Exploring the influence of metal cations on individual hydrogen bonds in Watson-Crick guanine-cytosine DNA base pair: An interacting quantum atoms analysis.

This study delves into the nature of individual hydrogen bonds and the relationship between metal cations and hydrogen bonding in the Watson-Crick guanine-cytosine (GC) base pair and its alkali and alkaline earth cation-containing complexes (Mn+-GC). The findings reveal how metal cations affect the nature and strength of individual hydrogen bonds. The study employs interacting quantum atoms (IQA) analysis to comprehensively understand three individual hydrogen bonds within the GC base pair and its cationic derivatives. These analyses unveil the nature and strength of hydrogen bonds and serve as a valuable reference for exploring the impact of cations (and other factors) on each hydrogen bond. All the H ⋯ $$ \cdots $$ D interactions (H is hydrogen and D is oxygen or nitrogen) in the GC base pair are primarily electrostatic in nature, with the charge transfer component playing a substantial role. Introducing a metal cation perturbs all H ⋯ $$ \cdots $$ D interatomic interactions in the system, weakening the nearest hydrogen bond to the cation (indicated by a) and reinforcing the other (b and c) interactions. Notably, the interaction a, the strongest H ⋯ $$ \cdots $$ D interaction in the GC base pair, becomes the weakest in the Mn+-GC complexes. A broader perspective on the stability of GC and Mn+-GC complexes is provided through interacting quantum fragments (IQF) analysis. This approach considers all pairwise interactions between fragments and intra-fragment components, offering a complete view of the factors that stabilize and destabilize GC and Mn+-GC complexes. The IQF analysis underscores the importance of electron sharing, with the dominant contribution arising from the inter-fragment exchange-correlation term, in shaping and sustaining GC and Mn+-GC complexes. From this point of view, alkaline and alkaline earth cations have distinct effects, with alkaline cations generally weakening inter-fragment interactions and alkaline earth cations strengthening them. In addition, IQA and IQF calculations demonstrate that the hydration of cations led to small changes in the hydrogen bonding network. Finally, the IQA interatomic energies associated with the hydrogen bonds and also inter-fragment interaction energies provide robust indicators for characterizing hydrogen bonds and complex stability, showing a strong correlation with total interaction energies.

Completion of hand-written surgical consent forms is frequently suboptimal and could be improved by using electronically generated, procedure-specific forms.

INTRODUCTION: Completion of hand-written consent forms for surgical procedures may suffer from missing or inaccurate information, poor legibility and high variability. We audited the completion of hand-written consent forms and trialled a web-based application to generate modifiable, procedure-specific consent forms. METHODS: The investigation comprised two phases at separate UK hospitals. In phase one, the completion of individual responses in hand-written consent forms for a variety of procedures were prospectively audited. Responses were categorised into three domains (patient details, procedure details and patient sign-off) that were considered "failed" if a contained element was not correct and legible. Phase two was confined to a breast surgical unit where hand-written consent forms were assessed as for phase one and interrogated for missing complications by two independent experts. An electronic consent platform was introduced and electronically-produced consent forms assessed. RESULTS: In phase one, 99 hand-written consent forms were assessed and the domain failure rates were: patient details 10%; procedure details 30%; and patient sign-off 27%. Laparoscopic cholecystectomy was the most common procedure (7/99) but there was significant variability in the documentation of complications: 12 in total, a median of 6 and a range of 2-9. In phase two, 44% (27/61) of hand-written forms were missing essential complications. There were no domain failures amongst 29 electronically-produced consent forms and no variability in the documentation of potential complications. CONCLUSION: Completion of hand-written consent forms suffers from wide variation and is frequently suboptimal. Electronically-produced, procedure-specific consent forms can improve the quality and consistency of consent documentation.

Ileal MALT lymphoma causing massive gastrointestinal haemorrhage revealed on computed tomography angiography.

Primary MALT lymphomas affecting the ileum are rare, and their presentation with massive haemorrhage exceptional. This report describes such a case. The patient presented with melaena and haemodynamic instability, but normal upper gastrointestinal endoscopy. Subsequent imaging with multi-detector row computed tomography angiography both localised the bleeding source to the ileum and identified the underlying tumour, resulting in considerably earlier introduction of appropriate management. The patient made an excellent recovery and remains in remission.

The incremental value of dual modality PET/CT imaging over PET imaging alone in advanced colorectal cancer.

BACKGROUND: (18)Fluoro-2-Deoxy Glucose (18 FDG) positron emission tomography (PET) impacts upon the management of recurrent colorectal cancer (CRC) but is limited by anatomical localisation. The development of integrated positron emission and computerised tomography (PET/CT) yields high anatomical resolution combined with the PET data. We evaluate the added value of PET/CT over PET alone. METHOD: Thirty-one consecutive patients had PET/CT for suspected recurrent CRC. Two blinded observers (A and B) reported images from PET alone and from integrated PET/CT. Lesion detection, lesion localisation, diagnostic certainty and impact on surgical management was assessed for each data set and then compared. The minimum clinical follow up was for 8 months (median 9.6 months) and 7 patients had histological confirmation of diagnosis. RESULTS: Compared to PET alone, PET/CT the percentage of lesions accurately localised increased from 96% to 99% for observer A and 86% to 99% for Observer B. PET/CT increased the number of lesions reported as definitely abnormal or normal from 78% to 95% for Observer A and from 72% to 94% for Observer B. Surgical management was changed in 6 patients (19%). Inter-observer variability was reduced with PET/CT. CONCLUSION: PET/CT improves the accuracy of reporting in recurrent colorectal cancer and influences surgical management in a significant proportion of patients when compared to PET only imaging.

Laparoscopic resection of diverticular fistulae: a 10-year experience.

OBJECTIVE: Until recently the laparoscopic approach was reserved for uncomplicated diverticular disease. We show that fistulating diverticular disease can be resected safely, with good clinical outcome via a laparoscopic approach. METHOD: Between April 1994 and May 2005, 31 consecutive patients [17 male, median age of 63 years (range 40-85)], underwent attempted laparoscopic resection for diverticular fistulae. Patient data were prospectively recorded. RESULTS: There were 22 colovesical and nine colovaginal fistulae. The median operative time was 150 min (range 60-310) and the median postoperative stay was 7 days (range 3-21). Conversion to an open procedure was required in nine of 31 patients (29%). This rate fell to 10% in cases performed after April 2000. There were two nonsurgically related postoperative deaths. Both occurred in the converted group. At 3 months follow-up, two patients complained of frequency of stools, which settled by 6 months. To date there has been no recurrence of symptomatic diverticulosis or fistulation. CONCLUSION: Totally laparoscopic resection for diverticular fistulae is safe and feasible. Fistulae should not be considered as a contraindication to laparoscopic resection for an experienced laparoscopic surgeon.

The absent kidney in 99Tcm-MAG3 renogram: a dramatic reversible consequence of contrast nephrotoxicity superimposed on renal obstruction.

99Tcm-mercaptoacetyltriglycine (MAG3) renogram is a robust imaging technique used to delineate upper urinary tract obstruction. The changes observed on the renogram are often reversible on relief of obstruction. We present two cases illustrating the extreme consequence of contrast nephrotoxicity on pre-existing obstructed kidneys. In one case, this led to severe impairment of perfusion and uptake observed on 99Tcm-MAG3 renogram and in the second case virtual non-visualization of the obstructed kidney. Subsequent treatment of obstruction, led to dramatic improvement in renal function. It is important for clinicians, nuclear medicine physicians and radiologists to be aware of the potential of contrast nephrotoxicity in obstructed kidneys.