTS

Monocyte Toll-like receptor (TLR)-2 is associated with larger plaques, while CD14, myeloperoxidase, and TLR-4 associate with smaller. Platelet CD40L is associated with smaller plaques and thinner caps, while P-selectin is associated with smaller core size.

CONCLUSIONS

Blood cell activation is significantly associated with atherosclerotic changes of the carotid wall.

Implantation-Induced Conductivity of Polymers

Ion implantation causes an increase by ~14 orders of magnitude in the electricalconductivity of normally insulating polymers such as polyacrylonitrile (PAN), poly(2,6 dimethyl phenylene-oxide) (PPO), and poly (pphenylene sulfide) (PPS), after ion implantation with Br at fluences of 3 × 1015 ions/cm2. The temperature dependence of the dc conductivity was measured in the range 23 〈 T 〈 293 K and results show an exponential law σ ~ exp(−To/T)a) for PAN, PPO and PPS with α =1/2, suggesting a one-dimensional hopping mechanism. The temperature dependence of the thermoelectric power (TEP) identifies the sign of the dominant carrier type. The TEP exhibits linear metallic behavior, with small magnitudes (~3μV/K), and shows Br implantation to yield p-type material in PPS and n-type material in PAN with extremely low values of mobility (〈 10−3 cm2/V sec) and correspondingly very high values of the carrier concentration estimated to be 5 × 1022 cm-3. Results are also reported for the frequency dependence of the AC conductivity and of similarly implanted PPS and PAN samples.

Ion Implantation of Polymers

Ion implantation provides a mechanism for radically modifying the electronic and transport properties of a variety of polymers that are normally insulating. By using masks and tailoring the implanted species and ion energies, conducting paths in an insulating medium can be fabricated between specific reference points, an application of obvious relevance to the microelectronics industry. Specific results are reported for modification of the structure, electrical conductivity, thermoelectric-power, optical transmission and electron spin resonance for several polymers under a variety of implantation conditions. The temperature and frequency dependence of the conductivity suggest a onedimensional variable range hopping mechanism for conduction along the polymer chains. Comparison is made between implantation in the 200 keV and 2 MeV energy ranges.

Prepubertal distal longitudinal vaginal folds

OBJECTIVE

The purpose of this paper is to further describe prepubertal distal longitudinal vaginal folds and its natural history.

DESIGN

Biopsy of the folds and follow-up through puberty.

RESULTS

Histology of the folds shows normal vaginal mucosa over loose fibrous connective tissue without a firm fibrous core. The folds disappear in puberty.

CONCLUSIONS

Prepubertal distal longitudinal folds are common, and disappear probably by spreading out during puberty with the physiologic estrogenic widening and lengthening of the vagina. This can occur because the folds do not have a dense fibrous core. The folds may be confused with the vaginal rhabdomyosarcoma or sexual molestation if the fold reaches the hymen, and forms a "bump". The folds are benign.

Allergic rhinitis and wellness opportunities

Allergic rhinitis affects one in 10 adult workers and results in substantial costs to employers in terms of health care and reduced worker productivity. In this article, the author describes many employer-based initiatives, which complement professional interventions.

Linkage of a locus for autosomal dominant familial spastic paraplegia to chromosome 2p markers

'Pure' autosomal dominant familial spastic paraplegia (SPG) is a neurodegenerative disease which clinically manifests as spasticity of the lower limbs. Dominantly inherited SPG is known to be clinically heterogenous and has been classified into late-onset and early-onset types, based on the age of onset of symptoms. We tested five autosomal dominant SPG families for genetic linkage and established linkage to chromogene 2p markers (Z(theta) = 3.65) with evidence of genetic locus heterogeneity. Three late-onset SPG families and one early-onset SPG family had high posterior probability of linkage (P > 0.94) to chromosome 2p, while the fifth family (a very early-onset family) was not linked to chromosome 2 and showed high probability of linkage to chromosome 14q. These data provide a basis for a classification of SPG according to chromosome location rather than age of onset of symptoms.

Use of Vicryl (polyglactin-910) mesh implant for repair of orbital floor fracture causing diplopia: a study of 28 patients over 5 years

Over the past 5 years, Vicryl mesh (polyglactin-910) implants were used successfully to reconstruct the orbital floor in 28 patients with significant preoperative diplopia due to orbital floor fractures. The layered mesh is available in 26.5 x 24 cm sheets, each of which is folded onto itself into 24 layers and packaged; 24 layers are approximately 4 mm thick. Appropriately sized implants varying in thickness from 6 to 56 layers were used to cover and fill the orbital floor defect. Absorbable Vicryl mesh is well-tolerated by orbital tissues; since it is soft and pliable, it is unlikely to compress orbital structures such as the optic nerve, lacrimal sac, or extraocular muscles. A second surgical site necessary for autogenous implants is avoided. The Vicryl mesh implant is technically easy to insert and does not require fixation in the orbit. Because Vicryl mesh is absorbable, the risks associated with permanent alloplastic implants are reduced. Similarly, there is no potential spread of communicable disease with homologous tissue implants. Follow-up ranged from 1 month to 2 years (median, 13 months). None of the patients had late complications. The only complication was transient, low-grade eyelid inflammation in four patients.

Intrinsic and extrinsic carpal ligaments: evaluation by three-dimensional Fourier transform MR imaging

OBJECTIVE

As evaluation of the anatomic and functional integrity of intrinsic and extrinsic carpal ligaments with conventional imaging methods is difficult, we designed a study to evaluate the ability of three-dimensional Fourier transform MR imaging to show the carpal ligaments.

SUBJECTS AND METHODS

We obtained coronal MR images of 15 cadaveric wrists and 15 wrists of patients, using three-dimensional volume acquisition with a gradient-recalled echo sequence and a 1.5-T magnet. The MR findings were compared with the findings on dissection in the 15 cadaveric wrists and with the surgical findings in eight patients.

RESULTS

All the volar ligaments had a striated appearance on MR images, with alternating bands of low and intermediate signal intensity. No tears of the extrinsic ligaments were seen. The intrinsic scapholunate and lunotriquetral ligaments were seen as structures with more homogeneously intermediate intensity attaching to their adjacent bone through high-signal-intensity hyaline cartilage. For the cadaveric wrists, MR indications of a tear of the scapholunate ligament were true-positive in three and false-negative in three; indications of a tear of the lunotriquetral ligament were true-positive in five, false-positive in two, and false-negative in one. For the eight patients with surgical confirmation, the MR findings regarding tears were true-positive in two and true-negative in six. Neither surgery nor MR imaging showed any tears of the scapholunate ligament.

CONCLUSION

Three-dimensional Fourier transform MR imaging with thin slices provides the resolution necessary to visualize the anatomic detail of the extrinsic and intrinsic ligaments of the wrist, but additional clinical experience with this technique will be required to determine its diagnostic capabilities.

The relationship of initial clinical parameters to the long-term response in 112 cases of periodontal disease

The purpose of the present study was to determine whether any of the clinical parameters recorded during an initial periodontal examination would relate to the course of periodontal cases maintained for long periods of time. Based on available documentation, cases which had a downhill course were assembled from a population previously studied. In addition, long-term cases currently under maintenance care were drawn from our private practice. On average, the patients had been under care for 23 years. The study population was heavily weighted toward downhill cases to better compare these cases with those usually found in periodontal practice. Positive statistical correlations were found between the amount of subgingival calculus and the degree of gingival inflammation at initial examination. Disease severity initially was positively correlated to long-term course of disease. The amount of subgingival calculus did not relate to the long-term result. There was a strong correlation between inflammatory gingival hyperplasia initially and good long-term maintenance. The results suggest that, in combination, initial characteristics of periodontal cases coupled with long-term results of treatment may aid in further subclassifying the periodontal diseases.

Fast and efficient purification of yeast plasma membranes using cationic silica microbeads

A fast and efficient procedure for the purification of plasma membranes of Saccharomyces cerevisiae is described. Protoplasts served as starting material. They were coated with cationic silica microbeads. After lysis, the plasma membranes were washed free from debris and cell organelles. This procedure resulted in a high yield (about 85%) of plasma membranes, as judged by measuring vanadate-sensitive ATPase as a plasma membrane marker. The enzyme was enriched 12-fold relative to the homogenate after lysis. Its specific activity was 1.5--2.0 micromol/min per mg protein, the pH optimum was 6.5, and 10 microM vanadate was sufficient to obtain maximum inhibition. Based on the assay of internal markers and electron microscopic studies, we found our preparation essentially free of contamination from other cell organelles.

Prevention of acute paraquat toxicity in rats by superoxide dismutase

Paraquat is a widely used herbicide which causes lung injury in man characterized by progressive parenchymal damage that may lead to fatal respiratory failure. The precise mechanism of injury is unknown but is related to the cyclic oxidation and reduction of paraquat in cells with resultant production of free radicals of oxygen. In this study, superoxide dismutase (SOD), an enzyme that catalyzes the dismutations of superoxide free radical (O2-) to less toxic forms, plus reduced glutathione (GSH), and d-propranolol (PROP), were evaluated for their ability to protect against acute paraquat toxicity. Rats maintained at room air were given 50 mg paraquat dichloride/kg body weight in a single intraperitoneal (IP) injection 60 min prior to receiving either 0.2, 2, 10, or 20 mg/kg/d SOD, 3.6, 7.2, or 14.4 mmol/kg/d GSH, 2 or 20 mg/kg/d PROP, or an equal volume of normal saline (controls) LP. in divided doses for 3 d. SOD significantly prolonged and increased survival at doses of 2, 10, or 20 mg/kg/d (p less than 0.05). In addition, histologic lung morphology in SOD-treated rats showed only minimal intra-alveolar hemorrhage and hypercellularity 24, 48, and 168 h after paraquat challenge. Treatment with GSH, PROP or 0.2 mg/kg/d SOD was not protective. Duration of survival, percent survival, and lung morphology in these groups were not significantly different from controls. These results indicate that a) SOD protects against the development of acute paraquat toxicity in rats, b) one mechanism of paraquat poisoning is increased biologic production of O2-, and c) SOD may have a role in the therapy of paraquat poisoning in man.

A long-term survey of tooth loss in 600 treated periodontal patients

1. Six hundred patients in a private periodontal practice were reexamined an average of 22 years after their active treatment and the patterns of tooth loss were observed. 2. During the post-treatment period, 300 patients had lost no teeth from periodontal disease, 199 had lost one to three teeth, 76 had lost 4 to 9 teeth and 25 had lost 10 to 23 teeth. 3. Of 2,139 teeth that originally had been considered of questionable prognosis, 666 were lost. Of these, 394 were lost by one sixth of the patients and only 272 by the other five-sixths. 4. Of 1,464 teeth which originally had furcation involvements, 460 were lost, 240 of them by one-sixth of the patients who deteriorated most. 5. The mortality of teeth which were treated with periodontal surgery was compared with that of teeth which did not have surgery. Tooth retention seemed more closely related to the case type than the surgery performed. 6. In general, periodontal disease is bilaterally symmetrical and there is a predictable order of likelihood of tooth loss according to position in the arch.