Cigarette advertising and media coverage of smoking and health.
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Bacteriophage T7 DNA replication: a linear replicating intermediate (gradient centrifugation-electron microscopy-E. coli-DNA partial denaturation).
The T7 chromosome in the first round of replication is a Y-shaped DNA rod. Thus, it differs from previously observed bacterial and viral replicating chromosomes that are circular.
Centrifugation, Density Gradient↗
Initiation and reinitiation of DNA synthesis during replication of bacteriophage T7.
In its first round of replication, the T7 chromosome follows a simple pattern, as viewed in the electron microscope. The iniation of DNA synthesis occurs about 17% from the genetic left end of the viral DNA rod. Bidirectional DNA synthesis from this origin then generates a replicating intermediate that we call an "eye form." In the eye form, when synthesis in the leftward direction reaches the left end of the viral chromosome, the molecule is converted into a Y-shaped replicating rod. The remaining growing point continues synthesis rightward, until presumably it runs off the right end of the DNA rod, thus terminating replication. Numerous T7 chromosomes were found in which a second round of replication had begun before the first round had finished. Analysis of these reinitiated DNA molecules showed that the second round of replication, like the first, began 17% from the end of the chromosome and involved bidirectional DNA synthesis.
Centrifugation, Density Gradient↗
Production of immunologically active surface antigens of hepatitis B virus by Escherichia coli.
Several plasmids have been constructed which direct the synthesis of hepatitis B virus surface antigens in Escherichia coli either as the native polypeptide or fused to other plasmid encoded polypeptides. When injected into rabbits, extracts from bacteria carrying some of these plasmids induced the synthesis of antibodies to the antigens even though the extracts did not give satisfactory positive results in radioimmunoassay for them. Either the NH2-terminal segment or the COOH-terminal segment of the surface antigens alone was sufficient to elicit the immune response, but antibodies against the two segments showed different specificities. The results emphasize the value of an in vivo assay for the presence of antigens in crude cell extracts and illustrate the feasibility of this type of screening with laboratory animals.
Antibody Specificity↗
Sequence of a cDNA encoding pancreatic preprosomatostatin-22.
We report the nucleotide sequence of a precursor to somatostatin that upon proteolytic processing may give rise to a hormone of 22 amino acids. The nucleotide sequence of a cDNA from the channel catfish (Ictalurus punctatus) encodes a precursor to somatostatin that is 105 amino acids (Mr, 11,500). The cDNA coding for somatostatin-22 consists of 36 nucleotides in the 5' untranslated region, 315 nucleotides that code for the precursor to somatostatin-22, 269 nucleotides at the 3' untranslated region, and a variable length of poly(A). The putative preprohormone contains a sequence of hydrophobic amino acids at the amino terminus that has the properties of a "signal" peptide. A connecting sequence of approximately 57 amino acids is followed by a single Arg-Arg sequence, which immediately precedes the hormone. Somatostatin-22 is homologous to somatostatin-14 in 7 of the 14 amino acids, including the Phe-Trp-Lys sequence. Hybridization selection of mRNA, followed by its translation in a wheat germ cell-free system, resulted in the synthesis of a single polypeptide having a molecular weight of approximately 10,000 as estimated on Na-DodSO4/polyacrylamide gels.
Amino Acid Sequence↗
Hepatitis B virus core antigen: synthesis in Escherichia coli and application in diagnosis.
Fragments of hepatitis B virus DNA cloned in plasmid pBR322 carrying the gene for the viral core antigen have been placed under the control of the lac promoter of Escherichia coli. Several of the new recombinants direct higher levels of synthesis of the antigen, but the degree of enhancement varies with the different structures of the plasmids and hence the mRNAs produced. The antigen in crude bacterial lysates is a satisfactory diagnostic reagent for antibodies to the core antigen in serum samples.
Antibodies, Viral↗
Use of synthetic peptides to identify an N-terminal epitope on mouse gamma interferon that may be involved in function.
We previously have assigned N-terminal specificity to three hamster monoclonal antibodies (mAbs I, II, and III) produced to mouse recombinant gamma interferon (IFN-gamma), based on the ability of the N-terminal peptide IFN-gamma-(1-39) to block binding of 125I-labeled IFN-gamma (125I-IFN-gamma) and on the ability of these antibodies to bind 125I-IFN-gamma-(1-39). Only mAb I blocked function and binding to the IFN-gamma receptor, suggesting that it may bind to a region of the molecule involved in interaction with the receptor. To further define the epitope specificities of the antibodies, a series of N-terminal peptides were synthesized and tested for their ability to block antibody binding of 125I-IFN-gamma. Peptides IFN-gamma-(1-39), IFN-gamma-(1-20), IFN-gamma-(3-20), and IFN-gamma-(5-20) inhibited binding of 125I-IFN-gamma by mAb I in order of decreasing effectiveness, while peptide IFN-gamma-(7-20) was without effect. Peptides IFN-gamma-(1-39), IFN-gamma-(1-20), and IFN-gamma-(3-20) also inhibited binding of 125I-IFN-gamma by mAb II but were less effective when compared with their inhibition of mAb I. IFN-gamma-(5-20) and IFN-gamma-(7-20) did not inhibit binding by mAb II. Peptides IFN-gamma-(1-10), IFN-gamma-(10-30), and IFN-gamma-(21-44) did not inhibit either mAb I or mAb II. While IFN-gamma-(1-39) and IFN-gamma-(10-30) inhibited binding by mAb III, neither IFN-gamma-(1-20) nor any of its truncated forms were inhibitory. All three antibodies had similar Kd values for 125I-IFN-gamma. A prediction of the secondary structure of the molecule and the peptide inhibition data suggest that the epitope (possible receptor binding region) for mAb I involves a loop in the area containing residues 12-20, with sequences N-terminal to these residues possibly stabilizing the loop conformation. Direct evidence that the N-terminal 1-39 region of IFN-gamma is important in receptor binding was the observation that IFN-gamma-(1-39), but not the C-terminal IFN-gamma-(95-133), competed with 125I-IFN-gamma for the receptor on mouse L cells. IFN-gamma-(1-39) also specifically blocked IFN-gamma antiviral activity at concentrations that blocked binding to the receptor. The fact that IFN-gamma-(1-39) was the only peptide that blocked both IFN-gamma binding to receptor and function is consistent with the antibody competition data, where it was the most effective peptide in blocking binding of 125I-IFN-gamma by the N-terminal-specific mAbs. The combination of peptide mapping of epitope specificities and receptor competition should further help define the structural basis for IFN-gamma action.
Animals↗
Presence of the mu3 opiate receptor in endothelial cells. Coupling to nitric oxide production and vasodilation.
Initial confinement of opiate receptors to the nervous system has recently been broadened to several other cell types. Based on the well established hypotensive effect of morphine, we hypothesized that endothelial cells may represent a target for this opiate substance. Endothelial cells (human arterial and rat microvascular) contain a high affinity, saturable opiate binding site presumed to mediate the morphine effects that is stereoselectively and characteristically antagonized by naloxone. This opiate alkaloid-specific binding site is insensitive to opioid peptides. It is, therefore, considered to be the same subtype of opiate receptor (designated mu3) used in the mediation of morphine in other cell types exhibiting the same binding profile. Experiments with endothelial cultures and the aortic ring of rats cultured in vitro demonstrate that morphine exerts direct modulatory control over the activities of endothelial cells, which leads to vasodilation. It induces the production of nitric oxide, a process that is sensitive to naloxone antagonism and nitric oxide synthase inhibition. In contrast with that of opiates, the administration of opioid peptides does not induce nitric oxide production by endothelial cells. In conclusion, the data presented above reveal a novel site of morphine action, endothelial cells, where a mu3 receptor is coupled to nitric oxide release and vasodilation.
Animals↗
Women in media in the Philippines: from stereotype to liberation.
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Asia↗
Women and the media in South Asia.
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Asia↗
Effects of maternal environment and postnatal multiple testing on adult rat offspring.
Two hundred thirty Wistar rats, obtained from undisturbed mothers and from mothers that were exposed to temporary isolation and/or laparotomy, were randomly exposed to three of the following specific behavioral test procedures: (1) conditioned avoidance response, (2) water T-maze, (3) open field, (4) activity wheel, (5) forelimb hanging, and (6) swimming. Performance of the offspring was examined during adulthood. Effects of previous testing on later testing performance and performance correlation between the two testing procedures were analyzed. The results indicate that (1) the maternal conditions manipulated in this study do not significantly affect behavior in the adult offspring (p greater than 0.05), and (2) performance of a previous task by the offspring does not significantly alter, and is not correlated with, the performance level on a second, unrelated task. Therefore, within these parameters, rats can be used for multiple testing procedures in a more practical and less costly means of behavioral investigation. These findings may be useful in the development and refinement of postnatal developmental toxicological screening procedures for agents that may be harmful to humans.
Animals↗
Two peptides derived from the nerve growth factor precursor are biologically active.
This report provides evidence that the proregion of the NGF precursor protein contains two novel bioactive peptides. The presence of pairs of basic amino acid (aa) residues in the NGF proregion suggests that two or three peptides other than NGF may be generated by proteolytic cleavage. Synthetic peptides of 29 aa (LIP1) and 38aa (LIP2) corresponding to the sequences -71 to -43 and -40 to -3 of the proNGF, respectively, were used in this study. ELISA specific for these two peptides revealed their presence in the rat intestine. LIP1 was localized by immunohistochemistry in endocrine cells of the intestinal epithelium, and LIP2 was immunoprecipitated from an intestinal extract. We also provide evidence for the presence of specific receptors for LIP2 in several cell lines. Scatchard analysis indicated the presence of a low affinity binding site with a Kd of approximately 10(-7) M and a high affinity binding site of 10(-9) M. Cross-linking studies revealed receptor forms of about 140 kD and 93 kD in a prostatic adenocarcinoma cell line. LIP1 and LIP2 induced rapid F-actin redistribution in PC12 cells within 2 min of incubation, which suggests a role of LIP1 and LIP2 in the process of neurite outgrowth. Furthermore, both propeptides induced rapid tyrosine phosphorylation of the Trk protein in both prostatic adenocarcinoma cells and PC12 cells, thus implicating trk in their mechanism of action. These results support our hypothesis that two peptides within the NGF precursor protein are biologically active.
Actins↗
Steric relationship of amino-terminal and carboxy-terminal domains of murine interferon-gamma as assessed by monoclonal antibodies.
Spleen cells from a hamster immunized with murine interferon-gamma (IFN-gamma) carboxy-terminal (95-133) synthetic peptide [IFN-gamma (95-133)] conjugated to keyhole limpet hemocyanin (KLH) were fused with mouse myeloma cells, resulting in the production of an anti-IFN-gamma (95-133) monoclonal antibody, which reacted with IFN-gamma. This monoclonal antibody bound [125I]IFN-gamma in a dose-dependent and reversible fashion, and neutralized the antiviral and macrophage priming activities of IFN-gamma. Antibody-antibody competition for [125I]IFN-gamma binding, using this carboxy-terminal-specific antibody and two previously described amino-terminal-specific monoclonal antibodies, indicated that the carboxy-terminal-specific monoclonal antibody competed only with itself and that the two amino-terminal-specific monoclonal antibodies similarly competed only with each other for [125I]IFN-gamma. The data suggest that the amino- and carboxy-terminal IFN-gamma domains important for function are sterically distant from one another, and suggest the intriguing possibility that interaction of IFN-gamma with its receptor may involve more than one binding site on the IFN-gamma molecule.
Animals↗
Changes in functional status attributable to hip fracture: a comparison of hip fracture patients to community-dwelling aged.
Disability attributable to hip fracture regarding activities of daily living was evaluated by comparing 594 hip fracture patients entering eight hospitals in Baltimore, Maryland, in 1990-1991 with community-dwelling aged from the Established Populations for Epidemiologic Studies of the Elderly (EPESE) cohort matched on age, sex, and walking ability. Subjects were assessed at baseline (prefracture report for patients), 12 months, and 24 months. At baseline, 26% of both groups had walking disability, 12-14% had transferring disability, and 6-8% evidenced grooming disability. At 12 and 24 months, about 50% of hip fracture patients were walking disabled compared with 21-29% of EPESE respondents after the authors controlled for age, sex, comorbidities, and functional status (excess disability attributable to hip fracture, i.e., attributable disability, of 26 additional cases of disability per 100 persons in the hip fracture cohort during follow-up). Likewise, hip fracture patients experienced more disability regarding transferring (38-39% vs. 10-18%; attributable disability, approximately 22 cases per 100 persons) and grooming (17-19% vs. 7-15%; attributable disability, approximately six cases per 100 persons). Thus, results showed that hip fracture patients had substantially more activities of daily living disability than that explained by aging over 24 months.
Activities of Daily Living↗
The predictors of surgical procedure and the effects on functional recovery in elderly with subcapital fractures.
BACKGROUND: It has been demonstrated that the majority of hip fracture patients do not regain their prefracture level of functioning and usually decline in function following fracture. Little is known about the effectiveness of surgical procedure performed (hemiarthroplasty vs internal fixation) on functional recovery of subcapital fracture patients. This study examines the factors related to the type of the surgical procedure chosen and the effect of this selection on physical activities of daily living (PADL) and instrumental activities of daily living (IADL). METHODS: The sample consists of 312 patients with subcapital fractures age 65 and older admitted from the community to one of seven Baltimore area hospitals between 1984 and 1986. Baseline information was obtained during hospitalization through structured interviews with both patients and their significant others (proxy). The follow-up interviews were administered to proxies at two months, six months, and one year after discharge from hospital. Information on disease diagnoses, fracture severity, and surgical procedures performed was obtained from medical charts. RESULTS: Patients with a displaced fracture were seven times more likely to receive a hemiarthroplasty (OR = 7.0, 95% CI 3.7-13.1). During the short-term recovery (2 months after surgery), patients who received hemiarthroplasty were doing better in transferring, meal preparation, and shopping than those who received internal fixation. For the long-term functional recovery (one year), the overall PADL and IADL functions were not statistically significantly different between the two surgical procedures performed. CONCLUSIONS: The severity of fracture was found to be the most important determinant of surgical procedure. Patients with a subcapital fracture who received hemiarthroplasty tended to have a better functional recovery in the short term. Further study of other benefits of using as hemiarthroplasty is needed.
Activities of Daily Living↗
Intertrochanteric versus femoral neck hip fractures: differential characteristics, treatment, and sequelae.
BACKGROUND: More than 220,000 persons 65 years and older fracture a hip every year in the United States. Although hip fractures have been considered as a single, homogeneous condition, there are two major anatomic types of proximal femoral fractures: intertrochanteric and femoral neck. The present study's objective was to determine if the two types of hip fracture have different patient characteristics and sequelae. METHODS: A prospective study of 923 elderly patients admitted to seven Baltimore hospitals for a hip fracture between 1984 and 1986. RESULTS: Patients with intertrochanteric fractures were slightly older, sicker on hospital admission, had longer hospital stays, and were less likely at 2 months postfracture to have recovered activities of daily living than femoral neck fracture patients. Intertrochanteric fracture patients also had higher mortality rates at 2 and 6 months after fracturing. Long-term recovery (1 year) did not differ between fracture type. CONCLUSIONS: It appears that intertrochanteric fracture patients have intrinsic factors (older age, poor health) impacting upon their risk of fracture and ability to recover. Differences in patient characteristics and sequelae do exist between femoral neck and intertrochanteric hip fracture patients that impact upon recovery.
Activities of Daily Living↗
Serum concentrations of steroids, parathyroid hormone, and calcitonin in postmenopausal women during the year following hip fracture: effect of location of fracture and age.
BACKGROUND: Hip fracture in the aged is a major health problem, especially considering the increasing proportion of the elderly in the population. This study examines changes in circulating levels of hormones, which are purported to affect bone metabolism, in response to hip fracture in postmenopausal women. METHODS: Patients consisted of women ages 65 and older who had surgery within 2 days of fracture. Serum samples were obtained at 3, 10, 60, 180, and 360 days postfracture. Healthy women without hip fractures from the same age range served as a control group (n = 17). Hormones were determined by radioimmunoassay. Subjects with fractures in the neck region of the femur (n = 78) were compared to subjects with fractures in the trochanteric region (n = 88). RESULTS: Estrone concentration (47.6 +/- 5.7 pg/mL; mean +/- SEM) at 3 days postfracture was elevated (p < .001) compared to control levels of 20.7 +/- 4.6 pg/mL. By 2 months, levels had declined to control levels. Androstenedione and the adrenal hormones, DHEAS and cortisol, displayed similar responses. Parathyroid hormone (PTH) levels were not significantly different from the control concentration at 3 days following fracture, but increased (p < .001) during the year following fracture. Calcitonin concentrations were much higher (p < .001) 3 days postfracture (42.1 +/- 3.7 pg/mL) compared to controls without fracture (9.8 +/- 3 pg/mL). Except for testosterone, no differences could be attributed to fracture location. Only PTH, with concentrations higher in the older age groups (p < .001), showed an age-related response. CONCLUSIONS: Following hip fracture, there are some dramatic responses in hormones that purportedly are mechanistically important in bone metabolism. These changes include transient increases in steroid hormones, chronic elevations in calcitonin, and rising levels of PTH during the year after fracture.
Aged↗