Biomedical subjects
Publications and source records attributed to R W Brown.
Two cases of renal medullary necrosis in young infants demonstrated on excretory urography are reported. 24 cases of renal medullary necrosis in children recognised at autopsy at the Royal Alexandra Hospital for Children between 1953 and 1977 are reviewed. Radiologists should be aware and in search of this entity in all children with history of kidney hypoxia.
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Four dairy cows were stressed by exposure to hot and cold environments in tests to determine the effect of environment on milk yield, somatic cell counts, and California mastitis test scores of milk from all mammary quarters and on bacterial counts of milk from infected quarters. Two cows were held in temperature-controlled rooms for successive 5-day periods at moderate (21 to 28 C), cold (-16 C), moderate, hot (36 to 37 C), and moderate environments. The cold and hot sequences were reversed for the other 2 cows. Temperature transmitters were surgically implanted in the skeletal muscles of the loin and gluteal regions; however, only one of these transmitters (gluteal region) functioned continuously throughout the experiment. At the end of this experiment, a transmitter was implanted in the gland cistern of a rear quarter of 1 cow, and the sequence of holding in the cold before the hot environment was used. Mean body temperature was approximately 1 degree higher (39.2 C) in the hot room (1 cow) and 3 to 4 degrees lower (35 C and 33 C), respectively, for 2 cows) in the cold room than that during the moderate temperature periods. A similar comparison showed that the mean intramammary temperature was 1 to 2 degrees higher (39.5 C) in the hot room and approximately 9 degrees lower (29.4 C) in the cold room. Exposure of the cows to hot and cold environments caused a greater loss in milk production in the 2 medium-yielding cows (23 to 28 kg/day) than in the 2 low-yielding cows (9 to 13 kg/day). The effect of the extreme temperatures on the somatic cell counts in uninfected quarters was limited to only a few quarters and was inconsistent (mean counts increased and decreased at both temperatures). The California mastitis test reactions showed no consistent changes during periods of heat and cold stress. Also, the effect of the environmental temperature on the intramammary infections also was inconsistent. The effect on bacterial counts appeared to vary with the type of organism. Some mean counts decreased in the heat and cold (Streptococcus agalactiae, Micrococcus sp), some increased (Pseudomonas sp), and another seemed independent (Streptococcus uberis) of the environmental temperature at which the cow was held.
The growth of Streptococcus agalactiae in milk is inhibited by elevated free isoleucine. Free amino acid concentrations in both plasma and milk from three lactating dairy cows were studied after intravenous infusions of L-isoleucine at 62, 300, 380, and 840 mumol/kg of body weight. Free isoleucine was lower in milk than in plasma. The concentration of free isoleucine in plasma increased after infusions of isoleucine at the three higher amounts. The highest concentration of free isoleucine in milk measured was 1.5 mumol/100 ml of skin milk. This was observed after infusion of isoleucine for 12 h at 380 mumol/kg of body weight. Free isoleucine in both plasma and milk dropped to the preinfusion concentrations a short time after the isoleucine infusions were stopped. When relatively large quantities of isoleucine were infused into the blood of cows, free isoleucine in blood increased as much as twofold. The source of free isoleucine in milk appeared to be free isoleucine in plasma, but isoleucine in milk only reached concentrations that would give about 50% of the growth inhibition of S. agalactiae obtainable with isoleucine in vitro. It would be difficult to elevate free isoleucine in milk by dietary manipulation sufficiently to inhibit S. agalactiae.
Wheys of milk and colostrum were treated with ethanol and the concentrated supernatant fluids were subjected to chromatographic procedures (anion exchange resin, using distilled water as eluent). The fractions were tested for capabilities to stimulate the growth of Streptococcus agalactiae in a mixture (1:32) of pasteurized milk and steamed milk. Three stimulatory factors (F), designated F-1, F-2, and F-3, were separated; F-1 was nonionic, and F-2 and F-3 were cationic. A mixture containing any 2 factors gave greater stimulation than either factor tested alone, and a mixture of all 3 gave the greatest stimulation. The F-2 activity was attributed to cystine.
Nonspecific immunosuppression of transplant patients frequently leads to complications which might be circumvented by inducing donor-specific immune unresponsiveness. Such specific immunosuppression has been produced experimentally, with use of donor antigen and antilymphocyte serum (ALS) for active enhancement. A case is presented in which the recipient of a cadaveric renal allograft (zero antigen match, cross-match negative) was given ALS (first 14 days after operation) and 11 X 10(9) donor bone marrow cells (twenty-fifth postoperative day) along with conventional doses of prednisone and Imuran in an attempt to produce donor-specific immune unresponsiveness. There were no rejection episodes, and serum creatinine remained less than 1.0 mg. per 100 ml. By the second month after transplantation there was no evidence for the persistence of donor erythrocytes or white cells. The conventional immunosuppressive agents were tapered and renal function was normal 8 months after transplantation, when the patient developed fatal peritonitis secondary to perforated sigmoid diverticulitis. At autopsy the renal allograft showed only minimal evidence of rejection. The present case illustrates an attempt to use ALS and donor bone marrow cells for active enhancement of a human cadaveric renal allograft. The infusion of stored donor marrow cells after transplantation is a particularly applicable technique for human cadaveric organ transplantation. The rejection-free course of this patient suggests that attempts to produce active enhancement clinically deserve further trial.
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The electrophoretic separation of the proteinases produced by staphylococci and micrococci was studied in four buffers. The duration of electrophoresis was based on the migration of a marker dye for a predetermined distance. The migration distances of the enzymes and dye were measured, and enzyme-dye values were calculated. A comparison of enzyme-dye values showed that complete separation of eight serologically different proteinases did not occur in any one buffer; however, in most instances, their relative order of migration was the same in all buffers. Certain strains of Staphylococcus epidermidis produced two proteinases that were different serologically as well as electrophoretically. Staphylococcus aureus strains, on the other hand, produced up to four proteinases that were serologically the same. The proteinases of staphylococci and micrococci can be best characterized by both electrophoretic and serological methods.
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The naturally occurring (nonspecific) proteinase inhibitor which occurs in the alpha globulin fraction of immune rabbit serum was separated from specific staphylococcal and micrococcal antiproteinases by treatment of the antiserum with 2-ethoxy-6-9-diaminacridine. The 2-ethoxy-6-9-diaminacridine-treated serum could then be used to classify these bacterial proteinases by testing directly on casein agar without prior electrophoresis of the serum.
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