Progenitor cell recruitment during individualized high-flow, very-large-volume apheresis for autologous transplantation improves collection efficiency

BACKGROUND

Individual adaptation of processed patient's blood volume (PBV) should reduce number and/or duration of autologous peripheral blood progenitor cell (PBPC) collections.

STUDY DESIGN AND METHODS

The durations of leukapheresis procedures were adapted by means of an interim analysis of harvested CD34+ cells to obtain the intended yield of CD34+ within as few and/or short as possible leukapheresis procedures. Absolute efficiency (AE; CD34+/kg body weight) and relative efficiency (RE; total CD34+ yield of single apheresis/total number of preapheresis CD34+) were calculated, assuming an intraapheresis recruitment if RE was greater than 1, and a yield prediction models for adults was generated.

RESULTS

A total of 196 adults required a total of 266 PBPC collections. The median AE was 7.99 x 10(6), and the median RE was 1.76. The prediction model for AE showed a satisfactory predictive value for preapheresis CD34+ only. The prediction model for RE also showed a low predictive value (R2 = 0.36). Twenty-eight children underwent 44 PBPC collections. The median AE was 12.13 x 10(6), and the median RE was 1.62. Major complications comprised bleeding episodes related to central venous catheters (n = 4) and severe thrombocytopenia of less than 10 x 10(9) per L (n = 16).

CONCLUSION

A CD34+ interim analysis is a suitable tool for individual adaptation of the duration of leukapheresis. During leukapheresis, a substantial recruitment of CD34+ was observed, resulting in a RE of greater than 1 in more than 75 percent of patients. The upper limit of processed PBV showing an intraapheresis CD34+ recruitment is higher than in a standard large-volume leukapheresis. Therefore, a reduction of individually needed PBPC collections by means of a further escalation of the processed PBV seems possible.

Molecular characterization of human adenoviruses isolated in Italy

There is little information on the epidemiology of Human Adenoviruses (HAdVs) in Italy. In this study, 103 HAdV isolates, collected by the A. Gemelli Hospital (Catholic University Medical School of Rome, Italy) between 1987 and 2005, were genotyped by sequencing and phylogenetic analysis on a partial hexon gene region. Nine different serotypes belonging to all six HAdV species were identified. Serotype 2 was the most frequent (53.4%), followed by serotype 1 (15.53%) and serotype 41 (9.7%). Partial-hexon-based identification was confirmed as an effective tool for studying the molecular epidemiology of HAdVs.

Treatment of thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP), characterized by thrombocytopenia and microangiopathic haemolytic anaemia, was almost universally fatal until the introduction of plasma exchange (PE) therapy in the 1970s. Based on clinical studies, daily PE has become the first-choice therapy since 1991. Recent findings may explain its effectiveness, which may include, in particular, the removal of anti-ADAMTS13 autoantibodies and unusually large von Willebrand factor multimers and/or supply of ADAMTS13 in acquired idiopathic or congenital TTP. Based on currently available data, the favoured PE regimen is daily PE [involving replacement of 1-1.5 times the patient's plasma volume with fresh-frozen plasma (FFP)] until remission. Adverse events of treatment are mainly related to central venous catheters. The potential reduction of plasma related side-effects, such as transfusion-related acute lung injury (TRALI) or febrile transfusion reactions by use of solvent-detergent treated (S/D) plasma instead of FFP is not established by controlled clinical studies. Uncontrolled clinical observations and the hypothesis of an autoimmune process in a significant part of the patients with acquired idiopathic TTP suggest a beneficial effect of adjunctive therapy with corticosteroids. Other immunosuppressive treatments are not tested in controlled trials and should be reserved for refractory or relapsing disease. There is no convincing evidence for the use of antiplatelet agents. Supportive treatment with transfusion of red blood cells or platelets has to be evaluated on a clinical basis, but the transfusion trigger for platelets should be very restrictive. Further controlled, prospective studies should consider the different pathophysiological features of thrombotic microangiopathies, address the prognostic significance of ADAMTS13 and explore alternative exchange fluids to FFP, the role of immunosuppressive therapies and of new plasma saving approaches as recombinant ADAMTS13 and protein A immunoadsorption.

Diffusion dynamics during the nucleation and growth of Ge/Si nanostructures on Si(111)

We report a low energy electron microscopy study of the relation between self-organized Ge/Si(111)nanostructures and their local environment. By comparison with Monte Carlo simulations, three-dimensional islands are shown to display a substantial tendency towards self-ordering. This tendency may result from the diffusive nature of the nucleation processes. The size of individual nanostructures does not significantly correlate with the distance between neighboring islands. Thus energetic factors are thought to govern the competition among coexisting nanostructures to capture the deposited mass.

Chemical mapping of individual semiconductor nanostructures

We demonstrate experimentally the power of a novel analytical tool for X-ray spectromicroscopy. This provides a minimally intrusive elemental mapping of surfaces at the nanoscale and holds the promise of remarkable versatility. We have applied our procedure to the characterization of Ge(Si) islands on Si(111) substrates, with the aim of investigating the surface stoichiometry gradients and gaining insight into the intermixing dynamics. By identifying Si-richer edges with respect to the centers, we are able to associate alloying in these islands to surface transport processes.

Proteomic analysis of protein components in periodontal ligament fibroblasts

BACKGROUND

Characterization of periodontal ligament (PDL) fibroblast proteome is an important tool for understanding PDL physiology and regulation and for identifying disease-related protein markers. PDL fibroblast protein expression has been studied using immunological methods, although limited to previously identified proteins for which specific antibodies are available.

METHODS

We applied proteomic analysis coupled with mass spectrometry and database knowledge to human PDL fibroblasts.

RESULTS

We detected 900 spots and identified 117 protein spots originating in 74 different genes. In addition to scaffold cytoskeletal proteins, e.g., actin, tubulin, and vimentin, we identified proteins implicated with cellular motility and membrane trafficking, chaparonine, stress and folding proteins, metabolic enzymes, proteins associated with detoxification and membrane activity, biodegradative metabolism, translation and transduction, extracellular proteins, and cell cycle regulation proteins.

CONCLUSIONS

Most of these identified proteins are closely related to the extensive PDL fibroblasts' functions and homeostasis. Our PDL fibroblast proteome map can serve as a reference map for future clinical studies as well as basic research.

Dopamine “Renal Dose” Versus Fenoldopam Mesylate to Prevent Ischemia-Reperfusion Injury in Renal Transplantation

Low dose of dopamine is commonly used after kidney transplantation as a reno-protective agent, although its benefits are controversial. Dopamine may increase renal blood flow, decrease resistive index (RI), and induce urine output in normal kidneys. Many authors hypothesized that the vasculature of a denervated renal transplant may not respond to dopamine in the same fashion as healthy native kidneys, which led us to find other drugs to attenuate the ischemia-reperfusion (I/R) injury. Fenoldopam is a selective dopamine1 (DA1) receptor agonist, most of the activity of which resides in the R-enantiomer, which also shows weaker alpha 2-adrenoceptor antagonist activities. Fenoldopam produces a vasidilatory effect in vascular beds that are rich in vascular DA1 receptors, producing increased renal blood flow at doses that do not affect blood pressure. In addition to its renal vasodilator activity, fenoldopam is natriuretic, possibly resulting from a direct effect of DA1 receptors on the proximal convoluted tubule. In animals with spontaneous or drug-induced renal failure, fenoldopam improves renal function. The aim of this study was to investigate the possible effects of fenoldopan mesylate in recent kidney transplants. Creatinine, blood urea nitrogen, urine output, and renal vascular resistive index (IR) were measured using Doppler ultrasound. Two groups of patients with no statistical differences in demographic data were treated with dopamine or fenoldopan, showing no significant difference but a trend favoring the fenoldopan group.

Oxaliplatin-induced immune pancytopenia

BACKGROUND

Oxaliplatin, a third-generation platinum compound, has been implicated in isolated cases of immune hemolytic anemia and/or immune thrombocytopenia. The first case of severe immune pancytopenia related to oxaliplatin is described.

PATIENT AND METHODS

A 79-year-old woman with colorectal cancer was initially treated with 5-fluorouracil and she later received oxaliplatin and leucovorin every 2 to 4 weeks. During the 15th and 17th cycles of chemotherapy she developed thrombocytopenia, hemolysis, and neutropenia. No problems occurred during the 16th cycle without oxaliplatin. Serologic testing including detection of drug-dependent antibodies and autoantibodies was performed with standard techniques.

RESULTS

Serologic findings included a positive immunoglobulin G direct antiglobulin test; nonreactive red blood cell (RBC) eluates; platelet (PLT)-bound antibodies to glycophorin (GP) IIb-IIIa, GPIb-IX, and GPIa-IIa; and oxaliplatin-dependent antibodies to PLTs, RBCs, and neutrophils.

CONCLUSION

Oxaliplatin may lead to the production of ddabs to RBCs, PLTs, and neutrophils. Thus the risk of immune cytopenias should always be considered in patients treated with oxaliplatin.

Molecular and serologic tracing of a transfusion-transmitted hepatitis A virus

BACKGROUND

The transmission of hepatitis A virus (HAV) via blood transfusion has not been evidenced by molecular tracing so far.

CASE REPORT

A 33-year-old asymptomatic female volunteer made a whole-blood donation. Thirteen days later an acute HAV infection was diagnosed. Retrospectively, a high viral load was measured by quantitative reverse transcription polymerase chain reaction (RT-PCR) in the quarantine fresh-frozen plasma (1.4 x 10(6) geq/mL), whereas immunoglobulin M (IgM) and G (IgG)/IgM anti-HAV were not detectable and the alanine aminotransferase levels not elevated. The red blood cells have just been transfused on Day 14. The 63-year-old male recipient already was HAV seropositive. He did not develop clinical symptoms of HAV and anti-HAV IgM was not detected. Seventy-five days later, a 25-fold increase in the anti-HAV IgG/IgM titer was observed. Demonstrable HAV ribonucleic acid (RNA) in the recipient by means of RT-PCR on Day 6, but not on Days 1 and 75, suggests that a transient reinfection did occur. Analyzed sequences of the HAV RNA in the donor and recipient were identical.

CONCLUSION

For the first time, transfusion-transmitted HAV was evidenced by molecular and serologic tracing. The transmitted HAV can survive and replicate for a limited period despite the presence of anti-HAV IgG.

Plasma therapy in thrombotic thrombocytopenic purpura: review of the literature and the Bern experience in a subgroup of patients with severe acquired ADAMTS-13 deficiency

Based on clinical studies daily plasma exchange (PE) has become the first-choice therapy for thrombotic thrombocytopenic purpura (TTP) since 1991. Recent findings may explain its effectiveness, which particularly may include supply of ADAMTS-13 and removal of anti-ADAMTS-13 autoantibodies and unusually large von Willebrand factor (VWF) multimers. The most preferable PE regimens as well as replacement fluids are discussed and treatment-related adverse reactions are summarized. Proposals for a potential reduction of their frequency and for improvement of treatment efficiency are given. These suggestions are partially based on the experience of our institution in adult patients with severe ADAMTS-13 deficiency (<5% activity), and include (1) continuous calcium-gluconate infusion during PE in order to reduce citrate-related adverse reactions; (2) the evaluation of solvent/detergent-treated (S/D) plasma as replacement fluid in order to reduce adverse events due to fresh frozen plasma (FFP); (3) the evaluation of immunoadsorption in order to increase procedural efficiency in autoantibody removal; and (4) the substitution of ADAMTS-13 by means of recombinant drug instead of plasma.

Plasma adrenomedullin concentrations in patients with renovascular or malignant hypertension

AIM

The aim of the present study was to investigate the behaviour of plasma adrenomedullin (AM), a hypotensive peptide, in patients with malignant (MHT) and renovascular hypertension (RVH), 2 pathologic conditions in which renin-angiotensin system (RAS) is activated and to compare them with those in essential hypertensive patients (EHT) and normotensive subjects (NS).

METHODS

Three groups of hypertensive patients have been studied: group 1 (4 patients with MHT), group 2 (10 patients with RVH), group 3 (24 patients with EHT) and 21 patients NS were enrolled as controls. In all patients, 10 ml vein blood samples were collected and AM was measured with specific radioimmunoassay.

RESULTS

As expected, the plasma renin activity (PRA) levels in the RVH and MHT patients were significantly higher (p<0.0001) respect to NS and EHT. The mean plasma AM (+/-SD) concentrations in EHT (22.5+/-9.1 pg/ml) and RVH (46.8+/-19.4 pg/ml) were significantly (p<0.0001) higher than those in NS (13.7+/-6.1 pg/ml). The plasma AM concentrations were further elevated in MHT patients (107+/-12.3 pg/ml) and were significantly higher (p<0.0001) than those in EHT and RVH patients. In the MHT patients the elevated plasma AM levels, similarly to blood pressure and PRA values, declined after antihypertensive treatment (36.8+/-5.7 pg/ml; p<0.01).

CONCLUSION

In conclusion, the findings demonstrated that the plasma AM concentrations were increased in proportion to the severity of arterial hypertension. RAS was activated in patients with MHT and RVH suggesting that activation of this system may contribute to increased in the plasma levels of AM.

Interaction Between Natural Killer and Dendritic Cells: the Role of CD40, CD80 and Major Histocompatibility Complex Class I Molecules in Cytotoxicity Induction and Interferon-gamma Production

This study focuses on the differential role of CD40 and CD80 costimulatory molecules and major histocompatibility complex class I (MHC-I) antigens in the regulation of the interplay between dendritic cells (DCs) and interleukin (IL)-2-activated human natural killer (NK) lymphocytes. Our data indicate that CD40 and CD80 molecules might play a preferential role in the induction of cytotoxic function but not in the interferon-gamma(IFN-gamma) production by human IL-2-activated NK effectors in the presence of autologous and allogeneic DCs. In addition, a critical role of CD94-dependent MHC-I recognition in the regulation of both IFN-gamma production and target cell lysis was shown in the functional interaction between NK and DCs.

Splenectomy in relapsing and plasma-refractory acquired thrombotic thrombocytopenic purpura

BACKGROUND AND OBJECTIVES

Acquired thrombotic thrombocytopenic purpura (TTP) is often due to autoantibodies inhibiting ADAMTS-13 activity resulting in impaired processing of very large von Willebrand factor multimers. TTP usually presents with an acute onset and a fulminant, sometimes fatal course. With appropriate treatment including plasma exchange, and fresh frozen plasma replacement, often supplemented by immuno-suppressive therapy, the acute episode generally resolves within days to weeks.

DESIGN AND METHODS

We describe the clinical course of 3 patients with acquired TTP. One was refractory to PE, the other 2 relapsed after this treatment. All three were treated with splenectomy. ADAMTS-13 activity and inhibitor levels were monitored.

RESULTS

ADAMTS-13 activity was initially < 5% in all 3 patients. After splenectomy the inhibitor against ADAMTS-13 disappeared rapidly in 2 patients and there was full recovery of ADAMTS-13 activity in all 3 patients.

INTERPRETATION AND CONCLUSIONS

Splenectomy, by eliminating a source of pathogenic autoantibody production, can be a successful treatment for patients with relapsing or plasma-refractory acquired TTP due to autoantibody-mediated ADAMTS-13 deficiency.

Leptin as a novel therapeutic target for immune intervention

The recent cloning of the leptin (obese, ob) gene has determined fundamental insight into the understanding of the regulation of food intake, basal metabolism and reproductive function. Leptin, mainly secreted by adipocytes, belongs to the helical cytokine family and its plasma concentrations correlate with fat mass and respond to changes in energy balance. Initially, leptin was considered as an anti-obesity hormone, but experimental evidence has also shown pleiotropic effects of this molecule on hematopoiesis, angiogenesis, lymphoid organ homeostasis and T lymphocyte functions. More specifically, leptin links the pro-inflammatory T helper (Th)-1 immune response to the nutritional status and the energy balance. Indeed, decreased leptin concentrations during conditions of food deprivation lead to impaired immune capabilities. This review focuses on the potential therapeutic utilities for agents that manipulate the leptin-adipocyte axis and discusses novel strategies for an immune intervention in pathologic conditions.

Severity of human hypertension in relation to the age in which high blood pressure makes its presumptive appearance

PURPOSE

The present study investigates the properties of blood pressure (BP) circadian rhythm (CR) in newly-diagnosed hypertensives (NDH) as a function of the chronological age in which hypertension became manifest.

MATERIALS AND METHODS

The study was performed on 141 NDH (71 males and 70 females, ranging in age from 24 year to 79 years), who were monitored in their 24-h BP via a non-invasive, ambulatory, automated recorder. The relation between the properties of BP CR and the age of the development of hypertension was investigated via the Clinospectror method, a trend analysis (periodic-linear regression method) for rhythmic biophenomena.

RESULTS

A trend was detected for each one of the three properties of BP CR in relation with the age in which high BP made its appearance. As a matter of fact, the daily mean level (mesor) of BP CR was seen to be progressively less pronounced. The amplitude was found to show a progressive increment of its extent. The acrophase was seen to show a progressive antemeridian rotation of its timing.

CONCLUSIONS

These trends suggest that hypertension tends to be less severe when its development occurs in subjects older in age. Such a less pronounced severity is, however, accompanied by a more pronounced oscillation of BP values during the 24-h of the day. Such a higher circadian variability, in turn, tends to show its highest expression during the morning hours of the day.

Small bowel necrosis associated with postoperative enteral feeding

Enteral feeding by jejunostomy is one of the main surgical procedures used to supply the proteins and calories necessary in the early postoperative period after major surgery of the upper digestive tract. The complications associated with early postoperative enteral feeding may vary from signs of gastrointestinal intolerance such as nausea, emesis, diarrhoea and cramp-like abdominal pain to hypotension and hypovolaemic shock, and also to the development of small bowel ischaemia and necrosis. Ischaemic intestinal involvement with progression towards necrosis is fortunately a rare event. The cause is not well known. A multifactorial pathogenesis of the mucosal damage has been proposed, where hyperosmolarity of feeding and bacterial overgrowth, due to excessive fermentation of carbohydrates, a decreased mesenteric blood flow and a lowering of peristalsis have been adduced as causes of mucosal injury. We report a case of intestinal necrosis following a jejunostomy procedure, which led to ileal resection.

Circadian rhythm of hunger sensation in patients affected by dysthymic disorder

PURPOSE

The present study investigates the daily pattern of hunger sensation (HS), namely orexia, in patients affected by "Dysthymic Disorder" (DD). The aim is to detect whether there are changes in the circadian rhythm (CR) of HS, herein investigated as a "marker rhythm", that can reveal a dysfunction of the "circadian biological clock" (CBC). In such a circumstance, one could be authorised to suggest a resynchronizing therapy, via antidepressant chronizing drugs and/or morning exposure to bright light, as it is currently done in other types of human depression, having a documented dysfunction of the CBC.

MATERIALS AND METHODS

Volunteered with informed consent for the study 6 women (age = 34-56 years; mean BMI = 22.7 +/- 4.8 kg/m2) affected by DD. 10 clinically healthy women (CHW, age = 21-52 years; mean BMI = 24.0 +/- 0.5 kg/m2) were recruited as the controls. Both of the dysthymic patients (DP) and CHW were asked to compile the "orexigram", which was chronobiometrically analyzed by means of the 1. conventional statistical methods; 2. rhythmometric analysis for the CR; 3. spectral analysis for the harmonic components of the orexigram.

RESULTS

The DP were found to be characterized by a normal daily level of HS, with 1. the CR of the orectic stimulus to be preserved and well located in its acrophase, and 2. the spectrogram of the orexigram to be substantially well configured.

CONCLUSIONS

The above-cited results suggest that the DP show no alterations in the HS marker rhythm that can be taken as an evidence for declaring that the DD is not characterized by a relevant dysfunction of the CBC. Lacking in particular a phase-shift in HS marker rhythm, it can be argued that the DD is an affective disorder for which a resynchronizing therapy (exposure to bright light or pharmacological chronizers) seems to be "a priori" not indicated.

Circadian rhythm of hunger sensation in obese patients: effects of a short-term, moderately hypocaloric diet with a substitutive meal

This investigation deals with the circadian rhythm (CR) of hunger sensation (HS) in obese patients before and after a four-week, moderately hypocaloric diet with a substitutive meal. The study was performed on 25 non-diabetic obese patients (5 males and 20 females, mean age: 39.7 +/- 7, mean BMI: 27.9 1.4 Kg/m2), whose obesity was not associated with impaired glucose tolerance (IGT), binge eating, nor endocrine diseases. Their daily HS profile (orexigram) was analysed chronobiometrically. The moderately hypocaloric diet with a substitutive meal reduced the daily HS by about 10% by the fourth week. This reduction was apparently due to a tonic and amplitude modulation of the HS CR and was not accompanied by its disruption. No conclusions, however, could be drawn with regard to its orectic and clinical effects beyond four weeks.

Zymographic analysis of circulating and tissue forms of colon carcinoma gelatinase A (MMP-2) and B (MMP-9) separated by mono- and two-dimensional electrophoresis

Gelatinase A (MMP-2) and gelatinase B (MMP-9) play a key role in the proteolytic cascade leading to ECM degradation during invasion and metastasis. The enzyme activity is regulated both at the intra- and extra-cellular level. Extracellular regulation is achieved mainly through the balance between proenzyme activation and inhibition, which appears to be altered in cancer patients. One of the mechanisms of MMP inhibition is the binding of the enzymes to appropriate tissue inhibitors (TIMP). In the recent literature, it has been suggested that MMP-2 and/or MMP-9 are indeed over-produced in many carcinomas, while the identity of the various enzymatic forms (latent, activated and enzyme/inhibitor complexes) remains to be elucidated. In this study we have analyzed the circulating forms of MMP-9 and MMP-2 in serum samples of patients with colon carcinoma, as well as the enzymatic activities present in tissue extracts from surgical fragments (primary tumor and its paired healthy tissue). Proteins were separated by means of mono-dimensional or bidimensional electrophoresis, and the enzymes detected by gelatin zymography and immunological assays. The results of densitometric analyses demonstrate that proMMP-9, but not proMMP-2, is significantly higher in the oncologic sera vs. the normal sera. In addition, several oligomeric circulating and tissue forms of MMP-9 are preferentially found in the oncologic samples, both in mono- and second-dimension zymograms. The activated forms of MMP-2 and MMP-9 are uniquely present in the primary tumor extracts, thus confirming the involvement of the tissue microenvironment in gelatinase activation and function.

[Daily sensation of hunger, before and after phototherapy, in subjects with depression-type seasonal affective disorder]

OBJECTIVE

The present study investigates the daily pattern of hunger sensation (HS) in women affected by "seasonal affective disorder--depression type" (SAD-DT), before and after therapeutic exposure to bright light (phototherapy). The aim is to detect whether there are disorders in daily HS during the active phase of the disease which can be normalized by an effective treatment of the depressive status, via phototherapy.

MATERIALS AND METHODS

Volunteered for the study 4 women affected by SAD-DT, 32-58 years old (BMI: 17.8-29.6 Kg/m2); 10 clinically healthy women (CHW), 21-52 years old (BMI: 23 e 25 Kg/m2) were recruited as controls. Both of the SAD-DT patients and CHW were asked to compile the "orexigram", which was chronobiometrically analyzed by means of the 1. conventional statistical methods; 2. rhythmometric analysis; 3. spectral analysis.

RESULTS

Before phototherapy, the SAD-DT patients were found to be characterized by an increased HS (hyperorexia), with the circadian rhythm of the orectic stimulus (OS) which is shifted in its acrophase, being prone to become "free running". After phototherapy, the SAD-DT patients were found to show a little insignificant decrease in their OS, which still maintains a delayed phase in its circadian rhythm as well as the tendency to be "free running".

CONCLUSIONS

The pre-treatment findings suggest that the SAD-DT patients are affected by hyperorexia associated with a "phase-shift" for the circadian periodicity of their HS, which is prone to the desynchronization. Such a dyschronism reinforces the hypothesis that the SAD-DT may be pathogenetically sustained by a mechanism of "phase-shift". The post-treatment findings suggest that both the hyperorexia and dyschronism of the orectic circadian rhythm are uncorrected by the phototherapy, even though the SAD-DT patients seem to have had beneficial antidepressive effects from the therapeutic intervention. The persisting dyschronism indicates that the photic stimulus is not able to completely reset the biological clock of the suprachiasmatic nuclei, at least for the phasic modulation of the HS circadian rhythm. The orexigram, thus, could be enclosed among the clinical tools in order to assess the complete efficacy of the phototherapy in SAD-DP patients.

Development and validation of a high-performance liquid chromatography-tandem mass spectrometry assay for the determination of sanfetrinem in human plasma

A rapid, selective and accurate high-performance liquid chromatography-tandem mass spectrometry assay for the quantification of sanfetrinem in human plasma has been developed and validated. The performance of manual and automated sample preparation was assessed; 50 microl of plasma sample was deproteinized with acetonitrile, followed by dilution with water and injection onto the LC system. Chromatographic separation was achieved on a Phenomenex Luna C18(2), 50x2.0 (5 microm) column with a mobile phase consisting of water-acetonitrile with 0.1% formic acid followed by detection with a Perkin-Elmer API3000 mass spectrometer in multiple reaction monitoring mode. The lower limit of quantification was improved by five times compared to the UV method previously reported. A range of concentration from 10 ng/ml to 5 microg/ml was covered. The method was applied to the quantification of sanfetrinem in human plasma samples from healthy volunteers participating in a clinical study.