Isolation and characterization of mutants of Aspergillus niger deficient in extracellular proteases.

In the present study, the extracellular protease activity in a strain of the filamentous fungus Aspergillus niger was investigated and mutant strains deficient in the production of extracellular proteases were isolated. The major protease, which is responsible for 80-85% of the total activity, is aspergillopepsin A, a protein of ca. 43 kDa, the activity of which is inhibited by pepstatin.

The effect of endothelin 1 on the retinal microvascular pericyte.

The effect of the highly vasoactive peptide endothelin 1 (ET1) was tested on bovine retinal microvascular pericytes propagated in vitro. Specific binding of 125I-ET1 to retinal pericytes was documented by autoradiography. ET1 caused contraction of pericytes at a concentration of 0.

A study of D52S hen lysozyme-GlcNAc oligosaccharide complexes by NMR spectroscopy and electrospray mass spectrometry.

The production of a mutant hen lysozyme is described in which Asp-52, one of the catalytically important residues, is replaced by Ser. The mutant enzyme has very low catalytic activity but NMR studies show that its structure is closely similar to that of the wild-type protein. NMR experiments also show that well defined complexes are formed with GlcNAc4 and GlcNAc6 bound in the active site of the mutant enzyme.

Late presentation of congenital ectropion of the eyelids in a child with Down syndrome: a case report and review of the literature.

Congenital eversion or ectropion of the upper eyelids is rare. Only 50 cases have been reported since the condition was first described in 1896. We encountered an additional case of congenital ectropion of the eyelids, which is also unusual because of its late presentation for treatment.

Late ultrastructural changes in the retina of the rat following low-dose X-irradiation.

This study describes ultrastructural changes in the pigmented hooded Lister rat retina, 3-12 months following X-irradiation with single doses of between 200 and 2000 cGy. The extreme radiosensitivity of the photoreceptor cells was underlined by the continued manifestation of fine structural changes and cell death up to 6 months post-radiation in animals receiving doses above 500 cGy. The retinal pigment epithelial (RPE) cells were more radioresistant than photoreceptors and RPE cell loss was only observed at doses of more than 1500 cGy.

Congenital ichthyosis in a Libyan child with ophthalmic manifestations.

This report presents a Libyan child with congenital ichthyosis of the recessive lamellar variety complicated by severe ectropion of both upper and lower eyelids. Over a period of 12 months the degree of ectropion diminished and the anterior segments of the eyes were preserved using regular lubricating drops, vitamin A ointment and intermittent topical antibiotic therapy. Despite the pronounced initial upper eyelid ectropion no surgery was required to relieve the ectropion or prevent corneal exposure.

In vitro viability of choroidal melanomata following pre-enucleation irradiation.

In a group of eighteen patients with uveal melanomas, seven underwent low-dose pre-enucleation irradiation of approximately 2000 cGy. All the tumours were propagated in tissue culture and the growth characteristics of tumour cells from irradiated eyes were compared with tumour cells from non-irradiated eyes. Cultures were observed with phase-contrast microscopy, and radioactive thymidine labelling was used to study cell turnover.

Radiation retinopathy--clinical, histopathological, ultrastructural and experimental correlations.

Clinical, pathological and experimental studies of radiation retinopathy confirm that the primary vascular event is endothelial cell loss and capillary closure. Pericytes are less susceptible, but typically atrophy as the capillaries become non-functional. The immediate effects of radiation reflect interphase and early mitotic death of injured endothelial cells, whereas later changes may be attributed to delayed mitotic death of compromised endothelial cells as they attempt division in the ordinary course of repair and replacement.

Heterologous protein production by filamentous fungi.

There are clearly many facets to successful production of heterologous proteins from filamentous fungi. The objectives are to exploit the natural ability of some species to secrete high levels of protein. The heterologous target proteins produced in a fungal host must be acceptable to the public and be economic to produce, i.

The distribution of neuropeptides in the ocular tissues of several mammals: a comparative study.

1. The distribution of several neuropeptides (vasoactive intestinal peptide, substance P, somatostatin and neurotensin) was assessed in ocular tissues from the cow, sheep, rabbit and rat. 2.

Hen egg white lysozyme expressed in, and secreted from, Aspergillus niger is correctly processed and folded.

We transformed Aspergillus niger with the full length cDNA gene encoding hen egg-white lysozyme (HEWL) and its secretion signal sequence. Lysozyme levels up to 12 mg/l were secreted when expression was controlled by the A. awamori glucoamylase (GAM) promoter and 1 mg/l when controlled by the A.

Orbital infiltration by eyelid skin carcinoma.

This paper presents 5 patients seen in the Eye Clinic, Royal Victoria Hospital, Belfast with orbital infiltration of malignant eyelid tumours. The physical features and natural progression of the disease are described. The value of CT scans in determining the extent of the disease and patient management are described.

Cephalic radiation and retinal vasculopathy.

The retinal vascular complications in patients receiving cephalic radiation for various lesions over a ten year period were reviewed. The incidence of retinopathy was 17% overall, but increased with proximity of the treatment site to the eye, being highest in irradiation of the eye/orbit (85.7%), paranasal sinuses (45.

Fluorescein angiographic features, natural course and treatment of radiation retinopathy.

Fifteen patients who developed retinopathy following radiotherapy for cephalic tumours were studied by fluorescein angiography. Nine patients with unilateral or bilateral retinopathy had serial angiograms at six monthly or yearly intervals. Angiography revealed a wide range of retinal microvascular changes which were graded 1-4 according to the extent and degree of capillary malformation, incompetence and closure.

Autonomic function in Holmes Adie syndrome.

Autonomic function was studied in a group of 11 patients with Holmes Adie Syndrome. Autonomic function was assessed by the measurement of cardiovascular reflexes. Heart rate responses to respiration, valsalva manoeuvre and standing were studied.

DNA analysis and recombination in X-linked retinitis pigmentosa.

X-linked retinitis pigmentosa is a hereditary retinal degenerative disorder which has been localised to the proximal short arm of the X chromosome. Recent evidence suggests that the disorder is heterogeneous with two possible loci for the disease mutation. DNA analysis on the family presented in this paper showed that the mutation mapped to the more telomeric locus (RP3), thus enabling two flanking polymorphic DNA probes (XJ1.

Focal irradiation of perforating eye injuries.

Plaques constructed with 125I were used to irradiate the sites of perforating ocular injuries in rabbits. An approximate dose of 16Gy given over a period of 6 days was shown to significantly reduce intraocular cellular proliferation when irradiation was commenced within 24 hours after injury. If irradiation was delayed until day 5, this reduction in cellular proliferation and intraocular membrane formation did not occur.

Long-term glycaemic control and diabetic retinopathy.

216 patients with insulin-dependent diabetes mellitus were studied by retinal photography, and the absence or presence of retinopathy was related to the mean of serial glycosylated haemoglobin measurements (mean HbA1) carried out every 3 months during the previous 6 years. 122 patients had no diabetic retinopathy, 86 had background retinopathy, and 8 proliferative retinopathy. Mean HbA1 levels showed a strong correlation with increasingly severe grades of retinopathy, even when differences in duration of diabetes were taken into account.

A light microscopic and autoradiographic study of non-irradiated and irradiated ocular wounds.

Focal gamma irradiation was used to limit the intraocular extension of scar tissue which typically occurs after posterior perforating injury to the eye. Standard posterior perforating injuries were created in the right eye of forty-eight rabbits, half of which had the site of perforation focally irradiated using a Cobalt 60 ophthalmic plaque. Non-irradiated wounds healed with profuse formation of highly cellular and vascularised granulation tissue which invaded the vitreous to form contractile vitreo-retinal membranes.

Methanogenesis from ethanol by defined mixed continuous cultures.

Methanogenesis from ethanol by defined mixed continuous cultures was studied. Under sulfate-free conditions, a Desulfovibrio strain was used as the ethanol-degrading species producing acetic acid and hydrogen. In a two-membered mutualistic coculture, the hydrogen was converted to methane by a Methanobacterium sp.

On-line titration method for monitoring buffer capacity and total volatile fatty acid levels in anaerobic digesters.

The construction and use of an automatic on-line titration unit for routine or event- initiated monitoring of alkalinity, buffer capacity, and volatile fatty acid (VFA) levels is presented. Under computer control a sample of digester liquor is pumped into the titration vessel and weighed. A sequence of titration, sparging, and back-titration operations are then initiated during which the pH and weight are recorded continuously and a titration curve constructed.

Early ultrastructural changes after low-dose X-irradiation in the retina of the rat.

In this study Lister rats were given doses of X-rays ranging from 200-2,000 Rads to the retina of one eye, sacrificed at various time intervals between one hour and one month later and the irradiated eye processed for electron microscopy. The rod photoreceptor cells were by far the most radiosensitive cells in the retina, their outer segments showing distinctive membrane damage at one hour after 200 Rads of X-rays. Photoreceptor cell death was not seen at doses less than 1,000 Rads in the time period of the experiment.

Retinal ultrastructural findings in cone degeneration.

We studied an eye from a 73-year-old man with a sporadic type of retinal cone degeneration and choroidal melanoma. Histologic and ultrastructural studies of the nasal retina unaffected by the choroidal melanoma showed alterations at the outer retina predominantly involving the photoreceptors and retinal pigment epithelium. A wide spectrum of pathologic changes were observed, ranging from near normal retina showing only photoreceptor outer segment disease (distortion and kinking) to grossly pathologic regions where photoreceptor cell bodies were sparse and their outer segments absent.