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Biomedical subjects

R J Simmons

Publications and source records attributed to R J Simmons.

At least 19 recordsLinked to original sources
PubMed2001

The appearance of a second genotype of Japanese encephalitis virus in the Australasian region.

In mid-January 2000, the reappearance of Japanese encephalitis (JE) virus activity in the Australasian region was first demonstrated by the isolation of JE virus from 3 sentinel pigs on Badu Island in the Torres Strait. Further evidence of JE virus activity was revealed through the isolation of JE virus from Culex gelidus mosquitoes collected on Badu Island and the detection of specific JE virus neutralizing antibodies in 3 pigs from Saint Pauls community on Moa Island. Nucleotide sequencing and phylogenetic analyses of the premembrane and envelope genes were performed which showed that both the pig and mosquito JE virus isolates (TS00 and TS4152, respectively) clustered in genotype I, along with northern Thai, Cambodian, and Korean isolates. All previous Australasian JE virus isolates belong to genotype II, along with Malaysian and Indonesian isolates. Therefore, for the first time, the appearance and transmission of a second genotype of JE virus in the Australasian region has been demonstrated.

Animals↗
PubMed1998

Intraocular pressure control after contact transscleral diode cyclophotocoagulation in eyes with intractable glaucoma.

PURPOSE: The effect of contact transscleral diode cyclophotocoagulation (TDC) on intraocular pressure (IOP) and its safety was determined in eyes with intractable glaucoma. METHODS: The charts of 41 consecutive patients (43 eyes) who underwent the laser procedure were reviewed. After surgery, data were collected from chart entries at I hour, 1 day, 4 to 6 weeks, 4 to 6 months, and at the final visit (6-24 months). Mean differences in IOP before and after treatment were compared using the paired Student t test. Associated complications also were assessed. RESULTS: The mean +/- standard deviation follow-up period was 11.9+/-5.3 months (range, 6-24 months). One patient who died after 1 month of follow-up and another patient with neovascular glaucoma who underwent an anterior chamber washout 1 week after laser to treat an uncontrolled IOP spike were excluded from the study. Repeat treatment was done in 12 (28%) eyes. At each follow-up visit postoperatively, a significant reduction from preoperative IOP was obtained (mean reduction of 50% at the final visit). At the final visit, 64% of patients achieved an IOP of <22 mmHg and a reduction of > or =20%. An IOP spike occurred in three (7%) eyes. Long-term complications included loss of vision (> or =2 lines) in eight (22%) patients, corneal decompensation in one (2%), phthisis bulbi in one (2%), and corneal graft rejection in one (2%). CONCLUSION: Although effective IOP reduction was demonstrated in eyes with intractable glaucoma after TDC, a significant proportion (26%) of eyes had severe long-term complications.

Adolescent↗
PubMed1997

Prediction of preschool behavioral problems in healthy and pediatric samples.

In a prospective study of 137 children (47 with cystic fibrosis, 48 with congenital heart disease, 42 with no chronic illness), four domains were examined as predictors of parent-reported behavioral problems, particularly internalizing problems, at 4 years of age: child health, child temperament, parent-child relationships, and family environment. Family environment, as measured by the Parenting Stress Index at 1,2, and 3 years, was the most powerful predictor. This suggests that this index is useful as an early screen for children at risk for behavioral problems and that a reduction of parenting stress is an appropriate target of preventive interventions.

Adult↗
PubMed1997

Cataract extraction as a means of treating postfiltration hypotony maculopathy.

Hypotony maculopathy may arise after glaucoma filtering surgery. This can be treated by inducing inflammation and scarring within the filter, with the aim of increasing intraocular pressure (IOP) and promoting resolution of maculopathy. Cataract extraction can promote such inflammation. Phacoemulsification with posterior chamber intraocular lens (PC IOL) implantation was performed in two consecutive patients with postfiltration hypotony maculopathy and preexisting cataracts. After cataract extraction, improvement of IOP, visual acuity, maculopathy, and metamorphopsia occurred in both patients. Cataract extraction can be beneficial in the management of postfiltration hypotony maculopathy.

Cataract Extraction↗
PubMed1997

Midterm reversible failure in trabeculectomies with adjunctive mitomycin-C.

BACKGROUND AND OBJECTIVES: Trabeculectomies usually fail early (< 21 days) or late (> 6 months) when no antifibrotic agent is used. Failure is uncommon during the midterm period, between 3 weeks and 6 months. The purpose of this study is to verify the incidence of failure of trabeculectomies with mitomycin-C (MMC) during the midterm period and to evaluate the safety and efficacy of laser suture lysis (LSL) for reversing it. PATIENTS AND METHODS: The authors reviewed the records of 130 consecutive patients who underwent trabeculectomy with adjunctive MMC. RESULTS: Fourteen patients (15 eyes) had increased intraocular pressure (IOP), between 21 and 185 days (median 41 days). LSL was effective in decreasing the IOP to acceptable levels in 10 (66.6%) of the 15 eyes. No complications related to LSL were noticed. CONCLUSION: The reversibility of midterm failure seems to be a unique feature of trabeculectomies with MMC.

Adult↗
PubMed1997

An experimental study of airbag impact to the orbit using an instrumented Hybrid III headform.

This paper provides the results from an experimental study intended to assess airbag impact to the orbit. Twenty-seven airbags were deployed onto an instrumented Hybrid III headform. Seven different types of airbags were used that included tethered and nontethered, light to heavy nylon weaves, and different coating types. The airbags were deployed via a pneumatic deployment system. Seven individual force transducers, each having a 2.25 cm2 contact area, were placed on the right orbital region to evaluate the force patterns. The midpoint of the two ocular regions of the headform was positioned 12.5 cm above and 15.0 cm away from the center of the airbag, a position determined from previous airbag deployments to yield the highest leading edge velocity. The average maximum force per sensor ranged from 15.4 N to 63.6 N, and peak pressure ranged from 68 kPa to 282 kPa. The upper center of the orbit presented the highest values while the center of the orbit recorded the lowest values, a comparison that was proven to be statistically significant. For this configuration, the maximum force on the ocular region was found to be independent of the presence of a tether or the maximum internal airbag pressure.

Air Bags↗
PubMed1997

Airbag-induced eye injuries: experiments with in situ cadaver eyes.

In an attempt to investigate eye injuries from airbags, a set of experiments was performed that involved the deployment of several types of airbags onto thirteen unembalmed, previously frozen cadaver heads. The airbags differed in the material, coating, presence of a tether, and folding pattern, and were deployed via a pneumatic deployment system. The eyes were impacted in situ after being repressureized with saline injected through a 30-gauge needle. Injury determination was achieved by ophthalmic ultrasound imaging, staining with fluorescein dye, and dissection. All twenty-six eyes revealed detached retinas, as shown by the ultrasound, before impact as a result of decaying tissue and the freezing process. High speed video and film were used to capture the events. The impact velocities of the airbags were recorded from the digitized film at the first contact location with the eye and ranged from 30 m/s to 66 m/s. Eyeglasses were placed on four of the specimens, and the presence of eyeglasses seemed to provide protection to the eye because of the lack of contact between the airbag and ocular region. Minimal ocular damage was recorded for all experiments.

Air Bags↗
PubMed1996

Airbag-induced eye injuries: a report of 25 cases.

OBJECTIVE: To acquire a better understanding of airbag-induced eye injuries, 25 cases are reviewed and an attempt is made to identify the causal mechanisms associated with each injury. DESIGN AND METHODS: The National Highway Traffic Safety Administration's National Accident Sampling System for the years 1984-1994 was accessed to identify automobile accidents that included airbag deployment and injury to the ocular region. The search provided 25 such cases with detailed studies of the accident scene and medical records of the injuries. The cases were comprehensively reviewed to determine the casual mechanisms associated with each group of injuries. RESULTS: The study determined that the injuries range from mild corneal abrasions to retinal detachment. Causation for each injury was determined and is detailed. The injuries were grouped according to location within the ocular region, and the distribution is shown. CONCLUSIONS: Most of the injuries were induced by impact with the fully deployed airbag, but the more severe ocular trauma resulted from the actively deploying airbag striking the occupant. Thus, ocular trauma from airbags can occur in very minor impacts. Additionally, the left eye seemed more vulnerable to injury than the right. Nontethered airbags have greater inflation distances that tend to increase the probability of injury. External parameters that may also increase the severity of eye injury include an unfastened seat belt, sitting too close to the steering wheel, or wearing glasses.

Accidents, Traffic↗
PubMed1995

Can back supports relieve the load on the lumbar spine for employees engaged in industrial operations?

In recent years, there has been an increased use of back supports in US industry to reduce the frequency and concomitant costs of lower-back disorders. The obvious question is, 'Can back supports relieve the load on the lumbar spine for employees engaged in industrial operations?'. This paper is directed towards answering this question because there have been mixed conclusions in the literature reporting on the efficacy of back supports. The literature concerning the biomechanical, physiological and psychophysical effects of back supports on the human spine has been reviewed as well as the use of back supports to control injury in the workplace. A critical assessment of the findings reported by various investigators has been made together with a discussion of the mechanisms used by the trunk muscles to provide extrinsic stability to the spine. It is hypothesized that the extrinsic stability of the spine is manifested through more than one mechanism. These mechanisms may act simultaneously or sequentially to stabilize the trunk. Finally, the ergonomics of back supports as a corporate policy are discussed.

Humans↗
PubMed1995

Infant-mother attachment and nutrition in children with cystic fibrosis.

The association between nutritional status (percentage of weight for height) and infant-mother relationship was studied over 4 years in 38 children diagnosed with cystic fibrosis in the first year of life. Infant-mother relationship was assessed in a standardized laboratory observation. Although they could not be distinguished medically from the others at the time of diagnosis, infants showing a specific form of insecure relationship with their mothers (insecure-avoidant) differed from the others in: (1) failure to improve in nutritional status in the first year; (2) continuing decline in weight for height in the first 3 years; and (3) significantly lower weight for height at 1, 2, and 3 years of age. These data suggest that attention to mother-infant relationships, particularly feeding interactions, may improve nutritional status in children with cystic fibrosis.

Activities of Daily Living↗
PubMed1994

Using donor sclera to create a flap in glaucoma filtering procedures.

We report a surgical technique in which donor sclera is used to create a flap in glaucoma filtering procedures. This simple technique is helpful when the sclera is too thin to safely and effectively form an adequate scleral flap. The use of donor sclera allows the procedure to continue as a guarded procedure and prevents early postoperative hypotony.

Aged↗
PubMed1993

Can visual perception be used to estimate body part angles?

For two decades, observational methods have been used to measure postural loads in industry. These methods depend on the analyst's judgment to characterize correctly the working postures. The errors associated with estimating the body part's angular deviation from the neutral position are not known. Recently, videotaping of a work situation, followed by examination of the tape to assess postural position has become more commonly practised. This study was conducted to determine the error which accompanies the judging (without tools) of postural angles. In the present study, a method was used whereby 20 subjects were asked to report the perceived angles which closely matched the actual shoulder flexion angle displayed on the TV screen. The results showed no significant differences among the three angular ranges ('low', 1-60 degrees; 'medium', 61-120 degrees; and 'high', 121-180 degrees) of shoulder flexion, in terms of algebraic and absolute errors. Subjects tended to slightly overestimate the true angle in the low range and to slightly underestimate the true angle in the medium and high angle ranges. This study suggests that visual perception can be used to estimate shoulder flexion angles displayed on a VDT.

Adult↗