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Biomedical subjects

A Stein

Publications and source records attributed to A Stein.

At least 19 recordsLinked to original sources
PubMed1992

Introns of the chicken ovalbumin gene promote nucleosome alignment in vitro.

A defined in vitro chromatin assembly system was used to examine the nucleosome alignment induced by histone H5 throughout a 12 kilobase pair chicken genomic DNA fragment containing the ovalbumin gene. In contrast with total fragmented chicken DNA and several anonymous cloned fragments, much of the gene permitted histone H5 to space nucleosomes at physiological intervals in an extended array. Nucleosomes at the 3'-end of the gene and on approximately 4 kilobase pairs of 5'-flanking ovalbumin sequence did not become aligned to appreciable extents. Analysis of cloned 2-3 kilobase pair subfragments suggested that a strong nucleosome alignment signal, specifying a 196 +/- 5 base pair repeat exists in intron E. A second discrete region of the gene, which mapped approximately to intron A, exhibited nucleosome alignment with a spacing periodicity of about 200 base pairs. The ovalbumin cDNA did not permit nucleosome alignment. These findings suggest that some of the introns contain signals that direct nucleosome alignment over the ovalbumin gene in a way conducive to its regulation.

Animals↗
PubMed1992

High-dose chemoradiotherapy followed by autologous bone marrow transplantation as consolidation therapy during first complete remission in adult patients with poor-risk aggressive lymphoma: a pilot study.

Twenty consecutive patients with poor-risk aggressive lymphoma who at presentation either had elevated serum lactic dehydrogenase level (LDH) and any one of the other poor-prognostic features: bulky mass greater than or equal to 10 cm, advanced stage III or IV, and greater than or equal to 2 extranodal sites, or normal LDH level and all other three features, underwent high-dose chemo/radiotherapy followed by unmanipulated autologous bone marrow transplantation (BMT) during their first complete remission. Eighteen had B-cell lymphoma and 2 had T-cell lymphoma. Eleven patients had high-grade (7 immunoblastic, 3 small noncleaved, non-Burkitt's, and 1 Burkitt's) and 9 had diffuse large cell lymphoma. All patients had achieved a complete remission following conventional chemotherapy. Four patients had also received involved field radiotherapy to areas of bulky disease. The preparative regimen consisted of high-dose etoposide 60 mg/kg and cyclophosphamide 100 mg/kg in combination with fractionated total body irradiation (FTBI) 1,200 cGy (15 patients), or single-dose TBI 750 cGy (2 patients), or carmustine 450 mg/m2 (3 patients). All patients tolerated the treatment well and achieved complete hematologic recovery. Three patients have relapsed at days 79, 196, and 401 after transplantation. Seventeen patients (84%) are alive and relapse-free with a median follow-up of 34 months (range 2 to 54). We conclude that high-dose chemo/radiotherapy followed by autologous BMT can be given as consolidation therapy during first remission in these patients with minimal transplant-related toxicity.

Adult↗
PubMed1992

Adjuvant radiotherapy in patients post-radical prostatectomy with tumor extending through capsule or positive seminal vesicles.

Between 1976 and 1989, 115 patients at UCLA had radical retropubic prostatectomy for clinically localized prostate cancer with positive surgical margins, penetration of tumor into or through the capsule, or positive seminal vesicles. Twenty-four of those received adjuvant radiotherapy after having recovered from surgery. Complications of adjuvant treatment were uncommon and included urethral strictures in 3 patients and transient leg edema in 1. No patient in this group has had proved clinical disease progression though 6 have isolated detectable serum prostate-specific antigen (PSA) values. Clinical disease-free survival at five and seven years was 92 percent. If detectable PSA is also considered as evidence of tumor recurrence, the corresponding disease-free survival rates were 75 percent at five years and 54 percent at seven years. The 91 patients who received no postoperative radiotherapy had a clinical disease-free survival of 67 percent at five years and 56 percent at seven years. Disease-free survival drops to 43 percent and 24 percent, respectively, if detectable follow-up PSA is considered an indicator of disease progression. The comparisons of the survivorship curves in this retrospective study for the two treatment groups are statistically significant both for disease-free survival (p = 0.041), and disease-free survival with undetectable PSA (p = 0.043). Adjuvant radiotherapy has a beneficial effect after radical prostatectomy in patients with local tumor extension.

Aged↗
PubMed1992

Salvage radical prostatectomy after failure of curative radiotherapy for adenocarcinoma of prostate.

Radical prostatectomy with curative intent was performed in 13 patients with prostate cancer after local failure of radiotherapy. Of these patients, 2 underwent cystoprostatectomy for bladder neck involvement by the prostatic tumor. Local recurrence had been diagnosed twenty-one to one hundred sixty-eight months (mean 65.4 months) after completion of radiotherapy (6,000-7,000 cGy; mean 6,136 cGy). Three patients had radioactive implants. Rising prostate-specific antigen (PSA) was part of the indication for surgery in 5 patients. Complications included minor rectal injury (1 patient) and total incontinence (2/13 patients). Two patients had positive surgical margins and 6/13 patients had involvement of seminal vesicles, 2 of whom also had positive lymph nodes. The authors conclude that salvage prostatectomy is feasible after radiation failure. Transrectal ultrasound and careful monitoring of PSA after irradiation treatment may improve patient selection and minimize the risk of complications and incomplete excision.

Adenocarcinoma↗
PubMed1992

Prostate specific antigen levels after radical prostatectomy in patients with organ confined and locally extensive prostate cancer.

A total of 230 patients with localized prostate cancer underwent radical retropubic prostatectomy at UCLA (pathological stage T1-3 N0, M0). Classification into groups included 115 patients with organ confined disease (group 1), 82 with invasion into or through the capsule (group 2) and 33 with seminal vesicle involvement (group 3). Median followup was 48 months. The 10-year, cause-specific survival was 96%, 90% and 63%, and 5-year, clinical, disease-free survival was 91%, 79% and 58% for the 3 groups, respectively. Recent prostate specific antigen (PSA) levels were measured in most patients, even those operated upon many years ago. Of the patients 41 had detectable (0.4 ng./ml. or greater) PSA levels without any other clinical evidence of progression and 15 with clinical evidence of progression had PSA levels in the detectable range at the time of clinical progression. When isolated detectable PSA was also considered an indicator of progression the 5-year and 10-year, disease-free rates were 61% and 41%, respectively. These data show that radical prostatectomy performed in patients with even microscopic invasion into the capsule, positive margins and seminal vesicle involvement is associated with a higher clinical progression rate than organ confined disease. If isolated detectable PSA is also considered an indicator of recurrence the disease-free survival after radical prostatectomy might be less than indicated by previous studies. The relationship among survival, local tumor extension and PSA must be carefully examined.

Adult↗
PubMed1992

Detection of local recurrence after radical prostatectomy by prostate specific antigen and transrectal ultrasound.

Twenty patients with detectable levels of prostate specific antigen (PSA) after radical prostatectomy with no identifiable distant metastases were evaluated for local recurrence by digital rectal examination and transrectal ultrasound combined with biopsies. Of the patients 9 (45%) were found to have histological evidence of local recurrence at the initial assessment. All 4 patients with an abnormal digital rectal examination had recurrent disease. Transrectal ultrasound displayed abnormalities in 12 of the 20 patients, 7 of whom had positive biopsies. Random biopsies of the vesicourethral junction were performed in 8 patients who had negative ultrasound findings and an unremarkable digital rectal examination, of whom 2 had histological documentation of local recurrence. Complications occurred in 1 patient (5%) who presented with clot retention. We conclude that PSA is an excellent tool for identification of recurrent disease after radical prostatectomy, and transrectal ultrasound guided biopsy is a useful diagnostic approach in patients suspected of local failure, especially when the digital rectal examination is unremarkable.

Antigens, Neoplasm↗
PubMed1992

Esophageal dysmotility as a serendipitous observation on ventilation-perfusion imaging of the lungs.

Tc-99m DTPA aerosol is often swallowed during inhalation for lung ventilation scans. The authors evaluated a 16-year-old girl with a known history of mixed collagen disorder (positive lupus anticoagulants) for symptoms of cough and acute shortness of breath. Tc-99m DTPA accumulated in the distal esophagus during aerosol inhalation and remained there at the end of the perfusion study, a period of approximately 1 hour. This serendipitous observation antedates clinical signs and symptoms of dysphagia.

Adolescent↗
PubMed1992

Psychosocial adjustment in siblings of children with chronic life-threatening illness: a research note.

The psychosocial functioning of 10 siblings of children with chronic life-threatening illness and their parents was compared with 10 healthy matched controls. The main differences found were in family relationships, with the index siblings expressing more negative emotion in relation to their fathers than controls, index mothers being less involved in social activities and index fathers being less involved with the extended family. No significant differences were found in any of the measures of depression, anxiety and self concept. Index siblings expressed a number of other concerns such as a fear of the break up of their family after the sick child died. The need for increased awareness of the welfare of healthy siblings as well as closer involvement of the fathers is discussed.

Adolescent↗
PubMed1992

Detection of Coxiella burnetti by DNA amplification using polymerase chain reaction.

The polymerase chain reaction (PCR) was used for the detection of Coxiella burnetti, an obligate intracellular bacterium and the etiologic agent of Q fever. A pair of primers derived from the C. burnetii superoxide dismutase gene served to amplify a targeted 257-bp fragment of genomic DNA. These primers were chosen on the basis of GenBank analysis, G + C ratio, and absence of secondary structure. This technique allowed the detection of as few as 10 C. burnetii organisms. C. burnetti was detected in tissue culture and in specimens from patients (heart valves). In all, 8 reference isolates and 22 new isolates of C. burnetii from France were successfully amplified. No amplification products were found when PCR was performed with 25 bacterial species that had been isolated in a clinical laboratory from patients with clinically similar infections. Amplification products of C. burnetii were confirmed by restriction enzyme digestion and dot blot hybridization. The method used here, a combination of PCR and restriction analysis, is a faster and more sensitive assay for C. burnetii than standard culture techniques.

Base Sequence↗
PubMed1992

Phenotypic and genotypic heterogeneity of 8 new human Coxiella burnetti isolates.

Eight new strains of Coxiella burnetii were isolated from chronic Q fever patients using centrifugationashell vial technique. Seven patients had endocarditis (including one patient with an immunodeficiency syndrome), and one had a vascular prosthesis infection. Three prototype strains, Nine Mile phase II, Q212 and Priscilla and eight new isolates were cultured in L 929 cells. Heterogeneity of their cytopathic effect was observed. DNAs of the eleven strains have been isolated and purified by standard procedures. Plasmid DNA was separated from chromosomal DNA by a low melting point gel. Electrophoresis in agarose gel showed that seven of the eight new strains had plasmids which were about 40 kb (plasmid V517 was used as size marker). Endonuclease-restriction analysis of the 8 human isolates is currently under investigation.

Cells, Cultured↗
PubMed1992

Acute effect of consumption/omission of breakfast on exercise tolerance in adolescents.

The purpose of this study was to determine the acute effects of the consumption or omission of breakfast on exercise tolerance in adolescents. Physically active adolescents (14 males and 21 females) were randomly assigned to receive a breakfast (B) or placebo (P) after an overnight fast. Exercise tolerance tests were done 1.5 hours (test 1) and again 4 hours (test 2) after consuming B or P and consisted of cycling on a stationary bike for 4 minutes at each of four consecutive power settings: 25, 50, 75, and 100 watts. Blood glucose and beta-hydroxybutyrate concentrations were measured before both tests. VO2 and VCO2 were measured during minute 3 of cycling at loads 50 and 75 watts and were used to compute the respiratory exchange ratio (RER). Heart rates (HR) were monitored throughout the test and ratings of perceived exertion (RPE) were made at the end of each 4 min interval. Repeated measures ANOVA revealed that there were no differences in RPE; however, differences for HR and RER did exist. Mean RER values were higher for the males receiving B vs males receiving P during test 1. For females, HR were higher for P compared B, and beta-hydroxybutyrate was significantly elevated for P before test 2. The data suggest that exercise tolerance as indicated by the ratings of perceived exertion are unaffected by prior ingestion of a breakfast but breakfast does affect the physiologic responses to exercise.

Adolescent↗
PubMed1991

Chromatin assembly on plasmid DNA in vitro. Apparent spreading of nucleosome alignment from one region of pBR327 by histone H5.

We have found that histone H5 (or H1) induces physiological nucleosome spacings and extensive ordering on some plasmid constructions, but not on others, in a fully defined in vitro system. Plasmid pBR327 containing DNA insertions with lengths close to 300 base-pairs permitted histone H5 to induce a remarkable degree of nucleosome alignment. Seventeen multiples of a unit 210(+/- 4) base-pair repeat, covering the entire plasmid, were detected. Plasmid pBR327, not containing a DNA insert, permitted continuous alignment of only a few nucleosomes. These observations suggest that a necessary requirement in this system for histone H5 (or H1)-induced nucleosome alignment on small (less than 4 kb; 1 kb = 10(3) bases or base-pairs) circular plasmids may be that the total DNA length must be close to an integer multiple of the nucleosome repeat length generated, a type of boundary effect. Consistent with this hypothesis, five deletion constructs of pBR327 (not containing inserts), that spanned 64% of the plasmid, and possessed DNA lengths close to integer multiples of 210 base-pairs, permitted nucleosome alignment by histone H5. We have also found that plasmid length adjustment is not a sufficient condition for nucleosome alignment. For example, plasmids pBR322 and pUC18 did not permit nucleosome alignment when adjusted to near-integer multiples of 210 base-pairs. Also, for pBR327 that contained a length-adjusted deletion in one particular region, appreciable nucleosome alignment no longer occurred. These data suggest that a contiguous approximately 800 base-pair region of pBR327, interrupted in pBR322 and not present in pUC18, can nucleate histone H5-induced nucleosome alignment, which can then spread to adjacent chromatin. Supporting this idea, a positioned five-nucleosome array appears to originate in the required region. Additionally, on a larger (6.9 kb) plasmid construction, the "chromatin organizing region" of pBR327 and adjacent DNA on one side of it exhibited preferred H5-induced nucleosome alignment.

Animals↗
PubMed1991

[Diagnosis of glaucoma using fundus spectrometry in areas outside the papilla].

As a result of the statistical evaluation of spectra on the basis of discriminant analysis, it can be stated that spectrometric measurements on fundus areas are suited for glaucoma diagnosis also outside the papilla. For early recognition of glaucoma, measurements of the papillomacular bundle are more sensitive than measurements in the parapapillary region. Late stages of glaucoma and normal findings are most reliably separated by measurements in the parapapillary region. With increasing severity of the glaucoma, the spectrum of the macular pigment can be demonstrated in the papillomacular bundle. A spectrometrically recognizable lack of erythrocytes documents an impaired retinal microcirculation.

Adolescent↗
PubMed1991

Prostatic specific antigen related to clinical status 1 to 14 years after radical retropubic prostatectomy.

Serum prostatic specific antigen (PSA by Tandem-R immunoassay) was measured in 190 patients after radical prostatectomy for prostate cancer. Serial measurements were made in all patients operated on in the past 3 years; 131 had undetectable levels and 59 had levels in the detectable range. Only 10% of the patients with undetectable PSA following surgery had seminal vesical involvement or positive lymph nodes. None of the patients with undetectable PSA have had clinical recurrence within the 41 months of mean follow-up. In 14 patients who had PSA serially measured since surgery, detectable levels were found within 6 months of operation and 7 of these patients had clinical progression within 2 years; 39 patients had detectable PSA after radical prostatectomy with no clinical evidence of recurrence. Biopsy of the anastomosis was performed in 11 patients with isolated detectable PSA after surgery and local recurrence was established in 4. PSA was detectable later in the follow-up of 45 patients operated on before the PSA assay became available but the date when PSA actually became detectable is not known. A relatively new method of estimating that date and constructing a corresponding Kaplan Meier curve is presented. PSA is an effective marker for monitoring patients after radical prostatectomy as it often detects early persistent disease in patients with detectable measurements 6 months post-operatively or recurrent disease in patients with later rising levels.

Aged↗