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Biomedical subjects

L D Ormerod

Publications and source records attributed to L D Ormerod.

At least 55 records · Page 3Linked to original sources
PubMed1988

Idiopathic bilateral lipid keratopathy.

A 52-year-old Mexican man presented with asymptomatic, bilaterally symmetrical lipid infiltrates of the cornea and adjacent limbus. No evidence of previous ocular disease or systemic disorder of lipid metabolism could be detected. Penetrating keratoplasty of the right eye was required. The cornea was rigid and thick, with posterior bulging into the anterior chamber. Light microscopy revealed deep corneal lipid granules, foamy histiocytes, vascularisation, and chronic non-granulomatous inflammation. Transmission electron microscopy showed extracellular lipid spaces and numerous intracytoplasmic lipid vacuoles in histiocytes, keratocytes, conjunctival epithelium, and the endothelium of blood vessels in the corneal stroma and adjacent limbal conjunctiva. Histochemical analysis revealed the presence of neutral fats, free fatty acids, cholesterol, and phospholipids.

Cholesterol↗
PubMed1988

Ocular Capnocytophaga infection in an edentulous, immunocompetent host.

Severe microbial keratitis developed in a 74-year-old women receiving long-term corticosteroids. Corneal smears revealed slender, fusiform gram-negative bacilli, but the lesion continued to worsen despite intensive antibiotic treatment. After several days, Capnocytophaga sputigena was identified on culture. Specific antimicrobial therapy was instituted, supplemented with corneal cryotherapy. There was gradual clinical improvement. However, a sterile corneal melt led to the late loss of the eye. Although Capnocytophaga are gingival organisms and usually implicated as opportunists in severely ill, neutropenic patients with oral ulcerations, our patient was edentulous and without systemic immunosuppression. An increased awareness of Capnocytophaga is justified because of their widespread antibiotic resistance, capnophilic cultural requirements, and unusual microscopic and cultural morphology.

Aged↗
PubMed1988

Lymphoid immunohistochemistry of macaque primates.

The immunohistochemical localizations of 53 monoclonal antibodies with specificities expressed in human lymphoid tissue were investigated on lymph node tissues from Macaca mulatta, M. speciosa, and M. fascicularis using immunoperoxidase techniques. Thirty antibodies showed comparative cross-reactivity. The micro-anatomic distribution of these antigens was closely homologous to that observed in man and antigen densities appeared to be similar. A useful monoclonal antibody panel for immunopathological investigations in macaques was, thereby, defined. Of several pan-T antibodies studied, only OKT11(CD2) showed cross-reactivity. A detailed analysis of the immunocyto-architecture of five rhesus lymph nodes was undertaken. Automated flow cytometry of M. mulatta and M. speciosa peripheral blood showed a broadly similar pattern to man.

Animals↗
PubMed1987

Pseudomonas corneoscleritis.

We evaluated three cases of Pseudomonas aeruginosa corneoscleritis, one associated with the use of contaminated eyedrops; another in an elderly, debilitated patient; and the third in a patient who had previously undergone penetrating keratoplasty. In the first two cases, control of the infection was achieved by intensive antibiotic therapy alone. The third case required evisceration of the eye following spontaneous perforation at the site of scleral involvement. Histopathologic findings showed persistence of the organism in the sclera despite intensive antibiotic therapy for six days.

Aged↗
PubMed1987

The intraocular environment and experimental anaerobic bacterial endophthalmitis.

Anaerobic bacteria are prevalent in conjunctival flora but have not been adequately investigated as possible causes of endophthalmitis. The mean oxidation-reduction potential (Eh) of the rabbit vitreous was found to be +25.1 mV, well within the limiting Eh value of many anaerobes. There was an oxygen pressure gradient in the vitreous ranging from 2.1 mm Hg immediately posterior to the lens to approximately 20 mm Hg adjacent to the medullary ray. Endophthalmitis was produced with pure cultures of Fusobacterium necrophorum, Propionibacterium acnes, and Peptostreptococcus magnus. Relatively small inoculates of F necrophorum caused severe, acute endophthalmitis with scleral perforation; P acnes and P magnus produced a self-limited endophthalmitis; and vitreoretinal fibrosis was a sequela of the Propionibacterium acnes infection.

Animals↗
PubMed1987

Causation and management of microbial keratitis in subtropical Africa.

Microbial keratitis is a major cause of corneal blindness in developing countries. One hundred thirty-one episodes of corneal infection in 120 patients over an 11-month period from Soweto, South Africa, were reviewed. Severe staphylococcal lid disease, trauma, and the secondary infection of climatic droplet keratopathy were the major precedents. Unilateral mixed patterns of infection, bilateral keratitis, and childhood keratitis were common. Staphylococci, streptococci, or gram-negative enteric bacilli were the usual causative organisms. Admission rates of corneal perforation were high. Small perforations often could be managed medically without tissue glue. In developing countries, logistic problems necessitate subconjunctival antibiotic therapy; the nursing staff may be too overextended to satisfactorily maintain topical antibiotic regimens. Effective, inexpensive antibiotic dosing schedules, which are appropriate for use by the general medical officer and ancillary health worker, must be developed.

Adolescent↗
PubMed1987

Ophthalmic manifestations of maxillary sinus mucoceles.

Mucoceles involving any of the paranasal sinuses may present with ophthalmic disturbances. Maxillary antral mucoceles can encroach on the inferior orbit with ocular displacement and compression, proptosis or enophthalmos, lower lid distortion, tethering of extraocular muscles, and ptosis. Periocular pain, erosion of the inferior orbital rim, infraorbital nerve compression, epiphora, and inner canthal swellings are other important presentations. Postoperative mucoceles may involve only a portion of the antrum. Five illustrative cases are presented.

Adult↗
PubMed1987

Anaerobic bacterial endophthalmitis.

Eighteen patients with endophthalmitis involving anaerobic bacteria are presented. Endophthalmitis followed cataract surgery in seven patients, penetrating trauma in six, a corneal graft in two, and an infected filtering bleb in two; there was one case of endogenous endophthalmitis. Propionibacterium acnes was the most frequent anaerobe isolated (78% of cases). Thirty-two percent of the patients had polymicrobial infection with mixed aerobic and anaerobic species. Six cases of acute P. acnes endophthalmitis were clinically indistinguishable from other cases of mild to moderately severe endophthalmitis. Four patients presented, after cataract surgery, with chronic, low-grade endophthalmitis of 1 to 15 months' duration, emphasizing that "sterile" endophthalmitis cannot be satisfactory diagnosed clinically. The visual prognosis of treated P. acnes endophthalmitis was often good. Based on principles of anaerobic microbiology, recommendations are made for vitreous collection, transport, and culture.

Adolescent↗
PubMed1987

Epidemiology of microbial keratitis in southern California. A multivariate analysis.

Two hundred twenty-seven cases of microbial keratitis reported in nonreferral county practice were studied. The staphylococci, Pseudomonas aeruginosa and Streptococcus pneumoniae, were the major isolates. A multivariate statistical model was developed to evaluate possible predisposing and outcome determinants. Several racial and age-related relationships were shown. The interaction of numerous local ocular and systemic factors played a fundamental role in causing disease. The authors found significant association between S. pneumoniae and topical steroid use, and direct and indirect linkage of S. aureus with diabetes and trauma, respectively. S. pneumoniae and Moraxella were risk factors for major complications (24% of cases); S. pneumoniae was related to enucleation and late perforation. Corneal exposure and prior topical steroids were associated with prolonged hospital stays. Hypopyon was associated with pneumococcal infection, 60 years of age or older, and trauma. The identification of groups at high-risk for microbial keratitis and problems of preventive management are discussed.

Bacterial Infections↗
PubMed1987

Spontaneous hyphaema and corneal haemorrhage as complications of microbial keratitis.

Hyphaema developed spontaneously in 16 of 458 patients with microbial keratitis treated at two centres on the East and West Coasts of the United States. Chronic corneal conditions were often present, and three cases had rubeosis iridis. Inflamed iris vessels were assumed to be the source of the haemorrhage. The hyphaemas tended to persist longer than is usual, particularly when coincident with a hypopyon. Recurrent hyphaemas are reported in two patients from outside this series. Spontaneous corneal haemorrhage was seen in three cases. Subepithelial bleeding settled rapidly, but a combined midstromal and pre-Descemet's haematoma cleared more slowly. Anterior segment bleeding was significantly associated with advanced age, female sex, infection with Gram-positive organisms, and hypopyon.

Adult↗
PubMed1987

Immunopathology of acute experimental histoplasmic choroiditis in the primate.

The immunopathologic features of experimental acute histoplasmic choroiditis were studied in the nonhuman primate. Using an indirect immunoperoxidase technique, a panel of hybridoma-derived anti-human monoclonal antibodies, recognizing distinct lymphoid cell and macrophage surface antigens, have been adapted for use in the primate system. Twenty-two individual foci of histoplasmic choroiditis from five eyes were studied at time periods from 20 to 60 days post intracarotid injection of yeast phase Histoplasma capsulatum. A mononuclear and granulocytic cell infiltration was seen in all lesions. The predominant cell type was the CAPPEL+ T lymphocyte (suppressor/cytotoxic subset). Other cell types found in smaller numbers were OKT4+ T cells (helper/inducer subset), OK7+ (peripheral B lymphocytes), IgD+ (mantle B cells) and OKM1+ cells (macrophages and polymorphonuclear leukocytes). Herein, we present immunopathologic data on the acute phase of experimental ocular histoplasmosis.

Acute Disease↗
PubMed1986

Contact lens-associated microbial keratitis.

During a 14-year period, 42 cases of microbial keratitis were associated with contact lens (CL) wear. Pseudomonas aeruginosa was isolated in 40% of the cases and Staphylococcus in 31%; Streptococcus pneumoniae, alpha-hemolytic Streptococcus, and Serratia marcescens were the next most commonly isolated pathogens. There was a single fungal corneal ulcer. Bandage CL use was associated with a high prevalence of infection with quasi-commensal organisms and with polymicrobial keratitis, a pattern of disease quite distinct from that induced by other types of CLs. Marked visual loss frequently occurred. There was a disturbing increase in the number of infections associated with extended-wear CLs (worn for either aphakia or myopia) over the last 18 months of the study.

Adolescent↗
PubMed1986

Immunological concepts and the eye: a review of the classical and ocular arthus reactions.

Inflammatory processes can involve any tissue in the eye. Despite advances in therapy, the sequelae of inflammation continue to be a major cause of visual impairment. Knowledge of disease pathogenesis in clinical ocular inflammations remains imprecise, and defined models are crucial in developing this understanding and evolving rational approaches to treatment. This review analyzes the contributions that studies of the classical and Arthus ocular Arthus-type reactions have made as to how the eye functions as an immunological entity. The anticipated development of therapeutic agents that may modulate immune processes with remarkable specificity, gives a new impetus to such experimental studies.

Animals↗
PubMed1986

Microbial keratitis in children.

Forty-seven eyes with microbial keratitis occurring in 44 children under 16 years of age were studied. Under the age of three, 92% of the infections involved Pseudomonas aeruginosa and/or various streptococcal species; later in childhood the typical adult pattern of infection was more common. Overwhelming systemic infections, malignant disease with orbital involvement and congenital ocular adnexal disease were important predisposing factors in the infant years; trauma and acquired external eye disease became increasingly important in mid-childhood. Surgery was necessary in 28% of the eyes. Frequent tearing and lack of patient cooperation preclude reliance on topical antibiotic therapy alone. Despite the difficulties, the mainstay of management involves daily biomicroscopic evaluation and regular subconjunctival antibiotic injections. The logistical problems of achieving these aims are discussed.

Age Factors↗
PubMed1986

In situ characterization of T lymphocyte subpopulations in leprosy in the mangabey monkey.

Leprosy in the mangabey monkey is an experimental model which is similar both clinically and histologically to human lepromatous leprosy. The immunopathology of these diseases was compared using monoclonal antibodies against T lymphocyte subpopulations in frozen tissue sections with an immunoperoxidase technique. In both mangabey and human lepromatous granulomas OKT4 (or Leu 3a) and Leu 2a cells were scattered among macrophages with greater numbers of Leu 2a as compared with OKT4 (or Leu 3a) cells. The results suggest that from an immunopathological standpoint experimental leprosy in mangabeys will provide a suitable model for the investigation of the pathogenesis of human lepromatous leprosy and for the evaluation of new antileprosy vaccines.

Animals↗
PubMed1977

Poisoning by bites of the saw-scaled or carpet viper (Echis carinatus) in Nigeria.

The Saw-scaled or Carpet Viper (Echis carinatus) whose range extends from Senegal to Bengal probably bites and kills more people than any other species of snake. One hundred and fifteen patients with poisoning caused by its bite were studied in the savanna region of Nigeria, where victims of this snake may occupy 10 per cent of hospital beds. Patients showing no signs of envenoming were excluded. All patients had local swelling at the site of the bite. Other features included local blistering (13 per cent), local necrosis (11 per cent), incoagulable blood (93 per cent), and spontaneous systemic bleeding (57 per cent). There was evidence of disseminated intravascular coagulation in all cases; fibrinogen was severely depleted, fibrin degradation products were increased (mean 1711 +/- 904 micron per ml), but significant thrombocytopenia (less than 103 000 per mm3) was seen in only ten severe cases. Clotting factors V, VIII, II and XIII were depleted, while X and VII were usually normal. Fibrinolytic activity was rarely increased, so it seems likely that a procoagulant action (direct activation of prothrombin) is principal effect of E. carinatus venom on blood coagulation in man. Development of the haemostatic defect was observed as early as 75 minutes and as late as 27 hours after the bite. Spontaneous haemorrhage is clinically the most important effect of E. carinatus venom, causing the five deaths in this series. The relative importance of procoagulant and haemorrhagic components of the venom in causing haemorrhage is discussed. Complement activation via the classical and alternative pathways may have contributed to vascular damage. Mortality was reduced from the untreated level of between 10 and 20 per cent to 2.8 per cent in a group of 107 patients treated with 10 to 110 ml of specific antivenom. The dose was controlled using a simple clotting test. Blood coagulability was restored in two to 39 (mean 12) hours after the first dose of antivenom. Immediate-type serum reactions were observed in 21 per cent of cases. Additional treatment included blood transfusion for patients in haemorrhagic shock and ealry surgical débridement of necrotic tissue at the site of the bite.

Adolescent↗