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Biomedical subjects

J G Ford

Publications and source records attributed to J G Ford.

33 records · Page 2Linked to original sources
PubMed1997

Bilateral monocular diplopia associated with lid position during near work.

PURPOSE: To describe a common pattern of topographic changes and clinical signs of six patients presenting with a complaint of monocular diplopia after reading and to investigate the cause of this topographic disturbance. METHODS PATIENT POPULATION: Subject group of six patients with monocular diplopia complaints after reading and 20 patients without such complaints. Examinations performed before and after a reading period of 30 min: videokeratoscopic examination, red reflex examination, position of the lids in primary gaze and in reading position. DATA ANALYSIS: inspection of keratoscopic rings, qualitative analysis of topography maps, comparison of SAI and SRI of control and subject groups before and after reading, comparison of lid position of control and subject group. RESULTS: Half of the subject group and none of the control group developed subtle ring distortions of keratoscopic rings. SAI and SRI values increased significantly in the subject group compared with the control group (p = 0.02 and p < 0.001, respectively) corresponding to the development of a focal distortion in the entrance pupil of the videokeratoscopic image. Each subject developed a horizontal band on red reflex located at the superior, middle, or inferior aspect of the pupil after near work. Two controls developed faint bands in the red reflex outside the entrance pupil. The interpalpebral fissure in down gaze was narrower in the subject group compared with the control group (p = 0.001). CONCLUSIONS: Some individuals may develop monocular diplopia after reading. We hypothesize that during near work these corneal topographic alterations occur primarily related to the position of the lids and tear film interaction with the corneal surface.

Adult↗
PubMed1995

Solid-phase hybridization capture of low-abundance target DNA sequences: application to the polymerase chain reaction detection of Mycobacterium paratuberculosis and Mycobacterium avium subsp. silvaticum.

Polymerase chain reaction (PCR) has been widely applied to the detection of microorganisms. Overall sensitivity of PCR tests may be substantially reduced due to a large excess of nontarget DNA and inhibitory substances in the sample. We used a 5'-biotinylated 513-bp probe from the 3' region of the IS 900 element specific for Mycobacterium paratuberculosis (Mptb) to capture target Mptb DNA from crude sample DNA extracts. Captured target DNA was separated using streptavidin-coated magnetic particles (Dynal). Since the IS 900 element shares homology over this region with IS 902 in Mycobacterium avium subsp. silvaticum (Mavs), target DNA from this other pathogen was also retained. Highly specific PCR for the detection of either organism directed to the 5' regions of IS 900 or IS 902 was then performed directly on the solid phase. Hybridization capture of target DNA using sequence adjacent to the desired specific PCR site applied to Mptb increased overall sensitivity of detection in tissue and fecal extracts 10- to 100-fold. False positives due to contamination artifact were substantially excluded since the capture probe did not retain amplicons from the detection PCR. Development of the method to involve covalent 5' immobilization of capture probes on heat-resistant polymers should, in the future, provide a simple system with broad potential applications.

Animals↗
PubMed1995

Topical 5-fluorouracil in treating epithelial neoplasia of the conjunctiva and cornea.

PURPOSES: To evaluate the efficacy of topical 5-fluorouracil (5-FU) in treating conjunctival and corneal epithelial neoplasia. METHODS: Three patients underwent surgical excision of bulky disease followed by topical 1% 5-FU in artificial tear base for 2 to 3 weeks or until epithelial separation occurred. An additional three patients underwent treatment with topical 1% 5-FU alone. RESULTS: Minimum follow-up was 6 months. In one patient with conjunctival in situ carcinoma and no detectable normal conjunctiva, who had normal findings on conjunctival histologic examination after application of topical 5-FU, a focus of invasive disease requiring orbital exenteration. One patient had a favorable response to 5-FU therapy but required a repeat excision for control of bulky disease. Four patients have remained disease-free for 10, 13, 18, and 30 months after topical 5-FU therapy. CONCLUSION: With its potential selective toxicity on dysplastic epithelium, topical 5-FU shows promise as an adjunctive treatment for managing conjunctival and corneal epithelial neoplasia.

Administration, Topical↗
PubMed1995

Central visual field changes associated with acquired pits of the optic nerve.

BACKGROUND: With the increased use of a hand-held indirect lens and slit-lamp biomicroscopy for stereoscopic viewing of the optic nerve, the authors believe that an acquired pit of the optic nerve is more common than was recognized previously. This increased recognition has led to the awareness that the central visual field was affected frequently in the presence of such an acquired pit. METHODS: The authors retrieved the charts of a series of 97 patients who had an acquired pit of the optic nerve during an 18-month period and retrospectively reviewed the automated visual fields associated with these pits using the Humphrey Visual Field Analyzer Programs 30-2 and 10-2 and looked for involvement of the central visual field. RESULTS: In 81.7% of the acquired pits of the optic nerves, one of the central-most test points (3 degrees from fixation) in the appropriate hemifield on the 30-2 format was depressed severely by Statpac II (P < 0.5). The authors therefore restudied as many patients as possible using the 10-2 format to determine the extent of central visual field involvement in the presence of an acquired optic nerve pit. Among these patients, the 10-2 format demonstrated that the approach of the defect to fixation varied, but was frequently inside 3 degrees, reaching between 1 degrees and 3 degrees from fixation in 96.7% of the eyes with depression of at least one central point on the 30-2 format. It was more likely that an acquired pit located at the inferior pole of the optic nerve would produce a visual field defect within 3 degrees of fixation than such a pit at the superior pole (P = 0.03). CONCLUSION: The authors showed that the presence of an acquired pit in an optic nerve damaged by glaucoma frequently is associated with a threat to fixation.

Adult↗
PubMed1990

Penetrating pellet fragmentation. A complication of ocular shotgun injury.

In three patients who had double-perforating ocular shotgun injuries, a single lead shotgun pellet apparently fragmented after striking the eye, resulting in two separate intraocular impact sites. The importance of detecting double-perforating eye injury and becoming aware of this potential complication with ocular shotgun injuries is emphasized.

Adolescent↗
PubMedDate not supplied

Long-acting beta2-agonist monotherapy vs continued therapy with inhaled corticosteroids in patients with persistent asthma: a randomized controlled trial.

CONTEXT: Long-acting beta(2)-agonists are prescribed for patients with persistent asthma and are sometimes used without inhaled corticosteroids (ICSs). No evidence exists, however, to support their use as monotherapy in adults with persistent asthma. OBJECTIVE: To examine the effectiveness of salmeterol xinafoate, a long-acting beta(2)-agonist, as replacement therapy in patients whose asthma is well controlled by low-dose triamcinolone acetonide, an ICS. DESIGN AND SETTING: A 28-week, randomized, blinded, placebo-controlled, parallel group trial conducted at 6 National Institutes of Health-sponsored, university-based ambulatory care centers from February 1997 to January 1999. PARTICIPANTS: One hundred sixty-four patients aged 12 through 65 years with persistent asthma that was well controlled during a 6-week run-in period of treatment with inhaled triamcinolone (400 microg twice per day). INTERVENTIONS: Patients were randomly assigned to continue triamcinolone therapy (400 microg twice per day; n = 54) or switch to salmeterol (42 microg twice per day; n = 54) or to placebo (n = 56) for 16 weeks, after which all patients received placebo for an additional 6-week run-out period. MAIN OUTCOME MEASURES: Change in morning and evening peak expiratory flow (PEF), forced expiratory volume in 1 second (FEV(1)), self-assessed asthma symptom scores, rescue albuterol use, asthma-specific quality-of-life scores, treatment failure, asthma exacerbation, bronchial reactivity, and markers of airway inflammation, compared among the 3 treatment groups. RESULTS: During the 16-week randomized treatment period, no significant differences between the salmeterol and triamcinolone groups were observed for conventional outcomes of clinical studies of asthma therapy-morning PEF, evening PEF, asthma symptom scores, rescue albuterol sulfate use, or quality of life. Both active treatments were superior to placebo. However, the salmeterol group had more treatment failures than the triamcinolone group (13/54 [24%] vs 3/54 [6%]; P =.004), as well as more asthma exacerbations (11/54 [20%] vs 4/54 [7%]; P =.04), greater increases in median (interquartile range) sputum eosinophils (2.4% [0.0% to 10.6%] vs -0.1% [-0.7% to 0.3%]; P<.001), eosinophil cationic protein (71 [-2 to 430] U/L vs -4 [-31 to 56] U/L; P =.005), and tryptase (3.1 [2.1 to 7.6] ng/mL vs 0.0 [0.0 to 0.7] ng/mL; P<.001). The duration of benefit when patients were switched from active treatment to placebo after 22 weeks of randomized treatment was not significantly longer in the triamcinolone group than in the salmeterol group. CONCLUSIONS: Patients with persistent asthma well controlled by low doses of triamcinolone cannot be switched to salmeterol monotherapy without risk of clinically significant loss of asthma control.

Administration, Inhalation↗
PubMedDate not supplied

Inhaled corticosteroid reduction and elimination in patients with persistent asthma receiving salmeterol: a randomized controlled trial.

CONTEXT: Inhaled long-acting beta(2)-agonists improve asthma control when added to inhaled corticosteroid (ICS) therapy. OBJECTIVE: To determine whether ICS therapy can be reduced or eliminated in patients with persistent asthma after adding a long-acting beta(2)-agonist to their treatment regimen. DESIGN AND SETTING: A 24-week randomized, controlled, blinded, double-dummy, parallel-group trial conducted at 6 National Institutes of Health-sponsored, university-based ambulatory care centers from February 1997 through January 1999. PARTICIPANTS: One hundred seventy-five patients aged 12 through 65 years with persistent asthma that was suboptimally controlled during a 6-week run-in period of treatment with inhaled triamcinolone acetonide (400 microg twice per day). INTERVENTION: Patients continued triamcinolone therapy and were randomly assigned to receive add-on therapy with either placebo (placebo-minus group, n = 21) or salmeterol xinafoate, 42 microg twice per day (n = 154) for 2 weeks. The entire placebo-minus group was assigned and half of the salmeterol group (salmeterol-minus group) was randomly assigned to reduce by 50% (for 8 weeks) then eliminate (for 8 weeks) triamcinolone treatment. The other half of the salmeterol group (salmeterol-plus group) was randomly assigned to continue both salmeterol and triamcinolone for the remaining 16 weeks (active control group). MAIN OUTCOME MEASURE: Time to asthma treatment failure in patients receiving salmeterol. RESULTS: Treatment failure occurred in 8.3% (95% confidence interval [CI], 2%-15%) of the salmeterol-minus group 8 weeks after triamcinolone treatment was reduced compared with 2.8% (95% CI, 0%-7%) of the salmeterol-plus group during the same period. Treatment failure occurred in 46.3% (95% CI, 34%-59%) of the salmeterol-minus group 8 weeks after triamcinolone therapy was eliminated compared with 13.7% (95% CI, 5%-22%) of the salmeterol-plus group. The relative risk (95% CI) of treatment failure at the end of the triamcinolone elimination phase in the salmeterol-minus group was 4.3 (2.0-9.2) compared with the salmeterol-plus group (P<.001). CONCLUSIONS: Our results indicate that in patients with persistent asthma suboptimally controlled by triamcinolone therapy alone but whose asthma symptoms improve after addition of salmeterol, a substantial reduction (50%) in triamcinolone dose can occur without a significant loss of asthma control. However, total elimination of triamcinolone therapy results in a significant deterioration in asthma control and, therefore, cannot be recommended.

Administration, Inhalation↗
PubMedDate not supplied

Effect of polymorphism of the beta(2)-adrenergic receptor on response to regular use of albuterol in asthma.

BACKGROUND: Regular use of inhaled beta-adrenergic agonists may have adverse effects in some asthma patients. Polymorphisms of the beta(2)-adrenergic receptor (beta(2)-AR) can affect its regulation; however, results of smaller studies of the effects of such polymorphisms on response to beta-agonist therapy have been inconsistent. METHODS: We examined the possible effects of polymorphisms at codons 16 (beta(2)-AR-16) and 27 (beta(2)-AR-27) on response to albuterol by genotyping 190 asthmatics who had participated in a trial of regular versus as-needed albuterol use. RESULTS: During the 16-week treatment period, patients homozygous for arginine (Arg/Arg) at beta(2)-AR-16 who used albuterol regularly had a small decline in morning peak expiratory flow (AM PEF). This effect was magnified during a 4-week run-out period, when all patients returned to as-needed albuterol only. By the end of the study, Arg/Arg subjects who had used albuterol regularly had an AM PEF 30.5 +/- 12.1 liters/min lower (p = 0.012) than Arg/Arg patients who had used albuterol as needed only. Subjects homozygous for glycine at beta(2)-AR-16 showed no such decline. Evening PEF also declined in the Arg/Arg regular but not in as-need albuterol users. No significant differences between regular and as-needed treatment were associated with polymorphisms at beta(2)-AR-27. CONCLUSIONS: Polymorphisms of the beta(2)-AR may influence airway responses to regular inhaled beta-agonist treatment.

Adolescent↗
PubMedDate not supplied

Air pollution health risks: do class and race matter?

Air pollution is not spread evenly across demographic groups. Exposures and associated health risks appear to fall disproportionately on populations that are poor and nonwhite. Although scientific evidence documenting disparities in air pollution exposures, doses, and health effects is scant, the available data strongly support the contention that disadvantaged groups, many of whom are ethnic and racial minorities, routinely encounter levels of air pollution that are higher than average. The extent to which exposure differentials contribute to observed differences in health status by class and race is unknown, but worthy of further investigation. We recommend several steps, all of them feasible and most of them relatively inexpensive, to improve our understanding and ability to address environmental health disparities.

Air Pollution↗
PubMedDate not supplied

Wound healing following anterior keratectomy and lamellar keratoplasty in the pig.

PURPOSE: To examine corneal wound healing in an animal model of two types of mechanical lamellar keratectomy. METHODS: One eye from each of 28 pigs was studied. Using a motorized keratome, corneas were subjected to an anterior lamellar keratectomy with removal of anterior stroma and epithelium, or to automated lamellar keratoplasty (ALK) with reapposition of a corneal flap. The exposed stromal surfaces were labeled intraoperatively with a fluorescent dye (DTAF) to assess deposition of stromal components during subsequent wound healing. Examination before surgery and enucleation included measurement of corneal curvature and intraocular pressure, and assessment of corneal haze. Eyes were prepared for histological examination, fluorescence microscopy, and for fibronectin immunohistochemistry. RESULTS: Both keratectomy procedures produced flattening of corneas by up to 3.80 diopters, 28 days after surgery. Corneal haze was more pronounced in eyes from which epithelium was removed (anterior lamellar keratectomy group). The increased haze in this group was associated histologically with appearance of many reactive keratocytes and inflammatory cells, deposition of new stromal material, and more widespread appearance of fibronectin immunoreactivity. In the lamellar keratoplasty group, only the edges of the corneal wound showed significant reactivity, and included keratocyte activation and epithelial ingrowth. CONCLUSIONS: The pig provides a useful model for studies of refractive surgical techniques using procedures and instruments designed for use in humans. Mechanized keratectomy procedures that minimize disruption of the epithelium and Bowman's layer produce a less reactive corneal wound than procedures in which an expanse of epithelium and anterior stroma are removed.

Animals↗
PubMedDate not supplied

Tuberculosis: pathogenesis and laboratory diagnosis.

Emerging molecular biologic technologies hold the promise of more rapid diagnosis of tuberculosis and more definitive epidemiologic linkages of cases of TB. In addition to reviewing the pathogenesis of tuberculosis, this chapter covers a variety of methods for the rapid detection of the disease, including the acid-fast smear, conventional culture, the BACTEC system, immunodiagnostic methods, and DNA-based techniques.

Clinical Laboratory Techniques↗