Prevalence and impact of neuropsychiatric symptoms in normal aging and neurodegenerative syndromes: A population-based study from Latin America

BACKGROUND

Neuropsychiatric symptoms (NPSs) are common in neurodegenerative diseases; however, little is known about the prevalence of NPSs in Hispanic populations.

METHODS

Using data from community-dwelling participants age 65 years and older enrolled in the 10/66 study (N = 11,768), we aimed to estimate the prevalence of NPSs in Hispanic populations with dementia, parkinsonism, and parkinsonism-dementia (PDD) relative to healthy aging. The Neuropsychiatric Inventory Questionnaire (NPI-Q) was used to assess NPSs.

RESULTS

NPSs were highly prevalent in Hispanic populations with neurodegenerative disease; approximately 34.3%, 56.1%, and 61.2% of the participants with parkinsonism, dementia, and PDD exhibited three or more NPSs, respectively. NPSs were the major contributor to caregiver burden.

DISCUSSION

Clinicians involved in the care of elderly populations should proactively screen for NPSs, especially in patients with parkinsonism, dementia, and PPD, and develop intervention plans to support families and caregivers. Highlights Neuropsychiatric symptoms (NPSs) are highly prevalent in Hispanic populations with neurodegenerative diseases. In healthy Hispanic populations, NPSs are predominantly mild and not clinically significant. The most common NPSs include depression, sleep disorders, irritability, and agitation. NPSs explain a substantial proportion of the variance in global caregiver burden.

Factors associated with cognitive impairment in Latin American older adults: A cross-sectional observational study of COVID-19 confinement

INTRODUCTION

The effects of COVID-19 confinement have been severe, especially in older adults. Therefore, we analyzed the factors associated with cognitive impairment (CI) in Latin America (LA).

METHODS

We conducted a cross-sectional observational study with a total of 5245 older adults from 10 countries in LA.

Measurement

We used the Telephone Montreal Cognitive Assessment (T-MoCA) and the Eight-item Informant Interview to Differentiate Aging and Dementia (AD8) scale.

RESULTS

We found that age, depressive symptomatology, bone fractures, being widowed, having a family member with dementia, and unemployment were associated with an increased risk of CI. In contrast, higher education, hypertension with continuous treatment, quarantine, and keeping stimulating cognitive and physical activities were associated with a lower probability of CI. No significant association was found between suffering from diabetes or being retired and CI.

DISCUSSION

It is essential to conduct follow-up studies on these factors, considering their relationship with CI and the duration of confinement.

Burden of Parkinsonism and Parkinson's Disease on Health Service Use and Outcomes in Latin America

BACKGROUND

Little is known about the burden of parkinsonism and Parkinson's disease (PD) in Latin America. Better understanding of health service use and clinical outcomes in PD is needed to improve its prognosis.

OBJECTIVE

The aim of the study was to estimate the burden of parkinsonism and PD in six Latin American countries.

METHODS

12,865 participants aged 65 years and older from the 10/66 population-based cohort study were analysed. Baseline assessments were conducted in 2003-2007 and followed-up 4 years later. Parkinsonism and PD were defined using current clinical criteria or self-reported diagnosis. Logistic regression models assessed the association between parkinsonism/PD with baseline health service use (community-based care or hospitalisation in the last 3 months) and Cox proportional hazards regression models with incident dependency (subjective assessment by interviewer based on informant interview) and mortality. Separate analyses for each country were combined via fixed effect meta-analysis.

RESULTS

At baseline, the prevalence of parkinsonism and PD was 7.9% (n = 934) and 2.6% (n = 317), respectively. Only parkinsonism was associated with hospital admission at baseline (OR 1.89, 95% CI 1.30-2.74). Among 7,296 participants without dependency at baseline, parkinsonism (HR 2.34, 95% CI 1.81-3.03) and PD (2.10, 1.37-3.24) were associated with incident dependency. Among 10,315 participants with vital status, parkinsonism (1.73, 1.50-1.99) and PD (1.38, 1.07-1.78) were associated with mortality. The Higgins I2 tests showed low to moderate levels of heterogeneity across countries.

CONCLUSIONS

Our findings show that older people with parkinsonism or PD living in Latin America have higher risks of developing dependency and mortality but may have limited access to health services.

Impact of quarantine due to COVID-19 pandemic on health and lifestyle conditions in older adults from Centro American countries

Background

The impact of quarantine in older adults have been reported in several studies with contradictory results, reporting from negative effects to no significant outcomes or even beneficial consequences. Heterogeneity in aging plays a role in each region, the aim of this study is to analyze the impact of quarantine on health conditions (physical and mental) and lifestyle in older adults in five Centro American countries during COVID-19 pandemic.

Method

In this cross-sectional study, n = 712 older adults 60 years and older from Mexico, Guatemala, El Salvador, Honduras and Costa Rica were assessed by telephone. Sociodemographic data, physical and mental health, lifestyle and quarantine conditions were asked previous informed consent.

Results

In general, mean of days in quarantine at the moment of the study was 142 days (approximately four months and three weeks). In the analysis of the impact of the days in quarantine effects were found on the frequency of falls, functional ability in Activities of Daily Living (ADL), general cognitive function, memory, orientation, language, frequency of drinking alcohol, having a balanced diet, and being active cognitively. Some differences were found between countries.

Conclusions

Effects of quarantine on older adults in Centro America, requires attention of governments and healthcare to prevent long term morbidity and disability, and to promote healthy aging.

Differences in body composition and growth persist postnatally in fetuses diagnosed with severe compared to mild fetal growth restriction

BACKGROUND

Fetal growth restriction (FGR) is most commonly diagnosed in pregnancy if the estimated fetal weight (EFW) is <  10th%. Those with abnormal Doppler velocimetry, indicating placental insufficiency and pathological FGR, demonstrate reduced fat and lean mass compared to both normally growing fetuses and FGR fetuses with normal Dopplers. The aim of this study was to determine how severity of FGR and abnormal Doppler velocimetry impacts neonatal body composition. Among a cohort of fetuses with an EFW <  10th%, we hypothesized that those with abnormal Dopplers and/or EFW <  3rd% would have persistent reductions in lean body mass and fat mass extending into the neonatal period compared to fetuses not meeting those criteria.

METHODS

A prospective cohort of FGR fetuses with an estimated fetal weight (EFW) <  10th% was categorized as severe (EFW <  3rd% and/or abnormal Dopplers; FGR-S) versus mild (EFW 3-10th% ; FGR-M). Air Displacement Plethysmography and anthropometrics were performed at birth and/or within the first 6-8 weeks of life.

RESULTS

FGR-S versus FGR-M were born one week earlier (P = 0.0024), were shorter (P = 0.0033), lighter (P = 0.0001) with smaller weight-for-age Z-scores (P = 0.0004), had smaller head circumference (P = 0.0004) and lower fat mass (P = 0.01) at birth. At approximately 6-8 weeks postmenstrual age, weight, head circumference, and fat mass were similar but FGR-S neonates were shorter (P = 0.0049) with lower lean mass (P = 0.0258).

CONCLUSION

Doppler velocimetry abnormalities in fetuses with an EFW <  10th% identified neonates who were smaller at birth and demonstrated catch-up growth by 6-8 weeks of life that favored fat mass accretion over lean mass and linear growth.

Frontotemporal Dementias in Latin America: History, Epidemiology, Genetics, and Clinical Research

Introduction: The historical development, frequency, and impact of frontotemporal dementia (FTD) are less clear in Latin America than in high-income countries. Although there is a growing number of dementia studies in Latin America, little is known collectively about FTD prevalence studies by country, clinical heterogeneity, risk factors, and genetics in Latin American countries. Methods: A systematic review was completed, aimed at identifying the frequency, clinical heterogeneity, and genetics studies of FTD in Latin American populations. The search strategies used a combination of standardized terms for FTD and related disorders. In addition, at least one author per Latin American country summarized the available literature. Collaborative or regional studies were reviewed during consensus meetings. Results: The first FTD reports published in Latin America were mostly case reports. The last two decades marked a substantial increase in the number of FTD research in Latin American countries. Brazil (165), Argentina (84), Colombia (26), and Chile (23) are the countries with the larger numbers of FTD published studies. Most of the research has focused on clinical and neuropsychological features (n = 247), including the local adaptation of neuropsychological and behavioral assessment batteries. However, there are little to no large studies on prevalence (n = 4), biomarkers (n = 9), or neuropathology (n = 3) of FTD. Conclusions: Future FTD studies will be required in Latin America, albeit with a greater emphasis on clinical diagnosis, genetics, biomarkers, and neuropathological studies. Regional and country-level efforts should seek better estimations of the prevalence, incidence, and economic impact of FTD syndromes.

A multi-mechanism approach reduces length of stay in the ICU for severe COVID-19 patients

PURPOSE

COVID-19 pandemic has multifaceted presentations with rising evidence of immune-mediated mechanisms underplay. We sought to explore the outcomes of severe COVID-19 patients treated with a multi-mechanism approach (MMA) in addition to standard-of-care (SC) versus patients who only received SC treatment.

MATERIALS AND METHODS

Data were collected retrospectively for patients admitted to the intensive care unit (ICU). This observational cohort study was performed at five institutions, 3 in the United States and 2 in Honduras. Patients were stratified for MMA vs. SC treatment during ICU stay. MMA treatment consists of widely available medications started immediately upon hospitalization. These interventions target immunomodulation, anticoagulation, viral suppression, and oxygenation. Primary outcomes included in-hospital mortality and length of stay (LOS) for the index hospitalization and were measured using logistic regression.

RESULTS

Of 86 patients admitted, 65 (76%) who had severe COVID-19 were included in the study; 30 (46%) patients were in SC group, compared with 35 (54%) patients treated with MMA group. Twelve (40%) patients in the SC group died, compared with 5 (14%) in the MMA group (p-value = 0.01, Chi squared test). After adjustment for gender, age, treatment group, Q-SOFA score, the MMA group had a mean length of stay 8.15 days, when compared with SC group with 13.55 days. ICU length of stay was reduced by a mean of 5.4 days (adjusted for a mean age of 54 years, p-value 0.03) and up to 9 days (unadjusted for mean age), with no significant reduction in overall adjusted mortality rate, where the strongest predictor of mortality was the use of mechanical ventilation.

CONCLUSION

The finding that MMA decreases the average ICU length of stay by 5.4 days and up to 9 days in older patients suggests that implementation of this treatment protocol could allow a healthcare system to manage 60% more COVID-19 patients with the same number of ICU beds.

On the Reconstitution of Photophosphorylation in CF1-Extracted Chloroplasts

1. A method for the reproducible preparation of CF1-depleted thylakoid membranes was established. By repeated washes with pyrophosphate solution and subsequent treatment with sucrose media, containing micromolar concentrations of Ca2+ or Mg2+, different degrees of CF1 depletion and uncoupling were adjusted.

2. The membranes were completely uncoupled when about 50% CF1 was removed. Re-coupling with isolated CF1 was maximal at this point. It decreased with progressive CF1 extraction.

3. The re-attached CF1 particles regained their ability of energy-dependent adenine nucleotide exchange, an essential reaction in photophosphorylation.

4. CF1-depleted membranes showed two main morphological alterations,

a. unstacknig of the grana, and

b. a perforation of the thylakoid membranes in those chloroplasts which showed a poor recoupling activity. Whereas CF1-depletion and unstacking were found to be reversible, the formation of holes was an irreversible effect.

5. The decreasing re-coupling activity was discussed in context to the irreversible perforation of the thylakoid membranes.

Regulation of aspartate-derived amino acid homeostasis in potato plants (Solanum tuberosum L.) by expression of E. coli homoserine kinase

The availability of the carbon backbone O-phosphohomoserine (OPHS) is critical to methionine (met) and threonine (thr) synthesis. OPHS derives from homoserine and is formed by homoserine kinase (HSK). To clarify the function of HSK in cellular metabolism, the E. coli HSK ortholog thrB was expressed in potato plants targeting the EcHSK protein to chloroplasts and to the cytosol. Both approaches resulted in up to 11 times increased total HSK enzyme activity. Transgenic plants exhibited reduced homoserine levels while met and thr did not accumulate significantly. However, the precursor cysteine and upstream intermediates of met such as cystathionine and homocysteine did indicating an accelerated carbon flow towards the end products. Coincidently, plants with elevated cytosolic levels of EcHSK exhibited a reduction in transcript levels of the endogenous HSK, as well as of threonine synthase (TS), cystathionine beta-lyase (CbL), and met synthase (MS). In all plants, cystathionine gamma-synthase (CgS) expression remained relatively unchanged from wild type levels, while S-adenosylmethionine synthetase (SAMS) expression increased. Feeding studies with externally supplied homoserine fostered the synthesis of met and thr but the regulation of synthesis of both amino acids retained the wild type regulation pattern. The results indicate that excess of plastidial localised HSK activity does not influence the de novo synthesis of met and thr. However, expression of HSK in the cytosol resulted in the down-regulation of gene expression of pathway genes probably mediated via OPHS. We integrated these data in a novel working model describing the regulatory mechanism of met and thr homeostasis.

Effect of sulfur availability on the integrity of amino acid biosynthesis in plants

Amino acid levels in plants are regulated by a complex interplay of regulatory circuits at the level of enzyme activities and gene expression. Despite the diversity of precursors involved in amino acid biosynthesis as providing the carbon backbones, the amino groups and, for the amino acids methionine and cysteine, the sulfhydryl group and despite the involvement of amino acids as substrates in various downstream metabolic processes, the plant usually manages to provide relatively constant levels of all amino acids. Here we collate data on how amino acid homeostasis is shifted upon depletion of one of the major biosynthetic constituents, i.e., sulfur. Arabidopsis thaliana seedlings exposed to sulfate starvation respond with a set of adaptation processes to achieve a new balance of amino acid metabolism. First, metabolites containing reduced sulfur (cysteine, glutathione, S-adenosylmethionine) are reduced leading to a number of downstream effects. Second, the relative excess accumulation of N over S triggers processes to dump nitrogen in asparagine, glutamine and further N-rich compounds like ureides. Third, the depletion of glutathione affects the redox and stress response system of the glutathione-ascorbate cycle. Thus, biosynthesis of aromatic compounds is triggered to compensate for this loss, leading to an increased flux and accumulation of aromatic amino acids, especially tryptophan. Despite sulfate starvation, the homeostasis is kept, though shifted to a new state. This adaptation process keeps the plant viable even under an adverse nutritional status.

Muscular activation patterns of healthy persons and low back pain patients performing a functional capacity evaluation test

The results of most reported studies show differences between the muscular activity of low back pain patients and healthy subjects, but the focus has usually been on trunk muscles only, and they have not involved work-related tests or exercises. The reintegration of chronic low back pain patients to job market is a common problem. Therefore assessment systems like the functional capacity evaluation (FCE) according to Isernhagen [S.J. Isernhagen, Work Injury: Management and Prevention, Aspen Publishers Inc., Gaithersburg, MD, 1988] are often used tools to determine the physical abilities and deficits of long-time incapacitated persons. The aim of the present study was to compare the healthy persons and chronic low back pain patients in performing a FCE-test and to analyse their muscular activation and motion patterns. The results indicate differences in the activation patterns of the groups in the test task "floor to waist lift" common in many occupations.

Engineering of cysteine and methionine biosynthesis in potato

Methionine and cysteine, two amino acids containing reduced sulfur, are not only an important substrate of protein biosynthesis but are also precursors of various other metabolites such as glutathione, phytochelatines, S-adenosylmethionine, ethylene, polyamines, biotin, and are involved as methyl group donor in numerous cellular processes. While methionine is an essential amino acid due to an inability of monogastric animals and human beings to synthesise this metabolite, animals are still able to convert methionine consumed with their diet into cysteine. Thus, a balanced diet containing both amino acids is necessary to provide a nutritionally favourable food or feed source. Because the concentrations of methionine and cysteine are often low in edible plant sources, e.g. potato, considerable efforts in plant breeding and research have been and are still performed to understand the physiological, biochemical, and molecular mechanisms that contribute to their synthesis, transport, and accumulation in plants. During the last decade molecular tools have enabled the isolation of most of the genes involved in cysteine and methionine biosynthesis, and the efficient plant transformation technology has allowed the creation of transgenic plants that are altered in the activity of individual genes. The physiological analysis of these transgenic plants has contributed considerably to our current understanding of how amino acids are synthesised. We focused our analysis on potato (Solanum tuberosum cv. Désirée) as this plant provides a clear separation of source and sink tissues and, for applied purposes, already constitutes a crop plant. From the data presented here and in previous work we conclude that threonine synthase and not cystathionine gamma-synthase as expected from studies of Arabidopsis constitutes the main regulatory control point of methionine synthesis in potato. This article aims to cover the current knowledge in the area of molecular genetics of sulfur-containing amino acid biosynthesis and will provide new data for methionine biosynthesis in solanaceous plants such as potato.

Enhanced cystathionine beta-lyase activity in transgenic potato plants does not force metabolite flow towards methionine

Cystathionine beta-lyase (CbL) catalyses the second step in higher-plant methionine biosynthesis. To further characterise the role of CbL in methionine biosynthesis, transgenic potato (Solanum tuberosum L.) plants were generated that express a potato cystathionine beta-lyase (StCbL; EC 4.4.1.8) under the control of the cauliflower mosaic virus 35 S promoter. Transgenic potato lines showed no visible phenotype but revealed an accumulation of both CbL transcript and protein. The enzymatic activity of CbL in these lines was up to 2.5-fold higher than that of wild-type plants. GC-MS measurements of aspartate-derived metabolites, however, showed no significant changes in content of amino acids and pathway intermediates when transgenic and wild-type plants were compared. CbL over-expression did not change the expression patterns and gene products of other pathway-relevant genes as evident from RNA and protein blot analyses. Despite the essential role of CbL in plant growth and development, the data presented indicate that the homologous over-expression of CbL is not in itself able to enhance metabolic flux towards methionine biosynthesis.

Antisense inhibition of threonine synthase leads to high methionine content in transgenic potato plants

Methionine (Met) and threonine (Thr) are members of the aspartate family of amino acids. In plants, their biosynthetic pathways diverge at the level of O-phosphohomo-serine (Ser). The enzymes cystathionine gamma-synthase and Thr synthase (TS) compete for the common substrate O-phosphohomo-Ser with the notable feature that plant TS is activated through S-adenosyl-Met, a metabolite derived from Met. To investigate the regulation of this branch point, we engineered TS antisense potato (Solanum tuberosum cv Désirée) plants using the constitutive cauliflower mosaic virus 35S promoter. In leaf tissues, these transgenics exhibit a reduction of TS activity down to 6% of wild-type levels. Thr levels are reduced to 45% wild-type controls, whereas Met levels increase up to 239-fold depending on the transgenic line and environmental conditions. Increased levels of homo-Ser and homo-cysteine indicate increased carbon allocation into the aspartate pathway. In contrast to findings in Arabidopsis, increased Met content has no detectable effect on mRNA or protein levels or on the enzymatic activity of cystathionine gamma-synthase in potato. Tubers of TS antisense potato plants contain a Met level increased by a factor of 30 and no reduction in Thr. These plants offer a major biotechnological advance toward the development of crop plants with improved nutritional quality.

Manipulation of thiol contents in plants

As sulfur constitutes one of the macronutrients necessary for the plant life cycle, sulfur uptake and assimilation in higher plants is one of the crucial factors determining plant growth and vigour, crop yield and even resistance to pests and stresses. Inorganic sulfate is mostly taken up as sulfate from the soil through the root system or to a lesser extent as volatile sulfur compounds from the air. In a cascade of enzymatic steps inorganic sulfur is converted to the nutritionally important sulfur-containing amino acids cysteine and methionine (Hell, 1997; Hell and Rennenberg, 1998; Saito, 1999). Sulfate uptake and allocation between plant organs or within the cell is mediated by specific transporters localised in plant membranes. Several functionally different sulfate transporters have to be postulated and have been already cloned from a number of plant species (Clarkson et al., 1993; Hawkesford and Smith, 1997; Takahashi et al., 1997; Yamaguchi, 1997). Following import into the plant and transport to the final site of reduction, the plastid, the chemically relatively inert sulfate molecule is activated through binding to ATP forming adenosine-5'-phosphosulfate (APS). This enzymatic step is controlled through the enzyme ATP-sulfurylase (ATP-S). APS can be further phosphorylated to form 3'-phosphoadenosine-5'-phosphosulfate (PAPS) which serves as sulfate donor for the formation of sulfate esters such as the biosynthesis of sulfolipids (Schmidt and Jäger, 1992). However, most of the APS is reduced to sulfide through the enzymes APS-reductase (APR) and sulfite reductase (SIR). The carbon backbone of cysteine is provided through serine, thus directly coupling photosynthetic processes and nitrogen metabolism to sulfur assimilation. L-serine is activated by serine acetyltransferase (SAT) through the transfer to an acetyl-group from acetyl coenzyme A to form O-acetyl-L-serine (OAS) which is then sulhydrylated using sulfide through the enzyme O-acetyl-L-serine thiol lyase (OAS-TL) forming cysteine. Cysteine is the central precursor of all organic molecules containing reduced sulfur ranging from the amino acid methionine to peptides as glutathione or phytochelatines, proteines, vitamines, cofactors as SAM and hormones. Cysteine and derived metabolites display essential roles within plant metabolism such as protein stabilisation through disulfide bridges, stress tolerance to active oxygen species and metals, cofactors for enzymatic reactions as e.g. SAM as major methylgroup donor and plant development and signalling through the volatile hormone ethylene. Cysteine and other metabolites carrying free sulfhydryl groups are commonly termed thioles (confer Fig. 1). The physiological control of the sulfate reduction pathway in higher plants is still not completely understood in all details. The objective of this paper is to summarise the available data on the molecular analysis and control of cysteine biosynthesis in plants, and to discuss potentials for manipulating the pathway using transgenic approaches.

Approaches towards understanding methionine biosynthesis in higher plants

Plants are able to synthesise all amino acids essential for human and animal nutrition. Because the concentrations of some of these dietary constituents, especially methionine, lysine, and threonine, are often low in edible plant sources, research is being performed to understand the physiological, biochemical, and molecular mechanisms that contribute to their transport, synthesis and accumulation in plants. This knowledge can be used to develop strategies allowing a manipulation of crop plants, eventually improving their nutritional quality. This article is intended to serve two purposes. The first is to provide a brief review on the physiology of methionine synthesis in higher plants. The second is to highlight some recent findings linked to the metabolism of methionine in plants due to its regulatory influence on the aspartate pathway and its implication in plant growth. This information can be used to develop strategies to improve methionine content of plants and to provide crops with a higher nutritional value.

Indirect RT-PCR in-situ hybridization: a novel non-radioactive method for detecting glucose-dependent insulinotropic peptide

To establish indirect in-situ PCR for the detection of intestinal peptide hormones, rat intestine and a murine intestinal tumor cell line, STC 1, were used. The results exhibited intensive staining of GIP-producing K-cells. Paraformaldehyde-fixed cryostat sections yielded the best results in signal to background ratio with RT-PCR in-situ hybridization. Moreover, it was possible to elevate the positive staining signal and to reduce background staining. Digoxigenin-labeled in-situ hybridization served as a control for specificity and sensitivity of GIP (glucose-dependent insulinotropic peptide) mRNA expression on cryostat as well as paraffin sections. In conclusion, this RT-PCR in-situ hybridization protocol proves to be a specific, sensitive and reliable non-radioactive technique for the detection of intestinal peptide hormone mRNA, especially in tissues or tumor cells where the application of ISH is limited.

Transgenic potato plants reveal the indispensable role of cystathionine beta-lyase in plant growth and development

Methionine (Met) is an essential amino acid that is often unavailable at sufficient dietary levels. In order to better understand Met pathway regulation, a cDNA encoding cystathionine beta-lyase (CbL; EC 4.4.1.8) has been cloned from Solanum tuberosum. An antisense construct of this gene was used to generate transgenic potato plants with reduced CbL levels. Transgenic plants exhibiting leaf CbL activity levels of up to 50% below wild-type levels were obtained. Metabolite analysis revealed a reduction in Met levels in these CbL antisense plants, as well as remarkable increases in the pathway intermediates cystathionine, homoserine and cysteine. Unexpectedly, an increase in homocysteine was also observed. Levels of aspartate amino acid pathway intermediates (including aspartate, lysine and threonine) remained essentially unaffected. Neither transcript levels nor protein products of other pathway-relevant genes were altered significantly in these plants. CbL antisense plants exhibited an altered phenotype characterized by a bushy growth habit, small light-green leaves and small tubers. This phenotype could be alleviated upon Met supplementation, suggesting that low Met levels, rather than pathway intermediate accumulation, is responsible for the phenotypic effects of CbL transgene expression. These data unequivocally demonstrate the central role of CbL in Met biosynthesis, and, subsequently, in plant growth and development.

Elevation of the pacing threshold: a side effect in a patient with pacemaker undergoing therapy with doxorubicin and vincristine

A 56-year-old female patient with an IgG plasmocytoma first diagnosed 5 years before underwent 3 cycles of chemotherapy according to the VAD scheme. A VVI pacemaker had been implanted 3 years earlier. After each cycle, the output of the pacemaker had to be increased as the pacing threshold had increased, resulting in a slow pulse. This case demonstrates that patients with a pacemaker that undergo chemotherapy with cardiotoxic agents must be followed carefully.

Expression of threonine synthase from Solanum tuberosum L. is not metabolically regulated by photosynthesis-related signals or by nitrogenous compounds

Although the control of carbon fixation and nitrogen assimilation has been studied in detail, little is known about the regulation of carbon and nitrogen flow into amino acids. In this paper the isolation of a cDNA encoding threonine synthase is reported (TS; EC 4.2.99.2) from a leaf lambda ZAP II-library of Solanum tuberosum L. and the transcriptional regulation of the respective gene expression in response to metabolic changes. The pattern of expression of TS by feeding experiments of detached petioles revealed that TS expression is regulated neither by photosynthesis-related metabolites nor by nitrogenous compounds. The present study suggests that the regulation of the conversion of aspartate to threonine is not controlled at the transcript level of TS. The nucleotide and deduced amino acid sequences of potato TS show homology to other known sequences from Arabidopsis thaliana and microorganisms. TS is present as a low copy gene in the genome of potato as demonstrated in Southern blot analysis. When cloned into a bacterial expression vector, the cDNA did functionally complement the Escherichia coli mutant strain Gif41. TS transcript was found in all tissues of potato and was most abundant in flowers and source leaves.

Expression of a bacterial serine acetyltransferase in transgenic potato plants leads to increased levels of cysteine and glutathione

The coding sequence of the wild-type, cys-sensitive, cysE gene from Escherichia coli, which encodes an enzyme of the cysteine biosynthetic pathway, namely serine acetyltransferase (SAT, EC 2.3.1. 30), was introduced into the genome of potato plants under the control of the cauliflower mosaic virus 35S promoter. In order to target the protein into the chloroplast, cysE was translationally fused to the 5'-signal sequence of rbcS from Arabidopsis thaliana. Transgenic plants showed a high accumulation of the cysE mRNA. The chloroplastic localisation of the E. coli SAT protein was demonstrated by determination of enzymatic activities in enriched organelle fractions. Crude leaf extracts of these plants exhibited up to 20-fold higher SAT activity than those prepared from wild-type plants. The transgenic potato plants expressing the E. coli gene showed not only increased levels of enzyme activity but also exhibited elevated levels of cysteine and glutathione in leaves. Both were up to twofold higher than in control plants. However, the thiol content in tubers of transgenic lines was unaffected. The alterations observed in leaf tissue had no effect on the expression of O-acetylserine(thiol)-lyase, the enzyme which converts O-acetylserine, the product of SAT, to cysteine. Only a minor effect on its enzymatic activity was observed. In conclusion, the results presented here demonstrate the importance of SAT in plant cysteine biosynthesis and show that production of cysteine and related sulfur-containing compounds can be enhanced by metabolic engineering.

Molecular cloning and expression analyses of mitochondrial and plastidic isoforms of cysteine synthase (O-acetylserine(thiol)lyase) from Arabidopsis thaliana

Cysteine synthase, the key enzyme for fixation of inorganic sulfide, catalyses the formation of cysteine from O-acetylserine and inorganic sulfide. Here we report the cloning of cDNAs encoding cysteine synthase isoforms from Arabidopsis thaliana. The isolated cDNA clones encode for a mitochondrial and a plastidic isoform of cysteine synthase (O-acetylserine (thiol)-lyase, EC 4.2.99.8), designated cysteine synthase C (AtCS-C, CSase C) and B (AtCS-B; CSase B), respectively. AtCS-C and AtCS-B, having lengths of 1569-bp and 1421-bp, respectively, encode polypeptides of 430 amino acids (approximately 45.8 kD) and of 392 amino acids (approximately 41.8 kD), respectively. The deduced amino acid sequences of the mitochondrial and plastidic isoforms exhibit high homology even with respect to the presequences. The predicted presequence of AtCS-C has a N-terminal extension of 33 amino acids when compared to the plastidic isoform. Northern blot analysis showed that AtCS-C is higher expressed in roots than in leaves whereas the expression of AtCS-B is stronger in leaves. Furthermore, gene expression of both genes was enhanced by sulfur limitation which in turn led to an increase in enzyme activity in crude extracts of plants. Expression of the AtCS-B gene is regulated by light. The mitochondrial, plastidic and cytosolic (Hesse and Altmann, 1995) isoforms of cysteine synthase of Arabidopsis are able to complement a cysteine synthase-deficient mutant of Escherichia coli unable to grow on minimal medium without cysteine, indicating synthesis of functional plant proteins in the bacterium. Two lines of evidence proved that AtCS-C encodes a mitochondrial form of cysteine synthase; first, import of in vitro translation products derived from AtCS-C in isolated intact mitochondria and second, Western blot analysis of mitochondria isolated from transgenic tobacco plants expressing AtCS-C cDNA/c-myc DNA fusion protein.

Interactions between pacemakers and security systems

Electromagnetic fields arising from a variety of different sources have been shown to interfere with normal pacemaker function. This study evaluated the possible interactions between two modern security systems and different pacemaker types. Fifty-three patients (27 single chamber pacemakers, 25 dual chamber pacemakers) have been tested routinely for their pacemaker function. Thirty-eight patients presented with unipolar sensing and 15 with bipolar sensing. The patients were asked to walk through an installed security system, an antitheft device, and electromagnetic access device with different field strengths while a six-channel ECG monitored the patients. The pacemaker systems were first measured in their basic programmed modes, then the intervention frequency was changed to 100/min and, thereafter, the maximum sensitivity without T wave oversensing was added. In the security system with the highest field strength (2,700 mA/m), a pacemaker malfunction could be observed in 13% of the monitored patients. In one case, a pacemaker (VVIR) switched to ventricular safety pacing (VOO mode). In the security system with the lower field strength (1,600 mA/m) we found a pacemaker malfunction in 4% of the tested patients. In the antitheft device (50 mA/m), in the electromagnetic access device (300 mA/m), and in pacemaker systems with bipolar sensing, none of these dysfunctions were observed. Phantom programming as described previously did not occur in any of the systems. Persons who are often in the vicinity of security systems should be equipped with a bipolar pacemaker system. Our findings indicate that patients with pacemakers should avoid contact with security systems.

Central somatosensory conduction time in severely growth-stunted children

To examine the effects of chronic malnutrition on central nervous system function, we used the somatosensory evoked potential to measure the central conduction time of 20 children aged 7-8 y with heights below the third percentile for their age and 20 control children in Honduras. The two groups differed significantly in socioeconomic status, achievement in Bender's neurointegrative test, and hematocrit, but not in birth weight. After median nerve stimulation, the mean central conduction time (interpeak latency between N13 and N20) for the growth-stunted group (6.19 +/- 0.52 ms) did not differ significantly from that of the control subjects (6.30 +/- 0.58 ms), suggesting appropriate myelination and fiber diameter. Somatosensory tracts may escape damage resulting from postnatal dietary deficiencies because myelination in these tracts is almost complete at birth.

Papillary muscle injury after blunt chest trauma

In many cases blunt chest trauma involves cardiac lesions, such as pericardial effusion, aneurysma dissecans, or valvular rupture. Early diagnosis with routine transthoracic and/or transesophageal echocardiography is essential to prevent a fatal outcome. In the case reported, a previously healthy 68-year-old woman fell 7 meters from the roof of a barn and sustained blunt injury to the chest as well as fractures of the face. Physical examination revealed a systolic murmur at the cardiac apex, and chest x-ray film showed a severe pulmonary edema. Transesophageal echocardiography demonstrated a ruptured anterolateral papillary muscle with fourth degree mitral insufficiency. An immediate mitral valve replacement was necessary.

Expression analysis of a sucrose synthase gene from sugar beet (Beta vulgaris L.)

To investigate the expression pattern of sucrose synthase, a cDNA from tap roots of sugar beet (Beta vulgaris L.) was isolated using a heterologous sucrose synthase cDNA from potato. The 2762 bp long cDNA clone designated SBSS 1 encodes for a 822 amino acid polypeptide of a predicted molecular mass of 93.7 kDa. The deduced amino acid sequence of sugar beet sucrose synthase has homologies of 65-70% when compared to predicted amino acid sequences of sucrose synthases from other species. RNA blot analysis shows that SBSS1 is expressed most predominant in tap root under normal growth conditions. Cold treatment and anaerobiosis lead to an increase in the steady-state levels of SBSS 1 mRNA in leaf and root tissue. In tap root slices, sugars in various concentrations had no influence on the SBSS 1 transcript level. On the other hand, wounding resulted in a decreased transcript level.

An improved method for generating subtracted cDNA libraries using phage lambda vectors

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Cloning and expression analysis of sucrose-phosphate synthase from sugar beet (Beta vulgaris L.)

A cDNA clone encoding a sucrose-phosphate synthase from sugar beet (BvSPS 1) has been isolated by screening a tap root-specific cDNA library using a heterologous SPS cDNA from spinach. The 3635 bp sugar beet cDNA codes for a 1045 amino acid polypeptide with a predicted molecular mass of 118 kDa. The deduced amino acid sequence of sugar beet SPS shows homologies with SPS from maize (71% identity) and spinach (77% identity). Genomic Southern blot analysis suggests that BvSPS 1 is a low-copy-number gene. RNA blot analysis of sink and source leaves, root and tap root tissue shows that SPS 1 is expressed in an organ-specific manner, being predominantly active in tap root. Incubation of detached leaves of sugar beet in light in glucose-containing media leads to an accumulation of the SPS transcript, while sucrose feeding reduces the steady-state level of the mRNA.

"Human pancreas-specific protein" (procarboxypeptidase B): a valuable marker in pancreatitis?

Human pancreas-specific protein (PASP) has been characterized previously as a serum marker for pancreatitis. It was then identified as pancreatic procarboxypeptidase B (PCB). The aim of the present study was to verify the usefulness of PASP (PCB) as a serum marker in patients with acute (n = 20) and chronic (n = 12) pancreatitis and in those following endoscopic retrograde cholangiopancreaticography (ERCP) (n = 44). Serum PASP values were analyzed by radioimmunoassay, with a range of normal values between 15 and 111 ng/ml. Between April 1992 and September 1992, 20 subjects (19-86 years of age) with acute pancreatitis (alcoholic, 8; biliary, 8; other, 4) were studied. We found edematous pancreatitis in 17 cases and severe hemorrhagic pancreatitis in three cases. At admission, peak levels of PASP (average value, 1,976 +/- 329 ng/ml), pancreatic isoamylase (942 +/- 151 U/L) and lipase (2,946 +/- 534 U/L) were detected in 15 of 20, 16 of 20, and 12 of 20 cases, respectively. The etiology of the pancreatitis had no influence on the PASP values. Furthermore, 10 patients with alcoholic and two patients with nonalcoholic chronic pancreatitis (29-67 years of age) were studied. The average peak level of PASP was 1,229 +/- 434 ng/ml. In this group, PASP paralleled the time course of amylase and lipase. Maximal PASP, amylase, and lipase levels were found in 11 of 12, nine of 12, and five of 12 patients, respectively, on the day of admission. ERCP was performed in 44 patients (36-87 years of age), demonstrating common bile duct stones in 16 and bile or pancreatic ductal tumors in 15 cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Early malnutrition followed by nutritional restoration lowers the conduction velocity and excitability of the corticospinal tract

The physiological sequelae of undernutrition were investigated in rats that were undernourished from day 1-21 and subsequently free-fed to 75 days of age. Population responses were recorded in the corticospinal tract following surface stimulation of the motor cortex, which activates corticospinal cells directly, and also indirectly via cortical synapses. The conduction velocity of the fastest corticospinal fibers in 15 malnourished rats was 16.9 m/s, significantly slower (P < 0.001) than the 20.0 m/s observed in 26 controls. In addition, the excitability of corticospinal neurons to direct stimulation was reduced as much as 67% in malnourished rats, while no effect on synaptic activation was observed. Our findings suggest that early malnutrition reduces the number of large fibers in the adult corticospinal tract. These results are discussed with respect to known morphological and behavioral effects of malnutrition in rats and their relevance to humans.

Glucocorticoid receptor binding site in the mouse alpha-amylase 2 gene mediates response to the hormone

Amylase gene expression has been shown to be positively regulated by glucocorticoids. Previous reports have suggested that this effect is indirect. We have addressed this question in a mouse exocrine pancreas cell line, 266-6, in which basal level of expression of amylase mRNA is low but inducible by glucocorticoids. In these cells the effect of glucocorticoids is not inhibited by cycloheximide at early time points. Reporter plasmids containing 224 base pairs of mouse amylase 5'-flanking DNA are positively regulated by glucocorticoids in gene transfer experiments. Glucocorticoid receptor purified from rat liver binds to the amylase promoter from position -56 to -33 and at the start of transcription. Site-directed mutation at the upstream position (-47 to -42) eliminates response to glucocorticoids in transient gene transfer experiments. Thus, glucocorticoid regulation of the mouse amylase gene is a direct effect and is mediated via a receptor binding site in the promoter region of the gene. Inhibition of the hormone response by cycloheximide at later time points after induction suggests the additional requirement for a short-lived factor. The DNA binding domain of the glucocorticoid receptor binds to a single site in the amylase promoter as a monomer, suggesting that both receptor binding sites as well as an additional short-lived factor are required to obtain induction.

[Spontaneous rupture of the spleen in infectious mononucleosis]

Rupture of the spleen occurred in two patients (a man of 32 and a girl of 16 years) with serologically proven infectious mononucleosis. No history of trauma as a cause of the rupture could be elicited in either patient, despite intensive questioning. Abdominal symptoms were left-sided upper abdominal pain radiating into the left shoulder (Kehr's sign). The suspected diagnosis was confirmed by ultrasound demonstration of free abdominal fluid and abnormal splenic structure. Splenectomy had to be performed in both patients.