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Biomedical subjects

J Wolfe

Publications and source records attributed to J Wolfe.

At least 19 recordsLinked to original sources
PubMed1992

CD2 expression correlates with proliferative capacity of alpha beta + or gamma delta + CD4-CD8- T cells in lpr mice.

The T lymphocytes that accumulate in vast numbers in the lymphoid tissues of lpr/lpr (lpr) mice express a TCR-alpha beta that is polyclonally rearranged, and yet is devoid of surface CD4 or CD8 (CD4-8-) as well as CD2. lpr CD2- alpha beta + CD4-8- T cells exhibit an apparent block in signal transduction, in that when activated they produce little or no IL-2 and proliferate minimally in the absence of exogenous IL-2. In contrast to the predominant hyporesponsive alpha beta + CD4-8- T cells, we observe that a minor subset (1 to 2%) of lpr lymph node CD4-8- cells expresses a TCR-gamma delta and can proliferate upon activation with PMA and ionomycin in the absence of exogenous IL-2. Furthermore, these responsive gamma delta T cells express surface CD2. The functional and phenotypic distinctions of lpr gamma delta T cells led us to identify an analogous minor (4 to 10%) subset of alpha beta + CD4-8- cells in lpr thymus and lymph nodes that does express CD2. Similar to the gamma delta subset, these CD2+ alpha beta + CD4-8- cells are also capable of proliferation and IL-2 production. Thus the capacity for IL-2 production and proliferation by a small proportion of lpr CD4-8- T cells, either alpha beta + or gamma delta +, correlates with their expression of surface CD2. This correlation is supported by the observation that the lpr liver contains actively cycling alpha beta + CD4-8- lymphocytes that are strikingly enriched for CD2 expression. Consequently, unlike the vast proportion of abnormal lpr CD2- CD3+ CD4-8- cells, the CD2+ CD3+ CD4-8- T cells may not express the basic lpr defect, or else are not affected by its presence. These studies suggest that expression of the lpr abnormality may be restricted to a particular T cell lineage. This functional correlation with CD2 expression may be more broadly applicable to phenotypically similar subsets of normal thymocytes, and possibly peripheral tolerized T lymphocytes.

Animals↗
PubMed1992

Motional narrowing of the 2H NMR spectra near the chain melting transition of phospholipid/D2O mixtures.

The reduction in spectral splitting, or motional narrowing, of the deuterium spectra of D2O/phospholipid mixtures near the main chain melting phase transition was studied for palmitoyloleoylphosphatidylcholine (POPC), palmitoyloleoylphosphatidylethanolamine (POPE) and equimolar mixtures of the two at 10% hydration. For POPC the splitting was about 1700 Hz in both the fluid and gel phases, dropping to zero near the phase transition (as reported previously). For POPE the splitting remained approximately constant above the phase transition. Below the phase transition the spectrum showed a single broad line whose linewidth varied between 100 Hz and 800 Hz. This was interpreted as being due to small domains of water within a weakly hydrated crystal. POPC:POPE (1:1) samples exhibited motional narrowing behaviour similar to that for POPC except that the splitting above the phase transition was approximately twice that below the transition. The relatively broad temperature range (approximately 20 K) of the transition is explained using a simple physical model involving lipid fluctuations near the phase transition.

Deuterium↗
PubMed1992

Local tumor recurrence following "radical prostatectomy".

The resurgence of radical retropubic prostatectomy as a commonly employed treatment for organ-confined prostate cancer is largely a result of the reduction in morbidity related to the procedure. One aspect of this reduced morbidity is the potential to preserve potency. The technical points required to perform this procedure must be followed precisely or there is the potential for performing an inadequate cancer operation if these steps are not faithfully followed. We recently encountered a patient with local tumor recurrence because the initial urologist failed to adhere to these principles. A "salvage" procedure was performed.

Adenocarcinoma↗
PubMed1992

Symptom responses of female Vietnam veterans to Operation Desert Storm.

OBJECTIVE: This study examined the status of symptoms of posttraumatic stress disorder (PTSD) in a cohort of women after the onset of Operation Desert Storm. METHOD: Seventy-six non-treatment-seeking Vietnam veterans were obtained from lists of those who recently had participated in other research projects conducted at the National Center for Post-Traumatic Stress Disorder. Before the onset of Operation Desert Storm, subjects had completed a set of psychometrically valid instruments measuring general psychological symptoms and PTSD symptoms (e.g., SCL-90-R, Mississippi Scale for Combat-Related Posttraumatic Stress Disorder). On the basis of the latter scale, subjects were divided into groups with and without PTSD symptoms. At the height of the military conflict, subjects were recontacted and asked to complete the SCL-90-R and the Veterans Update Form, a measure assessing changes in PTSD symptoms. RESULTS: Multivariate analyses indicated that while most female Vietnam veterans experienced some intensification of stress-related symptoms during Operation Desert Storm, those who had previously reported high levels of PTSD were significantly more susceptible to greater distress. CONCLUSIONS: Results of this survey indicate that female Vietnam veterans with prior wartime exposure are an at-risk population for the intensification of stress symptoms after the recurrence of a military conflict.

Adult↗
PubMed1991

Comparison of ZFY and ZFX gene structure and analysis of alternative 3' untranslated regions of ZFY.

We have cloned and sequenced transcripts from the X- and Y-linked zinc-finger genes ZFX and ZFY respectively and discuss a possible mechanism of post-transcriptional control by which these genes can be widely expressed but translated in only specific tissues. We report the identification of a novel 3'UTR (untranslated region) present in ZFY which is highly conserved among primates and contains a series of motifs implicated as mRNA instability determinants. These sequences can be substantially removed by polyadenylation directed from consensus (AATAAA) and non-consensus (AATATAAA) sequences in adult testis. The DNA-binding domains of the ZFY and ZFX proteins are compared using present models for zinc-finger/DNA interactions. Additionally, the genomic organisation of the ZFY coding sequence is presented as compared to that of ZFX.

Amino Acid Sequence↗
PubMed1991

The interaction and fusion of bilayers formed from unsaturated lipids.

The interactions between unsaturated phospholipid bilayers deposited on mica were measured in aqueous solution using a surface forces apparatus. The bilayers were made of L-alpha-dioleoylphosphatidyl-choline (DOPC), L-alpha-dioleoylphosphatidyl ethanolamine (DOPE), and mixtures of the two, and were formed on mica by Langmuir-Blodgett deposition after the lipids were spread on an aqueous substrate from a chloroform solution. The forces are interpreted as electrostatic double-layer and van der Waals forces with long range, and a strong repulsion (hydration or steric force) at distances of several nm. Together they produce a region of weak attraction (a secondary minimum) at 5 nm (DOPE) and 6 nm (DOPE). Fusion of two bilayers into one was observed when the local force per unit area was 2-3 MPa. Other researchers report that phosphatidylethanolamine in vesicles enhances fusion. In this study using deposited bilayers, the presence of DOPE in a DOPC bilayer did not promote fusion, nor did DOPE bilayers fuse more easily than DOPC. The value of the force per unit area at which the two bilayers fuse into one was however decreased by several orders of magnitude when the bilayers were formed from lipids kept in chloroform solution for several days or more. Chromatography showed traces of lipid degradation products in such chloroform solutions.

Chemical Phenomena↗
PubMed1991

The use of irradiation and fusion gene transfer (IFGT) hybrids to isolate DNA clones from human chromosome region 9q33-q34.

We have generated somatic cell hybrids containing fragments of human chromosome arm 9q by an irradiation and fusion technique. No selection for human material was imposed, but of 23 clones analyzed most contained human DNA sequences and many contained multiple fragments of the human chromosome arm. A hybrid that appears to contain only two small fragments of human DNA from the regions of q33 and q34 has been used as a source from which to clone probes specific to those areas of the chromosome.

Animals↗
PubMed1991

Sex determination and species exclusion in forensic samples with probe cY97.

A total of 120 human samples of blood, saliva and semen stains, hair roots, bone and skin fragments, obtained from 30 males and 16 females were analyzed in Southern blots with probe cY97. Only the male samples gave a specific band of 5.7 kb. In dot blot, under high stringency conditions, male DNA gave signals equivalent to a quantity of female DNA eight times higher. Probe cY97 did not react with 9 different vertebrate species but gave a signal for monkey DNA when used at low stringency. The advantage of using a probe specific for the centromeric region for sex determination and species exclusion is discussed.

Animals↗
PubMed1991

D12S56: a highly polymorphic locus on human chromosome 12q14.

A CA repeat, subcloned from a cosmid, has been assigned to chromosome 12 by use of a panel of somatic cell hybrids. The assignment was confirmed by fluorescent in situ hybridization and the site further localized to 12q14. The repeat is highly polymorphic and should be useful for genetic mapping.

Base Sequence↗
PubMed1990

A physical map of the human PI and AACT genes.

We have used probes from the human genes PI, PIL, and AACT (alpha 1-antitrypsin, alpha 1-antitrypsin-related sequence, and alpha 1-antichymotrypsin) to make a pulsed-field map of the surrounding region of 14q31-32. We have discovered that the PI-PIL gene cluster is only 220 kb away from the AACT gene and that it is orientated in the opposite direction. The comparatively short distance between the genes comes as a surprise given previous estimates of the level of genetic recombination between them.

Bacterial Proteins↗
PubMed1990

The human Y chromosome shows a low level of DNA polymorphism.

Six new Y-specific probes have been isolated and are reported. Along with another six already described they have been used in a systemic search for male specific RFLPs. An overall number of 46515 nucleotides have been screened with 12 enzymes and no polymorphic pattern observed. Our data reveal a greatly reduced level of polymorphism compared with other chromosomes.

Animals↗
PubMed1990

Antituberculous drug resistance in central Haiti.

To determine the prevalence of antituberculous drug resistance in Haiti, we conducted a 1-yr survey in a central district. From a bacillary positive (smear and/or culture positive) case rate of 80/100,000, there were 282 patients from whom Mycobacterium tuberculosis was cultured. Each isolate was packaged and delivered to Canada where speciation and drug susceptibility testing were performed. Reported resistances are those using the proportions method (Laboratory Center for Disease Control, Ottawa, Canada). Resistance to one or more drugs was found in 22% of isolates. Age was the most important predictor of resistance in Haiti; resistance rates for age groups less than 14, 14 to 29, 30 to 44, greater than or equal to 45 were 8, 19, 22, and 31%, respectively. In patients not known to have received antituberculous drugs in the past, resistances were isoniazid (19%), streptomycin (5%), ethambutol (2%), ethionamide (2%), rifampin (1%). We conclude that antituberculous drug resistance is prevalent in Haiti, especially in older age groups, and that in persons with no known antituberculous drug use in the past, resistance to isoniazid is significant.

Adolescent↗
PubMed1979

Properties of bilayer membranes in the phase transition or phase separation region.

The increase in passive permeability of bilayer membranes near the phase transition temperature is usually explained as caused by either the increase in the amount of 'boundary lipid' present in the membrane, or by the increase in lateral compressibility of the membrane. Since both the amount of 'boundary lipid' and the lateral compressibility show a similar anomaly near the transition temperature, it is difficult to distinguish experimentally between the two proposed mechanisms. We have examined some details of both of the proposed pictures. The fluid-solid boundary energy, neglected in previous work, has been computed as a function of the domain size. For a single component uncharged lipid bilayer, the results rule out the existence of even loosely defined solid domains in a fluid phase, or vice versa. Thermodynamic fluctuations, which are responsible for anomalous behaviour near the phase transition temperature, are not intense enough to approximate the formation of a domain of the opposite phase. Turning next to lateral compressibility of bilayer membranes we have considered two-component mixtures in the phase separation region. We present the first calculation of lateral compressibility for such systems. The behaviour shows interesting anomalies, which should correlate with existing and future data on transport across membranes.

Lipid Bilayers↗