Preoperative breast imaging and histopathological findings in chest contouring surgery on transmen

BACKGROUND

Chest contouring is the most common surgical procedure transmen receive. Only a few articles discuss the importance of preoperative imaging and postoperative histopathological analysis of excised breast tissue. We studied the findings of preoperative breast imaging and the results of postoperative histopathological analysis in a clinical setting.

MATERIALS AND METHODS

Data from 220 patients were collected retrospectively from 2005 to 2018. Preoperative imaging modalities and their findings were recorded and classified according to the American College of Radiology Breast Imaging Reporting and Data System. The histopathological findings in breast specimens were categorized based on the World Health Organization Classification of Breast Tumors (5th edition).

RESULTS

Preoperative imaging was performed in 133 (60.5%) patients. Patients in the ultrasound-only group were younger (mean age 22.8) than the other groups (mammogram (MGR) 37 years and MGR+US 35.5 years). Preoperative imaging results were normal in 131 (98.5%) patients. Two patients needed further evaluation. Histopathological results were available on 206 (93.6%) patients. The most common histopathological findings were fibrosis (67.5%), atrophy (34.3%), and chronic mastopathy (14.5%). There were no high-risk or malignant findings.

CONCLUSIONS

The need for further examinations based on routine preoperative imaging was low (1.5%). Therefore, more individualized patient selection for preoperative imaging is justified. There were no high-risk or malignant findings in histopathological analysis, and the occurrence of benign findings was similar to that reported in previous studies. Despite our findings, based on current knowledge, histopathological examination of excised breast tissue can still be recommended. Therefore, future studies are needed to define clear guidelines.

Validation of the BODY-Q Chest module in Finnish trans men undergoing chest wall masculinization

BACKGROUND AND OBJECTIVE

The aim of gender affirmation surgery is to ease gender dysphoria. In transgender men, chest wall masculinization is the most common gender affirmation surgery. The BODY-Q Chest module is currently the only instrument developed to measure health-related quality of life (HRQL) in men undergoing chest wall surgery. Linguistic validation and cultural adaption to Finnish were performed previously. The study aims to validate the BODY-Q Chest module in transgender men who have undergone surgical chest wall masculinization.

METHODS

All transgender patients who underwent chest wall masculinization at Helsinki University Hospital between 2005 and 2018 were invited to the study. The BODY-Q Chest module comprises two scales-chest and nipple. Data were obtained using the BODY-Q Chest module, the 15D questionnaire, and specifically targeted items designed by the authors. The statistical analyses were conducted to exclude selection bias, evaluate validity of the instrument, and compare it to other instruments.

RESULTS

Of the 220 patients invited, 123 participated in the survey (response rate 56%). Ceiling effects were observed with 18.9% and 20.5% scoring maximum points. Cronbach's alpha was 0.92 and 0.88 for the chest and nipple scales, respectively. In exploratory factor analysis, both scales loaded to one factor confirming unidimensionality. Correlation with the generic 15D questionnaire was low.

CONCLUSIONS

The BODY-Q Chest module provides valid scores with sufficient consistency and reliability when measuring HRQL in transgender men undergoing chest wall masculinization. Moreover, it offers specificity that existing or generic instruments cannot provide. Ceiling effect was expected due to the postoperative status of participants.

Prolonged injury symptoms and later visits to psychiatric care after mild traumatic brain injury in school-age

OBJECTIVE

To investigate demographic and pre-injury factors in Finnish school-aged children admitted to pediatric neurology services after mild traumatic brain injury (mTBI). The relation of these factors to prolonged injury symptoms and later visits into psychiatric care was assessed.

METHODS

Demographic information, pre-injury learning status, and neuropsychological test results of 120 patients aged 7-16 years were retrospectively collected from the hospital medical records. Data were compared with self- or parent-reported injury symptoms at 1-3 months post-injury and later visits to psychiatric care.

RESULTS

According to medical records, 14.2% of the children with mTBI had a diagnosed neurobehavioral or psychiatric condition pre-injury. Additionally, 53.3% of the children had some neurobehavioral or psychiatric concerns or traits prior to the injury. Over half (56.7%) of the children studied were symptomatic at 1-3 months following the injury. Female gender and presence of prolonged symptoms were predictive for later visit into psychiatric care.

CONCLUSIONS

Pre-injury neurobehavioral or psychiatric problems may predict prolonged injury symptoms following pediatric mTBI. In this retrospective patient series, prolonged symptoms and female gender seem to predict the need for later psychiatric care. Monitoring the recovery of children with mTBI and pre-injury risk factors is important for timely interventions.

Medical surveillance for occupational asthma-how are cases detected?

Background

In Finland, medical surveillance, including spirometry, is periodically performed for workers who are exposed to agents capable of causing occupational asthma (OA). Although it has been shown that surveillance can detect OA at an early stage, few studies have assessed its benefits or the role of surveillance spirometry.

Aims

To assess the role of surveillance and spirometry in detecting OA and to evaluate the quality of spirometry.

Methods

We retrospectively reviewed the medical files of patients in health surveillance programmes who were diagnosed with sensitizer-induced OA at the Finnish Institute of Occupational Health in 2012‒14. We collected information on work exposure, respiratory symptoms, healthcare visits that initiated the diagnostic process, first spirometry and other diagnostic tests.

Results

Sixty files were reviewed. Medical surveillance detected 11 cases (18%) and 49 cases (82%) were detected at doctors' appointments that were not related to surveillance. The median delay from the onset of asthma symptoms to diagnosis was 2.2 years. Delay did not differ between these groups. No cases were detected on the basis of abnormal spirometry without respiratory symptoms. However, five patients (8%) initially reported solely work-related rhinitis symptoms. Spirometry was normal in half of the cases and quality criteria were fulfilled in 86% of the tests.

Conclusions

Fewer than one in five OA cases were detected through medical surveillance. Investigations were initiated by respiratory symptoms. No asymptomatic worker was referred because of abnormal spirometry. Our results highlight the importance of work-related nasal symptoms in detecting OA.

End-of-life care of patients with idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis (IPF) is a progressive disease with median survival from 2 to 7 years. Palliative care is an important part of patients´ care as lung transplantation is not an option for the majority of patients. The aim of this study was to describe treatment practices, decision-making and symptoms during end-of-life care of IPF patients.

Methods

We identified 59 deceased patients from a national prospective IPF cohort study (FinnishIPF) and analyzed retrospectively their health care documentation during the 6 months that preceded death.

Results

Hospital was the place of death for 47 patients (80 %). A majority of the patients (93 %) were hospitalized for a mean of 30 days (range 1–96 days) during the last 6 months of their life. Altogether, patients spent 15 % of their last 6 months of life in a hospital. End-of-life decisions and do not resuscitate (DNR) orders were made for 19 (32 %) and 34 (57 %) of the patients, respectively, and 22 (42 %) of these decisions were made ≤ 3 days prior to death.

During the final hospital stay, antibiotics were given to 79 % and non-invasive ventilation to 36 % of patients. During the last 24 h of life, radiologic imaging or laboratory tests were taken in 19 % and 53 % of the hospitalized patients, respectively. These tests and life prolonging therapies were more common in tertiary hospitals compared to other places of death. Dyspnea (66 %) and pain (31 %) were the most common symptoms recorded. Opioids were prescribed to 71 % of the patients during the last week before death.

Conclusions

The majority of IPF patients died in a hospital with ongoing life-prolonging procedures until death. The frequent use of opioids is an indicator of an intention to relieve symptoms, but end-of-life decisions were still made very late. Early integrated palliative care with advance care plan could improve the end-of-life care of dying IPF patients.

Early seroconversion and rapidly increasing autoantibody concentrations predict prepubertal manifestation of type 1 diabetes in children at genetic risk

AIMS/HYPOTHESIS

The aim of the study was to investigate the timing of the appearance of autoantibodies associated with type 1 diabetes between birth and puberty, the natural fate of these autoantibodies and the predictive power of autoantibody concentrations for early progression to clinical diabetes.

METHODS

Children were recruited to the Type 1 Diabetes Prediction and Prevention Project, an ongoing study based on HLA-conferred genetic risk. Autoantibodies against islet cells, insulin, GAD65 and islet antigen 2 were analysed at 3-12 month intervals, starting from birth.

RESULTS

During the follow-up, 1,320 children (18.4% of the cohort of 7,165 children) were autoantibody positive in at least one sample. Altogether, 184 autoantibody-positive children progressed to type 1 diabetes. Seroconversion occurred at an early age in the progressors (median 1.5 years), among whom 118 (64%) and 150 (82%) seroconverted to autoantibody positivity before the age of 2 and 3 years, respectively. The incidence of seroconversion peaked at 1 year of age. Compared with other autoantibody-positive children, the median autoantibody levels were already markedly higher 3 to 6 months after the seroconversion in children who later progressed to diabetes.

CONCLUSIONS/INTERPRETATION

Early initiation of autoimmunity and rapid increases in autoantibody titres strongly predict progression to overt diabetes before puberty, emphasising the importance of early life events in the development of type 1 diabetes.

Synbiotic effects of lactitol and Lactobacillus acidophilus NCFM™ in a semi-continuous colon fermentation model

The effects of Lactobacillus acidophilus NCFM™, lactitol, and the combination of lactitol and L. acidophilus NCFM™ were studied with a semi-continuous colon fermentation simulation; consisting of compartments mimicking, ascending, transverse, descending and sigmoid colon and their conditions with faecal inoculation. L. acidophilus NCFM™ was detected throughout the colon simulator. Lactitol was utilised early on by the microbes in the proximal part of the simulator. Lactitol increased the total numbers of microbes and bifidobacteria, and decreased clostridia cluster IV, while L. acidophilus NCFM™ alone decreased the numbers of clostridia cluster XIV. Combination treatment increased the numbers of bifidobacteria. Furthermore, concentrations of acetic acid, butyric acid and the sum of total short-chain fatty acids were increased by both lactitol-including treatments. The treatment with L. acidophilus NCFM™ alone increased the concentration of propionic acid and butyric acid. L. acidophilus NCFM™ tended to increase the total concentrations of biogenic amines, while lactitol suppressed production of biogenic amines also in the presence of L. acidophilus NCFM™. True synergistic effects are suggested in stimulation of the production of butyrate, an important microbial metabolite for colon health. In conclusion, lactitol as well as the combination of lactitol and L. acidophilus NCFM™ were found to exhibit complementary beneficial effects on the colon microbial composition and activity.

Xylo-oligosaccharides and lactitol promote the growth of Bifidobacterium lactis and Lactobacillus species in pure cultures

The current screening study aimed at identifying promising prebiotic and synbiotic candidates. The fermentation of xylo-oligosaccharides, xylan, galacto-oligosaccharide, fructo-oligosaccharide, polydextrose, lactitol, gentiobiose and pullulan was investigated in vitro. The ability of these established and potential prebiotic candidates to function as a sole carbon source for probiotic (Bifidobacterium and Lactobacillus), intestinal and potential pathogenic microbes (Eubacterium, Bacteroides, Clostridium, Escherichia coli, Salmonella, and Staphylococcus) was assessed in pure cultures. Xylo-oligosaccharides were fermented with high specificity by the tested Bifidobacterium lactis strains and lactitol by lactobacilli, whereas galacto-oligosaccharides, fructo-oligosaccharides and gentiobiose were utilised by a larger group of microbes. Xylan, polydextrose and pullulan were utilised to a limited extent by only a few of the tested microbes. The results of this screening study indicate that xylo-oligosaccharides and lactitol support the growth of a limited number of beneficial microbes in pure cultures. Such a high degree of specificity has not been previously reported for established prebiotics. Based on these results, the most promising prebiotics and synbiotic combinations can be selected for further testing.

Xylo-oligosaccharides enhance the growth of bifidobacteria and Bifidobacterium lactis in a simulated colon model

A semi-continuous, anaerobic colon simulator, with four vessels mimicking the conditions of the human large intestine, was used to study the fermentation of xylo-oligosaccharides (XOS). Three XOS compounds and a xylan preparation were fermented for 48 hours by human colonic microbes. Fructo-oligosaccharides (FOS) were used as a prebiotic reference. As a result of the fermentation, the numbers of Bifidobacterium increased in all XOS and xylan simulations when compared to the growth observed in the baseline simulations, and increased levels of Bifidobacterium lactis were measured with the two XOS compounds that had larger distribution of the degree of polymerisation. Fermentation of XOS and xylan increased the microbial production of short chain fatty acids in the simulator vessels; especially the amounts of butyrate and acetate were increased. XOS was more efficient than FOS in increasing the numbers of B. lactis in the colonic model, whereas FOS increased the Bifidobacterium longum numbers more. The selective fermentation of XOS by B. lactis has been demonstrated in pure culture studies, and these results further indicate that the combination of B. lactis and XOS would form a successful, selective synbiotic combination.

Effect of infancy-onset dietary intervention on salivary cholesterol of children: a randomized controlled trial

This study investigated salivary cholesterol of children from 6 to 16 years of age in response to dietary intervention. One thousand sixty-two infants started in the prospective, randomized project. At 3 years of age, every fifth child was invited into the study (n=178). Of these, 148 enrolled, and 86 completed the oral sub-study at 16 years of age. The intervention aimed at restricting the child's saturated fat and cholesterol intake. Control children received no special recommendations. Every third year, paraffin-stimulated saliva samples (10.0 mL) were collected for cholesterol assays. Nutrient intakes and serum total cholesterol concentrations were regularly followed up by means of 4-day food records and blood samples. Intake of saturated fatty acids (SAFA) was lower in the intervention than in the control group (p<0.001). Salivary cholesterol concentration increased from 1.9 (±1.1) µmol/L at 6 years of age to 16.0 (±9.0) µmol/L at 16 years of age. The increase was smaller in the intervention than in the control group (p<0.001). The ratios of salivary to serum cholesterol concentrations tended to be higher in boys than in girls (p=0.07). Thus, dietary intervention was reflected in children's salivary cholesterol values more sensitively than in serum cholesterol values. (clinicaltrials.gov NCT00223600).

The effect of feeding essential oils on broiler performance and gut microbiota

1. In this study the effect of a blend of essential oils (EO) comprising 15 g/tonne thymol and 5 g/tonne cinnamaldehyde on the performance and intestinal microbiota of broilers was investigated. 2. A total of 720 male Ross broilers were divided into two dietary treatments with 12 replicate pens per treatment. Broilers were given a control soybean-wheat-based diet with or without added EO in two diet phases (0-21 d and 22-42 d). 3. The blend of EO increased body weight gain of broilers from 0 to 42 d by 45%. 4. Caecal microbiota were affected by the EO blend; in particular increases in the proportions of Lactobacillus and Escherichia coli at 41 d was observed. 5. The EO blend had major effects on caecal metabolites. The proportion of caecal butyrate at 20 and 41 d of age increased, whereas the proportion of caecal acetic acid at 20 d, and propionic acid and isovaleric acid at 41 d, decreased with the EO blend. In addition, the caecal proportion of spermine increased and tyramine decreased at 41 d of age with the EO treatment. 6. The present study shows that EO supplementation exerts a positive effect on intestinal microbiota with a concomitant enhancement in growth performance. The study suggests that modulation of broiler gut microbiota composition and activity through the administration of EO offers an effective means for improving broiler performance.

Dietary and lifestyle counselling reduces the clustering of overweight-related cardiometabolic risk factors in adolescents

AIM

The aim of this study was to evaluate the impact of individualised dietary and lifestyle counselling, primarily aimed to decrease serum low-density lipoprotein cholesterol, on the clustering of overweight-related cardiometabolic risk factors in children.

DESIGN AND PARTICIPANTS

The 7-month-old study children were randomized either to counselling (n = 540) or control group (n = 522).

MAIN OUTCOME MEASURES

The 5- to 15-year-old participants who fulfilled the international criteria were classified as overweight. Being in the highest [lowest for high-density lipoprotein (HDL) cholesterol] age- and gender-specific quintile of body mass index (BMI), blood pressure, serum triglycerides, HDL cholesterol or glucose was considered a risk factor. A cluster was defined as having high BMI and > or = 2 other risk factors.

RESULTS

The counselling did not reduce the prevalence of overweight in 5- to 15-year-old participants. From age 7 onwards, the proportion of children with > or = 2 risk factors was lower in the intervention than in the control group (p = 0.005). At the age of 15 years, 13.0% of girls and 10.8% of boys in the intervention group and 17.5% of girls and 18.8% of boys in the control group had the risk factor cluster (p = 0.046 for main effect of the study group). Having even one risk factor at the age of 5 years predicted the clustering of risk factors at the age of 15 years (OR: 3.8, p < 0.001).

CONCLUSION

Repeated, individualized dietary and lifestyle counselling may reduce the clustering of overweight-related cardiometabolic risk factors in adolescents even though the counselling is not intense enough to prevent overweight.

Burrowing behaviour affects Paraergasilus rylovi abundance in Anodonta piscinalis

Burrowing depth may affect predation rate, feeding ability and reproduction in bivalve clams. We studied the effect of burrowing depth on the abundance of the ergasilid Paraergasilus rylovi in the freshwater bivalve clam Anodonta piscinalis. We transplanted uninfected clams to a lake where they were allowed to choose their preferred burrowing depth, and were exposed naturally to copepodids of the parasite. There was a significant positive correlation between proportionate burrowing depth (PBD) and the abundance of P. rylovi at the end of the 17-day experiment, the deeper-burrowed clams harbouring more P. rylovi. Original PBD (0%, 50%, 100%) did not influence the final PBD or parasite abundance. Clam length affected PBD, smaller clams burrowing deeper, but it did not affect parasite abundance. Infected experimental clams and naturally-burrowed uninfected clams, both originating from the same lake, did not differ in their mean PBD. This indicated that burrowing of the experimental clams affected parasitism rather than the parasites altering burrowing of the clams. In line with the experimental result, we observed a significant positive correlation between PBD and the abundance of P. rylovi also among clams collected from 2 natural A. piscinalis populations.

Long-lasting effect of stress on susceptibility of a freshwater clam to copepod parasitism

The question whether a stress event can have a long-lasting effect on susceptibility to parasites was studied using a freshwater bivalve clam and its crustacean parasite as a model system. Anodonta piscinalis clams were collected from 2 populations during August-September 2002. Clams were transported to the laboratory and marked. The stressed clams were subjected to low oxygen for 25 days, while the unstressed control clams were caged in their lakes of origin for the same period. Then the clams were transported to a third lake where they were exposed to natural infections by the ergasilid copepod, Paraergasilus rylovi, 11 months after the stress event. The stressed clams were more intensively parasitized. They also showed lower growth, lower reproduction and lower survival than the unstressed control clams. The results indicate that susceptibility of A. piscinalis to P. rylovi infection may be condition dependent, and that stress may have a long-lasting, increasing effect on host susceptibility to parasitism in natural populations.

ASPECTS OF THE ECOLOGY AND NATURAL HISTORY OF PARAERGASILUS RYLOVI (COPEPODA, ERGASILIDAE) PARASITIC IN UNIONIDS OF FINLAND

The distribution of Paraergasilus rylovi in 17 populations of unionids was investigated. In 1 unionid population, the parasite was studied regarding host age, size, sex, and the reproductive period (occurrence of egg sacs). Results from pooled material from the years 1987--1989 and 1996 (southern Finland, 11 populations) indicated that Anodonta piscinalis (n = 1,359) is the main host (total mean prevalence 71% and intensity +/-SE of infection 16.4+/-0.6). Pseudanodonta complanata (n = 106) was infected occasionally (3% and 1.3+/-0.3), whereas Unio pictorum (n = 108) and U. tumidus (n = 17) were not infected. Results from 17 A. piscinalis populations showed that P. rylovi occurs in southern Finland but not in northern Finland. In A. piscinalis, the mean intensity of infection was higher in lake populations than in river populations. Both host age and length had a negative relationship with the intensity of P. rylovi infection. Host sex did not affect the intensity of infection. Egg sacs of P. rylovi were found from June to August. There was a tendency for higher intensities of infection in autumn. Infection by the digenean Rhipidocotyle fennica had no effect on the intensity of P. rylovi infection.

REDUCTION IN THE LEVEL OF INFECTION OF THE BIVALVE ANODONTA PISCINALIS BY THE COPEPOD PARAERGASILUS RYLOVI USING HIGH TEMPERATURE AND LOW OXYGEN

The aim of this study was to develop a method to kill or expel the gill-dwelling crustacean parasite Paraergasilus rylovi from a common freshwater clam, Anodonta piscinalis. Naturally infected clams were exposed to different water-quality treatments and monitoring in the laboratory. In a high-temperature treatment (26 C vs. control 18 C), the mean abundance of the parasite decreased to near zero in 7 days. Because only 2 clams of 72 died in this treatment during the 14-day experiment, the survival of the host was not seriously at risk at the high temperature. 'Low oxygen, no water change' (18 C) was the second most effective treatment, followed by a 'low-oxygen, water-flow' (18 C) treatment. At the end of the experiment, the mean parasite abundance was significantly lower in all the treatments than in the control clams (18 C). A few P. rylovi individuals abandoned the host at 26 C but died in a couple of days outside the host. However, the parasites lived on average (+/-SE) 12.7 +/- 0.9 days outside the clam, and were also shown to be capable of infecting another uninfected host individual, at 18 C. The results of the present study suggest that high temperature provides an effective, ecologically sustainable method to manipulate the intensity of P. rylovi infection.

Invasion of Salmonella into human intestinal epithelial cells is modulated by HLA-B27

OBJECTIVE

To investigate the influence of the major histocompatibility complex (MHC) class I molecule HLA-B27 on (i) the invasion of Salmonella and Yersinia into human intestinal epithelial cells, (ii) the survival of intracellular Salmonella in these cells, and (iii) the production of certain inflammatory cytokines by the cells after Salmonella infection.

METHODS

The human intestinal epithelial cell line Henle-407 was transfected with HLA-B27 DNA. These cells and HLA-B27-negative control cells were infected with Salmonella or Yersinia, and viable intracellular bacteria were determined as colony-forming units. Cytokine production was assayed with ELISA.

RESULTS

Salmonella invaded HLA-B27-positive Henle cells in higher numbers than HLA-B27-negative control cells. However, HLA-B27 did not affect the invasion of Yersinia or the survival of the intracellular bacteria in these intestinal epithelial cells. Salmonella infection induced production of interleukin-8 (IL-8), IL-6 and monocyte chemotactic protein 1 (MCP-1) by Henle cells that was not affected by HLA-B27 in a specific way.

CONCLUSIONS

These findings suggest that HLA-B27 enhances the invasion of Salmonella into intestinal epithelial cells. The interaction between bacteria and intestinal epithelial cells plays an important role during the early phases of ReA. HLA-B27-linked modulation of Salmonella invasion may lead to an increased load of Salmonella in intestinal tissue and thus increased susceptibility to reactive arthritis.

Intestinal uptake of betaine in vitro and the distribution of methyl groups from betaine, choline, and methionine in the body of broiler chicks

The efficiency of betaine absorption into small intestinal slices of broiler chicks was studied in vitro with 14C-labeled betaine. The relative proportion of Na+-coupled betaine uptake, as well as the total uptake capacity was larger in the duodenum than in the jejunum. Dietary betaine increased the Na+-coupled uptake in the duodenum. In in vivo-experiments, methyl-14C-labeled betaine, methionine, or choline was fed to broiler chicks. Betaine appeared in the blood more rapidly, and reached a higher total concentration than choline or methionine. The data suggest that choline and methionine were associated with plasma lipoproteins whereas betaine remained free in the plasma. The label distribution in liver, kidney, and intestinal tissues was studied 24 h after label ingestion. Most of the label from betaine was found in the aquaeous phase in the muscle, while in the liver and jejunum the label from betaine was distributed more evenly between the aquaeous, lipid, and protein phases. Label from choline accumulated in the lipid fraction, particularly so in the liver, whereas label from methionine showed a more variable distribution pattern. The distribution results are interpreted in terms of specific roles of betaine, choline, and methionine in methyl group metabolism.

Memory and metamemory functioning among depressed patients

Memory and metamemory functioning were studied among 30 adult patients suffering from major depression. The results indicate that, besides showing signs of cognitive slowing, the patients were especially vulnerable to visual memory impairment, whereas verbal, short-term memory, and recall by recognition were more often unaffected. The patients whose depression was characterized by physiological symptoms, such as loss of appetite and sleep disturbances, showed impairment in traditional short-term memory measures, whereas there was no firm connection between cognitive or behavioral depressive symptoms and memory functioning. The depressive patients' generalized view of their memory capability was strongly underestimated, whereas online metamemory accuracy by which one perceives and makes inferences about one's performance was adequate.

Human monocytic U937 cells kill Salmonella in vitro by NO-independent mechanisms

Nitric oxide (NO) has a central role in host defense against intracellular microbes. HLA-B27 has been shown to directly modulate host-microbe interaction in vitro, leading to the impaired elimination of Salmonella in human monocytic U937 cells. Here, we studied whether impaired elimination of Salmonella would result from differences in NO production between HLA-B27- and HLA-A2-transfected U937 cells. Both human monocytic transfectants produced NO equally well and killed Salmonella via NO-independent mechanisms.

Increased parasite abundance associated with reproductive maturity of the clam Anodonta piscinalis

Several studies on vertebrates have demonstrated that reproductive activities may increase the parasite load, but this has not been shown in invertebrate hosts. We studied abundance of a potentially harmful gill parasite, the ergasilid copepod Paraergasilus rylovi, from the freshwater bivalve host Anodonta piscinalis in relation to reproductive maturity of the host in the field. Prevalence of this previously unstudied parasite varied from 90 to 100%, and the mean parasite abundance from 16.3 to 28.8 among 3 study populations. Abundance of P. rylovi increased with host size. In the maturating age groups (3-5 yr) the length-adjusted mean parasite abundance among mature, reproducing female clams that brooded glochidia larvae was 2 times higher than in nonreproducing females, the observed pattern being consistent among the 3 study lakes. Alternative, mutually nonexclusive explanations may be found for the result. For example, changes in clam behavior or filtration activity accompanying maturation can increase host exposure to parasites, or reproduction may decrease energy available to host immunologic defense. However, the present result indicates that maturation, and reproduction, is associated with increased parasite abundance in A. piscinalis, an invertebrate host.

Structural basis for light activation of a chloroplast enzyme: the structure of sorghum NADP-malate dehydrogenase in its oxidized form

Some key chloroplast enzymes are activated by light via a ferredoxin-thioredoxin reduction system which reduces disulfide bridges in the enzymes. We describe for the first time the structural basis for the redox activation of a chloroplast enzyme, the NADP-dependent malate dehydrogenase (MDH) from Sorghum vulgare whose structure has been determined and refined at 2.4 A resolution. In addition to the normal structural components of MDHs, the enzyme exhibits extensions at both the N- and C-termini, each of which contains a regulatory disulfide bridge which must be reduced for activation. The N-terminal disulfide motif is inserted in a cleft between the two subunits of the dimer, thereby locking the domains in each subunit. The C-terminal disulfide keeps the C-terminal residues tight to the enzyme surface and blocks access to the active site. Reduction of the N-terminal disulfide would release the stopper between the domains and give the enzyme the necessary flexibility. Simultaneous reduction of the C-terminal disulfide would free the C-terminal residues from binding to the enzyme and make the active site accessible.

The three-dimensional structures of two toxins from snake venom throw light on the anticoagulant and neurotoxic sites of phospholipase A2

The three-dimensional structures of the class II anticoagulant phospholipase A2 (PLA2) toxin RVV-VD from the venom of Russell's viper, Vipera russelli russelli, and the class I neurotoxic PLA2 Notechis II-5 from the, Australian tiger snake, Notechis scutatus scutatus, were determined to 2.2 A and 3.0 A resolution, respectively. Both enzymes are monomeric and consist of 121 and 119 residues, respectively. A comparison of ten class I/II PLA2 structures showed, among other differences, that the beta-sheet of these enzymes (residues 76-83) is about 90 degrees less twisted in class I than in class II PLA2s. This, along with the insertion of some residues in the region 57-59 in class I enzymes (the elapid loop), could be the main reason for the significant difference in the anticoagulant and (presynaptic) neurotoxic properties between the two classes of PLA2. It seems apparent from sequence and structural comparisons that the toxic site of PLA2 responsible for the strong anticoagulancy of these toxins consists of a negatively charged part, Glu53, together with a positively charged ridge of lysine residues free for intermolecular interactions. These lysines differ between the two classes of PLA2.

Rate effect and mismatch responses in the somatosensory system: ERP-recordings in humans

In the first experiment, somatosensory event-related potentials (SERPs) were recorded to tactile pulses and vibration bursts applied to the left middle finger in trains of 4-8 stimuli with 1 s intervals. In addition to the negative N140 deflection, also the positive P50, P100 and P300 waves attenuated in amplitude with stimulus repetition. These decreases were immediate, there being no marked further amplitude attenuation after the second stimulus. The locus of this rate effect appears not to be the primary SI or SII, but rather prefrontal cortices or some deeper structures. In the second experiment, vibratory stimuli of different frequencies or at different skin sites were presented using the oddball paradigm. When the deviant stimulus was a high-frequency vibration burst, it elicited a distinct N250 deflection, probably analogous to the auditory N2b. When the deviation was a change in the stimulation site, no N250 deflection but instead an extra negativity between 100-200 ms latency, probably analogous to the auditory mismatch negativity, was observed.

Crystallographic investigation of the dependence of calcium and phosphate ions for notexin

The crystal structure of the neurotoxic phospholipase A2, notexin, revealed three binding sites for sulphate ions which were suggested to be phosphate binding sites of importance for the activity of the toxin. The present investigation shows that the sulphate ion bound to the major binding site alters the structure of residues 60-75. In the absence of sulphate and phosphate, the structure of this loop has a conformation which partly resembles the non-neurotoxic PLA2s. The affinity of notexin for phosphate is 17 microM, as measured by the increase in fluorescence at 345 nm. Since the concentrations of phosphate and sulphate ions in blood plasma are 3 and 1 mM, respectively, the binding site must be occupied under physiological conditions. This major sulphate/phosphate binding site explains the specific affinity labelling by pyridoxal phosphate. Pyridoxal phosphate binds to this anion binding site which allows the reaction with Lys-88 or Lys-89. The structure of notexin in the presence and absence of Ca2+ shows only small local structural differences.

Crystal structure of Arabidopsis thaliana NADPH dependent thioredoxin reductase at 2.5 A resolution

Thioredoxin exists in all organisms and is responsible for the hydrogen transfer to important enzymes for ribonucleotide reduction and the reduction of methionine sulphoxide and sulphate. Thioredoxins have also been shown to regulate enzyme activity in plants and are also involved in the regulation of transcription factors and several other regulatory activities. Thioredoxin is reduced by the flavoenzyme thioredoxin reductase using NADPH. We have now determined the first structure of a eukaryotic thioredoxin reductase, from the plant Arabidopsis thaliana, at 2.5 A resolution. The dimeric A. thaliana thioredoxin reductase is structurally similar to that of the Escherichia coli enzyme, and most differences occur in the loops. Because the plant and E. coli enzymes have the same architecture, with the same dimeric structure and the same position of the redox active disulphide bond, a similar mechanism that involves very large domain rotations is likely for the two enzymes. The subunit is divided into two domains, one that binds FAD and one that binds NADPH. The relative positions of the domains in A. thaliana thioredoxin reductase differ from those of the E. coli reductase. When the FAD domains are superimposed, the NADPH domain of A. thaliana thioredoxin reductase must be rotated by 8 degrees to superimpose on the corresponding domain of the E. coli enzyme. The domain rotation we now observe is much smaller than necessary for the thioredoxin reduction cycle.

Survival and degradation of Salmonella enterica serotype Enteritidis in intestinal epithelial cells in vitro

The survival and fate of Salmonella enterica serotype Enteritidis in Henle-407 human intestinal epithelial cells was investigated during prolonged incubation to evaluate the persistence of causative microbes and the relationship to patients developing reactive arthritis. Most of the bacteria were killed and degraded quite soon after infection of the cells, but there were still live bacteria inside the cells for up to 14 days. These results suggest that in patients developing reactive arthritis the salmonellae could persist in the epithelial cells and spread within the host to the joint and be present there at the time of the inflammatory response. Production of marked amounts of nitric oxide was observed as a novel response to salmonella infection in human intestinal epithelial cells. The present experimental procedure appears to be a suitable model to further investigate host-bacteria interaction in HLA-B27 positive cells from patients developing reactive arthritis.

Spectrum of 2,836 cases of invasive bacterial or fungal infections in children: results of prospective nationwide five-year surveillance in Finland. Finnish Pediatric Invasive Infection Study Group

In a prospective nationwide laboratory-based surveillance study of all invasive bacterial and fungal infections among children < 16 years of age, 2,836 clinical cases were registered during the 5-year period 1985-1989. Of these cases, 136 were polymicrobial. During the study period, nationwide administration of Haemophilus influenzae type b conjugate vaccine reduced the incidence rates of invasive infection caused by this organism. The most common clinical diagnosis (48% of cases) was bacteremia without an identified focus of infection. The age-specific annual incidence rates of all invasive infections in children < or = 15 years of age, in children < or = 4 years of age, in children < or = 1 year of age, and in children < or = 28 days of age were 55.8, 141.4, 272.7, and 2,749.0 cases/100,000 person-years, respectively. Thirty percent of the children in the study had an underlying condition predisposing to infection. The case-fatality rate was 4.1% for all cases of invasive infection.

Crystal structure of thioredoxin-2 from Anabaena

BACKGROUND

Thioredoxins are ubiquitous proteins that serve as reducing agents and general protein disulfide reductases. The structures of thioredoxins from a number of species, including man and Escherichia coli, are known. Cyanobacteria, such as Anabaena, contain two thioredoxins that exhibit very different activities with target enzymes and share little sequence similarity. Thioredoxin-2 (Trx-2) from Anabaena resembles chloroplast type-f thioredoxin in its activities and the two proteins may be evolutionarily related. We have undertaken structural studies of Trx-2 in order to gain insights into the structure/function relationships of thioredoxins.

RESULTS

Anabaena Trx-2, like E. coli thioredoxin, consists of a five-stranded beta sheet core surrounded by four alpha helices. The active site includes a conserved disulfide ring (in the sequence 31WCGPC35). An aspartate (E. coli) to tyrosine (Trx-2) substitution alters the position of this disulfide ring relative to the central pleated sheet. However, loss of this conserved aspartate does not affect the disulfide geometry. In the Trx-2 crystals, the N-terminal residues make extensive contacts with a symmetry-related molecule with hydrogen bonds to residues 74-76 mimicking thioredoxin-protein interactions.

CONCLUSIONS

The overall three-dimensional structure of Trx-2 is similar to E. coli thioredoxin and other related disulfide oxido-reductases. Single amino acid substitutions around the protein interaction area probably account for the unusual enzymatic activities of Trx-2 and its ability to discriminate between substrate and non-substrate peptides.

YadA mediates specific binding of enteropathogenic Yersinia enterocolitica to human intestinal submucosa

The binding of live Yersinia enterocolitica to frozen sections of human intestine was investigated qualitatively by monitoring the binding of bacteria by using Gram or immunoperoxidase staining as well as quantitatively by a new enzyme immunoassay-on-slide method. We have demonstrated that the binding of various Y. enterocolitica serotypes and Escherichia coli clones to frozen sections of human intestine is mediated by the Yersinia adhesin, YadA. The YadA-mediated binding occurs mainly at the submucosal layer of the intestinal wall and only to a limited extent at the mucosal layer; there binding is mostly to the mucin threads. In addition, partially purified YadA binds to frozen sections with a pattern similar to that of intact bacteria. Collagen, laminin, or partially purified YadA only partially inhibited the YadA-mediated binding of bacteria, presumably because YadA is multifunctional. A combination of collagen and laminin inhibited the binding more efficiently. Therefore, YadA may be involved in the interactions with the extracellular matrix molecules after the invasion of the intestinal tissue.

Identification and characterization of the second regulatory disulfide bridge of recombinant sorghum leaf NADP-malate dehydrogenase

Unique among malate dehydrogenases, the NADP-dependent chloroplastic form undergoes a reductive activation in the light. This process is thioredoxin-mediated and involves at least two disulfides. Only one of them, situated near the N terminus, has been localized. The enzyme also bears 2 cysteines at the C terminus. The possible role of these cysteines was investigated by replacing them separately, or together, by alanines, by site-directed mutagenesis. The proteins altered at the C terminus were still dithiol-dependent for full activation, with activation kinetics similar to those of the wild type enzyme. However, they exhibited a weak activity in the oxidized form with a dramatically increased Km for oxalacetate. Their activation was not inhibited by NADP. When C-terminal Cys mutations were combined with N-terminal Cys mutations, permanently active, thioredoxin-independent enzymes were obtained. They exhibited the biochemical properties of the activated wild type protein. Clearly, the 2 C-terminal cysteines constitute the second thioredoxin-dependent regulatory disulfide of NADP-malate dehydrogenase. Integrating our data about the characteristics of each of the regulatory disulfides and information from three-dimensional structure modeling, we propose a model for the redox control of NADP-malate dehydrogenase.

An elongated form of T4 glutaredoxin with four extra residues

Two different forms of T4 glutaredoxin (thioredoxin) arising from the same gene on a multicopy plasmid in an Escherichia coli expression system have been isolated and characterized. Up to one-fourth of purified T4 glutaredoxin has an extension of four amino acids in the carboxy terminus, with the sequence aspartate, arginine, isoleucine, lysine. This four-residue extension may be caused by a translational +1 frameshift at the UGA terminator codon.

Screening of beta-blockers in human serum by ion-pair chromatography and their identification as methyl or acetyl derivatives by gas chromatography-mass spectrometry

A simultaneous screening method for atenolol, acebutolol, metoprolol, oxprenolol, alprenolol and propranolol by ion-pair chromatography with a column-switching technique was developed. The serum samples were purified using either liquid-liquid extraction or solid-phase extraction methods. The pretreatment of the samples consisted of hydrolysis and protein precipitation. The drug separation was on either octadecylsilica or polymer-based alkyl column material. Binary eluent mixtures containing methanol and a buffer solution with a quaternary ammonium salt as an ion-pair former were used. Detection of the compounds in liquid chromatographic analysis was based on ultraviolet spectra. The effects of methanol, two buffers and the ion-pair former on the retention of the compounds were studied. The determination limits ranged from nanograms to micrograms in the ion-pair chromatographic method, depending on the drug studied. Identification was based on the mass spectra or, if necessary, on selected-ion monitoring spectra of either the methylated or the acetylated compounds obtained by means of gas chromatography-electron impact or negative chemical ionization mass spectrometry. The detection limits for the identified compounds were in the picogram range. The matrix effect was strong, and this resulted in determination limits in the nanogram range with the scan method.

A putative glutathione-binding site in T4 glutaredoxin investigated by site-directed mutagenesis

A glutathione monomer has been docked into the active site cleft of T4 glutaredoxin (previously called T4 thioredoxin) using molecular graphics. The central part of the cleft is formed by the side chain of Tyr-16 on one side and the residues Thr-64, Met-65, and Pro-66 on the other. The entire glutathione molecule fits well into the cleft. A cis-peptide bond between the residues Met-65 and Pro-66 allows glutathione to bind in an anti-parallel fashion to residues 64-66. Hydrogen bonds can be formed between Met-65 and the glutathione cysteine. This binding positions the glutathione sulfur atom ideally for reaction with the glutaredoxin disulfide. In the model, glutathione can form a hydrogen bond to the hydroxyl group of Tyr-16. Charged interactions at opposite ends of the binding cleft are provided by His-12 and Asp-80. The negatively charged alpha-carboxyl group of glutathione may interact with a positive helix dipole of the protein. Fifteen mutant T4 glutaredoxins have been produced and assayed for glutathione binding by determining thioltransferase activity. Mutant proteins with substitutions in the sides of the cleft (Tyr-16, Pro-66) exhibited the most marked decreases in thioltransferase activity. Mutation of His-12 to a serine decreases the catalytic efficiency whereas substitution of Asp-80 by serine increases the catalytic efficiency. A double mutant, D80S;H12S, has much less affinity for glutathione than either single mutant. Substitution of Cys-14 produces an inactive protein, whereas C17S retains some thioltransferase activity.

Malaria prophylaxis with proguanil to Namibian refugee children in Angola

Following a presumptive treatment with 35 mg chloroquine base/kg, 484 Namibian children between 5 months and 5 years of age received 50 mg of proguanil daily for 4 months. They were compared with 268 children living in a very adjacent area who received vitamin tablets after the initial chloroquine medication. Fewer fever episodes were recorded among the children who received proguanil and they were also requiring less presumptive treatments with chloroquine during the period of study, but there were only minor differences in parasite rate between the two groups at the end of the study period. Despite the reduction of morbidity, the required efforts were too large to justify another period of drug prophylaxis.

C-reactive protein compared with white blood cell count and erythrocyte sedimentation rate in the diagnosis of acute appendicitis in children

Acute abdominal symptoms in 162 children were investigated with rapidly quantified C-reactive protein (CRP), white blood cell (WBC) count and erythrocyte sedimentation rate (ESR) as laboratory parameters. When the symptoms had been present for at least 12 hours, the CRP level was greater than 10 mg/l in 72% of cases with histologic evidence of appendicitis, while leukocytosis (WBC greater than 15 000/mm3) and raised ESR (greater than 20 mm/l h) were found in 58% and 51%, respectively. If appendicitis had progressed to gangrenous stage, however, CRP alone was capable of identifying 83% of cases, while 76% had leukocytosis and 60% elevated ESR. When perforation had occurred there was greatly increased CRP and invariably leukocytosis, but elevated ESR in only 60%. With the combination CRP and WBC count (using rise in one or both), 88% of all appendicitis cases could be identified, and at least 96% of those with gangrene or perforation. The predictive value of combined positive CRP and WBC tests was not less than 93%.

Acute appendicitis not associated with social class among children

Acute appendicitis has previously been found to be associated with social class. In an attempt to confirm this, 125 patients with histologically verified acute appendicitis were compared with 1802 control children, randomly selected from the schools of the City of Helsinki. Social class determination was based on father's occupation in families with two parents, and on mother's occupation in single provider families. No association with social class was found. The proportion of single provider families was around 25% among both cases and controls. Appendicitis patients are one potential source of control groups in epidemiological studies.

The normal human magnetocardiogram. II. A multipole analysis

This paper presents a multipole analysis of the QRS complex of the normal magnetocardiogram (MCG) of six normal subjects. The multipole strengths up to the octupole term were determined from the measured distribution of the z-component of the cardiac magnetic field (the component perpendicular to the frontal plane). This equivalent magnetic multipole generator was found to represent the cardiac magnetic field with a minimum error of less than 10%. The dipolar term of the expansion was found to represent the field distribution with reasonable accuracy early during ventricular activation, whereas late during activation, the higher multipole terms were clearly more significant.