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Biomedical subjects

T R Cooper

Publications and source records attributed to T R Cooper.

At least 19 recordsLinked to original sources
PubMed2000

Rapid detection of microorganisms in blood cultures of newborn infants utilizing an automated blood culture system.

BACKGROUND: Neonatal sepsis is a low incidence, high-risk disease with many sepsis work-ups performed to detect a single case. Seventy-two hours of antibiotic therapy have been traditionally recommended pending negative culture results. Improved culture media and new technology integrated into blood culture systems could shorten incubation time required to detect positive culture results. This would then change the length of antibiotic therapy in the management of the newborn infant with suspected sepsis. In addition, previous data supporting the 72-hour recommendation were retrospectively acquired, utilized nonautomated systems, and reported in an era with a different population of microorganisms cultured in special care nurseries. OBJECTIVE: Evaluate the time of incubation to detect positive blood cultures from newborn infants with suspected sepsis using a computer-assisted, automated blood culture system, ESP (Trek Diagnostic Systems, Inc, Westlake, OH). DESIGN: Prospective, observational study. PATIENTS AND SETTING: All positive blood culture results that were obtained from term and preterm newborn infants born from November 1993 through June 1997 at a publicly funded hospital with over 6000 live births per year. METHODS: As positive blood culture results were identified, data were prospectively obtained from the patient's medical record. The computer algorithm in the automated blood culture system determined the time to positivity. Time to positivity was determined for blood cultures obtained before the initiation antimicrobial therapy and compared with those cultures obtained after beginning therapy. Time to positivity was also evaluated for clinically important Gram-positive and Gram-negative bacteria and yeast. RESULTS: Four hundred fifty-five positive blood culture results were obtained from 222 patients. Gram-positive organisms accounted for 80% (366/455) of the positive culture results, Gram-negative organisms accounted for 11% (48/455), and yeast for 9% (41/455). Virtually all cultures growing clinically significant Gram-positive and Gram-negative organisms were positive by 24 to 36 hours of incubation. Cultures growing Staphylococcus epidermidis were virtually all positive after 36 to 48 hours of incubation. Of cultures growing yeast, 88% (36/41) were positive by 48 hours of incubation. There was no difference in time to positivity in pretherapy or posttherapy obtained positive blood cultures. Prenatally administered antibiotics did not affect time to positivity in positive cultures drawn on the first day of life. In a selected group of microorganisms that are the frequent cause of bacteremia in term infants, 97% and 99% of cultures were positive by 24 to 36 hours of incubation when only pretherapy cultures are evaluated. CONCLUSIONS: The ESP blood culture system identified 77%, 89% and 94% of all microorganisms at 24, 36, and 48 hours of incubation in aerobic cultures obtained from both term and preterm infants. Introduction of antimicrobial therapy did not affect time to positivity. Reducing duration of antibiotic therapy to 24 to 36 hours should be considered in term, asymptomatic newborn infants undergoing evaluation for suspected sepsis for maternal indications. Confirmation of similar rapidity of detection using other blood culture systems should be undertaken.

Anti-Bacterial Agents↗
PubMed1999

Managing disagreements in the management of short bowel and hypoplastic left heart syndrome.

BACKGROUND AND OBJECTIVES: When innovative, not yet fully proven therapies are introduced, physicians may have neither experience nor sufficient data in the medical literature to assist in their decision to discuss them with and/or recommend them to patients. Little is known about how physicians deal with this uncertainty. Moreover, when multiple physicians caring for a single patient have reached different conclusions regarding this new therapy, the potential for disagreement exists that could give rise to ethical issues as well as cause confusion to the patient. To explore these topics, we investigated the attitudes of specialists to therapies for two life-threatening diseases: hypoplastic left heart syndrome (HLHS) and short bowel syndrome. METHODS: A forced choice questionnaire was distributed to the heads of neonatology, pediatric cardiology, and pediatric gastroenterology training programs asking about their outcome impressions and treatment recommendations and about the local availability of treatments. In addition, responses from specialists from the same institution were linked in a confidential manner to evaluate the frequency of disagreement within the same institution. Responses were analyzed using chi(2) and Wilcoxon matched pair analysis as appropriate. RESULTS: The overall rate of response was 79%. In institutions that had both neonatology and pediatric gastroenterology training programs, there was a 59% response rate compared with a 73% response rate from institutions that had both neonatology and cardiology programs. Significant differences were noted among specialists as to who would be involved in discussions of therapeutic options with patients in both HLHS and short bowel syndrome. Differences also were noted in the willingness of specialists to discuss and recommend therapies, in the perceived survival and quality of life by various specialists after transplant and palliative surgery, and in the local availability of various options. The neonatologists and gastroenterologists at the same institution disagreed on responses in 34% of the questions with only 1 of the 25 pairs in full agreement. In contrast, the neonatologists and pediatric cardiologists at the same institution disagreed in only 14% of the questions with 7 of the 28 pairs in full agreement. CONCLUSIONS: Substantial disagreement among specialists about new interventions was found. There seem to be fewer differences among specialists when dealing with the more mature therapy, HLHS. Two major ethical issues arise. First, there seems to be no accepted professional standard to which individuals can appeal when determining whether to discuss or recommend new, not-yet-fully-proven technologies. Second, there is the potential for much patient confusion when counseling physicians recommend different options. Colleagues as individuals and specialists as groups should talk to each other before individual discussions with families to ensure that there is a clear understanding of differing beliefs.

Attitude of Health Personnel↗
PubMed1998

Actuarial survival in the premature infant less than 30 weeks' gestation.

OBJECTIVE: Because survival from admission to discharge does not provide parents and physicians information about future life expectancy in the premature neonate, we characterized the actuarial survival, defined as the future life expectancy from a given postnatal age, in a large inborn population of premature infants < 30 weeks' gestation. STUDY DESIGN: We determined daily actuarial survival of 1925 inborn infants (23 to 29 weeks' gestation) admitted to the Baylor Affiliated Nurseries from July 1986 through December 1994, stratified by 100-g birth weight and by 1-week gestational-age intervals. RESULTS: In the 501- to 600-g birth weight stratum, actuarial survival improved from 31% at birth, to 61% on day of life 7, and then to 75% on day of life 28; in the 901- to 1000-g birth weight stratum, actuarial survival improved from 88%, to 94%, and then to 98% throughout the same times, respectively. Similar trends were obtained when data were stratified by gestational age. CONCLUSIONS: Survival in the smallest infants improves dramatically during the first few days of life, but there is a significant risk for late death in the smallest of these infants.

Actuarial Analysis↗
PubMed1996

Diffusion of innovative approaches to managing hypoplastic left heart syndrome.

OBJECTIVE: To study the perceptions of outcome and the diffusion into practice of innovative approaches such as palliative surgery and heart transplantation to treat hypoplastic left heart syndrome. DESIGN: A forced-choice questionnaire was sent to 108 US neonatology section heads. Responses were analyzed using Wilcoxon matched pairs, chi 2 analysis, and multivariant logistic regression. RESULTS: Ninety-three questionnaires (86%) were returned. All respondents discussed palliative surgery or transplantation or both with parents; 71 (76%) of 93 also discussed comfort care. Nineteen (24%) of 80 recommended comfort care only, 51 (64%) of 80 recommended surgery only, and 10 (12%) of 80 recommended both. Of the 61 respondents recommending one or both surgical procedures, palliative surgery was recommended by 44 and transplantation by 33. Respondents perceived that transplantation was associated with a lower 1-year mortality than palliative surgery (P < .001) and with a better quality of life (P < .001). CONCLUSIONS: Palliative surgery and transplantation are widely used to treat hypoplastic left heart syndrome. The continued availability of comfort care suggests that these surgical procedures are still in transition from experimental technology to standard of care.

Cardiac Surgical Procedures↗
PubMed1996

The association between flexibility and running economy in sub-elite male distance runners.

The purpose of this study was to examine the association between nine measures of limb and trunk flexibility and running economy. Within a week prior to running economy assessment, and after 10 min of jogging at 3.13 m.s-1, 19 well-trained male sub-elite distance runners underwent two complete sets of lower limb and trunk flexibility assessments. Runners then completed two 10-min running economy assessment sessions on consecutive days at 4.13 m.s-1 following two 30-min sessions of treadmill accommodation at 4.13 m.s-1. Intraclass correlation coefficients indicated that the repeated flexibility measurements were highly reliable (X R = 0.92 +/- 0.09), as were the two running economy appraisals (R = 0.99). Correlational analyses revealed that dorsiflexion (r = 0.65) and standing hip rotation (r = 0.53) were significantly (P < or = 0.05) associated with the mean aerobic demand of running, such that runners who were less flexible on these measures were more economical. Although speculative, these results suggest that inflexibility in certain areas of the musculoskeletal system may enhance running economy in sub-elite male runners by increasing storage and return of elastic energy and minimizing the need for muscle-stabilizing activity.

Adult↗
PubMed1992

Importance of a patent infarct-related artery for hospital and late survival after direct coronary angioplasty for acute myocardial infarction.

The importance of a patent infarct-related artery (IRA) for hospital and late survival was examined in 383 patients with acute myocardial infarction treated with direct coronary angioplasty. At hospital discharge, 317 of 348 patients (91%) had a patent IRA and mean follow-up left ventricular (LV) ejection fraction (EF) was 58%. Cardiac survival after hospital discharge at 1, 3 and 6 years was 99, 95 and 90%. Patency of the IRA was the most important determinant of hospital mortality: patent versus occluded IRA, 5 vs 39% mortality, p less than 0.001. Follow-up LVEF was the most important determinant of late cardiac mortality: follow-up LVEF greater than or equal to 45 versus less than 45%, 2 versus 24% mortality, p less than 0.001. Patency of the IRA was not a significant predictor of late cardiac mortality in the group as a whole: patent versus occluded IRA, 4.7 versus 6.5% mortality, p = 0.67. In the subgroup of patients with depressed initial LVEF less than 45%, patency was a significant predictor of late cardiac mortality: patent versus occluded IRA, 9.2 versus 40% mortality, p = 0.03. Patients with a patent IRA had better recovery of LV function than patients with an occluded IRA (follow-up LVEF 58.5 versus 47.6%, p less than 0.001). When late cardiac mortality was adjusted for differences in follow-up LVEF, patency was no longer a significant predictor of late mortality. Our results indicate patency of the IRA is the most important determinant of hospital survival, and LV function (measured after recovery) is the most important determinant of late cardiac survival.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Cell loss and class distribution of TH-I cells in the substantia nigra of the neurological mutant, weaver.

Eight-week-old homozygous weaver mutant mice and littermate wildtype controls were perfused with a buffered acrolein and paraformaldehyde solution. The brains were subsequently removed, blocked and sectioned on a vibratome. Representative sections through the midbrain were incubated overnight with an antibody for tyrosine hydroxylase. Visualization of the antibody was achieved using the peroxidase-antiperoxidase technique. The immunoreactive cells in the substantia nigra were examined to determine the subclasses of cells that are affected when dopaminergic neurons are lost in these mutants. Class distributions were determined and the data were subjected to chi 2 analyses. The results indicate a significant loss of tyrosine hydroxylase-immunoreactive cells in both the pars compacta and pars lateralis that is dependent upon the group and the region being studied. In addition, distributional shifts within the classes of labeled neurons suggest that there is an increase in the small neurons over the expected numbers in both divisions of the substantia nigra.

Animals↗
PubMed1989

An enzyme-linked immunosorbent assay for cortisol in the saliva of man and domestic farm animals.

An enzyme-linked immunosorbent assay has been developed for the direct assay of cortisol in the saliva of man, sheep, calf and pig. The assay is sensitive (integral of 1pg), highly specific and reproducible, and has the advantage over radioimmunoassay in being cheaper and quicker to carry out. The relatively-non invasive method of collecting saliva on cotton buds coupled with simple assay equipment provide a good potential for assessing cortisol status in studies on stress and welfare in farm animals as well as the possibility of monitoring cortisol status in mammals generally.

Animals↗
PubMed1987

GABAA and GABAB receptor-mediated inhibition of release of 5-hydroxytryptamine in the intermediate lobe of the rat pituitary gland.

Isolated neurointermediate lobes or neural lobes of the rat pituitary gland attached to the pituitary stalk were incubated in vitro and the spontaneous or electrically (pituitary stalk stimulation, 5 Hz, 1,500 pulses) evoked release of 5-hydroxytryptamine was determined. The evoked release of 5-hydroxytryptamine from the neurointermediate lobe was increased fivefold in the presence of the dopamine receptor antagonist (-)-sulpiride (1 microM). The evoked release of 5-hydroxytryptamine from the isolated neural lobe was not altered by (-)-sulpiride. The evoked release of 5-hydroxytryptamine from the isolated neural lobe in the presence of (-)-sulpiride was less than 5% of that from the combined neurointermediate lobe showing that most of the 5-hydroxytryptamine released from the combined neurointermediate lobe originated in the intermediate lobe. The evoked release of 5-hydroxytryptamine from the neurointermediate lobe in the presence of (-)-sulpiride showed a diurnal variation. It was three to five times higher between 9.30 and 14.00 h than between 8.30 and 9.30 h or between 14.00 and 16.00 h. The 5-hydroxytryptamine tissue content at the end of the incubation experiments also showed similar variations which were, however, less pronounced. The evoked release of 5-hydroxytryptamine from the neurointermediate lobe, in the presence of (-)-sulpiride, was reduced by the preferential GABAA receptor agonist muscimol or the selective GABAB receptor agonist (-)-baclofen in a concentration-dependent manner. Bicuculline, a selective GABAA receptor antagonist inhibited the effect of muscimol, but not that of (-)-baclofen. Bicuculline alone did not affect the release of 5-hydroxytryptamine from the gland. It is concluded that the release of 5-hydroxytryptamine in the intermediate lobe is influenced by both dopaminergic and GABAergic mechanisms.

Animals↗
PubMed1986

Uric acid is released in the zona incerta of the subthalamic region of the sheep during rumination and in response to feeding and drinking stimuli.

The technique of intracranial dialysis was used to sample changes in monoamine metabolite and uric acid concentrations in the zona incerta (ZI) of the subthalamic region of conscious sheep during rumination and in response to the presentation of feeding and drinking stimuli. Sequential 10-min dialysis samples were taken over a 5-h period with stimuli presented at hourly intervals. For each animal, sampling was carried out weekly for 2-3 months. Results from HPLC analysis showed that concentrations of uric acid rose significantly in the ZI, but not in the cortex or peripheral plasma, during rumination, eating, drinking or exposure to the sight or smell of food. No response to control stimuli--loud noise, smell of amyl acetate or sight of a syringe--was found. Concentrations of 5-hydroxyindol-3-yl-acetic acid in the ZI were unaffected.

Acoustic Stimulation↗
PubMed1986

A semi-automated fluorimetric method for measuring acetylcholinesterase activity in small volumes of cerebrospinal fluid and tissue extracts using acetylcholine as substrate.

A fluorimetric method for the assay of acetylcholinesterase (AChE; EC 3.1.1.7) in tissue extracts and cerebrospinal fluid, using acetylcholine as the substrate, is described. The method is based on the measurement of hydrogen peroxide, formed by the oxidation of choline resulting from the action of AChE on acetylcholine, by means of horseradish peroxidase and 4-hydroxy-3-methoxyphenylacetic acid (HVA) to yield a fluorescent derivative. Choline, if present in any sample to be analysed, is first removed by a modification of the peroxidase reaction during preincubation.

Acetylcholine↗
PubMed1986

Monoamines in tubero-hypophyseal structures of farm animals.

Dopamine (DA) and 5-hydroxytryptamine (5-HT) were measured in several regions of the pituitary gland of Jersey steers, Soay ewes and two breeds of pigs. The glands were collected from animals which had not been stressed and the amine concentrations were comparable to those found previously in the pituitary glands of laboratory animals. Metabolites of both amines were present in the infundibulum, the pituitary stalk, the combined neural and intermediate lobe and the anterior lobe of all glands analysed indicating that the amines are being utilized in these structures under "near physiological" conditions.

Animals↗
PubMed1986

Dehydration increases the electrically evoked dopamine release from the neural and intermediate lobes of the rat hypophysis.

The effect of dehydration on dopamine (DA) release from the neural and intermediate lobes of the rat pituitary gland after electrical stimulation of the pituitary stalk was studied in vitro. The amount of DA released from pituitary lobes of dehydrated rats (no water for 72 h), in which the hormone secretion from the hypophysis, especially the neural lobe, is known to be greatly enhanced, was significantly higher when compared with that from control tissues. In control and dehydrated rats the evoked DA release from the intermediate lobe was higher than that from the neural lobe. After dehydration, the stimulus-evoked DA release from the neural lobe increased by more than 200%, whereas that from the intermediate lobe increased by only 60%, indicating a preferential activation of the DA system of the neural lobe. There was a decrease in DA released per pulse from the combined neuro-intermediate lobe of control rats with increasing number of stimulation pulses. In contrast, DA release per pulse from the neuro-intermediate lobe of dehydrated rats showed a tendency to increase with increasing number of pulses. As the availability of newly synthesized DA is believed to be the limiting factor for transmitter release, the present observations suggested a higher in vitro DA synthesis rate in the tissues from dehydrated rats. This agrees with in vivo results of Alper and his colleagues who found an increased accumulation of L-3,4-dihydroxyphenylalanine (DOPA) in neuro-intermediate lobes of dehydrated rats after inhibition of DOPA-decarboxylase.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1985

Pituitary 5-hydroxytryptamine nerves--a possible link with pituitary hormone secretion.

A short review of the present knowledge on the innervation of the pituitary gland by 5-hydroxytryptamine (5-HT) containing nerves is given. This is followed by results of recent experiments in which the concentrations of 5-HT in different lobes of the rat hypophysis were measured under conditions in which pituitary hormone secretion was increased. A prolonged increase in hormone secretion induced by dehydration and increased sodium chloride intake resulted in a decrease in the 5-HT concentrations in the anterior lobe (AL). The 5-HT content of the neural (NL) and the intermediate lobe (IL) of these rats was hardly changed whereas that of DA was about doubled. Acute stimulation of pituitary hormone secretion by exsanguination under ether anaesthesia also caused a fall in the 5-HT content of the AL. In contrast, in the NL and in the IL of these rats, the 5-HT concentrations were significantly increased. This indicates that the 5-HT system in the AL reacts differently from those in the NL and IL. Pituitary dopamine (DA) contents were not affected by ether and exsanguination. Thus, the pituitary DA and the pituitary 5-HT neuronal systems are activated independently in different endocrine states. The concentrations of 5-HT were also measured in 10 groups of normal male or female rats in the course of 2 years and compared with those of DA. The concentrations of 5-HT were lowest in the AL with little variation between the different groups. In the rest of the tubero-hypophyseal system the concentrations of 5-HT were at least 3, and up to 10 times, higher than in the AL, with larger inter group variations. The DA concentrations in the AL were only 10-20% of those of 5-HT; in the other regions they were equal to or higher than those of 5-HT.

Acute Disease↗
PubMed1983

Intravenous cholecystokinin octapeptide in pigs reduces operant responding for food, water, sucrose solution or radiant heat.

The effect of intravenous injections of 0 (Saline vehicle), 10, 20 or 40 units of CCK was studied in pigs performing operant responses for food, water, sucrose solution or radiant heat. In hungry pigs working for food, thirsty pigs responding for water, and non-deprived pigs working for sucrose, 20 and 40 units CCK produced significant dose-related decreases in response rates lasting for about 5 min. In pigs responding for 10 sec bursts of infra-red heat at an ambient temperature of 5 degrees C, 40 units CCK significantly reduced the response rate during the 5 min period following injection.

Animals↗