Limited historical admixture between European wildcats and domestic cats

Domestic cats were derived from the Near Eastern wildcat (Felis lybica), after which they dispersed with people into Europe. As they did so, it is possible that they interbred with the indigenous population of European wildcats (Felis silvestris). Gene flow between incoming domestic animals and closely related indigenous wild species has been previously demonstrated in other taxa, including pigs, sheep, goats, bees, chickens, and cattle. In the case of cats, a lack of nuclear, genome-wide data, particularly from Near Eastern wildcats, has made it difficult to either detect or quantify this possibility. To address these issues, we generated 75 ancient mitochondrial genomes, 14 ancient nuclear genomes, and 31 modern nuclear genomes from European and Near Eastern wildcats. Our results demonstrate that despite cohabitating for at least 2,000 years on the European mainland and in Britain, most modern domestic cats possessed less than 10% of their ancestry from European wildcats, and ancient European wildcats possessed little to no ancestry from domestic cats. The antiquity and strength of this reproductive isolation between introduced domestic cats and local wildcats was likely the result of behavioral and ecological differences. Intriguingly, this long-lasting reproductive isolation is currently being eroded in parts of the species' distribution as a result of anthropogenic activities.

Microcirculation of the juvenile knee in chronic arthritis

In order to investigate pathogenetic factors in growth abnormalities of the knee in hemophilic arthropathy and juvenile rheumatoid arthritis, the hemodynamic changes of the knee following chronic synovial inflammation and elevated joint pressure were studied in puppies. Unilateral arthritis was induced by intraarticular injections of carrageenan solution. Regional blood flow (RBF) was measured by tracer microsphere technique. Microvascular volume (VV) was estimated from the distribution volumes of Cr51-labelled erythrocytes and I125 fibrinogen. Mean transit times (TT) of blood components were calculated from volume/flow ratios. The arthritic joint capsules were characterized by high RBF rates, increased VV, low tissue hematocrit (HCT) and short TT of blood. In the juxtaarticular epiphyses and the patella, RBF was largely unchanged, whereas VV was significantly elevated and TT of blood prolonged. The growth plates formed borders for the extension of these changes. The increased permeability and surface area between blood and bone in arthritis may accelerate the resorption and subsequent destruction of subchondral bone in chronic arthropathies of the juvenile knee.

Gallbladder emptying and gastrointestinal cyclic motor activity in humans

The purpose of the present work was to answer two questions: does the human gallbladder empty in the fasting state, and, if so, is the emptying related to a specific phase of the activity in the gastrointestinal tract? The material consisted of nine healthy volunteers and the motility recordings were done with a perfused low-compliance system. Gallbladder emptying was recorded by the use of scintigraphy with 99mTc-HIDA. Eleven activity fronts were observed, and seven periods of gallbladder emptying were recorded. Reduction in counts over the gallbladder ranged from 8% to 32%. All emptyings took place in connection with phase-II activity in the intestine. Three were in close proximity to the following phase-III activity, and the other four occurred early in a phase II. Four activity fronts were not accompanied by output of bile.

CONCLUSIONS

bile output from the gallbladder occurs in fasting humans, and gallbladder emptying takes place in connection with phase-II activity in the intestine but not always in close connection with the following phase-III activity.

Haemodynamics in acute arthritis of the knee in puppies

In order to study the haemodynamic changes of the juvenile knee in acute arthritis, an experimental model was developed in puppies by unilateral intra-articular injections of Carragheenin solution into the knee. Tissue blood flow was studied by the tracer microsphere technique in eight dogs and simultaneous intra-articular and intraosseous pressure recordings were performed in seven other dogs. The intra-articular pressure was elevated in all arthritic knees. Hyperaemia was found in the knee-joint capsule and distal femoral metaphysis, whereas juxta-articular epiphyseal blood flow rates were not significantly changed. A decrease of femoral muscle blood flow was encountered. Intraosseous pressure recordings during venous tamponade of the knee-joint capsules suggested a qualitative change of bone vasculature in acute arthritis. The juxta-articular bone blood flow in arthritis appears to be influenced by synovial hyperaemia, synovial effusion pressure, an "inflammatory resistance factor" and the anatomical relationship of the epiphyseal vessels to the knee-joint capsule.

Hemodynamics of the juvenile dog knee in relation to increased venous outlet resistance

Tissue blood flow was measured by the tracer microsphere technique in the juxta-articular bones of the immature knee, knee joint capsule and skeletal muscles of the hind limbs after unilateral bone cannulation of the distal femoral epiphysis, surgical exploration of the popliteal vessels and unilateral isolated increase of venous outlet resistance in the distal femoral epiphysis during Halothane anaesthesia. Pressure registration was performed in a liquid-filled electromanometric pressure recording system. Significant regional differences in bone blood flow was found within the different bone compartments of both control and test limb. Bone cannulation resulted in insignificant hyperaemia in the distal femoral epiphysis. No changes of distribution pattern of bone blood flow followed the surgical procedure. Ligation of the medial genicular vein caused a three fold increase of venous outlet resistance measured after 5 min, while an insignificant decrease of arterial inlet resistance was calculated. After one hour a significant decrease of both arterial inlet resistance and venous outlet resistance was found. In addition evidence of a veno-arterial reflex mechanism causing a significant unilateral decrease of distal skeletal muscle blood flow was found. The results demonstrate the presence of both venous and arterial regulation, predominantly metabolic, of bone blood flow in the knee.

Relationship between intraosseous pressures and intra-articular pressure in arthritis of the knee. An experimental study in immature dogs

The influence of chronic synovial inflammation and effusion on the juxta-articular bone haemodynamics in the juvenile knee was studied in 12 immature dogs with Carragheenin-induced unilateral arthritis. Using a fluid filled electromanometric pressure recording system simultaneous pressure measurements were taken from the distal femoral metaphysis, juxta-articular epiphyses and knee joint cavity in general anaesthesia followed by intraosseous phlebographies. During resting conditions the intraosseous pressure of the distal femoral epiphysis and the intra-articular pressure was significantly elevated. The phlebographies showed increased accumulation of contrast in arthritic femoral epiphyses with decreased contrast clearance rate. During increasing intra-articular pressure an augmented vulnerability of the blood supply of the arthritic femoral epiphyses was demonstrated. The results suggests that joint effusion may play an important role in the bone changes in juvenile degenerative arthritis of the knee.

Blood flow in the juvenile hip in relation to changes of the intraarticular pressure. An experimental investigation in dogs

The blood flow in the hip joint of puppies was studied by means of the microsphere technique. The flow was determined before, during and after intraarticular pressure increase. A venous tamponade of 50 mmHg resulted in a significantly reduced flow in the femoral head and after an arterial tamponade of 150 mmHg the flow almost ceased. The proximal femoral metaphysis, the acetabulum and the hip joint capsule, on the contrary, showed varying degrees of flow increase. It is suggested that the significantly increased blood flow in the hip joint capsule during the intraarticular pressure increase of 50 mmHg and 150 mmHg is caused by an autoregulatory mechanism tending to restore the blood flow in the suffering femoral head. The demonstrated disturbance of the circulation in the juvenile femoral head after venous tamponade supports the theory that synovitis may be the basic mechanism in the production of Calvé-Legg-Perthes' disease.

Hemodynamics of the juvenile knee in relation to increasing intra-articular pressure. An experimental study in dogs

The relationships between intraosseous pressure and regional blood flow in the juxta-articular epiphyses were determined in the knees of immature dogs. Intraosseous pressures were continuously registered in one knee. Regional blood flow rates were simultaneously determined by the microsphere technique before and after venous tamponade of both knee joint capsules. During complete venous tamponade the intraosseous pressure of the distal femoral epiphyses rose 268%, while flow increased 122%. A concurrent 20-fold flow increase of the knee capsule and 3-4-fold flow increase of the proximal femoral bone was observed. Evacuation of the knee joints resulted in an immediate drop of the intraosseous pressure of the distal femoral epiphyses, whereas hyperaemia prevailed for at least half an hour and was most pronounced in the distal femoral epiphyses and knee joint capsule. Intraosseous pressure registration did not significantly influence regional blood flow. It is suggested that the changes of intraosseous pressures during knee joint tamponade reflect changes in the venous outlet resistance. The results demonstrate the significance of intra-articular pressure increase on the hemodynamics of the juxta-articular tissues of the knee and proximal femoral bone. These findings may be of importance in the pathogenesis of growth disturbances observed in juvenile degenerative arthritis.