Broad-range bacterial and fungal DNA amplification on vitreous humor from suspected endophthalmitis patients

BACKGROUND

Prompt and accurate diagnosis of infectious endophthalmitis is crucial for rapid and effective treatment. By identifying whether the causative pathogen is bacterial or fungal, a rational approach for the use of antibacterials or corticosteroids, respectively, can be followed.

AIM

To assess the clinical utility of broad-range bacterial and fungal DNA amplification in the detection of endophthalmitis (postoperative, posttraumatic, and endogenous).

METHODS

In a prospective study, vitreous humor samples from 70 patients with the clinical diagnosis of presumed endophthalmitis, and from 30 patients undergoing surgery for non-infectious causes, were subjected to routine microbiologic and molecular investigation. DNA extracted from a 50 microL sample was amplified by primers targeting the conserved 16S and 18S ribosomal RNA gene sequences of bacteria and fungi, respectively. Reagents for bacterial DNA amplification were decontaminated of endogenous DNA using 8-methoxypsoralen and long wave UV treatment.

RESULTS AND DISCUSSION

A total of 35 specimens were positive for bacteria or fungi by culture. Of these, Gram-positive organisms were isolated in 19 specimens, Gram-negative organisms in 13 specimens and fungi in 3 specimens. Pseudomonas species, coagulase-negative Staphylococcus, and Streptococcus species were the main etiological agents isolated. Bacterial DNA amplification resulted in 49 positive specimens, compared with 32 positive specimens by culture; and fungal DNA amplification resulted in 11 positive specimens, compared with 3 positive specimens by culture. All control specimens were negative for both culture and DNA amplification.

CONCLUSION

DNA extracted using a single-extraction protocol from 50 microL of vitreous humor and amplified with broad-range bacterial and fungal primers will enable the rapid differentiation (within 14 hours) between bacterial and fungal endophthalmitis and allow tailoring of therapy to individual patients.

Hydrogen-bonding motifs in 4-carboxyphenylammonium nitrate and perchlorate monohydrate, and in bis(4-carboxyphenylammonium) sulfate

In the title compounds, C7H8NO2+.NO3-, (I), C7H8NO2+.ClO4-.H2O, (II), and 2C7H8NO2+.SO4(2-), (III), the carboxyl planes of the 4-carboxyphenylammonium cations are twisted from the aromatic plane. A homonuclear C(8) hydrogen-bonding motif of 4-carboxyphenylammonium cations is observed in both (I) and (II), leading to ;head-to-tail' layers. The cations in (III) form carboxyl group dimers, making a graph-set motif of R2(2)(8). In all the structures, anions connect the cationic layers and an infinite chain running along the c axis is observed, having the C2(2)(6) graph-set motif. Interestingly, in (II), the anions are connected through weak hydrogen bonds involving the water molecules, leading to a graph-set motif of R4(4)(12). Alternate hydrophobic and hydrophilic layers are observed in all three compounds as a result of the column-like arrangement of the aromatic rings of the cations and the anions. Furthermore, in (I), head-to-tail N-H...O interactions and interactions linking the cations and anions form an R6(4)(16) hydrogen-bonding motif, resulting in a pseudo-inversion centre at (1/2, 1/2, 0).

L-Prolinium picrate and 2-methylpyridinium picrate

In the structure of L-prolinium picrate, C5H10NO2+.C6H2N3O7-, the Cgamma atom of the pyrrolidine ring has conformational disorder. Both the major and minor conformers of the pyrrolidine ring adopt conformations intermediate between a half-chair and an envelope. Both the cation and anion are packed through chelated three-centred N-H...O hydrogen bonds. The prolinium cation connects two different picrate anions, leading to an infinite chain running along the b axis. In 2-methylpyridinium picrate, C6H8N+.C6H2N3O7-, the cations and anions are packed separately along the a axis and are interconnected by N-H...O hydrogen bonds. Intramolecular contacts between phenolate O atoms and adjacent nitro groups are identified in both structures. A graph-set motif of R1(2)(6) is observed in both structures.

Pyridoxinium picrate

The title compound [systematic name: 3-hydroxy-4,5-bis(hydroxymethyl)-2-methylpyridinium 2,4,6-trinitrophenolate], C(8)H(12)NO(3)(+)xC(6)H(2)N(3)O(7)(-), is a complex of picric acid with pyridoxine. The asymmetric part of the unit cell contains one pyridoxinium cation and one picrate anion. The aromatic rings of the picrate anion and the pyridoxinium cation are inclined with a dihedral angle of 83.19 (7) degrees . An intramolecular hydrogen bond between OH and a nearby CH(2)OH group is observed in the cation. The hydrophobic layers at y = {1/2} are packed between the hydrophilic layers at y = 0.

Anti-tumor necrosis factor-alpha antibody treatment reduces pulmonary inflammation and methacholine hyper-responsiveness in a murine asthma model induced by house dust

BACKGROUND/AIMS

Recent studies documented that sensitization and exposure to cockroach allergens significantly increase children's asthma morbidity as well as severity, especially among inner city children. TNF-alpha has been postulated to be a critical mediator directly contributing to the bronchopulmonary inflammation and airway hyper-responsiveness in asthma. This study investigated whether an anti-TNF-alpha antibody would inhibit pulmonary inflammation and methacholine (Mch) hyper-responsiveness in a mouse model of asthma induced by a house dust extract containing both endotoxin and cockroach allergens.

METHODS

A house dust sample was extracted with phosphate-buffered saline and then used for immunization and two additional pulmonary challenges of BALB/c mice. Mice were treated with an intravenous injection of anti-TNF-alpha antibody or control antibody 1 h before each pulmonary challenge.

RESULTS

In a kinetic study, TNF-alpha levels within the bronchoalveolar lavage (BAL) fluid increased quickly peaking at 2 h while BAL levels of IL-4, IL-5, and IL-13 peaked at later time-points. Mch hyper-responsiveness was measured 24 h after the last challenge, and mice were killed 24 h later. TNF inhibition resulted in an augmentation of these Th2 cytokines. However, the allergic pulmonary inflammation was significantly reduced by anti-TNF-alpha antibody treatment as demonstrated by a substantial reduction in the number of BAL eosinophils, lymphocytes, macrophages, and neutrophils compared with rat IgG-treated mice. Mch hyper-responsiveness was also significantly reduced in anti-TNF-alpha antibody-treated mice and the pulmonary histology was also significantly improved. Inhibition of TNF significantly reduced eotaxin levels within the lung, suggesting a potential mechanism for the beneficial effects. These data indicate that anti-TNF-alpha antibody can reduce the inflammation and pathophysiology of asthma in a murine model of asthma induced by a house dust extract.

Custom mega-prosthetic replacement for proximal humeral tumours

We used custom mega-prostheses in 57 patients with aggressive benign and malignant tumours of the proximal humerus. The most common tumour was osteosarcoma, followed by giant cell tumour and chondrosarcoma. We achieved extra-articular and wide resection margins in all primary malignant tumours and narrow margins in benign and metastatic tumours. Six patients died of disease, 4 patients developed local recurrences and 43 were continuously disease free at an average follow-up of 5.5 years (range 2-14.5 years). Five patients required revision replacements. The most common complications were proximal subluxation and aseptic loosening. Functional outcome was satisfactory in 78% of cases.

Dietzia strain X: a newly described Actinomycete isolated from confluent and reticulated papillomatosis

Confluent and reticulated papillomatosis (CRP) is a rare skin disorder. To date its aetiology remains uncertain. The possibility of an infectious aetiology has been supported by case reports of therapeutic response to antibiotic therapy. We have isolated and identified a previously unknown Dietzia strain, an Actinomycete, from skin scrapings of a 17-year-old boy with CRP. We propose that this organism may be the aetiological agent of CRP. Further investigations are necessary to determine the potential role of this Actinomycete in the pathogenesis of CRP.

A rare case of choroidal neovascularization following macular hole surgery

BACKGROUND

Choroidal neovascularization occurs in a wide spectrum of conditions, including degenerative, inflammatory, traumatic and hereditary conditions, all of which are characterized by breaks in Bruch's membrane. A few cases of choroidal neovascular membrane (CNVM) have been reported in the literature following macular hole surgery.

METHOD

We present a retrospective case study of a single patient who developed CNVM after successful macular hole surgery. The 70-year-old diabetic female underwent macular hole surgery in her right eye. Posterior hyaloid was separated with suction and vitrectomy was performed. Internal limiting membrane (ILM) was stained with trypan blue under air and ILM peeling was performed. Perfluoropropane (C3F8) gas was used as the tamponade. Six weeks post-operation, closure of macular hole was seen. Six months later, she presented with defective vision. Subfoveal classic CNVM was seen in the same eye.

DISCUSSION

About 1%-3% of patients who undergo macular hole surgery develop CNVM. Age-related changes and surgical trauma are considered to be the predisposing factors in reported cases. Injury to the retinal pigment epithelium (RPE) during surgery may be an important factor in our case, since there were no pre-existing age-related changes.

CONCLUSIONS

CNVM though rare can occur after macular hole surgery, especially in the setting of age-related changes. Injuries to the RPE should be avoided during surgery. We report a case of CNVM after macular hole in which trypan blue was used as a staining agent.