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Biomedical subjects

L Williams

Publications and source records attributed to L Williams.

At least 217 records · Page 12Linked to original sources
PubMed1990

Organization of the auditory pathway in the thoracic ganglia of noctuid moths.

We describe the neuroarchitecture of the noctuid thoracic nerve cord and use this framework to interpret the organization of the auditory pathway responsible for escape behaviour in noctuid moths. Noctuid moths possess only two auditory receptors (A1, A2), in each ear. The axon of the A1 cell projects initially to a glomerulus located ventrally and medially in the metathoracic ganglion, where it bifurcates. One branch ascends in the ventral intermediate tract to the brain, the other descends in the ventral intermediate tract into abdominal neuromeres of the metathoracic ganglion. Both axons arborize in the median ventral and ring tracts in each neuromere. The central projections of the A2 cell remain largely within the metathoracic ganglion. The axon bifurcates at the midline and directs arborizations dorsally to the dorsal intermediate and median dorsal tracts, and ventrally into the ring tract where the arborizations overlap those of the A1 afferent. The afferent projections remain ipsilateral to the ear of origin. We describe a posterior auditory association area in the metathoracic ganglion in which the major arborizations of several identified interneurones overlap those of the A1 afferent and make monosynaptic connections with it. These interneurones all respond tonically to sound stimuli. We have also identified the projections of the A1 afferent, interneurones, and motor neurones in the segmentally equivalent anterior auditory association area of the mesothoracic ganglion. An interneurone with major arborizations in the same tracts as the A1 afferent, and receiving monosynaptic input from it, is described. The arborizations of higher order interneurones lie mainly in dorsal tracts along with those of flight motor neurones. All the interneurones in this anterior centre respond phasically or phasic/tonically to sound stimuli. The relevance of this anatomical organization for predator avoidance behaviour is considered and the organization of auditory pathways in tympanate insects compared.

Animals↗
PubMed1990

Long-term cost-effectiveness of various initial monotherapies for mild to moderate hypertension.

To evaluate the comparative efficacy and cost-effectiveness of various antihypertensive medications in persons aged 35 through 64 years with diastolic blood pressure of 95 mm Hg or greater and no known coronary heart disease, we used the Coronary Heart Disease Policy Model, which is a computer simulation of overall mortality as well as the mortality, morbidity, and cost of coronary heart disease in the US population. From the pooled literature, we estimated the antihypertensive and total cholesterol effects of various antihypertensive regimens. For 20 years of simulated therapy from 1990 through 2010, the cost per year of life saved was projected to be $10,900 for propranolol hydrochloride; $16,400 for hydrochlorothiazide; $31,600 for nifedipine; $61,900 for prazosin hydrochloride; and $72,100 for captopril. Doubling the cholesterol effects of the agents under study did not significantly change their effectiveness because, in general, lowering diastolic blood pressure by 1 mm Hg was equivalent to lowering the cholesterol level by 6%. Although any projection requires multiple estimates, each of which may be open to debate, propranolol appears to be the preferred initial option under most of a variety of alternative assumptions.

Adult↗
PubMed1990

Optimal therapy for patients with biliary atresia: portoenterostomy ("Kasai" procedures) versus primary transplantation.

As the results with liver transplantation have improved, a controversy has arisen regarding the precise role of a portoenterostomy in the treatment of infants with biliary atresia. The controversy centers around three issues: (1) the short- and long-term survival rates achieved with both procedures, (2) the influence of a portoenterostomy on a subsequent transplant, and (3) the shortage of suitable liver donors for very small infants. To address these questions, we retrospectively reviewed the charts of 48 children with biliary atresia who underwent liver transplantation and compared these results with 35 children transplanted for other liver diseases. As a group, the biliary atresia patients had significantly lower mean body weights and ages and spent a significantly longer time on the waiting list. In addition, significantly more of the biliary atresia patients had undergone prior abdominal surgery when compared with the non-biliary atresia group. There was no difference in the intraoperative variables of mean anesthesia time, mean operative time, mean anesthesia preparation time, nor the mean amount of blood transfused intraoperatively between the two groups. However, when the biliary atresia patients who had undergone a portoenterostomy with a stoma were compared with either the biliary atresia patients who did not have a stoma created as part of their portoenterostomy or the non-biliary atresia patients, significant differences were noted in mean total anesthesia time, mean operative time, and the mean amount of blood transfused intraoperatively. The survival rate of the biliary atresia patients was significantly greater than the non-biliary atresia patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Algorithms↗
PubMed1990

Gender patterns in social touch: the impact of setting and age.

This study examined the impact of age of participants and the setting in which touch occurred on gender patterns in 799 instances of observed intentional touch. Gender asymmetry, a pattern in which men are more likely to touch women than vice versa, was observed when touch between adults was examined but not when touch involving children was examined. Adult touch interactions occurring in public, nonintimate settings showed gender asymmetry, but adult touch interactions occurring in greeting or leave-taking settings did not. Cross-sex touch was more prevalent among adults, whereas same-sex touch was more prevalent when a child was involved. Implications for theoretical perspectives on gender and touch are discussed.

Adolescent↗
PubMed1990

Reduced heart lipid peroxidation precedes cardiac dilatation in turkeys with naturally occurring cardiomyopathy.

STUDY OBJECTIVE: The aim of the study was to determine if reduced heart lipid peroxidation in 1-2 month old turkeys with furazolidone induced dilated cardiomyopathy is drug related and model dependent, a non-specific characteristic of the dilated turkey heart, or if alterations of heart lipid peroxidation can occur prior to onset of cardiac dilatation, and therefore may be involved in its pathogenesis. DESIGN: Ventricular lipid peroxidation capacity and superoxide dismutase activity were measured in controls and in turkeys with spontaneous cardiomyopathy at various ages (newly hatched, 7-10 d, and 1-2 months) and stages of the disease. SUBJECTS: 46 turkeys with naturally occurring dilated cardiomyopathy and 29 age matched controls were used at hatch, 7-10 d, and 1-2 months of age. MEASUREMENTS AND MAIN RESULTS: Heart lipid peroxidation, measured by thiobarbituric acid reactive substances (malondialdehyde), was found to be reduced not only in the dilated hearts of 1-2 months old cardiomyopathic turkeys [114(SEM 10) v 176(21) nmol.100 mg-1 protein, p = 0.023] but also in the non-dilated hearts of 9-10 day old cardiomyopathic turkeys [135(17) v 274(35) nmol.100 mg-1 protein, p = 0.004]. Ventricular superoxide dismutase activity was similar in control and cardiomyopathic turkeys at all stages and there was the expected increase with age. In control turkeys ventricular superoxide dismutase activity in 1-2 month old birds, at 718(52) nitrite units.100 mg-1 protein, was significantly higher than values in 7-10 day old turkeys [398(31) nitrite units.100 mg-1 protein, p = 0.001]. CONCLUSIONS: Decreased lipid peroxidation capacity is present in the dilated hearts of spontaneously cardiomyopathic turkeys. However, it is also decreased in cardiomyopathic turkeys at 9-10 d (the time of highest mortality) prior to the onset of cardiac dilatation. Therefore, alterations in heart lipid composition may be involved in the pathogenesis of this cardiomyopathy and not simply a result of the cardiac dilatation/hypertrophy process.

Aging↗
PubMed1990

A rapid latex agglutination assay for the determination of plasma fibrinogen.

A monoclonal antibody to intact fibrinogen has been employed to develop a rapid latex agglutination assay for the estimation of plasma fibrinogen. The monoclonal antibody, 45J, recognizes an epitope located in the mid-section of the carboxy terminal end of the A alpha-chain. The epitope is destroyed by plasmin digestion of fibrinogen and there is no immunoreactivity with soluble cross-linked fibrin degradation products. The latex agglutination assay developed with the antibody is unaffected by aprotinin or anticoagulants, such as citrate, heparin or EDTA. When this method was compared with functional clotting assays, excellent correlation was observed with normal and pathological samples. After sample collection and dilution, the assay takes just two minutes to complete. Therefore, this procedure offers a simple and rapid assay for the measurement of intact fibrinogen in plasma.

Animals↗
PubMed1990

Neck masses.

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Diagnosis, Differential↗
PubMed1990

Skin cancer.

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Basal Cell Carcinoma↗
PubMed1990

Examination of the relationships among drug use, emotional/psychological problems, and crime among youths entering a juvenile detention center.

Urine testing and confidential interviews of youths entering a juvenile detention center in a southeastern city produced some striking results in regard to their drug use, delinquent behavior, and emotional/psychological problems. Recent users of marijuana/hashish and cocaine had higher rates of referral to juvenile court for property and drug offenses than nonusers. The results suggest that interviewing and urine testing of youthful detainees for drug use at the point of entry into secure detention is a promising method for screening youngsters with histories of delinquent behavior. Implications of these findings are drawn.

Adolescent↗
PubMed1990

A longitudinal study of the relationships among alcohol use, marijuana/hashish use, cocaine use, and emotional/psychological functioning problems in a cohort of high-risk youths.

There is increasing recognition that children involved in the justice system often have serious, multiple problems in the areas of physical abuse, sexual exploitation, and alcohol/other drug use (ADM). Using data collected in a longitudinal study of detained juveniles, we test a model of the relationships of these problems. Significant over-time interrelationships are found among these problems. Research and policy implications of these important findings are drawn.

Adolescent↗
PubMed1990

Spontaneous rupture of liver due to cholangitis.

Spontaneous rupture of the liver is rare in the Western world and most cases are associated with primary or metastatic tumours. Spontaneous rupture of the intrahepatic biliary tree is not well documented and only two reports have been found in the literature. The authors describe a further case due to ascending cholangitis but presenting with biliary peritonitis. The literature is reviewed and the diagnostic problems discussed.

Cholangitis↗
PubMed1990

Zeta potential and vancomycin-red blood cell interactions.

Vancomycin hydrochloride is a polycationic antibiotic that we have previously reported to cause spontaneous aggregation of red blood cells (RBCs) in vitro at concentrations of more than 3.0 mg/mL, and false-positive direct antiglobulin tests at concentrations of 2.0 and 2.5 mg/mL. These latter reactions were abolished when the RBCs were pretreated with the proteolytic enzyme ficin suggesting an interaction with sialoglycoproteins. In this study we show that prior addition of vancomycin did not block binding of antibodies to several blood group antigens, nor does vancomycin precipitate in an Ouchterlony assay with any of several sialic acid moieties. Finally, we show that vancomycin possesses fluorescent properties but fails to be detected on the RBC surface by flow cytometry. These data indicate that vancomycin may be acting through its polycationic properties. Our findings do not support protein binding of vancomycin to the RBC surface, but underline the importance of the zeta potential in RBC serologic reactions.

Erythrocyte Membrane↗