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Biomedical subjects

M Lewis

Publications and source records attributed to M Lewis.

At least 415 records · Page 23Linked to original sources
PubMed1985

Invasive pulmonary aspergillosis complicating influenza A pneumonia in a previously healthy patient.

A rare occurrence of invasive pulmonary aspergillosis complicates influenza pneumonia in a previously healthy adult. Five other similar cases are reported in the literature. Both transient depression of cell-mediated immunity and loss of ciliary function in the tracheobronchial tree occurs during acute influenzal illness and may predispose to fungal superinfection. Early diagnosis and treatment of opportunistic Aspergillus infection complicating influenza is mandatory in view of the high mortality associated with this complication.

Adult↗
PubMed1985

Molecular polarity in DNA-protein recognition--the case of lambda-repressor-operator system.

The charge distribution of lambda-repressor suggests that the molecular electrostatic polarity may accelerate the non-specific binding of the protein to the DNA molecule. The repressor molecule has a patch of positive charge within the first 26 residues which may contribute a non-specific binding surface. In addition, electrostatics may play an important role and account for why proteins form and use dimers in many specific DNA-protein recognition processes.

Bacteriophage lambda↗
PubMed1985

Trends and directions in developmental research.

Perhaps one of the most dramatic fundamental changes in our views of child development has been the relatively recent shift from Freud's view of the infant as an individual struggling to avoid displeasure to Piaget's view of an individual who from the first day of life is essentially an active initiator of all kinds of interactions with his or her environment. Subsequent interactional research shifted the focus again to the interaction among biologic, psychological, and environmental factors. Within this context, infant behavior has probably been the largest single expanding area of child development research in recent years. Some discernible trends and directions of special interest to the clinician will be noted here.

Attention Deficit Disorder with Hyperactivity↗
PubMed1985

Activated clotting time for control of anticoagulation during surgery.

Two groups of patients undergoing extracorporeal bypass were compared for heparin activity and for heparin and protamine dosage. In group I (18 patients), a uniform dosage pattern was neutralized at the end to a normal clotting time. In group II (43 patients), heparin and terminal protamine doses were regulated by activated clotting times (ACT) using a Hemochron (International Technidyne Corp., Metuchen, NJ). In group II there was a 39 per cent reduction of total heparin dose per case, protamine was reduced 76 per cent, and if the initial heparin doses were excluded, maintenance heparin was reduced 73 per cent. No pattern of heparin administration could be applied to all patients. Heparin half-life varied from 43 to 220 minutes. Other factors that alter heparin activity during bypass revealed no statistical differences. Plasma Hgb was significantly higher in group I, and platelet counts the day following operation were higher in group II. ACT allows tailoring heparin and protamine without the unnecessary dangers of variations in patient response and drug potency.

Blood Coagulation Tests↗
PubMed1984

Expression of a Drosophila heat shock protein in mammalian cells: transient association with nucleoli after heat shock.

We transformed mouse L cells with a cloned Drosophila hsp70 gene and obtained cells with either heat-inducible or constitutively expressed copies of the gene. The distribution of hsp70 in these cells was examined by indirect immunofluorescence with monoclonal antibodies specific to the Drosophila protein. In constitutive cells, hsp70 was present in both cytoplasm and nucleus. After heat shock, the nuclear hsp70 was transiently concentrated in nucleoli, from which it had previously been excluded; the cytoplasmic hsp70 moved to a perinuclear location, a result consistent with it being associated with intermediate filaments of the cytoskeleton. The nucleolar migration took several hours and was partly inhibited by actinomycin D, but was independent of protein synthesis; it may reflect binding to newly-synthesized rRNA. Drosophila hsp70 was also expressed from replicating plasmids in monkey COS cells, and was found to be concentrated in nuclei even at low temperature. Migration to nucleoli occurred after heat shock. These results indicate that a single protein can have multiple interactions with cellular components, and form the basis for future studies of these interactions by in vitro mutagenesis and expression of the hsp70 gene.

Animals↗
PubMed1984

Measurement of myocardial infarct size by technetium pyrophosphate single-photon tomography.

The primary determinant of prognosis after acute myocardial infarction (AMI) is the size of the acute infarct. The present study evaluates 46 patients with different infarct distributions and sizes to test the hypothesis that single photon emission computed tomography with technetium-99m pyrophosphate (Tc-99m-PPi) and blood pool overlay allows measurements of AMI size that provide insight into prognosis irrespective of infarct location. Identical Tc-99m-PPi and ungated blood pool projections were acquired over 180 degrees with a rotating gamma camera. Reconstructed sections were color-coded and superimposed for purposes of infarct localization. Areas of increased pyrophosphate uptake within myocardial infarcts were thresholded at 65% of peak activity. The blood pool was thresholded at 50% and subtracted so as to determine an endocardial border for the left ventricle. Using this method, myocardial infarcts weighed 2.5 to 81.2 g. The correlation of infarct mass with prognosis showed that patients without previous AMI and with acute infarcts that weighed more than 40 g had an increased frequency of death and congestive heart failure (p less than 0.001). The correlation of measured infarct mass with peak serum creatine kinase level was significant (r = 0.83, p less than 0.001; y = 0.015x + 13.20). The correlation coefficients for anterior, inferior and nontransmural AMI were not significantly different from those for the entire group. In conclusion, tomographically determined infarct mass data correlate with subsequent clinical prognosis, and Tc-99m-PPi tomography with blood pool overlay is a safe and effective means of sizing infarcts in patients with AMI.

Adult↗
PubMed1984

Isolation of Mycobacterium chelonei from a patient with recurrent aspiration pneumonia.

Non-tuberculous mycobacteria are rarely isolated in South African laboratories. Mycobacterium chelonei has previously been shown to cause pulmonary disease, especially in the clinical setting of aspiration and lipoid pneumonia. Isolation of non-tuberculous mycobacteria is not proof of pathogenicity; casual cultures may occur from contamination and colonization of the upper airways. We report a patient with recurrent aspiration and lipoid pneumonia in whom a confluent culture of Myco. chelonei was obtained from bronchial washings. Although the clinical setting for true pathogenicity was present, subsequent investigations led us to conclude that the organism was a casual mycobacterium.

Adult↗
PubMed1984

A "new" low incidence red cell antigen, NFLD.

A "new" low incidence red cell antigen, NFLD, is described. It was found in a Caucasian family and is inherited as an autosomal dominant. The antigen is not part of the AB0, MNSs, Duffy, Kidd, or Yt blood group systems and probably does not belong to the Rh or Kell blood group systems.

Blood Group Antigens↗
PubMed1984

Maternal responsivity in interactions with handicapped infants.

The present study investigated the influence of 3 infant characteristics on mothers' interactions with their handicapped young children. These 3 characteristics are chronological age, mental age, and handicapping condition. Maternal responsivity was hypothesized to increase with mental and chronological age and to be more closely linked to mental than chronological age. In addition, it was expected that handicapped group membership would be related to maternal behavior, but that many of these effects would be accounted for by mental age. 111 handicapped young children and their mothers were observed in a 15-min free-play session. The children ranged in age from 3 to 36 months of age and were classified as Down's syndrome (N = 56), developmentally delayed (N = 21), or cerebral palsied (N = 34). Maternal responsivity to their infants' behavior was explored for total behavior and for proximal and distal behaviors separately using proportion scores to control for overall levels of infant and maternal behavior exhibited. Infants but not mothers emitted more behavior in the free-play setting as the infants' mental and chronological age increased. As expected, mothers were more responsive proportionately to their infants' behavior as their children became more mature mentally and chronologically older, even after controlling for age-related increases in infant behavior. Since mental and chronological age were related, partial correlational analyses were performed. The age-related increases in maternal responsivity were accounted for by mental but not chronological age. Differences as a function of handicapped group membership also were found. Cerebral palsied infants exhibited less behavior than did the Down's syndrome and developmentally delayed infants. Mothers of developmentally delayed infants exhibited more responsive behavior proportionately than did mothers of the other 2 groups. However, this difference was due to the higher mental age of the infants.

Cerebral Palsy↗
PubMed1984

Age and handicapped group differences in infants' visual attention.

102 handicapped children who ranged in age from 3 to 36 months and who were classified as Down's syndrome, cerebral palsied, developmentally delayed, or multiply handicapped were given a visual attention task. Subjects were presented 6 repeated trials of nonsocial stimuli followed by a seventh novel trial (20-sec trials, 20-sec intertrial intervals). Habituation to the repeated stimulus was assessed by examining fixation trends across the 6 trials. Differences in habituation as a function of chronological age, mental age, and handicapped group membership were examined. Over the entire sample, linear trends were found, as looking time decreased over trials. An age effect was found as the 3-7-month-olds did not exhibit a decrease in fixation over the 6 trials, while the older infants did exhibit response decrement. Parallel mental age differences in response decrement were found. No differences in fixation patterns were found for the 4 handicapped groups. Cluster analyses revealed 3 distinct fixation patterns over the 6 redundant trials, which were characterized by (1) high initial fixation and response decrement, (2) low initial fixation and no response decrement, and (3) moderate initial fixation and monotonic decrease in fixation over trials. Individual differences in cluster membership were found as a function of chronological and mental age but not handicapped group membership.

Attention↗
PubMed1984

Massive mediastinal hematoma caused by a double-lumen subclavian catheter.

Double-lumen subclavian catheters have recently been released for use as a temporary blood access for extracorporeal circulation. Initial reports indicate that once properly inserted, these catheters are safe. However, massive mediastinal hematoma that occurred 3 days after insertion and uneventful initial dialysis with a double-lumen subclavian catheter has been documented. The patient experienced excruciating pain immediately after the onset of the subsequent dialysis and was found to have developed a massive mediastinal hematoma. It appears that at some point after the completion of the initial dialysis, the catheter tip eroded the vein and entered the mediastinum. As a result, the proximal (arterial) perforations were inside the vein, allowing blood to freely enter the circuit and be forcefully pumped into the mediastinum through the distal (venous) perforations near the tip. Prompt recognition of the problem and immediate discontinuation of dialysis prevented a potential fatal outcome in this case.

Adult↗
PubMed1984

Treatment of acute post-infective polyneuropathy by means of plasma exchange.

15 patients with acute post-infective polyneuropathy of the Guillain-Barré type have been treated by means of plasma exchange. The clinical course and outcome of these patients is compared to that in a retrospectively matched control series who were treated with supportive therapy only. All patients had severe rapidly evolving muscle weakness and approximately half the patients in each group required ventilatory assistance. Both the duration of muscle weakness and the hospitalisation time was significantly shorter in the patients treated by means of plasma exchange. These results suggest that plasma exchange is of significant benefit in the treatment of patients with the Guillain-Barré syndrome.

Adolescent↗