Personal protective equipment training & lived experience for healthcare staff during COVID-19

Objectives

To describe the lived experience of healthcare staff during the Coronavirus Disease 2019 (COVID-19) pandemic relating to the use of personal protective equipment (PPE) and investigate risks associated with PPE use, error mitigation and acceptability of mindfulness incorporation into PPE practice.

Methods

A qualitative human factors' study at two Irish hospitals occurred in late 2020. Data was collected by semi-structured interview and included role description, pre-COVID-19 PPE experience, the impact of COVID-19 on lived experience, risks associated with PPE use, contributory factors to errors, error mitigation strategies and acceptability of incorporating mindfulness into PPE practice.

Results

Of 45 participants, 23 of whom were nursing staff (51%), 34 (76%) had previously worn PPE and 25 (56%) used a buddy system. COVID-19 lived experience impacted most on social life/home-work interface (n=36, 80%). Nineteen staff (42%) described mental health impacts. The most cited risk concerned 'knowledge of procedures' (n=18, 40%). Contributory factors to PPE errors included time (n=15, 43%) and staffing pressures (n=10, 29%). Mitigation interventions included training/education (n=12, 40%). The majority (n=35, 78%) supported mindfulness integration into PPE practice.

Conclusions

PPE training should address healthcare staff lived experiences and consider incorporation of mindfulness and key organisational factors contributing to safety.

Gut-derived GIP activates central Rap1 to impair neural leptin sensitivity during overnutrition

Nutrient excess, a major driver of obesity, diminishes hypothalamic responses to exogenously administered leptin, a critical hormone of energy balance. Here, we aimed to identify a physiological signal that arises from excess caloric intake and negatively controls hypothalamic leptin action. We found that deficiency of the gastric inhibitory polypeptide receptor (Gipr) for the gut-derived incretin hormone GIP protected against diet-induced neural leptin resistance. Furthermore, a centrally administered antibody that neutralizes GIPR had remarkable antiobesity effects in diet-induced obese mice, including reduced body weight and adiposity, and a decreased hypothalamic level of SOCS3, an inhibitor of leptin actions. In contrast, centrally administered GIP diminished hypothalamic sensitivity to leptin and increased hypothalamic levels of Socs3. Finally, we show that GIP increased the active form of the small GTPase Rap1 in the brain and that its activation was required for the central actions of GIP. Altogether, our results identify GIPR/Rap1 signaling in the brain as a molecular pathway linking overnutrition to the control of neural leptin actions.

A GLP-1:CCK fusion peptide harnesses the synergistic effects on metabolism of CCK-1 and GLP-1 receptor agonism in mice

Combination approaches for the treatment of metabolic diseases such as obesity and diabetes are becoming increasingly relevant. Co-administration of a glucagon-like peptide-1 receptor (GLP-1R) agonist with a cholecystokinin receptor-1 (CCKR1) agonist exert synergistic effects on weight loss in obese rodents. Here, we report on the effects of a novel fusion peptide (C2816) comprised of a stabilized GLP-1R agonist, AC3174, and a CCKR1-selective agonist, AC170222. C2816 was constructed such that AC3174 was linked to the N-terminus of AC170222, thus preserving the C-terminal amide of the CCK moiety. In functional in vitro assays C2816 retained full agonism at GLP-1R and CCKR1 at lower potency compared to parent molecules, whereas a previously reported fusion peptide in the opposite orientation, (pGlu-Gln)-CCK-8/exendin-4, exhibited no activity at either receptor. Acutely, in vivo, C2816 increased cFos in key central nuclei relevant to feeding behavior, and reduced food intake in wildtype (WT), but less so in GLP-1R-deficient (GLP-1RKO), mice. In sub-chronic studies in diet-induced obese (DIO) mice, C2816 exerted superior reduction in body weight compared to co-administration of AC3174 and AC170222 albeit at a higher molar dose. These data suggest that the synergistic pharmacological effects of GLP-1 and CCK pathways can be harnessed in a single therapeutic peptide.

Deletion of hepatic carbohydrate response element binding protein (ChREBP) impairs glucose homeostasis and hepatic insulin sensitivity in mice

OBJECTIVE

Carbohydrate response element binding protein (ChREBP) is a transcription factor that responds to glucose and activates genes involved in the glycolytic and lipogenic pathways. Recent studies have linked adipose ChREBP to insulin sensitivity in mice. However, while ChREBP is most highly expressed in the liver, the effect of hepatic ChREBP on insulin sensitivity remains unknown. To clarify the importance of hepatic ChREBP on glucose homeostasis, we have generated a knockout mouse model that lacks this protein specifically in the liver (Liver-ChREBP KO).

METHODS

Using Liver-ChREBP KO mice, we investigated whether hepatic ChREBP deletion influences insulin sensitivity, glucose homeostasis and the development of hepatic steatosis utilizing various dietary stressors. Furthermore, we determined gene expression changes in response to fasted and fed states in liver, white, and brown adipose tissues.

RESULTS

Liver-ChREBP KO mice had impaired insulin sensitivity as indicated by reduced glucose infusion to maintain euglycemia during hyperinsulinemic-euglycemic clamps on both chow (25% lower) and high-fat diet (33% lower) (p < 0.05). This corresponded with attenuated suppression of hepatic glucose production. Although Liver-ChREBP KO mice were protected against carbohydrate-induced hepatic steatosis, they displayed worsened glucose tolerance. Liver-ChREBP KO mice did not show the expected gene expression changes in liver in response to fasted and fed states. Interestingly, hepatic ChREBP deletion also resulted in gene expression changes in white and brown adipose tissues, suggesting inter-tissue communication. This included an almost complete abolition of BAT ChREBPβ induction in the fed state (0.15-fold) (p = 0.015) along with reduced lipogenic genes. In contrast, WAT showed inappropriate increases in lipogenic genes in the fasted state along with increased PEPCK1 in both fasted (3.4-fold) and fed (5.1-fold) states (p < 0.0001).

CONCLUSIONS

Overall, hepatic ChREBP is protective in regards to hepatic insulin sensitivity and whole body glucose homeostasis. Hepatic ChREBP action can influence other peripheral tissues and is likely essential in coordinating the body's response to different feeding states.

Neurturin and a GLP-1 Analogue Act Synergistically to Alleviate Diabetes in Zucker Diabetic Fatty Rats

Neurturin (NRTN), a member of the glial-derived neurotrophic factor family, was identified from an embryonic chicken pancreatic cDNA library in a screen for secreted factors. In this study, we assessed the potential antidiabetic activities of NRTN relative to liraglutide, a glucagon-like peptide 1 receptor agonist, in Zucker diabetic fatty (ZDF) rats. Subcutaneous administration of NRTN to 8-week-old male ZDF rats prevented the development of hyperglycemia and improved metabolic parameters similar to liraglutide. NRTN treatment increased pancreatic insulin content and β-cell mass and prevented deterioration of islet organization. However, unlike liraglutide-treated rats, NRTN-mediated improvements were not associated with reduced body weight or food intake. Acute NRTN treatment did not activate c-Fos expression in key feeding behavior and metabolic centers in ZDF rat brain or directly enhance glucose-stimulated insulin secretion from pancreatic β-cells. Treating 10-week-old ZDF rats with sustained hyperglycemia with liraglutide resulted in some alleviation of hyperglycemia, whereas NRTN was not as effective despite improving plasma lipids and fasting glucose levels. Interestingly, coadministration of NRTN and liraglutide normalized hyperglycemia and other metabolic parameters, demonstrating that combining therapies with distinct mechanism(s) can alleviate advanced diabetes. This emphasizes that therapeutic combinations can be more effective to manage diabetes in individuals with uncontrolled hyperglycemia.

Dietary Macronutrient Composition Directs ChREBP Isoform Expression and Glucose Metabolism in Mice

Carbohydrate response element binding protein (ChREBP) is a lipogenic transcription factor that is thought to be involved in the development of hepatic steatosis and insulin resistance. Increased ChREBP expression in liver results in increased hepatic steatosis, and the isoform ChREBPβ in adipose tissue can predict insulin sensitivity in obese humans. As ChREBP is activated by glucose, it was postulated that the composition of diet would regulate ChREBP isoform expression in metabolically relevant tissues.

We compared the effects of diets with high complex carbohydrate, high fat, or a normal chow on ChREBP expression and metabolic parameters in C57BL/6 mice. We found that diets high in fat decrease ChREBP expression in adipose tissue, but isocaloric diets high in carbohydrate have no effect. Interestingly, this decrease in adipose ChREBP was associated with increased inflammatory markers. In the same animals a high carbohydrate diet induced a robust increase in hepatic ChREBPβ expression (≈2-fold; p = 0.0002), but little detectable change in the more abundant ChREBPα transcript. This change was accompanied by increased expression of target genes liver pyruvate kinase (p<0.0001), acetyl-CoA carboxylase (p = 0.0191) and stearoyl-CoA desaturase-1 (p = 0.0045). This increase in ChREBP expression was associated with increased hepatic steatosis, despite no changes in body weight or body fat when compared to chow-fed mice. Unexpectedly, mice fed a high carbohydrate diet displayed enhanced sensitivity to exogenous insulin, despite having mild glucose intolerance and increased liver steatosis.

In summary, we have shown the composition of diet can selectively regulate ChREBP isoform expression in a tissue specific manner. Furthermore, we have shown a high complex carbohydrate diet selectively increases hepatic ChREBPβ expression, which associates with hepatic steatosis but not insulin resistance. In contrast, a high fat diet reduces adipose ChREBP, which associates with inflammation and insulin resistance.

Localized axillary milia en plaque: a rare cutaneous case presentation of systemic amyloidosis

Systemic AL amyloidosis is known to be associated with plasma cell dyscrasias, including multiple myeloma. The cutaneous manifestations of systemic AL amyloidosis are varied, but typically include waxy plaques or subcutaneous nodules. We report a woman who presented with bilateral eruptions of hyperpigmented plaques in her axillae, which were diagnosed as milia en plaque. She had a history of multiple myeloma, for which she was under the care of a haematologist. This is the first documented case, to our knowledge, of an eruption in the axillae being milia en plaque.

Effect of intracerebroventricular injection of TiO2 nanoparticles on complex behaviour in the rat

There are no data available on the behavioural effects of centrally administered nanoparticles in freely moving intact mammals. Consequently, in the current study male Sprague-Dawley rats were trained to respond under an alternating-lever cyclic-ratio (ALCR) schedule of food reinforcement. Under this schedule, ascending and descending sequences of fixed-ratio (FR) lever press requirements for food reinforcement were presented over six cycles, with each discrete FR component completed on the alternate lever to the previous component. The final version of the schedule was comprised of an ascending followed by a descending sequence of the ratio values 2, 6, 12, 20, 30, 42 and 56, repeated over six cycles. When the rats were able to complete this version of the ALCR schedule in 40 min, each was implanted with a permanently indwelling ICV cannula aimed at the lateral ventricle of the brain, and allowed to recover for 7 days. On the first day of the experiment, all rats were injected with either titanium dioxide (TiO2, 9 nm, stabilised with gallic acid, 10 microl volume, 2 mg/ml) nanoparticles, or 10 microl saline (control). Two-hours after the ICV injections, the behaviour of all rats was measured using the ALCR schedule, and their behaviour was also measured (no ICV injection) for the next 7 days. Under the ALCR schedule, the number of lever-switching errors and incorrect lever perseverations significantly increased in the TiO2 group (p < 0.05). Other parameters of the ALCR schedule (RRRs and PRPs), which indicate the induction of malaise or general motor retardation, were not altered following ICV TiO2 injection. The findings of the current study indicate that central administration of TiO2 nanoparticles induced behavioural deterioration in freely moving intact animals, that the induced behavioural deterioration was a result of central rather than peripheral outcomes, and that this effect was chronic rather than acute.

Frequent mutations in SH2D1A (XLP) in males presenting with high-grade mature B-cell neoplasms

X-linked lymphoproliferative syndrome (XLP) is caused by mutations in SH2D1A, and is associated with overwhelming infectious mononucleosis, aplastic anemia, hypogammaglobulinemia, and B-cell lymphomas. However, the frequency of SH2D1A mutations in males who present with B NHL is unknown. Five cases of XLP were diagnosed among 158 males presenting with B NHL (approximately 3.2%). Four of the patients had two episodes of B NHL and one had a single episode of B NHL followed by aggressive infectious mononucleosis. Prospective screening for XLP in males with B-cell lymphoma at the time of initial diagnosis should be considered.

Vascular risk factors and cognitive impairment in a stroke-free cohort

OBJECTIVE

To examine vascular risk factors, as measured by the Framingham Stroke Risk Profile (FSRP), to predict incident cognitive impairment in a large, national sample of black and white adults age 45 years and older.

METHODS

Participants included subjects without stroke at baseline from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study with at least 2 cognitive function assessments during the follow-up (n = 23,752). Incident cognitive impairment was defined as decline from a baseline score of 5 or 6 (of possible 6 points) to the most recent follow-up score of 4 or less on the Six-item Screener (SIS). Subjects with suspected stroke during follow-up were censored.

RESULTS

During a mean follow-up of 4.1 years, 1,907 participants met criteria for incident cognitive impairment. Baseline FSRP score was associated with incident cognitive impairment. An adjusted model revealed that male sex (odds ratio [OR] = 1.59, 95% confidence interval [CI] 1.43-1.77), black race (OR = 2.09, 95% CI 1.88-2.35), less education (less than high school graduate vs college graduate, OR = 2.21, 95% CI 1.88-2.60), older age (10-year increments, OR = 2.11, per 10-year increase in age, 95% CI 2.05-2.18), and presence of left ventricular hypertrophy (LVH, OR = 1.29, 95% CI 1.06-1.58) were related to development of cognitive impairment. When LVH was excluded from the model, elevated systolic blood pressure was related to incident cognitive impairment.

CONCLUSIONS

Total FSRP score, elevated blood pressure, and LVH predict development of clinically significant cognitive dysfunction. Prevention and treatment of high blood pressure may be effective in preserving cognitive health.

Inpatient staff perceptions in providing care to individuals with co-occurring mental health problems and illicit substance use

ACCESSIBLE SUMMARY

This paper reports on a piece of research which is summarized below. • This research explored how mental health inpatient staff, (including nurses, doctors and other professional disciplines) experience caring for patients who both have mental health problems and who use illicit drugs. (Illicit drugs are illegal drugs which incur a criminal prosecution for possession and/or use). The results of the study were gathered from questionnaires and interviews which asked staff about their viewpoints and experiences. • The questionnaire results included a section which measured staff attitude towards patients who use illicit drugs and who have mental health problems. Staff who had received training in how to work with people with these problems were found to have a less negative attitude towards these patients. The length of time staff members had worked in their posts or had worked in a particular setting did not have any effect on their attitude. For example, their attitude was not more or less negative towards patients with these problems. • Ten members of staff were interviewed to find out more in-depth information about their viewpoints and experiences. Overall, these staff members reported a lack of training, difficulty in accessing support and problematic issues within the teams they worked. • This paper highlights the importance of training to support staff in working with mental health patients who use illicit drugs; and how this affects staff attitude positively towards patients with these problems.

ABSTRACT

The extent of illicit substance use within inpatient mental health settings is becoming a major cause of concern. This poses growing challenges not only for the management of inpatient units, but also for providing continuity of care. Service users with co-occurring substance use are more likely to disengage from services. The process of engagement can be hindered by negative attitudes of staff. This study aimed to identify and explore multidisciplinary staff attitudes and experiences in caring for inpatients with co-occurring ill-mental health problems and illicit substance use. A questionnaire incorporating the Drug and Drugs Problems Perceptions Questionnaire (DDPPQ) was used with a non-probability sample of 84 multidisciplinary staff working on nine mental health units. Semi-structured interviews were then carried out with 10 members of staff. Overall, respondents reported: lack of training; difficulty in accessing support structures; and problematic issues with multidisciplinary decision making and processes. The DDPPQ results showed that staff who had received training held less negative attitudes towards illicit substance users regardless of their length of clinical work experience or type of work setting. Recommendations are made about the importance of training and staff support for the development of less negative attitudes towards this client group.

A minimally hypomorphic mutation in Btk resulting in reduced B cell numbers but no clinical disease

Reduced B cell numbers and a mutation in Btk are considered sufficient to make the diagnosis of X-linked agammaglobulinaemia. In the process of conducting family studies, we identified a 58-year-old healthy man with an amino acid substitution, Y418H, in the adenosine-5'-triphosphate binding site of Btk. Immunofluorescence studies showed that this man had 0.85% CD19+ B cells (normal 4-18%) in the peripheral circulation and his monocytes were positive for Btk. He had borderline low serum immunoglobulins but normal titres to tetanus toxoid and multiple pneumococcal serotypes. To determine the functional consequences of the amino acid substitution, a Btk- chicken B cell line, DT40, was transfected with expression vectors producing wild-type Btk or Y418H Btk. The transfected cells were stimulated with anti-IgM and calcium flux and inositol triphosphate (IP3) production were measured. Cells bearing the mutant protein demonstrated consistently a 15-20% decrease in both calcium flux and IP3 production. These findings indicate that even a modest decrease in Btk function can impair B cell proliferation or survival. However, a mutation in Btk and reduced numbers of B cells are not always associated with clinical disease.

The growing incidence of cancer: role of lifestyle and screening detection (Review)

The increasing incidence of a variety of cancers after the Second World War confronts scientists with the question of their origin. In Western countries, expansion and ageing of the population, as well as progress in cancer detection using new diagnostic and screening tests cannot fully account for the observed growing incidence of cancer. Our hypothesis is that environmental factors play a more important role in cancer genesis than it is usually agreed: i) over the last 2-3 decades, alcohol consumption and tobacco smoking in men have significantly decreased; ii) obesity is increasing in many countries, but the growing incidence of cancer also concerns cancers not related to obesity nor to other lifestyle-related factors; iii) there is evidence that the environment has changed over the same time scale as the recent rise in cancer incidence, and that this change included the accumulation of many new carcinogenic factors in the environment; iv) genetic susceptibility to cancer due to genetic polymorphism cannot have changed over one generation and actually favours the role of exogenous factors through gene-environment interactions; v) age is not the unique factor to be considered since the rising incidence of cancers is seen across all age categories, including children; vi) the fetus is specifically vulnerable to exogenous factors. A fetal exposure during a critical window period may explain why current epidemiological studies may be negative in adults. We therefore propose that the involuntary exposure to many carcinogens in the environment contributes to the rising trend in cancer incidence.

A possible bichromatid mutation in a male gamete giving rise to a female mosaic for two different mutations in the X-linked gene WAS

In genetic disorders caused by point mutations or small frameshift mutations, affected members of the same family are expected to have the same mutation in the causative gene. We have recently evaluated a family in which this was not the case. Maternal cousins with Wiskott-Aldrich syndrome (WAS; MIM 301000) had two different but contiguous single base pair deletions in WAS. The proband had an A deletion in codon 242 in exon 7 of WAS; his two cousins had a C deletion in codon 241. The mother of the proband was heterozygous for the A deletion allele, but her three sisters, including the mother of the affected cousins, were heterozygous for the C deletion. Both deletions occurred on the haplotype from the unaffected maternal great-grandfather. The maternal grandmother, who was a carrier of WAS, based on a non-random pattern of X chromosome inactivation in T cells, was mosaic for both deletions. These findings are most consistent with the mutations originating in a male gamete with different mutations on the two strands of DNA, a bichromatid mutation.

Neocortical synaptic bouton number is maintained despite robust amyloid deposition in APP23 transgenic mice

Major pathological findings in Alzheimer's disease (AD) brain include the deposition of amyloid-beta and synapse loss. Synaptic loss has been shown to correlate with the cognitive decline in AD patients, but the relationship between cerebral amyloidosis and synapse loss is complicated by the presence of neurofibrillary tangles and other lesions in AD brain. With the use of the APP23 transgenic mouse model that overexpresses human amyloid precursor protein (APP) with the Swedish double mutation, we investigated whether the development of cortical amyloid deposition was accompanied by synaptic bouton loss. With stereological methods, we show that despite robust age-related cortical amyloid deposition with associated synaptic degeneration, the total number of cortical synaptophysin-positive presynaptic terminals is not changed in 24-month-old animals compared with 3-, 8-, and 15-month-old APP23 mice. Wild-type mice also do not show an age-related loss of presynaptic boutons in the neocortex and are not significantly different from APP23 mice. Synaptophysin Western blotting revealed no significant difference between APP23 mice and wild-type controls at 3 and 25 months of age. Our results suggest that cerebral amyloidosis is not sufficient to account for the global synapse loss in AD. Alternatively, a putative trophic effect of APP may prevent, compensate, or delay a loss of synapses in this mouse model.

Immune responses against Abeta1-42 in HLA class II transgenic mice: implications for Abeta1-42 immune-mediated therapies

We have investigated whether polymorphic differences in the major histocompatibility complex (MHC) class II molecules influence humoral and cellular immune responses against Abeta1-42. To analyze the effects of mouse MHC class II and tolerance effects of overexpression of human APP in mice, we immunized Tg2576 and non-transgenic littermates bred into two different MHC backgrounds with Abeta1-42 and compared both B and T cell responses. We found that in the presence of the mouse C57BL/6 background, both B and T cell responses against Abeta1-42 were significantly suppressed. To directly test the contribution of human MHC class II, we immunized various human HLA class II transgenic (TG) mice with Abeta1-42 and analyzed anti-Abeta immune responses. HLA-DR3 and HLA-DQ8 TG mice generated modest B and T cell responses against Abeta1-42. The presence of HLA-DR3/DQ8 in double TG mice enhanced the overall immune response against Abeta1-42. In contrast, HLA-DR4 TG mice mounted strong T cell responses but failed to generate high titer antibody responses against Abeta1-42, whereas, the HLA-DQ6 TG mice were not able to mount significant B or T cell responses against Abeta1-42. These studies in mice suggest that the presence of certain MHC class II molecules or combinations of class II molecules can potentially influence the overall immune response against Abeta1-42.

Amyloid-beta immunization effectively reduces amyloid deposition in FcRgamma-/- knock-out mice

Direct immunization with amyloid beta protein (Abeta) and passive transfer of anti-Abeta antibodies reduce Abeta accumulation and attenuate cognitive deficits in transgenic models of Alzheimer's disease (AD). The reduction in Abeta deposition has been proposed to involve microglial phagocytosis of Abeta immune complexes via Fc receptors (FcRs). We have examined the efficacy of Abeta immunization in amyloid precursor protein (APP) transgenic mice crossed into FcR-gamma chain knock-out mice (FcRgamma-/-). As might be expected from previous studies on macrophages, phagocytosis of Abeta immune complexes via FcR was completely impaired in microglia cells isolated from FcRgamma-/- mice. Thus, we immunized APP Tg2576 transgenic mice that were crossed in the FcRgamma-/- background with Abeta1-42 and then analyzed the effect on Abeta accumulation. In APP Tg2576 transgenic mice crossed to FcRgamma-/-, Abeta1-42 immunization significantly attenuated Abeta deposition, as assessed by both biochemical and immunohistological methods. The reduction in Abeta accumulation was equivalent to the reduction in deposition seen in Abeta1-42 immunized, age-matched, FcR-sufficient Tg2576 mice. We conclude that after Abeta immunization, the effects of anti-Abeta antibodies on Abeta deposition in APP Tg2576 transgenic mice are not dependent on FcR-mediated phagocytic events.

Comparison of intraoperative dosimetric implant representation with postimplant dosimetry in patients receiving prostate brachytherapy

PURPOSE

To compare the results of intraoperative dosimetry with those of CT-based postimplant dosimetry in patients undergoing prostate seed implantation.

METHODS AND MATERIALS

Seventy-seven patients with T1-T3 prostate cancer received an ultrasound-guided permanent seed implant (36 received (125)I, 7 (103)Pd, and 34 a partial (103)Pd implant plus external beam radiation therapy). The implantation was augmented with an intraoperative dosimetric planning system. After the peripheral needles were placed, 5-mm axial images were acquired into the treatment planning system. Soft tissue structures (prostate, urethra, and rectum) were contoured, and exact needle positions were registered. Seeds were placed with an applicator, and their positions were entered into the planning system. The dose distributions for the implant were calculated after interior needle and seed placement. Postimplant dosimetry was performed 1 month later on the basis of CT imaging. Prostate and urethral doses were compared, by using paired t tests, for the real-time dosimetry in the operating room (OR) and the postimplant dosimetry.

RESULTS

The mean preimplant prostate volume was 39.8 cm(3), the postneedle planning volume was 41.5 cm(3) (p<0.001), and the 1-month CT volume was 43.6 cm(3) (p<0.001). The mean difference between the OR dose received by 90% of the prostate (D(90)) and the CT D(90) was 3.4% (95% confidence interval, 2.5-6.6%; p=0.034). The mean dose to 30% of the urethra was 120% of prescription in the OR and 138% on CT. The mean difference was 18% (95% confidence interval, 13-24%; p<0.001).

CONCLUSIONS

Although small differences exist between the OR and CT dosimetry results, these data suggest that this intraoperative implant dosimetric representation system provides a close match to the actual delivered doses. These data support the use of this system to modify the implant during surgery to achieve more consistent dosimetry results.

Age and gender effects on microglia and astrocyte numbers in brains of mice

The morphological changes that occur during normal brain aging are not well understood. This study used modern stereology to assess the effects of age and gender on total numbers of astrocytes and microglia in the hippocampal formation in C57Bl/6NNIA (B6) mice. Astrocytes and microglia were visualized using immunocytochemistry for glial fibrillary acidic protein (GFAP) and complement receptor 3 (Mac-1), respectively, and numbers of each cell type in dentate gyrus (DG) and CA1 regions were estimated using the optical fractionator method. The results reveal significantly greater ( approximately 20%) numbers of microglia and astrocytes in aged females compared to young female B6 mice. We also report that on average female B6 mice have 25-40% more astrocytes and microglia in DG and CA1 regions than age-matched male C57Bl/6J mice. Since astrocytes and microglia are thought to be targets of gonadal hormones, the effects of sex hormones and reproductive aging may be responsible for these findings.

Identification and analysis of dihydrofolate reductase alleles from Plasmodium falciparum present at low frequency in polyclonal patient samples

As resistance to chloroquine spreads in sub-Saharan Africa, pyrimethamine plus sulfadoxine (PSD) is increasingly used as a first-line treatment for falciparum malaria. Populations of Plasmodium falciparum (Pf) resistant to PSD have been selected quickly in other regions. The resistance is strongly correlated with point mutations in dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS), the two targets of the drug. It is critical to identify drug-resistant Pf-DHFR alleles that are present at a low frequency in these populations since alleles that confer drug resistance will be quickly selected by PSD use. It is difficult to identify these rare alleles by standard molecular techniques. We have designed a yeast expression system that facilitates the identification and rapid analysis of Pf-DHFR alleles that confer PSD resistance, even when they are present at very low frequency in polyclonal patient samples. We analyzed samples from patients in Kilifi, Kenya collected between 1992 and 1995. We determined the prevalence of the drug-sensitive and drug-resistant alleles in patient samples analyzed in parallel by an allele-specific enzyme digestion (ASED) assay. We identified a pyrimethamine-resistant allele (S108N) present at a frequency of < 1% in a sample that was scored as only S108 by ASED. In addition, a novel pyrimethamine-resistant allele (1164M) was isolated twice, once each from two different patient samples. This approach will allow determination of the prevalence of Pf-DHFR alleles that confer pyrimethamine resistance in particular regions, and the rapid identification of novel alleles that confer drug resistance.

Fatigue in children and adolescents with cancer

Fatigue is a common symptom found in the adult oncology literature. However, little is known about its occurrence, causes, conceptual and operational definitions, and effective interventions in children and adolescents with cancer. The purpose of this study was to define and describe fatigue experienced by children and adolescents receiving treatment for cancer. A focus group approach was used to reveal the contextual understanding of fatigue through discussions. Eleven focus groups were convened during a 2-month period at two major children's cancer centers. Twenty-nine children participated in the focus groups: 14 were 7 to 12 years of age and 15 were 13 to 16 years of age. Focus groups were held separately for each age group, lasted from 30 to 45 minutes, and were audiotaped. The audiotapes were transcribed verbatim, and Ethnograph software was used to number the data to sort and code the information. Researchers at both study sites coded the data independently within the context of the unit of analyses, which, in this study, were the study questions. Codes and descriptions were developed for the definitions of fatigue, causes of fatigue, and what helps. Eight codes emerged from the children groups and 12 from the adolescent groups to define fatigue. Six codes were developed from the children groups and 12 from the adolescent groups to describe causes of fatigue. Three codes from the children groups and eight from the adolescent groups described what helps. This study is the first to evaluate fatigue as a symptom in children and adolescents with cancer. Findings from this study will provide the foundation for developing a conceptual model for cancer-related fatigue in children and adolescents.

Effect of propylthiouracil treatment during prenatal and early postnatal development on the neocortex of rat pups

The effects of a pre- and postnatal hypothyroid environment on the development of the neocortex have been determined. Rats were treated with propylthiouracil (PTU) with or without thyroid hormone supplementation during pregnancy and throughout the early development of the pups. The Cavalieri method was used to provide an estimate of the volume of the neocortex, and a combination of the Cavalieri method and the 'disector' particle-counting method provided an unbiased estimate of the numbers of glia and neurons in the neocortex. In pups from non-treated rats the mean volume of the neocortex increased from 31.3 mm3 at 5 days postnatally to 191.5 mm3 at 20 days and then remained constant to day 48. Similarly, the mean number of glial cells increased from 5.2 x 10(6) at day 5 to 12.0 x 10(6) on day 20 and then remained constant to day 48. The mean number of neurons in the neocortex in the control condition was constant at about 14.6 x 10(6) from day 5 to day 48. PTU treatment during pregnancy and postnatal development significantly decreased the mean volume of the neocortex at all of the stages studied, for example from 31.3 to 23.3 mm3 (p less than 0.001) on day 5 and from 191.5 to 155.0 mm3 (p less than 0.001) on day 20. Supplementation with thyroxine (T4) or tri-iodothyronine partially reversed this at certain stages. For example, the mean volume of the neocortex at 48 days was 197.5 mm3 in control rats, 118.1 mm3 in PTU-treated rats and 169.3 mm3 in PTU-treated rats supplemented with T4. Within the neocortex, the volume of the neuropile was more severely affected than was the volume of the neuron cell bodies.(ABSTRACT TRUNCATED AT 250 WORDS)

Unbiased estimation of particle density in the tandem scanning reflected light microscope

The tandem scanning reflected light microscope has the property of being able to obtain information from 'inside' solid objects by taking a thin optical section at the focal plane of the objective lens. This plane can be focused up and down through the specimen. We describe an unbiased 3-D counting rule for the TSRLM, which is applied to the estimation of osteocyte lacunar density in whole bone. This is shown to be an extremely efficient way of making such an estimate. Further possibilities for the application of the microscope in the field of stereology are discussed.

Further experience with regional radiofrequency hyperthermia and cytotoxic chemotherapy for unresectable hepatic neoplasia

The authors report on 178 patients with unresectable hepatic tumors who have been treated with 1 to 25 (median, 6) courses of radiofrequency hyperthermia (RFHT) and chemotherapy. In 137 patients, the hepatic tumors consisted of metastases from colorectal adenocarcinomas. For patients who had no previous therapy and who had colorectal metastases with no extraheptic disease, cumulative survival at 52 weeks' follow-up was 80.5% and partial tumor regression was seen in 78.4%. Among the 69 patients who previously had conventional treatment for their hepatic disease, partial regression was seen in 43.5%. We are no longer monitoring tumor core temperature routinely, as the invasive methods currently in use yield irreproducible results; the risks to the patient cannot be justified in view of the questionable relevance of the data obtained. A prospective randomized study of systemic chemotherapy with or without RFHT in patients with colorectal hepatic metastases is in progress.

Palliation of advanced head and neck cancer with radiofrequency hyperthermia and cytotoxic chemotherapy

Fourteen patients with recurrent malignant tumours of the head and neck were treated with radiofrequency hyperthermia and chemotherapy after conventional therapy had failed. After 2 to 11 treatment courses and a follow-up of 30 weeks, the neoplasms in three patients had completely regressed and one had a partial response. Of eight patients who died, two had partial responses initially; a third patient died of complications relating to surgical resection of the tumour after a partial response. Three of five patients whose tumours were unresponsive to methotrexate responded when this drug was given with radiofrequency hyperthermia. There were seven minor skin burns in six patients. Further studies of radiofrequency hyperthermia and chemotherapy for palliation of head and neck cancer are planned.