Biomedical subjects
J Nelson
Publications and source records attributed to J Nelson.
Characterization of the (rnunz) nude rat. Morphological characteristics of the lymphoid system.
A nude mutant (rnunz) arose spontaneously in a colony of Wistar albino rats (the wild-type strain) in Wellington, New Zealand. On gross examination no thymus could be found in the mediastina of young animals, whereas in older mutants lobules of fatty tissue mimicked the appearance of the thymus of the wild-type strain. Lymph nodes from the rnunz strain showed a marked lymphocyte depletion in the thymus-dependent para-cortical region of the node. Peyer's patches from the nude animals also showed a reduced density of small lymphocytes in the interfollicular zones. In the spleen, tissue from the reticular framework surrounding individual arterioles was sometimes completely empty of lymphocytes but the degree of depletion varied. Total leucocyte numbers in the rnunz strain were 28% lower than the wild-type strain. In 10 out of 13 animals T cells were less than 3% of the lymphocytes present (wild-type 35% T cells). The findings are in agreement with studies of the Rowett nude rat (rnu) and the nude mouse.
Evaluation of a comprehensive cardiovascular curriculum.
Explore the source record for details and available documents.
Nuclear magnetic resonance spectroscopic method for determination of penicillamine in capsules.
A rapid and specific nuclear magnetic resonance (NMR) spectroscopic method for the determination of penicillamine in capsules is presented. The sample is directly dissolved in D2O and its spectrum recorded on a 90 MHz instrument. The 2 singlets appearing at 1.58-1.64 ppm, due to the nonequivalent gem-dimethyl groups, were integrated and compared with the integral obtained for the phenyl proton signals of sodium saccharin, which is the internal standard. The results obtained by the proposed method closely agreed with those found by the method of USP XX.
The significance of residual disease after radiotherapy in endometrial carcinoma: clinicopathologic correlation.
The extent and location of residual disease after radiotherapy in 91 patients with early invasive endometrial carcinoma was related to tumor grade, clinical stage, and outcome. In 20% the grade (according to the International Federation of Gynecology and Obstetrics) differed in curettage and hysterectomy specimens. In at least 12% the clinical stage was unreliable. Death from endometrial carcinoma was significantly more frequent in patients with residual disease after radiotherapy than in those without residual disease. The poorest prognostic features were blood vesel invasion in the myometrium, irrespective of depth of invasion, and residual disease outside the uterus. Treatment of endometrial carcinoma should be based on accurate knowledge or prognostic features determined by initial surgery.
Rat alveolar macrophages require NADPH for superoxide production in the respiratory burst. Effect of NADPH depletion by paraquat.
Alveolar macrophages can be stimulated by concanavalin A to produce extracellular superoxide. Conflicting opinions exist, however, concerning the relative importance of the oxidation of either NADPH or NADH in the generation of (Formula: see text) by surface membrane-stimulated phagocytic cells. Alveolar macrophages were obtained from adult male rats by lavage with phosphate-buffered saline. Cells (approximately 10(6)/ml) were incubated in Krebs-Ringer phosphate 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid buffer and ferricytochrome c for 15 min at 37 degrees C before addition of concanavalin A. Release of (Formula: see text) was detected as the difference in cytochrome c reduction, followed at 550 nm, in the absence and presence of superoxide dismutase. Superoxide production by concanavalin A-stimulated alveolar macrophages was markedly increased in the presence of glucose but fructose, lactate, and pyruvate were without effect. Paraquat (methylviologen), an oxidation-reduction dye, significantly reduced concanavalin A-stimulated (Formula: see text) production when incubated at 1 mM with alveolar macrophages in the absence of glucose. The effect of paraquat was reversed by glucose, but fructose, lactate, and pyruvate could not reverse paraquat inhibition. Paraquat enhanced oxidation of NADPH (but not NADH) by cell supernatant and increased pentose phosphate shunt activity in resting macrophages, but did not affect mitochondrial respiration or ATP content of alveolar macrophages. These results suggest that paraquat is able to specifically deplete NADPH in alveolar macrophages while not affecting NADH or ATP. Our conclusion is that NADPH is essential for the production of (Formula: see text) by concanavalin A-stimulated alveolar macrophages.
Feeding of caustic-treated grain to cattle.
Explore the source record for details and available documents.
Effects of aspirin and related drugs in vitamin E-deficient rats.
Evidence from the literature indicates that in vitamin E-deficient animals prostaglandin (PG) synthesis in platelets is enhanced while it is decreased in the muscle and testis. In the present study the effects of aspirin, a known inhibitor of PG biosynthesis, on vitamin E deficiency signs in the rat were investigated. Administration of aspirin to vitamin E-deficient rats had no protective effect on fetal mortality, incisor depigmentation, body weight gain or red blood cell peroxidative hemolysis. Aspirin prevented the anemia and thrombocythemia observed in vitamin E-deficient rats. Aspirin, salicylic acid and a carbazole prostaglandin inhibitor exacerbated testis degeneration in vitamin E-deficient animals. Addition of aspirin to the diet more than doubled the vitamin E requirement for reversal of necrotizing myopathy.
Influence of age on the vitamin E requirement for resolution of necrotizing myopathy.
Weanling rats were fed either a vitamin E-deficient diet or the deficient diet supplemented with vitamin E or the antioxidant ethoxyquin. Ethoxyquin was not effective in preventing the elevation in platelet number or percent aggregation. However, ethoxyquin was as effective as vitamin E in maintaining body weight, testes weight, pigmentation of the incisors and in preventing myopathy, observed either histologically or by an elevation in plasma glutamic oxalacetic transaminase (GOT) activity. Removal of ethoxyquin from the diet after 19 weeks of feeding resulted in a rapid onset of myopathy. These observations permitted us to study the requirement for vitamin E at various ages without the complication of any cumulative pathological effects of vitamin E deficiency. Ethoxyquin was deleted from the diet at 8, 20, 44 and 64 weeks of age. The requirement for vitamin E to reduce plasma GOT and pyruvate kinase (PK) activity was measured at 12, 24, 48 and 68 weeks of age. The requirement for vitamin E did not change significantly during this time period.
A micropuncture investigation of electrolyte transport in the parotid glands of sodium-replete and sodium-depleted sheep.
1. Parotid secretion has been studied by micropuncture in sodium-replete and sodium-deficient sheep. 2. The osmolality of unstimulated primary saliva was slightly higher than in plasma and fell following cholinergic nerve stimulation. In sodium-depleted animals the osmolality of final saliva was hypotonic and exhibited flow dependency, where as in sodium-replete animals it was always isotonic. 3. In sodium-replete sheep, the primary fluid sodium concentration was about 120-130 mmol l-1 but in final saliva it was about 167 mmol l-1 and showed little or no flow-dependency. In sodium-depleted sheep, the primary sodium concentration averaged only 82.2 mmol l-1 and it was concluded that sodium-depleted primary fluid contained some other unidentified solute that allowed it to remain approximately isotonic; in final saliva the unstimulated sodium concentration was about 40 mmol l-1 and it rose with increasing flow rate to a maximum of 114.9 mmol l-1. 4. The primary fluid potassium concentration in sodium-replete animals did not differ significantly from that seen in sodium-depleted animals and the values were uninfluenced by stimulation; the over-all mean value was 11.2 mmol l-1. In final saliva, in sodium-replete sheep, the potassium concentrations averaged 7.8 mmol l-1 but in sodium-depleted sheep the concentrations were between 5 and 10 times greater than in primary fluid. 5. It was calculated from the equilibrium pH that the primary bicarbonate concentration would have been about 35 mmol l-1. In final saliva, where bicarbonate was measured directly, the concentrations were much greater and increased with stimulation to about 115 mmol l-1. 6. The primary fluid phosphate and chloride concentrations were the same in both sodium-replete and sodium-depleted animals and were unchanged by stimulation; the mean concentration of phosphate was 1.30 mmol l-1 and of chloride, 53.0 mmol l-1. In final saliva the phosphate concentrations were little changed but the chloride concentrations fell to an average value of 20.0 mmol l-1. In final saliva it was found that the summed sodium and potassium concentrations exceeded the summed chloride, bicarbonate and phosphate (in mequiv l-1) concentrations, on average by 13.9 mequiv l-1, regardless of sodium status or flow rate. 7. The results indicate that secretion by the sheep parotid can be accounted for in terms of the standard two-state model. Phosphate seems to enter the saliva only in the primary fluid and potassium and bicarbonate appear to enter at both primary and secondary sites; sodium and chloride enter at the primary level and can be reabsorbed in the ducts. Salt depletion causes the primary fluid concentrations of sodium and chloride to fall and the content of an unidentified solute to rise markedly while, at the ductal level, it causes normally quiescent sodium and potassium transport processes to become activated.
Production of bacteremia and meningitis in infant rats with group B streptococcal serotypes.
Group B streptococcal strains, representing the five major serotypes, were inoculated into infant rats by intranasal, oral, and intraperitoneal routes. Bacteremia regularly followed injection by the intraperitoneal route. Four strains (three of type III) isolated from human cerebrospinal fluid appeared more virulent for 5-day-old rats. Injection of fewer than 10 colony-forming units of one strain, a type III, led to bacteremia and death in 27% of animals. The cumulative bacteremia and mortality rate with this strain was 66% in animals given inocula of less than 10 to 10(3) colony-forming units. Bacteremia developed by 24 to 48 h with concentrations of greater than 10(5) colony-forming units per ml of blood, and death occurred soon afterward. Among bacteremic animals, positive cerebrospinal fluid cultures were found in 97%, and cerebrospinal fluid bacterial concentrations were equal to or exceeded bacterial counts in blood. The susceptibility of infant rats to infection with type Ia, Ic, or III strains was age dependent. Histopathological studies of the brain and meninges in 34 bacteremic animals with culture-positive cerebrospinal fluid revealed that 5- to 10-day-old animals had numerous bacteria distributed in a perivascular pattern but, with one exception, no leukocytic infiltration. In contrast, three of the 11- to 12-day-old and two 15-day-old animals had very thickened meninges infiltrated with polymorphonuclear leukocytes, macrophages, and bacteria.
Host immune status in uraemia III. Humoral response to selected antigens in the rat.
The humoral immune status of patients with uraemia is controversial. In the present experiments a carefully defined animal model, in which a chronic state of moderate and severe uraemia was induced, has been used to resolve conflicting views. The capacity of the uraemia host to respond to immunogenic stimulation was assessed by challenging uraemic animals with bacterial, viral, T cell-dependent and T cell-independent antigens. The experiments have shown that the immune responsiveness of animals with chronic severe uraemia, immunized with sheep red blood cells, Escherichia coli 075, keyhole limpet haemocyanin and phi X174 bacteriophage is comparable to those found in sham-operated and control groups. The results strongly suggest that uraemia per se does not affect the ability of the host to respond to a wide range of antigenic stimuli. This conclusion is important in that it provides a basis for assessing further the immune status of the uraemic host. If uraemic patients do have an immune deficit, one possible explanation is that uraemia potentiates the immunosuppressive activity of some drugs used in the clinical management of these patients.
The incidence of sensory integrative dysfunction among children with orofacial cleft.
Explore the source record for details and available documents.
Urinary kallikrein in postobstructive diuresis.
We studied urinary kallikrein excretion in the rat during unilateral release of 24-hr bilateral ureteral ligation (BUL). In six rats studied after 24 hr of BUL, the glomerular filtration rate was 20 per cent of that in the five sham-operated controls. In the BUL group, the urine flow rate was 5 fold greater, fractional sodium excretion 100 times greater, and fractional potassium excretion 5 times greater than in controls. Urinary kallikrein excretion in the BUL group was one-half that of the controls. However, urinary kallikrein excretion per functioning nephron was increased 3 fold in the BUL group. Five of six BUL rats with increased fractional sodium and water excretion also showed increased urinary kallikrein excretion/GFR when compared to controls. Our study suggests that after 24 hr of BUL in the rat, urinary kallikrein excretion is increased in relation to the remaining, functioning nephrons and suggests a role for the kallikrein-kinin system in the postobstructive salt and water losses.
Cause of ill health and natural death in badgers in Gloucestershire.
During the period 1973 to 1976 inclusive, 1206 badger carcases were examined for evidence of tuberculosis and other diseases. Tuberculosis was the major cause of natural death, killing 39 per cent of the natural death cases, followed by bite wounding and starvation. Road traffic accidents were the greatest single cause of death.
Mid systolic closure of aortic valve in hypertrophic cardiomyopathy. Echocardiographic and angiographic correlation.
Explore the source record for details and available documents.
Availability of adipose tissue tocopherol in the guinea pig.
Young guinea pigs were fed a purified diet containing vitamin E for 3 weeks and then fed the diet without vitamin E for 8 weeks. Levels of vitamin E in plasma and liver decreased to low values within a week. Depletion rates for heart and muscle were much slower, whereas the rate of loss from fat was negligible. In experiments with more mature guinea pigs and a depletion period of 4 months, the depletion rate of tocopherol from fat was also barely detectable. Both yound and mature guinea pigs developed myopathy after 8 weeks of depletion. Apparently, tocopherol in adipose tissue is not sufficiently available to maintain plasma tocopherol levels or to prevent signs of vitamin E deficiency. Even during fasting, adipose tissue tocopherol was not mobilized readily. During a 4 day fast, adipose tissue mass diminished considerably, but there was no appreciable loss of tocopherol.