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Biomedical subjects

A Rizzo

Publications and source records attributed to A Rizzo.

At least 55 records · Page 3Linked to original sources
PubMed1998

A Simple Strategy for Treating Persistent Subcutaneous Cerebrospinal Fluid (CSF) Collections Following Complex Neurosurgical Procedures.

Subcutaneous CSF (CSF "pseudocyst") may occur following complex skull base operations. They may respond to a trial of compressive bandages and continuous lumbar drainage that can resolve over months. When this management strategy fails, reoperation is an option, which however would require complex reconstructive procedures at the base of the skull, and still have the chance of not resolving the problem.We describe here a simple alternative treatment, consisting of a "pseudocyst"-peritoneal shunting using a flow-regulated unishunt system. This management strategy has been used successfully in two cases showing subcutaneous CSF collections following complex skull base surgery procedures which did not respond to a trial of conservative management. A prompt resolution of such a complication was achieved in all cases, which persisted during the follow-up (7 to 19 months, averaging 12 months). "Pseudocyst"-peritoneal shunting using a flow-regulated valve can be a very simple though effective management option for persistent CSF subcutaneous collections following major neuro-surgical procedures.

Journal Article↗
PubMed1998

Application of liquid chromatography-atmospheric pressure chemical ionization mass spectrometry and tandem mass spectrometry to the determination of volatile nitrosamines in dry sausages.

A high-performance liquid chromatographic-atmospheric pressure chemical ionization mass spectrometric method was developed for the determination of volatile nitrosamines in dry sausages. Tandem mass spectrometry was applied for the detection of N-nitrosopyrrolidine, N-nitrosodiethylamine and N-nitrosopiperidine. N-nitrosomethylamine was detected by using the selected ion monitoring mode. The occurrence of the four different nitrosamines was monitored in 27 dry sausage samples and a correlation was observed between N-nitrosopyrrolidine and biogenic amines. Nitroso compounds are thus not only formed in heated conditions but formation can also occur during ripening of dry sausages by reaction between residual nitrite and amines formed during the fermentation process.

Animals↗
PubMed1998

Measurement of antibacterial activities of T-2 toxin, deoxynivalenol, ochratoxin A, aflatoxin B1 and fumonisin B1 using microtitration tray-based turbidimetric techniques.

Various mycotoxins were tested for their antibacterial activity by evaluating growth delays using a fully automated microturbidmetric method. Ten different strains of the genera Escherichia, Streptococcus, Staphylococcus, Yersinia, Salmonella, Erysipelothrix and Lactobacillus were used as test micro-organisms. T-2 toxin, deoxynivalenol (DON), ochratoxin A (OTA), aflatoxin B1 (AFB1) and fumonisin B1 (FB1) were used as representative mycotoxins. The inhibitory effect in vitro was defined as the difference between the growth rate without mycotoxins and the growth rate in the presence of a mycotoxin. Among the tested strains, Streptococcus agalactiae was found to be sensitive to all the toxins, with the exception of OTA. T-2 toxin and FB1 were the most effective in slowing down the growth of Staphylococcus aureus. AFB1 affected the growth of Yersinia enterocolitica. The growth rate of Escherichia coli and Salmonella infantis was decreased by FB1. Among the bacterial strains used in this study, only the growth of Erysipelothrix rhusiopathiae was inhibited by OTA. Thus, using appropriate tester strains it should be possible to set up a broad-range microtubidimetry assay for individual mycotoxin screening in vitro. We concluded that the microtitration technique provides a rapid, convenient and high-throughput capacity system to analyse bacteria-mycotoxin interactions.

Aflatoxin B1↗
PubMed1998

[Echography of the supraspinatus tendon: forced passive adduction maneuver].

INTRODUCTION: Imaging methods are essential for a correct diagnostic approach and treatment planning in patients with a painful shoulder. More than any other, the supraspinatus tendon is often involved in impingement syndrome and sonography (US) is now the procedure of choice for the first assessment of rotator cuff tears. We suggest a supraspinatus tendon passive stress maneuver drawing the tendon out from underneath the acromion and showing a longer portion of the tendon that would otherwise be masked by the acromion. MATERIAL AND METHODS: Twenty normal subjects (10 men and 10 women, aged 20 to 46 years, mean age: 32 years) and two patients with shoulder pain underwent shoulder US with real time equipment and a 7.5 MHz linear array transducer. US images were acquired with the subjects allowed to rest with their arm in neutral position and during supraspinatus tendon passive adduction stress maneuver (with the arm first abducted by placing a plastic cylinder device under the armpit, then submitted to passive forced adduction). All US scans were performed along the longitudinal axis of the tendon. The length of the supraspinatus tendon was measured from its insertion on the greater tuberosity of the humerus to the lateral edge of the acromion. Measurements were made in neutral position and during the stress maneuver and, for each subject, the increased length of the displayed portion was obtained as the difference between the two measurements. RESULTS AND CONCLUSIONS: In neutral position at rest, the displayed portion of the supraspinatus tendon was 21 mm long on the average (range: 11 to 31 mm). The average increase, namely the tendon portion recovered from the acromial acoustic shadow, was 4.5 mm (range: 2 to 10 mm). In two patients the stress maneuver permitted better visualization of tendon tear, which finding was confirmed at MRI. The results of our study so far seem to suggest that the passive adduction stress maneuver permits to visualize a longer portion of the supraspinatus tendon without affecting its anatomical alignment and could thus be useful in US studies of the rotator cuff.

Adult↗
PubMed1998

[The initial (I and II) and advanced (III and IV) stages of juvenile patellar chondromalacia. Its diagnosis by magnetic resonance using a 1.5-T magnet with FLASH sequences].

PURPOSE: Juvenile patellar chondromalacia is a common orthopedic disorder which can mimic other conditions; early diagnosis is mandatory to prevent its evolution into osteoarthrosis. In the early stages of patellar chondromalacia (I and II), the lesions originate in the deep cartilage layer and the joint surface is not affected. Arthroscopy can demonstrate joint surface changes only and give indirect information about deeper lesions. We investigated the yield of 2D FLASH MRI with 30 degrees flip angle and a dedicated coil in the diagnosis of patellar chondromalacia, especially in its early stages. MATERIAL AND METHODS: Eighteen patients (mean age: 21 years) with clinically suspected patellar chondromalacia were examined with MRI; 13 of them were also submitted to arthroscopy. A 1.5 T unit with a transmit-and-receive extremity coil was used. We acquired T1 SE sequences (TR/TE: 500-700/15/20) and 2D T2* FLASH sequence (TR/TE/FA: 500-800/18/30 degrees). The field of view was 160-180 mm and the matrix 192 x 256, with 2-3 NEX. The images were obtained on the axial plane. The lesions were classified in 4 stages according to Shahriaree classification. RESULTS: Agreement between MR and arthroscopic findings was good in both early and advanced lesions in 12/13 cases. Early lesions appeared as hyperintense focal thickening of the hyaline cartilage (stage I) or as small cystic lesions within the cartilage and no articular surface involvement (stage II). The medial patellar facet was the most frequent site. Advanced lesions appeared as articular surface ulcerations, thinning and cartilage hypointensity (stage III); stage IV lesions presented as complete erosions of the hyaline cartilage and hypointense underlying bone. CONCLUSIONS: 2D FLASH MRI with 30 degrees flip angle can show the differences in water content in the cartilage and thus permit to detect early chondromalacia lesions in the deep cartilage.

Adolescent↗
PubMed1997

Early postoperative MRI findings following surgery for herniated lumbar disc. Part II: A gadolinium-enhanced study.

The aim of our study was to evaluate the contrast-enhanced MR imaging (MRI) findings, in the early postoperative period, in unselected patients undergoing lumbar microdiscectomy (15/16 had total resolution of their symptoms). Contrast-enhanced imaging studies were performed, in all 16 patients of our series, before surgery, and at the third postoperative day and, two months after surgery. Postoperative paraspinal muscles enhancement was present in all patients. In the postoperative period, nerve root enhancement was present in 5/16 patients at the early survey and persisted in one after two months. A pseudohernia depicted as epidural intermediate signal intensity tissue, was seen in 13 patients at the third day MRI, and only in eight after two months. This pseudohernia enhanced peripherally in 8/13 patients and enhanced homogeneously in the remaining five at the first postsurgical examination; in the late MRI the peripheral enhancement was appreciable in only two patients while a homogeneous enhancement was observed in six. Clinical symptoms resolved completely in 14/16 patients on clinical evaluation at the third postoperative day, while the remaining two patients showed residual symptoms and signs of radicular compression. At the early MRI these two patients showed intradural nerve root enhancement. Two months later, one patient did not show the previously described nerve root enhancement and improved clinically, while the other had a positive Straight Leg Raising Sign with persistent intradural nerve root enhancement. In conclusion, no correlation between clinical course and contrast-enhancement of pseudohernia and extradural nerve root was appreciable, although intradural nerve root enhancement seems to represent a clinically relevant finding.

Adult↗
PubMed1997

Early postoperative MRI findings following surgery for herniated lumbar disc.

MRI is routinely used in the evaluation and management of patients with failed back surgery syndrome (FBSS). However, its value is unclear in the early detection of signs that can negatively affect that later course of surgical cases. The purpose of the present study is to describe the MR images of early postoperative MRI at 3 days in 30 unselected patients who underwent lumbar microdiscectomy, and to correlate the findings with follow up MRI at 8 weeks and with final outcome. The findings are correlated with literature data. Early postoperative MRI findings were consisting of pseudohernia in 24 patients (80%), annular rent in 23 patients (80%), and other non-specific postoperative findings. On the late MRI the pseudohernia persisted in 12 patients (50%), the annular rent in 4 patients (15%) and asymptomatic pseudo-spondylodiscitis was apparent in 3 patients (10%) as was a case of true spondylodiscitis. Therefore, early postoperative findings have limited value in the management of patients after surgery for lumbar disc herniation, since the images were not correlated with the immediate clinical course after surgery nor with the late radiological and clinical outcome. The evident imaging changes in the early postoperative period after lumbar disc surgery limit the accuracy of the interpretation of MRI examinations.

Discitis↗
PubMed1997

Brain stem compression secondary to adipose graft prolapse after transpetrosal approach: case report.

A case of fat graft prolapse into the prepontine cistern with clinical deterioration is presented. The patient had undergone a transpetrosal approach for a very large craniopharyngioma and had autologous thigh fat strips to obliterate the mastoid cavity; postoperatively she suffered an important deterioration from adipose graft prolapse. Clinical presentation, MRI findings, treatment, and avoidance of this complication are discussed.

Adipose Tissue↗
PubMed1997

T-2 toxin-induced DNA damage in mouse livers: the effect of pretreatment with coenzyme Q10 and alpha-tocopherol.

Active oxygen species are reported to cause organ damage. This study was therefore designed to determine whether oxidative stress contributed to the initiation or progression of hepatic DNA damage produced by T-2 toxin. The aim of the study was also to investigate the behaviour of the antioxidants coenzyme Q10 (CoQ10), and alpha-tocopherol (vitamin E) against DNA damage in the livers of mice fed T-2 toxin. Treatment of fasted mice with a single dose of T-2 toxin (1.8 or 2.8 mg/kg body weight) by oral gavage led to 76% hepatic DNA fragmentation. T-2 toxin also decreased hepatic glutathione (GSH) levels markedly. Pretreatment with CoQ10 (6 mg/kg) together with alpha tocopherol (6 mg/kg) decreased DNA damage. The CoQ10 and vitamin E showed some protection against toxic cell death and glutathione depletion caused by T-2 toxin. Oxidative damage caused by T-2 toxin may be one of the underlying mechanisms for T-2 toxin-induced cell injury and DNA damage, which eventually lead to tumourigenesis.

Animals↗
PubMed1997

Multiple organ failure following zymosan-induced peritonitis is mediated by nitric oxide.

In the present study we tested the hypothesis that nitric oxide may play a role in the pathogenesis of multiple organ failure induced by peritoneal injection of zymosan in the rat. A severe inflammatory response characterized by peritoneal exudation, high plasma and peritoneal levels of nitrate/ nitrite (breakdown products of nitric oxide), prostaglandin E2 and leukocyte infiltration into peritoneal exudate was induced by zymosan administration. This inflammatory process started within 3 h of administration and onset occurred at 18 h, coinciding with damage of lung, small intestine and liver, as assessed by histological examination and by increase of myeloperoxidase activity, indicative of neutrophil infiltration. Furthermore, at 18 h after zymosan-induced peritonitis, expression of inducible nitric oxide synthase enzyme was found mainly in the macrophages of inflamed lungs. Subcutaneously administration of a nonisoform selective nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester, reduced formation of peritoneal exudate fluid, blocked plasma and peritoneal nitrate/nitrite accumulation, and attenuated the elevated release of peritoneal prostaglandin E2. In addition, nitric oxide synthase inhibition was effective in preventing the development of organ failure since tissue injury and neutrophil infiltration, by myeloperoxidase evaluation, was reduced in lung, small intestine, and liver. In conclusion, major findings of our study are that nitric oxide exerts a proinflammatory role in the development of multiple organ failure and nitric oxide synthase inhibition is an effective antiinflammatory therapeutic tool, since inhibits not only nitric oxide but also prostaglandin production and cellular infiltration in inflamed organs.

Acute Disease↗
PubMed1997

Transforming growth factor-beta expression in mucosal biopsies in asthma and chronic bronchitis.

We assessed whether transforming growth factor-beta (TGF-beta), a fibrogenic growth factor, may be involved in remodeling of asthma and chronic bronchitis; its expression was compared with that of epidermal growth factor (EGF) and granulocyte macrophage colony-stimulating factor (GM-CSF) in bronchial mucosal biopsies from 13 normal subjects, 24 asthmatics, and 19 patients with chronic bronchitis. TGF-beta immunoreactivity was highly increased in epithelium and submucosa of those with bronchitis and to a lesser extent in asthmatics. By comparison, with normal subjects, EGF immunoreactivity was significantly increased in the epithelium of bronchitic subjects and submucosa of asthmatics, and, GM-CSF immunoreactivity was increased in both epithelial and submucosal cells of asthmatics and to a lesser extent in submucosa of bronchitics. A significant correlation was found between the number of epithelial or submucosal cells expressing TGF-beta in both asthma and chronic bronchitis and basement membrane thickness and fibroblast number. No such correlation was found for EGF or GM-CSF. in situ hybridization for TGF-beta 1 mRNA confirmed the results obtained by immunohistochemistry. By combining in situ hybridization and immunohistochemistry, it was found that eosinophils and fibroblasts were synthetizing TGF-beta in asthma and bronchitis. These data suggest that TGF-beta, but not EGF or GM-CSF, is involved in airways remodeling in asthma and chronic bronchitis.

Adolescent↗
PubMed1997

[The echographic assessment of traumatic rib lesions].

INTRODUCTION: Conventional frontal radiography is mandatory in trauma patients and usually sufficient to detect rib fractures, even though the alignment of bone fragments or projection difficulties may sometimes hinder their depiction. Therefore, there exists moderate disagreement between clinically suspected rib fractures and radiographic findings. MATERIALS AND METHODS: We report our personal experience with US in the detection of rib conditions (fractures and bruises), missed at preliminary radiography. Five symptomatic patients with suspected rib fractures underwent radiographic and US studies. All patients were examined with a real time unit (RT 2800, GE Medical Systems, Milwaukee, USA) with a 7.5 MHz linear probe. RESULTS AND CONCLUSION: US demonstrated rib fractures in 4 patients with negative radiographic findings and a parosteal hematoma in one patient. We conclude that US can detect the rib fractures missed at conventional radiography and show rib cartilage conditions, costochondral dislocations and parosteal hematomas. Therefore we suggest the routine use of this technique in all chest trauma patients, as a useful complement to frontal radiographs, for both management and forensic purposes.

Adult↗
PubMed1996

Prevention of anterior cruciate ligament injuries in soccer. A prospective controlled study of proprioceptive training.

Proprioceptive training has been shown to reduce the incidence of ankle sprains in different sports. It can also improve rehabilitation after anterior cruciate ligament (ACL) injuries whether treated operatively or nonoperatively. Since ACL injuries lead to long absence from sports and are one of the main causes of permanent sports disability, it is essential to try to prevent them. In a prospective controlled study of 600 soccer players in 40 semiprofessional or amateur teams, we studied the possible preventive effect of a gradually increasing proprioceptive training on four different types of wobble-boards during three soccer seasons. Three hundred players were instructed to train 20 min per day with 5 different phases of increasing difficulty. The first phase consisted of balance training without any balance board; phase 2 of training on a rectangular balance board; phase 3 of training on a round board; phase 4 of training on a combined round and rectangular board; phase 5 of training on a so-called BABS board. A control group of 300 players from other, comparable teams trained "normally" and received no special balance training. Both groups were observed for three whole soccer seasons, and possible ACL lesions were diagnosed by clinical examination, KT-1000 measurements, magnetic resonance imaging or computed tomography, and arthroscopy. We found an incidence of 1.15 ACL injuries per team per year in the proprioceptively trained group (P < 0.001). Proprioceptive training can thus significantly reduce the incidence of ACL injuries in soccer players.

Anterior Cruciate Ligament Injuries↗
PubMed1996

An arthroscopic and electromyographic study of painful shoulders in elite gymnasts.

Shoulder problems are common in overhead sports like baseball, basketball and volleyball. Although gymnastics also includes overhead activities, there are few reports about shoulder problems in this sports activity. During the time period 1992-1995 we treated five young competitive gymnasts for shoulder pain. Arthroscopy revealed that they were all suffering from SLAP lesions or other labral pathology, although they had never dislocated their shoulders. These injuries have not been described earlier in connection with gymnastics. In a survey of 13 gymnasts in an elite club, we found that six (46%) complained about shoulder pain. Since four of these athletes explained that their shoulder pain started acutely during ring exercises in suspension while one suffered a slower onset with pain also during parallel bar exercises, we undertook an electromyographic study of the shoulder musculature of three normal elite gymnasts during exercises on the parallel bars and rings. We found that during the ring exercises in suspension there was a "critical phase" during which the muscle activity around the shoulder was very low, leading to great articular stresses. This might explain the occurrence of labral lesions like the SLAP lesions in this type of athlete. If shoulder pain in elite gymnasts does not respond to rest and physical therapy over 2-3 months, a shoulder arthroscopy should be considered.

Adolescent↗
PubMed1996

Excessive stimulation of serotonin2 (5-HT2) receptors during late development of chicken embryos causes decreased embryonic motility, interferes with hatching, and induces herniated umbilici.

The existence and functional significance of 5-HT2 receptors in chicken embryos was studied by injecting the selective agonist dimethoxyiodophenylaminopropane (DOI), alone or in conjunction with the selective 5-HT2 antagonist ritanserin (RIT), into domestic chicken eggs with embryos of varying ages. DOI caused dose-dependent reductions in hatchability and herniated umbilici in hatchlings. These effects were observed after injection early, mid, or late during embryonic development, with evidence of the toxic effects of DOI being greater in older embryos, probably due to 5-HT2 receptor activation late in development, even after injecting DOI as early as on day 3 of embryogenesis. This is based upon the fact that embryos in eggs injected with DOI early continued to develop apparently normally, failing to hatch, often after pipping their shells. Additionally, those that hatched often did so with herniated umbilici, as did late-exposed embryos, indicating that DOI's effects upon this organ were most likely mediated during the prehatching period (i.e., days 18-20). The agonist's selectivity was confirmed by the capacity of RIT to dose dependently block both of these toxic effects of DOI. Reduced embryonic motility monitored on day 19, after injection of DOI on the evening of day 18, suggests that excessive activation of 5-HT2 receptors late during development of this species interferes with some normal embryonic behaviors and physiological changes necessary for inducing and/or maintaining the hatching process.

Animals↗
PubMed1996

Oxygen affinity and Bohr effect responses to 2,3-diphosphoglycerate in equine and human blood.

The dependence of blood oxygen affinity and the Bohr effect on the concentration of 2,3-diphosphoglycerate (DPG) in erythrocytes was investigated in 24 trotter horses and 24 healthy men. The oxygen tension at half saturation and standard conditions (P50st at pH 7.4, PCO2(40) mmHg and 37 degrees C) and the carbon dioxide or fixed-acid-induced Bohr effect (dlogP50/dpH) were determined. Samples of fresh blood and blood depleted of or enriched with DPG were studied. In the absence of measurable DPG, the equine and human blood had similar mean (SD) values of P50st (16.6 [0.6] and 16.2 [0.7] mmHg, respectively). In both species these values increased with increasing DPG, but the response of equine blood was significantly lower, at least up to physiological values (P50st = 24.6 [0.6] and 26.2 [0.7]) mmHg; DPG = 14([1.8] and 12.8 [1.2] mumol gHb-1, respectively, in fresh blood). For concentrations above 20 to 25 mumol gHb-1 of DPG the difference between the values of P50st in the two species tended to decrease because the response in human blood reached a plateau. The interactions between the Bohr effect and the concentration of DPG showed that in the horses, as in the men, the level of DPG played an important role in governing the relative magnitude of carbon dioxide and fixed acid factors. The difference between them, which is associated with the oxylabile carbamino binding, was greatest in DPG-depleted blood, but whereas in the men the difference was suppressed by an above normal DPG concentration, in the horses it was still measurable.

2,3-Diphosphoglycerate↗
PubMed1996

Fronto-orbito zygomatic approach: a technical modification.

The fronto-orbito zygomatic approach is part of the surgical armamentarium of modern skull base surgery. As described in the literature, it requires costly technological tools such as powerful drills and saws, to be performed. In the present communication we describe a technical modification that allows the zygoma to be elevated "en bloc" together with the fronto-orbital bone flap by means of appropriate use of the Gigli's saw. Using this technique, adequate replacement of the craniotomy flap requires only two silk sutures. This technical modification, which was already successfully used in over 20 cases, would also allow this useful approach to be performed in those neurosurgical environments where modern costly technology for cranial base surgery is not available.

Journal Article↗