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Biomedical subjects

L E Walker

Publications and source records attributed to L E Walker.

At least 37 records · Page 2Linked to original sources
PubMed1989

Psychology and violence against women.

The discipline of psychology has made many contributions to the understanding of the social problem of men's violence against women during the past 15 years by reframing the problem as one of misuse of power by men who have been socialized into believing they are entitled to control the women in their lives, even by violent means. The new scientific psychology data base formed by integrating feminist gender analysis methods into more traditional psychological methodology is discussed, as are the implications of the resulting empirical data on which are based newer assessment, treatment, and forensic applications. A review of the major psychological advances in psychotherapy with women who have been sexual assaulted, exploited, and battered is presented, as well as implications for national policy. The feminist model presented is one in which science and practice concerns are carefully considered at all steps of the process. The article concludes with a discussion of the challenges involved in making the future training of psychologists more relevant to women's mental health concerns.

Female↗
PubMed1988

Primary structure and unique expression of the 22-kilodalton light chain of human neutrophil cytochrome b.

Cytochrome b comprising 91-kDa and 22-kDa subunits is a critical component of the membrane-bound oxidase of phagocytes that generates superoxide. This important microbicidal system is impaired in inherited disorders known as chronic granulomatous disease (CGD). Previously we determined the sequence of the larger subunit from the cDNA of the CGD gene, the X chromosome locus affected in "X-linked" CGD. To complete the primary structure of the cytochrome b and to assess expression of the smaller subunit, we isolated cDNA clones for the 22-kDa polypeptide by immunoscreening and confirmed their authenticity by direct N-terminal protein sequencing. Although the deduced amino acid sequence of the 22-kDa subunit is not overtly similar to other known cytochromes, we observed a 31-amino acid stretch of 39% identity with polypeptide I of mitochondrial cytochrome c oxidase centered on a potential heme-coordinating histidine. Similarities in the hydropathy profiles and spacing of histidines of the 22-kDa protein and myoglobin suggest structural motifs in common with other heme-containing proteins that are not readily revealed by primary amino acid sequences. Although RNA for the larger subunit has been found only in cells of the phagocytic lineage, stable RNA encoding the 22-kDa subunit was observed in all cell types. However, the stable 22-kDa protein was detected only in phagocytic cells that were expressing the larger subunit RNA. This observation suggests that the large subunit may play a role in regulating the assembly of the heterodimeric cytochrome b.

Amino Acid Sequence↗
PubMed1987

Antigenic mimicry of a human cellular polypeptide by Mycoplasma hyorhinis.

A 46-kilodalton (kDa) polypeptide was immunoprecipitated from radiolabeled extracts of human cell lines infected with Mycoplasma hyorhinis by murine monoclonal antibodies PF/2A and ML77. Both of these antibodies also reacted in an enzyme-linked immunosorbent assay (ELISA) with M. hyorhinis cells and with human and nonhuman cell lines infected with M. hyorhinis but failed to react with A7573 cells infected with any of 10 other species of the order Mycoplasmatales. PF/2A also reacted in the ELISA with certain human cell lines that were demonstrated to be free of mycoplasma infection. From extracts of these lines, a polypeptide antigen that appeared as a 24-kDa doublet on polyacrylamide gels was immunoprecipitated by PF/2A. When the PF/2A-reactive human cell lines were infected by M. hyorhinis, both the 46- and 24-kDa antigens were immunoprecipitated by PF/2A. ML77 did not react in the ELISA with any noninfected human cells tested and failed to immunoprecipitate a 24-kDa component from any human cells. In Western blotting analyses of extracts of M. hyorhinis cells, both PF/2A and ML77 stained a 46-kDa band. PF/2A also stained 24-kDa bands in Western blotting analyses of reactive human cells and M. hyorhinis cells, although a 24-kDa component was not precipitated from extracts of M. hyorhinis cells by PF/2A.

Antibodies, Monoclonal↗
PubMed1986

Labeling and comparative biodistribution of the monoclonal antibody KS1/4 in nude mice bearing human lung adenocarcinoma.

In order to evaluate some of the key factors that may allow the optimization of radiolabeled monoclonal antibodies for use as diagnostic and therapeutic tools to detect and treat human neoplasia, we compared the biodistribution of the anti-lung-tumor monoclonal antibody KS1/4, labeled with four different radionuclides, in athymic (nu/nu) mice bearing human lung adenocarcinoma. Several radiolabeling methods were used: the first involved coupling a suitable bifunctional chelating agent, such as DTPA, to the KS1/4 monoclonal antibody, followed by binding the radiometal, either 113mIn or 111In. Radioiodination was carried out by the chloramine-T method with 131I, and intrinsic labeling by generating the hybridoma in the presence of 75Se-methionine. An examination of tumors and major organs of mice injected with one of the above radiolabeled KS1/4 MoAbs, and biodistribution at various time intervals up to 96 h post injection revealed that iodination and intrinsic labeling yield the highest tumor uptake. Because of the relatively high deiodination that occurs in vivo, and the high 75Se content in the circulation, the preferential uptake (tumor-to-blood ratio) of these radiopharmaceuticals lags behind the equivalent ratios for the In-labeled MoAb. In the latter group of animals, a second consecutive injection of the labeled MoAb resulted in elevated blood level of radioindium, as well as a corresponding decrease in tumor-to-blood ratios.

Adenocarcinoma↗
PubMed1986

Ear oximetry to detect apnea and differentiate rapid eye movement (REM) and non-REM (NREM) sleep. Screening for the sleep apnea syndrome.

Ear oximetry is commonly employed in screening patients for the sleep apnea syndrome, but the lack of objective information regarding the duration of sleep, including the presence of rapid-eye-movement (REM) sleep, is a major limitation. Based on the premise that both apnea and sleep-state-dependent changes in ventilation give rise to distinctive patterns in the arterial oxygen saturation, we developed a systematic technique to analyze ear oximetric tracings for wakefulness, REM sleep, and non-REM (NREM) sleep. Fifty-four patients were studied by both all-night polysomnography and ear oximetry. A careful comparison of ear oximetric data for sleep states and apnea was then made, using polysomnography as the correct classification to determine sensitivity, specificity, predictive value positive, and predictive value negative of the ear oximetric tracings. When classification of sleep state was compared, ear oximetry correctly classified 280.5 (82 percent) of 340.9 hours of sleep that was either REM or NREM sleep. The sensitivity for classifying NREM sleep was 0.85, for REM sleep was 0.70, and for wakefulness was 0.49. The sensitivity by ear oximetry for apnea was 0.80, with a predictive value negative of 0.87. We conclude that although polysomnography must be performed for definitive evaluation, ear oximetry is a valuable screening test for sleep apnea because the presence or absence of apnea can be determined, total duration of sleep can be estimated, and NREM vs REM sleep can be differentiated.

Adult↗
PubMed1986

Antigens associated with human squamous cell lung carcinoma defined by murine monoclonal antibodies.

A panel of 12 monoclonal antibodies that preferentially react with human squamous lung carcinoma cells has been produced. All are reactive with fresh frozen sections of squamous cell lung carcinoma tissues in immunoperoxidase assays and are unreactive with lymphoblastoid cells, red blood cells, and fibroblasts in enzyme-linked immunosorbent assay. At least eight of these antibodies interact with cell surface components. These reagents can be subdivided into four groups based upon their reactivities. Groups 1 to 3 are unreactive with normal liver, lung, kidney, colon, spleen, and pancreas in immunoperoxidase assays. Group 1 antibodies (PF1/A, PF1/B, PF1/C, PF1/D, and PF1/E) are all of IgG3 subclass and immunoprecipitate nonsulfated glycoprotein components with molecular weights of 80,000 and 180,000 and a nonglycosylated polypeptide with a molecular weight of 38,000. Group 1 antibodies are also reactive with some lung adenocarcinomas and, with the exception of PF1/E, stain certain differentiated strata within normal adult plantar and fetal epidermis. Group 2 antibodies (PF2/A and PF2/B) react also with breast, gastric, and colonic adenocarcinomas and some tumors of neuroectodermal origin. Group 2 antibodies, which are both of IgG3 subclass immunoprecipitate a nonglycosylated Mr 24,000 polypeptide. Group 3 antibodies (PF3/A, an IgG1; PF3/B, an IgGM; and PF3/C, an IgG2a) react additionally with certain other tumors, as well as with normal adult and fetal epidermis. Group 4 antibodies (PF4/A, an IgG2a; and PF4/B, an IgG1) are less specific than those of the preceding groups, as they react with some normal tissues, including pancreatic islets and pneumocytes, as well as with a variety of adenocarcinomas and tumors of neuroectodermal origin. PF4/A and PF4/B immunoprecipitate Mr 100,000 and 95,000 glycoproteins, respectively.

Animals↗
PubMed1985

Human major histocompatibility complex class I antigens: residues 61-83 of the HLA-B7 heavy chain specify an alloreactive site.

A chemically synthesized peptide (sequence in text) homologous to residues 61-83 of the HLA-B7 heavy chain, induced antibodies that specifically recognized the HLA heavy chain-beta 2-microglobulin complex and the free heavy chain of the HLA-B7 antigen. These antibodies specifically immunoprecipitated the HLA-B7 beta 2-microglobulin complex solubilized from human lymphoblastoid cells by nonionic detergents and reacted with free HLA-B7 heavy chains in blots on nitrocellulose. These observations suggest that the antigenic conformation of this region of the HLA-B7 molecule is independent of the presence of beta 2-microglobulin and that amino acid residues 61-83 mimic an alloreactive site expressed by the HLA-B7 antigen.

Amino Acid Sequence↗
PubMed1985

Gender and victimization by intimates.

Recent data demonstrate that, although gender has an impact upon the experience of being a victim of an intimate's violence, there is no particular personality pattern that leads one to become a victim. Rather, women--who are socialized to adapt and submit, and who are likely to become victims of men's sexual violence or physical abuse--may not develop adequate self-protection skills as children, especially if they come from childhood homes in which females are victimized, leading to a later vulnerability to physical and sexual abuse. Men, however, socialized to express anger and aggression in an outward manner, learn to model the abuse witnessed or experienced in childhood and often learn that women are the "appropriate" recipients of this violence. Social learning theories of modeling and aggression are used to explain how such personality patterns develop, and the theory of learned helplessness is used to explain battered women's coping responses to their partners' abusive behavior. The extreme situation, in which a battered woman kills her partner in self-defense, is analyzed in order to understand women victims' sense of desperation and entrapment in severely abusive relationships and the extent to which their behaviors are in reaction to the abuse perpetrated by the mate.

Adult↗
PubMed1984

Biosynthetic studies of proteoglycans in human melanoma cells with a monoclonal antibody to a core glycoprotein of chondroitin sulfate proteoglycans.

Monoclonal antibody (Mab) 9.2.27 was utilized in a combination of biosynthetic and biochemical investigations as an immunological probe for the study of chondroitin sulfate proteoglycans (CSP) in human melanoma cells. Pulse-chase and long-term intrinsic labeling immunoprecipitation experiments combined with the biosynthetic inhibitors monensin, cycloheximide, and paranitrophenol-beta-D-xyloside all suggest that Mab 9.2.27 recognizes a set of glycoprotein molecules ranging to a 250-kDa glycoprotein which serves as the core glycoprotein for CSP in human melanoma cells. Peptide maps comparing the 250-kDa and CSP molecule verify that the 250-kDa glycoprotein is the CSP core protein in human melanoma cells. Further studies document that the CSP released by melanoma cells and recognized by Mab 9.2.27 contains (2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-beta-4-O-sulfo-D-galactose and 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-beta-6-O-sulfo-D-galactose saccharides and this CSP can interact with hyaluronic acid-Sepharose. Topographical studies indicate that this CSP has pericellular punctuated distribution on the melanoma cell surface and may play a role in cell-substrate interactions in the biology of metastatic human melanoma.

Aggrecans↗
PubMed1984

Antigens associated with a human lung adenocarcinoma defined by monoclonal antibodies.

Monoclonal antibodies KS1/4, KS1/9, and KS1/17 were developed in this laboratory from a fusion of the murine myeloma cell line P3X63Ag8 with spleens of BALB/c mice previously primed with UCLA P3 cells derived from a human adenocarcinoma of the lung. Monoclonal antibodies KS1/4 and KS1/17 seemed to recognize similar glycoprotein antigens on the lung carcinoma cells by indirect immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. However, mapping of [3H]lysine- and [3H]arginine-labeled tryptic peptides of antigens in specific immunoprecipitates of lung carcinoma cells by high-pressure liquid chromatography revealed a one peptide difference. Antibody KS1/9 did not immunoprecipitate any identifiable protein from detergent extracts of the immunizing cell line by routine methods and appears to detect a glycolipid antigen. Immunocytochemical analysis of tissue sections showed this monoclonal antibody to be reactive with adenocarcinomas of the lung and not with the other histological types of lung carcinoma or normal tissue. Monoclonal antibodies KS1/4 and KS1/17, however, reacted with 3 major histological types of lung cancer and minimally with the proximal tubules of normal kidney and the epithelium of bronchioles.

Adenocarcinoma↗
PubMed1983

N-terminal amino acid sequences of the alpha and beta chains of HLA-DR1 and HLA-DR2 antigens.

The N-terminal amino acid sequences of the alpha and beta chains of HLA-DR1 and HLA-DR2 antigens were obtained with subnanomole quantities of material by using a gas-liquid solid-phase sequencer. A comparison of the N-terminal amino acid sequences of HLA-DR1 and HLA-DR2 alpha chains revealed no differences. However, in the first 35 N-terminal residues of the beta chains from HLA-DR1 and HLA-DR2 antigens, two regions of variability are readily apparent, each comprising about six amino acids. Conceivably one or both of these variability regions may be responsible for the serologically defined polymorphism of HLA-DR alloantigens.

Amino Acid Sequence↗
PubMed1983

Anti-HLA antibodies of predetermined specificity: a chemically synthesized peptide induces antibodies specific for HLA-A,B heavy chain.

A chemically synthesized dodecapeptide (Asp-Ala-Ala-Ser-Pro-Arg-Glu-Glu-Pro-Arg-Ala-Pro), consisting of residues 39 through 50 of the HLA-B7 heavy chain sequence and containing a highly hydrophilic hexapeptide segment (Pro-Arg-Glu-Glu-Pro-Arg), induced antibodies that bound specifically to free HLA-A, and HLA-B heavy chains and to the soluble dodecapeptide. Although these antibodies reacted with free HLA-A,B heavy chains in blots on nitrocellulose, they failed to immunoprecipitate the HLA-A,B-beta 2-microglobulin antigen complex solubilized from human lymphoblastoid cells by nonionic detergents. These observations suggest that the physical characteristics of this particular soluble hydrophilic dodecapeptide may closely resemble nonallotypic determinants expressed by free HLA-A,B heavy chains and that such antigenic sites may be modified by conformational changes in the native HLA-A,B heavy chain-beta 2-microglobulin complex.

Amino Acid Sequence↗
PubMed1983

Generation of protein-reactive antibodies by short peptides is an event of high frequency: implications for the structural basis of immune recognition.

Recent studies have shown that chemically synthesized small peptides can induce antibodies that often react with intact proteins regardless of their position in the folded molecule. These findings are difficult to explain in view of the experimental and theoretical data which suggest that in the absence of forces provided by the folded protein, small peptides in aqueous solution do not readily adopt stable structures. In order to rationalize the two findings, there has been general acceptance of a stochastic model which suggests that the multiple conformers of a peptide in solution induce sets of antibodies with a small percentage reactive with conformations shared by the folded protein. This stochastic model has become less tenable as the success rate for the generation of protein-reactive anti-peptide antibodies has grown. To test the stochastic model, we have used monoclonal anti-peptide antibodies as a way of estimating the frequency with which small peptides induce antibodies that react with folded proteins. We have made monoclonal antibodies to six chemically synthesized peptides from three proteins. The frequency with which the peptides induce protein-reactive antibodies is at least 4 orders of magnitude greater than expected from previous experimental work and vastly different from what would be predicted by calculating the possible number of peptide conformers in solution. These findings make the stochastic model less likely and lead to consideration of other models. Aside from their practical significance for generation of highly specific reagents, these findings may have important implications for the protein folding problem.

Amino Acid Sequence↗
PubMed1983

Cessation of thermoregulation during REM sleep in the pocket mouse.

Electrophysiological sleep patterns, respiration frequency, brain temperature (Tbr), and ear temperature (Tear) were recorded from five pocket mice (Perognathus longimembris) exposed to ambient temperatures (Ta) of 22.5, 27.5, 32.5, and 35.0 degrees C. Thermoregulation was curtailed during rapid-eye-movement (REM) sleep, since Tbr declined following REM onsets at Ta's below thermoneutrality and increased at Ta's above thermoneutrality. Tbr subsequently returned to pre-REM levels following the termination of each REM episode. Respiratory frequency was inversely related to Ta but not as strongly during REM sleep as during slow-wave sleep (SWS). These results confirm previous reports of loss of thermoregulatory ability during REM sleep. Mean duration and proportions of wakefulness, SWS, and REM sleep were unaffected by Ta, consistent with earlier findings on ground squirrels, but differing from reports of decreased REM sleep in nonhibernators. Hibernators may have lower peripheral thermosensitivities than nonhibernators, facilitating sleep at low ambient temperatures and during entrance into hibernation.

Animals↗
PubMed1982

A high yield purification procedure for alpha and beta chains of HLA-DR antigens.

A procedure is described for purifying to homogeneity the alpha and beta chains of HLA-DR antigen from the homozygous human lymphoid cell line LG-2. The procedure involves a combination of lectin affinity as well as classical and high pressure liquid chromatography. From 100 g of packed cells, 8 mg (235 nmol) of alpha chain and 7 mg (205 nmol) of beta chain were isolated.

Amino Acid Sequence↗