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Biomedical subjects

D Patton

Publications and source records attributed to D Patton.

At least 19 recordsLinked to original sources
PubMed2000

Ultrastructure of the reproductive system of the black swamp snake (Seminatrix pygaea). II. Annual oviducal cycle.

This article is the first ultrastructural study on the annual oviducal cycle in a snake. The ultrastructure of the oviduct was studied in 21 females of the viviparous natricine snake Seminatrix pygaea. Specimens were collected and sacrificed in March, May, June, July, and October from one locale in South Carolina during 1998-1999. The sample included individuals: 1) in an inactive reproductive condition, 2) mated but prior to ovulation, and 3) from early and late periods of gravidity. The oviduct possesses four distinct regions from cranial to caudal: the anterior infundibulum, the posterior infundibulum containing sperm storage tubules (SSTs), the uterus, and the vagina. The epithelium is simple throughout the oviduct and invaginations of the lining form tubular glands in all regions except the anterior infundibulum and the posterior vagina. The tubular glands are not alveolar, as reported in some other snakes, and simply represent a continuation of the oviducal lining with no additional specializations. The anterior infundibulum and vagina show the least amount of variation in relation to season or reproductive condition. In these regions, the epithelium is irregular, varying from squamous to columnar, and cells with elongate cilia alternate with secretory cells. The secretory product of the infundibulum consists largely of lipids, whereas a glycoprotein predominates in the vagina; however, both products are found in these regions and elsewhere in the oviduct. In the SST area and the anterior vagina, tubular glands are compound as well as simple. The epithelium of the SST is most active after mating, and glycoprotein vacuoles and lipid droplets are equally abundant. When present, sperm form tangled masses in the oviducal lumen and glands of the SST area. The glands of the uterus are always simple. During sperm migration, a carrier matrix composed of sloughed epithelial cells, a glycoprotein colloid, lipids, and membranous structures surround sperm in the posterior uterus. During gravidity, tubular glands, cilia, and secretory products diminish with increasing development of the fetus, and numerous capillaries abut the basal lamina of the attenuated epithelial lining of the uterus.

Animals↗
PubMed2000

The TITAN5 gene of Arabidopsis encodes a protein related to the ADP ribosylation factor family of GTP binding proteins.

The titan (ttn) mutants of Arabidopsis exhibit dramatic alterations in mitosis and cell cycle control during seed development. Endosperm development in these mutants is characterized by the formation of giant polyploid nuclei with enlarged nucleoli. Embryo development is accompanied by significant cell enlargement in some mutants (ttn1 and ttn5) but not others (ttn2 and ttn3). We describe here the molecular cloning of TTN5 using a T-DNA-tagged allele. A second allele with a similar phenotype contains a nonsense mutation in the same coding region. The predicted protein is related to ADP ribosylation factors (ARFs), members of the RAS family of small GTP binding proteins that regulate various cellular functions in eukaryotes. TTN5 is most closely related in sequence to the ARL2 class of ARF-like proteins isolated from humans, rats, and mice. Although the cellular functions of ARL proteins remain unclear, the ttn5 phenotype is consistent with the known roles of ARFs in the regulation of intracellular vesicle transport.

ADP-Ribosylation Factors↗
PubMed2000

Severe Kawasaki disease in infants: two fatal cases.

Kawasaki disease is a systemic vasculitis that manifests itself in many ways. Infants may present as atypical cases and commonly experience severe inflammatory changes. The two cases that are presented here highlight unusual severity and pathology. Patient 1 was a three-month-old infant with atypical Kawasaki disease who developed gangrenous lesions, and coronary and extracoronary artery aneurysms. Multiorgan failure ensued with diffuse cardiac and extracardiac aneurysms and thromboses at autopsy. Patient 2 was a five-month-old infant with Kawasaki disease, cholangitis and peripheral gangrene. Severe coronary artery aneurysms developed and he died following a myocardial infarction, despite multiple doses of intravenous immunoglobulin, acetylsalicylic acid (ASA) and corticosteroids. There is a higher occurrence of atypical disease and more severe vasculitis in infants with Kawasaki disease. Pathological changes are described, including coronary and extracardiac lesions. Patient 1 shows extensive peripheral gangrene and widespread aneurysms, and patient 2 illustrates severe cardiac complications with diffuse organ inflammation. Therapies including intravenous immunoglobulin, ASA, corticosteroids and antithrombotics are reviewed.

Aneurysm↗
PubMed1999

Needs-based planning for generalist physicians.

OBJECTIVES: The Manitoba Centre for Health Policy and Evaluation (MCHPE) collaborated with a provincially-appointed Physician Resource Committee in an assessment of provincial physician resources. RESEARCH DESIGN: Beginning with map-based analyses of physician supply and contacts across the province, compared with the health and socioeconomic characteristics of local populations, the study moved to a needs-based, regression-based approach to physician resource planning. RESULTS: The results challenged the popular belief that Manitoba suffers from an increasing shortage of physicians. A handful of high-need, low-supply and low-use areas are identified, as is the expensive surplus of generalist physicians in Winnipeg. (Generalist physicians include general and family practitioners as well as general internists and pediatricians.) No relationship between physician supply and health characteristics of populations, or between high physician supply and low hospital use patterns were found. Given the Committee's interest in what drives high physician contact rates, analyses of visit patterns of hypertensive patients were undertaken. We found that patients who had more complex medical conditions made more contacts, but that after controlling for this and other key patient characteristics, the patient's primary care physician's patient recall rate was a strong influence on how frequently visits were made.

Adolescent↗
PubMed1999

Determination of systolic blood pressure via pulse oximeter in transported pediatric patients.

OBJECTIVE: To compare pulse oximetry waveform systolic blood pressure measurements (POWSBP) to measurements obtained by noninvasive blood pressure measurement (NIBPM) during the transport of children. DESIGN: A prospective, convenience sample. SETTING AND PARTICIPANTS: All patients transported by a dedicated Pediatric Critical Care Transport Team were eligible for inclusion. Senior transport nurses with over 3 years of transport experience who had been instructed by the principal investigator (PI) in the technique, obtained the measurements and recorded the results. A convenience sample was obtained based on the presence or absence of one of the senior nurses on the transport team. METHODS: Measurements of blood pressure were obtained by POWSBP and NIBPM (PROPAQ@; Protocol Systems, Beaverton, OR) on pediatric patients during transport in moving ambulances or fixed wing aircraft. Measurement of systolic blood pressure by pulse oximetry (POWSBP) was obtained on all patients by observing the return of the plethysmographic waveform of the pulse oximeter as the blood pressure cuff deflated. The patients were divided into two groups; in group A POWSBP measurements were obtained by using the automated BP cuff from the PROPAQ@ and in group B by a manual BP cuff. These measurements were compared to NIBPM readings obtained at the same time. Between 3 and 13 paired readings were obtained for each patient. The actual transport time determined the number of measurements obtained. RESULTS: A total of 24 patients were enrolled in the study. Multiple matched pair readings (both POWSBP and NIBPM) were obtained from each patient for a total of 180 data points. A two variable linear regression model was run which identified a significant correlation between POWSBP and NIBPM. Group A, r = 0.7592 and r = 0.9477 for group B significant at P< 0.000001. Further, a corrective equation was developed for use with an automated BP cuff. CONCLUSIONS: The use of pulse oximetry waveform systolic blood pressure measurement is a quick and easy method with which to obtain systolic blood pressure in children during transport and shows a close correlation to the standard noninvasive blood pressure measurement. If an automated blood pressure cuff is used, then a corrective equation [NIBP-S = 41.686 + 0.7377(POBPS)] is required. Further validation in a larger group of patients is recommended.

Adolescent↗
PubMed1997

Managed care in the United States.

Medical care in the United States continues to consume an increasing amount of the Gross Domestic Product. To control the rising costs of health care many industries have turned to a controlled form of financing and delivery of health care--often referred to as managed care. Many types of managed care exist, including preferred provider organizations (PPO), exclusive provider organization (EPO), and health maintenance organizations (HMO). HMOs involve prepaid premiums, limited panels of providers and assumption of financial risk on the part of the providers. A variety of HMOs are currently operating in the United States. Managed care involves taking risks by those who administer it. Some methods of controlling patient and physician behaviour by taking risks are capitation, risk pools and withholds. With capitation the physician is paid a 'per member per month' fee regardless of whether the patient uses the service. Risk pools are concerned with who shares the risk; for example, the primary physician shares the financial risk with specialists. Withholds involve a fee-for-service with a portion withheld which may be returned to the provider if he/she is parsimonious. A concern expressed about HMOs is the possibility of restricted services. Moreover, hospital expenses make up a large portion of the total health care dollar. In 1995 the average length of stay for a Medicare patient was 6.1 days as opposed to 3.9 days for the non-Medicare patient. Indeed, HMOs were the leaders in the development of same-day surgery and out-patient treatment. Increasingly, in the United States, public and social insurance plans are turning to managed care as a method to control health care expenditure. Some government insurance plans, such as Medicare and Medicaid, also increasingly offer managed health options. The trend, for now, in the United States increases enrollment in managed care plans. Although this is occurring at a rapid pace, managed care will probably not be the final solution to provision of medical care in the United States.

Cost Control↗
PubMed1996

Influence of angioscopic vein graft preparation on development of neointimal hyperplasia in an organ culture model of human saphenous vein.

PURPOSE: Angioscopy for in situ vein graft preparation has been criticized on the basis that the trauma of instrumentation may predispose to accelerated intimal hyperplasia, jeopardizing patency rates following infrainguinal revascularization. The aim of this study was to assess the effects of angioscopic preparation on endothelial integrity and smooth muscle cell (SMC) behavior in an established organ culture model of human saphenous vein (HSV). METHODS: HSV was harvested from 12 patients during bypass surgery before and after angioscopic preparation. Endothelial integrity was evaluated by immunohistochemical staining with JC-70 and scanning electron microscopy (SEM); remaining segments of pre- and postangioscopy vein were maintained in culture for 14 days in medium supplemented with 30% fetal calf serum. Viability was confirmed by measurement of tissue adenosine triphosphate on day 14 and thickness of the neointima was measured by computerized image analysis of histologic sections. Monoclonal antibodies to proliferating cell nuclear antigen (PCNA) were used as an immunohistochemical marker for proliferating SMCs. RESULTS: There was a significant reduction in the percentage staining by JC-70 (71.3% versus 20.4%) in pre- versus postangioscopy vein (p = 0.002 by Wilcoxon's rank test; n = 12). This was supported by SEM images. Despite this, there were no significant differences between the pre- and postangioscopy HSVs after 14 days of culture with respect to neointimal thickness (61 versus 56 microns) and staining with PCNA (4.80 versus 4.08 nuclei per 10 microns), all according to Wilcoxon's rank test. CONCLUSIONS: Angioscopic vein graft preparation is associated with endothelial cell loss but does not induce additional neointimal hyperplasia in HSV in vitro. These results suggest that angioscopic manipulation does not alter SMC behavior.

Adenosine Triphosphate↗
PubMed1995

Evidence for cross-pathway regulation of metabolic gene expression in plants.

In Arabidopsis thaliana, blocking histidine biosynthesis with a specific inhibitor of imidazoleglycerol-phosphate dehydratase caused increased expression of eight genes involved in the biosynthesis of aromatic amino acids, histidine, lysine, and purines. A decrease in expression of glutamine synthetase was also observed. Addition of histidine eliminated the gene-regulating effects of the inhibitor, demonstrating that the changes in gene expression resulted from histidine-pathway blockage. These results show that plants are capable of cross-pathway metabolic regulation.

Arabidopsis↗
PubMed1995

Sexual abstinence counseling of adolescents by physicians.

Attending physicians and residents at a southeastern rural teaching hospital specializing in family practice and pediatrics, as well as local family practice physicians and pediatricians, were surveyed with regard to their counseling of adolescents about sexuality, including abstinence. The physicians were asked to complete an original 67-item questionnaire describing their attitudes and practices. More than 60% of physicians reported regularly addressing the issues of HIV, STD, pregnancy prevention, and responsible sexual behaviors. About 35% of the physicians reported regularly counseling adolescents regarding 17 other issues pertaining to pregnancy and disease prevention, sexual abuse, or related medical aspects of sexuality. No respondents felt "very effective" in their counseling. Some agree they would be helped by additional training.

Adolescent↗
PubMed1994

The relative performance of diverse measures of alcohol abuse and dependence in a community sample.

There is broad diversity among the ways in which alcohol abuse and/or dependence are defined and operationalized by researchers. In a community survey of 1,257 adult males and females, eight different measures of alcohol abuse or dependence were used. For analysis, each measure was dichotomized at its usual cutoff point. A factor analysis of distance scores between pairs of measures gave only one interpretable factor representing drinking patterns and social problems. Sensitivity and specificity were calculated for each measure with respect to abuse or dependence, as measured by the DIS-III-R. High maximum levels of drinking and social problems were moderately sensitive and specific to DIS-III-R. These relationships varied, though, for subgroups of age and gender. DSM-III-R alcohol abuse and dependence are widely respected variables but relatively expensive to measure. Alternative approaches for various survey purposes are discussed. Measures to be regarded as alternatives to the DIS-III-R are found to perform better in that role in samples limited by age and gender.

Adolescent↗
PubMed1994

The reliability and construct validity of two measures of addictive personality.

Gossop and Eysenck developed a subscale of the EPQ that discriminates between drug addicts in treatment and nonaddicts. They called this scale the Addiction Scale (AS). Previously, MacAndrew developed an Alcoholism Scale (MAC) by comparing alcoholics and nonalcoholic psychiatric patients' responses on the MMPI. In the present report both scales were completed by 615 men and 642 women as part of the Winnipeg Health and Drinking Survey, a longitudinal study of personality and health. The reliability of both scales is quite low, .64 for the AS and .57 for the MAC. Correlations with other personality measures indicate that the MAC is more associated with extraversion-related characteristics whereas the AS is more associated with neuroticism-related factors. The AS was not associated with the level of smoking, and the MAC was correlated with smoking for men only. Both scales were significantly correlated with various drinking measures, and the correlations were slightly higher for the MAC.

Adult↗
PubMed1992

Experiences and attitudes about faith healing among family physicians.

BACKGROUND: Recent media attention has focused on patients who use faith healers to care for their medical problems. Many people who use faith healers also consult physicians. This study was done to learn more about how often physicians see patients who are involved in faith healing, and to learn more about physicians' attitudes about, and experiences with, faith healing. METHODS: A 1-page questionnaire was mailed to 1025 family physicians in seven states; 594 participated, for a response rate of 59%. RESULTS: Approximately one half (52%) of the physicians were aware of at least one patient in their practice who had had a faith-healing experience. Most physicians came in contact with such patients no more frequently than once a year. Fifty-five percent agreed and 20% disagreed that reliance on faith healers often leads to serious medical problems. However, 44% thought that physicians and faith healers can work together to cure some patients, and 23% believed that faith healers divinely heal some people whom physicians cannot help. CONCLUSIONS: These results suggest that family physicians are infrequently aware of faith-healing beliefs and experiences among their patients. Family physicians were divided in their views about faith healing, with a majority expressing skepticism about faith healing and a sizeable minority favorable toward it.

Adult↗
PubMed1991

Criterion validity of two methods of evaluating marital relationships.

A structured interview and a self-report questionnaire designed to measure the quality and quantity of marital intimacy are examined by evaluating their relationship to a measure of marital adjustment. Conceptual and methodological questions regarding different techniques that measure marital quality are presented. The study suggests both techniques have established criterion validity. Advantages and disadvantages of both methods are discussed, and suggestion for future research are made.

Adaptation, Psychological↗
PubMed1991

Toxicity equivalency factors for PCBs?

In December 1990 the U.S. Environmental Protection Agency sponsored a workshop to discuss the applicability of an interim "toxicity equivalency factor" (TEF) approach to assessing risks posed by exposures to complex mixtures of polychlorinated biphenyls (PCBs). The group concluded that application of the TEF approach to PCBs would be less straightforward than it was in the case of chlorinated dibenzo-p-dioxins and dibenzofurans (CDDs/CDFs). It appears that "dioxin"-like properties of some PCB congeners are amenable to a TEF treatment that is compatible with that used for CDDs/CDFs. Such a scheme also seems to have utility in assessing risks to wildlife. Other non-"dioxin"-like toxic endpoints (e.g., neurotoxicity) appear to have a different structure-activity-related mechanism-of-action that requires a separate TEF scheme. The workshop identified data gaps in toxicology and analytical chemistry that hinder adoption of proposed TEF schemes for PCBs at this time.

Benzofurans↗
PubMed1990

Standardized portrait photography for dental patients.

Photography is becoming an increasingly important tool in the dental profession. But documentation of orthodontic or orthognathic treatment with pretreatment and posttreatment photographs can be misleading if features on one or both photographs are distorted. The dental photographer must be constantly aware of the importance of standardizing photographic variables when documentation of change is important. Although total reproducibility may not be practical, the photographer can establish a reasonably standardized approach to photographing patients. In this article the authors present the major considerations for frontal and profile facial photographs. Lens selection, camera position, subject distance, and position are all variables to be understood and controlled if accurate reproduction is desired. Numerous frontal and lateral photographs were made with head position, camera position, jaw position, and lens focal length changed to allow assessment of their contribution to the final picture. Using easily recognized facial landmarks, dental photographers can standardize frontal and lateral portraits for more consistent comparison.

Dental Records↗
PubMed1990

Evaluation of a new method for verifying truth of diagnosis in clinical research.

Having a good methodology for establishing truth of diagnosis would be invaluable to researchers in radiology. A protocol to verify the truth of diagnosis of clinical images to be used in radiologic research has been proposed that specifies six classes, depending on how the diagnosis is verified. In this paper it was evaluated. The protocol was applied to sixty-nine liver-spleen scans. Using five of the possible six classes of the protocol, 42% of the scans were verifiable. Twenty-eight per cent of the cases could be verified by non-physicians using the first four classes of the protocol. In 96% of a sample of these cases, their diagnosis matched that of the physicians. Radiologists are needed for the last two classes. However, using three radiologists to investigate Class V protocol procedures only eight (16%) more cases were clearly classifiable. Class VI was not investigated. The protocol met its objectives of reducing physician involvement and developing a detailed methodology. The difficulties inherent in verification of diagnosis are also discussed, and suggestions for improving the protocol are proposed.

Diagnosis↗