[Study on the reliability and validity of the Chinese Criteria of Health Scale for the elderly people]

Objective: To evaluate the reliability and validity of the Chinese Criteria of Health Scale for the elderly people. Methods: A cross-sectional study was performed among older adults of Meiyuan Community in Haidian District, Beijing and Nanwangkong Village in Qingzhou City,Shandong Province during July 2021. Using a cluster sampling method, totally 667 elderly people were investigated by face-to-face interview, using the scale which was formulated after two rounds of the Delphi method and pilot study. The overall scale includes physical health, mental health and social health subscales, including 9, 52 and 15 items, respectively. Four weeks after the survey, 56 elderly people were randomly selected and repeated the survey with the same method. The test-retest reliability, split-half reliability and internal consistency reliability of the scale were evaluated, and the validity was evaluated at the same time, including construct validity and content validity. Results: A total of 710 questionnaires were distributed and 667 valid questionnaires were obtained, with a total effective rate of 93.94%. The score of the overall scale was 79.79±16.22, the scores of the physical health, mental health, social health sub-scores were 41.64±9.76, 26.82±3.92 and 11.34±5.19, respectively. The scale had excellent reliability. In the test-retest reliability, the intraclass correlation coefficient (ICC) of the overall scale and each subscale were 0.766-0.861, and the weighted Kappa values were 0.762-0.817. The Spearman-Brown coefficient of the overall scale and each subscale in the split-half reliability were 0.722-0.855 (all P<0.001). The Cronbach's α coefficients of the overall scale of internal consistency reliability and each subscale were 0.748-0.899, and the Cronbach's α coefficients of each dimension were from 0.709 to 0.963(all P<0.001). At the same time, the scale had good construct validity and content validity. The correlation coefficients between the score of each dimension and its sub-scale were larger, from 0.641 to 0.873 (all P<0.05). The cumulative variance contribution rates of the scale and three subscales were all more than 50% of the approved standard. A total of 11 common factors were extracted, and all the load values of each item on the corresponding factors were ≥0.04. Conclusion: The Chinese Criteria of Health Scale for the elderly people has good validity and excellent reliability. It can be used as a basis for the scientific division of the health status of the elderly, the formulation of relevant policies by the government and the provision of appropriate health services for the elderly.

[The gender disparity and relevant factors of frailty in the elderly of communities in Beijing based on Fairlie decomposition analysis]

Objective: To analyze the gender disparity and relevant factors of frailty in the elderly of communities in Beijing. Methods: From November 2015 to January 2016, 1 557 participants aged 60 and older in four communities of Dongcheng district in Beijing were recruited by cluster sampling. The information of demographic characteristics, social support, economic status, health status, prevalence situation, cognitive function, emotion and comprehensive assessment of the elderly were collected by a self-made questionnaire. The frailty index (FI) model was used to evaluate the frailty of the elderly. Multivariate nonconditional logistic regression model and Fairlie decomposition method were applied to analyze the relevant factors and their contribution rate to the difference between males and females. Results: The age of subjects was (74.5±8.5) years old, ranging from 60-102 years old, among which 641 were males, accounting for 41.2%. The M (Q₁, Q₃) of FI was 0.09 (0.06, 0.14), among which the value in males was 0.08 (0.05, 0.13), lower than females [0.10 (0.06, 0.15)] (P<0.001).The frail proportion in female was 14.9% (137/916), higher than that of male [8.4% (54/641)] (P<0.001). Multivariate nonconditional logistic regression model analysis demonstrated that common relevant factors associated with frailty in older women and men include: age ≥80 years old, marital status as not married (unmarried, separated, divorced, or widowed), living alone increased the risk of frailty; participating in group activities ≥3 times/week and exercising regularly decreased the risk of frailty (all P<0.05). Fairlie decomposition method showed that the contribution rate of life style, family support, marital status and social support were 32.21%, 15.26%, 8.23% and 4.34%, respectively (all P<0.05). Conclusions: The frailty degree and frailty proportion of elderly women in communities in Beijing were higher than those of men of the same age. The frailty gender difference was related to lifestyle, family support, marital status and social support.

[Relationship between frailty status and risk of death in the elderly based on frailty index analysis]

Objective: To analyze the relationship between frailty status and the risk of death in the elderly based on the frailty index (FI). Methods: Data from a prospective cohort study conducted between 2005 and 2015 in elderly people of an urban community in Beijing were analyzed. The variables related to health and frailty status based on the 2005 baseline survey and death as outcome variables collected in 2015 were used. A FI model was used to evaluate the correlation between FI and mortality in the elderly people in different age groups was analyzed. Cox regression was applied to evaluate the influence of FI on the risk of death, and Kaplan-Meier curves was used to show the survival rate of different frailty levels in the elderly adults. Results: Of the 1 301 elderly people included in the analysis, 403 died during 2005-2015, with the 10-year mortality rate of 31.0%(403/1 301). The mortality rate of the elderly increased with the increase of FI, but, with the increase of FI value, the rate of mortality increased slowly. The limit value of FI causing death was around 0.70, indicating any new health problem might cause death at this value. Cox regression analysis showed that higher FI was associated with higher risk for death (HR=1.143, 95%CI: 1.034-1.248, P=0.000), and FI was more significantly associated with death than age (HR=1.143 vs. HR=1.048, t=5.827, P=0.000). With the increase of age, the effect of frailty on the risk of death decreased (HR=1.179 to HR=1.120). Kaplan-Meier curves showed that the survival rate of the elderly in all age groups decreased with the increase of frailty (Log-rank=317.812, 354.203, 247.258, all P=0.000). The survival time between different frailty levels in the elderly were significantly different, except for the elderly adults aged ≥80 years with severe frailty level (0.4≤FI<0.5, FI≥0.5, P=0.368). Conclusions: Compared with other evaluation tools of frailty, FI model can better reflect the frailty status of the elderly in communities in Beijing and has a high sensitivity in predicting adverse outcomes such as mortality. In the intervention of frailty in the elderly, focusing on relatively young elderly might be more effective in reducing the adverse outcomes caused by frailty.

Transcriptomic study on persistence and survival of Listeria monocytogenes following lethal treatment with nisin

OBJECTIVES

The aim of this study was to determine gene expression associated with the persistence of a Listeria monocytogenes stationary-phase population when facing lethal nisin treatment.

METHODS

RNA-Seq analysis was used for gene expression profiling of persister cells in nutrient-rich medium (persister TN) compared with untreated cells (non-persister). The results were confirmed using reverse transcription quantitative PCR (RT-qPCR).

RESULTS

Functional genes associated with the persister population were identified in multiple systems, such as heat-shock-related stress response, cell wall synthesis, ATP-binding cassette (ABC) transport system, phosphotransferase system (PTS) and SOS/DNA repair.

CONCLUSIONS

This study pointed to genetic regulation of persister cells exposed to lethal nisin concentrations and provides some insight into possible mechanisms of impeding bacterial persistence.

[Relationship between fall and frailty index in elderly adults of urban community in Beijing]

Objective: To evaluate the frailty status and understand the relationship between the incidence of fall and frailty status in the elderly in Beijing. Methods: A cross-sectional study was conducted in old people aged ≥60 years in Longtan community of Dongcheng district in Beijing from November 2015 to January 2016. The information about any fall during the past year and frailty status of the elderly were collected with a standardized structured questionnaire in face-to-face interviews. The frailty status of elderly people was assessed with frailty index (FI) method. Logistic regression analysis was used to explore the relationship between fall and frailty status among the elderly. Results: Among 1 557 old people surveyed, the incidence of fall was 17.8% (277/1 557) during the past year. The incidence of fall in women (21.0%, 192/277) was statistically higher than that in men (13.3%, 85/277) (χ(2)=15.288, P=0.000). The median (quartile) value of FI of the elderly surveyed was 0.09 (0.08); and women had a higher FI median value than men [0.10 (0.08) versus 0.08 (0.07)](Z=5.376, P=0.000). The median FI value (quartile range) of 277 old people with history of fall in previous year was 0.12 (0.11), which was higher than the median FI value of 0.08 (0.07) of 1 280 old people without fall history (Z=7.501, P=0.000). Logistic regression analysis showed that higher FI value was associated with more risks for fall; and FI value showed the greatest impact on the incidence and frequency of fall (OR=1.093, 2.234) compared with other related factors of fall, such as age and gender. Conclusion: Frailty status has a greater impact on both incidence and frequency of fall compared with other factors in elderly people in Beijing; more attention should be paid to weak and old adults in the prevention of fall.

[Application of frailty index for comprehensive geriatric assessment in the elderly in China]

OBJECTIVE

To discuss the suitability of frailty index for comprehensive geriatric assessment(FI-CGA)in the elderly in China, and evaluate the application of FI-CGA in China.

METHODS

A comprehensive geriatric assessment was conducted among 118 old adults receiving health examination, and frailty index was calculated. Clinical frailty scale(CFS)was also used to evaluate the frail status of the old adults. The correlation between FI-CGA value and CFS level of the old adults was analyzed.

RESULTS

The mean value of FI-CGA was 0.19 ± 0.07, and the average level of CFS was 3.11 ± 1.46. Women had higher mean value of FI-CGA and higher CFS level than men(FI-CGA= 0.20 ± 0.02 for women, 0.19 ± 0.07 for men; CFS =3.40 ± 0.55 for women, 3.10 ± 1.48 for men), but the differences had no significance(t=0.270, 0.452, P=0.788, 0.652). The FI-CGA value and CFS level increased with age(F=10.437, 5.651, P=0.000, 0.001); and there was a positive correlation between FI-CGA value and CFS level(r=0.615, P=0.000).

CONCLUSION

FI-CGA is an effective model for the quantitative evaluation of the frail status of the elderly, and can be used in the clinical practice of geriatric medicine.

Smart Sensing System for the Prognostic Monitoring of Bone Health

The objective of this paper is to report a novel non-invasive, real-time, and label-free smart assay technique for the prognostic detection of bone loss by electrochemical impedance spectroscopy (EIS). The proposed system incorporated an antibody-antigen-based sensor functionalization to induce selectivity for the C-terminal telopeptide type one collagen (CTx-I) molecules—a bone loss biomarker. Streptavidin agarose was immobilized on the sensing area of a silicon substrate-based planar sensor, patterned with gold interdigital electrodes, to capture the antibody-antigen complex. Calibration experiments were conducted with various known CTx-I concentrations in a buffer solution to obtain a reference curve that was used to quantify the concentration of an analyte in the unknown serum samples. Multivariate chemometric analyses were done to determine the performance viability of the developed system. The analyses suggested that a frequency of 710 Hz is the most discriminating regarding the system sensitivity. A detection limit of 0.147 ng/mL was achieved for the proposed sensor and the corresponding reference curve was linear in the range of 0.147 ng/mL to 2.669 ng/mL. Two sheep blood samples were tested by the developed technique and the results were validated using enzyme-linked immunosorbent assay (ELISA). The results from the proposed technique match those from the ELISA.

Rapid and molecular selective electrochemical sensing of phthalates in aqueous solution

Reported research work presents real time non-invasive detection of phthalates in spiked aqueous samples by employing electrochemical impedance spectroscopy (EIS) technique incorporating a novel interdigital capacitive sensor with multiple sensing thin film gold micro-electrodes fabricated on native silicon dioxide layer grown on semiconducting single crystal silicon wafer. The sensing surface was functionalized by a self-assembled monolayer of 3-aminopropyltrietoxysilane (APTES) with embedded molecular imprinted polymer (MIP) to introduce selectivity for the di(2-ethylhexyl) phthalate (DEHP) molecule. Various concentrations (1-100 ppm) of DEHP in deionized MilliQ water were tested using the functionalized sensing surface to capture the analyte. Frequency response analyzer (FRA) algorithm was used to obtain impedance spectra so as to determine sample conductance and capacitance for evaluation of phthalate concentration in the sample solution. Spectrum analysis algorithm interpreted the experimentally obtained impedance spectra by applying complex nonlinear least square (CNLS) curve fitting in order to obtain electrochemical equivalent circuit and corresponding circuit parameters describing the kinetics of the electrochemical cell. Principal component analysis was applied to deduce the effects of surface immobilized molecular imprinted polymer layer on the evaluated circuit parameters and its electrical response. The results obtained by the testing system were validated using commercially available high performance liquid chromatography diode array detector system.

Solid-substrate fermentation ofKloeckera apiculata andCandida utilis on apple pomace to produce an improved stock-feed

Apple pomace was used in solid-substrate fermentation with the yeastsKloeckera apiculata orCandida utilis Y15. A total crude protein content of 7.5% (w/w) was achieved after 72 h for each yeast. The concentration of essential amino acids in the modified apple pomace was more than twice that in the control, enhancing its nutritive value as a stock-feed supplement. The fermentation of pomace as described can be used to reprocess this waste material into a useful value-added product for the agricultural sector.

Antimicrobial and immunomodulatory activities of an ovine proline/arginine-rich cathelicidin

In in vitro co-culture experiments, the ovine-derived cathelicidin OaBac5mini showed antimicrobial activity against Escherichia coli cells and modulated production of a cytokine by a mammalian inflammatory cell type (macrophage). Using atomic force microscopy, the morphology of peptide-treated E. coli bacteria showed no cell lysis, indicating an intracellular mode of action of the peptide leading to bacterial cell inhibition. At a concentration of 50microg/mL OaBac5mini, the peptide suppressed production of the inflammatory cytokine interleukin-12 by murine J774A cells that had been stimulated with Staphylococcus aureus strain Cowan; levels of other cytokines were unaffected. Thus, certain cationic peptides can enter and disrupt invading Gram-negative pathogens and may be able to modulate inflammatory responses induced by Gram-positive bacterial products.

Enterocins in food preservation

The Enterococcus genus, a member of the Lactic Acid Bacteria (LAB) is found in various environments, but more particularly in the intestines of humans and other animals. Although sometimes associated with pathogenicity these bacteria have many benefits. They have been found in traditional artisanal fermented products, are used as probiotic cultures and nowadays extensively studied for the production of bacteriocins--the enterocins. Many of these enterocins have been found to be active against Listeria monocytogenes, and a few have also been reported to be active even against Gram negative bacteria, an unusual property for the bacteriocins produced by LAB. These properties have resulted in many studies describing the use of enterocins as preservatives in foods of animal and vegetable origin. This review covers the most recent information on the use of enterocins as food preservatives, either produced in-situ by the addition of enterocin producing strains or as external preservatives in the form of purified or semi-purified extracts, to prevent the growth of spoilage and pathogenic microorganisms.

Antimicrobial peptides isolated from the blood of farm animals

The development of antimicrobial resistance by pathogenic bacteria has fuelled the search for alternatives to conventional antibiotics. Endogenous antimicrobial peptides have the potential to be used as new antimicrobial substances because they have low minimum inhibitory concentration in vitro, have broad-spectrum activity, neutralise lipopolysaccharides, promote wound healing and have synergistic effects with conventional antibiotics. Farm animals, in particular the blood that is a by-product of the meat and poultry industries, are an abundant, and currently underutilised, source of such antimicrobial peptides. These antimicrobial peptides could be isolated and developed into high-value products such as biopreservatives, topical neutraceutical products and pharmaceuticals. There have been some clinical trials of antimicrobial peptides as pharmaceutical products, but up to now, the trials have shown disappointing results. Further research and development is still needed before such peptides can be commercialised and full advantage taken of this waste product of the meat and poultry industries.

Antimicrobial fragments of the pro-region of cathelicidins and other immune peptides

In addition to the numerous cathelicidin peptides that are associated with the antimicrobial activity exhibited by a crude extract from ovine blood, a further three peptides with antimicrobial activity have been identified. These were part of the precursor cathelin domain of cathelicidins, a large fragment of platelet factor 4 and a small peptide similar to signal peptide of the T-cell glycoprotein CD4 precursor. Fragments of proteins that are involved in protecting the host from infection may have a secondary purpose as antimicrobial agents once they have carried out their primary purpose and are cleaved the main protein.

Effects of Cations on Antimicrobial Activity of Ostricacins-1 and 2 on E. coli O157:H7 and S. aureus 1056MRSA

Ostricacin-1 and ostricacin-2 (Osp-1 and Osp-2) were beta-defensins antimicrobial peptides that were purified from ostrich leukocytes using a cation-exchange column and a semi-prep RP-HPLC column. Both ostricacins were subjected to increased concentrations of monovalent cations (K(+) and Na(+)) and divalent cations (Ca(2+) and Mg(2+)) in order to investigate the effect of cations on the activity of these ostricacins on Gram-negative bacteria and Gram-positive bacteria. The radial diffusion assay method showed that both ostricacins were sensitive to the presence of cations. The divalent cations showed more antagonized effect on the activity against Gram-negative bacteria than the monovalent cations, as the ostricacins lost ability to inhibit bacterial growth at very low concentration (5 mM). When viewed in the context of other defensins activity, our data support a hypothesis that defensins' overall net positive charge determine the sensitivity to cations.

Mechanisms of action of ostrich beta-defensins against Escherichia coli

To understand their mechanism of antimicrobial activity against Gram-negative bacteria, ostrich beta-defensins, ostricacins-1 and 2 (Osp-1 and Osp-2), were compared with those of sheep myeloid antimicrobial peptide (SMAP)-29 and human neutrophil peptide (HNP)-1, well-characterized sheep alpha-helical and human alpha-defensin peptides, respectively. Fluorescence-based biochemical assays demonstrated that the ostricacins bound lipopolysaccharides and disrupted both outer and cytoplasmic membrane integrity. The ostricacins' permeabilizing ability was weaker than that of SMAP-29, but stronger than HNP-1. As ostricacins have previously shown the ability to inhibit bacterial growth, these peptides were suggested to be bacteriostatic to Gram-negative bacteria, which are caused by the interaction between the peptides and cytoplasmic targets causing the inhibition of DNA, RNA, and protein synthesis as well as enzymatic activities. These findings indicated promising possibilities for the peptides to be used in the development of therapeutic and topical products.

Identification of three novel ostricacins: an update on the phylogenetic perspective of β-defensins

Three new beta-defensins, ostricacins-2, 3 and 4 (Osp-2, 3 and 4), have been successfully purified and characterised from ostrich heterophils in addition to ostricacin-1 (Osp-1). These peptides are composed of 36-42 amino acids with a molecular weight range of 4.70-4.98 kDa. In vitro, Osp-1, 3 and 4 were active against Escherichia coli O157:H7 and Staphylococcus aureus 1056 MRSA, whilst Osp-2 was active against bacterial strains plus the yeast Candida albicans 3153A. Minimal inhibitory concentrations of the three ostricacins ranged from 0.96 microg/mL to 12.03 microg/mL. Comparison with the known beta-defensins from mammalian and other avian species revealed that the four ostricacins shared eight conserved residues (six cysteines and two glycines), identified as the 'beta-defensin core motif'. Comparisons of the sequence also indicated that beta-defensins could have originated from a common beta-defensin-like ancestor that occurred before avian and mammalian lines diverged.

Isolation and characterisation of antimicrobial peptides from deer neutrophils

The New Zealand deer industry is the largest and most advanced in the world. Antimicrobial peptides have been isolated from a wide range of organisms, but as yet there have been no reports on any from deer. This work investigates the antimicrobial activity and characterisation of peptides isolated from Cervus elaphus blood. It was found that deer blood contains proline/arginine-rich cathelicidins, similar to Bac5 peptides isolated from cattle, sheep and goats. A beta-defensin was also isolated that had a conserved amino acid sequence and mass similar to bovine neutrophil beta-defensins. The cathelicidin displayed strong activity against Gram-negative bacteria, but lesser activity against Gram-positive bacteria and yeast, whilst the beta-defensin showed good activity against all three test organisms.

Factors affecting the antimicrobial activity of ovine-derived cathelicidins against E. coli 0157:H7

Antimicrobial peptides extracted from ovine neutrophils have potential to be high-value by-products of the lamb industry as, for example, a biopreservative for chilled lamb products. This work was carried out to determine the conditions in which ovine peptides are most effective and to assist in product development. The activities of three synthetic ovine-derived antimicrobial peptides tested were not significantly affected by pH or temperature. However, they exhibited decreased activity at high ionic strengths and in the presence of divalent cations. The three peptides worked better in combination than individually.

Investigation of morphological changes to Staphylococcus aureus induced by ovine-derived antimicrobial peptides using TEM and AFM

The effect of two ovine-derived peptides on the morphology of Staphylococcus aureus NCTC 4163 cells were investigated using transmission electron microscopy and atomic force microscopy. Both techniques showed that SMAP29, an alpha-helical peptide, induced cell lysis, whereas OaBac5mini, a proline/arginine-rich peptide, caused no observable morphological changes. This is consistent with previous experimental work which indicated that SMAP29 caused cell death and induced cell lysis, whereas OaBac5mini acted by interacting with the inner cellular contents.

The role of isocitrate lyase and the glyoxylate cycle in Escherichia coli growing under glucose limitation

Escherichia coli changes its metabolism in response to environmental circumstances, and metabolic adaptations are evident in hungry bacteria growing slowly in glucose-limited chemostats. The role of isocitrate lyase (AceA) was examined in E. coli growing under glucose limitation. AceA activity was elevated in a strain-dependent manner in the commonly used E. coli K-12 laboratory strains MG1655 and MC4100, but an aceA disruption surprisingly increased fitness under glucose limitation in both strains. However, in bacteria adapted to limiting glucose in long-term chemostats, mutations outside aceA changed its role from a negative to a positive influence. These results suggest that a recently proposed pathway of central metabolism involving the glyoxylate cycle enzymes is redundant in wild-type bacteria, but may take on a beneficial role after context adaptation. Interestingly, the aceA gene sequence did not alter during prolonged selection, so mutations in unidentified genes changed the metabolic context of unaltered AceA from a negative to a positive influence in bacteria highly adapted to limiting glucose.

Avian antimicrobial peptides: the defense role of β-defensins

Avian antimicrobial peptides, classified as beta-defensins, have been identified from bloods of chicken, turkey, and ostrich; epithelial cells of chicken and turkey; and king penguin stomach contents. Beta-defensins are a family of antimicrobial peptides characterized by six cysteine residues forming beta-defensin motifs that are also found in bovine, ovine, pig, and human. These peptides are active against a wide range of microorganisms including Gram-positive and Gram-negative bacteria, fungi, and yeast. Analysis of evolutionary relationships of vertebrate beta-defensins showed that there might be a common ancestral gene between avian and other mammalian peptides. This ancient gene may have been passed down and evolved from species older than the oldest living birds, forming a beta-defensin-like precursor molecule. This review describes potential applications of these peptides in health care products.

Isolation and characterisation of proline/arginine-rich cathelicidin peptides from ovine neutrophils

Cathelicidins are a family of gene-encoded antimicrobial peptides found in mammals. Seven cathelicidin genes have been identified in sheep, but up to now only two variants of one of these predicted peptides (OaBac5) have been purified from ovine neutrophils. In this work numerous proline/arginine-rich cathelicidin peptides were purified, including the originally predicted OaBac5 and another OaBac5 variant. As well as this, the C-terminus of the predicted OaBac7.5 and various truncated forms of OaBac11 were purified. Even though these peptides were much smaller than those predicted, they still displayed antimicrobial activity.

Antimicrobial activity and bacterial-membrane interaction of ovine-derived cathelicidins

Three ovine-derived cathelicidins, SMAP29, OaBac5mini, and OaBac7.5mini, were compared with respect to their antibacterial activities and interactions with membranes. SMAP29 was confirmed to be alpha-helical, broad spectrum, and able to disrupt both the outer and the cytoplasmic membranes at relatively low concentrations. In contrast, the two proline- and arginine-rich OaBac peptides had more-modest antibacterial activities, reduced levels of lipopolysaccharide binding, and a lesser ability to depolarize the cytoplasmic membrane, consistent with a cytoplasmic target.

Ovine antimicrobial peptides: new products from an age-old industry

Antimicrobial peptides are part of the natural immune system of all plants and animals. This review focusses on ovine antimicrobial peptides because of the importance of the lamb industry in Australasia. The epithelial tissue β-defensins, respiratory surfactant-associated anionic peptides (SAAPs), and neutrophil cathelicidins are all described, and possible applications for these peptides are looked at, including use in ovine medicine, as biopreservatives, and as human therapeutics.

A device for feline head positioning and stabilization during magnetic resonance imaging

Minimization of head movement and reproduction of standard head positions are essential for reliable brain functional magnetic resonance imaging. Devices for stabilization and alignment of feline preparations are not available currently. We describe a system that involves minimal surgery, allows for both acute and chronic atraumatic positioning, and has the potential to be used for unanesthetized animals. The device uses non-metallic materials and stabilizes the head by means of an apparatus that fixes the head with nylon screws and dental cement in the frontal sinuses. Application of the head-stabilizing device decreases head movements by more than a factor of ten. Anatomical images show that this device provides 3 dimensional head placement at a precision comparable to that of a stereotactic frame, i.e. within 1 mm.

Mechanisms in regulating the release of serotonin from the perfused rat stomach

The mechanisms regulating the release of serotonin into the portal circulation as well as into the gastric lumen were studied in the isolated vascularly and luminally perfused rat stomach. Immunohistochemical study of the rat stomach showed that serotonin-containing enterochromaffin (EC) cells were densely packed in the antral mucosa, sparsely scattered in the corpus, and not found in the fundus. Such morphological findings suggest that serotonin detected in this study may have originated from antral EC cells. Luminal acidification stimulated the vascular release of serotonin but did not affect the luminal release of serotonin. The basal release of serotonin into the vasculature was 10 times higher than that into the gastric lumen at intragastric pH 2. The vascular release of serotonin is regulated by stimulation from cholinergic nicotinic mechanisms, whereas inhibitory neurotransmitters such as vasoactive intestinal peptide and NO are probably not involved. Somatostatin and peptide YY originating from endocrine cells may exert direct inhibitory effects, possibly via somatostatin and peptide YY receptors on the EC cells, and a cholinergic muscarinic mechanism may exert indirect effects on the vascular release of serotonin via the muscarinic receptor on the endocrine cells.

Fluid therapy of acute brain edema in children

The clinical experience with a new fluid therapy in children with acute brain edema complicated by infectious disease is reported. The clinical data of a retrospective group of 192 patients and a prospective study of 1,302 and 2,279 patients is summarized. One method of fluid therapy for children with acute brain edema is traditional; fluid intake is restricted to less than 1,200 mL/m(2) daily (60 mL/kg daily). Another method is the new fluid therapy regimen used in our prospective study, in which dehydration and fluid replenishment are individualized. On the first day the fluid intake of patients who survived varied from 40 to 208 mL/kg daily. The mortality rate in the two prospective groups was 19.66% in 1,302 patients and 17.2% in 2,279 patients, significantly lower than the 63.5% in the retrospective group (192 patients) (P <0.001). This result indicates that a wide range of fluid intake for children with acute brain edema is allowable during the first days of treatment. The appropriate dehydration and fluid replenishment should be individualized based on close observation of the patient's condition.

Immunohistochemical localization of tryptophan hydroxylase in the human and rat gastrointestinal tracts

Because few previous studies have shown the immunohistochemical localization of tryptophan 5-hydroxylase (TPH) in the gastrointestinal tract, we developed a specific antibody against TPH purified from mouse mastocytoma P-815 and stained human and rat gastrointestinal tracts. The specificity of the antibody was examined by Western blotting and by immunohistochemistry in brain sections. Human ileum and colon specimens, rat stomach, duodenum, jejunum, ileum and colon specimens, with and without colchicine treatment were prepared for immunohistochemistry. Immunoelectron microscopic double staining of TPH and serotonin/chromogranin A and immunofluorescence double staining of TPH and serotonin were performed to identify the cell types. Epithelial enterochromaffin (EC) cells, mast cells in the lamina propria and submucosa, and varicose fibers in the submucosa and muscle layer showed positive immunoreactivity in all segments examined from human and normal rat specimens. In colchicine-treated rat specimens, nerve cell bodies in the myenteric plexus were stained. Because the antibody does not cross react with tyrosine hydroxylase as defined in Western blotting or brain sections, these positive structures may contain TPH. The present results show evidence that EC cells, mast cells, and nerve cell bodies and fibers in the gastrointestinal tracts of both the human and the rat contain TPH and therefore may have the ability to synthesize serotonin from tryptophan.

[Multifactor analysis on proliferative retinopathy in elderly patients with type II diabetes]

To evaluate the importance of different risk factors and their mutual interactions in the occurrence of proliferative diabetic retinopathy (PDR) in the elderly patients with type II diabetes, an investigation was carried out on the relationship between PDR and various risk factors in 98 elderly cases of type II diabetes by way of stepwise regression analysis method. Results showed: (1) the average course of PDR was longer than that of diabetic patients without diabetic retinopathy (P < 0.01). Patients with PDR had higher values of BUN (P < 0.01), Cr(P < 0.05), GHbA1c(P < 0.01) and TC(P < 0.01) than those without retinopathy. Patients with PDR had higher coincidences of hypertension, coronary artery disease, proteinuria and urine microalbumin than those without retionpathy (P < 0.01) respectively, (2) multifactor analysis showed that BUN was one of the most important variables positively correlated with PDR, second to it in orders were the course of diabetes militus, GHbA1c, hypertention, proteinuria and urine microalbumin and TC.

CONCLUSION

To prevent the occurrence and progress of PDR in the elderly patients with type II diabetes, it is important not only to control blood sugar, but to control blood pressure and relieve renal damage.

Regression estimator in ranked set sampling

Ranked set sampling (RSS) utilizes inexpensive auxiliary information about the ranking of the units in a sample to provide a more precise estimator of the population mean of the variable of interest Y, which is either difficult or expensive to measure. However, the ranking may not be perfect in most situations. In this paper, we assume that the ranking is done on the basis of a concomitant variable X. Regression-type RSS estimators of the population mean of Y will be proposed by utilizing this concomitant variable X in both the ranking process of the units and the estimation process when the population mean of X is known. When X has unknown mean, double sampling will be used to obtain an estimate for the population mean of X. It is found that when X and Y jointly follow a bivariate normal distribution, our proposed RSS regression estimator is more efficient than RSS and simple random sampling (SRS) naive estimators unless the correlation between X and Y is low (/rho/ < 0.4). Moreover, it is always superior to the regression estimator under SRS for all rho. When normality does not hold, this approach could still perform reasonably well as long as the shape of the distribution of the concomitant variable X is only slightly departed from symmetry. For heavily skewed distributions, a remedial measure will be suggested. An example of estimating the mean plutonium concentration in surface soil on the Nevada Test Site, Nevada, U.S.A., will be considered.

Functional expression of the dihydrofolate reductase domain of Leishmania major dihydrofolate reductase-thymidylate synthase bifunctional protein

The dihydrofolate reductase (DHFR) domain of the bifunctional dihydrofolate reductase-thymidylate synthase from Leishmania major has been subcloned and expressed as a soluble protein in Escherichia coli strain PA414 harboring plasmid pLMDHFR. Homogeneous L. major DHFR was obtained by chromatography on methotrexate-Sepharose followed by DE52. The purified enzyme migrated as a single 25-kDa protein on SDS-PAGE. The native molecular weight was determined to be 26 kDa, indicating that the isolated domain is a monomer. N-terminal sequence analysis revealed that serine, the second amino acid in the coding sequence, was the N-terminal amino acid of the protein. The enzyme showed a pH optimum similar to that of the bifunctional protein. For purified DHFR, the Km values were <1.0 microM for H2folate and <1.0 microM for NADPH. The kcat of the most active DHFR preparation was 5 s-1. The Km and kcat values were similar to those of the bifunctional enzyme.

Effect of nimodipine on infectious brain edema in rabbits

AIM

To study the effect of nimodipine (Nim) on infectious brain edema (BE).

METHODS

An infectious BE model was induced by injection of Bordetella pertussis suspension (BPS) into right internal carotid artery in rabbits. Eighteen rabbits were randomly divided into 3 groups (n = 6). Group BE: BPS (0.6 mL.kg-1) was given; group NS: normal saline was given as control; group Nim: 10 min after injection of BPS, Nim, 10 micrograms.kg-1, was injected i.v. as a bolus followed by continuous infusion of 0.75 microgram.kg-1.min-1. All the rabbits were kept under observation for 4 h. Evans blue staining was assessed; water, calcium, calmodulin (Cal), and sodium contents were determined in the right brain.

RESULTS

Nim vs BE: water 82.2 +/- 1.0% vs 84.4 +/- 1.2 (P < 0.01); calcium 10.5 +/- 1.3 mmol.kg-1 dry tissue vs 17.5 +/- 1.4 (P < 0.01); Cal 15.9 +/- 1.8 mumol.kg-1 wet tissue vs 24.0 +/- 3.0 (P < 0.01); sodium 173 +/- 7 mmol.kg-1 dry tissue vs 275 +/- 38 (P < 0.05). No significant difference for Evans blue staining between the two groups.

CONCLUSION

Nim had beneficial effect on the infectious BE.

Trypanosoma brucei dihydrofolate reductase-thymidylate synthase: gene isolation and expression and characterization of the enzyme

The gene encoding the bifunctional dihydrofolate reductase (DHFR) and thymidylate synthase (TS) of Trypanosoma brucei brucei has been isolated and expressed in Escherichia coli, and the enzyme has been purified and characterized. The coding sequence of the DHFR-TS is 1581 nt, encoding a 527-amino-acid protein of 58,505 Da. The gene was expressed under control of the trc promoter in pKK233-2. The resulting expression plasmid conferred trimethoprim resistance to E. coli DH5 alpha and complemented the TS deficiency in chi 2913recA cells indicating the presence of active DHFR and TS. DHFR-TS was purified by methotrexate-Sepharose chromatography. In addition to the full-length enzyme, the purified enzyme contained 31 and 31.5-kDa forms of the enzyme that cross-reacted with anti-L. major DHFR-TS antibodies; one was truncated at the N- and C termini, and the other at only the C terminus. Despite the presence of sufficient TS for complementation, TS activity was not detectable in the crude extract or in the final purified enzyme preparation. Although the majority of the enzyme appears to be full length, it is possible that the TS domain has been degraded by one of more residues, which would inactivate the ability to synthesize thymidylate. Kinetic analysis of DHFR yielded kcat and Km values similar to those of related enzymes. The T. brucei DHFR has Ki values for antimicrobial antifolates pyrimethamine and trimethoprim which are significantly lower than the closely related T. cruzi or L. major DHFRs or than human DHFR.

[Effect of tetramethylhyrazine on proliferation of human fetal mesangial cells]

Tetramethylhyrazine (TMP) 0.6 and 1.2 mmol were added to human fetal mesangial cell (MC) cultures for 6 days, and the amounts of MC (cells/ml) were 37580 +/- 3475 and 27350 +/- 3418 respectively, significantly lower than that 71850 +/- 5108 in control (P < 0.05). The 3H-TdR incorporation by the MC with corresponding TMP were 1017 +/- 201 and 583 +/- 271, also significantly lower, than that 3575 +/- 306 in control (P < 0.01). After adding the TMP (1 mmol) to the cultures, the IL-6 bioactivity were 2118 +/- 215 that were markedly lower than those in controls (4128 +/- 351, P < 0.01). It revealed that the TMP inhibited the growth of MC and the mechanism of its inhibition might be due to that TMP could reduce the IL-6.

Synthetic and oxidative studies on 8-(arylamino)-2'-deoxyguanosine and -guanosine derivatives

Facile aerial oxidation is a general feature of guanine ribo- and 2'-deoxyribonucleosides that are substituted at the 8-position by an aminoaryl group. In previous work, it had been suggested that two of the major oxidation products are a pair of diastereomers having a spiro structure. These were presumed to be related by a chiral difference at the spiro carbon atom. The pattern of the oxidative process involves a contraction of the pyrimidine ring. It was thought to be analogous to that suggested by other investigators for the oxidation of uric acid, but for which no really definitive evidence had been presented. We have been able now to isolate in a crystalline state one of the diastereomers produced by the aerial oxidation of 8-phenylaminoguanosine under alkaline conditions. Analysis by X-ray diffraction has now confirmed the type of spiro structure promulgated previously. These findings also imply that spiro compounds are likely to be produced during the aerial oxidation of any 8-arylaminoguanine nucleoside or 2'-deoxynucleoside. In addition, this work adds considerable weight to the results of Poje and Sokolic-Maravic who proposed that a spiro intermediate is produced during the aerial oxidation of uric acid (12,13). However, they found this compound to be unstable to base, in contrast to the arylaminoguanine oxidation products. In the course of the above work we showed that the 8-arylamino derivatives of guanosine can be converted by the Barton deoxygenation method to the corresponding 2'-deoxyribonucleosides. This makes available a number of the latter compounds, which are not easily prepared by other methods.

Expression, purification, and characterization of thymidylate synthase from Lactococcus lactis

The thymidylate synthase (TS) gene from Lactococcus lactis has been highly expressed in Escherichia coli. The TS protein was purified by sequential chromatography on Q-Sepharose and phenyl-Sepharose. Six grams of cell pellet yielded 140 mg of homogeneous TS. TS is a highly conserved enzyme, and several of the conserved amino acid residues that have been implicated in catalytic function are altered in L. lactis TS. By use of a 3-dimensional homology model, we have predicted covariant changes that might compensate for these differences. With the large amounts of L. lactis TS now available, studies can be pursued to understand the structure-function relationships of this enzyme compared to other TSs and to confirm the presumed roles of the compensatory changes predicted in the homology model.

[Histological and immunohistochemical study and AgNOR analysis of smooth muscle tumors of the digestive tract]

Smooth muscle tumors of the esophagus (n = 29), stomach (n = 30), small intestine (n = 31) and large intestine (n = 12) were examined histologically and immunohistochemically for vimentin (Vim), desmin (Des), S100, fibronectin (FN) and cytokeratin (Cyt) and for nucleolar organizer regions (AgNOR). There were 49 cases of leiomyoma (LM), 51 cases of leiomyosarcoma (LS) and 2 cases of leiomyoblastoma(LB). Histologically, LS was characterized by cellular atypia, more cells in mitosis and invasion to adjacent normal tissue. No mitotic figure was observed in LM. AgNOR was more abundant in number in LS than LM (P < 0.001), but it had no direct relation to tumor size, number of cells in mitosis and patients' survival period. Immunohistochemical studies of Vim, Des, S100, FN and Cyt revealed that none of them was very helpful in the differential diagnosis of LM from LS.

Production of chymosin for the dairy industry by recombinant DNA technology

The increasing world production of cheese, coupled with a decline in the number of slaughtered calves, has stimulated a search for alternative sources of chymosin. This article briefly reviews microbial alternatives to chymosin and discusses chymosins produced using recombinant DNA technology. Recombinant chymosin represents one of the first successful applications of recombinant DNA technology in the food industry.