The pathology fellowship application crisis: The current state and suggestions for remediation

Problems within the Pathology fellowship application process in the US have been recognized and reported for years. Recently, members of the Graduate Medical Education Committee (GMEC) of the Association of Pathology Chairs (APC) and collaborators collected survey data from the residents themselves and the fellowship programs, as represented by both the fellowship program directors (members of the Fellowship Directors Ad Hoc Committee, FDAHC) and the program administrators (members of the Graduate Medical Education Administrators Section, GMEAS). These data are presented and discussed, and potential steps to resolve some of the problems around fellowship applications in pathology are presented.

Factors Influencing US Allopathic Medical Students to Choose Pathology as a Specialty

The SARS-CoV-2 pandemic has highlighted the crucial role of pathologists in the health care system at a time of significant decline in the number of US medical students matching to pathology residency positions. To understand this decline, a national survey of fourth-year US allopathic medical students was conducted to assess experiences, knowledge, and attitudes of pathology and factors that impact specialty choice. Participating in a separate pathology course did not increase the probability of choosing pathology. Experiences significantly associated with choosing pathology included clinical or research opportunities in pathology during the last 2 years of medical school, autopsy observation/participation, and participation in pathology interest groups. Many respondents felt they were not sufficiently exposed to pathology to consider it as a specialty. Those who considered pathology but did not choose it were less likely to report understanding the activities of pathologists and being recruited by pathology faculty and more likely to express a preference for more direct patient contact as compared to those entering pathology. In general, respondents agreed that pathology has a good work-life balance and a satisfying degree of intellectual challenge. On the other hand, respondents generally agreed that information on social media and perception of the pathology job market do not seem to be positive and few agreed that pathology is a highly regarded specialty. We identify steps to address these issues and increase the number of US medical students choosing pathology as a specialty crucial to the future of medicine and public health.

Report and Recommendations of the Association of Pathology Chairs' Autopsy Working Group

Autopsy has been a foundation of pathology training for many years, but hospital autopsy rates are notoriously low. At the 2014 meeting of the Association of Pathology Chairs, some pathologists suggested removing autopsy from the training curriculum of pathology residents to provide additional months for training in newer disciplines, such as molecular genetics and informatics. At the same time, the American Board of Pathology received complaints that newly hired pathologists recently certified in anatomic pathology are unable to perform an autopsy when called upon to do so. In response to a call to abolish autopsy from pathology training on the one hand and for more rigorous autopsy training on the other, the Association of Pathology Chairs formed the Autopsy Working Group to examine the role of autopsy in pathology residency training. After 2 years of research and deliberation, the Autopsy Working Group recommends the following:Autopsy should remain a component of anatomic pathology training.A training program must have an autopsy service director with defined responsibilities, including accountability to the program director to record every autopsy performed by every resident.Specific entrustable activities should be defined that a resident must master in order to be deemed competent in autopsy practice, as well as criteria for gaining the trust to perform the tasks without direct supervision.Technical standardization of autopsy performance and reporting must be improved.The current minimum number of 50 autopsies should not be reduced until the changes recommended above have been implemented.

Pediatric Pathology Fellowship Recruitment-Report of a Survey Conducted by the Fellowship Committee of the Society for Pediatric Pathology

Pediatric pathology (PP) is a subspecialty of pathology encompassing disease states during human development from the fetus to the young adult. Despite the existence of ACGME-accredited fellowship programs and opportunity for pediatric pathology subspecialty board certification, many pediatric pathology fellowship positions remain unfilled in North America. We sought to understand the difficulties in recruitment to the PP training programs by conducting a survey. A 3-pronged survey targeting pathology residents (PR), PP fellows and recent fellowship graduates (F&G), and PP training programs was conducted. Three separate questionnaires were prepared, one for each group; and administered online via SurveyMonkey. There were 175 responses to PR survey, 29 to F&G and 19 to programs survey. The results of the PR and F&G survey revealed that trainees select a subspecialty early in their residency training, primarily based on their interest, followed by prospects of employment. Nearly half of resident respondents had discounted pediatric pathology subspecialty training without prior exposure to the specialty. Senior residents and faculty members were reported as the main source for fellowship information for residents choosing subspecialty training and the choice of the training program was mostly dictated by geographic location. Most fellow recruits are racially diverse, female, and American medical graduates. Pathology residents decide on subspecialty training based on their interest; however, many are not exposed to pediatric pathology early on in training. The survey results suggest that existing PP fellowship positions likely will continue to exceed demand for subspecialty training. The results of the study could aid in developing strategies to boost recruitment to PP.

Caffeine consumption does not have an effect on digital microvascular perfusion assessed by laser Doppler imaging on healthy volunteers: a pilot study

Caffeine is one of the most commonly consumed pharmacologically active ingredients in the Western world. It is postulated to cause peripheral vasoconstriction and decreased digital blood flow. As a result, many hand surgeons forbid caffeine consumption post-operatively by patients undergoing replantation surgery for fear of compromising healing. We hypothesized that caffeine has no effect on digital microvascular perfusion. Healthy volunteers were recruited and digital microperfusion was assessed using laser Doppler probes attached to the finger pulp, both before and after ingestion of 100 mg of caffeine. A total of 34 patients were included in the final study. The mean flow before the consumption of caffeine was 226.15 PU. The mean flow following the consumption of caffeine was 197.7 PU. This decrease was not statistically significant. This study revealed no decrease in digital blood flow following the ingestion of 100 mg of caffeine by healthy volunteers, as measured by laser Doppler flow monitoring.

LEVEL OF EVIDENCE

3.

Myelodysplastic syndrome (MDS)-associated cytogenetic abnormalities in pediatric chronic myelogenous leukemia

Chronic myelogenous leukemia (CML) is very rare in the pediatric population. We report the case of a 2-year-old female with CML and concurrent myelodysplastic syndrome (MDS) associated cytogenetic abnormalities. The co-existence of t(9;22) and chromosomal deletions that are associated with MDS poses a unique diagnostic challenge. Given the reported association of t(9;22) and genomic instability, we hypothesize that the chromosomal deletions represent clonal evolution of the CML.

KAI-1 expression in pediatric high-grade osteosarcoma

Recent evidence implicates cell surface proteins of the tetraspanin superfamily in the process of metastasis whereas the downregulation of KAI-1, a member of the tetraspanin family, is associated with an aggressive clinical phenotype in several types of human cancers. To determine if expression of KAI-1-1 is associated with any known prognostic marker or clinical outcome in high-grade osteosarcoma, we examined 91 nondecalcified archival samples from 47 patients for the expression of KAI-1. Archival, paraffin-embedded, and decalcified pathologic samples were examined by immunohistochemistry and results were correlated to clinical outcomes and known prognostic markers. There were 46 samples from diagnostic biopsies (1 diagnostic sample was not available), 32 tumor resection samples, and 13 metastasis samples. Thirty-three percent (n=30) of the samples expressed KAI-1 (16 biopsies, 9 resections, and 5 metastasis). KAI-1 expression was not significantly related to known prognostic markers or to either tumor necrosis after neoadjuvant therapy or the incidence of metastasis at diagnosis. KAI-1 expression was not significantly different between paired diagnostic tumor samples and either resection or metastasis tumor samples. Twenty-five patients remain alive at a median follow-up of 95 months. The overall and progression-free survival percentages at 5 years were 62% and 47% for KAI-1-positive patients and 49% and 38% for KAI-1-negative patients, respectively. This difference was not statistically significant. We conclude that KAI-1 is expressed in a proportion of high-grade osteosarcoma but is not of clinical significance and cannot be used to stratify treatment groups for these patients.

Manganese (IV) oxide-catalyzed electrophilic diamination of electron-deficient alkenes provides an easy synthesis of alpha,beta-diamino acid and ketone derivatives for peptidomimetic studies*

Manganese (IV) oxide was found to catalyze the diamination reaction of alpha,beta-unsaturated esters and ketones with N,N-dichloro-p-toluenesulfonamide and acetonitrile as the halogen and nitrogen sources. The reaction is convenient to be conducted by simply mixing three reactants in the presence of manganese dioxide catalyst and 4 A molecular sieves, and provides an easy access to 1-p-toluenesulfonyl-3-trichloromethyl-4,5-imidazoline derivatives, which are useful building blocks for peptidomimetic studies.

Neonatal lethal osteochondrodysplasia with low serum levels of alkaline phosphatase and osteocalcin

Neonatal lethal skeletal dysplasias are rare and typically involve thoracic malformations and severe limb shortening. We report on a newborn boy manifesting an osteochondrodysplasia associated with fatal respiratory insufficiency who had normal lung volumes and extremity lengths. His disorder featured aberrant skeletal patterning and defective ossification including a severely osteopenic skull, apparent absence of clavicles, and clefting of the mandible and vertebrae. Serum alkaline phosphatase and osteocalcin levels were markedly low. Biochemical studies suggested parathyroid insufficiency probably from critical illness. Histopathology at autopsy excluded impaired mineralization of skeletal matrix, but endochondral bone formation appeared disorganized with growth plate clustering of chondrocytes in hypertrophic zones and in zones of provisional calcification. Parathyroid glands were not found. Despite features of two distinctive heritable entities, hypophosphatasia and cleidocranial dysplasia, the cumulative findings did not match either condition, and no mutations were found in either the tissue nonspecific ALP isoenzyme or core-binding factor genes, respectively, or in the genes encoding osteocalcin or the osteoblast transcription factor osterix. This patient could represent the extreme of cleidocranial dysplasia (a disorder not always associated with structural mutation in core-binding factor A1), but more likely he defines a unique osteochondrodysplasia disrupting both intramembranous and endochondral bone formation.

Pre- and postnatal MR imaging of hypothalamic hamartomas associated with arachnoid cysts

We describe two cases of hypothalamic hamartoma associated with arachnoid cysts. One case was initially documented on prenatal MR images. Because of the rarity of the association and resultant distortion in regional anatomy, the solid component of the mass may be overlooked. This would certainly be true when using lower-resolution diagnostic studies such as fetal MR imaging. The lesion could also be confused with a cystic tumor such as pilocytic astrocytoma. Thorough evaluation is required in patients with precocious puberty, gelastic seizures, and the presence of a suprasellar arachnoid cyst.

Presence of Simian Virus 40 DNA Sequences in Human Lymphoid and Hematopoietic Malignancies and Their Relationship to Aberrant Promoter Methylation of Multiple Genes

The simian polyoma virus SV40 has been detected in specific human tumors including non-Hodgkin's lymphomas, although a causative role for the virus has not been convincingly demonstrated. Aberrant methylation of CpG islands in promoter regions is a frequent method of silencing tumor suppressor genes (TSGs) in cancers and may be induced by oncogenic viruses. We investigated the relationship between the presence of SV40 or EBV DNA sequences and the methylation profiles for 10 TSGs in 90 cases of non-Hodgkin's lymphomas/leukemias and 56 control tissues. SV40 sequences were present in 33/90 (37%) non-Hodgkin's lymphomas/leukemias, and EBV was present in 11/42 (26%) of non-Hodgkin's lymphomas. We found a highly significant correlation between the presence of SV40 and methylation of seven genes (P values, 0.006 to <0.0001). In lymphomas, there was no relationship between EBV and methylation. Oncogenic viruses and methylation were rarely present in control tissues. We investigated methylation of the same 10 TSGs in peripheral blood mononuclear cells (PBMC) from a healthy volunteer infected with EBV or EBV and SV40. Promoter methylation of CDH1 and CDH13 were noted in dual SV40- and EBV-infected PBMC, and these two genes were also highly significantly correlated to the presence of SV40 sequences in tumors. SV40 infection also resulted in appearance of the lymphoma/leukemia-specific marker, methylated SHP1. Methylation was completely absent in uninfected and EBV-infected PBMC. Our results demonstrate that the presence of SV40 in hematological malignancies is associated with promoter methylation of TSGs and that in all probability, the virus plays a role in tumor pathogenesis.

DNA Methylation Profiles of Lymphoid and Hematopoietic Malignancies

PURPOSE

Aberrant methylation of the 5' gene promoter regions is an epigenetic phenomenon that is the major mechanism for silencing of tumor suppressor genes in many cancer types. The aims of our study were (a) to compare the methylation profiles of the major forms of hematological malignancies and (b) to determine the methylation profile of monoclonal gammopathy of undetermined significance (MGUS) and compare it with that of multiple myeloma (MM).

EXPERIMENTAL DESIGN

We compared the aberrant promoter methylation profile of 14 known or suspected tumor suppressor genes in leukemias (n = 48), lymphomas (n = 42), and MMs (n = 40). We also examined the methylation profile of MGUS (n = 20), a premalignant plasma cell dyscrasia. The genes studied represent five of the six "hallmarks of cancer."

RESULTS

Peripheral blood lymphocytes (n = 14) from healthy volunteers were negative for methylation of all genes, and methylation percentages in 41 nonmalignant tissues (peripheral blood mononuclear cells, bone marrows, and lymph nodes) from hematological patients were low (0-9%) for all 14 genes, confirming that methylation was tumor specific. Ten of the genes were methylated at frequencies of 29-68% in one or more tumor types, and the methylation indices (an indicator of overall methylation) varied from 0.25 to 0.34. With two exceptions, the methylation patterns of leukemias and lymphomas were similar. However, the pattern of MMs varied from the other tumor types for six genes. In general, the methylation pattern of MGUS was similar to that of MM, although the methylation frequencies were lower (the methylation index of MGUS was 0.15, and that of MM was 0.3). However, the methylation frequencies of six genes were significantly higher in MGUS than in control tissues. The relatively high frequencies of methylation in MGUS are consistent with it being a premalignant condition.

CONCLUSIONS

The three major forms of lymphoid/hematopoietic malignancies show overlapping but individual patterns of methylation.

Cyclooxygenase-2 expression does not correlate with outcome in osteosarcoma or rhabdomyosarcoma

PURPOSE

To determine if expression of cyclooxygenase (COX)-2, an inducible enzyme with known tumor-promoting activity, correlates with outcome in pediatric sarcomas. COX-2 overexpression correlates with more aggressive disease in a variety of adult solid tumors.

METHODS

Archived human osteosarcoma, rhabdomyosarcoma, and Ewing sarcoma tumors were retrospectively evaluated, blinded to outcome, for COX-2 expression by immunohistochemistry and correlated with patient characteristics and survival.

RESULTS

COX-2 expression was detected in 94 of 142 (66%) tumors (osteosarcoma, 66/99 [67%]; rhabdomyosarcoma, 21/35 [60%]; Ewing sarcoma, 7/8 [88%]) and 51 of 85 (60%) diagnostic biopsies (osteosarcoma, 26/45 [58%]; rhabdomyosarcoma, 21/35 [60%]; Ewing sarcoma, 4/5 [80%]). COX-2 expression did not vary with clinicopathologic features and was not predictive of prognosis in these cases.

CONCLUSIONS

This study does not support the use of COX-2 expression as an upfront prognostic variable in patients with osteosarcoma or rhabdomyosarcoma. Results from the small number of patients studied with Ewing sarcoma suggest a similar lack of predictive value for COX-2 expression. However, COX-2 inhibitors are not entirely dependent upon enzyme expression for their antitumor effects; this study does not necessarily preclude the use of COX-2 inhibitors for the treatment of pediatric sarcomas.

PRCC-TFE3 renal carcinomas: morphologic, immunohistochemical, ultrastructural, and molecular analysis of an entity associated with the t(X;1)(p11.2;q21)

The reappraisal of genetically defined subsets of renal tumors can help to highlight the key pathologic features of specific neoplastic entities. We report the morphologic, immunophenotypic, ultrastructural, and molecular features of 11 renal carcinomas bearing a t(X;1)(p11.2;q21) and/or the resulting PRCC-TFE3 gene fusion. The male/female ratio was 4:7. Ten patients were in the age range of 9-29 years and one was 64 years old (mean 21.3 years, median 15 years). The predominant histologic pattern was nested, with islands of tumor cells compartmentalized by thin-walled capillary vasculature. Minor variations on this pattern yielded solid, acinar, alveolar, and tubular architecture. Papillary architecture was seen in nine cases, usually as a minor component. Neoplastic cells were typically characterized by irregularly shaped nuclei with vesicular chromatin and small nucleoli not visible with a 10x objective, and cytoplasm that ranged from clear to densely granular and eosinophilic. Mitoses were extremely rare; 5 were found in 900 high power fields examined from the 11 neoplasms. The most distinctive immunohistochemical feature of these neoplasms was moderate to intense nuclear labeling for TFE3 protein. These tumors were also consistently immunoreactive for the RCC antigen (10 of 11) and CD10 (9 of 9), whereas cytokeratin and epithelial membrane antigen were negative in four cases and were positive focally in the others. Ultrastructurally, all of the six neoplasms examined showed features consistent with conventional-type (clear cell) renal carcinoma, although two demonstrated distinctive intracisternal microtubules. Both tumors tested contained PRCC-TFE3 fusion transcripts. The differential diagnosis includes conventional-type papillary renal cell carcinoma, conventional-type (clear cell) renal carcinoma, and the ASPL-TFE3 renal carcinomas associated with the t(X;17)(p11.2;q25), with the latter two being morphologically the most similar to the t(X;1) renal carcinomas. Aside from their distinctive clinicopathologic features described here, there is experimental evidence suggesting that these tumors may show differential sensitivity to certain chemotherapeutic agents.

Congenital foregut duplication cysts of the anterior tongue

OBJECTIVE

To review our experience with foregut duplication cysts of the anterior tongue, an unusual and rarely encountered mass in this location.

DESIGN

A retrospective review of patients with anterior tongue foregut duplication cysts identified between 1990 and 2000.

SETTING

Academic, tertiary care children's medical center.

PATIENTS

Six pediatric patients (5 boys and 1 girl) ranging in age from birth to 8 months at diagnosis.

INTERVENTION

Three patients underwent preoperative magnetic resonance imaging (MRI). All 6 patients underwent excisional biopsy.

MAIN OUTCOME MEASURES

Clinical description of foregut duplication cysts, ability to make the diagnosis preoperatively, and recurrence rates.

RESULTS

No patient presented with respiratory compromise, despite the large size of the anterior tongue masses (range, 1.5-2.4 cm). An MRI study was performed in 3 patients, all given a presumptive diagnosis of dermoid cyst based on the radiographic findings. No patient was diagnosed correctly prior to surgical excision. All patients underwent surgical excision, and the average time from birth to surgical excision was 11 months (range, 3 days to 3.7 years). Surgical pathologic findings were reported as a foregut duplication cyst (enterocystoma) in all patients, with 3 specimens containing foci of gastric mucosa. No recurrence has occurred at 1-month follow-up.

CONCLUSIONS

Foregut duplication cysts rarely present in the anterior tongue and are easily misdiagnosed preoperatively. An MRI study is helpful in preoperative planning, although all lesions were radiologically indistinguishable from dermoid cysts. These masses may be an underappreciated entity in the differential diagnosis of congenital anterior tongue masses.

Lack of prognostic significance of intratumoral angiogenesis in nonmetastatic osteosarcoma

BACKGROUND

A need exists to stratify patients with nonmetastatic osteosarcoma into risk subcategories to administer risk-adapted therapy. Intratumoral angiogenesis determined at diagnosis may have a prognostic significance in this malignancy.

PATIENTS AND METHODS

The authors performed a retrospective immunohistochemical study on archival pathologic material from patients with nonmetastatic osteosarcoma, excluding patients with purely chondroblastic tumors associated with hypovascularity of the cartilaginous stroma. Representative sections from the diagnostic biopsies were stained with a murine monoclonal antibody directed against CD34, an endothelial cell marker. Two pathologists unaware of the patients' long-term outcome counted microvessels in 10 microscopic fields from the most active areas of neovascularization.

RESULTS

Between March 1988 and December 1996, 15 girls and 14 boys (median age 12.6 y, range 4.3-18.3) were identified. Seven patients had died of metastatic disease at a median of 3.4 years (range 0.8-7.4) after diagnosis; 22 were alive with no evidence of disease at a median follow-up of 6.8 years (range 2.7-11.4). There was no significant difference in the number of microvessels per field (pathologist 1, median 19 vs. 18.5; pathologist 2, median 15 vs. 10) between survivors or patients who died of metastatic disease. The correlation between the measurements of the two pathologists was excellent (correlation coefficient 0.87).

CONCLUSIONS

Intratumoral neovascularization determined at diagnosis does not correlate with long-term outcome in patients with nonmetastatic osteosarcoma. A prospective study is necessary to confirm these results.

The effectiveness of tonsillectomy in diagnosing lymphoproliferative disease in pediatric patients after liver transplantation

OBJECTIVE

To determine the effectiveness of diagnosing forms of lymphoproliferative disease by performing tonsillectomy in pediatric patients who develop symptomatic or asymptomatic tonsillar hypertrophy during immunosuppressive therapy after liver transplantation.

DESIGN

Retrospective chart and pathological review.

SETTING

Urban tertiary referral children's hospital.

MAIN OUTCOME MEASURES

The presence of a pathological stage of lymphoproliferative disease or Epstein-Barr virus (EBV) diagnosed using tonsillar specimens, resulting in a change in therapy.

RESULTS

Of 275 pediatric patients who underwent liver transplantation, 13 had tonsillectomy performed with histopathological review of the tonsillar specimens. The specimens from 5 patients (39%) demonstrated pathological changes thought to be consistent with EBV-related changes or a form of lymphoproliferative disease. Histological changes ranged from tonsillar hyperplasia associated with EBV infection to large cell lymphoma. Immunosuppressive therapy was reduced or discontinued, and antiviral therapy was initiated.

CONCLUSION

Children who have undergone liver transplantation and develop tonsillar hypertrophy should undergo a diagnostic tonsillectomy, regardless of the clinical presentation, to rule out a form of posttransplant lymphoproliferative disease. Arch Otolaryngol Head Neck Surg. 2000;126:1444-1447

Self-inflicted wounds, template-directed gap repair and a recombination hotspot. Effects of the mariner transposase

Aberrant repair products of mariner transposition occur at a frequency of approximately 1/500 per target element per generation. Among 100 such mutations in the nonautonomous element peach, most had aberrations in the 5' end of peach (40 alleles), in the 3' end of peach (11 alleles), or a deletion of peach with or without deletion of flanking genomic DNA (29 alleles). Most mariner mutations can be explained by exonuclease "nibble" and host-mediated repair of the double-stranded gap created by the transposase, in contrast to analogous mutations in the P element. In mariner, mutations in the 5' inverted repeat are smaller and more frequent than those in the 3' inverted repeat, but secondary mutations in target elements with a 5' lesion usually had 3' lesions resembling those normally found at the 5' end. We suggest that the mariner transposase distinguishes between the 5' and 3' ends of the element, and that the 5' end is relatively more protected after strand scission. We also find: (1) that homolog-dependent gap repair is a frequent accompaniment to mariner excision, estimated as 30% of all excision events; and (2) that mariner is a hotspot of recombination in Drosophila females, but only in the presence of functional transposase.

Craniopagus parasiticus: a case illustrating its relationship to craniopagus conjoined twinning

A case of craniopagus parasiticus is described in which the parasitic twin is more fully developed anatomically than in any of the previous reports. Somatic and placental vascular anastomoses between the twins and hypoplasia of the umbilical cord of the parasite were also observed. These findings support the hypothesis that craniopagus parasiticus results from compromise of the blood supply to one of a pair of craniopagus conjoined twins.

Protease-activated receptor 3 is a second thrombin receptor in humans

Thrombin is a coagulation protease that activates platelets, leukocytes, endothelial and mesenchymal cells at sites of vascular injury, acting partly through an unusual proteolytically activated G-protein-coupled receptor. Knockout of the gene encoding this receptor provided definitive evidence for a second thrombin receptor in mouse platelets and for tissue-specific roles for different thrombin receptors. We now report the cloning and characterization of a new human thrombin receptor, designated protease-activated receptor 3 (PAR3). PAR3 can mediate thrombin-triggered phosphoinositide hydrolysis and is expressed in a variety of tissues, including human bone marrow and mouse megakaryocytes, making it a candidate for the sought-after second platelet thrombin receptor. PAR3 provides a new tool for understanding thrombin signalling and a possible target for therapeutics designed selectively to block thrombotic, inflammatory and proliferative responses to thrombin.

MURCS association: ultrasonographic findings and pathologic correlation

MURCS association is a rare, lethal and unusual constellation of nonrandom findings that includes mullerian duct aplasia, renal aplasia, and cervicothoracic somite dysplasia.1-3 It has been described in 30 patients by Duncan and coworkers2 in 1979, in which report the authors proposed an embryologic cause for these defects.3 Antenatal ultrasonographic findings included a massive, cystic umbilical cord related to a patent urachus, enlarged bladder, single small kidney, and suspicion of urethral obstruction in a fetus of female phenotype. These findings are rare in a case of MURCS and were all confirmed on pathologic examination.

Reversible idiopathic acute renal failure in children with primary nephrotic syndrome

We describe the clinical features of four pediatric patients (20 months to 10 years of age) in whom reversible idiopathic acute renal failure (RIARF) developed during the course of primary nephrotic syndrome (PNS). All patients had severe PNS and were in relapse at the onset of RIARF. This complication of PNS was preceded by primary peritonitis in three of four patients. Renal biopsy done in the early phases of RIARF showed tubular epithelial changes similar to those observed in acute tubular ischemia. All patients required dialysis. Recovery of renal function followed fluid removal in three of four patients. The RIARF lasted from 12 days to 1 year and was followed by complete recovery of renal function in all patients. We conclude that (1) RIARF is a potential complication in children with severe PNS, (2) RIARF is associated with primary ischemic renal tubular injury, and (3) recognition of the reversibility of this complication of PNS could alter long-term plans for management of renal failure in these patients.

Intracellular distribution of cystine in cystine-loaded proximal tubules

Cellular cystine loading with cystine dimethyl ester has been shown to inhibit transport in proximal convoluted tubules perfused in vitro and decrease the rate of oxygen consumption in suspensions of proximal tubules. The present study was designed to examine the intracellular distribution of cystine in this model of the Fanconi syndrome of cystinosis and to determine whether cystine or its degradation product, cysteine, is the cytotoxic agent in cystine-loaded rabbit proximal tubules. Tubules were incubated with 2 mmol/L cystine dimethyl ester for 10 min at 37 degrees C and subjected to cellular fractionation. The intralysosomal cystine content (272 +/- 125 nmol/mg protein) was significantly higher than that measured in the nucleus (8.7 +/- 2.0 nmol/mg protein) and cytosol (9.8 +/- 4.0 nmol/mg protein (p < 0.05). Electron micrographs of tubules loaded with cystine depicted large swollen lysosomes. To determine whether cystine or its breakdown product, cysteine, was the cytotoxic agent in tubules incubated with cystine dimethyl ester, the intracellular cystine and cysteine contents were measured and found to be 86.5 +/- 14.8 and 5.7 +/- 1.7 nmol/mg protein, respectively. These tubules had a 50% decrease in the rate of O2 consumption. To examine whether the increased level of intracellular cysteine played a role in this decrease in O2 consumption, we loaded tubules with 2 mmol/L cysteine methyl ester for 10 min. Despite an intracellular cysteine concentration of 59.6 +/- 5.8 nmol/mg protein, cysteine-loaded tubules had a rate of O2 consumption equal to that measured in control tubules. Thus, intracellular cystine loading significantly increases intralysosomal cystine content.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular and cellular heterogeneity of Wilms' tumor

We developed a Wilms' tumor-cell culture system to investigate the molecular basis of nephrogenesis and oncogenesis. Several distinct fractions of cells were isolated and characterized from the same tumor specimen. The cells exhibited striking differences in morphology, immunocytochemical staining profiles and cytogenetics. One fraction contained cells with features of epithelium; other cell fractions resembled partially differentiated mesenchyme (blastema or stroma). While the Wilms' tumor-suppressor gene WT1 was not altered, loss of heterozygosity (LOH) and an insertion in intron I of the p53 tumor-suppressor gene occurred in the tumor and the cultured cell types. LOH for RB was detected only in the cultured cells. These findings are consistent with a model of tumor initiation in a pluripotent cell that is able to undergo subsequent differentiation along multiple different lines and which mimics normal nephrogenesis.

Hepatic artery thrombosis in children with liver transplants: false-positive findings at Doppler sonography and arteriography in four patients

OBJECTIVE

Patency of the hepatic artery in patients with liver transplants is evaluated with duplex Doppler sonography. In many centers, loss of an arterial waveform in the liver hilum is an indication for immediate arteriography to confirm the presence of hepatic artery thrombosis. We describe the findings in four children with liver transplants in whom occlusion of the graft artery was erroneously suggested by findings on duplex Doppler sonography and angiography.

MATERIALS AND METHODS

We describe four patients 14-26 months old who had undergone liver transplant 9 days to 9 weeks earlier. The patients were critically ill with sepsis and hypotension. Duplex Doppler sonography was performed by interrogation of the hepatic artery in the liver hilum and parenchyma. When loss of an arterial waveform in the hilum was identified, angiography was performed immediately. Angiography consisted of aortography in all patients and selective celiac or superior mesenteric angiography in three patients. Autopsy was performed in all patients.

RESULTS

Duplex Doppler sonography showed loss of arterial waveforms in the liver hilum in all patients; intrahepatic arterial waveforms were absent in three. The hepatic artery was not opacified at arteriography, but all patients had a patent hepatic artery at autopsy. Postmortem hepatic histology showed massive hepatic necrosis in three patients--necrosis without rejection in two and necrotizing vasculitis associated with severe rejection in one. The fourth patient had minor hepatic parenchymal injury.

CONCLUSION

We conclude that failure to show flow in the hepatic artery with duplex Doppler sonography and arteriography is not necessarily indicative of arterial thrombosis. A low-flow nonocclusive phenomenon caused by massive hepatic necrosis or systemic hypotension may not be distinguishable from arterial occlusion.

Chromosomal abnormalities associated with congenital contractures (arthrogryposis)

In a study of 350 patients with multiple congenital contractures (arthrogryposis), 80 (23%) patients had mental retardation or were developmentally delayed. Out of that group of 80 patients, 13 (16%) were found to have abnormal karyotypes. Two of the thirteen had a family history of chromosomal abnormalities without congenital contractures, therefore, 11 patients had chromosomal anomalies which appeared to be associated with the congenital contractures. Five of the eleven (45%) had chromosome mosaicism, three of those had tissue mosaicism. Two had abnormal skin fibroblast cell lines and normal peripheral leukocyte chromosome studies and one had a normal bone marrow karyotype with abnormal peripheral leukocyte chromosome studies. Chromosome studies were done in these patients with congenital contractures because of developmental delay and multisystem involvement, or recognition of clinical features typical of a chromosomal syndrome. We recommend first lymphocyte; and if those are normal, then fibroblast studies be done on all patients with multiple joint contractures and developmental delay, particularly if unusual facial features or multisystem abnormalities are present.