Melatonin shortens the survival rate of Ehrlich ascites-inoculated mice

OBJECTIVES Pineal gland may have a role in organism's protection against cancer. Melatonin as well as still unidentified low-weight molecular pineal substance(s) have been reported to have growth inhibitory effect on different tumor cells. We tested the influence of melatonin and of a bovine pineal extract on the survival rate of AKR mice inoculated with Ehrlich ascites. The tumor is known to have an accelerated development after pinealectomy.

MATERIAL AND METHODS

Male AKR mice, kept under a 14/10 hours - Light /Dark cycle, were inoculated intraperitoneally (i.p.) with 1.5x 10(6) Ehrlich ascites cells. On day three after inoculation the animals were divided in three groups (n=10). Each animal received i.p. daily (20.00H), until their death, 250 microl of solution containing melatonin (250 microg), pineal extract (equivalent of 1 bovine pineal gland) or saline.

RESULTS

The average survival rate of the animals treated with melatonin was shorter (14.8+/-2.23 days) compared to control animals (21.9+/-2.21 days)(p=0.01). The animals treated with the pineal extract had a longer survival rate (22.6 +/- 1.8 days) but not statistically significant. The pineal extract was not available for testing at higher doses.

CONCLUSION

In our model, melatonin had a deleterious effect on the survival rate raising the question whether it is correct to assume that the hormone shows lack of adverse reactions.

Creating a career ladder for nursing assistants in long-term care

This article describes the development, implementation, and evaluation of a career ladder for certified nursing assistants in long-term care. A career ladder is an effective way to maximize the use of unlicensed workers without changing the skill mix (eg, no loss of licensed nursing positions) and allow the licensed nurse more time to perform higher-level clinical tasks, such as assessments, patient education, and documentation. Implementation of an unlicensed worker career ladder also can improve nursing assistant retention.

Does a liquid supplement improve energy and protein consumption in nursing home residents?

One popular strategy to improve the acceptance and efficacy of oral liquid supplements in long-term care is dispensing them during the medication pass, although few studies support its effectiveness. This study evaluated the impact of a supplement medication pass program on energy and nutrient consumption and weight in nursing home residents. Findings indicate that residents maintained their prestudy weight and had a 29% decrease in supplement energy intake, a 19% increase in food energy intake, and a 17% decrease in net energy intake (supplement plus food). Supplement and food protein intake remained stable. Over longer periods, this reduced energy consumption could lead to weight loss, so routine monitoring and periodic evaluations of resident intake (both food and supplement) are recommended to ensure residents are receiving and consuming adequate amounts of daily energy and nutrients.

[Abdominal hemangiopericytomas]

We present two cases of hemangiopericytoma, which are analyzed according to medical literature, although only few cases have been reported. Clinical, imagistic and histological findings of these rare vascular tumors are discussed.

The MHC class I-related receptor, FcRn, plays an essential role in the maternofetal transfer of gamma-globulin in humans

The transfer of maternal gamma-globulin (IgG) provides the neonate with humoral immunity during early life. In humans, maternal IgG is transported across the placenta during the third trimester of pregnancy. The expression of the MHC class I-related receptor, FcRn, in the human placenta suggests that this Fc receptor might be involved in the delivery of maternal IgG, but direct evidence to support this is lacking. In the current study an ex vivo placental model has been used to analyze the maternofetal transfer of a recombinant, humanized (IgG1) antibody in which His435 has been mutated to alanine (H435A). In vitro binding studies using surface plasmon resonance indicate that the mutation ablates binding of the antibody to recombinant mouse and human FcRn. Relative to the wild-type antibody, the H435A mutant is deficient in transfer across the placenta. Significantly, the mutation does not affect binding to Fc gamma RIII, an FcR that has been suggested in earlier studies to mediate the transfer of maternal IgG. The analyses demonstrate that binding of an IgG to FcRn is a prerequisite for transport across the perfused placenta. FcRn therefore plays a central role in the maternofetal delivery of IgG and this has implications for the use of protein engineering to improve the properties of therapeutic antibodies.

Simian virus 40 detection in human mesothelioma: reliability and significance of the available molecular evidence

Simian virus 40 was discovered as a contaminant of early poliovirus vaccines that were inadvertently administered to millions of people in Europe and the United States between 1955 and 1963. Although SV40 was proven to be oncogenic in rodents and capable of transforming human and animal cells in vitro, its role in human cancer could not be proven epidemiologically. The matter was forgotten until 1993 when SV40 was accidentally found to cause mesotheliomas in hamsters injected intra-cardially. Subsequently, DNA sequences associated with its powerful oncogenic principal, the large T antigen, were found with high frequency in human pleural mesothelioma using the polymerase chain reaction (PCR). Since then many laboratories have confirmed the human findings. However, a few laboratories have failed to reproduce these data and the authors of the studies have claimed that the detection of SV40 DNA may simply represent PCR contamination artefacts. The controversy raised by this viewpoint is reviewed in this article together with a critical appraisal of the reliability of the molecular techniques used to detect SV40 DNA, in order to evaluate the potential aetiopathogenic role of SV40 in human mesothelioma.

Association of SV40 with human tumours

SV40 was discovered as a contaminant of poliovirus vaccines that were inadvertently administered to millions of people in Europe and the United States between 1955 and 1963. Shortly afterwards, SV40 was proven to be oncogenic in rodents and capable of transforming human and animal cells in vitro. The possibility that SV40 might cause tumours in humans thus became a subject of scientific and public interest and scrutiny. However, largely due to a lack of significant epidemiological evidence, interest in assessing SV40's potential carcinogenic role in humans diminished. Recently, many laboratories have reported the presence of SV40-like DNA in a high proportion of human mesotheliomas, ependymomas and osteosarcoma (the three main types of tumours caused by virus in hamsters), renewing the question whether SV40 might be a human tumour virus. Molecular data from these studies are reviewed to re-evaluate the potential role of SV40 as a human carcinogen.

[Acute abdomen and diabetic patients--difficulties of diagnosis and therapeutical decision]

We present a retrospective study based on 50 diabetic patients with acute abdominal diseases. Usually, clinical features were not typical, without defining signs of acute abdomen, despite frequent severe anatomo-pathological forms (6 of 12 acute appendicitis were gangrenous, with generalised or localised peritonitis; 15 of 22 acute colecystitis were gangrenous). In diabetic patients, with metabolic disorders and cetoacidosis, positive diagnosis and the decision of laparotomy are difficult problems, often delated, with a negative influence on the evolutions and prognosis of these patients.

Two models of restorative nursing care in the nursing home: designated versus integrated restorative nursing assistants

A 6-month clinical trial was conducted to evaluate two models of restorative nursing care designed to improve mobility in nursing home residents. The models were compared on number of residents enrolled, documentation of nursing assistant (NA) compliance, and nursing staff satisfaction. The designated model, which relied on one specially trained NA to perform restorative activities on the unit, resulted in higher rates of enrollment, compliance, and staff satisfaction compared with the integrated model, which relied on regular staff NAs who were trained to incorporate restorative activities into their daily routines.

Molecular requirements for T cell recognition by a major histocompatibility complex class II-restricted T cell receptor: the involvement of the fourth hypervariable loop of the Valpha domain

The role of two central residues (K68, E69) of the fourth hypervariable loop of the Valpha domain (HV4alpha) in antigen recognition by an MHC class II-restricted T cell receptor (TCR) has been analyzed. The TCR recognizes the NH2-terminal peptide of myelin basic protein (Ac1-11, acetylated at NH2 terminus) associated with the class II MHC molecule I-Au. Lysine 68 (K68) and glutamic acid 69 (E69) of HV4alpha have been mutated both individually and simultaneously to alanine (K68A, E69A). The responsiveness of transfectants bearing wild-type and mutated TCRs to Ac1-11-I-Au complexes has been analyzed in the presence and absence of expression of the coreceptor CD4. The data demonstrate that in the absence of CD4 expression, K68 plays a central role in antigen responsiveness. In contrast, the effect of mutating E69 to alanine is less marked. CD4 coexpression can partially compensate for the loss of activity of the K68A mutant transfectants, resulting in responses that, relative to those of the wild-type transfectants, are highly sensitive to anti-CD4 antibody blockade. The observations support models of T cell activation in which both the affinity of the TCR for cognate ligand and the involvement of coreceptors determine the outcome of the T cell-antigen-presenting cell interaction.

Functional expression of the MHC class I-related receptor, FcRn, in endothelial cells of mice

Our recent data indicate that the MHC class I-related receptor, FcRn, plays a role in regulating serum IgG levels, in addition to its known role in transferring IgG from mother to young. In the current study, the distribution of FcRn in adult mice has been investigated using several approaches. First, tissue distribution of anti-FcRn F(ab')2, murine IgG1 and recombinant, IgG1-derived Fc-hinge fragments has been analyzed, and these FcRn binding proteins localize predominantly in skin and muscle with lesser amounts in liver and adipose tissue. Second, histochemical analyses of muscle and liver with anti-FcRn F(ab')2 indicate that FcRn is expressed in the endothelium of small arterioles and capillaries, but not in larger vessels such as the central vein and portal vasculature. Third, immunoprecipitation and immunofluorescence studies of cultured murine endothelial cells show that functional FcRn is expressed in these cells, and is located within vesicular structures in the cytosol and not on the membrane. Taken together the data demonstrate that FcRn is expressed in functionally active form in endothelial cells, indicating that these cells are a possible site at which serum IgG homeostasis is maintained.

Increasing the serum persistence of an IgG fragment by random mutagenesis

The major histocompatibility complex (MHC) class I-related receptor FcRn is involved in regulating serum gammaglobulin (IgG) levels in mice. With the aim of increasing the serum half-life of a recombinant murine Fc gamma 1 fragment, the affinity for binding to FcRn at pH 6.0 has been increased by random mutagenesis of Thr252, Thr254, and Thr256 followed by selection using bacteriophage display. These residues were chosen as they are in proximity to the FcRn-IgG (Fc) interaction site. Two mutants with higher affinity (due to lower off-rates) than the wild-type Fc have been isolated and analyzed in pharmacokinetic studies in mice. The mutant with the highest affinity has a significantly longer serum half-life than the wild type fragment, despite its lower off-rate from FcRn at pH 7.4. The results provide support for the involvement of FcRn in the homeostasis of serum IgGs in mice. The indications that a homologous FcRn regulates IgG levels in humans suggest that this approach has implications for increasing the serum persistence of therapeutic antibodies.

Delineation of the amino acid residues involved in transcytosis and catabolism of mouse IgG1

The MHC class I-related receptor, FcRn, is involved in both the transcytosis of serum gamma-globulins (IgGs) and in regulating their serum persistence. The interaction site of FcRn on the Fc region of rodent IgG has been mapped to residues at the CH2-CH3 domain interface using site-directed mutagenesis and x-ray crystallographic analyses. In the current study, the role of individual residues (H310, H433, and N434) at this interface in mediating the Fc-FcRn interaction has been investigated using recombinant, mutated Fc hinge fragments derived from mouse IgG1. In addition, two highly conserved Fc histidines (H435 and H436) have been mutated to alanine, and the resulting mutated Fc hinge fragments were analyzed in both transcytosis and pharmacokinetic studies in mice and in competition binding assays using recombinant, soluble FcRn. The analyses indicate that mutation of H310, H435, and, to a lesser extent, H436 to alanine results in reduced activity of the Fc hinge fragments in both in vivo and in vitro assays. Thus, in addition to the previously defined role of 1253 in the FcRn-IgG interaction, these histidines play a key role in mediating the functions conducted by this Fc receptor. The effects of these mutations on binding of Fc hinge fragments to staphylococcal protein A have also been analyzed and demonstrate a partial, but not complete, overlap of the FcRn and staphylococcal protein A interaction sites on mouse IgG1.

Delineation of the amino acid residues involved in transcytosis and catabolism of mouse IgG1

The MHC class I-related receptor, FcRn, is involved in both the transcytosis of serum gamma-globulins (IgGs) and in regulating their serum persistence. The interaction site of FcRn on the Fc region of rodent IgG has been mapped to residues at the CH2-CH3 domain interface using site-directed mutagenesis and x-ray crystallographic analyses. In the current study, the role of individual residues (H310, H433, and N434) at this interface in mediating the Fc-FcRn interaction has been investigated using recombinant, mutated Fc hinge fragments derived from mouse IgG1. In addition, two highly conserved Fc histidines (H435 and H436) have been mutated to alanine, and the resulting mutated Fc hinge fragments were analyzed in both transcytosis and pharmacokinetic studies in mice and in competition binding assays using recombinant, soluble FcRn. The analyses indicate that mutation of H310, H435, and, to a lesser extent, H436 to alanine results in reduced activity of the Fc hinge fragments in both in vivo and in vitro assays. Thus, in addition to the previously defined role of 1253 in the FcRn-IgG interaction, these histidines play a key role in mediating the functions conducted by this Fc receptor. The effects of these mutations on binding of Fc hinge fragments to staphylococcal protein A have also been analyzed and demonstrate a partial, but not complete, overlap of the FcRn and staphylococcal protein A interaction sites on mouse IgG1.

Localization of the site of the IgG molecule that regulates maternofetal transmission in mice

Site-directed mutagenesis of a recombinant Fc hinge fragment has recently been used to localize the site of the mouse IgG1 (mIgG1) molecule that is involved in the intestinal transfer of recombinant Fc hinge fragments in neonatal mice. This site encompasses Ile-253, His-310, Gln-311, His-433 and Asn-434, localized at the CH2-CH3 domain interface and overlapping with the staphylococcal protein A-binding and catabolic sites. In the present study, the effect of these mutations on the maternofetal transfer of Fc hinge fragments has been studied. Experiments to analyze transfer of radiolabeled Fc hinge fragments from the circulation of 15-18 day pregnant mice to fetuses in utero demonstrate that the mutations affect the maternofetal transmission in a way that correlates closely with the effects of the mutations on intestinal transfer and catabolism. The studies indicate that the neonatal Fc receptor, FcRn, is involved in transcytosis across both yolk sac and neonatal intestine in addition to the regulation of IgG catabolism.

Different patterns of some systemic immunological cell markers in HIV only, and HIV/hepatitis C-infected children

In three groups of children, aged 4-6 years (i.e., human immunodeficiency virus [HIV]-negative controls, HIV-seropositive, and dually HIV/hepatitis C virus (HCV)-seropositive), two types of immunological investigations in blood cells were performed: (a) numerical assays, consisting of flow cytometric measurement of different lymphocyte sets or subsets, as follows: CD3+, CD19+, CD4+, CD16+/CD56+; (b) functional assays, consisting of interleukin-1 (IL-1) levels as well as natural killer (NK)-cell dependent cytotoxicity, in CD14+, or CD16+/CD56+ sorted cells, respectively. Results revealed, in addition to the classic markers (i.e., lower numbers of CD4+ cells and a decreased CD4+/CD8+ ratio in both infected groups of subjects) other findings, as follows: increased numbers of CD8+ cells in dually infected children, accompanied by a lower CD4+/CD8+ ratio, as compared to HIV-infected alone; diminished numbers of CD16+/CD56+ cells in both groups of infected patients were correlated with a lower NK-cell cytotoxicity rate; a reduced capacity for IL-1 synthesis of sorted macrophages both in HIV-only and in HIV/HCV-seropositive subjects, but significantly more marked in dually infected children. The importance of the present data in the immune monitoring of AIDS disease in a pediatric population is discussed.

[The synthesis of aldoxime ester derivatives with biological activity]

Continuing our investigations for obtaining etheric derivatives from the oximes of some carbonylic compounds, five carboxymethylic ethers of some aldoximes were synthetized. Their structure was confirmed by chemical and spectral analyses. The antimicrobial activity of the obtained products towards 6 microorganisms species was determined.

[Amphoteric ion intermediates in the pyrazine series. II. The action of p-nitrophenacyl bromide on pyrazine]

Continuing to present the results of the investigations carried out on the amphoteric ions intermediates of the N-heteroatomic system with 2 natrium atoms in positions 1, 4, new pyrasine derivatives synthetized with p-nitro-phenacyl bromide are described. The observations on their antimicrobial and antiyeast activities is discussed.

[The production and physicochemical characteristics of new pyridazinyl-3-methyl-4-phenylazo-5-pyrazolones]

The synthesis of eight new 1-(R-pyridazinil)-3-methyl-4-(R-phenylazo)-5-pyrazolone, the structure of which was confirmed by the results of the physicochemical analysis, is presented. The preliminary tests for determining their biological action have revealed a moderate antimicrobial activity.

[The direction and motivation for an evolution in methods of antiulcer surgery]

A 23-year retroactive analysis of a heterogeneous series of observations with unfavourable tardy results after antiulcer surgeries showed that the most failures requiring a second surgery appear after large resections with gastrojejunal or gastroduodenal anastomosis and after vagotomies associated with gastric drainage. The most favourable tardy results followed the vagotomy associated with limited gastric resection (hemigastrectomy). This kind of intervention prevents the appearance of the ulcerous relapses and lowers significantly the incidence of the other type of post-surgical iatrogenic complications. The optimal protection against the ulcerous relapse given by vagotomy associated with hemigastrectomy permits a tactical adaptation of the intervention to the lesional and physiopathological characteristics of each case.

[Synthesis and physicochemical and biological characteristics of phthalazine derivatives]

Further studies in view of obtaining new stable phtalasiniuilides present the synthesis and physico-chemical and biological characterization of certain derivatives obtained through the action of p-phenyl-phenacyl and p-nitro-phenacyl bromides upon R-phtalasine. The structure of the new products was confirmed by physicochemical and spectral analyses. The preliminary biological tests showed a moderate antimicrobial activity of certain studies compounds.

[Pyridazinilides (XIV). The action of p-phenyl-phenacyl bromide on 3-phenyl-pyridazine]

This time the synthesis of some new derivatives obtained by the quaternary substitution of one of the heterocyclic nitrogen atoms and by reactions of dipolar cycloaddition is presented. The results of the tests on their antimicrobial and antiinflammatory actions are discussed.