Cloning and nucleotide sequence of Mycobacterium tuberculosis gyrA and gyrB genes and detection of quinolone resistance mutations

The emergence of multidrug-resistant strains of Mycobacterium tuberculosis has resulted in increased interest in the fluoroquinolones (FQs) as antituberculosis agents. To investigate the frequency and mechanisms of FQ resistance in M. tuberculosis, we cloned and sequenced the wild-type gyrA and gyrB genes, which encode the A and B subunits of the DNA gyrase, respectively; DNA gyrase is the main target of the FQs. On the basis of the sequence information, we performed DNA amplification for sequencing and single-strand conformation polymorphism analysis to examine the presumed quinolone resistance regions of gyrA and gyrB from reference strains (n = 4) and clinical isolates (n = 55). Mutations in codons of gyrA analogous to those described in other FQ-resistant bacteria were identified in all isolates (n = 14) for which the ciprofloxacin MIC was > 2 micrograms/ml. In addition, we selected ciprofloxacin-resistant mutants of Mycobacterium bovis BCG and M. tuberculosis Erdman and H37ra. Spontaneously resistant mutants developed at a frequency of 1 in 10(7) to 10(8) at ciprofloxacin concentrations of 2 micrograms/ml, but no primary resistant colonies were selected at higher ciprofloxacin concentrations. Replating of those first-step mutants selected for mutants with high levels of resistance which harbored gyrA mutations similar to those found among clinical FQ-resistant isolates. The gyrA and gyrB sequence information will facilitate analysis of the mechanisms of resistance to drugs which target the gyrase and the implementation of rapid strategies for the estimation of FQ susceptibility in clinical M. tuberculosis isolates.

Leukocyte adhesion molecules in rejected corneal allografts

Leukocyte adhesion molecules are believed to play a key role in the selective recruitment of different leukocyte populations to inflammatory sites. In this study, we investigated the presence and distribution of intercellular adhesion molecule-1 (ICAM-1), E-selectin (endothelial leukocyte adhesion molecule-1) and vascular cell adhesion molecule-1 (VCAM-1) in 12 rejected corneal allografts and compared the presence of these adhesion molecules with the composition of the associated inflammatory infiltrates. ICAM-1 was focally expressed on corneal epithelial cells and its expression was increased on keratocytes, corneal and vascular endothelial cells particularly at the site of dense infiltration with mononuclear leukocytes. E-selectin was present on endothelial cells of vessels in the stroma of rejected corneal allografts which were characterized by dense infiltration with T cells and macrophages. VCAM-1 was predominantly expressed on inflammatory cells of the macrophage/monocyte lineage, but only sporadically on vascular endothelial cells in the stroma of vascularized rejected corneal allografts. Our results suggest that ICAM-1, E-selectin and VCAM-1 may all be involved in the pathogenesis of corneal allograft rejection, particularly in the generation of the inflammatory infiltrates.

Leukocyte adhesion molecules in diseased corneas

PURPOSE

To help define the possible role of leukocyte adhesion molecules in the pathogenesis of corneal inflammation, we investigated the presence and distribution of intercellular adhesion molecule-1 (ICAM-1), E-selectin (endothelial leukocyte adhesion molecule-1 [ELAM-1]), and vascular cell adhesion molecule-1 (VCAM-1) in various corneal diseases.

METHODS

Monoclonal antibodies (mAbs) to ICAM-1, E-selectin, and VCAM-1 were used for immunohistochemical staining of frozen sections of 55 human corneas with various inflammatory and degenerative diseases. In addition, we used a panel of mAbs to characterize the composition and density of the inflammatory infiltrates in the diseased corneas.

RESULTS

ICAM-1 was focally expressed on epithelial cells in corneas with chronic allograft rejection, herpetic stromal keratitis, zoster keratitis, chemical burns, atopic keratitis, fungal keratitis, and bacterial keratitis. Furthermore, the expression of ICAM-1 was focally increased on keratocytes, corneal endothelial cells, and vascular endothelial cells (particularly at the site of lymphoid infiltration) in these corneas. E-selectin was present on vascular endothelial cells of limbal vessels in corneas with bacterial keratitis and also on endothelial cells of vessels in the stroma of several corneas with chronic inflammatory diseases. VCAM-1 was focally expressed on endothelial cells of vessels in the stroma of some corneas with chronic allograft rejection, herpetic stromal keratitis, chemical burns, and atopic keratitis. Interestingly, VCAM-1 was also found on inflammatory cells of the macrophage-monocyte lineage in inflamed corneas.

CONCLUSIONS

Our results demonstrate that ICAM-1, E-selectin, and VCAM-1 are expressed in diseased corneas, often in areas of inflammation.

Retinal phakomata associated with cerebral astrocytoma. An incomplete form of Bourneville-Pringle disease?

We report on a 21-year-old, male patient with unilateral retinal phakomata associated with histologically proved cerebral astrocytoma. The patient had presented with bilateral loss of vision and a left-sided hemiparesis. Ophthalmoscopy showed bilateral optic nerve atrophy, multiple punched-out areas of depigmentation and astrocytic hamartomata in the right eye. Despite the absence of classic signs of Bourneville-Pringle disease such as adenoma sebaceum, epilepsy and mental retardation, a strongly presumptive diagnosis of tuberous sclerosis could be made. This unusual case demonstrates that retinal phakomata can be the solely visible manifestation of Bourneville-Pringle disease.

[Leukocyte adhesion molecules in chronic inflammatory diseases of the cornea]

Using immunohistochemical techniques, we investigated the expression of leukocyte adhesion molecules-intercellular adhesion molecule-1 (ICAM-1), E-selectin (endothelial leukocyte adhesion molecule-1), and vascular cell adhesion molecule-1 (VCAM-1)--in various chronic inflammatory corneal diseases of different etiology. ICAM-1 was focally expressed on epithelial cells and showed an increased expression, on keratocytes, corneal endothelial cells, and vascular endothelial cells. E-selectin was present on vascular endothelial cells of several corneas, while VCAM-1 was found particularly on macrophages and only sporadically on vascular endothelial cells. Our results suggest that ICAM-1, E-selectin, and VCAM-1 may be involved in the pathogenesis of various chronic inflammatory corneal diseases, particularly in the selective recruitment of different leukocyte populations.

Effects of bright artificial light on monoamines and neuropeptides in eight different brain regions compared in a pigmented and nonpigmented rat strain

Seasonal affective disorder is a form of depression which recurs at the same time of the year. Exposure to bright artificial light at a dose of 2,500 lux is used to treat seasonal affective disorders. We exposed a pigmented (Brown Norway) and a nonpigmented (Sprague-Dawley) rat strain with bright artificial light for 21 days at two doses (2,500 and 6,100 lux) and analyzed dopamine, dihydroxyphenyl-acetic acid, 5-hydroxytryptamine (5-HT), and 5-hydroxyindole-acetic acid (5-HIAA) by high performance liquid chromatography (HPLC) and electrochemical detection in eight different brain regions. Furthermore, we measured tissue levels of substance P (SP), neurokinins (NK), vasoactive intestinal polypeptide (VIP), calcitonin gene-related peptide (CGRP), and neuropeptide Y (NPY) with radioimmunoassay. Our data obtained with light microscopy show that bright artificial light at both doses induced a massive destruction of photoreceptors in the retina of albino rats but not of the pigmented rat strain. Retinal lesion of photoreceptors resulted in increased tissue levels of all measured neuropeptides except SP in the hypothalamus and increased VIP in the ventral tegmental area/substantia nigra. Furthermore, increased 5-HT and 5-HIAA tissue levels were found in the ventral tegmental area/substantia nigra. In contrast, in the frontal cortex there was a significant reduction in 5-HIAA tissue levels and a decreased 5-HIAA/5-HT ratio, indicating decreased 5-HT metabolism. Light exposure of the pigmented rat strain revealed no changes in the measured biogenic amines and neuropeptides in any investigated brain region. Our data suggest that retinal lesion but not direct visual neurotransmission induced changes in neurotransmitters in some brain regions. We conclude that Brown Norway rats but not Sprague-Dawley rats are useful to study neurochemical effects of bright artificial light. However, Sprague-Dawley rats may be a useful tool to study biochemical mechanisms of photoreceptor damage by bright light.

Altered lectin binding sites in keratoconus corneas

We investigated the glycoconjugates in frozen sections of keratoconus corneas, using a panel of 12 biotin- or fluorescein isothiocyanate-labeled lectins. No differences between the lectin binding sites of the epithelium, endothelium and Descemet's membrane of normal and keratoconus corneas could be observed. However, in contrast to normal corneas, intense staining with peanut agglutinin (PNA) could be detected at breaks in Bowman's layer, in scar tissue and in the adjacent stroma. Furthermore, in the majority of cases binding sites for Phaseolus vulgaris erythroagglutinin (PHA-E) and increased staining with Ricinus communis agglutinin I (RCA-I) and Lens culinaris agglutinin (LCA) could also be detected in ruptures in Bowman's layer and in scar tissue. These data suggest that the scarred regions of the anterior stroma in keratoconus corneas may contain oligosaccharides with terminal D-galactose (beta 1-3)-D-N-acetylgalactosamine disaccharides (recognized by PNA), increased amounts of glycoconjugates with terminal beta-galactose residues (recognized by RCA-I), increased amounts of glycoconjugates with glucose/mannose residues (recognized by LCA), and finally, biantennary complex-type glycopeptides containing two outer galactose residues and a residue of N-acetylglucosamine (recognized by PHA-E). Since corneal scars due to causes other than keratoconus revealed lectin binding sites (particularly for PNA and to a lesser extent also for PHA-E, LCA and RCA-I) similar to those seen in scar tissue of keratoconus corneas, we conclude that it is mainly scar formation that may be responsible for the altered lectin binding sites in keratoconus.

[Newer information about several aspects of animal epidemic disinfection]

The amendment of the German Veterinary Legislation concerning the eradication of notifiable diseases demanded also an updating of the relevant disinfection measures and technologies. Some hints are given, based on own experimental results, for the choice of chemical disinfectants, on some special problems of disinfection in livestock buildings and of disinfection of animal slurry and farm-yard manure as well as on biotechnological disinfection methods and environment-friendly disinfectants.

Orbital involvement in Waldenström's macroglobulinemia: ultrasound, computed tomography and magnetic resonance findings

A case of orbital involvement in Waldenström's macroglobulinemia is presented. Orbital echography, computed tomography (CT) and magnetic resonance imaging (MRI) were performed and revealed a retrobulbar mass of the right orbit. Ultrasonography suggested a lymphoid orbital tumor. A CT scan was nonspecific, but helpful in exactly locating the tumor and excluding bony lesions. Signal intensity patterns of MRI were characterized by a low intensity on T1- and T2-weighted images. A marked enhancement of the tumor was evident after intravenous injection of a paramagnetic contrast agent (gadolinium-DTPA). Although the definite diagnosis could only be established by means of an ultrasound-guided fine-needle aspiration biopsy, MRI in connection with the history of our patient strongly suggested a diagnosis of orbital lymphoma in Waldenström's disease.

Human papillomavirus type 42: new sequences, conserved genome organization

We report the nucleotide sequence and genome organization of the human papillomavirus type 42. HPV42 DNA was isolated from vulvar papillomas. It has been detected in benign forms of proliferative lesions only. The genome of HPV42 is 7917 bp long and shows the open reading frame pattern conserved in all HPVs sequenced so far. HPV42 has no high degree of sequence homology to any of the known HPVs. It shows characteristics previously found either exclusively in HPVs associated with invasive carcinomas or exclusively in nongenital HPVs. Therefore it cannot be readily ascribed to any of the established subgroups of human papillomaviruses.

T6-positive Langerhans cells in diseased corneas

Langerhans cells (LC) in normal human corneas (with the exception of newborns) lack thymocyte antigen T6, a highly specific marker for noncorneal LC. Because corneal LC could not be induced to express T6 antigen when cultured with various cytokines including interleukin-1 (shown to modulate T6 expression on gingival LC), some authors assume that corneal LC may represent a distinct LC subpopulation that is innately inactive. In this study, 62 corneas from patients with various corneal diseases were investigated for the presence of T6 and histocompatibility antigen HLA-DR on LC in the central and pericentral epithelium. Both T6- and HLA-DR-positive LC at a high density similar to that observed in normal epidermis could be detected in the epithelium of five corneas with epidermalization after alkali burns. Furthermore T6- and HLA-DR-positive LC at smaller densities also were detected in corneas from patients with chronic herpetic stromal keratitis, zoster keratitis, chronic allograft rejection, and bacterial corneal ulcers. Although the functional significance of T6 expression on corneal LC remains to be determined, the induction of T6 antigen on corneal LC may represent an important event for the antigen-presenting function of these cells in various corneal diseases including corneal allograft rejection.

Determination of the monoamine oxidase B inhibitor Ro 19-6327 in plasma by high-performance liquid chromatography using precolumn derivatization with fluorescamine and fluorescence detection

A specific high-performance liquid chromatographic (HPLC) method using precolumn derivatization and fluorescence detection was developed for the determination of the monoamine oxidase B inhibitor Ro 19-6327 in human plasma. After extraction of the basified plasma with tert.-butyl methyl ether-1-butanol (8:2, v/v) and back-extraction into dilute phosphoric acid, the solution was neutralized with phosphate buffer and the drug derivatized with fluorescamine. The derivative was chromatographed on a reversed-phase C8 column, using phosphate buffer-acetonitrile (68:32, v/v) as mobile phase, and fluorescence detection (excitation 370 nm, emission 485 nm). The limit of quantification was 1 ng/ml using 1 ml of plasma. The recovery was 79% in the range 5-200 ng/ml and the inter-assay precision was 3.1-7.9% in the range 2-500 ng/ml. The compound proved to be stable in human plasma. Moderate instability was found in rat plasma and, surprisingly, severe instability in dog plasma. Measures for handling unstable dog plasma samples are described. An HPLC method with UV detection was used for the analysis of dog and rat plasma samples, which is also described briefly. The fluorescence method, which was five times more sensitive than the UV method, was successfully applied to a human tolerance study.

Clinicopathological findings 11 months after implantation of a functioning aqueous-drainage silicone implant

An aqueous-drainage silicone device was implanted in a 57-year-old diabetic patient with neovascular glaucoma after failure of conventional therapy. Postoperative intraocular pressure (IOP) was well controlled, ranging between 10 and 20 mm Hg without the use of supplemental agents. Despite the normal IOP, the eye became painful and amaurotic 11 months after implantation due to progression of the retinopathy accompanied by the development of severe tractional retinal detachment. Enucleation was performed and the eye underwent histopathological examination. The filtering bleb around the silicone plate of the implant on the equatorial sclera was lined with a thick layer of collagenous connective tissue. Numerous microcystic spaces could be seen in the bleb wall by light microscopy. Electron microscopy confirmed this finding; in addition, only a meshwork of collagen fibre-like bundles was visible at some areas of the innermost bleb wall. Control of IOP in spite of bleb fibrosis in this particular case may have been due to a loss of matrix components and to the formation of microcystic spaces in the bleb wall, which seem likely to be channels for the passage of aqueous humor.

Toxicity and clearance of intravitreal cefotetan

Direct intravitreal injection of antibiotics plays an important role in the management of bacterial endophthalmitis. In the present study we investigated the toxicity and clearance of intravitreally injected cefotetan in a rabbit model. No toxic ocular side effects could be detected by electroretinography (ERG) or light and electron microscopy up to and including a single intravitreal dose of 1000 micrograms. Intravitreal injection of 2000 micrograms cefotetan resulted in mild degeneration of photoreceptor outer segments and, sporadically, in cataract formation. After intravitreal injection of 4000 micrograms, moderate toxic degeneration of photoreceptors occurred, with displacement and mitochondrial swelling of inner segments. In addition, lysosomal lamellar inclusion bodies could be detected in pigment epithelial cells. After a single intravitreal injection of 1000 micrograms cefotetan, concentrations greater than the minimum necessary for the inhibition of most commonly occurring intraocular pathogens (except Pseudomonas aeruginosa and Staphylococcus epidermidis) were maintained in the vitreous humor for greater than 48 h. Cefotetan may be a potentially important drug for intravitreal injection, especially in cases of gram-negative and suspected anaerobic endophthalmitis.

Investigation of visual field defects in strabismic and anisometropic amblyopes with the Octopus program G1

Using the Octopus G1 program, we investigated the visual fields of amblyopic and healthy contralateral eyes in 21 patients with strabismic amblyopia and 14 patients with anisometropic amblyopia. All subjects had a visual acuity of 0.7-0.06. A central scotoma was detected in 85.7% of the patients with strabismic amblyopia and in 79% of those with anisometropic amblyopia. The mean maximal depth of central scotomas in subjects with strabismic amblyopia was 6.81 +/- 4.74 dB (mean +/- SD); in those with anisometropic amblyopia, it was 6.64 +/- 4.34 dB. This difference was statistically not significant. However, in patients with anisometropic amblyopia, the visual field indices MD (mean defect) and CLV (corrected loss variation) were significantly higher than in those with strabismic amblyopia (P less than 0.05 vs P less than 0.05); this was predominantly due to additional flat defects that occurred paracentrally and peripherally in subjects with anisometropic amblyopia. In both groups of patients, we found a significant negative correlation between visual acuity, on the one hand, and the maximal depth of the scotomas and the visual field indices (MD and CLV), on the other.

Corneal carcinoma

Carcinomas of the cornea have not yet been described in the literature. A 50-year-old man underwent keratoplasty because of corneal dystrophy. Microscopic examination disclosed a squamous-cell carcinoma which had spread over the entire cornea and just reached the limbus.

Late manifestation of conjunctival malignant melanoma

The patient, who is now 60, had a nevus and areas of cystic changes in the conjunctiva in her right eye, which had been present from birth to the age of 59. In 1987, rapid tumor growth aroused suspicion that malignant change could be occurring and so the nevus as well as the area of the conjunctiva containing cystic changes were excised. Histological finding: conjunctival malignant melanoma, containing compressed (densely arranged) atypical cells with pleomorphic hyperchromatic nuclei and prominent nucleoli. The biopsy specimen of the conjunctiva showed a typical nevocellular nevus with large inclusion cysts of the conjunctival epithelium.

[Spontaneous corneal rupture after strontium irradiation of a conjunctival squamous cell carcinoma]

A 87-year-old female patient with a squamous cell carcinoma of the conjunctiva was treated with local strontium-90 irradiation (with a so-called 'Dermaplatte'). In spite of a relatively low dosage, radiotherapy was followed by a corneal ulcer with consecutive rupture of the cornea. The cause of this unexpected perforation was, besides the effect of low-dose irradiation, probably a metabolic disorder of the cornea and a disturbance of the tear film due to the carcinoma which had spread on Bowman's layer of the cornea in an exophytic manner and was accompanied by a dense lymphocytic infiltration. An exenteration was performed and, at the last examination (1 year later), no local recurrence could be detected.

[Analysis of a dacrolith ]

Dacryoliths are uncommon and there are only a few reports in the literature. In a patient with recurrent stenosis of the lacrimal drainage system a lacrimal stone (dacryolith) was removed from the lacrimal sac during dacryocystorhinostomy. A histological and immunohistochemical examination was performed and keratin antibodies could be detected. In a chemical analysis calcium, sulfur and some phosphorus were determined as major constituents.

[Studies of the penetrating ability of fosfomycin into the aqueous humor and vitreous body of the eye]

Fosfomycin is an antibiotic with a new simple chemical structure and a broad spectrum of antibacterial activity, especially against staphylococci. In the study reported here, the penetration of fosfomycin into the aqueous humor and vitreous body was investigated after intravenous infusion of 4 and 8 g. The highest average concentration approximately 2 hours after administration was 28.3 micrograms/ml after the 4 g dose and 52 micrograms/ml after the 8 g dose. Both the 4 g and 8 g doses thus produced aqueous humor levels exceeding the minimum inhibitory concentrations required for most gram-positive and gram-negative organisms commonly responsible for bacterial endophthalmitis, including strains of pseudomonas aeruginosa. Extremely high aqueous humor levels of fosfomycin were observed in two patients with inflamed eyes because of a change in the blood-aqueous barrier.

[Carotinoid deposits in the retina]

In this case report a 55-year-old Turkish patient with polymorphous light eruption, who has been treated with high doses of beta-carotene and canthaxanthin for more than 6 years is described. The examination of the fundus showed dense, glistening bright yellow crystalline deposits around the maculae. The only functional impairment that could be detected was a slight decrease in visual acuity and dark adaptation.