The appendix "mucocoele" misnomer: radiological terminology of "likely appendix mucinous neoplasm" better reflects pathology findings.

AIM: To review the radiological terminology used to describe dilated mucin-containing appendiceal lesions with correlation to the histopathological diagnosis. MATERIALS AND METHODS: Radiology and histopathology reports for all patients with an abnormally dilated appendix referred to a tertiary peritoneal malignancy centre, between January 2021 and December 2021, were reviewed. RESULTS: Overall, 213 patients were included with a median appendiceal diameter of 25.5 mm (range 10-125 mm). Peritoneal disease was present in 109 patients, with the remaining 104 cases demonstrating a dilated appendix only. Local radiology reports were available for 201 cases with the appendix described in 168 cases as appendiceal mucocoele (n=104), appendiceal neoplasm (n=40), appendicitis (n=18), and dilated appendix (n=6). The appendix was not mentioned in 33/201 (15%), either misinterpreted as other pathology (n=15) or not reported (n=18). Peritoneal malignancy histopathology reports were available in 188 cases and reported as low-grade appendix mucinous neoplasm (LAMN, n=144), high-grade appendix mucinous neoplasm (HAMN, n=13), LAMN with foci of HAMN (n=2), LAMN with neuroendocrine tumour (n=2), LAMN with goblet cell adenocarcinoma (n=1), goblet cell adenocarcinoma (n=8), mucinous adenocarcinoma (n=14), non-mucinous adenocarcinoma (n=1), and benign histology (n=3). Only one case of a true inflammatory "mucocoele"/retention cyst was reported. CONCLUSION: In this cohort of patients, the overwhelming majority of dilated, mucin-filled appendices contained malignant cells and benign mucin-filled appendices were rare. The present authors advocate that the term "likely appendix mucinous neoplasm" should replace "appendix mucocoele" to represent the most likely pathology and facilitate less ambiguous interpretation in management decisions.

Not all abdominal masses after colorectal cancer surgery are malignant: intra-abdominal fibromatosis masquerading as recurrence.

AIM: Intra-abdominal fibromatosis is an unusual mesenchymal tumour that can be locally aggressive without any metastatic potential. Fibromatosis may simulate cancer recurrence on imaging surveillance for colorectal cancer follow-up. The optimal treatment of recurrent peritoneal malignancy is cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Confirmatory biopsy of lesions suspicious for colorectal cancer recurrence may not be feasible, thereby rendering surgery the safest option. Our aim was to determine the incidence of fibromatosis in a cohort of patients undergoing CRS and HIPEC for suspected colorectal cancer recurrence. METHODS: One hundred and seventy-one CRS and HIPEC cases were performed at our Peritoneal Malignancy Institute between February 2007 and October 2018 for colorectal peritoneal metastases and were included in a prospectively maintained database. RESULTS: A total of 49 (29%) of 171 cases were performed for primary colorectal cancer with peritoneal metastases, whereas 122 (71%) of 171 cases were performed for suspected colorectal cancer recurrence detected on surveillance imaging after primary colorectal cancer resection. On histological analysis of the resected specimen, five (4.1%) of 122 cases undergoing CRS and HIPEC for colorectal recurrence had fibromatosis. CONCLUSION: Fibromatosis can masquerade as colorectal cancer recurrence. In this series it occurred with an incidence of 4.1% among a cohort of patients undergoing CRS and HIPEC for probable recurrence. Surgical resection may be the only option to confirm the diagnosis and rule out malignancy.

Cytoreductive surgery in combination with hyperthermic intraperitoneal chemotherapy improves survival in patients with colorectal peritoneal metastases compared with systemic chemotherapy alone.

BACKGROUND: Colorectal cancer peritoneal metastasis (CPM) confers an exceptionally poor prognosis, and traditional treatment involving systemic chemotherapy (SC) is largely ineffective. Cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) is increasingly advocated for selected patients with CPM; however, opinions are divided because of the perceived lack of evidence, high morbidity, mortality, and associated costs for this approach. As there is no clear consensus, the aim of this study was to compare outcomes following CRS+HIPEC vs SC alone for CPM using meta-analytical methodology, focusing on survival outcomes. Secondary outcomes assessed included morbidity, mortality, quality of life (QOL), and health economics (HE). METHODS: An electronic literature search was conducted to identify studies comparing survival following CRS+HIPEC vs SC for CPM. The odds ratio (OR) was calculated using the Mantel-Haenszel method with corresponding 95% confidence intervals (CI) and P-values. Heterogeneity was examined using the Q-statistic and quantified with I(2). The fixed-effect model (FEM) was used in the absence of significant heterogeneity. For included studies, 2- and 5-year survival was compared for CRS+HIPEC vs SC alone. RESULTS: Four studies (three case-control, one RCT) provided comparative survival data for patients undergoing CRS+HIPEC (n=187) vs SC (n=155) for CPM. Pooled analysis demonstrated superior 2-year (OR 2.78; 95% CI 1.72-4.51; P=0.001) and 5-year (OR 4.07; 95% CI 2.17-7.64; P=0.001) survival with CRS+HIPEC compared with SC. Mortality ranged from 0 to 8%. No data were available for the assessment of QOL or HE. CONCLUSIONS: Although limited by between-study heterogeneity, the data support the assertion that in carefully selected patients, multimodal treatment of CPM with CRS+HIPEC has a highly positive prognostic impact on medium- and long-term survival compared with SC alone. There is a paucity of comparative data available on morbidity, QOL, and HE.

Primary cutaneous nodular amyloidosis associated with psoriasis.

Primary cutaneous nodular amyloidosis (PCNA) presents as solitary or multiple firm, waxy nodules with a predilection for acral areas. Histologically, PCNA can be identical to myeloma-associated systemic amyloidosis with monoclonal immunoglobulin light chain deposits. We describe a patient in whom PCNA developed in a scar in an area affected by chronic plaque psoriasis. PCNA has previously been associated with other autoimmune diseases, but to our knowledge, this is the first association with psoriasis. Interestingly, T helper (Th)17 cells, which are crucial in psoriasis pathogenesis, have recently been implicated in promotion of myeloma and plasma cell dyscrasias. The association of psoriasis and plasma-cell light chain production in the skin, as in this case, suggests a possible role for Th17 cells in PCNA formation. The dermatopathological literature of this rare but important disease is discussed.

External multicentre validation of pseudomyxoma peritonei PSOGI-Ki67 classification.

BACKGROUND: Pseudomyxoma peritonei (PMP) is a rare malignant disease. Adding of the Ki67 proliferation index to the PSOGI PMP classification provided two different subcategories of the extensive HG-PMP group (HG-PMP ≤15% and HG-PMP >15%) with different survival in a previous unicentric study. This study aims to carry out an external and multicentre validation of this new proposed classification. METHOD: It was a prospective analysis of samples from a historical and international cohort of patients. A representative area with higher cellular density was used to determine the Ki67%. The Ki67 proliferation index (%) was determined in all the HG-PMP patients. A Cox proportional hazard models and multivariable COX models were used. The Kaplan-Meier method and the two-tailed log-rank test were used to analyse the effect of different PSOGI-Ki67 categories on OS and DFS. Its predictive accuracy was analysed using Harrel's C-index and the ROC curve. The calibration was performed using the calibration plots matching. RESULTS: After exclusions, 349 patients were available for analysis. The 5-years OS were 86% for LG-PMP, 59% for HG-PMP≤15, 38% for HG-PMP>15 and 42% for SRC-PMP (p = 0.0001). The 5-years DFS were 49% for LG-PMP, 35% for HG-PMP≤15, 16% for HG-PMP>15 and 18% SRC-PMP (p = 0.0001). The discrimination capability of PSOGI-Ki67 was validated. CONCLUSION: the PSOGI-Ki67 classification discriminates and predicts the OS and DFS in patients with PMP dividing the HG-PMP category into two well-defined sub-categories. The Ki67 proliferation index should be incorporated routinely in the pathology report for these patients.

Multivisceral resection for primary locally advanced rectal carcinoma.

BACKGROUND: Pelvic multivisceral resection offers the possibility of cure in patients with locally advanced rectal cancer. This study assessed the clinical outcome and determinants of survival and local recurrence in patients undergoing multivisceral resection for clinical T4 primary rectal cancer. METHODS: This was a cohort study of consecutive multivisceral resections carried out in a single centre from 2000 to 2009. Determinants of local recurrence and survival were examined by means of Kaplan-Meier survival curves and Cox regression analysis. RESULTS: The study included 42 patients, with a median age of 62 (range 41-83) years, who underwent surgery with a median follow-up of 30 (range 2-102) months. Thirty-one patients had preoperative chemoradiotherapy. Seven patients had rectal resection with en bloc radical prostatectomy. The 30-day mortality rate was zero. Thirty-nine of the 42 patients had a negative circumferential resection margin. The 5-year overall survival rate for those who had complete resection was 48 per cent. Local recurrence was predicted by metastatic disease (P < 0.001) and nodal disease (P < 0.001), but not positive resection margins (P = 0.077). CONCLUSION: An aggressive surgical strategy with complete resection is predictive of long-term survival in selected patients with T4a rectal carcinoma. With optimal treatment local recurrence is a sign of systemic disease.

CXCR3 ligands promote expression of functional indoleamine 2,3-dioxygenase in basal cell carcinoma keratinocytes.

BACKGROUND: Basal cell carcinoma (BCC) is the most common malignancy in humans worldwide. Studies suggest that BCCs exhibit immunoprotection, similar to other keratinocyte carcinomas, although the mechanisms of defence have not been defined. OBJECTIVES: To examine if indoleamine 2,3-dioxygenase (IDO), an immune privilege-associated enzyme, would be expressed in BCC, regulated in part by CXCR3. METHODS: We analysed the expression and function of IDO in human BCC (hBCC) tissues using nonlesional skin epithelial (NL) tissues as a control. RESULTS: Quantitative real-time reverse transcription-polymerase chain reaction (qPCR) revealed significant upregulation of IDO1 and IDO2 (12·5- and 19·14-fold change, respectively) in nodular hBCCs as compared with NL tissues. Immunohistochemistry showed that IDO colocalized with keratin 17, a BCC keratinocyte marker, in hBCC tissues. Western blot identified a full-length IDO (42 kDa) product and a splice variant (∼30 kDa) in BCC tissues. Kynurenine assays and qPCR were conducted to determine IDO enzymatic activity in hBCCs in vitro with CXCL11 supplementation, which has previously been shown to be required for the tumour cell growth. Addition of CXCL11 upregulated IDO2 and increased l-kynurenine concentration in a dose-dependent manner in hBCCs while normal primary keratinocytes exhibited no response. CONCLUSIONS: The expression of IDO at both mRNA and protein levels in hBCC tissues, the upregulation of IDO2 and the IDO-mediated l-kynurenine production in hBCCs with CXCL11 treatment suggest that functional IDO is synthesized by hBCC tumours and may be used as a method of immunoprotection during tumorigenesis. Also, IDO enzymatic activity may be modulated by CXCR3/CXCL11 signalling in BCCs.

Outcome after restorative proctocolectomy in children and adolescents.

AIM: The results including function and quality of life (QOL) of restorative proctocolectomy (RPC) performed in children and adolescents with ulcerative colitis (UC), familial adenomatous polyposis (FAP) and idiopathic megarectum were determined. METHOD: Twenty-one patients of a median age of 15 (10-17) years underwent RPC between 1995 and 2006. The indication, use of covering ileostomy, morbidity and mortality were recorded. A structured questionnaire was completed by telephone interview to assess long-term function. The Cleveland Clinic Scoring (CCS) System was used for the assessment of faecal incontinence and the modified McMaster proforma for QoL. RESULTS: There was no mortality. At a median follow-up of 65.5 (26-168) months, all patients had an intact pouch. One had a long-standing ileostomy. Median daytime and nocturnal stool frequencies were 4 (2-16) and 0 (0-3). The mean CCS was 1.47, with only one patient scoring more than 10. Eighteen of 20 patients were satisfied with the result; two patients had a worse QoL (McMaster score >8). One patient had a permanent stoma following pouch sepsis and one had symptoms of pouchitis. CONCLUSION: RPC can be performed in children and adolescents with good functional outcome and acceptable QoL.

Outcomes of multicystic peritoneal mesothelioma treatment with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.

BACKGROUND: Multicystic peritoneal mesothelioma (MCPM) is a rare neoplasm, generally considered a borderline malignancy, best treated by cytoreductive surgery (CRS) to remove macroscopic disease, combined with hyperthermic intraperitoneal chemotherapy (HIPEC). Owing to its rarity, little has been published on clinical presentation, clinical behaviour over time, or an optimal treatment approach. METHODS: A prospectively developed peritoneal malignancy database was interrogated for the years 2001-2018. Details on all patients with MCPM as a definitive diagnosis after CRS and HIPEC were analysed, including previous interventions, mode of presentation, surgical treatment, postoperative outcomes, and late follow-up information from abdominal CT and tumour markers. RESULTS: Some 40 patients with MCPM underwent CRS and HIPEC between 2001 and 2018. Of these, 32 presented with abdominal pain, distension or bloating, six patients presented with recurrence following previous surgery at the referring hospitals, and two had coincidental diagnoses during a surgical procedure. CRS involved peritonectomy in all 40 patients. Bowel resection was required in 18 patients, and seven had a temporary stoma. Thirty-eight patients were considered to have undergone a complete macroscopic tumour removal (completeness of cytoreduction CC0), and two had residual tumour nodules less than 2.5 mm in size, classified as CC1. Median duration of follow-up was 65 (range 48-79) months. There were no deaths during follow-up. The Kaplan-Meier-predicted recurrence-free interval was 115.4 months. CONCLUSION: MCPM is a rare peritoneal neoplasm with a heterogeneous pattern of presentation. CRS and HIPEC is an effective management option for this group of patients, with favourable long-term survival.

Clinical and surgical outcomes of patients with peritoneal mesothelioma discussed at a monthly national multidisciplinary team video-conference meeting.

BACKGROUND: Peritoneal mesothelioma (PM) is a rare primary neoplasm of the peritoneum with an increasing incidence worldwide. Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) has shown promise as a treatment strategy. A national PM multidisciplinary team (national PM MDT) video-conference meeting was established in the UK and Ireland in March 2016, aiming to plan optimal treatment, record outcomes and provide evidence for the benefits of centralization. This article reports on the activities and outcomes of the first 2·5 years. METHODS: Between March 2016 and December 2018, patients with PM, referred to peritoneal malignancy centres in Basingstoke, Birmingham, Manchester and Dublin, were discussed by the national PM MDT via video-conference. The MDT was composed of surgeons, radiologists, specialist nurses and pathologists. Patients were considered for CRS and HIPEC if considered fit for surgery and if radiological imaging suggested that complete surgical cytoreduction could be achieved. Morbidity and mortality following surgery were analysed. Survival analysis following MDT discussion was conducted. RESULTS: A total of 155 patients (M : F ratio 0·96) with a mean(s.d.) age of 57(17) years were discussed. To date, 22 (14·2 per cent) have had CRS and HIPEC; the median Peritoneal Cancer Index for the surgical group was 17·0. Complete cytoreduction was achieved in 19 patients. Clavien-Dindo grade I-II complications occurred in 16 patients; there was no grade III-IV morbidity or 30-day in-hospital mortality. The median follow-up for the whole cohort was 18·7 months, and the 2-year survival rate from time of first review at the national PM MDT was 68·3 per cent. CONCLUSION: The centralized national PM MDT was effective at selecting patients suitable for CRS and HIPEC, reporting a good outcome from patient selection.

ANTECEDENTES: El mesotelioma peritoneal (peritoneal mesothelioma, PM) es una neoplasia primaria del peritoneo muy poco frecuente, con una incidencia creciente en todo el mundo. La cirugía citorreductora (cytoreductive surgery, CRS) con quimioterapia intraperitoneal hipertérmica (hyperthermic intraperitoneal chemotherapy, HIPEC) se ha mostrado prometedora como estrategia de tratamiento. En marzo de 2016, se organizó una reunión por videoconferencia del equipo multidisciplinar nacional de PM (national PM multi-Disciplinary Team, MDT) en el Reino Unido e Irlanda, con el objetivo de planificar un tratamiento óptimo, registrar los resultados y proporcionar evidencia de los beneficios de la centralización. Este manuscrito presenta las actividades y los resultados de los primeros 2,5 años. MÉTODOS: Entre marzo de 2016 y diciembre de 2018, 155 pacientes con PM, remitidos a centros de cirugía oncológica peritoneal en Basingstoke, Good Hope Hospital en Birmingham, Christie Hospital en Manchester y Mater Misericordiae en Dublín, fueron discutidos en el National PM MDT a través de una videoconferencia. El MDT estaba compuesto por cirujanos, radiólogos, enfermeras especializadas y patólogos. Los pacientes fueron considerados para CRS e HIPEC si se determinaba que eran aptos para la cirugía y si las imágenes radiológicas sugerían que se podía lograr una citorreducción quirúrgica completa. Se analizó la morbilidad y mortalidad después de la cirugía. Se realizó un análisis de supervivencia tras la discusión en el MDT. RESULTADOS: En total, se discutieron 155 pacientes (tasa varón/mujer 0,96) con una edad media de 57 ± 17 años. Hasta el momento, 22 (14,2%) habían sido sometidos a CRS y HIPEC y la mediana de PCI en el grupo quirúrgico fue de 17,0. La citorreducción completa se logró en 19 (86,4%), las complicaciones de Clavien-Dindo grado I/II ocurrieron en 16/22, sin morbilidad de grado III/IV, ni mortalidad a los 30 días. La mediana de seguimiento fue de 15,0 meses y la supervivencia a los 2 años desde el momento de la revisión en el National PM MDT fue del 66,7%. CONCLUSIÓN: El National PM MDT centralizado fue eficaz en la selección de pacientes adecuados para CRS e HIPEC, presentando un buen resultado a partir de dicha selección.

Novel Role for Phycoerythrin in a Marine Cyanobacterium, Synechococcus Strain DC2.

Cyanobacterial picoplankton contribute substantially to oceanic primary productivity. The colored protein phycoerythrin is the major component of their light-harvesting apparatus. It was found that in Synechococcus strain DC2 a variable proportion of the light energy absorbed by phycoerythrin is lost as autofluorescence and therefore is not passed to a photoreaction center. Phycoerythrin may serve two functionally distinct roles in this organism: as a nitrogen reserve and as a collector of quanta for photosynthesis.

Homology between nucleic acids of blue-green algae and chloroplasts of Euglena gracilis.

Ribosomal RNA from several blue-green algae was hybridized to DNA from Euglena gracilis chloroplasts by the membrane filter procedure. This hydridization was competitive with chloroplast ribosomal RNA and indicates significant genetic homology between blue-green algae and plastids from Euglena gracilis.

Local recurrence after abdomino-perineal resection.

OBJECTIVE: Local recurrence of rectal cancer is a major cause of morbidity and mortality following curative resection. The published rates vary after abdomino-perineal resection (APR) from 5% to 47%. The aim of this study was to evaluate local recurrence following curative APR for low rectal cancer in our unit. METHOD: The medical notes of patients treated between 1st January 1996 and 31st December 2000 were retrieved. Local recurrence was defined as the presence of tumour within the pelvis confirmed by clinical findings, pathological specimen or radiological reports. A curative resection was defined as excision of tumour in the absence of macroscopic metastatic disease and whose resection margins were greater than 1 mm circumferentially and 10 mm distally. Outcomes and survival were compared using Fisher's exact test and Kaplan-Meier method. RESULTS: Two hundred consecutive cases with a diagnosis of rectal cancer were identified of which 139 underwent a curative resection (69.5%). Of these 40 patients (28%) underwent APR with curative intent. Two patients (5%) developed local recurrence at 18 and 24 months respectively. The overall local recurrence rate for all curative rectal cancer surgery, in the same period was 2.6%. Eleven patients have died in the follow-up period of which nine were cancer-related deaths. CONCLUSION: The local recurrence rates achieved with APR were not significantly different from those achieved with restorative operations. Tumours at the ano-rectal junction should not be dissected off the pelvic floor, but radically excised en bloc with the surrounding levator ani, as a cylinder, as originally described by Miles.

A combination of assays reveals biomass differences in biofilms formed by Escherichia coli mutants.

AIMS: The aim of this study was to develop an assay system that can quantify the amount of biomass in biofilms formed by different isogenic mutants of an Escherichia coli K-12 strain. METHODS AND RESULTS: The reported assay, which is based on the BacTiter-Glo assay from Promega, uses bioluminescence to detect the intracellular concentration of ATP, which correlates with viable bacterial cell numbers. The quantitative data obtained with this ATP assay were compared to those obtained with the conventional crystal violet assay. As a qualitative control, scanning electron microscopy was performed. CONCLUSIONS: The ATP assay, the crystal violet assay and scanning electron microscopy yielded similar results for six of the eight strains tested. For the remaining two strains, the images from the scanning electron microscopy confirmed the results from the ATP assay. SIGNIFICANCE AND IMPACT OF THE STUDY: The ATP assay, in combination with other quantitative and qualitative assays, will allow us to perform genetic studies on the regulatory network that underlies the early steps in E. coli biofilm formation.

Hyperplastic polyps of the duodenum: an unusual histological finding.

A 58-year-old man underwent upper gastrointestinal surveillance endoscopy for Barrett's oesophagus. This showed a possible gastric ulcer, although histological examination was normal. Follow-up endoscopy showed white ridges in the distal duodenum and these were subjected to biopsy. Histological examination of the biopsy specimens showed polypoid duodenal mucosa showing features similar to those of a hyperplastic polyp of the colon. In addition, the mucosal surface was focally of gastric surface type. The features were interpreted overall as most likely to represent an unusual form of regenerative change in the setting of previous chronic inflammatory mucosal damage. The case is presented as an unusual histological phenomenon at this site; it would be important not to overdiagnose neoplasia in this situation.

Looking 'back to the future': alumni perceptions of a UK undergraduate medical programme.

The five year Bachelor of Medicine (BM5) programme of the University of Southampton commenced in 1971. In keeping with other medical schools, the Southampton BM5 programme has been involved in a number of incremental curriculum reforms over the years. Complementing the School's annual pre-registration house officer (PRHO) questionnaire, this study of alumni cohorts (2000-2003) sought to investigate further how past graduates view their medical education and whether there are emerging priorities in medical practice. Findings confirm that alumni rate the BM5 highly and generally value the BM5 aims. Considering the impact of the social context on individual well-being and patient care, increased emphasis may need to be placed on preventive medicine, including greater alignment of several curriculum areas with clinical practice.

Resistance of DNA from filamentous and unicellular cyanobacteria to restriction endonuclease cleavage.

Chromosomal DNA from nine species of filamentous cyanobacteria as diverse as Nostoc, Gloeotrichia and Plectonema is suggested to be extensively modified (methylated) by its resistance to cleavage by a number of restriction endonucleases. A remarkably similar pattern of DNA modification in these species contrasts with the known heterogeneity of their type II restriction endonuclease content. In particular, Nostoc PCC 73102, which lacks detectable sequence-specific endonucleases, is shown to possess extensive DNA modification. The use of isoschizomers demonstrates the presence of a methylase in the filamentous strains analogous to the dam enzyme of Escherichia coli. As a preliminary to assessing the significance of the DNA modification, a study of susceptibility to restriction endonuclease cleavage of the genomes of five unicellular cyanobacteria revealed considerable variation between the different strains. The significance of the DNA modification patterns elucidated is discussed in terms of the restriction endonuclease content and cellular differentiation of the relevant cyanobacterial strains.

RNA synthesis and the accumulation of guanine nucleotides during growth shift down in the blue-green alga Anacystis nidulans.

Shift down of growth rate in the blue-green alga Anacystis nidulans by reduction of the incident light intensity produced a reduction in the rate of stable RNA accumulation which was correlated with increased concentrations of three phosphorylated compounds, two of which were identified as guanosine 5'-diphosphate-3'-diphosphate (ppGpp) and guanosine 5'-triphosphate3'-diphosphate (pppGpp). The step also causes a large but transient increase in the concentration of GTP. Stable RNA fails to accumulate for a considerable length of time after the concentrations of ppGpp and pppGpp have fallen, suggesting the involvement of another mechanism in the control of stable RNA accumulation.

Changes in photosynthetic activity in the cyanobacterium Chlorogloea fritschii following transition from dark to light growth.

The cyanobacterium Chlorogloea fritschii loses Photosystem II activity, measured by delayed fluorescence and oxygen evolution, during dark heterotrophic growth, but retains Photosystem I, measured as light induced EPR signals. Following transition to the light, Photosystem II recovers in two stages, the first of which does not require protein synthesis. New Photosystem I reaction centres are not synthesised until after net chlorophyll synthesis has commenced. Carbon dioxide fixation recovery commences immediately, the initial rate being unaffected by chloramphenicol. The recovery of carbon dioxide fixation is not directly related to oxygen evolution rate and is only inhibited slightly by 3-(3,4-dichlorophenyl)-1,1-dimethylurea and 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone.

The retroperitoneal surface in distal caecal and proximal ascending colon carcinoma: the Cinderella surgical margin?

BACKGROUND: Mesorectal margin tumour involvement is a predictor of local recurrence in rectal carcinoma and an indication for postoperative radiotherapy in suitable patients. However, the prevalence of non-peritonealised surgical margin involvement in ascending colon carcinoma is unknown. AIMS: To test the hypothesis that retroperitoneal surgical margin (RSM) tumour involvement occurs in distal caecal and proximal ascending colon carcinoma. METHODS/RESULTS: One hundred right hemicolectomy specimens, removed for adenocarcinoma of the caecum or proximal ascending colon, were studied. During routine specimen dissection, at least one additional tissue block was taken to include the tumour and the RSM. The tumour distance from the RSM was recorded. RSM tumour involvement was present in seven cases (7%). Direct (non-nodal) RSM tumour involvement (five cases) only occurred in posterior or circumferential tumours. CONCLUSIONS: RSM tumour involvement occurs within a considerable number of distal caecal and proximal ascending colon carcinomas. The rate of RSM tumour involvement identified here is similar to a previously published local recurrence rate of 10% in caecal carcinoma, suggesting that RSM tumour involvement may be a predictor of recurrence in these tumours. Therefore, patients with distal caecal or proximal ascending colon carcinoma and RSM tumour involvement may benefit from postoperative radiotherapy.