bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of acute hypovolaemia by furosemide on tracheal transepithelial potential difference and mucus in dogs
Authors: Nakagawa N.K. , Donato-Júnior F. , Kondo C.S. , King M. , Auler-Júnior J.O.C. , Saldiva P.H.N. , Lorenzi-Filho G.
Published: October 2004

Furosemide is a potent diuretic that affects water transfer across the respiratory epithelium, which is closely related to the transepithelial potential difference (PD). Water is a critical factor that determines mucus transport; an important lung defence mechanism that removes particles and microorganisms from the respiratory system.

The aim of the present study was to investigate the acute effects of furosemide and hypovolaemia on tracheal PD and mucus properties. A total of 36 male mixed-breed dogs were submitted to anaesthesia, mechanical ventilation and haemodynamic monitoring. They were randomly assigned to three groups consisting of: a control group, a furosemide (40 mgi.v.) + hypovolaemia group, and a furosemide (40 mgi.v.) + volume replacement group. Tracheal PD and mucus samples were collected at time 0, 1 and 2 h after intervention. Mucus properties were analysed by means of a magnetic microrheometer andin vitromucociliary transportability on the frog palate.

Compared to controls, furosemide decreased PD to intermediate values, and only significantly when associated with hypovolaemia (−13±5 and −8±2 mV, time 0 and 2 h, respectively).

In addition to the direct effect of furosemide, these results indicate that hypovolaemia also affects ion transport in the tracheal membrane. Furosemide and hypovolemia have no acute effects on respiratory mucus properties.
The NICE schizophrenia guidelines: the challenge of implementation1
Authors: Rowlands Paul
Published: October 2004

I explore implementation of the National Institute for Clinical Excellence's clinical guidelines for schizophrenia at an individual practitioner level and at an organisational level. Integrating effective individual and team approaches into a systematic organisational approach with collaborative working between managers, clinicians and service users will be essential to successful implementation and is likely to require a strong lead from senior clinicians. Implementation is likely to be best achieved through a sense of ownership of the guidelines and a process that borrows from their spirit, which emphasises collaboration, building on the strengths and good practice already present. Although full implementation will require additional resources, current resources must be employed effectively. The task of implementation is immense, however, and in some areas resource deficiencies and other structural problems might present insurmountable obstacles.
Services for personality disorder: organisation for inclusion
Authors: Bateman Anthony W. , Tyrer Peter
Published: October 2004

Mental health services are not yet organised to allow patients with personality disorders easy access, and practitioners lack the necessary skills to implement effective treatment. A number of service models have developed, albeit without a clear evidence-base. These include sole-practitioner, divided-functions and specialist-team models. In general, a divided-functions or specialist-team model is probably best for reducing risk and improving outcomes. Both models present difficulties with integrating treatment, but these can be overcome by good communication. Good management of patients requires careful assessment of need and risk, a consistent approach, constancy of staff, team coherence and adequate in-patient support. Not all practitioners can treat patients with personality disorders and the interpersonal skills of the mental health professional may be crucial in maintaining a patient in treatment.
Suicide following discharge from in-patient psychiatric care
Authors: Crawford Mike J.
Published: October 2004

The risk of suicide is higher during the period immediately following discharge from in-patient psychiatric care than at any other time in a service user's life. Demographic and clinical risk factors for suicide in this period are similar to those for suicide at other times and may not be specific enough to enable identification of those at greatest risk. Epidemiological studies suggest that factors related to service organisation and delivery (e.g. social support and continuity of care) are also important in the aetiology of suicide following hospital discharge. Interventions aimed at helping people in the period immediately following discharge from in-patient care have been developed. Although the effect of these interventions on suicidal behaviour has not been examined, available evidence suggests that efforts to increase patients' confidence and level of social support may be of value.
Association between prenatal exposure to analgesics and risk of schizophrenia
Authors: Sørensen Holger J. , Mortensen Erik L. , Reinisch June M. , Mednick Sarnoff A.
Published: October 2004

Background

Disturbances in the central nervous system originating during foetal life may increase the risk of schizophrenia.

Aims

To illuminate the hypothesis that prenatal exposure to analgesics may affect foetal neurodevelopment, leading to increased risk of schizophrenia in adulthood.

Method

Using data from the Copenhagen Perinatal Cohort and from the Danish Psychiatric Central Register, we studied the relationship between prenatal exposure to analgesics and the risk of schizophrenia. The effect of prenatal exposure was adjusted for parental history of schizophrenia, second-trimester viral infections, concomitant drug treatment during pregnancy, an index of pregnancy complications, parental social status and parental age.

Results

In a risk set of 7999 individuals, 116 cases of schizophrenia were found (1.5%). Prenatal exposure to analgesics in the second trimester was associated with an elevated risk (adjusted odds ratio 4.75, 95% CI1.9–12.0). Independent of the covariates, the effect remained statistically significant.

Conclusions

Independent of a wide range of possible confounders, a significant association between second-trimester exposure to analgesics and increased risk of schizophrenia was observed.
Factors influencing the development and amelioration of suicidal thoughts in the general population
Authors: Gunnell D. , Harbord R. , Singleton N. , Jenkins R. , Lewis G.
Published: October 2004

Background

The incidence of suicidal thoughts in the British population is unknown.

Aims

To determine the factors associated with the development of, and recovery from, suicidal thoughts.

Method

An 18-month follow-up survey investigated 2404 of the adults who took part in the second National Psychiatric Morbidity Survey.

Results

The annual incidence of suicidal thoughts was 2.3%. Incidence was highest in women and among 16- to 24-year-olds. Increased incidence was associated with not being in a stable relationship, low levels of social support and being unemployed. Fifty-seven percent of those with suicidal thoughts at baseline had recovered by the 18-month follow-up interview.

Conclusions

Risk factors for suicidal thoughts are similar to those for completed suicide, although the age and gender patterning is different. Fewer than 1 in 200 people who experience suicidal thoughts go on to complete suicide. Further study into explanations for the differences in the epidemiology of suicidal thoughts and suicide is crucial to understanding the pathways (protective and precipitating) linking suicidal thoughts to completed suicide and should help inform effective prevention of suicide.
Homicide and mental illness in New Zealand, 1970–2000
Authors: Simpson Alexander I. F. , Mckenna Brian , Moskowitz Andrew , Skipworth Jeremy , Barry-Walsh Justin
Published: October 2004

Background

Homicides by mentally ill persons have led to political concerns about deinstitutionalisation.

Aims

To provide accurate information about the contribution of mental illness to homicide rates.

Method

Retrospective study of homicide in New Zealand from 1970 to 2000, using data from government sources. ‘Mentally abnormal homicide’ perpetrators were defined as those found unfit to stand trial, not guilty by reason of insanity, convicted and sentenced to psychiatric committal, or convicted of infanticide. Group and time trends were analysed.

Results

Mentally abnormal homicides constituted 8.7% of the 1498 homicides. The annual rate of such homicides was 1.3 per million population, static over the period. Total homicides increased by over 6% per year from 1970 to 1990, then declined from 1990 to 2000. The percentage of all homicides committed by the mentally abnormal group fell from 19.5%in 1970 to 5.0% in 2000. Ten percent of perpetrators had been admitted to hospital during the month before the offence; 28.6% had had no prior contact with mental health services. Victims were most commonly known to the perpetrator (74%).

Conclusions

Deinstitutionalisation appears not to be associated with an increased risk of homicide by people who are mentally ill.
What attitudes do psychiatrists hold towards people with mental illness?
Authors: Kingdon David , Sharma Tonmoy , Hart Deborah ,   Deborah Hart The Schizophrenia Subgroup of The Royal College of Psychiatrists' Changing Minds Campaign
Published: October 2004

Aims and Method

To investigate the attitudes that psychiatrists hold towards people with mental illness. Each member of the Royal College of Psychiatrists in the UK was sent a questionnaire based on previous research in this area, supplemented with relevant questions on management.

Results

2813 of 6524 questionnaires were returned (43%). Psychiatrists' attitudes compared favourably with those of the general population. Among other findings, they believed that the risk of dangerousness was overemphasised, that misdiagnosis of schizophrenia in Black people is common, and that polypharmacy and the use of antipsychotic medication above British National Formulary levels occurs too often.

Clinical Implications

Psychiatrists' attitudes are substantially more favourable towards people with mental illness than those of the general population with individual, but important, exceptions. Some aspects of psychiatric management, especially of antipsychotic medication, may undermine this, however. Comparison with other groups, e.g. general practitioners, nurses and social workers, would be useful in planning how to reduce the stigmatisation of people with mental illness.
Demystifying the business plan
Authors: George Sanju , Dawson Angus
Published: October 2004

Changes in the structure and organisation of health services are requiring clinicians to take on managerial and administrative responsibilities The need for training in managerial skills has, therefore, been endorsed by the College. This article discusses one of the key concepts in management, the business plan. We briefly describe the steps involved in writing a business plan, illustrated by a hypothetical example.
Diverse clinical and pathologic features of gastric carcinoid and the relevance of hypergastrinemia
Authors: Gough David B. , Thompson Geoffrey B. , Crotty Thomas B. , Donohue John H. , Kvols Larry K. , Carney J. Aidan , Grant Clive S. , Nagorney David M.
Published: October 2004

The etiology, prognosis, and optimal management of primary gastric carcinoids remain controversial. Records of 36 consecutive patients with gastric carcinoid (15 men) were reviewed retrospectively between 1975 and 1990. Follow‐up was complete in 97% of cases. Mean age at diagnosis was 58.4 years (range 24–82 years). The clinical presentations included anemia (72%), pain (69%), and carcinoid syndrome (11%). Associated autoimmune and endocrine abnormalities were common and included atrophic gastritis (67%), pernicious anemia (58%), hypothyroidism (39%), diabetes (19%), Addison's disease (6%), and hyperparathyroidism (6%). Lesions were nonantral in 78%, involving only the corpus in 42%, the fundus in 28%, and only the antrum in 8%; 42% were multiple. Urinary 5‐hydroxyindoleacetic acid (5‐HIAA) and serum gastrin levels were elevated in 17% and 50% of those tested, respectively. Histologic examination revealed that 28% of lesions were ≥2 cm, and 33% had liver metastases on presentation or developed them during follow‐up. Eight patients (22%) died of tumor with a median survival of 39 months. The presence of metastases, atypical histology, serosal involvement, and size > 2 cm were adverse prognostic factors. In patients without hypergastrinemia (n=6), 66% developed metastases, 60% had elevated 5‐HIAA, and 50% died of carcinoid tumor. In sharp contrast, those patients with hypergastrinemia and “typical” gastric carcinoids (n=15), metastases and death did not occur (p<0.003 and p < 0.005, respectively, compared with eugastrinemic patients). In the latter group (hypergastrinemia and typical histology), pernicious anemia was common (73%); solitary lesions and serosal penetration were seen comparatively less often (33% versus 100%, p<0.005 and 0% versus 33%, p<0.05, respectively); and no lesion measured > 2.0 cm compared to 66% in the group without elevated gastrin (p<0.002). No patient with hypergastrinaemia had elevated levels of 5‐HIAA. Overall survival at 5 and 10 years was 58% and 28%, respectively. Survival was 80% at 5 and 10 years in the hypergastrinemic group. Gastric carcinoid tumors that are histologically atypical, large (>2 cm), or present without elevated gastrin are potentially lethal and require aggressive therapy. In contrast, gastric carcinoids with typical histology and hypergastrinemia are rarely lethal, and conservative management with local excision and close observation is appropriate.
Radioiodine‐associated thyroid cancers
Authors: Tezelman Serdar , Grossman Richard F. , Siperstein Allan E. , Clark Orlo H.
Published: October 2004

Numerous investigations document that exposure to low dose external therapeutic radiation leads to the development of benign and malignant thyroid neoplasms. There is consideble controversy, however, concerning whether radioactive iodine (131I) causes thyroid cancer. The aim of this investigation was to examine our experience and that in the literature related to this problem. From 1982 to March 1993 seven of 373 patients (1.9%) with thyroid cancer who were treated by one surgeon had a history of treatment with radioactive iodine for Graves' disease and toxic nodular goiter. Sixty‐five patients have previously been reported in the literature from 1957 to present. Our patients (five women, two men) ranged in age from 26 to 80 years (mean 57 years). The interval between the exposure to the internal radiation and development of cancer ranged from 3 to 29 years (mean 11.4 years), and the mean age at the time of 131I treatment was 45 years (18–76 years). The therapeutic dose of 131I was 5 to 100 mCi (mean 25.3 mCi) in our patients. Two of our patients received 131I twice. The age of patients reported in the literature at the time of 131I treatment ranged from 7 to 74 years (mean 48 years). The mean therapeutic dose of 131I was 20.6 mCi (1.25–180.0 mCi) and the latent period was documented for a mean 8.7 years (0.25–28.0 years) in these patients. Three of 29 patients in the literature received 131I twice. Fine‐needle aspiration cytology of thyroid nodules was positive for cancer in six of our patients (86%). All patients were treated by total thyroidectomy, and three of them had a modified neck dissection. Six of our seven patients had invasive papillary thyroid carcinoma (stage III disease), and the seventh patient had extensive nodal metastasis and intrathyroidal invasion. Invasion into adjacent muscle and soft tissue were found in four patients, and two had tracheal invasion. Two patients had lymph node metastases. There were no postoperative complications. One patient (14%), however developed recurrent papillary and anaplastic thyroid cancer in his left neck and mediastinum 2 years after total thyroidectomy. He had extensive pulmonary metastases and malignant pleural effusions and died 23 days after a left modified radical neck dissection. In conclusion, radioactive iodine in doses to treat Graves' disease may increase the risk of developing thyroid cancer. These cancers are discovered at a later stage and appear to be aggressive.
Thyroperoxidase immunodetection for the diagnosis of malignancy on fine‐needle aspiration of thyroid nodules
Authors: Henry Jean‐Francois , Denizot Anne , Porcelli Alberto , Villafane Marcelo , Zoro Patricia , Garcia Stéphane , De Micco Cathérine
Published: October 2004

We have previously demonstrated that in 95.6% of malignant thyroid tumors the enzyme thyroid peroxidase (TPO) presents antigenic changes detectable by a monoclonal antibody termed MoAb47. The aim of this study was to investigate the interest of TPO immunodetection for the diagnosis of malignancy on fine‐needle aspiration biopsy (FNAB) of thyroid nodules. The study was performed on 300 patients. Slides of FNAB aspirate were air‐dried and stained by anti‐TPO‐MoAb47. According to the percentage of TPO‐positive epithelial cells, patients were divided into two groups: benign (<80%) and malignant (<80%). In 279 cases additional slides were available for Giemsa stain and standard cytology. All the patients were operated on, and the final diagnosis was recorded as benign in 248 cases (183 macrofollicular nodules, 23 microfollicular adenomas, 18 atypical adenomas, 11 oncocytomas, 11 thyroiditis, 2 Graves' disease) and malignant in 52 cases (44 papillary carcinomas and 8 follicular carcinomas). Samples from 215 of 248 benign nodules yielded 80% to 100% TPO‐positive cells, whereas samples from all malignant tumors yielded less than 80% positive cells. The sensitivity of TPO staining for diagnosis of malignancy was thus 100%, its specificity 86.7%, and its overall accuracy 89%. With conventional cytology, sensitivity, specificity, and accuracy were 91.6%, 79.2%, and 81.0%, respectively. We conclude from this study that TPO staining with MoAb47 should become an essential adjunct in the preoperative cytologic diagnosis of thyroid nodules.
Classification of papillary cancer of the thyroid based on prognosis
Authors: Noguchi Shiro , Murakami Nobuo , Kawamoto Hitoshi
Published: October 2004

Between 1965 and 1988 there were 2953 patients with papillary carcinoma treated at Noguchi Thyroid Clinic. Among them 761 patients were excluded because the primary tumor was <10 mm in maximum diameter, the patient's age was >80, or the patient underwent noncurative surgery. The remaining 2192 patients, 192 men and 2000 women, were analyzed. The mean follow‐up period was 12.5 years. Total thyroidectomy, subtotal thyroidectomy, lobectomy with or without isthmectomy, and less than lobectomy were performed in 2.3%, 40.3%, 44.2%, and 13.2%, respectively. Modified radical neck dissection, partial node excision, and no node excision were performed in 77.8%, 6.4%, and 15.8%, respectively. Men and women were separately analyzed because their risk factors and prognosis were significantly different. Multivariate analysis was carried out according to Cox's regression hazard model. Independently significant factors affecting prognosis in men were aged and gross nodal metastasis; and age, gross nodal metastasis,tumor size, and number of adhered tissues or organs were the factors in women. Based on those risk factors patients were classified into three groups. For men, 65.6% were classified in the excellent group and their 10‐year survival was 98.4%; 17.2% were classified as intermediate and 17.2% as poor with survival rates of 90.1% and 74.4%, respectively. For female patients 69.6% were classified in the excellent group, 18.6% in the intermediate group, and 11.9% in the poor group with 10‐year survivals of 99.3%, 96.4%, and 88.8%, respectively.
Presymptomatic screening for medullary thyroid carcinoma in patients with multiple endocrine neoplasia type 2A
Authors: Frilling Andrea , Röher Hans‐Dietrich , John Ponder Bruce Anthony
Published: October 2004

Presymptomatic screening of medullary thyroid carcinoma in MEN IIA families enables the early diagnosis of this tumor with its significant morbidity. Biochemical screening consists of basal and stimulated serum calcitonin evaluation. Genetic screening is based on DNA analysis using linked DNA markers. Thyroidectomy at an occult tumor stage may be curative. Calcitonin measurement was carried out in 58 apparently unaffected family members at risk and 11 MEN IIA patients. Calcitonin elevation was detected in nine individuals. All nine underwent thyroidectomy. Histologic examination confirmed medullary thyroid carcinoma in eight patients and in one case C cell hyperplasia. Postoperatively, eight patients (89%) are clinically and biochemically tumor‐free (mean follow‐up 30 months). DNA screening results in one affected family are presented. DNA analysis allowed recognition of one apparently unaffected individual at risk as a MEN IIA gene carrier. One family member at risk was found not to carry the gene and may be excluded from further screening.
CD15 (LeuM1) immunoreactivity: Prognostic factor for sporadic and hereditary medullary thyroid cancer?
Authors: Längle Friedrich , Soliman Thomas , Neuhold Nikolaus , Widhalm Gerold , Niederle Bruno , Roka Sebastian , Kaserer K. , Blauensteiner Wolfgang , Dam Karl , Clodi Martin , Flores Juan , Loidl Almute , Schwarzlmüller Bernhard , Huber Eva , Jahl Gerald , Wamprechtshammer Klaus , Roka Rudolf ,   Study Group on Multiple Endocrine Neoplasia of Austria
Published: October 2004

Patients treated for sporadic and hereditary medullary thyroid carcinoma (MTC) have varying rates of persistent disease, recurrence, and survival. The aim of this study was to correlate the immunoreactivity of the monoclonal antibody CD15 (LeuM1) to initial clinical findings and the outcome of treatment. The primary tumors of 75 patients with sporadic MTC, 7 with hereditary disease, and 3 members of MEN 2A families were studied. Of these subjects 74 (87%) showed no or little immunoreactivity (<15% positive cells; score 0) in most tumors. The remaining 13% had surgery for tumors with more than 15% cells with positive staining (score I). There was no correlation between LeuM1 immunoreactivity and sex, age, and type of MTC. There was, however, a significant correlation with the pTNM classification and UICC staging. The prognosis for patients with score 0 was significantly better than score 1 patients. CD15 immunoreactivity appears to be a predictive factor in sporadic and hereditary MTC. Lymph node dissection seems to be more successful in patients with score 0 tumors than in those with score 1 tumors. The question of reoperation in patients with recurrence of disease (especially with biochemical recurrence or persistence) should be discussed on the basis of CD15 immunoreactivity.
Clinical course of metastatic parathyroid cancer
Authors: Sandelin Kerstin , Tullgren Owe , Farnebo Lars Ove
Published: October 2004

In a retrospective study the clinical course of 40 patients with symptomatic persistent or recurrent parathyroid cancer was analyzed in order to assess the value of aggressive surgical intervention. Recurrence was diagnosed after a median period of 33 months (1–228 months). Twenty‐two patients had locoregional disease, whereas 14 patients had both local and distant spread. The remaining four patients had distant spread. Patients with just locoregional disease were subject to one to nine reoperative procedures. The median survival time from the last operation was 39 months (1–204 months). Eight patients then had no evidence of disease, three were hypercalemic and 9 of 11 had died of parathyroid cancer. Distant spread was demonstrated in 17 of 40 patients. Pulmonary metastases predominated (14 of 17). Surgical excision was performed in 9 of 14 cases. Of these nine, two patients had a subsequent disease‐free interval of 36+ and 72+ months, respectively. One patient was reported hypercalcemic after 84 months, whereas five patients died of cancer between 4 and 60 months after their last surgical exploration. One patient was lost to follow‐up. In all, 21 patients (53%) died of parathyroid cancer. Conspicuous nuclear atypia and frequent mitoses predominated. Image cytometric DNA analysis showed high rates for all three groups (median p90=80%, range 21–98%).
Outcome of 309 patients with metastatic differentiated thyroid carcinoma treated with radioiodine
Authors: Pacini Furio , Cetani Filomena , Miccoli Paolo , Mancusi Francesco , Ceccarelli Claudia , Lippi Francesco , Martino Enio , Pinchera Aldo
Published: October 2004

From 1969 to 1990 there were 309 patients with differentiated thyroid carcinoma (241 papillary and 68 follicular) treated with radioactive iodine for functioning node metastases alone (n=191) or distant metastases (n=118) with or without node metastases. These patients represented 32.7% of 945 patients treated in our institution during the same period. Initial treatment included near‐total thyroidectomy and 131I ablation of postsurgical thyroid residue, followed by L‐thyroxine suppressive therapy. At the end of follow‐up (mean 5.8 years), 146 patients (76.4%) in the group with nodal metastases were considered cured, as assessed by clinical and laboratory evaluation including whole body scan (WBS) and serum thyroglobulin (Tg) levels; 32 patients (16.7%) had persistent disease. Loss of 131I uptake in persistent metastatic lesions occurred in five patients (2.6%), and newly developed distant metastases occurred in eight patients (4.2%). Of the patients with distant metastases, 36.4% were cured by 131I. Distant metastases from papillary carcinomas had a higher cure rate than follicular carcinomas (p<0.01). The metastases of four patients (5.2%) lost the property to take up radioiodine. Lung and bone metastases detectable by WBS but not by radiography were most likely to be cured by 131I. The overall survival at the end of follow‐up was 95.8% in patients with only lymph node metastases and 76.0% in those with distant metastases. Tumor‐related deaths were 3.6% and 23.7%, respectively. Our data indicate that 131I therapy is highly effective in the treatment of lymph node metastases from differentiated thyroid carcinoma. To a variable extent, distant metastases may also benefit from radioiodine therapy, definitive cure being much more likely during the early phase of metastatic involvement.
Surgery for sporadic primary hyperparathyroidism in the elderly
Authors: Öhryall Ulf , Åkerström Göran , Ljunghall Sverker , Lundgren Eva , Juhlin Claes , Rastad Jonas
Published: October 2004

Retrospective analysis has been performed on 108 consecutive patients operated for primary hyperparathyroidism (HPT) at 75 to 85 years of age (mean 79 years). The preperative serum calcium value averaged 2.99 mM, and six patients had hypercalcemic crisis. Psychic disturbances were seen in 60 patients (56%), 40% of whom demonstrated dementia. Skeletal and muscular complaints were registered in 29% and 19%, respectively, and only 6% were overtly asymptomatic. Cardiovascular diseases were presented by 69% of the patients, 13% had diabetes mellitus, and 26% were institutionalized prior to surgery. Bilateral neck exploration disclosed a single adenoma in 69%, which was of the oxyphil cell type in 13%, and water‐clear (n=3) or chief cell hyperplasia in 27%. The total glandular weight averaged 1085 mg. Altogether 72 patients operated on after 1980 demonstrated a perioperative (30‐day) mortality of 1.4%; the corresponding morbidity of 8.7% mainly included infections as well as a vocal cord paralysis in one patient and two incisional hematomas. Analysis for mean 3.1 years postoperatively displayed reversal of hypercalcemia in 95% of the patients; 2.8% of those operated after 1980 had persistent disease. Symptoms seemed to be alleviated in 62%, with a similar rate attained in patients with dementia. Altogether 60 patients died from mainly cardiovascular diseases mean 4.2 years after the operation. Those succumbing the first postoperative year (n=21) showed overrepresentation of cardiac diseases and diabetes mellitus. The results demonstrate prevalent psychic disturcbances, oxyphil adenomas, and multiglandular parathyroid disease in elderly patients with primary HPT and favor rather liberal application of parathyroid surgery among these individuals.
Conserved Region 2.1 of
Escherichia coli
Heat Shock Transcription Factor σ
32
Is Required for Modulating both Metabolic Stability and Transcriptional Activity
Authors: Horikoshi Mina , Yura Takashi , Tsuchimoto Sachie , Fukumori Yoshihiro , Kanemori Masaaki
Published: October 2004

Escherichia coli
heat shock transcription factor σ
32
is rapidly degraded in vivo, with a half-life of about 1 min. A set of proteins that includes the DnaK chaperone team (DnaK, DnaJ, GrpE) and ATP-dependent proteases (FtsH, HslUV, etc.) are involved in degradation of σ
32
. To gain further insight into the regulation of σ
32
stability, we isolated σ
32
mutants that were markedly stabilized. Many of the mutants had amino acid substitutions in the N-terminal half (residues 47 to 55) of region 2.1, a region highly conserved among bacterial σ factors. The half-lives ranged from about 2-fold to more than 10-fold longer than that of the wild-type protein. Besides greater stability, the levels of heat shock proteins, such as DnaK and GroEL, increased in cells producing stable σ
32
. Detailed analysis showed that some stable σ
32
mutants have higher transcriptional activity than the wild type. These results indicate that the N-terminal half of region 2.1 is required for modulating both metabolic stability and the activity of σ
32
. The evidence suggests that σ
32
stabilization does not result from an elevated affinity for core RNA polymerase. Region 2.1 may, therefore, be involved in interactions with the proteolytic machinery, including molecular chaperones.
The
Salmonella
Membrane Protein IgaA Modulates the Activity of the RcsC-YojN-RcsB and PhoP-PhoQ Regulons
Authors: Tierrez Alberto , García-del Portillo Francisco
Published: October 2004

The
Salmonella enterica
serovar Typhimurium membrane protein IgaA and the PhoP-PhoQ two-component system are used by this pathogen to attenuate the intracellular growth rate within fibroblasts. IgaA has also recently been shown to contribute to virulence by exerting tight repression of the RcsC-YojN-RcsB phosphorelay in host tissues. Here we show that loss of repression of the RcsC-YojN-RcsB system, linked to an R188H mutation in the IgaA protein (
igaA1
allele), is accompanied by altered expression of PhoP-PhoQ-activated (
pag
) genes. The changes in gene expression were different depending on the specific
pag
gene analyzed. Thus, transcription of
ugd
, which is required for lipopolysaccharide modification and colanic acid capsule synthesis, was enhanced in the
igaA1
mutant. RcsB and its coregulator RcsA promoted this alteration in a PhoP-PmrA-independent manner. Unlike
ugd
, activation of the RcsC-YojN-RcsB phosphorelay negatively affected the expression of all other
pag
genes tested. In this case, RcsB alone was responsible for this effect. We also found that PhoP, but not PmrA, negatively modulates the expression of
gmm
, a gene required for colanic acid synthesis that is regulated positively by RcsC-YojN-RcsB. Finally, it was observed that the fine regulation of
pag
genes exerted by RcsB requires the RpoS protein and that an active RcsB, but not RcsA, diminishes expression of the
phoP
gene. These data support the hypothesis that in
Salmonella
there is an intimate regulatory circuit between the PhoP-PhoQ and RcsC-YojN-RcsB phosphorelays, which is revealed only when the RcsC-YojN-RcsB signaling route is derepressed. Consistent with the phenotypes observed in fibroblast cells, IgaA is predicted to favor expression of the entire PhoP-PhoQ regulon based on its repression of the RcsC-YojN-RcsB phosphorelay.
Pyruvate Formate Lyase and Acetate Kinase Are Essential for Anaerobic Growth ofEscherichia colion Xylose
Authors: Hasona Adnan , Kim Youngnyun , Healy F. G. , Ingram L. O. , Shanmugam K. T.
Published: October 2004

During anaerobic growth of bacteria, organic intermediates of metabolism, such as pyruvate or its derivatives, serve as electron acceptors to maintain the overall redox balance. Under these conditions, the ATP needed for cell growth is derived from substrate-level phosphorylation. InEscherichia coli, conversion of glucose to pyruvate yields 2 net ATPs, while metabolism of a pentose, such as xylose, to pyruvate only yields 0.67 net ATP per xylose due to the need for one (each) ATP for xylose transport and xylulose phosphorylation. During fermentative growth,E. coliproduces equimolar amounts of acetate and ethanol from two pyruvates, and these reactions generate one additional ATP from two pyruvates (one hexose equivalent) while still maintaining the overall redox balance. Conversion of xylose to acetate and ethanol increases the net ATP yield from 0.67 to 1.5 per xylose. AnE. coli pflmutant lacking pyruvate formate lyase cannot convert pyruvate to acetyl coenzyme A, the required precursor for acetate and ethanol production, and could not produce this additional ATP.E. coli pflmutants failed to grow under anaerobic conditions in xylose minimal medium without any negative effect on their survival or aerobic growth. AnackAmutant, lacking the ability to generate ATP from acetyl phosphate, also failed to grow in xylose minimal medium under anaerobic conditions, confirming the need for the ATP produced by acetate kinase for anaerobic growth on xylose. Since arabinose transport by AraE, the low-affinity, high-capacity, arabinose/H+symport, conserves the ATP expended in pentose transport by the ABC transporter, bothpflandackAmutants grew anaerobically with arabinose. AraE-based xylose transport, achieved after constitutively expressingaraE, also supported the growth of thepflmutant in xylose minimal medium. These results suggest that a net ATP yield of 0.67 per pentose is only enough to provide for maintenance energy but not enough to support growth ofE. coliin minimal medium. Thus, pyruvate formate lyase and acetate kinase are essential for anaerobic growth ofE. colion xylose due to energetic constraints.
Role of CysE in Production of an Extracellular Signaling Molecule in
Providencia stuartii
and
Escherichia coli
: Loss of
cysE
Enhances Biofilm Formation in
Escherichia coli
Authors: Sturgill Gwen , Toutain Christine M. , Komperda John , O'Toole George A. , Rather Philip N.
Published: October 2004

A mini-Tn
5Cm
insertion has been identified that significantly reduced the amount of an extracellular activating signal for a
lacZ
fusion (
cma37
::
lacZ
) in
Providencia stuartii
. The transposon insertion was located immediately upstream of an open reading frame encoding a putative CysE ortholog. The CysE enzyme, serine acetyltransferase, catalyzes the conversion of serine to
O
-acetyl-
l
-serine (OAS). This activating signal was also produced by
Escherichia coli
, and production was abolished in a strain containing a null allele of
cysE
. Products of the CysE enzyme (OAS,
N
-acetyl-
l
-serine [NAS],
O
-acetyl-
l
-threonine, and
N
-acetyl-
l
-threonine) were individually tested for the ability to activate
cma37
::
lacZ
. Only OAS was capable of activating the
cma37
::
lacZ
fusion. The ability of OAS to activate the
cma37
::
lacZ
fusion was abolished by pretreatment at pH 8.5, which converts OAS to NAS. However, the activity of the native signal in conditioned medium was not decreased by treatment at pH 8.5. In contrast, conditioned medium prepared from cells grown at pH 8.5 exhibited a 4- to 10-fold-higher activity, relative to pH 6.0. Additional genes regulated by the CysE-dependent signal and OAS were identified in
P. stuartii
and
E. coli
. The response to the extracellular signal in
E. coli
was dependent on CysB, a positive activator that requires NAS as a coactivator. In
E. coli
, a
cysE
mutant formed biofilms at an accelerated rate compared to the wild type, suggesting a physiological role for this extracellular signal.
Molecular Identification of the Urea Uptake System and Transcriptional Analysis of Urea Transporter- and Urease-Encoding Genes in
Corynebacterium glutamicum
Authors: Beckers Gabriele , Bendt Anne K. , Krämer Reinhard , Burkovski Andreas
Published: October 2004

The molecular identification of the
Corynebacterium glutamicum
urea uptake system is described. This ABC-type transporter is encoded by the
urtABCDE
operon, which is transcribed in response to nitrogen limitation. Expression of the
urt
genes is regulated by the global nitrogen regulator AmtR, and an
amtR
deletion strain showed constitutive expression of the
urtABCDE
genes. The AmtR repressor protein also controls transcription of the urease-encoding
ureABCEFGD
genes in
C. glutamicum
. The
ure
gene cluster forms an operon which is mainly transcribed in response to nitrogen starvation. To confirm the increased synthesis of urease subunits under nitrogen limitation, proteome analyses of cytoplasmic protein extracts from cells grown under nitrogen surplus and nitrogen limitation were carried out, and five of the seven urease subunits were identified.
The CorA Mg
2+
Transporter Does Not Transport Fe
2+
Authors: Papp Krisztina M. , Maguire Michael E.
Published: October 2004

corA
encodes the constitutively expressed primary Mg
2+
uptake system of most eubacteria and many archaea. Recently, a mutation in
corA
was reported to make
Salmonella enterica
serovar Typhimurium markedly resistant to Fe
2+
-mediated toxicity. Mechanistically, this was hypothesized to be from an ability of CorA to mediate the influx of Fe
2+
. Consequently, we directly examined Fe
2+
transport and toxicity in wild-type versus
corA
cells. As determined by direct transport assay, CorA cannot transport Fe
2+
and Fe
2+
does not potently inhibit CorA transport of
63
Ni
2+
. Mg
2+
can, relatively weakly, inhibit Fe
2+
uptake, but inhibition is not dependent on the presence of a functional
corA
allele. Although excess Fe
2+
was slightly toxic to
S. enterica
serovar Typhimurium, we were unable to elicit a significant differential sensitivity in a wild-type versus a
corA
strain. We conclude that CorA does not transport Fe
2+
and that the relationship, if any, between iron toxicity and
corA
is indirect.
A Novel Archaeal Alanine Dehydrogenase Homologous to Ornithine Cyclodeaminase and μ-Crystallin
Authors: Schröder Imke , Vadas Alexander , Johnson Eric , Lim Sierin , Monbouquette Harold G.
Published: October 2004

A novel alanine dehydrogenase (AlaDH) showing no significant amino acid sequence homology with previously known bacterial AlaDHs was purified to homogeneity from the soluble fraction of the hyperthermophilic archaeon
Archaeoglobus fulgidus
. AlaDH catalyzed the reversible, NAD
+
-dependent deamination of
l
-alanine to pyruvate and NH
4
+
. NADP(H) did not serve as a coenzyme. The enzyme is a homodimer of 35 kDa per subunit. The
K

m

values for
l
-alanine, NAD
+
, pyruvate, NADH, and NH
4
+
were estimated at 0.71, 0.60, 0.16, 0.02, and 17.3 mM, respectively. The
A. fulgidus
enzyme exhibited its highest activity at about 82°C (203 U/mg for reductive amination of pyruvate) yet still retained 30% of its maximum activity at 25°C. The thermostability of
A. fulgidus
AlaDH was increased by more than 10-fold by 1.5 M KCl to a half-life of 55 h at 90°C. At 25°C in the presence of this salt solution, the enzyme was ∼100% stable for more than 3 months. Closely related
A. fulgidus
AlaDH homologues were found in other archaea. On the basis of its amino acid sequence,
A. fulgidus
AlaDH is a member of the ornithine cyclodeaminase-μ-crystallin family of enzymes. Similar to the μ-crystallins,
A. fulgidus
AlaDH did not exhibit any ornithine cyclodeaminase activity. The recombinant human μ-crystallin was assayed for AlaDH activity, but no activity was detected. The novel
A. fulgidus
gene encoding AlaDH, AF1665, is designated
ala
.
The
bcr1
DNA Repeat Element Is Specific to the
Bacillus cereus
Group and Exhibits Mobile Element Characteristics
Authors: Økstad Ole Andreas , Tourasse Nicolas J. , Stabell Fredrik B. , Sundfær Cathrine K. , Egge-Jacobsen Wolfgang , Risøen Per Arne , Read Timothy D. , Kolstø Anne-Brit
Published: October 2004

Bacillus cereus
strains ATCC 10987 and ATCC 14579 harbor a ∼155-bp repeated element,
bcr1
, which is conserved in
B. cereus
,
B. anthracis
,
B. thuringiensis
, and
B. mycoides
but not in
B. subtilis
and
B. licheniformis
. In this study, we show by Southern blot hybridizations that
bcr1
is present in all 54
B. cereus
group strains tested but absent in 11
Bacillus
strains outside the group, suggesting that
bcr1
may be specific and ubiquitous to the
B. cereus
group. By comparative analysis of the complete genome sequences of
B. cereus
ATCC 10987,
B. cereus
ATCC 14579, and
B. anthracis
Ames, we show that
bcr1
is exclusively present in the chromosome but absent from large plasmids carried by these strains and that the numbers of full-length
bcr1
repeats for these strains are 79, 54, and 12, respectively. Numerous copies of partial
bcr1
elements are also present in the three genomes (91, 128, and 53, respectively). Furthermore, the genomic localization of
bcr1
is not conserved between strains with respect to chromosomal position or organization of gene neighbors, as only six full-length
bcr1
loci are common to at least two of the three strains. However, the intergenic sequence surrounding a specific
bcr1
repeat in one of the three strains is generally strongly conserved in the other two, even in loci where
bcr1
is found exclusively in one strain. This finding indicates that
bcr1
either has evolved by differential deletion from a very high number of repeats in a common ancestor to the
B. cereus
group or is moving around the chromosome. The identification of
bcr1
repeats interrupting genes in
B. cereus
ATCC 10987 and ATCC 14579 and the presence of a flanking TTTAT motif in each end show that
bcr1
exhibits features characteristic of a mobile element.
Responses of the
Rhodobacter sphaeroides
Transcriptome to Blue Light under Semiaerobic Conditions
Authors: Braatsch Stephan , Moskvin Oleg V. , Klug Gabriele , Gomelsky Mark
Published: October 2004

Exposure to blue light of the facultative phototrophic proteobacterium
Rhodobacter sphaeroides
grown semiaerobically results in repression of the
puc
and
puf
operons involved in photosystem formation. To reveal the genome-wide effects of blue light on gene expression and the underlying photosensory mechanisms, transcriptome profiles of
R. sphaeroides
during blue-light irradiation (for 5 to 135 min) were analyzed. Expression of most photosystem genes was repressed upon irradiation. Downregulation of photosystem development may be used to prevent photooxidative damage occurring when the photosystem, oxygen, and high-intensity light are present simultaneously. The photoreceptor of the BLUF-domain family, AppA, which belongs to the AppA-PpsR antirepressor-repressor system, is essential for maintenance of repression upon prolonged irradiation (S. Braatsch et al., Mol. Microbiol. 45:827-836, 2002). Transcriptome data suggest that the onset of repression is also mediated by the AppA-PpsR system, albeit via an apparently different sensory mechanism. Expression of several genes, whose products may participate in photooxidative damage defense, including deoxypyrimidine photolyase, glutathione peroxidase, and quinol oxidoreductases, was increased. Among the genes upregulated were genes encoding two σ factors: σ
E
and σ
38
. The consensus promoter sequences for these σ factors were predicted in the upstream sequences of numerous upregulated genes, suggesting that coordinated action of σ
E
and σ
38
is responsible for the upregulation. Based on the dynamics of upregulation, the anti-σ
E
factor ChrR or its putative upstream partner is proposed to be the primary sensor. The identified transcriptome responses provided a framework for deciphering blue-light-dependent signal transduction pathways in
R. sphaeroides
.
Global Transcriptome Analysis of the Heat Shock Response of
Shewanella oneidensis
Authors: Gao Haichun , Wang Yue , Liu Xueduan , Yan Tingfen , Wu Liyou , Alm Eric , Arkin Adam , Thompson Dorothea K. , Zhou Jizhong
Published: October 2004

Shewanella oneidensis
is an important model organism for bioremediation studies because of its diverse respiratory capabilities. However, the genetic basis and regulatory mechanisms underlying the ability of
S. oneidensis
to survive and adapt to various environmentally relevant stresses is poorly understood. To define this organism's molecular response to elevated growth temperatures, temporal gene expression profiles were examined in cells subjected to heat stress by using whole-genome DNA microarrays for
S. oneidensis
. Approximately 15% (
n
= 711) of the total predicted
S. oneidensis
genes (
n
= 4,648) represented on the microarray were significantly up- or downregulated (
P
< 0.05) over a 25-min period after shift to the heat shock temperature. As expected, the majority of the genes that showed homology to known chaperones and heat shock proteins in other organisms were highly induced. In addition, a number of predicted genes, including those encoding enzymes in glycolysis and the pentose cycle, serine proteases, transcriptional regulators (MerR, LysR, and TetR families), histidine kinases, and hypothetical proteins were induced. Genes encoding membrane proteins were differentially expressed, suggesting that cells possibly alter their membrane composition or structure in response to variations in growth temperature. A substantial number of the genes encoding ribosomal proteins displayed downregulated coexpression patterns in response to heat stress, as did genes encoding prophage and flagellar proteins. Finally, a putative regulatory site with high conservation to the
Escherichia coli
σ
32
-binding consensus sequence was identified upstream of a number of heat-inducible genes.
Long-Term Effect of Mutagenic DNA Repair on Accumulation of Mutations in
Pseudomonas syringae
B86-17
Authors: Zhang Shouan , Sundin George W.
Published: October 2004

Forty replicate lineages of
Pseudomonas syringae
B86-17 cells expressing the
rulAB
mutagenic DNA repair (MDR) determinant or the
rulB
::Km MDR-deficient mutant GWS242 were passaged through single-cell bottlenecks (60 cycles), with a UV radiation (UVR) exposure given to half of the lineages at the beginning of each cycle. After every 10th bottleneck cycle, single-colony isolates from all 80 lineages were subjected to 39 phenotypic screens, with newly arising mutations detected in 60 and 0% of UVR-exposed or non-UVR-exposed B86-17 lineages, respectively, by the 60th cycle. Cellular fitness, measured as growth rate in a minimal medium, of UVR-exposed lineages of both B86-17 and GWS242 after 60 cycles was not significantly different from that of the ancestral strains. Although UVR exposure and MDR activity increased the occurrence of mutations in cells, a significant reduction in overall fitness was not observed.
In Vivo Production of Active Nickel Superoxide Dismutase from
Prochlorococcus marinus
MIT9313 Is Dependent on Its Cognate Peptidase
Authors: Eitinger Thomas
Published: October 2004

Metal-dependent superoxide dismutases (SODs) with a specific requirement for a manganese or iron ion for catalytic activity and copper- and zinc-dependent enzymes are essential for detoxification of superoxide anion radicals. Genome sequence analyses predict the existence of a nickel-dependent enzyme (NiSOD) as the unique SOD in oxygen-evolving marine cyanobacteria. NiSOD activity was observed in
Escherichia coli
when
sodN
and
sodX
(encoding a putative peptidase) from
Prochlorococcus marinus
MIT9313 were coexpressed.