Association of Oral Health with Frailty, Malnutrition Risk and Functional Decline in Hospitalized Older Adults: A Cross-Sectional Study

BACKGROUND

Poor oral health is known to be associated with adverse outcomes, but the frequency and impact of poor oral health on older adults in the acute inpatient setting has been less well studied.

OBJECTIVES

We examined the association between oral health, frailty, nutrition and functional decline in hospitalized older adults.

DESIGN

Retrospective cross-sectional study.

SETTING AND PARTICIPANTS

We included data from 465 inpatients (mean age 79.2±8.3 years) admitted acutely to a tertiary hospital.

METHODS

We evaluated oral health using the Revised Oral Assessment Guide (ROAG), frailty using the Clinical Frailty Scale (CFS), malnutrition risk using the Nutritional Screening Tool (NST) and functional status using a modified Katz Activities of Daily Living (ADL) scale. We examined cross-sectional associations of oral health with frailty, malnutrition risk and functional decline on admission, followed by multivariate logistic regression models evaluating the association between poor oral health and the aforementioned outcomes.

RESULTS

343 (73.8%), 100 (21.5%) and 22 (4.7%) were classified as low, moderate and high risk on the ROAG, respectively. Poorer oral health was associated with greater severity of frailty, functional decline on admission and malnutrition risk. Abnormalities in ROAG domains of voice changes, swallowing difficulty, xerostomia, lips and tongue appearance were more frequently present at greater severity of frailty. Poor oral health was associated with frailty [odds ratio (OR): 1.76, 95% confidence interval (CI) 1.05-2.97; P=0.034]; malnutrition risk [OR: 2.76, 95% CI 1.46-5.19, P=0.002] and functional decline [OR: 1.62, 95% CI 1.01-2.59, P=0.046].

CONCLUSIONS

Poor oral health is significantly associated with frailty, malnutrition risk and functional decline in older inpatients. Oral health evaluation, as part of a comprehensive geriatric assessment may be a target for interventions to improve outcomes. Further research including longitudinal outcomes and effectiveness of specific interventions targeted at oral health are warranted in older adults in the inpatient setting.

Computer vision syndrome: a study of knowledge and practices in university students

INTRODUCTION

Computer vision syndrome (CVS) is a condition in which a person experiences one or more of eye symptoms as a result of prolonged working on a computer.

OBJECTIVES

To determine the prevalence of CVS symptoms, knowledge and practices of computer use in students studying in different universities in Malaysia, and to evaluate the association of various factors in computer use with the occurrence of symptoms.

MATERIAL AND METHODS

In a cross sectional, questionnaire survey study, data was collected in college students regarding the demography, use of spectacles, duration of daily continuous use of computer, symptoms of CVS, preventive measures taken to reduce the symptoms, use of radiation filter on the computer screen, and lighting in the room.

RESULTS

A total of 795 students, aged between 18 and 25 years, from five universities in Malaysia were surveyed. The prevalence of symptoms of CVS (one or more) was found to be 89.9%; the most disturbing symptom was headache (19.7%) followed by eye strain (16.4%). Students who used computer for more than 2 hours per day experienced significantly more symptoms of CVS (p=0.0001). Looking at far objects in-between the work was significantly (p=0.0008) associated with less frequency of CVS symptoms. The use of radiation filter on the screen (p=0.6777) did not help in reducing the CVS symptoms.

CONCLUSION

Ninety percent of university students in Malaysia experienced symptoms related to CVS, which was seen more often in those who used computer for more than 2 hours continuously per day.

Combined heart-liver transplantation with extended cardiopulmonary bypass

We report a case of combined heart and liver transplantation for familial amyloid polyneuropathy. This is the first such combined transplant performed in Asia, and differs from previously described cases, in that cardiopulmonary bypass was continued at partial flow during liver transplantation in our case. This was done in order to provide haemodynamic support to the cardiac graft and to protect it from the impending reperfusion insult that frequently accompanies liver transplantation. The utility of this management course is discussed, along with its actual and potential complications. We also describe the impact of a lung-protective ventilation strategy employed during cardiac transplantation.

Nutritional assessment in an Asian nursing home and its association with mortality

OBJECTIVE

To study the nutritional status of nursing home residents in a multi-racial Asian society and its role in predicting short-term mortality independent of functional status and comorbidities.

DESIGN

Cross-sectional study with prospective collection of mortality data.

SETTING

Nursing home facility in Singapore.

SUBJECTS

A total of 154 patients (mean age 77 +/- 12 years, 53.2% women).

METHODS

We evaluated the demographic details, Mini Nutritional Assessment (MNA) scores, body mass index (BMI) and anthropometric measurements of the participants. Functional status and comorbidities were characterized by the modified Barthel Index and Charlson's comorbidity index respectively.

RESULTS

Prevalence of undernutrition were 52% (n= 80) and 39% (n=60) when determined by BMI < 18.5 kg/m2 and MNA <17 respectively. Mortality was 25.3% (n= 39) over 2 years. Baseline factors associated with mortality include increased age, low Barthel's score, BMI < 18.5 kg/m2 and MNA < 17 (OR= 1.05, 1.01, 3.08 and 3.03 respectively, all p < 0.05). The association between low BMI and mortality remained significant (p=0.027) after adjustment for patient's age, gender, Barthel's and Charlson's scores, and prior nutritional intervention, but the association between MNA and mortality was diminished (p=0.106).

CONCLUSION

There was a high prevalence of undernutrition in this nursing home population, and the diagnosis is an important predictor of mortality. Formal nutritional screening and targeted interventions may improve important clinical outcomes.

The p53 knowledgebase: an integrated information resource for p53 research

The p53 tumor suppressor protein plays a central role in maintaining genomic integrity by occupying a nodal point in the DNA damage control pathway. Here it integrates a wide variety of signals, responding in one of several ways, that is, cell cycle arrest, senescence or programmed cell death (apoptosis). Mutations in the tumor suppressor gene tp53, which affects the key transcriptional regulatory processes in cell growth and death, occur frequently in cancer and helps explain why p53 has been called the guardian of the genome. There is a vast body of published knowledge on all aspects of p53's role in cancer. To facilitate research, it would be helpful if this information could be collected, curated and updated in a format that is easily accessible to the user community. To this end, we initiated the p53 knowledgebase project (http://p53.bii.a-star.edu.sg). The p53 knowledgebase is a user-friendly web portal incorporating visualization and analysis tools that integrates information from the published literature with other manually curated information to facilitate knowledge discovery. This includes curated information on sequence, structural, mutation, polymorphisms, protein-protein interactions, transcription factors, transcriptional targets, antibodies and post-translational modifications that involve p53. The goal is to collect and maintain all relevant data on p53 and present it in an easily accessible format that will be useful to researchers in the field.

Physical mapping and microsynteny of Brassica rapa ssp. pekinensis genome corresponding to a 222 kbp gene-rich region of Arabidopsis chromosome 4 and partially duplicated on chromosome 5

We constructed a bacterial artificial chromosome (BAC) library, designated as KBrH, from high molecular weight genomic DNA of Brassica rapa ssp. pekinensis (Chinese cabbage). This library, which was constructed using HindIII-cleaved genomic DNA, consists of 56,592 clones with average insert size of 115 kbp. Using a partially duplicated DNA sequence of Arabidopsis, represented by 19 and 9 predicted genes on chromosome 4 and 5, respectively, and BAC clones from the KBrH library, we studied conservation and microsynteny corresponding to the Arabidopsis regions in B. rapa ssp. pekinensis. The BAC contigs assembled according to the Arabidopsis homoeologues revealed triplication and rearrangements in the Chinese cabbage. In general, collinearity of genes in the paralogous segments was maintained, but gene contents were highly variable with interstitial losses. We also used representative BAC clones, from the assembled contigs, as probes and hybridized them on mitotic (metaphase) and/or meiotic (leptotene/pachytene/metaphase I) chromosomes of Chinese cabbage using bicolor fluorescence in situ hybridization. The hybridization pattern physically identified the paralogous segments of the Arabidopsis homoeologues on B. rapa ssp. pekinensis chromosomes. The homoeologous segments corresponding to chromosome 4 of Arabidopsis were located on chromosomes 2, 8 and 7, whereas those of chromosome 5 were present on chromosomes 6, 1 and 4 of B. rapa ssp. pekinensis.

The shooty callus induced by suppression of tobacco CHRK1 receptor-like kinase is a phenocopy of the tobacco genetic tumor

CHRK1 encodes a tobacco receptor-like kinase that contains a chitinase-like sequence in the extracellular domain. In a previous study, CHRK1-suppressed transgenic tobacco plants exhibited pleiotropic developmental abnormalities including spontaneous growth of shooty callus from emerging embryos in the absence of any exogenous hormones. In this study, we show that the CHRK1 shooty callus mimics tobacco genetic tumors in its morphology, physiology, and gene expression profiles. Similar to CHRK1 shooty callus, tobacco genetic tumors exhibit shooty callus morphology and hormone-independent shoot organogenesis. Both the CHRK1 callus and genetic tumors constitutively expressed KNOTTED1-type homeobox genes at the high levels, consistent with their vigorous shoot formation. These two types of calli exhibited cell death phenotypes, accompanied by high H2O2 production, increased ion leakage, and callose accumulation. Consistently, both types of calli constitutively expressed high levels of defense genes induced during pathogen-mediated HR cell death. These results, together with previous reports that both the CHRK1 shooty callus and tobacco genetic tumor contained high levels of cytokinin, indicate that CHRK1 shooty callus is a phenocopy of tobacco genetic tumor. CHRK1-mediated signal transduction may play a role in the formation of the genetic tumor in tobacco.

Construction of a BAC library of Korean ginseng and initial analysis of BAC-end sequences

We estimated the genome size of Korean ginseng (Panax ginseng C.A. Meyer), a medicinal herb, constructed a HindIII BAC library, and analyzed BAC-end sequences to provide an initial characterization of the library. The 1C nuclear DNA content of Korean ginseng was estimated to be 3.33 pg (3.12 x 10(3) Mb). The BAC library consists of 106,368 clones with an average size of 98.61 kb, amounting to 3.34 genome equivalents. Sequencing of 2167 BAC clones generated 2492 BAC-end sequences with an average length of 400 bp. Analysis using BLAST and motif searches revealed that 10.2%, 20.9% and 3.8% of the BAC-end sequences contained protein-coding regions, transposable elements and microsatellites, respectively. A comparison of the functional categories represented by the protein-coding regions found in BAC-end sequences with those of Arabidopsis revealed that proteins pertaining to energy metabolism, subcellular localization, cofactor requirement and transport facilitation were more highly represented in the P. ginseng sample. In addition, a sequence encoding a glucosyltransferase-like protein implicated in the ginsenoside biosynthesis pathway was also found. The majority of the transposable element sequences found belonged to the gypsy type (67.6%), followed by copia (11.7%) and LINE (8.0%) retrotransposons, whereas DNA transposons accounted for only 2.1% of the total in our sequence sample. Higher levels of transposable elements than protein-coding regions suggest that mobile elements have played an important role in the evolution of the genome of Korean ginseng, and contributed significantly to its complexity. We also identified 103 microsatellites with 3-38 repeats in their motifs. The BAC library and BAC-end sequences will serve as a useful resource for physical mapping, positional cloning and genome sequencing of P. ginseng.

SCAR and CAPS mapping of CRb, a gene conferring resistance to Plasmodiophora brassicae in Chinese cabbage ( Brassica rapa ssp. pekinensis)

Clubroot disease, caused by Plasmodiophora brassicae Wor., is highly damaging for Chinese cabbage. The CR (clubroot resistant) Shinki DH (doubled haploid) line of Chinese cabbage carries a single dominant gene, CRb, which confers resistance to the P. brassicae races 2, 4, and 8. An F(2) population derived from a cross between the CR Shinki DH line and a susceptible line, 94SK, was used to map the CRb gene. Inoculation of F(3) families with SSI (single-spore isolate) resulted in a 1:2:1 segregation ratio. Use of the AFLP technique combined with bulked segregant analysis allowed five co-dominant AFLP markers, and four and seven dominant AFLP markers linked in coupling and repulsion, respectively, to be identified. Six of the 16 AFLP markers showing low frequencies of recombination with the CRb locus among 138 F(2) lines were cloned. A reliable conversion procedure allowed five AFLP markers to be successfully converted into CAPS and SCAR markers. An F(2) population (143 plants) was analyzed with these markers and a previously identified SCAR marker, and a genetic map around CRb covering a total distance of 6.75 cM was constructed. One dominant marker, TCR09, was located 0.78 cM from CRb. The remaining markers (TCR05, TCR01, TCR10, TCR08, and TCR03) were located on the other side of CRb, and the nearest of these was TCR05, at a distance of 1.92 cM.

Malnutrition screening in hospitalised patients and its implication on reimbursement

BACKGROUND

Several studies have cited the incidence of malnutrition in hospitals, which is correlated to negative clinical outcomes, to be up to 60%. Data in Singapore, however, are scarce. Its impact on casemix funding is not known.

AIMS

The aims of the present study were to determine the prevalence of malnutrition, the predisposing risk factors and the impact of documentation and coding of malnutrition on casemix funding in a local population in Singapore.

METHODS

Patients admitted to selected wards over a 1-month period were screened for malnutrition. Those at risk were further assessed using subjective global assessment. Logistic regression was used to ascertain the impact of identified factors on malnutrition. Financial impact analysis of coding of malnutrition as a comorbidity was carried out and tested with Wilcoxon signed rank tests.

RESULTS

Six hundred and fifty-eight patients were eligible for screening. The overall prevalence of malnutrition in the selected wards was 14.7% (95% confidence interval (CI): 12.0-17.4%). Old age, the occurrence of cancer and the admitting unit were statistically significant in explaining the occurrence of malnutrition. Coding of malnutrition was found to significantly increase the complexity of 24 of 105 episodes (22.9%) of patient care as measured by expected cost weights (P < 0.001) and expected lengths of stay (P < 0.001). As a result, the expected financing for these 24 patients increased by 59.7%.

CONCLUSIONS

Malnutrition is prevalent in hospitalised medical and surgical patients. Certain clinical factors should heighten awareness and prompt detection for malnutrition. Coding for malnutrition impacts favourably on casemix funding for a subset of malnourished patients.

Alpha-defensin 1 (human neutrophil protein 1) as an antichemotactic agent for human polymorphonuclear leukocytes

Medium conditioned by tumor necrosis factor alpha (TNF-alpha)-stimulated polymorphonuclear leukocytes (PMN) (CM-TNF) suppresses PMN migration. Therefore, we wished to identify the agent(s) in CM-TNF that mediated antichemotactic activity. CM-TNF was fractionated by high-performance liquid chromatography, and one fraction with antichemotactic activity contained the bactericidal protein human neutrophil protein 1 (HNP-1). We showed that HNP-1 suppresses PMN migration to formyl-methionyl-leucyl-phenylalanine but not to interleukin 8.

Inhibition of thymidylate synthase activity by antisense oligodeoxynucleotide and possible role in thymineless treatment

Thymidylate synthase (TS) is an important target for chemotherapeutic treatment of cancer. However, efficacy of TS-targeted anticancer drugs is limited by the development of drug resistance as a result of TS gene amplification. In this work, a phosphorothioated antisense oligonucleotide (ODN), designated ATS-2, was used to suppress cellular synthesis of TS. ATS-2 at 0.2 microM concentration was mixed with lipofectin in a charge ratio of 1:1 and was used to treat the human embryonic kidney (HEK) cell line. A reduction of TS mRNA and protein was achieved. Furthermore, a dose-dependent reduction of cumulative viable cells of up to 98% was observed. Flow cytometer analysis of cell cycle progression indicates that ATS-2-treated cells were arrested and went into apoptosis at the S phase, possibly because of thymidine shortage, suggesting that ATS-2 is specifically effective for dividing cells. When used in combination with the anticancer drug FdUrd, ATS-2 exerted a additive inhibitory effect on cellular proliferation. To elucidate the possible role of cellular thymidine kinase (TdR kinase) in ATS-2 treatment, a second cell line, HeLa, was used. Both HEK and HeLa have similar rates of cell division and ODN uptake. In contrast to HEK, which was shown to have very low levels of TdR kinase activity in [(3)H]thymidine incorporation experiments, [(3)H]thymidine incorporation in HeLa was 15-fold greater than that of HEK. We found that HeLa cells were sensitive to FdUrd but were rather resistant to ATS-2. On the contrary, HEK cells were sensitive to ATS-2 but insensitive to FdUrd. Effects of ATS-2 and FdUrd are, therefore, complementary in thymineless treatment too.

Tyrosine phosphorylation of the Bcl-2-associated protein BNIP-2 by fibroblast growth factor receptor-1 prevents its binding to Cdc42GAP and Cdc42

Fibroblast growth factor (FGF) receptor tyrosine kinases are involved in the regulation of cell growth, development, and differentiation in a variety of tissues. To isolate potential signaling molecules in the FGF signaling pathway, we have initiated a yeast two-hybrid screening using the cytosolic domain of FGF receptor-1 (Flg). Here we report the identification of BNIP-2, a previously cloned Bcl-2- and adenovirus E1B-associated protein, as a putative substrate of the receptor. When cotransfected in 293T cells, BNIP-2 was tyrosine-phosphorylated via Flg, but their interaction was transient and could only be seen by "capture" experiments with catalytically inert kinase mutants. When responsive cells were challenged with basic FGF, endogenous tyrosine-phosphorylated BNIP-2 could be precipitated with a BNIP-2 antibody. In addition, the recombinant BNIP-2 expressed in bacteria could be phosphorylated by active Flg in vitro. BNIP-2 shares a region of homology with the noncatalytic domain of Cdc42GAP, a GTPase-activating protein for the small GTP-binding molecule, Cdc42. We show here that BNIP-2 and Cdc42GAP could directly bind to each other and they also compete for the binding to the same target, Cdc42. Unexpectedly, BNIP-2, either produced as a bacterial recombinant protein or expressed in 293T cells, could stimulate the intrinsic GTPase activity of Cdc42. In all cases, tyrosine phosphorylation of BNIP-2 severely impaired its association with Cdc42GAP and its induced GTPase-activating protein-like activity toward Cdc42. These findings should allow us to further characterize the integration of signaling between receptor tyrosine kinases, GTP-binding molecules, and apoptotic pathways.

Degradation products of factor VIII which can lead to increased immunogenicity

The biochemical and immunochemical aspects of the development of inhibitors with a plasma-derived, double-virus inactivated factor VIII (FVIII) concentrate (marketed as Octavi SDPlus in Germany and Bisinact in Belgium) are described. A total of 12 cases of inhibitor formation (predominantly type II) were reported in Germany, 8 in Belgium but none in Portugal. Initially, the only difference between the non-pasteurised, SD virus-inactivated product Octavi and the pasteurised product Octavi SDPlus appeared to be pasteurisation, though subsequently, the quality of source material for the product was found to differ in different countries. Separation studies revealed the presence of a 40 kDa peptide fragment in some batches. It was subsequently shown that there was a strong correlation between inhibitor development and batches containing the 40 kDa marker, and a relationship between elevated markers of coagulation activation (FPA in particular) and the occurrence of the 40 kDa marker. Further work revealed that analytical methods commonly used for quality control were not suitable to highlight batch-to-batch differences. It was concluded that inhibitor potential (neoantigenicity) in Octavi SDPlus arose due to two effects; degradation of FVIII already present in source material; and heating of unstable FVIII degradation products. In this case, inhibitors were not caused by the overall production process, nor by GMP failures. The problem of inhibitor potential can be avoided if appropriate preventive measures are taken. Further work is needed to prove non-neoantigenicity and to reinforce the scientific findings, and to characterise pilot batches.

Association of atypical protein kinase C isotypes with the docker protein FRS2 in fibroblast growth factor signaling

FRS2 is a docker protein that recruits signaling proteins to the plasma membrane in fibroblast growth factor signal transduction. We report here that FRS2 was associated with PKC lambda when Swiss 3T3 cells were stimulated with basic fibroblast growth factor. PKC zeta, the other member of the atypical PKC subfamily, could also bind FRS2. The association between FRS2 and PKC lambda is likely to be direct as shown by yeast two-hybrid analysis. The C-terminal fragments of FRS2 (amino acid residues 300-508) and SNT2 (amino acids 281-492), an isoform bearing 50% identity to FRS2, interacted with PKC lambda at a region (amino acids 240-562) that encompasses the catalytic domain. In vitro kinase assays revealed neither FRS2 nor SNT2 was a substrate of PKC lambda or zeta. Mutation of the alanine residue (Ala-120) to glutamate in the pseudo-substrate region of PKC lambda results in a constitutively active kinase that exhibited more than 2-fold greater binding to FRS2 in vitro than its "closed" wild-type counterpart. Tyrosine phosphorylation of FRS2 did not affect its binding to the constitutively active PKC lambda mutant, suggesting that the activation of PKC lambda is necessary and sufficient for its association with FRS2. It is likely that FRS2 serves as an anchoring protein for targeting activated atypical PKCs to the cell plasma membrane in signaling pathways.

Cloning and characterization of plastid ribosomal protein S16 gene from potato (Solanum tuberosum L. cv Désirée)

The plastid ribosomal protein s16 (rps16) gene was cloned from potato (Solanum tuberosum L. ssp. tuberosum cv Desiree) by PCR amplification to obtain a new homologous recombination site of plastid transformation. The potato rps16 genomic clone was 1627 bp in size and the coding region was interrupted by an 859 bp intron. Exon I was 40 bp, encoding 13 amino acids and exon II was 227 bp, encoding a 76 amino acid polypeptide. The nucleotide sequence of the rps16 gene from the "Désirée" potato shared perfect identity with the sequence from the "Superior" potato in the coding region. Three nucleotide substitutions, two nucleotide insertions, and one nucleotide deletion were found between the intron sequence of both "Désirée" and "Superior" cultivars. The amino acid sequence of the potato rps16 gene showed a high level of identity with rice, maize, tobacco, and mustard (84-94%) and a relatively low level compared with Bacillus stearothermophilus and E. coli (27-28%). Expression of the rps16 gene was strong in chloroplasts and transcripts were detectable in amyloplasts, suggesting that the rps16 gene is active in nonphotosynthetic plastids as well as in photosynthetic plastids. These results indicate that the potato rps16 gene can be used as a new homologous recombination site of plastid transformation for potato cultivars.

Use of compact, porous units with immobilized ligands with high molecular masses in affinity chromatography and enzymatic conversion of substrates with high and low molecular masses

Different ligands with high molecular masses are immobilized on compact, porous separation units and used for affinity chromatography. In subsequent experiments different enzymes are immobilized and used for converting substrates with low and high molecular masses. Disk or tube with immobilized concanavalin A (ConA) are used as model systems for lectin affinity chromatography. The enzyme glucose oxidase is used as a standard protein to test the ConA units. Subsequently glycoproteins from plasma membranes of rat liver are separated, using units with immobilized ConA. The enzyme dipeptidyl peptidase i.v., which is used as a model protein in the experiments, is enriched about 40-fold in a single step, with a yield of over 90%. The results are only slightly better than those obtained with ConA when it is immobilized on bulk supports. The important improvement lies in the reduction of separation time to only 1 h. Experiments concerning the isolation of monoclonal antibodies against clotting factor VIII (FVIII) are carried out on disks, combining anion-exchange chromatography and protein A affinity chromatography as a model for multidimensional chromatography. Both IgG (bound to the protein A disk) and accompanying proteins (bound to the anion-exchange disk) from mouse ascites fluid are retarded and eluted separately. With the immobilized enzymes invertase and glucose oxidase (GOX) the corresponding substrates with low molecular masses, saccharose and glucose, are converted. It is shown that the amount of immobilized enzyme and the concentration of the substrate are responsible for the extent of the conversion, whereas the flow-rates used in the experiments have no effect at all. The influence of immobilization chemistry was investigated with GOX. Indirect immobilization with ConA as spacer proved to be the best alternative. With trypsin, immobilized on a disk, substrates with high molecular masses are digested in flow-through. For optimal digestion the proteins have to be denatured in the buffer for sodium dodecyl sulfate-polyacrlyamide gel electrophoresis prior to application. In contrast to the conversion of substrates with low molecular masses, flow-rates play an important part in conversion of substrates with high molecular masses. With lower flow-rates a higher degree of digestion is achieved.

Growth factors stimulate tyrosine dephosphorylation of p75 and its dissociation from the SH2 domain of Grb2

The growth factor receptor-binding protein (Grb2) has a key role in initiating the mitogen-activated protein kinase signaling cascade in major cell regulatory pathways. The binding of proteins to the SH2 domain of Grb2 has been reported to occur mainly after they are tyrosine-phosphorylated following receptor activation. Using an in vitro binding assay, immunoprecipitation, and Far Western techniques, we report that in quiescent cells a 75-kDa protein binds directly to the SH2 domain of Grb2. All of the tyrosine-phosphorylated p75 protein co-localizes with Grb2.Sos complex in the cytosolic fraction of the cell in vivo and undergoes tyrosine dephosphorylation when cells are treated with mitogenic ligands such as epidermal, platelet-derived, and fibroblast growth factors, endothelin-1, and bombesin but not tumor necrosis factor-alpha, interferon-alpha and -gamma, interleukein-6, and leukemic inhibitory factor, which are either cell growth inhibitory or not significantly mitogenic. The dephosphorylation of p75 and the ensuing dissociation from Grb2 is rapid, occurring within 30 s following mitogenic stimulation by ligands such as epidermal growth factor, suggesting p75 to be an early component in the signal transduction pathways involving Grb2.

SHP2 associates directly with tyrosine phosphorylated p90 (SNT) protein in FGF-stimulated cells

In a number of cell lines responsive to basic fibroblast growth factor (bFGF), two major tyrosine phosphorylated proteins, of molecular weights around 120kDa and 90kDa, are precipitated along with the tyrosine phosphatase SHP2 from the lysates of stimulated cells. The docker protein Gab-1 represents at least part of the 120kDa protein(s). The p90 protein was identified as the SNT protein. The two SH2 domains of SHP2 bind directly and synergistically to tyrosine phosphorylated SNT. Tyrosine phosphorylated SNT does not bind SHP1 and does not appear to be an in vivo substrate of SHP2 but is likely to function as an adapter protein in FGF-signalling.

The presence of arginine vasopressin and its mRNA in rat choroid plexus epithelium

Arginine vasopressin (AVP) plays an important role in the regulation of secretory function and hemodynamics of choroid plexus, the primary site of cerebrospinal fluid (CSF) production. In the present study, localization of AVP and its transcripts in choroid plexus of adult male Sprague-Dawley rats was studied by immunohistochemistry and in situ hybridization histochemistry, respectively. For immunohistochemical analysis, AVP-specific polyclonal rabbit antibody was employed. Plasmid, pGrVP, containing a 232-bp fragment of rat AVP cDNA encoding the C-terminus of proAVP, was used as a probe to detect AVP mRNA. AVP-immunoreactive product was predominantly localized close to the apical (CSF-facing) membrane of choroidal epithelium while AVP transcripts were distributed throughout the cytoplasm of the cells. Our findings indicate that AVP is synthesized in choroid plexus epithelium, which suggests autocrine and/or paracrine actions of this peptide in choroidal tissue.

TuAg.1 is the liver isoform of the rat colon tumor-associated antigen pE4 and a member of the immunoglobulin-like supergene family

TuAg.1 is a tumor-associated membrane glycoprotein first identified in rat hepatocellular carcinoma by monoclonal antibodies (mAbs) 324.5 and 324.9. This oncofetal antigen is also expressed by hepatocytes in cell culture but not normal adult hepatocytes in vivo. Affinity chromatography and preparative continuous elution slab-gel electrophoresis were used to separate TuAg.1 from co-purified actin and immunoglobulin. TuAg.1 was recovered as a series of bands Mr 82,000-90,000, which were pooled and subjected to CNBr digestion for primary amino acid sequence analysis. Computer database analysis of TuAg.1 peptide sequence revealed homology to the rat colon carcinoma-associated antigen pE4, a member of the immunoglobulin gene superfamily. Oligonucleotide primers derived from sequences shared by TuAg.1 and pE4 were used in reverse transcription-PCR to amplify tumor-specific products corresponding to TuAg.1 cDNA. Northern blot analysis with one of these products confirmed the oncofetal expression of transcripts related to TuAg.1/pE4 and indicated an RNA species of different size expressed only in normal liver. Identity between TuAg.1 and pE4 was further confirmed by immunochemical analysis with mAb 324.5 and mAb E4. Both antibodies were reactive with the same protein on transplantable hepatocellular carcinoma AS30D but recognized different epitopes. The reactivity of human tumor cells with mAb 324.5 and 324.9 indicates the presence of a related TuAg.1 molecule expressed in human neoplasia as well.

Immunohistochemical localization of nitric oxide synthase in rat anterior choroidal artery, stromal blood microvessels, and choroid plexus epithelial cells

Nitric oxide (NO) has recently been shown to regulate blood flow to choroid plexus, a specialized brain structure responsible for production of most of cerebrospinal fluid. In the present study, we used a specific polyclonal rabbit antibody against the neuronal isoform of NO synthase (NOS), a synthetic enzyme for NO, to determine the localization of NOS in the choroid plexus of adult male Sprague-Dawley rats. NOS-containing nerve fibers were found in the anterior choroidal artery and its branches, and in stromal blood microvessels. Chronic denervation experiments indicated that these nerve fibers originate predominantly from the sphenopalatine ganglion. NOS-immunopositive staining was also detected in the cytoplasm of choroidal epithelial cells. NADPH-diaphorase, a histochemical marker for NOS, was found to colocalize with NOS-immunoreactive product in both nerve fibers and choroidal epithelium. Both neuronal and epithelium-derived NO may regulate secretory function and hemodynamics of choroidal tissue.

Rapid purification and monitoring of immunoglobulin M from ascites by perfusion ion-exchange chromatography

A purification and on-line monitoring procedure for IgM was developed. Perfusion ion-exchange chromatography was used for rapid purification of IgM from ascites fluid and hybridoma supernatant. Crude ascites was directly loaded onto an ion exchanger. Due to the complexity of IgM, a two-step ion-exchange procedure had to be developed. This procedure involved a rapid cation-exchange chromatography capture step followed by further purification using anion-exchange chromatography. High linear velocities, in excess of 3500 cm/h, enabled separations to be performed under 5 min. Purity of the final product by SDS-PAGE was shown to be greater than 95%. Furthermore, the antibodies retained biological activity as measured by indirect immunofluorescence (IIF) and ELISA. The IgM peak was also monitored on-line using a novel peak tracking approach. This involved placing an antibody column (specific to the IgM) prior to the ion-exchange column and operating the ion-exchange column with and without the antibody column in-line. The missing peak that is identified by comparing the two chromatograms indicates where the IgM elutes.

Suc1-associated neurotrophic factor target (SNT) protein is a major FGF-stimulated tyrosine phosphorylated 90-kDa protein which binds to the SH2 domain of GRB2

In Swiss 3T3 fibroblasts, basic fibroblast growth factor (bFGF) stimulates the unique tyrosine phosphorylation of a protein complex around 90 kDa, as ascertained by high resolution 2-D PAGE and anti-phosphotyrosine blotting. The majority of this complex consists of the protein(s) designated previously as SNT (suc1-associated neurotrophic factor target). Tyrosine phosphorylated SNT binds to both p13suc1 protein and the SH2 domain of Grb2. Binding of SNT to Grb2 is likely to be mediated through the consensus binding motif, pYXN, on SNT. The binding of SNT to p13suc1 is independent of the pYXN motif. Tyrosine phosphorylated SNT is localised in the plasma membrane where it could form a complex with Grb2 and Sos, enabling the initiation of a novel FGF-specific signalling pathway.

Identification of p90, a prominent tyrosine-phosphorylated protein in fibroblast growth factor-stimulated cells, as 80K-H

Tyrosine phosphorylation of cellular proteins occurs rapidly upon treatment of fibroblasts with acidic or basic fibroblast growth factors (aFGF, bFGF), suggesting a role for protein phosphorylation in the FGF signaling pathway. Stimulation of Swiss 3T3 cells and MRC-5 fibroblasts with bFGF results in the tyrosine phosphorylation of several proteins, of which the most prominent has been designated as p90. The phosphorylation of p90 is observed within 30 s of treating the cells with FGF but not with other growth factors. Microsequencing of p90 resolved on two-dimensional polyacrylamide gel electrophoresis indicated an N-terminal amino acid sequence which corresponded to a protein previously named as 80K-H. Polyclonal antibodies raised against the predicted C terminus of 80K-H recognized p90 on all Western blots. p90 was found to bind specifically to GRB-2-glutathione S-transferase fusion protein and to be immunoreactive with 80K-H antibody. In addition, anti-phosphotyrosine antibodies immunoprecipitated 80K-H from cell lysates of FGF-stimulated but not from control fibroblasts. The biological function of 80K-H is yet unknown. However, from this study and a previous observation of the obligatory dependence of p90 phosphorylation on FGF receptor occupation, it appears that 80K-H is involved in FGF signaling.

cDNA cloning and tissue-specific regulation of expression of rat calcium-binding protein 65/67. Identification as a homologue of annexin VI

We isolated a cDNA encoding the rat membrane-associated 65/67-kDa calcium-binding protein, CBP 65/67, from a lambda ZAP II cDNA-expression library of rat liver by immunoscreening using monospecific polyclonal anti-(CBP 65/67) antibodies and monoclonal anti-(CBP 65/67) IgG. The product of this cDNA expressed in Escherichia coli was confirmed as CBP 65/67 both by immunostaining and by comparison of the molecular mass with the CBP 65/67 isolated from rat liver by SDS/PAGE. The cDNA sequence and the deduced amino acid sequence of CBP 65/67 both show a high degree of identity to human p68 and human calelectrin, which belong to a family of calcium-dependent, membrane-associated, phospholipid-binding proteins, called annexins. This means that CBP 65/67 is a homolog of the two human proteins just mentioned above. We are not aware that a rat annexin VI has previously been isolated and sequenced. The mRNA expression of CBP 65/67 in different rat organs during development was investigated by Northern blot analysis. In adult tissues, high mRNA levels of CBP 65/67 were found in lung, heart, muscle, spleen and especially in thymus and pancreas, whereas in liver, kidney, intestine, stomach and brain only low levels of CBP 65/67 mRNA could be detected. The amount of mRNA during tissue development in kidney, stomach and muscle showed only slight changes. In contrast, a significant increase of CBP 65/67 expression was observed in liver, lung, heart and brain. In most of the organs investigated, the level of mRNA correlated closely with the level of protein expression, indicating that the expression of CBP 65/67 in most organs is controlled primarily at the transcriptional level.

TA1, a highly conserved oncofetal complementary DNA from rat hepatoma, encodes an integral membrane protein associated with liver development, carcinogenesis, and cell activation

Hepatocellular carcinoma is characterized by changes in gene expression associated with cell growth and differentiation. Cell surface antigenic changes have also been described based on differential antibody reactivity between normal and neoplastic liver. We obtained a novel tumor-associated cDNA designated TA1 on the basis of its differential expression between hepatoma cells and normal liver. Sequence analysis predicted a 723-base pair open reading frame with the deduced amino acid sequence encoding an integral membrane protein containing multiple hydrophobic transmembrane domains. Database searches revealed TA1 as the likely rat homologue of E16, a recently cloned human cDNA associated with lymphocyte activation. Although noncoding sequences diverged significantly, the 95% conservation of the predicted proteins between species strongly suggests an important, although as yet undefined, function in normal cells. TA1 transcripts were detected in normal adult rat tissues including testes, brain, ovary, spleen, mammary gland, and uterus with the highest steady-state expression in placenta. Although no expression was detected in normal liver, all rat hepatomas examined expressed an abundant 3.2-kilobase transcript. TA1 expression was closely associated with progression in this tumor model and suggests this molecule, originally linked to cell activation, also plays a role in the malignant phenotype.

Anti-peptide sera against cell-CAM 105 determine high molecular-mass variants of the long isoform in rat hepatocytes

The glycoprotein cell-CAM 105 is a member of the carcinoembryonic-antigen-(CEA)-gene family, involved in cell-cell adhesion of rat hepatocytes and expressed on the cell surface as a long (L) and a short (S) isoform with slightly differing molecular masses and isoelectric points. The cDNA of the L-isoform has been isolated and sequenced, as confirmed by the preparation of specific anti-peptide sera [Lin, S.-H., Culic, O., Flanagan, D. & Hixson, D. C. (1991) Biochem. J. 278, 155-161]. Recently, two additional cDNAs have been sequenced, which possess identical deduced primary structures, including short intracellular domains 10 amino acids in length, which differ from the cytoplasmic domain of the L-isoform specifically in the last four C-terminal amino acids. Here, we report on the production of the polyclonal antiserum [anti-(peptide 2)] by immunization with a synthetic hexapeptide (GGSGSF) corresponding to the unique intracellular C-terminal domain of these short cell-CAM 105 cDNA isoforms. This antiserum was specific in ELISA, immunoblot and immunoprecipitation assays for a protein with the same biochemical properties as the S-isoform of cell-CAM 105 expressed in rat liver. In addition, CNBr peptide maps of the S-isoform and the protein immunoprecipitated with anti-(peptide 2) serum were identical. Together, these results provide strong evidence that anti-(peptide 2) serum is specific for the S-isoform of rat liver cell-CAM 105. In immunoblot analysis on liver plasma membrane extracts prepared without collagenase perfusion, at least seven high molecular-mass proteins were observed which showed strong reactivity with mAbs against extracellular epitopes and L-isoform-specific antibodies but no reactivity with anti-(peptide 2) serum. Like the L-isoform, these proteins are expressed on the cell surface and might represent structural variants of cell-CAM 105.

Application of high-performance membrane chromatography for separation of annexins from the plasma membranes of liver and isolation of monospecific polyclonal antibodies

The separation of annexins, calcium-binding plasma membrane-associated proteins from rat liver and Morris hepatoma 7777 by high-performance membrane chromatography (HPMC) is described. The annexins with low molecular masses, CBP 33 and CBP 35, and the annexin with a high molecular mass, CBP 65/67, can be separated within 10 min from one another by anion-exchange HPMC under non-denaturing conditions. The separation devices used consist of compact, porous disks (QuickDisk) on the one hand and of bundled membranes made of cellulose fibers (MemSep) on the other. Both have been found to be equally well suited for this separation. The annexins obtained in this way are subsequently bound to epoxy-activated porons disks and used for the separation of monospecific polyclonal antibodies against the annexin CBP 65/67.

Improved detection of the early stages of colon cancer by determining both free circulating and immune complex-bound antigens reactive with monoclonal antibody

The measurement of both immune complex-bound and free unbound tumor-associated antigen was evaluated independently on a panel of sera from colon cancer patients by radioimmunoassay (RIA). A monoclonal antibody (mAb 46.3) raised against secreted antigens from human colon cancer cells in vitro was utilized in the RIA. When circulating immune complexes alone were analyzed, the data demonstrated that 5 of 5 (100%) Dukes' A patients and 11 of 16 (69%) Dukes' B patients had elevated levels of immune complexes reactive with mAb 46.3. Analysis of free circulating antigens demonstrated elevated levels of mAb 46.3-reactive antigen present in 5 of 5 (100%) Dukes' A patients and 15 of 16 (95%) Dukes' B patients. However, by analyzing total reactivity, defined by combining results from RIA with free and immune complex-bound antigen, the sensitivity of detection for Dukes' B increased to 16 of 16 (100%). Total antigen levels in sera from patients with benign diseases (ulcerative colitis, Crohn's disease, adenoma) were not significantly different from normal controls. Analysis of both free and bound antigen in RIA is, therefore, a more sensitive indicator than RIA with immune complex alone. For the advanced stages of disease, only 1 of 5 (20%) Dukes' C and 0 of 5 (0%) Dukes' D sera were positive for reactive immune complexes. When the combined RIA was evaluated, 3 of 5 (60%) and 1 of 5 (20%) Dukes' C and D sera, respectively, were positive with mAb 46.3. Taken together, these results show that RIA with mAb 46.3 is a sensitive indicator for the early stages of colon cancer.

Preparative mini-slab gel continuous elution electrophoresis: application for the separation of two isoforms of rat hepatocyte cell adhesion molecule, cell-CAM 105, and its associated proteins

A simple method for performing continuous elution electrophoresis using a mini-slab-gel system has been developed. The high resolving power of this method provides a means to separate complex mixtures of proteins and recover individual peptides in high yields. Recoveries between 89 and 99% were achieved using a single percentage gel to separate a mixture of standard proteins radiolabeled with 125I. Peptide fragments between 2.5 and 60 kDa generated by CNBr digestion of albumin were isolated within 150 min. Application of continuous elution electrophoresis to the purification of proteins associated with the rat hepatocyte cell adhesion molecule, cell-CAM 105, resulted in complete separation of the two predominant isoforms and the purification of three immunologically unrelated proteins that were coisolated during immunoaffinity chromatography.

Calcium-binding proteins 33 kDa, 35 kDa, and 65/67 kDa in normal rat and Morris hepatoma tissues. A biochemical and immunohistochemical study

Polyclonal antibodies were raised against membrane-associated calcium-binding proteins (apparent molecular masses 65000 and 67000 (CBP 65/67) and 33000 and 35000 (CBP 33 and CBP 35)), which were isolated from rat liver and Morris hepatoma. Using immunoblotting, various amounts of CBP 33 and CBP 35 as well as CBP 65/67 were detected in most rat organs. Using alkaline phosphatase and monoclonal-anti-alkaline phosphatase antibodies (APAAP), all the calcium-binding proteins were detected by immunohistochemical techniques in the plasma membranes of many cells, such as vascular endothelial cells, lymphocytes, epididymal principal cells, secretory and excretory duct cells of certain exocrine glands, straight distal tubular cells of the kidney, and in the cytoplasm of muscle cells and fibres as well as nerve cells and chondrocytes, and in connective tissue elements. Immunohistochemical analysis also showed that in polarized epithelial cells, e.g., renal tubular cells, epididymal principal cells or excretory duct cells, these calcium-binding proteins are present exclusively or mostly in the luminal plasma membrane.

Preparative isolation of glycoproteins from plasma membranes of different rat organs

By a combination of high-performance affinity chromatographic (HPAC) methods, several membrane proteins from liver, Morris hepatoma and kidney were isolated. The use of a tandem system, consisting of a concanavalin A (ConA) and a wheat germ agglutinin (WGA) high-performance liquid chromatographic (HPLC) column, as a first purification step allowed the isolation of proteins directly from organ homogenates. In a subsequent step, the membrane proteins can be isolated by simply using a combination of immunoaffinity HPLC and preparative sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). However, with these methods most proteins lose their biological activity. If native proteins are required, a combination of different HPAC methods has to be applied. Several membrane proteins were isolated in milligram amounts under non-denaturing conditions using either HPAC columns or Mem Sep membranes with immobilized lectins, collagen, amino acids, crown ethers or heparin.

Rapid lipid peroxidation in the nuclear fraction of rat liver induced by a diet deficient in choline and methionine

A diet deficient in choline and methionine, known to produce hepatocellular carcinoma in the absence of any added chemical carcinogen, induced lipid peroxidation in the nuclear fraction of the liver when fed to male Fischer 344 rats. This lipid peroxidation was detected within 1 day of feeding the diet by the appearance of diene conjugates and increased progressively up to 3 days. It was prevented completely by the addition of choline chloride to the diet. The close proximity of DNA may make it a possible target for attack by free radicals.