A novel 3D volumetric method for directly quantifying porosity and pore space morphology in flocculated suspended sediments.

Flocculated suspended sediments (flocs) are found in a variety of environments globally, and their transport and behavior bear substantial importance to several industries including fisheries, aquaculture, and shipping. Additionally, the modelling of their behavior is important for estuarine and coastal flood prediction and defence, and the process of flocculation occurs in other unrelated industries such as paper and chemical production. Floc porosity is conventionally assessed using inferential indirect or proxy data approaches. These methods underestimate floc porosity % by c. 30% and cannot measure the micro-scale complexity of these pore spaces and networks, rendering inputs to models sub-optimal. This study introduces a novel 3D porosity and pore space quantification protocol, that produces directly quantified porosity % and pore space data.•3D floc data from micro-CT scanning is segmented volumetrically•This segmented volume is quantified to extract porosity and several pore space parameters from the floc structure.

Quantification of 3-dimensional structure and properties of flocculated natural suspended sediment.

Natural sediment flocs are fragile and highly heterogeneous aggregates of biogenic and minerogenic material typically with high porosity and low density. In aquatic environments dominated by fine, cohesive or mixed sediments they can dominate suspended sediment flux. Consequently, monitoring and modelling the behaviour, transport and distribution of flocs is very important for many aquatic industries, maintenance of waterways and conservation and management of aquatic waterbodies. Mathematical models that predict the behaviour of flocs rely on the accurate assessments of the size, shape, density, porosity and fractal dimension of flocs. These inherently 3-dimensional (3D) characteristics are typically derived from 2-dimensional (2D) data, largely due to the challenges associated with sampling, capturing, imaging and quantifying these fragile aggregates. We have developed new volumetric microscopy techniques which can quantify 3D internal and external structures and characteristics of sediment flocs. Here, these techniques were applied to quantify the 3D size (volume), shape and fractal dimension of natural and artificial sediment flocs and compare them to standard 2D approaches. Our study demonstrates that 2D approaches are under-estimating shape complexity and over-estimating the size and mass settling flux of flocs by up to two orders of magnitude, and the discrepancy between 2D and 3D is most marked for natural, organic rich macroflocs. Our study has significant implications for estimations of sediment flux at local to global scales within in aquatic environments. These new data and approaches offer the potential to improve the current parameterisation of sediment transport models and to improve the accuracy of current field-monitoring techniques.

Three psychological treatments for bulimia nervosa. A comparative trial.

The specificity and magnitude of the effects of cognitive behavior therapy in the treatment of bulimia nervosa were evaluated. Seventy-five patients who met strict diagnostic criteria were treated with either cognitive behavior therapy, a simplified behavioral version of this treatment, or interpersonal psychotherapy. Assessment was by interview and self-report questionnaire, and many aspects of functioning were evaluated. All three treatments resulted in an improvement in the measures of the psychopathology. Cognitive behavior therapy was more effective than interpersonal psychotherapy in modifying the disturbed attitudes to shape and weight, extreme attempts to diet, and self-induced vomiting. Cognitive behavior therapy was more effective than behavior therapy in modifying the disturbed attitudes to shape and weight and extreme dieting, but it was equivalent in other respects. The findings suggest that cognitive behavior therapy, when applied to patients with bulimia nervosa, operates through mechanisms specific to this treatment and is more effective than both interpersonal psychotherapy and a simplified behavioral version of cognitive behavior therapy.

Lipid lowering therapy leads to a reduction in sodium-lithium countertransport activity.

Erythrocyte sodium-lithium countertransport (SLC) was measured in 17 patients with either combined hyperlipidaemia or hypercholesterolaemia before and after lipid lowering therapy. Before treatment SLC related to the serum triglyceride level and was increased in combined hyperlipidaemia. After treatment the SLC had returned to normal and the change in SLC was related to the change in serum triglyceride levels. Raised SLC is associated with essential hypertension but is not related to blood pressure. Therefore, the association of raised SLC with hyperlipidaemia and essential hypertension appears to have different underlying mechanisms.

Altered membrane microviscosity in essential hypertension: relationship with family history of hypertension and sodium-lithium countertransport activity.

OBJECTIVE: To investigate the alterations in erythrocyte ghost membrane microviscosity in essential hypertensive patients and to determine the relationship between these changes and the sodium-lithium countertransport activity as a sensitive marker of membrane function. SUBJECTS: Forty-three normolipidaemic essential hypertensive patients (23 treated, 20 untreated) and 27 normotensive controls were studied. Patients were attending the hospital hypertension clinic or a local general practitioner's surgery. METHODS: Erythrocyte sodium-lithium countertransport activity was measured. The Michaelis constant (Km) for extracellular sodium and maximal reaction velocity for sodium-lithium countertransport were measured in a subgroup consisting of 22 essential hypertensive patients and 11 normotensive controls. Erythrocyte membrane microviscosity was measured using fluorescence polarization anisotropy of 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1-[4-trimethylammoniumphenyl]-6-phenyl-1,3,5-hexatriene (TMA-DPH). RESULTS: There was no significant difference in the fluorescence polarization anisotropy of DPH or TMA-DPH between normotensive and essential hypertensive patients. However, the fluorescence polarization anisotropy of TMA-DPH was increased significantly (reflecting increased membrane microviscosity) in hypertensive patients with a family history of hypertension compared with in patients without a family history of hypertension. The standard sodium-lithium countertransport activity was elevated in essential hypertensive patients compared with normotensive controls, and the Km for sodium was significantly lower in patients with a family history of hypertension than in patients without a family history of hypertension. Patients with a family history of hypertension were clustered, with significantly lower Km for sodium and higher TMA-DPH anisotropies than either hypertensive patients without a family history of hypertension or normotensive controls. CONCLUSIONS: These findings suggest that a high membrane microviscosity affecting the outer region of the lipid bilayer is associated with altered sodium-lithium countertransport kinetics in a subgroup of essential hypertensive patients consisting of those with a family history of hypertension.

Elevated sodium-lithium countertransport: a familial marker of hyperlipidaemia and hypertension?

Erythrocyte sodium-lithium countertransport was measured in normolipidaemic and hyperlipidaemic hypertensive patients, hyperlipidaemic normotensive patients and normal controls. Hypertension and hyperlipidaemia were each independently associated with raised sodium-lithium countertransport (by analysis of variance, P less than 0.01 and P less than 0.01). The effects were additive so that hyperlipidaemia could not explain raised sodium-lithium countertransport in hypertension. In hyperlipidaemic hypertensive patients, levels of plasma cholesterol, triglycerides, low-density lipoprotein (LDL) cholesterol and very-low-density lipoprotein (VLDL) cholesterol were increased, and high-density lipoprotein (HDL) cholesterol was reduced. Of these patients, 73.3% had a known family history of hypertension. Their normotensive first degree relatives were studied, and 48% of these also had raised sodium-lithium countertransport and abnormal plasma lipids (raised cholesterol, triglycerides and LDL cholesterol, and reduced HDL cholesterol). Relatives with normal sodium-lithium countertransport had normal lipids. Therefore, raised sodium-lithium countertransport was associated with the inheritance of both hypertension and hyperlipidaemia, and this could explain why raised sodium-lithium countertransport has been associated with a family history of both hypertension and associated cardiovascular disease.

Effects of induced elated and depressed mood on self-focused attention.

Recent accounts of depression propose a central role for increased self-focus in the onset and maintenance of depression. The present study investigated whether there might also be a converse effect of depressed mood increasing self-focus. A state measure of self-focused attention was administered to normal subjects before and after induction of depressed or happy mood. Compared to happy subjects, depressed subjects showed more negative and less positive self-focus. Positive and negative external focus were unaffected by mood. A reciprocally reinforcing relationship between depressed mood and negative self-focus may be important in onset and maintenance of depression.

A middle ear teratoma causing acute airway obstruction.

A rare benign teratoma of the middle ear, eustachian tube and nasopharynx presenting in an 8-month-old infant, is reported. The true nature of the tumour was not appreciated until after partial surgical resection from the middle ear. This procedure was complicated 3 days later by life-threatening airway obstruction, caused by the tumour slipping from the eustachian tube and obstructing the larynx. This unusual presentation and the pathology of the teratoma are discussed. The case demonstrates the importance of nasopharyngeal examination where middle ear lesions distort the eustachian tube.

Pulmonary rehabilitation after acute exacerbation of chronic obstructive pulmonary disease in patients who previously completed a pulmonary rehabilitation program.

PURPOSE: Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) impair health-related quality of life (HRQL). We evaluated the effect of an abbreviated repeat pulmonary rehabilitation (PR) program on HRQL after an AECOPD. METHODS: Patients who had completed PR were followed for up to 12 months to identify an AECOPD and then placed in randomized groups to receive a 3-week repeat-PR intervention or usual care. Measures of HRQL (Chronic Respiratory Disease Questionnaire, CRQ) and functional exercise capacity (6-minute walk distance, 6MWD) were collected at 2 (T(1)), 5 (T(2)), and 12 weeks (T(3)) post-AECOPD. The repeat-PR program was undertaken between T(1) and T(2). Between-group differences were examined using repeated- measures analysis of variance or covariance. RESULTS: Of the 60 patients (30 men, age 69+/-8 years, forced expiratory volume in 1 second 0.86+/-0.40 L, 6MWD 367+/-99 m) followed, 41 experienced an AECOPD 14 +/- 11 weeks after completion of the initial PR program and 33 completed the study. Of these, 16 and 17 were randomized to the intervention and control groups, respectively. No between-group differences were demonstrated at T(2) or T(3). With the exclusion of 5 subjects who experienced a second AECOPD between T(1) and T(3), the participants in the intervention group demonstrated greater reduction in dyspnea when compared to those in the control group at T(3) (0.8+/-1.6 vs -0.4+/-1.3 points per item, P = .04). CONCLUSIONS: The reduction in dyspnea in those who did not experience a second AECOPD provides preliminary evidence for the role of repeat programs. The application of repeat PR should be refined in larger trials.

Assessing clinical competency in medical senior house officers: how and why should we do it?

Most consultants are involved in the training and assessment of several grades of doctors in training especially senior house officers (SHOs) and specialist registrars. In the medical and other specialties there is an increasing trend towards assessing junior doctors' competency using the record of in-training assessment process for specialist registrars and using the Royal College of Physicians folder to record competences of medical SHOs. It is necessary to consider why there is a need to assess competency, how it may be done practically, and the advantages and disadvantages of this system of assessment. There are considerable hurdles to the implementation of this system in the medical specialties within today's NHS and the organisation may need to undergo fairly radical change to facilitate this system.

Management of peptic oesophageal stricture.

Peptic oesophageal stricture develops in approximately 10-15% of patients with inadequately treated reflux oesophagitis and poses a difficult clinical problem. The management of reflux oesophagitis has been revolutionised by improvements in medical management, endoscopic and balloon techniques of oesophageal dilatation. The major advance has been the development of inhibitors of gastric acid secretion: histamine receptor antagonists and H(+) + K(+) + ATPase inhibitors. Studies have recently shown that the H(+) + K(+) + ATPase inhibitor omeprazole is effective in the management of severe resistant reflux disease with peptic stricture formation, leading to a reduction in the number of oesophageal dilatations required by up to 60% of patients. The aim of this article is to review the current medical, endoscopic and surgical management of severe peptide oesophagitis with stricture formation.

Bilateral oronasal fistulas secondary to an infected maxillary subperiosteal implant. Report of a case.

The literature pertaining to maxillary subperiosteal implants is relatively sparse. There are even fewer reports of complications following this implant technique. The following article describes the surgical management of bilateral oronasal fistulas that developed secondary to chronic infection following the placement of a maxillary subperiosteal implant.

Erythrocyte sodium-lithium countertransport in primary and renal hypertension: relation to family history.

Sodium-lithium countertransport (Na-Li CT) has been reported to be increased in essential hypertension (EHT) but the nature and degree of distinction from normal controls in unclear. Of 44 unselected patients with EHT in the hospital hypertension clinic 36% had Na-Li CT greater than the normal control range and 70% of these had a family history of hypertension. Almost all the patients with normal Na-Li CT had no family history of hypertension. Analysis of variance showed that raised Na-Li CT was related to both a family history of hypertension and a family history of a cardiovascular event. Of 23 patients with hypertension secondary to renal disease, 43% had Na-Li CT greater than the normal control range and raised Na-Li CT was related to both a family history of hypertension and a family history of cardiovascular event in the same way as EHT. Raised Na-Li CT was not characteristic of EHT but identified a subgroup of patients with EHT and a family history of hypertension, some of whom also had renal disease.

Mother-infant attachment: the importance of the mother's visual field.

The purpose of this study was to answer 2 questions: (1) how important to 2-year-old children is fact-to-face contact with the mother, and (2) do attachment behaviors, such as looking at, talking to, and being close to mothers, interact in a compensatory fashion? 24 male and female children, 18 to 30 months, were observed with their mothers for 15 minutes in 3 conditions: (1) mother facing tethered toys, (2) mother facing away from toys, and (3) mother behind a partition and not visible from toys. Observations were made by time-lapse photography techniques. Results indicated that the potential for face-to-face contact was important: children spent 94% of their time in mother's visual field when she faced the toys and 50% of their time in her visual field when she either faced away or was behind the partition. Overall, they established face-to-face contact about 12% of the time. Some compensation was observed: talking and physical proximity increased as visual contact decreased.

Red cell Na+/Li+ countertransport and Na+/H+ exchanger isoforms in human proximal tubules.

BACKGROUND: Increased activity of the Na+/Li+ countertransporter (SLC) is a well-recognized intermediate phenotype of hypertension and diabetic nephropathy and may indicate a predisposition to hypertension. Previous work has attempted to link this membrane transport marker to altered Na+ reabsorption in the proximal tubule. Since the Na+/H+ exchanger (NHE) isoforms 1 and 3 are expressed in the basolateral and apical membranes of the proximal tubule, respectively, we investigated the relationship between these transport proteins and red cell SLC to examine whether the peripheral blood transport phenotype is associated with altered levels of transport proteins in the proximal tubule. METHODS: Proximal tubules were prepared from human nephrectomy specimens. NHE-1 and NHE-3 were detected on Western blots by specific antibodies. Red cell SLC was also measured. RESULTS: Both NHE-1 and NHE-3 proteins were demonstrated, with molecular weights of 97 and 85 kD, respectively. SLC was very strongly correlated with the level of NHE-3 protein (r = 0.78, P < 0.001) and was negatively related to NHE-1 protein (r = -0.32). In multiple regression analysis, only NHE-3 and NHE-1 protein levels were significant predictors of red cell SLC, accounting for up to about 70% of the variance of this parameter. CONCLUSIONS: We conclude that red cell SLC may be a marker of increased NHE-3 protein expression in the proximal tubule, which may account for the blunted pressure natriuresis and predisposition to hypertension.

Kinetics of sodium-lithium countertransport activity in patients with uncomplicated type 1 diabetes.

1. Increased erythrocyte sodium-lithium countertransport activity has been reported to be associated with nephropathy in type 1 diabetes and linked to a family history of essential hypertension. 2. This study aimed to determine the mechanism of increased sodium-lithium countertransport activity. Sodium-lithium countertransport kinetics were measured in uncomplicated and hyperlipidaemic type 1 diabetic patients. 3. In the nine out of 31 uncomplicated type 1 diabetic patients who had high sodium-lithium countertransport activity, the sodium affinity (Km) was normal but the maximum velocity (Vmax) was increased. 4. Hyperlipidaemia, when present in diabetic patients, was associated with increased sodium-lithium countertransport activity, but could not explain the high activity in uncomplicated type 1 diabetic patients in whom plasma lipid concentrations were normal. 5. Sodium-lithium countertransport activity is increased in type 1 diabetes by a mechanism different to that in essential hypertension, where the mechanism is a low Km (increased sodium affinity). Hence familial hypertension cannot explain the raised sodium-lithium countertransport activity in type 1 diabetes.

Changes in erythrocyte sodium-lithium countertransport kinetics in diabetic nephropathy.

1. It has been proposed that raised erythrocyte sodium-lithium countertransport activity in type 1 diabetic patients is associated with an increased risk of developing diabetic nephropathy. Diabetic patients with established nephropathy would therefore be expected to have high activity. 2. Standard sodium-lithium countertransport activity, sodium affinity (Km) and maximum velocity (Vmax) were measured in type 1 diabetic patients at different stages of diabetic nephropathy and in appropriately matched uncomplicated diabetic patients and normal control subjects. 3. A small proportion (15%) of patients with nephropathy had standard sodium-lithium countertransport activity higher than the control range. However, mean standard sodium-lithium countertransport activity in the diabetic patients with nephropathy [mean +/- SEM, 0.26 +/- 0.12 mmol of Li+ h-1 (l of cells)-1] was not significantly higher than in the uncomplicated diabetic patients [0.27 +/- 0.03 mmol of Li+ h-1 (l of cells)-1] or in the normal control subjects [0.25 +/- 0.02 mmol of Li+ h-1 (l of cells)-1]. 4. There were marked changes in the kinetic characteristics of the sodium-lithium countertransport in the diabetic patients with nephropathy so that there were decreases in both Km and Vmax. 5. These kinetic changes could not be attributed to an effect of either renal failure per se or the duration of diabetes. 6. The characteristic kinetic changes in sodium-lithium countertransport may indicate underlying alterations in membrane function with the onset of nephropathy in type 1 diabetes.

Raised affinity for extracellular sodium of the sodium-lithium countertransporter is associated with a family history of hypertension and uraemia in patients with renal disease.

1. Increased affinity for sodium (Km) at an external site of the sodium-lithium countertransporter and altered membrane microviscosity in the surface regions of the lipid bilayer identifies a group of essential hypertensive patients with a genetic predisposition to hypertension. The present study investigated the kinetic properties of the sodium-lithium countertransporter and membrane microviscosity in patients with hypertension, renal disease and impaired renal function. 2. Sixty patients with renal disease (28 chronic renal failure, 30 hypertensive, 23 family history of hypertension) were investigated. Standard erythrocyte sodium-lithium countertransport activity, sodium affinity constant (Km), maximum reaction velocity (Vmax) and membrane microviscosity were measured. 3. Patients with renal disease and a family history of hypertension had significantly lower Km (P < 0.05) values and raised membrane microviscosity measured by 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene anisotropy (P < 0.05) compared with patients without a family history of hypertension. 4. Uraemic subjects had low K(m) values compared with patients with renal disease and normal renal function (P < 0.05). However, there was no significant difference in membrane microviscosity between uraemic and non-uraemic subjects. 5. In patients with a family history of hypertension, sodium-lithium countertransport activity and 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene anisotropy are important markers of cellular changes in essential hypertension, independent of renal disease. Uraemia, independently of hypertension, produces an alteration in the function of the sodium-lithium countertransporter which has previously been associated with a genetic predisposition to hypertension and cardiovascular disease.

Salmonella arizona infections in Latinos associated with rattlesnake folk medicine.

In 1987 two Los Angeles County (California) hospitals reported four Latino patients with serious Salmonella arizona (Salmonella subgroup 3) infections who gave a medical history of taking rattlesnake capsules prior to illness. Capsules supplied by the patients or household members grew Salmonella arizona. We reviewed surveillance data for this Salmonella species and conducted a case-control study to determine the magnitude of this public health problem. Eighteen (82 percent) of the 22 Latino cases in 1986 and 1987 who were questioned reported ingesting snake capsules compared to two (8 percent) of 24 matched Latino controls with non-subgroup 3 salmonellosis or shigellosis (matched pair odds ratio = 18.0, CI = 4.2, 76.3). An average of 18 cases per year of Salmonella arizona were reported in the county between 1980 and 1987. In this investigation the majority of S. arizona cases reporting snake capsule ingestion had underlying illnesses such as acquired immunodeficiency syndrome (AIDS), diabetes, arthritis, cancer. The capsules were obtained primarily from Tijuana, Mexico and from Los Angeles, California pharmacies in Latino neighborhoods. Despite publicity and attempts to remove the capsules from sale in California, Salmonella arizona cases associated with snake-capsule ingestion continue to occur.

Plasma amino acid profile in the elderly with increasing uraemia.

Abnormalities in plasma amino acid profiles have been reported in severe uraemia and dialysis patients and may be a consequence of altered protein metabolism in the presence of metabolic acidosis. We studied plasma amino acid profiles in 7 control subjects [GFR 92.7 +/- (SEM) 14.5 ml/min/1.73 m2] and 7 elderly patients with renal failure (GFR 16.5 +/- 1.3 ml/min/1.73 m2). Uraemic patients had significantly reduced plasma levels of valine, tyrosine, phenylalanine, tryptophan and elevated histidine compared to controls. There was no correlation between arterial pH or bicarbonate and plasma amino acid levels.