Frontal and frontoparietal injury differentially affect the ipsilateral corticospinal projection from the nonlesioned hemisphere in monkey (Macaca mulatta).

Upper extremity hemiplegia is a common consequence of unilateral cortical stroke. Understanding the role of the unaffected cerebral hemisphere in the motor recovery process has been encouraged, in part, by the presence of ipsilateral corticospinal projections (iCSP). We examined the neuroplastic response of the iCSP from the contralesional primary motor cortex (cM1) hand/arm area to spinal levels C5-T1 after spontaneous long-term recovery from isolated frontal lobe injury and isolated frontoparietal injury. High-resolution tract tracing, stereological, and behavioral methodologies were applied. Recovery from frontal motor injury resulted in enhanced numbers of terminal labeled boutons in the iCSP from cM1 compared with controls. Increases occurred in lamina VIII and the adjacent ventral sectors of lamina VII, which are involved in axial/proximal limb sensorimotor processing. Larger frontal lobe lesions were associated with greater numbers of terminal boutons than smaller frontal lobe lesions. In contrast, frontoparietal injury blocked this response; total bouton number was similar to controls, demonstrating that disruption of somatosensory input to one hemisphere has a suppressive effect on the iCSP from the nonlesioned hemisphere. However, compared with controls, elevated bouton numbers occurred in lamina VIII, at the expense of lamina VII bouton labeling. Lamina IX boutons were also elevated in two frontoparietal lesion cases with extensive cortical injury. Because laminae VIII and IX collectively harbor axial, proximal, and distal motoneurons, therapeutic intervention targeting the ipsilateral corticospinal linkage from cM1 may promote proximal, and possibly distal, upper-limb motor recovery following frontal and frontoparietal injury.

Vulnerability of the medial frontal corticospinal projection accompanies combined lateral frontal and parietal cortex injury in rhesus monkey.

Concurrent damage to the lateral frontal and parietal cortex is common following middle cerebral artery infarction, leading to upper extremity paresis, paresthesia, and sensory loss. Motor recovery is often poor, and the mechanisms that support or impede this process are unclear. Since the medial wall of the cerebral hemisphere is commonly spared following stroke, we investigated the spontaneous long-term (6 and 12 month) effects of lateral frontoparietal injury (F2P2 lesion) on the terminal distribution of the corticospinal projection (CSP) from intact, ipsilesional supplementary motor cortex (M2) at spinal levels C5 to T1. Isolated injury to the frontoparietal arm/hand region resulted in a significant loss of contralateral corticospinal boutons from M2 compared with controls. Specifically, reductions occurred in the medial and lateral parts of lamina VII and the dorsal quadrants of lamina IX. There were no statistical differences in the ipsilateral CSP. Contrary to isolated lateral frontal motor injury (F2 lesion), which results in substantial increases in contralateral M2 labeling in laminae VII and IX (McNeal et al. [2010] J. Comp. Neurol. 518:586-621), the added effect of adjacent parietal cortex injury to the frontal motor lesion (F2P2 lesion) not only impedes a favorable compensatory neuroplastic response but results in a substantial loss of M2 CSP terminals. This dramatic reversal of the CSP response suggests a critical trophic role for cortical somatosensory influence on spared ipsilesional frontal corticospinal projections, and that restoration of a favorable compensatory response will require therapeutic intervention.

High prevalence of syphilis-HIV co-infection at four hospitals of the city of Buenos Aires, Argentina.

A cross-sectional anonymous study of 261 STD (sexually transmitted diseases) outpatients and 288 outpatients from other hospital departments was conducted at four major city hospitals in Buenos Aires. High prevalence of human immunodeficiency virus (HIV) (14.5%) and syphilis (30.2%) was noted. Fifty-two persons were diagnosed with both HIV and syphilis. Of the 87 HIV cases observed, 52 (59.7%) were co-infected with syphilis. Stratified analysis by gender showed that the prevalence of HIV, syphilis and HIV/syphilis co-infection was significantly (p < 0.001) higher in men than women (HIV: 20.1% vs. 4.6%; syphilis: 39.3% vs. 17.4%; co-infection: 13.6% vs. 1.7%). Integrated HIV/STD intervention programs and more effective surveillance are required in Argentina.

A coordinate system for visual motion perception.

The purpose of this research was to determine the reference axes used by the visual system to specify direction of motion of objects by the visual system at the perceptual level. Ten young adults aligned motion of a moving luminous dot on a computer display to body-fixed and external vertical and horizontal plane axes while operating in a dark room. Accuracy of aligning dot motion to earth-fixed vertical, a displayed luminous line (external visual axis) of varied orientations, and head and trunk longitudinal axes was tested in one experiment with the display in the vertical frontal plane. In a second experiment, dot motion was aligned to head and trunk anterior/posterior (A-P) axes and to an external visual axis presented on a horizontal computer screen. Head and trunk orientations were varied in the frontal plane (left/right tilt) when testing vertical plane axes and by rotation of the head and/or trunk about a vertical axis when testing horizontal plane axes. Perceptual errors were lowest when aligning to earth-fixed vertical in the vertical plane and to an external oblique line in the horizontal plane when head and trunk orientations were varied. Perceptions of horizontal plane motion direction were accurate relative to the trunk-fixed A-P axis when only head orientation was varied, but large errors were made when trunk orientation was varied. Proprioceptive influences on visual perceptions of motion direction were shown by a dependence of perceptual errors on trunk and neck orientations when aligning to all axes. Furthermore, when aligning motion to an external line, the errors depended on orientation of the line in addition to trunk and neck orientations, but not when aligning to intrinsic axes or earth-fixed vertical in the presence of an external line. We conclude that the visual motion system defines direction relative to earth-fixed vertical and an external horizontal reference axis when available. The trunk-fixed A-P axis can be used to accurately define motion direction when operating without an external reference if a neutral trunk orientation is maintained.

[Syphilis and pregnancy. Prenatal control, seroprevalence and false biological positives]. / Sifilis y embarazo. Control prenatal, seroprevalencia y falsos biológicos positivos.

Syphilis may be transmitted vertically, especially if the mother is in an early stage with a high bloodstream treponema concentration, although it may also be transmitted to a lesser degree in late latency, when non-treponemic serology may become negative spontaneously with persistence of treponemic serology. The prenatal control for syphilis is routinely carried out by means of a non-treponemic reaction such as VDRL or rapid plasma reagin (RPR) which, when positive, should be confirmed by treponemic techniques such as fluorescent treponemal antibody absorption (FTA-abs) and/or hemagglutination (MHA-Tp). Prevalence of syphilis should be defined on the basis of positive treponemic reactions. To define the seroprevalence and the validity of these control guidelines, 1,056 pregnant women attending the Hospital de Clínicas for their initial control were evaluated by means of serological treponemic and non-treponemic methods. Serological results disclosed 4 distinct groups. Group 1 (n = 17 or 1.61%) presented both types of reactive tests, while Group II (n = 22 or 2.08%) only presented reactive treponemic tests, and both groups were seroreactive for syphilis. Group III (n = 7 or 0.66%) only showed reactive non-treponemic tests, which were considered biological false-positive (BFP) reactions. Five of them were reactive for antiphospholipid antibodies. Group IV (n = 1,010 or 95.65%) fell to present serological evidence of syphilis. To conclude: 1) global seroprevalence in this population was 3.69%; 2) since 2.08% of pregnant seroreactive mothers had not been detected by routine screening, it would be advisable to perform simultaneous treponemic and non-treponemic techniques for prenatal control. 3) This methodology should identify the BFP tests in the same screening.

Sifilis y embarazo. Control prenatal, seroprevalencia y falsos biológicos positivos. / [Syphilis and pregnancy. Prenatal control, seroprevalence and false biological positives]

Syphilis may be transmitted vertically, especially if the mother is in an early stage with a high bloodstream treponema concentration, although it may also be transmitted to a lesser degree in late latency, when non-treponemic serology may become negative spontaneously with persistence of treponemic serology. The prenatal control for syphilis is routinely carried out by means of a non-treponemic reaction such as VDRL or rapid plasma reagin (RPR) which, when positive, should be confirmed by treponemic techniques such as fluorescent treponemal antibody absorption (FTA-abs) and/or hemagglutination (MHA-Tp). Prevalence of syphilis should be defined on the basis of positive treponemic reactions. To define the seroprevalence and the validity of these control guidelines, 1,056 pregnant women attending the Hospital de Clínicas for their initial control were evaluated by means of serological treponemic and non-treponemic methods. Serological results disclosed 4 distinct groups. Group 1 (n = 17 or 1.61

) presented both types of reactive tests, while Group II (n = 22 or 2.08

) only presented reactive treponemic tests, and both groups were seroreactive for syphilis. Group III (n = 7 or 0.66

) only showed reactive non-treponemic tests, which were considered biological false-positive (BFP) reactions. Five of them were reactive for antiphospholipid antibodies. Group IV (n = 1,010 or 95.65

) fell to present serological evidence of syphilis. To conclude: 1) global seroprevalence in this population was 3.69

; 2) since 2.08

of pregnant seroreactive mothers had not been detected by routine screening, it would be advisable to perform simultaneous treponemic and non-treponemic techniques for prenatal control. 3) This methodology should identify the BFP tests in the same screening.

[The impact of HIV infection on the incidence of syphilis and gonorrhea at a university hospital (1985-1994)]. / El impacto del HIV sobre la incidencia de sífilis y gonorrea en un Hospital Universitario (1985-1994).

Syphilis and gonorrhea are two sexually transmitted diseases (STD) which still persist in spite of the existence of effective treatment. In this paper the incidence of these two diseases was evaluated between 1985-1994, a decade during which the problem of HIV infection arose. Every patient who attended the STD Program at the Hospital and was suspected of having syphilis and/or gonorrhea was clinically evaluated and was subjected to the following tests: a) search for Neisseria gonorrhoeae (Ng) and penicinilase producers (PPNG) identification, b) search for Treponema pallidum (Tp) by darkfield microscopy, c) serological studies for syphilis. From 1985 to 1991 the average of positive cases for Ng was 14.8% while from 1992 to 1994 it was 4.0% (p < 0.0001) showing a dramatic decrease between 1991 and 1992. PPNG increased from 8.7% in 1985 to 44.6% in 1988 and then slowly decreased down to 26.9% in 1994. From 1985 to 1990 the average of positive darkfield examinations was 20.7% while from 1991 to 1994 it was 12.2% (p < 0.0001). Between 1985 to 1988 syphilis serological studies showed 45.7% positive cases dropping to 34.3% between 1989 and 1994 (p < 0.0001). HIV infection appearance had a wide repercussion throughout the world generating behavioral and sexual habit changes which have probably helped to prevent these two STD. Gonorrhea incidence was also influenced by the appearance of new effective treatments, even against PPNG, such as fluorated quinolones and third generation cephalosporines. The population studied belongs to the most crowded area in Argentina, so that these observations should not be extrapolated to the rest of the country.

Mechanical analysis of the Nautilus leg curl machine.

The present study assessed the capability of the Nautilus leg curl machine to reflect changes in the isokinetic resistance torque offered to the user commensurate with the human torque pattern generated by the knee flexor muscle group. An averaged isokinetic torque pattern was determined from the exercise machine and from a subject pool (N = 20) of physically active men performing prone knee flexion at two angular velocities (30 degrees/s and 60 degrees/s). The torque patterns of the exercise machine and the subject pool were expressed mathematically. Analysis of the linear regression coefficients established that the resistance torque pattern of the exercise machine was not similar to that of the subject pool (p less than .001). It was concluded that the present exercise machine system did not adequately alter the weight-stack load to provide a resistive torque suited to the biomechanical capabilities of the knee flexors under the two isokinetic conditions studied.

Isolation of fetal DNA from nucleated erythrocytes in maternal blood.

Fetal nucleated cells within maternal blood represent a potential source of fetal genes obtainable by venipuncture. We used monoclonal antibody against the transferrin receptor (TfR) to identify nucleated erythrocytes in the peripheral blood of pregnant women. Candidate fetal cells from 19 pregnancies were isolated by flow sorting at 12 1/2-17 weeks gestation. The DNA in these cells was amplified for a 222-base-pair (bp) sequence present on the short arm of the Y chromosome as proof that the cells were derived from the fetus. The amplified DNA was compared with standardized DNA concentrations; 0.1-1 ng of fetal DNA was obtained in the 20-ml maternal samples. In 7/19 cases, a 222-bp band of amplified DNA was detected, consistent with the presence of male DNA in the isolated cells; 6/7 of these were confirmed as male pregnancies by karyotyping amniocytes. In the case of the female fetus, DNA prepared from samples at 32 weeks of gestation and cord blood at delivery also showed the presence of the Y chromosomal sequence, suggesting Y sequence mosaicism or translocation. In 10/12 cases where the 222-bp band was absent, the fetuses were female. Thus, we were successful in detecting the Y chromosomal sequence in 75% of the male-bearing pregnancies, demonstrating that it is possible to isolate fetal gene sequences from cells in maternal blood. Further refinement in methodology should increase sensitivity and facilitate noninvasive screening for fetal gene mutations.

Effects of complement depletion in experimental chagas disease: immune lysis of virulent blood forms of Trypanosoma cruzi.

In mice infected with virulent blood (trypomastigote) forms of Trypanosoma cruzi, complement depletion with cobra venom factor caused a marked exacerbation of the disease evidenced by significantly increased parasitemia levels and early mortality as compared with those of untreated infected animals. The effect was greater in mice receiving cobra venom factor on day 7 postinfection, i.e., at the time when the parasites had had time to localize and multiply in the tissues and appeared in the circulation in appreciable numbers. The possibility that complement participates in host defense against T. cruzi infection through a mechanism involving immune lysis was explored in vitro. T. cruzi trypomastigotes were found to undergo immune lysis in sera of patients with chronic Chagas' disease, in sera of immunized mice, and in solutions containing both immune mouse gamma globulin and a source of active complement. This phenomenon failed to take place either in the absence of complement or after complement inactivation by heat or utilizing complement inactivators. The lytic capacity of heated sera was restored by the addition of active complement to the system. During the immune lysis of T. cruzi blood forms, complement was activated in human sera via both the classical and the alternate pathways. In mouse sera, activation followed at least the alternate pathway.