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Biomedical subjects

D Kelly

Publications and source records attributed to D Kelly.

At least 181 records · Page 10Linked to original sources

Additive and synergistic interaction of atrial natriuretic peptide and volume expansion.

To investigate whether atrial natriuretic peptides (ANP) are entirely responsible for the natriuresis of volume expansion (VE), we studied the natriuresis from acutely snared and nonsnared kidneys of rats undergoing sustained saline VE and subsequent infusion of maximal doses of ANP (atriopeptin II), or vice versa. Fractional excretion of Na (FENa) was increased from control (0.15 +/- 0.03%) to 4.6 +/- 0.6% by VE and to 10.9 +/- 1.5% by subsequent ANP infusion. With ANP alone FENa increased from control (0.24 +/- 0.04%) to 2.6 +/- 0.3%, and to 10.8 +/- 0.9% with VE, showing additive effects by both. Natriuresis with VE was significantly greater than with ANP alone (P less than 0.01) and both exhibited synergism, producing significantly greater natriuresis in the presence of the other than alone (P less than 0.05 for both). A reduction in perfusion pressure inhibited the effects of ANP and reduced that of VE. Natriuresis was produced by ANP independently of changes in glomerular filtration rate. It is concluded that 1) VE and ANP produce natriuresis by different renal mechanisms and that therefore, ANP can only account for part of the natriuresis of sustained VE; 2) the two have a synergistic interaction on natriuresis, probably through an intrarenal mechanism.

Animals↗

Non-seminomatous germ cell testis cancer in Ireland (1980-1985). Management, results and prognostic variables with relevance to national management protocols.

All non-seminomatous germ cell testis cancer in Ireland (1980-1985) was analysed (n = 131) and 3-year survival was: stage I = 95% (n = 58), stage II = 54% (n = 36), stages III and IV = 24% (n = 34). Countrywide results were not as favourable as those achieved in specialist units and this supports the development of a national strategy to maximise disease control. No management protocols existed during this study and the variety of approaches helped to identify the most suitable types of treatment in this broad context.

Clinical Protocols↗

The effects of in vivo antibiotics on neutrophil (PMN) activity in rabbits with peritonitis.

Antibiotics play an important role in helping the host fight infection; however, the direct cellular effect of antibiotics on polymorphonuclear cells remains undefined. Adherence, chemotaxis, phagocytosis, and superoxide anion production are important steps in the cascade of events initiated by the polymorphonucleocyte in bacterial killing. Previous studies have shown inhibition as well as stimulation of neutrophil antibacterial therapy by antibiotics. Peritoneal and blood polymorphonuclear neutrophils (PMN) respond differently to peritonitis and to external agents. The purpose of this study was to investigate the effects of in vivo clindamycin and netilmicin on infected rabbit peritoneal and blood polymorphonuclear adhesiveness, phagocytosis, chemotaxis, and superoxide anion production. Peritoneal and blood PMNs were obtained from rabbits which had undergone appendiceal devascularization 18 hr earlier: antibiotics were administered intramuscularly 1 hr prior to appendectomy and every 8 hr postoperatively for 5 days; these PMNs were compared to infected rabbits which did not receive antibiotics. Clindamycin and netilmicin in vivo cause significant inhibition of phagocytosis, peritoneal adhesiveness, and, when used in combination, blood adhesiveness and peritoneal superoxide anion production. No effects were seen on chemotaxis. Based on this data we conclude that antibiotics, while vitally important in fighting infections, may in and of themselves be agents of immunosuppression at the cellular level.

Animals↗

The effect of dexamethasone in vivo on blood and peritoneal neutrophils (PMN) in rabbits with peritonitis.

Neutrophils play an essential role in the host's defense against infection. Our previous studies have shown that blood and peritoneal neutrophils (PMN) have different basal activities and responses to infection. We also demonstrated that peritonitis produces divergent changes in the cellular function of PMN both in the blood and in the peritoneal fluid. Steroids are well documented to cause immunosuppression both clinically and, more variably, at the cellular level. Understanding the mechanism of steroid-induced immunosuppression in surgical infection may impart insight on the management of this condition. Using a model of surgical peritonitis, we studied the effects of immunosuppression on rabbit blood and peritoneal PMN. Blood and peritoneal PMNs were harvested after the development of fibrinopurulent peritonitis. Rabbits were divided into two groups: immunosuppressed and control. Immunosuppression was accomplished by intramuscular injection of dexamethasone (2 mg/kg) for 10 days preoperatively and 10 days postoperatively. Purified PMNs were studied for phagocytosis, adhesiveness, superoxide anion production and chemotaxis from both groups. Survival was computed from the number of days the rabbit survived after the operation up to a total of 10 at which time they were sacrificed. Immunosuppression with dexamethasone resulted in inhibition of peritoneal phagocytosis and peritoneal adhesiveness; there were no changes in blood adhesiveness nor blood phagocytosis. Also, there was no significant change in superoxide anion production nor in chemotaxis. Survival of the rabbits was significantly reduced when treated with dexamethasone.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Near-haploidy in a case of plasmocytoma.

Chromosome studies of a solitary plasmocytoma in the femoral bone revealed a near-haploid chromosome number of 31-32 with a loss of one homolog of each chromosome pair except #1, #7, #9, #15, #19-21, and the sex chromosomes (XY). The cytogenetic findings have been compared with 16 cases of near-haploid neoplasms from the literature studied using banding techniques. A common feature present in 13 of the 16 cases reported was found to be disomy 21; the only chromosomes consistently present in one copy in all neoplasms were #2, #3, #4, and #5.

Chromosome Aberrations↗

Comparison of blood and peritoneal neutrophil activity in rabbits with and without peritonitis.

The neutrophil (polymorphonuclear cell, or PMN) function is an essential component of the host defense against infection. However, infection itself may alter PMN activity. To investigate both the effects of infection on PMN activity and PMN activity on survival, we evaluated control and infected blood and peritoneal PMN phagocytosis, chemotaxis, and superoxide anion production in rabbits with and without peritonitis. Control blood and peritoneal PMNs were obtained from noninfected rabbits which were subjected to intraperitoneal infusion of sterile hypertonic saline. Infected blood and peritoneal PMNs were obtained from rabbits which had undergone appendiceal devascularization and ligation 18 hr earlier. Phagocytosis was similar in all groups except for a threefold increase in normal peritoneal PMNs. Chemotaxis was inhibited by infection in the blood and peritoneal PMNs. Normal peritoneal PMNs also had decreased chemotaxis. Superoxide anion production was comparable in the infected and control blood; however, both control and infected peritoneal PMNs had elevated superoxide anion production. Of the infected rabbits, four died in 5 days or less. Of the six that lived, two developed intraabdominal abscesses. Blood and peritoneal PMN activity was similar in all rabbits despite their outcome. We conclude that (1) blood and peritoneal PMNs have different basal activities and responses to infection; (2) the milieu of the peritoneal cavity appears to alter the PMNs present; and (3) PMN activity did not predict morbidity or mortality.

Animals↗

Identification of a high-risk group for sudden infant death syndrome among infants who were resuscitated for sleep apnea.

Of the 1,153 infants who completed monitoring by Aug 1, 1984, through our program at Massachusetts General Hospital, 76 infants had an initial apnea spell during sleep which was characterized by a change in tone and color, was unresponsive to repeated vigorous stimulation, and was terminated only after mouth to mouth resuscitation. The infants were hospitalized for observation and evaluation, and no cause could be identified. All were discharged on a home apnea or cardiorespiratory monitor, and subsequent episodes of apnea and/or bradycardia were reviewed. We grouped infants based on the intervention used to terminate subsequent episodes: Group 1, resuscitation; group 2, vigorous stimulation; and group 3, neither resuscitation or vigorous stimulation. There was no significant difference in clinical features or in the results of the initial evaluation in groups 1 and 2, compared with group 3. However, the mortality rate was significantly higher in group 1 (4/13) and group 2 (3/12) than in group 3 (3/51) (P less than .007). Siblings of victims of sudden infant death syndrome (n = 8) were at a significantly higher risk of an adverse outcome (two deaths and four resuscitations) than nonsiblings (P less than .02). A seizure disorder that developed during monitoring was associated with a high mortality (4/11 v 6/65, P less than .02). We conclude that these relatively rare infants who have sleep-onset apnea that responded only to resuscitation and have a subsequent similar episode or are siblings of victims of sudden infant death syndrome or develop a seizure disorder during monitoring have a very high risk of dying (31%, 25%, and 36% respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Bradycardia↗

The effect of an acute phase reaction and BCG innoculation on factor VIII in the guinea-pig.

Factor VIII antigen (VIII:Ag) and vWF:Antigen (vWF:Ag) were measured in guinea-pigs treated with intraperitoneal turpentine to induce an acute phase reaction, and with BCG to stimulate the reticulo-endothelial system. In the turpentine treated animals there was a significant rise of fibrinogen at 24 and 48 hours after injection (1.43 +/- 0.01 g/l) when compared with controls (1.15 +/- 0.1 g/l), mean +/- SEM n = 3 p 0.01). There was no change in plasma VIII:Ag but a significant rise of vWF:Ag at (2.0 +/- .3 units/ml) when compared with controls (1.1 +/- 0.05 units/ml, mean +/- SEM n = 3 p less than 0.001). Examination of perfused guinea-pig organs showed a reduction in hepatic VIII:Ag (82%) and vWF:Ag (90%) and a 76% increase in splenic vWF:Ag only in the turpentine treated animals. Distribution of 125I Albumin to detect trapped blood in tissues demonstrated efficient clearance of blood by perfusion. There was no change in the plasma concentration of either VIII:Ag or vWF:Ag following BCG inoculation but there was a 45% increase in the splenic concentration of vWF:Ag. It is concluded that only the factor vWF:Ag and not the factor VIII:Ag component of the factor VIII complex is an acute phase reactant in guinea-pig and that this may be due to increased synthesis of vWF:Ag by vascular endothelium in the spleen. Although BCG inoculation may have stimulated synthesis or storage of vWF:Ag in the spleen it did not have an appreciable effect on the plasma concentration of either VIII:Ag or vWF:Ag.

Animals↗

Blood and peritoneal neutrophil (PMN) adherence in rabbits: the effects of hemoglobin, peritoneal fluid, and infection.

Neutrophil (PMN) adherence is an important first step in PMN migration. Peritoneal fluid and hemoglobin have been implicated as inhibitors of blood PMN function. The purpose of this study was to evaluate the effects of peritoneal fluid and hemoglobin on PMN adherence in both blood and peritoneal PMNs. Adherence was measured by nylon fiber filtration. Control blood PMNs were obtained from rabbit heparinized blood. Control peritoneal PMNs were obtained by saline lavage 18 hr after the intraperitoneal instillation of hypertonic saline. Infected blood and peritoneal PMNs were similarly obtained from rabbits which had undergone appendiceal devascularization 18 hr earlier. Blood and peritoneal PMNs were tested in normal saline, serum, hemoglobin, and peritoneal fluid from infected and noninfected rabbits. Cell adhesiveness of blood and peritoneal neutrophils from infected and noninfected rabbits was similar in all groups. In normal saline and serum, cell adhesiveness was approximately 70%. In hemoglobin and peritoneal fluid, all groups of neutrophils showed a statistically significant decrease in cell adhesiveness. Based on these data we conclude: (1) Blood and peritoneal PMNs with and without infection have similar adherence. (2) Both hemoglobin and peritoneal fluid inhibit PMN adherence.

Animals↗

Mitogenic inhibition and effect on survival of mice bearing L1210 leukemia using a combination of dehydroascorbic acid and hydroxycobalamin.

The present study was designed to test the effect of a combination of dehydroascorbic acid (DHA) and hydroxycobalamin (vitamin B12) on the survival of mice bearing L1210 leukemia. Results showed a significant increase in survival of treated mice compared with controls (p less than or equal to 0.0001) (Student's t-test). This positive effect was significantly lost when DHA was substituted by ascorbic acid (AA) in the same experimental conditions. In vitro findings also revealed that the DHA-B12 combination specifically inhibited mitoses of L1210 cells while non-neoplastic L929 cells were not affected.

Animals↗