Peptides derived from MARCKS block coagulation complex assembly on phosphatidylserine

Blood coagulation involves activation of platelets and coagulation factors. At the interface of these two processes resides the lipid phosphatidylserine. Activated platelets expose phosphatidylserine on their outer membrane leaflet and activated clotting factors assemble into enzymatically active complexes on the exposed lipid, ultimately leading to the formation of fibrin. Here, we describe how small peptide and peptidomimetic probes derived from the lipid binding domain of the protein myristoylated alanine-rich C-kinase substrate (MARCKS) bind to phosphatidylserine exposed on activated platelets and thereby inhibit fibrin formation. The MARCKS peptides antagonize the binding of factor Xa to phosphatidylserine and inhibit the enzymatic activity of prothrombinase. In whole blood under flow, the MARCKS peptides colocalize with, and inhibit fibrin cross-linking, of adherent platelets. In vivo, we find that the MARCKS peptides circulate to remote injuries and bind to activated platelets in the inner core of developing thrombi.

The ENTPD1 promoter polymorphism -860 A > G (rs3814159) is associated with increased gene transcription, protein expression, CD39/NTPDase1 enzymatic activity, and thromboembolism risk

Ectonucleoside triphosphate diphosphohydrolase 1 (NTPDase1) degrades the purines ATP and ADP that are key regulators of inflammation and clotting. We hypothesized that NTPDase1 polymorphisms exist and that they regulate this pathway. We sequenced the ENTPD1 gene (encoding NTPDase1) in 216 subjects then assessed genotypes in 2 cohorts comprising 2213 humans to identify ENTPD1 polymorphisms associated with venous thromboembolism (VTE). The G allele of the intron 1 polymorphism rs3176891 was more common in VTE vs. controls (odds ratio 1.26-1.9); it did not affect RNA splicing, but it was in strong linkage disequilibrium with the G allele of the promoter polymorphism rs3814159, which increased transcriptional activity by 8-fold. Oligonucleotides containing the G allele of this promoter region bound nuclear extracts more avidly. Carriers of rs3176891 G had endothelial cells with increased NTPDase1 activity and protein expression, and had platelets with enhanced aggregation. Thus, the G allele of rs3176891 marks a haplotype associated with increased clotting and platelet aggregation attributable to a promoter variant associated with increased transcription, expression, and activity of NTPDase1. We term this gain-of-function phenotype observed with rs3814159 G "CD39 Denver."-Maloney, J. P., Branchford, B. R., Brodsky, G. L., Cosmic, M. S., Calabrese, D. W., Aquilante, C. L., Maloney, K. W., Gonzalez, J. R., Zhang, W., Moreau, K. L., Wiggins, K. L., Smith, N. L., Broeckel, U., Di Paola, J. The ENTPD1 promoter polymorphism -860 A > G (rs3814159) is associated with increased gene transcription, protein expression, CD39/NTPDase1 enzymatic activity, and thromboembolism risk.

Spontaneous 8bp Deletion in Nbeal2 Recapitulates the Gray Platelet Syndrome in Mice

During the analysis of a whole genome ENU mutagenesis screen for thrombosis modifiers, a spontaneous 8 base pair (bp) deletion causing a frameshift in exon 27 of the Nbeal2 gene was identified. Though initially considered as a plausible thrombosis modifier, this Nbeal2 mutation failed to suppress the synthetic lethal thrombosis on which the original ENU screen was based. Mutations in NBEAL2 cause Gray Platelet Syndrome (GPS), an autosomal recessive bleeding disorder characterized by macrothrombocytopenia and gray-appearing platelets due to lack of platelet alpha granules. Mice homozygous for the Nbeal2 8 bp deletion (Nbeal2^gps/gps) exhibit a phenotype similar to human GPS, with significantly reduced platelet counts compared to littermate controls (p = 1.63 x 10⁻⁷). Nbeal2^gps/gps mice also have markedly reduced numbers of platelet alpha granules and an increased level of emperipolesis, consistent with previously characterized mice carrying targeted Nbeal2 null alleles. These findings confirm previous reports, provide an additional mouse model for GPS, and highlight the potentially confounding effect of background spontaneous mutation events in well-characterized mouse strains.

A novel mutation in PLP1 causes severe hereditary spastic paraplegia type 2

Hereditary spastic paraplegia (HSP) type 2 is a proteolipid protein (PLP1)-related genetic disorder that is characterized by dysmyelination of the central nervous system resulting primarily in limb spasticity, cognitive impairment, nystagmus, and spastic urinary bladder of varying severity. Previously reported PLP1 mutations include duplications, point mutations, or whole gene deletions with a continuum of phenotypes ranging from severe Pelizaeus-Merzbacher disease (PMD) to uncomplicated HSP type 2. In this manuscript we report a novel PLP1 missense mutation (c.88G>C) in a family from Argentina. This mutation is in a highly conserved transmembrane domain of PLP1 and the mutant protein was found to be retained in the endoplasmic reticulum when expressed in vitro. Due to the variable expressivity that characterizes these disorders our report contributes to the knowledge of genotype-phenotype correlations of PLP1-related disorders.

Constitutive induction of pro-inflammatory and chemotactic cytokines in cystathionine beta-synthase deficient homocystinuria

Cystathionine beta-synthase (CBS) deficient homocystinuria (HCU) is an inherited metabolic defect that if untreated, typically results in cognitive impairment, connective tissue disturbances, atherosclerosis and thromboembolic disease. In recent years, chronic inappropriate expression of the inflammatory response has emerged as a major driving force of both thrombosis and atherosclerotic lesion development. We report here a characterization of the abnormalities in cytokine expression induced in both a mouse model of HCU and human subjects with the disease in the presence and absence of homocysteine lowering therapy. HCU mice exhibited highly significant induction of the pro-inflammatory cytokines Il-1alpha, Il-1beta and TNF-alpha. Similarly, in untreated/poorly compliant human subjects with HCU we observed constitutive induction of multiple pro-inflammatory cytokines (IL-1alpha, IL-6, TNF-alpha, Il-17 and IL-12(p70)) and chemotactic chemokines (fractalkine, MIP-1alpha and MIP-1beta) compared to normal controls. These HCU patients also exhibited significant induction of IL-9, TGF-alpha and G-CSF. The expression levels of anti-inflammatory cytokines were unaffected in both HCU mice and human subjects with the disease. In the human subjects, homocysteine lowering therapy was associated with either normalization or significant reduction of all of the pro-inflammatory cytokines and chemokines investigated. We conclude that HCU is a disease of chronic inflammation and that aberrant cytokine expression has the potential to contribute to multiple aspects of pathogenesis. Our findings indicate that anti-inflammatory strategies could serve as a useful adjuvant therapy for this disease.

A novel transgenic mouse model of CBS-deficient homocystinuria does not incur hepatic steatosis or fibrosis and exhibits a hypercoagulative phenotype that is ameliorated by betaine treatment

Cystathionine beta-synthase (CBS) catalyzes the condensation of homocysteine (Hcy) and serine to cystathionine, which is then hydrolyzed to cysteine by cystathionine gamma-lyase. Inactivation of CBS results in CBS-deficient homocystinuria more commonly referred to as classical homocystinuria, which, if untreated, results in mental retardation, thromboembolic complications, and a range of connective tissue disorders. The molecular mechanisms that underlie the pathology of this disease are poorly understood. We report here the generation of a new mouse model of classical homocystinuria in which the mouse cbs gene is inactivated and that exhibits low-level expression of the human CBS transgene under the control of the human CBS promoter. This mouse model, designated "human only" (HO), exhibits severe elevations in both plasma and tissue levels of Hcy, methionine, S-adenosylmethionine, and S-adenosylhomocysteine and a concomitant decrease in plasma and hepatic levels of cysteine. HO mice exhibit mild hepatopathy but, in contrast to previous models of classical homocystinuria, do not incur hepatic steatosis, fibrosis, or neonatal death with approximately 90% of HO mice living for at least 6months. Tail bleeding determinations indicate that HO mice are in a hypercoagulative state that is significantly ameliorated by betaine treatment in a manner that recapitulates the disease as it occurs in humans. Our findings indicate that this mouse model will be a valuable tool in the study of pathogenesis in classical homocystinuria and the rational design of novel treatments.

The prelamin A pre-peptide induces cardiac and skeletal myoblast differentiation

Prelamin A processing is unique amongst mammalian proteins and results in the production of a farnesylated and carboxymethylated peptide. We examined the effect of pathogenic LMNA mutations on prelamin A processing, and of the covalently modified peptide on cardiac and skeletal myoblast differentiation. Here we report a mutation associated with dilated cardiomyopathy prevents prelamin A peptide production. In addition, topical application of the covalently modified C-terminal peptide to proliferating skeletal and cardiac myoblasts induced myotube and striated tissue formation, respectively. Western blot analysis revealed that skeletal and cardiac myoblasts are the first cell lines examined to contain unprocessed prelamin A, and immunostaining of peptide-treated cells revealed a previously unidentified role for prelamin A in cytoskeleton formation and intercellular organization. These results demonstrate a direct role for prelamin A in myoblast differentiation and indicate the prelamin A peptide may have therapeutic potential.

Natural history of dilated cardiomyopathy due to lamin A/C gene mutations

OBJECTIVES

We examined the prevalence, genotype-phenotype correlation, and natural history of lamin A/C gene (LMNA) mutations in subjects with dilated cardiomyopathy (DCM).

BACKGROUND

Mutations in LMNA have been found in patients with DCM with familial conduction defects and muscular dystrophy, but the clinical spectrum, prognosis, and clinical relevance of laminopathies in DCM are unknown.

BACKGROUND

A cohort of 49 nuclear families, 40 with familial DCM and 9 with sporadic DCM (269 subjects, 105 affected), was screened for mutations in LMNA using denaturing high-performance liquid chromatography and sequence analysis. Bivariate analysis of clinical predictors of LMNA mutation carrier status and Kaplan-Meier survival analysis were performed.

RESULTS

Mutations in LMNA were detected in four families (8%), three with familial (R89L, 959delT, R377H) and one with sporadic DCM (S573L). There was significant phenotypic variability, but the presence of skeletal muscle involvement (p < 0.001), supraventricular arrhythmia (p = 0.003), conduction defects (p = 0.01), and "mildly" DCM (p = 0.006) were predictors of LMNA mutations. The LMNA mutation carriers had a significantly poorer cumulative survival compared with non-carrier DCM patients: event-free survival at the age of 45 years was 31% versus 75% in non-carriers.

CONCLUSIONS

Mutations in LMNA cause a severe and progressive DCM in a relevant proportion of patients. Mutation screening should be considered in patients with DCM, in particular when clinical predictors of LMNA mutation are present, regardless of family history.

Current perspective new insights into the molecular basis of familial dilated cardiomyopathy

Genetic disease transmission has been identified in a significant proportion of patients with dilated cardiomyopathy (DCM). Variable clinical characteristics and patterns of inheritance, as well as recent molecular genetic data, indicate the existence of several genes causing the disease. Several distinct subtypes of familial DCM have been identified. Autosomal dominant DCM is the most frequent form (56% of our cases), and several candidate disease loci have been identified by linkage analysis. Three disease genes are presently known: the cardiac actin gene, the desmin gene, and the lamin A/C gene. This latter gene has recently been found to be responsible for both the autosomal dominant form of DCM with subclinical skeletal muscle disease (7.7% of cases) and the familial form with conduction defects (2.6% of cases) or the autosomal dominant variant of Emery-Dreifuss muscular dystrophy. The autosomal recessive form of DCM accounts for 16% of cases and is characterized by a worse prognosis. An X-linked form of DCM (10% of cases) manifests in the adult population and is due to mutations in the dystrophin gene. In the rare infantile form of DCM, mutations in the G4.5 gene have been identified. Finally, some of the rare unclassifiable forms (7.7% of cases) may be due to mitochondrial DNA mutations. Clinical and experimental evidence based on animal models suggest that, in a large number of cases, DCMs are diseases of the cytoskeleton. However, other causes, such as alterations in regulatory elements and in signaling molecules, are possible. Moreover, other genes called modifier genes can influence the severity, penetrance, and expression of the disease, and they will be a main objective of future investigations. Familial DCM is frequent, cannot be predicted on a clinical or morphological basis and requires family screening for identification. The advances in the genetics of familial DCM can allow improved diagnosis, prevention and genetic counseling, and represent the basis for the development of new therapies.

Lamin A/C gene mutation associated with dilated cardiomyopathy with variable skeletal muscle involvement

BACKGROUND

Dilated cardiomyopathy is a form of heart muscle disease characterized by impaired systolic function and ventricular dilation. Familial transmission of the disease is frequently observed, and genetic heterogeneity is indicated by clinical and morphological variability in the disease phenotype. In the family MDDC1 reported here, the disease phenotype is severe and characterized by an autosomal dominant pattern of transmission. In addition, the majority of affected family members show signs of mild skeletal muscle involvement.

METHODS AND RESULTS

On the basis of the clinical observation of both cardiac and skeletal muscle abnormalities in the MDDC1 family, the lamin A/C gene was examined in this kindred. Coding regions were polymerase chain reaction-amplified from genomic DNA and sequenced. A single nucleotide deletion was identified within exon 6, and all affected individuals were found to be heterozygous for this deletion.

CONCLUSIONS

Heterozygosity for a single nucleotide deletion in exon 6 of lamin A/C segregates with both the cardiac and skeletal abnormalities observed in the MDDC1 family.

Bias in the assessment of family history of melanoma and its association with dysplastic nevi in a case-control study

Family history of melanoma is an important risk factor for both melanoma and, it is thought, dysplastic nevi. However, assessment of family history of melanoma in epidemiologic investigations has typically been limited to interview of the proband. As part of a case-control study of dysplastic nevi, we attempted to confirm family histories. We disproved about half of the reported family histories of melanoma among first-degree relatives, and confirmed them by medical records in only 17%. Few family histories pertaining to other relatives could be confirmed. We documented the association of melanoma family history with dysplastic nevus risk, and we further documented a substantially greater odds ratio for this association when history was based on confirmation by medical records, compared to confirmation by proband interview only. The bias thus documented must be considered in evaluating the many published epidemiologic studies of melanoma and related disorders. Future research should attempt to confirm family histories of melanoma whenever possible, despite the practical difficulties.

Reliability of the histopathologic diagnosis of melanocytic dysplasia. The Dysplastic Nevus Panel

OBJECTIVE

To determine the reliability of the histopathologic diagnosis of melanocytic dysplasia among diverse dermatopathologists who had no joint training, agreed to abide by predetermined criteria, and who were provided reference photomicrographs illustrative of the criteria.

DESIGN, SETTING, AND PARTICIPANTS

A stratified random sample of 112 melanocytic tumors were chosen from the files of the pathology department of a large staff-model health maintenance organization. The original diagnoses included typical and dysplastic melanocytic nevi and melanoma. A single representative slide for each case was interpreted independently by each of the 5 panel dermatopathologists and 2 melanoma specialists. They had no prior knowledge of the original diagnosis or the diagnoses of the other panel members.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Interrater reliability was measured by intraclass and Pearson correlation coefficients. Each case was graded on a 5-point scale from no dysplasia to melanoma.

RESULTS

The intraclass correlation among the panel members was 0.67 (95% confidence interval, 0.59-0.73). The Pearson correlations of each of the 5 panel dermatopathologists with the mean of the 2 melanoma specialists ranged from 0.67 to 0.84, and the correlations of the mean of the panel with the 2 melanoma specialists were 0.79 and 0.82; the mean reading of the melanoma specialists correlated 0.89 with the mean panel reading. Apparent protocol violations occurred in 6.5% of the readings.

CONCLUSIONS

Agreement was substantial to excellent for the histopathologic diagnosis of 112 melanocytic tumors by dermatopathologists. Using predetermined criteria, melanocytic dysplasia can be reproducibly graded among diverse general dermatopathologists.

Multifocal adenocarcinoma in situ with underlying carcinoid tumor of the gallbladder

We describe a case of combined multifocal carcinoma in situ and carcinoid tumor of the gallbladder. Morphologic and immunohistochemical studies revealed two distinct neoplastic patterns without clear evidence of transition between the two processes.

Pathology of bladder carcinoma

Pathologists play an important role in the evaluation of bladder carcinomas. They are responsible for the diagnosis of the tumor and its categorization, grading, and staging, all of which guides urologists and oncologists in subsequent management. There are considerable differences of opinion as to the categorization and grading of papillary neoplasms, which represent the largest subset of bladder biopsy pathologic specimens.

Pathology of testicular germ cell tumors

The pathology report on a testicular germ cell tumor should include the following information: Tumor type: The histologic type of tumor present. If the tumor is of mixed type, the components should be listed, in order of relative abundance. The pathologist may endeavor to give a numeric estimate of the percentages of each element. Staging information: The size of the tumor should be listed. Local spread--into rete testis, tunica albuginea, epididymis, and spermatic cord--should be listed. If the cord is involved, possible involvement of its surgical resection margin should be assessed. Vascular/lymphatic invasion should be assessed for its presence or absence. Status of the remainder of the testis: Evidence of cryptorchidism or other dysgenetic features should be mentioned. Such features may imply a greater risk for the development of a contralateral tumor. Also, the presence of normal spermatogenesis elsewhere in the uninvolved testis should be reported. This finding may suggest a relatively decreased risk for contralateral tumor development and is a likely indicator of fertility should the patient consider sperm banking prior to retroperitoneal surgery and chemotherapy. The finding of mature sperm in the epididymis is an easy way to confirm spermatogenesis in the testis. Incidental findings: Lipomas or hydroceles of the cord, adrenal rests, and adnexal cysts may be found. The pathologist plays a crucial role in the diagnosis of germ cell tumors. In addition to elucidating tumor type, the pathologist is relied upon for precise local staging and for the classification of metastases, all of which have important implications in determining optimal therapy. As the clinical management of germ cell tumors evolves, the pathologist will continue to play a role in defining those features that have a bearing on patient outcome.

Stage I nonseminomatous germ cell testicular tumor: prediction of metastatic potential by primary histopathology

A study of 60 patients with clinical stage I nonseminomatous germ cell testicular tumor (NSGCT) was conducted to identify prognostic factors that may predict the likelihood of metastasis. Clinical features and histopathologic features of the primary testicular tumor were examined and analyzed for correlations with the presence of retroperitoneal nodal metastasis documented by surgery (N+) and with development of relapse (R+). Pathologic tumor stage greater than or equal to 2, with tumor extension into the tunica albuginea, rete testis, epididymis, or spermatic cord, was correlated with an increased rate of N+ compared with pathologic tumor stage I (P = .001). Vascular invasion was correlated with a higher rate of N+ (P = .05) and had a similar association with R+ (P = .08). Tumors containing less than 50% teratoma were found to have a higher rate of N+ than tumors with greater than or equal to 50% teratoma (P = .02). Based on the identified prognostic factors, a model for predicting the probability of retroperitoneal nodal metastasis in clinical stage I patients is proposed. The risk factors for nodal metastasis are: pathologic tumor stage greater than or equal to 2, vascular invasion, and less than 50% teratoma. Patients with none of the risk factors are considered at low risk and may be offered orchiectomy alone with surveillance for initial treatment. Patients with all three risk factors are at high risk and should be treated with a retroperitoneal lymph node dissection (RPLND) or possibly chemotherapy. Patients with one or two risk factors are at intermediate risk; it is recommended that they undergo RPLND. This risk model facilitates a rational approach to the management of clinical stage I NSGCT.

Metal ion blockage of tritium incorporation into gamma-carboxyglutamic acid of prothrombin. Stoichiometry of gamma-carboxyglutamic acid to Gd3+ for the high affinity sites

Prothrombin possesses two high affinity and four low affinity gamma-carboxyglutamic acid (Gla)-dependent gadolinium binding sites. Earlier work (Price, P. A., Williamson, M. K., and Epstein, D. J. (1981) J. Biol. Chem. 256, 1172-1176) has shown that tritium can be specifically incorporated at the gamma-carbon of Gla in proteins at pH 5. In the present work we show that inclusion of saturating concentrations of Ca2+ in nondenaturing buffer systems ranging from pH 5.5 to 8.5 prevents the exchange of tritium into all 10 Gla residues of prothrombin. Similarly, saturating concentrations of Gd3+ prevent tritium incorporation into Gla at pH 5.5. Positive cooperativity was observed for the binding of Gd3+ to human prothrombin (at pH 5.5) for the two high affinity sites (Kd congruent to 35 nM). The four low affinity sites bind Gd3+ with a Kd congruent to 5 microM. Incubation of prothrombin ranging in concentrations from 10 to 40 microM with 2 eq of Gd3+ at pH 5.5 prevents 5.7 (average of seven determinations) Gla residues from tritium incorporation. Sedimentation velocity experiments conducted at pH 5.5 indicate that prothrombin in the presence of saturating concentrations of Gd3+ polymerizes, most likely, to a trimer. Further, in the presence of 2 eq of Gd3+, calculated percent weight average concentration of monomer prothrombin is congruent to 100% at 10 microM, approximately equal to 95% at 20 microM, and congruento to 80% at 40 microM protein concentration. Thus, it appears that under conditions in which prothrombin primarily exists as a monomer, occupancy of the initial two metal binding sites by Gd3+ involves six Gla residues.

Studies of nontraumatic osteonecrosis. The role of core decompression in the treatment of nontraumatic osteonecrosis of the femoral head

This study reports a five-year experience with core decompression for treatment of nontraumatic osteonecrosis of the femoral head. There were 25 patients (39 hips) with predominantly steroid-associated osteonecrosis followed postoperatively for a minimum of two years. All patients were evaluated functionally, roentgenographically, histologically, and hemodynamically. At latest follow-up examination, two of 12 hips (17%) with Stage I disease, seven of 12 hips (58%) with Stage IIA disease, four of four hips with Stage IIB disease, and nine of 11 hips (82%) with Stage III disease have progressed roentgenographically and/or clinically. A lack of correlation between pressure manometrics, venography, and clinical outcome in this study suggests that mechanisms other than progressive ischemia may be involved. Current indications for core decompression are Ficat Stage 0, I, and IIA (sclerotic predominant) disease.

Management of patients with clinical stage I or II nonseminomatous germ cell tumors of the testis. Evolving therapeutic options

Eighty patients with clinical stage I or II nonseminomatous germ cell tumors of the testis were managed with modified protocols, including modified nerve-sparing retroperitoneal lymph node dissection for patients with stage I cancer, retroperitoneal lymph node dissection for patients with low-volume stage II cancer, and initial chemotherapy with or without subsequent retroperitoneal lymphadenectomy for patients with high-volume stage II cancer. Patients with low-stage disease (clinical stage I) were treated successfully with modified retroperitoneal lymph node dissection (relapse rate, three of 40 patients). Clinical understaging was evidenced in 14 of 48 patients with clinical stage I disease who were found to have pathologic involvement of the retroperitoneal lymph nodes, including six patients with extensive retroperitoneal nodal involvement (pathologic stage B2). Of nine patients with retroperitoneal tumors less than 3 cm in diameter, four patients were satisfactorily treated with retroperitoneal lymph node dissection alone while five patients required chemotherapy after retroperitoneal lymph node dissection. Of 26 patients with retroperitoneal tumors 3 to 5 cm in diameter, 17 patients were treated with chemotherapy alone. All patients remain free of disease after the completion of definitive therapy. We conclude that therapeutic options should be modified based on histologic factors in the primary tumor, extent of retroperitoneal disease as indicated on a computed tomographic scan, and presence or absence of elevated tumor markers. By consideration these factors, optimum therapy can be selected to achieve the highest long-term survival rate with the least morbidity.

Studies of nontraumatic osteonecrosis. Manometric and histologic studies of the femoral head after chronic steroid treatment: an experimental study in rabbits

High-dose methylprednisolone was administered to adult rabbits over a five- to nine-week period, according to previously described experimental models of nontraumatic osteonecrosis (NON). Manometric studies were performed using a sensitive computer-directed microvolume flow system. Osteocyte viability within the femoral head was assessed by counting empty osteocyte lacunae in five random high-power fields of hematoxylin- and eosin-stained sections. There was no significant elevation of intramedullary pressure or venous outflow resistance in femoral heads of animals receiving steroids, and a significant random loss of osteocytes was observed in these femoral heads. The clinical relevance of these studies is as follows. NON associated with steroids may not simply be the result of progressive ischemia. Ischemia and elevated intramedullary pressure may be epiphenomena, and a direct cytotoxic effect of steroids on osteocytes may be the earliest event in the development of nontraumatic osteonecrosis. The stress test, as it is currently being used in the clinical setting, may be unreliable.

Adenolymphoma with massive necrosis and squamous metaplasia

A 61-year-old female presented with a longstanding parotid mass with recent change in size. Histologically, the mass was composed of extensively necrotic tissue with a peripheral rim of ribbons of epithelium. In one focus, a double layer of oxyphilic epithelium overlying a lymphoid stroma in a papillary configuration was present, establishing the diagnosis of adenolymphoma (AL). The possibility of infarction and/or infection complicating AL is discussed. In any parotid gland lesion clinically presenting as a longstanding tumor with recent change clinically suggestive of infarction and/or infection, the diagnosis of AL should be considered. In the pathologic specimen with extensive necrosis, areas of preserved epithelium and stroma should be searched for carefully to confirm the diagnosis.

Internal derangements of the temporomandibular joint: diagnosis by direct sagittal computed tomography

The authors performed direct sagittal computed tomography (CT) on 4 cadaver temporomandibular joints (TMJ) and examined 51 TMJs in 47 patients clinically. The results were correlated with cadaver anatomical sections and clinical arthrographic findings. A fat plane between the bellies of the lateral pterygoid muscles, termed the "lateral pterygoid fat pad," served as the anatomical basis for detection of internal derangements by CT. CT was 94% accurate in detecting meniscal derangements and 96% accurate in detecting degenerative arthritis. The authors suggest that CT rather than arthrography be employed as the primary TMJ imaging modality when internal derangement or arthritis is suspected.

An immunohistochemical study of a carcinoma of the parotid gland exhibiting both ductal and acinic cell differentiation

A 76-year-old man underwent a subtotal parotidectomy for removal of a 3 cm. multicystic mass. The tumor was a salivary gland carcinoma, with both infiltrating and intraductal/intra-acinar components, exhibiting three histologic patterns: cribriform, papillary, and comedo-like. Immunohistochemical stain for keratin by the immunoperoxidase technique was strongly reactive in the vast majority of the tumor cells, indicating ductal differentiation of the tumor. Ultrastructural studies indicated primarily ductal differentiation of the tumor cells, with additional areas of acinous and myoepithelial differentiation.