Efficacy and safety of robotic-assisted surgery in challenging hysterectomies - a single institutional experience.

OBJECTIVE: An increasing number of robotic hysterectomies are being performed and the most common indication is fibroids. Fibroid uterus is common indication for hysterectomy for enlarged uteri. The role of robotic approach for complex pathologies as enlarged uterus is still debatable. The study aimed to analyze the feasibility of robotic hysterectomy in patients with enlarged uteri and the impact of uterine weight on surgical outcomes and on operative time length. PATIENTS AND METHODS: One hundred and thirty-eight patients who underwent robotic hysterectomy for benign indications at the 2nd Division of Obstetrics and Gynecology, Azienda Ospedaliero-Universitaria Pisana, University of Pisa were consecutively enrolled. RESULTS: Data of patients undergoing robotic surgery for benign indications were collected. Patients were stratified in two groups based on their uterine weight, to analyze the effective impact of uterine weight and dimension on surgical performance, operative time and postoperative outcomes. Conversion rate was 0%. Median uterine weight was 615 g (range 400-1900 g). Median total operating time was 131 minutes (range 70-255 minutes). Increase in uterine weight significantly increased operative times (p=0.003) and morcellation time (p=0.001). On the other hand, operative time was just partially influenced by route for removal of the uterus (p=0.085) but significantly affected by uterine weight (p=0.008), previous surgeries (p=0.003) and BMI of the patient (p=0.005). CONCLUSIONS: Robotic hysterectomy is feasible and safe for challenging cases as large uteri. This technique could enable patients with outsized uteri, not suitable for vaginal hysterectomy, to undergo minimally invasive surgery with excellent results. Larger studies to investigate and compare robotic with other surgical approaches for difficult hysterectomies are needed to confirm these data.

Comparison of Anterior and Lateral Approach in Hip Hemiarthroplasty for Femur Neck Fractures in the Elderly: Clinical and Radiographic Outcomes.

Introduction: Many surgical approaches have been described for hip hemiarthroplasty (HHA) treating femur neck fractures (FNFs). Direct lateral approach (DLA) is one of the most used. Today, the direct anterior approach (DAA) has become very attractive, but it seems to involve more intra-operative fractures. Our main endpoint was to demonstrate that the DAA may be a valid alternative comparing to the DLA. Materials and methods: Patients affected by FNFs and treated with HHA between the years 2016 and 2020 were studied. We divided the treatment of the fractures according to the surgical approach. The analysis was focused on perioperative complications and radiological outcomes. Results: There were a total of 166 patients. The DLA group included patients with an average age of 83.5 years and the DAA group of 83 years. We found similar surgical times (DLA 67 min vs DAA 61 min; p = 0,55), number of transfusions (DLA 3/person vs DAA 4/person; p = 0,91), perioperative complications (fractures: DLA 0 vs DAA 0 - dislocations: DLA 2,50% vs DAA 0) and functional outcomes (HHS: DLA 83 points vs DAA 87 points; p = 0,71). There were no statistical differences comparing diaphyseal filling (Canal Fill Index at the proximal third: DLA 0,79 vs DAA 0,78; p= 0,24), bone loss (Paprosky I: DLA 96,25% vs DAA 91,86%; p = 0,47) and prevalence of heterotopic ossification (Broker low degree: DLA 93,75% vs 95, 34%; p = 0,87). Conclusion: Analysing perioperative complications and studying post-operative radiographic evolution, our results suggest that the DAA is a valid alternative to the DLA in HHA treating FNFs.

Comparison of Anterior and Lateral Approach in Hip Hemiarthroplasty for Femur Neck Fractures in the Elderly: Clinical and Radiographic Outcomes

@#Introduction: Many surgical approaches have been described for hip hemiarthroplasty (HHA) treating femur neck fractures (FNFs). Direct lateral approach (DLA) is one of the most used. Today, the direct anterior approach (DAA) has become very attractive, but it seems to involve more intra-operative fractures. Our main endpoint was to demonstrate that the DAA may be a valid alternative comparing to the DLA. Materials and methods: Patients affected by FNFs and treated with HHA between the years 2016 and 2020 were studied. We divided the treatment of the fractures according to the surgical approach. The analysis was focused on perioperative complications and radiological outcomes. Results: There were a total of 166 patients. The DLA group included patients with an average age of 83.5 years and the DAA group of 83 years. We found similar surgical times (DLA 67 min vs DAA 61 min; p = 0,55), number of transfusions (DLA 3/person vs DAA 4/person; p = 0,91), perioperative complications (fractures: DLA 0 vs DAA 0 – dislocations: DLA 2,50% vs DAA 0) and functional outcomes (HHS: DLA 83 points vs DAA 87 points; p = 0,71). There were no statistical differences comparing diaphyseal filling (Canal Fill Index at the proximal third: DLA 0,79 vs DAA 0,78; p= 0,24), bone loss (Paprosky I: DLA 96,25% vs DAA 91,86%; p = 0,47) and prevalence of heterotopic ossification (Broker low degree: DLA 93,75% vs 95, 34%; p = 0,87). Conclusion: Analysing perioperative complications and studying post-operative radiographic evolution, our results suggest that the DAA is a valid alternative to the DLA in HHA treating FNFs.

Safety and efficacy of tigecycline in complicated and uncomplicated pelvic inflammatory disease.

OBJECTIVE: Tigecycline is a glycylcycline antimicrobial structurally related to minocycline, with a wide spectrum of activity that includes anaerobes and typical and atypical microorganisms causing pelvic inflammatory disease (PID). This study aimed to evaluate efficacy and safety of tigecycline in complicated PID and un-complicated PID after the failure of first-line antibiotic therapy. PATIENTS AND METHODS: Between May 2014 and April 2016 at the 2nd Unit of Obstetrics and Gynecology, Santa Chiara Hospital of Pisa a pilot study on 20 women with mild/moderate PID after the failure of first-line antibiotic therapy and on 8 women with complicated PID was conducted. The treatment protocol was 10-day course of tigecycline, with a loading dose of 100 mg intravenously (i.v.) at day one and then 50 mg IV twice daily. The primary endpoint was to evaluate tigecycline's efficacy in terms of clinical response to test-of-cure (TOC) at the end of therapy and 30 days after the last dose. Clinical response during therapy and safety were analyzed as well. RESULTS: A total of 28 women were enrolled, and 25 patients completed the study protocol, because 3 patients reported adverse drug effects resulting in treatment interruption. PID was mainly caused by Chlamydia, Gardnerella, Mycoplasma/Ureaplasma. Tigecycline showed a 100% remission of signs and symptoms in patients resistant to first-line antibiotic regimen and in patients with complicated PID. Moreover, tigecycline showed good tolerability and compliance. CONCLUSIONS: Despite the limited sample size, tigecycline seemed an effective and safe treatment for women with complicated/resistant PID. Nevertheless, further clinical trials are needed to confirm these results.

Holocene sea ice variability driven by wind and polynya efficiency in the Ross Sea.

The causes of the recent increase in Antarctic sea ice extent, characterised by large regional contrasts and decadal variations, remain unclear. In the Ross Sea, where such a sea ice increase is reported, 50% of the sea ice is produced within wind-sustained latent-heat polynyas. Combining information from marine diatom records and sea salt sodium and water isotope ice core records, we here document contrasting patterns in sea ice variations between coastal and open sea areas in Western Ross Sea over the current interglacial period. Since about 3600 years before present, an increase in the efficiency of regional latent-heat polynyas resulted in more coastal sea ice, while sea ice extent decreased overall. These past changes coincide with remarkable optima or minima in the abundances of penguins, silverfish and seal remains, confirming the high sensitivity of marine ecosystems to environmental and especially coastal sea ice conditions.

Ancient population genomics and the study of evolution.

Recently, the study of ancient DNA (aDNA) has been greatly enhanced by the development of second-generation DNA sequencing technologies and targeted enrichment strategies. These developments have allowed the recovery of several complete ancient genomes, a result that would have been considered virtually impossible only a decade ago. Prior to these developments, aDNA research was largely focused on the recovery of short DNA sequences and their use in the study of phylogenetic relationships, molecular rates, species identification and population structure. However, it is now possible to sequence a large number of modern and ancient complete genomes from a single species and thereby study the genomic patterns of evolutionary change over time. Such a study would herald the beginnings of ancient population genomics and its use in the study of evolution. Species that are amenable to such large-scale studies warrant increased research effort. We report here progress on a population genomic study of the Adélie penguin (Pygoscelis adeliae). This species is ideally suited to ancient population genomic research because both modern and ancient samples are abundant in the permafrost conditions of Antarctica. This species will enable us to directly address many of the fundamental questions in ecology and evolution.

Choroid plexus papilloma in a Rottweiler: computed tomographic, gross morfological and histological features / Papiloma do plexo coroide em um cão da raça Rottweiler: aspectos tomográficos, macroscópicos e histológicos

Among the tumors affecting the choroid plexus in dogs, the papilloma ranks second place in incidence after cell carcinoma tumors. Presumptive diagnosis can be made through imaging methods, such as computed tomography and magnetic resonance images. Definitive diagnosis of plexus choroid tumor is based on histopathological findings. This report presented the tomographic features of the brain in a 6-year-old intact female Rottweiler with choroid plexus papilloma. The computed tomography showed right lateral ventricle enlargement, midline deviation and an enhanced mass into the postcontrast phase. At necropsy, a mass on the floor of the right lateral ventricle was observed, associated with important ventricle dilatation. The histopathological analysis demonstrated the presence of neoplastic cell forms with papillary projections. The computed tomography proved to be an effective tool in the presumptive diagnosis of this kind of cerebral disorder.

Dentre os tumores que afetam o plexo coroide em cães, o papiloma figura como o segundo tipo de maior incidência, antecedido apenas pelo carcinoma. O diagnóstico presuntivo pode ser elaborado por meio de métodos de imagem, como a tomografia computadorizada e a ressonância magnética. O diagnóstico definitivo de tumor do plexo coroide é estabelecido com base nos achados histopatológicos. Relatamos os aspectos tomográficos do crânio em uma fêmea de 6 anos, inteira, da raça Rottweiler, com papiloma do plexo coroide. A tomografia computadorizada revelou dilatação do ventrículo lateral direito, desvio da linha média e a presença de uma massa, que sofreu realce na fase pós-contraste. À necropsia, foi observada uma massa sobre o assoalho do ventrículo lateral direito, associada à importante dilatação ventricular. A análise histopatológica demonstrou a presença de células poligonais neoplásicas, arranjadas em papilas longas. A tomografia computadorizada apresentou-se como uma ferramenta eficaz no diagnóstico presuntivo desse tipo de alteração cerebral.

MIH supplementation strategies: prospective clinical and laboratory trial.

The use of calcium-phosphate casein on hypomineralized molars (molar incisor hypomineralization, MIH) has been proposed but not clinically investigated. Qualitative and quantitative effects of supplementation with a calcium-phosphate casein product on MIH molars were monitored over a period of three years. Molar replicas, minimally invasive biopsies and their SEM microphotographs, plus ESEM/EDX semi-quantitative peaks of elements present in affected enamel were evaluated. Mineralization, morphology, and porosity appeared markedly improved, with calcium and phosphate levels reaching almost normal levels at three years' follow-up. The hypothesis tested was rejected, since calcium-phosphate casein improved enamel morphology in vivo.

Consumo e digestibilidade de nutrientes em novilhos suplementados e terminados em pasto, na seca / Intake and digestibility of nutrients in steers supplemented and finished on pasture in the dry season

Avaliaram-se o consumo e a digestibilidade de nutrientes por novilhos Nelore suplementados com elevado teor de proteína na terminação, em pasto, durante a seca. Foram utilizados quatro novilhos com 30 meses e peso médio inicial de 440kg, distribuídos em quadrado latino 4x4 (quatro níveis de suplementação e quatro períodos de 16 dias). Foram usados quatro piquetes de um hectare de capim Panicum maximum cv. Tanzânia, e os animais receberam: 0 (grupo-controle); 1,0; 2,0; ou 4,0kg de suplemento/dia. Os suplementos, à exceção do controle, apresentaram níveis decrescentes de proteína bruta (58 a 32 por cento da matéria seca) e proporções de mistura mineral:ureia:farelos de 10:10:80, 5:5:90 e 2,5:2,5:95 para os respectivos tratamentos. O consumo e a digestibilidade foram determinados com o uso do óxido crômico e FDAi, o delineamento estatístico foi em quadrado latino, e os tratamentos foram avaliados pela análise de regressão. Houve efeito linear crescente sobre o consumo e sobre os coeficientes de digestibilidade da matéria seca, proteína bruta, extrato etéreo e fibra em detergente neutro, e sobre o consumo de nutrientes digestíveis totais. Não houve efeito sobre o consumo de pasto e o consumo e a digestibilidade dos carboidratos não fibrosos. Os suplementos avaliados em geral melhoraram o consumo e a digestibilidade e, consequentemente, o valor nutritivo da dieta de novilhos em terminação sob pastejo, no período da seca.

The effects of supplements with high protein content on intake and digestibility were evaluated in Nellore steers finished at pasture during the dry season. Four steers avering 30-month old and initial weight of 440kg were distributed in a 4x4 Latin square (four levels of supplementation and four periods of 16 days). Four paddocks of one hectare containing Panicum maximum cv. Tanzania grass were utilized and the animals received 1.0, 2.0, or 4.0kg of supplement/day, in addition to a control - mineral mixture. The supplements, except control, presented decreasing levels of crude protein (58 to 32 percent in dry matter) and the proportions of mineral mixture:urea:cereal meals were 10:10:80, 5:5:90, and 2.5:2.5:95 for the treatments. The intake and digestibility were determined with the use of chromium oxide and ADFi. The statistical design was Latin square and the treatments were evaluated by regression analysis. There was an increasing linear effect on the intakes and digestibility coefficients of dry matter, crude protein, ether extract, neutral detergent fiber, and intake of total digestible nutrients. There was no effect on the intake of pasture and intake and digestibility of non-fiber carbohydrates. It can be concluded that the evaluated supplements generally improve the intake and digestibility and consequently the nutritive value of the diets of finishing animals on the pasture during the dry season.

Desempenho de novilhos suplementados e terminados em pasto, na seca, e avaliação do pasto / Performance of steers supplemented and finished on pasture in the dry season and pasture evaluation

Avaliaram-se o ganho de peso e as características de carcaça de novilhos Nelore suplementados com elevado teor de proteína na terminação em pasto, durante a seca, e estimou-se a disponibilidade dos componentes da pastagem. O experimento foi implantado em pastagem de Brachiaria brizantha, cv. Marandu, em seis piquetes de nove hectares. Foram utilizados 48 novilhos Nelore com 30 meses de idade e 415±16 kg. Cada lote, alojado em um piquete, foi pesado no início e a cada 21 dias, durante 84 dias. A suplementação constou de: 0 (grupo-controle); 0,25; 0,5; 1,0; 2,0; ou 4,0 kg/animal/dia. Os suplementos, à exceção do controle, apresentaram porcentagens decrescentes de proteína bruta (111 a 32 por cento da matéria seca) e proporções de mistura mineral:ureia:farelos de 25:25:50; 15:15:70; 10:10:80; 5:5:90 e 2,5:2,5:95, para os respectivos tratamentos. O delineamento foi o inteiramente ao acaso e os tratamentos foram avaliados pela análise de regressão. A proporção de colmo e folha seca aumentou no decorrer dos períodos experimentais, caracterizando o déficit hídrico da estação seca. Houve efeito linear crescente sobre o peso vivo final, ganho médio diário, peso de carcaça, espessura de gordura subcutânea e rendimento de carcaça em função do consumo de suplemento. A conversão do suplemento em kg/kg de ganho de peso, de 10:1, é típica de suplementação energética, mostrando que os animais não responderam satisfatoriamente à suplementação proteica.

Daily gain and carcass traits of Nellore steers fed different levels of supplementation with high content of protein at finishing during the dry season and the availability of the components of the pasture were evaluated. The experiment was carried out on pasture of Brachiaria brizantha, cv. Marandu, in six paddocks of nine hectares. Forty-eight Nellore steers averaging 30-month old and 415+16kg were used. Each group was allocated in a paddock, being weighted in the beginning and every 21 days, during 84 days. The levels of supplements were: 0.25, 0.5, 1.0, 2.0, and 4.0kg/animal/day, in addition to a control (mineral mixture). The supplements, except the control, presented decreasing levels of crude protein (111 to 32 percent of the dry matter) and proportions of mineral mixture:urea:concentrate feeds of 25:25:50, 15:15:70, 10:10:80, 5:5:90, and 2.5:2.5:95, respectively. The statistical design was completely randomized and the treatments were evaluated by regression analysis. The proportion of stem and dead leaf increased in elapsing of the experimental periods characterizing water deficit in the dry season. There was increasing linear effect on the final live weight, average daily gain, carcass weight, fat thickness, and carcass yield as a function of supplement intake. The supplement conversion in kg/kg of weight gain, at 10:1, is typical of energetic supplementation, showing that the animals did not satisfactorily respond to protein supplementation, which would give better values of conversion.

Expression of TCL1 and CD27 in primary cutaneous B-cell lymphomas.

AIMS: To investigate by immunohistochemical analysis the expression of the TCL1 oncogene product and of CD27 in 25 cases of primary cutaneous B-cell lymphomas (PCBCL) classified according to the World Health Organization-European Organization for Research and Treatment of Cancer classification of cutaneous lymphomas. In B-cell ontogenesis TCL1 is mainly expressed by 'naive' B lymphocytes and by a subset of germinal centre B cells, whereas CD27 is expressed by a subset of germinal centre B cells, 'memory' B lymphocytes and plasma cells, suggesting that their expression in physiological conditions is mutually exclusive. METHODS AND RESULTS: Overall, TCL1 was expressed in 5/25 cases (20%) and CD27 in 15/25 cases (60%). Furthermore, 7/25 cases (28%) were TCL1- and CD27- and 2/25 cases (8%) were TCL1+ and CD27+. In particular, primary cutaneous follicle-centre lymphomas (10 cases) showed a variable expression of both TCL1 and CD27, whereas primary cutaneous marginal-zone B-cell lymphomas (eight cases) showed, with the exception of a single case, a definite CD27+/TCL1- profile. CONCLUSIONS: These findings indicate: (i) the TCL1 oncogene product is uncommonly expressed in PCBCL (20% of cases, mainly of the follicle-centre subtype); (ii) in contrast, CD27 is often expressed in PCBCL (60% of cases), mainly of the marginal-zone subtype; (iii) the coexpression of TCL1 and CD27 may be seldom observed in PCBCL (8% of cases); (iv) PCBCL does not seem to show, in terms of either TCL1 or CD27 expression, significant differences compared with its systemic counterparts.

Holocene elephant seal distribution implies warmer-than-present climate in the Ross Sea.

We show that southern elephant seal (Mirounga leonina) colonies existed proximate to the Ross Ice Shelf during the Holocene, well south of their core sub-Antarctic breeding and molting grounds. We propose that this was due to warming (including a previously unrecognized period from approximately 1,100 to 2,300 (14)C yr B.P.) that decreased coastal sea ice and allowed penetration of warmer-than-present climate conditions into the Ross Embayment. If, as proposed in the literature, the ice shelf survived this period, it would have been exposed to environments substantially warmer than present.

[The Haemolymphopathology Italian Group (H.I.G.): an essential resource for the new technical and organization problems troubling modern haemolymphopathology diagnostics]. / II Gruppo Italiano di Emolinfopatologia (G.I.E.): una esigenza per le nuove e complesse problematiche tecnico-organizzative della moderna diagnostica emolinfopatologica.

Recently, many progresses have been recorded in the molecular and histogenetic characterization of the haematopoietic and lymphoid tumours, resulting in important classifying changes. As a consequence, the exact definition of lymphoma subtype requires an integration between traditional morphologic "expertise" and several bio-functional data obtained from advanced and complex ancillary techniques (immunohistochemistry, molecular biology and cytogenetics). At the same time, the data provided by gene expression profiling studies are going to deeply modify the therapies in haematological cancers. These studies are expected to allow the achievement of single-patient-tailored genic therapy; for this reason it is necessary to get biological samples of good quality. Indeed, while these progresses contribute to highlight the pathologist's diagnostic role, they should make us reflect on the state of the art of the Italian haemolymphopathology diagnostics and on its ability to cope up with the new challanges. The aim of this article is to outline a realistic picture of the present condition, and to explain the reasons for setting up, inside SIAPEC-IAP, the Haemolymphopathology Italian Group (H.I.G.). The purpose of H.I.G. will be twofold: first of all, scheduling of a series of projects so as to the haemolymphopathological diagnostic standardization; secondly, building a national network among all the pathologists involved in this exciting and complex field of the anatomic pathology.

Transformation of the entomopathogenic fungus Paecilomyces fumosoroseus with Agrobacterium tumefaciens.

AIMS: To test the suitability of the Agrobacterium tumefaciens-mediated transformation (AMT) method with Paecilomyces fumosoroseus, a fungal pathogen that causes diseases in a wide range of insects including whiteflies. METHODS AND RESULTS: Conidia of P. fumosoroseus were successfully transformed to hygromycin B resistance using the hph gene of Escherichia coli as the selectable marker. Transformation frequencies were 58.3 +/- 18.5, 98.3 +/- 24.8 and 169.7 +/- 35.5 (+/-SEM) transformants per 10(5), 10(6) and 10(7) target conidia respectively. After confirmation by PCR, transformants were subjected to Southern analysis, and the results revealed that 45% (four of nine) of the transformants contained single-copy integration of the T-DNA. CONCLUSIONS: In our AMT system, we efficiently transformed conidia of P. fumosoroseus. The employment of this method circumvents time-consuming protoplast preparation and allows the isolation of transformants containing single-copy integration of the T-DNA. SIGNIFICANCE AND IMPACT OF THE STUDY: Considering the efficiency of Ag. tumefaciens-mediated transformation, this method represents a useful tool for insertional mutagenesis to characterize genes that are important for the pathogenicity of P. fumosoroseus.

Microevolution and mega-icebergs in the Antarctic.

Microevolution is regarded as changes in the frequencies of genes in populations over time. Ancient DNA technology now provides an opportunity to demonstrate evolution over a geological time frame and to possibly identify the causal factors in any such evolutionary event. Using nine nuclear microsatellite DNA loci, we genotyped an ancient population of Adélie penguins (Pygoscelis adeliae) aged approximately 6,000 years B.P. Subfossil bones from this population were excavated by using an accurate stratigraphic method that allowed the identification of individuals even within the same layer. We compared the allele frequencies in the ancient population with those recorded from the modern population at the same site in Antarctica. We report significant changes in the frequencies of alleles between these two time points, hence demonstrating microevolutionary change. This study demonstrates a nuclear gene-frequency change over such a geological time frame. We discuss the possible causes of such a change, including the role of mutation, genetic drift, and the effects of gene mixing among different penguin populations. The latter is likely to be precipitated by mega-icebergs that act to promote migration among penguin colonies that typically show strong natal return.

[Thirty years of nephrology and dialysis in Mantua: results and prospects]. / Trent' anni di nefrologia e dialisi a Mantova Risultati e prospettive.

During the thirty years from its birth, the activity of the Department of Nephrology and Dialysis at the Carlo Poma Hospital in Mantova has witnessed the progressive increase in the number of kidney patients (300/year), uraemic patients in RRT, both peritoneal and extracorporeal (>220 patients) and kidney transplants (84). During the same period there has also been an increase in the following activities: from kidney biopsy by echocolordoppler for glomerular illness to metabolic studies for the prevention of kidney stones, therapy and follow-up for hypertension during pregnancy to echo-studies of the renal vascular bed, long-term follow-up of kidney transplant patients to territorial distribution of 4 limited-care dialysis facilities. Vascular access surgery, 100 interventions per year, and home peritoneal dialysis (CAPD and APD (today more than 50 pts in treatment) are increasing. During the last three years there has been a rapid increased in requests for CRRT in the ICU's. After acknowledging the work of all doctors active throughout the years, this presentation ends with a report on the goals for the near future.

Rates of evolution in ancient DNA from Adélie penguins.

Well-preserved subfossil bones of Adélie penguins, Pygoscelis adeliae, underlie existing and abandoned nesting colonies in Antarctica. These bones, dating back to more than 7000 years before the present, harbor some of the best-preserved ancient DNA yet discovered. From 96 radiocarbon-aged bones, we report large numbers of mitochondrial haplotypes, some of which appear to be extinct, given the 380 living birds sampled. We demonstrate DNA sequence evolution through time and estimate the rate of evolution of the hypervariable region I using a Markov chain Monte Carlo integration and a least-squares regression analysis. Our calculated rates of evolution are approximately two to seven times higher than previous indirect phylogenetic estimates.

p53 over-expression identifies a subset of nodal peripheral T-cell lymphomas with a distinctive biological profile and poor clinical outcome.

Peripheral T-cell lymphomas (PTCL) are usually characterized by aggressive clinical behaviour and poor clinical outcome, but their biological background has not been extensively investigated to date, due to their low incidence, about 10% of all non-Hodgkin's lymphoma cases in Western countries, and also to the paucity of specific molecular-genetic abnormalities. Neverthless, there is increasing biological and clinical evidence that primary nodal PTCL should be considered separately from extra-nodal cases, but little is known about biological factors of possible clinical and prognostic impact. This immunohistochemical study has analysed the expression of p53, Mdm2, p21(WAF1), BCL-2 and p-glycoprotein (MDR-1 gene product) in a series of 45 cases of nodal peripheral T-cell lymphomas (PTCL) with 'high-grade' histology. The immunohistochemical findings were then correlated with proliferative activity and clinical outcome. p53 was over-expressed in 13 cases (28.9%). p53 positive cases showed significantly higher proliferative activity (p<0.01), more frequent expression of Bcl-2 (p<0.01) and less frequent expression of p21(WAF1) than p53 negative cases. Mdm2 and p-glycoprotein were expressed in 4/13 (30.8%) and 8/13 (61.5%) p53 positive cases respectively, and in none (0%) of the p53 negative cases (p<0.01). Analysis of the survival curves showed that p53 positive cases were associated with a significantly poorer clinical outcome than p53 negative cases, in terms of both overall survival (p=0.0032) and event-free survival (p=0.0004). Furthermore, multivariate analysis showed that p53 expression was the most important independent prognostic variable. These findings indicate that p53 over-expression identifies a subset of nodal PTCL cases with a distinctive biological profile (higher proliferative activity, less frequent expression of p21(WAF1) and more frequent expression of Bcl-2, Mdm2 and p-glycoprotein than p53 negative cases) and poor clinical outcome. The immunohistochemical analysis of p53 expression is a simple, rapid and low-cost method which may provide information of potential clinical and prognostic value in nodal peripheral T-cell lymphomas.