PubMed Health⌕ Search

Biomedical subjects

D Friedman

Publications and source records attributed to D Friedman.

16 recordsLinked to original sources
PubMed1979

A brain event related to the making of a sensory discrimination.

Event-related potentials associated with detected targets in a vigilance task were analyzed in two ways: (i) by sorting the potentials in terms of sequential reaction time bins of 50 milliseconds and (ii) by examining the single trial waveforms. A negative component (N2) covaried in latency with reaction time. These results support the hypothesis that N2 reflects a decision process which controls behavioral responses in sensory discrimination tasks.

Behavior↗
PubMed1979

The government and the inguinal hernia.

Our review of the incidence of inguinal hernias in children based on socioeconomic differences and their risk of incarceration with its subsequent complications, was prompted by a governmental decision to disallow elective herniorrhaphy in children over 1 yr of age. The review showed the following: The risk of incarceration, the failure of preoperative reduction and the potential gonadal injury is more than three times as high in the poor child, usually covered by Medicaid. Since operative and postoperative complications increase proportional to the incidence of incarcertain, the denial of an elective herniorrhaphy endangers the life of a child. Since the increased hospitalization after incarceration also increases the financial expenditure, this rule is not only medically but also economically unsound. This review suggests that unilateral governmental health care decisions, especially those aimed at cost containment, should be carefully scrutinized to determine what price not only the society, but the patient has to pay for the "cost containment". We feel that the price of the denial of a herniorrhaphy is too high.

Child↗
PubMed1978

Stimulus and response related components of the late positive complex in visual discrimination tasks.

Visual event-related potentials (ERP) were recorded from 6 subjects aged 10--15 in response to target stimuli in 2 vigilance tasks which differed in their processing requirements. Stimulus- and response-synchronized averages were computed for each subject for each quartile (Q) of that subject's reaction time (RT) distribution. Late positive complexes (LPC) of identical morphology were seen in the brain potentials from each task. In Q1, the LPC was an undifferentiated, large amplitude, positive-going potential with a parietal-maximum topography. As RT increased, the LPC became increasingly differentiated so that by Q3 3 components in the latency range of P300 were visible: two constant-latency peaks, P286 (fronto-central), P341 (parietal); and one variable-latency deflection, P539 (parietal), whose peak latency lengthened as RT increased. An additional constant-latency peak, P198, was also recorded. Principal component analyses of the averaged wave forms confirmed the visual identification of these components. The fixed-latency peaks identified in the brain potentials of these subjects were similar in timing and topography to previously reported late positive components. This study demonstrated. however, that the LPC can be segregated into stimulus-related and response-related components.

Adolescent↗
PubMed1978

Immune reactivity during aging. I. T-helper dependent and independent antibody responses to different antigens, in vivo and in vitro.

The immunological status during aging was assessed by measuring the antibody response of the long-lived (C3H/eb X C57Bl/6J)F1 mice to various antigens in vivo and in vitro. In vivo, a decrease in antibody production to DNP and NIP haptenic determinants coupled on to BGG, as well as the response to SRBC, was observed. The decline was more pronounced in the IgG as compared to IgM antibodies. The results were recorded when various parameters such as antigen dose and kinetics of the response, were considered. Reduction of the antibody response was also noted when PVP was employed as immunogen. Similar results were noted when the responses to SRBC and DNP--polylysine were induced and followed in spleen organ cultures. In all of these experimental systems, the peak response was observed in mice 6--12 months old. From then on a gradual decrease was manifested, mice 30--36 months old producing significantly low responses. The results demonstrate that decrease in antibody production is expressed in the isolated spleen tissue in the same manner as in the intact animal. Furthermore, they were interpreted as indicating that the lesion may be at the T helper and the B cell compartments.

Aging↗
PubMed1978

Immune reactivity during aging. II. Analysis of the cellular mechanisms involved in the deficient antibody response in old mice.

Analysis was made of the cellular basis of decline in the antibody immune response with advancing age. Employing the cell transfer system, it was found that spleen cells of aged mice have a limited capacity to react to SRBC when transferred into young irradiated recipients. Partial reconstitution was achieved when thymus cells from young untreated donors were applied together with the spleen cells, suggesting that deficiency in T helper cell function is responsible in part for the limited response. Similar studies using the T helper-independent antigen PVP also resulted in low levels of antibodies in the irradiated recipients. Treatment of the spleen cells with anti-theta serum before transfer did not lead to an increased response. Hence, it is suggested that the reduced response is related to limited function in the B cell compartment, and not to function of T suppressor cells. Transfer of bone marrow cells from aged into young irradiated recipients indicated that cells capable of differentiation into antibody-producing cells are available during aging. It is thus maintained that the defect at the B cell level is of a developmental nature.

Aging↗
PubMed1977

A new technique for the treatment of guilt.

A behavioural technique is described suitable for the treatment of patients with high levels of guilt who attempt to relieve their depression by risk-taking activities which reflect their individual wishes and fears, or who suffer anxiety due to unacceptable past behaviour. It is recommended as an alternative brief method of treatment to psychoanalysis and is based on the application of behaviour therapy to a patient's psychopathology. Three case histories are described to illustrate the principles of the technique.

Adult↗
PubMed1975

Cortical evoked potentials elicited by real speech words and human sounds.

Averaged evoked potentials were recorded from PZ and left and right temporo-parietal electodes to real speech words and human sounds in 8 right-handed subjects. Stimuli were presented in a "no task" condition where the subject was instructed to listen attentively, and a vigilance condition where the subject responded to a particular word or sound during a run of such stimuli. The vigilance condition produced two classes of stimuli:signals and non-signals. Evoked potentials to physically identical words or sounds were examined when they were "no task", non-signal and signal stimuli. P300 amplitude increased significantly as a function of increasing task demands going from "no task" to non-signal to signal. When a strict statistical criterion for multiple comparisons (Bonferroni test) was applied in looking for asymmetries between hemispheres, only 2 isolated left greater than right differences turned out to be significant. Review of the literature concerning evoked potential correlates of differential hemispheric processing pointed up flaws in design, statistical technique, and inconsistencies in reported findings which suggested that while evoked potentials may sometimes reflect differences in hemispheric functioning, this effect is marginal at best.

Adult↗
PubMed1975

The late positive component (P300) and information processing in sentences.

Averaged visual evoked potentials to sequentially flashed words comprising a sentence were recorded from vertex and left and right temporoparietal electrodes in 8 right-handed subjects. In condition 1 the sentence took the form: The -eel is on the shoe, in which the first grapheme was omitted from the second word, so that the subject did not know the meaning of the second word until he viewed the last word. In condition 2, the sentence took the form: The heel is on the shoe, in which the second word was given and the last word provided no further information. P300 latency to words which delivered information (last word of condition 1, second word of condition 2) were significantly longer than P300 latency to any of the other words in the sentence, as well as to the same position word in the other condition. Comparisons of P300 latencies to redundant words (the, is, on) within and between conditions showed no significant differences. P300 amplitude to the last word was significantly larger than P300 amplitude to any of the other words within the sentence, even in condition 2 where the second word delivered information. The major effect of information delivery was on P300 latency, while "syntactic closure" had its major effect on P300 amplitude. The fact that evoked potentials to all words had P300 components was attributed to the engagement of the P300 system whenever task-related language stimuli are used.

Adolescent↗
PubMedDate not supplied

[2 cases of death caused by hepatic insufficiency after jejuno-ileal bypass for obesity].

Reference is made to 2 cases of fatal liver failure following jejuno-ileal by-pass for obesity, in which necropsy shown micronodular and the rarer fragmentary necrosis, in addition to serious steatosis. Liver alterations following by-pass are usually reversible and respond to the infusion of medicaments. The indication for surgical re-establishment of continuity, in which, if timely, leads to normalisation of liver shape and function, must be chosen without hesitation when changes, albeit reversible, appear to threaten life and resist treatment, and in all cases where biopsy points to progression towards irreversible sclerosis.

Adult↗
PubMedDate not supplied

Further studies of manually operated self-inflating resuscitation bags.

Four resuscitators were tested, of which three had recently been improved by the manufacturers (Danish-made Ambu, Air Bird, Laerdal Resusci 2), and one was new (Hope 2). All functioned well at extremes of temperature and all would deliver 100 percent O2 to the patient. All are essentially vice-free and represent great steps forward in resuscitator design.

Evaluation Studies as Topic↗