Affinity labeling of rat glutathione S-transferase isozyme 1-1 by 17beta -iodoacetoxy-estradiol-3-sulfate.

Rat liver glutathione S-transferase, isozyme 1-1, catalyzes the glutathione-dependent isomerization of Delta(5)-androstene-3,17-dione and also binds steroid sulfates at a nonsubstrate inhibitory steroid site. 17beta-Iodoacetoxy-estradiol-3-sulfate, a reactive steroid analogue, produces a time-dependent inactivation of this glutathione S-transferase to a limit of 60% residual activity. The rate constant for inactivation (k(obs)) exhibits a nonlinear dependence on reagent concentration with K(I) = 71 microm and k(max) = 0.0133 min(-1). Complete protection against inactivation is provided by 17beta-estradiol-3,17-disulfate, whereas Delta5-androstene-3,17-dione and S-methylglutathione have little effect on k(obs). These results indicate that 17beta-iodoacetoxy-estradiol-3-sulfate reacts as an affinity label of the nonsubstrate steroid site rather than of the substrate sites occupied by Delta5-androstene-3,17-dione or glutathione. Loss of activity occurs concomitant with incorporation of about 1 mol 14C-labeled reagent/mol enzyme dimer when the enzyme is maximally inactivated. Isolation of the labeled peptide from the chymotryptic digest shows that Cys(17) is the only enzymic amino acid modified. Covalent modification of Cys(17) by 17beta-iodoacetoxy-estradiol-3-sulfate on subunit A prevents reaction of the steroid analogue with subunit B. These results and examination of the crystal structure of the enzyme suggest that the interaction between the two subunits of glutathione S-transferase 1-1, and the electrostatic attraction between the 3-sulfate of the reagent and Arg(14) of subunit B, are important in binding steroid sulfates at the nonsubstrate steroid binding site and in determining the specificity of this affinity label.

Interactions between HIV-infected monocytes and the extracellular matrix: increased capacity of HIV-infected monocytes to adhere to and spread on extracellular matrix associated with changes in extent of virus replication and cytopathic effects in infected cells.

Monocytes express cell surface receptors for extracellular matrix (ECM) proteins of basement membranes. These receptors are engaged during extravasation of cells through capillary endothelium into tissue. The number of human immunodeficiency virus (HIV)-infected monocytes that adhered to ECM over 2 h was threefold higher than that of uninfected control cells. This difference was ECM specific and was not observed with a bovine serum albumin substrate. Enhanced adhesion to ECM was evident in monocytes by 4 days after HIV infection and increased through 10 days. Monocytes exposed to a T cell-tropic HIV strain that binds to but does not replicate in monocytes showed no changes in adherence to ECM. Thus, productive infection of monocytes by HIV induces a significant increase in the capacity of these cells to interact with ECM. Enhanced adhesion of HIV-infected monocytes to ECM was associated with increased spreading: at 12 h, sixfold more HIV-infected monocytes were spread on ECM than were uninfected control cells. Cell processes of HIV-infected monocytes formed a complex network on ECM: many of these cells expressed HIV proteins as detected by indirect immunofluorescence. HIV-associated cytopathic effects and levels of virion-associated reverse transcriptase activity depended on the substrate to which monocytes were attached. Virus replication and cytopathic effects in monocytes adhered to ECM, fibronectin, or plastic alone were comparable. In contrast, HIV-infected monocytes attached to laminin showed a significant increase in virus replication and in extent of cytopathic effects through 2 weeks after infection. The lowest levels of HIV replication and cytopathic effects were in monocytes attached to collagen IV. Interactions between monocytes and ECM profoundly affect the manner in which these cells control HIV infection: HIV infection changes the capacity of infected monocytes to attach and spread on ECM; attachment to ECM alters the extent of virus replication in infected cells.

The relationship between elbow position and grip strength.

Forty-six graduate students participated in a study to investigate the effect of elbow position on grip-strength measurements. Sixteen males and 30 females, aged 21 to 46 years, participated in the study. Data collection procedures followed standardized grip-strength testing guidelines established by the American Society of Hand Therapists, with the exception of elbow position. Grip-strength measurements were taken with the elbow positioned at 0 degree, 45 degrees, 90 degrees, and 135 degrees of flexion. The results showed a significantly stronger grip-strength measurement at 0 degree of flexion and the weakest grip-strength measurement at 135 degrees of flexion. This study supports the use of a standardized method for hand-strength testing. The knowledge that grip-strength measurement is highest when the elbow is fully extended could affect treatment planning.

Contralateral v ipsilateral cane use. Effects on muscles crossing the knee joint.

Although using a cane contralaterally has been shown to reduce muscular activity across the hip joint, little is known about effects on the knee. We measured muscular activity around the knee in 10 able-bodied subjects. We simultaneously recorded integrated rectified surface electromyographic activity from the right quadriceps, medial and lateral hamstrings, gastrocnemius and hip abductors during various standing maneuvers: two-legged stance, unsupported one-legged stance and one-legged stance putting maximal, moderate (20% body weight) or minimal (10% body weight) force through an ipsilateral or contralateral cane. Electromyographic activity was expressed as the percentage of that recorded during unsupported one-legged stance in each muscle. Hip abductor activity was lowest when maximal weight was placed through a contralateral cane (66%) and highest with maximal weight ipsilaterally (424%). Medial hamstrings activity increased by 404% and 200%, respectively, when maximal and moderate force was applied to a contralateral cane, although there was no change with ipsilateral cane. Lateral hamstrings were also most active during contralateral cane use. Quadriceps activity decreased using a cane in either hand with moderate or minimal force (range 57 to 84%). Gastrocnemius activity decreased during contralateral (60 to 66%) and ipsilateral (75 to 96%) cane use. This data suggests that forces generated by muscular activity around the knee are not uniformly diminished by holding a cane in the contralateral hand and may even be increased.

Enhanced HIV-1 replication in retinoid-treated monocytes. Retinoid effects mediated through mechanisms related to cell differentiation and to a direct transcriptional action on viral gene expression.

Vitamin A and other retinoids have profound effects on macrophage differentiation and function. Such effects could alter interactions between HIV and tissue macrophages, a principal target cell and reservoir for virus during HIV disease. Indeed, retinoids are used to treat various symptoms associated with HIV infection. We show that levels of virus replication in monocytes cultured 7 days before and continuously after HIV infection in 1 to 10 microM retinoic acid were 10- to 20-fold greater than those of control cells. No direct toxicity (detachment from substrate or cell death) was evident in infected or control monocytes treated with less than or equal to 10 microM retinoic acid. Maximum effects of retinoic acid (50% maximum effect was at 0.8 +/- 0.1 microM) required 5 to 7 days treatment before infection and persisted without additional treatment through more than 4 wk. RT activity in cultures of retinoic acid-treated monocytes reached maximum levels much earlier than those of control cultures, but the minimum tissue culture infectious doses for retinoic acid-treated and untreated monocytes were comparable. Retinoic acid treatment did not affect susceptibility of monocytes to HIV infection. Further, the frequency of infected cells in retinoic acid-treated and control cultures were also comparable: about 20% of cells in each culture expressed HIV proteins or RNA 2 wk after infection. In contrast, levels of HIV-specific RNA and DNA were 3- to 5-fold higher in the retinoic acid-treated over control monocytes 1 wk after infection. That retinoic acid increased levels of HIV gene expression in monocyte cultures without affecting the number of infected cells per culture suggested a transcriptional mechanism for the effect. This was confirmed in the U937 myeloid cell line transfected with HIV LTR linked to a chloramphenicol acetyl transferase reporter gene. Chloramphenicol acetyl transferase activity in lysates of retinoic acid-treated cells were 20-fold higher than that of control cells. These data show that retinoic acid significantly increased HIV replication in monocytes through mechanisms related to cell differentiation and to a direct transcriptional effect on viral gene expression.

Postpartum femoral neuropathy: relic of an earlier era?

Femoral neuropathy after childbirth is rarely encountered today, although around 1900 an incidence of up to 4.7% was found. A case of postpartum unilateral femoral neuropathy in a 29-year-old primigravida is described. The patient's labor was complicated by poor progression, a prolonged second stage (three hours), and midforceps delivery. The patient received both epidural anesthesia (requiring catheter manipulation) and spinal anesthesia. Total time in the dorsal lithotomy position was four hours; total duration of labor was 27 hours. After delivery, the patient experienced buckling at the right knee and numbness down the leg anteriorly. The electromyogram at one month was consistent with an acute femoral neuropathy. Information about other cases of postpartum lower extremity neuropathy was obtained by a retrospective review of all deliveries at a large maternity hospital between 1971 and 1987. Of 143,019 live births, there were three other cases of postpartum knee extensor weakness (2.8/100,000), five cases of postpartum footdrop (3.5/100,000), and two cases of meralgia paresthetica (1.4/100,000). Although the precise mechanism of injury remains unclear, the declining incidence of femoral neuropathy may reflect decreased duration of labor with modern obstetric practices, particularly more frequent Cesarean delivery.

Pancoast tumor presenting as cervical radiculopathy.

A case of Pancoast tumor presenting as cervical radiculopathy is reported, including the clinical, EMG, and radiologic findings. A 64-year-old man with a two-month history of left shoulder pain and left arm numbness at the medial aspect of the hand and forearm presented for electrodiagnostic examination, and a severe C8 radiculopathy was documented. Subsequent radiologic evaluation (myelogram and routine chest x-ray) yielded the diagnosis of left apical lung tumor (Pancoast tumor), eroding through the C7 and T1 pedicles and T1 vertebral body, with cut-off of the left C8 nerve root. Pancoast tumor has long been implicated as a cause of brachial plexopathy. The EMG presentation of isolated cervical radiculopathy, however, has not been previously reported, despite the tumor's known tendency for local invasion which may include the nerve roots and even the spinal canal in its advanced stages. This patient's normal sensory studies argue against any significant coexisting lower brachial plexopathy. The possibility of Pancoast lesion should be considered not only in the presence of brachial plexopathy, but also when C8 or T1 radiculopathy is found.

A prospective study of peripheral nerve lesions occurring in traumatic brain-injured patients.

The purpose of this study was to determine the frequency and severity of peripheral nerve lesions occurring in patients with traumatic brain injury. A prospective study of 132 patients was conducted. Patients fulfilling research criteria (flaccidity, areflexia, abnormal motor patterns) underwent neurodiagnostic examination. Fifteen electromyograph/NCV studies were performed, yielding positive findings in 13 patients (10%); 3 patients were found to have preventable lesions. Many patients had permanent impairment or attendant complications from the peripheral nerve injury that adversely affected eventual recovery.

Biometrical and chromosome analyses of lines of Drosophila melanogaster selected for central excitation.

Lines of Drosophila melanogaster, bidirectionally selected for extreme and opposite expression of central excitatory state (CES), were subjected first to biometrical and then to chromosome analysis. The analyses revealed that low CES expression is partially dominant to high, at least two chromosomes (II and III) are correlated with CES expression, for the low line, both chromosomes, II and III, are necessary for low expression, cytoplasmic factors are involved with CES expression, and loci of minor effect on the X and Y chromosomes are correlated with CES expression.

Behavioral assessment of lines of Drosophila melanogaster selected for central excitation.

Selected lines of Drosophila melanogaster, bred for high and low levels of central excitatory state (CES), were used in experiments to assess the effects of artificial selection on CES expression and to identify other correlated traits that may have become manifest during selection. Results indicate that the selected lines display (a) different levels of CES, (b) differences in water responsiveness (possibly due to differences in dehydration rates), (c) no water-induced CES, and (d) no significant amounts of sensitization or conditioning. Also, CES in the high line is not dissipated by subsequent posttest stimulations. Comparing the characteristics of CES in Drosophila and in Phormia regina reveals significant species differences. The relevance to earlier P. regina work with respect to CES and conditioning is discussed.

Selection for central excitation in Drosophila melanogaster.

In two populations of Drosophila melanogaster, bidirectional selection and single-pair matings for high and low expression of central excitatory state (CES) succeeded in producing from one a high, but not a low, CES line, and from the other a low, but not a high, CES line. Compared with results from the selection studies of the blow fly, Phormia regina, in which one major gene correlate of CES has been found, the results from this study suggest that in D. melanogaster there are several gene correlates of CES, opposite alleles of some of which have become fixed in the divergent lines.

The reduction of death anxiety: a comparison of didactic, experiential and non-conscious treatments.

This study investigated the effects of three death anxiety reduction techniques on levels of death anxiety and self-actualization. The three techniques were didactic, experiential and non-conscious, with the methods being compared with each other and with a control group. The results indicate that an experiential format is significantly more effective in reducing death-related fears and enhancing psychological integration than are cognitive or non-conscious methods. Possible reasons for such differential effects are discussed.

Normative data for the Spreen-Benton Sentence Repetition Test: its relationship to age, intelligence, and memory.

The present study provided normative data applicable to a cortically-impaired adult population on the Spreen-Benton Sentence Repetition Test. Data were presented for decade groups ranging from 20 to 70 years. The current research indicated that intelligence may play a relatively strong role in performance on this test; also, that memory may be involved, but to a lesser degree. It was recommended that patients' intellectual levels be considered when interpreting the results of the Sentence Repetition Test.

Attribution of control and the fear of death among first-year medical students.

Explored the relationship between attribution of control and the fear of death in a medical student population. Ss were 50 first-year students at the LSU School of Medicine at New Orleans, with a mean age of 24.7 years. Instruments included the Rotter Internal-External Locus of Control Scale and the Templer Death Anxiety Scale. Ss were divided into two groups (internal or external) based upon scores on the Locus of Control Scale, and a one-way analysis of variance was computed between the groups. The dependent variable was level of death anxiety. The results revealed that the internally oriented group obtained a significantly lower mean score on the Death Anxiety Scale when compared to the externally oriented group (F = 2.28, p less than .02). Two additional ANOVAs that used sex and age as the independent variables revealed no significant differences on the death anxiety measure, thus strengthening the apparent relationship between locus of control and fear of death.

Central excitation in the fruit fly (Drosophila melanogaster).

The probability of proboscis extension to a water posttest is increased by prior sucrose stimulation. This phenomenon, termed the central excitatory state (CES), first described in Phormia regina, has now been characterized in Drosophila melanogaster. Drosophila's CES (a) decays over time and (b) is a function of sucrose concentration. THe test for CES also measures water responsiveness, a component of proboscis extension operationally independent of CES. Control experiments confirmed that CES-dependent proboscis extension is not an artifact due to restimulation of sucrose residues and that the neural junctures involved are centrally located.