Venous drainage of the left liver: an evaluation of anatomical variants and their clinical relevance.

AIM: To evaluate the variations in venous drainage from the left liver. MATERIALS AND METHODS: A retrospective evaluation was performed of all consecutive abdominal computed tomography (CT) examinations at a tertiary referral facility between 1 January and 30 June 2018. Osirix (Pixmeo SARL, Bernex, Switzerland) was used to examine the major hepatic veins and their tributaries in each scan. The classification of variants as proposed by Nakamura and Tsuzuki was used to describe the findings. The following information was collected: ramification pattern, number, length and diameter of middle (MHV) and left (LHV) hepatic vein tributaries. Two researchers collected data independently, and the average measurements were used as the final dimensions. RESULTS: Of 102 examinations evaluated, only 27 demonstrated the conventional venous drainage patterns. The LHV and MHV combined to form a common trunk that emptied into the inferior vena cava (IVC) in 75 (73.5%) cases. The common trunk had a mean length of 8.89 mm and mean diameter of 20.18 mm. Other patterns included Nakamura and Tsuzuki type I (27.5%), type II (29.4%) and type III variants (16.7%). In addition, 4.9% of patients had absent superior middle veins and 80% had supernumerary short hepatic veins (4%). CONCLUSION: Only 26.5% of patients in this population had conventional venous drainage from the left liver. Surgeons and radiologists in hepatobiliary practice should be aware of these variants in order to minimise morbidity when performing invasive procedures.

Beta Cell Regenerating Potential of Azadirachta indica (Neem) Extract in Diabetic Rats.

OBJECTIVE: This study evaluated the ability of 0.8% neem leaf extract (NLE) to treat diabetes mellitus by assessing its effects on blood glucose, insulin levels and islet morphology in streptozotocin (STZ)-induced diabetic Sprague-Dawley rats. METHODS: Diabetes was induced in two to three-day old rat pups by STZ intraperitoneally (60 mg/kg), followed by a further 40 mg/kg dose 12-23 weeks later. The diabetic treated (DT) rats received 0.8% w/v NLE in tap water while diabetic control (DC) and normal control (NC) rats received water ad libitum. Body weight, water and chow consumption, and blood glucose were evaluated weekly. Blood and pancreas were collected at the end of the study to evaluate serum insulin and islet histology, respectively. RESULTS: Neem leaf extract (0.8%) improved weight gain and beta cell regeneration but did not reduce blood glucose. Serum insulin increased slightly in the treated group and three-fold in the DC group (p < 0.05). CONCLUSION: The results suggest that NLE has beta cell regenerating potential.

Variants of hepatic arterial supply in a Caribbean population: a computed tomography based study.

AIM: To evaluate the spectrum of hepatic arterial variants in unselected patients undergoing computed tomography (CT) of the abdomen at the main regional referral centre in the northern Anglophone Caribbean. MATERIALS AND METHODS: Two radiologists independently reviewed 309 CT angiographic studies performed over 2 years between 1 July 2010 and 30 June 2012 at a regional hepatobiliary referral centre for the Northern Caribbean. The anatomical variations were described according to a conventional classification proposed by Michels et al. RESULTS: In this Caribbean population, the majority of patients had conventional Michels' type 1 vascular anatomy (63.4%). However, a statistically significantly greater incidence of Michels' type 2 variations (20.4%) were found than that reported in the international literature and a lower incidence of type 3 (5.2%), type 6 (0.6%), and type 9 (0) patterns than previously reported. One case with variations not previously described in this classification was also encountered. CONCLUSION: Although 63.4% of persons in a Caribbean population have conventional vascular anatomy, the distribution of anatomical variants is quite different to that seen in North American and European centres. Interventional radiologists and hepatobiliary surgeons practicing in the Caribbean must be cognizant of these differences in order to minimize morbidity and mortality during invasive procedures.

Low-frequency fourier transform infrared spectroscopy of the oxygen-evolving complex in Photosystem II.

In this communication, we report our progress on the development of low-frequency Fourier transform infrared (FTIR) spectroscopic techniques to study metal-substrate and metal-ligand vibrational modes in the Photosystem II/oxygen-evolving complex (PS II/OEC). This information will provide important structural and mechanistic insight into the OEC. Strong water absorption in the low-frequency region (below 1000 cm(-1)), a lack of suitable materials, and temperature control problems have limited previous FTIR spectroscopic studies of the OEC to higher frequencies (>1000 cm(-1)). We have overcome these technical difficulties that have blocked access to the low-frequency region and have developed successive instruments that allow us to move deeper into the low-frequency region (down to 350 cm(-1)), while increasing both data accumulation efficiency and S/N ratio. We have detected several low-frequency modes in the S(2)/S(1)spectrum that are specifically associated with these two states. Our results demonstrate the utility of FTIR techniques in accessing low-frequency modes in Photosystem II and in proteins generally.

Low-frequency fourier transform infrared spectroscopy of the oxygen-evolving and quinone acceptor complexes in photosystem II.

The low-frequency (<1000 cm-1) region of the IR spectrum has the potential to provide detailed structural and mechanistic insight into the photosystem II/oxygen evolving complex (PSII/OEC). A cluster of four manganese ions forms the core of the OEC and diagnostic manganese-ligand and manganese-substrate modes are expected to occur in the 200-900 cm-1 range. However, water also absorbs IR strongly in this region, which has limited previous Fourier transform infrared (FTIR) spectroscopic studies of the OEC to higher frequencies (>1000 cm-1). We have overcome the technical obstacles that have blocked FTIR access to low-frequency substrate, cofactor, and protein vibrational modes by using partially dehydrated samples, appropriate window materials, a wide-range MCT detector, a novel band-pass filter, and a closely regulated temperature control system. With this design, we studied PSII/OEC samples that were prepared by brief illumination of O2 evolving and Tris-washed preparations at 200 K or by a single saturating laser flash applied to O2 evolving and inhibited samples at 250 K. These protocols allowed us to isolate low-frequency modes that are specific to the QA-/QA and S2/S1 states. The high-frequency FTIR spectra recorded for these samples and parallel EPR experiments confirmed the states accessed by the trapping procedures we used. In the S2/S1 spectrum, we detect positive bands at 631 and 602 cm-1 and negative bands at 850, 679, 664, and 650 cm-1 that are specifically associated with these two S states. The possible origins of these IR bands are discussed. For the low-frequency QA-/QA difference spectrum, several modes can be assigned to ring stretching and bending modes from the neutral and anion radical states of the quinone acceptor. These results provide insight into the PSII/OEC and demonstrate the utility of FTIR techniques in accessing low-frequency modes in proteins.

Drugs and the blood-brain barrier

This monograph seeks to provide overall information on the role of the blood-brain barrier particularly in relation to entry of various drugs into the Central Nervous System.

Drugs and the blood-brain barrier

This monograph seeks to provide overall information on the role of the blood-brain barrier particularly in relation to entry of various drugs into the Central Nervous System. (AU)