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Biomedical subjects

J L Davis

Publications and source records attributed to J L Davis.

At least 91 records · Page 5Linked to original sources
PubMed1994

Perioperative care of the pediatric trauma patient.

Children have specific emotional and physiological needs that are intensified when they sustain injuries that require surgery. Care of pediatric trauma patients includes the physiological considerations of airway management, hemodynamic stability, hypothermia, and physical size. Psychological considerations include enhancing coping skills, caring for children according to their developmental levels, and caring for family members. The perioperative nurse must be familiar with these pediatric trauma nursing principles to effectively meet the needs of children and their family members during times of trauma crisis.

Adolescent↗
PubMed1994

Retained lens fragments after phacoemulsification.

PURPOSE: The authors present the clinical features of patients with retained lens fragments after phacoemulsification and their outcome after pars plana vitrectomy. METHODS: The authors performed a retrospective chart review of 62 patients who had surgical management of posteriorly dislocated lens fragments after phacoemulsification during the 3-year period from January 1990 to December 1992. RESULTS: Eight of the 62 patients underwent vitrectomy on the same day as the cataract surgery. Of the remaining 54 patients examined in the outpatient clinic, initial clinical features included marked intraocular inflammation (87%), elevated intraocular pressure of 30 mmHg or higher (46%), and corneal edema (46%). Retinal detachment was present before vitrectomy in one patient and occurred after vitrectomy in two others. Initial visual acuity was 20/200 or worse in 68% of patients. After vitrectomy, final visual acuity was 20/40 or better in 68% of patients. Using the percentage of patients with 20/40 or better final visual acuity, there was no statistically significant difference in surgery performed within 7 days (70%), between 1 and 4 weeks (60%), and after 4 weeks (70%). Twenty (80%) of 25 patients with initial posterior chamber intraocular lenses (PC IOLs) and 16 (62%) of 26 patients with initial anterior chamber IOLs (AC IOLs) achieved 20/40 or better visual acuity. A visual acuity outcome of 20/200 or worse occurred in all three patients with retinal detachment. Six of the eight patients who underwent vitrectomy on the same day as the cataract surgery achieved 20/30 or better visual acuity. CONCLUSIONS: The timing of vitrectomy did not influence visual acuity outcomes. Intraocular lenses inserted at the primary operation did not adversely affect the visual outcome. However, vitrectomy on the same day as cataract surgery generally yielded favorable visual acuity outcomes and eliminated the need for a second operation at a later date. In most patients with retained lens fragments, management with vitrectomy allowed good visual acuity outcomes.

Aged↗
PubMed1993

Association of herpes zoster ophthalmicus with acquired immunodeficiency syndrome and acute retinal necrosis.

We conducted a review to investigate the prevalence of human immunodeficiency virus (HIV), or acquired immunodeficiency syndrome (AIDS), in patients with herpes zoster ophthalmicus, as well as the incidence of acute retinal necrosis after herpes zoster ophthalmicus. All charts of patients seen at our institution between 1987 and 1992 with a primary diagnosis of herpes zoster ophthalmicus were reviewed. Of 112 patients with herpes zoster ophthalmicus, 29 (26%) had HIV or AIDS. All these patients were younger than 50 years at the time of diagnosis. Five of 29 (17%) immunocompromised patients had acute retinal necrosis after herpes zoster ophthalmicus. No acute retinal necrosis was identified in the nonimmunocompromised patients after herpes zoster ophthalmicus. We recommend that all patients younger than 50 years who have herpes zoster ophthalmicus at initial examination be tested for HIV. Additionally, HIV-infected patients should be monitored closely after herpes zoster ophthalmicus for development of acute retinal necrosis. Long-term oral prophylactic as well as initial high-dose intravenous acyclovir may be appropriate in HIV-infected individuals with herpes zoster.

AIDS-Related Opportunistic Infections↗
PubMed1993

Morphologic and biomechanical comparison of tendons used as free grafts.

The palmaris longus (n = 10), plantaris (n = 11), and extensor digitorum longus (n = 10) tendons were harvested from cadaver limbs for morphologic and biomechanical comparisons. Eleven flexor digitorum profundus tendons from the index finger were also harvested for comparison of biomechanical properties of the free graft tendons with those of a typical digital flexor. Maximal tendon length, cross-sectional area, volume, stiffness, and modulus of elasticity were determined by measurement, laser micrometry, and tensile testing. The plantaris and extensor digitorum longus yielded the longest grafts, 334 and 325 mm, respectively, compared with the palmaris longus, which yielded only 161 mm of length. Cross-sectional areas were as follows: palmaris longus, 3.1 mm2; plantaris, 1.4 mm2; extensor digitorum longus, 3.3 mm2; and flexor digitorum profundus, 10.6 mm2. Mean volumes were as follows: palmaris longus, 529 mm3; plantaris, 557 mm3; and extensor digitorum longus, 1006 mm3. The palmaris longus and the extensor digitorum longus showed greater stiffness, 42.0 and 47.8 N/mm, respectively, than the plantaris, which had a stiffness of 25.5 N/mm. However, the flexor digitorum profundus showed significantly greater stiffness than all of the graft tendons. The modulus of elasticity ranged from 1161.6 to 1673.0 MPa, with no significant difference between tendons tested. The findings in this study provide data that may be useful in the selection of a specific donor for free tendon grafting.

Biomechanical Phenomena↗
PubMed1993

The role of chorioretinal biopsy in the management of posterior uveitis.

BACKGROUND: The ideal management of intraocular inflammation may require a tissue diagnosis. Diagnostic vitrectomy is a well-established method for acquiring such tissue. However, in some patients, the diagnostic pathology is limited to the choroid and retina and vitrectomy may yield no useful information. In such cases, a more aggressive surgical approach to obtain tissue may be useful. METHODS: The authors performed chorioretinal biopsies on seven patients with progressive chorioretinal lesions of unknown etiology. Indications for biopsy included: (1) macular-threatening lesions unresponsive to therapy, (2) suspicion of malignancy, or (3) suspicion of an infectious etiology. In all cases, it was expected that the results would alter therapy or other aspects of clinical care. Preoperative visual acuity was 20/200 or worse in each eye biopsied with one or more peripheral chorioretinal lesions present. Biopsy specimens were divided into three parts and submitted for light and electron microscopy, immunohistochemistry, and tissue culture. RESULTS: On the basis of the biopsy findings, a diagnosis of multifocal choroiditis and subretinal fibrosis was rendered in three eyes, sarcoidosis in two eyes, and viral retinitis in two eyes. Therapy was changed in five patients. Final visual acuity was unchanged or improved in five eyes. Complications included the progression of lens opacity in all eyes and the development of phthisis in one eye that was extensively diseased preoperatively. CONCLUSION: Chorioretinal biopsy may provide useful information for determining the diagnosis and guiding the subsequent management of patients with progressive chorioretinal lesions of unknown etiology.

Adult↗
PubMed1993

Postoperative Propionibacterium endophthalmitis. Treatment strategies and long-term results.

PURPOSE: Postoperative Propionibacterium endophthalmitis is a condition characterized by exacerbations and remissions that has often been accompanied by recurrence after treatment. The purpose of this study is to evaluate the efficacy of initial therapies in preventing recurrent endophthalmitis and to assess the safety of intraocular lens (IOL) exchange performed during treatment of active endophthalmitis. METHODS: The records of 22 patients with culture-proven Propionibacterium endophthalmitis treated at one facility were retrospectively reviewed. RESULTS: Two patients presented acutely, were treated with intraocular antibiotic injection alone, and experienced no recurrent inflammation. Twenty patients presented with chronic, delayed-onset pseudophakic endophthalmitis. Eight of these were treated initially with intraocular antibiotic injection alone, and recurrent endophthalmitis developed in seven. Twelve patients with chronic endophthalmitis were initially managed surgically with either pars plana vitrectomy or IOL exchange. Four of the 12 experienced recurrent endophthalmitis. Patients undergoing capsulectomy as part of initial management experienced the lowest rate of recurrent endophthalmitis. Eight patients eventually underwent total capsulectomy and IOL explantation, seven of whom had IOL exchange. None of these eight patients had recurrent endophthalmitis. In seven of the eight, persistent bacterial colonization of the lens capsular remnants was demonstrated. CONCLUSIONS: These data suggest that recurrent Propionibacterium endophthalmitis is due to persistence of viable organisms sequestered within lens capsular remnants, and that initial therapy directed toward surgical removal of these sequestered organisms results in a reduced frequency of recurrent endophthalmitis. Intraocular lens exchange with complete capsular removal during active endophthalmitis was not associated with recurrent or persistent endophthalmitis.

Acute Disease↗
PubMed1993

Response to Duffy.

Explore the source record for details and available documents.

Civil Rights↗
PubMed1992

Causes of reduced visual acuity on long-term follow-up after cataract extraction in patients with uveitis and juvenile rheumatoid arthritis.

We reviewed the long-term follow-up on a consecutive series of 16 eyes from ten patients with juvenile rheumatoid arthritis-associated cataracts that were removed by using pars plana lensectomy and vitrectomy. All patients had prominent cataracts, chronic uveitis, posterior synechiae, and vitreitis preoperatively, and had at least 12 months of follow-up postoperatively. The median length of follow-up was 51 months (range, 12 months to ten years). In the early postoperative period, a visual acuity of 20/70 or better was obtained in 13 of 16 eyes (81%). With longer follow-up, the final visual acuity was 20/70 or better in only nine of 16 eyes (56%). The primary categories of delayed visual loss in these cases were glaucoma and macular disease (chronic cystoid macular edema, macular hole, hypotony maculopathy, and recurrent macular pucker). Despite these limitations in maintaining good visual acuity, a pars plana lensectomy and vitrectomy approach is effective for cataracts in these patients with uveitis.

Adolescent↗
PubMed1992

Immunocytochemical staining of vitreous cells. Indications, techniques, and results.

Diagnostic vitrectomy is often performed because of suspected infection or malignancy. Giemsa, Gram, and Papanicolaou stains are used routinely to identify the components in the vitreous. Immunocytochemical staining of cellular components of vitreous specimens has the potential to significantly increase the amount of useful information that can be gained from histopathologic study. Vitreous specimens from 14 patients undergoing diagnostic or therapeutic vitrectomy for infection, suspected primary intraocular lymphoma, or uveitis were examined by immunocytochemical staining using monoclonal antibodies specific for leukocyte subclass antigens and immunoglobulin. The three classes of disorders showed characteristic patterns of staining, which were useful in confirming microbiologic and clinical diagnoses. Infections showed more pronounced neutrophils and macrophages, primary intraocular lymphomas demonstrated light chain restriction of the malignant B lymphocytes, and uveitis was characterized by the predominance of T lymphocytes. The routine use of immunocytochemical staining is recommended to characterize cellular infiltrates and increase the diagnostic yield from vitrectomy specimens.

Antibodies, Monoclonal↗
PubMed1992

Management of retinal detachment associated with CMV retinitis in AIDS patients.

In patients with AIDS, the most important ocular opportunistic infection, CMV retinitis, can now be treated effectively with virostatic agents. Associated retinal detachment is encountered frequently, and its management has become increasingly significant to quality of life as improvements in medical care have helped to preserve vision and extend life expectancy. Although retinal detachment in these eyes is typically rhegmatogenous, the pathophysiology is distinctive due to the association with CMV retinitis which, even in remission, is characterised by atrophic changes at all levels of affected retina and alterations of the vitreous. Despite initially successful surgical reattachment, multiple, small, often posterior holes may develop because of progressive CMV infection. For these reasons, vitrectomy and silicone oil injection with scleral buckling may currently provide the best overall means of maintaining retinal reattachment and restoring visual function. Nevertheless, management must be individualised in each case, with the realisation that progressive visual loss frequently ensues from retinitis progression.

AIDS-Related Opportunistic Infections↗
PubMed1992

A presumptive helicase (MOT1 gene product) affects gene expression and is required for viability in the yeast Saccharomyces cerevisiae.

Exposure of a haploid yeast cell to mating pheromone induces transcription of a set of genes. Induction is mediated through a cis-acting DNA sequence found upstream of all pheromone-responsive genes. Although the STE12 gene product binds specifically to this sequence element and is required for maximum levels of both basal and induced transcription, not all pheromone-responsive genes are regulated in an identical manner. To investigate whether additional factors may play a role in transcription of these genes, a genetic screen was used to identify mutants able to express pheromone-responsive genes constitutively in the absence of Ste12. In this way, we identified a recessive, single gene mutation (mot1, for modifier of transcription) which increases the basal level of expression of several, but not all, pheromone-responsive genes. The mot1-1 allele also relaxes the requirement for at least one other class of upstream activating sequence and enhances the expression of another gene not previously thought to be involved in the mating pathway. Cells carrying mot1-1 grow slowly at 30 degrees C and are inviable at 38 degrees C. The MOT1 gene was cloned by complementation of this temperature-sensitive lethality. Construction of a null allele confirmed that MOT1 is an essential gene. MOT1 residues on chromosome XVI and encodes a large protein of 1,867 amino acids which contains all seven of the conserved domains found in known and putative helicases. The product of MOT1 is strikingly homologous to the Saccharomyces cerevisiae SNF2/SW12 and RAD54 gene products over the entire helicase region.

Adenosine Triphosphatases↗
PubMed1992

Complications of smooth pin fixation of fractures and dislocations in the hand and wrist.

A retrospective review of patients treated with internal fixation of fractures or dislocations of the hand or wrist over a four-year period was undertaken to determine the complication rates of pin fixation for stabilization of these injuries. One hundred thirty-seven patients who received 422 pins were studied. All pins were unthreaded, measured 0.035-0.069 inches (0.9-1.8 mm) in diameter, were placed with a power drill, and were left protruding through the skin. The mean time that pins were left in place was 6.5 weeks, (range, two days to 24 weeks). Minimum follow-up time was 43 days after pin removal. Thirty-four complications occurred in 24 patients, and the overall complication rate was 18%. Forty-five of the 422 pins were involved (11%). Complications included infections in ten patients (7%), pin loosening without infection in six (4%), loss of reduction in six (4%), symptomatic nonunion in six (4%), impaled flexor tendon in two (2%), asymptomatic pseudarthrosis in one (1%), pin migration in one (1%), median nerve injury in one (1%), and radial artery injury in one (1%). Osteomyelitis developed in two of the patients with infections. Pin tract infection occurred at a mean time of ten weeks and aseptic loosening at a mean time of eight weeks. The frequent complication rates emphasize the need for meticulous pin placement, adequate intraoperative evaluation of pin position, and satisfactory patient compliance. Despite the frequency of these complications, serious permanent sequelae did not occur in most patients.

Bone Nails↗
PubMed1991

Role of chorioretinal biopsy in inflammatory eye disease.

Two patients who had similar clinical presentations of bilateral multiple chorioretinal lesions and needed a correct diagnosis underwent chorioretinal biopsy. The biopsy from one patient demonstrated mainly a B cell infiltrate in choroidal and subretinal nodules, while the biopsy from the second patient showed mainly macrophages in the retina. These findings directed the therapeutic approach taken in each patient. Although chorioretinal biopsy is an invasive procedure with the potential for serious complications, the resultant finding may aid in the diagnosis and guide the subsequent management of certain patients presenting with serious ocular findings of undefined etiology.

Biopsy↗