Predictive value of staging investigations in patients with clinical stage I malignant melanoma

We reviewed the charts of 393 consecutive patients referred to the Toronto-Bayview Regional Cancer Centre and the Ontario Cancer Institute between January 1, 1978, and December 31, 1982, with clinical stage I malignant melanoma to determine the predictive value of routine staging investigations. The investigations reviewed included physical examination, liver function tests, radionuclide liver-spleen and bone scans, chest x-ray, whole-lung tomograms, CT chest scans, CT brain scans, and bipedal lymphangiograms. The clinical stage of nine patients was changed, eight as a result of physical examination and one as a result of lymphangiogram. No other investigations detected metastatic melanoma at referral. We recommend that staging investigations for patients referred with clinical stage I malignant melanoma be restricted to a complete physical examination and a baseline chest x-ray for all patients.     

131I]metaiodobenzylguanidine therapy in paraganglioma.

Our experience with [131I]metaiodobenzylguanidine (131I-MIBG) therapy in a 10 year old boy is reported. At disease onset, in May 1988, this boy presented a large mass in the upper left abdominal quadrant, which was resected with a histopathological diagnosis of extra-adrenal malignant pheochromocytoma (paraganglioma). He subsequently underwent two further surgical resections and chemotherapy. When 131I-MIBG therapy was started, in June 1990, skeletal and abdominal metastases were present. These localizations were revealed by 131I-MIBG scans and confirmed by x-ray examination. At present 6 courses of therapy have been performed with a cumulative activity of 29.6 GBq. Side-effects have been limited to vomiting and mild thrombocytopenia, lasting 2 weeks during the second course of therapy. After 15 months of therapy, a progressive reduction of MIBG uptake, coupled with a stabilization of the lythic lesions, has been observed.     

THE POTENTIATION OF RADIATION EFFECTS WITH 5-FLUORO-URACIL

A preliminary study of the response of various inoperable malignant diseases to simultaneously administered 5-fluoro-uracil and orthovolt x-ray was performed. The 5-fluoro-uracil was given intravenously at a relatively nontoxic dosage level. The x-ray tumor dose was limited to 2,000 roentgens in every patient.Pronounced and rapid tumor regression occurred in 12 of 18 evaluable patients. Significant objective response was obtained in each of eight patients with epidermoid carcinoma of the lung.Toxicity occurred in half of the patients, manifested by pharyngitis, esophagitis, proctitis, leukopenia and thrombocytopenia.     

Ultrasonographic and radiographic diagnosis of breast nodules in young women]

Mammography as a priority method of diagnosis of breast nodules in young women is of low efficacy as a result of a dense background of the breast as distinct from echography permitting the detection of abnormal lesion against this background. Altogether 126 patients with clinical manifestations of breast nodules were investigated. Apparatus methods used for investigation of 38 of them, revealed but manifestations of fibrocystic mastopathy. Assessment of the efficacy of x-ray and ultrasound diagnostic methods was performed in 88 patients with breast nodules (the patients varied in age from 14 to 40). Radiodiagnostic accuracy in benign tumors was 54.1%, that in malignant tumors--78.1%. Ultrasound investigation proved to be the most informative method for diagnosis of breast nodules in young women, and the use of a proposed algorithm would permit optimization of the diagnostic process.     

Magnetic resonance tomography of malignant tumors of the maxilla]

The authors discussed their experience in investigating 20 patients with maxillary malignant tumors using routine x-ray studies and MR-tomography, and 13 patients, investigated in the same way plus CT. MRT permitted defining a topical localization of a tumor and its spreading to adjacent anatomical regions (the pterygopalatine and infratemporal fossae, pharynx and peripharyngeal space, orbit, buccal soft tissues, and the cranial cavity). MRT was used to differentiate between tumor tissue and inflammation even within the sinus. As to the detection of osseous destruction, CT seemed much more superior than MRT. It was only in one patient that x-ray findings brought about better results than MRT because of artefacts resulting from metal crowns on the affected side.     

X-ray characterization of changes of the lungs in juvenile rheumatoid arthritis

The results of chest x-ray were analyzed in 66 pediatric patients with juvenile rheumatoid arthritis (JRA). X-ray signs of pneumofibrosis were revealed in 37 (56%) patients. Besides, rare pulmonary changes (emphysema, rheumatic nodules, infiltrates) were detected in the JRA patients. The absence of clinical symptoms in the presence of x-ray changes necessitates the performance of chest x-ray in JRA for early detection of the pulmonary symptoms of this disease.     

Pathogenetic mechanisms in immune polioencephalomyelitis: induction of disease in immunosuppressed mice.

Immune polioencephalomyelitis (IPE) was induced by the i.p. injection of x-irradiated (10, 000 R) syngeneic line Ib malignant lymphocytes into C58 mice that were 7 or more months old and in young mice immunosuppressed by x-ray or drugs. The occurrence of IPE in young immunosuppressed C58 mice was systematically analyzed. When mice less than 2 weeks old were x-irradiated with 600 R, IPE could not be induced. The incidence in 1-month-old mice was approximately 50% and increased progressively with the age except for a drop in incidence at 3 months. An analysis of the dose effects of x-irradiation on the occurrence of IPE in mice of different ages revealed a marked increase in the incidence in 3- and 5-month-old mice beginning at dose levels of 450 R and 300 R, respectively. Considered together, these data indicated that two subpopulations of immunocytes differing in x-ray sensitivity interacted to protect mice from IPE. It appears that under natural conditions an x-ray sensitive cell population, possibly having suppressor function, decreased with age and made mice susceptible ot induction of IPE. Five-month-old mice were immunosuppressed with an LD10 of cyclophosphamide, prednisolone, or methotrexate to determine whether mice immunosuppressed with drugs also were susceptible to the induction of IPE. The incidence was 89%, 13%, and 5%, respectively. The mouse strain specificity of IPE induction also was studied. In 6- to 8-month-old mice suppressed with 600 R, IPE could not be induced in non-H-2k strains: BALB, C57BL/6, NZB. Of the H-2K strains tested (CBA/J, C3H/He, AKR/J, C58), the disease could be induced only in the C58 and AKR/J strains. Histopathologic studies showed that CNS lesions in immunosuppressed C58 and AKR/J mice did not differ significantly from those in old C58 mice with IPE. Taken together, the results of these studies indicate that IPE can be used as a model for analyzing age-dependent diseases of suspected immunopathologic etiology.     

High resolution crystal structures of the trans-enamine intermediates formed by sulbactam and clavulanic acid and E166A SHV-1 {beta}-lactamase

Antibiotic resistance mediated by constantly evolving beta-lactamases is a serious threat to human health. The mechanism of inhibition of these enzymes by therapeutic beta-lactamase inhibitors is probed using a novel approach involving Raman microscopy and x-ray crystallography. We have presented here the high resolution crystal structures of the beta-lactamase inhibitors sulbactam and clavulanic acid bound to the deacylation-deficient E166A variant of SHV-1 beta-lactamase. Our previous Raman measurements have identified the trans-enamine species for both inhibitors and were used to guide the soaking time and concentration to achieve full occupancy of the active sites. The two inhibitor-bound x-ray structures revealed a linear trans-enamine intermediate covalently attached to the active site Ser-70 residue. This intermediate was thought to play a key role in the transient inhibition of class A beta-lactamases. Both the Raman and x-ray data indicated that the clavulanic acid intermediate is decarboxylated. When compared with our previously determined tazobactam-bound inhibitor structure, our new inhibitor-bound structures revealed an increased disorder in the tail region of the inhibitors as well as in the enamine skeleton. The x-ray crystallographic observations correlated with the broadening of the O-C=C-N (enamine) symmetric stretch Raman band near 1595 cm(-1). Band broadening in the sulbactam and clavulanic acid inter-mediates reflected a heterogeneous conformational population that results from variations of torsional angles in the O-(C=O)-C=C=NH-C skeleton. These observations led us to conclude that the conformational stability of the trans-enamine form is critical for their transient inhibitory efficacy.     

The crystal and solution structures of glyceraldehyde-3-phosphate dehydrogenase reveal different quaternary structures

The presence of an isoform of glyceraldehyde-3-phosphate dehydrogenase (kmGAPDH1p) associated with the cell wall of a flocculent strain of Kluyveromyces marxianus was the first report of a non-cytosolic localization of a glycolytic enzyme, but the mechanism by which the protein is transported to the cell surface is not known. To identify structural features that could account for the multiple localizations of the protein, the three-dimensional structure of kmGAPDH1p was determined by x-ray crystallography and small angle x-ray scattering. The x-ray crystallographic structure of kmGAPDH1p revealed a dimer, although all GAPDH homologs studied thus far have a tetrameric structure with 222 symmetry. Interestingly, the structure of kmGAPDH1p in solution revealed a tetramer with a 70 degrees tilt angle between the dimers. Moreover, the separation between the centers of the dimers composing the kmGAPDH1p tetramer diminished from 34 to 30 A upon NAD(+) binding, this latter value being similar to the observed in the crystallographic models of GAPDH homologs. The less compact structure of apo-kmGAPDH1p could already be the first image of the transition intermediate between the tetramer observed in solution and the dimeric form found in the crystal structure, which we postulate to exist in vivo because of the protein's multiple subcellular localizations in this yeast species.     

Imaging of Metastatic Lymph Nodes by X-ray Phase-Contrast Micro-Tomography

Invasive cancer causes a change in density in the affected tissue, which can be visualized by x-ray phase-contrast tomography. However, the diagnostic value of this method has so far not been investigated in detail. Therefore, the purpose of this study was, in a blinded manner, to investigate whether malignancy could be revealed by non-invasive x-ray phase-contrast tomography in lymph nodes from breast cancer patients. Seventeen formalin-fixed paraffin-embedded lymph nodes from 10 female patients (age range 37–83 years) diagnosed with invasive ductal carcinomas were analyzed by X-ray phase-contrast tomography. Ten lymph nodes had metastatic deposits and 7 were benign. The phase-contrast images were analyzed according to standards for conventional CT images looking for characteristics usually only visible by pathological examinations. Histopathology was used as reference. The result of this study was that the diagnostic sensitivity of the image analysis for detecting malignancy was 100% and the specificity was 87%. The positive predictive value was 91% for detecting malignancy and the negative predictive value was 100%. We conclude that x-ray phase-contrast imaging can accurately detect density variations to obtain information regarding lymph node involvement previously inaccessible with standard absorption x-ray imaging.     

Endoscopic brushing cytology of primary gastric choriocarcinoma. A case report.

A rare primary choriocarcinoma of the stomach developed in a 71-year-old woman admitted with epigastric pain and weight loss. Brushing smears revealed highly atypical malignant cells with bizarre nuclei and prominent nucleoli. Multiple histologic sections revealed pure choriocarcinoma. Human chorionic gonadotropin and keratin were demonstrated in malignant cells by immunohistochemistry.     

The problem of instability of perception and interpretation of x-ray images of spheroidal lung formations

Sixteen radiologists analyzed twice 44 sets of x-ray films of verified spheroidal lung formations (SLF), copied the images through a transparent film. High instability of image-bearing and speech perception of all x-ray signs of SLF was revealed. It greatly influenced diagnostic effectiveness in informative uncertainty of images. The author substantiated methodological approaches to further work at increasing the effectiveness of radiodiagnosis of this pathology.     

Pyrococcus horikoshii TET2 Peptidase Assembling Process and Associated Functional Regulation

Tetrahedral (TET) aminopeptidases are large polypeptide destruction machines present in prokaryotes and eukaryotes. Here, the rules governing their assembly into hollow 12-subunit tetrahedrons are addressed by using TET2 from Pyrococcus horikoshii (PhTET2) as a model. Point mutations allowed the capture of a stable, catalytically active precursor. Small angle x-ray scattering revealed that it is a dimer whose architecture in solution is identical to that determined by x-ray crystallography within the fully assembled TET particle. Small angle x-ray scattering also showed that the reconstituted PhTET2 dodecameric particle displayed the same quaternary structure and thermal stability as the wild-type complex. The PhTET2 assembly intermediates were characterized by analytical ultracentrifugation, native gel electrophoresis, and electron microscopy. They revealed that PhTET2 assembling is a highly ordered process in which hexamers represent the main intermediate. Peptide degradation assays demonstrated that oligomerization triggers the activity of the TET enzyme toward large polypeptidic substrates. Fractionation experiments in Pyrococcus and Halobacterium cells revealed that, in vivo, the dimeric precursor co-exists together with assembled TET complexes. Taken together, our observations explain the biological significance of TET oligomerization and suggest the existence of a functional regulation of the dimer-dodecamer equilibrium in vivo.     

Architecture of a full-length retroviral integrase monomer and dimer, revealed by small angle X-ray scattering and chemical cross-linking

We determined the size and shape of full-length avian sarcoma virus (ASV) integrase (IN) monomers and dimers in solution using small angle x-ray scattering. The low resolution data obtained establish constraints for the relative arrangements of the three component domains in both forms. Domain organization within the small angle x-ray envelopes was determined by combining available atomic resolution data for individual domains with results from cross-linking coupled with mass spectrometry. The full-length dimer architecture so revealed is unequivocally different from that proposed from x-ray crystallographic analyses of two-domain fragments, in which interactions between the catalytic core domains play a prominent role. Core-core interactions are detected only in cross-linked IN tetramers and are required for concerted integration. The solution dimer is stabilized by C-terminal domain (CTD-CTD) interactions and by interactions of the N-terminal domain in one subunit with the core and CTD in the second subunit. These results suggest a pathway for formation of functional IN-DNA complexes that has not previously been considered and possible strategies for preventing such assembly.     

The Management of Benign Bone Lesions

The almost bewildering variety of lesions that can affect bone contrasts sharply with the limited potential of bone to differentially respond to those lesions. This paradox can create a challenging problem when a bone lesion is shown on an x-ray film. Although heavily populated with pleuripotential primitive mesenchymal cells, there is seldom a histologic or radiographic change in the involved bone specific enough to allow a comfortable diagnostic autonomy to be enjoyed by surgical pathologists, radiologists or orthopaedic surgeons. Even when diligent and astute clinical evaluation has excluded infectious, parasitic, metabolic and metastatic causes of the change seen on x-ray studies, a physician is often still uncertain as to the exact nature of the lesion. A knowledge of the relative frequency of the common lesions, an acceptance that biopsy studies and treatment must be combined at times, an appreciation of the possibility of malignant change in a given lesion and a tendency to seek early consultation will likely lead to timely and accurate diagnosis. Once the diagnosis is made, optimum management must be selected. The best current opinion categorizes the lesions into treatment groups consisting of observation, curettage and graft, block excision, cryotherapy and radiotherapy.     

A complex x-ray study of patients with enterocutaneous fistulas

The paper is concerned with analysis of the results of x-ray examination of 78 patients with enterocutaneous fistulas of various etiology and site. The authors have shown the characteristic features of x-ray examination of patients in whom the fistulas were at the acute phase of their development. They have also defined the diagnostic value of the employed methods and their efficacy for the diagnosis not only of fistulas but also of related complications (inflammatory infiltrates and abscesses of the abdominal cavity, fatty phlegmon, purulent "fillings", complicated fistulas, etc.). During combined x-ray investigation accurate diagnosis of fistulas was established in 97.4% of the patients, purulent complications were revealed in 94.6%.     

Conformational Analysis of the Streptococcus pneumoniae Hyaluronate Lyase and Characterization of Its Hyaluronan-specific Carbohydrate-binding Module

For a subset of pathogenic microorganisms, including Streptococcus pneumoniae, the recognition and degradation of host hyaluronan contributes to bacterial spreading through the extracellular matrix and enhancing access to host cell surfaces. The hyaluronate lyase (Hyl) presented on the surface of S. pneumoniae performs this role. Using glycan microarray screening, affinity electrophoresis, and isothermal titration calorimetry we show that the N-terminal module of Hyl is a hyaluronan-specific carbohydrate-binding module (CBM) and the founding member of CBM family 70. The 1.2 Å resolution x-ray crystal structure of CBM70 revealed it to have a β-sandwich fold, similar to other CBMs. The electrostatic properties of the binding site, which was identified by site-directed mutagenesis, are distinct from other CBMs and complementary to its acidic ligand, hyaluronan. Dynamic light scattering and solution small angle x-ray scattering revealed the full-length Hyl protein to exist as a monomer/dimer mixture in solution. Through a detailed analysis of the small angle x-ray scattering data, we report the pseudoatomic solution structures of the monomer and dimer forms of the full-length multimodular Hyl.     

Strong binding of myosin heads stretches and twists the actin helix

Calculation of the size of the power stroke of the myosin motor in contracting muscle requires knowledge of the compliance of the myofilaments. Current estimates of actin compliance vary significantly introducing uncertainty in the mechanical parameters of the motor. Using x-ray diffraction on small bundles of permeabilized fibers from rabbit muscle we show that strong binding of myosin heads changes directly the actin helix. The spacing of the 2.73-nm meridional x-ray reflection increased by 0.22% when relaxed fibers were put into low-tension rigor (<10 kN/m(2)) demonstrating that strongly bound myosin heads elongate the actin filaments even in the absence of external tension. The pitch of the 5.9-nm actin layer line increased by approximately 0.62% and that of the 5.1-nm layer line decreased by approximately 0.26%, suggesting that the elongation is accompanied by a decrease in its helical angle (approximately 166 degrees) by approximately 0.8 degrees. This effect explains the difference between actin compliance revealed from mechanical experiments with single fibers and from x-ray diffraction on whole muscles. Our measurement of actin compliance obtained by applying tension to fibers in rigor is consistent with the results of mechanical measurements.     

Small-angle X-ray Scattering of Apolipoprotein A-IV Reveals the Importance of Its Termini for Structural Stability

ApoA-IV is an amphipathic protein that can emulsify lipids and has been linked to protective roles against cardiovascular disease and obesity. We previously reported an x-ray crystal structure of apoA-IV that was truncated at its N and C termini. Here, we have extended this work by demonstrating that self-associated states of apoA-IV are stable and can be structurally studied using small-angle x-ray scattering. Both the full-length monomeric and dimeric forms of apoA-IV were examined, with the dimer showing an elongated rod core with two nodes at opposing ends. The monomer is roughly half the length of the dimer with a single node. Small-angle x-ray scattering visualization of several deletion mutants revealed that removal of both termini can have substantial conformational effects throughout the molecule. Additionally, the F334A point mutation, which we previously showed increases apoA-IV lipid binding, also exhibited large conformational effects on the entire dimer. Merging this study''s low-resolution structural information with the crystal structure provides insight on the conformation of apoA-IV as a monomer and as a dimer and further defines that a clasp mechanism may control lipid binding and, ultimately, protein function.