Search PubMed⌕ Search

Biomedical subjects

H Lewis

Publications and source records attributed to H Lewis.

At least 109 records · Page 6Linked to original sources
PubMed1989

Subretinal membranes in proliferative vitreoretinopathy.

Subretinal membranes (SRMs) are an important but rarely identified component of proliferative vitreoretinopathy (PRV). In 153 consecutive cases that had vitreoretinal surgery for this condition and were followed for at least 6 months, SRMs were encountered in 72 eyes (47%). In 20 (28%) of the 72 eyes, the SRMs prevented complete retinal reattachment and needed to be removed or excised through one or multiple retinotomies. Intraoperative complications related to the SRMs or their removal included choroidal or retinal hemorrhage in three eyes (15%), subretinal air in three eyes (15%), and unplanned extension of the retinotomies in two eyes (10%). The 20 eyes requiring SRMs removal were followed for a median of 11 months. Retinas were reattached in 13 eyes (65%), although only 4 eyes (20%) had a visual acuity of 5/200 or better. Recognizing SRMs as a component of PVR is important in helping to maximize the anatomic success rate although the effects on visual function are not fully known.

Adult↗
PubMed1989

Mechanisms of intraocular pressure elevation after pars plana vitrectomy.

A prospective study of 222 consecutive patients undergoing pars plana vitrectomy was done to determine the incidence and mechanisms of postoperative intraocular pressure (IOP) elevation. Within 48 hours of surgery, postoperative IOP increased by at least 5 to 22 mmHg in 136 eyes (61.3%) and to 30 mmHg or more in 79 eyes (35.6%). Presumed mechanisms of open-angle glaucoma included intraocular gas expansion (28.4%), inflammatory trabecular meshwork obstruction (4.5%), silicone oil-related glaucoma (3.6%), and erythroclastic glaucoma (2.2%). Closed-angle mechanisms included pupillary block glaucoma (6.8%) and ciliary body edema (3.6%). Factors which were associated with postvitrectomy pressure elevation included placement of a scleral buckle, either intraoperatively (P = 0.003) or before vitrectomy (P = 0.001), intraoperative scatter endophotocoagulation (P = 0.041), intra-operative lensectomy (P = 0.024), and development of postoperative fibrin membranes (P = 0.038). Surgery was required to lower IOP or relieve pupillary block in 25 eyes (11.3%).

Adolescent↗
PubMed1989

Complications of endodrainage retinotomies created during vitreous surgery for complicated retinal detachment.

The authors report nine cases of endodrainage retinotomy site complications that occurred after vitreous surgery for complicated retinal detachments (RDs). Postoperative subretinal neovascularization developed in four eyes at the retinotomy drainage site. In two eyes, postoperative proliferation at a posteriorly placed endodrainage site created traction macular detachments. Redetachment due to retinotomy opening caused by postoperative drainage site proliferation developed in three eyes. The retinas of all nine eyes were eventually reattached, and vision improved from the preoperative level. These complications are related to retinal pigment epithelium and/or Bruch's membrane damage during internal subretinal fluid drainage and retinotomy endolaser photocoagulation. Careful evaluation of extrusion instruments, drainage techniques, retinotomy placement, and subsequent endolaser treatment is necessary to minimize these complications.

Adolescent↗
PubMed1989

An effective day treatment model for young children with pervasive developmental disorders.

A day treatment program was provided for 31 children (ages 2 through 6) with DSM-III diagnoses of infantile autism or pervasive developmental disorder. The main intervention strategies were use of positively charged affective experiences to aid the development of close interpersonal relationships, use of play in all its interpersonal, cognitive, and structural variety, and a pragmatics-based language therapy model delivered within a highly predictable and carefully structured milieu. Over a 6-month intervention period, subjects demonstrated significant treatment effects in cognition, perceptual/fine motor, social/emotional, and language skills, which were maintained or increased over a 12- to 18-month treatment period. Play skills increased significantly in symbolic complexity, symbolic agency, and symbolic substitutions. Additionally, there was significant reduction of autistic symptomology.

Affect↗
PubMed1989

Clinicopathologic findings in a patient with serpiginous choroiditis and treated choroidal neovascularization.

We present the ocular clinicopathologic features of the left eye of a patient who, during a 29-year period, developed the characteristic features of progressive serpiginous choroiditis. Two areas of choroidal neovascularization were successfully treated by laser photocoagulation. The larger area of neovascularization, located in and inferior to the maculopapillary bundle area and treated with argon laser, resulted in a scar composed of hyperplastic retinal pigment with persistence of neovascularization and full-thickness destruction of the retina. A smaller area of neovascularization, located temporal to the fovea and treated by krypton laser, resulted in a fibrous scar with obliteration of the new vessels and preservation of the inner retinal layers. A diffuse and focal infiltrate of lymphocytes was present in the choroid. Often, larger aggregates of lymphocytes were present at the margin of the serpiginous lesions. The serpiginous lesions were characterized by loss of retinal pigment epithelium and the photoreceptor cell layer. The margins of most lesions had variable degrees of hyperplastic retinal pigment epithelium and some had defects in Bruch's membrane, through which fibroglial scar tissue extended into the choroid.

Choroid↗
PubMed1989

Electron microscopic study of the unique features and structural-morphologic relationship of canine bone marrow.

Electron microscopy revealed several unique features in canine bone marrow, compared with that of other species. The marrow was fatty and extensively trabeculated and was enclosed by a complete layer of endosteal bone-lining cells. Branched reticular cells were closely associated with each other and, occasionally, covered part of the sinus wall as an adventitial layer. The extent of adventitial coverage varied markedly and was less extensive, compared with that of other species. On average, only 23% of the sinus wall was covered by adventitial layer, in contrast to 65% reported in laboratory animals. Unilaminar sinuses, with no adventitial coverage, accounted for greater than 38% of all sinuses. Quantitative analysis indicated that 60% of the latter sinuses contained apertures, as opposed to 35% of sinuses with adventitial coverage (P less than 0.05). Moreover, the number of apertures in unilaminar sinuses was significantly (P less than 0.009) greater than that in multilaminar sinuses. Apertures were observed every 59 microns in unilaminar sinuses, in contrast to every 109 microns in multilaminar sinuses. Approximately 75% of the apertures were occupied by cells in transit, and only 25% were free of cells. Macrophages were distributed throughout the marrow and were closely associated with all blood cell lines. Occasionally, cells that entered the lumen were not fully mature. Erythroblasts were seen migrating across the wall and within the lumen of sinuses. The less-extensive adventitial coverage in canine bone marrow might indicate that the rate of cell delivery from the marrow into the circulation was relatively high in this species.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

The blocked bed: a prospective study.

A prospective study of all patients (15 years and over) admitted to acute medical beds at a medium sized general hospital was carried out. For each patient, demogaphic data, day and time of admission, consultant in charge and the main reason for admission, were recorded. The patients hospital stay was analysed to determine the extent of the bed blocking problem. Sixty-two percent of total days stay required acute medical intervention, 32% was spent receiving nursing care only, 4% paramedical activities and 3% awaiting outside medical consultations. The three major factors found to influence total days stay were age, living situation and reason for admission. Patients over 75 years, living alone or who were admitted with a cerebrovascular accident/for nursing care were identified as bed blockers. An age related geriatric service may speed up the recovery of these patients and result in a more appropriate use of hospital resources.

Acute Disease↗
PubMed1988

Accident and emergency department utilisation: a consumer survey.

A consumer survey of Hutt Hospital A and E department was carried out to determine demographic characteristics of attenders, their reasons for attending the department and the involvement of the GP in emergency care. Relative to population norms, the predominant users were males, aged 15-29 years, and Maoris. Ninety-one percent of attenders were registered with a GP, however 28% of these were not local practices. Out of hours contact with a GP was successful for 69%. Fifty percent of respondents considered the A and E department the most appropriate place for seeking treatment, mainly because of x-ray facilities. Other reasons given for attending were: availability (24%), accessibility (16%). Cost of GP services was a reason in only 9%. The survey indicates a need to educate the public on A and E department functions. General practitioners need to improve the public's perception of their availability and role in emergency service provision.

Accidents↗
PubMed1988

Anterior proliferative vitreoretinopathy.

During a four-year period, 53 of 92 eyes (58%) undergoing vitreoretinal surgery for a retinal detachment with proliferative vitreoretinopathy demonstrated anterior proliferative vitreoretinopathy. We classified anterior proliferative vitreoretinopathy according to tractional direction, location, extent, and severity. Initially, the eyes were treated with a high scleral buckle and laser endophotocoagulation as an adjunct to vitrectomy. Treatment then evolved into a direct approach in which the anterior proliferative tissue was surgically cut or excised. Of the 42 eyes followed up for at least six months, 25 (59%) were totally reattached and 18 (43%) had a visual acuity of 5/200 or better.

Adult↗
PubMed1988

Latent disseminated blastomycosis with choroidal involvement.

A 36-year-old man developed blurred vision and a cough five months after traveling to an area from where a large outbreak of acute blastomycosis had been reported. Examination revealed a left choroidal lesion in the macular region, skin lesions on the right calf, and a left lung apical infiltrate. Histopathologic examination of the skin lesion demonstrated a granulomatous inflammation and broad based, budding yeast characteristic of Blastomyces dermatitidis. Amphotericin B therapy produced a rapid resolution of both choroidal and pulmonary lesions. During a six-month follow-up, there was no evidence of recurrence.

Adult↗
PubMed1988

Massive intraocular hemorrhage associated with anticoagulation and age-related macular degeneration.

The clinicopathologic correlation of three eyes with massive intraocular hemorrhage in patients receiving anticoagulant therapy is reported. All three patients were apparently predisposed because of antecedent disciform macular degeneration. The hemorrhage arose from the extrachoroidal neovascular vessels within the disciform lesions and caused rupture of the retinal pigment epithelium with massive intraocular hemorrhage. Because of the risk of vision-threatening intraocular hemorrhage, patients with exudative macular degeneration requiring anticoagulant therapy should be managed by both ophthalmologists and internists.

Age Factors↗
PubMed1988

Cephalosporin-induced alterations in erythroid (CFU-E) and granulocyte-macrophage (CFU-GM) colony-forming capacity in canine bone marrow.

Cephalosporins are among the safest antibiotics. Nevertheless, hematologic abnormalities ranging from mono- to pancytopenia do occur, albeit infrequently, following their therapeutic use. Similar abnormalities to those reported in people have been seen in dogs given high doses of cephalosporins. As part of a study to define the latter thoroughly, we explored the effects of long-term, high-dose cephalosporin administration on canine marrow erythroid (CFU-E) and granulocyte-macrophage (CFU-GM) progenitor cells. Cefazedone (Refosporen, E. Merck, Darmstadt) was administered intravenously at doses of 540 to 840 mg/kg daily to 14 healthy beagle dogs for up to 4 months, or less if hematologic effects were evident earlier. Within 6 to 10 weeks, treated dogs developed pancytopenia (5/14), thrombocytopenia (11/14), moderate to severe neutropenia (8/14), and/or normocytic anemia (8/14). There was evidence of immune-mediated destruction of peripheral blood cells. All treated dogs exhibited a significant reduction in marrow colony-forming capacity, irrespective of whether peripheral cytopenia was present, with 12/14 showing decreased CFU-GM and 14/14 decreased CFU-E activity. Within a week following cessation of dosing, all affected dogs achieved hematologic remission as defined by restoration of the peripheral blood counts. However, despite this apparent recovery, both CFU-E and CFU-GM activities of the bone marrow remained depressed for at least another 8 months. We conclude that in dogs prolonged administration of high doses of cefazedone induced a persistent deficit of CFU-E and CFU-GM progenitor cells. The clinical relevance of this, if any, remains to be established.

Animals↗
PubMed1988

Photocoagulation to prevent retinal detachment in acute retinal necrosis.

Retinal detachment (RD) occurs in more than 50% of eyes with acute retinal necrosis (ARN) and is the leading cause of visual loss in this syndrome. In order to decrease the incidence of RD in ARN, the authors treated 12 eyes of 10 patients with prophylactic laser photocoagulation. Retinal detachment occurred in two eyes (17%). Over the same time period, seven eyes with ARN did not receive prophylactic laser treatment, most often because of dense vitreous debris, with a 67% rate of RD. Prophylactic photocoagulation treatment should be considered in the management of patients with ARN.

Acute Disease↗
PubMed1988

Results and prognostic factors in penetrating ocular injuries with retained intraocular foreign bodies.

Of 105 eyes with ocular injuries involving retained intraocular foreign bodies, 63 (60%) had a final visual acuity of 20/40 or better; 20 (19%) were 20/50 to 5/200; and 15 (14%) were worse than 5/200. Six eyes (6%) were enucleated. The extent of visual recovery was limited in selected cases by the characteristics of the initial injury. Multivariate analysis was used to identify prognostic factors. Predictive of a good visual outcome (greater than or equal to 20/40) were: (1) initial visual acuity better than 20/40 and (2) the need for only one or two operations in the treatment of the injury. Predictive of a poor visual outcome (less than 5/200) were: (1) initial visual acuity worse than 5/200 and (2) a wound 4 mm or longer in length, independent of wound location. The visual outcome in this series of patients was compared with other large series of intraocular foreign bodies reported before the development of vitreous microsurgical techniques. The percentage of patients with a visual outcome of 20/40 or better has remained the same, whereas the incidence of enucleation has diminished.

Adolescent↗
PubMed1988

Vitrectomy in the management of peripheral uveitis.

The natural history of peripheral uveitis may eventually lead to indications for vitreous surgery. Over a 7-year period, a consecutive series of 12 eyes in nine patients with peripheral uveitis underwent vitreous surgery. Indications for surgery included persistent dense vitreous inflammation, vitreous hemorrhage, traction retinal detachment (RD), and epiretinal membrane formation. Patients were followed for an average of 22 months. Six eyes (50%) required further surgery after the development of RD, recurrent vitreous hemorrhage, or cataract formation. The preoperative finding most frequently associated with postoperative complications was the presence of active neovascularization of the vitreous base. Final visual acuity ranged from 20/30 to 20/100 showing an average improvement of 5 Snellen lines. Persistent cystoid macular edema significantly limited visual improvement in five patients. Patients undergoing vitreous surgery for management of peripheral uveitis may show a significant degree of visual improvement though multiple operations may be required. Control of active neovascularization is an important factor in limiting postoperative complications and the need for further surgery.

Adolescent↗
PubMed1988

Perisilicone proliferation after vitrectomy for proliferative vitreoretinopathy.

From 1983 to 1986, silicone oil injections were used to treat 31 patients with retinal detachment (RD) and advanced proliferative vitreoretinopathy (PVR). In 19 eyes (61%), perisilicone proliferation (PSP) developed causing recurrent RDs in 15 eyes (49%). At an average of 5 weeks after surgery, PSP occurred and was characterized by extensive transparent preretinal membranes with denser focal areas. Microscopic examination of five preretinal membranes showed droplets of silicone oil and necrotic cells on the silicone side and glial or retinal pigment epithelial cells, or both, on the retinal side, often in layers separated by extracellular matrix. Silicone oil was present in periretinal membranes removed several months after the intraocular silicone had been evacuated indicating that silicone within cells may persist despite the removal of silicone. The use of silicone oil to provide tamponade in eyes with recurrent PVR is associated with a high incidence of periretinal proliferation that frequently leads to recurrent RD and visual failure.

Adolescent↗