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Biomedical subjects

D Cohen

Publications and source records attributed to D Cohen.

At least 631 records · Page 35Linked to original sources
PubMed1984

Complications of the Angelchik antireflux prosthesis.

Various complications have been reported recently for the Angelchik antireflux prosthesis, a silicone-gel prosthesis used in the treatment of gastroesophageal reflux and associated hiatal hernia. We have studied the cases of 11 patients with complications of this prosthesis and have reviewed the literature for others. Complications included 8 erosions of the device into the gastrointestinal tract, 1 migration, 1 improper placement, and 1 case believed to be surgical trauma. These complications represent those typical to reflux surgery and some unique to the Angelchik prosthesis (migration and erosion). The exact frequency is unknown, with the manufacturer estimating migration at 0.81% and erosion at 0.15%. Available data indicate that complications may occur up to several years after implantation, and physicians may not recognize the problems with the prosthesis if they are unaware of the complications.

Adult↗
PubMed1984

Lack of beta 2-microglobulin on the surface of canine transmissible venereal tumor cells.

beta 2-Microglobulin (beta 2m) expression on the cell surface of the naturally occurring, allotransplantable canine transmissible venereal tumor (TVT) was investigated by use of indirect membrane immunofluorescence and radioimmunoassay. Two cell populations were identified in animal-derived, collagenase-disaggregated TVT cell suspensions. About 80% of the cells lacked surface beta 2m expression, whereas about 20% of the cells strongly reacted with anti-dog beta 2m serum. With the use of a cell separation technique, beta 2m-negative cells were demonstrated to carry TVT markers on their surface, whereas the beta 2m-positive cells did not express the tumor markers. The beta 2m-positive cells seemed, therefore, to be tumor-infiltrating host cells. These findings were supported by fluorescence staining studies of frozen sections of the TVT. The lack of beta 2m expression on the surface of TVT cells might explain the allotransplantability of this neoplasm, since beta 2m expression on the cell surface appeared to be obligatory for the expression of class I major histocompatibility complex antigens.

Animals↗
PubMed1984

Sialic acid on the surface of photoreceptors and pigment epithelium in RCS rats.

Incubation of isolated retinas and pigment epithelium (PE) from normal and dystrophic RCS rats with colloidal iron (CI) at pH 1.8 resulted in dense labeling of rod outer segments (ROS) and PE surfaces. Pretreatment with neuraminidase reduced subsequent binding of CI. The authors conclude, therefore, that sialic acid residues are localized on the ROS and PE surfaces. In dystrophic rats, uningested ROS tips, which accumulate in the subretinal space, did not bind CI.

Animals↗
PubMed1984

Leave-takings and reunions of infants, toddlers, preschoolers, and their parents.

The leave-taking and reunion behaviors of infants, toddlers, preschoolers, and their parents were observed as the children were "dropped off" and "picked up" at their nursery school each day. On arrival at their classroom, infants and toddlers related primarily to their parents, whereas preschoolers related to their teachers. Girls more frequently engaged in interaction with their teachers, and boys more frequently approached the children's play activities. Distress behaviors during the parents' departures were most frequently shown by toddlers, and the toddlers' parents hovered about them and " sneaked out of the room" more frequently. Children dropped off by mothers versus fathers showed more attention-getting behavior and crying, and mothers versus fathers engaged in more "distracting-the-child" behaviors and showed a longer latency to leave the classroom. During the second semester of observations parents and children spent less time relating to each other during leave-taking, children protested the departures less frequently, and the parents left the classroom more quickly. Regression analyses on distress behaviors during leave- takings and ambivalent behavior during reunions suggested that parent behaviors such as verbal explanation, distracting the child, latency to leave, and " sneaking out of the room" were correlated with children's distress and leave-taking distress was related to ambivalent behavior at reunion.

Attitude↗
PubMed1984

Treatment of canine transmissible venereal tumor by intravenous administration of protein A.

To determine if protein A can induce tumoricidal effects, transmissible venereal tumor-bearing dogs were treated by intravenous protein A administration. Each dog in the experimental group was treated twice a week with protein A, 100 micrograms/kg body weight, for a total of 10 treatments. Control dogs were treated with a 0.9% sodium chloride solution. No decrease in tumor volume attributable to protein A treatment was observed. However, transient healing of ulcerated tumors was observed in two dogs in the protein A-treated group but not in any in the control group. Following the first inoculation of protein A, a significant transient increase in polymorphonuclear cells and a significant transient decrease in lymphocyte and monocyte counts was detected, with a return of the counts to pretreatment levels by 24 h after the last protein A treatment. Intravenous protein A administration also failed to induce tumor regression in a guinea pig and a murine tumor model. These results suggest that the antitumor effects observed in protein A immunoadsorption studies have not been induced by leakage of protein A into the circulation.

Animals↗
PubMed1983

Interleukin 2 induces antigen-reactive T cell lines to secrete BCGF-I.

Antigen-activated T lymphocytes produce within 24 h of stimulation a factor that is indistinguishable biochemically and functionally from the B cell co-stimulating growth factor, BCGF-I, originally identified in induced EL4 supernatants: Supernatants from antigen-stimulated T cell lines are not directly mitogenic for resting B cells, but synergize in an H-2-unrestricted manner with anti-Ig activated B cells to produce polyclonal proliferation but not antibody-forming-cell development; biochemical studies reveal the B cell co-stimulating factor present in antigen-stimulated T cell line supernatants is identical by phenyl Sepharose chromatography and isoelectric focusing (IEF) to EL4 supernatant BCGF-I. We thus conclude that normal T cells produce BCGF-I in response to antigenic stimulation. Analysis of the mechanism of BCGF-I production by antigen-stimulated T cells showed that optimum amounts of BCGF-I were obtained as quickly as 24 h post-stimulation, and that the factor producing cells in the T cell line investigated bore the Lyt-1+2- phenotype. As few as 10(4) T cells produced sufficient BCGF-I to support the proliferation of 5 X 10(4) purified anti-Ig activated B cells. Finally, the activation of normal T cell lines to produce BCGF-I required either antigen presented in the context of syngeneic antigen-presenting cells (APC) or interleukin 2 (IL-2).

Animals↗
PubMed1983

Imipramine and brief therapists-aided exposure in agoraphobics having self-exposure homework.

Forty-five chronic agoraphobics were randomly assigned to treatment by placebo or imipramine in doses up to 200 mg/day for 28 weeks. All patients also had systematic self-exposure homework with an instruction manual. In addition, half of each drug group had therapist-aided exposure and half had therapist-aided relaxation, each totalling three hours. Patients in both drug groups improved substantially and maintained their gains for one year of follow-up. Imipramine had no significant therapeutic effect despite satisfactory plasma levels and significant drug side effects. Patients' low initial Hamilton depression scores might explain the absence of any drug effect. Antidepressants may be ineffective for agoraphobics who have normal mood. Brief therapist-aided exposure improved phobias and panics to a significant but limited extent, and is a useful adjuvant to self-exposure homework, which can be a powerful therapeutic agency by itself.

Adult↗
PubMed1983

Toxicological evaluation of a liquid fraction derived from palm oil.

The possible toxicity and mutagenicity of a heated liquid fraction derived from palm oil by transesterification was tested with rats fed diets containing 15% of the oil and by various in vitro and chemical assays on the animals sera. No adverse effects of any kind were noted in the animals fed diets containing a high level of the oils, and the Ames Test failed to reveal a mutagenic potential in any of them. The chemical tests did not show any noteworthy undesirable changes, either.

Acetylcholinesterase↗
PubMed1983

Characterization of amyloid deposits and P component from a patient with factor X deficiency reveals proteins derived from a lambda VI light chain.

Amyloid fibrils were isolated from a spleen obtained at surgery from a 58-year-old white man with primary amyloidosis presenting with factor X deficiency and responding dramatically to splenectomy. Gel filtration on Ultragel ACA 54 in 5 M guanidine 1 M acetic acid yielded components with molecular weights between 17,000 and 13,000. Two of them (17K and 15K) were studied in detail. Antigenic and amino acid sequence analysis showed that these proteins were related to lambda VI immunoglobulin light chain. The predominant protein subunits of the amyloid fibril of the deposits (17K) was processed at the carboxy terminus in the same section of the constant region as the only other lambda VI amyloid protein previously reported. Amino terminal sequence of the 15K protein revealed not only degradation at the C terminal, but also minor degradation at the amino terminal (three residues difference from the 17K species). P component was also isolated from the spleen and characterized. This represents the first antigenic and sequence analysis of tissue amyloid proteins and P component from a patient presenting with factor X deficiency and another example of amyloid proteins derived from the newly discovered amyloidogenic lambda VI light chain subgroup.

Amino Acids↗
PubMed1983

Surgical treatment of anorectal melanomas.

Thirty cases of anorectal melanoma have been recorded in Israel from 1960 to 1981. The frequency of the disease doubled in the last decade (from 10 to 20 cases). A clear predominance has been noted among Jews of European descent (18 patients) as opposed to Sephardic Jews (9 patients) or Arabs (3 patients). From this series, the emerging conclusion is that in most cases radical surgery (abdominoperineal resection) is seldom indicated. It is doubtful whether this form of treatment increases the survival while affecting considerably the quality of life. Survival correlated well with the stage of disease at the time of diagnosis. No such correlation could be established with the type of treatment employed.

Adult↗
PubMed1983

Demonstration of useful differences between magnetoencephalogram and electroencephalogram.

For a dipole source, theory predicts 3 useful differences between the MEG and EEG spatial patterns over the head. These are seen when a comparison is made between theoretical MEG and EEG maps, due to the dipole in a spherical model of the head. If true, these differences would allow the MEG to better localize or differentiate neural sources in some ways than does the EEG. A first experimental test of the differences is made here. A comparison is made between MEG and EEG maps due to a neural source which appears to behave as a dipole (N20 of the somatic evoked response). The same 3 differences are seen, therefore the predicted differences are confirmed experimentally. The first 2 differences, due only to the tangential component of the dipole, are that the MEG pattern is rotated by 90 degrees from the EEG pattern and is one-third tighter. The first allows the MEG to localize a tangential dipole better in a preferred direction, across the dipole (while the EEG does so along the dipole); the second allows the MEG to localize somewhat better in its preferred direction than the EEG does in its preferred direction. The third difference is due only to the radial component of the dipole; while the MEG receives no contribution from this component, the EEG pattern is asymmetrical and is heavily weighted by it. This allows the MEG to reveal tangential sources which are obscured by the radial sources in the EEG. For sources which cannot be approximated by a dipole, the MEG-EEG differences will depend on the particular case; however, the spherical model can now be used with more confidence to predict differences in these cases.

Brain↗
PubMed1983

Cytochemical evaluation of anionic sites on the surface of cultured pigment epithelium cells from normal and dystrophic RCS rats.

Anionic sites on the surface of cultured pigment epithelium cells from normal and dystrophic rats were studied. Cytochemical procedures and quantitative analysis were employed in order to determine distribution patterns and labeling densities. Anionic sites, in general, were localized with cationized ferritin at pH 7.0. The presence and density of sialic acid residues on the pigment epithelium cell surface were evaluated with colloidal iron at pH 1.8. Dystrophic cells contained 20% more cationized ferritin-binding sites as compared with normal pigment epithelium cells. With colloidal iron, an 18% increase in labeling density was measured in dystrophic pigment epithelium cells. Pretreatment with neuraminidase reduced subsequent labeling with colloidal iron by 93-97%. Thus, the presence of sialic acid residues on the surface of pigment epithelium cells and a significant increase in its content on the surface of dystrophic cells were established.

Animals↗
PubMed1983

Genetic mapping of a human class II antigen beta-chain cDNA clone to the SB region of the HLA complex.

A class II antigen beta-chain cDNA clone was isolated from a human B-cell cDNA library by using as a probe the murine I-A beta gene. This cDNA clone, pHA beta, was shown to be distinct from the DC beta- and DR beta-related loci by DNA sequence analysis, thus suggesting that it might correspond to a third polymorphic human class II locus, SB, which encodes secondary B-cell antigens. Genetic mapping of this beta-chain cDNA clone to the SB region was performed by the blot hybridization procedure. We showed that (i) within panels of HLA-DR homozygous human B-cell lines and of unrelated individuals who have been typed for HLA antigens, differential mobility of DNA fragments segregated with distinct SB genotypes; (ii) gamma-ray-induced deletion mutants that have lost the expression of DR or DC/MT antigens but maintain SB expression preserved a pattern consistent with (a) their SB phenotype and (b) the genetic independence of the SB locus with respect to DR and DC/MT; and (iii) within an informative family, two siblings differing only for one allele at the SB locus (because of the occurrence of an internal recombination between DR and GLO) and otherwise HLA identical exhibited a restriction enzyme polymorphism linked to the SB locus. Therefore, all available data are compatible with identity between HA beta and SB beta.

Alleles↗
PubMed1983

Analysis of HLA class I genes with restriction endonuclease fragments: implications for polymorphism of the human major histocompatibility complex.

Cellular DNA from HLA-typed individuals was digested with the restriction endonucleases HindIII, EcoRV, and EcoRI. The separated restriction endonuclease fragments were hybridized with a HLA class I cDNA probe by using the Southern transfer technique. Digestion of cellular DNA with HindIII generated 22 restriction endonuclease fragments, 11 of which showed polymorphism for presence or absence in a population sample. With EcoRV, 13 fragments were identified; 6 showed polymorphism. EcoRI generated 11 fragments, of which 1 was polymorphic. Of these 18 polymorphic fragments generated by the three restriction endonucleases, each of 5 was found to be positively associated with one allele of the HLA-A or -B allelic series (HLA-Aw24, -B8, -B15, -Bw35, and -B40). One fragment was positively associated with two HLA-A series alleles (HLA-A1 and -A11). Another fragment was positively associated with five HLA-B series alleles (HLA-B5, -B7, -B14, -Bw16, and -Bw35) and one fragment was positively associated with alleles at two loci (HLA-B14 and -Cw5). The serologically defined allele HLA-Aw24 was associated with two polymorphic fragments, one association showing a positive correlation and the other a negative correlation. Each informative family studied thus far has shown segregation of the restriction fragment with the associated serologically defined allele. The fragments associated with serologically defined alleles occurred in the population sample studied at low or moderate frequencies. The remaining polymorphic fragments occur at high frequency, suggesting that class I genes not serologically detected show less polymorphism than serologically defined class I genes.

Alleles↗
PubMed1983

Polymorphic restriction endonuclease fragment segregates and correlates with the gene for HLA-B8.

Cellular DNA from HLA-typed individuals was digested with the restriction endonuclease EcoRV. After electrophoresis and transfer to a hybridization membrane, the restriction endonuclease fragments were probed with cDNA carrying the nucleotide sequence encoding a class 1 HLA gene. Polymorphism for presence or absence of various EcoRV fragments was noted in a panel of unrelated HLA-typed individuals. A polymorphic 8.6-kilobase pair EcoRV fragment was found which correlated in the panel with the serologically defined gene HLA-B8. A family study revealed that this fragment segregated with the haplotype carrying the HLA-B8 gene. This fragment may carry the gene for HLA-B8 or it may represent another class 1 gene (or pseudogene) in linkage disequilibrium with HLA-B8.

DNA Restriction Enzymes↗
PubMed1983

Sleep disturbances in the institutionalized aged.

One hundred eighty nursing home residents, not psychotic or demented, average age 82 years, were administered a 30-minute structured interview to identify and characterize their sleeping patterns, health status, medications, psychosocial environment, and living conditions. In addition, both the residents and the night nurses rated quality of sleep on a five-point scale. Residents and nurses on all shifts also rated appetite and exercise on five-point scales. Residents were classified as having a sleep disturbance if they met at least one of the following criteria and reported poor sleep quality: onset of sleep latency greater than 30 minutes, three or more nighttime awakenings, and less than six hours sleep per night. Forty-five per cent of the residents met at least one clinical research criterion. Residents with sleep disturbance rated their sleep quality significantly lower than their peers not meeting research criteria. However, the nurses' ratings did not discriminate problem sleepers, and they correlated poorly with the residents' ratings. These subjective patient evaluations are discussed in relation to nursing evaluations, prescription of hypnotic medications, and other variables.

Aged↗
PubMed1983

The desk directory of social resources: a physicians' reference guide to social and community services for the aged.

Physicians not only have a responsibility for the diagnosis and management of illness in the aged but also must address the patient's emotional needs, functional status, and psychosocial problems. The Institute of Medicine Report on Geriatric Medical Education has emphasized the need to train physicians to understand how the social components of care enhance the course and outcome of treatment. A physician's reference guide to social and community services should be developed to provide information that will enable clinicians to integrate medical and community health services into their practice.

Aged↗