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Biomedical subjects

D Kaplan

Publications and source records attributed to D Kaplan.

At least 145 records · Page 8Linked to original sources
PubMed1986

The effectiveness of anti-Ia-immunotoxins in the suppression of MLR.

The potential use of a mouse anti-Ia monoclonal antibody conjugated with a plant toxin as an immunosuppressive agent for organ transplantation was examined by studying the mixed lymphocyte reaction (MLR). In initial observations in a murine system utilizing strains A/J and C57B1/6 (B6), it was shown that a rich-toxin-conjugated anti-I-Ek monoclonal antibody (13.4-immunotoxin) would kill Ia-bearing cells of strain A/J (I-Ek)--but not of strain B6, the cells of which lack I-E determinants. Studies reported here demonstrated that 13.4-immunotoxin effectively removed stimulatory cells from the I-E-bearing spleen cells but had no effect on spleen cells lacking I-E determinants or responder lymph node cells (I-E+ or I-E-) similarly treated (i.e., 1 microgram/10(6) cells). Taking advantage of the finding that such anti-I-E antibodies react with rat spleen cells bearing class II major histocompatibility complex molecules, we utilized these toxin-conjugated antibodies to inhibit MLR in rats. Assuming that the MLR is an in vitro representative of graft rejection, we suggest that such immunotoxins might be useful for pretreatment of organ allografts for transplantation across major histocompatibility barriers.

Animals↗
PubMed1986

The Azolla-Anabaena azollae Relationship : XII. Nitrogenase Activity and Phycobiliproteins of the Endophyte as a Function of Leaf Age and Cell Type.

Nitrogenase activity was measured in leaves along the main stem axes of Azolla pinnata R. Br. The activity was negligible in leaves of the apical region, rapidly increased to a maximum as leaves matured, and declined in aging leaves. In situ absorption and fluorescence emission spectra were obtained for individual vegetative cells and heterocysts in filaments of the A. pinnata and Azolla caroliniana endophytes removed from the cavities of progressively older leaves. These spectra unequivocally demonstrate the occurrence of phycobiliproteins in the two cell types of both endophytes at the onset of heterocyst differentiation in filaments from young leaves, during the period of maximal nitrogenase activity in filaments from mature leaves, and in filaments from leaves entering senescence. Phycobiliproteins of the A. caroliniana endophyte were purified and extinction coefficients determined for the phycoerythrocyanin, phycocyanin, and allophycocyanin. The phycobiliprotein content and complement of sequential leaf segments from main stem axes and of vegetative cell and heterocyst preparations were measured in crude extracts. There was no obvious alteration of the phycobiliprotein complement associated with increasing heterocyst frequency of the endophyte in sequential leaf segments and the phycobiliprotein complement of heterocysts was not appreciably different from that of vegetative cells. These findings indicate that the phycobiliprotein complement of the vegetative cell precursor is retained in the heterocysts of the endophyte.

Journal Article↗
PubMed1986

Phosphoinositide kinase activity and transformation.

We have used the DNA tumor virus polyoma as a model system to examine whether the phosphatidylinositol (PI) turnover pathway is a critical target for transforming gene products. Polyoma-infected cells show elevated levels of polyphosphoinositides and polyphosphoinositols, and a PI kinase activity is associated with middle T antigen, a transforming gene product of polyoma virus. In anti-T immunoprecipitates from polyoma-infected or -transformed cells, comparisons of wild-type and polyoma mutants defective for transformation show a strong correlation between middle T-associated PI kinase activity and transforming ability. Middle T has previously been found to associate at the plasma membrane with pp60 c-src and to activate it as a tyrosine kinase. c-src itself does not appear to phosphorylate PI; however, the middle T/pp60 c-src tyrosine kinase activity may be important for activation of PI kinase. Ammonium orthovanadate, a tyrosine phosphatase inhibitor, elevates the middle T/pp60 c-src-associated PI kinase activity. We propose that middle T/pp60 c-src activates a PI kinase and modulates PI turnover in vivo by tyrosine phosphorylation.

1-Phosphatidylinositol 4-Kinase↗
PubMed1986

Fetal wastage in patients with rheumatoid arthritis.

Ninety-six women with rheumatoid arthritis (RA) were found to have an abortion ratio higher than that of a comparison group (p = 0.005). This was true even before the onset of their RA (p = 0.007). The fertility rate of the patients with RA was not different from the control patients. This suggests the presence of a "rheumatoid diathesis" which long antedates the expression of the disease.

Abortion, Spontaneous↗
PubMed1986

The age of death of the parents of patients with rheumatoid arthritis: a preliminary study.

The hypothesis was tested that the shortened life expectancy of patients with rheumatoid arthritis (RA) is, partially at least, due to a familial factor which independently shortens life expectancy, whether the person has RA or not. We therefore compared the ages of death of the parents of patients with RA with the ages of the death of the parents of a control group. The parents of the patients with RA had a mean age of death of 64.76; 18.23 years versus 68.29; 18.24 years for the parents of the control group (p = 0.006). This finding is compatible with the hypothesis: whether genetic or environmental factors are involved is unknown.

Adult↗
PubMed1985

Expression of polyoma early gene products in E. coli.

The three products of the early region of polyoma virus have been cloned for expression in E. coli using the Tac promoter. Although the identical promoter and ribosome binding site are used in each final construction, the observed level of protein expression is different for each protein. While plasmids expressing wild type T antigens as well as a plasmid expressing the truncated Py-1387T middle T antigen lacking the membrane-anchoring sequence give rise to synthesis of proteins readily detectible by 35S-methionine labeling and immunoprecipitation, only small T and the middle T of Py-1387T are made in amounts sufficient for ready detection in total cell protein. Unlike middle T expressed in animal cells, middle T produced in E. coli is not detectibly phosphorylated. Further, the E. coli protein lacks tyrosine kinase activity.

Antigens, Viral, Tumor↗
PubMed1985

Comparative angiographic right and left ventricular volumes.

Comparative angiographic right and left ventricular volumes and right and left ventricular ejection fractions have been reported in the same normal infants and children. This relationship was assessed in adult patients to determine if these pediatric observations persist in later life. Seventeen adults, who had both right and left ventricular angiograms and who had no demonstrable organic heart disease, were studied. Right ventricular end-diastolic volume ranged from 54 to 98 (76 +/- 14, mean +/- SD) cc/m2 and left ventricular end-diastolic volume ranged from 48 to 90 (70 +/- 12) cc/m2; p less than 0.03. Right ventricular end-systolic volume ranged from 22 to 47 (33 +/- 8.0) cc/m2 and left ventricular end-systolic volume ranged from 13 to 34 (22 +/- 5.3) cc/m2; p less than 0.00005. Calculated right ventricular stroke volume ranged from 31 to 60 (43 +/- 8.3) cc/m2 and left ventricular stroke volume ranged from 29 to 70 (48 +/- 11) cc/m2; p = NS. Calculated right ventricular ejection fraction ranged from 0.48 to 0.62 (0.57 +/- 0.04) and the left ventricular ejection fraction ranged from 0.57 to 0.84 (0.68 +/- 0.07; p less than 0.00005. Both right ventricular end-systolic and end-diastolic volumes were greater than left ventricular end-systolic and end-diastolic volumes. This resulted in decreased right ventricular ejection fraction compared to left ventricular ejection fraction. The difference between the two ventricles may be due to compliance, muscle mass, and anatomic configuration with a net result of one chamber more completely emptying than the other. Thus it appears that the relationships between right and left ventricular volumes noted in infancy and childhood persist in adult life.

Adolescent↗
PubMed1985

Spine problems in emergency department patients: does every patient need an x-ray?

Two hundred adults with spine problems were evaluated by one examiner in a community hospital emergency department. A patient was considered to have a spine problem requiring evaluation if presenting with pain in the neck or back not obviously caused by a process outside of the spine (eg, back pain in a patient with renal colic); if there was known or suspected trauma to the neck or back; or if the clinical setting suggested spinal tumor, infection, metabolic bone disease, or ankylosing spondylitis. Of the 200 patients, 143 were studied by x-ray films. Six patients (6 of 143, or 4%) had x-ray abnormalities that mandated specific treatment. Fifty-two of the 57 patients not receiving x-ray studies were followed up at 2 months. Thirty-three of these patients (63%) had no x-ray studies in the interim and had improved greatly. Nineteen (37%) had been studied radiographically in the interim, but no abnormality requiring specific treatment was found in any patient. Emergency physicians should be aware that x-ray studies of the spine have low utility for patients whose histories and examinations are benign, that especially for women lumbosacral x-ray studies involve high gonadal radiation exposure, and that selected patients can be managed without x-ray studies and still be satisfied recipients of adequate medical care.

Adolescent↗
PubMed1985

The effectiveness of anti-Ia-immunotoxins in the suppression of MLR.

The potential use of a mouse anti-Ia monoclonal antibody conjugated with a plant toxin as an immunosuppressive agent for organ transplantation was examined by studying the mixed lymphocyte reaction (MLR). In initial observations in a murine system utilizing strains A/J and C57B1/6 (B6), it was shown that a rich-toxin-conjugated anti-I-Ek monoclonal antibody (13.4-immunotoxin) would kill Ia-bearing cells of strain A/J (I-Ek)--but not of strain B6, the cells of which lack I-E determinants. Studies reported here demonstrated that 13.4-immunotoxin effectively removed stimulatory cells from the I-E-bearing spleen cells but had no effect on spleen cells lacking I-E determinants or responder lymph node cells (I-E+ or I-E-) similarly treated (i.e., 1 micrograms/10(6) cells). Taking advantage of the finding that such anti-I-E antibodies react with rat spleen cells bearing class II major histocompatibility complex molecules, we utilized these toxin-conjugated antibodies to inhibit MLR in rats. Assuming that the MLR is an in vitro representative of graft rejection, we suggest that such immunotoxins might be useful for pretreatment of organ allografts for transplantation across major histocompatibility barriers.

Animals↗
PubMed1984

Evaluation of the first 70 patients in the center for male sexual dysfunction of Beth Israel Medical Center.

We evaluated 70 patients for male sexual dysfunction in our center during its first 6 months of operation. The results of the analysis demonstrated that 55 per cent had organic impairment. Several important findings should be emphasized. There was mild elevation of serum prolactin in 6 cases, none of which was the direct cause of the impotence. A total of 15 patients had a diagnosis of either impaired glucose tolerance or overt diabetes (7 with organic and 8 with psychogenic disease). Therefore, the diagnosis of diabetes or impaired glucose tolerance, whether known previously or not, should not be accepted as confirming the organicity of impotence. Also, nocturnal penile tumescence alone confirmed the diagnosis of psychogenic impotence only when a rigid erection 5 minutes in duration occurred. The absence of nocturnal erections cannot be interpreted as conclusive evidence of organic impotence. Finally, a definitive diagnosis of psychogenic impotence was made based only on visual sexual stimulation in 6 patients. Our results emphasize further that etiologic factors of organic or psychogenic impotence are complex and that a multidisciplinary approach should be used.

Blood Pressure↗
PubMed1984

The onset of disease in twins and siblings with systemic lupus erythematosus.

We reviewed both the published cases of systemic lupus erythematosus (SLE) occurring in siblings as well as our own, in regard to the ages of onset and the calendar year of onset in the sibling pairs. These data were compared with the same data in non-consanguineous, noncohabiting matched control pairs of patients with SLE. Compared to the control patients, we found no tendency for cases in siblings to occur at the same age, but a significant tendency to occur close together in time, thereby implicating an environmental agent as either a causal or triggering factor leading to expression of the disease.

Adolescent↗
PubMed1983

The effectiveness of a preoperation preparation program in reducing anxiety in children.

A study to assess the effectiveness of a preoperative preparation program on the child and family was undertaken. Three groups of mothers and children who were to undergo tonsillo-adenoidectomy were tested, pre- and postoperatively, using a questionnaire and IPAT Anxiety Scale. Differences were noted in the socioeconomic and educational backgrounds of the mothers who came of their own accord, those who were telephoned and those who did not attend the preoperative program. These differences affected the parents' expectations of the program and their explanations to the children. Children's, but not mothers', anxiety appeared to reduced by attendance at the program. The IPAT Anxiety Scale revealed that the anxiety of mothers of children who did not attend the preoperative preparation program was the highest of all three groups.

Anxiety↗
PubMed1983

A survey of osteoarthritis of the knee in the elderly.

We evaluated the signs and symptoms suggestive of osteoarthritis (OA) of the knee in 682 elderly people. The results suggest that both the frequency of signs and symptoms and the degree of severity remain constant in the 7th, 8th and 9th decades. Differences between men and women and between blacks and whites were also noted--women and blacks tending to have more frequent and more severe evidence of OA of the knee. These data suggest that OA of the knee is a specific disease that affects only a portion of the population and is not inevitably progressive.

Aged↗
PubMed1982

Studies of the conformation of bilirubin and its dimethyl ester in dimethyl sulphoxide solutions by nuclear magnetic resonance.

The conformation of bilirubin and its dimethyl ester in dimethyl sulphoxide (DMSO) was investigated by n.m.r. spectroscopy. The chemical shifts of the pyrrole NH and Lactam protons of bilirubin and its dimethyl ester in DMSO indicate a strong interaction with the solvent. Inter-proton distances were calculated from nuclear Overhauser effects (NOE), selective and non-selective relaxation times (T1) and rotational correlation times taken from 13C relaxation times. The interproton distances indicate that the conformation of the skeleton of bilirubin and its dimethyl ester in DMSO is similar to that of bilirubin and mesobilirubin in the crystalline state and in chloroform solutions, except for a possible slight twist of the pyrrolenone rings about the methine bonds, which may be a consequence of solvation of the NH groups by DMSO. Unlike in chloroform solutions, no direct hydrogen-bonding occurs between the carboxylic acid and the lactam groups of bilirubin in DMSO, as shown by the absence of an NOE between these groups. The fast exchange of the pyrrole NH protons with 2H shows that no hydrogen-bonding occurs between these protons and the propionic residues, in line with their solvation by DMSO. From the above results, and from the slowness of the internal motion of the propionic residues of bilirubin and its dimethyl ester, it is concluded that these residues are tied to the skeleton via bound solvent molecules.

Bilirubin↗