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Biomedical subjects

J Purdy

Publications and source records attributed to J Purdy.

16 recordsLinked to original sources
PubMed1999

An autosomal genomic screen for autism. Collaborative linkage study of autism.

Autism is a severe neurodevelopmental disorder defined by social and communication deficits and ritualistic-repetitive behaviors that are detectable in early childhood. The etiology of idiopathic autism is strongly genetic, and oligogenic transmission is likely. The first stage of a two-stage genomic screen for autism was carried out by the Collaborative Linkage Study of Autism on individuals affected with autism from 75 families ascertained through an affected sib-pair. The strongest multipoint results were for regions on chromosomes 13 and 7. The highest maximum multipoint heterogeneity LOD (MMLS/het) score is 3.0 at D13S800 (approximately 55 cM from the telomere) under the recessive model, with an estimated 35% of families linked to this locus. The next highest peak is an MMLS/het score of 2.3 at 19 cM, between D13S217 and D13S1229. Our third highest MMLS/het score of 2.2 is on chromosome 7 and is consistent with the International Molecular Genetic Study of Autism Consortium report of a possible susceptibility locus somewhere within 7q31-33. These regions and others will be followed up in the second stage of our study by typing additional markers in both the original and a second set of identically ascertained autism families, which are currently being collected. By comparing results across a number of studies, we expect to be able to narrow our search for autism susceptibility genes to a small number of genomic regions. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 88:609-615, 1999.

Adolescent↗
PubMed1999

The PEP transducer: a new way of measuring respiratory rate in the non-intubated patient.

OBJECTIVES: To explore the use of a pyroelectric polymer (PEP) film as a transducer for a simple respiratory rate monitor and to evaluate the transducer in a laboratory situation. METHODS: Laboratory evaluation of a new pyroelectric transducer for measurement of respiratory rate. RESULTS: The amplified output from the pyroelectric film produced an excellent respiratory trace when used on a normal spontaneously breathing subject. The transducer is cheap, robust, and reliable. CONCLUSIONS: PEP films have the potential to be used as cheap and effective transducers in respiratory rate monitors for non-intubated patients. In the laboratory, they have many desirable characteristics which should now be evaluated in a clinical setting.

Evaluation Studies as Topic↗
PubMed1995

The cumulative verification image analysis tool for offline evaluation of portal images.

PURPOSE: Daily portal images acquired using electronic portal imaging devices contain important information about the setup variation of the individual patient. The data can be used to evaluate the treatment and to derive correction for the individual patient. The large volume of images also require software tools for efficient analysis. This article describes the approach of cumulative verification image analysis (CVIA) specifically designed as an offline tool to extract quantitative information from daily portal images. METHODS AND MATERIALS: The user interface, image and graphics display, and algorithms of the CVIA tool have been implemented in ANSCI C using the X Window graphics standards. The tool consists of three major components: (a) definition of treatment geometry and anatomical information; (b) registration of portal images with a reference image to determine setup variation; and (c) quantitative analysis of all setup variation measurements. The CVIA tool is not automated. User interaction is required and preferred. Successful alignment of anatomies on portal images at present remains mostly dependent on clinical judgment. Predefined templates of block shapes and anatomies are used for image registration to enhance efficiency, taking advantage of the fact that much of the tool's operation is repeated in the analysis of daily portal images. RESULTS: The CVIA tool is portable and has been implemented on workstations with different operating systems. Analysis of 20 sequential daily portal images can be completed in less than 1 h. The temporal information is used to characterize setup variation in terms of its systematic, random and time-dependent components. The cumulative information is used to derive block overlap isofrequency distributions (BOIDs), which quantify the effective coverage of the prescribed treatment area throughout the course of treatment. Finally, a set of software utilities is available to facilitate feedback of the information for treatment plan recalculation and to test various decision strategies for treatment adjustment. CONCLUSIONS: The CVIA tool provides comprehensive analysis of daily images acquired with electronic portal imaging devices. Its offline approach allows characterization of the nature of setup variation for the individual patient that would have been difficult to deduce using only a few daily or weekly portal images. Distribution of the tool will help establish an important database of setup variation from many clinics. The information derived from CVIA can also serve as the foundation to integrate treatment verification, treatment planning, and treatment delivery.

Computer Peripherals↗
PubMed1995

Preservation of auditory and vestibular function after surgical removal of bilateral vestibular schwannomas in a patient with neurofibromatosis type 2.

The outcome of acoustic neuroma (vestibular schwannoma) surgery continues to improve rapidly. Advances can be attributed to several fields, but the most important contributions have arisen from the identification of the genes responsible for the dominant inheritance of neurofibromatosis types 1 (NF1) and 2 (NF2) and the development of magnetic resonance imaging with gadolinium enhancement for the early anatomic confirmation of the pathognomonic, bilateral vestibular schwannomas in NF2. These advances enable early diagnosis and treatment when the tumors are small in virtually all subjects at risk for NF2. The authors suggest that advising young NF2 patients to wait until complications develop, especially hearing loss, before diagnosing and operating for bilateral eighth nerve schwannomas may not always be in the best interest of the patient. To the authors' knowledge, this is the first reported case of preservation of both auditory and vestibular function in a patient after bilateral vestibular schwannoma excision.

Adult↗
PubMed1991

Reduction in radiation exposure to nursing personnel with the use of remote afterloading brachytherapy devices.

The radiation exposure to nursing personnel from patients with brachytherapy implants on a large brachytherapy service were reviewed. Exposure to nurses, as determined by TLD monitors, indicates a 7-fold reduction in exposure after the implementation of the use of remote afterloading devices. Quarterly TLD monitor data for six quarters prior to the use of remote afterloading devices demonstrate an average projected annual dose equivalent to the nurses of 152 and 154 mrem (1.5 mSv). After the implementation of the remote afterloading devices, the quarterly TLD monitor data indicate an average dose equivalent per nurse of 23 and 19 mrem (0.2 mSv). This is an 87% reduction in exposure to nurses with the use of these devices (p less than 0.01).

Brachytherapy↗
PubMed1990

Wellness centers.

Explore the source record for details and available documents.

Ambulatory Care Facilities↗
PubMed1989

Reversal of impaired wound healing in irradiated rats by platelet-derived growth factor-BB.

This study examined the potential influence of platelet-derived growth factor-BB homodimers (PDGF-BB) on surgical incisions in irradiated animals with depressed wound healing. Rats were irradiated with either 800 rads total body or 2,500 rads surface irradiation. Parallel dorsal skin incisions were made 2 days later, and PDGF-BB was applied topically a single time to one of two incisions. In total body-irradiated rats, bone marrow-derived elements were severely depressed, wound macrophages were virtually eliminated, and PDGF-BB treatment was ineffective. However, in surface-irradiated rats, PDGF-BB treatment recruited macrophages into wounds and partially reversed impaired healing on day 7 (p less than 0.005) and day 12 (p less than 0.001). PDGF-BB-treated wounds were 50 percent stronger than the paired control wounds. The results suggest PDGF requires bone marrow-derived cells, likely wound macrophages, for activity and that it may be useful as a topical agent in postirradiation surgical incisions.

Animals↗
PubMed1985

In vitro fertilization: a treatment for male infertility.

Three-quarters of 41 women whose husbands were the cause of infertility in the couple had one or more embryos replaced after in vitro fertilization. One-third became pregnant despite their long history of infertility; the incidence of pregnancy was 45% after one or more replacements of embryos. In a group of 61 couples where both partners were infertile, 26% became pregnant. These data indicate that the lower chance of fertilization with poor semen is balanced by a higher chance of pregnancy in women with a normally functioning reproductive system. Oligospermia, asthenospermia, teratospermia, and autoimmunity are among the many forms of male infertility which can now be successfully treated by in vitro fertilization. Overall, 57% of the oocytes were fertilized, and almost 50% of men with very low numbers of active spermatozoa (less than or equal to 0.5 X 10(6)/ml motile spermatozoa) were successful in establishing pregnancy. Two semen parameters impaired fertilization most: seminal inflammatory cells and low progressive activity. The collection of split ejaculates and the careful preparation of spermatozoa, by sedimentation and layering methods, proved to be beneficial, improving sperm motility and raising the chance of fertilization.

Embryo Transfer↗
PubMed1975

Selective changes in the permeability of the blood-brain barrier after pharmacological or surgical deafferentation.

Unilateral eye removal results in an increased delivery of blood-borne glucose, norepinephrine, choline, and tyrosine, but not of proline, to the denervated optic lobes. Administration of reserpine to chicks increases penetrance of norepinephrine into the brain but not of tyrosine, choline, or proline. Selective alterations in the permeability of the blood-brain barrier may represent a mechanism for the modulation of the delivery of critical nutrients to the brain.

Animals↗