A murine leukemia virus expressed in aged DBA/2 mice is derived by recombination of the Emv-3 locus and another endogenous gag sequence

Although most inbred strains of mice contain endogenous retroviral sequences, these sequences are usually not capable of producing infectious retroviruses. In some cases, the retroviral sequences are small fragments of viral genomes. In a few cases the sequences for complete retroviruses exist, but contain small defects which prevent the production of infectious virus. While the ability of reversions of these defects to produce retroviruses has been studied by site-directed mutagenesis and chemical-mediated mutagenesis, the presence of spontaneously occurring reversions has not been completely evaluated. We characterized an infectious ecotropic retrovirus spontaneously expressed in aged DBA/2 mice, which carries the complete but defective Emv-3. Although this endogenously produced retrovirus was related to the endogenous Emv-3 sequence, it had undergone recombination with another retroviral sequence to correct the defect which resided in the gag of Emv-3. Thus, recombination of endogenous ecotropic retroviral sequences may be a mechanism to produce infectious retroviruses in adult animals that contributes to pathologic disease.

Mechanisms of caloric restriction affecting aging and disease

Caloric restriction (CR) appears to affect aging by the inhibition of the specific chronic diseases which occur at increasing frequency with age. A common disease in F-344 rats, granulocytic leukemia, appears to have a window where it is sensitive to the effects of CR. Other diseases, such as pituitary adenomas, appear to have a different relationship to growth in the animal. Additionally, a model for the major disease for a number of long-lived strains of mice, lymphoma, which CR effects by inhibiting the expression of the causative agent, is being developed. Evaluation of the effects of CR on neoplasia, degenerative disease and physiological parameters suggests that the major factors in expression of these diseases is the alteration of growth factors, hormonal status, etc., and that these alterations also affect strain-specific pathologies depending on when they are changed in the life span. Effecting different diseases at different times in the life span, long-term CR, by limiting exposure to endogenous growth factors, altering physiological characteristics, and limiting exposure to food toxicants, inhibits the onset of disease, and its sequela, aging.

The detection of D-dimer in plasma by enzyme immunoassay: improved discrimination is obtained with a more specific signal antibody

Most commercial D-dimer enzyme immunoassays employ two antibodies, a fibrin specific capture monoclonal and a less specific antibody cross-reacting with epitopes present on fibrinogen. Two different ELISA systems were compared to test whether this cross-reaction can lead to overestimation of the true levels of cross-linked fibrin derivatives. Both assays used the same D-dimer specific antibody for capture, DD-3B6/22, but utilized signalling antibodies which differed in fibrinogen reactivity. The assays gave low results for 210 normal samples (conventional ELISA, 39 +/- 45 ng/ml; non-fibrinogen reactive ELISA, 23 +/- 20 ng/ml) with a high degree of elevation for 53 patients with active thrombosis (conventional ELISA, 901 +/- 649 ng/ml; non-fibrinogen reactive ELISA, 1,906 +/- 1,725 ng/ml). However, a dramatic difference between results was seen when fibrinogenolysis was induced by treatment of 20 normal plasmas with high levels of t-PA and plasminogen. The D-dimer levels estimated with the conventional fibrinogen-reactive signal antibody rose 25-fold (normal, 36 +/- 27 ng/ml; treated, 833 +/- 272 ng/ml), whereas no increase was obtained with the non-fibrinogen reactive ELISA (normal, 24 +/- 21 ng/ml; treated, 27 +/- 22 ng/ml). These results suggest that a more accurate estimation of D-dimer levels in samples containing high levels of fibrinogen derivatives is achieved in assays incorporating non-fibrinogen reactive antibodies.

The temporal relationships of synthesis and phosphorylation in stress proteins 70 and 90 in aged caloric restricted rats exposed to bleomycin

A single intraperitoneal injection of the human therapeutic drug bleomycin (BL) was administered to three groups of male Fischer 344 rats at time 0, and the incorporation of [35S]methionine ("synthesis") and phosphorylation patterns of stress proteins (sps/hsps) from bone marrow cells were analyzed over time by two-dimensional electrophoresis and fluorography. Two groups of rats, young ad libitum (Y/AL--3 months) and old ad libitum (O/AL--28 months), had free access to rat chow, and a third group of old rats (O/CR--28 months) were maintained on a caloric restricted intake (60% of the AL diet). The administration of BL in Y/AL, O/AL and O/CR animals activated the 35S-labeling of sp 90 which reached a peak at 4 hours. Labeling of sp 90 was significantly greater in Y/AL compared to O/AL, and the incorporation pattern of O/CR was intermediate to Y/AL and O/AL animals. All labeling of sp 90 in each group had disappeared by 10 hours after BL administration. Stress protein 70x (inducible form) in these three animal groups displayed a similar pattern of 35S-incorporation, but the amount of labeling was less than that of sp 90. No labeling of sp 70x remained by 13 hours after BL administration. Phosphorylation ([32P] phosphate incorporation) of sp 90 reached a maximum level at 2 hours in all animals, and 32P-labeling in Y/AL was significantly increased over O/AL and O/CR with an intermediate level found in O/CR animals. The turnover rate (phosphorylation/dephosphorylation) of sp 90 induced by BL was significantly suppressed and temporarily extended in O/AL as compared with O/CR, which implied that CR not only increased incorporation of sp 90, but also enhanced a utilization of the phosphate pool very similar to that seen in Y/AL animals.

Ocular melanoma in childhood

A case of primary ocular melanoma of the iris in a 10 year old girl is reported. Primary melanoma of the eye is exceedingly rare in childhood. The incidence and risk factors for ocular melanoma are discussed and possible reasons why this tumour is so uncommon in younger age groups are considered.

SCH 45752--an inhibitor of calmodulin-sensitive cyclic nucleotide phosphodiesterase activity

A highly potent inhibitor of calmodulin-sensitive phosphodiesterase (PDE) activity was isolated from the culture broth of an unidentified fungal isolate, SCF-125. A chemically defined medium was developed for production of this compound. The PDE inhibitor was isolated from the fermentation filtrate by adsorption on a macro-reticular resin and further purified by gel filtration chromatography and reverse-phase HPLC. The major PDE inhibitor was identified as cephalochromin, a bis-naphthopyrone, by spectral data analysis. The compound, SCH 45752, inhibited calmodulin-sensitive PDE activities with IC50 values of 40-47 nM. It inhibited the activities of calmodulin-independent PDE and various protein kinases with higher IC50 values (2-40 microM). SCH 45752 does not appear to be a calmodulin antagonist. Furthermore, SCH 45752 affects smooth muscle contraction at a concentration of 30 microM; it potentiated the relaxing effect of sodium nitroprusside on carotid artery media contracted by histamine. Thus SCH 45752 is one of the most potent inhibitors of calmodulin-sensitive PDE activity known, and it is capable of exerting a pharmacological effect in at least one intact tissue model.

Dietary alteration in the rates of cancer and aging

Both variation of diet and comparative analysis are used to evaluate the effects of nutrition on mortality and cancer. The effects of caloric restriction (CR) are compared in multiple strains raised under similar conditions for a diet developed to assist breeding, and for a standard diet. A standard analysis, using "aging rates," is of limited use for understanding the effects of CR in delaying mortality in certain strains. However, when the effect of the diets on body weight and the known effects on sex-specific P-450 isoenzyme expression are compared, these effects suggest a mechanism for the action of CR. By comparative analysis, the effect of CR on tumor pathology suggests that the same mechanisms responsible for inhibiting reproduction may be responsible for delaying the aging-related increase in incidence of diseases. Based on these data, the adaptive/longevity-related process theory of CR is modified to incorporate aspects of the disposable soma theory of aging, as well as pleiotropism.

Effects of aging and dietary restriction on DNA polymerases: gene expression, enzyme fidelity, and DNA excision repair

Hepatic DNA polymerases isolated from young and old C57BL/6N mice fed ad libitum or calorically restricted differed in chromatographic characteristics, binding affinity for DNA template-primer, specific activity, and fidelity of synthesis. DNA polymerase alpha total and specific activity declined slightly, while the nucleotide misincorporation frequency increased dramatically, with increased age of the donor animals. A positive correlation was observed between polymerase alpha specific activity and the affinity of enzyme binding to activated DNA template-primer. Both the age-associated decline in enzyme activity and the decrease in fidelity of synthesis were modified by dietary restriction, with higher specific activity levels and lower misincorporation frequencies for DNA polymerases from dietarily restricted animals compared with ad libitum animals of all ages. Fidelity of both DNA polymerase alpha and beta increased following treatment with the phosphoinositide hydrolysis product inositol-1,4-bisphosphate. The data suggest that dietary restriction could play an important role in decreasing the age-associated decline in function of physiological systems sensitive to decreased or defective DNA synthesis.

Glucose malabsorption associated with rapid intestinal transit

Twenty-five patients with chronic diarrhea were studied with a combined glucose-hydrogen breath test (GHBT) and nuclear transit scan to elucidate the role of abnormal transit in the pathogenesis of diarrhea. Eight of the 25 patients demonstrated both a rapid orocecal transit time by nuclear scan (less than 30 min) and a positive hydrogen breath test (greater than 20 ppm increase in H2 after a 50-g glucose challenge). Because these individuals had no anatomic abnormalities predisposing to small bowel bacterial overgrowth, it is probable that they demonstrated colonic bacterial metabolism of carbohydrate secondary to glucose malabsorption associated with rapid small bowel transit. The eight patients exhibited some form of autonomic dysfunction generally related to systemic disease. Thus, there may be a subset of patients with chronic diarrhea related to rapid intestinal transit. A combined GHBT-nuclear transit scan permits accurate identification of such individuals and improves the accuracy of hydrogen breath tests in the diagnosis of bacterial overgrowth.

Ethanol inhibits interferon-gamma secretion by human peripheral lymphocytes

Clinical and epidemiological evidence exists that subjects who chronically abuse alcohol are disposed to infections and certain types of cancer. In vitro inhibition of mitogen-induced lymphocyte proliferation has been shown suggesting a direct immunosuppressive effect of ethanol. Using human peripheral blood mononuclear cells we could demonstrate in vitro for the first time that even low ethanol concentrations of 6 and 12.5 mM significantly inhibit spontaneous and mitogen-induced secretion of interferon-gamma. This effect was more pronounced with lower mitogen stimulation and it increased in a dose dependent manner when higher ethanol concentrations were used. Inhibition of cell proliferation as measured by 3H-thymidine incorporation did not parallel the inhibition of interferon-gamma secretion. As this lymphokine exerts a great number of immunostimulating effects, diminished secretion might well contribute to the immune defect observed in alcoholics.

Nonspecific immunostimulation with low doses of cyclophosphamide (LDCY), thymostimulin, and Echinacea purpurea extracts (echinacin) in patients with far advanced colorectal cancers: preliminary results

Outpatients (n = 15) with metastasizing far advanced colorectal cancers received immunotherapy consisting of low-dose cyclophosphamide (LDCY) 300 mg/m2 every 28 days i.v., thymostimulin 30 mg/m2, days 3-10 after low-dose cyclophosphamide i.m. once daily, then twice a week, and echinacin 60 mg/m2 together with thymostimulin i.m. All patients had had previous surgery and/or chemotherapy and had progressive disease upon entering the study. Two months after onset of therapy a partial tumor regression was documented in one and a stable disease in 6 other patients by abdominal ultrasonography, decrease of the tumor markers carcinoembryonic antigen (CEA), CA 19-9, CA 15-3, and/or chest roentgenography, which may also be attributed to the natural course of disease. Mean survival time was 4 months, 2 patients survived for more than 8 months. Immunotherapy was well tolerated by all patients without side effects.

Isolation, localization, and physical mapping of a highly polymorphic locus on human chromosome 11q13

A highly polymorphic repetitive sequence, D11S533, was isolated by oligonucleotide hybridization from an arrayed chromosome 11q-specific cosmid library. The DNA sequence of this element was determined and found to consist of a repetitive degenerate hexanucleotide sequence [T(Pu)T(Pu)T(Pu)]n extending over 438 bp. Southern blot analysis demonstrated that this element is relatively unique in the human genome. This sequence can be detected by amplification using the polymerase chain reaction (PCR) with oligonucleotide primers complementary to unique sequences flanking the repetitive element. This sequence displays a high degree of polymorphism, and analysis of 15 individuals demonstrated at least 10 alleles ranging in size from 300 to 900 bp. Fluorescence in situ hybridization was used to localize this sequence to 11q13 (FLpter 0.60 +/- 0.02). Pulsed-field gel electrophoresis and the isolation of yeast artificial chromosomes established the long-range physical map surrounding the locus. Because various alleles of this polymorphic sequence can be easily detected by PCR amplification, this probe has potential usefulness in genetic linkage mapping as well as identity testing.

Effects of aging and dietary restriction on DNA polymerase expression in mice

DNA polymerase alpha was isolated from livers of 6-month-, 16-month-, or 26-month-old mice fed ad libitum, or calorically restricted. The enzymes differed in chromatographic characteristics, binding affinity for DNA, and activity, with both total activity and specific activity of DNA polymerase alpha decreasing as a function of age. A positive correlation was observed between polymerase alpha specific activity and the affinity of enzyme binding to activated DNA template-primer. The age-associated decline in enzyme activity was modified by dietary restriction, with measurably higher activity seen for polymerases from dietary restricted animals compared with ad libitum animals of all ages. The data suggest that dietary restriction could act to delay the age-associated decrease in cellular capacity for DNA synthesis, which may play a significant role in prolonging the onset of age-related diseases in which decreased DNA synthesis is a potential component.

Soluble interleukin-2 receptor and soluble CD8 in liver cirrhosis and obstructive jaundice

Activated lymphocytes secrete soluble interleukin-2 receptor (sIL-2R); CD8-positive lymphocytes secrete soluble CD8 (sCD8). Liver dysfunction in cirrhosis and obstructive jaundice is known to result in depressed cellular immunity. To evaluate whether this is due to real inactivation of the immune system, we measured sIL-2R and sCD8 in the serum of 46 patients with liver cirrhosis, 25 patients with obstructive jaundice, 32 patients with alcoholic liver disease without evidence of cirrhosis, 23 healthy persons and 43 patients with unrelated disease. sIL-2R in patients with cirrhosis (mean +/- s.e.m. 1499 +/- 140 U/ml) and obstructive jaundice (1517 +/- 204) was significantly increased compared with healthy subjects (363 +/- 29) and patients with unrelated diseases (685 +/- 92); sCD8 was significantly increased in patients with cirrhosis (737 +/- 63) but not in patients with obstructive jaundice (419 +/- 32) compared with healthy subjects (322 +/- 23) and patients with unrelated diseases (375 +/- 22). No difference was found between patients with cirrhosis due to alcohol abuse (n = 15) and chronic hepatitis B (n = 6). The Child-Pugh score had no significant influence on the sIL-2R or sCD8 value. In obstructive jaundice, sIL-2R correlated with alkaline phosphatase as marker of cholestasis (r = 0.43). These data show that in spite of the apparent depressed cellular immune defense both in liver cirrhosis and obstructive jaundice there is a general activation of the immune system but the CD8+ cell compartment is only activated in liver cirrhosis. The great changes of sIL-2R and sCD8 in liver dysfunction are important for the interpretation of studies using these serum proteins as markers for immune activation.

Complications of diagnostic gastrointestinal endoscopy

Undesired side effects and complications of gastrointestinal endoscopy and premedication are rare events. However, this is true only of endoscopic units with experienced investigators, modern equipment and monitoring. The complication rate of upper gastrointestinal endoscopy is about 0.1% with cardiopulmonary events predominating. The typical complication of colonoscopy is perforation, seen in 0.2%. The relevant ERCP specific complication is acute pancreatitis in about 1%, followed by acute cholangitis. The most serious complications of laparoscopy are hemorrhage from the liver biopsy site, bleeding from abdominal wall varices, and perforation of the colon. The cardiopulmonary mortality is low for upper gastrointestinal endoscopy as well as for colonoscopy (1 death/20,000 procedures). Premedication, chronic obstructive pulmonary disease, coronary heart disease, valvular heart disease and, last but not least, advanced age, must be considered risk factors for the development of complications of gastrointestinal endoscopy. Balanced indication, particularly in the elderly patient, should be the consequence. If possible, endoscopy should be performed without sedatives. If premedication is necessary, it should be used sparingly. Not only patients at high risk for the development of cardiopulmonary complications, but all patients undergoing endoscopy must be carefully monitored after premedication, during and after endoscopy. The non-invasive procedure of pulse-oximetry is appropriate for continuous monitoring of arterial oxygen saturation in patients with cardiopulmonary diseases, irrespective of their premedication status. Antibiotic prophylaxis is recommended in patients with valvular heart disease or prosthetic valves. Standardized cleaning and disinfection of the instruments is of great importance to avoid hepatitis B or HIV transfer.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of thyrotropin-releasing hormone on immune functions of peripheral blood mononuclear cells

The tripeptide thyrotropin-releasing hormone (TRH) works as a hypothalamic hormone, but is found also outside the brain in intrinsic nerve fibers of the gastrointestinal tract. There is evidence that TRH modulates the activity of immunocompetent cells, although there are only very few data on TRH-mediated immune effector functions. Since we could recently show that TRH inhibits monocyte activities we were also interested in other possible TRH modulated immune functions. Peripheral blood mononuclear cells (PBMC) from ten healthy subjects were cultured for 7 days and pulsed with 0.125 and 0.250 microgram/ml Pokeweed mitogen (PWM). 10(-12) to 10(-6) M TRH was added simultaneously with PWM. Lymphocyte proliferation [(3H]thymidine incorporation), interferon-gamma (IFN-gamma) activity (RIA) and immunoglobulin activities (IgG, IgM, IgA; ELISA) were determined in the supernatants. We could demonstrate a TRH-dependent decrease in PWM-pulsed IgG activity with significant (alpha = 0.05) values at 10(-8) and 10(-10) M (-29 +/- 6%/-16 +/- 3% for PWM 0.125 microgram/ml and -17 +/- 9%/-11 +/- 9% for PWM 0.250 microgram/ml). This inhibitory effect could be abolished by an anti-TRH antiserum. There was no TRH effect on IgM and IgA activities, IFN-gamma activity and lymphocyte proliferation compared with the PWM stimulated values alone. The described TRH effect on the polyclonal IgG response by PBMC gives further evidence for a functional link between the immune system and the endocrine system, although its underlying mechanism is not yet clear.

Mitogen-activation of spleen cells in aged animals is potentiated by dietary restriction: a preliminary report

Dietary restriction has been reported to be associated with increased life span and increased DNA repair capacity in both male and female rats and mice. We examined dietary restriction effects on immune system function and prolongation of life span in specific pathogen free rats and mice. In this preliminary report the authors show that dietary restriction is correlated with a dramatic increase in the lifespan of both male and female rats and mice in a pathogen free environment, and in the capacity of cultured splenocytes from those animals to initiate blastogenesis in response to antigenic stimulation.

Evaluation of inter- and intramolecular primary structure homologies of interferons by a Monte Carlo method

Using Sellers TT algorithm, primary structure repeats have been described for interferon (IFN)-alpha, -beta 1, and gamma. To reevaluate these results and to extend them to IFN-beta 2 (interleukin-6), a modified algorithm was developed that uses a metric to define the "best" partial homology of two peptide sequences and to compare it to those detected in random permutations of the peptide. Using this approach, the known structural homologies of IFN-alpha with IFN-beta 1 and of human (Hu) IFN-gamma with murine (Mu) IFN-gamma were identified correctly. However, the primary structure repeats in the amino acid sequences of IFN-alpha, -beta 1, and -gamma turned out to be no better than those detectable in random permutations of these sequences. These results were confirmed using a different, nonlinear metric. A previously used approach to demonstrate significance was shown to produce false-positive results. No significant primary structure homologies were detected among IFN-beta 1, -beta 2, and -gamma. In contrast to the amino acid sequence analysis, the DNA sequence of HuIFN-beta 1 contained a significant repeat that had no significant counterpart in MuIFN-beta or in IFN-alpha. In conclusion, some previously reported results obtained with Sellers TT algorithm on amino acid sequences are easily explained as random similarities, and it is therefore strongly recommended that a method like ours should be used to control significance.