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Biomedical subjects

C Fowler

Publications and source records attributed to C Fowler.

At least 19 recordsLinked to original sources
PubMed1999

Reflective meniscometry: a non-invasive method to measure tear meniscus curvature.

AIMS: To devise a method to measure tear meniscus curvature by a non-invasive specular technique. METHODS: A photographic system was devised. The system consisted of a camera and an illuminated target with a series of black and white stripes oriented parallel to the axis of the lower tear meniscus. The target was mounted on a flash gun close to the objective of a Brown macrocamera and calibrated using a graduated series of glass capillaries of known diameter, ground down to expose the inner wall. It was then applied to normal human eyes (n = 45) to measure the tear meniscus curvature. A video system was also assessed which provided qualitative online information about the tear meniscus. RESULTS: Using the photographic system, measured values for capillary radii were in excellent agreement with theoretical calculations (r2 = 0.996, p < 0.0001). The radii of curvature of lower tear menisci in normal human subjects (mean 0.365 (SD 0.153) mm, range 0.128-0.736; n = 45) were similar to those reported in the literature. Both systems demonstrated variations in meniscus shape. The video system provided stable images of human menisci over prolonged periods of time and promises to be useful for the analysis of dynamic changes in meniscus volume. CONCLUSIONS: Reflective meniscometry is a non-invasive technique providing quantitative information about tear meniscus shape and volume and of potential value in the study of ocular surface disease.

Calibration↗
PubMed1998

Consensus statement on the diagnosis of multiple system atrophy. American Autonomic Society and American Academy of Neurology.

We report the results of a consensus conference on the diagnosis of multiple system atrophy (MSA). We describe the clinical features of the disease, which include four domains: autonomic failure/urinary dysfunction, parkinsonism and cerebellar ataxia, and corticospinal dysfunction. We set criteria to define the relative importance of these features. The diagnosis of possible MSA requires one criterion plus two features from separate domains. The diagnosis of probable MSA requires the criterion for autonomic failure/urinary dysfunction plus poor levodopa responsive parkinsonism or cerebellar ataxia. The diagnosis of definite MSA requires pathological confirmation.

Antiparkinson Agents↗
PubMed1998

A comparison of bone scintigraphy and MRI in the early diagnosis of the occult scaphoid waist fracture.

OBJECTIVE: To determine the accuracy of MRI in the assessment of the radiographically occult scaphoid fracture. DESIGN: This prospective study compared the sensitivity and specificity of MRI for detection of radiographically occult scaphoid fractures with bone scintigraphy (BS), the currently accepted imaging modality of choice. Consecutive patients with clinical signs of a scaphoid injury but no evidence of fracture on plain radiographs at presentation and after 7-10 days were evaluated by MRI and BS. All images were reported in masked fashion and the sensitivities and specificities of the imaging modalities determined. All patients with a scaphoid fracture demonstrated by MRI or BS were followed for at least a year after injury. PATIENTS: Forty-three subjects (aged 12-74 years) had both MRI and BS carried out on average 19 days from the injury date. RESULTS AND CONCLUSIONS: Six patients (14%) had scaphoid waist fractures. There were other bony injuries in a further six. In 40 patients there was agreement between the BS and MRI findings. In three cases there was discrepancy between the imaging modalities; in all three MRI was found to be the more sensitive and specific. MRI could become the investigation of choice for this injury.

Adolescent↗
PubMed1998

TBJ murine neuroblastoma resists dibutyryl cyclic AMP-induced differentiation and effects on metalloproteinase secretion.

BACKGROUND: Nonmetastatic C1300 murine neuroblastoma and TBJ, a metastatic variant, exhibit different mechanisms of metastasis and invasion. METHODS: In this study, they were examined for response to 1 mmol/L dibutyryl cyclic AMP in vitro. RESULTS: (1) dCAMP induced morphological differentiation in 20% to 40% of C1300 cells, whereas TBJ resisted differentiation. (2) Untreated TBJ expressed 92-kDa metalloproteinase, whereas C1300 expressed none. These results were not affected by dCAMP. (3) Growth curves of untreated C1300 and TBJ were exponential. Dibutyryl CAMP induced a plateau in C1300 growth that was confirmed by increased S-phase cells by cell cycle analysis. CONCLUSIONS: TBJ growth was unaffected by dCAMP. Apoptosis, as assayed by Hoechst-merocyanine staining test, was not involved in the growth plateau.

Animals↗
PubMed1998

Evaluation of the EyeSys model II computerized videokeratoscope. Part I: Clinical assessment.

PURPOSE: To compare the agreement and repeatability of keratometry measurements with simulated keratometry measurements from the EyeSys (model II) corneal analysis system (CAS). Furthermore, to establish any relationship between the repeatability of peripheral corneal measurements and the spatial location at the cornea. METHODS: Measurements using a Bausch & Lomb keratometer in 19 eyes (19 subjects) were compared with the simulated keratometry values using the EyeSys CAS. Repeatability of the keratometer (14 eyes, 14 subjects) and the EyeSys simulated keratometry values (10 eyes, 10 subjects) was assessed by comparing the difference of two measurements. Peripheral repeatability of the EyeSys CAS was compared in a similar manner in a sample of 10 eyes (10 subjects). RESULTS: The 95% confidence limits (-0.529 to +0.149 D) showed a lack of agreement between both instruments. With respect to the repeatability, both the keratometer (SD = +/- 0.103 D) and the EyeSys (SD = +/- 0.072 D) were found to exhibit approximately similar degrees of repeatability. The repeatability of peripheral corneal measurements using the EyeSys CAS showed changes in repeatability dependent on the corneal meridian and the distance from the point of alignment. Measurements along the superior and nasal meridians showed poorest repeatability. Repeatability was also found to deteriorate away from the point of alignment. CONCLUSIONS: EyeSys simulated keratometry values were not interchangeable with the keratometer. This could be due to differences in the method of alignment or measurements from different areas on the corneal surface. Repeatability of both the Bausch & Lomb keratometer and the EyeSys CAS was found to be similar. The spatial dependency of peripheral corneal radius repeatability measurements could be attributed to interference of the ocular adnexa in those areas of measurement.

Cornea↗
PubMed1998

Evaluation of the EyeSys model II computerized videokeratoscope. Part II: The repeatability and accuracy in measuring convex aspheric surfaces.

PURPOSE: To evaluate the precision and repeatability of a Placido disc-based computerized videokeratoscope, using convex surfaces of varying eccentricities and apical radii designed to simulate the range of topographical variations of the human cornea, rather than the purely spherical surfaces used in most previous studies. METHODS: Form Talysurf analysis was used to verify the exact form of 12 Perspex convex surfaces. The EyeSys model II videokeratoscope was used to measure the sagittal radii of curvature twice at known points on each surface. The raw data tables were analyzed to assess the repeatability and accuracy for both central and peripheral points on each surface. The relationship between these factors and the eccentricity was investigated. RESULTS: For central radii the instrument showed high correlation (r = 0.996) between actual and measured values. There was a small instrumental bias of +0.042 mm and the 95% limits of agreement were narrow (+0.121 to -0.037 mm), indicating clinically acceptable accuracy. The accuracy decreased slightly as the p-value decreased (greater peripheral flattening). For peripheral radii, the overall accuracy compared well to central radii, with an average bias of +0.022 mm and maximum error in 95% of cases 0.083 mm (bias +1.96 x SD). However, for surfaces where p = 0.50, the bias was +0.049 and maximum error in 95% of cases 0.110 mm. Repeatability for the aspheric surfaces was shown to be high (SD +/- 0.01 mm in all quadrants). CONCLUSIONS: The accuracy of the EyeSys corneal analysis system (CAS) in measuring central and peripheral radius of curvature was shown to be dependent on the shape of the surface to be measured. For more rapidly flattening surfaces, a decrease in accuracy was found for both central and peripheral radius of curvature, which in clinical terms is thought acceptable.

Cornea↗
PubMed1998

Recent trends in progressive power lenses.

Despite having been first marketed in the 1950s, new designs of progressive addition spectacle lens continue to appear. Some of the recent patent literature is reviewed on the design of such lenses. As well as a number of improvements to general purpose designs, specifically to include aspheric surfaces for the distance portion of progressive lenses, the literature includes a recent patent on an improved version of the Alvarez lateral translation lens system. The optimisation of single vision lens forms in order to extend the depth of field for early presbyopes is also discussed.

Aged↗
PubMed1998

Assessing transitional phenomena with the transitional object memory probe.

Winnicott's concept of transitional relatedness has captured the interest of psychoanalysts because it provides an understanding of the dialectical process occurring between inner and outer reality, and by extension, between analyst and analysand. Clinical observations related to transitional phenomena have led the authors to develop a projective early memory probe that assesses transitional phenomena. The transitional object early memory probe was tested both for its empirical validity and for its clinical utility in psychodynamic psychotherapy. Construct validity was assessed by comparing memory scores to the Rorschach Transitional Object Scale, as well as to therapist ratings of patient behaviors. Results demonstrated moderate correlations between early memory scores and Rorschach scale scores. Equally important was the finding that early memory scores were significantly correlated with therapist ratings of key behavioral patterns in therapy. A case vignette highlights the clinical application of the transitional object probe in assessing the capacity for transitional relatedness. In this case, the data gleaned from the patient's memories provided the therapist with a sharper focus on their role in the patient's growing capacity for more vital and creative contact with reality.

Adult↗
PubMed1997

Affect regulation and affective experience: individual differences, group differences, and measurement using a Q-sort procedure.

This article describes the development of, and preliminary findings with, the Affect Regulation and Experience Q-Sort (the AREQ), an observer-based assessment of affect regulation and experience. In Study 1, 31 clinicians provided Q-sort descriptions of 90 patients. Factor scores correlated in predicted ways with criteria such as suicide attempts and hospitalizations, as well as with clinicians' ratings of functioning in a variety of domains. Correlations between prototype Q-sorts and actual Q-sort profiles for patients sharing a diagnosis (dysthymia, borderline personality disorder, and narcissistic personality disorder) also provided evidence for convergent and discriminant validity. The data also suggested the importance of distinguishing 2 kinds of negative affect that have very different correlates. Study 2 showed that the AREQ can be applied reliably using an interview that avoids many of the problems of self-report.

Adult↗
PubMed1996

Factors associated with the intent of firearm-related injuries in pediatric trauma patients.

OBJECTIVE: To examine the characteristics of unintentional and assaultive firearm-related pediatric injuries treated in trauma centers. DESIGN: Comparative analysis of patients 14 years or younger who were admitted to the trauma centers because of unintentional firearm-related injuries (n = 292) vs assaultive firearm-related injuries (n = 457). SETTING: Sixty-eight trauma centers or children's hospitals in the continental United States and Canada that reported data to the National Pediatric Trauma Registry from January 1, 1990, through December 31, 1994. MAIN OUTCOME MEASURES: Frequency distributions of firearm-related injuries in relation to intent and injury circumstances, odds ratios (ORs) on the intent of injury being assaultive, injury severity scales, and in-hospital fatality rates. RESULTS: The frequency of unintentional firearm-related injuries rose in the afternoons peaking between 4 and 5 PM; they predominantly occurred at home (89%). Assaultive firearm-related injuries peaked sharply between 8 and 9 PM and usually occurred on roads or in other public places (63%). About 3 times as many boys as girls were harmed in firearm-related injuries. Given a firearm-related injury resulting in admission to a trauma center, the adjusted OR of it being assaultive was 2.8 (95% confidence interval [CI], 1.6-4.6) if the victim was a girl, 4.9 (95% CI, 3.1-7.8) if the shooting occurred at night, 2.6 (95% CI, 1.6-4.2) if the shooting occurred on a weekday, and 21.1 (95% CI, 9.1-49.4) if the shooting occurred on a road. Injury patterns and severity were similar between patients with unintentional and assaultive injuries. Overall, 19% of the patients sustained head injuries, which contributed to 90% of the in-hospital deaths. CONCLUSIONS: Marked differences in injury circumstances exist between unintentional and assaultive firearm-related injuries among children. The late afternoon hours when many children have come home from school but their parents may still be working have the highest frequency of unintentional firearm-related injuries. The evening peak of assaultive injuries may be related to drug-related and gang-related violence. While it is important to reduce the access of firearms to children, school-based extracurricular and community-based social services should be considered in developing intervention programs.

Adolescent↗
PubMed1996

Quantitative and qualitative differences in growth, invasion and lung colonization of an anaplastic and a papillary human thyroid cancer cell line in vitro and in vivo.

Invasion and metastasis remain major reasons for failure of anti-cancer therapy. Cell lines derived from human carcinomas are frequently used to investigate the molecular mechanisms that underlie invasion and metastasis. Unfortunately many of these cell lines do not retain the malignant characteristics of their parental tumors. We therefore conducted a series of experiments in vivo and in vitro to identify which aspects of malignancy of a papillary (NPA'87) and an anaplastic (DR090-1) thyroid carcinoma were consistent with the pathology of the parental tumor types. We evaluated tumor growth, invasion and metastasis of DRO90-1 and NPA'87 in vivo following inoculation of the tumor cells under the dermis, under the renal capsule and into the lateral tail vein of nude mice. This evaluation in vivo showed that the anaplastic carcinoma had a faster growth rate compared with the papillary carcinoma. Furthermore, the papillary carcinoma cells could destroy and infiltrate surrounding tissue but were not capable of extravasation and colonization of lung tissue. The anaplastic cells formed lung nodules following injection into the tail vein of nude mice. This lung colonizing capability of DRO90-1 correlated with their capacity to secrete an active 62 kDa gelatinase and to migrate through reconstituted basement membrane in vitro.

Animals↗
PubMed1996

Neuromodulation of detrusor hyper-reflexia by functional magnetic stimulation of the sacral roots.

OBJECTIVE: To investigate the acute effects of functional magnetic stimulation (FMS) on detrusor hyper-reflexia using a multi-pulse magnetic stimulator. PATIENTS AND METHODS: Seven male patients with established and intractable detrusor hyper-reflexia following spinal cord injury were studied. No patient was on medication and none had had previous surgery for detrusor hyper-reflexia. After optimization of magnetic stimulation of S2-S4 sacral anterior roots by recording toe flexor electromyograms, unstable detrusor activity was provoked during cystometry by rapid infusion of fluid into the bladder. The provocation test produced consistent and predictable detrusor hyper-reflexia. On some provocations, supramaximal FMS at 20 pulses/s for 5 s was applied at detrusor pressures which were > 15 cmH2O. RESULTS: Following FMS there was an obvious acute suppression of detrusor hyper-reflexia. There was a profound reduction in detrusor contraction, as assessed by the area under the curves of detrusor pressure with time. CONCLUSIONS: Functional magnetic stimulation applied over the sacrum can profoundly suppress detrusor hyper-reflexia in man. It may provide a non-invasive method of assessing patients for implantable electrical neuromodulation devices and as a therapeutic option in its own right.

Adult↗