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Biomedical subjects

M Lewis

Publications and source records attributed to M Lewis.

At least 217 records · Page 12Linked to original sources
PubMed1995

[Temporal trends in myocardial infarct morbidity, mortality and 28-day fatalities and medical management. Results of the Augsburg Myocardial Infarct Register 1985 to 1992].

Between 1985 and 1992 a significant decrease in rates of acute myocardial infarction (AMI; fatal and non fatal, including prehospital cardiac death) from 533 cases per 100,000 population of 455 cases was observed in the 25- to 74-year-old male study population (linear regression model: -13%, p < 0.01). In the corresponding female study population the AMI rate increased from 153 cases per 100,000 population in 1985 to 153 cases in 1992 (linear regression model: +18%, p < 0.05). The decrease was only in 50- to 59-year-old male AMI patients without changes in risk factors (smoking, diabetes, hypertension, recurrent AMI) but with a decrease in patients with a history of angina pectoris, which may have been caused by intensified medical treatment of AMI endangered patients. Over time 34% of the patients died before hospitalization and another 19% died within the first 24 h after hospitalization. The register results show an underestimation of the coronary mortality by the official cause of death statistics. In contrast, the significant increase in treatment with thrombolytics (men from 16% to 38%, women from 8% to 42%), beta-blockers (men from 48% to 69%, women from 45% to 71%), and antiplatelets (men from 55% to 94%, women from 52% to 91%) was not related to any significant changes in 28-day case fatality of the 24-h survivors (men and women 13% to 14%). Without media campaigns, for the increased number of cases hospitalized within 4 h after the event (1985-1987 men 50%, women 42%; 1990-1992 58% and 60%; p < 0.01) thrombolytic treatment shows an increase from 25% in men and 17% in women (1985-1987) to 54% in men and 47% in women (1990-1992; p < 0.01).

Adult↗
PubMed1995

The effects of birth condition on infants' cortisol response to stress.

UNLABELLED: OBJECTIVE, DESIGN, AND SUBJECTS: To examine the effects of nonoptimal birth condition on cortisol response to routine inoculation in a longitudinal sample of full-term healthy infants at 2, 4, and 6 months of age. MEASUREMENT AND MAIN RESULTS: Optimal versus non-optimal birth condition was defined by a large versus small head circumference and a high versus low 1-minute Apgar score. An optimal birth condition was associated with a high cortisol response at 2 months, but a low cortisol response by 6 months of age. CONCLUSIONS: The findings indicate a reversal in the meaning of high adrenocortical reactivity between 2 and 6 months of age: high cortisol response may index optimal functioning at 2 months, but nonoptimal functioning by 6 months of age. Together with other results, this reversal provides evidence for a developmental shift in adrenocortical functioning during this period. The findings also show that the effects of a nonoptimal birth condition in otherwise healthy full-term infants persist for at least the first 6 months of life.

Analysis of Variance↗
PubMed1995

Memory and psychoanalysis: a new look at infantile amnesia and transference.

OBJECTIVE: This article reexamines the psychoanalytic concepts of infantile amnesia and transference in the light of certain findings derived from neurobiological research, information-processing theory, child development research, cognitive-developmental theory, and, more speculatively, evolutionary theory concerning memory. METHOD: Relevant developments from recent research in the neurosciences, and psychopathological phenomena in two psychiatric disorders--posttraumatic stress disorder and child abuse--in which memory changes are of critical importance, are first reviewed briefly. Four alternative hypotheses for infantile amnesia and three for transference are then derived from this review. RESULTS: The hypotheses discussed provide plausible alternative explanations for at least part of the phenomena classically subsumed in the psychoanalytic concepts of infantile amnesia and transference. CONCLUSIONS: Neurobiological, information-processing, developmental shifts, cognitive-developmental, and evolutionary findings and theories provide alternative hypotheses for infantile amnesia and transference that suggest a need for revisions and redefinitions for these two psychoanalytic concepts.

Child↗
PubMed1995

Effects of intraventricular hemorrhage and other medical and environmental risks on multiple outcomes at age three years.

This study examined the interrelated effects of intraventricular hemorrhage (IVH), neonatal medical condition, and environmental quality on development. At age 3 years, the functioning of 105 preterms was assessed in a variety of cognitive areas. Analyses revealed that IVH was related to gross motor, receptive, and expressive communication ability. However, it was only the subjects who had severe IVH who performed significantly worse than the comparison subjects. Subjects who had hemorrhages confined to a germinal matrix or a small intraventricular bleed did not differ from the comparison subjects who performed at expected age levels. When medical condition, socioeconomic status, and family risk, a composite variable including proximal environmental measures, were examined together with IVH as predictors, IVH remained related to motor and receptive communication ability after controlling for the other variables. The number of other medical complications and the environmental factors had more wide-ranging effects. Each predictor was related to a unique set of outcomes.

Cerebral Hemorrhage↗
PubMed1995

Routine omentectomy is not required in children undergoing chronic peritoneal dialysis.

A routine omentectomy is recommended in children commencing chronic peritoneal dialysis, but is not routine practice in adults. We reviewed the outcome of 66 catheters (57 straight and 9 spiral) inserted into 38 patients (median age 7.8 years, 12 patients under 2 years) over a period of 4.8 years. The aim of the study was to determine whether an omentectomy affects the incidence of catheter blockage or peritonitis. Mean catheter life was 6.8 months (range 0.2-28 months). Fifteen are still in situ, and 14 were removed electively (transplantation). Blockage occurred in 1/22 catheters inserted after an omentectomy, compared with 10/44 inserted without an omentectomy (absolute risk reduction with omentectomy = 0.18). Blockage was more frequent with spiral catheters (4/9 vs 7/57; p < 0.05). Thirty-seven catheters were associated with one or more episodes of peritonitis. Peritonitis was not significantly more frequent after omentectomy. We conclude that a routine omentectomy is not routinely indicated in children commencing chronic peritoneal dialysis. Eleven omentectomies are required to prevent two omental blockages (1/0.18), and secondary omentectomy after blockage is a straightforward procedure. Spiral catheters conferred no benefit in this study. Omentectomy does not influence the incidence of peritonitis.

Adolescent↗
PubMed1994

Using genetic algorithms for solving heavy-atom sites.

A novel procedure has been developed for locating heavy-atom positions in crystals of macromolecules. This method used genetic algorithms (GA's) to search for heavy-atom sites that are consistent with an observed difference Patterson function. The procedure is straightforward to apply, space-group independent, and particularly powerful for cases involving non-crystallographic symmetry of multiple heavy atoms in the asymmetric unit. In this paper, we introduce how GA's are used for determining the heavy-atom positions and show how this method is more efficient than a sequential search.

Journal Article↗
PubMed1994

Three-dimensional structure of rat liver 3 alpha-hydroxysteroid/dihydrodiol dehydrogenase: a member of the aldo-keto reductase superfamily.

The 3.0-A-resolution x-ray structure of rat liver 3 alpha-hydroxysteroid dehydrogenase/dihydrodiol dehydrogenase (3 alpha-HSD, EC 1.1.1.50) was determined by molecular replacement using human placental aldose reductase as the search model. The protein folds into an alpha/beta or triose-phosphate isomerase barrel and lacks a canonical Rossmann fold for binding pyridine nucleotide. The structure contains a concentration of hydrophobic amino acids that lie in a cavity near the top of the barrel and that are presumed to be involved in binding hydrophobic substrates (steroids, prostaglandins, and polycyclic aromatic hydrocarbons) and inhibitors (nonsteroidal antiinflammatory drugs). At the distal end of this cavity lie three residues in close proximity that have been implicated in catalysis by site-directed mutagenesis--Tyr-55, Asp-50, and Lys-84. Tyr-55 is postulated to act as the general acid. 3 alpha-HSD shares significant sequence identity with other HSDs that belong to the aldo-keto reductase superfamily and these may show similar architecture. Other members of this family include prostaglandin F synthase and rho-crystallin. By contrast, 3 alpha-HSD shares no sequence identity with HSDs that are members of the short-chain alcohol dehydrogenase family but does contain the Tyr-Xaa-Xaa-Xaa-Lys consensus sequence implicated in catalysis in this family. In the 3 alpha-HSD structure these residues are on the periphery of the barrel and are unlikely to participate in catalysis.

3-Hydroxysteroid Dehydrogenases↗
PubMed1994

In vivo transfection by hepatitis A virus synthetic RNA.

Marmosets injected intrahepatically with nucleic acids (cDNA and RNA transcripts) representing the full-length genome of the wild-type HM-175 strain of hepatitis A virus experienced acute hepatitis and seroconversion to hepatitis A virus capsid proteins. The hepatitis was comparable in severity to that caused by infection with the wild-type virus. The viral cDNA and the hepatitis A virus recovered from the feces of an injected animal contained the same marker mutation. Therefore, intermediate cell culture steps can be omitted and the virulence of a hepatitis A virus encoded by a cDNA clone can be evaluated by direct transfection of marmosets.

Animals↗
PubMed1994

[Drug treatment of patients with heart infarcts before and after the acute stage: results of the Heart Infarct Registry Augsburg].

To assess the changes in medications prescribed before and after acute myocardial infarction (AMI), all surviving patients aged 25-74 years registered from 1985-1988 in the Coronary Event Register Augsburg were evaluated by sex, medical history, and drug use before and after the event. For the 1546 hospitalized patients (1181 men, 365 women) utilization of all drug groups is higher for patients with reinfarction than for patients with first-ever AMI. Before AMI, but not on hospital discharge, women received significantly more medications than men and were more frequently treated with diuretics (30%; men 18%), antihypertensive drugs (15%, men 8%) and cardiac glycosides (20%; men 14%). The most frequently used drug groups are nitrates (before AMI: 30%; after AMI: 80%) and calcium antagonists (before AMI: 26%; after AMI 61%). The four years show a significant increase in patients with reinfarction who were treated with platelet aggregation inhibitors (1985: 9%; 1988: 32%), as well as an increase in AMI patients released from hospital with this medication (1985: 38%; 1988: 64%). A concomitant significant decrease in reinfarction rates for men is found in the course of the four years under study. The results indicate a rapid assimilation of the results of clinical trials in practice down to the substance level.

Acute Disease↗
PubMed1994

Amniotic fluid erythropoietin levels in normal and Down's syndrome pregnancies.

The aim of this study was to measure the levels of erythropoietin in amniotic fluid from normal and trisomy 21 pregnancies at 10 to 20 weeks gestation. Samples of amniotic fluid were collected from 142 women with singleton pregnancies after genetic amniocentesis; 110 had a normal fetal karyotype and 32 had trisomy 21. Erythropoietin was measured using a double antibody radioimmunoassay. Amniotic fluid erythropoietin levels in normal pregnancies increased from 10 weeks (mean 3.2 mU/ml; range < 2.0-6.3 mU/ml) to 20 weeks gestation (mean 7.9 mU/ml; range 2.0-11.5 mU/ml). There was a significant linear correlation between gestational age and erythropoietin levels (r = 0.543; P < 0.0001). For the 32 patients with trisomy 21 pregnancies the median multiple of the median (MoM) was 1.11 (range 0.42-2.1). There was no difference between erythropoietin levels in amniotic fluid from normal and Down's syndrome pregnancies (U = 2352, P = 0.75, 95% CI = -0.11, 0.18); (Mann-Whitney U-test).

Amniotic Fluid↗
PubMed1994

Spinal anaesthesia for caesarean section: comparison of infusions of phenylephrine and ephedrine.

Maternal cardiovascular changes and neonatal acid-base status were assessed in 29 healthy women undergoing elective lower segment Caesarean section under spinal anaesthesia. The patients were allocated randomly to one of three groups to receive an i.v. infusion of one of the following: ephedrine 1 mg min-1 (group E1: n = 10), ephedrine 2 mg min-1 (group E2: n = 9), or phenylephrine 10 micrograms min-1 (group P: n = 10). Invasive arterial pressure was monitored continuously and if hypotension occurred (defined as a 20% decrease from baseline, taken after i.v. preload administration), bolus doses of either ephedrine (6 mg in groups E1 and E2) or phenylephrine (20 micrograms in group P) were given. Only four patients became hypotensive in group E2, compared with eight patients in group E1 and nine patients in group P. The total time that the patients remained hypotensive was greatest in group P (P < 0.005), less in group E1 and least in group E2. Neonatal Apgar scores and acid-base profiles were similar in all three groups. In this study, an infusion of phenylephrine 10 micrograms min-1 with bolus doses of 20 micrograms was shown to be significantly less effective in maintaining systolic arterial pressure within 20% limits of baseline compared with an infusion of ephedrine 1 or 2 mg min-1 with bolus doses of 6 mg.

Adult↗
PubMed1994

Comparison of invasive and non-invasive measurement of continuous arterial pressure using the Finapres in patients undergoing spinal anaesthesia for lower segment caesarean section.

We have compared arterial pressures measured by an indwelling radial cannula with those obtained non-invasively by the Finapres 2000 (Ohmeda) during spinal anaesthesia for lower segment Caesarean section. The digital outputs of both pressures were recorded using a computerized system. We studied 20 patients, yielding a total of 18,772 data points after elimination of data recorded during arterial flushing and erroneous results from each source. The data analysis demonstrated a normal distribution for differences between the two methods of measurement, and the correlations between invasive and Finapres readings for systolic, diastolic and mean pressures were 0.78, 0.72 and 0.79, respectively, indicating an overall poor reflection of intra-arterial pressure by the Finapres under these circumstances. Some patients and some periods of readings reflected a high degree of precision and little bias. However, unexplained large differences in pressure and trends of change that were out of phase over time occurred frequently. We conclude that the Finapres cannot be recommended as a monitor of arterial pressure in this group of patients in whom sudden hypotension may be a threat to maternal or fetal outcome.

Anesthesia, Obstetrical↗
PubMed1994

What is the best way to determine oropharyngeal classification and mandibular space length to predict difficult laryngoscopy?

BACKGROUND: Previous studies have suggested that the degree of visibility of oropharyngeal structures (OP class) and mandibular space (MS) length can predict difficult laryngoscopy. However, those studies were either inconsistent or omit description of how to perform these tests with regard to body, head and tongue position, and the use of phonation, hyoid versus thyroid cartilage and inside versus outside of the mentum. The purpose of this investigation was to determine which method of testing best predicts difficult laryngoscopy. METHODS: In each of 213 consenting adults the OP class was determined in 24 method combinations: two body positions (sitting and supine), three head positions (neutral, sniff, and full extension), two tongue positions (in and out), and with and without phonation. In each patient MS length was measured in 24 method combinations: two body positions (sitting and supine), three head positions (neutral, sniff, and full extension), two distal end points (hyoid and thyroid cartilage), and two proximal end points (inside and outside of the mentum). In each patient the laryngoscopic grade was determined at the time of induction of anesthesia. We defined laryngoscopic grades III (n = 24) and 4 (n = 0) as difficult. The area under the receiver operating characteristic curve (ROC area) for each combination was used to compare the combinations and determine significant differences: ROC area = 0.5 implied a totally uninformative combination and ROC area = 1.0 a combination that predicted perfectly. Logistic regression analysis was used to calculate a predictor of difficult intubation that combined both OP class and MS length (the performance index). The performance index could then be used to calculate sensitivity, specificity, positive and negative predictive value, and probability of difficult intubation. RESULTS: The ROC areas for the different combinations used to assess OP class ranged from 0.78 to 0.94. The best combination was with the patient sitting, head in extension, tongue out, and with or without phonation. For MS length, the ROC areas ranged from 0.58 to 0.77; the best combination was the patient sitting, with the head in extension, with distance measured from the inside of the mentum to the thyroid cartilage. Combining the OP class and MS length (performance index = 2.5 X OP class - MS length in centimeters) significantly increased predictability of difficult intubation. At performance index = 0 and = 2, the probability of difficult intubation was 3.5% and 24%, respectively. With clinically relevant cutpoints for the performance index it was found that most difficult intubations could be predicted, but approximately half of those predicted to be difficult would in fact be easy. CONCLUSIONS: Based on the above ROC areas and ease of performing the test for the patient, we recommend that these tests be performed with patients in the sitting position, with the head in full extension, the tongue out, and with phonation, and with distance measured from the thyroid cartilage to inside of the mentum. Nevertheless, it is clear that these two tests, either used alone or in combination, will fail to predict a few difficult laryngoscopies and that they will predict difficult laryngoscopy in a significant number of patients in whom the trachea is easy to intubate.

Adult↗
PubMed1994

Developmental change in infant cortisol and behavioral response to inoculation.

Infant cortisol and behavioral responses to receiving 1 versus 2 inoculations on 1 pediatric office visit were observed at 2 and 6 months of age. Cortisol level (pre- plus postinoculation level) decreased with age, whereas cortisol response (post- minus preinoculation level) did not vary with age when the data were aggregated over infants showing a pre- to postinoculation cortisol increase and those showing a decrease. Nonetheless, for those infants who showed a cortisol increase, cortisol level and response decreased with age. Infants quieted faster at the older age. There was a moderate relation between quieting behavior and cortisol response, at least for infants who showed a pre- to postinoculation cortisol increase. These findings indicate a developmental trend for a decline over age in adrenocortical reactivity to inoculation for infants showing a cortisol release following the perturbation. Results were comparable whether infants received 1 or 2 inoculations.

Diphtheria-Tetanus-Pertussis Vaccine↗
PubMed1994

Weekly variation of acute myocardial infarction. Increased Monday risk in the working population.

BACKGROUND: Seasonal and circadian variations in the occurrence of myocardial infarction and sudden cardiac death have been documented, suggesting that triggering factors may play a role in the causation of cardiac events. However, there are only sparse and conflicting data on the weekly distribution of the disorders. METHODS AND RESULTS: To determine the weekly variation of acute myocardial infarction and sudden cardiac death, 5596 consecutive patients (71% men; age, 63 +/- 1 years) were analyzed in a regionally defined population (n = 330,000; age, 25 to 74 years) monitored from 1985 to 1990. The exact time of onset of symptoms was used to determine the day of the event. Patients with myocardial infarction (n = 2636) demonstrated a significant weekly variation (P < .01) with a peak on Monday, whereas patients with sudden cardiac death (n = 2960) were evenly distributed throughout the week. A similar weekly pattern was observed in subgroups of patients with myocardial infarction defined with respect to age, sex, cardiac risk factors, prior cardiac medication, and infarct characteristics. The working population demonstrated a weekly variation of myocardial infarction as opposed to the nonworking population, with a 33% increase in relative risk of disease onset on Monday (P < .05) and a trough on Sunday compared with the expected number of cases, if homogeneity was assumed. CONCLUSIONS: The onset of acute myocardial infarction demonstrates a peak on Monday primarily in the working population. If this finding is confirmed in other communities, it may aid in identifying acute triggering events of myocardial infarction and perhaps in improving prevention of the disease.

Adult↗