Biomedical subjects

L G Dawes

Publications and source records attributed to L G Dawes.

24 records · Page 2Linked to original sources

PubMed1988

Increased total and free ionized calcium in a canine model of pigment gallstones.

It has been postulated that precipitation of calcium from bile is important in the formation and growth of pigment gallstones, since they contain large amounts of calcium. Therefore we studied biliary total calcium [( Ca]) and free ionized calcium [( Ca++]) concentrations in 12 dogs before and after 6 weeks of a methionine-deficient, high-cholesterol diet. In all dogs pigment gallstones and sludge formed while the animals were on the diet. Although gallbladder function--as assessed by biliary pH, total bile salt, and bile electrolyte concentrations--was minimally altered by the diet, both [Ca] and [Ca++] increased significantly, from 10.16 +/- 0.19 to 13.16 +/- 0.57 mmol/L and 3.02 +/- 0.07 to 3.76 +/- 0.17 mmol/L, respectively. The observed increases in calcium concentrations, and specifically in [Ca++], early during stone formation in this model would increase the likelihood that bile would become saturated with at least one calcium salt and support the hypothesis that calcium is important in pigment gallstone formation.

Animals↗

PubMed1986

Cystic masses of the spleen.

Cystic masses of the spleen are unusual, and identification of their origin is critical to proper management. Presenting symptoms frequently are due to compressive effects of the mass or are due to infection. These cystic splenic masses are most commonly secondary cysts that lack a true epithelial lining and are usually related to prior splenic injury. Primary splenic cysts are rare and have an epidermal lining. Computed abdominal tomography outlines the anatomy and character of cystic masses of the spleen. Cystic splenic masses that are large, inflammatory in origin, involve the splenic hilum, or are infected, should be excised by splenectomy. Cysts localized to a single pole can be treated by partial splenectomy. An experience with three illustrative cases is presented.

Adult↗

PubMed1986

The risk of infection after colon injury.

We reviewed 137 patients with colon injury and applied multiple regression analysis to determine the influence of various parameters on colon-related infection. The complications of intra-abdominal abscess, wound infection, and peristomal abscess occurred in 25% of patients. The mortality rate was 3.6%, and four of five late deaths were caused by infection. Multiple regression analysis identified the amount of blood transfused, patient age, number of associated injuries, and injury to the spleen as significantly associated with infection (p less than 0.05). In the absence of these risk factors, the likelihood of infection is low, suggesting that primary repair or resection and anastomosis are safe methods of management for colon injury. When these factors are present, the risk of infection is high, and colostomy is the preferred method of management.

Abscess↗

PubMed1985

Splenic phagocytic function after partial splenectomy and splenic autotransplantation.

We investigated splenic reticuloendothelial activity after splenic preservation procedures to determine their effect upon the phagocytic function of the spleen. We performed the following procedures in Sprague-Dawley rats: sham laparotomy, total splenectomy, hemisplenectomy, subtotal splenectomy, or total splenectomy with intraperitoneal splenic autotransplantation. At nine weeks after operation, phagocytic function of the spleen was determined by measuring radiocolloid uptake. Mean (+/- SEM) splenic phagocytic indices for sham laparotomy (41.2 +/- 2.9), hemisplenectomy (44 +/- 2.9), and subtotal splenectomy (43.2 +/- 5.2) were similar; however, the phagocytic index was reduced markedly after autotransplantation (15.8 +/- 2.2). These data demonstrate that the phagocytic function of the spleen after hemisplenectomy and subtotal splenectomy correlates highly with the weight of the splenic remnant; however, phagocytic function after autotransplantation remains reduced even after accounting for differences in splenic weight.

Animals↗

PubMed1985

Response to immunization after partial and total splenectomy.

Survival after infection from Streptococcus pneumoniae in both animals and man is influenced by the amount of splenic tissue. We investigated the effect of differences in splenic weight upon the antibody response to immunization and the effect of immunization upon survival after pneumococcal challenge. Young Sprague-Dawley rats had either sham operation, hemisplenectomy, splenectomy with splenic autotransplantation, or total splenectomy. Nine weeks later, rats were immunized with a heat- and formalin-killed type-specific pneumococcal vaccine. Antibody response measured by radioimmunoassay was similar in all operative groups and was significantly higher than in nonimmune rats (P less than 0.01). Splenic weight was less after hemisplenectomy or autotransplantation than in sham-operated animals (P less than 0.01). Immunization improved survival after live pneumococcal challenge in rats that had autotransplantation and total splenectomy (P less than 0.001). Our results demonstrate that splenic weight does not affect the antibody response to pneumococcal immunization in rats. Immunization improves survival after bacterial challenge in susceptible animals and minimizes the detrimental effect of reduction in splenic mass.

Animals↗

PubMed1985

The influence of splenic weight and function on survival after experimental pneumococcal infection.

Splenectomy impairs survival after pneumococcal challenge in rats, while preservation of sufficient splenic tissue can be protective. This study investigated the effects of methylcellulose on stimulation of splenic weight, splenic histology, reticuloendothelial (RE) activity, and survival after pneumococcal infection. Methylcellulose increased spleen weight four- to five-fold but did not improve RE function or survival after infection. These parameters correlated best with the weight of the remnant in animals that did not receive methylcellulose. The functional limitations of splenic autotransplants were not corrected by methylcellulose stimulation of splenic weight. Preservation of a splenic remnant with intact blood supply is preferable to autotransplantation of the spleen to conserve RE capability.

Animals↗