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Biomedical subjects

J C Russell

Publications and source records attributed to J C Russell.

At least 163 records · Page 9Linked to original sources
PubMed1981

Effects of histamine and antihistamines on the kinetics of carbon dioxide in the rat.

We have investigated the effects of chlorpheniramine (an H1 histamine inhibitor) and metiamide (an H2 inhibitor) on response to 14C pulse-labeling of carbon dioxide in the rat in the presence and absence of histamine. Neither chlorpheniramine nor metiamide alone had any effect upon the gastric venous/arterial ratio (VG/A) or the peripheral venous/arterial ratio (Vp/A). As in the case with no drug present, Vp/A rose with time following pulse-labeling to a value of 1.15-1.20. The presence of a preexisting steady-state infusion of histamine caused no changes in the ratios in the presence or absence of the inhibitors. The inhibitors did completely abolish the oscillations of both VG/A and Vp/A caused by initiation of histamine infusion coincident with the pulse-labeling. The results suggest that the histamine effects are largely mediated through H1 receptors.

Animals↗
PubMed1981

Mycotic emboli of the peripheral vessels: analysis of forty-four cases.

Two cases of mycotic emboli of the peripheral vessels are presented, and 42 additional cases from the literature are analyzed. Male patients predominate 3:1. Candida and Aspergillus are the usual pathogens. Initial presentation as large vessel peripheral emboli is characteristic (77%), with emboli originating from either the aortic or mitral valves. Cerebral emboli may proceed of follow the peripheral embolization. Predisposing factors include open-heart surgery, antibiotic therapy, concomitant infection, and intravenous drug abuse. Early symptoms of fungemia are nonspecific, with blood cultures positive in only 43% of cases. The overall mortality rate was 84%-73% in patients who did not undergo previous open-heart surgery, and 96% in patients who underwent previous open-heart surgery. Patients with Candida infection seem to do better than those with Aspergillus endocarditis (19% survival versus 5%). Aggressive therapy, including embolectomy, early valve replacement, and prolonged antifungal drug therapy, is advised.

Adult↗
PubMed1980

Small-animal ergometer.

A continuous vertical ladder ergometer for small animals has been developed. This device, operating at a (variable) downward velocity, obliges the subject animal to climb continuously, thus imposing a steady quantifiable work rate or power output. The power output of the animal is given simply by P = W X V X 9.80 X 10(-3) sin theta, where P is the power output in watts, W the animals' weight in grams, V the ladder velocity in meters per second, and theta the angle between horizontal and the ladder surface. Wistar rats have been readily taught to climb on the ergometer and demonstrate high levels of physical effort with no injuries. Rats of 350 g body wt are able to climb at 0.25 m/s for period of 15 min. The maximal power output of rats varies between 0.5 and 1.1 W. The ergometer design is compatible with conditioning and exercise programs for small animals as well as with quantitative measurements of power output and physiological parameters such as heart rate and gas exchange.

Animals↗
PubMed1980

Carbon dioxide balance in rat stomach and peripheral tissue: effects of histamine.

Total carbon dioxide content of arterial, gastric venous, and peripheral venous blood of the rat has been measured by a gas extraction-gas solid chromatographic technique. In control animals total contents were 24 to 29 mmol/l and the venous/arterial ratio 1.148 +/- 0.020 (xav +/- SEM). Net change of carbon dioxide content (delta CO2) was 1.17 +/- 0.56 and 1.11 +/- 0.45 mmol/l in gastric and peripheral circulations and these were not significantly different from each other or zero. Infusion of histamine at 10 mg/kg/h led to oscillations in delta CO2 with peaks as high as 4.7 mmol/l and a period of 20 min. Similar oscillations occurred in the venous/arterial ratio with values up to 1.35. The results confirm previous reports of oscillations of carbon dioxide venous/arterial ratios induced by histamine as revealed by pulse radiolabeling experiments. The positive, if oscillatory, carbon dioxide balance in the presence of histamine supports the concept of sequestration of carbon dioxide in tissue with subsequent release on histamine stimulation.

Acid-Base Equilibrium↗
PubMed1979

Operative management of radiation injuries of the intestinal tract.

A review of forty cases of radiation-induced gastrointestinal injuries is presented. Based on this experience and reports in the literature, preoperative management and operative technics are discussed. The increased risk of radiation bowel injury is recognized in patients who have had previous operations. Preradiation contrast studies are advised to identify trapped loops of intestine in the pelvis. Small bowel resection is recommended with localized segments of disease. Bypass operations are preferable to avoid any extensive dissections. Bypass operations have anastomotic dehiscence rates similar to those of resections. Proctocolitis is usually managed by diverting colostomy, with resection in a few favorable cases or with treatment failures. Most rectovaginal fistulas are managed by permanent colostomy. Small bowel fistulas are best treated by bypass with partial or total exclusion rather than by primary resection. Vigorous preoperative and postoperative nutritional support and evaluation are vital because of the poor healing qualities of irradiated bowel. Multiple operative procedures should be anticipated because the natural history of radiation bowel injury is slowly progressive.

Aged↗
PubMed1979

Urine production in the halothane anesthetized rabbit.

Urine and blood parameters were studied in rabbits subjected to anesthesia and abdominal surgery. Conscious control animals both fasted and fed to which water was freely available were used for comparison. During anesthesia and operation one group of animals were given no intravenous fluid, other groups were infused with normal saline at a rate of 0.5 ml, 1 ml, or 2 ml per minute. The results demonstrated that an intravenous saline infusion of 0.5 ml per minute, maintains an essentially normal state of hydration and is beneficial to rabbits during anesthesia and surgery. However, with such an infusion, the rabbits do not produce urine under the experimental conditions. Higher rates of infusion are associated with a declining heart rate and blood pressure, abnormal urine, and metabolic acidosis. We conclude that the rabbit is an inappropraite species for renal studies involving anesthesia and surgery.

Animals↗
PubMed1978

Aggregation of binding protein from rat nerve.

Leucine-binding protein described in an earlier paper was examined to characterize the dynamic properties of the system. Leucine-binding protein assembles into a large protein polymer or complex (greater than 302,000 daltons). Colchicine reduces and Mg2+ increases the amount of polymer formed. Trypsin destroys the isolated polymer but RNAase and collagenase do not. Mg2+-ATPase activity is present in the polymer fraction. The formation of the large complex suggests a quickly adaptable structure capable of responding to ionic and environmental conditions.

Animals↗
PubMed1977

Determination of the syn-anti equilibrium of some purine 3':5'-nucleotides by nuclear-magnetic-relaxation perturbation in the presence of a lanthanide-ion probe.

The aqueous solution conformation of four purine 3':5'-nucleotides varying in their substituents at C-6 and C-8 has been studied using gadolinium(III) to perturb the proton relaxation times. The ribose conformations are inferred. All the nucleotides are best described as being in a dynamic equilibrium between syn and anti conformations and the position of this equilibrium is not dramatically affected by changing the substituent at C-6. These nucleotides in their neutral base form slightly favour an anti conformation. In the presence of a bulky methylthio group at C-8 the equilibrium is shifted towards a dominance from the syn conformation due to steric repulsion factors.

Binding Sites↗
PubMed1977

A binding protein from rat nerve.

Leucine has been found to bind competitively to a soluble protein (molecular weight 97,000 daltons) from rat sciatic nerve under certain experimental conditions to form a high molecular weight aggregate (MW greater than 302,000). Kinetic study showed that the equilibrium constant for leucine-binding is 1.33 X 10(4) l/m and the rate constants for binding and unbinding are k1 = 0.424 l/m/sec and k-1 = 3.18 X 10(5) sec-1 respectively. The binding reaction is accompanied by an endothermic enthalpy change of 5,000 cal/mole and the favorable equilibrium appears to be due to the large positive (35.3 eu) entropy of binding. L-Proline, thymidine, and succinic acid were also found to bind, non-competitively with leucine, to proteins in the same fraction. Binding of those compounds and leucine was enhanced by the presence of Mg2+. Rat muscle and plasma proteins did not significantly bind leucine under these experimental conditions. The presence of this binding protein in rat nerve suggests an additional mechanism in the metabolism and in the transport of amino acids for incorporation into a protein structure in nerve.

Animals↗
PubMed1977

Effect of histamine upon the dynamics of carbon dioxide.

The dynamics of carbon dioxide in both gastric and peripheral circulation of rat were studied using H14CO3--. In the absence of histamine infusion the peripheral venous/arterial ratio Vp,/A rose from less than 1.0 to almost 1.2 while the gastric ratio VG/A fell from initial values of about 2.4 to 1.2. Steady histamine infusion speeded approach of both ratios to 1.2. During transient conditions after beginning or end of histamine infusion both ratios were initially depressed to values near zero. The ratios then both rose, showing damped oscillations with a twenty-minute period. The data show a marked effect of histamine on both peripheral and gastric CO2 dynamics, even though in the resting state the two circulations have very different dynamics.

Acid-Base Equilibrium↗
PubMed1976

Comparative temperature dependence of (Na+ + K+)-ATPase.

The temperature dependence of (Na+ + K+)-ATPase was measured, utilizing preparations of enzyme from heat and kidney of rats, hamsters, guinea pigs, ground squirrels, turtles, chickens, and ducks. The two hibernating species, hamsters and ground squirrels, were studied awake at normothermia and hibernating at 4 degrees C. The results for every species except the turtles showed the same temperature dependence established for (Na++K+)-ATPase from rabbit kidney with a quasi-linear dependence above 15 degrees C and little or no activity below 15 degrees C. Turtle enzymes showed a broad activity versus temperature curve with a fall-off at high and low temperatures. The data in all cases, including the turtle data, may be fitted by a previously described thermodynamic kinetic model. Further, the model will fith the turnover or decrease in enzyme activity at higher temperatures observed in a number of cases. These results do not support the widely imputed ion pumping role for (Na++K+)-ATPase.

Adenosine Triphosphatases↗
PubMed1975

Biologic effects of airborne particulate lead on continuously exposed rats and rhesus monkeys.

The biological effects of airborne particulate lead were studied in rats and rhesus monkeys (Macaca mulatta) exposed nearly continuously (22 hours per day) at a concentration of 21.5 mug Pb/cubic meter of air. The year-long exposure elicited an increase in the concentration of lead in the blood to 28 mug/100 ml in the rats and 17 mug/100 ml in the monkeys. Levels of lead in control animals were about 5 mug/100 and 4 mug/100 ml, respectively, in the rats and monkeys. The elevated blood-lead levels reached a maximum during the first few months of exposure and did not increase significantly after that time. Elevated concentrations of lead were also detected in lung, liver, kidney and bone of both species. While concentrations of lead were nearly always less than 1 mug/g in control animals, they rose to 2-3 mug/g in soft tissues of exposed animals and up to 6 mug/g in bone. Differences between lead levels in animals exposed six months or twelve months were very small. The concentration of lead decreased in the soft tissues of animals removed from the chamber after one year's exposure but remained elevated in bone. The activity of the enzyme delta-amino-levulinic acid dehydrase (ALAD) in circulating erythrocytes was inhibited about 70% in rats exposed to the airborne lead. No reduction of the enzyme activity occurred in brain or liver tissue of either the rats or monkeys. Normal levels of ALAD in erythrocytes of the monkeys were too low to permit meaningful measurements. In spite of the reduced ALAD activity in rat erythrocytes, there was no concomitant alteration in the excretion of heme precursors. In all other respects, there appeared to be no deleterious effects on the animals from exposure to the airborne particulate lead. No changes were detected in serum chemistry or hematology nor were there any gross, microscopic or ultrastructural pathologic changes observed.

Aerosols↗
PubMed1975

Clinical studies on men continuously exposed to airborne particulate lead.

Two experiments were conducted to determine the effects of low-level exposure to airborne lead particulates on humans. Male volunteers were exposed 23 hours per day for about 18 weeks to either 10.9 mug Pb/m3 or 3.2 mug Pb/m3 of air. The particulate matter consisted primarily of sub-micron sized particles of alpha lead dioxide. During exposure to 10.9 mug Pb/m3, the mean blood-lead level of the men increased to 37 mug/100 ml while the level in controls remained at about 15 mug/100 ml. Exposure to 3.2 mug Pb/m3 elicited an increase in blood-lead to about 27 mug/100 ml. In both cases, the blood-lead levels appeared to plateau after about three months of exposure and subsequent to that, no further increases were observed. About two months after the men left the exposure chamber, their blood-leads returned to near normal levels. Although urinary excretion of lead was always within the limits usually considered normal, there was a definite increase in urinary lead in the men exposed to 10.9 mug Pb/m3 and a somewhat smaller increase in the men exposed to 3.2 mug Pb/m3. The activity of delta-aminolevulinic acid dehydrase was reduced by about 50% in the erythrocytes of men exposed to 10.9 mug Pb/m3, but returned to normal after exposure was terminated. Practically no changes in the activity of the enzyme were noted in the men exposed to 3.2 mug Pb/m3. Exposure to either level of particulate lead did not cause measurable changes in the excretion of heme precursors nor were there any alterations of serum chemistry or hematology profiles in any of the men.

Air↗