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Biomedical subjects

G Hooper

Publications and source records attributed to G Hooper.

At least 55 records · Page 3Linked to original sources

Amputation of the little finger.

We review 17 patients who had 21 amputations of the little finger. Transmetacarpal amputations gave satisfactory results in older patients, but in young patients loss of breadth of the palm caused significant disability. Disarticulation through the metacarpophalangeal joint is recommended in younger patients.

Age Factors↗

Hemangiopericytoma of the median nerve.

This is a case report of a hemangiopericytoma located within the median nerve at the wrist in a 79-year-old man. The tumor was removed without loss of function.

Aged↗

The activity of nitrofurazone and furazolidone against Leishmania donovani, L. major and L. enriettii in vitro and in vivo.

Furazolidone and nitrofurazone showed in vitro activity against amastigotes of Leishmania donovani, L. enriettii and L. major in macrophages, at concentrations which were also toxic to the macrophages. A low grade of activity was observed against L. donovani infections in BALB/c mice by furazolidone but not with nitrofurazone. Nitrofurazone, in two concentrations, was not active when applied to the lesions of cutaneous leishmaniasis due to L. enriettii (guinea-pig infection) or L. major strain P (BALB/c mouse infection). After systemic administration to BALB/c mice infected with L. major strain JISH 252 clone 1, low-grade activity was observed at the highest level tested.

Animals↗

Dislocation of the trapezio-metacarpal joint.

Acute traumatic dislocation of the trapezio-metacarpal joint is not invariably associated with instability of the joint after reduction and the injury should not be considered simply as a "Bennett's fracture without a fracture".

Adolescent↗

Bone blood flow measured with microspheres: the problem of non-entrapment.

Radioactive microspheres were injected into the tibial nutrient arteries of dogs. The validity of their use to measure bone blood flow was tested by examining their concentration in femoral venous blood. Non-entrapment in the tibia was considerable in two animals following rather prolonged alternate periods of perfusion and ischaemia. When such treatment was minimised, non-entrapment was small, showing that in this respect microspheres provide a valid means of measuring bone blood flow.

Animals↗

The pattern of distribution of blood flow in dog limb bones measured using microspheres.

The distribution of blood flow to segments of the leg bones of anaesthetised dogs was studied using radioactive microspheres injected into the heart or the tibial nutrient artery. Following central injection, repeated measurements after an interval showed no change of pattern of distribution. The effects of ligation of the tibial nutrient artery during this interval suggested that 30% of the blood flow to the tibia is normally via this vessel, which predominantly supplies the diaphysis. This deduction differed from that derived from the injection of microspheres during perfusion through a tibial nutrient artery cannula, when half the flow reached the epiphyses. This proportion decreased and the flow to the diaphyseal marrow increased after alternate periods of perfusion and ischaemia, demonstrating the labile nature of bone blood flow distribution.

Animals↗

Occult midtarsal subluxation.

Of 14 patients with navicular tuberosity avulsion, seven had damage to the anterior process of the calcaneum at the calcaneocuboid joint--possibly the result of an occult subluxation of the midtarsal joint. These patients were all middle-aged women who had slipped or fallen a short distance. They were unable to bear full weight because of pain on the medial and lateral aspects of the foot. The associated midtarsal injury was initially missed in five of seven patients because of failure to interpret the radiographic appearance. All seven patients had prolonged symptoms, and three had persistent but not disabling pain at least three years after injury. Degenerative arthritis had developed in the calcaneocuboid joint in four of the five patients at follow-up examinations. Patients with occult subluxation of the midtarsal joint should be managed initially by a period of non-weight-bearing followed by application of a walking cast. The need for early surgical treatment is open to question.

Adolescent↗

The vascular system in bone. Its importance and relevance to clinical practice.

Experimentally proven principles on the effect of changes in bone blood flow on molecular transport in bone and on the factors that affect these changes in both flow under physiologic and pharmacologic conditions clarify the changes that occur in bone in response to certain clinical problems, such as the effect of blood flow in fracture healing. The results of using these principles in establishing a method of quantitative bone scanning are presented.

Animals↗

The variation with flow-rate of the extraction of bone-seeking tracers in recirculation experiments.

Radioactive microspheres were injected into the hearts of anesthetized dogs and the reference organ technique used to determine cardiac output. Blood flow to the leg bones was then obtained from microsphere uptake. Simultaneous injections of the bone-seeking radiotracers 85Sr and, in fewer animals, 18F and 99mTc methylene diphosphonate similarly gave their clearances from the blood by bone over a period of 5 min. The ratio of clearance to flow (extraction ratio) was found to be flow-dependent, falling from near unity at low flow rates to about 0.4 at higher flow rates. The results are in general accordance with the Renkin theory of capillary permeability but do not fit exactly to the concept of a constant product of permeability and surface area, perhaps due to the heterogeneity of the model. The findings confirm conclusions based on tibial nutrient artery perfusion experiments and demonstrate that skeletal blood flow cannot be measured by the clearance of bone-seeking tracers. There were substantial differences of blood flow normalized for weight between the bones of a given animal.

Animals↗

Measurement of tendon blood flow in rabbits by microsphere uptake and 133Xe washout.

Blood flow was measured in the calcaneal tendons of rabbits using the techniques of labelled microsphere uptake and 133Xe washout simultaneously. There was no correlation between the results obtained with the two methods in individual animals. It is doubtful if the assumptions underlying the 133Xe washout technique are valid when it is used to measure blood flow in tendons.

Animals↗

Invalidity of single-passage measurements of the extraction of bone-seeking tracers in rats and rabbits.

Single-passage experiments in which bone-seeking tracers are injected arterially at the same time as microspheres to determine an extraction ratio are only valid if the maximum transit time through bone is less than the minimum recirculation time. This validity was investigated by injecting various intravascular and more diffusible tracers into the hearts or aortas of rats and rabbits at different times before the rapid cessation of circulation. At no time between 4 and 60 s after injection did the bone concentration of any of the tracers fall to negligible values. Removal of unbound tracer is therefore not complete before recirculation starts, and the single-passage technique is invalid. Measurements of bone blood flow based on the clearance of 18F cannot be substantiated, as its extraction is flow dependent.

Animals↗

The early effects of sympathectomy on bone blood flow.

Several laboratories, including our own, have investigated the physiology of bone blood flow by perfusion of the tibia via the nutrient artery. Any damage caused to the nerve supply by cannulation of the artery might affect the results. The possible effect of such damage was investigated by measuring blood flow to the dog tibia using a microsphere technique, before and after sympathectomy. No effect was found and the tibial nutrient artery is therefore a suitable vessel for perfusion when estimating nutrient exchange in bone.

Animals↗