Biomedical subjects

C A Doyle

Publications and source records attributed to C A Doyle.

11 recordsLinked to original sources

PubMed1994

Relationships between spinocervical tract neurons and descending catecholamine-containing axons in the cat.

Lumbosacral (L6-S1) spinal cord neurons in the cat were retrogradely labelled after uptake of horseradish peroxidase by their severed axons in the upper cervical (C3-C4) dorsolateral funiculus. Sections of L6-S1 containing labelled neurons were then processed immunocytochemically using antibodies against dopamine-beta-hydroxylase or tyrosine hydroxylase, two enzymes responsible for the synthesis of catecholamines. Two hundred and ninety eight retrogradely-labelled cells within laminae III-V of the dorsal horn were examined under high power (x 1000) with the light microscope. In Triton X-100-treated material, only 13% of these cells had catecholamine-containing varicosities closely apposed to their somata and proximal dendrites, which suggests that in comparison with the postsynaptic dorsal column pathway, spinocervical tract neurons are only sparsely innervated by descending catecholaminergic axons.

Animals↗

PubMed1992

Development of fibroblast-type-II cell communications in fetal rabbit lung organ culture.

The development of the fetal lung is regulated by fibroblast-type-II cell communications which involve fibroblast pneumonocyte factor (FPF). FPF production is positively regulated by glucocorticoids and negatively regulated by dihydrotestosterone (DHT) and transforming growth-factor beta (TGF-beta). We studied whether DHT or TGF-beta affected other steps in the process of lung maturation, by studying how the developing lung in organ culture would respond to exogenously supplied FPF after DHT or TGF-beta exposure. Fetal rabbit (day 19 of gestation) lung organ cultures were prepared and cultured in the presence of cortisol, DHT or TGF-beta. After seven days, the media were replaced with serum-free medium containing either cortisol or FPF conditioned medium. The incorporation of [14C]glycerol into surfactant lamellar body DSPC was studied over 24 h as the index of surfactant synthesis. Results were compared to simultaneous control cultures. Treatment had no significant effect on tissue protein concentration or on the efficiency of lamellar body recovery. Cortisol stimulated baseline incorporation of glycerol into DSPC. This was inhibited by DHT, such that DHT plus cortisol treatment was no different from untreated controls. FPF stimulated the incorporation of glycerol into DSPC, and did so even after culture treatment with DHT. Cultures treated with TGF-beta exhibited glycerol incorporation similar to untreated controls. After TGF-beta exposure, FPF did not stimulate glycerol incorporation into DSPC. We conclude that DHT interferes with progression of lung development by delaying the appearance of FPF production by the fibroblast. TGF-beta, on the other hand, inhibits other elements of lung maturation besides FPF production. We speculate that TGF-beta interferes with type-II cell development such that the cell cannot respond to FPF.

Animals↗

PubMed1992

Safety profile of cefprozil.

The clinical and laboratory safety of cefprozil was analyzed with data from 4,227 patients who received the drug in North American and European clinical efficacy trials. Of these patients, 3,016 adults and children received capsules or tablets, while 1,211 patients (mostly children) were treated with cefprozil suspension. Cefprozil was used in single-daily or twice-daily dosing regimens for treatment of infections of the upper and lower respiratory tracts, sinuses, middle ear, urinary tract, and skin and skin structure. The incidence of adverse clinical events and laboratory abnormalities was similar to that associated with use of other oral cephalosporins. Gastrointestinal adverse effects were the predominant adverse clinical event, although the incidence of diarrhea with cefprozil was much lower than that with cephalosporins that are less well absorbed. The data confirm the safety of cefprozil in both adult and pediatric patients.

Cephalosporins↗

PubMed1991

Ultrastructural analysis of noradrenergic nerve terminals in the cat lumbosacral spinal dorsal horn: a dopamine-beta-hydroxylase immunocytochemical study.

Noradrenaline-containing nerve terminals within the cat spinal dorsal horn were studied by immunocytochemical localization of dopamine-beta-hydroxylase. Immunoreactive terminals formed symmetrical (Gray type II) synaptic specializations with dendrites and somata throughout laminae I-IV, but no junctions were formed with other axons. These findings suggest that noradrenaline regulates sensory transmission through the dorsal horn via a postsynaptic action.

Animals↗

PubMed1991

Catecholaminergic innervation of the spinal dorsal horn: a correlated light and electron microscopic analysis of tyrosine hydroxylase-immunoreactive fibres in the cat.

The ultrastructural organization of presumed catecholamine-containing boutons, in the dorsal horn of the cat lumbosacral spinal cord, was examined in an immunocytochemical study using an antiserum against tyrosine hydroxylase. The study was restricted to the first four laminae of Rexed. Light microscopic inspection revealed numerous, varicose, tyrosine hydroxylase-immunoreactive axons throughout this region of the spinal cord. Within laminae I and II the fibres exhibited a prominent rostrocaudal orientation, while in laminae III and IV they were organized predominantly dorsoventrally. Correlated ultrastructural analysis confirmed that these varicosities were synaptic boutons. Forty-five of these structures were examined through serial sections and they were found to form symmetrical (Gray type II) synaptic junctions with dendrites (95%) and somata (5%). Immunoreactive boutons were not observed to be either presynaptic or postsynaptic to axon terminals. These findings suggest that catecholamines within the spinal dorsal horn act through a postsynaptic action upon dorsal horn neurons.

Afferent Pathways↗

PubMed1990

Assessing the institutional choice process of student-athletes.

The primary purpose of this investigation was to determine the relative importance of the attributes that student-athletes use when determining their choice of a university. A second purpose was to compare previous athletic institutional choice studies with the results of this study to determine if the most important attributes were similar and to compare and contrast methodologies. Six hundred five Division I student-athletes (344 baseball players and 261 softball players) from all eight national geographic regions of the NCAA participated in this study. The experimental procedure was based on Information Integration Theory and a 2(10) fractional factorial design that resulted in 32 "choice sets." These choice sets were composed of universities described by 10 attributes. This framework required that the student-athletes choose from among three university profiles, thereby realistically simulating the decision process. The results for the aggregate sample show that the "Amount of Scholarship" attribute was the most important factor in the institutional choice process. Many demographic variables were analyzed (sex, race, amount of scholarship received as a freshman, amount of perceived financial need, self-reported grade-point average, questionnaire completion procedures, in-state/out-of-state status, NCAA region, and rank in high school) in conjunction with the choice set data in a post-hoc framework. The results for a subset of these variables are reported in this paper; differences (in the order of importance of the attributes) were found among groups. A primary finding of this study is that a student-athlete's perceived financial need has a critical impact on the institutional choice process.(ABSTRACT TRUNCATED AT 250 WORDS)

Choice Behavior↗

PubMed1984

A prospective study of asthma in a rural community.

Changes in symptoms and pulmonary function among asthmatic subjects in the general population remain poorly characterized. We studied 1,303 white residents aged seven years and older in Lebanon, Conn, a rural community largely unaffected by air pollution or major occupational exposures. These residents were examined in 1972 and again in 1978. There were 73 asthmatic subjects seen in 1972 who were followed. In addition, we identified 278 persons in 1972 who complained of wheezing who were also seen in 1978. Of the original asthmatic subjects, 50 (68 percent) were in remission; and from the original nonasthmatic population, 19 (1.4 percent) new asthmatic subjects were identified. Similarly, the condition of 215 (77 percent) of those who initially complained of wheeze had improved, whereas 56 (4.6 percent) of those initially studied either developed new wheeze or saw their wheezing worsen. When the groups of persons complaining of wheeze and the asthmatic subjects were analyzed for the presence of chronic bronchitis, we found a significant correlation between wheeze and chronic bronchitis in individuals aged 18 years and older (p less than 0.001) for both men and women, and a significant correlation (p less than 0.001) between asthma and chronic bronchitis in women aged 18 years and older. Loss of pulmonary function over time measured in terms of the forced expiratory volume in one second and the forced expiratory flow at 50 percent of total lung capacity was consistently greater for asthmatic adults than for nonasthmatic adults. Furthermore, when individuals were studied by the severity and duration of their asthmatic symptoms, a trend of worse pulmonary function was seen in those individuals with chronic asthma. We conclude that remission rates among asthmatic subjects and persons with wheeze are high in individuals aged seven years and older, that chronic bronchitis is frequently associated with wheezing and a history of asthma in adults, and that significant abnormalities in pulmonary function as well as accelerated loss of pulmonary function are associated with asthma.

Adolescent↗

PubMed1982

A longitudinal study of respiratory health in a rural community.

We studied the white residents of Lebanon, Connecticut, a rural community, cross-sectionally in 1972 and a follow-up survey in 1978. In this community, we examined prospectively the growth and decay of lung function and the prevalence, attack, and remission of respiratory symptoms in 1,262 persons. These longitudinal findings were related to sex, age, and smoking habits. Respiratory symptoms and 3 lung function variables were examined: forced expiratory volume in one second (FEV1) and maximal expiratory flow rates at 50 and 25% of vital capacity (Vmax50 and Vmax25). The representativeness of the follow-up population was examined by an extensive analysis of the respondents and nonrespondents based on their cross-sectional characteristics. These analyses did not, in general, reveal any consistent results indicating that a healthier population was followed. The longitudinal data showed that lung growth continued into early adulthood (25 to 34 yr of age) with a leveling off and decline beginning at 35 yr and older. This is in contrast to cross-sectional studies of growth and decay of lung function, which show less growth among the young and more decay among adults. The rates of growth in both males and females were affected by their smoking status, with smokers having less growth and greater decline than nonsmokers. In particular, lung function growth was impaired in young smokers as early as 15 to 24 yr of age, and an actual decline was seen in the females of this age group.

Adolescent↗

PubMed1981

Smoking and lung function.

In a cross-sectional survey of 3 separate communities, we studied the white residents 7 year of age and older in order to determine the relation between cigarette smoking and lung function. We identified 2,817 nonsmokers, 664 ex-smokers, and 1,209 smokers who were further classified as light smokers (1 to 20 cigarettes per day) and heavy smokers (greater than 20 cigarettes per day). Residual lung function (observed-predicted) was examined in these groups for forced expiratory volume in one second (rFEV1) and for maximal expiratory flow rates at 50% and 25% of the vital capacity (rVmax50% and rVmax 25%). Mean residuals by sex, age, and smoking category were compared and revealed an increasing progression of lung function loss with advancing age in males and females in all smoking categories. These age-related trends were due primarily to the amount smoked by persons in each group. The age of onset of these abnormalities was found to be as early as the age group 15 to 24 yr. Abnormalities were greater in smokers than ex-smokers, even when the amount smoked was taken into account. This is suggested improvement in lung function after cessation of smoking. Men and women were found to experience the same relative degree of gain. Also, the contribution of the various smoking habits to lung function loss was assessed using regression analyses and accounted for no more than 15% of the variation of the residual lung function. Combinations of variables were found to explain only slightly more variation than a single variable. The two most important variables were duration of smoking and pack-years. Inhalation and use of filters were not significant. Although the same amount of variation explained by the smoking variables after accounting for age, height, weight, and sex was small, this variation accounted for almost all of the decrease, over age, in residual lung function for smokers and ex-smokers.

Adolescent↗

PubMedDate not supplied

Cefprozil versus cefaclor in the treatment of acute and uncomplicated urinary tract infections. Cefprozil Multicenter Study Group.

Cefprozil is a new oral cephalosporin with an in vitro spectrum of activity that includes the pathogens most commonly associated with acute and uncomplicated urinary tract infections (UTIs). A multicenter, randomized study was conducted to compare the clinical efficacy and safety of cefprozil, administered once daily, with cefaclor, administered three times a day, for ten days in patients 2 years of age or older who had acute and uncomplicated UTIs. The rate of satisfactory clinical response in evaluable patients was 87% in the cefprozil group and 84% in the cefaclor group. The patient bacteriologic response rates were also similar: 83% for cefprozil and 85% for cefaclor. The overall effective response rate for both cefprozil and cefaclor was 77%. Both drugs were well tolerated, with no difference in the incidence of drug-related adverse events. Because of its efficacy and once-daily dosing regimen, cefprozil may be an alternative to currently available oral antibiotics in the treatment of UTIs.

Acute Disease↗

PubMedDate not supplied

Cefprozil versus cefaclor in the treatment of mild to moderate skin and skin-structure infections. The Cefprozil Multicenter Study Group.

In a multicenter study, 598 patients with skin or skin-structure infections were randomly assigned to receive 500 mg of cefprozil once daily (or 20 mg/kg once daily) or 250 mg of cefaclor three times daily (or 20 mg/kg daily in three equal doses) for 5 to 10 days. Treatment was evaluated in 212 cefprozil-treated patients and in 210 cefaclor-treated patients. The patients were aged 2 to 99 years (mean, 28 years) and their primary diagnoses were impetigo (in 99 patients), pyoderma (in 98), superficial abscess (in 70), and cellulitis (in 64). A satisfactory clinical response was found in 93% of the cefprozil-treated patients and in 92% of the cefaclor-treated patients, the pathogens were eradicated in 91% and 89%, and overall treatment was rated effective in 87% of both groups. Adverse clinical events were reported by 5% of the patients in both groups; one cefprozil-treated patient and three cefaclor-treated patients withdrew from treatment because of adverse events. It is concluded that cefprozil administered once daily is as effective and safe as cefaclor administered three times daily in the treatment of mild to moderate skin and skin-structure infections.

Abscess↗