Clinical characteristics with inflammation profiling of long COVID and association with 1-year recovery following hospitalisation in the UK: a prospective observational study

BACKGROUND

No effective pharmacological or non-pharmacological interventions exist for patients with long COVID. We aimed to describe recovery 1 year after hospital discharge for COVID-19, identify factors associated with patient-perceived recovery, and identify potential therapeutic targets by describing the underlying inflammatory profiles of the previously described recovery clusters at 5 months after hospital discharge.

METHODS

The Post-hospitalisation COVID-19 study (PHOSP-COVID) is a prospective, longitudinal cohort study recruiting adults (aged ≥18 years) discharged from hospital with COVID-19 across the UK. Recovery was assessed using patient-reported outcome measures, physical performance, and organ function at 5 months and 1 year after hospital discharge, and stratified by both patient-perceived recovery and recovery cluster. Hierarchical logistic regression modelling was performed for patient-perceived recovery at 1 year. Cluster analysis was done using the clustering large applications k-medoids approach using clinical outcomes at 5 months. Inflammatory protein profiling was analysed from plasma at the 5-month visit. This study is registered on the ISRCTN Registry, ISRCTN10980107, and recruitment is ongoing.

FINDINGS

2320 participants discharged from hospital between March 7, 2020, and April 18, 2021, were assessed at 5 months after discharge and 807 (32·7%) participants completed both the 5-month and 1-year visits. 279 (35·6%) of these 807 patients were women and 505 (64·4%) were men, with a mean age of 58·7 (SD 12·5) years, and 224 (27·8%) had received invasive mechanical ventilation (WHO class 7-9). The proportion of patients reporting full recovery was unchanged between 5 months (501 [25·5%] of 1965) and 1 year (232 [28·9%] of 804). Factors associated with being less likely to report full recovery at 1 year were female sex (odds ratio 0·68 [95% CI 0·46-0·99]), obesity (0·50 [0·34-0·74]) and invasive mechanical ventilation (0·42 [0·23-0·76]). Cluster analysis (n=1636) corroborated the previously reported four clusters: very severe, severe, moderate with cognitive impairment, and mild, relating to the severity of physical health, mental health, and cognitive impairment at 5 months. We found increased inflammatory mediators of tissue damage and repair in both the very severe and the moderate with cognitive impairment clusters compared with the mild cluster, including IL-6 concentration, which was increased in both comparisons (n=626 participants). We found a substantial deficit in median EQ-5D-5L utility index from before COVID-19 (retrospective assessment; 0·88 [IQR 0·74-1·00]), at 5 months (0·74 [0·64-0·88]) to 1 year (0·75 [0·62-0·88]), with minimal improvements across all outcome measures at 1 year after discharge in the whole cohort and within each of the four clusters.

INTERPRETATION

The sequelae of a hospital admission with COVID-19 were substantial 1 year after discharge across a range of health domains, with the minority in our cohort feeling fully recovered. Patient-perceived health-related quality of life was reduced at 1 year compared with before hospital admission. Systematic inflammation and obesity are potential treatable traits that warrant further investigation in clinical trials.

FUNDING

UK Research and Innovation and National Institute for Health Research.

Convection Oven Determination of Loss of Mass on Drying of Quick Frozen French Fried Potatoes: Collaborative Study

A collaborative study was carried out on one of the methods submitted to the Joint Economic Commission for Europe (ECE)/Codex Alimentarius Commission Group of Experts on the Standardization of Quick Frozen Foods for the determination of moisture in quick frozen french (fried potatoes. The method was based on the determination of loss of mass of the sample on drying in a convection oven 16 h at 103±2°C. Two samples of uncooked quick frozen french fried potatoes and 2 samples of oven quick frozen french fried potatoes were analyzed by 14 and 13 laboratories, respectively. The method is simple and was found to be analytically satisfactory with repeatability and reproducibility values of 0.21 and 2.00 g/100 g french fried potatoes, and 0.29 and 3.00 g/100 g oven french fried potatoes, respectively. The method was adopted by the Group of Experts in preference to other proposed procedures for this determination. The method has been adopted official first action by AOAC.

New prebiotic chemistry inspired filter media for stormwater/greywater disinfection

Greywater and stormwater have received significant attention due to increasing water scarcity. Passive filtration such as biofiltration has been a popular treatment method with its low energy input and environmental friendliness. However, pathogen removal capacity needs improvement to achieve safe water quality. In this study, a prebiotic chemistry inspired copolymer based on aminomalononitrile and 3,4,5-trihydroxybenzaldehyde (AMNT30) was introduced to develop antimicrobial media for passive filtration. The AMNT30 polymer provided an adhesive coating on zeolite substrates following a spontaneous polymerisation process at room temperature. AMNT30 coated media were investigated for metal loading capacity, surface morphology, E. coli removal and metal leaching after filtration of different water sources (i.e. stormwater, greywater, and deionised water) at low/high conductivity. The coating enhanced metal ion loading on the surface and demonstrated that >8 log reduction of E. coli can be achieved for silver loaded materials compared to a 1 log reduction for copper loaded materials. The coating also increased the stability of the metals on the media irrespective of inflow characteristics. This study provided the first example using AMNT30 to create antimicrobial water purification media. It is expected that this technology will find applications in the water treatment industry.

A monomeric red fluorescent protein with low cytotoxicity

Multicolour labelling with fluorescent proteins is frequently used to differentially highlight specific structures in living systems. Labelling with fusion proteins is particularly demanding and is still problematic with the currently available palette of fluorescent proteins that emit in the red range due to unsuitable subcellular localization, protein-induced toxicity and low levels of labelling efficiency. Here we report a new monomeric red fluorescent protein, called FusionRed, which demonstrates both high efficiency in fusions and low toxicity in living cells and tissues.

Generic, symptom based, exercise rehabilitation; integrating patients with COPD and heart failure

BACKGROUND

Patients with Chronic Heart Failure (CHF) develop similar symptoms of exertional breathlessness and fatigue as patients with COPD. Although pulmonary (exercise based) rehabilitation (PR) is an integral part of the management of COPD, the potential for exercise rehabilitation (ER) to assist patients with CHF may not be as readily appreciated. We investigated whether combined ER for patients with CHF and COPD was feasible and effective using the model of PR.

METHODS

57 patients with CHF were randomized 2:1 to 7 weeks ER (CHF-ER) or 7 weeks of usual care (CHF-UC). As a comparator 55 patients with COPD were simultaneously recruited to the same ER program (COPD-ER). The primary outcome measure was the Incremental Shuttle Walk Test (ISWT) and the secondary outcome measures were the Endurance Shuttle Walk Test (ESWT), isometric quadriceps strength and health status.

RESULTS

27 CHF and 44 COPD patients completed ER and 17 patients with CHF completed UC. The CHF-ER group made significant improvements, compared to CHF-UC, in the mean (95%CI) ISWT distance; 62(35-89)m vs -6(-11 to 33)m p < 0.001. The CHF-ER group also made statistically significant improvements in health status. The improvements in exercise performance and health status were similar between patients with CHF and COPD, treated with ER.

CONCLUSION

Patients with CHF who undergo ER improve similarly in their exercise performance and health status to COPD. Combined training programs for COPD and CHF are effective and feasible, such that service provision could be targeted around common disability rather than the primary organ disease.

Chondrosarcoma of larynx: review of literature and clinical experience

Laryngeal chondrosarcomas are rare, cartilaginous tumours, and around 300 cases have been reported in the literature. They are slow-growing tumours which present difficulties both in diagnosis and treatment. Most patients eventually require radical surgery. However, over the last 10 years, we have diagnosed two cases of laryngeal chondrosarcoma and managed them conservatively by endoscopic debulking and regular follow up. The objective of this article is to highlight the conservative approach in managing these patients, particularly in the presence of co-morbid conditions.

Quantitation of fluoride ion released sarin in red blood cell samples by gas chromatography-chemical ionization mass spectrometry using isotope dilution and large-volume injection

A new method for measuring fluoride ion released isopropyl methylphosphonofluoridate (sarin, GB) in the red blood cell fraction was developed that utilizes an autoinjector, a large-volume injector port (LVI), positive ion ammonia chemical ionization detection in the SIM mode, and a deuterated stable isotope internal standard. This method was applied to red blood cell (RBC) and plasma ethyl acetate extracts from spiked human and animal whole blood samples and from whole blood of minipigs, guinea pigs, and rats exposed by whole-body sarin inhalation. Evidence of nerve agent exposure was detected in plasma and red blood cells at low levels of exposure. The linear method range of quantitation was 10-1000 pg on-column with a detection limit of approximately 2-pg on-column. In the course of method development, several conditions were optimized for the LVI, including type of injector insert, injection volume, initial temperature, pressure, and flow rate. RBC fractions had advantages over the plasma with respect to assessing nerve agent exposure using the fluoride ion method especially in samples with low serum butyrylcholinesterase activity.

Performance of a pilot-scale high rate algal pond system treating abattoir wastewater in rural South Australia: nitrification and denitrification

As part of a study examining the efficacy of high-rate algal pond treatment of high-strength abattoir wastewater, the impact of pond configuration and loading rate on nitrification was determined. The extent of nitrification in all ponds was consistent with mass balance estimates of oxygen demand and availability. Deeper ponds were more stable nitrifying systems, with shallow ponds displaying greater variation in response to changes in nitrogen loading. In a separate experiment the pond system was modified by covering a part of an in-series HRAP to exclude light, providing conditions suitable for denitrification. Specific denitrification rates were often within the range typical for endogenous carbon sources, with mass balance calculations indicating removals of up to 95%.

Design-based estimation of surface area in thick tissue sections of arbitrary orientation using virtual cycloids

Surface area is a first-order stereological parameter with important biological applications, particularly at the intersection of biological phases. To deal with the inherent anisotropy of biological surfaces, state-of-the-art design-based methods require tissue rotation around at least one axis prior to sectioning. This paper describes the use of virtual cycloids for surface area estimation of objects and regions in thick, transparent tissue sections cut at any arbitrary (convenient) orientation. Based on the vertical section approach of Baddeley et al., the present approach specifies the vertical axis as the direction of sectioning (i.e. the direction perpendicular to the tissue section), and applies computer-generated cycloids (virtual cycloids) with their minor axis parallel to the vertical axis. The number of surface-cycloid intersections counted on focal planes scanned through the z-axis is proportional to the surface area of interest in the tissue, with no further assumptions about size, shape or orientation. Optimal efficiency at each x-y location can be achieved by three virtual cycloids orientated with their major axes (which are parallel to the observation planes) mutually at an angle of 120 degrees. The major practical advantage of the present approach is that estimates of total surface area (S) and surface density (SV) can be obtained in tissue sections cut at any convenient orientation through the reference space.

Characterisation of oxygen dynamics within a high-rate algal pond system used to treat abattoir wastewater

As part of a study examining the efficacy of high-rate algal pond treatment of high-strength abattoir wastewater, the oxygen dynamics of a pilot scale system were characterised. The relationship between photosynthesis and irradiance was investigated using online data collected throughout a year of operation under varying conditions of climate and wastewater quality. Changes in climate were reflected in changes in the net rate of photosynthesis in deep ponds, consistent with adaptation of algal populations to changing light intensity, whilst the response of shallow ponds was more varied. The use of online monitoring and the calculation in real time of photosynthetic rates should allow for improved design and management of full scale treatment systems and further the understanding of factors driving biological reactions within these systems.

Efficacy of laser palatoplasty: four-year results

There are few reports on the long-term results of laser-assisted uvulopalatoplasty (LAUP), with some casting doubt about its long-term efficacy. We report satisfactory results in patients with more than four years' follow-up. We conducted a retrospective study of patients who underwent LAUP at the Princess of Wales Hospital over a period of five years. Thirty-three patients underwent LAUP as a day case procedure. They had had a mean follow-up period of four years and five months. Twenty-eight of these were asked details of their pre- and postoperative levels of snoring regarding frequency, volume and disturbance to their partners. There was a 50% reduction in frequency of snoring, a 51.85% reduction in volume and a 53.7% reduction in disturbance to their partners. All these figures are statistically significant (p<0.001). Overall, 60.8% of the patients felt the surgery was successful and had reduced their snoring to acceptable levels. We conclude that LAUP is an effective treatment for snoring, even in the long term.

Hand exsanguination: prospective randomised blind study of an established versus a modified technique

One hundred patients undergoing elective hand surgery were randomized to have their hands exsanguinated by either the Rhys-Davies exsanguinator alone or the Rhys-Davies exsanguinator supplemented by a 500 ml bag of intravenous fluid which was placed in the patient's palm as the exsanguinator was rolled up the limb. The quality of the exsanguination was assessed by the surgeon using a pre-defined subjective scoring system. There were no significant differences in the exsanguination scores of the two treatment groups.

Translational regulation of renal proximal tubular epithelial cell transforming growth factor-beta1 generation by insulin

We have previously demonstrated that the proximal tubular cell may contribute to the pathogenesis of renal interstitial fibrosis in diabetes. Transforming growth factor (TGF)-beta1 is one of a group of pro-fibrotic cytokines and growth factors, which have been associated with the development of interstitial fibrosis. The aim of the current study was to examine the effect of insulin on the generation of TGF-beta1 by proximal tubular cells. HK-2 cells were grown to confluence in the absence of insulin, and serum deprived for 48 hours before all experimental manipulations. Addition of insulin (5 microg/ml) to the culture medium led to a time-dependent increase in TGF-beta1 concentration in the cell culture supernatant, and increased incorporation of radiolabeled amino acids into TGF-beta1 suggestive of de novo TGF-beta1 protein synthesis. Addition of insulin did not alter TGF-beta1 mRNA expression as assessed by reverse transcriptase-polymerase chain reaction or Northern analysis. Insulin-induced increase in TGF-beta1 concentration was not abrogated by actinomycin D, however, stimulation by insulin, in the presence of cycloheximide led to a dose-dependent decrease in TGF-beta1 production. Addition of insulin had no effect on TGF-beta1 mRNA stability as assessed by actinomycin D chase, but led to increased binding of a cytoplasmic protein to a putative stem loop structure in the 5'-UTR of TGF-beta1 mRNA, previously implicated in the posttranscriptional control of TGF-beta1 synthesis. To address the functional significance of insulin-induced alteration in TGF-beta1 synthesis, we examined its effect on matrix turnover. Insulin stimulated type IV collagen gene expression and an increase in the concentrations of the type IV collagen laid down in the extracellular matrix. This increase in type IV collagen was abrogated when cells were stimulated by insulin in the presence of an anti-TGF-beta1-blocking antibody. In conclusion the data demonstrate that insulin may directly alter the production of TGF-beta1 by renal proximal tubular cells by a posttranscriptional mechanism, and that this may have implications for the increase in extracellular matrix that accompanies diabetic nephropathy.

Early feeding strategies in preterm and critically ill neonates

This two-part article presents feeding strategies for the NICU population over the first several weeks of life. It focuses primarily on the theory and approach to feeding extremely low birth weight (ELBW) infants, but also addresses some issues pertinent to larger, ill infants. The premise for these recommendations is that avoiding early malnutrition in ELBW and ill infants has both short- and long-term benefits. Many practitioners may consider our approach to be somewhat aggressive. In this strategy, total parenteral nutrition (TPN) is initiated in the first hours after birth and is given together with initially small, and then increasing, enteral feedings beginning on the first or second day of life. The role of the TPN is to provide rapid, maximal nutrition and that of the early enteral feedings is to "prime" the gut and stimulate normal gastrointestinal tract activity.

Pott's puffy tumour: an unusual presentation and management

Pott's puffy tumour is a rare clinical entity in this era of antibiotics. It is usually seen as a complication of frontal sinusitis. This is the first report of Pott's puffy tumour presenting as a complication of maxillary sinusitis. This is also the first reported case of Pott's puffy tumour treated with debridement and gentamicin beads. We discuss the clinical presentation and successful treatment of this rare disease.

Efficacy and safety of 'hot' tonsillectomy

Recurrent acute tonsillitis, peritonsillar infections and quinsy (peritonsillar abscess) are common clinical conditions that present to a general practitioner. Management in general practice and in hospital is confounded by apparently conflicting treatment options in the medical literature. We have developed clear guidelines as part of an ongoing audit cycle which include performing quinsy or 'hot' tonsillectomy in selected cases, alongside conservative treatments to ensure the speedy recovery and minimal hospitalisation of all patients, with resultant cost benefits.

Rhys-Davies exsanguinator: pressure characteristics and technique for improving performance

This paper reports the results of an investigation into the pressure exerted by the Rhys-Davies exsanguinator on the palm and dorsum of the hand. We hypothesised that, due to the shape of the hand, the palm is shielded from the full effect of the exsanguinator, but our study showed that it is compressed as well as the dorsum. However, placing a bag of fluid in the patient's palm significantly increased the pressure applied to the palm.

A mannose selection system for production of fertile transgenic maize plants from protoplasts

 Maize (Zea mays L.) callus cultures cannot use mannose as a sole carbohydrate source, but can utilize fructose for that purpose. Phosphomannose isomerase (PMI) can convert mannose to fructose. Transgenic maize plants were obtained by selecting polyethylene glycol (PEG)-mediated transformed protoplasts on mannose (20 g/l) containing medium. Transgenic calluses and plants carrying the PMI structural gene, manA, were able to convert mannose to fructose. The PEG-mediated protoplast transformation frequency was 0.06%. Stable transformation was confirmed by PCR, PMI activity, germination tests, and by histochemical staining with 5-bromo-4-chloro-3-indolyl-β-D-glucuronide (X-Gluc). Stable integration of the transgenes into the maize genome was demonstrated in T₁ and T₂ plants. Results indicate that the mannose selection system can be used for maize PEG-mediated protoplast transformation.

Human Daxx regulates Fas-induced apoptosis from nuclear PML oncogenic domains (PODs)

Daxx was first identified as a protein that binds the cytosolic domain of Fas and links this receptor to an apoptosis pathway involving activation of Jun N-terminal kinase (JNK). We show here that cells overexpressing the human homolog of Daxx (hDaxx) display enhanced sensitivity to apoptosis induced by Fas but not by several other cell death stimuli. hDaxx-mediated enhancement of Fas-induced apoptosis was correlated with accelerated activation of caspases but not with JNK induction. Although specifically enhancing Fas function, hDaxx does not bind Fas and instead is found in the nucleus where it localizes to PML oncogenic domains (PODs). Moreover, the hDaxx protein also exhibits the ability to repress transcription. Mutagenesis studies demonstrated a correlation between the localization of hDaxx to PODs and its ability to enhance Fas-induced cell death. Arsenic trioxide (As(2)O(3)), an agent that accentuates POD formation, collaborated synergistically with overexpression of hDaxx to increase cellular sensitivity to Fas-induced apoptosis. Taken together, these findings argue that hDaxx promotes sensitivity to Fas from a nuclear location, probably by modulating the transcription of genes involved in Fas-induced caspase activation and apoptosis.

Cost and benefit of hospital, hospital- in- the- home and ambulatory care nutrition support services

The instigation of nutrition support, either via the enteral or parenteral route, in individuals unable to maintain adequate nutrition via oral means is based on the premise that such an intervention will reduce both morbidity and mortality and improve quality of life. While there is evidence that active nutrition support improves biochemical and physiological parameters, health professionals are being called upon to demonstrate the cost, benefits and outcomes of nutrition support in the face of budget constraints and increasing demands on health care. Cost savings have been made in hospital nutrition support through increased use of enteral rather than parenteral nutrition support, particularly in Intensive Care Units, and careful use of resources when planning enteral nutrition support. Nutrition support of critically ill and malnourished individuals can reduce morbidity and length of stay. Benefits of home nutrition support programs include avoidance of hospital bed costs and improved lifestyle and psychological well-being. Our experience and that of the literature will be reviewed.

Cellular activation through the ligation of intercellular adhesion molecule-1

In addition to its role in mediating leukocyte adherence to and migration across the endothelium, intercellular adhesion molecule (ICAM)-1 on the surface of interstitial cells has been implicated as a principal adhesion molecule controlling leukocyte infiltration at inflammatory sites. The present study demonstrates that leukocyte binding to fibroblasts isolated from both the human renal cortex and lung and to endothelial cells induced the de novo synthesis of ICAM-1 mRNA and protein through the ICAM-1-dependent activation of the cultured cells. This was mimicked by specifically cross-linking the ICAM-1 receptor with anti-ICAM-1 antibodies. Following cross-linking there was a two- to threefold increase in the steady state levels of ICAM-1 mRNA isolated from the cells. The expression of this mRNA peaked at 1–3 hours and was dose-dependent on the concentration of secondary cross-linking antibody. Peak protein expression was between 18 and 48 hours after cross-linking. Additional data demonstrated a similar increase in the expression of VCAM-1 following ICAM-1 cross-linking. In contrast, there was no reponse as a result of incubation with an isotype-matched control antibody. Both the binding of leukocytes and the cross-linking of ICAM-1 triggered a rise in cytosolic free calcium as the result, in part, of a calcium influx from the extracellular medium. Using BAPTA-AM to chelate intracellular calcium ions indicated that this increase in cytosolic free calcium was directly involved in the initiation of adhesion molecule upregulation. The present study demonstrates that both endothelial cells and fibroblasts can be stimulated by the direct cell surface interaction of ICAM-1 with its ligands on inflammatory cells. One phenotypic change resulting from this interaction is the upregulated synthesis and expression of more cellular adhesion molecules. This may have profound implications for the control and persistence of a leukocyte infiltrate and the progression of inflammatory disease.

Human neutrophils do not degrade major basement membrane components during chemotactic migration

At sites of inflammation, circulating neutrophils (PMNs) migrate through microvessel walls into the subendothelial interstitium. While endothelial passage is mediated by adhesion proteins, including those of the integrin, selectin and immunoglobulin superfamily classes, the mechanisms used to cross the subendothelial basement membrane (BM) are unclear. Studies examining tumour cell invasion and lymphocyte extravasation suggest several possible mechanisms, including proteolysis. Different cells, however, may use different mechanisms to effect passage. To examine neutrophil-basement membrane interactions in more detail, human PMNs were embedded within reconstituted BM (Matrigel) and used in migration assays. The integrity of the gel following migration was assessed by assaying for the release of incorporated radiolabelled products and by-immunoblotting for specific matrix molecule epitopes. PMNs migrated through Matrigel in response to the chemotactic peptide FMLP. Degradation products of laminin, heparan sulphate proteoglycan or of gelatin, however, were not detected. In contrast, phorbol ester, which triggers activation without migration, released approximately 40% of incorporated HSPG, 30% of gelatin and 20% of laminin as intact molecules or degraded fragments. Electron microscopy of migrating cells demonstrated pseudopodia associated with channels within the Matrigel. Although the serine proteinase inhibitor DFP, plasma and a specific anti-neutrophil elastase IgG blocked degradation, these agents failed to inhibit migration. Migration was inhibited, however, when the Matrigel concentration was increased to 10 mg/ml. Thus, although PMNs will degrade matrix components they do not do so during migration, and proteolytic remodelling of the BM is not a pre-requisite for neutrophil passage.

Retroperitoneal collections--aetiology and radiological implications

PURPOSE

Retroperitoneal collections related to the psoas, in the absence of pancreatitis, are uncommon. This study reviews the imaging, pathogenesis and management of retroperitoneal collections with particular emphasis on distinguishing imaging features and the role of percutaneous drainage.

MATERIALS AND METHODS

Twenty-three retroperitoneal collections in 22 patients were reviewed in a 2-year period. Twenty-one patients underwent computed tomography (CT), with ultrasound (US) conducted in 14 and magnetic resonance imaging (MRI) in four. The clinical history and associated aetiological factors were noted. Methods of drainage were compared, pathological/microbiological results were recorded and the clinical outcome noted.

RESULTS

The mean age of presentation was 46.9 years (range 18-85 years). There was a male to female preponderance (17 to 6). Eighteen collections proved to be abscesses with five haematomas confirmed. Of the abscesses, three were primary and 15 were secondary to spinal, gastrointestinal or renal disease. Escherichia coli was the commonest isolated organism followed by Mycobacterium tuberculosis. No haematomas were drained. Twelve abscesses were drained successfully by percutaneous methods; three were managed with antibiotics alone; three were managed surgically.

CONCLUSION

Secondary abscesses predominate and investigation should be directed at excluding a gastrointestinal or renal source. Tuberculous disease remains a significant problem. Percutaneous drainage allows effective management, even in the presence of a secondary abscess.

Carbon isotopic fractionation associated with lipid biosynthesis by a cyanobacterium: relevance for interpretation of biomarker records

For the cyanobacterium Synechocystis UTEX 2470, grown photoautotrophically to a logarithmic stage of growth, the total lipid extract is depleted in 13C by 4.8% relative to average biomass. Depletions observed for acetogenic (straight-chain) lipids range from 7.6 (hexadecanoic acid) to 9.9% (a C16 n-alkyl chain bound in a polar-lipid fraction), with a mass-weighted average of 9.1%. Polyisoprenoid lipids fall into two isotopic groups, with phytol, diplopterol, and diploptene depleted by 6.4-6.9% and bishomohopanol (produced from the extracts by the preparative degradation of bacteriohopanepolyol) depleted by 8.4%. Analysis of the pattern of depletions indicates that two carbon positions in each C5 biomonomer leading to polyisoprenoid products are probably depleted in 13C relative to average biomass. The depletion of bacteriohopanepolyol relative to other polyisoprenoids can be ascribed to changes that occur over the life of each cell: (1) the 13C content of carbon flowing to lipid biosynthesis decreases as the cell size increases and (2) a greater proportion of the bacteriohopanepolyol which, unlike other polyisoprenoids, is present mainly in the cytoplasm rather than in membranes and is synthesized when cells are larger. Chlorophyll a is depleted relative to average biomass by O.7%. Given the observed depletion of 13C in phytol, the heteroaromatic, chlorophyllide portion of chlorophyll must be enriched in 13C by 2.7%. This enrichment is large relative to that in chlorophyllides produced by eukaryotes and may be related to a parallel enrichment of 13C in cyanobacterial glutamic acid. As in many previous investigations of cyanobacterial lipids, long-chain n-alkanes (C22-C29) are found in the extracts. They are, however, enriched in 13C relative to biomass and have isotopic compositions suggesting that they are contaminants of petrochemical origin. Available results indicate that cyanobacterial lipids will be depleted relative to dissolved CO2 that has served as a carbon source by 22-30% and that a wider range of depletions will be characteristic of eukaryotic products. The absence of long-chain n-alkanes in cyanobacteria reduces the possibility that petroleum ever formed from pre-eukaryotic sedimentary debris.

Flexor tenosynovectomy and tenolysis in longstanding rheumatoid arthritis

A total of 43 patients (49 hands; 424 flexor tendons), who had rheumatoid arthritis of more than 15 years duration at the time of surgery, were clinically assessed at a mean follow-up of 5.7 years (range, 1.2-12 years). Pain and inability to flex actively despite a good passive range of motion were the main surgical indications. The results suggest that the patients had excellent sustained pain relief (mean score = 0.9) and were highly satisfied with the outcome of the procedure (mean score = 2.2). 81% had adequate pulp-to-pulp and key pinch. Range of finger motion (total active motion, TAM) was excellent to good in 45% and fair in 22%. Thirty-three per cent were graded as poor and these were found to be multifactorial in origin, with associated significant joint disease, preoperative tendon ruptures, extensive digital surgery, readhesions and combinations of operative procedures which adversely affect the rehabilitation programme. Flexor tenosynovectomy with tenolysis is a useful procedure with a low rate of recurrence.

The tumor burden of locally recurrent breast cancer is a neglected prognostic factor

BACKGROUND

Local recurrence following breast-sparing surgery for breast cancer is no longer considered to be an ominous sign. Why this should be the case is not understood, and it poses a dilemma for the surgical oncologist. When does local recurrence represent an independent threat to survival?

DATA SOURCES

I reviewed the few studies that have considered the size or tumor burden of locally persistent breast cancer, and the results of the Guy's Hospital Trials.

CONCLUSIONS

Locally persistent breast cancer is seldom a risk to patient survival. The surgical literature is seriously deficient in its consideration of the tumor volume of locally persistent cancer. All available evidence suggests that a recurrent tumor is a risk only if its volume exceeds that of the original tumor. Patients appear to have a stable level of host defense against metastasizing tumor cells. Those who survive one breast cancer without developing distant disease can be expected to survive the local persistence of a similar volume of tumor. Investigators should compare the size of each persistent lesion to the size of the patient's primary cancer. Excess deaths will occur only among patients whose persistent disease exceeds the volume of the primary.