Site-directed mutagenesis of human ceruloplasmin:. production of a proteolytically stable protein and structure-activity relationships of type 1 sites

A fully active recombinant human ceruloplasmin was obtained, and it was mutated to produce a ceruloplasmin stable to proteolysis. The stable ceruloplasmin was further mutated to perturb the environment of copper at the type 1 copper sites in two different domains. The wild type and the mutated ceruloplasmin were produced in the yeast Pichia pastoris and characterized. The mutations R481A, R701A, and K887A were at the proteolytic sites, did not alter the enzymatic activity, and were all necessary to protect ceruloplasmin from degradation. The mutation L329M was at the tricoordinate type 1 site of the domain 2 and was ineffective to induce modifications of the spectroscopic and catalytic properties of ceruloplasmin, supporting the hypothesis that this site is reduced and locked in a rigid frame. In contrast the mutation C1021S at the type 1 site of domain 6 substantially altered the molecular properties of the protein, leaving a small fraction endowed with oxidase activity. This result, while indicating the importance of this site in stabilizing the overall protein structure, suggests that another type 1 site is competent for dioxygen reduction. During the expression of ceruloplasmin, the yeast maintained a high level of Fet3 that was released from membranes of yeast not harboring the ceruloplasmin gene. This indicates that expression of ceruloplasmin induces a state of iron deficiency in yeast because the ferric iron produced in the medium by its ferroxidase activity is not available for the uptake.

Surgical treatment of laryngeal carcinoma with subglottis involvement

Primary cancers arising in the subglottic region are rare and are characterized by a long asymptomatic phase. More frequently the subglottis is reached by tumors arising in the glottis or even the supraglottis through invasion of the paraglottic space. Involvement of the subglottis is associated with a relatively high frequency of stomal recurrences due to a peculiar lymphatic spread to the paratracheal nodes. We analyzed a retrospective series of 68 patients with squamous cell carcinoma of the larynx extending to the subglottis region submitted to total simple laryngectomy or total laryngectomy enlarged with hemithyroidectomy and dissection of level VI nodes (HT/SPD). Overall median follow-up is 46 months. Subglottic extension was correctly diagnosed before operation in only 13/68 patients, however the resection margins, systematically determined by the pathologist, were in every case negative. Stomal relapses in laryngectomized patients without HT/SPD have been more frequent (0.55% rate per month) than in those treated with laryngectomy and HT/SPD (0.07% rate per month). It is concluded that CT should be routinely applied in preoperative staging in order to estimate the extension of the neoplasia and surgery should always include hemithyroidectomy and dissection of the homolateral paratracheal nodes when there is even minimal involvement of the subglottis. Moreover, the high incidence of second tumors in our series is noteworthy; such patients might benefit from chemopreventive therapy.

Papillary carcinoma in thyroglossal duct remnants: presentation of four cases and decision procedure for prophylactic thyroid gland dissection

Papillary carcinoma in thyroglossal duct remnants is a rare and usually unexpected finding. It is controversial whether or not prophylactic thyroid gland dissection is necessary in such circumstances. We present our experience of four cases. Based on this, a consideration of published risk factors, and evaluation of the likelihood of a primary versus metastatic origin of the malignancy, we present a therapeutic decision procedure. When the thyroid is normal, the patient presents low-risk factors for thyroid cancer, and there is evidence that the malignancy is primary, removal of all thyroglossal duct remnants by the Sistrunk procedure is sufficient.

Is there a role for sentinel node biopsy in early N0 tongue tumors?

BACKGROUND

Detecting metastases to the cervical lymph nodes is the main problem in the management of squamous cell carcinoma of the tongue. We investigated the ability of sentinel node (SN) biopsy to predict neck status in 11 patients with lateral T1-T2, N0, and M0 squamous cell carcinoma of the tongue who underwent ipsilateral neck dissection 30 to 40 days after primary surgery.

METHODS

In 5 patients, technetium 99m-labeled particles were injected close to the operation scar on the day before neck dissection, and the labeled neck nodes were revealed by lymphoscintigraphy. The next 6 patients underwent lymphoscintigraphy both before surgery and before neck dissection. During neck dissection, the ipsilateral SNs were identified by using a hand-held probe and removed separately.

RESULTS

Three patients (27%) had metastatic neck nodes. In all cases, labeled nodes were revealed by scintigraphy. Ipsilateral SNs were removed from 8 patients and correctly predicted the state of the neck (6 negatives and 2 positives). Lymphoscintigraphy before and after surgery revealed that drainage was modified after surgery in 5 of 6 patients; the pre-surgery drainage pattern varied markedly among the 5 pN0 patients.

CONCLUSIONS

The technique allows easy and safe identification of SNs and shows promise in guiding selective neck dissection. Surgery on the primary tumor often modifies lymphatic drainage, so that SN biopsy may only be useful if the primary operation and neck dissection are performed at the same time.

Thalidomide: current and potential clinical applications

More than three decades after its withdrawal from the world marketplace, thalidomide is attracting growing interest because of its reported immunomodulatory and anti-inflammatory properties. Current evidence indicates that thalidomide reduces the activity of the inflammatory cytokine tumor necrosis factor (TNF)-alpha by accelerating the degradation of its messenger RNA. Thalidomide also inhibits angiogenesis. Recently, the drug was approved for sale in the United States for the treatment of erythema nodosum leprosum, an inflammatory complication of Hansen's disease. However, it has long been used successfully in several other dermatologic disorders, including aphthous stomatitis, Behçet's syndrome, chronic cutaneous systemic lupus erythematosus, and graft-versus-host disease, the apparent shared characteristic of which is immune dysregulation. Many recent studies have evaluated thalidomide in patients with human immunodeficiency virus (HIV) infection; the drug is efficacious against oral aphthous ulcers, HIV-associated wasting syndrome, HIV-related diarrhea, and Kaposi's sarcoma. To prevent teratogenicity, a comprehensive program has been established to control access to the drug, including registration of prescribing physicians, dispensing pharmacies, and patients; mandatory informed consent and education procedures; and limitation of the quantity of drug dispensed. Clinical and, in some patients, electrophysiologic monitoring for peripheral neuropathy is indicated with thalidomide therapy. Other adverse effects include sedation and constipation. With appropriate safeguards, thalidomide may benefit patients with a broad variety of disorders for which existing treatments are inadequate.

Release of highly active Fet3 from membranes of the yeast Pichia pastoris by limited proteolysis

A soluble derivative of Fet3 has been obtained from the methylotrophic yeast Pichia pastoris by limited proteolysis of membrane suspensions with trypsin. The soluble protein and the membrane-bound parent Fet3 have been purified to apparent homogeneity. Soluble Fet3 had molecular mass 100 kDa, while the full-length protein had molecular mass 110 kDa, in line with the expected decrease for cleavage and loss of a single transmembrane helix and a small cytoplasmic domain. The optical and EPR spectra of Fet3 were typical of the multicopper oxidases, indicating the presence of one type 1 blue copper site and a type 2/type 3 copper trinuclear cluster. V(max) values for iron oxidation by P. pastoris Fet3 were obtained similar to human ceruloplasmin and much higher than those reported for Saccharomyces cerevisiae Fet3.

Cervico-thoracic tumors resection through transmanubrial osteomuscular sparing approach

Twelve patients with cervico-thoracic tumors underwent transmanubrial approach during a 1-year period. All but two patients with NSCLC (n = 8), had double approaches. Three cases with cervical esophageal cancer underwent TMA and laparotomy. The last patient underwent TMA for cervical fibrosarcoma. One patient underwent subclavian artery resection, while another one resection of the left brachicephalic vein with graft replacement. Two cases, in the esophageal cancer group, had laryngeal nerve palsy requiring temporary tracheostomy. TMA affords an excellent exposure of the thoracic in/outlet allowing extended resection. Sparing the main osteo-muscular structures, it respects shoulder mobility of the scapular girdle, thus avoiding deformities due to clavicle resection.

Homology modeling of the multicopper oxidase Fet3 gives new insights in the mechanism of iron transport in yeast

Fet3, the multicopper oxidase of yeast, oxidizes extracellular ferrous iron which is then transported into the cell through the permease Ftr1. A three-dimensional model structure of Fet3 has been derived by homology modeling. Fet3 consists of three cupredoxin domains joined by a trinuclear copper cluster which is connected to the blue copper site located in the third domain. Close to this site, which is the primary electron acceptor from the substrate, residues for a potential iron binding site could be identified. The surface disposition of negatively charged residues suggests that Fet3 can translocate Fe(3+) to the permease Ftr1 through a pathway under electrostatic guidance.

Surfing prognostic factors in head and neck cancer at the millennium

The ability to reliably predict cancer outcome could tailor therapy to the aggressiveness of the tumour to achieve the best results in terms of loco-regional control, overall survival and quality of life. Retrospective and prospective clinical trials involving large series of patients have validated some predictive clinical and pathological factors, whereas the utility of many other prognostic factors has not been established. This has led to some confusion in clinical practice. In order to clarify the significance, role and cost of these prognostic factors we carried out a Medline search of all papers published between 1993 and 1998 concerning the reliability and cost of markers with prognostic significance, in head and neck squamous cell carcinoma, and assessed the results according to a number of criteria relating to reliability and cost. Regarding reliability we classified prognostic factors into: (1) those with a proven significance based on the fact that they were unanimously reported as having an independent statistical correlation with outcome and prognosis; and (2) those for which results were not unanimous, and which significance is still controversial. Cost analysis showed a substantial difference between validated tests which are of low cost and experimental tests which are expensive. Based on these data regarding both the reliability and cost of each prognostic factor, we propose guidelines for their use in clinical practice in the year 2000.

The multifunctional oxidase activity of ceruloplasmin as revealed by anion binding studies

The effect of multiple binding of azide, N3-, on the structural and functional properties of ceruloplasmin (CP) has been reinvestigated by means of both spectroscopic and enzymatic techniques. High affinity binding of the anion to human CP resulted in a dramatic increase of the absorbance at 610 nm and in a concomitant decrease of the optical density at 330 nm. The oxidase activity toward Fe(II) was essentially unaffected, while turnover parameters versus nonferrous substrates dramatically changed, with an approximately 100-fold enhancement of the kcat/Km parameter. Chloride at physiological concentration proved to behave very similarly to N3- bound with high affinity, in that it not only induced the spectroscopic changes previously interpreted in terms of an intramolecular electron transfer from reduced type 1 to type 3 copper ions [Musci, G., Bonaccorsi di Patti, M.C. & Calabrese, L. (1995) J. Protein Chem. 14, 611-617], but it also enhanced some 60-fold the kcat/Km value. A different behavior was observed with chicken CP, where a decrease at 330 nm occurred without a concomitant modification at 603 nm. The chicken enzyme was less sensitive also in terms of enzymatic activity, which was nearly unchanged in the presence of either high affinity N3- or Cl-. At higher N3- concentrations, optical changes of both human and chicken CP were mainly focussed on the appearance of ligand-to-metal charge transfer bands below 500 nm, and the anion behaved as an inhibitor of the oxidase activity versus Fe(II) as well as noniron substrates. The well known bleaching of the blue chromophore could be observed, at neutral pH, only at very high N3-/CP ratios. The data presented in this paper are consistent with a mechanism of structural and functional modulation of CP by anions, that would be able to dictate the substrate specificity of the cuproprotein, and suggest the possibility that CP may act in vivo as a multifunctional oxidase.

[Primary neoplasms of the jejunum-ileum. The clinico-diagnostic and surgical therapy considerations: the clinical cases and a retrospective study of our experience]

Primary tumors of the jejunum-ileum are rare and constitute about 2% of gastrointestinal neoplasms. The first clinically reported small bowel tumor was a jejunal carcinoma described in 1824 by Sorlin. The authors reviewed our surgical experience of 9 patients treated at the Department of General Surgery of the "E. Franchini" Hospital of Montecchio Emilia (Re) during a 13-years period from 1984 to 1997. On the basis of literature on the topic, the following are taken into consideration, the history, the incidence, the epidemiology, the aetiopathogenesis, the clinical characteristics, the diagnostic, the surgical therapy of these tumors. The subjects included 6 males and 3 females. The average age of the patients was 66 years, with a male predominance ratio of 2:1. Of the seven primary malignant tumors observed, two patients had adenocarcinomas, two had leiomyosarcomas, two had lymphomas and one carcinoid. The benign tumors were respectively leiomyomas and small intestinal stromal tumor. The most common signs and symptoms were abdominal pain and obstruction of the intestine. Preoperative diagnosis was established in 4 of these patients only by roentgenographic examinations, in 2 by ultrasound scan, in 2 by ultrasound scan and computed tomography, in 1 by endoscopic examination. All the 9 tumors were resected: in 7 patients (77.7%) the resection were considered as curative and in 2 patients (22.3%) palliative. All operated patients were staged by the TNM-classification using pathological and surgical reports. The staging of the disease was the following: 2 patients with stage 1 (T2N0M0), 2 patients with stage II (T4N0M0), 3 patients with stage III (1 with T3N1M0 and 2 with T4N1M0), 2 patients with stage IV (T4N1M1). Survival correlated with the different TNM stage: the median survival time was 60 months for stage I, 60.5 months for stage II, 40 months for stage III and 18 months for stage IV.

[Noninvasive breast carcinomas: anatomicopathological, diagnostic and therapeutic findings]

The carcinoma in situ of the breast is a noninvasive variant of breast cancer which has an favorable prognosis with appropriate management. The widespread use of mammography has contributed to its increased rate of diagnosis. Special attention to the problem of in situ carcinoma is justified by the increasing frequency of its recognition and the controversy surrounding the proper treatment. Carcinoma in situ (CIS) of the breast can be divided in two categories, depending on where it arises: ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS). The two histologic kinds of this cancer have distinct pathologic and biologic characteristics, with different therapeutic implication. The author, on the basis of literature on the topic, reviews present studies of DCIS and LCIS with a particular care for the pathology, the diagnostic approaches and the current treatment of these tumors.

Investigation of the anomalous spectroscopic features of the copper sites in chicken ceruloplasmin: comparison to human ceruloplasmin

Chicken ceruloplasmin has been previously reported to display a number of key differences relative to human ceruloplasmin: a lower copper content and a lack of a type 2 copper signal by electron paramagnetic resonance (EPR) spectroscopy. We have studied the copper sites of chicken ceruloplasmin in order to probe the origin of these differences, focusing on two forms of the enzyme: "resting" (as isolated by a fast, one-step procedure) and "peroxide-oxidized". From X-ray absorption, EPR, and UV/visible absorption spectroscopies, we have shown that all of the copper sites are oxidized in peroxide-oxidized chicken ceruloplasmin and that none of the type 1 copper sites display the EPR features typical for type 1 copper sites that lack an axial methionine. In the resting form, the type 2 copper center is reduced. Upon oxidation, it does not appear in the EPR spectrum at 77 K, but it can be observed by using magnetic susceptibility, EPR at approximately 8 K, and magnetic circular dichroism spectroscopy. It displays unusually fast relaxation, indicative of coupling with the adjacent type 3 copper pair of the trinuclear copper cluster. From reductive titrations, we have found that the reduction potential of the type 2 center is higher than those of the other copper sites, thus explaining why it is reduced in the resting form. These results provide new insight into the nature of the additional type 1 copper sites and the redox distribution among copper sites in the different ceruloplasmins relative to other multicopper oxidases.

On the lability and functional significance of the type 1 copper pool in ceruloplasmin

The possibility that ceruloplasmin (CP) functions as a copper transferase has fueled a continuing interest in studies of the copper release process. The principal goal of the current investigation has been to identify the most labile copper centers in sheep protein. In fact, subjecting the enzyme to a slow flux of cyanide at pH 5.2 under nitrogen in the presence of ascorbate and a phenanthroline ligand produces partially demetalated forms of the protein. By standard chromatographic techniques it is possible to isolate protein with a Cu/CP ratio of approximately 4 or approximately 5 as opposed to the native protein which has Cu/CP = 5.8. In contrast to other blue oxidases, analysis suggests that CP preferentially loses its type 1 coppers under these conditions. Thus, the spectroscopic signals from the type 1 centers exhibit a loss of intensity while the EPR signal of the type 2 copper becomes stronger. Furthermore, the Cu/CP approximately 4 and Cu/ CP approximately 5 components retain about 50% of the activity of the native protein, consistent with an intact type 2/type 3 cluster. All three type 1 copper sites appear to suffer copper loss. Reconstitution with a copper(I) reagent restores the spectroscopic properties of the native protein and 90% of the original activity. The results suggest a possible functional significance for the presence of three type 1 coppers in CP. By employing a pool of redox-active but relatively labile type 1 copper centers, the enzyme can serve as a copper donor, if necessary, without completely sacrificing its oxidase activity.

Inhibition of endothelial nitric-oxide synthase by ceruloplasmin

The plasma copper protein ceruloplasmin (CP) was found to inhibit endothelial nitric-oxide synthase activation in cultured endothelial cells, in line with previous evidence showing that the endothelium-dependent vasorelaxation of the aorta is impaired by physiological concentrations of ceruloplasmin. The data presented here indicate a direct relationship between the extent of inhibition of agonist-triggered endothelial nitric oxide synthase activation and CP-induced enrichment of the copper content of endothelial cells. Copper discharged by CP was mainly localized in the soluble fraction of cells. The subcellular distribution of the metal seems to be of relevance to the inhibitory effect of CP, because it was mimicked by copper chelates, like copper-histidine, able to selectively enrich the cytosolic fraction of cells, but not by copper salts, which preferentially located the metal to the particulate fraction.

[Thrombosis of the portal vein]

The portal venous thrombosis is an infrequent disease that accounts from 0.25 to 1%. The etiopathogenesis is unknown in about one half of cases. Sometimes the thrombosis of mesenterico-portal venous axis is a complication following splenectomy, especially when the operation is performed for hematologic disease. The authors report a clinical case of chronic portal venous thrombosis widespread to superior mesenteric and splenic vein, in man 38 years old after splenectomy, in pediatric age, manifesting with gastrointestinal bleeding due to rupture of esophagogastric varices. On the basis of literature, the following were taken into consideration the incidence, the epidemiology, the aetiopathogenesis, the clinical characteristics, the diagnosis as well as the therapy of portal venous thrombosis.

[Bronchiolo-alveolar carcinoma. The clinico-diagnostic and therapeutic considerations and the results of a retrospective study in our experience]

Bronchioloalveolar carcinoma (BAC) is a subtype of adenocarcinoma of the lung that accounts for 3% of the total pulmonary malignancies. On the basis of literature on the topic, the following were taken into consideration, the history, the incidence, the epidemiology, the aetiopathogenesis, the clinical characteristics, the diagnostic as well as the surgical therapy of this kind of cancer. The authors reviewed our surgical experience of 23 patients treated at the Department of General, Thoracic & Vascular Surgery of the University of Parma during a 10-years period from 1985 to 1995.

Prognostic factors in head and neck oncology: a critical appraisal for use in clinical practice

BACKGROUND

An ideal prognostic factor would provide information about the biological behaviour of a tumour, permitting the prediction of the outcome and response to therapy. Nowadays there is a considerable confusion concerning the value, significance and use of the know prognostic factors in head and neck cancer.

MATERIAL AND METHODS

A meta-analysis of works published in literature between 1993 and August 1997 on prognostic factors in head and neck oncology was carried out.

RESULTS

Prognostic factors were analysed and classified according to Wennenberg in the following groups: patient-related factors, tumour-related factors and factors predicting response to therapy.

CONCLUSIONS

We propose a classification of prognostic factors in head and neck cancer according to their significance and reliability: factors of proven significance and experimental factors. This classification might be useful to select guidelines to use in clinical practice.

Severe back and abdominal pain in a 44-year-old woman

Retroperitoneal fibrosis is an uncommon collagen vascular disease. Back pain with no specific radiation pattern is a common finding. Evaluation usually begins with an abdominal CT scan or MRI. The finding of fibrous periaortic tissue in conjunction with an elevated erythrocyte sedimentation rate supports the diagnosis. A biopsy is necessary to confirm the diagnosis and exclude malignancy. Sometimes retroperitoneal fibrosis can progress to the point of causing bilateral ureteral obstruction leading to acute renal failure. Corticosteroids, in conjunction with surgery when needed, are the mainstay of therapy.

[Endometriosis of the abdominal wall. Clinical case and review of literature]

The authors report a clinical case of endometriosis the abdomen rectum muscle, in woman 28 years old, after a cesarean section delivery. On the basis of literature on the topic, the following are taken into consideration, the incidence, the pathogenesis, the clinical characteristics of this kind of pathology and the aspects which might facilitate the diagnostic approach and correct therapeutic to be given or follow. Parietal endometriosis is an extremely rare disease with incidence in feminine population of 0.03-1%. The pathogenesis is still ill-known. Lack of the classical symptoms and the unusual site can make diagnosis difficult. Pathognomonics but not always present are the presence of tumescence palpable of the abdominal wall near or proximity of preceding surgical scar, the cyclic character of painful symptomatology, the augmentation of volume and the bleeding in period menstrual or premenstrual. The ultrasonography, the computerized axial tomography, the nuclear magnetic resonance can facilitate the preoperative diagnosis but they do not always furnish reports of certainty. The aspirate-needle in ultrasonography control can furnish one of orientation diagnosis. The diagnosis of certainty is founded on the histologic examination after biopsy or excision. The treatment of the abdominal wall endometriosis is surgically essential. The excision of tumescence, easy usually, it is the only means to obtain the definitive recovery. The medical therapy postoperative is adjuvant in the treatment of unrecognized pelvic centres of endometriosis.