Posttraumatic stress disorder and war-zone exposure as correlates of perceived health in female Vietnam War veterans

Previous studies have identified traumatic exposure and posttraumatic stress disorder (PTSD) as predictors of physical health complaints without considering the relationship between exposure and PTSD. This study examined the unique associations of war-zone exposure and PTSD with perceived physical health outcomes in a nontreatment-seeking sample of 109 female veterans of the Vietnam War who responded to a series of psychological, exposure, and health questionnaires. Both PTSD and exposure were associated with reports of negative health outcomes when each variable was not adjusted for the other. The effects associated with exposure decreased when PTSD was controlled for, whereas the effects associated with PTSD remained when exposure was controlled for. Results suggest that effects of traumatic exposure on perceived health are partially mediated by increases in PTSD after exposure, supporting studies on the effects of stress on health.

Do trehalose and dimethyl sulfoxide affect intermembrane forces?

The sugar trehalose is produced in some organisms that survive dehydration and desiccation, and it preserves the integrity of membranes in model systems exposed to dehydration and freezing. Dimethyl sulfoxide, a solute which permeates membranes, is added to cell suspensions in many protocols for cryopreservation. Using a surface forces apparatus, we measured the very large, short-range repulsion between phosphatidylcholine bilayers in water and in solutions of trehalose, sorbitol, and dimethyl-sulfoxide. To the resolution of the technique, the force-distance curves between bilayers are unchanged by the addition of trehalose or sorbitol in concentrations exceeding 1 kmol.m-3. A relatively small increase in adhesion in the presence of trehalose and sorbitol solutions may be explained by their osmotic effects. The partitioning of trehalose between aqueous solutions and lamellar phases of dioleylphosphatidylcholine was measured gravimetrically. The amount of trehalose that preferentially adsorbs near membrane surfaces is at most small. The presence of dimethyl sulfoxide in water (1:2 by volume) makes very little difference to the short-range interaction between deposited bilayers, but it sometimes perturbs them in ways that vary among experiments: free bilayers and/or fusion of the deposited bilayers were each observed in about one-third of the experiments.

Inhibition of human vascular smooth muscle cell proliferation by lovastatin: the role of isoprenoid intermediates of cholesterol synthesis

Restenosis remains the largest single obstacle to the long-term success of invasive vascular interventions. Lovastatin, an HMG-CoA reductase inhibitor, has been shown to reduce myointimal hyperplasia in animal models of restenosis and in one clinical coronary restenosis trial. We have assessed the effect of lovastatin on the growth of cultured human vascular smooth muscle cells derived from saphenous vein and vascular graft stenoses. Lovastatin (2 microM) inhibited proliferation over 14 days in saphenous vein (and graft stenoses) derived vascular smooth muscle cells by 42% and 32% respectively: this was not significantly different. Lovastatin (10 microM) reduced [methyl 3H]-thymidine uptake by 51% in saphenous vein-derived cells. These concentrations were significantly higher than those achieved in plasma during therapeutic dosage. Lovastatin-induced inhibition of vascular smooth muscle cell proliferation and [methyl 3H]-thymidine uptake was completely reversed by adding mevalonate (100 microM) but cholesterol (10-40 micrograms ml-1) had no effect. Isopentenyl adenine (25-50 microM) did not affect the inhibition of [methyl 3H]-thymidine uptake by lovastatin (10 microM), but farnesol (20 microM), another isoprenoid precursor of cholesterol synthesis, reversed the antiproliferative effect.

Consistent responses of the human vascular smooth muscle cell in culture: implications for restenosis

PURPOSE

The mechanisms whereby restenoses occur at discrete sites within the vasculature remain uncertain. We have recently reported that vascular smooth muscle cells (VSMC) derived from patients with graft stenoses are resistant to growth inhibition by heparin. In this study, we have examined whether VSMC proliferation rates and responses to inhibition by heparin vary according to the individual or the anatomic site of origin.

METHODS

Long saphenous veins from seven patients were divided into proximal, middle, and distal portions, and VSMC were cultured separately from each. VSMC proliferation in response to 15% fetal calf serum +/- 100 micrograms/ml heparin was measured by counting triplicate samples at 0, 3, 7, 10, and 14 days. This experiment was repeated from the second to the sixth passage (n = 6) and for artery and vein pairs derived from four additional patients.

RESULTS

Differences between vein segment cultures of individual veins were found not to differ significantly from experimental error for either proliferation or heparin inhibition and were not altered by repeated passage (ANOVA). There were, however, significant differences in sensitivity to heparin inhibition between patients (p = 0.02) (ANOVA). There were no significant differences between paired samples of artery and vein for either proliferation or heparin inhibition (Mann-Whitney test).

CONCLUSIONS

VSMC growth characteristics reflect the individual patient and are maintained in cell culture.

PUVA bath therapy strongly suppresses immunological and epidermal activation in psoriasis: a possible cellular basis for remittive therapy

Psoriasis is characterized by alterations in both the epidermis and dermis of the skin. Epidermal keratinocytes display marked proliferative activation and differentiate along an "alternate" or "regenerative" pathway, while the dermis becomes infiltrated with leukocytes, particularly interleukin 2 (IL-2) receptor-bearing "activated" T cells. Psoralens, administered by the oral route, have therapeutic effects in psoriasis when photochemically activated by ultraviolet A light (PUVA therapy). Recently psoralen bath therapy has been introduced to more effectively deliver this agent to the diseased skin. We have correlated the efficacy of PUVA bath therapy with its effects on specific molecular and cellular parameters of disease, in 10 consecutive patients with recalcitrant psoriasis. Rapid clearing of lesions occurred in 8 out of 10 patients. Biopsies were taken from lesional and nonlesional skin before and after a single round of therapy, and observation was continued in our Clinical Research Center at The Rockefeller University. Enumeration of cycling keratinocytes with the Ki-67 monoclonal antibody showed that PUVA reduced cell proliferation by 73%. The pathological increase in insulin-like growth factor 1 (IGF-1) receptors was reversed, whereas epidermal growth factor (EGF) receptors, which are also increased in psoriasis, remained unchanged. Keratinocyte proteins that are expressed in abnormal sites of the epidermis during psoriasis, i.e., keratin 16, filaggrin, and involucrin, were, after PUVA treatment, localized to their normal sites. Epidermal and dermal T-lymphocytes (CD3+), as well as CD4+, CD8+, and IL-2 receptor+ subsets, were strongly suppressed by PUVA, with virtual elimination of IL-2 receptor+ T cells in some patients. Consistent with diminished lymphocyte activation, HLA-DR expression by epidermal keratinocytes was markedly reduced in treated skin. In comparison to cyclosporine treatment of psoriasis, PUVA therapy leads to more complete reversal of pathological epidermal and lymphocytic activation, changes which we propose to be the cellular basis for a more sustained remission of disease after PUVA treatment.

Growth inhibition of human vascular smooth muscle cells by fenofibrate: a possible therapy for restenosis

OBJECTIVE

The aim was to assess the growth inhibitory effect of fibrates on human vascular smooth muscle cells. Restenosis is the most important factor limiting the long term success of invasive vascular interventions and there is as yet no effective preventive treatment. Platelet derived growth factor (PDGF) is considered to be an important growth promoting agent for vascular smooth muscle cells (VSMC) and fenofibric acid (a hypolipidaemic drug) has been reported to be a PDGF antagonist.

METHODS

The effect of the fibrate drugs fenofibrate, clofibrate, bezafibrate, and gemfibrozil were examined on the proliferation of cultured human vascular smooth muscle cells derived from saphenous vein (n = 20) and graft stenoses (n = 7).

RESULTS

Fenofibrate (100 microM) produced potent inhibition (48%) of VSMC proliferation at a concentration equivalent to that of its circulating metabolite fenofibric acid, but none of the other drugs produced any significant effect on growth. VSMC derived from graft stenoses were equally sensitive to inhibition as saphenous vein derived controls, in contrast to our previous work which reported that graft stenosis derived VSMC were resistant to growth inhibition by the physiological inhibitor heparin. The antiproliferative effect of fenofibrate was independent of inhibition of cellular cholesterol synthesis or toxicity. Fenofibrate inhibited VSMC growth induced by 15% fetal calf serum, PDGF, and basic fibroblast growth factor to a similar degree, indicating that it is not a specific PDGF antagonist.

CONCLUSIONS

Fenofibrate is not a specific PDGF antagonist. Fenofibric acid, one of the principal metabolites of fenofibrate, did not produce any inhibition of growth, suggesting that oral administration of fenofibrate would not be efficacious. Fenofibrate is the first potent inhibitor to be described for VSMC derived from human myo-intimal hyperplastic lesions.

Effect of calcium channel blockers on the growth of human vascular smooth muscle cells derived from saphenous vein and vascular graft stenoses

Vascular restenosis after invasive interventions is an important clinical problem for which no preventive pharmacologic therapy exists. Calcium channel blockers have been shown to inhibit myointimal hyperplasia in animal models of restenosis and in some small and flawed clinical coronary restenosis trials. We examined the inhibitory effect of amlodipine, verapamil, and diltiazem on the growth of cultured human vascular smooth muscle cells (VSMC) derived from saphenous vein (n = 20) and graft stenoses (n = 7), in 14-day proliferation assays and [methyl 3H]thymidine uptake studies. Amlodipine and verapamil produced significant inhibition (30%) of VSMC proliferation and DNA synthesis at 10 microM but not at 500 nM-1 microM. To our knowledge, this is the first study to examine the antiproliferative effect of calcium channel blockers in VSMC derived from human graft stenoses. Growth inhibition of VSMC from graft stenoses was not significantly different from that of control saphenous vein-derived cells. We conclude, therefore, that calcium channel blockers inhibit human VSMC proliferation in vitro, regardless of whether the cells were grown from graft stenoses or saphenous vein. However, the concentrations at which these calcium channel blockers elicit antiproliferative effects may not be attainable during therapeutic dosing in humans.

Substance abuse and post-traumatic stress disorder comorbidity

This article reviews the extant literature on substance abusers with and without a comorbid diagnosis of post-traumatic stress disorder (PTSD) and reveals the discontinuity between clinical lore and empirical research. Included is an overview of PTSD-substance abuse theoretical models and comorbidity prevalence rates, as well as an evaluation of the comparative data on treatment outcome and psychosocial factors, such as coping skills, for PTSD versus non-PTSD substance abusers. In addition, we discuss the controversy surrounding sequential versus simultaneous treatment approaches for such 'dually-diagnosed' patients. We conclude by identifying gaps in current knowledge about the nature and impact of PTSD on substance abuse treatment outcome and outlining needs for future research.

Reversal of hyporesponsiveness in lpr CD4-CD8- T cells is achieved by induction of cell cycling and normalization of CD2 and p59fyn expression

T cells freshly isolated from the peripheral lymph nodes of autoimmune MRL lpr/lpr (lpr) mice contain a large proportion of functionally non-mature T cell receptor (TcR)-alpha beta+CD3+CD2-CD4-CD8- T cells displaying the B cell isoform of CD45, B220. These cells are hyporesponsive as defined by minimal interleukin-2 (IL-2) production and proliferation in response to stimulation. However, increased levels of inositol phosphates and a rapid mobilization of Ca2+ do occur upon stimulation of the TcR/CD3 complex. Furthermore, lpr CD4-CD8-T cells contain high levels of transcripts for the src-family tyrosine kinase p59fyn, and express a constitutively tyrosine-phosphorylated CD3-zeta chain. These features bear a certain resemblance to anergized T cells. These similarities are extended to show that culturing of lpr CD4-CD8- T cells in the presence of IL-2 in combination with phorbol 12-myristate 13-acetate and ionomycin initiates cell cycling and results in the gain of function; re-stimulation now yields IL-2-dependent proliferation in the absence of exogenous IL-2. In parallel with this gain in function, the population of cells obtained after 1 week in culture retains the TcR-alpha beta + CD4-CD8- phenotype, yet displays increased levels of CD2, decreased surface B220, and normal amounts of p59fyn-specific transcripts. These findings show that cell cycling is associated with the recovery of functional capabilities by lprCD4-CD8-T cells and is closely allied with surface CD2 expression. Thus, the hyporesponsiveness of lpr T cells is not a fixed state.

Hydration forces and membrane stresses: cryobiological implications and a new technique for measurement

Very large, repulsive forces are measured between various surfaces in water at separations of about a nanometer or less. These forces are important in cryobiology because extracellular freezing usually causes extreme osmotic dehydration of cells. This brings membranes and macromolecules into close approach, and imposes large, anisotropic stresses on them. It is therefore important to study these forces at freezing temperatures. We have studied the freezing and thawing behaviour of lamellar phases of egg yolk lecithin and D2O. Force-hydration and force-separation relations are obtained from the deuterium nuclear magnetic resonance signal as a function of temperature. From these measurements we estimate the magnitude of freezing-induced membrane stresses and discuss their effect on the response of cells and organelles to freezing and thawing.

Localization of the retinoid X receptor alpha gene (RXRA) to chromosome 9q34

The retinoid X receptor alpha is one of a number of retinoic acid receptors which are members of the steroid/thyroid hormone superfamily. Localization of RXRA was achieved using the polymerase chain reaction on a panel of somatic cell hybrids. A cosmid clone was isolated using the RXRA PCR product, and this was used to further localize the gene by fluorescence in situ hybridization to chromosome 9q34 distal to the dopamine beta hydroxylase gene (DBH). This mapping position was confirmed by PCR on a panel of translocation hybrids.

Mapping of RXRB to human chromosome 6p21.3

Retinoid X Receptor beta (RXRB) is a member of the retinoid X receptor (RXR) family of nuclear receptors which are involved in mediating the effects of retinoic acid (RA). We have confirmed the localization of RXRB to chromosome 6 and we have mapped the gene to chromosome 6p21.3-p21.1 by PCR amplification of 5' untranslated sequence in panels of rodent-human somatic cell hybrids and to 6p21.3 by fluorescent in situ hybridization.

CD2 expression on murine intestinal intraepithelial lymphocytes is bimodal and defines proliferative capacity

The CD2 molecule is normally expressed on nearly all murine lymphocytes, and is co-stimulatory in T cell activation via the antigen receptor (TCR). A naturally occurring T lymphocyte population that is bimodal for CD2 expression was found in the intestinal intraepithelial lymphocytes (IEL). TCR alpha beta + IEL contain CD2- and CD2+ cells of approximately equal proportion, while TCR gamma delta + IEL are predominantly CD2-. The proliferative response of IEL to stimulation with an anti-CD3 mAb or with PMA plus ionomycin co-segregated with CD2 expression; the CD2+ subset proliferated vigorously under these conditions while the CD2- subset was much less responsive. The responding CD2+ IEL contained both TCR alpha beta + and TCR gamma delta + cells. However, activation of the CD2- IEL with anti-CD3 mAb resulted in only the expansion of TCR gamma delta + IEL, while activation with PMA plus ionomycin did not promote expansion of either the TCR alpha beta + or the TCR gamma delta + IEL. These findings parallel observations in the autoimmune lpr mouse, where massive numbers of peripheral TCR alpha beta + CD4-CD8- T cells that lack CD2 expression are also hyporesponsive to mitogenic stimulation. The apparent anergy of CD2- TCR alpha beta + IEL, as well as CD2- T cells from lpr mice, demonstrates that the absence of CD2 on TCR alpha beta + T lymphocytes co-segregates with nonresponsiveness.

Antituberculous drug resistance in Manitoba from 1980 to 1989

OBJECTIVES

To estimate the magnitude of antituberculous drug resistance and identify the risk factors for its development in tuberculosis patients in Manitoba over a 10-year period. As well, to examine the clinical course of the patients whose initial or subsequent isolates of Mycobacterium tuberculosis were resistant to one or more drugs.

DESIGN

Comparison of drug-resistant and non-drug-resistant cases of tuberculosis.

SETTING

Manitoba.

PATIENTS

All people with tuberculosis reported to the Central Tuberculosis Registry of Manitoba between Jan. 1, 1980, and Dec. 31, 1989.

MAIN OUTCOME MEASURES

Of 1478 cases of active tuberculosis 1086 were culture positive, and drug susceptibility testing was performed in these cases. The clinical course, including outcome of treatment, of all drug-resistant cases was described.

RESULTS

Of 1086 culture-positive cases of tuberculosis 77 (7.1%) were drug resistant. Odds ratios suggested that the risk of drug resistance was significantly higher among the immigrants than among the other Canadians. Compared with the other Canadians the risk of drug resistance was 9.9 times greater among the immigrants in whom tuberculosis developed within the first year after arrival in Canada and 5.4 times greater among the immigrants in whom it developed 2 to 5 years after arrival in Canada. Of the 71 patients with drug-resistant disease whose type of resistance was known 62% had never taken antituberculous drugs before and 38% had. Most (91%) of the 77 cases of drug-resistant disease were resistant to first-line drugs, especially isoniazid and streptomycin. Thirty-two (42%) of the 77 cases were resistant to two or more first-line drugs. Of patients with drug-resistant disease a subgroup of 10 had disease that became resistant to several drugs over the 10-year period. The outcome of treatment in these individuals was poor, and they presented a particular public health problem.

CONCLUSION

Resistance to one or more first-line antituberculous drugs continues to complicate the treatment of tuberculosis and may facilitate the spread of the disease.

Early encounters of the repetitive kind: a prelude to cell adhesion in conjugating Tetrahymena thermophila

The relationship between direct cell contacts and subsequent cell-cell adhesion was studied in the ciliated protozoan, Tetrahymena thermophila. During sexual reproduction, adhesion into pairs begins at approximately 1 hr after mixing starved complementary mating types. However, direct contacts between cells prior to pairing are known to be required for the development of adhesion-readiness. We find here that the initial contact interactions are necessary but not sufficient to drive the cells to adhesion-readiness. Secondary interactions are needed. Two distinct experimental strategies were used. First, we examined the effects of a mutant that is unable to pair but which can stimulate two different wild-type mating type cells to pair when mixed. We showed that stimulation by the mutant is only partial; in response to mutant cells, wild-type cells ceased forming food vacuoles but did not undergo tip transformation or concanavalin A (Con A)-receptor tipping. Further, kinetic analysis shows that when mixed together, pair-formation among partially stimulated wild-type cells is slightly delayed, allowing time for these pre-pairing processes to occur. This indicates that, beyond the initial contact interaction, mutant-stimulated wild-type cells require a subsequent interaction which cannot be fulfilled by the mutants. Secondly, we found that by blocking contact interactions between wild-type mating types at various time intervals after they were mixed, additional increase in tip transformation and Con A receptor tipping was prevented. Further, both processes underwent a regression. This indicates that multiple contact interactions are required to drive the cells to adhesion readiness and to prevent developmental slip-back.

Cellular biology of human intimal hyperplastic stenosis

Restenosis after angioplasty and vascular surgery remains a major unsolved clinical problem. Vascular smooth muscle cell (VSMC) hyperplasia is an invariable response, but in 20-50% of cases proceeds to compromise the vessel lumen. We sought to identify cellular characteristics of human VSMC which are associated with restenosis. Human VSMC were grown from 135 samples of vascular tissue derived from patients undergoing primary cardiovascular surgery and revision surgery for restenosis. Cells derived from normal vein and artery, atherosclerotic plaques and from stenotic lesions were studied for successful proliferation in cell culture. Furthermore, growth rates were measured in response to 15% foetal calf serum +/- inhibition with heparin (100 micrograms/ml). Significantly fewer cells from atherosclerotic plaques progress to the third passage in cell culture than those derived from stenoses and controls (p < 0.001, Chi square) and growth rates after the third passage could not be studied in these cells. Of cells that progress to this stage, growth rates do not differ between stenosis-derived and normal cells under standard conditions. VSMC from mature atherosclerotic plaques may have undergone senescent changes. Stenosis-derived cells do not grow more rapidly than normal cells, but are significantly less sensitive to heparin (p < 0.001, Mann-Witney test), which is a major physiological inhibitor of VSMC growth. Differences in biological characteristics of human VSMC, observed in cell culture, may provide important insights into human vascular disease.

Abnormal growth regulation of vascular smooth muscle cells by heparin in patients with restenosis

Proliferation of vascular smooth muscle cells (VSMC) underlies myointimal hyperplasia, which can lead to restenosis after angioplasty and vascular surgery. We propose that some individuals have an intrinsic capacity for this exaggerated response to vascular injury, partly through decreased sensitivity to the physiological growth inhibitor heparin. We investigated the effect of heparin on VSMC from restenotic lesions and from apparently normal vessels of the same patients, and VSMC from control patients undergoing primary bypass procedures. Cells from patients with restenosis (both restenotic lesion and undiseased vein) showed much lower sensitivity to growth inhibition by heparin than the controls (median inhibition 8 [95% Cl -2 to 25] vs 22 [15-44]%, p < 0.001); this finding suggests aberrant growth regulation in these cells.

Loss of contrast sensitivity in diabetic patients with LOCS II classified cataracts

Contrast sensitivity function (CSF) was assessed in a population of diabetics with moderate cataracts to determine if CSF testing provides more information about visual dysfunction than Snellen or Lotmar interferometric visual acuity. With the Lens Opacities Classification Systems Version II (LOCS II) of cataract classification it was possible to grade accurately the type and severity of cataract and nuclear brunescence. The presence of statistically significant relationships between increasing LOCS II classification (worsening cataract) and diminished function, even when the regression model was controlled for Snellen visual acuity, supports the thesis that CSF measurements do provide more information about cataract related visual loss than Snellen acuity alone. Statistically significant (p < or = 0.05) relationships existed between different morphological types of cataract, nuclear colour, and CSF at specific frequencies. The frequencies affected differed with cataract type or nuclear colour, and with distance and near CSF.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Differences in abstraction ability with age

Three tests of abstraction were administered to 89 optimally healthy subjects aged 30-79. Performance on all 3 tasks showed significant differences with age. This was primarily, although not entirely, the result of deficits in performance by the 70-year-old subjects. These results do not appear to be related to changes in memory ability or to a differential increase in a particular type of abstraction error.

Differences in abstraction ability with age

Three tests of abstraction were administered to 89 optimally healthy subjects aged 30-79. Performance on all 3 tasks showed significant differences with age. This was primarily, although not entirely, the result of deficits in performance by the 70-year-old subjects. These results do not appear to be related to changes in memory ability or to a differential increase in a particular type of abstraction error.

Irreducible dislocation of the great toe following a sports injury. A case report

The increasing number of competitive and recreational athletes has resulted in more sports-related foot injuries. An understanding of the sesamoid anatomy of the foot will facilitate management of these injuries. We recommend use of the dorsal approach in the surgical treatment of irreducible interphalangeal dislocations.

The effects of prenatal alcohol exposure on radial arm maze performance in adult rats

The hippocampal formation is sensitive to the in utero exposure to ethanol. It is one brain area thought to play an important role in spatial memory. We examined radial arm maze performance in rats exposed to ethanol prenatally. Pregnant rats were placed into the following treatment groups: LC, 17% EDC (ethanol-derived calories), 35% EDC, PF 35% or PF 17%. The LC group was fed lab chow and water ad lib, the 17% EDC and 35% EDC groups were fed a liquid diet containing either 3.3% or 6.7% v/v ethanol, respectively. Pair-fed controls were fed the same volume of an isocaloric diet as was consumed by their respective ethanol-treated groups. At birth, litters were culled to six and cross fostered to untreated surrogate mothers. Testing was initiated at 60 days of age and continued until the test criterion was satisfied. One-half of the rats in the 35% EDC group did not reach criterion. The remainder of the 35% EDC group and the 17% EDC rats attained criterion but required twice as many trials as their respective pair-fed controls. These results suggest that in utero administration of ethanol affects spatial memory capacity in rat, an observation consistent with other deficits seen in hippocampus of rats prenatally exposed to ethanol.

Effects of prenatal alcohol on gamma-glutamyl transpeptidase in various brain regions

Prenatal exposure of rats to alcohol produces morphological, biochemical, behavioral and physiological abnormalities. The enzyme gamma-glutamyl transpeptidase activity is increased when an animal is exposed to alcohol chronically. We examined the effect of the in utero exposure to alcohol on the regional brain distribution of gamma-GTP. Pregnant rats were placed into the following treatment groups: LC (ad lib lab chow and water), PF (pair-fed), 10% EDC (ethanol derived calories), 20% EDC and 35% EDC. The LC group was fed lab chow and water ad lib, the PF, 10% EDC, 20% EDC and 35% EDC groups were fed a liquid diet containing either 0%, 2%, 4% or 6.7% v/v ethanol, respectively. All the treatment groups received the same volume of an isocaloric diet as was consumed by the 35% EDC group. At birth, litters were culled to six and cross fostered to untreated surrogate mothers. Pups were sacrificed at 30 days of age and brains dissected into 8 regions. Each brain region was homogenized and divided into soluble and membrane bound fractions by centrifugation and digestion with deoxycholic acid. gamma-GTP activity was then measured. It was determined that the in utero exposure to alcohol produces an increase in brain gamma-GTP activity. The increase in gamma-GTP activity in some areas of brain is maintained at least until the animals are 30 days old. Alcohol treatment had no effect on the activity associated with the soluble form of enzyme. However, the activity associated with the membrane bound form of the enzyme was increased in several brain regions.(ABSTRACT TRUNCATED AT 250 WORDS)

Concanavalin A inhibits mating type recognition in Tetrahymena

The lectin concanavalin A (Con A) inhibits adhesion of cells of complementary mating types into pairs during conjugation in the ciliate Tetrahymena thermophila. Distinct changes in protein synthesis occur in conjugating Tetrahymena, starting before cells have paired, as a result of a preliminary interaction, costimulation, involving nonadhesive, contact-mediated, specific cell-cell recognition. We report here that ConA inhibits costimulation-induced protein synthesis changes. We interpret this result as evidence that Con A inhibits cellular recognition, independent of cell-cell adhesion, in Tetrahymena.

Can hydration forces induce lateral phase separations in lamellar phases?

Large repulsive forces measured between membranes of lamellar lipid phases at low hydration are attributed to hydration interactions which vary widely among lipid species. We include this interaction in a model of lamellar phases of two membrane components (two lipids or lipid and protein). The surface polarization of a mixture is taken as a linear combination of those of the components. The model predicts phase separation at low hydration. This may have important consequences for living cells which are dehydrated either by the osmotic effects of tissue freezing, or by desiccation in unsaturated atmospheres.

Recognition and transport of adenine derivatives with synthetic receptors

Several new synthetic agents show high affinity for binding adenine derivatives. The structures feature complementary hydrogen bonds that cause the molecular chelation of the purine nucleus. The high lipophilicity of the new agents permits the transport of adenosine and deoxyadenosine across organic liquid membranes. The use of synthetic receptors for small biological targets may have application in drug delivery.