Validation and comparison of analytical methods for the determination of histamine in tuna fish samples.

Histamine is a degradation product of the bacterial decarboxylation of the amino acid histidine, which is present in large amounts in fish tissues of the Clupeidae and Scombridae families and its presence is an indicator of good manufacturing practices and of the state of preservation of some food. A capillary electrophoresis and high-performance liquid chromatography method with diode arrays detection (HPLC-DAD) were compared and validated: no laborious pre-treatment, no clean up and no derivatization was necessary. In both techniques the correlation coefficient exceeded 0.999 for all the analyses carried out during validation. The limit of detection and the limit of quantitation are 1 and 2 mg/kg, respectively, for high-performance liquid chromatography and 0.5 and 1 mg/kg, respectively, for capillary electrophoresis. Good recoveries were observed for the histamine under investigation at all spiking levels and average recoveries were higher than 92% with the relative standard deviation less than 4% for high-performance liquid chromatography and average recoveries were higher than 85% with the relative standard deviation less than 3% for capillary electrophoresis.

Validation of a high-performance liquid chromatography method for the determination of oxytetracycline, tetracycline, chlortetracycline and doxycycline in bovine milk and muscle.

High-performance liquid chromatography with diode-array detection (HPLC-DAD) was optimised and validated for the determination of tetracyclines in bovine milk and tissues. Milk and tissue samples were extracted and purified using a solid-phase extraction HLB Oasis cartridge and analysed using HPLC-DAD set at 365 nm. The analyses were carried out using the mobile phase of 0.01 M oxalic acid-acetonitrile-methanol (60:25:15, v/v/v) on a C8 column (250 x 4.6 mm I.D., 5 microm). Recoveries of tetracyclines from spiked samples at the three concentrations (0.5, 1 and 1.5) of the maximum residues limits (corresponding to 100 microg/kg for milk and the muscle) were higher than 81.1% in milk and 83.2% in muscle. The method was successfully validated for bovine milk and muscle in compliance with requirements set by draft SANCO/ 1805/ 2000 European Decision. The decision limit (CCalpha) was in the range 113.2-127.2 microg/kg and 107.7-129.9 micro/kg for all compounds in milk and muscle, respectively. The detection capability (CCbeta) was in the range 117.2-131.3 microg/kg and 114.9-133.1 microg/kg for all compounds in milk and muscle, respectively.

Sulfamethazine, sulfothiazole and albendazole residue dosage in food products determined by liquid chromatography/tandem mass spectrometry.

There is a growing demand for analytical techniques for the detection of a wide variety of residues from synthetic molecules in matrices such as soil, water, air and food. These techniques have to meet the requirements of speed and sensitivity as well as the ability to handle any matrix with minimal sample clean-up. Features of mass spectrometry combined with liquid chromatography can fulfill these requirements as is shown by this work which reports the use of ion spray ionization coupled with tandem mass spectrometry for the detection of some drug residues. In particular, the direct use of existing LC methods, originally conceived for use with some other sort of detector, is demonstrated.

[Mallory-Weiss syndrome. Clinical cases and review of the literature]. / La sindrome di Mallory-Weiss. Casi clinici e revisione della letteratura.

Once considered rare, Mallory-Weiss syndrome is today more frequently reported due to the introduction of endoscopy which reveals this syndrome in up to 15% of hemorrhages of the upper digestive tract. The etiopathogenesis is not limited to the three factors reported by Mallory and Weiss in 1929: vomit, alcohol and hematemesis. An important role is also played by ASA and the like. This syndrome is also frequently associated with hiatus hernia in which it appears to be a complication since the lesion seems to be caused by the difference between intragastric (above all in the pocket of the hiatus hernia) and intrathoracic transmural pressure. Every increase in the pressure gradient at this level appears to cause fissuration at the cardioesophageal junction. Even endoscopy using rigid instruments and unsufflation may provoke the onset. Anamnesis and an objective examination, common to other pathologies, are not of great value to diagnosis. Radiology also contributes little, unless an arteriography is performed within the context of a highly selective angiography. Endoscopy is the prime method of diagnosis and, in addition to revealing the site and extent of hemorrhage, may be used to achieve hemostasis. Preendoscopic hemostasis currently uses a wide range of methods ranging from sclerotherapy to the injection of drugs or chemical substances, such as ethanol, adrenalin and thrombin; monopolar and bipolar electrocoagulation, thermal probe, hemoclips and Nd:YAG laser are also used. According to the majority of authors, the course of the syndrome is benign unless there are complications such as mediastinitis, pneumonia ab ingestis or hepatic insufficiency. The degree of bleeding is also decisive and the number of blood units transfused is of particular importance in determining the prognosis. The authors report a 10-year survival rate of approximately 70%.

[Lipoma of the small intestine as a rare cause of intestinal occlusion]. / Lipoma del tenue come rara causa di occlusione intestinale.

Lipoma is a benign tumour of mesenchymal origin which is not frequently localized in the gastroenteric tract; in anatomopathological statistics it is less rare: this is due to the fact that it rarely reaches dimensions which warrant surgical treatment. It is usually either an occasional finding during the course of laparotomy due to other motives or is the cause of complications, as in the present case of intestinal occlusion due to ileocolic invagination, resulting in emergency surgery. As a cause of occlusion tumours of the small bowel are second in terms of incidence to adhesive factors, volvuli and hernias. Invaginations account for 2/3 of small bowel occlusions caused by up to 80% of tumours: the lipoma is the most frequent benign tumour to cause invagination in its submucous polypoid and more or less scissile form. Symptoms are not specific and this causes a delay in diagnosis. Patients are often young subjects with a history of recurrent abdominal colic and sensitivity to anti-spastic drugs so much so that in the past they were diagnosed as "chronic colic" sufferers. Sometimes the only symptom is dyspepsia, or nausea and vomiting, or occasionally abdominal distension with constipation or attacks of diarrhoea. Radiology is not of great value in the diagnosis except for indicating the possible need for emergency surgery. There are no radiological tests, with or without contrast mediums, echography, CAT or MNR which can diagnose this pathology. The decision to operate is usually triggered by the presence of a complication, but perioperative extemporary histological tests are advisable for a correct surgical approach: if the form is scissile, segmentary resection of the small bowel is necessary.(ABSTRACT TRUNCATED AT 250 WORDS)

[Splenic rupture in chronic pancreatitis. A clinical case. Observations]. / Rottura di milza in corso di pancreatite cronica. Caso clinico. Considerazioni.

The paper reports a case of splenic rupture during the course of chronic pancreatitis, an event rarely reported in the literature. The anatomical arrangement of organs and peripancreatic vessels is a predisposing factor for this complication. There are essentially three different but correlated pathogenetic hypotheses. The first refers to thrombosis of the splenic vein with portal hypertension documented by some researchers even in angiographical terms: during the course of chronic pancreatitis the spleen is sometimes palpable. Thrombosis and/or vascular compression make the spleen more fragile and its rupture more likely: this is particularly true during the course of calcific chronic pancreatitis and cases involving the tail. An enzymatic factor may also be responsible and this appears more clearly in pancreatitis with pseudocysts. In this case it is the direct action of pancreatic enzymes on the ileum or splenic parenchyma, which may also affect all organs surrounding the pancreas, which leads to hemorrhage or hematoma. Sometimes the cause of bleeding is a pseudoaneurysm of the splenic artery which is eroded by the contents of the pseudocysts themselves. There is also a mechanical hypothesis which some authors consider the sole possibility: in chronic pancreatitis the splenic compartment presents severe perisplenitis which fixes the spleen making it more vulnerable and even a mini-trauma will cause rupture. The patient is almost always an emaciated young alcoholic suffering from chronic pancreatic pathology.(ABSTRACT TRUNCATED AT 250 WORDS)

[Symmetry, ptosis and a new infra-mammary border in the reconstruction of the breast with a tissue expander]. / Simmetria, ptosi e nuovo solco inframammario nella ricostruzione della mammella con tissue-expander.

The aim of this procedure is to obtain a permanent prosthesis (after mastectomy and the insertion of a tissue expander) that is similar to the contralateral breast in volume, morphology and inframammary border. The technique involves aspiration of the tissue expander fluid until the desired volume is obtained and the measurement of the fluid which indicates the volume of the prosthesis to be inserted. Given the satisfactory results obtained, the intention is to continue adopting this procedure.

[A case of retroperitoneal leiomyosarcoma. Considerations]. / Su un caso di leiomiosarcoma retroperitoneale. Considerazioni.

A case of retroperitoneal leiomyosarcoma is reported. The retroperitoneal localization is quite unusual and early diagnosis is really difficult. Only operation can offer any chance for cure of this neoplasm and radiotherapy and chemotherapy can be very useful. Tumor size and location are the major prognostic factors.

T cell nature of some lymphokine-activated killer (LAK) cells. Frequency analysis of LAK precursors within human T cell populations and clonal analysis of LAK effector cells.

The cell lineage of the lymphokine-activated killer (LAK) cells has been reinvestigated. Both T and non-T cells, isolated on the basis of rosette formation with sheep erythrocytes (E), generated LAK activity after 3-4 days of culture in recombinant interleukin 2 (rIL 2) in 8 different individuals tested. By applying a microculture technique which allows clonal expansion of virtually all E rosetting T cells, we further analyzed the frequency of clonogenic LAK precursors within T cell populations. Approximately 1 of 25 T cells was found to be a LAK precursor. Moreover, microcultures with LAK activity lysed both the natural killer-sensitive K562 cell line and the P815 target cells in the presence of phytohemagglutinin (PHA). Since cytolytic T lymphocytes capable of lysing P815 cells in the PHA-dependent assay were approximately 1/3, it is evident that only a minor subset of cytolytic T lymphocyte precursors can acquire LAK activity even in the presence of large amounts of IL 2. Several LAK clones obtained by limiting dilution were further expanded and analyzed for their phenotypic and functional properties. Twelve out of 14 clones analyzed expressed the T3+ T11+ phenotype whereas 2 were T3- T11+. All had maintained their original cytolytic pattern; moreover, the large majority of the T3+ clones produced IL 2 and interferon-gamma following PHA stimulation.

Both the precursors and the effectors of human lymphokine-activated killer (LAK) cells may belong to T lymphocytes.

The present experiments were designed to perform a further investigation of the cell lineage of lymphokine-activated killer (LAK) cells. In the presence of adherent cells both T and not-T cells, separated on the basis of rosette formation with sheep erythrocytes (E rosettes), generated LAK activity after short-term culture in recombinant interleukin-2 in 5 different individuals tested. Since at the termination of the culture more than 98% of cells were T11-positive, it is evident that both LAK precursor and effector cells may belong to the T cell lineage. By applying a culture technique which allows the clonal expansion of virtually all T cells, we further selected and analyzed T cell clones with LAK activity. Under the culture conditions used, LAK clones represented approximately 4% of all proliferating clones. All had cytolytic activity against K562 target cells as well and also released large amounts of gamma-interferon following phytohemagglutinin stimulation.

Heterogeneity of B cell growth factor (BCGF)-producing T cells in humans. Clonal analysis of BCGF-producing cells within T4+ and T8+ subsets and evidence for the involvement of different growth factors in different BCGF assays.

Human peripheral blood T cells were cloned under conditions allowing the clonal expansion of virtually all T cells. Clones derived from T4+ or T4- (T8+) subsets were screened for their ability to induce B cell proliferation either in the Staphylococcus aureus Cowan-I (SAC)-driven assay or in the costimulation assay based on the use of anti-mu antibodies. BCGF activity in the SAC- and in the anti-mu-driven system was displayed by 13% and 15% T8+ clones, respectively, while 74% and 79% T4+ clones had BCGF activity in the same assay. SN of clones with BCGF activity were further screened for their susceptibility to the inhibition by CM 269 (anti-IL-2 receptor) monoclonal antibody. All clones were inhibited in the SAC assay, whereas several clones were partially or totally resistant to inhibition in the anti-mu assay. Nine of such non-inhibited clones were further analyzed for their ability to produce gamma-IFN (known to act as a BCGF) and IL-2: six of them were found to produce gamma-IFN, while none produced any detectable IL-2 activity.

O- and N-alkylation with "Meerwein's reagent": the unusual behaviour of two lactams.

Usually tertiary oxonium salts are excellent O-alkylating agents of lactams; in some cases indiscriminate O- and N-alkylations have been described. In this paper the particular behaviour towards Meerwein's reagent of two isomers with a lactamic structure is pointed out: in one case the usual O-alkylation occurs, in the other N-alkylation is the only reaction that takes place.