Population-based cohort study of variation in the use of emergency cholecystectomy for benign gallbladder diseases

Background

The aims of this prospective population-based cohort study were to identify the patient and hospital characteristics associated with emergency cholecystectomy, and the influences of these in determining variations between hospitals.

Methods

Data were collected for consecutive patients undergoing cholecystectomy in acute UK and Irish hospitals between 1 March and 1 May 2014. Potential explanatory variables influencing the performance of emergency cholecystectomy were analysed by means of multilevel, multivariable logistic regression modelling using a two-level hierarchical structure with patients (level 1) nested within hospitals (level 2).

Results

Data were collected on 4744 cholecystectomies from 165 hospitals. Increasing age, lower ASA fitness grade, biliary colic, the need for further imaging (magnetic retrograde cholangiopancreatography), endoscopic interventions (endoscopic retrograde cholangiopancreatography) and admission to a non-biliary centre significantly reduced the likelihood of an emergency cholecystectomy being performed. The multilevel model was used to calculate the probability of receiving an emergency cholecystectomy for a woman aged 40 years or over with an ASA grade of I or II and a BMI of at least 25·0 kg/m2, who presented with acute cholecystitis with an ultrasound scan showing a thick-walled gallbladder and a normal common bile duct. The mean predicted probability of receiving an emergency cholecystectomy was 0·52 (95 per cent c.i. 0·45 to 0·57). The predicted probabilities ranged from 0·02 to 0·95 across the 165 hospitals, demonstrating significant variation between hospitals.

Conclusion

Patients with similar characteristics presenting to different hospitals with acute gallbladder pathology do not receive comparable care.

Liver metastases from breast cancer: Surgical resection or not? A case-matched control study in highly selected patients

AIM

To determine whether, in a highly selected patient population, medical treatment combined with surgical resection of liver metastases from breast cancer is associated with improved survival compared with medical treatment alone.

PATIENTS AND METHODS

Between 1988 and 2007, 100 liver resections for metastatic breast cancer were performed at Institut Curie, 51 of which met the criteria for inclusion in this case-control study. With the exception of bone metastases, patients with other distant metastasis sites were excluded. Surgery was only performed in patients with stable disease or disease responding to medical treatment evaluated by imaging evaluation. Surgical cases were individually matched with 51 patients receiving medical treatment only. All patients had 4 or fewer resectable liver metastases. The study group was matched with the control group for age, year of breast cancer diagnosis, time to metastasis, TNM stage, hormone receptor status and breast cancer tumour pathology.

RESULTS

Univariate analysis confirmed a survival advantage for patients lacking bone metastases and axillary lymphadenopathy at the time of breast cancer diagnosis and for surgically treated patients. Multivariate analysis indicated that surgery and the absence of bone metastases were associated with a better prognosis. A multivariate Cox model adapted for paired data showed a RR = 3.04 (CI: 1.87-4.92) (p < 0.0001) in favour of surgical treatment.

CONCLUSION

Surgical resection of liver metastases from primary breast cancer appears to provide a survival benefit for highly selected patients.

Pilot study of the effects of local pressure on microvascular function in the diabetic foot

AIM

The aim of the study was to determine whether areas of the diabetic foot that experience high pressures during normal activity also demonstrate reductions in cutaneous microvascular flow and/or endothelial function.

METHODS

Sixteen patients with diabetes mellitus and eight healthy, age-matched control subjects were recruited. Maps of dynamic pressure on the plantar aspect of both feet were recorded during a normal gait cycle, and the skin microvascular blood flow response to the endothelium-dependent vasodilator acetylcholine was assessed at the sites of highest and lowest plantar pressure over the metatarsal heads.

RESULTS

Patients with diabetes had higher plantar pressures than control subjects (P = 0.002), but there were no significant differences in basal skin blood flow or acetylcholine response between the groups. In the patients, baseline flow was increased (P = 0.041) but the acetylcholine response reduced (P = 0.03) at the high-pressure compared with the low-pressure site; this was most apparent in those who were particularly at risk of ulceration due to high plantar pressures.

CONCLUSIONS

Chronically raised plantar pressure in the diabetic foot is associated with increased basal skin blood flow, compared with lower pressure areas on the same foot. Further work is required to determine whether, and under what conditions, this additional hyperaemia is protective or maladaptive. In addition, high-pressure areas have a reduced responsiveness to an endothelium-dependent vasodilator, although the clinical significance of these changes is not clear.

Growth factors in the treatment of diabetic foot ulcers

BACKGROUND

Chronic foot ulceration is a major source of morbidity in diabetic patients. Despite traditional comprehensive wound management, including vascular reconstruction, there remains a cohort of patients with non-responding wounds, often resulting in amputation. These wounds may benefit from molecular manipulation of growth factors to enhance the microcirculation.

METHODS

A review of the current literature was performed using Pubmed, with secondary references obtained from key articles.

RESULTS AND CONCLUSION

There has been a generally disappointing clinical outcome from growth factor trials, although topical platelet-derived growth factor has shown significant benefit and should be considered in non-healing, well perfused ulcers after failure of conventional wound care. The modulatory role of the extracellular matrix in the cellular response to growth factors and data from regenerative-type fetal wound healing are further areas of interest. The chemical induction of microvessel formation may become a future therapeutic option.

Tongue protrusion strength and fatiguability: relationship to apnoea/hypopnoea index and age

The sleep apnoea/hypopnoea syndrome (SAHS) is characterized by retroglossal or retropalatal narrowing. The site of obstruction, and the fact that negative pressure in the upper airway increases retroglossal airway size, suggests that tongue muscles may play a role in the maintenance of upper airway patency. We therefore hypothesized that tongue protrusion strength and fatiguability may be predictors of apnoea/hypopnoea index, vary with age and may be different in SAHS patients and normal subjects. Maximal strength (Fmax) and fatiguability (measured as the total time subjects were able to maintain 50% Fmax on three consecutive occasions separated by 30 s) were assessed using a force transducer in 98 consecutive apnoeic/hypopnoeic male patients referred to our laboratory for sleep studies [apnoea/hypopnoea index (AHI) range 3-130/h, age range 30-74 y]. Fmax and fatiguability were also compared in 15 male SAHS patients (mean AHI 20/h) and 15 nonsnoring male subjects matched for age, body mass index and fat free mass. A further 26 SAHS patients had tongue protrusion strength/fatiguability measured before, during and after a night's sleep. Log AHI was only weakly correlated with Fmax (r=- 0.21; P=0.03) and age (r=0.23; P=0.025), but not to fatiguability (P > 0.05). Comparison between SAHS and nonsnoring subjects did not demonstrate significant differences in Fmax (P=0.1) or fatiguability (P=0.1). There was no evidence of a change in muscle strength (P > 0.05) or fatigue (P > 0.05) during the course of a night's sleep. We conclude that tongue protrusion strength and fatiguability are unlikely to be important factors in the pathogenesis of SAHS.

Purification and characterization of multiple forms of the pineapple-stem-derived cysteine proteinases ananain and comosain

A mixture of ananain (EC 3.4.22.31) and comosain purified from crude pineapple stem extract was found to contain numerous closely related enzyme forms. Chromatographic separation of the major enzyme forms was achieved after treatment of the mixture with thiol-modifying reagents: reversible modification with 2-hydroxyethyl disulphide provided enzyme for kinetic studies, and irreversible alkylation with bromotrifluoroacetone or iodoacetamide gave enzyme for structural analyses by 19F-n.m.r. and electrospray mass spectrometry respectively. Structural and kinetic analyses revealed comosain to be closely related to stem bromelain (EC 3.4.22.32), whereas ananain differed markedly from both comosain and stem bromelain. Nevertheless, differences were seen between comosain and stem bromelain in amino acid composition and kinetic specificity towards the epoxide inhibitor E-64. Differences between five isolatable alternative forms of ananain were characterized by amidolytic activity, thiol stoichiometry and accurate mass determinations. Three of the enzyme forms displayed ananain-like amidolytic activity, whereas the other two forms were inactive. Thiol-stoichiometry determinations revealed that the active enzyme forms contained one free thiol, whereas the inactive forms lacked the reactive thiol required for enzyme activity. M.s. provided direct evidence for oxidation of the active-site thiol to the corresponding sulphinic acid.

Investigation of sequence homology in a group of type-II restriction/modification isoschizomers

We have dissected the cloned PstI M and R genes to make DNA hybridization probes spanning most of the sequence. These subclones, and also the intact sequence, were used to search for nucleic acid homology by Southern blot in the DNA from twelve organisms which produce PstI isoschizomers. One of these probes, a 206-bp fragment from the N-terminal domain of the endonuclease, showed significant hybridisation in four strains (Escherichia coli strains RFL48, RFL49 and RFL83, and Streptomyces albus P). No significant hybridisation was detected with other parts of the PstI sequences. We have used computer similarity searches to look for homology between the PstI proteins and the known sequences of other type-II systems that recognise different sites. We postulate a possible recognition domain within the M.PstI methyltransferase based on similarity to the M.PaeR7 and M.TaqI methyltransferases.

Heterogeneity of insulin action in muscle: influence of blood flow

The influence of blood flow (BF) and basal neuromotor tone on in vivo insulin-stimulated glucose uptake (Rg') in muscle was examined using the euglycemic clamp plus deoxyglucose/glucose tracer (insulin action) and labeled microsphere (BF) techniques. Anesthesia was used to produce perturbations in BF and/or activity compared with conscious rats. An index of muscle glycolytic flux (Gf) was estimated from Rg' in excess of glycogen synthesis. Gf and glycogen synthesis were significantly increased in soleus and red gastrocnemius (RG) during insulin infusion (150 mU/l) in conscious rats. Rg' was related to muscle BF in conscious rats (r = 0.92). In anesthetized rats, Rg' and BF were reduced in soleus, RG, red quadriceps, and plantaris (e.g., soleus 69%, P less than 0.001, and 80%, P less than 0.001, respectively). However, it is unlikely that Rg' and BF are causally related because fractional extraction of glucose by muscle was low (approximately 9%); fractional extraction increased during anesthesia (17%, P less than 0.01); BF but not Rg' was reduced by anesthesia in extensor digitorum longus, white gastrocnemius, and white quadriceps; and reduced Rg' during anesthesia in soleus and RG was mainly due to reduced GF. In conclusion, BF is not a major contributor to the heterogeneity in insulin-stimulated glucose uptake among individual muscles under basal conditions. These data suggest that neuromotor tone may indirectly influence the magnitude of muscle glucose uptake during insulin elevation via a substrate switching effect. This may give rise to a significant increase in glycolytic flux of glucose in those muscles that exhibit elevated activity even at rest (e.g., soleus).(ABSTRACT TRUNCATED AT 250 WORDS)

In vivo insulin sensitivity in the rat determined by euglycemic clamp

Our aim was to develop the glucose clamp (GC) technique in the conscious rat for assessment of in vivo insulin sensitivity. A 2-h euglycemic GC could be performed in chronically cannulated rats using 625 microliter blood. Overnight-fasted rats were infused with porcine insulin (1.67 mU . kg-1 . h-1). Insulin levels of 41 +/- 2 (SE) mU/liter were produced in rats aged 91 +/- 4 days with a 60- to 120-min glucose infusion rate (GIR60-120) of 10.6 +/- 0.6 mg . kg-1 . min-1 (n = 9) during euglycemia. GIR60-120 was significantly (P less than 0.025) reduced in rats aged greater than 130 days (mean, 169 +/- 16 days) to 7.7 +/- 1.2 mg . kg-1 . min-1 (n = 7). Metabolic clearance rate of porcine insulin (46 +/- 3 ml . kg-1 . min-1) and GIR60-120 compared with plateau plasma insulin levels are higher than values reported in humans. The latter may be due to suppression of a higher basal hepatic glucose production or increased potency of porcine compared with native insulin. We conclude that the GC can be accomplished in the rat. When combined with tracer administration and subsequent killing, it should provide a quantitative in vivo measurement of insulin sensitivity in individual tissues.

Rapid pulsatile corticosterone secretion in the rat is not confirmed

We attempted to confirm and extend a previous suggestion by other workers that, in the rat, corticosterone may be released as a series of very short pulses with a period of one minute. We measured the corticosterone concentration in the blood of chronically cannulated, unanaesthetised male rats, repeatedly, at ten second intervals, for periods of up to 25 minutes while the rats were engaged in normal activity or sleep or were subject to acute or chronic stress. We could find no evidence of the proposed rapid pulsatile secretion and suggest that the earlier finding may have been artifactual.