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Biomedical subjects

D K Hinkle

Publications and source records attributed to D K Hinkle.

10 recordsLinked to original sources
PubMed1994

Cryopreservation of articular cartilage. Ultrastructural observations and long-term results of experimental distal femoral transplantation.

Ultrastructural changes associated with the freeze-preservation of human articular cartilage have been investigated and related to changes in transplanted distal femoral allografts in nonhuman primates. Human osteoarticular specimens were frozen at 2 degrees/minute in the presence of 15% glycerol and kept in liquid nitrogen freezers (vapor phase) from one day to two years. Ultrastructural changes were confined primarily to chondrocytes and were related to the freezing phenomenon, not to the time of storage. The cartilage matrix was affected little, explaining why articular cartilage initially survives clinical transplantation, but later undergoes degenerative changes. Osteoarticular allografts of baboons were frozen in an identical fashion to the human articular cartilage and transplanted into adult baboons. Long-term observations (five years) on these animals showed healing and replacement of the osseous portion of cryopreserved allografts. Fractures that appeared to coincide with maximum revascularization of the graft were the principal complication. Articular surfaces of the cryopreserved allografts underwent degenerative changes over five years. These degenerative changes were also manifested radiologically and appeared similar to those observed in humans. By contrast, fresh osteoarticular allografts healed poorly through fibrous union. However, in one of two fresh allografts, the articular cartilage remained intact five years after transplantation.

Adolescent↗
PubMed1987

Glomerular filtration rate and blood pressure monitoring in awake baboons.

Minimally invasive techniques were used to collect urine with an external catheter together with automated intermittent monitoring of arterial blood pressure in awake male baboons. Using endogenous creatinine, 24-hour creatinine clearances were measured for 2 to 3 consecutive days in four intact and in four uninephrectomized baboons. Despite large differences in urinary volume and sodium excretion, reproducibility of 24-hour creatinine clearances was within 15% in 15 of 19 studies obtained from 6 of 8 animals. Arterial blood pressure was monitored intermittently at 30 to 60 minute intervals over 24 hours with a Dinamap monitor and recorder. Mean blood pressure averaged 71 +/- 4.4 to 89 +/- 5.5 mm Hg in different animals. Blood pressure tended to be lower at night than during the day. In separate studies using 15 to 60 minute urine collection periods, inulin clearance was compared in awake and in anesthetized animals with endogenous or exogenous creatinine clearance measured simultaneously. The clearance of creatinine systematically exceeded the clearance of inulin, even in intact animals with a normal serum creatinine. The creatinine-to-inulin clearance ratio averaged 1.16 +/- 0.03 at a serum concentration of 0.7 to 0.8 mg/dl; 1.27 +/- 0.03 at a serum creatinine of 1.0 to 1.1 mg/dl and 1.56 +/- 0.04 at a serum creatinine greater than 10 mg/dl. All values exceed unity significantly (p less than 0.001). Thus, renal function, including inulin clearance, can be measured in awake baboons. Duplicate or triplicate 24-hour urine collections are needed to assess the reliability of creatinine excretion. However, creatinine clearance overestimates glomerular filtration rate, as it does in humans.

Animals↗
PubMed1980

Maturation of normal primate cerebral tissue: preliminary results of a computed tomographic-anatomic correlation.

Preliminary results of experimental cerebral computed tomography densitometric studies in newborn primates (baboon) indicate that (a) at birth the white matter of the frontal lobe is hypodense compared to the white matter of the parietal and occipital areas, (b) the white matter becomes increasingly dense with age, and (c) at 1 year of age the white matter in the frontal, parietal, and occipital areas of the brain becomes nearly equal in density. The ongoing myelinization process is considered to be one of the critical factors in these developmental changes.

Animals↗
PubMed1980

Environmental and biological effects following application of diazinon impregnated strips within a laboratory animal room.

Rats were exposed to diazinon impregnated strips in a conventional laboratory animal room. The air in the room was monitored for the pesticide. Erythrocyte acetylcholinesterase and plasma pseudocholinesterase activities were determined periodically. Air concentration of the pesticide never exceeded 1.34 microgram/m3. No significant change in enzyme activities were observed.

Acetylcholinesterase↗