Palliative chemotherapy beyond three courses conveys no survival or consistent quality-of-life benefits in advanced non-small-cell lung cancer

This randomised multicentre trial was conducted to establish the optimal duration of palliative chemotherapy in advanced non-small-cell lung cancer (NSCLC). We compared a policy of three vs six courses of new-generation platinum-based combination chemotherapy with regard to effects on quality of life (QoL) and survival. Patients with stage IIIB or IV NSCLC and WHO performance status (PS) 0–2 were randomised to receive three (C3) or six (C6) courses of carboplatin (area under the curve (AUC) 4, Chatelut's formula, equivalent to Calvert's AUC 5) on day 1 and vinorelbine 25 mg m⁻² on days 1 and 8 of a 3-week cycle. Key end points were QoL at 18 weeks, measured with EORTC Quality of Life Questionnaire (QLQ)-C30 and QLQ-LC13, and overall survival. Secondary end points were progression-free survival and need of palliative radiotherapy. Two hundred and ninety-seven patients were randomised (C3 150, C6 147). Their median age was 65 years, 30% had PS 2 and 76% stage IV disease. Seventy-eight and 54% of C3 and C6 patients, respectively, completed all scheduled chemotherapy courses. Compliance with QoL questionnaires was 88%. There were no significant group differences in global QoL, pain or fatigue up to 26 weeks. The dyspnoea palliation rate was lower in the C3 arm at 18 and 26 weeks (P<0.05), but this finding was inconsistent across different methods of analysis. Median survival in the C3 group was 28 vs 32 weeks in the C6 group (P=0.75, HR 1.04, 95% CI 0.82–1.31). One- and 2-year survival rates were 25 and 9% vs 25 and 5% in the C3 and C6 arm, respectively. Median progression-free survival was 16 and 21 weeks in the C3 and C6 groups, respectively (P=0.21, HR 0.86, 95% CI 0.68–1.08). In conclusion, palliative chemotherapy with carboplatin and vinorelbine beyond three courses conveys no survival or consistent QoL benefits in advanced NSCLC.

Validation of a Swedish version of the Cancer Dyspnea Scale

The Cancer Dyspnea Scale (CDS) is a multidimensional measure of dyspnea experience, with three subscales related to sense of effort, sense of anxiety and sense of discomfort, and a total score. In this study, we evaluated the validity and reliability of a Swedish version, the CDS-S, in 99 patients with advanced lung cancer who were not receiving curative or life-prolonging treatments. Criterion-related validity was demonstrated by significant group differences in CDS-S scores when patients were stratified by dyspnea intensity, as measured by a visual analogue scale (VAS-D). Correlations between the total CDS-S score and other dyspnea scales varied between 0.63 and 0.68. Convergent validity was shown by comparing the CDS-S subscales with conceptually related measures of physical and emotional function and discomfort, and correlations ranged from 0.34 to 0.57. The CDS-S captured the psychological dimension of dyspnea better than did the VAS-D. Internal consistency of the CDS-S scales was confirmed by Cronbach's alpha coefficients ranging from 0.81 to 0.90. The CDS-S was well received by the patients and completed in 2 minutes. This study supports the CDS as a valid and reliable instrument to measure dyspnea experience in a palliative setting, well suited for use in research as well as in clinical practice.

A phase I trial of DNA vaccination with a plasmid expressing prostate-specific antigen in patients with hormone-refractory prostate cancer

Prostate-specific antigen (PSA) is a serine protease secreted at low levels by normal luminal epithelial cells of the prostate and in significantly higher levels by prostate cancer cells. Therefore, PSA is a potential target for various immunotherapeutical approaches against prostate cancer. DNA vaccination has been investigated as immunotherapy for infectious diseases in patients and for specific treatment of cancer in certain animal models. In animal studies, we have demonstrated that vaccination with plasmid vector pVAX/PSA results in PSA-specific cellular response and protection against tumour challenge. The purpose of the trial was to evaluate the safety, feasibility and biological efficacy of pVAX/PSA vaccine in the clinic. A phase I trial of pVAX/PSA, together with cytokine granulocyte/macrophage-colony stimulating factor (GM-CSF) (Molgramostim) and IL-2 (Aldesleukin) as vaccine adjuvants, was carried out in patients with hormone-refractory prostate cancer. To evaluate the biologically active dose, the vaccine was administered during five cycles in doses of 100, 300 and 900 μg, with three patients in each cohort. Eight patients were evaluable. A PSA-specific cellular immune response, measured by IFN-γ production against recombinant PSA protein, and a rise in anti-PSA IgG were detected in two of three patients after vaccination in the highest dose cohort. A decrease in the slope of PSA was observed in the two patients exhibiting IFN-γ production to PSA. No adverse effects (WHO grade >2) were observed in any dose cohort. We demonstrate that DNA vaccination with a PSA-coding plasmid vector, given with GM-CSF and IL-2 to patients with prostate cancer, is safe and in doses of 900 μg the vaccine can induce cellular and humoral immune responses against PSA protein.

Cisplatin-based adjuvant chemotherapy in patients with completely resected non-small-cell lung cancer

BACKGROUND

On the basis of a previous meta-analysis, the International Adjuvant Lung Cancer Trial was designed to evaluate the effect of cisplatin-based adjuvant chemotherapy on survival after complete resection of non-small-cell lung cancer.

METHODS

We randomly assigned patients either to three or four cycles of cisplatin-based chemotherapy or to observation. Before randomization, each center determined the pathological stages to include, its policy for chemotherapy (the dose of cisplatin and the drug to be combined with cisplatin), and its postoperative radiotherapy policy. The main end point was overall survival.

RESULTS

A total of 1867 patients underwent randomization; 36.5 percent had pathological stage I disease, 24.2 percent stage II, and 39.3 percent stage III. The drug allocated with cisplatin was etoposide in 56.5 percent of patients, vinorelbine in 26.8 percent, vinblastine in 11.0 percent, and vindesine in 5.8 percent. Of the 932 patients assigned to chemotherapy, 73.8 percent received at least 240 mg of cisplatin per square meter of body-surface area. The median duration of follow-up was 56 months. Patients assigned to chemotherapy had a significantly higher survival rate than those assigned to observation (44.5 percent vs. 40.4 percent at five years [469 deaths vs. 504]; hazard ratio for death, 0.86; 95 percent confidence interval, 0.76 to 0.98; P<0.03). Patients assigned to chemotherapy also had a significantly higher disease-free survival rate than those assigned to observation (39.4 percent vs. 34.3 percent at five years [518 events vs. 577]; hazard ratio, 0.83; 95 percent confidence interval, 0.74 to 0.94; P<0.003). There were no significant interactions with prespecified factors. Seven patients (0.8 percent) died of chemotherapy-induced toxic effects.

CONCLUSIONS

Cisplatin-based adjuvant chemotherapy improves survival among patients with completely resected non-small-cell lung cancer.

Diurnal expression of hetR and diazocyte development in the filamentous non-heterocystous cyanobacterium Trichodesmium erythraeum

The marine non-heterocystous cyanobacterium Trichodesmium fixes atmospheric N(2) aerobically in light. In situ immunolocalization/light microscopy of NifH revealed that lighter, non-granulated cell regions observed correspond to the nitrogenase-containing diazocyte clusters in Trichodesmium IMS101. The number of diazocyte clusters per trichome varied from 0 to 4 depending on trichome length. The constant percentage of diazocytes (approx. 15 %) in cultured strains and five natural populations suggests a developmentally regulated differentiation process. Real-time RT-PCR showed that ntcA, encoding the global nitrogen regulator in cyanobacteria, and hetR, the key regulatory gene in heterocyst differentiation, are both constitutively expressed during a 12 h/12 h light/dark cycle. hetR in addition showed a distinct peak in the dark (close to midnight) while nifH expression commenced 6-8 h later. The expression of all three genes was negatively affected by addition of ammonia. Some early heterocyst differentiation genes were also identified in the genome of Trichodesmium. The data suggest that hetR and ntcA may be required for development and function of diazocytes in Trichodesmium.

Inhibition of cell division blocks the synthesis of the second nitrogenase (Nif2) in the cyanobacterium Anabaena variabilis

Anabaena variabilis ATCC 29413 belongs to the cyanobacteria that use a specific cell type, heterocysts, for fixation of atmospheric nitrogen under aerobic conditions. Nitrogen fixation under anaerobic conditions is catalyzed by a Mo-dependent nitrogenase (Nif2) that is expressed in the vegetative cells. We demonstrate here using immunolocalization/light microscopy (LM) that the synthesis of NifH2 is mainly initiated in dividing vegetative cells along the trichomes. Blocking cell division by cephalexin abolished nitrogenase synthesis under anaerobic conditions.

Physician health, stress and gender at a university hospital

OBJECTIVE

To determine personal and work related factors contributing to physician health and stress in men and women physicians in a university hospital.

METHOD

Mail survey of 161 hospital-based Canadian academic physicians (51 women, 110 men).

RESULTS

Women compared to men, physicians were younger (M = 43 years, S.D. = 7.4 vs. M = 48 years, S.D. = 8.64; P = .001) and fewer had spouses (76% vs. 90%; P = .01) and children (76% vs. 91%; P = .02). A five-item scale measured somatic symptoms, the dependent variable. Among physicians of both gender, the somatic symptoms scale was significantly correlated with satisfaction with amount of time spent working and scales of mental health (five items), work satisfaction (five items), workload (five items), healthy lifestyle (five items), coping abilities (three items) and support-in-stress (two items). On stepwise regression analysis, for women physicians, 70% of the variance in somatic symptoms was explained by support from colleagues when stressed, and workload. For men, 42% of the variance was explained by healthy lifestyle, mental health, support from colleagues when stressed, and workload. Regardless of gender, the majority of physicians reported an excessive workload but the sources of support when stressed varied by gender.

CONCLUSION

Different strategies are needed for women and men physicians to reduce their stress levels.

Colonization of roots of rice (Oryza sativa) by symbiotic Nostoc strains

•   The lack of nitrogen in agriculture, and negative environmental effects of fertilizers, have stimulated interest in creating artificial associations between N₂ -fixing cyanobacteria and rice (Oryza sativa). •   For the first time, numerous (57) Nostoc isolates from natural symbioses were screened for their ability to associate with rice. Successful colonizers were tested for N₂ -fixation by acetylene reduction_, and for their ability to adsorb to roots by chlorophyll a measurements. Paranodules were induced by 2,4-dichlorophenoxyacetic acid. And genetic fingerprints of the cyanobacteria were obtained for identification. Ultrastructural investigations were made by light and scanning electron microscopy. •   Twenty-one symbiotic Nostoc isolates associated with rice roots, colonizing surfaces and intercellular spaces. Adsorption was high and appeared biphasic. The rates of N₂ fixation by associated cyanobacteria were higher compared with those in free-living cyanobacteria. Paranodules were formed and colonized, but root growth was adversely affected. •   Under laboratory conditions, artificial associations were created between one-third of the screened symbiotic cyanobacteria and rice. The agricultural potential for the association appears high since the cyanobacteria adsorb tightly and fix more N₂ than when free-living.

A longitudinal study of the Swedish Self-Evaluation of Communication Experiences after Laryngeal Cancer questionnaire in patients treated for laryngeal cancer

A prospective longitudinal study was performed to investigate the sensitivity to change over time of the Swedish Self-Evaluation of Communication Experiences after Laryngeal Cancer questionnaire (S-SECEL), addressing communication dysfunction in patients with laryngeal cancer. Twenty-six consecutive patients attending a weekly tumour conference over a period of one year at Sahlgrenska University Hospital were included in the study prior to start of treatment. The patients answered four questionnaire repeatedly in the course of one year: the S-SECEL, the European Organization for Research and Treatment of Cancer (EORTC), the Core Quality of Life Core Questionnaire (QLQ-C30) supplemented by the Head and Neck cancer questionnaire module (QLQ-H&N35), and the Hospital Anxiety and Depression (HAD) scale. In addition, performance status was assessed. The S-SECEL questionnaire was well accepted by the patients, and compliance was satisfactory with a cumulative response rate of 88% at one year, supporting its feasibility in clinical settings. Repeated measures with the S-SECEL over one year demonstrated a significant decrease in voice and speech dysfunction. The correlation pattern over time between the S-SECEL and the EORTC and HAD questionnaires lent support to the construct validity of the S-SECEL and indicated that the questionnaire was sensitive to clinical change. The changes in S-SECEL correlated most strongly with changes in the EORTC QLQ-H&N35 speech scale, moderately with changes in the QLQ-C30 role and emotional functioning and global QoL scales, while the weakest correlations were with changes in physical functioning. The S-SECEL was sensitive to changes in communication dysfunction, with convergent and discriminant validity of longitudinal assessments, and with relevance for the quality of life of patients with laryngeal cancer receiving different treatment modalities.

Vision and hearing in old age

The concomitant occurrence of hearing and visual impairment was investigated as part of an epidemiological longitudinal study of elderly people. An age cohort. originally consisting of 973 elderly people, was examined with visual and hearing tests three times at ages 70, 81-82 and 88. The best-corrected visual acuity was assessed. The hearing was measured by pure-tone audiometry and whispered and spoken voice (WSV). At age 70 there was no co-existence of visual and hearing impairments, and about 70% had normal vision and hearing. At 81-82 years 3-6% (WSV and audiometry. respectively) had low vision (VA < or = 0.3) and moderate to severe hearing loss, and more than one-tenth had normal vision and hearing. At 88 years 8-13% had low vision and moderate to severe hearing loss, and none of the men and less than one-tenth of the women had normal vision and hearing. At age 88 three times as many women as men had the combination of low vision and normal hearing. Normal vision with the combination of moderate to severe hearing loss was more often found in 88-year-old men. Mild impairments of the two senses were found in 0.5% at age 70 in 22%, 11% (WSV, audiometry) at age 81-82 and in 23%, 9% at age 88 years. At age 70 there was a statistical correlation between visual acuity and hearing measured with pure-tone audiometry in the male group. Those men with better hearing had slightly better visual capacity than those with hearing loss. No correlations were found for women at age 70 nor for women and men at ages 81-82 and 88. Ophthalmologists and audiology physicians should cooperate closely in the rehabilitation process to reduce disability and improve function and wellbeing among the oldest old.

Long-term clinical outcome of transurethral microwave thermotherapy (TUMT) 1991-1999 at Karolinska Hospital, Sweden

OBJECTIVE

Minimal invasive methods, such as transurethral microwave thermotherapy (TUMT), are economical and have modest side effects compared with transurethral electro-resection of the prostate (TUR-P). The treatment results from different TUMT-systems vary. Follow-up studies on each system type are therefore necessary. The objectives of this study are to summon the long-term clinical results of our TUMT-system and search for a pre-treatment parameter that can measure responding patients.

MATERIAL AND METHODS

Three hundred and seventy-one patients with benign prostate hyperplasia (BPH) were treated with TUMT at Karolinska Hospital, Sweden with the ECP-system (Comair AB, Stockholm), for 30 or 60 min. They were followed up 12 to 72 months after TUMT.

RESULTS

At follow up approximately 76% subjectively judged that they had benefited from the treatment and 22% judged that they were fully cured. The over-all IPSS and Quality of Life score decreased approximately 40% and 30% respectively. Forty-one per cent of the patients with CAD (cathéter à demeure) before the treatment became permanently or temporarily catheter-free after the treatment. Q(max) increased 21% and 11% after 1 and 6 months respectively. Q(max) ranging from over 10 ml/s seem to be a selection parameter that increases the number of responding patients.

CONCLUSION

These long-term clinical data show that TUMT treatment with ECP (electro-coagulation, prostate), gives a good success-rate, with reduction of symptoms. Furthermore there is a good chance of becoming catheter-free after TUMT.

Professional skills and frame of work organization in managing borderline personality disorder. Shared philosophy or ambivalence--a qualitative study from the view of caregivers

Caregivers' experiences and beliefs of working with borderline personality disorder (BPD) in a psychiatric organization were investigated using a qualitative analysis of 29 in-depth interviews. The analysis identified eight characteristics, which were organized in two core concepts. The first of these core concepts, professional skills of mental health work, comprised the categories of empathy for persons with BPD, interest in treating the disorder, feelings of professional frustration and need for a common outlook. The second core concept, frame of work organization, that is categories common to the organization, included ambivalence between the professions of the caregivers, the need for structure in organizing the work, forms of emotional support to the caregivers and the need for a shared philosophy of care. A tentative model was proposed to illustrate the effects of these factors on the type and outcome of work that interact with the care of the patient. It is concluded that ambivalence in the division of labour may be a critical hindrance to the development of cooperation in the care of BPD patients. It is suggested that a shared common philosophy will support corresponding ethical standards by individual practitioners for the benefit of patient outcome.

Characterization of Trichodesmium spp. by genetic techniques

The genetic diversity of Trichodesmium spp. from natural populations (off Bermuda in the Sargasso Sea and off North Australia in the Arafura and Coral Seas) and of culture isolates from two regions (Sargasso Sea and Indian Ocean) was investigated. Three independent techniques were used, including a DNA fingerprinting method based on a highly iterated palindrome (HIP1), denaturing gradient gel electrophoresis of a hetR fragment, and sequencing of the internal transcribed spacer (ITS) of the 16S-23S rDNA region. Low genetic diversity was observed in natural populations of Trichodesmium spp. from the two hemispheres. Culture isolates of Trichodesmium thiebautii, Trichodesmium hildebrandtii, Trichodesmium tenue, and Katagnymene spiralis displayed remarkable similarity when these techniques were used, suggesting that K. spiralis is very closely related to the genus TRICHODESMIUM: The largest genetic variation was found between Trichodesmium erythraeum and all other species of Trichodesmium, including a species of KATAGNYMENE: Our data obtained with all three techniques suggest that there are two major clades of Trichodesmium spp. The HIP1 fingerprinting and ITS sequence analyses allowed the closely related species to be distinguished. This is the first report of the presence of HIP1 in marine cyanobacteria.

Vertebral osteomyelitis in Göteborg, Sweden: a retrospective study of patients during 1990-95

Vertebral osteomyelitis (VO) is a rare condition and the diagnosis is often overlooked initially. Delay in diagnosis may result in vertebral destruction or perforation of the spinal canal. We suggest diagnostic criteria in order to simplify the diagnosis and classification of VO. Medical records of 58 patients with VO from Göteborg during the years 1990-95 were studied retrospectively. The incidence, clinical presentation, microbiology and treatment of VO were evaluated. The median age at the time of admission was 59 y (range 13-83 y) and the male:female ratio was 1.6:1. The incidence was 2.2/100,000 inhabitants/y. Sixty-four percent of the patients were natives of Sweden. The patients were classified as definite (67%), probable (26%) and possible (7%) VO. Staphylococcus aureus was the most common infective agent (34%), followed by Mycobacterium tuberculosis (27%). The most common risk factors included recent or current infections, immunosuppressive diseases and previous surgery. CRP and ESR were elevated in 82% and 88% respectively and plain X-ray changes indicating VO were found in 56% of the patients. Radiological changes were found in 34/44 (77%) computerized tomography scans and 10/13 (77%) magnetic resonance imaging examinations. The median duration of intravenous and oral antibiotic treatment were 10 and 179 d respectively. A delay of > I month from the onset of symptoms until diagnosis was found in 38% of the patients. This indicates the need for a standardized protocol for diagnosing VO. In this paper we suggest diagnostic criteria, which have not previously been available.

Fewer bacterial relapses after oral treatment with norfloxacin than with ceftibuten in acute pyelonephritis initially treated with intravenous cefuroxime

This double-blind, multicentre study was performed at nine centres on a total of 171 patients who presented with fever (> 38.5 degrees C) and signs of acute pyelonephritis. All were initially treated with intravenous cefuroxime. After 2-3 d, when the fever had subsided and urinary culture had revealed growth of Gram-negative bacteria ( > 10(7) colony-forming units per litre), treatment was changed to oral administration of ceftibuten 200 mg b.i.d. or norfloxacin 400 mg b.i.d. for 10 d. The patients were followed for signs of bacterial or clinical relapse 7-14 d after the end of treatment. The initial clinical and bacteriological cure was excellent in both groups, but there were significantly fewer bacterial relapses after oral treatment with norfloxacin than with ceftibuten in acute febrile pyelonephritis initially treated with intravenous cefuroxime. The causal strain was eradicated in 75% of patients (73% of males, 76% of females) in the ceftibuten group and in 89% of patients (94% of males, 85% of females) in the norfloxacin group. The relative frequency of eradication was 0.84 (p < 0.05; 95%, confidence interval 0.74-0.97). Adverse events were reported by 47% of the patients in the ceftibuten group and by 38% in the norfloxacin group. This difference was not significant, but diarrhoea or loose stools occurred more frequently in the ceftibuten group.

Segregation of nitrogen fixation and oxygenic photosynthesis in the marine cyanobacterium Trichodesmium

In the modern ocean, a significant amount of nitrogen fixation is attributed to filamentous, nonheterocystous cyanobacteria of the genus Trichodesmium. In these organisms, nitrogen fixation is confined to the photoperiod and occurs simultaneously with oxygenic photosynthesis. Nitrogenase, the enzyme responsible for biological N2 fixation, is irreversibly inhibited by oxygen in vitro. How nitrogenase is protected from damage by photosynthetically produced O2 was once an enigma. Using fast repetition rate fluorometry and fluorescence kinetic microscopy, we show that there is both temporal and spatial segregation of N2 fixation and photosynthesis within the photoperiod. Linear photosynthetic electron transport protects nitrogenase by reducing photosynthetically evolved O2 in photosystem I (PSI). We postulate that in the early evolutionary phase of oxygenic photosynthesis, nitrogenase served as an electron acceptor for anaerobic heterotrophic metabolism and that PSI was favored by selection because it provided a micro-anaerobic environment for N2 fixation in cyanobacteria.

EAU guidelines for the management of urinary and male genital tract infections. Urinary Tract Infection (UTI) Working Group of the Health Care Office (HCO) of the European Association of Urology (EAU)

A short version of the UTI Guidelines elaborated by the Urinary Tract Infection Working Group of the Health Care Office of the European Association of Urology is presented. The topics include classification, diagnosis, treatment and follow-up of uncomplicated UTI, UTI in children, UTI in diabetes mellitus, renal insufficiency, renal transplant recipients and immunosuppression, complicated UTI due to urological disorders, sepsis syndrome, urosepsis, urethritis, prostatitis, epididymitis, orchitis and principles of perioperative prophylaxis in urology.

Cloning and characterization of the human and rat islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP) genes

Islet-specific glucose-6-phosphatase (G6Pase) catalytic subunit-related protein (IGRP) is a homolog of the catalytic subunit of G6Pase, the enzyme that catalyzes the terminal step of the gluconeogenic pathway. Its catalytic activity, however, has not been defined. Since IGRP gene expression is restricted to islets, this suggests a possible role in the regulation of islet metabolism and, hence, insulin secretion induced by metabolites. We report here a comparative analysis of the human, mouse, and rat IGRP genes. These studies aimed to identify conserved sequences that may be critical for IGRP function and that specify its restricted tissue distribution. The single copy human IGRP gene has five exons of similar length and coding sequence to the mouse IGRP gene and is located on human chromosome 2q28-32 adjacent to the myosin heavy chain 1B gene. In contrast, the rat IGRP gene does not appear to encode a protein as a result of a series of deletions and insertions in the coding sequence. Moreover, rat IGRP mRNA, unlike mouse and human IGRP mRNA, is not expressed in islets or islet-derived cell lines, an observation that was traced by fusion gene analysis to a mutation of the TATA box motif in the mouse/human IGRP promoters to TGTA in the rat sequence. The results provide a framework for the further analysis of the molecular basis for the tissue-restricted expression of the IGRP gene and the identification of key amino acid sequences that determine its biological activity.

Health-Related Quality of Life in Patients With Laryngeal Cancer: A Post-Treatment Comparison of Different Modes of Communication

INTRODUCTION

The effects of different treatment modalities and voice and speech rehabilitation methods on the quality of life in patients with laryngeal cancer are not fully understood.

MATERIALS AND METHODS

A cross-sectional post-treatment questionnaire survey of 125 patients with laryngeal cancer was performed. The response rate was 74%. Three patient groups were identified: patients treated with radiotherapy and communicating with preserved larynx (n = 70), laryngectomized patients using a tracheoesophageal prosthesis (TEP) for speech (n = 14), and laryngectomized patients communicating with an electrolarynx (n = 5). Two established generic questionnaires, the Sickness Impact Profile (SIP) and the Hospital Anxiety and Depression (HAD) scale, were used.

RESULTS

The radiotherapy and the TEP groups displayed similar SIP and HAD profiles. No significant differences were seen in favor of the radiotherapy group, whereas the TEP group reported fewer problems in the SIP sleep/rest subscale. In 10 of 12 SIP categories, the numerically highest proportion of patients with clinically important dysfunction (SIP scores >10) was found in the small electrolarynx group.

CONCLUSION

Successful speech rehabilitation with a TEP after laryngectomy may be as effective as conservative treatment with radiotherapy for laryngeal cancer with regard to psychosocial adjustment and functional ability, as measured with generic quality of life instruments.

Tansley Review No. 116: Cyanobacterium-plant symbioses

Cyanobacteria are an ancient, morphologically diverse group of prokaryotes with an oxygenic photosynthesis. Many cyanobacteria also possess the ability to fix N₂ . Although well suited to an independent existence in nature, some cyanobacteria occur in symbiosis with a wide range of hosts (protists, animals and plants). Among plants, such symbioses have independently evolved in phylogenetically diverse genera belonging to the algae, fungi, bryophytes, pteridophytes, gymnosperms and angiosperms. These are N₂ -fixing symbioses involving heterocystous cyanobacteria, particularly Nostoc, as cyanobionts (cyanobacterial partners). A given host species associates with only a particular cyanobiont genus but such specificity does not extend to the strain level. The cyanobiont is located under a microaerobic environment in a variety of host organs and tissues (bladder, thalli and cephalodia in fungi; cavities in gametophytes of hornworts and liverworts or fronds of the Azolla sporophyte; coralloid roots in cycads; stem glands in Gunnera). Except for fungi, the hosts form these structures ahead of the cyanobiont infection. The symbiosis lasts for one generation except in Azolla and diatoms, in which it is perpetuated from generation to generation. Within each generation, multiple fresh infections occur as new symbiotic tissues and organs develop. The symbioses are stable over a wide range of environmental conditions, and sensing-signalling between partners ensures their synchronized growth and development. The cyanobiont population is kept constant in relation to the host biomass through controlled initiation and infection, nutrient supply and cell division. In most cases, the partners have remained facultative, with the cyanobiont residing extracellularly in the host. However, in the water-fern Azolla and the freshwater diatom Rhopalodia the association is obligate. The cyanobionts occur intracellularly in diatoms, the fungus Geosiphon and the angiosperm Gunner a. Close cell-cell contact and the development of special structures ensure efficient nutrient exchange between the partners. The mobile nutrients are normal products of the donor cells, although their production is increased in symbiosis. Establishment of cyanobacterial-plant symbioses differs from chloroplast evolution. In these symbioses, the cyanobiont undergoes structural-functional changes suited to its role as provider of fixed N rather than fixed C, and the level of intimacy is far less than that of an organelle. This review provides an updated account of cyanobacterial-plant symbioses, particularly concerning developments during the past 10 yr. Various aspects of these symbioses such as initiation and development, symbiont diversity, recognition and signalling, structural-functional modifications, integration, and nutrient exchange are reviewed and discussed, as are evolutionary aspects and the potential uses of cyanobacterial-plant symbioses. Finally we outline areas that require special attention for future research. Not only will these provide information of academic interest but they will also help to improve the use of Azolla as green manure, to enable us to establish artificial N₂ -fixing associations with cereals such as rice, and to allow the manipulation of free-living cyanobacteria for photobiological ammonia or hydrogen production or for use as biofertilizers. contents Summary 449 I. introduction 450 II. the partners 451 III. initiation and development of symbioses 458 IV. the symbioses 462 V. evolutionary aspects 472 VI. artificial symbioses 474 VII. future outlook and perspectives 475 Acknowledgements 477 References 477.