Provider- and Facility-Level Variation in Precancerous Cervical Biopsy Diagnoses

OBJECTIVES

Reproducibility of cervical biopsy diagnoses is low and may vary based on where the diagnostic test is performed and by whom. Our objective was to measure multilevel variation in diagnoses across colposcopists, pathologists, and laboratory facilities.

METHODS

We cross-sectionally examined variation in cervical biopsy diagnoses within the 5 sites of the Population-Based Research Optimizing Screening through Personalized Regimens (PROSPR I) consortium within levels defined by colposcopists, pathologists, and laboratory facilities. Patients aged 18 to 65 years with a colposcopy with biopsy performed were included, with diagnoses categorized as normal, cervical intraepithelial neoplasia grade 1 (CIN1), grade 2 (CIN2), and grade 3 (CIN3). Using Markov Chain Monte-Carlo methods, we fit mixed-effects logistic regression models for biopsy diagnoses and presented median odds ratios (MORs), which reflect the variability within each level. Median odds ratios can be interpreted as the average increased odds a patient would have for a given outcome (e.g., CIN2 or CIN3 vs normal or CIN1) when switching to a provider with higher odds of diagnosing that outcome. The MOR is always 1 or greater, and a value of 1 indicates no variation in outcome for that level, with higher values indicating greater variation.

RESULTS

A total of 130,110 patients were included who received care across 82 laboratory facilities, 2,620 colposcopists, and 489 pathologists. Substantial variation in biopsy diagnoses was found at each level, with the most occurring between laboratory facilities, followed by pathologists and colposcopists. Substantial variation in biopsy diagnoses of CIN2 or CIN3 (vs normal or CIN1) was present between laboratory facilities (MOR: 1.26; 95% credible interval = 1.19-1.36).

CONCLUSIONS

Improving consistency in cervical biopsy diagnoses is needed to reduce underdiagnosis, overdiagnosis, and unnecessary treatment resulting from variation in cervical biopsy diagnoses.

Cytologic processing of ureteral microbiopsies is associated with higher sensitivity for detection of urothelial carcinoma compared with conventional biopsy processing

INTRODUCTION

Because of the high rates of false-negative or nondiagnostic ureteral Piranha microbiopsies associated with low cellularity, we assessed the effect of processing these using cytology.

MATERIALS AND METHODS

We included 2 groups of 44 consecutive microbiopsies processed from formalin as a standard surgical biopsy and 22 processed by cytology. All samples were from the ureter or renal pelvis or calyx. The cytology samples were collected in alcohol-based media and were prepared with a Cellient cell block only (n = 9) or with a Cellient cell block for the visible particles, together with ThinPrep, to capture the remaining desquamated cells (n = 13).

RESULTS

Malignancy was diagnosed in 5 of 44 conventionally processed microbiopsies (11%) compared with 14 of 22 cytologically processed microbiopsies (64%; P < 0.001), including 1 case with invasion. Nineteen site-matched biopsies from 2 patients had undergone both cytologic and surgical processing, with 8 of 8 cytologically processed biopsies diagnosed as malignant. None of the 11 surgically processed biopsies from the same patients matched for site were diagnosed as malignant. Of the 11, 2 (18%) were suspicious for high-grade urothelial carcinoma and 6 (55%) were considered atypical. Increased sensitivity from cytologic processing appears related to increased cell recovery; large numbers of well-preserved urothelial cells were identified in the ThinPrep (range, 1000-25,000 cells/slide), and a nonsignificant trend was found toward increased urothelium (defined as >200 cells/profile) in the Cellient cell blocks (14 of 22 [64%]) compared with the histologic biopsies (17 of 44 [39%]; P = 0.070).

CONCLUSIONS

Cytologic processing of ureteral microbiopsies showed superior sensitivity for detecting high-grade urothelial carcinoma, apparently owing to the increased cellular recovery.

High-density linkage maps and loci for berry color and flower sex in muscadine grape (Vitis rotundifolia)

Linkage maps of muscadine grape generated using genotyping-by-sequencing (GBS) provide insight into genome collinearity between Muscadinia and Euvitis subgenera and genetic control of flower sex and berry color. The muscadine grape, Vitis rotundifolia, is a specialty crop native to the southeastern USA. Muscadine vines can be male, female, or perfect-flowered, and berry color ranges from bronze to black. Genetic linkage maps were constructed using genotyping-by-sequencing in two F₁ populations segregating for flower sex and berry color. The linkage maps consisted of 1244 and 2069 markers assigned to 20 linkage groups (LG) for the 'Black Beauty' × 'Nesbitt' and 'Supreme' × 'Nesbitt' populations, respectively. Data from both populations were used to generate a consensus map with 2346 markers across 20 LGs. A high degree of collinearity was observed between the genetic maps and the Vitis vinifera physical map. The higher chromosome number in muscadine (2n = 40) compared to V. vinifera (2n = 38) was accounted for by the behavior of V. vinifera chromosome 7 as two independently segregating LGs in muscadine. The muscadine sex locus mapped to an interval that aligned to 4.64-5.09 Mb on V. vinifera chromosome 2, a region which includes the previously described V. vinifera subsp. sylvestris sex locus. While the MYB transcription factor genes controlling fruit color in V. vinifera are located on chromosome 2, the muscadine berry color locus mapped to an interval aligning to 11.09-11.88 Mb on V. vinifera chromosome 4, suggesting that a mutation in a different gene in the anthocyanin biosynthesis pathway determines berry color in muscadine. These linkage maps lay the groundwork for marker-assisted breeding in muscadine and provide insight into the evolution of Vitis species.

Zeta potentials of the rare earth element fluorcarbonate minerals focusing on bastnäsite and parisite

Rare earth elements (REE) are critical to a wide range of technologies ranging from mobile phones to wind turbines. Processing and extraction of REE minerals from ore bodies is, however, both challenging and relatively poorly understood, as the majority of deposits contain only limited enrichment of REEs. An improved understanding of the surface properties of the minerals is important in informing and optimising their processing, in particular for separation by froth flotation. The measurement of zeta potential can be used to extract information regarding the electrical double layer, and hence surface properties of these minerals. There are over 34 REE fluorcarbonate minerals currently identified, however bastnäsite, synchysite and parisite are of most economic importance. Bastnäsite-(Ce), the most common REE fluorcarbonate, supplies over 50% of the world's REE. Previous studies of bastnäsite have showed a wide range of surface behaviour, with the iso-electric point (IEP), being measured between pH values of 4.6 and 9.3. In contrast, no values of IEP have been reported for parisite or synchysite. In this work, we review previous studies of the zeta potentials of bastnäsite to investigate the effects of different methodologies and sample preparation. In addition, measurements of zeta potentials of parisite under water, collector and supernatant conditions were conducted, the first to be reported. These results showed an iso-electric point for parisite of 5.6 under water, with a shift to a more negative zeta potential with both collector (hydroxamic and fatty acids) and supernatant conditions. The IEP with collectors and supernatant was <3.5. As zeta potential measurements in the presence of reagents and supernatants are the most rigorous way of determining the efficiency of a flotation reagent, the agreement between parisite zeta potentials obtained here and previous work on bastnäsite suggests that parisite may be processed using similar reagent schemes to bastnäsite. This is important for future processing of REE deposits, comprising of more complex REE mineralogy.

Mass Forming Eosinophilic Cystitis in Pediatric Patients

Eosinophilic cystitis (EC) is an uncommon inflammatory disorder of uncertain etiology that has been described in adult and pediatric populations. We describe 3 recent cases of EC that presented as a mass lesion in pediatric patients from the New England region of the United States. All patients were initially suspected to have a malignancy, and biopsy was performed, which ultimately led to the diagnosis of EC. We propose the use of eosinophil density of >25 eosinophils per high-power field and myocyte degeneration as supportive histopathologic features to make this diagnosis. It is of utmost importance to consider EC in the differential diagnosis when approaching a pediatric patient with a bladder mass.

Absence or Presence of High-Grade Squamous Intraepithelial Lesion in Cervical Conization Specimens: A Clinicopathologic Study of 540 Cases

OBJECTIVES

To explore the implications of cervical conization specimens lacking the targeted high-grade squamous intraepithelial lesions (negative cone).

METHODS

We studied 540 conization procedures: 400 positive cones and 140 negative cones. Clinicopathologic features and 2-year follow-up results were reported.

RESULTS

Negative cones comprised 22% of procedures triggered by CIN2 or higher biopsies. Procedures triggered by cytology produced much higher percentages of negative cones (37% high-grade squamous intraepithelial lesion [HSIL], 46% atypical squamous cells-cannot exclude high-grade squamous intraepithelial lesion [ASC-H], and 76% low-grade squamous intraepithelial lesion-cannot exclude high-grade squamous intraepithelial lesion [LSIL-H]). Upon reviewing negative excision-triggering biopsy and cytology, we downgraded 24 (24%) CIN2 biopsies, three (14%) HSIL, five (83%) ASC-H, and 12 (92%) LSIL-H. One-third of our negative cones can be attributed to overdiagnosis either on biopsy or cytology. Patients with negative cones were older and had smaller excisions, negative colposcopic findings, and negative/equivocal high-risk human papillomavirus (HR-HPV). Within 2 years, 35 (25%) women with negative cones experienced ASCUS or LSIL. Only one (0.7%) recurred as CIN3, a significantly lower percentage than women with positive cones (13%).

CONCLUSIONS

We advocate careful review of all excision-triggering biopsy and cytology, especially in cases of LSIL-H. Patients with negative cones should be surveyed with cytology and HR-HPV testing.

Significance of cytopathologist's review of Pap tests screened as negative for intraepithelial lesion or malignancy that are positive for high-risk human papillomavirus

INTRODUCTION

Cytopathologist's review of Papanicolaou tests (PTs) screened by cytotechnologists as negative for intraepithelial lesion or malignancy (NILM) that are positive for high-risk human papillomavirus (hrHPV+) may be a useful quality control measure.

MATERIALS AND METHODS

From January 1, 2012 to December 31, 2012 all NILM/hrHPV+ PTs underwent cytopathologist's review before report issuance as per routine quality control procedures. HrHPV status was known at the time of screening and at final review. The rate of upgraded diagnoses resulting from the cytopathologist's review were examined. Two-year follow-up was obtained.

RESULTS

Cytopathologist's review upgraded 250 of 1282 PTs (19.5%) by 1 step to atypical squamous cells of undetermined significance and 13 (1%) were upgraded by 2 steps or more to low-grade squamous intraepithelial lesion or higher. During the same period, significantly fewer NILM PTs (of unknown hrHPV status) were upgraded by 2 steps or more as a result of random 10% rescreening by cytotechnologists (0.2%, P < 0.001). Follow-up was available in 740 of 1282 patients (57.7%). The upgraded group was significantly more likely to be referred for colposcopy (68.3% versus 30.5%, P < 0.001) and cervical intraepithelial neoplasia (CIN) 2 or higher (CIN2+) was diagnosed in more upgraded patients (8.9% versus 3.0%, P < 0.01) than in those not upgraded. There was no significant difference in the percentage of colposcopy patients diagnosed with CIN2+ in the 2 groups, respectively (13.1% versus 9.8%, P = 0.47).

CONCLUSIONS

cytopathologist's review of NILM/hrHPV+ PTs identified more 2-step discrepancies than routine 10% rescreening. Significantly more patients in the upgraded group were found to harbor CIN2+; however, this could be related to the higher rate of referral to colposcopy in this group.

Cervical cancer screening and follow-up in 4 geographically diverse US health care systems, 1998 through 2007

BACKGROUND

Cervical cancer screening and follow-up guidelines have changed considerably in recent years, but to the authors' knowledge few published reports exist to estimate the impact of these changes in community-based settings. The authors examined the patterns and results of cervical cancer testing and follow-up over a decade in 4 geographically diverse US health care systems to inform the future evaluation of changes resulting from increased uptake of the human papillomavirus (HPV) vaccination.

METHODS

The authors studied women aged 21 to 65 years who were members of one of these health systems at any time between 1998 and 2007. Data were collected and standardized across sites, based on receipt of Papanicolaou (Pap) and HPV tests, HPV vaccination, cervical biopsies, and treatment of cervical dysplasia. Annual rates (per 1000 person-years) of Pap testing, HPV testing, and cervical biopsy and treatment procedures were calculated. Screening intervals and trends in the results of screening Pap tests and cervical biopsies also were examined.

RESULTS

Pap testing rates decreased (from 483 per 1000 person-years in 2000 to 412 per 1000 person-years in 2007) and HPV testing rates increased over the study period. Screening frequency varied across health care systems, and many women continued to receive annual testing. All 4 sites moved to less frequent screening over the study period without marked changes in the overall use of cervical biopsy or treatment.

CONCLUSIONS

Despite differences over time and across health plans in rates of cervical cancer testing and follow-up cervical procedures, the authors found no notable differences in Pap test results, diagnostic or treatment procedure rates, or pathological outcomes. This finding suggests that the longer screening intervals did not lead to more procedures or more cancer diagnoses.

Utility of liquid-based cytologic examination of distal esophageal brushings in the management of Barrett esophagus: a prospective study of 45 cases

INTRODUCTION

The goal of Barrett esophagus surveillance is to identify high-grade dysplasia (HGD) for eradication. Surveillance programs currently rely on limited histologic sampling; however, the role of cytology in this setting is not well studied.

MATERIALS AND METHODS

From December 1, 2011 to March 30, 2014, 45 patients underwent 4 circumferential brushings of the distal tubular esophagus followed by standard 4-quadrant biopsies. One ThinPrep slide and 1 Cellient cellblock (Hologic, Boxborough, Mass) were prepared. Six cytopathologists evaluated each for adequacy, intestinal metaplasia (IM) and dysplasia. Findings were classified using the traditional 5-tier system used for biopsies. A prospectively modified 3-tier cytologic classification was also tested: negative for HGD, indeterminate for HGD, and HGD. Sensitivity, specificity, and kappa values (interobserver agreement) for cytology were calculated.

RESULTS

Ten of 45 patients had nondiagnostic cytologies; none of whom had dysplasia on biopsy. Cytology had good sensitivity (82%) and specificity (88%) for identifying IM compared with biopsy with moderate interobserver agreement (pairwise average of Fleiss and Krippendorf kappa value = 0.589, 79% agreement). One case had IM on cytology not detected on histology. Six of 45 patients had dysplasia on biopsy including 1 intramucosal adenocarcinoma, 1 indeterminate for dysplasia, 2 high-grade dysplasias, and 2 low-grade dysplasias. A non-negative adequate cytology sample had a sensitivity of 100% and a specificity of 88% and 94% for the 5-tier and the 3-tier classification, respectively.

CONCLUSIONS

Cytology appears to have good sensitivity and specificity for diagnosis of HGD, and cytology may be poised to synergize with advances in other techniques for management of patients with Barrett esophagus. Improvements in brushing devices may help to decrease the nondiagnostic rate.

Follow-up and clinical significance of unsatisfactory liquid-based Papanicolaou tests

BACKGROUND

To the authors' knowledge, few studies to date have examined adherence to recommended guidelines for follow-up and outcomes after an unsatisfactory Papanicolaou (Pap) test (UPT) with liquid-based technologies.

METHODS

Within 4 US health plans, the median time to follow-up and the percentage of patients with follow-up testing by 120 days was calculated after a UPT. Multivariable analyses evaluated the association between clinical factors and follow-up testing. The authors compared the risk of a diagnosis of cervical intraepithelial neoplasia of type 2 or worse (CIN2+) after a UPT with the risk after a satisfactory Pap test while controlling for study site, test year, and other covariates.

RESULTS

A total of 634,644 Pap tests performed between 2004 and 2010 were included in the current study. Of 1442 UPTs, 53.4% had follow-up testing within 120 days; follow-up differed across the health plans (P<.001) and was found to be higher among patients aged <50 years (57.2% vs 48.8%; P = .01) and those with positive human papillomavirus (HPV) results (84.6% vs 53.9; P <.01). The risk of CIN2+ was similar for patients with both unsatisfactory and satisfactory Pap tests. However, after a UPT, the variables of age <50 years, having no previous history of Pap testing, having a history of a previous abnormal Pap test, and positive HPV status were all found to be risk factors for CIN2+; a positive HPV test was found to be the strongest risk factor for developing CIN2+. A negative HPV test result was protective for a CIN2+ diagnosis.

CONCLUSIONS

Various clinical factors associated with the risk of CIN2+ appear to influence the receipt of follow-up after a UPT. HPV test results in patients with UPTs might be used in follow-up strategies; specifically, a negative test result might reduce the urgency for repeat Pap testing.

Cytologic diagnosis of metastatic alveolar rhabdomyosarcoma to the thyroid gland by fine-needle aspiration

BACKGROUND

Metastases to the thyroid gland, although rare, are important entities to consider when evaluating malignant cells on a thyroid fine-needle aspiration (TFNA) specimen. Cellular TFNA specimens with small round blue cells should prompt a broad differential: florid lymphocytic thyroiditis, lymphoma, metastases, as well as primary thyroid malignancies with similar morphologies such as poorly differentiated (insular) and medullary carcinomas. Age, clinical presentation and prior history must be considered in every case.

CASE REPORT

We report, to the best of our knowledge, the first case of metastatic alveolar rhabdomyosarcoma (ARMS) to the thyroid gland, definitively diagnosed by TFNA. A 21-year-old female patient presented with a large mass in the right lobe of the thyroid. Her past history was significant for ARMS diagnosed 24 months earlier, currently in remission after successfully completing 40 weeks of chemoradiation therapy. The diagnosis of metastatic ARMS in the TFNA prompted a more thorough examination revealing previously unknown additional sites of metastases.

CONCLUSION

Metastases to the thyroid gland are uncommon but should be considered in cases where atypical morphology is encountered. Small round blue cell tumors can metastasize to the thyroid gland, and clinical presentation, morphology, immunohistochemistry and molecular studies are helpful in differentiating between them.

Intranuclear cytoplasmic inclusions are a specific feature of intraductal papillary mucinous neoplasms that distinguish contaminating gastric epithelium

INTRODUCTION

Low-grade intraductal papillary mucinous neoplasms (IPMN) are challenging to diagnose because of an absence of reliable morphologic or immunohistochemical features to distinguish them from contaminating gastric foveolar epithelium. After noting intranuclear cytoplasmic inclusions (ICIs) in some cases of IPMN, we investigated whether ICIs could be used as a specific feature to distinguish IPMN from gastric foveolar epithelium.

MATERIALS AND METHODS

A consecutive cohort of 61 transduodenal endoscopic fine-needle aspirations of histologically or clinically verified pancreatic IPMNs without high-grade dysplasia from 2005 to 2012 were identified. A control cohort of 24 endoscopic fine-needle aspirations containing gastric epithelium was selected from transgastric specimens of nonpancreatic targets from the same period. Every fragment of mucinous epithelium in the 2 cohorts was examined in alcohol-fixed and cell block sections at high magnification to identify ICIs.

RESULTS

ICIs were observed in 31% (19 of 61) of cases in mucinous epithelial fragments obtained by fine-needle aspirations from low-grade IPMNs. When present, they were seen in about 1% of all cells. No ICIs were identified in the control cohort of 24 patients with normal gastric epithelium (P = 0.001 Fisher exact test). BRAF mutation (V600E) testing was performed on 5 IPMN cases, and was negative in all cases including 2 with and 3 without ICIs. KRAS mutation testing was performed on 9 cases of IPMN cases. Two cases with ICIs tested positive for KRAS mutations. Four cases without ICIs also tested positive, and 3 cases without ICIs tested negative.

CONCLUSIONS

ICIs are a specific morphologic feature found in about one third of low-grade IPMNs, but absent in gastric foveolar epithelium. There is no obvious molecular correlate with the presence of ICIs.

Patterns in Immunohistochemical Usage in Extended Core Prostate Biopsies: Comparisons Among Genitourinary Pathologists and Nongenitourinary Pathologists

Context.—Immunohistochemical (IHC) stains have known utility in prostate biopsies and are widely used to augment routine staining in difficult cases. Patterns in IHC utilization and differences based on pathologist training and experience is understudied in the peer-reviewed literature.

Objectives.—To compare the rates of IHC usage between specialized (genitourinary; [GU]) and nonspecialized (non-GU) pathologists in extended core prostate biopsies (ECPBs) and the effects of diagnosis; and in cancer cases Gleason grade, disease extent, and perineural invasion on the rate.

Design.—Consecutive ECPBs from 2009–2011 were identified and billing data were used to determine the number of biopsies and IHC stains per case. Diagnoses were mapped and in cancer cases, Gleason grade, extent of disease, and perineural invasion were recorded. Pathologists were classified as GU or non-GU on the basis of training and experience.

Results.—A total of 618 ECPBs were included in the study. Genitourinary pathologists ordered significantly fewer IHC tests per case and per biopsy than non-GU pathologists. The rate of ordering was most disparate for biopsies of cancerous and benign lesions. For biopsies of cancerous lesions, high-grade cancer, bilateral disease, and perineural invasion decreased the rate of ordering in both groups. In cancer cases, GU pathologists ordered significantly fewer stain tests for highest Gleason grade of 3 + 3 = 6, for patients with focal disease and for patients with multiple positive bilateral cores. The effect of the various predictors on IHC ordering rates was similar in both groups.

Conclusions.—Genitourinary pathologists ordered significantly fewer IHC stain tests than non-GU pathologists in ECPBs. Guidelines to define when IHC workup is necessary and not necessary may be helpful to guide workups.

Clinical implications of current developments in genitourinary pathology

CONTEXT

Several developments in genitourinary pathology are likely to change our understanding and management of some genitourinary cancers considerably.

OBJECTIVE

To review 5 stories in genitourinary pathology: (1) fusion in the ETS (E26) gene family in prostatic adenocarcinoma; (2) insulin-like growth factor II messenger RNA-binding protein 3 (IMP3), an important prognostic biomarker for kidney and bladder cancers; (3) translocation renal cell carcinoma; (4) UroVysion fluorescence in situ hybridization test in urine cytology for detection of bladder cancer; and (5) the use of triple immunostaining for diagnosis of prostate cancer.

DATA SOURCES

Literature review and authors' personal experiences.

CONCLUSIONS

Many scientific findings have contributed recently to the understanding of the natural pathogenesis and progression of genitourinary cancers. This translational research helps in diagnosing, predicting, and potentially, treating genitourinary cancers.

Effects of transitioning from conventional methods to liquid-based methods on unsatisfactory Papanicolaou tests: results from a multicenter US study

BACKGROUND

Papanicolaou (Pap) testing has transitioned from conventional preparations (CPs) to liquid-based preparations (LBPs) because of the perceived superiority of LBPs. Many studies conclude that LBPs reduce unsatisfactory Pap tests; however, some believe that the evidence substantiating this claim is weak. The authors studied the effect of the transition from CPs to LBPs on the proportion of unsatisfactory Pap tests in 4 health care systems in the United States participating in the National Institutes of Health-funded Screening Effectiveness and Research in Community-Based Healthcare (SEARCH) project.

METHODS

The study cohort consisted of 548,174 women ages 21 to 65 years who had 1443,725 total Pap tests between 2000 and 2010. Segmented regression analysis was used to estimate the effect of adopting LBPs on the proportion of unsatisfactory Pap tests after adjusting for age.

RESULTS

Three sites that implemented SurePath LBP experienced significant reductions in unsatisfactory Pap tests (estimated effect: site 1, -2.46%; 95% confidence interval [CI], -1.47%, -3.45%; site 2, -1.78%; 95% CI, -1.54%, -2.02%; site 3, -8.25%; 95% CI, -7.33%, -9.17%). The fourth site that implemented ThinPrep LBP did not experience a reduction in unsatisfactory Pap tests. The relative risk of an unsatisfactory Pap test in women aged ≥ 50 years increased after the transition to LBPs (SurePath: relative risk, 2.1; 95% CI, 1.9-2.2; ThinPrep: relative risk, 1.7; 95% CI, 1.5-2.0).

CONCLUSIONS

The observed changes in the proportion of unsatisfactory Pap tests varied across the participating sites and depended on the type of LBP technology, the age of women, and the rates before the implementation of this technology.

A review of reporting systems and terminology for urine cytology

Urine cytology continues to play an important role in the diagnosis and management of urothelial carcinoma, a common cancer of adults with significant morbidity and mortality. Because of its high sensitivity for high-grade urothelial tumors, including lesions that may be cystoscopically occult, urine cytology nicely compliments cystoscopic examination, a method that detects most low-grade tumors. Over the decades, several reporting schemes for urine cytology have been published in the literature, each of which has relative strengths and weaknesses. Unlike cervical cytology, there has not been widespread acceptance and use of any particular reporting scheme for urine cytology studies. Thus, terminology and criteria for urine cytology reporting are not uniform among pathologists, which can frustrate clinicians and hinders interlaboratory comparisons.

The Johns Hopkins Hospital template for urologic cytology samples: parts II and III: improving the predictability of indeterminate results in urinary cytologic samples: an outcomes and cytomorphologic study

BACKGROUND

Urine cytology represents a major portion of testing volume in many cytopathology laboratories.

METHODS

The authors previously reported a template designed to standardize urothelial diagnostic categories to enable clinicians to uniformly manage their patients. In this study, they examined the common cytomorphologic features observed in specimens diagnosed with atypical urothelial cells, cannot exclude high-grade urothelial carcinoma (AUC-H), which prove most predictive of high-grade urothelial carcinoma (HGUC).

RESULTS

The most common morphologic features observed in the AUC-H specimens were hyperchromasia, irregular nuclear borders, increased nucleus-to-cytoplasm ratio, and anisonucleosis. Of the 58 patients who had specimens diagnosed with AUC-H, 95% ultimately were diagnosed with HGUC on follow-up biopsy over the study period. The small number of patients who had AUC-H with non-HGUC follow-up did not allow for a statistical comparison to determine the predictive ability of the selected criteria for HGUC. Next, the authors used the same features to examine a subset of urine samples that were diagnosed with atypical urothelial cells of unknown significance (AUC-US) in an attempt to improve the predictive value of this clinically frustrating category. A blind review was performed of 290 urine specimens from 217 patients. In contrast to the AUC-H specimen cohort, the majority of specimens with AUC-US did not contain atypical cells with the 4 common morphologic features. All 4 features significantly predicted HGUC in surveillance patients, but not in patients with hematuria.

CONCLUSIONS

Hyperchromasia was the strongest predictor of HGUC by far in patients who were undergoing surveillance (odds ratio, 9.81). Hyperchromasia remained statistically significant in multivariate analysis, indicating its predictive strength even in the absence of other features.

Polyphenolic profiles detected in the ripe berries of Vitis vinifera germplasm

Polyphenolic profiles in the berry samples of 344 European grape (Vitis vinifera) cultivars were evaluated for two consecutive years. These cultivars represent a diverse collection of V. vinifera germplasm maintained at the USDA-Agricultural Research Service Vitis Clonal Repository in Davis of California, USA. A total of 36 polyphenolic compounds, including 16 anthocyanins, 6 flavonols, 6 flavanols, 6 hydroxycinnamic acids and 2 hydroxybenzoic acids, were identified via HPLC-MS and quantified by HPLC-DAD. The mean contents for anthocyanins, flavanols, flavonols, hydroxycinnamic acids and hydroxybenzoic acids were 0.946 (coloured cultivars), 0.147, 0.043, 0.195 and 0.016mgg(-1) FW, respectively. On average, wine grapes had higher concentrations than had table grapes for all of these compounds except hydroxycinnamic acids. Berry colours affected the total contents of anthocyanins, but not others. Positive correlations (0.151-0.535) were found among these groups of compounds. As expected, these groups of compounds were all negatively correlated with berry weight.

Combined carcinoid tumor and squamous cell carcinoma of lung: expanding the spectrum of combined tumors of lung

Combined lung cancers containing both small cell and non-small cell carcinoma elements are uncommon but well recognized. Lung tumors with neuroendocrine differentiation form a group of histologically distinct tumors with differing clinical behavior ranging from low-grade tumors with good prognosis (typical carcinoid) to intermediate-grade tumors (atypical carcinoid) to high-grade tumors with poor prognosis (small cell carcinoma and large cell neuroendocrine tumors). The authors report clinical findings and pathologic findings in a case of combined carcinoid tumor and squamous cell carcinoma of lung. To the best of the authors' knowledge, this is the first report of such a case in the peer reviewed literature, thus broadening the spectrum of combined lung tumors.

Genetic structure and domestication history of the grape

The grape is one of the earliest domesticated fruit crops and, since antiquity, it has been widely cultivated and prized for its fruit and wine. Here, we characterize genome-wide patterns of genetic variation in over 1,000 samples of the domesticated grape, Vitis vinifera subsp. vinifera, and its wild relative, V. vinifera subsp. sylvestris from the US Department of Agriculture grape germplasm collection. We find support for a Near East origin of vinifera and present evidence of introgression from local sylvestris as the grape moved into Europe. High levels of genetic diversity and rapid linkage disequilibrium (LD) decay have been maintained in vinifera, which is consistent with a weak domestication bottleneck followed by thousands of years of widespread vegetative propagation. The considerable genetic diversity within vinifera, however, is contained within a complex network of close pedigree relationships that has been generated by crosses among elite cultivars. We show that first-degree relationships are rare between wine and table grapes and among grapes from geographically distant regions. Our results suggest that although substantial genetic diversity has been maintained in the grape subsequent to domestication, there has been a limited exploration of this diversity. We propose that the adoption of vegetative propagation was a double-edged sword: Although it provided a benefit by ensuring true breeding cultivars, it also discouraged the generation of unique cultivars through crosses. The grape currently faces severe pathogen pressures, and the long-term sustainability of the grape and wine industries will rely on the exploitation of the grape's tremendous natural genetic diversity.

Atypical follicular cells with equivocal features of papillary thyroid carcinoma is not a low-risk cytologic diagnosis

OBJECTIVE

To determine whether or not significant differences in the risk of malignancy exist between subgroups of atypical follicular cells in The Bethesda System for Reporting Thyroid Cytology (TBSRTC) in patients who underwent surgical resection.

STUDY DESIGN

Between 2004 and 2009, consecutive thyroid fine-needle aspirates at our institutions with a cytologic diagnosis of 'atypical follicular cells' were retrieved and subclassified using the diagnosis and diagnostic comment as: (1) atypical follicular cells with equivocal features of papillary carcinoma [cannot exclude papillary thyroid carcinoma (PTC)] and (2) atypical follicular cells, other patterns. The risks of malignancy for excised nodules were calculated and comparisons were made between these subgroups. Categorical analysis was performed using a 2-tailed Fisher's exact test, and p < 0.05 was considered statistically significant.

RESULTS

A total of 7,072 thyroid fine-needle aspiration cases were retrieved, with 1,542 (21.8%) having a histologic follow-up. There were 222 (3.1%) cases of 'atypical follicular cells', with 127 (57.2%) having a histologic correlation and 33 having confirmed malignancies. Atypical follicular cells, cannot exclude PTC, have a significantly higher risk of malignancy than atypical follicular cells, other patterns (45.8 vs. 13.9%, p < 0.01).

CONCLUSIONS

Atypical follicular cells with equivocal features of papillary carcinoma is not a low-risk cytologic diagnosis.

Thyroid bed fine-needle aspiration: experience at a large tertiary care center

Fine-needle aspiration (FNA) of thyroid bed (TB) lesions is a common diagnostic modality in monitoring patients for recurrent cancer after a thyroidectomy. To elucidate the value of TB FNA, we reviewed our experience at The Johns Hopkins Hospital, Baltimore, MD. We identified 57 TB FNA specimens from 50 patients. Of the patients, 36 were being followed up for papillary carcinoma, 7 for medullary carcinoma, 4 for follicular carcinoma (1 also had papillary carcinoma), and 1 for poorly differentiated neuroendocrine carcinoma; 3 had previous benign diagnoses. TB FNA yielded diagnostic material in 49 of 57 cases. Of 37 malignant or atypical FNA samples, 32 had surgical follow-up; 30 of 32 were confirmed malignant. The FNA result was benign in 12 of 57, including 6 cases of benign thyroid and 1 case of parathyroid tissue. Immunohistochemical staining was contributory in 5 of 57 cases. TB FNA is a highly reliable tool for diagnosing recurrent thyroid carcinoma. Residual benign thyroid and parathyroid tissue are potential pitfalls; awareness of these and judicious use of immunohistochemical staining can prevent misdiagnoses.

Genomic amplification of the Gret1 retroelement in white-fruited accessions of wild vitis and interspecific hybrids

Retrotransposons are retrovirus-related mobile sequences that have the potential to replicate via RNA intermediates and increase the genome size by insertion into new sites. The retroelement, Gret1, has been identified as playing a key role in generating fruit color variation in cultivated grape (Vitis vinifera L.) due to its insertion into the promoter of VvMybA1. Fruit color variation is an important distinguishing feature of cultivated grapes and virtually no fruit color variation is observed in wild grape species. The presence and relative copy number of Gret1 was assessed using quantitative PCR on 22 different Vitis species, only four of which (plus interspecific hybrids) are known to contain white accessions. Gret1 copy number was observed to vary by species as well as by color within species and was significantly higher in white-fruited accessions across all taxa tested. Additionally, genomic regions surrounding Gret1 insertion were sequenced in white V. vinifera, hybrid, V. labrusca, V. aestivalis, and V. riparia accessions.

Mucinous tubular and spindle cell carcinoma of the kidney: cytopathologic findings

A 54-year-old woman was hospitalized for flank pain and acute renal failure when imaging studies revealed a 5.2 cm mass in the left kidney. She was referred for fine needle aspiration of the lesion, which showed an epithelial tumor with round to oval nuclei associated with strands of metachromatic stromal tissue. Cytopathologic diagnosis was consistent with renal cell carcinoma. Subsequent nephrectomy was performed and the surgical pathology specimen showed a mucinous tubular and spindle cell carcinoma of the kidney. The patient has done well post-operatively with 10 months of benign follow-up.

"Low-grade squamous intraepithelial lesion, cannot exclude high-grade squamous intraepithelial lesion" is a distinct cytologic category: histologic outcomes and HPV prevalence

We examined the histologic outcomes and prevalence of high-risk human papillomavirus (HR-HPV) in women with liquid-based Papanicolaou (Pap) tests interpreted as "low-grade squamous intraepithelial lesion, cannot exclude high-grade squamous intraepithelial lesion" (LSIL-H) compared with the 2001 Bethesda System (TBS 2001) cytologic categories of LSIL, high-grade SIL (HSIL), and atypical squamous cells, cannot exclude HSIL (ASC-H). A computer search identified 426 LSIL, 86 ASC-H, 81 LSIL-H, and 110 HSIL cytologic interpretations during a 1-year period, each with up to 2 years of histologic follow-up. The risk of histologic cervical intraepithelial neoplasia (CIN) 2 or worse (CIN 2+) associated with LSIL-H (32/81 [40%]) was intermediate between LSIL (46/426 [10.8%]) and HSIL (72/110 [65.5%]), but not significantly different from ASC-H (23/86 [27%]). However, LSIL-H was more frequently associated with a definitive histologic diagnosis of any CIN (CIN 1+) than ASC-H (53/81 [65%] vs 35/86 [41%]). Moreover, the prevalence of HR-HPV was significantly greater in patients with LSIL-H than in patients with ASC-H (15/15 [100%] vs 43/73 [59%]). The histologic outcomes and HR-HPV prevalence associated with LSIL-H differ significantly from the established categories of TBS 2001 and provide evidence to support the recognition of LSIL-H as a distinct cytologic category.

Deep fibromatosis (desmoid tumor): cytopathologic characteristics, clinicoradiologic features, and immunohistochemical findings on fine-needle aspiration

BACKGROUND

Deep fibromatosis or desmoid tumor (DF/DT) is a low-grade, soft tissue lesion that is notable for its infiltration and local recurrence and its inability to metastasize. Although the histologic features of DF/DT are well described, there is a paucity of literature regarding cytologic findings.

METHODS

The surgical pathology files of The Johns Hopkins Hospital revealed 17 patients with a diagnosis of DF/DT with prior cytology in a 16-year period (1989-2005). The clinicoradiologic findings were noted, and the fine-needle aspiration (FNA) slides were available for review in 8 patients. In patients with archived tissue, an immunohistochemical panel was performed that included beta-catenin, desmin, CD-34, and c-kit.

RESULTS

There was a wide age range and a wide range of anatomic distribution for DF/DT in this series. Eleven patients (65%) had a prior history of surgery at or near the site of DF/DT. Radiologically, 5 of 11 patients (45%) who had in-house studies available and no history of DF/DT were diagnosed as suspicious for malignancy. Predominantly bland spindled cells with long, fusiform nuclei and metachromatic matrix material were present in most tumors. The tumor cells were present both singly and as fragments embedded in the matrix. Nine patients had paraffin-embedded tissue samples available for immunohistochemical staining. Six of those samples demonstrated nuclear beta-catenin reactivity, and all 9 samples were negative for desmin, CD-34, and c-kit.

CONCLUSIONS

The current results indicated that clinical history in patients with suspected DF/DT is important. Because of the infiltrative nature of DF/DT, the radiographic impression often is over-called as suspicious for malignancy. The cytomorphology is nonspecific, often resulting in descriptive diagnoses. Immunohistochemical stains increase the yield of FNA.

Distinguishing prostatic from colorectal adenocarcinoma on biopsy samples: the role of morphology and immunohistochemistry

CONTEXT

Poorly differentiated carcinoma on prostate or colorectal biopsy can occasionally present a diagnostic challenge in determining tumor source especially in locally advanced colorectal carcinoma (CRCa) or prostate carcinoma (PCa). Such determination can affect prognosis and therapy.

OBJECTIVE

To evaluate the role of morphology and immunohistochemistry in the previously mentioned setting.

DESIGN

Surgical pathology and consultation records. Hematoxylin-eosin sections were reviewed in 16 cases (11 PCa, 5 CRCa). Immunohistochemistry for 9 markers was performed in 15 cases.

RESULTS

Dirty necrosis, seen in 5 (100%) of 5 CRCa and 2 (18%) of 11 PCa cases, and the presence of columnar cells with basal nuclei, seen in 5 (100%) of 5 CRCa and 1 (9%) of 11 PCa cases, appear to be the most useful morphologic parameters. Immunohistochemistry confirmed the value of prostate-specific antigen (PSA), CDX2, cytokeratin (CK) 20, and beta-catenin in the differential of CRCa (0% PSA+, 60% CDX2+, 80% CK20+, and 100% beta-catenin+) versus PCa (80% PSA+, 0% CDX2+, 10% CK20+, and 0% beta-catenin+). P501S had a similar sensitivity as PSA in detecting PCa (80%). Two (20%) of 10 PCa cases were positive for 1 of the 2 markers but not the other. P501S was negative in all 5 cases of CRCa.

CONCLUSIONS

P501S is a useful marker in this setting when included together with PSA, CDX2, CK20, and beta-catenin. P501S labels a subset of PCa cases that are negative for PSA. Dirty necrosis and/or columnar cells with basal nuclei could also be of help.

Significance of Denuded Urothelium in Papillary Urothelial Lesions

Flat urothelial carcinoma in situ (CIS) is often characterized by prominent dyscohesion with some cases having only a few clinging CIS cells remaining on biopsy. The finding of extensive denudation on urothelial biopsies is associated with a risk of CIS on either prior or subsequent biopsies. The significance of denudation in papillary urothelial lesions has not been formally studied. We identified from our surgical pathology files 31 specimens (from 28 patients) of papillary urothelial lesions with extensive denudation. In cases in which denudation was associated with low-grade urothelial neoplasms, follow-up of subsequent cytologic and histologic specimens was obtained. Of the 28 patients, 25 (89%) were men and 3 (11%) were women with an age range of 40 to 88 years old (mean age 62). Of 31 biopsies, 15 were from anatomically confined areas (ie, renal pelvis, ureter, and urethra). In 22/28 (79%) patients, prominent denudation was associated with high-grade papillary carcinomas, 4/28 (14%) low-grade papillary carcinomas, and 2/28 (7%) papillary urothelial neoplasms of low-grade malignant potential. The average extent of urothelial denudation was 82% with 61% of cases having > or =90% denudation. Prominent cautery artifact was present in 17/31 (55%) cases. In 13/28 patients with high-grade lesions, there was a concurrent biopsy of a second urothelial lesion that was either high-grade papillary urothelial carcinoma or invasive urothelial carcinoma. Five of the 6 patients in which the prominent denudation was associated with a low-grade papillary urothelial lesion have not progressed to a high-grade lesion. One patient with a denuded papillary urothelial neoplasm of low malignant neoplasm was subsequently diagnosed with a noninvasive low-grade papillary urothelial carcinoma in the bladder and a high-grade infiltrating urothelial carcinoma of the ureter. We conclude that (1) the majority of papillary urothelial lesions associated with prominent urothelial denudation are high grade; (2) a significant percentage of papillary urothelial lesions with denudation occur with either prominent cautery artifact or in anatomically confined areas, suggesting both iatrogenic and mechanical contributing factors, respectively; (3) a minority of cases with prominent urothelial denudation occur in association with low-grade papillary urothelial lesions and are not associated with progression to higher grade lesions on follow-up studies; and (4) prominent urothelial denudation in papillary lesions should prompt careful examination of these specimens for rare clinging high-grade carcinoma cells, although in a minority of cases the underlying lesion will be low grade.

Wine grape (Vitis vinifera L.) color associates with allelic variation in the domestication gene VvmybA1

During the process of crop domestication and early selection, numerous changes occur in the genetic and physiological make-up of crop plants. In grapevine (Vitis vinifera) numerous changes have occurred as a result of human selection, including the emergence of hermaphroditism and greatly increased variation in berry color. This report examines the effect of human selection on variable skin color by examining the variation present in the gene VvmybA1, a transcriptional regulator of anthocyanin biosynthesis. In over 200 accessions of V. vinifera, the insertion of the retroelement Gret1 in the promoter region of VvmybA1 was in strong association with the white-fruited phenotype. This retroelement was inserted at the same location for each individual in which it was present. Additional polymorphisms in the VvmybA1 gene were also strongly associated with red or pink fruited accessions, including variation that was generated by the excision of Gret1 from the promoter of VvmybA1. Differences in nucleotide diversity were observed between the white and pigmented alleles of VvmybA1, suggesting that the white allele arose only once or a limited number of times. Rarely, association of Gret1 with the white fruited phenotype was not observed, suggesting that the white phenotype can also be obtained through mutation in additional genes. These results provide evidence that variation in one transcriptional regulator has generated an allelic series strongly associated with fruit color variation in cultivated grapevine. These findings provide information about the evolution of grapes since domestication and have direct implications for the regulation of fruit and wine quality of this important crop plant.

Cytopathologic findings in “POEMS” syndrome associated with Castleman disease

A 34-year-old man with a history of a scorpion bite followed by increasing polyneuropathy and IgG lambda monoclonal gammopathy was referred for fine-needle aspiration of a lytic bone lesion and an enlarged axillary lymph node. The findings in the bone lesion were consistent with a plasmacytoma. The FNA of the lymph node showed a peculiar capillary proliferation in a background of polymorphous mature lymphocytes. Flow cytometric analysis showed a mixed lymphoid population. The lymph node was originally signed out descriptively, but review of the case showed features consistent with Castleman disease. After the pathologic findings and clinical features were discussed with the clinical team, the diagnosis of POEMS syndrome was established. Subsequent surgical excision of the lymph node was diagnosed as hyaline vascular-variant Castleman disease.

Histologic and electron microscopy findings in myocardium of treated Fabry disease

The well-described histologic and electron microscopic findings in Fabry disease cardiomyopathy are hypertrophic vacuolated cells with electron dense concentric lamellar bodies. We present altered findings in an endomyocardial biopsy from a patient with treated Fabry disease. A 51-year-old male with Fabry disease, treated with recombinant alpha-galactosidase enzyme replacement therapy for over 18 months, underwent an endomyocardial biopsy for heart failure. The histologic changes showed widespread hypertrophy and vacuolization with rare eosinophilic bodies. Electron microscopy failed to reveal the characteristic globotriaosylceramide concentric lamellar bodies (myelin figures) in the sarcoplasm. Instead, extensive aggregates and single tubular crystalline structures, giant secondary lysosomes as well as abnormal branched chain glycogen were present. This is the first histologic description of long-standing treated Fabry disease in cardiac myocytes.

Metastatic breast carcinoma involving the thyroid gland diagnosed by fine-needle aspiration: a case report

Secondary involvement of the thyroid gland from a remote primary malignancy is uncommon. The distinction of metastatic carcinoma (MC) or sarcoma from a primary thyroid malignancy is important because the treatment is different. We discuss a case of a 64-yr-old female with a history of breast carcinoma, who presented with pain and swelling in her neck 5 yrs after being diagnosed with breast cancer. She had undergone mastectomy with subsequent chemotherapy and radiation for infiltrating mammary carcinoma. During the 5-yr interval, she had been free of clinically evident metastatic disease. Subsequent work-up revealed two distinct nodules in the left lobe of her thyroid gland as well as a subcutaneous mass in her right shoulder. A fine-needle aspiration (FNA) of the larger thyroid nodule showed malignant epithelial cells with features consistent with breast carcinoma in a background of benign thyroid epithelial cells and colloid. The case was signed out as metastatic breast carcinoma. Subsequent FNA and biopsy of her right shoulder lesion also revealed metastatic breast carcinoma with similar morphology to the material in the thyroid FNA.

Atypical squamous cells in exfoliative urinary cytology: Clinicopathologic correlates

Presence of atypical squamous cells (ASC) in voided urine is an uncommon finding that may be the harbinger of an underlying malignant process. ASCs in urine may precede a de novo histologic diagnosis of malignancy or be the first sign of a recurrence in the lower urinary tract, or the gynecologic tract (in women). This study analyzed all urine cytology specimens with such diagnoses, with reference to their final histologic outcome. All urine cytology cases (n = 17,446) that included ASCs, evaluated at The Johns Hopkins Hospital between 1989 and 2003 (14 yr), were reviewed for diagnoses. ASCs as defined in this study are keratinizing cells with large and hyperchromatic smudgy nuclei, high N/C ratio, abnormal nuclear or cytoplasmic shapes, and densely orangeophilic cytoplasm. These cases lacked the qualitative and quantitative criteria for malignancy. The final reference outcome was determined by subsequent histologic and clinical follow-up. Of these 17,446 urine specimens, 55 cases (0.3%) from 47 patients had ASCs present. Thirty-two of the 47 patients had adequate follow-up. In 8 of these 32 patients (25%), a diagnosis of squamous-cell carcinoma (SCC) of the urinary bladder or urothelial carcinoma (UC) with squamous differentiation was made on subsequent histologic examination. In two cases (6%) a diagnosis of high-grade cervical SCC was established on subsequent follow-up. Twenty two of 32 cases (69%) remained benign on histologic and prolonged clinical follow-up. We conclude that ASCs in urine are rare (0.3% in this series). An interpretation of ASCs in a urine specimen is made when there is insufficient qualitative/quantitative evidence for a carcinoma diagnosis. ASCs in urine are a clinically valid diagnostic category (31% were later diagnosed with SCC). Most patients with urinary ASCs do not develop malignancy and, therefore, these cells may represent a reactive/inflammatory process most commonly due to vaginal contamination (in women) or exfoliation from the distal urethra (in men). Rarely, ASCs may exfoliate from a uterine cervical SCC and, therefore, a pelvic examination should be considered in such patients.

Alpha coefficient of dose-response for chromosome translocations measured by FISH in human lymphocytes exposed to chronic 60Co gamma rays at body temperature

PURPOSE

To measure the alpha coefficient, the initial slope of the translocation dose-response curve, for 60Co gamma-rays in human lymphocytes.

MATERIALS AND METHODS

Human lymphocytes were exposed to 0, 0.32, 0.62 and 0.92 Gy of chronic 60Co gamma-rays under conditions that reduce the metabolic stress to the cells. Chromosome translocation frequencies were measured using fluorescence in situ hybridization with a whole-chromosome probe cocktail specific for chromosomes 1, 2, 4 (orange) and 3, 5, 6 (green).

RESULTS

A total of 72,383 metaphases were analysed (33,429 in exposed cells) in two individuals. The shape of the dose-response curves for translocations was linear, and alpha coefficient was measured as 0.024 +/- 0.002 translocations per cell per Gy for the combined data for two 24 year old male donors.

CONCLUSION

The alpha coefficients measured after chronic exposure were in good agreement with that reported in the literature for acute, low-dose exposure of human lymphocytes to 60Co gamma-rays.

Theoretical and experimental tests of a chromosomal fingerprint for densely ionizing radiation based on F ratios calculated from stable and unstable chromosome aberrations

In the present study, F ratios for both stable chromosome aberrations, i.e. ratios of translocations to pericentric inversions, and unstable aberrations, i.e. dicentrics and centric rings, were measured using fluorescence in situ hybridization. F ratios for stable aberrations measured after exposure to low (2.89 Gy 60Co gamma rays) and high-LET (0.25 Gy 56Fe ions; 1.25 Gy 56Fe ions; 3.0 Gy 12C ions) radiation were 6.5 +/- 1.5, 4.7 +/- 1.6, 9.3 +/- 2.5 and 10.4 +/- 3.0, respectively. F ratios for unstable aberrations measured after low (2.89 Gy 60Co gamma rays) and high-LET (0.25 Gy 56Fe ions; 3.0 Gy 12C ions) radiations were 6.5 +/- 1.6, 6.3 +/- 2.3 and 11.1 +/- 3.7, respectively. No significant difference between the F ratios for low- and high-LET radiation was found. Further tests on the models for calculation of the F ratio proposed by Brenner and Sachs (Radiat. Res. 140, 134-142, 1994) showed that the F ratio may not be straightforward as a practical fingerprint for densely ionizing radiation.

Site-specific core 1 O-glycosylation pattern of the porcine submaxillary gland mucin tandem repeat. Evidence for the modulation of glycan length by peptide sequence

The sequence-specific O-linked core 1 ([R1, R2]-beta-Gal(1-3)-alpha-GalNAc-O-Ser/Thr) glycosylation pattern has been quantitatively determined for 30 of the 31 Ser/Thr residues in the 81-residue porcine submaxillary gland mucin tandem repeat. This was achieved by Edman amino acid sequencing of the isolated tandem repeat after selective removal of non-C3-substituted, peptide-linked GalNAc residues by periodate oxidation and subsequent trimming of the remaining oligosaccharides to peptide-linked GalNAc residues by mild trifluoromethanesulfonic acid/anisole treatment. The sequencing reveals 61% (range, 12-95%) of the peptide alpha-N-acetylgalactosamine (GalNAc) residues to be substituted by core 1 chains, a value in agreement with the carbon-13 NMR analysis of the native mucin. Residues with the lowest C3 substitution were typically clustered in regions of sequence with the highest densities of (glycosylated) serine or threonine. This suggests that the porcine beta3-Gal, core 1, transferase is sensitive to peptide sequence and/or neighboring core GalNAc glycosylation in vivo, in keeping with earlier in vitro enzymatic glycosylation studies (Granovsky, M., Blielfeldt, T., Peters, S., Paulsen, H., Meldal, M., Brockhausen, J., and Brockhausen, I. (1994) Eur. J. Biochem. 221, 1039-1046). These results demonstrate that the O-glycan structures in mucin domains are not necessarily uniformly distributed along the polypeptide core and that their lengths can be modulated by peptide sequence. The data further suggest that hydroxyamino acid spacing may contribute to the regulation of glycan length, thereby, providing a mechanism for maintaining an optimally expanded, protease resistant, mucin conformation.

Determination of the site-specific O-glycosylation pattern of the porcine submaxillary mucin tandem repeat glycopeptide. Model proposed for the polypeptide:galnac transferase peptide binding site

The heterogeneously glycosylated 81-residue tryptic tandem repeat glycopeptide from porcine submaxillary mucin (PSM) has been isolated and its glycosylation pattern determined by amino acid sequencing. Key to these studies is the ability to trim the structurally heterogeneous PSM oligosaccharide side chains to homogeneous GalNAc monosaccharide side chains by mild trifluoromethanesulfonic acid treatment. Trypsin treatment of trifluoromethanesulfonic acid-treated PSM releases the 81-residue tandem repeat as an ensemble of 81-residue glycopeptides with different glycosylation patterns. Automated amino acid sequencing using Edman degradative chemistry of the repeat was used to determine the extent of glycosylation of nearly every Ser and Thr residue. The Thr residues are all highly glycosylated within the range of 73-90%, giving an average Thr glycosylation of 83%. In contrast, the Ser residues display a wide range of glycosylations, ranging between 33 and 95%, giving an average Ser glycosylation of 74%. These data are consistent with the known elevated glycosylation of Thr peptides over Ser peptides for the porcine UDP-N-acetylgalactosamine:polypeptide N-acetylgalactosaminyltransferase. It is also observed that the extent of glycosylation of the repeat correlates poorly with published predictive methods. An examination of the sequences surrounding the glycosylation sites reveals that nearly all of the highly glycosylated sites have a penultimate Gly residue, whereas those that are less highly glycosylated have medium to large side chain penultimate residues. As observed by others, glycosylation also appears to be modulated by the presence of Pro residues. On the basis of these findings we suggest that the acceptor peptide binds the transferase in a beta-like conformation and that penultimate residue side chain steric interactions may play a role in determining extent that a given Ser or Thr is glycosylated. A model for the GalNAc transferase peptide binding site is proposed.

Characterization of the 46,000-dalton subunit of eIF-4F

Three protein synthesis initiation factors, eukaryotic initiation factor (eIF)-4A, -4B, and -4F are required for the ATP-dependent binding of mRNA to the ribosome. To extend the characterization of the eIF-4A-like subunit of eIF-4F, a cDNA clone encoding eIF-4A has been isolated from a rabbit liver cDNA library and sequenced. The clone is almost full length for the coding region and complete for the 3' noncoding region. The sequence of the rabbit cDNA has been compared to the sequence of the two similar, but not identical, genes and cDNAs encoding mouse eIF-4A (termed eIF-4AI and eIF-4AII). The rabbit cDNA sequence is very similar to the mouse eIF-4AI genomic and liver cDNA sequence with 100% identity at the amino acid level and 90% identity at the nucleotide level within the protein coding region; however, there is very little similarity in the 3' noncoding region. Amino acid sequencing of purified rabbit reticulocyte eIF-4A protein indicates that it is eIF-4AI (encoded by the eIF-4AI gene and cDNA) and none of the amino acid residues sequenced are in disagreement with those predicted from the mouse liver or rabbit liver cDNA sequences. Subsequently, we have analyzed the p46 subunit of eIF-4F, a three subunit protein whose molecular weights have been estimated by sodium dodecyl sulfate gel electrophoresis to be 220,000, 46,000 and 24,000. The p46 subunit has physical properties similar to eIF-4A. This subunit was isolated from rabbit reticulocyte eIF-4F and sequenced chemically. Our results indicate that this peptide is a mixture of eIF-4AI and eIF-4AII in an approximate ratio of 4 to 1, respectively. No eIF-4AII was observed in our rabbit reticulocyte eIF-4A preparation. Therefore we have concluded that either the eIF-4AI and the eIF-4AII proteins were resolved from each other in the purification of rabbit reticulocyte eIF-4A or that eIF-4AII preferentially associates with the p220 and p24 subunits of eIF-4F. Evidence favoring the latter possibility is discussed.

Characterization of protein synthesis factors from rabbit reticulocytes

As part of our efforts to characterize eukaryotic translation factors, we have sequenced a number of them chemically and inferred sequences from cDNA clones. To our surprise, there appears to be extensive identity of amino acid sequence in most factors characterized to date in that within mammalian species, usually greater than 99% identity is observed. Extreme examples are rabbit EF-1 alpha which is 100% identical to human EF-1 alpha and rabbit eIF-4AI and eIF-4AII which are 100% identical to mouse eIF-4AI and eIF-4AII for those amino acids sequenced (398/406 and 156/407, respectively). An extended analysis has been made of EF-1 alpha which in rabbit has three different post-translational modifications, dimethyllysine, trimethyllysine and glycerylphosphorylethanolamine. A comparison of the primary structure of EF-1 alpha to E. coli EF-Tu indicates an overall sequence identity of 33%. However, within the amino terminal 180 amino acids (the GTP-binding domain), there are found regions of much greater identity (50/85 = 59%).

Location of seven post-translational modifications in rabbit elongation factor 1 alpha including dimethyllysine, trimethyllysine, and glycerylphosphorylethanolamine

Amino acid sequencing of a large number of chemical and enzymatic cleavage products of elongation factor 1 alpha purified from rabbit reticulocyte has identified seven post-translationally modified residues. Five of the modifications are methylations of lysine residues yielding dimethyllysine at residues 55 and 165 and trimethyllysine at residues 36, 79, and 318. The two remaining post-translational modifications involve the addition of ethanolamine to glutamic acid residues 301 and 374, as reported previously (Rosenberry, T. L., Krall, J. A., Dever, T. E., Haas, R., Louvard, D., and Merrick, W. C. (1989) J. Biol. Chem. 264, 7096-7099). Fast atom bombardment mass spectrometry and fast atom bombardment tandem mass spectrometry have been used to analyze peptides containing these modified residues. The analyses have determined that glycerylphosphorylethanolamine has been attached to the glutamic acid residues. An analysis of the amino acid sequence surrounding each of the three types of modification has indicated no similarities. Therefore, it seems likely that the modifying enzymes do not recognize a specific amino acid sequence but rather the three-dimensional presentation of either amino or carboxyl residues in the elongation factor 1 alpha structure.