Malignant female genital tract smooth muscle tumors with adipocytic differentiation: A morphologic, immunohistochemical, MDM2 fluorescence in situ hybridization and molecular genetic study of 6 lipoleiomyosarcomas

Leiomyosarcoma with adipocytic differentiation or lipoleiomyosarcoma is an uncommon sarcoma of the female genital tract with only a few individual reports in the literature. We therefore performed a morphologic, immunohistochemical, MDM2 gene amplification and RNA and DNA sequencing analysis of a series of gynecologic lipoleiomyosarcoma to better define the clinicopathologic spectrum. Six tumors from 6 patients were identified and classified as spindled lipoleiomyosarcoma (n = 2), mixed spindled and myxoid lipoleiomyosarcoma (n = 1), epithelioid lipoleiomyosarcoma with focal myxoid features (n = 1) and mixed spindled and epithelioid lipoleiomyosarcoma (n = 2). Patient age ranged from 41 to 64 years (mean: 49; median: 50). Primary location included uterine corpus (3), uterine corpus/cervix (2) and broad ligament (1). Tumor size ranged from 4.5 to 22 cm (mean: 11.2; median: 9.8). Four patients had metastasis at presentation or subsequently developed recurrent or distant disease. Patient status was known for 5: 2 dead of disease, 2 alive with disease and 1 alive without evidence of disease. Immunohistochemical expression of smooth muscle markers, ER, PR and WT-1 showed patterns similar to non-adipocytic gynecologic leiomyosarcomas. MDM2 amplification fluorescence in situ hybridization performed on 2 tumors was negative in 1 and equivocal in 1. Sequencing studies performed on 3 tumors found TP53 mutations in 3, with 1 tumor also having an ATRX alteration. No gene fusions were identified. Although lipoleiomyosarcomas have a diverse morphologic spectrum, our findings suggest the smooth muscle component shares morphologic and immunohistochemical features with female genital tract non-adipocytic leiomyosarcomas. Lipoleiomyosarcomas also have genetic alterations associated with non-adipocytic gynecologic leiomyosarcomas.

Stable thyroid cancer in a patient with thoracic aortic aneurysm and MYH11 variation

Summary

We report the case of a male patient with papillary thyroid cancer, familial thoracic aortic aneurysm and dissection, and a variation in the MYH11 gene. Because of considerable tumor bulk in the neck that was not resectable, the patient underwent partial resection at age 14 years. Since then, the patient has received only suppressive thyroid hormone therapy. He is now 71 years old, which is 57 years after the initial resection. The patient received care at our institution from July 2009 to August 2019, during which we documented the stability of multiple calcified masses in the neck. Follow-up examinations at another institution from September 2019 to April 2023 also confirmed the stability of the masses. The underlying cause of this unusually long indolent course of the disease is unclear. Whether extensive tumor calcifications or the MYH11 sequence variation contributed to the disease course is also uncertain.

Learning points

Papillary thyroid cancer with neck metastases may, in some cases, be stable and remain asymptomatic for decades. If locoregional stability of papillary thyroid cancer is documented for many years, observation may be preferable to extensive neck surgery in selected cases. This is the first report of an MYH11 gene alteration and thoracic aortic aneurysm in a patient with papillary thyroid cancer with indolent neck metastases. Future studies of MYH11 gene alterations in thyroid carcinoma are needed.

The evolution of cervical cancer screening

There are few medical success stories in history as significant as the reduction in cervical cancer incidence. Through the collaborative efforts of dedicated scientific pioneers, the past century has witnessed remarkable advancement that began with the detection of exfoliated cancer cells through cytologic examination to widespread implementation of cervical cancer screening programs to the discovery of the link between cervical cancer and human papillomavirus (HPV). Current screening methods apply HPV-based testing, and artificial intelligence-based screening systems utilizing digitalized cytology images are being used in a continuous effort to optimize the accuracy and efficiency of the Papanicolaou test. This review summarizes the major milestones in cervical cancer screening history to emphasize its evolution as the World Health Organization aims for the global elimination of cervical cancer.

Benign female genital tract smooth muscle tumors with adipocytic differentiation: A morphologic, immunohistochemical and MDM2 fluorescence in situ hybridization study of 44 conventional lipoleiomyomas and lipoleiomyoma variants

Leiomyomas with adipocytic differentiation typically occur in the uterus although they may arise at several sites in the female genital tract. While these are most commonly spindled leiomyomas with a component of adipocytic tissue ("conventional lipoleiomyomas"), there is a relatively ill-defined assortment of leiomyoma variants with adipocytic differentiation. We performed a morphologic, immunohistochemical and MDM2 gene amplification analysis of a large series of gynecologic leiomyomas with adipocytic differentiation to better define the clinicopathologic spectrum. Forty four tumors from 44 patients were identified and classified as conventional lipoleiomyoma (n = 21), adipocyte-rich lipoleiomyoma (defined as tumor volume >80 % adipocytes, n = 9); cellular lipoleiomyoma (n = 9); hydropic lipoleiomyoma (n = 3); and lipoleiomyoma with bizarre nuclei (n = 2). Patient age ranged from 32 to 83 years (mean 63; median 63). Primary location included uterine corpus (35), uterine cervix (3), uterine corpus/cervix (1), broad ligament (2), parametrium (2), and round ligament (1). Tumor size was 0.6-30 cm (mean 8; median 6). None of the 34 patients with follow up developed further disease (range 1-311 months; mean 65; median 41). Immunohistochemical expression of ER, PR, HMB45, Melan A, Cathepsin K and WT-1 in lipoleiomyomas and variants was similar to patterns in non-adipocytic gynecologic leiomyomas. MDM2 amplification fluorescence in situ hybridization performed on 14 tumors was negative in all. Our findings suggest female genital tract conventional lipoleiomyomas and lipoleiomyoma variants largely parallel their non-adipocytic counterparts in morphology and immunophenotype, and may be categorized using non-adipocytic leiomyoma histologic criteria.

Lipoblastoma-Like Tumor and Fibrosarcoma-Like Lipomatous Neoplasm Represent the Same Entity: A Clinicopathologic and Molecular Genetic Study of 23 Cases Occurring in Both Men and Women at Diverse Locations

Lipoblastoma-like tumor (LLT) is a benign soft tissue tumor demonstrating mixed morphologic features of lipoblastoma, myxoid liposarcoma, and spindle cell lipoma but lacking genetic alterations associated with those tumors. LLT was originally thought to be specific to the vulva but has since been reported in the paratesticular region. The morphologic features of LLT overlap with those of "fibrosarcoma-like lipomatous neoplasm" (FLLN), a rare, indolent adipocytic neoplasm considered by some to form part of the spectrum of atypical spindle cell and pleomorphic lipomatous tumor. We compared the morphologic, immunohistochemical, and genetic features of 23 tumors previously classified as LLT (n = 17) and FLLN (n = 6). The 23 tumors occurred in 13 women and 10 men (mean age, 42 years; range, 17 to 80 years). Eighteen (78%) cases arose in the inguinogenital region, whereas 5 tumors (22%) involved noninguinogenital soft tissue, including the flank (n = 1), shoulder (n = 1), foot (n = 1), forearm (n = 1), and chest wall (n = 1). Microscopically, the tumors were lobulated and septated, with variably collagenized fibromyxoid stroma, prominent thin-walled vessels, scattered univacuolated or bivacuolated lipoblasts, and a minor component of mature adipose tissue. Using immunohistochemistry, 5 tumors (42%) showed complete RB1 loss, with partial loss in 7 cases (58%). RNA sequencing, chromosomal microarray, and DNA next-generation sequencing study results were negative for significant alterations. There were no clinical, morphologic, immunohistochemical, or molecular genetic differences between cases previously classified as LLT or FLLN. Clinical follow-up (11 patients [48%]; range, 2-276 months; mean, 48.2 months) showed all patients were alive without disease, and only one patient had experienced a single local recurrence. We conclude that LLT and FLLN represent the same entity, for which "LLT" seems most appropriate. LLT may occur in either sex and any superficial soft tissue location. Careful morphologic study and appropriate ancillary testing should allow for the distinction of LLT from its potential mimics.

Invasive urothelial carcinoma with squamous differentiation and associated high-risk human papilloma virus infection: Clinical, cytologic, and histologic features of a rare entity

We correlate the fine needle aspiration (FNA) cytologic findings with the histologic features of an invasive high-grade urothelial carcinoma showing squamous differentiation in the setting of high-risk Human Papilloma Virus (hrHPV) infection. To our knowledge, only extensive urinary bladder catheterization has been associated with hrHPV-positive urothelial carcinoma with squamous differentiation, and rarely at that. Herein, we present a case arising in a patient with only sparse and intermittent catheterization. A 69-year-old woman presented with voiding difficulties, and after continued symptoms, a Foley catheter was placed, and a cystoscopy procedure revealed two 1-2 cm inflammatory masses. Excisional biopsies were interpreted as papillary urothelial carcinoma. One month follow-up pelvic imaging demonstrated a new mass involving the urinary bladder neck, with irregular wall thickening and perivesical fat stranding, as well as probable vaginal involvement. CT-guided FNA (CT-FNA) to collect smears and core biopsies revealed an invasive urothelial carcinoma with squamous differentiation. HPV-cytopathic changes amid squamous metaplasia and dysplasia were noted on FNA smears with HPV E6/E7 RNA in situ hybridization (ISH) showing on the FNA core biopsy specimen. Immunostains showed that the tumor cells were positive for P16 (strong, diffuse), CK7, p63, ER, and GATA3 (patchy). Subsequent radical cystectomy revealed the extent of the patient's carcinoma, with direct extension to the vaginal wall, and involvement of the radial soft tissue resection margins. Describing the cytomorphologic features of a hrHPV positive urothelial carcinoma with squamous differentiation, without an extensive history of urinary catheterization or prior known history of HPV infection, emphasizes the role of cytopathology as a powerful diagnostic tool for recognizing a unique and unexpected lesion.

Lymphangioleiomyomatosis in lymph node cytology: Another "Floating Island" to visit

Lymphangioleiomyomatosis (LAM) is a rare disease with variable presentations. The neoplastic cells in LAM demonstrate a unique and diagnostically important "myomelanocytic" phenotype. Cytologic reports of LAM are infrequent and have not in the past emphasized the floating island pattern in which circumscribed aggregates of lesional cells are rimmed by appliques of flattened endothelium. This case illustrates the cytology of LAM and emphasizes that the floating island cytoarchitectural pattern more classically associated with entities such as hepatocellular carcinomas may be seen in cytological preparations of LAM at unanticipated body sites.

ALK-positive histiocytosis: a new clinicopathologic spectrum highlighting neurologic involvement and responses to ALK inhibition

ALK-positive histiocytosis is a rare subtype of histiocytic neoplasm first described in 2008 in 3 infants with multisystemic disease involving the liver and hematopoietic system. This entity has subsequently been documented in case reports and series to occupy a wider clinicopathologic spectrum with recurrent KIF5B-ALK fusions. The full clinicopathologic and molecular spectra of ALK-positive histiocytosis remain, however, poorly characterized. Here, we describe the largest study of ALK-positive histiocytosis to date, with detailed clinicopathologic data of 39 cases, including 37 cases with confirmed ALK rearrangements. The clinical spectrum comprised distinct clinical phenotypic groups: infants with multisystemic disease with liver and hematopoietic involvement, as originally described (Group 1A: 6/39), other patients with multisystemic disease (Group 1B: 10/39), and patients with single-system disease (Group 2: 23/39). Nineteen patients of the entire cohort (49%) had neurologic involvement (7 and 12 from Groups 1B and 2, respectively). Histology included classic xanthogranuloma features in almost one-third of cases, whereas the majority displayed a more densely cellular, monomorphic appearance without lipidized histiocytes but sometimes more spindled or epithelioid morphology. Neoplastic histiocytes were positive for macrophage markers and often conferred strong expression of phosphorylated extracellular signal-regulated kinase, confirming MAPK pathway activation. KIF5B-ALK fusions were detected in 27 patients, whereas CLTC-ALK, TPM3-ALK, TFG-ALK, EML4-ALK, and DCTN1-ALK fusions were identified in single cases. Robust and durable responses were observed in 11/11 patients treated with ALK inhibition, 10 with neurologic involvement. This study presents the existing clinicopathologic and molecular landscape of ALK-positive histiocytosis and provides guidance for the clinical management of this emerging histiocytic entity.

Evaluation of high-risk human papillomavirus testing and anal cytology to detect high-grade anal intraepithelial neoplasia

INTRODUCTION

Optimal screening for detection of anal precancer has not been established, and most studies involve very high-risk populations. We evaluated high-risk human papillomavirus (HPV) testing and anal cytology to detect high-grade anal intraepithelial neoplasia (≥AIN2) in a cohort with mostly moderate risk factors for AIN.

METHODS

Patients ≥35 years old undergoing anal biopsy for various lesions received HPV testing by Roche cobas and a subset by Hologic APTIMA HPV assays with concurrent anal ThinPrep cytology. Biopsies were blindly reviewed by 3 authors, and consensus diagnosis was compared with HPV and cytology results. Sensitivity and specificity for ≥AIN2 detection by HPV testing and cytology (≥ASC-US) were calculated.

RESULTS

Among 64 patients, 19 (29.7%) showed ≥AIN2 on biopsy. All patients were tested by cobas, and 35 (54.7%) were positive. A subset of 39 patients were also tested by APTIMA, and 18 (46.2%) were positive. Positive cytology (≥ASC-US) was present in 37 (57.8%) patients, with 27 (73.0%) of these positive by cobas. HPV testing alone yielded 75.0% and 84.2% sensitivity for APTIMA and cobas, respectively; specificity was 66.7% and 57.8%. Sensitivity and specificity of cytology alone was 78.9% and 51.1%. Combined HPV testing and cytology had a sensitivity and specificity of 91.7% and 37.0% for APTIMA and 94.7% and 40.0% for cobas.

CONCLUSIONS

Combined HPV testing and cytology had the highest sensitivity for ≥AIN2 detection, with a performance comparable to cervical cancer screening tests, suggesting this strategy may represent a viable screening option in a population with moderate risk factors for AIN.

Clinical, biological, radiological, and pathological comparison of sparsely and densely granulated somatotroph adenomas: a single center experience from a cohort of 131 patients with acromegaly

PURPOSE

Growth hormone-producing pituitary adenomas are divided into two clinically relevant histologic subtypes, densely (DG-A) and sparsely (SG-A) granulated. Histologic subtype was evaluated in a large cohort of patients with acromegaly, separating DG-A and SG-A, and correlated with clinicopathological characteristics.

METHODS

Patients with acromegaly undergoing surgery as initial therapy between 1995 and 2015 were identified. Histologic subtype was determined by keratin expression pattern with CAM5.2 and correlated with clinical and imaging parameters, somatostatin receptor subtype 2 (SST2) expression, post-surgical remission rate, and application of a prognostic scoring system incorporating proliferation and invasiveness.

RESULTS

One hundred thirty-one patients were included. Tumors were classified as DG-A (75, 57.3%), SG-A (29, 22.1%), intermediate (I-A) (9, 6.9%), and unclassified (18, 13.7%) when CAM5.2 was negative. DG-A and I-A were combined for analysis (DG/I-A) and compared to SG-A. Age, gender, proliferation, and post-surgical remission did not differ. SG-A were larger [2 vs. 1.5 cm (median), p = 0.03], more frequently invasive [65.5% vs. 32.9%, p = 0.004], associated with higher MRI T2-weighted signal ratio [1.01 vs. 0.82 (median), p = 0.01], showed lower SST2 expression (p < 0.0001), and scored higher in the prognostic classification (p = 0.004). Surgical remission occurred in 41.7% DG/I-A and 41.4% SG-A (p = 1.0). On multivariate analysis, absence of invasion (p = 0.009) and lower pre-operative IGF-1 index (p = 0.0002) were associated with post-surgical remission.

CONCLUSION

CAM5.2 allowed distinction between DG/I-A and SG-A in most but not all cases. Histologic subtype did not predict surgical outcome. Absence of invasion and lower pre-operative IGF-1 index were the only significant predictors of post-surgical remission in this cohort.

A Comprehensive Study of Spindle Cell Oncocytoma of the Pituitary Gland: Series of 6 Cases and Meta-Analysis of 85 Cases

OBJECTIVE

To discuss optimal treatment strategy for spindle cell oncocytoma (SCO) of the pituitary gland.

METHODS

Institutional cases were retrospectively reviewed. A systematic literature search and subsequent quantitative synthesis were performed for further analysis. The detailed features were summarized and the tumor control rate (TCR) was calculated.

RESULTS

Eighty-five patients (6 institutional and 79 literature) were included. The annual incidence was approximately 0.01-0.03/100,000. The mean age was 56 years. Vision loss was present in 60%. Seventy-three percent showed hormonal abnormalities. On magnetic resonance imaging, tumor was avidly enhancing, and the normal gland was commonly displaced anterosuperiorly. Evidence of hypervascularity was seen in 77%. Gross total resection (GTR) was achieved in only 24% because of its hypervascular, fibrous, and adhesive nature. The mean postoperative follow-up was 3.3 years for institutional cases and 2.3 years for the integrated cohort. The TCR was significantly better after GTR (5-year TCR, 75%; P = 0.012) and marginally better after non-GTR + upfront radiotherapy (5-year TCR, 76%; P = 0.103) than after non-GTR alone (5-year TCR, 24%). The TCRs for those with low Ki-67 index (≤5%) were marginally better than those with higher Ki-67 index (5-year rate, 57% vs. 23%; P = 0.110).

CONCLUSIONS

Frequent endocrine-related symptoms, hypervascular signs, and anterosuperior displacement of the gland support preoperative diagnosis of SCO. GTR seems to have better long-term tumor control, whereas the fibrous, hypervascular, and adhesive nature of SCO makes it difficult to achieve GTR. In patients with non-GTR, radiotherapy may help decrease tumor progression.

Spinal Cord Ependymomas With MYCN Amplification Show Aggressive Clinical Behavior

Adult spinal cord ependymomas are typically low grade and have a relatively favorable clinical course following gross total resection. We report 4 cases of anaplastic spinal cord ependymoma with MYCN amplification, an exceptionally rare finding. All cases occurred in the spinal cord of adolescent and young adult women and had morphological and immunohistochemical features of anaplastic ependymomas (World Health Organization grade III). Chromosomal microarray analysis demonstrated amplification of 2p24 (including MYCN) in all cases. One patient died 6 months after surgery. Another patient recently had removal of metastatic nodules in the thoracic region, following gross total resection and adjuvant radiation therapy of a lumbar ependymoma 1 year previously. One patient responded well after chemotherapy but died after multiple relapses 82 months after diagnosis. We found MYCN amplification reported in 2 other ependymomas, both anaplastic and arising in the spinal cord of adult females (Brain Pathol 2001;11:133-43). One patient had multiple recurrences in the spinal cord and an intracranial metastasis. Although MYCN amplification is rare in ependymomas, the current and previously reported cases suggest that this is associated with higher-grade histology, spinal location, and often unfavorable prognosis. The clinical significance and therapeutic implications of MYCN amplification in ependymomas require further evaluation.

Incidence of succinate dehydrogenase and fumarate hydratase-deficient renal cell carcinoma based on immunohistochemical screening with SDHA/SDHB and FH/2SC

Mutations of the succinate dehydrogenase (SDHX) enzyme subunits commonly lead to a loss of function of the holoenzyme complex, and germline SDHX mutations lead to a genetic predisposition to SDH-deficient neoplasms, including renal cell carcinomas (RCC). Similarly, loss-of-function alterations of fumarate hydratase (FH) leads to a genetic predisposition to hereditary leiomyomatosis and renal cell cancer (HLRCC)-associated RCC. Loss of FH leads to an accumulation of fumarate and aberrantly high levels of S-(2-succino)-cysteine (2SC). Subtype-specific consecutively diagnosed renal cell neoplasms were selected for the study and cases were not otherwise selected based on clinicopathologic features. Tissue microarrays were constructed from 1009 renal cell neoplasms (papillary: 400, clear cell: 203, chromophobe: 87, oncocytomas [original diagnosis]: 273, unclassified: 46) and these cases were immunostained for SDHA/SDHB to screen for SDH loss. A smaller subset (n = 730; oncocytomas, papillary and unclassified RCCs) were screened for FH-deficiency using immunohistochemistry for FH/2SC. Loss of SDHA/SDHB was seen in three of 273 tumors originally diagnosed as oncocytomas (1.1%). Diffuse nuclear and cytoplasmic 2SC staining, with retained FH expression was seen in one case (suggestive of dysfunctional FH protein), while absent FH was seen in 3 cases (2/400 papillary RCCs, 0.5% and 2/46 unclassified RCCs, 4.35%). No aberrant FH/2SC expression was noted in 273 cases originally diagnosed as oncocytomas. SDH-deficient RCCs were identified only in the cases originally diagnosed as oncocytomas (1.1%), while FH-deficient RCCs were identified in the papillary (0.5%) and unclassified RCC cohorts (4.35%). These results can help guide immunohistochemistry-based screening strategies for these tumors.

Low-grade fibromyxoid sarcoma arising within the median nerve

We report a case of low-grade fibromyxoid sarcoma arising within the median nerve. A 31-year-old woman presented with symptoms of carpal tunnel syndrome and an enlarging mass in her right palm over 1 year. MRI demonstrated a mass associated with the right median nerve with solid and cystic components. At surgery, the mass was located within the epineurium, could be bluntly dissected from the nerve fascicles, and was suspected to be a schwannoma. A 3.4 cm, tan-pink, glistening, smooth, homogenous mass was submitted to pathology. Microscopically, the tumor was a solid and cystic circumscribed nodule with a dense fibrous pseudocapsule. The tumor cells were uniformly bland and spindle-shaped, with small, hyperchromatic oval nuclei and were embedded in an alternating fibrous and myxoid stroma with a prominent curvilinear vasculature and perivascular sclerosis. The differential diagnosis for this lesion included myxoid neurofibroma, schwannoma, soft tissue perineurioma, low-grade malignant peripheral nerve sheath tumor and low-grade fibromyxoid sarcoma. The tumor cells expressed MUC4, GLUT-1, and vimentin and were negative for S-100 protein, epithelial membrane antigen, smooth muscle actin, desmin, claudin-1, neurofilament and SOX10. Fluorescence in situ hybridization, with a break-apart probe strategy, demonstrated FUS rearrangement, consistent in this morphological context with the low-grade fibromyxoid sarcoma-associated FUS-CREB3L2 or FUS-CREB3L1 fusions. Low-grade fibromyxoid sarcoma is exceptionally rare in the peripheral nerve, with only a single previously reported case. Nonetheless, as our case illustrates, this entity must be included in the differential diagnosis of unusual intraneural mesenchymal tumors. As in all other locations, intraneural low-grade fibromyxoid sarcomas should be excised with negative margins. Patients with this disease require long-term clinical follow-up, given this tumor's propensity for very late distant metastases to the lungs and other sites.

Proteases in the Emory mouse cataract

Exopeptidases identified as dipeptidyl peptidase III and leucine aminopeptidase, and an endopeptidase, prolyl endopeptidase, were found in the Emory Mouse cataract and the Cataract Resistant mouse lens extracts. The specific activity measured on Arg-Arg-2-NNap for DPP III and the hydrolysis of Boc-Arg-Pro-2-NNap for prolyl endopeptidase were higher in the Emory Mouse cataractous lens extract. A relatively high rate of hydrolysis of the beta-naphthylamide of leucine aminopeptidase was present in both mouse categories; however, the Cataract Resistant mouse lens had approximately double the protease activity of the Emory Mouse cataract.

Proteases in human lenses and their possible significance

Proteases identified as exopeptidases including dipeptidyl II and III, phenylalanine, leucine, methionine, lysine and alanine aminopeptidases, and prolyl endopeptidase were found in extracts of human fetal lenses. Previous data from normal adult lenses were included for comparison. Except for prolyl endopeptidase and dipeptidyl peptidase II, all protease activities were lower in fetal lenses.

The identification of prolyl endopeptidase in bovine lenses: a preliminary report

A new neutral endopeptidase having the properties of prolyl endopeptidase was detected in bovine lenses. The enzyme hydrolyzed the prolyl bond in the newly-developed fluorogenic substrate, t-butyloxycarbonyl-Arg-Pro-2-NNap, optimally at pH 8 and 37 degrees. The Km value was estimated to be 0.033 mM. An approximately 4-fold purification was achieved. DFP completely inhibited the hydrolysis of Boc-Arg-Pro-2-NNap by the endopeptidase.

Dipeptidyl peptidase III of human cataractous lenses. Partial purification

A partial purification of dipeptidyl peptidase III has been achieved from human cataractous lens. The specific activity was increased 45.5-fold over that of the original aqueous extract. The exopeptidase exhibited a marked preference for the release of Arg-Arg from Arg-Arg-2-NNap at the optimum pH 8.8 and 37 degrees. The Km for this substrate was estimated to be 6.061 X 10(-3). Lens DPP III was inhibited by EDTA, p-chloromercuriphenyl sulfonate, puromycin and DFP. The preparation contained leucyl aminopeptidase and a neutral endopeptidase as contaminating proteases.

Age-related changes in the proteolytic enzymes of mammalian lens

A longitudinal study has been conducted on three exopeptidases which include an esterase, leucine aminopeptidase, and a triglycinopeptidase and two endopeptidases, a neutral protease and a proteinase or catheptic activity in bovine lenses. The esterase and leucine aminopeptidase behave similarily showing increased activities with aging. Triglycinopeptidase has a somewhat lower order of magnitude when compared to the other exopeptidases. The neutral protease shows initially high activity early in the developmental life period, whereas, the proteinase or catheptic activity indicates a continuous increase with aging. Data whereas, the proteinase or catheptic activity indicates a continuous increase with aging. Data is also provided on enzymic activity in the different sections of the lens which include the combined anterior cortex and epithelium, lens nucleus, posterior cortex, and equatorial ring.

Human placental cathepsin B1. Isolation and some physical properties

A reproducible procedure for the isolation, from human placenta, of a cathepsin B1 in a homogeneous state, demonstrated by electrophoretic, ultracentrifugal and enzymic criteria, was carried out. The pH optimum was near pH5.5. The placental enzyme catalysed the release of acid-soluble u.v.-dense products from haemoglobin and myoglobin. It was inhibited by heavy metals and several compounds which react with the thiol groups. The optimum temperature was between 37 degrees and 42 degrees C. The molecular weight of the enzyme was calculated to be 24250.

Elemental analysis of precipitates formed in nuclei by antimonate-osmium tetroxide fixation

Elements retained in cervical lymph nodes, isolated hepatic nuclei and salt-impregnated gels by fixation with antimonate- or pyrophosphate-containing and other osmium tetroxide solutions were assayed by nuclear activation analysis or by atomic absorption spectrophotometry. Salts preserved by the antimonate-osmium tetroxide fixative in lymph nodes, isolated nuclei and a KCl-enriched gel consisted almost entirely of potassium antimonate. The K+ in the precipitates in these specimens appeared to derive partially from that in the fixative solution and partially from that in the specimen. Salts preserved by the antimonate-osmium tetroxide fixative in an NaCl-supplemented gel consisted partly of potassium antimonate derived from the fixative as in unsupplemented gels and partly of sodium antimonate. The Na+ precipitated in this gel amounted to less than one-half that originally present. In comparison the pyrophosphate-osmium tetroxide solution retained higher levels of K+ in lymph nodes, nuclei and the KCl gel, but the potassium pyrophosphate was not evident as electron-opaque precipitates. The latter fixative was less effective in preserving Na+ in the NaCl gel. The pyrophosphate-containing fixative, which was about twice as efficient as the antimonate-containing solution in retaining the divalent cations, preserved 70% of the Mg++ and 100% of the Ca++ added to gels.

Human senile cataractous lens protease. Isolation and some chemical characteristics

A proteolytic enzyme was isolated from human senile cataractous lens by anion-exchange and gel-filtration chromatography. Sedimentation and zone-electrophoretic experiments indicated a high degree of homogeneity for the enzyme. A molecular weight of 27000 was calculated from measurements of sedimentation velocity and diffusion coefficient. Chelating agents decreased activity which could be restored by addition of certain bivalent metal ions. Di-isopropyl phosphorofluoridate and phenylmethanesulphonyl fluoride inhibit the proteolytic activities. Optimum rates of hydrolysis were observed at pH5.2.