How to present and summarize a scientific journal article.

The success of a journal club hinges on the presentation of articles that are both relevant and scientifically robust. It's insufficient for presenters to merely read through an article and highlight a few points without a clear focus. A strong presentation should thoroughly describe the relevance and validity of the study, offer a critique, suggest how further research might address the issue, and discuss the implications for patient care. Selecting the right article is crucial. It is recommended to begin the presentation with a case scenario to emphasize the article's clinical relevance and to revisit the case at the conclusion of the presentation. The components of the article presentation should include background information, methodology and results, and the authors' discussion. Additionally, the presenter should critique the article's validity, noting any potential biases, evaluating the risks and costs of the proposed intervention, and assessing how well the article supports its hypothesis. The presentation should conclude with a summary statement that includes conclusions, implications, and future directions. Having a structured process for journal club presentations guides presenters and ensures that attendees derive maximum benefit from the educational activity. This organized approach fosters a deeper understanding and encourages critical thinking among participants.

Prosthesis for Unilateral Isolated Proximal Focal Femoral Deficiency: A Case Report and Review of the Literature.

A 14-month-old female child was brought to us by her parents with the complaint of progressive shortening of her right lower limb since birth. Born to non-consanguineous parents from a poor socioeconomic background, her birth and antenatal history were uneventful. Physical examination revealed no facial dysmorphism; however, her right thigh was short and bulky, and there were restrictions in hip, knee, and ankle movements. The pediatric evaluation showed normal growth and development. X-rays confirmed proximal femoral focal deficiency (PFFD) of the right lower limb. After extensive parental counseling regarding the condition, potential interventions, and outcomes, the parents opted for prosthetic management due to concerns about surgical costs, risks, and cosmetic outcomes. A custom-made extension prosthesis was prepared for the limb and was fit. At a follow-up of one year, the child exhibited a normal gait pattern with stable hip, knee, and ankle motion, and the parents expressed satisfaction with the prosthetic management, preferring it over surgical intervention for the time being.

A genetic mouse model mimicking MET related human osteofibrous dysplasia is characterized by delays in fracture repair and defective osteogenesis.

Osteofibrous dysplasia (OFD) is a rare, benign, fibro-osseous lesion that occurs most commonly in the tibia of children. Tibial involvement leads to bowing and predisposes to the development of a fracture which exhibit significantly delayed healing processes, leading to prolonged morbidity. We previously identified gain-of-function mutations in the MET gene as a cause for OFD. In our present study, we test the hypothesis that gain-of-function MET mutations impair bone repair due to reduced osteoblast differentiation. A heterozygous Met exon 15 skipping (MetΔ15-HET) mouse was created to imitate the human OFD mutation. The mutation results in aberrant and dysregulation of MET-related signaling determined by RNA-seq in the murine osteoblasts extracted from the wide-type and genetic mice. Although no gross skeletal defects were identified in the mice, fracture repair was delayed in MetΔ15-HET mice, with decreased bone formation observed 2-week postfracture. Our data are consistent with a novel role for MET-mediated signaling regulating osteogenesis.

General Practitioners' Experience of Remote Consultations by Telephone in the General Practice Setting during the COVID-19 Pandemic.

The coronavirus disease 2019 (COVID 19) pandemic brought substantial changes in the way doctors used to interact with patients. In the general practice, consultation over the phone has become a norm now. However, it is not well known how this new mode of consultation affected clinicians' practices. Objective of this study was to find out if doctors working in the general practices were trained enough for telephonic consultation and how this new mode of consultation affected their clinical practice in general. It was an online survey. Information was gathered by using an online questionnaire which was sent electronically to general practitioners (GPs) and general practitioner speciality trainees (GPSTs) working in the general practices based in Leicestershire. Data were analyzed by using software SPSS. Descriptive characteristics of participants were reported in terms of numbers and percentages, whereas Chi square test was run to assess if there is a difference between GPs and GPSTs in terms of their experience of remote consultations by telephone. The questionnaire response rate was 69.3% (n = 133/192). Of the total, 54.1% (n = 72/133) of participants were women. About 36% (n = 48/133) of the participants were GPSTs, whereas 64% (n = 85/133) were qualified GPs. Not having enough training for phone consultation, technical issues during consultation, inadequate supervision framework, difficulties in building therapeutic alliance with patients, making diagnosis and risk assessment, and increased duration of consultation were identified as issues. Similarly, concerns around patients' confidentiality and medico legal issues were highlighted. GPs and GPSTs reported similar difficulties. In conclusion, lack of training for the telephonic consultation has been identified as a unanimous issue along with other challenges to phone consultations. There is an urgent need to take measures to make telephone consultation more successful, enjoyable, and safe for patient care by addressing identified issues. Larger studies with representative samples are needed to increase generalizability of our findings.

How people learn: insights for medical faculty.

To increase medical students' and residents' understanding and retention, faculty need to teach from a knowledge standpoint and understanding of how individuals learn. We know from cognitive information processing that learners remember only a small portion of what they read or hear but remember up to 90% of information when strong active learning modalities are included. Faculty also need to be aware of different learning styles-kinesthetic, visual, and auditory-and ensure that they are including methods that can reach all learners. The cognitive and information processing theories of learning provide insights to educators related to building on prior knowledge from learning and limiting the number of points taught so learners can process and retain the information. Strategies such as a flipped classroom model and question clicker technology can assist in reaching learning goals. Fundamental conditions for learning include awareness, interest, motivation, relevance, engagement, reinforcement, and support.

Comparison of hospitalist service staffing models at Baylor University Medical Center.

Background: Baylor University Medical Center benefits from being a quaternary care center with 900+ licensed beds and multiple different models to staff patients on the hospitalist service. These models include hospitalist only, resident teaching teams, and two different advanced practice practitioner teams. The primary goal of this study was to assess these different staffing models and to ascertain which model, if any, has better outcomes related to length of stay, total hospital charges, 30-day readmission rates, patient satisfaction, hospital-acquired infections, mortality, and early discharges. Methods: The study was an observational retrospective chart review of all discharges from the hospitalist service at Baylor University Medical Center from October 1, 2021, to February 28, 2022. Patients were included if the hospitalist team was the primary team of record at the time of discharge. A total of 7803 patients were included. Results: There was no difference in patient satisfaction, hospital-acquired infections, and mortality between the groups. The teaching teams had a shorter length of stay before the removal of outliers. Independent advanced practice practitioners reliably had more patients discharged before 11:30 am. Results support the concept of continuity of care, as well as lower patient-to-provider ratios. Conclusions: These results have actionable implications that support the use of different advanced practice practitioner teams for the safe care of hospitalized patients as well as the safe integration of residents into patient care.

COVID-19's impact on family medicine resident training and wellness.

Background: The COVID-19 global pandemic has raised many challenges in training family medicine residents. Family medicine is at the frontline for treating and managing patients with COVID-19. Attention is needed on the critical issue of the effect of the pandemic on resident training, the safety of those performing needed medical services, and the psychological well-being of trainees. Methods: We performed a cross-sectional, 25-question survey-based study to evaluate the perceived effect of the COVID-19 pandemic on family medicine residents' training and residents' well-being in the state of Texas. Results: A total of 250 Texas-based family medicine residents were surveyed with a response rate of 12.8% (n = 32). After the pandemic began, all residents worried about exposing their loved ones to COVID-19, and 65% felt like the COVID-19 pandemic negatively impacted their training overall. Respondents indicated that changes occurred in their respective residency curricula that altered training such as canceling of scheduled lectures (84.3%) and more telemedicine visits (56.25%). There was a significant difference for postgraduate year level and the effect on rotation assignments, with more disruption to the first- and third-year residents (P = 0.03). Conclusions: The COVID-19 pandemic has had a notable impact on the perception of quality of training and mental health within family medicine. Our findings may guide programs in how to proactively target pandemic-related training challenges.

Retinal Phenotyping of a Murine Model of Lafora Disease.

Lafora disease (LD) is a progressive neurologic disorder caused by biallelic pathogenic variants in EPM2A or EPM2B, leading to tissue accumulation of polyglucosan aggregates termed Lafora bodies (LBs). This study aimed to characterize the retinal phenotype in Epm2a-/- mice by examining knockout (KO; Epm2a-/-) and control (WT) littermates at two time points (10 and 14 months, respectively). In vivo exams included electroretinogram (ERG) testing, optical coherence tomography (OCT) and retinal photography. Ex vivo retinal testing included Periodic acid Schiff Diastase (PASD) staining, followed by imaging to assess and quantify LB deposition. There was no significant difference in any dark-adapted or light-adapted ERG parameters between KO and WT mice. The total retinal thickness was comparable between the groups and the retinal appearance was normal in both groups. On PASD staining, LBs were observed in KO mice within the inner and outer plexiform layers and in the inner nuclear layer. The average number of LBs within the inner plexiform layer in KO mice were 1743 ± 533 and 2615 ± 915 per mm2, at 10 and 14 months, respectively. This is the first study to characterize the retinal phenotype in an Epm2a-/- mouse model, demonstrating significant LB deposition in the bipolar cell nuclear layer and its synapses. This finding may be used to monitor the efficacy of experimental treatments in mouse models.

Murine typhus.

Murine typhus is a rare condition caused by the gram-negative bacterium Rickettsia typhi which classically presents with the triad of fever, rash, and headache. Herein we report a rare presentation of murine typhus in an adult who presented predominantly with fever and gastrointestinal symptoms. Initial imaging showed cardiomegaly and hepatosplenomegaly, which led to further workup revealing rickettsial disease. Although this illness is considered a rare diagnosis in the emergency department, every person with a pet that might have fleas is susceptible to it.

The Influence of Static Load and Sideways Impact Fall on Extramedullary Bone Plates Used to Treat Intertrochanteric Femoral Fracture: A Preclinical Strength Assessment.

Hip fracture accounts for a large number of hospitalizations, thereby causing substantial economic burden. Majority (> 90%) of all hip fractures are associated to sideways fall. Studies on sideways fall usually involve loading at quasi-static or at constant displacement rate, which neglects the physics of actual fall. Understanding femur resonance frequency and associated mode shapes excited by dynamic loads is also critical. Two commercial extramedullary implants, proximal femoral locking plate (PFLP) and variable angle dynamic hip screw (VA-DHS), were chosen to carry out the preclinical assessments on a simulated Evans-I type intertrochanteric fracture. In this study, we hypothesized that the behavior of the implant depends on the loading types-axial static and transverse impact-and a rigid implanted construct will absorb less impact energy for sideways fall. The in silico models were validated using experimental measurements of full-field strain data obtained from a 2D digital image correlation (DIC) study. Under peak axial load of 3 kN, PFLP construct predicted greater axial stiffness (1.07 kN/mm) as opposed to VA-DHS (0.85 kN/mm), although the former predicted slightly higher proximal stress shielding. Further, with greater mode 2 frequency, PFLP predicted improved performance in resisting bending due to sideways fall as compared to the other implant. Overall, the PFLP implanted femur predicted the least propensity to adverse stress intensities, suggesting better structural rigidity and higher capacity in protecting the fractured femur against fall.

Primary care physician and resident perceptions of gun safety counseling.

A significant public health burden exists related to firearm-related injuries in the United States. Primary care physicians (PCPs) find themselves on the frontline to address it. This study aimed to determine if PCPs feel prepared and responsible for providing firearm safety counseling. Data were gathered via a direct 23-question survey of family medicine, internal medicine, and pediatric physicians and residents in North and Central Texas between May 2019 and January 2020. The survey was delivered to 518 outpatient providers, with a 24% response rate. Associations were assessed by chi-square/Fisher's exact test. A total of 62% agreed that preventable firearm death is an important health issue and PCPs can have a positive effect; 10% felt their residency provided or provides opportunities to learn about firearm safety and how to counsel patients; 55% agreed that a standardized tool to question and counsel patients on firearm safety such as a template in the electronic health record would be useful; and 68% stated they would use a standardized template in their practice if proven to reduce firearm-related injuries. Physicians who had received training in residency felt their knowledge was adequate to be able to provide meaningful counseling to patients (P < 0.001). In conclusion, PCPs are pivotal in addressing firearm safety. A formal curriculum across primary care specialties' graduate education programs should be developed to improve physicians' competency in addressing firearm safety. Further investigation into standardized tools that could be implemented into an electronic health record may help bridge the gap from awareness to implementation of interventions.

Hypomorphic GINS3 variants alter DNA replication and cause Meier-Gorlin syndrome.

The eukaryotic CDC45/MCM2-7/GINS (CMG) helicase unwinds the DNA double helix during DNA replication. The GINS subcomplex is required for helicase activity and is, therefore, essential for DNA replication and cell viability. Here, we report the identification of 7 individuals from 5 unrelated families presenting with a Meier-Gorlin syndrome-like (MGS-like) phenotype associated with hypomorphic variants of GINS3, a gene not previously associated with this syndrome. We found that MGS-associated GINS3 variants affecting aspartic acid 24 (D24) compromised cell proliferation and caused accumulation of cells in S phase. These variants shortened the protein half-life, altered key protein interactions at the replisome, and negatively influenced DNA replication fork progression. Yeast expressing MGS-associated variants of PSF3 (the yeast GINS3 ortholog) also displayed impaired growth, S phase progression defects, and decreased Psf3 protein stability. We further showed that mouse embryos homozygous for a D24 variant presented intrauterine growth retardation and did not survive to birth, and that fibroblasts derived from these embryos displayed accelerated cellular senescence. Taken together, our findings implicate GINS3 in the pathogenesis of MGS and support the notion that hypomorphic variants identified in this gene impaired cell and organismal growth by compromising DNA replication.

Expression profiling of TaARGOS homoeologous drought responsive genes in bread wheat.

Drought tolerant germplasm is needed to increase crop production, since water scarcity is a critical bottleneck in crop productivity worldwide. Auxin Regulated Gene involved in Organ Size (ARGOS) is a large protein family of transcription factors that plays a vital role in organ size, plant growth, development, and abiotic stress responses in plants. Although, the ARGOS gene family has been discovered and functionalized in a variety of crop plants, but a comprehensive and systematic investigation of ARGOS genes in locally used commercial wheat cultivars is still yet to be reported. The relative expression of three highly conserved TaARGOS homoeologous genes (TaARGOS-A, TaARGOS-B, TaARGOS-D) was studied in three drought-tolerant (Pakistan-2013, NARC-2009 and NR-499) and three sensitive (Borlaug-2016, NR-514 and NR-516) wheat genotypes under osmotic stress, induced by PEG-6000 at 0 (exogenous control), 2, 4, 6, and 12 h. The normalization of target genes was done using ß-actin as endogenous control, whereas DREB3, as a marker gene was also transcribed, reinforcing the prevalence of dehydration in all stress treatments. Real-time quantitative PCR revealed that osmotic stress induced expression of the three TaARGOS transcripts in different wheat seedlings at distinct timepoints. Overall, all genes exhibited significantly higher expression in the drought-tolerant genotypes as compared to the sensitive ones. For instance, the expression profile of TaARGOS-A and TaARGOS-D showed more than threefold increase at 2 h and six to sevenfold increase after 4 h of osmotic stress. However, after 6 h of osmotic stress these genes started to downregulate, and the lowest gene expression was noticed after 12 h of osmotic stress. Among all the homoeologous genes, TaARGOS-D, in particular, had a more significant influence on controlling plant growth and drought tolerance as it showed the highest expression. Altogether, TaARGOSs are involved in seedling establishment and overall plant growth. In addition, the tolerant group of genotypes had a much greater relative fold expression than the sensitive genotypes. Ultimately, Pakistan-2013 showed the highest relative expression of the studied genes than other genotypes which shows its proficiency to mitigate osmotic stress. Therefore, it could be cultivated in arid and semi-arid regions under moisture-deficient regimes. These findings advocated the molecular mechanism and regulatory roles of TaARGOS genes in plant growth and osmotic stress tolerance in contrasting groups of wheat genotypes, accompanied by the genetic nature of identified genotypes in terms of their potential for drought tolerance.

Abstracts from the Seventh Annual Baylor University Medical Center Medical Education Research Forum 2021.

The Baylor University Medical Center Department of Medical Education hosted its seventh annual Medical Education Research Forum on April 21, 2021, to showcase the research efforts of its medical students, residents, and fellows. Thirty-six posters were shared and 18 oral presentations were given. Here we present 17 award-winning abstracts.

Phenotyping for drought resistance in bread wheat using physiological and biochemical traits.

Drought is one of the most prominent limiting factors that negatively affect crop productivity by manipulating its physiological pathway. One hundred twenty diverse bread wheat genotypes were used in a pot experiment to explore the relationship among their fifteen physio-biochemical traits (PBT) by using multivariate analysis, heatmapping and stress tolerance index (STI) for grain yield as a marker trait to identify high yielding genotype with maximum stress tolerance capability. Increased proline and sugar accumulation were observed from control to moisture deficient environments by 159% and 122%, respectively. Moreover, leaf membrane stability index (LMSI), leaf relative water content (LRWC), relative dry weight (RDW), chlorophyll content, leaf surface area (LSA), Leaf succulence (LS), canopy temperature depression (CTD), relative excised leaf water loss (RELWL) and leaf osmotic potential (LOP) showed significantly decreasing trend in drought stress treatment as compared to well-watered plants by -21%, -21%, -34%, -22%, -38%, -37%, -46%, -18% and -35% respectively. Additionally, principal component analysis and genotype by trait biplot analysis showed that initial 7 principal components (PC1 to PC7) represented 77.27% and 79.02% of total cumulative variation under control and drought stress respectively. Genotypic-Phenotypic correlation revealed that most of the attributes were higher in case of genotypic correlation component (rg) as compared to the phenotypic correlation component (rp) indicating more genetic association between traits. The darker and lighter colour scale produced by heatmap exhibited contrasting nature of genotypes, as positive side with higher values represented drought resistance while values on the negative side with lower values showed susceptible performance of genotypes. Our results concluded that the studied PBT associated with STI for grain yield are the main factors which may contribute in improved productivity of wheat crop and if these traits show appropriate performance under stress condition the crop will show the more productive returns under changing climate.

Use of oral rivaroxaban in cerebral venous thrombosis.

BACKGROUND: Cerebral venous thrombosis (CVT) is an uncommon cause of stroke in humans and the mainstay of treatment is anticoagulation unless contraindicated. Non-vitamin K oral anticoagulants have not been duly evaluated in randomized controlled trials in CVT. OBJECTIVE: To compare the efficacy and safety of oral rivaroxaban with vitamin K anticoagulant (warfarin) in preventing recurrent venous thromboembolism (VTE) in patients with CVT. METHODS: Adult patients with CVT, who were stable after 5-12 days of treatment with parenteral heparin 1 mg/kg, were screened for eligibility. The patients were randomly divided into two groups to receive oral rivaroxaban 20-30 mg daily or warfarin 1, 3 or 5 mg daily (with the dose adjusted to maintain an INR of 2-3), for 3-12 months. Recanalization rates, periprocedural complications, and clinical outcomes were assessed by Magnetic Resonance Venography (MRV) and National Institutes of Health Stroke Scale (NIHSS) at 3rd, 6th and 12th month follow-ups. RESULTS: In total, 45 patients with CVT were randomized to the two treatment groups (21 to rivaroxaban and 24 to warfarin). Overall recanalization was achieved by 18 (86%) and 20 (83%) cases from rivaroxaban and warfarin group, respectively at 6th month follow-up; and by all 45 (100%) cases from the both groups at 12th month follow-up. Excellent outcome (NIHSS score 0) was obtained by 20 (95%) cases from rivaroxaban group at 3rd to 12th month follow-ups; and by 23 (96%) cases at 6th to 12th month follow-ups. There were no major bleeding events during the trial. None of the patients developed recurrence of thrombosis. Statistically, no significant difference between the two treatment groups in terms of recanalization and clinical outcomes could be observed. CONCLUSION: Rivaroxaban is a safe option in CVT however; larger randomized controlled studies will impact the results validity.

The pluripotency factor Nanog regulates pericentromeric heterochromatin organization in mouse embryonic stem cells.

An open and decondensed chromatin organization is a defining property of pluripotency. Several epigenetic regulators have been implicated in maintaining an open chromatin organization, but how these processes are connected to the pluripotency network is unknown. Here, we identified a new role for the transcription factor NANOG as a key regulator connecting the pluripotency network with constitutive heterochromatin organization in mouse embryonic stem cells. Deletion of Nanog leads to chromatin compaction and the remodeling of heterochromatin domains. Forced expression of NANOG in epiblast stem cells is sufficient to decompact chromatin. NANOG associates with satellite repeats within heterochromatin domains, contributing to an architecture characterized by highly dispersed chromatin fibers, low levels of H3K9me3, and high major satellite transcription, and the strong transactivation domain of NANOG is required for this organization. The heterochromatin-associated protein SALL1 is a direct cofactor for NANOG, and loss of Sall1 recapitulates the Nanog-null phenotype, but the loss of Sall1 can be circumvented through direct recruitment of the NANOG transactivation domain to major satellites. These results establish a direct connection between the pluripotency network and chromatin organization and emphasize that maintaining an open heterochromatin architecture is a highly regulated process in embryonic stem cells.

The histone chaperone DAXX maintains the structural organization of heterochromatin domains.

BACKGROUND: The death domain-associated protein (DAXX) collaborates with accessory proteins to deposit the histone variant H3.3 into mouse telomeric and pericentromeric repeat DNA. Pericentromeric repeats are the main genetic contributor to spatially discrete, compact, constitutive heterochromatic structures called chromocentres. Chromocentres are enriched in the H3K9me3 histone modification and serve as integral, functionally important components of nuclear organization. To date, the role of DAXX as an H3.3-specific histone chaperone has been investigated primarily using biochemical approaches which provide genome-wide views on cell populations and information on changes in local chromatin structures. However, the global chromatin and subnuclear reorganization events that coincide with these changes remain to be investigated. RESULTS: Using electron spectroscopic imagine (ESI), a specialized form of energy-filtered transmission electron microscopy that allows us to visualize chromatin domains in situ with high contrast and spatial resolution, we show that in the absence of DAXX, H3K9me3-enriched domains are structurally altered and become uncoupled from major satellite DNA. In addition, the structural integrity of nucleoli and the organization of ribosomal DNA (rDNA) are disrupted. Moreover, the absence of DAXX leads to chromatin that is more sensitive, on a global level, to micrococcal nuclease digestion. CONCLUSIONS: We identify a novel role of DAXX as a major regulator of subnuclear organization through the maintenance of the global heterochromatin structural landscape. As well, we show, for the first time, that the loss of a histone chaperone can have severe consequences for global nuclear organization.

An evaluation of nuclear factor kappa B expression in colorectal carcinoma: an analysis of 50 cases.

CONTEXT: There is a rising trend in the incidence of (colorectal carcinoma) colorectal cancer (CRC) in India. Nuclear factor kappa B (NFkB) is a transcription factor which belongs to the Rel family. It has an impact on phenomena such as apoptosis, tumor progression and differentiation. AIMS: (1) To evaluate the grade and stage in 50 cases of colorectal carcinoma. (2) To evaluate the NFkB translocation into the nucleus of the cells. (3) To compare the benign and malignant areas with the degree of NFkB translocation and compare the translocation with the grade and pathological stage. SUBJECTS AND METHODS: The grade and stage of the tumors was evaluated. NFkB staining was performed on the tissues. The results of the immunostaining were analyzed semi quantitatively as a percentage of positive cells. STATISTICAL ANALYSIS USED:  Statistical Package for Social Sciences 13.0 statistical package program (SPSS, Lead Technologies Inc, USA) for windows was used. Correlation was carried out using the Pearson's correlation co-efficient and the Chi-square test. RESULTS: There were 29 males (58%) and 21 females (42%). Most of the cases were well-differentiated adenocarcinomas (58%). There was a significant difference between NFkB translocation in the epithelial cells and lymphocytes in the benign and malignant areas (P - 0.04 and P - 0.001 respectively). There was a significant correlation between the grade of NFkB staining in the malignant epithelial cells with the tumor and nodal status (P - 0.001 and P - 0.001). CONCLUSIONS: It is likely that NFkB is an important factor in the pathogenesis of CRC. Further studies including therapeutic intervention using strategies which prevent activation of NFkB in colorectal carcinoma patients will tell if we could alter the course of the disease favorably.

Modulation of Higher Order Chromatin Conformation in Mammalian Cell Nuclei Can Be Mediated by Polyamines and Divalent Cations.

The organisation of the large volume of mammalian genomic DNA within cell nuclei requires mechanisms to regulate chromatin compaction involving the reversible formation of higher order structures. The compaction state of chromatin varies between interphase and mitosis and is also subject to rapid and reversible change upon ATP depletion/repletion. In this study we have investigated mechanisms that may be involved in promoting the hyper-condensation of chromatin when ATP levels are depleted by treating cells with sodium azide and 2-deoxyglucose. Chromatin conformation was analysed in both live and permeabilised HeLa cells using FLIM-FRET, high resolution fluorescence microscopy and by electron spectroscopic imaging microscopy. We show that chromatin compaction following ATP depletion is not caused by loss of transcription activity and that it can occur at a similar level in both interphase and mitotic cells. Analysis of both live and permeabilised HeLa cells shows that chromatin conformation within nuclei is strongly influenced by the levels of divalent cations, including calcium and magnesium. While ATP depletion results in an increase in the level of unbound calcium, chromatin condensation still occurs even in the presence of a calcium chelator. Chromatin compaction is shown to be strongly affected by small changes in the levels of polyamines, including spermine and spermidine. The data are consistent with a model in which the increased intracellular pool of polyamines and divalent cations, resulting from depletion of ATP, bind to DNA and contribute to the large scale hyper-compaction of chromatin by a charge neutralisation mechanism.