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Biomedical subjects

D Woolley

Publications and source records attributed to D Woolley.

17 recordsLinked to original sources
PubMed2000

The molecular motors of cilia and eukaryotic flagella.

Axonemal dyneins occur in two rows (as inner and outer arms) on each of the nine doublets. Axonemal dynein binds reversibly to the B-microtubule and has an ATP-insensitive anchorage to the A-microtubule of the adjacent doublet. The heavy chains have the form of globular heads and are responsible for chemo-mechanical transduction. The B-tubule-binding site is on a tenuous extension of the head. There is only one type of ODA. A 12 nm shift in the globular heads is associated with the hydrolysis cycle. There are three types of IDA. No functional changes have been recognized in their complex conformation. There is plentiful evidence that the axonemal dyneins produce interdoublet displacement. Doubt remains on how much sliding occurs per cycle of ATP hydrolysis. The mechanism for transforming sliding into bending is not yet explained.

Animals↗
PubMed1997

Family medicine residents' and community physicians' concerns about patient truthfulness.

PURPOSE: To assess how often family physicians question patient truthfulness, what factors influence them to do so, and how often resident physicians experience such doubts as compared with senior physicians. METHOD: In 1994-95, after half-day patient care sessions, 44 residents from the University of Kansas School of Medicine's three Wichita family practice residency programs and nine community family physicians associated with the programs recorded their impressions of each patient's truthfulness, what issues prompted concern about patient truthfulness, and their feelings about each encounter. RESULTS: The residents doubted patients in 54 of 277 encounters (19.5%); the senior physicians doubted patients in 16 of 183 encounters (8.7%) (p = .003). Both groups had more negative than positive emotions toward such encounters, with no significant difference in feelings. The demographics of the resident and senior physician populations differed greatly. CONCLUSION: Although preliminary, the present study suggests that family physicians question patient truthfulness fairly often, resident physicians more than senior physicians, and that these physicians have some negative feelings toward such situations. Because such feelings may contribute to inadequate patient care, the authors recommend that further research is warranted to understand contributing factors and to guide the development of resident and student education programs in this neglected area of the doctor-patient relationship.

Attitude of Health Personnel↗
PubMed1997

Does early supplementation affect long-term breastfeeding?

The purpose of this secondary data analysis from two different samples was to examine the effect of early supplementation with manufactured milks on breastfeeding status at 20 weeks postpartum in mothers of healthy term infants. In two convenience samples of 120 and 223, respectively, breastfeeding mothers were followed up for 20 weeks postpartum or until weaning occurred. The breastfeeding rate at 20 weeks postpartum was significantly greater for mothers who reported feeding exclusively mother's milk the second week after delivery compared with mothers who breastfed and simultaneously supplemented with manufactured infant milks. Of the mothers in samples one and two who exclusively fed human milk during week 2 postpartum, 63.0% and 59.7%, respectively, were still breastfeeding at week 20, compared with 28.1% and 24.2%, respectively, who supplemented with artificial milks. There was no significant difference between these two groups of mothers and their intended duration of breastfeeding. Early introduction of supplemental bottles of artificial milks is associated with a decrease in the amount of human milk the infant receives as well as with early weaning.

Bottle Feeding↗
PubMed1996

A second look at the second stage of labor.

This article focuses on the primary clinical issues during the second stage of labor: diagnosis, duration, maternal bearing-down efforts, and fetal descent, and ways to help women with their expulsive efforts during this time. A pattern of progression for the second stage/expulsive phase of labor is presented, with an emphasis on the importance of delaying direction to or encouragement of the woman to push until the obstetric conditions are optimal for descent and the women has entered the active phase of the second stage. Ongoing assessment of fetal status and descent, the quality of uterine contractions, and maternal condition are emphasized, rather than arbitrary time limits for the second stage. The use of various care practices, including maternal position and alternative bearing-down techniques, which optimize maternal and fetal outcomes, is described. Finally, women's concerns about this major life experience are considered in the context of the care that they receive during the second stage of labor.

Cervix Uteri↗
PubMed1993

Catabolism of intact type VI collagen microfibrils: susceptibility to degradation by serine proteinases.

We present the first direct biochemical evidence for the turnover of intact type VI collagen microfibrils. Matrix-degrading enzymes of the serine proteinase class, including rat mast cell chymases I and II, human mast cell tryptase, neutrophil elastase, cathepsin G and trypsin, were able to catabolize intact type VI collagen microfibrils isolated from foetal bovine skin and metabolically labelled intact type VI collagen immunoprecipitated from fibroblast culture medium. By contrast, intact type VI collagen was not degraded by the human matrix metalloproteinases, MMP-1, MMP-2, MMP-3 and MMP-9. These data have important implications for the stability of type VI collagen in connective tissues and highlight the potential role of serine proteinases both in normal type VI collagen turnover and in inflammatory conditions characterized by matrix degradation.

Animals↗
PubMed1992

Comparison of electrocardiogram interpretations by family physicians, a computer, and a cardiology service.

BACKGROUND: Some family physicians may be under pressure to relinquish the interpretation of outpatient electrocardiograms to cardiologists. The purpose of this study was to determine whether the quality of electrocardiogram (ECG) interpretations by family physicians justifies this pressure, and whether an immediately available computerized ECG interpretation program could serve as an appropriate backup for the family physician. METHODS: Family practice faculty and residents at a university-based residency program provided written interpretations of 301 ECGs ordered over an 11-month period. Their ECG findings were compared with those from a computerized interpretation program and the readings of the cardiology service. All interpretations were then compared with those of a fellowship-trained electrocardiographer, whose readings served as the reference standard. RESULTS: Discrepancy was found between the family physician and the electrocardiographer on 33% of those items that had any potential clinical significance. The computer interpretation and the cardiologist's interpretation agreed with that of the electrocardiographer on 63% and 71% of these discrepancies, respectively (not statistically different). CONCLUSIONS: Family physicians reached a level of agreement with the reference standard in ECG interpretation that was comparable to previously published reports for expert interrater agreement. In this study, however, the quality of ECG readings by family physicians was further improved by expert review. The quality of computer-assisted ECG interpretation was comparable to that of review provided by a cardiology service. Furthermore, computerized interpretation may be clinically more useful because it is immediately available.

Aged↗
PubMed1992

Grasping the marketing nettle. A professional development course for nurse practitioners in stoma care.

Effective management and efficient use of resources are prerequisites for a high quality service. Marketing skills are now essential for nurses. These consist of nurses being able to prove they can offer an economically viable service and to argue the case for more resources. Regular use of patient questionnaires will elicit opinions on standards of care. The health service's biggest resource is its staff: improving channels of communication and creating areas of accountability will fulfil its potential.

Humans↗
PubMed1987

Catalytic properties of the yeast phospholipid transfer protein.

The properties of the phosphatidylcholine (PC) transfer reaction catalyzed by the yeast phospholipid transfer protein (TP-I) were examined in vitro. Donor and acceptor membranes consisted of unilamellar (ULV) and multilamellar (MLV) vesicles, respectively. The phospholipid composition of the membranes participating in the transfer reaction, and in particular that of the MLV acceptors, have a tremendous effect upon the rate of PC-catalyzed transfer. Phosphatidylethanolamine (PE) is an essential component of the acceptor membrane, but it alone is not sufficient to sustain appreciable transfer rates. If combined in an equimolar ratio with PC, there is only a modest increase in transfer rates. On the other hand, when combined with alternate substrates such as phosphatidylinositol (PI) or phosphatidylserine (PS), very high rates of PC transfer occur. The measurement of transfer rates is not affected by the molecular species of PC used as the radioactive tracer. Evidence is also presented to indicate that the two forms of the transfer protein (TP-I and TP-II) are not identical in terms of their interactions with a membrane surface: differences occur in the levels of transfer of PC, PE, PI, and PS at equilibrium. Finally, by kinetic analysis, the mechanism of the protein-catalyzed transfer of PC is shown to conform to a ping-pong bibi model with excess substrate inhibition, analogous to ordinary two-substrate enzyme-catalyzed reactions. Both the rates of desorption and adsorption of the protein from the surface of the ULV are much greater than those describing the similar interactions of the protein with MLV.(ABSTRACT TRUNCATED AT 250 WORDS)

Carrier Proteins↗
PubMed1985

Does phenobarbital protect against trimethyltin-induced neuropathology of limbic structures?

Because of the similarity in the pattern of limbic sites damaged by both compounds, it has been suggested that trimethyltin (TMT) may be an excitotoxin like kainic acid (KA). KA produces seizures which eventually result in neuronal damage similar to that found in epilepsy. Anticonvulsants reduce both the seizures and pathology associated with KA. Because TMT may also produce seizures, we undertook to determine whether or not some of the TMT-induced limbic neuropathology could result from seizure activity. To do this, a single dose of TMT chloride (either 7.5 or 15 mg/kg) was given per os to rats, and then phenobarbital (30 mg/kg) was administered subcutaneously in repeated doses. Treatment with phenobarbital did not prevent pathologic changes in the hippocampus, dentate gyrus, and pyriform or prepyriform cortex. Since phenobarbital did not protect against TMT-induced neuronal damage, as it has been reported by others to protect against KA-induced damage, the present findings suggest that these two toxicants probably produce hippocampal pathology via different mechanisms and that the TMT-induced pathologic changes do not require sustained electrical seizure activity.

Animals↗
PubMed1984

Time course of the effects of trimethyltin on limbic evoked potentials and distribution of tin in blood and brain in the rat.

The averaged evoked potential technique was used to determine the sequence and relative effects of a single dose of trimethyltin (TMT) on the neurophysiologic functioning of two limbic system pathways, selected for study because they are known to show TMT-induced pathologic changes. Adult female rats were implanted with bipolar electrodes in the olfactory or prepyriform cortex (PPC), dentate gyrus (DG) and distal CA3 subfield of the hippocampus. Evoked potentials were elicited in the DG by stimulation of the PPC, and in CA3 by stimulation of the mossy fiber system which originates in dentate granule cells. TMT chloride was administered po in a single 7.5 mg/kg dose in water to 9 implanted rats. A parallel group of 6 implanted rats served as a control group. No changes in potentials were noted 24 hr after TMT, but some effects appeared at 48 hr. Amplitudes of potentials elicited in the DG were greatly potentiated between 2-7 days after TMT with peak effects between 4-6 days, followed by a marked decline in amplitude of the response. At the same time, recordings of spontaneous electrical activity did not reveal marked abnormalities such as electrographic seizure waves. Amplitude of the CA3 response began to decline 3 days after TMT and by 3 weeks was markedly depressed. Average amplitudes of the same responses in the control group remained within 12 percent of pretreatment values for the 20 days of the study. Tin levels in whole brain were lowest at 24 hr, doubled at 48 hr, then doubled again at 4 days when peak levels were reached. Values remained high in both blood and brain and at 20 days were still 66 percent of peak levels. Thus, the delay in onset of effects of TMT on evoked potentials may be related to the slow entry of tin into brain, presumably because of high affinity binding to hemoglobin in blood, as reported by others. Also, the time of peak potentiating effects on potentials evoked in the DG correlated well with the time of peak levels of tin in brain.

Animals↗
PubMed1976

In vivo nuclear 3H-estradiol binding in brain areas of the rat: reduction by endogenous and exogenous androgens.

In vivo specific nuclear binding of [2, 4, 6, 7 (n)-3H]estradiol (3H-E2) as indicated by diethylstilbestrol (DES)-blockable radioactivity, was measured 1 h after injection in adult intact male, untreated and testosterone propionate (TP)-pretreated or 5alpha-dihydrotestosterone (DHT)-pretreated gonadectomized (GDX) male and female rats. There was no sex difference in specific 3H-E2 binding in brain areas and anterior pituitary (PIT) of untreated GDX animals. DHT pretreatment had no effect on binding in any tissue. Specific nuclear binding in the preoptic area-anterior hypothalamus (POA-AH), median eminence-basal hypothalamus (ME-BH), amygdala (AMYG), septum (SEP), and dorsal hypothalamus (DH) was lower in intact males and TP-pretreated GDX males and females than in untreated GDX animals. Uptake in the PIT was not affected by TP pretreatment or by the presence of the testes, suggesting that the reduction in nuclear 3H-E2 binding observed in other tissues was caused by competition by estradiol formed in situ from TP or endogenous androgens for nuclear binding sites. Thus, the reduction in 3H-E2 uptake caused by the presence of TP or the testes could be used to estimate the degree of aromatization that occurred in these brain areas. In males, specific nuclear binding of 3H-E2 was reduced by the presence of the testes by 60-70% in the POA-AH and AMYG, by 30-40% in the ME-BH and SEP and by 0-20% in the DH. After s.c. administration of 1 mg/kg TP in GDX males, the amount of estrogen formed after 1,5 h in these same tissues approximated that present in the steady state in intact males. This suggests that, in the intact adult male rat, a high percent of estradiol nuclear binding sites in some brain areas is normally occupied by the products of aromatization.

Amygdala↗