Characterisation of Bacteriophage vB_SmaM_Ps15 Infective to Stenotrophomonas maltophilia Clinical Ocular Isolates

Recent acknowledgment that multidrug resistant Stenotrophomonas maltophilia strains can cause severe infections has led to increasing global interest in addressing its pathogenicity. While being primarily associated with hospital-acquired respiratory tract infections, this bacterial species is also relevant to ophthalmology, particularly to contact lens-related diseases. In the current study, the capacity of Stenotrophomonas phage vB_SmaM_Ps15 to infect ocular S. maltophilia strains was investigated to explore its future potential as a phage therapeutic. The phage proved to be lytic to a range of clinical isolates collected in Australia from eye swabs, contact lenses and contact lens cases that had previously shown to be resistant to several antibiotics and multipurpose contact lenses disinfectant solutions. Morphological analysis by transmission electron microscopy placed the phage into the Myoviridae family. Its genome size was 161,350 bp with a G + C content of 54.2%, containing 276 putative protein-encoding genes and 24 tRNAs. A detailed comparative genomic analysis positioned vB_SmaM_Ps15 as a new species of the Menderavirus genus, which currently contains six very similar globally distributed members. It was confirmed as a virulent phage, free of known lysogenic and pathogenicity determinants, which supports its potential use for the treatment of S. maltophilia eye infections.     

Small-scale pattern formation in a cortical area of the embryonic chicken telencephalon

The parahippocampal area is a cortical region of the avian dorsomedial telencephalon. In the chicken embryo, it contains discrete clusters of cadherin-7-positive cells, which are embedded in a cadherin-7-negative matrix. In the present work, the development and spatial distribution of these clusters is studied in whole-mount specimens. The clusters form a complex, coherent pattern of patches of variable size, spacing, and staining intensity. The pattern is especially prominent and regularly spaced in the rostral part of the caudolateral parahippocampal area. Here, it consists of stripes and connecting bridges with an average periodicity of approximately 0.3 mm. This pattern vaguely resembles some animal fur patterns and the ocular dominance domain of the mammalian visual cortex. The cadherin-7-positive patches also differ from their surrounding area by their cytoarchitecture and their increased acetylcholinesterase activity, suggesting that they represent functionally specialized subregions within the parahippocampal area. During development, the patchiness is first observed between 9 and 10 days of incubation and gradually becomes more prominent until 15 days of incubation. Our results indicate that the patchy organization of cortical gray matter on a small scale of periodicity (below 1 mm), which is well studied in the mammalian neocortex, is also found in the avian telencephalon.     

Prevalence of psychotic comorbidity in combat-related post-traumatic stress disorder

OBJECTIVE: We explored the prevalence of comorbidity of psychotic symptoms among Croatian war veterans with combat-related post-traumatic stress disorder (PTSD) and the psychotic features among these patients, as well as the association between psychotic symptoms and personality disorders. METHODS: The study included 680 men who had experienced combat stress and had diagnoses of PTSD confirmed before examination. They were compared with a group of 289 soldiers with combat experience under regular medical examination, who were still in active military service. The groups were matched in duration of combat experience, time elapsed between combat experience and the study, age, marital status, and education. Statistical analyses were performed using the t test and chi2 test. RESULTS: The study showed that 15% of war veterans had current chronic PTSD and 45% had PTSD with one or more comorbid diagnoses. Psychotic disorders with PTSD were confirmed for 17% of those patients and major depressive disorder with psychotic features for 15%. Depression and psychotic symptoms were more often found among patients without personality disorders. Also, we found that 9% of the war veterans who were still in active military service had some psychiatric disorders. CONCLUSIONS: Many patients demonstrated psychotic symptoms different from flashbacks and dissociative symptoms. Those psychotic symptoms are an integral part of PTSD and have a symbolic relation to the trauma.     

Hypersensitivity to pollen allergens on the Adriatic coast

This paper describes a study of air concentrations of pollens and a calendar of pollination around the town of Split on the Croatian Adriatic in 1994. High pollen concentrations of Parietaria officinalis dominated during the year (up to 20% from April to June) followed by the pollens of Pistacia lentiscus, Olea europaea, Pinus halepensis, Juniperus oxycedrus, Acacia baileyana, Artemisia vulgaris, Ambrosia elatior and Cistus monspeliensis. In 1994-95, skin prick tests using commercially available standard inhalation allergens and specially prepared pollen allergens were performed on 3,500 patients with allergic respiratory symptoms. About 30% were allergic to standard pollen allergens (mixed grass pollen, mixed tree pollen, Parietaria officinalis and Pittosporum tobira). Hypersensitivity to more than one allergen was found in 45% of patients, whereas 15% did not react to any of the standard allergens. Additional testing with newly prepared individual allergens (P. lentiscus, O. europaea, P. halepensis, A. baileyana, C. monspeliensis, A. vulgaris, A. elatior) revealed hypersensitivity in a number of patients, but 36% showed no reaction. This finding suggests that further studies of this kind are needed for additional identification, isolation, and characterisation of pollen allergens that are present in the Adriatic coast.     

Development of an HPLC method for the determination of ranitidine and cimetidine in human plasma following SPE

A selective, sensitive and accurate high-performance liquid chromatographic method has been developed, validated and applied for the determination of ranitidine and cimetidine in plasma samples. The effects of mobile phase composition, buffer concentration, mobile phase pH and concentration of organic modifiers on retention of investigated drugs were investigated. Sample preparation was carried out by adding an internal standard, famotidine, and the clean-up procedure was accomplished using solid-phase extraction (SPE). This method uses ultraviolet detection, the separation used a Lichrocart Lichrospher 60 RP-select B column and the mobile phase consisted of 0.2% triethylamine (TEA), 0.04 mol l(-1) KH2PO4 at pH 6.8 and 14% acetonitrile. The recovery, selectivity, linearity, precision and accuracy of the method were evaluated from spiked human plasma. The method has been implemented to monitor ranitidine levels in clinical samples.     

Changes in articular cartilage and subchondral bone histomorphometry in osteoarthritic knee joints in humans

In this study, we have examined the correlation between the histological and histochemical changes of articular cartilage and bone parameters of the underlying subchondral bone. The aim was to elucidate patterns of bone parameter changes within different depths of subchondral bone in the joints with macroscopically normal cartilage and in joints with osteoarthritis (OA). Ten tibial plateaus were taken from patients during total knee replacement surgery due to severe OA. They were compared with 10 sets of tibial condyles obtained from autopsy subjects with no history of bone or joint disease. The cylindrical cartilage-bone samples were taken out from the anterior, posterior, external, and internal areas of the condyles for cartilage assessment (Mankin score) and subchondral bone histomorphometry. Four histomorphometric parameters were measured: bone volume (BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), and trabecular separation (Tb.S). Our study showed that subchondral bone from the OA group had significantly higher bone volume (54.1 +/- 10.6%) than control group (37.8 +/- 8.1%) (P < 0.01). In addition, trabecular parameters from the OA subchondral bone showed a smaller number of sparsely distributed and thicker trabecules than in control group (P < 0.05). Medial and lateral condyle from the control group did not differ significantly, while medial condyle from OA group showed a high increase of bone volume (62.8 +/- 13.3) and consecutively different trabecular parameters when compared with the lateral condyle from the same group. Also, it was shown that there are regional differences (anterior, posterior, internal, and external) in bone parameters between both condyles within both, control and OA groups. Comparison of bone parameters from three different stage of articular cartilage degeneration (Mankin score) showed that higher degree of cartilage degeneration is followed by significant changes in subchondral bone architecture. Furthermore, we have found that progression of cartilage degeneration leads to changes in bone parameters which affected deeper levels of subchondral bone. According to these results, it can be suggested that changes in histomorphometric parameters of subchondral bone are secondary to cartilage damage and proceed deeper into subchondral bone with increasing cartilage degeneration.