Evaporation of seawater: calculated mineral sequences

Van't Hoff's predictions of the mineral sequences to be expected on the evaporation of seawater are based on an oversimplified system. New computer calculation that include calcium-bearing phases are in better agreement with natural occurrences, removing discrepancies that have plagued evaporite geologists for nearly a century. A new hydrologic model that combines equilibrium batch evaporation with fractionation between successive batches is proposed to account for the mineral sequences observed in such classic deposits as the German Zechstein.     

Abnormalities of the Thoracic Bellows: Stress Fractures of the Ribs and Hiatal Hernia

The thoracic bellows mechanism consists of the rib cage and the diaphragm. The purpose of this study was to determine if nontraumatically acquired lesions of the bellows were secondary to underlying disease. Abnormalities of the bellows, specifically stress fractures of the ribs and hiatal hernia, were found in 21 dogs and cats with underlying cardiopulmonary disease, neuromuscular disease, or metabolic disease. A case-control study of Bulldogs demonstrated that hiatal hernia was associated with the more severe manifestations of brachycephalic syndrome. Stress fractures occurred mostly in females and in cats, and involved multiple ribs. Fractures were usually related to severe respiratory effort, but also occurred in association with metabolic disease. Hiatal hernia was also associated with severe respiratory effort, but may be exacerbated if a neuromuscular disorder affecting the diaphragm is present. Abnormalities of the thoracic bellows, such as rib stress fractures and hiatal hernia, may be signs of underlying disease, rather than being primary causes of disease.     

Influence of soil properties on the aggregate stability of cultivated sandy clay loams

Purpose

Frequent cultivation and overhead irrigation have led to severe surface crusting, erosion and poor irrigation performance on sandy clay loam soils in the Coal River Valley, Tasmania, Australia. This study was established to identify the key soil properties related to aggregate breakdown determined by different methods, and explore options for reducing soil crusting.

Materials and methods

Soil aggregates were collected from 0 to 5 cm depth from 20 sites managed for packet salad and lettuce production. The stability of air-dried 2.00–4.75 mm aggregates was determined by rainfall simulation, wet sieving and clay dispersion. Soil aggregates were analysed for particle size, mineralogy, soluble and exchangeable cations, pH, EC, labile carbon and total carbon. The association between aggregate stability and the measured soil properties was explored using Spearman correlation, linear regression and regression tree analysis.

Result and discussion

Aggregate stability determined by rainfall simulation was closely associated with soil properties that promote aggregation, including effective cation exchangeable capacity (ECEC) and the proportion of polyvalent cations (Ca²⁺, Al³⁺). In contrast, aggregate stability determined by wet sieving was associated with soil properties that promote disaggregation, including quartz and sand content, and to lesser extent, the proportion of monovalent cations (especially K⁺). Clay dispersion was closely associated with pH, quartz content, soil texture and the sodium adsorption ratio. Soil carbon appeared to have only moderate influence on aggregate stability, but not clay dispersion, while labile carbon was not significantly related to any measure of aggregate stability or clay dispersion. Similarly, the proportion of Na⁺ ions was not related to either measure of aggregate stability and was only moderately related to clay dispersion.

Conclusions

Options for improving aggregate stability appear limited as aggregate stability was strongly related to the content of inherent soil properties such as sand/quartz and smectite contents. However, high correlation between exchangeable Ca²⁺ and aggregate stability determined by rainfall simulation indicates that soil crusting may be reduced through application of products that rich in Ca²⁺ such as gypsum.

     

Amyloidosis in a dog: treatment with dimethylsulfoxide

A dog with hypoalbuminemia, proteinuria, and renal amyloidosis was treated with dimethylsulfoxide for 2 years. During a 1-year period, serum albumin concentrations increased to within normal range. The 24-hour urinary protein excretion was 5.7 g before treatment with dimethylsulfoxide. Two years after initiation of treatment, the 24-hour urinary protein excretion was 3.7 g. Removal of a testicle containing a Sertoli cell tumor and treatment of interdigital pyoderma may have been factors in the dog's clinical improvement. The only adverse effect from the dimethylsulfoxide treatment was the characteristic disagreeable odor.     

Clinical evaluation of a right-sided prophylactic gastropexy via a grid approach

A new technique is described for a prophylactic incisional gastropexy via a right-sided grid approach (i.e., minilaparotomy). A pilot study showed comparable tensile strength between a traditional ventral midline approach and the grid approach. Six client-owned dogs were selected for the procedure. Four weeks postoperatively, a barium gastrogram was performed to assess stomach/gastropexy position. Complications included a seroma and postoperative discomfort. This technique should be considered for any at-risk breed that is not overweight. The right-sided grid approach to a prophylactic gastropexy was less invasive than a ventral midline approach and resulted in a stable gastropexy at 4 weeks postoperatively in five of six dogs.     

Spontaneous pneumothorax caused by pulmonary blebs and bullae in 12 dogs

Spontaneous pneumothorax caused by pulmonary blebs and bullae was diagnosed in 12 dogs based on history, clinical examination, thoracic radiographs, surgical findings, and histopathological examination of resected pulmonary lesions. Radiographic evidence of blebs or bullae was seen in only one dog. None of the dogs responded to conservative treatment with thoracocentesis or thoracostomy tube drainage. A median sternotomy approach was used to explore the thorax in all dogs. Pulmonary blebs and bullae were resected with partial or complete lung lobectomy. Ten of the dogs had more than one lesion, and seven of the dogs had bilateral lesions. The cranial lung lobes were most commonly affected. Histopathology results of the blebs and bullae were consistent in all dogs and resembled lesions found in humans with primary spontaneous pneumothorax. None of the dogs developed recurrence of pneumothorax. Median follow-up time was 19 months. The outcome following resection of the pulmonary blebs and bullae was excellent.     

Effect of time of cisplatin administration on its toxicity and pharmacokinetics in dogs.

Cisplatin (90 mg/m2) was administered in a 5-minute bolus IV infusion to dogs at 8 AM (n = 6) or 4 PM (n = 6). Blood and urine samples were collected over a 4-hour period for statistical moment pharmacokinetic analysis. Mean urinary excretion rate of total platinum was increased, whereas mean plasma residence time of ultrafilterable platinum was decreased, in the group treated at 4 PM (PM group), compared with those treated at 8 AM (AM group). Over a 2-week postinfusion-monitoring period, both groups of dogs developed decreases in creatinine clearance, urine/serum osmolality ratio (UOsm/SOsm), specific gravity, and increase in BUN, serum creatinine concentration, urine gamma-glutamyltranspeptidase/urine creatinine ratio (UGGT/UCr), fractional excretion of magnesium, and fractional excretion of phosphate. Urine specific gravity and UOsm/SOsm were significantly decreased, whereas UGGT/UCr and BUN were significantly increased in the AM group, compared with the PM group. The time of administration had a significant effect on the pharmacokinetics of cisplatin, which resulted in significant differences in cisplatin-induced renal toxicosis.     

Preservation versus excision of the ileocolic junction during colectomy for megacolon: A study of 22 cats

From 1984 to 1991, 22 cats with megacolon underwent colectomy by end-to-end anastomosis of the distal colon to either the proximal colon (preserving the ileocolic junction in 14 cats) or to the distal small intestine (excising the ileocolic junction in eight cats). During the postoperative adaptive period, the two groups showed similar stool consistency, and the presence of either anorexia, lethargy, weight loss or diarrhoea with faecal incontinence. During the long term post-operative adaptive period, no significant difference in recurrent constipation was found between the two groups. The overall constipation rate after colectomy was 45 per cent (10 cats), and because of constipation recurrence 18 per cent (four cats) were euthanased, and 18 per cent (four cats) required further surgery. Long term following colectomy, those cats which under-went excision of the ileocolic junction had significantly looser stools than those cats in which the ileocolic junction was preserved. The preservation of the ileocolic junction during colectomy is therefore recommended.     

Feline Musculoskeletal Pain Index: Responsiveness and Testing of Criterion Validity

Background

Progress in establishing if therapies provide relief to cats with degenerative joint disease (DJD)‐associated pain is hampered by a lack of validated owner‐administered assessment methods.

Hypothesis

That an appropriately developed subjective owner‐completed instrument (Feline Musculoskeletal Pain Index‐FMPI) to assess DJD‐associated impairment would have responsiveness and criterion validity.

Animals

Twenty‐five client‐owned cats with DJD‐associated pain.

Methods

FMPI responsiveness (ability to detect the effect of an analgesic treatment) and validity (correlation with an objective measure) were explored through a stratified, randomized, double blinded, placebo‐controlled, crossover 10‐week clinical study. Meloxicam was administered to effect pain relief. A linear mixed model, backward stepwise regression, and Pearson correlations were used to assess responsiveness and criterion validity with the assumption that the NSAID would increase activity.

Results

Positive responses of cats to placebo (P = .0001) and meloxicam treatment (P = .0004) were detected; however, the instrument did not detect any difference between placebo and meloxicam (linear mixed model), even for the high impairment cases. Percent meloxicam target dose administered, temperament, and total baseline FMPI score were covariates that most affected FMPI scores. Controlling for significant covariates, most positive effects were seen for placebo treatment. Positive treatment effects on activity were detected, but only for the cases designated as most highly impaired.

Conclusions and Clinical Importance

Neither responsiveness nor criterion validity were detected by the inclusion criteria for cases in this study. The data suggest that further work is indicated to understand factors affecting activity in cats to optimize inclusion criteria.