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Biomedical subjects

D Kurtz

Publications and source records attributed to D Kurtz.

At least 19 recordsLinked to original sources
PubMed2001

Tropicamide (1%): an effective cycloplegic agent for myopic children.

PURPOSE: To evaluate the cycloplegic effect of 1% tropicamide in myopic children and to determine whether its efficacy is associated with age, gender, iris color, ethnicity, magnitude of the refractive error, or latent error. METHODS: Four hundred sixty-nine children enrolled in the Correction of Myopia Evaluation Trial (COMET; a multicenter, randomized, double-masked clinical trial evaluating the rate of progression of juvenile-onset myopia in children wearing progressive-addition versus single-vision lenses) were given 1 drop of proparacaine in each eye followed 1 minute later by 1 drop of 1% tropicamide and then a second drop of 1% tropicamide 4 to 6 minutes later. Five accommodative responses to 20/100 letters located at 4 m and 33 cm were obtained in each eye with an autorefractor, 20 minutes after the second drop. Residual accommodation was calculated as the difference between the mean spherical equivalent responses obtained at the two distances. An examiner graded iris color, and ethnicity was reported by the children's parents or guardians. RESULTS: The mean residual accommodation was small: 0.38 +/- 0.41 diopters (D) in the right eye and 0.30 +/- 0.41 D in the left eye. Small but statistically significant differences in residual accommodation were associated with ethnicity, but not with any of the other factors. CONCLUSIONS: Tropicamide (1%) is an effective cycloplegic agent in myopic children.

Accommodation, Ocular↗
PubMed1998

Management of functional vision loss.

BACKGROUND: Functional vision loss is a general term used to describe vision loss not associated with organic disease. Such cases are major challenges to the practitioner and demand a special workup. METHODS: Patients may manifest symptoms in typical ways that should alert the examiner to the possibility of functional vision loss. In addition, a variety of techniques help distinguish functional from organic causes of vision loss. These techniques include standard tests that yield characteristic findings in functional vision loss, as well as problem-specific procedures that have the specific aim of detecting functional vision loss. Techniques are described according to whether they are useful in monocular or binocular vision loss and in cases of moderate or severe vision loss. RESULTS: Three cases that illustrate the use of standard and select techniques to detect functional vision loss are presented. Differential diagnosis of functional from organic vision loss and special considerations in the management of patients with functional vision loss are also discussed. CONCLUSIONS: Although it is necessary to rule out underlying pathology in all cases of vision loss, a variety of techniques can provide positive evidence of functional vision loss.

Adult↗
PubMed1996

[Auditory P300 in subjects in a post-anoxic coma. Preliminary data].

The first results concerning the role of event related potentials (P300) in assessing a prognosis in comatose patients reported in the literature have been encouraging. The cause of the coma is an important prognostic factor by itself, especially when traumatic and anoxic comas are compared, with a less favorable prognosis in anoxic coma. In our study, only anoxic patients have been investigated using somatosensory evoked potentials, brainstem auditory evoked potentials P300 auditory event-related potentials. Clinical evaluation was performed using Glasgow, Liege and Jouvet coma scales. In twenty patients studied, six had a positive P300 and three of them awake. Out of the 14 patients without a P300 only one awoke (5%), 12 patients died and one is in deep coma. Despite the small number of patients in this study, the first results confirm the interest of auditory P300, in addition to clinical evaluation and evoked potential testing.

Adult↗
PubMed1996

Long-term compliance with CPAP therapy in obstructive sleep apnea patients and in snorers.

A prospective study aimed at objectively evaluating compliance with nasal continuous positive airway pressure (CPAP) treatment was conducted in 728 obstructive sleep apnea [OSA; apnea/hypopnea index (AHI) > 15 events/hour] patients and 98 nonapneic snorers (AHI < or = 15 events/hour). Five-hundred seventy-five OSA patients and 33 nonapneic snorers underwent CPAP therapy and were followed-up for an average of 1,176 +/- 38 days (27 to 4,203 days). Compliance to treatment was measured by the mean rate of use of the CPAP device obtained from a built-in time counter. Acceptance of treatment was measured using Kaplan-Meier's model. The acceptance of CPAP was greater than 90% at 3 years and greater than 85% at 7 years in OSA patients. It was greater than 60% at 3 years in nonapneic snorers. The mean rate of CPAP use was 5.7 +/- 1.8 hours/day in OSA patients and 5.6 +/- 1.4 hours/day in snorers who were still on CPAP on October 1, 1995. It was correlated positively with age, body mass index, and AHI, and it was correlated negatively with daytime partial pressure of oxygen (PaO2), forced expiratory volume in 1 second (FEV1), and vital capacity in the group of OSA patients. This study shows that CPAP therapy is reasonably accepted by OSA patients as well as by nonapneic snorers. Both within and between groups, objective disease severity (as measured by the respiratory event index and daytime and nighttime hypoxemia), rather than patients' symptoms or complaints, seemed to play a role in the quality of compliance to treatment.

Body Mass Index↗
PubMed1996

An empirical study of the influence of demographic variable on the choice criteria for assisted living facilities.

Despite the growth and prevalence of assisted-living facilities, empirical marketing research for these facilities is scarce. The objectives of this study were to determine the relative importance of three sets of evaluation criteria in the initial selection of an assisted-living facility, and determine whether the relative importance of these three sets of criteria differed by gender, marital status, level of household, age, or income of the consumer. Survey responses from 279 households indicates that primary service criteria are relatively more important than facilities amenities or organized social activities in the initial selection of an assisted-living facility. The relative importance of the choice criteria differed markedly by gender of the consumer, but marital status, level of household income, and age of the consumer did not have as great an impact on consumers' choice criteria.

Age Factors↗
PubMed1996

Injection site effects on the pharmacokinetics and glucodynamics of insulin lispro and regular insulin.

OBJECTIVE: The pharmacokinetics and glucodynamics of a new insulin analog, insulin lispro, and regular human insulin were compared and contrasted after subcutaneous administrations in femoral, deltoid, and abdominal injection sites. RESEARCH DESIGN AND METHODS: Single 0.2 U/kg doses of insulin lispro and regular insulin were administered to 12 healthy subjects in a six-way randomized crossover fashion. Each dose was given after an overnight fast in one of three injection sites: abdominal, deltoid, or femoral. Study drugs were given during a manual euglycemic glucose clamp. Blood samples were collected over the 12-h clamp for measurement of insulin-reactive components, with pharmacokinetic and glucodynamic measurements derived from these serum insulin and clamp measurements. RESULTS: Glucodynamic comparisons between insulin lispro and regular insulin showed a greater maximum infusion rate (Rmax) at an earlier time (TRmax), regardless of injection site. The total glucose infused (Gtot) showed nearly identical values between sites for insulin lispro. Regular insulin showed greater Gtot values from deltoid and femoral injections. When comparisons were made between drugs, regular insulin produced significantly greater Gtot, primarily driven by the increased Gtot from deltoid and femoral injections. Greater maximum serum insulin concentrations (Cmax) were experienced with insulin lispro at earlier times (tmax), regardless of the injection site (P < 0.001). Abdominal administrations produced the greatest Cmax values at the earliest tmax for both regular insulin and insulin lispro. Deltoid and femoral injections had lower Cmax values for both compounds. Shifts also occurred with tmax, although these shifts were much greater with regular insulin than with insulin lispro. Equivalent area under the curve (AUC) values were found when compared between compounds. CONCLUSIONS: Slower absorption from deltoid and femoral administrations resulted in an increased duration of action for both regular insulin and insulin lispro when compared to abdominal administration. However, notable increases in the onset of action were only apparent with regular insulin. The consistency with insulin lispro response from abdominal and extremity injection sites allows more potential sites for subcutaneous injection with an assured rapid response.

Abdomen↗
PubMed1994

[Event-related potentials and language processing].

The contribution of cognitive event-related potentials (ERPs) and particularly of the N400 component to the study of language processing is considered. After a general presentation of the various components of cognitive evoked potentials which are differentiated from early potentials (sensitive to perceptive parameters), the neurophysiological and psychological correlates of ERPs are discussed. Before the presentation of the main studies concerned with the correlation between specific late components and linguistic processes, it is proposed an introduction to some theoretical models of language processing which serve as conceptual framework supporting most of the experimental approaches in this field. The results of EPs studies devoted to functional asymetries in language processing are briefly mentioned. Then a number of studies are analysed, these demonstrate the sensitivity of event-related potential measures to linguistic manipulations. Finally, the studies concerned with the N400 are reviewed, this potential appears to be the more specifically language-related ERP component, even if its connection with specific linguistic processes or its differentiation from N200 are still under debate. Nevertheless language-related electrophysiological investigations may become in the near future a useful complementary approach to our understanding of language processing and language disorders.

Brain↗
PubMed1994

Providing service and education through community outreach.

We have described several of the innovative ways in which the New England College of Optometry has addressed its goal of cultivating compassionate and ethical behavior in its students while providing them with unique educational opportunities. In these four projects the New England College of Optometry has taken its services to where those in need are located. All of these projects have received enthusiastic support from their host institutions and from the many clients and students who have benefited from their services.

Community Health Services↗
PubMed1992

Frequency of certain urgent eye problems in an emergency room in Massachusetts.

The frequency and cost of emergency room care for certain ocular problems was surveyed. Superficial eye problems accounted for 2.67 percent of patients reporting to the emergency room, while 0.23 percent reported for penetrating injuries. Of the conditions surveyed, conjunctivitis was the most commonly presenting diagnosis. Abrasions and superficial foreign bodies were the next most common presentations. Together these three diagnoses accounted for nearly 75 percent of all superficial eye problems seen in the emergency room. The cost of each emergency room visit averaged $132. This study has implications for health care managers and for legislatures contemplating expanding the scope of optometric practice.

Cost-Benefit Analysis↗
PubMed1991

Sleep and breathing abnormalities in a case of Prader-Willi syndrome. The effects of acute continuous positive airway pressure treatment.

This report describes the polysomnographic findings and the respiratory alterations during sleep in a 20-year-old patient with the Prader-Willi syndrome. Nocturnal recordings and a variant of the multiple sleep latency test showed excessive daytime sleepiness, sleep onset rapid eye movement episodes, snoring and sleep apnea. Treatment with nasal continuous positive airway pressure normalized the respiratory pattern and the sleep structure, except for rapid eye movement sleep onset. Whereas upper airway obstruction and obesity may explain the respiratory disorders, as shown by their resolution with continuous positive airway pressure treatment, hypothalamic dysfunction could play a role in the disruption of the normal nonrapid eye movement/rapid eye movement sleep periodicity.

Adult↗
PubMed1991

Left ventricular ejection fraction in obstructive sleep apnea. Effects of long-term treatment with nasal continuous positive airway pressure.

The effects of treatment with nasal continuous positive airway pressure (CPAP) on left ventricular ejection fraction (LVEF) were assessed in 29 patients with obstructive sleep apnea (OSA) in a prospective study using multiple gated equilibrium radionuclide angiocardiography. All patients were evaluated before CPAP treatment was initiated and were reevaluated after one year (mean +/- SE, 415 +/- 6 days), of home treatment with nasal CPAP. The mean LVEF increased from 59 +/- 1 percent to 63 +/- 1 percent (p less than 0.005). The degree of improvement in LVEF was correlated with baseline LVEF (r = 0.54; p less than 0.003), meaning that the lower the baseline value, the greater the increase with treatment. The changes were not different when subgroups of medicated and unmedicated patients were considered separately. These results show that long-term nasal CPAP treatment results in improved left ventricular function in OSA.

Evaluation Studies as Topic↗
PubMed1991

[Postures and abnormal paroxysmal movements during sleep: hypnogenic paroxysmal dystonia or partial epilepsy?].

In recent years, a differentiation has been made between two syndromes that are characterized by brief abnormal paroxysmal movements occurring principally at night: 1, hypnogenic paroxysmal dystonia (HPD), sometimes considered a particular form of dystonia similar to paroxysmal kinesigenic choreoathetosis, and 2, mesiofrontal epilepsy. Whether HPD is a distinct syndrome is not clear. Twenty-three patients, 11 men and 12 women, were hospitalized between 1985 and 1989 for examination of this type of abnormal paroxysmal movements (APM) occurring at night. In order to clarify the physiopathology of these abnormal nocturnal movement as focal epilepsy or a particular form of dystonia, we analyzed the personal and familial antecedents of all 23 patients, the polygraphic records during waking and sleep periods, and the results of neuroradiological examinations. Four patients were examined by positron emission tomography (PET) using i8F deoxyglucose. Symptoms first appeared between 3 and 28 years of age (M, 10.1) and developed over 1 to 20 years (M, 10.1). APM clearly occurred more commonly (greater than 90%) during sleep, usually during phases of slow-wave sleep. The sleeping patient opened his eyes and the motor signs then variously associated affective facial expression; axial postural modifications; tonic, dystonic or choreic postural movements of the limbs; pedalling; automatisms; disordered agitation and vocalization. The seizure was abruptly interrupted after 10 to 60 seconds. There was usually no postictal confusion. Thirteen patients clearly had clear epileptic antecedents: in 9, generalized tonic-clonic seizures; in 4, focal epileptic status. During nocturnal polygraphic recording, 6 patients presented a generalized seizure following a period of APM.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Frequency and mechanism of daytime pulmonary hypertension in patients with obstructive sleep apnoea syndrome.

In order to study the frequency and the mechanisms of daytime pulmonary hypertension (PH) in obstructive sleep apnoea syndrome (OSAS) lung function tests, blood gas analysis and right-heart catheterization were performed in 46 consecutive patients. OSAS was assessed by polysomnography. 9 patients only (20%) had PH (mean pulmonary artery pressure (Ppa) greater than or equal to 20 mmHg). Patients with PH had lower daytime PaO2 (60.8 +/- 7.6 vs. 76.2 +/- 9.4 mmHg; p less than 0.001), higher daytime PaCO2 (44.8 +/- 4.2 vs. 38.0 +/- 4.0 mmHg; p less than 0.001), lower forced vital capacity (FVC) and forced expiratory volume (FEV1) (p less than 0.001), but the severity of OSAS was not different whether PH was present or not (apnoea index: 62 +/- 34 hour in the PH group vs. 65 +/- 40 hour, apnoea + hypopnoea index 102 +/- 33 hour in the PH group vs. 86 +/- 36 hour, lowest sleep SaO2: 59 +/- 21% in the PH group vs. 66 +/- 18%). There were significant correlations between Ppa and: daytime PaO2 (r = -0.61; p less than 0.001), PaCO2 (r = 0.55; p less than 0.001), FEV1 (r = -0.52; p less than 0.001) but not between Ppa and apnoea index, apnoea + hypopnoea index, lowest sleep SaO2. PH and daytime hypoxaemia were associated either with chronic airway obstruction or with severe obesity.

Adult↗
PubMed1990

[Changes in sleep and night respiration in asthma and obstructive or restrictive lung diseases].

Interactions between sleep and respiration have been noticed in several lung diseases. In COPD (chronic obstructive pulmonary disease) patients, the night sleep is delayed or shortened and deep sleep is often reduced or even absent. These disturbances are associated with hypoxaemic episodes occurring either in light slow wave sleep or in REM sleep, the former being short in duration and mild but repetitive and related to ventilatory changes, the latter prolonged, often severe, and resulting from both decrease in ventilation and alterations of ventilation-perfusion ratios. Restrictive syndrome due to interstitial pneumonia, kyphoscoliosis, neuromuscular diseases or, more commonly, to obesity or even pregnancy also alter sleep in a non-specific manner. Most of them result in hypoxia during paradoxical sleep. Unquestionably, there exists a relationship between sleep and asthma (aggravation of dyspnoea at night, reduction of peak expiratory flow when awaking, stage 2 asthmatic attacks). This relationship is probably caused by multifactorial interactions.

Female↗