Three-dimensional nuclear architecture distinguishes thyroid cancer histotypes.

Molecular markers can serve as diagnostic tools to support pathological analysis in thyroid neoplasms. However, because the same markers can be observed in some benign thyroid lesions, additional approaches are necessary to differentiate thyroid tumor subtypes, prevent overtreatment and tailor specific clinical management. This applies particularly to the recently described variant of thyroid cancer referred to as noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). This variant has an estimated prevalence of 4.4% to 9.1% of all papillary thyroid carcinomas worldwide. We studied 60 thyroid lesions: 20 classical papillary thyroid carcinoma (CPTC), 20 follicular variant of PTC (FVPTC) and 20 NIFTP. We examined morphological and molecular features to identify parameters that can differentiate NIFTP from the other PTC subtypes. When blindly investigating the nuclear architecture of thyroid neoplasms, we observed that NIFTP has significantly longer telomeres than CPTC and FVPTC. Super-resolved 3D-structured illumination microscopy demonstrated that NIFTP is heterogeneous and that its nuclei contain more densely packed DNA and smaller interchromatin spaces than CPTC and FVPTC, a pattern that resembles normal thyroid tissue. These data are consistent with the observed indolent biological behavior and favorable prognosis associated with NIFTP, which lacks BRAFV600E mutations. Of note, next-generation thyroid oncopanel sequencing was unable to distinguish the thyroid cancer histotypes in our study cohort. In summary, our data suggest that 3D nuclear architecture can be a powerful analytical tool to diagnose and guide clinical management of NIFTP.

Navigating the Blood-Brain Barrier: Challenges and Therapeutic Strategies in Breast Cancer Brain Metastases.

Breast cancer (BC) is the most common cancer in women, with metastatic BC being responsible for the highest number of deaths. A frequent site for BC metastasis is the brain. Brain metastasis derived from BC involves the cooperation of multiple genetic, epigenetic, angiogenic, and tumor-stroma interactions. Most of these interactions provide a unique opportunity for development of new therapeutic targets. Potentially targetable signaling pathways are Notch, Wnt, and the epidermal growth factor receptors signaling pathways, all of which are linked to driving BC brain metastasis (BCBM). However, a major challenge in treating brain metastasis remains the blood-brain barrier (BBB). This barrier restricts the access of unwanted molecules, cells, and targeted therapies to the brain parenchyma. Moreover, current therapies to treat brain metastases, such as stereotactic radiosurgery and whole-brain radiotherapy, have limited efficacy. Promising new drugs like phosphatase and kinase modulators, as well as BBB disruptors and immunotherapeutic strategies, have shown the potential to ease the disease in preclinical studies, but remain limited by multiple resistance mechanisms. This review summarizes some of the current understanding of the mechanisms involved in BC brain metastasis and highlights current challenges as well as opportunities in strategic designs of potentially successful future therapies.

Examination of total hip and knee arthroplasty tissues.

BACKGROUND: Many practices require tissues from hip and knee arthroplasty procedures to be sent for pathologic examination. These examinations rarely provide information beyond the clinical or radiologic diagnosis and rarely alter clinical management. We aimed to determine the rate at which histologic diagnoses based on gross assessment alone or gross plus microscopic assessment correspond with reported clinical diagnoses in patients undergoing total joint arthroplasties and whether the histologic diagnoses alter patient management. METHODS: We retrospectively reviewed arthroplasty cases performed at a high-volume teaching hospital in Manitoba, Canada. The clinical diagnosis was compared with the final pathology report based on gross examination, with or without histologic assessment. The results of the comparison were classified into 3 categories: concordant (same diagnosis), discrepant (different diagnoses without alterations in management) and discordant (different diagnoses resulting in management change). The overall provincial cost for pathologic examination was determined by multiplying the total examination cost by the estimated number of arthroplasty cases. RESULTS: There were 773 patients in our study sample. The concordant rate was 98.3% (95% confidence interval [CI] 97.1%-99.1%), the discrepant rate was 1.7% (95% CI 0.9%-2.9%) and the discordant rate was 0.0% (95% CI 0%-0.5%) for 773 cases. The pathology diagnosis did not alter patient management in any case. A total of 91.5% of specimens did not require full histologic review and received gross descriptions only. The discrepancy rate was higher in cases that included microscopic examination than in those that received only gross descriptions (15.2% v. 0.4%, p < 0.001). The overall provincial cost for pathologic examination was estimated at Can$304 556. CONCLUSION: Submitting routine tissue from arthroplasty procedures to pathology does not affect patient management and therefore provides no value for the health care resources expended in doing so.

CONTEXTE: Beaucoup d'établissements exigent que des tissus soient envoyés pour un examen anatomopathologique après une arthroplastie de la hanche et du genou. Ces examens n'apportent généralement pas d'information nouvelle quant au diagnostic clinique ou radiologique et modifient rarement la prise en charge. Notre objectif était de déterminer le pourcentage de correspondance entre les diagnostics histologiques fondés sur l'inspection grossière uniquement ou sur l'inspection grossière et l'examen au microscope, et les diagnostics cliniques des patients qui subissent des arthroplasties totales. Nous cherchions également à savoir si les diagnostics histologiques modifient la prise en charge. MÉTHODES: Nous avons procédé à une analyse rétrospective d'arthroplasties effectuées dans un grand hôpital universitaire du Manitoba, au Canada. Le diagnostic clinique était comparé au rapport final de pathologie fondé sur une inspection grossière, avec ou sans examen histologique. Les résultats de cette comparaison étaient classés en 3 catégories : concordance (même diagnostic), divergence (diagnostics différents, sans modification de la prise en charge) et discordance (diagnostics différents entraînant une modification de la prise en charge). Le coût global pour la province associé aux examens pathologiques a été établi en multipliant le coût total d'un examen par le nombre estimé de cas d'arthroplastie. RÉSULTATS: Notre échantillon comprenait 773 patients. Le taux de concordance était de 98,3 % (intervalle de confiance [IC] de 95 % 97,1 %­99,1 %), le taux de divergence était de 1,7 % (IC de 95 % 0,9 %­2,9 %) et le taux de discordance de 0,0 % (IC de 95 % 0 %­0,5 %). Dans tous les cas, le diagnostic pathologique n'a pas modifié la prise en charge. Au total, 91,5 % des spécimens ne nécessitaient pas d'examen histologique complet et n'ont fait l'objet que d'une inspection grossière. Le pourcentage d'anomalie était plus élevé pour les spécimens analysés au microscope que pour ceux ayant uniquement subi une inspection grossière (15,2 % c. 0,4 %, p < 0,001). Le coût total des examens pathologiques pour la province a été estimé à 304 556 $ CA. CONCLUSION: L'analyse pathologique systématique de tissus prélevés lors d'arthroplasties n'entraîne pas une modification de la prise en charge du patient; il n'y a donc pas de valeur associée aux ressources de santé utilisées pour ces examens.

Carcinogenesis alters fatty acid profile in breast tissue.

Cancerogenesis is associated with cell membrane changes. The aim of this study was to investigate whether breast tissues with different degrees of cancer involvement have different fatty acid profiles. Fourteen breast cancer patients with a mean age of 61 years were recruited. Morphological features of the tumoral specimens were characterized. Approximately 60 % of patients had invasive ductal carcinoma, and 80 % were ER positive; 65 % were PR positive; and 65 % were HER2 negative. The segments with confirmed cancer had significantly less amounts of total lipids as compared with the corresponding grossly normal or interface tissues. The fatty acid profile in cancer tissue was significantly different from that in other tissues. Fatty acid composition of five classes of phospholipids revealed the variations between cancer tissue and the other two segments. A transition of changes in fatty acid composition in these fractions of phospholipids was observed. The interface tissue had intermediate amounts of several fatty acids including palmitic acid, stearic acid, and arachidonic acid. Interestingly, we observed significantly higher amounts of the n-3 fatty acid DHA in cancer tissue as compared to the other two tissues. Data from this study will provide evidence that biochemical changes particularly phospholipid composition may take place well in advance prior to morphological changes. Should this theory be confirmed by larger studies, deviation of phospholipid composition from normal values can be used as markers of susceptibility of tissue to cancer development.

Intraoperative Communications Between Pathologists and Surgeons: Do We Understand Each Other?

CONTEXT.­: Clear communication between pathologists and surgeons during intraoperative consultations is critical for optimal patient care. OBJECTIVE.­: To examine the concordance of intraoperative diagnoses recorded in pathology reports to surgeon-dictated operative notes and assess the impact of an intervention on the discrepancy rates. DESIGN.­: Discrepancies between the intended communication by pathologists and the interpretation by surgeons were characterized as minor with no crucial clinical impact, and major with the potential of altering patient management. After analysis, a corrective intervention was implemented with education, information sharing, and a change in protocol, and a comparative analysis was conducted. RESULTS.­: We examined 223 surgical cases with 578 intraoperative consultations. In 23% (51) of the cases, the intraoperative diagnosis was not recorded in the operative reports. We found minor discrepancies in 34% (59) and major discrepancies in 2% (3) of the remaining cases. Deferrals accounted for 24% (14 of 59) of the minor and 33% (1 of 3) of the major discrepancies. Among the discrepant cases, 56% (35 of 62) were multipart cases, including all major discrepancies. Following intervention, no major discrepancies were found in 101 cases with 186 intraoperative interpretations. The cases with no operative documentation reports decreased from 23% to 16% (16 of 101). Minor discrepancies were found in 11% (9 of 85) of the cases, indicating significant improvement (P < .001). CONCLUSIONS.­: Intraoperative diagnoses can be miscommunicated and/or misinterpreted, possibly impacting intraoperative management, particularly in multipart cases and those involving deferrals. This study highlights the importance of auditing intraoperative communications and addressing the findings through a local intervention.

An Outbred Guinea Pig Disease Model for Lassa Fever Using a Host-Adapted Clade III Nigerian Lassa Virus.

Nigeria experiences annual outbreaks of Lassa fever (LF) with high case numbers. At least three clades of Lassa virus (LASV) have been documented in Nigeria, though recent outbreaks are most often associated with clade II or clade III viruses. Using a recently isolated clade III LASV from a case of LF in Nigeria in 2018, we developed and characterized a guinea pig adapted virus capable of causing lethal disease in commercially available Hartley guinea pigs. Uniform lethality was observed after four passages of the virus and was associated with only two dominant genomic changes. The adapted virus was highly virulent with a median lethal dose of 10 median tissue culture infectious doses. Disease was characterized by several hallmarks of LF in similar models including high fever, thrombocytopenia, coagulation disorders, and increased inflammatory immune mediators. High viral loads were noted in all solid organ specimens analyzed. Histological abnormalities were most striking in the lungs and livers of terminal animals and included interstitial inflammation, edema, and steatosis. Overall, this model represents a convenient small animal model for a clade III Nigeria LASV with which evaluation of specific prophylactic vaccines and medical countermeasures can be conducted.

Public perceptions on pathology: a fundamental change is required.

Pathology has been mostly invisible for the public. The missing recognition affects the pathologists' reputation, and efforts with recruitment and advocacy. Our survey with 387 respondents confirms that the public knowledge on the role of the pathologists has not improved despite campaigns and advocacy efforts. Pathology was identified as a medical specialty by 79.1% of the respondents. Only 34.8% assumed that it takes more than 8 years of post-high school training to become a pathologist. Most commonly, another medical specialist was identified as the ultimate diagnostician on Pap tests (gynaecologist), breast biopsies or malignant surgical excisions (oncologist), gastrointestinal biopsies (gastroenterologist) or prostate biopsies (urologist). The experience gained by undergoing these procedures had minimal impact on understanding the pathologists' role, since they were identified as ultimate diagnosis makers by the minority of these patients (13.8%-36.4%). The integration of pathologist-interactions into patient care may be a potential solution with benefits beyond improved perceptions.

Effects of long-term consumption of a high-fructose diet on conventional cardiovascular risk factors in Sprague-Dawley rats.

We investigated the effects of a high-fructose (HF) diet on cardiovascular risks in Sprague-Dawley rats. Twelve rats were randomly assigned to standard chow or HF diet for 20 weeks. Systolic blood pressure and circulating insulin, total cholesterol, and triacylglycerol levels were significantly higher in the HF group. Aortic sections appeared normal, but liver sections from the HF group showed lipid accretion, mild inflammation, and bile pigmentation. Liver samples from the HF group showed significantly higher total lipid levels and changes in fatty acid profile. Levels of 16:0, cis-9-18:2, cis-11-20:1, cis-13-20:1, cis-11-20:2 and 24:0 were significantly raised in the phospholipid fraction. Lower levels of cis-11-18:1, cis-9-18:2, and cis-11-20:1 and increased levels of 16:1, cis-9-18:1, and cis-13-20:1 were found in the non-esterified fatty acid fraction. HF-feeding resulted in significant reductions in plasma levels of certain inflammatory biomarkers. HF intake over time may negatively impact cardiovascular health and liver function in rats.

The role of Tissue Doppler imaging in the noninvasive detection of chronic rejection after heterotopic cardiac transplantation in rats.

BACKGROUND: Chronic rejection is a risk factor for the development of cardiac allograft vasculopathy (CAV) in heart transplant recipients. A useful animal model to study the role of immunosuppressive strategies in the prevention of chronic rejection involves heterotopic abdominal cardiac transplantation in rats. The detection of rejection and concurrent CAV traditionally involves subjective serial palpation of the graft from a scale of 0 to 4, with 4 indicating vigorous beats. Recent advances in murine echocardiography, in particular Tissue Doppler imaging (TDI), may allow for objective in vivo monitoring of chronic rejection in this transplant model. OBJECTIVE: The objective of this study was to compare the diagnostic accuracy of murine echocardiography as compared to the abdominal palpation heart score for the noninvasive detection of chronic cardiac graft rejection. METHODS: In an animal model of heterotopic cardiac transplantation, 18 male Fischer and Lewis rats were used as donors and recipients, respectively. Abdominal palpation and murine transthoracic echocardiography were performed to assess in vivo function of the transplanted heart. Left ventricular (LV) structure and function and TDI indices, including endocardial velocity (Vendo) and strain rate (SR), were evaluated in the ectopic heart. Graft tissues were processed for histological examination and graded for chronic rejection. RESULTS: Abdominal palpation scores were obtained in all 18 rats; score 1 (n = 5); score 2 (n = 4); score 3 (n = 6); and score 4 (n = 3). The mean LV ejection fraction was significantly (P <0.01) lower in score 3 and 4 grafts as compared to score 1 grafts. There was no correlation between the abdominal palpation score and LV systolic function. There was a significant relationship between decreasing Vendo or SR values and increasing grades of rejection (r = 0.65, P <0.05 and r = 0.75, P < 0.05, respectively). CONCLUSION: TDI of the transplanted heart in rats is feasible, reproducible, and more sensitive than palpation for the detection of chronic rejection.

Anti-Atherosclerotic Properties of Wild Rice in Low-Density Lipoprotein Receptor Knockout Mice: The Gut Microbiome, Cytokines, and Metabolomics Study.

BACKGROUND AND AIM: We previously reported the anti-atherogenic properties of wild rice in low-density lipoprotein receptor knockout (LDL-r-KO) mice. The present study aimed to discover the mechanism of action for such effects. MATERIALS: Fecal and plasma samples from the wild rice treated and control mice were used. Fecal bacterial population was estimated while using 16S rDNA technology. The plasma samples were used to estimate the levels of 35 inflammatory markers and metabolomics, while using Meso Scale multiplex assay and liquid chromatography-mass spectrometry (LC-MS/MS) techniques. RESULTS: Many bacteria, particularly Anaeroplasma sp., Acetatifactor sp., and Prophyromonadaceae sp., were found in higher quantities in the feces of wild rice fed mice as compared to the controls. Cytokine profiles were significantly different between the plasma of treated and control mice. Among them, an increase in the level of IL-10 and erythropoietin (EPO) could explain the anti-atherogenic properties of wild rice. Among many metabolites tested in plasma of these animals, surprisingly, we found an approximately 60% increase in the levels of glucose in the wild rice fed mice as compared to that in the control mice. CONCLUSION: Additional studies warrant further investigation of the interplay among gut microbiome, inflammatory status, and macronutrient metabolism.

Fit-For-Purpose PD-L1 Biomarker Testing For Patient Selection in Immuno-Oncology: Guidelines For Clinical Laboratories From the Canadian Association of Pathologists-Association Canadienne Des Pathologistes (CAP-ACP).

Since 2014, programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) checkpoint inhibitors have been approved by various regulatory agencies for the treatment of multiple cancers including melanoma, lung cancer, urothelial carcinoma, renal cell carcinoma, head and neck cancer, classical Hodgkin lymphoma, colorectal cancer, gastroesophageal cancer, hepatocellular cancer, and other solid tumors. Of these approved drug/disease combinations, a subset also has regulatory agency-approved, commercially available companion/complementary diagnostic assays that were clinically validated using data from their corresponding clinical trials. The objective of this document is to provide evidence-based guidance to assist clinical laboratories in establishing fit-for-purpose PD-L1 biomarker assays that can accurately identify patients with specific tumor types who may respond to specific approved immuno-oncology therapies targeting the PD-1/PD-L1 checkpoint. These recommendations are issued as 38 Guideline Statements that address (i) assay development for surgical pathology and cytopathology specimens, (ii) reporting elements, and (iii) quality assurance (including validation/verification, internal quality assurance, and external quality assurance). The intent of this work is to provide recommendations that are relevant to any tumor type, are universally applicable and can be implemented by any clinical immunohistochemistry laboratory performing predictive PD-L1 immunohistochemistry testing.

Association of TSC1/hamartin, 14-3-3sigma, and p27 expression with tumor outcomes in patients with pTa/pT1 urothelial bladder carcinoma.

TSC1/hamartin is a tumor suppressor gene involved in the development of various malignancies, including bladder cancer. In vitro studies showed that hamartin controls cell proliferation partly by up-regulating p27 and 14-3-3sigma. This study was designed to explore the value of these biomarkers in predicting outcome in pTa/pT1 tumors and validate the regulation of p27 and 14-3-3sigma by hamartin in vivo using human bladder cancer tissue. A tissue microarray of 134 pTa and pT1 tumors was constructed, and sections were stained with hamartin, 14-3-3sigma, and p27 antibodies. In multiple Cox regression analysis, pTa/pT1 tumors with reduced or low expression of hamartin tended to have higher risk of progression (P = .030). High-grade tumors tended to be at higher risk of progression in comparison with low-grade tumors (P < .001). The combination of expression of these 3 biomarkers did not add predictive value regarding disease outcomes. Low hamartin expression and high tumor grade are independent factors in predicting faster pTa/pT1 tumor progression. In a subset of pTa/pT1 tumors, hamartin has a role in bladder carcinogenesis by positively regulating 14-3-3sigma and p27.

Glandular Cell Abnormalities on SurePath Preparations: A Retrospective Review with Cytology-Histology Correlations.

OBJECTIVE: Detecting glandular lesions is challenging by all Pap test methodologies. As the availability of data on identifying glandular abnormalities by SurePath is scarce, we investigated the detection rates and the correlation with histology follow-up. STUDY DESIGN: A total of 105,927 cases (SurePath and conventional) were searched for the diagnosis of atypical glandular cells or higher glandular abnormalities (AGC+) with the corresponding histologic diagnosis. The associations between the Pap test methods and diagnostic categories were assessed by χ2 test. RESULTS: Overall, 0.32% of SurePath (159/49,375) and 0.29% of conventional (164/56,552) cases showed AGC+ (p = 0.38). Histology confirmed significant abnormalities in 42 versus 53.5% of the cases, respectively (p = 0.064); 72.7% (SurePath) versus 65.2% (conventional) of these were glandular in nature (p = 0.37). The diagnosis of neoplasia (favored or definitive) showed malignancy on follow-up in 100% of SurePath cases (12/12). In contrast, 82.1% of these conventional cases disclosed premalignant or malignant lesions by histology (p = 0.12). CONCLUSIONS: AGC+ cases showed higher prevalence on SurePath preparations. Conventional cases had more abnormalities on follow-up, while glandular lesions represented a higher proportion of abnormal histologies following SurePath AGC+s. The positive predictive value of favored or definite neoplasia was higher in SurePath cases. Overall, these differences were not statistically significant.

Use of imprint cytology for assessment of surgical margins in lumpectomy specimens of breast cancer patients.

In the past several years, breast-conservation therapy has provided an alternative to mastectomy. In order to reduce the subsequent local tumor recurrence, it is critical that all the measures are in place to find the residual foci of occult microscopic tumor at the time of the initial lumpectomy procedure. An accepted method to evaluate the lumpectomy margins for presence of residual tumor is the use of imprint cytology (also called touch-prep), which is assessment of the presence or absence of the tumor cells by cytological preparation. This is a rapid, cost effective, and easy to use procedure with added advantage of saving tissue for permanent sectioning and rendering a definitive diagnosis. In this report, we present our experience using intraoperative imprint cytology for evaluation of the status of lumpectomy specimens in breast cancer patients. The objective of this study was to evaluate the diagnostic accuracy of intraoperative imprint cytology for assessment of surgical resection margins in lumpectomy margins of patients with breast carcinoma. This is a retrospective study of 100 cases of breast lumpectomy specimens, which had undergone intraoperative imprint cytology. The cases were retrieved from the archived files of the University of Florida, Department of Pathology at Shands Jacksonville. The results of intraoperative imprint cytology were compared with the histological findings of the corresponding permanent sections of the same cases as the gold standard. Overall, we reviewed 510 cytology imprint slides, which were obtained from 100 lumpectomy specimens. Among these cases, 37 slides from 22 cases were reported positive and the remaining were negative. Only eight slides from six cases of lumpectomy showed discrepancy between the result of intraoperative imprint cytology and the permanent sections of the same cases. In our study, intraoperative imprint cytology showed a sensitivity of 97%, specificity of 99%, with positive predictive value of 84%, and negative predictive value of 99%. This study demonstrates that intraoperative imprint cytology can be used as a reliable diagnostic procedure for the evaluation of the status of lumpectomy margins in breast cancer patients.

Diagnostic value of telomerase expression in breast fine-needle aspiration biopsies.

Fine-needle aspiration biopsy (FNAB) of breast is a minimally invasive sampling procedure with a proven value in the initial evaluation of patients with palpable breast lesions. FNAB is a simple, cost-effective, and relatively nontraumatic procedure that has replaced open surgical biopsy in majority of academic institutions across the world. There are, however, inherent limitations in the ability of FNAB to reliably diagnose small percentage of cases that are difficult to diagnose by cytomorphology alone and require excisional biopsy. This shortcoming may be minimized if the morphology can be complemented by a reliable diagnostic adjunct. This retrospective study was designed to assess the added value of telomerase immunostain in interpretation of breast FNABs. Telomerase is a ribonucleoprotein enzyme that has been shown to be activated in different malignant tumors, including breast cancer. Immunocytochemical detection of this molecular marker on cytologic smears and cellblocks may be helpful for interpretation of FNAB specimens. In our retrospective study, we found that 56% of the malignant breast cases (28/50) showed positive telomerase immunostaining while only 4% of the negative cases (2/50) stained with telomerase (positive predictive value: 93%, negative predictive value: 69%). Expression of telomerase on highly suspicious breast fine-needle aspirations may upgrade the diagnosis to malignancy. However, a negative telomerase cannot exclude the possibility of carcinoma.

Endometrial cells on Pap tests: ideal reporting is more complex than just finding the right age.

BACKGROUND: The age for reporting normal endometrial cells (EMCs) on Pap tests was changed to ≥ 45 years in the latest Bethesda update (2014). This recommendation is solely based on age with no consensus on optimal reporting guidelines. METHODS: Pap tests with EMCs for women ≥40 years were retrieved from our Laboratory Information System (LIS). Patient age, last menstrual period (LMP) and available follow-up histology were recorded. Follow-up diagnoses were categorized as: no significant pathology, benign, hyperplasia ± atypia, or malignant. The Fisher's exact test was used to assess the association between categorical variables, p < .05 (two-sided test) was considered significant. RESULTS: Of the 352 cases with EMCs, 155 had surgical follow-up. They showed no malignancy in the 89 women between 40-49 years, compared with five malignancies in the 66 women 50+ years (p = .016). The number of cases with significant pathology (hyperplasia and malignant) was 4 (40-49 years) vs. 11 (50+ years) (p = 0.029). The LMP was inconsistently provided (57%) and women identified as postmenopausal on requisition comprised all the malignancies and half the hyperplasias. CONCLUSION: Combined effort by pathologists and clinicians necessitates determining the best standardized clinicopathologic guidelines to report EMCs and appropriate follow-up. Increasing the required age to ≥50 years would provide more optimal patient management; however, there are other considerations beyond age. Reporting EMCs in postmenopausal women is a reasonable alternative requiring consistent and accurate recording of LMP. Improving provided information for pathologists, determining reporting requirements for EMCs and standardizing clinical follow-up should be a multidisciplinary effort. Diagn. Cytopathol. 2017;45:587-591. © 2017 Wiley Periodicals, Inc.

Effect of aromatic ring-containing drugs on carnitine biosynthesis in rats with special regard to p-aminomethylbenzoic acid.

Secondary carnitine deficiencies are associated with metabolic disorders or may be the consequence of the side effects of some drugs. The mechanisms may be either a facilitated urinary excretion or an inhibited biosynthesis. Based on our earlier findings with drugs and benzoic acid analogue metabolites, in the present study, we studied the possible inhibitory effect of some benzoic acid analogue drugs. In the pathway of carnitine biosynthesis, we tested the last step, the hydroxylation of gamma-butyrobetaine (Bu) to carnitine in the liver. (Liver is the only organ in rats where this step takes place.) Of the 5 tested compounds, the p-aminomethylbenzoic acid (PAMBA) was found to be inhibitory. In tracer experiments with radioactive Bu, PAMBA (a single injection of 1.2 mmol/kg) reduced the conversion of [Me-(3)H]Bu to [Me-(3)H]carnitine from 62.6% +/- 5.11% to 46.8% +/- 5.02% (means +/- SEM, P < .02). This single dose also markedly reduced the conversion of loading amount of exogenous unlabeled Bu, as measured by enzymatic analysis of carnitine. The conversion of endogenous Bu was also hampered by long-term administration of PAMBA, as indicated by increased Bu and decreased carnitine levels. Furthermore, single injection of PAMBA markedly reduced the Glu level in the liver from 2.87 +/- 0.17 to 1.42 +/- 0.11 mumol/g (P < .001). Trying to get closer to a mechanism by which the flux through the Bu hydroxylase was depressed, we supposed that alfa-ketoglutarate (alpha-KG), an obligatory cofactor of the enzyme, was also be depressed. It was expected because alpha-KG is a reversible copartner of l-glutamate through the Glu-dehydrogenase reaction. We found that PAMBA reduced the alpha-KG level from 207 +/- 17.5 to 180 +/- 19.1 nmol/g (means +/- SEM, P < .02). Considering the conditions of the enzyme in vitro and in vivo, this decrease may contribute to the decreased in vivo flux through the butyrobetaine hydroxylase enzyme.