Serum Level of Protein-Bound Uraemic Toxins in Haemodialysis Patients with Chronic Kidney Disease-Associated Pruritus: Myths and Facts

Recent studies place great importance on Protein-Bound Uraemic Toxins (PBUT) in the context of etiopathogenesis of chronic kidney disease-associated pruritus (CKD-aP). This study aimed to investigate the possible contribution of free and total Indoxyl Sulfate (IS) and p-Cresol Sulfate (PCS) to the cause of CKD-aP. Group A included 64 patients on maintenance haemodialysis (HD) with CKD-aP. Group B included 62 patients on maintenance HD that did not report CKD-aP, and group C included 50 healthy controls. Pruritus severity was assessed using a Numerical Rating Scale (NRS). Moreover, other tools like UP-Dial, ItchyQoL, and the 4-Item Itch Questionnaire evaluating CKD-aP were completed by the patients. The serum levels of free and total IS and PCS concentrations were measured using the Ultra Performance Liquid Chromatography System. No significant difference in the serum level of free and total IS, or PCS, was observed between the patients who reported CKD-aP and those without pruritus. Moreover, there was no correlation between serum IS or PCS levels and the severity of the itch. Our study does not support earlier findings about higher levels of IS and PCS in patients reporting CKD-aP. Further studies will be needed to investigate these discrepancies as well as to understand the cause of CKD-aP.

Effect of Obstructive Sleep Apnea and CPAP Treatment on the Bioavailability of Erythrocyte and Plasma Nitric Oxide

INTRODUCTION

Endothelial dysfunction resulting from decreased nitric oxide (NO) bioavailability is an important mechanism that increases cardiovascular risk in subjects with obstructive sleep apnea (OSA). NO is produced by nitric oxide synthase (NOS) in a reaction that converts L-arginine to L-citrulline. Asymmetric-dimethylarginine (ADMA) is created by L-arginine and is a naturally occurring competitive inhibitor of nitric oxide synthase (NOS). The aim of our study was to verify if erythrocytes could play a role in the storage and accumulation of ADMA in OSA patients. The crosstalk between erythrocyte-ADMA, SDMA, L-arginine, and L-citrulline levels and endothelial function was investigated in OSA subjects both at baseline and prospectively following 1-year CPAP (continuous positive airway pressure) treatment.

MATERIAL AND METHODS

A total of 46 subjects with OSA were enrolled in this study and divided into two groups: those with moderate-to-severe OSA and those with mild or no OSA. A physical examination was followed by blood collection for the assessment of biochemical cardiovascular risk factors and the nitric oxide bioavailability parameters both in plasma and erythrocytes. Vasodilative endothelial function was assessed using Laser Doppler Flowmetry (LDF).

RESULTS

No significant changes regarding the NO pathway metabolites were noted apart from the plasma L-citrulline concentration, which was decreased in patients with OSA (26.9 ± 7.4 vs. 33.1 ± 9.4 μM, p < 0.05). The erythrocyte ADMA concentration was lower than in plasma irrespective of the presence of OSA (0.33 ± 0.12 vs. 0.45 ± 0.08 μM in OSA, p < 0.05 and 0.33 ± 0.1 vs. 0.45 ± 0.07 μM in the control, p < 0.05). No significant changes regarding the LDF were found. CPAP treatment did not change the levels of NO metabolites in the erythrocytes.

CONCLUSIONS

The erythrocyte pool of the NO metabolic pathway intermediates does not depend on OSA and its treatment, whereas the erythrocytes could constitute a high-volume buffer in their storage Hence, the results from this prospective study are a step forward in understanding the role of the erythrocyte compartment and the intra-erythrocyte pathways regulating NO bioavailability and paracrine endothelial function in the hypoxia-reoxygenation setting, such as obstructive sleep apnea.

Nephrotic Syndrome – Different Risk of Venous Thromboembolism with Different Approaches to Justify Prophylactic Anticoagulation

All of the circumstances influencing any of the elements of Virchow’s Triad can increase the risk of venous thromboembolism. Assessing prothrombotic factors can sometimes be difficult. One of the examples of such a condition is nephrotic syndrome. In this condition at least two elements of Virchow’s triad are affected: physiological blood composition and the venous blood flow which is slowed down by the edema. Except for the cases mentioned in KDIGO (Kidney Disease: Improving Global Outcomes), the use of anticoagulant drugs in the prophylaxis of VTE (Venous Thromboembolism) in nephrotic syndrome seems unclear. Nevertheless, due to the increased risk of VTE, it is worth implementing mechanical anticoagulant prophylaxis, which can also improve the quality of life of patients by reducing swelling. The article analyzes the current knowledge on the field and gives some proposals with low bleeding risk.

Measurement of Serum Levels of 5 Amino Acids and Dimethylamine Using Liquid Chromatography-Tandem Mass Spectrometry in Patients without Septic Associated Acute Kidney Injury and with Septic Associated Acute Kidney Injury Requiring Continuous Renal Replacement Therapy

Background

Acute kidney injury (AKI) is one of the most common organ failures. An early diagnosis of AKI using specific biomarkers is essential for effective treatment. This study determined the serum concentrations of selected amino acids and amines using targeted liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) in patients with AKI during sepsis and septic shock treated in the Intensive Care Unit (ICU).

Material/Methods

A sample of 41 patients was divided into 2 groups: (1) patients with sepsis and septic shock along required continuous renal replacement therapy (CRRT) due to AKI (n=13), and (2) patients with sepsis and septic shock but without AKI (n=28). LC-MS/MS was used to measure a serum concentration of 6 amino acids and amines: arginine, ornithine, asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), dimethylamine (DMA), and citrulline.

Results

There was a statistically significantly higher median DMA level in AKI patients compared to those without AKI (8.1 vs 5.2 umol/L; P=0.022). The results for the remaining molecules showed no significant differences (P>0.05). Patients with DMA ≥14.95 umol/L (n=5; 100%) and treated with CRRT presented DMA level below the cut-off point (n=7; 20%). Subjects with creatinine levels ≥1.19 mg/dL (n=11; 28%) and treated with CRRT presented creatinine levels below the cut-off point (n=1; 3%).

Conclusions

In patients with sepsis, increased serum levels of DMA were significantly associated with AKI requiring CRRT. It remains unclear whether increased DMA concentrations are secondary to sepsis-induced AKI or are a cause.

Changes in the Plasma and Platelet Nitric Oxide Biotransformation Metabolites during Ischemic Stroke-A Dynamic Human LC/MS Metabolomic Study

Despite improvement in the management of modifiable cardiovascular risk factors, ischemic stroke remains the leading cause of morbidity and mortality in the adult population. The aim of this study was to analyze the time-dependent dynamic differences in expression of the nitric oxide (NO) metabolic pathway in the platelet and plasma compartment between subjects with and without ischemic stroke. Additionally, the interplay between these parameters and platelet aggregation was investigated. A total of 418 patients in acute phase of non-cardioembolic stroke were investigated. Following the inclusion and exclusion criteria, finally 40 subjects with stroke and 39 demographically matched healthy participants were enrolled. Neurological physical examination, followed by assessment of the platelet and plasma levels of the nitric oxide synthase (NOS) inhibitors, including asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA), as well as NOS substrate-L-Arginine were performed dynamically three times within the first 24-h, then on the 3rd and 7th day after the stroke onset, which was compared with the healthy control. The platelet L-Arginine concentration was significantly higher on the 1st and 3rd day of stroke, while the plasma levels were significantly lower on exact days in comparison to the control. The competitive NOS-inhibitors in platelets were stably elevated in stroke subjects, whereas no significant differences in plasma compartment were noted. The arachidonic-acid-induced platelet aggregation was negatively associated with the platelet NOS substrate bioavailability, as assessed by the L−Arginine ADMA-ratio on the 3rd and 7th day. Subjects with non-cardioembolic ischemic stroke are characterized by elevated platelet levels of NOS inhibitors. Management of stroke results in increasing the platelet L-Arginine concentration and subsequent NO bioavailability in the platelet compartment.

A computationally designed β-amino acid-containing miniprotein

A new miniprotein built from three helices, including one structure based on the ααβαααβ sequence pattern was developed. Its crystal structure revealed a compact conformation with a well-packed hydrophobic core of unprecedented structure. The miniprotein formed dimers that were stabilized by the interaction of their hydrophobic surfaces.

Altered L-Arginine Metabolic Pathways in Gastric Cancer: Potential Therapeutic Targets and Biomarkers

There is a pressing need for molecular targets and biomarkers in gastric cancer (GC). We aimed at identifying aberrations in L-arginine metabolism with therapeutic and diagnostic potential. Systemic metabolites were quantified using mass spectrometry in 293 individuals and enzymes’ gene expression was quantified in 29 paired tumor-normal samples using qPCR and referred to cancer pathology and molecular landscape. Patients with cancer or benign disorders had reduced systemic arginine, citrulline, and ornithine and elevated symmetric dimethylarginine and dimethylamine. Citrulline and ornithine depletion was accentuated in metastasizing cancers. Metabolite diagnostic panel had 91% accuracy in detecting cancer and 70% accuracy in differentiating cancer from benign disorders. Gastric tumors had upregulated NOS2 and downregulated ASL, PRMT2, ORNT1, and DDAH1 expression. NOS2 upregulation was less and ASL downregulation was more pronounced in metastatic cancers. Tumor ASL and PRMT2 expression was inversely related to local advancement. Enzyme up- or downregulation was greater or significant solely in cardia subtype. Metabolic reprogramming in GC includes aberrant L-arginine metabolism, reflecting GC subtype and pathology, and is manifested by altered interplay of its intermediates and enzymes. Exploiting L-arginine metabolic pathways for diagnostic and therapeutic purposes is warranted. Functional studies on ASL, PRMT2, and ORNT1 in GC are needed.

Sitagliptin Modulates Oxidative, Nitrative and Halogenative Stress and Inflammatory Response in Rat Model of Hepatic Ischemia-Reperfusion

A possibility of repurposing sitagliptin, a well-established antidiabetic drug, for alleviating injury caused by ischemia-reperfusion (IR) is being researched. The aim of this study was to shed some light on the molecular background of the protective activity of sitagliptin during hepatic IR. The expression and/or concentration of inflammation and oxidative stress-involved factors have been determined in rat liver homogenates using quantitative RT-PCR and Luminex^® xMAP^® technology and markers of nitrative and halogenative stress were quantified using targeted metabolomics (LC-MS/MS). Animals (n = 36) divided into four groups were treated with sitagliptin (5 mg/kg) (S and SIR) or saline solution (C and IR), and the livers from IR and SIR were subjected to ischemia (60 min) and reperfusion (24 h). The midkine expression (by 2.2-fold) and the free 3-nitrotyrosine (by 2.5-fold) and IL-10 (by 2-fold) concentration were significantly higher and the Nox4 expression was lower (by 9.4-fold) in the IR than the C animals. As compared to IR, the SIR animals had a lower expression of interleukin-6 (by 4.2-fold) and midkine (by 2-fold), a lower concentration of 3-nitrotyrosine (by 2.5-fold) and a higher Nox4 (by 2.9-fold) and 3-bromotyrosine (by 1.4-fold). In conclusion, IR disturbs the oxidative, nitrative and halogenative balance and aggravates the inflammatory response in the liver, which can be attenuated by low doses of sitagliptin.

Low metformin dose and its therapeutic serum concentration in prediabetes

This prospective study aimed to analyze whether the patients with pre-diabetes (pre-DM) reach the TC (therapeutic concentration) of the metformin during repeated, low, constant drug dose. The guidelines do not recommend any metformin dose for this group of patients. Based on the previous study after a dose of 1700 mg/day the patients seem to reach the therapeutic drug concentration, which guarantees the glycemic effect. Twenty patients with new-diagnosed pre-DM were treated with a 1500 mg/day regimen of the metformin for 15 weeks. The serum concentration of the drug was assessed by liquid chromatography-mass spectrometry technique at 6 and 15 week of the treatment. The correlation of the serum metformin concentration with BMI (body mass index) and patients' weight was also performed. The mean metformin concentration was: 4.65 μmol/L (± 2.41) and 5.41 μmol/L (± 3.44) (p = 0.27) after 6 and 15 weeks of the treatment respectively. There was a positive correlation between the serum concentration of the metformin and body weight (but not BMI) in the 15th week of the therapy (p = 0.04)- the higher body weight the higher concentration of the metformin. Patients with pre-diabetes can be successfully treated with a low dose of metformin, to reach the drug's therapeutic concentration. Body weight can impact the metformin serum concentration during long-term treatment what should be taken into consideration when choosing the dose because of its pleiotropic effect e.g. on the cardiovascular system via reduction of the oxidative stress and would be not connected with the drug's hypoglycemic effect.ClinicalTrials.gov number: NCT03398356; date of first registration: 01/07/2018.

Metformin has no impact on nitric oxide production in patients with pre-diabetes

AIMS/INTRODUCTION

The authors evaluated the impact of different dose of metformin on NO (nitric oxide) production in subjects with pre-diabetes.

MATERIALS AND METHODS

The metformin-naïve patients from one Diabetic Center with newly diagnosed pre-diabetes, without cardio-vascular diseases, were randomized (based on the identification number, individual for each inhabitant in the country) for treatment with different doses of metformin (group A 3 × 500 mg, group B 3 × 1000 mg) for 12 weeks. Then, the subjects from group B were switched to dose 3 × 500 for the last 3 weeks. The wide panel of L-arginine/NO pathway metabolites concentrations was assessed using the liquid chromatography-mass spectrometry technique.

RESULTS

Between October 2017 and December 2018, 36 individuals were initially randomized to intervention groups. The study was completed with 25 subjects: 14 patients in group A, 11 in group B; also 11 healthy volunteers were recruited. There was no difference between participants with pre-diabetes and healthy volunteers as regards the baseline characteristics except for fasting glucose and fatty liver. The decrease of L-citrulline concentration only was reported for treatment groups during the intervention period, with no change for the other NO-production related substances.

CONCLUSION

It was the first study on the in vivo release of NO in humans with different metformin doses in patients with pre-diabetes. Metformin did not seem to increase NO production measured by the citrulline plasma levels, irrespective of the dose. The citrulline concentration change might indicate the drug impact on the condition of the enterocytes.

Sex, Type of Surgery, and Surgical Site Infections Are Associated with Perioperative Cortisol in Colorectal Cancer Patients

Excessive endocrine response to trauma negatively affects patients’ well-being. Cortisol dynamics following robot-assisted colorectal surgery are unknown. We aimed at determining the impact of cancer pathology and surgery-related factors on baseline cortisol levels and analyzed its time-profile in colorectal cancer patients undergoing open or robot-assisted surgery. Cortisol levels were measured using liquid chromatography quadrupole time-of-flight mass spectrometry. Baseline cortisol was not associated with any patient- or disease-related factors. Post-surgery cortisol increased by 36% at 8 h and returned to baseline on postoperative day three. The cortisol time profile was significantly affected by surgery type, estimated blood loss, and length of surgery. Baseline-adjusted cortisol increase was greater in females at hour 8 and in both females and patients from open surgery group at hour 24. Solely in the open surgery group, cortisol dynamics paralleled changes in interleukin (IL)-1β, IL-10, IL-1ra, IL-7, IL-8 and tumor necrosis factor (TNF)-α but did not correlate with changes in IL-6 or interferon (IFN)-γ at any time-point. Cortisol co-examined with C-reactive protein was predictive of surgical site infections (SSI) with high accuracy. In conclusion, patient’s sex and surgery invasiveness affect cortisol dynamics. Surgery-induced elevation can be reduced by minimally invasive robot-assisted procedures. Cortisol and C-reactive protein as SSI biomarkers might be of value in the evaluation of safety of early discharge of patients.

The impact of Sample Handling Time on metformin serum concentration

This is an informative article which can help research providers to arrange and conduct studies dedicated to the assessment of metformin serum concentrations. If there is a problem with coordination of sample preparation and it is necessary to measure metformin concentration, two hours gap between blood drain and centrifugation has no impact on the results.

L-Arginine/Nitric Oxide Pathway Is Altered in Colorectal Cancer and Can Be Modulated by Novel Derivatives from Oxicam Class of Non-Steroidal Anti-Inflammatory Drugs

L-arginine/nitric oxide pathway metabolites are altered in colorectal cancer (CRC). We evaluated underlying changes in pathway enzymes in 55 paired tumor/tumor-adjacent samples and 20 normal mucosa using quantitative-PCR and assessed the impact of classic and novel oxicam analogues on enzyme expression and intracellular metabolite concentration (LC-MS/MS) in Caco-2, HCT116, and HT-29 cells. Compared to normal mucosa, ARG1, PRMT1, and PRMT5 were overexpressed in both tumor and tumor-adjacent tissue and DDAH2 solely in tumor-adjacent tissue. Tumor-adjacent tissue had higher expression of ARG1, DDAH1, and DDAH2 and lower NOS2 than patients-matched tumors. The ARG1 expression in tumors increased along with tumor grade and reflected lymph node involvement. Novel oxicam analogues with arylpiperazine moiety at the thiazine ring were more effective in downregulating DDAHs and PRMTs and upregulating ARG2 than piroxicam and meloxicam. An analogue distinguished by propylene linker between thiazine's and piperazine's nitrogen atoms and containing two fluorine substituents was the strongest inhibitor of DDAHs and PRMTs expression, while an analogue containing propylene linker but no fluorine substituents was the strongest inhibitor of ARG2 expression. Metabolic reprogramming in CRC includes overexpression of DDAHs and PRMTs in addition to ARG1 and NOS2 and is not restricted to tumor tissue but can be modulated by novel oxicam analogues.

Esophageal Squamous Cell Carcinoma Is Accompanied by Local and Systemic Changes in L-arginine/NO Pathway

The L-arginine/NO pathway holds promise as a source of potential therapy target and biomarker; yet, its status and utility in esophageal squamous cell carcinoma (ESCC) is unclear. We aimed at quantifying pathway metabolites in sera from patients with ESCC (n = 61) and benign conditions (n = 62) using LC-QTOF-MS and enzyme expression in esophageal tumors and matched noncancerous samples (n = 40) using real-time PCR with reference to ESCC pathology and circulating immune/inflammatory mediators, quantified using Luminex xMAP technology. ESCC was associated with elevated systemic arginine and asymmetric dimethylarginine. Citrulline decreased and arginine bioavailability increased along with increasing ESCC advancement. Compared to adjacent tissue, tumors overexpressed ODC1, NOS2, PRMT1, and PRMT5 but had downregulated ARG1, ARG2, and DDAH1. Except for markedly higher NOS2 and lower ODC1 in tumors from M1 patients, the pathology-associated changes in enzyme expression were subtle and present also in noncancerous tissue. Both the local enzyme expression level and systemic metabolite concentration were related to circulating inflammatory and immune mediators, particularly those associated with eosinophils and those promoting viability and self-renewal of cancer stem cells. Metabolic reprogramming in ESCC manifests itself by the altered L-arginine/NO pathway. Upregulation of PRMTs in addition to NOS2 and ODC1 and the pathway link with stemness-promoting cytokines warrants further investigation.

Distinct Local and Systemic Molecular Signatures in the Esophageal and Gastric Cancers: Possible Therapy Targets and Biomarkers for Gastric Cancer

Gastric (GC) and esophageal (EC) cancers are highly lethal. Better understanding of molecular abnormalities is needed for new therapeutic targets and biomarkers to be found. Expression of 18 cancer-related genes in 31 paired normal-tumor samples was quantified by reversely-transcribed quantitative polymerase chain reaction (RTqPCR) and systemic concentration of 27 cytokines/chemokines/growth factors in 195 individuals was determined using Luminex xMAP technology. Only Ki67, CLDN2, and BCLxL were altered in GC while Ki67, CDKN1A, ODC1, SLC2A1, HIF1A, VEGFA, NOS2, CCL2, PTGS2, IL10, IL10Ra, and ACTA2 were changed in EC. The relatively unaltered molecular GC landscape resulted from high expression of BCLxL, CDKN1A, BCL2, Ki67, HIF1A, VEGFA, ACTA2, TJP1, CLDN2, IL7Ra, ODC1, PTGS2, and CCL2 in non-cancerous tissue. The NOS2 expression and IL-4, IL-9, FGF2, and RANTES secretion were higher in cardiac than non-cardiac GC. Four-cytokine panels (interleukin (IL)-1β/IL-1ra/IL-6/RANTES or IL-1β/IL-6/IL-4/IL-13) differentiated GC from benign conditions with 87–89% accuracy. Our results showed increased proliferative, survival, inflammatory and angiogenic capacity in gastric tumor-surrounding tissue, what might contribute to GC aggressiveness and facilitate cancer recurrence. Further studies are needed to determine the CLDN2 and NOS2 suitability as candidate molecular targets in GC and cardiac GC, respectively, and discern the role of CLDN2 or to verify IL-1β/IL-1ra/IL-6/RANTES or IL-1β/IL-6/IL-4/IL-13 usefulness as differential biomarkers.

Interleukins 4 and 13 and Their Receptors Are Differently Expressed in Gastrointestinal Tract Cancers, Depending on the Anatomical Site and Disease Advancement, and Improve Colon Cancer Cell Viability and Motility

Immunosuppressive interleukins (IL)-4 and 13 may directly promote cancer but neither their status nor role in gastrointestinal tract is clarified. We aim at quantifying ILs and their receptors in paired normal-tumor samples (n = 49/51) and sera (n = 263), using immunoassays and RTqPCR, and screening for their effect on colonic cancer cells. Both ILs were elevated locally at protein level in all cancers but only IL13 transcripts in colon were upregulated. Interleukin and their receptor expression reflected cancer pathology to varying degrees, with the association frequently inverse and manifested in non-cancerous tissue. Positive correlation with cancer-promoting genes BCL2, BCLxL, HIF1A, VEGFA, ACTA2, CCL2, PTGS2, and CDKN1A, but not Ki67, was demonstrated, particularly for ILs' receptors. Circulating IL-4 was elevated in all, while IL-13 only in colorectal or esophageal cancers, reflecting their advancement. IL4Ra and IL13Ra1 transcripts were downregulated by hypoxia and, in Caco-2, also by IL-4. Interleukin stimulation slightly improved colonic cancer cell viability, weakly upregulating BCL2 and Ki67 in HCT116 and HT-29. It affected cell motility more markedly and was consistently accompanied by upregulation of claudin-2. Gastrointestinal tract cancers are associated with IL-4 and IL-13 upregulation, which may facilitate cancer growth. Targeting both interleukins as an antineoplastic strategy warrants further investigation.

[Causality relationship of drug adverse reactions: experience in the use of HIV-protease inhibitors]

PURPOSE

To establish the exact cause and effect relationship between protease inhibitors (PIs) and adverse events.

MATERIALS AND METHOD

Prospective, cohort, multicenter study on HIV-positive patients who are beginning treatment with a PI. Causal relationships are evaluated using the RUCAM algorithm.

RESULTS

Since the beginning of the study 1207 patients have been enrolled. Average time of observation is 10.7 months. To date, 784 adverse events have been observed, distributed as follows: excluded 3.8%, improbable 18.5%, possible 41.3%, probable 30.1%, and highly probable 6.3%. Saquinavir shows a statistically significant difference in the rate of non-correlated events with respect to other groups.

CONCLUSIONS

Over 20% of adverse events during PI treatment are shown to be non-correlated to these drugs. Saquinavir shows the highest rate of non-correlated events.

Incidence of adverse reactions in HIV patients treated with protease inhibitors: a cohort study. Coordinamento Italiano Studio Allergia e Infezione da HIV (CISAI) Group

OBJECTIVE

To assess the probability that protease inhibitor (PI) therapy might be discontinued because of adverse events (AE) and to evaluate the incidence rate of adverse reactions during PI treatment.

DESIGN

A prospective cohort, multicenter study on HIV-positive patients starting treatment with at least one PI.

SETTING

Ten departments of infectious diseases in Northern Italy.

PATIENTS

A total of 1207 patients who started PI therapy in September 1997 and were consecutively observed up to April 1999.

MAIN OUTCOME MEASURES

Adverse reactions following initiation of PI therapy, and time to therapy discontinuation due to AE.

RESULTS

During the study period, 35.9% patients presented adverse reactions of any grade, whereas 9.7% presented at least one serious AE. After 12 months of treatment, the percentage of patients who had interrupted treatment was 36% of ritonavir-treated patients, 14.2% of those treated with indinavir, 13.6% of ritonavir-saquinavir hard gel capsules (HGC)-treated patients, and 8.5% and 2.1%, respectively, for those treated with nelfinavir and saquinavir HGC. Women and patients with hepatitis experienced a significantly greater number of adverse events compared with other categories. Gastrointestinal events were more frequently observed in patients treated with either ritonavir alone or in combination with saquinavir HGC, as well as in patients receiving nelfinavir, although in this group serious events were rare. Here again, neurologic, metabolic, and hepatic toxicity occurred more frequently in ritonavir and ritonavir-saquinavir HGC treated patients. Allergic reactions were more often observed in patients receiving nelfinavir. Indinavir-treated patients presented the highest incidence of renal toxicity.

CONCLUSION

Ritonavir is the drug associated with the largest number of reactions, which appear during the first few months of treatment. Saquinavir HGC and nelfinavir are the best tolerated drugs in a clinical setting.

Influence of arbuscular mycorrhizae and phosphate fertilization on shoot apical growth of micropropagated apple and plum rootstocks

We studied the effects of phosphate fertilization and inoculation with the arbuscular mycorrhizal fungi Glomus mosseae (Nicol. and Gerd.) Gerdmann and Trappe, Glomus intraradices Schenck and Smith or Glomus viscosum Nicolson on shoot apical growth of plantlets that had been micropropagated from MM 106 apple (Malus pumila L.) and Mr.S. 2/5 plum (Prunus cerasifera Ehrh.) rootstocks. Unfertilized and non-mycorrhizal plantlets showed no apical growth during the post in vitro acclimation phase, whereas P fertilization induced early resumption of shoot apical growth. Growth enhancement and percentage of actively growing apices of mycorrhizal-inoculated plantlets were comparable to those obtained in plantlets fertilized with P. Furthermore, tissue P concentrations of mycorrhizal plantlets were similar to those of plantlets fertilized with P. We conclude that mycorrhizal inoculation can be used as a biotechnological tool to overcome blocked apical growth and to reduce chemical inputs, especially P inputs, to micropropagated fruit trees.

Antiepileptic treatment and oculomotor neurons

This report describes the changes of the spontaneous firing rate due to an acute non-toxic dose of phenytoin (PHT), a drug commonly used in antiepileptic therapy, in the pre-motor neurons involved in saccadic movement. The drug (500 mg/kg of a 10% PHT suspension in arabic gum) was orally administered, and plasma and brain levels were regularly evaluated (EMIT assay). Results show that PHT significantly modifies the spontaneous electrical activity of the pre-motor neurons localized in the paramedian pontine reticular formation by inducing excitation, inhibition, or a biphasic effect. PHT action was observed 10-15 min after drug administration, when plasma and brain concentrations were still very low. The oculomotor system neurons appear to be a more specific target to this drug in comparison to the cerebellum and the vestibular system. Since the PHT action was observed 1 hour after drug administration in the vestibular nuclei and the cerebellum, which are extensively connected with the oculomotor neurons, it is possible to hypothesize that PHT can affect the oculomotor neurons directly and, with longer latency, indirectly through the vestibular nuclei and the cerebellum.

Arbuscular mycorrhizal induced changes to plant growth and root system morphology in Prunus cerasifera

We compared root system morphogenesis of micropropogated transplants of Prunus cerasifera L. inoculated with either of the arbuscular mycorrhizal (AM) fungi Glomus mosseae or Glomus intraradices or with the ericoid mycorrhizal species Hymenoscyphus ericae. All plants were grown in sand culture, irrigated with a nutrient solution that included a soluble source of phosphorus, for 75 days after transplanting. Arbuscular mycorrhizal colonization increased both the survival and growth (by over 100%) of transplants compared with either uninoculated controls or transplants inoculated with H. ericae. Arbuscular mycorrhizal colonization increased root, stem and leaf weights, leaf area, root length and specific leaf area, and it decreased root length/leaf area ratio, root/shoot weight ratio and specific root length. Both uptake of phosphorus and its concentration in leaves were increased by AM infection, although the time course of the relationships between intensity of AM infection and P nutrition were complex and suggested a role for factors other than nutrition. The time course for the development of infection varied. It was most rapid with G. mosseae, but it was ultimately higher with G. intraradices. None of the treatments significantly affected the lengths of adventitious roots or the first-, second- or third-order laterals that developed from them. Arbuscular mycorrhizal colonization increased the intensity of branching in all root orders with the effect being most obvious on first-order lateral roots where the number of branches increased from under 100 to over 300 brances m(-1). As a result, although first-order laterals made up 55% of the root systems of control plants, the comparable value was 36% in AM-infected plants. In contrast, second-order laterals represented 25% of control root systems, but 50% of AM-colonized root systems. Glomus intraradices but not G. mosseae increased root diameter. Anatomical studies revealed no changes in the overall form of the root tip, although there were changes in the diameter of the root cap, cell numbers and cell size. Hymenoscyphus ericae increased the duration of the metaphase index. Both AM fungal treatments increased the concentrations of soluble proteins in root extracts and modified the protein profiles by the elimination and addition of protein bands detected by PAGE analysis. We conclude that AM fungal inoculation influenced processes in the root system at different levels, but not all effects were due to improved P nutrition or increased physiological age.

Identification of clinically significant anaerobic bacteria

By combining the various methodologies for anaerobic bacteriology, a scheme has been developed with four flow charts for the identification of the clinically significant anaerobic organisms. This scheme incorporates the use of gas chromatography and a micromethod biochemical system.