A simple assessment of the effect of strontium on the urinary excretion of calcium in Sprague Dawley rats

This study was aimed at investigating the impact of varying concentrations of strontium (Sr) on calcium (Ca) excretion via the urine and determine its impact on kidney stone formation. Twenty adult male Sprague Dawley rats weighing between 200 and 300 g were selected. The rats were randomly divided into four groups of five. One group was used as a control group while the other three groups were experimental. The diet of the rats was modulated over a 12 week period to investigate the impact of Sr on the urinary excretion of Ca. Urinary samples were collected every 2 weeks from the rats. The rats were fed water ad libitum. After the study the rats were euthanised and their kidneys harvested. Urine and kidney samples from the rats were analysed using Total Reflection X-Ray Fluorescence (TXRF). In the urine excretion of Ca increased with increased intake of Sr in the diet. Sr excretion via the urine also increased with increased dietary intake. There was a correlation of 0.835 at the significance level of 0.01 between Ca and Sr in the urine. However, for the kidneys, the varying concentration of Sr did not impact the retention of Ca in the kidneys. There was increased retention of Sr in the kidneys with increased dietary intake. In this study an increase of Sr in the diet resulted in an increase in urinary excretion of Ca.

Surgical relevance of anatomic variations of the right hepatic vein

BACKGROUND

Variations in the anatomy of hepatic veins are of interest to transplant surgeons, interventional radiologists, and other medical practitioners who treat liver diseases. The drainage patterns of the right hepatic veins (RHVs) are particularly relevant to transplantation services.

AIM

The aim was to identify variations of the patterns of venous drainage from the right side of the liver. To the best of our knowledge, there have been no reports on RHV variations in in a Caribbean population.

METHODS

Two radiologists independently reviewed 230 contrast-enhanced computed tomography scans performed in 1 year at a hepatobiliary referral center. Venous outflow patterns were observed and RHV variants were described as: (1) Tributaries of the RHV; (2) Variations at the hepatocaval junction (HCJ); and (3) Accessory RHVs.

RESULTS

A total of 118 scans met the inclusion criteria. Only 39% of the scans found conventional anatomy of the main hepatic veins. Accessory RHVs were present 49.2% and included a well-defined inferior RHV draining segment VI (45%) and a middle RHV (4%). At the HCJ, 83 of the 118 (70.3%) had a superior RHV that received no tributaries within 1 cm of the junction (Nakamura and Tsuzuki type I). In 35 individuals (29.7%) there was a short superior RHV with at least one variant tributary. According to the Nakamura and Tsuzuki classification, there were 24 type II variants (20.3%), six type III variants (5.1%) and, five type IV variants (4.2%).

CONCLUSION

There was significant variation in RHV patterns in this population, each with important relevance to liver surgery. Interventional radiologists and hepatobiliary surgeons practicing in the Caribbean must be cognizant of these differences in order to minimize morbidity during invasive procedures.

Anatomic variations of the intra-hepatic biliary tree in the Caribbean: A systematic review

BACKGROUND

In the classic descriptions of the human liver, the common hepatic duct forms at the confluence of left and right hepatic ducts. Many authors have documented variations in the intra-hepatic ductal system, but to the best of our knowledge there has been no report on bile duct variations in Caribbean populations.

AIM

To evaluate the variations in bile duct anatomy using magnetic resonance cholangiography (MRC) in unselected patients at a major hepatobiliary referral centre in the Eastern Caribbean. Knowledge of the intra-hepatic biliary anatomy is important to optimize service delivery for any physician treating liver and biliary disorders.

METHODS

This study was carried out at a tertiary referral hospital for hepatobiliary diseases in the Eastern Caribbean. We retrospectively evaluated magnetic resonance cholangiograms in 152 consecutive patients at this facility over a two-year period from April 1, 2017 to March 31, 2019. Two consultant radiologists experienced in MRC interpretation reviewed all scans and described biliary anatomy according to the Huang’s classification. A systematic review of published studies was performed and relevant data were extracted in order to calculate the global prevalence of each biliary variant. The variants in our population were compared to the global population.

RESULTS

There were 152 MRCs evaluated in this study in 86 males and 66 females. There were 109 (71.7%) persons with “classic” biliary anatomy (type A1) and variants were present in 43 (28.3%) persons. There was no statistical relationship between the presence of anatomic variants and gender or ethnicity. We encountered the following variants: 29 (19.1%) type A2, 7 (4.6%) type A3, 6 (3.95%) type A4, 0 type A5 and a single variant (quadrification) that did not fit the classification system. Compared to the global prevalence, our population had a significantly greater occurrence of A1 anatomy (71.7% vs 62.6%; P = 0.0227) and A2 trifurcations (19.1% vs 11.5%; P = 0.0069), but a significantly lower incidence of A3 variants (4.61% vs 11.5%; P = 0.0047).

CONCLUSION

There are significant differences in intra-hepatic biliary anatomy in this unselected Eastern Caribbean population compared to global statistics. Specifically, persons of Caribbean descent have a greater incidence of Huang A2 trifurcations and a lower incidence of Huang A3 variants.

Clinically Oriented Classification of Anatomic Variants of the Umbilical Fissure for Ligamentum Teres in the Human Liver

Background In the classic descriptions of the human liver, the umbilical fissure (UF) is a long, narrow groove on the visceral surface that receives the ligamentum teres hepatis. In this study, we document the UF variations encountered in a series of cadaveric dissections. Methods We reported UF variations using the following classification: Type I refers to "normal" anatomy where there is a long, narrow groove. In type II, the UF was covered by a fibrotic band devoid of hepatic parenchyma. In type III variants, an extension of hepatic parenchyma partially covered but did not obliterate the UF. In type IV variants, the hepatic parenchyma formed a bridge over the UF, completely obliterating the groove. After institutional review board approval, we observed all consecutive cadaveric dissections over five years and recorded the characteristics and dimensions of each UF and its immediate relations. Results There were 69 cadavers, and variant UFs were present in 38 (55.1%) cadavers: type II (1.5%), type III (20.3%), and type IV (33.3%). Conclusions In this Jamaican population, only 44.9% of persons had conventional "normal" anatomy and 55.1% had UF variants. These variants are clinically significant, as they lead to misinterpretation of patient imaging and can hinder operative procedures on the liver.

Human liver umbilical fissure variants: pons hepatis (ligamentum teres tunnel)

PURPOSE

In the classical description of normal liver anatomy, the umbilical fissure is a long, narrow groove that receives the ligamentum teres hepatis. The pons hepatis is an anatomic variant, where the umbilical fissure is converted into a tunnel by an overlying bridge of liver parenchyma. We carried out a study to evaluate the existing variations of the umbilical fissure in a Caribbean population.

METHODS

We observed all consecutive autopsies performed at a facility in Jamaica and selected cadavers with a pons hepatis for detailed study. A pons hepatis was considered present when the umbilical fissure was covered by hepatic parenchyma. We recognized two variants: an open-type (incomplete) pons hepatis in which the umbilical fissure was incompletely covered by parenchyma ≤ 2 cm in length and a closed type (complete) pons hepatis in which the umbilical fissure was covered by a parenchymal bridge > 2 cm and thus converted into a tunnel. We measured the length (distance from transverse fissure to anterior margin of the parenchymatous bridge), width (extension across the umbilical fissure in a coronal plane) and thickness (distance from the visceral surface to the hepatic surface measured at the mid-point of the parenchymal bridge in a sagittal plane) of each pons hepatis. A systematic literature review was also performed to retrieve data from relevant studies. The raw data from these retrieved studies was used to calculate the global point prevalence of pons hepatis and compared the prevalence in our population.

RESULTS

Of 66 autopsies observed, a pons hepatis was present in 27 (40.9%) cadavers. There were 15 complete variants, with a mean length of 34.66 mm, mean width of 16.98 mm and mean thickness of 10.98 mm. There were 12 incomplete variants, with a mean length of 17.02 mm, width of 17.03 mm and thickness of 9.56 mm. The global point prevalence of the pons hepatis (190/5515) was calculated to be or 3.45% of the global population.

CONCLUSIONS

We have proposed a classification of the pons hepatis that is reproducible and clinically relevant. This allowed us to identify a high prevalence of pons hepatis (41%) in this Afro-Caribbean population that is significantly greater than the global prevalence (3.45%; P < 0.0001).

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.

Hepatic surface grooves in Trinidad and Tobago

PURPOSE

Hepatic surface grooves (HSGs) are prominent depressions on the antero-superior surface of the liver. We sought to document the prevalence of HSGs in an Eastern Caribbean population.

METHODS

We observed all consecutive autopsies performed at a facility in Trinidad and Tobago and recorded the presence, number, location, width, length and depth of any HSG identified. Each liver was then sectioned to document intra-parenchymal abnormalities.

RESULTS

Sixty Autopsies were observed. There were HSGs in 9 (15%) cadavers (5 females and 4 males), at an average age of 66 years (range 48-83, Median 64, SD ± 10.4). The HSGs were located on the diaphragmatic surface of the right hemi-liver in 8 (89%) cadavers, left medial section in 4 (44%), left lateral section in 3 (33%) and coursing along Cantlie's plane in 3 (33%) cadavers. Eight (89%) cadavers with HSGs had other associated anomalies: accessory inferior grooves (5), parenchymal nutmeg changes (5), abnormal caudate morphology (4), hyperplastic left hemi-liver (3), lingular process (2), bi-lobar gallbladder (1) and/or abnormal ligamentous attachments (1).

CONCLUSIONS

Approximately 15% of unselected Afro-Caribbean persons in this Eastern Caribbean population have HSGs. Every attempt should be made to identify HSGs on pre-operative imaging because they can alert the hepatobiliary surgeon to: (1) associated anatomic anomalies in 89% of cases, (2) associated hepatic congestion in 56% of persons, (3) increased risk of bleeding during liver resections and (4) increased technical complexity of liver resections. The association between HSGs, cardiovascular complications, hepatic congestion and nutmeg liver prompted us to propose a new aetiologic mechanism for HSG formation, involving localized hyperplasia at growth zones due to upregulation of beta-catenin levels.

Inferior Hepatic Fissures: Anatomic Variants in Trinidad and Tobago

Classic descriptions of the visceral surface of the human liver only define three fissures: transverse, sagittal and umbilical fissures. Any additional fissures that are present on the visceral surface of the liver are considered variant inferior hepatic fissures (IHFs). This study was carried out to document the prevalence of IHFs in the Eastern Caribbean. Knowledge of these variants is important to clinicians who treat liver disorders in persons of the Caribbean diaspora. In this study, two independent researchers observed all consecutive autopsies performed at the facility over a period of 10 weeks. They examined the visceral surface of the unfixed liver in situ. Any specimen with variant IHFs was selected for detailed study. We documented the relation of the variant IHFs to nearby viscera and then explanted the livers using a standardized technique. The following details were recorded for each liver: number, location, depth, length, and width of IHFs. All measurements were checked independently by two researchers and the average measurement was used as the final dimension. Each liver was then sectioned in 1 cm sagittal slices to document the relationship of intraparenchymal structures. We observed 60 consecutive autopsies in unselected cadavers. Variant IHFs were present in 21 (35%) cadavers at a mean age of 68.25 years (range: 61 - 83; median 64.5; standard deviation (SD) ± 8.45). The variants included a deep fissure in the coronal plane between segments V and VI in 19 (31.7%) cadavers (related to the right branch of the portal vein in 63.2% of cases), a well-defined segment VI fissure running in a sagittal plane in four (6.7%) cadavers, a well-defined fissure incompletely separating the caudate process from the caudate lobe proper in five (8.3%) cadavers, a consistent fissure that arose from the left side of the transverse fissure and coursed between segments II and III in three (5%) cadavers, and a deep coronal fissure dividing the quadrate to form an accessory quadrate lobe in one (1.7%) cadaver. Almost one in three unselected persons in this population have anatomically variant fissures on the visceral surface of the liver. The variants include Rouvière's sulci (31.7%), caudate notches (8.3%), segment VI fissures (6.7%), left medial segment fissures (5%), and quadrate fissures (1.7%). The clinical relevance of these variants is discussed. Any clinician treating liver diseases in persons of Caribbean extract should be aware of their presence.

The liver and Chilaiditi's syndrome: Significance of hepatic surface grooves

Chilaiditi's syndrome describes a symptomatic patient with radiographic findings of interposed colon between the diaphragm and right lobe of liver. It may mimic a pneumoperitoneum on plain radiographs. We present a case in which Chilaiditis' syndrome was entertained, delaying a decision for laparotomy. This case reinforces the diagnostic difficulty associated with Chilaiditi's syndrome, and it increases awareness of an uncommon variation in the liver surface anatomy.

Accessory Inferior Sulci of the Liver in an Afro-Caribbean Population

INTRODUCTION

There have been no previous reports on the anatomic variations that exist on inferior surface of the liver in Caribbean populations. This information is important to optimize radiology and hepatobiliary surgical services in the region.

METHODS

Two investigators independently observed 69 cadaveric dissections over five years and described the variations in surface anatomy.

RESULTS

In this population 88% of cadaveric livers had conventional hepatic surface anatomy. However, 12% had accessory sulci present on the visceral surface of the liver, with a 7:1 male preponderance. When present, there was 100% correlation between the presence of Rouvière's sulcus and the right branch of portal pedicle.

CONCLUSION

Abnormal surface anatomy is present in 12% of unselected specimens in this Caribbean population. Interventional radiologists and hepatobiliary surgeons practicing in the Caribbean must be cognizant of these differences in order to minimize morbidity during invasive procedures.

Hepatic surface grooves in an Afro-Caribbean population: a cadaver study

INTRODUCTION

There have been no previous reports on hepatic surface grooves in an Afro-Caribbean population. This information is important to optimize radiology and hepatobiliary surgical services in the region.

METHODS

Two investigators independently observed 69 cadaveric dissections performed over five years at the University of the West Indies. Variations in surface anatomy were described.

RESULTS

In this Caribbean population the majority of patients had conventional hepatic surface anatomy (88%). However, we found a greater incidence of hepatic surface grooves (12%) than reported in international literature.

CONCLUSION

Abnormal surface anatomy is present in 12% persons in this population. Interventional radiologists and hepatobiliary surgeons practicing in the Caribbean must be cognizant of these differences in order to minimize morbidity during invasive procedures.

Accessory renal arteries in a Caribbean population: a computed tomography based study

INTRODUCTION

The commonest variation to the classic anatomic description of renal arterial supply is the presence of accessory renal arteries. The incidence varies widely according to ethnicity. There is no data on the prevalence of these anomalies in persons of Caribbean ethnicity.

METHODS

All CT scans done over two years from July 1, 2010 to June 30, 2012 were retrospectively evaluated. The anatomy of the renal arterial supply was reported from these studies and the anatomy of accessory renal arteries was documented.

RESULTS

There were 302 CT scans evaluated and accessory renal arteries were present in 109/302 (36.1%) CT scans, 95% confidence interval 30.6%, 41.4%. There were 71/309 (23.5%) patients with accessory arteries on the left and 54/309 (17.9%) had them on the right (p 0.087). Of these, 16 (14.7%) patients had bilateral accessory renal arteries present. The most common origin for the accessory arteries was the abdominal aorta in 108 (99.1%) cases and in 1 case the accessory artery arose from the coeliac trunk. There were 80 left sided accessory renal arteries: 17 (21.3%) upper polar and 27 (33.8%) lower polar arteries. Of 62 right sided accessory arteries, 14 (22.6%) were upper polar and 26 (42%) were lower polar arteries.

CONCLUSION

This is the first population-based report of anatomic anomalies in renal arterial supply in a Caribbean population. These are important findings that may affect vascular and urologic procedures on persons of Caribbean ethnicity.

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.