Biomedical subjects

S Pasternak

Publications and source records attributed to S Pasternak.

16 recordsLinked to original sources

PubMed2004

XMCD under pressure at the Fe K edge on the energy-dispersive beamline of the ESRF.

The present paper demonstrates the feasibility of X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) at high pressure at the Fe K edge on the ID24 energy-dispersive beamline of the ESRF. In 3d transition metals, performing experiments at the hard X-ray K edge rather than at the magnetically interesting soft X-ray L edges represents the only way to access the high-pressure regime obtainable with diamond anvil cells. The simultaneous availability of a local structure (XAS) and of a magnetic (XMCD) probe on the sample under identical thermodynamical conditions is essential for studying correlations between local structural and magnetic properties. The state-of-the-art theoretical understanding of K-edge XMCD data is briefly summarized, and the set-up of beamline ID24 for high-pressure XMCD experiments is illustrated and the conditions required to perform measurements at the K edges of 3d transition metals are underlined. Finally, two examples of recent high-pressure results at the Fe K edge in pure Fe and Fe3O4 powder are presented.

Journal Article↗

PubMed2001

Exfoliation syndrome: clinical and genetic features.

We have ascertained a large number of individuals and families with exfoliation syndrome in order to clarify the disorder's mode of inheritance. Patients with exfoliation syndrome and their relatives were recruited from the practices of a group of ophthalmologists in Maritime Canada. The degree to which the subjects were affected was graded according to a standardized 1-4-point clinical scheme. Pedigrees were constructed from information supplied by family members and from genealogical sources. A total of 782 patients and relatives participated, of whom 467 were definitely affected. The mean age of affected males and females did not differ significantly, but females appeared to be more severely affected at ascertainment than males. More than half of the affected subjects had definite exfoliation in only one eye. Approximately 30 multiplex families were discovered, including one containing 23 affected members among a total of 137 examined individuals that constitutes the largest exfoliative pedigree thus far described. We observed well-documented paternal transmission of the trait, a finding that has not to our knowledge been previously reported. Clustering of cases in the families provides evidence for the involvement of genetic factors. The possibility of homozygosity is suggested in a few patients by the earlier or more frequent presentation of the disorder in the offspring of two affected parents or consanguineous pairings. Although a multifactorial mode of inheritance cannot be excluded, exfoliation syndrome appears to be inherited as an autosomal dominant trait whose late onset and incomplete penetrance poses a significant but not insuperable obstacle to pedigree construction.

Aged↗

PubMed2000

Doctor-patient concordance and patient initiative during episodes of low back pain.

Doctor-patient concordance and patient initiative were examined in a prospective network interview study, with telephone follow-up, of a cohort of 100 patients presenting with low back pain to their family physician. The average overall rate of concordance was 60% (95% CI = 53 to 66), with the highest rates for radiographic imaging studies and sick leave. No correlation was found between concordance and patient parameters. Subjects initiated an average of two (95% CI = 1.7 to 2.3) diagnostic or therapeutic procedures, the most common of which were for medications (40%), followed by bed rest (26%) and back school (22%). One out of every six subjects initiated a referral to a complementary therapist. Positive correlation was found between patient initiatives and pain severity (P = 0.022) and disability (P = 0.02). There was a negative correlation between the subjects' initiatives and their belief that the physician understood the cause of their pain and its influence on their life (P = 0.02). Overall, those patients who described more pain or disability sought more types of diagnostic and therapeutic measures, while those who felt they had been understood sought less.

Cohort Studies↗

PubMed1998

[Compliance with treatment of low back pain].

Explore the source record for details and available documents.

Humans↗

PubMed1996

Enchondroma of the orbit.

PURPOSE: To report a documented case of orbital enchondroma. METHODS: A 25-year-old woman had an asymptomatic orbital mass. Computed tomographic scan was performed. The mass was surgically removed from the medial wall of the orbit, and the specimen was submitted for histopathologic examination. RESULTS: The tumor showed typical radiologic and histopathologic appearance of an enchondroma with typical hypocellular lobules of cartilage enclosed by lamellar bone. CONCLUSION: Cartilaginous neoplasms in the orbit are extremely rare.

Adult↗

PubMed1996

Monoclonal origin of localised orbital amyloidosis detected by molecular analysis.

AIMS: Primary localised orbital amyloidosis is a rare disease. The purpose of this study was to describe two cases of primary orbital amyloidosis and emphasise the value of molecular analysis of immunoglobulin gene rearrangement in identifying a monoclonal population of cells responsible for the amyloid production. METHODS: Charts and biopsy specimens of each case were reviewed. Conventional light microscopy, immunohistochemistry, and polymerase chain reaction (PCR) analysis for immunoglobulin gene rearrangement were performed in both cases. RESULTS: An unusual presentation of localised primary amyloidosis with bilateral and extensive enlargement of multiple extraocular muscles was seen in case 1. The presence of amyloid deposits was confirmed by biopsy in both cases. Evidence of a monoclonal population of plasma cells was shown by immunohistochemical analysis in case 2 only. The monoclonal origin of the cells responsible for the amyloid deposition was determined by PCR analysis demonstrating immunoglobulin heavy chain gene rearrangement in both cases. CONCLUSIONS: A monoclonal population of plasma cells responsible for the amyloid deposition was present in these two cases. PCR analysis is extremely helpful in determining monoclonality, a finding that may have important therapeutic and prognostic implications.

Adult↗

PubMed1987

The Memorial Pain Assessment Card. A valid instrument for the evaluation of cancer pain.

Effective evaluation and treatment of cancer pain require valid and independent measurement of pain intensity, pain relief, and psychological distress. The Memorial Pain Assessment Card (MPAC) is a simple instrument designed to provide rapid evaluation of these subjective experiences. On the 8.5 by 11 inch card are printed the eight pain intensity descriptors, and three visual analog scales which measure pain intensity, pain relief, and mood. Experienced patients can complete it in less than 20 seconds. The authors administered the MPAC to 50 hospitalized cancer patients within 48 hours of referral to the Pain Service for inadequate pain control, together with standard measures: The McGill Pain Questionnaire, Profile of Mood States, Hamilton Depression Scale, and Zung Anxiety Scale. Correlational and multiple regression analyses revealed that the MPAC can distinguish pain intensity from pain relief and from general psychological distress, and it can provide multidimensional assessment that is practically equivalent to the full assessment battery. We conclude that the MPAC is valid and effective for clinical use, and recommend it for the assessment of individual patients, and as an outcome measure in clinical trials.

Adolescent↗

PubMed1987

A clinical trial using syrup of ipecac and activated charcoal concurrently.

A prospective study was conducted to determine if the emetic effects of syrup of ipecac are preserved when activated charcoal is administered prior to emesis. Ten overdose patients who fulfilled the entrance criteria for the study were administered 60 mL syrup of ipecac by a nasogastric tube followed immediately by 500 mL of tap water. Ten minutes after the ipecac was administered, an aqueous slurry of 50 g activated charcoal diluted to 500 mL was instilled down the nasogastric tube and the tube was removed. Emetic response and time to emesis were recorded. Thirty minutes after emesis subsided, a second dose of 50 g activated charcoal (with sorbitol) was administered orally. Emetic responses were noted in all ten patients. The patients averaged 3.7 emetic episodes. Emesis commenced in an average of 13.8 minutes from the start of ipecac administration and concluded in an average of 45.9 minutes. These results in patients are similar to those observed in a previously reported volunteer group similarly treated. This protocol allows early administration of activated charcoal while preserving the emetic properties of syrup of ipecac in the patients treated.

Adolescent↗

PubMed1986

Preserving the emetic effect of syrup of ipecac with concurrent activated charcoal administration: a preliminary study.

Activated charcoal is reported to block the emetic effect of syrup of ipecac. Therefore, activated charcoal administration is commonly delayed until syrup of ipecac induced emesis is complete. The advantages of early administration of activated charcoal have been well documented. Preservation of the emetic effect of syrup of ipecac in the presence of activated charcoal may produce a synergistic effect by enhancing toxin elimination. A study was conducted in ten human volunteers to determine if activated charcoal prevents the emetic effect of syrup of ipecac when a temporal separation exists between administration of the two substances. Syrup of ipecac 60 ml plus water 480 ml was administered via an 18 French nasogastric tube followed by an aqueous slurry of activated charcoal 50 g five minutes later. Eight (80%) of the subjects had emesis in a mean time of 20.25 minutes (range 16-26 min). The total dose of activated charcoal was retained for a mean time of 6.75 minutes (range 0-17 min). Two subjects (20%) failed to have emesis. This study illustrates that activated charcoal may not completely block the emetic effect of syrup of ipecac.

Adult↗

PubMed1979