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Biomedical subjects

B Gordon

Publications and source records attributed to B Gordon.

At least 163 records · Page 9Linked to original sources
PubMed1983

Closed- and open-class lexical access in agrammatic and fluent aphasics.

Bradley, Garrett, and Zurif (Bradley, Computational distinctions of vocabulary type. Unpublished doctoral dissertation, MIT Press; Cambridge, MA, 1978; Biological studies of mental processes, MIT Press, Cambridge, MA, 1980) have suggested that closed-class word access is normally mediated by a different route than the open-class one, and that the loss of this closed-class route might account for agrammatism. However, in an earlier study (Gordon & Caramazza, Brain and Language, 15, 143-160, 1982) we were not able to confirm a meaningful difference between closed- and open-class word frequency responsiveness of the type Bradley (unpublished dissertation, 1978) had seemed to find in normal subjects. We have now done a direct comparison of closed-class frequency sensitivity in agrammatic and nonagrammatic aphasics, to directly test Bradley and colleagues' hypotheses and to avoid some of the experimental problems with between-class frequency comparisons. We find that closed-class words behave similarly whether or not the subject is agrammatic. Therefore, the differences between agrammatic and nonagrammatic aphasics must arise at a deeper level (or levels) of lexical processing than the one probed by the frequency sensitivity effect.

Aphasia↗
PubMed1983

Increased respiratory chemosensitivity induced by infusing almitrine intravenously in healthy man.

The respiratory effects of intravenously infused almitrine were evaluated in healthy volunteers. In the dose range 0.25-1.0 mg/kg/hour it caused large and dose-dependent increases in hypoxic chemosensitivity, which were longlasting and more persistent than the drug's retention in the plasma. Increases in sensitivity to hypercapnia were much less and were detected only when the plasma almitrine exceeded 200 ng/ml. Small increases in resting ventilation and metabolic rate with a decrease in mixed venous carbon dioxide tension occurred only at the highest infusion rate. The findings accord with an action of almitrine in the peripheral chemoreceptors, which may be of therapeutic value in managing some cases of respiratory failure.

Adult↗
PubMed1983

Effect of eye rotation on visual-field map onto superior colliculus and visual cortex.

We used multiunit recording to assess the effect of rotating one eye approximately 90 degrees at about the time of normal eye opening. Rotation of the eye did not alter the topography of the retinal maps onto visual cortex or superior colliculus. The intorted eye drove cells at most recording points in the contralateral visual cortex and superior colliculus. In its ipsilateral colliculus the intorted eye drove cells at about 10% of the recording points; that is, the temporal retina of this eye was quite ineffective in driving collicular cells. In its ipsilateral cortex the intorted eye drove cells at about 30% of the recording sites. The unoperated eye drove cells at all locations in both colliculus and cortex on both sides of the brain. The effects of extorsion were studied only in the superior colliculus. Extorsion and intorsion produced similar results except that extorsion produced a less severe deficit in the ability of the temporal retina to drive cells in its ipsilateral colliculus. Cutting all the extraocular muscles without eye rotation was studied only in the colliculus and produced results similar to those produced by intorsion and extorsion. However, the temporal retina of the operated eye was more effective after muscle cut alone than after intorsion or extorsion. Forcing the animal to use the rotated right eye alone on alternate days during the first 3 mo of life did not decrease the deficits. Almost all recording sites in the right colliculus were driven only by the unoperated left eye. If the left eye was sutured when the right eye was rotated, only the right eye drove cells in the left colliculus, but the two eyes were about equally effective in the right colliculus; however, rather few sites in the right colliculus were binocularly driven. We conclude that both extraocular muscle section and eye rotation reduce the effectiveness of the uncrossed input from the operated eye to the superior colliculus and visual cortex. The effects on the superior colliculus are, however, greater.

Animals↗
PubMed1983

Effects of eye rotation on visually guided behavior.

Visually guided behavior was examined in cats reared with one eye intorted, one eye extorted, or monocular section of the extraocular muscles. Kittens from 2 to 4 mo old jumped from a tower onto a platform in a pan of water. They refused to jump or missed the platform more often when forced to use the rotated eye than when forced to use the unoperated eye. This deficit was eliminated if the non-rotated eye was sutured at the time of eye rotation. Further, when the extraocular muscles were cut but the eye was not rotated, jumping was normal. Acuity was measured using an alley box in which the cats were required to distinguish between horizontal and vertical stripes. No cats were blind when tested with the operated eye. Although not conclusive, the data suggest that the acuity of the rotated eye was slightly lower than that of the unoperated eye. The visual field of the rotated eye was also abnormal. Regardless of the direction of eye rotation, the cats appeared blind in the contralateral and lower visual quadrants. This field deficit was much less severe in animals with extraocular muscle section alone and did not occur in rotation-plus-suture animals. The visual-field deficits in the contralateral field can be explained by assuming that each collicular or cortical region always controls orienting to the same region of the visual field. We are, however, unable to explain the deficits in the lower field in terms of the mapping data from the previous paper (4).

Animals↗
PubMed1983

Generalized lymphadenopathy in homosexual men.

The cases of 90 homosexual or bisexual men with generalized lymphadenopathy were studied by epidemiologic, clinical, pathologic, immunologic, and genetic methods. The patients ranged in age from 20 to 52 years and had histories of multiple sexually transmitted diseases and both recreational and prescription drug use. Histologically, their lymph nodes showed three patterns: explosive follicular hyperplasia; follicular involution with expansion of the paracortical area; and a mixed pattern of follicular hyperplasia and follicular involution in the same lymph node. The frequency of HLA-DR5 was significantly increased in these patients (p less than 0.005) compared with that in controls. All patients had impaired cell-mediated immunity. Opportunistic infections, lymphomas, or Kaposi's sarcoma subsequently developed in 15 patients who had had severe immune dysfunction for the previous 3 to 13 months. We suggest that generalized lymphadenopathy is part of the spectrum of a disorder manifested by acquired immunodeficiency, opportunistic infections, Kaposi's sarcoma, and malignant lymphomas.

Adult↗
PubMed1983

Effect of retinoic acid on the growth and morphology of a prostatic adenocarcinoma cell line cloned for the retinoid inducibility of alkaline phosphatase.

Cells derived from the G-subline of the Dunning R-3327 rat prostatic adenocarcinoma were selected on the basis of their inducibility for alkaline phosphatase (AP) activity by retinoic acid. A p-nitrophenylphosphate-agarose overlay procedure was used to identify AP-inducible clones. The frequency of AP-inducible cells in one rapidly growing tumorigenic clone, designated 9-1C, has remained at 100% during at least 4 months of continuous culture. In culture, 9-1C cells had a mean population-doubling time in log phase of 14 hr. Retinoic acid (10 microM) did not significantly affect the rate of growth in log phase. It did, however, cause the cultures to saturate at a cell density which was 40% lower than that of control cultures. This effect on saturation density was reversible within 24 hr after removing retinoic acid from the medium. Retinoic acid-treated cells occupied greater areas on the culture dish surface, and the cross-sectional area of these cells, measured on dispersed cells by light-scatter flow cytometry, was 35 to 40% greater than that of control cells. The inducibility of 9-1C cells for AP activity decreased as the culture density increased. Cells of the 9-1C clone produced tumors when injected into male and female Fischer X Copenhagen F1 rats. No histological differences were detected between tumors grown in male and female rats. Although the tumors were poorly differentiated, primitive acinar-like structures were observed. Cells staining uniformly positive for AP activity were distributed randomly throughout the tumors. In the acinar-like structures, AP activity was localized only on the apical surfaces of the cells lining the lumens. This was also the site of enzyme activity in acini of the lateral component of the dorsolateral prostate, the source of the original R-3327 tumor. In the lateral prostatic component, AP activity was also found in the basal region of the acini, and the secretory material filling the lumens was strongly positive for the enzyme. These two regions of the tumor acini were negative for AP activity. With the exception of activity in capillaries at the basal surface, the acini of the dorsal component of the dorsolateral prostate were devoid of AP activity.

Adenocarcinoma↗
PubMed1982

Continuous infusion vincristine and bleomycin with high dose methotrexate for resistant non-Hodgkin's lymphoma.

Sixteen patients with resistant non-Hodgkin's lymphoma were treated with continuous infusions of vincristine (1-2 mg/m2 daily X 2 days) and bleomycin (0.25 mg/kg bolus dose, then 0.25 mg/kg/daily X 5 days). Responding patients received high dose methotrexate (1500 mg/m2) with citrovorum rescue on days 15, 22, 29, 36. Treatment cycles were repeated every six weeks in responding patients. The response frequency was 50% (three complete and five partial responses). Median response duration was 29 weeks. Major toxicity included stomatitis (63%) and leukopenia (44%). One episode each of possible hypersensitivity pneumonitis and paralytic ileus occurred. Continuous infusions of vincristine and bleomycin should be studied further in less critically ill patients.

Adult↗
PubMed1982

Orientation deprivation in cat: what produces the abnormal cells?

When an animal is reared with goggles containing stripes of a single orientation, many cells in the visual cortex become abnormal. To find out whether these abnormal cells result from orientation deprivation per se or from other features of goggle rearing we reared kittens with goggles containing stripes of many orientations. The data suggest that orientation deprivation contributes to the development of abnormal cells but is not its sole cause.

Animals↗
PubMed1982

Long term visual deprivation in a human.

D.C. had a congenital monocular cataract removed at 19 years of age. Preoperatively, he was virtually blind in the deprived eye. By 4 months after surgery he could resolve about 1.4 c/deg by acuity did not improve further over the next 7 months. Immediately postoperatively, the temporal retina was blind, but over the next 4 months its visual field increased to 20. The temporal retina continued, however, to have elevated thresholds. D.C. also exhibited a peculiar form of binocular competition. Thresholds of the deprived binocular portions of the nasal retina were greatly elevated by light falling on the non-deprived eye. Visual function in the non-deprived eye was normal.

Adolescent↗
PubMed1981

Interferon-mediated inhibition of mouse mammary tumour virus (type B) and mouse leukaemia virus (type C) in the same culture.

The sensitivity of mouse mammary tumour virus (MMTV) and murine leukaemia virus (MuLV) to interferon was tested by investigating the effect of interferon in cultures of mouse mammary tumour cells simultaneously synthesizing the two viruses. The dose-response curves showed that the extracellular production of both viruses by these cells was equally inhibited by interferon treatment. In contrast, the intracellular steady-state concentration of virus-specific RNA of both MMTV and MuLV was not significantly affected in these cells. This was the case regardless of whether total cellular RNA or polysomal poly(A)-containing RNA was examined. These results are consistent with the suggestion that interferon-caused inhibition is related to a host-mediated effect on a post-transcriptional step in virus synthesis.

Animals↗