The locus of origin of augmenting and reducing of visual evoked potentials in rat brain

Humans who are high sensation seekers and cats who demonstrate comparable behavioral traits show increasing amplitudes of the early components of the cortical visual evoked potential (VEP) to increasing intensities of light flash; low sensation seekers show VEP reducing. Roman high-avoidance (RHA) and Roman low-avoidance (RLA) rats have behavioral traits comparable to human and cat high and low sensation seekers, respectively. Previously, we showed that RHA and RLA rats are cortical VEP augmenters and reducers, respectively. The goal of this study was to determine if augmenting-reducing is in fact a property of the visual cortex or if it originates at the lateral geniculate nucleus and is merely reflected in recordings from the cortex. EPs to five flash intensities were recorded from the visual cortex and dorsal lateral geniculate of RHA and RLA rats. As in the previous study, the slope of the first cortical component as a function of flash intensity was greater in the RHA than in the RLA rats. The amplitude of the geniculate component that has a latency shorter than the first cortical component was no different in the two lines of rats. The finding from the cortex confirms the earlier finding of augmenting and reducing in RHA and RLA rats, respectively. The major new finding is that the augmenting-reducing difference recorded at the cortex does not occur at the thalamus, indicating that it is truly a cortical phenomenon.

Radioimmunotherapy of medullary thyroid cancer with iodine-131-labeled anti-CEA antibodies

This study evaluates the pharmacokinetics, dosimetry, toxicity and therapeutic potential of radiolabeled NP-4 and MN-14 anti-CEA antibodies in medullary thyroid cancer (MTC).

METHODS

Eighteen patients with advanced MTC entered exploratory clinical studies with therapeutic doses of 131I-labeled NP-4 and MN-14 murine monoclonal antibodies (MAbs) reactive with carcinoembryonic antigen (CEA). Doses administered ranged from 46 mCi for 131I-MN-14 lgG to 195 mCi for 131I-MN-14 F(ab)2 in patients negative for human anti-mouse antibodies (HAMA).

RESULTS

The radioconjugate blood half-life (T1/2) for the whole lgG was 42.5+/-5.0 hr compared to 18.8+/- 4.1 hr for the bivalent fragments. Tumor doses of 17.5+/-11.0 and 11.4+/-6.3 cGy/mCi were estimated for 131I-MN-14 lgG and F(ab)2, respectively. Tumor/red marrow dose ratios exceeded 3:1 for most lesions. Red marrow doses of up to 350 cGy generally could be delivered with < grade 4 toxicity. Seven of 14 evaluable patients showed evidence of anti-tumor effects lasting up to 26 months, based on physical exam, tumor markers or computed tomography.

CONCLUSION

This study demonstrates that anti-CEA MAbs may be suitable for radioimmunotherapy of metastatic or recurrent MTC.

Improved detection of medullary thyroid cancer with radiolabeled antibodies to carcinoembryonic antigen

PURPOSE

This investigation was undertaken to assess the targeting of established and occult medullary thyroid cancer (MTC) with radiolabeled monoclonal antibodies (MAbs) reactive with carcinoembryonic antigen (CEA).

PATIENTS AND METHODS

Twenty-six assessable patients with known (n = 17) or occult (n = 9) MTC were studied with radiolabeled anti-CEA MAbs. Scintigraphic images were collected to determine targeting of tumor lesions.

RESULTS

The targeting results of technetium 99m (99mTc)-,iodine 123 (123I)-, and iodine 131 (131I)-labeled anti-CEA antibodies (all directed against the same epitope of CEA) indicated that all these reagents were capable of detecting established and occult MTC. The sensitivity for detection of known sites of disease ranged from 76% to 100% for the various anti-CEA MAbs used, when compared with computed tomography (CT), magnetic resonance imaging (MRI), bone scan, or other imaging modalities. Moreover, the antibody scan was positive in seven of nine patients with occult disease (patients with negative conventional imaging studies, but who had elevated calcitonin and/or CEA levels). Three of seven patients underwent surgery and the disease was confirmed by histopathology in all three.

CONCLUSION

Anti-CEA MAbs are excellent agents for imaging recurrent, residual, or metastatic MTC. The high lesion sensitivity in patients with known lesions, combined with the ability to detect disease, may make these agents ideal for staging patients, monitoring disease pretherapy or posttherapy, and especially for evaluating patients with recurrent or persistent hypercalcitonemia or CEA elevations after primary surgery. Analogous to radioiodine in the evaluation of patients with differentiated thyroid cancer, radiolabeled anti-CEA MAbs may achieve a similar role in diagnosing and monitoring patients with MTC.

Recent developments in an animal model of visual evoked potential augmenting/reducing and sensation seeking behavior

The early research on an animal (cat) model and biological marker (visual evoked potential augmenting and reducing) of sensation seeking behavior is briefly described. Recent findings with selectively bred lines of rats show that (1) the relationship between sensation seeking behavior and augmenting vs. reducing is also present in the rat; (2) augmenting and reducing is a cortical, not a subcortical, phenomenon, and (3) augmenting/reducing and related sensation seeking behaviors are heritable traits. This paper also discusses evidence for the relative contributions of genetic and environmental factors in determining the sensation seeking trait.

Targeting and initial radioimmunotherapy of medullary thyroid carcinoma with 131I-labeled monoclonal antibodies to carcinoembryonic antigen

The targeting potential of 131I-labeled NP-4 and MN-14 anti-CEA (carcinoembryonic antigen) monoclonal antibodies (MAbs) was assessed in 19 patients with metastatic medullary thyroid cancer (MTC). Seventeen of these patients also entered pilot radioimmunotherapy studies with nonmyeloablative doses of 131I-anti-CEA MAbs. Tumor targeting was possible in all 19 patients, with an overall lesion sensitivity of 91%. Tumor dosimetry with 131I-MN-14 IgG or F(ab)2 was very favorable, with tumor doses of 14.3 +/- 8.3 cGy/mCi and tumor:red marrow dose ratios exceeding 3:1 for most lesions. Limited antitumor effects lasting up to 26+ months, based on physical exam, tumor markers, computed tomography, or a followup MAb scan, were seen in 5 of 11 assessable patients given relatively low doses of 131I-labeled anti-CEA MAbs. We conclude that anti-CEA MAbs are excellent agents for targeting metastatic MTC. The high tumor uptake of the 131I-anti-CEA antibodies and evidence of tumor response in some patients suggest that radioimmunotherapy with radioiodinated anti-CEA MAbs may be an effective treatment for MTC, particularly when the maximum tolerated dose is given alone or in combination with autologous red marrow or peripheral stem cell support.

Enhanced p53 activity and accumulation in response to DNA damage upon DNA transfection

In response to DNA damage the wild-type tumor suppressor protein p53 accumulates in the nucleus of rodent and primate cells. To investigate the minimal requirement for this reaction the cellular DNA was restricted by two alternative ways: (i) by calicheamicin gamma 1, an enediyne, which causes direct, sequence-specific DNA damage, as shown by fluorimetric analysis of DNA unwinding and by poly(ADP-ribose) polymerase activation. The dose-dependent DNA damage correlated with the nuclear p53 accumulation. In addition, restriction was generated (ii) by the intracellular introduction of the restriction enzyme PvuII, which generates blunt-ended DNA breaks, applying a mild hypotonic shock (pellet method). Previous transfection of linear or circular, single- or ds, DNA, followed by mitomycin C-treatment, lead to a dramatic increase in nuclear p53 accumulation and p53 activity according to electrophoretic mobility shift analysis. The nature of transfected DNA was irrelevant for enhanced accumulation. The data suggest, that the cellular p53 response to DNA damage is sensitized by uptake of exogenous DNA.

Differential categorization of words by learning disabled, gifted, and nonexceptional students

This research was done to answer whether learning disabled students attend to different word features than nonexceptional and gifted students and whether there is a difference by grade. Word sorts of meaningful and nonsense words were used to estimate differences between 145 first- and fifth-grade learning disabled, nonexceptional, and gifted groups. Analyses indicated that 54 learning disabled students were more likely to provide no response or to give simpler responses than 61 nonexceptional or 30 gifted peers. Older children (n = 78) attended to more and varied word features, were more likely to focus on recognizable meaning, and were more able to use syllables as a tool for sorting than were 67 younger children. Significant differences were noted between grade and exceptionality groups. Implications for practical application and further research are discussed.

Altered distribution of cholinergic cells in the narcoleptic dog

Narcolepsy is characterized by excessive sleepiness and episodes of cataplexy brought on by emotional excitation. Cataplexy and sleep paralysis have been hypothesized to be produced by the triggering during waking of brain stem cholinergic mechanisms normally acting to induce atonia in REM sleep. We hypothesized that narcoleptics have an abnormal number of LDT and/or PPN cholinergic neurons. A comparison was made of cholinergic cell numbers in the brain stems of normal and narcoleptic canines. Cholinergic neurons were identified by NADPH-diaphorase histochemistry. We found increased numbers of cholinergic neurons at the R6-R7 level of the LDT and PPN in narcoleptic canines. This abnormality can explain alterations in cholinergic receptor number, acetylcholine release, and the occurrence of cataplexy and sleep paralysis that characterize narcolepsy.

Assessment of microbial growth in intravenous immune globulin preparations

The ability of intravenous immune globulin (IVIG) products to support bacterial and yeast growth was studied. Microtiter plates containing preparations of eight commercially available IVIG products were inoculated with 10(5) colony-forming units (CFUs) of bacteria per milliliter or 10(3) CFUs of yeast cells per milliliter. The organisms used were Candida albicans, Torulopsis glabrata, Pseudomonas aeruginosa, Staphylococcus epidermidis, and Klebsiella pneumoniae. The plates were incubated at 3, 25, or 37 degrees C for seven days. For each organism and each temperature, a total of 16 identical wells were studied per preparation. Optical density was measured at 24-hour intervals to determine bacterial growth; yeast growth was determined visually. None of the IVIG preparations supported bacterial growth at any temperature over the seven-day period. No preparation supported visible yeast growth at 3 degrees C; however, most of the preparations did support yeast growth at 25 and 37 degrees C. The failure of the IVIG preparations to support bacterial growth at all temperatures and yeast growth at 3 degrees C suggests that a reconsideration of recommended expiration dates for IVIG products may be warranted.

Endoscopic ultrasonographic criteria of vascular invasion by potentially resectable pancreatic tumors

Endoscopic ultrasonography was used to examine 38 patients with a pancreatic neoplasm (mean size, 2.8 cm; range, 1 to 5 cm). Three EUS signs appear to be reliable criteria for the identification of tumor invasion of major veins forming the portal confluence: (1) peri-pancreatic venous collaterals in the area of a mass that obliterates the normal anatomic location of a major portal confluence vessel; (2) tumor within the vessel lumen; and (3) abnormal vessel contour with loss of the vessel-parenchymal sonographic interface. At least one of these signs was present in each of the 21 patients with vascular invasion; none of them was present in the 17 patients without vascular invasion. Findings were confirmed by laparotomy plus biopsy (33 patients), autopsy (1 patient), or angiography plus biopsy (4 patients). Arterial involvement was identified by alteration of vessel course and caliber. All 7 patients with arterial involvement also had venous involvement. These signs provide reliable criteria for endoscopic ultrasonographic definition of unresectable tumors in patients with a pancreatic neoplasm that appears to be resectable on standard radiologic tests.

Augmenting and reducing of visual evoked potentials in Roman high- and low-avoidance rats

Human and cat high sensation seekers tend to show increasing amplitudes (augmenting) of the P1 and N1 components of the visual evoked potential (VEP) to increasing intensities of light flash, whereas low sensation seekers show VEP reducing. Roman high-avoidance (RHA) and Roman low-avoidance (RLA) rats have behavioral traits comparable to human and cat high and low sensation seekers, respectively. RHA rats show greater exploration, activity, and aggression than do RLA rats. Rats of each Roman line and Wistar rats were anesthetized with chloral hydrate and maintained at a stable moderate anesthetic level. VEPs to each of five flash intensities were computer averaged for each rat. The slopes of P1 amplitudes as a function of flash intensity were significantly greater in the RHA than the RLA rats. RHA rats were clear augmenters; RLA rats had almost flat amplitude-intensity functions. The Wistar rats had slope functions that were similar to those of the RLA rats. This study shows that the relationship between sensation-seeking behavior and VEP augmenting and reducing has a heritable base and extends across species from human, cat, and rat. In addition, we demonstrate a rat model of this relationship that yields advantages of genetic homogeneity and a short generational time, and provides access to a wealth of behavioral data and experimental manipulations available for the rat.

Formation of antisperm antibodies in women treated with fallopian tube sperm perfusion

Fallopian tube sperm perfusion (FSP) is a combination of ovarian stimulation and intra-uterine insemination using a large volume (4 ml) of inseminate containing 10(7)-10(8) spermatozoa. The inseminate will flush the Fallopian tubes and some of it will end up in the pouch of Douglas. In the present study, we have investigated whether the FSP method will result in the formation of serum antisperm antibodies in the female. A total of 184 treatment cycles were given to 128 women. The indications for treatment were: unexplained infertility (n = 35), various infertility diagnoses (n = 28) and donor insemination (n = 65). Prior to treatment, 11 (8.6%) women had a positive tray-agglutination test (Friberg) and/or a positive immunobead test. After completing one to four treatment cycles, another six (4.7%) women had developed serum antisperm antibodies. The antibodies induced by the treatment were of isotype IgM and directed against the tail-tip of the spermatozoa. Two of the women, who prior to the treatment had antisperm antibodies, showed an increase in antibody titre during treatment. There was no statistically significant difference in the pregnancy rate between the women with antisperm antibodies and the women without. In our opinion, the small risk of developing antisperm antibodies is no contra-indication for treating infertile couples with FSP.

Low versus high density of immobilized anti-CD3 influences IL-4 regulation of T-cell immune responses

Varying the concentration of anti-CD3 immobilized on Sepharose beads allowed us to study both the inhibitory and the stimulatory effects of IL-4 on purified T cells and contrast IL-4 versus IL-2-driven T-cell proliferative responses. In the presence of low density immobilized anti-CD3, IL-4 was unable to stimulate purified T cells and was inhibitory to IL-2-driven T-cell responses. The inhibitory effects of IL-4 were enhanced by preincubation of T cells with IL-4 prior to stimulation. In contrast, the inhibitory effects of IL-4 could be avoided by delaying the addition of IL-4 until Days 3-5 of culture or they could be reversed by the addition of IL-1. In the presence of high-density anti-CD3, IL-4 elicited an IL-2-independent proliferative response by purified T cells or sorted CD8+ cells. Comparison of IL-4-driven versus IL-2-driven T-cell responses demonstrated that IL-2 was able to upregulate mRNA for IL-4 receptors and interferon-gamma, while IL-4 had minimal effects on upregulating mRNA for either the p55 or the p75 IL-2 receptor subunits or interferon-gamma. The timing of the presence of IL-4, the state of T-cell activation, and the nature and strength of the stimulatory signal influenced the regulatory effect of IL-4 on the immune response.

The toxicity of daily inhaled amphotericin B

Inhaled amphotericin was administered to 29 patients with prolonged neutropenia and toxicity was analyzed. Treatment consisted of 30 mg of amphotericin B administered by nebulizer once daily via either a hand-held nebulizer or face mask. The mean duration of treatment was 16 days. Toxicity was minimal and patient had significant toxic reaction to the inhaled medication. This study documents that nebulized amphotericin B has less than 10% incidence of severe toxicity with 95% confidence level. Guidelines for future trials and use are suggested.