Enhanced expression of glucose-6-phosphate dehydrogenase in human cells sustaining oxidative stress

Recent reports have demonstrated that glucose-6-phosphate dehydrogenase (G6PD) activity in mammalian cells is necessary in order to ensure cell survival when damage is produced by reactive oxygen intermediates. In this paper we demonstrate that oxidative stress, caused by agents acting at different steps in the biochemical pathway controlling the intracellular redox status, determines the increase in G6PD-specific activity in human cell lines of different tissue origins. The intracellular level of G6PD-specific mRNA also increases, with kinetics compatible with the induction of new enzyme synthesis. We carried out experiments in which cells were exposed to oxidative stress in the presence of inhibitors of protein or RNA synthesis. These demonstrated that increased G6PD expression is mainly due to an increased rate of transcription, with a minor but significant contribution of regulatory mechanisms acting at post-transcriptional levels. These results provide new information on the defence systems that eukaryotic cells possess in order to prevent damage caused by potentially harmful oxygen derivatives.

[Perforated diverticulum of the cecum: a difficult preoperative diagnosis]

A patient was admitted for a suspected appendicitis; occasionally, a roentgenogram of abdomen, an echography and a tomography: confirmed the suspect. At laparotomy a perforated diverticulum of cecum is suddenly reported: a segmentary resection of ascending colon is performed. Authors remark, according to literature, that preoperative diagnosis of perforated cecal diverticulum is difficult even today, in spite of diagnostic procedures.

[The superior vena cava occlusion syndrome. A case of neoplastic thrombosis due to hepatocarcinoma and cirrhosis]

The authors report their experience with 11 patients, surgically treated since 1990, affected with superior vena cava syndrome. A peculiar case of neoplastic thrombosis in hepatocarcinoma is stressed. In fact a similar case hadn't been reported in the last ten-year literature, although hepatocarcinoma may spread in different organs. A subject review and a discussion are presented.

Surgical treatment of carotid kinking

The authors take in exam 34 anatomical variation in the extracranial internal carotid artery (compared with more than 450 operated carotid artery), 15 of which involved kinking in patients with overt neurological symptoms, underwent corrective surgical treatment, and test the most useful and appropriate techniques in any case.

[Cystic lymphangioma of the transverse mesocolon simulating neoplasm of the pancreatic tail]

Mesenteric cysts are uncommon lesions interesting surgeons above all for frequently difficulties in the preoperatory diagnosis. The role of radiology is to demonstrate the nature of these abdominal masses, but only with surgery we can establish a definitive histologic diagnosis. The authors report a case of a lynphangioma of the transverso mesocolon, miming a pancreatic neoplasm.

[Spinal cord protection in surgery of the thoracic, descending, and thoraco-abdominal aorta. Comparison of methods]

The authors compare the strategus needed for the elimination of paraplegia and for protection of abdominal organs after replacement of descending thoracic or thoraco-abdominal aorta. They analyse single technique considering the advantages and the controindications; furthermore they compare these properties and those of possible variants in the light of the presentation; type of disease and general conditions of the patient. These considerations are in agreement with later literature as well as the attitude of the surgeon.

Localization of the dystrophin binding site at the carboxyl terminus of beta-dystroglycan

Alpha- and beta-dystroglycan form a heteromeric transmembrane complex linking the extracellular matrix to the cytoskeleton. In muscle beta-dystroglycan interacts with dystrophin on the inside of the cell and with alpha-dystroglycan, which binds the extracellular matrix protein laminin, on the outside. Dystroglycan is expressed not only in muscle but also in other tissues. We cloned beta-dystroglycan from rabbit brain by RT-PCR and expressed deletion mutants of the beta-dystroglycan cytoplasmic domain as GST-fusion proteins. We identified the dystrophin binding region on beta-dystroglycan by protein overlay and co-precipitation assays with skeletal muscle dystrophin and recombinant apo-dystrophin I. We demonstrate that the beta-dystroglycan carboxyl terminus interacts with dystrophin and that the binding site is restricted to the last 20 amino acids. Our data also suggest that the region adjacent to the beta-dystroglycan transmembrane domain might modulate beta-dystroglycan-dystrophin interaction.

Pharmacological characterization of the ETA receptor in the vascular smooth muscle comparing its analogous distribution in the rat mesenteric artery and in the arterial mesenteric bed

The potency of ET-1, ET-2, and ET-3 to contract the isolated perfused rat arterial mesenteric bed was 2.73 +/- 0.57, 1.63 +/- 0.32, and 144 +/- 30 nM, respectively. The vasomotor effect of the ETs was slow in onset, persistent but reversible. Sarafotoxin S6b mimicked the ETs with a potency twofold lower than ET-1; sarafotoxin S6c and the C-terminal hexapeptide of ET-1 was inactive. ETH agonists such as IRL-1620 and AGETB-89 were inactive as vasoconstrictors within the range of concentrations examined. Minor chemical modifications of ET-1 amino acids residues in position 7 or 21 decreased significantly the peptide potency; ET-1 analogues with one or none of the disulfide bonds resulted inactive. The vasomotor effect of ETs was blocked in a competitive, reversible, and selective manner by FR 139317 and BQ-123, the latter being about threefold less potent than the former antagonist. The potency of FR 139317 was 20-fold higher to antagonize ET-3 than ET-1, and threefold higher to block ET-2 than ET-1. In strict analogy to FR 139317, BQ-123 was 12-fold more potent to antagonize ET-3 than ET-1, and fourfold more potent to antagonize ET-2 than ET-1. Upon removal of the endothelial cell layer, the vasomotor potency of ET-1 or the antagonist potency of FR 139317 remained unaltered, suggesting that the vasomotor receptors are localized in the arterial smooth muscles. The ET-1-induced vasomotor responses desensitized, an effect not crossed to noradrenaline (NA); perfusion with 10 microM indomethacin did not alter the vasomotor potency of ET-1, excluding the participation of eicosanoids in the arteriolar effects of ET-1. In isolated rings of the rat mesenteric artery, set to record isometric contractions of the circular muscular layer, the potency of the ETs and their structural analogues was as follows; ET-2 = ET-1 = sarafotoxin S6b > ET-3 > sarafotoxin S6c. The C-terminal hexapeptide of ET-1 and [Ala 1,3,11,15]ET-1 were inactive. The ET-1-induced vasoconstriction was antagonized in a concentration-dependent fashion by FR 139317. These results allow to conclude that the ETA receptors present in the arterial mesenteric circulation are localized in the vascular smooth muscle of the large-sized arteries as well as the smaller arterioles and precapillary vessels of the rat arterial mesenteric bed.

[When to combine internal sphincterotomy with hemorrhoidectomy]

396 patients, treated with hemorrhoidectomy (278 Parks, 118 Milligan-Morgan) were submitted to preoperative manometry, which, in 158 patients (39.9%), revealed high anal resting pressure (TBS), with or without an associated anal fissure; this group was submitted to a regulated lateral sphincterotomy (SILR) in association with the haemorroidectomy. The manometric follow-up, two mounts after the operations showed similar TBS values in both groups of patients. The authors conclude that normal values of TBS after Hemorroidectomy can be reached only by associating sphincterotomy in manometrically selected cases.

[Anorectal manometry in hemorrhoidal disease]

Manometry is an important approach to anorectal function. In the haemorrhoids the evaluation of the anal resting tone, of the squeeze and of the sphincterial length is very useful to realize the best surgical treatment. Anorectal manometry is neither invasive nor expensive; it can be ready repeated and the results are reproducible. This examination must be considerated as essential part of the diagnostic routine of the anorectal diseases.

[Submucosal reconstructive hemorrhoidectomy (A.G. Parks operation)]

Indications and procedure of submucosal reconstructive hemorrhoidectomy (A.G. Parks hemorrhoidectomy) are described and discussed. This procedure is more difficult and time consuming than other techniques, but results are better in high degree hemorrhoids. Authors consider complications and sequelae on 278 patients operated in their Department.

[Pseudoaneurysms after carotid endarterectomy]

Pseudoaneurysms after TEA of the internal carotid artery are one of the rarest and most severe complications of this form of surgery. Their etiology appears to depend on 3 causes: a suturing defect due to technical errors made by the surgeon or to the incorrect choice of threads; an infections, and lastly the arterial wall weakened by TEA. The patch increases the risk of false aneurysm approximately four fold. We therefore agree with other authors that, in spite of the undoubted value of the patch in the prevention of restenosis, it must only be used in the presence of an internal carotid of small diameter (less than 4 mm). Contrary to what is reported in the literature we performed both these operations under loco-regional anesthesia and a detailed knowledge of this method allows is to be performed on the carotid axis. Only through a careful follow-up of all the carotids operated can the small dilations which often do not require surgical treatmente identified. The two cases reported here were treated by the removal of the pseudoaneurysms and its replacement with a prosthesis in one case and with the vena saphena in the other. Both were monitored with clinical examination and echo-Doppler and no recidivation has been reported to date.

Central venous catheterization in pediatric patients affected by hematological malignancies

The objective of this retrospective study was to evaluate the significance and complications of percutaneous central venous catheterization in pediatric patients affected by hematologic malignancies. One hundred and fifty-eight central venous catheters were inserted in 125 pediatric patients (male/female 67/58; median age: 4 years; range 10 m - 6 y.) affected by hematological malignancies. Venous access was obtained by means of a tunnelled silicone rubber Groshong catheter inserted percutaneously in the subclavian vein (91.1%), the internal jugular vein or in the femoral vein. The medial duration of catheterization was 231.8 days (range 8-1014 days). The total number of catheter days was 33,792 (92.6 years). There were no complications related to catheter insertion. Only one patient developed significant post-operative bleeding. One hundred and nine catheters (68.9%) were removed when they were no longer needed and 49 (31.1%) were removed due to complications: 6 catheter occlusions (12.2%), 7 were accidentally withdrawn (14.3%), 3 for local infections (6.1%) and 33 for catheter-related infection (67.3%). A Groshong catheter seems to provide good access to the blood stream for a long period of time with a low incidence of complications in children with acute hematological malignancies.

[Relapsing epistaxis: embolization as treatment of choice]

Epistaxis is a very common disease. Fortunately it occurs most commonly in the anterior septal network of blood vessel and is therefore readily controlled with simple local measures. Severe posterior epistaxis is less frequent but is still a common and much more serious clinical problem and usually requires hospitalization. The classic treatment of these epistaxis is combined anterior-posterior nasal packing. Occasionally, however, this treatment does not control bleeding. The most popular alternative for these patient is arterial ligation. Initially only carotid ligation was performed. Later further advances in surgical technique and instrumentation, permitted internal maxillary and etmoid artery ligation to be carried out. However often arterial ligation cannot be easily performed in some ent departments and furthermore, surgical failure rate is not exceptionally high if one consider the numerous hypsilateral-contralateral arterial anastomoses present in the etmoid-nasal region. Fifteen patients with recurring nasal bleeding were treated with embolization between 1991 and 1993. Ten of them suffered of essential epistaxis while the other five had chronic local and/or systemic diseases (hereditary haemorrhagic teleangectasia and angiomas). Analysis of the results show a good control of bleeding in the first group of patients (90% after one embolization) and a satisfactory control in patients with haemorrhagic teleangectasia. In conclusion, owing to its efficacy, speed and safety therapeutic embolization with PVA particles may be considered treatment of choice in recurrent persistent epistaxis.

[Cervical-mediastinal emphysema of abdominal origin]

Cervical mediastinic emphysema usually does not demand emergency procedures: nevertheless its ethiology must be promptly assessed though his achievement may prove less than easy owing the vague clinical presentation and to the limits imposed by regional topography. Among the possible etiologic factors one should take into account the rare abdominal source too. Indeed the cervical region is connected to the retroperitoneal space through a virtual "visceral space" via the thoracic cavity and some diaphragmatic break-throughs variable in size. The communication allows, in some pathologic conditions, the unopposed circulation of air and fluids. Our interest in the topic is due to the occurrence of a cervical mediastinic emphysema in a patient suffering from a colonic perforation.

Control of post anaesthetic shivering with nefopam hydrochloride in mildly hypothermic patients after neurosurgery

Postoperative shivering may be prevented by maintaining normothermia intraoperatively or it may be treated using specific drugs. The aim of this study was to compare the efficacy of nefopam hydrochloride (nefopam) to that of clonidine and meperidine in patients undergoing elective neurosurgical procedures. Three groups of patients were included in the study. Patients in group A (60) received i.v., at random, 20 mg of nefopam, 50 mg of meperidine or 150 micrograms of clonidine in the immediate postoperative period. The incidence of shivering and the time at which shivering ceased were noted, along with central temperature and main haemodynamic changes. Group B (20) received i.v., at random, either 10 mg of nefopam or saline before awakening from anaesthesia. The effects of nefopam on central temperature, oxygen consumption (Vo2), carbon dioxide production (VcO2), basal metabolic rate (BMR) and energy expenditure (EE) were investigated. Group C (10) received i.v. 20 mg of nefopam during surgery: cerebrospinal fluid pressure (CSFP), cerebral perfusion pressure (CPP) and electroencephalogram (EEG) were monitored. In group A nefopam stopped shivering in 95% of patients when compared to meperidine and clonidine, which were effective in 32% and 40% of patients respectively. In group B, only 10% of patients receiving nefopam had postoperative shivering, Vo2, VcO2 and EE were significantly lower in patients treated with nefopam than those in the control group. No changes in CSFP, CPP or EEG were observed in group C. In conclusion, nefopam seems to be more effective than clonidine or meperidine in quickly suppressing shivering, without producing significant adverse reactions.

High IL-6 serum levels are associated with septic shock and mortality in septic patients with severe leukopenia due to hematological malignancies

The serum levels of immunoreactive interleukin-6 (IL-6) and tumor necrosis factor (TNF) were analyzed in 14 leukopenic patients with documented sepsis, at 60 min (T0), 24 h (T1), and one week (T3) after the onset of sepsis syndrome. Sera from 10 leukopenic patients without sepsis (controls) were also tested. All septic patients had high IL-6 levels at T0. These levels persisted only in the seven patients who died of septic shock, presenting a 30-fold increase (p<0.001) as compared to the survivors and the controls. At T3, 7 survivors had recovered from sepsis and showed low IL-6 serum levels. The TNF serum concentration always <30 pg/ml in both the subjects and in the controls. The C-reactive protein (CRP) and clinical parameters appeared to be less specifically associated with shock and mortality than IL-6.

[Appendicular mucocele. A report of a case diagnosed preoperatively]

Mucocele of the appendix is an unusual clinical entity. Despite a recognized constellation of findings, the diagnosis is not usually made prior to surgical exploration. A 35 year old man is reported in whom clinical evaluation, including US and CT scans, resulted in the correct preoperative diagnosis confirmed at surgery and leading to appropriate operative decisions.

[Invasion of the chest wall in primary lung neoplasms]

The authors analyse a series of 5 patients who underwent pulmonary and parietal resection between 1990 and 1993 due to non.microcytoma bronchogenic carcinoma with invasion of the thoracic wall. The patients comprised four men and one woman aged between 45 and 69 years old. Thoracic pain was present in two patients. Pulmonary resection with extrapleural stripping was performed in two patients whereas a block resection from one to five ribs and the corresponding intercostal spaces was performed in the other three patients. The authors' approach is not to perform these operations according to rigid protocols but to adapt them according to the local status of tumour invasion. Therefore to resort to extrapleural resection when there is a free cleavage plane between parietal pleura and rib wall; resection in block of the wall where the carcinoma has infiltrated the endothoracic fascia or deeper. The authors do not report any major complications and record a postoperative mortality rate of 0%. In two cases the thoracic wall was reconstructed using a sheet of Gore-Tex which did not provoke rejection phenomena. Radiotherapy was carried out in cases with positive lymph nodes. The series presented here is too recent to provide significant data regarding survival. However, the only factor seen to influence prognosis in the five patients was the presence or otherwise of lymph node metastasis, irrespective of the histological type and operation performed. The five year survival rate of T3N0M0 patients is in fact similar to that of T2N0M0 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Iron uptake from lactoferrin by intestinal brush-border membrane vesicles of human neonates

It is uncertain to what extent the binding of human lactoferrin (LF) to its receptor in the intestinal brush-border membrane affects iron uptake in infants. The purpose of this study was to investigate iron uptake from human LF by brush-border membrane vesicles (BBMV) obtained from the small intestine of human neonates. LF was purified from pooled human colostrum. Uptake experiments were performed by incubation of 55Fe-citrate or 55Fe-LF with BBMV, followed by rapid filtration through microporous filters. 55Fe uptake from LF by BBMV was dependent on pH, with a maximum at 7.5, and increased with incubation time, reaching a maximum at 1 min. When 55Fe was bound to citrate, uptake was slower (maximum at 5 min) and not dependent on pH. In both experiments, the maximum uptake of iron bound to LF was about twice that of iron bound to citrate (230 pmol and 105 pmol/mg microvillus protein, respectively). Partial degradation of LF in two fragments resulted in the loss of its capacity to increase iron uptake by BBMV. From these preliminary results we conclude that LF may increase iron absorption during the neonatal period, contributing to the high bioavailability of this mineral in human milk.

Coagulation study in patients who had undergone surgery for meningioma

Abnormal fibrinolysis and thrombotic complications have been often observed in patients who had undergone surgery for meningioma. Fourteen patients, affected by meningioma, were studied before surgery, during surgery and 24 h after surgery in order to evaluate the modifications of the fibrinolysis system and the coagulation physiological inhibitors. Before surgery, no patient showed hyperfibrinolysis and/or modifications of coagulation physiological inhibitors. During surgery, an activation of fibrinolysis with pathological levels of tissue plasminogen activator activity (mean = 6.33 U/dl, SD = 7.9, p = 0.02) and increased levels of fibrin degradation products (mean = 0.21, SD = 0.18, p = 0.002) was noted. Modifications of the fibrinolysis parameters occurred only in 9/14 patients (64%). These patients presented a more vascularized tumour, revealed before surgery by computerized tomography scan and cerebral arteriography and directly confirmed during the resection. Twenty-four hours after surgery no patient presented fibrinolysis activation. There was no evidence of disseminated intravascular coagulation in our patients. None of them presented pathological decrease of the physiological coagulation inhibitors or thrombotic complications. In conclusion, during surgery, fibrinolysis parameters show important modifications in patients with vascularized meningioma suggesting an ongoing tumour-host interaction. These variations must be taken in account, in order to plan timely a correct therapeutic approach.