The Noble Suicide: The Case of a Self-Contained Dagger in the Heart and a Literal Raw.

According to WHO estimates, more than 700,000 people die each year due to suicide and suicides performed with a bladed weapon account for approximately 1.6%-3% of all suicides. It is statistically more common to find injuries to the heart, lungs, and thoracic vessels in homicides, whereas in suicides there is a higher frequency of vascular injuries to the extremities of the limbs. Also in suicides, the presence of "hesitation marks," related to the attempts the victim makes before having the courage to kill himself, can often be found. In the case presented by the authors, these parameters are subverted: There was only one injury and it was the fatal one, it was located on the chest and reached the heart. But it was suicide. The circumstantial data, the psychological explanation, and the previous similar suicide attempt left no doubt about it. The man decided to commit suicide because he could no longer find meaning in his life after losing hope for a career as a pianist, having been diagnosed with a degenerative disease in his hands. The man hated himself and his existence: The future appeared extremely negative and the only escape was self-suppression. This case report makes an essential contribution to the already existing Literature as it shows a suicide that occurred in an unusual manner.

Fluoropyrimidines affect de novo pyrimidine synthesis impairing biofilm formation in Escherichia coli.

Antivirulence agents are considered a promising strategy to treat bacterial infections. Fluoropyrimidines possess antivirulence and antibiofilm activity against Gram-negative bacteria; however, their mechanism of action is yet unknown. Consistent with their known antibiofilm activity, fluoropyrimidines, particularly 5-fluorocytosine (5-FC), impair curli-dependent surface adhesion by Escherichia coli MG1655 via downregulation of curli fimbriae gene transcription. Curli inhibition requires fluoropyrimidine conversion into fluoronucleotides and is not mediated by c-di-GMP or the ymg-rcs envelope stress response axis, previously suggested as the target of fluorouracil antibiofilm activity in E. coli. In contrast, 5-FC hampered the transcription of curli activators RpoS and stimulated the expression of Fis, a curli repressor affected by nucleotide availability. This last observation suggested a possible perturbation of the de novo pyrimidine biosynthesis by 5-FC: indeed, exposure to 5-FC resulted in a ca. 2-fold reduction of UMP intracellular levels while not affecting ATP. Consistently, expression of the de novo pyrimidine biosynthesis genes carB and pyrB was upregulated in the presence of 5-FC. Our results suggest that the antibiofilm activity of fluoropyrimidines is mediated, at least in part, by perturbation of the pyrimidine nucleotide pool. We screened a genome library in search of additional determinants able to counteract the effects of 5-FC. We found that a DNA fragment encoding the unknown protein D8B36_18,480 and the N-terminal domain of the penicillin-binding protein 1b (PBP1b), involved in peptidoglycan synthesis, could restore curli production in the presence of 5-FC. Deletion of the PBP1b-encoding gene mrcB, induced csgBAC transcription, while overexpression of the gene encoding the D8B36_18,480 protein obliterated its expression, possibly as part of a coordinated response in curli regulation with PBP1b. While the two proteins do not appear to be direct targets of 5-FC, their involvement in curli regulation suggests a connection between peptidoglycan biosynthesis and curli production, which might become even more relevant upon pyrimidine starvation and reduced availability of UDP-sugars needed in cell wall biosynthesis. Overall, our findings link the antibiofilm activity of fluoropyrimidines to the redirection of at least two global regulators (RpoS, Fis) by induction of pyrimidine starvation. This highlights the importance of the de novo pyrimidines biosynthesis pathway in controlling virulence mechanisms in different bacteria and makes the pathway a potential target for antivirulence strategies.

Requests for Compensation in Cases Involving Patients' Falls in Healthcare Settings: A Retrospective Analysis.

Falls are the most frequent adverse events recorded in healthcare facilities. By employing a multifaceted strategy to ensure prevention interventions that are specific to the patient type and environmental risk management, risk factor evaluation may help to reduce falls in the hospital setting. Patient falls are one of the main causes of lawsuits against hospitals, which has led to the development of validated instruments that are beneficial in treating the patient after the incident and effective in minimizing the frequency of falls. The aim of our study is to evaluate compensation claims asserting healthcare culpability in situations where a patient fell in a hospital setting. The collected data relate to judgments issued in Italy until December 2022 regarding 30 episodes of falls that occurred between 2003 and 2018. Our research revealed that approximately 50% of Italian healthcare organizations lose the case in court when a patient falls in a hospital setting and dies or is injured. In half of these cases, the failure of the medical staff to use protective equipment against falls is what led to the court's acceptance of the compensation claim. In order to improve the quality of healthcare services, fall prevention techniques must continue to be implemented.

Heat Stroke in the Work Environment: Case Report of an Underestimated Phenomenon.

Average global temperatures continue to trend upward, and this phenomenon is part of the more complex climate change taking place on our planet over the past century. Human health is directly affected by environmental conditions, not only because of communicable diseases that are clearly affected by climate, but also because of the relationship between rising temperatures and increased morbidity for psychiatric diseases. As global temperatures and the number of extreme days increase, so does the risk associated with all those acute illnesses related to these factors. For example, there is a correlation between out-of-hospital cardiac arrest and heat. Then, there are pathologies that recognize excessive heat as the main etiological agent. This is the case with so-called "heat stroke", a form of hyperthermia accompanied by a systemic inflammatory response, which causes multi-organ dysfunction and sometimes death. Starting with a case that came to their attention of a young man in good general health who died while working unloading fruit crates from a truck, the authors wanted to express some thoughts on the need to adapt the world of work, including work-specific hazards, in order to protect the worker exposed to this "new risk" and develop multidisciplinary adaptation strategies that incorporate climatology, indoor/building environments, energy use, regulatory perfection of work and human thermal comfort.

Diagnostic Methods in Forensic Pathology: A New Sign in Death from Hanging.

PURPOSE: To evaluate the usefulness of studying vital injuries at the sternal head insertion of the sternocleidomastoid muscle in the medico-legal assessment of death by hanging. MATERIALS AND METHODS: Study material was obtained from eight bodies of people who died from hanging. The control group included as many specimens collected from people who died from traumatic causes other than hanging (precipitation from medium to large heights and traffic accidents). The structures under study were examined histologically with a BX-51 light microscope (Olympus). An analysis of the extravasated erythrocytes was performed by counting the number per mm2 in the histologic section on 10 HPF (400×), and Student's t-test for a comparison of the averages was applied for all parametric values. The authors noted that the key finding, indicative of the subject's viability at the time of discontinuation, was the presence of recent hemorrhagic infiltrate (in the absence of hemosiderin) at the tendon insertion of the sternocleidomastoid muscle and the proximal part of the muscle itself. RESULTS: All specimens tested were positive for the presence of hemorrhagic infiltrate at the portions tested in a statistically significant manner. In contrast, in the control cases there was no or, where present, no statistically significant (p < 0.05) presence of recent hemorrhagic infiltrate. The limitation of the study is the low number of samples examined. In any case, the results obtained are strongly indicative of the possibility of using this type of forensic pathological investigation in cases where there is a doubt in terms of a differential diagnosis between hanging (suicidal type) and suspension of a corpse in a simulation of hanging.

Healthcare Liability and Thyroidectomy: When Is the Surgeon Wrong?

Thyroid surgeries can often lead to operative complications, sometimes with consequences on the patient's health. This often leads to claims for compensation but the assessments of consultants and judges are not always objective. Based on these considerations, the authors analyzed forty-seven sentences issued between 2013 and 2022 regarding claims of alleged medical malpractice. This analysis aims to examine the cases presented in the sentences and the evaluations proposed by the judges to offer ideas for objective evaluation by the legislation in force in Italy.

The Job that Kills the Worker: Analysis of Two Case Reports on Work-Related Stress Deaths in the COVID-19 Era.

The COVID-19 pandemic caused an increasing number of corporate layoffs and downsizing, as well as causing many employees to be absent due to illness, with inevitable consequences on the health of active workers both from a physical point of view, due to the need to make up for staff and organizational shortages, and from a mental point of view, due to the inevitable consequences related to the uncertainty of the social context. This context has certainly caused an increase in work-related stress, which is the pathological outcome of a process that affects workers who are subjected to excessive (emotional-relational or high or low or inadequate activity) or improper work loads. The purpose of this paper is to evaluate the main aspects of this issue, through the analysis proposed by two case reports, both of which occurred during the COVID-19 pandemic, in which occupational stress emerged as an etiological agent in the determinism of death.

The NAD+ precursor NMN activates dSarm to trigger axon degeneration in Drosophila.

Axon degeneration contributes to the disruption of neuronal circuit function in diseased and injured nervous systems. Severed axons degenerate following the activation of an evolutionarily conserved signaling pathway, which culminates in the activation of SARM1 in mammals to execute the pathological depletion of the metabolite NAD+. SARM1 NADase activity is activated by the NAD+ precursor nicotinamide mononucleotide (NMN). In mammals, keeping NMN levels low potently preserves axons after injury. However, it remains unclear whether NMN is also a key mediator of axon degeneration and dSarm activation in flies. Here, we demonstrate that lowering NMN levels in Drosophila through the expression of a newly generated prokaryotic NMN-Deamidase (NMN-D) preserves severed axons for months and keeps them circuit-integrated for weeks. NMN-D alters the NAD+ metabolic flux by lowering NMN, while NAD+ remains unchanged in vivo. Increased NMN synthesis by the expression of mouse nicotinamide phosphoribosyltransferase (mNAMPT) leads to faster axon degeneration after injury. We also show that NMN-induced activation of dSarm mediates axon degeneration in vivo. Finally, NMN-D delays neurodegeneration caused by loss of the sole NMN-consuming and NAD+-synthesizing enzyme dNmnat. Our results reveal a critical role for NMN in neurodegeneration in the fly, which extends beyond axonal injury. The potent neuroprotection by reducing NMN levels is similar to the interference with other essential mediators of axon degeneration in Drosophila.

SARM1 is a multi-functional NAD(P)ase with prominent base exchange activity, all regulated bymultiple physiologically relevant NAD metabolites.

SARM1 is an NAD(P) glycohydrolase and TLR adapter with an essential, prodegenerative role in programmed axon death (Wallerian degeneration). Like other NAD(P)ases, it catalyzes multiple reactions that need to be fully investigated. Here, we compare these multiple activities for recombinant human SARM1, human CD38, and Aplysia californica ADP ribosyl cyclase. SARM1 has the highest transglycosidation (base exchange) activity at neutral pH and with some bases this dominates NAD(P) hydrolysis and cyclization. All SARM1 activities, including base exchange at neutral pH, are activated by an increased NMN:NAD ratio, at physiological levels of both metabolites. SARM1 base exchange occurs also in DRG neurons and is thus a very likely physiological source of calcium-mobilizing agent NaADP. Finally, we identify regulation by free pyridines, NADP, and nicotinic acid riboside (NaR) on SARM1, all of therapeutic interest. Understanding which specific SARM1 function(s) is responsible for axon degeneration is essential for its targeting in disease.

Neurotoxin-mediated potent activation of the axon degeneration regulator SARM1.

Axon loss underlies symptom onset and progression in many neurodegenerative disorders. Axon degeneration in injury and disease is promoted by activation of the NAD-consuming enzyme SARM1. Here, we report a novel activator of SARM1, a metabolite of the pesticide and neurotoxin vacor. Removal of SARM1 completely rescues mouse neurons from vacor-induced neuron and axon death in vitro and in vivo. We present the crystal structure of the Drosophila SARM1 regulatory domain complexed with this activator, the vacor metabolite VMN, which as the most potent activator yet known is likely to support drug development for human SARM1 and NMNAT2 disorders. This study indicates the mechanism of neurotoxicity and pesticide action by vacor, raises important questions about other pyridines in wider use today, provides important new tools for drug discovery, and demonstrates that removing SARM1 can robustly block programmed axon death induced by toxicity as well as genetic mutation.

A nicotinamide phosphoribosyltransferase-GAPDH interaction sustains the stress-induced NMN/NAD+ salvage pathway in the nucleus.

All cells require sustained intracellular energy flux, which is driven by redox chemistry at the subcellular level. NAD+, its phosphorylated variant NAD(P)+, and its reduced forms NAD(P)/NAD(P)H are all redox cofactors with key roles in energy metabolism and are substrates for several NAD-consuming enzymes (e.g. poly(ADP-ribose) polymerases, sirtuins, and others). The nicotinamide salvage pathway, constituted by nicotinamide mononucleotide adenylyltransferase (NMNAT) and nicotinamide phosphoribosyltransferase (NAMPT), mainly replenishes NAD+ in eukaryotes. However, unlike NMNAT1, NAMPT is not known to be a nuclear protein, prompting the question of how the nuclear NAD+ pool is maintained and how it is replenished upon NAD+ consumption. In the present work, using human and murine cells; immunoprecipitation, pulldown, and surface plasmon resonance assays; and immunofluorescence, small-angle X-ray scattering, and MS-based analyses, we report that GAPDH and NAMPT form a stable complex that is essential for nuclear translocation of NAMPT. This translocation furnishes NMN to replenish NAD+ to compensate for the activation of NAD-consuming enzymes by stressful stimuli induced by exposure to H2O2 or S-nitrosoglutathione and DNA damage inducers. These results indicate that by forming a complex with GAPDH, NAMPT can translocate to the nucleus and thereby sustain the stress-induced NMN/NAD+ salvage pathway.

Mitochondrial impairment activates the Wallerian pathway through depletion of NMNAT2 leading to SARM1-dependent axon degeneration.

Wallerian degeneration of physically injured axons involves a well-defined molecular pathway linking loss of axonal survival factor NMNAT2 to activation of pro-degenerative protein SARM1. Manipulating the pathway through these proteins led to the identification of non-axotomy insults causing axon degeneration by a Wallerian-like mechanism, including several involving mitochondrial impairment. Mitochondrial dysfunction is heavily implicated in Parkinson's disease, Charcot-Marie-Tooth disease, hereditary spastic paraplegia and other axonal disorders. However, whether and how mitochondrial impairment activates Wallerian degeneration has remained unclear. Here, we show that disruption of mitochondrial membrane potential leads to axonal NMNAT2 depletion in mouse sympathetic neurons, increasing the substrate-to-product ratio (NMN/NAD) of this NAD-synthesising enzyme, a metabolic fingerprint of Wallerian degeneration. The mechanism appears to involve both impaired NMNAT2 synthesis and reduced axonal transport. Expression of WLDS and Sarm1 deletion both protect axons after mitochondrial uncoupling. Blocking the pathway also confers neuroprotection and increases the lifespan of flies with Pink1 loss-of-function mutation, which causes severe mitochondrial defects. These data indicate that mitochondrial impairment replicates all the major steps of Wallerian degeneration, placing it upstream of NMNAT2 loss, with the potential to contribute to axon pathology in mitochondrial disorders.

Homozygous NMNAT2 mutation in sisters with polyneuropathy and erythromelalgia.

We identified a homozygous missense mutation in the gene encoding NAD synthesizing enzyme NMNAT2 in two siblings with childhood onset polyneuropathy with erythromelalgia. No additional homozygotes for this rare allele, which leads to amino acid substitution T94M, were present among the unaffected relatives tested or in the 60,000 exomes of the ExAC database. For axons to survive, axonal NMNAT2 activity has to be maintained above a threshold level but the T94M mutation confers a partial loss of function both in the ability of NMNAT2 to support axon survival and in its enzymatic properties. Electrophysiological tests and histological analysis of sural nerve biopsies in the patients were consistent with loss of distal sensory and motor axons. Thus, it is likely that NMNAT2 mutation causes this pain and axon loss phenotype making this the first disorder associated with mutation of a key regulator of Wallerian-like axon degeneration in humans. This supports indications from numerous animal studies that the Wallerian degeneration pathway is important in human disease and raises important questions about which other human phenotypes could be linked to this gene.

Severe biallelic loss-of-function mutations in nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2) in two fetuses with fetal akinesia deformation sequence.

The three nicotinamide mononucleotide adenylyltransferase (NMNAT) family members synthesize the electron carrier nicotinamide adenine dinucleotide (NAD+) and are essential for cellular metabolism. In mammalian axons, NMNAT activity appears to be required for axon survival and is predominantly provided by NMNAT2. NMNAT2 has recently been shown to also function as a chaperone to aid in the refolding of misfolded proteins. Nmnat2 deficiency in mice, or in its ortholog dNmnat in Drosophila, results in axon outgrowth and survival defects. Peripheral nerve axons in NMNAT2-deficient mice fail to extend and innervate targets, and skeletal muscle is severely underdeveloped. In addition, removing NMNAT2 from established axons initiates axon death by Wallerian degeneration. We report here on two stillborn siblings with fetal akinesia deformation sequence (FADS), severely reduced skeletal muscle mass and hydrops fetalis. Clinical exome sequencing identified compound heterozygous NMNAT2 variant alleles in both cases. Both protein variants are incapable of supporting axon survival in mouse primary neuron cultures when overexpressed. In vitro assays demonstrate altered protein stability and/or defects in NAD+ synthesis and chaperone functions. Thus, both patient NMNAT2 alleles are null or severely hypo-morphic. These data indicate a previously unknown role for NMNAT2 in human neurological development and provide the first direct molecular evidence to support the involvement of Wallerian degeneration in a human axonal disorder. SIGNIFICANCE: Nicotinamide Mononucleotide Adenylyltransferase 2 (NMNAT2) both synthesizes the electron carrier Nicotinamide Adenine Dinucleotide (NAD+) and acts a protein chaperone. NMNAT2 has emerged as a major neuron survival factor. Overexpression of NMNAT2 protects neurons from Wallerian degeneration after injury and declining levels of NMNAT2 have been implicated in neurodegeneration. While the role of NMNAT2 in neurodegeneration has been extensively studied, the role of NMNAT2 in human development remains unclear. In this work, we present the first human variants in NMNAT2 identified in two fetuses with severe skeletal muscle hypoplasia and fetal akinesia. Functional studies in vitro showed that the mutations impair both NMNAT2 NAD+ synthase and chaperone functions. This work identifies the critical role of NMNAT2 in human development.

Neoadjuvant chemotherapy for stage III and IVA thymomas: a single-institution experience with a long follow-up.

BACKGROUND: Since 1989 we have enrolled patients with clinical-radiological stage III-IVA thymomas, independent of the surgeon's judgment of resectability, into a prospective study of neoadjuvant chemotherapy-surgery and postoperative radiotherapy. In this article, we review our long-term experience of neoadjuvant chemotherapy of advanced stage (III-IVA) thymomas. METHODS: From 1989 to 2004, 30 patients with Masaoka stage III and IVA thymomas underwent neoadjuvant chemotherapy, surgery, and postoperative radiotherapy. The neoadjuvant and adjuvant chemotherapy consisted of three courses of cisplatin, epidoxorubicin, and etoposide every 3 weeks. Adjuvant radiotherapy consisted of 45 Gy for complete resections or 60 Gy for incomplete resections. RESULTS: The preoperative diagnosis of invasive thymomas was obtained for 16 patients: five by mediastinotomy, seven by video-assisted thoracic surgery, and four by fine needle aspiration. For 14 patients, no histological diagnosis was available, but a thymus-related syndrome was present in all.Twenty-seven patients are still alive (25 disease-free) and three have died (one disease-free). The 10-year survival rates were 85.7% and 76.1% for stage III and IVA thymomas, respectively (difference not significant). Only the World Health Organization pathological diagnosis significantly affected the survival, with type B3 having a worse prognosis than type AB, B1, and B2 thymomas (p = 0.02). CONCLUSION: The multimodality treatment of stage III and IVA thymomas by means of neoadjuvant chemotherapy provides good long-term outcomes in both stages of the disease.

Advanced stage thymomas and thymic carcinomas: results of multimodality treatments.

BACKGROUND: With the aim of evaluating the results of multidisciplinary approaches, we reviewed our experience in multimodality treatment of advanced stage (III and IVA) thymic tumors. METHODS: From 1976 to 2003, 56 patients with Masaoka stage III and IVA thymic tumors underwent a multimodality treatment. Thirty-six patients underwent neoadjuvant chemotherapy, surgery, and postoperative radiotherapy; 20 patients were treated by primary surgery and postoperative radiotherapy (n = 12), chemotherapy (n = 1) or chemoradiotherapy (n = 7). The neoadjuvant or adjuvant chemotherapy consisted of three courses of cisplatin, epidoxorubicin, and etoposide every 3 weeks. Adjuvant radiotherapy consisted of 45 Gy for complete resections or 60 Gy for incomplete resections. RESULTS: The preoperative diagnosis of invasive thymomas was performed in a total of 29 cases: 15 by mediastinotomy, 6 by video-assisted thoracoscopic surgery, and 8 by fine-needle aspiration. In 27 cases no diagnosis was available, but in most of them a thymus-related syndrome was present. Thirty-four patients are still alive (31 disease-free), and 22 have died (2 disease-free). Ten-year survival was 48% and 45.7% for stage III and IVA thymomas, respectively. The presence of myasthenia gravis (p = 0.04) and neoadjuvant chemotherapy (p = 0.004) affected survival significantly. CONCLUSIONS: The multimodality treatment of stage III and IVA thymic tumors allows a good long-term outcome; the neoadjuvant chemotherapy improves the resectability rate and the survival of both stages of the disease.

Radiofrequency ablation of lung malignancies: where do we stand?

Percutaneous radiofrequency (RF) ablation is a minimally invasive technique used to treat solid tumors. Because of its ability to produce large volumes of coagulation necrosis in a controlled fashion, this technique has gained acceptance as a viable therapeutic option for unresectable liver malignancies. Recently, investigation has been focused on the clinical application of RF ablation in the treatment of lung malignancies. In theory, lung tumors are well suited to RF ablation because the surrounding air in adjacent normal parenchyma provides an insulating effect, thus facilitating energy concentration within the tumor tissue. Experimental studies in rabbits have confirmed that lung RF ablation can be safely and effectively performed via a percutaneous, transthoracic approach, and have prompted the start of clinical investigation. Pilot clinical studies have shown that RF ablation enables successful treatment of relatively small lung malignancies with a high rate of complete response and acceptable morbidity, and have suggested that the technique could represent a viable alternate or complementary treatment method for patients with non-small cell lung cancer or lung metastases of favorable histotypes who are not candidates for surgical resection. This article gives an overview of lung RF ablation, discussing experimental animal findings, rationale for clinical application, technique and methodology, clinical results, and complications.

Systemic melanoma metastatic to the retina and vitreous.

PURPOSE: Report of a case of retinal and vitreous metastases of a systemic melanoma, possibly arising in the lung, that responded favourably to radiotherapy. CASE REPORT: Retinal and vitreous metastases were demonstrated in a 57-year-old woman during routine follow-up after surgical resection of a melanoma presumed to be a primary pulmonary melanoma. After a 7-week observation period, which confirmed the progressive nature of the intra-ocular lesions, the patient was treated by external beam radiotherapy at a dose of 35 Gy delivered in 14 fractions of 2.5 Gy. Complete disappearance of the vitreous invasion and progressive elimination of the retinal invasion were observed over a period of 9 months. Final visual function was 20/25. REVIEW OF PUBLISHED CASES: A review of the literature identified 28 cases of melanoma with metastases to the retina and vitreous. In almost all of these cases, the primary tumour was a cutaneous melanoma and the mean patient survival following the diagnosis of intra-ocular metastases was 22 months. Retinal metastases, as in the case reported here, present a vascular tropism and tend to develop around veins. These metastases are generally unilateral and may be either solitary or multiple. Tumour invasion of the vitreous occurred by means of isolated cells forming a suspension of aggregates or spherules. Vitreous haemorrhage and irreducible neovascular glaucoma leading to functional impairment, which requires enucleation, were both the most frequent and the most serious complications of these metastases. Treatment is always palliative and is effective in cases with limited retinal and vitreous invasion, as in the case reported here. CONCLUSIONS: Metastatic melanoma in the retina and vitreous is a rare entity and can lead to functional impairment and enucleation because of neovascular glaucoma. As treatment is only effective in cases with limited invasion, systematic screening is recommended in all patients with a metastatic cutaneous melanoma presenting with suggestive ocular symptoms.

Comparative distribution of azithromycin in lung tissue of patients given oral daily doses of 500 and 1000 mg.

OBJECTIVES: The administration of antibacterial agents should be optimized on the basis of their distribution to enhance drug exposure and obtain bacterial eradication. This study examines the pharmacokinetics of azithromycin in plasma, lung tissue and bronchial washing in patients after oral administration of 500 mg versus 1000 mg once daily for 3 days. PATIENTS AND METHODS: Samples of plasma, lung tissue and bronchial washing were obtained from a cohort of 48 patients during open-chest surgery for lung resection up to 204 h after the last drug dose, and assayed for antibiotic concentrations. RESULTS: Azithromycin was widely distributed within the lower respiratory tract and sustained levels of the drug were detectable at the last sampling time in lung tissue. Doubling the dose of the antibiotic resulted in a proportional increase in lung area under the curve (AUC, 1245.4 versus 2514.2 h x mg/kg) and peak tissue concentration (Cmax, 8.93 +/- 2.05 versus 18.6 +/- 2.20 mg/kg). The pharmacodynamic parameter AUC/MIC for susceptible and intermediate strains of Streptococcus pneumoniae (MICs 0.5 and 2 mg/L, respectively) increased after administration of the 1000 mg schedule compared with 500 mg (AUC/MIC0.5 2414 versus 1144 and AUC/MIC2 2112 versus 814.1 h x mg/kg, respectively) in pulmonary tissue. CONCLUSIONS: Lung exposure to azithromycin is increased proportionally by doubling the dose, which results in a predictable pharmacokinetic behaviour of the drug in the lower respiratory tract.