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Biomedical subjects

R Weller

Publications and source records attributed to R Weller.

At least 73 records · Page 4Linked to original sources

Onycholysis in a case of atopic eczema treated with PUVA photochemotherapy.

Onycholysis following the ingestion of psoralens and subsequent exposure to natural sunlight has been reported on several occasions and was first reported following photochemotherapy in 1978 by Ortonne and Baran from France and in 1979 by Mackie from Scotland. Mackie commented that she hoped to stimulate further reports of onycholysis induced by PUVA photochemotherapy in order to establish whether or not it was a definite complication of such treatment. Since then, there has been a dearth of similar reports. We describe a patient with severe atopic eczema and alopecia totalis who developed onycholysis of all finger nails and a toe nail during PUVA photochemotherapy.

Adult↗

Uncultivated cyanobacteria, Chloroflexus-like inhabitants, and spirochete-like inhabitants of a hot spring microbial mat.

Analysis of 16S rRNA sequences retrieved as cDNA (16S rcDNA) from the Octopus Spring cyanobacterial mat has permitted phylogenetic characterization of some uncultivated community members, expanding our knowledge or diversity within this microbial community. Two new cyanobacterial 16S rRNA sequences were discovered, raising to four the number of cyanobacterial sequence types known to occur in the mat. None of the sequences found is that of the cultivated thermophilic cyanobacterium Synechococcus lividus. A new 16S rRNA sequence characteristic of green nonsulfur bacteria and their relatives was discovered, raising to two the number of such sequences known to exist in the mat. Both are unique among the 16S rRNA sequences of cultivated members of this group, including an Octopus Spring isolate of Chloroflexus aurantiacus and Heliothrix oregonensis, whose sequences we report herein. Two spirochete-like 16S rRNA sequences were discovered. One can be placed in the leptospira subdivision of the spirochete group, but the other has such a loose affiliation with the spirochete group that it might actually belong to an as yet unrecognized subdivision or even to a new eubacterial line of descent.

Bacteria↗

Intra-thecal treatment of leptomeningeal lymphoma with immunotoxin.

An animal model has been established to investigate the effect of intra-thecal (i.t.) immunotoxins in the treatment of leptomeningeal metastases of acute lymphoblastic leukaemia (ALL). Direct inoculation of L2C lymphoma cells into the cisterna magna of guinea-pigs gives rise to a leptomeningeal pattern of growth, similar to that of human ALL, and to a systemic leukaemia which develops in approximately 14 days. In our model the systemic disease could be controlled with cyclophosphamide while the meningeal disease progressed and provided a target for i.t. immunotoxin. The immunotoxin used consisted of an anti-idiotypic antibody disulphide-bonded to the ribosome-inactivating protein saporin. It was highly cytotoxic to L2C cells in vitro, being around 30,000 times more potent than a control immunotoxin at inhibiting protein synthesis. In vivo, the maximum tolerated dose of i.t. immunotoxin was 10 micrograms. From the rate at which radiolabelled immunotoxins appeared in the plasma following i.t. injection, we were able to estimate that its half-life in the cerebrospinal fluid (CSF) was between 1 1/2 and 2 hr. Intrathecal treatment of guinea-pigs with immunotoxin 1 day after inoculation of L2C cells into the cisterna magna had a remarkable therapeutic effect. All guinea-pigs treated with 0.5 or 5 micrograms of immunotoxin survived, and remained tumour-free for more than 100 days after treatment, while control animals given cyclophosphamide alone or an irrelevant immunotoxin had a mean survival time of 28 days. Provided concerns over toxicity can be overcome, these results indicate that i.t. immunotoxins offer an alternative, highly specific form of treatment in leptomeningeal neoplasia.

Animals↗

Reproducibility of quantitative hexakis-2-methoxyisobutylisonitrile single photon emission tomography in stable coronary artery disease.

The quantification of myocardial perfusion abnormalities is necessary to allow comparison of repeated studies, especially in the evaluation of the success of medical, interventional or combined treatment in stable coronary artery disease or in evolving myocardial infarction. The purpose of this study was to assess inter-observer reproducibility of tomographic study processing using a semi-automatic quantitative programme. Technetium 99m hexakis-2-methoxyisobutylisonitrile (99mTc-Sestamibi) was chosen for tomographic imaging of repeated rest-stress studies in patients with stable coronary artery disease. The quantification was performed using a modification of the Cedars polar coding and comparison with the normal data base. The perfusion defects were quantified separately for each standard perfusion area [left anterior descending (LAD), right coronary (RCA) and left circumflex (LCX) arteries] and total area of hypoperfused myocardium. The inter-observer variability for 40 tomographic studies was accomplished. The defects were the largest in the LAD perfusion area (average 19.7% of the normalized LAD supply area) with an inter-observer correlation of 0.84 for this region. The greatest variability was found for the LCX region (r = 0.55) and is attributed to a small average perfusion defect (7.1%), only 18 studies having abnormal perfusion in this area. In total, an average 14.3% of the left ventricular myocardium was significantly hypoperfused, and the inter-observer correlation was 0.87. These results show good inter-observer reproducibility using semi-automatic quantitation of perfusion defects. Careful interpretation of smaller defects in the evaluation of treatment results is advised when repeated 99mTc-Sestamibi single photon emission tomography studies are processed by more than one observer.

Coronary Disease↗

Upward creep of the heart in exercise thallium 201 single photon emission tomography: clinical relevance and a simple correction method.

The upward creep of the heart during myocardial single photon emission tomography (SPET) acquisition has been reported as a frequent source of false-positive results. The aim of this study was to simplify the detection and correction of this upward creep and to estimate its clinical relevance during routine patient care. To recognize the upward heart motion a straight line was fitted to the upper and lower border of consecutively displayed tomographic projection images. In this way, vertical translation of at least 1 pixel in size could be detected easily. On the assumption of a slow but continuous upward motion a fast interpolation correction method was developed. From 100 consecutive, supine, ergometric exercise studies, 1, 2 or 3 pixels of upward creep were found in 16, 4 or 3 patients, respectively. It was found that an upward creep of at least 2 pixels (7/100 cases) led to evident, mostly antero-septal defects on quantitative bull's-eyes, whereas only upward creeps of 3 pixels or more (3/100 cases) produced false-positive diagnostic results. The simple correction method offered a sufficient compensation of image and/or bull's-eye artefacts. These clinical findings could be reproduced in a computer model. Thus, it can be stated that clinically significant upward creep of the heart during stress SPET acquisition is relatively rare; it may have been overestimated in the past, and its artificial effects can be corrected by a quick and simple algorithm.

Algorithms↗

Comparison of epidural and patient-controlled intravenous morphine following joint replacement surgery.

The authors conducted a randomized, prospective study comparing epidural morphine with patient-controlled intravenous (iv) morphine in 30 patients recovering from total hip or total knee arthroplasty. Six, 18, and 24 hr postoperatively, patients used a 10 cm visual-analogue scale to indicate both their current degree of discomfort and the maximum discomfort they had experienced since the previous evaluation. Pain at the time of evaluation did not differ between patients receiving epidural (2.6 +/- 0.4 cm, mean +/- SEM) and patient-controlled iv morphine (3.4 +/- 0.3 cm). However, patients who received epidural morphine recalled less pain during the period preceding evaluation (4.2 +/- 0.5 cm) than did those receiving patient-controlled analgesia (5.5 +/- 0.4 cm, P less than 0.05). Patients receiving epidural morphine were more likely to require treatment for pruritus (4 of 15) than patients who received patient-controlled iv morphine (none of 15, P less than 0.05). Minimum respiratory rates were lower in patients receiving epidural morphine (15.0 +/- 0.3) than in those receiving patient-controlled analgesia (16.5 +/- 0.4, P less than 0.05), but no patients required treatment for respiratory depression. The authors conclude that epidural morphine may provide more consistent analgesia following joint replacement surgery than patient-controlled morphine; however, there is a higher incidence of side-effects with the epidural technique.

Adult↗

Treatment of experimental murine Coxsackie B3 myocarditis.

Using the murine model of coxsackievirus B3-induced myocarditis we studied the effects of various immunosuppressive agents on the course and outcome of the disease in genetically different strains of mice. The response to drug treatment varied greatly among the strains of inbred mice, which suggests different immune pathomechanisms operative in mediating myocarditis.

Animals↗

16S rRNA sequences of uncultivated hot spring cyanobacterial mat inhabitants retrieved as randomly primed cDNA.

Cloning and analysis of cDNAs synthesized from rRNAs is one approach to assess the species composition of natural microbial communities. In some earlier attempts to synthesize cDNA from 16S rRNA (16S rcDNA) from the Octopus Spring cyanobacterial mat, a dominance of short 16S rcDNAs was observed, which appear to have originated only from certain organisms. Priming of cDNA synthesis from small ribosomal subunit RNA with random deoxyhexanucleotides can retrieve longer sequences, more suitable for phylogenetic analysis. Here we report the retrieval of 16S rRNA sequences from three formerly uncultured community members. One sequence type, which was retrieved three times from a total of five sequences analyzed, can be placed in the cyanobacterial phylum. A second sequence type is related to 16S rRNAs from green nonsulfur bacteria. The third sequence type may represent a novel phylogenetic type.

Base Sequence↗

16S rRNA sequences reveal numerous uncultured microorganisms in a natural community.

Microbiologists have been constrained in their efforts to describe the compositions of natural microbial communities using traditional methods. Few microorganisms have sufficiently distinctive morphology to be recognized by microscopy. Culture-dependent methods are biased, as a microorganism can be cultivated only after its physiological niche is perceived and duplicated experimentally. It is therefore widely believed that fewer than 20% of the extant microorganisms have been discovered, and that culture methods are inadequate for studying microbial community composition. In view of the physiological and phylogenetic diversity among microorganisms, speculation that 80% or more of microbes remain undiscovered raises the question of how well we know the Earth's biota and its biochemical potential. We have performed a culture-independent analysis of the composition of a well-studied hot spring microbial community, using a common but distinctive cellular component, 16S ribosomal RNA. Our results confirm speculations about the diversity of uncultured microorganisms it contains.

Base Sequence↗

The orthopan tomoscintigram--a new application of emission computed tomography for facial bone scanning.

The exact regional correlation of findings of facial bone scans, planar or SPECT, to dental orthopan X-ray films (OPT) is difficult because of the very different projection techniques. To improve correlative imaging in this regard a projection algorithm was developed that uses SPECT data of the skull for reconstructing an orthopan tomoscintigraphic projection. Fourteen conventional SPECT slices of the upper and lower jaws were obtained during bone scanning. All mandibular slices were superimposed resulting in a horseshoe shaped structure, while was marked by an ROI which was divided into segments. All 14 SPECT slices were then masked by this segmental ROI, thereby marking the teeth-carrying bone in all slices. The information from this horseshoe like ROI is then transformed into lines. Line by line arrangement results in an orthopan projection, the orthopan tomoscintigram. This new display allows 1:1 true scale superimposition with the X-ray OPT and markedly facilitates correlative imaging.

Facial Bones↗

16S rRNA sequences reveal uncultured inhabitants of a well-studied thermal community.

Molecular methods are beginning to reveal inhabitants of natural microbial communities which have never before been cultured. Our approach involves selective cloning of naturally occurring 16S rRNA sequences as cDNA, and comparison of these sequences to a database which includes 16S rRNA sequences of isolated community members. We provide here an overview of the method and its potential for community analysis. A 16S rRNA sequence retrieved from the well-studied hot spring cyanobacterial mat in Octopus Spring (Yellowstone National Park) is shown as an example of one contributed by an uncultured member of the community.

Base Sequence↗

[Localization of premature and ectopic ventricular depolarization using a new nuclear medicine tomographic technique].

In planar radionuclide ventriculography (RNV) identification of the site of initial contraction is possibly by the Fourier phase. First clinical experiences will be presented with a new integrated tomographic technique--ISPECT--in noninvasively assessing the site of ectopic or premature ventricular depolarization. In six patients Fourier phases of RNV and ISPECT were performed and compared in five with results from the corresponding electrophysiologic study. It was possible to exactly localize the beginning of mechanical contraction in the two orthogonal planes: during pacemaker stimulation at the apex of the right ventricle, at the lateral border of a large aneurysm during ventricular tachycardia, and at the site of three of five WPW bundles. In the other two bundles the site of first contraction was near the area found during invasive mapping procedure. Thus, this new ISPECT approach together with planar radionuclide imaging may help in noninvasively localizing the site of ectopic and premature depolarization in addition to surface ECG.

Adult↗

The effect of concomitant disorders in childhood depression on predicting treatment response.

Children with pure depression or depression plus an anxiety-related disorder (n = 14) had a higher drug response rate (57%) and a lower placebo response rate (20%) when compared to children with depression plus a concomitant conduct or oppositional disorder (n = 17) (33% drug response rate and 67% placebo response rate). These findings could explain why studies of prepubertal-onset depression found no differences between drug and placebo treatment assuming that a large percentage of the studies' subjects had concomitant conduct or oppositional disorders. The children with pure depression or depression plus an anxiety-related disorder had different symptom clusters from those with depression plus a concomitant conduct or oppositional disorder. The former had more severe CDRS ratings on sleep, appetite disturbance, depressed feelings, and psychomotor retardation. In contrast, those with a concomitant conduct or oppositional disorder had shorter attention spans and were more likely to disturb other children (based on Conners scale scores).

Child↗

[The effect of 3-dimensional data stabilization in radionuclide ventriculography on the statistical numerical error in the ejection fraction].

The suitability of a 3-dimensional filter in diminishing the statistical noise of left ventricular volume curves without any systematical error in the left ventricular ejection fraction (EF) was investigated. The EF values were compared in 50 studies on 24 patients. There was no significant systematical difference between the EFs before and after filtering. The filter diminishes the statistical uncertainty of the EF by a factor of 0.47. Therefore, the method may possibly be employed in processing the left ventricular volume curves.

Adult↗

The contraction fraction (CF) in myocardial studies with technetium-99m-isonitrile (MIBI)--correlations with radionuclide ventriculography and infarct size measured by SPECT.

Criteria for the detection of coronary artery disease in nuclear cardiology include visualization of perfusion defects and functional impairment of contraction. The purpose of this study is to combine both methods in one procedure with the new myocardial perfusion tracer, 99mTc-methoxy-isobutyl-isonitril (MIBI), reducing time and radiation burden to the patient. Following an uncomplicated recovery, ten patients with first myocardial infarction participated in this study. Radionuclide ventriculography (RNV) was performed at rest and during exercise. Within 2-3 days, 370 MBq 99mTc-MIBI were injected and SPECT acquisition commenced 1 h later. Data processing included a scar image in polar coordinates. Areas of significantly reduced tracer uptake were expressed as a percentage of the total myocardial area. Directly following SPECT, resting and maximum exercise gated planar LAO images were recorded and the contraction was quantified. The concept of the contraction fraction (CF) rested on the end systolic change in count distribution: their increase in density and their centripetal concentration. For comparison, geometrical inner edge detection techniques were also applied. All algorithms for describing an EF equivalent were verified by computer simulations, showing a perfect correlation over a wide range of preset EFs. When applied to the patient studies only the non geometric methods revealed a good correlation with the ejection fraction (EF) obtained by RNV, and with the infarct size measured by SPECT.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗

Selective Recovery of 16S rRNA Sequences from Natural Microbial Communities in the Form of cDNA.

Cloning of cDNA obtained from 16S rRNA (16S rcDNA) selectively retrieves species-specific sequence information useful for analyzing the composition and structure of natural microbial communities. With this technique we obtained recombinant 16S rcDNA libraries from Escherichia coli and from a model hot-spring cyanobacterial-mat community. The recombinant plasmids contained exclusively 16S rRNA-derived inserts. This selective approach is independent of biasing culture techniques and eliminates the laborious screening required to locate 16S rRNA gene-bearing recombinants in genomic DNA libraries obtained from natural communities.

Journal Article↗

A descriptive profile of the depressed child.

We have identified a number of basic descriptive features common to the prepubertal child (aged 6-12) who meets criteria for an objectively defined mood disorder in the inpatient psychiatric setting. Clinical and structured diagnostic interviews conducted with both the child and the parent revealed that DSM-III criteria for major adult mood disorders were easily met by the depressed children. The symptom profile for the child is similar to the adult profile: feelings of hopelessness, sadness, and despair; depressed mood; vegetative symptoms of low energy, appetite loss, and disturbed sleep; and quite frequently suicidal ideation and/or action. Noteworthy is the fact that most of the parents did not bring their children to the setting reporting that they (either themselves or the child) were depressed. The parent was most likely to focus on the change in school performance and on relationships with siblings or other family members (withdrawal, more fighting and irritability, anhedonia, etc.). In sum, our findings indicate that children with MDD tend to have family histories of psychiatric disorder, school problems, and psychosocial adjustment problems. We have also found IMI to be effective in treating the disorder (e.g., Hughes & Preskorn 1989; Preskorn et al. 1982, 1986, 1987). Thus, early diagnosis and effective treatment are possible. This conclusion raises the possibility that steps can be taken to prevent (or at least interrupt) the long-term sequelae (e.g., chronic dysthymia, impaired self-image, impaired psychosocial adjustment) of untreated depressive episodes in prepubertal children.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗