Novel insights into the mechanisms mediating the local antihypertrophic effects of cardiac atrial natriuretic peptide: role of cGMP-dependent protein kinase and RGS2

Cardiac atrial natriuretic peptide (ANP) locally counteracts cardiac hypertrophy via the guanylyl cyclase-A (GC-A) receptor and cGMP production, but the downstream signalling pathways are unknown. Here, we examined the influence of ANP on β-adrenergic versus Angiotensin II (Ang II)-dependent (Gs vs. Gαq mediated) modulation of Ca2+i-handling in cardiomyocytes and of hypertrophy in intact hearts. L-type Ca2+ currents and Ca2+i transients in adult isolated murine ventricular myocytes were studied by voltage-clamp recordings and fluorescence microscopy. ANP suppressed Ang II-stimulated Ca2+ currents and transients, but had no effect on isoproterenol stimulation. Ang II suppression by ANP was abolished in cardiomyocytes of mice deficient in GC-A, in cyclic GMP-dependent protein kinase I (PKG I) or in the regulator of G protein signalling (RGS) 2, a target of PKG I. Cardiac hypertrophy in response to exogenous Ang II was significantly exacerbated in mice with conditional, cardiomyocyte-restricted GC-A deletion (CM GC-A KO). This was concomitant to increased activation of the Ca2+/calmodulin-dependent prohypertrophic signal transducer CaMKII. In contrast, β-adrenoreceptor-induced hypertrophy was not enhanced in CM GC-A KO mice. Lastly, while the stimulatory effects of Ang II on Ca2+-handling were absent in myocytes of mice deficient in TRPC3/TRPC6, the effects of isoproterenol were unchanged. Our data demonstrate a direct myocardial role for ANP/GC-A/cGMP to antagonize the Ca2+i-dependent hypertrophic growth response to Ang II, but not to β-adrenergic stimulation. The selectivity of this interaction is determined by PKG I and RGS2-dependent modulation of Ang II/AT1 signalling. Furthermore, they strengthen published observations in neonatal cardiomyocytes showing that TRPC3/TRPC6 channels are essential for Ang II, but not for β-adrenergic Ca2+i-stimulation in adult myocytes

Hepatocyte Growth Factor (HGF) Inhibits Collagen I and IV Synthesis in Hepatic Stellate Cells by miRNA-29 Induction

BACKGROUND: In chronic liver disease, hepatic stellate cells (HSC) transdifferentiate into myofibroblasts, promoting extracellular matrix (ECM) synthesis and deposition. Stimulation of HSC by transforming growth factor-β (TGF-β) is a crucial event in liver fibrogenesis due to its impact on myofibroblastic transition and ECM induction. In contrast, hepatocyte growth factor (HGF), exerts antifibrotic activities. Recently, miR-29 has been reported to be involved in ECM synthesis. We therefore studied the influence of HGF and TGF-β on the miR-29 collagen axis in HSC. METHODOLOGY: HSC, isolated from rats, were characterized for HGF and Met receptor expression by Real-Time PCR and Western blotting during culture induced myofibroblastic transition. Then, the levels of TGF-β, HGF, collagen-I and -IV mRNA, in addition to miR-29a and miR-29b were determined after HGF and TGF-β stimulation of HSC or after experimental fibrosis induced by bile-duct obstruction in rats. The interaction of miR-29 with 3'-untranslated mRNA regions (UTR) was analyzed by reporter assays. The repressive effect of miR-29 on collagen synthesis was studied in HSC treated with miR-29-mimicks by Real-Time PCR and immunoblotting. PRINCIPAL FINDINGS: The 3'-UTR of the collagen-1 and -4 subtypes were identified to bind miR-29. Hence, miR-29a/b overexpression in HSC resulted in a marked reduction of collagen-I and -IV synthesis. Conversely, a decrease in miR-29 levels is observed during collagen accumulation upon experimental fibrosis, in vivo, and after TGF-β stimulation of HSC, in vitro. Finally, we show that during myofibroblastic transition and TGF-β exposure the HGF-receptor, Met, is upregulated in HSC. Thus, whereas TGF-β stimulation leads to a reduction in miR-29 expression and de-repression of collagen synthesis, stimulation with HGF was definitely associated with highly elevated miR-29 levels and markedly repressed collagen-I and -IV synthesis. CONCLUSIONS: Upregulation of miRNA-29 by HGF and downregulation by TGF-β take part in the anti- or profibrogenic response of HSC, respectively

First Latin American clinical practice guidelines for the treatment of systemic lupus erythematosus: Latin American Group for the Study of Lupus (GLADEL, Grupo Latino Americano de Estudio del Lupus)-Pan-American League of Associations of Rheumatology (PANLAR)

Systemic lupus erythematosus (SLE), a complex and heterogeneous autoimmune disease, represents a significant challenge for both diagnosis and treatment. Patients with SLE in Latin America face special problems that should be considered when therapeutic guidelines are developed. The objective of the study is to develop clinical practice guidelines for Latin American patients with lupus. Two independent teams (rheumatologists with experience in lupus management and methodologists) had an initial meeting in Panama City, Panama, in April 2016. They selected a list of questions for the clinical problems most commonly seen in Latin American patients with SLE. These were addressed with the best available evidence and summarised in a standardised format following the Grading of Recommendations Assessment, Development and Evaluation approach. All preliminary findings were discussed in a second face-to-face meeting in Washington, DC, in November 2016. As a result, nine organ/system sections are presented with the main findings; an 'overarching' treatment approach was added. Special emphasis was made on regional implementation issues. Best pharmacologic options were examined for musculoskeletal, mucocutaneous, kidney, cardiac, pulmonary, neuropsychiatric, haematological manifestations and the antiphospholipid syndrome. The roles of main therapeutic options (ie, glucocorticoids, antimalarials, immunosuppressant agents, therapeutic plasma exchange, belimumab, rituximab, abatacept, low-dose aspirin and anticoagulants) were summarised in each section. In all cases, benefits and harms, certainty of the evidence, values and preferences, feasibility, acceptability and equity issues were considered to produce a recommendation with special focus on ethnic and socioeconomic aspects. Guidelines for Latin American patients with lupus have been developed and could be used in similar settings.Fil: Pons Estel, Bernardo A.. Centro Regional de Enfermedades Autoinmunes y Reumáticas; ArgentinaFil: Bonfa, Eloisa. Universidade de Sao Paulo; BrasilFil: Soriano, Enrique R.. Instituto Universitario Hospital Italiano de Buenos Aires. Rectorado.; ArgentinaFil: Cardiel, Mario H.. Centro de Investigación Clínica de Morelia; MéxicoFil: Izcovich, Ariel. Hospital Alemán; ArgentinaFil: Popoff, Federico. Hospital Aleman; ArgentinaFil: Criniti, Juan M.. Hospital Alemán; ArgentinaFil: Vásquez, Gloria. Universidad de Antioquia; ColombiaFil: Massardo, Loreto. Universidad San Sebastián; ChileFil: Duarte, Margarita. Hospital de Clínicas; ParaguayFil: Barile Fabris, Leonor A.. Hospital Angeles del Pedregal; MéxicoFil: García, Mercedes A.. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Amigo, Mary Carmen. Centro Médico Abc; MéxicoFil: Espada, Graciela. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Catoggio, Luis J.. Hospital Italiano. Instituto Universitario. Escuela de Medicina; ArgentinaFil: Sato, Emilia Inoue. Universidade Federal de Sao Paulo; BrasilFil: Levy, Roger A.. Universidade do Estado de Rio do Janeiro; BrasilFil: Acevedo Vásquez, Eduardo M.. Universidad Nacional Mayor de San Marcos; PerúFil: Chacón Díaz, Rosa. Policlínica Méndez Gimón; VenezuelaFil: Galarza Maldonado, Claudio M.. Corporación Médica Monte Sinaí; EcuadorFil: Iglesias Gamarra, Antonio J.. Universidad Nacional de Colombia; ColombiaFil: Molina, José Fernando. Centro Integral de Reumatología; ColombiaFil: Neira, Oscar. Universidad de Chile; ChileFil: Silva, Clóvis A.. Universidade de Sao Paulo; BrasilFil: Vargas Peña, Andrea. Hospital Pasteur Montevideo; UruguayFil: Gómez Puerta, José A.. Hospital Clinic Barcelona; EspañaFil: Scolnik, Marina. Instituto Universitario Hospital Italiano de Buenos Aires. Rectorado.; ArgentinaFil: Pons Estel, Guillermo J.. Centro Regional de Enfermedades Autoinmunes y Reumáticas; Argentina. Hospital Provincial de Rosario; ArgentinaFil: Ugolini Lopes, Michelle R.. Universidade de Sao Paulo; BrasilFil: Savio, Verónica. Instituto Universitario Hospital Italiano de Buenos Aires. Rectorado.; ArgentinaFil: Drenkard, Cristina. University of Emory; Estados UnidosFil: Alvarellos, Alejandro J.. Hospital Privado Universitario de Córdoba; ArgentinaFil: Ugarte Gil, Manuel F.. Universidad Cientifica del Sur; Perú. Hospital Nacional Guillermo Almenara Irigoyen; PerúFil: Babini, Alejandra. Instituto Universitario Hospital Italiano de Buenos Aires. Rectorado.; ArgentinaFil: Cavalcanti, André. Universidade Federal de Pernambuco; BrasilFil: Cardoso Linhares, Fernanda Athayde. Hospital Pasteur Montevideo; UruguayFil: Haye Salinas, Maria Jezabel. Hospital Privado Universitario de Córdoba; ArgentinaFil: Fuentes Silva, Yurilis J.. Universidad de Oriente - Núcleo Bolívar; VenezuelaFil: Montandon De Oliveira E Silva, Ana Carolina. Universidade Federal de Goiás; BrasilFil: Eraso Garnica, Ruth M.. Universidad de Antioquia; ColombiaFil: Herrera Uribe, Sebastián. Hospital General de Medellin Luz Castro de Gutiérrez; ColombiaFil: Gómez Martín, DIana. Instituto Nacional de la Nutrición Salvador Zubiran; MéxicoFil: Robaina Sevrini, Ricardo. Universidad de la República; UruguayFil: Quintana, Rosana M.. Hospital Provincial de Rosario; Argentina. Centro Regional de Enfermedades Autoinmunes y Reumáticas; ArgentinaFil: Gordon, Sergio. Hospital Interzonal General de Agudos Dr Oscar Alende. Unidad de Reumatología y Enfermedades Autoinmunes Sistémicas; ArgentinaFil: Fragoso Loyo, Hilda. Instituto Nacional de la Nutrición Salvador Zubiran; MéxicoFil: Rosario, Violeta. Hospital Docente Padre Billini; República DominicanaFil: Saurit, Verónica. Hospital Privado Universitario de Córdoba; ArgentinaFil: Appenzeller, Simone. Universidade Estadual de Campinas; BrasilFil: Dos Reis Neto, Edgard Torres. Universidade Federal de Sao Paulo; BrasilFil: Cieza, Jorge. Hospital Nacional Edgardo Rebagliati Martins; PerúFil: González Naranjo, Luis A.. Universidad de Antioquia; ColombiaFil: González Bello, Yelitza C.. Ceibac; MéxicoFil: Collado, María Victoria. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Sarano, Judith. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Retamozo, Maria Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Ciencias de la Salud. Universidad Nacional de Córdoba. Instituto de Investigaciones en Ciencias de la Salud; ArgentinaFil: Sattler, María E.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Gamboa Cárdenas, Rocio V.. Hospital Nacional Guillermo Almenara Irigoyen; PerúFil: Cairoli, Ernesto. Universidad de la República; UruguayFil: Conti, Silvana M.. Hospital Provincial de Rosario; ArgentinaFil: Amezcua Guerra, Luis M.. Instituto Nacional de Cardiologia Ignacio Chavez; MéxicoFil: Silveira, Luis H.. Instituto Nacional de Cardiologia Ignacio Chavez; MéxicoFil: Borba, Eduardo F.. Universidade de Sao Paulo; BrasilFil: Pera, Mariana A.. Hospital Interzonal General de Agudos General San Martín; ArgentinaFil: Alba Moreyra, Paula B.. Universidad Nacional de Córdoba. Facultad de Medicina; ArgentinaFil: Arturi, Valeria. Hospital Interzonal General de Agudos General San Martín; ArgentinaFil: Berbotto, Guillermo A.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Gerling, Cristian. Hospital Interzonal General de Agudos Dr Oscar Alende. Unidad de Reumatología y Enfermedades Autoinmunes Sistémicas; ArgentinaFil: Gobbi, Carla Andrea. Universidad Nacional de Córdoba. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gervasoni, Viviana L.. Hospital Provincial de Rosario; ArgentinaFil: Scherbarth, Hugo R.. Hospital Interzonal General de Agudos Dr Oscar Alende. Unidad de Reumatología y Enfermedades Autoinmunes Sistémicas; ArgentinaFil: Brenol, João C. Tavares. Hospital de Clinicas de Porto Alegre; BrasilFil: Cavalcanti, Fernando. Universidade Federal de Pernambuco; BrasilFil: Costallat, Lilian T. Lavras. Universidade Estadual de Campinas; BrasilFil: Da Silva, Nilzio A.. Universidade Federal de Goiás; BrasilFil: Monticielo, Odirlei A.. Hospital de Clinicas de Porto Alegre; BrasilFil: Seguro, Luciana Parente Costa. Universidade de Sao Paulo; BrasilFil: Xavier, Ricardo M.. Hospital de Clinicas de Porto Alegre; BrasilFil: Llanos, Carolina. Universidad Católica de Chile; ChileFil: Montúfar Guardado, Rubén A.. Instituto Salvadoreño de la Seguridad Social; El SalvadorFil: Garcia De La Torre, Ignacio. Hospital General de Occidente; MéxicoFil: Pineda, Carlos. Instituto Nacional de Rehabilitación; MéxicoFil: Portela Hernández, Margarita. Umae Hospital de Especialidades Centro Medico Nacional Siglo Xxi; MéxicoFil: Danza, Alvaro. Hospital Pasteur Montevideo; UruguayFil: Guibert Toledano, Marlene. Medical-surgical Research Center; CubaFil: Reyes, Gil Llerena. Medical-surgical Research Center; CubaFil: Acosta Colman, Maria Isabel. Hospital de Clínicas; ParaguayFil: Aquino, Alicia M.. Hospital de Clínicas; ParaguayFil: Mora Trujillo, Claudia S.. Hospital Nacional Edgardo Rebagliati Martins; PerúFil: Muñoz Louis, Roberto. Hospital Docente Padre Billini; República DominicanaFil: García Valladares, Ignacio. Centro de Estudios de Investigación Básica y Clínica; MéxicoFil: Orozco, María Celeste. Instituto de Rehabilitación Psicofísica; ArgentinaFil: Burgos, Paula I.. Pontificia Universidad Católica de Chile; ChileFil: Betancur, Graciela V.. Instituto de Rehabilitación Psicofísica; ArgentinaFil: Alarcón, Graciela S.. Universidad Peruana Cayetano Heredia; Perú. University of Alabama at Birmingahm; Estados Unido

Abstracts from the 8th International Conference on cGMP Generators, Effectors and Therapeutic Implications

This work was supported by a restricted research grant of Bayer AG

Die Rolle der cGMP-abhängigen Proteinkinase Typ I bei der Regulation der Stressantwort und Thermogenese

The cGMP-dependent protein kinase type I (cGKI) mediates many physiological functions of NO/cGMP signalling, which has been suggested to modulate the stress response and to be involved in thermogenesis, but it is still unclear, whether cGKI represents the major cGMP effector in these processes. In this study, cGKI expression was demonstrated in tissues of the hypothalamic-pituitary-adrenal (HPA) axis, the main mediator of the stress response, and a potential function of cGKI in HPA axis regulation was investigated in vivo in mice by injection of interleukin-1 beta (IL-1 beta). Neuron-specific cGKI knock-out (KO) mice responded like control mice. However, cGKI smooth muscle specific rescue mice (SM-I beta rescues), in which expression of the cGKI beta isoform has been restored selectively in smooth muscle cells of cGKI KO mice, showed significantly higher adrenocorticotropic hormone (ACTH), but lower corticosterone (CORT) levels than control littermates after stimulation indicating a reduced sensitivity of their adrenal glands to ACTH. The observed effect was not limited to immunological challenges, because also restraint stress led to a diminished rise in CORT levels in SM-I beta rescue mice. Surprisingly, cGKI expression was not detectable in parenchymal steroidogenic cells, but the demonstration of cGKI in fibroblast-like cells located between the CORT-producing cells of the zona fasciculata suggested a paracrine effect of cGKI-positive cells on CORT production and/or secretion. However, ACTH stimulation of adrenal slices and in vivo stimulation of SM I beta rescue mice with ACTH caused controversial results. Thus, it still needs to be deciphered, whether the in vivo sensitivity to ACTH is disturbed in SM-I beta rescue mice or whether a signal other than ACTH is involved in cGKIs’ influence on plasma CORT levels. To analyse the role of cGKI in thermogenesis, core body temperature was measured telemetrically at room temperature (RT) and during cold and fasting stress. At RT, SM-I beta rescue mice showed a significantly reduced core body temperature during the light phase as compared to controls. Since neuron-specific cGKI KO mice had core body temperatures indistinguishable from controls, the function of cGKI in thermoregulation at RT is probably not localised in the brain. However, following cold and fasting stress, core body temperature of neuron-specific cGKI KO mice dropped more rapidly than the core body temperature of control mice. Since cGKI expression in these mice is missing in brain nuclei that are involved in thermoregulation, in peripheral nerves innervating BAT and in distinct cells in BAT that still need to be characterised, more studies are required to define the exact mechanism, how cGKI influences thermogenesis. In summary, this study demonstrates a role for cGKI in the modulation of the HPA axis as well as in thermogenesis in mice, but the underlying cellular and molecular mechanisms need to be further deciphered. In the future, cGKI might provide an interesting target for the treatment of diseases caused by HPA axis dysregulation such as depression or for BAT-dependent treatment of adipositas.Die cGMP-abhängige Proteinkinase Typ I (cGKI) vermittelt zahlreiche physiologische Effekte der NO/cGMP-Signalkaskade, welcher auch eine Beteiligung an der Modulation der Stressantwort und bei der Thermogenese zugeschrieben wird. Bislang ist jedoch nicht bekannt, ob diese Effekte durch die cGKI vermittelt werden. Im Rahmen dieser Arbeit wurde nachgewiesen, dass die cGKI in den Geweben der Hypothalamus-Hypophysen-Nebennieren-Achse (HPA-Achse), die maßgeblich an der Stressantwort beteiligt ist, exprimiert wird. Eine mögliche physiologische Funktion der cGKI bei der Regulation der HPA-Achse wurde in vivo in Mäusen untersucht, deren HPA-Achse durch Injektion von Interleukin-1 beta (IL-1 beta) stimuliert wurde. Neuronen-spezifische cGKI knock-out (KO) Mäuse reagierten ähnlich wie Kontrollmäuse. In cGKI Glattmuskel-spezifischen Rescue-Mäusen (SM-I beta Rescue-Mäusen), in denen die Expression der cGKI beta-Isoform selektiv im glatten Muskel von cGKI KO Mäusen wiederhergestellt ist, waren jedoch im Vergleich zu Kontrolltieren die ACTH-Plasmawerte nach Stimulation mit IL-1 beta signifikant erhöht und die Kortikosteron-Plasmawerte erniedrigt. Dies weist auf eine erniedrigte Sensitivität der Nebennieren gegenüber ACTH in SM-I beta Rescue-Mäusen hin. Eine veränderte Stressantwort in SM-I beta Rescue-Mäusen war nicht nur nach der IL-1 beta Injektion, einem immunologischen Stresstyp, zu beobachten. Auch Immobilisierungsstress, der eine Mischung aus physischem und psychologischem Stress darstellt, führte verglichen mit Kontrolltieren in SM-I beta Rescue-Mäusen zu einer geringeren Erhöhung der Kortikosteronkonzentration im Plasma. Interessanterweise war in den parenchymalen Kortikosteron-produzierenden Zellen keine cGKI-Expression nachweisbar. Dafür konnte cGKI in Fibroblasten-ähnlichen Zellen, die zwischen den Kortikosteron-produzierenden Zellen der Zona Fasciculata lokalisiert waren, nachgewiesen werden. Daher ist ein parakriner Einfluss der cGKI-positiven Zellen auf die Kortikosteron-Produktion und/oder Sekretion naheliegend. Allerdings führte die Stimulation mit ACTH in Nebennieren-Gewebsschnitten und in vivo in SM-I beta Rescue-Mäusen zu widersprüchlichen Ergebnissen. Daher ist noch unklar, ob die ACTH-Sensitivität in SM-I beta Rescue-Mäusen in vivo verändert ist oder ob der Einfluss der cGKI auf die Kortikosteronkonzentration im Plasma ACTH-unabhängig ist. Um die Funktion der cGKI bei der Thermogenese zu untersuchen, wurde die Körperkerntemperatur bei Raumtemperatur und während Kälte-und Fastenstresses telemetrisch erfasst. Bei Raumtemperatur zeigten SM-I beta Rescue-Mäuse während der Lichtphase eine gegenüber den Kontrolltieren signifikant erniedrigte Körperkerntemperatur. Da sich die Körperkerntemperatur in den Neuronen-spezifischen cGKI-KO Mäusen nicht von den Kontrolltieren unterschied, kann davon ausgegangen werden, dass die Funktion der cGKI für die Thermoregulation bei Raumtemperatur nicht im Nervensystem lokalisiert ist. Jedoch fiel die Körperkerntemperatur in den Neuronen-spezifischen cGKI KO-Mäusen während des Kälte- und Fastenstresses sehr viel schneller ab als in Kontrolltieren. Diese Daten zeigen, dass cGKI-abhängige Signalwege die Thermogenese in vivo stimulieren. Ob diese Funktion der cGKI auf ihre Expression in Kerngebieten des Gehirns, die an der Thermoregulation beteiligt sind, zurückzuführen ist oder ob eine Funtkon der cGKI im braunen Fettgewebe, in dem die cGKI in Neuronen-spezifischen cGKI-KO Mäusen auch reduziert ist, darstellt, ist bislang noch unklar. Zusammengefasst zeigt diese Studie eine Rolle der cGKI bei der Regulation der HPA-Achse und bei der Thermogenese in Mäusen, wobei die zugrundeliegenden zellulären und molekularen Mechanismen noch weiter aufgeklärt werden müssen. In der Zukunft könnte die cGKI ein interessantes Zielprotein für die Behandlung von Krankheiten bieten, die durch einen Fehlregulation der HPA-Achse verursacht werden, wie beispielsweise Depressionen, sowie für Therapieformen zur Behandlung der Adipositas, die auf der Stimulation der Thermogenese in braunem Fettgewebe basieren

Ciprofloxacin, Enrofloxacin, Lincomycin, Penicillin G und Penicillin V – Bestimmung von ausgewählten Antibiotika in Urin mittels LC‐MS/MS. Biomonitoring-Methode

The working group “Analyses in Biological Materials” of the Permanent Senate Com- mission for the Investigation of Health Hazards of Chemical Compounds in the Work Area developed and verified the presented biomonitoring method. This method allows for the sensitive and precise determination of selected antibiotics (ciprofloxacin, enrofloxacin, lincomycin, penicillin G, and penicillin V) in human urine. Sample preparation includes extracting the analytes by solid-phase extraction on Oasis HLB cartridges, followed by concentrating the eluates under a stream of nitrogen. The analytes are separated from matrix compounds by liquid chromatography and sub- sequently detected with tandem mass spectrometry using electrospray ionisation. Quantitative evaluation is carried out via external calibration in urine. The good precision data and accuracy data show that the method provides reliable and accurate measurement values. Any matrix effects are effectively compensated for by the use of isotope-labelled internal standards. This finding holds similarly true for cipro- floxacin, for which isotope-labelled enrofloxacin was used as internal standard (ISTD). With quantitation limits of 0.1 μg/l for ciprofloxacin, enrofloxacin, and lincomycin as well as 0.3 μg/l for penicillin G and penicillin V, this method is very sensitive and enables the reliable quantitation of occupational exposure to the selected antibiotics